93 research outputs found
Local scour due to free fall jets in non-uniform sediment
Get PDFAbstractThe results of experiments on the local scour due to free fall jets are presented in this paper. Experiments were conducted for various values of the densimetric Froude number, the relative tailwater depth, the relative drop height and the relative sediment size. It has been found that by increasing the sediment non-uniformity parameter the scour hole parameters decrease. Moreover, in non-uniform sediment, d90 can be used instead of d50 in the densimetric Froude number of the jet. By using the present and previous experimental data, new equations for the scour parameters were developed. The validity of the developed equations was checked by available prototype data on the scour depth
Antioxidant role of oleuropein on midbrain and dopaminergic neurons of substantia Nigra in aged rats
Get PDFBackground: Oleuropein is a phenolic compound which is present in the olive leaf extract. The purpose of the present study was to investigate the neuroprotective effect of oleuropein as an antioxidant agent on the substantia nigra in aged rats. Methods: Twenty 18-month-old Wistar rats (450-550 g) were randomly divided into control and experimental groups. The experimental group received a daily single dose of 50 mg/kg of oleuropein by oral gavage for 6 months. The control group received only distilled water. All rats were sacrificed two hours after the last gavage and the brains were removed and midbrains were cut. One part of the midbrains were homogenized and centrifuged. The tissue supernatant was assayed for lipid peroxidation (LPO) and antioxidant enzyme activities. The other part of midbrains fixed and embedded in paraffin, then processed for Nissl and immunohistochemistry (IHC) staining. Data was analyzed using SPSS by t-test. Differences were considered significant for P<0.05. Results: The level of LPO in midbrain of the rats was decreased significantly in the experimental group, but superoxide dismutase, catalase and glutathione peroxidase activities were increased in experimental group compared to control group (P<0.05). Morphometric analyses showed significantly that the experimental group had more neurons in substantia nigra pars compacta (SNc) either in Nissl or IHC staining when compared to control (P<0.05). Conclusion: The results of the present study indicate that treatment of the old rats with oleuropein reduces the oxidative damage in SNc by increasing the antioxidant enzyme activities
Low levels of antibodies against common viruses associate with anti-citrullinated protein antibody-positive rheumatoid arthritis; implications for disease aetiology
Full text linkCD28null CD4 T-cell expansions in autoimmune disease suggest a link with cytomegalovirus infection
Get PDFImmunosenescence is thought to contribute to the increase of autoimmune diseases in older people. Immunosenescence is often associated with the presence of an expanded population of CD4 T cells lacking expression of CD28 (CD28null). These highly cytotoxic CD4 T cells were isolated from disease-affected tissues in patients with rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, or other chronic inflammatory diseases and their numbers appeared to be linked to disease severity. However, we recently demonstrated that the common herpes virus, cytomegalovirus (CMV), not ageing, is the major driver of this subset of cytotoxic T cells. In this review, we discuss how CMV might potentiate and exacerbate autoimmune disease through the expansion of CD28null CD4 T cells
Androgen Receptor Drives Cellular Senescence
Get PDFThe accepted androgen receptor (AR) role is to promote proliferation and survival of prostate epithelium and thus prostate cancer progression. While growth-inhibitory, tumor-suppressive AR effects have also been documented, the underlying mechanisms are poorly understood. Here, we for the first time link AR anti-cancer action with cell senescence in vitro and in vivo. First, AR-driven senescence was p53-independent. Instead, AR induced p21, which subsequently reduced ΔN isoform of p63. Second, AR activation increased reactive oxygen species (ROS) and thereby suppressed Rb phosphorylation. Both pathways were critical for senescence as was proven by p21 and Rb knock-down and by quenching ROS with N-Acetyl cysteine and p63 silencing also mimicked AR-induced senescence. The two pathways engaged in a cross-talk, likely via PML tumor suppressor, whose localization to senescence-associated chromatin foci was increased by AR activation. All these pathways contributed to growth arrest, which resolved in senescence due to concomitant lack of p53 and high mTOR activity. This is the first demonstration of senescence response caused by a nuclear hormone receptor
The Effects of Celecoxib on Rotenone-Induced Rat Model of Parkinson’s Disease: Suppression of Neuroinflammation and Oxidative Stress-Mediated Apoptosis
No full textExperimental study on Scour due to simultaneous wall and impinging circular jet
No full textIn this study the scour mechanism and the effect of some of the important parameters such as jet velocities, impinging jet distance from the upstream wall and tailwater depth on the longitudinal scour profile due to 3d simoultaneous wall and impinging jet are investigated experimentally. Experiments were conducted in a channel 10 m long, 1 m height and 0.57 m width. For generating jet flow, two pipes with 1 cm inside diameter and 2 m long were used. Uniform sediment with median size of 1.05 mm was used as the bed material. The experiments showed that the jet distances, jet velocities and tailwater depth have significant effect on scour hole profile. Depending on the jet velocities, tailwater depth and the distance of the impinging jet from the upstream wall, two types of longitudinal scour profiles are observed
Antioxidant Effects of Olive Leaf Extract in Prevention of Alzheimer’s Disease and Parkinson’s Disease
No full textEXPERIMENTAL INVESTIGATION OF THE FLOWFIELD AROUND STRAIGHT SPUR DIKES LOCATED IN A DIFFERENT LOCATION OF 90 BEND
No full textSpur dikes deflect the approaching flow to the far bank and decreases the sediment deposition. The scour hole formation and flow field features around spur dikes are interesting subjects in hydraulic engineering. In this paper, the flow field around straight spur dikes in a 90\u{1d52} sharp bend was investigated experimentally. Three different experiments were conducted in a prismatic channel with 90\u{1d52} bend at Tarbiat Modares University Tehran, Iran. In each experiment, a straight spur dike was attached to the outer bank in different angles with respect to the beginning of the bend. The flow fields were measured using Vectrino apparatus. In each point, the velocity was measured in 100 HZ frequency for 3 min. Despiking process was done using previous research approach. The spectral analysis, mean flow analysis, higher correlation analysis, bed shear analysis, turbulent intensity analysis, power spectrum analysis, and quadrant analysis were conducted. Results confirm the existence of the secondary flow in the bend, horse shoe vortex, and recirculation flow region. There is no strong difference between the mean flow fields around the spur dikes. Ejection and sweep events have the main role in shear layer regions, and the interactions are the dominant processes in the downstream recirculation zone. The spectral analysis confirms the existence of the inertial subrange for some frequency range. Some peaks are observed in power spectrum graphs that may, due to the vortex shedding process, confirm the ability of the flow for sediment transport. The bed shear stress based on linear relationship between bed shear stress and turbulent kinetic energy and bed shear stress and vertical velocity fluctuation in vertical direction cannot predict the scour potential region accurately. In addition, the contribution of the ejection events in Reynolds stresses may be one of the important reasons in sediment suspension in the initial time of scour process
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