Benjamin F. Gherman, Stephen J. Lippard, Richard A. Friesner,
... CH3, OH, CN, NO2) substrate hydroxylation in MMOH (Ambundo, E. A.; Friesner, R. A.; Lippard, S. J. ...
Tópico(s): Petroleum Processing and Analysis
2004 - American Chemical Society | Journal of the American Chemical Society
M. Mylrajan, E.A. Ambundo, Simon J. George, Stephen J. Lippard, R. N. F. Thorneley,
The hydroxylase component (MMOH) of soluble methane monooxygenase from Methylococcus capsulatus (Bath) was reduced to the diiron(II) form and then allowed to react with dioxygen to generate the diiron(IV) intermediate Q in the first phase of a double-mixing stopped-flow experiment. CD3NO2 was then introduced in the second phase of the experiment, which was carried out in D2O at 25 °C. The kinetics of the reaction of the substrate with Q were monitored by stopped-flow Fourier transform infrared spectroscopy, ...
Tópico(s): Hemoglobin structure and function
2003 - American Chemical Society | Journal of the American Chemical Society
E.A. Ambundo, Qiuyue Yu, L. A. Ochrymowycz, D. B. Rorabacher,
The electron-transfer kinetics for each of three copper(II/I) tripodal ligand complexes reacting with multiple reducing and oxidizing counter reagents have been examined in aqueous solution at 25 degrees C, mu = 0.10 M. For all of the ligands studied, an amine nitrogen serves as the bridgehead atom. Two of the ligands (PMMEA and PEMEA) contain two thioether sulfurs and one pyridyl nitrogen as donor atoms on the appended legs while the third ligand (BPEMEA) has two pyridyl nitrogens and one thioether ...
Tópico(s): Metal-Catalyzed Oxygenation Mechanisms
2003 - American Chemical Society | Inorganic Chemistry
E.A. Ambundo, Richard A. Friesner, Stephen J. Lippard,
The reactivity of intermediate Q of soluble methane monooxygenase from Methylococcus capsulatus (Bath) with a series of derivatized methanes of general formula CH3−R, where R = CN, NO2, and OH, and their deuterated analogues is described. Despite relatively slow reactions, significant kinetic isotope effects, KIEs, are observed in reactions with acetonitrile and nitromethane; however, none is obtained with methanol. In addition, evidence of a substrate-binding step that occurs prior to substrate oxidation ...
Tópico(s): Metalloenzymes and iron-sulfur proteins
2002 - American Chemical Society | Journal of the American Chemical Society
E.A. Ambundo, L. A. Ochrymowycz, D. B. Rorabacher,
The tripodal ligand TMMEA (tris(2-methylthioethyl)amine) forms a trigonal bipyramidal complex with copper(II) in which the bridgehead nitrogen occupies one axial site, a solvent molecule (or anion) occupies the opposite axial site, and the three thioether sulfurs occupy the three planar sites. Upon reduction to copper(I), the axial solvent molecule (or anion) dissociates to leave a trigonal pyramidal complex with shortened Cu-S bonds and an elongated Cu-N bond. Therefore, both oxidation states maintain ...
Tópico(s): Magnetism in coordination complexes
2001 - American Chemical Society | Inorganic Chemistry
Qiuyue Yu, C.A. Salhi, E.A. Ambundo, Mary Jane Heeg, L. A. Ochrymowycz, D. B. Rorabacher,
The absolute magnitude of an "entatic" (constrained) state effect has never been quantitatively demonstrated. In the current study, we have examined the electron-transfer kinetics for five closely related copper(II/I) complexes formed with all possible diastereomers of [14]aneS(4) (1,4,8,11-tetrathiacyclotetradecane) in which both ethylene bridges have been replaced by cis- or trans-1,2-cyclohexane. The crystal structures of all five Cu(II) complexes and a representative Cu(I) complex have been established ...
Tópico(s): Free Radicals and Antioxidants
2001 - American Chemical Society | Journal of the American Chemical Society
E.A. Ambundo, M.-V. Deydier, L. A. Ochrymowycz, D. B. Rorabacher,
The complex formation kinetics of aquated copper(II) ion reacting with 12 related tripodal ligands have been studied in aqueous solution at 25 degrees C, mu = 0.10 M (NaClO4). For most of the ligands studied, specific formation rate constants have been resolved for both the unprotonated and monoprotonated ligand species. All of the tripodal ligands included in this study contain a bridgehead amine nitrogen with the three legs consisting of 2-methylthioethyl or 2-ethylthioethyl and/or 2-pyridylethyl ...
