Nucleolar-based Dux repression is essential for embryonic two-cell stage exit.

Upon fertilization, the mammalian embryo must switch from dependence on maternal transcripts to transcribing its own genome, and in mice this involves the transient up-regulation of MERVL transposons and MERVL-driven genes at the two-cell stage. The mechanisms and requirement for MERVL and two-cell (2C) gene up-regulation are poorly understood. Moreover, this MERVL-driven transcriptional program must be rapidly shut off to allow two-cell exit and developmental progression. Here, we report that robust ribosomal RNA (rRNA) synthesis and nucleolar maturation are essential for exit from the 2C state. 2C-like cells and two-cell embryos show similar immature nucleoli with altered structure and reduced rRNA output. We reveal that nucleolar disruption via blocking RNA polymerase I activity or preventing nucleolar phase separation enhances conversion to a 2C-like state in embryonic stem cells (ESCs) by detachment of the MERVL activator Dux from the nucleolar surface. In embryos, nucleolar disruption prevents proper nucleolar maturation and Dux silencing and leads to two- to four-cell arrest. Our findings reveal an intriguing link between rRNA synthesis, nucleolar maturation, and gene repression during early development.

Publisher Correction: Enhanced ferroelectricity in ultrathin films grown directly on silicon.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Enhanced ferroelectricity in ultrathin films grown directly on silicon.

Ultrathin ferroelectric materials could potentially enable low-power perovskite ferroelectric tetragonality logic and nonvolatile memories1,2. As ferroelectric materials are made thinner, however, the ferroelectricity is usually suppressed. Size effects in ferroelectrics have been thoroughly investigated in perovskite oxides-the archetypal ferroelectric system3. Perovskites, however, have so far proved unsuitable for thickness scaling and integration with modern semiconductor processes4. Here we report ferroelectricity in ultrathin doped hafnium oxide (HfO2), a fluorite-structure oxide grown by atomic layer deposition on silicon. We demonstrate the persistence of inversion symmetry breaking and spontaneous, switchable polarization down to a thickness of one nanometre. Our results indicate not only the absence of a ferroelectric critical thickness but also enhanced polar distortions as film thickness is reduced, unlike in perovskite ferroelectrics. This approach to enhancing ferroelectricity in ultrathin layers could provide a route towards polarization-driven memories and ferroelectric-based advanced transistors. This work shifts the search for the fundamental limits of ferroelectricity to simpler transition-metal oxide systems-that is, from perovskite-derived complex oxides to fluorite-structure binary oxides-in which 'reverse' size effects counterintuitively stabilize polar symmetry in the ultrathin regime.

Mid-life household food insecurity and subsequent memory function and rate of decline in rural South Africa, 2004-2022.

INTRODUCTION: We aimed to investigate mid-life food insecurity over time in relation to subsequent memory function and rate of decline in Agincourt, rural South Africa. METHODS: Data from the longitudinal Agincourt Health and Socio-Demographic Surveillance System (Agincourt HDSS) were linked to the population-representative Health and Ageing in Africa: A Longitudinal Study of an INDEPTH Community in South Africa" (HAALSI). Food insecurity (yes vs. no) and food insecurity intensity (never/rarely/sometimes vs. often/very often) in the past month were assessed every 3 years from 2004-2013 in Agincourt HDSS. Cumulative exposure to each food insecurity measure was operationalized as 0, 1, and ≥2 time points. Episodic memory was assessed from 2014/15-2021/22 in HAALSI. Mixed-effects linear regression models were fitted to investigate the associations of each food insecurity measure with memory function and rate of decline over time. RESULTS: A total of 3,186 participants (mean age [SD] in 2004: 53 [12.87]; range: 30-96) were included and 1,173 (36%) participants experienced food insecurity in 2004, while this figure decreased to 490 (15%) in 2007, 489 (15%) in 2010, and 150 (5%) in 2013. Experiencing food insecurity at one time point (vs. never) from 2004-2013 was associated with lower baseline memory function (ß=-0.095; 95% CI: -0.159 to -0.032) in 2014/15 but not rate of memory decline. Higher intensity of food insecurity at ≥ two time points (vs. never) was associated with lower baseline memory function (ß =-0.154, 95% CI: -0.338 to 0.028), although the estimate was imprecise. Other frequencies of food insecurity and food insecurity intensity were not associated with memory function or decline in the fully adjusted models. CONCLUSION: In this setting, mid-life food insecurity may be a risk factor for lower later-life memory function, but not decline.

