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Thermal Effects On The Body Mass, Transpiration Rate, Feeding And Food Conversion Of The Pillbug Armadillo Officinalis (Isopoda, Oniscidea) Fed On The Dry Leaf Of Punica Granatum, Abdelgader K. Youssef, Achuthan Nair Apr 2025

Thermal Effects On The Body Mass, Transpiration Rate, Feeding And Food Conversion Of The Pillbug Armadillo Officinalis (Isopoda, Oniscidea) Fed On The Dry Leaf Of Punica Granatum, Abdelgader K. Youssef, Achuthan Nair

Sultan Qaboos University Journal For Science

Observations were made on the body mass; transpiration rate; assimilation efficiency; gross and net production efficiencies; feeding, assimilation, conversion and metabolic rates of the pillbug Armadillo officinalis Dumeril acclimatized at 14º and 21 °C for 15 days and fed on the dry leaf of Punica granatum (Pomegranate). A brief description is given on the chemical composition of P. granatum leaf. The difference in body mass increments of A. officinalis between the acclimatized temperatures was not significant (t = 1.09; p>0.05). However, significant differences were discernible on the transpiration rate (t = 9.53; p<0.01), moisture (t = 9.01; p<0.01), assimilation efficiency (t = 5.16; p<0.01), feeding (t = 3.76; p<0.05) and conversion (t = 2.58; p<0.05) rates between the woodlice acclimatized at 14º and 21 °C. Better feeding of P. granatum leaf by these animals was observed at 21° C, but better assimilation efficiency at 14 °C. Only 3.21% assimilated food at 14° C and 6.30% at 21 °C were converted into the production of new tissues. The food consumption of A. officinalis at 14º and 21° C was 2.05% and 3.79% body mass/day respectively. The effect of temperature on the activity of A. officinalis in the field is discussed.

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Isolation Of Aristolochic Acids From Aristolochia Bracteolata And Studies Of Their Antioxidant Activities, Saleh Al-Busafi, Munir Al-Harthi, Bushra Al-Sabahi Apr 2025

Isolation Of Aristolochic Acids From Aristolochia Bracteolata And Studies Of Their Antioxidant Activities, Saleh Al-Busafi, Munir Al-Harthi, Bushra Al-Sabahi

Sultan Qaboos University Journal For Science

The isolation and structural elucidation of aristolochic acid-A and aristolochic acid-D from Omani Aristolochia bracteolata plant is reported. Antioxidant activities of these two natural products were evaluated for their capacity to reduce Mo(VI) to Mo(V). The study revealed that aristolochic acid-D is more active than vitamin C while aristolochic acid-A has activity similar to vitamin C.

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Xanthotoxin And Other Furanocoumarins As Phytoalexins In Pastinaca Sativa L. Roots, Fatma M. Al-Barwani, Elsadig A. Eltayeb Apr 2025

Xanthotoxin And Other Furanocoumarins As Phytoalexins In Pastinaca Sativa L. Roots, Fatma M. Al-Barwani, Elsadig A. Eltayeb

Sultan Qaboos University Journal For Science

Our results confirm the presence of the furanocoumarins psoralen, xanthotoxin, isopimpinellin, angelicin and bergapten as normal constituents of Pastinaca sativa roots. However, the amounts of these compounds were increased in induced roots. The amount of increase in the induced roots varied depending on the inducing agent and time of incubation. In addition the results show for the first time the presence of pimpinellin and isobergapten as constitutive antifungal compounds in P. sativa roots.

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Solution Of A Nonlinear Functional Equation, Valery C. Covachev, H. Ali Yurtsever Apr 2025

Solution Of A Nonlinear Functional Equation, Valery C. Covachev, H. Ali Yurtsever

Sultan Qaboos University Journal For Science

In the present paper a generalization of a theorem of I.B. Risteski (2004) concerning the solution of a nonlinear functional equation is given. The proof is based on a parametric approach by introducing a parameter in an arbitrary set , and on a matrix method for solving linear functional equations.

