Both metal and semiconductor nanoparticles enable inhibition of radiative decay rate by one order of the magnitude as compared to that in vacuum, whereas a metal nanosphere cannot perform the overall decay inhibition since slowing down of radiative decay occurs only along with the similar growth of its nonradiative counterpart whereas a semiconductor nanoantenna is lossless. Additionally, at normal orientation of the emitter dipole moment to a nanoparticle surface, a silicon nanoparticle promotes enhancement of radiative decay by one order of the magnitude within the whole visible range. Our results can be used for other photochemical or photovoltaic processes, and strong radiative decay enhancement found for dielectric nanoantennas paves the way to radiative decays and light emitters engineering without non-radiative losses.In the context of using portions of a photosynthetic apparatus of green plants and photosynthesizing bacteria in bioinspired photovoltaic systems, we consider possible control of the chlorophyll excited state decay rate using nanoantennas in the form of a single metal and semiconductor nanoparticle. Since chlorophyll luminescence competes with electron delivery for chemical reactions chain and also to an external circuit, we examine possible  The overall scenario from a photon absorption by a light harvesting complex to an electron release by a reaction center for further chemical processing takes less than 100 ps and has a quantum yield close to 1 3. Photophysical aspects of photosynthesis basically end at the stage of an electron release by a reaction center for further involvement in chemical processes. A chlorophyll molecule in the reaction center can be excited either directly by absorbing red or blue light itself or by energy transfer from other chlorophyll molecules and/or from carotenoids absorbing the green light. One more function of carotenoids is modulation (control) of the reaction center efficacy by means of the so-called non-photochemical quenching of chlorophyll photoluminescence 5. This non-photochemical quenching enables not only plant survival under conditions of ultrastrong illumination but also helps to modulate photosynthesis rate under condition of other threats, e. g., water shortage. At the same time low but non-zero green light absorption by chlorophyll molecules is supposed to enable chlorophyll in deep leaf tissues to be used for light harvesting under condition of low illumination levels6. The above interplay of photostimulated processes in chlorophyll and carotenoids represent an example of the multivariant interactions in green leaves in the course of photosynthesis7.Photosynthesis is the major process on the Earth producing organic matter from inorganic precursors promoted by light absorption and involving multiple stages like energy transfer, electron transfer, relaxation processes, the three paths in the photosynthesis scenario. The first, and the principal one, is the release of the high-energy electron to the chemical processing chain. The second is the radiative decay with intrinsic lifetime of a few nanoseconds. The third one is the nonradiative, probably both intrinsic and extrinsic decays influenced by the ambient medium polarity, temperature and tentatively, by the carotenoids-generated impact, to adjust the electron release rate in accordance with volatile illumination level and other external conditions. In a solution, molecular chlorophyll features the quantum yield up to 35% in polar solvents like water, alcohols, amines9 and much lower values in nonpolar solvents whereas in green leaves it varies from 5% to 1% with temperature rise from 77 K to 275 K10.Excited electron states of a chlorophyll molecule have actually the vice versa. This important correlation discovered in 198911 is widely applied for in vivo photosynthesis studies in plants14.Chlorophyll photoluminescence does not bear significance as a stage or a process directly participating in or contributing to photosynthesis. Instead, it can be purposefully used only as a signature to monitor the rate of photosynthesis. High photoluminescence was found to typically correlate with lower photosynthesis yield and enhanced light—matter interaction resulting from high local concentration of electromagnetic radiation in the sub-wavelength vicinity of metal nanobodies, their junctions or assemblies, the so-called “hot spots” develop nearby and therein. There are actually 3 processes modified by the proximity of a metal nanobody to a quantum system under consideration . These are (i) enhanced excitation rate resulting from the incident light local concentration; (ii) modified (enhanced or inhibited) radiative decay rate, often referred to as the photon local density of states (LDOS) effect; (iii) modified non-radiative decay rate owing to energy transfer to a metal nanobody resulting in heating. Additionally, under condition of strong light—matter coupling, excitonic plasmon-polaritons can be generated 16 enabling light energy transfer through a metal-dielectric system mediated by electronic excitation in the matter nearby. Since strong light—matter coupling needs special and rather tough conditions, in what follows it will be left beyond consideration.Plasmonics is known to deal with metal enhanced fluorescence (MEF)18 which implies an arrangement enabling domination of metal enhanced incident light intensity over the loss in quantum yield Q resulting from non-radiative decay enhancement. For a perfect emitter with Q = 1, a non-radiative decay channel promoted by a metal proximity will always result in lower Q. The situation resembles to large extent the effect of an antenna in radiophysics thus proving the emerging conception of nanoantennas in nano-optics19. However, similar to radiophysical antennas, proximity of a metal body offers an option to substantially increase the intrinsic efficiency of an emitter with considerable internal losses, i. e., in the optical language, with Q ≪ 1. This may result in the overall photoluminescence intensity enhancement over several orders of the magnitude for poor emitters20 and, what is extremely essential in optoelectronics, even in enhancement of the efficiency of electrically pumped light-emitting devices, semiconductor LEDs or organic ones, OLEDs, where making use of the incident intensity enhancement is not the case at all22.In a typical plasmonic experiment with fluorescing species, experimenters tend to make use of the positive balance of the above 3 processes. The most typical plasmonics application to photoluminescence is referred to as 23 and fluorescence29 in the context of bioinspired photovoltaics30, i. e., to use delivery of an electron from a chlorophyll reaction center to the outer electric circuit. However, in the context of the above discussion, enhancement of chlorophyll photoluminescence cannot directly assist in higher photocurrent generation. Moreover, metal-enhanced fluorescence typically occurs along with enhancement of excited state decay rate thus bypassing electron transfer into an external circuit. It seems also that many experiments on plasmonic improvement of photovoltaic devices were not successful because of the enhanced recombination rate preventing efficient charge separation in a device. Accordingly, the early consideration of plasmonic effects in photochemistry suggested photostability improvement owing to a fast bypass created for an excited state by a metal proximity31. Nowadays, e. g., semiconductor quantum dots and proteins have been found to feature higher photostability in presence of metal nanobodies33.For molecular species involved in photosynthesis, plasmonic effects have been experimentally shown to increase light absorptionlong-lived excited states are favorable since long lasting electron excited states raise up a probability for an excited electron to be involved in the other processes rather than to return radiatively or non-radiatively to the ground state. Is there a break for optical nanoantennas to bioinspired photovoltaic components which rely on implementation of photosynthetic fragments? The above discussion shows that it is inhibition of excited state decay which could improve performance of bioinspired photosynthetic photovoltaic cells. The intrinsic non-radiative decay process can hardly be altered by nanophotonic approaches whereas the radiative decay does depend upon the properties of the local environment not only in the context of a solution polarity but also being fundamentally dependent on the photon local density of states (LDOS) which is defined by a nanoantenna. According to the Barnett—Loudon sum rule34, for a given point in space, enhancement (inhibition) of the radiative decay rate of a quantum emitter as compared to that in vacuum will necessary be compensated by the opposite changes otherwise so that the overall modification of radiative lifetimes over the wide frequency spectrum will always tend to zero. This fundamental property has been qualitatively confirmed both theoretically and experimentally for microcavities and photonic crystals (see Chapter 14 in35 and refs therein for detail). The similar phenomenon of coexisting radiative rate enhancement and inhibition should occur in metal and dielectric nanoantennas but it seems that inhibition of radiative decay with nanoantennas remained beyond systematical analysis except for the early work36 where preliminary analysis was made within an electrostatic approximation for which application to bigger nanobodies is questionable. In the experiments, inhibition of radiative decay was not purposefully pursued for typical light emitters39.For the both photochemical reactions and photovoltaic devices the 40 throughout enabling reliable predictions for wide range of nanoparticle sizes as well as accounting for possible manifestation of magnetic properties in non-magnetic dielectric spheres.In this work, we consider a number of simple cases which are feasible with metal and semiconductor nanoparticles and show that semiconductor antennas rather than metal ones promise noticeable inhibition of the excited state decay for an emitter in the wide spectral range embracing the chlorophyll luminescence spectrum of approximately 600–800 nm, and at the same time feature noticeable enhancement depending on emitter dipole moment orientation. We use the Mie theoryγrad modification with respect to the vacuum rate γ0 for a representative emission wavelength 700 nm. Normal orientation gives radiative decay enhancement whereas tangential orientation gives inhibition. A pronounced inhibition maximum about 103 times occurs for tiny particles (30 nm or less) at very short distances about 1 nm. In what follows we consider the two representative cases of 2a = 20 nm and 2a = 50 nm . Gold nanoparticles were found to be less efficient. The nanoantenna effect dramatically depends on an emitter dipole orientation. Figure γrad/γ0 becomes just slightly less than 1.Figure n was found to have no essential effect on the radiative decay properties. Figure n = 1.5. One can see, the main difference from the case n = 1 is a long-wave shift of the enhancement factor spectra which is generally very important for metal-enhanced luminescence experiments. However radiative decay inhibition remains to occur approximately in the same spectral ranges as for n = 1, though being