• Progress in Medical Physics
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• v.28 no.4
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• pp.135-143
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• 2017

Chemical Exchange Saturation Transfer (CEST) imaging is a method to detect solutes based on the chemical exchange of mobile protons with water. The solute protons exchange with three different patterns, which are fast, slow, and intermediate rates. The CEST contrast can be obtained from the exchangeable protons, which are hydroxyl protons, amine protons, and amide protons. The CEST MR imaging is useful to evaluate tumors, strokes, and other diseases. The purpose of this study is to review the mathematical model for CEST imaging and for measurement of the chemical exchange rate, and to measure the chemical exchange rate using a 3T MRI system on several amino acids. We reviewed the mathematical models for the proton exchange. Several physical models are proposed to demonstrate a two-pool, three-pool, and four-pool models. The CEST signals are also evaluated by taking account of the exchange rate, pH and the saturation efficiency. Although researchers have used most commonly in the calculation of CEST asymmetry, a quantitative analysis is also developed by using Lorentzian fitting. The chemical exchange rate was measured in the phantoms made of asparagine (Asn), glutamate (Glu), ${\gamma}-aminobutyric$ acid (GABA), glycine (Gly), and myoinositol (MI). The experiment was performed at a 3T human MRI system with three different acidity conditions (pH 5.6, 6.2, and 7.4) at a concentration of 50 mM. To identify the chemical exchange rate, the "lsqcurvefit" built-in function in MATLAB was used to fit the pseudo-first exchange rate model. The pseudo-first exchange rate of Asn and Gly was increased with decreasing acidity. In the case of GABA, the largest result was observed at pH 6.2. For Glu, the results at pH 5.6 and 6.2 did not show a significant difference, and the results at pH 7.4 were almost zero. For MI, there was no significant difference at pH 5.6 or 7.4, however, the results at pH 6.2 were smaller than at the other pH values. For the experiment at 3T, we were only able to apply 1 s as the maximum saturation duration due to the limitations of the MRI system. The measurement of the chemical exchange rate was limited in a clinical 3T MRI system because of a hardware limitation.

• Biomedical Science Letters
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• v.16 no.4
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• pp.229-238
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• 2010

Chicken Mx protein (cMx) induced interferon (IFN) is an antiviral protein to inhibit replication of RNA virus, particularly negative stranded RNA virus, through blockage of transfortation of viral RNA and proteins. In order to determine antiviral effects of cMx from different MHC haplotype chicken, we characterized cMx gene by studying on nucleotide sequencing, antiviral effects to Newcastle disease virus, VSV and MDV, and transcription activities. Three types of eMx genes (2,118 bp) were detected from the different MHC haplotype chickens [B19 (N), B15(F) and B21 (GSP)] chickens, which have showed different susceptible to Marek's disease (MD). Several amino acid substitutions were showed in the cMx. The amino acid 548 and 631 in the cMxs from N and F, chickens susceptible to MD, was Val and Asn which was important on antiviral effects, and showed in resistant cMx. Those in the cMx from GSP, chicken resistant to MD, were same that showed in susceptible cMx. Though every cMx transactivated the expression of the reporter gene, the transcription activation by resistant cMx from N and F was lower compared to that by susceptible cMx from GSP. The decease of the cell growth in the resistant cMx cloned cells was seen in comparison with another cMx clone cells. Replication of NDV and VSV was suppressed in the clones with resistant cMx from N and F. NMx258-transducted cells lack of antiviral effects, and NMx437 or NMx646-transducted cells was showed 60% of antiviral effects compared to NMx705. Mean death time (MDT) and hemaggutination (HA) titer to NDV was long and low in the eggs of N and F lines, but short and high in the egg of GSP line. Interestingly, strong suppression to NDV was observed in the clone with N-Mx and in the eggs of N line. However, the effects of Mx for replication of vvMDV1 have not been. Thus, resistant types of cMx, N- and F-Mx, have showed the anti-viral effects to only RNA virus including NDV and VSV, but not to DNA virus. Antiviral effects of cMx were required whole length of amino acid including Val and Asn in amino acid 548 and 631.

