5,245 research outputs found
Dynamic Analysis of X-ray Angiography for Image-Guided Coronary Interventions
Percutaneous coronary intervention (PCI) is a minimally-invasive procedure for treating patients with coronary artery disease. PCI is typically performed with image guidance using X-ray angiograms (XA) in which coronary arter
A Microcantilever-based Gas Flow Sensor for Flow Rate and Direction Detection
The purpose of this paper is to apply characteristics of residual stress that
causes cantilever beams to bend for manufacturing a micro-structured gas flow
sensor. This study uses a silicon wafer deposited silicon nitride layers,
reassembled the gas flow sensor with four cantilever beams that perpendicular
to each other and manufactured piezoresistive structure on each
micro-cantilever by MEMS technologies, respectively. When the cantilever beams
are formed after etching the silicon wafer, it bends up a little due to the
released residual stress induced in the previous fabrication process. As air
flows through the sensor upstream and downstream beam deformation was made,
thus the airflow direction can be determined through comparing the resistance
variation between different cantilever beams. The flow rate can also be
measured by calculating the total resistance variations on the four
cantilevers.Comment: Submitted on behalf of EDA Publishing Association
(http://irevues.inist.fr/handle/2042/16838
Chandra Observation of NGC 1559: Eight Ultraluminous X-ray Sources Including a Compact Binary Candidate
Despite the 30-year history of ultra-luminous X-ray sources (ULXs) studies,
issues like the majority of their physical natures (i.e., neutron stars,
stellar-mass black holes, or intermediate black holes) as well as the accretion
mechanisms are still under debate. Expanding the ULX sample size in the
literature is clearly a way to help. To this end, we investigated the X-ray
source population, ULXs in particular, in the barred spiral galaxy NGC 1559
using a Chandra observation made in 2016. In this 45-ks exposure, 33 X-ray
point sources were detected within the 2.'7 isophotal radius of the galaxy.
Among them, 8 ULXs were identified with the criterion of the X-ray luminosity
erg s (0.3-7~keV). Both X-ray light curves and spectra of
all the sources were examined. Except for some low-count spectra that only
provide ambiguous spectral fitting results, all the X-ray sources were
basically spectrally hard and therefore likely have non-thermal origins. While
no strong X-ray variability was present in most of the sources owing to the
relatively short exposure of the observation, we found an intriguing ULX, named
X-24, exhibiting a periodicity of 7500s with a detection significance of
2.7. We speculate that it is the orbital period of the system.
Roche-lobe over flow and Roche limit are consistent with the speculation. Thus,
we suggest that X-24 may be the one of the rare compact binary ULXs, and hence,
a good candidate as a stellar-mass black hole.Comment: Accepted for publication in Ap
Suppression of Ongoing Experimental Arthritis by a Chinese Herbal Formula (Huo-Luo-Xiao-Ling Dan) Involves Changes in Antigen-Induced Immunological and Biochemical Mediators of Inflammation
Rheumatoid arthritis (RA) is one of the major autoimmune diseases of global prevalence. The use of the anti-inflammatory drugs for the treatment of RA is associated with severe adverse reactions and toxicity. This limitation has necessitated the search for novel therapeutic products. We report here a traditional Chinese medicine-based herbal formula, Huo luo xiao ling dan (HLXL), which has potent antiarthritic activity as validated in the rat adjuvant-induced arthritis (AA) model. HLXL (2.3 g/Kg) was fed to Lewis (RT.11) rats daily by gavage beginning at the onset of arthritis and then continued through the observation period. HLXL inhibited the severity of ongoing AA. This suppression of arthritis was associated with significant alterations in the T cell proliferative and cytokine responses as well as the antibody response against the disease-related antigen, mycobacterial heat-shock protein 65 (Bhsp65). There was a reduction in the level of the proinflammatory cytokines IL-17 and IL-1β but enhancement of the anti-inflammatory cytokine IL-10 level. In addition, there was inhibition of both the anti-Bhsp65 antibody response and the serum level of nitric oxide. Thus, HLXL is a promising CAM modality for further testing in RA patients
Effective DBHF Method for Asymmetric Nuclear Matter and Finite Nuclei
A new decomposition of the Dirac structure of nucleon self-energies in the
Dirac Brueckner-Hartree-Fock (DBHF) approach is adopted to investigate the
equation of state for asymmetric nuclear matter. The effective coupling
constants of , , and mesons with a density
dependence in the relativistic mean field approach are deduced by reproducing
the nucleon self-energy resulting from the DBHF at each density for symmetric
and asymmetric nuclear matter. With these couplings the properties of finite
nuclei are investigated. The agreement of charge radii and binding energies of
finite nuclei with the experimental data are improved simultaneously in
comparison with the projection method. It seems that the properties of finite
