• 한국방사선학회논문지
• /
• 제11권4호
• /
• pp.189-195
• /
• 2017

방사선 특히, 엑스선 또는 감마선으로부터 인체를 보호하기 위해 납(Pb)으로 된 보호 장구를 광범위하게 사용해왔다. 최근 납 중독 및 환경오염의 문제로 납을 대신하는 무연 방사선 차폐재의 개발이 활발히 이루어지고 있다. 차폐재의 성능 확보를 위해서는 제작 및 평가의 순환 사이클을 반복하게 된다. 본 연구는 실제 무연 방사선 차폐소재의 제작에 앞서 차폐재의 성능을 몬테카를로 전산모사를 통해 확인함으로써 가능한 차폐소재의 조합을 연구하였다. 방사선 차폐소재의 평가에 사용되는 조건으로 엑스선관을 Geant4를 이용하여 전산모사하고 획득된 광자 스펙트럼을 이용하여 텅스텐과 비스무스의 조합에 따른 차폐소재의 성능을 평가하였다. 차폐소재의 공극에 따른 성능 저하도 평가하였다. 방사선 차폐 소재 개발 시 공극률을 줄이는 것이 중요한 인자라는 것을 알 수 있었다.

• Journal of Preventive Medicine and Public Health
• /
• 제7권2호
• /
• pp.377-381
• /
• 1974

Determination of lead in urine is important in industrial hygiene and toxicology. Dithizone method has been principally used for the determination of lead in urine, which gives accurate results in skilful hands but is usually complex and time-consuming. Atomic absorption spectrophotometry is a new simple method and several procedures have been described. However, the influences of pH and the presence of chelating agents during treatment of lead poisoning are not clear. The purpose of this study was to find out the effect of pH and chelating agents on the determination of lead using Shimadzu atomic absorption/flame spectrophotometer, model AA-610. The results obtained were as follows: 1. The atomic absorption spectrophotometry(AAS) could be applied without prior acid digestion to specimens in the absence of chelating agents. The absorbance at $2,170\;{\AA}$, though more sensitive, was more noisy electronically. Therefore, we selected the wavelength of $2,833\;{\AA}$ plus scale expansion. 2. The optimal pH was in the range from 2 to 3. 3. The sensitivity was $0.075{\mu}g/ml/%$ and detection limit was about $0.2{\mu}g/ml$. 4. In the presence of EDTA, lead could not be completely determined without prior acid digestion. 5. On specimens from patients receiving penicillamine therapy, a comparison was made between the values obtained with dithizone method and AAS method with prior acid digestion. The results of comparison showed a very good agreement.

• Archives of Pharmacal Research
• /
• 제24권1호
• /
• pp.55-63
• /
• 2001

Aucubin, an irdoid g1ucoside, was investigated to determine whether it has a stimulating effect on $\alpha$-amanitin excretion in $\alpha$-amanitin intoxicated rats, and whether there is binding activity to calf thymus DNA. High-performance liquid chromatography (HPLC) analysis of $\alpha$-amanitin in rat urine allowed quantitative measurement of the $\alpha$-amanitin concentration with a detection limit of 50${mu}g/ml$. In this system, a group treated with both $\alpha$-amanitin and aucubin showed that o(-amanitin was excreted about 1.4 times faster than in the $\alpha$-amanitin only treated group. Our previous results showed that the toxicity of $\alpha$-amanitin is due to specific inhibition of RNA polymerase activity and the resultant blockage of the synthesis of certain RNA species in the nucleus. However, no significant activity change on RNA polymerase from Hep G2 cells was observed when aucubin was treated with $\alpha$-amanitin at any concentration tested. Nevertheless, aucubigenin inhibited both DNA polymerase (IC50, 80.5${mu}g/ml$) and RNA polymerase (IC50, 135.0${mu}g/ml$) from the Hep G2 cells. The potential of both $\alpha$-amanitin and aucubin to interact with DNA were examined by spectrophotometric analysis. $\alpha$-Amanitin showed no significant binding capacity to calf thymus DNA, but aucubin was found to interact with DNA, and the apparent binding constant ($K_{app}$) and apparent number of binding sites per D7A phosphate ($B_{app}$) were 0.45$0.45{\times}$$10^4$ $M^{-1}$ and 1.25, respectively.

