Combined analyses of within-host SARS-CoV-2 viral kinetics and information on past exposures to the virus in a human cohort identifies intrinsic differences of Omicron and Delta variants.

The emergence of successive Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) during 2020 to 2022, each exhibiting increased epidemic growth relative to earlier circulating variants, has created a need to understand the drivers of such growth. However, both pathogen biology and changing host characteristics-such as varying levels of immunity-can combine to influence replication and transmission of SARS-CoV-2 within and between hosts. Disentangling the role of variant and host in individual-level viral shedding of VOCs is essential to inform Coronavirus Disease 2019 (COVID-19) planning and response and interpret past epidemic trends. Using data from a prospective observational cohort study of healthy adult volunteers undergoing weekly occupational health PCR screening, we developed a Bayesian hierarchical model to reconstruct individual-level viral kinetics and estimate how different factors shaped viral dynamics, measured by PCR cycle threshold (Ct) values over time. Jointly accounting for both interindividual variation in Ct values and complex host characteristics-such as vaccination status, exposure history, and age-we found that age and number of prior exposures had a strong influence on peak viral replication. Older individuals and those who had at least 5 prior antigen exposures to vaccination and/or infection typically had much lower levels of shedding. Moreover, we found evidence of a correlation between the speed of early shedding and duration of incubation period when comparing different VOCs and age groups. Our findings illustrate the value of linking information on participant characteristics, symptom profile and infecting variant with prospective PCR sampling, and the importance of accounting for increasingly complex population exposure landscapes when analysing the viral kinetics of VOCs. Trial Registration: The Legacy study is a prospective observational cohort study of healthy adult volunteers undergoing weekly occupational health PCR screening for SARS-CoV-2 at University College London Hospitals or at the Francis Crick Institute (NCT04750356) (22,23). The Legacy study was approved by London Camden and Kings Cross Health Research Authority Research and Ethics committee (IRAS number 286469). The Legacy study was approved by London Camden and Kings Cross Health Research Authority Research and Ethics committee (IRAS number 286469) and is sponsored by University College London Hospitals. Written consent was given by all participants.

The Hidden Hand of Asymptomatic Infection Hinders Control of Neglected Tropical Diseases: A Modeling Analysis.

BACKGROUND: Neglected tropical diseases are responsible for considerable morbidity and mortality in low-income populations. International efforts have reduced their global burden, but transmission is persistent and case-finding-based interventions rarely target asymptomatic individuals. METHODS: We develop a generic mathematical modeling framework for analyzing the dynamics of visceral leishmaniasis in the Indian sub-continent (VL), gambiense sleeping sickness (gHAT), and Chagas disease and use it to assess the possible contribution of asymptomatics who later develop disease (pre-symptomatics) and those who do not (non-symptomatics) to the maintenance of infection. Plausible interventions, including active screening, vector control, and reduced time to detection, are simulated for the three diseases. RESULTS: We found that the high asymptomatic contribution to transmission for Chagas and gHAT and the apparently high basic reproductive number of VL may undermine long-term control. However, the ability to treat some asymptomatics for Chagas and gHAT should make them more controllable, albeit over relatively long time periods due to the slow dynamics of these diseases. For VL, the toxicity of available therapeutics means the asymptomatic population cannot currently be treated, but combining treatment of symptomatics and vector control could yield a quick reduction in transmission. CONCLUSIONS: Despite the uncertainty in natural history, it appears there is already a relatively good toolbox of interventions to eliminate gHAT, and it is likely that Chagas will need improvements to diagnostics and their use to better target pre-symptomatics. The situation for VL is less clear, and model predictions could be improved by additional empirical data. However, interventions may have to improve to successfully eliminate this disease.

The development of social capital in a peer-led mHealth cognitive behavioral antiretroviral therapy adherence intervention for HIV + adolescents and young adults.

Adherence Connection for Counseling, Education, and Support (ACCESS)-I is a peer-led mHealth antiretroviral therapy adherence intervention for adolescents and young adults living with HIV who are in treatment but have detectable viral loads. Participants received five online sessions with peer health coaches who followed a structured intervention manual. Peers maintained intervention fidelity but also engaged in casual discussion that was not directly related to ART adherence or HIV. We conducted a qualitative analysis of the casual interactions that occurred during the ACCESS I intervention. Sessions were transcribed and coded, and these casual interactions were then coded into 10 subcodes to document their content, and also coded for three types of social capital - emotional, informational, and instrumental. Emotional and Informational social capital codes were the most common, while instrumental codes were rare. Activities was the most common topic overall, while encouragement was more common in emotional social capital narratives and personal experience was more common in informational social capital narratives. These casual interactions may strengthen peer-participant relationships, building social capital that could then be used to encourage positive behavior change. Although social capital was not directly measured, these analyses illustrate the value of attending to seemingly casual interactions in peer-led interventions.

