16 research outputs found
Adiabatic invariants and Mixmaster catastrophes
We present a rigorous analysis of the role and uses of the adiabatic
invariant in the Mixmaster dynamical system. We propose a new invariant for the
global dynamics which in some respects has an improved behaviour over the
commonly used one. We illustrate its behaviour in a number of numerical
results. We also present a new formulation of the dynamics via Catastrophe
Theory. We find that the change from one era to the next corresponds to a fold
catastrophe, during the Kasner shifts the potential is an Implicit Function
Form whereas, as the anisotropy dissipates, the Mixmaster potential must become
a Morse 0--saddle. We compare and contrast our results to many known works on
the Mixmaster problem and indicate how extensions could be achieved. Further
exploitation of this formulation may lead to a clearer understanding of the
global Mixmaster dynamics.Comment: 24 pages, LaTeX, 5 figures (which can be obtained by sending a
message to the first author), submitted to Phys.Rev.
Does Very early Initation of HAART in Patients on TB Treatment Provide Benefit in a High Income Setting?
info:eu-repo/semantics/nonPublishe
Complementary Study of Cytotoxic Activity of Melinonine F.
The cellular effects of melinonine F, an alkaloid isolated from STRYCHNOS MELINONIANA (South America) and STRYCHNOS USAMBARENSIS (Central Africa), are analysed in cancer or normal cells in culture. A cytotoxic action is noted in both types of cells, at least for relatively high concentrations. These effects are probably due to interaction of the drug with chromatin. Physico-chemical analysis demonstrates partial intercalation of melinonine F on pure DNA IN VITRO
Effects of Three Alkaloids Isolated from Strychnos Usambarensis on Cancer Cells in Culture.
The cellular effects of three alkaloids isolated from STRYCHNOS USAMBARENSIS (melinonine F, strychnofoline, 18-19-dihydro-usambarine) are analysed by cytological methods in experimental animal tumours cultivated IN VITRO (B 16 mouse melanoma cells, mouse Ehrlich tumour cells ELT, HW 165 rat hepatoma). Under some experimental conditions, a certain degree of antimitotic activity is demonstrated
Hooping cough in adults, think about it!
We report the case of a 47 year old patient who had been suffering from persistent cough for more than three weeks. Patient coughed predominantly during night time, without fever. The amoxicillin-clavulanic acid initially prescribed was not effective. A series of complementary investigations were performed before serology finally identified Bordetella pertussis infection after two months of symptoms which improved slowly without evident benefit of macrolide treatment. The diagnosis of whooping cough was also established for the wife of the patient with fast resolution of the symptoms after rapid unset of treatment with macrolides</p
In Vitro Activities of Strychnos Alkaloids and Extracts against Plasmodium falciparum
The in vitro antimalarial activities of 46 alkaloids and extracts from Strychnos species were evaluated. Two types of quasidimeric alkaloids exhibit high and selective activities against Plasmodium. Strychnopentamine and isostrychnopentamine were active against chloroquine-sensitive and -resistant strains (50% inhibitory concentration [IC(50)] ≈ 0.15 μM), while dihydrousambarensine exhibited a 30-fold higher activity against the chloroquine-resistant strain (IC(50) = 0.03 μM) than it did against the chloroquine-sensitive strain