Showing papers by "University of Florence published in 1974"
TL;DR: In this article, the interaction of oxygen with the (111) surface of a single crystal is studied, mainly in the pressure range from 10 −3 up to 1 torr and at temperatures from room up to 500°C.
168 citations
TL;DR: A sulphated glycosaminoglycan component (tentatively identified as heparan sulphate) is removed from the transformed cells in a significantly lower relative amount as compared with the control untransformed cells.
60 citations
TL;DR: In this article, the influence of thermophysical property variations on the resulting temperature fields is investigated with reference to quasilinear heat-conduction problems, and it is shown that errors in the calculation of temperature distributions, brought about by an inaccurate estimate of thermal properties, are small if approximate heat capacities, even exhibiting large local differences with respect to the actual ones in a small range of temperatures, retain enthalpy variations and if the integral across the whole working temperature interval of the absolute value of the difference between approximate and actual thermal conductivities is small.
55 citations
TL;DR: In this article, the authors construct the vertices which describe the emission of closed string particles (pomerons) out of open string states (reggeons) and construct a ghost-free unified dual model for the amplitude of an arbitrary number of reggeons and pomerons which contains both the conventional Veneziano model and the Shapiro- Virasoro model.
50 citations
TL;DR: In this article, a theoretical expression for the rate constant of an electrode process as a function of the charge density qi of specifically adsorbed electroinactive ions, derived by Guidelli and Foresti1, is modified taking discreteness-of-charge effects into account, for the particular case in which the activated complex is specifically adorbed, and compared with analogous theoretical expressions derived by Parsons4 and by Fawcett and Levine5, so as to point out both the analogies and the main distinguishing features.
45 citations
TL;DR: From the five-coordinate iron(II) complexes [FeXL] BPh 4, (L = tris(2-diphenylphosphinoethyl)amine, np 3, and tris (2-diplophosphine, pp 3 ) hydrido and hydridor dinitrogen complexes have been obtained; these have formula [FeH(pp 3 )]BPh 4 and [FeN 2 L]Bph 4 (L= np 3, PP 3, PP 3 ) as discussed by the authors.
45 citations
01 Apr 1974
31 citations
TL;DR: In this paper, the potential energy surfaces of alkali halides have been computed taking into account the spin-orbit interaction and the linear and quadratic Jahn-Teller interactions with vibrational modes.
Abstract: The $^{3}T_{1\ensuremath{\mu}}$ and $^{3}A_{1\ensuremath{\mu}}$ adiabatic potential energy surfaces of ${\mathrm{T}1}^{+}$-type impurities in alkali halides have been computed taking into account the spin-orbit interaction and the linear and quadratic Jahn-Teller interactions with ${E}_{g}$ vibrational modes. Effects of ${T}_{2g}$ modes are assumed to be negligible. The inclusion of the quadratic effect leads to tetragonal nondegenerate $T$ minima with underlying trap levels, besides $X$ minima and their trap level already predicted for the linear Jahn-Teller effect. This level scheme is required in order to explain many experimental features concerning ${A}_{T}$ and ${A}_{X}$ emissions.
28 citations
TL;DR: In this paper, the reduction rate kf of BrO4− in the presence of halides and pseudohalides at sufficiently negative potential with respect to the point of zero charge satisfies the well-known Butler-Volmer equation corrected for diffuse-layer effects according to Frumkin.
28 citations
TL;DR: In this article, the infrared spectra of oriented and random crystalline films of CH 3 CN and CD 3 CN have been studied and the results of the polarization and intensity measurements have allowed to determinate the factor group and the angle of tilt of the molecules.
25 citations
TL;DR: A radioimmunoassay for the determination of testosterone in human plasma is described and the reliability criteria of the method in terms of precision, accuracy, sensitivity and specificity have been evaluated.
Abstract: SUMMARY
A radioimmunoassay for the determination of testosterone in human plasma is described. After extraction from plasma, testosterone is separated by paper chromatography. The radioimmunoassay is performed using an antiserum to testosterone-3-oxime-rabbit serum albumin and a saturated solution of ammonium sulphate is used for separation. The reliability criteria of the method in terms of precision, accuracy, sensitivity and specificity have been evaluated.
