A Case of Urethral Stent for Recurrent Urethral Stricture and Penile Prosthesis for Erectile Dysfunction

Jung, Gyung-Woo,Song, Young-Jin,Park, Young-Ho,Kwon, Heon-Young,Yoon, Jin-Han 동아대학교의과대학 1992 동아의대학술지 Vol.4 No.1

AN IN-SITU YOUNG'S MODULUS MEASUREMENT TECHNIQUE FOR NUCLEAR POWER PLANTS USING TIME-FREQUENCY ANALYSIS

Choi, Young-Chul,Yoon, Doo-Byung,Park, Jin-Ho,Kwon, Hyun-Sang Korean Nuclear Society 2009 Nuclear Engineering and Technology Vol.41 No.3

Elastic wave is one of the most useful tools for non-destructive tests in nuclear power plants. Since the elastic properties are indispensable for analyzing the behaviors of elastic waves, they should be predetermined within an acceptable accuracy. Nuclear power plants are exposed to harsh environmental conditions and hence the structures are degraded. It means that the Young's modulus becomes unreliable and in-situ measurement of Young's modulus is required from an engineering point of view. Young's modulus is estimated from the group velocity of propagating waves. Because the flexural wave of a plate is inherently dispersive, the group velocity is not clearly evaluated in temporal signal analysis. In order to overcome such ambiguity in estimation of group velocity, Wigner-Ville distribution as the time-frequency analysis technique was proposed and utilized. To verify the proposed method, experiments for steel and acryl plates were performed with accelerometers. The results show good estimation of the Young's modulus of two plates.

Polystyrene composites containing crosslinked polystyrene-multiwalled carbon nanotube balls

Kwon, Soon-Min,Kim, Hun-Sik,Kim, Don-Young,Yun, Young Soo,Jin, Hyoung-Joon Wiley Subscription Services, Inc., A Wiley Company 2008 Journal of applied polymer science Vol.110 No.6

<P>Crosslinked polystyrene-multiwalled carbon nanotube (PS-MWCNT) balls, which act as conductive microfillers, were prepared by the in situ suspension polymerization of styrene with MWCNTs and divinyl benzene (DVB) as a crosslinking agent. The diameters of the synthesized crosslinked PS-MWCNT balls ranged from 10 to 100 μm and their electrical conductivity was about 7.7 × 10<SUP>−3</SUP> S/cm. The morphology of the crosslinked PS-MWCNT balls was observed by scanning electron microscopy and transmission electron microscopy. The change in the chemical structure of the MWCNTs was confirmed by Raman spectroscopy and Fourier transform infrared spectroscopy. The mechanical and electrical properties of the PS/crosslinked PS-MWCNT ball composites were investigated. It was found that the tensile strength, ultimate strain, Young's modulus, and impact strength of the PS matrix were enhanced by the incorporation of the crosslinked PS-MWCNT balls. In addition, the mechanical properties of the PS/crosslinked PS-MWCNT ball composites were better than those of the PS/pristine MWCNT composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008</P>

Male preference for TERT alterations and HBV integration in young-age HBV-related HCC: implications for sex disparity

Jin Seoub Kim,Hye Seon Kim,Kwon Yong Tak,Ji Won Han,Heechul Nam,Pil Soo Sung,Sung Won Lee,Jung Hyun Kwon,Si Hyun Bae,Jong Young Choi,Seung Kew Yoon,Jeong Won Jang 대한간학회 2025 Clinical and Molecular Hepatology(대한간학회지) Vol.31 No.2

Background/Aims: Hepatocellular carcinoma (HCC) exhibits significant sex disparities in incidence, yet its molecular mechanisms remain unclear. We explored the role of telomerase reverse transcriptase (TERT) genetic alterations and hepatitis B virus (HBV) integration, both known major contributors to HCC, in sex-specific risk for HBV-related HCC. Methods: We examined 310 HBV-related HCC tissues to investigate sex-specific TERT promoter (TERT-pro) mutations and HBV integration profiles, stratified by sex and age, and validated with single-cell RNA sequencing (scRNA-seq) data. Results: Tumors predominantly exhibited TERT-pro mutations (26.0% vs. 0%) and HBV-TERT integration (37.0% vs. 3.0%) compared to non-tumorous tissues. While TERT-pro mutations increased with age in both sexes, younger males (≤60 years) showed marked predominance compared to younger females. Males had significantly more HBV integrations at younger ages, while females initially had fewer integrations that gradually increased with age. Younger males' integrations showed significantly greater enrichment in the TERT locus compared to younger females, alongside a preference for promoters, PreS/S regions, and CpG islands. Overall, TERT genetic alterations were significantly sex-differential in younger individuals (75.3% in males vs. 23.1% in females) but not in older individuals (76.9% vs. 83.3%, respectively). These alterations were associated with increased TERT expression. The skewed TERT abnormalities in younger males were further corroborated by independent scRNA-seq data. Conclusions: Our findings highlight the critical role of TERT alterations and HBV integration patterns in the male predominance of HCC incidence among younger HBV carriers, offering insights for future exploration to optimize sex-specific patient care and HCC surveillance strategies.

