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Search Results: 1 - 10 of 1303 matches for " Mika Nagai "
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Activation and detection of HTLV-I Tax-specific CTLs by Epitope expressing Single-Chain Trimers of MHC Class I in a rat model
Takashi Ohashi, Mika Nagai, Hiroyuki Okada, Ryo Takayanagi, Hisatoshi Shida
Retrovirology , 2008, DOI: 10.1186/1742-4690-5-90
Abstract: We have established expression vectors which encode SCTs of rat MHC-I (RT1.Al) with Tax180-188 peptide. Human cell lines transfected with the established expression vectors were able to induce IFN-γ and TNF-α production by a Tax180-188-specific CTL line, 4O1/C8. We have further fused the C-terminus of SCTs to EGFP and established cells expressing SCT-EGFP fusion protein on the surface. By co-cultivating the cells with 4O1/C8, we have confirmed that the epitope-specific CTLs acquired SCT-EGFP fusion proteins and that these EGFP-possessed CTLs were detectable by flow cytometric analysis.We have generated a SCT of rat MHC-I linked to Tax epitope peptide, which can be applicable for the induction of Tax-specific CTLs in rat model systems of HTLV-I infection. We have also established a detection system of Tax-specific CTLs by using cells expressing SCTs fused with EGFP. These systems will be useful tools in understanding the role of HTLV-I specific CTLs in HTLV-I pathogenesis.Human T-cell leukemia virus type I (HTLV-I) is etiologically linked to adult T-cell leukemia (ATL) [1,2], a chronic progressive neurological disorder termed HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) [3,4], and various other human diseases [5-8]. ATL is a malignant lymphoproliferative disease affecting a subgroup of middle-aged HTLV-I carriers characterized by the presence of mature T cell phenotype [9]. HTLV-I genome contains a unique 3' region, designated as pX, which encodes the viral transactivator protein, Tax [10]. Because of its broad transactivation capabilities [11], it is speculated that Tax plays a central role in HTLV-I associated immortalization and transformation of T cells, which may lead to the development of ATL.Tax is also known as a major target protein recognized by cytotoxic T lymphocytes (CTL) of HTLV-I carriers [12]. It has been reported that the levels of HTLV-I-specific CTL are quite diverse among HTLV-I carriers and that ATL patients have impaired l
Resistance coefficient during ice slurry flow through pipe sudden constriction
?. Mika
Archives of Foundry Engineering , 2010,
Abstract: Due to the adverse environmental effects of some commonly-used refrigerants, efforts are still underway to find new cooling mediumsthat would be safer to the ozone layer and would not increase the greenhouse effect. Ice slurry as a new ecological coolant suits theprocesses requiring the preservation of constant and equal temperature in the cooling process of the full section of the cooled solid. Thanks to that, ice slurry can find a wide potential application in such branches of industry, as heat treatment, materials engineering, or foundry. In this paper, flow systems which are commonly used in fittings elements such as diameter’s reductions in ice slurry pipelines, are experimentally investigated. In the study reported in this paper, the consideration was given to the specific features of the slurry flow in which the flow qualities depend mainly on the volume fraction of solid particles. The results of the experimental studies on the flow resistance, presented herein, enabled to determine the resistance coefficient during the ice slurry flow through the pipe sudden constriction. The volume fraction of solid particles in the slurry ranged from 5 to 30%. The recommended and non-recommended range of the Reynolds number for the ice slurry flow through the pipe sudden constriction were presented in this paper. The experimental studies were conducted on a few variants of the most common reductions of copper pipes. Further studies on the determination of the resistance coefficient in the remaining fittings elements of the pipeline were recommended in the paper as well as the further theoretical studies intended to determine the theoretical relations to calculate the resistance coefficient in all the fittings elements in the pipeline (on the basis of the experimental studies) and to elaborate the calculation pattern of the entire ice slurry system.
