388 research outputs found

    Molecular imprinting on surface of silica particles for the selective extraction of benzylparaben in flow system applied to cosmetics and water samples

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    Molecular imprinted polymer coated Silica (Si-MIP) particles were prepared using non-covalent approach. The Si-MIP material was employed as selective solid phase extraction sorbent for the determination of benzylparaben (BP) in samples of environmental and cosmetic origin. The preconcentration step was studied firstly in a batch system and subsequently it was optimized and adapted to an automatized flow system and the eluate was then analyzed by HPLC-UV. The whole procedure was validated, showing satisfactory analytical parameters. The methodology was applied to real samples showing extraction recoveries always better than 98.85%. A linear response within the concentration range of 1.11 × 10−5–0.025 mg mL−1 was obtained for BP (r2 = 0.9998). The limits of detection and quantification after Si-MIP-HPLC procedure were 3.34 and 11.16 ng mL−1, respectively. The developed methodology provided a simple an economic way for accomplishing a clean-up/preconcentration step and the subsequent determination of BP in a complex matrix. The showed selectivity plus robustness and the possibility of reutilization, enable it to be used for BP routine monitoring in personal care products (PCP) and environmental samples.Fil: Vicario, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Solari, Victor Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina; ArgentinaFil: Felici, Carlos Emiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina; ArgentinaFil: Aragón, Leslie. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Farmacia; ArgentinaFil: Bertolino, Franco Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina; ArgentinaFil: Gomez, Maria Roxana Anabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina; Argentin

    The Key Role of Memory in Next-Generation Embedded Systems for Military Applications

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    With the increasing use of multi-core platforms in safety-related domains, aircraft system integrators and authorities exhibit a concern about the impact of concurrent access to shared-resources in the Worst-Case Execution Time (WCET). This paper highlights the need for accurate memory-centric scheduling mechanisms for guaranteeing prioritized memory accesses to Real-Time safety-related components of the system. We implemented a software technique called cache coloring that demonstrates that isolation at timing and spatial level can be achieved by managing the lines that can be evicted in the cache. In order to show the effectiveness of this technique, the timing properties of a real application are considered as a use case, this application is made of parallel tasks that show different trade-offs between computation and memory loads

    Selection, affinity maturation, and characterization of a human scFv antibody against CEA protein

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    BACKGROUND: CEA is a tumor-associated antigen abundantly expressed on several cancer types, including those naturally refractory to chemotherapy. The selection and characterization of human anti-CEA single-chain antibody fragments (scFv) is a first step toward the construction of new anticancer monoclonal antibodies designed for optimal blood clearance and tumor penetration. METHODS: The human MA39 scFv, selected for its ability to recognize a CEA epitope expressed on human colon carcinomas, was first isolated from a large semi-synthetic ETH-2 antibody phage library, panned on human purified CEA protein. Subsequently, by in vitro mutagenesis of a gene encoding for the scFv MA39, a new library was established, and new scFv antibodies with improved affinity towards the CEA cognate epitope were selected and characterized. RESULTS: The scFv MA39 antibody was affinity-maturated by in vitro mutagenesis and the new scFv clone, E8, was isolated, typed for CEA family member recognition and its CEACAM1, 3 and 5 shared epitope characterized for expression in a large panel of human normal and tumor tissues and cells. CONCLUSION: The binding affinity of the scFv E8 is in a range for efficient, in vivo, antigen capture in tumor cells expressing a shared epitope of the CEACAM1, 3 and 5 proteins. This new immunoreagent meets all criteria for a potential anticancer compound: it is human, hence poorly or not at all immunogenic, and it binds selectively and with good affinity to the CEA epitope expressed by metastatic melanoma and colon and lung carcinomas. Furthermore, its small molecular size should provide for efficient tissue penetration, yet give rapid plasma clearance

    Selection of Mimotopes of the Cell Surface Adhesion Molecule Mel-CAM from a Random pVIII-28aa Phage Peptide Library

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    The cell surface adhesion molecule Mel-CAM is highly expressed in advanced primary and metastatic melanoma. Mel-CAM was first described as an integral membrane glycoprotein of malignant melanoma cells. The murine monoclonal antibody MAd18-5D7 recognizes an epitope of the extracellular domain of Mel-CAM and is able to enhance Mel-CAM mediated adhesion of melanoma cells in aggregation assays. For the characterization of peptides that antigenically mimic surface-exposed areas of Mel-CAM we screened a newly constructed random pVIII-28aa bacteriophage peptide library against MAd18-5D7. After three panning rounds a population of phages binding to MAd18-5D7 was enriched. Peptides expressed on the surface of these phages were then tested for their specificity for the antibody's antigen binding site. DNA sequences coding for two specific peptide ligands were determined. One of the deduced amino acid sequences showed similarity to a portion of the sequence of the third immunoglobulin-like extracellular domain of Mel-CAM. Both peptides blocked the interaction of MAd18-5D7 with Mel-CAM present in a MelJuSo melanoma cell line lysate. Phage displayed as well as synthetic peptides inhibited in a dose-dependent manner the binding of MAd18-5D7 to recombinant Mel-CAM in enzyme-linked immunosorbent assay experiments. No such inhibition was observed using a panel of other anti-Mel-CAM antibodies. Our results clearly indicate that these 28mer peptides are structural equivalents of the MAd18-5D7 epitope of Mel-CAM and that they will be useful tools for further in vitro and in vivo studies of Mel-CAM mediated cell–cell interaction

