322 research outputs found

    Exogenous brassinosteroids alleviate calcium deficiency-induced tip-burn by maintaining cell wall structural stability and higher photosynthesis in mini Chinese Cabbage

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    Tip-burn has seriously affected the yield, quality and commodity value of mini Chinese cabbage. Calcium (Ca2+) deficiency is the main cause of tip-burn. In order to investigate whether exogenous brassinosteroids (BRs) can alleviate tip-burn induced by calcium (Ca2+) deficiency and its mechanism, in this study, Ca2+ deficiency in nutrient solution was used to induced tip-burn, and then distilled water and BRs were sprayed on leaves to observe the tip-burn incidence of mini Chinese cabbage. The tip-burn incidence and disease index, leaf area, fluorescence parameters (Fv/Fm, NPQ, qP andφPSII) and gas exchange parameters (Tr, Pn, Gs and Ci), pigment contents, cell wall components, mesophyll cell ultrastructure and the expression of genes related to chlorophyll degradation were measured. The results showed that exogenous BRs reduced the tip-burn incidence rate and disease index of mini Chinese cabbage, and the tip-burn incidence rate reached the highest on the ninth day after treatment. Exogenous BRs increased the contents of cellulose, hemifiber, water-soluble pectin in Ca2+ deficiency treated leaves, maintaining the stability of cell wall structure. In addition, BRs increased photosynthetic rate by increasing the activities of Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and fructose 1,6-bisphosphatase (FBPase) related to Calvin cycle, maintaining relatively complete chloroplast structure and higher chlorophyll content via down-regulating the expression of BrPPH1 and BrPAO1 genes related to chlorophyll degradation. In conclusion, exogenous BRs alleviated calcium deficiency-induced tip-burn by maintaining cell wall structural stability and higher photosynthesis

    Gobi agriculture: an innovative farming system that increases energy and water use efficiencies. A review

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    International audienceAbstractIn populated regions/countries with fast economic development, such as Africa, China, and India, arable land is rapidly shrinking due to urban construction and other industrial uses for the land. This creates unprecedented challenges to produce enough food to satisfy the increased food demands. Can the millions of desert-like, non-arable hectares be developed for food production? Can the abundantly available solar energy be used for crop production in controlled environments, such as solar-based greenhouses? Here, we review an innovative cultivation system, namely “Gobi agriculture.” We find that the innovative Gobi agriculture system has six unique characteristics: (i) it uses desert-like land resources with solar energy as the only energy source to produce fresh fruit and vegetables year-round, unlike conventional greenhouse production where the energy need is satisfied via burning fossil fuels or electrical consumption; (ii) clusters of individual cultivation units are made using locally available materials such as clay soil for the north walls of the facilities; (iii) land productivity (fresh produce per unit land per year) is 10–27 times higher and crop water use efficiency 20–35 times greater than traditional open-field, irrigated cultivation systems; (iv) crop nutrients are provided mainly via locally-made organic substrates, which reduce synthetic inorganic fertilizer use in crop production; (v) products have a lower environmental footprint than open-field cultivation due to solar energy as the only energy source and high crop yields per unit of input; and (vi) it creates rural employment, which improves the stability of rural communities. While this system has been described as a “Gobi-land miracle” for socioeconomic development, many challenges need to be addressed, such as water constraints, product safety, and ecological implications. We suggest that relevant policies are developed to ensure that the system boosts food production and enhances rural socioeconomics while protecting the fragile ecological environment

    Generation of integration-free neural progenitor cells from cells in human urine

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    Human neural stem cells hold great promise for research and therapy in neural disease. We describe the generation of integration-free and expandable human neural progenitor cells (NPCs). We combined an episomal system to deliver reprogramming factors with a chemically defined culture medium to reprogram epithelial-like cells from human urine into NPCs (hUiNPCs). These transgene-free hUiNPCs can self-renew and can differentiate into multiple functional neuronal subtypes and glial cells in vitro. Although functional in vivo analysis is still needed, we report that the cells survive and differentiate upon transplant into newborn rat brain.postprin

    TIR/BB-Loop Mimetic AS-1 Attenuates Cardiac Ischemia/Reperfusion Injury via a Caveolae and Caveolin-3-Dependent Mechanism