less pronounced than in Fig. Ambient medium refractive index 41. The more dramatic restriction is that a metal nanoantenna inevitably brings non-radiative losses. Therefore, even if the conditions for inhibited radiative decay are met, enhanced non-radiative decay rate γnonrad can result in the overall total decay rate  promoted by metal nanobodies may deteriorate the overall performance of a photosensitive device even in case when plasmonic effects will enhance light energy absorption and photoelectron emission.Thus one can see that metal nanoparticles can promote enhanced decay rate more readily than inhibiton of decay. Inhibited decay is noticeable at fixed dipole orientation only. We consider this results can be useful in the context of plasmonic effects applied to photodetectors and also to photovoltaiс structures46. Nowadays, Krasnok and co-workers ingeniously suggested that entirely dielectric antennas including simple solid spheres can have the similar effect on light emission as the metal ones but without non-desirable non-radiative losses47. A single silicon nanosphere has been suggested as a starting design for the visible based on Si high refractive index n > 3 whereas absorptive losses are low owing to indirect interband transitions up to photon energies in the violet range (about 400 nm). The conception of a dielectric nanoantenna has gained the close consideration last years51. For the infrared spectral range from 1 to 2 µm, radiative decay rate has been calculated showing both enhanced and inhibited decay under certain conditons53. First experimental evidence of enhanced luminescence using entirely dielectric antennas has been reported54. An emitter decay rate when being placed inside a solid dielectric sphere  was also found to be essentially modified55.The early hint to remarkable property of spontaneous decay modification by a dielectric nanobody can be found in the paper by Chew in 1987We found that Si nanospheres with diameter 100 nm or less do promise more than one order of the magnitude slowing down in the decay rate Fig. . Bigger At normal orientation of an emitter dipole moment with respect to a sphere surface, Si spheres were found to enhance radiative (i.e. full) decay by one order of the magnitude in the wide spectral range and for the wide range of emitter—spacer distances. Sample results for this case are given in Figs 56. Therefore dipole orientation of a chlorophyll molecule can be monitored by surface enhanced Raman scattering (SERS) using Raman signatures of certain bonds. Namely, the bonds oriented parallel to the dipole moment of the target electronic transition will experience minimal SERS factors in the same experimental configuration.Dipole orientation can be independently monitored by Raman signal enhancement studies. Photon LDOS equally affect spontaneous emission and scattering of light57P0 being the radiation power in vacuum, and Prad being the power emitted by a dipole when located at the point of interest. The radiation power can be found by integration of the normal component of Poynting vector over the surface embracing the emitting system. The ratio in Eq.(D(Ω) in its turn59 can be calculated as described in Methods.To gain more insight in the origin of the inhibited spontaneous decay, we examine the angular diagrams of emitted power and trace changes in the diagram pattern as well as in radiation power for a dipole emitter near a spherical dielectric antenna. It is known that the rate of spontaneous transitions can be calculated asThe results are presented in Fig. 2) but refractive index of oxides are low as compared to silicon. At first glance, spherical silicon nanoantenna looks like a useful computational model rather than a really feasible nanoobject. However there are certain approaches that can fabricate nearly spherical silicon nanoparticles by laser printing60 and colloidal61 techniques. Yet another reasonable geometry of a silicon nanoantenna is a nanodisk on a dielectric substrate which can be nowadays readily fabricated by means of electron beam lithography and etching. When compared to nanospheres, nanodisks represent a body with radial symmetry but with sharp rectangular edges. For high dielectric permittivity of a nanoantenna material analytical methods appears to be inefficient and the problem can be analysed only by numerical techniques.There are commercially available oxide spherical beads  nanoantennas. For the simplest and experimentally affordable case of colloidal spherical nanoparticles we found that silver nanoparticles promise approximately 2-fold decay slowing down as compared to that in vacuum by means of simultaneous 100-fold inhibition of radiative decay and similar enhancement of non-radiative one. This 2-fold inhibition needs a dipole alignment parallel to a sphere surface, and can be only slightly improved towards 2.5 times inhibition by using a thin dielectric shell over a metal particle surface. Contrary to a metal nanoantenna, the dielectric one based on silicon promises more than one order of the magnitude inhibition of the decay but without bringing non-radiative losses promoting an additional decay path. However, inhibition occurs only for a dipole moment parallel to the sphere surface, as was in the case with metal antennas. Thus adsorption specificity, surface functionalization and/or chemical linking should be applied for the desirable dipole orientation. Additionally, we found that silicon nanoantennas offer more than one order of the magnitude enhancement of radiative decay within the visible for the dipole orientation normal to the sphere surface, and approximately 2-fold enhancement under condition of randomly oriented dipoles. Thus dielectric (semiconductor) nanoantennas pave a way to low-lossy control of excited states including both enhancement and inhibition of decay, the latter being of importance in bioinspired photovoltaics.63. The radiative γrad and the total γtot decay rates for an emitter can be calculated asγ0 is decay rate in a free space without a nanobody, ‘Re’ means the real part of the expression, jn(x) and 64, k0 is wave number in vacuum, r0 = a + Δr is the distance from a nanoparticle center to an emitter, a is the radius of a spherical nanoparticle, n is the refractive index of ambient medium, and65, primes denote derivatives, and ε is the nanoparticle complex dielectric permittivity.We consider the simplest case of a single solid spherical nanobody as a nanoantenna to control the excited state decay rate. The calculation scheme has been described elsewhereγnonrad, resulting from Joule losses in a metal body, i. e. γtot = γrad + γnonrad. For a dielectric nanobody the imaginary part of dielectric permittivity ε can be neglected in many practical cases, then total and radiative rates coincide, i. e. γrad = γtot = γ holds.The total decay rate near a metal body typically higher than the radiative one because of the contribution from the non-radiative counterpart In the case of averaging over dipole moment orientations, the decay rates (labeled with an ‘A’ subscript) read,h thickness of material with refractive index ns, the Mie coefficients Am,Bm should be replaced66,b = a + h is the external nanosphere radius, and other notations readFinally, in the case of a spherical nanoparticle with a dielectric shell with 67. We use perfect match layer boundary conditions68. In all calculations, the data on metal and semiconductor dielectric functions were taken from70.The numerical simulations for nanodisks were performed with a help of a commercial software from Lumerical, based on the Finite-difference time-domain methodr → ∞, in this case equations can be reduced to the more simple for m. In spherical coordinates one has,Etot = Erefl + E0 and Htot = Hrefl + H0 are the full electric and magnetic fields, respectively, Erefl and Hrefl are reflected fields, E0, H0 are source fields. Here с is speed of light in vacuum, and n is the unit vector normal to the sphere surface. Square brackets [×] denote vector product and the ordinary brackets (·) denote scalar product. The D(Ω) function is then calculated asThe radiation power for an emitter can be found by integration of the normal component of Poynting vector over closed surface for


Asthma attacks are common and have significant physical, psychological, and financial consequences. Improving the assessment of a child's risk of subsequent asthma attacks could support front‐line clinicians’ decisions on augmenting chronic treatment or specialist referral. We aimed to identify predictors for emergency department (ED) or hospital readmission for asthma from the published literature.We searched MEDLINE, EMBASE, AMED, PsycINFO, and CINAHL with no language, location, or time restrictions. We retrieved observational studies and randomized controlled trials (RCT) assessing factors  associated with the risk of ED re‐attendance or hospital readmission for acute childhood asthma.Three RCTs and 33 observational studies were included, 31 from Anglophone countries and none from Asia or Africa. There was an unclear or high risk of bias in 14 of the studies, including 2 of the RCTs. Previous history of emergency or hospital admissions for asthma, younger age, African‐American ethnicity, and low socioeconomic status increased risk of subsequent ED and hospital readmissions for acute asthma. Female sex and concomitant allergic diseases also predicted hospital readmission.Despite the global importance of this issue, there are relatively few high quality studies or studies from outside North America. Factors other than symptoms are associated with the risk of emergency re‐attendance for acute asthma among children. Further research is required to better quantify the risk of future attacks and to assess the role of commonly used biomarkers. Physicians treating asthmatic patients are identifying rather poorly who is at risk of asthma attacks.Several factors have been associated with a higher risk of attack among asthmatic children,22.1We conducted systematic searches of bibliographic databases as described in the Supporting Information (E‐Table S1). All databases were searched from their inception to the present with no language of publication restriction. Searches were carried out by a Cochrane Information Specialist up to 9th January 2017. Duplicate references were removed using reference management software (EndNote X7). The reference list of each selected publication was hand‐searched for relevant studies.2.2Studies with the following criteria were included: (1) cohort and case‐cohort observational design analyzing factors related to asthma clinical history, previous treatment, lung function, biomarkers, or readily measured environmental exposures; or controlled trials that involve a lifestyle or social  interventions; (2) asthmatic children aged between 5 and 15 years old (among the age range of the study) recruited from the ED or ward, treated for an acute asthma exacerbation, included as participants; (3) emergency re‐attendance or hospital readmission due to an asthma attack listed as outcomes.The list of abstract and titles was reviewed to exclude publications that were clearly not contributory on this basis and duplicate titles. Full text articles of selected papers were obtained via University library and inter‐library loan and reviewed for eligibility, excluding those