• Bulletin of the Korean Chemical Society
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• 제34권7호
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• pp.2001-2005
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• 2013

The second-order rate constants ($k_{OH^-}$) for the reactions of Y-substituted-phenyl diphenylphosphinates (4a-4i) with $OH^-$ in $H_2O$ at $25.0{\pm}0.1^{\circ}C$ have been measured spectrophotometrically. Comparison of $k_{OH^-}$ with $k_{EtO^-}$ (the second-order rate constants for the corresponding reactions with $EtO^-$ in ethanol) has revealed that $EtO^-$ is less reactive than $OH^-$ although the former is ca. 3.4 $pK_a$ units more basic than the latter, indicating that the reactivity of these nucleophiles is not governed by their basicity alone. The Br${\o}$nsted-type plot for the reactions of 4a-4i with $OH^-$ is linear with ${\beta}_{lg}$ = -0.36. The Hammett plot correlated with ${\sigma}^-$ constants results in a slightly better correlation than that correlated with ${\sigma}^{\circ}$ constants but exhibits many scattered points. In contrast, the Yukawa-Tsuno plot for the same reactions exhibits an excellent linear correlation with ${\rho}$ = 0.95 and r = 0.55. The r value of 0.55 implies that a negative charge develops partially on the O atom of the leaving group. Thus, the reactions of 4a-4i with $OH^-$ have been concluded to proceed through a concerted mechanism.

• ALGAE
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• 제33권4호
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• pp.291-304
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• 2018

Lyngbya C. Agardh ex Gomont is a nonheterocytous cyanobacterial genus whose evolutionary history is still poorly known. The traditionally defined Lyngbya has been demonstrated to be polyphyletic, including at least five distinct clades, some of which have been proposed as new genera. Intraspecific diversity is also clearly underestimated in Lyngbya due to the lack of unique morphological characters to differentiate species. In this study, we describe the new genus Capillus T. A. Caires, C. L. Sant'Anna et J. M. C. Nunes from benthic marine environments, including two new Brazilian species (here described as C. salinus T. A. Caires, C. L. Sant'Anna et J. M. C. Nunes, and C. tropicalis T. A. Caires, C. L. Sant'Anna et J. M. C. Nunes), and two species yet to be described, one of them from India (Capillus sp. 2.1), and the other from United States of America, based on strain PCC 7419. Capillus species presented cross-wise diagonal fragmentation, assisted or not by necridic cells, which has not been previously mentioned for Lyngbya. Ultrastructural analyses showed that C. salinus and C. tropicalis have numerous gas vesicles, which are rarely described for benthic marine species. The new genus formed a well-supported clade, and the D1-D1' and Box B secondary structures of internal transcribed spacer also supported the proposal of its new species. These findings help to clarify the diversity of species in the Lyngbya complex and the taxonomy of the group, and highlight the need of further floristic surveys in tropical coastal environments, which remain poorly studied.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권5호
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• pp.571-577
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• 2008

Introduction: Possible etiologic factors associated with bone loss around implants after implantation are surgical trauma, occlusal overload, periimplantitis, presence of micro gap and the formation of biologic distances. Tarnow et al. observed that the crestal bone loss was greater when the distance between the implants was <3mm than when the implants were ${\geq}\;3mm$ apart. The aim of this study was to evaluate the influence of different interimplant distance on marginal bone and crestal bone resorption in the beagle dogs. Materials and methods: The mandibular premolars of 5 dogs were extracted bilaterally. After 12 weeks of healing, each dog received 7 implants. On each side, implants were separated by 2mm (Group 1) and by 5mm (Group 2). After 16 weeks of healing, the dogs were sacrificed. Marginal bone loss was determined through linear measurements made between the implant-abutment junctions and the most coronal portions of the bone in contact with the implant surface. A line was drawn uniting the implant-abutment junctions of the adjacent implants, and a linear measurement was made at the midpoint in the direction of the most coronal peak of the interimplant bone crest to determine the crestal bone loss. Both of them was measured radiologically and histologically. Result and conclusion: In radiological analysis, the mean of marginal bone loss was $1.26{\pm}0.14mm$ for group 1 and $1.23{\pm}0.34mm$ for group 2, the mean of crestal bone loss was $1.10{\pm}0.14mm$ for group 1 and $1.02{\pm}0.30mm$ for group 2. The results were not statistically significant between 2 groups. In histological analysis, the mean of marginal bone loss was $1.63{\pm}0.48mm$ for group 1 and $1.62{\pm}0.50mm$ for group 2, the mean of crestal bone loss was $1.23{\pm}0.35mm$ for group 1 and $1.15{\pm}0.39mm$ for group 2. The differences were also not statistically significant. The clinical significance of this result is that the increase in the crestal bone loss results in the increase in the distance between the base of the interproximal contact of the crowns and the bone crest, and this determines if papilla will be present or absent between implants. Considering this fact, keeping up sufficient interimplant distance is important to minimize crestal bone loss.

