-
[show abstract]
[hide abstract]
ABSTRACT: Divalproex sodium is an antiepileptic drug. Hepatotoxicity is one of the most common side effects induced by divalproex sodium. Impaired fatty acid metabolism is considered to play an important role in the drug-induced hepatotoxicity. The sterol regulatory element-binding protein 1c (SREBP-1c) and peroxisome proliferator-activated receptor α (PPARα) are two key transcription factors involved, respectively, in fatty acid synthesis and degradation in liver. In the present study, we investigated the hepatotoxicity induced by divalproex sodium and its potential mechanism. The results indicated that divalproex sodium significantly decreased the cell viability and increased lactate dehydrogenase leakage in hepatocytes. The activities of alanine aminotransferase and aspartate transaminase were increased in hepatocytes treated with divalproex sodium. Furthermore, divalproex sodium activated SREBP-1c and increased the mRNA expressions of acetyl-CoA carboxylase 1, fatty acid synthase and stearoyl-CoA desaturase 1. Divalproex sodium also inhibited PPARα and decreased the messenger RNA expressions of 3-hydroxy-3-methylglutaryl-CoA synthase 2 and carnitine palmitoyltransferase 1A. These results suggest that the hepatotoxicity induced by divalproex sodium may be related with fatty acid synthesis and degradation mediated by SREBP-1c and PPARα in hepatocytes.
Human & Experimental Toxicology 04/2012; · 1.31 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Automated analysis of imaged histopathology specimens could potentially provide support for improved reliability in detection and classification in a range of investigative and clinical cancer applications. Automated segmentation of cells in the digitized tissue microarray (TMA) is often the prerequisite for quantitative analysis. However overlapping cells usually bring significant challenges for traditional segmentation algorithms.
In this paper, we propose a novel, automatic algorithm to separate overlapping cells in stained histology specimens acquired using bright-field RGB imaging.
It starts by systematically identifying salient regions of interest throughout the image based upon their underlying visual content. The segmentation algorithm subsequently performs a quick, voting based seed detection. Finally, the contour of each cell is obtained using a repulsive level set deformable model using the seeds generated in the previous step. We compared the experimental results with the most current literature, and the pixel wise accuracy between human experts' annotation and those generated using the automatic segmentation algorithm.
The method is tested with 100 image patches which contain more than 1000 overlapping cells. The overall precision and recall of the developed algorithm is 90% and 78%, respectively. We also implement the algorithm on GPU. The parallel implementation is 22 times faster than its C/C++ sequential implementation.
The proposed segmentation algorithm can accurately detect and effectively separate each of the overlapping cells. GPU is proven to be an efficient parallel platform for overlapping cell segmentation.
Methods of Information in Medicine 04/2012; 51(3):260-7. · 1.53 Impact Factor
-
Ref. No: U.S. Patent No. 8,147,985, Year: 04/2012
-
J. A. Banks,
T. Nishiyama,
M. Hasebe,
J. L. Bowman,
M. Gribskov,
C. Depamphilis,
V. A. Albert,
N. Aono,
T. Aoyama,
B. A. Ambrose, [......],
U. Hellsten,
D. Loque,
R. Otillar,
A. Salamov,
J. Schmutz,
H. Shapiro,
E. Lindquist,
S. Lucas,
D. Rokhsar,
I. V. Grigoriev
[show abstract]
[hide abstract]
ABSTRACT: Vascular plants appeared ~410 million years ago, then diverged into several lineages, of which only two survive: the euphyllophytes(ferns and seed plants) and the lycophytes. Here, we report the genome sequence of the lycophyte Selaginella moellendorffii (Selaginella), the first nonseed vascular plant genome reported. By comparing gene content in evolutionary diverse taxa, we found that the transition from a gametophyte- to sporophyte-dominated life cycle required far fewer new genes than the transition from a nonseed vascular to a flowering plant, while secondary metabolic genes expanded extensively and in parallel in the lycophyte and angiosperm lineages. Selaginella differs in posttranscriptional gene regulation, including small RNA regulation of repetitive elements, an absence of the tasiRNA pathway and extensive RNA editing of organellar genes.
Science. 01/2011; 5:5.
-
[show abstract]
[hide abstract]
ABSTRACT: a b s t r a c t Flow behavior and microstructures of superalloy 718 were investigated by hot compression tests per-formed at temperatures ranging from 950 to 1100 • C with strain rates of 10 −3 to 1 s −1 . The dependence of the peak stress on deformation temperature and strain rate can be expressed by a hyperbolic-sine type equation. The activation energy for superalloy 718 is determined to be 443.2 kJ mol −1 . A power exponent relationship between the peak strain and the Z parameter is obtained. Microstructure analysis shows that the dynamically recrystallized grain size is inversely proportional to the Z parameter. The nucleation mechanisms of DRX are closely related to the value of Z parameter. Under low Z conditions, DRX nucleation and development are mainly assisted by the formation of twins near the original grain boundaries.