The mean level of testosterone in plasma samples from nineteen normal men (age range 16–73 years) is 527±226 (±SD) ng/100 ml. In ten normal ambulatory females (in the second phase of the cycle) aged 19–35 years the mean plasma testosterone is 27±8±10±6 (±SD) ng/100 ml. In twenty-four impotent men (aged 18–50) the testosterone level is 431±191 (mean±SD) ng/100 ml. These values are not significantly different from normal subjects.
Lastly, the testosterone levels found in a few cases of male hypogonadism are reported.
TL;DR: In this article, an e.s.r. study of Copper(II) complexes with the following linear aliphatic polyamines: ethylenediamine, 1,3-diaminopropane, triethylenetetramine, 3,3′-diminopropylamine and N,N,N′, N′,N″,N'',N
TL;DR: Results do not support the hypothesis that a link between the effect of morphine on nociception and brain ACh exists, and instead suggest that brain and spinal ACh levels were only increased by morphine when the dose of the drug did not produce remarkable behavioural excitation.
TL;DR: The combined treatment with PCPA and testosterone significantly increases the sexual activity more than PCPA, testosterone and placebo, when given on their own, whereas subjects with normal sexual efficiency on chronic treatment with tryptophan reported a decrease of sexual tone.
01 Sep 1974
TL;DR: In this article, the crystal structure of alunogen was determined by means of photographic X-ray data collected from a twinned crystal, and the dominant structural feature is the three-dimensional hydrogen bonding system which connects the discrete Al(H2O)6 octahedra with the SO4 tetrahedra (two and three respectively in the asymmetric unit).
Abstract: The crystal structure of alunogen, space group\(P\bar 1\),a=7.425(2),b=26.975(2),c=6.0608(5) A, α=90.03(1), β=97.66(2), γ=91.94(1)°, was determined by means of photographic X-ray data collected from a twinned crystal. The structure was solved by direct methods and refined by least-squares to anR index of 0.064. The dominant structural feature is the three-dimensional hydrogen bonding system which connects the discrete Al(H2O)6 octahedra with the SO4 tetrahedra (two and three respectively in the asymmetric unit). As to the water molecules, twelve behave as ligands coordinated to the Al atoms; four lie in a channel running parallel to thec axis; a fifth one with partial occupancy also lies in the channel and forms still weaker bonds. The crystal chemical formula of the investigated sample is therefore [Al(H2O)6]2(SO4)3·4.4H2O. An explanation of twinning, with (010) as the twin plane, is given.
Journal Article•
TL;DR: In this article, the infrared and Raman spectra of 2,2′-bifurane in the liquid and solid state have been measured between 4000 and 50 cm −1.
TL;DR: The experiments show that each type of convulsant affected spinal ACh stores in a different way, and following prolonged seizures the ACh concentration was not affected.
TL;DR: In this article, preliminary researches have been carried out on the algal flora of Sar Uanle, lying south of Chisimaio in southern Somalia, and the material first collected for these researches, that includes 69 species, appears mainly new for the Somalia coasts.
Abstract: Contribution to the study of the marine algae of Sar Uanle (Southern Somalia). – Some preliminary researches have been carried out on the algal flora of Sar Uanle, lying south of Chisimaio in southern Somalia. The material first collected for these researches, that includes 69 species, appears mainly new for the Somalia coasts. This is due to the fact that the bibliography concerning this part of the western Indian ocean is very scarce. The presence of a remarkable percentage of species that are widely distributed in the indo-malaysian area, has been found out through the results of these enquiries.
TL;DR: In this article, the electrochemical oxidation of o - and m -toluidine has been investigated at platinum and carbon paste electrodes with periodical renewal of the diffusion layer and with the cyclic voltammetry in the pH range 0.7-12.5.
TL;DR: Findings on the in uiuo AChE activity of tI,x frog spinal cord after convulsions had been elicited by the administration of leptazol, strychnine and bicuculline are reported.
