Fear of reinjury, negative affect, and catastrophizing predicting return to sport in recreational athletes with anterior cruciate ligament injuries at 1 year postsurgery.

Objective: To examine fear of reinjury, negative affect, and pain catastrophizing as determinants of athletes' confidence in their ability to take part in sport activity and their reported return to sport 1 year after undergoing anterior cruciate ligament (ACL) reconstruction. Participants: 49 recreational-level athletes (27 men and 22 women; Mage=29.15 years, SD=11.57). Results: Negative affect was inversely associated with sport confidence, and fear of reinjury was inversely associated with reported return to sport. Regression models showed that negative affect was the lone significant predictor (β=-.32, p     

CD8+ T cells clear influenza virus by perforin or Fas-dependent processes

Influenza virus infection is controlled in CD4-depleted mice that are also defective for the expression of either Fas (Fas-/-) or perforin (P-/-). Virus-immune P+/+ and P-/- CD8+ T cells can thus function in, respectively, a Fas-/- or Fas+/+ lung environment. The obvious question is whether the P-/- CD8+ set is effective in Fas-/- mice, a conclusion that would tend to favor cytokine secretion as the mode of virus clearance. Short term chimeras were made with P-/- bone marrow, P+/+ or P-/- T cells, and Fas+/+ or Fas-/- irradiated recipients. While the P+/+ CD8+ population cleared the virus from Fas+/+ and Fas-/- respiratory epithelium, the P-/- effectors were operational only if there was the potential for Fas to be expressed on radiation-resistant lung cells. Target cell destruction mediated via the Fas or perforin pathways is clearly the primary mechanism used by CD8+ T cells to terminate this viral pneumonia.     

Cytokine production in the immune response to murine gammaherpesvirus 68

Cytokine profiles were determined following intranasal infection of C57BL/6J mice with murine gammaherpesvirus 68 (MHV-68). Spleen, mediastinal, and cervical lymph node cells from infected mice produced high levels of interleukin 6 (IL-6) and gamma interferon (IFN-gamma) and lower levels of IL-2 and IL-10 following in vitro restimulation. Little or no IL-4 or IL-5 was detected. Cytokine production was generally maximal at 10 days after infection, correlating with viral clearance from the lung, although significant levels were seen as early as 3 days after administration of the virus. In vitro infection of naive splenocytes induced B-cell- dependent secretion of IL-6 and IL-10, whereas IFN-gamma and IL-2 were produced only by cells that had been primed in vivo. Depletion of B lymphocytes from primed splenocyte populations did not, however, abrogate IL-6 and IL-10 production. Highly purified immune T cells made IL-6, IL-10. and IFN-gamma following in vitro restimulation with MHV-68. Thus, IL-6 and IL-10 are components of both the acquired and the innate host response. These cytokines have potential roles in the establishment and maintenance of persistent infection.     

Alcohol use following liver transplantation for alcoholic cirrhosis

Due to the significant increase in the number of patients with alcoholic liver cirrhosis being referred for liver transplantation, studies to determine recidivism rates and influential factors affecting those rates have become increasingly crucial. Between 12/85 and 12/91, 67 patients diagnosed with alcohol related end-stage liver disease underwent orthotopic liver transplantation at Baylor University Medical Center. A 3-8 year follow-up study was conducted wherein surviving patients were contacted by phone to evaluate subsequent alcohol consumption following transplantation (with the exception of two patients whose primary physicians were contacted). Of the 67 patients transplanted, 18 had expired, 7 were alive but unavailable, and 1 had been lost to follow-up. Of the remaining 41 patients interviewed, 21 had remained abstinent, while the other 20 had returned to some form of drinking. Of patients with less than 6 months of pretransplant abstinence, only 30% remained abstinent, while the other 70% had resumed drinking. Regarding patients with at least 6 months of pretransplant abstinence, 58% had remained abstinent, while the other 42% had resumed drinking. In both groups, nearly 1/3 of those who had admitted to posttransplant drinking reported themselves as again abstinent and recommitted to sobriety when interviewed. In conclusion, 49% of patients interviewed had resumed some type of drinking following transplantation-- however, this appears not to have affected compliance or survival potential. Only 2 (4.8%) of the 41 patients interviewed had returned to excessive drinking. Thus, our findings support the use of orthotopic liver transplantation for patients with alcohol related end-stage liver disease.     

