765 research outputs found
Theory of magnetoelectric photocurrent generated by direct interband transitions in semiconductor quantum well
A linearly polarized light normally incident on a semiconductor quantum well
with spin-orbit coupling may generate pure spin current via direct interband
optical transition. An electric photocurrent can be extracted from the pure
spin current when an in-plane magnetic field is applied, which has been
recently observed in the InGaAs/InAlAs quantum well [Dai et al., Phys. Rev.
Lett. 104, 246601 (2010)]. Here we present a theoretical study of this
magnetoelectric photocurrent effect associated with the interband transition.
By employing the density matrix formalism, we show that the photoexcited
carrier density has an anisotropic distribution in k space, strongly dependent
on the orientation of the electron wavevector and the polarization of the
light. This anisotropy provides an intuitive picture of the observed dependence
of the photocurrent on the magnetic field and the polarization of the light. We
also show that the ratio of the pure spin photocurrent to the magnetoelectric
photocurrent is approximately equal to the ratio of the kinetic energy to the
Zeeman energy, which enables us to estimate the magnitude of the pure spin
photocurrent. The photocurrent density calculated with the help of an
anisotropic Rashba model and the Kohn-Luttinger model can produce all three
terms in the fitting formula for measured current, with comparable order of
magnitude, but discrepancies are still present and further investigation is
needed.Comment: 13 pages, 9 figures, 2 table
UV R-CNN: Stable and Efficient Dense Human Pose Estimation
Dense pose estimation is a dense 3D prediction task for instance-level human
analysis, aiming to map human pixels from an RGB image to a 3D surface of the
human body. Due to a large amount of surface point regression, the training
process appears to be easy to collapse compared to other region-based human
instance analyzing tasks. By analyzing the loss formulation of the existing
dense pose estimation model, we introduce a novel point regression loss
function, named Dense Points} loss to stable the training progress, and a new
balanced loss weighting strategy to handle the multi-task losses. With the
above novelties, we propose a brand new architecture, named UV R-CNN. Without
auxiliary supervision and external knowledge from other tasks, UV R-CNN can
handle many complicated issues in dense pose model training progress, achieving
65.0% and 66.1% on the DensePose-COCO validation subset
with ResNet-50-FPN feature extractor, competitive among the state-of-the-art
dense human pose estimation methods.Comment: 9pages, 4 figure
Sulfadiazine Sodium Ameliorates the Metabolomic Perturbation in Mice Infected with Toxoplasma gondii
In this study, we analyzed the global metabolomic changes associated with Toxoplasma gondii infection in mice in the presence or absence of sulfadiazine sodium (SDZ) treatment. BALB/c mice were infected with T. gondii GT1 strain and treated orally with SDZ (250 g/ml in water) for 12 consecutive days. Mice showed typical manifestations of illness at 20 days postinfection (dpi); by 30 dpi, 20% had survived and developed latent infection. We used ultraperformance liquid chromatography-mass spectrometry to profile the serum metabolomes in control (untreated and uninfected) mice, acutely infected mice, and SDZ-treated and infected mice. Infection induced significant perturbations in the metabolism of-linolenic acid, purine, pyrimidine, arginine, tryptophan, valine, glycerophospholipids, and fatty acyls. However, treatment with SDZ seemed to alleviate the serum metabolic alterations caused by infection. The restoration of the serum metabolite levels in the treated mice was associated with better clinical outcomes. These data indicate that untargeted metabolomics can reveal biochemical pathways associated with restoration of the metabolic status of T. gondii-infected mice following SDZ treatment and could be used to monitor responses to SDZ treatment. This study provides a new systems approach to elucidate the metabolic and therapeutic effects of SDZ in the context of murine toxoplasmosis. K E Y W O R D S Toxoplasma