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Aerosol absorption is a key property to assess the radiative impacts of aerosols on climate at both global and regional scales. The aerosol physico-chemical and optical properties remain not sufficiently constrained in climate models, with difficulties to properly represent both the aerosol load and their absorption properties in clear and cloudy scenes, especially for absorbing biomass burning aerosols (BBA). In this study we focus on biomass burning (BB) particle plumes transported above clouds over the southeast Atlantic (SEA) region off the southwest coast of Africa, in order to improve the representation of their physico-chemical and absorption properties. The methodology is based on aerosol regional numerical simulations from the WRF-Chem coupled meteorology–chemistry model combined with a detailed inventory of BB emissions and various sets of innovative aerosol remote sensing observations, both in clear and cloudy skies from the POLDER-3/PARASOL space sensor. Current literature indicates that some organic aerosol compounds (OC), called brown carbon (BrOC), primarily emitted by biomass combustion absorb the ultraviolet-blue radiation more efficiently than pure black carbon (BC). We exploit this specificity by comparing the spectral dependence of the aerosol single scattering albedo (SSA) derived from the POLDER-3 satellite observations in the 443–1020 nm wavelength range with the SSA simulated for different proportions of BC, OC and BrOC at the source level, considering the homogeneous internal mixing state of particles. These numerical simulation experiments are based on two main constraints: maintaining a realistic aerosol optical depth both in clear and above cloudy scenes and a realistic BC/OC mass ratio. Modelling experiments are presented and discussed to link the chemical composition with the absorption properties of BBA and to provide estimates of the relative proportions of black, organic and brown carbon in the African BBA plumes transported over the SEA region for July 2008. The absorbing fraction of organic aerosols in the BBA plumes, i.e. BrOC, is estimated at 2 % to 3 %. The simulated mean SSA are 0.81 (565 nm) and 0.84 (550 nm) in clear and above cloudy scenes respectively, in good agreement with those retrieved by POLDER-3 (0.85±0.05 at 565 nm in clear sky and at 550 nm above clouds) for the studied period.

BackgroundAfter mild COVID-19, some outpatients experience persistent symptoms. However, data are scarce and prospective studies are urgently needed.ObjectivesTo characterize the post-COVID-19 syndrome after mild COVID-19 and identify predictors.ParticipantsOutpatients with symptoms suggestive of COVID-19 with (1) PCR-confirmed COVID-19 (COVID-positive) or (2) SARS-CoV-2 negative PCR (COVID-negative).DesignMonocentric cohort study with prospective phone interview between more than 3 months to 10 months after initial visit to the emergency department and outpatient clinics.Main MeasuresData of the initial visits were extracted from the electronic medical file. Predefined persistent symptoms were assessed through a structured phone interview. Associations between long-term symptoms and PCR results, as well as predictors of persistent symptoms among COVID-positive, were evaluated by multivariate logistic regression adjusted for age, gender, smoking, comorbidities, and timing of the survey.Key ResultsThe study population consisted of 418 COVID-positive and 89 COVID-negative patients, mostly young adults (median age of 41 versus 36 years in COVID-positive and COVID-negative, respectively; p = 0.020) and healthcare workers (67% versus 82%; p = 0.006). Median time between the initial visit and the phone survey was 150 days in COVID-positive and 242 days in COVID-negative patients. Persistent symptoms were reported by 223 (53%) COVID-positive and 33 (37%) COVID-negative patients (p = 0.006) and proportions were stable among the periods of the phone interviews. Overall, 21% COVID-positive and 15% COVID-negative patients (p = 0.182) attended care for this purpose. Four surveyed symptoms were independently associated with COVID-19: fatigue (adjusted odds ratio 2.14, 95% CI 1.04–4.41), smell/taste disorder (26.5, 3.46–202), dyspnea (2.81, 1.10–7.16), and memory impairment (5.71, 1.53–21.3). Among COVID-positive, female gender (1.67, 1.09–2.56) and overweight/obesity (1.67, 1.10–2.56) were predictors of persistent symptoms.ConclusionsMore than half of COVID-positive outpatients report persistent symptoms up to 10 months after a mild disease. Only 4 of 14 symptoms were associated with COVID-19 status. The symptoms and predictors of the post-COVID-19 syndrome need further characterization as this condition places a significant burden on society.

