检索结果-南通市图书馆

Modified Kuramoto Phase Model for Simulating Cardiac Pacemaker Cell Synchronization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics 2017年第9期8卷 1227-1238页

作者： Motohisa osaka Department of Basic Science Nippon Veterinary and Life Science University Tokyo Japan

It has been suggested that sick sinus syndrome, which is due to the dysfunction of the sinus node, may result from the sparser gap junctions and/or lower intrinsic frequencies of pacemaker cells that occur with aging. Hence, in this paper, the synchronization mechanism of pacemaker cells that lie in the sinus node of the heart is examined using a modified Kuramoto phase model. Although each element always interacts with all the others in the Kuramoto phase model, in the proposed model, each element interacts only with the neighbors over a certain time (called the interaction time) during Phase 4 of the action potential. The pacemaker cell elements are arranged on a square lattice, and each element connects with the elements surrounding it. The results indicate that the diversity of intrinsic frequencies of pacemaker cells may be necessary for synchronization. Moreover, increasing the proportion of invalid connections causes the elements to take more time to synchronize until eventually they do not synchronize at all, and decreasing the intrinsic frequencies of the elements prevents them from synchronizing. Probably these elucidate the cause of sick sinus syndrome.

关键词： Synchronization Sick Sinus Syndrome Oscillator Overdrive Suppression Test Gap Junction

Probability Theory Predicts That Group Survival May Be Guaranteed for Groups with More Than 10 Elements

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics 2017年第12期8卷 1745-1760页

作者： Motohisa osaka Department of Basic Science Nippon Veterinary and Life Science University Tokyo Japan

The purpose of this study is to find out the critical number of elements needed for group survival. Taking a probabilistic approach, how the lifetime of a group consisting of several elements depends on the number of elements and the probability distribution of their lifetimes is investigated. Four probability distributions are examined: an exponential distribution, a uniform distribution, a parabolic distribution, and a pointed distribution composed of two parabolas. The lifetime of the group is defined as the expected value of the maximum lifetime of the elements in that group. The probability distribution of this maximum shifts to the right as the number of elements increases, and the expected value of the lifetime of each element eventually becomes less than the lower limit of this distribution. The number of elements in this case is defined as the critical number of elements needed for group survival. Hence, if the number of elements is larger than the critical number needed for group survival, the lifetime of the group is guaranteed to be longer than the expected lifetime of one element. The findings are in the following. The critical number needed for group survival is inversely proportional to the expected lifetime of one element, regardless of the probability distribution used. It decreases as for an exponential distribution, and as in case of the others, where N is the number of elements of the group. Because a probability distribution defined over a finite range is assumed to be reasonable in practice, a group consisting of more than 10 elements should survive well.

关键词： Lifetime Neuron Cerebral Atrophy Hippocampus Memory

A Mathematical Model Reveals That Both Randomness and Periodicity Are Essential for Sustainable Fluctuations in Stock Prices

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics 2019年第6期10卷 383-396页

作者： Motohisa osaka Department of Basic Science Nippon Veterinary and Life Science UniversityMusashinoTokyoJapan

Is it true that there is an implicit understanding that Brownian motion or fractional Brownian motion is the driving force behind stock price fluctuations? An analysis of daily prices and volumes of a particular stock revealed the following findings: 1) the logarithms of the moving averages of stock prices and volumes have a strong positive correlation, even though price and volume appear to be fluctuating independently of each other, 2) price and volume fluctuations are messy, but these time series are not necessarily Brownian motion by replacing each daily value by 1 or –1 when it rises or falls compared to the previous day’s value, and 3) the difference between the volume on the previous day and that on the current day is periodic by the frequency analysis. Using these findings, we constructed differential equations for stock prices, the number of buy orders, and the number of sell orders. These equations include terms for both randomness and periodicity. It is apparent that both randomness and periodicity are essential for stock price fluctuations to be sustainable, and that stock prices show large hill-like or valley-like fluctuations stochastically without any increasing or decreasing trend, and repeat themselves over a certain range.

