Mathematical Model for The Transmission of Lymphatic Filariasis and Its Applications

We have constructed a stochastic transmission model for lymphatic filariasis caused by Wuchereria bancrofti, and have analyzed its prevalence using computer simulations. In Pondicherry, India, where Wuchereria bancrofti has been spreading, the Vector Control Research Centre has carried out an integrated vector control strategy against malaria and filariasis for five years (1981~1985) with good results reported. Our study was aimed at evaluating the effect of vector control in the context of Pondicherry, and in particular the continuous effect for the post-control period. In this paper, we have used the LYMFASIM model proposed by Plaisier et al., the carrying capacity model by Rochet and the population dynamics model by us. In the LYMFASIM model and the carrying capacity model, we have modified the quantities of parameters in order to fit the models to the parasitological, entomological and epidemiological data in Pondicherry. We have combined the improved LYMFASIM model with the other models. Through simulations of our combinated model, we have compared the prevalence rate in the human population as well as the mean number of L3-larvae in the mosquito population, with and without vector control. As a result, the simulations show that the prevalence rate would be restrained for a long time even if only a small continuous effect of the vector control remains in the post-control period. However, the mean number of L3-larvae would recovered within a short time comparatively. This is because of the differences in life spans between human and mosquito as well as the incubation periods between the adult worm in the human host and L3-larvae in the mosquito vector

Twenty-four-hour variations in subcellular structures of rat type II alveolar epithelial cells : a morphometric study at the electron-microscopic level

Thesis--University of Tsukuba, D.M.S.(A), no. 770, 1990. 3. 23Offprint. Originally published in: Cell and tissue research, v. 256, pp. 347-353, 1989Joint authors: Shizuo Hasegawa and Yasuo UchiyamaIncludes supplementary treatise

On the Inoculation of the HST (Hamazaki) Virus Isolated From Yoshida Tumor on Emb-ryonated Eggs

HST virus which was isolated in 1950 from the roshida ascites tumor by Hamazaki and his associates is a pantropic virus which creates a unique inflammatory granulation in mice. When virus of an acute infections disease was inoculated on embryonated eggs, not only the egg membrane but also the chick embryo were infected more or less, and when the number of virus increased the chick embryo died, terminating the development of the egg. However, the tumor inducing virus which represents the Rous virus does not cause heavy disturbances in the embryo and it is well known that chick hatched from this egg can long maintain health unless it is subjected to a provocative factor. HST virus is no exception to this example and though it is inoculated on an embryonated egg it does not cause any serious disturbance on the embryo. The tissue changes of the chorio allantois infected by the &#34;Virus were the focal proliferation and necrosis of ectodermal epithelium, the proliferation of the mesenchymal cells of the mesodermal layer adjacent to these foci, accompaning infiltration of lymphoid cells and leukocytes with edema, especially eosinophilic leukocytes. By these tissue changes a terrace-shaped thickening of the membrane was the result. In the viscera of the chick embryo a special change in the liver was seen, i. e., along the edge of the liver greyish white nodules submacroscopic to miliary in size appeared. The principal pathologic change of the foci is the coagulation necrosis of the liver parenchyma and only a slight infiltration about the periphery of the foci was observed. Moreover, proliferation of mesenchymal cells occurred next to the walls of the large blood vessels of the liver (principally, the portal veins) and with the added infiltration of a small number of lymphoid cells and leukocytes sharply defined nodular foci were formed. Though this was a rare instnace, similar pathologic changes were seen also in the walls of the blood vessels of the cerebrum stem of the embryo and along the periphery local gliosis was observed.</p

Neutron scattering study of dipolar spin ice Ho2Sn2O7: Frustrated pyrochlore magnet

By means of neutron scattering techniques we have investigated the frustrated pyrochlore magnetHo2Sn2O7, which was found to show ferromagnetic spin-ice behavior below T.1.4 K by susceptibilitymeasurements. High-resolution powder neutron diffraction shows no detectable disorder of the lattice, whichimplies the appearance of a random magnetic state solely by frustrated geometry, i.e., the corner sharingtetrahedra. Magnetic inelastic scattering spectra show that Ho magnetic moments behave as an Ising spinsystem at low temperatures and that the spin fluctuation has static character. The system remains in a shortrange-ordered state down to at least T50.4 K. By analyzing the wave-vector dependence of the magneticscattering using a mean-field theory, it is shown that the Ising spins interact via the dipolar interaction.Therefore we conclude that Ho2Sn2O7 belongs to the dipolar-spin-ice family. Slow spin dynamics is exhibitedas thermal hysteresis and time dependence of the magnetic scattering

