Pediatric intensive care unit (PICU) survivors are at risk for prolonged morbidities interfering with daily life. The current study examined parent-reported health-related quality of life (HRQoL) in former critically ill children and parents themselves and aimed to determine whether withholding parenteral nutrition (PN) in the first week of critical illness affected children’s and parents’ HRQoL 2 years later.n = 1158) were included. Their HRQoL outcomes were compared with 405 matched healthy controls. At PICU admission, children had been randomly assigned to early-PN or late-PN. In the early-PN group, PN was initiated within 24 h after PICU admission. In the late-PN group, PN was withheld for up to 1 week in the PICU. Parents completed the Infant Toddler Quality of Life Questionnaire  or the Child Health Questionnaire-Parent Form 50 . Besides, they completed the Health Utility Index (HUI) and the Short Form Health Survey (SF-12) regarding their child’s and their own HRQoL, respectively.Children who participated in the pediatric early versus late parenteral nutrition in critical illness (PEPaNIC) trial and who were testable 2 years later  scored worse for growth and development and older children (4–18 years old) scored worse for role functioning and mental health. Parents’ own mental and physical HRQoL was comparable to that of healthy control parents. No HRQoL differences were found between children in the late-PN and those in the early-PN group.Parent-reported HRQoL of children 2 years after critical illness was impaired compared with healthy controls. In relation to their child’s HRQoL, parents reported impairments in emotions, personal time, and family activities; however, their own HRQoL was not impaired. Withholding PN in the first week during critical illness had no impact on longer-term HRQoL of the child.NCT01536275. Registered 22 February 2012Clinical trials,  Improvements in care for critically ill children have led to lower mortality rates in our pediatric intensive care units (PICUs) . NeverthWe recently showed that parents reported lower HRQoL in PICU survivors, 6 months after PICU admission, compared with healthy children. Parents themselves reported better scores for physical HRQoL and worse scores for mental HRQoL compared with the general population . This coThe pediatric early versus late parenteral nutrition in critical illness (PEPaNIC) multicenter, randomized controlled trial (RCT) showed that withholding supplemental parenteral nutrition (PN) during the first week in the PICU resulted in better short-term outcomes, with a reduced incidence of new infections, a shorter stay at the PICU, and reduced direct healthcare costs, compared with initiating parenteral nutrition on the day of admission to the PICU , 11. ImpThis study is part of the pre-planned 2-year follow-up of the PEPaNIC trial that enrolled 1440 critically ill children admitted to the three participating PICUs  between June 18, 2012, and July 27, 2015. The full study protocol with sample size calculation, short-term outcomes, and 2-year medical and neurocognitive outcomes have been published , 12, 13.Children who had participated in the PEPaNIC trial and who were alive and neurocognitively testable at 2-year follow-up were also eligible for the current study. Four hundred and five healthy control children, who had never been admitted to a neonatal or pediatric ICU, were recruited for a medical and neurocognitive assessment similar to that of the post-PICU patients. These children were demographically matched to the patients for age and gender. To control as much as possible for genetic and socio-economic/environmental background, siblings and relatives of the patients were preferably recruited into this control group, besides unrelated children recruited from the same geographic area.From August 2014 through January 2018, all PICU survivors and their parents were first approached through a standardized patient information letter after screening for survival status was performed. When children’s neurocognitive functioning was not testable as determined by the physician and confirmed by the parents, they were not included in the analyses. Children who were neonates (0 to 6 months old) at the time of the PEPaNIC trial were tested at the age of 2.5 years due to the age-limits of the neurocognitive tests. When consent was obtained, they were subsequently contacted by phone to schedule an appointment for the follow-up assessment that was performed either at the hospital or at the patient’s home. Parents received the HRQoL measurements along with the confirmation letter of the appointment for follow-up assessment. One of the parents completed the questionnaires at home and handed them over to the researcher on the day of the follow-up assessment. Written informed consent was obtained from the parents or legal guardians and/or from the adolescent according to local regulations. The institutional review boards at each participating site approved this follow-up study.The type of validated parent-reported questionnaires assessing the child’s HRQoL depended on the age of the child. Parents of patients 2.5–3 years old completed the Infant Toddler Quality of Life Questionnaire (ITQOL) about their child’s HRQoL , consistThe Health Utilities Index Mark 2 and 3 (HUI2 and HUI3) are based on the 15-item HUI questionnaire and are two different classification systems that together provide a combined view of the child’s HRQoL and provide a more objective way to measure the health status of the child. The HUI2 and HUI3 comprise respectively 6 or 7 function-attributes based on single items. Scores range from 1  to 4, 5, and 6  and 1 weighted multi-attribute utility function with ranges of minus 0.36 (score worse than dead) to 1.00 . In the current study, since children were matched with healthy control children, the HUI2 and HUI3 were assessed in children of all ages.The fraction of missing HRQoL data per variable was determined and analyzed to examine whether they were missing at random or not at random. In order to avoid selection bias, multiple imputation by chained equation (MICE) of HRQoL variables was performed when ≥ 70% of the data was available . The numt test or Wilcoxon rank-sum test as appropriate. All multivariable analyses were adjusted for the baseline risk factors described in Additional file p values ≤ 0.05 were considered statistically significant. To explore whether the results of the SF-12 were affected by the fact that some parents completed this questionnaire twice for two children participating in the study, one-way analyses of variance were done on three of the 21 imputed datasets as a sensitivity analysis. This trial is registered with ClinicalTrials.gov, NCT01536275.To analyze the differences in HRQoL scales available for all ages between post-PICU patients and healthy control children and to investigate differences between patients randomly allocated to late-PN or early-PN during PICU stay, multivariable linear analyses were done on 21 imputed datasets with the beta-estimates reported as pooled results, preceded by a pooled univariable comparison with use of Student p values > 0.15).Of the 1158 children who were alive and testable 2 years later, a total of 391 children in the early-PN group and 395 children in the late-PN group participated in the 2-year PEPaNIC follow-up study (Fig. n = 111 parents who completed the SF-12 two times or more showed no differences in results (Additional file Overall, critically ill children had worse outcomes at 2-year follow-up for parent-reported HRQoL compared with healthy control children Table . For theParents of critically ill children in the late-PN group overall reported comparable HRQoL scores as parents of critically ill children in the early-PN group, in univariable and multivariable analyses Table .Two years after children were included in the PEPaNIC trial, significant lower scores were found for post-PICU survivors compared with healthy control children on physical and general health-related HRQoL domains and single HUI scores. Besides, in younger post-PICU children, parent-reported growth and development was impaired. We previously showed that post-PICU children had worse outcomes for height, body weight, and neurocognitive development compared with healthy controls . The preImpairments in physical HRQoL and in general health were still present in this study but parents reported more positive change in health on the single item scale “change in health” compared to 1year ago. In our previous 6-month PICU follow-up study , parentsIn this study, parents reported that critical illness of their child had a negative impact on emotional wellbeing, personal time, and on activities with the family which is similar to a previous study in parents of children admitted to the PICU for cardiac arrest . InteresWithholding PN during the first week of critical illness had no impact on parent-reported HRQoL of the child compared with early administration of PN. This contrasts with the favorable outcomes on parent-reported executive functioning, in particular better inhibitory control, in critically ill children of the late-PN group . This maTwo years after PICU stay, children showed most impairments in physical HRQoL domains and therefore, follow-up programs should focus on these physical problems after PICU admission . In addiA strength of the current study is that the sample size was very large compared with other studies examining HRQoL in PICU survivors. Furthermore, we included the heterogeneous group of PICU patients and extensively adjusted the analyses for baseline and short-term follow-up risk factors for lower HRQoL. Hence, the results are generalizable to the impact of a PICU admission on long-term HRQoL , especiaA limitation of the current study is the dependence on parent-reported outcomes since the majority of the children were too young to be able to assess their own HRQoL. Re-evaluation of the children when they are able to assess their own HRQoL in self-reports will provide further valuable information regarding HRQoL on the longer term after critical illness. Furthermore, children who were too disabled to test were not included in the current analyses. In our opinion, this would have introduced bias and limited the generalizability of the results since questionnaires assess to what extent children are able to participate in society. For example, parents are asked whether their child was limited by their health status in doing their homework or activities with friends in the last 4 weeks.Two years after critical illness, children showed an impaired parent-reported HRQoL, mainly on physical domains and general health. In relation to the critical illness of their child, parents reported impairments in emotions and personal time. However, parents’ own HRQoL appeared comparable to that of parents of healthy control children. Lastly, withholding PN in the first week during critical illness had no impact on HRQoL of the child on the longer term.Additional file 1. Psychometric characteristics of the questionnaires and additional information about variables for analyses.Additional file 2. Detailed demographic information regarding socioeconomic status and diagnostic category.Additional file 3. Pooled univariable analyses of the differences in HRQoL outcomes between study groups.Additional file 4. Sensitivity analyses of SF-12 outcomes of parents who have only one child in the study.Additional file 5. Scales and score interpretation of the questionnaires.


