School of Science and Computing (BC)http://repository.seku.ac.ke/xmlui/handle/123456789/1212024-03-28T10:13:25Z2024-03-28T10:13:25ZMechanisms of transmission of the Banana streak virus by Paracoccus burneraeMuturi, Samuel M.Wachira, Francis N.Karanja, Laura S.Njeru, Lucyline K.http://repository.seku.ac.ke/xmlui/handle/123456789/73112023-12-01T06:50:39Z2024-01-01T00:00:00ZMechanisms of transmission of the Banana streak virus by Paracoccus burnerae
Muturi, Samuel M.; Wachira, Francis N.; Karanja, Laura S.; Njeru, Lucyline K.
Like most viruses that cause plant diseases, the Banana streak virus (BSV) is dependent on several abiotic and biotic factors for its successful transmission and survival. Several BSV isolates are vectored by several mealybug species, including the oleander mealybug, Paracoccus burnerae (P. burnerae). However, the transmission mechanisms of this virus by the vector are poorly understood, yet the mechanisms are critical elements in the transmission of viruses by their putative vectors. This chapter presents a factorial experimental design results of studies conducted on three critical biotic factors that determine the successful transmission of the virus. The studies employed highly sensitive techniques such as immuno-capture polymerase chain reaction and rolling circle amplification to detect the BSV in the vector gut. The findings suggest that the virus is transmitted semipersistently by the P. burnerae vector through a noncirculative mode. These findings provide a new frontier for the development of novel control strategies for banana streak disease.
DOI: https://doi.org/10.1016/B978-0-323-90899-3.00021-5
2024-01-01T00:00:00ZInteraction force convex reduction for smooth gait transitions on human-power augmentation lower exoskeletonsAhmed, Abusabah I. A.Cheng, HongLiu, HuapingLin, XichuanJuma, Mary A.http://repository.seku.ac.ke/xmlui/handle/123456789/66792023-11-30T09:50:29Z2017-07-01T00:00:00ZInteraction force convex reduction for smooth gait transitions on human-power augmentation lower exoskeletons
Ahmed, Abusabah I. A.; Cheng, Hong; Liu, Huaping; Lin, Xichuan; Juma, Mary A.
Online gait control in human-powered exoskeleton systems is still rich research field and represents a step towards fully autonomous, safe and intelligent navigation. Many Control method performs well and with accepted interaction force between pilot and exoskeleton during system’s navigation on level walking, but with large convex when walking speed changed. Adaptive LOcally WEighted Scatterplot Smoothing (ALOESS) is a modification for LOESS regression method that combine multiple regression models for predefined convex threshold. We proposed convex reduction technique for smooth tracking of arbitrary reference trajectories. The large convex resulted during changing gait from flat terrain to stair ascent are studied in this work and the overshoots are reduced to minimize trajectory tracking error. We choose the overshoots to be reduced in this step because the they are larger than undershoots. We demonstrate the proposed control strategy on computer simulations, results show that the proposed strategy can minimize the overshoot by 46%.
DOI: https://doi.org/10.1007/978-981-10-5230-9_39
2017-07-01T00:00:00ZIn vivo anticandida activity of three traditionally used medicinal plants in East AfricaKisangau, Daniel P.Hosea, K. M.Lyaruu, H. V. M.Josep, C. C.Mbwambo, Z. H.Masimba, P. J.http://repository.seku.ac.ke/xmlui/handle/123456789/35662023-11-30T09:47:23Z2017-09-01T00:00:00ZIn vivo anticandida activity of three traditionally used medicinal plants in East Africa
Kisangau, Daniel P.; Hosea, K. M.; Lyaruu, H. V. M.; Josep, C. C.; Mbwambo, Z. H.; Masimba, P. J.
Crude extracts of Dracaena steudneri bark (DSB), Sapium ellipticum bark (SEB) and Capparis erythrocarpos root (CER) were investigated for their antifungal activity in immunocompromised mice infected with Candida albicans in an in vivo mice infection model. Extracts of these plant species are commonly used to treat fungal infections in East African countries. Three groups of white albino mice were immunosuppressed with 200 mg/kg body weight of cyclophosmamide for four consecutive days after which they were administered with 0.3 ml of 0.5 McFarland standard inoculum of C. albicans. The groups were treated with escalating doses of 100, 200 and 400 mg/kg of body weight of dichloromethane extracts. There was substantial dose dependency in all treatments given, with mice survival to the end of the experiment correlating well to the dose levels. At a dose of 400 mg/kg, C. erythrocarpos was the most effective with mice survival of 60% and organ burden clearance ranging from 64.0%–99.9% (P < 0.0001) in all treatments. The results revealed that C. erythrocarpos possessed significant potential for development into antifungal drugs suitable for control of Candida infections. The effectiveness of the plant extracts in vivo was a confirmation of the value of ethnopharmacological leads in drug discovery.
DOI: https://doi.org/10.1007/978-94-024-1120-1_14
2017-09-01T00:00:00ZCultivar Type and Antioxidant Potency of TeaWachira, Francis N.Karori, S.Kerio, L. C.Wanyoko, J. K.http://repository.seku.ac.ke/xmlui/handle/123456789/30812023-11-30T09:44:37Z2013-01-01T00:00:00ZCultivar Type and Antioxidant Potency of Tea
Wachira, Francis N.; Karori, S.; Kerio, L. C.; Wanyoko, J. K.
Many phenolics in foods and beverages are reported to have antioxidant capacities that are much higher than those of vitamin C and E, and even those of currently available synthetic antioxidants such as butylated hydroxyl toluene. In addition, phenolics in foods have other advantages over the other antioxidants, since they are water-soluble and are therefore excreted by the body; unlike the fat-based vitamin E, which is absorbed and retained even at potentially harmful levels. Tea is rich in polyphenols and its potential health benefits have largely been ascribed to the antioxidant activity of this group of molecules. The antioxidant potency of tea will, however, vary with type of tea product, cultivar type from which it is derived and even region where the tea was grown. Though green tea generally has the highest levels of catechins, total polyphenols and total antioxidant capacity, black teas processed from suitable cultivars could be as potent in antioxidant activity as the former. White tea (silvery tip), a rare specialty type of tea, is not significantly different from green tea in its composition and antioxidant capacity.
http://dx.doi.org/10.1016/B978-0-12-384937-3.00008-2
2013-01-01T00:00:00Z