Effect of low concentrations of hydrogen peroxide on the contractile responses of rat detrusor smooth muscle strips

Han, J.H.,Lee, M.Y.,Lee, S.Y.,Chang, I.H.,Kim, H.J.,Kim, W.,Myung, S.C. North-Holland ; Elsevier Science Ltd 2010 european journal of pharmacology Vol.638 No.1

This study was designed to determine how the contractility of rat detrusor smooth muscle strips changes in the presence of low concentrations of hydrogen peroxide (H<SUB>2</SUB><SUB>2</SUB>. The strips were dissected from the base of Sprague-Dawley rat bladders and their contractile responses to a cumulative increase in H<SUB>2</SUB><SUB>2</SUB>concentration (3x10<SUP>-6</SUP>3x10<SUP>-2</SUP>%) were measured. How the duration of exposure to the fixed concentration of 3x10<SUP>-4</SUP>% H<SUB>2</SUB><SUB>2</SUB>affected contractility was also examined. Moreover, the effect of 3x10<SUP>-4</SUP>% H<SUB>2</SUB><SUB>2</SUB>pretreatment on the response to cumulative increases in the concentrations of phenylephrine or acetylcholine (10<SUP>-8</SUP>10<SUP>-4</SUP>) was assessed. To elucidate the mechanism by which H<SUB>2</SUB><SUB>2</SUB>induced contraction, we examined the effect of pretreatment with 10nM Y-27632, 10μM indomethacin, 10μM SQ29548, 10μM verapamil, 10μM vitamin E, or 1μM Bay-K 8644 on the contractile responses generated by cumulatively increasing the concentration of H<SUB>2</SUB><SUB>2</SUB> H<SUB>2</SUB><SUB>2</SUB>induced contractile responses in Ca<SUP>2+</SUP>free physiological solution were also examined. Low concentrations of H<SUB>2</SUB><SUB>2</SUB>increased the contractile responses of the strips in a dose-dependent manner but increasing treatment duration decreased these responses. H<SUB>2</SUB><SUB>2</SUB>pretreatment significantly augmented the contraction induced by phenylephrine (P<0.05) but had no effect on the response to acetylcholine. Pretreatment with Y-27632, indomethacin, vitamin E, verapamil, and Bay-K 8644 significantly inhibited the H<SUB>2</SUB><SUB>2</SUB>induced contraction (P<0.05). SQ 29548-pretreatment had no effect. H<SUB>2</SUB><SUB>2</SUB>could not increase the contractile responses in Ca<SUP>2+</SUP>free physiological solution. Thus, low concentrations of H<SUB>2</SUB><SUB>2</SUB>may directly affect detrusor smooth muscles and thereby induce detrusor overactivity.

Effects of calcium doping on the superconducting properties of top-seeded melt growth processed Y_1.5Ba_2-xCa_xCu₃O_y superconductors

Park, S.D.,Kim, H.J.,Park, B.J.,Han, Y.H.,Jun, B.H.,Lee, J.S.,Kim, C.J. North-Holland 2011 Physica. C, Superconductivity Vol.471 No.21

The effect of calcium doping on the superconducting properties of top seeded melt growth (TSMG) processed Y<SUB>1.5</SUB>Ba<SUB>2-x</SUB>Ca<SUB>x</SUB>Cu<SUB>3</SUB>O<SUB>y</SUB> superconductors was studied in terms of calcium content (X<SUB>ca</SUB>). YBa<SUB>2-x</SUB>Ca<SUB>x</SUB>Cu<SUB>3</SUB>O<SUB>7-δ</SUB> (X<SUB>ca</SUB>=0, 0.005, 0.01, 0.02, 0.04, 0.1, 0.3) powders were synthesized by the powder calcination method. YBa<SUB>2-x</SUB>Ca<SUB>x</SUB>Cu<SUB>3</SUB>O<SUB>7-δ</SUB> powders were mixed with 0.25mole Y<SUB>2</SUB>O<SUB>3</SUB> powder and 1wt.% CeO<SUB>2</SUB> as Y<SUB>2</SUB>BaCuO<SUB>5</SUB> (Y211) refiner, and finally made into Y<SUB>1</SUB>.<SUB>5</SUB>Ba<SUB>2-x</SUB>Ca<SUB>x</SUB>Cu<SUB>3</SUB>O<SUB>y</SUB> (Y1.5)+1wt.% CeO<SUB>2</SUB> composition. The single Y123 growth on the top surface was observed up to X<SUB>ca</SUB>=0.1, while the multiple Y123 growth was observed at X<SUB>ca</SUB>≥0.1. The superconducting transition temperature (T<SUB>c</SUB>) and critical current density (J<SUB>c</SUB>) of TSMG processed Y1.5 samples were inversely proportional to X<SUB>ca</SUB>. The Y211 size increased with increasing X<SUB>ca</SUB> due to the enhancement of Y211 coarsening by calcium doping. No Y211 refining effect by CeO<SUB>2</SUB> was observed in the calcium doped samples. The T<SUB>c</SUB> and J<SUB>c</SUB> decrease by calcium doping are likely to be due to the calcium incorporation with the Y123 lattice and formation of coarse Y211 particles.

