• Journal of Microbiology and Biotechnology
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• v.11 no.4
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• pp.614-618
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• 2001

Low-threshold T-type $Ca^{2+}$ channels are distinctive voltage-operated gates for external $Ca^{2+}$ entry around a resting membrane potential due to their low voltage activation. These phenomena have already been extensively studied due to their relevance in diverse physiological functions. Recently, three T-type $Ca^{2+}$ channel ${\alpha}$$_1$subunits were cloned and their biophysical properties were characterized after expression in mammalian expression systems. In this study, ${\alpha_IG} and {\alpha_IH}$ low-threshold $Ca^{2+}$ channels were expressed and characterized in Xenopus oocytes after adding 5' and 3'untranslated portions of a Xenopus ${\beta}$ globin to improve their expression levels. The added portions dramatically enhanced the expression levels of the ${\alpha_IG} and {\alpha_IH}$ T-type channels. When currents were recorded in 10 mM $Ba^{2+}$ as the charge carrier, the activation thresholds were about -60 mV, peak currents appeared at -20 mV, and the reversal potentials were between +40 and +45. The activation time constants were very similar to each other, while the inactivation time constants of the ${\alpha_IG}$ currents were smaller than those of ${\alpha_IH}$. Taken together, the electrophysiological properties of the ${\alpha_IG} and {\alpha_IH}$ channels expressed in Xenopus oocytes were similar to the previously reported characteristics of low-threshold $Ca^{2+}$ channel currents.

• Korean Journal of Materials Research
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• v.24 no.9
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• pp.481-487
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• 2014

The effect of alpha phase on the fatigue properties of Fe-29%Ni-17%Co low thermal expansion alloy was investigated. Two kinds of alloys (Base alloy and Alpha alloy) were prepared by controlling the minimal alloy composition. Microstructure observation, tensile, high-cycle fatigue, and low-cycle fatigue results were measured in this study. The Base alloy microstructure showed typical austenite ${\gamma}$ phase. Alpha alloy represented the dispersed phase in the austenite ${\gamma}$ matrix. As a result of tensile testing, Alpha alloy was found to have higher strengths (Y.S. & T.S.) and lower elongation compared to those of the Base alloy. High cycle fatigue results showed that Alpha alloy had a higher fatigue limit (360MPa) than that (330MPa) of the Base alloy. The Alpha alloy exhibited the superior high cycle fatigue property in all of the fatigue stress conditions. SEM fractography results showed that the alpha phase could act to effectively retard both fatigue crack initiation and crack propagation. In the case of low-cycle fatigue, the Base alloy had longer fatigue life in the high plastic strain amplitude region and the Alpha alloy showed better fatigue property only in the low plastic strain amplitude region. The fatigue deformation behavior of the Fe-29%Ni-17%Co alloy was also discussed as related with its microstructure.

• BMB Reports
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• v.31 no.6
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• pp.595-599
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• 1998

To investigate conformational information of a low oxygen affinity recombinant hemoglobin (rHb) containing $96Val{\rightarrow}Trp$ mutation at the ${\alpha}96$ position, we ave produced rHb (${\alpha}96Val{\rightarrow}Phe$) and rHb (${\alpha}96Val{\rightarrow}Tyr$), using the Escherichia coli expression system and site-directed mutagenesis. The oxygen affinity of rHb (${\alpha}96Val{\rightarrow}Phe$) is similar to that of human normal adult hemoglobin (Hb A). However, the oxygen affinity of rHb (${\alpha}96Val{\rightarrow}Tyr$) showed much lower oxygen affinity than Hb A which is similar to that of rHb (${\alpha}96Val{\rightarrow}Tyr$), providing an opportunity as a potential candidate for a hemoglobin-based blood substitute. Both rHb (${\alpha}96Val{\rightarrow}Phe$) and rHb (${\alpha}96Val{\rightarrow}Tyr)$ showed high cooperativity in oxygen binding. IH-NMR spectroscopy shows that both rHb (${\alpha}96Val{\rightarrow}Phe$) and rHb (${\alpha}96Val{\rightarrow}Tyr$) have very similar tertiary structure around the heme pockets and uaternary structure in the ${\alpha}_1/{\beta}_2$ subunit interface ompared to Hb A. The low oxygen affinity of rHb (${\alpha}96Val{\rightarrow}Tyr$) has been suggested to be due to a hydrogen bond caused by an extra hydroxyl group not present in rHb (${\alpha}96Val{\rightarrow}Phe$). However, investigation of the carbonmonoxy form of rHb (${\alpha}96Val{\rightarrow}Phe$) and (${\alpha}96Val{\rightarrow}Try$) in the presence of inositol hexaphosphate at low temperature suggests that low oxygen affinity of (${\alpha}96Val{\rightarrow}Try$) may arise from a mechanism different to that of rHb (${\alpha}96Val{\rightarrow}Trp$).

