33 research outputs found

    Enhanced resonant force between two entangled identical atoms in a photonic crystal

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    We consider the resonant interaction energy and force between two identical atoms, one in an excited state and the other in the ground state, placed inside a photonic crystal. The atoms, having the same orientation of their dipole moment, are supposed prepared in their symmetrical state and interact with the quantum electromagnetic field. We consider two specific models of photonic crystals: a one-dimensional model and an isotropic model. We show that in both cases the resonant interatomic force can be strongly enhanced by the presence of the photonic crystal, as a consequence of the modified dispersion relation and density of states, in particular if the transition frequency of the atoms is close to the edge of a photonic gap. Differences between the two models considered of photonic crystal are discussed in detail, as well as comparison with the analogous system of two impurity atoms in a quantum semiconductor wire. A numerical estimate of the effect in a realistic situation is also discussed.Comment: 8 page

    THEORETICAL ESTIMATION OF MECHANICAL PROPERTIES OF PLYWOOD-SHEATHED SHEAR WALL WITH COMBINED USE OF ADHESIVE TAPE AND WOOD DOWELS

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    Shear walls often function as elements that provide resistance to horizontal external forces exerted on wooden frames. Many shear walls with superior strength performance have been developed for this purpose. Amidst this backdrop, we have attempted to develop a shear wall that, in addition to strength performance, decreases the time and labor required for disposal. More specifically, the authors proposed a novel “metalless” shear wall: a shear wall in which industrial double-sided adhesive tape is used to attach plywood to the framework. Also, wood dowels are used as supplementary connectors with the aim of enhancing strength performance. Unlike conventional shear walls that use nails and metal fixtures, separation at the time of disposal is unnecessary, and therefore, disposal time and labor of the wall are anticipated to be significantly decreased. Thus, this study involved demonstrating and verifying a methodof theoretical analysis for the mechanical performance of these kinds of shear walls toward in-plane shear force. Specifically, this study derived a method to estimate the mechanical behavior (load-deformation angle relationship) of plywood-sheathed shear walls based on shear performance obtained from double shear tests of joint specimens with the combined use of adhesive tape and wood dowels. Also, the validity of the method was experimentally verified. The results showed that the method proposed in this study was able to estimate the mechanical behavior and mechanical properties of the newly proposed shear wall, and the validity of the method was confirmed

    Compressive Deformation Process of Japanese Cedar (Cryptomeria Japonica)

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    We examined the compressive deformation behavior, and methods of compression fixation were considered. Furthermore, we examined the mechanical characteristics of compressed wood for each method of fixation and each compression ratio. As a result of the examination, the deformation behavior was found to differ depending on the direction of compression. The deformation progressed without causing destruction in compression into the tangential surface, but compression into the radial surface caused partial buckling of the cell walls in the process of deformation. The compression stress showed the tendency to decrease as the temperature and moisture content increased. Steam treatment by the closed heating method was compared with heat treatment by the open heating method as methods of fixation. The closed heating method was found to be effective for deformation fixation in a short time. As the result of the mechanical properties of compressed wood, the moduli of rupture (MOR) and elasticity (MOE) increased as the compression ratio increased, and they showed the tendency to be roughly proportional to the increase in density. However, hardness increased only nominally up to 40 % compression and then increased rapidly from 40 %. Moreover, in 480-min heat treatment by open heating, the influence of heat deterioration on impact-absorbed energy was found

    ENERGETICS APPROACH TO FATIGUE BEHAVIOR OF WOODEN JOINT USING DOUBLE-SIDED ADHESIVE TAPE

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    The authors have previously studied the possibility of the use of industrial double-sided adhesive tape as a method for jointing wooden panel to wooden framework. The mechanical performance of joints formed by such methods is comparable to that of nailed joint under static load conditions. However, the mechanical performance of such joints has not been evaluated under cyclic load conditions. This study was conducted to investigate this aspect of their performance. Double-shear specimens were prepared by bonding wooden panel to wooden framework using two types of adhesive tape with different substrates. Specimens were also prepared with wooden dowels to strengthen their jointing performance. The joint specimens were subjected to cyclic shear loading testing. The results of the tests were analyzed from an energetics perspective, and the shear deformability of the specimens at failure was estimated. The test results indicate that both the specimens formed using adhesive tape and those formed using wooden dowels had fatigue properties comparable to nailed joint specimens. A tendency for the shear deformability caused by cyclic loading to increase with the stress level was observed. It was possible to estimate the shear deformability by evaluating the energy absorption capacity of the joints from an energetics standpoint

    Case Report: The importance of early intervention for gastroesophageal reflex disease caused by hiatal hernia

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    BackgroundGastroesophageal reflux (GER) disease (GERD) is a condition wherein GER causes troublesome symptoms that can affect daily functioning and/or clinical complications within the esophagus or other systems. To avoid this, patients with GERD often require treatment; hence, it is important to distinguish GER from GERD. Patients with GERD exhibiting alarm signs should be examined early to differentiate it from GER and treated accordingly. Herein, we present a case of GERD caused by a hiatal hernia that required surgical intervention for esophagial cicatrical stenosis despite oral treatment. We also discussed how to choose the appropriate acid suppressants for GERD.Case presentationA 1-year-old boy was referred to our hospital for repeated vomiting and poor weight gain. He received histamine 2 receptor antagonists (H2RAs) that contributed slightly to the decreased frequency of vomiting and aided weight gain; however, he soon stopped gaining weight and had bloody vomit. His upper gastrointestinal series revealed hiatal hernia, a 24 h impedance pH monitoring test indicated abnormal values for acid reflux, and esophagogastroduodenoscopy (EGD) revealed esophagitis. He was subsequently diagnosed with GERD associated with hiatal hernia. A proton pump inhibitor (PPI) was intravenously administered to him, following which his medication was changed to a potassium-competitive acid blocker (P-CAB). Thereafter, his vomiting episodes significantly decreased and his weight increased. However, 6 months after starting P-CAB, his vomiting episodes suddenly increased in frequency. EGD revealed the presence esophageal stricture due to scarring from GERD. He was then treated via laparoscopic fundoplication, gastrostomy, and esophageal balloon dilation. Thereafter, his vomiting episodes stopped and food intake improved, leading to weight gain.ConclusionIt is essential to identify the cause of GERD early and take an appropriate treatment approach depending on the cause of GERD with alarm signs. Further, as a drug therapy for GERD as a clear acid mediated disease or in children with alarm signs, PPIs or P-CAB should be used from the beginning instead of H2RAs

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

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    「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

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

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    「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
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