Effects of Y₂O₃ additions on the oxygen diffusion in top-seeded melt growth processed YBa₂Cu₃O_7-y superconductors

Jun, B.H.,Jung, S.A.,Park, S.D.,Park, B.J.,Han, Y.H.,Kim, C.J. North-Holland 2011 Physica. C, Superconductivity Vol.471 No.21

To understand the effect of Y<SUB>2</SUB>BaCuO<SUB>5</SUB> (Y211)/YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7-y</SUB> (Y123) interfaces on the oxygen diffusion in single grain YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7-y</SUB> superconductors, single grain Y123 superconductors with 0.05 and 0.3moles of Y<SUB>2</SUB>O<SUB>3</SUB> additions were fabricated by a top-seeded melt growth (TSMG) process. Y123 compacts with Y<SUB>2</SUB>O<SUB>3</SUB> additions were subjected to melt growth heating cycles with a cooling rate of 1<SUP>o</SUP>C/h through a peritectic temperature (1015<SUP>o</SUP>C) and then annealed at 450<SUP>o</SUP>C for 200h in flowing oxygen. The superconducting temperature (T<SUB>c</SUB>) and critical current density (J<SUB>c</SUB>) were estimated for the three different regions (top surface (s), intermediate (i) and center (c)) of samples. The amount of Y211/Y123 interface area in single grain Y123 superconductors was successfully controlled by Y<SUB>2</SUB>O<SUB>3</SUB> additions. The T<SUB>c</SUB> values of s regions were higher than those of i and c regions, which indicates the presence of more oxygen at the sample surfaces. In addition, the T<SUB>c</SUB> values of i and c regions of the Y123 sample with 0.3mole Y<SUB>2</SUB>O<SUB>3</SUB> addition were higher than those of the same regions of the Y123 sample with 0.05mole Y<SUB>2</SUB>O<SUB>3</SUB> addition due to the promoted oxygen diffusion through Y211/Y123 interfaces and other related defects. In spite of the promoted oxygen diffusion by Y<SUB>2</SUB>O<SUB>3</SUB> addition, the large T<SUB>c</SUB> difference among the regions still existed, which suggests sluggish oxygen diffusion into single Y123 grains.

Particle distribution in melt-processed Y_1.5 Ba₂Cu₃O_x superconductors with BaCeO₃ addition

Youn, J.S.,No, K.,Kim, Y.H.,Mahmood, A.,Jun, B.H.,Han, Y.H.,Sung, T.H.,Kim, C.J. North-Holland 2009 Physica. C, Superconductivity Vol.469 No.15

To understand the effect of BaCeO<SUB>3</SUB> on a Y<SUB>2</SUB>BaCuO<SUB>5</SUB> (Y211) distribution, Y<SUB>1.5</SUB>Ba<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>x</SUB> (Y1.5) superconductors with/without 1wt.% BaCeO<SUB>3</SUB> additions were prepared by a top-seeded melt-textured growth (TSMG) process. Two different BaCeO<SUB>3</SUB> powders (as-synthesized (coarse powder) and an attrition-milled (fine powder)) were used and the size effect was compared with that obtained from a Y1.5 sample with no addition. A refinement of the Y211 particles was achieved for both the as-synthesized and attrition-milled BaCeO<SUB>3</SUB> additions. The distribution of the Y211 particles was most uniform in the Y1.5 sample prepared with the attrition-milled BaCeO<SUB>3</SUB> powder due to the reduced size of the Y211-free regions by the fine size BaCeO<SUB>3</SUB> addition. The highest J<SUB>c</SUB> was achieved in the Y1.5 sample prepared with the attrition-milled BaCeO<SUB>3</SUB> powder. The J<SUB>c</SUB> result agreed well with the microstructure variations by the addition of BaCeO<SUB>3</SUB> powders.

