• YAKHAK HOEJI
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• v.36 no.2
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• pp.137-139
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• 1992

A new method for xenbucin, which is a antihypercholesteremic agent, is described. Friedel-Crafts reaction of biphenyl with ethyl ${\alpha}-chloro-{\alpha}-(methylthio)acetate(1)$ afforded ethyl 2-methylthio-2-(4-biphenylyl)acetate(2). Ethyl 2-(4-biphenylyl)butyrate(4) was obtained by ethylation of (2) with NaH and $C_2H_5I$, followed by desulfurization of the resultant ethyl 2-methylthio-2-(4-biphenylyl)butyrate(3) with zinc dust in acetic acid. Xenbucin was synthesized by hydrolysis of (4).

• Bulletin of the Korean Chemical Society
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• v.15 no.3
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• pp.245-249
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• 1994

NaMg[$Cr(C_2O_4)_3]{\cdot}10H_2O$ crystallizes in the trigonal space group P$\bar{3}$c1, with a=b= 16.969(3), c=12.521(3) ${\AA}$, ${\alpha}={\beta}=90^{\circ},\;{\gamma}=120^{\circ},\;{\rho}=1.734 \;gcm^{-3},\;{\mu}=6.46\;cm^{-1}$, Z=6. Intensities for 1062 unique reflections were measured on a four-circle diffractometer with Mo K${\alpha}$ radiation (${\lambda}=0.71069\;{\AA}$). The structure was solved by direct methods and refined to a final ${\omega}$R value of 0.084. X-ray crystal structure showed that magnesium ion appears to be occupied over two sites with the occupancy ratio of 2:1. The crystal possesses 10 water molecules instead of previously estimated 9 water molecules.

• Korean Journal of Materials Research
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• v.23 no.4
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• pp.227-232
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• 2013

Al-based alloys have recently attracted considerable interest as structural materials and light weight materials due to their excellent physical and mechanical properties. For the investigation of the potential of Al-based alloys, a surface porous $Al_{88}Cu_6Si_6$ eutectic alloy has been fabricated through a chemical leaching process. The formation and microstructure of the surface porous $Al_{88}Cu_6Si_6$ eutectic alloy have been investigated using X-ray diffraction and scanning electron microscopy. The $Al_{88}Cu_6Si_6$ eutectic alloy is composed of an ${\alpha}$-Al dendrite phase and a single eutectic phase of $Al_2Cu$ and ${\alpha}$-Al. We intended to remove only the ${\alpha}$-Al phase and then the $Al_2Cu$ phase would form a porous structure on the surface with open pores. Both acidic and alkaline aqueous chemical solutions were used with various concentrations to modify the influence on the microstructure and the overall chemical reaction was carried out for 24 hr. A homogeneous open porous structure on the surface was revealed via selective chemical leaching with a $H_2SO_4$ solution. Only the ${\alpha}$-Al phase was successfully leached while the morphology of the $Al_2Cu$ phase was maintained. The pore size was in a range of $1{\sim}5{\mu}m$ and the dealloying depth was nearly $3{\mu}m$. However, under an alkaline NaOH, aqueous solution, an inhomogeneous porous structure on the surface was formed with a 5 wt% NaOH solution and the morphology of the $Al_2Cu$ phase was not preserved. In addition, the sample that was leached by using a 7 wt% NaOH solution crumbled. Al extracted from the Al2Cu phase as ${\alpha}$-Al phase was dealloyed, and increasing concentration of NaOH strongly influenced the morphology of the $Al_2Cu$ phase and sample statement.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.4
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• pp.275-281
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• 2013

Astrocytes are reported to have critical functions in ischemic brain injury including protective effects against ischemia-induced neuronal dysfunction. Na-K ATPase maintains ionic gradients in astrocytes and is suggested as an indicator of ischemic injury in glial cells. Here, we examined the role of the Na-K ATPase in the pathologic process of ischemic injury of primary cultured astrocytes. Chemical ischemia was induced by sodium azide and glucose deprivation. Lactate dehydrogenase assays showed that the cytotoxic effect of chemical ischemia on astrocytes began to appear at 2 h of ischemia. The expression of Na-K ATPase ${\alpha}1$ subunit protein was increased at 2 h of chemical ischemia and was decreased at 6 h of ischemia, whereas the expression of ${\alpha}1$ subunit mRNA was not changed by chemical ischemia. Na-K ATPase activity was time-dependently decreased at 1, 3, and 6 h of chemical ischemia, whereas the enzyme activity was temporarily recovered to the control value at 2 h of chemical ischemia. Cytotoxicity at 2 h of chemical ischemia was significantly blocked by reoxygenation for 24 h following ischemia. Reoxygenation following chemical ischemia for 1 h significantly increased the activity of the Na-K ATPase, while reoxygenation following ischemia for 2 h slightly decreased the enzyme activity. These results suggest that the critical time for ischemia-induced cytotoxicity of astrocytes might be 2 h after the initiation of ischemic insult and that the increase in the expression and activity of the Na-K ATPase might play a protective role during ischemic injury of astrocytes.

• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.348-351
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• 1988

The production of extracellular $\alpha$-amylase by Bacillus thuringiensis 19 serotypes was examined by the hydrolysis test of starch. Thirteen serotypes produced the amylase. B. thuringiensis serovar thuringiensis alesti, kurstaki, sotto, kenya, israelensis, morrisoni, entomocidus, tolworthi, thompsoni, toumanoffi, pakistani, and indiana produced tee enzyme. The amylase produced by B. thuringiensis serovar israelensis showed highest activity around pH 6.7 to 7.2 and 55$^{\circ}C$ to $65^{\circ}C$. The high production medium of the amylase was composed of 1% bactopeptone, 0.3% beef-extract, 0.3% yeast ex-tract, 0.5% NaCl, 0.3% $K_2$HPO$_4$, 0.1% KH$_2$PO$_4$, 0.2% Soluble Starch, 0.012% CaCl$_2$.2$H_2O$$_2$, 0.005% MnCl$_2$, and 0.03% MgCl$_2$.7$H_2O$. The highest production of the enzyme was observed at 4 hours culture in the soluble starch (0.6 units/$m\ell$) or glucose (0.43 units/$m\ell$) substrate.

• Progress in Medical Physics
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• v.1 no.1
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• pp.97-107
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• 1990

A method of detecting charged particles in an allyl diglycol carbonate material (PN-3) which is available, amorphous, optically clear and thermoset plastic in which nuclear particle tracks could be revealed by etching in hot NaOH solutions, has been investigated. It has been applied to the study of alpha particle tracks over an energy range of 3.17～5.49 MeV which has been obtained after having passed through several sheets of polycarbonate. The dose equivalent rate of the alpha source was calculated and the spark chamber was used in order to measure the range of alpha particles after having passed through different number of absorbers. The etching characteristics and the detection response of PN-3 have been studied as a funcion of lengths of etched tracks against the parameters of energies and of the track etching rate(V$_{T}$). The investigation of the etching process for alpha particles in the PN-3 provided the most interesting results.s.

• Microbiology and Biotechnology Letters
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• v.23 no.4
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• pp.446-453
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• 1995

$\alpha $-Arabinofuranosidase was produced by E. coli HB101 haboring the recombinant plasmid pKMG11 which contained the arfI gene of Bacillus stearothermophilus. The maximum production of the enzyme was observed when E. coli HB101 cells were grown at 37$\circ$C for 20 hours in the medium containing 0.5% arabinose, 1.0% tryptone, 0.5% yeast extract, and 1% NaCl. The $\ALPHA $-arabinofuranosidase produced was purified to homogeneity using a combination of 20-50% ammonium sulfate precipitation, DEAE-Sepharose CL-6B ion exchange column chromatography and Sepharose 6B-100 gel filtration. The purified enzyme was most active at 55$\circ$C and pH 6.5. The K$_{m}$ and V$_{max}$ values of the enzyme on $\rho $-nitrophenyl-$\alpha $-arabinofuranoside was determined to be 2.99 mM and 0.43 $\mu $mole/min (319.74 $\mu $mole/min/mg), respectively. The pI value was 4.5. The molecular weight of the native protein was estimated to be 289 kDa. The SDS-polyacrylamide gel clectrophoresis analysis suggested that the functional protein was a trimer of the 108 kDa identical subunits. The N-terminal amino acid sequence of the a-arabinofuranosidase was identified as X-Ser-Thr-Ala-Pro-Arg( \ulcorner )-Ala-Thr-Met-Val-Ile-Asp-X-Ala-Phe.

