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Search Results: 1 - 10 of 464388 matches for " Sundus A. Abdullah "
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The Mechanism of Interacting Stellar Winds beyond Red Giant Branch  [PDF]
Sundus A. Abdullah Albakri, Sinan H. Ali
International Journal of Astronomy and Astrophysics (IJAA) , 2013, DOI: 10.4236/ijaa.2013.34041
Abstract:

The dynamical processes of the interaction of slow wind beyond Red Giant phase with fast wind of central star of nebula are evaluated. The mechanism of interaction stellar wind model (ISW) is found to be responsible for producing a relatively dense shell of gas which increases in mass and radius at a constant rate. Both slow wind and superwind are assumed to be time independent and radial density is calculated at initial time to ~ 60 yrs with the fast wind velocity (v 1000 km/s). The results showed that, at the outer rim of super wind region, a small density hump appears due to the relative velocity between slow winds and central star winds, in a good agreement with the previous models. The dynamical requirements of the observed expansion of planetary nebulae can be satisfied by the mechanism of interacting stellar wind model with reasonable mass loss rate from central star.

Distances Scale Determination for a Planetary Nebula in Galactic Bulge  [PDF]
Sundus A. Abdullah, Nathera A. Ali, Mohamed A. Sallih
International Journal of Astronomy and Astrophysics (IJAA) , 2013, DOI: 10.4236/ijaa.2013.32008
Abstract:

Planetary Nebulae (PN) distances represent the fundamental parameter for the determination the physical properties of the central star of PN. In this paper the distances scale to Planetary Nebulae in the Galactic bulge were calculated related to previous distances scales. The proposed distance scale was done by recalibrated the previous distance scale technique CKS/D82. This scale limited for nearby PN (D ≤ 3.5 kpc), so the surface fluxes less than other distance scales. With these criteria the results showed that the proposed distance scale is more accurate than other scales related to the observations for adopted sample of PN distances, also the limit of ionized radius (Rio) for all both optically thick and optically thin in the rang of sizes (0.45 > Rio (pc) > 0.03).

Cytokeratin positivity in myxopapillary ependymoma – a potential diagnostic pitfall
Sundus A Hussein, Monalisa Sur
Diagnostic Pathology , 2008, DOI: 10.1186/1746-1596-3-40
Abstract: We describe two cases of MPE with cytokeratin (AE1 AE3, CAM 5.2, Cytokeratin 7 and cytokeratin 20) expression.MPE can be positive for Cytokeratins (CAM 5.2, AE1 AE3, CK7) and focally for EMA, which could be misdiagnosed as metastatic carcinoma. In cases demonstrating epithelioid and clear cell morphology, the diagnosis of MPE should be made in conjunction with histology, proper immunohistochemical profile which includes co-expression of GFAP, S-100 protein and epithelial markers, radiologic findings and site. It is important to be aware of the cytokeratin profile in MPE to avoid erroneous diagnosis with other tumour entities.Myxopapillary ependymomas (MPE) generally occur in the filum terminale of the spinal cord, however, they have been described in extra-spinal locations such as subcutaneous tissue [1] and brain [2]. They are slow growing gliomas corresponding to WHO grade I [3]. The classical morphology shows papillae embedded in a myxoid/mucoid background. Each papilla contains a central fibrovascular core and is lined by cuboidal to elongated cells, occasionally showing clear cytoplasm. Microcysts are also present. The myxoid background contains both neutral and acidic mucopolysaccharides. Prognosis depends on the completeness of excision [4]. However, areas of solid growth pattern with aggregates of cells with "epithelioid morphology" can also be encountered which can mimic metastatic carcinoma. In addition, the presence of cells with clear cytoplasm can also be mistaken for chordoma. Diagnosis is easily missed due to these morphological similarities, which could affect patient management and hence, long term survival. A good number of studies have reported the immunophenotype of MPE and differential diagnosis of MPE aided by immunohistochemical stains [5-7]. Several studies have reported absence of cytokeratin expression in MPE [8-10].We describe two cases of MPE with cytokeratin expression. Two female patients, aged 46 and 72 years respectively presented wit
The Effects of a Health-Based Context on Memory for Advertisements  [PDF]
Sundus Mahdi, Adrian Furnham
Psychology (PSYCH) , 2016, DOI: 10.4236/psych.2016.78117
Abstract: This study looked at whether heath-based advertisements were remembered when placed in a health (congruity) or non-health (incongruity) based television programme and the extent to which participant involvement influenced recall. The study aimed to test whether programme context had an effect on memory for congruent or incongruent advertisements. Sixth-form students watched either a health or non-health programme, with health or non-health centre-break advertisements. Sessions took place during the morning and afternoon. Free recall and cued recall tests were administered to test memory for the TV adverts. Results found no support for the cognitive priming theory, cognitive interference theory or for contrast effects. The study found little evidence to support any theory as to why programme surround should influence the recall of health advertisements. Limitations of the study are considered.
