Showing papers by "University of Palermo published in 1976"
TL;DR: In this article, a non-linear constitutive equation for polymer melts and concentrated solutions is presented, which is based on known results of network theories, and the model contains a distinctive feature: that of letting the relaxation times depend upon the existing structure.
Abstract: A non-linear constitutive equation for polymer melts and concentrated solutions is presented. Based on known results of network theories, the model contains a distinctive feature: that of letting the relaxation times depend upon the existing structure. The model extends the constitutive equation of linear viscoelasticity to the non-linear region in a well-defined way, with the uncertainty of just a single adjustable parameter. Predictions of the model for common cases of non-linear response are derived and discussed.
150 citations
TL;DR: In this paper, a model of nonlinear viscoelasticity with relaxation times which depend on the structure is compared with experimental results reported in the literature for a L.D. polyethylene.
Abstract: A model of non-linear viscoelasticity with relaxation times which depend on the structure is compared with experimental results reported in the literature for a L.D. polyethylene. The single parameter of the model is determined by comparison with steadystate shear results. The model is then used to interpret various transient data. These are: tangential and normal stress growth in shear, stress growth in elongation, normal stresses in shear creep. The comparison shows a good general agreement, thus supporting the suggestion of relating the change in time of the relaxation spectrum to structural variables.
59 citations
TL;DR: The following 14 species of phytoseiid mites were recorded on various plants:Typhlodromus kerkirae sp.
Abstract: Typhlodromus hellenicus sp. nov. is described and illustrated. The following 11 additional species were recorded:T. pyri Scheuten, sensu Abbasova,T. exhilaratus Ragusa,T. recki Wainstein,T. kerkirae Swirski and Ragusa,Amblyseius cinctutus Livshitz and Kuznetsov,A. stipulates Athias-Henriot, A. aff.finlandicus (Oudemans), A. aff.aberrans (Oudemans),A. potentillae (Garman),Phytoseiulus persimilis Athias-Henriot, andPhytoseius (Phytoseius) finitimus Ribaga.
43 citations
TL;DR: In man, absorption of thiotepa was highest after transurethral surgery and was also increased in cases with extensive anaplastic tumours or in the presence of acute inflammatory reactions.
Abstract: The permeability of the bladder mucosa to thiotepa and to the anthraquinonic antibiotics, adriamycin and daunomycin, was investigated both in humans and in experimental animals. Instillations in rabbits were performed either in intact males or in animals with ligated ureters. Absorption of thiotepa was significantly higher than that of the antibiotics both in men and in rabbits. Furthermore a qualitative difference was observed in rabbits in relation to time and with regard to fixation to vesical tissues. In man, absorption was highest after transurethral surgery. It was also increased in cases with extensive anaplastic tumours or in the presence of acute inflammatory reactions.
38 citations
TL;DR: In this paper, the rate of ozone absorption into KOH aqueous solutions has been measured using a packed column, and the results can be interpreted on the basis of a first order reaction in both O 3 and OH −.
31 citations
TL;DR: In this paper, the main peak of the CaSO 4 : Dy phosphors at various temperatures and 60 Co γ doses are described and the decay curves at 100 rad are broken down in exponential terms and for each term the decay constant and the related partial light sum are obtained.
24 citations
TL;DR: In this paper, the conductance of potassium iodide has been measured in the solvents ethylene carbonate, water, methyl ethyl ketone, and pairwise mixtures of these mixtures at 40°C; no correlation between KA and solvent properties could be established.
Abstract: The conductance of potassium iodide has been measured in the solvents ethylene carbonate, water, methyl ethyl ketone, and pairwise mixtures of these solvents at 40°C; and ethylene carbonate-water, tetramethylene sulfone-water, dimethyl sulfoxide-water, tetrahydrofuran-water, ethylene carbonate-tetramethylene sulfone-water, ethylene carbonate-tetramethylene sulfone, and tetrahydrofuran-dimethyl sulfoxide at 25°C. For dielectric constants greater than about 60, the pairing constants KA are in the range 0.3–2.0; no correlation between KA and solvent properties could be established. For lower dielectric constants, KA increases exponentially with decreasing dielectric constant. Addition of a proton, acceptor to water initially decreases KA regardless of whether the dielectric constant of the mixture is higher or lower than that of water, suggesting that ion pairs in water may be stabilized by cage structures. The Walden product Aoη is also decreased by the addition of proton acceptors.
22 citations
20 citations
TL;DR: In this paper, the synthesis of diphenylantimonates (V) of the type M(I) [PH 2 XbX 4 ] (M(I = PH 4 As; X = F, Cl, Br, N 3, NCS; X 4 = Cl 3 Br, Cl 3 N 3 ) are described.
