62 results on '"A.A. Sarhan"'
Search Results
2. Evaluation of Fecal M2PK as a Diagnostic Marker in Colorectal Cancer
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Runia Fouad El-Folly, Hani E Seddik, Mohamed Darwish El-Talkawy, Hisham Khalil Dabbous, Yosry Abd El-Rahman Mohamed, Mohammed A.A. Sarhan, and Dina Johar
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Adult ,Male ,medicine.medical_specialty ,Colorectal cancer ,Pyruvate Kinase ,Colonoscopy ,Gastroenterology ,Adenomatous Polyps ,Feces ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Biopsy ,Biomarkers, Tumor ,medicine ,Humans ,Early Detection of Cancer ,Aged ,medicine.diagnostic_test ,business.industry ,Fecal occult blood ,Complete blood count ,Gold standard (test) ,Middle Aged ,Prognosis ,medicine.disease ,digestive system diseases ,ROC Curve ,Oncology ,Case-Control Studies ,Occult Blood ,030220 oncology & carcinogenesis ,Erythrocyte sedimentation rate ,Colorectal Polyp ,Female ,030211 gastroenterology & hepatology ,Colorectal Neoplasms ,business ,Follow-Up Studies - Abstract
Invasive colonoscopy is the gold standard for patients at risk for colorectal cancer. However, the need for non-invasive and specific markers is required. To evaluate the sensitivity of the glycolytic pyruvate kinase isoenzyme type M2 dimer (M2PK) as a diagnostic biomarker for colorectal cancer (CRC) and adenomatous colorectal polyps (CRP) screening. Case-control. Twenty patients with CRC, 20 patients with CRP (lack criteria for colonic cancer by biopsy), and 20 normal subjects. Complete blood count (CBC), erythrocyte sedimentation rate (ESR), tumor markers: carcino embryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9), fecal occult blood test (FOBT), and fecal M2PK. Pelvic and abdominal ultrasound (US), colonoscopy, and a histopathological examination. Only weight loss and cachexia were significantly associated with CRC than CRP or control groups. M2PK was the most sensitive and specific test in differentiating CRC from CRP and the control subjects (sensitivity = 75%, specificity = 100%). (1) The selection of cases for three well-matched groups, as to perform colonoscopy in well-prepared cases and conditions. (2) Replicates in more than 20 cases for confirmation at the expense of enrolling new patients. (3) The cost associated with tumor markers analysis. Fecal M2PK can be used as a precolonoscopy screening test for CRC patients, and is superior to other tumor markers, and in indicating the progress of colorectal adenomas > 1 cm. Thus being cost-effective and easy-to-perform test, it is a feasible tool to preselect patients who require colonoscopy.
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- 2018
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3. Glycogen synthase kinase 3β inhibitors prevent hepatitis C virus release/assembly through perturbation of lipid metabolism
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Michael Houghton, Mohammed A.A. Sarhan, Andrew Mason, Mohamed S. Abdel-Hakeem, and D. Lorne Tyrrell
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0301 basic medicine ,Hepatitis C virus ,viruses ,Science ,Hepacivirus ,Biology ,Virus Replication ,medicine.disease_cause ,Article ,Virus ,Cell Line ,03 medical and health sciences ,Apolipoproteins E ,GSK-3 ,medicine ,Humans ,Urea ,Apolipoproteins B ,Glycogen Synthase Kinase 3 beta ,Multidisciplinary ,Virion ,Lipid metabolism ,Lipid Metabolism ,Hepatitis C ,Virology ,Molecular biology ,digestive system diseases ,3. Good health ,NS2-3 protease ,Thiazoles ,030104 developmental biology ,Viral replication ,Virion assembly ,Cell culture ,Medicine ,Lithium Chloride - Abstract
Direct acting antivirals against hepatitis C virus (HCV) have markedly improved cure rates in the past few years. However, they are expensive, with only few targeting host cell factors, and affecting virus assembly and release. Huh7.5 cells infected with a JFH-1 clone of HCV were treated with two different glycogen synthase kinase (GSK3)-β inhibitors; AR-A014418 and lithium chloride. Intra- and extracellular HCV virions and specific infectivity was determined using real-time RT-PCR and TCID50, and changes in lipid production were identified by enzyme-linked immunoassay and mass spectrometry analyses. Similarly, effect on two HCV replicon cells were identified by the luciferase activity. Although there was limited effect on virus replication in Huh7.5 cells and replicons, Huh7.5 cells treated with GSK3β inhibitors produced significantly less viral particles in comparison to untreated cells. In addition, the treated cells synthesized significantly lower amounts of ApoB and trapped the ApoE lipoproteins in the cells. In conclusion, our study suggests that GSK3β plays a pivotal role in HCV virion assembly and release mediated in part through inhibition of apolipoprotein synthesis.
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- 2017
4. New core@shell nanogel based 2-acrylamido-2-methyl-1-propane sulfonic acid for preconcentration of Pb(II) from various water samples
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Ayman Mohamdy Atta, A.A. Sarhan, Kamel R. Shoueir, and Magda A. Akl
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chemistry.chemical_classification ,Vinyl alcohol ,Chromatography ,Langmuir adsorption model ,Emulsion polymerization ,02 engineering and technology ,010501 environmental sciences ,Sulfonic acid ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ion ,symbols.namesake ,chemistry.chemical_compound ,Adsorption ,chemistry ,Propane ,symbols ,0210 nano-technology ,0105 earth and related environmental sciences ,Water Science and Technology ,Nuclear chemistry ,Nanogel - Abstract
Poly(vinyl alcohol) core coated with poly(2-acrylamido-2-methyl-1-propanesulfonic acid-co-N-isopropylacrylamide) shell to produce well-define PVA@P(AMPS-co-NIPAm) core shell nanogels with a core of 25 ± 0.5 nm and shell of 5 ± 0.5 nm. The synthetic approach was produced by a surfactant free emulsion polymerization (SFEP). The specific area was found to be 1685.8 m2/g. The nanogels were studied in a batch adsorption for removal of Pb(II) ions and characterized by SEM, TEM, TGA and BET measurements. The results showed that the adsorption equilibrium data fitted the Langmuir isotherm and the kinetic studies are well described by the pseudo-second-order kinetic model. The Pb(II) maximum adsorption was 510.2 (mg/g) for PVA@P(90AMPS-co-10NIPAm) (wt.: wt%). The PVA@P(AMPS-co-NIPAm) nanogels were applied for extracting of Pb(II) in real different environmental water samples successfully with high recoveries reaches 104.4%.
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- 2016
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5. Synthesis of monodisperse core shell PVA@P(AMPS-co-NIPAm) nanogels structured for pre-concentration of Fe(III) ions
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A.A. Sarhan, Ayman M. Atta, Magda A. Akl, and Kamel R. Shoueir
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Vinyl alcohol ,Materials science ,Dispersity ,Acrylic Resins ,Nanogels ,02 engineering and technology ,010402 general chemistry ,Ferric Compounds ,Waste Disposal, Fluid ,01 natural sciences ,Chemistry Techniques, Analytical ,Polyethylene Glycols ,Water Purification ,Ion ,Core shell ,chemistry.chemical_compound ,symbols.namesake ,Adsorption ,Microscopy, Electron, Transmission ,X-Ray Diffraction ,Spectroscopy, Fourier Transform Infrared ,Polymer chemistry ,Polyethyleneimine ,Environmental Chemistry ,Waste Management and Disposal ,Water Science and Technology ,Ions ,Temperature ,Langmuir adsorption model ,Hydrogels ,General Medicine ,Hydrogen-Ion Concentration ,Data matching ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Chemical engineering ,Polyvinyl Alcohol ,Microscopy, Electron, Scanning ,symbols ,Epichlorohydrin ,0210 nano-technology ,Pre concentration ,Water Pollutants, Chemical - Abstract
Core shell-structured poly(vinyl alcohol) @ poly(2-acrylamido-2-methyl-1-propane-sulfonic acid-co-N-isopropylacrylamide) PVA@P(AMPS-co-NIPAm) spheres are synthesized. The well-defined PVA@P(AMPS-co-NIPAm) core shell nanogels with diameter nearly 30 nm enriches Fe(III), and the nanogels are characterized by FT-IR, TEM, SEM and X-ray diffraction (XRD). The many factors affecting adsorption were successfully investigated. The maximum capacity of Fe(III) ions was 320 (mg/g) for PVA@P(90AMPS-co-10NIPAm) (wt.: wt%). The equilibrium data matching well with the Langmuir model and the pseudo-second-order form described the adsorption process better than the pseudo-first-order model. Findings of the present study highlight using a simple synthesis of PVA@P(AMPS-co-NIPAm) nanogels as superior and recyclable nanoadsorbents.
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- 2016
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6. Adsorption studies of Cu2+ onto poly (vinyl alcohol)/poly (acrylamide-co-N-isopropylacrylamide) core–shell nanogels synthesized through surfactant-free emulsion polymerization
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A.A. Sarhan, Magda A. Akl, Kamel R. Shoueir, and Ayman M. Atta
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Vinyl alcohol ,Aqueous solution ,Chemistry ,Process Chemistry and Technology ,General Chemical Engineering ,Emulsion polymerization ,Langmuir adsorption model ,Nanoparticle ,Filtration and Separation ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,symbols.namesake ,Adsorption ,Chemical engineering ,Polymer chemistry ,symbols ,Freundlich equation ,0210 nano-technology ,Nanogel - Abstract
Poly (vinyl alcohol) (PVA) nanoparticle core and poly (acrylamide-co-N-isopropylacrylamide) P(AAm-co-NIPAm) hydrogel shell were fabricated to produce well-defined PVA/P(AAm-co-NIPAm) core–shell nanogels using Surfactant Free Emulsion Polymerization (SFEP). The nanogel was characterized by the FTIR, TEM TGA thermogram and SEM techniques. The adsorbent was utilized for Cu2+ removal from aqueous solution. Batch adsorption process indicated that 0.9 mol% PAAm nanogel exhibited higher adsorption affinity toward Cu2+. The kinetics parameters were investigated according to the pseudo-first-order, pseudo-second-order and intraparticle diffusion rate models. The adsorption equilibrium match with Langmuir adsorption isotherm rather than Freundlich isotherm. The Cu2+ loaded nanogels were effectively desorbed using 0.1 mol/l from HCl as stripping agent.
