Showing papers by "University of Naples Federico II published in 1984"
TL;DR: Delbosco et al. as discussed by the authors established fixed point theorems for selfmaps of complete metric spaces by altering the distances between the points with properties: the use of a function (0 : R -*• R satisfying the following1. cp is continuous and strictly increasing in R ;2. ip(t) = 0 if and only if t = 0 ;3.
Abstract: Let R be the set of nonnegative real numbers and N the set ofpositive integers.Delbosco [/] and Skof [&] have established fixed point theorems forselfmaps of complete metric spaces by altering the distances between thepoints withproperties: the use of a function (0 : R -*• R satisfying the following1. cp is continuous and strictly increasing in R ;2. ip(t) = 0 if and only if t = 0 ;3.
670 citations
TL;DR: In this paper, a generalized least squares estimator of the O-D matrix is proposed combining direct or model estimators with traffic counts via an assignment model, where the presence of measurement errors and time variability in the observed flows is explicitly considered.
Abstract: Methods commonly used for estimating origin-destination (O-D) matrices can be divided into three categories: direct sample estimation, model estimation and estimation from traffic counts. In this paper a generalized least squares estimator of the O-D matrix is proposed combining direct or model estimators with traffic counts via an assignment model. The presence of measurement errors and time variability in the observed flows is explicitly considered. A special case is also presented in which the flows are assumed to be deterministically known. For the proposed estimators, means and dispersion matrices are expressed in function of the possible bias in the direct or model estimators and assignment model misspecification. The variance of the O-D matrix obtained with the generalized least squares (GLS) estimators is proved to be lower than that obtained with direct or model estimators but, because of possible biases and misspecifications, it is suggested that their performances have to be compared by using risk or generalized mean square error criteria.
509 citations
01 Jan 1984
TL;DR: Crystal structures of over three dozen Aib-containing peptides, ranging in length from 2 to 11 residues, have been reported so far which exemplify various types of beta-turns, consecutive beta- turns, and helical structures.
Abstract: The introduction of alpha-aminoisobutyric acid (Aib) into peptides dramatically limits the range of accessible backbone conformations. The presence of two geminal methyl groups at C alpha sterically compels Aib residues to largely favor structures in the right- or left-handed 3(10)/alpha-helical regions (phi approximately +/- 60 +/- 20 degrees, psi approximately +/- 30 +/- 20 degrees) of the peptide conformational map. Aib residues occur extensively in microbial peptides which form transmembrane channels. This observation has stimulated considerable interest in the stereochemistry of Aib peptides. This review summarizes theoretical studies on the conformations of Aib residues and examines the available data on solid-state structures, derived from single crystal X-ray diffraction studies. Crystal structures of over three dozen Aib-containing peptides, ranging in length from 2 to 11 residues, have been reported so far which exemplify various types of beta-turns, consecutive beta-turns, and helical structures. Examples of nonhydrogen bonded and cyclic structures are also described. The crystallographic results compare well with structural studies in solution, establishing that Aib peptides can provide rigid structural models for the development of spectroscopic methods of peptide conformational analysis.
302 citations
TL;DR: In this paper, a continuous uplift at Phlegraean fields, an active volcanic area in southern Italy, that persisted up to September 1984 is described, which was characterized by variable velocity and occurred within an area that extended about 7 km outward from the town of Pozzuoli.
Abstract: During the summer of 1982 a continuous uplift began at Phlegraean Fields, an active volcanic area in southern Italy (Fig. 1), that persisted up to September 1984. The uplift, which reached a maximum value of about 160 cm in the central part of the Phlegraean caldera, was characterized by variable velocity and occurred within an area that extended about 7 km outward from the town of Pozzuoli (Fig. 1); the surface deformation performs a bell-shape pattern. The uplift was accompanied by horizontal displacements and gravity changes that closely correlate with the described elevation changes. The horizontal displacements displayed an anomalous pattern within a narrow belt about 1 km from the center of the uplift and approximately coincident with the area of maximum seismic activity. The change in gravity is attributed primarily to a free-air effect to which a small Bouguer effect must be added. Several models have been invoked in order to explain the observed phenomenon. The one which gives the best fit to the observed data is an increasing pressure source of radial simmetry, at a constant depth of about 3 km beneath the town of Pozzuoli, and having a diameter of several hundred meters. Migration of magma at depth is believed to be responsible for the observed activity in the Phlegraean Fields caldera.
