2,998 research outputs found
Effects of Geometrical Symmetry on the Vortex Nucleation and Penetration in Mesoscopic Superconductors
We investigate how the geometrical symmetry affects the penetration and
arrangement of vortices in mesoscopic superconductors using self-consistent
Bogoliubov-de Gennes equations. We find that the entrance of the vortex happens
when the current density at the hot spots reaches the depairing current
density. Through determining the spatial distribution of hot spots, the
geometrical symmetry of the superconducting sample influences the nucleation
and entrance of vortices. Our results propose one possible experimental
approach to control and manipulate the quantum states of mesoscopic
superconductors with their topological geometries, and they can be easily
generalized to the confined superfluids and Bose-Einstein condensates
Automatic cell segmentation by adaptive thresholding (ACSAT) for large-scale calcium imaging datasets
Advances in calcium imaging have made it possible to record from an increasingly larger number of neurons simultaneously. Neuroscientists can now routinely image hundreds to thousands of individual neurons. An emerging technical challenge that parallels the advancement in imaging a large number of individual neurons is the processing of correspondingly large datasets. One important step is the identification of individual neurons. Traditional methods rely mainly on manual or semimanual inspection, which cannot be scaled for processing large datasets. To address this challenge, we focused on developing an automated segmentation method, which we refer to as automated cell segmentation by adaptive thresholding (ACSAT). ACSAT works with a time-collapsed image and includes an iterative procedure that automatically calculates global and local threshold values during successive iterations based on the distribution of image pixel intensities. Thus, the algorithm is capable of handling variations in morphological details and in fluorescence intensities in different calcium imaging datasets. In this paper, we demonstrate the utility of ACSAT by testing it on 500 simulated datasets, two wide-field hippocampus datasets, a wide-field striatum dataset, a wide-field cell culture dataset, and a two-photon hippocampus dataset. For the simulated datasets with truth, ACSAT achieved >80% recall and precision when the signal-to-noise ratio was no less than âŒ24 dB.DP2 NS082126 - NINDS NIH HHSPublished versio
1,2-Bis(4-nitroÂbenzÂyl)diselane
The title compound, C14H12N2O4Se2, is not chiral, but the molÂecules assume a chiral conformation in the solid state and crystallize as an aggregate. The central CâSeâSeâC torsion angle is 90.4â
(2)°, while the two SeâSeâCâC fragments assume gauche conformations with values of â59.4â
(5) and 67.5â
(4)°. The dihedral angle between the two benzene rings is 80.74â
(14)°
Two-photon interference with two independent pseudo-thermal sources
The nature of two-photon interference is a subject that has aroused renewed
interest in recent years and is still under debate. In this paper we report the
first observation of two-photon interference with independent pseudo-thermal
sources in which sub-wavelength interference is observed. The phenomenon may be
described in terms of the classical statistical distribution of the two sources
and their optical transfer functions.Comment: Phys. Rev. A 74, 053807 (2006
Protective Effect of Anthocyanins Extract from Blueberry on TNBS-Induced IBD Model of Mice
This study was carried out to evaluate the protective effect of anthocyanins extract of blueberry on trinitrobenzene sulfonic acid (TNBS)-induced inflammatory bowel disease (IBD) model of mice. The study employed female C57BL/6 mice (n = 50), and colitis was induced by intracolonic injection of 0.5âmg of TNBS dissolved in 50% ethanolâphosphate buffered solution. The mice were divided into five groups (n = 10): vehicle, TNBS control and anthocyanins groups that received different doses of anthocyanins extract (10, 20 and 40âmgâkgâ1) daily for 6 days. Both increase in body weight and diarrhea symptoms were monitored each day. After 6 days, the animals were killed, and the following parameters were assessed: colon length, morphological score, histological score and biochemical assay (NO, myeloperoxidase (MPO), interleukin (IL)-12, IL-10, tumor necrosis factor (TNF)-α and interferon (IFN)-Îł). The results showed that the anthocyanins extract of blueberry rendered strong protection against TNBS-induced colonic damage at a dosage of 40âmgâkgâ1. When compared with the control, anthocyanins extract significantly prevented loss of body weight and ameliorated the scores of diarrhea, morphology and histology. Treatment with anthocyanins extract restored IL-10 excretion, as well as caused reduction in the levels of NO, MPO, IL-12, TNF-α and IFN-Îł. Our research revealed the protective effect of anthocyanins extract from blueberry on TNBS-induced experimental colitis in mice, as well as examined whether high levels of dietary blueberries would lower the risk or have protective effects on human IBD, which may require further investigation
Correlated two-photon imaging with true thermal light
We report the first experimental demonstration of two-photon correlated
imaging with true thermal light from a hollow cathode lamp. The coherence time
of the source is much shorter than that of previous experiments using random
scattered light from a laser. A two-pinhole mask was used as object, and the
corresponding thin lens equation was well satisfied. Since thermal light
sources are easier to obtain and measure than entangled light it is conceivable
that they may be used in special imaging applications.Comment: 3 pages, 5 figures, accepted by Optics Letter
Depletion of OLFM4 gene inhibits cell growth and increases sensitization to hydrogen peroxide and tumor necrosis factor-alpha induced-apoptosis in gastric cancer cells
<p>Abstract</p> <p>Background</p> <p>Human olfactomedin 4 (OLFM4) gene is a secreted glycoprotein more commonly known as the anti-apoptotic molecule GW112. OLFM4 is found to be frequently up-regulated in many types of human tumors including gastric cancer and it was believed to play significant role in the progression of gastric cancer. Although the function of OLFM4 has been indicated in many studies, recent evidence strongly suggests a cell or tissue type-dependent role of OLFM4 in cell growth and apoptosis. The aim of this study is to examine the role of gastric cancer-specific expression of OLFM4 in cell growth and apoptosis resistance.</p> <p>Methods</p> <p>OLFM4 expression was eliminated by RNA interference in SGC-7901 and MKN45 cells. Cell proliferation, anchorage-independent growth, cell cycle and apoptosis were characterized in vitro. Tumorigenicity was analyzed in vivo. The apoptosis and caspase-3 activation in response to hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) or tumor necrosis factor-alpha (TNF α) were assessed in the presence or absence of caspase inhibitor Z-VAD-fmk.</p> <p>Results</p> <p>The elimination of OLFM4 protein by RNA interference in SGC-7901 and MKN45 cells significantly inhibits tumorigenicity both in vitro and in vivo by induction of cell G1 arrest (all P < 0.01). OLFM4 knockdown did not trigger obvious cell apoptosis but increased H<sub>2</sub>O<sub>2 </sub>or TNF α-induced apoptosis and caspase-3 activity (all P < 0.01). Treatment of Z-VAD-fmk attenuated caspase-3 activity and significantly reversed the H<sub>2</sub>O<sub>2 </sub>or TNF α-induced apoptosis in OLFM4 knockdown cells (all P < 0.01).</p> <p>Conclusion</p> <p>Our study suggests that depletion of OLFM4 significantly inhibits tumorigenicity of the gastric cancer SGC-7901 and MKN45 cells. Blocking OLFM4 expression can sensitize gastric cancer cells to H<sub>2</sub>O<sub>2 </sub>or TNF α treatment by increasing caspase-3 dependent apoptosis. A combination strategy based on OLFM4 inhibition and anticancer drugs treatment may provide therapeutic potential in gastric cancer intervention.</p
Two-photon interference with true thermal light
Two-photon interference and "ghost" imaging with entangled light have
attracted much attention since the last century because of the novel features
such as non-locality and sub-wavelength effect. Recently, it has been found
that pseudo-thermal light can mimic certain effects of entangled light. We
report here the first observation of two-photon interference with true thermal
light.Comment: 4 pages, 5 figures, PRA72, 043805 (2005
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