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Search Results: 1 - 10 of 4382 matches for " Omar Deeb "
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Exploring QSARs for Inhibitory Activity of Cyclic Urea and Nonpeptide-Cyclic Cyanoguanidine Derivatives HIV-1 Protease Inhibitors by Artificial Neural Network  [PDF]
Omar Deeb, Mohammad Jawabreh
Advances in Chemical Engineering and Science (ACES) , 2012, DOI: 10.4236/aces.2012.21010
Abstract: Quantitative structure–activity relationship study using artificial neural network (ANN) methodology were conducted to predict the inhibition constants of 127 symmetrical and unsymmetrical cyclic urea and cyclic cyanoguanidine derivatives containing different substituent groups such as: benzyl, isopropyl, 4-hydroxybenzyl, ketone, oxime, pyrazole, imidazole, triazole and having anti-HIV-1 protease activities. The results obtained by artificial neural network give advanced regression models with good prediction ability. The two optimal artificial neural network models obtained have coefficients of determination of 0.746 and 0.756. The lowest prediction’s root mean square error obtained is 0.607. Artificial neural networks provide improved models for heterogeneous data sets without splitting them into families. Both the external and cross-validation methods are used to validate the performances of the resulting models. Randomization test is employed to check the suitability of the models.
Ghost cohomologies and new discrete states in supersymmetric c=1 model
Omar El Deeb
Physics , 2014,
Abstract: As of today, string theory appears to be one of the most promising physical models unifying the fundamental interactions in nature, such as electromagnetic (gauge) interactions and the gravity. While the perturbative theory of strings appears to be well explored by now, we still lack an adequate formulation of string-theoretic formalism in the non-perturbative, or strongly coupled regime. One of the approaches, allowing us to explore the non-perturbative dynamics of strings (as well as of other physical theories with gauge degrees of freedom) is the formalism of ghost cohomologies, studied in this thesis. This approach is based on the fact that virtually all the crucial information on non-perturbative physics of gauge theories,but not manifestly gauge-invariant. Typically, these operators belong to a very special sector of the Hilbert space of gauge theories, where the matter and the ghost degrees of freedom are mixed. These physical operators are defined as elements of ghost cohomologies, studied in this thesis. In this work, we explore the formalism of ghost cohomologies on the example of supersymmetric c = 1 model which is one of the simplist models of superstrings, with elegant and transparent structure of the spectrum of physical states (vertex operators). We show how the presence of the ghost cohomologies enlarges the spectrum of states and leads to new intriguing symmetries of the theory and points to possible nontrivial relations of two-dimensional supergravity to physical theories in higher dimensions. We also develop general prescription for constructing BRST -invariant and nontrivial vertex operators.
Exploring MIA-QSARs for farnesyltransferase inhibitory effect of antimalarial compounds refined by docking simulations  [PDF]
Omar Deeb, Sherin Alfalah, Matheus P. Freitas, Elaine F. F. da Cunha, Teodorico C. Ramalho
Journal of Biophysical Chemistry (JBPC) , 2012, DOI: 10.4236/jbpc.2012.31008
Abstract: Two series of farnesyltransferase (FTase) inhibitors were grouped and their antimalarial activi-ties modeled by means of multivariate image analysis applied to quantitative structure-activity relationship (MIA-QSAR). A reliable model was achieved, with r2 for calibration, external prediction and leave-one-out cross-validation of 0.96, 0.87 and 0.83, respectively. Therefore, biological activities of congeners can be estimated using the QSAR model. The bioactivities of new compounds based on the miscellany of substructures of the two classes of FTase inhibitors were predicted using the MIA-QSAR model and the most promising ones were submitted to ADME (absorption, distribution, metabolism and excretion) and docking evaluation. Despite the smaller interaction energy of the two most promising, predicted compounds in comparison to the two most active compounds of the data set, one of the proposed structures did not violate any Lipinski’s rule of five. Therefore, it is either a potential drug or may drive synthesis of similar, improved compounds.
