563 research outputs found

    A re-examination of the Salicornias (Amaranthaceae) of Saudi Arabia and their polymorphs

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    During the period from 1964 to 1999 Saudi Arabian species of Salicornia were wrongly treated under the European species, S. europaea L. Recent explorations proved that there are two separate allopatric species of Salicornia in Saudi Arabia, one inhabiting the inland salt-marshes of the Najd (highlands) and the other inhabiting the Arabian Gulf Coast (lowlands). Morphological, ecological and exploratory studies confirm that they are two distinct species. The two species differ in features of bark, axillary spikes, basal vegetative segment(s) of spike, fertile segments, colour of senescent plants, and flowering, fruiting and germination phenology. As both the species have been described earlier from Iran, they are now new records for Saudi Arabia. The species are, S. persica ssp. iranica (Akhani) Kadereit & Piirainen and S. sinus-persica Akhani. S. sinus-persica, of which the status was thought doubtful has been confirmed. Both the species have been described and illustrated. Each species comprises a number of polymorphs. As leaves and flowers are rudimentary, confusing species circumscriptions, a proliferation of binomials has resulted in the taxonomy of Salicornia. To mitigate such confusion, the full range of variability of the Saudi Arabian species has been documented

    Determination of Seed Viability of Eight Wild Saudi Arabian Species by Germination and X-Ray Tests

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    Our purpose was to evaluate the usefulness of the germination vs. the X-ray test in determining the initial viability of seeds of eight wild species (Salvia spinosa, Salvia aegyptiaca, Ochradenus baccatus, Ochradenus arabicus, Suaeda aegyptiaca, Suaeda vermiculata, Prosopisfarcta and Panicumturgidum) from Saudi Arabia. Several days were required to determine viability of all eight species via germination tests, while immediate results on filled/viable seeds were obtained with the X-ray test. Seeds of all the species, except Sa.aegyptiaca, showed high viability in both the germination (98–70% at 25/15 °C, 93–66% at 35/25 °C) and X-ray (100–75%) test. Furthermore, there was general agreement between the germination (10% at 25/15 °C and 8% at 35/25 °C) and X-ray (5%) tests that seed viability of Sa.aegyptiaca was very low, and X-ray analysis revealed that this was due to poor embryo development. Seeds of P.farcta have physical dormancy, which was broken by scarification in concentrated sulfuric acid (10 min), and they exhibited high viability in both the germination (98% at 25/15 °C and 93% at 35/25 °C) and X-ray (98%) test. Most of the nongerminated seeds of the eight species except those of Sa.aegyptiaca were alive as judged by the tetrazolium test (TZ). Thus, for the eight species examined, the X-ray test was a good and rapid predictor of seed viability

    Bilateral acute angle closure glaucoma after hyperopic LASIK correction

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    AbstractAcute angle closure glaucoma is unexpected complication following laser in situ keratomileusis (LASIK). We are reporting a 49-years-old lady that was presented to the emergency department with acute glaucoma in both eyes soon after LASIK correction. Diagnosis was made on detailed clinical history and examination, slit lamp examination, intraocular pressure measurement and gonioscopy. Laser iridotomy in both eyes succeeded in controlling the attack and normalizing the intraocular pressure (IOP) more than 6months of follow-up. Prophylactic laser iridotomy is essential for narrow angle patients before LASIK surgery if refractive laser surgery is indicated

    Genetic Influence of Candidate Osteoporosis Genes in Saudi Arabian Population: A Pilot Study

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    Background and Objectives. The purpose of the present study is to find the genes and SNP that influence BMD and postmenopausal Saudi women. Material and Methods. Two-hundred ethnic Saudi Arabian women with a diagnosis of postmenopausal osteoporosis were the subjects of this study. Baseline blood hematology, biochemistry, and bone panel were done. Blood was collected, and three TaqMan-MGB probes were used to analyze SNP variants in ALOX15 (rs7220870), LRP5 (C 25752205 10), and TNFRSF11B (C 11869235 10). Results. The variant of ALOX15 17p13 showed that the BMD of the spine was lower in the AA allele (P value <0.002) and fractures were highest at 50% compared to CC allele. In the TNFRSF11B gene, BMD of the hip and spine was significantly higher in the GG allele and the history of fractures was significantly higher in GG group. With regard to the LRP5 (C 25752205 10) gene, there was no significant difference between allele groups. Conclusion(s). This study shows that the genetic influence of osteoporosis in the Caucasian and Saudi Arabians population is similar. We believe that the same genetic markers that influence osteoporosis in the Caucasian race could be used for further studies in the Saudi Arabian population

