Antiretroviral therapy (ART) transformed human immunodeficiency virus (HIV) infection into a chronic disease. Possible HIV-associated complications have emerged including cardiovascular diseases (CVD).This study aims to determine the heart rate variability (HRV) distribution and association between HRV and HIV treated with ART in a rural African population.This cross-sectional study included 325 participants of the Ndlovu Cohort Study, South Africa. HRV was measured using a standardized five-minute resting ECG and assessed by the standard deviation of normal RR intervals (SDNN), root of mean squares of successive RR differences (RMSSD), percentage of RR intervals greater than 50 milliseconds different from its predecessor (pNN50), total-, low- and high-frequency power. CVD risk factors were assessed using measurements  and questionnaires . We used a Wilcoxon rank test to assess differences in medians between HIV-infected and HIV-uninfected participants and multivariable linear regression to investigate associations between HRV and HIV treated with ART.Of the participants, 196 (61.4%) were HIV-infected treated with ART and 123 (38.6%) were HIV-uninfected. HIV-infected consumed less alcohol, 52% versus 35%, smoked less, were less physically active, more often attained lower education, 26% versus 14%, and had lower systolic blood pressure, 134 mmHg versus 140 mmHg, compared to HIV-uninfected. Medians of all HRV parameters were lower for HIV-infected participants. The model fully adjusted for CVD risk factors showed a significant inverse association between HIV treated with ART and log RMSSD (–0.16) and log pnn50 (–0.61). Although HIV-infected participants treated with ART presented with less CVD risk factors they had a lower HRV indicating an increased risk of CVD.– African HIV-infected participants on ART had less conventional CVD risk factors than HIV-uninfected.– However, HIV-infected participants had lower HRV than HIV-uninfected participants.– Lower HRV of the HIV-infected participants indicates that they are at a higher risk for CVD. In 2018, an estimated 62% of all people with human immunodeficiency virus (HIV) globally received antiretroviral treatment (ART) 4. Apart 4Although approximately 25.5 million HIV-infected individuals – nearly 70% of all people infected with HIV – live in sub-Saharan Africa (SSA), research on the association between HIV and CVD in this area is scarce. The differences in lifestyle, socio-economic factors and HIV subtype preclude generalization of data from Western countries to the SSA regions.One way of estimating CVD risk is by using surrogate markers . Heart r8910The aim of this study is twofold. First, we assessed differences between CVD risk factors of HIV-infected treated with ART compared to HIV-uninfected subjects. Second, we investigated the distribution of HRV and the difference between HRV of HIV-infected treated with ART compared to HIV-uninfected subjects while taking CVD risk factors into account.This cross-sectional study was embedded in the Ndlovu Cohort study (NCS) .The NCS is a prospective study in the Moutse area, Limpopo Province, South Africa and aims to provide a comprehensive understanding of the interaction between HIV and CVD in the black SSA population. From November 2014 until August 2017 this study recruited 1,040 HIV-uninfected and 887 HIV-infected participants through community campaigns, at local events and shopping centers as well as at the Ndlovu Medical Center (NMC) HIV clinic. The NMC was a large rural HIV treatment facility, contracted by the South African Department of Health, providing free-of-charge HIV treatment and follow-up to approximately 3,700 HIV-infected patients. Criteria for eligibility were age 18 years and older, being able to provide written informed consent and be committed to long-term follow-up. Routine physical examination was used to assess CVD risk factors. Full study procedures of the NCS have been described previously .All the participants of the NCS who came to the research site for a follow-up or baseline visit between August 2017 to December 2017 were approached for additional HRV assessment. Informed consent was obtained from each patient. We excluded HIV-infected not treated with ART, pregnant women and individuals unable to undergo the study procedures for any reason. The study conforms to the ethical guidelines of the 1975 Declaration of Helsinki as reflected by the ethics approval obtained from the Review Ethical Committee of the University of Pretoria (ref. number 227_2017).The NCS is well known in the community, regular community events are organized and a community liaison officer maintains the relationship with the community. However, patients and the public were not involved in the design, conduct and reporting of this research.HRV was measured in laying position with the upper body at a slight upward angle during five minutes using a 12-lead computer-based ECG Sampling box  and complementary software. All measurements were performed according to standardized procedures by two trained investigators who were unaware of the subjects’ HIV-status at the time the measurements were taken.Time and frequency domain parameters were measured. Time-domain parameters address the magnitude of variability and provide information about the vagal (parasympathetic) modulation of the heart, with higher variability generally reflecting greater parasympathetic modulation . Time-do14Frequency parameters use power spectral analysis of the beat-to-beat variations of the heart rate  . This me1614Information was collected on date of birth, sex, smoking status, alcohol use, chronic medication use and physical activity using standardized questionnaires, namely the WHO’s STEPS Instrument . PhysicaDue to technical errors during the HRV measurement 31 participants were excluded. The sample size was calculated a priori based on the difference between the mean SDNN of the HIV-infected treated with ART and uninfected. The difference was estimated to be 6, with a standard deviation of 18 . The minMissing data for medication use, BMI, systolic and diastolic BP were less than one percentage. A t-test and a Wilcoxon rank test were used to test for differences in continuous variables. Chi-square test was used to test for a difference in the categorical variables: smoking, alcohol use, income and educational level. The difference in the distributions of median HRV between HIV-infected treated with ART and HIV-uninfected participants was assessed using the Wilcoxon rank test.HRV parameters were log-transformed to reach a normal distribution. Linear regression analysis investigated the association of HIV and HRV parameters. In model 1 the association between HIV and HRV was investigated, while adjusting for age and sex. In model 2 the association was further adjusted for all CVD risk factors with a p-value < 0.2 in the univariable analysis. Model 3 was additionally adjusted for socio-economic variables. Data were analysed using R version 3.4.0.  and a twThe study population comprised 319 participants, of whom 196 (61.4%) were HIV-infected and all were treated with ART , we found a lower prevalence of conventional CVD risk factors in the HIV-infected population on ART compared to the HIV-uninfected population . These f244The increased risk of CVD as indicated by a lower HRV in the HIV-infected population on ART that we observed is in line with a large body of literature suggesting that HIV infection increases the risk of CVD 5. HRV haLimitations of this study are related to self-reported socio-demographic and lifestyle information which are potentially subject to social desirability and recall bias . FurtherMajor strengths of this study are the presence of an HIV-uninfected control group, allowing to gain insight into the role of HIV treated with ART on HRV and the taking into consideration of classic CVD risk for assessment of the effect of HIV treated with ART on CVD risk. As the study was undertaken in a general black rural sub-Saharan African population, the results may be generalizable to other rural SSA populations.To conclude, we observed a favourable CVD risk profile based on traditional CVD risk factors in the HIV-infected cohort population treated with ART. However, HIV treated with ART was negatively associated with HRV, denoting a decreased functioning of the parasympathetic and sympathetic nervous system and thus a higher risk of CVD. Our findings suggest that HIV-infection treated with ART is an independent risk factor for CVD. This underlines the importance of optimizing detection and treatment of manageable CVD risk factors to reduce CVD risk in people with HIV on ART.