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Recursive Estimation Of A Discrete-Time Lotka-Volterra Predator-Prey Model, Lakhdar Aggoun Apr 2025

Recursive Estimation Of A Discrete-Time Lotka-Volterra Predator-Prey Model, Lakhdar Aggoun

Sultan Qaboos University Journal For Science

In this paper, using hidden Markov models, we estimate the number of individuals in a two-species (predator-prey) animal population using partial information provided by the so-called capture-recapture technique. Random samples of individuals are captured, tagged in some way and released. After some time other random samples are taken and the marked individuals are observed. Using this information, we estimate (recursively) the sizes of the two populations. Also, using the Expectation Maximization (EM) algorithm, the parameters of the model are updated.

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Some Aspects Of The Anatomy And Histology Of Digestive Tracts In Two Sympatric Species Of Freshwater Fishes, Taher Ba-Omar, Reginald Victor, Daniel Tobias Apr 2025

Some Aspects Of The Anatomy And Histology Of Digestive Tracts In Two Sympatric Species Of Freshwater Fishes, Taher Ba-Omar, Reginald Victor, Daniel Tobias

Sultan Qaboos University Journal For Science

Comparative anatomy and histology of the digestive tracts of two sympatric species of freshwater fish, Aphanius dispar (Cyprinodontidae) and Garra barreimiae (Cyprinidae) are studied. Morphometric measurements of alimentary canal such as length and the number and height of rugae in sections have been made for both species. Relationships between these morphometric characters and the total length of fish have been evaluated. The ratio between the length of alimentary canal and total length of fish in both species reflects their feeding habits. Histology of the ‘stomach’ and ‘intestine’ of these two species as shown by light microscopy has been described and …

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Effect Of Mechanical Injury And Low Temperature Storage On The Accumulation Of Glycoalkaloids In The Tubers Of 7 Varieties Of Potato (Solanum Tuberosum L.) Grown In Oman, Elsadig A. Eltayeb, Sana Salem Al-Sinani, I. A. Khan Apr 2025

Effect Of Mechanical Injury And Low Temperature Storage On The Accumulation Of Glycoalkaloids In The Tubers Of 7 Varieties Of Potato (Solanum Tuberosum L.) Grown In Oman, Elsadig A. Eltayeb, Sana Salem Al-Sinani, I. A. Khan

Sultan Qaboos University Journal For Science

Tubers from 7 potato varieties were analyzed for their rates of glycoalkaloid accumulation in response to stresses of three types of mechanical injury and low temperature storage. Mechanical injuries were found to greatly stimulate glycoalkaloid accumulation in both peel and flesh of tubers. The extent of glycoalkaloid accumulation appears to depend on variety, type of mechanical injury, and storage period. Most of the injury-stimulated glycoalkaloid accumulation occurred within 7 and 14 days after treatment. Cutting the tubers resulted in the highest content of glycoalkaloids both in flesh and peel up to levels that exceeded the upper safety limit of 200 …

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Effect Of Cold And Hot Temperature On Behavioral And Selected Physiological Measures Of Uromastyx Aegyptius (Agamidae), A.A. El-Banna, A.M. Al-Johany Apr 2025

Effect Of Cold And Hot Temperature On Behavioral And Selected Physiological Measures Of Uromastyx Aegyptius (Agamidae), A.A. El-Banna, A.M. Al-Johany

Sultan Qaboos University Journal For Science

The behavioral, physiological and biochemical response to low (2°C) and high (45°C) temperatures was studied in Uromastyx aegyptius. Twelve animals were divided into two experimental groups. A third control group was kept at 22 °C. All animals in the cooling, warming, and control groups were allowed a period of 24 hours for adjustments at 22 °C. Blood samples were collected from each animal when body temperature reached the corresponding levels. The results showed a significant (P<0.05) decrease in blood glucose and cholesterol levels during cooling (2°C). This reduction in extracellular fluid substrates reflects an increase in cellular uptake of these substrates. Warming (45°C) resulted in a significant (P< 0.05) increase in total proteins, urea, and uric acid. These later changes could be attributed to an increase in the evaporative water loss, particularly due to the increased observed panting, and the associated reduction in plasma volume. There were no significant (P>0.05) changes in T3 and T4, during cooling nor during warming. The results of this study suggest augmentation of anaerobic metabolism of the U.aegyptius …

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Efficient Synthesis Of The Plant Growth Regulator Ancymidol, Heiko Patzelt Apr 2025

Efficient Synthesis Of The Plant Growth Regulator Ancymidol, Heiko Patzelt

Sultan Qaboos University Journal For Science

The important cytochrome P450 inhibitor ancymidol is used as a plant growth retardant and has potential for various medicinal applications. However its high price sets economic limits to large-scale applications. Here a short and high-yielding synthesis is reported, providing ancymidol in substantial amounts in a cost- and time-efficient way.

