453 research outputs found

    Influence of copper on the electronic properties of amorphous chalcogenides

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    We have studied the influence of alloying copper with amorphous arsenic sulfide on the electronic properties of this material. In our computer-generated models, copper is found in two-fold near-linear and four-fold square-planar configurations, which apparently correspond to Cu(I) and Cu(II) oxidation states. The number of overcoordinated atoms, both arsenic and sulfur, grows with increasing concentration of copper. Overcoordinated sulfur is found in trigonal planar configuration, and overcoordinated (four-fold) arsenic is in tetrahedral configuration. Addition of copper suppresses the localization of lone-pair electrons on chalcogen atoms, and localized states at the top of the valence band are due to Cu 3d orbitals. Evidently, these additional Cu states, which are positioned at the same energies as the states due to ([As4]-)-([S_3]+) pairs, are responsible for masking photodarkening in Cu chalcogenides

    Correlations between Income inequality and antimicrobial resistance.

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    Objectives: The aim of this study is to investigate if correlations exist between income inequality and antimicrobial resistance. This study's hypothesis is that income inequality at the national level is positively correlated with antimicrobial resistance within developed countries. Data collection and analysis: income inequality data were obtained from the Standardized World Income Inequality Database. Antimicrobial resistance data were obtained from the European antimicrobial Resistance Surveillance Network and outpatient antimicrobial consumption data, measured by Defined daily Doses per 1000 inhabitants per day, from the European Surveillance of antimicrobial Consumption group. Spearman's correlation coefficient (r) defined strengths of correlations of: > 0.8 as strong, > 0.5 as moderate and > 0.2 as weak. Confidence intervals and p values were defined for all r values. Correlations were calculated for the time period 2003-10, for 15 European countries. Results: income inequality and antimicrobial resistance correlations which were moderate or strong, with 95% confidence intervals > 0, included the following. Enterococcus faecalis resistance to aminopenicillins, vancomycin and high level gentamicin was moderately associated with income inequality (r= ≥0.54 for all three antimicrobials). Escherichia coli resistance to aminoglycosides, aminopenicillins, third generation cephalosporins and fluoroquinolones was moderately-strongly associated with income inequality (r= ≥0.7 for all four antimicrobials). Klebsiella pneumoniae resistance to third generation cephalosporins, aminoglycosides and fluoroquinolones was moderately associated with income inequality (r= ≥0.5 for all three antimicrobials). Staphylococcus aureus methicillin resistance and income inequality were strongly associated (r=0.87). Conclusion: as income inequality increases in European countries so do the rates of antimicrobial resistance for bacteria including E. faecalis, E. coli, K. pneumoniae and S. aureus. Further studies are needed to confirm these findings outside Europe and investigate the processes that could causally link income inequality and antimicrobial resistance

    Behavioural syndrome in a solitary predator is independent of body size and growth rate.

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    Models explaining behavioural syndromes often focus on state-dependency, linking behavioural variation to individual differences in other phenotypic features. Empirical studies are, however, rare. Here, we tested for a size and growth-dependent stable behavioural syndrome in the juvenile-stages of a solitary apex predator (pike, Esox lucius), shown as repeatable foraging behaviour across risk. Pike swimming activity, latency to prey attack, number of successful and unsuccessful prey attacks was measured during the presence/absence of visual contact with a competitor or predator. Foraging behaviour across risks was considered an appropriate indicator of boldness in this solitary predator where a trade-off between foraging behaviour and threat avoidance has been reported. Support was found for a behavioural syndrome, where the rank order differences in the foraging behaviour between individuals were maintained across time and risk situation. However, individual behaviour was independent of body size and growth in conditions of high food availability, showing no evidence to support the state-dependent personality hypothesis. The importance of a combination of spatial and temporal environmental variation for generating growth differences is highlighted

    Antibiotic consumption and antimicrobial resistance in Poland; findings and implications

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    Background: The problem of inappropriate use of antibiotics and the resulting growth in antimicrobial resistance (AMR) has implications for Poland and the world. The objective of this paper was to compare and contrast antibiotic resistance and antibiotic utilisation in Poland in recent years versus other European countries, including agreed quality indicators, alongside current AMR patterns and ongoing policies and initiatives in Poland to influence and improve antibiotic prescribing. Methods: A quantitative ten-year analysis (2007-2016) of the use of antibiotics based on European Centre for Disease Prevention and Control (ECDC) data combined with a literature review on AMR rates and antimicrobial stewardship initiatives. Results: The system of monitoring AMR and appropriate strategies to address AMR rates remain underdeveloped in Poland. The role of microbiological diagnostics and efforts to prevent infections is currently underestimated by physicians. Overall, Poland had one of the highest rates of total consumption of antibiotics in the analysed European countries. Total consumption of antibacterials for systemic use and relative consumption of beta-lactamase sensitive penicillins were characterized by small but statistically significant average annual increases between 2007 and 2016 (from 22.2DIDs to 23.9 DIDs and from 0.8% to 1.3%, respectively). Conclusions: The integrated activities around appropriate antibiotic prescribing in the pre- and post-graduate training of physicians and dentists seem to be particularly important, as well as changes in policies on prescribing antibiotics within ambulatory care. AMR and appropriate prescribing of antibiotics should be the focus of health policy actions in Poland