There are increased risks of contracting COVID-19 in hospitals and long-term care facilities, particularly for vulnerable groups. In these environments aerosolised coronavirus released through breathing increases the chance of spreading the disease. To reduce aerosol transmissions, the use of low dose far-UVC lighting to disinfect in-room air has been proposed. Unlike typical UVC, which has been used to kill microorganisms for decades but is carcinogenic and cataractogenic, recent evidence has shown that far-UVC is safe to use around humans. A high-fidelity, fully-coupled radiation transport and fluid dynamics model has been developed to quantify disinfection rates within a typical ventilated room. The model shows that disinfection rates are increased by a further 50-85% when using far-UVC within currently recommended exposure levels compared to the room’s  ventilation alone. With these magnitudes of reduction, far-UVC lighting could be employed to mitigate SARS-CoV-2 transmission before the onset of future waves, or the start of winter when risks of infection are higher. This is particularly significant in poorly-ventilated spaces where other means of reduction are not practical, in addition social distancing can be reduced without increasing the risk. In these environments, and some other populated spaces, social distancing may be impractical and hence the infection controls must focus on a combination of personal hygiene and correct use of personal protective equipment (PPE). With major shortages seen in many countries, most visibly the supply of N95 face masks3, availability of adequate PPE has remained a major concern throughout the crisis. As many countries exit their lockdowns, fatigue and habituation within the population may lead to increased complacency in hygiene measures, and hence, along with reducing the burden on PPE, controls like ultraviolet germicidal irradiation4 (UVGI) have been considered. UVGI has previously been considered as a way of controlling airborne viruses during a pandemic if effective vaccines or antiviral drugs are not available5. Used for over a hundred years, UVGI-based disinfection traditionally relies on cancer-causing 254 nm UVC light thereby rendering it incompatible for use around people. Fortuitously, recent advances in UV lamp technology, in particular excimer lamps8 and light-emitting diodes11, now permit narrow bandwidth, short wavelength UVC (207–222 nm) to be generated. As these far-UVC wavelengths cannot penetrate either the human stratum corneum or ocular tear layer12, they are not carcinogenic or cataractogenic17 and can therefore be safely used in people-facing applications18.The coronavirus pandemic has put hospitals and long term care facilities under considerable stretch. Aerosolised coronavirus released through breathing was probably a significant cause of this19, diffusion radiation models20, and, potentially, empirical data taken from physical measurements23. The use of LES models24 provide more detailed descriptions of viral transport over other modelling methods, such as Reynolds Averaged Navier–Stokes23 or analytical zone-mixing methods25, and despite their increased computational requirement, and hence limited use, their importance is now being recognised in the field of atmospheric viral transport predictions24.Quantifying the rate of far-UVC viral inactivation within a general room is complex and multiphysics in nature. It requires both radiation and atmospheric flow calculations where objects within rooms add complication as they obstruct both the light propagation and air flows, thus casting shadows and inducing eddies and turbulent structures. High fidelity modelling is therefore essential, and here we present the first coupled radiation transport and fluid dynamics simulator, based on the Boltzmann Transport and Navier–Stokes equations with integrated Large Eddy Simulation (LES) turbulence models, for viral inactivation within atmospheres. Fully resolved spatially distributed far-UVC intensities enable more accurate predictions of virus removal over simplified 26. The source of far-UVC originated from a lamp positioned in the top right corner of the room. The power investigated yielded far-UVC intensities of approximately 27. A far-UVC inactivation value of 12.This model was used to study the far-UVC inactivation of aerosolised human coronavirus in a single occupancy private room, a representative environment found in hospitals and long-term care facilities. Conducted in the two-dimensional domain shown in figure The spatially varying intensity of the far-UVC field produced by the lamp is presented in Fig. This radiation field is considered constant in time and is used in all subsequent analysis. Figure Figure The graphs presented in figure Figure 12, we have shown that the contention that it can be reduced by 99.9% in public spaces within 25 minutes12 is situation dependent. In a representative environment in a hospital or a long-term care facility, the nature of the viral source and the interaction of ventilation with far-UVC illumination all strongly influence the efficacy of far-UVC germicidal irradiation.A plethora of approaches are being used to mitigate transmission of aerosolised SARS-CoV-2 coronavirus. Others are proposed. Most of these follow one or more of three key principles: minimise time exposed to the virus (limit interactions), maximise distance from sources of virus , or shield yourself from the virus (wear PPE). Whilst these are all effective measures, their success is tied to human behaviour and hence at risk from complacency. Unlike these active measures, passive use of in-room far-UVC provides an invisible barrier. Whilst the viability of human coronaviruses can be successfully reduced by far-UVC12. However, it has been shown that this is only the case for a single seeding of virus particles such as those which occur from a single unobstructed breath. Such rapid reductions could therefore be achieved in situations where face masks or breathing apparatus are removed for a short period of time. Given the normal pattern of unobstructed human breathing constantly seeds a poorly-ventilated room with new virus, concentrations ultimately reach an equilibrium. With far-UVC illumination at currently recommended exposure levels, not only is this equilibrium reached more quickly, but the viral concentration is approximately one order of magnitude lower than it would be without. In highly-ventilated rooms, reductions in in-room viral concentration for both breathing scenarios are comparable to those from far-UVC at currently recommended exposure levels in poorly-ventilated rooms. Even in highly-ventilated rooms where satisfactory levels of removal may already exist, far-UVC illumination will further reduce viral concentrations by around 57%.For poor ventilation and far-UVC human exposures at the currently recommended level, total viable viral concentration is reduced exponentially in comparable times to those previously stated29. Finally, unlike face masks, far-UVC is a passive control from the perspective of the individual. Due to it having a similar efficiency to an N95 mask, it could replace them in some situations, reducing the demand for PPE supplies, and lessening the damage that PPE disposal is causing to the environment30.Several practical implications of far-UVC illumination in reducing in-room transmission of SARS-CoV-2 are clear. Firstly, with both high and low ventilation, far-UVC will reduce aerosolised SARS-CoV-2 concentrations within a metre of the patient to levels below that in regions beyond a metre without far-UVC. Employment of far-UVC could therefore have a bearing on the social distancing limits currently used in many countries, or at least further reduce risks of transmission at these distances. Secondly, in all scenarios described, far-UVC will reduce in-room SARS-CoV-2 concentrations to levels comparable to that provided practically by breathing through an N95 maskS of a viral population subjected to some UVC radiation intensity over a time period of t seconds is governed by the equation,4. The UVC intensity with dimension Z have been provided in12 which states a value The survival rate The intensity of the far-UVC field is described through the mono-energetic, fixed source Boltzmann transport equation,The solution to Eq.  was obtaThe scalar quantity of the spatially dependent far-UVC intensity, mentclass2pt{minimp denotes the pressure. The kinematic viscosity of air is denoted by Computational fluid dynamics is a numerical approach for simulating the movement of air based on the conservation laws of mass, momentum, and energy. Ignoring the temperature influences, the airflow motion is governed by the following form of the unsteady, incompressible Navier-Stokes equations:31. A regular mesh of 31.In the simulations presented a finite element discretisation of the governing equations  was usedquations –5 and th26.The distribution and transportation of the airborne virus was included in the room ventilation model. The spatially dependent scalar concentration of the virus was described through the equation,In the results presented the same spatial and temporal discretisation as the fluid model were used. The far-UVC intensity field in Eq. , which w32, and evaporation of droplets have also been omitted from consideration. The droplet’s convection with the air flow is the dominant transport process, and so gravitational effects are small, and any size reduction due to evaporation increases this effect. The resting of droplets on surfaces are currently not included in this model as the analysis centres on the droplets that remain airborne. However, the percentage of those droplets that do come to rest will still be subjected to far-UVC irradiation, but will not be removed through ventilation. Therefore the estimates of removal via the far-UVC are conservative, and the true removal rates are potentially greater.The use of Eq.  implies Table


The COVID-19 pandemic has caused more than 462,417 deaths worldwide. A large number of patients with severe COVID-19 face death in hospital. Hospice care is truly a philosophy of care that delivers patient-centred care to the terminally ill and their families. Hospice care could provide many benefits for patients, families, and for hospice caregivers. The aim of this study is to investigate hospice care self-efficacy and identify its predictors among Chinese clinical medical staff in COVID-19 isolation wards of designated hospitals.A cross-sectional design was used. The Hospice Care Self-Efficacy, Self-Competence in Death Work Scale, Positive Aspects of Caregiving, and Simplified Coping Style Questionnaires were administered between February and April 2020. A total of 281 eligible medical staff responded to the questionnaires, with a response rate of ≥78.9%.P < 0.001), positive aspects of caregiving , positive coping , giving hospice care to dying or dead patients before fighting against COVID-19 , occupational exposure while fighting against COVID-19 , holding respect for life and professional sentiment as motivation in fighting against COVID-19 , and grade of hospital employment . The variables co-explained 58.7% variation of hospice care self-efficacy.The mean score of hospice care self-efficacy was 47.04 (SD = 7.72). Self-efficacy was predicted by self-competence in death work (B = 0.433, Clinical nurses and physicians fighting COVID-19 reported a moderate level of hospice care self-efficacy during this pandemic. Exploring the traditional Chinese philosophy of life to learn from its strengths and make up for its weaknesses and applying it to hospice care may provide a new framework for facing death and dying during the COVID-19 pandemic. Continuous hospice care education to improve self-competence in death work, taking effective measures to mobilize positive psychological resources, and providing safer practice environments to avoid occupational exposure are also essential for the improvement of the hospice care self-efficacy of clinical nurses and physicians. These measures help caregivers deal effectively with death and dying while fighting against the COVID-19 pandemic. Coronavirus disease 2019 (COVID-19), the third known zoonotic coronavirus disease after severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS), is an acute, infectious pneumonia caused by a novel coronavirus . As of 1Hospice care generally falls into the category of palliative care . It is aHospice care is most often provided at home; however, it can also be provided in an inpatient setting, including hospital, nursing home, or stand-alone hospice facilities. Hospice care requires a multidisciplinary team-based approach to care and relies on families, friends, and other loved ones as well as volunteers to assist in quality care . HoweverNurses and physicians involved in fighting against pandemics such as the COVID-19 suffer from high physical and mental workloads, stress, and risk of infection –20, all Self-efficacy refers to the personal judgment of how well an individual can execute required courses of action to deal with prospective situations, and the hospice care self-efficacy is targeted at hospice care and addressed the health workers’ confidence regarding the provision of mental and spiritual care for the terminally ill and their family members . StudiesThe aim of this study was to investigate hospice care self-efficacy and to identify its predictors among Chinese clinical medical staff in the COVID-19 isolation wards of designated hospitals. The findings may provide clinical managers in China and in other countries with experience on psychological strategies regarding the fight of medical staff against COVID-19 so as to develop more effective strategies to cope with COVID-19 deaths and dying patients.This was a cross-sectional questionnaire survey. The data were collected from a