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Physiological And Behavioral Adjustments Relative To Catecholamine Levels During Nesting In Olive Ridley (Lepidochelys Olivacea) And Hawksbill (Eretmochelys Imbricata) Sea Turtles In Masirah Island, Oman., A.Y.A Alkindi, I.Y. Mahmoud, Fatma Al-Siyabi Apr 2025

Physiological And Behavioral Adjustments Relative To Catecholamine Levels During Nesting In Olive Ridley (Lepidochelys Olivacea) And Hawksbill (Eretmochelys Imbricata) Sea Turtles In Masirah Island, Oman., A.Y.A Alkindi, I.Y. Mahmoud, Fatma Al-Siyabi

Sultan Qaboos University Journal For Science

Plasma adrenaline (ADR) and noradrenaline (NA) levels were measured for the first time in natural populations of hawksbill (Eretmochelys imbricata) and olive ridley (Lipedochelys olivacea) in Masirah Island, Arabian Sea; one of the few protected nesting grounds remaining in the world for these two endangered species. Plasma ADR and NA levels were assessed in individuals after they oviposited eggs and completed nesting exercises, and in individuals which were still searching for suitable nesting sites. Blood samples were taken from the cervical sinuses from two groups (oviposited and non-oviposited), which spent at least 1.5 h on the nesting grounds. The duration …

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Synchronization And Oscillator Death In Diffusively Coupled Lattice Oscillators, Adu A.M. Wasike Apr 2025

Synchronization And Oscillator Death In Diffusively Coupled Lattice Oscillators, Adu A.M. Wasike

Sultan Qaboos University Journal For Science

We consider the synchronization and cessation of oscillation of a positive even number of planar oscillators that are coupled to their nearest neighbours on one, two, and three dimensional integer lattices via a linear and symmetric diffusion-like path. Each oscillator has a unique periodic solution that is attracting. We show that for certain coupling strength there are both symmetric and antisymmetric synchronization that corresponds to symmetric and antisymmetric non-constant periodic solutions respectively. Symmetric synchronization persists for all coupling strengths while the antisymmetric case exists for only weak coupling strength and disappears to the origin after a certain coupling strength.

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Comparative Study Of Plasma Parameters In Olive Ridley (Lepidochelys Olivacea) And Hawksbill (Eretmochelys Imbricata) During Nesting, A.Y.A. Alkindi, I.Y. Mahmoud, J.L. Plude Apr 2025

Comparative Study Of Plasma Parameters In Olive Ridley (Lepidochelys Olivacea) And Hawksbill (Eretmochelys Imbricata) During Nesting, A.Y.A. Alkindi, I.Y. Mahmoud, J.L. Plude

Sultan Qaboos University Journal For Science

The aim of this study is to investigate the role of plasma level parameters during nesting activity and provide data potentially useful to future studies on the dynamics of reproductive and stress hormones in the most endangered sea turtle species in the world. Plasma parameters in the sea turtles, olive ridley (Lipodochelys oliveacea) and hawksbill (Eretmochelys imbricata) from Masirah Island, Oman, were analyzed relative to nesting stress. To date, no study has been conducted on plasma parameter levels in sea turtles during nesting. Field observations were conducted under ideal temperature conditions. At the time of sampling, there was no significant …

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Derivatized Pentadentate Macrocyclic Ligands And Their Transition Metal Complexes, Muhammad S. Khan, Nawal K. Al-Rasbi, Edwin C. Constable, Adrian R. Dale, Jack Lewis Apr 2025

