Monte Carlo Simulation for Polychromatic X-ray Fluorescence Computed Tomography with Sheet-Beam Geometry

X-ray fluorescence computed tomography based on sheet-beam can save a huge amount of time to obtain a whole set of projections using synchrotron. However, it is clearly unpractical for most biomedical research laboratories. In this paper, polychromatic X-ray fluorescence computed tomography with sheet-beam geometry is tested by Monte Carlo simulation. First, two phantoms (A and B) filled with PMMA are used to simulate imaging process through GEANT 4. Phantom A contains several GNP-loaded regions with the same size (10 mm) in height and diameter but different Au weight concentration ranging from 0.3% to 1.8%. Phantom B contains twelve GNP-loaded regions with the same Au weight concentration (1.6%) but different diameter ranging from 1mm to 9mm. Second, discretized presentation of imaging model is established to reconstruct more accurate XFCT images. Third, XFCT images of phantom A and B are reconstructed by fliter backprojection (FBP) and maximum likelihood expectation maximization (MLEM) with and without correction, respectively. Contrast to noise ratio (CNR) is calculated to evaluate all the reconstructed images. Our results show that it is feasible for sheet-beam XFCT system based on polychromatic X-ray source and the discretized imaging model can be used to reconstruct more accurate images

The uterine expression of SEC63 gene is up-regulated at implantation sites in association with the decidualization during the early pregnancy in mice

<p>Abstract</p> <p>Background</p> <p>Sec63 is a key component of the protein translocation machinery in the mammalian endoplasmic reticulum (ER), and involved in the post-translation processing of secretory proteins. The aim of this study was to determine the expression pattern of SEC63 gene in mouse uterus during the early pregnancy.</p> <p>Methods</p> <p>Real-time quantitative PCR and Western blot analyses were used to evaluate the alteration in levels of uterine <it>SEC63 </it>gene expression during the peri-implantation period in mice. Further, both in situ hybridization and immunohistochemical analyses were performed to examine the spatial localization of SEC63 gene expression in mouse uterine tissues. The presence of Sec63 protein in human uterine tissue was also detected by immunohistochemical analysis. Statistical analysis was carried out using Tukey test.</p> <p>Results</p> <p>Uterine SEC63 gene expression was up-regulated and predominantly localized in mouse decidual cells during days 5–8 of pregnancy. More interestingly, Sec63 protein was also detected in human decidua of 10-week pregnancy, whereas was not observed in human endometrial tissues both at proliferative and secretory phases of menstrual cycle.</p> <p>Conclusion</p> <p>The pattern of SEC63 gene expression is consistent with a possible role for SEC63 in decidualization.</p

Thermomechanical processing of cost-affordable powder metallurgy Ti-5Fe alloys from the blended elemental approach: Microstructure, tensile deformation behavior, and failure

The development of cost-affordable Ti alloys is key for the application of Ti in other industries like the automobile sector. Therefore, a combination of powder metallurgy (PM) and low-cost compositions is an interesting approach. In this article, a cost-affordable PM Ti-5Fe alloy is processed following the blended elemental route and extruded at high temperature to remove porosity. Different extrusion temperatures and heat treatments (i.e., solution treatment and aging, STA) are performed to obtain ultrafine microstructures, and their effect on the mechanical behavior is studied. For extrusions in the β phase, microstructures consist of coarse lamellar colonies, resulting in alloys with improved properties compared to the as-sintered alloy but still lacking toughness due to the failure happening just after necking onset. Extruding in the α + β phase results in a bimodal microstructure of fine elongated primary α and coarse lamellar colonies, and the alloy becomes tougher. STA with aging below the eutectoid temperature of 590 °C leads to a hard but brittle alloy, whereas STA with aging above it results in alloys with strength comparable to the as-extruded conditions and enhanced ductility

JSSDR: Joint-Sparse Sensory Data Recovery in Wireless Sensor Networks

Abstract-Data loss is ubiquitous in wireless sensor networks (WSNs) mainly due to the unreliable wireless transmission, which results in incomplete sensory data sets. However, the completeness of a data set directly determines its availability and usefulness. Thus, sensory data recovery is an indispensable operation against the data loss problem. However, existing solutions cannot achieve satisfactory accuracy due to special loss patterns and high loss rates in WSNs. In this work, we propose a novel sensory data recovery algorithm which exploits the spatial and temporal jointsparse feature. Firstly, by mining two real datasets, namely the Intel Indoor project and the GreenOrbs project, we find that: (1) for one attribute, sensory readings at nearby nodes exhibit inter-node correlation; (2) for two attributes, sensory readings at the same node exhibit inter-attribute correlation; (3) these inter-node and inter-attribute correlations can be modeled as the spatial and temporal joint-sparse features, respectively. Secondly, motivated by these observations, we propose two JointSparse Sensory Data Recovery (JSSDR) algorithms to promote the recovery accuracy. Finally, real data-based simulations show that JSSDR outperforms existing solutions. Typically, when the loss rate is less than 65%, JSSDR can estimate missing values with less than 10% error. And when the loss rate reaches as high as 80%, the missing values can be estimated by JSSDR with less than 20% error

Photoelectrochemical study on the complex of PASP and tungstate as inhibitors of cupronickel B10's corrosion

Photoelectrochemical and AC impedance measurements were conducted to study the effects of environment-friendly inhibitors poly-aspartate(PASP), Na2WO4 and their complex on the corrosion of cupronickel B10 in a borax-buffer solution. The photoelectrochemical measurement results indicated that PASP or Na2WO4 increased the p-type photocurrent which came from the Cu2O layer on the B10 surface. It showed that the inhibitors increased the thickness of the Cu2O layer and decreased the corrosion speed. The optimal concentrations of PASP and Na2WO4 was 3 and 5 mg.L-1, respectively. Na2WO4 increased photocurrent more than mono PASP did. Combined use of PASP and Na2WO4 in a total concentration of 5 mg.L-1, when the mass ratio(PASP: Na2WO4) was 1:1 or 1:3, increased the photocurrent more than their individual use did. The bigger the photocurrent was, the better the inhibition efficiency was. When the mass ratio (PASP: Na2WO4) was 3:1, the combined use increased photocurrent less than their individual use did, the inhibition effect decreased. AC impedance measurement results were well agreed to the photoelectrochemical results

Inhibition action of the self-assembled monolayers of 3-amino-1,2,4-triazole on brass

The anticorrosion and inhibiting mechanism for the self-assembled monolayers (SAMs) of 3-amino-1,2,4-triazole (ATA) on the surface of brass had been investigated by electrochemical method, as well as its adsorption behavior. The results indicated that ATA was liable to interact with brass forming SAMs on the surface of brass. The SAMs changed the structure of the electric-double layer. The SAMs restrained the process of anodic oxidation and had well anticorrosion effect. It was in good agreement with the results by EIS and polarization curve methods. The results from electrochemical measurements indicated that the corrosion resistance for brass electrode was improved by the ATA SAMs. Adsorption of the ATA SAMs was found to follow the Langmuir's adsorption isotherm, and the adsorption mechanism was typical chemisorption