Guillermo Acosta - Academia.edu (original) (raw)

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Papers by Guillermo Acosta

Research paper thumbnail of Molecular Mechanisms of Endothelial Dysfunction: From Nitric Oxide Synthesis to ADMA Inhibition

American Journal of Therapeutics, 2008

Endothelial dysfunction symbolizes several pathological conditions, including altered anticoagula... more Endothelial dysfunction symbolizes several pathological conditions, including altered anticoagulant and anti-inflammatory properties of the endothelium, impaired modulation of vascular growth, and dysregulation of vascular remodeling. Nevertheless, this term has been used commonly to refer to an impairment of endothelium-dependent vasorelaxation caused by a loss of nitric oxide bioactivity. The clinical and scientific relevance of nitric oxide synthesis and bioavailability in endothelial dysfunction is based on the fact that it is a common factor in the pathogenesis of cardiovascular diseases. These alterations have been demonstrated in both animal models and humans, in the scope of dangerous pathological conditions such as cigarette smoking, hypertension, hypercholesterolemia, aging, diabetes, and heart failure. A decline in nitric oxide bioavailability may be caused by decreased expression of the endothelial nitric oxide synthase, a reduction of substrate or cofactors for this enzyme, alterations of cellular signaling, enzyme inhibition by asymmetric dimethyl arginine, and, finally, accelerated nitric oxide degradation by reactive oxygen species. The knowledge of the processes related to these alterations becomes of remarkable importance for understanding the generation of innovative and effective therapeutic strategies for cardiovascular diseases.

Research paper thumbnail of Model Development for the Wideband Vehicle-to-vehicle 2.4 GHz Channel

Statistical channel models are presented for a frequency selective vehicle-to-vehicle or mobile-t... more Statistical channel models are presented for a frequency selective vehicle-to-vehicle or mobile-to-mobile wireless communications link in an expressway environment in Atlanta, Georgia, where both vehicles travel in the same direction. The models were developed from measurements taken using the direct sequence spread spectrum (DSSS) technique at 2.45 GHz. The models imply a non-separable channel with a persistent Rician behavior across multiple model taps.

Research paper thumbnail of Model development for the wideband expressway vehicle-to-vehicle 2.4 GHz channel

Statistical channel models for small-scale fading are presented for a frequency selective vehicle... more Statistical channel models for small-scale fading are presented for a frequency selective vehicle-to-vehicle or mobile-to-mobile wireless communications link in an expressway environment in Atlanta, Georgia, where both vehicles travel in the same direction. These doubly selective models were developed from measurements taken using the direct sequence spread spectrum (DSSS) technique at 2.45 GHz. The models imply a non-separable channel with a persistent Ricean behavior across multiple model taps. We also explore model dynamics by comparing BER statistics for an overall model that is fit to the entire data set with those of a collection of models, each fit to smaller, non-overlapping intervals

Research paper thumbnail of Measured joint Doppler-delay power profiles for vehicle-to-vehicle communications at 2.4 GHz

Measured per-tap Doppler spectra are presented for a frequency selective vehicle-to-vehicle or mo... more Measured per-tap Doppler spectra are presented for a frequency selective vehicle-to-vehicle or mobile-to-mobile wireless communications link in various multipath environments in Atlanta, Georgia. The measurements were taken using the direct sequence spread spectrum (DSSS) technique at 2.45 GHz. The environments, chosen for their exceptionally long delay spreads, include an expressway, an urban T-intersection, and an exit ramp. The different environments produced quite different spectra. Also, for a given channel, the spectra corresponding to different delays were different, implying a non-separable channel model.

Research paper thumbnail of Molecular Mechanisms of Endothelial Dysfunction: From Nitric Oxide Synthesis to ADMA Inhibition

American Journal of Therapeutics, 2008

Endothelial dysfunction symbolizes several pathological conditions, including altered anticoagula... more Endothelial dysfunction symbolizes several pathological conditions, including altered anticoagulant and anti-inflammatory properties of the endothelium, impaired modulation of vascular growth, and dysregulation of vascular remodeling. Nevertheless, this term has been used commonly to refer to an impairment of endothelium-dependent vasorelaxation caused by a loss of nitric oxide bioactivity. The clinical and scientific relevance of nitric oxide synthesis and bioavailability in endothelial dysfunction is based on the fact that it is a common factor in the pathogenesis of cardiovascular diseases. These alterations have been demonstrated in both animal models and humans, in the scope of dangerous pathological conditions such as cigarette smoking, hypertension, hypercholesterolemia, aging, diabetes, and heart failure. A decline in nitric oxide bioavailability may be caused by decreased expression of the endothelial nitric oxide synthase, a reduction of substrate or cofactors for this enzyme, alterations of cellular signaling, enzyme inhibition by asymmetric dimethyl arginine, and, finally, accelerated nitric oxide degradation by reactive oxygen species. The knowledge of the processes related to these alterations becomes of remarkable importance for understanding the generation of innovative and effective therapeutic strategies for cardiovascular diseases.

Research paper thumbnail of Model Development for the Wideband Vehicle-to-vehicle 2.4 GHz Channel

Statistical channel models are presented for a frequency selective vehicle-to-vehicle or mobile-t... more Statistical channel models are presented for a frequency selective vehicle-to-vehicle or mobile-to-mobile wireless communications link in an expressway environment in Atlanta, Georgia, where both vehicles travel in the same direction. The models were developed from measurements taken using the direct sequence spread spectrum (DSSS) technique at 2.45 GHz. The models imply a non-separable channel with a persistent Rician behavior across multiple model taps.

Research paper thumbnail of Model development for the wideband expressway vehicle-to-vehicle 2.4 GHz channel

Statistical channel models for small-scale fading are presented for a frequency selective vehicle... more Statistical channel models for small-scale fading are presented for a frequency selective vehicle-to-vehicle or mobile-to-mobile wireless communications link in an expressway environment in Atlanta, Georgia, where both vehicles travel in the same direction. These doubly selective models were developed from measurements taken using the direct sequence spread spectrum (DSSS) technique at 2.45 GHz. The models imply a non-separable channel with a persistent Ricean behavior across multiple model taps. We also explore model dynamics by comparing BER statistics for an overall model that is fit to the entire data set with those of a collection of models, each fit to smaller, non-overlapping intervals

Research paper thumbnail of Measured joint Doppler-delay power profiles for vehicle-to-vehicle communications at 2.4 GHz

Measured per-tap Doppler spectra are presented for a frequency selective vehicle-to-vehicle or mo... more Measured per-tap Doppler spectra are presented for a frequency selective vehicle-to-vehicle or mobile-to-mobile wireless communications link in various multipath environments in Atlanta, Georgia. The measurements were taken using the direct sequence spread spectrum (DSSS) technique at 2.45 GHz. The environments, chosen for their exceptionally long delay spreads, include an expressway, an urban T-intersection, and an exit ramp. The different environments produced quite different spectra. Also, for a given channel, the spectra corresponding to different delays were different, implying a non-separable channel model.