not fulfilling inclusion criteria.2.3Data were extracted by three independent authors using a standard data extraction form. Possible disagreements were resolved by discussion. RevMan 5 and Endnote X7 software were used to assist in the collection and management of data from abstracts and papers.2.4Studies’ accuracy and risk of bias was assessed using the criteria of the Cochrane Handbook for Systematic Reviews of Interventions by three independent authors. Observational studies’ quality was also assessed using the Newcastle‐Ottawa Quality Assessment Scale,2.5Data from comparable studies were combined in quantitative analyses. We pooled data using a random effect model in RevMan5, creating pooled estimates of effects for Hazard and Odds Ratios separately. Reports that presented the results using mean values, with no other data, were not included in the meta‐analyses. We used the generic inverse variance as the analysis method for some of the pooled estimate of effects, as some studies only reported Odds or Hazard Ratios.I2 statistic.I2 was high, if either there were few studies (a situation where I2 can be imprecise or biased), or if the studies found a consistent direction of effect which would imply that factor was worth consideration in future prospective studies.We represented an estimate of the degree of variation between study outcomes using the 3A total of 3259 records were identified and screened for eligibility with one additional paper obtained through reference list screening Figure . Forty‐t3.13.1.1Twenty‐three studies were retrospective analyses of health‐care databases. There were six prospective cohorts, three randomized‐controlled trials (RCT), and four with other prospective designs. Most studies were carried out in North America (21 in USA and 3 in Canada). Participants were recruited among inpatients admitted for acute asthma in most of the studies (27) ; and asthma characteristics .3.2The number of reports with low, unclear, or high risk of bias was 22, 7, and 7, respectively. Those with an unclear risk of bias lacked information on relevant aspects of the methods, mainly sample selection, or did not state clearly the number or factors studied in order to assess reporting bias. The details of the risk of bias assessments are shown in E‐Table S2.3.33.3.1The effect of age on the future risk of ED or hospital readmission was examined in 16 studies (E‐Table S3). There was a marked variation in the age group classification and statistical methods used for the comparisons, precluding a meta‐analysis of this factor. Studies were consistent in reporting that younger children had a higher risk of ED or hospital readmission.N = 67706; I2 = 52%) in the pooled analysis of data from 17 studies  in the pooled analysis of three studies reporting Hazard Ratios . Four other studies reporting Hazard Ratios for hospital readmission showed no association between black ethnicity and hospital readmission rate . One paper studying hospital readmission was excluded from the meta‐analysis as results were stratified by age and sex.The effect of ethnicity on ED or hospital readmission was included in 18 reports, using different classifications. The most frequent was the comparison between black or African‐American and white or other origins, and the risk of readmission for asthma. There was an increased rate of ED re‐attendance among African‐American compared to white children   , consistent with the variation in study design and predictor used.Twenty‐one reports examined SES as a predictor for ED or hospital readmission for asthma. The specific predictor used differed, with public insurance (vs private or other) or low household income being the most frequent markers adopted for low SES. A meta‐analysis of data from four studies showed increased odds of ED re‐attendance for acute asthma in children of low SES  )  .Seven reports analyzed the risk of hospital readmission among children with other concomitant allergic diseases, including allergic conjunctivitis, allergic rhinitis, or eczema. The pooled OR of six of these studies showed an increased risk of hospital readmission for asthma for children with concomitant allergic diseases . The results from one of the studies (Taylor 1999) was not included in the meta‐analysis and forest plot as it pooled together all children who had not had an asthma attack in the baseline year (whether they had asthma or not).Eight reports included data on the risk of ED or hospital readmission according to a history of previous hospital or ED admissions, either in the previous 12‐24 months (the most common) or ever in life. The three reports studying ED re‐attendance odds ratios are shown in Figure N = 40367; I2: 78%), showed an increased rate among children with a history of previous ED or hospital admissions for acute asthma  and the three studies reporting hazard ratios for hospital readmission  . The type of predictor and definition of severity varied greatly between studies, precluding a meta‐analysis. The findings related to severity as defined by treatment were inconsistent.3.3.3Ten papers examined aspects of follow‐up after the index ED or hospital admission (E‐Table S5). Three studies explored the effect of the Children's Asthma Care (CAC) measures set implementation, which comprises providing reliever medication and systemic corticosteroids for children admitted to hospital for asthma, and discharging them with a home management plan. They showed no effect on ED re‐attendance after the initial admission for asthma and two of them demonstrated a reduced risk of hospital re‐admission after the implementation of the CAC measures. One further study showed a decreased risk of both hospital readmission and ED re‐utilization for acute asthma after Home Management Plan Care implementation (part of CAC).Five studies analyzed the effect of different follow‐up visit characteristics and ED or hospital readmission for asthma with disparate outcomes. Three reports studied the effect of receiving an asthma action plan at discharge on the risk of ED or hospital readmission. Two of them were combined  showing no association.3.3.4N = 1041; I2: 49%) for hospital readmission for acute asthma for those exposed to tobacco smoke . One other paperP‐value: not significant).Five studies included data on ETS, producing a pooled odds ratio of 1.60 , caregiver's situation , asthma triggers, exposure to allergens or pollution and home characteristics, adherence to asthma treatment, characteristics of index asthma admission, and home remediation interventions of water infiltration. The outcome definitions and specific exposures studied were highly heterogeneous between studies meaning no robust consensus conclusions could be drawn.44.1Asthma is a very common reason for emergency attendance. Clinicians are therefore often faced with decisions on whether to increase treatment and who to refer for a specialist opinion. This systematic review and meta‐analysis has identified a history of previous ED or hospital admissions as the major risk factor for emergency care and hospital readmissions for acute asthma in children. Further, our results indicate that children of African‐American ethnicity (compared to white or other ethnicity), low socioeconomic status (as measured by having public insurance or low family income), with concomitant allergic diseases  and being younger than 5 years of age, appear at a greater risk of subsequent emergency care visits or hospital readmissions for acute asthma.4.2This systematic review answers a relevant question with public health implications for future asthma management. It has been developed in accordance with best practice and using an extensive search with no time or language publication restrictions to ensure the inclusion of potentially suitable studies. Risk of bias was assessed and presented for each included study separately. We were also able to undertake a quantitative analysis of the most relevant predictors, increasing the relevance of our findings.4.3The data collected had a moderate to low strength of evidence, due to the quality of the included studies and the inconsistent findings in some of the factors reported.I2). In most of these cases we present pooled effect size to give an indication of the scale and direction of effect. However, it is not currently possible to derive precise estimates of effect size based on the available literature, and well‐designed prospective studies are required.Variation in study design and outcomes precluded meta‐analysis for some factors. In other instances, meta‐analyses demonstrated significant variation between studies when compared to error within studies  were also associated with a greater risk of hospital readmission for asthma. Previous work has shown that treatment for allergic rhinitis  is associated with lower rates of unscheduled care use.Asthmatic children with a history of a previous ED or hospital admission for acute asthma had 2‐5.8 times more risk of ED re‐attendance and 2.5‐3 times more risk of a hospital readmission. This was therefore the clearest factor related to asthma that was associated with future risk. Similarly, other studies have identified several variables related to previous healthcare utilization for acute asthma that are associated with future risk of severe asthma attacks.5In conclusion, we have identified individual‐level and factors related to asthma severity that are associated with a greater risk of future asthma attacks requiring emergency care or hospital readmission. This description of the current evidence base and its limitations could help inform future prospective studies that robustly assess the magnitude and interaction of such risk factors. In future, being able to identify children at risk of future asthma attacks requiring emergency care will guide specific interventions such as educational sessions, management of comorbidities, and personalized treatment adjustments. This approach has the potential to reduce the chance of long‐term complications such as loss of lung function, psychological morbidity, and death.Additional supporting information may be found online in the Supporting Information section at the end of the article.Figure S1. Forest plot for the associations of concomitant allergic diseases  with hospital readmission for acute asthma in children using a random effects model (odds ratios).Figure S2. Forest plots for the associations of being offered an asthma action plan at discharge with emergency department re‐attendance or hospital readmission for acute asthma in children using a random effects model (odds ratios).Figure S3. Forest plots for the associations of second‐hand tobacco smoke exposure (ETS) with hospital readmission for acute asthma in children using a random effects model (odds ratios).Click here for additional data file.Table S1. Search report Asthma exacerbation risk factors in children searches. October 2013 model (odds ratios).Table S2. Statistical Methods and Risk of BiasTable S3. Association between age and risk of ED or hospital readmissionsTable S4. Association between asthma severity, control and baseline treatment and risk of ED or hospital readmissionsTable S5. Association between asthma follow‐up and management after index admission or ED visit for asthma and risk of ED or hospital readmissionsClick here for additional data file.


