Methylation of 16S ribosomal RNA (rRNA) has recently emerged as a new mechanism of resistance against aminoglycosides among gram-negative pathogens belonging to the family Enterobacteriaceae and ...glucose-nonfermentative microbes, including Pseudomonas aeruginosa and Acinetobacter species. This event is mediated by a newly recognized group of 16S rRNA methylases, which share modest similarity to those produced by aminoglycoside-producing actinomycetes. Their presence confers a high level of resistance to all parenterally administered aminoglycosides that are currently in clinical use. The responsible genes are mostly located on transposons within transferable plasmids, which provides them with the potential to spread horizontally and may in part explain the already worldwide distribution of this novel resistance mechanism. Some of these organisms have been found to coproduce extended-spectrum β-lactamases or metallo-β-lactamases, contributing to their multidrug-resistant phenotypes. A 2-tiered approach, consisting of disk diffusion tests followed by confirmation with polymerase chain reaction, is recommended for detection of 16S rRNA methylase-mediated resistance.
InAs quantum dots (QDs) are receiving attention as next‐generation E‐band light source that offers high‐temperature operation and temperature insensitive operation. However, high‐density crystal ...defects occur at the interface between the InGaAs buffer layer and GaAs, resulting in reduced device performance and shortened lifetime. Here, E‐band QD lasers are demonstrated on InGaAs buffer layer, which suppressed the spread of dislocation by introducing a high‐temperature annealing and a strained layer superlattice filter. In the device, the peak wavelength at room temperature is measured to be 1427 nm and the threshold current density was 440 A/cm2. This result indicates that E‐band QD laser structures on low threading dislocation density are promising for the realisation of high‐performance E‐band lasers.
We report elemental and Nd-Sr isotopic data for two coeval postcollisional magmatic suites (∼300 Ma), the Miaogou and Karamay suites, from West Junggar foldbelt (NW China), aiming to determine their ...source regions and implications for continental growth. The Miaogou rocks, monzonitic to granitic in composition, show low Mg# (<0.30) and depletion of HFSE, and are highly depleted in isotopic compositions, with I
Sr ranging from 0.7035 to 0.7045, ε
Nd(300 Ma) from + 8.4 to + 6.6 and young Nd model ages (0.37–0.70 Ga) that coincide with the ages of the ophiolites in the area. These features suggest that the Miaogou rocks were derived essentially by partial melting of a juvenile basaltic lower crust formed in the early to middle Palaeozoic. The Karamay suite contains a variety of rock types from gabbroic diorite to granite. These rocks show enrichment of LREE and LILE and depletion of HFSE, and have chemical composition (e.g., Mg# = 0.63–0.41) rather different from the Miaogou suite, though isotopically they are indistinguishable. This suggests that the parental magma of the Karamay suite originated from melting of a young lithospheric mantle that had previously been metasomatized during the Palaeozoic subduction. The West Junggar magmatic rocks represent production of juvenile continental crust in the Phanerozoic, triggered by upwelling of asthenophere in an extensional regime. The basement beneath the area is dominated by “trapped” Palaeozoic arc series and oceanic crust.
III-nitride quantum dots are proving to be promising for application to single photon emitting devices. Research around the globe is revealing several interesting properties of these emitters, ...including a wide range of emission wavelengths, high temperature operation, and deterministic polarization of the emitted photons. Here a review is given on the single photon emission properties of such III-nitride quantum dots.
The unique emission properties of single-walled carbon nanotubes are attractive for achieving increased functionality in integrated photonics. In addition to being room-temperature telecom-band ...emitters that can be directly grown on silicon, they are ideal for coupling to nanoscale photonic structures. Here we report on high-efficiency coupling of individual air-suspended carbon nanotubes to silicon photonic crystal nanobeam cavities. Photoluminescence images of dielectric- and air-mode cavities reflect their distinctly different mode profiles and show that fields in the air are important for coupling. We find that the air-mode cavities couple more efficiently, and estimated spontaneous emission coupling factors reach a value as high as 0.85. Our results demonstrate advantages of ultralow mode-volumes in air-mode cavities for coupling to low-dimensional nanoscale emitters.