• Bulletin of the Korean Chemical Society
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• 제26권9호
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• pp.1410-1414
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• 2005

Neopentyl arenesulfonates reacted with primary alkylmagnesium halides in the presence of $(PPh_3)_2NiCl_2$ to produce the corresponding alkylarenes. The efficiency of this coupling reaction considerably depends on the nature of catalyst and solvent. Highest yield was obtained by using three equivalents of Grignard reagent to a mixture of $(PPh_3)_2NiCl_2$ and arenesulfonate in refluxing $Et_2O$. This reaction represents a novel method allowing the efficient and creative substitution of sulfur-containing groups in aromatic compounds. It also shows that the alkyloxysulfonyl group might be a suitable alternative to halides and triflate in some circumstances.

• Journal of Microbiology
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• 제34권1호
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• pp.38-39
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• 1996

The internal regions of nuclear small subunit rRNA from 6 plaeurotus species and 5 Pleurotus ostreatus strains were amplified by PCR and sequenced. The DNA sequences of 8 Pleurotus strains (P. ostreatus NFFA2, NFFA4501, NFFA4001, KFFA4001, KFCC11635, P florida, P. florida, P. sajor-cuju, P. pulmonarius, and P. spodoleucus) were idential, but P. cornucopiae differed from them in two bases out of 605 bases. However, p[hylogenetic analysis of the sequences by DNA-distance matrix and UPGMA methods showed that P. ostreatus NFFA2m1 and NFFA2m2, known as mutants of P. ostreatus NFFA2, belonged to anther group of Basidiomycotina, which is close to the genus Auricularia. The difference of the SSU rDNA sequences of P. cornucopiae from other Pleurotus species tested corresponds to the difference of mitochondrial plasmid type present in Pleurotus species as observed by Kim et al. (1993, Korean J. Microbiol. 31, 141-147).

• Clinical and Experimental Reproductive Medicine
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• 제42권4호
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• pp.149-155
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• 2015

Objective: The goal of this study was to investigate the relationship between serum progesterone (P4) levels on the day of human chorionic gonadotropin (hCG) administration and the pregnancy rate among women undergoing controlled ovarian stimulation for in vitro fertilization (IVF) or intracytoplasmic sperm injection-embryo transfer (ICSI-ET) using a flexible antagonist protocol. Methods: This prospective study included 200 IVF and ICSI-ET cycles in which a flexible antagonist protocol was used. The patients were divided into five distinct groups according to their serum P4 levels at the time of hCG administration (0.80, 0.85, 0.90, 0.95, and 1.00 ng/mL). The clinical pregnancy rate (CPR) was calculated for each P4 interval. Statistically significant differences were observed at a serum P4 level of 0.9 ng/mL. These data suggest that a serum P4 concentration of 0.9 ng/mL may represent the optimal threshold level for defining premature luteinization (PL) based on the presence of a significant negative impact on the CPR. Results: The CPR for each round of ET was significantly lower in the PL group defined using this threshold (25.8% vs. 41.8%; p=0.019), and the number of oocytes retrieved was significantly higher than in the non-PL group ($17.3{\pm}7.2$ vs. $11.0{\pm}7.2$; p=0.001). Elevated serum P4 levels on the day of hCG administration were associated with a reduced CPR, despite the retrieval of many oocytes. Conclusion: Measuring serum P4 values at the time of hCG administration is necessary in order to determine the optimal strategy for embryo transfer.

