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M Pavan

Publications and source records attributed to M Pavan.

At least 19 recordsLinked to original sources
PubMed2006

Measurement of the p to s wave branching ratio of 187Re beta decay from beta environmental fine structure.

The mixed occurrence of s-wave and p-wave contributions in a first forbidden unique Gamow-Teller beta decay has been investigated for the first time by measuring the beta environmental fine structure (BEFS) in a 187Re crystalline compound. The experiment has been carried out with an array of eight AgReO4 thermal detectors operating at a temperature of approximately 100 mK. A fit of the observed BEFS spectrum indicates the p-wave electron emission as the dominant channel. The complete understanding of the BEFS distortion of the 187Re beta decay spectrum is crucial for future experiments aiming at the precise calorimetric measurement of the antineutrino mass.

Journal Article↗
PubMed2006

Validation of a QSAR model for acute toxicity.

In the present study, a quantitative structure--activity relationship (QSAR) model has been developed for predicting acute toxicity to the fathead minnow (Pimephales promelas), the aim being to demonstrate how statistical validation and domain definition are both required to establish model validity and to provide reliable predictions. A dataset of 408 heterogeneous chemicals was modelled by a diverse set of theoretical molecular descriptors by using multivariate linear regression (MLR) and Genetic Algorithm-Variable Subset Selection (GA-VSS). This QSAR model was developed to generate reliable predictions of toxicity for organic chemicals not yet tested, so particular emphasis was given to statistical validity and applicability domain. External validation was performed by using OECD Screening Information Data Set (SIDS) data for 177 High Production Volume (HPV) chemicals, and a good predictivity was obtained (=72.1). The model was evaluated according to the OECD principles for QSAR validation, and compliance with all five principles was established. The model could therefore be useful for the regulatory assessment of chemicals. For example, it could be used to fill data gaps within its chemical domain and contribute to the prioritization of chemicals for aquatic toxicity testing.

Animals↗
PubMed2006

Validation of counter propagation neural network models for predictive toxicology according to the OECD principles: a case study.

The OECD has proposed five principles for validation of QSAR models used for regulatory purposes. Here we present a case study investigating how these principles can be applied to models based on Kohonen and counter propagation neural networks. The study is based on a counter propagation network model that has been built using toxicity data in fish fathead minnow for 541 compounds. The study demonstrates that most, if not all, of the OECD criteria may be met when modeling using this neural network approach.

Animal Use Alternatives↗
PubMed2005

New limit on the neutrinoless betabeta decay of 130Te.

We report the present results of CUORICINO, a search for neutrinoless double-beta (0nu betabeta) decay of 130Te. The detector is an array of 62 TeO2 bolometers with a total active mass of 40.7 kg. The array is cooled by a dilution refrigerator shielded from environmental radioactivity and energetic neutrons, operated at approximately 8 mK in the Gran Sasso Underground Laboratory. No evidence for (0nu betabeta) decay was found and a new lower limit, T(1/2)(0nu) > or = 1.8 x 10(24) yr (90% C.L.) is set, corresponding to [m(nu)] < or = 0.2 to 1.1 eV, depending on the theoretical nuclear matrix elements used in the analysis.

Journal Article↗
PubMed2004

Total ranking models by the genetic algorithm variable subset selection (GA-VSS) approach for environmental priority settings.

Total order ranking (TOR) strategies, which are mathematically based on elementary methods of discrete mathematics, seem to be attractive and simple tools for performing data analysis. Moreover order-ranking strategies seem to be a very useful tool not only to perform data exploration but also to develop order ranking models, a possible alternative to conventional quantitative structure-activity relationship (QSAR) methods. In fact, when data material is characterised by uncertainties, order methods can be used as alternative to statistical methods such as multilinear regression (MLR), because they do not require specific functional relationships between the independent and dependent variables (responses). A ranking model is a relationship between a set of dependent attributes, experimentally investigated, and a set of independent attributes, i.e. model attributes, which are calculated attributes. As in regression and classification models, the variable selection model is one of the main steps in finding predictive models. In this work the genetic algorithm-variable subset selection (GA-VSS) approach is proposed as the variable selection method for searching for the best ranking models within a wide set of variables. The models based on the selected subsets of variables are compared with the experimental ranking and evaluated by the Spearman's rank index. A case study application is presented on a TOR model developed for polychlorinated biphenyl (PCB) compounds, which have been analysed according to some of their physicochemical properties which play an important role in their environmental impact.

