Faculty of Science

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    Open Access
    Generalized Numerical Solution of Mixed Systems of Elliptic and Hyperbolic Partial Differential Equations
    (University of Lagos, 1972) Ekogbulu, Festus Oluwayimika
    Research work principally of Von Neumann; Richard Courant et. al established firmly the use of finite -difference techniques for the solution of linear partial differential equations
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    Open Access
    Some Problems in Inhomogeneous Viscous Flow
    (University of Lagos, 1974) Adeboye, Enoch Adejare
    This thesis serves a dual purpose. First, a method is presented which simplifies the integration of the governing steady stage equations of an incomprehensible viscous fluid with vanishing body and inertia forces. The method takes advantage of potential theory to reduce any fluid problem to that of differential operators acting upon harmonic functions. This is in contrast to the conventional stream-function approach which employs a fourth-order partial differential equation. By this approach, the formulation for singularities in the interior of one of two immiscible fluids becomes straight forward.
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    Open Access
    The Coastal Zone of Lagos in Relation to land Resource Development: A study in Applied Geomorphology
    (University of Lagos, 1975-06) Adegboye, Akinseinde
    This thesis is written in two parts. part one examines the environmental setting and the theoretical background to the evolution of the landforms in the coastal zones of Lagos, as well as characteristics of the geomorphological problems in the area. Part two which covers Chapters four to eight examines the techniques used in the study of land resource development in the coastal zone and elucidate the manner in which the data were collected and the use of the data for land classification. Finally, an appraisal of the significance of demorphology to physical planning in general is made.
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    Open Access
    Microbiological Studies of Shrimp Spoilage
    (University of Lagos, 1979) Aribisala, O. A.
    bacterial counts of samples of freshly caught shrimps, Penaeus duorarum and ofm sea water from Nigeria, were carrioed out for a period ofm ten months, from April 1975 to january 1976. A monthly variation in the size of the bacterial populations of shrimps and sea water was observed.
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    Open Access
    An Investigation of N-Complexes from Disubstituted Acetylenes and Copper (I) Compounds.
    (University of Lagos, 1980) Ukwueze, Albert Chukwuemeka
    1-bromo-3methylbut-1-yn-3-ol, 1-bromo-3-methylpent-1-yn-3-ol, 4-hydroxy-4-methylhex-2-tn-nitrile, 1-chloro-3-methylpent-1-yn-3-ol, 4-methyl-2, 3-dienenitrile and 4-methjolxy-2-yn were separately prepared and then, each of them was used as the disubstituted acetylene for complexation with copper (I), cyanide, copper (I) bromide, and copper (i) chloride respectively in dimethyl formide (d.m.f) and then in dimethyl sulphoxide (d.m.s.o) as the solvent in each case.
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    Open Access
    Studies on Fungal Decomposition of Sawdust in Lagos Lagoon.
    (1980-12) Akpata, Tonie Victoria Imade
    The fungi isolated from Lagos lagoon and decomposing sawdust in the lagoon included Aspergillus flavus, Aspergillus fumigatus, Asperghillus gigateus, Aspergillus niger, Aspergillus tamarii, Candida famata, Cladosporium oxysporum, Curvularia geniculata and Debaryomyces hansenii. others are Fusarium solani, Geotrichum candidum, Mucor haemalis, Paecilomyces variotii, Penicillium species, Trichoderma aureoviride and an unidentified basidiomycete. The fungal population of Lagos lagoon varied with season, the population being highest in the rainy season (March - October) when there was increased organic matter content (188mg/l), greaterturbidity (0.3m) and reduced salinity (2.0%).
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    Open Access
    Studies on Microbial Spoilage of Onions (Allium Cepa. L.)
    (University of Lagos, 1981) Oguntuyo, Olusimbo. Olugbo.
