346 research outputs found
Single crystalline Co3O4 nanocrystals exposed with different crystal planes for Li-o2 batteries
Single crystalline Co3O4 nanocrystals exposed with different crystal planes were synthesised, including cubic Co3O4 nanocrystals enclosed by {100} crystal planes, pseudo octahedral Co3O4 enclosed by {100} and {110} crystal planes, Co3O4 nanosheets exposed by {110} crystal planes, hexagonal Co3O4 nanoplatelets exposed with {111} crystal planes, and Co3O4 nanolaminar exposed with {112} crystal planes. Well single crystalline features of these Co3O4 nanocrystals were confirmed by FESEM and HRTEM analyses. The electrochemical performance for Li-O2 batteries shows that Co3O4 nanocrystals can significantly reduce the discharge-charge over-potential via the effect on the oxygen evolution reaction (OER). From the comparison on their catalytic performances, we found that the essential factor to promote the oxygen evolution reactions is the surface crystal planes of Co3O4 nanocrystals, namely, crystal planes-dependent process. The correlation between different Co3O4 crystal planes and their effect on reducing charge-discharge over-potential was established: {100} \u3c {110} \u3c {112} \u3c {111}
Role of hypoxia-inducible factor in diabetic myocardial hypertrophy
Purpose: This study was carried out to investigate the role of hypoxia-inducible factor (HIF) in diabetic cardiomyopathy in vitro.Methods: Hypoxia was induced chemically in H9C2 cells (cardiac hypertrophy model), and the cells were treated with phenylephrine (PE), deferoxamine (DFO), PE + DFO, and HIF-1α siRNA under conditions of high and normal glucose. Western blot was used to analyze the expression of some glycolytic proteins, including Glut-1, hexokinase (HXK-2), and enolase, while apoptosis of H9C2 was determined by flow cytometry.Results: PE caused hypertrophy in H9C2, which was ameliorated by HIF-1α. Compared to normal, under prolonged high glucose, the low expression of HIF-1α led to low expressions of Glut-1, HXK-2 and enolase. However, expression of HIF-1α decreased, while those of Bax and Caspase 3 increased, and Bcl-2 expression decreased. Furthermore, under short time high glucose, HIF-1α caused apoptosis of hypertrophic cardiomyocytes.Conclusion: HIF-1 mediates diabetic myocardial hypertrophy, probably as a function of the degree of high glucose exposure and hypoxia.Keywords: H9C2 cardiomyocyte, Hypoxia-inducible factor, Myocardial hypertrophy, Diabetic cardiomyopath
Neural Filters for Jet Analysis
We study the efficiency of a neural-net filter and deconvolution method for
estimating jet energies and spectra in high-background reactions such as
nuclear collisions at the relativistic heavy-ion collider and the large hadron
collider. The optimal network is shown to be surprisingly close but not
identical to a linear high-pass filter. A suitably constrained deconvolution
method is shown to uncover accurately the underlying jet distribution in spite
of the broad network response. Finally, we show that possible changes of the
jet spectrum in nuclear collisions can be analyzed quantitatively, in terms of
an effective energy loss with the proposed method. {} {Dong D W and Gyulassy M
1993}{Neural filters for jet analysis}
{(LBL-31560) Physical Review E Vol~47(4) pp~2913-2922}Comment: 21 pages of Postscript, (LBL-31560
Analytical Model for Concrete Jacketed RC Columns with Precorrosion and Postcorrosion Damages Under Uniaxial Loading
The main objective of this study is to investigate the effect of precorrosion and postcorrosion damage on concrete jacketed RC columns under uniaxial loading and to develop a rational methodology for predicting the corresponding compressive strength. The predamage and postdamage involved an electrochemical process to accelerate the migration of chlorides from an external electrolyte into the tested columns and a wettingâdrying cycle process with a controlled current to speed up the corrosion of the reinforcing steel bars in the tested columns. An uniaxial loading test was to determine the structural performance of the concrete jacketed columns with or without corrosion damage. The failure mode, loadâdisplacement, and loadâstrain responses of test columns were recorded, and the related mechanisms were discussed. Then a model that is capable of evaluating peak load of unjacketed or jacketed RC columns with or without corrosion damage was developed. The analytical approach considered the effect of reinforcement corrosion on the effective load-bearing area of concrete and the confinement effect from the web reinforcement. The analytical results agreed well with the experimental results, indicating the reliability and effectiveness of developed models
Autologistic network model on binary data for disease progression study
