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R. Menéndez

Publications and source records attributed to R. Menéndez.

2 recordsLinked to original sources
PubMed2001

Monitoring unidirectional carbon/carbon composite processing by light microscopy.

Unidirectional carbon/carbon composites were prepared using polyacrylonitrile-based carbon fibres and a commercial coal-tar pitch. The preparation includes a three-sequential-step process: (i) prepreging, (ii) moulding/pressing, and (iii) carbonization to 1000 degrees C. The effect of the process parameters including pressure, mould characteristics, and temperature and duration of pressure application on the microstructure of composites was monitored by light microscopy. Results show that the application of a pressure of 1 MPa close to the temperature of pitch solidification produces lower porosity composites. This porosity is significantly reduced when the solidification of the pitch is tempered by the introduction of a soak time of 10 h at the temperature at which pressure is applied.

Journal Article↗
PubMed2001

Effects of D-002 on Lipid Peroxidation in Older Subjects.

D-002 is a mixture of higher aliphatic alcohols isolated from beeswax that inhibits rat microsomal lipid peroxidation in vitro and in vivo. This study was undertaken to investigate whether D-002 also inhibits lipid peroxidation in older subjects. The free radical theory of aging suggests that progressive defects in the protection against free radical reactions leads to progressive deleterious effects of free radicals on cells and tissues. This free radical damage has been implicated in several pathophysiological processes associated with the chronic degenerative diseases that occur with aging. Forty-eight older subjects were randomly assigned, in a double-blind fashion, to receive placebo or D-002 tablets (50 mg/day) once daily. At baseline, D-002 and placebo groups were well matched regarding several variables. D-002 significantly reduced the susceptibility of nonfractionated plasma samples to copper-mediated lipid peroxidation. It also significantly increased the length of the lag phase (P <.001) and the total antiioxidant status (P <.05) compared with baseline and placebo. In addition, D-002 significantly decreased malondialdehyde levels (expressed in terms of thiobarbituric acid reactive substances (TBARS, P <.001) compared with baseline, but not with placebo. No significant changes on lipid peroxidation parameters were observed in the placebo group. We conclude that D-002 treatment may be useful to prevent or manage certain pathophysiological conditions in the elderly.

Journal Article↗