• Korean Journal of Crystallography
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• v.8 no.1
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• pp.26-32
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• 1997

Quartz single crystals were grown hydrothermally and growth defects such as dislocations, etch channels and impurities were examined. Growth rates were 0.25-0.65 mm/day under the growth conditions of following. 1. Mineralizer: $4wt.\%$ NaOH. 2. Growth temperature: $340-360^{\circ}C$. 3. Temperature gradient: $20-40^{\circ}C$. 4. Seed: ZY plate. 5. Nutrient: synthetic quartz. Defects of the quartz which was grown with optical grade synthetic nutrient, low dislocation density seed and horizontal seed setting technique were as follows. 1. Dislocation density: 20.0 each/$cm^2$. 2. Etch channel density: 5.0 each/$cm^2$ (1st grade by IEC 758 standard). 3. Impurity (larger than 10$\mu$) concentration: 2.4 each/$cm^3$ (Ia grade by IEC 758 standard). 4. Alpha value: 0.019 (A grade by IEC 758 standard).

• The Journal of Internal Korean Medicine
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• v.22 no.2
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• pp.119-125
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• 2001

Objectives : This study was conducted to evaluate the effect and mechanism of Geupoongjibo-dan's relaxation of the tension of the blood vessel caused by Phenylephrine and KCI. Methods : In order to study the effect of Geupoongjibo-dan's relaxation of the blood vessel tension, Geupoongjibo-dan extract was infused into Phenylephrine and KCI-induced contracted rabbit aorta strips. To analyze the mechanism of Geupoongjibo-dan's effect on the blood vessel, Geupoongjibo-dan extract infused into Phenylephrine and KCI-induced contracted strips induced by agonists after treatment of N${\omega}$-nitro-L-arginine, Methylene Blue. Results : 1. Geupoongjibo-dan was very effective in relaxing the blood vessels contracted by Phenylephrine. 2. Geupoongjibo-dan was effective against Phenylephrine, than against KCI. 3. Geupoongjibo-dan's more relaxation effect on a blood vessel was terminated by N${\omega}$-nitro-L-arginine and methylene treatment. Conclusion : THis study showed that Geupoongjibo-dan's relaxation effect on a blood vessel is irrelevant to ${\alpha}$-adrenalin receptor, and it relaxes contracted vessels through cGMP channel.

• Journal of Nutrition and Health
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• v.50 no.3
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• pp.217-224
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• 2017

Purpose: Although it is well known thatmortality and morbidity due to cardiovascular diseases are higher in salt-sensitive subjects than in salt-resistant subjects, their underlying mechanisms related to obesity remain unclear. Here, we focused on salt-sensitive gene variants unrelated to monogenic obesity that interacted with sodium intake in humans. Methods: This review was written based on the modified $3^rd$ step of Khans' systematic review. Instead of the literature, subject genes were based on candidate genes screened from our preliminary Genome-Wide Association Study (GWAS). Finally, literature related to five genes strongly associated with salt sensitivity were analyzed to elucidate the mechanism of obesity. Results: Salt sensitivity is a measure of how blood pressure responds to salt intake, and people are either salt-sensitive or salt-resistant. Otherwise, dietary sodium restriction may not be beneficial for everyone since salt sensitivity may be associated with inherited susceptibility. According to our previous GWAS studies, 10 candidate genes and 11 single nucleotide polymorphisms (SNPs) associated with salt sensitivity were suggested, including angiotensin converting enzyme (ACE), ${\alpha}$-adducin1 (ADD1), angiotensinogen (AGT), cytochrome P450 family 11-subfamily ${\beta}$-2 ($CYP11{\beta}$-2), epithelial sodium channel (ENaC), G-protein b3 subunit (GNB3), G protein-coupled receptor kinases type 4 (GRK4 A142V, GRK4 A486V), $11{\beta}$-hydroxysteroid dehydrogenase type-2 (HSD $11{\beta}$-2), neural precursor cell-expressed developmentally down regulated 4 like (NEDD4L),and solute carrier family 12(sodium/chloride transporters)-member 3 (SLC 12A3). We found that polymorphisms of salt-sensitive genes such as ACE, $CYP11{\beta}$-2, GRK4, SLC12A3, and GNB3 may be positively associated with human obesity. Conclusion: Despite gender, ethnic, and age differences in genetics studies, hypertensive obese children and adults who are carriers of specific salt-sensitive genes are recommended to reduce their sodium intake. We believe that our findings can contribute to the prevention of early-onset of chronic diseases in obese children by facilitating personalized diet-management of obesity from childhood to adulthood.