A qualitative assessment of retention in HIV care among adolescents and young adults (AYA) living with HIV in New York City.

Retention in HIV care is a critical precursor to ending the epidemic yet remains suboptimal in the United States. Gaining an understanding of the challenges faced by adolescents and young adults (AYA) living with HIV is essential to improving retention in HIV care. This study explored the barriers and facilitators to retention in care among Black and Hispanic AYA living with HIV. Audio-recorded semi-structured interviews were conducted with 20 AYA living with HIV ages 16-29 years in New York City. Our methods entailed an inductive content analysis to explore key concepts, reconcile codes, and identify a theme, categories, and subcategories. Bronfenbrenner's socioecological model evolved as an organizing framework around barriers and facilitators to retention in care at the individual, interpersonal, healthcare system, and structural level. Data analysis yielded one overarching theme-the influence of psychosocial factors on retention in HIV care. Psychological struggles, powerlessness, clinic-level characteristics, and socioeconomic struggles were barriers reported by participants. Self-responsibility, social support, patient-friendly healthcare services, and socioeconomic resources emerged as facilitators. Retention in HIV care among AYA living with HIV is a multifaceted and complex phenomenon that involves multiple systems. Strengthening patients, healthcare system, and community partnerships can help address some of the HIV-related health disparities.

Predicting subnational incidence of COVID-19 cases and deaths in EU countries.

BACKGROUND: Recurring COVID-19 waves highlight the need for tools able to quantify transmission risk, and identify geographical areas at risk of outbreaks. Local outbreak risk depends on complex immunity patterns resulting from previous infections, vaccination, waning and immune escape, alongside other factors (population density, social contact patterns). Immunity patterns are spatially and demographically heterogeneous, and are challenging to capture in country-level forecast models. METHODS: We used a spatiotemporal regression model to forecast subnational case and death counts and applied it to three EU countries as test cases: France, Czechia, and Italy. Cases in local regions arise from importations or local transmission. Our model produces age-stratified forecasts given age-stratified data, and links reported case counts to routinely collected covariates (e.g. test number, vaccine coverage). We assessed the predictive performance of our model up to four weeks ahead using proper scoring rules and compared it to the European COVID-19 Forecast Hub ensemble model. Using simulations, we evaluated the impact of variations in transmission on the forecasts. We developed an open-source RShiny App to visualise the forecasts and scenarios. RESULTS: At a national level, the median relative difference between our median weekly case forecasts and the data up to four weeks ahead was 25% (IQR: 12-50%) over the prediction period. The accuracy decreased as the forecast horizon increased (on average 24% increase in the median ranked probability score per added week), while the accuracy of death forecasts was more stable. Beyond two weeks, the model generated a narrow range of likely transmission dynamics. The median national case forecasts showed similar accuracy to forecasts from the European COVID-19 Forecast Hub ensemble model, but the prediction interval was narrower in our model. Generating forecasts under alternative transmission scenarios was therefore key to capturing the range of possible short-term transmission dynamics. DISCUSSION: Our model captures changes in local COVID-19 outbreak dynamics, and enables quantification of short-term transmission risk at a subnational level. The outputs of the model improve our ability to identify areas where outbreaks are most likely, and are available to a wide range of public health professionals through the Shiny App we developed.

Culture-based stigmatizing attitudes toward condom use among Chinese older adults: An interpretative phenomenological analysis.

OBJECTIVE: To explore their perceptions and attitudes toward condom use and the underlying reasons for the low usage frequency among Chinese older adults. METHODS: A qualitative study design utilizing interpretive phenomenological analysis was employed. Data were collected through field observation and face-to-face in-depth interviews among older adults aged 50 years or above and having engaged in sexual activities within the previous year. RESULTS: Three main themes emerged: perceiving unnecessary due to misconceptions and low awareness, interactive stereotypes rooted in sociocultural beliefs, and stigmatized social norms including gender inequity and economic unbalance. CONCLUSIONS: Tailored interventions focusing on addressing misconceptions, increasing awareness, and reducing culturally ingrained stereotypes and stigma surrounding condom use are essential to promote condom use among older adults in order to prevent HIV transmission in China.

