1,721,037 research outputs found
Toward an evolutionary historiography and epistemology of medicine. The legacy of Mirko Grmek.
No full textMirko Grmek has proved that a naturalistic approach to the history of medicine is possible. In his works he showed that the historical and epistemological research can use different kind of conceptual tools and knowledge, borrowed from history, anthropology and medicine, to understand more deeply the historic development of medical thinking. Moving from Grmek original concept of "pathocenosis" is possible to link his ideas to the evolutionary perspective, present in the contemporary medical thought as "evolutionary medicine" or "Darwinian medicine". The last one sees the disease as an inconsistency between phenotypes and environmental conditions, and a by-product of the necessity to stock variations to respond to the mutability of external conditions. Today, the evolutionary approach to medicine gives us a new way for taking care of the sick. At the same time it supplies a new way to solve the eternal theoretical problem of determining a shared and consistent definition of the disease's concept and medicine status
Review: T. Baldwin; C. Preti (eds): G.E. Moore: Early Philosophical Writings
No full textThis is a review of T. Baldwin; C. Preti (eds): G.E. Moore: Early Philosophical Writings
voce relativa a Grassi Orazio,
No full textla biografia dello studioso savonese, attivo nella prima metà del XVII secol
Investigations on chromium (III), manganese (II), tin (II) and lead (II) dithiocarbamate complexes
No full textPiperidine-, morpholine-4-, N-methylpiperazine-4- and thiornorpholine-4-carbodithioate complexes of chromium(III), manganese(III), tin(II) and lead(II) are prepared and characterized by chemical analyses, spectroscopic methods (I.R. and electronic spectra), magnetic susceptibilities, conductivity measurements and mass spectra. The complexes are of the type M(R2dtc)n, where n is the oxidation number of the metal ion. Where possible a tentative stereochemistry of the complexes is discussed on the basis of the results obtained. In all the complexes the dithiocarbamate ligands show bidentate behaviour
Five-coordinate low-spin cobalt (II) complexes with benzeneseleninato ions and ethylenediamine as ligands
No full textFive-coordinate bis(benzeneseleninato)tris(ethylenediamine) cobalt (II)complexes are obtained by reaction of Co(H2O)2 (XC6 H4 SeO2)2 complexes (X = H, p-Cl, m-CI, p-Br, ni-Br, p-Me,p-NO2) with ethylenediamine. The diaquo complexes (one mole)react with ethylenediamine (three moles)to form O-seleninato derivatives. Spectral and magnetic properties show that the complexes are low-spin (s = 1/2) and,on the basis of the electronic spectra a distorted trigonal geometry,D 3h , is suggested. Assignments for the electronic spectra are proposed. Conductivity data indicate that these derivatives are nonelectrolytes. Both ethylenediamine and [RSeO2 ]– behave as monodentate ligands
Preparation and studies of some antimony and bismuth trisdithiocarbamate and five-coordinate monohalobisdithiocarbamate derivatives
No full textThe complexes of antimony(III) and bismuth(III) with piperidinedithiocarbamate (Pipdtc), morpholinedithiocarbamate (Morphdtc) and thiomorpholinedithiocarbamate (Timdtc) of general formula M(Rdtc)3 have been prepared, and characterized by spectroscopic methods. The data show that the complexes have a distorted octahedral stereochemistry, this distortion being due to the stereochemically active lone-pair of electrons on the antimony and bismuth atoms.A new series of pentacoordinate complexes of general formula M(Rdtc)2X, M being antimony or bismuth, X a halogen and Rdtc the above dithiocarbamates, has been prepared by reacting the corresponding trisdithiocarbamates with chlorine, bromine and iodine. The compounds have been characterized by IR and electronic spectroscopy and molecular weight determinations. The infrared spectra suggest that each dithiocarbamate group coordinates as a bidentate ligand; the metal—halide and metal—sulphur stretching modes have also been assigned. The spectral data are discussed and compared with those of the corresponding trisdithiocarbamate derivatives. The molecular weight determinations indicate that the trisdithiocarbamate complexes are monomeric; for the monohalobisdithiocarbamates, the antimony derivatives are shown to be monomeric, while the bismuth derivatives tend to dimerize
Metal-ligand bonding in benzeneseleninato complexes of p- and d- block metals
No full textNew complexes of lead(II) and zirconium(IV) withmeta-andpara-substituted benzeneseleninic acids are reported and characterized by chemical analyses, spectroscopic methods and conductivity and magnetic measurements. The complexes are of the Pb(XC6H4SeO2)2 and ZrO(XC6H4SeO2)2 type; for zirconium(IV), working with a 1:4 metal:ligand stoichiometrical ratio, invariably the oxy derivative was obtained. The i.r. spectral data suggest that the complexes contain RSeO 2 – ligands acting as bidentate in O,O -seleninato complexes, Where possible, a tentative stereochemistry for the complexes is discussed on the basis of the results obtained
Synthesis and characterization of ruthenium dithiocarbamate complexes
No full textPiperidine carbodithioate (Pipdtc), morpholine-4-(Morphdtc), thiomorpholine-4-(Timdtc), piperazine-4-(Pzdtc) and N-methylpiperazine-4-carbodithioate (CH3-Pzdtc) complexes of ruthenium have been prepared and characterized by spectroscopic methods (IR and electronic spectra), magnetic susceptibilities and conductivity measurements. Where possible a tentative stereochemistry of the complexes is discussed based upon the obtained results. The dithiocarbamate ligands show in all the complexes a bidentate behaviour. A distorted octahedral geometry is proposed for the water containing 1:2 derivatives: in fact from a detailed analysis of the infrared spectra the water resulted always coordinated to the metal. The Pzdtc 1:2 derivative resulted polymeric octahedral with the NH group of the heterocyclic ring involved in the coordination
Osmium carbodithioato derivatives. Syntesis and spectroscopic studies
No full textSeveral new dithiocarbamate complexes of osmium(III) and osmium(II) have been synthetized and characterized by i. r. and electronic spectra, magnetic susceptibilities and conductivity measurements. The dithio ligands show a bidentate behaviour in all the complexes. From the electronic absorption spectra the values of the ligand field parameters were determined; the nephelauxetic parameter is indicative of a strong covalency in the metal-ligand bond as confirmed by the Dq values. All the complexes of osmium (III) and osmium(II) were octahedral, distorted owing to the presence of two molecules of coordinated water the metal(II) derivatives; the room temperature magnetic susceptibility values show that the complexes are of low-spin type: the osmium(III) derivatives have one unpaired electron, while the osmium (II) ones were diamagnetic
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