Triangular growth patterns of pristine two-dimensional (2D) transition metal dichalcogenides (TMDs) are ubiquitous in experiments. Here, we use first-principles calculations to investigate the growth of triangular shaped oxide islands upon layer-by-layer controlled oxidation in monolayer and few-layer  Due to their reduced degrees of freedom, the quantum mechanical effects become significant, giving rise to fascinating electronic, mechanical, and optical properties otherwise absent in bulk materials4. However, the absence of a band gap in graphene presents a serious impediment in semiconductor electronics applications. This has tempted researchers to explore other low dimensional materials with varying functionalities10. Among them, 2D semiconducting TMDs, like 16. The high on-off ratio and intrinsic voltage gain of semiconducting 2D TMDs have enabled them to be used as atomically thin transistors21, photodetectors24 and light-emitting diodes27 with performance comparable to the well-known silicon devices.The successful synthesis of graphene28. Apart from the edges or defect sites, which are chemically active, pristine layered dichalcogenides are mostly passive due to the absence of any dangling bonds29. Despite the variety of properties, all monolayer pristine TMD systems with trigonal prismatic geometry are obtained as triangular nanoflakes on synthesis11. Experimental and theoretical studies on the growth mechanism of monolayer TMD nanoclusters suggest that the triangular geometry with all chalcogen atom edges are energetically most favorable33. Chalcogen terminated triangular nanodots of TMDs exhibit many interesting physical and chemical properties, like strong spin anisotropy near the Fermi energy with collective spin states at the edges that can be utilized in efficient spin-filtering devices34.2D TMDs can be prepared by various methods, like vapor-phase chemical reactions, wet-chemical synthesis and liquid exfoliation36 in monolayer and few-layer 37, ambient air38 and oxygen plasma doping, which is similar to conventional semiconductors39. The triangular island formation has also been reported in other studies40. Due to the temperature-dependent oxidation process, the triangular oxide patches increase in size, keeping their shape intact, until the full surface gets oxidized. The next layer of underlying pristine TMD starts getting oxidized only at elevated temperatures. This atomically thin TMD based oxide-semiconductor heterostructure created by layer-by-layer oxidation has interesting tunable electronic properties36. Moreover, charge transfer to the surface oxide layer makes them hole-doped35. Hence, these heterostructures can be used as field-effect transistors41 and photogating devices42.Our recent experimental and theoretical work36. We employ ab-initio techniques to capture the quantum mechanical effect in these reduced dimensions and systematically present our results in the following sections.Motivated by the enormous potential of these TMD based oxide heterostructures in electronic and optoelectronic device applications and their unique electronic properties, here we theoretically investigate these systems. We take a cue from the preferential self-formation of triangular nanoflakes of pristine TMDs and explore the underlying reason for similar triangular growth morphology of oxide islands on such pristine TMD systems. We have chosen our system to be 43. The calculations are performed at the level of the generalized gradient approximation (GGA) with the Perdew-Burke-Ernzerhof (PBE) exchange and correlation functional44. The electronic wave-functions are expanded using a plane-wave basis set with a cutoff energy of 520 eV. The 2D periodic tungsten selenide-oxide heterostructures are represented in a 47 to calculate the thermodynamic properties of the heterostructures within the framework of the quasi-harmonic Debye model  as implemented in the Vienna ab-initio simulations package (VASP)odel see .Figure 147. i-th species  and the vibrational contribution to the enthalpy and entropy (see 35. The molar Gibbs Free Energy at room temperature (298 K) and 0 GPa pressure, derived from the model (see Fig. However, we consider the Debye model in quasi-harmonic approximation as implemented in the Gibbs2 coderopy see . Moreovementclass2pt{minimHaving discussed the stability of the triangular oxide islands, we investigate the energetics of the Se substitution by O and the trend for the clusterization of the oxygen atoms into triangular patches at zero temperature. This is related to the short- and long-range ordering of the oxygen atoms within the two layers of chalcogen atoms. We consider a entclass1pt{minimaentclass1pt{minima35.Furthermore, to explain the preferential triangular self-formation of the oxide islands, we consider a entclass1pt{minima48. However, it has been observed that upon oxidation, this peak disappears35. In Fig. 49. Therefore, it is expected that these systems with triangular oxide islands will show optical absorption in the visible spectrum with possible light-harvesting applications.We further investigate the electronic properties of this in-plane heterostructures. It is well known that monolayer TMDs are direct band gap semiconductors, as shown in Fig. mentclass2pt{minimmentclass2pt{minim50 and can be extended to most 2D TMDs. Moreover, the TMD based oxide heterostructures can have potential use in various electronic and optoelectronic device applications.To summarize, we have investigated the reason behind the preferential triangular growth morphology of oxide islands on monolayer Supplementary Information


To perform an international comparison of the trajectory of laboratory values among hospitalized patients with COVID-19 who develop severe disease and identify optimal timing of laboratory value collection to predict severity across hospitals and regions.Retrospective cohort study.The Consortium for Clinical Characterization of COVID-19 by EHR (4CE), an international multi-site data-sharing collaborative of 342 hospitals in the US and in Europe.Patients hospitalized with COVID-19, admitted before or after PCR-confirmed result for SARS-CoV-2.Patients were categorized as “ever-severe” or “never-severe” using the validated 4CE severity criteria. Eighteen laboratory tests associated with poor COVID-19-related outcomes were evaluated for predictive accuracy by area under the curve (AUC), compared between the severity categories. Subgroup analysis was performed to validate a subset of laboratory values as predictive of severity against a published algorithm. A subset of laboratory values  was compared between North American and European sites for severity prediction.Of 36,447 patients with COVID-19, 19,953 (43.7%) were categorized as ever-severe. Most patients (78.7%) were 50 years of age or older and male (60.5%). Longitudinal trajectories of CRP, albumin, LDH, neutrophil count, D-dimer, and procalcitonin showed association with disease severity. Significant differences of laboratory values at admission were found between the two groups. With the exception of D-dimer, predictive discrimination of laboratory values did not improve after admission. Sub-group analysis using age, D-dimer, CRP, and lymphocyte count as predictive of severity at admission showed similar discrimination to a published algorithm . Both models deteriorated in predictive accuracy as the disease progressed. On average, no difference in severity prediction was found between North American and European sites.Laboratory test values at admission can be used to predict severity in patients with COVID-19. Prediction models show consistency across international sites highlighting the potential generalizability of these models. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of cases of coronavirus disease 2019 (COVID-19) in nearly every country. While most patients with COVID-19 have a mild form of viral pneumonia, an appreciable subgroup develops rapid onset of severe disease. Several large national studies have demonstrated that a variable and potentially significant proportion (ranging from 5–70%)  of hospiNumerous studies have reported models using clinical data, including laboratory values, to predict patients at high risk of severe disease.  However,We formed the 4CE Consortium  as an inWe included all patients hospitalized at participating 4CE sites with an admission date from 7 days before to 14 days after the date of their first reverse transcription polymerase chain reaction (PCR)-confirmed SARS-CoV-2 positive test result. The first admission date within this 21-day time window was considered the index admission date. Throughout this work, “days since admission” refers to this index date.Data were available from 36,447 patients from 342 hospitals (affiliated with 46 sites) across six countries: France, Germany, Italy, Singapore, Spain, and the United States. See eTABLE 2 for details about participating sites. Several sites collected data from multiple hospitals. In the United States, 170 medical centers of the US Department of Veterans Affairs were grouped into 18 regional divisions called Veterans Integrated Service Networks.Patients and the public were not involved in the design, conduct, or reporting, or dissemination plans of the research.We categorized the primary patient outcome as “ever-severe” or “never-severe” based on whether the patients, at any time during their hospitalization, progressed to severe disease—even if they later recovered from COVID-19. We defined “ever-severe” COVID-19 using the validated 4CE severity criteria based on the presence of at least one of the following codes in the EHR during the hospitalization: an order for any medication in two broad classes (intravenous anesthetics or cardiac inotropes), a collected partial pressure of arterial oxygen (PaO2) laboratory test (regardless of the result), an International Classification of Disease (ICD)-10 diagnosis code for acute respiratory distress syndrome or ventilator-associated pneumonia, or an ICD-10 procedure code for insertion of endotracheal tube or invasive mechanical ventilation . A more We chose this definition of severity because of the availability of standardized coded data describing medications, laboratory tests, diagnoses, and procedures. In contrast, other measures of disease severity, including requirement for mechanical ventilation or intensive care and death, are often unavailable in the EHR or are inconsistently recorded and are not easily ascertained. As an example, admission to traditional ICU spaces was not an effective measure of ICU admission when surge conditions required non-traditional placement.Following our prior approach , each coMost sites used the open-source i2b2 (Informatics for Integrating Biology and the Bedside) software platform to obtain the data. More than 200 organizations worldwide use i2b2 for purposes that include identifying participants for clinical trials, drug safety monitoring, and clinical and epidemiological research. Those 4CE sites with i2b2 used database scripts to directly query their i2b2 repository, calculate the counts and statistics, and export the data files. The 4CE sites without i2b2 used the Observational Medical Outcomes Partnership (OMOP) Common Data Model or their own clinical data warehouse solutions  and querying tools to create the required files.We focused on 18 laboratory tests associated with worse outcomes in patients with COVID-19 based on prior reports . We provAfter file upload, the online validation process checked the file and column names, column orders, data types, code values and ranges, and duplicated records. Then, we ran an R script for the following additional quality control checks: consistency of the total counts of ever-severe and never-severe cases across all datasets within each site, consistency between the 3-digit diagnosis codes and the ICD dictionary, and consistency of the range of laboratory data from each site with data observed from all sites. We contacted a site for