Electron mean free path from angle-dependent photoelectron spectroscopy of aerosol particles

We propose angle-resolved photoelectron spectroscopy of aerosol particles as an alternative way to determine the electron mean free path of low energy electrons in solid and liquid materials. The mean free path is obtained from fits of simulated photoemission images to experimental ones over a broad range of different aerosol particle sizes. The principal advantage of the aerosol approach is twofold. Firstly, aerosol photoemission studies can be performed for many different materials, including liquids. Secondly, the size-dependent anisotropy of the photoelectrons can be exploited in addition to size-dependent changes in their kinetic energy. These finite size effects depend in different ways on the mean free path and thus provide more information on the mean free path than corresponding liquid jet, thin film, or bulk data. The present contribution is a proof of principle employing a simple model for the photoemission of electrons and preliminary experimental data for potassium chloride aerosol particles

Adaptive landscape genetics and malaria across divergent island bird populations

Environmental conditions play a major role in shaping the spatial distributions of pathogens, which in turn can drive local adaptation and divergence in host genetic diversity. Haemosporidians, such as Plasmodium (malaria), are a strong selective force, impacting survival and fitness of hosts, with geographic distributions largely determined by habitat suitability for their insect vectors. Here, we have tested whether patterns of fine‐scale local adaptation to malaria are replicated across discrete, ecologically differing island populations of Berthelot's pipits Anthus berthelotii . We sequenced TLR4, an innate immunity gene that is potentially under positive selection in Berthelot's pipits, and two SNPs previously identified as being associated with malaria infection in a genome‐wide association study (GWAS) in Berthelot's pipits in the Canary Islands. We determined the environmental predictors of malaria infection, using these to estimate variation in malaria risk on Porto Santo, and found some congruence with previously identified environmental risk factors on Tenerife. We also found a negative association between malaria infection and a TLR4 variant in Tenerife. In contrast, one of the GWAS SNPs showed an association with malaria risk in Porto Santo, but in the opposite direction to that found in the Canary Islands GWAS. Together, these findings suggest that disease‐driven local adaptation may be an important factor in shaping variation among island populations

Health system readiness and the implementation of rectal artesunate for severe malaria in sub-Saharan Africa: an analysis of real-world costs and constraints

BACKGROUND: Rectal artesunate, an efficacious pre-referral treatment for severe malaria in children, was deployed at scale in Uganda, Nigeria, and DR Congo. In addition to distributing rectal artesunate, implementation required additional investments in crucial but neglected components in the care for severe malaria. We examined the real-world costs and constraints to rectal artesunate implementation. METHODS: We collected primary data on baseline health system constraints and subsequent rectal artesunate implementation expenditures. We calculated the equivalent annual cost of rectal artesunate implementation per child younger than 5 years at risk of severe malaria, from a health system perspective, separating neglected routine health system components from incremental costs of rectal artesunate introduction. FINDINGS: The largest baseline constraints were irregular health worker supervisions, inadequate referral facility worker training, and inadequate malaria commodity supplies. Health worker training and behaviour change campaigns were the largest startup costs, while supervision and supply chain management accounted for most annual routine costs. The equivalent annual costs of preparing the health system for managing severe malaria with rectal artesunate were US$2.63,$2.20, and $4.19 per child at risk and$322, $219, and$464 per child treated in Uganda, Nigeria, and DR Congo, respectively. Strengthening the neglected, routine health system components accounted for the majority of these costs at 71.5%, 65.4%, and 76.4% of per-child costs, respectively. Incremental rectal artesunate costs accounted for the minority remainder. INTERPRETATION: Although rectal artesunate has been touted as a cost-effective pre-referral treatment for severe malaria in children, its real-world potential is limited by weak and under-financed health system components. Scaling up rectal artesunate or other interventions relying on community health-care providers only makes sense alongside additional, essential health system investments sustained over the long term. FUNDING: Unitaid. TRANSLATION: For the French translation of the abstract see Supplementary Materials section

Effect of Antibiotic Prescription Audit and Feedback on Antibiotic Prescribing in Primary Care: A Randomized Clinical Trial.

