• Clean Technology
• /
• v.24 no.4
• /
• pp.348-356
• /
• 2018

The adsorption equilibria of oxygen, nitrogen and argon on carbonaceous adsorbent with slit-shaped and randomly etched graphite (REG) pores were calculated by molecular simulation method. Reliable models of adsorbents and adsorbates for adsorption equilibria are important for the correct design of industrial adsorptive separation processes. At the smallest physical pore of $5.6{\AA}$, only oxygen molecules were accommodated at the center of the slit-shaped pore, and from $5.9{\AA}$ nitrogen and argon molecules could be accommodated in the pores. Slit pores showed higher adsorption capacity compared with REG pores with same averaged reenterance pore size due to dead volume and inaccessible volume in defected pores. And it was shown the adsorption capacities of oxygen and argon was same in larger pore size. From calculated adsorption isotherms at 298 K it showed that the adsorption capacity ratio of oxygen to nitrogen is increased as pressure is increased.

• Molecules and Cells
• /
• v.42 no.1
• /
• pp.56-66
• /
• 2019

Histidine triad nucleotide-binding protein (HINT) is a member of the histidine triad (HIT) superfamily, which has hydrolase activity owing to a histidine triad motif. The HIT superfamily can be divided to five classes with functions in galactose metabolism, DNA repair, and tumor suppression. HINTs are highly conserved from archaea to humans and function as tumor suppressors, translation regulators, and neuropathy inhibitors. Although the structures of HINT proteins from various species have been reported, limited structural information is available for fungal species. Here, to elucidate the structural features and functional diversity of HINTs, we determined the crystal structure of HINT from the pathogenic fungus Candida albicans (CaHINT) in complex with zinc ions at a resolution of $2.5{\AA}$. Based on structural comparisons, the monomer of CaHINT overlaid best with HINT protein from the protozoal species Leishmania major. Additionally, structural comparisons with human HINT revealed an additional helix at the C-terminus of CaHINT. Interestingly, the extended C-terminal helix interacted with the N-terminal loop (${\alpha}1-{\beta}1$) and with the ${\alpha}3$ helix, which appeared to stabilize the dimerization of CaHINT. In the C-terminal region, structural and sequence comparisons showed strong relationships among 19 diverse species from archea to humans, suggesting early separation in the course of evolution. Further studies are required to address the functional significance of variations in the C-terminal region. This structural analysis of CaHINT provided important insights into the molecular aspects of evolution within the HIT superfamily.

• Natural Product Sciences
• /
• v.27 no.1
• /
• pp.54-59
• /
• 2021

Bergenia ciliata (Family: Saxifragaceae) is a folklore remedy for the treatment of various ailments in Asian countries. Bergenin (1) has been isolated as an active constituent in many studies, however, the amount of bergenin has not been determined in all parts of the plant. A simple RP-HPLC method was developed to determine the amount of bergenin in methanol extracts of leaves, rhizomes and roots of the plant. Separation was achieved on an Agilent Eclipse XDB-C18 column maintained at 25 ℃ using isocratic solvent system (water: methanol: acetic acid; 62.5:37:0.5 v/v/v) adjusted at pH 2 0 at a flow rate of 1.0 mL/min. and detected at 275 nm. Correlation coefficient (0.9952) showed linearity of concentration (5-200 ㎍/mL) and response. The values of LOD (0.00947 ㎍/mL) and LOQ (0.02869 ㎍/mL) indicated that method was sensitive. The recovery of bergenin was 99.99-100% indicating accuracy of method. The methanol extract of rhizomes contained higher amount of bergenin (19.4%) than roots (9.2%) and leaves (6.9%). It is concluded that methanol extract of rhizomes is a better source of bergenin than other parts of the plant. The findings are useful for standardization of bergenin containing extracts and herbal preparations.

