Nationwide survey to evaluate the prevalence of varicoceles in South Korean middle school boys: A population based study

Baek, Minki,Park, Seong Woon,Moon, Kyung Hyun,Chang, Young Seop,Jeong, Hee Jong,Lee, Sang Wook,Han, Sang Won,Kim, Young Sig Blackwell Publishing Asia 2011 International journal of urology Vol.18 No.1

<P><B>Objective: </B> We carried out a nationwide epidemiological study to evaluate the prevalence and effect of varicoceles on testicular volume in South Korean adolescents. We also investigated the correlation between varicoceles and body mass index (BMI).</P><P><B>Methods: </B> In this prospective study, physical examinations were carried out to assess the presence and severity of varicoceles in middle school boys from six regions of South Korea. Testicular volume, height and weight of all boys were measured. The prevalence of varicoceles was assessed. The associations between age, testicular volume, BMI, and the presence and severity of varicoceles were examined.</P><P><B>Results: </B> A total of 1938 boys with a mean age of 14.1 years (range 13–16 years) were screened. A varicocele was found on the left side in 295 (15.2%) boys and on the right side in 8 (0.4%) boys. Bilateral varicoceles were found in 17 (0.9%) individuals. Of the subjects with a left varicocele, 151 (51.2%), 80 (27.1%) and 64 (25.1%) boys had a grade 1, 2 or 3 varicocele, respectively. The prevalence of varicoceles did not increase with age. The proportion of boys with testicular size discrepancies increased with the severity of the varicocele. After adjusting for age, BMI had a negative correlation with the presence of varicoceles.</P><P><B>Conclusions: </B> The prevalence of varicoceles in South Korean middle school boys is 16.5%. The presence of varicoceles seems to have a negative effect on testicular growth. BMI has a significant inverse relationship with the occurrence of varicoceles.</P>

트랜지스터용 p-형 산화물 반도체(니켈 산화물, 주석 산화물, 구리 산화물) 최신 동향 분석

최민기(Minki Choe),전다희(Dahui Jeon),황인홍(Inhong Hwang),백인환(In-Hwan Baek) 한국세라믹학회 2023 세라미스트 Vol.26 No.1

Over the past decade, many research groups have been striving to develop high-performance p-type switching oxide materials for implementing complementary metal-oxide-semiconductor (CMOS) thin film devices. However, realizing p-type oxide thin film transistors (TFTs) whose electrical properties are comparable to n-type oxide TFTs has been challenging. This is because of inherent characteristics of p-type oxide materials such as the high formation energy of native acceptors and high hole effective mass caused by localized hole transport path. Developing a p-type oxide with a delocalized hole transport pathway and low hole formation energy is crucial for the production of CMOS circuits utilizing oxide thin films. NiO, SnO, and CuOx are being actively studied as candidate materials that satisfy these requirements. This review discusses the latest advances in the synthesis method of p-type binary oxide thin films and the approach for electrical performance enhancement.

지역난방 시스템의 순환수에 따른 보일러 튜브의 부식 특성

홍민기 ( Minki Hong ),조정민 ( Jeongmin Cho ),송민지 ( Min Ji Song ),김우철 ( Woo Cheol Kim ),하태백 ( Tae Baek Ha ),이수열 ( Soo Yeol Lee ) 한국부식방식학회(구 한국부식학회) 2018 Corrosion Science and Technology Vol.17 No.6

In this study, corrosion behavior of a SA178-A alloy used in the boiler tube of a district heating system was investigated in different environments where it was exposed to pure water, district heating (DH) water, and filtered district heating (FDH) water. After the corrosion test, the surface morphology was examined for observation of the number of pitting sites and pitting area fraction, using a scanning electron microscope. The DH water and FDH water conditions resulted in a lower corrosion potential and pitting potential, and revealed a significantly higher corrosion rate than the pure water condition. The pitting sites in the DH water (pH 9.6) were approximately eighteen times larger than those in the pure water (pH 9.6). Compared to the DH water, the corrosion potential became more noble in the FDH water condition, where iron ions were reduced through filtration. However, the corrosion rate increased in the FDH water due to an increased concentration of chloride ions, which deteriorated the stability of passive film.

