• Restorative Dentistry and Endodontics
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• v.45 no.3
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• pp.33.1-33.10
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• 2020

Objectives: This study was conducted to evaluate the effects of traditional and contracted endodontic cavity (TEC and CEC) preparation with the use of Reciproc Blue (RPC B) and One Curve (OC) single-file systems on the amount of apical debris extrusion in mandibular first molar root canals. Materials and Methods: Eighty extracted mandibular first molar teeth were randomly assigned to 4 groups (n = 20) according to the endodontic access cavity shape and the single file system used for root canal preparation (reciprocating motion with the RCP B and rotary motion with the OC): TEC-RPC B, TEC-OC, CEC-RPC B, and CEC-OC. The apically extruded debris during preparation was collected in Eppendorf tubes. The amount of extruded debris was quantified by subtracting the weight of the empty tubes from the weight of the Eppendorf tubes containing the debris. Data were analyzed using 1-way analysis of variance with the Tukey post hoc test. The level of significance was set at p < 0.05. Results: The CEC-RPC B group showed more apical debris extrusion than the TEC-OC and CEC-OC groups (p < 0.05). There were no statistically significant differences in the amount of apical debris extrusion among the TEC-OC, CEC-OC, and TEC-RPC B groups. Conclusions: RPC B caused more apical debris extrusion in the CEC groups than did the OC single-file system. Therefore, it is suggested that the RPC B file should be used carefully in teeth with a CEC.

• Food Science of Animal Resources
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• v.32 no.2
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• pp.234-240
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• 2012

This study was conducted to examine the effects of low molecular weight gelatin hydrolysates (GH, less than 3kDa), extracted from pig skin collagen on the bone metabolism of ovariectomized (OVX) rats. The rats in the experimental groups were randomly segregated into six different treatment groups such as 1) NC, the normal rat fed AIN 93 diet (basal diet) only; 2) OC, the OVX rat fed the basal diet only; 3) GH 0.1, the OVX rat fed the basal diet with 0.1% GH; 4) GH 0.8, the OVX rat fed the basal diet with 0.8% GH; 5) G 0.1, the OVX rat fed the basal diet with 0.1% gelatin; 6) G 0.8, the OVX rat fed the basal diet with 0.8% gelatin. Body weight gain in the GH 0.1, GH 0.8, and G 0.8 was significantly higher than those in the NC and OC. Feed intake of the GH 0.1 and GH 0.8 was higher than that of the NC and OC, while no significant difference was found in feed efficiency ratio (FER). BMD of the GH 0.8 was higher than that of the OC. However, gelatin hydrolysates and gelatin resulted in higher BMC level compare to the OC. Serum HDL-cholesterol of rat fed GH and gelatin was higher than that of OC (p<0.05). LDL-C of the GH 0.1 and the GH 0.8 tended to be less than that of OC. Serum alkaline phosphatase (ALP) of the GH 0.1 was lower than that of the OC. The serum of GH 0.8 showed lower osteocalcin value than the OC (p<0.05). In addition, GOT and GPT levels significantly decreased in all treatment groups. These results indicated that gelatin hydrolysates from pig skin gelatin hydrolysates enhanced BMD and serum biochemical parameters related to bone metabolism. Therefore, the gelatin hydrolysates could be used as a beneficial material to improve bone health.

• Journal of Industrial Convergence
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• v.7 no.1
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• pp.83-100
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• 2009

The purpose of this study was to investigate the influence of Perceived Organizational Support(POS) and on Organizational Citizenship Behavior through Organizational Commitment(OC). In order to attain the objectives of this study, a model was established and hypothesis was verified on the basis of preceding studies. In a model proposed for this study, POS was used as antecedents to OC while OCB was used as consequences for OC. The sample included 387 employees. Structural equation modeling(SEM) was used to employed the hypothesized relationships in the conceptual model. Results indicated that (a)POS has a positive impact OC; (b)affective OC has a positive impact OCB; (c)continuance OC has a negative(or zero) impact QCB. Implications are discussed and future research directions are outlined.

• Journal of the Semiconductor & Display Technology
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• v.17 no.2
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• pp.32-35
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• 2018

The current voltage characteristics of ZTO/SiOC were researched, and the conductivities of the ZTO films as a channel material were analyzed. The current of SiOC was abruptly decreased near 0V, and then the depletion layer was formed by the disappearance of charges in the region form -12V to +12V. SiOC with Schottky contacts near ${\sim}10^{-9}$ A had the cutoff effect of leakage currents. The conductivity of ZTOs prepared on SiOC was improved in the cutoff region of the leakage current of -12V

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.1
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• pp.28-40
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• 2015