The Effect of Zn Concentration on the Optical Properties of Cd10–xZnxS Films for Solar Cells Applications  [PDF]
Nathera A. Al-Tememee, Nada M. Saeed, Sundus M. A. Al-Dujayli, Baha T. Chiad
Advances in Materials Physics and Chemistry (AMPC) , 2012, DOI: 10.4236/ampc.2012.22012
Abstract: In this paper, Cd10–xZnxS (x = 0.1, 0.3, 0.5) films were deposited by using chemical spray pyrolysis technique, the molar concentration precursor solution was 0.15 M/L. Depositions were done at 350?C on cleaned glass substrates. X-ray diffraction technique (XRD) studies for all the prepared film; all the films are crystalline with hexagonal structure .The optical properties of the prepared films were studied using measurements from VIS-UV-IR spectrophotometer at wave-length with the range 300 - 900 nm; the average transmission of the minimum doping ratio (Zn at 0.1%) was about 55% in the VIS region, it was decrease at the increasing of Zn concentration in the CdS films, The band gap of the doped CdS films was varied as 3.7, 3.8, 3.6 eV at x = 0.1, 0.3 and 0.5 respectively.
Comparative Assessment of Melatonin-Afforded Protection in Liver, Kidney and Heart of Male Mice against Doxorubicin Induced Toxicity  [PDF]
Abdullah A. Alghasham
Pharmacology & Pharmacy (PP) , 2013, DOI: 10.4236/pp.2013.48085
Abstract: Melatonin (MEL) was investigated for protection against the anthracycline antibiotic doxorubicin (Dox) that is well known for its oxidative damage to various body organs. It was aimed to have a comparison of this protection to heart, liver and kidney in the treated subjects. In this study, groups of mice were treated with Dox and melatonin and their individual or combined effects were evaluated by assessing lipidperoxidation, non-protein sulfhydryls (NP-SH) and nitrate/nitrite (NO) contents in these tissues. Plasma aminotransferases, LDH and CK-MB enzyme activities were measured. Moreover, these tissues were subject to histopathological assessment. MEL co-treatment significantly prevented any rise in lipidperoxides more significantly in heart and liver as compared to kidney. In tandem, MEL prevented a decline in GSH that was observed by Dox alone in liver and kidney. Dox significantly increased total NO levels in all the tissues. Melatonin at both dose levels could not afford protection against nitrosative stress. MEL in combination treatment provided significant (P < 0.01) decline in CK-MB at both the doses and only 5 mg/kg dose significantly prevented a rise in LDH activity and prevented any histopathological change. Melatonin, probably by behaving as an antioxidant prevented Dox-induced lipidperoxidation in heart, liver and kidney tissues and a decline in NP-SH. However, administration of MEL is able to decrease parameters of oxidative, and nitrosative stress in heart and liver more effectively than kidney.
Photocatalytic Degradation of Rhodamine B Dye in Wastewater Using Gelatin/CuS/PVA Nanocomposites under Solar Light Irradiation  [PDF]
Abdullah A. Al-Kahtani
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2017, DOI: 10.4236/jbnb.2017.81005
Abstract: The crosslinked gelatin/CuS/PVA nanocomposite catalyst prepared using gamma irradiation as initiator was extensively characterized using several techniques including transmission electron microscopy (TEM), UV-Vis spectroscopy, infrared spectroscopy (IR) and X-ray diffraction (XRD). We chose Rhodamine B (RhB) dye as a model contaminant in order to investigate its Photocatalytic activity under solar light irradiation. The effects of pH, catalyst concentration and RhB concentration on degradation reaction were also investigated. Similar to the observed trend for the photocatalytic oxidation of other organic compounds, the efficiency of photocatalytic degradation of RhB tended to decrease with increasing the concentration of RhB. The degradation efficiency of RhB is found to increase as pH is increased up to pH of 10, then starts decreasing at pH values higher than 10. The degradation efficient of RhB is found to increase as the amount of the catalyst dosage increases up to an optimum value of 0.25 g. Increasing the concentrations of photocatalyst beyond 0.25 g was found to decrease the photocatalytic activity of RhB. It was proven that the degradation process of RhB reaction rate obeyed a pseudo-first-order reaction of the catalyst concentration of gelatin/CuS/PVA nanocomposite. The degradation kinetics was found to fit well Langmuir-Hinshelwood rate law. The results obtained showed that after using the catalyst five times repeatedly, the catalyst retained its efficiency and the rate of the degradation process was still above 80%.