    Four micro-organisms were isolated from rotted onion bulbs, purple variety, purchased from markets in the Lagos State of Nigeria. Three of them were pathogenic; they produce soft rot when wound-inoculated into healthy onions bulb. The micro-organisms were identified as Pseudomonas cepacia Buckholder, Candida utills (Henneberg) Lodder and Kreger-Van Rig and Pseudomonas fluorescens Migula; the last being the most pathogenic of the three.
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    Open Access
    A Study of the Reproductive Biology of the Catfish, Chrysichthys Nigrodigitatus (Lacepede) in Nigeria.
    (University of Lagos, 1981-06) Ezenwa, Benard. J.O.
    The catfish, Chrysichthys nigrodigitatus (Lacépède) is widely distributed in Nigeria. Because of its growing importance in fish-farming and its abundance in both fresh and brackish water in Nigeria, some aspects of its reproductive biology were investigated in some details. The study lasted 27 months from October 1978 to December 1980. The monthly histological development and seasonal changes of the ovary and testis were examined. The process of oogenesis was made up of six stages in agreement with the maturity scale of Nikolsky (1963a): stage 1 (immature): consists of very small and spherical oocytes; stage 2 (Resting): shows very slight increases in diameter of oocytes; stage 3 (Naturation): marks the beginning of yolk deposition; stage 4 (almost mature): characterized by abundant yolk materials which fill the oocytes; stage 5 (spawning): egg membranes rupture and allow eggs to lie free in the lumen; stage 6 (spent condition) : consists of ovaries which look like empty sacks. The annual reproductive cycle in the female is divided into five histologically distinct periods: - pre-spawning (October – November) ; Spawning (December – January) ; Post-spawning (February -, March, April); resting (May, June); Maturing (July, August, September). Spermatogenesis was described in five stages: stage 1 Spermatogonia; stage 2: Spermatocytes; stage 3: Spermatids; stage 4: Spermatozoa; stage 5; spent condition. As in the female, there are five periods in the annual reproductive cycle of the male: Pre-Spawning (October to November); Spawning (December to January); Post-Spawning (February, March, April); resting (May, June); Maturing (July, August, September). The spawning habits were investigated. Sexually mature individuals were found only during December thus suggesting that the species breeds only once a year. Sexual maturity in the females was attained when the fish was between 29cm – 32cm total length, while in the males the range was between 30cm – 35cm total length. There were more females than males during the spawning season. Experiments in glass aquaria and concrete tanks confirm that there is pairing behaviour and that spawning could take place in dark hollow cavities with either sandy or muddy bottoms. The monthly examination of Physico-chemical parameters of Badagry lagoon helped to throw more light on the water environment during spawning.
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    Open Access
    "The Biology of the Clupied, Ilisha Africana (Bloch) Off the Nigerian Coast"
    (University of Lagos, 1982-01) Marcus, O.
    Aspects of the biology of Ilisha Africana (Bloch) caught off the Nigerian Coast were studied. These included the taxonomy, distribution, age and growth, food and feeding habits, reproduction and racial studies. The use of meristic and morphometric characters was employed in the taxonomy study. I. africana was widely distributed along the Nigerian Coast within depths of 10 - 50m. The the greatest abundance occurred at depths between 40m and 50m. The size range of the specimens examined was between 4.2, and 28.7cm. Ageing of the species was carried out using the burnt otolith technique and the maximum age attainable was found to be 5 years while the size and age at maturity were 12.0cm and 1 year respectively. Growth was found to be isometric in this species. The food and feeding habits were studied using the numerical, volumetric and frequency of occurrence methods. The major food items of I. africana consisted of crustaceans, fish, Larvae and molluscs. The larger fish fed more on larger food items while the diets of the smaller fishes consisted mostly of the smaller food items. Diets of fishes from shallow depths consisted of a greater variety of good organisms than the diet of fishes from the deeper waters. The occurrence of ripe, ripe running and spent fish in all months of the year indicated that spawning occurred in the species throughout the year. However, higher percentages in the months of June to December and the higher values of the gonadosomatic indices (GSI) from May to December was used in delimiting the peak spawning season. Period of peak spawning coincided with the period of higher condition factors in the species. Fecundity estimates ranged from 2,029 to 11,687 while the egg diameter ranged from 0.57 to 1.35 mm. The gonad maturation stages were classified as immature, ripening 1, ripening 2, ripe, ripe running and spent stages. The histological growth of the ovarian egg was monitored and the stages involved in oogenesis of I. africana were classified as oogonium, primary oocyte, primary vitellogenesis, secondary vitellogenesis, tertiary vitellogenesis, hyaline oocyte, and corpora atretic. A racial study of I. Africana collected from Lagos Coast, off Benin, Brass and Bonny Rivers showed that they were not genetically separable populations. Significant differences were found only in the final counts of specimens off Lagos Coast as compared with the other locations.