gondii, biomarkers, metabolomics, mice, serum metabolites, sulfadiazine sodium Toxoplasma gondii, an obligate intracellular protozoan parasite, is highly prevalent in warm-blooded animals and humans (1). T. gondii comprises three clonal lineages (type I, type II, and type III) (2). Despite 98% genetic similarity, dramatic differences in virulence exist among strains belonging to these T. gondii genotypes (3). Humans acquire infection mainly by ingesting undercooked meat containing tissue cysts or oocysts from contaminated water (4). Acute infection with this parasite is mediated by the aggressive, fast-replicating, tachyzoite stage, which can cause encephalitis or retinochoroiditis. In addition, reactivation of the latent form (i.e., bradyzoites-containing cysts) of T. gondii can cause life-threatening conditions and even death in immuno-compromised individuals (5)
A convenient tandem one-pot synthesis of donor-acceptor-type triphenylene 2,3-dicarboxylic esters from diarylacetylene
A tandem one-pot method for the direct synthesis of polysubstituted triphenylene 2,3-dicarboxylic esters with different substitution patterns was developed by enyne metathesis of diarylacetylene, followed by Diels–Alder, aromatization and a cyclization cascade
A dinuclear copper complex: bis(μ-4-aminobenzoato)bis[aqua(1,10-phenanthroline)copper(II)] dichloride bis(4-aminobenzoic acid) dihydrate
The title complex, [Cu2(C7H6NO2)2(C12H8N2)2(H2O)2]·2C7H7NO2·2H2O, consists of a dinuclear [Cu2(C7H6NO2)2(C12H8N2)2(H2O)2]2+ cation, two Cl− anions, two 4-aminobenzoic acid molecules and two disordered water molecules (site occupancy factors 0.5). The Cu(II) ion adopts a distorted square-pyramidal geometry formed by two N atoms from the 1,10-phenanthroline ligand and two O atoms of the two 4-aminobenzoic acid ligands and one water O atom. The Cu⋯Cu separation is 3.109 (2) Å. A twofold axis passes through the mid-point of the Cu⋯Cu vector
Serum metabolic profiling of oocyst-induced Toxoplasma gondii acute and chronic infections in mice using mass-spectrometry
Toxoplasma gondii is an obligate intracellular parasite causing severe diseases in immunocompromised individuals and congenitally infected neonates, such as toxoplasmosis encephalitis and toxoplasmic chorioretinitis. This study aimed to determine whether serum metabolic profiling can (i) identify metabolites associated with oocyst-induced T. gondii infection and (ii) detect systemic metabolic differences between T. gondii -infected mice patients and controls. We performed the first global metabolomics analysis of mice serum challenged with 100 sporulated T. gondii Pru oocysts (Genotype II). Sera from acutely infected mice (11 days post-infection, dpi), chronically infected mice (33 dpi) and control mice were collected and analysed using LC-MS/MS platform. Following False Discovery Rate filtering, we identified 3871 and 2825 ions in ESI + or ESI − mode, respectively. Principal Component Analysis (PCA) and Partial Least Squares Discriminant Analysis (PLS -DA) identified metabolomics profiles that clearly differentiated T. gondii -infected and -uninfected serum samples. Acute infection significantly influenced the serum metabolonme. Our results identified common and uniquely perturbed metabolites and pathways. Acutely infected mice showed perturbations in metabolites associated with glycerophospholipid metabolism, biosynthesis of amino acid, and tyrosine metabolism. These findings demonstrated that acute T. gondii oocyst induces a global perturbation of mice serum metabolonme, providing new insights into the mechanisms underlying systemic metabolic changes during early stage of T. gondii oocyst infection
Elevated circulating level of P2X7 receptor is related to severity of coronary artery stenosis and prognosis of acute myocardial infarction
Background: Acute myocardial infarction (AMI) is a severely life-threatening cardiovascular disease. Previous research has identified an association between the P2X7 receptor (P2X7R) and the development of atherosclerosis. However, the correlation of its expression with the clinical prognosis of patients with AMI remains unclear. The present study aimed to investigate the potential role of P2X7R in Chinese patients with AMI.
