• Restorative Dentistry and Endodontics
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• 제16권2호
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• pp.33-42
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• 1991

The purpose of this study was to evaluate the sealing properties of the temporary filling materials used in endodontic treatment Access cavities were prepared in 135 extracted human molar teeth. Then, cotton pellets were placed in the pulp chamber until the depth of 5 mm for the temporary filling materials; Caviton, zine oxide-eugenol, double sealing (A) (stopping 15 mm + zinc oxide - eugenol, 3.5mm ) double sealing (B) (stopping 3.0 mm + zinc oxide - eugenol 2.0 mm) and gutta percha stopping. After filling the materials, the teeth were immersed in 1 % methylene blue solutions for 3 days, 1 week and 2 weeks. Then thermal cycling was performed at the temperature of $60^{\circ}C$ and $4^{\circ}C$, followed by longitudinal sections on the center of tooth. Finally, staining on the cotton pellet was evaluated. The following results were obtained. 1. Stopping showed lower marginal sealing quality than Caviton, zinc oxide - eugenol and double sealing. 2. In 1 week group, Caviton showed higher marginal sealing quality than zinc oxide-eugenol, double sealing and stopping. 3. Caviton and double sealing (B) showed a great decrease in marginal sealing quality with the increse of time. 4. Caviton had high marginal sealing quality in 3 day group and 1 week group, but in 2 week group, Caviton showed a great decrease. 5. Double sealing (B) showed fairly high marginal sealing quality in 3 day group, but decreased greatly after 1 week on.

• The Plant Pathology Journal
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• 제36권5호
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• pp.476-490
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• 2020

The parasitic weed, Orobanche crenata, is one of the most devastating constraint for faba bean production in Mediterranean regions. Plant host defense induction was reported as one of the most appropriate control methods in many crops. The aim of this study was to elucidate the effect of salicylic acid (SA) and indole acetic acid (IAA) on the induction of faba bean resistance to O. crenata under the field and controlled experimental conditions. Both hormones were tested on two contrasting faba bean genotypes: Giza 843 (partially resistant to O. crenata) and Lobab (susceptible) at three different application methods (seed soaking, foliar spray, and the combination of both seed soaking and foliar spray). Soaking seeds in SA or IAA provided the highest protection levels reaching ~75% compared to the untreated control plants. Both elicitors limited the chlorophyll content decrease caused by O. crenata infestation and increased phenolic compound production in host plants. Phenylalanine ammonia lyase, peroxidase, and polyphenol oxidase activities were stimulated in the host plant roots especially in the susceptible genotype Lobab. The magnitude of induction was more obvious in infested than in non-infested plants. Histological study revealed that both SA and IAA decreased the number of attached O. crenata spikes which could be related to specific defense responses in the host plant roots.

• 대한약리학회지
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• 제17권2호
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• pp.31-36
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• 1981

Heavy metals which are present as trace elements in human body have been known to modify various enzymatic reaction. These metals can be essential or non-essential. Zinc, copper and calcium are essential in maintaining some biological processes, whereas non-essential metals such as cadmium, lead and mercury produce accumulatve toxic effect. Cadmium accumulated in pancreas can cause toxicity and damage of pancreatic cells, thereby influencing CHO metabolism. Lead compounds are known to produce toxic effects on the kidney, digestive system and brain fellowed by inhibition of activity of ${\rho}-aminolevulinic$ acid and biosynthesis of hemoproteins and cytochrome. Evidence has been accumulated that zinc not only acts as a cofactor in enzyme reaction but also prevents toxic effect induced by heavy metal such as copper and cadmium. To demonstrate the effect of heavy metals on pancreatic secretion, part of uncinate pancreas was taken and incubated in Krebs-Ringer bicarbonate buffer with heavy metals used. Additional treatment with CCK-OP was performed when needed. After incubation during different period of time, medium was analyzed for amylase activity using Bernfeld's method. The present study was attempted in order to elucidate the effect of several kinds of heavy metal on exocrine pancreatic secretion in vitro. The results obtained are as follows: 1) CCK-OP stimulated significantly amylase release from pancreatic fragments in vitro. 2) CCK-OP response of amylase release from pancreatic fragments was inhibited by treatmant with cadmium, especially high doses of cadmium. 3) CCK-OP response of amylase release from pancreatic fragments was inhibited when pretreated with $10^{-4}M$ copper chloride. 4) Lead chloride at the concentration of $10^{-3}M\;and\;10^{4}M$ stimulated the basal amylase release in vitro but CCK-OP response did not augment by lead chloride. 5) Zine chloride did not affect amylase release from pancreatic fragment in vitro. From the results mentioned above, it is suggested that CCK-OP response was inhibited it the amylase release from pancreatic fragments pretreated with cadmium and copper chloride.