• YAKHAK HOEJI
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• v.32 no.4
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• pp.258-273
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• 1988

In this study attempts were made to observe the effects of guanabenz on renal function in dog, which manifests the antihypertensive action by inhibition of sympathetic tone through stimulating the presynaptic adrenoceptor (${\alpha}_2-adrenoceptor$). Guanabenz, when injected at a dose of $30.0{\mu}g/kg$, or infused at a dose of $3.0{\mu}g/kg/min$ intravenously, produced diuretic action with increased amounts of $Na^+\;and\;K^+$ in urine, and with decreased reabsorption rates of $Na^+\;and\;K^+$ in renal tubules. It was also observed that the rates of osmolar and free water clearances were increased, but the glomerular filtration rate and renal plasma flow were not changed. Guanabenz injected at a dose of $3.0{\mu}g/kg$ into a carotid artery or infused intravenously at a dose of $3.0{\mu}g/kg/min$ in a state of water diuresis elicited the diuretic action of the similar aspect as a case of guanabenz given intravenously. The diuretic action produced by guanabenz was completly blocked by pretreatment of i.v. prazosin, ${\alpha}_1-adrenoblocking$ agent, or of i.v. yohimbine, ${\alpha}_2-adrenergic$ blocking agent. Prazosin, when given into a renal artery, inhibited the diuretic action by i.v. guanabenz in only injected kidney, whereas in case of yohimbine the action was inhibited in both kidney. Guanabenz infused at a dose of $1.0{\mu}g/kg/min$ into a renal artery exhibited no significant changes of renal function in both kidney. In denervation experiments, guanabenz given intravenously produced typical diuretic action in innervated kidney, whereas in denervated kidney, it did not affect the action at initial period but exhibited the action with increase of only free water clearance at later period. These results suggest that guanabenz produced diuretic action in dog by inhibition of electrolyte reabsorption rates in renal tabules, mainly proximal tubule and of ADH release, which is mediated by stimulating of central sympathetic ${\alpha}_2-receptor$.

• Journal of the Korean Ceramic Society
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• v.35 no.2
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• pp.185-195
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• 1998

This experiment carried out in order to investigate the effect of the chemical activators for acceleration of hydration the system of Fly ash-Cao The paste was consisted of 80wt% Fly ash and 20wt% CaO with 1. 3. 5wt% of 4 activators(N{{{{ alpha _2 }}S{{{{ OMICRON _4 }}, CaC{{{{ {l }_{2 } }}, NaOH, Ca(N{{{{ OMICRON _3 {)}_{2 } }} and W/S ratio of 0.42 After curing for 1, 3, 7, 14, 28 days the paste hydration was characterized by the measurement of compressive strength XRD analysis SEM observation the combined water and the reaction amount of Ca(OH)2 determination. As a result of this ex-periment all of the system which involved Na2SO4 or NaOH had a god compressive strength. In the case of 7 days curing a system which added CaCl2 showed the highest compressive strength among all especially NaOH system showed a high increase in strength as a dosage of it increased. Hydration products were different according to activatores added. Only C-S-H was observed in NaOH system. As the reaction amount of Ca(OH)2 and combined water were increased the compressive strength increased. There were few differences in the comparision of strength between ignited loss 3.1% and loss 9.3% of fly ash.

• Korean Journal of Clinical Pharmacy
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• v.28 no.4
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• pp.333-341
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• 2018

Objective: Tumor necrosis factor-alpha (TNF-alpha) inhibitors are used as a treatment in various immune-mediated inflammatory diseases (IMIDs). Tuberculosis (TB) risk is reported in several meta-analyses in patients treated with TNF-alpha inhibitors. The purpose of this study is to collect, review, and evaluate the TB risk in TNF-alpha inhibitors according to IMIDs indications and between soluble-receptor TNF-alpha inhibitor and monoclonal-antibody TNF-alpha inhibitors. Methods: A systematic literature search on systematic reviews and meta-analyses was performed in PubMed, MEDLINE, Cochrane library, and EMBASE. We identified meta-analyses that evaluated TB infection risk of TNF-alpha inhibitors in IMIDs patients. Results: Thirteen meta-analyses including 41 study results were included in this umbrella review. IMIDs patients treated with TNF-alpha inhibitors had an increased risk of TB than control group (placebo with or without standard therapy patients) (relative risk ratio (RR) 2.057, 95% confidence interval (CI) 1.697 to 2.495). Among them, RA patients with TNF-alpha inhibitors had a higher risk of TB than control group (RR 1.847, 95% CI 1.385 to 2.464), and non-RA patients with TNF-alpha inhibitors had an increased risk of TB (RR 2.236, 95% CI 1.284 to 3.894). In subgroup analysis on TB risk between soluble-receptor TNF-alpha inhibitor and monoclonal-antibody TNF-alpha inhibitors in RA patients, the analysis indicated that monoclonal-antibody TNF-alpha inhibitors had higher risk of TB than soluble-receptor TNF-alpha inhibitor (RR 2.880, 95% CI 1.730 to 4.792). Conclusion: This umbrella review confirms that the risk of TB is significantly increased in TNF-alpha inhibitor treated patients compared to control group.