Journal Article↗
PubMed2003

Bolometric bounds on the antineutrino mass.

High statistics calorimetric measurements of the beta spectrum of 187Re are being performed with arrays of silver perrhenate crystals operated at low temperature. After a substantial modification of the experimental setup, a new measurement with ten silver perrhenate microbolometers has been running since July 2002. The crystals have masses around 300 microg and their average FWHM energy resolution is of 28.3 eV at the beta end point. The Kurie plot collected during 4485 h x mg effective running time has an end-point energy of 2466.1+/-0.8(stat)+/-1.5(syst) eV, while the half lifetime of the decay is found to be 43.2+/-0.2(stat)+/-0.1(syst) Gy. These values are the most precise obtained so far for 187Re. The best fit value for m(2)(nu(e)) is 147+/-237(stat)+/-90(syst) eV(2), which corresponds to an upper limit for the electron antineutrino mass m(nu(e))< or =21.7 eV at 90% C.L.

Journal Article↗
PubMed2003

Study on anaerobic and aerobic degradation of different non-ionic surfactants.

Six alcohol ethoxylates (C5E2, C6E4, C7E4, C8E2, C8E4, C10E4) and two fatty acid esters were tested at lab-scale for degradation in anaerobic and aerobic conditions and oxygen uptake rate (OUR). Anaerobic removal of C5E2, C6E4 and C7E4 improved with increasing number of ethoxy groups (E) and decreasing length of the alkyl chain (C). Their aerobic removal was also great but lower than the anaerobic values. C8E2, C8E4 and C10E4 were adsorbed on sludge but not degraded in anaerobic conditions, while they were efficiently removed under aerobiosis. The fatty acid esters were removed to a level between the two alcohol ethoxylates groups in both anaerobiosis and aerobiosis. The measured OUR confirmed the different behaviours of the three groups of compounds.

Alcohols↗
PubMed2003

Prediction of aromatic amines mutagenicity from theoretical molecular descriptors.

In the present research the mutagenicity data (Ames tests TA98 and TA100) for various aromatic and heteroaromatic amines, a data set extensively studied by other quantitative structure-activity relationship (QSAR)-authors, have been modeled by a wide set of theoretical molecular descriptors using linear multivariate regression (MLR) and genetic algorithm-variable subset selection (GA-VSS). The models have been calculated on a subset of compounds selected by a D-optimal experimental design. Moreover, they have been validated by both internal and external validation procedures showing satisfactory predictive performance. The models proposed here can be useful in predicting data and setting a testing priority for those compounds for which experimental data are not available or are not yet synthesized.

Algorithms↗
PubMed2001

Interleukin-3 stimulates migration and proliferation of vascular smooth muscle cells: a potential role in atherogenesis.

BACKGROUND: Cytokines released by activated T lymphocytes are key regulators of chronic inflammatory response, including atherosclerosis. The aim of this study was to investigate the presence of interleukin-3 (IL-3) in lymphocytes infiltrating the atherosclerotic plaque and the effect of this cytokine on primary vascular smooth muscle cells (SMCs). METHODS AND RESULTS: Twenty atherosclerotic carotid arterial specimens and 5 early atherosclerotic lesions from the internal carotid were manually minced to fragments, and T lymphocytes infiltrating the atherosclerotic plaque were isolated on solid-phase anti-CD3 polystyrene plates. Southern blot analysis demonstrated that in all samples, lymphocytes expressed IL-3 and IL-2 receptor alpha-chain transcripts, indicating that in this context, the activated T lymphocytes may release IL-3. We further analyzed the expression of the IL-3 receptor and the biological effects exerted by the ligand on vascular SMCs. ss-IL-3-transducing subunit was detected both on cultured SMCs and on endothelial cells and SMCs within atheroma. The analysis of the IL-3-induced biological effects demonstrated that it was able to trigger both mitogenic and motogenic signals. Moreover, we demonstrated that the addition of PD98059, a known inhibitor of the MAP-extracellular signaling-regulated/MAP kinase pathway, completely inhibited IL-3-mediated MAP kinase activation and IL-3-induced migration and proliferation. Finally, IL-3 was found to stimulate vascular endothelial growth factor (VEGF) gene transcription. CONCLUSIONS: IL-3, expressed by activated T lymphocytes infiltrating early and advanced atherosclerotic plaques, may sustain the atherosclerotic process either directly, by activating SMC migration and proliferation, or indirectly, via VEGF production.