large number of clinical medical staff fighting against COVID-19 pandemic between February and April 2020 in China. These medical staff were invited to take part in this study if they: (1) had nurse or physician qualifications granted by the National Health Commission (NHS); (2) had assisted and worked in the COVID-19 isolation ward of COVID-19 designated hospitals, both in Hubei province and in other local provinces. We excluded medical personnel who were not involved in the treatment and care of COVID-19 patients in the isolation wards of designated hospitals, including logistics personnel and medical technicians. Ethical approval was obtained from the Medical Ethics Committee of Guizhou Medical University in Guiyang, China. The research conformed to the provisions of the Declaration of Helsinki in 1995 (as revised in Edinburgh in 2000).The data were collected by combining a convenience sampling method and a snowballing sampling method. We collected all participant information using the Questionnaire Star, a professional online survey platform developed by Changsha Ranxing Information Technology Co. (China). This survey platform has 33.75 million users and has previously been used to collect 2.334 billion responses to questionnaires in China. The data collection process was as follows:We edited our in-house e-questionnaire using the platform and generated a link that would provide access to our e-questionnaire via WeChat, an instant mobile messaging software with the largest user groups in China. The questionnaire stated the purpose and methods of our study. The risk of participating in the survey was described to acquire informed consent on the first page, and each participant could decide of their own free will whether to join our survey. They also had the right to quit the survey at any time without any further consequences. If the potential participants were not willing to join or would like to quit the survey, they could directly exit the questionnaire link to drop out. Each participant would also have to answer two questions ?’, and ‘Have you worked in the COVID-19 isolation ward of designated hospitals?’) at the top of the questionnaire to ensure that the inclusion and exclusion criteria of our study would be met.Medical staff who assisted and worked at COVID-19 designated hospitals in Hubei province or their own provinces would be invited to participate in the study by sending the e-questionnaire link to their official WeChat groups. In this step, we invited 23 medical staff  who met our selection criteria. These participants were encouraged to send our e-questionnaire link to acquaintances who met these criteria. To increase the number of participants, all participants were given the chance to draw a random digital red packet on WeChat as the reward, and the distributors would receive an additional bonus. Based on these sampling methods, our link was disseminated quickly via a wide network and participants simply needed to click the link and follow the online prompts to complete the questionnaire.p) of 0.05, 95% power, at least 241 participants were required.The sample size was determined through power analysis and calculated using the G*Power program , 30. WheA total of 360 participants joined our study. All submitted the questionnaire; however, 18 were excluded because they were not a nurse or physician , and 61 were not working in the infectious disease isolation ward of COVID-19 designated hospitals (working in departments such as fever outpatient and wards not for COVID-19 patients)  in these initial tests were then entered into a multiple linear regression models to determine predictors for the levels of hospice care self-efficacy of medical staff fighting against COVID-19.Survey data were exported from Questionnaire Star into the Statistical Package for Social Sciences (SPSS) package , which was used for all data analysis. Descriptive statistics were used to express the sample characteristics and study variables. Differences in the hospice care self-efficacy of participants with different demographics, work motivations in fighting against COVID-19, self-competences in death work, coping strategies and positive aspects of caregiving were assessed using t-tests, or one–way analysis of variance (ANOVA), or the correlation test . Variables identified as being significant (Table Table P = 0.002), professional titles , self-competence in death work , history of providing hospice care for dying or dead patients before fighting against COVID-19 , occupational exposure while fighting against COVID-19 , positive aspects of caregiving , positive coping , negative coping , holding respect for life and professional sentiment  and expectations for the futures  , self-competence in death work , history of having given hospice care for dying or dead patients before fighting against COVID-19 , occupational exposure while fighting against COVID-19 , positive aspects of caregiving , positive coping , and holding respect for life and professional sentiment . The variables co-explained 58.7% of the variation of hospice care self-efficacy , Taoism , and Buddhism  . The traWe found that nurses and physicians with higher self-competence in death work had better hospice care self-efficacy. Self-competence in death work refers to ‘the competence required to cope with the emotional and existential challenges to self in working with death or matters related to death’ . AssessiNurses and physicians who had acquired hospice care experience by giving hospice care for dying or dead patients in a hospital or hospice prior to the COVID-19 pandemic also had better hospice care self-efficacy, as did those from higher-level hospitals. Medical staff might acquire relevant knowledge and skills from their own hospice care experience and then display higher hospice care self-efficacy. Medical staff from level 3 hospitals may have more access to continuous hospice education and may have better knowledge of and attitudes towards hospice care than those from lower level hospitals; this might be beneficial for their hospice care self-efficacy , 49. HowClinical nurses and physicians in the COVID-19 isolation wards of designated hospitals with positive coping and PAC had better hospice care self-efficacy, especially those who respected life, and had strong responsibility and professional ethics. This result was similar to that of Zheng et al. . ResearcBy contrast, medical staff with occupational exposure had lower hospice care self-efficacy in fighting against the COVID-19 pandemic. Health-care workers had high risk of occupational exposure to COVID-19 through intimate contact with patients with confirmed or suspected COVID-19 . MedicalThe present study has some limitations. First, this is a cross-sectional study; therefore, the relationship between self-competence in death work, positive aspects of caregiving, coping strategies, and hospice care self-efficacy cannot be established. Second, based on the purpose of this study, self-reported questionnaires were used to collect the data. These methods are subject to social desirability bias . Third, Nurses and physicians reported a moderate level of hospice care self-efficacy during the COVID-19 pandemic. Hospice care self-efficacy was promoted by better self-competence in death work, effective coping strategies, higher level of positive aspects of caregivers, and experience of hospice care before the COVID-19 pandemic; however, it was reduced by experience of occupational exposure in fighting against the COVID-19 pandemic. Exploring the traditional Chinese philosophy of life to learn from its strengths and make up for its weaknesses and applying it to hospice care may provide a new directions for facing death or dying during the COVID-19 pandemic. Additionally, health systems could carry out continuous hospice care education to promote medical staff’s self-competence in death work by improving their hospice care knowledge and skills. Taking effective measures to mobilize positive psychological resources and providing safer practice environments to avoid occupational exposure are also essential for the improvement of the hospice care self-efficacy of nurses and physicians to effectively deal with death or dying when fighting against the COVID-19 pandemic.


The proposed nanocavities that supported plasmonic gap modes exhibited distinguished properties of nanolasers, such as low-transparency threshold-gain and low lasing threshold. The corresponding experimental results for the MAPbBr3 nanolaser on Ag revealed the low-threshold operation. These superior features were attributed to enhanced light-matter interaction with strong coupling. Therefore, the proposed scheme, integrated with hybrid perovskite as gain material, provides an excellent platform for nanoscale plasmon lasing in the visible to near-infrared spectra.We systematically studied the characteristics of hybrid perovskite-based surface plasmon nanolasers. If one changes the anion composition of perovskites, the emission wavelength can be easily tuned. We conducted in full-spectrum modeling that featured hybrid perovskite nanowires placed on different SiO We compared these estimated values of the Q-factor of the resonance modes in the cavities obtained using three perovskites  on SiO2-coated Ag and Al plates at a fixed gap thickness tg of 7 nm. For fair comparison, cavity length L was set to four effective wavelengths (4λ/ Re[neff]) at the corresponding λ, where Re[neff] is the effective modal index of guided modes in each case. We concluded that because of the large intrinsic material loss of Al in the visible spectrum, the Q-factors of the cavities on Al plates were not comparable to Ag plates. The Q-factor was certainly higher in the cavity at the wavelength λ close to 425 nm. However, it was less capable of confining the hybrid plasmonic mode inside the gain region near the thin gaps, as indicated by the confinement factor. Therefore, the comparison of Q-factors also suggested that Ag is preferred in the perovskite-incorporated plasmonic scheme in the visible spectrum. Therefore, the scattering loss from end facets may not be the dominant factor that degrades the performance of cavities. As indicated by the lowest transparency threshold gains as depicted in the Fig. Q-factor, which indicates potential in future applications related to plasmon-enhanced exciton-photon coupling and bio-sensing.After determining the spatial distribution of modal profiles as shown in Fig. 3 NW on the SiO2-covered Ag plate are presented in Fig. 3 nanolaser. In the emission spectra, the output power dramatically increases at the pumping power higher than the threshold (at approximately 1.62 μW average power); the sharp change was also observed in the corresponding L-L curves as shown in Fig. 3 than that of ZnO and the smaller internal loss at 550 nm than that at 370 nm [Power-dependent photoluminescence was measured to resolve the emission spectra and record the lasing power at various pumping inputs, as displayed in Fig. t 370 nm . Additiot 370 nm –28 reveat 370 nm  and cryst 370 nm  of perov2-coated metallic  plates was conducted. The calculated results using FEM revealed that Ag can be a suitable choice as a plasmonic metal for perovskite MAPbX3-based optoelectronic application. The proposed nanocavity—a MAPbBr3 nanowire on the SiO2/Ag plate, exhibited low lasing threshold and narrow linewidth corresponding to nanoscale output footprint. These advantages can result in strong coupling of exciton-polariton-photons. With the superior charge features possessed by perovskites, this scheme is an appropriate candidate for developing next-generation light sources.Full-spectrum analysis of laser parameters including guided mode characteristics, transparency threshold gains, and estimated quality factor of the perovskite-based nanolasers that featured doped perovskite nanowires placed on three types of SiO