Magnetic resonance imaging findings in Kenyans and South Africans with active convulsive epilepsy: An observational study.

OBJECTIVE: Focal epilepsy is common in low- and middle-income countries. The frequency and nature of possible underlying structural brain abnormalities have, however, not been fully assessed. METHODS: We evaluated the possible structural causes of epilepsy in 331 people with epilepsy (240 from Kenya and 91 from South Africa) identified from community surveys of active convulsive epilepsy. Magnetic resonance imaging (MRI) scans were acquired on 1.5-Tesla scanners to determine the frequency and nature of any underlying lesions. We estimated the prevalence of these abnormalities using Bayesian priors (from an earlier pilot study) and observed data (from this study). We used a mixed-effect modified Poisson regression approach with the site as a random effect to determine the clinical features associated with neuropathology. RESULTS: MRI abnormalities were found in 140 of 240 (modeled prevalence = 59%, 95% confidence interval [CI]: 53%-64%) of people with epilepsy in Kenya, and in 62 of 91 (modeled prevalence = 65%, 95% CI: 57%-73%) in South Africa, with a pooled modeled prevalence of 61% (95% CI: 56%-66%). Abnormalities were common in those with a history of adverse perinatal events (15/23 [65%, 95% CI: 43%-84%]), exposure to parasitic infections (83/120 [69%, 95% CI: 60%-77%]) and focal electroencephalographic features (97/142 [68%, 95% CI: 60%-76%]), but less frequent in individuals with generalized electroencephalographic features (44/99 [44%, 95% CI: 34%-55%]). Most abnormalities were potentially epileptogenic (167/202, 82%), of which mesial temporal sclerosis (43%) and gliosis (34%) were the most frequent. Abnormalities were associated with co-occurrence of generalized non-convulsive seizures (relative risk [RR] = 1.12, 95% CI: 1.04-1.25), lack of family history of seizures (RR = 0.91, 0.86-0.96), convulsive status epilepticus (RR = 1.14, 1.08-1.21), frequent seizures (RR = 1.12, 1.04-1.20), and reported use of anti-seizure medication (RR = 1.22, 1.18-1.26). SIGNIFICANCE: MRI identified pathologies are common in people with epilepsy in Kenya and South Africa. Mesial temporal sclerosis, the most common abnormality, may be amenable to surgical correction. MRI may have a diagnostic value in rural Africa, but future longitudinal studies should examine the prognostic role.

A Comparison of Treatment of OCD Lesions of the Capitellum With Osteochondral Autograft and Allograft Transplantation.

Osteochondritis dissecans (OCD) of the capitellum occurs relatively infrequently but can be found in young overhead-throwing athletes, most commonly in baseball players and gymnasts. Although non-operative management can effectively treat stable lesions, unstable lesions can lead to debilitating symptoms of the elbow and diminished quality of life without surgical intervention. This article reviews methods of treating OCD of the capitellum categorized by stability, size, and patient characteristics, and seeks to familiarize the reader with the appropriate selection of osteochondral allograft versus autograft in treating large, unstable lesions. We complement this review with 3 case examples, each using either an osteochondral autograft or allograft, and discuss the decision-making methodology used in each case.

Transient increased risk of influenza infection following RSV infection in South Africa: findings from the PHIRST study, South Africa, 2016-2018.

