Variations in the Proportion of Glycolytic/Non-glycolytic Energy Substrates Modulate Sperm Membrane Integrity and Function in Diluted Boar Samples Stored at 15–17°C

In this work the role of energy substrates in the maintenance of boar-sperm survival during storage at 15-17 degrees C was tested. For this purpose, boar spermatozoa were stored at 15-17 degrees C in several defined media with separate combinations of a monosaccharide, glucose and a non-monosaccharide, either citrate or lactate, energy substrates. Our results indicate that the medium containing the highest concentration of glucose together with low lactate levels was the most suitable to maintain sperm quality for 168 h at 15-17 degrees C. This was confirmed after observation of the results of the percentages of viability and altered acrosomes, the osmotic resistance test, the hyperosmotic resistance test and the rhythm of L-lactate production. The survival ability of boar sperm was greater in this experimental medium than in the standard Beltsville Thawing Solution extender, which contains only glucose as an energy substrate, although at a concentration far higher than that of all the tested experimental media. Our results indicate that the exact composition, more than the pure quantity of energy substrates, is a very important modulatory factor which affects survival ability of boar sperm in refrigeration. Thus, the exact combination of several energy substrates would have to be taken into account when optimizing the design of commercial extenders to store boar spermatozoa at 15-17 degrees C.     

Experimental detection of tetranitrogen

Tetranitrogen (N4), which has been the subject of great theoretical interest, has been prepared from the N4+ cation and positively detected as a gaseous metastable molecule with a lifetime exceeding 1 microsecond in experiments based on neutralization-reionization mass spectrometry. An examination of the geometry of N4+ and the fragmentation pattern of the (14)N2(15)N2 neutral molecule has revealed that the latter is characterized by an open-chain geometry with two distinct, closely bound N2 units joined by a longer weaker bond.     

Dermal and serological response against Pseudomonas aeruginosa in sheep bred for resistance and susceptibility to fleece-rot

Genetically select lines of Merino sheep have been bred at Trangie (NSW Agriculture and Fisheries) for resistance (R) or susceptibility (S) to fleece-rot and flystrike. It is believed that fleece characters are primarily responsible for the R or S phenotype. When transferred to the wetter coastal environment of Sydney, R and S sheep with no more than 6 weeks wool cover, continued to show significant differences in the incidence and severity of fleece-rot dermatitis. To test the hypothesis that these sheep might also exhibit differences in their local skin reactions and immune responsiveness, 3 intradermal injections of killed Pseudomonas aeruginosa were administered at monthly intervals. After primary intradermal challenge, R sheep had a higher incidence of skin induration and a stronger inflammatory response (increased induration diameter) than S sheep. Compared to S sheep, R sheep also developed higher levels of circulating antibodies against whole cell antigen and both inner and outer membrane proteins of P. aeruginosa. These responses were maintained in R sheep with each consecutive challenge while S sheep showed a decline in their immune responsiveness. Differences in antibody response against outer membrane proteins were also detected when antigenically naive sheep from each genetic line were sensitised by epicutaneous challenge with P. aeruginosa under experimental wetting conditions. Intradermal challenge of these animals 6 months later with outer membrane proteins, revealed a late maximum (72 h) in the development of induration diameters for R sheep while S animals showed maximal induration diameters by 24 h. However, there was no significant difference in induration response between 24 h and 72 h within each group of sheep.(ABSTRACT TRUNCATED AT 250 WORDS)     

Protonated Ozone: Experimental Detection of O3H+ and Evaluation of the Proton Affinity of Ozone

The elusive protonated ozone ion (O(3)H(+)) has been long postulated as a reactive intermediate but never experimentally observed. This ion has been detected here in mass spectrometric experiments with the use of Fourier transform ion cyclotron resonance. In these experiments, ozone (O(3)) was protonated by strong acids-for example, H(3)(+), KrH(+), XeH(+), and CH(5)(+). The hitherto experimentally unknown proton affinity of O(3) was evaluated by a "bracketing" technique and determined to be 148 -/+ 3 kilocalories mole(-1) at 298 kelvin, in excellent agreement with a value determined in a recent theoretical study of the O(3)/O(3)H(+) system, which was 148 kilocalories mole(-1) at zero temperature ( approximately 149.5 kilocalories mole(-1) at 298 kelvin).     

Reconstruction of Current Flow and Imaging of Current-Limiting Defects in Polycrystalline Superconducting Films

Magneto-optical imaging was used to visualize the inhomogeneous penetration of magnetic flux into polycrystalline TlBa2Ca2Cu3Ox films with high critical current densities, to reconstruct the local two-dimensional supercurrent flow patterns and to correlate inhomogeneities in this flow with the local crystallographic misorientation. The films have almost perfect c-axis alignment and considerable local a- and b-axis texture because the grains tend to form colonies with only slightly misaligned a and b axes. Current flows freely over these low-angle grain boundaries but is strongly reduced at intermittent colony boundaries of high misorientation. The local (<10-micrometer scale) critical current density Jc varies widely, being up to 10 times as great as the transport Jc (scale of approximately 1 millimeter), which itself varies by a factor of about 5 in different sections of the film. The combined experiments show that the magnitude of the transport Jc is largely determined by a few high-angle boundaries.     

Extraction of anthocyanins and other phenolics from black currants with sulfured water

Health benefits of fruits, vegetables, and red wine are attributed to anthocyanins and other phytochemicals. In this research, the extraction of phenolics from black currants was optimized using different SO(2) concentrations (28, 300, 700, 1100, and 1372 ppm), temperatures (6, 20, 40, 60, and 74 degrees C), and solvent to solid ratios (S/S) (6, 20, 40, 60, and 74 mL/g). Surface response methodology was used to optimize yields of anthocyanins and total phenolics, as well as their antiradical and antioxidant activities. The extraction of phenolics varied with the SO(2) concentration, S/S, and temperature. Maximum yields of total phenolics and anthocyanins were obtained at an SO(2) concentration of 1000-1200 ppm and 19 L of solvent/kg of milled frozen berries. The increase of extraction temperature increased the rate of extraction and, thus, times to reach equilibrium for the extraction of total phenolics and anthocyanins were reduced. However, for the extraction of anthocyanins it is recommended that temperatures of 30-35 degrees C be used, as higher temperatures will degrade these compounds. Antioxidant activity was affected by all three experimental variables evaluated; however, the main variable affecting it was S/S. The higher the S/S, the lower the antioxidant index.     

Systemic antibacterial drug use in dogs in Australia

A survey of veterinarians' use of antibacterial drugs was conducted by distributing a questionnaire to Australian practitioners. Respondents were asked to indicate their general patterns of use of various systemic antibacterial drugs and drug combinations in dogs and their approach to certain specified clinical disorders. Overall, antibacterials of the p-lactam type (penicillins and cephalosporins) were most commonly used. Other antibacterials with substantial use were doxycycline, sulphonamide-trimethoprim, metronidazole, fluoroquinolones and clindamycin. Drug selection for different disorders was generally appropriate when compared with recommendations in recent texts, although inappropriate use was evident in some circumstances.