80 research outputs found
Correction to Lagrangian for Bouncing Cosmologies in Gravity
Symmetric teleparallel gravity offers to reformulate the gravitational
formalism without the presence of curvature and torsion with the help of
non-metricity tensors. Interestingly, Symmetric teleparallel gravity can be
formulated equivalently to teleparallel gravity or general relativity for an
appropriate setup. In this study, our aim lies in exploring the bouncing
cosmologies as an alternative to the initial singularity of the Universe in the
background of modified symmetric teleparallel gravity. To explore this, we
adopt the reconstruction technique to present the possible reconstructed
Lagrangian for various cosmological bouncing solutions in a flat
Friedmann-Lema\^itre-Robertson-Walker spacetime with a perfect fluid matter
distribution. We study the reconstructed gravitational Lagrangians, which are
capable of reproducing analytical solutions for \textit{symmetric bounce},
\textit{super-bounce}, \textit{oscillatory bounce}, \textit{matter bounce}, and
\textit{exponential bouncing} model settings. Further, we examine the dark
energy profiles of the models using reconstructed Lagrangians. In addition, we
found that an additional term arises in each reconstructed Lagrangian compared
to general relativity (GR). That extra term corrected the background GR to
present bouncing cosmology in modified gravity. These newly motivated
cosmological models may have an effect on gravitational phenomena at other
cosmological scales.Comment: Comments are welcom
Cytoskeletal control of B cell responses to antigens.
The actin cytoskeleton is essential for cell mechanics and has increasingly been implicated in the regulation of cell signalling. In B cells, the actin cytoskeleton is extensively coupled to B cell receptor (BCR) signalling pathways, and defects of the actin cytoskeleton can either promote or suppress B cell activation. Recent insights from studies using single-cell imaging and biophysical techniques suggest that actin orchestrates BCR signalling at the plasma membrane through effects on protein diffusion and that it regulates antigen discrimination through the biomechanics of immune synapses. These mechanical functions also have a role in the adaptation of B cell subsets to specialized tasks during antibody responses
Polyethylene Glycol-Mediated Synthesis of Cubic Iron Oxide Nanoparticles with High Heating Power
International Journal of Pharma and Bio Sciences RESEARCH ARTICLE MEDICINAL CHEMISTRY SYNTHESIS, CHARACTERIZATIONAND BIOLOGICAL STUDIES OF 2-[(2-
A new Schiff base derived from 2-amino, 4-methyl phenol with 5-nitro salicylaldehyde (AMPNSA) and their Ti(IV) and Zr(IV) metal complexes. The metal chelates were characterized on the basis of infrared spectra, elemental analysis, electronic spectral data, conductance and 1 H NMR spectral analysis. The complexes confirm to 1:1 stoichiometry and are electrolyte in nature. The coordination of the ligand to the metal ions is found to be through azomethine nitrogen, phenoxide oxygen and phenolic – OH of the Schiff base in the octahedral environment. The Schiff base and its metal complexes have been tested for their antimicrobial activity using disc diffusion methods and the results discussed. This article can be downloaded from www.ijpbs.ne
THERMOELECTRIC PROPERTIES OF GRAPHENE-MESOPOROUS SEMICONDUCTOR NANOCOMPOSITE
International audienc
Complexes of Bacterial Nicotinate Mononucleotide Adenylyltransferase with Inhibitors: Implication for Structure-Based Drug Design and Improvement
Bacterial nicotinate mononucleotide adenylyltransferase encoded by the essential gene nadD plays a central role in the synthesis of the redox cofactor NAD(+). The NadD enzyme is conserved in the majority of bacterial species and has been recognized as a novel target for developing new and potentially broad-spectrum antibacterial therapeutics. Here we report the crystal structures of Bacillus anthracis NadD in complex with three NadD inhibitors, including two analogues synthesized in the present study. These structures revealed a common binding site shared by different classes of NadD inhibitors and explored the chemical environment surrounding this site. The structural data obtained here also showed that the subtle changes in ligand structure can lead to significant changes in the binding mode, information that will be useful for future structure-based optimization and design of high affinity inhibitors
Recommended from our members
The Bcl-2 repertoire of mesothelioma spheroids underlies acquired apoptotic multicellular resistance.
Three-dimensional (3D) cultures are a valuable platform to study acquired multicellular apoptotic resistance of cancer. We used spheroids of cell lines and actual tumor to study resistance to the proteasome inhibitor bortezomib in mesothelioma, a highly chemoresistant tumor. Spheroids from mesothelioma cell lines acquired resistance to bortezomib by failing to upregulate Noxa, a pro-apoptotic sensitizer BH3-only protein that acts by displacing Bim, a pro-apoptotic Bax/Bak-activator protein. Surprisingly, despite their resistance, spheroids also upregulated Bim and thereby acquired sensitivity to ABT-737, an inhibitor of anti-apoptotic Bcl-2 molecules. Analysis using BH3 profiling confirmed that spheroids acquired a dependence on anti-apoptotic Bcl-2 proteins and were 'primed for death'. We then studied spheroids grown from actual mesothelioma. ABT-737 was active in spheroids grown from those tumors (5/7, ∼70%) with elevated levels of Bim. Using immunocytochemistry of tissue microarrays of 48 mesotheliomas, we found that most (33, 69%) expressed elevated Bim. In conclusion, mesothelioma cells in 3D alter the expression of Bcl-2 molecules, thereby acquiring both apoptotic resistance and sensitivity to Bcl-2 blockade. Mesothelioma tumors ex vivo also show sensitivity to Bcl-2 blockade that may depend on Bim, which is frequently elevated in mesothelioma. Therefore, mesothelioma, a highly resistant tumor, may have an intrinsic sensitivity to Bcl-2 blockade that can be exploited therapeutically
- …