Any physical activity in the elderly is better than none at all for reducing cardiovascular risk, according to an 18–year study in more than 24 000 adults published recently in the European Journal of Preventive Cardiology. ‘We know that regular physical activity has major health benefits,’ said first author Dr Sangeeta Lachman, a cardiologist at the Academic Medical Centre, Amsterdam, the Netherlands.‘Healthy adults are advised to do at least 150 minutes a week of moderate–intensity or 75 minutes a week of vigorousintensity aerobic exercise to reduce their risk of cardiovascular disease,’ she continued. ‘These recommendations are based primarily on research in middle–aged adults and we wanted to know whether regular physical activity yields comparable cardiovascular health benefits in elderly people.’This study compared the association between different levels of physical activity and the risk of cardiovascular disease in middle–aged to elderly individuals. The hypothesis was that exercise would be equally beneficial in reducing cardiovascular risk in middle–aged and elderly individuals.The study included 24 502 adults aged 39 to 79 years who participated in the European Prospective Investigation into Cancer (EPIC) Norfolk cohort, a prospective population study that is part of the 10–country collaboration EPIC study. The cohort was primarily designed to assess dietary and other determinants of cancer, but data were also collected on determinants of cardiovascular disease.Participants were recruited between 1993 and 1997 from registries of general practices in the county of Norfolk, UK. On enrolment into the study, participants completed a health and lifestyle questionnaire, underwent a standardised physical examination and gave blood samples. Physical activity during work and leisure time was assessed with a questionnaire and participants were categorised as active, moderately active, moderately inactive and inactive.Patients were followed up until 31 March 2015 for hospitalisation or death from cardiovascular events (coronary heart disease or stroke), which were identified by linking the participant’s unique National Health Service number with the East Norfolk Health Authority (ENCORE) database. Physical activity levels and time to cardiovascular events were investigated in three age categories: less than 55, 55–65 (middle–aged), and over 65 years of age (elderly).During a median follow up of 18 years, there were 5 240 cardiovascular disease events. In elderly participants, hazard ratios for cardiovascular events were 0.86, 0.87 and 0.88 in moderately inactive, moderately active and active people, respectively, compared to inactive people. In those aged 55–65 and less than 55 years, the associations were directionally similar, but not statistically significant.Dr Lachman said: ‘We observed an inverse association between physical activity and the risk of cardiovascular disease in both elderly and middle–aged people. As expected, there were more cardiovascular events in elderly participants, which could explain why the association only reached significance in this age category.’‘Elderly people who were moderately inactive had a 14% reduced risk of cardiovascular events compared to those who were completely inactive,’ continued Dr Lachman. ‘This suggests that even modest levels of physical activity are beneficial to heart health. Elderly people should be encouraged to at least do low–intensity physical activities such as walking, gardening and housework.’She concluded: ‘Given our aging population and the impact of cardiovascular disease on society, a broader array of public health programmes are needed to help elderly people engage in any physical activity of any level and avoid being completely sedentary.’


To investigate the indications, surgical strategy and techniques, safety, and efficacy of robot‐assisted minimally‐invasive internal fixation of pelvic ring injuries.The clinical data of 86 patients with anterior and posterior pelvic ring injuries who underwent robot‐assisted minimally‐invasive internal fixation were retrospectively analyzed. The patients included 57 men and 29 women aged between 22 and 75 years, with an average age of (40.2 ± 13.6) years. According to the Tile classification, there were 5 (5.8%) type A2, 48 (55.8%) type B, and 33 (38.4%) type C fractures. The surgical plans were formulated based on the injury type of the pelvic ring, the effectiveness of the reduction, and the integrity of the osseous channel. Posterior pelvic ring injuries were treated with robot‐assisted percutaneous cannulated screw fixation of the sacroiliac joint. Anterior pelvic ring injuries were treated with robot‐assisted percutaneous cannulated screw fixation of the pubic ramus, INFIX fixation, or a “hybrid” fixation. The surgical complications and the efficacy of the surgical treatments were analyzed.A total of 274 screws were inserted with robotic assistance, of which 262 screws were successfully inserted to a satisfactory position on the first attempt. The number of screws placed per person was 3.2 on average, and the average operation time was 175 min (35–280 min). Fluoroscopies were performed an average of 29.1 times , and it took 6.1 s to place each screw. There were 13 unsatisfactory guiding needle placements during the surgeries, among 7 of which cutting or penetration of the cortex was re‐planned until satisfactory insertions; 1 penetrated the pubic cortex, causing hemorrhage of the “crown of death,” and was changed to “hybrid surgery”. The robot‐assisted surgical wounds all healed by primary intention with satisfactory position and precision of screw insertions. All patients were followed up for 3–6 months, with an average of 4.2 months. There were two postoperative fixation failures, in which both patients had separated symphysis pubes after hybrid surgery. The average Majeed score at the last follow‐up was 92.4 points.Robot‐assisted surgery is accurate and minimally invasive, with a high success rate for one‐time screw placement and satisfactory clinical results. The indications and surgical strategy should be rigorously selected, the level of surgical techniques mastered, and the operating procedures standardized, all of which may help to prevent surgical complications. Robot‐assisted surgery provides a novel modality for the minimally‐invasive treatment of pelvic ring injuries. Pelvic fractures are often caused by high‐energy trauma resulting in injuries of both anterior and posterior pelvic rings. Simultaneous anterior and posterior pelvic ring fixations are often necessary to maintain the stability of the pelvic ring and to achieve similar biomechanical properties to a normal pelvisThe fixation methods for posterior and anterior pelvic ring injuries include external fixation, open reduction and internal fixation with plates, and minimally‐invasive percutaneous sacroiliac screw fixation and pubic ramus screw fixationMinimally‐invasive surgery is a current trend in modern medicine. Robot‐centered technology for precision orthopaedic treatments has become one of the major directions in the development of surgical techniquesMinimally‐invasive fixation using combined sacroiliac and anterior column screw placements is an alternative surgical approach to the treatment of anterior and posterior pelvic ring fracturesChina owns the complete intellectual property rights for the “TianJi” robotic system, which was independently developed as a “Key Research and Development of Digital Diagnosis and Treatment” project of the Ministry of Science and Technology in China for use during orthopaedic surgery procedures. The third‐generation orthopaedic surgery robot TiRobot represents the latest generation of versatile state‐of‐the‐art robot‐based navigation systems for orthopaedic surgery. This robotic system adopts a modularized, miniaturized, and generalized designWe identified patients who underwent robot‐assisted minimally‐invasive internal fixations of pelvic fractures and analyzed the surgical plans selected for different types of pelvic ring injures. The purposes of this study were: (i) to investigate the indications and contraindications for robot‐assisted internal fixations of pelvic ring injures; (ii) to analyze the safety and efficacy of the surgery; and (iii) to discuss surgical strategy, techniques, precautions, and existing problems with robot‐assisted surgery for pelvic ring injures.The inclusion criteria were: (i) closed, unstable pelvic ring injuries (Tile type B or C fractures), with or without fracture displacement, that could easily be treated with closed reduction (or limited open reduction), after which a bone tunnel was available for cannulated screw placements; (ii) patients with closed Tile type A2 fracture who could not tolerate bedridden or required early movement; and (iii) patients with fixable open Tile type B and C fractures that became closed fractures after initial treatment and were eligible for reduction and screw placements. Exclusion criteria were: (i) presence of severe open injuries or rupture of the abdominopelvic cavity and organs with wound contamination; (ii) unstable hemodynamics; (iii) tissues such as blood vessels and nerves in the robot‐planned trajectory that could not be avoided, or patients without a bone tunnel for cannulated screw placement after reduction, or patients with fractures in which effective screw fixation could not be achieved; (iv) hardware or patient factors resulting in poor image acquisition and failure to safely conduct procedure planning; (v) poor condition of local skin, or infection of the soft tissues at or around the screw insertion site; (vi) systemic diseases such as severe bleeding disorders, severe heart disease, and severe respiratory