Accreting matter around clusters of galaxies: One-dimensional considerations

During the formation of large-scale structure in the Universe, matter accretes on to high-density peaks. Accreting collisionless dark matter (DM) forms caustics around them, while accreting collisional baryonic matter (BM) forms accretion shocks. The properties of the accreting matter depend upon the power spectrum of the initial perturbations on a given scale as well as the background expansion in a given cosmological model. In this paper, we have calculated the accretion of DM particles in one-dimensional spherical geometry under various cosmological models including the Einstein-de Sitter universe, the open universe with Omega(0) < 1, and the flat universe with Omega(A) = 1 - Omega(0). A density parameter in the range 0.1 less than or equal to Omega(0) less than or equal to 1 has been considered. The initial perturbation characterized by a point mass at the origin has been considered. Since the accretion shock of BM is expected to form close to the first caustic of DM, the properties of the accreting BM are common with those of the DM. Hence, the accretion calculations with DM particles have been used to find the position and velocity of the accretion shock and the cluster mass inside it. The average temperature of BM has been estimated by adopting simplifying assumptions. The velocity of the accreting BM around clusters of a given temperature is lower in a universe with lower Omega(0), but only by up to similar to 24 per cent in the models with 0.1 less than or equal to Omega(0) less than or equal to 1. Thus, it would be difficult to use that quantity to discriminate among the cosmological models. However, the accretion velocity around clusters of a given mass or a given radius depends more sensitively on the cosmological models. It is lower in a universe with lower Omega(0) by up to similar to 41 and similar to 65 per cent, respectively. So, it can provide a better signature of the background expansion for different cosmological models. Although the existence of the caustics and the accretion shocks may not be confirmed by direct X-ray observations, the infalling warm gas of 10(4)-10(5) K upstream of the shocks may be observed as the absorption systems of quasar emission lines. According to this study, the suggestion made by Kang, Ryu & Jones that the large-scale accretion shocks around clusters of galaxies can serve as possible acceleration sites of ultrahigh-energy cosmic rays above 10(18) eV remains plausible in all viable cosmological modelsopen131

Cosmic magnetic fields in large scale filaments and sheets

We consider the possibility that cosmic magnetic field, instead of being uniformly distributed, is strongly correlated with the large scale structure of the universe. Then, the observed rotational measure of extra-galactic radio sources would be caused mostly by the clumpy magnetic field in cosmological filaments/sheets rather than by a uniform magnetic field, which was often assumed in previous studies. As a model for the inhomogeneity of the cosmological magnetic field, we adopt a cosmological hydrodynamic simulation, where the field is passively included, and can approximately represent the real field distribution with an arbitrary normalization for the field strength. Then, we derive an upper limit of the magnetic field strength by comparing the observed limit of rotational measure with the rotational measure expected from the magnetic field geometry in the simulated model universe. The resulting upper limit to the magnetic field in filaments and sheets is (B) over bar(fs) less than or similar to 1 mu G which is similar to 10(3) times higher than the previously quoted values. This value is close to, but larger than, the equipartition magnetic field strength in filaments and sheets. The amplification mechanism of the magnetic field to the above strength is uncertain. The implications of such a strength of the cosmic magnetic field are discussedopen15012

Epitope Mapping of Antibodies Suggests the Novel Membrane Topology of B-Cell Receptor Associated Protein 31 on the Cell Surface of Embryonic Stem Cells: The Novel Membrane Topology of BAP31

