• 한국동물위생학회지
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• 제28권4호
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• pp.393-405
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• 2005

In prion pathogenesis, the structural conversion of the cellular prion protein $(PrP^c)$ to its abnormal isomer $(PrP^{Sc})$ is believed to be a major event. The susceptibility or resistance to natural sheep scrapie is associated with polymorphisms of host PrP gene (PRNP) at amino acid residues 136, to a lesser extent 154. The 112 residue in ovine PrP displays a natural polymorphism, Methionine to Threonine, which has not been thoroughly investigated. However the cell-free conversion assay showed that ARQ with Thr112 $(T_{112}ARQ)^{1)}$ presents lower convertibility to $PrP^{Sc}$than wild type ARQ $(M_{112}ARQ)$ [1] In this study we generated ovine recombinant PrPs of 112 allelic variants by metal chelate affinity chromatography and cation exchange chromatography. The final purity of the ovine PrP ARQ was more than $95\%$. These variants showed similar immunoreactivity against anti-PrP monoclonal antibodies in Western blot and ELISA. The refolded $M_{112}ARQ$ and $M_{112}ARQ$ presented the secondary structural content to similar extent via CD spectroscopy analysis. The inherited structural features of $M_{112}ARQ$ and $M_{112}ARQ$ under the different biophysical conditions are in the middle of investigation.

• Biomolecules & Therapeutics
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• 제31권2호
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• pp.141-147
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• 2023

Antibiotic resistance has emerged as a global threat to modern healthcare systems and has nullified many commonly used antibiotics. β-Lactam antibiotics are among the most successful and occupy approximately two-thirds of the prescription antibiotic market. They inhibit the synthesis of the peptidoglycan layer in the bacterial cell wall by mimicking the D-Ala-D-Ala in the pentapeptide crosslinking neighboring glycan chains. To date, various β-lactam antibiotics have been developed to increase the spectrum of activity and evade drug resistance. This review emphasizes the three-dimensional structural characteristics of β-lactam antibiotics regarding the overall scaffold, working mechanism, chemical diversity, and hydrolysis mechanism by β-lactamases. The structural insight into various β-lactams will provide an in-depth understanding of the antibacterial efficacy and susceptibility to drug resistance in multidrug-resistant bacteria and help to develop better β-lactam antibiotics and inhibitors.

• Journal of Microbiology and Biotechnology
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• 제9권1호
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• pp.1-8
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• 1999

Most carbohydrates exist in nature in an insoluble state, which reduces their susceptibility towards various carbohydrases. Accordingly, they require intensive pretreatment for structural modification to enhance an enzyme reaction. The direct conversion of insoluble carbohydrates has distinct advantages for special types of reaction, especially exo-type carbohydrase; however, its application is limited due to structural constraints. This paper introduces two novel heterogeneous enzyme reaction systems for direct conversion of insoluble carbohydrates; one is an attrition coupled enzyme reaction system containing attrition-milling media for enhancing the enzyme reaction, and the other is a heterogeneous enzyme reaction system using extruded starch as an insoluble substrate. The direct conversion of typically insoluble carbohydrates, including cellulose, starch, and chitin with their corresponding carbohydrases, including cellulase, amylase, chitinase, and cyclodextrin glucanotransferase, was carried out using two proposed enzyme reaction systems. The conceptual features of the systems, their reaction characteristics and mechanism, and the industrial applications of the various carbohydrates are analyzed in this review.

• Genomics & Informatics
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• 제11권3호
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• pp.149-154
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• 2013

Liver enzyme elevations, as an indicator of liver function, are widely associated with metabolic diseases. Genome-wide population-based association studies have identified a genetic susceptibility to liver enzyme elevations and their related traits; however, the genetic architecture in childhood remains largely unknown. We performed a genome-wide association study to identify new genetic loci for liver enzyme levels in a Korean childhood cohort (n = 484). We observed three novel loci (rs4949718, rs80311637, and rs596406) that were multiply associated with elevated levels of alanine transaminase and aspartate transaminase. Although there are some limitations, including genetic power, additional replication and functional characterization will support the clarity on the genetic contribution that the ST6GALNAC3, ADAMTS9, and CELF2 genes have in childhood liver function.

• Structural Engineering and Mechanics
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• 제81권3호
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• pp.281-292
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• 2022

This study aimed to analyze the dynamic punching shear performance of slab-column joints under cyclic loads with the use of double-hooked end (5D) steel fibers. Structural systems such as slab-column joints are widely found in infrastructures. The susceptibility to collapse of such structures when submitted to seismic loads is highly dependent on the structural performance of the slab-column connections. For this reason, the punching capacity of reinforced concrete (RC) structures has been the subject of a great number of studies. Steel fibers are used to achieve a certain degree of ductility under seismic loads. In this context, 5D steel hooked fibers provide high levels of fiber anchoring, tensile strength and ductility. However, only limited research has been carried out on the performance under cyclic loads of concrete structural members containing steel fibers. This study covers this gap with experimental testing of five different full-scale subassemblies of RC slab-column joints: one without punching reinforcement, one with conventional punching reinforcement and three with 5D steel fibers. The subassemblies were tested under cyclic loading, which consisted of applying increasing lateral displacement cycles, such as in seismic situations, with a constant axial load on the column. This set of cycles was repeated for increasing axial loads on the column until failure. The results showed that 5D steel fiber subassemblies: i) had a greater capacity to dissipate energy, ii) improved punching shear strength and stiffness degradation under cyclic loads; and iii) increased cyclic loading capacity.

