Evidence for plastic deformation in the natural polycrystalline diamond,framesite

Relief-polished striations have been found within grains in polished sections of framesite, a naturally occurring polycrystalline diamond. Because the narrow zones represented by these surface striations are harder than any orientation of the matrix (as revealed by abrasion resistance) and because they etch preferentially, they have been interpreted as representing oriented deformation bands within the grains. It is concluded that the microstructure of framesite is the result of plastic deformation of diamond grains probably under conditions such that brittle fracture was inhibited.     

Numerical approach to hopping conduction

A numerical method for calculation of the polarization conductivity has been developed. This approach has been applied to the correlated barrier hopping (CBH) and quantum mechanical tunnelling (QMT) models in the case of monoelectronic hops. These calculations have been performed on well-known solids such as carbon (HTT 600° C) and badly organized molybdenum and tungsten sulphides. The agreement between theory and experimental results is more satisfying than in a previous approach. The parametersW _M andN ₀ are determined for the CBH model, andN(E _F) for the QMT model.     

Order vs. Disorder: Cholesterol and Omega-3 Phospholipids Determine Biomembrane Organization

Lipid structural diversity strongly affects biomembrane chemico-physical and structural properties in addition to membrane-associated events. At high concentrations, cholesterol increases membrane order and rigidity, while polyunsaturated lipids are reported to increase disorder and flexibility. How these different tendencies balance in composite bilayers is still controversial. In this study, electron paramagnetic resonance spectroscopy, small angle neutron scattering, and neutron reflectivity were used to investigate the structural properties of cholesterol-containing lipid bilayers in the fluid state with increasing amounts of polyunsaturated omega-3 lipids. Either the hybrid 1-stearoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine or the symmetric 1,2-docosahexaenoyl-sn-glycero-3-phosphocholine were added to the mixture of the naturally abundant 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine and cholesterol. Our results indicate that the hybrid and the symmetric omega-3 phospholipids affect the microscopic organization of lipid bilayers differently. Cholesterol does not segregate from polyunsaturated phospholipids and, through interactions with them, is able to suppress the formation of non-lamellar structures induced by the symmetric polyunsaturated lipid. However, this order/disorder balance leads to a bilayer whose structural organization cannot be ascribed to either a liquid ordered or to a canonical liquid disordered phase, in that it displays a very loose packing of the intermediate segments of lipid chains.     

Near-Complete Remission of Glioblastoma in a Patient Treated with an Allogenic Dendritic Cell-Based Vaccine: The Role of Tumor-Specific CD4+T-Cell Cytokine Secretion Pattern in Predicting Response and Recurrence

Immunotherapy has brought hope to the fight against glioblastoma, but its efficacy remains unclear. We present the case of CST, a 25-year-old female patient with a large right-hemisphere glioblastoma treated with a dendritic–tumor cell fusion vaccine. CST showed a near-complete tumor response, with a marked improvement in her functional status and simultaneous increases in tumor-specific CD8+ and CD4+ T cells. Two months before recurrence, the frequency of tumor-specific T cells decreased, while that of IL-17 and CD4+ T cells increased. CST passed away 15 months after enrollment. In this illustrative case, the tumor-specific CD4+ T-cell numbers and phenotype behaved as treatment efficacy biomarkers, highlighting the key role of the latter in glioblastoma immunotherapy.     

The Determination of the Effective Shear Rate in the Brabender Viscograph and in other Systems of Complex Geometry

The effective shear rate in the Brabender Viscograph has been determined as 40 sec⁻¹ when used for fluids having equivalent Newtonian viscosities in the range 1–30 poise. This shear rate is close to that used in the mouth and implies that rankings of viscosity derived from Brabender readings will agree with sensory consistency judgements. The instrument can, therefore, be reliably used for quality control and be quoted in purchasing specifications. The methodology described can often be used in other situations for assessing an effective shear rate where the geometry of the system precludes calculation e.g. spreadability determinations and extrusion from metal tubes.     

New Group-Contribution Method for Predicting Temperature-Dependent Properties of Pure Organic Compounds

A new method for predicting temperature-dependent properties of organic compounds is presented. It is a combination of a group-contribution method with the novel non-random hydrogen-bonding (NRHB) equation-of-state theory. First-order and second-order groups are used to predict the three characteristic scaling constants of the NRHB model. With these scaling constants, one is able to estimate/predict temperature-dependent properties of pure organic compounds such as vapor pressure, liquid density, heat of vaporization and more, in a wide range of temperatures. The influence parameter, κ, which is needed for the estimation of surface tension at any given temperature, is also predicted by the same group-contribution method     

Frequency shift in signal and idler gain peaks due to nonlinear refractive index in narrow-band optical parametric oscillators

The frequency chirp in the gain spectra for the signal and idler waves in nanosecond optical parametric oscillators (OPOs) due to the nonlinear refractive index of the gain medium at the pump wavelength is discussed. Computed results for a commonly used 355 nm pumped OPO with lithium borate and beta barium borate as a gain medium show that the frequency shift remains small compared with the gain bandwith, even for a narrow-band OPO pumped above threshold.     

Microscopic Effects of Ultrasound on the Structure of Potato Starch Preliminary Study

This preliminary study has related the nature of rupture in starch grains, induced by ultrasound, to the ambient atmosphere, the concentration of the suspension, the frequency and the time of irradiation. It has been tentatively concluded that principally mechanical effects have been induced under conditions that would promote vaporous cavitation (280 KHz, 15 W/cm²). In an atmosphere of hydrogen, many deep conical pits are produced. In an atmosphere of air or oxygen, deep pitting is somewhat less pronounced than in hydrogen but injury to other parts of the surface is greater. Virtually no effect is produced in vacuo, and under carbon dioxide the effect is very weak. The extent of damage increases with time of radiation and decreases with increasing concentration of starch in the suspension. It is suggested that damage produced by ultrasound indicates a primarily radial structure of submicroscopic units in the starch grain. Explanations proposed for the effects observed must be tested in further experiments.