Effective pore control and critical current density in liquid infiltration growth processed Y-123 superconductors with Ag addition

Mahmood, A,Jun, B-H,Han, Y H,Kim, C-J IOP Publishing Ltd 2010 Superconductor science & technology Vol.23 No.6

<P>The effect of a sintered density (open porosity) of Y<SUB>2</SUB>BaCuO<SUB>5</SUB> (Y211) pre-forms on the final porosity and Y211 size within Y Ba<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7 − <I>y</I></SUB> (Y-123) products was systematically studied in liquid infiltration growth (LIG) processed Y-123 bulk superconductors with Ag addition. To prepare Y211 pre-forms of various densities, Y211 powder compacts were sintered in air at various temperatures of 900–1200 °C. The single-grain Y-123 bulk superconductors were fabricated by the LIG process with top seeding. It was found that the porosity of the final Y-123 product was fairly dependent on the Y211 pre-form density. When a Y211 pellet of a high density was used as a pre-form for the LIG process, the porosity of the final Y-123 product was greatly reduced. In addition to the reduced porosity, the enhanced Y211 refinement was achieved for the Y-123 product prepared using the dense Y211 pre-form, resulting in the improved critical current density (<I>J</I><SUB>c</SUB>). The Ag addition was also helpful in eliminating the spherical pores through pore filling with a silver melt. The pore elimination and Y211 refinement mechanism in the LIG-processed Y-123 bulks were explained in terms of the liquid capillary movement and Ag melt and particle coarsening at the (Y 211 + melt) state.</P>

Urinary concentration of transforming growth factor-&bgr;-inducible gene-h3(&bgr;ig-h3) in patients with Type 2 diabetes mellitus

Cha, D. R.,Kim, I. S.,Kang, Y. S.,Han, S. Y.,Han, K. H.,Shin, C.,Ji, Y. H.,Kim, N. H. Blackwell Science Ltd 2005 Diabetic medicine Vol.22 No.1

<P>Abstract</P><P>Aims </P><P>The expression of TGF&bgr;-inducible gene h3(&bgr;ig-h3) has been used to assess the biological activity of TGF&bgr; in the kidney. In this study, we investigated whether the urinary concentration of &bgr;ig-h3 is associated with diabetic nephropathy in patients with Type 2 diabetes mellitus. We also evaluated the relationship between the urinary concentration of &bgr;ig-3 and proteinuria and microalbuminuria (AER) in a normal healthy population and in Type 2 diabetes patients.</P><P>Methods </P><P>Four hundred and seventy-nine Type 2 diabetic patients without non-diabetic kidney diseases and 528 healthy control subjects were enrolled. The study subjects were divided into five groups: a non-diabetic healthy control group with normal ACR (<I>n</I> = 443), a non-diabetic healthy control group with microalbuminuria (<I>n</I> = 85), a normoalbuminuric diabetic group (<I>n</I> = 198), a microalbuminuric diabetic group (<I>n</I> = 155) and an overt proteinuria group (<I>n</I> = 126). Urinary levels of &bgr;ig-h3 were measured by enzyme-linked immunosorbent assay.</P><P>Results </P><P>(i) Urinary excretion of &bgr;ig-h3 was significantly higher in the diabetic groups than in the controls, even in the normoalbuminuric stage (25.02 ± 8.84 vs. 18.67 ± 6.56, <I>P</I> = 0.03). In diabetic patients, urinary &bgr;ig-h3 levels increased significantly as diabetic nephropathy advanced (25.02 ± 8.84 vs. 34.06 ± 24.55 vs. 169.63 ± 57.33, <I>P</I> < 0.001). (ii) Proteinuria was found to be significantly correlated with urinary &bgr;ig-h3 (healthy control; <I>r</I> = 0.137, <I>P</I> = 0.019, diabetic patients; <I>r</I> = 0.604, <I>P</I> < 0.001). ACR was also found to be significantly related with urinary &bgr;ig-h3 in diabetic patients (<I>r =</I> 0.383, <I>P</I> = 0.006). (iii) In diabetic patients, urinary &bgr;ig-h3 was significantly related with systolic and diastolic blood pressure (systolic blood pressure: <I>r</I> = 0.436, <I>P</I> = 0.024; diastolic blood pressure, <I>r</I> = 0.365, <I>P</I> = 0.042), total cholesterol and HbA<SUB>1c</SUB> (cholesterol: <I>r</I> = 0.169, <I>P</I> = 0.03, HbA<SUB>1c</SUB>; <I>r</I> = 0.387, <I>P</I> = 0.044). Logistic regression analyses showed that urinary &bgr;ig-h3 was associated with a significant increase in the risk of microalbuminuria and proteinuria in diabetic patients.</P><P>Conclusions </P><P>Longitudinal monitoring of urinary &bgr;ig-h3 may improve the likelihood of detecting diabetic nephropathy at an earlier stage and &bgr;ig-h3 could be a sensitive marker of diabetic kidney disease progression.</P>

