40 research outputs found

    Regulation of High-Temperature Stress Response by Small RNAs

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    Temperature extremes constitute one of the most common environmental stresses that adversely affect the growth and development of plants. Transcriptional regulation of temperature stress responses, particularly involving protein-coding gene networks, has been intensively studied in recent years. High-throughput sequencing technologies enabled the detection of a great number of small RNAs that have been found to change during and following temperature stress. The precise molecular action of some of these has been elucidated in detail. In the present chapter, we summarize the current understanding of small RNA-mediated modulation of high- temperature stress-regulatory pathways including basal stress responses, acclimation, and thermo-memory. We gather evidence that suggests that small RNA network changes, involving multiple upregulated and downregulated small RNAs, balance the trade-off between growth/development and stress responses, in order to ensure successful adaptation. We highlight specific characteristics of small RNA-based tem- perature stress regulation in crop plants. Finally, we explore the perspectives of the use of small RNAs in breeding to improve stress tolerance, which may be relevant for agriculture in the near future

    Finishing the euchromatic sequence of the human genome

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    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

    Equilibrium Model of Discrete Dynamic Supply Chain Network with Random Demand and Advertisement Strategy

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    The advertisement can increase the consumers demand; therefore it is one of the most important marketing strategies in the operations management of enterprises. This paper aims to analyze the impact of advertising investment on a discrete dynamic supply chain network which consists of suppliers, manufactures, retailers, and demand markets associated at different tiers under random demand. The impact of advertising investment will last several planning periods besides the current period due to delay effect. Based on noncooperative game theory, variational inequality, and Lagrange dual theory, the optimal economic behaviors of the suppliers, the manufactures, the retailers, and the consumers in the demand markets are modeled. In turn, the supply chain network equilibrium model is proposed and computed by modified project contraction algorithm with fixed step. The effectiveness of the model is illustrated by numerical examples, and managerial insights are obtained through the analysis of advertising investment in multiple periods and advertising delay effect among different periods

    High-Temperature-Annealed Multi-Walled Carbon Nanotubes as High-Performance Conductive Agents for LiNi<sub>0.5</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>O<sub>2</sub> Lithium-Ion Batteries

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    In this work, the high yield of MWNTs was prepared by chemical vapor deposition (CVD) method, followed by annealing at 2000–2800 °C, and the effects of high annealing temperature on metal impurities and defects in multi-walled carbon nanotubes (MWNTs) was explored. Furthermore, the annealed MWNTs were dispersed using a sand mill to make a conductive slurry, and finally the cathode LiNi0.5Co0.2Mn0.3O2 was added to the assembled batteries, and the application of MWNTs (slurry) as conductive agents in LiNi0.5Co0.2Mn0.3O2 (NCM) cathode materials by sand-mill dispersion on the performance of lithium-ion batteries was investigated. The results indicate that high temperature annealing can effectively remove the residual metal impurities from MWNTs and the defects in MWNTs gradually decreases as the temperature rises. In addition, 2 wt% of MWNTs (slurry) in LiNi0.5Co0.2Mn0.3O2 is sufficient to form an electronically conductive network; as a result, the electronic conductivity and the high rates performance of the LiNi0.5Co0.2Mn0.3O2 batteries were greatly improved. The LiNi0.5Co0.2Mn0.3O2 battery with MWNTs slurries annealed at 2200 ℃ as a conductive additive displays the highest initial discharge capacity of 173.16 mAh·g−1 at 0.1 C. In addition, after 100 cycles, a capacity retention of 95.8% at 0.5 C and a discharge capacity of 121.75 mAh·g−1 at 5 C were observed. The multi-walled carbon nanotubes used as conductive agents in LiNi0.5Co0.2Mn0.3O2 (NCM) cathode materials show excellent battery behaviors, which would provide a new insight for the development of high-performance novel conductive agents in lithium-ion batteries

    Determination and Evaluation of Heavy Metal Content of Freshwater Economic Fish in Northeast Guangdong

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    Concentrations of lead (Pb), cadmium (Cd), chromium (Cr), copper (Cu), zinc (Zn) and manganese (Mn) were measured in various organs (such as in liver and muscle) from 9 species of freshwater economic fishes which were collected from northeast area of Guangdong Province. The concentration of metals was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). Results showed that the levels of metals in hepatopancreas of the fishes were found in order of Zn>Pb>Cu>Hg>Cd, while in muscles were Zn>Cr>Pb>Mn>Cu>Cd. In general, the metals concentrations were significantly higher in liver samples than that in muscle samples. Based on the “pollution index of single factor”, the fishes, to one degree or another, were polluted by Pb, Cd, Cr, Cu and Zn, and pollution levels were mostly followed by Pb>Cd>Cr>Cu>Zn. The indexes of Pb and Cd tested in hepatopancreas of the fishes were in a majority exceeded the national safety criteria for food in China. What’s more, it was found that the contents of the heavy metals in fishes did not vary with the trophic level which they belong to. In summary, the fishes were polluted by Pb, Cd, Cr, Cu and Zn to some extent, which indicated that hidden danger of heavy metals pollution was present in ecological environment or safety in fishery production in the area

