• 대한치과보철학회지
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• 제42권6호
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• pp.628-640
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• 2004

Statement of problem. Wear as a result of repeated closing/opening cycles may decrease the friction coefficient of screw head, threads, and other mating components and, consequently, resistance to opening gradually decreases. It may cause screw loosening, which is one of the most common failures in implant prosthesis. Purpose. The purpose of this study is to evaluate the changes on the head and thread surface of the abutment screws after repeated closing and opening through the examination of tested screws in SEM(scanning electron microscope). Materials and methods. Five species of abutments were selected (3i-three, Avana-two) respectively by two pieces. The implant fixtures were perpendicularly mounted in liquid unsaturated polyesther(Epovia, Cray Valley Inc.) with dental surveyor. Each abutment was secured to the implant fixture by each abutment screw with recommended torque value using a digital torque controller. The abutment screws were repeatedly tightened and removed 20 times with a digital controller. FESEM (field emission scanning electron microscope, Netherland, Phillips co., model:XL 30 SFEG) was used to observe changes of each part caused by repeatedly closing/opening expeiment. First, the Photomicrographs of pre-test screws provided by each manufacturer were taken. The changes of each screw were investigated after every fifth closing and opening experiment with FESEM. Scaning electron microscope photomicrographs of each screw were taken four times. Results. As the number of closing and opening was increased, the wear or distortion of hexed or squared slot that contacted with the driver tip was more severely progressed. Wear or distortion of hexed slot was more severe than that of squared slot and it was more remarkable in the titanium screw than in the gold screw. All the tested screws showed that the width in the crest of their screw thread decreased gradually as the test was proceeded. Conclusions. Conclusively, we recommend the clinical use of gold screw, a periodic exchanges of abutment screws and avoiding repeated closing/opening unnecessarily. We also suggest a more careful manipulation of the abutment screw and screw-driver and using of abutment screw with an acute-angled slot design rather than an obtuse-angled one. Finally, it is suggested that the new slot design and the surface treatment for enduring wear or distortion should be devised.

• 대한바이러스학회지
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• 제29권4호
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• pp.271-281
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• 1999

The nested polymerase chain reaction (PCR) assay was used to determine the sequences of reverse transcriptase (RT) codons 41, 67, 70, 210, 215 and 219 of human immunodeficiency virus-1 (HIV-1) pol gene. Template DNA was obtained from uncultured peripheral blood mononuclear cells from 27 Korean HIV-1 infected patients treated with ZDV and Korean red ginseng. The second PCRs were done for 2 separated regions (RT codons $13{\sim}98$ and $152{\sim}259$) with $5\;{\mu}l$ of the first PCR productNucleotide sequences were determined by direct sequencing. In the 27 patients, CD4+ cell count decreased from $230{\pm}117/{\mu}l$ to $152{\pm}162/{\mu}l$ for $46{\pm}26$ months (Mo), and actual duration of ZDV intake was $72{\pm}16$ Mo. In the 16 patients who had been treated with ZDV therapy ${\ge}25$ Mo, the incidences of 70R, 215F/Y, and 41L were 61%, 28% and 22%, respectively and those of 67N, 210W and 219Q were 17%. The incidences of 215F/Y were 6.7% for group ${\le}12$ Mo treatment, 22.7% for group with 13 to 24 Mo, and 27.8% for group ${\ge}25$ Mo. There was no mutation in 9 patients. It might be associated with the interruption of ZDV therapy for more than 6 months in 6 patients. This study shows that the detection of mutation could be useful prognostic marker with other clinical and virological data, and very low mutation rate is dectected compared to overseas reports.

• Journal of Plant Biotechnology
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• 제34권4호
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• pp.347-354
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• 2007

유전자변형 작물의 상업화를 위해서는 유전자변형 작물이 식품으로서의 안전성과 환경에 미치는 영향에 관한 평가가 이루어져야한다. 이를 위해 개발자는 유전자변형 작물의 방출이전에 유전자변형 작물 개발에 관한 정보를 제출해야만 한다. 본 연구는 유전자변형 작물의 환경 위해성 평가를 위한 분자생물학적 자료를 제공하고자 수행하였다. 아그로 박테리움 형질전환법을 통하여 해충저항성 CryIAc 유전자가 도입된 배추 형질전환체를 획득한 후, 분자생물학적인 분석을 통하여 유전자의 copy수, 안정성, 식물체내에서의 발현을 확인하였고, T-DNA의 배추게놈내의 인접서열을 분석하였다. T-DNA의 게놈내 삽입 인접서열을 바탕으로 유전자변형 배추를 동정할 수 있는 프라이머를 제작하였고, 이를 이용한 검정방법을 수립하였다. 계통 특이 프라이머를 이용한 해충저항성 배추 후대의 PCR 분석결과와 제초체 처리결과가 서로 일치하였다. 본 연구 결과로 환경위해성 평가를 위한 해충저항성 배추의 분자생물학적인 자료를 획득하였으며, 개발된 프라이머는 해충저항성 배추의 검출을 위하여 유용하게 사용할 수 있음을 확인하였다.

