The evolving world of pseudoenzymes: proteins, prejudice and zombies

Pseudoenzymes are catalytically deficient variants of enzymes that are represented in all major enzyme families. Their regulatory functions in signalling pathways are shedding new light on the non-catalytic functions of active enzymes, and are suggesting new ways to target cellular signalling mechanisms with drugs

SDSS J142625.71+575218.3: A Prototype for A New Class of Variable White Dwarf

We present the results of a search for pulsations in six of the recently discovered carbon-atmosphere white dwarf ("hot DQ") stars. On the basis of our theoretical calculations, the star SDSS J142625.71 + 575218.3 is the only object expected to pulsate. We observe this star to be variable, with significant power at 417.7 s and 208.8 s ( first harmonic), making it a strong candidate as the first member of a new class of pulsating white dwarf stars, the DQVs. Its folded pulse shape, however, is quite different from that of other white dwarf variables and shows similarities with that of the cataclysmic variable AM CVn, raising the possibility that this star may be a carbon-transferring analog of AM CVn stars. In either case, these observations represent the discovery of a new and exciting class of object.NSF AST-0507639, AST-0602288, AST-0607480, AST-0307321Astronom

Global MHD simulation of flux transfer events at the high-latitude magnetopause observed by the cluster spacecraft and the SuperDARN radar system

A global magnetohydrodynamic numerical simulation is used to study the large-scale structure and formation location of flux transfer events (FTEs) in synergy with in situ spacecraft and ground-based observations. During the main period of interest on the 14 February 2001 from 0930 to 1100 UT the Cluster spacecraft were approaching the Northern Hemisphere high-latitude magnetopause in the postnoon sector on an outbound trajectory. Throughout this period the magnetic field, electron, and ion sensors on board Cluster observed characteristic signatures of FTEs. A few minutes delayed to these observations the Super Dual Auroral Radar Network (SuperDARN) system indicated flow disturbances in the conjugate ionospheres. These “two-point” observations on the ground and in space were closely correlated and were caused by ongoing unsteady reconnection in the vicinity of the spacecraft. The three-dimensional structures and dynamics of the observed FTEs and the associated reconnection sites are studied by using the Block-Adaptive-Tree-Solarwind-Roe-Upwind-Scheme (BATS-R-US) MHD code in combination with a simple open flux tube motion model (Cooling). Using these two models the spatial and temporal evolution of the FTEs is estimated. The models fill the gaps left by measurements and allow a “point-to-point” mapping between the instruments in order to investigate the global structure of the phenomenon. The modeled results presented are in good correlation with previous theoretical and observational studies addressing individual features of FTEs

Mechanically-stacked tandem solar cells with GaAsP on GaP and silicon

Preliminary results are encouraging for the achievement of high conversion efficiencies using a GaAsP top solar cell mechanically stacked on a conventional silicon solar cell. A realistic maximum of 29.4 percent is suggested when both the top and bottom solar cells are state of the art. Practical system efficiencies greater than 25 percent are attainable in the near future with the use of a state of the art bottom solar cell

Platelet polyphosphate induces fibroblast chemotaxis and myofibroblast differentiation

BackgroundPlatelets secrete many pro‐wound healing molecules such as growth factors and cytokines. We found that releasates from activated human platelets induced the differentiation of cultured murine and human fibroblasts into a myofibroblast phenotype. Surprisingly, most of this differentiation‐inducing activity was heat‐stable, suggesting it was not due to the protein component of the releasates. Inorganic polyphosphate is a major constituent of platelet‐dense granules and promotes blood coagulation and inflammation.ObjectivesWe aim to investigate the contribution of polyphosphate on myofibroblast differentiating activity of platelet releasates.MethodsUsing NIH‐3T3 cells and primary human fibroblasts, we examined the effect of human platelet releasates and chemically synthesized polyphosphate on fibroblast differentiation and migration.ResultsWe found that the myofibroblast‐inducing activity of platelet releasates was severely attenuated after incubation with a polyphosphate‐degrading enzyme, and that fibroblasts responded to platelet‐sized polyphosphate by increased levels of α‐smooth muscle actin, stress fibers, and collagen. Furthermore, fibroblasts were chemotactic toward polyphosphate.ConclusionsThese findings indicate that platelet‐derived polyphosphate acts as a cell signaling molecule by inducing murine and human fibroblasts to differentiate into myofibroblasts, a cell type known to drive both wound healing and fibrosing diseases. Polyphosphate therefore not only promotes early wound responses through enhancing fibrin clot formation, but also may play roles in the later stages of wound healing, and, potentially, progression of fibrotic diseases, by recruiting fibroblasts and inducing their differentiation into myofibroblasts.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163376/2/jth15066_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163376/1/jth15066.pd

Implementation and performance of SIBYLS: a dual endstation small-angle X-ray scattering and macromolecular crystallography beamline at the Advanced Light Source.

The SIBYLS beamline (12.3.1) of the Advanced Light Source at Lawrence Berkeley National Laboratory, supported by the US Department of Energy and the National Institutes of Health, is optimized for both small-angle X-ray scattering (SAXS) and macromolecular crystallography (MX), making it unique among the world's mostly SAXS or MX dedicated beamlines. Since SIBYLS was commissioned, assessments of the limitations and advantages of a combined SAXS and MX beamline have suggested new strategies for integration and optimal data collection methods and have led to additional hardware and software enhancements. Features described include a dual mode monochromator [containing both Si(111) crystals and Mo/B(4)C multilayer elements], rapid beamline optics conversion between SAXS and MX modes, active beam stabilization, sample-loading robotics, and mail-in and remote data collection. These features allow users to gain valuable insights from both dynamic solution scattering and high-resolution atomic diffraction experiments performed at a single synchrotron beamline. Key practical issues considered for data collection and analysis include radiation damage, structural ensembles, alternative conformers and flexibility. SIBYLS develops and applies efficient combined MX and SAXS methods that deliver high-impact results by providing robust cost-effective routes to connect structures to biology and by performing experiments that aid beamline designs for next generation light sources

Estimation of relative abundance of recreationally important finfish in the Virginia portion of the Chesapeake Bay : annual progress report, U.S. Fish and Wildlife Service Sportfish Restoration Project F104R2, July 1992 - June 1993, Revised edition 1994

This document is a revised edition of an original manuscript presented to the U.S. Fish and Wildlife Service and the Virginia Marine Resources Commission in partial fulfillment of contract obligations (Sportfish Restoration Project F104R2)