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Item Intermolecular Vibrational Coupling Associated With the 2 Nu 2 Features of the Raman Spectrum of Strontium Nitrate(1987) Kettle, S. F. A.; Lugwisha, Esther H. J.; Vorderwisch, P.; Eckert, JuergenThe method of mixed isotopic crystal Raman spectroscopy shows no evidence for intermolecular vibrational coupling in dl-α alanine; the same method reveals coupling on the N-deutero analogue.Item Intermolecular Vibrational Coupling in Glycine(Elsevier, 1989) Kettle, S. F. A.; Lugwisha, Esther H. J.; Eckert, Juergen; McGuire, Nancy K.A study of isotopomers of α-glycine by Raman, inelastic neutron scattering and i.r. methods reveals intermolecular vibrational coupling on modes which, superficially, appear vibrationally insulated.Item Seaweeds as Heavy Metal Pollution Indicators(1989) Wekwe, W. W.; Othman, Othman C.; Khan, M. R.Item Intermolecular Vibrational Coupling in Dl-Α Alanine and Its N-Deutero Isotopomer(Elsevier, 1990) Kettle, S. F. A.; Lugwisha, Esther; Vorderwisch, P.; Eckert, JuergenThe method of mixed isotopic crystal Raman spectroscopy shows no evidence for intermolecular vibrational coupling in dl-α alanine; the same method reveals coupling on the N-deutero analogue.Item Influence of Sample Particle Size and Heating Rate on the Thermal Decomposition of K2C2O4(Kluwer Academic Publishers, 1991) Mulokozi, A. M.; Lugwisha, Esther H. J.The thermal decomposition of K2C2O4 in a current of dry nitrogen according to the reaction (1) $$K_2 C_2 O_4 \to K_2 CO_3 + CO$$ is shown to be influenced profoundly by the sample particle size and the heating rate. For finely ground samples, a lower activation energy (E a =255.15±5 kJ mol−1) is obtained as compared with the 312.6±6 kJ mol−1 observed for crystal chips weighing 30–40 mg. The characteristic temperatures (the reaction start, peak and end temperatures) are markedly reduced by fine grinding. High heating rates tend to separate the thermal decomposition process into two kinetic phases, shown by splitting of the DTG peak. The significance of these observations is discussed, and the results are theoretically accounted for.Item Activation Energy of Thermal Decomposition of LaC2O4Br(Kluwer Academic Publishers, 1991) Lugwisha, Esther H. J.; Mulokozi, A. M.; Masabo, M. K. J.The activation energy of the thermal decomposition of finely ground LaC2O4Br was determined according to the method of Ozawa asE a=203.83 kJ mol–1. As compared to the value for the parent oxalate La2(C2O4)3 E a=130 kJ/mol), this value is higher by about 70 kJ/mol, which is consistent with the increased interaction between the metal and oxalate ions. The substitution of Br by Cl does not affect the decomposition kinetics profoundly.Gem der Methode von Ozawa wurde die Aktivierungsenergie der thermischen Zersetzung von fein zermahlenem LaC2O4Br mitE a=208.83 kJ/mol bestimmt. Beim Vergleich mit dem entsprechenden Wert fr die Mutterverbindung La2(C2O4)3 (E a=130 kJ/mol) erweist sich dieser Wert um etwa 70 kJ/mol hher, was mit der verstrkten Wechselwirkung zwischen Metall- und Oxalationen bereinstimmt. Der Ersatz von Br durch Cl hat keinen tiefgreifenden Einflu auf die Kinetik der ZersetzungItem Tanzanene, A Spiro Benzopyranyl Sesquiterpene From Uvaria Tanzaniae Verdc(1991-08) Weenen, Hugo; Nkunya, Mayunga H.H.; Mgani, Q.A.; Posthumus, Maarten A.; Waibel, Reiner; Achenbach, HansItem Antimalarial Activity of Tanzanian Plants and Their Active Constituents: The Genus Uvaria 1(1991-08) Nkunya, Mayunga H.H.; Weenen, Hugo; Bray, Dorothy; Mgani, Quintino A.; Mwasumbi, L. B.Item New Aspects of the Decomposition Kinetics of Calcite, Part-I. Isothermal Decomposition(Elsevier, 1992-01) Mulokozi, A. M.; Lugwisha, Esther H. J.Under experimental conditions which tend to minimise the effects of heat and mass transfer, the kinetics of the decomposition of calcite according to CaCO3(s) CaO(s) + CO2(g) is split by the restriction of CO2 transport at the degree of conversion αt when the channels in the CaO(s) surrounding the reactant provide the only diffusion path. Because of the resulting convective cooling beyond αt, the phase boundary reaction proceeds initially with the reaction-only activation energy Ea(1) = 192.89 kJ mol−1 up to