This paper reviews the recent progress of quantum-dot semiconductor optical amplifiers developed as ultrawideband polarization-insensitive high-power amplifiers, high-speed signal regenerators, and ...wideband wavelength converters. A semiconductor optical amplifier having a gain of > 25 dB, noise figure of < 5 dB, and 3-dB saturation output power of > 20 dBm, over the record widest bandwidth of 90 nm among all kinds of optical amplifiers, and also having a penalty-free output power of 23 dBm, the record highest among all the semiconductor optical amplifiers, was realized by using quantum dots. By utilizing isotropically shaped quantum dots, the TM gain, which is absent in the standard Stranski-Krastanow QDs, has been drastically enhanced, and nearly polarization-insensitive SOAs have been realized for the first time. With an ultrafast gain response unique to quantum dots, an optical regenerator having receiver-sensitivity improving capability of 4 dB at a BER of 10 -9 and operating speed of > 40 Gb/s has been successfully realized with an SOA chip. This performance achieved together with simplicity of structure suggests a potential for low-cost realization of regenerative transmission systems.
Summary
Background
Behçet disease (BD) presents with lymphocytic and neutrophilic vasculitis of unknown aetiology. HLA‐B*51, the endoplasmic reticulum aminopeptidase 1 (ERAP1), and interleukin 23 ...receptor (IL23R)/IL12R are genetic risk factors. IL‐23 regulates IL‐17A, which controls the recruitment and activation of neutrophils.
Objectives
To determine pathological changes in BD skin lesions related to the complex genetic predisposition.
Methods
We characterized the expression of IL‐17A and IL‐23A in various cell types by immunohistological double staining of sections from papulopustular skin lesions of acute attacks of BD and psoriasis vulgaris lesions, another HLA‐class I‐associated T‐cell‐mediated autoimmune disease in which excessive T‐cell‐derived IL‐17A production promotes neutrophil activation.
Results
We found that in BD lesions, as in psoriasis, actively expanding CD8+ T cells were the predominant source of IL‐17A. IL‐17A+ CD8+ T (Tc17) cells outnumbered infiltrating IL‐17A+ CD4+ T cells. Unlike the epidermal localization of CD8+ T cells in psoriasis, Tc17 cells in BD lesions mainly infiltrated the perivascular tissue and the blood vessel walls of dermis and subcutaneous tissue. They co‐localised with a marked IL‐23A expression by CD11c+ dendritic cells and CD68+ macrophages. IL‐17A expression was associated with extensive recruitment of neutrophils around blood vessels that formed neutrophil extracellular traps (NETs).
Conclusions
In BD, the genetic predisposition may mediate antigen‐specific activation and differentiation of a Tc17 response, possibly targeting endothelial (auto)antigens. Neutrophils recruited by IL‐17A in this process may enhance tissue damage by extensive NET formation (NETosis). Thus, the IL‐23/IL‐17 axis presumably controls neutrophilic inflammation in BD vasculitis in the context of a predominant antigen‐specific CD8+ T‐cell response.
What is already known about this topic?
Behçet disease (BD) is a systemic vasculitis of unknown aetiology.
HLA‐B*51 and the endoplasmic reticulum aminopeptidase 1 (ERAP1), which cooperate in antigen processing and presentation to CD8+ T cells, and interleukin 23 receptor (IL23R)/IL12R are the main risk genes.
IL‐17A is thought as a key cytokine in BD, which is produced under the control of IL‐23 and activates neutrophils.
What does this study add?
As a clinical correlate of the risk association with HLA‐B*51, ERAP1, and IL23R/IL12R, activated CD8+ T cells in the acute papulopustular skin lesions of BD massively express IL‐17A under the control of IL‐23A, which is expressed mainly by CD11c+ dendritic cells with a histiocytic morphology.
Lymphocytic vasculitis by IL‐17A+ CD8+ T (Tc17) cells in BD presumably mediates neutrophil recruitment and prominent neutrophil extracellular trap (NET) release.