• 한국잡초학회지
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• 제10권4호
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• pp.285-293
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• 1990

제초제(除草劑)에 내성(耐性) 또는 저항성(抵抗性)을 지닌 수도(水稻) 카루스를 선발(選拔)하기 위하여 유묘기(幼苗期)에 제초제(除草劑)에 반응(反應)을 달리하는 품종(品種)을 대상으로 카루스의 생장(生長) 반응(反應)을 조사(調査)한 결과(結果)는 다음과 같다. 카루스 유도시(誘導時)에 thiobencarb에 감수성(感受性)을 보였던 IR28의 카루스 생장(生長)은 thiobencarb $10^{-5}$ M 및 $10^{-6}$ M에서도 억제(抑制) 되지 않아 특정(特定) 제초제(除草劑)에 대한 수도(水稻) 품종(品種)의 반응(反應)은 카루스의 유도기(誘導期) 및 생장기(生長期), 성식물체(成植物體)에 따라 차이(差異)가 있음을 나타내었다. Butachlor에 대한 IR31917-45-3-2-2의 반응(反應)도 IR28과 유사(類似)한 결과(結果)를 보였다. Thiobencarb에 내성(耐性)을 지닌 카루스를 선발(選拔)키 위하여 IR28의 카루스를 thiobencarb $10^{-6}$ M에 30일간(日間) 처리(處理)한 후(後) 고농도(高濃度)인 $10^{-5}$ M에 옮겨 치상(置床)시킨 결과(結果) 카루스의 생체중(生體重)은 전혀 억제(抑制) 되지 않아서 제초제(除草劑) 내성세포(耐性細胞)를 선발(選拔)키 위해서는 제초제(除草劑)의 농도(濃度)를 점진적(漸進的)으로 높이는 것이 유용(有用)한 선발방법(選拔方法)이 될 것으로 사료(思料)된다.

• 생명과학회지
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• 제19권1호
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• pp.87-93
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• 2009

양식 어류의 항생제 투여의 문제점을 해결하기 위하여 한 약재 추출물을 기질로 한 유산균 배양액을 양식 넙치와 돌돔의 사료에 첨가하여 성장, 혈액학적 분석, 식세포 활성, lysozyme 활성 및 어류질병세균에 대한 공격실험을 실시하였다. 성장의 결과 넙치는 실험구와 대조구강의 유의성을 보이지 않았으며, 돌돔의 경우 대조구에 비해 실험구가 약 20 g 높은 어체중 증가를 보였다. 넙치의 사료효율은 실행구가 대조구에 비해 약 25% 높았으며, 돌돔은 사료효율은 두 그룹 간에 유의성을 보이지 않았다. 어류의 혈액학적 분석 결과, GOT와 GPT는 8주 이후에 감소현상을 보였으나 glucose와 total protein은 두 그룹 간에 유의성을 보이지 않았다. 식세포 활성 또한 유의적인 차이가 없었다. lysozyme 활성은 넙치의 경우 8주부터 실험구가 대조구보다 높은 활성을 보였으며, 돌돔은 실험 12주에 대조구보다 약 3배 높은 활성을 보였다. 어류 질병 유발세균에 대한 공격실험은 넙치의 복강에 V. anguillarum을 투여하였을 시, 실험구가 대조구에 비해 18%, S. iniae을 투여하였을 시, 실험구가 23% 높은 생존율을 보였다. 돌돔의 경우, V. anguillarum의 투여경과 대조구의 비해 17%, S. iniae의 투여경과 대조구의 비해 16% 높은 생존율을 나타냈다.