Simulations on Prevalence of Echinococcus multilocularis in Hokkaido on the Basis of Vole Population Dynamics

In our study, we have investigated the influence of the intermediate host population density on the prevalence of Echinococcus multilocularis in the definitive host using a mathematical model of transmission. For the vole population (intermediate host) in Hokkaido, a model of population dynamics has been constructed in this paper which follows the seasonal and annual fluctuations. In the northeastern area, the vole density appears to fluctuate periodically with a 4 year cycle. The prevalence of Echinococcus multilocularis in the fox population (definitive host) can be affected by the density of vole through the fox ingesting infectious voles. Therefore we have prepared a food habit function of foxes and the logistic distribution has been proposed. The simulations which have been carried out using the mathematical model for transmission of Echinococcus multilocularis together with the vole dynamics have indicated that the prevalence in foxes is correlated and synchronized with the population dynamics of vole. In addition they have also made us recognize that it is necessary to introduce a suitable food habit function into the transmission model

Pan-Arctic Sea Ice Prediction System with the MIROC Climate Model

第6回極域科学シンポジウム分野横断セッション：[IA] 急変する北極気候システム及びその全球的な影響の総合的解明―GRENE北極気候変動研究事業研究成果報告2015―11月19日（木）　国立極地研究所１階交流アトリウ

Binding enhancement of antigen-functionalized PEGylated gold nanoparticles onto antibody-immobilized surface by increasing the functionalized antigen using -sulfanyl--amino-PEG

We established a technique for constructing PEGylated gold nanoparticles (GNP) that have small compounds with almost complete functionalities on their surfaces using a newly synthesized hetero-telechelic poly(ethylene glycol) (PEG), and their association/dissociation behavior on an antibody-immobilized surface was evaluate

Unshielded fetal magnetocardiography system using two-dimensional gradiometers

We developed a fetal magnetocardiography (fMCG) system that uses a pair of two-dimensional gradiometers to achieve high signal-to-noise ratio. The gradiometer, which is based on a low-Tc superconducting quantum interference device, detects the gradient of a magnetic field in two orthogonal directions. Gradiometer position is easy to adjust by operating the gantry to drive the cryostat in both the swinging and axial directions. As a result, a fMCG waveform for 25 weeks\u27 gestation was measured under an unshielded environment in real time. Moreover, the P and T waves for 25 and 34 weeks\u27 gestation, respectively, were obtained by averaging. These results indicate that this two-dimensional gradiometer is one of the most promising techniques for measuring fetal heart rate and diagnosing fetal arrhythmia

An inverse problem for a heat equation with piecewise-constant thermal conductivity

The governing equation is $u_t = (a(x)u_x)_x$, $0\le x\le 1$, $t>0$, $u(x,0)=0$, $u(0,t)=0$, $a(1)u'(1,t)=f(t)$. The extra data are $u(1,t)=g(t)$. It is assumed that $a(x)$ is a piecewise-constant function, and $f\not\equiv 0$. It is proved that the function $a(x)$ is uniquely defined by the above data. No restrictions on the number of discontinuity points of $a(x)$ and on their locations are made. The number of discontinuity points is finite, but this number can be arbitrarily large. If $a(x)\in C^2[0,1]$, then a uniqueness theorem has been established earlier for multidimensional problem, $x\in \mathbb{R}^n, n>1$ (see MR1211417 (94e:35004)) for the stationary problem with infinitely many boundary data. The novel point in this work is the treatment of the discontinuous piecewise-constant function $a(x)$ and the proof of Property C for a pair of the operators $\{\ell_1, \ell_2 \}$, where $\ell_j:= -\frac{d^2}{dx^2} + k^2 q_j^2(x)$, $j=1,2$, and $q_j^2(x)>0$ are piecewise-constant functions, and for the pair $\{L_1, L_2 \}$, where $L_ju:=-[a_j(x)u'(x)]'+\lambda u$, $j=1,2$, and $a_j(x)>0$ are piecewise-constant functions. Property C stands for completeness of the set of products of solutions of homogeneous differential equations (see MR1759536 (2001f:34048)

Identification of host factors which protect against the development of pulmonary inflammation induced by intracellular pathogens

科学研究費助成事業 研究成果報告書：基盤研究(C)2012-2014課題番号:2459115