αt, after which the reaction proceeds with an apparent activation energy of Ea(2) = 210.33kJ mol−1. The diffusion-controlled reaction proceeds with the mean value of the activation energy Ea(D1) = 0.5 (Ea(1) + Ea(2)) = 201.65 kJ mol−1. The activation energies differ by the same amount, i.e. Ea(D1) − Ea(1) = Ea(2) − Ea(D1) = 8.72 kJ mol−1, equivalent to the degenerate deformation vibration v4 = δ(O-C-O) of calcite observed at 706 cm−1 (infrared) and 714 cm−1 (Raman), which for a transition state sensitive to the instantaneous transport of CO2, complements the cage effect exercised by the lattice, thus giving strong evidence supporting our mechanistic interpretation of the decomposition kinetics.Item Symptomatic Cortical Irregularities of the Distal Femur Simulating Malignancy(1994-09) Craigen, Michael; Bennet, Grace; MacKenzie, J. R.; Reid, RWe reviewed the records and radiographs of seven children who presented with knee pain, local tenderness over the medial femoral condyle, and radiological irregularity of the distal medial metaphysis of the femur suggestive of malignancy. In the five patients who had biopsies, histological changes were consistent with musculotendinous avulsion, and the dissection of ten cadavers confirmed the site to be the insertion of part of the adductor magnus. The recognition of this lesion and knowledge of its benign nature may avoid unnecessary anxiety and needless biopsy.Item Children’s Proximal Phalangeal Neck Fractures with 180° Rotational Deformity(1995-06) Newington, D. P.; Craigen, Michael; Bennet, GraceFive patients under 4 years of age with 180 degrees rotational deformity of a proximal phalangeal neck fracture are described. All cases resulted from a direct shear force to the bone coupled with a sharp withdrawal reaction of the hand. All of the children were successfully treated with open reduction and internal fixation but only after fruitless attempts at closed manipulation and an initial lack of recognition of the severity of the fracture. Each child achieved a full functional recovery of the finger with clinical and radiological union at 4 weeks.Item Stereoselective total syntheses of conduritols-F and -A from tricyclo[6.2.1.0 2 , 7 ]undeca-4,9-dien-3,6-dione(1995-06) Mgani, Quintino A.; Klunder, Antonius J.H.; Nkunya, Mayunga H.H.; Zwanenburg, BinneItem Levels of Crude Proteins and Some Inorganic Elements in Selected Green Vegetables of Dar es Salaam(Association of Food Scientists and Technologists, 1997) Raja, T. K.; Othman, Othman C.; Bahemuka, T. E.Eight green vegetables commonly grown in Dar es Salaam were analyzed for their contents of crude proteins, 4 macro minerals (Mg, K, Ca and Na) and 7 heavy metals (Pb, Cd, Zn, Cu, Mn, Cr and Fe). The values of crude proteins ranged between 1.03-5.23% on fresh weight. These vegetables were found to be rich in macro minerals. The levels of Pb and Cd in some vegetables were above the permissible limits recommended by FAO/WHO. Overall data have, however, indicated that consumption of these vegetables is unlikely to pose any health hazard to the consumer, as these vegetables are good sources of some other essential elements.Item Catalysis of the Knoevenagel reaction by γ-aminopropylsilica(1997-12) Macquarrie, Duncan J.; Clark, James H.; Lambert, Arnold; Mdoe, James; Priest, AndrewThe Knoevenagel reaction can be catalysed by γ-aminopropylsilica. Reactions are rapid and essentially quantitative with small amounts of catalyst. A range of aldehydes and ketones can be reacted successfully, the only exceptions being very bulky ketones. The reaction is very dependent on the efficient removal of water, which leads to faster reaction rates and to much higher conversions. The choice of solvent is also extremely important, with nonpolar solvents such as cyclohexane being optimal. Less polar, higher boiling solvents are significantly less effective, even at much higher reaction temperatures. Catalyst poisoning is slow and appears to be due to amide formation on the surface.Item Michael Additions Catalyzed by N,N-Dimethyl-3-aminopropyl — Derivatized Amorphous Silica and Hexagonal Mesoporous Silica (HMS)(1998-06) Mdoe, James; Clark, James H.; Macquarrie, Duncan J.Solid bases prepared by derivatisation of