1,730 research outputs found
Observation of chiral quantum-Hall edge states in graphene
In this study, we determined the chiral direction of the quantum-Hall (QH)
edge states in graphene by adopting simple two-terminal conductance
measurements while grounding different edge positions of the sample. The edge
state with a smaller filling factor is found to more strongly interact with the
electric contacts. This simple method can be conveniently used to investigate
the chirality of the QH edge state with zero filling factor in graphene, which
is important to understand the symmetry breaking sequence in high magnetic
fields (25 T).Comment: 3 pages, 3 figures. Appeared in AP
Dependence of quantum-Hall conductance on the edge-state equilibration position in a bipolar graphene sheet
By using four-terminal configurations, we investigated the dependence of
longitudinal and diagonal resistances of a graphene p-n interface on the
quantum-Hall edge-state equilibration position. The resistance of a p-n device
in our four-terminal scheme is asymmetric with respect to the zero point where
the filling factor () of the entire graphene vanishes. This resistance
asymmetry is caused by the chiral-direction-dependent change of the
equilibration position and leads to a deeper insight into the equilibration
process of the quantum-Hall edge states in a bipolar graphene system.Comment: 5 pages, 4 figures, will be published in PR
What Questions do People Ask on a Human Papillomavirus Website? A Comparative Analysis of Public and Private Questions
Objective: In 2004, we launched the question and answer (Q&A) section on a human papillomavirus (HPV) website (www.hpvkorea.org) that provides ample and regularly updated information about HPV. The purpose of this study is to collect data pertaining to questions posed on this website about HPV and its related diseases and analyze the type of questions and frequency before and after introduction of HPV vaccine in Korea. Using these results, we intend to determine the clinical and practical implications for doctors treating HPV and for HPV website providers
Thermoelectric Transport of Massive Dirac Fermions in Bilayer Graphene
Thermoelectric power (TEP) is measured in bilayer graphene for various
temperatures and charge-carrier densities. At low temperatures, measured TEP
well follows the semiclassical Mott formula with a hyperbolic dispersion
relation. TEP for a high carrier density shows a linear temperature dependence,
which demonstrates a weak electron-phonon interaction in the bilayer graphene.
For a low carrier density, a deviation from the Mott relation is observed at
high temperatures and is attributed to the low Fermi temperature in the bilayer
graphene. Oscillating TEP and the Nernst effect for varying carrier density,
observed in a high magnetic field, are qualitatively explained by the two
dimensionality of the system.Comment: published versio
3D QSAR Pharmacophore Modeling, in Silico Screening, and Density Functional Theory (DFT) Approaches for Identification of Human Chymase Inhibitors
Human chymase is a very important target for the treatment of cardiovascular diseases. Using a series of theoretical methods like pharmacophore modeling, database screening, molecular docking and Density Functional Theory (DFT) calculations, an investigation for identification of novel chymase inhibitors, and to specify the key factors crucial for the binding and interaction between chymase and inhibitors is performed. A highly correlating (r = 0.942) pharmacophore model (Hypo1) with two hydrogen bond acceptors, and three hydrophobic aromatic features is generated. After successfully validating “Hypo1”, it is further applied in database screening. Hit compounds are subjected to various drug-like filtrations and molecular docking studies. Finally, three structurally diverse compounds with high GOLD fitness scores and interactions with key active site amino acids are identified as potent chymase hits. Moreover, DFT study is performed which confirms very clear trends between electronic properties and inhibitory activity (IC50) data thus successfully validating “Hypo1” by DFT method. Therefore, this research exertion can be helpful in the development of new potent hits for chymase. In addition, the combinational use of docking, orbital energies and molecular electrostatic potential analysis is also demonstrated as a good endeavor to gain an insight into the interaction between chymase and inhibitors
Is an Industrial Policy Possible in China?: The Case of the Automobile Industry
