Thermal Behavior of Alkali Zinc Phosphates

Alkali zinc phosphates Na₂ZnP₂O₇, K₂ZnP₂O₇, LiNaZnP₂O₇, LiKZnP₂O₇, NaKZnP₂O₇, and Li₁₂Zn₄(P₂O₇)₅, which can be prepared both by the solid-phase synthesis and through crystallization from a glass, are studied using high-temperature X-ray powder diffraction. The unit cell parameters as functions of the temperature in the range 20–700°C are analyzed, and the linear anisotropic thermal expansion coefficients are determined. The majority of these compounds are characterized by strong anisotropy of thermal expansion. It is found that the LiKZnP₂O₇ compound exists in two polymorphic modifications, namely, the low-temperature monoclinic modification and the high-temperature orthorhombic modification.     

Burning clinker for high-alumina cement in a rotary kiln

Conclusions We prepared clinker for high-alumina cement in a rotary kiln and determined the material balance in firing when preparing the raw mixtures with two methods: granulation in a plate granulator and briquetting on a roller press. It is shown that much less dust removal (4%) is ensured by firing the briquets obtained on the roller press. The aluminous cement obtained with this technology has a high graded strength.Translated from Ogneupory, No. 6, pp. 34–36, June, 1987.     

Histones associated with non-nucleosomal rat ribosomal genes are acetylated while those bound to nucleosome-organized gene copies are not

Acetylation of histones bound to rat rRNA genes has been studied relative to their organization in chromatin, either as canonical nucleosomes, containing the inactive copies, or as anucleosomal nonrepeating structures, corresponding to the transcribed genes (Conconi, A., Widmer, R. M., Koller, T., and Sogo, J. M. (1989) Cell 57, 753-761). Nuclei from butyrate-treated rat tumor cells were irradiated with a UV laser to cross-link proteins to DNA, and the purified covalent complexes were immunofractionated by an antibody that specifically recognized the acetylated histones. Upon probing with sequences coding for mature rat 28 S RNA, DNA of the antibody-bound complexes was 5-20-fold enriched relative to the total rat DNA. Since the laser cross-links histones to DNA in both active and inactive genes, one cannot distinguish which one of them, or both, are bound to acetylated histones. Alternatively, purified mononucleosomes were immunofractionated, but DNA from the antibody-bound monosomes was not enriched in coding rDNA. Taken together, these results suggest that nucleosome-organized rRNA genes are bound to nonmodified histones and that the acetylated histones are associated with the active, anucleosomal gene copies.     

Optimization of the composition of nitridic ceramic tool material by tribotechnical tests

Translated from Poroshkovaya Metallurgiya, No. 4, pp. 46–51, April, 1992.     

Examples of recapitulation of the phylogenetic stages of development of the wakefulness-sleep cycle in mammalian ontogenesis

The purpose of this study was to determine the relationship between the ulnar nerve and the cubital tunnel during flexion of the elbow with use of magnetic resonance imaging and measurements of intraneural and extraneural interstitial pressure. Twenty specimens from human cadavera were studied with the elbow in positions of incremental flexion. With use of magnetic resonance imaging, cross-sectional images were made at each of three anatomical regions of the cubital tunnel: the medial epicondyle, deep to the cubital tunnel aponeurosis, and deep to the flexor carpi ulnaris muscle. The cross-sectional areas of the cubital tunnel and the ulnar nerve were calculated and compared for different positions of elbow flexion. Interstitial pressures were measured with use of ultrasonographic imaging to allow a minimally invasive method of placement of the pressure catheter, both within the cubital tunnel and four centimeters proximal to it, at 10-degree increments from 0 to 130 degrees of elbow flexion. As the elbow was moved from full extension to 135 degrees of flexion, the mean cross-sectional area of the three regions of the cubital tunnel decreased by 30, 39, and 41 per cent and the mean area of the ulnar nerve decreased by 33, 50, and 34 per cent. These changes were significant in all three regions of the cubital tunnel (p < 0.05). The greatest changes occurred in the region beneath the aponeurosis of the cubital tunnel with the elbow at 135 degrees of flexion. The mean intraneural pressure within the cubital tunnel was significantly higher than the mean extraneural pressure when the elbow was flexed 90, 100, 110, and 130 degrees (p < 0.05). With the elbow flexed 130 degrees, the mean intraneural pressure was 45 per cent higher than the mean extraneural pressure (p < 0.001). Similarly, with the elbow flexed 120 degrees or more, the mean intraneural pressure four centimeters proximal to the cubital tunnel was significantly higher than the mean extraneural pressure (p < 0.01). Relative to their lowest values, intraneural pressure increased at smaller angles of flexion than did extraneural pressure, both within the cubital tunnel and proximal to it. With the numbers available, we could not detect any significant difference in intraneural pressure measured, either at the level of the cubital tunnel or four centimeters proximal to it, after release of the aponeurotic roof of the cubital tunnel.     

Safety of bacteria of the genus Bacillus, forming the base of some probiotics]

The study of the safety of bacillary strains forming the base of new probiotics (biosporin and subalin) was made. For control, the safety of Bacillus sp. IP5832 (the base of the preparation of bactisubtil) was studied. The results obtained in this investigation demonstrated that the strains contained in biosporin and subalin were safe when injected intravenously and intraperitoneally into animals in dose of 5 x 10(9) cells per 0.5 ml of physiological saline. The introduction of Bacillus sp. IP5832 in the same dose produced 100% lethal effect.