关键词： Stock Price Volume Brownian Motion Randomness

Electronic characteristics of sandwich-type lanthanide octaethylporphyrins

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 1994年第3期12卷 193-198页

作者： JIANG, Jian-ZhuangChemistry Department, Peking University, Beijing 100871, China MACHIDA, Ken-ichi YAMAMOTO, Eiji ADACHI, Gin-yaDepartment of Applied Chemistry, Faculty of Engineering, osaka University, osaka 565, Japan Chemistry Department Peking University Beijing 100871 China Department of Applied Chemistry Faculty of Engineering Osaka University Osaka 565 Japan

The electronic behavior of sandwich-type rare earth octaethylporphyrinates Ln(oep)2 and Ln2(oep)3 (Ln=Ce, Pr and Eu) was characterized by measurements of the UV-vis or near infrared spectra and D.C. conductivity. However, the conductivity values measured at room temperature were distributed in an order of 10-7 to 10-8 ***-1 even after the partial oxidation of complex with the complexes with iodine and no remarkable change was observed among the complexes such as LnIV(Por2-)2 (Ln=Ce) and LnIV(Por2-)(Por.-) (Ln=Ce) or Ln2III(Por2-)3 and LnIII2(Por2-)2(Por-).

关键词： Sandwich-type lanthanide octaethylporphrin electrical conductivity.

CONSTRUCTION OF A GENOMIC DNA LIBRARY WITH ATA VECTOR AND ITS APPLICATION IN CLONING OF THE PHYTOENE SYNTHASE GENE FROM THE CYANOBACTERIUM SPIRULINA PLATENSIS M-135

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Oceanology and Limnology 1998年第S1期16卷 17-24页

作者： Yoshikazu Kawata Shin-ichi Yano Hiroyuki Kojima(osaka Mational Research Institute. Agency of Industrial Science and Technology, Ikeda, osaka 563, Japan)

An efficient and simple method for constructing a genomic DNA library using a TAcloning vector is presented. It is based on the sonicative cleavage of genomic DNA and modification offragment ends with Taq DNA polymerase, followed by ligation using a TA vector. This method was ap-plied for cloning of the phytoene synthase gene crtB from Spirulina platensis. This method is useful whengenomic DNA cannot be efficiently digested with restriction enzymes, a problem often encountered duringthe construction of a genomic DNA library of cyanobacteria.

关键词： genomic library Spirulina phytoene synthase carotenoid

EXTRACELLULAR RELEASE OF β-LACTAMASE BY OSMOTIC SHOCK IN SYNECHOCOCCUS TRANSFORMANT

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Oceanology and Limnology 1998年第S1期16卷 105-108页

作者： Shin-ichi Yano Yoshikazu Kawata Hiroyuki Kojima(osaka National Research Institute, Agency of Industrial Science and Technology, Ikeda, osaka 563, Japan )

A unicellular cyanobacterium Synechococcus sp. strain PCC 7002 was transformedwith plasmid pQL1, on which β-lactamase gene (bla) and β-galactosidase gene (lacZ) were *** transformant cells released β-lactamase into medium by an abrupt drop of osmotic pressure. This re-sult indicates that this cyanobacterium recognizes and processes the signal sequence of β-lactamase, andaccumulates the enzyme in periplasm. Repeated release of β-lactamase was possible by repeated osmoticshocks without impairing cell viability. On the other hand, most of the β-galactosidase remained in cyto-plasm under the osmotic shock.

关键词： Synechococcus perienzyme β-lactamase osmotic shock

Evaluation of the sperm DNA fragmentation index in infertile Japanese men by in-house flow cytometric analysis

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2022年第1期24卷 40-44页

作者： Akiyoshi osaka Hiroshi Okada Sae Onozuka Takashi Tanaka Toshiyuki Iwahata Yukihito Shimomura Yoshitomo Kobori Kazutaka Saito Kouhei Sugimoto Department of Urology Dokkyo Medical University Saitama Medical Center2-1-50 MinamikoshigayaKoshigayaSaitama 343-8555Japan International Center for Reproductive Medicine Dokkyo Medical University Saitama Medical Center2-1-50 MinamikoshigayaKoshigayaSaitama 343-8555Japan