This paper first defines industrial policy as entry control and capacity reorganization, and then evaluates the effectiveness of industrial policy in the automobile sector in China. It argues that the industrial policies declared in 87 and 94 in China were not implemented successfully enough to control new entries nor to reorganize capacity among the incumbent companies. Consequently, the industrial organization of the automobile sector was highly fragmented. Concerning the cause of entry control failure, this paper examines the incentive structure of Chinese local governments that exercised de facto property rights over the companies in their jurisdiction throughout the reform period. It shows that local governments have strong incentives to ward off the central governments entry control, and that local governments were strong enough to resist the centers order, backed up by their fiscal and administrative capacity. To explain the causes of capacity reorganization failure, this paper looks at the cases of the First Auto Works groups M&As, and argues that these M&As did not lead to effective capacity reorganization within the group. The paper concludes that industrial policy has failed in China, and that the central government finds it difficult to conduct effective industrial policy given the strength of local governments. The recent and future development of the Chinese automobile industry seems to be driven by market forces rather than by discretionary industrial policy
Inelastic scattering in a monolayer graphene sheet; a weak-localization study
Charge carriers in a graphene sheet, a single layer of graphite, exhibit much
distinctive characteristics to those in other two-dimensional electronic
systems because of their chiral nature. In this report, we focus on the
observation of weak localization in a graphene sheet exfoliated from a piece of
natural graphite and nano-patterned into a Hall-bar geometry. Much stronger
chiral-symmetry-breaking elastic intervalley scattering in our graphene sheet
restores the conventional weak localization. The resulting carrier-density and
temperature dependence of the phase coherence length reveal that the
electron-electron interaction including a direct Coulomb interaction is the
main inelastic scattering factor while electron-hole puddles enhance the
inelastic scattering near the Dirac point.Comment: 12 pages, 3 figures, submitted to PR
Quantum Hall resistances of multiterminal top-gated graphene device
Four-terminal resistances, both longitudinal and diagonal, of a locally gated
graphene device are measured in the quantum-Hall (QH) regime. In sharp
distinction from previous two-terminal studies [J. R. Williams \textit{et al.},
Science {\bf 317}, 638 (2007); B. \"{O}zyilmaz \textit{et al.}, Phys. Rev.
Lett. {\bf 99}, 166804 (2007)], asymmetric QH resistances are observed, which
provide information on reflection as well as transmission of the QH edge
states. Most quantized values of resistances are well analyzed by the
assumption that all edge states are equally populated. Contrary to the
expectation, however, a 5/2 transmission of the edge states is also found,
which may be caused by incomplete mode mixing and/or by the presence of
counter-propagating edge states. This four-terminal scheme can be conveniently
used to study the edge-state equilibration in locally gated graphene devices as
well as mono- and multi-layer graphene hybrid structures.Comment: 6 pages, 4 figures. Typos and equations (2-4) have been corrected.
Phys. Rev. B 79, 195327 (2009
Benign metastasizing leiomyoma of the lung
Benign leiomyomas of the uterus are uncommonly found in association with benign smooth muscle tumors beyond the confines of the uterus. Benign metastasizing leiomyoma (BML) is a rare disease in which the lung is described to be the most afflicted extrauterine organ. We present a brief review of the literature, along with case reports for four patients who were followed up after resection of a pulmonary lesion or after pathological confirmation by biopsy. The clinical course of BML varies from chronic asymptomatic appearance to rapid progression, leading to respiratory failure and death. Our BML patients did not complain of pulmonary symptoms, such as cough, dyspnea, or chest tightness. Pathology revealed benign leiomyomas with no atypia and mitotic activity <5 per 10 high-power field. Immunohistochemical staining was positive for actin and desmin. A standard treatment for BML has not yet been established. Because of the hormone-sensitive characteristics of BML, treatments are based on hormonal manipulation along with either surgical or medical oophorectomy. Benign metastasizing leiomyoma can be observed in postmenopausal women. We observed four patients who did not receive adjuvant hormonal therapy because they were postmenopausal or perimenopausal. All patients are still healthy and show no evidence of recurrence or progression of the disease
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