X-ray Studies of Exoplanets: A 2020 Decadal Survey White Paper

Over the last two decades, the discovery of exoplanets has fundamentally changed our perception of the universe and humanity's place within it. Recent work indicates that a solar system's X-ray and high energy particle environment is of fundamental importance to the formation and development of the atmospheres of close-in planets such as hot Jupiters, and Earth-like planets around M stars. X-ray imaging and spectroscopy provide powerful and unique windows into the high energy flux that an exoplanet experiences, and X-ray photons also serve as proxies for potentially transfigurative coronal mass ejections. Finally, if the host star is a bright enough X-ray source, transit measurements akin to those in the optical and infrared are possible and allow for direct characterization of the upper atmospheres of exoplanets. In this brief white paper, we discuss contributions to the study of exoplanets and their environs which can be made by X-ray data of increasingly high quality that are achievable in the next 10--15 years

Cost-effectiveness of tuberculosis evaluation and treatment of newly-arrived immigrants

BACKGROUND: Immigrants to the U.S. are required to undergo overseas screening for tuberculosis (TB), but the value of evaluation and treatment following entry to the U.S. is not well understood. We determined the cost-effectiveness of domestic follow-up of immigrants identified as tuberculosis suspects through overseas screening. METHODS: Using a stochastic simulation for tuberculosis reactivation, transmission, and follow-up for a hypothetical cohort of 1000 individuals, we calculated the incremental cost-effectiveness of follow-up and evaluation interventions. We utilized published literature, California Reports of Verified Cases of Tuberculosis (RVCTs), demographic estimates from the California Department of Finance, Medicare reimbursement, and Medi-Cal reimbursement rates. Our target population was legal immigrants to the United States, our time horizon is twenty years, and our perspective was that of all domestic health-care payers. We examined the intervention to offer latent tuberculosis therapy to infected individuals, to increase the yield of domestic evaluation, and to increase the starting and completion rates of LTBI therapy with INH (isoniazid). Our outcome measures were the number of cases averted, the number of deaths averted, the incremental dollar cost (year 2004), and the number of quality-adjusted life-years saved. RESULTS: Domestic follow-up of B-notification patients, including LTBI treatment for latently infected individuals, is highly cost-effective, and at times, cost-saving. B-notification follow-up in California would reduce the number of new tuberculosis cases by about 6–26 per year (out of a total of approximately 3000). Sensitivity analysis revealed that domestic follow-up remains cost-effective when the hepatitis rates due to INH therapy are over fifteen times our best estimates, when at least 0.4 percent of patients have active disease and when hospitalization of cases detected through domestic follow-up is no less likely than hospitalization of passively detected cases. CONCLUSION: While the current immigration screening program is unlikely to result in a large change in case rates, domestic follow-up of B-notification patients, including LTBI treatment, is highly cost-effective. If as many as three percent of screened individuals have active TB, and early detection reduces the rate of hospitalization, net savings may be expected

Sensory Input Pathways and Mechanisms in Swallowing: A Review

Over the past 20 years, research on the physiology of swallowing has confirmed that the oropharyngeal swallowing process can be modulated, both volitionally and in response to different sensory stimuli. In this review we identify what is known regarding the sensory pathways and mechanisms that are now thought to influence swallowing motor control and evoke its response. By synthesizing the current state of research evidence and knowledge, we identify continuing gaps in our knowledge of these mechanisms and pose questions for future research

Gangliosides potentiate the immunosuppressive effects of cyclosporin A in rat skin allografts

In vitro gangliosides exert inhibitory effects on cellular immune responses, largely relying on an impairment of the IL-2/IL-2 receptor interaction. In a previous study we have demonstrated synergistic effects of gangliosides and cyclosporin A (CyA) in the inhibition of the generation of in vitro allospecific immune responses in humans. To evaluate the possibility of using these drugs in immunosuppressive therapy in organ transplantation, we investigated the effects of the combination of a gangliosides mixture (GAMIX) and suboptimal doses of CyA on rat skin allografts in vivo. Sprague-Dawley rats were implanted with skin grafts from Lewis rats and treated for 21 days by intraperitoneal administration of either GAMIX or CyA or a combination of the two drugs. Untreated, GAMIX-treated or CyA-treated rats rejected skin allografts. In contrast, when a combined GAMIX CyA treatment was administered, successful grafting could be obtained in 8 rats out of 10 tested. Cells derived from spleens on day 21 post graft were stimulated in vitro with PWM mitogen. We found that cells from transplanted rats, untreated or treated with low-dose CyA or GAMIX alone, showed comparable responses to PWM. Cells from rats treated with the combination of the two drugs were found to be virtually unresponsive to stimulation by PWM mitogen. Taken together, our results indicate that GAMIX potentiate in vivo and ex vivo immunosuppressive effects of low-dose CyA