Sensitivity of surface characteristics on the simulation of wind-blown-dust source in North America

Park, S.H.,Gong, S.L.,Gong, W.,Makar, P.A.,Moran, M.D.,Stroud, C.A.,Zhang, J. Pergamon Press ; Elsevier [distribution] 2009 Atmospheric environment Vol.43 No.19

Recently, a wind-blown-dust-emission module has been built based on a state-of-the-art wind erosion theory and evaluated in a regional air-quality model to simulate a North American dust storm episode in April 2001 (see Park, S.H., Gong, S.L., Zhao, T.L., Vet, R.J., Bouchet, V.S., Gong, W., Makar, P.A., Moran, M.D., Stroud, C., Zhang, J. 2007. Simulation of entrainment and transport of dust particles within North America in April 2001 (''Red Dust episode''). J. Geophys. Res. 112, D20209, doi:10.1029/2007JD008443). A satisfactorily detailed assessment of that module, however, was not possible because of a lack of information on some module inputs, especially soil moisture content. In this paper, the wind-blown-dust emission was evaluated for two additional dust storms using improved soil moisture inputs. The surface characteristics of the wind-blown-dust source areas in southwestern North America were also investigated, focusing on their implications for wind-blown-dust emissions. The improved soil moisture inputs enabled the sensitivity of other important surface characteristics, the soil grain size distribution and the land-cover, to dust emission to be investigated with more confidence. Simulations of the two 2003 dust storm episodes suggested that wind-blown-dust emissions from the desert areas in southwestern North America are dominated by emissions from dry playas covered with accumulated alluvial deposits whose particle size is much smaller than usual desert sands. As well, the source areas in the northwestern Texas region were indicated to be not desert but rather agricultural lands that were ''activated'' as a wind-blown-dust sources after harvest. This finding calls for revisions to the current wind-blown-dust-emission module, in which ''desert'' is designated to be the only land-cover category that can emit wind-blown dust.

Post annealing effect of flexible polymer solar cells to improve their electrical properties

Gong, S.C.,Jang, S.K.,Ryu, S.O.,Jeon, H.,Park, H.H.,Chang, H.J. Elsevier 2010 CURRENT APPLIED PHYSICS Vol.10 No.4

Flexible polymer solar cells with an ITO/PEDOT/P3HT:PCBM/Al structure were fabricated using regioregular poly(3-hexylthiophene) (P3TH) polymer:(6,6)-phenyl C61-butyric acid methyl ester (PCBM) fullerene polymer as the photovoltaic (PV) bulk hetero-junction layer. The P3HT and PCBM used as the electron donor and electron acceptor materials were spin cast on indium tin oxide (ITO) coated polyethylene naphthalate (PEN) substrates. The optimum mixing concentration ratio of the P3HT:PCBM PV layer was found to be 4:4 wt.%, at which the maximum short circuit current density (J<SUB>SC</SUB>), open circuit voltage (V<SUB>OC</SUB>), fill factor (FF) and power conversion efficiency (PCE) values were about 3.8 mA/cm<SUP>2</SUP>, 427 mV, 36.6% and 0.66%, respectively. To investigate the effects of the post annealing treatment, the as-prepared flexible polymer solar cells were post annealed at temperatures ranging from 150 <SUP>o</SUP>C to 180 <SUP>o</SUP>C for 5 min. The J<SUB>SC</SUB> and V<SUB>OC</SUB> values increased with increasing post annealing temperature from 150 <SUP>o</SUP>C to 170 <SUP>o</SUP>C, which may be due to the improvement of the light absorption coefficient of P3HT and improved ohmic contact between the PV layer and Al electrode film. The maximum J<SUB>SC</SUB>, V<SUB>OC</SUB>, FF and PCE values of the flexible polymer solar cell, which was post annealed at 170 <SUP>o</SUP>C for 5 min, were found to be about 4.3 mA/cm<SUP>2</SUP>, 616 mV, 32.6% and 0.86%, respectively.

