6,076 research outputs found

    Experimental investigation of the productivity of a wet separation process of traditional and bio-plastics

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    The separation process within a mechanical recycling plant plays a major role in the context of the production of high-quality secondary raw materials and the reduction of extensive waste disposal in landfills. Traditional plants for plastic separation employ dry or wet processes that rely on the different physical properties among the polymers. The hydraulic separator is a device employing a wet technology for particle separation. It allows the separation of two-polymer mixtures into two products, one collected within the instrument and the other one expelled through its outlet ducts. Apparatus performance were analyzed as a function of fluid and solid flow rates, flow patterns developing within the apparatus, in addition to the density, shape, and size of the polymers. For the hydraulic configurations tested, a two-way coupling takes place where the fluid exerts an influence on the plastic particles and the opposite occurs too. The interaction between the solid and liquid phases determines whether a certain polymer settles within the device or is expelled from the apparatus. Tests carried out with samples of increasing volumes of solid particles demonstrate that there are no significant differences in the apparatus effectiveness as far as a two-way interaction takes place. Almost pure concentrates of Polyethylene Terephthalate (PET), Polyvinyl Chloride (PVC), and Polycarbonate (PC) can be obtained from a mixture of traditional polymers. Tests conducted on Polylactic Acid (PLA) and Mater-Bi® samples showed that the hydraulic separator can be effectively employed to separate bio-plastics from conventional plastics with remarkable grade and recovery

    Intrauterine device use and risk of endometrial cancer.

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    The relationship between intrauterine device (IUD) use and risk of endometrial cancer has been analysed in a case-control study conducted in Italy between 1983 and 1992, including 453 patients with histologically confirmed endometrial cancer and 1,451 controls admitted for acute, non-gynaecological, non-hormonal, non-neoplastic conditions to the same network of hospitals where cases had been identified. Two (0.4%) cases versus 36 (2.3%) controls reported ever using an IUD. The corresponding multivariate relative risk was 0.4 (95% CI 0.1-1.0). The results of this study and the few published available epidemiological data suggest a protective role of IUD use on endometrial carcinogenesis, but potential selective mechanisms for IUD utilisation (indication bias) should be carefully considered in the interpretation

    Fluid-Dynamic Characterization and Efficiency Analysis in Plastic Separation of the Hydraulic Separator Multidune

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    Recovery of useable plastics from post-consumer and manufacturing waste remains a major recycling challenge. The global consumption of plastics was reported to be 230 million tonnes in 2005 of which 47.5 million tonnes were produced in Europe (25 European Union countries + Norway and Switzerland). Of the European production, only 22 million tonnes were reported as having been collected. Of this collected waste, 4 million tonnes were recycled as a manufacturing feedstock (18%) and 6.4 million tonnes went into energy recovery (29%), with the balance (11.6 million tonnes) probably being disposed in landfills. The recycling of plastics is a process essential to reduce the efflux of materials to landfills and to decrease the production of raw materials. In recent years awareness of the importance of environmental protection has led to the development of different techniques for plastic recycling. One issue related to the recycling of this material is the presence in the market of many types of plastics (polymers with additives), often with similar characteristics that make them difficult to differentiate in the recovery phase. The separator “Multidune” is a hydraulic separator by density. Its name derives from the characteristic undulate profile of the channel where separation occurs. The channel is constructed from a sequence of closed parallel cylindrical tubes welded together in plane which are then sliced down the lateral mid-plane and the lower complex is laterally shifted relative to the upper complex. The Multidune allows solid particle separation according to their specific weight and the velocity field establishing within the apparatus. Previous investigations suggested the flow within the Multidune is organized into three main patterns. Principally, a longitudinal transport flow takes place, where the velocity is high. A particle belonging to this region can move from one camera to another. The second region is the lower recirculation zone with high values of the vorticity field. Particles belonging to this region undergo the vertical impulse of the fluid. The thrust is proportional to the vertical velocity component and, in conjunction with gravity and buoyancy, determines the destiny of a particle. If the thrust is larger than the net weight of the particle, an interaction with the principal transport flow occurs and, consequently, the particle will move to the following chamber. The third region is the upper recirculation zone whose dimensions are smaller than the other recirculation zone. If a particle moves from the principal flow to the secondary vorticity zone, it will have the chance to come back to the previous chamber, assuming the principal transport flow thrust does not prevent it from falling out. Because of the role played by velocity, the fluid dynamic investigation of the Multidune apparatus is a preliminary step to carry out in order to investigate its capability in separating solid particles. For this reason a novel experimental campaign was set up and image analysis was employed to detect the velocity field within the apparatus