BACKGROUND: Large-scale prevention of respiratory syncytial virus (RSV) infection may have ecological consequences for co-circulating pathogens, including influenza. We assessed if and for how long RSV infection alters the risk for subsequent influenza infection. METHODS: We analysed a prospective longitudinal cohort study conducted in South Africa between 2016 and 2018. For participating households, nasopharyngeal samples were taken twice weekly, irrespective of symptoms, across three respiratory virus seasons, and real-time polymerase chain reaction (PCR) was used to identify infection with RSV and/or influenza. We fitted an individual-level hidden Markov transmission model in order to estimate RSV and influenza infection rates and their interdependence. RESULTS: Of a total of 122,113 samples collected, 1265 (1.0%) were positive for influenza and 1002 (0.8%) positive for RSV, with 15 (0.01%) samples from 12 individuals positive for both influenza and RSV. We observed a 2.25-fold higher incidence of co-infection than expected if assuming infections were unrelated. We estimated that infection with influenza is 2.13 (95% CI 0.97-4.69) times more likely when already infected with, and for a week following, RSV infection, adjusted for age. This equates to 1.4% of influenza infections that may be attributable to RSV in this population. Due to the local seasonality (RSV season precedes the influenza season), we were unable to estimate changes in RSV infection risk following influenza infection. CONCLUSIONS: We find no evidence to suggest that RSV was associated with a subsequent reduced risk of influenza infection. Instead, we observed an increased risk for influenza infection for a short period after infection. However, the impact on population-level transmission dynamics of this individual-level synergistic effect was not measurable in this setting.

The adolescent HIV executive function and drumming (AHEAD) study, a feasibility trial of a group drumming intervention amongst adolescents with HIV.

AHEAD feasibility trial assessed the feasibility and acceptability of an 8-session group drumming programme aiming to improve executive function, depression and anxiety symptoms, and perceived social support in adolescents living with HIV in a rural low-income South African setting. Sixty-eight 12- to 19-year-old adolescents participated. They were individually randomised. The intervention arm (n = 34) received weekly hour-long group drumming sessions. Controls (n = 34) received no intervention. Feasibility and acceptability were assessed using rates of: enrolment; retention; attendance; logistical problems; adolescent-reported acceptability. Secondary measures included: five Oxford Cognitive Screen-Executive Function (OCS-EF) tasks; two Rapid Assessment of Cognitive and Emotional Regulation (RACER) tasks; the Self-Reporting Questionnaire-20 (SRQ-20) measuring depression and anxiety symptoms; the Multidimensional Scale of Perceived Social Support (MSPSS). All feasibility criteria were within green progression limits. Enrolment, retention, and acceptability were high. There was a positive effect on adolescent depressed mood with signal for a working memory effect. There were no significant effects on executive function or socio-emotional scales. Qualitative findings suggested socio-emotional benefits including: group belonging; decreased internalised stigma; improved mood; decreased anxiety. Group drumming is a feasible and acceptable intervention amongst adolescents living with HIV in rural South Africa. A full-scale trial is recommended.

Trends in Physician Payments for Hand Surgery Consultations and Clinic Visits.

PURPOSE: The primary objective of this study was to identify the trends in reimbursement for hand surgeons for new patient visits, outpatient consultations, and inpatient consultations from the years 2010-2018. In addition, we sought to investigate the influence of payer mix and coding level of service on physician reimbursement in these settings. METHODS: The PearlDiver Patients Records Database was used to identify clinical encounters and their respective physician reimbursements for analysis within this study. This database was queried using Current Procedural Terminology codes to identify relevant clinical encounters for inclusion, filtered for the presence of valid demographic information and by physician specialty for the presence of a hand surgeon, and tracked by primary diagnoses. Cost data were then calculated and analyzed regarding the payer type and level of care. RESULTS: In total, 156,863 patients were included in this study. The mean reimbursement for inpatient consultations, outpatient consultations, and new patient encounters increased by 92.75% ($134.85 to $259.93), 17.80% ($161.33 to $190.04), and 26.78% ($102.58 to $130.05), respectively. When normalized to 2018 dollars to adjust for inflation, the percent increases were 67.38%, 2.24%, and 10.09%, respectively. Commercial insurance reimbursed hand surgeons to a greater degree than any other payer type. Mean physician reimbursement differed depending on the level of service billed, with the level of service V reimbursing 4.41 times more than the level of service I visits for new outpatient visits, 3.66 times more for new outpatient consultations, and 3.04 times more for new inpatient consultations. CONCLUSIONS: This study helps to provide physicians, hospitals, and policymakers with objective information regarding the trends in reimbursement to hand surgeons. Although this study indicates increasing reimbursements for consultations and new patient visits to hand surgeons, the margins shrink when adjusted for inflation. LEVEL OF EVIDENCE: Economic Analysis IV.

