Study of the anode plasma dynamics under the action of a high-power electron beam on epoxy resin

Results are presented from experimental studies of plasma dynamics in a diode gap under the action of a high-current relativistic electron beam on epoxy resin at energy densities in the range of 170–860 J/cm². The plasma expansion was studied by means of an optical streak camera. Three-dimensional numerical simulations in the one-temperature hydrodynamic approximation were also performed. The experimental data are compared with the results of numerical simulations.     

Determination of Fluorescence Polarization of Double Chromophore Complexes

Polarized fluorescence of rigid double-chromophore complexes with intracomplex energy exchange between chromophores was analyzed, and the formula for the degree of polarization derived for the case of steady-state excitation: P = (3 cos²θ - 1 + 2A)/(3 + cos²θ + 4A). In this formula θ is the angle between the transition dipole moments of chromophores in complexes, and A is the parameter dependent on the spectroscopic features of chromophores and energy migration rates. The case of excitation by a δ-pulse was also analyzed, and a formula for fluorescence polarization kinetics was derived.As an example of the application of the derived formulae, the polarized fluorescence spectra and their picosecond kinetics were calculated for the β-subunits of the blue-green algae Agmenellum quadruplicatum. The results obtained were compared with experimental measurements of Mimuro et al. (1986, Biochim. Biophys. Acta848, 155-166) and found to match these data well.     

Synthesis of trisaccharide fragment of O-specific polysaccharides of Salmonella of serologic groups C2 and C3 and its conversion into synthetic antigen of a copolymer type

Abequosyl-(alpha 1----3)-L-rhamnopyranosyl-(1----2)-D-mannopyranosides anomeric in the rhamnose residue have been synthesised. 2-Benzyloxycarbonylaminoethyl group used as the aglycon can be transformed into 2-acrylamidoethyl aglycon in the final stages of the syntheses. These isomeric alpha-glycosides were converted into copolymer artificial antigens, which are of interest for studying immunochemistry of factor O:8 of Salmonella O-antigens (serological groups C2 and C3).     

Maxim D. Frank-Kamenetskii: Diamond Jubilee of A Brilliant Scientist

Abstract Long-time friend, colleague and disciple of Maxim D. Frank-Kameneskii, Dr. Vadim V. Demidov, writes on Maxim on Maxim's 60th birthday. JBSD and Adenine Press join these congratulations and wish the jubilarian a happy birthday and many-many happy returns!     

Mice Deficient for the Wild-Type p53-Induced Phosphatase Gene (Wip1) Exhibit Defects in Reproductive Organs, Immune Function, and Cell Cycle Control

The Wip1 gene is a serine/threonine phosphatase that is induced in a p53-dependent manner by DNA-damaging agents. We show here that Wip1 message is expressed in moderate levels in all organs, but is present at very high levels in the testes, particularly in the postmeiotic round spermatid compartment of the seminiferous tubules. We have confirmed that Wip1 mRNA is induced by ionizing radiation in mouse tissues in a p53-dependent manner. To further determine the normal biological function of Wip1 in mammalian organisms, we have generated Wip1-deficient mice. Wip1 null mice are viable but show a variety of postnatal abnormalities, including variable male runting, male reproductive organ atrophy, reduced male fertility, and reduced male longevity. Mice lacking Wip1 show increased susceptibility to pathogens and diminished T- and B-cell function. Fibroblasts derived from Wip1 null embryos have decreased proliferation rates and appear to be compromised in entering mitosis. The data are consistent with an important role for Wip1 in spermatogenesis, lymphoid cell function, and cell cycle regulation.     

International guide to prescribing psychotropic medication for the management of problem behaviours in adults with intellectual disabilities

Psychotropic medications are used regularly to manage problem behaviours among people with intellectual disabilities. This causes concern because often these medications are used out of their licensed indications in this context. The WPA Section on Psychiatry of Intellectual Disability has recently developed an evidence and consensus-based international guide for practitioners for the use of psychotropic medications for problem behaviours among adults with intellectual disabilities. This guide advises on assessment of behaviours, producing a formulation, initiation of treatment, assessment of out-come and adverse effects, follow-up arrangements, and possibility of discontinuation of treatment.     

OBSERVATIONS ON NOCTULE BATS (NYCTALUS NOCTULA) CAPTURED WHILE FEEDING

In the summer and early autumn of 1960, 1961 and 1962, noctule bats flying low, taking house crickets as these flew from a municipal rubbish tip, were captured in mist nets, ringed, released and in many cases recaptured a number of times. The flying bats showed no fear of human beings or predatory birds and did not learn to avoid the net. In June and July of each year the majority of bats caught were adult females, the flying young of the year first appearing in August though some did not fly until September and October. Young males did not reach sexual maturity in the year of their birth, though five out of fourteen females recaptured at a year old did. There was a considerable movement of adult males in the late summer, adult bats being captured in approximately equal numbers of both sexes during August and September. In October the females seemed to disappear, the majority of the bats caught during that month being males: by November the crickets had ceased to fly and no more bats could be captured though a few wero still flying on warm nights. There was a marked difference in feeding behaviour over these three years, the bats concentrating more on crickets in 1960 than in 1961 and 1962. Though the differences are not statistically significant there were indications of an increase in body weight between July and October in the years when less cricket feeding was occurring. About 50 per cent of the females captured in each of the years 1960 and 1961 were recaptured feeding on the same site in the following year: the recovery rate of males was about 30 per cent in 1961, 60 per cent in 1962.     

Electron microscopy mapping of oligopurine tracts in duplex DNA by peptide nucleic acid targeting.

Biotinylated homopyrimidine decamer peptide nucleic acids (PNAs) are shown to form sequence-specific and stable complexes with complementary oligopurine targets in linear double-stranded DNA. The noncovalent complexes are visualized by electron microscopy (EM) without chemical fixation using streptavidin as an EM marker. The triplex stoichiometry of the PNA-DNA complexes (two PNA molecules presumably binding by Watson-Crick and Hoogsteen pairing with one of the strands of the duplex DNA) is indicated by the appearance of two streptavidin 'beads' per target site in some micrographs, and is also supported by the formation of two retardation bands in a gel shift assay. Quantitative analysis of the positions of the streptavidin 'beads' revealed that under optimized conditions PNA-DNA complexes are preferably formed with the fully complementary target. An increase in either the PNA concentration or the incubation time leads to binding at sites containing one or two mismatches. Our results demonstrate that biotinylated PNAs can be used for EM mapping of short targets in duplex DNA.