GASKET LIFE CRITERIA AT LOW TEMPERATURES ADOPTING PROPORTIONAL COMPENSATION FOR LOSS OF FLEXIBILITY AND CONFORMABILITY

Young-Doo Kwon,Seong-Hwa Jun,Jin-Sik Han,Dong-Jin Lee 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.1

In the automobile industry, the service life of gaskets is defined as the time until which a released gasket recovers 60 % of the original compression. It was observed that the recovery curves of gaskets were highly nonlinear at high temperatures, and relatively nonlinear at temperatures above the room temperature. However, it was also noted that the recovery curves of the gaskets at temperatures below room temperature exhibited linearity with respect to the ln(time). Automotive manufacturers demand gasket life criteria that exceed a specific time or the entire life of a car. In the case of gaskets used at lower temperatures, since materials encounter losses in its flexibility and conformability, the definition of service life specifying a 60 % recovery may not be sufficiently safe to eliminate possible leakages. In this study, new gasket life criteria that could be used at low temperatures were proposed. The new criteria were proposed based on the change in Young’s modulus of the gasket material in order to conserve the sealing capability.

소규모 하수처리를 위한 파일럿 규모 이중슬러지 KNR<SUP>Ⓡ</SUP>(Kwon's nutrient removal)시스템의 영얌염류 제거성능 평가

안진영(Jin-Young An),권중천(Joong-Chun Kwon),김윤학(Yun-Hak Kim),정유훈(Yoo-Hoon Jeng),김두언(Doo-Eon Kim),유선호(Sun-Ho Ryu),김병우(Byung-Woo Kim) 한국청정기술학회 2006 청정기술 Vol.12 No.2

