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Adherence is an essential and prerequisite step for the colonization of mucosal surfaces by enterotoxigenic Escherichia coli (ETEC). We studied the effect of bovine lactoferrin (BLF) on the adherence of ETEC to human epithelial cells in vitro, and to intestinal mucosa of ICR germfree mice in vivo. In the in vitro study, BLF was found to inhibit the adherence of ETEC. This adhesion-inhibiting activity of BLF was found to lessen with decreasing BLF concentration, but the data obtained suggest a positive inhibitory effect of BLF against the adhesion of ETEC cells. In the in vivo study, the counts of adherent bacteria in various sections of the intestinal tract (duodenum, jejunoileum, and large intestine) were lower in the BLF group than in the control group, suggesting the possible action of BLF as an intestinal tract adherence-blocking agent with regards to ETEC.

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Occult blood test for the screening of colon cancer has been made by immunological method using latex agglutination for 4 years since 1988. A total of 35,139 persons have received the screening test and out of 1886 persons, that is, 5.4% showed positive. Five hundred seventy of the positive result subjects (30.2%) underwent barium enema examination. Three hundred fifty nine subjects (62.8%) showed some abnormal findings. They underwent colonoscopic examination and 45 of them (7.9%) had colon cancer. Twenty six of these were of early stage type and 19 persons were of advanced stage.

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A model membrane constructed from a Millipore filter, whose pores are filled with dioleyl phosphate molecules, exhibits a self-oscillation of the electric potential with a period of about a few seconds in the presence of a salt-concentration difference, pressure difference and/or electric current across the filter. In this paper, the effects of chemicals such as KCl, CaCl2, pH and sucrose on the self-oscillation are investigated experimentally. These chemical substances are shown to alter the characteristic properties as the frequency of oscillation. Theoretical consideration of electrochemical interaction between these substances and DOPH molecules gives a fairly good explanation of the observed results.

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A simple theoretical model is presented for simulating the self-sustained oscillations of electric potential and pH at an oil/water interface appearing in a two-phase system composed of 2-nitropropane solution containing picrate acid and an aqueous solution of cetyltrimethylammonium bromide. In the present model, a well-known condition necessary for the occurrence of self-sustained oscillations, i.e., the presence of a positive feedback process far from equilibrium, is taken into account in a set of kinetic equations to describe simplified characters of the following two processes: (i) a cooperative formation of ion pair complexes at the interface, and (ii) supply of picrate anions and cetyltrimethylammonium cations to the interface accompanied by release of ion pair complexes to the organic phase. The numerical solutions of the present equations are shown to reproduce fairly well the characteristic properties of the oscillation of electric potential and pH such as wave forms and frequencies.

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A theory is presented to explain the dynamic characteristics of an electric potential and the resistance of a surface membrane during the formation of a protoplasmic droplet isolated from Nitella. Basic equations are coupled ones for describing ion concentrations near the surface of the droplet, active and passive ion fluxes on the surface, and kinetics of membrane-constituting molecules diffusing from the inside of the protoplasm. The present results give a good explanation of the observed kinetics of electric properties throughout the formative process of surface membranes after the ion concentrations are replaced by lower ones. The results can also explain well the observed data on the steady state. Oscillatory changes in the membrane potential induced by ions strongly adsorbed on the surface membrane are discussed in relation to growth and regeneration phenomena in biological systems such as bean roots and Acetabularia.

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For an artificial membrane prepared by infiltrating dioleyl phosphate (DOPH) into pores of a Millipore filter, we propose a theoretical model for explaining observed data on electric behavior, such as d.c. current-voltage characteristics and self-sustained oscillations of the electric potential. The model consists of a simple electric circuit composed of electric resistances and capacitances as given functions of internal variables which represent conformational states of DOPH molecules and salt concentration inside the pore concerned. The kinetic equations for these variables are the same as those presented previously for describing a phase transition of DOPH. except for a slight modification taking account of effects of salt accumulation inside the pore. The present theory can describe well the I-V hysteresis and various features of spike-like oscillations with long periods of up to a few hours in the absence of external force and also short-period oscillations with periods of the order of 1 s under pressure difference.

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The light emitted by a stabilized 633-nm He-Ne transverse Zeeman laser (STZL) is composed of two linearly polarized components that are perpendicular to each other. Optical frequencies of the two components are different, and therefore the light changes its polarization with time. The change is represented on the Poincaré sphere as a spin along the equator containing S(2) and S(3) axes of the sphere. Three types of polarimetry and two types of interferometry using an STZL are proposed and experimentally demonstrated. Comparisons of these techniques with the existing ones are also reported.

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Tuning characteristics of power, intramode beat frequency, and polarization of 633-nm internal mirror lasers filled with natural Ne or (20)Ne are studied. It is found that the tuning curve of a polarization signal is S-shaped for the natural Ne laser, whereas that of the intramode beat frequency is S-shaped for the (20)Ne laser. The characteristic parameters of the tuning curve of the intramode beat frequency are determined. The axial modes of a (3)He-(20)Ne laser are collapsed into one by a transverse magnetic field and frequency stabilized by cooling the laser tube with a fan to keep the intramode beat constant. Frequency fluctuation of 3 x 10(-10) is obtained by the Allan variance analysis for the integration period range of 0.1-100 sec. Absolute accuracy and interinstrumental reproducibility of stabilized wavelengths can be expected for a (3) He-(20)Ne transverse Zeeman laser stabilized at the central frequency of the intramode beat.

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A total of 387 yeasts from the contents of the digestive tracts of domestic animals and poultry were identified by slide agglutination tests using factor antisera and urease tests. The results of this serological test were very satisfactory with respect to accuracy and rapidity, particularly when performed in combination with concomitant physiological tests only for assimilation of inositol and potassium nitrate. It may be concluded that such a combination of serological and biological tests is very useful for identifying yeast strains from various sources.

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A new method of moire topography is described. This encompasses two processes: recording of the deformed grating projected onto a 3-D object, and posterior development of contour moire from the record. The development of contour moire is realized by projecting a linear grating onto a photographic print of the record of the deformed grating, using a photographic enlarger. By this new method, a technique for describing a 3-D object by means of the slope of facets composing the object is made possible.