164 research outputs found

    Responses and sensitivities of maize phenology to climate change from 1971 to 2020 in Henan Province, China.

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    Climate change affects many aspects of the physiological and biochemical processes of growing maize and ultimately its yield. A comprehensive climate suitability model is proposed that quantifies the effects of temperature, precipitation, solar radiation, and wind in different phenological stages of maize. It is calibrated using weather and yield data from China's Henan Province. The comprehensive suitability model showed the capability of correctly hindcasting observed temporal and spatial changes in maize phenology in response to climatic factors. The predicted yield based on the suitability model can well match the recorded field yield very well from 1971-2020. The results of correlation showed that the yields are more closely related to multi-weather factors, temperature and precipitation than to solar radiation and wind. The sensitivity analysis illustrates that temperature and precipitation are the dominant weather factors affecting yield changes based on a direct differentiation method. The comprehensive suitability model can provide a scientific support and analysis tool for predicting grain production considering climate changes

    Inside-Out Radial Migration Facilitates Lineage-Dependent Neocortical Microcircuit Assembly

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    SummaryNeocortical excitatory neurons migrate radially along the glial fibers of mother radial glial progenitors (RGPs) in a birth-date-dependent inside-out manner. However, the precise functional significance of this well-established orderly neuronal migration remains largely unclear. Here, we show that strong electrical synapses selectively form between RGPs and their newborn progeny and between sister excitatory neurons in ontogenetic radial clones at the embryonic stage. Interestingly, the preferential electrical coupling between sister excitatory neurons, but not that between RGP and newborn progeny, is eliminated in mice lacking REELIN or upon clonal depletion of DISABLED-1, which compromises the inside-out radial neuronal migration pattern in the developing neocortex. Moreover, increased levels of Ephrin-A ligand or receptor that laterally disperse sister excitatory neurons also disrupt preferential electrical coupling between radially aligned sister excitatory neurons. These results suggest that RGP-guided inside-out radial neuronal migration facilitates the initial assembly of lineage-dependent precise columnar microcircuits in the neocortex

    MLVA distribution characteristics of Yersinia pestis in China and the correlation analysis

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    <p>Abstract</p> <p>Background</p> <p><it>Yersinia pestis</it>, the aetiological agent of plague, has been well defined genotypically on local and worldwide scales. In November 2005, five cases of severe pneumonia of unknown causes, resulting in two deaths, were reported in Yulong, Yunnan province. In this study, we compared <it>Y. pestis </it>isolated from the Yulong focus to strains from other areas.</p> <p>Results</p> <p>Two hundred and thirteen <it>Y. pestis </it>strains collected from different plague foci in China and a live attenuated vaccine strain of <it>Y. pestis </it>(EV76) were genotyped using multiple-locus variable-number tandem repeat analysis (MLVA) on 14 loci. A total of 214 <it>Y. pestis </it>strains were divided into 85 MLVA types, and Nei's genetic diversity indices of the various loci ranged between 0.02 - 0.76. Minimum spanning tree analysis showed that <it>Y. pestis </it>in China could be divided into six complexes. It was observed that Microtus strains were different from the other three biovar strains. Each plague focus had its own unique MLVA types.</p> <p>Conclusion</p> <p>The strains isolated from Yulong, Yunnan province had a unique MLVA type, indicating a new clone group. Our results suggest that Yulong strains may have a close relationship with strains from the Qinghai-Tibet Plateau plague focus.</p

    Isolation and Functional Determination of SKOR Potassium Channel in Purple Osier Willow, Salix purpurea.

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    Potassium (K+) plays key roles in plant growth and development. However, molecular mechanism studies of K+ nutrition in forest plants are largely rare. In plants, SKOR gene encodes for the outward rectifying Shaker-type K+ channel that is responsible for the long-distance transportation of K+ through xylem in roots. In this study, we determined a Shaker-type K+ channel gene in purple osier (Salix purpurea), designated as SpuSKOR, and determined its function using a patch clamp electrophysiological system. SpuSKOR was closely clustered with poplar PtrSKOR in the phylogenetic tree. Quantitative real-time PCR (qRT-PCR) analyses demonstrated that SpuSKOR was predominantly expressed in roots, and expression decreased under K+ depletion conditions. Patch clamp analysis via HEK293-T cells demonstrated that the activity of the SpuSKOR channel was activated when the cell membrane voltage reached at -10 mV, and the channel activity was enhanced along with the increase of membrane voltage. Outward currents were recorded and induced in response to the decrease of external K+ concentration. Our results indicate that SpuSKOR is a typical voltage dependent outwardly rectifying K+ channel in purple osier. This study provides theoretical basis for revealing the mechanism of K+ transport and distribution in woody plants.Peer Reviewe

    TBR2 coordinates neurogenesis expansion and precise microcircuit organization via Protocadherin 19 in the mammalian cortex.