site-specific quality control if the site laboratory values were consistently lower or higher than the other sites or otherwise implausible.We estimated the country-level daily incidence of new patients hospitalized with COVID-19 during the study period from January 23, 2020 to September 29, 2020. Specifically, for each country, we summed the daily incidence of new patients hospitalized with COVID-19 at each site within that country per 100,000 people of the country and multiplied this by an adjustment factor, defined as the ratio between the country’s overall inpatient discharge rate and the overall inpatient discharge rate of all 4CE sites in that country irrespective of COVID-19 status. We then reported the adjusted 7-day average incidence of new COVID-19 hospitalizations per 100,000 of the country population.We assessed the performance of laboratory values in predicting severity. We summarized the severity risk among different demographic subgroups by country based on the DerSimonian and Laird random effects meta-analysis of the site-specific risk estimates . For eacon average in the ever-severe group compared to the never-severe group.For each laboratory test, we assessed the ability of laboratory results measured at sequential days following the admission date to predict severity risk. We quantified the discriminatory capacity of each laboratory result by estimating the area under the receiver operating characteristic curve (AUC), assuming that the laboratory values within the ever-severe group or the never-severe group at each site followed either a normal distribution or a log-normal distribution. The AUC estimate quantified the probability that the laboratory result of a randomly selected patient in the ever-severe group was sufficiently different from that of a randomly selected patient in the never-severe group. For each laboratory value measured on a given day, we obtained AUC estimates within each site and combined them across sites using meta-analysis . In addition, we estimated site-level AUCs as the probability that the average laboratory value in an ever-severe group selected randomly from all sites is higher than the average laboratory value in a never-severe group selected randomly from all sites. Site-level AUC assessed the degree to which each laboratory value is different Recent literature suggested that combining multiple laboratory measurements may yield better severity predictions. We chose to validate a published composite severity risk score, calculated as a weighted average of several laboratory measurements, in comparison to our individual laboratory predictions. We chose  given thIn this study population of 36,447 patients, the incidence of hospitalization for COVID-19 largely tracked with population dynamics of COVID-19 cases  across dConsistent with prior studies 12], the, the12],We evaluated the predictive performance of individual and combined laboratory values available at admission and throughout hospitalization to predict our measure of severe disease. Specifically, we investigated the longitudinal trajectories, AUCs, and thresholds of eighteen laboratory values that were associated with severe disease in prior studies. Six of the labs were most robustly replicated in our analysis: C-reactive protein (CRP), albumin, lactate dehydrogenase (LDH), neutrophil count, D-dimer, and procalcitonin, as shown in When examining the distribution of between-site variation relative to average within-site variation stratified by country across all laboratory tests over 7-day windows, we found that the relative variation was <1, indicating that the site-level variations were much larger than the country-level variations (see eFIGURE 3). Using country-level data to evaluate prediction scores would incorrectly assume consistency of presentation of patients at each site within a country. As a result, we focused on site-level analysis of laboratory values thereafter.We pooled admission laboratory measures in ever-severe and never-severe patients across all sites (eTABLE 5). After log transformation, differences in admission laboratory values were significant for all laboratory tests . For mosGiven the potential value of laboratory values to better predict patients who transition to severe disease, we next examined the predictive performance of the laboratory values during the hospitalization  of six laboratory tests that distinguished ever-severe and never-severe patients over 14 days. Albumin and CRP were the best predictors of ever-severe disease. Compared to laboratory values on admission, prediction models based on CRP values over the 7 days after admission only marginally improved prediction. Maximum AUC for CRP and albumin was 0.66 and 0.68, respectively. Procalcitonin, neutrophil count, and LDH also had an AUC greater than 0.6. Thus, the utility of most laboratory tests in predicting severe disease from measurements subsequent to admission was minimal. One notable exception was D-dimer. Its performance in predicting severe disease improved from AUC=0.56 (95% CI of 0.50 – 0.63) at admission to AUC=0.68 (95% CI of 0.58 – 0.77) during the later stage of the hospitalization, suggesting that initial elevations of the disease may be less valuable for predicting ever-severe disease.Next, we performed a subgroup analysis to assess whether a combination of laboratory tests would improve prediction of severe disease over each individual laboratory test. Specifically, we chose to validate a published algorithm  that incGiven the unique multi-national nature of the 4CE consortium, we compared performance of the best performing laboratory tests  over time between continents, after grouping North American and European sites . OverallThis study builds upon the growing literature of COVID-19 severity prediction to report key findings pertaining to the optimal timing of inpatient laboratory results to predict a severe course of disease. We additionally used an international cohort to validate the generalizability of these models. First, we identified severe patients using a previously validated algorithm within the 4CE consortium. For patients hospitalized for COVID-19, we identified six laboratory tests with the highest predictive power to identify severe disease: CRP, LDH, procalcitonin, D-dimer, neutrophil count, and albumin. These laboratory tests are a subset of a list of tests previously associated with worse outcomes in patients with COVID-19. Second, The nature and construction of the 4CE consortium offers a number of key strengths and requires acknowledgement of important limitations. The consortium approach enabled the pooling of laboratory values across 342 hospitals with diverse healthcare practices. This showed that site-level (within-site and between-site) differences were greater than country-level differences. Interestingly, the severity predictive performance (AUC) of each laboratory study is remarkably consistent between North America and Europe. Despite the differences in the composition of ever-severe and never-severe patients across sites and countries, the directionality of laboratory values and the threshold for ever-severe disease shared many similarities. The design of the consortium and these analyses highlight that these findings are unlikely to be site-specific or the result of health care system dynamics; the predictive nature of identified lab tests is more likely to generalize. Additionally, given the diversity of sites, the findings are unlikely to be biased by a majority population demographic.The federated nature of analyses presented several additional limitations the consortium acknowledged and took measures to mitigate. First, EHR data have intrinsic noise, variable levels and causes of missing data, and policy effects on available documentation that will result in differences between sites. By leveraging a federated system of common EHR data elements and capturing site-level heterogeneity to identify patterns across hospitals and countries, the 4CE consortium is uniquely positioned to identify international differences in patient trajectories and hospital care that affect patient and population-level outcomes. To mitigate the intrinsic noisiness of EHR data, we performed extensive and iterative quality controls to address potential imprecision and incompleteness of datasets. Careful work with collaborators uncovered and addressed site-specific variations in data extraction and incomplete mapping of local EHR codes to desired data elements. Second, we used aggregate rather than patient-level data from each site for the current analysis in order to minimize privacy concerns and expedite the collaboration. Aggregation enabled rapid sharing of data across sites and countries. As such, we could not assess the prediction performance of a composite risk score at patient level but instead report the predictive accuracy at the site level. To address this concern, we used comprehensive statistical tools to perform meta-analyses across sites. Third, the severity algorithm can accurately identify patients hospitalized with COVID-19 who develop severe disease, but it cannot presently identify the clinical trajectory that leads up to such a transition. Given the limitations of the severity algorithm that we previously validated,  we couldWe plan future analyses of patient-level data at each site to fully assess the temporal trend of individual and composite laboratory tests throughout the disease course. We have established a platform of harmonized data that is enabling our consortium to study questions related to coagulopathy, acute renal failure, pediatric symptomology, neurological sequelae, and many other areas of interest of our members. As the pandemic evolves, we are also examining how the data collection assumptions made in the first wave are faring when presentations of those with chronic COVID-19 disease is now present within our health systems. Our future work related to severity prediction will optimize risk scores based on laboratory values and other clinical features to capture temporal changes in patient population and clinical care. Additionally, we are evaluating the case mix changes for hospitals over time that may influence identification and type of severe COVID-19 disease.We make several noteworthy observations. First, the key laboratory values emerging from our study represent the combination of acute inflammatory changes  and underlying physiology . Both baseline health state and acuity of physiologic response to severe viral infection predict the risk of severe COVID-19. Second, the relatively low AUCs are likely due to the large variation within each site for a given laboratory value. When used in combination, prediction performance was dramatically improved. Third, the performance of the combined algorithm was relatively stable--and did not improve--over the first days of hospitalization. Stability over time implies that laboratory values at admission can be used to differentiate those patients likely to develop severe disease almost as well as models from subsequent days of hospitalization. As such, the current study examines the timing of laboratory tests in distinguishing patients who develop severe disease from those who do not.Our systematic approach and extensive quality control allowed us to aggregate EHR data across sites and countries in a collaborative fashion at scale. The value of this work arises from leveraging these cross-country differences and similarities. While there may be dramatic differences in the outcomes of patients based on the complex interplay of comorbid conditions, natural history of the disease, and healthcare system dynamics, this fundamental similarity highlights a truism of disease: that there are clear and consistent patterns to the way humans react to disease. As we continue to build our collaborative and pursue future patient-level analyses, we will seek to uncover more subtle patterns and the role healthcare systems have in defining such perturbations.