Synergistic effect of human CycT1 and CRM1 on HIV-1 propagation in rat T cells and macrophages
Hiroyuki Okada, Xianfeng Zhang, Ismael Ben Fofana, Mika Nagai, Hajime Suzuki, Takashi Ohashi, Hisatoshi Shida
Retrovirology , 2009, DOI: 10.1186/1742-4690-6-43
Abstract: Expression of hCycT1 augmented Gag production 20–50 fold in rat T cells, but had little effect in macrophages. Expression of hCRM1 enhanced Gag production 10–15 fold in macrophages, but only marginally in T cells. Expression of both factors synergistically enhanced p24 production to levels approximately 10–40% of those detected in human cells. R5 viruses produced in rat T cells and macrophages were fully infectious.The expression of both hCycT1 and hCRM1 appears to be fundamental to developing a rat model that supports robust propagation of HIV-1.A small-animal model of HIV-1 infection is needed for development of prophylactic vaccines and more efficient antiviral therapies. Current animal models of HIV infection, including non-human primates [1-4] and severe combined immunodeficiency (SCID) mice transplanted with fetal human cells [5,6], have made significant contributions to our understanding of lentiviral pathogenesis and to the development of vaccines and therapeutic agents. However, these models have shortcomings, such as their limited availability and high cost, their permissivity restricted to related retroviruses of nonhuman primates, as well as the absence or insufficient induction of an immune response against HIV-1. Therefore, a better small-animal model is needed.Rodents may be useful models if they can be infected with HIV-1. Because they are established experimental animals, inbred strains are available, and genetic manipulations can be performed. However, a fully permissive model has not been developed yet because of several inherent blocks to HIV-1 replication in rodent cells. One major block to HIV-1 replication is at the level of viral entry into the cell; this may be overcome by introducing human CD4 (hCD4) and CCR5 (hCCR5) [7,8]. Indeed, transgenic (Tg) rats expressing these receptors support some HIV-1 replication, albeit poorly [8], whereas Tg mice expressing hCD4 and hCCR5 do not support any HIV replication [9]. These results suggest that rats
Characterization of Acid-Soluble Collagen from Skins of Surf Smelt (Hypomesus pretiosus japonicus Brevoort)  [PDF]
Takeshi Nagai
Food and Nutrition Sciences (FNS) , 2010, DOI: 10.4236/fns.2010.12010
Abstract: Acid-soluble collagen was extracted from the skins of surf smelt and characterized. The yield of collagen was high about 24.0% on a dry weight basis. By SDS-polyacrylamide gel electrophoresis and CM-Toyopearl 650 M column chromatography, this collagen is a heterotrimer with a chain composition of α1α2α3. The denaturation temperature was 32.5℃, about 4.5℃ lower than that from porcine skin. Attenuated total reflectance-fourier transform infrared analysis showed that the percentage of secondary structural components in this collagen were 11% α-helix, 34% β-sheet, 19% β-turn, and 21% others. It suggests that the triple helical structure is present in the acid-soluble collagen from the skins of the surf smelt in comparison to that from the skin of porcine.
Modified Cp Criterion for Optimizing Ridge and Smooth Parameters in the MGR Estimator for the Nonparametric GMANOVA Model  [PDF]
Isamu Nagai
Open Journal of Statistics (OJS) , 2011, DOI: 10.4236/ojs.2011.11001
Abstract: Longitudinal trends of observations can be estimated using the generalized multivariate analysis of variance (GMANOVA) model proposed by [10]. In the present paper, we consider estimating the trends nonparametrically using known basis functions. Then, as in nonparametric regression, an overfitting problem occurs. [13] showed that the GMANOVA model is equivalent to the varying coefficient model with non-longitudinal covariates. Hence, as in the case of the ordinary linear regression model, when the number of covariates becomes large, the estimator of the varying coefficient becomes unstable. In the present paper, we avoid the overfitting problem and the instability problem by applying the concept behind penalized smoothing spline regression and multivariate generalized ridge regression. In addition, we propose two criteria to optimize hyper parameters, namely, a smoothing parameter and ridge parameters. Finally, we compare the ordinary least square estimator and the new estimator.
Pitfalls and Remedies in DEA Applications: How to Handle an Occurrence of Zero in Multipliers by Strong Complementary Slackness Conditions  [PDF]
Toshiyuki Sueyoshi, Mika Goto
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.55A005
Abstract: This study discusses a guideline on a proper use of Data Envelopment Analysis (DEA) that has been widely used for performance analysis in public and private sectors. The use of DEA is equipped with Strong Complementary Slackness Conditions (SCSCs) in this study, but an application of DEA/SCSCs depends upon its careful use, as summarized in the guideline. The guideline consists of the five suggestions. First, a data set used in the DEA applications should not have a ratio variable (e.g., financial ratios) in an input(s) and/or an output(s). Second, radial DEA models under variable and constant Returns to Scale (RTS) need a special treatment on zero in a data set. Third, the DEA evaluation needs to drop an outlier. Fourth, an imprecise number (e.g., 1/3) may suffer from a round-off error because DEA needs to specify it in a precise expression to operate a computer code. Finally, when a large input or output variable may dominate other variables in DEA computation, it is necessary to normalize the data set or simply to divide each observation by its average. Such a simple treatment produces more reliable DEA results than the one without any data adjustment. This study also discusses how to handle an occurrence of zero in DEA multipliers by applying SCSCs. The DEA/SCSCs can serve for a multiplier restriction approach without any prior information. Thus, the propesed DEA/SCSCs can provide more reliable results than a straight use of DEA.
