Oxacillinase (OXA)-48-like carbapenemases remain relatively uncommon in the United States. We performed phenotypic and genotypic characterization of 30 Enterobacteriaceae producing OXA-48-like ...carbapenemases that were recovered from patients during 2010-2014. Isolates were collected from 12 states and not associated with outbreaks, although we could not exclude limited local transmission. The alleles β-lactamase OXA-181 (bla
) (43%), bla
(33%), and bla
(23%) were found. All isolates were resistant to ertapenem and showed positive results for the ertapenem and meropenem modified Hodge test and the modified carbapenem inactivation method; 73% showed a positive result for the Carba Nordmann-Poirel test. Whole-genome sequencing identified extended-spectrum β-lactamase genes in 93% of isolates. In all bla
isolates, the gene was on a ColKP3 plasmid. A total of 12 of 13 isolates harboring bla
contained the insertion sequence ΔISEcp1. In all isolates with bla
, the gene was located on a TN1999 transposon; these isolates also carried IncL/M plasmids.
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DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Proton exchange membrane (PEM) fuel cells are at the dawn of commercialization. Their operation and design characteristics, hence their performance, are closely linked to the multiphase transport of ...mass, heat, and electricity in the cell constituents, a critical of which is the gas diffusion layer (GDL). The GDL's transport capability is represented by its effective transport properties: an effective diffusion coefficient for the diffusional transport of mass, absolute and relative permeabilities for the convective transport of mass, effective thermal conductivity for the heat transport, and effective electron conductivity for the electricity transport; in addition, surface wettability impacts the transport of liquid water. These transport properties depend on the GDL's mechanical, morphological, microstructural, and physical characteristics, which are in turn controlled by its materials and design parameters. This review article therefore focuses on the insights and comprehensive understanding of three critical issues of the GDLs: (i) their morphological, microstructural, and physical characteristics, (ii) ex- and in-situ characterization techniques for the determination of their effective transport and mechanical properties, and (iii) frequently used materials and design strategies and their relevant influences on the effective transport properties in order to achieve reliable and durable performance of PEM fuel cells with high power densities.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The reliance on plastic for a vast number of consumer products, many of them single-use, results in their continuous entry into aquatic environments. Plastic waste can fragment into smaller debris, ...some with a diameter < 5 mm (microplastics). Microplastics are of growing concern especially since 2014, however to date research on microplastic pollution has mainly focused on marine environments, partly because it has been mistakenly thought that sewage treatment plants could remove all plastic debris. To understand the impact of microplastic pollution in freshwater environments, an assessment of research on the sources, distribution and effects of microplastics, and trends in their analysis and policy has been carried out. Main sources of microplastic found in freshwater environments include synthetic textiles, personal care products, industrial raw materials and the improper disposal of plastic waste. Microplastic pollution is a global issue that presents with a broad range of concentration: for example, 3.5 × 10^3 microplastic units·L−1 were reported in sediment of Lake Huron, in the US and as low as 1.2×10−4 units·L−1 in countries with sparse population such as Mongolia. The main polymer constituents of microplastics found in freshwaters have been identified as polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET), accounting for 70% of the total, each with a very similar frequency of occurrence. Despite microplastics being relatively inert, they are found to cause some effects in aquatic organisms. Future work should focus on monitoring microplastic pollution in regions from where there is currently scarce published data (e.g. South America, Africa and North Asia) and the study of their sources, stability, transport and effects to freshwater ecosystems. The establishment of standardized monitoring methods will allow for the comparison of data from different geographic areas. This information will inform measures to reduce the release and occurrence of microplastics in aquatic environments.
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•In freshwater, microplastics suffer weathering and distribute around their source.•Effluents from sewage treatment plants, laundry and litter release microplastics.•Fibres are the main type of microplastic in freshwater, followed by fragments.•No high throughput monitoring methods and lack of harmonisation.•Undefined toxicity with a trend showing it is affected by size and shape.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Potentially safe and economically feasible magnesium batteries (MBs) have attracted tremendous research attention as an alternative to high-cost and unsafe lithium ion batteries. In the current work, ...for the first time, we report a novel room-temperature approach to dope the atomic species sodium between the vanadium oxide crystal lattice to obtain NaV3O8·1.69H2O (NVO) nanobelts. The synthesized NVO nanobelts are used as electrode materials for MBs. The MB cells demonstrate stable discharge specific capacity of 110 mA h g–1 at a current density of 10 mA g–1 and a high cyclic stability, that is 80% capacity retention after 100 cycles, at a current density of 50 mA g–1. Moreover, the effects of cutoff voltages (ranging from 2 to 2.6 V) on their electrochemical performance were investigated. The reason for the limited specific capacity of MBs is attributed to the trapping of Mg ions inside the NVO lattices. This work opens up a new pathway to explore different electrode materials for MBs with improved electrochemical performance.
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35.
Current opinion: What is a nanoplastic? Gigault, Julien; Halle, Alexandra ter; Baudrimont, Magalie ...
Environmental pollution (1987),
April 2018, 2018-Apr, 2018-04-00, 20180401, 2018-04-01, Volume:
235
Journal Article
Peer reviewed
With the large amount of attention being given to microplastics in the environment, several researchers have begun to consider the fragmentation of plastics down to lower scales (i.e., the ...sub-micrometer scale). The term “nanoplastics” is still under debate, and different studies have set the upper size limit at either 1000 nm or 100 nm. The aim of the present work is to propose a definition of nanoplastics, based on our recently published and unpublished research definition of nanoplastics. We define nanoplastics as particles unintentionally produced (i.e. from the degradation and the manufacturing of the plastic objects) and presenting a colloidal behavior, within the size range from 1 to 1000 nm.