Derivatized Pentadentate Macrocyclic Ligands And Their Transition Metal Complexes, Muhammad S. Khan, Nawal K. Al-Rasbi, Edwin C. Constable, Adrian R. Dale, Jack Lewis

Sultan Qaboos University Journal For Science

The reaction of the pendant hydroxyethyl group in the planar pentadentate macrocyclic ligand,1,11-bis(2’-hydroxyethyl)-4,8;12,16;17,21-trinitrilo-1,2,10,11-tetraazacyclohenicosa- 2,4,6,9,12,14,18,20-octaene (L2), derived from the condensation of 2,6-pyridinedialdehyde with 6,6’-bis(2’ hydroxyethylhydrazino) -2,2’-bipyridine (L1), has been investigated. Esterification reactions are facile, and the reaction of the hydroxyethyl-substituted macrocycle with thionyl chloride yields a chloroethyl derivative. Metal complexes of the new derivatized macrocyclic ligands L3-6having general formula ML3-6X2.nH2O (M = Mn, Fe, Co, Ni, Cu, Zn) are readily prepared.

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Periodic Solutions Of A System Of Delay Differential Equations For A Small Delay, Adu A.M. Wasike, Wandera Ogana Apr 2025

Periodic Solutions Of A System Of Delay Differential Equations For A Small Delay, Adu A.M. Wasike, Wandera Ogana

Sultan Qaboos University Journal For Science

We prove the existence of an asymptotically stable periodic solution of a system of delay differential equations with a small time delay t > 0. To achieve this, we transform the system of equations into a system of perturbed ordinary differential equations and then use perturbation results to show the existence of an asymptotically stable periodic solution. This approach is contingent on the fact that the system of equations with t = 0 has a stable limit cycle. We also provide a comparative study of the solutions of the original system and the perturbed system. This comparison lays the ground for …

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Biological Effects Of Em Radiations From Mobile Phones, Adel A. Ali, Ahmed M. Al-Naamany Apr 2025

Biological Effects Of Em Radiations From Mobile Phones, Adel A. Ali, Ahmed M. Al-Naamany

Sultan Qaboos University Journal For Science

Direct health effects could result following exposure to RF by thermal (heating effects). Recent Studies have shown that there are public fears on effects that can be caused mainly by holding mobile phones close to the body, or as a result of possible non-thermal effects from both phones and base stations. This paper offers an overview on the biological effects of electromagnetic radiation caused by mobile phones. Exposures of individuals to RF radiation from these sources will depend upon their proximity and may be above those from mobile phone base stations, although still well below guidelines. From a review of …

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Simulation Of M-Sequence’S Properties Through Matlab-Simulink, A. Ahmad, M. J. Al-Mushrafi, S. Al-Busaidi Apr 2025

Simulation Of M-Sequence’S Properties Through Matlab-Simulink, A. Ahmad, M. J. Al-Mushrafi, S. Al-Busaidi

Sultan Qaboos University Journal For Science

Based on an analytical study of the theory of m-sequences, a tool is developed to facilitate practicing engineers to either generate m-sequence for its application, or to test applied m-sequence, or both. The developed test–kit simulates all the properties of m-sequences including number of 1s and 0s, the run lengths, pulse periods as well as autocorrelation properties. This simplified tool is developed using MATLAB–SIMULINK with required codes as well as desired blocks. The model is cost-effective and the output files of the generated SIMULINK models can be utilized in any software program or simulation procedures.

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Effect Of Ph On The Removal Of Chromium (Cr) (Vi) By Sugar Cane Bagasse, Nasim Ahmed Khan, Syed Iqbal Ali, Sohail Ayub Apr 2025

Effect Of Ph On The Removal Of Chromium (Cr) (Vi) By Sugar Cane Bagasse, Nasim Ahmed Khan, Syed Iqbal Ali, Sohail Ayub

Sultan Qaboos University Journal For Science

The industrial estates in India are dominated by small and medium scale industries, which are posing a serious threat to the environment by virtue of discharging effluents of a polluting nature. The problems become severe due to the presence of heavy metals in the effluents. Chromium is widely used in a number of industries such as electroplating, metal finishing, cooling towers, dyes, paints, anodising and leather tanning industries. The toxicity of chromium (VI) is well known and is considered a hazard to the health of humans and animals. The presence of chromium (VI) in aquatic environments at high concentrations is …