These data reveal that, as in psoriasis, potentially autoreactive CD8+ T cells with marked IL‐17A production play an important pathogenic role in BD.
What is the translational message?
The results may link three major BD risk genes in a pathogenic concept, in which HLA‐B*51‐restricted endoplasmic reticulum aminopeptidase 1‐dependent antigens activate a CD8+ T‐cell response whose IL‐17A production is enhanced by an IL‐23R risk variant, leading to neutrophil recruitment and NET formation (NETosis).
These findings may inspire therapeutic interventions targeting the IL‐17/IL‐23 axis or NETosis to resolve or suppress attacks of BD.
An IL‐23‐driven Tc17 response dominates in skin lesions of Behcet’s disease.
Plain language summary available online
We fabricated optical directional couplers with Si-wire waveguides and demonstrated their fundamental characteristics. Their coupling-length was extremely short, several micrometers, because of ...strong optical coupling between the waveguide cores. Wavelength demultiplexing functions were also demonstrated for devices with a long coupled waveguide. Optical output from a device 800 μm long changed reciprocally with 2.5-nm wavelength spacing between the parallel and cross ports.
To investigate the prevalence of plasmid-mediated fosfomycin resistance determinants among extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae and their genetic ...environments. A total of 347 non-duplicate ESBL-producing E. coli (165) and K. pneumoniae (182) were collected. The fosfomycin MICs were determined by the agar dilution method according to CLSI guidelines. PCR was used to detect the plasmid-encoded fosfomycin resistance genes (fosA, fosA3, fosB and fosC2). For isolates harbouring plasmid-encoded fosfomycin resistance genes, sequence types (STs) were determined. The transformation experiment was performed using E. coli TOPO10 (Invitrogen, USA) as a recipient strain. With the plasmids from the transformants, plasmid replicon typing was performed and the nucleotide sequences adjacent to fosA3 were determined. The susceptibility to fosfomycin was 92.9% in E. coli and 95.2% in K. pneumoniae. Of the 21 isolates non-susceptible to fosfomycin (8 E. coli and 13 K. pneumoniae), 7 (5 E. coli and 2 K. pneumoniae) isolates harboured fosA3 and all of them co-harboured bla... or bla... The STs of the isolates harbouring fosA3 were diverse (E. coli: ST1, ST1, ST533, ST2 and ST86; K. pneumoniae: ST11 and ST101). The plasmid replicon types of transformants co-harbouring bla... and bla... were IncF and IncN, respectively. By sequence analysis, we found the common feature that the fosA3 gene, connected to bla... via insertion sequences, was located between two IS26 elements oriented in the opposite direction, composing an IS26-composite transposon. An IS26-composite transposon appears to be the main vehicle for dissemination of fosA3 in E. coli and K. pneumoniae of diverse clones. (ProQuest: ... denotes formulae/symbols omitted.)
The below-gap emission components including yellow luminescence (YL) band of an MOCVD grown undoped GaN have been studied by the two-wavelength-excited photoluminescence (TWEPL). The nature of each ...emission line has been investigated by using an intermittent below-gap excitation (BGE) light of 1.17 eV on an above-gap excitation (AGE) light of 3.49 eV. The intensity of DAP and the YL decreased while it increased for IOX after irradiation of the BGE. The intensity change in PL after addition of the BGE implies the presence of defect levels in the energy position corresponding to the photon energy of the BGE. Possible recombination models are listed and examined. Only the recombination model in which the YL corresponds to the transition from a shallow donor to a deep state at about 1 eV above the valence band maximum satisfies our experimental result. The possible origin of this defect state is discussed.
•Undoped GaN grown by MOCVD on the sapphire substrate.•Optical properties of undoped GaN were investigated by our special scheme of Two-wavelength Excited Photoluminescence (TWEPL).•The omnipresent yellow luminescence (YL) in the GaN is assigned to a transition of the shallow donor to the deep state.•The YL band has been allocated about 1 eV above the valence band maximum.•Origin of the YL band is discussed and correlated with previous reports.
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