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Search Results: 1 - 10 of 6669 matches for " Shin-ichi Miyatake "
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Re-Evaluation of Attractor Neural Network Model to Explain Double Dissociation in Semantic Memory Disorder  [PDF]
Shin-ichi Asakawa
Psychology (PSYCH) , 2013, DOI: 10.4236/psych.2013.43A053

Structure of semantic memory was investigated in the way of neural network simulations in detail. In the literature, it is well-known that brain damaged patients often showed category specific disorder in various cognitive neuropsychological tasks like picture naming, categorisation, identification tasks and so on. In order to describe semantic memory disorder of brain damaged patients, the attractor neural network model originally proposed Hinton and Shallice (1991) was employed and was tried to re-evaluate the model performance. Especially, in order to answer the question about organization of semantic memory, how our semantic memories are organized, computer simulations were conducted. After the model learned data set (Tyler, Moss, Durrant-Peatfield, & Levy, 2000), units in hidden and cleanup layers were removed and observed its performances. The results showed category specificity. This model could also explain the double dissociation phenomena. In spite of the simplicity of its architecture, the attractor neural network might be considered to mimic human behavior in the meaning of semantic memory organization and its disorder. Although this model could explain various phenomenon in cognitive neuropsychology, it might become obvious that this model had one limitation to explain human behavior. As far as investigation in this study, asymmetry in category specificity between animate and inanimate objects might not be explained on this model without any additional assumptions. Therefore, further studies must be required to improve our understanding for semantic memory organisation.

IR Spectroscopic Study of Silicon Nitride Films Grown at a Low Substrate Temperature Using Very High Frequency Plasma-Enhanced Chemical Vapor Deposition  [PDF]
Shin-ichi Kobayashi
World Journal of Condensed Matter Physics (WJCMP) , 2016, DOI: 10.4236/wjcmp.2016.64027
Abstract: Hydrogenated amorphous silicon nitride (a-SiNx:H) films have been grown from a SiH4–N2 gas mixture through very high frequency (VHF) plasma-enhanced chemical vapor deposition (PECVD) at 50. The films are dense and transparent in the visible region. The peak frequency of the Si–N stretching mode in the IR absorption spectrum increases with increasing N–H bond density, which is similar to the behavior of a-SiNx:H films grown from SiH4–NH3 gas. During storage in a dry air atmosphere, the Si–O absorption increases. A large shift in the peak frequency of the Si–N stretching mode in the initial stage of oxidation, which is higher than the shift expected from the increase in the N–H bond density, is mainly caused by the change in the sum of electronegativity of nearest neighbors around the Si–N bond due to the increase in the Si–O bond density.
Key Role of Human ABC Transporter ABCG2 in Photodynamic Therapy and Photodynamic Diagnosis
Toshihisa Ishikawa,Hiroshi Nakagawa,Yuichiro Hagiya,Naosuke Nonoguchi,Shin-ichi Miyatake,Toshihiko Kuroiwa
Advances in Pharmacological Sciences , 2010, DOI: 10.1155/2010/587306
Abstract: Accumulating evidence indicates that ATP-binding cassette (ABC) transporter ABCG2 plays a key role in regulating the cellular accumulation of porphyrin derivatives in cancer cells and thereby affects the efficacy of photodynamic therapy and photodynamic diagnosis. The activity of porphyrin efflux can be affected by genetic polymorphisms in the ABCG2 gene. On the other hand, Nrf2, an NF-E2-related transcription factor, has been shown to be involved in oxidative stress-mediated induction of the ABCG2 gene. Since patients have demonstrated individual differences in their response to photodynamic therapy, transcriptional activation and/or genetic polymorphisms of the ABCG2 gene in cancer cells may affect patients' responses to photodynamic therapy. Protein kinase inhibitors, including imatinib mesylate and gefitinib, are suggested to potentially enhance the efficacy of photodynamic therapy by blocking ABCG2-mediated porphyrin efflux from cancer cells. This review article provides an overview on the role of human ABC transporter ABCG2 in photodynamic therapy and photodynamic diagnosis. 1. Introduction Photodynamic therapy (PDT) and photodynamic diagnosis are achieved by a photon-induced physicochemical reaction which is induced by excitation of photosensitizer exposed to light. In the 1960s Lipson and Baldes introduced a hematoporphyrin derivative (HpD), a product derived following by treatment of hematoporphyrin with a mixture of acetic and sulfuric acids and sodium hydroxide [1]. Their development of the hematoporphyrin derivative established the basis of today’s PDT and photodynamic diagnosis [2–6]. PDT utilizes porphyrin derivatives to generate singlet oxygen (1O2) and other reactive oxygen species (ROS) that are potent in killing cancer cell in vivo [7]. The modern era of PDT was founded in the 1970s with the pioneering work of Dougherty and his coworkers who purified HpD later called Photofrin. In 1978, Dougherty et al. had carried out the first human trials of Photofrin on women with advanced breast cancer [8]. Photofrin is still the most widely used photosensitizer in clinical PDT. Recent studies of modern PDT began just two decades ago; therefore there are still unsolved problems. Nevertheless, PDT has many applications in a wide range of fields of both preclinical and clinical sciences. In recent years, remarkable advances were made in photodynamic diagnosis technology that makes it easier to reliably achieve complete excision of malignant gliomas [9–11] and meningiomas [12]. The extent of tumor resection that should be undertaken in patients with
On the Concavity of the Consumption Function with a Quadratic Utility under Liquidity Constraints  [PDF]
Shin-Ichi Nishiyama, Ryo Kato
Theoretical Economics Letters (TEL) , 2012, DOI: 10.4236/tel.2012.25104
Abstract: This paper demonstrates the concavity of the consumption function of infinitely living households under liquidity constraints who are not prudent—i.e. with a quadratic utility. The concavity of the consumption function is closely related to the 3-convexity of the value function.

