Showing papers by "University of Nigeria, Nsukka published in 1990"
Book•
01 Jan 1990TL;DR: This companion volume explains in depth the meaning, or semantic theory, of ML.
Abstract: The full mathematical description of the functional programming language ML was given in Milner, Tofte, and Harper's Definition of Standard ML. This companion volume explains in depth the meaning, or semantic theory, of ML.
173 citations
TL;DR: In this paper, three soils which had been amended for several years with pig slurry, cattle slurry and sewage sludge were dry-sieved to obtain microaggregates in the size range of 250-125, 125-50, and <50 μm.
Abstract: Three soils which had been amended for several years with pig slurry, cattle slurry, and sewage sludge were dry-sieved to obtain microaggregates in the size range of 250–125, 125–50, and <50 μm. With amendments, aggregate size distribution of whole soils was shifted to larger sizes, especially for the most fragile soil, whereas percent content of microaggregates decreased except for the lower size aggregates of the fragile soil. Particle size distribution of microaggregates revealed an increase in percent sand and a reduction of percent silt and clay in the <50 μg size fraction for all soils. These results showed the aggregation effect induced by the organic waste additions. Aggregate stability of microaggregates revealed significant correlation with humic substances content (humic acids alone and humic plus fulvic acids) and non significant with total organic matter substantiating the belief that humic substances are the predominant binding agents in this aggregation range. Molecular weight distribution of humic acids extracted from microaggregates of unamended soils demonstrated that the lower the soil aggregate size distribution, the larger the contribution of the high molecular weight fraction. All microaggregates from amended soils showed a progressive increase of the high molecular weight humic acids with decreasing size, reaching a maximum in the <50 μm fraction. In this aggregate size a parallel enhancement of the aggregate stability was also evident. It is concluded that a close relationship exists between aggregate stability and high molecular weight humic substances. Additions to soils of organic material containing high molecular weight constituents would represent a useful management practice to improve aggregate stability.
134 citations
TL;DR: The dried leaves of Morinda lucida were extracted with 50% methanol and the extract was recovered in a 9.7% w/w yield and significantly suppressed the level of parasitemia after Trypanosoma brucei infection in mice.
97 citations
TL;DR: The overall trend in helminthosis in these animals was that of an escalating worm burden during the period of confinement and a low worm burden when animals were allowed free range and these periods corresponding to the cropping and harvest seasons respectively.
Abstract: The epidemiology of helminth infections in West African dwarf sheep and goats under the traditional husbandry system prevailing in the derived savanna area of eastern Nigeria was studied for 12 months. The infections observed were due to Haemonchus contortus (87.1%), Trichostrongylus spp. (63.8%), metacestodes of Taenia hydatigena (30.2%), Oesophagostomum columbianum (22.4%), Strongyloides sp. (18.8%), Cooperia spp. (17.2%), Gaigeria pachyscelis (6.0%), Moniezia expansa (6.0%), Bunostomum trigonocephalum (4.3%), Trichuris ovis (3.5%), Capillaria sp. (0.9%) and paramphistomes (0.9%). Mixed infections were most prevalent. The endemicity of parasitic gastroenteritis in the area was indicated by the high prevalence of the helminths irrespective of the season of the year. The overall trend in helminthosis in these animals was that of an escalating worm burden during the period of confinement (April – October) and a low worm burden when animals were allowed free range (November – March), these periods corresponding to the cropping and harvest seasons respectively. A strong positive correlation (r=0.73; p<0.01) was obtained between the mean strongyle worm burden and the eggs per gram (EPG) of faeces. A single treatment with a broad spectrum anthelmintic followed by movement into clean sheds at the beginning of confinement is suggested to give control of helminthosis in small ruminants in this area.
93 citations
TL;DR: In this article, it was shown that for arbitrary x 0 ϵ X, the sequence x n + 1 = (1 − C n )x n + C n SX n, n ⩾ 0 converges strongly to the unique solution of Tx = f.
81 citations
TL;DR: Dioscoretine isolated from the aqueous fraction of the methanol extract of Dioscorea dumetorum tubers when administered intra-peritoneally to normal and alloxan diabetic rabbits produces significant hypoglycaemic effects at a dose of 20 mg/kg.
