411 research outputs found

    Formalism for obtaining nuclear momentum distributions by the Deep Inelastic Neutron Scattering technique

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    We present a new formalism to obtain momentum distributions in condensed matter from Neutron Compton Profiles measured by the Deep Inelastic Neutron Scattering technique. The formalism describes exactly the Neutron Compton Profiles as an integral in the momentum variable yy. As a result we obtain a Volterra equation of the first kind that relates the experimentally measured magnitude with the momentum distributions of the nuclei in the sample. The integration kernel is related with the incident neutron spectrum, the total cross section of the filter analyzer and the detectors efficiency function. A comparison of the present formalism with the customarily employed approximation based on a convolution of the momentum distribution with a resolution function is presented. We describe the inaccuracies that the use of this approximation produces, and propose a new data treatment procedure based on the present formalism.Comment: 11 pages, 8 figure

    Prognostic role of pneumonia in supracricoid and supraglottic laryngectomies.

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    The goal of this study was to identify host and tumour factors associated with postoperative pneumonia (PP) in a selected population of laryngeal cancer patients, treated by partial laryngectomy in 20 years at our Institution and to assess its potential prognostic impact. Clinical records of 416 consecutive patients were retrospectively reviewed. Tobacco consumption, body mass index (BMI), previous pulmonary disease, age, sex, preoperative blood gas analysis values, tumour stage and type of surgery were tested as potential risk factors for PP. Finally, the prognostic impact of these variables, including PP, in terms of disease-free and actuarial survival by Kaplan-Meier and Cox analyses were evaluated. PP developed in 73 patients (16.8\%). We identified two groups of patients: 26 patients experienced an early PP within the first 7-9 days after surgery, whilst 44 experienced an ab ingestis PP following attempts of oral food intake restoration, three patients died for PP related sepsis. At multivariate Cox analysis, age older than 60 years and BMI greater than 30 were statistically associated with early PP; whereas male gender and laryngectomy with neck dissection were statistically related to a higher risk of ab ingestis PP. Interestingly, the occurrence of early PP was a negative independent prognostic factor for 5-years disease-free and actuarial survival (p=0.049 and p=0.001, respectively). The occurrence of early-onset pneumonia in laryngeal cancer patients selected for conservative laryngectomies is predictable and associated with poor clinical outcome

    Semiquantitative analysis of mercury in landfill leachates using double-pulse laser-induced breakdown spectroscopy.

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    Made available in DSpace on 2017-11-02T09:09:43Z (GMT). No. of bitstreams: 1 PROCI17Semiquantitativeanalysisofmercury....pdf: 746927 bytes, checksum: b75c0ae6928400c1c1207ac3be058399 (MD5) Previous issue date: 2017-10-31bitstream/item/165918/1/PROCI-17-Semiquantitative-analysis-of-mercury....pd

    Epitaxial Growth of DNA-Assembled Nanoparticle Superlattices on Patterned Substrates

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    DNA-functionalized nanoparticles, including plasmonic nanoparticles, can be assembled into a wide range of crystalline arrays via synthetically programmable DNA hybridization interactions. Here we demonstrate that such assemblies can be grown epitaxially on lithographically patterned templates, eliminating grain boundaries and enabling fine control over orientation and size of assemblies up to thousands of square micrometers. We also demonstrate that this epitaxial growth allows for orientational control, systematic introduction of strain, and designed defects, which extend the range of structures that can be made using superlattice assembly. Ultimately, this will open the door to integrating self-assembled plasmonic nanoparticle materials into on-chip optical or optoelectronic platforms

    Neutron-enhanced information on the laboratory characterization of ancient Egyptian leathers: hydration and preservation status