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- 2016
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7. A Novel Approach to Prepare Poly(Vinyl Acetate)/Ag Nanocomposite for Effective Antimicrobial Coating Applications
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D. M. Ayad, Mai Youssef, Ahmed M. Youssef, and A.A. Sarhan
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Polyvinyl acetate ,Materials science ,Nanocomposite ,Polymers and Plastics ,organic chemicals ,General Chemical Engineering ,Materials Science (miscellaneous) ,technology, industry, and agriculture ,Emulsion polymerization ,macromolecular substances ,engineering.material ,Antimicrobial ,Antibacterial coating ,Silver nanoparticle ,chemistry.chemical_compound ,chemistry ,Coating ,Chemical engineering ,Polymer chemistry ,Materials Chemistry ,Vinyl acetate ,engineering - Abstract
Polyvinyl acetate nanocomposites were successfully prepared based on silver nanoparticles. First, silver nanoparticles were directly prepared during the in situ emulsion polymerization of vinyl ace...
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- 2015
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8. Effect of White Tea Extract on Antioxidant Enzyme Activities of Streptozotocin –Induced Diabetic Rats
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Ali A. Al-Shati, Ahlam A. M. Al-Shiekh, and Mohammed A.A. Sarhan
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chemistry.chemical_classification ,medicine.medical_specialty ,Antioxidant ,biology ,medicine.medical_treatment ,Glutathione peroxidase ,Streptozotocin ,medicine.disease ,Lipid peroxidation ,Superoxide dismutase ,Glibenclamide ,chemistry.chemical_compound ,Endocrinology ,chemistry ,Catalase ,Diabetes mellitus ,Internal medicine ,medicine ,biology.protein ,medicine.drug - Abstract
Article History Tea is the second most popular drink in the world after water, and many studies have highlighted the effects of drinking tea. Therefore, the aim of this study was to explore the effects of white tea extract on the antioxidant enzymes activity including superoxide dismutase (SOD), glutathione peroxidase (GSH-px), and catalase (CAT). A significant decrease was observed in serum and liver SOD, GSH-px, and CAT activities in the diabetic control rats compared with the nondiabetic control ones. However, a significant increase in SOD, GSH-px, and CAT activities (serum and liver) was observed in the diabetic groups treated with white tea extract or Glibenclamide as compared to the diabetic control group. In conclusion, the present findings indicated that white tea extract has an enhancing effect on the antioxidant enzyme activities (SOD, CAT, and GSH-px) in STZ-induced diabetic rats.
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- 2014
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9. Biochemical and molecular studies on the possible influence of the Brassica oleracea and Beta vulgaris extracts to mitigate the effect of food preservatives and food chemical colorants on albino rats
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Mohammed A.A. Sarhan, Ali A. Shati, and Fahmy G. Elsaid
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Antioxidant ,medicine.medical_treatment ,Sodium nitrite ,Sunset yellow ,Superoxide dismutase ,chemistry.chemical_compound ,Oral administration ,medicine ,Food science ,chemistry.chemical_classification ,biology ,Agricultural and Biological Sciences(all) ,Glutathione peroxidase ,Broccoli ,food and beverages ,Beet ,Glutathione ,biology.organism_classification ,chemistry ,Biochemistry ,Urea ,biology.protein ,Brassica oleracea ,Antioxidant enzymes ,Original Article ,Gene expression ,General Agricultural and Biological Sciences - Abstract
This study aimed to investigate the biochemical influence of broccoli and beet extracts on selected individual additives NaNO2 or sunset yellow treated rats, in addition to the gene expression of some antioxidant enzymes. Forty-two male rats were assigned to seven groups of six rats in each group. The control group was fed a diet without an additive for four weeks. Group (2) received NaNO2, groups (3) received NaNO2 co-administered with broccoli extract (4) NaNO2 co-administered with beet extracts, Group (5) received sunset yellow, Group (6) received sunset yellow co-administered with broccoli extract, and Group (7) received sunset yellow co-administered with beet extract, for four weeks. At the end of the experiment, blood, liver, kidney, and brain samples were taken for biochemical and/or molecular analysis. The mRNA expression of antioxidant enzymes was determined by reversing transcriptase-polymerase chain reaction (RT-PCR). The obtained results revealed that rats co-administered with beet or broccoli extracts had a significant decrease in serum levels of AST, ALT, ALP, urea, total lipids, and triglycerides, as well as a significant increase in reduced glutathione (GSH), glutathione peroxidase (GSH-px), and superoxide dismutase (SOD) enzyme activities, compared to the normal control group. Oral administration of NaNO2 or sunset yellow caused a significant increase in serum levels of AST, ALT, ALP, urea, total lipids, and triglycerides, as well as a significant decrease in GSH, GSH-px, and SOD compared to the positive group. In conclusion, this study showed that broccoli and beet extracts have a protective effect against NaNO2 or sunset yellow in rat treated groups.
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- 2014
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10. ABO-Rh Blood Groups Distribution among King Khalid University Girls Students: A Prevalence Study
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Mona A. Almushait, Saad M. Bin-Dajem, and Mohammed A.A. Sarhan
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Pediatrics ,medicine.medical_specialty ,Blood transfusion ,business.industry ,medicine.medical_treatment ,Effective management ,Community support ,Family medicine ,ABO blood group system ,Distribution pattern ,Medicine ,business ,Female students ,Erythroblastosis fetalis ,Rh blood group system - Abstract
Objective: A questionnaire–based prevalence study was carried out on a random sample from various girls’ science college, KingKhalidUniversity, to find out the distribution pattern of ABO and Rh blood groups among Saudi females, which would not only help in blood transfusion services but also eliminate the risk of erythroblastosis fetalis in the neonates. Method: The procedure for this study was done by giving the questionnaire to 3287 female students. Each participant filled out the questionnaire and gave it back after answering all the questions. The participants were volunteered to fill out the questionnaire. Results: Of the 3287 female students enrolled in this study, 965 students know their blood groups. Amongst ABO system, blood group O was the most common (57.31%) followed by A (32.74%), B (9.22%), and AB (0.73%), respectively. Regarding rhesus system, Rhesus positive was more common (90.3%) than Rhesus negative (9.7%). Conclusion: The current study documents ABO and Rhesus blood group distribution pattern amongst King Khalid University Girls Students. Findings ensured that there is need for educational and community support program for effective management of medical emergencies.
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- 2014
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11. Characterization and Identification of Moderately Thermophilic Bacteria Isolated from Jazan Hot Springs in Saudi Arabia
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Saad Alamrri and Mohammed A.A. Sarhan
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Hot spring ,Phylogenetic tree ,Sequence analysis ,GenBank ,Thermophile ,Biology ,16S ribosomal RNA ,Gene ,Homology (biology) ,Microbiology - Abstract
Article History Three new moderately thermophilic bacteria were isolated from three (Al-Khawbah, Bani Malik, and Al- Bozah) hot springs located in Jazan district, south-western of Saudi Arabia. The isolates were identified by the sequence analysis of the 16S rRNA gene. The 16S rRNA gene sequence alignment with GenBank resulted in a percent identity (% ID) with closest GenBank match of 98% suggesting that the isolates are new strains within the branching of well-defined genus Bacillus. The phylogenetic analysis of these strains using their 16S rDNA sequence data showed that strains SA and SS30 had highest homology (98%) with B. licheniformis, whereas strain SA09 showed 98% similarity with B. subtilis. The morphological, biochemical, and physiological characteristics of the isolates were also studied. They were aerobic, gram-positive, rod-shaped, and moderately thermophilic bacteria (with an optimum growth temperature of 45-50˚C, and pH of 6).
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- 2014
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12. Antibiotics Sensitivity Profile Towards Staphylococcus hominis in Assir Region of Saudi Arabia
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H. A. Musaa, Nazar M Abdalla, Amani A Osman, Waleed O Haimour, and Mohammed A.A. Sarhan
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biology ,business.industry ,medicine.drug_class ,Antibiotics ,Erythromycin ,biology.organism_classification ,medicine.disease_cause ,Microbiology ,Ciprofloxacin ,Penicillin ,Ampicillin ,Staphylococcus hominis ,medicine ,Coagulase ,business ,Staphylococcus ,medicine.drug - Abstract
Staphylococcus hominis is a Gram-positive , spherical cells in clusters and coagulase -negative bacterial. It commonly occurs as a harmless commensal on human skin, occasionally causes nosocomial or community acquired infection specially in immuno-compromised patients. Nowadays almost all Staphylococcus species have multidrug resistance. In this study, a total of ten out of one hundred fifty nasal swabs at Assir Central Hospital General Lab during the period of April 2011- July 2011 proved to be Staphylococcus spp. and identified as Staphylococcus hominis patients of different sex and age groups with variable systemic infections ( e.g . RTI, UTI, CNS). The samples were tested by bactech, culture media, antibiotics sensitivity using diffusion disc test (MIC) and molecular polymerase chain reaction ( PCR) for confirmation of Staphylococcal species and detection of the Mec A gene. Clinical, demographic and laboratory data were collected and analyzed by SPSS. Drugs found to be resistant to all patients were penicillin, erythromycin, ampicillin, cifoxine and carbinicillin. Whereas cotrimexazole, amikacine and vancomycine were sensitive to all patients. Only 10% of patients were sensitive to methotrexate and cefaclor. Drugs that showed variable sensitivity pattern among patients were tetracyclin, fucidin, augmentin, gentamycin and ciprofloxacin. © 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v5i1.11704 J. Sci. Res. 5 (1), 171-183 (2013)
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- 2012
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13. Ice nucleation protein as a bacterial surface display protein
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Mohammed A.A. Sarhan
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chemistry.chemical_classification ,INP ,Cell ,Pseudomonas syringae ,Anchoring ,RNA ,Peptide ,Biology ,Molecular biology ,Phenotype ,General Biochemistry, Genetics and Molecular Biology ,surface display ,chemistry.chemical_compound ,medicine.anatomical_structure ,lcsh:Biology (General) ,chemistry ,Genotype ,medicine ,Biophysics ,anchoring motifs ,General Agricultural and Biological Sciences ,lcsh:QH301-705.5 ,DNA - Abstract
Surface display technology can be defined as that phenotype (protein or peptide) which is linked to a genotype (DNA or RNA) through an appropriate anchoring motif. A bacterial surface display system is based on expressing recombinant proteins fused to sorting signals (anchoring motifs) that direct their incorporation on the cell surface.