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Tailings From Mining Activities, Impact On Groundwater, And Remediation, Khalid Al-Rawahy Apr 2025

Tailings From Mining Activities, Impact On Groundwater, And Remediation, Khalid Al-Rawahy

Sultan Qaboos University Journal For Science

Effluent wastes from mining operations and beneficiation processes are comprized mostly of the following pollutants: total suspended solids (TTS), alkalinity or acidity (pH), settleable solids, iron in ferrous mining, and dissolved metals in nonferrous mining. Suspended solids consist of small particles of solid pollutants that resist separation by conventional means. A number of dissolved metals are considered toxic pollutants. The major metal pollutants present in ore mining and beneficiation waste waters include arsenic, cadmium, copper, lead, mercury, nickel, and zinc. Tailings ponds are used for both the disposal of solid waste and the treatment of waste-water streams. The supernatant decanted …

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Use Of Isotope And Solute Chemistry To Define The Sources Of Pollution In Mawqaq Groundwater, Hail, Saudi Arabia, Ibrahim Abdulaziz Al-Sagaby, Mohamed Ali Moallim Apr 2025

Use Of Isotope And Solute Chemistry To Define The Sources Of Pollution In Mawqaq Groundwater, Hail, Saudi Arabia, Ibrahim Abdulaziz Al-Sagaby, Mohamed Ali Moallim

Sultan Qaboos University Journal For Science

Groundwater in the area is used for different purposes like domestic, agricultural, industrial and landscaping. More than sixty groundwater samples were collected in an alluvial shallow aquifer in and around Mawqaq Town. The objective was to study groundwater quality and identify the sources of Nitrate (NO3) and bacteriological pollution in groundwater using environmental isotopes (2H, 3H and 18O). The results of the study have revealed the presence of average salinity concentration higher than the permissible limits (500 mg/l) for drinking water. Three groups of water saline boundaries were identified. The presence of high nitrate as nitrogen (NO3-N) was also encountered …

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Problems Of Bacteriological Pollution In Water Wells In Wadi Hadramout Water Project, Salem M. Bin Qadhi, Saeed Y. Bashir, Taha O. Assaggaf Apr 2025

Problems Of Bacteriological Pollution In Water Wells In Wadi Hadramout Water Project, Salem M. Bin Qadhi, Saeed Y. Bashir, Taha O. Assaggaf

Sultan Qaboos University Journal For Science

This paper presents an existing problem of drinking water pollution for a small project and one of the model projects of drinking water in Yemen, designed to save and preserve good quality water for the present and future generations in the area. The paper gives the details of the project and explains the problem of bacteriological pollution and the steps undertaken to solve the problem. Some of the results for short-term solutions and recommendation for the long-term solutions are also given.

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Variation In Seedling Characteristics Of Five Populations Of Acacia Tortilis From The United Arab Emirates In Response To Increasing Sodium Chloride Concentrations, Fatma. M. Al-Ansari, Rashied. S. Modawi Apr 2025

Variation In Seedling Characteristics Of Five Populations Of Acacia Tortilis From The United Arab Emirates In Response To Increasing Sodium Chloride Concentrations, Fatma. M. Al-Ansari, Rashied. S. Modawi

Sultan Qaboos University Journal For Science

Seeds of Acacia tortilis collected from 5 sites around the city of Al Ain in the United Arab Emirates were germinated in 4 concentrations of sodium chloride (0, 20, 90 and 150 mM of NaCl). Percent of germination, rate of germination, seedling moisture content, root and shoot lengths and seedling lengths were all significantly affected by salt stress. Seeds collected from the different sites were significantly different in their response to salinity conditions. Variations in the response of seedlings from different sites to the different salt treatments suggest an underlying genetic variability within the A. tortilis populations, possibly resulting from …

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Desert Nitrogen Cycles: Fecal Nitrogen From A Population Of The Sahelian Tree Locust In Oman, Michael D. Robinson Apr 2025

Desert Nitrogen Cycles: Fecal Nitrogen From A Population Of The Sahelian Tree Locust In Oman, Michael D. Robinson

