331 research outputs found

    Analytical Methods Inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry (ICP-oa-TOF-MS) analysis of heavy metal content in Indocalamus tesselatus samples

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    a b s t r a c t Indocalamus tesselatus is one of the most popular packing materials in China. Heavy metals in Chinese I. tesselatus samples have received great interest because they are related to health. A simple and fast method for the determination of Pb, Cd, Mn, Ni, Cr, As, Hg, Cu and Zn, by inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry (ICP-oa-TOF-MS), following microwave closed vessel digestion of samples, was proposed. The method was validated using standard reference material (GBW 07605-Tea). Samples of I. tesselatus from five different regions of China were analysed using the proposed method. Heavy metals contents from different regions were found at different levels. Their low contents of heavy metals showed that collection areas were not polluted and all collected I. tesselatus samples could be unreservedly used as food packing materials without any health risk

    Construction of sterile system of Buchloe dactyloides (Nutt.) Engelm.

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    The stems of male and female strains of Bison grass (Buchloe dactyloides (Nutt.) Engelm.) were taken as explants, and 1 / 2MS and MS medium were used, and different concentrations of NAA, KT and 6-BA were added to study the rapid propagation technology of ferison grass. Results indicated that 75% alcohol was treated for 30s with another 0.1 g ꞏL-1The disinfection effect of mercury solution for 12 min; The MS + 1.5 mg ꞏL-1 NAA + 0.4 mg ꞏL-1 KT female strain showed the best induction effect, The MS + 1.5 mg ꞏL-1 NAA + 0.6 mg ꞏL-1 KT male strain had the best induction effect; 1 / 2 MS + 2 mg + L-1 NAA + 1.5 mg ꞏL-1 6-BA the female and male strains had the best proliferation effect; The highest number of roots and root root rate of 1 / 2 MS + 1.5 mg ꞏL-1 female and male NAA strains were combined

    Photocatalytic Hydrogen Generation from Water‐Annealed TiO2 Nanotubes with White and Grey Modification

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    Abstract In recent years, photocatalytic reactions on anodic TiO2 nanotubes have been intensively investigated. In order to show photocatalytic activity, anodically formed nanotubes need to be crystallized to anatase. This is conventionally done by thermal annealing in air at temperatures 400–600 °C. Recently, a so‐called “water annealing” treatment has been reported to be effective to also create a highly active form for photocatalysis. Here we report on the feasibility of using a water annealing treatment of TiO2 nanotubes to create a photocatalyst for H2 production that is as active as conventional thermal annealing. If the water‐annealed samples are additionally hydrogenated to a so‐called “grey” modification, a further significant improvement of the photocatalytic activity for H2 evolution can be achieved – this without the use of any noble metal co‐catalyst. A combination of water annealing, thermal annealing, followed by hydrogenation can deliver a H2 generation activity that is more than five times higher than that achieved by thermal annealing of anodic TiO2 nanotubes

    Genome-wide identification and expression analysis of the KCS gene family in soybean (Glycine max) reveal their potential roles in response to abiotic stress

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    Very long chain fatty acids (VLCFAs) are fatty acids with chain lengths of 20 or more carbon atoms, which are the building blocks of various lipids that regulate developmental processes and plant stress responses. 3-ketoacyl-CoA synthase encoded by the KCS gene is the key rate-limiting enzyme in VLCFA biosynthesis, but the KCS gene family in soybean (Glycine max) has not been adequately studied thus far. In this study, 31 KCS genes (namely GmKCS1 - GmKCS31) were identified in the soybean genome, which are unevenly distributed on 14 chromosomes. These GmKCS genes could be phylogenetically classified into seven groups. A total of 27 paralogous GmKCS gene pairs were identified with their Ka/Ks ratios indicating that they had undergone purifying selection during soybean genome expansion. Cis-acting element analysis revealed that GmKCS promoters contained multiple hormone- and stress-responsive elements, indicating that GmKCS gene expression levels may be regulated by various developmental and environmental stimuli. Expression profiles derived from RNA-seq data and qRT-PCR experiments indicated that GmKCS genes were diversely expressed in different organs/tissues, and many GmKCS genes were found to be differentially expressed in the leaves under cold, heat, salt, and drought stresses, suggesting their critical role in soybean resistance to abiotic stress. These results provide fundamental information about the soybean KCS genes and will aid in their further functional elucidation and exploitation