Purpose: To report a study that assesses the influence of the distance between the distal end of a thoracic stent-graft and the first reentry tear (SG-FRT) on the progression of false lumen (FL) thrombosis in patients who underwent thoracic endovascular aortic repair (TEVAR). Materials and Methods: Three patient-specific geometrical models were reconstructed from postoperative computed tomography scans. Two additional models were created by artificially changing the SG-FRT distance in patients 1 and 2. In all 5 models, computational fluid dynamics simulations coupled with thrombus formation modeling were performed at physiological flow conditions. Predicted FL thrombosis was compared to follow-up scans. Results: There was reduced false lumen flow and low time-averaged wall shear stress (TAWSS) in patients with large SG-FRT distances. Predicted thrombus formation and growth were consistent with follow-up scans for all patients. Reducing the SG-FRT distance by 30 mm in patient 1 increased the flow and time-averaged wall shear stress in the upper abdominal FL, reducing the thrombus volume by 9.6%. Increasing the SG-FRT distance in patient 2 resulted in faster thoracic thrombosis and increased total thrombus volume. Conclusion: The location of reentry tears can influence the progression of FL thrombosis following TEVAR. The more distal the reentry tear in the aorta the more likely it is that FL thrombosis will occur. Hence, the distal landing zone of the stent-graft should be chosen carefully to ensure a sufficient SG-FRT distance. It has been reported that roughly 90% of patients with uncomplicated type B dissections will survive to hospital discharge if treated with medical therapy alone.2 Although thoracic endovascular aortic repair (TEVAR) has emerged as a viable option in the treatment of type B dissection, its use was mainly limited to complicated cases to replace high-risk open surgeries.2 However, recent studies have highlighted the efficacy of TEVAR in uncomplicated cases, with a significantly higher number of patients achieving the desired complete thrombosis of the false lumen (FL) following TEVAR.36Aortic dissection affects 3 to 5 of 100,000 individuals every year,8 With the potential for such complications, it is desirable to understand and be able to predict the progression of the disease after TEVAR. This will allow, first, patients to be selected for TEVAR only if there is a high chance of FL thrombosis, and second, clinicians to tailor the TEVAR treatment to each patient individually.While there is evidence suggesting that TEVAR is an effective treatment method for uncomplicated cases, it is still an invasive procedure in which a stent-graft is inserted into the true lumen (TL), covering the primary entry tear to reduce blood flow to the FL and promote thrombosis. This procedure carries risks, which include standard surgical procedural risks and late-onset risks induced by the stent-graft, such as new reentry tears, endoleaks, retrograde dissection, and stent-graft migration, all of which may require further intervention.912 while several anatomical studies1316 have identified morphological parameters of the aorta that influence the progression of the disease. For example, the presence of additional reentry tears was found to reduce the chances of FL thrombosis. Moreover, geometrical features of the stent-graft itself  were analyzed but did not show statistically significant correlations with FL thrombosis.A number of studies have been conducted that provide insight into the thrombosis process post TEVAR. Computational studies have assessed aortic hemodynamics after TEVAR,Stent-grafts are manufactured in set sizes, and given the limited sizing options, it is possible that not all patients are receiving a best fit (in terms of both diameter and length). Additionally, as the primary entry tear is usually the largest, a stent-graft may be chosen with the primary objective of covering this tear, without consideration of further distal tears. Moreover, little work has been done to assess the influence of distal tears and their locations on TEVAR outcome. Therefore, the objective of this study was to investigate how the distance between the distal end of the stent-graft and first post-stent reentry tear may influence FL thrombosis after TEVAR using computational modeling of flow and thrombus formation in patient-specific geometries.4 were included in this study. Formal ethical approval was not required for this retrospective study, as prior agreement was made to undertake computational modeling using anonymized images and data. Computed tomography (CT) scans were acquired within the first month post-TEVAR and annually for up to 3 years. CT scans were performed using the Brilliance 40 , Lightspeed VCT , or Volume Zoom  scanner, with a voxel size range of (0.47–0.77) × (0.47–0.77) × (0.8–1.5) mm3 and a kVp of 120. Patient-specific geometries were reconstructed from CT scans using Mimics  based on a semiautomated, threshold-based algorithm. Manual refinement was performed in order to separate the region of interest from the surroundings. For each reconstructed model, the false lumen volume was calculated by using the following expression:Three patients  treated with TEVAR using a Gore TAG device  in the acute phase for uncomplicated type B aortic dissection as part of the ADSORB triali,FLS is the cross-sectional area of the FL for each axial slice i, N is the total number of axial slices, and h is the slice thickness. The FL was present only in the descending aorta, distal to the left subclavian artery, for all patients. Percentage changes in FL volume between the first and 1-year follow-up scans were calculated, as not all patients had follow-up imaging beyond 1 year.where In each reconstructed model, the distance between the distal end of the stent-graft and first post-stent reentry tear (SG-FRT) was measured along the centerline, which was fit using an automatic function in Mimics. To investigate the role of the SG-FRT distance, additional models were created. In the first post-TEVAR scan of P1, the FRT  was artificially moved upward by 30 mm toward the stent. In the first post-TEVAR scan of P2, two post-stent tears close to the distal end of the stent-graft were occluded to simulate the extension of the stent-graft by 30 mm. 17 was applied in all models. Since the 3-element windkessel model was recommended as the most appropriate outlet boundary condition,18 this was applied at each outlet with the relevant parameters taken from the literature.17 All flow simulations were performed using Ansys CFX . A fixed time step of 0.005 seconds was chosen based on previous sensitivity tests, and each model was simulated for 4 cardiac cycles to ensure a periodic solution. Results from the last cardiac cycle were used to initialize the thrombosis model.The 5 geometrical models were imported into ICEM CFD software  and discretized into unstructured meshes consisting of 5 to 10 million elements each. Mesh sensitivity tests were carried out for all models to ensure mesh-independent solutions. In order to focus on the influence of the SG-FRT distance on FL thrombosis, the same pulsatile inlet flow waveform20 was implemented. A time step of 0.005 seconds was used, and simulations were run until there were no further changes in predicted thrombus patterns. The number of cardiac cycles required varied between models: 20 cycles for P1 and P1-mod, 22 for P2 and P2-mod, and 20 for P3. For P2, two intercostal arteries were present in line with the 2 upper thoracic tears, meaning that flow from the true lumen would be diverted to these arteries as well as through the 2 tears. As the intercostal arteries were too small to segment from the CT scan, they were excluded from the computational model, resulting in artificially increased flow through the tears and thus higher time-averaged wall shear stress (TAWSS). TAWSS is a key parameter on which the coagulant flux boundary condition in the thrombosis model is dependent; therefore, a modified coagulant flux boundary condition from a previous study20 was applied in this region for P2. This condition gives a constant coagulant production balanced by coagulant consumption dependent on time-averaged shear rates.To simulate thrombus formation and growth over time, the shear-driven thrombosis model developed and validated in the previous work of Menichini et alPredicted thrombus patterns were validated against the actual thrombus formation observed from follow-up scans. Additionally, comparisons were made between the original and modified models to assess the influence of SG-FRT distance on FL thrombosis.Percentage changes in the FL volume between the first post-TEVAR and 1-year follow-up scans are reported in For P2-mod, covering the 2 proximal entry tears drastically altered the FL hemodynamics. There was no flow in the upper thoracic FL, resulting in very low TAWSS in this region. Additionally, the average TAWSS in the abdominal FL decreased slightly (0.52 Pa compared with 0.55 Pa in P2). The amount of flow entering the FL-perfused left renal artery was calculated, and very little change was observed between the original and modified geometries.The predicted thrombus growth patterns for the original models are shown in Comparisons with follow-up scans revealed a good overall agreement between the predicted thrombus growth and actual clinical observations. The model was able to capture the location of thrombus growth and correctly predict incomplete thrombosis within a simulated time frame of 30 seconds. Some disagreements can be observed in P1 and P2. In P1  compared with P2, initially suggesting that the SG-FRT distance may be a key parameter in determining FL flow and thus FL thrombosis. In order to investigate this parameter while keeping all other morphological parameters constant, modifications were made to P1 and P2. The reduction of the SG-FRT distance in P1, by moving the FRT proximally by 30 mm, resulted in increased FL flow and TAWSS in the region adjacent to the tear and reduced FL thrombosis. The occurrence of a stent-graft–induced new entry tear (SINE) would also drastically decrease the SG-FRT distance. The detrimental influence of SINE on FL thrombosis and aortic remodeling has been highlighted in the literature and is in line with the results of this study showing that a decrease in SG-FRT reduces FL thrombosis.24 This should be considered when choosing the stent-graft length, and the desire to cover additional tears should be balanced with the increased risk of such a complication. In the case where a longer stent-graft is used to occlude additional reentry tears, reducing the stent-graft length to increase the SG-FRT distance would cause the most distal covered reentry tear to be exposed, resetting the SG-FRT to zero. Therefore, in this scenario, artificially increasing the SG-FRT distance by decreasing stent-graft length would not benefit FL thrombosis.Increasing the SG-FRT distance in P2 by artificially extending the stent-graft 30 mm to cover the 2 adjacent reentry tears led to reduced FL flow and TAWSS, as well as faster and increased FL thrombosis. These results indicate that a large distance between the distal end of the stent-graft and the FRT would be favorable for FL thrombosis. Additionally, it was shown that occluding these tears by extension of the stent-graft had little impact on the flow to the FL-perfused left renal artery. This means a longer stent-graft could have been used for this patient without adversely affecting left renal artery perfusion. In this case the extension of the stent-graft was by only 30 mm, with 100 mm between the distal end of the stent-graft and the celiac trunk remaining uncovered. However, it has been highlighted that extended coverage of the entire thoracic aorta up to the celiac trunk may be linked to an increased risk of spinal cord ischemia.11 the model complexity was increased to include major side branches. Consistency between simulated thrombus formation and follow-up CT scans further demonstrated the validity of the predictive model. Slight deviations in results were mainly attributed to the presence of minor FL-perfused branches. In regions where small branches were artificially occluded, the model overpredicted thrombus formation. This is due to the fact that the presence of FL branches creates an additional pressure drop that drives flow within the FL and hinders the deposition of platelets and the formation of thrombus. This factor has been highlighted in several anatomical studies for both TEVAR and medical management patients.1316Following on the previous work of predicting FL thrombosis in TEVAR patients,Although much work has been done to identify the effects of changing morphological features on the presence of FL thrombosis after TEVAR, little had been done prior to this work to quantify thrombus formation and assess the direct effect of such parameters on changes in FL volume, especially looking at specific regions of the aorta. Our aim was to understand the physics behind key morphological parameters related to both the patient and the stent-graft. While there are numerous biological and morphological factors that contribute to FL thrombosis after TEVAR, the focus of this study on one specific parameter highlights the significant influence that a single variable can have on patient outcome. It is hoped that these findings will help us elucidate the dynamics driving the progression of type B aortic dissection for endovascularly treated patients, which will further help clinicians develop more effective treatment strategies for individual patients.The work presented here has several limitations. First, the number of patients included was small. Dissections can present in a wide range of morphologies and analysis of a larger cohort would provide the opportunity to study morphological parameters in varied cases. Second, all patients included in the present study were treated with a GORE TAG device in the TEVAR procedure. It would be necessary to extend the study to patients treated with different devices in order to elucidate the effect of stent-graft design on the predicted outcome.20 and the results from this study show good agreement between model predictions and follow-up scans, there is room for further refinement. The patient-specific computational models did not include minor side branches , and our results showed that excluding such branches could influence the predicted thrombus formation.With regard to the computational model, while previous work has validated the thrombosis model for predicting clinical outcomes,25 which could affect predictions of flow and thrombus growth in dissected regions not covered by the stent-graft. Furthermore, the inflexibility of the stent-graft and its relative stiffness compared to the aortic wall may impact aortic hemodynamics and thrombus formation.Additionally, all models in this study assumed rigid wall behavior. It is known that the intimal flap is initially mobile and becomes stiffer as the dissection progresses to the chronic phase,Our results demonstrate that the SG-FRT distance can influence FL hemodynamics and thrombus formation, with a large SG-FRT favoring FL thrombosis. These findings could potentially help clinicians select the most appropriate treatments for individual patients and to predict which patients would be most likely to benefit from endovascular treatments. Future studies of a larger cohort of patients will be beneficial to assess the impact of SG-FRT distance on a wide range of dissection morphologies. Additionally, further studies using our methodology of modifying patient-specific geometries will facilitate similar analysis of other key morphological parameters to determine which anatomical factors play the most important role in the progression of aortic dissection.


