• Journal of Radiation Protection and Research
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• v.21 no.1
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• pp.9-16
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• 1996

For the determination of radiostrontium, $^{89}Sr\;and\;^{90}Sr$ in environmental soil sample, a solvent extraction method for the separation of Ca and Sr from matrix using crown ether was investigated. In comparison with the existing fuming nitric acid method, the extraction method showed high chemical yield of strontium and provided simple and rapid analytical steps. The new analytical method applied to the determination of radiostrontium in some soil sample around a nuclear power station to show that the analytical procedure is readily applicable to the practical radioactivity monitoring.

• The Journal of the Petrological Society of Korea
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• v.2 no.2
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• pp.130-138
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• 1993

Kyeonggi Gneiss complex forming Korean Precambrian basement is mainly composed of high-grade metasedimentary rocks, which are generally difficult to determine their absolute ages. We examined the feasibility of successive absolute age determination method for the marbles from this basement. We used hydrochloric acid for the selective dissolution of carbonate minerals from the marbles. Trace element analysis shows that most of Zr and Rb are concentrated in the residues. U in the residue is more abundant than that in HC1-dissolved parts. Pb, Sr, Sm, and Nd are somewhat evenly distributed between HC1-dissolved parts and the residues. }Th shows rather complex behavior. Sr isotopic compositions of the HC1-dissolved parts reveal mixing with Sr from non-carbonate minerals having much higher $^{87}Sr/^{86}Sr$ ratios. We suggest that the most reliable method in the age determination for the marbles of this area is measuring Pb isotopic ratios of the pieces of pure marbles.

• Anxiety and mood
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• v.10 no.2
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• pp.170-175
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• 2014

Objective : The aims of this study was to evaluate relationship between body dissatisfaction, personality characteristic, and stress in young adults. Methods : One hundred and ninety five young, healthy, and normal participants filled out all 3 types of self-reported questionnaire, the Body Dysmorphic Disorder Examination-Self Report (Korean version of BDDE-SR ; K-BDDE-SR), Neuroticism, Extraversion, Openness-Five Factor Inventory (NEO-FFI) and Stress Scale of Korean version of the Depression Anxiety Stress Scale (K-DASS-21). Results : Out of the 195 participants, 30% (n=59) was male and 70% (n=136) was female. There was no statistical difference between high K-BDDE-SR group (K-BDDE-SR score 75 percentile or higher, n=50) and low K-BDDE-SR group (K-BDDE-SR score below than 75 percentile, n=145) in terms of weight, height, and BMI. In high K-BDDE-SR group, neuroticism was significantly higher than low K-BDDE-SR group, and extraversion, agreeableness, conscientiousness were significantly lower than low K-BDDE-SR group. Also, level of stress in high K-BDDE-SR group was significantly higher than low K-BDDE-SR group. Conclusion : Our study revealed that individual's with more body dissatisfaction were more neurotic and stressful. Thus, body dissatisfaction and diverse psychiatric diseases should be considered in treating neurotic and stressful young adults.

• Animal cells and systems
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• v.1 no.1
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• pp.77-80
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• 1997

DOantrolene is a primary specific therapeutic drug for prevention and treatment of malignant hyperthermia symptoms. The mechanisms underlying the therapeutic effects of the drug are not well understood. The present study aimed at the characterization of the effects of azumolene, a water soluble dantrolene analogue, on ryanodine binding to sarcoplasmic reticulum (SR) from normal and malign::lnt hyperthermia susceptible (MHS) swine muscles. Characteristics of $[^3H]ryanodine$ binding were clearly different between the two types of SR. Kinetic analysis of eH]ryanodine binding to SR in the presence of $2{\mu}M$ $Ca^{2+}$ showed that association constant $(K_{ryanodine}_7$ is significantly higher in MHS than normal muscle SR $(2.83 vs. 1.32{\times}10^7 M^{-1}$, whereas the maximal ryanodine binding capacity $(B_{max})$ is similar between the two types of SR. Addition of azumolene $(e.g. 400{\mu}M)$ did not significantly alter both $K_{ryanodine}$ and $B_{max}$ of $[^3H]$ryanodine binding in both types of SR, indicating that the azumolene effect was not on the ryanodine binding sites. Addition of caffeine activated $[^3H]$ ryanodine binding in both types of SR, and caffeine sensitivity was significantly higher in MHS muscle SR than normal muscle SR $(K_{caffeine}:3.24 vs. 0.82 {\times} 10^2 M^{-l}). Addition of azumolene $(e.g.400{\mu}M)$ decreased Kcaffeine without significant change in $B_{max}$ in both types of SR suggesting that azumolene competes with caffeine binding site(s). These results suggest that malignant hyperthermia symptoms are caused at least in part by greater sensitivity of the MHS muscle SR to the $Ca^{2+}$ release drug(s), and that azumolene can reverse the symptoms by reducing the drug affinity to $Ca^{2+}$ release channels.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.155-159
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• 1999