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•No current opinion is given in the literature debating the word “nanoplastics”.•The misuse of the prefix “nano” could lead to unrepresentative results.•We propose a definition of nanoplastics as a basis for discussion.•Nanoplastics are particles resulting from the degradation of plastic objects.•Nanoplastics exhibit a colloidal behavior within size ranging from 1 to 1μm.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Digital Image Correlation (DIC) is an important and widely used non-contact technique for measuring material deformation. Considerable progress has been made in recent decades in both developing new ...experimental DIC techniques and in enhancing the performance of the relevant computational algorithms. Despite this progress, there is a distinct lack of a freely available, high-quality, flexible DIC software. This paper documents a new DIC software package Ncorr that is meant to fill that crucial gap. Ncorr is an open-source subset-based 2D DIC package that amalgamates modern DIC algorithms proposed in the literature with additional enhancements. Several applications of Ncorr that both validate it and showcase its capabilities are discussed.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Natural polysaccharides are critical to a wide range of fields (e.g., medicine, food production, and cosmetics) for their various remarkable physical properties and biological activities. However, ...the bioactivities of naturally acquired polysaccharides may be unsatisfactory and limit their further applications. It is generally known that the chemical structure exhibited by polysaccharides lays the material basis for their biological activities. Accordingly, possible structural modifications should be conducted on polysaccharides for their enhancement. Recently, polysaccharides complexed with metal ions (e.g., Fe, Zn, Mg, Cr, and Pt) have been reported to be possibly used to improve their bioactivities. Moreover, since the properties exhibited by metal ions are normally conserved, polysaccharides may be endowed with new applications. In this review, the synthesis methods, characterization methods, and bioactivities of polysaccharide metal complexes are summarized specifically. Then, the application prospects and limitations of these complexes are analyzed and discussed.
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The atmospheric hydroformylation of olefins with FA as syngas alternative over L1-Rh(acac)CO)2 catalytic system (L1 = Xantphos)
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•Rh-catalyzed hydroformylation of olefins with formic ...acid as syngas alternative.•Insight into decomposition of formic acid to CO as well as H2.•Characterizations by in situ FT-IR and high-pressure 1H NMR spectroscopic techniques.
Formic acid (FA) is one kind of important bulk chemicals, which is recognized as a sustainable and eco-friendly energy carrier to transport H2 via dehydrogenation or CO via decarbonylation. Expectantly, FA upon decomposition into H2 and CO could be used as the syngas alternative for hydroformylation. In this paper, the behaviors of FA to release H2 as well as CO following the distinct pathways were carefully investigated for the first time, and then established a new hydroformylation protocol free of syngas. It was found that the atmospheric hydroformylation of olefins with formic acid (FA) as syngas alternative was smoothly fulfilled over Xantphos (L1) modified Rh-catalyst under mild conditions (80 °C, Rh concentration 1 mol %, 14 h), resulting in >90% conversion of the olefins along with the high selectivity to the target aldehydes (>93%). By using FA as syngas source, the side-reaction of olefin-hydrogenation was greatly depressed. The in situ FT-IR and the high-pressure 1H NMR spectroscopic analyses were applied to reveal how FA behaves dually as CO surrogate and hydrogen source over L1-Rh(acac)(CO)2 catalytic system, based on which the deeply insight into the catalytic mechanism of hydroformylation of olefins with FA as syngas alternative was offered.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The international ISO Standard 20579‐4, dealing with the history and preparation of nano‐objects for surface analysis, has been developed to help address some of the replication and reproducibility ...issues caused by the fundamental nature of nano‐objects. Although all types of samples requiring surface analysis need thoughtful preparation, nano‐objects, for which many properties are controlled by their surfaces, present additional challenges in order to avoid variations and artefacts due to the handling and preparation of materials prior to analysis. This international standard is part of a series of standards related to preparation of samples for surface chemical analysis. Parts 1 and 2 of ISO Standard series 20579 address general issues that apply to many samples. Part 3, which is still in development, will focus on biomaterials. Part 4 specifically considers issues that arise due to the inherent nature of nano‐objects. Because of sensitivity to their environment, the standard indicates the minimum information that needs to be reported about the handling and preparation of nano‐objects prior to surface analysis. This information should become part of sample provenance information that helps assure the reliability and usefulness of data obtained from surface‐analysis in the context of the synthesis, processing, and analysis history of a batch of material. Application of this standard can help address reproducibility and traceability issues associated with synthesis, processing, and characterization of nano‐objects in research and commercial applications.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this work, a 3D printed polymer-metal soft-magnetic composite was developed and characterized for its material, structural, and functional properties. The material comprises acrylonitrile ...butadiene styrene (ABS) as the polymer matrix, with up to 40 vol. % stainless steel micropowder as the filler. The composites were rheologically analyzed and 3D printed into tensile and flexural test specimens using a commercial desktop 3D printer. Mechanical characterization revealed a linearly decreasing trend of the ultimate tensile strength (UTS) and a sharp decrease in Young's modulus with increasing filler content. Four-point bending analysis showed a decrease of up to 70% in the flexural strength of the composite and up to a two-factor increase in the secant modulus of elasticity. Magnetic hysteresis characterization revealed retentivities of up to 15.6 mT and coercive forces of up to 4.31 kA/m at an applied magnetic field of 485 kA/m. The composite shows promise as a material for the additive manufacturing of passive magnetic sensors and/or actuators.
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