Three-Bladed Propeller Design for the Reduction of General Aviation Radiated Noise Characteristics

The purpose of this study was to design a quiet 3-Bladed propeller for general aviation aircraft. A combination of design technique and analytical predictions using the NASA Aircraft Noise Prediction Program - Propeller Analysis System (ANOPP-PAS) was used to achieve this goal. The propellers were designed for an engine power of 200 hp, a rotational speed of 2,400 RPM and a free-stream speed of 160 kts. A straight 76 in. diameter 2-bladed propeller was designed as a reference for the 64 in. diameter 3-bladed propeller. The ANOPP-PAS computer code was used for predicting the aerodynamic performance and radiated noise characteristics for both the 2-bladed and 3-bladed propeller designs. Through blade design modifications and the use of conventional, as well as specifically designed natural-laminar-flow (NLF) airfoils, 3-bladed propeller designs resulted in predicted noise reductions of 3.4 dB in the near-field which corresponds to 5.1 dBA; and a 3.4 dB (7.0 dBA) in the far-field when compared to the 2-bladed propeller. These 3-bladed designs resulted in no appreciable change in aerodynamic performance but an estimated 43% weight increase

Use of DES Modeling for Determining Launch Availability for SLS

The National Aeronautics and Space Administration (NASA) is developing new capabilities for human and scientific exploration beyond Earth's orbit. This effort includes the Space Shuttle derived Space Launch System (SLS), the Orion Multi-Purpose Crew Vehicle (MPCV), and the Ground Systems Development and Operations (GSDO). There are several requirements and Technical Performance Measures (TPMs) that have been levied by the Exploration Systems Development (ESD) upon the SLS, Orion, and GSDO Programs including an integrated Launch Availability (LA) TPM. The LA TPM is used to drive into the SLS, Orion and GSDO designs a high confidence of successfully launching exploration missions that have narrow Earth departure windows. The LA TPM takes into consideration the reliability of the overall system (SLS, Orion and GSDO), natural environments, likelihood of a failure, and the time required to recover from an anomaly. A challenge with the LA TPM is the interrelationships between SLS, Orion, GSDO and the natural environments during launch countdown and launch delays that makes it impossible to develop an analytical solution for calculating the integrated launch probability. This paper provides an overview of how Discrete Event Simulation (DES) modeling was used to develop the LA TPM, how it was allocated down to the individual programs, and how the LA analysis is being used to inform and drive the SLS, Orion, and GSDO designs to ensure adequate launch availability for future human exploration

Pharmacological insights into the role of P2X4 receptors in behavioural regulation: lessons from ivermectin

This is the publisher's version, also available electronically from http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8920271&fileId=S1461145712000909Purinergic ionotropic P2X receptors are a family of cation-permeable channels that bind extracellular adenosine 5′-triphosphate. In particular, convergent lines of evidence have recently highlighted P2X4 receptors as a potentially critical target in the regulation of multiple nervous and behavioural functions, including pain, neuroendocrine regulation and hippocampal plasticity. Nevertheless, the role of the P2X4 receptor in behavioural organization remains poorly investigated. To study the effects of P2X4 activation, we tested the acute effects of its potent positive allosteric modulator ivermectin (IVM, 2.5–10 mg/kg i.p.) on a broad set of paradigms capturing complementary aspects of perceptual, emotional and cognitive regulation in mice. In a novel open field, IVM did not induce significant changes in locomotor activity, but increased the time spent in the peripheral zone. In contrast, IVM produced anxiolytic-like effects in the elevated plus maze and marble burying tasks, as well as depression-like behaviours in the tail-suspension and forced swim tests. The agent induced no significant behavioural changes in the conditioned place preference test and in the novel object recognition task. Finally, the drug induced a dose-dependent decrease in sensorimotor gating, as assessed by pre-pulse inhibition (PPI) of the acoustic startle reflex. In P2X4 knockout mice, the effects of IVM in the open field and elevated plus maze were similar to those observed in wild type mice; conversely, the drug significantly increased startle amplitude and failed to reduce PPI. Taken together, these results suggest that P2X4 receptors may play a role in the regulation of sensorimotor gatin

Transarterial chemoembolization plus or minus intravenous bevacizumab in the treatment of hepatocellular cancer: A pilot study

