• Childhood Kidney Diseases
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• v.13 no.1
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• pp.56-62
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• 2009

Purpose : The aim of this study was to evaluate the clinical usefulness of measurement of ${\beta}_2$ microglobulin (${\beta}_2$ MG), N-acetyl-$\beta$-D-glucosaminidase (NAG) of spot urine samples as indices of renal tubular damage and microalbumin of spot urine samples as a parameter of glomerular damage in children with vesicoureteral reflux (VUR) or renal defects. Methods : We studied 91 children with previous UTI. The children were classified as 62 children without VUR and renal defects (group I), 10 children with VUR, without renal defects (group II), and 19 children with VUR and renal defects (group III). Patients having VUR were separated according to the degree of VUR (mild VUR: VUR grade I-III, severe VUR: VUR grade IV-V). Urinary excretion of ${\beta}_$ microglobulin (${\beta}_2$ MG), microalbumin, N-acetyl-$\beta$-D-glucosaminidase (NAG), creatinine were measured in samples of morning urine specimens. Children with VUR or renal defects detected by voiding cystourethrography (VCUG) and DMSA renal scan were investigated. Results : Microalbumin/Cr ratio of spot urine was significantly increased in group III compared group I ($42.3{\pm}27.2\;mg/gCr$ vs $25.2{\pm}10.9\;mg/gCr$, P<0.05). NAG/Cr ratio of spot urine was significantly increased in group II compared group I ($3.70{\pm}23.4\;mg/gCr$ vs $18.7{\pm}12.7\;mg/gCr$, P<0.05). There was no statistically significant difference of ${\beta}_2$ MG/Cr ratio among three groups. Conclusion : Urinary microalbumin excretion of morning urine sample may be a simple and reliable clinical indicators for early identification of renal damage in children with VUR and renal defects. Urinary microalbumin excretion may be useful marker to predict the the severity of VUR.

• Progress in Medical Physics
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• v.14 no.4
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• pp.259-267
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• 2003

In vivo $^1$H magnetic resonance spectroscopy (MRS) at 4.7 T was applied to investigate the cerebral metabolite changes of mice brain before and after experimental brain trauma. In vivo $^1$H MR spectra were acquired from a voxel covering right parietal cortex in normal brain, used as control subjects. After experimental brain trauma using the fluid percussion injury (FPI) method, $^1$H MR spectra were acquired from the same lesion three days after trauma. Metabolite ratios of the injured lesion were compared to those of controls. After trauma, N-acetylaspartate (NAA)/creatine (Cr) ratio, as a neuronal marker was decreased significantly versus controls, indicating neuronal loss. The ratio of NAA/Cr in traumatic brain contusion was 0.90$\pm$0.11, while that in normal control subjects was 1.13$\pm$0.12 (P=0.001). Choline (Cho)/Cr ratio had a tendency to rise in experimental brain contusion (P=0.02). Cho/Cr ratio after trauma was 0.91$\pm$0.17 while that before traumas was 0.76$\pm$0.15. Cho/Cr ratio was increased and this might indicate a inflammatory activity. However, no significant difference of [(glutamate＋glutamine) (Glx)]/Cr was established between experimental traumatic brain injury models and normal controls. Lactate (Lac)/Cr ratio was appeared as a sign of shifted posttraumatic energy metabolism and increased versus controls. These findings strongly suggest that in vivo $^1$H MRS may be a useful modality for clinical evaluation of traumatic contusion and could aid in better understanding the neuropathologic process of traumatic contusion induced by FPI. In the present study, in vivo $^1$H MRS was proved to be a useful non-invasive method for in vivo diagnosis and monitoring of posttraumatic metabolism in models of brain contusion.

• Macromolecular Research
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• v.11 no.6
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• pp.506-510
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• 2003

A Zn ion-coated nanosilica filler has been developed and tested, in chlorosulfonated polyethylene (CSPE) and polychloroprene (CR), as a vulcanizing activator, cum was reinforcing filler. In this study, ZnO was replaced by the Zn ion-coated nanosilica filler with an aim of studying the dual role of this nanofiller in CSPE and CR. In the case of CSPE vulcanizates, the presence of MgO deteriorated the state and rate of cure when the Zn ion-coated nanosilica filler was used, but in the case of CR it improved the state of cure and enhanced the modulus and tensile strength. The Zn ion-coated filler proved to be a better reinforcing-cum-curing agent than was externally added ZnO and NA-22 also proved to be a better curative in the presence of the Zn ion-coated nanosilica filler for both CSPE and CR.