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    The Museo Egizio’s collection contains 200 precious and unique leather artifacts belonging to different historical periods. The materials used during the tanning and curing procedures affect the chemical and elemental composition of the surface of the samples as well as their preservation status, specifically through the hydration level within the bulk. Here we provide an experimental characterization of a series of samples from Museo Egizio that document an extensive denaturation phenomenon (gelatinization), by combining non-destructive techniques including surface probes (X-ray fluorescence, Raman scattering, and scanning electron microscopy enhanced by X-ray energy spectroscopy) and neutron-based bulk techniques (inelastic and deep-inelastic neutron scattering). Results show partial dehydration of the samples in the bulk, affecting the morphology of their surface, the presence of potassium alum, and iron oxides, as well as phosphates and hydroxides related to the tanning and curing procedures. Finally, we briefly discuss the need for a versatile and adaptable software package that is capable of combining quantitative analyses with complementary techniques including morphological, elemental, and chemical composition

    Cross-linking cellular prion protein induces neuronal type 2-like hypersensitivity

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    Background: Previous reports identified proteins associated with ‘apoptosis’ following cross-linking PrPC with motif-specific anti-PrP antibodies in vivo and in vitro. The molecular mechanisms underlying this IgG-mediated neurotoxicity and the role of the activated proteins in the apoptotic pathways leading to neuronal death has not been properly defined. Previous reports implicated a number of proteins, including apolipoprotein E, cytoplasmic phospholipase A2, prostaglandin and calpain with antiPrP antibody-mediated ‘apoptosis’, however, these proteins are also known to play an important role in allergy. In this study, we investigated whether cross-linking PrPC with anti-PrP antibodies stimulates a neuronal allergenic response. Methods: Initially, we predicted the allergenicity of the epitope sequences associated with ‘neurotoxic’ anti-PrP antibodies using allergenicity prediction servers. We then investigated whether anti-PrP antibody treatment of mouse primary neurons (MPN), neuroblastoma cells (N2a) and microglia (N11) cell lines lead to a neuronal allergenic response. Results: In-Silico studies showed that both tail- and globular-epitopes were allergenic. Specifically, binding regions that contain epitopes for previously reported ‘neurotoxic’ antibodies such as ICSM18 (146-159), ICSM35 (91-110), POM 1 (138-147) and POM 3 (95-100) lead to activation of allergenic related proteins. Following direct application of antiPrPC antibodies on N2a cells, we identified 4 neuronal allergenic-related proteins when compared with untreated cells. Furthermore, we identified 8 neuronal allergenic-related proteins following treatment of N11 cells with anti-PrPC antibodies prior to co-culture with N2a cells when compared with untreated cells. Antibody treatment of MPN or MPN co-cultured with antibody-treated N11 led to identifying 10 and 7 allergenic-related proteins when compared with untreated cells. However, comparison with 3F4 antibody treatment revealed 5 and 4 allergenic-related proteins respectively. Of importance, we showed that the allergenic effects triggered by the anti-PrP antibodies were more potent when antibody-treated microglia were co-cultured with the neuroblastoma cell line. Finally, co-culture of N2a or MPN with N11-treated with anti-PrP antibodies resulted in significant accumulation of NO and IL6 but not TNF-a in the cell culture media supernatant. Conclusions: This study showed for the first time that anti-PrP antibody binding to PrPC triggers a neuronal hypersensitivity response and highlights the important role of microglia in triggering an IgG-mediated neuronal hypersensitivity response. Moreover, this study provides an important impetus for including allergenic assessment of therapeutic antibodies for neurodegenerative disorders to derive safe and targeted biotherapeutics

    Behavior and Impact of Zirconium in the Soil–Plant System: Plant Uptake and Phytotoxicity

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    Because of the large number of sites they pollute, toxic metals that contaminate terrestrial ecosystems are increasingly of environmental and sanitary concern (Uzu et al. 2010, 2011; Shahid et al. 2011a, b, 2012a). Among such metals is zirconium (Zr), which has the atomic number 40 and is a transition metal that resembles titanium in physical and chemical properties (Zaccone et al. 2008). Zr is widely used in many chemical industry processes and in nuclear reactors (Sandoval et al. 2011; Kamal et al. 2011), owing to its useful properties like hardness, corrosion-resistance and permeable to neutrons (Mushtaq 2012). Hence, the recent increased use of Zr by industry, and the occurrence of the Chernobyl and Fukashima catastrophe have enhanced environmental levels in soil and waters (Yirchenko and Agapkina 1993; Mosulishvili et al. 1994 ; Kruglov et al. 1996)
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