STUDY OF MACROTURBULENCE AND BURSTING VIA THE -1 SPECTRAL POWER LAW REGION OF TURBULENT OPEN CHANNEL FLOWS OVER GRAVEL BEDS

The large scale and smaller production scale motions contain over the half of turbulent kinetic energy in the flow. These motions are responsible for sediment transport and deposition processes, contaminant mixing and stream bio-diversity. These motions are corresponded to the left and right bounds of -1 power region of the spectral energy. The most well recognized and highly studied power law has been upon Kolmogorov’s -5/3 power law region of the streamwise spectral energy density and this research focused on investigating the -1 power region bounds and energy. Energy budget and time-average turbulence calculations along with spectral analysis are performed to investigate the characteristics of large scale and smaller production scale motions in the flow. Spectral analyses of turbulent flows offers the utility of investigating the distribution of turbulent energy across wavenumber scales as well as identifying prominent wavenumbers at which the periodicity of coherent processes are centered. In turn, the results of spectral analyses can be coupled with visualization of coherent vortices and time-average turbulence results to advance our understanding of turbulent energy distribution and dominant processes that drive environmental phenomena such as sediment transport and solute transfer. A new method for identifying the wavenumbers associated to the macroturbulence and bursting is introduced. Also this study offers a new scaling method of energy spectral that derived from the turbulence energy model for an equilibrium boundary layer. Results of this study show an equilibrium boundary layer for the outer region of the flow in which the flow is uniform and fully-developed. Also for a given roughness, the results of this study provide an approach to calculate the streamwise turbulence kinetic energy of bursting and macroturbulence which show a linkage of this work to applications such as bedload and suspended load sediment transport

The potential therapeutic use of renin-angiotensin system inhibitors in the treatment of inflammatory diseases

Inflammation is a normal part of the immune response to injury or infection but its dysregulation promotes the development of inflammatory diseases, which cause considerable human suffering. Non-steroidal anti-inflammatory agents (NSAIDs) are the most commonly prescribed agents for the treatment of inflammatory diseases but they are accompanied by a broad range of side effects, including gastrointestinal and cardiovascular events. The renin-angiotensin system (RAS) is traditionally known for its role in blood pressure regulation. However, there is increasing evidence that RAS signalling is also involved in the inflammatory response associated with several disease states. Angiotensin II increases blood pressure by binding to angiotensin type 1 (AT1) receptor, and direct renin inhibitors (DRIs), angiotensin-converting enzyme (ACE) inhibitors and AT1 receptor blockers (ARBs) are clinically used as anti-hypertensive agents. Recent data suggest that these drugs also have anti-inflammatory effects. Therefore, this review summarizes these recent findings for the efficacy of two of the most widely used antihypertensive drug classes, ACE inhibitors and ARBs, to reduce or treat inflammatory diseases such as atherosclerosis, arthritis, steatohepatitis, colitis, pancreatitis and nephritis

Effect of water storage on ultimate tensile strength and mass changes of universal adhesives

The aim of the present study was to evaluate the influence of water storage on micro tensile strength (µTS) and mass changes (MC) of two universal adhesives. 10 disk-shaped specimens were prepared for each adhesive; Scotchbond Universal (SCU) All-Bond Universal (ABU) and Adper Single Bond 2 (SB2). At the baseline and after 1 day and 28 days of water storage, their mass were measured and compared to estimate water sorption and solubility. For µTS test, 20 dumbbell shaped specimens were also prepared for each adhesive in two subgroups of 1 day and 28 days water storage. MC was significantly lower for SCU and ABU than SB2 (P < 0.05) at both time intervals. In all three adhesives, the MC was significantly lower at 28 days compared to that at 1 day (P < 0.05). Similarly, µTS was significantly higher for SCU and ABU than SB2 at both storage intervals (P < 0.05). After 28 days, µTS increased significantly for universal adhesives (P < 0.05). MC and µTS of adhesives were both material and time dependent when stored in water; both universal adhesives showed less water sorption and higher values of µTS than the control group

Evaluation of Cytotoxicity Effects of Combination Nano-Curcumin and Berberine in Breast Cancer Cell Line

Background: Berberine and Nano-curcumin are two herbal medicines with strong anti-cancer effects on tumor cells, but low toxicity on normal cells, when used alone. Breast cancer is known as the most common cancer in women and second deadly one. In this study, we evaluated the cytotoxicity effects of combination Berberine and Nano-curcumin in breast cancer cell line to see whether they have further synergism cytotoxicity on MCF-7 breast cancer cell line. Methods: The cytotoxicity effects of Berberine and Nano-curcumin alone and in combination, were evaluated in MCF-7 cell lines using MTT cytotoxicity test. Statistical analysis is done through one-way ANOVA and Tukey multiple range tests. Results: Analyzing results of this study showed that cytotoxicity of Nano-curcumin was higher than Berberine in a dose-dependent manner. The IC50 of combination Berberine and Nano-curcumin was lower and showed higher cytotoxicity in MCF-7 cells compared with the time we use each of these drugs alone. Conclusion: In this study co-treatment of Berberine and Nano-curcumin significantly inhibited the growth of MCF-7 breast cancer cell line and resulted in synergism cytotoxicity effects. These results indicated on their potency to further combination of these two drugs with other agents and common chemotherapies to improve breast cancer outcomes

A Study Of Particle Entrainment In Two Common Particle-Fluid Flows In Nature: Bedload Transport In Rivers And Debris Flows In Upland Regions

University of Minnesota Ph.D. dissertation. May 2020. Major: Civil Engineering. Advisor: Kimberly Hill. 1 computer file (PDF); x, 160 pages.This work performed for the research describes in this dissertation concerns particle entrainment in two common particle-fluid flows in nature: 1) bedload transport in rivers, and 2) debris flows in steep upland regions. The bedload transport work addressed here concerns height-dependent entrainment from a bed of a channelized flow. Towards this, we perform distinct element method (DEM) simulations to study the roles of particle size and fluid flow on the transport rate, bed surface variations, and depth-dependent particle entrainment. We do so in the context of a theoretical probabilistic formulation derived to better capture spatial variation in sediment exchange between bed material load and alluvial deposits (Parker et al. (2000)). Our findings allow us to provide a link between the longitudinal bedload transport rate with vertical bed surface statistics and provide closure for a theoretical model designed to model transport and bed-surface exchange in the presence of bed variabilities. The debris flow erosion work here focuses on the effect of grain size distribution of a debris flow on the rate of entrainment of bed material. Towards this, we perform several experiments in a laboratory flume where we measure the relative roles of inclination angle, bed composition, and average flow composition on average and instantaneous erosion dynamics. Most significantly, we find that the infiltration of fine particles into a coarse bed can markedly increase the rate of erosion. Further, the infiltration rate is maximized for intermediate concentrations of small particles in the flow. We show this is due to the interplay of two simultaneous mechanisms: (1) segregation dynamics known as kinetic sieving in the shear flow when there is sufficient agitation of the coarse particles to allow the small particles to sink into the bed and (2) correlated interparticle forces which create sufficient agitation only with an adequately high concentration of coarse particles. In this presentation, we demonstrate how a better understanding of these two processes can contribute to a better understanding of the "sediment cycle" in earth-surface dynamics