• 한국환경보건학회지
• /
• 제12권2호
• /
• pp.1-9
• /
• 1986

The purpose of this study is to determine the antidotal effects of thiamine in phenylmercury poisoning rats. Sixty-six rats were divided into six groups the control group, the $40{\gamma}$ thiamine-only-dosed group, the 6 ppm phenylmercury-only-dosed group, the simultaneously-dosed-group with 6 ppm mercury & $20{\gamma}$ thiamine, and with 6 ppm mercury & $40{\gamma}$ thiamine, and with 6 ppm mercury & $80{\gamma}$ thiamine. The thiamine was put into pellet by various concentrations, and phenylmercury was mixed in drinking water by 6 ppm concentration. The rats were sacrificed for observing the histopathological changes of brain, liver and kidney. The remits summarized are as follows 1. In the group dosed with only $40{\gamma}$ thiamine, the tissues of brain, liver and kidney did not show any abnormal architecture. 2. The phenyhnercury-only-dosed group and the simultaneoulsy-dosed group with mercury and $20{\gamma}$ thiamine showed remarkable degenerative or necrotic hepatic cells. In addition, a remarkable swelling and necrosis on epithelium of proximal tubules in kidney were found. 3. The simultaneously-dosed group with mercury and $40{\gamma}$ thiamine showed moderate degeneration and necrosis of Purkinje cells in cerebellum. A moderate necrosis and swelling on epithelium of proximal tubules and a large amount of tubular casts were found as well. 4. The simultaneously-dosed group with mercury and $80{\gamma}$ thiamine showed a slight degenerative change of Purkinje cells. A slight degenerative change on epithelium of proximal tubules and a small amount of tubular casts were also found.

• 한국주조공학회지
• /
• 제30권4호
• /
• pp.147-150
• /
• 2010

알루미늄 합금의 미세조직 개량을 위한 목적으로 사용되는 Al-Ti-B 합금계의 미세화제는 재활용 과정에서 붕소(B)의 농축(Agglomeration) 문제 및 Zr, Si, Cr 등을 함유하는 합금에서 미세화 효과가 급격히 감소하는 Poisoning effect 등이 지적되어 왔다. 최근에는 이를 대체할 수 있는 Al-Ti-C 합금계의 미세화제에 대한 연구가 활발한데 이는 TiC가 용탕 내에서 ${\alpha}$-Al의 핵생성처로 직접 작용하는 점에 착안한 것이다. 한편, 이들 Al-Ti-B, Al-Ti-C 계의 미세화제는 그 제조공정에서 $K_2TiF_6$를 이용함에 따라 불소함유 유해가스를 배출하여 환경 문제를 야기하고, 이를 포집/정화하기 위한 추가설비를 요구하게 된다. 따라서 대기 환경 오염 및 경제성 측면에서 유리한 미세화제의 친환경 제조기술에 대한 개발이 필요한 시점이다. 본 연구에서는 $K_2TiF_6$를 사용하지 않고 용탕 내의 자발적 반응을 이용하여 환경 및 경제적 측면에서 유리한 Al-Ti-C 미세화제를 개발하고자 하였다. A3003 합금을 대상소재로 하여 개발된 Al-Ti-C 미세화제와 상용 Al-Ti-B 미세화제의 미세화 도달시간 및 fading 발생 등을 비교하였다. 본 연구를 통하여 개발된 Al-8.6Ti-0.025C 미세화제는 상용 Al-Ti-B 미세화제 보다 적은 첨가량에도 유사한 미세화 성능을 나타내었으며 용탕 유지시간 100분까지도 fading이 발생하지 않는 것을 확인하였다.

