Gravitational GUT Breaking and the GUT-Planck Hierarchy

It is shown that non-renormalizable gravitational interactions in the Higgs sector of supersymmetric grand unified theories (GUT's) can produce the breaking of the unifying gauge group $G$ at the GUT scale $M_{\rm GUT} \sim 10^{16}$~GeV. Such a breaking offers an attractive alternative to the traditional method where the superheavy GUT scale mass parameters are added ad hoc into the theory. The mechanism also offers a natural explanation for the closeness of the GUT breaking scale to the Planck scale. A study of the minimal SU(5) model endowed with this mechanism is presented and shown to be phenomenologically viable. A second model is examined where the Higgs doublets are kept naturally light as Goldstone modes. This latter model also achieves breaking of $G$ at $M_{\rm GUT}$ but cannot easily satisfy the current experimental proton decay bound.Comment: 11 pages, REVTeX, 1 figure included as an uuencoded Z-compressed PostScript file. Our Web page at http://physics.tamu.edu/~urano/research/gutplanck.html contains ready to print PostScript version (with figures) as well as color version of plot

A calcium-dependent protease as a potential therapeutic target for Wolfram syndrome

Wolfram syndrome is a genetic disorder characterized by diabetes and neurodegeneration and considered as an endoplasmic reticulum (ER) disease. Despite the underlying importance of ER dysfunction in Wolfram syndrome and the identification of two causative genes, Wolfram syndrome 1 (WFS1) and Wolfram syndrome 2 (WFS2), a molecular mechanism linking the ER to death of neurons and β cells has not been elucidated. Here we implicate calpain 2 in the mechanism of cell death in Wolfram syndrome. Calpain 2 is negatively regulated by WFS2, and elevated activation of calpain 2 by WFS2-knockdown correlates with cell death. Calpain activation is also induced by high cytosolic calcium mediated by the loss of function of WFS1. Calpain hyperactivation is observed in the WFS1 knockout mouse as well as in neural progenitor cells derived from induced pluripotent stem (iPS) cells of Wolfram syndrome patients. A small-scale small-molecule screen targeting ER calcium homeostasis reveals that dantrolene can prevent cell death in neural progenitor cells derived from Wolfram syndrome iPS cells. Our results demonstrate that calpain and the pathway leading its activation provides potential therapeutic targets for Wolfram syndrome and other ER diseases

Low Temperature Symmetry of Pyrochlore Oxide Cd2Re2O7

We report the X-ray study for the pyrochlore oxide Cd2Re2O7. Two symmetry-lowering structural transitions were observed at Ts1=200K and Ts2=120K. The former is of the second order from the ideal cubic pyrochlore structure with space group Fd-3m to a tetragonally distorted structure with I-4m2, while the latter is of the first order likely to another tetragonal space group I4122. We discuss the feature of the lattice deformation.Comment: 4 pages, 4 figure

Biocompatibility of cross-linked hyaluronate (Gel-200) for the treatment of knee osteoarthritis

SummaryObjectiveTo compare the biocompatibility and immunogenicity of two intra-articular hyaluronan formulations, Gel-200 (Gel-One®) and hylan G-F 20 (Synvisc® series).Experimental designA comparison of the biocompatibility of Gel-200 and hylan G-F 20 was made using a rat subcutaneous air pouch model and the knee joint of normal rabbits. Immunogenicity was evaluated using a homologous passive cutaneous anaphylaxis (PCA) assay in guinea pigs.ResultsIn the air pouch model in rats, characteristic fibrous belts formed in the subcutaneous tissue. Injection of hylan G-F 20 into the air pouch induced granulomatous nodules primarily composed of macrophages, multinucleated giant cells, and eosinophils accompanied with the test material in the center of the nodules in the fibrous belt. Furthermore, the thickness of the fibrous belt in the hylan G-F 20 group increased significantly compared to the saline group. Injection of Gel-200 into the air pouch induced neither granulomatous inflammation nor significant thickening of fibrous belt, while foamy macrophages containing the test material were observed. Intra-articular injection of hylan G-F 20 into the rabbit knee joints induced granulomatous inflammation, eosinophil infiltration, and significant increase in the number of cells in the synovial fluid, while these findings were absent in the Gel-200 group. In the immunogenicity assay, hylan G-F 20 induced a positive PCA reaction, but the Gel-200 did not.ConclusionGel-200 showed more favorable biocompatibility and less immunogenicity compared to hylan G-F 20. Gel-200 is expected to be a single injection hyaluronan product with less safety concerns for the treatment of knee osteoarthritis (OA) pain

A Chain Oriented Data Collection Protocol for Energy-Aware and Delay-Constrained WSN

Energy awareness plays an important role in developing routing protocol for the battery powered wireless sensor networks. As the replacement of the battery is often unfeasible in practical situations, we present here an optimal solution for the maximum utilization of precious available energy at the same time trying to minimize the latency in data delivery. We propose to form hierarchical chains with deployed sensors to collect information from a target field where data get fused at every node level before transmitted finally. Our protocol utilizes the higher energy nodes for more frequent long distance transmissions so that the energy expenditure become even between all nodes in the network irrespective of their physical locations. It has been found in our simulation that this protocol outperforms other hierarchical protocols like LEACH and PEGASIS in both the cases of energy consumption and time requirements respectively. It has been also found that the overall lifetime of the sensor network also increases in our protocol

The role of ECL2 in CGRP receptor activation: a combined modelling and experimental approach

The calcitonin gene-related peptide (CGRP) receptor is a complex of a calcitonin receptor-like receptor (CLR), which is a family B G-protein-coupled receptor (GPCR) and receptor activity modifying protein 1. The role of the second extracellular loop (ECL2) of CLR in binding CGRP and coupling to Gs was investigated using a combination of mutagenesis and modelling. An alanine scan of residues 271–294 of CLR showed that the ability of CGRP to produce cAMP was impaired by point mutations at 13 residues; most of these also impaired the response to adrenomedullin (AM). These data were used to select probable ECL2-modelled conformations that are involved in agonist binding, allowing the identification of the likely contacts between the peptide and receptor. The implications of the most likely structures for receptor activation are discussed.</jats:p