• 대한화학회지
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• 제34권2호
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• pp.203-210
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• 1990

의약 전달체에 사용되는 생체분해성 고분자로서 L-lactic acid 와 L-glutamic acid가 각기 다른 조성비로 이루어진 공중합체를 합성하였다. Poly (L-lactide)는 zink oxide를 이용하여 합성하였으며, Poly (L-lactide) 말단에 3-Amino-l-propanol을 도입시킨 다음 이미 합성된 γ-benzyl-L-glutamate-N-carboxyanhydride (γ-BLG-NCA)를 개환중합시켜서 block copoly (L-lactide-γ-benzyl-L-glutamate)를 합성하였다. NMR로써 L-lactide와 γ-BLG-NCA가 서로 일정한 비율로 이루어진 공중합체가 합성되었음을 확인하였으며, 생성된 공중합체들의 열적성질은 시차주사열량계법 및 열무게 측정법으로 조사하였다.

• Toxicological Research
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• 제32권4호
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• pp.301-309
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• 2016

Due to undesirable hazardous interactions with biological systems, this investigation was undertaken to evaluate the effect of chronic exposure to silver on certain biochemical and some oxidative stress parameters with histopathological examination of brain, as well as the possible protective role of selenium and/or vitamin E as nutritional supplements. Thirty six male rats were divided into six groups of six each: the first group used as a control group. Group II given both vitamin E (400 mg/kg) of diet and selenium (Se) (1 mg/L) in their drinking water. Group III given silver as silver nitrate ($AgNO_3$) (20 mg/L). Group IV given vitamin E and $AgNO_3$. Group V given both $AgNO_3$ and selenium. Group VI given $AgNO_3$, vitamin E and Se. The animals were in the same exposure conditions for 3 months. According to the results which have been obtained; there was an increase in serum lactate dehydrogenase (LDH), lipase activities and cholesterol level, a decrease in serum total protein, calcium and alkaline phosphatase (ALP) activity in Ag-intoxicated rats. Moreover, the findings showed that $Ag^+$ ions affected antioxidant defense system by decreasing superoxide dismutase (SOD) activity and increasing vitamin E concentration with a high level of malondialdehyde (MDA) in brain tissue. The histological examination also exhibited some nervous tissue alterations including hemorrhage and cytoplasm vacuolization. However, the co-administration of selenium and/or vitamin E ameliorated the biochemical parameters and restored the histological alterations. In conclusion, this study indicated that silver could cause harmful effects in animal body and these effects can be more toxic in high concentrations or prolonged time exposure to this metal. However, selenium and vitamin E act as powerful antioxidants which may exercise adverse effect against the toxicity of this metal.

• 대한화학회지
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• 제23권3호
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• pp.175-179
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• 1979

Phthalimido기와 2,2,2-trichloroethyl기는 acetic acid와 같은 산성용매에서 zine dust에 의하여 각각 3-hydroxyphthalimidino기로 환원 되거나 혹은 환원분해된다. 그러나 THF-pH 4.5 buffer 혼합용매를 사용하므로써, free carboxylic acid가 존재하지 않는 경우, phthalimido는 환원시키지 않고 2,2,2-trichloroethyl기만을 선택적으로 환원분해시킬 수 있음을 발견하였다. 따라서 $2,2,2-trichloroethyl 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-{\beta}-D-glucopyranose$ (1)를 THF-pH 4.5 butter 혼합용매에서 zinc dust와 반응시키면, 2,2,2-trichloroethyl 기만이 선택적으로 환원분해된 $3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-{\beta}-D-glucopyranose$ (5)를 좋은 수득율로 얻을 수 있었다.

• 한국결정성장학회지
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• 제1권2호
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• pp.46-58
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• 1991

$Zn(NO_3)_2\cdot6H_2O$ 를 사용하여 출발용액으로 $Zn(NO_3)_2\cdot6H_2O$(aq.)용액을 각각 1M, 0.5M, 0.25M, 0.1M의 농도로 제조하여 초음파 진동자에 의해 액적을 발생시킨후, 2.3cm/sec의 유속으로 건조 및 열분해하여 ZnO분말을 합성하였다. 이때 건조 온도는 $200^{\circ}C$, 열분해 온도는 $600^{\circ}C$였다. 제조된 ZnO분말의 열적특성을 TG-DTA로 측정하였고, IR로 미분해물 및 흡착 가스의 성분을 조사하였다. 결정상 및 crystallite의 크기를 XRD로 분석하였고, 입자의 형태는 SEM과 TEM으로 관찰한 후 입자 크기와 입도분포를 SEM 사진으로부터 측정하였다. 합성 분말은 hexagonal의 결정구조를 갖는 Zinc oxide였다. 입자의 형태는 대부분 구형이고, 약 40nm 크기의 일차입자로 구성된 이차입자였다. 평규 입자 크기는 $0.28-0.61{\mu}m$ 이고 입도 분포도 좁았다.

