309 research outputs found
MOS CCDs for the wide field imager on the XEUS spacecraft
In recent years the XEUS mission concept has evolved and has been the subject of several industrial studies. The mission concept has now matured to the point that it could be proposed for a Phase A study and subsequent flight programme. The key feature of XEUS will be its X-ray optic with collecting area ~30-100x that of XMM. The mission is envisaged at an orbit around the L2 point in space, and is formed from two spacecraft; one for the mirrors, and the other for the focal plane detectors. With a focal length of 50m, the plate scale of the optic is 6.5x that of XMM, which using existing focal plane technology will reduce the effective field of view to a few arc minutes. Cryogenic instrumentation, with detector sizes of a few mm can only be used for narrow field studies of target objects, and a wide field instrument is under consideration using a DEPFET pixel array to image out to a diameter of 5 arcminutes, requiring an array of dimension 70mm. It is envisaged to extend this field of view possibly out to 15 arcminutes through the use of an outer detection ring comprised of MOS CCD
Predictors of linkage to care following community-based HIV counseling and testing in rural Kenya
Despite innovations in HIV counseling and testing (HCT), important gaps remain in understanding linkage to care. We followed a cohort diagnosed with HIV through a community-based HCT campaign that trained persons living with HIV/AIDS (PLHA) as navigators. Individual, interpersonal, and institutional predictors of linkage were assessed using survival analysis of self-reported time to enrollment. Of 483 persons consenting to follow-up, 305 (63.2%) enrolled in HIV care within 3 months. Proportions linking to care were similar across sexes, barring a sub-sample of men aged 18–25 years who were highly unlikely to enroll. Men were more likely to enroll if they had disclosed to their spouse, and women if they had disclosed to family. Women who anticipated violence or relationship breakup were less likely to link to care. Enrolment rates were significantly higher among participants receiving a PLHA visit, suggesting that a navigator approach may improve linkage from community-based HCT campaigns.Vestergaard Frandse
Image informatics strategies for deciphering neuronal network connectivity
Brain function relies on an intricate network of highly dynamic neuronal connections that rewires dramatically under the impulse of various external cues and pathological conditions. Among the neuronal structures that show morphologi- cal plasticity are neurites, synapses, dendritic spines and even nuclei. This structural remodelling is directly connected with functional changes such as intercellular com- munication and the associated calcium-bursting behaviour. In vitro cultured neu- ronal networks are valuable models for studying these morpho-functional changes. Owing to the automation and standardisation of both image acquisition and image analysis, it has become possible to extract statistically relevant readout from such networks. Here, we focus on the current state-of-the-art in image informatics that enables quantitative microscopic interrogation of neuronal networks. We describe the major correlates of neuronal connectivity and present workflows for analysing them. Finally, we provide an outlook on the challenges that remain to be addressed, and discuss how imaging algorithms can be extended beyond in vitro imaging studies
A two-neuron system for adaptive goal-directed decision-making in Lymnaea
During goal-directed decision-making, animals must integrate information from the external environment and their internal state to maximize resource localization while minimizing energy expenditure. How this complex problem is solved by the nervous system remains poorly understood. Here, using a combined behavioural and neurophysiological approach, we demonstrate that the mollusc Lymnaea performs a sophisticated form of decision-making during food-searching behaviour, using a core system consisting of just two neuron types. The first reports the presence of food and the second encodes motivational state acting as a gain controller for adaptive behaviour in the absence of food. Using an in vitro analogue of the decision-making process, we show that the system employs an energy management strategy, switching between a low- and high-use mode depending on the outcome of the decision. Our study reveals a parsimonious mechanism that drives a complex decision-making process via regulation of levels of tonic inhibition and phasic excitation
Empirical Distributions of F-ST from Large-Scale Human Polymorphism Data
Studies of the apportionment of human genetic variation have long established that most human variation is within population groups and that the additional variation between population groups is small but greatest when comparing different continental populations. These studies often used Wright’s FST that apportions the standardized variance in allele frequencies within and between population groups. Because local adaptations increase population differentiation, high-FST may be found at closely linked loci under selection and used to identify genes undergoing directional or heterotic selection. We re-examined these processes using HapMap data. We analyzed 3 million SNPs on 602 samples from eight worldwide populations and a consensus subset of 1 million SNPs found in all populations. We identified four major features of the data: First, a hierarchically FST analysis showed that only a paucity (12%) of the total genetic variation is distributed between continental populations and even a lesser genetic variation (1%) is found between intra-continental populations. Second, the global FST distribution closely follows an exponential distribution. Third, although the overall FST distribution is similarly shaped (inverse J), FST distributions varies markedly by allele frequency when divided into non-overlapping groups by allele frequency range. Because the mean allele frequency is a crude indicator of allele age, these distributions mark the time-dependent change in genetic differentiation. Finally, the change in mean-FST of these groups is linear in allele frequency. These results suggest that investigating the extremes of the FST distribution for each allele frequency group is more efficient for detecting selection. Consequently, we demonstrate that such extreme SNPs are more clustered along the chromosomes than expected from linkage disequilibrium for each allele frequency group. These genomic regions are therefore likely candidates for natural selection
Cultural Competence in End-of-Life Care: Terms, Definitions, and Conceptual Models from the British Literature
Background: Cultural competency is increasingly recommended in policy and practice to improve end-of-life (EoL) care for minority ethnic groups in multicultural societies. It is imperative to critically analyze this approach to understand its underlying concepts. Aim: Our aim was to appraise cultural competency approaches described in the British literature on EoL care and minority ethnic groups.