Despite considerable efforts to control tuberculosis (TB) among Ethiopian immigrants in Israel, an outbreak of TB among second-generation Ethiopian immigrants that involved native Israelis occurred between January 2011 and December 2019. The aim of this article is to report on this outbreak and discuss the patient and health system barriers that led to its propagation. Overall, 13 culture-positive TB patients were diagnosed in this outbreak. An additional 36 cases with identical mycobacterium tuberculosis genotypes were identified through cross-checking with the National TB Laboratory Registry. Among the 32 close contacts of the index case, 18 (56.3%) reported for screening and treatment of latent TB infection (LTBI) was recommended for 11 (61.1%) of them. However, none completed treatment and eight eventually developed TB. Of the 385 close contacts identified in this outbreak, 286 (74.3%) underwent contact investigation, 154 (53.8%) were recommended LTBI treatment, but only 26 (16.9%) completed the treatment. Routine contact investigation and treatment practice measures failed to contain the cascade of infection and disease, leading to the spread of the infecting strain of TB. This report highlights the challenges to identify the high-risk group and address barriers to care among such a vulnerable population. During the last three decades, Ethiopians of Jewish descent immigrated to Israel and subsequently, the second generation of Jewish Ethiopian descendants were born in Israel.Ethiopian immigrants (EI's) have to undergo screening for active tuberculosis (TB) and latent TB infection (LTBI) while in Ethiopia before their departure to Israel. The screening consists of a tuberculin skin test (TST) and chest X-ray. Those with a positive TST or abnormal chest X-ray are referred upon arrival in Israel to one of the TB clinics for further evaluation and treatment. It is worth noting that all TB-related medical care in Israel is provided exclusively in nine specialist centres (TB clinics) dispersed across the country .This report describes an outbreak of TB among second-generation Ethiopians during 2011–2019, which expanded to involve native Israelis as well. The outbreak started with the diagnosis of the index case in January 2011. The index case was a 20-years-old male, Israeli-born EI descendant. He sought medical care for cough and fatigue that had continued for 4 months. He had smear-positive, culture-positive, bilateral pulmonary TB susceptible to first-line treatment medications. He also had a history of alcohol and illicit substance abuse. Due to his poor condition and slow sputum conversion, he was hospitalised for 3 months in a TB ward. The most recent case was a 17-year-old, a close contact of an active TB patient in this outbreak, diagnosed in December 2019.The aim of this report is to describe the clinical and epidemiologic characteristics of this outbreak and contributing factors for poor compliance to LTBI treatment and to discuss the barriers at the patient and health system levels, particularly for high-risk and vulnerable groups.Culture-positive TB cases closely related to this group and with isolates matching the outbreak strain by genotyping were defined as part of this outbreak.Patients with identical mycobacterium tuberculosis genotypes not closely related to the outbreak, who were identified through cross-matching to the National TB laboratory registry, were defined as part of this cluster.M. tuberculosis isolates were characterised by the National Mycobacterium Reference Laboratory as previously reported [The species identification was performed by a commercial strip DNA probe test . All reported .The contacts underwent standard contact investigation as described previously . They unThe index case had 32 reported close contacts; five were family members, nine co-workers and 18 friends. He used to meet with his friends in a small basement, where they engaged in smoking illicit substances and drinking alcohol. Only 18 (56.2%) of his close contacts reported for screening; 11 (61.1%) had LTBI and none completed LTBI treatment . During Of the 385 contacts identified in this outbreak, 286 (74.3%) underwent contact investigation, 154 (53.8%) had a positive TST and 135 (87.7%) started LTBI treatment, however, only 26 (16.9%) completed treatment.M. tuberculosis strain known as Clade T1 SIT 926 .All 13 culture-positive cases were infected with an identical By cross-matching to the National Israeli TB laboratory registry, we identified an additional 36 culture-positive TB cases nationwide infected with this strain. Of those additional 36 culture-positive TB cases infected with this strain nationwide, 33 cases involved first and second-generation immigrants from Ethiopia. The first cases in this cluster were diagnosed in 1998 during a TB outbreak at a boarding school with six culture-positive TB cases among EI in that outbreak [Despite the high treatment initiation rate among TB contacts in this outbreak, only 16.9% eventually completed treatment. This poor outcome led to a cascade of infection and disease that lasted for 9 years.The current incidence of TB among native Israelis is low (1.0 per 100 000 person-years) and most TB patients are foreign-born . NeverthWe have previously reported high LTBI treatment completion rates 94%) among Ethiopian immigrants in Israel, with directly observed isoniazid treatment and free transportation provided % among E, 4.There were several barriers to health care, at both the patient and system levels, that may have caused such poor treatment adherence in this outbreak. At the patient level, attending clinic appointments posed challenges, such as the cost and inconvenience of commuting to and from the clinic. Commuting to the TB clinic from the provincial areas of the northern district was challenging for contacts without private transportation. Many of those who missed their follow-up appointment at the TB clinic, declined to return because of the inconvenience of public transportation to the TB clinic. Some individuals involved in this outbreak were unemployed or were employed at low wages. Poverty and financial hardships have been associated with poor treatment adherence . For thoFurthermore, awareness of the possibility of TST cross-reaction with a previous BCG vaccination deterred many contacts from accepting TST ‘positive’ results as indicative of infection . PatientAll 10 male SGE contacts who developed TB in this outbreak abused alcohol or smoked illicit substances. Such high-risk behaviour has been reported among the youth of immigrant population . UnemploApart from the barriers to treatment at the patient level described above, there were barriers at a system-level as well. National TB control programmes (NTP) are usually focused on finding and treating active TB. In Israel, the programme grants active TB patients (as well as recent EI's), monetary incentives during the treatment phase. These interventions likely promoted patient compliance , 4. MoneWith hindsight, this outbreak could have been anticipated. The poor response to the call to be present for the screening and the low adherence to LTBI treatment should have alerted the health care professionals overseeing this outbreak to the risk of evolution of latent TB cases to active disease.This ongoing TB transmission among second-generation immigrants raised our awareness regarding the need for a proper definition, identification and management of high-risk groups with obstacles to health care. This outbreak illustrates the increased risk for TB transmission among second-generation immigrants, not formally defined as a high-risk group and the need to recognise and act upon the specific obstacles to health care facing this community. Routine contact investigation practices in this outbreak fell short of stopping the cascade of TB transmission and disease, which lasted for 9 years.This report describes an ongoing transmission of TB involving second-generation immigrants, which eventually spread to native Israelis. It illustrates the need to recognise and act upon the barriers to health care facing this population. It also raises the issue of defining the high-risk group and the rationale to include second-generation immigrants from high endemic countries. We suggest that individuals with financial hardships or with high-risk behaviour be included so that they would be offered a personalised treatment approach that addresses their health care obstacles and their special needs.