    Protective Activity of Streptococcus pneumoniae Spr1875 Protein Fragments Identified Using a Phage Displayed Genomic Library

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    There is considerable interest in pneumococcal protein antigens capable of inducing serotype-independent immunoprotection and of improving, thereby, existing vaccines. We report here on the immunogenic properties of a novel surface antigen encoded by ORF spr1875 in the R6 strain genome. An antigenic fragment encoded by spr1875, designated R4, was identified using a Streptococcus pneumoniae phage displayed genomic library after selection with a human convalescent serum. Immunofluorescence analysis with anti-R4 antisera showed that Spr1875 was expressed on the surface of strains belonging to different serotypes. Moreover, the gene was present with little sequence variability in 27 different pneumococcal strains isolated worldwide. A mutant lacking Spr1875 was considerably less virulent than the wild type D39 strain in an intravenous mouse model of infection. Moreover, immunization with the R4 recombinant fragment, but not with the whole Spr1875 protein, induced significant protection against sepsis in mice. Lack of protection after immunization with the whole protein was related to the presence of immunodominant, non-protective epitopes located outside of the R4 fragment. In conclusion, our data indicate that Spr1875 has a role in pneumococcal virulence and is immunogenic. As the R4 fragment conferred immunoprotection from experimental sepsis, selected antigenic fragments of Spr1875 may be useful for the development of a pneumococcal protein-based vaccine

    Efficacy and safety of growth hormone treatment in children with short stature: the Italian cohort of the GeNeSIS clinical study

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    Purpose: We examined auxological changes in growth hormone (GH)-treated children in Italy using data from the Italian cohort of the multinational observational Genetics and Neuroendocrinology of Short Stature International Study (GeNeSIS) of pediatric patients requiring GH treatment. Methods: We studied 711 children (median baseline age 9.6 years). Diagnosis associated with short stature was as determined by the investigator. Height standard deviation score (SDS) was evaluated yearly until final or near-final height (n = 78). Adverse events were assessed in all GH-treated patients. Results: The diagnosis resulting in GH treatment was GH deficiency (GHD) in 85.5 % of patients, followed by Turner syndrome (TS 6.6 %). Median starting GH dose was higher in patients with TS (0.30 mg/kg/week) than patients with GHD (0.23 mg/kg/week). Median (interquartile range) GH treatment duration was 2.6 (0.6\u20133.7) years. Mean (95 % confidence interval) final height SDS gain was 2.00 (1.27\u20132.73) for patients with organic GHD (n = 18) and 1.19 (0.97\u20131.40) for patients with idiopathic GHD (n = 41), but lower for patients with TS, 0.37 ( 120.03 to 0.77, n = 13). Final height SDS was > 122 for 94 % of organic GHD, 88 % of idiopathic GHD and 62 % of TS patients. Mean age at GH start was lower for organic GHD patients, and treatment duration was longer than for other groups, resulting in greater mean final height gain. GH-related adverse events occurred mainly in patients diagnosed with idiopathic GHD. Conclusions: Data from the Italian cohort of GeNeSIS showed auxological changes and safety of GH therapy consistent with results from international surveillance databases

    Trapping in irradiated p-on-n silicon sensors at fluences anticipated at the HL-LHC outer tracker

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    The degradation of signal in silicon sensors is studied under conditions expected at the CERN High-Luminosity LHC. 200 μ\mum thick n-type silicon sensors are irradiated with protons of different energies to fluences of up to 3⋅10153 \cdot 10^{15} neq/cm2^2. Pulsed red laser light with a wavelength of 672 nm is used to generate electron-hole pairs in the sensors. The induced signals are used to determine the charge collection efficiencies separately for electrons and holes drifting through the sensor. The effective trapping rates are extracted by comparing the results to simulation. The electric field is simulated using Synopsys device simulation assuming two effective defects. The generation and drift of charge carriers are simulated in an independent simulation based on PixelAV. The effective trapping rates are determined from the measured charge collection efficiencies and the simulated and measured time-resolved current pulses are compared. The effective trapping rates determined for both electrons and holes are about 50% smaller than those obtained using standard extrapolations of studies at low fluences and suggests an improved tracker performance over initial expectations
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