Browsing by Author "Ochieng Ombaka"

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    SENSITIVITY ANALYSIS OF TREATMENT AND COUNSELING IN A CO INFECTION MODEL OF HIV/AIDS, TUBERCULOSIS AND MALARIA
    (https://www.researchgate.net/publication/335635468, 2016-02-01) Ochieng Ombaka
    This study presents a co infection deterministic model defined by a system of ordinary differential equations for HIV/AIDS, malaria and tuberculosis. The model is analyzed to investigate the potential impact of counseling and treatment on disease progression by carrying out sensitivity analysis of the reproduction number with respect to counseling and treatment. The sensitivity indices of the reproduction numbers RH, RHM, RHT and RHMT with respect to treatment and counseling for the HIV/AIDS individuals showed that counseling is the most sensitive pa- rameter in controlling the co infections.
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    Utility Of 3-Hydroxy-3-M-Tolyl-1-P-Methoxyphenyltriazene As Chromogenic Reagent For Spectrophotometric Determination Of Nickel (II) In Environmental Samples
    (IOSR Journal of Environmental Science, Toxicology and Food Technology (IOSR-JESTFT), 2018-07-02) Ochieng Ombaka
    A selective and sensitive spectrophotometric method for Nickel (II) determination using 3-Hydroxy-3m-tolyl-1-p-methoxyphenyltriazene is described. The physical characteristic of the reagent was light yellow shinning needles with the melting point of 1120C. The elemental analysis results agreed very well with those of theoretical for C, H and N. Nickel (II) reacts with the reagent in pH range of 8.0-8.3 to give a yellow colored complex with a composition of 1:2 at a working wavelength of 412nm. The molar absorptivity coefficient, Lambert-Beer’s Law range and stability constant (Log10β) were 20800dm3 mol-1cm-1, 0.25-1.25x10-5M and 10.4091 respectively. The complex with a composition of 1:2 (Ni:L) is more stable and more sensitive in comparison with some other hydroxytriazenes previously studied for Nickel(II) determination. Many cations and anions do not interfere with Nickel (II) determination. However, Sn2+ and Cu2+ if present interfere seriously with the Nickel (II) determination. The interference of Cu2+ can be avoided by masking it with oxalate solution. The proposed method was used for determination of Nickel (II) in soil and plant samples from Meru dumpsite. The t-test and F-test values showed that there is no statistical difference in the results of flame atomic spectrophotometric and the proposed method. Hence, the method can be employed for Nickel (II) determination in the environmental samples.