Copper indium gallium sulfur (CIGS) solar cells show good efficiency; however, the buffer/absorber and absorber/back contact interfaces are the most critical factors affecting that efficiency. We ...have investigated CIGS-based solar cells with two different buffer layers, ZnO
1−
x
S
x
and SnS
2
, a non-toxic alternative to CdS using a solar cell capacitance simulator. First, we propose a cell structure with a ZnO
1−
x
S
x
/CIGS interface for different sulfur content in ZnO
1−
x
S
x
. The band gap of ZnO
1−
x
S
x
and the conduction band offset (∆
E
c
) at the ZnO
1−
x
S
x
/CIGS interface can be tuned by the sulfur content, enabling high efficiency. We found that the ZnO
1−
x
S
x
buffer layer with a sulfur composition S/(O + S) ratio of 0.85 leads to enhanced performance of CIGS solar cells up to 23.94%. Above 0.85, the performance of the solar cells is affected, depending on its thickness and the carrier concentration of both absorber and buffer layers. The CIGS solar cell performance was evaluated using SnS
2
as a buffer layer. The results show that the efficiency of CIGS-based solar cells with Zn(O
0.30
S
0.79
) and with SnS
2
is slightly different, at 23.54% and 23.44%, respectively. In addition, there is a difference in the open-circuit voltage (
V
oc
) and short-circuit current density (
J
sc
) due to the reduction in the interface recombination and band structure at the buffer/CIGS interface.
Photovoltaic perovskites are very attractive candidates as absorber layers because of their very interesting properties. In the present work, we have two parts: first, we prepared powders of the ...perovskites MAPbBr
3
, MAPbI
3
, and MAPbCl
3
, with the aim of maximizing their purity, and then we deposited thin films using these powders previously prepared by the one-step spin-coating method. The anti-solvent used was under the same ambient deposition conditions. We concluded with a series of characterizations such as X-ray diffraction, scanning electron microscopy, and UV–visible absorption to better appreciate the quality of the films produced. The crystalline structures of the films, their surface morphology, and their optical properties from the characterizations show that we have succeeded in producing film samples suitable for photovoltaics.
The emergence of rifampicin-resistant tuberculosis (RR-TB) is a major issue for TB control programs due to high risk of treatment failure and death. The objective of this study was to describe ...survival and to determine predictors of death in RR-TB patients treated with the short regimen (9-11 months) in the Conakry TB treatment centers. Sociodemographic, clinical, and survival data were collected prospectively between 2016 and 2021 on RR-TB patients in the Department of Pneumo-Phtisiology, the Carrière and the Tombolia TB centers. The Kaplan-Meier method was used to estimate the cumulative incidence of death of patients. The Cox regression model was used to identify the predictors independently associated with death. Of 869 patients, 164 (18.9%) patients died during treatment, 126 of them within 120 days of treatment initiation. The factors associated with death during treatment were as follows: patients treated in the Carrière TB center (adjusted hazard ratio aHR = 1.65; 95% CI: 1.06-2.59) and in the Department of Pneumo-Phtisiology (aHR = 3.26; 95% CI: 2.10-5.07), patients ≥ 55 years old (aHR = 4.80; 95% CI: 2.81-8.19), patients with no history of first-line TB treatment (aHR = 1.51; 95% CI: 1.05-2.16), and patients living with HIV (aHR = 2.81; 95% CI: 1.94-4.07). The results of this study can help the national TB control program to reconsider its therapeutic strategy to improve patient care in case of RR-TB. Large prospective clinical studies should be conducted to provide evidence of the impact of such factors like previous history of TB treatment and HIV infection on survival of RR-TB patients.
To clarify the role of bats in the ecology of Ebola viruses, we assessed the prevalence of Ebola virus antibodies in a large-scale sample of bats collected during 2015-2017 from countries in Africa ...that have had previous Ebola outbreaks (Guinea, the Democratic Republic of the Congo) or are at high risk for outbreaks (Cameroon). We analyzed 4,022 blood samples of bats from >12 frugivorous and 27 insectivorous species; 2-37 (0.05%-0.92%) bats were seropositive for Zaire and 0-30 (0%-0.75%) bats for Sudan Ebola viruses. We observed Ebola virus antibodies in 1 insectivorous bat genus and 6 frugivorous bat species. Certain bat species widespread across Africa had serologic evidence of Zaire and Sudan Ebola viruses. No viral RNA was detected in the subset of samples tested (n = 665). Ongoing surveillance of bats and other potential animal reservoirs are required to predict and prepare for future outbreaks.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This study aimed to demonstrate that the genomic material of SARS-CoV-2 can be isolated from strips of COVID-19 rapid diagnostic test cassettes. It was a prospective cross-sectional study involving ...patients admitted to treatment centers and sampling sites in the city of Conakry, Guinea. A total of 121 patients were double sampled, and 9 more patients were tested only for RDT. PCR was conducted according to the protocol of the RunMei kit. Sequencing was performed by using the illumina COVIDSeq protocol. Nine COVID-19 RDTs without nasopharyngeal swabs were in addition tested. Among the 130 COVID-19 RDTs, forty-seven were macroscopically positive, whereas seventy-two were positive according to PCR using RDT strip, while among the 121 VTM swabs, sixty-four were positive. Among eighty-three negative COVID-19 RDTs, twenty-seven were positive by PCR using RDT strip with a geometric mean Ct value of 32.49 cycles. Compared to those of PCR using VTM, the sensitivity and specificity of PCR using RDT strip were estimated to be 100% and 85.96%, respectively, with 93.39% test accuracy. Among the fifteen COVID-19 RDT extracts eligible for sequencing, eleven had sequences identical to those obtained via the standard method, with coverage between 75 and 99.6%. These results show that COVID-19 RDTs can be used as biological material for the genomic surveillance of SARS-CoV-2.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The composite coverage index (CCI) is the weighted average coverage of eight preventive and curative interventions received along the maternal and childcare continuum. This study aimed to analyse ...maternal and child health indicators using CCI.