The Coronavirus infectious disease 2019 (COVID-19) brings anesthesiologists and intensive care physicians to the mainstay of clinical workload and healthcare managements’ focus. There are approximately 900 anesthesiologists in Israel, working in non-private hospitals. This nationwide cross-sectional study evaluated the readiness and involvement of anesthesia departments in Israel in management of the COVID-19 pandemic. The impact on anesthesiologists’ health, workload, and clinical practices were also evaluated.An online questionnaire was distributed to all of anesthesia department chairs in Israel on April 14th. Each response was identifiable on the hospital level only. Informed consent was waived since no patient data were collected.Response rate was 100%. A decrease of at least 40% in operating-room activity was reported by two-thirds of the departments. Anesthesiologists are leading the treatment of COVID-19 patients in 19/28 (68%) Israeli hospitals. Israel Society of Anesthesiologists’ recommendations regarding intubation of COVID-19 patients were strictly followed . Anesthesiologists in most departments use standard personal protective equipment when caring for COVID-19 patients, including N95 masks, face shields, and water-proof gowns. Only one anesthesiologist across Israel was diagnosed with COVID-19 (unknown source of transmission). All department chairs reported emerging opportunities that advance the anesthesia profession: implementation of new technologies and improvement in caregivers’ clinical capabilities (68% each), purchase of new equipment (96%), and increase in research activity (36%).This nationwide cross-sectional study had a complete response rate and therefore well-represents the anesthesia practice in Israel. We found that Israeli anesthesia departments are generally highly involved in the health system efforts to cope with the COVID-19 pandemic. Anesthesia and airway management are performed in a remarkably comparable manner and with proper protection of caregivers. Ambulatory anesthesia activity has dramatically decreased, but many departments find opportunities for improvement even in these challenging times. The current coronavirus infectious disease 2019 (COVID-19) pandemic brings many challenges to the healthcare system. Since COVID-19 is primarily a respiratory disease, it often leads to respiratory failure, prolonged dependency on mechanical ventilation, and need for high intensity medical care [There are approximately 900 anesthesiologists in Israel working in non-private hospitals, caring for a national population of about 9 million people. Most Israeli anesthesiologists are registered in the Israeli Society of Anesthesiologists (ISA). Despite early assumptions according to which Israel will face thousands of COVID-19 mechanically ventilated patients in mid-April, the rapid transmission of the disease was contained, in part due to governmental orders of isolation, curfew, and social distancing . The peaThe present national cross-sectional study was thus set to evaluate various aspects of the COVID-19 pandemic in anesthesia departments, including anesthesiologists’ level of involvement in leadership and management, implementation of safety considerations designed to minimize COVID-19 infection and spread among anesthesia personnel, effects on anesthesiologists’ health and availability, as well as anesthesia departments’ activity. More so, the perspectives of departmental chairs on the opportunities arising from the COVID-19 pandemic were evaluated.N = 28), on April 14th 2020. The questionnaire was only identifiable on a departmental level. Reminders were set to be sent 3 days after the initial distribution to non-responders. The Tel-Aviv Medical Center institutional review board considered this survey of healthcare providers exempt from ethical approval, and consent was assumed by response to the survey. Since only organizational and institutional policy issues were addressed in this quality assurance project, with no identifiable or private health information, ethics committee approval and informed consent were waived.This nationwide cross-sectional study was conducted by an online questionnaire distributed to all anesthesia department chairs in Israel  and small  anesthesia departments. We used a convenience sample of all anesthesia departments in Israel. This manuscript adheres to the applicable STROBE guidelines for reporting of cross-sectional studies.The questionnaire was completed and submitted by all 28 anesthesia department representatives within 2 days, so no reminders were sent (response rate 100%). Average (standard deviation) completion time was 10 (7) minutes. One third  of anesthesia departments include the intensive care unit (ICU), and one half  are in large hospitals (> 500 beds).Leadership role and responsibilities: In two thirds of hospitals , anesthesiologists were leading COVID-19 patients’ treatment, either by themselves or in collaboration with intensive care and internal medicine physicians. There was no difference between hospitals in which the ICU is part of the anesthesia department  and those in which they are managed independently . Other responsibilities of anesthesia departments included managing COVID-19 patients’ airway , taking part in hospital crisis management and leadership (24/28), supervising the operating rooms (24/28), and clinical training and simulation to other disciplines in preparation to COVID-19 patients’ treatment (19/28).Anesthesia activity: As for elective surgical volume and anesthesia services, two thirds of departments reported a decrease of at least 40% in operating room activity , and 75% of departments reported cancellation of non-operating-room anesthesia cases.Safety considerations , usually with a separate access than the other operating rooms , and with a dedicated area for donning and doffing of PPE . Eleven hospitals noted this operating room operates under negative pressure.Airway management: When asked about specific components of airway management in COVID-19 patients, vast majority of departments reported that these intubations are performed by the most experienced provider , using rapid sequence induction , and after leaving only the minimal number of people necessary in the room . Video-laryngoscopes were the default device utilized according to 93% of respondents (26/28), and use of disposable airway equipment was reported by 75% of departments (21/28).Anesthesia personnel considerations: One quarter of departments reported that at least 10% of their manpower was absent due to home isolation orders for suspected contact with a COVID-19 positive person at some point during the current crisis . Nevertheless, only one anesthesiologist throughout the country was reportedly sick with COVID-19, while the source of infection remains unknown.Prospects arising from COVID-19 crisis  did not find any significant differences.This cross-sectional study collected data from all anesthesia departments in Israel, with a complete response rate. It was concluded within 2 days, and therefore well-represents the nationwide situation in the Israeli healthcare system in mid-April. Of note, hospital preparations for a large-scale pandemic aimed at coping with several thousands of mechanically ventilated COVID-19 patients were mostly completed at that point, while the actual number of ventilated patients across the country on April 16th was 140 .The dramatic decrease in surgical and procedural volume requiring anesthesia services reported in all hospitals around the globe was also evident in Israel as noted in the present study. Two key factors contributed to this in Israel: First, national regulations that went into effect in mid-March mandated active decrease of elective medical and surgical activity in public hospitals . SecondlWe found that anesthesia departments in Israel are highly engaged in COVID-19 crisis and in about two thirds of hospitals anesthesiologists led the way through the crisis. Anesthesiology chairs were the primary managers of different aspects of hospitals’ preparation processes, staff anesthesiologists trained other physicians in ventilation modes, conducted simulations, and many were shifted away from the operating room to treat patients in the ICUs.The nature of their job puts health workers overall, and anesthesiologists in particular, at increased risk of being infected with COVID-19. During the SARS outbreak In Toronto, Canada in 2003, one-third to one-half of all infections were in healthcare workers , 7. An eProtecting anesthesia teams has thus been the focus of hospital administrations across the country. One initiative was to train the staff in donning and doffing of PPE. A retrospective study evaluating risk factors for healthcare workers’ acquisition of the original SARS infection in 2003 found that workers who did not undergo proper infection-control training had higher risk of transmission as a result of caring for SARS-positive patients . SeveralAccess to protective equipment, during high risk procedures or while being exposed to suspected or infected COVID-19 patients, is another critical measure to avoid infection with COVID-19. The local, national, and international shortage of PPE has led the most influencing agencies as the World Health Organization and the United States Center for Disease Control and Prevention to publish guidelines on potential extended use and re-use of some disposable protective items , 16, 17.Several national anesthesia societies have published recommendations on the proper modifications to anesthesia induction and airway management , 12, 21.Finally, many departments were also able to find opportunities in the health crisis. Examples include innovative solutions to long-lasting gaps in information technologies, acquisition of long-needed medical equipment, and promotion of research projects.The main limitation of our study originates from its design – an survey offering anesthesia department chairs to participate and report the situation, as well as perceived achievements and challenges, of the departments they manage. Although anonymous in nature, we cannot verify the objective accuracy of participants’ answers, and some degree of reporting and recall biases cannot be ruled-out.This cross-sectional study provides a glimpse on anesthesia departments’ engagement in the COVID-19 crisis in Israel. It shows the inspiring role the anesthesia leadership took upon itself while keeping its members protected and safe, and despite the calamity and uncertainty found prospects for upgrading the profession. This encouraging message raises an opportunity to establish a more proper acknowledgement of the anesthesia profession and its importance, which used to suffer poor reputation and to lack public understanding of the various roles anesthesiologists are able to take in different setups .Additional file 1.


