• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.293-296
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• 2002

Hyperosmotic pressure increased specific antibody productivity ($q_{Ab}$) of recombinant CHO cells (SH2-0.32) while it depressed cell growth. Thus, the use of hyperosmolar medium did not increase the maximum antibody concentration substantially. To overcome this drawback, the feasibility of biphasic culture strategy was investigated. In the biphasic culture, cells were first cultivated in the standard medium with physiological osmolality(294 mOsm/kg) for cell growth. When cells reached the late exponential phase of growth, the spent standard medium was replaced with the fresh hyperosmolar medium (522 mOsm/kg) for antibody production. The ($q_{Ab}$) in growth phase with the standard medium was 2.1 ${\mu}g/10^6cell/day$ while the ($q_{Ab}$) in antibody production phase with the hyperosmolar medium (522 mOsm/kg) was 11.1 ${\mu}g/10^6cell/day$. Northern blot analysis showed a positive relationship between the relative contenet of Ig mRNA and ($q_{Ab}$), indicating that transcriptional regulation was involved in the response of rCHO cells to hyperosmotic pressure. Due to the enhanced ($q_{Ab}$) and increased cell concentration in biphasic culture, the maximum antibody concentration obtained in biphasic culture with 522 mOsm/kg medium exchange was 161% higher than that obtained in batch culture with the standard medium. Taken together, simple biphasic culture strategy based on hyperosmotic culture for improved foreign protein production from rCHO cells is effective in improving antibody production of rCHO cells.

• Tuberculosis and Respiratory Diseases
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• 제45권2호
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• pp.416-420
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• 1998

저자들은 기관지결핵의 후유증으로 좌주기관지 협착이 있었던 환자가 이상성 기류유량곡선을 보인 후 금속스텐트 삽입후 교정되었다가 스텐트 삽입 2개월 후부터 육아종형성에 따른 좌주기관지의 재협착이 나타나 다시 기류유량곡선상 이상성 기류유량곡선을 보인 증례를 경험하였기에 보고하는 바이다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.161-162
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• 2012

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2002년도 추계총회 및 연구발표회 초록집
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• pp.203.1-203
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• 2002

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1945-1950
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• 2011

The pyridinolysis of methyl phenyl phosphinic chloride is investigated kinetically in acetonitrile at -20.0 $^{\circ}C$. The Hammett and Br${\o}$nsted plots for substituent X variations in the nucleophiles are biphasic concave downwards with a break point at X = H, and unusual positive ${\rho}_X$ (= 2.94) and negative ${\beta}_X$ (= -0.48) values are obtained for the strongly basic nucleophiles. A stepwise mechanism with a rate-limiting step change from bond breaking for the weakly basic pyridines to bond formation for the strongly basic pyridines is proposed on the basis of biphasic concave downward Hammett and Br${\o}$nsted plots. Unusual positive ${\rho}_X$ and negative ${\beta}_X$ values are rationalized by the isokinetic relationship. The pyridinolyses and anilinolyses of four $R_1R_2$P(=O)Cl-type substrates, dimethyl, diethyl, methyl phenyl, and diphenyl phosphinic chlorides in acetonitrile are compared to obtain systematic information on phosphoryl transfer reaction mechanism. The combination of the two ligands, Me and Ph, shows unexpected kinetic results for both the anilinolysis and pyridinolysis: greatest magnitude of $k_H/k_D$ (= 2.10) involving deuterated anilines $[XC_6H_4NH_2(D_2)]$ for the anilinolysis, and exceptionally fast rate and biphasic concave downward free energy correlation for the pyridinolysis.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1138-1142
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• 2011

Kinetic studies for the reactions of Y-aryl phenyl chlorothiophosphates with X-pyridines have been carried out in acetonitrile at $35.0^{\circ}C$. The Hammett and Bronsted plots for substituent X variations in the nucleophiles are biphasic concave upwards with a break point at X = 3-Ph, while the Hammett plots for substituent Y variations in the substrates are biphasic concave downwards (and partially upwards) with a break point at Y = H. The signs and magnitudes of the cross-interaction constant (${\rho}_{XY}$) are strongly dependent upon the nature of substituents, X and Y. The proposed mechanism is a stepwise process with a rate-limiting step change from bond breaking with the weaker electrophiles to bond formation with the stronger eletrophiles. The nonlinear free energy correlations of biphasic concave upward plots for substituent X variations in the nucleophiles are rationalized by a change in the attacking direction of the nucleophile from a backside with less basic pyridines to a frontside attack with more basic pyridines.