    Flow injection analysis of some oxidants using spectrophotometric detection

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    AbstractA spectrophotometric flow-injection method has been devised for the determination of nanomole quantities of some oxidants i.e. iodate, periodate, permanganate and hydrogen peroxide. The method is based on the oxidation of iron(II) to iron(III) and the measurement of the absorbance of the red iron(III)–thiocyanate complex at 485nm. The optimal oxidation pH and the linearity ranges of the calibration curves have been investigated. The analytical aspects of the method including the statistical evaluation of the results are discussed. The analysis of some authentic samples showed an average percentage recovery of 99%

    Synthesis and Characterization of Some New Dianiline Oxide Derivatives

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    Multifunctional dianiline oxide ligands from 1,3-indanedione with aniline derivatives in ethanol (abs.) then with hydrogen peroxide in gl acial acetic acid  (Scheme 1) were synthesized. These dianiline oxide  compounds have been characterized by C, H, N elemental analysis, FT-IR, and 1H NMR spectroscopy. Keywords: aniline oxide , indanedione, nitron

    Optimization of Fuzzy Logic Controller for Supervisory Power System Stabilizers

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    This paper presents a powerful supervisory power system stabilizer (PSS) using an adaptive fuzzy logic controller driven by an adaptive fuzzy set (AFS). The system under study consists of two synchronous generators, each fitted with a PSS, which are connected via double transmission lines. Different types of PSS-controller techniques are considered. The proposed genetic adaptive fuzzy logic controller (GAFLC)-PSS, using 25 rules, is compared with a static fuzzy logic controller (SFLC) driven by a fixed fuzzy set (FFS) which has 49 rules. Both fuzzy logic controller (FLC) algorithms utilize the speed error and its rate of change as an input vector. The adaptive FLC algorithm uses a genetic algorithmto tune the parameters of the fuzzy set of each PSS. The FLC’s are simulated and tested when the system is subjected to different disturbances under a wide range of operating points. The proposed GAFLC using AFS reduced the computational time of the FLC, where the number of rules is reduced from 49 to 25 rules. In addition, the proposed adaptive FLC driven by a genetic algorithm also reduced the complexity of the fuzzy model, while achieving a good dynamic response of the system under study

    Optimization of Fuzzy Logic Controller for Supervisory Power System Stabilizers

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    This paper presents a powerful supervisory power system stabilizer (PSS) using an adaptive fuzzy logic controller driven by an adaptive fuzzy set (AFS). The system under study consists of two synchronous generators, each fitted with a PSS, which are connected via double transmission lines. Different types of PSS-controller techniques are considered. The proposed genetic adaptive fuzzy logic controller (GAFLC)-PSS, using 25 rules, is compared with a static fuzzy logic controller (SFLC) driven by a fixed fuzzy set (FFS) which has 49 rules. Both fuzzy logic controller (FLC) algorithms utilize the speed error and its rate of change as an input vector. The adaptive FLC algorithm uses a genetic algorithmto tune the parameters of the fuzzy set of each PSS. The FLC’s are simulated and tested when the system is subjected to different disturbances under a wide range of operating points. The proposed GAFLC using AFS reduced the computational time of the FLC, where the number of rules is reduced from 49 to 25 rules. In addition, the proposed adaptive FLC driven by a genetic algorithm also reduced the complexity of the fuzzy model, while achieving a good dynamic response of the system under study

    Design, synthesis, molecular modeling and biological evaluation of novel diaryl heterocyclic analogs as potential selective cyclooxygenase-2 (COX-2) inhibitors

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    AbstractNew series of 3,4-diaryl-2-thioxoimidazolidin-4-ones and 3-alkylthio-4,5-diaryl-4H-1,2,4-triazoles were designed, synthesized and evaluated for their activity as anti-inflammatory agents. Compounds 20, 21, 23 and 34 are highly selective inhibitors of COX-2 enzyme at a concentration of 100mM relative to celecoxib, the standard reference. (±)-3-(4-Phenoxy-phenyl)-5-phenyl-2-thioxoimidazolidin-4-ones 23 exhibited the most active anti-inflammatory agent

    Diversity and distribution of dipterous flies of medical and veternary importance in Tayma, Saudi Arabia

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    The present study aims to investigate the distribution and diversity of dipterous flies in Tayma (Saudi Arabia) during the spring of 2018. A total of 12 dipterous species were collected from three different sites located in Tayma (Tabuk, Saudi Arabia) located in the Northern part of Saudi Arabia. The taxa of flies were dominated by Musca domestica and Musca sorbens. No significant difference were observed between the total number of flies collected using different traps (t-test, P0.05) and among the studied sites (ANOVA, P0.05). The highest number of flies was recorded from Site 3 (a cattle farm). However, lower number of flies was reported from the dates palm farms. In conlusion, the species Musca domestica were found to be the most abundant species in all locations with remarkable high abundance in animal facilities (slaughter house and animal farm). The pheromone traps were found to be the most effective trap catching high number of individuls and high number of fly species.
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