Materials Science and Engineering A. 01/2008; 497:479-486.
-
[show abstract]
[hide abstract]
ABSTRACT: The undulator based beamline X13A at the National Synchrotron Light Source has been commissioned recently. The X13 undulator has an 8 cm period, and its first harmonic is in the energy range of 200–700 eV at the nominal ring energy of 2.5 GeV. The beamline uses horizontally deflecting optics. It consists of a SiC plane mirror, a water cooled entrance slit, a spherical grating, and two fixed exit slits. A flux of more than 10<sup>12</sup> photons/s at 450 eV has been measured at X13A with an aluminum‐oxide photodiode with a 200 μm entrance slit, a 500 μm exit slit, and a ring current of 242 mA. A VF 3 absorption spectrum recorded at X13A shows the monochromator resolving power is at least 1000 at ∼500 eV with 30 μm entrance and exit slits, in agreement with calculations. The X13A beamline will be used for x‐ray coherence studies, spectroscopy, and multilayer reflectivity measurements as well as for x‐ray instrumentation diagnostics. © 1995 American Institute of Physics.
Review of Scientific Instruments 03/1995; · 1.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We designed and built an intensity interferometer to characterize the spatial coherence of a soft x‐ray undulator beam. The beam source size and shape can be determined from the measured coherence function. The instrument is 400 mm long and is mounted on a standard 204‐mm diameter flange. This compact design is readily adaptable to other beamlines with sources of sufficient spectral brightness. Details of the interferometer design and performance are presented. We anticipate that when this technique is mature, it will provide a useful diagnostic for high brightness x‐ray beams. © 1995 American Institute of Physics.
Review of Scientific Instruments 03/1995; · 1.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This paper describes a technique for on-line signature verification using Hidden Markov Models (HMMs). Signatures are captured and digitized in real-time using a graphic tablet. For each signature a HMM is constructed using a set of sample signatures described by the normalized directional angle function of the distance along the signature trajectory. The Baum-Welch algorithm is used for both training and classification. Experimental results based on 496 signatures from 31 subjects are presented which show that HMM technique is very potential for signature verification.
Pattern Recognition. 01/1995;
-
[show abstract]
[hide abstract]
ABSTRACT: Deformation behavior and microstructure evolution of 7050 aluminum alloy were investigated by tensile tests conducted at different temperatures (340, 380, 420, and 460 °C) with different strain rates of 1.0 × 10−4, 1.0 × 10−3, 1.0 × 10−2 and 0.1 s−1. The results show that the stress level of the alloy can be presented by a Zener–Holloman parameter in a hyperbolic sine-type equation with the hot activation energy of 256.6 kJ/mol. Ductile transgranular fracture transforms progressively into ductile intergranular (or inter-subgranular) fracture with the decrease of Z value. At the same time, the soften mechanism of the alloy during high temperature deformation transforms from dynamic recovery to continuous dynamic recrystallization with decreasing Z value. The main deformation mechanism is usual slipping when the alloy was deformed at high Z value. Grain boundaries sliding takes part in deformation with low Z value. Grain boundaries migration plays the role with medium Z value.
Materials Science and Engineering: A.
-
[show abstract]
[hide abstract]
ABSTRACT: Some Fe-alloyed CoSb3 compounds (LayFe4−xCoxSb12, with x=1–3 and y=0–0.75) with/without rare-earth element filling with different average grain sizes (about 0.8, 3.9 and 6.7 μm) were prepared by hot pressing and their thermoelectric properties were measured from room temperature to 773 K. Grain size has an obvious effect on the electrical resistivity and Seebeck coefficient of the La-filled samples. The electrical resistivity decreases and the Seebeck coefficient increases with increasing grain size for the La-filled samples. However, the electrical resistivity and Seebeck coefficient of the unfilled samples are relatively independent of their grain sizes. Unlike binary CoSb3, lattice thermal conductivity of the samples is found to be insensitive to the grain size within the investigated range. Theoretical analysis shows that the effect of boundary scattering on the lattice thermal conductivity in these LayFe4−xCoxSb12 compounds is relatively weaker than that in CoSb3. For the La-filled skutterudite compound, the figure of merit (ZT) increases with grain size, indicating that a relatively large grain size yields good thermoelectric properties for these compounds.
Journal of Alloys and Compounds.
