1-(2,4-Dinitro­phen­yl)-3,3-dinitro­azetidine

In the title compound, C9H7N5O8, the dihedral angle between the mean plane of the azetidine ring and that of the benzene ring is 26.1 (1)°; the planes of the two nitro groups of the azetidine ring are aligned at 88.7 (1)°

Visualizing the elongated vortices in γ\gamma-Ga nanostrips

We study the magnetic response of superconducting $\gamma$-Ga via low temperature scanning tunneling microscopy and spectroscopy. The magnetic vortex cores rely substantially on the Ga geometry, and exhibit an unexpectedly-large axial elongation with aspect ratio up to 40 in rectangular Ga nano-strips (width $l$ $<$ 100 nm). This is in stark contrast with the isotropic circular vortex core in a larger round-shaped Ga island. We suggest that the unusual elongated vortices in Ga nanostrips originate from geometric confinement effect probably via the strong repulsive interaction between the vortices and Meissner screening currents at the sample edge. Our finding provides novel conceptual insights into the geometrical confinement effect on magnetic vortices and forms the basis for the technological applications of superconductors.Comment: published in Phys. Rev. B as a Rapid Communicatio

1-Benzoyl-3,3-dinitro­azetidine

In the title gem-dinitro­azetidine derivative, C10H9N3O5, the azetidine ring is almost planar, the maximum value of the endocyclic torsion angle being 0.92 (14)°. The gem-dinitro groups are mutually perpendicular and the dihedral angle between the azetidine and benzene rings is 46.70 (10)

Continuous twin screw rheo-extrusion of an AZ91D magnesium alloy

© The Minerals, Metals & Materials Society and ASM International 2012The twin screw rheo-extrusion (TSRE) is designed to take advantage of the nondendritc microstructure and thixotropic characterization of semisolid-metal slurries and produce simple metal profiles directly from melts. The extrusion equipment consists of a rotor-stator high shear slurry maker, a twin screw extruder, and a die assembly. The process is continuous and has a potential for significantly saving energy, manufacturing cost, and enhancing efficiency. The present investigation was carried out to study the process performance for processing rods of an AZ91D magnesium alloy and the microstructure evolution during processing. The semisolid slurry prepared by the process was characterized by uniformly distributed nondendritic granular primary phase particles. AZ91D rods with uniform and fine microstructures and moderate mechanical properties were produced. For the given slurry making parameters, decreasing extrusion temperature was found to improve microstructures and properties. The mechanisms of particle granulation and refinement and the effect of processing parameters on process performance and thermal management are discussed. © 2012 The Minerals, Metals & Materials Society and ASM International.EPSRC (UK) and Rautomead Lt

Detection of a superconducting phase in a two-atom layer of hexagonal Ga film grown on semiconducting GaN(0001)

The recent observation of superconducting state at atomic scale has motivated the pursuit of exotic condensed phases in two-dimensional (2D) systems. Here we report on a superconducting phase in two-monolayer crystalline Ga films epitaxially grown on wide band-gap semiconductor GaN(0001). This phase exhibits a hexagonal structure and only 0.552 nm in thickness, nevertheless, brings about a superconducting transition temperature Tc as high as 5.4 K, confirmed by in situ scanning tunneling spectroscopy, and ex situ electrical magneto-transport and magnetization measurements. The anisotropy of critical magnetic field and Berezinski-Kosterlitz-Thouless-like transition are observed, typical for the 2D superconductivity. Our results demonstrate a novel platform for exploring atomic-scale 2D superconductor, with great potential for understanding of the interface superconductivity

Vascular differentiation of multipotent spermatogonial stem cells derived from neonatal mouse testis

We previously reported the successful establishment of embryonic stem cell (ESC)-like multipotent spermatogonial stem cells (mSSCs) from neonatal mouse testis. Here, we examined the ability of mSSCs to differentiate into vascular endothelial cells and smooth muscle cells, and compared to that of mouse ESCs. We used real-time reverse transcriptase polymerase chain reaction and immunohistochemistry to examine gene expression profiles of mSSCs and ESCs during in vitro vascular differentiation. Both mSSCs and ESCs exhibited substantial increase in the expression of mesodermal markers, such as Brachyury, Flk1, Mesp1, Nkx2.5, and Islet1, and a decrease in the expression of pluripotency markers, such as Oct3/4 and Nanog during the early stage of differentiation. The mRNA levels of vascular endothelial (VE)-cadherin and CD31 gradually increased in both differentiated mSSCs and ESCs. VE-cadherin- or CD31-positive cells formed sprouting branch-like structures, as observed during embryonic vascular development. At the same time, vascular smooth muscle cell-specific markers, such as myocardin and α-smooth muscle actin (SMA), were also highly expressed in differentiated mSSCs and ESCs. Immunocytochemical analysis revealed that the differentiated cells expressed both α-SMA and SM22-α proteins, and exhibited the intracellular fibril structure typical of smooth muscle cells. Overall, our findings showed that mSSCs have similar vascular differentiation abilities to those of ESCs, suggesting that mSSCs may be an alternative source of autologous pluripotent stem cells for vascular regeneration

