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Search Results: 1 - 10 of 1169 matches for " Naoto Shimada "
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Evaluation of the Method Based on Restriction Fragment Length Polymorphism Analysis as Simple Analysis Method of Lactic Acid Bacteria in Foods  [PDF]
Kunimasa Matsumoto, Kouya Shimada, Naoto Horinishi, Katsuji Watanabe
Food and Nutrition Sciences (FNS) , 2016, DOI: 10.4236/fns.2016.73018
Abstract: Lactic acid bacteria have not only been used to produce various kinds of fermented food, but also used as probiotic products. As lactic acid bacterial group was consisted from diverse genera, a simple inspection method by which numbers and contained microorganisms could be automatically analyzed without any preliminary information was required to use them more effectively. In this manuscript, lactic acid bacterial groups in commercial products of kimuchi, komekouji-miso, and yoghurt were identified and enumerated by our newly developed method [1]-[3], to evaluate whether the method could be used as an inspection method of various food samples. In kimuchi, numerically dominant bacteria were Lactobacillus sakei, and L. casei (1.4 × 104 MPN g-1) and Leuconostoc spp. (l.4 × 104 MPN). In kouji-miso, numerically dominant bacteria was Bacillus spp. (3 × 103 MPN), which mainly included B. subtilis group and B. cereus group. Lactic acid bacteria such as Lactobacillus spp., or Lactococcus spp., included in the komekouji-miso, could be enumerated after 3 days incubation (1.24 × 104 MPN), but not detected after 7 days incubation. In yoghurt A and C, Lactococcus lactis was detected as numerically dominant lactic acid bacteria (3.0 × 105 MPN). In yoghurt B, Lactobacillus spp., or Lactococcus spp., was detected not only by a culturebased method but also by an unculture-based method, although there was a difference between the both estimated numbers. The present results suggested that the method might become useful as a simple inspection method of food microorganisms, because time and labor of the analysis could be reduced by using an unculture-based method and MCE-202 MultiNA. In this study, Bifidobacteriium spp. was not detected in B and C yoghurt, in spite of indicating their existence, and numbers of lactic acid bacteria were lower than the level of the daily product regulation, because 16S rDNA of Bifidobacteriium spp. might not be amplified by the used PCR condition. The PCR condition must be changed so as to amplify Bifidobacterium spp., before the method will be used as an inspection method for lactic acid bacteria.
Analyzing the House Fly's Exploratory Behavior with Autoregression Methods
Hisanao Takahashi,Naoto Horibe,Masakazu Shimada,Takashi Ikegami
Physics , 2007, DOI: 10.1143/JPSJ.77.084802
Abstract: This paper presents a detailed characterization of the trajectory of a single housefly with free range of a square cage. The trajectory of the fly was recorded and transformed into a time series, which was fully analyzed using an autoregressive model, which describes a stationary time series by a linear regression of prior state values with the white noise. The main discovery was that the fly switched styles of motion from a low dimensional regular pattern to a higher dimensional disordered pattern. This discovered exploratory behavior is, irrespective of the presence of food, characterized by anomalous diffusion.