disease; and (vii) inability to tolerate anesthesia or surgery.This retrospective study reviewed a case series from November 2016 to May 2018. The study protocol was approved by our Institutional Review Board. Informed consent was obtained from all participants included in the study. A total of 86 patients with anterior and posterior pelvic ring injuries (including nine acetabular or iliac wing fractures) underwent robot‐assisted internal fixations at the author's (L. Huashui's) institution. The study population included 57 men and 29 women, with an average of 40.2 ± 13.6 years . There were 71 closed fractures, 15 open fractures that became closed fractures after initial treatment, and 47 combined non‐severe injuries in other body locations. According to the Tile classification, there were 5 type A2, 48 type B, and 33 type C fractures. All operations were performed by the same team of surgeons who possessed adequate clinical experience in orthopaedic traumatology.After admission, the patients’ vital signs were monitored, venous access was established, and comprehensive and focused physical examinations were conducted. Patients were also given urethral catheterization and blood volume expansion therapy. Patients with unstable hemodynamics were treated with temporary pelvic external fixation. Patients with vertical instability were treated with lower extremity traction. Routine imaging of the pelvis was performed using X‐ray, CT scans, and 3D reconstructions. After initial treatment, follow‐up radiographs were obtained when the patients became hemodynamically stable. The surgical plans were formulated based on the injury type of the pelvic ring, the effectiveness of the reduction, and the availability of bone tunnels. Most surgeries were performed between days 3 and 14  after initial injury.The TiRobot system, the third generation TianJi robot for orthopaedic surgery , is composed of a main console, a robotic arm, surgical planning and controlling software, an optical tracking system, a main control workstation, and a navigation and positioning toolkit. Additional surgical equipment included a C‐arm X‐ray machine , ϕ7.3‐mm cannulated screw and ϕ6.5‐mm pedicle screw systems , and reconstruction locking plates .The surgical strategy is presented in Table During the surgical procedures, patients were administered general anesthesia with tracheal intubation after being placed in the supine position. The surfaces were sterilized by routine disinfection and draping. A tracker was fixed on the contralateral anterior superior iliac spine. Then, a sterile working environment for the robotic arm was established by assembling and fixing the robot tracker and the sterile protective sleeve. After installing the calibrator for the robot tracker, the surgeon moved to an appropriate position on the ipsilateral side near the operating bed to initiate the support systems and to lock the position of the robot. Images of the pelvic fractures corresponding to each surgical procedure were taken using a fluoroscope fixed with a calibrator. The fluoroscopic images were then transmitted to the robotic planning system. Based on the patient's anatomic features and the fracture conditions, the surgeon designed the instructions using the planning system and completed the simulation of the cannulated screw placement on the images. After a plan was established, the robotic arm began to move according to the instructions. The guidance in the pre‐planned trajectory was completed outside the body using guidewires and sleeves. The skin was incised, and the subcutaneous layer was separated. The sleeve was placed onto the bone surface, and the trajectory was recalibrated. The guiding needle was inserted along the trajectory and the cannulated screws were then inserted along the needle. The positioning of the cannulated screws was verified by fluoroscopy. The wound was subsequently rinsed, the subcutaneous layer and skin were sutured, and the surgery was completed.Prophylactic antibiotics were used for 48 h after surgery. Low‐molecular weight heparin calcium was used for 4 weeks for prevention of deep vein thrombosis treatment. Follow‐up imaging of X‐ray and CT scan were performed 72 h after fixation. Postoperative rehabilitation training was conducted according to the patient's injury severity, fracture type, and methods used for internal fixation. For patients with isolated pelvic injuries and satisfactory internal fixations, stretching exercises of the hip and knee joints could be performed after recovering from anesthesia. Two days after surgery, the patients were allowed to perform moderate exercises that involved body turning. The exercise intensity could be gradually increased for patients with combined injuries. Patients with an isolated anterior pelvic ring injury were allowed to get out of bed and start walking with the help of crutches at 1 week after surgery. The timing for patients with combined anterior and posterior pelvic ring injuries to get out of bed and perform weight‐bearing activities was based on the severity of their injuries and the fracture healing process. Generally, these patients could begin walking with two crutches 2–4 weeks after surgery, walk with one crutch and lean on the contralateral leg in 5–7 weeks, and then walk with full weight‐bearing in 8–10 weeks. The process for patients with severe injuries was delayed by 2 weeks.The surgical complications, especially for the penetration accidents resulting from needle deviation, were recorded. All patients were available at a mean follow‐up of 4.2 months (3–6 months). The patients received monthly follow‐up pelvic radiographs until the fractures were healed. The position and accuracy of the robot‐assisted screw placements were evaluated according to the radiographic data of the last follow‐up. During the follow‐up period, patients were queried as to their daily activities, pain levels, standing difficulties, and walking distances to determine their tolerance to the screws inserted during the internal fixation procedure. Evidence for wound infection, screw loosening, and nerve injury was evaluated. Patients with nerve injuries were treated with neurotrophic drugs. The dressings were changed more frequently in patients with wound infections. Efficacies were evaluated according to the Majeed score.According to the type of pelvic ring injuries, 5 patients with isolated anterior pelvic ring injuries were treated with robot‐assisted percutaneous cannulated screw fixation of the pubic ramus, 6 patients with posterior pelvic ring injury combined with symphysis pubis separation were treated with robot‐assisted percutaneous cannulated sacroiliac screw fixation and open screw or plate fixation of the symphysis pubis, 32 patients with posterior pelvic ring injury combined with unilateral anterior pelvic ring injury were treated with robot‐assisted percutaneous cannulated sacroiliac screw fixation pubic ramus screw fixation, and 43 patients with posterior pelvic ring injury combined with bilateral anterior pelvic ring injury were treated with cannulated screw fixation alone (11 cases), INFIX fixation (19 cases), and “hybrid surgery” (13 cases). Among these patients, 21 with unsatisfactory reduction of displaced fractures underwent closed reduction or limited open reduction under anesthesia to restore the normal anatomic structures and to establish a bone tunnel for screw placements; 13 complex anterior pelvic ring injury patients with difficult reductions required “hybrid surgery.”A total of 274 screws were inserted with robotic assistance, of which 262 screws were successfully inserted to a satisfactory position on the first attempt. The average number of screws inserted per patient was 3.2. The average operative time was 175 ± 32.6 min . The average length of the incisions in which the screws were inserted was 2 cm. The average intraoperative blood loss during the robotic procedure was 35.2 ± 3.6 mL  and the average blood loss during hybrid surgery was 270 ± 156.7 mL . The screws inserted with robotic assistance were exposed to radiation an average of 29.1 ± 10.5 times  during the surgery. The total fluoroscopy time was 6–42 s, and the average fluoroscopy time for each screw was 6.1 ± 0.2 s.There were 13 unsatisfactory intraoperative guiding needle placements, including 5 with obvious needle deviations that remained in the bone tunnel (re‐planning for screw placement was not performed), and 8 with cutting or penetration of the cortex.As shown in Table In 1 posterior pelvic ring surgery, the guiding needle penetrated the sacral foramen and caused sacral nerve injury. In 1 open INFIX fixation, the lateral femoral cutaneous nerve was injured. Both patients’ injuries and symptoms resolved after treatment with neurotrophic drugs.All wounds after robot‐assisted surgeries were healed by primary intention. After the “hybrid surgery” cases, there was 1 case of (subcutaneous) wound infection, 1 case of necrosis along the skin wound edges, and 1 case of ecchymosis. The ecchymosis disappeared spontaneously within 2 weeks, and the subcutaneous infection and skin necrosis resolved after changing the dressing.Postoperative imaging revealed that the pelvic rings were in good shape. The CT scans showed that all sacroiliac screws inserted under robotic assistance were located within the boundary of the sacrum. There were no anterior or posterior edges observed on the sacrum, sacral canal, or sacral foramen. The pubic ramus screws were all located within the bone tunnel of the symphysis pubis with no penetration of the anterior–posterior or superior–inferior edges of the pubis. The positions of the sacroiliac screws were assessed as LonsteinAll patients’ fractures healed within 3 months of surgery except