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- 2011
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14. Lack of micronuclei formation in bone marrow of rats after oral exposure to thiocyclam insecticide
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Kamel A. Saleh, Mohammed A.A. Sarhan, and Serap Celikler
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Pathology ,medicine.medical_specialty ,Adult male ,Agricultural and Biological Sciences(all) ,business.industry ,Pharmacology ,Rat Bone Marrow ,medicine.disease_cause ,medicine.anatomical_structure ,Micronucleus ,In vivo ,Thiocyclam ,Micronucleus test ,Medicine ,Bone marrow ,Original Article ,Genotoxicity ,General Agricultural and Biological Sciences ,business ,Insecticide - Abstract
In this study, a nereistoxin analogue insecticide, thiocyclam, was administered to adult male albino rats by gavage dose of 135, 270 and 540 mg/kg b.w. repeated for 5 days at 24 h intervals. Control animals received only water. Thiocyclam was tested for its potential to cause genotoxic effects in rat bone marrow cells using an in vivo micronucleus assay. After 24 h of the last treatment, rats from all dose levels were sacrificed. Bone marrow cells were collected and assayed for the presence of micronuclei. Thiocyclam did not cause any increase in the incidence of micronucleated polychromatic erythrocytes in rats bone marrow at any of the dose levels. The polychromatic erythrocytes/normochromatic erythrocytes (PCE:NCE) ratio was found to be in the range from 0.50 ± 0.11 to 0.55 ± 0.02. The results of this study demonstrate that the effect of thiocyclam is not significant in the rat in vivo micronucleus assay.
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- 2010
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15. Preparation of cross-linked chitosan/glyoxal molecularly imprinted resin for efficient chiral resolution of aspartic acid isomers
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Mohamed Monier, A.A. Sarhan, D.M. Ayad, and Yen Wei
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Environmental Engineering ,Aqueous solution ,endocrine system diseases ,Chemistry ,Biomedical Engineering ,nutritional and metabolic diseases ,Bioengineering ,Chiral resolution ,Solvent ,chemistry.chemical_compound ,Adsorption ,Aspartic acid ,Organic chemistry ,Racemic mixture ,Glyoxal ,Molecular imprinting ,hormones, hormone substitutes, and hormone antagonists ,Biotechnology ,Nuclear chemistry - Abstract
An enantioselective l -aspartic acid imprinted chitosan (LAIC) was prepared by cross-linking of chitosan by glyoxal cross-linker, in the presence of l -aspartic acid as an imprinted template molecule and 1% acetic acid solution as a solvent. Non-imprinted cross-linked chitosan (NIC) as control was also prepared by the same procedure in the absence of template molecules. The surface morphology of both LAIC and NIC was examined by scanning electron microscope (SEM). LAIC particles were applied to determine the optimum operational condition for l -aspartic acid separation from dilute aqueous solution. In adsorption step, optimum pH and retention time were 5 and 90 min, while corresponding values in extraction step were 2 and 50 min, respectively. Also, the adsorption isotherms indicated that the maximum adsorption capacities of l- and d -aspartic acid on LAIC were 48 ± 0.7 and 27 ± 1 mg g−1, respectively, while in the case of NIC, both l - and d -aspartic acid present the same maximum adsorption capacity 9 ± 0.8 mg g−1, which confirms that the molecular imprinting technique creates an enantioselectivity of LAIC toward l -aspartic acid. In addition, chiral resolution of l , d -aspartic acid racemic mixture was carried out using column of LAIC.
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- 2010
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16. Ionotropically cross-linked pH-sensitive IPN hydrogel matrices as potential carriers for intestine-specific oral delivery of protein drugs
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Ahmed Salama, Ibrahim M. El-Sherbiny, and A.A. Sarhan
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Time Factors ,Administration, Oral ,Pharmaceutical Science ,Peptide ,Divalent ,Drug Delivery Systems ,Differential scanning calorimetry ,Intestine, Small ,Drug Discovery ,Polymer chemistry ,medicine ,Bovine serum albumin ,Pharmacology ,chemistry.chemical_classification ,Drug Carriers ,Gastric Juice ,Chromatography ,Intestinal Secretions ,biology ,Organic Chemistry ,technology, industry, and agriculture ,Hydrogels ,Serum Albumin, Bovine ,Hydrogen-Ion Concentration ,Grafting ,Carboxymethyl cellulose ,Cross-Linking Reagents ,Acrylates ,chemistry ,Carboxymethylcellulose Sodium ,Delayed-Action Preparations ,Self-healing hydrogels ,Microscopy, Electron, Scanning ,biology.protein ,Calcium ,Swelling ,medicine.symptom ,medicine.drug - Abstract
Background: The oral delivery of proteins and peptide drugs is considered a major challenge. These types of therapeutics are readily degraded, if taken orally, due to the harsh high acidity of stomach and enzymatic attack in the upper small intestinal tract. Methods: Water-soluble copolymers of sodium acrylate (AAs) grafted onto carboxymethyl cellulose (CMC) were prepared and characterized using Fourier transform spectroscopy, differential scanning calorimetry, and X-ray diffraction. The obtained graft copolymers were then used in a combination with sodium alginate to develop a new series of pH-sensitive interpenetrating polymeric network (IPN) hydrogels through ionotropic gelation with divalent ions (Ca 2+ ). Morphology of the developed hydrogels was investigated using SEM. Swelling characteristics, at distinct compositions, were also studied at 37°C in two consecutive buffer solutions of pH 2.1 and 7.4 (similar to that of gastric and intestinal fluids, respectively). The release profiles of bovine serum albumin, as a model protein, from test IPN hydrogel films were studied in simulated gastric and intestinal fluids. In addition, the drug release process was confirmed by means of SEM. Results: Swelling studies of the developed IPN hydrogels at different pH values confirmed their pH-sensitive nature. The equilibrium swelling extents of the hydrogels were found to be dependent on the grafting yield of CMC/AAs graft copolymer. The IPN hydrogels attained equilibrium swelling percentages in the range 445–740%. In addition, the amount of bovine serum albumin released within 2 hours in pH 2.1 was relatively low (less than 18.1%). This amount increased up to 68% after 8 hours in pH 7.4. Conclusions: From the obtained preliminary data, it seems that the IPN hydrogels developed in this contribution can be tailored to act as good potential carriers for oral delivery of protein drugs. These hydrogels showed a promising protection of protein drugs from the harsh acidity of stomach and, at the same time, they conferred sustained drug release in the intestinal fluid.
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- 2010
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17. Adsorption of Cu(II), Hg(II), and Ni(II) ions by modified natural wool chelating fibers
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A.A. Sarhan, Mohamed Monier, and D.M. Ayad
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Environmental Engineering ,Polymers ,Health, Toxicology and Mutagenesis ,Metal ions in aqueous solution ,Inorganic chemistry ,Hydrazone ,Hydrazide ,Metal ,chemistry.chemical_compound ,Adsorption ,Nickel ,Animals ,Environmental Chemistry ,Chelation ,Waste Management and Disposal ,Chelating Agents ,chemistry.chemical_classification ,Chemistry ,Wool ,Hydrazones ,Mercury ,Pollution ,Acrylates ,Polymerization ,visual_art ,visual_art.visual_art_medium ,Ethyl acrylate ,Copper ,Nuclear chemistry - Abstract
The graft copolymerization of ethyl acrylate (EA) onto natural wool fibers initiated by potassium persulphate and Mohr's salt redox initiator system in limited aqueous medium was carried out in heterogeneous media. Ester groups of the grafted copolymers were partially converted into hydrazide function groups followed by hydrazone formation through reaction with isatin. Also the application of the modified fibers for metal ion uptake was studied using Cu(II), Hg(II) and Ni(II). The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction.
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- 2010
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18. Evaluation of the potential of polymeric carriers based on photo-crosslinkable chitosan in the formulation of lipase from Candida rugosa immobilization
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A.A. Sarhan, M. Monier, and Yen Wei
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chemistry.chemical_classification ,Chromatography ,biology ,Process Chemistry and Technology ,technology, industry, and agriculture ,Triacylglycerol lipase ,Bioengineering ,Polymer ,Biochemistry ,Catalysis ,Candida rugosa ,Chitosan ,chemistry.chemical_compound ,Enzyme ,chemistry ,biology.protein ,Moiety ,Fourier transform infrared spectroscopy ,Lipase - Abstract
Using an EDC/NHS conjugation method, chitosan was chemically modified to incorporate a photosensitive α-cyano-4-hydroxycinnamic acid moiety with various degrees of substitutions. The chitosan α-cyano-4-hydroxycinnamate was fully characterized by FTIR, 1 H NMR and UV–vis spectra. Lipase from Candida rugosa was entrapped in the modified photo-crosslinkable chitosan membranes. Crosslinking was carried out by irradiation in the ultraviolet region. The activities of free and immobilized lipase have been studied. The efficiency of the immobilization was evaluated by examining the relative enzymatic activity of free enzyme before and after the immobilization of lipase. The obtained values were found to reach 98.6%. The results showed that the optimum temperature of immobilized lipase was 40 °C, which was identical to that of the free enzyme, and the immobilized lipase exhibited a higher relative activity than that of free lipase over 40 °C. The optimal pH for immobilized lipase was 8.0, which was higher than that of the free lipase (pH 7.5), and the immobilization resulted in stabilization of enzyme over a broader pH range. The kinetic constant value ( K m ) of immobilized lipase was 1.332 mg ml −1 (1.50 × 10 −3 M), which was higher than that of free lipase. On the other hand, the activity of immobilized lipase decreased slowly against time when compared to that of the free lipase, and could retain 75.5% residual activity after 6 consecutive cycles.
