Evaluation of Molecular Epidemiology, Clinical Characteristics, Antifungal Susceptibility Profiles, and Molecular Mechanisms of Antifungal Resistance of Iranian Candida parapsilosis Species Complex Blood Isolates

Clonal expansion of fluconazole resistant (FLZ-R) Candida parapsilosis isolates is increasingly being identified in many countries, while there is no study exploring the antifungal susceptibility pattern, genetic diversity, and clinical information for Iranian C. parapsilosis blood isolates. Candida parapsilosis species complex blood isolates (n = 98) were recovered from nine hospitals located in three major cities, identified by MALDI-TOF MS, and their genetic relatedness was examined by AFLP fingerprinting. Antifungal susceptibility testing followed CLSI-M27-A3 and ERG11, MRR1 and hotspots 1/2 (HS1/2) of FKS1 were sequenced to assess the azole and echinocandin resistance mechanisms, respectively. Ninety-four C. parapsilosis and four Candida orthopsilosis isolates were identified from 90 patients. Only 43 patients received systemic antifungal drugs with fluconazole as the main antifungal used. The overall mortality rate was 46.6 (42/90) and death mostly occurred for those receiving systemic antifungals (25/43) relative to those not treated (17/47). Although, antifungal-resistance was rare, one isolate was multidrug-resistant (FLZ = 16 μg/ml and micafungin = 8 μg/ml) and the infected patient showed therapeutic failure to FLZ prophylaxis. Mutations causing azole and echinocandin resistance were not found in the genes studied. AFLP revealed five genotypes (G) and G1 was the main one (59/94; 62.7). Clinical outcome was significantly associated with city (P = 0.02, α <0.05) and Mashhad was significantly associated with mortality (P = 0.03, α <0.05). Overall, we found a low level of antifungal resistance for Iranian C. parapsilosis blood isolates, but the noted MDR strain can potentially become the source of future infections and challenge the antifungal therapy in antifungal-naïve patients. AFLP typing results warrants confirmation using other resolutive typing methods. © Copyright © 2020 Arastehfar, Daneshnia, Najafzadeh, Hagen, Mahmoudi, Salehi, Zarrinfar, Namvar, Zareshahrabadi, Khodavaisy, Zomorodian, Pan, Theelen, Kostrzewa, Boekhout and Lass-Flörl

Damp-heat-induced degradation of layers in CIGS solar cells

Investors require a guarantee of a minimum lifetime for PV installations. It is tempting to provide such a guarantee for a longer lifetime simply by specifying test conditions that are more and more severe. In this paper it is argued that, with a more detailed understanding of the basic mechanisms determining cell material behaviour under specific exposure conditions, not only can the inherent lifetime of solar cells and modules be improved, but also the predictive value and effectiveness of lifetime testing. An overview of the literature contributions regarding the influence of damp-heat exposure of the layers in Cu(In,Ga)Se2 (CIGS) solar cells is presented. The material changes, as well as their potential influence on solar cell and module performance, are described. For the molybdenum back contact, it was observed that damp-heat exposure leads to a decrease in conductivity an

Degradation of CIGS solar cells

Thin film CIGS solar cells and individual layers within these solar cells have been tested in order to assess their long term stability. Alongside with the execution of standard tests, in which elevated temperatures and humidity levels are used, the solar cells have also been exposed to a combination of elevated temperature and humidity and illumination, which also allowed in-situ analysis of the changes in the electrical parameters. Additionally, the samples have been tested in the presence of water and various atmospheric species, like CO2, nitrogen and oxygen, in order to assess the impact of these species. Based on these experiments, it was concluded that CIGS solar cells can rapidly lose efficiency due to the migration of sodium, which occurs when exposed to illumination and water vapor. It was also observed that the transparent top electrode, consisting of ZnO:Al degraded rapidly in the presence of a combination of water and CO2, while it is stable in the presence of water combined with e.g. N2 and O2. The thesis also contains an extensive literature study on the stability of CIGS solar cells and a study on the temperature dependency of these solar cells.PhotoVoltaic Devices and MaterialsElectrical Engineering, Mathematics and Computer Scienc

Spherulitic growth of hen egg-white lysozyme crystals

Contains fulltext : 36482.pdf (publisher's version ) (Closed access

The influence of atmospheric species on the degradation of aluminum doped zinc oxide and Cu(In,Ga)Se2 solar cells