Uncovering Executive Prioritization: Evaluating Customer Value Propositions with the Pairwise Comparison Method  [PDF]
Mika Yrj?l?
Journal of Service Science and Management (JSSM) , 2015, DOI: 10.4236/jssm.2015.81001
Abstract: Creating customer value is a managerial priority. The role of executives is to choose what type(s) of customer value to propose to customers in the form of a customer value proposition (CVP). The decision is a complex one, because executives have to compare and weigh concrete, measurable elements alongside abstract, subjective ones. The purpose of this paper is to identify themes relating to the use of the pairwise comparison method (PCM) as a tool for prioritizing customer value dimensions from the perspective of retail executives. As a result, this paper first highlights examples of PCM outputs, and second, identifies four themes that capture executive views of the PCM.
Mitochondrial Respiration Is Associated with Alloxan-Induced Mitochondrial Permeability Transition  [PDF]
Koichi Sakurai, Mika Itoh
Journal of Biophysical Chemistry (JBPC) , 2016, DOI: 10.4236/jbpc.2016.74008
Abstract: We previously showed that increased mitochondrial inner membrane permeability which is known as mitochondrial permeability transition (MPT) is triggered by adding succinate in the presence of the diabetogenic agent alloxan. Here, our aim was to investigate whether mitochondrial respiration is associated with alloxan-induced MPT. After mitochondria isolated from rat liver were incubated with alloxan at 37°C for 5 min, the addition of succinate immediately triggered the MPT in the presence of rotenone. However, little or no induction occurred at incubation temperatures below 25°C. Malate/glutamate also triggered MPT by alloxan in the absence of rotenone. In mitochondrial suspensions containing alloxan, succinate accelerated oxygen consumption that was completely inhibited by cyanide. These results suggest that mitochondrial respiration is associated with the alloxan-induced MPT. Alloxan radical production was investigated using ESR spectroscopy. Mitochondria incubated with succinate and alloxan elicited low signal intensity (radical formation) that increased significantly in the presence of cyanide. When the incubation of alloxan with mitochondria after the addition of succinate, a little intensity of the signal was observed, but it was remarkably increased after the addition of cyanide. Ubiquinone analogues inhibited the MPT induction. These results suggest that the initiation of MPT is associated with alloxan redox cycling via an electron transfer process at a quinone-binding site in respiratory mitochondria.
Vertebral Bone Drilling (Puncture) Attenuates the Intractable Pain Due to Vertebral Fractures without Collapse  [PDF]
Koichi Ota, Hirosi Nagai
Open Journal of Anesthesiology (OJAnes) , 2016, DOI: 10.4236/ojanes.2016.64012
Abstract: Purpose: Osteoporotic vertebral fractures with no sign of vertebral collapse on initial radiographs, which is so-called occult vertebral fractures (VFs), exist. Occult VFs have a high rate of missed diagnosis, and the treatment of these fractures has rarely been discussed in the literature. We evaluated the effects of vertebral bone drilling for the pain due to occults VFs. Materials and Methods: Eighteen patients with painful osteoporotic occult VFs underwent the vertebral bone drilling. We evaluated the clinical outcome by comparing numerical rating scale (NRS) and activity of daily life (ADL) values between before and after the vertebral bone drilling. Comparisons were made by using Wilcoxon signed rank test. Results: The mean baseline NRS and ADL score, and the mean NRS and ALD score after the bone drilling were 8.4 ± 0.8, 2.2 ± 0.6, 2.4 ± 1.0, 4.6 ± 0.5, respectively. Among the patients, we detected significant improvements in NRS pain score and ADL score after the drilling compared with baseline score (p < 0.0002). Conclusion: Vertebral bone drilling at the site of painful vertebral compression fractures alleviated the intractable pain due to osteoporotic occult VFs.
An Overview of Folding Techniques in Architecture Design  [PDF]
Tao Shen, Yukari Nagai
World Journal of Engineering and Technology (WJET) , 2017, DOI: 10.4236/wjet.2017.53B002
Abstract:
In recent years, folding techniques are widely used by many architects to make 3D forms from 2D sheets as an inspiration for their design, which enables simpler and more intuitive solutions for architectural realization. This research provides an overview of using folding techniques in architecture design, with an emphasis on their new applications. In this overview, we classify folding techniques as computation geometry folding techniques and manual folding techniques. Finally, we provide recommendations for future development.
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