• Preventive Nutrition and Food Science
• /
• 제7권2호
• /
• pp.168-173
• /
• 2002

Gastrointestinal infections kill over two million people each year, and pathogen contamination of livestock causes many cases of food poisoning. Two candidate intestinal probiotic strains, L. rhamnosus GR-1 and L. fermentum RC-14 were found to inhibit the growth of Salmonella typhi, Shigella dysenteriae, E. coli O157:H7, Listeria monocytogenes, L. innocua, Enterococcus faecalis, and Bacteroides fragilis. In a series of mouse experiments, L. rhamosus GR-1 and L rhamnosus GG protected against S. typhimurium infection and translocation to the liver and spleen, reduced mortality and induced intestinal phagocytic and immunoglobulin responses. In a second series of experiments, the combination of L. rhamnosus GR-1 and L. fermentum RC-14 was superior to L. rhamnosus GG and placebo in protecting the mice from the lethal effect of salmonella. In summary, the use of combinations of probiotic lactobacilli as dietary supplements or foods could be considered for people at high risk of salmonella intestinal infection. Given the post-infection complications that can arise, such natural methods warrant further exploration especially given the increasing problem of antibiotic resistance and the lack of alternative measures available to many developing countries.

• 대한수의학회지
• /
• 제60권3호
• /
• pp.105-108
• /
• 2020

These days abattoirs' hygiene of Korea is regulated by Hazzard Analysis Critical Control Point (HACCP). Although 20 years have been left since first HACCP was adjusted in Korea, 12% of abattoirs got inconsistence on evaluations. Food poisoning caused by bacteria feces like pathogenic Escherichia coli and Salmonella has not decreased. These bacteria on meat cross-contaminate at the abattoir. Therefore, field verification of abattoir's critical control point (CCP) and experiments to find alternative ways of the CCP were conducted. The aerobic bacteria were measured before and after high-pressure water based washing process set as CCP in most abattoirs. Four parts of cattle carcasses were selected to apply sponge-swab method. The effects were < 1 log reduction which is not significant. Lactic acid (LC), chlorine dioxide (ClO₂) and slightly acidic electrolyzed water (SAEW) were used to measure the effect of reducing bacteria on beef by the different time. LC has 1.24-2.02 log reduction for aerobic bacteria. ClO₂ has 1.44-1.96 log reduction for aerobic bacteria. SAEW has 1.1-1.91 log reduction for aerobic bacteria. There was significant difference according to concentrations (p < 0.05). This study presents legitimacy for hygiene improvement of CCP by field verification. In addition, chemical disinfectants that can be mechanically applied have better reduction effects of high-pressure washing.

• Applied Microscopy
• /
• 제36권4호
• /
• pp.235-250
• /
• 2006

본 연구는 급성 납 독성에 대한 활성탄의 방어효과를 알아보기 위하여 시도되었다. 30g내외의 생쥐를 대상으로 대조군, 납(60mg/kg) 투여군, 납 투여 후 활성탄(40mg/kg) 투여군으로 구분하여 구강투여 한 후 간장, 신장손상 억제 효과를 알아보기 위하여 생화학적 및 조직학적 실험을 실시하였다. 혈액중 aspartate amiotransferase(AST). alanine amino-transferase(ALT)그리고 glucose(Glu)의 수치는 활성탄 투여군이 납 투여군보다 감소되었다. 전자현미경적 관찰 결과, 간장에서 납 투여군은 간세포의 핵이 함입되어 불규칙했으며 미토콘드리아와 조면소포체의 수조가 팽대되고, 리보솜의 탈락이 관찰되었다. 활성탄 투여군은 핵이 대조군과 같은 형태가 관찰되었고, 전자밀도가 높은 미토콘드리아가 분포되어 있었으며, 리보솜이 부착된 상태로 층판구조를 형성하는 조면소포체가 관찰되었다. 이상과 같은 결과, 활성탄이 납 중독된 생쥐에서 납을 흡착시킴으로서 손상된 간장에 보호 효과가 있는 것으로 사료된다.