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- 2010
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19. Immobilization of horseradish peroxidase on modified chitosan beads
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Mohamed Monier, D.M. Ayad, A.A. Sarhan, and Yen Wei
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Surface Properties ,Potassium ,Kinetics ,Acrylic Resins ,chemistry.chemical_element ,Biochemistry ,Horseradish peroxidase ,Redox ,Chitosan ,chemistry.chemical_compound ,Structural Biology ,Enzyme Stability ,Spectroscopy, Fourier Transform Infrared ,Copolymer ,Fourier transform infrared spectroscopy ,Molecular Biology ,Horseradish Peroxidase ,Chromatography ,biology ,Temperature ,food and beverages ,General Medicine ,Hydrogen-Ion Concentration ,Enzymes, Immobilized ,Grafting ,Microspheres ,chemistry ,Biocatalysis ,Microscopy, Electron, Scanning ,biology.protein - Abstract
A method has been developed to immobilize horseradish peroxidase (HRP) on modified chitosan beads by means of graft copolymerization of polyethylacrylate in presence of potassium persulphate and Mohr's salt redox initiator. The activity of free and immobilized HRP was studied. FTIR spectroscopy and scanning electron microscopy were used to characterize HRP immobilization. The efficiency of the immobilization was investigated by examining the relative enzymatic activity of free enzyme before and after the HRP immobilization. The obtained values were found to reach 98.4%. The results show that the optimum temperature of immobilized HRP was 45 degrees C, which was identical to that of free enzyme, and the immobilized HRP exhibited a higher relative activity than that of free HRP over 45 degrees C. The optimal pH for immobilized HRP was 10, which was higher than that of the free HRP (pH 9.0), and the immobilization resulted in stabilization of enzyme over a broader pH range. The apparent kinetic constant value (K(m)) of immobilized HRP was 3.784 mmol ml(-1), which was higher than that of free HRP. On the other hand, the activity of immobilized HRP decreased slowly against time when compared to that of the free HRP, and could retain 65.8% residual activity after 6 consecutive cycles.
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- 2010
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20. Synthesis and characterization of photo-crosslinkable hydrogel membranes based on modified chitosan
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A.A. Sarhan, Yen Wei, D.M. Ayad, and Mohamed Monier
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Thermogravimetric analysis ,Polymers and Plastics ,Chemistry ,Organic Chemistry ,technology, industry, and agriculture ,Chemical modification ,macromolecular substances ,Chitosan ,chemistry.chemical_compound ,Membrane ,Monomer ,Chemical engineering ,Polymer chemistry ,Materials Chemistry ,medicine ,Thermal stability ,Fourier transform infrared spectroscopy ,Swelling ,medicine.symptom - Abstract
In order to develop a non toxic and biocompatible hydrogel system with potential ability in biotechnology, modified photo-crosslinkable hydrogel membranes based on chitosan were prepared. Using an EDC/NHS conjugation method, chitosan was chemically modified to incorporate a photosensitive α-cyano-4-hydroxycinnamic acid moiety with various degrees of substitutions. Fourier transform infrared spectra (FTIR), proton nuclear magnetic resonance (1H NMR) and ultraviolet–visible light spectra (UV–vis) were used for structural characterization of modified chitosan, The obtained membranes were crosslinked by irradiation in the ultraviolet region, where the photosensitive monomers showed maximum sensitivity. The prepared photo-crosslinked hydrogel membranes were investigated by thermal gravimetric analysis (TGA) and wide angle X-ray diffraction (WAXD). The swelling behaviors were investigated in terms of pH, time of swelling, and degree of substitution. Also, mechanical properties of the different photo-crosslinked hydrogel membranes were studied in both dry and wet conditions.
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- 2010
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21. Immobilization of Candida rugosa lipase on modified natural wool fibers
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A.M.A. El-Sokkary, A.A. Sarhan, and Mohamed Monier
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Chromatography ,Polymers and Plastics ,Immobilized enzyme ,biology ,Chemistry ,General Chemical Engineering ,Triacylglycerol lipase ,General Chemistry ,Grafting ,Biochemistry ,Redox ,Candida rugosa ,Covalent bond ,Materials Chemistry ,biology.protein ,Environmental Chemistry ,Lipase ,Bradford protein assay - Abstract
A method has been developed to immobilize lipase from Candida rugosa on modified natural wool fibers by means of graft copolymerization of poly ethylacrylate in presence of potassium persulphate and Mohr’s salt redox initiator. The activities of free and immobilized lipase have been studied. FTIR spectroscopy, scanning electron microscopy, and the Bradford method were used to characterize lipase immobilization. The efficiency of the immobilization was evaluated by examining the relative enzymatic activity of free enzyme before and after the immobilization of lipase. The results showed that the optimum temperature of immobilized lipase was 40 °C, which was identical to that of the free enzyme, and the immobilized lipase exhibited a higher relative activity than that of free lipase over 40 °C. The optimal pH for immobilized lipase was 8.0, which was higher than that of the free lipase (pH 7.5), and the immobilization resulted in stabilization of enzyme over a broader pH range. The kinetic constant value (km) of immobilized lipase was higher than that of the free lipase. However, the thermal and operational stabilities of immobilized lipase have been improved greatly.
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- 2010
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22. Harmonic Scalpel® compared with bipolar electro-cautery hemorrhoidectomy: A randomized controlled trial
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A.A. Sarhan, A.A. Abo-hashem, and A.M. Aly
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Adult ,Male ,Bipolar electro-cautery Hemorrhoidectomy ,medicine.medical_specialty ,medicine.medical_treatment ,Analgesic ,Hemorrhoids ,Electrocoagulation ,law.invention ,Postoperative Complications ,Randomized controlled trial ,law ,Harmonic scalpel ,Humans ,Medicine ,Single-Blind Method ,Ultrasonics ,Open and closed hemorrhoidectomy ,Harmonic Scalpel ,Pain, Postoperative ,business.industry ,General Medicine ,Middle Aged ,Surgical Instruments ,Ablation ,medicine.disease ,Surgery ,surgical procedures, operative ,Anesthesia ,Female ,Surgical excision ,business ,Tissue Dissection - Abstract
Introduction Surgical excision using Harmonic Scalpel ® is a modern technique used for ablation of symptomatic third degree and all fourth-degree hemorrhoids. Compared with electrocautery, Harmonic Scalpel ® causes minimal lateral thermal injury during tissue dissection. The resulting mucosal defect is then either left open or sutured (closed) depending on surgeon preference. The aim of this work was to evaluate the value of using Harmonic Scalpel ® in reducing incidence of postoperative complications following Hemorrhoidectomy. Patients & Methods This is a single-blind randomized controlled trial done at Zagazig University hospital during the period from July 2007 to December 2008. Patients underwent surgical excision of complex grade III or grade IV hemorrhoids. They were divided into two groups: (A) Harmonic Scalpel ® Hemorrhoidectomy group and (B) Bipolar Electro-cautery Hemorrhoidectomy group. Pain levels scoring and postoperative complications were analyzed. Results Postoperative pain in Group (A) was significantly less with less analgesic requirement. There was no significant difference between both groups regarding other postoperative complications. Conclusion This study demonstrates significantly reduced postoperative pain after Harmonic Scalpel ® Hemorrhoidectomy compared with bipolar electro-cautery Hemorrhoidectomy. Most likely, this result came from the avoidance of excessive lateral thermal injury caused by bipolar electrocautery.
- Published
- 2010
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23. Phase transfer catalyzed heterogeneous N-deacetylation of chitin in alkaline solution
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D.M. Ayad, D. S. Badawy, A.A. Sarhan, and Mohamed Monier
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Polymers and Plastics ,Chemistry ,Stereochemistry ,General Chemical Engineering ,Kinetics ,Aqueous two-phase system ,General Chemistry ,Activation energy ,Atmospheric temperature range ,Biochemistry ,Catalysis ,Reaction rate constant ,Phase (matter) ,Materials Chemistry ,Environmental Chemistry ,Phase-transfer catalyst ,Nuclear chemistry - Abstract
Chitin was extracted from shrimp shell waste and its heterogeneous alkaline deacetylation under phase transfer catalysis (PTC) condition was performed. The reaction followed the first-order kinetics during an initial period. The influences of type and concentration of phase transfer catalyst, type of organic solvent, alkaline concentration, temperature, time and volume of organic phase to the volume of aqueous phase ratio on the N -deacetylation were investigated. The degree of deacetylation (DD) increased mainly with increasing temperature, catalyst concentration and time. In the temperature range of 30–100 °C, the apparent rate constant and the activation energy of the reaction were evaluated in presence and in absence of PTC condition.