262 citations
TL;DR: The essential features of the ongoing potential pre-eruptive crisis at the Phlegraean Fields begun in August 1982 are summarized and the main problems faced by scientists responsible of volcanic hazards evaluation in such a densely populated area are discussed.
Abstract: The essential features of the ongoing potential pre-eruptive crisis at the Phlegraean Fields begun in August 1982 are summarized and the main problems faced by scientists responsible of volcanic hazards evaluation in such a densely populated area are discussed.
214 citations
TL;DR: In this paper, a model reference adaptive controller is designed using the theory of variable structure systems, where state variable filters are used in order to obtain differentiator-free controllers, and the proposed design allows the error transient to be prescribed in advance.
Abstract: Model reference adaptive controllers, when only input and output measurements are available, are designed using the theory of variable structure systems. State variable filters are used in order to obtain differentiator-free controllers. The proposed design allows the error transient to be prescribed in advance. The drawbacks deriving from the typical high-frequency chattering of the control signal during the sliding motion can be partially eliminated by means of a little modification of the adaptation law that does not cause the error signal to deteriorate considerably.
165 citations
TL;DR: The observation that nontoxic concentrations of the drug are able to induce the in vitro differentiation of both monoblastic and myeloblasticLeukemic cells into mature elements may encourage the exploitation of the differentiating properties of 5-aza- 2′-deoxycytidine in chemotherapy protocols for acute non-lymphoblastic leukemias.
160 citations
TL;DR: In this paper, a robust control technique is developed at the second level forcing the controlled manipulator to follow the behaviour of a decoupled linear time invariant system, and the problem of converting coordinates is reformulated as a nonlinear dynamic problem and is solved again by making use of robust adaptive techniques.
146 citations
Journal Article•
TL;DR: Estradiol and progesterone receptors were assayed in tumors from 79 patients with primary colorectal and 56 patients with stomach adenocarcinomas, finding that the positivity of at least one receptor in coloreCTal cancers is higher in the female sex and the contrary occurs for stomach cancer.
Abstract: Estradiol and progesterone receptors were assayed in tumors from 79 patients with primary colorectal and 56 patients with stomach adenocarcinomas Eighteen of 79 colorectal cancers contained estradiol receptor, while 34 specimens were positive for progesterone receptor In stomach cancer, the positive samples were 8 for estradiol and 14 for progesterone receptors In both types of tumors, the Kd was in the range of 10-10m for estradiol and 10-9m for progesterone receptor, respectively In colorectal adenocarcinomas, the presence of progesterone receptor seems to be partially correlated to the presence of estradiol receptor while, in stomach tumors, this correlation is lost The positivity of at least one receptor in colorectal cancers is higher in the female sex The contrary occurs for stomach cancer Sucrose gradient centrifugation showed that cytoplasmic estradiol receptor of stomach cancer sedimented at 8S or 4 to 5S at low ionic strength The isoelectric point of stomach cancer estradiol receptor is 65
137 citations
TL;DR: The use of discontinuous control in adaptive model-following continuous control systems with nonlinear time-varying plant withHyperstability theory is described, and the link among the three approaches is explored by studying the error dynamics.
132 citations
TL;DR: A simple increase of digestible carbohydrate without a parallel increase of dietary fibre does not help in improving the metabolic control of diabetic patients and the hypoglycaemic and hypolipidaemic effects of high carbohydrate/high-fibre diets are due principally to dietary fibre.
