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In this research work, the extraction, characterization, device fabrication, and theoretical investigation of Hibiscus sabdariffa plant extract, for possible application in solid DSSCs, are reported. The plant extract was analyzed using FT-IR and UV–Vis spectrophotometry. Polyaniline on graphene was used as the counter electrode whereas titanium (IV) oxide was used as the photo anode for the fabricated DSSCs. The experimental results obtained for the open circuit voltage, short circuit current density, field factor, maximum power and conversion efficiency are 0.925 V, 0.073 A/cm2, 1.43, 1.04 W, and 0.044 % respectively. The excited states of anthocyanin (delphinidin) and quercetin, the most stable structures of Hibiscus sabdariffa plant extract, were studied using density functional theory method. In addition, the theoretical open circuit voltage, light harvesting efficiency, coupling constant, free energy change, and HOMO–LUMO energy gap were predicted for the photovoltaic properties. The theoretical results suggest that quercetin has relatively better photovoltaic properties and, hence, potentially a better dye for solar cell application.

This paper describes a study on the oestrous and ovarian activity and responses to prostaglandin F2 alpha (PGF2 alpha) administration and artificial insemination in zebu heifers. Four cycling heifers were artificially infected with 5 x 10(6) Trypanosoma vivax organisms. Two heifers served as controls. Two injections of PGF2 alpha were given 11 days apart, commencing at the peak of parasitaemia in the infected animals, followed by artificial insemination 72 and 96 h after the second administration of PGF2 alpha. Sera were analysed for progesterone by radioimmunoassay, while ovarian activity and oestrus were determined by rectal palpation and visual observation, respectively. All the infected heifers developed the clinical disease. All control and infected heifers had progesterone profiles consistent with luteolysis and the occurrence of oestrus following the second administration of PGF2 alpha. Progesterone levels did not return to normal luteal values in infected animals, however, whilst they did so in control animals. No control or infected heifers became pregnant. The findings suggest that PGF2 alpha will induce a non-fertile oestrus in zebu heifers acutely infected with T. vivax. Re-ovulation is also inhibited within 22 days in a majority of infected animals.

The development and survival of the eggs of Haemonchus contortus on pasture at Ibadan were studied by spreading faeces containing eggs on grass plots from October 1973 to October 1974. Development of the eggs to the infective larvae took place within one week in May, June, July, September and October. Larvae were not recovered in the other months. Their survival times were 28, 42, 42, 35, 63 and 49 days respectively in October 1973. May, June, July, September and October 1974. Rainfall was the most important epizootiological factor which influenced the development and survival of the infective larvae. Development of the eggs to the infective larvae took place when the mean daily rainfall for the first 7 days was 3 mm or more. The survival time of the larvae appeared to be prolonged when rain fell evenly throughout the periods the larvae were on pasture.

During the dry season (January to March) in Calabar, strongyloid eggs in cattle faeces hatched within 24 h and developed to infective larvae within 7 days on pasture. The larvae survived 6 weeks in January, 4 weeks in February, 8 weeks in March and 10 weeks in April. Rainfall rather than temperature played the major role in the development and survival of the larvae on pasture during this period. There results show that the hatching of the eggs and the development of the larvae can take place at any time of the year in Calabar.