• 대한화학회지
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• 제56권2호
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• pp.217-227
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• 2012

Syntheses of some novel oxomolybdenum(V) and dioxomolybdenum(VI) complexes with an azo dye methoxyphenolazoantipyrine (HL) derived from 4-aminoantipyrine and 2-methoxyphenol are reported. The complexes have been characterized by elemental analyses, molar conductance, magnetic susceptibility data, IR, UV-Vis, $^1H$ NMR, EPR and FAB mass spectral studies. The physicochemical studies and spectral data indicate that HL acts as a bidentate chelating ligand. The complexes have the general formulae [$MoO(HL)XCl_2$] and [$MoO_2(HL)XCl$],where X=Cl, NCS or $NO_3$. All the complexes are found to have distorted octahedral geometry. Structural and morphological characterization of the complexes [$MoO(HL)Cl_3$](1) and [$MoO_2(HL)Cl_2$](4) before and after gamma ray irradiation,was performed by X-ray diffraction and scanning electron microscopy( SEM).The ligand and the complexes were screened for their possible antimicrobial activities.

• Structural Engineering and Mechanics
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• 제48권2호
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• pp.207-220
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• 2013

In this study, the vulnerability of two existing asymmetric steel building frames to Progressive Collapse (PC) is assessed. The buildings have different frame systems, steel sections and number of stories (nine and six). An alternate path method (APM) with a linear static analysis (LS) is carried out according to General Services Administration (GSA) 2003 guidelines. The Demand Capacity Ratio (DCR) of each primary element (beams and columns) is given with its specific details for all frames. The results show that the nine-story building with a dual frame system (moment frame with bracing system) has a lower susceptibility and greater resistance to PC than the six-story building with a simple building frame system (gravity system with bracing system). Implementing built-up box-shaped sections for columns is a better choice than using built-up I-shaped sections because there is no weak axis for the box section.

• Journal of Microbiology and Biotechnology
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• 제28권10호
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• pp.1716-1722
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• 2018

Immunosuppressive drugs are used to make the body less likely to reject transplanted organs or to treat autoimmune diseases. In this study, five immunosuppressive drugs including two glucocorticoids (dexamethasone and prednisolone), one calcineurin inhibitor (cyclosporin A), one non-steroid anti-inflammatory drug (aspirin), and one antimetabolite (methotrexate) were tested for their effects on viral proliferation using feline foamy virus (FFV). The five drugs had different cytotoxic effects on the Crandell-Ress feline kidney (CRFK) cells, the natural host cell of FFV. Dexamethasone-pretreated CRFK cells were susceptible to FFV infection, but pretreatment with prednisolone, cyclosporin A, aspirin, and methotrexate showed obvious inhibitory effects on FFV proliferation, by reducing viral production to 29.8-83.8% of that of an untreated control. These results were supported by western blot, which detected viral Gag structural protein in the infected cell lysate. As our results showed a correlation between immunosuppressive drugs and susceptibility to viral infections, it is proposed that immune-compromised individuals who are using immune-suppressive drugs may be especially vulnerable to viral infection originated from pets.

• Bulletin of the Korean Chemical Society
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• 제20권9호
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• pp.1005-1009
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• 1999

Wustite with NaCl structure is successfully synthesized in a quartz tube sealed under vacuum ( ≒1×10 -3 torr). Hematite in an evacuated quartz tube progressively loses oxide ion at 1373 K. XRD patterns disclose that α-Fe2O3 is transformed into the Fe3O4 after heat treatment at 1373 K for 32 h, and the poorly crystallized FeO is appeared after heat treatment for 48 h. Finally, α-Fe2O3 is completely transformed into the well crystallized Fe 0.935O after heat treatment for 84 h. The electrical resistivity, ac-susceptibility measurement, Mossbauer spectroscopy, and x-ray absorption spectroscopy corroborate the structural phase transition on the iron oxides prepared in a sealed quartz tube depending on the heating time at 1373 K.

• Bulletin of the Korean Chemical Society
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• 제21권12호
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• pp.1187-1192
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• 2000

Ternary (Mo-Ru-Pd) and binary (Mo-Ru, Mo-Pd) alloys have been prepared using an Ar arc melting furnace. Mo and the noble metals, Ru and Pd, are the constituents of metallic insoluble residues, which were found in the early days of post-irradiation studies on uranium oxide fuels. In the present study, the structure of the alloys was evaluated using a powder X-ray diffractometer. Unit cell parameters were determined by least squares refinements of powder X-ray diffraction data. Scanning electron microscopic analyses of the surface of the alloys indicated that surface morphology was dependent on the crystallographic structure as well as its composition. Measurements of the magnetic susceptibility of the alloys showed evidence of superconducting transition from 3 to 9.2 K. Among the ternary and binary alloys, the ${\sigma}-phase$ showed the highest superconducting transition temperature,~9.2 K.