산업집중도와 기업설명회 개최 간의 관련성 연구

권오진(Kwon Oh-jin),여영준(Yeo Young-jun) 한국국제회계학회 2017 국제회계연구 Vol.0 No.71

본 연구는 산업집중도와 기업의 대표적인 자발적 공시 수단인 기업설명회 개최 간의 관계를 살펴봄으로써, 산업집중도에 따라 전유정보 공시비용이 달라지며 이로 인하여 경영자의 자발적인 공시정책에 차이가 존재하는 지를 실증적으로 검증해보고자 한다. 공시는 기업과 투자자 간의 정보비대칭을 낮춤으로써, 기업의 자본비용 감소 및 가치증가와 같은 경제적인 효익이 존재함에도 불구하고 현실적으로는 완전한 공시가 이루어지지 못하고 있다. 선행연구들은 전유정보 공시비용의 존재가 기업의 완전공시를 저해하며, 이로 인해 경영자들은 공시로 인한 효익과 비용을 고려하여 기업가치를 극대화하는 방향으로 공시를 수행하게 된다는 것을 주장하였다(Verrecchia 1983). 또한 산업의 집중도에 따라 전유정보공시비용이 차이가 존재함을 보고하였다(Harris 1998; Botosan and Standford 2005; Verrecchia and Weber 2006; Li 2010; Ali et al. 2014). 이에 따라 본 연구는 우리나라 기업들을 대상으로 자발적 공시의 대표적인 수단인 기업설명회를 사용하여, 산업집중도와 자발적 공시 간의 관계를 분석해보고자 한다. 산업집중도와 기업설명회 개최 간에는 양방향의 예측이 가능하다. 먼저, 집중도가 낮은 산업에 속한 기업이 사적정보를 공시할 경우, 산업 내 다른 경쟁기업들이 이러한 정보를 이용하여 공격적으로 대응할 수 있어, 공시기업은 경쟁지위를 위협받을 더 높은 가능성에 직면된다. 특히, 기업설명회는 기업에 대한 포괄적인 정보를 제공하므로, 이러한 정보가 시장에 제공된다면 경쟁기업들은 좀 더 전략적으로 대응할 수 있게 될 것이다. 이에 따라 산업집중도가 낮을수록 경영자의 자발적 공시는 감소될 수 있다. 다른 한편으로, 산업집중도가 높을수록 기업들은 일반적으로 높은 수익성을 가지게 되는데, 경영자들은 이러한 높은 수익성을 감추기 위해 자발적으로 정보를 제공하는 것을 기피할 수 있다. 실증분석 결과 산업집중도와 기업설명회 개최 여부 및 개최 횟수 간에는 양(+)의 관련성을 가지는 것을 확인할 수 있다. 이는 집중도가 낮은 산업에 속한 기업일수록 전유정보 공시비용이 증가하므로, 경영자가 공시의 효익 보다 비용이 더 클 것으로 판단하여 공시를 기피한다는 것으로 해석할수 있다. This paper examines the relation between industry concentration and Investor Relations(hereafter, IR) activities. Prior literatures report that corporate disclosure reduces firms’ cost of capital(Barry and Brown 1984, 1985; Botosan 1997; Sengupta 1998; Botosan and Plumlee 2002) and increases stock liquidity(Diamond and Verrecchia 1991; Healy et al. 1999; Leuz and Verrecchia 2000) by decreasing the information asymmetry between manager and outside investors. Despite these benefits of corporate disclosure, managers do not release the full information of firms. According to prior studies, the existence of proprietary cost gives an incentive to the manager exercising discretion in disclosing information(Verrecchia 1983; Healy and Palepu 2001; Beyer 2010). Proprietary cost is the cost related to disclosing information which is potentially damaging to a firm. Prior studies also report that proprietary cost varies according to industry concentration. For this reason, this study expect that managers will provide the information of firms to the public when they think that the benefits of disclosure are greater than the costs of disclosure to maximize their firm value. We expect that industry concentration is positively associated with IR activities. Because competitors are likely to take more strategic behaviors in response to its disclosure when a firm in a less concentrated industry provides its information to the public. As a result, competitors’ strategic behaviors have a harmful impact on a firm’s competitive position(Verrecchia 1983; Wagenhofer 1990; Clinch and Verrecchia 1997; Verrecchia and Weber 2006; Dedman and Lennox 2009). In contrast, a firm in a more concentrated industry may see no costs related to making public disclosure. In particular, IR disclosure provides more comprehensive informations of companies, and capital market participants are available to obtain IR information easily, because managers are required to report the time, place and contents of IR activities to Korea Investor’s Network for Disclosure System(hereafter, KIND) prior to the firm holding IR. On the other hand, the firm in more concentrated industries are less likely to provide IR disclosure. In general, highly concentrated industries are characterized by consisting of only a small number of companies, wherein these companies will have a high profitability. If a firm in more concentrated industry releases information about highly abnormal profits, it could attract more entrants into the industry to compete for market share. For this reason, a firm in more concentrated industry provides less IR disclosure to protect their abnormal profits and large market share(Harris 1998; Botosan and Stanford 2005; Kim 2012). Taken together, the association between industry concentration and IR activities is capable of bidirectional prediction. To perform our hypothesis, we collect financial data from TS-2000 and ex stock and analyst data from Fn-Guide. In addition, IR data are collected by hand from KIND. As a result, we use 7,017 firmyear observations listed on KOSPI from 2002 to 2014 period. To measure the level of industry concentration which is independent variable, this paper uses Hirschman-Herfindahl Index(hereafter, HHI) and three-firm concentration ratio(hereafter, CR3) which are the most commonly used proxies for the degree of industry concentration. The level of IR activities which is dependent variable is measured as the frequency of IR activities, and whether or not a firm is engaged in IR activities. The empirical findings of this study are as follows. We find that industry concentration is positively associated with IR activities. In other words a manager whose firm operates in a less concentrated industry is less likely to provide information about companies to the public, because the proprietary cost is higher than the benefit of disclosure when industry concentration is relatively low.

소규모 하수처리를 위한 파일럿 규모 이중슬러지 KNR^® (Kwon's nutrient removal) 시스템의 영얌염류 제거성능 평가

안진영,권중천,김윤학,정유훈,김두언,유선호,김병우,An, Jin-Young,Kwon, Joong-Chun,Kim, Yun-Hak,Jeng, Yoo-Hoon,Kim, Doo-Eon,Ryu, Sun-Ho,Kim, Byung-Woo 한국청정기술학회 2006 청정기술 Vol.12 No.2

