http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Response of Saccharomyces cerevisiae to Stress-Free Acidification
Allen Kuan-Liang Chen,Cristy Gelling,Peter L. Rogers,Ian W. Dawes,Bettina Rosche 한국미생물학회 2009 The journal of microbiology Vol.47 No.1
Genome-wide transcriptional analysis of a Saccharomyces cerevisiae batch culture revealed that more than 829 genes were regulated in response to an environmental shift from pH 6 to pH 3 by added sulfuric acid. This shift in pH was not detrimental to the rate of growth compared to a control culture that was maintained at pH 6 and the transcriptional changes most strikingly implicated not up- but down-regulation of stress responses. In addition, the transcriptional changes upon acid addition indicated remodeling of the cell wall and central carbon metabolism. The overall trend of changes was similar for the pH-shift experiment and the pH 6 control. However, the changes in the pH 6 control were much weaker and occurred 2.5 h later than in the pH-shift experiment. Thus, the reaction to the steep pH decrease was an immediate response within the normal repertoire of adaptation shown in later stages of fermentation at pH 6. Artificially preventing the yeast from acidifying the medium may be considered physiologically stressful under the tested conditions.
Exploring the Chemical Sensitivity of a Carbon Nanotube/Green Tea Composite
Chen, Yanan,Lee, Yang Doo,Vedala, Harindra,Allen, Brett L.,Star, Alexander American Chemical Society 2010 ACS NANO Vol.4 No.11
<P>Single-walled carbon nanotubes (SWNTs) possess unique electronic and physical properties, which make them very attractive for a wide range of applications. In particular, SWNTs and their composites have shown a great potential for chemical and biological sensing. Green tea, or more specifically its main antioxidant component, epigallocatechin gallate (EGCG), has been found to disperse SWNTs in water. However, the chemical sensitivity of this SWNT/green tea (SWNT/EGCG) composite remained unexplored. With EGCG present, this SWNT composite should have strong antioxidant properties and thus respond to reactive oxygen species (ROS). Here we report on fabrication and characterization of SWNT/EGCG thin films and the measurement of their relative conductance as a function of H<SUB>2</SUB>O<SUB>2</SUB> concentrations. We further investigated the sensing mechanism by Fourier transform infrared (FTIR) spectroscopy and field-effect transistor measurements (FET). We propose here that the response to H<SUB>2</SUB>O<SUB>2</SUB> arises from the oxidation of EGCG in the composite. These findings suggest that SWNT/green tea composite has a great potential for developing simple resistivity-based sensors.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2010/ancac3.2010.4.issue-11/nn100988t/production/images/medium/nn-2010-00988t_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn100988t'>ACS Electronic Supporting Info</A></P>
Predictors and outcomes of laparoscopic nephrectomy in autosomal dominant polycystic kidney disease
Kenneth Chen,Yu Guang Tan,Darren Tan,Gregory Pek,Hong Hong Huang,Soon Phang Allen Sim 대한비뇨의학회 2018 Investigative and Clinical Urology Vol.59 No.4
Purpose: Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease, and 20% of patients eventually require nephrectomies due to compressive symptoms or renal-related complications. Traditionally, nephrectomies were performed via the open approach in view of space constraints. We evaluate our institution's outcomes for laparoscopic nephrectomy (LN) for ADPKD. Materials and Methods: We retrospectively reviewed 33 patients with ADPKD who underwent nephrectomies from November 2005 to December 2016 at a tertiary institution. Preoperative kidney volume was calculated via the ellipsoid method by using computed tomography scan. Results: The median age was 51.0 years (interquartile range [IQR], 44.5–56.0 years). Sixteen patients (48.5%) underwent open nephrectomy (ON), 15 patients (45.5%) had LNs, and 2 patients (6.1%) had laparoscopic converted to ON due to dense adhesions. Thirteen patients had bilateral while 18 patients had unilateral nephrectomies. Median kidney volume in the open group was 1,042 cm3 (IQR, 753–2,365 cm3) versus 899 cm3 (IQR, 482–1,914 cm3) in the laparoscopy group and did not differ significantly. The operative time was comparable between both groups. Patients who underwent LN had lesser blood loss (350 mL vs. 650 mL; 95% confidence interval [CI], 1.822–3.533; p=0.016) and shorter length of hospital stay (4.0 days vs. 6.5 days; 95% CI, 1.445–5.755; p=0.001) compared to patients who underwent ON. Both groups had similar low morbidity rate and no mortality.
Are Efficient and Inefficient Farms Heterogeneous? Evidence from Kansas Farms
김영준,Bowen Chen,Allen M. Featherstone,Dustin L. Pendell 한국농업경제학회 2023 農業經濟硏究 Vol.64 No.1
Most of the previous literature on efficiency assumes that efficient and inefficient farms are homogeneous in production, even though they may have different strategies to increase efficiency. Exploiting Super Data envelopment analysis (DEA) and quantile regression, this study examines the sources of efficiency with particular consideration of the heterogeneity between efficient and inefficient farms using a farm-level dataset. The results show that an increase in some farm characteristics, such as the number of beef cows, percentage of income from beef cows, and percentage of acres owned, affects efficiency in different ways for efficient and inefficient farms. These results imply that efficient and inefficient farms are heterogeneous in terms of how farm characteristics affect efficiency.