amorphous silica and hexagonal mesoporous silica with dimethylaminopropyl groups are good catalysts for Michael addition reactions. Of the prepared catalysts, those based on hexagonal mesoporous silica show particularly high activities. The sol-gel method used in preparing the catalysts based on hexagonal mesoporous silica enables loading to be increased to more than twice that of those based on amorphous silica which are prepared by the post-modification method.Item Synthesis and Reactions of Some Derivatives Of (3,6 S,9 R,10 R,11 S)-1,4,7-Trioxaspiro[5,5]Undecane-3,9,10,11-Tetrol: Novel Quasi-Saccharides 1 Presented at the 2nd International Meeting of the Portuguese Carbohydrate Chemistry Group, Porto, Portugal, 21–25 September 1997. 1(1998-10) Regeling, Henk; Sunghwa, Fortunatus; Zwanenburg, Binne; de Gelder, Rene; Chittenden, Gordon J. F.The title compound was obtained by reductive ozonolysis of allyl β-d-fructopyranoside. The synthesis and characterization of a number of C-3-substituted derivatives using conventional carbohydrate procedures is described. Some of the products may be of biological interest as carbohydrate mimics. The structures of two of the basic products (8 and 9) were substantiated by X-ray diffraction studies. Do you want to read the rest of this article?Access full-textItem Heavy Metals in Edible Green Vegetables Grown Along the Sites of the Sinza and Msimbazi Rivers in Dar Es Salaam, Tanzania(Elsevier, 1999) Bahemuka, T. E.; Mubofu, Egid B.Four heavy metals (cadmium, copper, lead and zinc) were determined in some green vegetables cultivated along the sites of the Sinza and Msimbazi rivers. Atomic absorption spectrophotometry was used to estimate and evaluate the levels of these metals in the vegetables. The contributions of the vegetables to the daily intake of the heavy metals from the vegetables were determined. The results showed the following ranges (mg/100 g): 0.01±0.06, 0.25±1.60, 0.19±0.66, and 1.48±4.93 for cadmium, copper, lead and zinc, respectively. Some vegetables contained high levels beyond the permissible levels given by FAO and WHO for human consumption. When the mean levels of cadmium, copper, lead and zinc (0.20, 7.95, 3.95 and 33.75 mg per kg, respectively) were taken into account, the daily intake contribution of these metals was found to be 21.60 mg, 858.60 mg, 426.60 mg and 3.65 mg for cadmium, copper, lead and zinc, respectively.Item Preventing Termite Attack: Environmentally Friendly Chemical Combinations of Cashew Nut Shell Liquid, Sulfited Wattle Tannin and Copper (II) Chloride(1999) Mwalongo, Gerold C. J.; Mkayula, Lupituko L.; Dawson-Andoh, B.; Mubofu, Egid B.; Shields, J.; Mwingira, Bonaventura A.In this study, a combination of three chemicals (cashew nut shell liquid, sulfited wattle tannin and copper(II) chloride) has been used to develop an environmentally friendly termite preservative. Cashew nut shell liquid (CNSL) is a by-product of cashew nut kernel processing factories and its use in the preservative formulations minimises the wastes from the factory as well as the amount of conventional hazardous preservatives from entering the environment. The formulated preservatives were tested for their ability to preserve wood blocks from a soft wood, ponderosa pine (Pinus ponderosa) and a hard wood, trembling aspen (Populus tremuloide). Sulfonated wattle tannins alone or combined with copper chloride at different concentrations, and cashew nut shell liquid (CNSL) without or with copper chloride were used in treating the 14 × 14 × 14 mm wooden blocks from the two wood species. The samples were exposed to termite attack in the surveyed fields in Arusha and Moshi, Tanzania. After 108 days exposure, evaluation of termite attack by measuring the weight losses and damage showed that the test wood treated with the combinations 40% CNSL + 1% CuCl2 and 40% CNSL + 2% CuCl2 were among least damaged.Item Organomodified hexagonal mesoporous silicates(1999-01) Macquarrie, Duncan J.; Jackson, Dominic B.; Mdoe, James; Clark, James H.A neutral templating route to organically modified silicates with tightly controlled porosity is described. The materials prepared are characterised and compared to the corresponding organofunctionalised silica