    LHCb upgrade software and computing : technical design report

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    This document reports the Research and Development activities that are carried out in the software and computing domains in view of the upgrade of the LHCb experiment. The implementation of a full software trigger implies major changes in the core software framework, in the event data model, and in the reconstruction algorithms. The increase of the data volumes for both real and simulated datasets requires a corresponding scaling of the distributed computing infrastructure. An implementation plan in both domains is presented, together with a risk assessment analysis

    Physics case for an LHCb Upgrade II - Opportunities in flavour physics, and beyond, in the HL-LHC era

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    The LHCb Upgrade II will fully exploit the flavour-physics opportunities of the HL-LHC, and study additional physics topics that take advantage of the forward acceptance of the LHCb spectrometer. The LHCb Upgrade I will begin operation in 2020. Consolidation will occur, and modest enhancements of the Upgrade I detector will be installed, in Long Shutdown 3 of the LHC (2025) and these are discussed here. The main Upgrade II detector will be installed in long shutdown 4 of the LHC (2030) and will build on the strengths of the current LHCb experiment and the Upgrade I. It will operate at a luminosity up to 2×1034 cm−2s−1, ten times that of the Upgrade I detector. New detector components will improve the intrinsic performance of the experiment in certain key areas. An Expression Of Interest proposing Upgrade II was submitted in February 2017. The physics case for the Upgrade II is presented here in more depth. CP-violating phases will be measured with precisions unattainable at any other envisaged facility. The experiment will probe b → sl+l−and b → dl+l− transitions in both muon and electron decays in modes not accessible at Upgrade I. Minimal flavour violation will be tested with a precision measurement of the ratio of B(B0 → μ+μ−)/B(Bs → μ+μ−). Probing charm CP violation at the 10−5 level may result in its long sought discovery. Major advances in hadron spectroscopy will be possible, which will be powerful probes of low energy QCD. Upgrade II potentially will have the highest sensitivity of all the LHC experiments on the Higgs to charm-quark couplings. Generically, the new physics mass scale probed, for fixed couplings, will almost double compared with the pre-HL-LHC era; this extended reach for flavour physics is similar to that which would be achieved by the HE-LHC proposal for the energy frontier

    Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

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    Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a ZZ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 <pT<100< p_{\textrm{T}} < 100 GeV and in the pseudorapidity range 2.5<η<42.5 < \eta < 4. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb1^{-1}. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

    Study of the BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

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    The decay BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} is studied in proton-proton collisions at a center-of-mass energy of s=13\sqrt{s}=13 TeV using data corresponding to an integrated luminosity of 5 fb1\mathrm{fb}^{-1} collected by the LHCb experiment. In the Λc+K\Lambda_{c}^+ K^{-} system, the Ξc(2930)0\Xi_{c}(2930)^{0} state observed at the BaBar and Belle experiments is resolved into two narrower states, Ξc(2923)0\Xi_{c}(2923)^{0} and Ξc(2939)0\Xi_{c}(2939)^{0}, whose masses and widths are measured to be m(Ξc(2923)0)=2924.5±0.4±1.1MeV,m(Ξc(2939)0)=2938.5±0.9±2.3MeV,Γ(Ξc(2923)0)=0004.8±0.9±1.5MeV,Γ(Ξc(2939)0)=0011.0±1.9±7.5MeV, m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV}, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt Λc+K\Lambda_{c}^{+} K^{-} sample. Evidence of a new Ξc(2880)0\Xi_{c}(2880)^{0} state is found with a local significance of 3.8σ3.8\,\sigma, whose mass and width are measured to be 2881.8±3.1±8.5MeV2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV} and 12.4±5.3±5.8MeV12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}, respectively. In addition, evidence of a new decay mode Ξc(2790)0Λc+K\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-} is found with a significance of 3.7σ3.7\,\sigma. The relative branching fraction of BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} with respect to the BD+DKB^{-} \to D^{+} D^{-} K^{-} decay is measured to be 2.36±0.11±0.22±0.252.36 \pm 0.11 \pm 0.22 \pm 0.25, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

    Structural characterizations of three-dimensional crimped silk yarns

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    Silk yarns which are composed of two single yarns with different twist directions are treated with calcium nitrate solution at 95 °C, and a 3-D crimped structure is formed. The Fourier transform infrared spectroscopy spectrum is used to reveal the change of the secondary structures of silk fiber

    Structural characterizations of three-dimensional crimped silk yarns

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