Screening immune adjuvants for an inactivated vaccine against Erysipelothrix rhusiopathiae

In this study, we screened adjuvants for an inactivated vaccine against Erysipelothrix rhusiopathiae (E. rhusiopathiae). Inactivated cells of E. rhusiopathiae strain HG-1 were prepared as the antigen in five adjuvanted inactivated vaccines, including a mineral-oil-adjuvanted vaccine (Oli vaccine), aluminum-hydroxide-gel-adjuvanted vaccine (Alh vaccine), ISA201-biphasic-oil-emulsion-adjuvanted vaccine (ISA201 vaccine), GEL02-water-soluble-polymer-adjuvanted vaccine (GEL vaccine), and IMS1313-water-soluble-nanoparticle-adjuvanted vaccine (IMS1313 vaccine). The safety test results of subcutaneous inoculation in mice showed that Oli vaccine had the most severe side effects, with a combined score of 35, followed by the ISA201 vaccine (25 points), Alh vaccine (20 points), GEL vaccine (10 points), and IMS1313 vaccine (10 points). A dose of 1.5LD50 of strain HG-1 was used to challenge the mice intraperitoneally, 14 days after their second immunization. The protective efficacy of Oli vaccine and Alh vaccine was 100% (8/8), whereas that of the other three adjuvanted vaccines was 88% (7/8). Challenge with 2.5LD50 of strain HG-1 resulted in a 100% survival rate, demonstrating the 100% protective efficacy of the Oli vaccine, followed by the GEL vaccine (71%, 5/7), IMS1313 vaccine (57%, 4/7), ISA201 vaccine (43%, 3/7), and Alh vaccine (29%, 2/7). Challenge with 4LD50 of strain HG-1 showed 100% (7/7) protective efficacy of the Oli vaccine and 71% (5/7) protective efficacy of the GEL vaccine, whereas the protective efficacy of other three adjuvanted vaccine was 14% (1/7). The Alh and GEL vaccines were selected for comparative tests in piglets, and both caused minor side effects. A second immunization with these two adjuvanted vaccines conferred 60 and 100% protective efficacy, respectively, after the piglets were challenged via an ear vein with 8LD100 of strain HG-1. After challenge with 16LD100 of strain HG-1, the Alh and GEL vaccines showed 40% and 100% protective efficacy, respectively. Our results suggested that GEL is the optimal adjuvant for an inactivated vaccine against E. rhusiopathiae

HDAC2 Negatively Regulates Memory Formation and Synaptic Plasticity

Chromatin modifications, especially histone-tail acetylation, have been implicated in memory formation. Increased histone-tail acetylation induced by inhibitors of histone deacetylases (HDACis) facilitates learning and memory in wild-type mice as well as in mouse models of neurodegeneration. Harnessing the therapeutic potential of HDACis requires knowledge of the specific HDAC family member(s) linked to cognitive enhancement. Here we show that neuron-specific overexpression of HDAC2, but not that of HDAC1, decreased dendritic spine density, synapse number, synaptic plasticity and memory formation. Conversely, Hdac2 deficiency resulted in increased synapse number and memory facilitation, similar to chronic treatment with HDACis in mice. Notably, reduced synapse number and learning impairment of HDAC2-overexpressing mice were ameliorated by chronic treatment with HDACis. Correspondingly, treatment with HDACis failed to further facilitate memory formation in Hdac2-deficient mice. Furthermore, analysis of promoter occupancy revealed an association of HDAC2 with the promoters of genes implicated in synaptic plasticity and memory formation. Taken together, our results suggest that HDAC2 functions in modulating synaptic plasticity and long-lasting changes of neural circuits, which in turn negatively regulates learning and memory. These observations encourage the development and testing of HDAC2-selective inhibitors for human diseases associated with memory impairment