Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite

As China's first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band (1-250 keV) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 MeV. It was designed to perform pointing, scanning and gamma-ray burst (GRB) observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed. Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.Comment: 29 pages, 40 figures, 6 tables, to appear in Sci. China-Phys. Mech. Astron. arXiv admin note: text overlap with arXiv:1910.0443

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

High Rate of Genetic Recombination in Murine Leukemia Virus: Implications for Influencing Proviral Ploidy

A significant difference in the recombination rates between human immunodeficiency virus type 1 (HIV-1) and the gammaretroviruses was previously reported, with the former being 10 to 100 times more recombinogenic. It is possible that preferential copackaging of homodimers in the case of gammaretroviruses, like murine leukemia virus (MLV), led to the underestimation of their rates of recombination. To reexamine the recombination rates for MLV, experiments were performed to control for nonrandom copackaging of viral RNA, and it was found that MLV and HIV-1 exhibit similar crossover rates. The implications for control of proviral ploidy and preferential recombination during minus-strand DNA synthesis are discussed

Anti-ribosomal P protein antibodies and insomnia correlate with depression and anxiety in patients suffering from systemic lupus erythematosus

Objective: Anxiety and depression in patients with systemic lupus erythematosus (SLE) complicate clinical treatment and can seriously affect prognosis. The present study aims to investigate the effects of the anti-ribosomal P protein antibody (anti-RibP) in the peripheral blood and insomnia on the severity of anxiety and depression in case of SLE. The study compared both the results of the investigation on the objective perceptions of physicians concerning mood changes in patients with SLE and the results of self-rating scales that were completed by the enrolled patients. The conclusion of the comparation is used to determine the probability of the accurate detection of anxiety and depression by physicians. The study aims to assist in the early detection in clinical practice of abnormal emotions in patients with SLE and to summarize common clinical interventions for anxiety and depression. Method: The relationship between anxiety and depression was evaluated by the Zung self-rating anxiety/depression scale (SAS/SDS). Basic information (e.g., blood type, smoking history, drinking history, educational background, duration of illness), the insomnia severity index (ISI) results, and anti-RibP in the peripheral blood, were investigated in 107 patients with SLE in northeastern China to further analyze the correlation between the severity of depression and anti-RibP, together with the consistency between results of the questionnaire for physicians and the self-rating scale for patients. Results: Gender, smoking history, drinking history, educational background, and duration of illness were correlated with the SAS/SDS scores (P < 0.05). Family history had a significant effect on the SAS score (P = 0.031), while the SDS score was significantly correlated with blood type (P = 0.021). The ISI score was significantly and positively correlated with the SAS/SDS score (P < 0.001). The titer of anti-RibP showed a correlation with the SDS score (P < 0.05) but not with the SAS score (P = 0.198). The titer of anti-RibP was significantly higher in patients with major depression compared with those with no depression, patients with mild depression, and those with moderate depression (P < 0.001). Conclusion: Anxiety and depression in patients with SLE were correlated with sleeping, educational background, blood type, smoking history, and alcohol consumption. Although anti-RibP was not significantly correlated with anxiety, it indicated a significant correlation with major depression. Clinicians were more accurate in assessing anxiety compared with depression

Screening of Lactobacillus Fermentum from Piglets and Its Potential Probiotic Properties

【Objective】A strain of Lactobacillus fermentum was isolated from the feces of healthy piglets, and its probiotic properties were tested in order to provide references for its applications in livestock and poultry breeding.【Method】106 strains of lactic acid bacteria were isolated by using Rogosa SL medium, and one strain which was potential for feeding was preliminarily screened by gram staining, acid and bile salt tolerance tests. The probiotic ability of strain LF1, which was identified as L. fermentum LF1 by 16S rDNA sequencing, was evaluated, including its antagonistic activity (Escherichia coli K88, Staphylococcus aureus, Streptococcus suis, Salmonella, and Vibrio, etc.), tolerance to the stimulated acidic environment in stomach and bile acid, and adhesion to small intestinal epithelial cells.【Result】L. fermentum LF1 had strong tolerance to acid and bile salt, showing its strong probiotic potential. However, the LF1 strain showed low adhesion to pig intestinal epithelial cells. In terms of antagonism, the culture supernatant of L. fermentum LF1 inhibited the growth of many animal pathogens significantly.【Conclusion】L. fermentum LF1 had a good probiotics ability. After further experimental evaluation on animals, it can be used as a probiotic candidate strain for livestock and poultry breeding industry

Progress in Application of Functional Microorganisms in Ecological and Healthy Breeding

Antibiotic abuse and environmental pollution caused by animal husbandry has aroused extensive concern from the government and the industry. As a kind of efficient alternative to agricultural chemicals like hormones and antibiotics, functional microorganisms can enhance the comprehensive growth performance of animals and thus play a crucial role in ecological and healthy breeding. The use of functional microorganisms in animal breeding for eco-agriculture has been a key development pathway for achieving the objective of sustainable development. Functional microorganisms are used at the beginning, middle, and end of the entire breeding process. Functional microorganisms can effectively eliminate anti-nutritional factors from feed sources, increasing their utilization rate and nutritional value. Animals fed with functional microorganisms not only have balanced gut microbiota and intestinal homeostasis, but their immune system is also well regulated. Functional microorganisms can also control odor emissions and pathogens in the environment. Finally, functional microorganisms also play an important role in the bio-safety treatment and circular utilization of breeding wastes. This study provides references for the continued application and promotion of functional microorganisms in animal breeding by summarizing the progress of their application and related mechanisms in such areas as feed processing, intestinal health, breeding environmental control and waste treatment

