504 research outputs found

    Radiative transitions in charmonium from Nf=2N_f=2 twisted mass lattice QCD

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    We present a study for charmonium radiative transitions: J/ψηcγJ/\psi\rightarrow\eta_c\gamma, χc0J/Ψγ\chi_{c0}\rightarrow J/\Psi\gamma and hcηcγh_c\rightarrow\eta_c\gamma using Nf=2N_f=2 twisted mass lattice QCD gauge configurations. The single-quark vector form factors for ηc\eta_c and χc0\chi_{c0} are also determined. The simulation is performed at a lattice spacing of a=0.06666a= 0.06666 fm and the lattice size is 323×6432^3\times 64. After extrapolation of lattice data at nonzero Q2Q^2 to 0, we compare our results with previous quenched lattice results and the available experimental values.Comment: typeset with revtex, 15 pages, 11 figures, 4 table

    The Wavelength-Locking of High-Power 808 nm Semiconductor Laser

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    A distributed feedback (DFB) laser of 808 nm is produced in this paper whose optical power is 2 W, cavity length is 3 mm, and injecting width is 200 μm. A second-order grating formed into an InGaP/GaAs/InGaP multilayer structure provides the optical distributed feedback. The holographic lithography method is adopted to make Bragg gratings in p-waveguide layer (Λ = 240 nm) of the GaAs epitaxial wafers. The best experimental conditions are determined by analyzing the surface morphology and three-dimensional holographic grating. In addition, the output power data and wavelength of the distributed feedback laser emitting at different temperatures are presented. And the wavelength varies with temperature at a rate of 0.062 nm/K. Finally, the conclusion is drawn that this kind of DFB laser has a better temperature stabilized wavelength and narrower line width

    Prediction of the potentially suitable areas of Ligularia virgaurea and Ligularia sagitta on the Qinghai–Tibet Plateau based on future climate change using the MaxEnt model

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    Ligularia virgaurea and Ligularia sagitta are two species of poisonous plants with strong invasiveness in natural grasslands in China that have caused considerable harm to animal husbandry and the ecological environment. However, little is known about their suitable habitats and the key environmental factors affecting their distribution. Although some studies have reported the distributions of poisonous plants on the Qinghai–Tibet Plateau (QTP) and predicted their potential distributions at local scales in some regions under climate change, there have been few studies on the widespread distributions of L. virgaurea and L. sagitta. In this study, we recorded 276 and 118 occurrence points of L. virgaurea and L. sagitta on the QTP using GPS, and then used the MaxEnt model to predict the distribution of suitable habitats. Results showed that (1) under current climate conditions, L. virgaurea and L. sagitta are mainly distributed in southern Gansu, eastern Qinghai, northwestern Sichuan, eastern Tibet, and southwestern Yunnan, accounting for approximately 34.9% and 39.8% of the total area of the QTP, respectively; (2) the main environmental variables affecting the distribution of suitable habitats for L. virgaurea and L. sagitta are the Human Footprint Index (52.8%, 42.2%), elevation (11%, 4.4%), soil total nitrogen (18.9%, 4.2%), and precipitation seasonality (5.1%, 7.3%); and (3) in the future, in the 2050s and 2070s, the area of habitat of intermediate suitability for L. virgaurea will spread considerably in northwest Sichuan, while that of high suitability for L. sagitta will spread to eastern Tibet and western Sichuan

    Cinnamaldehyde up-regulates the mRNA expression level of TRPV1 receptor potential ion channel protein and its function in primary rat DRG neurons in vitro

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    Cinnamaldehyde (1) is a pharmacologically active ingredient isolated from cassia twig (Ramulus Cinnamomi), which is commonly used in herbal remedies to treat fever-related diseases. Both TRPV1 and TRPM8 ion channel proteins are abundantly expressed in sensory neurons, and are assumed to act as a thermosensor, with the former mediating the feeling of warmth and the latter the feeling of cold in the body. Both of them have recently been reported to be involved in thermoregulation. The purpose of this paper is to further uncover the antipyretic mechanisms of 1 by investigating its effects on the mRNA expression levels and functions of both TRPV1 and TRPM8. The results showed that 1 could up-regulate the mRNA expression levels of TRPV1 at both 37 and 39 degrees C, and its calcium-mediating function was significantly increased at 39 degrees C, all of which could not be blocked by pretreatment of the neuronal cells with ruthenium red, a general transient receptor potential (TRP) blocker, indicating that the action of 1 was achieved through a non-TRPA1 channel pathway. In conclusion, the findings in our in vitro studies might account for part of the peripheral molecular mechanisms for the antipyretic action of 1