• Molecules and Cells
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• 제39권12호
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• pp.898-908
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• 2016

Despite recent groundbreaking advances in multiple myeloma (MM) treatment, most MM patients ultimately experience relapse, and the relapse biology is not entirely understood. To define altered gene expression in MM relapse, gene expression profiles were examined and compared among 16 MM patients grouped by 12 months progression-free survival (PFS) after autologous stem cell transplantation. To maximize the difference between prognostic groups, patients at each end of the PFS spectrum (the four with the shortest PFS and four with the longest PFS) were chosen for additional analyses. We discovered that integrin-${\alpha}8$ (ITGA8) is highly expressed in MM patients with early relapse. The integrin family is well known to be involved in MM progression; however, the role of integrin-${\alpha}8$ is largely unknown. We functionally overexpressed integrin-${\alpha}8$ in MM cell lines, and surprisingly, stemness features including $HIF1{\alpha}$, VEGF, OCT4, and Nanog, as well as epithelial mesenchymal transition (EMT)-related phenotypes, including N-cadherin, Slug, Snail and CXCR4, were induced. These, consequently, enhanced migration and invasion abilities, which are crucial to MM pathogenesis. Moreover, the gain of integrin-${\alpha}8$ expression mediated drug resistance against melphalan and bortezomib, which are the main therapeutic agents in MM. The cBioPortal genomic database revealed that ITGA8 have significant tendency to co-occur with PDGFRA and PDGFRB and their mRNA expression were up-regulated in ITGA8 overexpressed MM cells. In summary, integrin-${\alpha}8$, which was up-regulated in MM of early relapse, mediates EMT-like phenotype, enhancing migration and invasion; therefore, it could serve as a potential marker of MM relapse and be a new therapeutic target.

• 대한후두음성언어의학회지
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• 제20권1호
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• pp.63-67
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• 2009

Background and Objectives: In patients with asthma, increased obstruction and resistance of airway result in impairment in the generation of voice. Allergy and nasal polyposis, which are frequently observed in patients with asthma, are other factors that affect the vocal performance. Bronchodilators and steroids are commonly used in the treatment of asthma, and these agents also have been reported to be associated with voice changes. The aim of this study is to evaluate the voice quality in patients with mild to-moderate asthma by subjective and objective methods. Materials and Methods: A total of 36 patients with asthma established in the Department of Respiratory Medicine were included in this study. 23 were women and 13 were men, with a mean age of 51.7 years. The average duration of asthma was 77.0 months. All patients had mild-to moderate asthma. Acoustic and aerodynamic analyses were performed and the movements of the vocal cords were examined by videolaryngostroboscopy (VLS). Voice Handicap Index (VHI) and GRABS scales were used for subjective evaluations. Results: 50% of patients suffered from dysphonia and FO was 119.3${\pm}$23.7 Hz in male and 198.2${\pm}$18.4 Hz in female patients. There were no significant differences in average shimmer and NHR between females (4.90${\pm}$2.95% ; 0.1O${\pm}$0.04 dB) and males (4.64${\pm}$2.45% ; 0.20${\pm}$0.15 dB). However, the value of jitter was greater for females (2.60${\pm}$1.92%) than for males (1.21${\pm}$0.84%). The VHI score was above the normal limit in 35%, and VLS findings were shown diverse abnormality in 89% asthmatics from mucosal change to hyperfunction of supragottis and contact granuloma. But duration of illness and steroid dose did not correlate with these findings. Conclusion: Subjective and objective abnormality was shown in more than 50% of asthmatic patients. We suggest that persons who suffer from asthma should be examined for possible voice disorders by laryngologist. Additionally, appropriate medical care and voice therapy should be provided for those who have voice disorders associated with asthma.

• 한국동물위생학회지
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• 제24권1호
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• pp.31-41
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• 2001

This study was carried out to identify causative agents from california mastitis test(CMT) positive mastitic milk, and to examine the antimicrobial susceptibility of 50 heads in Seongju and Chilgok area of Gyeongbuk province. Sulfadimethoxine sodium(SMS) was intramuscularly administered once to four mastitis Infected dairy cattle at the rate of 10mg/kg body weight. After injection of SMS, the depletion rate of serum and milk from the cattle were periodically measured for five days. The CMT positive number from 50 heads showed 46% and that of 200 quarters was 47(23.5%). From 39 quarters of 47 heads 39 different microorganisms were identified. These organisms were classified into 12 species : Staphylococcus aureus 8(20.5%), Sta hemolyticus 6(15.4%), Streptococcus bovis 4(10.3%), Sta hyicus 3(7.7%), Sta epidemidis. Sta xylosus, Sta sciuri 2(5.1%), Str agalactiae 2(5.1%), Escherichia coli(10.3%), three Enterobacter cloacae(7.7%), two Ent aerogenes(5.1%) and one Salmonella spp(2.6%). As the results of antibiotic susceptibility test, gentamicin(Gm, 11 species 27 strains, 69.5%), cephalotin(Cf, 9 species 24 strains, 61.5%), sulfamethoxazole(Stx, 8 species 14 strains, 43.6%), tetracycline(Tc, 8 species 14 strains, 35.9%), and streptomycin(Sm), lincomycin(Lm), cefoperazon(Cp) and penicillin(Pc) have a highly resistance(7.7% ～5.1%). However, carbenicillin (Cb), amikacin(Ah) have no susceptible for all drugs. The mean residual concentration of SMS in serum according to the time lapsed were showed 33.964 $\pm$ 4.435ppm at the 4 hours after intramuscularly injection(AII). It was significantly(p<.05) decreased to 6.596 $\pm$ 3.402, 0.217 $\pm$ 0.119 and 0.005 $\pm$ 0.004ppm at the 1st, 3rd and 5th day AII. The mean concentration of SMS in milk was significantly(p<.05) decreased from 0.920 $\pm$ 0.42ppm to 0.084 $\pm$ 0.016ppm between 8 hours and 1 day AII. As the results of this experiments, sulfadimethoxine was residued at the level of no less than 0.01ppm in milk on the 2nd day AII. Thus, this results would be able to be used the basic index for prevention of sulfonamides residue in milk after treatment of dairy mastitis.