Effects of $BaCO_3$ purity on the superconducting properties of top seeded melt growth processed $Y_{1+x}Ba_2Cu_3O_y$ superconductors

Choi, J.S.,Park, S.D.,Jun, B.H.,Han, Y.H.,Sung, T.H.,Choo, K.N.,Kim, C.J. The Korean Society of Superconductivity and Cryoge 2009 한국초전도저온공학회논문지 Vol.11 No.2

Effects of $BaCO_3$ purity on the superconducting properties of top seeded melt growth (TSMG) processed $Y_{1+x}Ba_2Cu_3O_{7-y}$ (Y1+x, x=0.1 and 0.2) superconductors were investigated. $YBa_2Cu_3O_{7-y}$ (Y123) powder prepared using $BaCO_3$ with 99.75% purity and commercially available Y123 powder of 99.9% were used for the fabrication of single Y123 grain superconductors. $T_c$ values of the Y1+x samples prepared using low purity Y123 powder were slightly lower than those of the samples prepared using a high purity powder. In addition to the lower $T_c$, an anomalous peak effect in the intermediate magnetic fields was observed in Y1+x samples prepared using the low purity $BaCO_3$ powder. The slight decrease in $T_c$ and the anomalous peak effect are ascribed to the possible incorporation of a Y123 phase with impurity elements such as strontium and calcium included in the $BaCO_3$powder of 99.7%. The result suggests that the low purity $BaCO_3$ powder of a low price can be used as a raw power for the fabrication of single grain YBCO bulk superconductors.

The mechanism of hydrogen embrittlement in intercritically annealed medium Mn TRIP steel

Han, J.,Nam, J.H.,Lee, Y.K. Elsevier Science 2016 Acta materialia Vol.113 No.-

<P>The objective of this study was to investigate the mechanisms of hydrogen embrittlement (HE) in intercritically annealed medium Mn steel. For this purpose, both hot-rolled and cold-rolled Fe-7Mn-0.1C-0.5Si (wt.%) steels were annealed at 640 degrees C for 30 min. The annealed specimens had a dual-phase microstructure of retained austenite (gamma R) and ferrite (alpha) with different morphologies; a lath shape for the hot-rolled and annealed (HRA) specimen and a globular shape for the cold-rolled and annealed (CRA) specimen. Although the difference in microstructural morphology did not influence the H permeation, it significantly affected the HE behavior. The H-charged HRA (HRA(H)) specimen was fractured by inter granular cracking occurring along the boundaries of prior gamma grains by the H-enhanced decohesion (HEDE) mechanism. The intergranular cracking leaved both flat and rugged facets, which appeared at the prior gamma grain boundaries without and with gamma R, respectively. The H-charged CRA (CRA(H)) specimen was fractured to leave both dimples filled with grains and empty dimples at the fractured surface. The dimples filled with grains were generated by intergranular cracking occurring along the boundaries of gamma R grains by the HEDE mechanism. The empty dimples were made by intragranular cracking occurring inside the alpha grains by the H-enhanced local plasticity (HELP) mechanism. The CRA(H) specimen exhibited a smaller elongation loss than the HRA(H) specimen because cracks were propagated by frequently changing their direction along the boundaries of nano-sized gamma R grains or into alpha grains. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.</P>

