Strategy for enhancing the solar-driven water splitting performance of TiO₂ nanorod arrays with thin Zn(O,S) passivated layer by atomic layer deposition

Shin, S.W.,Suryawanshi, M.P.,Hong, H.K.,Yun, G.,Lim, D.,Heo, J.,Kang, S.H.,Kim, J.H. Pergamon Press 2016 ELECTROCHIMICA ACTA Vol.219 No.-

An array of one dimensional (1D) TiO<SUB>2</SUB> nanorods (TONRs) has been regarded as an attractive candidate for electrochemical energy conversion and as storage device due to its large surface area, effiective light scattering, and undisturbed charge transport pathway. However, the high defect/trap densities on surface of the nanostructured morphology and architecture may generally hinder the performance enhancement by providing electron-hole recombination sites. Hence, the surface passivation of nanoarchitectures based photoelectrodes has recently received much attention as an effective strategy to enhance the charge-separation and charge-transfer processes in photoelectrochemical (PEC) water splitting devices. In particular, a coating layer with narrowing band gap materials can promote enhanced light harvesting in the UV-vis region as well as surface passivation, directly supplying a driving force for charge separation and charge transfer due to band alignment. In this paper, the surface of TONRs were passivated by 10 and 30nm thick Zn(O,S) layers with a relatively narrow band gap using an atomic layer deposition technique to modulate the thickness exactly. The 10nm Zn(O,S)/TONR array exhibits a significantly enhanced photocurrent density (J<SUB>sc</SUB>) of 5.94mA/cm<SUP>2</SUP> at 1.23eV vs NHE and an incident photon-to-electron conversion efficiency (IPCE) of 49% at 374nm compared with that of TONR arrays (J<SUB>sc</SUB> of 1.99mA/cm<SUP>2</SUP> at 1.23eV vs NHE and an IPCE of 20% at 380nm). However, the PEC performance is worse in the 30nm Zn(O,S)/TONR arrays, showing a J<SUB>sc</SUB> of 3.09mA/cm<SUP>2</SUP> at 1.23eV vs NHE and an IPCE of 29% at 374nm. To clearly demonstrate these PEC behaviors, the TONR and Zn(O,S)/TONR arrays were characterized by electrochemical impedance spectroscopy (EIS), open circuit voltage decay (OCV) measurement, and X-ray photoelectron spectroscopy (XPS). The above mentioned characterizations indicate that the enhanced PEC performance of the 10nm Zn(O,S)/TONR array resulted from the (i) increased light harvesting in the UV-vis region, (ii) lower charge transfer resistance and (iii) high value of valence band offset (VBO, -1.44eV) and conduction band offset (CBO, -1.2eV) than those of the TONR. However, the deterioration of J<SUB>sc</SUB> in the 30nm Zn(O,S)/TONR array is attributed to the negative value of VBO (-0.13eV) and positive value of CBO (+0.27eV), as well as the higher charge transfer resistance to the electrolyte than that of the TONR arrays, despite of the improved light absorption in the visible region. The photocurrent densities of 10nm Zn(O,S)/TONR and 30nm Zn(O,S)/TONR photocathodes decay to 4.718mA/cm<SUP>2</SUP> (5.90mA/cm<SUP>2</SUP> at 0min) and 2.212mA/cm<SUP>2</SUP> (3.03mA/cm<SUP>2</SUP> at 0min) after 90min, respectively, they retain of about~80% and 70% of its original values. These experimental results and discussions not only provide the physical insights into the surface passivation effect and band alignment but also can open a promising route to design the thin passivation layer having the narrowing band gap energy (1.0eV~2.5eV) on the 1D TiO<SUB>2</SUB> nanostructure for further enhanced performance and realization of a TiO<SUB>2</SUB> based PEC system.

