137 research outputs found

    Shear Strength of Reinforced Concrete Shear Walls under Eccentric Tensile Axial Force

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    Six reinforced concrete shear wall models were built and tested to investigate effects of cyclic lateral loading and an eccentric tensile axial force on their shear strength behavior. The following are confirmed from this test result. When the elongation at the bottom of the boundary column on the compression side for a lateral force is small, the shear strength of shear walls subjected to a tensile axial force at the boundary column can be evaluated by conventional shear strenght equations, regardless of cycilc lateral loading and the eccentric tensile axial force. However when this elongation of the boundary column increases, the test maximum value is much lower than the value calculated from conventional equations

    On the transient response of serpentine (antigorite) gouge to stepwise changes in slip velocity under high-temperature conditions

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    Shear-sliding tests were conducted on serpentine (antigorite) gouge to understand the rheology of serpentine-bearing faults. The experiments were carried out using a constant confining pressure (100 MPa), a constant pore water pressure (30 MPa), and a range of temperatures (from room temperature to 600 degrees C). The transient response in frictional behavior following stepwise changes in the slip velocity were documented at each temperature. Slip rates varied between 0.0115 and 11.5 mu m/s. Both the general level of frictional strength and the transient responses changed drastically at around 450 degrees C. As the temperature increased from 400 degrees C to 450 degrees C, the strength of antigorite rose sharply. The transient response also indicated a change in the mode of deformation from flow-type behavior at temperatures below 400 degrees C to frictional behavior (stick-slip) at temperatures above 450 degrees C-500 degrees C. Although only a limited volume of serpentine was involved in the dehydration reaction, X-ray diffraction analyses and scanning electron microscopy observations showed that forsterite had nucleated in the experimental products at the higher temperatures that were associated with frictional behavior. Submicron-sized, streaky forsterite masses in shear-localized zones may be evidence of shear-induced dehydration that caused strengthening and embrittlement of the gouge. Although antigorite rheology is complicated, the subsequent change in friction coefficient per order-of-magnitude change in sliding velocity increased with both increasing temperature and decreasing velocity, implying that a possible flow mechanism of intragranular deformation became activated

    In Vivo

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    In vivo real-time visualization of the process of angiogenesis in secondary tumors in the same living animals presents a major challenge in metastasis research. We developed a technique for intravital imaging of colorectal liver metastasis development in live mice using two-photon laser scanning microscopy (TPLSM). We also developed time-series TPLSM in which intravital TPLSM procedures were performed several times over periods of days to months. Red fluorescent protein-expressing colorectal cancer cells were inoculated into the spleens of green fluorescent protein-expressing mice. First- and second-round intravital TPLSM allowed visualization of viable cancer cells (red) in hepatic sinusoids or the space of Disse. Third-round intravital TPLSM demonstrated liver metastatic colonies consisting of viable cancer cells and surrounding stroma with tumor vessels (green). In vivo time-course imaging of tumor angiogenesis in the same living mice using time-series TPLSM could be an ideal tool for antiangiogenic drug evaluation, reducing the effects of interindividual variation

    MicroRNAs in Human Malignant Gliomas

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    MicroRNA (miRNA) is a new class of small noncoding RNA molecules that regulate a wide spectrum of gene expression in a posttranscriptional manner. MiRNAs play crucial roles in tumorigenesis, angiogenesis, invasion, and apoptosis for various types of tumor. Recent studies have identified dysregulation of specific miRNAs in malignant gliomas. Global expression profiling of miRNAs has revealed several miRNAs clinically implicated in human glioblastomas. Some miRNAs are clearly associated with clinical outcome and chemo- and radio-therapy resistance in these tumors. Furthermore, miRNAs also regulate specific signaling pathways, including the critical core pathways in glioblastoma. As a result, miRNAs have the potential to affect the responses to molecular-targeted therapies. More recent studies have revealed that miRNAs might be associated with cancer stem cell properties, affecting tumor maintenance and progression. Recent investigation have revealed that miRNAs are not only biological markers with diagnostic implications, but also one of the most promising treatment targets in human glioblastoma. Herein, we summarized the novel insights of miRNAs into human malignant gliomas

    A multi-ethnic meta-analysis identifies novel genes, including ACSL5, associated with amyotrophic lateral sclerosis

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    Amyotrophic lateral sclerosis (ALS) is a devastating progressive motor neuron disease that affects people of all ethnicities. Approximately 90% of ALS cases are sporadic and thought to have multifactorial pathogenesis. To understand the genetics of sporadic ALS, we conducted a genome-wide association study using 1,173 sporadic ALS cases and 8,925 controls in a Japanese population. A combined meta-analysis of our Japanese cohort with individuals of European ancestry revealed a significant association at the ACSL5 locus (top SNP p = 2.97 × 10−8). We validated the association with ACSL5 in a replication study with a Chinese population and an independent Japanese population (1941 ALS cases, 3821 controls; top SNP p = 1.82 × 10−4). In the combined meta-analysis, the intronic ACSL5 SNP rs3736947 showed the strongest association (p = 7.81 × 10−11). Using a gene-based analysis of the full multi-ethnic dataset, we uncovered additional genes significantly associated with ALS: ERGIC1, RAPGEF5, FNBP1, and ATXN3. These results advance our understanding of the genetic basis of sporadic ALS