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    Open Access
    Methodology of Organic Chemistry Practicals at the Tertiary Level
    (University of Lagos, 1983) Fonche, P.T.
    The quest for the improvement in students’ performance based upon their learning efforts in chemistry has continued unabated. This quest has led to the uncovering of new needs which can ameliorate both the teaching and learning transactions. Derived from theoretical and empirical work, the new Needs, include the enjoyment of practicals, provision in lecture-student interaction, and student involvement in decision taking. The present study is aimed at designing, implementing and evaluating a new laboratory model in organic chemistry at the tertiary level. For this purpose a preliminary survey of organic chemistry practicals at the tertiary level was carried out in 1979 using a questionnaire in five African University to determine the existing teaching modes. Lecturers and students were chosen as subjects for the survey. An evaluation of the questionnaires indicated that the presentation of organic chemistry practicals in the institutions involved was done in a highly structured and elaborate traditional manner. The content and instructions for procedures are precisely written out for the students to follow. In this manner, the need for students to think seemed to be minimal because much of the experimental work was set out in very precise instructions. Students appear not to enjoy this kind of laboratory approach. Besides, student involvement in decision making and lecturer-student interaction tended to be low. There has also been inadequate emphasis placed on learning or reinforcement of principle during organic chemistry practicals .However, this traditional laboratory approach encourages the development of manipulative skills in students. Hence, the semi-structured approach whereby students work on set experiments but for limited guidelines was proposed as an alternative to the structured practicals. The proposal was followed by the design, trial implementation and assessment. This revealed the feasibility of a semi-structured practical in organic chemistry. The trial implementation and assessment yielded positive indications and suitability. The assessment of this design showed its relative merits over the traditional approach.
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    Open Access
    Studies on the Rhizosphere Mycoflora of Celosia Argentea (L) and Hibiscus Esculentus
    (University of Lagos, 1983-01) Igbosuah, E.O
    Rhizosphere studies of two local green vegetables, celosia aregentea Linn and Hibiscus esculentus Linn (new name Abelmoschus esculentus) were studies from vegetative stage to senescence. The viable seeds beds made from sandy loam soil. Samples were collected at two-week intervals at 9.00 hrs in the morning. Morphologically, A. esculentus (okra) had 3 leaves with more dense rooting system at 2 weeks than C. argentea (soko) with 6 leaves. Both plants appeared to reach maturity at the 14th week after planting. Both plants encouraged the growth of fungi and bacteria in the vicinity of their roots due to their secretions inti the soil. In the 14 th and 16th weeks of growth however, when the plants fruits were fully developed, fungal and bacteria populations were repressed. Twenty species of fungi belonging to 9 genera were isolated from non-rhizosphere and rhizoplane of okra while 12 and 9 were obtained from the rhizosphere and rhizoplane of soko. Aspergillus was the dorminant genus isolated. Other genra include penicillium, Trichoderma, Fusarium, Curvularia, Rhizoctonia, Gliocladium, Myrothecium, Scolecobasidium, Botryodiplodia and sterilla mycelia. Biochemical studies revealed that no sugars were detected chromatographically from any of the root exudates. Okra exudate was however found tocontain alanine and glycine while ‘soko’ exudate contained aspartic acid, glutamine and an unidentified amino acid. Most of the isolated fungi were found to grow together in petri dishes without any inhibitions. Trichoderma harzianum Rifai however was found to be antagonistic to Rhizoctonia spp. Studies on this activities of some fungicides showed that thiram (arasan) which was most effective in reducing microbial population in the soil persisted in the garden soil for 35 days after application. A few of the isolated fungi were found in nutritional experiments to utilize carboxy methyl cellulose (CMC) as the sole carbon source
