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Search Results: 1 - 10 of 543 matches for " Keiji Ogi "
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Fatigue Behavior of Open-Holed CFRP Laminates with Initially Cut Fibers  [PDF]
Sudarsono Sudarsono, Keiji Ogi
Open Journal of Composite Materials (OJCM) , 2017, DOI: 10.4236/ojcm.2017.71003
Carbon fiber-reinforced plastic (CFRP) laminates with initially cut fibers (ICFs) have good formability without large degradation of static strength; however, their fatigue behavior has not been investigated thus far. In this paper, we investigated fatigue behavior and damage progress of open-holed CFRP laminates with ICFs having interlayers. Three types of CFRP laminates were employed: a laminate without ICF fabricated using an autoclave (Continuous-A), a laminate with ICF fabricated using an autoclave (ICF-A) and a laminate with ICF fabricated using press molding (ICF-P). First, fatigue test was conducted to obtain S (maximum stress)-N (the number of cycles to failure) curves in order to reveal fatigue strength. The fatigue tests for several specimens were interrupted at three prescribed numbers of cycles to observe damage progress. It is found that the Continuous-A laminate shows little strength degradation in the S-N curve while fatigue strength in both ICF laminates is decreased by approximately 30% at N of 106. In contrast, the damage progress of the ICF-P laminate is the least among the three laminates while the delamination progress at both edges and around the hole in the Continuous-A laminate is the most prominent.
Gene therapy strategies for treating brain tumors: Retroviruses are still good candidates for therapeutic vectors  [PDF]
Toshio Yawata, Keiji Shimizu
Open Journal of Genetics (OJGen) , 2013, DOI: 10.4236/ojgen.2013.32A1002

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor in adults. In the past few decades, many efforts have been made to improve the prognosis of GBM, however, with limited success. Many gene therapy strategies for GBM have been developed and a few have progressed to clinical trials. Retroviral vectors have superior features for gene therapy in brain cancers, including tumor specificity, immunogenicity, and longer half-life. Early gene therapy trials in GBM patients based on transplantation of retrovirus-producing cells into the brain failed to prove efficacious. Adenoviral vectors, which can be prepared as high-titer virus solutions and undergo efficient transduction in tumor cells, failed in clinical trials, likely due to immunogenicity and instability of gene expression. Alternative therapeutics such as oncolytic viruses that specifically target and destroy cancer cells are currently under investigation. In addition to novel vectors, retroviral vectors are still attractive candidates for use in gene therapy against brain tumors. Since yields of properly-packaged viral particles from virus-producing cells have been very limited so far, gene therapy by direct injection of hightiter retroviral vectors into the patients’ brains was not possible. To overcome these disadvantages, a packaging cell line that yields high-titer retroviral solutions was established by our group, enabling the direct injection of massive retroviral vector stocks directly into the brain. Mouse glioma models were effectively cured with a combination of a suicide gene/ prodrug system and a highly-concentrated retrovirus solution. Preclinical assessments, including that of replication-competent retroviruses and tumorigenicity of the combination method, have confirmed the safety of the highly-concentrated retrovirus solution. Addi tional studies are needed to address the clinical utility of such combination gene therapies. Taken together, these data suggest that retroviral vectors are still good candidates for development in gene therapy applications.

Anticancer Effect in HL-60 Human Leukemia Cells and Other Helath-Beneficial Functions of Cheese  [PDF]
Shin Yasuda, Keiji Igoshi
Open Journal of Blood Diseases (OJBD) , 2013, DOI: 10.4236/ojbd.2013.33A002
Abstract: With regard to the aim of cancer prevention and/or treatment, a considerable number of basic studies have indicated that dairy and other plant-originated natural food products may possess anticancer activity. On the growth of human leukemia cells, for example, enzymatically digested skim milk or fermented milk cultured with various bacteria can exhibit differential suppressive activities. Our research team has previously revealed that highly ripened cheese was capable of demonstrating strong growth inhibition and induction of apoptotic DNA damage on HL-60 human promyelocyticleukemia cells. In this short review, the available information concerning potent anticancer effects of cheese was summarized. From the stand point of Food Science, functional implications for cancer prevention as well as multifaceted function of cheese are discussed.
Conditional Expectations for Unbounded Operator Algebras
Atsushi Inoue,Hidekazu Ogi,Mayumi Takakura
International Journal of Mathematics and Mathematical Sciences , 2007, DOI: 10.1155/2007/80152
Abstract: Two conditional expectations in unbounded operator algebras (O∗-algebras) are discussed. One is a vector conditional expectation defined by a linear map of an O∗-algebra into the Hilbert space on which the O∗-algebra acts. This has the usual properties of conditional expectations. This was defined by Gudder and Hudson. Another is an unbounded conditional expectation which is a positive linear map ℰ of an O∗-algebra ℳ onto a given O∗-subalgebra 𝒩 of ℳ. Here the domain D(ℰ) of ℰ does not equal to ℳ in general, and so such a conditional expectation is called unbounded.
Real-time Background Subtraction for Video Avatar
Hasup Lee,Yoshisuke Tateyama,Tetsuro Ogi
International Journal of Future Computer and Communication , 2013, DOI: 10.7763/ijfcc.2013.v2.117
Abstract: Background subtraction is widely used method ofdetecting moving objects in static background in computervision fields. In this paper, we present real-time backgroundsubtraction method for video avatar system or videoconferencing without blue screen. We observed the noise ofdigital camera and made a range matrix for backgroundmasking. Noise reductions were applied to both backgroundand mask using median filter blurring and open operation. Ourexperiment was performed using notebook PC and built-inwebcam. The results showed our approach is feasible toreal-time indoor environments.
Suppression of NF-κB/p65 Inhibits the Proliferation in Oral Squamous Cancer Cells  [PDF]
Naoki Anbo, Kazuhiro Ogi, Yohei Sogabe, Makoto Shimanishi, Takeshi Kaneko, Hironari Dehari, Akihiro Miyazaki, Hiroyoshi Hiratsuka
Journal of Cancer Therapy (JCT) , 2013, DOI: 10.4236/jct.2013.44100