Concrete with crushed concrete aggregates (CCA) shows lesser compressive strength than reference concrete with natural aggregates. The goal of this study is to improve the strength of structural concrete with 53% and 100% CCA replacements without increasing the cement content. Thus, improvements in CCA quality are induced by combining mechanical and pre-soaking pre-processing techniques. Mechanical pre-processing by rotating drum is separately pursued on fine and coarse CCA for 10 and 15 min respectively. Results show, adhered mortar content and CCA water absorption reduces as pre-processing duration increases. Pre-processing influences CCA particle grading, flakiness index, shape index, void-content, unit-weight and density, jointly seen as packing density, which increases with pre-processing duration. Water amount to pre-soak CCA before concrete mixing is stable despite grading modifications, due to reduced water absorption resulting from mechanical pre-processing. Compressive strength and workability for pre-processed CCA50 and CCA100 concrete are comparable to reference concrete and show similar trends of improvement with packing density. Packing density markedly shows the quality improvements induced by pre-processing on CCA, maybe considered as one of the quality assessment indexes for CCA. Packing density should be investigated for other recipes to see the stability of the trend with workability and compressive strength. Crushed concrete aggregates (CCA) originating from structural concrete completes a closed-loop recycling when reused again in structural concrete. Using CCA originating from structural applications for low-utility applications, such as road backfilling, degrades the material value of CCA. By quality improvements, CCA is improved to suit high-utility applications like structural concrete, thus retaining material value. The efforts for the CCA quality improvements are necessary to channel larger amounts of CCA for structural concrete production, which as of 2018 is only 6% of the total 2.38 million tons of mineral waste from the construction sector in Sweden [Several studies show that by improving CCA quality the mechanical properties of the CCA concrete can match up to the properties of concrete with gravel or crushed rock—which is usually the parent concrete for the CCA. The quality improvements in coarse CCA fractions by mechanical pre-processing are shown to produce concrete with similar compressive strength as concrete containing aggregates of crushed stone or gravel .Quality of CCA is affected by the surface-adhered mortar giving CCA a higher porosity than natural gravel and crushed rock . A high The mechanical preprocessing techniques cause abrasion of CCA by milling either in a stationary drum containing a paddle on a rotating axis or in a rotating drum. Equipment such as eccentric rotor mill  has a roThe mechanical preprocessing of concrete rubble results in two major effects: firstly, abrasion of adhered mortar and secondly the comminution of low-density CCA or the abrasion of aggregate material from high density CCA. Screw abrading crusher and eccentric mill are seen to cause comminution of about 70% of the low-density CCA, reducing it to fine fractions . With auMechanical pre-processing in literature are either carried out on coarse ,10 or fiThe mechanical pre-processing of CCA is followed by washing on sieve to remove the abraded mortar particles to densify the CCA . Mechani3 [3, mechanical pre-processing after crushing results in an improved particle grading towards reference aggregate grading [Mechanical pre-processing by primary crushing causes the particle grading of fine CCA to be distant from natural aggregates ,17. Mech grading  as not j grading , the cloMechanical pre-processing additionally influences the CCA shape as seen in studies that use multiple crushing stages to pre-process the CCA to acquire a rounder shape similar to reference aggregates ,20. The Mechanical pre-processing influences properties—such as density, flakiness index, shape index, and particle grading—prominent in assessing aggregate quality for structural concrete according to standards SS-EN 12620 . These pImprovements in flakiness index and particle grading induced by crushing methods are shown to increase the concrete compressive strength and workability ,22, alsoBesides improving CCA density by mechanical pre-processing, there exist other pre-processing methods in literature that address the water absorption need of CCA, pre-processing by pre-soaking CCA with water ,30. A coThe novelty of this study is the mechanical pre-processing of both fine and coarse CCA to induce adhered mortar removal in comparison to previous literature where pre-processing is carried out in either coarse or fine fractions.A drum fitted with ribs with a rotating speed of 50 rpm is used to mechanically pre-process fine and coarse CCA separately in laboratory conditions. The mechanical pre-processing is evaluated for two durations of 10 and 15 min, considered optimum by literature for the CCA investigated in the respective studies ,11. MoreThe pre-processed aggregates are washed on sieves to remove the abraded adhered mortar or aggregate material. The pre-processing efficiency is determined firstly by the amount of adhered mortar loss along with the material damage occurring on CCA. This can be seen as a new contribution to literature, which solely addresses the adhered mortar loss in CCA by pre-processing. The improvements in CCA properties—such as density, water absorption, flakiness index, shape index, unit weight, void content, and packing density—are also investigated on pre-processed CCA.Concrete with mechanically pre-processed CCA is investigated for 100% (CCA100) and 53% (CCA50) replacements in the reference concrete recipe. The CCA replacement percentages aim to address practical issues such as the availability of waste and environmental issues such as exploitation of natural resources. CCA100 fits for a continuous supply of concrete waste, substitutes coarse and fine natural aggregates, thus preventing further waste. The replacement of fine aggregate fraction with CCA, as in CCA50, substitutes natural sand, which is critical for ecological preservation and a concern for Swedish concrete producers, who have already transitioned towards substituting coarse natural aggregates with crushed stone. From a logistics perspective, CCA50 alternative fits scarce concrete waste supply to make possible replacements on a continuous basis.The mechanical preprocessing of CCA is combined with pre-processing of CCA by presoaking based on the water absorption of the CCA. The mechanical pre-processing improves the density of the CCA by removal of adhered mortar resulting in a lower water absorption, which consequently reduces the amount of pre-soaking water. The CCA properties jointly influence the aggregate packing density, which in turn influences the compressive strength and workability of the concrete. Packing density concludes the collaborative effect of several aggregate properties.The experimental program, see All fine aggregates corresponding to 53% of total aggregate content (CCA50)100% of coarse and fine aggregates (CCA100)The CCA investigated in this study originates from the prefabricated rejects of an industrially active concrete recipe of grade C40/50, also the reference concrete recipe in this study. In the reference concrete recipe, the CCA replaces:The reference aggregates are crushed stone of size 8/11.2 mm and naturally graded aggregate 0/8 mm. The CCA fractions are 8/11.2, 0.5/4, and 0/4 mm; fine CCA fractions are differently sized from reference aggregates as after crushing the particle grading has been modified to fit reference concrete grading . The 8/1The mechanical pre-processing is based on autogenous cleaning method carried out in a metal drum rotating at 50 rpm, tilted horizontally at an angle of 18° and is lined with vertical ribs to facilitate material lift and cause abrasion by free fall. The coarse and fine aggregates are individually pre-processed and the aggregate quantity in a single batch corresponds to a third of the drum volume, the drum having a height of 30 cm and diameter 27 cm. The aggregate quantity is weighed before pre-processing to determine the loss by pre-processing.Two mechanical pre-processing alternatives with durations of 10 and 15 min denoted as MP10 and MP15 respectively are investigated. In addition, un-preprocessed aggregates, denoted by MP0, are also investigated. After pre-processing the aggregates are washed on sieves to remove the displaced material or adhered mortar. The sieve mesh size used for washing depends on aggregate fraction size, shown in initial) is soaked in water for a duration of 2 h and subsequently heated at a temperature of 500 °C for 2 h followed by immediate immersion in 20 °C water. The aggregates are finally oven-dried and their weight is measured as mfinal. The adhered mortar loss is calculated according to Equation (1).The loss of adhered mortar caused by mechanical pre-processing is assessed from the change in adhered mortar content before and after pre-processing. The adhered mortar content on an aggregate fraction is experimentally determined by a thermal shock resulting in the displacement of adhered mortar from the aggregate surface ,31. The The losses from the mechanical pre-processing alternatives MP10 and MP15 are analyzed for reference and CCA concrete aggregates. After mechanical pre-processing, the water absorption of the combined CCA fraction is tested by the modified pycnometer method  to deterThe CCA and reference aggregates are characterized by properties shown in The flakiness index of fine aggregates is investigated down to 1 mm by a Swedish method developed to characterize crushed rock aggregates .The packing density is derived for all concrete mixes—reference concrete, CCA50 and CCA100 in this study.The cement used in this study is CEM II/A-LL 42.5 R, and the superplasticizer is polycarboxylate-based with a dry content of 24 ± 1 weight %. The reference concrete has a water–cement ratio of 0.5 and is constant for CCA100 and CCA50 concrete mixes.Before mixing the CCA are pre-processed by momentarily pre-soaking with water based on the 15 min water absorption value of the combined CCA fraction determined by the modified pycnometer method . Since tFollowing the mixing process, the workability of the fresh concrete is determined by measuring the slump and flow diameter, once per batch, according to SS-EN 12350-5. Three cylinder specimens of size 100 mm × 200 mm are cast, demolded after 24 h and cured for 28 days submerged in a curing tank with water at 20 ± 2 °C according to SS-EN 12390-2. Compressive strength is tested according to SS EN 12390-3 at 28 days.Assessment of adhered mortar loss is a way to measure the effectiveness of the pre-processing alternatives of 10 and 15 min. Mechanical pre-processing is pursued separately for each CCA and reference aggregate fraction and is followed up by related operations washing and sieving. CCA may undergo both loss of material and adhered mortar, whereas reference aggregates undergo a loss of material. Therefore, the actual amount of adhered mortar removed from CCA by mechanical pre-processing is the material loss in reference aggregates deducted from the CCA loss as shown in Equation (2).Thermal shock before pre-processing on each fraction to assess the potential loss of material and adhered mortar.Losses by mechanical pre-processing to assess the actual material and/or adhered mortar lossThermal shock after pre-processing to determine the remaining material and adhered mortar left on the aggregate. The sum of the loss from mechanical pre-processing and thermal shock from stage 3 should only exceed by small margins the losses from thermal shock before pre-processing. The small margins validate mechanical pre-processing and related processes to give reliable results on the adhered mortar loss.Mass balance is made to control the losses occurring in the washing and sieving. Especially when both coarse and fines are mechanically pre-processed it is of importance to ascertain that adhered mortar loss is coming up just marginally from the processes of washing and sieving but more from actual mechanical pre-processing. Mass balance is made individually for each CCA and reference aggregate fraction in three stages:Mass balance for a coarse aggregate fraction 8/11.2 mm show that the potential adhered mortar loss given by thermal shock before pre-processing is 2.36%, In stage 2 mechanical pre-processing MP15, The effectiveness of alternative MP15 is assessed to at least 22% in all fractions by relating losses in mechanical pre-processing in stage 2 to losses in thermal shock at stage 1. The adhered mortar loss for 0/4 mm fraction is 22%, 0.5/4 mm is 26%, and 8/11.2 mm is 22% which makes MP15 the alternative with most uniform eroding effect for each fraction compared to MP10 where removed mortar amount shows higher variability.Grading curves are aggregate quality indicators, such that when CCA grading matches with reference concrete aggregates results in good concrete workability and compressive strength . The mecThe coarse CCA grading curve, To assess the closeness of grading curves across fine and coarse CCA fractions, combined grading curves are prepared for each CCA concrete as shown in The CCA grading curve investigated directly after crushing is improved by mechanical pre-processing to come closer to the reference concrete grading curve. However, there is still some gap between the grading curve directly after pre-processing (MP15 primary grading) and the reference concrete curve. Therefore, the grading curve is modified to get closer to the reference concrete grading by re-adjusting the share of CCA fractions in the concrete recipe, CCA proportions seen in The closeness of the modified CCA grading and reference aggregate grading is validated by the fineness modulus, seen in The packing density is derived