The usability of laboratory tests related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critically important for the world undergoing the COVID-19 pandemic. The present study aimed to assess the diagnostic usability of rapid tests for the detection of antibody against SARS-CoV-2 through comparison of their results with the results of reverse transcription polymerase chain reaction (RT-PCR) test for the detection of SARS-CoV-2 genomic RNA and with the results of a quantitative test for antibody detection.Serum samples were collected from 18 patients undergoing RT-PCR testing for SARS-CoV-2. Twelve patients were RT-PCR positive while six were negative. A quantitative test based on chemiluminescent immunoassay and three rapid tests based on immunochromatography were performed to detect anti-SARS-CoV-2 IgG and IgM.All the antibody tests exhibited poor sensitivity at the timing of initial RT-PCR diagnosis. IgG responses occurring prior to or simultaneously with IgM responses were observed through not only the quantitative test but also the three rapid tests. Based on concordance with the quantitative test results, the large variance among the three rapid tests was revealed.All antibody tests were unsatisfactory to replace RT-PCR for the early diagnosis of COVID-19. Rapid antibody tests as well as a quantitative antibody test were useful in the assessment of immune responses in COVID-19. The obvious variance among the three rapid tests suggested limited accuracy and difficult standardization. Diagnostic usability of rapid antibody tests for COVID-19 should be investigated rigorously. COVID-19, an infectious disease due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is mainly diagnosed through viral RNA detection by reverse transcription polymerase chain reaction (RT-PCR) testing of nasal or pharyngeal swabs, saliva, or sputum. RT-PCR tests require equipment, reagents and well-trained medical technologists. The availability of such resources is limited. In addition, sampling of nasal or pharyngeal swabs may run the risk of exposing medical staff to viruses.2 However, the usability of rapid tests for antibody detection as early diagnostic methods remains to be ascertained. In order to ascertain whether rapid antibody tests substitute for RT-PCR tests, we assessed the diagnostic usability of several commercially available rapid antibody tests using the serum samples obtained at the timing of RT-PCR diagnosis. We also evaluated their accuracy according to concordance with a quantitative test for IgG and IgM specific to SARS-CoV-2 as the standard reference.In contrast, rapid antibody tests to detect blood, plasma or serum IgG and IgM specific to SARS-CoV-2 require neither special equipment nor training. Turnaround time is far shorter than RT-PCR tests. Several reports demonstrated high diagnostic accuracy of rapid antibody tests by comparing them with RT-PCR tests using samples from hospitalized patients who were already diagnosed as COVID-19 according to RT-PCR test results.The present study was performed under the approval by the Ethics Committee of Keio University School of Medicine .Serum samples for the present study were collected from 18 patients undergoing RT-PCR testing for SARS-CoV-2 at Keio University Hospital . Twelve patients were RT-PCR positive while six were negative. One-Step Real-Time RT-PCR assays were performed using BD MAX with BD MAX TNA MMK and BD MAX ExK TNA-3 . The primers and the probes specific to SARS-CoV-2 N1 and N2 were used for RT-PCR. The RT-PCR positivity was defined as threshold cycle (Ct) values being less than 45 cycles.Serum samples, which were collected from the patients on the day of RT-PCR using nasopharyngeal specimens or on the day before or after the testing, were used for their laboratory tests. After the performance of tests, the residual serum of each patient was subjected to evaluation of the usability of antibody tests as early diagnostic methods, for which RT-PCR results were used as the standard reference regarding COVID-19 diagnosis. In addition, the residuals of serum samples serially collected from RT-PCR positive patients at various time points within three weeks after the RT-PCR performance were subjected to evaluation of the accuracy of rapid antibody tests according to concordance with the quantitative antibody test.The rapid tests for the detection of IgG and IgM specific to SARS-CoV-2 were done using ALLTest 2019-nCoV IgG/IgM Rapid Test Cassette (ALLTest) , STANDARD Q COVID-19 IgM/IgG Duo Test (SD Biosensor)  and Kurabo Rapid immunochromatographic test for detecting the antibody of SARS-CoV-2 (KURABO) . These three kits are based on immunochromatography.A qualitative antibody test based on chemiluminescence immunoassay was done using the iFLASH Immunoassay Analyzer and the SARS-CoV-2 IgG and IgM reagents (iFLASH) . With respect to IgG and IgM, the titre of 10 AU/mL was the cut-off value to distinguish positivity and negativity.Age, sex and results of rapid antibody tests and a quantitative antibody test were subjected to comparison between RT-PCR positive and negative patients . Fisher’For RT-PCR positive patients, severity of COVID-19 , Ct values of RT-PCR for SARS-CoV-2 N1 and N2 and days from the onset to the sampling were summarized. The onset date was basically defined as the date on which symptoms  or chest imaging findings compatible with COVID-19 such as bilateral ground glass opacity in chest computed tomography (CT) appeared. In the case of asymptomatic patients, the onset date was instead defined as the date on which RT-PCR positivity was confirmed.P value < 0.05 was considered significant.The numbers of positivity and negativity regarding antibody test results using the residuals of serum samples serially collected from PCR positive patients were summarized for each day after the onset for assessing seroconversion. In order to compare the accuracy among rapid antibody test kits, concordance rates, sensitivity, specificity, positive predictive values and negative predictive values were evaluated using quantitative antibody test results. Kappa coefficients were calculated to measure concordance. The threshold antibody titres defined as the minimum quantitative antibody titres in which both the quantitative antibody test and each rapid antibody test exhibit positivity were detected. The rates of occurrence of positive results of rapid antibody tests over the threshold antibody titres were calculated. For statistical analysis, SPSS 25  was used, and a Of 12 RT-PCR positive patients, 7 had mild symptoms, 2 had moderate symptoms, and 1 had severe symptoms at the timing of diagnostic PCR performance . Two asyAll samples exhibiting the positivity were collected after six days or more since the onset .k = 0.93). Regarding detection of anti-SARS-CoV-2 IgM, statistical significance was observed in SD BIOSENSOR and KURABO kits but not in ALLTest kit. SD BIOSENSOR kit exhibited the highest concordance with the quantitative test (k = 0.76). Overall, the accuracy of anti-SARS-CoV-2 IgM tests was apparently lower than that of anti-SARS-CoV-2 IgG.Regarding detection of anti-SARS-CoV-2 IgG, statistical significance was observed in all three rapid test kits using the quantitative test results as the standard reference . SD BIOS3 Although rapid tests are expected to overcome such concerns, their accuracy seemingly varies by manufacturers. The present study aimed to assess the diagnostic performance and accuracy of immunochromatography-based rapid test kits for antibody detection through comparison with RT-PCR for SARS-CoV-2 as well as with chemiluminescent immunoassay-based quantitative analysis of antibodies.PCR-based methods for SARS-CoV-2 detection are not only inapplicable to point of care testing because of requiring specialized instruments, labour and time but also are known to have variation in false-negative rate by time since exposure.4 In contrast, both the rapid tests and the quantitative test exhibited poor sensitivity at the timing of initial RT-PCR diagnosis in the present study. Antibodies became detectable in about eight days after the onset. These observations are consistent with previous reports demonstrating that antibody test positivity proved COVID-19 occurrence in the middle or late stage of the disease.6 In addition, it has been reported that use of antibody tests without RT-PCR tests in a first week of symptomatic phase, in which the higher rate of viral shedding is observed than in the later phase, results in failure to make diagnosis of COVID-19.7Zhao et al. reported antibody detection one day after the symptom onset by ELISA kit targeting at S1 protein.9 Consistent with these reports, IgG responses occurring prior to or simultaneously with IgM responses were observed through not only the quantitative test but also the rapid tests in the present study. There are at least two possibilities to explain such responses. One is reinfection or primary infection with SARS-CoV-2 following prior infection with other coronaviruses to lead to cross-reactive immune. Another possibility is non-canonical immune responses to primary viral infection, which may reportedly occur independently of germinal centre formation in peripheral lymphoid organs.11 In this case, a time length resulting from the occurrence of canonical class-switch from IgM to IgG in germinal centres is absent. IgG responses might be allowed to appear prior to or simultaneously with IgM responses.The unique antibody responses to SARS-CoV-2, such as IgM seroconversion not preceding IgG seroconversion, have been reported in previous studies.12 The accuracy of IgM tests totally seemed to be lower than that of IgG tests. Rheumatoid factor existing in serum IgM is known to interfere with immunological assays via binding to the IgG Fc portion.13 IgM also contains natural antibodies reactive to various substances, which may bind to the components of the test kits to interfere with the assay.14 These mechanisms might be related to the difference in the accuracy between IgG and IgM tests.Comparison with the quantitative test revealed the variance of the rapid antibody tests to allow us to recognize their limited accuracy and difficult standardization. Despite the fact that all the three rapid tests target SARS-CoV-2 nucleocapsid protein, the SD Biosensor IgG test exhibited great concordance with the quantitative test while the ALLTest IgM test exhibited poor concordance. The poor sensitivity of ALLTest kits has also been reported in a previous study.16 The large variance regarding the concordance with the quantitative antibody test leads us to consider about how best to deal with data that are collected using various rapid tests. While the present study focused on diagnostic application of rapid antibody tests for COVID-19, epidemiological application to assessment of herd immunity against SARS-CoV-2 infection is also of critical importance.While a number of studies evaluating rapid antibody tests for the detection of SARS-CoV-2 infection have been published, the advantage of the present study is to compare results of the various rapid antibody tests not only with results of the PCR test but also with results of the quantitative antibody test to reveal the limited accuracy and difficult standardization. This would lead to additional impact on the understanding of the diagnostic potential of rapid antibody tests.17Although the true negative results and the cumulative positive conversion rate are shown in 18 This suggests that there are no differences in false positivity between the SD Biosensor and the ALLTest.While the SD Biosensor seemed to be better at detecting anti-SARS-CoV-2 IgM than the ALLTest according to the results, it remains to be assessed whether the SD Biosensor had higher false positivity in the present study. In a recent study, the specificity for the SD Biosensor-IgG and the specificity for the Alltest-IgG were both 99.0% while that for the SD Biosensor-IgM and that for the Alltest-IgM were both 98.0%.14 Rheumatoid factors may also give rise to overestimation or underestimation of immunoassays.13 It is plausible that such interference is expected to result in the difference in the results among various rapid antibody tests. However, it is difficult to address what is the cause of the difference because the details of the components of each kit have not yet been disclosed.As described above, natural antibodies contained in the IgM fraction might react to some impurities potentially existing in kits to interfere with immunoassays.1820As observed in the present study, the recent studies have suggested that IgM tests for detecting SARS-CoV-2 infection exhibit low reliability because of large variance among various kits as well as insufficient specificity or sensitivity. On the other hand, IgG tests seem to be more reliable because of small variance as well as higher specificity and sensitivity.While the merit of the present study lies in effective estimation of multiple serodiagnostics using a minimum number of clinical subjects, it also, in turn, reflect the limitations of the present study including imprecise estimates due to heterogeneity in the timing for sampling at which results were obtained, as well as a small number of patients and samples. To address the concerns, basic, laboratory and epidemiological findings should be accumulated relevantly to diagnostics and therapeutics.In conclusion, all antibody tests were unsatisfactory to replace RT-PCR for SARS-CoV-2 as early diagnostic methods while being useful in the assessment of immune responses in COVID-19. Diagnostic usability of rapid antibody tests should be investigated rigorously in consideration of their variance.Click here for additional data file.Supplemental material, sj-pdf-1-acb-10.1177_0004563220984827 for Evaluation of the usability of various rapid antibody tests in the diagnostic application for COVID-19 by Yoshifumi Uwamino, Masatoshi Wakui, Wataru Aoki, Toshinobu Kurafuji, Emmy Yanagita, Maasa Morita, Mika Nagata, Rika Inose, Masayo Noguchi, Hiromitsu Yokota, Naoki Hasegawa, Hideyuki Saya, Mitsuru Murata and for the Keio Donner Project Team in Annals of Clinical BiochemistryClick here for additional data file.Supplemental material, sj-pdf-2-acb-10.1177_0004563220984827 for Evaluation of the usability of various rapid antibody tests in the diagnostic application for COVID-19 by Yoshifumi Uwamino, Masatoshi Wakui, Wataru Aoki, Toshinobu Kurafuji, Emmy Yanagita, Maasa Morita, Mika Nagata, Rika Inose, Masayo Noguchi, Hiromitsu Yokota, Naoki Hasegawa, Hideyuki Saya, Mitsuru Murata and for the Keio Donner Project Team in Annals of Clinical Biochemistry