To investigate the seasonal variations of carbonaceous aerosol in Daejeon, OC (organic carbon), EC (elemental carbon) and WSOC (water soluble organic carbon) in $PM_{2.5}$ samples collected from March 2012 to February 2013 were analyzed. $PM_{2.5}$ concentrations were estimated by the sum of organic matter ($1.6{\times}OC$), EC, water-soluble ions ($Na^+$, $NH_4{^{+}}$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, $SO_4{^{2-}}$, $NO_3{^{-}}$). The estimated $PM_{2.5}$ concentrations were relatively higher in winter ($29.50{\pm}12.04{\mu}g/m^3$) than those in summer ($13.72{\pm}6.92{\mu}g/m^3$). Carbonaceous aerosol ($1.6{\times}OC+EC$) was a significant portion (34~47%) of $PM_{2.5}$ in all season. The seasonally averaged OC and WSOC concentrations were relatively higher in winter ($6.57{\times}3.48{\mu}gC/m^3$ and $4.07{\pm}2.53{\mu}gC/m^3$ respectively), than those in summer ($3.07{\pm}0.8{\mu}gC/m^3$, $1.77{\pm}0.68{\mu}gC/m^3$, respectively). OC was correlated well with WSOC in all season, indicating that they have similar emission sources or formation processes. In summer, both OC and WSOC were weakly correlated with EC and also poorly correlated with a well-known biomass burning tracer, levoglucosan, while WSOC is highly correlated with SOC (secondary organic carbon) and $O_3$. The results suggest that carbonaceous aerosol in summer was highly influenced by secondary formation rather than primary emissions. In contrast, both OC and WSOC in winter were strongly correlated with EC and levoglucosan, indicating that carbonaceous aerosol in winter was closely related to primary source such as biomass burning. The contribution of biomass burning to $PM_{2.5}$ OC and EC, which was estimated using the levoglucosan to OC and EC ratios of potential biomass burning sources, was about $70{\pm}15%$ and $31{\pm}10%$, respectively, in winter. Results from this study clearly show that $PM_{2.5}$ OC has seasonally different chemical characteristics and origins.

• The Korean Journal of Physiology
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• v.25 no.1
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• pp.61-67
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• 1991

In order to determine possible relationships between the renin-angiotensin system and nephron heterogeneity, we compared the response of renin release and the angiotensin-converting enzyme (ACE) activity from different areas of the rat kidney. We used the renal cortical slices from the capsular surface to the juxtamedullary junction. Slices from outer one-third of the cortex were designated as outer cortical slices (OC), middle one-third as midcortical slices (MC), and inner one-third as inner cortical slices (IC). The renal renin content markedly decreased from OC and MC to IC. The basal lenin release was higher in OC than in MC or IC. On the contrary the percent change of renin release in response to L-isoproterenol was significantly higher in MC than in OC or IC. By TMB-8, the renin release in MC by $231{\pm}21%$ was higher than OC by $171{\pm}19%$ or IC by $$162{\pm}19. Angiotensin II suppressed renin release in OC and MC by $68{\pm}2,\;71{\pm}4%$ respectively, but only $40{\pm}7%$ in IC. The ACE activity was higher in IC than in OC, MC, medulla and papilla. The present data indicate that renin content and basal lenin release gradulally decreased from outer (OC) to inner (IC) cortex. The renin release in response to beta-adrenergic agonist, L-isoproterenol and intracellular calcium antagonist, TMB-8 were higher in MC than in OC and IC, but angiotensin II suppressed renin release less in IC than in OC and MC. It is suggested that juxtaglomerular cells of outer, mid-and inner cortices show a difference in renin release response to the stimuli.

• Korean Journal of Materials Research
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• v.21 no.1
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• pp.8-14
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• 2011

To improve the chemical stability of metal, the ceramic coatings on metallic materials have attracted interest from many researchers due to the chemical inertness of ceramic materials. To endure strong acids, SiOC coating on metal substrate was carried out by dip coating method using 20wt% polyphenylcarbosilane solution; SiC powder was added to the solution at 10wt% and 15wt% to improve the mechanical properties and to prevent cracks of the film. Thermal oxidation as a curing step was carried out at $200^{\circ}C$ for crosslinking of the polyphenylcarbosilane, and the coating samples were pyrolysized at $800^{\circ}C$ under argon to convert the polyphenylcarbosilane to SiOC film. The thicknesses of the SiOC coating films were $2.36{\mu}m$ and $3.16{\mu}m$. The quantities of each element were measured as $SiO_{1.07}C_{6.33}$ by EPMA, and it can be confirmed that the SiOC film from polyphenylcarbosilane was formed in a manner that was carbon rich. The hardness of the SiOC film was found to be 3.2Gpa through nanoindentor measurement. No defect including cracks appeared in the SiOC film. The weight loss of the SiOC coated stainless steel was within 2% after soaking in 10% HCl solution at $80^{\circ}C$ for one week. From these results, SiOC coating shows good potential for application to protect against severe chemical corrosion of stainless steel.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.1
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• pp.131-140
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• 2005