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.76-79
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• 2009

The current understanding for phase/grain boundary sliding and low-temperature/high-strain rate superplasticity of two-phase titanium alloys is summarized. The quantitative analysis on boundary sliding revealed increased sliding resistance on the order of $\alpha/\beta\;\ll\;\alpha/\alpha\;\approx\;\beta/\beta$ boundary, hence, led to the conclusion that approximately 50% alpha(or beta) volume fraction and/or grain refinement is beneficial for obtaining large superplastic elongation at low temperature and/or high strain rate. To predict the temperature for 50% alpha volume in various alpha/beta Ti, artificial neural network was applied. Finally, much enhanced superplasticity was achieved through grain refinement utilizing dynamic globularization.

• Journal of Embryo Transfer
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• v.22 no.1
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• pp.27-32
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• 2007

This study was conducted to examine the effects of prostaglandin $F_2{\alpha}(PGF_2{\alpha})$ and prostaglandin $E_2 (PGE_2)$ on the expansion and hatching of bovine embryos. During the in vitro culture, embryos were cultured with the following groups: (1) 0, 1, 10 and 100ng/ml $PGF_2{\alpha}$ (2) 0, 1, 10 and 100 ng/ml $PGF_2{\alpha}$, (3) low concentration of $PGF_2{\alpha}$ ; low concentration of $PGF_2{\alpha}$, (1ng/ml : 1ng/ml), (4) low concentration of $PGF_2{\alpha}$ : high concentration of $PGF_2{\alpha}$ (1ng/ml : 10ng/ml) (5) high concentration of $PGF_2{\alpha}$ : low concentration of $PGE_2$ (10ng/ml 1ng/ml) (6) high concentration of $PGF_2{\alpha}$ : high concentration of $PGE_2$(10 ng/ml : 10ng/ml). In the results of this study, treatment of $PGF_2{\alpha}$ or $PGE_2$ did not affect in vitro development to blastocysts. However, the hatching rates of embryos cultured with 10ng/ml $PGE_2$(10.3%) and 1ng/ml $PGF_2{\alpha}$ 10ng/ml $PGE_2$(22.2%) were significantly (P<0.05) higher than in control (4.3% and 12.7%) and other treatment groups. All groups treated with high concentrations of $PGF_2{\alpha}$ showed decreased hatching rates. Thus, this results suggested that $PGF_2{\alpha}\;and\;PGE_2$ were concerned with the hatching in bovine embryos, and their effects on hatching were different by the concentrations.

• Journal of Korean Physical Therapy Science
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• v.18 no.3
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• pp.53-61
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• 2011

Purpose : his study was to analyze the reliability and validity on Oswestry Low Back Pain Disability Index (OLBPDI) in patients with low back pain. Methods : The sample consisted of 211 patients who had received treatments at the physical therapy units of 3 medical institutions from February to December 2008 in Andong city. Questionnaires on the OLBPDI were recruited by 6 physical therapists. The internal structure and reliability of the scales were evaluated by means of item-internal consistency(Cronbach's alpha coefficient:${\alpha}$), item-discriminant validity, Pearson's relation coefficient. Results : An average of patients's age was 41.1 years. The range of OLBPDI subscales were .93~.94 in Cronbach's ${\alpha}$. The internal consistency reliability of total item-each item were also internally consistent with Cronbach's ${\alpha}$ range of .94~.95(Pearson's correlation coefficient range: .62~.89). However, high correlation were obtained among 10 items(.67~.83), therefore the item-discriminant validity was a little low. Conclusion: In conclusion, the results reported here confirm the reliability of the OLBPDI scales in patients with low back pain. The collection of information on the level of disability due to low back pain using this instrument was acceptable to patients. A further prospective multi-center study will be necessary to prove the reliability and validity.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.331-339
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• 2001