Abstract: THE PRECISE mechanism of action of bicuculline and leptazol is not fully understood. Conflicting data exist on the specificity of bicuculline as a y-aminobutyric acid antagonist (CURTIS et al., 1971b; GODFRAIND et al., 1970; STRAUGHAN et al., 1971) and the suggestion has been made that some effects of bicuculline in oiuo could be related to the inhibition of AChE (acetylcholine acetylhydrolase; EC 3.1.1.7.) activity in the CNS (SVENNEBY & ROBERTS, 1973). Leptazol has been claimed as possessing some inhibitory properties' on AChE (MAHON & BRINK, 1970) that might explain part of its convulsant effect which is probably due to the shortening of the time required for synaptic recovery (ESPLIN & ZABLOCKA-ESPLIN, 1969). Strychnine is known to block glycine-mediated postsynaptic inhibition (CURTIS et al., 1971a) but also to inhibit AChE in the frog brain (TORDA & WOLFF, 1947). However all these studies on AChE were carried out in uitro. We report here some findings on the in uiuo AChE activity of tI,x frog spinal cord after convulsions had been elicited by the administration of leptazol, strychnine and bicuculline. All these drugs are able to modify the spinal ACh levels in this species (NISTRI & PEPEU, 1972, 1974) but no inhibitory effect on AChE was found.
TL;DR: The actions of histamine on heart rate and contractility are substantially unaffected by antiadrenergic drugs, by compounds interfering with the storage and release of catecholamines, and by classical antihistamines.
Abstract: The actions of histamine on heart rate and contractility are substantially unaffected by antiadrenergic drugs, by compounds interfering with the storage and release of catecholamines, and by classical antihistamines [1]. Only the histamine-H2 receptor antagonists have been found capable of competitively blocking the positive chronotropic effect of histamine on the guineapig atria [2]. With the aim of better defining the receptors mediating the positive inotropic effect of histamine, experiments were carried out to analise the pattern of the mechanical responses elicited in ventricular muscle by histamine, and to measure the antagonistic action of burimamide and metiamide. These responses were compared with the effects of noradrenaline in order to evaluate the difference in the mechanical responses elicited in ventricular muscle by catecholamines and by histamine.
01 Apr 1974
TL;DR: In this paper, it is argued that the birth of scientific thought and its separation from philosophy is placed within the sixteenth to eighteenth centuries, within that period of time that goes from Bacon to Galileo, and finally to Newton.
Abstract: Y HI LOSOPHY DOES NOT necessarily imply a philosophic method. Nor, as a matter of fact, does a codified philosophic method exist. At best, one could say that philosophy implies accurate reasoning, i.e., logic. Yet, logic is not to philosophy what the scientific method is to science. It would be risky to maintain that there is no philosophy without logic; and, surely, many illustrious philosophers have amply departed from the only logic that philosophic tradition has codified, namely, Aristotelian logic. On the contrary, there is no science, properly speaking, with a scientific method. Scientific method is not unalterable; it is one, but also many, and in continuous evolution. This does not prevent science from presupposing a scientific method. It is by virtue of this criterion, in fact, that the birth of scientific thought and its separation from philosophic thought is placed within the sixteenth to eighteenth centuries, within that period of time that goes from Bacon to Galileo, and finally to Newton.' Does the scientific spirit of the seventeenth century constitute a necessary point of reference for a history of the human sciences as well?
TL;DR: In this article, the electrochemical oxidation of p -toluidine was investigated at platinum and carbon paste electrodes with periodic renewal of the diffusion layer, and with cyclic voltammetry in the pH range 0.7-12.5.
TL;DR: The use of polystyrene-based anion exchangers with aqueous eluents for the separation of primary aromatic amines has been investigated, and extended with satisfactory results to microcrystalline cellulose, cellulose based anion-exchangers and sodium CM-cellulose layers as mentioned in this paper.
TL;DR: The infrared spectra of crystalline thiophene have been investigated in this article, and conditions for obtaining them are described and the structures of the two phases registered at 77 K are discussed.
TL;DR: Polarized spectra of the title compound were recorded and the assignment of the most relevant bands is discussed in this article, with particular attention paid to the B u type band at 1680 cm −1 which is not accounted for in the factor group analysis.
TL;DR: In this article, the infrared spectra in polarized radiation and the Raman spectra of crystalline N 2 H 5 Cl and N 2 D 5 Cl have been measured at −196°C.
TL;DR: Histamine was more effective than noradrenaline in producing a positive inotropic action: the maximum increase in the contractile force was reached by histamine at smaller concentrations than nordrenaline.
Abstract: The pattern of the mechanical responses elicited in guinea-pig ventricular muscle by histamine was analized and compared with the effect of noradrenaline on the same preparation.