• Biomolecules & Therapeutics
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• v.27 no.1
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• pp.101-106
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• 2019

Most diabetic patients experience diabetic mellitus (DM) urinary bladder dysfunction. A number of studies evaluate bladder smooth muscle contraction in DM. In this study, we evaluated the change of bladder smooth muscle contraction between normal rats and DM rats. Furthermore, we used pharmacological inhibitors to determine the differences in the signaling pathways between normal and DM rats. Rats in the DM group received an intraperitoneal injection of 65 mg/kg streptozotocin and measured blood glucose level after 14 days to confirm DM. Bladder smooth muscle contraction was induced using acetylcholine (ACh, $10^{-4}M$). The materials such as, atropine (a muscarinic receptor antagonist), U73122 (a phospholipase C inhibitor), DPCPX (an adenosine $A_1$ receptor antagonist), udenafil (a PDE5 inhibitor), prazosin (an ${\alpha}_1$-receptor antagonist), papaverine (a smooth muscle relaxant), verapamil (a calcium channel blocker), and chelerythrine (a protein kinase C inhibitor) were pre-treated in bladder smooth muscle. We found that the DM rats had lower bladder smooth muscle contractility than normal rats. When prazosin, udenafil, verapamil, and U73122 were pre-treated, there were significant differences between normal and DM rats. Taken together, it was concluded that the change of intracellular $Ca^{2+}$ release mediated by PLC/IP3 and PDE5 activity were responsible for decreased bladder smooth muscle contractility in DM rats.

• The Journal of Advanced Prosthodontics
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• v.11 no.2
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• pp.105-111
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• 2019

PURPOSE. Limited data is available regarding the differences for possible microleakage problems and fitting accuracy of zirconia versus titanium abutments with various connection designs. The purpose of this in vitro study was to investigate the effect of connection design and abutment material on the sealing capability and fitting accuracy of abutments. MATERIALS AND METHODS. A total of 42 abutments with different connection designs [internal conical (IC), internal tri-channel (IT), and external hexagonal (EH)] and abutment materials [titanium (Ti) and zirconia (Zr)] were evaluated. The inner parts of implants were inoculated with $0.7{\mu}L$ of polymicrobial culture (P. gingivalis, T. forsythia, T. denticola and F. nucleatum) and connected with their respective abutments under sterile conditions. The penetration of bacteria into the surrounding media was assessed by the visual evaluation of turbidity at each time point and the number of colony forming units (CFUs) was counted. The marginal gap at the implant- abutment interface (IAI) was measured by scanning electron microscope. The data sets were statistically analyzed using Kruskal-Wallis followed by Mann-Whitney U tests with the Bonferroni-Holm correction (${\alpha}=.05$). RESULTS. Statistically significant difference was found among the groups based on the results of leaked colonies (P<.05). The EH-Ti group characterized by an external hexagonal connection were less resistant to bacterial leakage than the groups EH-Zr, IT-Zr, IT-Ti, IC-Zr, and IC-Ti (P<.05). The marginal misfit (in ${\mu}m$) of the groups were in the range of 2.7-4.0 (IC-Zr), 1.8-5.3 (IC-Ti), 6.5-17.1 (IT-Zr), 5.4-12.0 (IT-Ti), 16.8-22.7 (EH-Zr), and 10.3-15.4 (EH-Ti). CONCLUSION. The sealing capability and marginal fit of abutments were affected by the type of abutment material and connection design.

