Gansen P.,Otto Bock Kunststoff Holding GmbH |
Dittgen M.,Arab International University
Drug Development and Industrial Pharmacy | Year: 2012
The new technology to manufacture transdermal active patches without solvents or increased temperatures described here is based on polyol and isocyanate reacting to polyurethane (PU) in the presence of the drug. The technology was proven using testosterone (T) as the drug and N,N-Diethyl-m-toluamide (DEET) and Limonene (L) as enhancers for skin permeation. The experimental patches varied in drug content and enhancer concentration. The patches were evaluated regarding adhesion to stainless steel or leather, in vitro drug release and T permeation across human cadaver skin using Franz cell. Comparing the results with those of a parallel investigation of the commercial product, Testopatch®, adhesion to leather and in vitro drug release of the experimental patches were found to be higher. The steady-state flux (J SS) of T from the experimental patches was found lower than Testopatch®. The flux of the experimental patch P3, which had the highest concentration of DEET and a low concentration of L was comparable to J SS of the commercial product, Testopatch®. © 2012 Informa Healthcare USA, Inc.
Baqar M.,Case Western Reserve University |
Baqar M.,Arab International University |
Agag T.,Case Western Reserve University |
Ishida H.,Case Western Reserve University |
Qutubuddin S.,Case Western Reserve University
Polymer | Year: 2011
Historically, applications for traditional phenolic resin/polyurethane materials are limited due to the inherently weak thermal stability of urethane-phenolic linkage and slow reaction rate. A novel concept has been developed to produce phenolic resin/polyurethane copolymers via benzoxazine chemistry. Through one-pot synthesis, a series of linear poly(benzoxazine-co- urethane) materials has been synthesized via the reaction of a newly developed dimethylol functional benzoxazine monomer with 4,4′-methylene diphenyl diisocyanate and poly(1,4-butyleneadipate). The structure of the copolymers has been characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). The copolymers in the film forms have been further thermally treated for crosslinking to produce crosslinked poly(benzoxazine-co-urethane) via the ring opening polymerization of cyclic benzoxazine moieties in the main-chain. The tensile properties of the films have been studied and compared with those of traditional high performance materials. The thermal properties of the crosslinked copolymers have also been studied by dynamic mechanical analysis, and thermogravimetric analysis (TGA). © 2010 Elsevier Ltd. All rights reserved.
al-Swaidani A.,Arab International University |
Hammoud I.,Damascus University |
Meziab A.,Damascus University
Journal of Rock Mechanics and Geotechnical Engineering | Year: 2016
Clayey soils in Syria cover a total area of more than 20,000 km2 of the country, most of which are located in the southwestern region. In many places of the country, the clayey soils caused severe damage to infrastructures. Extensive studies have been carried out on the stabilization of clayey soils using lime. Syria is rich in both lime and natural pozzolana. However, few works have been conducted to investigate the influence of adding natural pozzolana on the geotechnical properties of lime-treated clayey soils. The aim of this paper is to understand the effect of adding natural pozzolana on some geotechnical properties of lime-stabilized clayey soils. Natural pozzolana and lime are added to soil within the range of 0%–20% and 0%–8%, respectively. Consistency, compaction, California bearing ratio (CBR) and linear shrinkage properties are particularly investigated. The test results show that the investigated properties of lime-treated clayey soils can be considerably enhanced when the natural pozzolana is added as a stabilizing agent. Analysis results of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) show significant changes in the microstructure of the treated clayey soil. A better flocculation of clayey particles and further formation of cementing materials in the natural pozzolana-lime-treated clayey soil are clearly observed. © 2016 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences
Naji A.,University of Bristol |
Naji A.,Arab International University |
Warr P.,Arab International University
IEEE Transactions on Microwave Theory and Techniques | Year: 2012
A figure of merit in characterizing resonance performance is the unloaded quality factor Q 0. Classically, this figure is calculated for planar microwave resonators in the same manner it is calculated for any arbitrary structure, by finding the electromagnetic field equations of the resonant mode and substituting them into volume and surface integrals across the concerned resonating structure. It had been observed in the literature, however, that the calculation results for some planar cases would be surprising in that the fields' modal functions (which are governed by the structure's shape) had no bearing on the value of Q 0. It is shown in this paper, using simple electromagnetic analysis, that any planar resonator that does not exhibit considerable power loss to radiation will have its Q 0 independent from its shape, and that becomes a characteristic feature of such planar resonators. The paper presents the model predicting the Q 0 for such resonators, and it shows that Q 0 only depends on the resonant frequency, on the substrate materials height, and on losses in the materials used to construct the resonating structure. Only when significant power is allowed to radiate out of the structure does the Q 0 become dependent on shape (as shape usually controls radiation). While radiation or housing power loss calculations are often complex to perform, this theory also provides a simple and accurate method of estimating such losses. In addition to its theoretical importance, this result carries an important feature for practical design as it offers flexibility in choosing shapes for planar resonators, to achieve a required value of Q 0 at a certain frequency (wavelength) and using a given set of materials. © 1963-2012 IEEE.
