Chemistry for Sustainable Development 16 (2008) 143-153 Composition and Physicochemical Properties of Natural Blue Clays

Abstract Physical and chemical features of natural clays have been studied using the methods of X-ray diffraction, chemical, thermal and spectral analyses, ESR and IR spectroscopy; the nature of their medical properties being considered. The composition of macro and trace impurities in the clays has been analysed. The medical properties of the clays are determined by the presence of almost all the chemical elements necessary for normal functioning of a living organism as well as by sorption features due to a specific character of crystal structure. Using ESR technique, the forms of occurrence for some trace impurities (Mn 2+ , Fe 3+ ) and for paramagnetic centers (PC) of the radiation nature have been determined. The intensity of PC response has been shown to correlate with the content of actinoid ions such as U and Th in the samples. Basing on the ESR spectral data it has been established that blue color of the clays is caused by V 4+ impurity ions V 4+ in the form of vanadyl VO 2+ . The content of the microelements such as vanadium, boron and chromium in blue kaoline ãëèíàõ has been demonstrated to be 10-15 times higher as compared to clay samples of another coloring. An important role of complex influence of macro-and microelements (silicon-boron, vanadium-chromium, manganese, etc.) on the enzymes and hormones in various organs, as well as the presence of such combinations of chemical elements in blue clays have been noted

Coligomerization of Styrene and a-Methylstyrene Catalyzed by y Zeolites

It is ascertained that during the interaction of styrene and -methylstyrene in the presence of cation and cation-decationated forms of zeolite Y the activity of zeolite catalysts increases in the following order: NiNaY CaNaY <LaNaY 0,5 NY <La Y <NiHY 0,96 Y. The product of reaction in the presence of cation forms of zeolite (NiNaY, CaNaY, LaNaY) is a mixture of low-molecular (n=2 - 4) and high-molecular oligomers (n=14). Oligomers with the degree of oligomerization 2 - 8 are formed in the presence of other zeolite samples. Zeolites 0,96 Y and NiHY allow to receive gomo - and codimers with selectivity 68-80%. The main product of codimerization is cyclic dimer 1,1 – dimethyl – 3-phenylindane

Small Scale Anisotropy Predictions for the Auger Observatory

We study the small scale anisotropy signal expected at the Pierre Auger Observatory in the next 1, 5, 10, and 15 years of operation, from sources of ultra-high energy (UHE) protons. We numerically propagate UHE protons over cosmological distances using an injection spectrum and normalization that fits current data up to \sim 10^{20}\eV. We characterize possible sources of ultra-high energy cosmic rays (UHECRs) by their mean density in the local Universe, $\bar{\rho} = 10^{-r}$ Mpc$^{-3}$, with $r$ between 3 and 6. These densities span a wide range of extragalactic sites for UHECR sources, from common to rare galaxies or even clusters of galaxies. We simulate 100 realizations for each model and calculate the two point correlation function for events with energies above 4 \times 10^{19}\eV and above 10^{20}\eV, as specialized to the case of the Auger telescope. We find that for r\ga 4, Auger should be able to detect small scale anisotropies in the near future. Distinguishing between different source densities based on cosmic ray data alone will be more challenging than detecting a departure from isotropy and is likely to require larger statistics of events. Combining the angular distribution studies with the spectral shape around the GZK feature will also help distinguish between different source scenarios.Comment: 15 pages, 6 figures, 6 tables, submitted to JCA

Evidence for vortex staircases in the whole angular range due to competing correlated pinning mechanisms

We analyze the angular dependence of the irreversible magnetization of YBa$_2$Cu$_3$O$_7$ crystals with columnar defects inclined from the c-axis. At high fields a sharp maximum centered at the tracks' direction is observed. At low fields we identify a lock-in phase characterized by an angle-independent pinning strength and observe an angular shift of the peak towards the c-axis that originates in the material anisotropy. The interplay among columnar defects, twins and ab-planes generates a variety of staircase structures. We show that correlated pinning dominates for all field orientations.Comment: 9 figures, 4 figure

GZK Photons Above 10 EeV

We calculate the flux of "GZK-photons", namely the flux of photons produced by extragalactic nucleons through the resonant photoproduction of pions, the so called GZK effect. This flux depends on the UHECR spectrum on Earth, of the spectrum of nucleons emitted at the sources, which we characterize by its slope and maximum energy, on the distribution of sources and on the intervening cosmological backgrounds, in particular the magnetic field and radio backgrounds. For the first time we calculate the GZK photons produced by nuclei. We calculate the possible range of the GZK photon fraction of the total UHECR flux for the AGASA and the HiRes spectra. We find that for nucleons produced at the sources it could be as large as a few % and as low as 10^{-4} above 10 EeV. For nuclei produced at the sources the maximum photon fraction is a factor of 2 to 3 times smaller above 10 EeV but the minimum could be much smaller than for nucleons. We also comment on cosmogenic neutrino fluxes.Comment: 20 pages, 9 figures (21 panels), iopart.cls and iopart12.clo needed to typese