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    Open Access
    Role Perceptions and Role Expectations of Selected Secondary School Teachers in Ondo State of Nigeria
    (University of Lagos, 1983-06) Kupolati, O.C
    This study was designed to investigate the teacher's role perception and the expectation of this role by the teacher and his reference groups in selected secondary schools in Ondo State. A Questionnaire called STRES probed respondents' expectations regarding instructional, social/civic, guidance/counselling, management and personality roles of the teacher. It was hypothesised that there would be no significant differences in teachers' role perceptions and the expectations of such roles by their role sets. The test-retest validity and reliability of the instrument statistically computed yielded coefficient of 0.0976. The study involved 1,625 participants comprising 586 teachers, forty principals, 800 students, 119 educational administrators and eighty parents/guardians - selected randomly from forty secondary schools in Ondo State of Nigeria. The result showed that there was a significant difference in the teachers' perception of their role and the expectation of such role by their reference groups. The teachers differed markedly on many of the items and there was variability and differences amongst the groups on the teachers' role expectation. The findings also revealed: (a) A significant difference between the role perception of teachers and expectation of principals; (b) A significant difference between the role perception of teachers and expectation of students; (c) A significant difference between the role perception of teachers and expectation of parents; (d) A significant difference between the role perception of teachers and the expectation of administrations; (e) A significant difference between the expectation of the role of Ondo State Secondary School teachers by the principals and the expectation of such role by the students; (f) A significant difference in the expectation of the role of Ondo State Secondary School teachers by the parents and the expectation of such role by the administrators; and (g) Partial relationships between the sample teachers' sex, marital status, professional qualifications, school size and school location and their role perceptions. Based on findings, discussions and conclusions, the ensuring implications and recommendations were made: 1. The need for a stronger link between teachers and their reference groups; 2. The necessity for workshops and seminars for school functionaries and reference groups on their different roles and the effective performances of such roles; 3. The desirability for a follow-up study in other sectors of the education system about the school functionaries, using additional variables, and in other states for corroborative purposes; and 4. The need to promote workshops among school personnel and their role referents on role conflict resolution towards greater achievement of school goals and purposes in Ondo State secondary schools.
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    Open Access
    Kinetics of the Reactions of Nitro-Activated Diphenyl Ethers with Substituted Anilines in Benzene.
    (University of Lagos, 1983-11) Ezeani, E. C.
    The kinetics and mechanisms of the reactions of nitro-activated diphenul ethers with substituted anilines in benzene have been investigated. The reactions except that of 2, 6-dinitro phenyl 2,4,6-trinitrophenyl ether are base catalysed. For some of the nucleophiles, the rates decreased with increasing temperature in the range 5 - 350C resulting in negative enthalpies of activation (~HN-4.1 to 20.0 kJmol-1). This can be rationalised in terms of a step-wise mechanism involving (at least) a pre-equilibrium. The catalysis of the mono-nitro substituted diphenyl ethers involves two aniline molecules and proceeds by temperature - independent rates while that of the dinitro substituted ones involve one aniline molecules and proceeds by temperature-dependent rates in the above temperature range. The results are interpreted in terms of a cyclic mechanism assisted in special cases by steric factors.
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    Open Access
    Seasonal Changes of Phytoplankton of Lagos Lagoon and the Adjacent Sea in Relation to Environmental Factors.