Sultan Qaboos University Journal For Science

This research quantifies the amount of nitrogen deposited by the tree locust, Anacridium melanorhodon, during an irregular population outbreak in an Acacia tortilis woodland in Oman. The average standing crop of feces was 65.28g m-2. The mean fecal crude protein and nitrogen were respectively, 20.14 and 3.22 g/100 gash-free dry weight. A hectare of this woodland would contain approximately 1.1 kg of fecal nitrogen beneath the trees. This single contribution by the locusts equals about one-third of the total standing crop of detrital nitrogen under perennial vegetation in a hectare of the Mohave Desert of North America. This, and the …

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Plasma Analysis In Normal Green Sea Turtles, Chelonia Mydas, During Two Different Periods Of Nesting At Ras Al- Hadd, Sultanate Of Oman, Abdulaziz.Y.A. Alkindi, Ibrahim.Y. Mahmoud, Humaid Khan Apr 2025

Plasma Analysis In Normal Green Sea Turtles, Chelonia Mydas, During Two Different Periods Of Nesting At Ras Al- Hadd, Sultanate Of Oman, Abdulaziz.Y.A. Alkindi, Ibrahim.Y. Mahmoud, Humaid Khan

Sultan Qaboos University Journal For Science

Plasma composition which includes total protein, cholesterol, lactate, glucose, uric acid, urea, CO2, and electrolytes (Ca++, K+, Na+, Mg++, PO4-3, Cl-), and plasma osmolarity were analyzed in normal adult nesting green turtles Chelonia mydas. Blood samples were collected in June-October at the peak of the nesting season and in November-May during the non-peak period. Plasma electrolytes values, except for PO4-3 and Cl- were significant between the two periods. Values for total proteins and uric acid were significantly different during the two periods but urea values were insignificant. Osmolarity was unchanged during the two periods. During nesting the sea turtles undergo …

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Determination Of Sugar And Mineral Contents In Some Omani Fruits, Salma M. Z.Al-Kindy, Abdulrahman O. Abdulnour, Maryam M. Al-Rasbi Apr 2025

Determination Of Sugar And Mineral Contents In Some Omani Fruits, Salma M. Z.Al-Kindy, Abdulrahman O. Abdulnour, Maryam M. Al-Rasbi

Sultan Qaboos University Journal For Science

Omani fruits were analyzed for their reducing sugar, total sugar contents and some minerals. Among the minerals studied were Ca, Mg, Na, K and P. The amounts of total sugar and reducing sugar were within the range of values reported in the literature for the analysis of fruits conducted elsewhere. The amounts of the minerals differ from the reported literature values. This may be attributed to soil composition, climate and type of cultivar.

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Measurements Of Rf Radiation In The Vicinity Of Fm And Tv Broadcasting Stations, Abdulaziz S. Al-Ruwais Apr 2025

Measurements Of Rf Radiation In The Vicinity Of Fm And Tv Broadcasting Stations, Abdulaziz S. Al-Ruwais

Sultan Qaboos University Journal For Science

This paper provides measurements of power density around an FM and VHF-TV broadcasting station and its variation with distance. The maximum measured value was about 2.4 mW/cm2 at a height of 2 meters above ground level while the average value was fluctuating around 1 mW/cm2. It was found that the measured power density increases with height above ground and it reaches about 3.5 mW/cm2 at a height of about 15 meters at a location of about 400 meters from the station. At a nearer distance of 185 meters from the tower another measurement was taken at a height of 18 …

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Endocrine, Physiological And Histopathological Responses Of Fish And Their Larvae To Stress With Emphasis On Exposure To Crude Oil And Various Petroleum Hydrocarbons, A. Y. A. Al-Kindi, J.A. Brown, C.P. Waring Apr 2025

Endocrine, Physiological And Histopathological Responses Of Fish And Their Larvae To Stress With Emphasis On Exposure To Crude Oil And Various Petroleum Hydrocarbons, A. Y. A. Al-Kindi, J.A. Brown, C.P. Waring

