Mitsugu Matsushita

Niigata University, Niahi-niigata, Niigata, Japan

Are you Mitsugu Matsushita?

Claim your profile

Publications (65)108.57 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: There exists the threshold-sensitive dynamical transition between the uniform and the periodic growth modes in the domain growth of ascorbic acid crystals from its aqueous supersaturated solution film. The crystal growth induces the solution flow. Humidity controls the fluidity of the solution. The solution flow varies the film thickness. The threshold exists in the thickness of the solution film, and the crystal growth almost stops if the thickness becomes lower than the threshold.
    Journal of the Physical Society of Japan 11/2013; 83(6). · 2.09 Impact Factor
  • Source
    Hiroto Kuninaka, Mitsugu Matsushita
    [Show abstract] [Hide abstract]
    ABSTRACT: We develop a numerical growth model which can predict the statistical properties of the height distribution of Japanese children. Our previous studies have clarified that the height distribution of schoolchildren shows a transition from the lognormal to the normal distribution during puberty period. In this paper, we demonstrate by our simulations that the transition occurs owing to the variability of the onset of the puberty period.
    06/2013;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Our previous studies showed that urea in acidic broth induced swarmer morphotypes in Proteus mirabilis, but the effects to other bacterial species remain unsolved. Here we report effects of urea on morphology and size distribution of urease-negative Escherichia coli and Salmonella enterica serovar Abony grown in urea-containing broth. Statistical analysis indicated lognormal distribution of the cellular lengths below a threshold level, suggesting that the growth process of bacterial cells obeys some random multiplicative process below a threshold value, despite any other factors affecting the process above the threshold value, to produce elongated cells. In urea broth, the distribution shifted to larger size and enormously elongated cells appeared. Morphological studies in urea broth revealed that filamentous cells of E. coli and S. Abony, accompanied with incomplete chromosomal segregation without forming hyperflagellates were induced at logarithmic growth phase, unlike swarmer cells in P. mirabilis. Since cell division protein FtsZ (filamenting temperature-sensitive mutant Z) assembled round the chromosome segregated point and cells were divided into short rods after cell counts had reached to a threshold level, urea in broth was responsible for delay of chromosomal segregation.
    African journal of microbiology research 04/2013; 7(18):1780-1786. · 0.54 Impact Factor
  • Hiroto Kuninaka, Mitsugu Matsushita
    [Show abstract] [Hide abstract]
    ABSTRACT: We often find skewed distributions such as the power law distribution and the lognormal distribution in studies of complex systems. Emergence of lognormal distribution is explained based on multiplicative stochastic processes, while power-law distribution can be explained by the multiplicative stochastic process with a modification. Thus, multiplicative process and lognormal distribution can serve as a starting point to discuss the statistical aspect of complex systems. In this paper, we show some economic and social phenomena in which lognormal and its related distributions can be observed to discuss their origins in terms of multiplicative growth.
    08/2012;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Complex systems have recently attracted much attention, both in natural sciences and in sociological sciences. Members constituting a complex system evolve through nonlinear interactions among each other. This means that in a complex system the multiplicative experience or, so to speak, the history of each member produces its present characteristics. If attention is paid to any statistical property in any complex system, the lognormal distribution is the most natural and appropriate among the standard or ``normal'' statistics to overview the whole system. In fact, the lognormality emerges rather conspicuously when we examine, as familiar and typical examples of statistical aspects in complex systems, the nursing-care period for the aged, populations of prefectures and municipalities, and our body height and weight. Many other examples are found in nature and society. On the basis of these observations, we discuss the possibility of sociological physics.
