41 research outputs found
DETC2005-85137 RELIABILITY-BASED TOPOLOGY OPTIMIZATION CONSIDERING MULTICRITERIA USING FRAME ELEMENTS
ABSTRACT Since decision-making at the conceptual design stage critically affects final design solutions at the detailed design stage, conceptual design support techniques are practically mandatory if the most efficient realization of optimal designs is desired. Topology optimization methods using discrete elements such as frame elements enable a useful understanding of the underlying mechanics principles of products, however the possibility of changing prior assumptions concerning utilization environments exists since the detailed design process starts after the completion of conceptual design decisionmaking. In order to avoid product performance reductions due to such later-stage environmental changes, this paper discusses a reliability-based topology optimization method that can secure specified design goals even in the face of environmental factor uncertainty. This method can optimize mechanical structures with respect to two principal characteristics, namely structural stiffness and eigen-frequency. Several examples are provided to illustrate the utility of the method presented here for mechanical design engineers
Overexpression profiling reveals cellular requirements in the context of genetic backgrounds and environments
Overexpression can help life adapt to stressful environments, making an examination of overexpressed genes valuable for understanding stress tolerance mechanisms. However, a systematic study of genes whose overexpression is functionally adaptive (GOFAs) under stress has yet to be conducted. We developed a new overexpression profiling method and systematically identified GOFAs in Saccharomyces cerevisiae under stress (heat, salt, and oxidative). Our results show that adaptive overexpression compensates for deficiencies and increases fitness under stress, like calcium under salt stress. We also investigated the impact of different genetic backgrounds on GOFAs, which varied among three S. cerevisiae strains reflecting differing calcium and potassium requirements for salt stress tolerance. Our study of a knockout collection also suggested that calcium prevents mitochondrial outbursts under salt stress. Mitochondria-enhancing GOFAs were only adaptive when adequate calcium was available and non-adaptive when calcium was deficient, supporting this idea. Our findings indicate that adaptive overexpression meets the cell's needs for maximizing the organism's adaptive capacity in the given environment and genetic context. Author summaryThe study aimed to investigate how overexpression of genes can aid organisms in adapting to stress. The researchers utilized a new method to identify genes in yeast that demonstrated functional adaptability when overexpressed under stress such as heat, salt, and oxidative stress. The results indicated that overexpressing specific genes, like calcium, during salt stress could counteract deficiencies and improve the organism's ability to withstand stress. The study also examined the effect of different genetic backgrounds on these genes and discovered that the impact differed among various yeast strains. Additionally, the study revealed that calcium could play a key role in adapting to salt stress by preventing mitochondrial outbursts. These findings suggest that overexpressing certain genes can help the organism maximize its adaptability to stress in a given environment and genetic context
Diversity and potential sources of microbiota associated with snow on western portions of the Greenland ice sheet
Snow overlays the majority of the Greenland Ice Sheet (GrIS). However, there is very little information available on the microbiological assemblages that are associated with this vast and climate‐sensitive landscape. In this study, the structure and diversity of snow microbial assemblages from two regions of the western GrIS ice margin were investigated through the sequencing of small subunit ribosomal RNA genes. The origins of the microbiota were investigated by examining correlations to molecular data obtained from marine, soil, freshwater and atmospheric environments and geochemical analytes measured in the snow. Snow was found to contain a diverse assemblage of bacteria (Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria) and eukarya (Alveolata, Fungi, Stramenopiles and Chloroplastida). Phylotypes related to archaeal Thaumarchaeota and Euryarchaeota phyla were also identified. The snow microbial assemblages were more similar to communities characterized in soil than to those documented in marine ecosystems. Despite this, the chemical composition of snow samples was consistent with a marine contribution, and strong correlations existed between bacterial beta diversity and the concentration of Na+ and Cl−. These results suggest that surface snow from western regions of Greenland contains exogenous microbiota that were likely aerosolized from more distant soil sources, transported in the atmosphere and co‐precipitated with the snow
Decision analysis for transplant candidates with primary myelofibrosis in the ruxolitinib era
The recent progress with ruxolitinib treatment might improve quality-of-life as well as overall survival in patients with primary myelofibrosis (PMF). Therefore, the optimal timing of allogeneic hematopoietic cell transplantation (HCT) remains to be elucidated in the ruxolitinib era. We constructed a Markov model to simulate the 5-year clinical course of transplant candidates with PMF, and compared outcomes between immediate HCT and delayed HCT after ruxolitinib failure. Since older age was associated with an increased risk of mortality, we analyzed patients aged < 60 and ≥ 60 separately in subgroup analyses. The expected life years was consistently longer in delayed HCT after ruxolitinib failure regardless of patient age. Regarding quality-adjusted life years (QALYs), a baseline analysis showed that immediate HCT was inferior to delayed HCT after ruxolitinib failure (2.19 versus 2.26). In patients aged < 60, immediate HCT was equivalent to delayed HCT after ruxolitinib failure (2.31 versus 2.31). On the other hand, in patients aged ≥ 60, immediate HCT was inferior to delayed HCT after ruxolitinib failure (1.98 versus 2.21). A one-way sensitivity analysis showed that the utility of being alive without chronic graft-versus-host disease after immediate HCT was the most influential parameter for QALYs, and that a value higher than 0.836 could reverse the superiority of delayed HCT after ruxolitinib failure. As a result, delayed HCT after ruxolitinib failure is expected to be superior to immediate HCT, especially in patients aged ≥ 60, and is also a promising strategy even in those aged < 60
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
Synchrotron µ-XRF mapping analysis of trace elements in in-situ cultured Japanese red coral, Corallium japonicum
Precious corals belong to the family Coralliidae (Cnidaria, Octocorallia), and their axis, which consists of high magnesian calcium carbonate, has long been used in jewelry. With its low growth rate and long lifespan, precious coral is a representative taxon of the vulnerable marine ecosystem. Due to years of overfishing, coral fishery has become a controversial issue. To estimate the growth rate and clarify the uptake process of trace elements in relation to the growth of the carbonate axis, Japanese red coral (Corallium japonicum) was cultured at a depth of 135 m off Takeshima Island, Kagoshima, Japan for 98 months and analyzed by microscopic X-ray fluorescence/soft X-ray photoabsorption (µ-XRF/XAS) speciation mapping. The growth rate was estimated to be 0.37 mm/year in diameter, and 10–11 growth rings were observed in a cross section of the axis. This estimated growth-rate value is the first ever to be obtained from the in-situ culture of Japanese precious coral. The fluctuation in water temperature near the in-situ-culture site was recorded for part of the culture period and then compared with the changes in the growth ring and the distribution of trace elements in a cross section of the coral axis during the same period. When the water temperature was increasing, the growth ring was light in color, sulfur and phosphorus concentrations were low, and magnesium was high. Conversely, a dark band in the growth ring, high sulfur and phosphorus, and low magnesium concentrations were observed when the water temperature was decreasing. In a cross section of the coral axis, the distribution of sulfur and magnesium from the center to the surface corresponded, respectively, to dark and light bands in the annual growth ring. Sulfur concentration was high in the dark band and low in the light band, while magnesium was negatively correlated with sulfur