• BMB Reports
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• v.54 no.9
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• pp.464-469
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• 2021

Cardiomyocyte differentiation occurs through complex and finely regulated processes including cardiac lineage commitment and maturation from pluripotent stem cells (PSCs). To gain some insight into the genome-wide characteristics of cardiac lineage commitment, we performed transcriptome analysis on both mouse embryonic stem cells (mESCs) and human induced PSCs (hiPSCs) at specific stages of cardiomyocyte differentiation. Specifically, the gene expression profiles and the protein-protein interaction networks of the mESC-derived platelet-derived growth factor receptor-alpha (PDGFRα)⁺ cardiac lineage-committed cells (CLCs) and hiPSC-derived kinase insert domain receptor (KDR)⁺ and PDGFRα⁺ cardiac progenitor cells (CPCs) at cardiac lineage commitment were compared with those of mesodermal cells and differentiated cardiomyocytes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed that the genes significantly upregulated at cardiac lineage commitment were associated with responses to organic substances and external stimuli, extracellular and myocardial contractile components, receptor binding, gated channel activity, PI3K-AKT signaling, and cardiac hypertrophy and dilation pathways. Protein-protein interaction network analysis revealed that the expression levels of genes that regulate cardiac maturation, heart contraction, and calcium handling showed a consistent increase during cardiac differentiation; however, the expression levels of genes that regulate cell differentiation and multicellular organism development decreased at the cardiac maturation stage following lineage commitment. Additionally, we identified for the first time the protein-protein interaction network connecting cardiac development, the immune system, and metabolism during cardiac lineage commitment in both mESC-derived PDGFRα⁺ CLCs and hiPSC-derived KDR⁺PDGFRα⁺ CPCs. These findings shed light on the regulation of cardiac lineage commitment and the pathogenesis of cardiometabolic diseases.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.1062-1070
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• 2022

In the present communication, pure and stable α-Bismuth Oxide (Bi₂O₃) nanoparticles (NPs) were synthesized by low temperature solution combustion method using urea as a fuel and calcined at 500℃. The synthesized sample was characterized by using powder X-ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), Energy dispersive X-ray analysis (EDAX), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and UV-Visible absorption spectroscopy. The PXRD pattern confirms the formation of mono-clinic, stable and low temperature phase α-Bi₂O₃. The direct optical energy band gap was estimated by using Wood and Tauc's relation which was found to be 2.81 eV. The characterized sample was studied for X-ray/gamma ray shielding properties in the energy range 0.081-1.332 MeV using NaI (Tl) detector and multi channel analyzer (MCA). The measured shielding parameters agrees well with the theory, whereas, slight deviation up to 20% is observed below 356 keV. This deviation is mainly due to the influence of atomic size of the target medium. Furthermore an accurate theory is necessary to explain the interaction of X-ray/gamma ray with the NPs.The present work opens new window to use this facile, economical, efficient, low temperature method to synthesize nanomaterials for X-ray/gamma ray shielding purpose.

• Korean journal of applied entomology
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• v.61 no.1
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• pp.117-128
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• 2022

In this study, we have examined pyrethroid actions on sodium channels in the pest insect Heliothis virescens. The synthetic pyrethroid permethrin increased steady-state sodium current in H. virescens central neurons and prolonged tail currents (I_Na-tail) due to extreme slowing of sodium channel deactivation. Prolongation of I_Na-tail was evident at permethrin concentrations as low as 60 nM, which modified ~1.7% of sodium channels and 10 μM permethrin modified about 30% of channels. The average time constant (τ₁) of tail current decay was ~335 ms for permethrin-modified channels. These modified channels activated at more negative potentials and showed slower activation kinetics, and failed to inactivate. Permethrin modification of sodium channels was dramatically potentiated by the α scorpion toxin LqhαIT, showing positive cooperativity between two binding sites. The amplitude of the tail current induced by 0.3 μM permethrin was enhanced ~8-fold by LqhαIT (200 pM). Positive cooperativity was also observed between permethrin and the insect-specific scorpion toxin AaIT as 10 nM permethrin potentiated the shift of voltage dependence caused by AaIT (~2-fold).

