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Thermoelastic Property of a Semi-In nite Medium Induced by a Homogeneously Illuminating Laser Radiation
Abdallah I. A.,Hassan A. F.,Tayel I. M.
Progress in Physics , 2008,
Abstract: The problem of thermoelasticity, based on the theory of Lord and Shulman with one relaxation time, is used to solve a boundary value problem of one dimensional semi-infinite medium heated by a laser beam having a temporal Dirac distribution. The surface of the medium is taken as traction free. The general solution is obtained using the Laplace transformation. Small time approximation analysis for the stresses, displacement and temperature are performed. The convolution theorem is applied to get the response of the system on temporally Gaussian distributed laser radiation. Results are presented graphically. Concluding that the small time approximation has not affected the finite velocity of the heat conductivity.
Diagnosis System Based on Wavelet Transform, Fractal Dimension and Neural Network
Abdallah M. El-Ramsisi,Hassan A. Khalil
Journal of Applied Sciences , 2007,
Abstract: In this study we introduce a diagnosis system based on wavelet and fractal dimension for diagnose the Heart Mitral Valve Diseases. This study deals with the feature extraction from the Doppler signal waveform at heart mitral valve using ultrasound. Wavelet packet transforms, Fourier transform and Fractal Dimension methods are used for feature extraction from the DHS signals. The back-propagation neural network is used to classify the extracted features. The system has been evaluated in 162 samples that contain 89 normal and 73 abnormal. The results showed that the classification was about 91% for normal and abnormal cases.
Toxicity, distribution, accumulation and cooking loss of malathion in tissues of tilapia and common carp fishes
Hassan, I. M.,Abdallah, M. A.,Naguib, M. M.,Abou Donia, M. A.
Grasas y Aceites , 1993,
Abstract: The acute toxicity of malathion as an organophosphorus pesticide to both of the tested fish species, i.e. Tilapia nilotica (tilapia) and cyprinus carpio (Common carp) was followed by estimating the LC50 at intervals from 24h up to 96h. Tilapia was much more susceptible to malathion toxicity when compared with carp and the available data proved that the LG50 of malathion to common carp fish was 5-7 times the LC50 for tilapia. Accumulation of malathion pesticide in some organs (muscles, gills, intestine and liver) of both fish species was studied after application of 200, 300 and 400 ppb malathion in water for 28 days. A proportional relation was found in the two fish species between exposure time and the applied concentrations. The rate of malathion accumulation was higher in liver followed by intestine and gills whereas the lowest concentration was found in muscles. Accumulated malathion in tilapia muscles was higher than carp; while a reversible trend was observed in most other organs. Cooking of the same fish species reduced effectively malathion content in their muscles. Frying of fish in oil lead to a higher loss percent of malathion than did the other methods of cooking. La toxicidad aguda de malatión, pesticida organofosforado, para las dos especies de pescado analizadas, Tilapia nilotica (tilapia) y Cyprinus carpio (carpa común), fue seguida por estimación de la CL50 a intervalos desde las 24h hasta las 96h. Tilapia fue mucho más susceptible a la toxicidad del malatión cuando se comparó con carpa, y los datos disponibles proporcionaron que la CL50 del malatión para carpa común fue de 5-7 veces la GL50 para tilapia. La acumulación del pesticida malatión en algunos órganos (músculos, agallas, intestino e hígado) de ambas especies de pescado fue estudiada después de la aplicación de concentraciones de 200, 300 y 400 ppb de malatión en agua durante 28 días. Se encontró una relación proporcional entre el tiempo de exposición y las concentraciones aplicadas en las dos especies de pescado. La velocidad de acumulación de malatión fue alta en hígado, seguido por intestino y agallas, mientras que la concentración más baja fue encontrada en músculos. El malatión acumulado en músculos de tilapia fue superior al acumulado en los de carpa, mientras que una tendencia reversible fue observada en la mayoría de los otros órganos. El cocinado de algunas especies de pescado redujo eficazmente el contenido de malatión en sus músculos. La fritura de pescado en aceite condujo a un mayor porcentaje de pérdida de malatión que con otros métodos de cocinado.
Chemical Reaction of Soybean Flavonoids with DNA: A Computational Study Using the Implicit Solvent Model
Hassan H. Abdallah,Janez Mavri,Matej Repi?,Vannajan Sanghiran Lee,Habibah A. Wahab
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms13021269
Abstract: Genistein, daidzein, glycitein and quercetin are flavonoids present in soybean and other vegetables in high amounts. These flavonoids can be metabolically converted to more active forms, which may react with guanine in the DNA to form complexes and can lead to DNA depurination. We assumed two ultimate carcinogen forms of each of these flavonoids, diol epoxide form and diketone form. Density functional theory (DFT) and Hartree-Fock (HF) methods were used to study the reaction thermodynamics between active forms of flavonoids and DNA guanine. Solvent reaction field method of Tomasi and co-workers and the Langevin dipoles method of Florian and Warshel were used to calculate the hydration free energies. Activation free energy for each reaction was estimated using the linear free energy relation. Our calculations show that diol epoxide forms of flavonoids are more reactive than the corresponding diketone forms and are hence more likely flavonoid ultimate carcinogens. Genistein, daidzein and glycitein show comparable reactivity while quercetin is less reactive toward DNA.
