78 research outputs found
Strengthening of Concrete Beams in Shear
Finite element analysis (FEA) is used to predict the behavior of reinforced concrete beams strengthened in shear with fiber reinforced polymer (FRP). To verify and measure the accuracy of the FEM model, the FEA results were compared with both pervious experimental and theoretical results. Two beams were studied simulating the Horsetail Creek Bridge in Oregon, USA. The first one is a control beam with no strengthening fiber. The second one is wrapped with glass fiber reinforced polymer (GFRP) laminates to reinforce the beam in shear. Results were represented by load-strain curves for concrete, steel and fiber. In addition, the load deflection curves and crack patterns developed in the beams were presented. The results showed that FE modeling was accurate in simulating the tested beams. It was also clear that using FRP in strengthening reinforced concrete beams is an effective method in improving shear behavior of the beams
Strengthening of Concrete Beams Using FRP Composites
Finite element analysis (FEA) is used to predict the behavior of reinforced concrete beams strengthened with fiber reinforced polymer (FRP). To verify and measure the accuracy of the FEM model, the current model results were compared with both experimental and theoretical available results. Four beams were studied simulating the Horsetail Creek Bridge, Oregon, USA. The first one is a control beam with no strengthening fiber.The second beam is strengthened with carbon fiber reinforced polymer (CFRP) oriented along the length of the beam to reinforce the flexure behavior. The third beam is wrapped with glass fiber reinforced polymer(GFRP) laminates representing the shear beam. The fourth one is strengthened with CFRP and GFRP laminates representing the flexure-shear beam.The load-strain for concrete, steel and fiber as well were represented and compared. In addition, the load deflection curves and crack patterns were developed and represented. The results showed that the modeling process was accurate in simulating the tested beams. It was also clear that using FRP in strengthening reinforced concrete beams is an effective method in improving both shear and flexural behavior of the beams
Wheat Germ Oil Restores Testicular Function Through Modulation of Oxidative Stress in Male Adult Rats Exposed to Chromium VI
This research was outlined to assess the protective and therapeutic role of wheat germ oil against chromium VI -induced oxidative stress and testicular dysfunction in male adult rats through evaluation of semen picture, measuring the sex hormone levels, oxidative stress markers, DNA fragmentation percentage and histopathological changes in the testes. Twenty-eight adult Wister male rats were assigned into four equal groups: Group 1; Control, group 2; Cr VI, group 3; Cr VI + WGO, and group 4; WGO. WGO showed a significant increment in the RBC, Hb, Ht, WBC and Plts. WGO restored the levels of testicular antioxidant enzymes, NO, MDA as well as GSH. Also, WGO in-combination with Cr VI showed a significant (p<0.05) increase in the levels of testosterone, LH, GnRH hormones and 17β-HSD enzyme, while, FSH was decreased. Data showed that treatment of male rats with WGO and Cr VI caused an increase in sperm count, motility, and decrease in sperm abnormality. Combination of WGO with Cr VI revealed a decrease in the levels of TL, TC, TG and LDL–C, while, HDL–C was increased. Rats administrated with WGO in-combination with Cr VI exhibited a slight improvement in testicular DNA integration compared to Cr VI-treated group. Further, co-administration of WGO + Cr VI revealed a slight improvement in the pathological alterations; the cellular layers of the seminiferous tubules more or less near to the normal structure. It was concluded that wheat germ oil can be an effective antioxidant in modulating Cr VI-induced male infertility, and may lead to improve the male reproductive performance
Right mini-thoracotomy versus median sternotomy for mitral valve replacement
Background: The advantages of minimally invasive mitral valve surgery over the conventional approach is still debated. This study aimed to evaluate early outcomes after mitral valve replacement (MVR) using the right mini-thoracotomy (RMT) versus median sternotomy (MS).
Methods: We prospectively included 60 patients who had MVR from May 2015 to June 2017. We classified patients into two groups; Group A (n= 30) had RMT, and Group B (n= 30) had MS. Postoperative pain score, wound satisfaction, and clinical and echocardiographic outcomes were compared between both groups.
Results: The mean age was 39.90 ± 12.34 years in Group A and 45.75 ± 13.10 years in Group B (p= 0.08). Preoperative and echocardiographic data showed no statistical significance difference between the groups. Group A had longer aortic cross-clamp (118.85 ± 40.56 vs. 70.75 ± 24.81 minutes, p<0.001) and cardiopulmonary bypass times (186.70 ± 67.44 vs. 104.65 ± 42.60 minutes, p<0.001). Group B had more blood loss (565 ± 344.3 vs. 241.5 ±89.16 ml/24 hours, p<0.001). The median pain score was 1 (range: 1- 3) in Group A and 4 (2- 8) in Group B (p<0.001), and the median wound satisfaction was 1.5 (1- 4) in Group A and 4 (1- 7) in Group B (p<0.001). Wound infection occurred in 1 (3.3%) patient in Group A and 6 (20%) patients in Group B (p=0.04).
Conclusion: Mitral valve replacement through the right mini-thoracotomy could be a safe alternative to median sternotomy. The right mini-thoracotomy was associated with longer operative times but better pain and wound satisfaction scores and lower wound infection
How effective is stretching in maintaining range of movement for children with cerebral palsy?
YesBackground: Cerebral Palsy (CP) is the most common childhood disorder affecting four percent of children born in the UK. It is common for children with CP to have reduced range of movement (ROM) due to spasticity and contractures. Stretching is commonly used in physiotherapy programmes to manage this.
Aim: This critical review aims to evaluate the evidence base behind the use of stretching for children with CP.