    (University of Lagos, 1983-11) Nwankwo, D.I
    Species composition and seasonal changes in the Phytoplankton of Lagoon and adjacent sea from November 1980 to October 1982 were investigated in relation to environmental factors. The physico-chemical parameters exhibited seasonal changes closing related to the pattern of rainfall while difference Phytoplankton assemblages were closely related to the salinity gradient. Phytoplankton assemblages had more diatom species composition in the dry than the wet season. Wet season assemblages were characterised by many pennate diatoms probably dislodged from the benthos during periods of high fresh water discharge but centric forms remained dominant at both seasons. The Phytoplankton of Lagos Lagoon and the adjacent sea belongd to four main algal groups; Bacillariophyceae, Chlorophyceae, Cyanophyceae and Dinophyceae. Qualitative and quantitative changes in the Phytoplankton occurred during the two-year seasonal cycle in responds to environmental changes. Salinity changes were correlated with other physico-chemical parameters in Lagos Lagoon. Fluctuations in species diversity and cell numbers are attributed to changes in salinity and influx of nutrient rich waters. In general, species were more equitably distributed during the dry season but usually much less so at the end of the wet season. Similarity between stations occurred throughout the Lagoon complex in the wet season whereas clear differences occurred in fresh, brackish and marine zones in the dry season.
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    Open Access
    The Biology of the Ten Pounder, Elops Lacerta (Val) In the Freshwater, Estuarine and Marine Environments
    (University of Lagos, 1984-06) Ugwuba, A. O.
    Aspects of the biology of the ten-pounder Elops Lacerta (Val) in the freshwater, brackish and marine habitats were investigated. The investigations covered the taxonomy, racial study, distribution, age and growth, food and feeding habits and reproduction. Work was also carried out on the physicochemical features of the different environments. Meristic and morphometric characters were employed in the taxonomy and racial studies. Juvenile E. Lacerta was widely distributed in the Lekki and Lagos Lagoons while adults existed off the Lagos Coast. The greatest abundance of adult ten-ponders was within depths of 10 - 20m especially in the shallow waters after the harbour entrance. The specimens examined ranged from 5.8 - 24.4cm in Lekki Lagoon, 6.2 - 23.3cm in Lagos lagoon and 16.6 - 34.1cm off the Lagos Coast. Ageing of the species was carried out using the otolith, scale, opercula bone and Pettersen's length-frequency methods. Results from the later show three age groups 0 - 1, 1 - 2 and 2 - 3 years old in the species. The fish spends at least one year in the Lagoons and fish in the 1- 2 and 2 - 3 years old groups existed mainly off the Lagos Coast. The pattern of growth in the three habitats was nearly isometric. The food items consisted of fish, crustacea, insects, and gastropods. E. Lacerta in Lekki Lagoon fed more on fish, in Lagos Lagoon it fed on fish as well as crustacea while those off the Lagos Coast fed more on crustacea mainly shrimps. Insects were detected in stomachs only in Lekki Lagoon while gastropods occurred in stomachs from Lagos Lagoon and off the Lagos Coast. The occurrence of ripe, ripe running and spent fish in all the months indicated that spawning occurred in the species throughout the year. Fecundity estimates ranged from 49,802 - 151,481 while egg diameter ranged from 0.48 - 0.81mm. The gonad maturation stages were classified as immature, immature and developing, ripening (1 and 2) ripe, ripe running and spent stages. A racial study of E. Lacerta showed that though there were slight morphological variations between the populations from the three environments, differences were found to be statistically insignificant indicating that the populations from the three environments were not genetically separable.
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    "Exploratory Behaviour and Food Retrieval Habit of Amitermes Evuncifier Silvestri (Isoptera, Termitidae, Termitinae)"
    (University of Lagos, 1985) Malaka, O. L.