    Complete mitochondrial genomes of Taenia multiceps, T. hydatigena and T. pisiformis: additional molecular markers for a tapeworm genus of human and animal health significance

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    <p>Abstract</p> <p>Background</p> <p>Mitochondrial genomes provide a rich source of molecular variation of proven and widespread utility in molecular ecology, population genetics and evolutionary biology. The tapeworm genus <it>Taenia </it>includes a diversity of tapeworm parasites of significant human and veterinary importance. Here we add complete sequences of the mt genomes of <it>T. multiceps</it>, <it>T. hydatigena </it>and <it>T. pisiformis</it>, to a data set of 4 published mtDNAs in the same genus. Seven complete mt genomes of <it>Taenia </it>species are used to compare and contrast variation within and between genomes in the genus, to estimate a phylogeny for the genus, and to develop novel molecular markers as part of an extended mitochondrial toolkit.</p> <p>Results</p> <p>The complete circular mtDNAs of <it>T. multiceps</it>, <it>T. hydatigena </it>and <it>T. pisiformis </it>were 13,693, 13,492 and 13,387 bp in size respectively, comprising the usual complement of flatworm genes. Start and stop codons of protein coding genes included those found commonly amongst other platyhelminth mt genomes, but the much rarer initiation codon GTT was inferred for the gene <it>atp</it>6 in <it>T. pisiformis</it>. Phylogenetic analysis of mtDNAs offered novel estimates of the interrelationships of <it>Taenia</it>. Sliding window analyses showed <it>nad</it>6, <it>nad</it>5, <it>atp</it>6, <it>nad</it>3 and <it>nad</it>2 are amongst the most variable of genes per unit length, with the highest peaks in nucleotide diversity found in <it>nad</it>5. New primer pairs capable of amplifying fragments of variable DNA in <it>nad</it>1, <it>rrn</it>S and <it>nad</it>5 genes were designed <it>in silico </it>and tested as possible alternatives to existing mitochondrial markers for <it>Taenia</it>.</p> <p>Conclusions</p> <p>With the availability of complete mtDNAs of 7 <it>Taenia </it>species, we have shown that analysis of amino acids provides a robust estimate of phylogeny for the genus that differs markedly from morphological estimates or those using partial genes; with implications for understanding the evolutionary radiation of important <it>Taenia</it>. Full alignment of the nucleotides of <it>Taenia </it>mtDNAs and sliding window analysis suggests numerous alternative gene regions are likely to capture greater nucleotide variation than those currently pursued as molecular markers. New PCR primers developed from a comparative mitogenomic analysis of <it>Taenia </it>species, extend the use of mitochondrial markers for molecular ecology, population genetics and diagnostics.</p

    Chromosome-level assembly of Lindenbergia philippensis and comparative genomic analyses shed light on genome evolution in Lamiales

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    Lamiales, comprising over 23,755 species across 24 families, stands as a highly diverse and prolific plant group, playing a significant role in the cultivation of horticultural, ornamental, and medicinal plant varieties. Whole-genome duplication (WGD) and its subsequent post-polyploid diploidization (PPD) process represent the most drastic type of karyotype evolution, injecting significant potential for promoting the diversity of this lineage. However, polyploidization histories, as well as genome and subgenome fractionation following WGD events in Lamiales species, are still not well investigated. In this study, we constructed a chromosome-level genome assembly of Lindenbergia philippensis (Orobanchaceae) and conducted comparative genomic analyses with 14 other Lamiales species. L. philippensis is positioned closest to the parasitic lineage within Orobanchaceae and has a conserved karyotype. Through a combination of Ks analysis and syntenic depth analysis, we reconstructed and validated polyploidization histories of Lamiales species. Our results indicated that Primulina huaijiensis underwent three rounds of diploidization events following the γ-WGT event, rather than two rounds as reported. Besides, we reconfirmed that most Lamiales species shared a common diploidization event (L-WGD). Subsequently, we constructed the Lamiales Ancestral Karyotype (LAK), comprising 11 proto-chromosomes, and elucidated its evolutionary trajectory, highlighting the highly flexible reshuffling of the Lamiales paleogenome. We identified biased fractionation of subgenomes following the L-WGD event across eight species, and highlighted the positive impacts of non-WGD genes on gene family expansion. This study provides novel genomic resources and insights into polyploidy and karyotype remodeling of Lamiales species, essential for advancing our understanding of species diversification and genome evolution
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