Abstract: Dioscoretine isolated from the aqueous fraction of the methanol extract of Dioscorea dumetorum tubers when administered intra-peritoneally to normal and alloxan diabetic rabbits produces significant hypoglycaemic effects at a dose of 20 mg/kg. The fasting blood sugar in normoglycaemic rabbits was reduced from 112 mg/100 ml to 55 mg/100 ml after 4 hours. In alloxan diabetic rabbits, the blood sugar was lowered from 520 mg/100 ml to 286 mg/100 ml at the same time interval. The aqueous fraction of the methanol extract produced comparable effects at 100 mg/kg. The chloroform fraction of the same extract raised the fasting blood sugar of normal rabbits to 196 mg/100 ml after 6 h. The acute toxicity studies gave LD50 values of 1.4 g/kg for the aqueous fraction and 0.58 g/kg for dioscoretine when tested on mice. The hypoglycaemic effects were compared to those of tolbutamide.
65 citations
01 Jan 1990
TL;DR: The steam distilled essential oil of Hyptis Suaveolens Yielded 32 terpenoid compounds When Subjected To Gc/Ms Analysis as mentioned in this paper, The Compounds were Identified From Their Retention Times, Mass Spectral Fragmentation Patterns and Correlation with Database Ms Data.
Abstract: Steam Distilled Essential Oil Of Hyptis Suaveolens Yielded 32 Terpenoid Compounds When Subjected To Gc/Ms Analysis. The Compounds Were Identified From Their Retention Times, Mass Spectral Fragmentation Patterns and Correlation With Database Ms Data. Limonene; Thujane; α-Pinene; α-Phellandrine; 3-Cyclohexen-L-ol; 4-Methyl-L-(L-Methyl Ethyl)-3-Cyclohexen-L-ol; 3-Cyclohexen-1-Carboxyaldehyde; Elemene; 4, 11, 1 L-Trimethyl-8-Methylene Bicyclo [7.2.0] Undec-4-Ene; Octahy-Dro-1, 4-Dimethylazulene; 5α, 8β, H-9β, H-10a- Labd-14-Ene; 5α-Androst-9(L L)-En-12-One and 5α-Androstan-2,11-Dione Were The Major Components Identified. The Essential Oil Inhibited The Growth Of Both Gram-Positive and Gram-Negative Bacteria As Well As Having Mild Antifungal Activity.
58 citations
TL;DR: In this paper, the effects of coal and charcoal on solar-still performance were studied and the average daily productivity and efficiency of the still were 1.121/m2 and 16.5% respectively.
56 citations
TL;DR: In this paper, the long-term effects of organic wastes on dry aggregate size distribution and on the C, N and available-P concentrations within the different aggregate fractions of some agricultural soils in North-Central Italy were evaluated.
54 citations
TL;DR: Applying equilibrium dialysis, plasma protein binding of ivermectin was measured in five healthy individuals and it averaged 93.2±4.4% (SD).
Abstract: Human pharmacokinetic data on the new anti-parasitic agent, ivermectin, are scanty. For the evaluation of its disposition a specific HPLC assay with sensitive fluorescence detection was developed. Applying equilibrium dialysis, plasma protein binding of ivermectin was measured in five healthy individuals and it averaged 93.2 +/- 4.4% (SD). Such strong binding should be taken into consideration, especially in patients with malnutrition or with diseases in which a decrease in plasma proteins and consequently a higher free fraction of ivermectin could be expected.
52 citations
01 Jan 1990
TL;DR: The Ethanolic Root Extract Possessed Significant Dose-Dependent Anti-Ulcer Activity In Experimentally-Induced Acute Gastric Ulcers With Indomethacin and Cold Stress.
Abstract: The Ethanolic Root Extract Of Combretum Dolichopetalum Induced Dose-Dependent Relaxation Effect On The Isolated Guinea Pig Ileum With An Ec5o Of 2.65 Mg/Ml, and Also Inhibited Contractile Responses Of The Ileum To Histamine (10/μg/Ml) and Acetylcholine (10/μg/Ml). The Extract Possessed Significant Dose-Dependent Anti-Ulcer Activity In Experimentally-Induced Acute Gastric Ulcers With Indomethacin and Cold Stress. The Anti-Ulcer Effect Of The Extract Could Be Due To Its Content Of Tannin and Saponin Or To Its Anticholinergic and Antihistaminic Activities, Or A Combination Of These Factors.
TL;DR: Variations in the important microbial groups involved and their metabolic products were studied and it was found that Titratable acidity increased gradually until the end of the fermentation while the total soluble solids and pH declined.
Abstract: Obiolor is an acidic non-alcoholic beverage prepared by fermenting sorghum and millet malts. The traditional process for the production and microbiological characteristics of the beverage were investigated. Bacillus spp., Lactobacillus plantarum and Streptococcus lactis were the associated micro-organisms most actively involved. Yeasts were present in low numbers towards the end of the fermentation. Other micro-organisms isolated did not appear to play a role in the fermentation process. Variations in the important microbial groups involved and their metabolic products were studied. Titratable acidity increased gradually until the end of the fermentation while the total soluble solids and pH declined. Acetobacter spp. were probably responsible for the unacceptability of the product after 24 h.