Sultan Qaboos University Journal For Science

Various endocrine and physiological responses of fish exposed to forceful physical and chemical stimuli are reviewed with emphasis on the effects of crude oils and their hydrocarbon constituents. The chemistry and toxicity of petroleum hydrocarbons are examined and methods for experimental exposure of fish to crude oil and petroleum hydrocarbons are considered. A variety of blood-borne parameters recognized as reliable tools in determining the relative severity of stress in fish are reviewed. The effects of stress and petroleum hydrocarbons on endocrine responses including changes in plasma catecholamines, corticosteroids, and thyroid hormones are reviewed. The physiological responses: changes in plasma glucose, …

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Dirhodium(Ii) Carbenes : The Chiral Product Cascade, Gregory H. P. Roos, Conrad E. Raab, Said Al-Hatmi Apr 2025

Dirhodium(Ii) Carbenes : The Chiral Product Cascade, Gregory H. P. Roos, Conrad E. Raab, Said Al-Hatmi

Sultan Qaboos University Journal For Science

The last decade has witnessed enormous growth in the spectrum of highly efficient asymmetric synthetic transformations. One prominent example of this progress is the application of dirhodium (II) carbenes generated from diazo- precursors. Innovative construction of ‘designer’ catalysts has played a integral role in extending the breadth of the synthetic cascade of non-racemic products now available through the range of cyclopropanation, C-X insertion, aromatic cycloaddition-rearrangement, and ylide-based reaction types. This review deals briefly with an overview of the important catalytic systems and maintains as its primary focus the cascade of diverse optically enriched products that flow from their applications.

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Research Trends : Natural Products As Pest, Microbial Disease An Tumour Control Agents, M.O. Fatope, Salma M. Z. Al-Kindi, Abdulrahman O. Abdulnour Apr 2025

Research Trends : Natural Products As Pest, Microbial Disease An Tumour Control Agents, M.O. Fatope, Salma M. Z. Al-Kindi, Abdulrahman O. Abdulnour

Sultan Qaboos University Journal For Science

The zeal to conquer human, agronomic, and veterinary diseases or pests has always sustained research interests directed at finding new medications from under explored biodiversity. The adoption of bioassay methods, which correlate with prevention, inhibition and reversal of diseases or elimination of pests, in screening natural products for bioactive compounds is critical to the discovery of new medications. This article focuses on areas of natural products chemistry that connect academia with industry. It discusses the technical skills needed to find bioactive compounds from microbes, marine invertebrates, plants and insects, highlighting the mode of action of selected bioactive compounds and bioassay …

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Ultrastructural Changes In The Epithelium Of The Stomach Of Aphanius Dispar (Cyprinodontidae), Due To Stress From Starvation, Taher A. Ba-Omar, Reginald Victor Apr 2025

Ultrastructural Changes In The Epithelium Of The Stomach Of Aphanius Dispar (Cyprinodontidae), Due To Stress From Starvation, Taher A. Ba-Omar, Reginald Victor

Sultan Qaboos University Journal For Science

Ultrastructural changes in the epithelium of the stomach of Aphanius dispar, a cyprinodont fish, due to starvation have been described. The changes in the epithelium after 24, 48, 72, 96, and 120 hours have been discussed. The degeneration of the epithelial cells commenced after 24 hours and steadily progressed till 96 hours at which the maximum change was observed. Changes in response to starvation include the disappearance of lipid droplets, mitochondrial damage, goblet cells degeneration, morphological aberration of the nuclei and overall abnormalities in the structural integrity of the rugae. This study confirms that stress due to starvation causes significant …

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Homochiral Acyl Isocyanates As Diagnostic Nmr Probes For The Enantiomeric Purity Of Chiral Alcohols, Gregory H. P. Roos, Anthony R. Donovanb Apr 2025

Homochiral Acyl Isocyanates As Diagnostic Nmr Probes For The Enantiomeric Purity Of Chiral Alcohols, Gregory H. P. Roos, Anthony R. Donovanb

Sultan Qaboos University Journal For Science

The first reported acyl and sulfonylisocyanates were developed and tested in reactions with chiral alcohols to afford diastereomeric carbamates. NMR analysis of these investigates the chemical shift discrimination that would allow these activated isocyanates to be used as diagnostic probes of enantiomeric purity.

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