Insulin-Producing Cells Regulate the Sexual Receptivity through the Painless TRP Channel in Drosophila Virgin Females
Takaomi Sakai, Kazuki Watanabe, Hirono Ohashi, Shoma Sato, Show Inami, Naoto Shimada, Toshihiro Kitamoto
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088175
Abstract: In a variety of animal species, females hold a leading position in evaluating potential mating partners. The decision of virgin females to accept or reject a courting male is one of the most critical steps for mating success. In the fruitfly Drosophila melanogaster, however, the molecular and neuronal mechanisms underlying female receptivity are still poorly understood, particularly for virgin females. The Drosophila painless (pain) gene encodes a transient receptor potential (TRP) ion channel. We previously demonstrated that mutations in pain significantly enhance the sexual receptivity of virgin females and that pain expression in painGAL4-positive neurons is necessary and sufficient for pain-mediated regulation of the virgin receptivity. Among the painGAL4-positive neurons in the adult female brain, here we have found that insulin-producing cells (IPCs), a neuronal subset in the pars intercerebralis, are essential in virgin females for the regulation of sexual receptivity through Pain TRP channels. IPC-specific knockdown of pain expression or IPC ablation strongly enhanced female sexual receptivity as was observed in pain mutant females. When pain expression or neuronal activity was conditionally suppressed in adult IPCs, female sexual receptivity was similarly enhanced. Furthermore, both pain mutations and the conditional knockdown of pain expression in IPCs depressed female rejection behaviors toward courting males. Taken together, our results indicate that the Pain TRP channel in IPCs plays an important role in controlling the sexual receptivity of Drosophila virgin females by positively regulating female rejection behaviors during courtship.
A 100% Water Mobile Phase HPLC-PDA Analysis of Meamine and Related Analogues  [PDF]
Naoto Furusawa
American Journal of Analytical Chemistry (AJAC) , 2012, DOI: 10.4236/ajac.2012.34040
Abstract: This paper describes a reserved-phase high performance liquid chromatographic method for detecting melamine (MEL) and related analogues, cyanuric acid (CYA), ammeline (AML), and ammelide (AMD), using a 100% water mobile phase. Chromatographic separation was performed an Inertsil? ODS-4 (250 × 4.6 mm, 5 μm) with a water mobile phase and a photodiode-array detector. The monitoring wavelength was adjusted to 210 nm which represents an average maximum for all the analytes. The total run time was < 8 min. The method shows high stability, significant linearity and satisfactory sensitivity. The detection limits were established in the range 23 - 46 ng.mL–1. An inexpensive and harmless method for the simultaneous detection of MEL, CYA, AML, and AMD was developed and may be further applied to the quantification in foods.
Organic Solvent-Free and Simple Method for Determining Cyromazine and Its Metabolite, Melamine, in Cow’s Milk  [PDF]
Naoto Furusawa
Journal of Analytical Sciences, Methods and Instrumentation (JASMI) , 2012, DOI: 10.4236/jasmi.2012.22013
Abstract: This paper described an organic solvent-free, rapid, simple, and space-saving method of sample preparation followed by HPLC coupled photo-diode array (PDA) detector for simultaneous quantification of cyromazine (CYR) and its decy-cropropylated metabolite, melamine (MEL), in milk. The HPLC-PDA was performed on an Inertsil? HILIC column with an isocratic aqueous mobile phase. Analytes were extracted from the sample using water, and purified by Mono-Spin?-C18, a centrifugal monolithic silica spin mini-columns, and quantified within 20 min. The method, performed under 100% aqueous conditions, obtained average recoveries for CYR and MEL in the range of 93.2% - 99.1% with relative standard deviations ≤ 2.8%. The quantitation limits were 8.5 ng/mL for CYR and 10 ng/mL for MEL, respectively. No organic solvents were used at any stage of the analysis.
Discrete Differential Geometry of n-Simplices and Protein Structure Analysis  [PDF]
Naoto Morikawa
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.516237
Abstract:

This paper proposes a novel discrete differential geometry of n-simplices. It was originally developed for protein structure analysis. Unlike previous works, we consider connection between space-filling n-simplices. Using cones of an integer lattice, we introduce tangent bundle-like structure on a collection of n-simplices naturally. We have applied the mathematical framework to analysis of protein structures. In this paper, we propose a simple encoding method which translates the conformation of a protein backbone into a 16-valued sequence.

