• Korean Journal of Poultry Science
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• v.33 no.3
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• pp.181-188
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• 2006

Changes in the fine structure of testicular Leydig cell from hatching to adulthood were studied in Korean native chickens of 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 21, 24, 28, 32, 44, 52 and 64 weeks (n=13 chickens per group) of age. The objective of this study were to elucidate Leydig cell ultrastructure during testicular development. Testes of chickens were fixed by whole body perfusion using a fixative containing 2.5% glutaraldehyde in cacodylate buffer, processed and embedded in Epon-araldite. Using $1{\mu}m$ sections stained with methylene blue-azure II, qualitative and quantitative(stereological) morphological studies were performed. The ultrastructural changes of the Leydig cell were investigated by ultrathin section with the transmission electron microscope. The stages of the Leydig cell development described focus on mitochondria, endoplasmic reticulum, and lipid droplets which are involved in androgens as fullows. 1) Approaching puberty. The closely packed Leydig cells and sparse intercellular space. The nucleus occupied a large portion of the Leydig cell volume. The population of Leydig cells contained two types of cells that differed in the appearance of their nuclei which were either highly electron-opaque or relatively electron-lucid. The cytoplasm was characterized by large amounts of lipid droplets, relatively few spherical mitochondria, and sparse smooth endoplasmic reticulum. 2) Puberty to adult. The Leydig cells which display features compatible with significant androgen synthesis: large volume of cytoplasm containing extended smooth endoplasmic reticulum, abundant mitochondria, and reduction of lipid droplets.

• Development and Reproduction
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• v.14 no.4
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• pp.269-279
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• 2010

Some characteristics of germ cell differntiations and the function of accessory cells during spermatogenesis, and mature sperm ultrastructure in male Protothaca (N.) jedoensis were investigated by transmission electron microscope observations. The morphology of the spermatozoa of this species has a primitive type and is similar to those of other species in the subclass Heterodonta. Accessory cells, which are connected to adjacent germ cells, are involved in the supplying of the nutrients for germ cell development. The morphologies of the sperm nucleus and the acrosome of this species are the cylindrical type and cap shape, respectively. Spermatozoa are approximately $46{\sim}50{\mu}m$ in length including a long sperm nucleus (about $2.44{\mu}m$ in length), an acrosome (about $0.45{\mu}m$ in length), and tail flagellum (about $42{\sim}46{\mu}m$). The axoneme of the sperm tail shows a 9+2 structure. As some characteristics of the acrosomal vesicle structures, the basal and lateral parts of basal rings show electron opaque part (region), while the anterior apex part of the acrosomal vesicle shows electron lucent part (region). These characteristics of the acrosomal vesicle were found in the family Veneridae and other several families in the subclass Heterodonta. These common characteristics of the acrosomal vesicle in the subclass Heterodonta can be used for phylogenetic and systematic analysis as a taxonomic key or a significant tool. The number of mitochondria in the midpiece of the sperm of this species are four, as one of common characteristics appear in most species in the family Veneridae and other families in the subclass Heterodonta. However, exceptionally, only three species in Veneridae of the subclass Heterodonta contain 5 mitochondria. The number of mitochondria in the sperm midpiece can be used for the taxonomic analysis of the family or superfamily levels as a systematic key or an important tool.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.3
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• pp.122-126
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• 2003

