Cardiac rehabilitation: a comprehensive review

Cardiac rehabilitation (CR) is a commonly used treatment for men and women with cardiovascular disease. To date, no single study has conclusively demonstrated a comprehensive benefit of CR. Numerous individual studies, however, have demonstrated beneficial effects such as improved risk-factor profile, slower disease progression, decreased morbidity, and decreased mortality. This paper will review the evidence for the use of CR and discuss the implications and limitations of these studies. The safety, relevance to special populations, challenges, and future directions of CR will also be reviewed

High single-mode power conversion efficiency vertical-cavity top-surface-emitting lasers

Includes bibliographical references.We report advances in the power conversion (wall-plug) efficiency of vertical-cavity top-surface-emitting lasers. The devices were fabricated from molecular beam epitaxial layers using deep proton implants to define gain-guided lasers. The epitaxial structure included low resistance, piecewise linearly graded n-type and p-type mirrors, a triple In0.2Ga0.8As quantum-well active region, and a delta-doped contact layer. Power conversion efficiencies as high as 12.7% for continuous-wave single-mode operation were measured after several hours of device operation.This work was supported by the U.S. Department of Energy under Contract DE-AC04-76DP00789

Habitat-Based Intraguild Predation By Caribbean Reef Octopus Octopus Briareus on Juvenile Caribbean Spiny Lobster Panulirus Argus

Intraguild predation occurs when species simultaneously compete for resources and interact as predator and prey, which describes the interaction between juvenile Caribbean spiny lobster Panulirus argus and Caribbean reef octopus Octopus briareus in the Florida Keys, USA. Octopuses are notorious predators of decapod crustaceans, and their use of crevice shelters suggests that they may also compete for shelter with their lobster prey. Lobsters use mainly chemical cues to detect and avoid octopus, so we hypothesized that the negative association between these species may be as much the consequence of avoidance of a superior competitor as it is of direct predation. Surveys of lobsters and octopuses occupying artificial shelters at 19 hard-bottom sites confirmed that lobsters do not share dens with octopuses, and also show that lobster and octopus abundances are negatively correlated. Tethering experiments on a subset of those sites revealed that predation on lobster was indeed higher on sites with more octopuses. Results from mesocosm studies indicated that although juvenile lobsters do not attain a size refuge from octopus predation, the presence of alternative prey and lobster conspecifics reduces the risk of predation on lobster by octopus. Mesocosm experiments also showed that octopuses were the competitive dominants when shelter was limited. Thus, the negative association between lobster and octopus in the field appears to be driven by both predation and avoidance of octopus-rich sites by lobsters, rather than competition per se. However, crevice shelters suitable for juvenile lobster are limited in many hard-bottom areas in the Florida Keys, so areas where octopuses are abundant may further limit the local accessibility of shelters for juvenile spiny lobsters even if the direct effects of predation by octopus are minimal

Quantum Decoherence in a D-Foam Background

Within the general framework of Liouville string theory, we construct a model for quantum D-brane fluctuations in the space-time background through which light closed-string states propagate. The model is based on monopole and vortex defects on the world sheet, which have been discussed previously in a treatment of 1+1-dimensional black-hole fluctuations in the space-time background, and makes use of a T-duality transformation to relate formulations with Neumann and Dirichlet boundary conditions. In accordance with previous general arguments, we derive an open quantum-mechanical description of this D-brane foam which embodies momentum and energy conservation and small mean energy fluctuations. Quantum decoherence effects appear at a rate consistent with previous estimates.Comment: 16 pages, Latex, two eps figures include

Comparative analysis of vertebrate EIF2AK2 (PKR) genes and assignment of the equine gene to ECA15q24-q25 and the bovine gene to BTA11q12-q15

The structures of the canine, rabbit, bovine and equine EIF2AK2 genes were determined. Each of these genes has a 5\u27 non-coding exon as well as 15 coding exons. All of the canine, bovine and equine EIF2AK2 introns have consensus donor and acceptor splice sites. In the equine EIF2AK2 gene, a unique single nucleotide polymorphism that encoded a Tyr329Cys substitution was detected. Regulatory elements predicted in the promoter region were conserved in ungulates, primates, rodents, Afrotheria (elephant) and Insectifora (shrew). Western clawed frog and fugu EIF2AK2 gene sequences were detected in the USCS Genome Browser and compared to those of other vertebrate EIF2AK2 genes. A comparison of EIF2AK2 protein domains in vertebrates indicates that the kinase catalytic domains were evolutionarily more conserved than the nucleic acid-binding motifs. Nucleotide substitution rates were uniform among the vertebrate sequences with the exception of the zebrafish and goldfish EIF2AK2 genes, which showed substitution rates about 20% higher than those of other vertebrates. FISH was used to physically assign the horse and cattle genes to chromosome locations, ECA15q24-q25 and BTA11q12-15, respectively. Comparative mapping data confirmed conservation of synteny between ungulates, humans and rodents

Predictors of Metabolic Syndrome in Participants of a Cardiac Rehabilitation Program

Metabolic syndrome increases the risk of all-cause mortality, cardiovascular mortality and cardiovascular events in patients with cardiovascular disease (CVD). This study assessed the predictors of metabolic syndrome, both its incidence and resolution in a cohort of cardiac rehabilitation program graduates. Methods. A total of 154 and 80 participants without and with metabolic syndrome respectively were followed for 48 months. Anthropometric measurements, metabolic risk factors, and quality of life were assessed at baseline and at 48 months. Logistic regression models were used to assess the predictors of metabolic syndrome onset and resolution. Results. Increasing waist circumference (OR 1.175, P ≤ 0.001) was an independent predictor for incident metabolic syndrome (R2 for model = 0.46). Increasing waist circumference (OR 1.234, P ≤ 0.001), decreasing HDL-C (OR 0.027, P = 0.005), and increasing triglycerides (OR 3.005, P = 0.003) were predictors of metabolic syndrome resolution. Conclusion. Patients with CVD that further develop metabolic syndrome are particularly susceptible for the cascade of cardiovascular events and mortality. Increasing waist circumference confers a higher risk for future onset of metabolic syndrome in this group of patients. They will require closer follow-up and should be targeted for further prevention strategies after cardiac rehabilitation program completion

Internet-Based Support for Cardiovascular Disease Management

With significant declines in cardiovascular disease (CVD) mortality, attention has shifted to patient management. Programs designed to manage CVD require the involvement of health professionals for comanagement and patients' self-management. However, these programs are commonly limited to large urban centers, resulting in limited access for rural patients. The use of telehealth potentially overcomes geographical barriers and can improve access to care for patients. The current research explores how an Internet-based platform might facilitate collaboration among healthcare providers comanaging patients and enhance behavioural change in patients. Forty-eight participants were interviewed including: (a) patients (n = 12), (b) physicians (n = 11), (c) nurses (n = 13), and (d) allied health professionals (n = 10). The results were organized and analyzed in three central themes: (1) role of technology for CVD management, (2) challenges to technology adoption, and (3) incentives for technology adoption. Health care providers and patients supported future implementation of Internet-based technology support for CVD management