HUBS: Hot Universe Baryon Surveyor Cui, W.; Chen, L.-B.; Gao, B. ...
Journal of low temperature physics,
04/2020, Letnik:
199, Številka:
1-2
Journal Article
Recenzirano
Hot Universe Baryon Surveyor (HUBS) is proposed in China as a major X-ray mission for the next decade. It is designed to be highly focused scientifically, with two primary objectives: (1) detecting ...X-ray emission from hot baryons in intergalactic medium and circumgalactic medium (CGM), and characterizing their physical and chemical properties; (2) studying, based on the observations, the accretion and feedback processes that are thought to be highly relevant to the heating and chemical enrichment of the baryons in the CGM. Because of very low densities, the signal is expected to be very weak and thus technically difficult to detect. On the other hand, the spectrum of the emission is expected to be line rich, so it would be effective for detecting the hot baryons in bright emission lines. For that, an instrument with high spectral resolution, large effective area and large field of view (FoV) would be required. HUBS will couple a TES-based X-ray imaging spectrometer to a large FoV X-ray telescope to satisfy these requirements. A preliminary design of HUBS is presented.
Abstract
Knowledge of magnetic symmetry is vital for exploiting nontrivial surface states of magnetic topological materials. EuIn
2
As
2
is an excellent example, as it is predicted to have collinear ...antiferromagnetic order where the magnetic moment direction determines either a topological-crystalline-insulator phase supporting axion electrodynamics or a higher-order-topological-insulator phase with chiral hinge states. Here, we use neutron diffraction, symmetry analysis, and density functional theory results to demonstrate that EuIn
2
As
2
actually exhibits low-symmetry helical antiferromagnetic order which makes it a stoichiometric magnetic topological-crystalline axion insulator protected by the combination of a 180
∘
rotation and time-reversal symmetries:
$${C}_{2}\times {\mathcal{T}}={2}^{\prime}$$
C
2
×
T
=
2
′
. Surfaces protected by
$${2}^{\prime}$$
2
′
are expected to have an exotic gapless Dirac cone which is unpinned to specific crystal momenta. All other surfaces have gapped Dirac cones and exhibit half-integer quantum anomalous Hall conductivity. We predict that the direction of a modest applied magnetic field of
μ
0
H
≈ 1 to 2 T can tune between gapless and gapped surface states.
We compared the effects of salt-stresses (SS, 1: 1 molar ratio of NaCl to Na₂SO₄) and alkali-stresses (AS, 1: 1 molar ratio of NaHCO₃ to Na₂CO₃) on the growth, photosynthesis, solute accumulation, ...and ion balance of barley seedlings, to elucidate the mechanism of AS (high-pH) damage to plants and the physiological adaptive mechanism of plants to AS. The effects of SS on the water content, root system activity, membrane permeability, and the content of photosynthetic pigments were much less than those of AS. However, AS damaged root function, photosynthetic pigments, and the membrane system, led to the severe reductions in water content, root system activity, content of photosynthetic pigments, and net photosynthetic rate, and a sharp increase in electrolyte leakage rate. Moreover, with salinity higher than 60 mM, Na⁺ content increased slowly under SS and sharply under AS. This indicates that high-pH caused by AS might interfere with control of Na⁺ uptake in roots and increase intracellular Na⁺ to a toxic level, which may be the main cause of some damage emerging under higher AS. Under SS, barley accumulated organic acids, Cl⁻, SO₄ ²⁻, and NO₃ ⁻ to balance the massive influx of cations, the contribution of inorganic ions to ion balance was greater than that of organic acids. However, AS might inhibit absorptions of NO₃ ⁻ and Cl⁻, enhance organic acid synthesis, and SO₄ ²⁻ absorption to maintain intracellular ion balance and stable pH.