for 2 patients with fixation failures who underwent secondary surgeries. One patient with combined posterior pelvic ring injury and symphysis pubis diastasis was treated with steel plate fixation of the anterior pelvic ring, but the fixation failed because of loosening of the screws. Secondary fixation using a steel plate was performed. In 1 case  of INFIX fixations, the symphysis pubis was separated again, and plate fixation was performed instead.All robotic‐assisted screw insertions were neither loose, displaced, nor broken, and the patients’ postoperative lower limb functions were normal. The 19 patients who underwent anterior pelvic ring INFIX fixations tolerated the procedures without difficulty. Five patients with slim body types experienced local irritation from the pedicle screw tips, and the INFIX devices were removed after 12 weeks.According to the Majeed score classification, 57 cases obtained excellent results, 26 good, and 3 fair. The average score was 92.4 points at the last follow‐up. The 3 fair cases were all severe injuries with poor reduction patients, included 1 case of hybrid surgery and 2 cases of INFIX fixation.Typical cases are shown in Fig. Robot surgery is characterized by small trauma, quick recovery, and good technical, economic and social benefits. Precision medicine with robot technology at the core is the future development direction of orthopaedics. At present, in China, our center has carried out a relatively large number of robot‐assisted pelvic surgeries and accumulated some experience. Here, the authors discuss some of the issues faced in carrying out this operation.Robot‐assisted percutaneous cannulated screw fixation of the pubic ramus or robot‐assisted percutaneous cannulated screw fixation of the sacroiliac joint may be used in the management of isolated anterior or posterior pelvic ring injuries.Isolated anterior pelvic ring injury is commonly seen in clinical practice. Straddle injuries can lead to anterior pelvic ring injuries. This study included 5 patients with isolated  anterior pelvic ring injuries. In principle, a conservative treatment approach can be adopted for anterior pelvic ring fractures without displacement or with only minor displacement. However, elderly patients, patients who cannot tolerate long‐term bed rest, and patients who require early movement can be actively treated using robot‐assisted minimally‐invasive percutaneous pubic ramus screw fixation according to the relative surgical indications. Intraoperative images of the obturator outlet, the pelvic inlet, and the pelvic anteroposterior view should be acquired to complete surgical planning, trajectory positioning, and screw insertions.Isolated posterior pelvic ring injuries are rare in clinical practice. Posterior pelvic ring injuries should be managed with robot‐assisted sacroiliac screw fixations. Intraoperative images should be taken in the following order: pelvic inlet, pelvic outlet, and lateral view of the pelvis. Finally, the images should be used to guide trajectory planning and screw insertions.Combined anterior and posterior pelvic ring injury is the most common type of pelvic fracture, and is primarily characterized by unstable pelvic fractures that require a combined fixation of both the anterior and posterior pelvic rings. Combined anterior and posterior pelvic ring injuries can be classified into three types:Robot‐assisted percutaneous cannulated screw fixation of the sacroiliac joint may be used to manage the posterior pelvic ring, and open screw or plate fixation of the symphysis pubis may be used to manage the anterior pelvic ring (hybrid surgery). For patients with symphysis pubis diastasis >2.5 cm, open reduction should be performed in the anterior pubis. Steel plate fixation is recommended to maintain reliable mechanical strength. Fixation of the anterior pelvic ring should be performed first, followed by fixation of the posterior pelvic ring.Robot‐assisted percutaneous cannulated screw fixation of the sacroiliac joint may be used for the posterior pelvic ring, and robot‐assisted percutaneous cannulated screw fixation of the pubic ramus may be used for the anterior pelvic ring. The surgical order is irrelevant if the reduction is satisfactory.This type of injury may be treated in three ways:Cannulated screw fixation alone. Robot‐assisted  percutaneous cannulated screw fixation of the sacroiliac joint may be used for the posterior pelvic ring, and robot‐assisted  percutaneous cannulated screw fixation of the pubic ramus may be used for the anterior pelvic ring. This approach is only suitable for fractures without obvious displacement or fractures that are easily reduced and have been treated successfully with screw fixation. Intraoperatively, the tracker should be alternately fixed for the trajectory planning of the bilateral pubic ramus and sacroiliac screws.Combined cannulated screw fixation of the posterior pelvic ring and anterior pelvic ring INFIX fixation. This approach is more suitable for obese patients with “open book‐like injuries.” The integrity of the pelvic ring can be properly restored using a connecting rod. Therefore, fixation should be used to treat the posterior pelvic ring first, followed by the anterior pelvic ring. The INFIX pedicle screws can be placed manually or under robotic assistance. The latter involves acquiring LC‐2 front view and iliac oblique view images for trajectory planning, which is more accurate than freehand screw insertions and can reduce damage to the subcutaneous soft tissue. After INFIX fixation is performed in the anterior pelvic ring, the posterior pelvic ring can be treated using conventional robot‐assisted percutaneous cannulated screw fixation of the sacroiliac joint.INFIX causes little trauma, has minimal impact on patients’ daily life, and is particularly useful in obese patients“Hybrid surgery”: Combined robot‐assisted sacroiliac screw fixation of the posterior pelvic ring and open reduction and internal fixation of the anterior pelvic ring. Traditional open reduction surgery has many disadvantages, including the requirement for large incisions, significant stripping and damage to soft tissues, and bleeding. However, closed reductions are difficult to perform for complex “open book‐like injuries” and “mixed injuries.” Therefore, among patients with fractures in whom effective screw fixation cannot be achieved after open reduction, a traditional open reduction and internal fixation approach can be used as a last resort. The Stoppa approach or the ilio‐inguinal approach can be used.(Combined) acetabular fractures and/or iliac wing fractures. Pelvic fractures often occur in combination with acetabular or iliac wing fractures. In principle, pelvic ring injuries require functional reduction and correction of alignment for relative stability, whereas acetabular fractures require anatomic reduction and absolute stability. In cases of combined acetabular fractures, patients with a relatively small total displacement of the articular surface that can be easily reduced may be treated with robot‐assisted minimally‐invasive cannulated screw fixation in the anterior column after reduction. Iliac wing fractures do not affect the pelvic ring and the requirement for stability is low. These fractures can be treated with robot‐assisted screw fixation or open reduction and internal fixation under direct vision. Even though complete anatomic reduction is not achieved, satisfactory postoperative clinical outcomes can be achieved.The domestically‐developed orthopaedic surgery TiRobot from China uses a unique two‐plane positioning algorithm to complete the spatial positioning and adopts a modular design to facilitate the navigation of the surgical trajectory. The system is precise with respect to screw placement, with a positioning accuracy of 1 mm. Experimental research on robot‐assisted sacroiliac screw fixationThe use of robots in orthopaedic surgery theoretically eliminates the instability introduced by surgeons during manual operations. Compared with open/manual surgery, the screws inserted via robotic assistance deviate less from the pre‐planned positions and also have lower needle penetration rates. In this study, a total of 274 screws were inserted under robotic assistance, of which 262 screws were successfully inserted into satisfactory positions on the first attempts. The success rate of one‐time screw placement was extremely high and the surgery was safe. Secondary injuries caused by deviation of the needle path and needle penetration occurred, which might be due to slippage of the needle tip, lateral stress, and surgeon error. However, robotic surgery has achieved unparalleled precision and safety compared to manual screw insertions.A good reduction that restores the continuity and integrity of the bone tunnel is a prerequisite for screw placement. Patients with unstable combined anterior and posterior pelvic ring injuries who are also hemodynamically unstable prior to surgery (postadmission) should first be treated with external temporary fixations. Patients with vertical instability should be treated with lower extremity traction to correct the vertical displacement. Patients with unsatisfactory reductions can be treated with closed or open reductions. For pubic ramus fractures that are difficult to treat with closed reduction and those with displacements exceeding 10 mm, a small incision can be made using reduction forceps to reduce the fracture at its anterior end under fluoroscopic guidance until the reduction is satisfactory. Patients with sacral displacements >10 mm who do not show significant improvement after traction can be treated with posterior lumbo‐iliac screws and a rod to assist the reduction.Currently, it is not feasible