The need for timely establishment of diagnostic assays arose when Germany was confronted with the first travel-associated outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Europe. We describe our laboratory experiences during a large contact tracing investigation, comparing previously published real-time RT-PCR assays in different PCR systems and a commercial kit. We found that assay performance using the same primers and probes with different PCR systems varied and the commercial kit performed well.  At the end of December 2019, an outbreak caused by a novel coronavirus was announced in Wuhan, China. Since then, the number of cases has increased, especially in China but also in other countries, and public health authorities are in need to rapidly implement diagnostic tools. In this paper, we describe our laboratory experiences with the novel real-time RT-PCR assays comparing different one-step PCR systems and a commercial kit, using a Bio-Rad CFX 96 cycler.In connection with the ongoing outbreak of a novel coronavirus in the province Hubei and surrounding areas in China, it was expected that Europe would also be confronted with the emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as infections in travellers in several Asian countries outside of China were confirmed shortly after the announcement of the outbreak in Wuhan -4. ThereAs soon as the World Health Organization (WHO) published the first protocols for real-time RT-PCR assays, the Bavarian Food and Health Authority started to implement them. We ordered control material and oligonucleotides (see details below) in week 4 and ran our first SARS-CoV-2 assays on 27 January (week 5). On the same day, the first German case of coronavirus disease 2019 (COVID-19) was diagnosed in Bavaria [We initially used the protocol based on the E gene and RdRp gene developed by the German Consiliary Laboratory for Coronaviruses hosted at the Charité in Berlin . Real-tiEach sample was tested by three PCRs: the screening assay for the E gene and two confirmatory assays targeting the RdRp gene, all performed as recommended in , with eiThe cumulative numbers of all tested samples are shown in During the 2 weeks after the first PCR test on 27 January, a rapidly increasing number of case contacts in Bavaria was identified and their respiratory samples were tested. We found that the SARS-CoV E gene screening assay with the QuantiTect Virus +Rox Vial kit showed moderate to high amounts of unspecific signals in late cycles in 61% (451/743) of the tested patient samples and also of negative extraction and non-template controls , which cThree additional one-step real-time PCR systems were compared with the initially used QuantiTect Virus +Rox Vial kit (QIAGEN) : (i) OneIn the following, we decided to switch to the SuperScript III system as recommended by Corman et al. , also beFor evaluation of assay performance regarding efficiency, linearity and unspecific signals, we used the SuperScript protocol in a direct comparison of 73 samples with the RealStar SARS-CoV-2 assay. The E gene assays showed 97% (71/73) identical results in both assays . The specific SARS-CoV-2 assays gave in 67 (92%) identical results (60 negative and seven positive) and six divergent results. Overall, the RealStar SARS-CoV-2 kit seemed to be more sensitive. With increasing sample numbers, it is crucial to implement a new assay into routine laboratory workflows that already exist for diagnostic testing of other pathogens. Sample preparation and RNA extraction were carried out at BSL2 level under a safety class 2 cabinet wearing FFP3 filter masks following the WHO recommendations . SamplesOn 7 January 2020, a novel coronavirus was identified and shortly after, the first sequence of the new strain was published ,10. The National and local public health laboratories play a crucial role in testing emerging pathogens. The Public Health Microbiology Laboratory in Bavaria was confronted with SARS-CoV-2-related events very early: once the assays and control materials arrived and the PCR assays were performed for the first time, a large contact investigation around the first German COVID-19 patient (data not shown) was immediately started, with so far more than 700 samples. Evaluation and verification of the new assays and testing real samples had to take place simultaneously within a very short time. We realised soon that the SARS-CoV E gene assay was more sensitive than the two RdRp gene assays combined with the one-step RT-PCR system available in our laboratory. However, our E gene assay showed high background levels hampering a clear evaluation of the assays. Each mastermix has its own proprietary composition, which may explain the differences in the performance of a certain PCR assay. Using commercial kits with optimised target regions and primer sequences (in the E gene and SARS-CoV-2-specific S gene) ruled out the unspecific signals completely. Hence, reasons for the observed unspecific signals may be dimerisation of primers and probes and/or unspecific primer binding and polymerase activity in the targeted region of the E gene, probably also depending on thermal profile and cycler-specific differences, or most likely a combination of these factors.Contamination as a reason for unspecific signals was ruled out, as stringent prevention measures were taken, e.g. strict separation of working areas: oligonucleotides and PCR mastermix reagents were handled in one room under a PCR hood with specified laboratory coats. Sample preparation and RNA extraction took place in a second room. Sample RNA was added in a third room under a PCR hood. The synthetic E gene control was added last to the mastermix. All reagents were aliquoted and aliquots used once only. Contaminations from synthetic E gene present in primer batches upon delivery can be ruled out as well, although only one batch of E gene primers and probes was used with the QuantiTect and Superscript III setup, as only a certain proportion of samples showed the unspecific signals. Furthermore, the unspecific signals were significantly reduced in the Superscript III setup, which showed that its sensitivity was comparable to the QuantiTect setup. In addition, the initially used E gene primers and probe were separately used as templates with the RealStar kit and no amplification was observed, whereas the corresponding artificial E gene template delivered a clear S-shaped curve with this kit.The SARS-CoV-2 assay from Corman et al.  could be


The outbreak of coronavirus disease 2019 (known as COVID-19), which started in Wuhan, China in December 2019, is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has been associated with both venous and arterial thromboembolism likely secondary to significant cytokine activation and inflammation. Reports on the incidence of thrombotic complications, however, are not well documented. Our case will examine a young man diagnosed with COVID-19 who developed an acute, severe bilateral saddle pulmonary embolism while on prophylactic dose anticoagulation after being admitted to the hospital and treated for two weeks with significant improvement. The novel coronavirus disease 2019 (COVID-19) is a viral illness caused by a virus belongs to a single-stranded ribonucleic acid (RNA) virus of the human coronavirus family, named for the crown-like protein spikes on their surface. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmitted via respiratory droplets is thought to attach to various cell types expressing angiotensin-converting enzyme 2 receptors (ACE2) on their surfaces like in lung alveolar cells, cardiac myocytes, the vascular endothelium, and other cells [The presentation of this illness in patients admitted to the hospital varies significantly in severity. Patients may present with a number of complications, including arrhythmia, septic shock, acute respiratory distress syndrome (ARDS), and multiorgan failure. Due to elevated markers of coagulation identified in patients admitted with COVID-19, the mainstay of treatment is initiating therapeutic anticoagulation . TherapeOur patient is a 29-year-old man with mild, level 1 autism spectrum disorder, who was admitted to the hospital three days after the onset of fever and cough. He was initially treated with broad-spectrum antibiotics, as well as azithromycin and hydroxychloroquine for possible aspiration pneumonia and positive COVID-19 infection. On hospital day 12, the patient showed significant improvement of his overall symptoms. He was scheduled to be discharged in the next two days. That morning, however, a rapid response was called due to the development of acute, worsening dyspnea, and hypotension, requiring immediate intubation, mechanical ventilation, and transfer to the critical care unit. Norepinephrine and phenylephrine were added to his treatment as well due to worsening shock. The patient was restarted on broad-spectrum antibiotics and treated for septic shock and ARDS due to COVID-19 presumably complicated by a bacterial superinfection. During the course of his ICU stay, an elevated D-dimer level was observed at more than 5,000 ng/mL. The patient was switched from prophylactic anticoagulation to therapeutic anticoagulation regimen with a heparin drip due to concern for hypercoagulable state with COVID-19 on day 13. Imaging with CT angiography was performed due to further deterioration of respiratory status on day 14, which confirmed a bilateral saddle PE despite prophylactic anticoagulation  of coagulation complications highlights the benefits of transitioning patients from prophylactic to therapeutic anticoagulation early on in their hospitalization . Our patHowever, despite the new data showing high incidence of thromboembolic events in COVID-19 patients on therapeutic doses, there is still evidence of lower incidence of PE and VTE at therapeutic dose anticoagulation compared to prophylactic doses .There continues to be a need for additional data for anticoagulation in COVID-19 patients. In the meantime, a careful risk stratification strategy can be implemented on case bases to prevent development of PE and VTE in this population even though recent studies have shown high incidence of thromboembolic events with therapeutic doses. Due to the hypercoagulable state of COVID-19 infected patients, early management with anticoagulation is crucial for hospitalized patients in reducing mortality. Standard prophylactic anticoagulation is not sufficient in preventing thrombotic complications. Literature recommends switching standard prophylactic anticoagulation to therapeutic anticoagulation to mitigate microvascular and macrovascular complications. In patients who suddenly and unexpectedly deteriorate, clinical suspicion of a severe coagulopathic event should be high on the differential. This is clearly shown by the hospitalization course of our patient. As clinicians, we need to have a very low threshold when it comes to transitioning COVID-19 infected patients from prophylactic anticoagulation to full-dose therapeutic anticoagulation.