Design: This is a critical review. Articles on cultural competency were identified from a systematic review of the literature on minority ethnic groups and EoL care in the United Kingdom. Terms, definitions, and conceptual models of cultural competency approaches were identified and situated according to purpose, components, and origin. Content analysis of definitions and models was carried out to identify key components.
Results: One-hundred thirteen articles on minority ethnic groups and EoL care in the United Kingdom were identified. Over half (n=60) contained a term, definition, or model for cultural competency. In all, 17 terms, 17 definitions, and 8 models were identified. The most frequently used term was "culturally sensitive," though "cultural competence" was defined more often. Definitions contained one or more of the components: "cognitive," "implementation," or "outcome." Models were categorized for teaching or use in patient assessment. Approaches were predominantly of American origin.
Conclusions: The variety of terms, definitions, and models underpinning cultural competency approaches demonstrates a lack of conceptual clarity, and potentially complicates implementation. Further research is needed to compare the use of cultural competency approaches in diverse cultures and settings, and to assess the impact of such approaches on patient outcomes
Systematic review of methods used in meta-analyses where a primary outcome is an adverse or unintended event
addresses: Peninsula College of Medicine and Dentistry, St Luke's Campus, University of Exeter, Exeter, UK. [email protected]: PMCID: PMC3528446types: Journal Article; Research Support, Non-U.S. Gov't© 2012 Warren et al.; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Adverse consequences of medical interventions are a source of concern, but clinical trials may lack power to detect elevated rates of such events, while observational studies have inherent limitations. Meta-analysis allows the combination of individual studies, which can increase power and provide stronger evidence relating to adverse events. However, meta-analysis of adverse events has associated methodological challenges. The aim of this study was to systematically identify and review the methodology used in meta-analyses where a primary outcome is an adverse or unintended event, following a therapeutic intervention
Experiences of mpox illness and case management among cis and trans gay, bisexual and other men who have sex with men in England: a qualitative study
Background:
The 2022–2024 global mpox outbreak, occurring primarily in the sexual networks of gay, bisexual and other men who have sex with men (GBMSM), has not been accompanied by a focus on patient perspectives of illness. We explore the experiences of GBMSM diagnosed with mpox in England to understand needs for social and clinical support.
//
Methods:
In-depth interviews (March/July 2023) were conducted with 22 GBMSM diagnosed with mpox in 2022, randomly selected from a national mpox surveillance database, and 4 stakeholders from clinical/community-based organisations. Interviews covered experiences of illness, testing, diagnosis, treatment and contact tracing, and were recorded, transcribed and analysed with a thematic framework.
//
Findings:
Media coverage drawing on homophobic stereotypes around sex between men contributed to feelings of stigma and shame. GBMSM living with HIV appeared to cope better with mpox stigma, drawing on their experiences of being diagnosed with HIV for resilience. Younger GBMSM with less experience of stigmatising illness found mpox diagnosis more traumatic and sometimes required support beyond what was provided. Accessing testing could be complicated when healthcare professionals did not recognise mpox symptoms. Men felt information on course of illness, isolation and vaccination after recovery was often inconsistent and contradictory. GBMSM described that care from sexual health and infectious disease units usually better met their emotional and medical needs. This was frequently linked by men to these services having skills in working with the GBMSM community and managing infection risk sensitively. General hospital services and centralised contact tracing could increase feelings and experiences of stigma as some staff were perceived to lack skills in supporting GBMSM and, sometimes, clinical knowledge. Long-term impacts described by men included mental health challenges, urethral/rectal symptoms and life-changing disability.