Abstract: To clarify the separate influences of digestible carbohydrate and of dietary fibre on blood glucose control and serum lipoproteins, 14 diabetic patients (six Type 1 and eight Type 2) were submitted to three weight-maintaining diets for 10 days each: (1) low carbohydrate/low fibre diet with 42% carbohydrate and 20g fibre; (2) high carbohydrate/low fibre diet (carbohydrate 53%, fibre 16g); (3) high carbohydrate/ high fibre diet (carbohydrate 53%, fibre 54 g). In comparison with the low carbohydrate/low fibre diet, the 2-h post-prandial blood glucose and the daily blood glucose profile decreased significantly on the high carbohydrate/high fibre diet, without significant changes during the high carbohydrate/low fibre diet. The diet-induced modifications of blood glucose control were similar in both types of diabetic patients (twoway analysis of variance: F=5.86, p<0.02 for dietary treatment and F=2.09, NS for type of diabetes). Total and lowdensity lipoprotein cholesterol were also decreased after the high carbohydrate/high fibre diet in comparison with the low carbohydrate/low fibre diet (p<0.001 for both), while they were not significantly modified after the high carbohydrate/ low fibre diet. Again the modifications of low density lipoprotein cholesterol induced by diet were similar in both types of diabetic patients (F=10.02, p<0.005 for dietary treatment and F=0.14 for type of diabetes, NS). High-density lipoprotein cholesterol was lower after the two test diets than after the low carbohydrate/low fibre diet. However statistical significance was found only for the high carbohydrate/high fibre diet (p<0.005). In conclusion: (1) a simple increase of digestible carbohydrate without a parallel increase of dietary fibre does not help in improving the metabolic control of diabetic patients; (2) the hypoglycaemic and hypolipidaemic effects of high carbohydrate/high-fibre diets are due principally to dietary fibre.
TL;DR: Results suggest that peripherally administered Ang II elicits antidiuretic hormone (ADH) release by stimulating receptors in the SFO, whereas centrallyadministered Ang II acts at receptors outside the S FO.
TL;DR: In this paper, the complex sorption behavior of water in two widely utilized epoxy-amino thermosets is analyzed and the possibility of performing accelerated ageing on such systems is also discussed.
TL;DR: The correlation between the differentiation of the cortical ER and the arousal in the oocyte of the ability to respond to a pricking stimulus is discussed in the light of an involvement of the cortex ER in the propagation of CG exocytosis.
Abstract: In Xenopus laevis eggs, cisternae shells which surround cortical granules (CG) are part of a cortical endoplasmic reticulum (ER) network. In this paper the origin of such ER shells has been studied in full-grown, progesterone-exposed Xenopus oocytes. Furthermore, the possible role of the cortical ER in the activation process has been investigated by pricking maturing oocytes. It has been shown that in full-grown ovarian oocytes ER CG shells are absent and ER cisternae are extensively and randomly distributed throughout the peripheral cytoplasm, where they appear to be continuous with annulate lamellae (AL). Following hormone treatment, the AL completely disaggregate and the ER cisternae gradually migrate to the cortex where they surround the CG constituting the typical cortical network described in uterine eggs. Furthermore, it has been found that 8 h after progesterone treatment (before the first polar body extrusion) the response to pricking (CG exocytosis) occurs only at the animal half; there is no observable response in the vegetal half. At this time ER shells surround CG only in the animal hemisphere. A complete CG exocytosis occurs following the first polar body emission, when the cortical ER is well organized in the whole oocyte cortex. The correlation between the differentiation of the cortical ER and the arousal in the oocyte of the ability to respond to a pricking stimulus is discussed in the light of an involvement of the cortical ER in the propagation of CG exocytosis.
TL;DR: Bipolar I depressed patients excreted less MHPG than unipolar depressed patients, manic patients, or normal volunteers, and there was only a trend for a low pretreatment MHPG level to be associated with positive response to imipramine hydrochloride or desipramines hydrochlorides in the 19 patients treated with these drugs.