    Journal of The Physical Society of Japan - J PHYS SOC JPN. 01/2011; 80.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The statistics of isothermal lines and loops of the Cosmic Microwave Background (CMB) radiation on the sky map is studied and the fractal structure is confirmed in the radiation temperature fluctuation. We estimate the fractal exponents, such as the fractal dimension $D_{\mathrm{e}}$ of the entire pattern of isothermal lines, the fractal dimension $D_{\mathrm{c}}$ of a single isothermal line, the exponent $\zeta$ in Kor\v{c}ak's law for the size distribution of isothermal loops, the two kind of Hurst exponents, $H_{\mathrm{e}}$ for the profile of the CMB radiation temperature, and $H_{\mathrm{c}}$ for a single isothermal line. We also perform fractal analysis of two artificial sky maps simulated by a standard model in physical cosmology, the WMAP best-fit $\Lambda$ Cold Dark Matter ($\Lambda$CDM) model, and by the Gaussian free model of rough surfaces. The temperature fluctuations of the real CMB radiation and in the simulation using the $\Lambda$CDM model are non-Gaussian, in the sense that the displacement of isothermal lines and loops has an antipersistent property indicated by $H_{\mathrm{e}} \simeq 0.23 < 1/2$.
    Journal of the Physical Society of Japan 12/2010; · 2.09 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We have experimentally investigated size distribution of bacterial cells at the circumference of homogeneously spreading disk-like colonies formed by Bacillus subtilis, and found that the size distribution of bacterial cells shows lognormal. We have developed a phenomenological model based on the experimental results for the growth process of bacterial cells and confirmed that the model reproduces a lognormal distribution of bacterial cell size which is very close to our experimental result. Our results indicate that both the lognormal distributions of cell cycle and cell growth rate are essential for the lognormal distribution of bacterial cell size.
    Journal of the Physical Society of Japan 01/2010; 79. · 2.09 Impact Factor
  • Source
    Hiroto Kuninaka, Yu Mitsuhashi, Mitsugu Matsushita
    [Show abstract] [Hide abstract]
    ABSTRACT: We study height distributions of Japanese schoolchildren based on the statictical data which are obtained from the school health survey by the ministry of education, culture, sports, science and technology, Japan . From our analysis, it has been clarified that the distribution of height changes from the lognormal distribution to the normal distribution in the periods of puberty. Comment: 2 pages, 2 figures, submitted to J. Phys. Soc. Jpn.; resubmitted to J. Phys. Soc. Jpn. after some revision
    Journal of the Physical Society of Japan 08/2009; · 2.09 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A bacterial strain isolated from the oral cavity of a healthy dog revealed an unusual colony formation in nebular appearance on agar plates. The isolated bacterial strain was Gram-positive, spore-forming rod with peritrichous flagella, and grown under aerobic conditions, but unable to grow at 45 degrees C. The strain was tentatively classified as Paenibacillus alvei according to the biochemical properties and the 16S rRNA gene sequence. The isolate exhibits collective locomotion on solid agar plates. The bacterial motility was inhibited with EDTA and was restored by adding magnesium. We concluded that magnesium ion is essential for collective locomotion of P. alvei. This suggests that EDTA is useful for inhibition of biofilm formation.
    Journal of Veterinary Medical Science 03/2009; 71(2):147-53. · 0.88 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We have studied the morphological diversity and change in bacterial colonies, using the bacterial species Escherichia coli, as a function of both agar concentration Ca and nutrient concentration Cn. We observed various colony patterns, classified them into four types by pattern characteristics and established a morphological diagram by dividing it into four regions. They are regions A [diffusion-limited aggregation (DLA)-like], B (Eden-like), C (concentric-ring), and D (fluid-spreading). In particular, we have observed a concentric-ring colony growth for E. coli. We focused on the periodic growth in region C and obtained the following results: (i) A colony grows cyclically with the growing front repeating an advance (migration phase) and a momentary rest (consolidation phase) alternately. (ii) The growth width L and the bulge width W in one cycle decrease asymptotically to certain values, when Ca is increased. (iii) L does not depend on Cn, while W is an increasing function of Cn. Plausible mechanisms are proposed to explain the experimental results, by comparing them with those obtained for other bacterial species such as Proteus mirabilis and Bacillus subtilis.
