Rapid reversion from monomer to dimer regenerates the ultraviolet-B photoreceptor UV RESISTANCE LOCUS8 in intact arabidopsis plants

Arabidopsis (Arabidopsis thaliana) UV RESISTANCE LOCUS8 (UVR8) is a photoreceptor that specifically mediates photomorphogenic responses to ultraviolet (UV)-B in plants. UV-B photoreception induces the conversion of the UVR8 dimer into a monomer that interacts with the CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) protein to regulate gene expression. However, it is not known how the dimeric photoreceptor is regenerated in plants. Here, we show, by using inhibitors of protein synthesis and degradation via the proteasome, that the UVR8 dimer is not regenerated by rapid de novo synthesis following destruction of the monomer. Rather, regeneration occurs by reversion from the monomer to the dimer. However, regeneration of dimeric UVR8 in darkness following UV-B exposure occurs much more rapidly in vivo than in vitro with illuminated plant extracts or purified UVR8, indicating that rapid regeneration requires intact cells. Rapid dimer regeneration in vivo requires protein synthesis, the presence of a carboxyl-terminal 27-amino acid region of UVR8, and the presence of COP1, which is known to interact with the carboxyl-terminal region. However, none of these factors can account fully for the difference in regeneration kinetics in vivo and in vitro, indicating that additional proteins or processes are involved in UVR8 dimer regeneration in vivo

Telerobot for space station

The Flight Telerobotic Servicer (FTS), a multiple arm dexterous manipulation system, will aid in the assembly, maintenance, and servicing of the space station. Fundamental ideas and basic conceptual designs for a shuttle-based telerobot system have been produced. Recent space station studies provide additional concepts that should aid in the accomplishment of mission requirements. Currently, the FTS is in contractual source selection for a Phase B preliminary design. At the same time, design requirements are being developed through a series of robotic assessment tasks being performed at NASA and commercial installations. A number of the requirements for remote operation on the space station, necessary to supplement extravehicular activity (EVA), will be met by the FTS. Finally, technology developed for telerobotics will advance the state of the art of remote operating systems, enhance operator productivity, and prove instrumental in the evolution of an adaptive, intelligent autonomous robot

A comparison of experimental and calculated thin-shell leading-edge buckling due to thermal stresses

High-temperature thin-shell leading-edge buckling test data are analyzed using NASA structural analysis (NASTRAN) as a finite element tool for predicting thermal buckling characteristics. Buckling points are predicted for several combinations of edge boundary conditions. The problem of relating the appropriate plate area to the edge stress distribution and the stress gradient is addressed in terms of analysis assumptions. Local plasticity was found to occur on the specimen analyzed, and this tended to simplify the basic problem since it effectively equalized the stress gradient from loaded edge to loaded edge. The initial loading was found to be difficult to select for the buckling analysis because of the transient nature of thermal stress. Multiple initial model loadings are likely required for complicated thermal stress time histories before a pertinent finite element buckling analysis can be achieved. The basic mode shapes determined from experimentation were correctly identified from computation

Results of the 2010/2011 Hospice Patient Survey General Report

The 2010/11 survey is the fourth in a series of surveys on patient satisfaction with inpatient and daycare services. Carried out by Help the Hospices and the Centre for Health Services Studies at the University of Kent, with previous surveys being completed in 2004/05, 2006/07 and 2008/09. All hospices across the UK were invited to take part in the 2010/11 Patient Survey and 39 hospices participated between September 2010 and May 2011

A new deformation mechanism in pyrolytic carbon at high temperatures

Creep deformation mechanism of pyrolytic graphite at high temperatures in response to stres