Abstract: • We studied group and subgroup differences in urinary 3-methoxy-4-hydroxyphenylglycol (MHPG) levels in patients with major affective disorder (66 depressed, 13 manic) and normal volunteers (27 subjects). Bipolar I depressed patients excreted less MHPG than unipolar depressed patients, manic patients, or normal volunteers. The mean (±SEM) MHPG excretion rate was 1.44±0.10 mg/day in 19 depressed bipolar I patients, 1.79±0.11 mg/day in 28 unipolar depressed patients, 2.11±0.19 mg/day in 13 manic patients, and 1.85±0.12 mg/day in 27 normal volunteers. Other sources of variance that affected urinary MHPG levels did not explain subgroup or state differences. There was only a trend for a low pretreatment MHPG level to be associated with positive response to imipramine hydrochloride or desipramine hydrochloride in the 19 patients treated with these drugs. The application of this biological test value for prediction of differential response to antidepressant drugs would therefore seem premature.
TL;DR: The results confirmed the potential role of four indices as predictors of response to prophylaxis: a positive family history of bipolar affective illness and a high red blood cell/plasma lithium ratio and the presence of the HLA‐A3 antigen and the Neuroticism Scale of the Eysenck Personality Questionnaire.
Abstract: A set of socio-demographic, clinical, psychological and biological variables was examined in 100 patients diagnosed according to Perris as bipolar affective psychotics or unipolar depressive psychotics, maintained on prophylactic lithium for 2 years and divided into responders and non-responders to this treatment on the basis of strict criteria. The results confirmed the potential role of four indices as predictors of response to prophylaxis: a positive family history of bipolar affective illness and a high red blood cell/plasma lithium ratio (positive predictors) and the presence of the HLA-A3 antigen and a high score on the Neuroticism Scale of the Eysenck Personality Questionnaire (negative predictors). A stepwise discriminant analysis showed that neuroticism score, lithium ratio and HLA-A3 antigen, taken together, correctly classified 74.6% of responders and 68.3% of non-responders. It is hypothesized that these variables as a group may be of practical value in predicting response to lithium prophylaxis, and that pharmacogenetic and, perhaps, personality factors may be involved in treatment failures.
TL;DR: The plasmatic profiles of androgens, estradiol, and progesterone, together with gonads and SSC modifications, have been followed, throughout the post-reproductive period in two Rana esculenta populations, inhabiting a mountain pond and a sea level lagoon.
TL;DR: Two transglutaminase-mediated modifications of the rat epididymal spermatozoon surface were demonstrated in vitro and a specific physiological role for the enzyme, bringing about modifications ofThe rat sperm surface in the seminal fluid environment, is suggested.
Abstract: Two transglutaminase-mediated modifications of the rat epididymal spermatozoon surface were demonstrated in vitro. Transglutaminase was effective in promoting the binding of spermidine to the sperm. Moreover, the enzyme, by reacting with one of the major proteins secreted by the rat seminal vesicle epithelium, produced a modified form of the protein with a higher molecular weight and the capability of binding to the sperm cells. A specific physiological role for the enzyme, bringing about modifications of the rat sperm surface in the seminal fluid environment, is suggested.
TL;DR: The internal lherzolites, representing the base of the Northern Apennine ophiolite sequences, show a significant residual character and are generally associated with normal MORB.
TL;DR: High serum ferritin concentrations in breast carcinoma patients might be attributed to stromal reaction rather than to tumour synthesis, and lactoferrin might be used as a pointer to benign lesions.