The worldwide epilepsy treatment gap: A systematic review and recommendations for revised definitions - A report from the ILAE Epidemiology Commission.

OBJECTIVE: In order to more appropriately apply and understand the "epilepsy treatment gap" (ETG) concept in current health systems, revised conceptual and operational definitions of ETG are timely and necessary. This article therefore systematically reviews worldwide studies of the ETG, distinguishing high-, middle-, and low-income regions, and provides recommendations for an updated International League Against Epilepsy (ILAE) definition of ETG. METHODS: A systematic review of the ETG was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. The search was conducted from January 1990 to July 2019, in the online databases of Ovid MEDLINE and Embase. Identified abstracts were reviewed in duplicate and data independently extracted using a standard proforma. Data describing treatment gap information including both diagnostic and therapeutic aspects of access to epilepsy treatment were recorded. Descriptive statistics are presented. RESULTS: The treatment gap reported in the 45 distinctive populations represented 33 countries. Treatment gap definitions varied widely. The reported ETGs ranged broadly from 5.6% in Norway to 100% in parts of Tibet, Togo, and Uganda. The wide range of reported ETGs was multifactorial in origin including true differences in the availability and utilization of health care among study populations, variations in operational definitions of the epilepsy treatment gap, and methodological differences in sampling and identifying representative epilepsy cases in populations. Significance and recommendations For the ETG to be a useful metric to compare levels of unmet epilepsy care across different countries and regions, a standardized definition must be adapted, recognizing some of the limitations of the current definitions. Our proposed definition takes into account the lack of effective health care insurance, the diagnostic gap, the therapeutic gap, quality-of-care, and other unmet health care needs."

The global cost of epilepsy: A systematic review and extrapolation.

OBJECTIVE: Global action for epilepsy requires information on the cost of epilepsy, which is currently unknown for most countries and regions of the world. To address this knowledge gap, the International League Against Epilepsy Commission on Epidemiology formed the Global Cost of Epilepsy Task Force. METHODS: We completed a systematic search of the epilepsy cost-of-illness literature and identified studies that provided a comprehensive set of direct health care and/or indirect costs, followed standard methods of case identification and cost estimation, and used data on a representative population or subpopulation of people with epilepsy. Country-specific costs per person with epilepsy were extracted and adjusted to generate an average cost per person in 2019 US dollars. For countries with no cost data, estimates were imputed based on average costs per person of similar income countries with data. Per person costs for each country were then applied to data on the prevalence of epilepsy from the Global Burden of Disease collaboration adjusted for the treatment gap. RESULTS: One hundred one cost-of-illness studies were included in the direct health care cost database, 74 from North America or Western Europe. Thirteen studies were used in the indirect cost database, eight from North America or Western Europe. The average annual cost per person with epilepsy in 2019 ranged from $204 in low-income countries to $11 432 in high-income countries based on this highly skewed database. The total cost of epilepsy, applying per person costs to the estimated 52.51 million people in the world with epilepsy and adjusting for the treatment gap, was $119.27 billion. SIGNIFICANCE: Based on a summary and extrapolations of this limited database, the global cost of epilepsy is substantial and highly concentrated in countries with well-developed health care systems, higher wages and income, limited treatment gaps, and a relatively small percentage of the epilepsy population.