Aluminum doped zinc oxide (ZnO:Al) layers were exposed to the atmospheric gases carbondioxide (CO2), oxygen (O2), nitrogen (N2) and air as well as liquid H2O purged with these gases, in order to investigate the chemical degradation behavior of these layers. The samples were analyzed by electrical, compositional and optical measurements before, during and after exposure to these conditions in order to follow the degradation behavior of these layers in time. We have shown that ZnO:Al layers degraded in the presence of a mixture of H2O and CO2. Individually, CO2does not impact the degradation at all during the tested period, while the individual impact of H2O is small. However, when CO2 is also present, the concentration of OH increases greatly in the bulk and even more at the air/ZnO:Al and the ZnO:Al/glass interfaces. Carbon based species are then also present, indicating that Zn5(OH)6(CO3)2 is also formed at the grain boundaries. The degradation of ZnO:Al was accompanied by the occurrence of holes in the ZnO:Al layer near the ZnO:Al/glass interface. The impact of gaseous O2 as well as water purged with N2 and O2 on ZnO:Al degradation is very small. Complete Cu(In,Ga)Se2 solar cells were also exposed to unpurged liquid H2O and H2O purged with CO2, O2, N2 and air. The samples exposed to H2O purged with air and CO2 showed a rapid decrease in efficiency after approximately 180 hours of exposure. This efficiency decrease is mainly driven by a very rapid decrease in current density and an increase in series resistance

The Influence of Heating Time and Temperature on the Properties of CIGSSe Solar Cells

Nonencapsulated CIGSSe solar cells, with a silver grid, were exposed to different temperatures for various periods in order to measure the effect of the heat exposure in CIGSSe modules. The heat treatment time and temperature were varied during the experiments, which were executed at atmospheric conditions. In all the cases, after reaching a temperature of about 300°C, the IV measurement showed a reduction of 2-3% in terms of V O C and J S C. This is confirmed, respectively, by Raman and EQE measurements as well. The efficiency drop was -7%, -29%, and -48%, respectively, for 30 seconds, 300 seconds, and 600 seconds of exposure time. With temperatures larger than 225°C, the series resistance starts to increase exponentially and a secondary barrier becomes visible in the IV curve. This barrier prevents the extraction of electrons and consequently reducing the solar cells efficiency. Lock-in thermography demonstrated the formation of shunts on the mechanical scribes only for 300 and 600 seconds exposure times. The shunt resistance reduction is in the range of 5% for all time periods

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and biphenyls (PCBs) in home-produced eggs

Home produced eggs from 62 addresses in the Netherlands were investigated for the levels of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and biphenyls (PCBs), both dioxin-like (dl) and non-dioxin-like (ndl). Compared to commercial eggs, levels were relatively high with a median of 4.6 pg TEQ g−1 fat for the sum of PCDD/Fs and dl-PCBs, and a highest level of 18.9 pg TEQ g−1 fat. A number of samples showed clearly elevated ndl-PCB levels with a median of 13 ng g−1 fat and a highest level of 80 ng g−1 fat. There were no clear regional differences, even though part of the samples were derived from the rather industrial Rotterdam/Rijnmond area. Based on the congener patterns, former backyard burning of waste seems the most likely source for most eggs, with two exceptions where other sources contributed to the contamination. Similar is true for the ndl-PCBs. The study shows that average levels are about ten-fold higher than commercial eggs and may substantially contribute to the intake of PCDD/Fs and dl-PCBs by consumers. Intervention measures to reduce the intake of these contaminants by laying hens are advised

Influence of deposition pressure and selenisation on damp heat degradation of the Cu(In,Ga)Se2 back contact molybdenum

The impact of the molybdenum (Mo) microstructure and selenisation on degradation caused by 105hour exposure to standard 'damp heat' has been investigated. Degradation effects were already observed without magnification after several hours of exposure. The degradation resulted in large volume expansion due to the formation of a thick non-conductive MoOx layer consisting of various oxides and suboxides on top of the metallic molybdenum. This MoOx layer showed cracks and the appearance of needle-like structures.The degradation effect was the most severe for layers with the highest sputter pressure and thus the most porous microstructure. This can be attributed to higher mobility of the degrading species in the intergranular material (like MoOx) than in metallic Mo. The effect of selenisation was observed in the visual and optical characteristics - the dense selenised molybdenum layer retained the highest reflectance. Likely, the presence of MoSe2 prevented rapid oxidation of the Mo. cop. 2014 Elsevier B.V