16 citations
TL;DR: Nutritional mutants (co-mutants) were scored among nitrosoguanidine-induced revertants of four mutations in Streptomyces coelicolor A3 and mutations appeared to be completely abolished outside the co-mutation region (mutation restriction).
Abstract: Nutritional mutants (co-mutants) were scored among nitrosoguanidine-induced revertants of four mutations in Streptomyces coelicolor A3 (2). All co-mutations were due to mutations in genes linked to the revertant locus. The co-mutant loci were located in a region of about 20 map units around the revertant locus (co-mutation region). Revertants for different loci showed co-mutation patterns different from each otehr and from that of random nitroso-guanidine-induced forward mutations. Mutations appeared to be completely abolished outside the co-mutation region (mutation restriction).
16 citations
TL;DR: In this paper, the IR and NMR data suggest an octahedral coordination environment for the antimony atom with meridional arrangement of the ONO ligand atoms and a linear CSbC skeleton.
TL;DR: Cell of sea urchin hatching blastulae and gastrulae when reaggregated together do not influence each other with respect to the rate of rRNA synthesis, and synthesis of ppGpp is not detected at any of the investigated developmental stages.
TL;DR: In this article, the infrared absorption at the local mode frequency for various isolated impurities such as B, Al, Mg, Si, C, and P in GaAs is calculated.
TL;DR: In this article, the biaxial extension results by Denson et al. are compared with the predictions of a model of non-linear viscoelasticity, and the date of uniaxially extension on the same material (a commercial polyisobutylene) are taken for extending the comparison.
Abstract: The biaxial extension results byDenson et al. are compared with the predictions of a model of non-linear viscoelasticity. Date of uniaxial extension on the same material (a commercial polyisobutylene) are taken for extending the comparison. The model used seems to adequately describe both types of elongational flow with the same value of the single adjustable parameter.
TL;DR: In this paper, a plaque assay was made to characterize two variants of the Edmonston strain of the measles virus and to obtain plaque purified virus populations, and the results showed that plaque purified viruses are more likely to survive than those without plaque.
Abstract: Attempts were made to characterize by a plaque assay two variants of the Edmonston strain of measles virus and to obtain plaque purified virus populations.
TL;DR: Findings indicate that in dystrophic rat retinol content increases, whereas the amount of retinyl esters is always lower than normal.
Abstract: A comparative study of the retinol and retinyl ester concentrations was performed in the retinal pigment epithelium of the normal and affected rats. Our findings indicate that in dystrophic rat retinol content increases, whereas the amount of retinyl esters is always lower than normal. An hypothesis can be made on the deficiency of enzymic activities which regulate retinol retinol and retinyl esters levels in the pigment epithelium.
TL;DR: It is suggested that oocytes synthesize proteins at the same rate as unfertilized eggs, both in vivo and after oocyte and egg isolation.
TL;DR: In this article, real-time holographic interferometry is applied to determine the absolute retardation fringes in the photoelastic analysis of plane models, which requires only one hologram recorded with the model unloaded.
Abstract: In this paper, real-time holographic interferometry is applied to determine the absolute-retardation fringes in the photoelastic analysis of plane models. The method requires only one hologram recorded with the model unloaded. In the reconstruction process, the mcdel is loaded and the polarizers on the reference and object beams are rotated through the same angle. At the points of the model where the polarization direction is parallel to one of the principal stresses, only the corresponding family of absolute retardations is obtained. The technique is demonstrated experimentally using a deep beam centrally loaded.
TL;DR: The Piancaldoli meteorite was found on the roof of a house in Florence, Italy in 1968 as mentioned in this paper, and the trajectory and the terminal point were calculated, leading to the recovery of three small meteoritic fragments.
Abstract: The fall occurred near Piancaldoli, Florence, Italy, at 19.14 U.T. on the 10th August 1968. The fireball broke up in the atmosphere producing a cloud like a balloon.
The trajectory and the terminal point were calculated, leading to the recovery of three small meteoritic fragments, found on the roof of a house. Chemical analysis gave the following results: SiO2 40.80; TiO2 0.15; Al2O3 2. 70; Cr2O3 0.47; FeO 17.20; MnO 0.07; MgO 25.18; CaO 1.95; Na2O 0.64; K2O 0.07; P2O5 0.20; NiS 0.93; FeS 6.24; Fe° 2.40; Ni° 0.40; Co 0.05; sum 99.45.
In the lithic portion of the meteorite the following minerals were found: both clino and orthopyroxenes (En = 76 to 98%), olivines (Fo = 66 to 98%), troilite, pyrrhotite, pentlandite, kamacite, ilmenite, apatite, merillite, schreibersite, chromite and Henderson phase.