Ali B.,Arab International University |
Sadek M.,Lille University of Science and Technology
Arabian Journal of Geosciences | Year: 2013
The use of rubber pavement technology, also known as ecological pavement, offers a solution to a problem of worldwide dimensions. The rubber-modified asphalt becomes an excellent alternative compared to conventional asphalt. A series of laboratory tests was conducted to evaluate the effect of tire rubber addition on the performance of asphalt and asphalt concrete produced in Syria. The paper is composed of three parts: the first part includes a literature review on asphalt aging and the use of modified rubber asphalt in pavement road applications. The second part emphasizes rheological properties of two types of Syrian asphalt hard and soft and analyzes the influence of short-term aging on each type of asphalt. The last part presents a comparison of properties obtained for both cases of nonmodified asphalt and crumb rubber-modified asphalt that have been subjected to short-term aging. Results show an improvement of the resistance to short-term aging for the crumb rubber-modified asphalt. It also demonstrates that adding tire rubber to asphalt improves the performance of asphalt concrete by increasing its stability and reducing permanent deformations. © 2011 Saudi Society for Geosciences.
Al-Swaidani A.M.,Arab International University
CONCREEP 2015: Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures - Proceedings of the 10th International Conference on Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures | Year: 2015
Use of blended cements is growing rapidly in the construction industry due to economical, ecological and technical benefits. Syria is relatively rich in volcanic scoria. In the study, three types of cement were prepared; one plain Portland cement CEM I (control) and two blended cements: CEM II/A-P and CEM II/B-P (EN 197-1), each of them with three replacement levels of scoria: (10%, 15%, 20%) and (25%, 30%, 35%), respectively. Evaluation of sulfate resistance of mortars containing scoria-based cements was performed in accordance with ASTM C1012. Length measurements were performed up to 52 weeks after immersing the specimens into 5% Na2SO4 solution. Drying shrinkage has been evaluated using mortar bar method in accordance with ASTM C596. Lengths of mortar bars subjected to drying shrinkage were measured periodically up to 360 days. SRPC cement was employed for comparison in both tests. Test results revealed that the increase of scoria significantly improves the sulfate resistance of mortars. The expansion of scoria-based mortar bars decreased with the increase of scoria replacement level. Further, according to the expansion test results, CEM II/B-P can be used instead of SRPC in sulfate-bearing environments. The results of drying shrinkage showed that the CEM II/B-P-based mortar bars exhibited greater contraction when compared to the control mortar, especially at early ages. However, the long-term drying shrinkage of mortars was not influenced much by the addition of volcanic scoria. © ASCE.
Mahmoud A.B.,Arab International University
Business: Theory and Practice | Year: 2013
The goal of this research is to determine the dimensions of beliefs about internet advertising affecting Syrian consumers' attitudes and behaviors towards internet advertising. The results indicate that Attitudes are influenced positively by information, and entertainment; and negatively by irritation and values' corruption. Irritation positively influences consumers' behaviors of leaving websites showing the ads. Entertainment positively influences consumers' behaviors of clicking on internet ads for further information concerning advertised products. Attitude is found to fully mediate the relationships between beliefs of information, irritation, and values' corruption and the behaviors clicking on internet ads, and partially mediate the relationship between entertainment and the behaviors of clicking on internet ads. Attitudes fully mediate the relationships between beliefs of information, entertainment, and values' corruption and the behaviors of leaving websites showing the ads, and partially mediate the relationship between irritation and the behaviors of leaving websites showing the ads. This research comes to be one of the first studies to investigate Syrian consumers' beliefs about, attitudes, and behavioral responses towards internet advertising. As well as, this study provides evidence of the direct relationship between some of the beliefs about internet advertising (i.e. entertainment and irritation) and the behavioral responses towards it. © 2013 Vilnius Gediminas Technical University (VGTU) Press Technika.