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- 2009
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24. The Distribution of Glutathione and Glutathione S-transferase Activity in the Organs of Dhub (The Agamid Lizard; Uromastyx aegyptius)
- Author
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Mohammed A.A. Sarhan and Ahmed Al-Qahtani
- Subjects
chemistry.chemical_compound ,chemistry ,Biochemistry ,Molecular Medicine ,Distribution (pharmacology) ,Agamid lizard ,Cell Biology ,Glutathione ,Biology ,biology.organism_classification ,Uromastyx ,Glutathione S-transferase activity - Published
- 2007
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25. Adsorption Characteristics of Copper (II) Ions from Aqueous Solution onto Ionic Cross-linked Pva/P(Aam-Nipaam) Core-shell Nanogels
- Author
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A.A. Sarhan, Kamal Razaq, and Magda A. Akl
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Vinyl alcohol ,Thermogravimetric analysis ,Materials science ,Aqueous solution ,Metal ions in aqueous solution ,Biomedical Engineering ,Pharmaceutical Science ,Medicine (miscellaneous) ,Bioengineering ,chemistry.chemical_compound ,Adsorption ,chemistry ,Polymer chemistry ,Freundlich equation ,Fourier transform infrared spectroscopy ,Nuclear chemistry ,Nanogel - Abstract
Core-shell nanogels adsorbent were investigated for copper (II) removal from aqueous solution, consisting of poly(vinyl alcohol) (PVA) core and poly(acrylamide- N-isopropylacrylamide/) p(AAm-NIPAm) shell particles. Various factors affecting the adsorption capacity, such as swelling, pH, time, initial ion concentration, and different metal ions on the metal ion binding capacity for nanogel, was also tested. The selectivity of the nanogels toward the different metal ions tested was Cu2+> Ni2+ > Pb2+. The results show that the adsorption of nanogels mainly depends on pH, and the maximum adsorption was obtained at a pH of 6.0. The adsorption capacity of Cu+2 was 126 mg/g obtained under simple and fast experimental conditions, the effect of different mole ratios of p(AAm-NIPAm) shells thickness were synthesized, to determine the maximum metal uptake. The core-shell nanogels were characterized by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and transmission electron microscope (TEM). It was found that adsorbed Cu+2 ions on PVA/p(AAm-NIPAm) nanogels can be effectively desorbed by acid stripping with 0.1 mol/L HCl resulted in 96% Cu+2 recovery for the nanogels; this shows the ability of the nanogels to be reused, upon drying between treatments. The nanogels adsorbent can be regenerated after releasing of Cu+2 and reused three times effectively. All the experimental result exhibited good matches with the Freundlich isotherm and followed pseudo-second-order kinetics. The mechanism of adsorption of Cu+2 onto PVA/p(AAm-NIPAm) nanogels is proposed.
- Published
- 2015
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26. Synthesis and Evaluation of 2-Acrylamido-2-Methyl-1- Propane Sulfonic Acid Based on Core-Shell Nanogels for Preconcentration of Fe (III) Ions from Aqueous Solutions and their Determination in Real Water Samples
- Author
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Magda A. Akl, Kameel S Razak, and A.A. Sarhan
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chemistry.chemical_classification ,Vinyl alcohol ,Aqueous solution ,Materials science ,Langmuir adsorption model ,02 engineering and technology ,Sulfonic acid ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,symbols.namesake ,chemistry.chemical_compound ,Adsorption ,chemistry ,Ionic strength ,Desorption ,Polymer chemistry ,symbols ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Nuclear chemistry - Abstract
Synthesis and Evaluation of 2-Acrylamido-2-Methyl-1- Propane Sulfonic Acid Based on Core-Shell Nanogels for Preconcentration of Fe (III) Ions from Aqueous Solutions and their Determination in Real Water Samples In the present study, poly(2-acrylamido-2-methyl-1-propanesulfonic acid -co-N-isopropylacrylamide) hydrogels, were synthesized by free- radical crosslinking solution polymerization with different ratios of monomers to form colloidal hydrogels shell around poly(vinyl alcohol) core through epichlorohydrine, in order to obtain well-define PVA(AMPS-NIPAm) core/shell nanogels with diameter nearly 30 nm. The prepared nanogels were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). These Nanogels were used effectively for removal of Fe(III) ions from aqueous solutions. The factors affecting adsorption such as pH, contact time, initial concentration, temperature, ionic strength, desorption, interfering ions, and analytical application for real water samples were succefully investigated. The maximum capacity of Fe(III) ions was 320, 202 and 98 (mg/g) for PVA/p(90AMPS-10NIPAm), PVA/ p(50AMPS-50NIPAm) and PVA/p(10AMPS-90NIPAm), (wt.:wt. %), respectively. The adsorption isotherms and kinetics were determined; the equilibrium data matched well with the Langmuir model. The pseudo second-order model described the adsorption process better than the pseudo first-order model. Thermodynamic parameters revealed that a spontaneous and exothermic nature is identified in all cases of adsorption process.
- Published
- 2015
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27. Phase transfer catalyzed reactions of crosslinked chloromethylated polystyrene with vanillin
- Author
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Ashraf A. El-Shehawy, A.A. Sarhan, and Magdy Y. Abdelaal
- Subjects
chemistry.chemical_classification ,Cyanoacetamide ,Polymers and Plastics ,General Chemical Engineering ,Vanillin ,General Chemistry ,Condensation reaction ,Biochemistry ,Aldehyde ,Catalysis ,Solvent ,chemistry.chemical_compound ,chemistry ,Polymer chemistry ,Materials Chemistry ,Environmental Chemistry ,Organic chemistry ,Polystyrene ,Malononitrile - Abstract
Chloromethylated polystyrene was reacted with vanillin under phase transfer catalyzed conditions. This reaction was performed under different conditions, including variations of the phase transfer catalysts, the reaction solvent, the type of base, the reaction time and temperature. In addition, the effect of the reaction technique (i.e., solid–liquid–liquid and solid–liquid–solid systems) on the reaction conversion was studied. Polymer-supported vanillin was evaluated for its utilization in polymer analogue conversions by performing condensation reactions of the aldehyde functionality with malononitrile, ethyl cyanoacetate, cyanoacetamide, cyanothioacetamide, 2-aminophenol, hydrazine hydrate and hydroxylamine hydrochloride. In all cases, the reactions were followed up by means of FTIR spectroscopic analysis.
- Published
- 2002
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28. Identification of Acinetobacter clinical isolates by polymerase chain reaction analysis of 16S-23S ribosomal ribonucleic acid internal transcribed spacer
- Author
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M N Mohamed, Mohammed A.A. Sarhan, Waleed O Haimour, T H Taha, Amani A Osman, and Nazar M Abdalla
- Subjects
Acinetobacter baumannii ,Microbiology (medical) ,Lineage (evolution) ,Ribosomal Intergenic Spacer analysis ,lcsh:QR1-502 ,Polymerase Chain Reaction ,lcsh:Microbiology ,Microbiology ,law.invention ,Intergenic region ,law ,RNA, Ribosomal, 16S ,DNA, Ribosomal Spacer ,Internal transcribed spacer ,Assir region ,Polymerase chain reaction ,Phylogeny ,biology ,Acinetobacter ,Ribosomal RNA ,biology.organism_classification ,Bacterial Typing Techniques ,RNA, Ribosomal, 23S ,16S-23S ribosomal ribonucleic acid - Abstract
Background: The genus Acinetobacter is a diverse group of Gram-negative bacteria involve at least 33 species using the molecular methods. Although the genus Acinetobacter comprises a number of definite bacterial species, some of these species are of clinical importance. Therefore, it is of vital importance to use a method which is able to reliably and efficiently differentiate the numerous Acinetobacter species. Objectives: This study aims to identify Acinetobacter of clinical isolates from Assir region to the species level by 16S-23S intergenic spacers internal transcribed spacer (ITS) of ribosomal ribonucleic acid (rRNA). Materials and Methods: Deoxyribonucleic acid extraction, polymerase chain reaction amplification of 16S-23S intergenic spacer sequences (ITS) was performed using the bacterium-specific universal primers. Results: Based on the 16S-23S intergenic spacers (ITS) of rRNA sequences, all isolates tested were identified as Acinetobacter baumannii. The isolates shared a common ancestral lineage with the prototypes A. baumannii U60279 and U60280 with 99% sequence similarities. Conclusion: These findings confirmed 16S-23S rRNA ITS for the identification of A. baumannii of different genotypes among patients.
- Published
- 2014
29. Reaction of crosslinked chloromethylated polystyrene with 4-hydroxybenzaldehyde under phase transfer-catalyzed conditions
- Author
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E.H. Abdel-Latiff, M.M. Ali, A.A. Sarhan, and Magdy Y. Abdelaal
- Subjects
chemistry.chemical_classification ,Polymers and Plastics ,Chemistry ,Organic Chemistry ,Aldehyde ,Catalysis ,chemistry.chemical_compound ,4-Hydroxybenzaldehyde ,Nucleophile ,Reagent ,Polymer chemistry ,Materials Chemistry ,Nucleophilic substitution ,Polystyrene ,Chemoselectivity - Abstract
The present work studied factors which may affect phase transfer-catalyzed (PTC) nucleophilic displacement reactions, including chloromethylated polystyrene as polymer-supported alkylating agent and 4-hydroxybenzaldehyde as an O-nucleophilic reagent in presence of representatives for phase transfer catalysts. Some polymer-analogue conversions using the resulting polymer-supported aldehyde have been carried out.
