• The Journal of Korean Obstetrics and Gynecology
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• v.24 no.1
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• pp.74-86
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• 2011

Objectives: The purpose of this study was to examine correlation between Heart Rate Variability and urine analysis of women with urinary disturbance. Methods: We studied 34 patients visiting ${\bigcirc}{\bigcirc}$hospital from January 2010 to September 2010. The subjects were categorized in two groups, symptom group (n=11) and no symptom group(n=23). We studied the difference of Heart Rate Variability and urine analysis between two groups by Student T-test and correlation between Heart Rate Variability and urine analysis by Pearson's correlation coefficient test using SPSS for windows (version 17.0). Results: Occult blood of symptom group was significantly higher than no symptom group. SDNN, TP and HF of symptom group was significantly lower than no symptom group. Occult blood and SDNN, occult blood and RMS-SD, occult blood and HF significantly showed negative correlation coefficient. pH and TP, pH and LF significantly showed positive correlation coefficient. Conclusion: The results suggest that urinary disturbance can be related to decreased activity of autonomic nervous system. Also urine from women with urinary disturbance tend to show higher occult blood.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.255-255
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• 2010

전하 트랩형 비휘발성 메모리는 10년 이상의 데이터 보존 능력과 빠른 쓰기/지우기 속도가 요구 된다. 그러나 두 가지 특성은 터널 산화막의 두께에 따라 서로 trade off 관계를 갖는다. 즉, 두 가지 특성을 모두 만족 시키면서 scaling down 하기는 매우 힘들다. 이것의 해결책으로 적층된 유전막을 터널 산화막으로 사용하여 쓰기/지우기 속도와 데이터 보존 특성을 만족하는 Tunnel Barrier engineered Memory (TBM)이 있다. TBM은 가운데 장벽은 높고 기판과 전극쪽의 장벽이 낮은 crested barrier type이 있으며, 이와 반대로 가운데 장벽은 낮고 기판과 전극쪽의 장벽이 높은 VARIOT barrier type이 있다. 일반적으로 유전율과 밴드갭(band gap)의 관계는 유전율이 클수록 밴드갭이 작은 특성을 갖는다. 이러한 관계로 인해 일반적으로 crested type의 터널 산화막층은 high-k/low-k/high-k의 물질로 적층되며, VARIOT type은 low-k/high-k/low-k의 물질로 적층된다. 이 형태는 밴드갭이 다른 물질을 적층했을 때 전계에 따라 터널 장벽의 변화가 민감하여 전자의 장벽 투과율이 매우 빠르게 변화하는 특징을 갖는다. 결국 전계에 민감도 향상으로 쓰기/지우기 속도가 향상되며 적층된 유전막의 물리적 두께의 증가로 인해 데이터 보존 특성 또한 향상되는 장점을 갖는다. 본 연구에서는 기존의 TBM과 다른 형태의 staggered tunnel barrier를 제안한다. staggered tunnel barrier는 heterostructure의 에너지 밴드 구조 중 하나로 밴드 line up은 두 밴드들이 같은 방향으로 shift된 형태이다. 즉, 가전자대 에너지 장벽의 minimum이 한 쪽에 생기면 전도대 에너지 장벽의 maximum은 반대쪽에 생기는 형태를 갖는다. 이러한 밴드구조를 갖는 물질을 터널 산화막층으로 하게 되면 쓰기/지우기 속도를 증가시킬 수 있으며, 데이터 보존 능력 모두 만족할 수 있어 TBM의 터널 산화막으로의 사용이 기대된다. 본 연구에서 제작한 staggered TBM소자의 터널 산화막으로는 $Si_3N_4$/HfAlO (Hf:Al=1:3)을 사용하여 I-V(current-voltage), Retention, Endurance를 측정하여 메모리 소자로서의 특성을 분석하였으며, 터널 산화막의 제 1층인 $Si_3N_4$의 두께를 1.5 nm, 3 nm일 때의 특성을 비교 분석하였다.

• Nutrition Research and Practice
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• v.10 no.1
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• pp.42-48
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• 2016