    PET and PVC separation with hyperspectral Imagery

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    Traditional plants for plastic separation in homogeneous products employ material physical properties (for instance density). Due to the small intervals of variability of different polymer properties, the output quality may not be adequate. Sensing technologies based on hyperspectral imaging have been introduced in order to classify materials and to increase the quality of recycled products, which have to comply with specific standards determined by industrial applications. This paper presents the results of the characterization of two different plastic polymers—polyethylene terephthalate (PET) and polyvinyl chloride (PVC)—in different phases of their life cycle (primary raw materials, urban and urban-assimilated waste and secondary raw materials) to show the contribution of hyperspectral sensors in the field of material recycling. This is accomplished via near-infrared (900–1700 nm) reflectance spectra extracted from hyperspectral images acquired with a two-linear-spectrometer apparatus. Results have shown that a rapid and reliable identification of PET and PVC can be achieved by using a simple two near-infrared wavelength operator coupled to an analysis of reflectance spectra. This resulted in 100% classification accuracy. A sensor based on this identification method appears suitable and inexpensive to build and provides the necessary speed and performance required by the recycling industry

    Risk factors for benign ovarian teratomas.

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    Risk factors for benign ovarian teratomas have been analysed in a case-control study conducted in Milan. Cases were women aged less than 65 years with a histologically confirmed diagnosis of benign ovarian teratoma who were admitted to a network of Obstetrics and Gynecology Departments in Milan. A total of 77 women aged 16-64 years were interviewed. Controls were women admitted to hospital for acute, non-gynaecological, non-hormonal and non-neoplastic diseases; 231 controls were interviewed (age range 15-64 years). Cases tended to be more educated: in comparison with women with less than 7 years of education, the estimated relative risk (RR) of ovarian benign teratoma was 1.6 and 2.5 respectively in women with 7-11 and 12 or more years of schooling, the trend in risk being statistically significant (chi 2(1) trend 5.39, P < 0.01). Four of the 77 cases (5.2%) and two of the 231 controls (0.9%) reported a history of infertility, with a corresponding RR of 8.3 (95% confidence interval 1.3-54.0). There was no clear relation between parity and risk of ovarian benign teratomas: in comparison with nulliparae, the estimated RRs were 1.1 and 0.7 respectively in women reporting one or two or more births (chi 2(1) trend 0.53, P = not significant). No relation emerged between marital status, age at menarche, menstrual cycle pattern, menopausal status, abortions, age at first pregnancy, oral contraceptive use and risk of ovarian benign teratomas

    A cohort study of the associations between udder conformation, milk somatic cell count, and lamb weight in suckler ewes

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    A cohort study of 67 suckler ewes from 1 farm was carried out from January to May 2010 to investigate associations between udder conformation, udder half milk somatic cell count (SCC), and lamb weight. Ewes and lambs were observed at lambing. Ewe health and teat condition and lamb health and weight were recorded on 4 to 5 further occasions at 14-d intervals. At each observation, a milk sample was collected from each udder half for somatic cell counting. Two weeks after lambing, ewe udder conformation and teat placement were scored. Low lamb weight was associated with ewe SCC >400,000 cells/mL (−0.73kg), a new teat lesion 14 d previously (−0.91kg), suboptimal teat position (−1.38kg), rearing in a multiple litter (−1.45kg), presence of diarrhea at the examination (−1.19kg), and rearing by a 9-yr-old ewe compared with a 6-yr-old ewe (−2.36kg). High lamb weight was associated with increasing lamb age (0.21kg/d), increasing birth weight (1.65kg/kg at birth), and increasing number of days the ewe was given supplementary feed before lambing (0.06kg/d). High udder half SCC was associated with pendulous udders (9.6% increase in SCC/cm of drop) and greater total cross-sectional area of the teats (7.2% increase of SCC/cm2). Low SCC were associated with a heavier mean litter weight (6.7% decrease in SCC/kg). Linear, quadratic, and cubic terms for days in lactation were also significant. We conclude that poor udder and teat conformation are associated with high levels of intramammary infection, as indicated by increased SCC and that both physical attributes of the udder and SCC are linked to lamb growth, suggesting that selection of suckler ewes with better udder and teat conformation would reduce intramammary infection and increase lamb growth rate

    Prevalencia de helicobacter pylori en pacientes con gingivitis y enfermedad peridontal

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    With the objetive of detennine the helicobacter pylori (Hp) prevsalencv in patiens with gingivitis and periodontal disease, it was collected and processed sullgingival plate samples from 177 patients whose have been classffied according to: 1) Ulcer and gingivitis, 2) gastritis and gingivitis, 3) gingivitis and 4) periodontitis aleatoriamente selected at the Odontological Clinic! of San Marcos University It was recovered Hp in 9,4%ftom the studied poblation, tnoreftecuenilly in women (6,8%) than in men (2,6 %). Helicobacerpylori was recovered.front the 7,7 % qfpatients with giligivitis, and from the 1,7% of patients with gastritis and gingivitis. Principally Hp was recovered neither from patients with ulcer and gingivitis nor patienty with periodontitis. principally Hp was recovered form people between 20 and 30 years old, and more frecuently in womwn than in men.Con el objetivo de determinar la prevalecencia de helicobacter pylori (Hp) en pacientes con gingivitis y enfermedad periodontal, se colectó y procesó muestras de placa subgingival de 117 pacientes categorizados según los siguientes antecedentes registrados: 1) úlcera gingivitis, 2)gastritis v gingivitis, 3) gingivitis y 4) periodontitis, aleatoriamente seleccionados en la Clínica a Odontológica de la Universidad de San Marcos. Se recupero Hp en 9,4% de la población en estudio, más frecuentemente en mujeres (6,8%) que en hombres (2,6%). Helicobacter pylori se recupero en el 7,7 % de pacientes con gingivitis, y en el 1, 7 % de pacientes con gastritis y gingivitis. No se recuperó de pacientes con úlcera y gingivitis, ni de pacientes con periodontitis. Hp se recuperó mayormente en los estratos Ile 20 a 30 afios, y más frecuente en mujeres que hombres