Computational Exploration for Lead Compounds That Can Reverse the Nuclear Morphology in Progeria

Rampogu, Shailima,Baek, Ayoung,Son, Minky,Zeb, Amir,Park, Chanin,Kumar, Raj,Lee, Gihwan,Kim, Donghwan,Choi, Yeonuk,Cho, Yeongrae,Park, Yohan,Park, Seok Ju,Lee, Keun Woo Hindawi 2017 BioMed research international Vol.2017 No.-

<P>Progeria is a rare genetic disorder characterized by premature aging that eventually leads to death and is noticed globally. Despite alarming conditions, this disease lacks effective medications; however, the farnesyltransferase inhibitors (FTIs) are a hope in the dark. Therefore, the objective of the present article is to identify new compounds from the databases employing pharmacophore based virtual screening. Utilizing nine training set compounds along with lonafarnib, a common feature pharmacophore was constructed consisting of four features. The validated Hypo1 was subsequently allowed to screen Maybridge, Chembridge, and Asinex databases to retrieve the novel lead candidates, which were then subjected to Lipinski's rule of 5 and ADMET for drug-like assessment. The obtained 3,372 compounds were forwarded to docking simulations and were manually examined for the key interactions with the crucial residues. Two compounds that have demonstrated a higher dock score than the reference compounds and showed interactions with the crucial residues were subjected to MD simulations and binding free energy calculations to assess the stability of docked conformation and to investigate the binding interactions in detail. Furthermore, this study suggests that the Hits may be more effective against progeria and further the DFT studies were executed to understand their orbital energies.</P>

A two-storey structured photoanode of a 3D Cu2ZnSnS4/CdS/ZnO@steel composite nanostructure for efficient photoelectrochemical hydrogen generation

Choi, Youngwoo,Baek, Minki,Zhang, Zhuo,Dao, Van-Duong,Choi, Ho-Suk,Yong, Kijung The Royal Society of Chemistry 2015 Nanoscale Vol.7 No.37

<P>A two-storey structured photoanode of a 3D Cu2ZnSnS4(CZTS)/CdS/ZnO@steel composite nanostructure has been fabricated by using the solution method and demonstrated highly efficient photoelectrochemical hydrogen generation due to its contraption in the structure for sufficient light absorption as well as the three step-down band alignments for efficient charge separation and transport. This composite structure is composed of two storeys: the upper storey is the CZTS/CdS/ZnO hetero-nanorods (NRs) covered on the stainless steel mesh; the bottom storey is the CZTS/CdS/ZnO hetero-NRs grown on the FTO glass. The CZTS/CdS/ZnO hetero-NRs have cascade band gaps decreasing from 3.15 to 1.82 eV, which gives them efficient charge transfer and broad photoresponse in the UV to near-IR region, resulting in 47% IPCE in a wide light region from 400 to 500 nm; and the stainless steel mesh serves not only as a conductor for charge transport, but also as a skeleton of the grid structure for absorbing more light. The related mechanism has been investigated, which demonstrates that the two-storey CZTS/CdS/ZnO@steel composite nanostructure would have great potential as a promising photoelectrode with high efficiency and low cost for PEC hydrogen generation.</P>

기계 학습을 활용한 직접 암모니아 고체산화물 연료전지 작동 제어

백재완(Jaewan Baek),김진우(Jinwoo Kim),이현호(Hyunho Lee),이민기(Minki Lee),최민기(Mingi Choi) 대한기계학회 2024 대한기계학회 춘추학술대회 Vol.2024 No.4

Developing cheap and sustainable Hydrogen Evolution Reaction Catalyst NIMoFe in Alkaline Solution

Hyogyun Roh,Minki Baek,Zhuo Zhang,Kijung Young 한국진공학회 2019 한국진공학회 학술발표회초록집 Vol.2019 No.8

An unconventional outer-to-inner synthesis strategy for core (Au)-shell nanostructures with photo-electrochemical enhancement

Zhang, Zhuo,Baek, Minki,Song, Hongseon,Yong, Kijung The Royal Society of Chemistry 2017 Nanoscale Vol.9 No.16

<P>In this work, an outer-to-inner strategy is demonstrated to simultaneously fabricate core-shell NPs and assemble them onto a scaffold. Specifically, the shell material is deposited onto the scaffold first, and then a layer of the core material (Au) is covered on the shell surface. Finally, the core (Au)-shell nanoparticles (NPs) are formed on the scaffold after annealing. As examples, Au-Bi2S3, Au-CdS and Au-CdSe coreshell NPs are grown on the surface of ZnO nanorods (NRs) via this strategy and exhibit enhanced photoelectrochemical (PEC) efficiency. The enhanced PEC performance is ascribed to improved light absorption induced by the plasmonic effect, trapped electrons of Au NPs, and cascade band alignment of the shell material and ZnO. The synthetic method gives a universal route to the development of nanodevices with assembled core-shell NPs. The core-shell NPs in the current study possess significant potential as building blocks for future PEC anodes or other solar conversion systems.</P>