TL;DR: In this article, the agronomic potential of brewers' spent grains (BSG) was evaluated on two texturally contrasting tropical soils, using a split-plot design with three replications.
TL;DR: Kolaviron, a mixture of Garcinia biflavonoids obtained from Garcinia kola, protected rats against the toxic effects of thioacetamide in vivo and reduced the thiopental‐induced sleep in thio acetamide‐poisoned rats, both in the chronic and acute test models.
Abstract: Kolaviron, a mixture of Garcinia biflavonoids GB-1 (II-3-I-4′-II-4″-I-5-II-5-I-7-II-7-heptahydroxy-3,8″-biflavanone), GB-2 (II-3-II-3′-I-4′-II-4″-I-5-II-5-I-7-II-7-octahydroxy-3,8″-biflavanone) and kolaflavanone (II-3-II-3′-II-4″-I-5-II-5-I-7-II-7-heptahydroxy-3,8″-biflavanone) obtained from Garcinia kola, protected rats against the toxic effects of thioacetamide in vivo. The biflavonoid mixture at a dose of 100mg/kg i.p. reduced the thiopental-induced sleep in thioacetamide-poisoned rats, both in the chronic and acute test models. The microsomal enzyme levels in the serum of rats poisoned with thioacetamide were also significantly altered by treatment with kolaviron.
01 Jan 1990
TL;DR: In this article, the antimicrobial activity of a spirostanol saponin (DM-1), isolated from the fruit pulp of Dracaena mannii, was investigated against 17 species of fungi and 4 of bacteria.
Abstract: The antimicrobial activity of a spirostanol saponin (DM-1), isolated from the fruit pulp of Dracaena mannii, was investigated against 17 species of fungi and 4 of bacteria. DM-1 showed strong antifungal activity and weak antibacterial activity within the concentration range of 6.25-10, 000 μg/ ml. The structure of DM-1 was characterized as 3β-0-[(α-L-rhamnopyranosyl (1 ← 2), α-L-rhamnopyranosyl (1←3))-β-D-glucopyranosyl]-17 α-hydroxyl-spirost-5-ene from the analysis of the spectra data and chemical reactions.
TL;DR: Incorporation of 1% (v/v) of Tween 80 in culture medium enhanced enzyme production while the presence of fatty acids reduced both fungal growth and lipase production and the enzyme showed broad substrate specificity.
Abstract: The optimum cultural conditions for the production of lipase byA. strictum under stationary condition are: period of incubation, 7 days; temperature, 30°C; xylose at a concentration of 2% (w/v) and 3.5% (w/v) soyabean meal as carbon and nitrogen sources respectively. Incorporation of 1% (v/v) of Tween 80 in culture medium enhanced enzyme production while the presence of fatty acids reduced both fungal growth and lipase production. The enzyme showed broad substrate specificity.
Journal Article•
TL;DR: The findings suggest that horizontal transmission aided by cultural or behavioural factors and clustering of carriers rather than transfusions is the main determinant of HBV prevalence in rural Nigeria.
Abstract: Hepatitis B virus markers were measured by radioimmunoassay in the sera of 804 rural and urban inhabitants and prisoners in Nigeria. Of these, 530 (66%) subjects had one or more serologic markers of HBV infection; 9.1% were HBsAg carriers, 47% had anti-HBs and 10.1% were positive for anti-HBc alone. Total HBV exposure rate, HBsAg carrier rate and previous exposure to hepatitis B virus measured by the frequency of anti-HBc alone were significantly higher in the rural population compared with the urban population (p less than 0.0001; p less than 0.03; p less than 0.01) respectively. It was observed that by the age of 40 years, 87% of the Nigerian population have at least one HBV seric marker. There was a higher incidence of HBsAg (p less than 0.0001) and anti-HBc alone (p less than 0.001) in prisoners than in any other group. HBeAg was present in 16.4% HBsAg positive individuals with no intersex difference. No positive correlation was found between the frequency of HBV markers in rural dwellers and the history of blood transfusions. These findings suggest that horizontal transmission aided by cultural or behavioural factors and clustering of carriers rather than transfusions is the main determinant of HBV prevalence in rural Nigeria.
TL;DR: In the present study, the hypoglycemic agent of this plant is isolated by bioassay-guided fractionation of the methanolic extract by bioASSay- guided fractionation in order to establish a phytochemical profile of the extract.