    Journal of the Physical Society of Japan 01/2009; 78(7). · 2.09 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Humidity-temperature conditions for the emergence of various domain patterns of ascorbic acid crystal are identified, where the crystal grows from its thinly spreading aqueous solution by solvent evaporation. In particular, under a low-humidity condition, the coexistent pattern is formed by two domains having different growth rates. In the faster growing domain, there exists a clear time delay between the crystal growth in the solution and the drying of the crystal surface. From the shape of the domain boundary in the coexistent pattern, the growth rate ratio between the two domains can be estimated.
    Journal of the Physical Society of Japan 01/2009; 78(7). · 2.09 Impact Factor
  • Hiroto Kuninaka, Mitsugu Matsushita
    [Show abstract] [Hide abstract]
    ABSTRACT: We investigate the rank-size distribution of cities in Japan by data analysis and computer simulation. From our previous data analysis of the census data after World War II, it has been clarified that the power exponent of the rank-size distribution of cities changes with time and Zipf’s law holds only for a restricted period. We show that Zipf’s law broke down owing to the great mergers and recovered by investigating the time evolution of the rank-size distribution of cities without mergers.
    Complex Sciences, First International Conference, Complex 2009, Shanghai, China, February 23-25, 2009. Revised Papers, Part 1; 01/2009
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Polar flagellated Pseudomonas aeruginosa PAO1 demonstrated extensive spreading growth in 2 days on 1.5% agar medium. Such spreading growth of P. aeruginosa PAO1 strains was absent on Luria-Bertani 1.5% agar medium, but remarkable on Davis minimal synthetic agar medium (especially that containing 0.8% sodium citrate and 1.5% Eiken agar) under aerobic 37 degrees C conditions. Analyses using isogenic mutants and complementation transformants showed that bacterial flagella and rhamnolipid contributed to the surface-spreading behavior. On the other hand, a type IV pilus-deficient pilA mutant did not lose the spreading growth activity. Flagella staining of PAO1 T cells from the frontal edge of a spreading colony showed unipolar and normal-sized rods with one or two flagella. Thus, the polar flagellate P. aeruginosa PAO1 T appears to swarm on high-agar medium by producing biosurfactant rhamnolipid and without differentiation into an elongated peritrichous hyperflagellate.
    FEMS Microbiology Letters 04/2008; 280(2):169-75. · 2.05 Impact Factor
  • Source
    Hiroto Kuninaka, Mitsugu Matsushita
    [Show abstract] [Hide abstract]
    ABSTRACT: We study rank-size distribution of cities in Japan on the basis of data analysis. From the census data after World War II, we find that the rank-size distribution of cities is composed of two parts, each of which has independent power exponent. In addition, the power exponent of the head part of the distribution changes in time and Zipf's law holds only in a restricted period. We show that Zipf's law broke down due to both of Showa and Heisei great mergers and recovered due to population growth in middle-sized cities after the great Showa merger. Comment: 6 pages, 9 figures, resubmitted to J. Phys. Soc. Jpn
    Journal of the Physical Society of Japan 02/2008; · 2.09 Impact Factor
  • Naoki Kobayashi, Kaoru Kohyama, Yo Sasaki, Mitsugu Matsushita
    [Show abstract] [Hide abstract]
    ABSTRACT: Scaling property of the shape of fragments which were produced by masticating raw carrots has been studied experimentally and theoretically. Mastication experiments showed that most fragments have more or less isotropic shapes which are independent of the number of chewing strokes, whereas larger fragments than a crossover size have complicated shapes. Since the crossover size had the structure which was dependent on the number of chewing strokes, we have tried to propose dynamic scaling hypothesis analogous to the case of growing self-affine interface. It was found that the dynamic scaling yields fairly accurate values of the scaling exponents. Our results will provide a new observation and insight of not only sequential fragmentation but also construction for physiological measurement.