QSPR Modeling of Bioconcentration Factors of Nonionic Organic Compounds
Omar Deeb, Padmakar V. Khadikar and Mohammad Goodarzi
Environmental Health Insights , 2012, DOI: 10.4137/EHI.S5168
Abstract: The terms bioaccumulation and bioconcentration refer to the uptake and build-up of chemicals that can occur in living organisms. Experimental measurement of bioconcentration is time-consuming and expensive, and is not feasible for a large number of chemicals of potential regulatory concern. A highly effective tool depending on a quantitative structure-property relationship (QSPR) can be utilized to describe the tendency of chemical concentration organisms represented by, the important ecotoxicological parameter, the logarithm of Bio Concentration Factor (log BCF) with molecular descriptors for a large set of non-ionic organic compounds. QSPR models were developed using multiple linear regression, partial least squares and neural networks analyses. Linear and non-linear QSPR models to predict log BCF of the compounds developed for the relevant descriptors. The results obtained offer good regression models having good prediction ability. The descriptors used in these models depend on the volume, connectivity, molar refractivity, surface tension and the presence of atoms accepting H-bonds.
QSPR Modeling of Bioconcentration Factors of Nonionic Organic Compounds
Omar Deeb,Padmakar V. Khadikar,Mohammad Goodarzi
Environmental Health Insights , 2010,
Abstract:
Qualification of Soft Costs of the US Federal Guidance When Considering Greenhouse Gas Emissions and the Effects of Climate Change in NEPA Reviews  [PDF]
Maria Angelica Deeb
Journal of Geoscience and Environment Protection (GEP) , 2015, DOI: 10.4236/gep.2015.36010
Abstract:

A notice by the Council of Environmental Quality (CEQ) was published on December 14, 2014 regarding the revised “Draft Guidance for Federal Departments and Agencies on Consideration of Greenhouse Gas Emissions and the Effects of Climate Change in NEPA Reviews”. The review of this 2014 draft guidance suggested increased analysis, work, review and approvals required by the State Department of Transportation (DOT) and Federal Highway Administration (FHWA) working with and on behalf of local public agencies (LPAs) in order to authorize and obligate roadway projects funded with federal-aid money. All federal-aid-funded roadway projects require a NEPA analysis to be done on the action (project) and an environmental clearance document to be obtained prior to finalizing the design. The 2014 draft guidance may complicate an already lengthy and often critical path activity for roadway projects requiring NEPA documentation.

Lethal time at different temperatures and date variety preference of the saw-toothed grain beetle in stored dates  [PDF]
Mohammad Ali Al-Deeb
Agricultural Sciences (AS) , 2012, DOI: 10.4236/as.2012.36095
Abstract: This electronic document is a “live” template. The various The saw-toothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), is the most important insect pest attacking stored dates in the United Arab Emirates. We sought to determine the time required to cause 100% mortality (lethal time) in O. surinamensis adults incubated at different temperatures, to measure temperature penetration time inside a date mass, and to study date variety preference of O. surinamensis adults. To do this, adults of O. surinamensis were separately incubated at -22℃, 50℃, and 55℃, for 5, 10, 20, 30, 60, 90, and 120 min, per temperature treatment; and we used feeding choice tests on four date varieties (Khelas, Fardh, Lulu, and BuMaán). Results showed that the lethal times of O. surinamensis adults, incubated at -22℃, 50℃, and 55℃, without dates, were 5, 10, and 20 min, respectively; while they were several times higher (30, 90, and 120 min, respectively) in the presence of dates. Results also showed that bigger date masses required either more heating or more freezing time to reach lethal temperatures. We found Khelas to be the least preferred date variety. Future studies should evaluate if heat and chilling injury affect postharvest date quality.