To investigate secondary carbonaceous species within PM$_{10}$ and PM$_{2.5}$ in Seoul urban Metropolitan Area (SMA), Korea. atmospheric particulate matters samples were collected at two sites of SMA at UOS (The University Of Seoul station) sites and IHU (InHa University of Incheon station) during the period of 4 to 14 January and 12 to 22 May, 11 to 15 August 2004, and their characteristics were qualitatively discussed. during January and May and August of 2004. Daily average mass concentration 0.095 mg/㎥ in PM$_{10}$ and 0.053 mg/㎥ in PM$_{2.5}$ for mass respectively. were observed in SMA. The concentrations of carbonaceous species contributed 18.4% and 16.4% of PM$_{2.5}$ and PM$_{10}$ during the sampling period, respectively, of which OC accounted for 68% and 52% more of the total carbon (TC). OC and EC concentrations and their mass percentages were higher in PM$_{2.5}$ than in PM$_{10}$ which could be attributed to generation process. Organic aerosols would constitute up to 38% of PM$_{2.5}$ based on the evaluation of 1.6 for the ratio of OC to organic particulate. Secondary organic carbon (SOC) were estimated to be more than 13% and up to 68% of total OC based on the minimum OC/EC ratio of 1.06/1.11 using least square method. Comparisons of OC and EC with trace elements. As results of carbonaceous species analysis, the dominant factor in view of fine particle (PM$_{10}$/PM$_{2.5}$) is primary emission source such as mobile, fossil fuel combustion etc. during winter time in SMA. But in summer periods, remarkable fine particle increasing factor was secondary organic carbon dependent to photochemical reaction. reaction.n. reaction.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.94.1-94.1
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• 2012

폴리페닐카보실란은 페닐그룹을 포함하고 있는 카보실란계 고분자로서 열분해 후 과량의 탄소를 함유할 수 있는 세라믹 전구체이다. 카보실란계열의 고분자는 산화특성이 있어 SiOC 코팅 용도에도 사용되고 있는데, 폴리페닐카보실란은 free 탄소를 함유하는 SiOC:C 필름을 형성할 수 있다. SiOC 코팅 전구체로는 일반적으로 실리카졸, 실라잔 계열의 고분자, 실록산 계열의 고분자가 사용되고 있으나, 폴리페닐카보실란의 경우 상기 전구체에 비하여 보관 안정성 및 뛰어난 부착특성을 나타낸다. 기존 연구에서는 폴리페닐카보실란으로부터 형성된 SiOC:C 필름의 저유전막, 산화방지막, 분진방지막 등의 응용성에 대하여 고찰한 바 있다. 폴리페닐카보실란은 열처리 온도 영역에 따라 응용 분야가 달라질 수 있는데, 이에 본 연구에서는 각 열처리 온도 영역에 따라 형성되는 SiOC:C 필름의 구조적 변화를 고찰하였다. 필름 형성은 20 % 폴리카보실란 용액을 스핀코팅하고 대기상에서 경화를 실시하였으며, 질소 분위기에서 400 ~ 1200 도 범위에서 열처리하였다. 이렇게 얻어진 300 nm 두께의 필름은 XPS 표면분석과 FT-IR, Solid-NMR을 이용하여 C-Si-O 네트워크 형성의 거동을 확인하였으며, 800 도 이상에서 나타나는 특징적인 free 탄소는 Raman을 이용하여 확인하였다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.2
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• pp.195-200
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• 2013

This study investigated the effects of water temperature, photoperiod and population density on oxygen consumption (OC) in the longtooth grouper (Epinephelus bruneus). OC rate in the longtooth grouper at 15, 20, and $25^{\circ}C$ were $85.9{\pm}6.9$, $107.5{\pm}10.1$, and $164.0{\pm}19.2\;mg\;O_2\;kg^{-1}\;h^{-1}$, respectively, indicating a linear increase in OC with water temperature. Photoperiod was regulated in accordance with the light (09:00-21:00 h, L) and dark (21:00-09:00 h, D) phases of the diel cycle (12L/12D), with a water temperature of 15, 20, or $25^{\circ}C$. OC rates during the light and dark phases were $83.8{\pm}5.4$, $88.1{\pm}7.8\;mg\;O_2\;kg^{-1}\;h^{-1}$, respectively, at $15^{\circ}C$ and $111.2{\pm}12.3$ and $103.7{\pm}5.7\;mg\;O_2\;kg^{-1}\;h^{-1}$ at $20^{\circ}C$. No significant differences were observed between the light and dark phases (P > 0.05). at $25^{\circ}C$ the OC rates were $168.8{\pm}24.3$ and $159.2{\pm}11.4\;mg\;O_2\;kg^{-1}\;h^{-1}$ during the light and dark phases, respectively, indicating that OC is higher during daylight than nighttime. OC tates at 55.4, 88.4, 118.8, and 145.1 g $L^{-1}$ were $252.0{\pm}11.6$, $219.0{\pm}8.7$, $206.7{\pm}11.4$, and $208.8{\pm}11.4\;mg\;O_2\;kg^{-1}\;h^{-1}$, respectively, indicating a decrease in OC with increasing population density. However, no significant difference was observed between the values for 118.8 g $L^{-1}$ and 145.1 g $L^{-1}$ (P > 0.05).