Arteriosclerosis↗
PubMed2001

Prevalence rate of urinary incontinence in community-dwelling elderly individuals: the Veneto study.

BACKGROUND: Urinary incontinence (UI) is a common problem in elderly people, due mainly to functional impairments and concurrent medical diseases. Few studies, however, have assessed the prevalence of UI in noninstitutionalized individuals. The objectives of the present work were to estimate the prevalence of UI in a community-based population of elderly Italians and to determine the associated physical, social, and psychological factors. METHODS: A random sample of noninstitutionalized men (n = 867) and women (n = 1531), aged 65 years and older, from the Veneto region of northeastern Italy, were interviewed at home, using an extensive multidisciplinary questionnaire, to assess their quality of life and social, biological, and psychological correlates. RESULTS: The prevalence rate of UI was of 11.2% among men and of 21.6% among women. Among those reporting the condition, approximately 53% of women and 59% of men reported experiencing incontinence daily or weekly. Association of UI was found for participants older than 70 years in both men (odds ratio [OR] 2.49, 95% confidence interval [CI] 1.45-4.28) and women (OR 1.49, 95% CI 1.11-2.02). Three of the medical conditions investigated were associated with increases in the odds in women, namely chronic obstructive pulmonary disease (OR 1.53, 95% CI 1.11-2.12), Parkinsonism (OR 2.27, 95% CI 1.14-4.54), and hip fracture (OR 1.38,95% CI 1.02-1.88), whereas chronic diarrhea was the only condition associated with UI in men (OR 6.92, 95% CI 2.22-21.5). Participants with a physical disability were two times more likely to report incontinence, and the odds were increased by 50% in women who had sleep disturbances. CONCLUSIONS: Incontinence is highly prevalent in the Italian elderly population, and several common chronic conditions are significantly associated with it. Moreover, very few people with incontinence seek health care or are aware of potential treatments.

Age Distribution↗
PubMed1998

Sleep complaints in community-dwelling older persons: prevalence, associated factors, and reported causes.

OBJECTIVES: To determine the prevalence rates of self-reported sleep complaints and their association with health-related factors. DESIGN: A cross-sectional study. SETTING: People living in the community. PARTICIPANTS: A total of 2398 noninstitutionalized individuals, aged 65 years and older, residing in the Veneto region, northeast Italy. MEASUREMENTS: Odds ratios for the association of sleep complaints with potential risk factors. RESULTS: The prevalence of insomnia was 36% in men and 54% in women, with increased risks for women (odds ratio (OR) = 1.69, 95% CI: 1.3-2.1), depression (OR = 1.93, 95% CI, 1.5-2.5), and regular users of sleep medications (OR = 5.58, 95% CI, 4.3-7.3). About 26% of men and 21% of women reported no sleep complaints. Night awakening, reported by about two-thirds of the participants, was the most common sleep disturbance. Women and regular users of sleep medications had significantly increased odds for insomnia and for not feeling rested upon awakening in the morning. Depressive symptomatology was more strongly associated with insomnia and night awakening than with awakening not rested, whereas physical disability was more strongly associated with awakening not rested than with the other two sleep disturbances. CONCLUSION: Our findings show that sleep complaints, highly common among older Italians, are associated with a wide range of medical conditions and with the use of sleep medications. Further longitudinal studies are needed to investigate the causes and the negative health consequences of sleep disturbances to improve both the diagnosis and treatment.

Aged↗
PubMed1998

Prevalence rates of hearing impairment and comorbid conditions in older people: the Veneto Study.