for a robot to complete all surgical procedures. The guiding needle and screw placements still need to be performed manually and cannot be monitored in real time. In addition, the screw placement process could injure the patient if the operators’ experience level is insufficient. To reduce subcutaneous damage and to avoid secondary damage caused by needle path deviation, the screw placement should be performed with adherence to the following: (i) the surgeon must be familiar with the patient's anatomy to avoid vascular and nerve damage, and repeated screw placement should be avoided to reduce damage to subcutaneous soft tissues; (ii) excessive traction should be avoided when opening channels in the soft tissue to reduce lateral stress; (iii) during sleeve insertion and as soon as the sleeve contacts the bone surface, the surgeon should pull in the opposite direction based on the needle insertion point to offset the gliding caused by the slanted bone surface; (iv) during guiding needle insertion, the electric drill should be reversed to avoid exerting excessive pressure on the bone surface, which is particularly useful when the guiding needle contacts the bone surface, as it can reduce gliding caused by the slanted bone surface; and (v) the surgeon must monitor the procedure attentively and act in a timely manner; if the cortex is penetrated, the needle should be withdrawn immediately and the direction should be adjusted with re‐planning of screw placement as needed to ensure the guiding needles and screws are located completely within the bone tunnel. Finally, these operations should only be performed by experienced surgeons or with experienced surgeons in attendance.During robotic surgery, the operating environment should meet the regular working requirements specified in the robotic surgery manual. The operating room should be of suitable size with a good grounding system and power supply conditions. The operating table should meet the requirements for positioning and image acquisition. Surgeons in these cases must be experienced in the traditional surgical methods and skilled at closed reduction and internal fixation procedures. They must also possess the relevant anatomical knowledge to determine the accuracy of the navigation system and have the ability to switch to traditional surgery if there are hardware or software robotic system failures or sudden complications that preclude continuation of the robotic surgery. The surgeon must be familiar with the basic principles of the robotic system. They should complete robotic image acquisition accurately and plan the surgery based on scientific principles. This can ensure a smooth operation, reduce the “noninvasive time,” and shorten the overall operative time. For image acquisition, all bone structures in the operative area must be included, the bone tunnel should be continuous and complete, the calibrator should be clearly presented in fluoroscopic view, and the optical tracking camera should simultaneously recognize and capture the spatial position data from the patient tracker and the robot tracker. To avoid blurred images, the tracker position should be monitored closely during surgery, minimizing any factors that might interfere with the tracker, which will avoid loosening and shifting of the tracker and reduce error. The operation should be performed gently to avoid large relative displacements between the bone structures. Changes in the patient's position may cause changes in the spatial positions of the anatomic structures, resulting in a shift in the relative position between the patient and their tracker. If the angle between the guiding needle and the bone surface is too small, it could lead to incomplete fixation at the entry point and gliding of the needle tip, which will inevitably result in errors. Insertion of the guiding device and needles may deviate under excessive lateral stress if the sleeve is too long. Currently, this surgery cannot be performed under full robotic control. The surgeon is required to complete the screw placement trajectory planning according to the anatomic features and the fracture conditions using the software. Placement of the guiding needles and screws should be performed manually. Because it is not feasible to monitor the whole process, the surgeon must have a certain level of experience; however, subjective and operational errors may still occur.This study is only a summary of the experience in our center without subdivision of the types of fracture injuries. At present, few centers can perform robot‐assisted pelvic surgery with an orthopaedic surgery robot, and no standards are available for robot‐assisted minimally‐invasive pelvic fracture treatment in China. For the next step, multi‐center controlled studies should be carried out, the strategies and skills of this surgery should be further investigated, and guidelines for robot‐assisted minimally‐invasive pelvic fracture treatment should be developed, so as to finally standardize the procedures and promote the popularity of this surgery.Most surgical techniques are being assessed from the perspective of performance using minimally‐invasive approaches. The application of the high‐end innovative robot, independently developed and made in China, for orthopaedic surgery provides a novel approach to the minimally‐invasive treatment of pelvic fractures. This study highlights an improvement in China's capability as a leader in the medical diagnosis and treatment of pelvic fractures. Rigorous selection of patients based on suitable indications, standardization of operating procedures, and assurance of surgical quality, along with appropriate surgical rationale and procedural efficacy, will surely allow the precise robotic approach to gain popularity and become widely adopted, which will benefit a vast number of orthopaedic patients.


Botswana has among the highest level of HIV viral suppression globally, yet HIV incidence remains > 1% per year in adults aged 15 to 49 There is precedent for providing government‐sponsored HIV treatment to non‐citizens in Botswana. In 2014, a court ruling found that denying non‐citizens in prison access to ART violated their right to receive basic health services, as guaranteed by the Botswana Constitution Only citizens are accounted for in national estimates of people living with HIV, HIV incidence and treatment outcomes, leaving the impact of the HIV epidemic among immigrants largely hidden. Understanding the HIV epidemic in the immigrant population may inform considerations in expanding treatment coverage, and may ultimately help Botswana achieve greater viral suppression, and reduce HIV incidence throughout the population.How many non‐citizen immigrants reside in Botswana?What is the HIV prevalence in this population, and what proportion of non‐citizens living with HIV are on ART?What are the barriers to HIV testing, linkage‐to‐care or retention, and viral suppression among non‐citizen, and how do these compare to citizens?As Botswana considers joining regional neighbours such as South Africa and Lesotho in developing national HIV treatment policies that include non‐citizens To encourage thought on the subject, we performed a preliminary review of published literature addressing each of these essential questions. Broadly, we found the published literature on these questions far too limited to properly examine an important change in national HIV treatment policy. Here, we summarize the results of the four questions posed, and identify the largest gaps within each question. Although some data sources distinguish between the documentation status of non‐citizens, this is non‐universal so unless otherwise stated, we refer here to all non‐citizens.1Two published reports were available to estimate the number of non‐citizens in Botswana. The United Nations estimated that 166 thousand non‐citizens resided in Botswana in 2017, about half of whom were from South Africa, Zimbabwe and Zambia, countries with high HIV prevalence 2p < 0.001) Data from the Botswana Combination Prevention Project (BCPP) suggested that within 30 rural and peri‐urban communities throughout Botswana, the prevalence of HIV among citizens and non‐citizens was approximately equal (20% vs. 22% respectively) p < 0.001). These results, however, are still limited by their lack of data from urban settings. The only published data available highlighting ART access and treatment outcomes in an urban setting are from the Maipelo Trust clinic in Gaborone, which reported slower ART initiation, fewer viral load tests, reduced viral suppression and higher mortality among non‐citizens compared with citizens The BCPP also found that only 29% of non‐citizens with known HIV‐positive status were enrolled on ART, compared to 71% of citizens (3Migrant populations throughout the world often experience stigma while accessing health services, with Botswana serving as no exception. Immigrants fleeing economic collapse in Zimbabwe bear much of this burden, as they are frequently the target of xenophobia and stigma from Batswana Substantial research is needed to inform potential expansions in non‐citizen testing and treatment coverage. Data may be needed prior to significant policy changes since Botswana already self‐funds at least two‐thirds of its HIV response, and further strain on the country's programme capacity may be detrimental without increased donor input The authors declare they have no conflicts of interest.DJE and TM performed the literature review, drafted the original manuscript and revised the manuscript based on peer review. DJE, TM, AM, JM and GRS evaluated the results of the literature review and provided critical edits to the manuscript. All authors approved the final manuscript.