IMPORTANCE: Antibiotics are commonly prescribed in primary care, increasing the risk of antimicrobial resistance in the population. OBJECTIVE: To investigate the effect of quarterly audit and feedback on antibiotic prescribing among primary care physicians in Switzerland with medium to high antibiotic prescription rates. DESIGN, SETTING, AND PARTICIPANTS: This pragmatic randomized clinical trial was conducted from January 1, 2018, to December 31, 2019, among 3426 registered primary care physicians and pediatricians in single or small practices in Switzerland who were among the top 75% prescribers of antibiotics. Intention-to-treat analysis was performed using analysis of covariance models and conducted from September 1, 2021, to January 31, 2022. INTERVENTIONS: Primary care physicians were randomized in a 1:1 fashion to undergo quarterly antibiotic prescribing audit and feedback with peer benchmarking vs no intervention for 2 years, with 2017 used as the baseline year. Anonymized patient-level claims data from 3 health insurers serving roughly 50% of insurees in Switzerland were used for audit and feedback. The intervention group also received evidence-based guidelines for respiratory tract and urinary tract infection management and community antibiotic resistance information. Physicians in the intervention group were blinded regarding the nature of the trial, and physicians in the control group were not informed of the trial. MAIN OUTCOMES AND MEASURES: The claims data used for audit and feedback were analyzed to assess outcomes. Primary outcome was the antibiotic prescribing rate per 100 consultations during the second year of the intervention. Secondary end points included overall antibiotic use in the first year and over 2 years, use of quinolones and oral cephalosporins, all-cause hospitalizations, and antibiotic use in 3 age groups. RESULTS: A total of 3426 physicians were randomized to the intervention (n = 1713) and control groups (n = 1713) serving 629 825 and 622 344 patients, respectively, with a total of 4 790 525 consultations in the baseline year of 2017. In the entire cohort, a 4.2% (95% CI, 3.9%-4.6%) relative increase in the antibiotic prescribing rate was noted during the second year of the intervention compared with 2017. In the intervention group, the median annual antibiotic prescribing rate per 100 consultations was 8.2 (IQR, 6.1-11.4) in the second year of the intervention and was 8.4 (IQR, 6.0-11.8) in the control group. Relative to the overall increase, a -0.1% (95% CI, -1.2% to 1.0%) lower antibiotic prescribing rate per 100 consultations was found in the intervention group compared with the control group. No relevant reductions in specific antibiotic prescribing rates were noted between groups except for quinolones in the second year of the intervention (-0.9% [95% CI, -1.5% to -0.4%]). CONCLUSIONS AND RELEVANCE: This randomized clinical trial found that quarterly personalized antibiotic prescribing audit and feedback with peer benchmarking did not reduce antibiotic prescribing among primary care physicians in Switzerland with medium to high antibiotic prescription rates. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03379194

Effectiveness and cost-effectiveness of community-based TB screening algorithms using computer-aided detection (CAD) technology alone compared with CAD combined with point-of-care C reactive protein testing in Lesotho and South Africa: protocol for a paired screen-positive trial

