• Journal of Periodontal and Implant Science
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• 제39권2호
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• pp.129-138
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• 2009

Purpose: This study was designed to compare the bond regeneratiom effects of treatment using silk fibroin membrane ( Nanogide-S$^{(R)}$ ) resorbable barrier with control group treated by polyactic acid / polylacticglycolic acid membrane(Biomesh$^{(R)}$ ) Methods: 44 severe bone loss on extraction socket from 44 patients were used in this study. In experimental group 22 sites of them were treated by silk fibrin membrane as and the other 22 sites were treated by polyactic acid/ polylacticglycolic acid membrane as a control group. Clinical parameters including recovered bone width, length and radiographic parameter of vertical length were evlauated at base line and 3 months after surgery. Results: 1) Severe bone width, length was significantlly decreased in two group. 2) Bone width, length was significantlly decreased in two group. 3) Decreased bone width, length and radiographic examination differences between group. Conclusions: On the basis of these results, silk fibrin resorbable membrane has similar bone regeneration ability to polyactic acid / polylacticglycolic acid membrane in guided bone regeneration for severe bone loss defect on extraction socket.

• 한국의류산업학회지
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• 제15권2호
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• pp.302-308
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• 2013

This study is a preliminary investigation of the influence of surface characteristics of substrates on detergency of particulate soil. The surface of PET film was modified with NaOH and NaOH+ethylene diamine on different times. The surface morphology of the film was scanned by AFM and surface energies were calculated from measured contact angles between several solutions and film based on the geometric mean and a Lewis acid base method. The surface morphology of PET film treated with NaOH and NaOH+ethylene diamine became more etched, and the surface area, surface roughness and the coefficient of friction of film increased with treatment of NaOH and NaOH+ethylene diamine. The contact angle of film treated with NaOH and NaOH+ethylene diamine decreased in water and surfactant solution; in addition, the surface energy increased was largely attributed to the increased portion on the polar surface energy of film. However, the effect of the diamine addition to the NaOH treatment solution on surface characteristics of PET film was insignificant.

• 폴리머
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• 제25권4호
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• pp.587-593
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• 2001

본 연구에서는 red mud(RM)를 0.1, 1, 그리고 5M 의 H$_3PO_4$ 용액으로 화학적 표면처리하여 에폭시/RM 나노복합재료를 제조하였으며, RM 표면의 pH, 표면 산-염기도, 표면적, 그리고 기공도를 이용하여 표면처리에 의한 영향을 분석하였다. 또한, 임계응력 세기인자(K$_{IC}$)를 통하여 제조된 복합재료의 기계적 계면물성을 조사하였다. 실험결과로부터, 표면처리에 의한 RM의 표면은 hydroxyl 등의 산성관능기 그룹의 생성과 금속산화물의 반응으로 인하여 표면 산도가 증가하고, 미세기공 및 중기공 구조가 발달하여 비표면적이 증가되었다. K(IC)를 이용한 RM의 기계적 계면성질은 비표면적이 증가함과 동시에 표면산도가 증가함으로 염기성 매트릭스와의 계면결합력이 증대되어 순수 에폭시와 처리되지 않은 에폭시/RM 복합재료보다 더 우수한 기계적 계면물성을 나타내었다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권7호
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• pp.1025-1029
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• 2003

The effect studied was that of the feeding of shrimp by-product meal, as a source of eicosapentaenoic and docosahexaenoic acid, on growth performance and fatty acid composition of adipose tissue in growing pigs kept on small holdings in Central Vietnam. Shrimp by-product meal was exchanged with ruminant meal so that the diets contained either 0, 10 or 20% shrimp byproduct meal in the dry matter. The diets were fed on 6 different small-holder farms. The farmers fed a base diet according to their personal choice, but were instructed as to the use of shrimp by-product and ruminant meal. The diets were fed to the pigs from 70 to 126 days of age. There were three animals per treatment group per farm. The diets without and with 20% shrimp by-product meal on average contained 0.01 and 0.14 g docosahexaenoic acid/MJ of metabolisable energy (ME). Due to the higher contents of ash and crude fiber, the shrimp by-product meal containing diets had lower energy densities than the control diets. Eicosapentaenoic acid was not detectable in adipose tissue; the content of docosahexaenoic acid was generally increased after consumption of shrimp by-product meal. In spite of the concurrent high intakes of ash and crude fiber, the feeding of shrimp by-product meal had a general stimulatory effect on growth performance of the growing pigs. The intake of docosahexaenoic acid or its content in adipose tissue was not related with average daily gain. It is suggested that shrimp by-product meal may contain an unknown growth enhancing factor.