International Cross-Sectional Survey among Healthcare Professionals on the Management of Cow’s Milk Protein Allergy and Lactose Intolerance in Infants and Children

J Armando Madrazo,Fawaz Alrefaee,Anjan Chakrabarty,Julia C. de Leon,Lanlan Geng,Sitang Gong,Ralf G. Heine,Anette Järvi,Jarungchit Ngamphaiboon,Christina Ong,Jossie M. Rogacion 대한소아소화기영양학회 2022 Pediatric gastroenterology, hepatology & nutrition Vol.25 No.3

Purpose: The present international survey among healthcare providers aimed to collect data on theoretical knowledge and clinical practices in the diagnosis and management of cow’s milk protein allergy (CMPA) and lactose intolerance (LI) in infants. Methods: A global survey was conducted in several countries with diverse health care settings. The survey consisted of multiple-choice questions in 3 main domains: (1) understanding and clinical practices around CMPA and LI; (2) case scenarios; and (3) disease-specific knowledge and potential educational needs. Results: Responses were available from 1,663 participants. About 62% of respondents were general practitioners or general pediatricians, and the remainder were pediatric allergists/gastroenterologists (18%) or other health practitioners (20%). The survey identified knowledge gaps regarding the types of CMPA (IgE-mediated vs. non-IgE-mediated) and the clinical overlap with LI. The survey suggested diverse clinical practices regarding the use of hypoallergenic formulas, as well as misconceptions about the prebiotic benefits of lactose in extensively hydrolyzed formulas in non-breastfed infants with CMPA. Responses to the two case scenarios highlighted varying levels of awareness of the relevant clinical practice guidelines. While respondents generally felt confident in managing infants with CMPA and LI, about 80% expressed an interest for further training in this area. Conclusion: The current survey identified some knowledge gaps and regional differences in the management of infants with CMPA or LI. Local educational activities among general and pediatric healthcare providers may increase the awareness of clinical practice guidelines for the diagnosis and treatment of both conditions and help improve clinical outcomes.

IEC1400-1 국제표준을 적용한 대형 수평축 풍력발전용 회전날개의 설계개선

공창덕,방조혁,정종철,감명훈,정석훈,장병섭,안주연 朝鮮大學校 機械技術硏究所 2000 機械技術硏究 Vol.3 No.2

풍력 터빈회전날개의 설계시 구조적 형상을 결정하는 예비설계 단계에서 종전에는 여러 가지 다양한 경우의 설계를 수행하여 이중 적합한 경우을 채택하는 시행착오 방법은 많은 설계시간을 요하였으나, 본 연구에서는 이 같은 설계시의 비효율적 요소를 배제하고자 적층판 이론을 기초로 한 설계프로그램을 이용하는 설계기법을 계발함으로서 설계절차를 개선하였다. 개선된 설계절차에 따라 국제표준 설계규격 IEC1400-1에서 규정한 각 경우의 하중해석과 응력, 변형율 및 변형한계를 설정한 후, 단순화한 복합재 회전날개 구조에 혼합법칙과 주 응력 설계기법을 이용하여 복합재 구조의 형상을 정하였다. 설계된 구조는 본 연구를 통해 개발된 적층판 이론을 기초로 한 프로그램을 이용하여 강도 및 좌굴에 대한 구조의 안정성을 확인하여 상세설계 과정 시 소요되는 시간을 최소화하였다. 설계된 구조는 표피 등을 고려하여 수정 설계한 후 유한요소법을 이용하여 응력, 변형율, 변위, 고유진동수, 좌굴안정성, 피로수명등을 해석하여 국제 표준규격의 만족여부를 확인하였다. Because the previous design procedure for the composite wind turbine blade structure using trial and error method takes long time, a improved design procedure by using the program based on classical laminate theory was proposed to reduce the inefficient element. According to the improved design procedure, limitation of strains, stresses and displacements specified by international standard specification IEC1400-1 for the composite wind turbine blade were applied to sizing the structural configuration by using the rule of mixture and the principal stress design technique with a simplified turbine blade. Structural safety for strength and buckling stability was confirmed by the developed analysis program based on the laminate theory to minimize the design procedure. After modifying the preliminary design result with additional structural components such as skin, foam sandwich and mounting joints, stresses, strains, displacements, natural frequency, buckling load and fatigue life were analyzed by the finite element method. Finally these results were confirmed by comparing with IEC1400-1 specification.

