A Drosophila homolog of bovine smg p25a GDP dissociation inhibitor undergoes a shift in isoelectric point in the developmental mutant quartet

The Drosophila developmental mutation quartet causes late larval lethality and small imaginal discs and, when expressed in the adult female, has a lethal effect on early embryogenesis. These developmental defects are associated with mitotic defects, which include a low mitotic index in larval brains and incomplete separation of chromosomes in mitosis in the early embryo. quartet mutations also have a biochemical effect, i.e., a basic shift in isoelectric point in three proteins. We have purified one of these proteins, raised an antibody to it, and isolated and sequenced its cDNA. At the amino acid level, the sequence shows 68% identity and 81% similarity to bovine smg p25a GDP dissociation inhibitor (GDI), a regulator of ras-like small GTPases of the rab/SEC4/YPT1 subfamily. The correlation between a basic shift in isoelectric point in Drosophila GDI in quartet mutant tissue and the quartet developmental phenotype raises the possibility that a posttranslational modification of GDI is necessary for its function and that GDI function is essential for development.     

Melt processing and characterization of polyvinyl alcohol and polyhydroxyalkanoate multilayer films

Multilayer films for food packaging applications composed of polyvinyl alcohol (PVOH) as the core layer and polyhydroxyalkanoate (PHA) as the outer skin layers were produced by the co‐extrusion process. Rheological properties of PVOH and PHA were performed and analyzed before co‐extruding into a cast film. Analysis of the rheological data indicated the processing temperatures and grades of the PVOH and PHA polymers that would produce similar viscosity and melt flow properties. To improve adhesion of the layers, PHA was grafted with maleic anhydride using a dicumyl peroxide initiator to provide a tie layer material, which improved the peel strength of the PHA and PVOH layers by over 2×. Oxygen transmission rate (OTR) testing showed that the multilayer sample provided an OTR of 27 cc/m²‐day at 0% relative humidity (RH) and rates of 41 and 52 cc/m²‐day at relative humidity values of 60% and 90% RH, respectively. This indicates significant barrier performance enhancement over monolayer PVOH that provided an OTR of 60 cc/m²‐day at 0% RH and 999 cc/m²‐day at 60% RH. Biodegradation testing of the films in the marine environment showed that both the unmodified and maleated PHA polymers displayed high levels of mineralization, whereas the PVOH material did not. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effects of individual characteristics,organizational factors and task characteristics on computer programmer productivity and job satisfaction

Several individual characteristics of computer programmers (self- esteem, level of experience, and mathematical aptitude); four organizational factors (perceived supervisory initiated structure, perceived supervisor consideration, perceived level of performance feedback, and perceived degree of participation in organizational decisions); and five task characteristics (skill variety, task variety, task significance, autonomy, and feedback) are related to computer programmer productivity and job satisfaction. Measurement was accomplished via questionnaires; least squares multiple regression was used to test the hypotheses.     

NOSER: An algorithm for solving the inverse conductivity problem

The inverse conductivity problem is the mathematical problem that must be solved in order for electrical impedance tomography systems to be able to make images. Here we show how this inverse conductivity problem is related to a number of other inverse problem. We then explain the workings of an algorithm that we have used to make images from electrical impedance data measured on the boundary of a circle in two dimensions. This algorithm is based on the method of least squares. It takes one step of a Newton's method, using a constant conductivity as an initial guess. Most of the calculations can therefore be done analytically. The resulting code is named NOSER, for Newton's One-Step Error Reconstructor. It provides a reconstruction with 496 degrees of freedom. The code does not reproduce the conductivity accurately (unless it differs very little from a constant), but it yields useful images. This is illustrated by images reconstructed from numerical and experimental data, including data from a human chest.     

Conceptual semantics in a nonhuman primate.

Some animal vocalizations have been described as referential, or semantic, because individuals respond to them as if they designate some object or event. Alternatively, subjects may simply attend to the acoustic features of calls rather than their meanings. Field playback experiments on diana monkeys (Cercopithecus diana diana) tested these hypotheses using the calls of leopards and eagles and the males' alarm calls to these predators. In the experiment, 2 calls were played in sequence, separated by 5 min of silence, such that they were either (a) similar in acoustic and semantic features, (b) similar in semantic features only, or (c) different in both acoustic and semantic features. Subjects readily transferred habituation across acoustic but not semantic features, suggesting that they attended to the calls' underlying meanings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A wrinkle in flight: the role of elastin fibres in the mechanical behaviour of bat wing membranes

Bats fly using a thin wing membrane composed of compliant, anisotropic skin. Wing membrane skin deforms dramatically as bats fly, and its three-dimensional configurations depend, in large part, on the mechanical behaviour of the tissue. Large, macroscopic elastin fibres are an unusual mechanical element found in the skin of bat wings. We characterize the fibre orientation and demonstrate that elastin fibres are responsible for the distinctive wrinkles in the surrounding membrane matrix. Uniaxial mechanical testing of the wing membrane, both parallel and perpendicular to elastin fibres, is used to distinguish the contribution of elastin and the surrounding matrix to the overall membrane mechanical behaviour. We find that the matrix is isotropic within the plane of the membrane and responsible for bearing load at high stress; elastin fibres are responsible for membrane anisotropy and only contribute substantially to load bearing at very low stress. The architecture of elastin fibres provides the extreme extensibility and self-folding/self-packing of the wing membrane skin. We relate these findings to flight with membrane wings and discuss the aeromechanical significance of elastin fibre pre-stress, membrane excess length, and how these parameters may aid bats in resisting gusts and preventing membrane flutter.     

Retention in an aftercare program for recovering women

Examining the correlates of aftercare participation is critical to program development and successful relapse prevention. This study assesses retention in an aftercare program of case management and peer support for formerly homeless recovering mothers. Length of residential drug treatment, length of sobriety, strong support networks, and concerns about housing and parenting predicted completion of the case management component. Emotional instability and the severity of problems were found to be correlated with participation in the peer support group. Sociodemographic characteristics were not related to program retention. The findings illustrate the need to tailor aftercare services to the level of clients' recovery and the need for female-only aftercare groups where women can safely discuss physical and sexual abuse issues related to their misuse of drugs.     

Utility of multivariate analysis in modeling the effects of raw material properties and operating parameters on granule and ribbon properties prepared in roller compaction

This article aimed to model the effects of raw material properties and roller compactor operating parameters (OPs) on the properties of roller compacted ribbons and granules with the aid of principal component analysis (PCA) and partial least squares (PLS) projection. A database of raw material properties was established through extensive physical and mechanical characterization of several microcrystalline cellulose (MCC) and lactose grades and their blends. A design of experiment (DoE) was used for ribbon production. PLS models constructed with only OP-modeled roller compaction (RC) responded poorly. Inclusion of raw material properties markedly improved the goodness of fit (R(2) = .897) and model predictability (Q(2) = 0.72).