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    AS-1, the TIR/BB loop mimetic, plays a protective role in cardiac ischemia/reperfusion (I/R) but the molecular mechanism remains unclear. The muscle specific caveolin3 (Cav-3) and the caveolae have been found to be critical for cardioprotection. This study aimed to evaluate our hypothesis that caveolae and Cav-3 are essential for AS-1-induced cardioprotection against myocardial I/R injury. To address these issues, we analyzed the involvement of Cav-3 in AS-1 mediated cardioprotection both in vivo and in vitro. We demonstrate that AS-1 administration significantly decreased infarct size, improved cardiac function after myocardial I/R and modulated membrane caveolae and Cav-3 expression in the myocardium. For in vitro studies, AS-1 treatment prevented Cav-3 re-distribution induced by H/R injury. In contrast, disruption of caveolae by MCD treatment or Cav-3 knockdown abolished the protection against H/R-induced myocytes injury by AS-1. Our findings reveal that AS-1 attenuates myocardial I/R injury through caveolae and Cav-3 dependent mechanism

    Development and validation of a nomogram for differentiating immune checkpoint inhibitor-related pneumonitis from pneumonia in patients undergoing immunochemotherapy: a multicenter, real-world, retrospective study

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    BackgroundImmune Checkpoint Inhibitor-related Pneumonitis (CIP) exhibits high morbidity and mortality rates in the real world, often coexisting with pneumonia, particularly after immunochemotherapy. We aimed to develop and validate a non-invasive nomogram for differentiating CIP from pneumonia in patients undergoing immunochemotherapy.MethodsThis study encompassed 237 patients from three hospitals. A multivariate logistic regression analysis was conducted to identify risk factors for CIP. Utilizing the random forest machine learning method, optimal development and validation cohort allocation ratios (in a ratio of 8:2) were determined for the predictive model. The performance of the nomogram was evaluated using calibration, the area under the receiver operating characteristic curve (AUC), and decision curve analysis (DCA). Subsequently respiratory pathogens, management, and outcomes were compared between CIP and No CIP cases.ResultsAmong the 237 patients, 104 were diagnosed with CIP, and 133 were no CIP but pneumonia(No CIP). Smoking status, prior chronic obstructive pulmonary disease (COPD), ground glass opacities, non-specific interstitial pneumonitis, Neutrophil to Lymphocyte Ratio (NLR), pleural effusions, and Oxygen Partial Pressure (PaO2) emerged as non-invasive independent predictors of CIP. The nomogram exhibited good discrimination for both the development and validation cohorts, with AUC values of 0.817 (95% CI, 0.754–0.879) and 0.913 (95% CI, 0.826–0.999), respectively. The calibration curves demonstrated good fit for both the development and validation cohort, as evidenced by the Hosmer-Lemeshow tests (χ² = 3.939, p = 0.863 and χ² = 8.117, p = 0.422, respectively). DCA further highlighted their clinical utility. In CIP patients, the use of gamma globulin/albumin and glucocorticoids was significantly higher than in No CIP patients (39.4% vs 23.3%, p = 0.007; 79.8% vs 12.8%, p < 0.0001, respectively). The proportion of patients requiring mechanical ventilation was also significantly higher in the CIP compared to the No CIP group (21.2% vs 11.3%, p = 0.038).ConclusionThe nomogram offers a non-invasive approach to differentiate CIP from pneumonia associated with immunochemotherapy, potentially facilitating early intervention and informed treatment decisions

    Insight-HXMT observations of Swift J0243.6+6124 during its 2017-2018 outburst

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    The recently discovered neutron star transient Swift J0243.6+6124 has been monitored by {\it the Hard X-ray Modulation Telescope} ({\it Insight-\rm HXMT). Based on the obtained data, we investigate the broadband spectrum of the source throughout the outburst. We estimate the broadband flux of the source and search for possible cyclotron line in the broadband spectrum. No evidence of line-like features is, however, found up to 150 keV\rm 150~keV. In the absence of any cyclotron line in its energy spectrum, we estimate the magnetic field of the source based on the observed spin evolution of the neutron star by applying two accretion torque models. In both cases, we get consistent results with B1013 GB\rm \sim 10^{13}~G, D6 kpcD\rm \sim 6~kpc and peak luminosity of >1039 erg s1\rm >10^{39}~erg~s^{-1} which makes the source the first Galactic ultraluminous X-ray source hosting a neutron star.Comment: publishe

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

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    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
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