An assessment of axial pre-compression for the KSTAR central solenoid

Ahn, H.J.,Kim, H.T.,Kim, Y.O.,Chu, Y.,Park, H.K.,Park, K.R.,Oh, Y.K.,Kim, Y.S.,Han, D.W.,Kim, Y.H. Elsevier 2017 Fusion engineering and design Vol.124 No.-

<P><B>Abstract</B></P> <P>The central solenoid (CS) of the KSTAR consists of four pairs of superconducting coils compressed axially by preloading structures. The axial pre-compression is needed to suppress the maximum attractive or repulsive force of the coils based on reference operation scenarios. All CS coils were assembled with eight sets of preloading and supporting structures under precise dimensional control. Only shells of preloading structures were heated to make 6mm gap between the preloading structure and coil assembly. The gap was, then, filled up by wedge movement so that axial pre-compression be applied after thermal contraction of shells. However measured pre-compression is about 55% of the design value. A detailed investigation has been carried out to find reasons for the preloading reduction by comparing strain measurement and structural analysis results. The minimum residual compression is estimated as 6.5MN. It is expected to have no serious problem during large plasma current H-mode discharge with consideration of the anti-slip design. A structural analysis model of KSTAR CS magnet has been developed based on the measured strains during operations and will give a guide line for future high performance and long pulse operations of KSTAR.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A detailed investigation has been carried out to find reasons for the preloading reduction for KSTAR CS by comparing strain measurement and structural analysis results. </LI> <LI> A structural analysis model of KSTAR CS magnet has been developed based on the measured strains during operations. </LI> <LI> It is expected to have no serious problem during large plasma current H-mode discharge in future with consideration of the anti-slip design of each component. </LI> </UL> </P>

볏짚의 사료가치 증진을 위한 적정 알카린 H2O2 처리 수준에 관한 연구

문양수(Y . S . Moon),하종규(J . K . Ha),고종열(J . Y . Ko),최연호(Y . H . Choy),조경훈(G . H . Cho),최윤재(Y . J . Choi),한인규(I . K . Han) 한국축산학회 1990 한국축산학회지 Vol.32 No.10

This study was carried out to determine the adequate levels of alkaline hydrogen peroxide treatment for the improvement of nutritive value of rice straw. In vitro digestibility and chemical analysis after several treatments were measured. Treatment variables were soaking time(12, 24, 48 and 96 hrs), temperature(5, 25, 50 and 75℃) of alkaline H₂0₂ solution, H₂0₂ concentration (0.5, 1, 2, 3 and 4%) and substrate /solution ratio (1, 2, 3, 4 and 5g/ml). The results obtained were summarized as follows. 1. The DM digestibilities or rice straw treated with H₂O₂ for 24 and 48 hours were higher than those of the others(p$lt;0.05). There was no differ ences when the rice straw was treated for 12, 72 or 96 hours. Cell wall contents were not affected by the time of treatment. 2. The DM digestibilities were higher at pH 11.5 or above(p$lt;0.05) and was decreased as pH declined. When rice straw was treated with H₂O₂ at pH 11.5 or higher, NDF, ADF and cellulose contents were increased. However, lignin content and DM recovery percentages were decreased. 3. The DM digestibilities were not influenced by the ratio of straw versus liquid. The contents of NDF and cellulose were not affected up to the ratio of 4g rice straw/50m1, but were decreased at 5g rice straw/50m1. Lignin content and DM recovery percentages, however, were increased at 5g rice straw /50m1. 4. The DM digestibilities were not different among treatments at 5, 25 and 50℃. However, the rice straw treated at 75℃ showed lowest digestibility of all treatment (p$lt;0.05). The content of NDF, ADF and cellulose was increased by increasing temperature. However, lignin content and DM recovery percentages were decreased by increasing temperature. 5. The AHP treated rice straw had higher content of ADF and cellulose, and lower content of hemicellulose and lignin as the concentration of H₂O₂, increased. But hemicellulose, lignin and DM recovery percentages were decreased. The NDF content was not different among five different concentrations of H₂0₂ solution. In conculsion, based upon the results of present experiments the most desirable method is to soak rice straw in 1% alkaline H₂0₂ solution at pH 11.5, at room temperatrve (25℃), for 24∼48 hours and at the ratio of 4g rice straw /50m1 solmtion.