Zero to tension fatigue tests and strain controlled fatigue tests were carried out to find how initial strain induced martensite, ${\alpha}^{\prime}$ affects low and high cycle fatigue behavior and fatigue crack growth mechanisms. Microscopic study and phase analysis were carried out with TEM, SEM, EDAX, Optical Microscope, Ferriscope, and X-ray diffractometry. The amount of Initial ${\alpha}^{\prime}$ was controlled from 0% to 33% by controlling the temperatures for cold working and heat treatment. Lower contents of initial ${\alpha}^{\prime}$ showed higher fatigue resistance in low cycle fatigue but lower fatigue resistance in high cycle fatigue because it is ascribed to the more transformation of ${\alpha}^{\prime}$ martensite during low cycle fatigue and higher ductility. In high cycle fatigue, fatigue life is attributed to the strength and phase transformation of austenite into ${\alpha}^{\prime}$ during fatigue was negligible. ${\gamma}$ boundary, ${\gamma}/twin$ boundary, and ${\gamma}/{\alpha}^{\prime}$ boundary were found to be the preferred site of fatigue crack initiation.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.4
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• pp.7-14
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• 2015

Research and application of three dimensional packaging technology in electronics have been increasing according to the trend of high density, high capacity and light weight in electronics. In this paper, TSV fabrication and research trend in three dimensional packaging are reported. Low alpha solder bumping which can solve the soft error problem in electronics is also introduced. In detail, this paper includes fabrication of TSV, functional layers deposition, Cu filling in TSV by electroplating using PPR (periodic pulse reverse) and 3 step PPR processes, and low alpha solder bumping on TSV by solder ball. TSV and low alpha solder bumping technologies need more studies and improvements, and the drawbacks of three dimensional packaging can be solved gradually through continuous attentions and researches.

• Journal of Veterinary Clinics
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• v.29 no.5
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• pp.361-367
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• 2012

Diabetes-related complications in human and veterinary medicine have been shown to be associated with hyperglycemia-induced inflammation. It has been recently suggested that the onset of insulin resistance may be caused by over-production of inflammatory cytokines such as tumor necrosis factor (TNF)-${\alpha}$ from immune cells. Conjugated linoleic acid (CLA) regulates inflammatory response through modulation of TNF-${\alpha}$ expression. The objective of this study was to examine the effect of CLA on nuclear factor kappaB (NF-${\kappa}B$) p65 binding activity, inhibitory kappaB ($I{\kappa}B$)-${\alpha}$ expression, and TNF-${\alpha}$ production from high glucose-treated RAW 264.7 cells. CLA was added to RAW cells that had been previously cultured with low or high concentration of glucose. The levels of TNF-${\alpha}$ protein in the culture supernatant of RAW cells exposed to high concentrations of glucose were higher than those of cells exposed to low concentrations of glucose. The treatment with the high concentration of glucose in RAW cells increased levels of NF-${\kappa}B$ p65 binding activity and the decreased $I{\kappa}B-{\alpha}$ expression when compared with those of low glucose. The treatments in combination with CLA and glucose (low and high) glucose in RAW cells increased TNF-${\alpha}$ production when compared with that glucose alone. These treatments with CLA increased TNF-${\alpha}$ production in high glucose-treated RAW cells than those with low glucose. These treatments of CLA also showed higher NF-${\kappa}B$ p65 binding activity and lower $I{\kappa}B-{\alpha}$ expression in high glucose than those in low glucose condition. This suggests that CLA can increase NF-${\kappa}B$ p65 binding activity and TNF-${\alpha}$ production from high glucose-treated RAW 264.7 cells and is likely to promote hyperglycemia-induced inflammation.

• Elastomers and Composites
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• v.45 no.3
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• pp.152-155
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• 2010

Olefinic thermoplastic elastomer and styrenic thermoplastic elastomer have broad hardness range, high flexibility, low density, and excellent recyclability. But, they are limited in applications due to their low elasticity and low operating temperature. To overcome these problems, olefin/styrene or olefin/$\alpha$-olefin copolymers have been developed. In this review, we described some examples of olefin/styrene or olefin/$\alpha$-olefin copolymer and introduced their properties. Although olefin/styrene or olefin/$\alpha$-olefin copolymer have various weaknesses, they have a great potential in the future.