• Journal of Radiopharmaceuticals and Molecular Probes
• /
• v.6 no.2
• /
• pp.75-91
• /
• 2020

[^99mTc]Tc-Hexamethylpropylene amine oxime (HMPAO) is currently used as a regional cerebral blood flow imaging agent for single photon emission computed tomography (SPECT). The HMPAO ligand exists in two isomeric forms: d,l and meso showing different properties in vivo. Later studies indicated that brain uptake patterns of ^99mTc-complexes formed from separated enantiomers differed. Separation of enantiomers is difficult by fractional crystallizations method. Usually, the substance is obtained in low chemical yield in a time-consuming procedure. Furthermore, the final product still contains some impurity. So we have developed new efficient route for synthesis of R,R- and S,S-HMPAO enantiomeric compounds in 6-steps. Nucleophilic substitution (S_N2) reactions of 2,2-dimethylpropane-1,3-diamine either with S- (1a) or R-methyl2-chloropropanoate (1b) were performed to produce compounds R,R- (2a) or S,S-isomer (2b) derivatives protected with benzylchloroformate (Cbz), respectively. And then Weinreb amide and methylation reaction using Grignard reagent, oxime formation with ketone group and deprotectiion of Cbz group by hydrogenolysis gave S,S- (7a) or R,R-HMPAO (7b), respectively. Entaniomeric compounds were synthesied with high yield and purity without any undesired product. The 7a or 7b kits containing 10 ㎍ SnCl₂-2H₂O were labeled with ^99mTc with high radiolabeling yield (90%).

• Macromolecular Research
• /
• v.17 no.10
• /
• pp.757-762
• /
• 2009

The micro domain structures and crystallization behavior of the binary blends of poly(methyl methacrylate)-b-poly(pentafluorostyrene)-b-poly(methyl methacrylate) (PMMA-PPFS-PMMA) triblock copolymer with a low molecular weight poly(vinylidene fluoride) (PVDF) were investigated by small-angle X-ray scattering (SAXS), small-angle light scattering (SALS), transmission electron microscopy (TEM), optical microscopy, and differential scanning calorimetry (DSC). A symmetric, PMMA-PPFS-PMMA triblock copolymer with a PPFS weight fraction of 33% was blended with PVDF in N,N-dimethylacetamide (DMAc). In the wide range of PVDF concentration between 10.0 and 30.0 wt%, PVDF was completely incorporated within the PMMA micro domains of PMMA-PPFS-PMMA without further phase separation on a micrometer scale. The addition of PVDF altered the phase morphology of PMMA-PPFS-PMMA from well-defined lamellar to disordered. The crystallization of PVDF significantly disturbed the domain structure of PMMA-PPFS-PMMA in the blends, resulting in a poorly-ordered morphology. PVDF displayed unique crystallization behavior as a result of the space constraints imposed by the domain structure of PMMA-PPFS-PMMA. The pre-existing microdomain structures restricted the lamellar orientation and favored a random arrangement of lamellar crystallites.

• Korean Journal of Veterinary Research
• /
• v.31 no.2
• /
• pp.217-222
• /
• 1991

Most progesterone enzyme immunoassays(EIA) are used liquid phase double-antibody separation. These methods consume considerable time and reagents because of the requirements for several washing and centrifugation steps involving the reactants. Because of there several problems, we were prompted to develop an effective EIA system by the use of higher titer of progesterone antiserum free of anti-bovine serum albumin antibodies (anti-BSA). The results obtained were as follows. 1. The antibody of progesterone antiserum was high as $1.5{\times}10^5$. 2. Percent activity bound of progesterone antiserum was about 77 at a dilution to $5{\times}10^3$ times. 3. Progesterone antiserum was contained a large amount of anti-BSA antibodies. 4. The anti-BSA was completely absorbed by using of polymerised BSA. 5. The molecular weight of albumin polymer (polymerised BSA) obtained by using 2.5% glut. araldehyde was $5{\times}10^5$.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.58 no.4
• /
• pp.388-392
• /
• 2013

The proteins from functional rice cultivars (Nogwonchalbyeo, Giant embryonic, Arhyangchalbyeo, and Goamibyeo) and general white rice were extracted and separated using two-dimensional (2D) gel electrophoresis. A wide variation in the molecular weight (MW) and pH range of the expressed proteins in rice samples were observed. The green-kerneled rice (Nogwonchalbyeo) exhibited proteins with MW of 9-57 kDa and appeared at a pH range of 4-7. The Giant embryonic contained proteins with MW of 31-63 kDa and a pH range of 5-6. The aromatic glutinous rice (Arhyangchalbyeo) showed proteins with MW of 24-28 and pH of 5.8-6.8. The high-amylose rice (Goamibyeo) exhibited proteins with MW of 3-63 and pH of 5.2-5.6. The identified proteins uniquely found and highly expressed in each cultivar may have a significant role on rice functionality. The results illustrate that the 2D gel electrophoresis is a valuable method in the determination of the protein expression profiles in functional rice grains and may be useful in the identification of specific marker proteins associated with the functional property of rice.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.15 no.6
• /
• pp.511-517
• /
• 2002

