The interactions of anti-nucleons in complex nuclei

The interactions of antinucleons in complex nuclei of emulsion have been studied. The three main lines of investigation are the following: 1) The annihilation at rest of antiprotons in the complex nuclei of emulsion has been studied and a method has been devised of separating the annihilations in the light and the heavy elements. By identifying the annihilations on the neutrons and protons in light elements it is shown that the ratio of the probabilities of annihilation proceeds equally through the singlet and triplet isospin channels. The apparent departures from this result for heavy elements have been accounted for by the secondary interactions of the annihilation products in the parent nuclei. 2) The antiproton is used as a nuclear probe to determine the distribution of memento of the nucleons of light elements such as carbon. It is found that the momenta of the nucleons of light elements such as carbon. It is found that the momenta follow the distribution expected from a harmonic oscillator model of the nucleus as found by other techniques and that these momenta extend up to about 400 MeV/c. 3) The interactions of antineutrons produced by the charge exchange of antiprotons with the emulsion nuclei have been studied and it has been shown that the general characteristics of the antineutron stars such as the sizes, the mean multiplicities of secondary mesons and their energy spectra are similar to those of antiproton stars. Finally, the charge exchange cross-section for antiprotons of moan energy 125 MeV has been determined and is found to be (17 ± 6) mb. This is close to the value expected from the calculations made for the charge exchange cross-section of antiprotons in complex nuclei

Sperm Genetic and Epigenetic Mechanisms Regulating Male Fertility

Male fertility, ability to fertilize and activate the egg and support early embryo development, is crucial for mammalian reproduction and development. Testis specific histone 2B (TH2B) of sperm, protamines (PRM1/2), and posttranslational modifications of histone 3 (H3K27me3 and H3k27ac) are involved in spermatogenesis and male fertility. However, molecular and cellular mechanisms by which TH2B regulates histone to protamine replacement is poorly defined. Immunocytochemistry, western blotting, flow cytometry, computer-assisted sperm analysis (CASA) and bioinformatic approaches were applied to analyze sperm from Holstein bulls with different in vivo fertility. Results from the immunocytochemistry experiments showed that while TH2B and H3K27me3 were localized predominantly at the equatorial and post acrosomal (localized as a crown around the sperm head) parts, respectively. The H3K27ac was also detectable in the bovine sperm head. Signal intensities of TH2B (mean ± SEM) were higher in sperm from the low fertility bulls (220.56 ± 9.20) as compared to those from the high fertility bulls (198.39 ± 10.0). Signal intensities of H3K27me3 (16.25 ± 1.69) were significantly different than those of H3K27ac (4.74 ± 0.88) in bull spermatozoa. Using the bioinformatic tools, including Clustal Omega, Cytoscape, Emboss Dotmatcher, InterProScan, and STRING, we demonstrated that TH2B has the conserved histone H2B domain which has a strong association with proteins involved in chromosome organization and histone ubiquitination. Intensities of PRM1 and PRM2 were significantly associated with one another (p \u3c 0.0001), but neither were significantly associated with fertility. Results from CASA revealed significant differences between high and low fertility bulls regarding average sperm pathway velocity, amplitude of lateral head displacement and straightness (p \u3c 0.05). The interacting proteins of H3 are involved in subcellular processes such as regulation of H3K27 methylation, nucleosome assembly, regulation of DNA replication, and chromatin assembly. These results are significant because they help advance fundamental knowledge in sperm physiology involving epigenetic and genetic determinants. The new knowledge can be used to enhance reproductive biotechnology to improve fertility. In addition, the data generated using the unique bull model can be applied to study mammalian reproduction and development due to similarities in genetics and physiology between bovine and other mammals

Prevention of corrosion with polyaniline

Methods for improving the corrosion inhibition of a metal or metal alloy substrate surface are provided wherein the substrate surface is coated with a polyaniline film. The polyaniline film coating is applied by contacting the substrate surface with a solution of polyaniline. The polyaniline is dissolved in an appropriate organic solvent and the solvent is allowed to evaporate from the substrate surface yielding the polyaniline film coating