from the weighed unit weight of the aggregate fractions in the concrete mix. The packing density is also influenced collectively by aggregate density, flakiness index, shape index, particle grading, unit weight, and void content. Therefore, the changes arising in these properties from mechanical pre-processing affects the packing density. The property majorly affecting packing density is the change in the unit weight and particle grading of mechanically pre-processed aggregates, seen in Improvements in packing density for CCA100 arises for all pre-processing alternatives and particle grading within  but for CCA50 arises only at MP15. Increased packing density for CCA50, with solely fines pre-processed, gives a particle grading closer to reference aggregates and leading to a better fit to reference concrete workability, In the case of reference aggregates, the packing density is seen to progressively reduce with pre-processing duration due to the material loss in the 0/8 mm fractions arising from the washing and sieving process following mechanical pre-processing.The CCA water absorption is expected to reduce with the removal of adhered mortar by mechanical pre-processing techniques, the water absorption results in this study are in agreement with this rule. The water absorption is seen to decrease after mechanical pre-processing for both CCA50 and CCA100 independent of pre-processing duration for primary graded CCA, see As the water absorption value remains unchanged for CCA100 at 5.7% with 10 min of pre-processing, the pre-soaking water amount is maintained constant in the MP0 and MP10 concrete mixes, see Similar to earlier findings, the flakiness index and shape index reduce with mechanical pre-processing. Flakiness index is tested on sample, shape index on individual particles and the correlation in between them being that aggregates having a high flakiness index also have a high shape index . This isThis study investigates unit weight and void content tests in an un-compacted state in order to address the influence of shape—flakiness, shape index on unit weight ,35. The With improved flakiness index of 8/11.2 CCA it is seen that unit weight increases gradually with each pre-processing duration. With increasing unit weight a decreasing void content is expected and this is seen for 8/11.2 CCA independent of pre-processing duration. Similarly, there is a visible reduction in the void content of fine CCA fraction 0.5/4 mm with MP10 and MP15. It is seen that this increase in unit weight for both coarse and fines is leading to an increase in the packing density and thus an improved compressive strength.Previous research indicates that the CCA density increases with the removal of adhered mortar by mechanical pre-processing, distinctly for lower density aggregates . For higThe influence of the packing density on the compressive strength of concrete is initiated by a comparison of packing density with the concrete density, measured at 28 days just before the compression strength is carried out, shown in The workability of the concrete produced with mechanically pre-processed CCA for 10 and 15 min durations are measured by the flow diameter, seen in Previous research relates the increase in concrete compressive strength for mechanically pre-processed CCA to the improvements in CCA density occurring with adhered mortar removal. In this study, the CCA density is not showing a uniform response across the mechanical pre-processing alternatives despite the adhered mortar loss. However, the concrete density is uniformly increasing with pre-processing duration for both CCA50 and CCA100, The packing density summarizes improvements in different aggregate properties arising from mechanical pre-processing and maybe seen as a property assessing CCA quality. Packing density is a good way to assemble the influences of different aggregate properties on the compressive strength and workability of the concrete. It may be interpreted as a bridging property between aggregate and concrete properties. This is ascertained for CCA50 and CCA100, which show the same tendencies for compressive strength and workability at different packing densities, see The stability of the relationship between packing density, workability, and compressive strength can be investigated for different concrete recipes. This relationship can be useful to pre-determine concrete properties arising from CCA of given quality shown by packing density.Reduces the most adhered mortar content in all CCA fractions and improves the grading of fine CCA by bringing it closer to the reference aggregate.Significant improvements in flakiness index and shape index of coarse CCA.The pre-soaking technique is compatible with mechanical pre-processing in optimizing pre-soaking water amount resulting from the reduction in adhered mortar content by abrasion.Both compressive strength and workability of CCA50 and CCA100 are reaching compressive strength of reference concrete.The aggregate properties collectively influence the packing density, which increases with increasing pre-processing duration for both CCA replacements.Packing density is the property concluding the collaborative effect of several properties such as density, particle grading, flakiness index, shape index, unit weight, and void content.The packing density has similar influences for compressive strength and workability for both CCA concrete, the packing density maybe used to indicate CCA quality along with water absorption and other properties confirmed by further investigations.For further research, the stability of the observed relationship between packing density, workability, and compressive strength may be investigated for different concrete recipes.Two mechanical pre-processing durations are investigated on concrete mixes with two aggregate replacement percentages. Between the two pre-processing durations, 15 min pre-processing is noticed to be optimum since:


Connectivity between brain regions has been redefined beyond a stationary state. Even when a person is in a resting state, brain connectivity dynamically shifts. However, shifted brain connectivity under externally evoked stimulus is still little understood. The current study, therefore, focuses on task-based dynamic functional-connectivity (FC) analysis of brain signals measured by functional near-infrared spectroscopy (fNIRS). We hypothesize that a stimulus may influence not only brain connectivity but also the occurrence probabilities of task-related and task-irrelevant connectivity states. fNIRS measurement  was conducted on 21 typically developing (TD) and 21 age-matched attention-deficit/hyperactivity disorder (ADHD) children performing an inhibitory control task, namely, the Go/No-Go (GNG) task. It has been reported that ADHD children lack inhibitory control; differences between TD and ADHD children in terms of task-based dynamic FC were also evaluated. Four connectivity states were found to occur during the temporal task course. Two dominant connectivity states (states 1 and 2) are characterized by strong connectivities within the frontoparietal network (occurrence probabilities of 40%–56% and 26%–29%), and presumptively interpreted as task-related states. A connectivity state (state 3) shows strong connectivities in the bilateral medial frontal-to-parietal cortices (occurrence probability of 7–15%). The strong connectivities were found at the overlapped regions related the default mode network (DMN). Another connectivity state (state 4) visualizes strong connectivities in all measured regions (occurrence probability of 10%–16%). A global effect coming from cerebral vascular may highly influence this connectivity state. During the GNG stimulus interval, the ADHD children tended to show decreased occurrence probability of the dominant connectivity state and increased occurrence probability of other connectivity states (states 3 and 4). Bringing a new perspective to explain neuropathophysiology, these findings suggest atypical dynamic network recruitment to accommodate task demands in ADHD children. Attention-deficit/hyperactivity disorder (ADHD) is one of the most prevalent neurodevelopmental disorders with continuous increases of prevalence rate  concept assumes static connectivity over temporal courses  and is a well-established analysis method  in particular data of typically developing children (TD) and children with ADHD during a task, such as an inhibition control task. The application of FC analysis using fNIRS to children also emphasizes the benefits of fNIRS measurement over less-practical fMRI measurement. By using task-based dynamic FC analysis, we addressed three questions: (1) Is shifting brain connectivity observed by fNIRS during the temporal task course? (2) How connectivity states within measured regions  shift (and how frequently) during the temporal task course? While previous studies focus on particular networks over temporal courses, the dynamic FC analysis takes into account all networks within measured regions for categorizing them in connectivity states. This analysis becomes more robust compared to the fluctuation of connectivity strength during the temporal course. (3) What are the differences between TD and ADHD children in dynamically shifted connectivity states? Compared to the static FC analysis, the dynamic FC analysis is capable to resolve the mechanism of shifting connectivity state in response to the task. Brain connectivity states expectedly change during the temporal task course, and the changes may phase-lock with stimulus information . We hypothesized that several connectivity states suggesting task-related and task-irrelevant networks may be alternated with different probabilities of occurrence. Brain-network impairment in ADHD subjects (as mentioned above) may also occur in atypical connectivity states and/or dynamic occurrence probabilities as implications of task demands. These results can provide ADHD neuropathophysiology from a noteworthy perspective and bring insights for clinical purposes.t-test). The TD group had higher  = 3.27) full-scale IQ scores than those of the ADHD group. All subjects provided oral consent, and written consent was obtained from all subject’s guardians according to the latest version of the Declaration of Helsinki. Previously related and current studies were approved by the Ethics Committees of Jichi Medical University Hospital, the International University of Health and Welfare, Chuo University, and Hitachi, Ltd. This study is collaboration research between Jichi Medical University Hospital, the International University of Health and Welfare, Chuo University, and Hitachi, Ltd. An ADHD-subject was excluded from further analysis because of an unexpected technical problem in data saving.Subject data described here originally came from two different previously reported datasets: (1) 21 medication-naïve ADHD-children data  was used to measure cerebral hemodynamic changes. Eight emitters and seven detectors were incorporated in a probe (in a 3 × 5 arrangement). The two probes were placed on the head of the subject according to the placement as described elsewhere  and converted into the product of hemoglobin-concentration change and optical-path length (ΔCHHb·L in mM·mm units) according to the modified Beer-Lambert law  method  with a window length of 12.0 s and window offset of one sampling point  are computed, the stronger connectivities between regions are interpreted. The total number of connectivity maps  for each subject and signal type is given by the total data points  minus the sliding-window points . To monitor the transition of dynamic connectivity from baseline to task and vice versa, fifty percent of the stimulus interval (GNG block) was selected as the sliding window. Using a longer sliding window than the stimulus interval will neglect subtle connectivity changes during transitions.In the first step, the channel-wise processed signals are correlated to each other  by using the ustering . Each clIn the fourth step, to evaluate the correctness of clustering, a parameter called “explained variance” is calculated. The explained variance (given as a percentage) indicates the ratio of between-cluster variances and total variances. As the cluster number increases, the between-cluster variance decreases, and the explained variance reaches approximately 100% . ClusterIn the fifth step, the elbow method was used to determine a threshold for cluster