-
[show abstract]
[hide abstract]
ABSTRACT: This paper is concerned with the free vibration of skew sandwich plates composed of an orthotropic core and laminated facings. The p -Ritz method has been adopted for the analysis. The Ritz functions are formed from the product of mathematically complete polynomials and boundary equations raised to appropriate integer powers depending on the boundary conditions. The boundary equations ensure the satisfaction of the geometric boundary conditions a priori and facilitate the handling of any type of boundary conditions. For generality, better accuracy and ease in imposition of geometric boundary condition for the oblique edges, the Ritz formulation was non-dimensionalized and cast in the skew co-ordinates system. Since no vibration solutions are available for such skew sandwich plates, the validity, convergence and accuracy of the Ritz formulation were established by comparing with other researchers' vibration frequencies for various subset plate problems involving rectangular sandwich plates and skew laminated plates. The paper features extensive generic vibration frequencies of these skew sandwich plates for various aspect ratios and boundary conditions, lamination designs of facings, material properties of core and facings.
Journal of Sound and Vibration.
-
[show abstract]
[hide abstract]
ABSTRACT: Previously our laboratory showed that calcitonin gene-related peptide (CGRP) is released from perivascular nerves exposed to endotoxin or inflammatory mediators bradykinin and prostaglandins. CGRP contributes significantly to the vasodilation of inflammation and septic shock. Another potential action of CGRP is inhibition of vascular smooth muscle cell (VSMC) growth, which could serve to counterbalance the stimulatory effects of IL-1 and TNF on VSMC proliferation. VSMCs from rabbit and rat aorta (in the second and fifth passages) were plated at 100 000 cells/well in 24-well trays in 10% fetal bovine serum (FBS) for 24 h, incubated for an additional 24 h without FBS, and then exposed to 2.5% FBS for 24 h in the presence or absence of CGRP. 3H-thymidine incorporation was used to measure DNA synthesis and proliferation. CGRP caused significant inhibition of 3H-thymidine incorporation, which correlated with elevations of cAMP in both rat and rabbit aortic VSMCs. Interestingly, the responses of both the elevation of cAMP and the inhibition of DNA synthesis became larger in VSMCs with an increasing number of passages. The data suggest that the CGRP, released during vascular inflammation, may serve to inhibit the proliferation of VSMCs, thus limiting the growth of atheromatous lesions.
Neuropeptides.
-
Physica C-Superconductivity and Its Applications. 398(1-2):31-36.
-
[show abstract]
[hide abstract]
ABSTRACT: We are constructing an X-ray intensity interferometer and an undulator beamline to demonstrate intensity interferometry in the soft X-ray region. The 10-period X13 soft X-ray undulator at the National Synchrotron Light Source will provide the coherent flux; the X13A beamline will preserve the brightness of the X-ray beam and provide sufficient temporal coherence with a horizontally deflecting spherical grating monochromator. Using the interferometer, which consists of an array of small slits, a wedge-shaped beamsplitter and two fast microchannel plate detectors, we expect to measure the spatial coherence of the undulator beam and therefore the size of the source. The beamline design and the interferometry experiment are discussed.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
-
[show abstract]
[hide abstract]
ABSTRACT: We examined the effects of 4-aminopyridine (4-AP) on isolated horizontal (superficial, middle and deep) rat neocortical slices in order to study laminar synchronous network behavior directly. Application of 4-AP induced spontaneous synchronized activity in all of these types of slices. In middle and deep layer slices the activities were similar to those of coronal slices, consisting of periodic short- and long-duration discharges. In superficial slices distinct spontaneous rhythmic multiphasic burst discharges were induced.Ionotropic glutamate receptor antagonists blocked the 4-AP-induced synchronous activities in middle and deep layer slices, but those in superficial slices persisted. The GABAA receptor antagonist picrotoxin suppressed this spontaneous synchronous activity resistant to 3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (a NMDA receptor antagonist) and 6-cyano-7-nitroquinoxaline-2,3-dione (a non-NMDA receptor antagonist), in superficial slices, leaving small, slow spontaneous events. In superficial slices with intact excitatory amino acid transmission, picrotoxin attenuated the 4-AP-induced spontaneous synchronous discharges, even in this highly convulsant environment. By contrast, conventional coronal slices showed robust spontaneous epileptiform discharges under these circumstances. In intact coronal slices focal 4-AP application in superficial layers induced spontaneous inhibitory GABAergic events, while delivery into deep layers led to epileptiform discharges.From these results we conclude that: (1) 4-AP-induced population discharges are driven by glutamatergic transmission in middle and deep layer horizontal slices, and by GABAergic transmission in superficial layers; (2) only superficial layers are capable of supporting synchronized GABAergic activity independent of excitatory amino acid transmission; (3) superficial layers do not sustain epileptiform activity in the absence of deep layer neurons; and (4) synchronized superficial networks can inhibit deep layer neuronal activity.
