27 research outputs found
NUMERICAL SIMULATION OF NOZZLE FLOW WITH CHEMICAL EQUILIBRIUM
ABSTRACT The compressible two-dimensional planar and axisymmetric Navier-Stokes equations are solved in generalized curvilinear coordinates to simulate non-reacting and chemical equilibrium nozzle flows. A zonal turbulence model of ω − k is used in the simulations to compute the eddy viscosity. A numerical method is developed to discretize the governing equations using the finite difference technique. The convective terms in the governing equations are solved numerically using a second order flux difference splitting method of Roe while a second order central difference is used for the viscous terms. The discretized equations are integrated implicitly in time to increase the stability of the numerical scheme. The flow solver is coupled with a chemical equilibrium module to compute the composition of gas mixture of known enthalpy and pressure. Few test cases are performed to illustrate the capabilities of the flow solver to predict nozzle flow with and without chemical equilibrium. The results are compared with the published data and the results are in good agreement with those published simulations of the same test cases
The effects of digital health interventions for pulmonary rehabilitation in people with COPD: a systematic review of randomized controlled trials
Background and Objectives: Chronic Obstructive Pulmonary Disease (COPD) is the third most common cause of death globally. Pulmonary rehabilitation (PR) programmes are important to reduce COPD symptoms and improve the quality of life of people with COPD. Digital health interventions have recently been adopted in PR programmes, which allow people with COPD to participate in such programmes with low barriers. The aim of this study is to review and discuss the reported effects of digital health interventions on PR outcomes in people with COPD. Materials and Methods: To achieve the study goals, a systematic literature search was conducted using PubMed (MEDLINE), CINAHL, AMED, SPORTDiscus and the Physiotherapy Evidence Database. Randomised clinical trials (RCTs) were included if they met specified criteria. Two reviewers independently checked titles, abstracts, and performed full-text screening and data extraction. The quality assessment and risk of bias were performed in accordance with the PEDRO scale and Cochrane Risk of Bias tool 2, respectively. Results: Thirteen RCTs were included in this systematic review with 1525 participants with COPD. This systematic review showed the potential positive effect of digital health PR on the exercise capacity—measured by 6- and 12-min walking tests, pulmonary function, dyspnoea and health-related quality of life. There was no evidence for advantages of digital health PR in the improvement of anxiety, depression, and self-efficacy. Conclusions: Digital health PR is more effective than traditional PR in improving the pulmonary and physical outcomes for people with COPD, but there was no difference between the two PR programmes in improving the psychosocial outcomes. The certainty of the findings of this review is affected by the small number of included studies
Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease
BACKGROUND:
Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes.
METHODS:
We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization.
RESULTS:
During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events.
CONCLUSIONS:
Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)
Design Optimization of a Transonic-Fan Rotor Using Numerical Computations of the Full Compressible Navier-Stokes Equations and Simplex Algorithm
The design of a transonic-fan rotor is optimized using numerical computations of the full three-dimensional Navier-Stokes equations. The CFDRC-ACE multiphysics module, which is a pressure-based solver, is used for the numerical simulation. The code is coupled with simplex optimization algorithm. The optimization process is started from a suitable design point obtained using low fidelity analytical methods that is based on experimental correlations for the pressure losses and blade deviation angle. The fan blade shape is defined by its stacking line and airfoil shape which are considered the optimization parameters. The stacking line is defined by lean, sweep, and skews, while blade airfoil shape is modified considering the thickness and camber distributions. The optimization has been performed to maximize the rotor total pressure ratio while keeping the rotor efficiency and surge margin above certain required values. The results obtained are verified with the experimental data of Rotor 67. In addition, the results of the optimized fan indicate that the optimum design is found to be leaned in the direction of rotation and has a forward sweep from the hub to mean section and backward sweep to the tip. The pressure ratio increases from 1.427 to 1.627 at the design speed and mass flow rate
The fatty acid-rich fraction of Eruca sativa (rocket salad) leaf extract exerts antidiabetic effects in cultured skeletal muscle, adipocytes and liver cells
Context: Eruca sativa Mill. (Brassicaceae), commonly known as rocket salad, is a popular leafy-green vegetable with many health benefits. Objective: To evaluate the antidiabetic activities of this plant in major insulin-responsive tissues. Materials and methods: Five E. sativa leaf extracts of varying polarity were prepared (aqueous extract, 70% and 95% ethanol extracts, the n-hexane-soluble fraction of the 95% ethanol extract (ES3) and the defatted 95% ethanol extract). Eruca sativa extracts were investigated through a variety of cell-based in vitro bioassays for antidiabetic activities in C2C12 skeletal muscle cells, H4IIE hepatocytes and 3T3-L1 adipocytes. Guided by the results of these bioassays, ES3 was fractionated into the saponifiable (SM) and the unspaonifiable (USM) fractions. Glucose uptake was measured using [3H]-deoxy-glucose, while the effects on hepatic glucose-6-phosphatase (G6Pase) and adipogenesis were assessed using Wako AutoKit Glucose and AdipoRed assays, respectively. Results: ES3 and its SM fraction significantly stimulated glucose uptake with EC50 values of 8.0 and 5.8 μg/mL, respectively. Both extracts significantly inhibited G6Pase activity (IC50 values of 4.8 and 9.3 μg/mL, respectively). Moreover, ES3 and SM showed significant adipogenic activities with EC50 of 4.3 and 6.1 μg/mL, respectively. Fatty acid content of SM was identified by GC-MS. trans-Vaccenic and palmitoleic acids were the major unsaturated fatty acids, while palmitic and azelaic acids were the main saturated fatty acids. Discussion and conclusion: These findings indicate that ES3 and its fatty acid-rich fraction exhibit antidiabetic activities in insulin-responsive cell lines and may hence prove useful for the treatment of type 2 diabetes
Metabolomic profiling and cytotoxic tetrahydrofurofuran lignans investigations from Premna odorata Blanco
Metabolomic profiling of different Premna odorata Blanco (Lamiaceae) organs, bark, wood, young stems, flowers, and fruits dereplicated 20, 20, 10, 20, and 20 compounds, respectively, using LC–HRESIMS. The identified metabolites (1–34) belonged to different chemical classes, including iridoids, flavones, phenyl ethanoids, and lignans. A phytochemical investigation of P. odorata bark afforded one new tetrahydrofurofuran lignan, 4β-hydroxyasarinin 35, along with fourteen known compounds. The structure of the new compound was confirmed using extensive 1D and 2D NMR, and HRESIMS analyses. A cytotoxic investigation of compounds 35–38 against the HL-60, HT-29, and MCF-7 cancer cell lines, using the MTT assay showed that compound 35 had cytotoxic effects against HL-60 and MCF-7 with IC50 values of 2.7 and 4.2 µg/mL, respectively. A pharmacophore map of compounds 35 showed two hydrogen bond acceptor (HBA) aligning the phenoxy oxygen atoms of benzodioxole moieties, two aromatic ring features vectored on the two phenyl rings, one hydrogen bond donor (HBD) feature aligning the central hydroxyl group and thirteen exclusion spheres which limit the boundaries of sterically inaccessible regions of the target’s active site