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Search Results: 1 - 10 of 468697 matches for " Mohamed A. Siddig "
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Effect of the Cation Size Disorder at the A-Site on the Structural Properties of SrAFeTiO6 Double Perovskites (A = La, Pr or Nd)  [PDF]
Abdelrahman A. Elbadawi, O. A. Yassin, Mohamed A. Siddig
Journal of Materials Science and Chemical Engineering (MSCE) , 2015, DOI: 10.4236/msce.2015.35003
Abstract: In this paper, the cation size disorder effect of the A-site on the structural properties of the SrAFe- TiO6 (A = La, Pr or Nd) was investigated. The compounds were synthesized—as the best of our knowledge—for the first time by conventional and precursor method to get crystalline materials. The results obtained from the experimental measurements carried out on new double perovskite materials were presented. The data of X-ray diffraction (XRD), Fourier Transform Infra Red FTIR were measured at room temperature. From the X-ray diffraction, and by means of standard Rietiveld method, all the samples have the same structure (orthorhombic) with Pnma space group. The difference in the tolerance factor is clearly noticed and refers to the cation size disorder at the A-sites. The Fourier Transform Infra Red FTIR measurement has been done; the results of it confirm the double perovskite structure and the difference between the samples were noticed. The tolerance factors for the samples altered from SrLaFeTiO6 up to SrNdFeTiO6 and this difference return to ionic radius and cation size effect.
Structural and Optical Properties of Mg1-x Znx Fe2 O4 Nano-Ferrites Synthesized Using Co-Precipitation Method  [PDF]
Abdalrawf I. Ahmed, Mohamed A. Siddig, Abdulmajid A. Mirghni, Mohamed I. Omer, Abdelrahman A. Elbadawi
Advances in Nanoparticles (ANP) , 2015, DOI: 10.4236/anp.2015.42006
Abstract: In this work, the Mg1-x Znx Fe2 O4 Nanoferrites (where x = 0.0, 0.2, 0.4, 0.6 and 0.8) was synthesized using co-precipitation method. The investigation of structural and optical properties was carried out for the synthesized samples using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Ultraviolet visible spectrophotometer (UV-Vis). XRD revealed that the structure of these nanoparticles is spinel with space group Fd3m and crystallite size lies in the range 21.0 - 42.8 nm. Lattice parameter was found to increases with Zn concentration and this may be due to the larger ionic radius of the Zn2+?ion. FTIR spectroscopy confirmed the formation of spinel ferrite and showed the characteristics absorption bands around 612, 1146, 1404, 1649 and 3245 cm-1. The energy band gap was calculated for samples with different ratio and was found to be 4.77, 4.82, 4.86, 4.87 and 4.95 eV. The substitution was resulted in slight increased in the lattice constant and that sequentially may lead to the slightly decreased in the energy gap.
The Effect of Replacement of Zn 2+ Cation with Ni 2+ Cation on the Structural Properties of Ba sub>2Zn sub>1–x Ni sub>xWO sub>6 Double Perovskite Oxides (X = 0, 0.25, 0.50, 0.75, 1)  [PDF]
Yousif A. Alsabah, Abdelrahman A. Elbadawi, Eltayeb M. Mustafa, Mohamed A. Siddig
Journal of Materials Science and Chemical Engineering (MSCE) , 2016, DOI: 10.4236/msce.2016.42007
Abstract: The Ba2Zn1-xNixWO6 double perovskite oxides were synthesized using solid state reaction method. The effect of replacement of Zn2+ with Ni2+ cation on the structural properties was investigated by X-ray diffraction (XRD) at room temperature. From the X-ray diffraction and by means of standard Rietiveld method, the samples showed the same cubic crystal structure with (Fm-3m) space group and the crystallite size ranging from 71.91 nm to 148.71 nm. The unit cell volume was found to decrease as a result of the replacement, while there was no significant difference in the value of tolerance factor of the samples. This is may be due to the convergence of ionic radii of Ni2+ and Zn2+ cations. The Fourier Transform Infrared Spectroscopy (FTIR) was performed for the samples and the resultant characteristic absorption bands confirmed the double perovskite structure.