This paper focuses on analysis of spatiotemporal binary data with absorbing states. The research was motivated by a clinical study on amyotrophic lateral sclerosis (ALS), a neurological disease marked by gradual loss of muscle strength over time in multiple body regions. We propose an autologistic regression model to capture complex spatial and temporal dependencies in muscle strength among different muscles. As it is not clear how the disease spreads from one muscle to another, it may not be reasonable to define a neighborhood structure based on spatial proximity. Relaxing the requirement for prespecification of spatial neighborhoods as in existing models, our method identifies an underlying network structure empirically to describe the pattern of spreading disease. The model also allows the network autoregressive effects to vary depending on the musclesâ previous status. Based on the joint distribution derived from this autologistic model, the joint transition probabilities of responses among locations can be estimated and the disease status can be predicted in the next time interval. Model parameters are estimated through maximization of penalized pseudoâlikelihood. Postmodel selection inference was conducted via a biasâcorrection method, for which the asymptotic distributions were derived. Simulation studies were conducted to evaluate the performance of the proposed method. The method was applied to the analysis of muscle strength loss from the ALS clinical study.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152664/1/biom13111.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152664/2/biom13111-sup-0001-autolog_supp-biom.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152664/3/biom13111-sup-0003-supmat.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152664/4/biom13111_am.pd
Ruthenium nanocrystal decorated vertical graphene nanosheets@Ni foam as highly efficient cathode catalysts for lithium-oxygen batteries
The electrochemical performance of lithium-oxygen (Li-O2) batteries can be markedly improved through designing the architecture of cathode electrodes with sufficient spaces to facilitate the diffusion of oxygen and accommodate the discharge products, and optimizing the cathode catalyst to promote the oxygen reduction reaction and oxygen evolution reaction (OER). Herein, we report the synthesis of ruthenium (Ru) nanocrystal-decorated vertically aligned graphene nanosheets (VGNS) grown on nickel (Ni) foam. As an effective binder-free cathode catalyst for Li-O2 batteries, the Ru-decorated VGNS@Ni foam can significantly reduce the charge overpotential via the effects on the OER and achieve high specific capacity, leading to an enhanced electrochemical performance. The Ru-decorated VGNS@Ni foam electrode has demonstrated low charge overpotential of ~0.45âV and high reversible capacity of 23â864âmAhâgâ1 at the current density of 200âmAâgâ1, which can be maintained for 50 cycles under full charge and discharge testing condition in the voltage range of 2.0-4.2âV. Furthermore, Ru nanocrystal decorated VGNS@Ni foam can be cycled for more than 200 cycles with a low overpotential of 0.23âV under the capacity curtained to be 1000âmAhâgâ1 at a current density of 200âmAâgâ1. Ru-decorated VGNS@Ni foam electrodes have also achieved excellent high rate and long cyclability performance. This superior electrochemical performance should be ascribed to the unique three-dimensional porous nanoarchitecture of the VGNS@Ni foam electrodes, which provide sufficient pores for the diffusion of oxygen and storage of the discharge product (Li2O2), and the effective catalytic effect of Ru nanocrystals on the OER, respectively. Ex situ field emission scanning electron microscopy, X-ray diffraction, Raman and Fourier transform infrared measurements revealed that Ru-decorated VGNS@Ni foam can effectively decompose the discharge product Li2O2, facilitate the OER and lead to a high round-trip efficiency. Therefore, Ru-decorated VGNS@Ni foam is a promising cathode catalyst for rechargeable Li-O2 batteries with low charge overpotential, long cycle life and high specific capacity
The Arabidopsis SAL1-PAP Pathway: A Case Study for Integrating Chloroplast Retrograde, Light and Hormonal Signaling in Modulating Plant Growth and Development?
Plant growth and development are dependent on chloroplast development and function. Constitutive high level accumulation of a chloroplast stress signal, 3âČ-phosphoadenosine-5âČ-phosphate (PAP), confers drought tolerance to plants, but slow downs and alters plant growth and development. PAP, a by-product of sulfur metabolism, is maintained at very low levels by the SAL1 phosphatase during vegetative growth of Arabidopsis and accumulates in rosettes during drought and excess light. Eight independent forward genetic screens in Arabidopsis identified SAL1 as the regulator of multiple phenotypes related to stress responses, hormonal signaling and/or perception. In this perspective article, we collate all the sal1 phenotypes published in the past two decades, and distill the different pathways affected. Our meta-analysis of publicly available sal1 microarray data coupled to preliminary hormonal treatment and profiling results on sal1 indicate that homeostasis and responses to multiple hormones in sal1 are altered during rosette growth, suggesting a potential connection between SAL1-PAP stress retrograde pathway and hormonal signaling. We propose the SAL1-PAP pathway as a case study for integrating chloroplast retrograde signaling, light signaling and hormonal signaling in plant growth and morphogenesis
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