    Butterflies as bioindicators of metal contamination

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    Anthropogenic trace metal contamination has significantly increased and has caused many hazardous consequences for the ecosystems and human health. The Terni basin valley (Central Italy) shows a heavy load of pollutants from industrial activities, while the characteristic orography structure of the valley favours air stagnation, thus limiting air pollution dispersal. The present study conducted in 2014 aimed to determine the concentration of ten metals in five species of butterflies at nine sites in the Terni valley along a 21-km-long transect, including both relatively pristine and industrial areas. At sites where soil contamination was high for a given metal, such as for chromium as in the case of site 4 (the closest to the steel plant) and for lead as in the case of site 2 (contaminated by a firing range), higher levels of contamination were observed in the tissues of butterflies. We found a correlation between soil contamination and the concentration of Cr, Al and Sr in the tissues of some species of butterflies. The sensitivity to contamination differed among the five species; in particular, Coenonympha pamphilus was generally the species that revealed the highest concentrations of all the ten trace metals at the sites closer to the industrial area. It is known that C. pamphilus is a sedentary species and that its host plants are the Poaceae, capable of accumulating high quantities of metals in their rhizosphere region, thus providing the link with soil contamination. Therefore, monitoring the metal concentration levels in butterflies might be a good indicator and a control tool of environmental quality, specifically in areas affected by high anthropogenic pollution loads linked to a specific source

    From bi-layer to tri-layer Fe nanoislands on Cu3Au(001)

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    Self assembly on suitably chosen substrates is a well exploited root to control the structure and morphology, hence magnetization, of metal films. In particular, the Cu3Au(001) surface has been recently singled out as a good template to grow high spin Fe phases, due to the close matching between the Cu3Au lattice constant (3.75 Angstrom) and the equilibrium lattice constant for fcc ferromagnetic Fe (3.65 Angstrom). Growth proceeds almost layer by layer at room temperature, with a small amount of Au segregation in the early stage of deposition. Islands of 1-2 nm lateral size and double layer height are formed when 1 monolayer of Fe is deposited on Cu3Au(001) at low temperature. We used the PhotoElectron Diffraction technique to investigate the atomic structure and chemical composition of these nanoislands just after the deposition at 140 K and after annealing at 400 K. We show that only bi-layer islands are formed at low temperature, without any surface segregation. After annealing, the Fe atoms are re-aggregated to form mainly tri-layer islands. Surface segregation is shown to be inhibited also after the annealing process. The implications for the film magnetic properties and the growth model are discussed.Comment: Revtex, 5 pages with 4 eps figure

    FISSIT (Fistula Surgery in Italy) study: A retrospective survey on the surgical management of anal fistulas in Italy over the last 15 years

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    Background: Surgical treatment of anal fistulas is still a challenge. The aims of this study were to evaluate the adoption and healing rates for the different surgical techniques used in Italy over the past 15 years. Methods: This was a multicenter retrospective observational study of patients affected by simple and complex anal fistulas of cryptoglandular origin who were surgically treated in the period 2003-2017. Surgical techniques were grouped as sphincter-cutting or sphincter-sparing and as technology-assisted or techno-free. All patients included in the study were followed for at least 12 months. Results: A total of 9,536 patients (5,520 simple; 4,016 complex fistulas) entered the study. For simple fistulas, fistulotomy was the most frequently used procedure, although its adoption significantly decreased over the years (P &lt; .0005), with an increase in sphincter-sparing approaches; the overall healing rate in simple fistulas was 81.1%, with a significant difference between sphincter-cutting (91.9%) and sphincter-sparing (65.1%) techniques (P = .001). For complex fistulas, the adoption of sphincter-cutting approaches decreased, while sphincter-sparing techniques were mildly preferred (P &lt; .0005). Moreover, there was a significant trend toward the use of technology-assisted procedures. The overall healing rate for complex fistulas was 69.0%, with a measurable difference between sphincter-cutting (81.1%) and sphincter-sparing (61.4%; P = .001) techniques and between techno-free and technology-assisted techniques (72.5% and 55.0%, respectively; P = .001). Conclusion: Surgical treatment of anal fistulas has changed, with a trend toward the use of sphincter-sparing techniques. The overall cure rate has remained stable, even if the most innovative procedures have achieved a lower success rate
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