nuclei are sensitive to the scheme used for the DBHF self-energy extraction. We
may conclude that the properties of the asymmetric nuclear matter and finite
nuclei could be well described by the new decomposition approach of the G
matrix.Comment: 16 pages, 5 figure
Ratio of shear viscosity to entropy density in multifragmentation of Au + Au
The ratio of the shear viscosity () to entropy density () for the
intermediate energy heavy-ion collisions has been calculated by using the
Green-Kubo method in the framework of the quantum molecular dynamics model. The
theoretical curve of as a function of the incident energy for the
head-on Au+Au collisions displays that a minimum region of has been
approached at higher incident energies, where the minimum value is
about 7 times Kovtun-Son- Starinets (KSS) bound (1/4). We argue that the
onset of minimum region at higher incident energies corresponds to the
nuclear liquid gas phase transition in nuclear multifragmentation.Comment: 6 pages, 8 figure
PPNet: Identifying functional association networks by phylogenetic profiling of prokaryotic genomes
Identification of microbial functional association networks allows interpretation of biological phenomena and a greater understanding of the molecular basis of pathogenicity and also underpins the formulation of control measures. Here, we describe PPNet, a tool that uses genome information and analysis of phylogenetic profiles with binary similarity and distance measures to derive large-scale bacterial gene association networks of a single species. As an exemplar, we have derived a functional association network in the pig pathogen Streptococcus suis using 81 binary similarity and dissimilarity measures which demonstrates excellent performance based on the area under the receiver operating characteristic (AUROC), the area under the precision-recall (AUPR), and a derived overall scoring method. Selected network associations were validated experimentally by using bacterial two-hybrid experiments. We conclude that PPNet, a publicly available (https://github.com/liyangjie/PPNet), can be used to construct microbial association networks from easily acquired genome-scale data. IMPORTANCE This study developed PPNet, the first tool that can be used to infer large-scale bacterial functional association networks of a single species. PPNet includes a method for assigning the uniqueness of a bacterial strain using the average nucleotide identity and the average nucleotide coverage. PPNet collected 81 binary similarity and distance measures for phylogenetic profiling and then evaluated and divided them into four groups. PPNet can effectively capture gene networks that are functionally related to phenotype from publicly prokaryotic genomes, as well as provide valuable results for downstream analysis and experiment testing
H2S Donor, S-Propargyl-Cysteine, Increases CSE in SGC-7901 and Cancer-Induced Mice: Evidence for a Novel Anti-Cancer Effect of Endogenous H2S?
Background: S-propargyl-cysteine (SPRC), an H2S donor, is a structural analogue of S-allycysteine (SAC). It was investigated for its potential anti-cancer effect on SGC-7901 gastric cancer cells and the possible mechanisms that may be involved. Methods and Findings: SPRC treatment significantly decreased cell viability, suppressed the proliferation and migration of SPRC-7901 gastric cancer cells, was pro-apoptotic as well as caused cell cycle arrest at the G 1/S phase. In an in vivo study, intra-peritoneal injection of 50 mg/kg and 100 mg/kg of SPRC significantly reduced tumor weights and tumor volumes of gastric cancer implants in nude mice, with a tumor growth inhibition rate of 40–75%. SPRC also induced a pro-apoptotic effect in cancer tissues and elevated the expressions of p53 and Bax in tumors and cells. SPRC treatment also increased protein expression of cystathione-c-lyase (CSE) in cells and tumors, and elevated H 2S levels in cell culture media, plasma and tumoral CSE activity of gastric cancer-induced nude mice by 2, 2.3 and 1.4 fold, respectively. Most of the anti-cancer functions of SPRC on cells and tumors were significantly suppressed by PAG, an inhibitor of CSE activity. Conclusions: Taken together, the results of our study provide insights into a novel anti-cancer effect of H2S as well as o
Ultrafast and Large Third-order Nonlinear Optical Properties of CdS Nanocrystals in Polymeric Film
We report the ultrafast and large third-order nonlinear optical properties of
CdS nanocrystals (NCs) embedded in a polymeric film. The CdS NCs of 2-nm radius
are synthesized by an ion exchange method and highly concentrated in the two
layers near the surfaces of the polymeric film. The two-photon absorption
coefficient and the optical Kerr coefficient are measured with laser pulses of
250-fs duration at 800-nm wavelength. The one-photon and two-photon figures of
merit are determined to be 3.1 and 1.3, respectively, at irradiance of 2
GW/cm2. The observed nonlinearities have a recovery time of ~ 1 ps. The
two-photon-generated free carrier effects have also been observed and
discussed. These results demonstrate that CdS NCs embedded in polymeric film
are a promising candidate for optical switching applications.Comment: 18 pages, 4 figure
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