Object: Hypoxia occurs when oxygen tension drops below normal limits, and malignant tumors often experience hypoxia, which activates the expression of genes through oxygen-sensitive transcription factors, including the hypoxiainducible factor (HIF) and the nuclear factor-κB (NF-κB). NF-κB pathway represents an attractive therapeutic target in both cancer cells and ischemic cells, which involves immune response. To investigate the expression of NF-κB target genes in oral squamous cancer carcinoma (OSCC) under hypoxia, we performed cDNA plate array analyses of 23 NF-κB-regulated genes in different cell lines. Our aim was to clarify the functions of NF-κB in OSCC under hypoxia. Results: We conducted an NF-κB reporter assay to examine NF-κB activation under hypoxia. This luciferase-based reporter assay showed that hypoxia induced NF-κB activation after 24 h of hypoxia. We also found that vascular endothelial growth factor-C (VEGF-C) of NF-κB-regulated genes was upregulated in both cell lines under hypoxia. We then tested the influence of NF-κB/p65 knockdown on these cells and NF-κB/p65 knockdown inhibited the proliferation of OSCC cells by colony assay. Conclusion: Based on these findings, we postulate that one mechanism by which hypoxic OSCC cells may involve NF-κB-mediated upregulation. Our results also indicate that the knockdown of NF-κB/p65 subunit lead to growth inhibition during hypoxia in OSCC cells. These results suggest that knockdown of NF-κB/p65 subunit could be a potential therapeutic option for patients with OSCC.

Kaposi’s Sarcoma-Associated Herpesvirus Genome Replication, Partitioning, and Maintenance in Latency
Keiji Ueda
Frontiers in Microbiology , 2012, DOI: 10.3389/fmicb.2012.00007
Abstract: Kaposi’s sarcoma-associated herpesvirus (KSHV) is thought to be an oncogenic member of the γ-herpesvirus subfamily. The virus usually establishes latency upon infection as a default infection pattern. The viral genome replicates according to the host cell cycle by recruiting the host cellular replication machinery. Among the latently expressing viral factors, LANA plays pivotal roles in viral genome replication, partitioning, and maintenance. LANA binds with two LANA-binding sites (LBS1/2) within a terminal repeat (TR) sequence and is indispensable for viral genome replication in latency. The nuclear matrix region seems to be important as a replication site, since LANA as well as cellular replication factors accumulate there and recruit the viral replication origin in latency (ori-P) by its binding activity to LBS. KSHV ori-P consists of LBS followed by a 32-bp GC-rich segment (32GC). Although it has been reported that LANA recruits cellular pre-replication complexes (pre-RC) such as origin recognition complexes (ORCs) to the ori-P through its interaction with ORCs, this mechanism does not account completely for the requirement of the 32GC. On the other hand, there are few reports about the partitioning and maintenance of the viral genome. LANA interacts with many kinds of chromosomal proteins, including Brd2/RING3, core histones, such as H2A/H2B and histone H1, and so on. The detailed molecular mechanisms by which LANA enables KSHV genome partitioning and maintenance still remain obscure. By integrating the findings reported thus far on KSHV genome replication, partitioning, and maintenance in latency, we will summarize what we know now, discuss what questions remain to be answered, and determine what needs to be done next to understand the mechanisms underlying viral replication, partitioning, and maintenance strategy.
Energy Dissipation and Fluctuation-Response in Driven Quantum Langevin Dynamics
Keiji Saito
Physics , 2008, DOI: 10.1209/0295-5075/83/50006
Abstract: Energy dissipation in a nonequilibrium steady state is studied in driven quantum Langevin systems. We study energy dissipation flow to thermal environment, and obtain a general formula for the average rate of energy dissipation using an autocorrelation function for the system variable. This leads to a general expression of the equality that connects the violation of the fluctuation-response relation to the rate of energy dissipation, the classical version of which was first studied by Harada and Sasa. We also point out that the expression depends on coupling form between system and reservoir.
On the First Order Asymptotic Theory of Quantum Estimation
Keiji Matsumoto
Physics , 2010,
Abstract: We give a rigorous treatment on the foundation of the first order asymptotic theory of quantum estimation, with tractable and reasonable regularity conditions. Different from past works, we do not use Fisher information nor MLE, and an optimal estimator is constructed based on locally unbiased estimators. Also, we treat state estimation by local operations and classical communications (LOCC), and estimation of quantum operations.
Entanglement cost and distillable entanglement of symmetric states
Keiji Matsumoto
Physics , 2007,
Abstract: We compute entanglement cost and distillable entanglement of states supported on symmetric subspace. Not only giving general formula, we apply them to the output states of optimal cloning machines. Surprisingly, under some settings, the optimal n to m clone and true m copies are the same in entanglement measures. However, they differ in the error exponent of entanglement dilution. We also presented a general theory of entanglement dilution which is applicable to any non-i.i.d sequence of states.
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