• 통합자연과학논문집
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• 제8권2호
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• pp.111-116
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• 2015

Liquid chromatographic enantiomer separation of ${\alpha}$-amino acid esters as nitrobenzoxadiazole (NBD) derivatives was performed using several chiral stationary phases (CSPs) based on polysaccharide derivatives under fluorescence detection. For enantiomer separation by normal HPLC, the non-aqueous derivatization method of ${\alpha}$-amino acid esters for NBD analytes was introduced. Among the six CSPs used in this study, the performance of Chiralpak IA was superior for enantiomer resolution of NBD derivatives of several ${\alpha}$-amino acid methyl esters. Also the convenient analytical method using polysaccharide-derived CSPs developed in this study was applied to determine the optical purity of ${\alpha}$-amino acids esters. It was investigated that the enantiomeric impurity levels of 0.02-1.73% were found after determination of enantiomeric purities of several commercially available L-amino acid methyl esters. It is expected to be quite useful for enantiomer separation of other ${\alpha}$-amino acid esters as NBD derivatives by normal HPLC.

• 통합자연과학논문집
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• 제5권3호
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• pp.190-194
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• 2012

Human P-gp is one of the protein responsible for the multidrug resistance (MDR) develpment. MDR is a major cause of the cancer chemotherapy. In this paper, we performed homology modeling, docking study of papayriferic acid into the P-gp nucleotide binding domain (NBD2). For human P-gp, X-ray crystal structure is not known yet. We developed homology model for human NBD2 using HlyB ABC transporter structure (PDB code: 1XEF, resolution 2.5 ${\AA}$). Docking study was performed using Autodock. Docking result was analyzed, which shows that ligand docks into steroid binding site and interacts through hydrophobic and hydrophilic interactions.

• Parasites, Hosts and Diseases
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• 제53권3호
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• pp.335-339
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• 2015

Cryptosporidium andersoni ATP-binding cassette (CaABC) is an important membrane protein involved in substrate transport across the membrane. In this research, the nucleotide binding domain (NBD) of CaABC gene was amplified by PCR, and the eukaryotic expression vector of pEGFP-C1-CaNBD was reconstructed. Then, the recombinant plasmid of pEGFP-C1-CaNBD was transformed into the mouse intestinal epithelial cells (IECs) to study the iron transportation function of CaABC. The results indicated that NBD region of CaABC gene can significantly elevate the transport efficiency of $Ca^{2+}$, $Mg^{2+}$, $K^+$, and $HCO_3{^-}$ in IECs (P<0.05). The significance of this study is to find the ATPase inhibitors for NBD region of CaABC gene and to inhibit ATP binding and nutrient transport of CaABC transporter. Thus, C. andersoni will be killed by inhibition of nutrient uptake. This will open up a new way for treatment of cryptosporidiosis.

• Bulletin of the Korean Chemical Society
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• 제11권2호
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• pp.134-139
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• 1990

The hydrogenation catalyst precursors $[(L-L)Rh(NBD)]ClO_4\;(L-L=Fe({\eta}^5-C_5H_4PBu^t\;_2)_2,\;Fe({\eta}^5-C_5H_4PPhBu^t)_2$; NBD = norbornadiene) react with $H_2(1\;atm,\;30^{\circ}C$, MeOH) to yield $[(L-L)HRh({\mu}-H)_3RhH(L-L)]ClO_4$. These hydrido species are fluxional, and variable temperature NMR studies show the existence of a number of equilibria involving both fluxional and non-fluxional species. The synthesis, solution structures, and fluxional behaviors of these hydrides are described.

• 마케팅과학연구
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• 제11권
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• pp.129-146
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• 2003