• 한국의류학회지
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• 제36권10호
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• pp.1117-1124
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• 2012

This study was a preliminary study to investigate the influence of surface morphology and characteristics on the self-cleaning of substrates. PI film was treated by $O_2$ plasma to modify the surface; in addition, AFM and Fe-SEM were employed to examine the morphological changes induced on a PI film treated by $O_2$ plasma and surface energies calculated from measured contact angles between several solutions and PI film based on the geometric mean and a Lewis acid base method. The surface roughness of PI film treated by $O_2$ plasma increased with the duration of the $O_2$ plasma on PI film due to the increased surface etching. The contact angle of film treated by $O_2$ plasma decreased with the increased treatment time in water and surfactant solution; in addition, the surface energy increased with the increased treatment times largely attributed to the increased portion on the polar surface energy of PI film. The coefficient of the correlation between surface roughness and surface polarity such as contact angle and surface energy was below 0.35; however, it was over 0.99 for the contact angle and surface energy.

• 한국환경과학회지
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• 제20권6호
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• pp.767-773
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• 2011

The objectives of this research are to investigate the proper coagulation conditions which are a type and doses of coagulants, mixing conditions (velocity gradients and mixing times), pH and so on through Jar-test, to evaluate the flux variations, permeate, backwashing according to characteristics of pretreatment of the wastewater by means of MF membranes for river maintenance water reuse. The effluent water from B-city K-sewage treatment plant are used for this research. Turbidity and suspended solids(SS) are 14.2 NTU and 10.4 mg/L respectively. This condition causes fouling for membrane process. The flux decline could be reduced when coagulation pretreatment was carried out. Optimal coagulations PAC which are commonly used in the sewage treatment plant was observed in this research. The results indicate that an optimal coagulation dose and pH are 80 ppm and pH of 7 respectively, but coagulation efficiency was lower at strong acid or strong base. Results showed that continuous and steady operations in membrane separation process by means of the effective removal of organic matter and turbidity with coagulation pretreatment of sewage secondary effluent were achieved.

• 대한환경공학회지
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• 제28권11호
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• pp.1135-1140
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• 2006

국내 정수장에서 염소소독시 발생하는 소독부산물인 트리할로메탄(THMs), 할로아세틱에시드(HAAs)의 발생농도와 각각의 종별 분포현황을 조사하였다. 조사대상은 일반적인 정수처리공정으로 구성된 한강, 금강, 섬진강, 낙동강 수계의 1개 정수장씩 총 4개소였다. THMs의 발생농도는 평균 26.9 ppb, 최대 46.7 ppb, 최소 11.0 ppb였으며, $HAA_5$의 발생농도는 평균 25.4 ppb, 최대 57.1 ppb, 최소 9.7 ppb였다. 계절적으로는 동절기에 농도가 낮았고 하절기에 높았다. THMs의 종별 분포를 조사한 결과 클로로포름의 비율이 평균 77%로 가장 높았고 다음으로는 브로모디클로로메탄(20%)이 높게 검출되었으며, 브로모포름의 농도는 정량한계 미만이었다. $HAA_5$의 경우 디클로로아세틱에시드(DCAA)와 트리클로로아세틱에시드(TCAA)의 합이 $HAA_5$의 97%를 차지하는 것으로 조사되었다. 그러나 한강수계의 경우는 이 비율이 평균 90%로 다소 낮았으며, 특히 겨울철에 비율이 가장 낮았다. 한편, 하절기를 제외하고는 DCAA가 TCAA보다 높은 것으로 조사되었다.

