Department of Physical Sciences

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    Adsorption evaluation of selected heavy metal ions by aminofunctionalized low-cost adsorbents. A Review
    (Global Scientific, 2021-07) T, Nyahanga; N, Ndung’u Samuel; N, Wanjau Ruth; W, Nthiga Esther
    Presence of heavy metals in drinking water has significant adverse effects on human wellbeing due to their toxicity nature. Several techniques have been employed to reduce their concentration to permissible levels. In recent years, adsorption has been widely investigated from low-cost adsorbents due to their cost effectiveness and easy in design. The application of amino-functionalized adsorbents for decontamination of wastewater have been reported. Generally, chemical modification of adsorbents has proved to have a higher adsorption capacity. Numerous amino- compounds such as ethylenediamine, 3-aminopropyl triethoxysilane, Triethylenetetramine, Sodium paminobenzoate, Acrylonitrile, Diethylenetriaminepentaacetic dianhydride, Polyaniline, Nitrilotriacetic acid, 3aminopyrazole, N,N - dimethyl benzal aniline, Di (2-picolyl) amine, Ethylenediaminetetraacetic acid etc. grafted on adsorbents in studying equilibrium, kinetic and thermodynamics has been reported. These adsorbents are applied extensively in the removal of heavy metal ions such as Cu2+, Cd2+, Pb2+, Ni2+, Cr3+, Co2+, As5+ among others. The paper reviews the applicability of vast amino-functionalized adsorbents in the study of equilibrium, kinetics and thermodynamic adsorption studies of heavy metal ions from aqueous solutions
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    A Gold Nanoparticle-Based Colorimetric Probe for Detection of Gibberellic Acid Exuded by Ralstonia solanacearum Pathogen in Tomato (Solanum lycopersicum L.)
    (International Journal of Horticultural Science and Technology, 2021-01-27) Aoko, Ivy Lynn; Ondigo, Dezzline; Kavoo, Agnes Mumo; Wainaina, Cornelius; Kiirika, Leonard
    We report a simple colorimetric probe based on gold nanoparticles (AuNPs) for detecting Ralstonia solanacearum. The AuNPs were synthesized through reduction with citrate ion and characterized by ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The freshly synthesized AuNPs were brick red due to an intense surface plasmon absorption band at 520 nm. Upon interaction with synthetic gibberellic acid (GA3), a bathochromic shift occurred in the surface plasmon resonance (SPR) peak of AuNPs to higher wavelengths. The 'eye-ball' limit of detection was 0.2 ppm. This shift was accompanied by a change in the color of the AuNPs from brick red to purple. Soil samples were collected from the rhizosphere of tomato plants, exhibiting bacterial wilt symptoms and pure cultures of Ralstonia solanacearum isolated using a modified Kelman’s TZC medium. Gibberellins (GA) were extracted from the culture of R. solanacearum using ethyl acetate and characterized using fourier transform infrared spectroscopy (FT-IR). AuNP solution aggregation was induced by GA-mediated R. solanacearum. A color change from brick red to purple was also observed. The results illustrated the use of both SPR wavelength-shift sensing and visual color change to detect molecules of biological relevance
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    To Investigate the Effect of Microwaves Irradiated Water and Feeds On The Broilers.
    (UGC Care listed, 2020-02) Kihiko, J. M.; Azhar, Shaikh Mohd.; Makena, Linet; Rabbani, Gulam
    In electromagnetic spectrum, microwaves radiation spans a range from 300 MHz to 300 GHz. These radiationshave been used in many devices that are used by humanbeings.They may be very harmful for living organisms. Bad effects of microwaves have also been investigated for several crops. This work investigates the effect of microwaves treated water and microwaves warmedfeeds to thebroiler chicken. 1100 Watt and 2450MHz power microwaveoven was used to irradiate chicken’s drinking water and feeds.During investigations, many parameterssuch as temperature, humidity, quality of water and food were well maintained.In conclusion, measuring body weight may be a useful tool to estimate growth potential rather than using body height and length. The broilerused microwavedradiated water and feeds shows better growth rate as compared to others that used normal water and feeds and that used boiled water and warmed feeds.
