362 research outputs found

    Homogeneous bubble nucleation limit of mercury under the normal working conditions of the planned European Spallation Source

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    In spallation neutron sources, liquid mercury is the subject of big thermal and pressure shocks, upon adsorbing the proton beam. These changes can cause unstable bubbles in the liquid, which can damage the structural material. While there are methods to deal with the pressure shock, the local temperature shock cannot be avoided. In our paper we calculated the work of the critical cluster formation (i.e. for mercury micro-bubbles) together with the rate of their formation (nucleation rate). It is shown that the homogeneous nucleation rates are very low even after adsorbing several proton pulses, therefore the probability of temperature induced homogeneous bubble nucleation is negligible.Comment: 22 Pages, 11 figures, one of them is colour, we plan to publish it in Eur. Phys. J.

    Effect Of Ridge-lap Surface Treatments On The Bond Of Resin Teeth To Denture Base.

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    To test in vitro the shear bond strength of resin teeth to an acrylic resin denture base given different ridgelap surface treatments. Ninety rectangular dies were made with wax and traditionally invested in metallic or plastic flasks. The stone molds were covered with silicone, in which were included an acrylic molar with a wax stick fixed on the ridge lap surface. After deflasking, the wax sticks were removed, the teeth were cleaned with detergent, the ridge lap surface was submitted to different treatments (unmodified, bur-cut grooves, aluminum oxide particle sandblasting, monomer swelling, and primer swelling), and the teeth were replaced in the silicone molds. Metallic flasks were placed in a thermopolymerizing unit to polymerize heat-curing denture-base polymer, and plastic flasks were placed in a domestic microwave oven at 900 W to polymerize microwaveable denture base polymer. After deflasking, the specimens were submitted to the shear bond test in an Instron machine at a cross-speed of 1 mm/min. Results were submitted to ANOVA and Tukey's test (5%). Shear bond strength values were influenced by the ridge-lap surface treatments only in the microwaved polymer. Sandblasting + monomer swelling and sandblasting + primer swelling interactions yielded lower strengths for microwaved polymer. Only the unmodified surfaces presented a significant difference when the resins were compared, where the microwaved polymer showed a higher value. Different tooth ridge-lap surface treatments promoted different strengths of the tooth/resin bond.13287-9

    Effect of water deficit and sowing date on oil and protein contents in soybean co-inoculated with Azospirillum brasilense.

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    The soybean chemical composition is strongly influenced by genetic factors, as well as their interaction with the environment and management practices. Among the environmental factors, water deficit and temperature are those that most contribute to modify the chemical composition of beans, especially oil and protein contents. The present study aimed to assess the effects of co-inoculation with Azospirillum brasilense on soybean oil and protein contents. Two field experiments were carried out on different sowing dates. The design consisted of randomized blocks, in a split-split-plot arrangement, with four replications, including two irrigation depths (25 % and 100 % of the ETc), two inoculation methods [Bradyrhizobium japonicum (strainsSemia 5079 and Semia 5080) and Azospirillum brasilense (strains AbV5 and AbV6 + Bradyrhizobium japonicum)] and two cultivars (ANTA 82 and TMG 132). The co-inoculation did not affect the oil and protein contents of beans for any of the assessed management conditions. The water deficit in the reproductive stage, combined with the sowing dates, altered the oil and protein contents in both the assessed cultivars, showing, respectively, a higher average protein and oil content in the beans for the cultivars TMG 132 and ANTA 82

    Novel nucleosomal particles containing core histones and linker DNA but no histone H1

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    Eukaryotic chromosomal DNA is assembled into regularly spaced nucleosomes, which play a central role in gene regulation by determining accessibility of control regions. The nucleosome contains ∼147 bp of DNA wrapped ∼1.7 times around a central core histone octamer. The linker histone, H1, binds both to the nucleosome, sealing the DNA coils, and to the linker DNA between nucleosomes, directing chromatin folding. Micrococcal nuclease (MNase) digests the linker to yield the chromatosome, containing H1 and ∼160 bp, and then converts it to a core particle, containing ∼147 bp and no H1. Sequencing of nucleosomal DNA obtained after MNase digestion (MNase-seq) generates genome-wide nucleosome maps that are important for understanding gene regulation. We present an improved MNase-seq method involving simultaneous digestion with exonuclease III, which removes linker DNA. Remarkably, we discovered two novel intermediate particles containing 154 or 161 bp, corresponding to 7 bp protruding from one or both sides of the nucleosome core. These particles are detected in yeast lacking H1 and in H1-depleted mouse chromatin. They can be reconstituted in vitro using purified core histones and DNA. We propose that these \u27proto-chromatosomes\u27 are fundamental chromatin subunits, which include the H1 binding site and influence nucleosome spacing independently of H1

    Magneto-optical properties of MnBiAl thin films

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    Mn-Bi-Al thin films. were produced by sequential evaporation of the constituents, followed by an anneal at 300 °C. The temperature and composition dependencies of the Kerr rotation angle, absolute reflectivity, and magnetic anisotropy were measured. The results show that, up to 30 at. % Al concentration, the thin films retain the pure MnBi hexagonal structure. Further, for suitable Al content, the films have the same large Kerr rotation as MnBi. Pure MnBi films exhibit perpendicular anisotropy at room temperature and in-plane anisotropy for temperatures below 142 K. In contrast,. the Al-doped films prepared here have perpendicular anisotropy down to at least 85 K. The increased coercivities of the Al-doped films are attributed to the occupation of grain-boundary and interstitial sites of the NiAs-type hexagonal structure by the Al-atoms

    Low immunogenicity of LNP allows repeated administrations of CRISPR-Cas9 mRNA into skeletal muscle in mice

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    筋ジストロフィーのゲノム編集治療を目指したLNP-mRNA輸送システムの開発. 京都大学プレスリリース. 2021-12-08.Nanotechnology for genome editing in multiple muscles simultaneously. 京都大学プレスリリース. 2021-12-08.Genome editing therapy for Duchenne muscular dystrophy (DMD) holds great promise, however, one major obstacle is delivery of the CRISPR-Cas9/sgRNA system to skeletal muscle tissues. In general, AAV vectors are used for in vivo delivery, but AAV injections cannot be repeated because of neutralization antibodies. Here we report a chemically defined lipid nanoparticle (LNP) system which is able to deliver Cas9 mRNA and sgRNA into skeletal muscle by repeated intramuscular injections. Although the expressions of Cas9 protein and sgRNA were transient, our LNP system could induce stable genomic exon skipping and restore dystrophin protein in a DMD mouse model that harbors a humanized exon sequence. Furthermore, administration of our LNP via limb perfusion method enables to target multiple muscle groups. The repeated administration and low immunogenicity of our LNP system are promising features for a delivery vehicle of CRISPR-Cas9 to treat skeletal muscle disorders

    Informações técnicas para o cultivo da BRS Tropical no Estado do Tocantins.

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    Em atendimento a uma demanda dos produtores de arroz tocantinenses por cultivares de arroz com características para alta produtividade, qualidade de grãos e tolerância à doenças, a Embrapa disponibiliza a BRS Tropical. Essa cultivar desenvolvida pelo programa de melhoramento de arroz irrigado é adaptada às condições tropicais, apresentando alto potencial produtivo e características agronômicas e culinárias adequadas para cultivo no sistema de irrigação por inundação nas regiões produtoras de arroz do estadobitstream/item/113876/1/Cotec222.pd
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