Changes in Attitudes toward Lumbar Spinal Stenosis Treatment  [PDF]
Shin-ichi Konno, Miho Sekiguchi
Open Journal of Orthopedics (OJO) , 2014, DOI: 10.4236/ojo.2014.46027
Abstract: As the environment surrounding healthcare continues to evolve, there is a need to revise outcome assessment criteria. A shift is being demanded in diagnosis and treatment outcome assessment practices from objective to subjective assessment and from evaluation by doctors to assessment that is based on the patient’s own perspective. Therefore, lumbar diseases must now be assessed from multiple perspectives. Some major indices for evaluation are pain and numbness, functional status, general health status, disability, and patient satisfaction. An effective assessment method for lumbar spinal stenos is that examines symptoms, quality of life, and healthcare economics as key assessment factor is reviewed.
Synthesis and Properties of Polyurethane Elastomers Containing Sucrose as a Cross-Linker  [PDF]
Kazunori Kizuka, Shin-Ichi Inoue
Open Journal of Organic Polymer Materials (OJOPM) , 2015, DOI: 10.4236/ojopm.2015.54011
Abstract: Polyaddition using isocyanate and polyol forms polyurethane elastomer (PUE). However, this method has rarely been applied to the construction of PUEs containing sucrose. Hence, the introduction of sucrose (disaccharide) as a cross-linker via polyaddition remains a challenging subject in polymer chemistry. Here, we report the synthesis of PUEs using an aromatic isocyanate (4,4’-diphenylmethane diisocyanate), polyols including a polyether polyol (polytetramethylene glycol) and two polyester polyols (polycaprolactone and polycarbonate diols), and sucrose as a crosslinker by a one-shot method. The PUEs containing sucrose were successfully produced. The use of sucrose was essential to obtain the desired PUEs containing sucrose units in the main chain.
Synthesis and Properties of Chiral Polyurethane Elastomers Using Tartaric Acids  [PDF]
Kazunori Kizuka, Shin-Ichi Inoue
Open Journal of Organic Polymer Materials (OJOPM) , 2016, DOI: 10.4236/ojopm.2016.61005

