1,006 research outputs found

    Aqueous to organic phase transfer of Au<SUB>25</SUB> clusters

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    Aqueous to organic phase transfer of water soluble sub-nanocluster, Au25SG18 (-SG, glutathione thiolate) is demonstrated using the phase transfer reagent, tetraoctylammonium bromide. The phase transfer occurred by the electrostatic attraction between the hydrophilic carboxylate anion of the glutathione ligand on the cluster surface in the aqueous phase and the hydrophobic tetraoctylammonium cation in the toluene phase. Detailed spectroscopic characterization of the phase transferred cluster using optical absorption, photoluminescence and X-ray photoelectron spectroscopy showed that the cluster retains its integrity during the phase transfer. The interaction of the cluster with the phase transfer reagent can be studied with infrared spectroscopy. The phase transferred cluster can be dried and redissolved in an organic medium, just as the original cluster. This is the first report of the phase transfer of a sub-nanocluster, keeping the cluster core intact. The effect of dilution and pH on phase transfer of this cluster is studied in detail. This method promises several possibilities to explore the properties, reactivity and applications of sub-nanoclusters both in the aqueous and organic phases

    Investigation of the Geotechnical Engineering Properties of Laterite as a Subgrade and Base Material for Road Constructions in Nigeria

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    This project is an in-depth investigation of the geotechnical engineering properties of subgrade and base soils used in the construction of Omolayo Road in Akobo Area of Lagelu local government, Oyo State, Nigeria. Subgrade samples were collected at chainages 0+000, 1+000, 2+000, 3+000 and 4+000 respectively at depths ranging 0.5m to 1.0m, while the base sample was collected from one of the heaps of laterite brought from the borrow-pit at Oluwo area along New Ife Express Road, Oyo State, Nigeria. The samples were subjected to the following laboratory tests; Particle (grain) size analysis, Atterberg limit test, Compaction test, California bearing ratio (CBR) test and Specific gravity test. The particle size analysis results showed that all samples, both subgrade and base were well graded since their Uniformity Coefficients were greater than 15. It further revealed that base sample were more plastic compared to subgrade samples since it has highest percentage of clay passing sieve no. 200 (75µm) i.e. 27.60%. This indicates that samples with high silt clay content are susceptible to volume changes when wet. The liquid limit and plastic index range from 24% to 48% and 2.7% to 25% respectively with base sample having the highest in both cases. This shows that base sample has high clay content and its load bearing capacity could be reduced when wet. The maximum dry densities ranged from 1.90mg/m3 to 2.19mg/m3 and Optimum moisture contents range from 5.4% to 14.2% respectively. The California bearing ratio is from 78% to 132% (unsoaked). The Specific gravity results ranged from 2.65 to 2.68. The samples were classified using AASHTO classification. The AASHTO system classified the subgrade samples as A-1-b and A-2-4 constituting 50% and 33.3% respectively, and base sample classified as A-2-7 constituting 16.6%. This shows the subgrade samples are excellent to good while base sample is fair to poor. Keywords: Laterite, subgrade, base, particle size analysis, atterberg limit, compaction test, California bearing ratio, Specific gravit

    Synthesis,Characterization,Thermal and Kinetic Photo Chemical Decomposition Study of New Azo Dye 7-[2-(BenzImidazolyl)Azo]-8-Hydroxy Quinoline and its Znic (II) Complex

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    This research includes preparation and spectral identification of a new azo ligand7-[2-(Benzimidazolyl) azo]-8-Hydroxy quinoline (BIAHQ) by using UV-Vis,  IR, 1H-NMR and mass spectra.The preparation of Zn(II)-complex of this ligand and identification by UV-Vis, IR radation spectrum,which characterized by elemental analysis.The analytical data shows that the metal to ligand ratio [M:L] of Zn(II)complex is 1:2.Decomposition kinetics was studied photochemical complex through irradiation solution complex single wavelength light ?=365 nm ,at temperature of 25 ?C for 60 minutes  and ethanol solvent was found to be the reaction from first order. Also,the calculated rate concetant photolysis kd mediated follow spectral changes during the process of irradiation . In order to reach the optimal conditions for the dissolution of the complex, it has been studied the impact of several factors on photochemical reaction of disintegration of the complex which include : Study the effects of the change in the intensity of light. More over  disintegration of the complex has been studied in temperature range 15-30?C, and studied the effects of the acidic function within range 3-9.The effects of several alcoholic solvents were studied on the rate of disintegration and these solvents are methanol, ethanol, isopropanol and1-butanol.Free ligand and Zn(II)complex were submitted to thermal analysis(TGA and DSC) activation thermodynamic data are calculated