//
Interpretation:
In this study stigma was a central feature of mpox illness among GBMSM and could be exacerbated or lessened depending on the clinical and social support provided. Involving communities affected by outbreaks in co-producing, planning and delivering care (including contact-tracing) may help improve support provided.
//
Funding:
TCW, AJR, AS and FMB received support from the National Institute for Health and Care Research (NIHR) under its Programme Grants for Applied Research Programme (Ref: NIHR202038). CS and JS receive support from the National Institute for Health and Care Research Health Protection Research Unit (NIHR HPRU) in Blood Borne and Sexually Transmitted Infections at UCL in partnership with UKHSA; RV receives support from the NIHR HPRU in Emerging and Zoonotic Infections and NIHR HPRU in Gastrointestinal Infections. The views expressed are those of the author(s) and not necessarily those of the NIHR, UK Health Security Agency, World Health Organization or the Department of Health and Social Care
Bone turnover change after randomized switch from tenofovir disoproxil to tenofovir alafenamide fumarate in men with HIV
Objective:
Bone loss in people with HIV (PWH) is poorly understood. Switching tenofovir disoproxil fumarate (TDF) to tenofovir alafenamide (TAF) has yielded bone mineral density (BMD) increases. PETRAM (NCT#:03405012) investigated whether BMD and bone turnover changes correlate.
//
Design:
Open-label, randomized controlled trial.
//
Setting:
Single-site, outpatient, secondary care.
//
Participants:
Nonosteoporotic, virologically suppressed, cis-male PWH taking TDF/emtricitabine (FTC)/rilpivirine (RPV) for more than 24 weeks.
//
Intervention:
Continuing TDF/FTC/RPV versus switching to TAF/FTC/RPV (1 : 1 randomization).
//
Main outcome measures:
:[18F]NaF-PET/CT for bone turnover (standardized uptake values, SUVmean) and dual-energy x-ray absorptiometry for lumbar spine and total hip BMD.
//
Results:
Thirty-two men, median age 51 years, 76% white, median duration TDF/FTC/RPV 49 months, were randomized between 31 August 2018 and 09 March 2020. Sixteen TAF:11 TDF were analyzed. Baseline-final scan range was 23–103 (median 55) weeks. LS-SUVmean decreased for both groups (TAF -7.9% [95% confidence interval -14.4, -1.5], TDF -5.3% [-12.1,1.5], P = 0.57). TH-SUVmean showed minimal changes (TAF +0.3% [-12.2,12.8], TDF +2.9% [-11.1,16.9], P = 0.77). LS-BMD changes were slightly more favorable with TAF but failed to reach significance (TAF +1.7% [0.3,3.1], TDF -0.3 [-1.8,1.2], P = 0.06). Bone turnover markers decreased more with TAF ([CTX -35.3% [-45.7, -24.9], P1NP -17.6% [-26.2, -8.5]) than TDF (-11.6% [-28.8, +5.6] and -6.9% [-19.2, +5.4] respectively); statistical significance was only observed for CTX (P = 0.02, P1NP, P = 0.17).
//
Conclusion:
Contrary to our hypothesis, lumbar spine and total hip regional bone formation (SUVmean) and BMD did not differ postswitch to TAF. However, improved LS-BMD and CTX echo other TAF-switch studies. The lack of difference in SUVmean may be due to inadequate power
Is the Clinical Risk Score for Patients with Colorectal Liver Metastases Still Useable in the Era of Effective Neoadjuvant Chemotherapy?
Background: Several clinical risk scores (CRSs) for the outcome of patients with colorectal liver metastases have been validated, but not in patients undergoing neoadjuvant chemotherapy. Therefore, this study evaluates the predictive value of these CRSs in this specific group. Methods: Between January 2000 and December 2008, all patients undergoing a metastasectomy were analyzed and divided into two groups: 193 patients did not receive neoadjuvant chemotherapy (group A), and 159 patients received neoadjuvant chemotherapy (group B). In group B, the CRSs were calculated before and after administration of neoadjuvant chemotherapy. Results were evaluated by using the CRSs proposed by Nordlinger et al., Fong et al., Nagashima et al., and Konopke et al. Results: In groups A and B, the overall median survival was 43 and 47 months, respectively (P = 0.648). In group A, all CRSs used were of statistically significant predictive value. Before administration of neoadjuvant chemotherapy, only the Nordlinger score was of predictive value. After administration of neoadjuvant chemotherapy, all CRSs were of predictive value again, except for the Konopke score. Conclusions: Traditional CRSs are not a reliable prognostic tool when used in patients before treatment with neoadjuvant chemotherapy. However, CRSs assessed after the administration of neoadjuvant chemotherapy are useful to predict prognosis
- …