• 한국잡초학회지
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• 제18권3호
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• pp.237-245
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• 1998

Bacillus subtilis protoporphyrinogen oxidase 유전자를 Agrobacterium을 매개체로 이용하여 전이 시킨 후 cauliflower mosaic virus 35S promoter하에서 발현케 한 형질전환 담배를 유기하였다. 이러한 형질전환 담배의 diphenyl ether계 제초제 oxfluorfen에 대한 생리적 반응과 여러 환경 조건에서의 생장 반응을 재배종 담배와 비교하였다. Oxyfluorfen의 처리에 의해 나타나는 세포내 구성물질의 누출과 지질과산화작용은 재배종 담배에서보다 형질전환 담배에서 더 작게 이루어졌다. 형질전환 담배의 생장을 여러 온도, 광도 및 수분 조건에서 조사한 결과, 저광도와 포화수분 조건에서의 생장이 재배종 담배에 비해 다소 저하되는 현상이 나타났을 뿐 기타 조건에서의 생장은 재배종 담배의 생장과 거의 동일하였다. 따라서 B. subtilis protoporphyrinogen oxidase 유전자를 전이시켜 cauliflower mosaic virus 35S promoter하에서 발현케 한 형질전환 담배는 oxyfluorfen에 대해 비교적 높은 저항성을 나타내지만 형질전환에 따른 생장 변화는 크게 일어나지 않음을 알 수 있었다. 한편 이러한 형질전환 담배의 oxyfluorfen에 대한 저항성 기작에 대해서도 논의하였다.

• Journal of the Korean Wood Science and Technology
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• 제28권4호
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• pp.41-50
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• 2000

Cement-bonded particleboard is being used as outdoor siding material all over the world, because this composite particularly bears a light weight, high resistance against fire, decay, and crack by cyclic freezing and thawing, anti-shock property, and strength enhancement. Construction systems are currently changing into a frame-building style and wooden houses are being constructed with prefabrication type. Therefore, they require a more durability at outdoor-exposed sides. In this study, the cement hydration property for Korean pine particle, Japanese larch particle and face- and middle layer particles (designated as PB particle below) used in Korean particleboard-manufacturing company was investigated, and the rapid manufacturing characteristics of cement-bonded particleboard by supercritical $CO_2$ curing was evaluated. Korean pine flour showed a good hydration property, however, larch flour showed a bad one. PB particle had a better hydration property than larch flour. The addition of $Na_2SiO_3$ indicated a negative effect on hydration, however, $MgCl_2$ had a positive one. Curing by supercritical $CO_2$ fluid gave a conspicuous enhancement in the performances of cement-bonded particleboards compared to conventional curing. $MgCl_2$ 3%-added PB particle had the highest properties, and $MgCl_2$ 1%-added Korean pine particle had the second class with the conditions of cement/wood ratio of 2.7, a small fraction-screened particle and supercritical curing. On the contrary, the composition of non-hammermilled or large fraction-screened particle at cement/wood ratio of 2.2 was poorer. Also, the feasibility for actual use of 3%-added, small PB particle-screened fraction was greatest of all the conventional curing treatments. Relative superiority of supercritical curing vs. conventional curing at dimensional stability was not so apparent as in strength properties. Through the thermogravimetric analysis, it was ascertained that the peak of a component $CaCO_3$ was highest, and the two weak peaks of calcium silicate hydrate and ettringite and $Ca(OH)_2$ were present in supercritical treatment. Accordingly, it was inferred that the increased formation of carbonates in board contributes to strength enhancement.