In this study, $Zn_{0.86}Mn_{0.14}$Te epilayer of 0.7 $\mu\textrm{m}$-thickness was grown on GaAs(100) substrate by using hot wallepitaxy. GaAs(100) substrate was removed from $Zn_{0.86}Mn_{0.14}$Teepilayer by the selective etching solution. The crystal structure and the lattice constant of only Z $n_{0.86}$ M $n_{0.14}$Te epilayer were investigated to be zincblende and 6.140 $\AA$ from X-ray diffraction pattern, respectively. Mn composition x of $Zn_{1-x}Mn_x$Te epilayer was found to be 0.14 using this lattice constant and Vegard's law. The crystal quality of the epilayer was confirmed to be very good due to 256 arcsec-full-width at half-maximum of the double crystal rocking curve. The absorption spectra from the transmission ones were obtained to measure the band gap energy of $Zn_{0.86}Mn_{0.14}$Te epilayer from 300 K to 10 K. With the decreasing temperature,. strong absorption regions in the absorption spectra were shifted to higher energy side and the absorption peak meaning the free exciton formation appeared near the absorption edge. The band gap energy values of $Zn_{0.86}Mn_{0.14}$Te epilayer at 0 K and 300 K were found to be almost 2.4947 eV and 2.330 eV from the temperature dependence of the free exciton peak position energy of $Zn_{0.86}Mn_{0.14}$Te epilayer, respectively. The free exciton peak position energy of $Zn_{0.86}Mn_{0.14}$Te epilayer without GaAs substrate was larger 15.4 meV than photoluminescence peak position energy at 10 K. This energy difference between two peaks was analysed to be Stokes shift.

• Journal of Bio-Environment Control
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• v.23 no.2
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• pp.148-157
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• 2014

The purpose of this study was to investigate greenhouse maintenance by farms by looking into greenhouses across the nation for greenhouse specification, disaster-resistance greenhouse construction, types and degree of damage due to natural disasters, pre-inspection in case of typhoon or heavy snow forecast, and fire-fighting facilities to prevent a fire. The findings were summarized as follows: as for greenhouse specification, the highest proportion of them were 90 m or longer both in single- and multi-span greenhouses in terms of length; 8 m or wider and 7.0~7.9 m in single- and multi-span greenhouses, respectively, in terms of width; 1.5~1.9 m and 2.0~2.9 m in single-and multi-span greenhouses, respectively, in terms of height; and 3.0~3.9 m and 6 m in single- and multi-span greenhouses, respectively, in terms of diameter. As for disaster-resistance greenhouses, farmers were reluctant to install such greenhouses. The low distribution of disaster-resistance greenhouses was attributed to the greenhouses built dependent on the old practice, the greenhouses already completed, and relatively high construction costs. As for damage by natural disasters, greenhouses were subject to more damage by typhoons than heavy snow. They mainly inspected the ceiling and side windows, entrances, and fixation bands for covering materials in case of typhoon forecast and the heating devices in case of heavy snow forecast. As for repair methods for greenhouse pipe corrosion, they preferred partial replacement to painting and did not use stiffeners for structures to prevent a natural disaster in most cases. As for the maintenance of greenhouse covering materials, most farmers inspected their sealing property but did not clean the coverings for light transmission. The destruction of structural materials can be prevented by eliminating greenhouse covering materials during a typhoon, but they were not able to do so because of the covering material replacement costs and the crops they were growing. The study also examined whether greenhouse farms had fire-fighting facilities to prevent a fire and found that they lacked the perception of greenhouse fire prevention to a great degree.

• Journal of the Korean Applied Science and Technology
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• v.30 no.1
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• pp.116-126
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• 2013

Glycol ethers are a group of solvents based on alkyl ethers of ethylene glycol commonly used in paints. These solvents typically have a higher boiling point, together with the favorable solvent properties of lower-molecular weight ethers and alcohols. The word "Glycol ethers" was registered as a United States trademark by Union Carbide Corp. Typically, glycol ethers are found in pharmaceuticals, sunscreens, cosmetics, inks, dyes and water based paints. On the other hand, glycol ethers are used in degreasers, cleaners, aerosol paints and adhesives. Most glycol ethers are relatively water soluble, biodegradable and only a few are considered toxic. Therefore, they are unlikely to pose an adverse risk to the environment. Recent study suggests that occupational exposure to glycol ethers is related to low motile sperm count in men, but the finding has been disputed by others. In this study, skin permeation of 3 types glycol ethers were studied in vitro using matrix such as solvent and detergent. The absorption of glycol ethers[methyl glycol ethers(MC), ethyl glycol ethers(EC) and butyl glycol ethers(BC)] has been measured in vitro through rat skin. Epidermal membranes were set up in Franz diffusion cells and their permeability to PBS measured to establish the integrity of the skin before the glycol ethers were applied to the epidermal surface. Absorption rates for each glycol ethers were determined and permeability assessment made to quantify any irreversible alterations in barrier function due to contact with the esters. Types of glycol ethers in vitro experimental results on MC> EC> BC quickly appeared in the following order: skin permeation was beneficial to the skin permeation small molecular weight, the difference in chemical structure, such as hydrophilic, because with the partition coefficient and solubility mechanisms and passive diffusion to increase the speed at which transmission is considered.

