341 research outputs found

    Performance of a large limited streamer tube cell in drift mode

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    The performance of a large (3x3 cm2cm^2) streamer tube cell in drift mode is shown. The detector space resolution has been studied using cosmic muons crossing an high precision silicon telescope. The experimental results are compared with a GARFIELD simulation.Comment: 18 pages, 7 figures. Accepted by Nucl. Instr. and Methods

    Misalignment factors to affect the fatigue of welded load-carrying joints

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    To assess the effects of misalignment on the weld fatigue, we present experimental fatigue test results of load- carrying cruciform joints which are subjected to axial variable amplitude loading. The welds were produced from steel AH36 grade and fatigue strength improved by high-frequently mechanical impact treatment. We identify several misalignment factors affecting the fatigue by considering the real and reference welded joint geometries. Our methodology includes proposals for the empirical calibration functions and local stress analyses by using the Structural Hot Spot Stress, Effective Notch Stress and Peak Stress Method. Additionally, we apply our methodology to other sixteen data sets which are extracted from the literature for load-carrying cruciform and butt welded joints subjected to constant amplitude loading. Finally, we present the resultant calibration functions with respect to corresponding fatigue test data

    High resolution pixel detectors for e+e- linear colliders

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    The physics goals at the future e+e- linear collider require high performance vertexing and impact parameter resolution. Two possible technologies for the vertex detector of an experimental apparatus are outlined in the paper: an evolution of the Hybrid Pixel Sensors already used in high energy physics experiments and a new detector concept based on the monolithic CMOS sensors.Comment: 8 pages, to appear on the Proceedings of the International Workshop on Linear Colliders LCWS99, Sitges (Spain), April 28 - May 5, 199

    The combined cartilage growth – calcification patterns in the wing-fins of Rajidae (Chondrichthyes): A divergent model from endochondral ossification of tetrapods

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    The relationship between cartilage growth – mineralization patterns were studied in adult Rajidae with X-ray morphology/morphometry, undecalcified resin-embedded, heat-deproteinated histology and scanning electron microscopy. Morphometry of the wing-fins, nine central rays of the youngest and oldest specimens documented a significant decrement of radials mean length between inner, middle and outer zones, but without a regular progression along the ray. This suggests that single radial length growth is regulated in such a way to align inter-radial joints parallel to the wing metapterygia curvature. Trans-illumination and heat-deproteination techniques showed polygonal and cylindrical morphotypes of tesserae, whose aligned pattern ranged from mono-columnar, bi-columnar, and multi-columnar up to the crustal-like layout. Histology of tessellated cartilage allowed to identify of zones of the incoming mineral deposition characterized by enhanced duplication rate of chondrocytes with the formation of isogenic groups, whose morphology and topography suggested a relationship with the impending formation of the radials calcified column. The morphotype and layout of radial tesserae were related to mechanical demands (stiffening) and the size/mass of the radial cartilage body. The cartilage calcification pattern of the batoids model shares several morphological features with tetrapods' endochondral ossification, that is, (chondrocytes' high duplication rate, alignment in rows, increased volume of chondrocyte lacunae), but without the typical geometry of the metaphyseal growth plates

    Circulating EGFL7 distinguishes between IUGR and PE: an observational case–control study

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    Isolated intrauterine growth restriction (IUGR) and preeclampsia (PE) share common placental pathogenesis. Differently from IUGR, PE is a systemic disorder which may also affect liver and brain. Early diagnosis of these conditions may optimize maternal and fetal management. Aim of this study was to assess whether Epidermal Growth Factor-Like domain 7 (EGFL7) dosage in maternal blood discriminates between isolated IUGR and PE. A total of 116 women were enrolled in this case-control study: 12 non-pregnant women, 34 healthy pregnant women, 34 women presenting with isolated IUGR and 36 presenting with PE. Levels of circulating EGFL7 and other known pro- and anti-angiogenic factors were measured by ELISA at different gestational ages (GA). Between 22-25 weeks of gestation, EGFL7 levels in early-onset PE (e-PE) plasma samples were significantly higher than those measured in controls or isolated IUGR samples (69.86 ± 6.17 vs. 19.8 ± 2.5 or 18.8 ± 2.8 Âµg/ml, respectively). Between 26-34 weeks, EGFL7 levels remained significantly higher in e-PE compared to IUGR. At term, circulating and placental EGFL7 levels were comparable between IUGR and late-onset PE (l-PE). In contrast, circulating levels of PlGF were decreased in both IUGR- and PE- complicated pregnancies, while levels of both sFLT-1 and sENDOGLIN were increased in both conditions. In conclusion, EGFL7 significantly discriminates between isolated IUGR and PE

    Human adipose-derived stromal cells transplantation prolongs reproductive lifespan on mouse models of mild and severe premature ovarian insufficiency