• The Korean Journal of Ecology
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• v.26 no.3
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• pp.135-142
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• 2003

Four legume plants showed better growth by the external nitrogen supply rather than the symbiotic nitrogen fixation only under salt additions. In case of Glycine max and Phaseolus angularis, total nitrogen contents decreased by high salinity level but their amino acid levels significantly increased with the increase of salt treatments and indicated high soluble-/insoluble-N ratios. Cassia tora and Albizzia julibrissin contained less amino acids than G. max and P. angularis but total N (esp. insoluble N fraction) increased with higher salt levels. Asparagine occurred as a main amino acid especially in G. max and P. angularis and can be seen as potential N-storage form in these plants. It might be play an important role for the osmoregulation mechanism under the saline condition. Meanwhile, to investigate what kinds of nitrogen sources are effective for overcoming salt stress on soybean plants, various N forms and concentrations (NH₄NO₃-N, NO₃-N, NH₄NO₃-N; 2.5 and 5 mM) were additionally supplied to the salt gradient medium. Soybean plants treated with NH₄NO₃-N showed the best growth up to 40 mM NaCl and NO₃- fed plants indicated good growth even at 80 mM NaCl treatments. Contrary to NH₄NO₃- and NO₃- fed plants, NH₄/sup +/- fed plants showed remarkable growth reduction and died by 40 and 80 mM NaCl treatments after the first harvest (15th day). Consequently, these results suggest that salt excluding and resistant capacities of soybean plants under NaCl treatments are increased in order of NH₄ - N, control, NO₃- N and NH₄NO₃- N depending on N concentration except NH₄- N treatments.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.1
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• pp.387-393
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• 2016

Background: CYP1A1 is a candidate gene for low-penetrance breast cancer susceptibility, as it plays an important role in the metabolism of carcinogens and estrogens. Purpose: The objective of this study was to assess the association between M2 (A2455G, Ile462Val) and M4 (C2453A, Thr461Asn) polymorphisms in CYP1A1 and breast cancer risk among Jordanian women and in subgroups stratified by menopausal status and smoking history. Materials and Methods: Blood samples were collected from 112 breast cancer female patients and 115 age-matched controls who underwent breast cancer screening with imaging and showed negative results (BI-RADS I or BI-RADS II). Genotyping was performed using the PCR-RFLP technique. Results: No statistically significant overall association was found between breast cancer risk and CYP1A1 M2 genotypes (p= 0.55; OR = 0.77; 95% CI= 0.32 - 1.83) nor with the M4 polymorphism (p= 0.95; OR= 0.95; 95% CI= 0.51 - 1.88). Analysis of subgroups defined by menopausal status or smoking history also revealed no association with these polymorphisms. Furthermore, the four identified haplotypes (AC; AA; GC and GA) were equally distributed among cases and controls, and haplotype analysis showed a strong linkage disequilibrium of both studied loci in either cases or controls (D'=1). Conclusions: Based on the study results, CYP1A1 M2 and M4 polymorphisms do not seem to play a major role in breast cancer risk among Jordanian females.

• Animal cells and systems
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• v.8 no.3
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• pp.205-212
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• 2004

The tumor suppressor protein p53 is stabilized by the herpes-virus-associated ubiquitin-specific protease (HAUSP), a deubiquitinating enzyme. We previously isolated and characterized a mouse orthologue of HAUSP, mHAUSP. mHAUSP cDNA consisted of 3,312 bp encodes 1,103 amino acids with a molecular weight of approximately 135 kDa containing highly conserved Cys, Asp (I), His, and Asn/Asp (II) domains. In this study, we carried out site-directed mutagenesis of 6 conserved amino acids (Cys224, Gln231, Asp296, His457, His465, and Asp482) in Cys box, QQD box, and His box. Interestingly, the conserved Gln 231 was not essential for the catalytic activity of mHAUSP. However, the other conserved amino acids were required for deubiquitinating activity of mHAUSP. We performed isopeptidase assay and confirmed that mHAUSP is able to remove ubiquitin from ubiquitinated substrates. In addition, we observed that mHAUSP induces apoptosis in HeLa cells.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2241-2244
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• 2017

The structure of concanavalin A (ConA) has been studied intensively owing to its specific interactions with carbohydrates and its heterometal ($Ca^{2+}$ and $Mn^{2+}$) coordination. Most structures from X-ray crystallography have shown ConA as a dimer or tetramer, because the complex formation requires specific crystallization conditions. Here, we reported the monomeric structure of ConA with a resolution of $1.6{\AA}$, which revealed that metal coordination could trigger sugar-binding ability. The calcium coordination residue, Asn14, changed the orientation of carbohydrate-binding residues and biophysical details, including structural information, providing valuable clues for the development and application of detection kits using ConA.

