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P Moretti

Publications and source records attributed to P Moretti.

At least 19 recordsLinked to original sources
PubMed2006

Room-temperature continuous-wave operation of Ti:sapphire buried channel-waveguide lasers fabricated via proton implantation.

Fabrication and laser operation of proton-implanted Ti:sapphire buried channel waveguides is reported for the first time to our knowledge. Without any postimplantation annealing of the structures, continuous laser operation near 780 nm was demonstrated at room temperature at an absorbed pump power threshold of 230 mW. Single-transverse-mode laser emission was observed with measured beam propagation factors M(2)(x) and M(2)(y) of 1.5 and 1.2, respectively. An output power of 12.4 mW for 1 W pump power was obtained with an output coupler of 4.6% transmission at the signal wavelength. Higher output powers were measured in waveguides with larger cross sections exhibiting multimode laser emission.

Journal Article↗
PubMed2006

Prediction of theoretical plate number in isothermal gas chromatographic analysis on capillary columns.

A method for the prediction of the efficiency of gas chromatographic analysis in isothermal conditions by using experimental data of 1-alcohols and n-alkanes measured on capillary columns filled with polar and non-polar stationary phases in isothermal and isobaric conditions is described. The theoretical plate height trend indicates the change of separation efficiency as a function of inlet pressure and column temperature. By evaluating the variation of the diffusion coefficients of the analysed compounds into the mobile and stationary phase it is possible to predict the column efficiency and the number of theoretical plates at any temperature.

Chromatography, Gas↗
PubMed2005

Classification and comparison of capillary columns by determination of the solution enthalpy of polar and non polar probes.

The behaviour and separation characteristics of capillary columns containing different stationary phases (bonded methyl- and methylphenylsiloxanes and polyglycols, and carbon layer and porous polymer) were classified and compared by measuring the values of the solution enthalpy DeltaHs of n-alkanes and 1-alcohols at various temperatures. The difference in DeltaHs values between straight-chain 1-alcohols and n-alkanes with the same number of carbon atom (DeltaDeltaHs) does not change with changing temperature when gas-liquid partition stationary phases are used, but depends on the column composition and polarity and therefore permits to evaluate the influence of polarity on the solute-solvent interaction. The trend of the DeltaDeltaHs values is correlated with that of the DeltaC parameter and with the McReynolds' polarity constants.

Adsorption↗
PubMed2005

Cerebral folate deficiency with developmental delay, autism, and response to folinic acid.

The authors describe a 6-year-old girl with developmental delay, psychomotor regression, seizures, mental retardation, and autistic features associated with low CSF levels of 5-methyltetrahydrofolate, the biologically active form of folates in CSF and blood. Folate and B12 levels were normal in peripheral tissues, suggesting cerebral folate deficiency. Treatment with folinic acid corrected CSF abnormalities and improved motor skills.

Adaptation, Physiological↗
PubMed2005

Effect of injected sample amount on the shape of chromatographic peaks under condition of linear partition isotherm.

In a previous paper a model function was tested in order to approximate the peak shape obtained on non-polar column by injecting different compounds. The simulation of the symmetrical or non-symmetrical shape of gas chromatographic peaks was satisfactory. In this paper, the influence of the amount of injected substance was investigated at different values of inlet pressure and carrier gas velocity, in order to evaluate the relative contribution to the total peak area and shape of the symmetrical distribution due to partition phenomena and of the non-symmetrical and tailing distribution due to adsorption-desorption kinetics. The effect of the molecular mass and of the chain length of compounds belonging to the homologous series of 1-alcohols and n-alkanes on the adsorption phenomena was evaluated.

Adsorption↗
PubMed2004

Prediction of retention times and efficiency in linear gradient programmed pressure analysis on capillary columns.

A method for the prediction of the retention time and the resolution of chromatographic peaks in different experimental conditions by starting from few experimental data measured in isothermal and isobaric analyses was published previously. In this paper, the same mathematical model was implemented for calculating the retention times and the column efficiency in programmed pressure runs. Some models originated from the Golay equation and reported in the literature are compared, and a new modified equation for the calculation of the peak width at half height is proposed. The procedure for the prediction of the retention time and the peak width at half height at programmed pressure of the carrier gas and different column temperature and linear gradient by using retention data of different compounds obtained in few isobaric runs is described. The prediction of the retention time and the separation efficiency of compounds with different polarity gave good results for the programmed pressure runs with linear gradient. The effect of the variation of the initial parameters of the experimental analyses and of the mathematical model on the accuracy of the prediction has been evaluated.