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    Background Although recent studies have investigated the ability of Mesenchymal Stromal Cells (MSCs) to alleviate short-term ovarian damage in animal models of chemotherapy-induced Premature Ovarian Insufficiency (POI), no data are available on reproductive lifespan recovery, especially in a severe POI condition. For this reason, we investigated the potential of MSCs isolated from human adipose tissue (hASCs), since they are easy to harvest and abundant, in ameliorating the length and performance of reproductive life in both mild and severe chemotherapy-induced murine POI models. Methods Mild and severe POI models were established by intraperitoneally administering a light (12 mg/kg busulfan + 120 mg/kg cyclophosphamide) or heavy (30 mg/kg busulfan + 120 mg/kg cyclophosphamide) dose of chemotherapy, respectively, in CD1 mice. In both cases, a week later, 1 × 106 hASCs were transplanted systemically through the tail vein. After four additional weeks, some females were sacrificed to collect ovaries for morphological evaluation. H&E staining was performed to assess stroma alteration and to count follicle numbers; immunofluorescence staining for αSMA was used to analyse vascularization. Of the remaining females, some were mated after superovulation to collect 2-cell embryos in order to evaluate their pre-implantation developmental capacity in vitro, while others were naturally mated to monitor litters and reproductive lifespan length. F1 litters’ weight, ovaries and reproductive lifespan were also analysed. Results hASC transplantation alleviated ovarian weight loss and size decrease and reduced alterations on ovarian stroma and vasculature, concurrently preventing the progressive follicle stockpile depletion caused by chemotherapy. These effects were associated with the preservation of the oocyte competence to develop into blastocyst in vitro and, more interestingly, with a significant decrease of chemotherapy-induced POI features, like shortness of reproductive lifespan, reduced number of litters and longer time to plug (the latter only presented in the severe POI model). Conclusion Human ASC transplantation was able to significantly reduce all the alterations induced by the chemotherapeutic treatment, while improving oocyte quality and prolonging reproductive functions, thus counteracting infertility. These results, strengthened by the use of an outbred model, support the potential applications of hASCs in women with POI, nowadays mainly induced by anticancer therapies

    Defects-related early childhood caries as hints of possible maternal–fetal health issues: Evidence from medieval northern Italy

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    Developmental defects of enamel (DDE) are important markers of stress as they arise from the disruption of ameloblastic activity during enamel matrix secretion and mineralization. Defects on the crowns of the deciduous dentition provide insights into maternal–fetal health because they can emerge during intrauterine development as a result of gestational issues. The presence of previous defective enamel represents one of the most predisposing causes of caries development. Thus, circular caries on the deciduous dentition are considered an indicator of stress because of their ascertained relation with dental enamel defects. In bioarchaeological analysis, these lesions allow us to deepen the question of maternal–fetal health issues in the ancient period. Here, we present evidence of defects-related early childhood caries in three infants from a medieval cemetery in northern Italy. The findings in the dentitions of the three subjects were investigated with a multi-analytical approach, including macroscopic examination, microscopic observation, cone-beam computed tomography (CBCT), scanning electron microscopy (SEM), and histological sections. In the specimens analyzed, the lesions observed in the dentitions appeared to have arisen during the fetal period and then protracted in the postnatal life, suggesting the implication of in utero environment and maternal health in the etiology of defects

    Occupational Exposure to Halogenated Anaesthetic Gases in Hospitals: A Systematic Review of Methods and Techniques to Assess Air Concentration Levels

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    Objective During the induction of gaseous anaesthesia, waste anaesthetic gases (WAGs) can be released into workplace air. Occupational exposure to high levels of halogenated WAGs may lead to adverse health effects; hence, it is important to measure WAGs concentration levels to perform risk assessment and for health protection purposes. Methods A systematic review of the scientific literature was conducted on two different scientific databases (Scopus and PubMed). A total of 101 studies, focused on sevoflurane, desflurane and isoflurane exposures in hospitals, were included in this review. Key information was extracted to provide (1) a description of the study designs (e.g., monitoring methods, investigated occupational settings, anaesthetic gases in use); (2) an evaluation of time trends in the measured concentrations of considered WAGs; (3) a critical evaluation of the sampling strategies, monitoring methods and instruments used. Results Environmental monitoring was prevalent (68%) and mainly used for occupational exposure assessment during adult anaesthesia (84% of cases). Real-time techniques such as photoacoustic spectroscopy and infrared spectrophotometry were used in 58% of the studies, while off-line approaches such as active or passive sampling followed by GC-MS analysis were used less frequently (39%). Conclusions The combination of different instrumental techniques allowing the collection of data with different time resolutions was quite scarce (3%) despite the fact that this would give the opportunity to obtain reliable data for testing the compliance with 8 h occupational exposure limit values and at the same time to evaluate short-term exposures

    Changes in Cardiac Autonomic Regulation after Acute Lung Exposure to Carbon Nanotubes: Implications for Occupational Exposure

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    Carbon nanotubes (CNTs) are among the most relevant engineered nanomaterials (ENMs). Given the expected rise of exposure to ENMs, there is concern that they may adversely affect health of exposed people. Aim of the study was to test the hypothesis that single wall carbon nanotubes (SWCNTs) pulmonary exposure acutely affect the autonomic cardiovascular regulation in conscious rats. We studied Wistar-Kyoto rats in which a telemetry transmitter for continuous arterial pressure (AP) and heart rate (HR) recordings was surgically implanted. SWCNTs dispersed in phosphate buffer saline (PBS) or PBS alone were randomly administered intratracheally. Immediately before, and 24 hours after each instillation a 30 min AP recording was performed. The sequence analysis was performed to evaluate the baroreflex function. In the control group, PBS instillation did not induce any significant changes. At variance the SWCNT exposure induced a significant reduction of baroreflex system (BRS) (3.5 \ub1 0.6 versus 2.6 \ub1 0.40\u2009msec/mmHg) without significant changes in the occurrence of baroreflex sequences (7.5 \ub1 0.47 % versus 7.4 \ub1 0.38 %). Our results show that SWCNT pulmonary exposure might affect the cardiovascular autonomic regulation thus contributing to cardiac and arrhythmic events

    A Survey on Continuous Time Computations

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    We provide an overview of theories of continuous time computation. These theories allow us to understand both the hardness of questions related to continuous time dynamical systems and the computational power of continuous time analog models. We survey the existing models, summarizing results, and point to relevant references in the literature
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