When located in the endoplasmic reticulum (ER) membrane, B-cell receptor associated protein 31 (BAP31) is involved in the export of secreted proteins from the ER to the plasma membrane. In a previous study, we generated two monoclonal antibodies (mAbs), 297-D4 and 144-A8, that bound to surface molecules on human embryonic stem cells (hESCs), but not to surface molecules on mouse embryonic stem cells (mESCs). Subsequent studies revealed that the mAbs recognized BAP31 on the surface of hESCs. To investigate the membrane topology of BAP31 on the cell surface, we first examined the epitope specificity of 297-D4 and 144-A8, as well as a polyclonal anti-BAP31 antibody (alpha-BAP31). We generated a series of GST-fused BAP31 mutant proteins in which BAP31 was serially deleted at the C-terminus. GST-fused BAP31 mutant proteins were then screened to identify the epitopes targeted by the antibodies. Both 297-D4 and 144-A8 recognized C-terminal residues 208-217, while alpha-BAP31 recognized C-terminal residues 165-246, of BAP31 on hESCs, suggesting that the C-terminal domain of BAP31 is exposed on the cell surface. The polyclonal antibody alpha-BAP31 bound to mESCs, which confirmed that the C-terminal domain of BAP31 is also exposed on the surface of these cells. Our results show for the first time the novel membrane topology of cell surface-expressed BAP31 as the extracellular exposure of the BAP31 C-terminal domain was not predicted from previous studies.published_or_final_versio

Molecular Characterization of Two Monoclonal Antibodies against the Same Epitope on B-Cell Receptor Associated Protein 31

published_or_final_versio

High capacity cathode materials for Li-S batteries

To enhance the stability of sulfur cathode for a high energy lithium-sulfur battery, sulfur-activated carbon (S-AC) composite was prepared by encapsulating sulfur into micropores of activated carbon using a solution-based processing technique. In the analysis using the prepared specimen of S-AC composite by the focused ion beam (FIB) technique, the elemental sulfur exists in a highly dispersed state inside the micropores of activated carbon, which has a large surface area and a narrow pore distribution. The S-AC composite was characterized through X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) method, selected area electron diffraction (SAED), energy dispersive X-ray spectrometry (EDX), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry analysis (TGA), and field emission scanning electron microscopy (FESEM). A lithium-sulfur cell using the S-AC composite has a high first discharge capacity over 800 mA h g -1 S even at a high current density such as 2C (3200 mA g -1 S) and has good cycleability around 500 mA h g-1 S discharge capacity at the 50th cycle at the same current density. © 2013 The Royal Society of Chemistry

Stepwise phosphorylation of p65 promotes NF-kappa B activation and NK cell responses during target cell recognition

NF-κB is a key transcription factor that dictates the outcome of diverse immune responses. How NF-κB is regulated by multiple activating receptors that are engaged during natural killer (NK)-target cell contact remains undefined. Here we show that sole engagement of NKG2D, 2B4 or DNAM-1 is insufficient for NF-κB activation. Rather, cooperation between these receptors is required at the level of Vav1 for synergistic NF-κB activation. Vav1-dependent synergistic signalling requires a separate PI3K-Akt signal, primarily mediated by NKG2D or DNAM-1, for optimal p65 phosphorylation and NF-κB activation. Vav1 controls downstream p65 phosphorylation and NF-κB activation. Synergistic signalling is defective in X-linked lymphoproliferative disease (XLP1) NK cells entailing 2B4 dysfunction and required for p65 phosphorylation by PI3K-Akt signal, suggesting stepwise signalling checkpoint for NF-κB activation. Thus, our study provides a framework explaining how signals from different activating receptors are coordinated to determine specificity and magnitude of NF-κB activation and NK cell responses

Nanosheet thickness-modulated MoS2 dielectric property evidenced by field-effect transistor performance

We report on the nanosheet-thickness effects on the performance of top-gate MoS2 field-effect transistors (FETs), which is directly related to the MoS2 dielectric constant. Our top-gate nanosheet FETs with 40 nm thin Al2O3 displayed at least an order of magnitude higher mobility than those of bottom-gate nanosheet FETs with 285 nm thick SiO2, benefiting from the dielectric screening by high-k Al2O3. Among the top-gate devices, the single-layered FET demonstrated the highest mobility of similar to 170 cm(2) V-1 s(-1) with 90 mV dec(-1) as the smallest subthreshold swing (SS) but the double-and triple-layered FETs showed only similar to 25 and similar to 15 cm(2) V-1 s(-1) respectively with the large SS of 0.5 and 1.1 V dec(-1). Such property degradation with MoS2 thickness is attributed to its dielectric constant increase, which could rather reduce the benefits from the top-gate high-k dielectric.open115353Nsciescopu