Chromatography, Gas↗
PubMed2004

Prediction of retention times in linear gradient temperature and pressure programmed analysis on capillary columns.

The simultaneous temperature and inlet pressure programming (TPP) in gas chromatographic analysis decreases the retention time and the maximum value of temperature required for the elution of high boiling substances. Therefore, compounds sensitive to thermal degradation can be better analysed and column ageing is reduced. However, the empirical choice of proper analysis conditions requires many preliminary runs; this paper describes a procedure for the theoretical prediction of retention times in TPP using few preliminary runs carried out in isobaric and isothermal conditions. The used program permits the prediction of the retention times of the compounds analysed with any different TPP run carried out within the temperature and pressure ranges investigated with the preliminary runs. The influence of various analytical parameters on the accuracy of the prediction values was investigated. The proposed model also predicts the relative position in the chromatogram of closely eluting peaks and the possible coincidence of retention times or inversion of the elution order with changing temperature. It is also possible to foresee the analytical conditions, which offer a baseline separation of all of the peaks of the sample.

Chromatography, Gas↗
PubMed2004

Evaluation and prediction of the shape of gas chromatographic peaks.

The evaluation and prediction of the shape of asymmetric gas chromatographic peaks is important as the knowledge of the amount of tailing permits to foresee the resolution between closely eluting peaks and to select the best analytical conditions for an efficient and rapid separation. A model function was tested in order to approximate the true peak shape obtained on non-polar column by injecting different compounds. The trend of the parameters involved in the used equation has been investigated as a function of column temperature and inlet pressure. The reproduction of the symmetrical or asymmetrical shape of gas chromatographic peaks is satisfactory and the method also permits to predict the shape of peaks obtained in different conditions of temperature and pressure.

Chromatography, Gas↗
PubMed2004

Novel insertional presenilin 1 mutation causing Alzheimer disease with spastic paraparesis.

A four-generation pedigree exhibiting early-onset autosomal dominant Alzheimer disease (AD) with spastic paraplegia, dystonia, and dysarthria due to a novel 6-nucleotide insertional mutation in exon 3 of the presenilin 1 gene (PS1) is described. Serial examinations, PET scans, and autopsy revealed that the mutation in this highly conserved portion of PS1 causes an aggressive dementia that maintains the usual regional hierarchy of disease pathology while extending abnormalities into more widespread brain areas than typically seen in AD.

Adult↗
PubMed2004

Prediction of the resolution of capillary columns in different conditions of inlet pressure and temperature.

A procedure previously described for the prediction of the plate height of capillary columns operated at different inlet pressure of the carrier gas and at various column temperatures by using few retention data measured under isobaric conditions was modified and improved in order to permit the prediction of the retention times and of the peak widths at various heights. It is therefore possible to calculate the ratio, delta, between the peak width at different heights and the peak width at half height, whose value is used to predict the resolution at different height of two closely eluting peaks. It was found that the delta values do not depend on temperature and inlet pressure and are a characteristic of the used column; they can therefore be used in order to calculate the resolution in any temperature and inlet pressure condition. The method was used to predict the retention time, the peak width and the resolution of polar and non-polar compounds (alkanes, alkenes, chloroalkanes, alcohols, ketones) on capillary columns of different length and polarity by using as the starting data retention and width values measured in three isobaric runs only.

Chromatography, Gas↗
PubMed2003

Prediction of the plate height of capillary columns operated at any inlet pressure of the carrier gas by using few retention data measured under isobaric conditions.