    The study revealed that there was a quantitative recruitment in colonies of Amitermes evuncifer, whenever food was discovered by the scouting foragers. Discovered food stimulated the termites to accelerate their running speed, to and from the food source. Increased trial-laying activity, accelerated movement and carrying of food by the returning workers facilitated recruitment of other Confederates from their nest. These activities equally directed the recruited termites to the food source. Amitermes evuncifer was observed to regulate traffic in relation to the newly discovered food source. The results showed that there was rapid communication between the termites of food source within 3 - 4 minutes. It was further observed that trail to newly found food source did not become dominant over the trail to the already existing food source. The results showed clearly the effect of food on vital activities of termites. The results also showed how trails were established with and without any food source. The two stimulants for strong trail-laying by the termites were found to be: (1) a virgin (trial-less) surface, and (2) a discovered food source. Whenever a food source was discovered, the returning workers (from the food source to the nest) increased strong trail-laying (STL) activity more than the outgoing termites. Results obtained from this work has confirmed that there was no trail specificity (neither in artificial trail extracts nor in natural trails) between different colonies of Amitermes evuncifer. This, of course, means that in trail bioassays, test termites can be taken from any colony (of the same species). A method devised for extracting, preserving as well as carrying out tests with extracted natural trail was discussed. In this study, trail activity was measured in terms of "Internal Trail Unit" (ITU). The trail activity of a single worker sternal gland was found to be 15,000 ITU. This is the highest activity ever found in a worker of any termite species. The morphology and histology of the Sternal gland were investigated and described in some detail. Food preference experiments carried out concurrently in the field and in the laboratory, showed the range of food preference t be divergent in the two areas in another series of experiments it is shown that recruitment was directly proportional to the quantity of food discovered by the scouts. Finally, this study has provided a better understanding of the strategies employed by A. evuncifer in the exploration and retrieval of food.
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    Studies in the Synthesis of Long Chain Aliphatic Compounds.
    (University of Lagos, 1985-03) Hogan, Ephraim-Bassey
    Studies in the synthesis of long chain compounds. This thesis is in two parts. Part 1 involves a study of the straight chain alkanes containing many carbon atoms. These are important analogues of polyethylene, a versatile industrial raw material. Although they can be derived from natural fats or waxes or from ethylene oligomers, they are never obtained pure. The physical properties of linear polyethylenes can be better understood if pure paraffins of comparable chain length could be synthesised and analysed. Here long chain aliphatic compounds with butyl side chain which could be used as models for low density polyethylene have been synthesised. The method employed was first proposed by M.O whitiny et al. The original schemes are reviewed. By this approach a number of long chain aliphatic compounds with a butyl branch had been synthesised.
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    Transport and Metabolism of Adenosine in Trypanosoma vivax
    (University of Lagos, 1986) Okochi, I.V
    Transport metabolism of adenosine have been studied in Trypanosoma vivax. In the transport studies, it was found that adenosine uptake was inhibited by different antimetabolites. Phlorizin, coformycin and formycin A produced approximately the same level of inhibition more than ouabain while ouabain inhibited more than iodoacetate. Guanosine stimulated adenosine uptake considerably but neither thymidine nor inosine had any appreciable effect. Results of the time course assay and uptake studies of various concentrations of adenosine suggest that possibly more than one mode of uptake operates in the transport of adenosine in T. vivax. In the metabolic studies, it was observed that adenosine was converted to inosine, hypoxanthine, adenine and nucleotides in whole cells, crude cell extracts and isolated membranes of T. vivax. The major product formed, under the conditions of the present studies, was inosine. Coformycin inhibited the conversion of adenosine to inosine suggesting the presence of adenosine deaminase in this parasite. Formycin A inhibited appreciably the incorporation of 14C-adenosine into nucleic acids in intact cells of T. vivax. It also inhibited the conversion of adenosine to inosine in crude cell extract. The mechanism of action is not definite but probably, formycin A is a substrate to the deaminase in this microorganism. The conversion of inosine to hypoxanthine was stimulated in the presence of exogenous inorganic phosphate. The conversion of hypoxanthine to inosine was increased slightly by the addition of ribose-1-phosphate to the reaction medium, indicating the existence of the action of purine. Nucleoside phosphorylase. In addition, inosine was converted to hypoxanthine in the absence of exogenous inorganic phosphate, suggesting the presence of purine nucleoside hydrolase activity. The data obtained in these studies suggest that adenosine metabolism in T. vivax mimicks that of the mammalian cells. However, differences could exist in the nature of the enzyme systems.