BACKGROUND/OBJECTIVES: Seaweeds have been reported to have various health beneficial effects. In this study, we investigated the potential anti-obesity and anti-inflammatory effects of four types of domestic brown seaweeds in a high-fat diet-induced obese mouse model and bone marrow-derived macrophages (BMDM). MATERIALS/METHODS: Male C57BL/6N mice were fed low-fat diet (LFD), high-fat diet (HFD) or HFD containing Undaria Pinnatifida, HFD containing Laminaria Japonica (LJ), HFD containing Sargassum Fulvellum, or HFD containing Hizikia Fusiforme (HF) for 16 weeks. RESULTS: Brown seaweed supplementation did not affect long-term HFD-associated changes in body weight or adiposity, although mice fed HFD + LJ or HFD + HF gained slightly less body weight compared with those fed HFD at the beginning of feeding. Despite being obese, mice fed HFD + LJ appeared to show improved insulin sensitivity compared to mice fed HFD. Consistently, we observed significantly reduced blood glucose concentrations in mice fed HFD + LJ compared with those of mice fed HFD. Although no significant differences in adipocyte size were detected among the HFD-fed groups, consumption of seaweeds decreased formation of HFD-induced crown-like structures in gonadal adipose tissue as well as plasma inflammatory cytokines. BMDM from mice fed HFDs with seaweeds showed differential regulation of pro-inflammatory cytokines such as IL-$1{\beta}$ and IL-6 compared with BMDM from mice fed HFD by LPS stimulation. CONCLUSION: Although seaweed consumption did not prevent long-term HFD-induced obesity in C57BL/6N mice, it reduced insulin resistance (IR) and circulation of pro-inflammatory cytokines. Therefore, seaweeds may ameliorate systemic inflammation and IR in obesity partially due to inhibition of inflammatory signaling in adipose tissue cells as well as bone marrow-derived immune cells.

• Restorative Dentistry and Endodontics
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• v.44 no.3
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• pp.31.1-31.9
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• 2019

Objectives: To compare the formation of dentinal defects using stainless-steel hand K-files (HFs), rotary files, reciprocating files, and Self-Adjusting File (SAF), when used for oval root canals. Materials and Methods: One hundred and forty extracted human mandibular premolar with single root and oval canal were selected for this study. Oval canals were confirmed by exposing to mesio-distal and bucco-lingual radiographs. Teeth with open apices or anatomic irregularities were excluded. All selected teeth were de-coronated perpendicular to the long axis of the tooth, leaving roots segments approximately of 16 mm in length. Twenty teeth were left unprepared (control), and the remaining 120 teeth were divided into 6 groups (n = 20) and instrumented using HF (size 40/0.02), Revo-S (RS; size 40/0.06), ProTaper NEXT (PTN; size 40/0.06), WaveOne (WO; size 40/0.09), RECIPROC (RC; size 40/0.06), and the SAF (2 mm). Roots were then sectioned 3, 6, and 9 mm from the apex, and observed under stereomicroscope, for presence of dentinal defects. "No defect" was defined as root dentin that presented with no visible microcracks or fractures. "Defect" was defined by microcracks or fractures in the root dentin. Results: The control, HF, and SAF did not exhibit any dentinal defects. In roots instrumented by RS, PTN, WO, and RC files exhibited microcracks (incomplete or complete) in 40%, 30%, 55%, and 50%, respectively. Conclusions: The motor-driven root canal instrumentation with rotary and reciprocating files may create microcracks in radicular dentine, whereas the stainless-steel hand file instrumentation, and the SAF produce minimal or less cracks.

• Journal of Korean Biological Nursing Science
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• v.23 no.1
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• pp.22-30
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• 2021

Purpose: This descriptive study aimed to investigate heart rate variability (HRV) according to sex and to elucidate the influence of negative emotion such as levels of stress, anxiety and depression on HRV among Korean college students based on a neurovisceral integration model. Methods: A descriptive study design was used. Eighty-six healthy college students participated in the study. Resting HRV and standing HRV on orthostatic stimulation were measured for 5 minutes during 4-6 p.m. in the afternoon. Levels of stress, anxiety and depression were assessed using the Global assessment of recent stress, State-Trait Anxiety Inventory and Beck Depression Index, respectively. Results: Out of the 86 students, 47 (54.7%) were men and 39 (45.3%) were women. Root mean square of the differences between adjacent RR intervals (RMSSD) and normalized high frequency (nHF) on standing HRV were significantly lower in men than in women (p= .005, p= .019, respectively). Male gender (β= 0.30, p= .013), higher level of stress (β= -0.36, p= .009) and lower level of depression (β = 0.30, p= .044) exerted a significant influence on decreased nHF in the multiple regression analysis. Conclusion: We suggest that men are more vulnerable to having reduced vagal activity on HRV than women. Since male gender, higher level of stress and lower level of depression level influenced decreased vagal activity, strategies are needed to improve stress and depression rather than anxiety especially for men, which contribute to promoting HRV to prevent cardiac health diseases.

• Journal of Surface Science and Engineering
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• v.41 no.5
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• pp.189-193
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• 2008

In this study, we carried out an investigation of the etching characteristics (etch rate, selectivity to $SiO_2$ and $HfO_2$) of TiN thin films in the $CH_4$/Ar inductively coupled plasma. The maximum etch rate of $274\;{\AA}/min$ for TiN thin films was obtained at $CH_4$(80%)/Ar(20%) gas mixing ratio. At the same time, the etch rate was measured as function of the etching parameters such as RF power, Bias power, and process pressure. The X-ray photoelectron spectroscopy analysis showed an efficient destruction of the oxide bonds by the ion bombardment as well as showed an accumulation of low volatile reaction products on the etched surface. Based on these data, the ion-assisted chemical reaction was proposed as the main etch mechanism for the $CH_4$ containing plasmas.