• Tribology and Lubricants
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• 제16권5호
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• pp.332-340
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• 2000

The reduction of sulfur content in the diesel fuel has caused the poor lubricity of diesel fuel in the distributor type injection pumps of diesel engines that use the diesel for lubrication of their moving parts. To investigate the reason for poor lubricity of low sulfur diesel fuels, the wear scar diameters by HFRR (High Frequency Reciprocating Rig) were measured on the diesel fuels from Korean markets and the results were compared with their physical and chemical properties. Also, the lubricity change and the improvement effects on lubricity additives for the ultra low sulfur diesel fuel, were made experimentally, that will be regulated to a maximum of 0.005 wt% from about 2005 were evaluated. As a result, a good correlation was found between the wear scar diameter and the polyaromatic compound which includes heterocyclic compound in the diesel fuel. It was also found that the content of polyaromatic compound including heterocyclic compound was affected by the amount of desulfurization treatment fraction. And the lubricity additives with ester base were more effective than that with acid base on the ultra low sulfur diesel fuel. Therefore, it is suggested that the factors affecting the lubricity stated above should be taken into account to improve the lubricity property of the diesel fuel in the refining process.

• Asian-Australasian Journal of Animal Sciences
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• 제33권7호
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• pp.1068-1076
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• 2020

Objective: In the present study, we determined efficiency of incorporating caffeine, melatonin or omega-3 polyunsaturated fatty acid in the diluent on mitigating consequences of (a) liquid chilled- and (b) cryo-storage of ram spermatozoa. Methods: In the first experiment, ejaculates (n = 30) were collected from 5 adult rams and were pooled, diluted (1:10) with Tris-citric acid (base diluent) and were split into 4 aliquots assigned for: control (untreated), caffeine (0.1 mM), melatonin (0.3 mM) or omega-3 fatty acids (0.3 mM) (T₀). The diluted specimens were stored at 4℃ for 48 h, during which sperm physical and cytological properties were evaluated along with oxidative stress indices (T₂₄, T₄₈). In the second experiment, 15 ejaculates (3 per male) were pooled, diluted with glycerolized base diluent (4% glycerol, v/v) and were split corresponding to the same previous treatment groups before being processed for cryopreservation. Post-thaw physical and kinematic sperm properties were assessed by a computer-assisted sperm analysis system. Results: The results clarified superiority of both melatonin and omega-3 supplementation on maintaining (p<0.05) sperm properties, while reducing (p<0.05) lipid peroxidase reaction and enzymatic activities of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase in preservation medium, compared to caffeine either during liquid-chilled storage or cryopreservation of spermatozoa. Conclusion: Melatonin and omega-3 are regarded efficient alternatives to caffeine when processing ram spermatozoa for application of artificial insemination or in vitro fertilization.

• 약학회지
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• 제45권1호
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• pp.46-54
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• 2001

Protein carboxyl Ο-methylation is a kind of enzymatic reaction producing carboxyl methylester catalyzed by protein carboxyl Ο-methyltransferases at the carboxyl group of amino acid residues in polypeptide. Since the finding of carboxyl methylesterl many studies have been focused on the under-standing of biological functions in eukaryotes but still not clear except for roles in Ras attachment to membrane and protein repair. In this study, we investigated the protein carboxyl methylation in porcine liver and testis in respect of identification and characterization of carboxyl methylesters and natural proteinous substrates using pH stability of the esters and electrophoresis under acidic and basic conditions. We detected several kinds of methyl esters, 3 kinds each in cytosolic fractions from liver and testis. Under the treatment of strong acid and base, the ratio between base-stable substrates and unstable ones in liver (4 : 6) was different from the ratio obtained in testis (6 : 4). The methyl accepting capacities were affected by enzymatic proteolysis between the range of 55 to 65% in liver and of 35 to 45% in testis. Separation of the methylated proteins by acidic electrophoresis in the presence of urea and SDS revealed distinctively natural substrates of 26, 33 and 80 kD in the cytosol from liver and of 14, 25, 32 and 86 kD from testis. Most of the labelling, however were lost following electrophoresis under moderate alkaline condition, except for molecules of newly detected 7 and 17 kD in livers and 15, 29, 40 and 80 kD in testis. From these results, it was proposed that protein carboxyl Ο-methylation in each organs may be catalyzed by different classes of protein carboxyl Ο-methyltransferases. In addition, it is suggested that the protein carboxyl methylation in liver and testis may have different patterns in respect of natural substrates.