1,005 research outputs found

    Piezoelectric effect and electroactive phase nucleation in self-standing films of unpoled PVDF nanocomposite films

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    Novel polymer-based piezoelectric nanocomposites with enhanced electromechanical properties open new opportunities for the development of wearable energy harvesters and sensors. This paper investigates how the dissolution of different types of hexahydrate metal salts affects β-phase content and piezoelectric response (d33) at nano-and macroscales of polyvinylidene fluoride (PVDF) nanocomposite films. The strongest enhancement of the piezoresponse is observed in PVDF nanocomposites processed with Mg(NO3)2·6H2O. The increased piezoresponse is attributed to the synergistic effect of the dipole moment associated with the nucleation of the electroactive phase and with the electrostatic interaction between the CF2group of PVDF and the dissolved salt through hydrogen bonding. The combination of nanofillers like graphene nanoplatelets or zinc oxide nanorods with the hexahydrate salt dissolution in PVDF results in a dramatic reduction of d33, because the nanofiller assumes a competitive role with respect to H-bond formation between PVDF and the dissolved metal salt. The measured peak value of d33reaches the local value of 13.49 pm/V, with an average of 8.88 pm/V over an area of 1 cm2. The proposed selection of metal salt enables low-cost production of piezoelectric PVDF nanocomposite films, without electrical poling or mechanical stretching, offering new opportunities for the development of devices for energy harvesting and wearable sensors

    The association between overweight and illegal drug consumption in adolescents is there an underlying influence of the sociocultural environment?

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    Background: The aims of the study were to: a) Examine the distribution of gender-stratified body mass index (BMI), eating attitudes and use of addictive substances, under the hypothesis of a confluent prevalence of weight abnormalities, eating disorders and substance abuse. b) Demonstrate the extent to which family, peer-related and psychosocial factors are common elements in categories of compulsive behaviour. Methodology/Principal Findings: In the present cross-sectional study, data were collected through self reported questionnaires administered to a large sample of 33,185 15-19 years old adolescents (ESPADHItalia), divided into weight categories based on the BMI percentile distribution. Multinomial analyses were adopted to address the influence of social, family, leisure time factors, Eating Attitude Test (EAT26) on the association between weight categories and drug use. Recent drugs use was more frequent in overweight and underweight adolescents (p,0.05), especially in females. An EAT26 score $20 was more common in overweight adolescents. Multinomial analysis abolished the relationship between overweight and the use of most drugs, implicating self-esteem, parents\u27 educational level, and friendships as mediators of the association. Within the overweight category, adolescents reporting recent drug use, showed greater frequency of having drug-abusing friends (,80%), and severe problems with parents and school (,30%) compared to overweight adolescents without recent drug use. Conclusion: The frequent association of overweight and substance use and the presence of common underlying social factors, highlights the need for an interdisciplinary approach involving individual-focused treatment models as well as public health, social and environmental changes to reduce food- and substances-related problems.

    Ancient DNA: genomic amplification of Roman and medieval bovine bones.

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    Cattle remains (bones and teeth) of both roman and medieval age were collected in the archaeological site of Ferento (Viterbo, Italy) with the aim of extracting and characterising nucleic acids. Procedures to minimize contamination with modern DNA and to help ancient DNA (aDNA) preservation of the archaeological remains were adopted. Different techniques to extract aDNA (like Phenol/chloroform extraction) from bovine bones were tested to identify the method that applies to the peculiar characteristics of the study site. Currently, aDNA investigation is mainly based on mtDNA, due to the ease of amplification of the small and high-copied genome and to its usefulness in evolutionary studies. Preliminary amplification of both mitochondrial and nuclear aDNA fragments from samples of Roman and medieval animals were performed and partial specific sequences of mitochondrial D-loop as well as of nuclear genes were obtained. The innovative amplification of nuclear aDNA could enable the analysis of genes involved in specific animal traits, giving insights of ancient economic and cultural uses, as well as providing information on the origin of modern livestock population

    Italian Report: EMCDDA Project (CC.09.EPI.002)

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    Although there are definitions and diagnostic criteria to identify cannabis abuse and dependence, there is no a shared concept of cannabis use related problems. In recent times a number of indicators have been discussed and implemented (use severity and consumption patterns, treatment demands etc) and there are different screening instruments used to measure negative consequences of cannabis use. Short screening scales to assess dependence and other problems related to the use of cannabis seem to be usefull instruments, easy to be administered, to estimate prevalence of cannabis related negative consequences and to identify at risk-persons. The need to standardize also in Italy a set of instruments which allow to monitor problematic cannabis use patterns or addiction development, has been highlighted. The three scales Cannabis Abuse Screening Test (CAST), Severity of Dependence Scale (SDS) and Munich Composite International Diagnostic Interview (M-CIDI) are included in the questionnaire used in ESPAD-Italia? 2009 survey. The present work considers the validation process of these instruments in high school population.not availabl

    A non-invasive approach to monitor chronic lymphocytic leukemia engraftment in a xenograft mouse model using ultra-small superparamagnetic iron oxide-magnetic resonance imaging (USPIO-MRI).

