Determination of lubricant selection based on elastohydrodynamic film thickness and traction measurement

The project was conducted to aid in the development of an elastohydrodynamic specification for military lubricants. Experiments were conducted with a rolling disk apparatus designed to simulate a bearing or gear type contact. Measurements included lubricant film thickness, lubricant breakdown and traction for a range of loads, speeds, temperatures, and surface roughnesses. Several lubricants were used in the investigations including a traction fluid, two synthetic paraffinic lubricants and several lubricants conforming to MIL-L 7808 and 23699 specifications. Recommendations regarding an EHD specification are included

Effect of longitudinal surface finish on elastohydrodynamic lubrication

The effect of longitudinal-lay surface finish on the elastohydrodynamic film thickness and the percentage of film between rolling disks in contact were evaluated using a rolling disk apparatus. Film thickness was measured by transmitted X-rays, and percentage of film was monitored by an alternating-current continuity circuit. Disk finish was varied on both the crowned upper disk and the cylindrical lower disk. A type-2 ester and a synthetic paraffinic oil were used as lubricants. It was shown that the roughness with longitudinal lay has a deleterious effect on both film thickness and percentage of film. Measured film thicknesses for the two lubricants were comparable at equivalent test conditions. The percentage of film where a change in surface topography was observed was approximately 20 percent for the synthetic paraffinic oil and 10 percent for the type-2 ester

Guidelines for composite materials research related to general aviation aircraft

Guidelines for research on composite materials directed toward the improvement of all aspects of their applicability for general aviation aircraft were developed from extensive studies of their performance, manufacturability, and cost effectiveness. Specific areas for research and for manufacturing development were identified and evaluated. Inputs developed from visits to manufacturers were used in part to guide these evaluations, particularly in the area of cost effectiveness. Throughout the emphasis was to direct the research toward the requirements of general aviation aircraft, for which relatively low load intensities are encountered, economy of production is a prime requirement, and yet performance still commands a premium. A number of implications regarding further directions for developments in composites to meet these requirements also emerged from the studies. Chief among these is the need for an integrated (computer program) aerodynamic/structures approach to aircraft design

Mapping of serotype-specific, immunodominant epitopes in the NS-4 region of hepatitis C virus (HCV):use of type-specific peptides to serologically differentiate infections with HCV types 1, 2, and 3

The effect of sequence variability between different types of hepatitis C virus (HCV) on the antigenicity of the NS-4 protein was investigated by epitope mapping and by enzyme-linked immunosorbent assay with branched oligopeptides. Epitope mapping of the region between amino acid residues 1679 and 1768 in the HCV polyprotein revealed two major antigenic regions (1961 to 1708 and 1710 to 1728) that were recognized by antibody elicited upon natural infection of HCV. The antigenic regions were highly variable between variants of HCV, with only 50 to 60% amino acid sequence similarity between types 1, 2, and 3. Although limited serological cross-reactivity between HCV types was detected between peptides, particularly in the first antigenic region of NS-4, type-specific reactivity formed the principal component of the natural humoral immune response to NS-4. Type-specific antibody to particular HCV types was detected in 89% of the samples from anti-HCV-positive blood donors and correlated almost exactly with genotypic analysis of HCV sequences amplified from the samples by polymerase chain reaction. Whereas almost all blood donors appeared to be infected with a single virus type (97%), a higher proportion of samples (40%) from hemophiliacs infected from transfusion of non-heat-inactivated clotting factor contained antibody to two or even all three HCV types, providing evidence that long-term exposure may lead to multiple infection with different variants of HCV

Suppression of eukaryotic initiation factor 4E prevents chemotherapy-induced alopecia

BACKGROUND: Chemotherapy-induced hair loss (alopecia) (CIA) is one of the most feared side effects of chemotherapy among cancer patients. There is currently no pharmacological approach to minimize CIA, although one strategy that has been proposed involves protecting normal cells from chemotherapy by transiently inducing cell cycle arrest. Proof-of-concept for this approach, known as cyclotherapy, has been demonstrated in cell culture settings. METHODS: The eukaryotic initiation factor (eIF) 4E is a cap binding protein that stimulates ribosome recruitment to mRNA templates during the initiation phase of translation. Suppression of eIF4E is known to induce cell cycle arrest. Using a novel inducible and reversible transgenic mouse model that enables RNAi-mediated suppression of eIF4E in vivo, we assessed the consequences of temporal eIF4E suppression on CIA. RESULTS: Our results demonstrate that transient inhibition of eIF4E protects against cyclophosphamide-induced alopecia at the organismal level. At the cellular level, this protection is associated with an accumulation of cells in G1, reduced apoptotic indices, and was phenocopied using small molecule inhibitors targeting the process of translation initiation. CONCLUSIONS: Our data provide a rationale for exploring suppression of translation initiation as an approach to prevent or minimize cyclophosphamide-induced alopecia.1U01 CA168409 - NCI NIH HHS; P01 CA 87497 - NCI NIH HHS; P30 CA008748 - NCI NIH HHS; MOP-106530 - Canadian Institutes of Health Research; P01 CA013106 - NCI NIH HH

Exact solutions and stability of rotating dipolar Bose-Einstein condensates in the Thomas-Fermi limit

We present a theoretical analysis of dilute gas Bose-Einstein condensates with dipolar atomic interactions under rotation in elliptical traps. Working in the Thomas-Fermi limit, we employ the classical hydrodynamic equations to first derive the rotating condensate solutions and then consider their response to perturbations. We thereby map out the regimes of stability and instability for rotating dipolar Bose-Einstein condensates and in the latter case, discuss the possibility of vortex lattice formation. We employ our results to propose several novel routes to induce vortex lattice formation in a dipolar condensate.Comment: 12 pages with 6 figure