Nanocrystal growth and morphology of PbTeSe-ZnSe composite thin films prepared by one-step synthesis method

The microstructure of polycrystalline PbTe₁₋ₓSeₓ-ZnSe composite thin films has been studied by scanning transmission electron microscopy and electron diffraction. The films were prepared by the one-step synthesis method using simultaneous evaporation of PbTe and ZnSe. The nanocrystals of PbTe₁₋ₓSeₓ are formed in a ZnSe matrix. Tellurium concentration can be tuned by controlling the PbTe evaporation source temperatures between 753 K and 793 K. Binary PbSe nanocrystals were formed at 753 K, while ternary PbTe₁₋ₓSeₓ nanocrystals were formed at 793 K. The nanocrystals grow in a granular shape at the initial stage of film growth, and the morphology changes to nanowire-shape as the film grows, irrespective of the Te concentration. The ternary PbTe₁₋ₓSeₓ nanocrystals were composed of two phases with different Te concentration; Te-rich (Se-poor) granular crystals were formed near the bottom half parts of the film and Te-poor (Se-rich) nanowires were formed at the upper half parts of the film. Columnar ZnSe crystals contain high-density {111} stacking faults due to the low stacking fault energy of ZnSe. A balance of deposition and re-evaporation on the substrate during the film growth will be responsible for the resultant nanocrystal morphology.Kazuhisa Sato and Seishi Abe, "Nanocrystal growth and morphology of PbTeSe-ZnSe composite thin films prepared by one-step synthesis method", Journal of Applied Physics 120, 155301 (2016) https://doi.org/10.1063/1.496487

One-step synthesis of PbSe-ZnSe composite thin film

This study investigates the preparation of PbSe-ZnSe composite thin films by simultaneous hot-wall deposition (HWD) from multiple resources. The XRD result reveals that the solubility limit of Pb in ZnSe is quite narrow, less than 1 mol%, with obvious phase-separation in the composite thin films. A nanoscale elemental mapping of the film containing 5 mol% PbSe indicates that isolated PbSe nanocrystals are dispersed in the ZnSe matrix. The optical absorption edge of the composite thin films shifts toward the low-photon-energy region as the PbSe content increases. The use of a phase-separating PbSe-ZnSe system and HWD techniques enables simple production of the composite package

The Leiognathus splendens complex (Perciformes: Leiognathidae) with the description of a new species, Leiognathus kupanensis Kimura and Peristiwady

Taxonomic analysis of a group of morphologically similar ponyfishes (Perciformes: Leiognathidae) establishes the Leiognathus splendens complex comprising four valid species: L. jonesi James, 1971, widely distributed in the Indo-West Pacific, from Mauritius to Papua New Guinea, north to Hainan I. (China), and south to Brisbane, Australia; L. kupanensis sp. nov., currently known only from Kupang, Timor, Indonesia; L. rapsoni Munro, 1964, currently known only from India, Indonesia, and Papua New Guinea, and L. splendens Cuvier, 1829, widely distributed in the eastern Indian and western Pacific oceans, from India to Papua New Guinea, and from southern Japan to northern Australia. The L. splendens complex can be defined by the following combination of characters: body depth 42–60% of standard length; mouth protruding downward; slender, minute teeth uniserially on jaws; lower margin of orbit above the horizontal through the gape when mouth closed; breast almost completely scaled; lateral line complete, and a dark blotch on top of spinous dorsal fin. Diagnostic characters of the members are as follows: L. jonesi —anterior dorsolateral body surface with a semicircular naked area on nape, and a paler dark blotch on spinous dorsal fin; L. kupanensis —anterior dorsolateral body surface widely naked; L. rapsoni —cheek scaled; L. splendens —anterior dorsolateral body surface completely scaled and a jet black blotch on spinous dorsal fin.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41595/1/10228_2005_Article_283.pd

The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force

「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection

DOCK2 is involved in the host genetics and biology of severe COVID-19

「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target

Correlation between crystallite size, resistance to oxidation, and phase transformation of germanium-doped Fe3O4 nanocrystalline thin films by using a sputtering target of α-Fe2O3

We investigated the correlation between the crystallite size, resistance to oxidation, and phase transition of Ge-doped Fe3O4 nanocrystalline thin films. We prepared thin films on water-cooled glass substrates by radiofrequency sputtering with Ge-tipped α-Fe2O3 ceramic disks as targets. The addition of Ge caused a reductive phase transition from α-Fe2O3 with a corundum structure to Ge-doped Fe3O4 with an inverse spinel structure, resulting in a crystallite size of <10 nm. We annealed three samples with average sizes of 5, 8, and 10 nm by changing Ge addition concentrations at 673 K in air for up to 323 days until reaching near-thermal equilibrium. All samples maintained their magnetization at almost a constant value over long-term heat treatment. The results of Raman spectroscopy and optical transmittance spectroscopy suggest that there was a phase transition to Ge-doped γ-Fe2O3 at 5 nm, Ge-doped Fe3−δO4 with iron vacancies δ at 8 nm, and Ge-doped Fe3O4 at 10 nm. In other words, we retained Fe3O4 down to a relatively small crystallite size of 10 nm because of the improved oxidation resistance imparted by Ge doping

Nanocomposite thin films containing Pt nanoparticles dispersed in an α-Fe2O3 matrix by RF sputtering

The preparation of nanocomposite thin films that phase-separate Pt and α-Fe2O3 was investigated. These films were prepared on water-cooled glass substrates by radio frequency sputtering in an Ar atmosphere. X-ray diffraction patterns reveal that iron oxide forms Fe3O4 in the as-deposited state and undergoes a phase transition to α-Fe2O3 after heat treatment in the air. Pt is phase-separated from iron oxides in the as-deposited state and during heat treatment in the air, with a crystallite size of less than 2 nm in the as-deposited state, which varies between 2 and 15 nm after heat treatment in the air, estimated from the x-ray diffraction peaks. High-resolution transmission electron microscopy of the sample after heat treatment in the air reveals that spherical particles with a relatively uniform size are dispersed, which are assigned to Pt from fast Fourier transform analysis, while the surrounding area is assigned to α-Fe2O3. Thus, the thin film forms a nanocomposite thin film in which Pt nanoparticles are dispersed in α-Fe2O3