Copernicus Sentinel-3 Surface Topography Mission embarks a two-channel microwave radiometer combined with the altimeter in order to correct the altimeter range for the excess path delay resulting from the presence of water vapour in the troposphere. The in-flight calibration of a single instrument is the critical point to achieve the expected performances. In the context of a constellation, the inter-calibration is even more important. After a presentation of the instrument design, we present the diagnoses used for the calibration of Sentinel-3A, using vicarious calibration over specific areas and double difference methods. The inter-calibration of Sentinel-3B with Sentinel-3A is performed during the tandem phase, using the residual differences of co-located measurements. Finally performances are assessed at crossover points with two parameters, first the wet troposphere correction by comparison with Jason-3; secondly on the Sea Surface Height by difference of variance. Analysis results have shown that Sentinel-3A is well calibrated, consistent with other instruments, and that Sentinel-3B is calibrated within 0.4 K with Sentinel-3A as a reference. Performances and stability fulfill the requirements for both missions.

Although direct-acting antivirals have been used extensively to treat patients with chronic hepatitis C virus (HCV) infection, their clinical effectiveness has not been well reported. We compared the incidence of death, hepatocellular carcinoma, and decompensated cirrhosis between patients treated with direct-acting antivirals and those untreated, in the French ANRS CO22 Hepather cohort. We did a prospective study in adult patients with chronic HCV infection enrolled from 32 expert hepatology centres in France. We excluded patients with chronic hepatitis B, those with a history of decompensated cirrhosis, hepatocellular carcinoma, or liver transplantation, and patients who were treated with interferon-ribavirin with or without first-generation protease inhibitors. Co-primary study outcomes were incidence of all-cause mortality, hepatocellular carcinoma, and decompensated cirrhosis. The association between direct-acting antivirals and these outcomes was quantified using time-dependent Cox proportional hazards models. This study is registered with ClinicalTrials.gov, number NCT01953458. Between Aug 6, 2012, and Dec 31, 2015, 10 166 patients were eligible for the study. 9895 (97%) patients had available follow-up information and were included in analyses. Median follow-up was 33·4 months (IQR 24·0–40·7). Treatment with direct-acting antivirals was initiated during follow-up in 7344 patients, and 2551 patients remained untreated at the final follow-up visit. During follow-up, 218 patients died (129 treated, 89 untreated), 258 reported hepatocellular carcinoma (187 treated, 71 untreated), and 106 had decompensated cirrhosis (74 treated, 32 untreated). Exposure to direct-acting antivirals was associated with increased risk for hepatocellular carcinoma (unadjusted hazard ratio [HR] 2·77, 95% CI 2·07–3·71) and decompensated cirrhosis (3·83, 2·29–6·42). After adjustment for variables (age, sex, body-mass index, geographical origin, infection route, fibrosis score, HCV treatment-naive, HCV genotype, alcohol consumption, diabetes, arterial hypertension, biological variables, and model for end-stage liver disease score in patients with cirrhosis), exposure to direct-acting antivirals was associated with a decrease in all-cause mortality (adjusted HR 0·48, 95% CI 0·33–0·70) and hepatocellular carcinoma (0·66, 0·46–0·93), and was not associated with decompensated cirrhosis (1·14, 0·57–2·27). Treatment with direct-acting antivirals is associated with reduced risk for mortality and hepatocellular carcinoma and should be considered in all patients with chronic HCV infection. INSERM-ANRS (France Recherche Nord & Sud Sida-HIV Hépatites), ANR (Agence Nationale de la Recherche), DGS (Direction Générale de la Santé), MSD, Janssen, Gilead, AbbVie, Bristol-Myers Squibb, and Roche.