    Déclaration sur l’approche par l’archéologie sociale du changement climatique

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    Manifiesto sobre Arqueología Social del Cambio Climático aprobado en la Cumbre SACC celebrada en Kiel. Aprobado y firmado el 6 de septiembre de 2021.[ES] El SACC es un grupo independiente, constituido en Kiel, de investigadores e investigadoras que trabajan sobre cambio climático. El objetivo de SACC es reunir científicos y científicas internacionales y representantes de importantes organizaciones internacionales de las áreas de arqueología, paleoecología y gestión del patrimonio para con el fin de discutir y evaluar la contribución de la investigación arqueológica y paleo-ecológica para comprender la interrelación entre el cambio social, el cultural, el ecológico y el climático. Pretendemos resaltar cómo la arqueología, a través del estudio de la conducta adaptativa en el pasado, es capaz de reforzar tanto la resiliencia socio-ecológica de nuestras sociedades, como su capacidad adaptativa ante el actual cambio climático. Además, pretendemos contribuir a la comprensión del impacto del cambio climático en los yacimientos y sitios arqueológicos y patrimoniales, así como en los paisajes culturales, los museos, las colecciones y archivos patrimoniales. SACC celebrará cumbres cada dos años y emitirá una declaración o manifiesto al término de cada una de ellas. S ACC está organizada por un comité interino presidido por las personas convocantes del SACC 1.[EN] SACC is an independent group of researchers working on climate change in the past constituted in Kiel. The aim of SACC is to bring together international scientists and representatives of important international organisations in the fields of archaeology, paleoecology and heritage management to discuss and evaluate the contribution of archaeological and paleo-ecological research to understand the link between social, cultural, ecological and climatic change; and to highlight how archaeology, through the study of past adaptive behaviour, is able to enhance socio-ecological resilience of societies as well as their adaptive capacity to current climate change; furthermore, to contribute to the understanding of the impact of climate change on archaeological and heritage sites as well as on cultural landscapes, museums, collections, and archives. SACC will hold its summit every second year with a declaration at the end of each summit. SACC is organized by a steering committee chaired by the SACC 1 organisers.[FR] Le SACC est un groupe indépendant de chercheurs travaillant sur le changement climatique dans le passé, qui s’est formé à Kiel. L’objectif du S ACC est de réunir des scientifiques internationaux et des représentants d’organisations internationales importantes dans les domaines de l’archéologie, de la paléoécologie et de la gestion du patrimoine. Il a pour objectif de discuter et d’évaluer la contribution de la recherche archéologique et paléo-écologique à la compréhension du lien entre les changements sociaux, culturels, écologiques et climatiques et de souligner comment l’archéologie, par l’étude du comportement adaptatif du passé, est capable d’améliorer la résilience socioécologique des sociétés ainsi que leur capacité d’adaptation au changement climatique actuel. En outre, il contribue à la compréhension de l’impact du changement climatique sur les sites archéologiques et patrimoniaux ainsi que sur les paysages culturels, les musées, les collections et les archives. Le SACC tiendra son conseil tous les deux ans avec une déclaration à la fin de chaque conseil. Il est organisé par un comité de pilotage présidé par les organisateurs de SACC 1.Peer reviewe

    Blockade of Gap Junction Hemichannel Suppresses Disease Progression in Mouse Models of Amyotrophic Lateral Sclerosis and Alzheimer's Disease

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    Glutamate released by activated microglia induces excitotoxic neuronal death, which likely contributes to non-cell autonomous neuronal death in neurodegenerative diseases, including amyotrophic lateral sclerosis and Alzheimer's disease. Although both blockade of glutamate receptors and inhibition of microglial activation are the therapeutic candidates for these neurodegenerative diseases, glutamate receptor blockers also perturbed physiological and essential glutamate signals, and inhibitors of microglial activation suppressed both neurotoxic/neuroprotective roles of microglia and hardly affected disease progression. We previously demonstrated that activated microglia release a large amount of glutamate specifically through gap junction hemichannel. Hence, blockade of gap junction hemichannel may be potentially beneficial in treatment of neurodegenerative diseases.In this study, we generated a novel blood-brain barrier permeable gap junction hemichannel blocker based on glycyrrhetinic acid. We found that pharmacologic blockade of gap junction hemichannel inhibited excessive glutamate release from activated microglia in vitro and in vivo without producing notable toxicity. Blocking gap junction hemichannel significantly suppressed neuronal loss of the spinal cord and extended survival in transgenic mice carrying human superoxide dismutase 1 with G93A or G37R mutation as an amyotrophic lateral sclerosis mouse model. Moreover, blockade of gap junction hemichannel also significantly improved memory impairments without altering amyloid β deposition in double transgenic mice expressing human amyloid precursor protein with K595N and M596L mutations and presenilin 1 with A264E mutation as an Alzheimer's disease mouse model.Our results suggest that gap junction hemichannel blockers may represent a new therapeutic strategy to target neurotoxic microglia specifically and prevent microglia-mediated neuronal death in various neurodegenerative diseases
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