6,965 research outputs found

    Expression of bgt gene in transgenic birch (Betula platyphylla Suk.)

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    Study on the characteristics of integration and expression is the basis of genetic stability of foreign genes in transgenic trees. To obtain insight into the relationship of transgene copy number and expression level, we screened 22 transgenic birch lines. Southern blot analysis of the transgenic birch plants indicated that the copy number of bgt varies from one to four, of which 18.2% were single copy. Copy number of bgt and gus was different in 68% of transgenic birch plants, indicating that rearrangement or partial deletion appeared in the process of T-DNA integration. Transcriptional expression of bgt gene in transgenic birch plants was analyzed by Northern blot. TGS has been found in two transgenic lines with one and four copies of bgt. The ELISA result showed that the BGT protein expression level in the transgenic birch plants ranged from 0.000 to 0.283% of total soluble protein. In contrary to most studies, this research showed no significant correlation was found between copy number and expression level of bgt gene. Effective resistance of transgenic plants against Lymantria dispar was verified in feeding bioassays with the insects. Bioassays results were mostly consistent with the expression level of BGT insecticidal protein detected by ELISA and Western blot in transgenic birch. The paper showed transgenic birch had the high lethal effect on gypsy moth larvae (L. dispar). The practicality of this work will benefit not only the birch producers, but also the environment worldwide

    Newton-Hooke Limit of Beltrami-de Sitter Spacetime, Principles of Galilei-Hooke's Relativity and Postulate on Newton-Hooke Universal Time

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    Based on the Beltrami-de Sitter spacetime, we present the Newton-Hooke model under the Newton-Hooke contraction of the BdSBdS spacetime with respect to the transformation group, algebra and geometry. It is shown that in Newton-Hooke space-time, there are inertial-type coordinate systems and inertial-type observers, which move along straight lines with uniform velocity. And they are invariant under the Newton-Hooke group. In order to determine uniquely the Newton-Hooke limit, we propose the Galilei-Hooke's relativity principle as well as the postulate on Newton-Hooke universal time. All results are readily extended to the Newton-Hooke model as a contraction of Beltrami-anti-de Sitter spacetime with negative cosmological constant.Comment: 25 pages, 3 figures; some misprints correcte

    The stability of transgene expression and effect of DNA methylation on post transcriptional gene silencing (PTGS) in birch

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    In this paper, we selected transgenic birch (Betula platyphylla Suk) plants, which included nonsilencing plants, transcriptional silence plants including TP96, TP74, TP73 and the post-transcriptional silence ones (TP67 and TP72). The transcription of the bgt gene in different tissues and organs were significantly different. The transcriptional level of bgt gene in the different tissues and organs was in the following order: leaf > female flower and male flower > branch bark > phloem > root. The transgenic lines were monitored for foreign gene expression for a long-term period of 8 years during their continuous growth under field conditions. GUS protein expression was not reactivated in the transgene silencing lines TP72 and TP67 when cultured in field conditions for long-term period. Meanwhile, no cases of gene silencing were observed again during the study period in the field conditions. Our results suggest that transgene expression in transgenic birch plants appears to be stable under field conditions. The frequencies of methylated cytosines in the code regions of gus gene was studied. Relation of transgene expression and DNA methylation was analysed. The data of restriction enzyme digestion (HpaII and MspI) indicated that DNA methylation resulted in post transcriptional gene silencing (PTGS) in transgenic birch.Key words: Transgenic birch, DNA methylation, gene silencing

    Mass Hierarchy Determination Using Neutrinos from Multiple Reactors

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    We report the results of Monte Carlo simulations of a medium baseline reactor neutrino experiment. The difference in baselines resulting from the 1 km separations of Daya Bay and Ling Ao reactors reduces the amplitudes of 1-3 oscillations at low energies, decreasing the sensitivity to the neutrino mass hierarchy. A perpendicular detector location eliminates this effect. We simulate experiments under several mountains perpendicular to the Daya Bay/Ling Ao reactors, considering in particular the background from the TaiShan and YangJiang reactor complexes. In general the hierarchy can be determined most reliably underneath the 1000 meter mountain BaiYunZhang, which is 44.5 km from Daya Bay. If some planned reactors are not built then nearby 700 meter mountains at 47-51 km baselines gain a small advantage. Neglecting their low overhead burdens, hills near DongKeng would be the optimal locations. We use a weighted Fourier transform to avoid a spurious dependence on the high energy neutrino spectrum and find that a neural network can extract quantities which determine the hierarchy marginally better than the traditional RL + PV.Comment: 22 pages, added details on the neural network (journal version

    A comprehensive study of the open cluster NGC 6866

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    We present CCD UBVRIUBVRI photometry of the field of the open cluster NGC 6866. Structural parameters of the cluster are determined utilizing the stellar density profile of the stars in the field. We calculate the probabilities of the stars being a physical member of the cluster using their astrometric data and perform further analyses using only the most probable members. The reddening and metallicity of the cluster were determined by independent methods. The LAMOST spectra and the ultraviolet excess of the F and G type main-sequence stars in the cluster indicate that the metallicity of the cluster is about the solar value. We estimated the reddening E(B−V)=0.074±0.050E(B-V)=0.074 \pm 0.050 mag using the U−BU-B vs B−VB-V two-colour diagram. The distance modula, the distance and the age of NGC 6866 were derived as μ=10.60±0.10\mu = 10.60 \pm 0.10 mag, d=1189±75d=1189 \pm 75 pc and t=813±50t = 813 \pm 50 Myr, respectively, by fitting colour-magnitude diagrams of the cluster with the PARSEC isochrones. The Galactic orbit of NGC 6866 indicates that the cluster is orbiting in a slightly eccentric orbit with e=0.12e=0.12. The mass function slope x=1.35±0.08x=1.35 \pm 0.08 was derived by using the most probable members of the cluster.Comment: 14 pages, including 16 figures and 7 tables, accepted for publication in MNRAS. Table 4 in the manuscript will be published electronicall