number, which, if surpassed, clustering is not effectively improved  in terms of occurrence probabilities of (O2Hb and HHb) connectivity states was statistically analyzed by using Wilcoxon rank-sum test.Subject-wise connectivity maps with labeled clusters were compartmentalized according to the block interval  of the baseline (10 s Go block and 3 s instruction), stimulus (GNG block), and post-stimulus (3 s instruction and 10 s Go block) intervals. The temporal information of the connectivity map was aligned to the onset of the connectivity window. The inter-stimulus interval was 30 s (including 24 s for the Go block and two 3-s instructions); thus, the connectivity maps in the post-stimulus and baseline intervals were unlikely to overlap. r = 0.40), whereas the centroid maps of clusters one and two are the most correlated (see r = 0.85).The relationship between cluster numbers and explained variance is shown in z transformed) for each state are shown in r = 0.87); however, the range of connectivity strength is stronger in the dynamic FC of state 2 (0.22–0.77 vs. −0.07–0.62). The significantly strong connectivities are found in the within-region of bilateral IFG – MFG and the between-region of left PrCG and left PoCG (r = 0.34). The low correlation between two connectivity states may suggest differences of connectivity pattern. For example, strong connectivities between bilateral MTG and intra-hemispheric IFG were observed in the connectivity state 2. On the contrary, the connectivity state 3 revealed stronger connectivities of intra-hemispheric ANG and SMG. Fifth, the dynamic FC of state 4  for the dynamic HHb FC  than those of states 3 and 4  for the dynamic O2Hb and HHb FCs.Second, there was no significant difference between the occurrence probability of states 3  and state 4 .Third, the occurrence probabilities of states 3 and 4 for the dynamic O2Hb FC .Fourth, the occurrence probability of state 1 for the dynamic HHb FC was significantly higher than that for the dynamic Op < 10−30) significantly affect occurrence probability. There was no evidence of the effect of signal type per se on occurrence probability . The statistical results are summarized in These four points suggest that the connectivity states  of states 3  and in the post-stimulus interval . The occurrence probabilities of state 2 for the dynamic O2Hb and HHb FCs differed in the case of both groups. Significantly increased occurrence probabilities of state 2 (dynamic O2Hb FC) were found at the baseline, transition of baseline-to-stimulus, and post-stimulus intervals for the TD group . On the other hand, occurrence probability of state 2 for the dynamic HHb FC in the case of the ADHD group , but it increased at the end of the stimulus near the post-stimulus interval .The effects of groups were found at different intervals for each connectivity state. For example, the ADHD group showed significant high occurrence probability . Occurrence probabilities of connectivity state dynamically fluctuated, but these fluctuations differed for the TD and ADHD groups. Furthermore, the chances of occurrence probability were seemingly stimulus-dependent. This result may explain atypical ADHD connectivity recruitment and be potentially useful as screening biomarkers.The current results of dynamic FC analysis show four alternating connectivity states during the execution of the GNG task. Even though connectivity states seemingly changed in random ways, strong connectivities within bilateral frontoparietal networks were apparently found in two dominant connectivity states . The frontoparietal network has been associated with attention control  networks may be associated with task demands . Thus, those two connectivity states are assumed to be task-irrelevant states. Strong connectivity affecting all regions  was detected in connectivity state 4. A global effect is propagated from cerebral vessels to the local regulation of neurovascular coupling  in task switching has been demonstrated  were significantly higher in the case of the ADHD children than those in the TD children during sparse temporal task course. It was reported that the relationship between DMN connectivity and ADHD severity is positively correlated . Even though the clustering analysis is reasonably robust, we have yet to confirm whether the selected window length was appropriate enough for the current task paradigm. The effect of stimulus lengths on window lengths needs to be addressed. Besides the SWC analysis, hidden Markov model has been proposed to reveal the probabilistic model of connectivity state , have been reported (Shakil et al., To the best of our knowledge, the current study is the first to use fNIRS signals for investigating task-based dynamic FCs. Connectivity states shifted in alternate ways during the temporal task course. Four connectivity states, which likely represent two dominant task-related states and two task-irrelevant states, were found. Furthermore, the characteristics of TD and ADHD children could be distinguished by the occurrence probability of connectivity states. In the case of ADHD children, the occurrence probability of the dominant connectivity state decreased, and that of the assumed task-irrelevant states within the stimulus interval increased. These results provide a new perspective in explaining ADHD neuropathophysiology related to atypical dynamic state recruitment and promote clinical benefits.All datasets generated for this study are included in the article.The studies involving human participants were reviewed and approved by Ethics committees of Jichi Medical University, the International University of Health and Welfare, Chuo University, and Hitachi, Ltd. Written informed consent to participate in this study was provided by the participants’ legal guardian/next of kin.YM, MN, TI, and TT designed and performed the experiments. SS conceived the presented idea and performed the computation analysis. MK, HA, TT, and ID verified the analysis. YM, AM, TF, TY, and ID supervised the finding of this work. SS wrote the manuscript and ID elaborated it. All authors discussed the results and contributed to the final manuscript.SS, TF, HA, MK, and AM are employed by the Hitachi. Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Faces and voices are very important sources of threat in social anxiety disorder (SAD), a common psychiatric disorder where core elements are fears of social exclusion and negative evaluation. Previous research in social anxiety evidenced increased cerebral responses to negative facial or vocal expressions and also generally increased hemodynamic responses to voices and faces. But it is unclear if also the cerebral process of face-voice-integration is altered in SAD. Applying functional magnetic resonance imaging, we investigated the correlates of the audiovisual integration of dynamic faces and voices in SAD as compared to healthy individuals. In the bilateral midsections of the superior temporal sulcus (STS) increased integration effects in SAD were observed driven by greater activation increases during audiovisual stimulation as compared to auditory stimulation. This effect was accompanied by increased functional connectivity with the visual association cortex and a more anterior position of the individual integration maxima along the STS in SAD. These findings demonstrate that the audiovisual integration of facial and vocal cues in SAD is not only systematically altered with regard to intensity and connectivity but also the individual location of the integration areas within the STS. These combined findings offer a novel perspective on the neuronal representation of social signal processing in individuals suffering from SAD. Consistently, one of the key features in SAD are cognitive biases towards socially threatening signals in faces and voices  can be conceptualized as maladaptive evolutionary mechanism which developed parallel to a social hierarchy which was no longer based on physical dominance but rather social skills relying on nonverbal and later verbal communication signals , 2. The d voices . Correspd voices –9], braid voices , 7, 10],d voices , 7. Mored voices . Taken tIn the present study, we aimed to bridge the astonishing gap between the scientific need for data on the audiovisual processing and integration of nonverbal cues from face and voice in SAD  and the In 18 individuals with SAD and 18 low SA healthy controls, we investigated how SAD affects the magnitude and topography of cerebral face-voice-integration. The latter was determined using a functional magnetic resonance imaging (fMRI) experiment comparing the responses to dynamic bimodal face-voice combinations displaying various expressions with the monomodal presentations of the stimuli . Based on the assumption that voices and faces would be more salient to individuals with SAD than to low socially anxious individuals we hypothesized that in SAD stronger hemodynamic responses to face-voice-combinations would be found in the multisensory integration area of the posterior STS and the amygdala. Second, we expected the increase in hemodynamic activation to occur for face-voice-combinations in comparison to both, faces and voices alone due to the expected increase in stimulus salience compared with the unimodal stimuli.The standard voxel-by-voxel analysis was complemented with the spatial analysis of individual integration maxima and functional connectivity (FC) analyses to further characterize the hemodynamic correlates of face-voice-integration. Additional fMRI experiments were performed to determine the cerebral voice- and face-sensitivity measured as increased hemodynamic responses to voices or faces, respectively, in comparison to other types of stimuli as additional source of information on the functional characteristics of areas with SAD-related alterations in face-voice-integration.Eighteen individuals with SAD  and 18 low socially anxious healthy control individuals  years were included in the study. They were recruited at the Universities of Tübingen (n = 23) and Greifswald (n = 13) through notices in public venues and email circulars at the Universities of Tübingen and Greifswald. All participants underwent the Structured Clinical Interview for DSM-IV . In theThe protocol of human investigation was approved by the local ethics committees where the study was performed , and the study was performed according to the Code of Ethics of the World Medical Association  and its later amendments. All participants gave written informed consent before their inclusion into the study.The stimulus material consisted of videos (1.6 s) of faces speaking 60 words with neutral or emotional  prosody and congruent facial expression. The stimuli were recorded from six professional actors, allocated to 12 blocks with five stimuli each, and were all presented auditorily (A), visually (V), and audiovisually (AV) totaling in 180 stimuli per participant. Across blocks, the stimuli were randomized on condition that the blocks were balanced for the depicted emotion and the gender of the speaker. Within the blocks, stimulus presentation was randomized. Likewise, within each modality the block sequence was randomized while the modalities of the stimulus blocks were randomized on condition that the block sequence did not contain more than two adjacent blocks from one modality. Auditory stimulation was carried out with MR compatible headphones . Visual stimuli were back-projected onto a screen placed in the magnet bore behind the participant's head and viewed by the participant through a mirror system mounted onto the head coil. The participants were asked to indicate the second “male” stimulus within each block by pressing a button on a fiber optic system  with their right index finger to ensure constant attention to the stimuli. The experimental design was validated previously and further details on stimulus material and experimental design can be found elsewhere .The voice-sensitivity experiment was designed in form of a block design experiment with 24 stimulations blocks and 12 silent periods (each 8 s) with a passive-listening task and stimulus material based on the study by Belin et al. . The stiIn the face-sensitivity experiment, pictures from four different categories  were shown within a block design. The stimulus material and design has been adapted from previous face processing studies , 25. EacBoth experimental designs have been used previously , 26, 