80 research outputs found
Upregulated Expression of Cytotoxicity-Related Genes in IFN-γ Knockout Mice with Schistosoma japonicum Infection
It is well accepted that IFN-γ is important to the development of acquired resistance against murine schistosomiasis. However, the in vivo role of this immunoregulatory cytokine in helminth infection needs to be further investigated. In this study, parasite burden and host immune response were observed in IFN-γ knockout mice (IFNg KO) infected with Schistosoma japonicum for 6 weeks. The results suggested that deficiency in IFN-γ led to decreased egg burden in mice, with low schistosome-specific IgG antibody response and enhanced activation of T cells during acute infection. Microarray and qRT-PCR data analyses showed significant upregulation of some cytotoxicity-related genes, including those from the granzyme family, tumor necrosis factor, Fas Ligand, and chemokines, in the spleen cells of IFNg KO mice. Furthermore, CD8+ cells instead of NK cells of IFNg KO mice exhibited increased transcription of cytotoxic genes compared with WT mice. Additionally, Schistosoma japonicum-specific egg antigen immunization also could activate CD8+ T cells to upregulate the expression of cytotoxic genes in IFNg KO mice. Our data suggest that IFN-γ is not always a positive regulator of immune responses. In certain situations, the disruption of IFN-γ signaling may up-regulate the cytotoxic T-cell-mediated immune responses to the parasite
Photochemical origin of SiC in the circumstellar envelope of carbon-rich AGB stars revealed by ALMA
Whether SiC is a parent species, that is formed in the photosphere or as
a by-product of high-temperature dust formation, or a daughter species, formed
in a chemistry driven by the photodestruction of parent species in the outer
envelope, has been debated for a long time. Here, we analyze the ALMA
observations of four SiC transitions in the CSEs of three C-rich AGB stars
(AI Vol, II Lup, and RAFGL 4211), and found that SiC exhibits an annular,
shell-like distribution in these targets, suggesting that SiC can be a
daughter species in the CSEs of carbon-rich AGB stars. The results can provide
important references for future chemical models.Comment: Accepted in Frontiers in Astronomy and Space Science
The Lunar Lander Neutron and Dosimetry (LND) Experiment on Chang'E 4
Chang'E 4 is the first mission to the far side of the Moon and consists of a
lander, a rover, and a relay spacecraft. Lander and rover were launched at
18:23 UTC on December 7, 2018 and landed in the von K\'arm\'an crater at 02:26
UTC on January 3, 2019. Here we describe the Lunar Lander Neutron \& Dosimetry
experiment (LND) which is part of the Chang'E 4 Lander scientific payload. Its
chief scientific goal is to obtain first active dosimetric measurements on the
surface of the Moon. LND also provides observations of fast neutrons which are
a result of the interaction of high-energy particle radiation with the lunar
regolith and of their thermalized counterpart, thermal neutrons, which are a
sensitive indicator of subsurface water content.Comment: 38 pages, submitted to Space Science Review
Spatial Organization and Molecular Correlation of Tumor-Infiltrating Lymphocytes Using Deep Learning on Pathology Images
Beyond sample curation and basic pathologic characterization, the digitized H&E-stained images
of TCGA samples remain underutilized. To highlight this resource, we present mappings of tumorinfiltrating lymphocytes (TILs) based on H&E images from 13 TCGA tumor types. These TIL
maps are derived through computational staining using a convolutional neural network trained to
classify patches of images. Affinity propagation revealed local spatial structure in TIL patterns and
correlation with overall survival. TIL map structural patterns were grouped using standard
histopathological parameters. These patterns are enriched in particular T cell subpopulations
derived from molecular measures. TIL densities and spatial structure were differentially enriched
among tumor types, immune subtypes, and tumor molecular subtypes, implying that spatial
infiltrate state could reflect particular tumor cell aberration states. Obtaining spatial lymphocytic
patterns linked to the rich genomic characterization of TCGA samples demonstrates one use for
the TCGA image archives with insights into the tumor-immune microenvironment
Individualism and stock price crash risk
Employing a sample of 26,473 firms across 42 countries from 1990 to 2013, we find that firms located in countries with higher individualism have higher stock price crash risk. Furthermore, individualism can be transmitted by foreign investors from overseas markets to influence local firms’ crash risk, and can exacerbate the impact of firm risk taking and earnings management on crash risk. Moreover, the positive relation between individualism and crash risk is amplified during the global financial crisis and attenuated by enhanced country-level financial information transparency and the adoption of International Financial Reporting Standards
Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples
Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts
Seismic Resilience Enhancement of Urban Water Distribution System Using Restoration Priority of Pipeline Damages