Marine protected areas (MPAs) are a critical defense against biodiversity loss in the world's oceans, but to realize near‐term conservation benefits, they must be established where major threats to biodiversity occur and can be mitigated. We quantified the degree to which MPA establishment has targeted stoppable threats  by combining spatially explicit marine biodiversity threat data in 2008 and 2013 and information on the location and potential of MPAs to halt threats. We calculated an impact metric to determine whether countries are protecting proportionally more high‐ or low‐threat ecoregions and compared observed values with random protected‐area allocation. We found that protection covered <2% of ecoregions in national waters with high levels of abatable threat in 2013, which is ∼59% less protection in high‐threat areas than if MPAs had been placed randomly. Relatively low‐threat ecoregions had 6.3 times more strict protection  than high‐threat ecoregions. Thirty‐one ecoregions had high levels of stoppable threat but very low protection, which presents opportunities for MPAs to yield more significant near‐term conservation benefits. The extent of the global MPA estate has increased, but the establishment of MPAs where they can reduce threats that are driving biodiversity loss is now urgently needed. However, the primary objective of all PAs with an IUCN category is to conserve nature Dudley , and theWe used the most comprehensive data on cumulative global marine threats in 2008 and 2013   from the cumulative human impact data by Halpern et al. . We cateOur framework was built around the goals of MPAs in international conservation agreements and the IUCN definition of PAs Dudley , which iWe assessed the current state of MPA establishment in relation to stoppable threats by comparing the proportion of total area protected with mean stoppable threat in each ecoregion in 2013 and comparing the change in area protected between 2008 and 2013 with mean stoppable threat in 2008. Each ecoregion was classified into 1 of 16 categories based on the quartiles of the proportion of area protected and the level of stoppable threat across all ecoregions  for country (C) is calculated aspH is the area protected in high‐threat ecoregions, pL is the area protected in low‐threat ecoregions, aH is the area of high‐threat ecoregions, and aL is the area in low‐threat ecoregions within each country. The metric is bounded between −1, if only low‐threat ecoregions are protected, and 1, if only high‐threat ecoregions are protected, and results in a value of 0 if high and low‐threat ecoregions are proportionally protected equally. These upper and lower bounds facilitate comparison between countries. The metric itself is useful because it accounts for dependence of the amount of protection in either threat category on the total area of ecoregions within that category. Therefore, a country is not penalized for having less or more area with relatively high levels of stoppable threat. Due to potential costs of establishing MPAs in high‐threat areas and patterns of terrestrial PA trends of avoiding areas of commercial value . We recalculated the level of protection and the level of stoppable threat within each country's ecoregions. Protection within ecoregions was classified as avoiding threats (protection in low‐threat ecoregions) or targeting threats (protection in high‐threat ecoregions). To increase transparency in reporting, we calculated an impact metric based on the difference between the proportion of protection in high‐threat ecoregions and the proportion of protection in low‐threat ecoregions . Our impact metric was adapted from the conversion‐to‐protection ratio that was developed to calculate global disparities of habitat loss and protection in terrestrial systems  and allocated area equal to the median PA size within that country until the total area protected in 2013 was reached (Supporting Information). The median value was used because it is more robust to outliers. We ensured the proportion of area protected in each ecoregion never exceeded 1 and calculated the impact metric as above. This was repeated 1,000 times. The random impact metric was equal to the average impact metric across all simulations. Our null hypothesis was that countries protect area randomly  and thus observed and random impact metrics would be similar. An observed impact metric that was outside the 95% confidence interval (CI) of the mean random impact metric was considered significantly different than random. If the distribution of the random impact metric across all simulations was not normal, a bootstrap confidence interval was generated using the boot package in R (version 3.3.3)   exhibited positive impact indices  (Supporting Information).Poorly protected ecoregions  occurred across 134 countries. We identified 33 low‐risk (lowest quartile), 23 moderate‐risk, 29 high‐risk, and 31 crisis (highest quartile) ecoregions  will be imperative to maximize the conservation impact of future MPA expansion through local‐scale implementation. For example, areas with high threat may also be more costly to protect in terms of opportunity costs . Transboundary initiatives are becoming more prevalent in the global PA estate, but can be complex and challenging to implement  areas, almost by definition, are irreplaceable  in perpetuity  can be attributed to fishing pressure, which is unsurprising considering fishing is one of the most pervasive immediate threats to marine biodiversity  that spIt is clear that the current areal approach to measuring conservation progress masks biases in MPA designation relative to threat, thereby undermining the goal of international conservation agreements to “safeguard ecosystems, species, and genetic diversity” , a theoretical depiction of the impact metric (Appendix S2), global protection and threat classifications by IUCN category (Appendix S3), the threat classification scheme (Appendix S4), country‐level summary statistics (Appendices S5 and S6), and transboundary country results (Appendix S7) are available online. The authors are solely responsible for the content and functionality of these materials. Queries  should be directed to the corresponding author.Click here for additional data file.


Exosomes are endosomal‐derived membrane‐confined nanovesicles secreted by many  cell types and isolated from every human bodily fluid examined up to now including plasma, semen, vaginal secretions and breast milk. Exosomes are thought to represent a new player in cell‐to‐cell communication pathways and immune regulation, and be involved in many physiological and pathological processes. Susceptibility to HIV‐1 infection can be impacted by exosomes, while HIV‐1 pathogenesis can alter exosomal function and composition. Exosomes isolated from semen and vaginal fluid of healthy individuals can inhibit HIV‐1 infection and/or potently block viral transfer in vitro. However, the role of exosomes in HIV‐1 transmission and progression is not fully understood yet and some studies show conflicting results, mainly for exosomes isolated from plasma and breast milk. Determining the composition of exosomes from infected donors and studying their interaction with HIV‐1 in vitro compared to exosomes isolated from uninfected donors will provide insights into the role exosomes play in HIV‐1 transmission during sexual intercourse and breastfeeding. Transmission electron microscopy analysis of SE samples has shown that they are composed of lipid bilayer particles in the characteristic size range of exosomes and nanovesicles from other cellular sources. SE have also been shown to express the universal exosome markers heat shock protein (HSP)‐70 and CD63, but not ER calnexin indicating that the vesicles are coming from non‐endoplasmic reticulum sources  from infected individuals come in contact with the genital and colorectal mucosae of uninfected partners. The contribution of SE in semen‐induced mucosal immune responses and impact on HIV‐1 sexual transmission are suspected, but have yet to be properly characterised. One hypothesis is that HIV‐1 infection changes the immunosuppressive function of SE, thus enabling SE from HIV‐1‐infected individuals to promote HIV‐1 sexual transmission and impair the induction of a protective immune response against the infecting virus. This functional shift in SE may be due to hijacking of exosomal pathways by viral proteins, such as HIV‐1 Nef, resulting in a reduced ratio of exosomal versus host cell viral binding sites, which would enhance HIV‐1 entry into target cells  and exosomes  and co‐incubated for 3 days. These contradictory data may be the result of differences in exosome collection and purification or experimental design. This caveat also applies to many of the discrepant results reported on the functional role of exosomes.Conflicting reports have been published on exosomes isolated from human breast milk from healthy donors. Indeed, pre‐exposure to exosomes purified from human breast milk inhibits HIV‐1 infection mediated by dendritic cells (DC) by binding to DC‐SIGN, and blocking transport and transfer of virus to target CD4The impact of SE, VFE, plasma, and breast milk exosomes on HIV‐1 infection/transmission is summarised in Table 6While SE of uninfected individuals have been reported to have the ability to modulate HIV‐1 transmission in vitro, the properties of SE isolated from HIV‐1‐infected patients in acute and chronic stages of the infection have not been fully explored. This represents a critical gap in the knowledge since, globally, HIV‐1 transmission occurs predominantly through sexual transmission. While there is evidence showing that plasma‐derived exosomes from HIV‐1 infected individuals differ in composition and function compared to those from uninfected individuals, the immunomodulatory effect of SE from HIV‐1 seropositive versus seronegative individuals has not been characterised. Given the high amount of SE being delivered to the relatively limited surface area of the CV mucosa and the fact that SE contain abundant cytokines, chemokines, miRNA and mRNA codifying for antiviral factors (Vojtech et al., We speculate that exosomes isolated from vaginal fluid and seminal plasma from healthy participants may be used as a model for potential HIV‐1 preventative and therapeutic agents. Delivery systems with exosomal nanoparticles containing anti‐HIV‐1 effectors could be designed and potentially used as therapeutic agents for HIV‐1 prevention and/or treatment. Virus propagation and plasma viraemia were reduced in mice inoculated with a mix of virus and exosomes, suggesting a possible therapeutic function of SE isolated from healthy donors on mucosal and systemic HIV‐1 transmission (Madison et al., 7Exosomes mediate important cell‐to‐cell communication and, in HIV‐1 infection, this occurs through the exosomal delivery of the viral and host molecules, which vary greatly depending on their cellular source. Exosomes derived from semen of healthy donors can suppress HIV‐1 infection in vitro and decrease intravaginal replication of mAIDS virus. Similarly, exosomes isolated from vaginal fluids can inhibit early steps of HIV‐1 infection. To date, however, the structural and functional properties of SE isolated from HIV‐1 infected subjects have not been reported. Consequently, the exact role of seminal exosomes in HIV‐1 transmission has not been clearly defined, representing a gap in the knowledge and a focus of research with high potential for impact.