Marine bacteria inhibiting the growth of the diatom, Chaetoceros calcitrans were screened from seawater samples collected at south coast of Korea in 1996. Six strains were isolated from those samples. Among them, a bacterium SR-14 strain had the strongest inhibition activity against the alga. The selected SR-14 strain was identified as an Alteromonas sp. (supposed to be Alteromonas colwelliana) according to its biochemical results. Alteromonas sp. SR-14 was able to grow in raw seawater, aged seawater, Conwy medium for culture of microalgae and C. calcitrans culture filtrate. The host ranges of Alteromonas sp. SR-14 were C. calcitrans, C. muclleri and C. negracile among 10 species of diatom. All of the Chaetoceros spp. tested were inhibited by the Alteromonas sp. SR-14, However, the growth of the other genera in Bacillariophyceae was not inhibited.

• Korean Journal of Crystallography
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• v.7 no.2
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• pp.147-155
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• 1996

Floating Zone Image furnace with halogen lamps as heat source has been made and applied to the growth of high-Tc superconductor Bi2Sr2CaCu2O8. The manufactured crystal growth equipment is composed of holder unit for setting the halogen lamps at the focal point of the elliptical mirror, image furnace with maximum temperature of 1800℃ with 1kW halogen lamps, cooling unit, feeding unit for supplying source material to the molten zone, pulling unit for crystal growth, and the control unit in the range of 2mm/hr -40 mm/hr vertical movement and 15rpm - 12rpm rotation. Bi2Sr2CaCu2O8 fibers have been grown with 300W halogen lamps and characterized with XRD, SEM and EDS. The growth condition was air atmosphere, growth speed 3∼4mm/hr, rotation speed of upper and lower part 20∼25 rpm. The fiber was composed of 20∼25 rpm matrix phase and secondary phases such as (Sr,Ca)CuO2 and (Sr,Ca)2CuO3.

• The Korean Journal of Physiology
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• v.24 no.2
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• pp.281-291
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• 1990

The $Ca^{2+}-substitutional$ roles of strontium for the contractile processes were investigated in the rabbit renal artery. The contractions induced by either norepinephrine or high $K^+$ in the condition which intra- and extracellular $Ca^{2+}$ were replaced by $Sr^{2+}$, i.e. $Sr^{2+}-mediated$ contractions, were dose-dependent. And then the maximal amplitude of contraction, as compared with $Ca^{2+}-mediated$ contraction, was about 50% in norepinephrine and about 70% in high $K^+$. The $Sr^{2+}-mediated$ contractions were independent in the contraction by norepinephrine $(10^{-5}M)$ but dependent in those by high $K^+(100\;mM)$ on the extracellular $Sr^{2+}$ concentration. Also $Sr^{2+}-mediated$ contractions induced by norepinephrine were observed in the $Sr^{2+}-free$ Tyrode's solution. The $Sr^{2+}-mediated$ contractions induced by either norepinephrine or high $K^+$ were suppressed by verapamil, a $Ca^{2+}-channel$ blocker. By extracellular addition of $Sr^{2+}$, the $Ca^{2+}-mediated$ contractions induced by norepinephrine $(10^{-5}M)$ or 40 mM $K^+$ were inhibited but those by high $K^+(100\;mM)$ were increased. And the $Sr^{2+}-mediated$ contractions were increased by extracellular addition of $Ca^{2+}$ but did not reach the level of $Ca^{2+}-mediated$ contraction. Therfore it is suggested that in the vascular smooth muscle of rabbit renal artery $Sr^{2+}$ could enter the smooth muscle cells easily through the potential-operated calcium channel (POC) but not easily through the receptor-operated calcium channel (ROG), and $Sr^{2+}$ might be stored in the intracellular $Ca^{2+}-binding$ site and released by NE and induced the contraction by a way of activating directly the contractile apparatus.