융모성 질환의 임상적 고찰

공지원,정두수,이승철,정은신,이형열,이영혜 예수병원 1992 예수병원학술지 Vol.13 No.-

다이아몬드 휠에 의한 세라믹 연삭의 연삭력 평가

문홍현,김성청,공재향,박병규,소의열,이근상 한국공작기계학회 2002 한국공작기계학회 춘계학술대회논문집 Vol.2002 No.-

In this study, through the experimental results of grinding ratio, grinding force and surface roughness with the obtained wear amount of diamond wheel and ceramic material during the grinding process, the following conclusions could be found. In the case of Si₃N₄, the wear of diamond wheel is large while the grinding force is stable and the range of change in surface roughness is small. For the case of Al₂O₃ and ZrO₂, while the wear of diamond wheel is getting smaller, the grinding force is increasing but the value of surface roughness is decreasing. For grinding with the vitrified bond wheel, it seems that the self-sharpening can be found for Si₃N₄ and the glazing effect of the cutting edge for Al₂O₃ and ZrO₂.

Ofloxacin에 대한 약물사용검토

심은희,김주휘,유영인,공경희,윤덕심 한국병원약사회 1996 병원약사회지 Vol.13 No.1

Drug use evaluation(DUE) is a system for assuring the quality of drug use in patient care. It was performed on ofloxacin for the purpose of presenting the more reasonable drug therapy. Fifty eight cased of patients, who had been treated with ofloxacin in Korea University Kuro Hospital form September 1. 1994 to April 30. 1995, were reviewed retrospectively. The applicated criteria for ofloxacin was "Criteria for Drug Use Evaluation" established by ASHP report 1993. The results of the analysis show that 34 cases (59%) were met with the criteria for the justification of use, while 24 cases (41%) were not. In critical indicators, several criteria including culture & sensitivity test, vital sing, WBC monitoring and urinalysis were relatively well performed showing the accepted level above 70%, while serum creatinine monitoring and administration time were infrequently performed with low accepted level. Accepted level of ofloxacin was relatively high, while notice about drug interaction and complications were low, which indicate that medication were being performed under the insufficient information about each drug in clinic. The cased met with all criteria were 13 cases (22%), all included of which were in internal medicine. From the results, it could be concluded that medical staff should get the more information on general area of antimicrobial agents include complication, duration of therapy and characteristics of each drugs.

대규모 원단 도매 시장에서의 포름알데히드 노출에 관한 연구

최상준,백남원,김지현,이미선,황정희,정현희,이은희,최연기,양윤정,이태범,이경민,공정옥,이영미 서울대학교 보건대학원 2001 서울大學校 保健環境硏究所論叢 Vol.11 No.1

This study was conducted to assessment airborne formaldehyde concentration at dry-goods stores, 'G' market and additionally at the reconstructed lecture room in the university during November, 2001. 'NIOSH 2016' method, with 2,4-DNPH treated silica gel sampler and HPLC, was used for sampling and analysis of formaldehyde concentration. Because every merchant rejects to participate in study, volunteers, pretend to customer, were involved to monitor personal exposure level. The results are summarized as follows ; 1. The geometric mean(GM) and geometric standard deviation(GSD) of TWA concentrations from 'G' market were 0.037 ppm and 2.17 respectively. 2. The TWA concentrations of the personal samples from 'G' market ranged from 0.009 to 0.065 ppm and those of the area samples from '' market ranged from 0.06 to 0.071 ppm. 3. The TWA concentrations of the area samples from reconstructed lecture room ranged from 0.022 to 0.094 ppm. The TWA concentration from latest reconstructed lecture room was higher than that of older reconstructed lecture room. 4. All of samples except one were exceeding NIOSH TWA criteria, 0.016 ppm.