OBJECTIVES: To investigate the prevalence rate of hearing impairment, assessed by both the Sanders' questionnaire and the speech audiometry test, and its association with health-related factors in the older population of the Veneto region of Italy. DESIGN: A cross-sectional survey. SETTING: A community-based population. PARTICIPANTS: 2398 noninstitutionalized individuals aged 65 years and older residing in the Veneto region of Italy. MEASUREMENTS: Prevalence rates of hearing impairment and odds ratios for its association with potential risk factors. MAIN RESULTS: The prevalence of self-reported hearing impairment at home was 8.1% in men and 7.4% in women, and in a social environment it was 11.1% and 9.3%, respectively. Women were less likely to report hearing difficulties in both environments, and increased risks were found for depression, age, and poor self-rated health. Participants with diabetes or cognitive impairment had increased odds only at home, in contrast to people with a low education level, who had increased odds only in a social environment. The prevalence assessed by speech audiometry was 19% in both sexes. Increased age, diabetes, and poor self-rated health were associated with impaired speech intelligibility, cognitive impairment was associated with 4-fold increased odds among past users of alcohol, and men with a low education level were about three times as likely as others to have hearing impairment. CONCLUSIONS: Speech audiometry testing detected a higher prevalence of hearing impairment than use of a self-reported questionnaire and was associated with poor self-rated health, history of diabetes, and cognitive impairment among past users of alcohol and among men with low levels of education. The association between hearing deficit and depressive symptomatology was confirmed only with self-reported hearing impairment.

Aged↗
PubMed1996

Self-report of difficulty in performing functional activities identifies a broad range of disability in old age.

OBJECTIVE: To describe a broad range of physical disability by examining the association between a four-level measure of disability, based on self-report of difficulty in performing functional activities, and previously identified risk factors for disability. DESIGN: Cross-sectional. SETTING: Community-based. PARTICIPANTS: A total of 2373 noninstitutionalized men and women aged 65 and older from the Veneto Region of Italy. MEASUREMENTS: Odds ratios for the association of the four levels of disability (none, mild, moderate, and ADL disability) differentiated by this new measure with known risk factors for physical disability. MAIN RESULTS: This summary measure of physical disability distinguished older persons with disability from the population typically classified as nondisabled. Twenty-one percent of study participants were identified as having Activities of Daily Living (ADL) disability (defined as self-report of difficulty in one or more ADLs), and an additional 40% had mild or moderate disability based on degree of difficulty in Instrumental Activities of Daily Living (IADLs) and physical functional activities. Hip fracture and lower extremity performance were strongly independently associated with each level of disability. The association of a range of established risk factors for disability and health care utilization measures with the levels of disability identified in our study, and the trend toward increasing odds with increasing disability, provide evidence of the construct validity of this measure. CONCLUSIONS: Self-report of difficulty in performing functional activities identifies older persons with physical disability not ascertained by self-report of the need for help, the measure typically used to identify disability in older populations. Further studies should evaluate the potential for self-reported difficulty in functional activities to predict important disability-related outcomes.

Activities of Daily Living↗
PubMed1993

Regulation of c-kit expression in human myeloid cells.

In both murine and human systems the c-kit ligand, also known as mast cell growth factor (MGF), acts synergistically with several colony stimulating factors, including the granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin 3 (IL-3), in stimulating the proliferation and differentiation of different types of hematopoietic progenitors. In addition, MGF is also known to enhance the effects of GM-CSF and IL-3 on the in vitro proliferative activity of myeloid leukemic cells. MGF synergizes with a number of other cytokines such as GM-CSF, IL-3, IL-2, IL-4, IL-6 and IL-9 in sustaining the proliferation of growth factor dependent M-07e cells. In order to explore the molecular basis of this synergistic activity and to elucidate the regulatory mechanisms of c-kit expression, we investigated the effects of GM-CSF, IL-3 and MGF on c-kit mRNA and protein levels in M-07e cells. GM-CSF, unlike MGF and IL-3, induced a transient but significant increase of c-kit mRNA levels. Moreover, following MGF and GM-CSF treatment, c-kit protein expression in M-07e cells decreased, whereas all the other cytokines tested are unable to modulate c-kit protein. These data together with the results of protein turnover analysis suggest that MGF and GM-CSF regulate c-kit expression at the post-transcriptional level. In addition, the finding that IL-3 has no detectable effect on c-kit expression raises the possibility that GM-CSF-induced c-kit regulation is not mediated by the common signal transducing element: the beta subunit of the IL-3/GM-CSF receptor complex.

Gene Expression Regulation, Leukemic↗