- Published
- 1999
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30. Antimicrobial susceptibility pattern in nosocomial infections caused by Acinetobacter species in Asir Region, Saudi Arabia
- Author
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Amani A Osman, Mohammed A.A. Sarhan, Mohammed N Mohammed, Waleed O Haimour, Abdalla M Al-Ghtani, Nazar M Abdalla, and Eyhab M Zyad
- Subjects
Imipenem ,Cross Infection ,Time Factors ,Acinetobacter ,business.industry ,medicine.drug_class ,Antibiotics ,Saudi Arabia ,Microbial Sensitivity Tests ,Antimicrobial ,Meropenem ,Microbiology ,Anti-Bacterial Agents ,Acinetobacter calcoaceticus/baumannii Complex ,Nitrofurantoin ,Ticarcillin ,Drug Resistance, Multiple, Bacterial ,Colistin ,medicine ,Humans ,Prospective Studies ,business ,Agronomy and Crop Science ,medicine.drug ,Acinetobacter Infections - Abstract
This study aimed at evaluating the sensitivity of antibiotics towards nosocomial infections caused by Acinetobacter species. The study took place during the period Dec. 2011- Dec. 2012 at Assir Central Hospital in collaboration with the department of microbiology, college of medicine, King Khalid University, Abha. A prospective study involving 150 patients presented with nosocomial infections due to Acinetobacter species detected by bacteriological tests; direct microscopy, culture in blood agar media, fermentation test in MacConkey media and MIC (minimum inhibitory concentration) for antibiotics sensitivity using Muller Hinton media and Chemical test using API 20. A 150 nosocomial infections in this study showed gram-negative coccobacilli, non motile, glucose-negative fermentor and oxidase negative. All isolates showed 100% sensitivity to: Imipramine, Meropenem, Colistin. From the rest of tested antibiotics the higher resistant ones were; Nitrofurantoin 87% and Cefoxitin 85%. The least resistant antibiotics; Imipenem 3% and Ticarcillin 7%. While variable resistance in the rest of tested antimicrobials. A 47 patients (31.3%) have used antibiotics prior to this study. The high rate of usage occurred in elder patients. The frequency of Acinetobacter calcoaceticus baumannii complex multi-drugs resistance ABCMDR is rising including almost all commonly used antibiotics. Only few antibiotics exert 100% sensitivity towards these bacteria.
- Published
- 2014
31. Studies on the alkylation of polymer-supported ambident anion derived from indane-1,3-dione
- Author
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Magdy Y. Abdelaal, A.A. Sarhan, M.R. Ibrahim, and E.M. Afsah
- Subjects
Diketone ,Reaction mechanism ,Polymers and Plastics ,Dibenzoylmethane ,Chemistry ,General Chemical Engineering ,Indane ,Regioselectivity ,General Chemistry ,Alkylation ,Biochemistry ,Medicinal chemistry ,Ion ,chemistry.chemical_compound ,Materials Chemistry ,Environmental Chemistry ,Organic chemistry ,Solvent effects - Abstract
The behavior of polymer-supported ambident anions derived from indane-1,3-dione towards alkylation under various conditions has been studied. Particularly, factors that may affect the yields of isolated products and their compositions have been considered. Almost exclusively the di- C -alkylation product could be isolated after relatively long reaction time. This unusual tendency toward di- C -alkylation is extensively discussed on the basis of the effect of reduced reaction time on the composition of resulting products in addition to a comparative study of mono- C -versus di- C -alkylation in indane-1,3-dione with the acyclic analogous dibenzoylmethane.
- Published
- 1997
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32. Homogeneous Photoinouced Graft Copolymerization of Acrylamide onto Abs Copolymers in the Presence of 4-Acetyldiphenyl as Photosensitizer.: 1. Influence of Butadiene Content in Abs Copolymers
- Author
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M.M. Ali, E. A. Abdel-Razik, A.A. Sarhan, and Magdy Y. Abdelaal
- Subjects
Materials science ,Polymers and Plastics ,General Chemical Engineering ,Materials Science (miscellaneous) ,Infrared spectroscopy ,Concentration effect ,Substrate (chemistry) ,Grafting ,chemistry.chemical_compound ,surgical procedures, operative ,Monomer ,chemistry ,Acrylamide ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Photosensitizer - Abstract
Photoinduced graft copolymerization of acrylamide (AM) onto two types of acrylonitrile-butadiene-styrene (ABS) copolymers was extensively investigated in homogeneous media. The grafting process was conducted in chloroform in presence of 4-acetyldi-phenyl (4-AD). Ultraviolet (UV) irradiation was used in the range of 310 to 460 nm. The UV spectrum of 4-AD has sλmax at 285 nm and shows n-π∗ transitions. The grafting parameters, such as weight conversion, grafting percentage, and grafting efficiency, were determined as a function of the irradiation time and the concentrations of monomer, initiator, and substrate. A reverse effect was observed between the grafting percentage and the butadiene content in ABS copolymers. The rates of graft copolymerization of AM onto the two types of ABS copolymers were determined. A Trommsdorf effect was observed in certain systems. The IR spectrum of ABS-g-AM graft copolymer shows the appearance of a new peak at 1685 cm-1 that declares the presence of poly-acrylamide-...
- Published
- 1996
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33. Homogeneous Photoinduced Graft Copolymerization of 4-Vinyl Pyridine onto Ethyl Cellulose. 1. Influence of Biacetal and Acetonaphthone Derivatives
- Author
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A.A. Sarhan, N. M. Abdel-Salam, E. A. Abdel-Razik, and E. M. Abdel-Bary
- Subjects
Materials science ,Polymers and Plastics ,General Chemical Engineering ,Materials Science (miscellaneous) ,Infrared spectroscopy ,Grafting ,Absorbance ,chemistry.chemical_compound ,Monomer ,chemistry ,Ethyl cellulose ,Polymer chemistry ,Pyridine ,Materials Chemistry ,Copolymer ,Photosensitizer - Abstract
Homogeneous photoinduced graft copolymerization of 4-vinyl pyridine (4-VP) onto ethyl cellulose (EC) in the presence of three photosensitizers such as 1-acetonaphthone (1-An), 2-acetonaph-thone (2-An), and biacetal (Bi) in benzene solution was extensively investigated. Ultraviolet (UV) irradiation in the range 310 to 460 nm was used. The U V spectra of the mentioned photosensitizers showed n-π∗ transitions. Grafting parameters such as grafting percentage (GP) and grafting efficiency (GE) were determined as functions of the irradiation time and the concentrations of monomer, substrate, and initiator. The IR spectrum of the EC-g-4-VP copolymer shows the appearance of new peaks between 1600 and 1690 cm-1 indicating the presence of poly-4-vinyl pyridine (p-4-VP) grafted chains. The rate of copolymerization of 4-VP onto EC in the presence of 1-An, 2-An, and Bi was determined as 0.98% min-1, 0.88% min-1 and 0.042% min-1, respectively. A good correlation was observed between the change in absorbance at ...
- Published
- 1996
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34. Patient-derived hepatitis C virus and JFH-1 clones differ in their ability to infect human hepatoma cells and lymphocytes
- Author
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Annie Y. Chen, Rodney S. Russell, Tomasz I. Michalak, and Mohammed A.A. Sarhan
- Subjects
Adult ,Male ,Carcinoma, Hepatocellular ,DNA, Complementary ,Genotype ,Hepatitis C virus ,T-Lymphocytes ,Cell ,Clone (cell biology) ,Hepacivirus ,Biology ,medicine.disease_cause ,Virus Replication ,Jurkat cells ,Peripheral blood mononuclear cell ,Virus ,Immune system ,Virology ,Cell Line, Tumor ,medicine ,Humans ,Receptor ,Reverse Transcriptase Polymerase Chain Reaction ,Liver Neoplasms ,virus diseases ,Hepatitis C, Chronic ,Middle Aged ,digestive system diseases ,Viral Tropism ,medicine.anatomical_structure ,RNA, Viral ,Signal Transduction - Abstract
Hepatitis C virus (HCV) is a hepatotropic virus that also infects cells of the immune system. HCV clones cultivated in human hepatoma Huh-7.5 cells have significantly advanced our understanding of HCV replication and candidate hepatocyte receptors. However, naturally occurring patient-derived HCV, in contrast to the HCV JFH-1 clone, is unable to infect Huh-7.5 cells, while it can replicate in human primary T-cells and selected T-cell lines. To better understand this incongruity, we examined the susceptibility of primary T-cells, PBMCs and T-cell lines to infection with patient-derived HCV, the classical HCV JFH-1 and a cell culture-adapted JFH1T known to be highly infectious to Huh-7.5 cells. We also tested whether Huh-7.5 cells are prone to virus readily infecting T-lymphocytes. The results revealed that while primary T-cells and Molt4 and Jurkat T-cell lines were susceptible to patient-derived HCV, they were resistant to infection with either JFH1T or JFH-1. However, the JFH1T clone interacted more firmly, although non-productively, with the cells than JFH-1. Further, Huh-7.5 cells robustly supported replication of JFH1T but not patient-derived, wild-type virus, despite using highly sensitive detection assays. In conclusion, JFH-1 and JFH1T clones were unable to establish productive infection in human primary T-cells, PBMCs and T-cell lines known to be prone to infection by patient-derived HCV, while Huh-7.5 cells were resistant to infection with naturally occurring virus infecting immune cells. The data showed that the ability to infect lymphocytes is a characteristic of native virus but not laboratory HCV clones.
- Published
- 2012
35. Hepatitis C virus infection of human T lymphocytes is mediated by CD5
- Author
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Mohammed A.A. Sarhan, Tram N. Q. Pham, Annie Y. Chen, and Tomasz I. Michalak
- Subjects
Hepatitis C virus ,T cell ,T-Lymphocytes ,Immunology ,Hepacivirus ,medicine.disease_cause ,CD5 Antigens ,Microbiology ,Virus ,Cell Line ,Small hairpin RNA ,Immune system ,Virology ,medicine ,Humans ,biology ,virus diseases ,T lymphocyte ,Hepatitis C ,digestive system diseases ,Virus-Cell Interactions ,NS2-3 protease ,medicine.anatomical_structure ,Insect Science ,biology.protein ,Antibody - Abstract
Hepatitis C virus (HCV) is one of the main causes of chronic liver disease. Although infection of hepatocytes is mainly responsible for manifestations of hepatitis C, the virus also invades the immune system by a yet-to-be-identified mechanism. Using human T cell lines and primary T lymphocytes as targets and patient-derived HCV as inocula, we aimed to identify how HCV gains entry into these cells. HCV replication was determined by detection of the HCV RNA replicative (negative) strand and viral proteins, while specific antibodies, knocking down gene expression and making otherwise-resistant cells prone to HCV, were employed to identify a receptor molecule determining T lymphocyte permissiveness to HCV infection. The results revealed that T cell susceptibility to HCV requires CD5, a lymphocyte-specific glycoprotein belonging to the scavenger receptor cysteine-rich family. Blocking of T cell CD5 with antibody or silencing with specific short hairpin RNA (shRNA) decreased cell susceptibility to HCV, while increasing CD5 expression by mitogen stimulation had the opposite effect. Moreover, transfection of naturally CD5-deficient HEK-293 fibroblasts with CD5 facilitated infection of these otherwise HCV-resistant cells. In contrast to T cells, hepatocytes do not express CD5. The data revealed that CD5 is a molecule important for HCV entry into human T lymphocytes. This finding provides direct insight into the mechanism of HCV lymphotropism and defines a target for potential interventions against HCV propagating in this extrahepatic compartment.
