• Journal of Periodontal and Implant Science
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• 제26권1호
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• pp.117-132
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• 1996

The purpose of this study was to evaluate the bacterial adherence on e-PTFE membrane immersed in whole saliva from subjects with different periodontal status. Experiment involved 3 subject groups: 5 persons with healthy periodontium(probing depth below 3mm and no signs of gingival inflammation including bleeding on probing), 10 patients with gingivitis(probing depth below 3mm and apparent signs of gingival inflammation), and 10 patients with advanced periodontitis(probing depth over 7mm and apparent signs of gingival inflammation). Each disease group was included before and after scaling and root planing treatment. After obtaining whole saliva from each subject, e-PTFE membrane(Gore-Tex periodontal membrane : $GTPM^{(R)}$, W.L. Gore & Associates, Flagstaff, USA) specimens were immersed at room temperature in the saliva aliqouts for 1, 3, 7 days. The weight between pre - and post - immersion in saliva was measured with the analytical balance and the difference was recorded. The specimens were processed for SEM observation. The bacterial adherence on the membrane specimens was evaluated using the scanning electron microscope images. The obtained results were as follows : 1. There was no difference in the weight of bacteria adherent to e-PTFE membrane specimens according to the periodontal status and the immersion periods. 2. As the exposure time to saliva increased, the bacterial adherence to the membrane specimen significantly increased in all groups(P<0.005). 3. As the severity of periodontal disease increased, the bacterial adherence to the membrane specimens significantly increased(p<0.001). 4. After scaling and root planing, the bacterial adherence to the membrane specimens significantly decreased in gingivitis and periodontitis patient group(P<0.001). These results suggest that bacterial contamination on exposed barrier membrane surface be reduced through improvement of periodontal status and oral health environment before and after GTR procedure for the successful outcome.

• 농업과학연구
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• 제49권2호
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• pp.259-267
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• 2022

Although pesticides are recognized as necessary substances to improve agricultural production, exposure to pesticides is known to have a direct or indirect adverse effect on the reproductive function of mammals. The present study examines the effects of mancozeb, a well-known fungicide, on the fertility capacity of spermatozoa. Boar spermatozoa exposed to varying concentrations of mancozeb (0.01 - 0.5 µM) were evaluated for motility, motion kinetic parameters, viability, acrosome integrity and the generation of intracellular reactive oxygen species (ROS) after 30 min or 2 hrs of incubation. A significant reduction in the motility of spermatozoa was observed upon exposure to mancozeb. Similarly, there was a significant reduction of the motion kinematics of sperm treated with mancozeb as compared to untreated controls (p < 0.05). The sperm viability percentage and acrosome integrity also showed dose-dependent decreases upon exposure to mancozeb. High concentrations of mancozeb (0.2 - 0.5 µM) induced higher levels of intracellular ROS production, which resulted in the loss of the sperm membrane and decreased sperm motility due to oxidative stress. Taken together, the results here indicate that direct exposure to mancozeb affects the sperm fertility capacity. Hence, careful research that examines the interaction between reproduction and environmental toxins is crucial to prevent fertility disorders in animals.

• Applied Microscopy
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• 제23권2호
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• pp.11-26
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• 1993

This experiment was performed to study the morphological responses of the pigment epithelial cell and the Bruch's membrane of the retina of rat following X-ray irradiation. Male rats were divided into normal and experimental groups. The heads of the rats, under sodium thiopental anesthesia, were exposed to 3,000 rads or 6,000 rads of radiation in a single dose, respectively. The source was a Mitsubishi Linear Accelerator ML-4MV. The target to skin distance was 80cm, and the. dose rate was 200 rads/min. The experimental groups were sacrificed on the 6th hour, 2nd and 6th day after X-ray irradiation. Under anesthesia, 1% glutaraldehyde-1% paraformaldehyde solution(0.1M Millonig's phosphate buffer, pH 7.3) was perfused through the left ventricle and ascending aorta. Pieces of the tissue taken from the posterior region of the retina were fixed in 2.5% glutaraldehyde-1.5% paraformaldehyde(0.1M Millonig's phosphate buffer, pH 7.3) and 1% osmium tetroxide(0.1M Millonig's phosphate buffer, pH7.3), and embedded in araldite mixture. The ultrathin sections contrasted with uranyl acetate and lead citrate were observed with JEM 100 CX-II electron microscope. The results were as follow; 1. The morphological changes of the pigment epithelial cells were not pronounced after exposure to 3,000 rads of X-ray. But on the 6th hour after exposure to 6,000 rads of X-ray, bulging nuclear membrane protruding into the cytoplasm and nuclear chromatin clumped into numerous masses along the nuclear membrane were observed. At the 2nd and 6th day post-irradiation, partial cytolysis or necrosis were seen. 2. The thickness of the Bruch's membrane of the experimental groups were increased in the time and dose range covered by this study, and splitting or diffusing basal laminae of the choriocapillary layer were observed frequently in the experimental group. Above results suggest that large amount(6,000 rads) of head irradiation induce direct hazardous effects on the pigment epitherial cells and Bruch's membrane of the retina of the rat, but pigment epithelial cells are more radioresistant than Bruch's membrane.