Effect of Cu2+ Doping on Structural and Optical Properties of Synthetic Zn0.5CuxMg0.5-xFe2O4 (x = 0.0, 0.1, 0.2, 0.3, 0.4) Nano-Ferrites  [PDF]
Badawi M. Ali, Mohamed A. Siddig, Yousef A. Alsabah, Abdelrahman A. Elbadawi, Abdalrawf I. Ahmed
Advances in Nanoparticles (ANP) , 2018, DOI: 10.4236/anp.2018.71001
Abstract: The samples of Zn0.5CuxMg0.5-xFe2O4 nanoparticle ferrites, with x= 0.0, 0.1, 0.2, 0.3, 0.4 were successfully synthesised. Structural and optical properties were investigated by X-ray Diffraction (XRD), Fourier Transform Infrared spectros-copy (FTIR) and UV-visible spectroscopy. The structural studies showed that all the samples prepared through the Co-precipitation method was a single phase of a face-cantered-Cubic (FCC) spinel symmetry structures with space group (SG): Fd-3m. In the series Zn0.5CuxMg0.5-xFe2O4, the lattice parameter was found to be 8.382 ? for x = 0 and was found to increase with copper con-centration. The grain size obtained from the XRD data analyses was found to be in the range of 15.97 to 28.33 nm. The increased in the grain size may be due to the large ionic radius of Mg2+ (0.86 ?) compared with Cu2+ (0.73 ?). The FTIR spectroscopy confirmed the formation of spinel ferrite and showed the characteristics absorption bands around 580, 1112, 1382, 1682, 1632 and 2920 cm-1. The energy band gap was calculated for samples were found to be in the range 4.04 to 4.67 eV.
Why Did Sudanese End Stage Renal Failure Patients Refuse Renal Transplantation?  [PDF]
Amin S. Banaga, Elaf B. Mohammed, Rania M. Siddig, Diana E. Salama, Sara B. Elbashir, Mohamed O. Khojali, Rasha A. Babiker, Khalifa Elmusharaf, Mamoun M. Homeida
Open Journal of Nephrology (OJNeph) , 2015, DOI: 10.4236/ojneph.2015.52005
Renal transplantation remains the most effective treatment of End Stage Renal Failure (ESRF). In this cross sectional study we explore the reasons behind refusal of renal transplantation among adults’ Sudanese haemodialysis patients. The subjects of the study are ESRF adults’ patients on regular haemodialysis treatment in 15 haemdoialysis centres in Khartoum/Sudan. All patients who are on regular haemodialysis were interviewed by questionnaire to explore the reasons of refusal of renal transplantation. A total of 1583 ESRF adults’ patients on regular haemodialysis have been participated in the study, 381 (24.1%) patients refused kidney transplantation. The mean age of patients refusing kidney transplantation was (58.5 + 15.1 years); 77.4% of them were ≥50 years old, 59.2% were males and 88.1% were unemployed, patients older than 50 years old and unemployed are tend to refuse renal transplantation (P < 0.001). The main reason of refusal was that the patients refuse to accept kidney from living donors (34.8%). 17.6% of patients decline kidney transplantation because of financial reason, 18.1% of patients refused to do transplantation because of fear of transplant surgery, 15.7% of patients believe that kidney transplantation is against their religious values, 11.9% of patients refused transplantation because they don’t have enough knowledge on renal transplantation, only 0.5% of patients refuse transplantation because of side effect of immunosuppressive drugs. In conclusion, in this study we found that elderly and unemployed ESRF patients tend to refuse renal transplantation, the most important reason behind refusal of renal transplantation is refusal of accepting kidney donation from living related donors. This reflects the need for development of cadaveric donors program in the Sudan. ESRF patients need education and counseling on renal transplantation.