Effect of Operating Head on Dynamic Behavior of a Pump–Turbine Runner in Turbine Mode

Pumped storage units improve the stability of the power grid, and the key component is the pump–turbine. A pump–turbine usually needs to start and shutdown frequently, and the operating head varies greatly due to changes in the water level of the reservoir, which makes the dynamic behavior of a pump–turbine runner extremely complex. This paper investigates the effects of operating head on the dynamic response characteristics of a pump–turbine runner in turbine mode. The flow characteristics of the pump–turbine at maximum head, rated head and minimum head are analyzed, and the dynamic response characteristic of the pump–turbine runner are numerically studied. The results show that operating head can affect the pressure pulsation and dynamic stress characteristics of the pump–turbine runner, but it has little effect on the frequency spectra. The conclusions of this paper intend to improve understanding of the effects of the operating head on the dynamic behavior of the pump–turbine runner, therefore providing a theoretical reference for safe and stable operation of the pump–turbine unit

Effect of Operating Head on Dynamic Behavior of a Pump&ndash;Turbine Runner in Turbine Mode

Pumped storage units improve the stability of the power grid, and the key component is the pump&ndash;turbine. A pump&ndash;turbine usually needs to start and shutdown frequently, and the operating head varies greatly due to changes in the water level of the reservoir, which makes the dynamic behavior of a pump&ndash;turbine runner extremely complex. This paper investigates the effects of operating head on the dynamic response characteristics of a pump&ndash;turbine runner in turbine mode. The flow characteristics of the pump&ndash;turbine at maximum head, rated head and minimum head are analyzed, and the dynamic response characteristic of the pump&ndash;turbine runner are numerically studied. The results show that operating head can affect the pressure pulsation and dynamic stress characteristics of the pump&ndash;turbine runner, but it has little effect on the frequency spectra. The conclusions of this paper intend to improve understanding of the effects of the operating head on the dynamic behavior of the pump&ndash;turbine runner, therefore providing a theoretical reference for safe and stable operation of the pump&ndash;turbine unit

Human Immunodeficiency Virus Type 1 Recombination: Rate, Fidelity, and Putative Hot Spots

Previously, we reported that human immunodeficiency virus type 1 (HIV-1) recombines approximately two to three times per genome per replication cycle, an extremely high rate of recombination given the relatively small genome size of HIV-1. However, a recombination hot spot involving sequence of nonretroviral origin was identified in the vector system utilized, raising the possibility that this hot spot skewed the rate of recombination, and the rate of recombination observed was an overestimation. To address this issue, an HIV-1-derived vector system was used to examine the rate of recombination between autologous HIV-1 sequences after restricting replication to a single cycle in the absence of this hot spot. Viral DNA and RNA were analyzed by a combination of the heteroduplex tracking assay, restriction enzyme analysis, DNA sequencing, and reverse transcription-PCR. The results indicate that HIV-1 undergoes recombination at a minimum rate of 2.8 crossovers per genome per cycle. Again, this is a very high rate given the small size of the HIV-1 genome. The results also suggested that there might be local hot spots of recombination at different locations throughout the genome since 13 of the 33 strand transfers identified by DNA sequencing shared the same site of recombination with one or two other clones. Furthermore, identification of crossover segments also allowed examination of mutations at the point of recombination, since it has been predicted from some studies of cell-free systems that mutations may occur with a frequency of 30 to 50% at crossover junctions. However, DNA sequence analysis of crossover junctions indicated that homologous recombination during viral replication was not particularly mutagenic, indicating that there are other factors or conditions not yet reproduced in cell-free systems which contribute to fidelity during retroviral recombination

Ni-based catalysts derived from Ni-Zr-Al ternary hydrotalcites show outstanding catalytic properties for low-temperature CO2 methanation

Developing Ni-based catalysts with high activity and stability in low-temperature methanation is necessary due to their sintering and coking at high temperatures. Here, we report our developed novel Ni-Zr-Al catalysts derived from Ni-Zr-Al ternary hydrotalcites synthesized by a hydrothermal process, followed by a reduction in hydrogen. Comparing with the Ni-Al catalyst derived from Ni-Al hydrotalcite and the commercial Ni-based catalyst, the Ni-Zr-Al catalysts show a remarkably higher low-temperature activity (210-270 degrees C) in CO2 methanation. Both the experimental and theoretical calculations confirmed the introduction of Zr into the Ni-Al binary hydrotalcite could generate synergetic effects between Ni and ZrO2, resulting in more surface oxygen vacancies, basic sites, and abundant mesopores. In-situ DRIFTS analysis showed the CO2 methanation to CH4 follows the intermediate formate route. This work provides a new theoretical understanding of CO2 activation and methanation, and a practical way to address the existing problem for Ni-based catalysts