39 research outputs found
A power generation study based on operating parameters of the linear engine using a power pack
Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.In this paper, we present our experimental research on a power pack based on the linear engine operating conditions and the linear generator structure for generating electric power. The power pack used in the study consisted of a two-stroke freepiston linear engine, linear generators, and air compressors. Each parameter of input caloric value, equivalence ratio, spark timing delay, electrical resistance, and air gap length were settled for identifying the combustion characteristics and for examining the linear engine performance. The linear engine was fueled with propane, and in the course of all its operations, intake air was fed under the wide open throttle condition. The air and fuel mass flow rate were varied by a mass flow controller and premixed by a pre-mixing device. The premixed gas was then directly supplied into each combustion cylinder. The experiments confirmed that power generation was induced differently for each respective operating condition. For the linear engine, piston frequency, velocity, and combustion characteristics were ultimately different for each operating condition. As a result, the piston frequency was 57.2Hz and the maximum generating power was 111.3W, where the operating conditions were as follows: 1.0 of equivalence ratio, 1.5ms of spark timing delay, 30Ω of electric resistance, and 1.0mm of air gap length.cf201
Pharmacologic intervention for prevention of fractures in osteopenic and osteoporotic postmenopausal women: Systemic review and meta-analysis
Objectives
Emerging evidence has indicated a role for pharmacologic agents in the primary prevention of osteoporotic fracture, but have not yet been systematically reviewed for meta-analysis. We conducted a meta-analysis to evaluate the efficacy of pharmacologic interventions in reducing fracture risk and increasing bone mineral density (BMD) in postmenopausal women with osteopenia or osteoporosis but without prevalent fragility fracture.
Method
The Medline, EMBASE, and CENTRAL databases were searched from inception to September 30, 2019. Only randomized placebo-controlled trials evaluating postmenopausal women with â1.0 > bone mineral density (BMD) T-score > â2.5 (low bone mass) and those with BMD T-score †â2.5 (osteoporosis) but without baseline fractures, who were receiving anti-osteoporotic agents, providing quantitative outcomes data and evaluating risk of vertebral and/or non-vertebral fragility fracture at follow-up. The PRISMA guidelines were followed, applying a random-effects model. The primary endpoint was the effect of anti-osteoporotic regimens in reducing the incidence of vertebral fractures. Secondary endpoints were percentage changes in baseline BMD at the lumbar spine and total hip at 1 and 2 years follow up.
Results
Full-text review of 144 articles yielded, 20 for meta-analysis. Bisphosphonates reduced the risk of vertebral fracture (pooled OR = 0.50, 95%CIs = 0.36â0.71) and significantly increased lumbar spine BMD after 1 year, by 4.42% vs placebo (95%CIs = 3.70%â5.14%). At the hip, this value was 2.94% (95%CIs = 2.13%â3.75%). Overall results of limited studies for non-bisphosphonate drugs showed increased BMD and raloxifene significantly decreases the risk of subsequent clinical vertebral fractures.
Conclusion
The bisphosphonates are efficacious and most evident for the primary prevention of osteoporotic vertebral fractures, reducing their incidence and improving BMD in postmenopausal women with osteopenia or osteoporosis
Characteristics of the Moveable Middle: Opportunities Among Adults Open to COVID-19 Vaccination
Introduction: Focusing on subpopulations that express the intention to receive a COVID-19 vaccination but are unvaccinated may improve the yield of COVID-19 vaccination efforts. Methods: A nationally representative sample of 789,658 U.S. adults aged â„18 years participated in the National Immunization Survey Adult COVID Module from May 2021 to April 2022. The survey assessed respondentsâ COVID-19 vaccination status and intent by demographic characteristics (age, urbanicity, educational attainment, region, insurance, income, and race/ethnicity). This study compared composition and within-group estimates of those who responded that they definitely or probably will get vaccinated or are unsure (moveable middle) from the first and last month of data collection. Results: Because vaccination uptake increased over the study period, the moveable middle declined among persons aged â„18 years. Adults aged 18â39 years and suburban residents comprised most of the moveable middle in April 2022. Groups with the largest moveable middles in April 2022 included persons with no insurance (10%), those aged 18â29 years (8%), and those with incomes below poverty (8%), followed by non-Hispanic Native Hawaiian or other Pacific Islander (7%), non-Hispanic multiple or other race (6%), non-Hispanic American Indian or Alaska Native persons (6%), non-Hispanic Black or African American persons (6%), those with below high school education (6%), those with high school education (5%), and those aged 30â39 years (5%). Conclusions: A sizable percentage of adults open to receiving COVID-19 vaccination remain in several demographic groups. Emphasizing engagement of persons who are unvaccinated in some racial/ethnic groups, aged 18â39 years, without health insurance, or with lower income may reach more persons open to vaccination
Novel Loci for Adiponectin Levels and Their Influence on Type 2 Diabetes and Metabolic Traits : A Multi-Ethnic Meta-Analysis of 45,891 Individuals
J. Kaprio, S. Ripatti ja M.-L. Lokki työryhmien jÀseniÀ.Peer reviewe