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    Hydromagnetic Turbulent Flow Between Two Parallel Infinite Plates
    (Science Journal of Applied Mathematics and Statistics, 2017) Karimi, Kennedy John Mwangi; Kinyua, Dickson Kande
    In this study we shall investigate hydromagnetic turbulent unsteady flow of an incompressible electrically conducting fluid between two parallel infinite plates. The flow variables such as velocity and thermodynamic properties at every point of fluid vary with respect to time. The effect of an applied transverse magnetic field normal to the main flow direction on the dynamic behavior of the fluid when the lower plate is stationary and the upper plate is impulsively started in opposite direction at constant velocity shall be investigated. Further, we shall investigate how the various parameters such as Peclet Number and Eckert Number affect the flow; in particular, velocity and temperature profiles. A finite difference method shall be used to solve the coupled non-liner and dimensionless partial differential equations governing this problem
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    Anti-Pyretic Properties of Methanolic Bark Extracts of Terminalia brownii in Wistar Rats ( Rattus novegicus )
    (J Pharmacogn Nat Prod, an open access journal, 2016) Mbinda, Wilton; Kasili, Sichangi; Mbiri, Jane W; Kisangau, Patrick D; Piero, Ngugi M
    The conventional drugs used to manage fever are usually not affordable, not easily available and have adverse side effects. Alternative therapeutic agents, like medicinal plant derivatives, should therefore be developed because they have been reported to be more affordable, more readily available and have lesser side effects. Terminalia brownii is traditionally used to manage fever but this ethno-medicinal claim lacks scientific validation. The present study therefore evaluated the anti-pyretic activity of T. brownii in Wistar rats. Fresh bark samples of T. brownii were collected from Kitui County, Kenya. This study used 30 adult male Wister rats that were 2-3 months old and weighing 140-180 g was used for the experiments. Steam-distilled turpentine was the pyrogen used to induce pyrexia and Aspirin was used as the reference drug. The extract reduced the elevated rectal temperatures by between 1.154.38% while aspirin reduced the elevated rectal temperatures by between 0.00-4.85%. The present study showed a significant dose-dependent anti-pyretic activity of methanolic bark extracts of T. brownii hence validating its folklore use as a fever remedy.
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    Anti-Pyretic Properties of Methanolic Bark Extracts of Terminalia brownii in Wistar Rats (Rattus novegicus)
    (Journal of oJ Pharmacognosy & Natural Products, 2016) Mbinda, Wilton; Kasili, Sichangi; Mbiri, Jane W; Kisangau, Patrick D; Piero, Ngugi M
    The conventional drugs used to manage fever are usually not affordable, not easily available and have adverse side effects. Alternative therapeutic agents, like medicinal plant derivatives, should therefore be developed because they have been reported to be more affordable, more readily available and have lesser side effects. Terminalia brownii is traditionally used to manage fever but this ethno-medicinal claim lacks scientific validation. The present study therefore evaluated the anti-pyretic activity of T. brownii in Wistar rats. Fresh bark samples of T. brownii were collected from Kitui County, Kenya. This study used 30 adult male Wister rats that were 2-3 months old and weighing 140-180 g was used for the experiments. Steam-distilled turpentine was the pyrogen used to induce pyrexia and Aspirin was used as the reference drug. The extract reduced the elevated rectal temperatures by between 1.15- 4.38% while aspirin reduced the elevated rectal temperatures by between 0.00-4.85%. The present study showed a significant dose-dependent anti-pyretic activity of methanolic bark extracts of T. brownii hence validating its folklore use as a fever remedy.