• 한국수정란이식학회지
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• 제22권4호
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• pp.219-222
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• 2007

These study was carried out to investigate the effects of the collection time, culture time and activation of canine oocytes on in vitro maturation rates. The activated oocytes were cultured in 10% FCS+TCM-199 media containing hormonal supplements (10 IU/ml HCG, 10 IU/ml PMSG, 10 ug/ml gonadotropin) at 5% $CO_2$, 95% air, $38^{\circ}C$. 1. IVM rate of in vitro cultured cumulus-attached oocytes recovered from ovaries that collected at follicular and luteal stages of the reproductive cycles were 11.4% and 5.7%, respectively. IVM rate of oocytes recovered from ovaries that collected at follicular stages of the reproductive cycles was significantly higher than that of luteal stage (p<0.05). 2. When IVM was carried out at different periods of 40, 48, and 70 hrs, the IVM rates of oocytes matured in vitro were 2.9%, 8.6%, 5.7%, respectively. These results indicate that the IVM time between $48{\sim}70$ hrs gives the highest maturation rate for the oocytes matured at the different stages. 3. IVM rate of oocytes matured in vitro for 10 hrs after single and combined activation treatment by ET, IP and CH and Ca+DMAP, CH+DMAP, ET+CH were $11.5{\pm}1.2%,\;10.8{\pm}1.0%,\;9.6{\pm}1.2%\;and\;12.4{\pm}1.5%,\;11.8{\pm}1.5%,\;11.2{\pm}1.4%$ respectively. This was higher than that in both single and combined stimulated groups compared to control group ($6.2{\sim}7.2%$).

• Clinical and Experimental Reproductive Medicine
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• 제24권3호
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• pp.281-292
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• 1997

The objective of this study was to compare retrospectively the survival and pregnancy rates(PR) of cryopresered-thawed embryos obtained from intracytoplasmic sperm injection (ICSI) or conventional in vitro fertilization (IVF). Ninety-six cycles of cryopresered-thawed embryo transfer (ET) were performed in 79 patients from June, 1996 to September, 1997 and grouped as followings: 20 cycles (16 patients) inseminated by ICSI (ICSI Group) and 76 cycles (63 patients) by conventional IVF (IVF Group). Slow-freezing and rapid-thawing protocol was used with 1.5M propanediol (PROH) and 0.1M sucrose as cryoprotectant. All embryos were frozen-thawed at the two pronuclear (2 PN) stage excluding four cycles in which the early cleavage stage embryos were frozen, and allowed to cleave in vitro for one day before ET. The duration from freezing to thawing was comparable in both groups ($mean{\pm}SD$, $112.1{\pm}80.0$ vs. $124.8{\pm}140.1$ days). The age of female ($31.2{\pm}3.4$ vs. $32.6{\pm}3.3$ years) and the endometrial thickness prior to progesterone injection ($9.4{\pm}2.0$ vs. $9.3{\pm}1.8$ mm) were also comparable in both groups. There was no significant difference in the outcomes of cryopreserved-thawed ET between two groups: survival rate ($85.2{\pm}16.1%$ vs. $82.2{\pm}19.7%$), cleavage rate ($96.9{\pm}6.7%$ vs. $94.7{\pm}13.0%$), cumulative embryo score (CES, $54.5{\pm}31.1$ vs. $49.0{\pm}20.0$), preclinical loss rate (5.0% vs. 5.3%), clinical miscarriage rate (0% vs 29.4%), clinical PR per transfer (35.0% vs. 22.4%), implantation rate (9.9% vs. 5.6%), and multifetal PR (42.9% vs. 17.6%). In conclusion, human embryos resulting from ICSI can be cryopreserved-thawed and transferred successfully, and the survival rate and PR are comparable to conventional IVF.

