560 research outputs found

    A novel method to titrate Herpes simplex virus-1 (HSV-1) using laser-based scanning of near-infrared fluorophores conjugated antibodies

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    Among several strategies used for Herpes simplex virus (HSV) detection in biological specimens, standard plaque assay (SPA) remains the most reliable method to evaluate virus infectivity and quantify viral replication. However, it is a manual procedure, thereby affected by operator subjectivity, and it may be particularly laborious for multiple sample analysis. Here we describe an innovative method to perform the titration of HSV type 1 (HSV-1) in different samples, using the “In-Cell WesternTM” Assay (ICW) from LI-COR, a quantitative immunofluorescence assay that exploits laser-based scanning of near infrared (NIR). In particular, we employed NIR-immunodetection of viral proteins to monitor foci of HSV-1 infection in cell monolayers, and exploited an automated detection of their fluorescence intensity to evaluate virus titre. This innovative method produced similar and superimposable values compared to SPA, but it is faster and can be performed in 96 well plate, thus allowing to easily and quickly analyze and quantify many samples in parallel. These features make our method particularly suitable for the screening and characterization of antiviral compounds, as we demonstrated by testing acyclovir (ACV), the main anti-HSV-1 drug. Moreover, we developed a new data analysis system that allowed to overcome potential bias due to unspecific florescence signals, thus improving data reproducibility. Overall, our method may represents a useful tool for both clinical and research purposes

    Thermal treatment of bamboo with flame: influence on the mechanical characteristics

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    The mechanical properties of bamboo are susceptible to degradation due to both physical and biological agents. Among the non-chemical treatments, we studied the influence of a short-time heat treatment, using an LPG-gas torch, on the mechanical properties of a bamboo (Phyllostachys viridiglaucescens) growing in Italy. The response was very encouraging as we found no significant reduction in either elastic modulus or tensile, compressive and bending strength. Several samples were subject to tension, compression and bending tests to compare the responses of the treated and untreated culms. The average tensile elastic modulus was slightly greater for the untreated culms. The average tensile strength of the untreated culms was only slightly greater, and the differences can be assumed to be insignificant from a structural point of view. The average value of the treated culms compressive elastic modulus was slightly greater than that of the untreated ones. The compressive strength was essentially the same. The bending mechanical behaviour was barely influenced by the thermal treatment. A microscopic investigation (optical and electron microscopy) was undertaken to investigate the possible deterioration of the bamboo microstructure due to the heat treatment. No appreciable damage was detectable in the treated material. The proposed heat treatments can be considered as a reliable and sustainable protection practice for bamboo culms

    Effect of oxide nanoparticles on thermal and mechanical properties of electrospun separators for lithium-ion batteries

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    This study reports the fabrication and characterization of poly(ethylene oxide) (PEO) and poly(vinylidenefluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) nanofibrous separators for lithium-ion batteries loaded with different amounts of fumed-silica and tin oxide nanoparticles. Membrane morphological characterization (SEM, TEM) showed the presence of good-quality nanofibres containing nanoparticles. Thermal degradation and membrane mechanical properties were also investigated, and a remarkable effect of nanoparticle addition on membrane mechanical properties was found. In particular, PEO membranes were strengthened by the addition of metal oxide, whereas PVDF-CTFE membranes acquired ductility

    Numerical simulations of fuel shape change and swirling flows in paraffin/oxygen hybrid rocket engines

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    The objective of this work is to describe and validate a numerical axisymmetric approach for the simulation of hybrid rocket engines (HREs), based on Reynolds-averaged Navier–Stokes simulations, with sub-models for fluid–surface interaction, radiation, chemistry, and turbulence. Fuel grain consumption is considered on both radial and axial directions and both axial and swirl injection of the oxidizer are simulated. Firing tests of two different paraffin–oxygen hybrid rockets are considered. First, a numerical rebuilding of fuel grain profile, regression rate and pressure for axial-injected HREs is performed, yielding a reasonable agreement with the available experimental data. Then, the same numerical model is applied to swirl-injected HREs and employed to analyze both the flowfield and the regression rate variation with swirl intensity. A validation of the model through the rebuilding of small-scale firing tests is also performed