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    Water Resources and Management under Increasing Urban Demography: A Kenyan Perspective—A Review
    (Journal of Water Resource and Protection, 2018) Ondigo, Deziline Adhiambo; Kebwaro, Jeremiah; Kavoo, Agnes Mumo
    The United Nations classifies Kenya as a water-scarce country since it has less than 1000 m3 per capita of renewable freshwater supplies. Numerous factors including global warming, contamination of drinking water, and a lack of investment in water resources have aggravated the water crisis in Kenya. Estimates indicate that only about 56% of its population has access to safe water supply. Like many developing countries, Kenya recognizes the crucial role of water in realizing its development goals. Its economic performance and poverty reduction are critically dependent on clean water availability for agriculture, industrialization, energy production and tourism among others. Similar to most developing countries, Kenya suffers from lack of human, monetary and institutional capabilities to efficiently provide clean and sufficient water to its citizens. The water shortage in the major cities is acute and chronic and has continued to worsen with increasing urbanization, water pollution and encroachment of water catchment areas by humans and invasive plant species. Despite the water challenges facing the urban populations, Kenya possesses sufficient water resources to meet demand if the available resources are properly managed. Several initiatives are being put in place in Kenya to mitigate the water challenges and protect water resources in Kenya. These include enacting of water policies to protect water catchment areas, reduce pollution and enhance access to clean water.
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    Analysis of the Impact of Cross-sectional Data Discrepancies on the Effectiveness of Radiation Shielding Design Using Monte Carlo Codes
    (International Journal of Physics, 2019) Kebwaro, Jeremiah Monari
    The effect of cross-sectional data discrepancies on the effectiveness of radiation shielding design has been investigated in this paper. The MCNP code with cross-sections from ENDF/B-V and ENDF/B-VII has been used to determine the gamma ray dose equivalent, H*(10), behind a lead glass shield enclosing a slow neutron source. It is observed that the radiative capture gamma ray dose behind the shield is higher when ENDF/B-V cross-sections are used compared to that produced by ENDF/B-VII cross-sections. The discrepancy is due to absence of energetic primary gamma rays when ENDF/B-VII is used. The results show that shielding design using ENDF/B-VII cross-sections could underestimate the shield by a fair margin and compromise safety. It is therefore necessary to consider more than one release of ENDF/B when using lead glass for shielding slow neutron capture gamma rays. The discrepancies need to be addressed in the next releases.
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    Evaluation of In vivo Toxicity of Methanolic Leaf Extract of Vernonia lasiopus (O. Hoffman)
    (Journal of Pharmacognosy & Natural Products, 2017) Mbinda, Wilton M; Ngugi, Mathew P; Koech, Samson C; Muthoni, Beatrice G; Musila, Michael N
    The main objective of this study was to evaluate the in vivo toxicity of methanolic leaf extract of Vernonia lasiopus. To provide information on the safety of V. lasiopus, we evaluated its acute and sub-chronic toxicity in Wistar rats. For evaluation of acute toxicity of the plant extract, five Wistar rats were orally dosed with 2000 mg/kg body weight sequentially. Sub-chronic toxicity was tested in twenty Wistar rats using three extract doses 100, 300 and 1000 mg/kg body weight. They were orally administered for 28 days. Mortality and toxicity signs were monitored during the study period. At the end of the experiment, the animals were sacrificed, their internal organs weighed and blood samples collected for haematology and biochemical analysis. In acute toxicity, no single death was reported; leading to conclusion that the median lethal dose (LD50) of methanolic leaf extract of V. lasiopus is beyond 2000 mg/kg body weight. In sub-chronic toxicity studies, V. lasiopus lowered total proteins in all the study groups significantly. Albumin was also lowered at extract dose of 1000 mg/kg body weight. In addition, it resulted to significant neutropenia, lymphocytosis and thrombocytosis in the group administered with dose extract of 1000 mg/kg body weight (P˂0.05). It was therefore concluded that methanolic leaf extract of V. lasiopus is safe for use when administered at therapeutic doses. The plant extract may also be useful in the management of haematological disorders especially thrombocytopenia.
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