A fish perspective: detecting flow features while moving using an artificial lateral line in steady and unsteady flow

For underwater vehicles to successfully detect and navigate turbulent flows, sensing the fluid interactions that occur is required. Fish possess a unique sensory organ called the lateral line. Sensory units called neuromasts are distributed over their body, and provide fish with flow-related information. In this study, a three-dimensional fish-shaped head, instrumented with pressure sensors, was used to investigate the pressure signals for relevant hydrodynamic stimuli to an artificial lateral line system. Unsteady wakes were sensed with the objective to detect the edges of the hydrodynamic trail and then explore and characterize the periodicity of the vorticity. The investigated wakes (Kármán vortex streets) were formed behind a range of cylinder diameter sizes (2.5, 4.5 and 10 cm) and flow velocities (9.9, 19.6 and 26.1 cm s⁻¹). Results highlight that moving in the flow is advantageous to characterize the flow environment when compared with static analysis. The pressure difference from foremost to side sensors in the frontal plane provides us a useful measure of transition from steady to unsteady flow. The vortex shedding frequency (VSF) and its magnitude can be used to differentiate the source size and flow speed. Moreover, the distribution of the sensing array vertically as well as the laterally allows the Kármán vortex paired vortices to be detected in the pressure signal as twice the VSF.     

A PCR-based non-radioactive X-chromosome inactivation assay for genetic counseling in X-linked primary immunodeficiencies

The Wiskott-Aldrich syndrome (WAS), X-linked severe combined immunodeficiency (SCIDX1), and X-linked agammaglobulinemia (XLA) are severe congenital immunodeficiencies with X-linked inheritance. Although rare, they are all associated with severe infections from early in life, and high morbidity and mortality. Female carriers of these diseases can be identified by a non-random pattern of X-chromosomal inactivation in cell lineages targeted by each gene defect. For patients with WAS, SCIDX1 or XLA, the demonstration of non random X-Chromosome inactivation in their mothers can be used to confirm clinical diagnosis. Furthermore, analysis of X-Chromosome inactivation in at risk females allows preconceptional carrier detection, thus representing an important aid in genetic counseling. For each disease we established a PCR-based, non radioactive assay at the human androgen receptor (HUMARA) locus, that allows analysis of X-Chromosome inactivation in the affected cell types and in tissue specific controls to exclude the issue of skewed X-chromosomal inactivation. In our study, 50 females with a known family history of XLA [19], WAS [18], and SCIDX1 [13],were examined. A carrier status was established in 19 females (7 XLA, 6 WAS, 6 SCIDX1) and excluded in 29 ( 11 XLA, 11 WAS, 7 SCIDX1). Only in 2 cases (4%) the assay was not informative.     

Male mouse (Mus musculus) attraction to airborne urinary odors of conspecifics and to food odors: Effects of food deprivation.

Five experiments demonstrated that 112 male mice were strongly attracted to the urinary odors of females, and that male urinary odors were considerably less attractive. The strong attraction to female urinary odors did not require that the males have postweaning experience with females. Males with continuous access to food and water were much more strongly attracted to female urinary odors than to the airborne food odors. Female urinary odors remained more attractive than food odors after 24-hr food deprivation, and only after 48-hr deprivation did the attractiveness of food odors approximate that of female urine. Although 48-hr food deprivation appeared to equalize the attractiveness of urinary and food odors, this regimen did so not by diminishing the attractiveness of female urine but rather by increasing the attractiveness of food odors. It is argued that the attraction that male mice exhibited to female urinary odors in this odor-testing apparatus reflected, at least in part, a biologically important precopulatory communication system. (29 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Probability of inelastic nuclear interactions of high-energy protons in a bent crystal

Probability of inelastic nuclear interactions in a short bent silicon crystal for its orientations optimal for channeling and volume reflection was investigated using 400 GeV/c protons of the CERN SPS. The contribution of nuclear interactions from channeled protons was observed to be about 3–4% of the probability for the amorphous orientation. For the crystal orientation optimal for volume reflection the nuclear interaction probability of protons was a few percents larger than in the amorphous case. It was shown that in the limiting case of a quasi parallel beam realizing for the collider beam halo the inelastic nuclear losses should decrease by more than five times, which is an additional advantage of a crystal as a primary collimator for the LHC collimation system.     

A concerted study using binding measurements, X-ray structural data, and molecular modeling on the stereochemical features responsible for the affinity of 6-arylpyrrolo[2,1-d][1,5]benzothiazepines toward mitochondrial benzodiazepine receptors

The 7-(acyloxy)-6-arylpyrrolo[2,1-d][1,5]benzothiazepine derivatives have been recently proposed as a new class of ligands specific for the mitochondrial benzodiazepine receptor (Fiorini et al. J. Med. Chem. 1994, 37, 1427-1438) (Greco et al. J. Med. Chem. 1994, 37, 4100-4108). In this paper we report the X-ray crystallographic structures of three potent (1-3) and two inactive (4 and 5) previously described benzothiazepines, as well as binding affinity constants for two newly assayed analogs in which the acyloxy side chain was replaced by a methoxy group (6) or removed (7). Structure-affinity relationships and molecular mechanics calculations performed using crystal structures as references have led to a revised 3D pharmacophore model accounting for all the data available up until now. Interestingly, the hypothetical receptor-bound conformations of 1-3 display a considerable degree of similarity with their crystal geometries. Additional calculations have confirmed that the poor affinities of benzothiazepines bearing an aroyloxy group (4 and 5) should be ascribed to the steric and/or electronic features of the side chain aryl moieties rather than to unfavorable conformational properties.     

Chemical Modification of Bisphenol A Polycarbonate by Reactive Blending with Cyclic Anhydrides

Summary Reactive blending with cyclic anhydrides in the melt is a promising process to modify the chemical structure of bisphenol A polycarbonate (PC) by insertion of ester moieties leading to consistent changes in the chemical and physical properties of PC. In particular, by the reaction with succinic anhydride it is possible to insert aliphatic moieties in the polymer backbone, decreasing the melt viscosity and the glass transition temperature of PC (and thus increase its processability). The reaction, that is catalysed by Lewis acids (e. g. titanium butoxide), proceeds through the formation of carbonyl carbonate groups that undergo decarboxylation leading to ester moieties. No side reactions have been detected by NMR analysis. The addition of phosphorous acid as catalyst quencher at the end of the process gives rise to polymers with good colour and thermal stability.