Programming inlet pressure in gas chromatography permits to decrease the analysis time without changing the elution order of compounds of different polarity whose relative retention changes with changing temperature. The choice of the best values of the inlet pressure and flow-rate of the carrier gas often requires many preliminary analyses with different parameters to be carried out. A method for the prediction of the separation by starting from few experimental data measured in isothermal and isobaric conditions decreases the time required for the optimisation of the analysis. The efficiency of the separation depends on the change of the theoretical plate height at various pressures and temperatures, due to pressure drop along the column. By calculation of the diffusion coefficients of the analysed compounds into the mobile and stationary phase it is possible to evaluate the column efficiency and predict the number of theoretical plates at any inlet pressure. A procedure for the prediction of the plate height of a capillary column at any inlet pressure of the carrier gas and column temperature by using retention data of polar and non-polar compounds (1-alcohols and linear alkanes) obtained in few isobaric runs is described.

Chromatography, Gas↗
PubMed2002

Clinical and serological associations of ribosomal P autoantibodies in systemic lupus erythematosus: prospective evaluation in a large cohort of Italian patients.

OBJECTIVE: To verify the association of ribosomal anti-P antibodies (anti-P), as detected by a sensitive ELISA, with serological findings and clinical manifestations, including neuropsychiatric involvement evaluated according to the American College of Rheumatology (ACR) nomenclature, in a large cohort of patients with systemic lupus erythematosus (SLE). METHODS: Anti-P were evaluated in the serum of 149 consecutive Italian SLE patients by an ELISA using a multiple antigen peptide carrying four copies of a common P0, P1 and P2 epitope. A complete laboratory evaluation and clinical examination were performed in each patient. In addition, all patients underwent an accurate neuropsychiatric and neuropsychological assessment performed by trained specialists according to the 1999 ACR suggestions. RESULTS: Serum anti-P were detected in 18/149 patients (12.1%). The anti-P prevalence was similar (11.7%) when the analysis was performed in a larger series of sera including 82 additional SLE patients, who were not included in the clinical study. The age of anti-P-positive patients at disease onset was less than 33 yr and, in comparison with the anti-P-negative patients, these patients showed more active disease activity and a higher prevalence of photosensitivity and malar and discoid rash. A strong association between IgG anticardiolipin antibodies and anti-P was also found. However, anti-P were associated with neither neuropsychiatric syndromes nor cognitive impairment. CONCLUSION: This study does not seem to confirm the described association of anti-P with SLE neuropsychiatric manifestations. However, it supports the anti-P association with different skin manifestations as well as the presence of anticardiolipin in a subset of patients with SLE characterized by early disease onset.

Adolescent↗
PubMed2001

Multiple interactions in Sir protein recruitment by Rap1p at silencers and telomeres in yeast.

Initiation of transcriptional silencing at mating type loci and telomeres in Saccharomyces cerevisiae requires the recruitment of a Sir2/3/4 (silent information regulator) protein complex to the chromosome, which occurs at least in part through its association with the silencer- and telomere-binding protein Rap1p. Sir3p and Sir4p are structural components of silent chromatin that can self-associate, interact with each other, and bind to the amino-terminal tails of histones H3 and H4. We have identified a small region of Sir3p between amino acids 455 and 481 that is necessary and sufficient for association with the carboxyl terminus of Rap1p but not required for Sir complex formation or histone binding. SIR3 mutations that delete this region cause a silencing defect at HMR and telomeres. However, this impairment of repression is considerably less than that displayed by Rap1p carboxy-terminal truncations that are defective in Sir3p binding. This difference may be explained by the ability of the Rap1p carboxyl terminus to interact independently with Sir4p, which we demonstrate by in vitro binding and two-hybrid assays. Significantly, the Rap1p-Sir4p two-hybrid interaction does not require Sir3p and is abolished by mutation of the carboxyl terminus of Rap1p. We propose that both Sir3p and Sir4p can directly and independently bind to Rap1p at mating type silencers and telomeres and suggest that Rap1p-mediated recruitment of Sir proteins operates through multiple cooperative interactions, at least some of which are redundant. The physical separation of the Rap1p interaction region of Sir3p from parts of the protein required for Sir complex formation and histone binding raises the possibility that Rap1p can participate directly in the maintenance of silent chromatin through the stabilization of Sir complex-nucleosome interactions.

Binding Sites↗
PubMed2001

The 4P-syndrome. Case description and literature review.