    Risk assessment on the impact of environmental usage of triazoles on the development and spread of resistance to medical triazoles in Aspergillus species

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    In recent years, triazole resistance in human Aspergillus diseases appears to have been increasing in several European countries. However, current data on the prevalence of resistance are based on a small number of studies which are only available from a few European countries. If present, triazole resistance can severely limit treatment options since alternatives, which are only available in intravenous form, have been shown to be associated with more side effects and poorer outcomes. Triazole resistance in Aspergillus spp. can evolve during therapy. Several point mutations, particularly in the cyp51A gene, have been associated with the development of resistance. Increasingly however, resistant isolates are also being detected in azole-naive patients. These isolates tend to have a particular genetic alteration consisting of a 34-base pair tandem repeat in the promoter coupled with a point mutation in the cyp51A target gene. This leads to an amino-acid substitution at codon 98 (TR34/L98H) causing multi-azole resistance. In patients whose Aspergillus isolates have developed resistance during azole therapy wildtype isolates, closely related genetically to the resistant isolates, have regularly been recovered from samples taken before the start of therapy or during an earlier phase. To date however, no isogenic isolate with a wild-type phenotype has been recovered from patients infected with an Aspergillus strain carrying the TR34/L98H genetic alteration. This suggests a possible environmental origin of the resistant fungus. This particular resistance mechanism has been observed most frequently in clinical isolates in the Netherlands where it has also been found in the environment. Moreover, the resistance mechanism has been demonstrated in clinical isolates in eight other European countries. Azole fungicides are widely used for crop protection and material preservation in Europe. They protect crops from disease, ensure yields and prevent fungal contamination of produce. It has been proposed that triazole resistance has evolved in the environment and could be driven by the selective pressure of azole fungicides. Although evidence supporting this hypothesis is growing, the link between the environmental use of azole fungicides and the development of triazole resistance in Aspergillus spp. is not yet proven. Triazole therapy has become the established treatment for invasive aspergillosis and is widely used in the treatment of allergic aspergillosis and chronic pulmonary aspergillosis. Antifungal therapy for invasive pulmonary aspergillosis is usually prescribed for a minimum of 6–12 weeks, but often may need to be continued for months depending on the period of immunosuppression. Treatment of allergic aspergillosis and chronic pulmonary aspergillosis may need to continue for years or even throughout a patient’s lifetime. We estimated the burden of allergic, chronic and invasive aspergillosis using population statistics and published literature. Of the 733 million inhabitants in the European region1 [1], at any one time 2 100 000 patients may be suffering from allergic aspergillosis and 240 000 from chronic aspergillosis, that would be an indication for antifungal therapy. For invasive aspergillosis, we have estimated an annual incidence of 63 250 cases, complicating multiple underlying conditions including leukaemia, transplantation, chronic obstructive pulmonary disease (COPD) and medical intensive care. The inability to treat these patients with triazoles due to multi-azole resistance would have significant impact on patient management and associated health costs. Early and thorough investigation of this emerging public health problem is warranted in order to avoid the development and spread of resistance. This report examines current evidence for the environmental origin of resistance in Aspergillus spp. and makes recommendations for further steps to assess the risks and consequences of the environmental usage of azole derivatives. Improved surveillance of clinical isolates, including antifungal susceptibility testing, is the key to a better understanding of the magnitude of this emerging problem. Furthermore, the diagnosis of Aspergillus diseases needs to be improved and molecular methods allowing detection of resistance in culture-negative specimens must be further developed and implemented in laboratory practice. Finally, further environmental and laboratory studies are needed to confirm the environmental hypothesi