    The pseudokinase CaMKv is required for the activity-dependent maintenance of dendritic spines

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    Fabrication and characterization of complex coacervates utilizing gelatin and carboxymethyl starch

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    BackgroundModified polysaccharides have greatly expanded applications in comparison with native polysaccharides due to their improved compatibility and interactions with proteins and active compounds in food-related areas. Nonetheless, there is a noticeable dearth of research concerning the utilization of carboxymethyl starch (CMS) as a microcapsule wall material in food processing, despite its common use in pharmaceutical delivery. The development of an economical and safe embedding carrier using CMS and gelatin (GE) holds immense importance within the food-processing industry. In this work, the potential of innovative coacervates formed by the combination of GE and CMS as a reliable, stable, and biodegradable embedding carrier is evaluated by turbidity measurements, thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and rheological measurements.ResultsThe results indicate that GE-CMS coacervates primarily resulted from electrostatic interactions and hydrogen bonding. The optimal coacervation was observed at pH 4.6 and with a GE/CMS blend ratio of 3:1 (w/w). However, the addition of NaCl reduced coacervation and made it less sensitive to temperature changes (35–55 \ub0C). In comparison with individual GE or CMS, the coacervates exhibited higher thermal stability, as shown by TGA. X-ray diffraction analysis shows that the GE-CMS coacervates maintained an amorphous structure. Rheological testing reveals that the GE-CMS coacervates exhibited shear-thinning behavior and gel-like properties.ConclusionOverall, attaining electroneutrality in the mixture boosts the formation of a denser structure and enhances rheological properties, leading to promising applications in food, biomaterials, cosmetics, and pharmaceutical products. \ua9 2023 Society of Chemical Industry

    Geometries for Possible Kinematics

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    The algebras for all possible Lorentzian and Euclidean kinematics with so(3)\frak{so}(3) isotropy except static ones are re-classified. The geometries for algebras are presented by contraction approach. The relations among the geometries are revealed. Almost all geometries fall into pairs. There exists t↔1/(ν2t)t \leftrightarrow 1/(\nu^2t) correspondence in each pair. In the viewpoint of differential geometry, there are only 9 geometries, which have right signature and geometrical spatial isotropy. They are 3 relativistic geometries, 3 absolute-time geometries, and 3 absolute-space geometries.Comment: 40 pages, 7 figure

    Obvious enhancement of the total reaction cross sections for 27,28^{27,28}P with 28^{28}Si target and the possible relavent mechanisms

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    The reaction cross sections of 27,28^{27,28}P and the corresponding isotones on Si target were measured at intermediate energies. The measured reaction cross sections of the N=12 and 13 isotones show an abrupt increase at % Z=15. The experimental results for the isotones with Z≤14Z\leq 14 as well as % ^{28}P can be well described by the modified Glauber theory of the optical limit approach. The enhancement of the reaction cross section for 28^{28}P could be explained in the modified Glauber theory with an enlarged core. Theoretical analysis with the modified Glauber theory of the optical limit and few-body approaches underpredicted the experimental data of 27^{27}P. Our theoretical analysis shows that an enlarged core together with proton halo are probably the mechanism responsible for the enhancement of the cross sections for the reaction of 27^{27}P+28^{28}Si.Comment: 16 pages, 5 figures, to be published in Phys.Rev.

    Neutron scattering and muon-spin spectroscopy studies of the magnetic triangular-lattice compounds A2A_2La2_2NiW2_2O12_{12} (AA = Sr, Ba)

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    We report on the geometrically frustrated two-dimensional triangular-lattice magnets A2A_2La2_2NiW2_2O12_{12} (AA = Sr, Ba) studied mostly by means of neutron powder diffraction (NPD) and muon-spin rotation and relaxation (μ\muSR) techniques. The chemical pressure induced by the Ba-for-Sr substitution suppresses the ferromagnetic (FM) transition from 6.3 K in the Ba-compound to 4.8 K in the Sr-compound. We find that the R3ˉR\bar{3} space group reproduces the NPD patterns better than the previously reported R3ˉmR\bar{3}m space group. Both compounds adopt the same magnetic structure with a propagation vector k=(0,0,0)\boldsymbol{k} = (0, 0, 0), in which the Ni2+^{2+} magnetic moments are aligned ferromagnetically along the cc-axis. The zero-field {\textmu}SR results reveal two distinct internal fields (0.31 and 0.10 T), caused by the long-range ferromagnetic order. The small transverse muon-spin relaxation rates reflect the homogeneous internal field distribution in the ordered phase and, thus, further support the simple FM arrangement of the Ni2+^{2+} moments. The small longitudinal muon-spin relaxation rates, in both the ferromagnetic- and paramagnetic states of A2_2La2_2NiW2_2O12_{12}, indicate that spin fluctuations are rather weak. Our results demonstrate that chemical pressure indeed changes the superexchange interactions in A2A_2La2_2NiW2_2O12_{12} compounds, with the FM interactions being dominant.Comment: 8 pages, 7 figures; accepted by Phys. Rev. Material
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