    Journal of the Physical Society of Japan 04/2007; 76(4). · 2.09 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Anaerobiosis of Pseudomonas aeruginosa in infected organs is now gaining attention as a unique physiological feature. After anaerobic cultivation of P. aeruginosa wild type strain PAO1 T, we noticed an unexpectedly expanding colony on a 1.5% agar medium. The basic factors involved in this spreading growth were investigated by growing the PAO1 T strain and its isogenic mutants on a Davis high-agar minimal synthetic medium under various experimental conditions. The most promotive environment for this spreading growth was an O(2)-depleted 8% CO(2) condition. From mutational analysis of this spreading growth, flagella and type IV pili were shown to be ancillary factors for this bacterial activity. On the other hand, a rhamnolipid-deficient rhlA mutant TR failed to exhibit spreading growth on a high-agar medium. Complementation of the gene defect of the mutant TR with a plasmid carrying the rhlAB operon resulted in the restoration of the spreading growth. In addition, an external supply of rhamnolipid or other surfactants (surfactin from Bacillus subtilis or artificial product Tween 80) also restored the spreading growth of the mutant TR. Such activity of surfactants on bacterial spreading on a hard-agar medium was unique to P. aeruginosa under CO(2)-rich anaerobic conditions.
    Microbiology and Immunology 02/2007; 51(8):703-12. · 1.55 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A scaling hypothesis for the standard deviation of the height of growing interfaces is proposed by extending the Family–Vicsek (FV) scaling hypothesis. A data-collapsing method is adopted for estimating values of three exponents , , and z, which characterize, respectively, the roughness, growth, and dynamic properties of growing interfaces. The estimation is carried out through , which is a function of both the time and the width of the interfaces. The advantages of the present extended scaling hypothesis are as follows: (A) The value of can be obtained even if the data for in terms of t are few so that its value is not determined precisely from the slope of the ln vs ln t plot. (B) Different scaling relations can be obtained during the time evolution of interface growth. (C) By introducing a new exponent, which represents the time dependence of for a short width, a scaling argument is possible even for growing interfaces that do not satisfy the FV scaling relation. Successful applications are carried out to a few numerical models and a paper-wetting experiment.
    Journal of the Physical Society of Japan 01/2007; 76(10). · 2.09 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Long-tailed distributions in biological systems have been studied. First, we found that lognormal distributions show excellent fit with various data for the duration distribution of disability in aged people, irrespective of their severity and gender. The robust lognormal distribution of disability implies that the incidence of diseases can be completed by many independent subprocesses in succession. Next, we studied food fragmentation by human mastication. A lognormal distribution well fits to the entire region for masticated food fragments for a small number of chewing strokes. Furthermore, the tail of the fragment-size distribution changes from the lognormal distribution to a power-law one as the chewing stroke number increases. The good data fitting by the lognormal and power-law distribution implies that two functions of mastication, a sequential fragmentation with cascade and randomness and a lower threshold for fragment size, may affect the size distribution of masticated food fragments.
    01/2007;
  • Source
    Yo Sasaki, Hiroto Kuninaka, Naoki Kobayashi, Mitsugu Matsushita
    [Show abstract] [Hide abstract]
    ABSTRACT: Population characterizes collective behaviors of human beings. In this paper we investigate cumulative population distribution of municipalities (cities, towns, and villages) of Japan to show that each of them can be represented by a characteristic distribution function. We also introduce a numerical model for population dynamics to explain the origin of the distributions. From our analysis it has become clear that each distribution originates from the lower and upper bounds of population in the definitions of cities and towns.
    Journal of the Physical Society of Japan 01/2007; 76(7). · 2.09 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Fragment-size distribution has been studied experimentally by masticating raw carrot and fish gel. Lognormal distribution shows partly-good fit with various data. We have found that the fit of two-lognormals distribution is extremely good up to the entire region for masticated food fragments. The excellent data fitting by two-lognormals distribution implies that two main functions of mastication, a sequential fragmentation with randomness and size segregation, affect the size distribution of masticated food fragments.
    01/2006;

Publication Stats

618 Citations
108.57 Total Impact Points

Institutions

  • 2000–2008
    • Niigata University
      • • Department of Applied Biological Chemistry
      • • Division of Bacteriology
      Niahi-niigata, Niigata, Japan
  • 1996–2008
    • Chuo University
      • Department of Physics
      Edo, Tōkyō, Japan
  • 2004–2007
    • Waseda University
      • Department of Physics
      Edo, Tōkyō, Japan