Food insecurity and its relationship to mental health and oral health in older adults.

BACKGROUND AND OBJECTIVES: Poor oral health disproportionately affects low-income older adults, for whom food insecurity and poor mental health may affect dental health. We explored the associations between food insecurity, mental health, and dental health. Furthermore, we examined whether mental health impacted the associations between food insecurity and dental health. MATERIALS AND METHODS: We conducted a cross-sectional study with a convenience sample of 226 older adults (aged 50+), employing survey and dental screening data. Participants were recruited from seven community-based organisations in Washington State, USA. We calculated descriptive statistics and conducted Chi-square tests, t tests, and logistic regression analyses to assess the associations between aspects of dental health (untreated decay, gum disease, and unmet dental needs), mental health (depression and cognitive function), and food insecurity. RESULTS: In our sample, food insecurity was observed in 28.4%, 40.6% had untreated decay, 31.6% gum disease, and 42.5% unmet dental needs. Food insecurity was associated with a higher occurrence of untreated decay and unmet dental needs. Participants experiencing food insecurity had higher odds of gum disease (aOR = 2.3; 95% CI: 1.1, 5.2) and unmet dental needs (aOR = 3.2; 95% CI:1.4, 7.6). Greater gum disease due to food insecurity was observed among individuals with lower levels of cognitive impairment. CONCLUSION: Food insecurity is associated with poorer oral health among older adults and cognitive function may modify this relationship. These findings underscore the importance of addressing both food insecurity and cognitive impairment as integral components of efforts to improve the oral health of older adults.

The Impact of Providing Free HIV Self-testing on Sexual Risk Behaviors Among Men who have Sex with Men in Hunan, China: A Randomized Controlled Trial.

HIV self-testing (HIVST) increases testing frequency among men who have sex with men (MSM). However, its impact on sexual risk behaviors is unclear. In a randomized controlled trial conducted in Hunan Province, China, HIV-negative MSM were randomized to receive one of two interventions for one year: (1) facility-based HIV testing, or (2) facility-based HIV testing augmented with free HIVST. From April to June 2018, 230 MSM were enrolled. They self-reported sexual behaviors every 3 months for 12 months. Among 216 MSM with follow-ups (intervention: 110; control: 106), adjusting for potential confounders in Generalized Estimating Equation models, there were no statistically significant differences in consistent condom use with male partners (regular/casual) or female partners, nor on number of male or female sexual partners. Provision of free HIVST kits does not increase risky sex and should be included in comprehensive HIV prevention packages, particularly for sexual minority men in China.

Psychological pathways to HIV-related posttraumatic stress disorder symptoms among people living with HIV in China: the mediating role of rumination.

The occurrence of HIV-related posttraumatic stress disorder (PTSD) compromises the physical and mental health of people living with HIV (PLWH). This study examined the psychological pathways of HIV-related PTSD symptoms considering the influence of rumination in PLWH of China. A cross-sectional survey was conducted in Changsha, China. The data were collected using the PTSD Checklist-Civilian Version, the Ruminative Response Scale, the Multidimensional Scale of Perceived Social Support, and measures of sociodemographic and HIV-related clinic characteristics. A total of 602 PLWH were surveyed. The average score of HIV-related PTSD symptoms was (34.54 ± 13.58). The mediation model showed that perceived social stigma and physical health exhibited direct associations with PTSD symptoms (ß = 0.093, -0.145, respectively), while the direct relations of family support, friend support and significant others support to PTSD symptoms were not significant. Rumination mediated the effect of perceived social stigma (ß = 0.077), physical health (ß = -0.150), family support (ß = -0.144) and friend support (ß = -0.105) on PTSD symptoms. The study findings underscore the importance of routinely assessing PTSD for PLWH, and developing trauma-focused interventions that alleviate HIV-related PTSD symptoms and reduce rumination while improving social support and physical health and reducing social stigma.

Inferring transmission trees to guide targeting of interventions against visceral leishmaniasis and post-kala-azar dermal leishmaniasis.

