566 research outputs found
Exact implicit Solution of Nonlinear Heat Transfer in Rectangular Straight Fin Using Symmetry Reduction Methods
In this paper, the exact implicit solution of the second order nonlinear ordinary differential equation which governing heat transfer in rectangular fin is obtained using symmetry reduction methods. General relationship among the temperature at the fin tip, the temperature gradient at the fin base, the mode of heat transfer, and the fin parameters and ℰ is obtained. Some numerical examples are discussed and it is shown that the temperature of fin increases when approaching from the heat source. The relationship between the fin efficiency and the temperature of fin tip is obtained for any value of the mode of heat transfer . The relationship between the fin efficiency and both the parameter and ε the temperature gradient at the fin base is obtained. To our best knowledge, solutions obtained in this paper are new
The role of losartan and enalapril in the protection against stress-induced gastric mucosal ulceration in rats
Background: Angiotensin II (ANG II) is a stress hormone and its level dramatically increases in the stomach during stress. In addition, it generates reactive oxygen species (ROS) with cellular damage and inflammation. So the aim of this study is to evaluate the mechanism of losartan and enalapril in the prevention of stress-induced gastric ulcer through their action on mucosal prostaglandin (PGs) and antioxidant enzymes and compare between them.Methods: Thirty- six adult male wistar albino rats weighing 180-200 g were divided into 6 groups; n= 6. Groups 1, 2, and 3 were received saline (normal control), losartan (3 mg/kg/day) and enalapril (10 mg/kg/day) i.p respectively for 4 weeks. Groups 4, 5, and 6 were pretreated with saline (ulcer control), losartan (3 mg/kg/day) and enalapril (10 mg/kg/day) i.p respectively for 4 weeks duration. On 29th day, group 4, 5 and 6 were submitted to gastric ulcer by water immersion method, then animals of all groups were sacrificed, stomachs were excised for gross and microscopic examination and determination of the mucosal levels of prostaglandin E2 (PGE2), superoxide dismutase (SOD), nitric oxide (NO) and catalase (CAT).Results: Stress produced gastric ulcer and a significant decrease in all measured gastric parameters compared to normal control group. Pre-treatment of rats with losartan or enalapril decreased the stress-induced alterations in mucosal parameters, but only losartan caused a significant increase in CAT activity in addition.Conclusions: Antagonize the action of ANG II by losartan and enalapril have preventive advantages in stress-induced gastric ulcer and losartan has better influence as it has an additional effect on CAT activity
Gastrografin in the management of adhesive small bowel obstruction in children: a pilot study
Background/purpose Adhesive small bowel obstruction (ASBO) is a common emergency problem in children with previous abdominal surgery. Management protocols usually start with a conservative approach that may be successful in some cases, whereas in others it will end eventually by laparotomy with its associated morbidity and mortality. Our aim was to assess the role of water-soluble contrast, gastrografin, in the conservative management of ASBO. Patients and methods During the period January 2009 to July 2010, 33 patients with ASBO were presented at the Pediatric Surgery Unit at the Ain Shams University Hospitals. Patients who failed to improve after 48 h of conservative management in the absence of signs of strangulation were subjected to gastrografin administration. Patients were evaluated clinically and radiologically to determine the resolution of the adhesive attack, with estimation of hospital stay time. Results An oral administration of gastrografin successfully completed the conservative management in eight of 12 patients (66.6%), thus avoiding surgery and subsequently reducing hospital stay. Conclusion Gastrografin may have a valuable role in the management of ASBO, whether diagnostic or therapeutic, but a randomized controlled trial is needed to prove its effectiveness in reducing surgical intervention rate and hospital stay time.Keywords: adhesive, bowel obstruction, gastrografi
Polycyclic Aromatic Hydrocarbons in Grilled Meats from Restaurants
Polycyclic aromatic hydrocarbons are a group of lipophilic compounds that can be generated during the preparation of food items at elevated temperatures. They are regarded as potentially genotoxic and carcinogenic to human beings, related to increased incidence of breast and colorectal cancers, oxidative DNA injury, and bad effects on children neuro-differentiation. Thus, they are considered a public health concerns. A total of thirty samples of grilled beef steak, beef kofta and chicken (ten each) were collected from different restaurants. The samples were extracted by magnesium sulfate and sodium acetate in acetonitrile then purified in magnesium sulfate, primary, secondary amine and silica gel, and finally measured by gas chromatography-mass spectrometry (GC-MS). Benzo[a]pyrene was recorded with the highest average level (3.63µg/kg) in grilled kofta samples, but it was not detected in chicken samples. On the other hand, PAH4, PAH8 and ƩPAHs content were more abundant in grilled beef steak (5.32, 9.97 and 56.91µg/kg). Meanwhile, they recorded the least concentrations of grilled chicken from different restaurants. Furthermore, benzo[a]pyrene exceeded the permissible limits of the European Commission and Egyptian National Food Safety Authority in grilled kofta samples; further studies are needed to investigate the limits of exposure to these harmful compounds from meats and other food items
Evaporation induced flow inside circular wells
Flow field and height averaged radial velocity inside a droplet evaporating
in an open circular well were calculated for different modes of liquid
evaporation.Comment: 5 page, 3 figures, submitted to European Physical Journal
Design, Synthesis and Biological Evaluation of Syn and Anti-like Double Warhead Quinolinones Bearing Dihydroxy Naphthalene Moiety as Epidermal Growth Factor Receptor Inhibitors with Potential Apoptotic Antiproliferative Action