- Published
- 2012
36. [Untitled]
- Author
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E. M. Abdel-Bary, Magdy Y. Abdelaal, A.A. Sarhan, and G. A. Koßmehl
- Subjects
Chemistry ,Comonomer ,Methacrylate ,chemistry.chemical_compound ,Methacrylic acid ,Acrylamide ,Polymer chemistry ,Self-healing hydrogels ,medicine ,General Materials Science ,Swelling ,medicine.symptom ,Chemical composition ,Acrylic acid - Abstract
Some hydrogels of different chemical composition were synthesized using 2-hydroxyethyl methacrylate, methacrylic acid, acrylic acid, and acrylamide in different ratios and crosslinked by ethylene dimethacrylate. Effects of the copolymer composition as well as the type of monomers on some hydrogel characteristics were evaluated. Some characteristic properties, namely soluble fraction percentage, swelling degree, solution uptake, and salt uptake were found to be markedly affected by the hydrogel composition. Hydrogele verschiedener Zusammensetzung wurden aus Hydroxyethylmethacrylat, Methacrylsaaure, Acrylsaaure und Acrylsaaureamid und dem Vernetzer Ethylendimethacrylat in unterschiedlichen Molverhaaltnissen hergestellt. Der Einflus der Zusammensetzung der Copolymeren und die Struktur der Monomeren bestimmen die typischen Eigenschaften der einzelnen Hydro9gelproben. Es wurde gefunden, das besonders der laosliche Anteil, der Quellungsgrad und die Laosungs-und Salzaufnahme durch die Struktur der einzelnen Hydrogelproben bestimmt wird.
- Published
- 1994
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37. ChemInform Abstract: Enantioselective Synthesis of Homoallylamines by Nucleophilic Addition of Chirally Modified Allylboron Reagents to Imines
- Author
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Katsuhiro Watanabe, Ashraf A. El-Shehawy, A.A. Sarhan, Koichi Ito, and Shinichi Itsuno
- Subjects
Addition reaction ,Nucleophilic addition ,Chemistry ,Reagent ,Enantioselective synthesis ,General Medicine ,Combinatorial chemistry - Published
- 2010
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38. Evaluation of the potential of polymeric carriers based on chitosan-grafted-polyacrylonitrile in the formulation of drug delivery systems
- Author
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D.M. Ayad, A.A. Sarhan, Mohamed Monier, and D. S. Badawy
- Subjects
Thermogravimetric analysis ,Materials science ,Polymers and Plastics ,Radical polymerization ,technology, industry, and agriculture ,Polyacrylonitrile ,macromolecular substances ,General Chemistry ,Surfaces, Coatings and Films ,chemistry.chemical_compound ,chemistry ,Drug delivery ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Acrylonitrile ,Fourier transform infrared spectroscopy ,Drug carrier - Abstract
Graft copolymerization of chitosan with acrylonitrile (AN) was carried out by free radical polymerization using KMnO4 and oxalic acid as a combined redox initiator system. Graft copolymerization was confirmed by Fourier transform infrared spectra (FTIR), proton nuclear magnetic resonance spectra (1H-NMR), thermal gravimetric analysis (TGA) measurements, and wide angle X-ray diffraction (WAXD). In addition, further modification of the cyano groups of the grafted copolymers was performed by partial hydrolysis into carboxylic function groups with various extents. The extent of hydrolysis was monitored using FTIR spectroscopy. The potential of the hydrolyzed and unhydrolyzed grafted copolymers as polymeric carriers for drug delivery systems was extensively studied by preparation of tablets incorporated with methyl orange (MO) as a drug model. In vitro drug release was carried out in simulated gastric and intestinal conditions. The effects of grafting percentage (GP) and the extent of hydrolysis on the release kinetics were evaluated. Release continued up to 24 h for both hydrolyzed and unhydrolysed chitosan-g-PAN copolymers. The nature of drug transport through the polymer matrices was studied by comparing with power law or Kormeyer-Peppas equation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
- Published
- 2010
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39. Adsorption of Cu(II), Co(II), and Ni(II) ions by modified magnetic chitosan chelating resin
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Yen Wei, D.M. Ayad, Mohamed Monier, and A.A. Sarhan
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Thermogravimetric analysis ,Langmuir ,Environmental Engineering ,Health, Toxicology and Mutagenesis ,Metal ions in aqueous solution ,Inorganic chemistry ,Analytical chemistry ,symbols.namesake ,Magnetics ,Adsorption ,Nickel ,Metals, Heavy ,Environmental Chemistry ,Freundlich equation ,Waste Management and Disposal ,Chelating Agents ,Chelating resin ,Chitosan ,Chemistry ,Temperature ,Langmuir adsorption model ,Cobalt ,Pollution ,Kinetics ,Resins, Synthetic ,Chemisorption ,symbols ,Copper - Abstract
Cross-linked magnetic chitosan-isatin Schiff's base resin (CSIS) was prepared for adsorption of metal ions. CSIS obtained was investigated by means of FTIR, 1 H NMR, wide-angle X-ray diffraction (WAXRD), magnetic properties and thermogravimetric analysis (TGA). The adsorption properties of cross-linked magnetic CSIS resin toward Cu 2+ , Co 2+ and Ni 2+ ions were evaluated. Various factors affecting the uptake behavior such as contact time, temperature, pH and initial concentration of the metal ions were investigated. The kinetic parameters were evaluated utilizing the pseudo-first-order and pseudo-second-order. The equilibrium data were analyzed using the Langmuir, Freundlich, and Tempkin isotherm models. The adsorption kinetics followed the mechanism of the pseudo-second-order equation for all systems studied, evidencing chemical sorption as the rate-limiting step of adsorption mechanism and not involving a mass transfer in solution. The best interpretation for the equilibrium data was given by Langmuir isotherm, and the maximum adsorption capacities were 103.16, 53.51, and 40.15 mg/g for Cu 2+ , Co 2+ and Ni 2+ ions, respectively. Cross-linked magnetic CSIS displayed higher adsorption capacity for Cu 2+ in all pH ranges studied. The adsorption capacity of the metal ions decreased with increasing temperature. The metal ion-loaded cross-linked magnetic CSIS were regenerated with an efficiency of greater than 88% using 0.01–0.1 M ethylendiamine tetraacetic acid (EDTA).
- Published
- 2009
40. Enantioselektive Synthese von Homoallylaminen durch nucleophile Addition von chiralen Allylborreagentien an Imine
- Author
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Ashraf A. El-Shehawy, Katsuhiro Watanabe, Koichi Ito, A.A. Sarhan, and Shinichi Itsuno
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Chemistry ,General Medicine - Published
- 1997
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41. Differential Expression of Candidate Virus Receptors in Human T Lymphocytes Prone or Resistant to Infection with Patient-Derived Hepatitis C Virus
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Tomasz I. Michalak, Annie Y. Chen, and Mohammed A.A. Sarhan
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CD36 Antigens ,Gastroenterology and hepatology ,lcsh:Medicine ,Hepacivirus ,Jurkat cells ,Hepatitis ,Jurkat Cells ,Interleukin 21 ,0302 clinical medicine ,T-Lymphocyte Subsets ,Cytotoxic T cell ,IL-2 receptor ,lcsh:Science ,0303 health sciences ,Multidisciplinary ,T Cells ,Natural killer T cell ,Hepatitis C ,3. Good health ,Infectious hepatitis ,medicine.anatomical_structure ,Gene Knockdown Techniques ,Receptors, Virus ,Medicine ,Infectious diseases ,030211 gastroenterology & hepatology ,Research Article ,Immune Cells ,T cell ,Immunology ,Viral diseases ,Biology ,CD5 Antigens ,Microbiology ,Cell Line ,Tetraspanin 28 ,03 medical and health sciences ,Immune system ,Occludin ,Virology ,medicine ,Humans ,Antigen-presenting cell ,Liver diseases ,030304 developmental biology ,Host Cells ,lcsh:R ,Molecular biology ,digestive system diseases ,Gene Expression Regulation ,Claudins ,Leukocytes, Mononuclear ,Clinical Immunology ,lcsh:Q ,Viral Transmission and Infection - Abstract
Accumulated evidence implies that hepatitis C virus (HCV) infects not only the liver but also the immune system. A lymphocyte-specific CD5 molecule was recently identified as essential for infection of T cells with native, patient-derived HCV. To assess whether the proposed hepatocyte receptors may also contribute to HCV lymphotropism, expression of scavenger receptor-class B type 1 (SR-B1), claudin-1 (CLDN-1), claudin-6 (CLDN-6), occludin (OCLN), CD5 and CD81 was examined by real-time RT-PCR and the respective proteins quantified by immunoblotting in HCV-prone and resistant T cell lines, peripheral blood mononuclear cells (PBMC), primary T cells and their subsets, and compared to hepatoma Huh7.5 and HepG2 cells. SR-B1 protein was found in T and hepatoma cell lines but not in PBMC or primary T lymphocytes, CLDN-1 in HCV-resistant PM1 T cell line and hepatoma cells only, while CLDN-6 equally in the cells investigated. OCLN protein occurred in HCV-susceptible Molt4 and Jurkat T cells and its traces in primary T cells, but not in PBMC. CD5 was displayed by HCV-prone T cell lines, primary T cells and PBMC, but not by non-susceptible T and hepatoma cell lines, while CD81 in all cell types except HepG2. Knocking-down OCLN in virus-prone T cell line inhibited HCV infection, while de novo infection downregulated OCLN and CD81, and upregulated CD5 without modifying SR-B1 expression. Overall, while no association between SR-B1, CLDN-1 or CLDN-6 and the susceptibility to HCV was found, CD5 and CD81 expression coincided with virus lymphotropism and that of OCLN with permissiveness of T cell lines but unlikely primary T cells. This study narrowed the range of factors potentially utilized by HCV to infect T lymphocytes amongst those uncovered using laboratory HCV and Huh7.5 cells. Together with the demonstrated role for CD5 in HCV lymphotropism, the findings indicate that virus utilizes different molecules to enter hepatocytes and lymphocytes.