Nanomechanics of cellulose deformation reveal molecular defects that facilitate natural deconstruction.

Technologies surrounding utilization of cellulosic materials have been integral to human society for millennia. In many materials, controlled introduction of defects provides a means to tailor properties, introduce reactivity, and modulate functionality for various applications. The importance of defects in defining the behavior of cellulose is becoming increasingly recognized. However, fully exploiting defects in cellulose to benefit biobased materials and conversion applications will require an improved understanding of the mechanisms of defect induction and corresponding molecular-level consequences. We have identified a fundamental relationship between the macromolecular structure and mechanical behavior of cellulose nanofibrils whereby molecular defects may be induced when the fibrils are subjected to bending stress exceeding a certain threshold. By nanomanipulation, imaging, and molecular modeling, we demonstrate that cellulose nanofibrils tend to form kink defects in response to bending stress, and that these macromolecular features are often accompanied by breakages in the glucan chains. Direct observation of deformed cellulose fibrils following partial enzymatic digestion reveals that processive cellulases exploit these defects as initiation sites for hydrolysis. Collectively, our findings provide a refined understanding of the interplay between the structure, mechanics, and reactivity of cellulose assemblies.

Successful Nonsurgical Management of a Posteriorly Displaced Medial Clavicular Physeal Fracture in an Adolescent Athlete: A Case Report.

ABSTRACT: Traumatic and sport-related sternoclavicular (SCJ) injuries in adolescent athletes are more commonly physeal fractures rather than true SCJ dislocations. Although rare, posterior displacement of the medial clavicular metaphysis after a physeal fracture necessitates prompt evaluation and treatment. Despite the inherent healing ability of physeal separations, delayed or failed diagnosis has the capacity to cause serious complications or fatality secondary to injury of retrosternal structures. Even with the potential severity, a lack of consensus exists in the literature regarding the most appropriate treatment modality. We report an adolescent football player with a medial clavicular physeal fracture with posterior metaphyseal displacement abutting the left brachiocephalic vein. After nonsurgical management and progression to play, the patient returned to play football. This case not only highlights the diagnostic principles of medial clavicular physeal fractures with posterior metaphyseal displacement but also discusses how these challenging injuries can be managed successfully with conservative treatment.

Incidence of Cognitive Impairment during Aging in Rural South Africa: Evidence from HAALSI, 2014 to 2019.

INTRODUCTION: Despite rapid population aging, there are currently limited data on the incidence of aging-related cognitive impairment in sub-Saharan Africa. We aimed to determine the incidence of cognitive impairment and its distribution across key demographic, social, and health-related factors among older adults in rural South Africa. METHODS: Data were from in-person interviews with 3,856 adults aged ≥40 who were free from cognitive impairment at baseline in the population-representative cohort, "Health and Aging in Africa: a Longitudinal Study of an INDEPTH Community in South Africa" (HAALSI), in Agincourt sub-district, Mpumalanga province, South Africa (2014-19). Cognitive impairment was defined as scoring <1.5 standard deviations below the mean of the baseline distribution of orientation and episodic memory scores. Incidence rates and rate ratios for cognitive impairment were estimated according to key demographic, social, and health-related factors, adjusted for age, sex/gender, and country of birth. RESULTS: The incidence of cognitive impairment was 25.7/1,000 person-years (PY; 95% confidence interval [CI]: 23.0-28.8), weighted for mortality (12%) and attrition (6%) over the 3.5-year mean follow-up (range: 1.5-4.8 years). Incidence increased with age, from 8.9/1,000 PY (95% CI: 5.2-16.8) among those aged 40-44 to 93.5/1,000 PY (95% CI: 75.9-116.3) among those aged 80+, and age-specific risks were similar by sex/gender. Incidence was strongly associated with formal education and literacy, as well as marital status, household assets, employment, and alcohol consumption but not with history of smoking, hypertension, stroke, angina, heart attack, diabetes, or prevalent HIV. CONCLUSIONS: This study presents some of the first incidence rate estimates for aging-related cognitive impairment in rural South Africa. Social disparities in incident cognitive impairment rates were apparent in patterns similar to those observed in many high-income countries.