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1285-1297
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• 2020

In this study, we report the results of a study on the clinical evaluation of wrinkle improvement by developing a method for liposome of high-purity Centella asiatica extract used in pharmaceuticals and cosmetics, and a cream using the same. In order to make Centellasome-10EX stabilizing centella asiatica extract in liposome lamella vesicle, it could be completed using 5% hydrogenated lecithin and 2% sucrose distearate. The appearance of Centellasome-10EX was a creamy form of low viscosity, the color was pale yellow, and the odor had the inherent odor of the raw material. The pH was about 6.12, the specific gravity was 1.09, and the acid value was about 0.35. The content of the main constituents of centella asiatica extract contained in the liposome vesicle contains 10,800 ppm of asiatic acid, 10,900 ppm of asiaticoside, 6,000 ppm of madecasic acid, and 1,600 ppm of madecassoside, and long-term storage. There was no discoloration even at the time, and it was found that the main component remained stable thermodynamically. To mechanistically analyze the structure of the liposome vesicle of Centellasome-10EX, as a result of observation with a transmission electron microscope (Cryo-TEM), the multilayer vesicles are formed and filled with moisture, and there are 10 to 60 multilayers around it. It was confirmed that the liposome lamella vesicle was formed. As a clinical trial (in-vivo) test, the moisturizing effect of centellasome cream after application for 5 weeks was 28.3%, which was significantly increased compared to placebo. The skin elasticity effect was 13.6%, which significantly increased the moisturizing power than the placebo. The effect of improving fine wrinkles around the eyes was improved by 23.52% compared to placebo cream. Through the results of this study, it was possible to study the formulation and manufacturing method for encapsulation and stabilization of the developed Centellasome-10EX in the liposome vesicle. It is expected that the results obtained through clinical research on the wrinkle improvement effect of the cream using this can be widely used to study skin science in the cosmetic industry and to develop high-quality cosmetics with high efficacy.

• Research in Plant Disease
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• v.11 no.2
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• pp.128-134
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• 2005

This study was conducted to elucidate effect of environmental factors on the development of white rot. In order to identify the causal agents causing white rot of Allium crops, we compared DNA profiles of a representative isolate, Sclerotium cepivorum, introduced from foreign country with Korean isolates using UP-PCR. As a result, Sclerotium isolates forming round-shaped sclerotia were identified as Sclerotium cepivorum pertaining in UP-PCR b group and Sclerotium isolates farming anamorphic-shaped sclerotia presumed to be a novel species of Sclerotium based on DNA profiles of UP-PCR. There was a big difference in DNA band pattern between two species of Sclerotium isolated in Korea. Electron micrographs of scanning electron microscope and transmission electron microscope showed morphological differences in sclerotial surface structure and rind layers between two species of Sclerotium. There were more wrinkles and pore spaces on sclerotial surface of Sclerotium sp. forming anamorphic-shaped sclerotia than that of Sclerotium cepivorum forming round-shaped sclerotia. Both of two white rot pathogens grew well at the temperature range of $10-25^{\circ}C$ with optimal temperature of $20^{\circ}C$. Sclerotia of the two pathogens were well formed at $20^{\circ}C$ and well germinated at the temperature range of $20-24^{\circ}C$, Effect of pre-incubation of sclerotia on destruction of sclerotial dormancy of two pathogens was evaluated through storing sclerotia under different temperature condition. The sclerotia of the two pathogens showed an increased capacity to germinate on potato dextroise agar when the sclerotia were incubated for 7 days at $10^{\circ}C$ after pre-treatment at $35^{\circ}C$ for 7 days. At that time, germination rate of Sclerotium sp. and 5. cepivorum was $100\%\;and\;70\%$, respectively. Flooding period and treatment temperature had an effect on sclerotial survival rate of the two pathogens. As flooding period and treatment temperature increased, sclerotial germination rate of the two pathogens decreased. It was confirmed that soil humidity played an important role on development of white rot. It was the highest disease incidence of garlic white rot when garlic were sown at potted soils infested with the two pathogens and adjusted soil humidity to $15\%$ (field moisture capacity, about -300 mb). As soil humidity increase or decrease based on $15\%$ of soil humidity, disease incidence decreased move and more.

