A microangiographic study of the effect of hyperthermia on the rabbit bladder

A model was used to study the effect of hyperthermia on a normal tissue. The model selected was the rabbit bladder and the end point measured was the changes in the micro-vasculature of the bladder wall. It was already demonstrated clinically that hot water bladder infusions produce regression in bladder tumors

Dust Explosions and Collapsed Ductwork

PresentationOne of the more obvious consequences of a dust deflagration inside process equipment or a structure is the mechanical damage caused by shock (compression) waves. This overpressure damage is revealed through the displacement of equipment, the outward deformation or rupture of enclosures constructed of ductile materials, or the projection of missiles. However, a different type of damage is sometimes observed in the ductwork connecting process equipment. In particular, the ductwork is collapsed as if it were subjected to an external, rather than an internal pressure. The phenomenon that causes this collapse of thin-walled conduit is a gas dynamic process called an expansion wave. When a dust deflagration travels through a conduit, it accelerates and causing a rise in pressure. When the dust deflagration is vented (say through a deflagration vent), the discharge of the high pressure combustion products causes the formation of an expansion wave that travels in the reverse direction from the vent backwards. The expansion wave causes the pressure in the ductwork to fall below atmospheric pressure. The sub-atmospheric pressure, in turn, causes the ductwork to fail by buckling. In this study, we examine the gas dynamics of the expansion wave, demonstrate how to calculate the degree of pressure drop caused by the expansion wave, and illustrate the concept with case studies of dust explosions

Supermagnetosonic jets behind a collisionless quasi-parallel shock

The downstream region of a collisionless quasi-parallel shock is structured containing bulk flows with high kinetic energy density from a previously unidentified source. We present Cluster multi-spacecraft measurements of this type of supermagnetosonic jet as well as of a weak secondary shock front within the sheath, that allow us to propose the following generation mechanism for the jets: The local curvature variations inherent to quasi-parallel shocks can create fast, deflected jets accompanied by density variations in the downstream region. If the speed of the jet is super(magneto)sonic in the reference frame of the obstacle, a second shock front forms in the sheath closer to the obstacle. Our results can be applied to collisionless quasi-parallel shocks in many plasma environments.Comment: accepted to Phys. Rev. Lett. (Nov 5, 2009

Vitellogenin and vitellogenin-like gene expression patterns in relation to caste and task in the ant Formica fusca

Social insect colonies are characterized by division of labour, and extensive morphological, physiological and behavioural differences between queens and workers. The storage protein vitellogenin (Vg) affects multiple aspects of social insect life histories, and has been suggested as a key player for caste differentiation and maintenance. Recently, three genes homologous to Vg have been described in the ant Formica exsecta. Their role is currently unclear but their structural variation suggests variable functions. We examined the expression patterns of the conventional Vg and the three Vg-like genes using qRT-PCR in the common black ant Formica fusca between queens and workers, between nurse and foragers workers, and across social contexts (queenless vs. queenright nests), and sampling time. As expected, we found a significant queen caste and nurse task-related increase for the conventional Vg, while Vg-like-C displayed a consistent forager-biased expression pattern. Task (forager vs. nurse) was the only factor that explained expression variation among workers in any of the studied genes. The removal of the queen did not affect expression, although the proportion of fertile nurses increased in queenless nests. The observed expression biases suggest that in Formica fusca, the ancestral duplication has led to alternative social functions for Vg-like genes across castes and tasks. To get a broader picture of the role of gene duplications in social evolution and the roles of Vg-like genes in caste differentiation and maintenance, how these genes achieve these roles at a molecular level need to be investigated further.Peer reviewe

Highly selective recovery of Ni(II) in neutral and acidic media using a novel Ni(II)-ion imprinted polymer

In this work, an original ion-imprinted polymer (IIP) was synthetized for the highly selective removal of Ni(II) ions in neutral and acidic media. First a novel functional monomer (AMP-MMA) was synthetized through the amidation of 2-(aminomethyl)pyridine (AMP) with methacryloylchloride. Following Ni(II)/AMP-MMA complex formation study, the Ni(II)-IIP was produced via inverse suspension polymerization (DMSO in mineral oil) and characterized with solid state 13C CPMAS NMR, FT-IR, SEM and nitrogen adsorption/desorption experiments. The Ni(II)-IIP was then used in solid-phase extraction of Ni(II) exploring a wide range of pH (from neutral to strongly acidic solution), several initial concentrations of Ni(II) (from 0.02 to 1 g/L), and the presence of competitive ions (Co(II), Cu(II), Cd(II), Mn(II), and Mg(II)). The maximum Ni(II) adsorption capacity at pH 2 and pH 7 reached values of 138.9 mg/g and 169.5 mg/g, that are among the best reported in literature. The selectivity coefficients toward Cd(II), Mn(II), Co(II), Mg(II) and Cu(II) are also very high, with values up to 38.6, 32.9, 25.2, 23.1 and 15.0, respectively. The Ni(II)-IIP showed good reusability of up to 5 cycles both with acidic and basic Ni(II) eluents.Peer reviewe

Self-consistent modeling of the energetic storm particle event of November 10, 2012

It is thought that solar energetic ions associated with coronal/interplanetary shock waves are accelerated to high energies by the diffusive shock acceleration mechanism. For this mechanism to be efficient, intense magnetic turbulence is needed in the vicinity of the shock. The enhanced turbulence upstream of the shock can be produced self-consistently by the accelerated particles themselves via streaming instability. Comparisons of quasi-linear-theory-based particle acceleration models that include this process with observations have not been fully successful so far, which has motivated the development of acceleration models of a different nature. The aim of this work is to test how well our self-consistent quasi-linear SOLar Particle Acceleration in Coronal Shocks (SOLPACS) simulation code, developed earlier to simulate proton acceleration in coronal shocks, models the particle foreshock region. We applied SOLPACS to model the energetic storm particle (ESP) event observed by the STEREO A spacecraft on November 10, 2012. In the simulations, all but one main input parameter of SOLPACS are fixed by the in-situ plasma measurements from the spacecraft. By comparing a simulated proton energy spectrum at the shock with the observed one, we were able to fix the last simulation input parameter related to the efficiency of particle injection to the acceleration process. A subsequent comparison of simulated proton time-intensity profiles in a number of energy channels with the observed ones shows a very good correspondence throughout the upstream region

Observations Of Hall Reconnection Physics Far Downstream Of The X Line

Observations made using the Wind spacecraft of Hall magnetic fields in solar wind reconnection exhausts are presented. These observations are consistent with the generation of Hall fields by a narrow ion inertial scale current layer near the separatrix, which is confirmed with an appropriately scaled particle-in-cell simulation that shows excellent agreement with observations. The Hall fields are observed thousands of ion inertial lengths downstream from the reconnection X line, indicating that narrow regions of kinetic dynamics can persist extremely far downstream