• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.504-509
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• 2018

The purpose of this study was to manufacture a high-performance titanium yellow pigment. Anatase type $TiO_2$ was the skeleton of the pigment and $Sb_2O_3$ is used as the color assistant for the coloring agent, $Cr_2O_3$. Mixed raw materials for the pigment were $TiO_2$(98%), $Sb_2O_3$(99.5%), and $Cr_2O_3$(99.5%). The raw materials were mixed by a dry process and crystallized by calcination at $1,000{\sim}1,200^{\circ}C$. The crystalline material was pulverized in a Jar Mill under $1{\mu}m$ by a wet process and dried for 12 hours at $100^{\circ}C$. The pigment was finally made by a fine grinding process. To determine the best temperature for calcination, 4 temperature sections ($1000^{\circ}C$, $1100^{\circ}C$, $1150^{\circ}C$, and $1200^{\circ}C$) were set up. The X-ray diffraction peak of the rutile crystalline structure was highest at $1,150^{\circ}C$. The yellow ceramic pigment, which has the rutile structure, was applied for coating materials. The synthesized pigments underwent a discoloration tests on the acid resistance, alkaline resistance, weather resistance and heat resistance. In addition, a detection test on harmful heavy metals ($Cr^{+6}$) was done. The resulting values (${\Delta}E$) of the weather resistance test (2000hr), acid resistance test, alkaline resistance test, and heat resistance test were 0.74, 0.16, 0.07 and 0.29. The resulting value for heavy metals testing was 34ppm.

• Restorative Dentistry and Endodontics
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• v.34 no.2
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• pp.154-161
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• 2009

This clinical study evaluated the whitening effect and safety of polymer based-pen type BlancTis Forte (NIBEC) containing 8.3% carbamide peroxide. Twenty volunteers used the BlancTis Forte whitening agent for 2 hours twice a day for 4 weeks. As a control. Whitening Effect Pen (LG) containing 3% hydrogen peroxide was used by 20 volunteers using the same protocol. The change in shade (${\Delta}E^*$, color difference) was measured using $Shadepilot^{TM}$ (DeguDent) before, during, and after bleaching (2 weeks, 4 weeks, and post-bleaching 4 weeks). A clinical examination for any side effects (tooth hypersensitivity or soft tissue complications) was also performed at each check-up. The following results were obtained. 1. Both the experimental and control groups displayed a noticeable change in shade (${\Delta}E$) of over 2. No significant differences were found between the two groups (p > 0.05), implying that the two agents have a similar whitening effect.2. The whitening effect was mainly due to changes in a and b values rather than in L value (brightness). The experimental group showed a significantly higher change in b value, thus yellow shade, than the control (p < 0.05). 3. None of the participants complained of tooth hypersensitivity or soft tissue complications, confirming the safety of both whitening agents.

• International Journal of Oral Biology
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• v.34 no.4
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• pp.191-197
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• 2009

Somatostatin (SST) is a known neuromodulator of the central nervous system. The substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc) receives many thinmyelinated $A{\delta}$-fiber and unmyelinated C primary afferent fibers and is involved in nociceptive processing. Many studies have demonstrated that SST plays a pivotal role in pain modulation in the spinal cord. However, little is yet known about the direct effects of SST on the SG neurons of the Vc in adult mice. In our present study, we investigated the direct membrane effects of SST and a type 2 SST receptor agonist, seglitide (SEG), on the SG neurons of the Vc using a gramicidin-perforated current clamp in adult mice. The majority (53%, n = 27/51) of the adult SG neurons were hyperpolarized by SST (300 nM) but no differences were found in the hyperpolarization response rate between males and females. When SST was applied successively, the second response was smaller ($76{\pm}9.5%$, n=19), suggesting that SST receptors are desensitized by repeated application. SST-induced hyperpolarization was also maintained under conditions where presynaptic events were blocked ($75{\pm}1.0%$, n=5), suggesting that this neuromodulator exerts direct effects upon postsynaptic SG neurons. SEG was further found to induce membrane hyperpolarization of the SG neurons of the Vc. These results collectively demonstrate that SST inhibits the SG neuronal activities of the Vc in adult mice with no gender bias, and that these effects are mediated via a type 2 SST receptor, suggesting that this is a potential target for orofacial pain modulation.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.9
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• pp.1225-1233
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• 2009