From all the mineralogical and petrological data, we conclude that the Piancaldoli meteorite is an “unequilibrated ordinary chondrite,” LL3. The microbrecciated structure of the rock and some shock features were observed, while the rock as a whole is unshocked, suggesting that these features were caused by impact events which took place during the accretion of the parent body.
TL;DR: Variations of PRA and plasma aldosterone levels were only slight when plasma volume was made to increase due to administration of polyvinylpirrolidone solution, and PRA was significantly lower in rats having received saline salution.
TL;DR: An investigation was made of the effect of thermic stress on the somatic rage reaction and on rapid circling turns in cats awake and free to move in a behavioural cage, indicating an increase in their excitability corresponding to a increase in spontaneous and evoked somatic motor activity.
Abstract: (5 figures)An investigation was made of the effect of thermic stress on the somatic rage reaction and on rapid circling turns in cats awake and free to move in a behavioural cage.An increase in room temperature had a two-phase effect on the excitability of the nervous structures stimulated that is able to evoke the somatic rage reaction and rapid circling turns. The first phase, at room temperature 25d`-30d`C, was characterized by hypoexcitability; the second phase, appearing after longer periods of exposure and at temperatures above 30 d`C, was characterized by the onset panting, hyperexcitability of the nervous structures stimulated and then by lowering of the somatic rage reaction threshold and a very significant increase in the number of circling turns.Experimentation on the action of cold external temperature on the excitability of structures involved in evoking the somatic rage reaction and rapid circling turns indicated an increase in their excitability, corresponding to an increase in spon...
01 Oct 1976
TL;DR: In this paper, a new method of biological sample characterization at millimeter waves has been studied to verify and extend Webb's experimental results, based on interferometric measurements, is suitable to obtain an absorption spectrum of a living bacterial sediment with a high sensitivity.
Abstract: A new method of biological sample characterization at millimeter waves has been studied to verify and extend Webb's experimental results. This method, based on interferometric measurements, is suitable to obtain an absorption spectrum of a living bacterial sediment with a high sensitivity. It has been applied in the frequency range 66-73 GHz. Some experimental results are reported.
01 Sep 1976
TL;DR: It is suggested that inhibition of RNA polyadenylylation in sea urchin mesenchyme blastulae causes a disturbance of the transport of all the size classes of newly synthesized RNA from the nucleus to the cytoplasm.
Abstract: It is suggested that inhibition of RNA polyadenylylation in sea urchin mesenchyme blastulae causes a disturbance of the transport of all the size classes of newly synthesized RNA from the nucleus to the cytoplasm.
TL;DR: The transport of metabolites to and from the central nervous system is of considerable interest and presumably the transport systems responsible for this uptake and for efflux invitro are also those responsible for transport between brain cells in living animals2.
Abstract: The transport of metabolites to and from the central nervous system is of considerable interest. To a greater extent than most other tissues, central nervous system tissue invitro takes up amino acids to well above their concentrations in the incubation medium. Presumably the transport systems responsible for this uptake and for efflux invitro are also those responsible for transport between brain cells in living animals2.
TL;DR: The suggestion is made that mitRNA synthesis is under nuclear control through the synthesis of some protein coded for by the nuclear genome.
TL;DR: In this article, the structure of the complex ions has been inferred from Laser-Raman and infrared spectra in the solid state and 1H NMR in solution, consistent with a facial configuration of the organometallic moiety.
Abstract: The novel ionic complexes [(C6H5)4As]2 [(CH3)3PtX3](X = Cl− and Br−) and [(CH3)3Pt(bipy)L]+[B(C6H5)4]− (bipy = 2,2′-bipyridine, L = aliphatic and aromatic isocyanide) have been prepared. The structure of the complex ions has been inferred from Laser-Raman and infrared spectra in the solid state and 1H NMR in solution. These data are consistent with a facial configuration of the organometallic moiety. Trends in vibrational frequencies ν(Pt-C) and ν(Pt-X) indicate a “trans” influence sequence for the ligands, which in the case of (CH3)3PtX2- 3 is related with that found for (CH3)2AuX− 2 ions.
TL;DR: In this paper, the second-order solution of a negative resistance oscillator whose active device has a piece-wise analytical characteristic is presented, and the frequency and the harmonic content of the oscillation waveform are obtained as functions of the circuit parameters and of the device bias.
Abstract: The second-order approximated solution of a negative resistance oscillator whose active device has a piece-wise analytical characteristic is presented. The frequency and the harmonic content of the oscillation waveform are obtained as functions of the circuit parameters and of the device bias.
TL;DR: In this article, the origin of the overlap charges in AgCl and their effects on the lattice dynamics are discussed, and the dispersion curves for various positions of overlap charges and the physical meaning of the values of the parameters is discussed.