Quantifying herbicide dose-response and resistance in <i>Echinochloa</i> spp. by measuring root length in growth pouches

Zhang, C. J.,Lim, S. H.,Kim, J. W.,Song, J. S.,Yook, M. J.,Nah, G.,Valverde, B. E.,Kim, D. S. Canadian Science Publishing 2015 Canadian journal of plant science. Revue canadienn Vol.95 No.6

<P> Zhang, C. J., Lim, S. H., Kim, J. W., Song, J. S., Yook, M. J., Nah, G., Valverde, N. E. and Kim, D. S. 2015. Quantifying herbicide dose-response and resistance in Echinochloa spp. by measuring root length in growth pouches. Can. J. Plant Sci. 95: 1181-1192. The aim of the presented study was to develop a bioassay for rapid diagnosis of herbicide dose-response and resistance in Echinochloa. Pre-germinated seeds of Echinochloa spp. were incubated in growth pouches (18 cm×16.5 cm) containing herbicide solutions in a range of concentrations. Shoot and root lengths were measured after 6 d of incubation. Dose-responses estimated by measuring root lengths in the growth pouches were well-described by the log-logistic dose-response model and similar to those estimated by a whole-plant assay. Accurate dose-response curves were successfully generated for several herbicides with different modes of action, suggesting that the growth pouch method can be used for herbicide bioassays. The suitability of the growth pouch method for rapid diagnosis of acetyl coenzyme-A carboxylase (ACCase) and acetolactate synthase (ALS) inhibitor resistance in Echinochloa spp. was also tested. For cyhalofop-butyl, resistant and susceptible biotypes were discriminated at 180-300 mg a.i. L<SUP>−1</SUP> and 80-120 mg a.i. L<SUP>−1</SUP> for barnyardgrass (E. crus-galli) and late watergrass (E. oryzicola), respectively. For penoxsulam, the discriminatory dosage was 350-500 mg a.i. L<SUP>−1</SUP> for barnyardgrass and 650-1000 mg a.i. L<SUP>−1</SUP> for late watergrass. The method was further used to identify late watergrass biotypes resistant and susceptible to two other ALS inhibitors, azimsulfuron and bispyribac-sodium. Our results show that the growth pouch method can be reliably used in herbicide dose-response studies and to diagnose herbicide resistance in Echinochloa spp., with significant time and cost savings compared with conventional whole-plant assays. </P>

세관 양광주 방전에서 플라즈마 확산의 완전 해

김동준,정종문,김정현,황하청,정재윤,조윤희,임현교,구제환,최은하,조광섭,Jin, D.J.,Jeong, J.M.,Kim, J.H.,Hwang, H.C.,Chung, J.Y.,Cho, Y.H.,Lim, H.K.,Koo, J.H.,Choi, E.H.,Cho, G.S. 한국진공학회 2010 Applied Science and Convergence Technology Vol.19 No.1

관경이 수 mm인 세관 램프 내부에서 플라즈마의 확산을 조사하기 위하여 이극성(ambipolar) 확산방정식을 해하였다. 반경 방향의 확산에 의한 유리관 벽에서의 플라즈마 소멸 특성시간은 $\tau_r\;=\;(r_0/2.4)^2/D_a$로 주어진다. 반경 $r_0{\sim}1\;mm$이고 이극성 확산계수 $D_a{\sim}0.01\;m^2/s$ 이면, $\tau_r{\sim}17\;{\mu}s$이다. 이는 램프의 교류전원 구동에서 플라즈마를 유지하기 위한 구동 최소 주파수 ~30 kHz에 해당한다. 고전압이 인가되는 전극부에 발생한 고밀도의 플라즈마가 양광주로 확산되는 특성시간은 $\tau_z{\sim}0.1\;s$이다. 고밀도 플라즈마 경계에서의 시간에 대한 확산속도는 $t{\sim}10^{-6}\;s$일 때 $u_D{\sim}10^2\;m/s$이고, $t{\sim}10^{-3}\;s$이면 그 속도는 $u_D{\sim}1\;m/s$로 느려진다. 따라서 램프 길이 ~1 m에 대하여 전극부에서 생성된 고밀도 플라즈마가 양광주 전체로 확산되는 시간은 수 초가 걸린다. The ambipolar diffusion equation has been solved in a fine-tube lamp of a few mm in diameter. In the diffusion of radial direction, the plasma diffuses and vanishes away at the glass wall by recombination with the characteristic time of plasma loss is given by $\tau_r\;=\;(r_0/2.4)^2/D_a$. With the radius $r_0{\sim}1\;mm$ and the ambipolar diffusion coefficient $D_a{\sim}0.01\;m^2/s$, the vanishing time is calculated $\tau_r{\sim}10\;{\mu}s$ which corresponds to the least value of frequency 30 kHz for the sustaining the plasma in the operation of high voltage AC-power. In the diffusion of longitudinal z-direction, a high density plasma generated at the area of a high voltage electrode, diffuses into the positive column with the characteristic time $\tau_z{\sim}0.1\;s$. The plasma diffusion velocity at the boundary of high density plasma is $u_D{\sim}10^2\;m/s$ at the time $t{\sim}10^{-6}$ s and the diffusion velocity becomes slow as $u_D{\sim}1\;m/s$ at $t{\sim}10^{-3}\;s$. Therefore, for the long lamp of 1 m, it takes about several seconds for the high density plasma at the area of electrode to diffuse through the whole positive column space.