본 연구는 소비자들의 선택모형에서 널리 사용된 NBD (Negative Binomial Distribution) 타입의 계랑적 모델 접근법이 온라인 상에서 소비자들이 특정한 기업의 웹사이트를 방문하는 행위를 설명하는데 적용될 수 있는지를 탐구한다. 본 연구에서는 다음의 두 가지 연구 주제를 다루고 있다. 첫째, 소비자들이 웹사이트를 반복하여 방문하는 행위의 빈도에 관한 분포를 확률적으로 규정하며, 둘째로는 그러한 소비자들의 반복된 이용빈도의 분포에 소비자들의 일반적인 인터넷 사용패턴과 인구 통계적인 변수들이 어떤 영향을 미치는지를 조사하고 있다. 일련의 실증적 분석을 통하여, 이 논문은 마케팅의 선택모형 (Choice Model)들에서 널리 사용된 NBD 타입의 모댈들이 인터넷상의 사이트 방문빈도 연구에도 잘 적용될 수 있음을 보여주고 있다. 그리고 이 연구는 이러한 소비자들의 이용빈도에 관한 모델개발이 온라인 기업의 당면문제에 어떠한 영향을 미치는 지를 설명한다. 특히 본 연구는 반복된 이용빈도와 소비자들의 일반적인 인터넷사용 특징 및 인구 통계적인 변수들과의 상호관계를 규명했다. 본 연구에서 제시된 모델들을 추정하고 검정하기 위해 800,000번의 방문 기록과 1000개 이상의 상이한 방문사이트 수로 구성된 웹 패널 데이터를 사용하여 실증분석을 연구에서 제시하는 모델을 개발하고 검증하였다.

• 통합자연과학논문집
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• 제5권1호
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• pp.18-21
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• 2012

The resistance of tumour cells against cytotoxic drug is significant limitation in successful chemotherapeutic treatment of cancer. To date, no crystal structure is available for human P-gp. We developed homology model for human P-gp NBD2 by using coordinates of transporter associated protein (TAP1). Docking study was performed for 8-geranyl-chrysin (Flavonoids) inhibitor in the NBD2 model. Ligand-protein interactions were determined which indicates that the 8-geranyl chrysin shares two overlapping sites in the cytosolic domains of P-gp, the ATP site and a hydrophobic steroid-binding site.

• Advances in concrete construction
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• 제13권1호
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• pp.83-99
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• 2022

The two, NBD and SCB tests using gypsum circular discs each containing a single notch have been experimentally accomplished in a rock mechanics laboratory. These specimens have also been numerically modelled by a two-dimensional particle flow which is based on Discrete Element Method (DEM). Each testing specimen had a thickness of 5 cm with 10 cm in diameter. The specimens' lengths varied as 2, 3, and 4 cm; and the specimens' notch angles varied as 0°, 45° and 90°. Similar semi-circular gypsum specimens were also prepared each contained one edge notch with angles 0° or 45°. The uniaxial testing machine was used to perform the experimental tests for both NBD and SCB gypsum specimens. At the same time, the numerical simulation of these tests were performed by PFC2D. The experimental results showed that the failure mechanism of rocks is mainly affected by the orientations of joints with respect to the loading directions. The failure mechanism and fracturing patterns of the gypsum specimens are directly related to the final failure loading. It has been shown that the number of induced tensile cracks showing the specimens' tensile behavior, and increases by decreasing the length and angle of joints. It should be noted that the fracture toughness of rocks' specimens obtained by NBD tests was higher than that of the SCB tests. The fracture toughness of rocks usually increases with the increasing of joints' angles but increasing the joints' lengths do not change the fracture toughness. The numerical solutions and the experimental results for both NDB and SCB tests give nearly similar fracture patterns during the loading process.

• Bulletin of the Korean Chemical Society
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• 제29권8호
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• pp.1601-1604
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• 2008

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2809-2812
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• 2011

• 한국물환경학회지
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• 제23권5호
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• pp.600-606
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• 2007

Livestock wastewater containing concentrated organic matters and nutrients has been known as one of the major pollutants. It is difficult to apply the conventional activated sludge process to treat livestock wastewater because of high Non-biodegradable (NBD) matter and ammonia. The objectives of this study are to remove NBD matters including aromatic compounds and ammonia in livestock wastewater using Coagulation-Fenton oxidation-Zeolite (CFZ) processes and ascertain applicable feasibility in the field through pilot plant experiment. NBD matters and color remained in the treated water were removed over 92% by Fenton oxidation as the second treatment process. Ammonia was removed by over 99.5% in the zeolite ion exchange process as the last treatment method. From $UV_{254}$, $E_2/E_3$ ratio and GC/MS analyses of treated water at each process, the aromatic compound was converted to aliphatic and aromaticity was decreased. In pilot scale test, organics and ammonia removal efficiencies were not much different from the result of lab-scale test at various operation conditions. Furthermore, reaction time and dosage of Fenton reagent in pilot scale experiment reduced by 40 min and 50% rather than in lab-scale test. $BOD_5$, $COD_{Mn}$, SS, T-N and T-P of treated water in the pilot-scale experiment also met the effluent standards.