Methods: Seventy-nine patients with AMI and 48 controls were consecutively enrolled in this prospective observational study. Circulating P2X7R mRNA expression levels and other clinical variables were determined upon admission to the hospital. Patients were followed up for 360 days, and the end-point was considered as the occurrence of major adverse cardiovascular events (MACE).
Results: Circulating P2X7R mRNA expression level in peripheral blood mononuclear cells of patients with AMI were significantly higher than those in controls and had promising diagnostic ability of AMI with an area under the curve of 0.928. Furthermore, P2X7R was demonstrated to be correlated positively with the severity of coronary artery stenosis. Additionally, this is the first study to indicate that higher P2X7R mRNA expression is associated with a higher rate of MACE within 360 days after AMI.
Conclusions: The present study showed that the circulating level of P2X7R was elevated in AMI patients and was closely associated with the severity of coronary artery stenosis and prognosis of AMI
A new polymorph of 5,5′-(ethane-1,2-diyl)bis(1H-tetrazole)
The asymmetric unit of the title compound, C4H6N8, contains a quarter of the molecule, which possesses a crystallographically imposed centre of symmetry with all non-H atoms situated on a mirror plane. The crystal packing exhibits intermolecular N—H⋯N hydrogen bonds and π–π stacking interactions between the tetrazole rings of adjacent molecules [centroid–centroid distance = 3.4402 (10) Å]
Isospin dependence of projectile-like fragment production at intermediate energies
The cross sections of fragments produced in 140 MeV Ca + Be
and Ni + Be reactions are calculated by the statistical
abration-ablation(SAA) model and compared to the experimental results measured
at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State
University. The fragment isotopic and isotonic cross section distributions of
Ca and Ca, Ni and Ni, Ca and Ni, and
Ca and Ni are compared and the isospin dependence of the
projectile fragmentation is studied. It is found that the isospin dependence
decreases and disappears in the central collisions. The shapes of the fragment
isotopic and isotonic cross section distributions are found to be very similar
for symmetric projectile nuclei. The shapes of the fragment isotopic and
isotonic distributions of different asymmetric projectiles produced in
peripheral reactions are found very similar. The similarity of the
distributions are related to the similar proton and neutron density
distributions inside the nucleus in framework of the SAA model.Comment: 7 pages, 4 figures; to be published in Phys Rev
Detection of micrometastases in peripheral blood of non-small cell lung cancer with a refined immunomagnetic nanoparticle enrichment assay
Fe3O4 particles are currently used as the core of immunomagnetic microspheres in the immunomagnetic enrichment assay of circulating tumor cells (CTCs). It is difficult to further improve the sensitivity of CTC detection or to improve tumor cell-type identification and characterization. In the present study, we prepared immunomagnetic nanoparticles with nanopure iron as the core, coated with anti-cytokeratin 7/8 (CK7/8) monoclonal antibody. These immunomagnetic nanoparticles (IMPs) were used in conjunction with immunocytochemistry (ICC) to establish a refined immunomagnetic nanoparticle enrichment assay for CTC detection in non-small cell lung cancer (NSCLC). The assay was compared with nested reverse transcription polymerase chain reaction (RT-PCR) to detect CK19 mRNA and lung specific X protein (LUNX) mRNA. Human lung adenocarcinoma cell line A549 was used for sensitivity and specificity evaluation. Peripheral blood samples were collected from each group for CTC detection. The average diameter of the immunomagnetic nanoparticles was 51 nm, and the amount of adsorbed antibodies was 111.2 μg/mg. We could detect down to one tumor cell in 5 × 107 peripheral blood mononuclear cells. The sensitivity was consistent with that of nested RT-PCR; however, the false positive rate was significantly reduced. The modified assay combined with ICC did not differ from nested RT-PCR in sensitivity, but it had significantly increased specificity. This approach could, therefore, contribute to identification of micrometastases, re-defining clinical staging, and guiding individual postoperative treatments. The technique shows considerable potential clinical value and further clinical trials are warranted
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