The microdeletion 4p16 has been found in two rare syndromes. Until now they were considered as two different syndromes: the Wolf-Hirschhorn syndrome (WHS) and the Pitt-Rogers-Danks (PRDS) syndrome characterized by a growth retardation before and after birth, microcrania, seizures, characteristic face with thin mouth, maxillary hypoplasia, short and large philtrum, characteristic nose and mental retardation. A case with 4p-16 microdeletion with phenotype characteristics similar to PRDS is reported. The patients described as PRDS are sometimes less seriously affected than patients with WHS. In fact, cases of death are not indicated in the first year of life, internal malformations are less frequent and the face lacks the typical Greek warrior helmet Recent studies have shown that WSS and PRDS are due to the absence of similar if not identical genetic segments and the clinical differences observed could be the outcome of an allele variation on the remaining homologous part.

Abnormalities, Multiple↗
PubMed2000

Determination of enteroviruses, hepatitis A virus, bacteriophages and Escherichia coli in Adriatic Sea mussels.

The aim of the present study was to evaluate the incidence of enteric viruses in mussels and to verify the possibility of using phages as indirect indicators of mussel viral contamination. Mussels (36 samples) collected from three different areas of the Adriatic Sea were analysed to determine the following parameters: Escherichia coli, somatic coliphage (T6 phage), F-Plus (MS2 phage), B40-8 (phage of Bacteroides fragilis), enteroviruses and hepatitis A virus. Most of the results of the bacteriological analysis (most probable number (MPN) ml-1) were in accordance with the bacteriological limits established by European law, with the exception of seven samples. The bacteriophage analyses were always negative for F-Plus and B40-8, with the exception of a few samples, whereas the somatic coliphages were generally between 0 and 20 MPN g-1, with the exception of two samples (110 MPN g-1). The virological analysis showed five samples positive for the presence of enteroviruses and 13 for the presence of hepatitis A virus (in three samples both viruses were present). Most of these samples presented acceptable bacteriological parameters and the bacteriophages were absent or their value was generally very low. The results show that the detection of E. coli and phages does not seem to be a good indicator of viral contamination.

Animals↗
PubMed1998

Bilateral medial frontal infarction in a case of azygous anterior cerebral artery stenosis.

We describe the unusual case of a 63-year-old woman with a history of arterial hypertension who presented a sudden weakness of the lower limbs followed by mutism, akinesia and dyspraxia. Magnetic resonance images showed a bilateral medial frontal infarction. Digital subtraction angiography documented a right azygous anterior cerebral artery with severe stenosis in its sub-callosal tract; the left anterior cerebral artery showed mild hypoplasia with only sub-frontal and fronto-polar branches. No embolic source was documented. Afterwards the patient presented a gradual and partial recovery of both motor and cognitive functions.

Angiography, Digital Subtraction↗
PubMed1996

Silencing of genes at nontelomeric sites in yeast is controlled by sequestration of silencing factors at telomeres by Rap 1 protein.

Rap1p binds to silencer elements and telomeric repeats in yeast, where it appears to initiate silencing by recruiting Sir3p and Sir4p to the chromosome through interactions with its carboxy-terminal domain. Sir3p and Sir4p interact in vitro with histones H3 and H4 and are likely to be structural components of silent chromatin. We show that targeting of these Sir proteins to the chromosome is sufficient to initiate stable silencing either at a silent mating-type locus lacking a functional silencer element or at a telomere in a strain in which the Rap1p carboxy-terminal silencing domain has been deleted. Silencing by Sir protein targeting can also be initiated at a telomere-proximal site (ADH4), but is much weaker at an internal chromosomal locus (LYS2). Strikingly, deletion of the Rap1p silencing domain, which abolishes telomeric silencing, improves targeted silencing at LYS2 by both Sir3p and Sir4p, while weakening the silencing activity of these proteins at or near a telomere. This effect may result from the release of Sir proteins from the telomeres, thus increasing their effective concentration at other chromosomal sites. We suggest that telomeres and Rap1p serve a regulatory role in sequestering Sir proteins at telomeres, controlling silencing at other loci in trans and preventing indiscriminate gene silencing throughout the genome.

Chromosomes, Fungal↗