Off-duty activity equipment and facilities for advanced spacecraft /preliminary design/

Off-duty activity equipment and facilities preliminary design for advanced spacecraf

Stabilization and precise calibration of a continuous-wave difference frequency spectrometer by use of a simple transfer cavity

A novel, simple, and inexpensive calibration scheme for a continuous-wave difference frequency spectrometer is presented, based on the stabilization of an open transfer cavity by locking onto the output of a polarization stabilized HeNe laser. High frequency, acoustic fluctuations of the transfer cavity length are compensated with a piezoelectric transducer mounted mirror, while long term drift in cavity length is controlled by thermal feedback. A single mode Ar+ laser, used with a single mode ring dye laser in the difference frequency generation of 2–4 µm light, is then locked onto a suitable fringe of this stable cavity, achieving a very small long term drift and furthermore reducing the free running Ar+ linewidth to about 1 MHz. The dye laser scan provides tunability in the difference frequency mixing process, and is calibrated by marker fringes with the same stable cavity. Due to the absolute stability of the marker cavity, precise frequency determination of near infrared molecular transitions is achieved via interpolation between these marker fringes. It is shown theoretically that the residual error of this scheme due to the dispersion of air in the transfer cavity is quite small, and experimentally that a frequency precision on the order of 1 MHz per hour is routinely obtained with respect to molecular transitions. Review of Scientific Instruments is copyrighted by The American Institute of Physics

DWNN, a novel ubiquitin-like domain, implicates RBBP6 in mRNA processing and ubiquitin-like pathways

BACKGROUND: RBBP6 is a 250 kDa splicing-associated protein that has been identified as an E3 ligase due to the presence of a RING finger domain. In humans and mice it interacts with both p53 and Rb, and plays a role in the induction of apoptosis and regulation of the cell cycle. RBBP6 has recently been shown to be highly up-regulated in oesophageal cancer, and to be a promising target for immunotherapy against the disease. RESULTS: We show here using heteronuclear NMR that the N-terminal 81 amino acids of RBBP6 constitute a novel ubiquitin-like domain, which we have called the DWNN domain. The domain lacks conserved equivalents of K(48 )and K(63), although the equivalents of K(6 )and K(29 )are highly, although not absolutely, conserved. The di-glycine motif that is characteristic of proteins involved in ubiquitination is found in the human and mouse form of the domain, although it is not present in all organisms. It forms part of a three-domain form of RBBP6 containing the DWNN domain, a zinc knuckle and a RING finger domain, which is found in all eukaryotic genomes so far examined, in the majority of cases at single copy number. The domain is also independently expressed in vertebrates as a single domain protein. CONCLUSION: DWNN is a novel ubiquitin-like domain found only at the N-terminus of the RBBP6 family of splicing-associated proteins. The ubiquitin-like structure of the domain greatly increases the likelihood that RBBP6 functions through some form of ubiquitin-like modification. Furthermore, the fact that the DWNN domain is independently expressed in higher vertebrates leads us to propose that the domain may itself function as a novel ubiquitin-like modifier of other proteins

Qualitative description of factors involved in the retraction and lysis of dilute whole blood clots and in aggregation and retraction of platelets

AB S T R A C T Dilute whole blood clots were prepared by addition of thrombin to blood diluted 1: 10 in phosphate buffer. The pH of this buffer was 7.4 and the ionic strength was 0.084. Though the ionic strength was low, there was no hemolysis of red corpuscles due to the contribution to the osmotic gradient by plasma salts and proteins. In the standard assay the clot was formed by addition of thrombin at 4VC then incubated at 370C. Retraction and lysis of these clots were inhibited by removal of platelets and by increasing concentrations of purified thrombin. Retraction and lysis were also inhibited by inactivation of any one of the following factors: YM globulin, complement components C4 and 3, and (in the case of lysis) plasminogen. Evidence that some of the above serum factors were adsorbed to the platelet membrane was obtained by aggregation of washed platelets by antisera to these factors (i.e. fibrinogen, 'yM, and C4 or C3). These platelets were not aggregated by antisera to other serum proteins (by albumin, transferrin, yG globulin). These and other studies suggested that platelets, thrombin, fibrinogen, yM globulin (cold agglutinin), complement components, and plasminogen influenced and facilitated retraction and lysis of clots. These studies also suggested that platelets and some of these factors were physically associated. Because of this physical association, and because of the fact that clot retraction is associated with aggregation and retraction of platelets, we extended the above observations to include a study of the effect of these same serum factors on serum-induced aggregation and retraction of washed platelets. (Other terms which have been in use in the past to describe serum-induced platelet aggregation and retraction have included those such as Received for publication 29 December 1969 and in revised form 22 June 1970. platelet "fusion" and "viscous metamorphosis," neither of which fully described the phenomena.) Platelet aggregation and retraction induced by serum was markedly accelerated by addition of increasing concentrations of thrombin and (or) cold agglutinin. Hirudin and antisera to yM globulin inhibited seruminduced aggregation and retraction of platelets. Reconstitution of inactivated serum with purified C4, 3, and 5 and thrombin restored its capacity to induce aggregation and retraction of platelets. Therefore, we postulated that platelet aggregation and retraction were necessary for clot retraction and that platelet aggregation and clot retraction facilitated clot lysis. More specifically we postulated that thrombin, in addition to catalyzing clot formation, also modified the platelet membrane such that yM globulin (cold agglutinin) and complement components can act on the platelet membrane leading to (a) aggregation and retraction of the platelets, (b) retraction of the clot, and (c) to the activation of plasminogen either on the surface of the platelet by C8i and (or) by release of platelet activators of plasminogen