• Journal of the Korea Society of Computer and Information
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• v.9 no.3
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• pp.35-43
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• 2004

The management of network in TMN(Telecommunication Management Network) defines and manages the objects which are the operating system and communication equipments in network. The GDMO(Guideline Definition Managed Object) is used to describe those objects. GDMO is not directly used for managing network, but translated language into a language with object-oriented paradigm, then which is used. This paper presents design and implementation of the translator which automatically translates the specification of GDMO to the object-oriented language for generating MIB. And the system includes various graphic user interface to advance the development environment of GDMO.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.478-484
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• 1996

Recombinant human epidermal growth factor (rhEGF) was produced by E. coli BL21 harboring a plasmid pYHB101. The maximum production was 68.7 mg/l when the E. coli strain was cultured at 25$\circ$C for 48 hours in the modified MBL medium containing 10 g/l glucose with 1 mM IPTG induction at 2 hours after inoculation. The rhEGF was purified upto 267 folds by Amberlite XAD- 7 chromatography, ultrafiltration, and DEAE Sepharose fast flow ion exchange chromatography with an overall yield of 66.6%. The purified rhEGF was further separated into two fractions by HPLC. The N-terminal amino acid sequence of the second fraction was Asn-Ser-Asp-Ser-Glu-Cys-Pro-Leu-Ser-His. The effect of rhEGF on the DNA synthesis was examined using in vitro biological assay based on the incorporation of 5'-bromo-2'- deoxy-uridine (BrdU). The purified rhEGF shows no difference with natural human epidermal growth factor (nhEGF) in N-terminal amino acids residues and biological activity. From the results, we concluded that rhEGF produced from E. coli harboring the plasmid pYHB101 was apparently the same as nhEGF.

• Journal of Microbiology
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• v.40 no.1
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• pp.63-69
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• 2002

A total of twenty-five norfloxacin resistant Escherichia coli were isolated from Joongrang-chun stream, a branch of the Han River in Seoul, Korea from May to July in 2000 and their norfloxacin resistance mechanism was characterized for target site mutation, permeability, and efflux pump. Fourteen iso- lates contained the same three mutations, Ser83→Leu and Asp87→Asn in GyrA and Ser90→ lle in ParC. Six isolates had Ser83→Leu and Asp87→Tyr in GyrA and Ser87→lle in ParC while one isolate had Ser83→Leu and Va1103→Ala in GyrA and Ser80→lle in ParC. Two isolates had mutation(s) in GyrA without any mutation in ParC. Two isolates had Ser80→Arg in ParC instead of the commonly found Ser80→lle. Every norfloxacin resistant isolate had an efflux system but the correlation between the efflux activity and MIC was not observed. The amount of OmpF for norfloxacin permeability decreased in resistant isolates compared to the susceptible strains. When amplified polymorphic DNA (RAPD) and pulse field gel electrophoresis (PFGE) were performed, these isolates showed no similarity to each other or clinical isolates.

• Journal of Korean Society of Steel Construction
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• v.15 no.1
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• pp.33-40
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• 2003

There are two basic concepts about concerning the buckling analysis of a buried pipe. One concept considers the soil around the pipe asn elastic continuum mediaum. The other concept holds that the pipe is sup ported by an elastic spring, which replaces the effects of the surrounding soil (the Winkler model). Theise buckling analysis is based on plane analysis, without considering the corrugation effect and the length effect. This paper thus presents a parametric study using the Finite Element Method (FEM) for the Winker model and proposes a buckling strength formula after examining a 3D analysis considering the corrugation effect and the length effect, thatwhichhelp in estimating the critical buckling strength of such CSP