A simple dual sludge process, called as $KNR^{(R)}$ (Kwon's Nutrient Removal) system, was developed for small sewage treatment. It is a hybrid system that consists of an UMBR (Upflow multi-layer bioreactor) as anaerobic and anoxic reactor with suspended denitrifier and a post aerobic biofilm reactor, filled with pellet-like media, with attached nitrifier. To evaluate the stability and performance of this system for small sewage treatment, the pilot-scale $KNR^{(R)}$ plant with a treatment capacity of $50m^3/d$ was practically applied to the actual sewage treatment plant, which was under retrofit construction during pilot plant operation, with a capacity of $50m^3/d$ in a small rural community. The HRTs of a UMBR and a post aerobic biofilm reactor were about 4.7 h and 7.2 h, respectively. The temperature in the reactor varied from $18.1^{\circ}C$ to $28.1^{\circ}C$. The pilot plant showed stable performance even though the pilot plant had been the severe fluctuation of influent flow rate and BOD/N ratio. During a whole period of this study, average concentrations of $COD_{cr}$, $COD_{Mn}$, $BOD_5$, TN, and TP in the final effluent obtained from this system were 11.0 mg/L, 8.8 mg/L, 4.2 mg/L, 3.5 mg/L, 9.8 mg/L, and 0.87/0.17 mg/L (with/without poly aluminium chloride(PAC)), which corresponded to a removal efficiency of 95.3%, 87.6%, 96.3%, 96.5%, 68.2%, and 55.4/90.3%, respectively. Excess sludge production rates were $0.026kg-DS/m^3$-sewage and 0.220 kg-DS/kg-BOD lower 1.9 to 3.8 times than those in activated sludge based system such as $A_2O$ and Bardenpho.

간호실무에서 신봉이론(Espoused theories)에 대한 탐색적 연구

서문자,김혜숙,이은희,박영숙,조경숙,강현숙,임난영,김주현,이소우,조복희,이명하,지성애,하양숙,손영희,권성복,김희진,추진아 성인간호학회 2001 성인간호학회지 Vol.13 No.1

As a nursing practice involves nurses' actions in a specific context of health care, this study has focused on exploring the espoused theories in nursing practice within the action science perspectives, Espoused theories are the belief, principles, and rationale expressed by the practitioner as guiding her/his actions in a situation of practice. The data were analysed qualitatively and 25 elements of espoused theories of nursing action were identified and clustered into 6 categories. The 25 elements of espoused theories are as follows: The clinical nurse worked in wholistic and individual nursing, focussed on the patient's needed, comfort and supportive nursing (5 theories of nursing goal) ; excellent skills, knowledge based, assessment and data collection, explaining, educating or a scientific basis(6 theories of nursing intervention): advocacy, value oriented, treatment, account- ability and commitment(4 theories of nursing ethics) ; human respect. partnership, trust(3 theories of patient-nurse relationship) : knowledgable, accumulated clinical experiences and personally lived experiences. positive perspectives(4 theories of nurse), role of intervention. rewarding peer relationship(3 theories of situations) The above mentioned espoused theories are similar to that of nursing textbooks which students learned through basic nursing education and almost the same as the Acts ofa Nurse in Korean. However, we are doubtful whether nurses actually do as they think. Therefore. it is recommended to review the theories-in-use in order to and any discrepancies between the espoused theories and the reality of nursing actions

해마 theta리듬과 pyramidal neuron의 세포내 특성과의 상관관계

권오흥,조진화,남순현,김현정,최병주,김영진,이만기 大韓小兒齒科學會 1998 대한소아치과학회지 Vol.25 No.4

Eledctrophysiological phenomena of pyramidal cells in the CAI area of the dorsal hippocampus were recorded from and filled with neurobiotin in anesthetized rats. The electropharmacological properties of membrane as well as the cellular-synaptic generation of rhythmic slow activity (theta)were examined. The intracellular response characteristics of these pyramidal cells were distinctly different from responses of inteneurons. Pyramidal cells had a high resting membrane potential, a low input resistance, and a large amplitude action potential. A afterhyperpolarization was followed a single action potential. Most of pyramidal cells did not display a spontaneous firing. Pyramidal cells displayed weak inward rectification and anodal break excitation. The slope of the frequency-current relation was 53.4 Hz/nA for the first interspike interval and 15.9 Hz/nA for the last intervals, suggesting the presence of spike frequency adaptation. Neurobiotin-filled neurons showed pyramidal morphology. Cells were generally bipolar dendritc processes ramifying in stratum lacunosum-moleculare, radiatum, and oriens. Commissural stimulation discharged pyramidal cells, followed by excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs). The frequency of theat-related membrane potential oscillation was voltage-independent in pyramidal neurons. At strong depolarization levels (less than 30 mV) pyramidal cells emitted sodium spike oscillation, phase-locked to theta. The observations provide direct evidence that theta-related rhythmic hyperpolarization of principal cells is brought by the rhythmically discharging interneurons. Furthermore, the findings in which interneurons were also paced by rhythmic inhibitory postsynaptic potentials during theta suggest that they were periodically hyperpolarized by their GABAergic septal afferents.