Degradation of Oxyfluorfen Herbicide by Soil Microorganisms Biodegradation of Herbicides
Afrah T. Mohamed,Adil A. El Hussein,Marmar A. El Siddig,Awad G. Osman
Biotechnology , 2011,
Abstract: Three laboratory experiments were carried out to study the biodegradation of Oxyfluorfen herbicide (Goal) in a soil with no history of pesticides application at two temperatures (28 and 40C) with or without the addition of mineral fertilizers (NPK). Different concentrations of Oxyfluorfen were applied to the soil samples and the herbicide residue was determined using Gas Liquid Chromatography (GLC) at 0 time and then at 15 days intervals for 45 days. Various genera of microorganisms were isolated on different semi-selective media from soils treated with different concentrations of Oxyfluorfen. The ability of these isolates to utilize Oxyfluorfen as a sole source of carbon and energy was studied. Results indicated that biodegradation of Oxyfluorfen in soil incubated at 40C after 45 days of incubation was better (55.2-78.3%) than in soil incubated at 28C (17.5-36.6%). Addition of mineral fertilizers (NPK) increased the biodegradation of Oxyfluorfen in soils. Intensive degradation (27.8-55.5%) was observed in NPK fertilized soils incubated at 40C after 15 days of incubation at all Oxyfluorfen concentrations. Ten potential Oxyfluorfen degraders were identified. Results obtained showed that within 21 days, Bacillus spp. had the ability to degrade 80-95.6% of Oxyfluorfen followed by Pseudomonas sp. (82.2%), Arthrobacter spp. (82.2%), Aspergillus sp. (77.8%), Mycobacterium sp. (75.6%), Micrococcus sp. (73.3%) and Streptomyces sp. (68.9%). It could be concluded that biodegradation of Oxyfluorfen in soils is significantly affected by temperature and the microbial species. These microorganisms are considered as potential candidates for use in any program aiming at decontamination of Oxyfluorfen polluted sites.
Frequency Dependence of Atomic Diffusivity and Electrical Properties of Gum Arabic/Graphite Composite  [PDF]
Bilquis Ibrahim Adham, Hatim Mohamed El-Khair, Mohamed Ahmed Siddig
Journal of Materials Science and Chemical Engineering (MSCE) , 2015, DOI: 10.4236/msce.2015.39004
Abstract: In this study, Gum Arabic (GA)/Graphite (Gr) composite material was prepared using solid state reaction method. The FTIR peaks obtained were referred to the binding of Gr with the active groups in GA, such as NH2, COOH, CHO, CNC (alkyl amine) and C=CH (aromatic monosubstitution). Atomic diffusivity of Gr in GA was calculated using simple model and was found to varied randomly. This randomness might be due to the attachment of Gr with different active groups of GA. The addition of Gr results in improvement of the conductivity of GA to a far extend as it reaches the semiconductor range. The random variation in conductivities of the samples can be attributed to the effect of high frequency range, where the effect of phonon-electron is dominant. The samples subjected to the impedance spectroscopy (IS) for second and third time were acquired different diffusivities as well as conductivities. Such variations might indicate that IS was a processing technique similar to thermal treatment since it boosted the Gr atomic diffusion.
Toxicological Features of Catha edulis (Khat) on Livers and Kidneys of Male and Female Sprague-Dawley Rats: A Subchronic Study
Abdulsamad Alsalahi,Mahmood Ameen Abdulla,Mohammed Al-Mamary,Mohamed Ibrahim Noordin,Siddig Ibrahim Abdelwahab,Aied M. Alabsi,Abdrabuh Shwter,Mohammed A. Alshawsh
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/829401
Abstract: Hepato- and nephrotoxicity of Khat consumption (Catha edulis Forskal) have been evoked. Therefore, this study was conducted to evaluate such possible hepatorenal toxicity in female and male Sprague-Dawley rats (SD rats) focusing primarily on liver and kidney. In addition, female and male rats were investigated separately. Accordingly, forty-eight SD-rats (100–120 g) were distributed randomly into four groups of males and female (). Normal controls (NCs) received distilled water, whereas test groups received 500 mg/kg (low dose (LD)), 1000 mg/kg (medium dose (MD)), or 2000 mg/kg (high dose (HD)) of crude extract of Catha edulis orally for 4 weeks. Then, physical, biochemical, hematological, and histological parameters were analyzed. Results in Khat-fed rats showed hepatic enlargement, abnormal findings in serum aspartate aminotransferase (AST), and alkaline phosphatase (ALP) of male and female SD-rats and serum albumin (A) and serum creatinine (Cr) of female as compared to controls. In addition, histopathological abnormalities confirmed hepatic and renal toxicities of Khat that were related to heavy Khat consumption. In summary, Khat could be associated with hepatic hypertrophy and hepatotoxicity in male and female SD-rats and nephrotoxicity only in female SD-rats.
