Hydrogen-assisted fabrication of spherical gold nanoparticles through sonochemical reduction of tetrachloride gold(III) ions in water

Spherical gold nanoparticles (AuNPs) were selectively synthesized through sonochemical reduction of tetrachloride gold(III) ions ([AuCl4](-)) in an aqueous solution of hydrogen tetrachloroaurate(III) tetrahydrate (HAuCl4.H2O) with the aid of hydrogen (H-2) gas in the absence of any additional capping agents. On the other hand, various shaped-AuNPs such as spherical nanoparticles, triangular and hexagonal plates were formed from sonochemical reduction of [AuCl4](-) in argon (Ar)-, nitrogen (N-2)- or oxygen (O-2)-purged aqueous [AuCl4](-) solutions. The selective fabrication of spherical AuNPs assisted by H-2 gas is most likely attributed to the generation of hydrogen radicals (H center dot) promoted by the reaction of H-2 introduced and hydrogen oxide radicals (center dot OH) produced by sonolysis of water.ArticleULTRASONICS SONOCHEMISTRY. 21(3):946-950 (2014)journal articl

Surfactant- and reducer-free synthesis of gold nanoparticles in aqueous solutions

We report here the surfactant- and reducer-free synthesis of gold nanoparticles from an aqueous hydrogen tetrachloroaurate (III) tetrahydrate (HAuCl(4)center dot 4H(2)O) solution using a high-frequency (950 kHz) ultrasound (in the absence of any stabilizing, capping and reducing agents). In particular, size, shape and stability of gold nanoparticles prepared by the 950 kHz ultrasound irradiation (sonication) for 8 min in the surfactant-free aqueous solutions were examined in terms of AuCl(4)(-) concentration (in the range of 0.01-0.1 mM), additional salts (NaCl, HCl and NaOH) and temperature (in the range of 4-60 degrees C). We found that higher AuCl(4)(-) concentration promoted particle growth (size increase) and plate formation. In addition, the plate formation was enhanced with the addition of NaCl or HCl (but not NaOH). This is most likely due to the AuCl(4)(-) reduction on a certain crystal facets (e.g. (1 1 0) facets) caused by the adsorption of Cl(-) ions on specific crystal facets (e.g. (1 1 1) facets). Furthermore, we revealed that the temperature elevated above 50 degrees C led to the formation of spherical gold nanoparticles with the diameter of 20-60 nm from a 0.1 mM AuCl(4)(-) aqueous solution while triangular plates formed coexisting with spherical nanoparticles below 50 degrees C.ArticleCOLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS. 347(1-3):18-26 (2009)journal articl

Hydrogen-assisted fabrication of spherical gold nanoparticles through sonochemical reduction of tetrachloride gold(III) ions in water

Spherical gold nanoparticles (AuNPs) were selectively synthesized through sonochemical reduction of tetrachloride gold(III) ions ([AuCl4](-)) in an aqueous solution of hydrogen tetrachloroaurate(III) tetrahydrate (HAuCl4.H2O) with the aid of hydrogen (H-2) gas in the absence of any additional capping agents. On the other hand, various shaped-AuNPs such as spherical nanoparticles, triangular and hexagonal plates were formed from sonochemical reduction of [AuCl4](-) in argon (Ar)-, nitrogen (N-2)- or oxygen (O-2)-purged aqueous [AuCl4](-) solutions. The selective fabrication of spherical AuNPs assisted by H-2 gas is most likely attributed to the generation of hydrogen radicals (H center dot) promoted by the reaction of H-2 introduced and hydrogen oxide radicals (center dot OH) produced by sonolysis of water.ArticleULTRASONICS SONOCHEMISTRY. 21(3):946-950 (2014)journal articl

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

Quantum-enhanced optical beat-note detection beyond 3-dB noise penalty of image band

Optical beat-note detection with two beams at different frequencies is a key sensing technology for various spatial/temporal measurements. However, its sensitivity is inherently susceptible to shot noise due to the extra shot-noise contamination from the image band known as the 3-dB noise penalty, as well as the unavoidable optical power constraints at detectors. Here, we propose a method to remove shot noise from all relevant bands including the extra noise by using squeezed light. We also demonstrate beyond-3-dB noise reduction experimentally. Our work should boost the sensitivity of various spatial/temporal measurements beyond the current limitations.Comment: 5 pages and 4 figures for the main text, and 3 pages and 3 figures for the supplementary informatio

Detection of Hypervascular Hepatocellular Carcinoma With Multidetector-Row CT: Single Arterial-Phase Imaging With Computer-Assisted Automatic Bolus-Tracking Technique Compared With Double Arterial-Phase Imaging

Purpose: To compare single arterial-phase (SAP) computed tomography (CT) imaging with bolus tracking (BT) with double arterial-phase (DAP) CT imaging for detecting hypervascular hepatocellular carcinoma