• Journal of Periodontal and Implant Science
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• 제35권4호
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• pp.1097-1108
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• 2005

The present study was to determine the influence of micro-macro biphasic calcium phosphate(MBCP) on proliferation and differentiation of human marrow-derived mesenchymal stem cells. Primary stem cells were cultured from bone marrow and 3-4 passaged cells were used. This study tested the proliferative effects by cell counting. Collagen sythensis, alkaline phosphatase activity, expression of osteocalcin and bone sialoprotein by Western blot analysis were evaluated. The cellular proliferation of ASC was not influenced by MBCP. Collagen synthesis of ASC cultured on MBCP significantly increased at 5th and 7th days(p<0.05). The ALP activity in ASC cultured on MBCP significantly increased at 5th and 7th days(p<0.05). The expression of OC and BSP incresaed in ASC cultured on MBCP. These results suggest that MBCP may stimulates the osteoblastic activity of ASC.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제42권
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• pp.34.1-34.7
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• 2020

Purpose: The purpose of this study was to evaluate the influence of biodegradable polycaprolactone membrane on new bone formation and the biodegradation of biphasic alloplastic bone substitutes using animal models. Materials and methods: In this study, bony defect was formed at the canine mandible of 8 mm in diameter, and the defects were filled with Osteon II. The experimental groups were covered with Osteoguide as barrier membrane, and the control groups were closed without membrane coverage. The proportion of new bone and residual bone graft material was measured histologically and histomorphometrically at postoperative 4 and 8 weeks. Results: At 4 weeks, the new bone proportion was similar between the groups. The proportion of remaining graft volume was 27.58 ± 6.26 and 20.01 ± 4.68% on control and experimental groups, respectively (P < 0.05). There was no significant difference between the two groups in new bone formation and the amount of residual bone graft material at 8 weeks. Conclusion: The biopolymer membrane contributes to early biodegradation of biphasic bone substitutes in the jaw defect but it does not affect the bone formation capacity of the bone graft.

• 한국결정성장학회지
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• 제21권4호
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• pp.169-174
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• 2011

합성된 biphasic calcium phosphate(BCP) 분말의 나노크기 생분해성 거동은 X-선 회절 분석방법, 격자 매개변수 및 전계방출형 주사전자현미경을 통해 특성평가 하였다. BCP 분발은 공침반응 및 하소과정을 통해 합성하였고, 합성된 분발은 행크 용액 (pH = 7.4, $36.5^{\circ}C$)을 이용하여 3주 동안 in vitro 시험 하였다 분해 시험(in vitro) 후, BCP 단위포의 매개변수는 a 및 c축의 불규칙한 변화와 비슷한 격자 왜곡 및 팽창 거동을 보였다.

• 한국결정성장학회지
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• 제22권2호
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• pp.99-104
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• 2012

BCP(biphasic calcium phosphate) 분말을 제조하기 위하여 $Ca(NO_3)_2{\cdot}4H_2O$, $(NH_4)_2HPO_4$를 출발 물질로 공침법(co-precipitation process)을 이용하여 합성하였다. 합성된 분말의 열처리 전 후의 HAp(Hydroxyapatite)/${\beta}$-TCP(${\beta}$-Tricalcium phosphate) 결정상 비율 및 분광학적 특성을 XRD 및 FT-IR를 이용하여 분석하였다. BCP 분말의 생체활성 거동을 평가하기 위하여 Hanks' Balanced Salt Solution(HBSS)에 침적시켜 시간에 따라 형상, 이온농도의 변화 및 결정상을 분석한 결과 낮은 결정화도의 HAp가 생성됨을 확인하였다. BCP분말의 세포독성 평가에서도 대조군에 비하여 세포성장률이 우수함을 관찰하였다.