Abstract: In the present study, we have isolated the hypoglycemic agent of this plant by bioassay-guided fractionation of the methanolic extract
TL;DR: A survey was conducted in the Nigerian derived savanna on the seasonal fluctuations in the composition of Haemonchus contortus burden of naturally infected West African Dwarf sheep and goats, finding that higher burdens were evident during the rainy rather than the dry season.
Journal Article•
TL;DR: The data suggest that impotence is very common among the authors' male medical out-patients, particularly the elderly and middle-aged, the hypertensives on drug therapy and the diabetics.
Abstract: Erectile failure is commonly overlooked by most doctors while conducting clinical interviews. This is probably, in part, explained by the widespread belief within the medical profession that the disorder is mostly psychogenic and probably uncommon in a variety of patient populations. In order to define the frequency and pattern of this disorder in our local clinic population, the present study has determined the incidence of erectile failure in 227 adult male medical out-patients of the University of Nigeria Teaching Hospital, Enugu. Seventy-seven (34%) of the patients were impotent and the incidence increased progressively with age. Only 26% of the impotent patients volunteered information on the disorder without specific questioning. Diabetics had a significantly higher incidence of impotence than the non-diabetics (58% vs. 29%; P less than 0.0001). Among the hypertensives, drug therapy increased the frequency from 8 to 61%. These data suggest that impotence is very common among our male medical out-patients, particularly the elderly and middle-aged, the hypertensives on drug therapy and the diabetics. The disorder should be actively sought out since most affected patients do not complain about it.
01 Jan 1990
TL;DR: Results suggest that the hemostatic action of E. odoratum may be partly due to a-receptor mediated vasoconstriction, and the extract-induced contractions were blocked by low concentrations of prazosin but not by atropine, propranolol, mepyramine or pimoxide.
Abstract: The pressed extract of the leaves of Eupatorium odoratum is popularly employed traditionally to arrest bleeding from cuts and for wound dressing. Preliminary investigations showed that the leaf extract of E. odoratum significantly reduced bleeding time in guinea pigs and rabbits. The effect was traced largely to its vasoconstrictor activity similar to that of adrenaline. In vitro studies showed that the extract concentration-dependently contracted both the rat and guinea pig vasa deferentia and rabbit arterial strips while having no effect on isolated guinea pig ileum and rat stomach strip preparations. The extract-induced contractions were blocked by low concentrations of prazosin but not by atropine, propranolol, mepyramine or pimoxide. These results suggest that the hemostatic action of E. odoratum may be partly due to a-receptor mediated vasoconstriction.
TL;DR: In this paper, the authors examined the effect of solvent polarity on oil yield and oil properties, including acid number, iodine value and color intensity determinations, and found that the equilibrium extracting capacity of each solvent was dependent on two factors, namely, the nature of the oil and the polarity of the solvent.
Abstract: Solvents of differing dielectric constant were used to extract oils from the seeds of: rubber [Hevea brasiliensis (Kunth) Muell. Arg.], melon [Colocynthis vulgaris Schrad], fluted pumpkin [Telfairia occidentalis Hook f.] and oilbean [Pentaclethra macrophylla Benth]. The aim was to examine the effect of solvent polarity on oil yield and oil properties. The oils were extracted under Soxhlet conditions with the following solvents: petroleum benzene (60–80°C), cyclohexane, isopropyl ether, ethyl acetate, tetrahydrofuran, propan-2-ol and acetone. The oils were characterized by acid number, iodine value and color intensity determinations. The oil yields of each seed in different solvents ranged as follows: 58.0–64.4% (pumpkin), 56.1–59.1% (melon), 40.6–48.8% (rubber) and 35.4–43.3% (oilbean). The equilibrium extracting capacity of each solvent was found to depend on two factors, namely, the nature of the oil and the polarity of the solvent. Both factors were found to determine the acid number, iodine value and color intensity of each oil.
TL;DR: In this article, the authors studied the problem of iterative solution of nonlinear equations of the dissipative type in a real Banach space with a uniformly convex dual and showed that the solution converges strongly to a solution of x + Tx = f in K. Explicit error estimates are also computed.
Abstract: Let E be a real Banach space with a uniformly convex dual, and let K be a nonempty closed convex and bounded subset of E. Suppose T:K → K is a continuous monotone map. Define S:K → K by Sx = f-Tx for each x in K and define the sequence {x n { iteratively by x o ∈K, x n+1 = (1-C n )x n +C n Sx n , n ≥ O, where {C n { ∞ n=o is a real sequence satisfying appropriate conditions. Then, for any given f in K, the sequence {x n { converges strongly to a solution of x + Tx = f in K. Explicit error estimates are also computed. A related result deals with iterative solution of nonlinear equations of the dissipative type
TL;DR: In this paper, a passive radiative cooling system was designed, constructed and tested under clear skies, and the results indicated that the system has a great potential for providing a cold storage facility in developing countries and in remote areas.