Background The efficacy of artemisinin-based combination therapy (ACT) has been established. The objective of the present study was to compare the efficacy and safety in the Central African Republic (CAR) of three commercially available artemisinin-based combinations, artemether + lumefantrine (AL), artesunate + sulphamethoxypyrazine–pyrimethamine (AS-SMP) and artesunate + amodiaquine (AS-AQ), with those of sulphadoxine–pyrimethamine + amodiaquine (SP-AQ), which was the first-line reference treatment in the country from 2004, until it was replaced by ACT in 2006 in accordance with changes in international recommendations based on resistance identified in other regions. Methods Children aged six to 59 months with uncomplicated Plasmodium falciparum malaria were recruited in Bangui, the capital of the CAR. The 251 patients selected were randomly assigned to receive AL ( n = 60), AS-SMP ( n = 58), AS-AQ ( n = 68) or SP-AQ ( n = 65) and were followed up for 28 days. Clinical outcome was classified according to the standard 2003 World Health Organization protocol. Results At day 28, the cure rates in a per-protocol analysis were 92% (48/52) with AL, 93% (50/54) with AS-SMP, 93% (55/59) with AS-AQ and 100% (57/57) with SP-AQ, with no statistically significant difference between the four treatments. Defervescence was significantly faster with AS-AQ than with AL ( p <0.035). Fatigue was reported significantly more frequently by patients receiving AQ than by those treated with AS-SMP or AL ( p = 0.006). All the other adverse events reported were mild, and no significant difference was noted by treatment. Conclusion The three artemisinin-bsed combinations show similar, satisfactory results, comparable to that with SP-AQ. This evaluation is the first conducted in CAR since the official introduction of ACT. It should guide the National Malaria Control Programme in choosing the appropriate ACT for treatment of uncomplicated P. falciparum malaria in the future.

Background The COVID‐19 pandemic has caused a public health emergency in all sectors of society, including universities and other academic institutions in Cameroon. However, little is known concerning the real prevalence of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infections among student communities during the second wave of infection in Cameroon. This study aimed to estimate SARS‐CoV‐2 antibodies seroprevalence among participants in a university community in Cameroon. Methodology A cross‐sectional study was conducted from March to April 2021 in 547 students aged ≥18 years during a mass diagnostic campaign at the School of Health Sciences of the Catholic University of Central Africa (ESS/UCAC). The anti‐SARS‐CoV‐2 antibody screening was done using the Panbio™ COVID‐19 IgG/IgM Rapid Diagnostic Test. Results The overall seroprevalence of SARS‐CoV‐2 antibodies was 27%, of which 89.9% (n = 133) was IgG, 6.7% (n = 10) IgM and 3.4% (n = 5) IgG/IgM positive. The undergraduate students represented 79% (432/547) of the total population and were highly positive with anti‐SARS‐CoV‐2 antibodies 30% (130/432) as compared with postgraduate students 20% (23/115). The total antibody seropositivity was higher in males (34.4%) than females (24.9%). Several factors were associated with an increased risk of SARS‐CoV‐2 seroprevalence including the male gender (OR: 1.61 [95% confidence interval, CI 1.0–2.4]), specialization to medical laboratory (OR: 2.8 [95% CI 1.1–7.1]) and nursing sciences (OR: 2.6 [95% CI 1.1–6.2]). Conclusion Our findings point to extensive and underreported circulation of SARS‐CoV‐2 in a university community during the second wave of infection in Cameroon, which likely resulted in artificially low case counts.

ObjectivesTYK2 is a common genetic risk factor for several autoimmune diseases. This gene encodes a protein kinase involved in interleukin 12 (IL-12) pathway, which is a well-known player in the pathogenesis of systemic sclerosis (SSc). Therefore, we aimed to assess the possible role of this locus in SSc.MethodsThis study comprised a total of 7103 patients with SSc and 12 220 healthy controls of European ancestry from Spain, USA, Germany, the Netherlands, Italy and the UK. Four TYK2 single-nucleotide polymorphisms (V362F (rs2304256), P1104A (rs34536443), I684S (rs12720356) and A928V (rs35018800)) were selected for follow-up based on the results of an Immunochip screening phase of the locus. Association and dependence analyses were performed by the means of logistic regression and conditional logistic regression. Meta-analyses were performed using the inverse variance method.ResultsGenome-wide significance level was reached for TYK2 V362F common variant in our pooled analysis (p=3.08×10−13, OR=0.83), while the association of P1104A, A928V and I684S rare and low-frequency missense variants remained significant with nominal signals (p=2.28×10−3, OR=0.80; p=1.27×10−3, OR=0.59; p=2.63×10−5, OR=0.83, respectively). Interestingly, dependence and allelic combination analyses showed that the strong association observed for V362F with SSc, corresponded to a synthetic association dependent on the effect of the three previously mentioned TYK2 missense variants.ConclusionsWe report for the first time the association of TYK2 with SSc and reinforce the relevance of the IL-12 pathway in SSc pathophysiology.