Our investigation includes the synthesis of new naphthalene-bis-triazole-bis-quinolin-2(1H)-ones 4a–e and 7a–e via Cu-catalyzed [3 + 2] cycloadditions of 4-azidoquinolin-2(1H)-ones 3a–e with 1,5-/or 1,8-bis(prop-2-yn-1-yloxy)naphthalene (2) or (6). All structures of the obtained products have been confirmed with different spectroscopic analyses. Additionally, a mild and versatile method based on copper-catalyzed [3 + 2] cycloaddition (Meldal–Sharpless reaction) was developed to tether quinolinones to O-atoms of 1,5- or 1,8-dinaphthols. The triazolo linkers could be considered as anti and syn products, which are interesting precursors for functionalized epidermal growth factor receptor (EGFR) inhibitors with potential apoptotic antiproliferative action. The antiproliferative activities of the 4a–e and 7a–e were evaluated. Compounds 4a–e and 7a–e demonstrated strong antiproliferative activity against the four tested cancer cell lines, with mean GI50 ranging from 34 nM to 134 nM compared to the reference erlotinib, which had a GI50 of 33 nM. The most potent derivatives as antiproliferative agents, compounds 4a, 4b, and 7d, were investigated for their efficacy as EGFR inhibitors, with IC50 values ranging from 64 nM to 97 nM. Compounds 4a, 4b, and 7d demonstrated potent apoptotic effects via their effects on caspases 3, 8, 9, Cytochrome C, Bax, and Bcl2. Finally, docking studies show the relevance of the free amino group of the quinoline moiety for antiproliferative action via hydrogen bond formation with essential amino acids
Affordable dye sensitizer by waste
Abstract The development of dye sensitizer is growing in line with the increasing demand for renewable energy. A research to obtain a dye sensitizer that is economical, safe, and produces a great value of DSSC efficiency is a challenge unresolved. On the other hand, the efforts for waste reduction are also intensively conducted to create better environment. In this paper, the variation of synthetic dye wastes from batik industries have been successfully applied as dye sensitizer and fabricated on DSSC cells. Congo red (1.0133%) yielded higher efficiency than rhodamine B (0.0126%), methyl orange (0.7560%), and naphthol blue black (0.0083%). The divergence of the efficiency of DSSC is very dependent upon the chromophore group owned by dye. This study has proven that the more chromophore group possessed by dye, the higher the efficiency of DSSC generated. This research concludes that the dye wastes have a bright future to be implemented as dye sensitizer on solar cells
The Plasmodium falciparum STEVOR Multigene Family Mediates Antigenic Variation of the Infected Erythrocyte
Modifications of the Plasmodium falciparum–infected red blood cell (iRBC) surface have been linked to parasite-associated pathology. Such modifications enable the parasite to establish long-lasting chronic infection by evading antibody mediate immune recognition and splenic clearance. With the exception of the well-demonstrated roles of var-encoded PfEMP1 in virulence and immune evasion, the biological significance of other variant surface antigens (rif and stevor) is largely unknown. While PfEMP1 and RIFIN have been located on the iRBC surface, recent studies have located STEVOR at the iRBC membrane where it may be exposed on the erythrocyte surface. To investigate the role of STEVOR in more detail, we have developed antibodies against two putative STEVOR proteins and used a combination of indirect immunofluorescence assays (IFA), live IFA, flow cytometry, as well as agglutination assays, which enable us to demonstrate that STEVOR is clonally variant at the surface of schizont stage parasites. Crucially, expression of different STEVOR on the surface of the iRBC changes the antigenic property of the parasite. Taken together, our data for the first time demonstrate that STEVOR plays a role in creating antigenic diversity of schizont stage parasites, thereby adding additional complexity to the immunogenic properties of the iRBC. Furthermore, it clearly demonstrates that to obtain a complete understanding of how parasite-induced pathology is linked to variation on the surface of the iRBC, focusing the interactions of multiple multigene families needs to be considered
Deoxycholic acid induces the overexpression of intestinal mucin, MUC2, via NF-kB signaling pathway in human esophageal adenocarcinoma cells
<p>Abstract</p> <p>Background</p> <p>Mucin alterations are a common feature of esophageal neoplasia, and alterations in MUC2 mucin have been associated with tumor progression in the esophagus. Bile acids have been linked to esophageal adenocarcinoma and mucin secretion, but their effects on mucin gene expression in human esophageal adenocarcinoma cells is unknown.</p> <p>Methods</p> <p>Human esophageal adenocarcinoma cells were treated 18 hours with 50–300 μM deoxycholic acid, chenodeoxycholic acid, or taurocholic acid. MUC2 transcription was assayed using a MUC2 promoter reporter luciferase construct and MUC2 protein was assayed by Western blot analysis. Transcription Nuclear factor-κB activity was measured using a Nuclear factor-κB reporter construct and confirmed by Western blot analysis for Nuclear factor-κB p65.</p> <p>Results</p> <p>MUC2 transcription and MUC2 protein expression were increased four to five fold by bile acids in a time and dose-dependent manner with no effect on cell viability. Nuclear factor-κB activity was also increased. Treatment with the putative chemopreventive agent aspirin, which decreased Nuclear factor-κB activity, also decreased MUC2 transcription. Nuclear factor-κB p65 siRNA decreased MUC2 transcription, confirming the significance of Nuclear factor-κB in MUC2 induction by deoxycholic acid. Calphostin C, a specific inhibitor of protein kinase C (PKC), greatly decreased bile acid induced MUC2 transcription and Nuclear factor-κB activity, whereas inhibitors of MAP kinase had no effect.</p> <p>Conclusion</p> <p>Deoxycholic acid induced MUC2 overexpression in human esophageal adenocarcinoma cells by activation of Nuclear factor-κB transcription through a process involving PKC-dependent but not PKA, independent of activation of MAP kinase.</p
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