Antiviral cytotoxic activity across a species barrier in mixed xenogeneic chimeras: functional restriction to host MHC

Reconstitution of lethally irradiated mice with a mixture of mouse and rat bone marrow cells (mouse + rat-->mouse) results in mixed xenogeneic chimerism and donor-specific tolerance. The current study demonstrates that mouse and rat T lymphocytes that have developed in xenogeneic chimeras are restricted to Ag presentation by mouse, but not rat, APC. Restriction to host Ags results in functional immunocompetence with generation of antiviral cytotoxic activity in vivo, within and across species barriers. These data demonstrate for the first time that the host thymus is sufficient to support development and positive selection of functional cross-species T lymphocytes. The superior immunocompetence, as compared with fully xenogeneic (rat-->mouse) chimeras, may prove to be of significant benefit in the clinical application of xenotransplantation to solid organ transplantation and immune reconstitution for AIDS.     

Detection of rainfall rates utilizing spaceborne microwave radiometers

Over most of the microwave spectrum, raindrops both absorb and scatter radiation producing large changes in brightness temperatures relative to clear or cloudy conditions. Since the structure of rain varies substantially for different rain rates and climatological backgrounds, the raindrop size distribution, the rain-layer thickness and the ice clouds above the rain layer are all important inputs to the model computations. The subsequent modeling involves applying the Mie theory to derive the absorption and scattering effects and the radiative transfer computations to derive the brightness temperature. The radiative transfer calculation is based upon a variational iterative approach which takes account of the multiple scattering effect of the rain layer. Results over both ocean and land backgrounds are demonstrated. It is shown that over ocean background, which is “cold” in the microwave region, lower frequencies are sufficiently sensitive to rain conditions. Over land background, higher frequencies have to be utilized in order to obtain the sensitivity to rain rates. It is also demonstrated that by using discrimination tests of the radiometric data, the rain/no rain decision can be made and the rainfall rate can be retrieved from a statistical inversion technique. The shortcomings of this technique are: (1) the assumption of a homogeneous field of view at different wavelengths can be erroneous, (2) the actual physical structure of the rain layer may be significantly different from the one used in the climatological approach, and (3) the additional uncertainty which may be introduced because of the limitations of the radiative transfer algorithm.     

Block Diagonalization of the Electromagnetic Impedance Matrix of a Symmetric Buried Body Using Group Theory

A major problem with the volume-current integral-equation technique of three-dimensional electromagnetic modeling is the computational time and-storage required to form and solve the impedance matrix equation for the scattering currents. If the horizontal cross sections of a body with vertical sides all possess a certain symmetry, the matrix contains information about the effect of the symmetry on the scattering currents. This information can be deduced easily using group representation theory independent of any numerical computation or particular incident field geometry, and the original matrix, containing redundant informnation, can be replaced by a block-diagonal matrix. A straightforward example is used to illustrate this general technique. The computer storage requirements and solution time for the block-diagonalized matrix equation are significantly smaller than those for the original matrix equation.     

Oxyluminescence of fatty natural substances

A number of fatty substances, covering a range from low to high degree of unsaturation, have been observed to emit light when heated. Relative intensities of light emitted at 200C are compared to degree of unsaturation. Activation energies were calculated for those samples giving approximately straight line plots of logG vs. 1/T, whereG is galvanometer deflection andT is the absolute temperature.     

Fabrication of single-walled carbon-nanotube-based pressure sensors

We report on the fabrication and characterization of bulk micromachined pressure sensors based on individual single-walled carbon nanotubes (SWNTs) as the active electromechanical transducer elements. The electromechanical sensor device consists of an individual electrically connected SWNT adsorbed on top of a 100-nm-thick atomic layer deposited (ALD) circular alumina (Al(2)O(3)) membrane with a radius in the range of 50-100 microm. A white light interferometer (WLI) was used to measure the deflection of the membrane due to differential pressure, and the mechanical properties of the device were characterized by bulge testing. Finally, we performed the first electromechanical measurements on strained metallic SWNTs adhering to a membrane and found a piezoresistive gauge factor of approximately 210 for metallic SWNTs.