    CANCER GROWTH TREATMENT USING IMMUNE LINEAR QUADRATIC REGULATOR BASED ON CROW SEARCH OPTIMIZATION ALGORITHM

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    The rapid and uncontrollable cell division that spreads to surrounding tissues medically termed as malignant neoplasm, cancer is one of the most common diseases worldwide. The need for effective cancer treatment arises due to the increase in the number of cases and the anticipation of higher levels in the coming years. Oncolytic virotherapy is a promising technique that has shown encouraging results in several cases. Mathematical models of virotherapy have been widely developed, and one such model is the interaction between tumor cells and oncolytic virus. In this paper an artificially optimized Immune- Linear Quadratic Regulator (LQR) is introduced to improve the outcome of oncolytic virotherapy. The control strategy has been evaluated in silico on number of subjects. The crow search algorithm is used to tune immune and LQR parameters. The study is conducted on two subjects, S1 and S3, with LQR and Immune-LQR. The experimental results reveal a decrease in the number of tumor cells and remain in the treatment area from day ten onwards, this indicates the robustness of treatment strategies that can achieve tumor reduction regardless of the uncertainty in the biological parameters

    The Growing Phenomenon of Street Children in Tehran

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    This study examines the increasing phenomenon of street children in Tehran. It focuses on the challenges and risks these&nbsp;children encounter and the overall implications on the general populace and the country as a whole. The study adopted&nbsp;both primary and secondary sources of data. The primary data were qualitative design (face-to-face interview). The&nbsp;population include all street children in Tehran. Purposive and snowball sampling techniques were used to select a total of&nbsp;3725 street children for this research. Information gathered was coded, categorized and analyzed using EZ Test Software&nbsp;to quantify the results and demonstrate the frequency of responses to the open-ended questions relating to the research&nbsp;interest. The study found that there are two categories of street children in Tehran (children of the street and children&nbsp;on the street), they experience several challenges such as extortion, exploitation, rape, and harassment. Furthermore,&nbsp;they engage in different activities to get money or survive. The study concludes that disrupted socioeconomic structure&nbsp;of families and the influx of different categories of people into the cities are the major causes of the phenomenon. The study, therefore, recommends that addressing the socioeconomic challenges should be the first approach toward ending&nbsp;the menace

    An FPGA Based Vehicles Density Dependent Intelligent Traffic Light System

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    In this paper, a vehicles density dependent intelligent traffic light system based on FPGA has been built. The intelligent traffic light system counts the number of available vehicles in the sides of the traffic intersection via the sensors placed on the ends of the road. Subsequently, it determines passage time required for each side, depending on the density of existing vehicles in it, in order to pass the largest number of vehicles in the intersection during a certain time. The proposed system is built using VHDL, simulated using Xilinx ISE 9.2i package, and implemented using Spartan-3A XC3S700A FPGA kit. Implementation and Simulation behavioral model results show that proposed system fits the specified functional requirements, and finds a solution to overcome the problem of traffic jam at intersections

    Haemoglobin phenotypes and the risk of asymptomatic malaria parasitemia among blood donors in northwest Nigeria: clinical implications in the practice of tropical transfusion medicine

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    Background: In malaria-endemic populations, sickle cell trait (SCT) protects against both severe and non-severe malaria, but inconsistencies exist about protective effect of SCT on asymptomatic malarial parasitemia (AMP). Surprisingly, the effect of Hb-phenotypes on AMP has not been explored among blood donors in Nigeria or other malaria-endemic countries, where risks of AMP and transfusion transmitted malaria (TTM) are high. The objective of this study is to determine risk of AMP with respect to donor Hb-phenotypes (SCT versus HbAA), and elucidate clinical implications of AMP with respect to risk of TTM vis-à-vis the practice of transfusion medicine in Nigeria, and by implication other malaria-endemic tropical countries.Methodology: Analysis of 100 blood donors with AMP (cases) and 100 donors without AMP (controls) was performed. Frequencies of SCT and HbAA (determined by Hb electrophoresis) among cases and controls were compared by X2 -test. Risks of AMP (detected by microscopy) with respect to Hb-phenotypes were expressed as Odds ratios (OR) by case-control logistic regression.Results: In comparison with blood donor without AMP (controls), donors with AMP had lower frequencies of SCT (12% vs 28%, p&lt;0.05) with corresponding higher frequencies of HbAA (88% vs 72%, p&lt;0.05). HbAA is associated with high risk of AMP (OR=2.91, 95%CI: 2.10-3.48, p=0.021), while SCT is associated low risk of AMP (OR=0.49, 95%CI: 0.27-0.73, p=0.032).Conclusion: This finding shows that donor SCT is a surreptitious mitigator of the risk of AMP and TTM in the tropics. Therefore, patients who are selectively transfused with HbAA blood (e. g. neonates and sickle cell disease patients) could be at greater risks of TTM, and such patients need closer post transfusion monitoring. The risk of TTM calls for diligent post transfusion haemovigilance in Nigeria and other malaria endemic tropical countries in Africa Keywords: blood donors, sickle cell trait, asymptomatic malaria parasitemia, transfusion transmitted malari

