Search results for "Microscopy"
showing 10 items of 3390 documents
Thermo-Mechanical Behaviour of Flax-Fibre Reinforced Epoxy Laminates for Industrial Applications
2015
The present work describes the experimental mechanical characterisation of a natural flax fibre reinforced epoxy polymer composite. A commercial plain woven quasi-unidirectional flax fabric with spun-twisted yarns is employed in particular, as well as unidirectional composite panels manufactured with three techniques: hand-lay-up, vacuum bagging and resin infusion. The stiffness and strength behaviours are investigated under both monotonic and low-cycle fatigue loadings. The analysed material has, in particular, shown a typical bilinear behaviour under pure traction, with a knee yield point occurring at a rather low stress value, after which the material tensile stiffness is significantly r…
Understanding the White-Emitting CaMoO4 Co-Doped Eu3+, Tb3+, and Tm3+ Phosphor through Experiment and Computation
2019
In this article, the synthesis by means of the spray pyrolysis method, of the CaMoO4 and rare-earth cation (RE3+)-doped CaMoO4:xRE3+ (RE3+ = Eu3+, Tb3+, and Tm3+; and x = 1, 2, and 4% mol) compounds, is presented. The as-synthesized samples were characterized using X-ray diffraction, Rietveld refinement, field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and photoluminescence (PL) spectroscopy. To complement and rationalize the experimental results, first-principles calculations, at the density functional theory level, have been performed to analyze the band structure and density of states. In addition, a theoretical method based on the calculations of surface energie…
Pressure-Dependent Tuning of Photoluminescence and Size Distribution of Carbon Nanodots for Theranostic Anticancer Applications
2020
Carbon nanodots (CDs) have recently attracted attention in the field of nanomedicine because of the biocompatibility, cost-effective nature, high specific surface, good near infrared (NIR) photothermal conversion into heat and tunable fluorescence properties, which have paved the way toward incorporating use of CDs into innovative anticancer theranostic platforms. However, a reliable synthesis of CDs with established and controlled physiochemical proprieties is precluded owing to the lack of full manipulation of thermodynamic parameters during the synthesis, thus limiting their use in real world medical applications. Herein, we developed a robust solvothermal protocol which allow fine contr…
Effect of thermal annealing on the luminescence of defective ZnO nanoparticles synthesized by pulsed laser ablation in water
2016
This work concerns ZnO nanoparticles (NPs), with sizes of tens of nm, produced by ablation with a pulsed Nd:YAG laser of a Zn plate in H2O. TEM images evidence the formation of nanoparticles with sizes of tens of nm. Moreover, HRTEM images and Raman spectra show that the distance between the crystalline planes and the vibrational modes are consistent with ZnO nanocrystal in wurtzite structure. Their optical properties are characterized by two emission bands both excited above the energy gap (3.4 eV): the first at 3.3 eV is associated with excitons recombination, the second at 2.2 eV is proposed to originate from a singly ionized oxygen vacancy. The green emission is independent of water pH,…
Confocal laser scanning microscopy for the study of the morphological changes of the postextraction sites
2012
A better understanding of the remodeling process of postextraction sockets is essential in dental treatment planning. The aim of this study was to evaluate whether confocal laser scanning microscopy (CLSM) can be applied to imaging contour changes of postextraction sites, as well as to its quantification with image analysis of obtained three-dimensional images. This work describes a new application of the CLSM technique. The system used was the OLS3100-USS, LEXT model (Olympus((R))). CLSM was used for the surface analysis of the extraction site. The measurements taken with CLSM were: (1) mesio-distal distance, (2) alveolar ridge thickness, and (3) vestibular and lingual alveolar ridge heigh…
Electronic Energy Meter Based on a Tunnel Magnetoresistive Effect (TMR) Current Sensor
2017
In the present work, the design and microfabrication of a tunneling magnetoresistance (TMR) electrical current sensor is presented. After its physical and electrical characterization, a wattmeter is developed to determine the active power delivered to a load from the AC 50/60 Hz mains line. Experimental results are shown up to 1000 W of power load. A relative uncertainty of less than 1.5% with resistive load and less than 1% with capacitive load was obtained. The described application is an example of how TMR sensing technology can play a relevant role in the management and control of electrical energy.
Prompt Determination of the Mechanical Properties of Industrial Polypropylene Sandwich Pipes
2021
A simple and prompt method to determine the mechanical properties of industrial multilayer extrusion polypropylene pipes for a gravity sewer network is suggested. The engineering formulas included for calculating the permissible thickness and relative position of a foam core in the pipes are based on a linear-elastic approximation and the rule of mixtures. The applicability of the approximation was justified experimentally during investigation of the effective tensile characteristics of single- and multilayer pipes and each layer specimen by using traditional tests and finite-element calculations. The results obtained were used to formulate engineering recommendations for calculations of th…
Observation of the Early Structural Changes Leading to the Formation of Protein Superstructures.
2014
Formation of superstructures in protein aggregation processes has been indicated as a general pathway for several proteins, possibly playing a role in human pathologies. There is a severe lack of knowledge on the origin of such species in terms of both mechanisms of formation and structural features. We use equine lysozyme as a model protein, and by combining spectroscopic techniques and microscopy with X-ray fiber diffraction and ab initio modeling of Small Angle X-ray Scattering data, we isolate the partially unfolded state from which one of these superstructures (i.e., particulate) originates. We reveal the low-resolution structure of the unfolded state and its mechanism of formation, hi…
Peptide-mediated interference with baculovirus transduction
2007
Baculovirus represents a multifunctional platform with potential for biomedical applications including disease therapies. The importance of F3, a tumor-homing peptide, in baculovirus transduction was previously recognized by the ability of F3 to augment viral binding and gene delivery to human cancer cells following display on the viral envelope. Here, F3 was utilized as a molecular tool to expand understanding of the poorly characterized baculovirus-mammalian cell interactions. Baculovirus-mediated transduction of HepG2 hepatocarcinoma cells was strongly inhibited by coincubating the virus with synthetic F3 or following incorporation of F3 into viral nucleocapsid by genetic engineering, th…
Occlusion-derived baculovirus: interaction with human cells and evaluation of the envelope protein P74 as a surface display platform.
2008
To develop complementary baculovirus-based tools for gene delivery and display technologies, the interaction of occlusion-derived baculovirus (ODV) with human cells, and the functionality of the P74 ODV envelope protein for display of the IgG-binding Z domains (ZZP74) were evaluated. The cellular binding of ODV was concentration-dependent and saturable. Only minority of the bound virions were internalized at both 37 and 4 degrees C, suggesting usage of direct membrane fusion as the entry mode. The intracellular transport of ODV was confined in vesicular structures peripheral to the plasma membrane, impeding subsequent nuclear entry and transgene expression. Transduction of ODV was not rescu…