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    Application of Liquid Filters to Photothermal / Photoquantum Solar Energy Conversion
    (University of Lagos, 1986) Chendo, C.A.M
    This thesis discusses the development, design, fabrication and testing of spectrally selective beamspliting absorption filters (AF-SSBS) which can decouple quantum and thermal convertors to improve conversion of the total solar spectrum to useful energy. These components separate the solar spectrum into regions or windows matched to the spectral response of the specific photoquantum process and the balance used for photothermal convertor. Higher conversion efficiencies can then be maintained in the photoquantum covertor while the other photons are directed to a thermally decoupled loop at an elevated temperature. Various AF-SSBS developed for hybrid photoquantum/photothermal systems employing silicon cells as the PQ convertors are discussed in terms of their applicability, flexibility and performance. By changing the filter medium concentration (for inorganic salts), optical path length and appropriate glass channel a variety of spectrally selective filters can be tailored to match system performance. Both simplified and detailed performance analyses using moderately concentrated solar radiation showed enhanced overall performance. Preliminary studies have had the following results: (1) 1. The AF-SSBS permits maximum possible PQ conversion efficiency while at the same time permitting high temperature thermal collection. This concept allows the optical quantum receiver to operate at the low temperatures with the greatest efficiency. (2) 2. Realistic performance evaluation requires the knowledge of the spectral distributions of the irradiance source at the time of measurement. There is also the need to spectrally characterize both the solar cell and the irradiance concentrating device. (3) 3. Parametric and design studies suggest that for good PQ/PT performance spectralirradiance measurements must be made at various geographical locations over extended periods. Such data will contribute to models that match PQ materials to different spectral profiles to maximize device performance. (4) 4. Knowledge of heat transfer mechanisms between the various AF-SSBS and PV cells/modules and the determination of optimum flow rates are necessary for optimization of the system performance. (5) Changes in the demand for electrical and thermal energy at design conditions can be met by varying the type of absorption filter, concentration, and photoquantum convertor. The result of the analysis suggests that cobalt sulfate in an appropriate glass channel could be ideal for low-temperature applications (< 1000C) while the heat transfer and related fluids in appropriate cells could serve as medium-temperature applications ( < 2000C) where high thermal energy output is required.
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    Effects of Oral Contraceptive Agents on some Vitamins in Rats fed on selected Nigerian Diet
    (University of Lagos, 1988) Magbagbeola, O.A
    Oral contraceptive agents (OCA) have been in use for well over two decades with a total of 150 to 200 million women all over the world using the pills as means of birth control. Aside from their gynecologic influences, the hormones have been shown to affect metabolic and nutritional processes. Concern over the nutritional status of Nigeria females consuming OCA prompted this research using animal model.Four vitamins were investigated along with four birth control pills-ovral, Nordette, pure progestogen (Norgestrel) and pure Proestrogen (Ethinylestradiol). The injection of the contraceptive gestroids effect depression of physiological levels of plasma B-carotene, cellular retinol binding protein (CRBP), liver vitamin A, plasma vitamin B6 significantly (P < 0.005), while the effect on animal weight, food consumption, plasma vitamin A, plasma retinol binding protein (PRBP), showed an increase in level when compared to that of the control. With respect to x-tocopherol (vitamin E) level, there was decrease in plasma concentration for the first 30 days of administration, while an increase in concentration was observed in the last 30 days of administration of the pills. The oestrogen components of the pill was found to be responsible for the effect on the vitamins, although the progestrogen contributes but the effect was not significant.