    Influence of Human Activities on the Water Quality of Ogun River in Nigeria

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    The quality of Ogun River in south-west, Nigeria was investigated by a field survey; covering the dry season and rainy season. Water samples were collected from seven sites (including an Abattoir, a market, residential community and a brewery); analysis of the physico-chemical parameters using standard methods and their environmental effects on the river were investigated. Generally, the value/degree of dissolved oxygen, phosphate, BOD, COD, pH, temperature, hardness from the sites during the rainy and dry seasons were compared with the World Health Organization (WHO) standards for domestic and commercial water. The traces of some hazardous physical and chemical impurities in the river were above the acceptable limits; and thereby pose a health risk to several rural communities who rely heavily on the river primarily as their source of domestic water. The study revealed a need for continuous pollution monitoring and management program of surface water in Nigeria. Keywords: surface water, water quality, water pollution, field survey, physico-chemical analysi

    The Approximation of Weighted Hölder Functions by Fourier-Jacobi Polynomials to the Singular Sturm-Liouville Operator

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    تم مناقشة دوال هولدر المرجحة التي تحقق تقارب متعددات حدود جاكوبي لمعادلة ستورم- ليوفيل المنفردة من الدرجة الثانية. هذا يتوافق مع تحويلات جاكوبي المعممة ومعايير النعومة. يهدف هذا البحث ويركز على تحسين طرق التقريب وإيجاد أفضل تقريب على هذا النوع من الفضاءات عن طريق تحسين معايير النعومة. علاوة على ذلك، يتم النظر في بعض خواص معايير النعومة والقيود العليا والسفلى لدرجة تقريب الدالة.       In this work, a weighted H lder function that approximates a Jacobi polynomial which solves the second order singular Sturm-Liouville equation is discussed. This is generally equivalent to the Jacobean translations and the moduli of smoothness. This paper aims to focus on improving methods of approximation and finding the upper and lower estimates for the degree of approximation in weighted H lder spaces by modifying the modulus of continuity and smoothness. Moreover, some properties for the moduli of smoothness with direct and inverse results are considered

    INVESTIGATION OF SOME CHEMICAL CONSTITUENTS AND ANTIOXIDANT ACTIVITY OF ASPARAGUS SPERNGERI

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    Objective: Asparagus sprengeri (A S) is an ornamental plant cultivated in EGYPT. This study was designed to investigate some lipid and flavanoid constituents, in addition to the evaluation of antioxidant activity of different extracts of the plant. Methods: Two phospholipid were identified by (HPTLC). The fatty acid methyl ester and unsaponifiable matter were analyzed by GC. Four flavonoids were isolated by CC and purified by PPc. Identification of isolated flavanoidal compounds was carried by spectroscopic analysis Viz, TLC,PC, UV, EL-MS and H-1– NMR. The different extracts were tested for their free radical scavenging activity using DPPH and β-Carotene- linoleic acid bleaching assay. Results: Four flavonoids, were isolated, apigenin, dihydroquercitin, naringenin, apigenin- 7-o- glucoside Nine fatty acids, Myrestic and linoliec acids were the major components. The unsaponifiable matter was found to be a mixture of hydrocarbons from (C13– C28) and cholesterol two classes of phospholipid were identified namely L-α-Phosphatidyl-DL-glycerol and L-α- Phosphatidylethanolamine. The alcoholic extract of the plant has moderate antioxidant activity with EC50 0.114 and 0.110 mg/ml for the DppH and β-carotene methods respectively Conclusion: Asparagus sprengeri can be used as the natural antioxidant. Flavonoids are suggested to be a group of key antioxidants in Asparagus
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