Comparison of Surgical Outcomes of Laparoscopic Adrenalectomy Between Patients With Nonfunctioning Adrenal Adenomas and Subclinical Cushing Syndrome

Minyong Kang,Minki Baek,Jonghoon Lee,Byong Chang Jeong 대한비뇨기종양학회 2017 대한비뇨기종양학회지 Vol.15 No.3

Purpose: To examine and compare the perioperative outcomes of laparoscopic adrenalectomy (LA) and to determine its efficacy in patients with nonfunctioning adrenal adenomas (NFA) and subclinical Cushing syndrome (SCS). Materials and Methods: We retrospectively analyzed the clinical data obtained from 79 consecutive patients who underwent LA for the treatment of either NFA (n=35) or SCS (n=44) between 2011 and 2016. All patients had undergone computed tomography, as well as endocrinological tests to confirm the diagnosis prior to the adrenalectomy. The primary endpoint was improved metabolic parameters relating to diabetes, hypertension, dyslipidemia, and obesity. Results: Patients with SCS compared to those with NFA showed a higher occurrence of diabetes (29.5% vs. 11.4%), hypertension (59.1% vs. 34.3%), and dyslipidemia (43.2% vs. 14.3%). Patients with SCS showed a smaller median tumor size compared to those with NFA (2.5 cm vs. 5 cm). No significant perioperative complications ≥ Clavien-Dindo classification grade III were observed in any patient (SCS or NFA group). In terms of their metabolic profile, patients with SCS showed a significant postoperative improvement in hypertension (50.0%), diabetes (53.9%), dyslipidemia (31.6%), and obesity (29.2%). However, patients with NFA showed a postoperative improvement only in dyslipidemia (40.0%) and obesity (4.8%). Conclusions: Owing to absence of significant perioperative complications and the marked postoperative improvement in metabolic impairment, LA is a useful treatment strategy in patients diagnosed with SCS. In contrast, LA was not observed to show beneficial effects in correcting/improving the metabolic profile in patients presenting with NFA.

An antenna/spacer/reflector based Au/BiVO₄/WO₃/Au nanopatterned photoanode for plasmon-enhanced photoelectrochemical water splitting

Chen, Bin,Zhang, Zhuo,Baek, Minki,Kim, Sangkuk,Kim, Wooyul,Yong, Kijung Elsevier 2018 Applied Catalysis B Vol.237 No.-

<P><B>Abstract</B></P> <P>BiVO<SUB>4</SUB> is one of the most promising photoanodes for photoelectrochemical (PEC) water splitting. However, BiVO<SUB>4</SUB> is limited by less-than-unity efficiencies of light absorption and charge separation due to a trade-off between the long penetration depth of photons and relatively short length carrier diffusion. Here, an antenna/spacer/reflector based Au/BiVO<SUB>4</SUB>/WO<SUB>3</SUB>/Au nanopatterned photoanode is designed by integrating ultrathin BiVO<SUB>4</SUB> layer between two kinds of Au nanospheres (NSs) with different sizes. The large underlying nanopatterned Au NSs sever as current collector and back reflector to reflect the incident light by Bragg reflection of the highly ordered Au NSs array, while the small surface Au NSs act as antennas to absorb the incident and reflected light, which concentrates the light energy to the BiVO<SUB>4</SUB> layer. Moreover, a strong electromagnetic field is created in the BiVO<SUB>4</SUB> spacer due to the coupling interaction between the reflector and antenna, which promotes the charge separation of BiVO<SUB>4</SUB>. Based on this unique antenna/spacer/reflector structure, the ultrathin BiVO<SUB>4</SUB> of only 70 nm achieves a photocurrent density of 1.31 mA/cm<SUP>2</SUP> at 1.23 V<SUB>RHE</SUB>, which demonstrates an impressive 3.23 fold enhancement by the combined plasmonic effects, and it further increases to 1.97 mA/cm<SUP>2</SUP> after depositing FeOOH catalyst. The strategy paves a way for other semiconductors and thin-film optoelectronic devices to improve their performance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nanopatterned Au/BiVO<SUB>4</SUB>/WO<SUB>3</SUB>/Au is designed for the plasmon-enhanced PEC water splitting. </LI> <LI> Au/BiVO<SUB>4</SUB>/WO<SUB>3</SUB>/Au can concentrate the light energy and promote the charge seperation. </LI> <LI> Au/BiVO<SUB>4</SUB>/WO<SUB>3</SUB>/Au shows greatly higher current and negative shift of the onset potential. </LI> <LI> It provides a novel strategy for the design of thin-film optoelectronic systems. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>