Fat composition of beef, taken here to mean marbling, can be manipulated by time on feed, finishing diet, and breed type. These three factors also strongly influence the fatty acid composition of beef. Both the amount of marbling and the concentration of monounsaturated fatty acids (MUFA) increase with time on feed in grain-fed and pasture-fed cattle, but much more dramatically in grain-fed cattle. High-concentrate diets stimulate the activity of adipose tissue stearoyl-CoA desaturase (SCD), which is responsible for the conversion of saturated fatty acids (SFA) to their $\Delta{9}$ desaturated counterparts. Also, grain feeding causes a depression in ruminal pH, which decreases those populations of ruminal microorganisms responsible for the isomerization and hydrogenation of polyunsaturated fatty acids (PUFA). The net result of elevated SCD activity in marbling adipose tissue and depressed ruminal isomerization/hydrogenation of dietary PUFA is a large increase in MUFA in beef over time. Conversely, pasture depresses both the accumulation of marbling and SCD activity, so that even though pasture feeding increases the relative concentration of PUFA in beef, it also increases SFA at the expense of MUFA. Wagyu and Hanwoo cattle accumulate large amounts of marbling and MUFA, and Wagyu cattle appear to be less sensitive to the effects of pastures in depressing overall rates of adipogenesis and the synthesis of MUFA in adipose tissues. There are small differences in fatty acid composition of beef from Bos indicus and Bos taurus cattle, but diet and time on feed are much more important determinants of beef fat content and fatty acid composition than breed type.

• Journal of Applied Biological Chemistry
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• v.57 no.4
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• pp.287-294
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• 2014

To improve the shelf life of low-salt Kochujang, Korean hot pepper paste, antimicrobial materials were added at different times before and after aging. The kochujang was then packaged and stored at $30^{\circ}C$ for 15 weeks, and changes in microbiological and physiochemical properties were evaluated. Hunter a- and b-values decreased considerably during storage. The total color difference (${\delta}E$) was greater in the ethanol-chitosan (EC) treatment than in the control and after pasteurization (A-P) treatment. Gas was produced until the seventh week of storage. The control and the A-P treatments produced more gas than the other treatments, and these had the largest number of yeasts and aerobic bacteria. The pH of the EC treatment was higher than that of the other treatments, and the A-P treatment had the highest level of titratable acidity. During storage, the oxidation-reduction potential was lower in the EC and ethanol-mustard-chitosan (EMC) treatments. The reducing sugar content decreased remarkably in the control and A-P treatments, with high production of ethanol. There was a significant change in the content of amino-type nitrogen in the control and A-P treatments, and the content of ammonia-type nitrogen was lowest in the EMC treatment. In the sensory test of kochujang, the ethanol-mustard (EM) and ethanol (E) treatments were significantly higher than the EC, control, and A-P treatments (p <0.05). EM or E alone was effective in extending the shelf life of kochujang when added before aging.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.159-161
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• 2005

Hypovirus infection of the chestnut blight fungus Cryphonectria parasitica is a useful model system to study the hypoviral regulation of fungal gene expression. The hypovirus is known to downregulate the fungal laccase1 (lac 1), the modulation of which is tightly governed by the inositol triphosphate ($IP_3$) and calcium second messenger system in a virus-free strain. We cloned the gene cplc1 encoding a phosphatidyl inositol-specific phospholipase C (PLC), in order to better characterize the fungal gene regulation by hypovirus. Sequence analysis of the cplc1 gene indicated that the protein product contained both the X and Y domains, which are the two conserved regions found in all known PLCs, with a 133 amino acid extension between the 2nd ${\beta}$-strand and the ${\alpha}$-helix in the X domain. In addition, the gene organization appeared to be highly similar to that of a ${\delta}$ type PLC. Disruption of the cplc1 gene resulted in slow growth and produced colonies characterized by little aerial mycelia and deep orange in color. In addition, down regulation of lac1 expression was observed. However, temperature sensitivity, osmosensitivity, virulence, and other hypovirulence-associated characteristics did not differ from the wild-type strain. Functional complementation of the cplc1-null mutant with the PLC1 gene from Saccharomyces cerevisiae restored lac1 expression, which suggests that the cloned gene encodes PLC activity. The present study indicates that the cplc1 gene is required for appropriate mycelial growth, and that it regulates the lac1 expression, which is also modulated by the hypovirus. Although several PLC genes have been identified in various simple eukaryotic organisms, the deletion analysis of the cplc1 gene in this study appears to be the first report on the functional analysis of PLC in filamentous fungi.