Limits on Production of Magnetic Monopoles Utilizing Samples from the DO and CDF Detectors at the Tevatron

We present 90% confidence level limits on magnetic monopole production at the Fermilab Tevatron from three sets of samples obtained from the D0 and CDF detectors each exposed to a proton-antiproton luminosity of $\sim175 {pb}^{-1}$ (experiment E-882). Limits are obtained for the production cross-sections and masses for low-mass accelerator-produced pointlike Dirac monopoles trapped and bound in material surrounding the D0 and CDF collision regions. In the absence of a complete quantum field theory of magnetic charge, we estimate these limits on the basis of a Drell-Yan model. These results (for magnetic charge values of 1, 2, 3, and 6 times the minimum Dirac charge) extend and improve previously published bounds.Comment: 18 pages, 17 figures, REVTeX

PGC-1alpha dictates endothelial function through regulation of eNOS expression

Endothelial dysfunction is a characteristic of many vascular related diseases such as hypertension. Peroxisome proliferator activated receptor gamma, coactivator 1alpha (PGC-1alpha) is a unique stress sensor that largely acts to promote adaptive responses. Therefore, we sought to define the role of endothelial PGC-1alpha in vascular function using mice with endothelial specific loss of function (PGC-1alpha EC KO) and endothelial specific gain of function (PGC-1alpha EC TG). Here we report that endothelial PGC-1alpha is suppressed in angiotensin-II (ATII)-induced hypertension. Deletion of endothelial PGC-1alpha sensitized mice to endothelial dysfunction and hypertension in response to ATII, whereas PGC-1alpha EC TG mice were protected. Mechanistically, PGC-1alpha promotes eNOS expression and activity, which is necessary for protection from ATII-induced dysfunction as mice either treated with an eNOS inhibitor (LNAME) or lacking eNOS were no longer responsive to transgenic endothelial PGC-1alpha expression. Finally, we determined that the orphan nuclear receptor, estrogen related receptor alpha (ERRalpha) is required to coordinate the PGC-1alpha -induced eNOS expression. In conclusion, endothelial PGC-1alpha expression protects from vascular dysfunction by promoting NO* bioactivity through ERRalpha induced expression of eNOS

Female Genitalia Concealment Promotes Intimate Male Courtship in a Water Strider

Violent coercive mating initiation is typical for animals with sexual conflict over mating. In these species, the coevolutionary arms-race between female defenses against coercive mating and male counter-adaptations for increased mating success leads to coevolutionary chases of male and female traits that influence the mating. It has been controversial whether one of the sexes can evolve traits that allow them to “win” this arms race. Here, we use morphological analysis (traditional and scanning electron micrographs), laboratory experiments and comparative methods to show how females of a species characterized by typical coercive mating initiation appear to “win” a particular stage of the sexual conflict by evolving morphology to hide their genitalia from direct, forceful access by males. In an apparent response to the female morphological adaptation, males of this species added to their typically violent coercive mounting of the female new post-mounting, pre-copulatory courtship signals produced by tapping the water's surface with the mid-legs. These courtship signals are intimate in the sense that they are aimed at the female, on whom the male is already mounted. Females respond to the signals by exposing their hidden genitalia for copulatory intromission. Our results indicate that the apparent victory of coevolutionary arms race by one sex in terms of morphology may trigger evolution of a behavioral phenotype in the opposite sex

Colony Defense Behavior of the Primitively Eusocial Wasp, Mischocyttarus cerberus is Related to Age

The colony defense behavior of the wasp Mischocyttarus cerberus Richards (Hymenoptera, Vespidae) was studied to verify whether there were different reactions of wasps of different ages and hierarchical positions during attacks of ants. Detailed nest mapping was first performed, then the wasps were marked and were divided in four distinct categories: queens, older workers, younger workers and males. Tests were made simulating attacks of ants in the nests. The main results showed that the M. cerberus behaviors against ant attacks is more related to the age of the wasps than to their hierarchical position. The oldest wasps (queens and older workers) defend the nest more than the younger workers and males, representing a form of temporal polyethism

Chiral dynamics of p-wave in K^- p and coupled states

We perform an evaluation of the p-wave amplitudes of meson-baryon scattering in the strangeness S=-1 sector starting from the lowest order chiral Lagrangians and introducing explicitly the Sigma^* field with couplings to the meson-baryon states obtained using SU(6) symmetry. The N/D method of unitarization is used, equivalent, in practice, to the use of the Bethe-Salpeter equation with a cut-off. The procedure leaves no freedom for the p-waves once the s-waves are fixed and thus one obtains genuine predictions for the p-wave scattering amplitudes, which are in good agreement with experimental results for differential cross sections, as well as for the width and partial decay widths of the Sigma^*(1385).Comment: LaTeX, 18 pages, 6 figure