• 대한방사선기술학회지:방사선기술과학
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• 제41권5호
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• pp.471-478
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• 2018

Oogenesis process of ovary produces a lot of undifferentiated cells. Especially, the radiation exposure of early immature cells in the process of growth to oocyte causes serious disabilities. This study examined the radiation damage mechanism of undifferentiated cells and organelles in oogenesis process, and the radioprotection after injection of alliin. The ultrastructure after 7Gy X-ray irradiation on the white rat was observed in the experiment. The results is as follows. It was observed that the nucleus membrane of an oogonium was damaged and vacuolated in the several parts after 15 days of irradiation. The damage of mitochondria membrane and flow in cytoplasm after 20 and 30 days was found in the oogonium. After 40 days observation, peroxidation of fat droplets was found and organelles were tangled each other in ovary tissue. The partial damage of nuclear membrane in oogonium past 15 days after injection of alliin was found, but decreased remarkably. Mitochondria, Golgi body, and rough endoplasmic reticulum were also clearly observed, therefore, radioprotection effects in alliin was confirmed partially.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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• pp.75-75
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• 2003

We report upon the cytotoxic activity of the ginseng saponin metabolite, Compound K (20-O-D-glucopyranosyl-20(S)-protopanaxadiol, IH90l) on various human leukemia cell lines. Compound K had most effect on U937, a human monocytic leukemia cell line, which on treatment showed; a exposure of phosphatidylserine from the inner cell membrane to the outer cell membrane, the formation of apoptotic bodies and DNA fragmentation, - characteristics of apoptosis. Compound K induced apoptosis by up-regulating Bax, disrupting the mitochondria membrane potential, and by activating caspase 9 and caspase 3. Therefore, we suggest that Compound K inhibit U937 cell growth by inducing apoptosis through the up-regulation of Bax and caspase activation.

• 한국미생물·생명공학회지
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• 제25권3호
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• pp.240-247
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• 1997

Bacillary is the most common form of H. pylori observed during human infection. However, it is known that the morphology change of H. pylori from bacillary to coccoid can be occurred with a response to the environmental stresses such as the nutrient depletion, accumulation of toxic metabolites, pH alteration, and exposure to antimicrobial agents. The coccoid form of H. pylori, which is viable but non-culturable in vitro, seems to be the major cause of antibiotic resistancy and high reinfectability of H. pylori. In this regard, we studied the environmental factors that can induce the morphological change in vitro of H. pylori, and the change of fatty acid composition of plasma membrane. The morphological change from bacillary to coccoid could be observed with the depletion of nutrients, pH variation and reactive oxygen species added in the culture media. This morphologic conversion was paralleled by a dramatic decrease in unsaturated fatty acids and an increase in saturated fattv acids of plasma membrane. The change in composition of membrane fatty acid seems to be a kind of protection mechanism of H. pylori against these environmental stresses.

• Journal of Periodontal and Implant Science
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• 제45권6호
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• pp.229-237
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• 2015

Purpose: The aim of this study was to determine the clinical feasibility of using dehydrothermally cross-linked collagen membrane (DCM) for bone regeneration around peri-implant dehiscence defects, and compare it with non-cross-linked native collagen membrane (NCM). Methods: Dehiscence defects were investigated in twenty-eight patients. Defect width and height were measured by periodontal probe immediately following implant placement (baseline) and 16 weeks afterward. Membrane manipulation and maintenance were clinically assessed by means of the visual analogue scale score at baseline. Changes in horizontal thickness at 1 mm, 2 mm, and 3 mm below the top of the implant platform and the average bone density were assessed by cone-beam computed tomography at 16 weeks. Degradation of membrane was histologically observed in the soft tissue around the implant prior to re-entry surgery. Results: Five defect sites (two sites in the NCM group and three sites in the DCM group) showed soft-tissue dehiscence defects and membrane exposure during the early healing period, but there were no symptoms or signs of severe complications during the experimental postoperative period. Significant clinical and radiological improvements were found in all parameters with both types of collagen membrane. Partially resorbed membrane leaflets were only observed histologically in the DCM group. Conclusions: These findings suggest that, compared with NCM, DCM has a similar clinical expediency and possesses more stable maintenance properties. Therefore, it could be used effectively in guided bone regeneration around dehiscence-type defects.