• 한국수산과학회지
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• 제22권5호
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• pp.370-374
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• 1989

오징어 가공중의 향기성분의 변화를 알아보기 위하여 Nikerson형 연속추출장치(SDG)를 이용하여 시료의 향기성분을 추출한 후 중성, phenol성, 염기성 및 산성획분으로 나누어 중성 및 염기성획분을 GC 및 GC-MS로 분석$\cdot$동정한 결과 중성획분에서 31성분, 염기성 획분에서 7성분 분석$\cdot$동정되었다. 오징어 가열시료에서 3-methylthiophene, 2-methyl-2-hexanethiol 등의 함황화합물이 검출되었고 탄소수 5인 1-ponton-3-ol, 3-ponton-2-ol, 4-me-thyl-3-pentanal 및 탄소수 3인 3-methyl-1,2-propan-diol, 1-hydroxy-2-propanone과 hexanal, benzaldehy-de를 비롯한 탄소수가 8과 9인 alcohol, ketone 등이 검출되었다. 염기성획분에서는 trimethylamine을 비롯한 6종의 pyrazine류가 분리$\cdot$동정되었으며 2,5-dimethyl pyrazine, 2-ethyl-6-methyl pyrazine, 2,3,5-trimethyl pyrazine 등과 특히 2-ethyl-3,5-dimethyl pyrazine의 함량이 많아 염기성획분의 주된 향기성분으로 나타났다.

• 자원리싸이클링
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• 제13권1호
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• pp.22-27
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• 2004

전기로제강분진을 환원휘발시켜 얻은 조산화아연을 염화암모늄용액으로 침출, 전해채취하여 99.9％(3-Nine) 이상의 고순도금속아연을 회수하기 위하여 침출용액 중의 Pb 및 Cd 불순원소이온들의 석출, 제거에 관한 기초실험을 수행하였다. Pb 및 Cd 이온 등의 석출, 제거는 금속아연분말의 첨가에 의한 cementation 반응을 이용하였으며, 정제된 용액을 전해액으로 사용한 전해채취실험을 수행하여 정액 중의 Pb 및 Cd 이온농도가 회수되는 금속아연 중의 Pb 및 Cd 함량에 미치는 영향을 분석하여 3N 이상의 고순도금 속아연 회수를 위한 정액조건을 조사, 검토하였다. Pb 및 Cd 이온농도가 각각 2ppm 및 0.1 ppm 이하인 정액을 전해액으로 사용할 때 3N 이상의 고순도금속아연을 회수할 수 있었으며, 이때 침출용액의 정액에 필요한 금속아연분말 첨가량은 8.5g/l 이상으로 조사되었다. 또한 정액과정에서 금속아연분말 첨가 시 용액의 Eh 변화를 측정하여 Eh 변화에 의한 금속아연분말첨가량의 제어가능성을 검토하였다.

• 대한수의학회지
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• 제33권3호
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• pp.493-505
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• 1993

Present experiments were undertaken in order to clarify the clinico-pathological characteristics of lead poisoning in goats. Twenty goats were divided into three experimental groups(A, B and C) and a control(D). The three experimental groups received diets contaminated artificially with 10(A group), 200(B group) and $1,000(C group){\mu}g/g$ of lead for 70 days, respectively. The control group received normal diets. Hair samples collected one or two weeks interval were examed for the lead content. On day 70. all the animals were necropsied and various organs were examined pathoanatomically. In addition, various organs were analyzed for lead, zine, copper, iron and calcium content by atomic absorption spectrophotometry. From these experiments following results were obtained ; The lead content of hair was significantly increased from the $42^{nd}$, $21^{st}$ or $14^{th}$ day in all the three groups, which showed significant correlation with lead content of liver and spleen. The lead content of various organs including kidney, liver, spleen, ileum, bone and abomasum were significantly increased in accordance with the lead contamination. The increase was most prominent in abomasal wall. The zinc and copper content of liver, brain, ileum, skin, kidney, lung or muscle were increased in B and C groups whereas the iron and calcium content showed no significant change. Pathoanatomically, degeneration or necrosis of proximal convoluted tubules of kidney, peripheral necrosis of liver, fundic gland necrosis of abomasum and cerebral edema were observed in B and C groups.