한국잔디 수집계통들 중에서 우수계통들의 생육특성 비교

임용우(Y. W. Rim),김기용(K. Y. Kim),김맹중(M. J. Kim),성병렬(B. R. Sung),임영철(Y. C. Lim),정의수(E. S. Chung),신홍균(H. K. Shin),김용선(Y. S. Kim) 한국잡초학회·한국잔디학회 2003 Weed & Turfgrass Science Vol.17 No.2,3

2001년 수집된 한국잔디 133계통들 중에서 우수한 계통들을 선발하기위하여 밀도(품질),<br/> 피복성, 녹색기간, 내병성, 출수유무(종자수) 등의 주요특성과 그 외 생육특성들이 조사되었다. 생육특성이 우수한 6계통이 선발되었으며 그 결과를 요약하면 다음과 같다.<br/> 수집된 133계통들 중에서 가장 녹색기간이긴 계통은 J01067으로 11월초까지 녹색도를 유지하였다. J01106 및 J01129 계통들은 엽폭이 각각 1.5mm 및 2mm 정도로 매우 좁으며, 밀도가 높고, 피복성도 좋은 것으로 나타났으며, 내병성도 강하였다. J01122 계통은 들잔디 계통들 중에서 유일하게 내병성이 강한 계통으로 선발되었다. J01128 계통은 엽폭이 3.2mm로 중엽에 속하였으며, 대비품종인 Sunburst 와 비슷하였다. 이 계통의 경우도J01106, J01129 계통들과 마찬가지로 밀도가 높고 내병성이 강한 것으로 나타났다.<br/> 수집된 133계통들의 형태적 분류를 위하여 5가지의 생육특성을 사용하여 크게 세가지 군집<br/> 으로 분류하였으며, 그 중에서 대비품종으로 사용된 6품종들과 선발된 우수 6계통의 분류는<br/> 다음과 같다. 제 1군집에 속하는 품종 및 계통은 Belare, Meyer, 안양중지(Anyang-jungji), J01067, J01112 등이 포함되었으며, 제 2군집으로는 S-94, J01105가 포함되었고, 제 3군집에는 Sunburst, 건희(Konhee), J01106, J01128, J01129 등이 포함되었다. Growth characteristics such as density(quality), covering speed, green period, disease resistance, heading existence(number of seeds) and other characteristics were examined for selection of superior lines among the 133 zoysiagrass lines collected in 2001. Six superior lines were selected and the results were summarized as follows.<br/> Superior line, J01067 was longest for green period among the 133 zoysiagrasses and stayed green until the beginning of November. Leaf width of J01106 and J01129 lines was very narrow as 1.5㎜ and 2㎜, respectively and superior for density(quality), covering speed and disease resistance. J01122 line was selected for strongest disease resistance among the lines of Zoysia japonica. Leaf width of J01128 was 3.2㎜ showing midium type and similar to standard cultivar, Sunburst. This line also showed higher density and strong disease resistance like J01106 and J01129.<br/> Five growth characteristics for morphological classification of 133 zoysiagrass lines<br/> was used and divided into 3 cluster groups. Of 133 lines, 6 standard cultivars and 6 superior lines were classified as follows. First cluster group contained Belare, Meyer, Anyang-jungji, J01067, J01122, and second group contained S-94 and J01105, and third group contained Sunburst, Konhee, J01106, J01128 and J01129.<br/> <br/>

Analysis of the relationship between the kinetic energy and intensity of rainfall in Daejeon, Korea

Lim, Y.S.,Kim, J.K.,Kim, J.W.,Park, B.I.,Kim, M.S. Pergamon Press 2015 QUATERNARY INTERNATIONAL Vol.384 No.-