27 3, field of view 192x192 mm2, 64x64 matrix, flip angle 90°) and structural T1-weighted images  were acquired. The time series comprised 204(/239) images for the face-voice-integration experiment, 302(/368) images for the face experiment and 195(/232) images for the voice experiment. A field map  was recorded.MRI data were recorded with a VERIO 3T  and a PRISMA (Tübingen) scanner . Functional images (34(/30)  axial slices captured in sequential descending order, 3 mm thickness + 1 mm gap, TR = 2.0(/1.7) s, TE = 30 ms, voxel size: 3x3x4 mmIBM SPSS Statistics Version 25  was used for the analyses. Differences between SAD and HC with regard to gender, study site (chi square tests), age, SA severity (LSAS), general state and trait anxiety , and verbal intelligence (MWT-B) (t tests) were systematically investigated.http://www.fil.ion.ucl.ac.uk/spm) was employed for imaging data analysis. To exclude measurements preceding T1 equilibrium, the first five EPI images from each fMRI experiment were removed. The preprocessing included realignment, unwarping employing a static field map, coregistration of anatomical and functional images, segmentation of the anatomical images, normalization into MNI  space with a resampled voxel size of 3 × 3 × 3 mm³, temporal smoothing with a high-pass filter (cutoff frequency of 1/128 Hz), and spatial smoothing using a Gaussian kernel . The error term was modeled as an autoregressive process  , visual (V), and audiovisual stimuli (AV) in the face-voice-integration experiment, voices (V), animal sounds (A), and environmental sounds (E) in the voice-sensitivity experiment, and faces (F), houses (H), objects (O), and scenes (S) in the face-sensitivity experiment] were separately modeled using a box-car function representing the block duration (8 s in the voice-face-integration experiment and the voice-sensitivity experiment and 16 s in the face-sensitivity experiment) convolved with the HRF. Results from the individual first-level general linear models were used to produce contrast images  for each participant which were then included in second-level random-effect analyses. These minimum difference contrasts were computed for each participant as the minimum of the contrast images AV – A and AV – V for face-voice-integration, V – A and V – E for voice-sensitivity and F – H, F – O and F – S for face-sensitivity. Age, gender and study site were included as covariates in all second level analyses.The analytical strategy comprised two arms:1.) Voxel-wise analysis of the audiovisual integration effect  in the whole study sample, in SAD, and in HC as well as of between group differences regarding the audiovisual integration effect . Statistical significance was assessed at p < 0.001 at voxel level and cluster-level FWE correction (p < 0.05) for multiple comparisons across the whole brain.2.) Spatial distribution analysis of the individual audiovisual integration maxima  within the audiovisual integration areas Bonferroni-correcting the results for multiple comparisons across the three spatial axes and two hemispheres .Results section.Significant effects were post-hoc characterized and validated. To this aim, mean contrast estimates for all three experiments  were extracted from significant clusters. These analyses included the associations of integration effects with parametric measures of social and general anxiety, and individual movement patterns in the scanner ] differ between SAD and HC. The BOLD signal time-course of the seed regions, extracted from a sphere (radius: 2 mm) around the individual peak-activation voxel within the seed region adjusted for effects of interest was used as physiological variable. Each condition  was then defined as a separate psychological input variable and contrasted . The PPI was estimated as the product of the vector of the psychological variables and the deconvolved activation time course . The phyThe psychometric and demographic characteristics of the participant groups (SAD/HC) are given in Audiovisual face-voice-integration correlates were observed bilaterally in the temporal cortex adjoining the middle and posterior parts of the STS in the whole sample  was determined by the smaller difference between AV and A stimulation than between AV and V in almost all participants . Additionally, the increased face-voice-integration effect in SAD was statistically driven by stronger increases for AV compared to A in SAD as compared to HC  while the activation increase under bimodal stimulation as compared to unimodal visual stimulation was decreased in SAD   = 1.0, p > 0.05; y: t(34) = 5.3, p < 0.001; z: t(34) = 3.3, p = 0.011] and more anterior in the left STS   ≥ 2.1, both p ≤ 0.046]. The FC increase during face-voice-integration {i.e., AV-max was significant in SAD  but not in HC }. The latter lack of a face-voice-integration effect in HC was mainly based on a non-signicant increase in FC during audiovisual than during visual stimulation  whereas the FC increase for audiovisual compared to auditory stimulation was significant   were included as covariates with the only exception of the relationship between group and the position of the individual integration maximum on the z-axis in the right STS when correcting for general trait anxiety. Moreover, when the positions of the face-voice-integration maxima were included as covariates, the hemodynamic face-voice-integration effect remained significantly associated with the diagnosis of SAD in the bilateral STS clusters . Moreover, the SAD-related increases in face-voice-integration effects in the bilateral temporal voice areas were found to be statistically stronger than in the amygdalae and the face-sensitive cortex areas ] ng [e.g. ]. Furtheng [e.g. .Moreover, as the site of increased face-voice-integration correlates corresponds well with the posterior maximum of the TVA slightly medial of area TE3 in the temporal cortex , increasAlso, SAD-related increased hemodynamic activation during audiovisual integration the voice-sensitive auditory association cortex was statistically stronger than within the corresponding face-sensitive cortices of the pSTS  and the Interestingly, this putative mechanism might also explain that SAD-related activation increases during face-voice-integration in SAD in the amygdalae were statistically weaker than in the voice-sensitive midsection of the STS and did not reach any level of significance. The amygdala has been discussed to be central in the integration of stimulus salience across different nonverbal communication channels . It coulThe significant linear associations between the hemodynamic and functional connectivity correlates of face-voice-integration in the STS and SA severity suggest that they reflect spectral cerebral features of SA in the population and are not necessarily bound to the clinical significance of SA with a diagnosis of SAD.The topographical analysis of the individual integration maxima, unexpectedly, revealed an anteriorization of the maximal integration effects along the STS irrespective of individual movement patterns in the scanner as a second component of the cerebral representation of face-voice-integration in SAD. Validation analyses confirmed the complimentary nature of the effects observed in the two analyses focused on the magnitude and the location of face-voice-integration effects. In other words, irrespective of the location of the individual face-voice-integration maximum, SAD is associated with increased hemodynamic face-voice-integration correlates. Thus, the inclusion of this non-standard type of data analysis in future studies may afford an additional informative perspective on the cerebral representation of SAD but also other psychiatric disorders and, keeping in mind the spectral nature of the effect, potentially also individual psychometric characteristics.And also from the point of view of sensory integration research, these results might be relevant. It appears that the identical mathematical measure of integration could reflect different underlying neuronal processes: the integration of vocal and facial expressions into a unified percept in the multisensory neurons of the pSTS , 42 in hFrom the clinical perspective, our results suggest that SAD-related cerebral alterations in social cognition exceed the domains of unimodal social cue processing as previously demonstrated for faces , 34 and The present design established a clear link between SAD and the increased hemodynamic integration correlates of vocal and facial information. However, the functional relevance of the observed activation patterns remains unclear. Therefore, further studies including measures of SAD-related behaviors  are needed to elucidate if the observed effects potentially reflect a consequence of dysfunctional perceptive learning, either as correlates underpinning pathological processes in convergence with current models of SA , 45, or Including dynamic displays and several different types of nonverbal expressions, the stimulus material was composed to encompass a broad range of naturally occurring nonverbal social communication. However, the study design does not allow the differentiation between neutral and emotionally negatively or positively valenced expressions all of which are subject to negative cognitive biases , 48–52 bFinally, two further points should be noted: First, the sample size in our study was relatively small. Second, correction for multiple comparisons based on cluster size in combination with standard voxel-wise statistical thresholds in the SPM software has been criticized as potentially too lenient with an increased risk of false positives, especially in studies with weakly significant results , 54. TheIn summary, our study connected two important areas of neuroscience: the research on threat-related signal processing in SAD and the research on the sensory and perceptual integration of signals from face and voice. We demonstrated increased hemodynamic face-voice-integration correlates in SAD anterior to the multisensory cortex of the pSTS within the TVA and a concomitant increase in FC with the striate and peristriate visual cortex. It appears plausible that these effects reflect increased extraction of emotional information from voices supported by an enhanced contribution of visual cue characteristics to voice processing potentially also mirroring the neural processes underlying increased salience of bimodal face-voice-combinations as compared to voices alone in SAD. Further, our results show not only an increase in the hemodynamic correlates of face-voice-integration but also SAD-related crossmodal interactions in voice-sensitive areas  during the perception of naturalistic dynamic face-voice-combinations. These are potentially indicative of a shift of the intermodal balance between voice and face processing during the perception of audiovisual nonverbal signals. Validation in future studies provided, it is quite conceivable to investigate the clinical and therapeutic relevance of this intermodal imbalance for example in form of a perceptual training study aiming to rebalance the processing of faces and voices. Moreover, the topographic analysis highlighted the anteriorization of the individual integration maxima as an additional component of the cerebral representation of SAD and advocates this analysis type also for studies in other psychiatric disorders and individual psychometric characteristics. Still, there remains the evident need for further research to fully unravel the neural bases of the multimodal integration of social threat and that of social threat carrier signals like faces and voices in SA.The datasets generated for this study are available on request to the corresponding author.The studies involving human participants were reviewed and approved by Ethik-Kommission an der Medizinischen Fakultät der Eberhard-Karls-Universität und am Universitätsklinikum Tübingen. The patients/participants provided their written informed consent to participate in this study.BK, DW, ME, and CB conceived and designed the study. SW, ML, TE, ME, CB, and BK acquired the data, and BK, DW, CB, TE, SW, and AW analyzed and interpreted the data. BK drafted the manuscript and all authors critically revised the manuscript.This work was supported by grants of the Fortüne-Program of the University of Tübingen  and the German Research Foundation Open Access Publication Fund.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.