The polyaddition of isocyanate and polyol to form polyurethane elastomers has rarely been applied to the construction of chiral polyurethane elastomers. Hence, the introduction of chiral units via polyaddition remains a challenging subject in polymer chemistry. In this study, the synthesis of chiral polyurethane elastomers using an aromatic isocyanate, polyols (polyether and polyester polyols), and L(+)-, D(−)-, or meso-tartaric acid by a one-shot method is investigated. The polymers are characterized using FTIR and NMR spectroscopy, and their thermal properties are investigated by TGA, DMA, and DSC analyses. The optical activities of the polymers are confirmed by rotation. The use of chiral tartaric acids is essential to obtain the desired chiral polyurethane elastomers.

Synthesis and Properties of Polyurethane Elastomers with Trehalose Units  [PDF]
Kazunori Kizuka, Shin-Ichi Inoue
Open Journal of Organic Polymer Materials (OJOPM) , 2016, DOI: 10.4236/ojopm.2016.62007
Abstract: In recent years, sugar-derived polymer materials have been actively investigated. In research of polyurethane (PU), sugar has been used as a raw material because it has properties similar to polyol. However, the elastic property of the obtained PU is substantially lost. Hence, the introduction of a sugar unit to PU while maintaining the elastic property remains a challenge in polymer chemistry. Here, we report the synthesis of a polyurethane elastomer (PUE) with a trehalose unit using raw materials such as an aromatic diisocyanate (4,4’-diphenylmethane diisocyanate), polyols including a polyether polyol (polytetramethylene glycol), two polyester polyols (polycaprolactone and polycarbonate diol), and trehalose. Novel PUEs with trehalose units are synthesized by a one-shot method. Trehalose, which has non-reducing properties, is used as sugar. The use of trehalose, which has been scarcely applied to PUE, is essential to obtain the desired PUEs with sugar units.
Nutrients Modulate T1r2 Transcript Levels in MIN 6 and Primary Cultured Taste Buds Cells under High Glucose Condition  [PDF]
Shin-ichi Nakmura, Tetsuya Ookura
Food and Nutrition Sciences (FNS) , 2016, DOI: 10.4236/fns.2016.74033
Abstract: The sweet taste receptors comprised of T1r2 and T1r3, sense glucose concentrations in the gastrointestine. While hyperglycemia was reported to decrease the T1R2 and T1R3 tanscript levels in healthy subjects, no change was observed in type 2 diabetes patients. We investigated which glucose level and nutrients affect those transcript levels in MIN 6 and primary cultured taste buds cells using quantitative Reverse Trancription Polymerase Chain Reaction. High glucose diminished T1r2 transcript levels in MIN 6 and primary cultured taste buds cells. Resveratrol and its analogue augmented transcript levels of T1r1 and T1r2 above normal levels in MIN 6 cells in the medium with 25 mM glucose. Adenine, but not guanine, augmented T1r2 transcript levels of MIN 6 cells in the medium with 25 mM glucose. These results imply that nutrients in meals could affect sweet taste sensitivity by modulating T1r2 transcript levels in response to blood glucose levels.
Influence of Diisocyanate on Polyurethane Elastomers Which Crosslinked by β-Cyclodextrin  [PDF]
An Xie, Ming Zhang, Shin-Ichi Inoue
Open Journal of Organic Polymer Materials (OJOPM) , 2016, DOI: 10.4236/ojopm.2016.63010
Abstract: A series of polyurethane elastomers (PUEs) were synthesized by using β-cyclodextrin (β-CD) as cross-linker from aliphatic, alicyclic, aromatic diisocyanates, and polyol. The PUEs were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA), swelling test, hardness test and tensile test. The influence of diisocyanate on microphase separation and properties of PUEs was evaluated.
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