The kinetic energy and momentum of rainfall are widely used as erosivity indicators for estimating soil detachment (erosion) induced by the impact of raindrops. Because direct measurements of the force or kinetic energy of rainfall on ground surfaces are not widely available, many empirical relationships have been derived to link the kinetic energy and intensity (I) of rainfall, the factor that has the most control over soil erosion and is readily accessible. This study considered three rainfall erosivity indices: kinetic energy expenditure (KE<SUB>time</SUB>, J m<SUP>-2</SUP> h<SUP>-1</SUP>), kinetic energy content (KE<SUB>mm</SUB>, J m<SUP>-2</SUP> mm<SUP>-1</SUP>), and momentum (M, kg m s<SUP>-1</SUP> m<SUP>-2</SUP> s<SUP>-1</SUP> or N m<SUP>-2</SUP>). The relationships between these rainfall erosivity indices (KE<SUB>time</SUB>, KE<SUB>mm</SUB>, and M) and rainfall intensity were established by fitting to an existing functional model based on measurements of the number of drops by size and terminal velocity made from January 2010 to July 2011 using a laser optical disdrometer in Daejeon City, Korea. The best fit for the relationship between the three kinetic energy indices and rainfall intensity was obtained with a power law (KE<SUB>time</SUB>-I, and M-I) and an exponential model (KE<SUB>mm</SUB>-I). Validation results for two different events indicated good performance for the KE<SUB>time</SUB>-I and M-I equations, with a similar distribution of observed data and power-law curve fitting. However, the rainfall momentum index produced much lower uncertainty as determined from the measured terminal velocity when the equipment was exposed to in situ changeable conditions. Therefore, we suggest that the power-law relationship between momentum and rainfall intensity is the most suitable equation for the prediction of rainfall erosivity.

Predictive risk factors for Listeria monocytogenes meningitis compared to pneumococcal meningitis: a multicenter case–control study

Lim, S.,Chung, D. R.,Kim, Y. S.,Sohn, K. M.,Kang, S. J.,Jung, S. I.,Kim, S. W.,Chang, H. H.,Lee, S. S.,Bae, I. G. Springer Science + Business Media 2017 Infection Vol.45 No.1

<P>Patients with a prior history of receiving immunosuppressive therapy within 1 month and chronic liver disease have 8.1-fold and 5-fold increased risk of meningitis by L. monocytogenes compared to S. pneumoniae, respectively.</P>

Antimicrobial Susceptibility of Coagulase-Negative Staphylococci Isolated from Bovine Mastitis Between 2003 and 2008 in Korea

( J. M. Kim ),( S. K. Lim ),( J. S. Moon ),( Nam H. M. ),( H. M. Kang ),( G. C. Jang ),( S. H. Wee ),( Y. S. Joo ),( S. C. Jung ) 한국미생물 · 생명공학회 2010 Journal of microbiology and biotechnology Vol.20 No.10

A total of 1,444 coagulase-negative staphylococci (CNS) isolates from bovine mastitic milk samples collected during 2003-2008 in Korea were identified to the species level. Of 14 species identified, S. simulans, S. haemolyticus, and S. sciuri accounted for over 60% of the isolates. All the CNS isolates were tested for susceptibility to eight antimicrobials commonly used in dairy cattle. With a few exceptions, similar resistance patterns were observed among the CNS species: penicillin and ampicillin showed the lowest activity, whereas amikacin, cephalothin, and gentamicin were highly effective. About 39% (557/1,444) of the CNS isolates were pan-susceptible, whereas 12% (175/1,444) showed resistance to four or more antimicrobials tested.

Genetic dissection of the biosynthetic route to gentamicin A2 by heterologous expression of its minimal gene set

Park, J. W.,Hong, J. S. J.,Parajuli, N.,Jung, W. S.,Park, S. R.,Lim, S.-K.,Sohng, J. K.,Yoon, Y. J. Proceedings of the National Academy of Sciences 2008 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.105 No.24