Shammaa Y.,Arab International University |
Zhu D.Z.,University of Alberta
Journal of Hydraulic Engineering | Year: 2010
An experimental study was conducted to investigate the use of a temperature-control curtain in selective withdrawal from a two-layer stratified reservoir. This study focused on the case where cool water at a depth was forced to flow under the curtain. The evolution of the mean flow, the withdrawal water quality, and the mean velocity field were studied using particle image velocimetry and laser-induced fluorescence. Practical relationships were developed for predicting the withdrawal water quality and the interface height as a function of time. The structures of the flow field in both the upper and lower layers are discussed in detail. The flow in the lower layer was dominated by the recirculation eddy induced by the jet flow under the curtain and a relation between the eddy length and the interface height was obtained. Close to the intake, within about 3d (where d=intake diameter), the velocity field can be well described by the potential flow theory. Beyond 3d, however, the flow field considerably deviated from the potential flow theory due to the jet expansion and stratification. A general discussion of the results and engineering applications are also provided. © 2010 ASCE.
Rajab M.,Martin Luther University of Halle Wittenberg |
Jouma M.,Arab International University |
Neubert R.H.H.,Martin Luther University of Halle Wittenberg |
Dittgen M.,Arab International University
Drug Development and Industrial Pharmacy | Year: 2014
Context: The in vitro performance of floating mucoadhesive metformin tablets was optimized using different polymer ratios of polyvinylpyrrolidone (PVP) tamarind seed gum (TSG) and hydroxypropylmethylcellulose (HPMC). Objective: The objectives of this investigation were to investigate the combinatorial effects of PVP, TSG and HPMC; to study the work of adhesion measured on stainless steel (Wss) and on rabbit gastric mucosa (Wgm); and a comparison of hydrophilic and more hydrophobic tablets. Material and methods: In vitro performance was measured as tablet hardness (H), tablet floating lag time (FLT), time needed to release 60% of drug content (t60%), swelling thickness (S), Wss and Wgm. To compare the effects, a simplex lattice mixture design was used. Results and discussion: H, FLT, Wss and Wgm were found dependent on polymer ratio. H was increased when PVP ratio was increased. FLT, Wss and Wgm were increased when HPMC ratio was increased. The p value for the lack of fit for all models were greater than 0.05. An approximate linear correlation between Wgm and Wss was established (R 2=0.71). The tablets containing PVP resulted in larger H, shorter FLT and t60%, whereas Wss and Wgm were enhanced. Conclusion: The different in vitro performance of tablets containing different water-soluble polymers could be explained partially by the differences in the hydrophilic properties of the polymers and the ability of PVP to interact with HPMC or TSG. An equation established is used to conclude mucoadhesion based on adhesion measurements on stainless steel. © 2014 Informa Healthcare USA, Inc. All rights reserved: reproduction in whole or part not permitted.
Satti S.,Arab International University
Annals of Tropical Medicine and Public Health | Year: 2016
Isovaleric acidemia (IVA), also known as the sweaty foot syndrome, is an autosomal recessive organic acid disorder due to a defect in the mitochondrial Flavin Adenine Dinucleotide (FAD)-dependent enzyme isovaleryl CoA dehydrogenase. Acute pancreatitis as a complication has been reported. We are presenting a rare case of recurrent acute pancreatitis complicating a 9-year-old girl with IVA. She presented with repeated attacks of vomiting, severe abdominal pain, and fever since the age of 18 months. These were diagnosed as attacks of pancreatitis with high serum amylase presenting clinically as diabetic ketoacidosis. Later, she developed chronic pancreatitis which is proved by lapratomy. In the last attack, she was comatosed with fulminant sepsis and sooner the patient died. Blood sample taken during this last attack confirmed the diagnosis of IVA. An inborn error of organic acid metabolism should be considered in children with pancreatitis of unknown origin.