Understanding of spatiotemporal transmission of infectious diseases has improved significantly in recent years. Advances in Bayesian inference methods for individual-level geo-located epidemiological data have enabled reconstruction of transmission trees and quantification of disease spread in space and time, while accounting for uncertainty in missing data. However, these methods have rarely been applied to endemic diseases or ones in which asymptomatic infection plays a role, for which additional estimation methods are required. Here, we develop such methods to analyze longitudinal incidence data on visceral leishmaniasis (VL) and its sequela, post-kala-azar dermal leishmaniasis (PKDL), in a highly endemic community in Bangladesh. Incorporating recent data on VL and PKDL infectiousness, we show that while VL cases drive transmission when incidence is high, the contribution of PKDL increases significantly as VL incidence declines (reaching 55% in this setting). Transmission is highly focal: 85% of mean distances from inferred infectors to their secondary VL cases were <300 m, and estimated average times from infector onset to secondary case infection were <4 mo for 88% of VL infectors, but up to 2.9 y for PKDL infectors. Estimated numbers of secondary cases per VL and PKDL case varied from 0 to 6 and were strongly correlated with the infector's duration of symptoms. Counterfactual simulations suggest that prevention of PKDL could have reduced overall VL incidence by up to 25%. These results highlight the need for prompt detection and treatment of PKDL to achieve VL elimination in the Indian subcontinent and provide quantitative estimates to guide spatiotemporally targeted interventions against VL.

Self-efficacy mediates the effect of providing HIV self-testing kits on HIV testing frequency among Chinese men who have sex with men: results from a randomised controlled trial.

BACKGROUND: HIV self-testing (HIVST) could promote HIV tests; however, knowledge about the mechanisms by which providing HIVST kits impacts the uptake of HIV testing is limited. This study aimed to examine how self-efficacy mediates the association between providing HIVST kits and HIV testing frequency. METHODS: In this randomised controlled trial, HIV-negative men who have sex with men (MSM) were recruited in China and randomly assigned 1:1 into intervention and control groups. MSM in the control group could access site-based HIV testing services (SBHT). MSM in the intervention group could access SBHTs plus free HIVST kits. HIV testing self-efficacy, number of SBHTs, number of HIVSTs, and the total number of HIV tests were assessed every 3months for 1year. RESULTS: Data from 216 MSM (intervention group: 110; control group: 106) were included in analysis. Results from Pearson's correlations and point-biserial correlations showed that participants with higher self-efficacy scores underwent a higher number of HIV tests (r =0.241, P <0.001), more HIVSTs (r =0.162, P <0.001), and more SBHTs (r =0.138, P <0.001). Bootstrap tests using PROCESS indicated self-efficacy partially mediated the effect of providing HIVST on the number of HIVSTs (indirect effect: 0.018, 95% bias-corrected confidence interval [BC CI]: 0.003-0.035; direct effect: 0.440, 95% BC CI: 0.366-0.513) and on total HIV tests (indirect effect 0.053 (0.030-0.787); direct effect 0.452 (0.365-0.539)), and completely mediated the effect of providing HIVST on the number of SBHTs (indirect effect 0.035 (0.019-0.056); direct effect 0.012 (-0.059 to 0.083)). CONCLUSIONS: Our findings indicated self-efficacy mediated the effect of HIVST provision on HIV testing frequency, suggesting improving self-efficacy might be an effective way to promote HIV testing among Chinese MSM.

Efferent limb stimulation prior to loop ileostomy closure: a systematic review and meta-analysis.