The malfunction of the water distribution system (WDS) following severe earthquakes have significant impacts on the post-earthquake rescue. Moreover, the restoration priority of earthquake-induced pipeline damages plays an important role in improving the post-earthquake serviceability of WDS and the “seismic resilience”. Thus, to enhance the seismic resilience of WDS, this study develops a dynamic cost-benefit method and introduces three existing methods to determine the restoration priority of pipeline damages based on a quantitative resilience evaluation framework. In this resilience evaluation framework, the restoration priority is firstly determined. Then the time-varying performance of post-earthquake WDS is modeled as a discrete event dynamic system. In this model, the system state changes after the reparation of pipeline damage, and the system performance is simulated by a hydraulic model to be consistent with the system state. In this study, this method is also tested and compared with other existing methods, and the results show that the system resilience corresponding to the restoration priority obtained by this method is close to that obtained by the global optimization method with a relative difference of less than 3%, whereas the calculation complexity is about 0.4% of the optimization model. It is concluded that this proposed method is valid
Landmark-Based Inertial Navigation System for Autonomous Navigation of Missile Platform
As a new information provider of autonomous navigation, the on-orbit landmark observation offers a new means to improve the accuracy of autonomous positioning and attitude determination. A novel autonomous navigation method based on the landmark observation and the inertial system is designed to achieve the high-accuracy estimation of the missile platform state. In the proposed method, the navigation scheme is constructed first. The implicit observation equation about the deviation of the inertial system output is derived and the Kalman filter is applied to estimate the missile platform state. Moreover, the physical observability of the landmark and the mathematical observability of the navigation system are analyzed. Finally, advantages of the proposed autonomous navigation method are demonstrated through simulations compared with the traditional celestial-inertial navigation system and the deeply integrated celestial-inertial navigation system
Design and Test of a Straw-Clearing-Depth Self-Adaptive Control System of a Front-Mounted Seedbed-Preparation Device
In northeast China, most seedbed-preparation devices use the ground-wheel profiling method to ensure their operational stability. However, during the wide-width operation of the front-mounted seedbed-preparation device, the poor trafficability characteristics and the low profiling accuracy of the ground-wheel profiling mechanism result in unstable straw clearing depth, poor straw clearing quality, and the low operational efficiency of the seedbed-preparation device. In order to solve the above problems, a straw-clearing-depth self-adaptive control system of a front-mounted seedbed-preparation device was designed. The key structural design of the self-adaptive control system was completed through theoretical analysis. The performance test results of the self-adaptive control system showed that the lifting speed of the front-suspension mechanism was greater than 0.2 m/s in the manual button control mode, and the relative error between the target value and the actual value of the straw clearing depth was 10.8% under the self-adaptive profiling control mode. The three-factor and five-level quadratic regression orthogonal rotation center combination test method was adopted to conduct a parameter combination optimization test, with the machine operation speed, the operation depth of the straw clearing knife, and the straw covering amount as test factors, and the straw clearing rate, the qualified rate of operation depth, and the consistency of straw clearing between rows as evaluation indices. The results indicated that when the machine operation speed was 5~8.8 km/h, the operation depth of the straw clearing knife was 50 mm, the straw covering amount was 0.9~1.44 kg/m2, the straw clearing rate was ≥86%, the qualified rate of operation depth was ≥86%, and the consistency of straw clearing between rows was ≥83%. Field tests were carried out on the machine using operation speeds of 5 km/h, 6 km/h, 7 km/h, and 8 km/h under the conditions of an operation depth of the straw clearing knife of 50 mm and a straw covering amount of 1.2 kg/m2. The results showed that the straw clearing rate, the qualified rate of operation depth, and the consistency of straw clearing between rows were all within the optimized range under different machine operation speeds, which was basically consistent with the optimized results
Parameter Combination Optimization of the Lateral Straw Clearing and Throwing Knife Based on Discrete Element Simulation
In order to explore the laws of corn straw lateral moving and throwing, it is necessary to identify the main factors that restrict improvements in the quality of straw clearing and reductions in power consumption and then optimize the knife parameter combinations; in this paper, the kinematic analysis of single-stage lateral moving and throwing of corn straw was carried out, and the mathematical model for the collision process between the knife and straw is established. Key factors affecting the lateral moving and throwing efficiency of straw were determined according to the model analysis. A parameter combination optimization test was conducted with three-factor and five-level quadratic regression orthogonal rotation center combination test methods and discrete element virtual simulation, taking into account the edge angle of cutting, the rotation radius of the knife, and the rotation speed of the knife roller as test factors and the straw clearing rate and power consumption as performance evaluation indexes. The test results showed that at a travel speed of 7.2 km/h when the edge angle of cutting was 65°, the rotation radius of the knife was 420 mm, and the rotation speed of the knife roller was 538~600 rpm, the straw clearing rate was ≥85%, and power consumption was ≤1.5 kW. The field test was carried out to verify the optimized results, and the test results showed that the test values of the performance evaluation indexes were all in the ranges of the optimized interval. These research results lay down the foundation for the design of lateral straw clearing and throwing knives
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