Performance Evaluation of FM-COOK Chaotic Communication System  [PDF]
Hikmat N. Abdullah, Alejandro A. Valenzuela
Journal of Signal and Information Processing (JSIP) , 2011, DOI: 10.4236/jsip.2011.23023
Abstract: In this paper, the performance evaluation of Frequency Modulated Chaotic On-Off Keying (FM-COOK) in AWGN, Rayleigh and Rician fading channels is given. The simulation results show that an improvement in BER can be gained by incorporating the FM modulation with COOK for SNR values less than 10dB in AWGN case and less than 6dB for Rayleigh and Rician fading channels.
Maternal Anthropometric Study of Low Birth Weight Newborns in Saudi Arabia: A Hospital-Based Case-Control Study  [PDF]
Abdullah G. Alkushi, Naser A. El Sawy
Advances in Reproductive Sciences (ARSci) , 2016, DOI: 10.4236/arsci.2016.44012
Abstract: Background: The aim of the study is to investigate the role of socio-demographic, life-style and clinical risk factors of low birth weight (LBW) among pregnant women in Saudi Arabia. It is a hospital-based, case-control study of mothers of 135 LBW and 65 normal birth weight neonates at the Obstetrics and Gynecology Unit of the Maternity and Children Hospital, KSA. Methods: On comparison by Duncan’s test, the gestational age of three LBW groups was found to be significantly different (P = 0.0026). The mean duration of hospital stay of the infants also increased for the LBW, very LBW and extreme LBW groups, and their difference was statistically significant (P = 0.0012). Results: A statistically significant, progressive decline was observed in the weight, length and circumference of the head of infants in the LBW to VLBW to ELBW groups. Conclusion: The present study has assessed the state of this significant public health problem of LBW in KSA, and identified several maternal modifiable risk factors. There is an urgent need for the development of reference charts using current data for the Middle Eastern population.
Petrographic Characterization of the Different Types of Basalts of Harrat Al Fatih, Ablah Area, West Central Arabian Shield, Saudi Arabia  [PDF]
Abdullah R. Sonbul, Ali A. Mesaed
Open Journal of Geology (OJG) , 2017, DOI: 10.4236/ojg.2017.76060
Abstract: Harrat Al Fatih is located southwest of Ablah area, Assir terrain, southwestern Arabian Shield. It is present as black laterally extended horizontal basaltic sheet just overlying folded strata of the volcano-sedimentary succession of Ablah Formation (green mudstones, dolostones and green and red volcaniclastic red beds). These basalts are rift-related and represent part of the Oligo-Miocene basic volcanics of the western part of Saudi Arabia. The detailed field and microscopic description of these basalts enable the author to classify it into two main types: 1) Grey tuffaceous glassy basalts that present overlying the Ablah Formation. This basalt type is generally soft, bedded and intercalated with grey, green and red tuffaceous mudstones. Microscopically it composed of minute lath-like plagioclase and pyroxene crystals embedded in glassy groundmass. 2) Black olivine-rich basalts which are present in the topmost part of harrat Al Fatih are generally black, hard and contain remarkable reddish brown oxidized olivine spots and some calcite and amorphous quartz domains. Under the microscope, this basalt type is microcrystalline and composed mainly of lamellar twined Ca-plagioclase and colored olivines and pyroxenes. The olivines show different stages of oxidation and formation of amorphous blood red iron-oxyhydroxides and black hematite. The present study revealed the formation of the grey basalts at the initial stages of the volcanic eruption in ephemeral lakes and the second type of basalt was during the consolidation of proper basic magmas at the final stages of the volcanic eruption.
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