The case for conducting first-in-human (phase 0 and phase 1) clinical trials in low and middle income countries
Lydia Kapiriri, James V Lavery, Peter A Singer, Hassan Mshinda, Lorne Babiuk, Abdallah S Daar
BMC Public Health , 2011, DOI: 10.1186/1471-2458-11-811
Abstract: There are scientific and pragmatic arguments that support conducting FIH trials in LMIC. Furthermore, the changing product-development and regulatory landscape, and the likelihood of secondary benefits such as capacity building for innovation and for research ethics support our argument. These arguments take into account the critical importance of protecting human subjects of research while developing capacity to undertake FIH trials.While FIH trials have historically not been conducted in LMICs, the situation in some of these countries has changed. Hence, we have argued that FIH should be conducted in LMICs for products meant primarily for conditions that are most prevalent in those contexts; provided the necessary protections for human subjects are sufficient.Despite the sustained proliferation of clinical trials in low and middle income countries (LMICs), [1] there has been little examination of whether First in Human (FIH; phase 0 and phase 1) clinical trials should be conducted in LMICs, and if so, under what conditions. Most of the discussion has focused on later phases of clinical trials. The purpose of this paper is to stimulate debate on the merits of FIH trials in LMICs: the default option should be to do the trials where the relevant health conditions present the greatest public health challenge, if, and only if, the necessary capacities exist for participant safety and scientific rigor. We argue, further, that the default presumptions against performing FIH trials in LMICs may be quietly impeding progress in the evolution of the very capacities that these trials require.Interest in FIH clinical trials has grown recently, in part because of the disastrous experience of the phase I clinical trial of the superagonistic anti-CD28 antibody TGN1412 in the United Kingdom. The drug was developed with the intention to stimulate a specific kind of T-cell while at the same time controlling the production of other T-cells in order to suppress the immune system. In t
1,3-Bis[(3-allylimidazol-3-ium-1-yl)methyl]benzene bis(hexafluoridophosphate)
Rosenani A. Haque,Mohammed Z. Ghdhayeb,Hassan H. Abdallah,Ching Kheng Quah
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536810050683
Abstract: In the title compound, C20H24N42+·2PF6 , the ethene and 3-allylimidazolium moieties of the cation are disordered over two positions with refined site occupancies of 0.664 (19):0.336 (19) and 0.784 (7):0.216 (7), respectively, whereas four F atoms of one hexafluoridophosphate anion and all atoms in the other hexafluoridophosphate anion are disordered over two positions with refined site occupancies of 0.764 (5):0.2365) and 0.847 (9):0.153 (9), respectively. The benzene ring is inclined at angles of 78.2 (3), 81.3 (4) and 73.9 (12)° with the 1H-imidazol-3-ium ring and the major and minor components of the disordered 1H-imidazol-3-ium ring, respectively. In the crystal, the hexafluoridophosphate anions link the cations into two-dimensional networks parallel to (001) via intermolecular C—H...F hydrogen bonds. The crystal structure is further consolidated by π–π [centroid–centroid distance = 3.672 (3) ] and C—H...π interactions.
An Inverse Finite Element Method for Determining the Tissue Compressibility of Human Left Ventricular Wall during the Cardiac Cycle
Abdallah I. Hassaballah, Mohsen A. Hassan, Azizi N. Mardi, Mohd Hamdi
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0082703
Abstract: The determination of the myocardium’s tissue properties is important in constructing functional finite element (FE) models of the human heart. To obtain accurate properties especially for functional modeling of a heart, tissue properties have to be determined in vivo. At present, there are only few in vivo methods that can be applied to characterize the internal myocardium tissue mechanics. This work introduced and evaluated an FE inverse method to determine the myocardial tissue compressibility. Specifically, it combined an inverse FE method with the experimentally-measured left ventricular (LV) internal cavity pressure and volume versus time curves. Results indicated that the FE inverse method showed good correlation between LV repolarization and the variations in the myocardium tissue bulk modulus K (K = 1/compressibility), as well as provided an ability to describe in vivo human myocardium material behavior. The myocardium bulk modulus can be effectively used as a diagnostic tool of the heart ejection fraction. The model developed is proved to be robust and efficient. It offers a new perspective and means to the study of living-myocardium tissue properties, as it shows the variation of the bulk modulus throughout the cardiac cycle.