- Published
- 2013
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42. Synthesis of the N-terminal of the Ice Nucleation Protein Gene of Pseudomonas syringae by Assembly PCR
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., Mohammed A.A. Sarhan, additional, ., Mustaffa Musa, additional, ., Norazmi Mohd Nor, additional, and ., Zainul F. Zainuddin, additional
- Published
- 2005
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43. Some social and dietary factors associated with obesity among adults in Egypt
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M.E. El-Prince, E.K. Amine, A.K. Amine, A.A. Sarhan, A.O. Darwish, H.E. Ali, and M.H. Khalil
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business.industry ,Environmental health ,Medicine ,Animal Science and Zoology ,Dietary factors ,business ,medicine.disease ,Agronomy and Crop Science ,Applied Microbiology and Biotechnology ,Obesity ,Food Science - Published
- 1994
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44. [Untitled]
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A.A. Sarhan and Mohamed Mahmoud Abou El-Zahab
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inorganic chemicals ,chemistry.chemical_classification ,organic chemicals ,Resolution (electron density) ,technology, industry, and agriculture ,macromolecular substances ,Polymer ,Mandelic acid ,chemistry.chemical_compound ,Stereospecificity ,Enzyme ,chemistry ,Polymer chemistry ,Organic chemistry - Abstract
Polymere prepare a partir de l'acide 1,2-O(vinyl-4 phenyl) boronate L-mandelique en presence d'une base polymerisable telle que la vinyl-2(4) pyridine
- Published
- 1987
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45. [Untitled]
- Author
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A.A. Sarhan
- Subjects
chemistry.chemical_classification ,Reaction mechanism ,chemistry.chemical_compound ,chemistry ,Yield (chemistry) ,Polymer chemistry ,Polymer ,Optical rotation ,Phenylboronic acid ,Mandelic acid ,Divinylbenzene ,Chiral resolution - Abstract
L-Mandelic acid-1,2-O-(4-vinylphenyl)boronate (2) was copolymerized with divinylbenzene to yield a highly crosslinked macroporous polymer. 59% of incorporated L-mandelic acid (used as template) could be split-off on hydrolysis. The resulting polymer, with phenylboronic acid groups in the chiral cavities of type P1, was equilibrated in a batch process with D,L-mandelic acid in acetonitrile. The change of covering percentage, and that of the efficiency for racemic resolution, with time were followed by acidimetric titration and measurement of the optical rotation. A reasonable mechanism for the polymer-substrate interaction could de deduced. The selectivity terms for each of the forward and reverse reaction could be separately evaluated. Diffusional limitations significantly affect the observed efficiency of racemic resolution. Thermodynamically controlled separation, attainable by a suggested exchange reaction, required much more time than the considerably less effective kinetically controlled separation.
- Published
- 1989
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46. Über enzymanalog gebaute Polymere, III. Zur Synthese von polymerisierbaren <scp>D</scp> ‐Glycerinsäurederivaten
- Author
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Günter Wulff, Ernst Lohmar, Jürgen Gimpel, and A.A. Sarhan
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Inorganic Chemistry ,chemistry.chemical_compound ,Ethylene ,chemistry ,Benzyl alcohol ,Polymer chemistry ,Alcohol ,Methanol ,Spatial relationship - Abstract
Als Ausgangssubstanzen zur Einfuhrung von funktionellen Gruppen in Polymere in vorgegebener Nachbarschaftsbeziehung wurden eine Reihe von polymerisierbaren D-Glycerinsaurederivaten synthetisiert, u. a. D-Glycerinsaure-(p-vinylanilid)-2,3-O-(p-vinylphenylboronat) (1a) sowie von 1a abgeleitete Homologe mit einer Athylengruppe zwischen der Amido- bzw. der Boronatgruppe und dem Benzolring (6, 7 und 8). Auserdem wurden die p-Vinyl-phenylboronate der D-Glycerinsaureester des Methanols (11a), des n-Octanols (11b), des Benzylalkohols (11c) und des p-Nitrobenzylalkohols (11d) dargestellt. Polymers of Enzyme-Analogous Structure, III On the Synthesis of Polymerizable Derivatives of D-Glyceric Acid As starting materials for the introduction of functional groups into polymers in a given spatial relationship a number of polymerizable derivatives of D-glyceric acid were prepared, including D-glyceric (p-vinylanilide) 2,3-O-(p—vinylphenylboronate) (1a). In addition compounds derived from 1a have been prepared in which the amido and the boronate groups are separated from the benzene ring by a spacer of a ethylene group (6,7, and 8). Furthermore the p-vinylphenylboronates of D-glyceric acid esters of methanol (11a), n-octanol (11b), benzyl alcohol (11c), and p-nitrobenzyl alcohol (11d) have been prepared.
- Published
- 1974
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47. [Untitled]
- Author
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Wolfgang Vesper, Günter Wulff, A.A. Sarhan, and R. Grobe‐Einsler
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chemistry.chemical_classification ,chemistry.chemical_compound ,Enzyme ,Materials science ,chemistry ,Resolution (electron density) ,Polymer chemistry ,Copolymer ,Polymer ,Methyl methacrylate ,Cleavage (embryo) ,Ethylene dimethacrylate ,Boronic acid - Abstract
By copolymerization of 4-nitrophenyl α-D-mannopyranoside-2,3;4,6-di-O-(4-vinylphenylboronate) (1) with ethylene dimethacrylate and methyl methacrylate macroporous polymers were obtained, in which after cleavage of the template, 4-nitrophenyl α-D-mannopyranoside (2), chiral cavities with two boronic acid groups are present. From the dependence of the specificity for the resolution of racemates on the covering percentage of the cavities the frequency distribution of the specificity of the cavities could be deduced. With the distribution curve at hand the factors are discussed, which govern the conservation and the loss of specificity.
- Published
- 1977
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48. The photodegradation of cis-1,4-polybutadiene, polystyrenebutadiene and polyisoprene
- Author
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E.A. Abdel-Razik, A.A. Sarhan, and E. M. Abdel-Bary
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chemistry.chemical_classification ,Singlet oxygen ,General Chemical Engineering ,General Physics and Astronomy ,General Chemistry ,Polymer ,Photochemistry ,chemistry.chemical_compound ,Differential scanning calorimetry ,Polybutadiene ,chemistry ,Natural rubber ,visual_art ,Polymer chemistry ,visual_art.visual_art_medium ,Solvent effects ,Photodegradation ,Methylene blue - Abstract
The photodegradation of the synthetic rubbers cis -1,4-polybutadiene, polystyrenebutadiene and polyisoprene was studied. The chemical structure of the polymers as well as the effect of changing the solvent and the additive were particularly taken into consideration. The polychloroprene rubber in this study was irradiated either as a film or in solution. The presence of methylene blue affects the endothermic peaks observed in its differential scanning calorimetry diagrams. Methylene blue acts as a photostabilizer dye in solutions and films of polychloroprene. Mixtures of methylene blue, β-carotene as a singlet oxygen quencher and Fmbanox as a known anti-oxidant showed synergystic behaviour.
- Published
- 1987
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49. Über enzymanalog gebaute polymere, 14. Stereospezifische haftungen über amidbindung oder elektrostatische wechselwirkung
- Author
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A.A. Sarhan and Günter Wulff
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Glyceric acid ,chemistry.chemical_classification ,chemistry.chemical_compound ,Monomer ,Chemistry ,Covalent bond ,Polymer chemistry ,Peptide bond ,Polymer ,Borane ,Acetonitrile ,Divinylbenzene - Abstract
D-N-(4-vinylphenyl)carbamoylethylenedioxy(4-vinylphenyl)borane (1) with D-glyceric acid as template was copolymerized with technical divinylbenzene by a radical mechanism in the presence of various amounts of acetonitrile as an inert solvent. The resulting differences in the structure and swellability of the polymers are discussed in relation to the specificity of the polymers for the racemic resolution of D,L-glyceric acid. Some of these polymers were found to be able to bind glyceric acid with high optical enrichment by a covalent amide bond. To prevent the formation of the covalent amide bond during the intake reaction, the amide bond in the monomer is replaced by an ion pair relation. For this intention, the synthesis of an appropriate monomer 4-vinyltrimethylanilinium 2-(4-vinylphenyl)-1,3,2-dioxaborolan-4-carboxylate (2) and the investigation of the resulting polymers are described.
- Published
- 1982
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50. Effect of graft copolymerization of 2-hydroxyethyl methacrylate on the properties of polyester fibers and fabric
- Author
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A.A. Sarhan, E. M. Abdel-Bary, and H. H. Abdel-Razik
- Subjects
Polyester ,Synthetic fiber ,Materials science ,Polymers and Plastics ,Polymer chemistry ,Materials Chemistry ,Copolymer ,General Chemistry ,Grafting ,Surfaces, Coatings and Films ,2-Hydroxyethyl Methacrylate - Published
- 1988
- Full Text
- View/download PDF
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