BACKGROUND: Postoperative ileus (POI) remains a common phenomenon following loop ileostomy closure. Our aim was to determine whether preoperative physiological stimulation (PPS) of the efferent limb reduced POI incidence. METHODS: A PRISMA-compliant meta-analysis searching PubMed, EMBASE and CENTRAL databases was performed. The last search was carried out on 30 January 2023. All randomized studies comparing PPS versus no stimulation were included. The primary endpoint was POI incidence. Secondary endpoints included the time to first passage of flatus/stool, time to resume oral diet, need for nasogastric tube (NGT) placement postoperatively, length of stay (LOS) and other complications. Random effects models were used to calculate pooled effect size estimates. Trial sequential analyses (TSA) were also performed. RESULTS: Three randomized studies capturing 235 patients (116 PPS, 119 no stimulation) were included. On random effects analysis, PPS was associated with a quicker time to resume oral diet (MD - 1.47 days, 95% CI - 2.75 to - 0.19, p = 0.02), shorter LOS (MD - 1.47 days, 95% CI - 2.47 to - 0.46, p = 0.004) (MD - 1.41 days, 95% CI - 2.32 to - 0.50, p = 0.002, I2 = 56%) and fewer other complications (OR 0.42, 95% CI 0.18 to 1.01, p = 0.05). However, there was no difference in POI incidence (OR 0.35, 95% CI 0.10 to 1.21, p = 0.10), the requirement for NGT placement (OR 0.50, 95% CI 0.21 to 1.20, p = 0.12) or time to first passage of flatus/stool (MD - 0.60 days, 95% CI - 1.95 to 0.76, p = 0.39). TSA revealed imprecise estimates for all outcomes (except LOS) and further studies are warranted to meet the required information threshold. CONCLUSIONS: PPS prior to stoma closure may reduce LOS and postoperative complications albeit without a demonstrable beneficial effect on POI. Further high-powered studies are required to confirm or refute these findings.

Unexposed populations and potential COVID-19 hospitalisations and deaths in European countries as per data up to 21 November 2021.

We estimate the potential remaining COVID-19 hospitalisation and death burdens in 19 European countries by estimating the proportion of each country's population that has acquired immunity to severe disease through infection or vaccination. Our results suggest many European countries could still face high burdens of hospitalisations and deaths, particularly those with lower vaccination coverage, less historical transmission and/or older populations. Continued non-pharmaceutical interventions and efforts to achieve high vaccination coverage are required in these countries to limit severe COVID-19 outcomes.

Silver Nanoparticle Synthesis via Photochemical Reduction with Sodium Citrate.

The aim of this paper is to provide a simple and efficient photoassisted approach to synthesize silver nanoparticles, and to elucidate the role of the key factors (synthesis parameters, such as the concentration of TSC, irradiation time, and UV intensity) that play a major role in the photochemical synthesis of silver nanoparticles using TSC, both as a reducing and stabilizing agent. Concomitantly, we aim to provide an easy way to evaluate the particle size based on Mie theory. One of the key advantages of this method is that the synthesis can be "activated" whenever or wherever silver nanoparticles are needed, by premixing the reactants and irradiating the final solution with UV radiation. UV irradiance was determined by using Keitz's theory. This argument has been verified by premixing the reagents and deposited them in an enclosed space (away from sunlight) at 25 °C, then checking them for three days. Nothing happened, unless the sample was directly irradiated by UV light. Further, obtained materials were monitored for 390 days and characterized using scanning electron microscopy, UV-VIS, and transmission electron microscopy.

Frequency of Routine Testing for Coronavirus Disease 2019 (COVID-19) in High-risk Healthcare Environments to Reduce Outbreaks.

Routine asymptomatic testing strategies for COVID-19 have been proposed to prevent outbreaks in high-risk healthcare environments. We used simulation modeling to evaluate the optimal frequency of viral testing. We found that routine testing substantially reduces risk of outbreaks, but may need to be as frequent as twice weekly.

Comparison of infection control strategies to reduce COVID-19 outbreaks in homeless shelters in the United States: a simulation study.

BACKGROUND: COVID-19 outbreaks have occurred in homeless shelters across the US, highlighting an urgent need to identify the most effective infection control strategy to prevent future outbreaks. METHODS: We developed a microsimulation model of SARS-CoV-2 transmission in a homeless shelter and calibrated it to data from cross-sectional polymerase chain reaction (PCR) surveys conducted during COVID-19 outbreaks in five homeless shelters in three US cities from March 28 to April 10, 2020. We estimated the probability of averting a COVID-19 outbreak when an exposed individual is introduced into a representative homeless shelter of 250 residents and 50 staff over 30 days under different infection control strategies, including daily symptom-based screening, twice-weekly PCR testing, and universal mask wearing. RESULTS: The proportion of PCR-positive residents and staff at the shelters with observed outbreaks ranged from 2.6 to 51.6%, which translated to the basic reproduction number (R0) estimates of 2.9-6.2. With moderate community incidence (~ 30 confirmed cases/1,000,000 people/day), the estimated probabilities of averting an outbreak in a low-risk (R0 = 1.5), moderate-risk (R0 = 2.9), and high-risk (R0 = 6.2) shelter were respectively 0.35, 0.13, and 0.04 for daily symptom-based screening; 0.53, 0.20, and 0.09 for twice-weekly PCR testing; 0.62, 0.27, and 0.08 for universal masking; and 0.74, 0.42, and 0.19 for these strategies in combination. The probability of averting an outbreak diminished with higher transmissibility (R0) within the simulated shelter and increasing incidence in the local community. CONCLUSIONS: In high-risk homeless shelter environments and locations with high community incidence of COVID-19, even intensive infection control strategies (incorporating daily symptom screening, frequent PCR testing, and universal mask wearing) are unlikely to prevent outbreaks, suggesting a need for non-congregate housing arrangements for people experiencing homelessness. In lower-risk environments, combined interventions should be employed to reduce outbreak risk.