Mapping the Potential Risk of Mycetoma Infection in Sudan and South Sudan Using Ecological Niche Modeling
Abdallah M. Samy ,Wendy W. J. van de Sande,Ahmed Hassan Fahal,A. Townsend Peterson
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0003250
Abstract: In 2013, the World Health Organization (WHO) recognized mycetoma as one of the neglected tropical conditions due to the efforts of the mycetoma consortium. This same consortium formulated knowledge gaps that require further research. One of these gaps was that very few data are available on the epidemiology and transmission cycle of the causative agents. Previous work suggested a soil-borne or Acacia thorn-prick-mediated origin of mycetoma infections, but no studies have investigated effects of soil type and Acacia geographic distribution on mycetoma case distributions. Here, we map risk of mycetoma infection across Sudan and South Sudan using ecological niche modeling (ENM). For this study, records of mycetoma cases were obtained from the scientific literature and GIDEON; Acacia records were obtained from the Global Biodiversity Information Facility. We developed ENMs based on digital GIS data layers summarizing soil characteristics, land-surface temperature, and greenness indices to provide a rich picture of environmental variation across Sudan and South Sudan. ENMs were calibrated in known endemic districts and transferred countrywide; model results suggested that risk is greatest in an east-west belt across central Sudan. Visualizing ENMs in environmental dimensions, mycetoma occurs under diverse environmental conditions. We compared niches of mycetoma and Acacia trees, and could not reject the null hypothesis of niche similarity. This study revealed contributions of different environmental factors to mycetoma infection risk, identified suitable environments and regions for transmission, signaled a potential mycetoma-Acacia association, and provided steps towards a robust risk map for the disease.
A Modified Limberg Flap versus Z Plasty Flap Technique in Management of Recurrent Pilonidal Disease: A Comparative Prospective Study  [PDF]
Asmaa Gaber R., Mohamed Yousef A., Mohamed Abdel Shafy Mohamed, Abd-El-Aal A. Saleem, Hassan A. Abdallah, Hamdy M. Husein
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104715
Abstract:
Background: There are controversies about the etiology and management of recurrent pilonidal sinus. The numbers of techniques are testament in treating pilonidal sinus (PNS) and no single procedure is superior in all aspects. Aim of the study: The aim of this study was to compare two operative procedures (modified Limberg flap versus Z plasty flap) in management of recurrent pilonidal sinus, regarding their complications including recurrences of the disease, morbidity, hospital stay, day off work and postoperative complications. Patients and methods: This is comparative prospective study between modified Limberg flap and Z plasty flap in treatment of recurrent pilonidal sinus. 30 patients were divided into 2 groups: Group (1) treated with modified Limberg flap and group (2) treated with Z plasty, and we followed up the patients in both groups for postoperative complications, hospital stay, day off work, recurrences, patients satisfactions. Results: Operative time, hospital stay duration, complete wound healing was longer in group (2) Z plasty group. Mobilization was early in MLF group than Z plasty group (1 day versus 2 days). Time to return to work, it was 14 (12 - 16) days in MLF groups and 18 (15 - 22) in Z plasty group (p < 0.001). Infection occurred only in one in MLF group (1) and 2 patients in Z plasty group (2). The mean time for complete healing of the wound after Modified Limberg flap group (1) was 16 ± 4.2 days while in Z plasty group (2) it was 22 ± 6.8 days. Satisfaction score was better in MLF group (1). Recurrence hadn’t occurred in any of the patients included in this study during the follow-up period. Conclusion: Both of modified Limberg flap and Z-plasty technique are used to cause flattening of the natal cleft, thus reducing local recurrence rates. So, we recommend use of flap technique for recurrent pilonidal sinus patients; modified Limberg transposition flap is better than Z plasty flap, because of the less hospital stay time, early return to work, and cosmetically more accepted as it has less postoperative complications. Also Z plasty flap has a major limitation as it is difficult to apply if there is a wide defect in the horizontal axis.
Public engagement on global health challenges
Emma RM Cohen, Hassan Masum, Kathryn Berndtson, Vicki Saunders, Tom Hadfield, Dilzayn Panjwani, Deepa L Persad, Gunjeet S Minhas, Abdallah S Daar, Jerome A Singh, Peter A Singer
BMC Public Health , 2008, DOI: 10.1186/1471-2458-8-168
Abstract: This paper gives an overview about public engagement and related concepts, with a particular focus on challenges and benefits in the developing world. We then describe an Internet-based platform, which seeks to both inform and engage youth and the broader public on global water issues and their health impacts. Finally, we outline a possible course for future action to scale up this and similar online public engagement platforms.The benefits of public engagement include creating an informed citizenry, generating new ideas from the public, increasing the chances of research being adopted, increasing public trust, and answering ethical research questions. Public engagement also fosters global communication, enables shared experiences and methodology, standardizes strategy, and generates global viewpoints. This is especially pertinent to the developing world, as it encourages previously marginalized populations to participate on a global stage. One of the core issues at stake in public engagement is global governance of science and technology. Also, beyond benefiting society at large, public engagement in science offers benefits to the scientific enterprise itself.Successful public engagement with developing world stakeholders will be a critical part of implementing new services and technologies. Interactive engagement platforms, such as the Internet, have the potential to unite people globally around relevant health issues.The importance of engaging the public on risks and benefits of science and technology (S&T) is widely accepted. Experience with public engagement activities is growing, especially in the industrialized world. However, public engagement in the developing world regarding S&T risks and benefits to explore health issues has received relatively little attention.The purpose of this paper is to be descriptive. We will briefly review what is known about public engagement, with emphasis on biotechnology-related examples and the developing world. We will then
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