Community health workers to improve adherence to anti-seizure medication in rural South Africa: Is it cost-effective?

OBJECTIVE: Epilepsy is a common, chronic neurological disorder that disproportionately affects individuals living in low- and middle-income countries (LMICs), where the treatment gap remains high and adherence to medication remains low. Community health workers (CHWs) have been shown to be effective at improving adherence to chronic medications, yet no study assessing the costs of CHWs in epilepsy management has been reported. METHODS: Using a Markov model with age- and sex-varying transition probabilities, we determined whether deploying CHWs to improve epilepsy treatment adherence in rural South Africa would be cost-effective. Data were derived using published studies from rural South Africa. Official statistics and international disability weights provided cost and health state values, respectively, and health gains were measured using quality adjusted life years (QALYs). RESULTS: The intervention was estimated at International Dollars ($) 123 250 per annum per sub-district community and cost $1494 and $1857 per QALY gained for males and females, respectively. Assuming a costlier intervention and lower effectiveness, cost per QALY was still less than South Africa's Gross Domestic Product per capita of $13 215, the cost-effectiveness threshold applied. SIGNIFICANCE: CHWs would be cost-effective and the intervention dominated even when costs and effects of the intervention were unfavorably varied. Health system re-engineering currently underway in South Africa identifies CHWs as vital links in primary health care, thereby ensuring sustainability of the intervention. Further research on understanding local health state utility values and cost-effectiveness thresholds could further inform the current model, and undertaking the proposed intervention would provide better estimates of its efficacy on reducing the epilepsy treatment gap in rural South Africa.

Associations of Father and Adult Male Presence with First Pregnancy and HIV Infection: Longitudinal Evidence from Adolescent Girls and Young Women in Rural South Africa (HPTN 068).

This study, a secondary analysis of the HPTN 068 randomized control trial, aimed to quantify the association of father and male presence with HIV incidence and first pregnancy among 2533 school-going adolescent girls and young women (AGYW) in rural South Africa participating in the trial between March 2011 and April 2017. Participants' ages ranged from 13-20 years at study enrollment and 17-25 at the post-intervention visit. HIV and pregnancy incidence rates were calculated for each level of the exposure variables using Poisson regression, adjusted for age using restricted quadratic spline variables, and, in the case of pregnancy, also adjusted for whether the household received a social grant. Our study found that AGYW whose fathers were deceased and adult males were absent from the household were most at risk for incidence of first pregnancy and HIV (pregnancy: aIRR = 1.30, Wald 95% CI 1.05, 1.61, Wald chi-square p = 0.016; HIV: aIRR = 1.27, Wald 95% CI 0.84, 1.91, Wald chi-square p = 0.263) as compared to AGYW whose biological fathers resided with them. For AGYW whose fathers were deceased, having other adult males present as household members seemed to attenuate the incidence (pregnancy: aIRR = 0.92, Wald 95% CI 0.74, 1.15, Wald chi-square p = 0.462; HIV: aIRR = 0.90, Wald 95% CI 0.58, 1.39, Wald chi-square p = 0.623) such that it was similar, and therefore not statistically significantly different, to AGYW whose fathers were present in the household.

Executive function in HIV-affected children and adolescents: a systematic review and meta-analyses.

This review aimed to determine: whether EF is affected in children and adolescents (2-24-years-old) with perinatal HIV infection, perinatal HIV exposure without infection, and behaviourally acquired HIV. A systematic review (PROSPERO number: CRD42017067813) was conducted using 11 electronic databases (01.01.1981-09.07.2019) and 8 conference websites. Primary quantitative studies with EF scores on cognitive tasks and/or behavioural report measures were included. Meta-analyses were performed by EF subtype and subpopulations compared. 1789 records were found. Sixty-one studies were included in the narrative synthesis; 32 (N = 7884 participants) were included in meta-analyses. There was a distinct pattern of reduced EF in those with perinatal HIV infection on antiretroviral therapy compared to controls: pooled effect sizes were largest for verbal and visuospatial working memory, with smaller effects on planning, inhibitory control and set-shifting. Data were limited for other HIV-affected subpopulations. Perinatal HIV infection is associated with reduced EF with varying effect sizes for the different EF subtypes.