• Journal of Microbiology and Biotechnology
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• v.20 no.8
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• pp.1196-1203
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• 2010

In the present work, methanethiol and dimethyldisulfide were investigated as sulfur sources for methionine synthesis in Corynebacterium glutamicum. In silico pathway analysis predicted a high methionine yield for these reduced compounds, provided that they could be utilized. Wild-type cells were able to grow on both methanethiol and dimethyldisulfide as sole sulfur sources. Isotope labeling studies with mutant strains, exhibiting targeted modification of methionine biosynthesis, gave detailed insight into the underlying pathways involved in the assimilation of methanethiol and dimethyldisulfide. Both sulfur compounds are incorporated as an entire molecule, adding the terminal S-$CH_3$ group to O-acetylhomoserine. In this reaction, methionine is directly formed. MetY (O-acetylhomoserine sulfhydrylase) was identified as the enzyme catalyzing the reaction. The deletion of metY resulted in methionine auxotrophic strains grown on methanethiol or dimethyldisulfide as sole sulfur sources. Plasmid-based overexpression of metY in the ${\Delta}$metY background restored the capacity to grow on methanethiol or dimethyldisulfide as sole sulfur sources. In vitro studies with the C. glutamicum wild type revealed a relatively low activity of MetY for methanethiol (63 mU/mg) and dimethyldisulfide (61 mU/mg). Overexpression of metY increased the in vitro activity to 1,780 mU/mg and was beneficial for methionine production, since the intracellular methionine pool was increased 2-fold in the engineered strain. This positive effect was limited by a depletion of the metY substrate O-acetylhomoserine, suggesting a need for further metabolic engineering targets towards competitive production strains.

• Journal of the Korean Society of Safety
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• v.23 no.4
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• pp.13-18
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• 2008

This study deals with finish roll forming by forced displacement can be conceived as a method of eliminating errors in conventional form rolling under constant loads. This method produces a high-precision tooth profile by low-speed form rolling when a high rigid screw or cam is used at the pressurized section. Tooth profile is decided in the beginning of roll forming and ${\delta}_{max}$ mainly increases if the number of roll forming process is increased. Gear class is improved by one or two class after roll forming if the gear has convex type error and pressure angle error in KS 4 class. If the gear have concave type error and pressure angle error and pressure angle error, gear class is not improved in theory, but improved a little in practice. In the finishing roll forming, it inevitably yields both the concaving of tooth profile and plastic deflection of addendum of teeth. Experiments show that the concaving and the plastic deflection are successfully reduced, the accuracy of tooth profile reaches to KS 0 class.

• Journal of the Korean Ceramic Society
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• v.55 no.2
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• pp.166-173
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• 2018

In order to investigate the effect of Mn on the dielectric and piezoelectric properties of PMN-PT [$Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$], four different types of 71PMN-29PT samples were prepared using the solid-state single crystal growth (SSCG) method: (1) Undoped single crystals, (2) undoped polycrystalline ceramics, (3) Mn-doped single crystals, and (4) Mn-doped polycrystalline ceramics. In the case of single crystals, the addition of 0.5 mol% Mn to PMN-PT decreased the dielectric constant ($K_3{^T}$), piezoelectric charge constant ($d_{33}$), and dielectric loss (tan ${\delta}$) by about 50%, but increased the coercive electric field ($E_C$) by 50% and the electromechanical quality factor ($Q_m$) by 500%, respectively. The addition of Mn to PMN-PT induced an internal bias electric field ($E_I$) and thus specimens changed from piezoelectrically soft-type to piezoelectrically hard-type. This Mn effect was more significant in single crystals than in ceramics. These results demonstrate that Mn-doped 71PMN-29PT single crystals, because they are piezoelectrically hard and simultaneously have high piezoelectric and electromechanical properties, have great potential for application in fields of SONAR transducers, high intensity focused ultrasound (HIFU), and ultrasonic motors.

• Korean Journal of Biological Psychiatry
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• v.11 no.1
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• pp.49-53
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• 2004

Objective:A Comparison of QTc prolongation for various antipsychotics and an analysis of QTc prolongation for the various types of serotonin transporter polymorphism were performed. Method:EKG was checked, followed by QTc measurement as Bazett's correction, and the serotonin transporter polymorphism was examined in 110 chronic schizophrenia patients were performed EKG before 24 weeks ago. We defiened QTc prolongation as over 450ms. The risk factor of sudden cardiac death were defiend as QTc prolongation and or 60ms in delta value. Result:The prevalence of QTc prolongation in this study was 7.3%, and the prevalence of over 60ms was 4.5%. Patients who had the risk factors were 10(9.1%). 6/52 who prescribed atypical antipsychotics and 2/58 who prescribed haloperidol showed QTc prolongation. The prevalence who had the risk factor of sudden cardiac death were 16% in atypical antipsychotics group, 3.4% in haloperidol group. QTc prolongation were observed more frequently in l/l type than s/s type. l allele frequency were 50% in QTc prolongated group, 19% in not prolongated group. l allele had an association with QTc prolongation(p<0.01). Conclusion:The prevalence of QTc prolongatin was frequent in chronic schizophrenia patients who were prescribed atypical antipsychotics. It has strong association with l allele of 5-HTTLPR.