Aberrant activation of c-kit proto-oncogene contributes to abnormal cell proliferation by altering the tyrosine kinase signaling and constitutes a crucial impetus for leukemogenesis. Epigenetic ...silencing of tumor-suppressive microRNAs (miRNAs) is a key oncogenic mechanism for the activation of oncogenes in tumors. In this study, several miRNAs potentially binding to the 3'-untranslated region of human c-kit mRNA were screened by luciferase reporter assays. Among these miRNAs, miR-193a was embedded in a CpG island and epigenetically repressed by promoter hypermethylation in acute myeloid leukemia (AML) cell lines and primary AML blasts, but not in normal bone marrow cells. Importantly, miR-193a levels were inversely correlated with c-kit levels measured in 9 leukemia cell lines and 27 primary AML samples. Restoring miR-193a expression in AML cells harboring c-kit mutation and/or overexpression, either by synthetic miR-193a transfection or by DNA hypomethylating agent 5-azacytidine (5-aza) treatment, resulted in a significant reduction in c-kit expression at both RNA and protein levels and inhibition of cell growth. The growth-inhibitory activity of miR-193a was associated with apoptosis and granulocytic differentiation. Moreover, 5-aza-induced c-kit reduction could be partially blocked by miR-193a inhibitor, leading to a reversal of antiproliferative and proapoptotic effects of 5-aza. These data reveal a critical role for methylation-repressed miR-193a in myeloid leukemogenesis and the therapeutic promise of upregulating miR-193a expression for c-kit-positive AML.
•We observed that in the early stage of COVID-19, C-reactive protein levels can reflect the extent of lung lesions and disease severity.•It provides an important clinical evaluation index.•CRP levels ...can reflect disease changes, especially for patients who are not suitable to be referred to other facilities or patients in critical condition.
COVID-19 is a new infectious disease, for which there is currently no treatment. It is therefore necessary to explore biomarkers to determine the extent of lung lesions and disease severity.
We aimed to assess the usefulness of CRP levels in the early stage of COVID-19 and to correlate them with lung lesions and severe presentation.
Confirmed cases of COVID-19 were selected at the Fever Unit in two regions of Guizhou, China. On admission CRP levels were collected, and the diameter of the largest lung lesion was measured in the most severe lung lesion by lung CT scan. Differences in the diameter and CRP levels were compared in the following groups of patients: mild group, moderate group, severe group, and critical group.
CRP levels and the diameter of the largest lung lesion in the moderate group were higher than those in the mild group (Mann-Whitney test=−2.647, −2.171, P˂0.05), those in the severe group were higher than those in the moderate group (Mann-Whitney test=0.693, −2.177, P˂0.05), and those in the critical group were higher than those in the severe group (Mann-Whitney test=−0.068, −1.549, P˂0.05). The difference was statistically significant. CRP levels were positively correlated with the diameter of lung lesion and severe presentation (correlation coefficient=0.873, 0.734, P˂0.001).
In the early stage of COVID-19 CRP levels were positively correlated with lung lesions and could reflect disease severity.
An 8‐week feeding trial was conducted to establish the dietary vitamin E requirement of juvenile cobia. The basal diet was supplemented with 10, 20, 30, 40, 60, 120 mg vitamin E kg−1 as ...all‐rac‐α‐tocopheryl acetate. The results indicated that fish fed the diets supplemented vitamin E had significantly higher specific growth rate, protein efficiency ratio, feed efficiency and survival rate than those fed the basal diet. It was further observed that vitamin E concentrations in liver increased significantly when the dietary vitamin E level increased from 13.2 to 124 mg kg−1. Fish fed the basal diet had significantly higher thiobarbituric acid‐reactive substances concentrations in liver than those fed the diets supplemented vitamin E. Fish fed the diets supplemented with 45.7 and 61.2 mg kg−1 vitamin E had significantly higher red blood cell and haemoglobin than those fed the basal diet, while fish fed the diets supplemented with 61.2 and 124 mg kg−1 vitamin E had higher immunoglobulin concentration than those fish fed the basal diet. Lysozyme and superoxide dismutase were significantly influenced by the dietary vitamin E level. The dietary vitamin E requirement of juvenile cobia was established based on second‐order polynomial regression of weight gain and lysozyme to be 78 or 111 mg all‐rac‐α‐tocopheryl acetate kg−1 diet, respectively.
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