Throwing the bones to diagnose HIV: Views of rural South African traditional healers on undertaking HIV counselling and testing.

In 2018, nearly 800,000 HIV positive individuals in South Africa were unaware of their status. Traditional healers see patients who avoid health clinics, including those who refuse HIV testing. This manuscript details the results of a qualitative study to understand traditional healer perspectives on performing healer-initiated HIV counseling and testing HIV in rural South Africa. We conducted 30 structured in-depth interviews between April and June 2019 to elicit traditional healer attitudes towards partnering with local health services to perform HIV counseling and testing with their patients. Healers reported that while some patients are open about their HIV status, others lie about it due to stigma. This creates challenges with concurrent treatment, which healers believe leads to allopathic and/or traditional medication treatment failure. Most healers expressed both an interest and a willingness to perform HIV counseling and testing. Healers felt that by performing testing in the community, it would overcome issues related to HIV stigma, as well as a lack of confidentiality and trust with health care workers at the clinic. Trained traditional healers may be able to bridge the testing gap between "non-testers" and the allopathic health system, essentially "opening" thousands of new testing locations with little financial investment.

The relationship between executive function, risky behaviour and HIV in young women from the HPTN 068 study in rural South Africa.

Executive function (EF) may predict sexual risk-taking and HIV risk in young women in rural South Africa. We tested associations between EF and seven risky behavioural outcomes: binge drinking, illicit substance use, unprotected vaginal sex, concurrent sexual relationships, transactional sex, herpes simplex virus type 2 (HSV-2) infection, and HIV infection. We compared EF in young women with HIV to matched controls. 1080 young women underwent cognitive assessments. Better verbal short-term memory was associated with a lower risk of HSV-2 (OR 0.77; 95% CI 0.69, 0.86; p < 0.001). Uncorrected trends (p < 0.05) were better verbal working memory being associated with a lower risk of concurrency, better planning with a lower risk of illicit drug use, and better affective inhibition with a lower risk of transactional sex. 78 participants with sexually acquired HIV were matched with 153 HIV-negative controls and had poorer verbal working memory than controls (Hedge's g = -0.38; 95% CI -0.66, -0.10; p = 0.0076), but this was non-significant after adjustment. EF's contribution to young women's risky behaviour in this context does not hold when stringent statistical corrections are applied, with only verbal short term memory reaching statistical significance as predictor. Replication in other samples is recommended.

Nanomechanical sampling of material for nanoscale mass spectrometry chemical analysis.

The ability to spatially resolve the chemical distribution of compounds on a surface is important in many applications ranging from biological to material science. To this extent, we have recently introduced a hybrid atomic force microscopy (AFM)-mass spectrometry (MS) system for direct thermal desorption and pyrolysis of material with nanoscale chemical resolution. However, spatially resolved direct surface heating using local thermal desorption becomes challenging on material surfaces with low melting points, because the material will undergo a melting phase transition due to heat dissipation prior to onset of thermal desorption. Therefore, we developed an approach using mechanical sampling and collection of surface materials on an AFM cantilever probe tip for real-time analysis directly from the AFM tip. This approach allows for material to be concentrated directly onto the probe for subsequent MS analysis. We evaluate the performance metrics of the technique and demonstrate localized MS sampling from a candelilla wax matrix containing UV stabilizers avobenzone and oxinoxate from areas down to 250 nm × 250 nm. Overall, this approach removes heat dissipation into the bulk material allowing for a faster desorption and concentration of the gas phase analyte from a single heating pulse enabling higher signal levels from a given amount of material in a single sampling spot.Graphical abstract.