Xiongyu Luo,Muxuan Yang,Jinyu Bu,Tiantong Chen,Allen Y. Yi,Weinan Xu 한국고분자학회 2023 Macromolecular Research Vol.31 No.8
The integration of two or more types of metal oxides in the same nanostructures leads to several unique characteristics including tunable optical properties and band gap, enhanced catalytic property and stability. However, current approaches for the generation of those mixed metal oxides are predominantly based on bottom-up synthesis, which have limitations in fabricating precise nanostructures with monodispersed size and shape, and low compatibility with lithography-based micro-/nanofabrication processes. Here, we report a new approach for the precise fabrication of nanostructured mixed metal oxides (NMMOs) by the integration of soft nanoimprinting and sol–gel synthesis. The hybrid ink for nanoimprinting is composed of metal–organic compound and metal oxide colloidal nanoparticles of different metal species, after nanoimprinting, sol–gel reaction, and calcination, NMMOs with well-defined size and geometry are successfully obtained. The morphology, size, composition, and crystalline structure of the NMMOs are systematically tuned and studied, their potential application in photocatalysis is also investigated.
Endovascular Strategies in the Management of Acute Limb Ischemia
Benjamin Lind,Omar Morcos,Hector Ferral,Allen Chen,Thomas Aquisto,Stephen Lee,Cheong Jun Lee 대한혈관외과학회 2019 Vascular Specialist International Vol.35 No.1
Acute limb ischemia (ALI) represents one of the most common emergent scenarios encountered by a vascular specialist. Despite expedient revascularization, high rates of limb loss are reported along with high mortality rates which are second only to ruptured abdominal aortic aneurysms. Surgical revascularization is stan-dard of care. Endovascular techniques as an alternative have emerged to be appro-priate first line therapy when addressing the threatened limb. We review the etiol-ogy and classification of ALI and current endovascular techniques and evidence to date in the management of patients acutely presenting with extremity ischemia.
CHARGE TRANSPORT THROUGH CARBON NANOTUBE OR FULLERENE–MOLECULE–SILICON JUNCTIONS
FU-REN F. FAN,BO CHEN,AUSTEN K. FLATT,JAMES M. TOUR,ALLEN J. BARD 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2007 NANO Vol.2 No.5
We report here the current–voltage (i–V) characteristics of several (n++-Si/MNOPE/C60/Pt-tip) or (n++-Si/MNOPE/SWCNT/Pt-tip) junctions, where MNOPE = 2'-mononitro-4, 4'-bis(phenylethynyl)-1-phenylenediazonium and SWCNT = single wall carbon nanotube. A layer of C60 or SWCNT-derivatized MNOPE has strong effect on the i–V behavior of the junctions, including rectification, negative differential resistance (NDR) and switching behaviors. The i–V curve of a grafted molecular monolayer (GMM) of MNOPE atop n++-Si shows NDR behavior, whereas those of C60- and SWCNT-derivatized GMMs of MNOPE on n++-Si show strong rectifying behavior with opposite rectification polarities. With C60, larger currents were found with negative tip bias, while with SWCNT, the forward top bias was positive. Because C60 tends to be a good electron acceptor and SWCNTs tend to be good electron donors, they show different i–V behavior, as observed. Some of the (n++-Si/MNOPE/SWCNT/Pt-tip) junctions also show reversible bistable switching behavior.
Robertson, Alex W.,Lin, Yung-Chang,Wang, Shanshan,Sawada, Hidetaka,Allen, Christopher S.,Chen, Qu,Lee, Sungwoo,Lee, Gun-Do,Lee, Joohee,Han, Seungwu,Yoon, Euijoon,Kirkland, Angus I.,Kim, Heeyeon,Suenag American Chemical Society 2016 ACS NANO Vol.10 No.11
<P>Dopants in two-dimensional dichalcogenides have a significant role in affecting electronic, mechanical, and interfacial properties. Controllable doping is desired for the intentional modification of such properties to enhance performance; however, unwanted defects and impurity dopants also have a detrimental impact, as often found for chemical vapor deposition (CVD) grown films. The reliable identification, and subsequent characterization, of dopants is therefore of significant importance. Here, we show that Cr and V impurity atoms are found in CVD grown MoS2 monolayer 2D crystals as single atom substitutional dopants in place of Mo. We attribute these impurities to trace elements present in the MoO3 CVD precursor. Simultaneous annular dark field scanning transmission electron microscopy (ADF-STEM) and electron energy loss spectroscopy (EELS) is used to map the location of metal atom substitutions of Cr and V in MoS2 monolayers with single atom precision. The Cr and V are stable under electron irradiation at 60 to 80 kV, when incorporated into line defects, and when heated to elevated temperatures. The combined ADF-STEM and EELS differentiates these Cr and V dopants from other similar contrast defect structures, such as 2S self-interstitials at the Mo site, preventing misidentification. Density functional theory calculations reveal that the presence of Cr or V causes changes to the density of states, indicating doping of the MoS2 material. These transferred impurities could help explain the presence of trapped charges in CVD prepared MoS2.</P>
Tuning the optical and electrical properties of MoS<sub>2</sub> by selective Ag photo-reduction
Kim, Eunpa,Lee, Yoonkyung,Ko, Changhyun,Park, Yunjeong,Yeo, Junyeob,Chen, Yabin,Choe, Hwan Sung,Allen, Frances I.,Rho, Junsuk,Tongay, Sefaattin,Wu, Junqiao,Kim, Kyunghoon,Grigoropoulos, Costas P. American Institute of Physics 2018 APPLIED PHYSICS LETTERS Vol.113 No.1