Genome-wide association studies (GWASs) have identified a number of genetic risk loci associated with systemic sclerosis (SSc) and Crohn’s disease (CD), some of which confer susceptibility to both diseases. In order to identify new risk loci shared between these two immune-mediated disorders, we performed a cross-disease meta-analysis including GWAS data from 5,734 SSc patients, 4,588 CD patients and 14,568 controls of European origin. We identified 4 new loci shared between SSc and CD, IL12RB2 , IRF1 / SLC22A5 , STAT3 and an intergenic locus at 6p21.31. Pleiotropic variants within these loci showed opposite allelic effects in the two analysed diseases and all of them showed a significant effect on gene expression. In addition, an enrichment in the IL-12 family and type I interferon signaling pathways was observed among the set of SSc-CD common genetic risk loci. In conclusion, through the first cross-disease meta-analysis of SSc and CD, we identified genetic variants with pleiotropic effects on two clinically distinct immune-mediated disorders. The fact that all these pleiotropic SNPs have opposite allelic effects in SSc and CD reveals the complexity of the molecular mechanisms by which polymorphisms affect diseases.

Objective To evaluate whether the systemic sclerosis (SSc)-associated IRAK1 non-synonymous single-nucleotide polymorphism rs1059702 is responsible for the Xq28 association with SSc or whether there are other independent signals in the nearby methyl-CpG-binding protein 2 gene (MECP2). Methods We analysed a total of 3065 women with SSc and 2630 unaffected controls from five independent Caucasian cohorts. Four tag single-nucleotide polymorphisms of MECP2 (rs3027935, rs17435, rs5987201 and rs5945175) and the IRAK1 variant rs1059702 were genotyped using TaqMan predesigned assays. A meta-analysis including all cohorts was performed to test the overall effect of these Xq28 polymorphisms on SSc. Results IRAK1 rs1059702 and MECP2 rs17435 were associated specifically with diffuse cutaneous SSc (PFDR=4.12×10−3, OR=1.27, 95% CI 1.09 to 1.47, and PFDR=5.26×10−4, OR=1.30, 95% CI 1.14 to 1.48, respectively), but conditional logistic regression analysis showed that the association of IRAK1 rs1059702 with this subtype was explained by that of MECP2 rs17435. On the other hand, IRAK1 rs1059702 was consistently associated with presence of pulmonary fibrosis (PF), because statistical significance was observed when comparing SSc patients PF+ versus controls (PFDR=0.039, OR=1.30, 95% CI 1.07 to 1.58) and SSc patients PF+ versus SSc patients PF− (p=0.025, OR=1.26, 95% CI 1.03 to 1.55). Conclusions Our data clearly suggest the existence of two independent signals within the Xq28 region, one located in IRAK1 related to PF and another in MECP2 related to diffuse cutaneous SSc, indicating that both genes may have an impact on the clinical outcome of the disease.

Background Yaws is a bacterial skin and bone infectious disease caused by Treponema pallidum pertenue . It is endemic, particularly among pygmies in Central African Republic. To assess the clinical cure rate after treatment with benzathinepenicillin in this population, we conducted a cohort survey of 243 patients in the Lobaye region. Findings and conclusion The rate of healing of lesions after 5 months was 95.9%. This relatively satisfactory level of therapeutic response implies that yaws could be controlled in the Central African Republic. Thus, reinforcement of the management of new cases and of contacts is suggested.