<p>Abstract</p> <p>Background</p> <p>Stimulation of vascular endothelial growth factor (VEGF) has been observed following transarterial chemoembolization (TACE) in hepatocellular cancer (HCC) and may contribute to tumor regrowth. This pilot study examined whether intravenous (IV) bevacizumab, a monoclonal antibody against VEGF, could inhibit neovessel formation after TACE.</p> <p>Methods</p> <p>30 subjects with HCC undergoing TACE at a single academic institution were randomized with a computer-generated allocation in a one to one ratio to either bevacizumab at a dose of 10 mg/kg IV every 14 days beginning 1 week prior to TACE (TACE-BEV arm) or observation (TACE-O arm). Angiography was performed with TACE at day 8, and again at weeks 10 and 14. Repeat TACE was performed at week 14 if indicated. TACE-BEV subjects were allowed to continue bevacizumab beyond week 16. TACE-O subjects were allowed to cross-over to bevacizumab at week 16 in the setting of progressive disease. The main outcome measure was a comparison of neovessel formation by serial angiography. Secondary outcome measures were progression free survival (PFS) at 16 weeks, overall survival (OS), bevacizumab safety, and an analysis of VEGF levels before and after TACE with and without bevacizumab.</p> <p>Results</p> <p>Among the 30 subjects enrolled, 9 of 15 randomized to the TACE-O arm and 14 of 15 randomized to the TACE-BEV arm completed all 3 angiograms. At week 14, 3 of 9 (33%) TACE-O subjects and 2 of 14 (14%) TACE-BEV subjects demonstrated neovascularity. The PFS at 16 weeks was 0.19 in the TACE-O arm and 0.79 in the TACE-BEV arm (<it>p </it>= 0.021). The median OS was 61 months in the TACE-O arm and 49 months in the TACE-BEV arm (<it>p </it>= 0.21). No life-threatening bevacizumab-related toxicities were observed. There were no substantial differences in bevacizumab pharmacokinetics compared to historical controls. Bevacizumab attenuated the increase in VEGF observed post-TACE.</p> <p>Conclusions</p> <p>IV bevacizumab was well tolerated in selected HCC subjects undergoing TACE, and appeared to diminish neovessel formation at week 14.</p> <p>Trial registration</p> <p>ClinicalTrials.gov <a href="http://www.clinicaltrials.gov/ct2/show/NCT00049322">NCT00049322</a>.</p

Covid-19 and democracy, first cut policy analyses : country case studies

This report examines the intersection between political and policy responses to Covid-19 across 8 democracies (the UK, Germany, Romania, Bulgaria, Israel, Japan, Taiwan, and the US). In doing, it provides first-cut analyses of the early stages of the Covid-19 pandemic. For democracy to thrive, accountability is key. Core to this accountability is an understanding of how democratic states act to protect their citizens against a myriad of threats. In recent months, perhaps the largest of these threats has been the Covid-19 pandemic. Among the report's 8 case studies, some states were more prepared for such an event, and acted with more forethought, than others. This report shows that these differences in preparedness and forethought had real-world effects

Rationale and study protocol for the \u27Active Teen Leaders Avoiding Screen-time\u27 (ATLAS) group randomized controlled trial: An obesity prevention intervention for adolescent boys from schools in low-income communities

Introduction The negative consequences of unhealthy weight gain and the high likelihood of pediatric obesity tracking into adulthood highlight the importance of targeting youth who are \u27at risk\u27 of obesity. The aim of this paper is to report the rationale and study protocol for the \u27Active Teen Leaders Avoiding Screen-time\u27 (ATLAS) obesity prevention intervention for adolescent boys living in low-income communities. Methods/design The ATLAS intervention will be evaluated using a cluster randomized controlled trial in 14 secondary schools in the state of New South Wales (NSW), Australia (2012 to 2014). ATLAS is an 8-month multi-component, school-based program informed by self-determination theory and social cognitive theory. The intervention consists of teacher professional development, enhanced school-sport sessions, researcher-led seminars, lunch-time physical activity mentoring sessions, pedometers for self-monitoring, provision of equipment to schools, parental newsletters, and a smartphone application and website. Assessments were conducted at baseline and will be completed again at 9- and 18-months from baseline. Primary outcomes are body mass index (BMI) and waist circumference. Secondary outcomes include BMI z-scores, body fat (bioelectrical impedance analysis), physical activity (accelerometers), muscular fitness (grip strength and push-ups), screen-time, sugar-sweetened beverage consumption, resistance training skill competency, daytime sleepiness, subjective well-being, physical self-perception, pathological video gaming, and aggression. Hypothesized mediators of behavior change will also be explored. Discussion ATLAS is an innovative school-based intervention designed to improve the health behaviors and related outcomes of adolescent males in low-income communities