Introduction: Tuberculosis (TB) remains a significant public health challenge in many African communities, where underreporting and underdiagnosis are prevalent due to barriers in accessing care and inadequate diagnostic tools. This is particularly concerning in hard-to-reach areas with a high burden of TB/HIV co-infection, where missed or delayed diagnoses exacerbate disease transmission, increase mortality and lead to severe economic and health consequences. To address these challenges, it is crucial to evaluate innovative, cost-effective, community-based screening strategies that can improve early detection and linkage to care. Methods and analysis: We conduct a prospective, community-based, diagnostic, pragmatic trial in communities of the Butha Buthe District in Lesotho and the Greater Edendale area of Msunduzi Municipality, KwaZulu-Natal in South Africa to compare two strategies for population-based TB screening: computer-aided detection (CAD) technology alone (CAD4TBv7 approach) versus CAD combined with point-of-care C reactive protein (CRP) testing (CAD4TBv7-CRP approach). Following a chest X-ray, CAD produces an abnormality score, which indicates the likelihood of TB. Score thresholds informing the screening logic for both approaches were determined based on the WHO's target product profile for a TB screening test. CAD scores above a threshold prespecified for the CAD4TBv7 approach indicate confirmatory testing for TB (Xpert MTB/RIF Ultra). For the CAD4TBv7-CRP approach, a CAD score within a predefined window requires the conduct of the second screening test, CRP, while a score above the respective upper threshold is followed by Xpert MTB/RIF Ultra. A CRP result above the selected cut-off also requires a confirmatory TB test. Participants with CAD scores below the (lower) threshold and those with CRP levels below the cut-off are considered screen-negative. The trial aims to compare the yield of detected TB cases and cost-effectiveness between two screening approaches by applying a paired screen-positive design. 20 000 adult participants will be enrolled and will receive a posterior anterior digital chest X-ray which is analysed by CAD software. Ethics and dissemination: The protocol was approved by National Health Research Ethics Committee in Lesotho (NH-REC, ID52-2022), the Human Sciences Research Council Research Ethics Committee (HSRC REC, REC 2/23/09/20) and the Provincial Health Research Committee of the Department of Health of KwaZulu-Natal (KZ_202209_022) in South Africa and from the Swiss Ethics Committee Northwest and Central Switzerland (EKNZ, AO_2022-00044). This manuscript is based on protocol V.4.0, 19 January 2024. Trial findings will be disseminated through peer-reviewed publications, conference presentations and through communication offices of the consortium partners and the project's website (https://tbtriage.com/). Trial registration: ClinicalTrials.gov (NCT05526885), South African National Clinical Trials Register (SANCTR; DOH-27-092022-8096)

Mapping the drivers of parasitic weed abundance at a national scale : a new approach applied to Striga asiatica in the mid‐west of Madagascar

The parasitic weed genus Striga causes huge losses to crop production in sub‐Saharan Africa, estimated to be in excess of $7 billion per year. There is a paucity of reliable distribution data for Striga ; however, such data are urgently needed to understand current drivers, better target control efforts, as well as to predict future risks. To address this, we developed a methodology to enable rapid, large‐scale monitoring of Striga populations. We used this approach to uncover the factors that currently drive the abundance and distribution of Striga asiatica in Madagascar. Two long‐distance transects were established across the middle‐west region of Madagascar in which S. asiatica abundance in fields adjacent to the road was estimated. Management, crop structure and soil data were also collected. Analysis of the data suggests that crop variety, companion crop and previous crop were correlated with Striga density. A positive relationship between within‐field Striga density and the density of the nearest neighbouring fields indicates that spatial configuration and connectivity of suitable habitats is also important in determining Striga spread. Our results demonstrate that we are able to capture distribution and management data for Striga density at a landscape scale and use this to understand the ecological and agronomic drivers of abundance. The importance of crop varieties and cropping patterns is significant, as these are key socio‐economic elements of Malagasy cropping practices. Therefore, they have the potential to be promoted as readily available control options, rather than novel technologies requiring introduction

EMSL Science Theme Advisory Panel Workshop - Atmospheric Aerosol Chemistry, Climate Change, and Air Quality

This report contains the workshop scope and recommendations from the workshop attendees in identifying scientific gaps in new particle formation, growth and properties of particles and reactions in and on particles as well as the laboratory-focused capabilities, field-deployable capabilities and modeling/theory tools along with linking of models to fundamental data

Infrared spectroscopy of particulate matter: between molecular clusters and bulk

The present contribution focuses on the vibrational dynamics of large molecular aggregates with sizes ranging from the subnanometre to the micrometre region. These aggregates or particles bridge the gap between molecular clusters and bulk matter. Depending on the kind of intermolecular interactions, the vibrational dynamics of the particles can be strongly influenced by intrinsic particle properties such as size, shape, or surface area. Such phenomena are discussed for several examples. In contrast, for some substances the vibrational spectra are mainly governed by local effects, i.e. by the interaction of neighboring molecules. The comparison of the experimental results with different model calculations leads to a deeper insight into the microscopic origin of the characteristic patterns observed. The vibrational dynamics are studied by Fourier transform infrared spectroscopy. In addition, the particle properties are characterized by microscopy and measurements of the size distribution. Four different particle generation methods are discussed. It is shown that the methods of generation can even influence the chemical composition of the particles