Methods: A systematic literature search of AMED, CINAHL, MEDLINE and Cochrane Library Trials was conducted. Returned searches were assessed against strict criteria according to a predefined PICOS (Population, Intervention, Comparison, Outcome, Study). These studies were then critically appraised to assess the validity, reliability and clinical relevance.
Findings: There is evidence supporting the use of stretching in children with CP. However there is also some evidence to suggest very little or no positive change. All of the included studies have methodological limitations, which questions the validity of the results.
Conclusions/Recommendations: The research suggests some positive outcomes for the use of stretching in CP, studies that did not find positive outcomes found no adverse effects; however further research in the area is required to validate the effectiveness of stretching to maintain ROM in children with CP
Phylogeny and functional diversity of halophilic microbial communities from a thalasso environment
The El-Rawda solar saltern, located in North Sinai, Egypt, is formed through the process of water evaporation from the Bradawil lagoon. This evaporation leads to the precipitation of gypsum, halite minerals, and salt flats, which subsequently cover the southern and eastern areas of the lagoon. This study employed the shotgun metagenomic approach, the illumine platform, and bioinformatic tools to investigate the taxonomic composition and functional diversity of halophilic microbial communities in solar saltern. The metagenomic reads obtained from the brine sample exhibited a greater count compared to those from the sediment sample. Notably, the brine sample was primarily characterized by an abundance of archaea, while the sediment sample displayed a dominant abundance of bacteria. Both samples exhibited a relatively low abundance of eukaryotes, while viruses were only found in the brine sample. Furthermore, the comparative analysis of functional pathways showed many important processes related to central metabolism and protein processing in brine and sediment samples. In brief, this research makes a valuable contribution to the understanding of very halophilic ecosystems in Egypt, providing insights into their microbial biodiversity and functional processes
Pigment epithelium-derived factor inhibits retinal microvascular dysfunction induced by 12/15-lipoxygenase-derived eicosanoids
We recently demonstrated that 12/15-lipoxygenase (LOX) derived metabolites, hydroxyeicosatetraenoic acids (HETEs), contribute to diabetic retinopathy (DR) via NADPH oxidase (NOX) and disruption of the balance in retinal levels of the vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF). Here, we test whether PEDF ameliorates retinal vascular injury induced by HETEs and the underlying mechanisms. Furthermore, we pursue the causal relationship between LOX–NOX system and regulation of PEDF expression during DR. For these purposes, we used an experimental eye model in which normal mice were injected intravitreally with 12-HETE with/without PEDF. Thereafter, fluorescein angiography (FA) was used to evaluate the vascular leakage, followed by optical coherence tomography (OCT) to assess the presence of angiogenesis. FA and OCT reported an increased vascular leakage and pre-retinal neovascularization, respectively, in response to 12-HETE that were not observed in the PEDF-treated group. Moreover, PEDF significantly attenuated the increased levels of vascular cell and intercellular adhesion molecules, VCAM-1 and ICAM-1, elicited by 12-HETE injection. Accordingly, the direct relationship between HETEs and PEDF has been explored through in-vitro studies using Müller cells (rMCs) and human retinal endothelial cells (HRECs). The results showed that 12- and 15-HETEs triggered the secretion of TNF-α and IL-6, as well as activation of NFκB in rMCs and significantly increased permeability and reduced zonula occludens protein-1 (ZO-1) immunoreactivity in HRECs. All these effects were prevented in PEDF-treated cells. Furthermore, interest in PEDF regulation during DR has been expanded to include NOX system. Retinal PEDF was significantly restored in diabetic mice treated with NOX inhibitor, apocynin, or lacking NOX2 up to 80% of the control level. Collectively, our findings suggest that interfering with LOX–NOX signaling opens up a new direction for treating DR by restoring endogenous PEDF that carries out multilevel vascular protective functions.National Eye Institute 5R01EY023315-02, Qatar National Research Fund NPRP 4-1046-3-284, and Vision Discovery Institute (MA), Mr. and Mrs. Richards travel award (ASI)
A lipidomic screen of hyperglycemia-treated HRECs links 12/15-Lipoxygenase to microvascular dysfunction during diabetic retinopathy via NADPH oxidase
Retinal hyperpermeability and subsequent macular edema is a cardinal feature of early diabetic retinopathy (DR). Here, we investigated the role of bioactive lipid metabolites, in particular 12/15-lipoxygenase (LOX)-derived metabolites, in this process. LC/MS lipidomic screen of human retinal endothelial cells (HRECs) demonstrated that 15-HETE was the only significantly increased metabolite (2.4 ± 0.4-fold, P = 0.0004) by high glucose (30 mM) treatment. In the presence of arachidonic acid, additional eicosanoids generated by 12/15-LOX, including 12- and 11-HETEs, were significantly increased. Fluorescein angiography and retinal albumin leakage showed a significant decrease in retinal hyperpermeability in streptozotocin-induced diabetic mice lacking 12/15-LOX compared with diabetic WT mice. Our previous studies demonstrated the potential role of NADPH oxidase in mediating the permeability effect of 12- and 15-HETEs, therefore we tested the impact of intraocular injection of 12-HETE in mice lacking the catalytic subunit of NADPH oxidase (NOX2). The permeability effect of 12-HETE was significantly reduced in NOX2−/− mice compared with the WT mice. In vitro experiments also showed that 15-HETE induced HREC migration and tube formation in a NOX-dependent manner. Taken together our data suggest that 12/15-LOX is implicated in DR via a NOX-dependent mechanism.National Institutes of Health Grant 5R01EY023315 and National Priorities Research Program Grant 4-1046-3-284 from the Qatar National Research Fund (a member of Qatar Foundation). This study was also supported in part by the National Center for Research Resources, National Institutes of Health Grant S10RR027926
Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study
Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised
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