Towards a Combined Use of Geophysics and Remote Sensing Techniques for the Characterization of a Singular Building: "El Torreón" (the Tower) at Ulaca Oppidum (Solosancho, Ávila, Spain).

This research focuses on the study of the ruins of a large building known as "El Torreón" (the Tower), belonging to the Ulaca oppidum (Solosancho, Province of Ávila, Spain). Different remote sensing and geophysical approaches have been used to fulfil this objective, providing a better understanding of the building's functionality in this town, which belongs to the Late Iron Age (ca. 300-50 BCE). In this sense, the outer limits of the ruins have been identified using photogrammetry and convergent drone flights. An additional drone flight was conducted in the surrounding area to find additional data that could be used for more global interpretations. Magnetometry was used to analyze the underground bedrock structure and ground penetrating radar (GPR) was employed to evaluate the internal layout of the ruins. The combination of these digital methodologies (surface and underground) has provided a new perspective for the improved interpretation of "El Torreón" and its characteristics. Research of this type presents additional guidelines for better understanding of the role of this structure with regards to other buildings in the Ulaca oppidum. The results of these studies will additionally allow archaeologists to better plan future interventions while presenting new data that can be used for the interpretation of this archaeological complex on a larger scale.

The drug adaptaquin blocks ATF4/CHOP-dependent pro-death Trib3 induction and protects in cellular and mouse models of Parkinson's disease.

Identifying disease-causing pathways and drugs that target them in Parkinson's disease (PD) has remained challenging. We uncovered a PD-relevant pathway in which the stress-regulated heterodimeric transcription complex CHOP/ATF4 induces the neuron prodeath protein Trib3 that in turn depletes the neuronal survival protein Parkin. Here we sought to determine whether the drug adaptaquin, which inhibits ATF4-dependent transcription, could suppress Trib3 induction and neuronal death in cellular and animal models of PD. Neuronal PC12 cells and ventral midbrain dopaminergic neurons were assessed in vitro for survival, transcription factor levels and Trib3 or Parkin expression after exposure to 6-hydroxydopamine or 1-methyl-4-phenylpyridinium with or without adaptaquin co-treatment. 6-hydroxydopamine injection into the medial forebrain bundle was used to examine the effects of systemic adaptaquin on signaling, substantia nigra dopaminergic neuron survival and striatal projections as well as motor behavior. In both culture and animal models, adaptaquin suppressed elevation of ATF4 and/or CHOP and induction of Trib3 in response to 1-methyl-4-phenylpyridinium and/or 6-hydroxydopamine. In culture, adaptaquin preserved Parkin levels, provided neuroprotection and preserved morphology. In the mouse model, adaptaquin treatment enhanced survival of dopaminergic neurons and substantially protected their striatal projections. It also significantly enhanced retention of nigrostriatal function. These findings define a novel pharmacological approach involving the drug adaptaquin, a selective modulator of hypoxic adaptation, for suppressing Parkin loss and neurodegeneration in toxin models of PD. As adaptaquin possesses an oxyquinoline backbone with known safety in humans, these findings provide a firm rationale for advancing it towards clinical evaluation in PD.

Impact of providing free HIV self-testing kits on frequency of testing among men who have sex with men and their sexual partners in China: A randomized controlled trial.