• 한국균학회지
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• 제28권1호
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• pp.32-37
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• 2000

본 연구는 국내 주요 송이 산지에서 생산되는 송이{Tricholoma matsutake(S. Ito et Imai) Sing}의 개체간, 그리고 지역간 유전적 다양성을 구명하기 위하여 실시하였다. 경상북도의 봉화, 울진, 고령, 청도의 4개 지역, 경상남도의 창녕, 하동, 함양의 3개 지역, 강원도의 양양, 인제의 2개 지역, 충청북도의 괴산, 전라북도의 남원을 포함하여 총 11개의 송이 산지를 대상으로 1994년부터 1997년까지 산지별로 $3{\sim}8$개의 균환에서, 그리고 각 균환마다 2개의 자실체를 채집하여 6개의 primer를 이용하여 Inter Simple Sequence Repeat Polymerase Chain Reaction(I-SSR PCR)법을 이용하여 자실체의 유전적 특성을 조사하였다. 그 결과 총 131개의 DNA band가 재현성 있게 나타났다. 또한 산지간의 유연관계를 살펴보기 위하여 Nei의 genetic distance를 이용하여 UPGMA tree를 작성하였다. I-SSR PCR법을 이용하여 DNA를 분석한 결과, 산지간의 유전적 변이는 12.9%에 불과한 반면 산지 내 개체간 변이가 87.1%로 나타났다. 유집 분석 결과는 11개 송이 산지를 제 I 그룹(양양, 함양, 인제, 하동, 울진), 제 II 그룹(남원, 창녕, 청도), 제 III 그룹(고령), 제 IV 그룹(봉화, 괴산)의 4개 그룹으로 분류하였다. 송이의 유전적 다양성, 집단간의 유전적 차이를 나타내는 수치인 Fst 값이 0.13이므로 집단간의 유전적 변이를 어느 정도 나타낸다고 결론짓는다.

• 한국환경농학회지
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• 제13권1호
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• pp.98-110
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• 1994

논 주변에 서식하는 거미의 종류, 우점종, 월동상태, 증식상황, 이동상황, 년중 밀도변동상황 등을 파악하여 종합적 해충방제체계에 있어서 논거미의 보호 및 활용방안을 모색하고자, 경남 진주와 남해에서 1987년 12월부터 1988년 12월까지 논주변을 논둑, 보리밭, 휴한답, 본답 등으로 나누어 월 2${\sim}$4회 채집하고 종류와, 각 발육태별 밀도를 조사한 결과는 다음과 같다. 1. 거미는 총 10과 31속 34종이 채집되며, 논둑에서 34종, 보리밭에서 16종, 휴한답에서 17종, 본답에서 18종으로 나타나 논둑에서 종 구성이 다양하였다. 2. 진주와 남해의 각 채집장소별 논둑과 보리밭에서는 별늑대거미(Pardosa astrigera L. Koch), 휴한답에서는 황산적거미(Pirata subpiraticus (B. et S.)), 본답에서는 턱거미(Pachygnatha clercki Sunduvall)로 나타났다. 3. 논 주변 거미의 서식장소, 월동태, 거미줄 유무등 생태학적 특성과 과(科)(Family) 또는 속(屬)(Genera) 수준의 분류학적 특징으로 다음과 같은 9개의 거미군(Group)으로 분류할 수 있었다. Group 1 - 부이표늑대거미류(Pirata spp.); Group 2 - 턱거미류(Pachygnatha clercki); Group 3 - 소형정주성거미류(Theridiidae, Erigonidae, Linypiidae); Group 4 - 갈거미류(Tetragnatha spp.); Group 5 - 황닷거미류(Dolomedes surfureus); Group 6 - 긴마디늑대거미류(Pardosa spp.). Group 7 - 깡충거미류(Salticidae); Group 8 - 게거미류(Thomisidae); Group 9 - 염낭거미류(Clubionidae); 4. 9개 거미군 중 1-5군은 호습성 거미류로서 본 답기에 벼해충의 중요한 천적으로 여겨지며, 6-9군은 건조한 곳을 선호하는 거미류로서 논둑에서 월동중인 애멸구와 끝동매미충의 천적으로서 역할이 클 것으로 인식되었다.