Tópico(s): Electrochemical Analysis and Applications
2000 - American Chemical Society | Inorganic Chemistry
E.A. Ambundo, M.-V. Deydier, Andrew J. Grall, N. Aguera-Vega, L.T. Dressel, Thomas H. Cooper, Mary Jane Heeg, L. A. Ochrymowycz, D. B. Rorabacher,
Twelve related tripodal ligands have been synthesized in which the three legs linked to a bridgehead nitrogen are 2-methyl- or 2-ethylthioethyl and/or 2-pyridylethyl or -methyl. Utilization of both terminal methyl and ethyl groups on the thiaether legs was designed to determine whether slight differences in solvation or steric effects might cause detectable changes in properties. Inclusion of both methyl and ethyl linkages of the pyridines to the bridgehead nitrogen provides a comparison of the effect ...
Tópico(s): Lanthanide and Transition Metal Complexes
1999 - American Chemical Society | Inorganic Chemistry
Tópico(s): History of Colonial Brazil
1998 - Boston University | The International Journal of African Historical Studies
Mercy Jepkorir, Tobias Ambundo, Chrispus Ngule, Jecinta Ndung’u, Douglas Njuguna, Regina Mbugua, Jean Chepng’etich, Peter Mwitari,
Tópico(s): Agricultural Practices and Plant Genetics
2018 - Sciencedomain International | Journal of Complementary and Alternative Medical Research
O Reino do Congo, Os Mbundu (ou Ambundos), O Reino dos ‘Ngola’ (ou de Angola) e a presença portuguesa, de finais do século XV a meados do século XVI. By Ilídio ...
Tópico(s): African history and culture studies
1997 - Cambridge University Press | The Journal of African History
Produção Nacional
Revisado por pares
... universo cultural dos imbangalas (jagas) e das populações ambundos e kimbundos, que viviam nas regiões portuguesas de ...
Tópico(s): History of Colonial Brazil
2023 - Fundação Oswaldo Cruz, Casa de Oswaldo Cruz | História Ciências Saúde-Manguinhos
Produção Nacional
Revisado por pares
... haviam sido previamente submetidos a ritos divinatório-judiciários ambundos denominados “juramentos do bulungo” para apurar suas culpas. ...
Tópico(s): History of Colonial Brazil
2022 - UNIVERSIDADE ESTADUAL DE GOIÁS | Revista de História da UEG
... texto que agradara aos historiadores e, provavelmente, aos ambundos actuais, pois mostra-nos que os seus antepassados — ...
Tópico(s): History of Colonial Brazil
2007 - Instituto de Ciências Sociais da Universidade de Lisboa | Análise Social
Ambundo Jesse, Zablon Isaboke, Oonge Patts, Meshack Odira,
Groundwater is increasingly an important source of water. Assessment of its variability spatially and temporally besides quality and quantity is not easy. Groundwater contains multiple range of chemical parameters. This contribution proposes a water quality index (WQI) to synthesize various groundwater quality parameters (Na + , F - , Cl ‑ , SO 4 2- , Ca 2+ , Mg 2+ , K + and NO 3 - ) in Geographic Information Systems (GIS) based environment. The parameters are analyzed relative to the Kenya Standard (KS) East Africa Standard ( ...
Tópico(s): Groundwater and Isotope Geochemistry
2022 - Bilingual Publishing | Journal of environment and earth science
JO Nyamuni, E. D. Kokwaro, J H Ouma, TV Ambundo,
Objective : To investigate malaria infection in relation to age and residential area. Design : A cross sectional study. Setting : Kipsamoite Dispensary of Nandi County in Kenya. Subjects : The demographic details and medical history for all consenting patients was taken by the clinical officer/nurse. Intervention : Clinical examination was done followed by presumptive diagnosis for clinical malaria. Main outcomes : A total of 349 patients were examined and tested for malaria during the period under study. Results : ...
Tópico(s): Malaria Research and Control
2015 - African Journals OnLine | East African Medical Journal