Abstract: An immunoperoxidase staining technique was used for detecting three major iron binding proteins (ferritin, transferrin and lactoferrin) in 40 breast carcinoma cases and six benign breast proliferative lesions. Ferritin staining was detected mainly in connectival stroma and in histiocytes surrounding neoplastic cells. Few and faint ferritin positivities were also detected in neoplastic cells of 20 carcinoma cases. Transferrin was found inconsistently in myoepithelial cells surrounding normal ductules, or around neoplastic ducts of ductal in situ carcinoma. In eight carcinoma cases, transferrin staining was also positive in neoplastic cells. Lactoferrin was detected only in normal breast epithelial cells and in benign breast proliferative lesions. These immunohistochemical findings may suggest that raised serum ferritin concentrations in breast carcinoma patients might be attributed to stromal reaction rather than to tumour synthesis. Transferrin staining of neoplastic cells in these carcinoma cases appears to be very intriguing, particularly since transferrin is considered an obligate requirement for growing cells, and transferrin receptors have been demonstrated only in dividing cells. On the basis of the immunohistochemical data, lactoferrin might be used as a pointer to benign lesions.
TL;DR: It is concluded that porins can effectively contribute to complement activation and to subsequent biological events induced by gram-negative bacteria.
Abstract: The effect of porins purified from Salmonella typhimurium on the complement system was investigated both in vitro and in vivo. Incubation of porins with either human or guinea pig serum resulted in the consumption of the total complement activity when an amount of porins ranging from 8 to 10 micrograms per 100 microliters of serum was used. The activation of the complement system was temperature dependent, suggesting an active process rather than passive adsorption of the complement components by porins. In addition, the activation had a fast kinetic and proceeded mainly through the classical pathway. This conclusion is supported by the consumption of C1s and C4 in normal human serum treated with porins and also by the depletion of C3 activity in the C1s-deficient serum which was marked only when purified C1s was added to the serum before incubation with porins. Injection of 100 micrograms of porins into guinea pigs induced profound complement consumption at 6 h postinjection that persisted up to 12 h. We conclude from this study that porins can effectively contribute to complement activation and to subsequent biological events induced by gram-negative bacteria.
TL;DR: In this paper, the cure behavior of commercial grade TGDDM-DDS mixtures of compositions ranging from 10 to 100 phr of hardener and the thermal polymerization of the epoxy component are analyzed by means of differential scanning calorimetry.
Abstract: The cure behavior of commercial grade TGDDM–DDS mixtures of compositions ranging from 10 to 100 phr of hardener and the thermal polymerization of the epoxy component are analyzed by means of differential scanning calorimetry. The kinetic parameters and heats of reaction determined in isothermal and dynamic scans suggest that DDS primary amine addition and epoxide etherification dominate the cure reactions. The primary amine epoxide addition is characterized by overall heat of reaction (referred to the weight of the epoxy component) of 255 cal/g and by an activation energy of 16.6 kcal/mol. The corresponding values for the etherification reaction are, respectively, 170 cal/g and 41 kcal/mol. A method of derivation of the epoxide conversion from the heat evolved in DSC thermal scans of these systems is presented. The results are in good agreement with independent IR determinations. The steady shear and oscillatory viscosity measurements and the calorimetric analysis of the isothermal cure at 140°C, 160°C, and 180°C of a TGDDM–DDS mixture containing 35 phr of hardener indicate that gelation is principally governed by the primary amine addition. The gelation limits calculated in isothermal tests by combining the calorimetric analysis and the theory describing the nonlinear copolymerization of the tetrafunctional TGDDM with an essentially difunctional DDS were in good agreement with the values experimentally determined through rheological measurements.
TL;DR: A fixation of the size distribution of the exons which code for the interstitial collagen helical domains is found despite the persistence in these exons of sequence elements that should have favoured recombinational rearrangements, and contrasts with the variations in the pattern of sizes of some exons coding for the amino and carboxyl propeptides of these collagens.