Neuroscience.
-
[show abstract]
[hide abstract]
ABSTRACT: The La2/3Ca1/3MnO3 (LCMO, tm=300 Å)/YBa2Cu3O7−δ (YBCO, ts=20–500 Å) heterostructural bilayers are prepared by the rf magnetic sputtering technique on SrTiO3 (STO) substrate at high temperature. Using the four-probe method, the electronic and magnetic transport properties have been investigated with and without magnetic field applied up to 4 T, The superconducting zero resistance temperature increases with the increase of the thickness of YBCO, ts, with ts>85 Å. The nature of resistance for LCMO is screened by YBCO with the thickness more than about 250 Å, but the magnetoresistance (MR) effect is observed in the bilayers. MR increases with the decrease of the thickness of YBCO. Structural characterizations of the bilayers show that there is interdiffusion appeared in the interface between LCMO and YBCO, and, LCMO and STO.
Physica C: Superconductivity.
-
[show abstract]
[hide abstract]
ABSTRACT: Filled skutterudite compounds La0.75Fe3CoSb12 with different porosities were synthesized using spark plasma sintering (SPS) and the Archimedes method was used to measure the porosities of the specimens. Phase constitutions and compositions of the compounds were examined by XRD and EPMA, and fracture surfaces of the compounds were observed by SEM. The effect of porosity on the thermoelectric properties was studied based on the changes in the electrical resistivity, Seebeck coefficient and thermal conductivity as a function of porosity. Our results show that the Seebeck coefficient is independent of porosity and the increase of electrical resistivity is consistent with the reduction of thermal conductivity due to scattering of carriers and phonons by pores. In addition, the thermoelectric figure of merit ZT (where T is temperature and Z is a function of the Seebeck coefficient, electrical resistivity, and thermal conductivity) of specimens with high porosity is comparable to that of specimens with low porosity. This suggests that the ZT value of La0.75Fe3CoSb12 compound does not depend significantly on the porosity.
Journal of Alloys and Compounds.
-
[show abstract]
[hide abstract]
ABSTRACT: K2Nb8O21 microwires with diameters of several hundred nanometers and lengths up to tens of microns were prepared by molten salt synthesis, and characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The as-synthesized microwires have semiconductor characteristics with band gap Eg of about 3.1 eV, consistent with electrical transport measurement of single microwire, which gives a resistivity of about 0.46 Ω m at room temperature. Microwave dielectric property measurement at 2–18 GHz shows that K2Nb8O21 microwires have a relative low complex permittivity. A weak dielectric relaxation occurs in the 12–16 GHz band due to the free charges polarization on the interfaces between K2Nb8O21 microwires and the PVB matrix.
Ceramics International. 35(8):3021-3025.
-
[show abstract]
[hide abstract]
ABSTRACT: Dynamic recrystallization and dynamic recovery in 7050 aluminum alloy during high temperature deformation have been investigated by tensile tests conducted at 460 °C and strain rates of 1.0 × 10− 2 and 0.1 s− 1. It is shown that continuous dynamic recrystallization and dynamic recovery are the softening mechanisms when strain rates are 1.0 × 10− 2 and 0.1 s− 1, respectively. The increase in the average misorientation angle is proportional to the increase in the true strain during continuous recrystallization and dynamic recovery. The grain size of the 7050 aluminum alloy increases with increasing true strain during continuous dynamic recrystallization and dynamic recovery, while the aspect ratio of grains remains unchanged after the continuous dynamic recrystallization; and it increases with the true strain during dynamic recovery. The continuous increase of the average misorientation angle during continuous dynamic recrystallization is attributed to the migration of subgrain boundaries and the absorption of dislocations into grain boundaries.
Materials Characterization. 59(9):1185-1189.
-
[show abstract]
[hide abstract]
ABSTRACT: Based on careful calibration in respect of 70 nm n-type strained Si channel Si/SiGe modulation doped FETs (MODFETs) fabricated by Daimler Chrysler, numerical simulations have been used to study the impact of the device geometry and various doping strategies on device performance and linearity. Both the lateral and vertical layer structures are crucial to achieve high RF performance or high linearity. The simulations suggest that gate length scaling helps to achieve higher RF performance, but degrades the linearity. Doped channel devices are found to be promising for high linearity applications. Trade-off design strategies are required for reconciling the demands of high device performance and high linearity simultaneously.
Microelectronics Reliability.
