3,862 research outputs found
Role of CD28/B7 costimulation and IL-12/IL-10 interaction in the radiation-induced immune changes
BACKGROUND: The present paper aims at studying the role of B7/CD28 interaction and related cytokine production in the immunological changes after exposure to different doses of ionizing radiation. RESULTS: The stimulatory effect of low dose radiation (LDR) on the proliferative response of lymphocytes to Con A was found to require the presence of APCs. The addition of APCs obtained from both low- and high-dose-irradiated mice to splenic lymphocytes separated from low-dose-irradiated mice caused stimulation of lymphocyte proliferation. B7-1/2 expression on APCs was up-regulated after both low and high doses of radiation. There was up-regulation of CD28 expression on splenic and thymic lymphocytes after LDR and its suppression after high dose radiation (HDR), and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) expression showed changes in the opposite direction. IL-12 secretion by macrophages was stimulated after both low and high doses of radiation, but IL-10 synthesis by splenocytes was suppressed by low dose radiation and up-regulated by high dose radiation. CONCLUSION: The status of CD28/CTLA-4 expression on T lymphocytes in the presence of up-regulated B7 expression on APCs determined the outcome of the immune changes in response to radiation, i.e., up-regulation of CD28 after LDR resulted in immunoenhancement, and up-regulation of CTLA-4 associated with down-regulation of CD28 after HDR led to immunosuppression. Both low and high doses of radiation up-regulated B7-1/2 expression on APCs. After LDR, the stimulated proliferative effect of increased IL-12 secretion by APCs, reinforced by the suppressed secretion of IL-10, further strengthened the intracellular signaling induced by B7-CD28 interaction
EXPERIMENTAL STUDY OF TWO LARGE-SCALE MODELS’ SEAKEEPING PERFORMANCE IN COASTAL WAVES
Actual sea waves and vessel motion are an unsteady nonlinear random process. The currently adopted test to simulate wave impact of vessel models in tank can\u27t fully reveal the impact of real sea waves on vessel swing motion. In this paper the buoy wave height meter is adopted to carry out measurements and analyses of the coastal wave environment. The correlation between the coastal wave spectra and the ocean wave spectra is analyzed. The test system is established for remote control and telemetry self-propelled vessel models suitable for the experiment conducted in the coastal areas. The seakeeping performance test is conducted for the same tonnage of round bilge vessel model and the deep-V hybrid monohull of large-scale vessel model under the coastal wave conditions. The experimental results are compared with the test results of small-scale vessel model in the towing tank. The experimental results show that the seakeeping performance of the deep-V hybrid monohull is improved by a wide margin in contrast to that of the round bilge model, and there is a marked difference between the motion characteristics of large-scale vessel models in the coastal wave environment and that of small-scale vessel models in tank
A seven-gene signature predicts overall survival of patients with colorectal cancer
Colorectal cancer (CRC) is a major cause of global cancer mortality. Gene expression profiles can help predict prognosis of patients with CRC. In most of previous studies, disease recurrence was analyzed as the survival endpoint. Thus we aim to build a robust gene signature for prediction of overall survival (OS) in patients with CRC. Fresh frozen CRC tissues from 64 patients were analyzed using Affymetrix HG-U133plus 2.0 gene arrays. By performing univariate survival analysis, 6487 genes were found to be associated with the OS in our cohort. KEGG analysis revealed that these genes were mainly involved in pathways such as endocytosis, axon guidance, spliceosome, Wnt signalling and ubiquitin mediated proteolysis. A seven-gene signature was further selected by a robust likelihood-based survival modelling approach. The prognostic model of seven-gene signature (NHLRC3, ZDHHC21, PRR14L, CCBL1, PTPRB, PNPO, and PPIP5K2) was constructed and weighted by regression coefficient, which divided patients into high- and low-risk groups. The OS for patients in high-risk group was significantly poorer compared with patients in low-risk group. Moreover, all seven genes were found to be differentially expressed in CRC tissues as compared with adjacent normal tissues, indicating their potential role in CRC initiation and progression. This seven-gene signature was further validated as an independent prognostic marker for OS prediction in patients with CRC in other two independent cohorts. In short, we developed a robust seven-gene signature that can predict the OS for CRC patients, providing new insights into identification of CRC patients with high risk of mortality
3′,6′-Bis(diethylamino)-2-phenylspiro[isoindoline-1,9′-xanthen]-3-one
The title compound, C34H35O2N3, was synthesized by the reaction of 2-[3,6-bis(diethylamino)-9H-xanthen-9-yl]benzoyl chloride with aniline. In the molecular structure, the dihedral angles between the isoindoline and xanthene planes and between the isoindoline and benzene planes are 86.9 (3) and 47.0 (2)°, respectively. The molecular packing in the crystal structure is stabilized by weak C—H⋯O hydrogen bonding
Effects of Radiation Reabsorption on the Laminar Flame Speed and NO Emission during Aviation Kerosene Combustion at Elevated Pressures
Increasing attention has been paid on combustion stability and pollution emission of aviation kerosene due to the emerging interests on supersonic combustion scramjets. Whereas the vitiation component H2O introduced by hydrogen-fueled heaters in high-enthalpy vitiated air during ground experiments has a considerable influence on kerosene combustion, especially through its radiation effect, which needs to be further investigated. In this paper, the radiation reabsorption effects on laminar flame speeds and NO emissions during RP-3/H2O/O2/N2 combustion was assessed numerically over a wide range of equivalence ratio and pressure (ϕ = 0.7–1.4 and P = 1–15 atm) using detailed chemical and radiation models. The surrogate model of RP-3 consisted of vol. 25% 1,3,5-trimethylbenzene (C9H12), 46.31% n-decane (C10H22) and 28.69% iso-dodecane (IC12H26), while the vitiated air had 12% H2O. It was revealed that the radiation reabsorption of H2O in the vitiated air had significant impact on the accurate simulation of laminar flame speeds. As equivalence ratios varied, the role of radiation reabsorption on laminar flame speeds was most pronounced at ϕ = 0.7. As the key radical, the generation of H through the reversed step of CH2OH + H = CH3 + OH was chemically inhibited due to radiation. The radiation reabsorption effect on flame speeds was strengthened with rising pressures, with the reaction H + O2 = O + OH dominant at the pressure range 1–10 atm. In contrast, a slight increase in the impact on laminar flame speeds between 10 and 15 atm was controlled by direct radiative effect. Finally, for NO emission, the reduction of downstream temperature caused by radiative heat loss and the increment of radical concentrations induced by preheating determined radiation reabsorption effects on NO generation
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