    Laparoscopic Cholecystectomy in Cirrhotic Patient

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    Cholecystectomy is associated with increased risk in patients with liver cirrhosis. Moreover, cirrhosis and portal hypertension have been considered relative or absolute contraindication to laparoscopic cholecystectomy. As experience with laparoscopic cholecystectomy increased, we decided to treat cirrhotic patients via this approach. Between January 1994 and April 1995, nine patients with a Child-Pugh's stage A cirrhosis underwent elective laparoscopic cholecystectomy with intraoperative cholangiography. There was no significant per- or post-operative bleeding and no blood transfusion was necessary. There was no mortality and very low morbidity. Median hospital stay was 3 days. This series suggests that wellcompensated cirrhosis can not be considered a contraindication to laparoscopic cholecystectomy

    A Study of background for IXPE

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    Focal plane X-ray polarimetry is intended for relatively bright sources with a negligible impact of background. However this might not be always possible for IXPE (Imaging X-ray Polarimetry Explorer) when observing faint extended sources like supernova remnants. We present for the first time the expected background of IXPE by Monte Carlo simulation and its impact on real observations of point and extended X-ray sources. The simulation of background has been performed by Monte Carlo based on GEANT4 framework. The spacecraft and the detector units have been modeled, and the expected background components in IXPE orbital environment have been evaluated. We studied different background rejection techniques based on the analysis of the tracks collected by the Gas Pixel Detectors on board IXPE. The estimated background is about 2.9 times larger than the requirement, yet it is still negligible when observing point like sources. Albeit small, the impact on supernova remnants indicates the need for a background subtraction for the observation of the extended sources.Comment: 16 pages, 16 figure

    Piezoelectric Nanofibers for Integration in Multifunctional Materials

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    This paper deals with realization of multifunctional composite materials, having piezoelectric effect. First of all polymeric mats of electrospun piezoelectric nanofibers were realized with different geometries. Such effect has been maximized by designing properly the electrospinning apparatus in order to enhance the electric field in the interelectrodic space which polarize the dipolar moments. The mats are then integrated in a silicon rubber matrix and measurements of the electromechanical response of the composite materials thus manufactured are performed. A good integration of nanofibers inside the host material is evidenced by electron microscopy images, allowing delaminations, which could occur using piezoelectric films, to be avoided. A large electrical response to both impact and vibration stimuli has been finally demonstrated

    Sustainable New Brick and Thermo-Acoustic Insulation Panel from Mineralization of Stranded Driftwood Residues

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    There is considerable interest recently in by-products for application in green buildings. These materials are widely used as building envelope insulators or blocks. In this study, an experimental study was conducted to test stranded driftwood residues as raw material for possible thermo-acoustic insulation panel and environmentally sustainable brick. The thermal and acoustic characteristics of such a natural by-product were examined. Part of samples were mineralized by means of cement-based additive to reinforce the material and enhance its durability as well as fire resistance. Several mixtures with different sizes of ground wood chips and different quantities of cement were investigated. The thermo-acoustic in-lab characterization was aimed at investigating the thermal conductivity, thermal diffusivity, volumetric specific heat, and acoustic transmission loss. All samples were tested before and after mineralization. Results from this study indicate that it is possible to use stranded driftwood residues as building materials with competitive thermo-acoustic properties. In fact, the thermal conductivity was shown to be always around 0.07 W/mK in the unbound samples, and around double that value for the mineralized samples, which present a much higher volumetric specific heat (1.6 MJ/m3K) and transmission loss capability. The lignin powder showed a sort of intermediate behavior between the unbound and the mineralized samples.The authors would like to thank Gabriele Franceschetti and CVR s.r.l. for assisting the mineralization procedure of the samples. Anna Laura Pisello’s acknowledgments are due to the “CIRIAF program for UNESCO” in the framework of the UNESCO Chair “Water Resources Management and Culture”, for supporting her research. The research was founded by the Italian Environmental Ministry with an agreement entitled “Recovery and energy valorization of stranded driftwood residues” in 2014–2016. The research team leading to these results has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 657466 (INPATH–TES) and No. 678407 (ZERO-PLUS)
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