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  • Author: J.-H. Han x
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J. Cui, Z. Wang and H. Han

Abstract

Congenital transmission of T. spiralis infectio in BALB/c mice was studied. Pregnant mice were each infected with 300 larvae 5, 7, 15 and 17 days after fertilization. Newborn mice were examined by artificial digestion of muscles. Out of 6 offspring born to the mother-mouse infected 7 days after fertilization, two offspring were found to be infected, 7 and 24 larvae were recovered respectively. Other 7 female mice were first infected with T. spiralis larvae and then gestated, only the offspring born to the mother-mice fertilized 8 and 22 days after infection were found to be infected with a larval burden ranging from 1–3 larvae per animal. All of the larvae recovered from the offspring were the non-encapsulated larvae. The cross-fostering in which one-day old young born to healthy mother-mice were nursed by infected mothers for 21 days, showed that no young were found to be infected. These findings showed that tansplacental transmission of T. spiralis could occur in mice, if the female were infected during mid-pregnancy or fertilized in 1 month after infection (e.g., infected in one month before fertilization). The larvae transmitted from maternal-to-neonatal mice may be migrating. Transmammary transmission of T. spiralis was not observed.

Open access

J.-H. Han and Y.-C. Kim

Abstract

This is a study of the effects of temperature of injection mold on the injection molded article. By supplying water of the proper temperature in the cooling line of mold in the cooling process, the mold was the appropriate temperature, and the deformation of the injection molded article was examined according to the mold temperature. In this study, we conducted simulation analysis and experiments, and the results were analyzed. The minimum deformation of the injection molded article model obtained by supplying 50°C water in the cooling line is 0.003 mm, and the maximum deformation was 0.813 mm. Injection molded article models obtained by supplying 20°C water were found to be a minimum of 0.002 mm, with deformation of up to 0.761 mm. When comparing both conditions, the error rate of injection molded article obtained by supplying 20°C water in the mold cooling line was lower by about 0.18%.

Open access

A. M. Mathai and H. J. Haubold

Abstract

In this article we examine the densities of a product and a ratio of two real positive scalar random variables x1 and x2, which are statistically independently distributed, and we consider the density of the product u1 = x1x2 as well as the density of the ratio u2 = x2/x1 and show that Kober operator of the second kind is available as the density of u1 and Kober operator of the first kind is available as the density of u2 when x1 has a type-1 beta density and x2 has an arbitrary density. We also give interpretations of Kober operators of the second and first kind as Mellin convolution for a product and ratio respectively. Then we look at various types of generalizations of the idea thereby obtaining a large collection of operators which can all be called generalized Kober operators. One of the generalizations considered is the pathway idea where one can move from one family of operators to another family and yet another family and eventually end up with an exponential form. Common generalizations in terms of a Gauss′ hypergeometric series is also given a statistical interpretation and put on a more general structure so that the standard generalizations given by various authors, including Saigo operators, are given statistical interpretations and are derivable as special cases of the general structure considered in this article.

Open access

H. Han, X. M. Sun, Y. H. Xie, J. Feng and S. G. Zhang

Abstract

Adventitious root development is crucial for cutting propagation in hybrid larch. In the present study, semilignified cuttings of Larix kaempferi × L. olgensis clones were used to study the morphological and anatomical changes during the different development stages and compare the changes in contents of endogenous phytohormone in two clones with evidently different rooting capacity (25-5 and 23-12), and the effects of exogenous Indole-3-Butyric Acid (IBA) on phytohormone content of a very low native rooting capacity clone (8-9) during the development of adventitious roots. The results showed that the development of adventitious root in semi-lignified cuttings involves three key stages: root cell dedifferentiation and division (14-18 DAC); meristem formation and development (25-35 DAC); root formation and elongation (50-55 DAC). The endogenous phytohormones play a key role during adventitious root development. For 25-5 and 23-12, the level of endogenous phytohormones, especially the ABA content, has an important effect on rooting capacity. For the effects of IBA on 8-9, except lower ABA content, the temporary peak of IAA on the 1 DAC was important for initiating the rooting process. The ratio of (IAA + GA3 + ZR)/ABA can be used as an indicator of rooting capacity. The anatomical and physiological data described here for semi-lignified cuttings of L. kaempferi × L. olgensis clones improves our knowledge of adventitious roots development. Our study will also benefit future research on examining the molecular mechanisms of the adventitious roots development in hybrid larch.

Open access

H.Y. Ryu, S.C. Kwon, M.H. Han, Y.S. An, J.S. Lee and J.H. Lee

Abstract

The effects of processing parameters on the morphology change in a Si deposit recovered by means of molten salt electrorefining are evaluated using electrochemical techniques such as cyclic voltammetry and chronopotentiometry at 800°C. It was found that concentration of K2SiF6 and current density were important parameters in determining deposit size. Higher concentrations of K2SiF6 were effective in coarsening the silicon deposit and decreasing the cell potential. Silicon nanofiber was recovered at 5 wt% of K2SiF6 whereas dense particles were prepared at 30 and 50 wt% of K2SiF6. The morphology of the Si deposit was determined by the concentration of Si in the electrolyte which is related to the formation of crystal and growth of Si. The formation mechanism of the Si deposit was interpreted by using high resolution TEM as well as electrochemical properties.

Open access

S. H. Kim, Y. S. Jang, J. G. Han, H. G. Chung, S.W. Lee and K. J. Cho

Abstract

Dendropanax morbifera Lev. (Araliaceae) is an economically important tree species because of its role in the production of golden varnishes as well as its use as an ornamental plant. As an endemic tree species of Korea, it is restricted to the southern parts of Korea as isolated populations. In this study, eight natural populations of D. morbifera were investigated by starch-gel electrophoresis in an attempt to determine the extent of its genetic diversity. Out of 8 natural populations, the Suak population in Jeju island showed the lowest level of genetic diversity, while the Wando island population in Jeonnam showed the highest level of genetic diversity. Levels of genetic diversity maintained in D. morbifera (A/L =1.5, P95 = 27.3%, Ho = 0.100, He = 0.095) were notably lower than those of other tree species with wider and more continuous geographic distributions. The reasons for the low level of genetic diversity in D. morbifera might be due to the genetic drift caused by artificial disturbances. Most of the total genetic diversity (96%) was found within the populations. The UPGMA dendrogram based on Nei’s genetic distance did not show any particular geographic patterns. The low level of genetic diversity suggested that there should be an urgent emphasis on the conservation study of this species.

Open access

J.Y. Han, O.E. Femi, F. Kilicaslan, C.U. Jeong, C.H. Baeg, S.J. Hong and J.M. Koo

Abstract

In this study, the mechanical properties of Al-Si alloys was improved by selecting higher Si content and avoiding distortion in Al-Si matrix by adding an extrusion process such that the fabrication processes casting and extrusion were in sequence. Cast billets were extruded at ratios 4:1 and 10:1 to obtained two extruded bars with different processing parameters. The as-extruded samples were characterized and investigated for microstructure and mechanical properties. Optical Microscope was used to examined phase morphologies and microstructures of the extruded Al-Si bars. Mechanical properties were conducted on each sample to study the effectiveness of the additional extrusion process in high Si content Al-Si alloys. The result shows that by increasing the extrusion ratio, the size of the primary Si particle reduces leading to a higher density, better tensile and yield strength compared to the cast billet.