Objective: To identify a multi-gene prognostic factor in patients with lung adenocarcinoma (LUAD).Materials and methods Prognosis-related genes were screened in the TCGA-LUAD cohort. Then, patients in this cohort were randomly separated into training set and test set. Least absolute shrinkage and selection operator (LASSO) regression was performed to the penalized the Cox proportional hazards regression (CPH) model on the training set, and a prognostication combination based on the result of LASSO analysis was developed. By performing Kaplan-Meier curve analysis, univariate and multivariable CPH model on the overall survival (OS) as well as recurrence free survival (RFS), the prognostication performance of the multigene combination were evaluated. Moreover, we constructed a nomogram and performed decision curve analysis to evaluate the clinical application of the multigene combination.Results We obtained 99 prognosis-related genes and screened out a 4-gene combination  according to the LASSO analysis. The results of survival analyses suggested that patients in the 4-gene combination low-risk group had better OS and RFS than those in the 4-gene combination high-risk group. The 4-gene mentioned was demonstrated to be independent prognostic factor of patients with LUAD in the training set and test set . More importantly, its prognosis performance was well in the validation set .Conclusions We introduced a 4-gene combination which could predict the survival of LUAD patients and might be an independent prognostic factor in LUAD. Lung cancer represents the lion's share of cancer morbidity and mortality worldwide, with 2.1 million new lung cancer cases and 1.8 million deaths in 2018, or nearly 1 in 5 18.4%) of the total cancer mortality% of the https://xenabrowser.net/datapages/). The matched clinical data was also obtained from GDC Xena Hub (https://gdc.xenahubs.net). Patients in the TCGA-LUAD including 503 LUAD samples were included in the presents according to the following inclusion criteria: patients with primary lung adenocarcinoma; patients whose survival information was documented; patients whose tumor tissues were subjected to RNA sequencing; patients who were not previously treated; Meanwhile, patients meeting the exclusion criteria  were excluded. Then, the remaining patients in the TCGA-LUAD were randomly assigned to a training set and test set in a 1:1 ratio for subsequent analysis using the R package “caret”.The cancer genomic atlas (TCGA) program, hosted by the National Cancer Institute's (NCI), molecularly studied more than 20,000 primary cancers and corresponding normal samples across 33 cancer types and the genomic data of these 33 cancer types was uniformly reposited in the NCI's Genomic Data Commons (GDC), which facilitates precision medicine. The expression profile of TCGA-LUAD cohort was measured by using the Illumina HiSeq 2000 RNA Sequencing platform created by the University of North Carolina TCGA genome characterization center. Apart from that, the gene expression profile is generated using GDC mRNA quantification analysis pipeline and obtained from UCSC Xena (https://www.ncbi.nlm.nih.gov/geo/). GSE31210 was measured by Affymetrix Human Genome U133 Plus 2.0 Array including 226 LUAD samplesTo perform an independently external validation, we used GSE31210 as a validation dataset. The gene expression profile and clinical data were downloaded from the Gene Expression Omnibus (GEO) model, genes with Bonferroni corrected P <0.05 were obtained. Then, R package “caret” was implied to perform stratified random sampling based on survival status, which was randomly divided into training set and test set according the ratio of 1:1. The R package “glmnet” was used to perform a least absolute shrinkage and selection operator (LASSO) regression to penalized CPH model for minimizing the overfitting of the Cox regression on the training set. After that, the risk score of each patient was calculated utilizing the predict function based on this penalized CPH model in the training set, test set and validation set. Since time-dependent survival receiver operating characteristic (ROC) is an important method to evaluate the predictive ability of prognostic models, R packages “survivalROC” was utilized to perform time-dependent ROC for identifying optimal cutoff value corresponding to the highest true-positive rate and the lowest false-positive rate, which was then used to divide the LUAD patients into low-risk groups and high-risk groups. Subsequently, prognostic significance of the multigene combination was estimated by evaluating the differences of Kaplan-Meier survival curve analysis between the two groups in terms of overall survival (OS) and relapse-free survival (RFS). Furthermore, univariate and multivariable CPH models were utilized to identify independent prognostic factors associated with survival, and we considered risk score, age, gender, and pathologic stage as covariate. The above survival analysis was conducted using the R packages “survminer” and “survival”.After obtaining the above results, GSE31210 was used as an external validation dataset. Therefore, the risk score of each patient was calculated based on the regression coefficients of genes in the multigene combination, and the cut off value was also found as introduced above. According to the optimal cutoff value, the LUAD patients in the external validation set were separated into high-risk group and low-risk group. In addition, Kaplan-Meier survival curve analysis, univariate and multivariable CPH model were performed to validate the prognostic performance of discovery dataset. To further confirm the clinical relevance of the multigene combination, we compared the prognostication performance of the multigene combination with several well-established biomarkershttps://david.ncifcrf.gov/)In order to explore the potential molecular mechanisms of the prognosis-related genes affecting the survival of LUAD patients, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were conducted by using the DAVID online tool . Meanwhile, there were 226 patients in the validation dataset (GSE31210) , detailed characteristics of patients in the training set, test set, and GSE31210 were summarized in A total of 99 prognosis-related genes were identified in the TCGA-LUAD after Bonferroni correction. As a reP<0.001; figure The Kaplan-Meier curve of OS and RFS, and univariate CPH model of OS and RFS results suggested that patients in the 4-gene combination low-risk group was associated with better OS and RFS compared with those in the 4-gene combination high-risk group in the training set =11.962, 95% CI: 6.232-22.961, P<0.001; RFS, HR=9.281, 95% CI: 4.064-21.193, P<0.001; figure As shown in figure Given the fact that several well-established prognostic signatures or biomarkers have been introduced, we tried to compare the prognostic performance of these biomarkers with our 4-gene signature. Zhang et al. introduced a 3-gene signature based on the main members of kinesin family member genes , and they demonstrated that it can significantly stratify patients into low-risk group and high-risk groupIn order to have a rudimentary knowledge of the biological meaning of the prognosis-related genes, GO and KEGG enrichment analysis were conducted. As shown in Figure As shown in figure Given the low rate of 5-year survival as well as high rate of recurrence of LUAD patients, and also early diagnosis along with intervention can improve the clinical outcomes of LUAD patients, identification and evaluation of novel biomarkers for patients with LUAD is of great importance. In the present study, univariate CPH analysis was performed to analyze the relations between the expression of genes and the OS of patients with LUAD, and the results exhibited that 99 genes were associated with the OS of LUAD patients. LASSO (34) was introduced in order to improve the prediction accuracy and interpretability of regression models by forcing certain coefficients to be set to zero, and effectively to choose a simpler model that did not include those coefficients. Based on this, the above 99 genes were included into a LASSO penalized CPH model, and as a result 4 genes with none-zero coefficients in this model were obtained. Therefore, the risk score of each LUAD patients was calculated, and the 4-gene combination was built for prediction of overall survival and recurrence of patients with LUAD.The OS and RFS of LUAD patients in the 4-gene combination low-risk group significantly superior compared with those in the 4-gene combination high-risk group, and the 4-gene combination was shown to be an independently prognostic combination in LUAD. Actually, studies have reported that these four genes in the combination are associated with cancer progression or suppression. DKK1 was a member of the dickkopf family and members of this family were secreted proteins characterized by two cysteine-rich domains that mediate protein-protein interactionsMeanwhile, the GSE31210 dataset was used to validate the prognostication ability of the 4-gene combination. It has been proved that 4-gene combination can be used as an independent prognostic factor for LUAD patients in the validation cohort. Results of functional enrichment analysis of the prognosis-related genes suggested that the prognosis-related genes were mainly enriched in gene regulation, cell proliferation and signal transduction related GO terms and pathways, this was in accordance with the prognostic value of the 4-gene combination. In addition, we obtained good results by detecting the clinical potency of the 4 gene combination by nomogram and DCA. Collectively, we suggested that our 4-gene combination was a good supplement for the prognosis prediction of patients with LUAD.Although the four gene combinations showed excellent performance in the training set, test set and validation set, it had the following defects. First, this study was an integration and reanalysis of existing published LUAD gene expression studies. Although it showed good performance in prediction of the survival and recurrence of LUAD patients, it had not been verified by large scale prospective trials. Second, the associated mechanisms had not been validated in LUAD cells. Based on this, our follow-up researches will focus on verifying the conclusions of this study in terms of clinical application and molecular mechanisms.In conclusions, we introduced a 4-gene combination which could predict the survival of LUAD patients and might be an independent prognostic factor in LUAD.Supplementary figures and tables.Click here for additional data file.