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    This work was supported by: Associazione Italiana Ricerca sul Cancro (AIRC) [Grant 5 x mille n.9980, (to M.F., F.M. and A. N.)]; AIRC I.G. [n. 14,326 (to M.F.)], [n.10136 and 16,722 (A.N.)], [n.15426 (to F.F.)]. AIRC and Fondazione CaRiCal co-financed Multi Unit Regional Grant 2014 [n.16695 (to F.M.)]. Italian Ministry of Health 5 × 1000 funds (to F.F). A.G R. was supported by Associazione Italiana contro le Leucemie-Linfomi-Mielomi (AIL) Cosenza - Fondazione Amelia Scorza (FAS). S.M. C.M., F.V., L. E., S. B., were supported by AIRC.Peer reviewedPostprin

    Celiac disease and obstetric complications: a systematic review and metaanalysis

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    The aim of this metaanalysis was to evaluate the risk of the development of obstetric complications in women with celiac disease. We searched electronic databases from their inception until February 2015. We included all cohort studies that reported the incidence of obstetric complications in women with celiac disease compared with women without celiac disease (ie, control group). Studies without a control group and case-control studies were excluded. The primary outcome was defined a priori and was the incidence of a composite of obstetric complications that included intrauterine growth restriction, small for gestational age, low birthweight, preeclampsia and preterm birth. Secondary outcomes included the incidence of preterm birth, intrauterine growth restriction, stillbirth, preeclampsia, small for gestational age, and low birthweight. The review was registered with PROSPERO (CRD42015017263) before data extraction. All authors were contacted to obtain the original databases and perform individual participant data metaanalysis. Primary and secondary outcomes were assessed in the aggregate data analysis and in the individual participant data metaanalysis. We included 10 cohort studies (4,844,555 women) in this metaanalysis. Four authors provided the entire databases for the individual participant data analysis. Because none of the included studies stratified data for the primary outcome (ie, composite outcome), the assessment of this outcome for the aggregate analysis was not feasible. Aggregate data analysis showed that, compared with women in the control group, women with celiac disease (both treated and untreated) had a significantly higher risk of the development of preterm birth (adjusted odds ratio, 1.35; 95% confidence interval, 1.09-1.66), intrauterine growth restriction (odds ratio, 2.48; 95% confidence interval, 1.32-4.67), stillbirth (odds ratio, 4.84; 95% confidence interval, 1.08-21.75), low birthweight (odds ratio, 1.63; 95% confidence interval, 1.06-2.51), and small for gestational age (odds ratio, 4.52; 95% confidence interval, 1.02-20.08); no statistically significant difference was found in the incidence of preeclampsia (odds ratio, 2.45; 95% confidence interval, 0.90-6.70). The risk of preterm birth was still significantly higher both in the subgroup analysis of only women with diagnosed and treated celiac disease (odds ratio, 1.26; 95% confidence interval, 1.06-1.48) and in the subgroup analysis of only women with undiagnosed and untreated celiac disease (odds ratio, 2.50; 95% confidence interval; 1.06-5.87). Women with diagnosed and treated celiac disease had a significantly lower risk of the development of preterm birth, compared with undiagnosed and untreated celiac disease (odds ratio, 0.80; 95% confidence interval, 0.64-0.99). The individual participant data metaanalysis showed that women with celiac disease had a significantly higher risk of composite obstetric complications compared with control subjects (odds ratio, 1.51; 95% confidence interval, 1.17-1.94). Our individual participant data concurs with the aggregate analysis for all the secondary outcomes. In summary, women with celiac disease had a significantly higher risk of the development of obstetric complications that included preterm birth, intrauterine growth restriction, stillbirth, low birthweight, and small for gestational age

    High-dimensional and one-class classification

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    When dealing with high-dimensional data and, in particular, when the number of attributes p is large comparatively to the sample size n, several classification methods cannot be applied. Fisher's linear discriminant rule or the quadratic discriminant one are unfeasible, as the inverse of the involved covariance matrices cannot be computed. A recent approach to overcome this problem is based on Random Projections (RPs), which have emerged as a powerful method for dimensionality reduction. In 2017, Cannings and Samworth introduced the RP method in the ensemble context to extend to the high-dimensional domain classification methods originally designed for low-dimensional data. Although the RP ensemble classifier allows improving classification accuracy, it may still include redundant information. Moreover, differently from other ensemble classifiers (e.g. Random Forest), it does not provide any insight on the actual classification importance of the input features. To account for these aspects, in the first part of this thesis, we investigate two new directions of the RP ensemble classifier. Firstly, combining the original idea of using the Multiplicative Binomial distribution as the reference model to describe and predict the ensemble accuracy and an important result on such distribution, we introduce a stepwise strategy for post-pruning (called Ensemble Selection Algorithm). Secondly, we propose a criterion (called Variable Importance in Projection) that uses the feature coefficients in the best discriminant projections to measure the variable importance in classification. In the second part, we faced the new challenges posed by the high-dimensional data in a recently emerging classification context: one-class classification. This is a special classification task, where only one class is fully known (the target class), while the information on the others is completely missing. In particular, we address this task by using Gini's transvariation probability as a measure of typicality, aimed at identifying the best boundary around the target class
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