BACKGROUND: The HIV epidemic is rapidly growing among men who have sex with men (MSM) in China, yet HIV testing remains suboptimal. We aimed to determine the impact of HIV self-testing (HIVST) interventions on frequency of HIV testing among Chinese MSM and their sexual partners. METHODS AND FINDINGS: This randomized controlled trial was conducted in 4 cities in Hunan Province, China. Sexually active and HIV-negative MSM were recruited from communities and randomly assigned (1:1) to intervention or control arms. Participants in the control arm had access to site-based HIV testing (SBHT); those in the intervention arm were provided with 2 free finger-prick-based HIVST kits at enrollment and could receive 2 to 4 kits delivered through express mail every 3 months for 1 year in addition to SBHT. They were encouraged to distribute HIVST kits to their sexual partners. The primary outcome was the number of HIV tests taken by MSM participants, and the secondary outcome was the number of HIV tests taken by their sexual partners during 12 months of follow-up. The effect size for the primary and secondary outcomes was evaluated as the standardized mean difference (SMD) in testing frequency between intervention and control arms. Between April 14, 2018, and June 30, 2018, 230 MSM were recruited. Mean age was 29 years; 77% attended college; 75% were single. The analysis population who completed at least one follow-up questionnaire included 110 (93%, 110/118) in the intervention and 106 (95%, 106/112) in the control arm. The average frequency of HIV tests per participant in the intervention arm (3.75) was higher than that in the control arm (1.80; SMD 1.26; 95% CI 0.97-1.55; P < 0.001). This difference was mainly due to the difference in HIVST between the 2 arms (intervention 2.18 versus control 0.41; SMD 1.30; 95% CI 1.01-1.59; P < 0.001), whereas the average frequency of SBHT was comparable (1.57 versus 1.40, SMD 0.14; 95% CI -0.13 to 0.40; P = 0.519). The average frequency of HIV tests among sexual partners of each participant was higher in intervention than control arm (2.65 versus 1.31; SMD 0.64; 95% CI 0.36-0.92; P < 0.001), and this difference was also due to the difference in HIVST between the 2 arms (intervention 1.41 versus control 0.36; SMD 0.75; 95% CI 0.47-1.04; P < 0.001) but not SBHT (1.24 versus 0.96; SMD 0.23; 95% CI -0.05 to 0.50; P = 0.055). Zero-inflated Poisson regression analyses showed that the likelihood of taking HIV testing among intervention participants were 2.1 times greater than that of control participants (adjusted rate ratio [RR] 2.10; 95% CI 1.75-2.53, P < 0.001), and their sexual partners were 1.55 times more likely to take HIV tests in the intervention arm compared with the control arm (1.55, 1.23-1.95, P < 0.001). During the study period, 3 participants in the intervention arm and none in the control arm tested HIV positive, and 8 sexual partners of intervention arm participants also tested positive. No other adverse events were reported. Limitations in this study included the data on number of SBHT were solely based on self-report by the participants, but self-reported number of HIVST in the intervention arm was validated; the number of partner HIV testing was indirectly reported by participants because of difficulties in accessing each of their partners. CONCLUSIONS: In this study, we found that providing free HIVST kits significantly increased testing frequency among Chinese MSM and effectively enlarged HIV testing coverage by enhancing partner HIV testing through distribution of kits within their sexual networks. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR1800015584.

Force Field Parameter Development for the Thiolate/Defective Au(111) Interface.

A molecular-level understanding of the interplay between self-assembled monolayers (SAMs) of thiolates and gold surface is of great importance to a wide range of applications in surface science and nanotechnology. Despite theoretical research progress of the past decade, an atomistic model, capable of describing key features of SAMs at reconstructed gold surfaces, is still missing. In this work, periodic ab initio density functional theory (DFT) calculations were utilized to develop a new atomistic force field model for alkanethiolate (AT) SAMs on a reconstructed Au(111) surface. The new force field parameters were carefully trained to reproduce the key features, including vibrational spectra and torsion energy profiles of ethylthiolate (C2S) in the bridge or staple motif model on the Au(111) surface, wherein, the force constants of the bond and angle terms were trained by matching the vibrational spectra, while the torsion parameters of the dihedral angles were trained via fitting the torsion energy profiles from DFT calculations. To validate the developed force field parameters, we performed classical molecular dynamics (MD) simulations for both pristine and reconstructed Au-S interface models with a (2√3 × 3) unit cell, which includes four dodecanethiolate (C10S) molecules on the Au(111) surface. The simulation results showed that the geometrical features of the investigated Au-S interface models and structural properties of the C10S SAMs are in good agreement with the ab initio MD studies. The newly developed atomistic force field model provides new fundamental insights into AT SAMs on the reconstructed Au(111) surface and adds advancement to the existing interface research knowledge.