Semen analysis has long been used to evaluate male ***,several sperm function tests have been *** those,the sperm DNA fragmentation index(DFI),which describes the status of the sperm DNA,is thought to be a suitable parameter for evaluating male ***,there have been no large-scale studies on the sperm DFI of Japanese ***,we investigated the feasibility of using an in-house flow cytometry-based sperm DFI analysis based on the sperm DNA fragmentation test of sperm chromatin structure assay(SCSA)to assess male fertility in *** study enrolled 743 infertile and 20 fertile Japanese *** evaluate reproducibility,inter-and intraobserver precision was analyzed.A receiver operating characteristic curve analysis was used to set a cutoff value for the sperm DFI to identify men who could father children by timed intercourse or intrauterine *** variability of the sperm DFI among fertile volunteers was *** relationship between semen parameters and the sperm DFI was assessed by Spearman’s rho test.A precision analysis revealed good reproducibility of the sperm *** cutoff value of sperm DNA fragmentation in infertile men was 24.0%.Semen volume had no relationship with the sperm *** concentration,sperm motility,total motile sperm count,and percentage of normal-shaped sperm were significantly and negatively correlated with the sperm *** median sperm DFI was smaller in fertile volunteers(7.7%)than that in infertile men(19.4%).Sperm DNA fragmentation analysis can be used to assess sperm functions that cannot be evaluated by ordinary semen analysis.

关键词： DNA fragmentation flow cytometry male infertility semen analysis spermatozoa

INTERFACIAL STRUCTURE AND PHASE REACTION IN SiC/NiCr ALLOY JOINT

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2000年第1期13卷 28-32页

作者： J. C. Feng M. Naka J. C. Schuster(School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China Joining and Welding Research Institute, osaka University, Mihogaoka 11 - 1, Ibaraki, osaka 567, Japan Institute of P

Bonding of SiC to SiC using Ni and Ni - 25at%Cr foils was performed at high *** structures and reaction phases were investigated by EPMA analyses and XRD diffraction method, re- spectively. At a bonding temperature of 1273K Ni reacts with SiC and forms various Ni silicides con- taining graphite baside SiC. Ni3Si without graphite was formed at Ni *** interface structure of SiC/Ni joint was SiC/Ni2Si + C/Ni31 Si12 + G/Ni3 Si/Ni. At the interface between SiC and Ni- 25at%Cr alloy the Ni silicide was only Ni2Si at the same bonding temperature,and further(Cr, Ni)7 (Si, C)3 carbide was formed between Ni silicide + graphite zone and Ni - 25at%Cr *** interface structure of SiC/Ni - 25at%Cr alloy was SiC/Ni2Si + C/(Cr, Ni)7 (Si, C)3+Ni(ss. Cr, Si)/Ni - 25at%Cr.

关键词： interfacial structure phase reaction SiC Ni - Cr

Quantitative evaluation of perceived depth of transparently-visualized medical 3D data presented with a multi-view 3D display

在线全文

学校读者我要写书评

暂无评论

International Journal of Modeling, Simulation, and Scientific Computing 2018年第3期9卷 115-130页

作者： Yuichi Sakano Yurina Kitaura kyoko Hasegawa Roberto Lopez-Gulliver Liang Li Hiroshi Ando Satoshi Tanaka Center for Information and Neural Networks(CiNet)National Institute of Information and Communications Technology and osaka University 2B6CiNet1-4 Yamadaoka SuitaOsaka 565-0871Japan Graduate School of Frontier Biosciences Osaka University 1-4 YamadaokaSuitaOsaka565-0871Japan Graduate School of Information Science and Engineering Ritsumeikan University 1-1-1 Noji-higashi KusatsuShiga 525-8577Japan College of Information Science and Engineering Ritsumeikan University 1-1-1 Noji-higashi KusatsuShiga 525-8577Japan

Transparent visualization is used in many fields because it can visualize not only the frontal object but also other important objects behind *** in many situations,it would be very important for the 3D structures of the visualized transparent images to be perceived as they are simulated,little is known quantitatively as to how such transparent 3D structures are *** address this question,in the present study,we conducted a psychophysical experiment in which the observers reported the perceived depth magnitude of a transparent object in medical images,presented with a multiview 3D *** the visualization,we employed a stochastic point-based rendering(SPBR)method,which was developed recently as a technique for efficient *** depth of the transparent object was smaller than the simulated *** found,however,that such depth underestimation can be alleviated to some extent by(1)applying luminance gradient inherent in the SPBR method,(2)employing high opacities,and(3)introducing binocular disparity and motion parallax produced by a multi-view 3D display.

关键词： Transparent visualization automultiscopic 3D image psychophysics.