We performed a secondary analysis of demographic and health surveys (DHS) focused on women aged 15 to 49 and their children aged 1 to 4. This study took place in Guinea. The CCI (meeting the need for planning, childbirth assisted by qualified healthcare workers, antenatal care assisted by qualified healthcare workers, vaccination against diphtheria, pertussis, tetanus, measles and Bacillus Calmette-Guérin, taking oral rehydration salts during diarrhoea and seeking care for pneumonia) is optimal if the weighted proportion of interventions is > 50%; otherwise, it is partial. We identified the factors associated with CCI using the descriptive association tests, the spatial autocorrelation statistic and multivariate logistic regression.
The analyses involved two DHS surveys, with 3034 included in 2012 and 4212 in 2018. The optimal coverage of the CCI has increased from 43% in 2012 to 61% in 2018. In multivariate analysis, in 2012: the poor had a lower probability of having an optimal CCI than the richest; OR = 0.11 95% CI; 0.07, 0.18. Those who had done four antenatal care visits (ANC) were 2.78 times more likely to have an optimal CCI than those with less OR = 2.78 95% CI;2.24, 3.45. In 2018: the poor had a lower probability of having an optimal CCI than the richest OR = 0.27 95% CI; 0.19, 0.38. Women who planned their pregnancies were 28% more likely to have an optimal CCI than those who had not planned OR = 1.28 95% CI;1.05, 1.56. Finally, women with more than 4 ANC were 2.43 times more likely to have an optimal CCI than those with the least OR = 2.43 95% CI; 2.03, 2.90. The spatial analysis reveals significant disparities with an aggregation of high partial CCI in Labé between 2012 and 2018.
This study showed an increase in CCI between 2012 and 2018. Policies should improve access to care and information for poor women. Besides, strengthening ANC visits and reducing regional inequalities increases optimal CCI.
Abstract
Neglected tropical diseases (NTDs) predominantly affect vulnerable and marginalized populations in tropical and subtropical areas and globally affect more than one billion people. In Guinea, ...the burden of NTDs is estimated to be >7.5 disability-adjusted life years per million inhabitants. Currently the Guinea NTDs master plan (2017–2020) has identified eight diseases as public health problems: onchocerciasis, lymphatic filariasis, trachoma, schistosomiasis and soil-transmitted helminthiasis, leprosy, human African trypanosomiasis and Buruli ulcer. In this review we discuss the past and the current case burden of the priority NTDs in Guinea, highlight the major milestones and discuss current and future areas of focus for achieving the 2030 target outlined by the World Health Organization.
Previous studies show that arthralgia is the most common symptom experienced by Ebola virus disease (EVD) survivors. Nevertheless, specific analyses of rheumatological sequelea are still lacking.
The ...Postebogui study is a prospective, multicentre cohort aiming to evaluate the long-term outcomes of EVD survivors infected during the 2014-15 outbreak in Guinea. Of the 216 participants enrolled in the study in October 2015, 44 patients with arthralgia/myalgia underwent a physical examination by a rheumatologist (the Eborheum cohort). Data were collected using a standardized questionnaire.
In the Eborheum cohort, 61% of patients were female, the median age was 31.1 years, and the median time from Ebola Treatment Centre discharge was 8.8 months. Pain manifestation started after Ebola infection in all but one patient. Patients had mainly both mechanical and inflammatory pain (45%) and low back pain (77%). All patients reported pain in at least one peripheral joint. Pain in large joints was more frequently reported than in small joints (73 vs 41%). Oligo- and polyarticular presentations were similar, with symmetrical pain distribution. Furthermore, 36 patients had at least one painful 18-tender point count, most of whom reported extensive pain (n = 19) and symmetrical distribution (91%). Diagnoses were mainly non-specific musculoskeletal disorders (59%) and mechanical back pain (52%). No polyarthritis was observed. We found a higher percentage of depressed patients compared with the remaining Postebogui group (42 vs 11%; P < 0.001).
Results from the study come from the first complete rheumatological examination of a cohort of EVD survivors, nearly 9 months after Ebola Treatment Centre discharge. Importantly, we found that patients with arthralgia/myalgia included in the Eborheum cohort were more likely to experience depression than survivors not reporting these symptoms, highlighting the impact of pain symptoms among survivors.
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