• 대한기관식도과학회지
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• 제6권1호
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• pp.29-37
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• 2000

Background and Objectives : The concentration of sulfur dioxide($SO_2$) gas in the ambient air appears increasing in the industry and urban area day by day. It was known that $SO_2$ is noxious gas. $SO_2$ can be irritating to the eyes, nose, throat, upper respiratory tract and skin. It produces sulfurous acid on contact with water and is extremely irritating to the nasopharynx and respiratory tract. Laminin is a family of extracellular matrix glycoproteins localized in the basement membrane that separates epithelial cells from the underlying stroma. The biological activities of laminin are to promote cell migration, wound healing, growth and differentiation. Meterials and Methods : The histologic changes and the expression of laminin in tracheal mucosa sacrificed at every weeks (to 7 weeks) after continued $SO_2$ exposure of 250ppm for 30 minutes a day were studied in rats. Results : Pathologic tissue was formed at the tracheal mucosa and the underlying tissue by the infiltration of monocytes and epithelium was transformed to the single cell layered epithelium above 5 weeks after exposure. At the 6 weeks after exposure, epithelial cells were partially lost and epithelial cell layer was transformed to be leaf-shaped. Submucosal tissue was transformed to be lymphatic tissue. An intense positive staining for laminin was found in apical cytoplasm and lateral surface of the normal epithelial cells and basement membrane but at the 5 and 6 weeks after exposure, laminin activity was decreased to the moderate activity. At the 7 weeks after exposure, laminin activity was decreased to the weak activity. Conclusion : Our finding suggests that $SO_2$ makes histologic damage on the tracheal mucosa and decreases immunoreactivity for laminin. Longer duration of the exposure of $SO_2$ makes more histologic damage on the tracheal mucosa and decreases immunoreactivity for laminin.

• Membrane and Water Treatment
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• 제13권1호
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• pp.21-28
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• 2022

The use of plastics in our everyday lives have been drastically increased during the last few decades. However with the usage of commercial plastic products there is a possibility of microplastic consumption, due to the fragmentation of the products. Additionally, the potential for microplastic ingestion may also be increased by using damaged products. Hence, the current study was conducted to understand the potential release of micro/nano plastics and organic matter from damaged teabags. To check the leakage tendency, the amount of damage to the tea bags from 1-10 cm were tested along with temperatures of 25-70℃, and exposure times from 5 min to 1 hr was tested. Release of fibrous micro/nanoplastics, and organic leachate from the damaged teabags were observed to understand the outflow conditions. Results showed that with the increased degree of damage, temperature, and exposure time increased the release of fiberous matter, where the increase of temperature, and exposure time increased organic leachate. Additional analysis confirmed the leachate of nylon polymers into the heated water.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.484.2-484.2
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• 2014

There are many efforts to improving the power conversion efficiencies (PCEs) of dye-sensitized solar cells (DSCs). Although DSCs have a low production cost, their low PCE and low thermal stability have limited commercial applications. This study describes the preparation of a novel multifunctional polymer gel electrolyte in which a cross-linking polymerization reaction is used to encapsulate $TiO_2$ nanoparticles toward improving the power conversion efficiency and long-term stability of a quasi-solid state DSC. A series of liquid junction dye-sensitized solar cells (DSCs) was fabricated based on polymer membrane encapsulated dye-sensitized $TiO_2$ nanoparticles, prepared using a surface-induced cross-linking polymerization reaction, to investigate the dependence of the solar cell performance on the encapsulating membrane layer thickness. The ion conductivity decreased as the membrane thickness increased; however, the long term-stability of the devices improved with increasing membrane thickness. Nanoparticles encapsulated in a thick membrane (ca. 37 nm), obtained using a 90 min polymerization time, exhibited excellent pore filling among $TiO_2$ particles. This nanoparticle layer was used to fabricate a thin-layered, quasi-solid state DSC. The thick membrane prevented short-circuit paths from forming between the counter and the $TiO_2$ electrode, thereby reducing the minimum necessary electrode separation distance. The quasi-solid state DSC yielded a high power conversion efficiency (7.6/8.1%) and excellent stability during heating at $65^{\circ}C$ over 30 days. These performance characteristics were superior to those obtained from a conventional DSC (7.5/3.5%) prepared using a $TiO_2$ active layer with the same thickness. The reduced electrode separation distance shortened the charge transport pathways, which compensated for the reduced ion conductivity in the polymer gel electrolyte. Excellent pore filling on the $TiO_2$ particles minimized the exposure of the dye to the liquid and reduced dye detachment.