• Applied Microscopy
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• v.41 no.4
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• pp.277-284
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• 2011

This study was conducted to determine the antiseptic effect of stabilized chlorine dioxide (S-$ClO_2$) on muscle tissue of rats. Skeletal muscle of 8-week old Sprague-Dawley rats was used. Light and transmission electron microscopic findings were observed in the control group, which was not treated with stabilized chlorine dioxide, and in the experimental group, which was treated with a stabilized chlorine dioxide powder in aqueous solution. According to the LM and TEM observations, the day 1 control group showed the initiation of endomysium collapse resulting in an unclear boundary of muscle fibers, and partial collapse of the mitochondrial membranes. All endomysium had collapsed, and bacteria were observed among muscle fibers in the day 2 and later groups. Shapes of muscles were not distinguishable in day 3 or later groups. In contrast, the day 1 and 3 experimental groups revealed detailed structure of typical muscles, but partial collapse of the mitochondrial membranes was observed in the day 3 and later groups. Subsequently, connective tissues collapsed and structures in the shape of concentric circles were observed. In summary, the day 1 control group showed the initial collapse of tissues, and shapes were not distinguishable in the day 3 and later groups because most of the tissues had collapsed. In contrast, the day 3 experimental group showed partial collapse, but the overall shapes of muscles were maintained as time went on, confirming the antiseptic effect of stabilized chlorine dioxide on muscles.

• Korean Journal of Plant Resources
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• v.8 no.3
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• pp.325-334
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• 1995

The early senescence mutant induced from Gihobyeo by $\gamma-ray$ irradiation was determined. The mutated gene expression was identified with comparing the characteristic of original cultivar. The mutant had so similar the morphological characteristics to original cultivar that it couldn't be distinguished until senescence occurred at about 20 days after heading. Suddenly yellow leaves were observed within a few days due to great decreases in total chlorophyll and various carotenoid contents. Transmission electron microscopy showed the formation of starch granules, distortion of fine structure of leaf cell organelles, especially grana structures, and the decrease in grain filled after senescence occurred. But banding patterns of total proteins and isozymes have not show any differences, The early senescence mutant will be very useful for study material not only on physiological and biochemical properties of plant senescence but also on gene expression regulating senescence which gives great influence on yield potential and its stability.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.3
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• pp.115-120
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• 2016

$CeO_2$ is used as a co-catalyst with $TiO_2$ to improve the catalytic activity of $MnO_x$ and characterization of nano-sized powder is identified with de-NOx efficiency. A comparison between $MnO_x-CeO_2/TiO_2$ and single $CeO_2$ was conducted in terms of microstructural analysis to observe the behavior of $CeO_2$ in the ternary catalyst. The $MnO_x-CeO_2/TiO_2$ catalyst was synthesized by sol-gel method and the average particle size of the single $CeO_2$ is about $285{\mu}m$ due to the low thermal stability, whereas the particle size $MnO_x-CeO_2/TiO_2$ is about 130 nm. The strong interaction between Ce and Ti was identified through the EDS mapping by transmission electron microscopy (TEM). The improvement about 20 % of $de-NO_x$ efficiency is observed in the low-temperature ($150^{\circ}C{\sim}250^{\circ}C$) and vigorous oxygen exchange by well-dispersed $CeO_2$ is the reason of catalytic activity improvement.