4,181 research outputs found
Elliptical flux vortices in YBa2Cu3O7
The most energetically favorable vortex in YBa2Cu3O7 forms perpendicular to an anisotropic plane. This vortex is elliptical in shape and is distinguished by an effective interchange of London penetration depths from one axis of the ellipse to another. By generalizing qualitatively from the isotropic to the anisotropic case, we suggest that the flux flow resistivity for the vortex that forms perpendicular to an anistropic plane should have a preferred direction. Similar reasoning indicates that the Kosterlitz-Thouless transition temperature for a vortex mediated transition should be lower if the vortex is elliptical in shape
Design considerations for lunar base photovoltaic power systems
A survey was made of factors that may affect the design of photovoltaic arrays for a lunar base. These factors, which include the lunar environment and system design criteria, are examined. A photovoltaic power system design with a triangular array geometry is discussed and compared to a nuclear reactor power systems and a power system utilizing both nuclear and solar power sources
Drug-target interactions: only the first step in the commitment to a programmed cell death?
The search for novel antitumour drugs has reached a plateau phase. The carcinomas remain almost as intractable as they did 40 years ago and the need for effective therapy is pressing. There is an argument that the current pharmacopoeia is sufficient but, to be effective, the biochemical mechanisms of drug resistance must be circumvented. In tackling the question of why certain cancer cells are resistant, the converse question of why others are sensitive still remains to be answered fully. Asking the fundamental question of why and how a cell dies may provide clues as to what avenues lie open for improved chemotherapy. In this review we survey the recent literature on cell death and we argue that it is possible that the outcome of chemotherapy may be determined by the response of the cell to the formation of the drug-target complex, and/or its sequellae, rather than to the biochemical changes brought about by the drug alone. One of these responses, determined by the phenotype of the cell, may be activation of a genetic programme for cell death
Triethylphosphite as a network forming agent enhances in-vitro biocompatibility and corrosion protection of hybrid organic-inorganic sol-gel coatings for Ti6Al4V alloys
The biocompatibility and life of metallic implants can be enhanced through improving the biocompatibility and corrosion protection characteristics of the coatings used with these materials. In this study, triethylphosphite (TEP) was used to introduce phosphorus into organic-inorganic hybrid silica based sol gel coatings prepared using γ-methacryloxypropyltrimethoxysilane and tetramethylorthosilicate. Addition of TEP dramatically increased the rate of intermolecular condensation and resulted in materials showing greater cross linking. Protein (fibrinogen) uptake, osteoblast in vitro biocompatibility and corrosion resistance was enhanced in coatings containing TEP. Although higher concentrations of phosphorus supported the greatest improvement in biocompatibility, a compromise in the phosphorus concentration used would be required if corrosion resistance was most desirable parameter for optimisation. Films prepared by dip coating on Ti6Al4V alloys from these sols offer a promising alternative to wholly metallic prostheses
A feasibility study for a remote laser water turbidity meter
A technique to remotely determine the attenuation coefficient (alpha) of the water was investigated. The backscatter energy (theta = 180 deg) of a pulse laser (lambda = 440 - 660 nm) was found directly related to the water turbidity. The greatest sensitivity was found to exist at 440 nm. For waters whose turbidity was adjusted using Chesapeake Bay sediment, the sensitivity in determining alpha at 440 nm was found to be approximately 5 - 10%. A correlation was also found to exist between the water depth (time) at which the peak backscatter occurs and alpha
A Decade Of Starspot Activity On The Eclipsing Short-Period RS Canum Venaticorum Star WY Cancri: 1988-1997
We present optical photometry of the short-period eclipsing RS CVn system WY Cancri for the years 1988–1997. For each light curve, we model the distortion waves in order to study the behavior of starspots in this system. After removing the spot effects f
Liver transplant recipients’ experiences and perspectives of a telehealth-delivered lifestyle programme A qualitative study
Introduction Dietary modification and exercise are encouraged to address cardiometabolic risk factors after solid organ transplantation. However, the lived experience of attempting positive lifestyle changes for liver transplant recipients is not known. The aim of this study was to explore the experiences of liver transplant recipients and their perspectives of a 12-week telehealth lifestyle programme and assess the feasibility of this innovative health service. Methods Focus groups and one-on-one interviews were conducted with participants who had completed a 12-week, group-based, telehealth-delivered diet and exercise programme and thematic qualitative analysis was used to code and theme the data. Results In total, 19 liver transplant recipients participated in the study (25-68 years, median time since transplant 4.4 years, 63% male). Overarching themes included: (a) 'broad telehealth advantages' which highlighted that telehealth reduced the perceived burdens of face-to-face care; (b) 'impact of employment' which identified employment as a competing priority and appeared to effect involvement with the programme; (c) 'adapting Mediterranean eating pattern to meet individual needs' which identified the adaptability of the Mediterranean diet supported by sessions with the dietitian; (d) 'increasing exercise confidence' which recognised that a tailored approach facilitated confidence and acceptability of the exercise component of the programme. Discussion A telehealth lifestyle programme delivered by dietitians and exercise physiologists is an acceptable alternative to face-to-face care that can meet the needs of liver transplant recipients. There is a need to further innovate and broaden the scope of routine service delivery beyond face-to-face consultations
Archaeological Investigations at Site 41BX66 Along Loop 1604, Bexar County, Texas
Archaeologists from the State Department of Highways and Public Transportation conducted surface collection and test excavations at Site 41BX66 in 1988 and 1989. The site, located along Loop 1604 in northern Bexar County, contained a surface scatter of lithic artifacts and fire-cracked rock. Expansion of the Loop 1604 right-of-way impacted the site area, necessitating a testing program. The results of that subsurface testing indicate that the site area of 41BX66 within the highway right-of-way (ROW) was not eligible to the National Register of Historic Places and no further work was recommended. TXDO
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