MORPHOGENESIS OF KNEE HYALINE CARTILAGE DURING INTRAARTICULAR INJECTION OF PLATELET-RICH AUTOLOGOUS PLASMA AND/OR HYALURONIC ACID PREPARATION IN RATS WITH EXPERIMENTAL OSTEOARTHRITIS

According to current concepts, the influence of autologous platelet-rich plasma (PRP) and high molecular hyaluronates (HA) on the repair of hyaline cartilage during its inflammatory and degenerative changes has been insufficiently studied yet. The objective of the work was to evaluate the morphological changes in the structure of hyaline cartilage in experimental osteoarthritis after intra-articular injection of PRP and/or HA. Material and methods. The authors used 50 adult rats of Wistar line, weighing 250±2,2 g., distributed into five groups of 10 animals (two control and three experimental groups). An experimental gonarthosis was simulated on four groups of animals. Animals of the first experimental group received intra-articular injection of PRP, the second group – HA, the third – both PRP and HA. Results. No morphological signs of degenerative and inflammatory changes in the first control group were identified. Following osteoarthritis simulation the articular cartilage thinned to 121±20,4 microns (p&lt;0,05) and the volume fraction of chondrocyte decreased to 1,2±0,6% (p&lt;0,05). The authors observed an uneven coloration of collagen fibers with severe tinctorial properties disorder of the articular cartilage matrix. After the RPR introduction the authors observed tickening of the articular cartilage up to 275±18,9 micron (p&lt;0,05) and the volume fraction of chondrocytes up to 18,4±2,0% (p&lt;0,05). The contour of the cartilage surface became smoother with the formation of a cell-free zone. Collagen fibers demonstrated a uniform distribution, tinctorial properties of cartilage matrix in all areas were preserved, no signs of inflammation were noted. After HA introduction the authors observed thickening of the cartilage plate up to 264±21,3 microns (p&lt;0,05) and the volume fraction of chondrocytes up to 11,6±1,2% (p&lt;0,05). The surface of the cartilage featured uneven contours due to multiple areas of pulping. Uneven tinctorial properties of cartilage matrix, thickness and orientation of collagen fibres were retained. No signes of inflammation were observed. After the combined consecutive application of PRP and HA cartilage thickness increased up to 268±15,3 microns (p&lt;0,05) and the volume fraction of chondrocytes increased up to 12,7±0,9% (p&lt;0,05). Individual portions of pulping on the cartilage surface were observed. Tinctorial properties of the cartilage matrix were preserved; the focal uneven staining of collagen fibers in the basal zone was observed. No signs of inflammation were noted. Conclusion. During osteoarthritis simulation in knee joints of experimental Wistar line rats the authors observed severe structural changes in articular hyaline cartilage including complete destruction accompanied by vascular proliferation and granulomatous inflammation. Intraarticular injections of PRP, HA as well as PRP in combination with HA during the simulation of osteoarthrosis were accompanied by a decrease in the severity of degenerative and dystrophic processes and improval of tinctorial properties of articular cartilage matrix. Sole application of PRP or consecutive application of PRP followed by HA were observed as having the more significant reparative effect on articular cartilage as compared to HA

Composition of UHECR and the Pierre Auger Observatory Spectrum

We fit the recently published Pierre Auger ultra-high energy cosmic ray spectrum assuming that either nucleons or nuclei are emitted at the sources. We consider the simplified cases of pure proton, or pure oxygen, or pure iron injection. We perform an exhaustive scan in the source evolution factor, the spectral index, the maximum energy of the source spectrum Z E_{max}, and the minimum distance to the sources. We show that the Pierre Auger spectrum agrees with any of the source compositions we assumed. For iron, in particular, there are two distinct solutions with high and low E_{max} (e.g. 6.4 10^{20} eV and 2 10^{19} eV) respectively which could be distinguished by either a large fraction or the near absence of proton primaries at the highest energies. We raise the possibility that an iron dominated injected flux may be in line with the latest composition measurement from the Pierre Auger Observatory where a hint of heavy element dominance is seen.Comment: 19 pages, 6 figures (33 panels)- Uses iopart.cls and iopart12.clo- In version 2: addition of a few sentences and two reference

Comparison of the In-plane Thermal and Electrical Conductivities and Transverse Pull Strengths of Various Pyrolytic Graphite Materials

Different pyrolytic graphite materials were produced varying the annealing parameters such as temperature, pressure and time. These variations should alter the product properties in a systematic way. The coefficient of in-plane thermal conductivity, C_KT, the coefficient of electrical conductivity, $\sigma$ and the pull strength S of these samples were measured. Results for the different materials and correlations are reporte