Abstract: Type III collagen is often found in the same tissues as type I collagen, yet the function and nature of the fibrils formed by the two collagens differ markedly1–3. To understand the evolutionary history of the collagen gene family in more detail, we isolated the gene for type III collagen and compared its structure with that of the gene for α2(I) collagen4–9. This comparison points to a remarkable conservation in the size distribution of the exons coding for the helical part of these two collagen polypeptides: equivalent amino acid segments in the helical domain of each polypeptide are encoded by exons of equal sizes in each gene. This suggests that after the interstitial collagen genes had been duplicated from a common ancestor about 2–5 × 108 years ago10, no recombinations between these exons were tolerated, although the same recombinational phenomena must have played an important part in shaping the structure of the progenitor for these genes. This fixation of the size distribution of the exons which code for the interstitial collagen helical domains is found despite the persistence in these exons of sequence elements that should have favoured recombinational rearrangements, and contrasts with the variations in the pattern of sizes of some exons coding for the amino and carboxyl propeptides of these collagens.
TL;DR: The results suggest that adults able to absorb galactose from a lactose-containing diet are especially susceptible to senile or presenile cataract.
TL;DR: Seasonal plasma progesterone, androstenedione, estrone, and 17 beta-estradiol concentrations in the female Rana esculenta were determined by radioimmunoassay during the 1979 and 1981 seasons to establish relationships between seasonal steroid levels and ovarian activity.
TL;DR: Investigating a chronically lymphedematous leg of a 75-year-old man revealed a lack of cellular immune response confined to the involved lower limb, suggesting regional disorders of immune surveillance are thought to play an important role in the early stages of Kaposi's sarcoma.
Abstract: Kaposi's sarcoma appeared on a chronically lymphedematous leg oi a 75-year-old man. lmrnunologic investigations revealed a lack of cellular immune response confined to the involved lower limb. Regional disorders of immune surveillance are thought to play an important role in the early stages of Kaposi's sarcoma.
TL;DR: Most mutants in the region coding for the TpsiCG stem-loop show a reduced gene expression associated with lack of processing of the primary transcriptional products; in the oocytes these are rapidly degraded, with a half-life considerably shorter than that of wild-type tRNA molecules.
TL;DR: In this paper, a simple model based on energy considerations has been tested to predict the maximum contact force during a low-velocity impact between an impactor and a composite plate, i.e., the total energy applied during the impact is the governing parameter of the phenomenon, rather than the impactor speed or mass.
TL;DR: Refractive changes in 61 children with unilateral amblyopia who were followed-up for 10 years were described, and in each case the change was towards myopia.
Abstract: The authors describe refractive changes in 61 children with unilateral amblyopia who were followed-up for 10 years. In each case the change was towards myopia. The various factors affecting postnatal development of the eye are discussed.
TL;DR: The results show that antimony deposits appear first in SER vesicles between the plasma membrane and CGs and then spread to the rest of the egg cytomembranes, which corroborate the hypothesis that in Xenopus the cortical SER network is the first intracellular site where calcium is released at activation.
Abstract: In the egg of Xenopus laevis a cortical network of smooth endoplasmic reticulum (SER) surrounds and interconnects each cortical granule (CG) (Campanella and Andreuccetti, '77). This network is a possible intracellular site of calcium storage to be called into action for CG exocytosis. In our experiments, Xenopus eggs, unfertilized or activated by pricking or by calcium ionophore A 23187, have been fixed in osmium-pyroantimonate for calcium localization.
Our data show that deposits can be detected only in activated egs. The calcium chelator edetate (EGTA) and x-ray microprobe analysis demonstrate that they contain calcium. Deposits are found on liposomes and on all intraovular cytomembranes, which therefore appear to be possible sites of calcium sequestration. In the case of ionophore-activated eggs, deposits are detectable independently of the presence of extracellular calcium. These data show that in Xenopus at activation an intracellular liberation of calcium occurs similar to that described in other species.
Furthermore, the fact that antimony deposits are observed only after activation makes Xenopus eggs appropriate material in which to follow the temporal and spatial sequence of appearance of the deposits during the early stages of activation. Our results show that antimony deposits appear first in SER vesicles between the plasma membrane and CGs and then spread to the rest of the egg cytomembranes. These data corroborate our hypothesis that in Xenopus the cortical SER network is the first intracellular site where calcium is released at activation. The possible mechanism of calcium release and propagation along the egg cortex is discussed.