TL;DR: It is concluded that diagnosis of Typhoid fever by the Widal test alone is prone to error, and that any claims of a typhoid fever epidemic in Nigeria remain mere conjecture.
Abstract: In the last 2 years, there has been public panic across Nigeria about an epidemic of a 'killer' febrile disease, purportedly typhoid fever. The evidence for this epidemic is reviewed in the light of appropriate diagnosis of typhoid fever. All the patients were diagnosed as typhoid fever, primarily based on Widal test results. Investigations in the hospital of 15 patients confirmed malaria in 70% who, though failing to respond to chloroquine, promptly responded to treatment with Fansidar (sulfadoxine + pyrimethamine). Fever in the remaining 30%, without evidence of malaria and who failed to respond to chloroquine, Fansidar and antibacterials including chloramphenicol, remitted spontaneously. The merits and limitations of the Widal test are discussed. It is concluded that diagnosis of typhoid fever by the Widal test alone is prone to error, and that any claims of a typhoid fever epidemic in Nigeria remain mere conjecture. Misuse of the Widal test and, subsequently, misuse of the antibiotic chloramphenicol, should be very strongly condemned.
TL;DR: In this paper, the authors extracted oil from the seeds of rubber [Hevea brasiliensis (Kunth) Muell] and melon [Colocynthis vulgaris Schrad] using different solvents at varying temperatures.
Abstract: Oils were extracted from the seeds of rubber [Hevea brasiliensis (Kunth) Muell. Arg.] and melon (Colocynthis vulgaris Schrad) using different solvents at varying temperatures. The objective was to determine temperature coefficients (n) for enhanced oil removal and the enthalpy changes accompanying the extraction process.
TL;DR: It is concluded that the bursa of Fabricius is not essential for the establishment of an IBDV infection but is required for the clinical infection.
Abstract: Summary Embryonally bursectomised and nonbursectomised chickens were infected with infectious bursal disease virus (IBDV) at 36 days of age. Neither clinical signs nor gross lesions were observed in the infected, bursectomised (IB) chickens. No significant changes were observed in carcass, thymus or spleen weights of IB and noninfected bursectomised chickens. A mild lymphocytic necrosis and depletion were found in the spleen, thymus and caecal tonsil of the IB chickens. Neither precipitating nor serum neutralising antibodies were detected in the sera but IBDV was reisolated from the spleen and thymus. Infected, nonbursectomised (IN) chickens developed severe depression with diarrhoea and high mortalities. Haemorrhages were found in the muscles of the breast and thigh, proventriculus and intestines. Significant changes were observed between the carcass, thymus and bursa weights of the IN and noninfected, nonbursectomised chickens. There was severe lymphatic necrosis of the bursa, thymus, spleen and caecal ...
TL;DR: In the developing African countries, labor may be safely allowed in a selected group of women who have had one previous cesarean section, and most of them will deliver vaginally with considerable savings in medical cost.
TL;DR: In the Nigerian Basement Complex, the metamorphic grade ranges from middle greenschist facies (400°C) through medium (530-560°C), to upper amphibolite facies(680-750°C); pressure, during metamorphism, varied from low (2 to 3 Kbar) for the andalusite-sillimanite type to high (7 to > 9 Kbar).
TL;DR: There is no short term solution to the problem of land degradation and immediate steps should at least be taken to give legal protection to those who are forced to cross international borders because of drought and famine.
Abstract: This article documents the potential for inter-state conflict in the migration of hundreds of thousands of famine refugees across international borders in West Africa. Nigeria and Ghana, for example, have to deal not only with the effects of land degradation in their northern territories but also with the influx of famine victims from Mali, Niger, Chad and Burkino Faso. These migrations put an enormous extra burden on the fragile and already overstretched social and economic infrastructures of the host countries. The construction of dams for irrigation and electricity generation in international river basins, is another cause of inter-state conflict related to land degradation. The capacity of West African states to find peaceful solutions to these problems is being undermined by the increasing impoverishment and marginalisation of their populations. A self-serving neo-colonialist governing elite is caught in the economic stranglehold of the advanced capitalist nations. While there is thus no short term solution to the problem of land degradation, immediate steps should at least be taken to give legal protection to those who are forced to cross international borders because of drought and famine.