<P>Since the first use of streptomycin as an effective antibiotic drug in the treatment of tuberculosis, aminoglycoside antibiotics have been widely used against a variety of bacterial infections for over six decades. However, the pathways for aminoglycoside biosynthesis still remain unclear, mainly because of difficulty in genetic manipulation of actinomycetes producing this class of antibiotics. Gentamicin belongs to the group of 4,6-disubstituted aminoglycosides containing a characteristic core aminocyclitol moiety, 2-deoxystreptamine (2-DOS), and the recent discovery of its biosynthetic gene cluster in Micromonospora echinospora has enabled us to decipher its biosynthetic pathway. To determine the minimal set of genes and their functions for the generation of gentamicin A(2), the first pseudotrisaccharide intermediate in the biosynthetic pathway for the gentamicin complex, various sets of candidate genes from M. echinospora and other related aminoglycoside-producing strains were introduced into a nonaminoglycoside producing strain of Streptomyces venezuelae. Heterologous expression of different combinations of putative 2-DOS biosynthetic genes revealed that a subset, gtmB-gtmA-gacH, is responsible for the biosynthesis of this core aminocyclitol moiety of gentamicin. Expression of gtmG together with gtmB-gtmA-gacH led to production of 2'-N-acetylparomamine, demonstrating that GtmG acts as a glycosyltransferase that adds N-acetyl-d-glucosamine (GLcNA) to 2-DOS. Expression of gtmM in a 2'-N-acetylparomamine-producing recombinant S. venezuelae strain generated paromamine. Expression of gtmE in an engineered paromamine-producing strain of S. venezuelae successfully generated gentamicin A(2), indicating that GtmE is another glycosyltransferase that attaches d-xylose to paromamine. These results represent in vivo evidence elucidating the complete biosynthetic pathway of the pseudotrisaccharide aminoglycoside.</P>

The LIM-only transcription factor LMO2 determines tumorigenic and angiogenic traits in glioma stem cells

Kim, S-H,Kim, E-J,Hitomi, M,Oh, S-Y,Jin, X,Jeon, H-M,Beck, S,Jin, X,Kim, J-K,Park, C G,Chang, S-Y,Yin, J,Kim, T,Jeon, Y-j,Song, J,Lim, Y C,Lathia, J D,Nakano, I,Kim, H Macmillan Publishers Limited 2015 CELL DEATH AND DIFFERENTIATION Vol.22 No.9

Glioblastomas (GBMs) maintain their cellular heterogeneity with glioma stem cells (GSCs) producing a variety of tumor cell types. Here we interrogated the oncogenic roles of Lim domain only 2 (LMO2) in GBM and GSCs in mice and human. High expression of LMO2 was found in human patient-derived GSCs compared with the differentiated progeny cells. LMO2 is required for GSC proliferation both in vitro and in vivo, as shRNA-mediated LMO2 silencing attenuated tumor growth derived from human GSCs. Further, LMO2 is sufficient to induce stem cell characteristics (stemness) in mouse premalignant astrocytes, as forced LMO2 expression facilitated in vitro and in vivo growth of astrocytes derived from Ink4a/Arf null mice and acquisition of GSC phenotypes. A subset of mouse and human GSCs converted into vascular endothelial-like tumor cells both in vitro and in vivo, which phenotype was attenuated by LMO2 silencing and promoted by LMO2 overexpression. Mechanistically, the action of LMO2 for induction of glioma stemness is mediated by transcriptional regulation of Jagged1 resulting in activation of the Notch pathway, whereas LMO2 directly occupies the promoter regions of the VE-cadherin gene for a gain of endothelial cellular phenotype. Subsequently, selective ablation of human GSC-derived VE-cadherin-expressing cells attenuated vascular formation in mouse intracranial tumors, thereby significantly prolonging mouse survival. Clinically, LMO2 expression was elevated in GBM tissues and inversely correlated with prognosis of GBM patients. Taken together, our findings describe novel dual roles of LMO2 to induce tumorigenesis and angiogenesis, and provide potential therapeutic targets in GBMs.

간호대생과 비보건계열 여대생의 미세먼지 위험에 대한 인식과 지식, 건강 관리행위 비교 연구

김선미,김슬기,김진선,박주형,배다희,유수빈,유영주,임지향,최유진,Chen Mengyao,양숙자,손지희 이화여자대학교 간호과학대학 2019 이화간호학회지 Vol.- No.53

Purpose: This study aimed to know whether there is a comparison of perception, knowledge and health promoting behaviors about particular matter between nursing students and non-health departments college students. Methods: A quantitative research is used. Data were collected from August 1 to 19. The study sample was nursing students and non-health departments students. For the similar condition of samples, this study excluded whose first language is not Korean. Independent T-test and pearson’s correlation was used for this study. Results: A significant positive correlation did not existed between difference of major and perception(t=0.017, p=0.986), knwledge(t=0.652, p=.516) and health promoting behaviors(t=-0.114, p=.910) about particular matters. Conclusion: Based on the study results, there is no significant correlation of perception and actions about particular matters between nursing students and non-health department college students.