Use of DES Modeling for Determining Launch Availability for SLS

(1) NASA is developing a new heavy lift launch system for human and scientific exploration beyond Earth orbit comprising of the Space Launch System (SLS), Orion Multi-Purpose Crew Vehicle (MPCV), and Ground Systems Development and Operations (GSDO); (2) The desire of the system is to ensure a high confidence of successfully launching the exploration missions, especially those that require multiple launches, have a narrow Earth departure window, and high investment costs; and (3) This presentation discusses the process used by a Cross-Program team to develop the Exploration Systems Development (ESD) Launch Availability (LA) Technical Performance Measure (TPM) and allocate it to each of the Programs through the use of Discrete Event Simulations (DES)

Reconstitution of an epithelial chloride channel. Conservation of the channel from mudpuppy to man

We have previously shown that monoclonal antibody E12 (MAb E12), one of several such antibodies raised against theophylline-treated Necturus gallbladder (NGB) epithelial cells, inhibits the chloride conductance in the apical membrane of that tissue. Since chloride channels are critical to the secretory function of epithelia in many different animals, we have used this antibody to determine whether the channels are conserved, and in an immunoaffinity column to isolate the channel protein. We now demonstrate that MAb E12 cross-reacts with detergent- solubilized extracts of different tissues from various species by enzyme-linked immunosorbent assay (ELISA). Western blot analysis shows that this monoclonal antibody recognizes proteins of Mr 219,000 in NGB, toad gallbladder, urinary bladder, and small intestine, A6 cells, rat colon, rabbit gastric mucosa, human lymphocytes, and human nasal epithelial cells, and inhibits the chloride conductance in toad gallbladder, rat colon, and human nasal epithelium. Detergent- solubilized protein eluted from an immunoaffinity column and then further purified via FPLC yields a fraction (Mr 200,000-220,000) which has been reconstituted into a planar lipid bilayer. There it behaves as a chloride-selective channel (PCl/PNa = 20.2 in a 150/50 mM trans- bilayer NaCl gradient) whose unit conductance is 62.4 +/- 4.6 pS, and which is blocked in the bilayer by the antibody. The gating characteristics of this channel indicate that it can exist as aggregates or as independent single channels, and that the antibody interferes with gating of the aggregates, leaving the unit channels unchanged. From these data we conclude that the protein of Mr 219,000 recognized by this monoclonal antibody is an important component of an epithelial chloride channel, and that this channel is conserved across a wide range of animal species

Acute hospital admissions among nursing home residents: a population-based observational study

<p>Abstract</p> <p>Background</p> <p>Nursing home residents are prone to acute illness due to their high age, underlying illnesses and immobility. We examined the incidence of acute hospital admissions among nursing home residents versus the age-matched community dwelling population in a geographically defined area during a two years period. The hospital stays of the nursing home population are described according to diagnosis, length of stay and mortality. Similar studies have previously not been reported in Scandinavia.</p> <p>Methods</p> <p>The acute hospitalisations of the nursing home residents were identified through ambulance records. These were linked to hospital patient records for inclusion of demographics, diagnosis at discharge, length of stay and mortality. Incidence of hospitalisation was calculated based on patient-time at risk.</p> <p>Results</p> <p>The annual hospital admission incidence was 0.62 admissions per person-year among the nursing home residents and 0.26 among the community dwellers. In the nursing home population we found that dominant diagnoses were respiratory diseases, falls-related and circulatory diseases, accounting for 55% of the cases. The median length of stay was 3 days (interquartile range = 4). The in-hospital mortality rate was 16% and 30 day mortality after discharge 30%.</p> <p>Conclusion</p> <p>Acute hospital admission rate among nursing home residents was high in this Scandinavian setting. The pattern of diagnoses causing the admissions appears to be consistent with previous research. The in-hospital and 30 day mortality rates are high.</p