• Elastomers and Composites
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• v.22 no.4
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• pp.314-323
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• 1987

A blend ratio of rubber vulcanzates comprising NBR, CR, EPDM, NR, BR, and SBR alone or blended is determind through a P.G.C. It is found that a characteristic peak of elastomer is proportional to the content of each elastomer when they are pyrolysed. It is also classified to the different AN content in NBR vulcanizates, identification of sulfur-modified and non-sulfur bearing CR polymers, and the content of ethylene, propylene monomer and the third monomer in EPDM vulcanizetes.

• Bulletin of the Korean Mathematical Society
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• v.48 no.3
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• pp.585-600
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• 2011

In this paper we derive an integral formula on an (n + 3)-dimensional, compact, minimal contact three CR-submanifold M of (p-1) contact three CR-dimension immersed in a unit (4m+3)-sphere $S^{4m+3}$. Using this integral formula, we give a sufficient condition concerning the scalar curvature of M in order that such a submanifold M is to be a generalized Clifford torus.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.10
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• pp.532-535
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• 2001

The sputtering condition of Cr thin film was established in order to get Cr gate electrode having a vertical wall structure for Mo-tip FEA. In case of Mo-tip FEA which had a vertically-etched Cr gate electrode, the field enhancement factor, was relatively increased and so the field emission performance in terms of turn-on voltage, emission current and trans-conductance could be improved when compared with the devices having a tapered gate wall.

• International Journal of Railway
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• v.3 no.1
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• pp.19-27
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• 2010

In the present study, the electrical sliding wear and corrosion resistance of pure copper (Cu) and six age-hardened copper alloys (CuCr, CuZr, CuCrZr, CuNiSiCr, CuBe and CuBeNi) were investigated by a pin-on-disc tribometer and electrochemical measurement. Various copper-based alloys in the form of cylindrical pin were forced to slide against a counterface stainless steel disc in air under unlubricated condition at a sliding velocity of 31 km/h under normal load up to 20 N with and without electric current. The worn surface of and wear debris from the specimens were studied by scanning electron microscopy. Both mechanical wear and electrical arc erosion were the wear mechanisms for the alloys worn at 50 A. Owing to its good electrical conductivity, high wear and corrosion resistance, CuCrZr is a promising candidate as the overhead catenary material for electric traction systems.

• Membrane and Water Treatment
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• v.12 no.1
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• pp.11-21
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• 2021

A novel activated carbon produced from cherry laurel (Laurocerasus officinalisRoem.) seeds (CLSAC) by chemical activation with ZnCl2 was used as an adsorbent to remove Cr(VI) ions from aqueous solutions. CLSAC was characterized by several techniques and the adsorption experiments were performed in a batch model adsorption technique. The effects of various experimental parameters were investigated as a function of solution pH, contact time, initial Cr(VI) concentration, CLSAC concentration, and temperature. The monolayer adsorption capacity of CLSAC was found to be 41.67 mg g-1 for 5.0 g L-1 of CLSAC concentration and, it was concluded that CLSAC can be used as an effective adsorbent for removal of Cr(VI) from waters and wastewaters.

• Journal of the Korean Society of Radiology
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• v.82 no.3
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• pp.654-669
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• 2021

Purpose To evaluate the accuracy of MRI in predicting the pathological complete response (pCR) and the residual tumor size of breast cancer after neoadjucant chemotherapy (NAC), and to determine the factors affecting the accuarcy. Materials and Methods Eighty-eight breast cancer patients who underwent surgery after NAC at our center between 2010 and 2017 were included in this study. pCR was defined as the absence of invasive cancer on pathological evaluation. The maximum diameter of the residual tumor on post-NAC MRI was compared with the tumor size of the surgical specimen measured pathologically. Statistical analysis was performed to elucidate the factors affecting pCR and the residual tumor size-discrepancy between the MRI and the pathological measurements. Results The pCR rate was 10%. The diagnostic accuracy of MRI and the area under the curve for predicting pCR were 90.91% and 0.8017, respectively. The residual tumor sizes obtained using MRI and pathological measurements showed a strong correlation (r = 0.9, p < 0.001), especially in patients with a single mass lesion (p = 0.047). The size discrepancy between MRI and the pathological measurements was significantly greater in patients with the luminal type (p = 0.023) and multifocal tumors/non-mass enhancement on pre-NAC MRI (p = 0.047). Conclusion MRI is an accurate tool for evaluating pCR and residual tumor size in breast cancer patients who receive NAC. Tumor subtype and initial MRI features affect the accuracy of MRI.

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.234-236
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• 2003