Time filter

Source Type

Wambu E.W.,Kenyatta University | Wambu E.W.,Bondo University College | Onindo C.O.,Kenyatta University | Ambusso W.,Kenyatta University
Clean - Soil, Air, Water | Year: 2013

The problem of high fluoride in water sources in Africa and the rest of the developing world has exacerbated in the latest past due to increasing shortage of water. More people are being exposed to high water fluoride resulting in elevated levels of fluorosis in the societies. Fluoride (F) adsorption from solutions using a siliceous mineral from Kenya (M1) was studied on batch basis and results verified on high fluoride water using fixed-bed column experiments. About 100% batch F adsorption was achieved at 200mg/L F concentration, 0.5g/mL adsorbent dosage, 303-333K, and pH 3.4±0.2. Based on Giles classifications, F adsorption isotherm was found to be an H3 type isotherm. The equilibrium data was correlated to Freundlich and Langmuir models and the maximum Langmuir adsorption capacity was found to be 12.4mg/g. Column experiments were conducted for different fluoride concentrations, bed depths, and flow rates. The F breakthrough curves were analyzed using the Thomas model and efficient F adsorption was found to occur at low flow rates and low influent concentrations. The Thomas F adsorption capacity (11.7mg/g) was consistent with the Langmuir isotherm capacity showing that M1 could be applied as an inexpensive medium for water defluoridation. Fluoride adsorption onto a siliceous mineral of a Kenyan origin, M1, was studied in batch and fixed-bed column adsorption systems. The findings are that F could be removed most efficiently at low influent F concentration and lowest flow rates. It could be demonstrated that M1 is an alternative low-cost adsorbent to remove F from water. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Li Y.,The University of Shimane | Ogola H.J.O.,The University of Shimane | Ogola H.J.O.,Bondo University College | Sawa Y.,The University of Shimane
Applied Microbiology and Biotechnology | Year: 2012

l-Amino acid dehydrogenases are a group of enzymes that catalyze the reversible oxidative deamination of l-amino acids to their corresponding 2-oxoacids, using either nicotinamide adenine dinucleotide (NAD +) or nicotinamide adenine dinucleotide phosphate (NADP +) as cofactors. These enzymes have been studied widely because of their potential applications in the synthesis of amino acids for use in production of pharmaceutical peptides, herbicides and insecticides, in biosensors or diagnostic kits, and development of coenzyme regeneration systems for industrial processes. This article presents a review of the currently available data about the recently discovered amino acid dehydrogenase superfamily member l-aspartate dehydrogenase (l-AspDH), their relevant catalytic properties and speculated physiological roles, and potential for biotechnological applications. The proposed classification of l-AspDH on the basis of bioinformatic information and potential role in vivo into NadB (NAD biosynthesis-related) and non-NadB type is unique. In particular, the mesophilic non-NadB type l-AspDH is a novel group of amino acid dehydrogenases with great promise as potential industrial biocatalysts owing to their relatively high catalytic properties at room temperature. Considering that only a few l-AspDH homologs have been characterized so far, identification and prodigious enzymological research of the new members will be necessary to shed light on the gray areas pertaining to these enzymes. © 2011 Springer-Verlag. Source

Ambede J.G.,Maseno University | Netondo G.W.,Maseno University | Mwai G.N.,Bondo University College | Musyimi D.M.,Maseno University
Brazilian Journal of Plant Physiology | Year: 2012

The effects of NaCl salinity on seed germination, growth, physiology, and biochemistry of two bambara groundnut landraces (Vigna subterranea (L.) Verdc), Kakamega (white seed coat) and Mumias (red seed coat), were investigated with the aim of establishing traits, which can provide a basis for breeding to salt tolerance in groundnuts. A study was conducted under laboratorial and greenhouse conditions. Bambara groundnut seeds and plants were subjected to five concentrations of NaCl solutions with several electrical conductivities: 0 (control), 6.96, 12.93, 19.89, and 25.86 dS m -1. Germination percentage, growth, chlorophyll fluorescence, and leaf chlorophyll content were determined. Sodium chloride salinity (p<0.05) significantly decreased germination and plant growth in both landraces. Mumias had significantly higher total chlorophyll, chlorophyll a and b content compared to Kakamega landrace. Salinity significantly decreased Fv/Fm ratio and electron transport rate in the two landraces, however there were no significant (p>0.05) differences in the Fv/Fm values for Mumias' landrace, as compared to the Control. Overall, Mumias' landrace seeds seemed to be more salt-tolerant at higher salinity levels compared to Kakamega. A greater reduction in growth in Mumias than in Kakamega is a possible indicator for salt tolerance. The chlorophyll fluorescence parameters may not be used to identify salt sensitivity between the two landraces. The results indicated that leaf area and seed germination were suitable parameters for screening the two bambara landraces for salt tolerance. Source

Marete A.G.,University of Nairobi | Jung'a J.O.,University of Nairobi | Mosi R.O.,Bondo University College
Livestock Research for Rural Development | Year: 2011

The level of inbreeding of the Kenya Alpine dairy goat was investigated by use of Brian Kinghorn's Pedigree viewer© software. From 1,067 doe records, data on parentage was extracted and this resulted to 3,516 individual records that were used for calculating individual inbreeding coefficients for the period 1999 to 2009. The rate of inbreeding (ΔF) was estimated as the difference between the individual inbreeding (Ft) and the inbreeding of the parents (Ft-1) divided by (1-Ft-1). The proportion of animals that was inbred increased from 0.00 (average F = 0) in 1990 to 0.38 in 2009 (average F = 0.012). Inbreeding depression on body weight was significant (P<0.05). In general the level of inbreeding in this population was very low. Further investigation on the birth weight and weaning weight was carried out. Regression analysis indicated that birth weight (p<0.05) and weaning weight (p<0.01) had improved in inbreds. The decrease in weight at first service and at first kidding was statistically insignificant. Kidding interval increased (p<0.01) due to inbreeding. Rate of decline in weight at first service and at first kidding, was different from zero (p<0.01). Effect of inbreeding on growth and reproductive traits in Kenya Alpine goats was not very pronounced in the flock. Source

Otieno Obonyo G.,Maseno University | Awuor Ayieko M.,Bondo University College | Ouma Kambona O.,Maseno University
International Journal of Hospitality and Tourism Administration | Year: 2014

This exploratory research sought to identify important food preparation factors and attributes in staging memorable experiences. Self-administered questionnaires were distributed to 166 hotel managers drawn from 62 hotels in Western Kenya. Descriptive statistics, factor and regression analysis in SPSS were used to analyze data collected. A three-factor solution: food preparation process, food preparation benefit and food preparation input resulted. Implications of these results are discussed in light of the increasing demand for distinctive experiences in the hospitality and tourism industry. © Taylor & Francis Group, LLC. Source

Discover hidden collaborations