• Bulletin of the Korean Chemical Society
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• v.23 no.2
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• pp.241-244
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• 2002

Using ab initio method, we have studied the structural stabilities, the electronic structures and properties between the two isomers with $C_{2h}$ and $C_{2v}$ symmetry of AlN four-membered-ring single precursors $[Me_2AlNHR]_2$ (R = Me, $^iPr$, and $^iBu$). In the viewpoint of bond lengths in optimized structures, the N-C bonds are considerably affected by the change of the R groups bonded to nitrogen, but the bonding characters of the Al-N and Al-C bonds are little affected. Also the structural stabilities between the two isomers with $C_{2h}$ and $C_{2v}$ symmetry by using Hartree-Fock (HF) and the second order Moeller-Pleset (MP2) calculations agree well with the experimental results for the relative stability of bis(dimethyl- m-isopropylamido-aluminum) (BDPA) and bis(dimethyl- m-t-butylamido-aluminum) (BDBA), while the semiempirical AM1 and PM3 calculations for BDPA were reverse. Thus, our results may aid in designing an optimum precursor for a given process by explaining the experimental results through the elimination of the R groups bonded to nitrogen.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.26.1-26.1
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• 2011

We investigated the atomic layer deposition (ALD) process for nitrogen doped ZnO and the application for n-ZnO : N/p-Si (NW) coaxial hetero-junction photodetectors. ALD ZnO:N was deposited using diethylzinc (DEZ) and diluted $NH_4OH$ at $150^{\circ}C$ of substrate temperature. About 100~300 nm diameter and 5 um length of Si nanowires array were prepared using electroless etching technique in 0.108 g of $AgNO_3$ melted 20 ml HF liquid at $75^{\circ}C$. TEM images showed ZnO were deposited on densely packed SiNW structure achieving extraordinary conformality. When UV (360 nm) light was illuminated on n-ZnO:N/p-SiNW, I-V curve showed about three times larger photocurrent generation than film structure at 10 V reverse bias. Especially, at 660 nm wave length, the coaxial structure has 90.8% of external quantum efficiency (EQE) and 0.573 A/W of responsivity.

• Bulletin of the Korean Chemical Society
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• v.20 no.9
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• pp.1067-1072
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• 1999

Structures of unprotonated [(NH3)n+(n = 1-6)] and protonated [NH4+(NH3)n-1(n = 1-6)] ammonia cluster cations have been optimized with ab initio Hartree-Fock (HF) and second-order MФller-Plesset (MP2)/6-31+G ** levels and the harmonic vibrational frequencies have also been evaluated. In unprotonated cluster cations, NH3+ forms as a central core of the first ammonia solvation shell. In protonated cluster cations, NH4+ forms as a central core. In unprotonated dimer and trimer cations, there are two types of isomers (hydrogen-bonded and head-to-head interactions). In both cluster cations, the hydrogen-bonded isomers are more stable. In the hydrogen-bonded dimer cation, the proton transfer reaction takes place from (NH3-HN+H2) to (NH4+-NH2). But in the other unprotonated cluster cations, the proton transfer does not take place. In unprotonated pentamer and hexamer, a NH3+ core has both interactions in a complex. On the other hand, in unprotonated tetramer a core has only the hydrogen-bonded type combined with neutral ammonia molecules. With increasing cluster cation size, the bond lengths [R(NN)] between two nitrogen atoms and the distances [R(N ...H)] of the hydrogen-bond increase reg-ularly. In the calculated infra-red absorption bands for ammonia cluster cations, the characteristic peaks of the bridged NH vibration of the hydrogen-bonded clusters appear near 2500 cm-1 . With increasing size, the peaks shift from 2306 cm-1 to 2780 cm-1 .

• Journal of Surface Science and Engineering
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• v.52 no.2
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• pp.53-57
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• 2019

Stability and activity of boron doped diamond (BDD) electrode are key factors for water treatment. In this study, BDD electrodes were prepared on various substrates such as Nb, Si, Ti, and $TiN_x/Ti$ by hot filament chemical vapor deposition (HFCVD) method. BDD/Ti film showed the delamination between BDD and Ti substrate due to the formation of TiC layer caused by diffusion of carbon. On the other hand, $BDD/TiN_x/Ti$ showed remarkably improved stability, compared to BDD/Ti. It was confirmed that $TiN_x$ intermediate layer act as barrier layer for diffusion of carbon. High potential window of 2.8 eV was maintained on the $BDD/TiN_x/Ti$ electrode and, better wastewater treatment capability and longer electrode working life than BDD/Nb, BDD/Si and BDD/Ti were obtained.