The complex 1 $([Cp*Fe(CO)_2]_2-(\mu-CH=CH-CH=CH))$ which have butadiene as a bridge were synthesized from $Cp*(CO)_2FeK$ and cis-3,4-dichlorocyclobutene. The derivatives of complex 1 where one or two carbonyl groups are replaced by phosphine ligands have been prepared by photochemical substitution. The new derivatives $([Cp*Fe(L)_2]_2-(\mu-CH=CH-CH=CH))$ where L = $(Ph_2PCH_2CH_2PPh_2)$ and $([Cp*Fe(CO)(L)]_2-(\mu-CH=CH-CH=CH))$ where L : $PPh_3$ have been characterized from $^^1H-$, $^^13C-$,$^^31P-NMR$ and elemental analysis. Obtained complexes have been studied in electrochemical experiment and UV/VIS-near-IR. The mixed-valence radical cation forms of complex 2, 3 species were found to be delocalized as the Class III. Based on the separation of the waves ($\triangle E$ : 0.470 ~ 0.605 V), the efficiency of electronic communication between two metal centers of cation species leading to stabilization relative to neutral species. The phosphine-substitute complexes (2, 3) displays two reversible oxidation waves and oxidation state of metal centers-dependent color change, electrochromism, was observed from yellow to orange and deep blue in methylene chloride.

• Preventive Nutrition and Food Science
• /
• v.2 no.4
• /
• pp.316-320
• /
• 1997

Phenolic acids are regarded as harmful materials in food and environment science but recently, as useful materials, and thus adsorption is recommended as an effective separation technique to recover or remove phenolic acids from diluted solution. If the adsorbed phenolic compounds were useful materials, the materials should be recovered through desorption. Desorption using supercritical carbon dioxide(SC-$CO_2$) was tried to separate food-borne phenolic acids from charcoal in single solute system. In the comparisons of desorption amounts, gallic acid had the lowest lolubiligy to SC-$CO_2$. Gallic acid has more hydroxy functional groups than the other phenolic acids, which was immiscible with nonpolar SC-$CO_2$. Ferulic acid was yielded more than p-coumaric acid, because ferulic acid had much bigger molecular weight, which was affected more by van der Waas force. It was found that the most affecting factor on desorption amounts was the solubility of phenolic acids to SC-$CO_2$. The second affecting factor was van der Waals force. Response surface methodology(RSM) was conducted to read the trend of desorption. Increasing density of SC-$CO_2$ raised solubility of phenolic acids.

• BMB Reports
• /
• v.28 no.4
• /
• pp.359-362
• /
• 1995

The highly polymorphic variable number of tandem repeat (VNTR) loci in the human genome are informative markers for the genetic characterization of individuals in the paternity test and forensic science as well as for the study of human disease. In this study, VNTR loci D1S80 and D2S123 have been amplified by PCR and the amplified length polymorphic alleles were detected with a discontinuous vertical PAGE system and silver staining. For explicit DNA typing, PCR optimization, in which amplification efficiencies are similar over a wide range of allele sizes, non-specific amplifications are minimal, and new longer alleles have high amplification efficiency, has been performed by changing the PCR reaction buffer composition and thermal cycling conditions. It turned out that adding an appropriate amount of Tween 20 and NP40 to the PCR reaction buffer and raising the annealing temperature to $68^{\circ}C$ in thermal cycling made it possible for optimal VNTR loci amplification. A modified PAGE system for VNTR separation was established. Under these conditions, new longer alleles in the 01580 locus were discovered and 025123 pattern changes in colorectal tumors were observed. These technical tips are valuable for detecting various amplified fragment length polymorphisms.