    Intercomparison Exercise for Heavy Metals in PM10

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    The Joint Research Centre (JRC) has carried out an Intercomparison Exercise (IE) for the determination of heavy metals in particulate matter (PM10). The IE focussed on Lead (Pb), Arsenic (As), Nickel (Ni) and Cadmium (Cd), the heavy metals regulated by the 1st and 4th Daughter Directives for Air Pollution. Copper (Cu), Chromium (Cr) and Zinc (Zn), the elements included in the EMEP programme together with Aluminium (Al), Cobalt (Co), Iron (Fe), Manganese (Mn) and Vanadium (V) were also tested. Fourteen Laboratories, generally members of the Network of Air Quality Reference Laboratories (AQUILA), participated in the IE. The participants mainly used microwave digestion with nitric acid and hydrogen peroxide and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) or Graphite Furnace Atomic Absorption Spectrometry (GF-AAS) for analysis as recommended in the reference method (EN 14902). However, a few participants used other methods: Energy Dispersive X-ray Fluorescence (EDXRF), Atomic Emission Spectrometry (ICP-AES) and Voltammetry for analysis and vaporisation on hot plate before microwave digestion, Soxhlet extraction, high pressure or cold Hydrogen Fluoride methods for digestion. Each participant received 5 samples to be analysed: a liquid sample prepared by dilution of a Certified Reference Material (CRM), a solution of a dust CRM sample digested by the JRC13F, a sub-sample of a dust CRM that each participating laboratory had to digest and analyse, a solution prepared by JRC after digestion of an exposed filter and a pair of filters (one blank filter and one exposed filter) to be digested and analysed by each participant. For 89 % of all types of samples, the DQOs of the 1st and 4th European Directives (uncertainty of 25 % for Pb and 40 % for As, Cd and Ni) were met. All together, this is a very good score. The best results were obtained for the liquid CRM, dust CRM digested by JRC, dust CRM and filter digested by JRC with 92, 90, 96 and 93 % of DQOs being met, respectively. It was found that the DQOs were not met if the difference of acidity between test samples and participant calibration standards was high. Conversely, only 76 % of DQOs were met for the filter to be digested by each participant with (about 85 % for Cd and Ni, 73/64 % for Pb and As, the most difficult element to determine). The worst results were associated with special events: explosion in microwave oven during digestion for two participants, a wrong dilution factor used by one participant and a huge contamination in the blank filter for another participant. Among the two explosions, one of them was probably the effect of a lack of temperature control in the digestion vessel. For the other explosion, the microwave digestion and the digestion program advised by EN 14902 is to be questioned. Moreover, satisfactory results were obtained using Soxhlet extraction, high pressure method and cold Hydrogen Fluoride digestion methods which are not presented in EN 14902. The DQOs of As and Cd could not be met with EDXRF whose limit of detection was too high for these two elements and for Cd using Voltammetry which suffered a strong interference for this element. Regarding the methods of analysis, apart the points mentioned just before about EDXRF and Voltammetry, good results were observed using ICP-OES for Cd, Ni and Pb. A few discrepancies were also registered for GF-AAS and ICP-MS but they were created by the special events or acidity problem mentioned before. This shows that even though GF-AAS and ICP-MS are found suitable, the implementation by each participant may be responsible for important mistakes.JRC.H.4-Transport and air qualit

    Leviviricetes: expanding and restructuring the taxonomy of bacteria-infecting single-stranded RNA viruses

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    The vast majority of described prokaryotic viruses have double-stranded or single-stranded DNA or double-stranded RNA genomes. Until 2020, a mere four prokaryotic single-stranded, positive-sense RNA viruses have been classified in two genera (Riboviria; Lenarviricota; Allassoviricetes; Leviviridae). Several recent metagenomic and metatranscriptomic studies revealed a vastly greater diversity of these viruses in prokaryotic soil communities than ever anticipated. Phylogenetic analysis of these newly discovered viruses prompted the reorganization of class Allassoviricetes, now renamed Leviviricetes, to include two orders, Norzivirales and Timlovirales, and a total of six families, 428 genera and 882 species. Here we outline the new taxonomy of Leviviricetes, approved and ratified in 2021 by the International Committee on Taxonomy of Viruses, and describe open-access hidden Markov models to accommodate the anticipated identification and future classification of hundreds, if not thousands, of additional class members into this new taxonomic framework

    Estrogen-Eluting Stents

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    Coronary stenting is routinely utilized to treat symptomatic obstructive coronary artery disease. However, the efficacy of bare metal coronary stents has been historically limited by restenosis, which is primarily due to excessive neointima formation. Drug-eluting stents (DES) are composed of a stainless steel backbone encompassed by a polymer in which a variety of drugs that inhibit smooth muscle cell proliferation and excessive neointima formation are incorporated. DES have significantly reduced the incidence of restenosis but are also associated with a small (~0.5% per year) but significant risk of late stent thrombosis. In that regard, estrogen-eluting stents have also undergone clinical evaluation in reducing restenosis with the additional potential benefit of enhancing reendothelialization of the stent surface to reduce stent thrombosis. Estrogen directly promotes vasodilatation, enhances endothelial healing, and prevents smooth muscle cell migration and proliferation. Due to these mechanisms, estrogen has been postulated to reduce neointimal hyperplasia without delaying endothelial healing. In animal studies, estrogen treatment was effective in decreasing neointimal hyperplasia after both balloon angioplasty and stenting regardless of the method of drug delivery. The first uncontrolled human study using estrogen-coated stents demonstrated acceptable efficacy in reducing late lumen loss. However, subsequent randomized clinical trials did not show superiority of estrogen-eluting stents over bare metal stents or DES. Further studies are required to determine optimal dose and method of estrogen delivery with coronary stenting and whether this approach will be a viable alternative to the current DES armamentarium
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