• Journal of Integrative Natural Science
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• v.8 no.2
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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.

• Journal of Integrative Natural Science
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• v.5 no.3
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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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• v.53 no.3
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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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• v.11 no.2
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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.

• Journal of Global Scholars of Marketing Science
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• v.11
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• pp.129-146
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• 2003

This study explores whether a NBD type of model can be applied to characterize the underlying frequency distribution of online consumer's visit behavior. In this study, the following two research questions are addressed: (1) How can we characterize the underlying distribution pattern(s) of the number of repeat i i visits to a site? (2) How can consumer's Internet usages and his/her demographics affect the average number of visits to the site? Through the empirical investigation, this study found that NBD models are directly applicable to characterize the underlying distribution of visit frequency on the Internet. Furthermore, this study addresses some managerial implications for understanding how site visits are determined. Especially this study highlights the relationship between repeated visits and the visitors' Internet Usages and demographics. The proposed models are estimated and validated by online panel data that covers more than 1000 different sites and has 800,000 observations.

• Journal of Integrative Natural Science
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• v.5 no.1
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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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• v.13 no.1
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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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• v.29 no.8
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• pp.1601-1604
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• 2008

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2809-2812
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• 2011

• Journal of Korean Society on Water Environment
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• v.23 no.5
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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.