• 한국식품저장유통학회지
• /
• 제11권2호
• /
• pp.207-213
• /
• 2004

다양한 기능성을 갖는 생약재 32종을 대상으로 천연보존료 개발의 일환으로 메탄올로 추출한 항균활성 물질을 몇 종의 병원균과 식중독균, 식품과 관련이 있는 세균, 젖산균 및 효모 등 12종의 균주 B. subtilis, M. luteus, Sta aureus, Sta. epidermidis, Strep. mutans, E. coli, Pse. aeruginosa, Sal. typhimurium, V. vulnificus, Lac. brevis, Leu. mesenteroides, Sacch. cerevisiae에 대하여 항균활성을 검색하였으며, 항균력이 강한 생약재 추출물은 최소저해농도(MIC)를 측정하였다. 검색한 결과 계피, 목단, 적양, 정향, 팔각향 등의 메탄올 추출물은 12균주 중 세균에 대하여 항균활성이 강하였으나, 젖산균 및 효모에 대해서는 낮은 항균활성을 보였다. 최소저해농도는 B. subtilis에 대해 강한 증식억제효과를 보였고, Sta. epidermidis나 Pse. aeruginosa에 대해서도 거의 모든 추출물이 저해활성을 나타내었다. 하지만 항균활성 측정시 거의 저해가 없었던 Lue. mesenteroides도 대부분의 추출물에서 억제 효과를 나타내 항균성과는 약간 다른 결과를 보였다. 생약재 중 강한 항균력을 보인 녹차, 정향, 적양, 인진호 등은 폴리페놀 함량이 약 7 mg/g 이상으로 높아 이들 페놀성 물질들이 항균활성에 많은 영향을 준 것으로 사료된다. 따라서 여러 미생물에 의해 변패될 수 있는 식품에서 천연보존료로의 이용이 가능할 것으로 생각된다.

• The Korean Journal of Physiology
• /
• 제10권1호
• /
• pp.41-48
• /
• 1976

Tetrodotoxin (TTX) is the purified active principle responsible for tetrodon (Puffer-fish) poisoning which has long been known in the Orient. The pharmacological actions of TTX have been rather extensively investigated. Two of the most prominent effects of intravenousely administered TTX are severe hypotension and respiratory paralysis resulting from its depressant actions on tissues. This depressant actions of TTX in turn result from the selective inhibition of sodium-carrying mechanism which is essential to generation of the action potential. TTX differs from local anesthetics in that it does not affect potassium conductance. Although the mechanism of the hypotensive action of TTX remains a subject of controversy, most investigator agree that TTX-induced hypotension is caused by alteration in the blood vessels rather than the heart. Not only the study on the effects of TTX on cardiac function is meager but the results of reported works are often contradictory. The present study was undertaken to investigate the effect of TTX on the electrocardiogram of the rabbit and to compare them with well known electrocardiographical characteristics found in digitalis and quinidine intoxicated animals. The results obtained from the present study are summarized as follows. 1. No changes were found in P-R interval and QRS duration after i.v. administration of $1.0\;{\mu}g/kg\;to\;1.5\;{\mu}g/kg$ TTX to the animals. It is obvious that there were no conduction disturbance between atria and ventricles as well as in the ventricular tissue. 2. In $1.0\;{\mu}g/kg$ TTX group, S-T interval and T-P segment were not changed whereas marked changes were observed in $1.5\;{\mu}g/kg$ TTX group. 3. The first and second degree A-V blocks appeared in the $2.0\;{\mu}g/kg$ TTX group. 4. TTX differs from digitalis and quinidine in that it does not cause S-T interval depression and T-wave inversion. In contrast with digitalis, TTX caused Q-T interval prolongation.