Discrete Differential Geometry of Triangles and Escher-Style Trick Art  [PDF]
Naoto Morikawa
Open Journal of Discrete Mathematics (OJDM) , 2016, DOI: 10.4236/ojdm.2016.63013
Abstract: This paper shows the usefulness of discrete differential geometry in global analysis. Using the discrete differential geometry of triangles, we could consider the global structure of closed trajectories (of triangles) on a triangular mesh consisting of congruent isosceles triangles. As an example, we perform global analysis of an Escher-style trick art, i.e., a simpler version of “Ascending and Descending”. After defining the local structure on the trick art, we analyze its global structure and attribute its paradox to a singular point (i.e., a singular triangle) at the center. Then, the endless “Penrose stairs” is described as a closed trajectory around the isolated singular point. The approach fits well with graphical projection and gives a simple and intuitive example of the interaction between global and local structures. We could deal with higher dimensional objects as well by considering n-simplices (n > 2) instead of triangles.
Discrete Differential Geometry and the Structural Study of Protein Complexes  [PDF]
Naoto Morikawa
Open Journal of Discrete Mathematics (OJDM) , 2017, DOI: 10.4236/ojdm.2017.73014
Abstract: This paper proposes a novel four-dimensional approach to the structural study of protein complexes. In the approach, the surface of a protein molecule is to be described using the intersection of a pair of four-dimensional triangular cones (with multiple top vertexes). As a mathematical toy model of protein complexes, we consider complexes of closed trajectories of n-simplices (n=2,3,4...), where the design problem of protein complexes corresponds to an extended version of the Hamiltonian cycle problem. The problem is to find “a set of” closed trajectories of n-simplices which fills the n-dimensional region defined by a given pair of n+1 -dimensional triangular cones. Here we give a solution to the extended Hamiltonian cycle problem in the case of n=2 using the discrete differential geometry of triangles (i.e., 2-simplices).
Global Geometrical Constraints on the Shape of Proteins and Their Influence on Allosteric Regulation  [PDF]
Naoto Morikawa
Applied Mathematics (AM) , 2018, DOI: 10.4236/am.2018.910076
Abstract:
Proteins are the workhorse molecules of the cell, which are obtained by folding long chains of amino acids. Since not all shapes are obtained as a folded chain of amino acids, there should be global geometrical constraints on the shape. Moreover, since the function of a protein is largely determined by its shape, constraints on the shape should have some influence on its interaction with other proteins. In this paper, we consider global geometrical constraints on the shape of proteins. Using a mathematical toy model, in which proteins are represented as closed chains of tetrahedrons, we have identified not only global geometrical constraints on the shape of proteins, but also their influence on protein interactions. As an example, we show that a garlic-bulb like structure appears as a result of the constraints. Regarding the influence of global geometrical constraints on interactions, we consider their influence on the structural coupling of two distal sites in allosteric regulation. We then show the inseparable relationship between global geometrical constraints and protein interactions; i.e. they are different sides of the same coin. This finding could be important for the understanding of the basic mechanisms of allosteric regulation of protein functions.
Socially Anxious Tendencies Affect Autonomic Responses during Eye Gaze Perception  [PDF]
Yuki Tsuji, Sotaro Shimada
Psychology (PSYCH) , 2015, DOI: 10.4236/psych.2015.613160
Abstract: Social anxiety disorder is a common psychiatric disorder. The gaze of others is known to frequently induce social anxiety. We conducted a gaze detection experiment to examine the effects of social anxiety on autonomic response, namely heart rate (HR) response. We used the maximum HR deceleration between 0 s and 3 s after stimulus onset as an indicator of emotional stress. Participants were assigned to a high social anxiety (HSA) or low social anxiety (LSA) group on the basis of cut-off scores indicative of clinical levels of stress as per the Japanese version of the Liebowitz Social Anxiety Scale (LSAS-J). Our results showed that HR deceleration was greater for the HSA compared with the LSA group. Moreover, the higher the LSAS-J score was, the greater the increase was in HR deceleration (correlation coefficient rs = 0.52, p < 0.01). Our results suggest that the eye gaze of others can be processed as a threat in individuals with a high tendency towards social anxiety.
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