    Bose-fermi mixtures in a three-dimensional optical lattice

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    Using the dynamical mean-field theory and the Gutzwiller method, we study the Mott transition in Bose–Fermi mixtures confined in a three-dimensional optical lattice and analyze the effect of fermions on the coherence of bosons. We conclude that increasing fermion composition reduces bosonic coherence in the presence of strong Bose–Fermi interactions and under the condition of the integer filling factors for composite fermions, which consist of one fermion and one or more bosonic holes. Various phases of the mixtures have been demonstrated including phase separation of two species, coexisting regions of superfluid bosons and fermionic liquids, and Mott regions in the phase space spanned by the chemical potentials of the bosons and the fermions.Accepted versio

    Thermal Simulation Study on the Solidification Structure and Segregation of a Heavy Heat-Resistant Steel Casting

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    The prediction and controlling of the solidification structure and macro-segregation in heavy steel casting, which is usually produced in limited quantities, was a conundrum in the foundry field. In this work, the cooling and solidification processes of a 16 t CB2 ferritic heat-resistant steel (FHRS) valve casting were reproduced by studying the solidification behavior of three typical units through a thermal simulation method. The results indicate that the types of casting without chilling have the most uneven distribution of solutes and hardness, while those types of casting in which parts are solidified by chilling are much more uniform. The macro-segregation degrees of B, C, Nb, P, Cr, Mo, Si, V and Mn decrease gradually during heavy casting of CB2 ferritic heat-resistant steel. Of them, B, C, Nb, and P are solutes prone to segregation, and the maximum macro-segregation index of B can even reach 15. The macro-segregation tendencies of Cr, Mo, Si, V, and Mn are relatively small. Further studies on the last solidification portion of samples taken by electron microprobe reveal that large-sized precipitates such as MnS and NbxC are easily formed due to solute enrichment, and the sizes of these precipitates were distributed from dozens to hundreds of micrometers

    Hierarchical Porous Carbon Anode Materials Derived from Rice Husks with High Capacity and Long Cycling Stability for Sodium-Ion Batteries

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    Compared with the cathode materials, the research on the anode materials of the sodium-ion batteries has lagged behind. Therefore, development of the anode materials with high capacity, long life, and excellent rate properties is the key to unlocking the practical application for sodium-ion batteries. This study presents the preparation of hierarchical porous hard carbon as an active anode material from rice husks. The as-synthesized materials are characterized by X-ray diffraction, N-2 adsorption, Raman spectra, scanning electron microscopy and transmission electron microscopy. These porous hard carbon materials exhibit a high specific surface area and are promising for reversible sodium storage. Galvanostatic studies show that the specific initial capacities of all samples were in the range of 130-300 mA h g(-1) at a current density of 100 mA g(-1) between 0.01 V and 2.3 V. Compared to the other samples, the hard carbon materials prepared at 800 degrees C from rice husk (RHPC-800) can deliver a high reversible capacity of 274 mA h g(-1) at a current density of 25 mA g(-1), maintain a capacity of approximately 260 mA h g(-1), and retain 92.7 % of its capacity after 500 cycles. This excellent electrochemical performance of the as-prepared RHPC-800 material is attributed to the high specific surface area and low charge transfer resistance

    Anti-Food Allergic Compounds from Penicillium griseofulvum MCCC 3A00225, a Deep-Sea-Derived Fungus

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    Ten new (1–10) and 26 known (11–36) compounds were isolated from Penicillium griseofulvum MCCC 3A00225, a deep sea-derived fungus. The structures of the new compounds were determined by detailed analysis of the NMR and HRESIMS spectroscopic data. The absolute configurations were established by X-ray crystallography, Marfey’s method, and the ICD method. All isolates were tested for in vitro anti-food allergic bioactivities in immunoglobulin (Ig) E-mediated rat basophilic leukemia (RBL)-2H3 cells. Compound 13 significantly decreased the degranulation release with an IC50 value of 60.3 μM, compared to that of 91.6 μM of the positive control, loratadine

    Genetic diversity and population structure of indigenous chicken breeds in South China

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    A total of 587 individuals from 12 indigenous chicken breeds from South China and two commercial breeds were genotyped for 26 microsatellites to investigate the genetic diversity and population structure. All microsatellites were found to be polymorphic. The number of alleles per locus ranged from 5 to 36, with an average of 12.10 ± 7.00 (SE). All breeds, except White Recessive Rock, had high allelic polymorphism (>0.5). Higher genetic diversity was revealed in the indigenous chicken breeds rather than in the commercial breeds. Potential introgression from the commercial breeds into the indigenous chickens was also detected. The population structure of these indigenous chicken breeds could be explained by their geographical distribution, which suggested the presence of independent history of breed formation. Data generated in this study will provide valuable information to the conservation for indigenous chicken breeds in future
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