• Journal of Microbiology
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• v.35 no.3
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• pp.200-205
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• 1997

Bothl $Ca^{2+}$ and Sr$^{2+}$-containing methanol dehydrogenases (MDH) were purified to homogeneity with yields of 48% and 42%, respectively, from Methylabacillus methanolovorus sp. strain SK5. Most of the biochemical and structural properties were similar to each other. However, some differences were found: (1) although the overall shape of the absorption spectrum of Sr$^{2+}$-MDH was very similar to that of $Ca^{2+}$-MDH, the absorption intensity originating from the cofactor in Sr$^{2+}$. MDH was higher than that in $Ca^{2+}$-MDH. Small blue shift of the maximum was also observed. These are probably due to a difference in redox state of the cofactors in $Ca^{2+}$ and Sr$^{2+}$-MDH; (2) Sr$^{2+}$-MDH was more heat-stable than $Ca^{2+}$-MDH above 56$^{\circ}C$; (3) the V$_{max}$ values for the methanol-dependent activities of Sr$^{2+}$- and $Ca^{2+}$-MDH in the presence of 3 mM KCN were 2.038 and 808 nmol/mg protein/min, respectively. In addition, the $K_{m}$ values of Sr$^{2+}$ and $Ca^{2+}$ MDH for methanol were 12 and 21 $\mu$M, respectively; (4) the endogenous activity of $Ca^{2+}$-MDH was more sensitive than that of Sr$^{2+}$-MDH in the presence of cyanide; (5) Diethyl pyrocarbonate treatment increased the enzyme activities of $Ca^{2+}$- and Sr$^{2+}$-MDH 4.2- and 1.4-folds, respectively. These results indicate that Sr$^{2+}$ stabilizes the structural conformation and enhances the activity of MDH more than $Ca^{2+}$.

• Journal of Microbiology and Biotechnology
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• v.32 no.9
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• pp.1168-1177
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• 2022

Parkinson's disease (PD) is the second-most prevalent neurodegenerative disease and is characterized by dopaminergic neuronal death in the midbrain. Recently, the association between alterations in PD pathology and the gut microbiota has been explored. Microbiota-targeted interventions have been suggested as a novel therapeutic approach for PD. Agathobaculum butyriciproducens SR79^T (SR79) is an anaerobic bacterium. Previously, we showed that SR79 treatment induced cognitive improvement and reduced Alzheimer's disease pathologies in a mouse model. In this study, we hypothesized that SR79 treatment may have beneficial effects on PD pathology. To investigate the therapeutic effects of SR79 on PD, 6-hydroxydopamine (6-OHDA)-induced mouse models were used. D-Amphetamine sulfate (d-AMPH)-induced behavioral rotations and dopaminergic cell death were analyzed in unilateral 6-OHDA-lesioned mice. Treatment with SR79 significantly decreased ipsilateral rotations induced by d-AMPH. Moreover, SR79 treatment markedly activated the AKT/GSK3β signaling pathway in the striatum. In addition, SR79 treatment affected the Nrf2/ARE signaling pathway and its downstream target genes in the striatum of 6-OHDA-lesioned mice. Our findings suggest a protective role of SR79 in 6-OHDA-induced toxicity by regulating the AKT/Nrf2/ARE signaling pathway and astrocyte activation. Thus, SR79 may be a potential microbe-based intervention and therapeutic strategy for PD.

• Journal of the Korean Ceramic Society
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• v.21 no.4
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• pp.341-348
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• 1984

$BaTiO_3$ and $SrTiO_3$ were mixed with the mole ratio of 35:65， 50:50 and 65:35 and heated at 1100~120$0^{\circ}C$ for 1~64 hours. The dielectrics of $BaTiO_3$-$SrTiO_3$ system were investigated as a function of amount of solid solution formed. The dielectric constant was increased and Curie temperature was shifted to higher temperature with increasing of heating of soaking time for the same composition and heating temperature. This can be explained by the homogeneous distribution of $Ba^{2+}$ and $Sr^{2+}$ ion in the $BaTiO_3$ system. The Curie temperature was shifted to lower temperature with increasing $SrTiO_3$ in the $BaTiO_3$-$SrTiO_3$system because of decreasing the lattice constant.