Pyrethroid Insecticide Resistance kdr Gene in the House Fly, Musca domestica (Diptera: Muscidae), in the United Arab Emirates  [PDF]
Mohammad Ali Al-Deeb
Agricultural Sciences (AS) , 2014, DOI: 10.4236/as.2014.514163
Abstract: The house fly, Musca domestica L., is a very important insect because of its role as a vector of several human, livestock, and poultry diseases. Different groups of insecticides, including the pyrethroids, are used to control house flies. The objective of the current study was to conduct a survey of the kdr insecticide resistance gene in the house fly population in the United Arab Emirates (UAE). Flies were collected from five locations (Abu Dhabi, Dubai, Fujairah, Ajman, and Ras Al- Khaymah). Genomic DNA was extracted and polymerase chain reaction (PCR) amplification of specific allele (PASA) was performed. The maximum percentage (70%) of homozygous genotype (kdr/kdr) occurred at Ajman, followed by Dubai (59.5%), and the minimum percentage occurred at Ras Al-Khaymah (14.3%). Resistant insects of the genotype kdr/kdr were detected in all of the tested house fly populations. Ajman and Fujairah house fly populations were in Hardy-Weinberg equilibrium. The resistance kdr allele was found at a high frequency (0.54 - 0.8) at all locations except at Ras Al-Khaymah (0.21). Together, this study demonstrated that the pyrethroid insecticide resistance kdr allele was found in UAE house fly populations, strongly suggesting that a countrywide pyrethroid insecticide resistance management program needs to be implemented.
Synthesis and Antimicrobial Activity of Some Novel 5-Alkyl-6-Substituted Uracils and Related Derivatives
Abdulghafoor A. Al-Turkistani,Omar A. Al-Deeb,Nasser R. El-Brollosy,Ali A. El-Emam
Molecules , 2011, DOI: 10.3390/molecules16064764
Abstract: 6-Chloro-5-ethyl-, n-propyl- and isopropyluracils 5a-c were efficiently prepared from the corresponding 5-alkybarbituric acids 3a-c via treatment with phosphorus oxychloride and N,N-dimethylaniline to yield the corresponding 5-alkyl-2,4,6-trichloro-pyrimidines 4a-c, which were selectively hydrolyzed by heating in 10% aqueous sodium hydroxide for 30 minutes. The reaction of compounds 5a-c with 1-substituted piperazines yielded the corresponding 5-alkyl-6-(4-substituted-1-piperazinyl)uracils 6a-j. The target 8-alkyltetrazolo[1,5-f]pyrimidine-5,7(3H,6H)-diones 7a-c were prepared via the reaction of 5a-c with sodium azide. Compounds 6a-j and 7a-c were tested for in vitro activities against a panel of Gram-positive and Gram-negative bacteria and the yeast-like pathogenic fungus Candida albicans. Compound 6h displayed potent broad-spectrum antibacterial activity, while compound 6b showed moderate activity against the Gram-positive bacteria. All the tested compounds were practically inactive against Candida albicans.
2-[(4-Chlorobenzyl)sulfanyl]-4-(2-methylpropyl)-6-[3-(trifluoromethyl)anilino]pyrimidine-5-carbonitrile
Ali A. El-Emam,Omar A. Al-Deeb,Nasser R. El-Brollosy,Seik Weng Ng
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812025895
Abstract: Three independent molecules comprise the asymmetric unit of the title compound, C23H20ClF3N4S. The conformations of the molecules are similar with the chlorobenzene and CF3-benzene rings almost perpendicular to, and almost co-planar with, the pyrimidinyl ring [range of dihedral angles = 80.36 (13)–88.07 (14) and 11.89 (14)–23.30 (14)°, respectively]; the benzene rings are roughly orthogonal to each other [64.81 (16)–72.16 (15)°]. In the crystal, two of the independent molecules associate via weak N—H...N(cyano) hydrogen bonds and 12-membered {...HNC3N}2 synthons; the third independent molecule self-associates similarly but about a centre of inversion. The sample studied was found to be a non-merohedral twin and the minor twin component refined to 47.16 (7)%.
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