Business process modelling and visualisation to support e-government decision making: Business/IS alignment

© 2017 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/978-3-319-57487-5_4.Alignment between business and information systems plays a vital role in the formation of dependent relationships between different departments in a government organization and the process of alignment can be improved by developing an information system (IS) according to the stakeholders’ expectations. However, establishing strong alignment in the context of the eGovernment environment can be difficult. It is widely accepted that business processes in the government environment plays a pivotal role in capturing the details of IS requirements. This paper presents a method of business process modelling through UML which can help to visualise and capture the IS requirements for the system development. A series of UML models have been developed and discussed. A case study on patient visits to a healthcare clinic in the context of eGovernment has been used to validate the models

Quality control and beam test of GEM detectors for future upgrades of the CMS muon high rate region at the LHC

Gas Electron Multipliers (GEM) are a proven position sensitive gas detector technology which nowadays is becoming more widely used in High Energy Physics. GEMs offer an excellent spatial resolution and a high particle rate capability, with a close to 100% detection efficiency. In view of the high luminosity phase of the CERN Large Hadron Collider, these aforementioned features make GEMs suitable candidates for the future upgrades of the Compact Muon Solenoid (CMS) detector. In particular, the CMS GEM Collaboration proposes to cover the high-eta region of the muon system with large-area triple-GEM detectors, which have the ability to provide robust and redundant tracking and triggering functions. In this contribution, after a general introduction and overview of the project, the construction of full-size trapezoidal triple-GEM prototypes will be described in more detail. The procedures for the quality control of the GEM foils, including gain uniformity measurements with an x-ray source will be presented. In the past few years, several CMS triple-GEM prototype detectors were operated with test beams at the CERN SPS. The results of these test beam campaigns will be summarised

Targeting of highly conserved Dengue virus sequences with anti-Dengue virus trans-splicing group I introns

<p>Abstract</p> <p>Background</p> <p>Dengue viruses (DENV) are one of the most important viral diseases in the world with approximately 100 million infections and 200,000 deaths each year. The current lack of an approved tetravalent vaccine and ineffective insecticide control measures warrant a search for alternatives to effectively combat DENV. The <it>trans</it>-splicing variant of the <it>Tetrahymena thermophila </it>group I intron catalytic RNA, or ribozyme, is a powerful tool for post-transcriptional RNA modification. The nature of the ribozyme and the predictability with which it can be directed makes it a powerful tool for modifying RNA in nearly any cell type without the need for genome-altering gene therapy techniques or dependence on native cofactors.</p> <p>Results</p> <p>Several anti-DENV Group I <it>trans</it>-splicing introns (αDENV-GrpIs) were designed and tested for their ability to target DENV-2 NGC genomes <it>in situ</it>. We have successfully targeted two different uracil bases on the positive sense genomic strand within the highly conserved 5'-3' cyclization sequence (CS) region common to all serotypes of DENV with our αDENV-GrpIs. Our ribozymes have demonstrated ability to specifically <it>trans</it>-splice a new RNA sequence downstream of the targeted site <it>in vitro </it>and in transfected insect cells as analyzed by firefly luciferase and RT-PCR assays. The effectiveness of these αDENV-GrpIs to target infecting DENV genomes is also validated in transfected or transformed Aedes mosquito cell lines upon infection with unattenuated DENV-2 NGC.</p> <p>Conclusions</p> <p>Analysis shows that our αDENV-GrpIs have the ability to effectively <it>trans</it>-splice the DENV genome <it>in situ</it>. Notably, these results show that the αDENV-GrpI 9v1, designed to be active against all forms of Dengue virus, effectively targeted the DENV-2 NGC genome in a sequence specific manner. These novel αDENV-GrpI introns provide a striking alternative to other RNA based approaches for the transgenic suppression of DENV in transformed mosquito cells and tissues.</p