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    Cerebral cortex expansion is a hallmark of mammalian brain evolution; yet, how increased neurogenesis is coordinated with structural and functional development remains largely unclear. The T-box protein TBR2/EOMES is preferentially enriched in intermediate progenitors and supports cortical neurogenesis expansion. Here we show that TBR2 regulates fine-scale spatial and circuit organization of excitatory neurons in addition to enhancing neurogenesis in the mouse cortex. TBR2 removal leads to a significant reduction in neuronal, but not glial, output of individual radial glial progenitors as revealed by mosaic analysis with double markers. Moreover, in the absence of TBR2, clonally related excitatory neurons become more laterally dispersed and their preferential synapse development is impaired. Interestingly, TBR2 directly regulates the expression of Protocadherin 19 (PCDH19), and simultaneous PCDH19 expression rescues neurogenesis and neuronal organization defects caused by TBR2 removal. Together, these results suggest that TBR2 coordinates neurogenesis expansion and precise microcircuit assembly via PCDH19 in the mammalian cortex

    Review and prospect of coal rock hydraulic fracturing physical experimental research

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    Physical simulation of hydraulic fracturing is an approximate representation of fracture evolution and its dynamic process, which represents an important direction of fracture evolution research. Similarity theory is the theoretical basis of the transformation between field prototype and experimental model. Test equipment and similar materials are the material premise of physical simulation experiment. Monitoring and detection technology is the key part to evaluate the fracturing effect of hydraulic fracturing. This paper summarizes the development of similarity theory of hydraulic fracturing physical experiments, the evolution of experimental materials and devices, and the characteristics and application scope of common monitoring and detection methods from the above three aspects. The analysis shows that: the similarity criterion of hydraulic fracturing has been preliminarily formed, but it needs to be further modified according to the physical and mechanical properties of coal and rock. Numerical simulation method can be used to explore the influence degree of minor factors ignored in the derivation of similarity criterion, so as to improve the reliability and applicability of the empirical equation. In view of various physical and mechanical properties of coal and rock, many empirical formula equations of similar materials have been obtained at present, but a set of detailed experimental specification and a large number of experimental attempts are still needed to improve the repeatability of the experiments, so as to establish a more universal database of empirical equations of similar material matching. Fracturing devices are developing towards the direction of multi-field coupling with more simulation conditions, larger simulation scale and wider simulation range, and fracturing methods are gradually diversified with engineering applications. However, the accuracy of triaxial loading of fracturing devices needs to be further improved to ensure effective fracturing experiments under high stress conditions, and reduce the impact of experimental operations on the final results. Monitoring methods and detection technologies have their own advantages in evaluating the fracturing effect of hydraulic fracturing, and similar materials also have a significant impact on the effectiveness and accuracy of monitoring methods and detection technologies. How to rationally select and combine monitoring methods and detection technologies based on experiments is the key to meet the research needs of micro-structures

    Transient Receptor Potential V Channels Are Essential for Glucose Sensing by Aldolase and AMPK

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    Fructose-1,6-bisphosphate (FBP) aldolase links sensing of declining glucose availability to AMPK activation via the lysosomal pathway. However, how aldolase transmits lack of occupancy by FBP to AMPK activation remains unclear. Here, we show that FBP-unoccupied aldolase interacts with and inhibits endoplasmic reticulum (ER)-localized transient receptor potential channel subfamily V, inhibiting calcium release in low glucose. The decrease of calcium at contact sites between ER and lysosome renders the inhibited TRPV accessible to bind the lysosomal v-ATPase that then recruits AXIN:LKB1 to activate AMPK independently of AMP. Genetic depletion of TRPVs blocks glucose starvation-induced AMPK activation in cells and liver of mice, and in nematodes, indicative of physical requirement of TRPVs. Pharmacological inhibition of TRPVs activates AMPK and elevates NAD(+) levels in aged muscles, rejuvenating the animals' running capacity. Our study elucidates that TRPVs relay the FBP-free status of aldolase to the reconfiguration of v-ATPase, leading to AMPK activation in low glucose

    Mixed Adjustment Algorithm for Part of the Coefficient Matrix with Uncertainty

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    Uncertainty often exists in the process of measurement data acquiring,which affects the reliability and validity of parameter estimation.Based on uncertain mixed adjustment model,this paper applies the adjustment criterion,minimizing the sum of squares of random error and squares of uncertainty error,to study a new iteration algorithm to solve the adjustment model under the bound constrain of uncertainty.By the example,the estimation results of proposed method are compared with that of another relative method.The results show that the parameter calculation method presented in this paper is effective and feasible.Meanwhile,the method has satisfied applicability when the uncertainty is large
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