Foxp3 is a key downstream regulator of p53-mediated cellular senescence

Kim, J-E,Shin, J-S,Moon, J-H,Hong, S-W,Jung, D-J,Kim, J H,Hwang, I-Y,Shin, Y J,Gong, E-Y,Lee, D H,Kim, S-M,Lee, E Y,Kim, Y S,Kim, D,Hur, D,Kim, T W,Kim, K-p,Jin, D-H,Lee, W-J Macmillan Publishers Limited 2017 Oncogene Vol.36 No.2

<P>The downstream events and target genes of p53 in the process of senescence are not fully understood. Here, we report a novel function of the forkhead transcription factor Foxp3, which is a key player in mediating T-cell inhibitory functions, in p53-mediated cellular senescence. The overexpression of Foxp3 in mouse embryonic fibroblasts (MEFs) accelerates senescence, whereas Foxp3 knockdown leads to escape from p53-mediated senescence in p53-expressing MEFs. Consistent with these results, Foxp3 expression resulted in the induction of senescence in epithelial cancer cells, including MCF7 and HCT116 cells. Foxp3 overexpression also increased the intracellular levels of reactive oxygen species (ROS). The ROS inhibitor N-acetyl-L-cysteine rescued cells from Foxp3-expression-induced senescence. Furthermore, the elevated ROS levels that accompanied Foxp3 overexpression were paralleled by an increase in p21 expression. Knockdown of p21 in Foxp3-expressing MEFs abrogated the Foxp3-dependent increase in ROS levels, indicating that Foxp3 acts through the induction of p21 and the subsequent ROS elevation to trigger senescence. Collectively, these results suggest that Foxp3 is a downstream target of p53 that is sufficient to induce p21 expression, ROS production and p53-mediated senescence.</P>

High aldehyde dehydrogenase activity enhances stem cell features in breast cancer cells by activating hypoxia-inducible factor-2α

Kim, R.J.,Park, J.R.,Roh, K.J.,Choi, A.R.,Kim, S.R.,Kim, P.H.,Yu, J.H.,Lee, J.W.,Ahn, S.H.,Gong, G.,Hwang, J.W.,Kang, K.S.,Kong, G.,Sheen, Y.Y.,Nam, J.S. Elsevier ; Elsevier Science Pub. Co 2013 Cancer letters Vol.333 No.1

High aldehyde dehydrogenase (ALDH) activity has been recognized as a marker of cancer stem cells (CSCs) in breast cancer. In this study, we examined whether inhibition of ALDH activity suppresses stem-like cell properties in a 4T1 syngeneic mouse model of breast cancer. We found that ALDH-positive 4T1 cells showed stem cell-like properties in vitro and in vivo. Blockade of ALDH activity reduced the growth of CSCs in breast cancer cell lines. Treatment of mice with the ALDH inhibitor diethylaminobenzaldehyde (DEAB) significantly suppressed 4T1 cell metastasis to the lung. Recent evidence suggests that ALDH affects the response of stem cells to hypoxia; therefore, we examined a possible link between ALDH and hypoxia signaling in breast cancer. Hypoxia-inducible factor-2α (HIF-2α) was highly dysregulated in ALDH-positive 4T1 cells. We observed that ALDH was highly correlated with the HIF-2α expression in breast cancer cell lines and tissues. DEAB treatment of breast cancer cells reduced the expression of HIF-2αin vitro. In addition, reduction of HIF-2α expression suppressed in vitro self-renewal ability and in vivo tumor initiation in ALDH-positive 4T1 cells. Therefore, our findings may provide the evidence necessary for exploring a new strategy in the treatment of breast cancer.