Genome-Wide SNPs Identification and Determination of Proteins Associated with Stress Response in Sorghum (Sorghum bicolor L. Monech) Accessions  [PDF]
Hind Emad Fadoul, Marmar A. El Siddig, Abdel Wahab H. Abdalla, Adil A. El Hussein
American Journal of Plant Sciences (AJPS) , 2017, DOI: 10.4236/ajps.2017.87112
Abstract: Current efforts in sorghum breeding programs are exploiting genotyping-by-sequencing (GBS) data to provide full-genome scans for desired traits. The aim of this study was to utilize GBS approach for the identification of genomic regions associated with stress response in sorghum (Sorghum bicolor L. Monech) accessions. DNA samples of twenty sorghum accessions, having different response to drought, were used to prepare GBS libraries for sequencing. SNPs were called using the TASSELGBS pipeline and the tags that present at least 10 times in the dataset were considered and aligned to the reference genome of Sorghum bicolor. The identified SNPs were all compared with the published sorghum transcript related to stress response gene activity. Overall; 94.40% tags were aligned and 69,736 putative SNPs positions were identified. Blast search revealed homology to annotated heat and drought–tolerance associated genes which code for ATPases, Peroxidase, Hydrophobic protein LTI6A, Aquaporin SIP2-1, Aconitate hydratase and phosphatidylinositol-4-phosphate-5-kinase. The phylogeny of the 20 accessions was constructed using the generated SNPs data. Phylogenetic analysis data showed that the phenotypically tolerant line (El9)?makes a separate cluster and the same for the accessions HSD8653 and HSD5612 near to the cluster that includes most accessions with known post-flowering drought tolerance (HSD7410, HDS10033, HSD8552, GESHEISH and HSD8849). Post-flowering drought sensitive accessions (Tabat, Wadahmed, HSD6468 and HSD6478) formed a separate cluster while the sensitive accession HSD9959 and the tolerant accessions HSD8511 and HSD9566 were distributed between the two clusters. Thus, cluster analysis confirmed the variation among accessions in post-flowering drought tolerance. With further validation, these markers may be used for marker assisted selection for breeding new sorghum genotypes with stress adaptation.
Glacier Mass-Balance Variation in China during the Past Half Century  [PDF]
Yousif Elnour Yagoub, Zhongqin Li, Ahmed A. H. Siddig, Omer Said Musa, Muhammad Naveed Anjum
Journal of Geoscience and Environment Protection (GEP) , 2018, DOI: 10.4236/gep.2018.65004
The aim of this study is to investigate the impact of temperature trend on glacier-mass balance, snow density, snowmelt, snow depth and runoff by using observations of nine glacier stations that covered most of the China over the period of 1979-2013. Trend analysis showed an increasing trend of temperature on all of the selected stations. On an average, temperature was increasing at the rate of 0.46/10a. The increasing trend of temperature showed a negative relationship with annual glacier-mass balance on most of the stations and caused a decrease in annual balance. Results of Pearson’s correlation analysis showed a highly significant negative correlation between temperature and snow density (correlation coefficient (CC = -0.661 at 0.01 significance level). There was a significant positive correlation between temperature and snowmelt (CC = 0.532 at 0.01 significance level). There was a significant negative correlation between temperature and snow depth (correlation coefficient (CC = -0.342 at 0.05 significance level). Moreover, there was a significant positive correlation between temperature and runoff (CC = 0.586 at 0.01 significance level). Increasing trend of temperature caused an increasing trend of annual snowmelt and runoff anomaly% at the rate of 24.82/10a and 9.87/10a, respectively. On the other hand, a declining trend in annual snow density and snow depth anomaly% was found at a rate of -5.32/10a and -1.93/10a, respectively. We concluded that the snow density, snowmelt and runoff are significantly sensitive to temperature in China. This contribution has provided information for further understanding of glacier variation and its influencing factors.
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