• The Korean Journal of Physiology
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• v.23 no.2
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• pp.263-275
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• 1989

Mechanical contractions and electrical activities of the fundic longitudinal and antral circular muscle fibers were investigated in order to elucidate topical differences of gastric motility. K-induced contracture was produced by exposure of muscle strips to high K Tyrode solution. Membrane potential and mechanical contraction were simultaneously recorded by conventional glass microelectrode method and single sucrose-gap technique. All experiments were performed in tris-buffered Tyrode solution which was aerated with $100%\;O_2\;and\;kept\;35^{\circ}C$. The results obtained were as follows: 1) The resting membrane potential of circular muscle cells in the antral region was about 10 mV more negative than that in the fundic region. 2) The membrane potentials decreased almost linearly as the extracellular KCI concentration was increased both in antral circular muscle cells and in fundic longitudinal muscle cells. 3) The thresholdal K concentration of K-contracture was 15 mM (membrane potential, -48 mV) for the antral circular muscle strip and 20 mM for the fundic longitudinal muscle cells. 4) The ratio of membrane permeability coefficient for $Na^+\;and\;K^+,\;P_{Na}/P_K\;({\alpha})$ was 0.065 for antral circular muscle cells and was 0.108 for fundic longitudinal muscle cells. 5) K-contracture of antral and fundic smooth muscle strips showed the contracture composed of phasic and tonic components. The amplitude of the phasic component increased sigmoidally in a dose-dependent manner, whereas that of the tonic component was maximal at a concentration of 40 mM KCI and at the concentrations above or below 40 mM KCI the amplitude was reduced. 6) The inverse relationship between the amplitude of tonic component and extracellular KCI concentration in the range of 40 to 150 mM KCI was more prominent in the antral circular muscle strip than in the fundic longitudinal muscle strip, where the amplitude of the tonic component decreased less steeply and was maintained higher at the same high K concentrations. 7) The tonic component was totally dependent on the external $Ca^{2+}$ and completely abolished by verapamil, while tile phasic component was far less dependent on the external $Ca^{2+}$ and partially suppressed by verapamil. From the above results, the following conclusions could be made. 1) The phasic component of K-contracture is produced both by intracellular $Ca^{2+}$ mobilization and by $Ca^{2+}$-influx from outside, while the tonic component is generated and maintained by the $Ca^{2+}-influx$ through the potential-dependent $Ca^{2+}$ channel. 2) The mechanism of reducing the free $Ca^{2+}$ concentration in the myoplasm seems to be more developed in the antral circular muscle than in the fundic longitudinal muscle. 3) The lower resting membrane potential of the fundic longitudinal muscle cell reflects a relatively high $P_{Na}/P_K$ ratio of about 0.108.

• Genomics & Informatics
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• v.10 no.2
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• pp.110-116
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• 2012

Recent several studies have shown that the genetic variation of SCN5A is related with atrioventricular conduction block (AVB); no study has yet been published in Koreans. Therefore, to determine the AVB-associated genetic variation in Korean patients, we investigated the genetic variation of SCN5A in Korean patients with AVB and compared with normal control subjects. We enrolled 113 patients with AVB and 80 normal controls with no cardiac symptoms. DNA was isolated from the peripheral blood, and all exons (exon 2-exon 28) except the untranslated region and exon-intron boundaries of the SCN5A gene were amplified by multiplex PCR and directly sequenced using an ABI PRISM 3100 Genetic Analyzer. When a variation was discovered in genomic DNA from AVB patients, we confirmed whether the same variation existed in the control genomic DNA. In the present study, a total of 7 genetic variations were detected in 113 AVB patients. Of the 7 variations, 5 (G87A-A29A, intervening sequence 9-3C>A, A1673G-H558R, G3578A-R1193Q, and T5457C-D1819D) have been reported in previous studies, and 2 (C48G-F16L and G3048A-T1016T) were novel variations that have not been reported. The 2 newly discovered variations were not found in the 80 normal controls. In addition, G298S, G514C, P1008S, G1406R, and D1595N, identified in other ethnic populations, were not detected in this study. We found 2 novel genetic variations in the SCN5A gene in Korean patients with AVB. However, further functional study might be needed.