Developing green and nontoxic biomaterials, derived from renewable sources and processable through 3D bioprinting technologies, is an emerging challenge of sustainable tissue engineering. Here, ...pectin from citrus peels was cross-linked for the first time with (3-glycidyloxypropyl)trimethoxysilane (GPTMS) through a one-pot procedure. Freeze-dried porous pectin sponges, with tunable properties in terms of porosity, water uptake, and compressive modulus, were obtained by controlling GPTMS content. Cell experiments showed that GPTMS did not affect the cytocompatibility of pectin. The addition of GPTMS improved the printability of pectin due to an increase of viscosity and yield stress. Three-dimensional woodpile and complex anatomical-shaped scaffolds with interconnected micro- and macropores were, therefore, bioprinted without the use of any additional support material. These results show the great potential of using pectin cross-linked with GPTMS as biomaterial ink to fabricate patient-specific scaffolds, which could be used to promote tissue regeneration in vivo.
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•Oxidized fuel form an oil-oil complex emulsion.•Oxidized fossil diesel presents the most dense and viscous oxidation products, but it is the slowest fuel to demix and to form ...deposits, i.e. products mass weight has a second order impact on deposits formation.•The polarity of the oxidized fuel seems to play a major role in the liquid film deposits formation.
The thermal and oxidation stability of fatty acids methyl esters (FAME) is arousing attention in the transport industry, since they are the main components present in biodiesel products used in the market. Low FAME stability can induce easy fuel degradation and produce oxidation products that can form sticky deposit causing serious malfunctioning and failures of engine and turbines components. We have focused the present work on the study of fuel oxidation process and the characterization of oxidation products in order to identify the main levers to avoid deposit formation. Soy and Rapeseed biodiesels were oxidized using an autoclave Parr reactor and characterized by FTIR, density and viscosity measurements. After oxidation, two different liquid phases were clearly observed. These two phases tend to form complex oil-oil emulsions after remixing as evidenced by optical microscopy. The separation behavior of the different liquid phases remixed after oxidation were studied using Multiple Light Scattering (TurbiscanTM). A comparison was made between the chemical functions of deposit obtained in the liquid phase after demixing (sedimented phase) and the solid deposit obtained on hot metallic surfaces. Results showed a that a complex oil-oil dispersion seems to form during the oxidation process. The phase separation rate of the oil-oil emulsified systems formed from oxidized fuels seems strongly related to the differences of polarity (e.g. oxygenates content) of both sedimented and supernatant phases. The understanding of this sedimentation or “demixing” process leading to deposit can be a key feature to develop strategies to prevent deposit formation in real systems.
Revascularisation is a key step for tissue regeneration and complete organ engineering. We describe the generation of human platelet lysate gel (hPLG), an extracellular matrix preparation from human ...platelets able to support the proliferation of endothelial colony forming cells (ECFCs) in 2D cultures and the formation of a complete microvascular network in vitro in 3D cultures. Existing extracellular matrix preparations require addition of high concentrations of recombinant growth factors and allow only limited formation of capillary-like structures. Additional advantages of our approach over existing extracellular matrices are the absence of any animal product in the composition hPLG and the possibility of obtaining hPLG from patients to generate homologous scaffolds for re-implantation. This discovery has the potential to accelerate the development of regenerative medicine applications based on implantation of microvascular networks expanded ex vivo or the generation of fully vascularised organs.
Light-to-Light: PV-Fed LED Lighting Systems Femia, Nicola; Fortunato, M.; Vitelli, M.
IEEE transactions on power electronics,
08/2013, Letnik:
28, Številka:
8
Journal Article
Recenzirano
This paper discusses the principle of operation, dynamic modeling, and control design for light-to-light (LtL) systems, whose aim is to directly convert the sun irradiation into artificial light. The ...system discussed in this paper is composed by a photovoltaic (PV) panel, an LED array, a dc-dc converter dedicated to the maximum power point tracking of the PV panel and a dc-dc converter dedicated to drive the LEDs array. A system controller is also included, whose goal is to ensure the matching between the maximum available PV power and the LED power by means of a low-frequency LEDs dimming. An experimental design example is discussed to illustrate the functionalities of the LtL system.
A multi-energy calibration method was applied for the determination of chromium and nickel in nickeliferous ores by laser-induced breakdown spectroscopy. For the optimization of the laser-induced ...breakdown spectroscopy parameters, such as laser fluence and delay time, an experimental study was conducted. The best results in terms of trueness were observed using a laser fluence and a delay time of 2500 J/cm2 and 1.1 μs, respectively. A study of sample matrix effects and the determination of emission lines for calibration and normalization of the spectra were undertaken, and appropriate values of those variables were selected for each analyte. The trueness values for chromium and nickel varied from 89 to 114% when certified reference samples (nickeliferous laterite, rock phosphate and contaminated soil) were analyzed.
Deoxyribose-1-phosphate (dRP) is a proangiogenic paracrine stimulus released by cancer cells, platelets, and macrophages and acting on endothelial cells. The objective of this study was to clarify ...how dRP stimulates angiogenic responses in human endothelial cells.
Live cell imaging, electron paramagnetic resonance, pull-down of dRP-interacting proteins, followed by immunoblotting, gene silencing of different NADPH oxidases (NOXs), and their regulatory cosubunits by small interfering RNA (siRNA) transfection, and experiments with inhibitors of the sugar transporter glucose transporter 1 (GLUT1) were utilized to demonstrate that dRP acts intracellularly by directly activating the endothelial NOX2 complex, but not NOX4. Increased reactive oxygen species generation in response to NOX2 activity leads to redox-dependent activation of the transcription factor nuclear factor kappa B (NF-κB), which, in turn, induces vascular endothelial growth factor receptor 2 (VEGFR2) upregulation. Using endothelial tube formation assays, gene silencing by siRNA, and antibody-based receptor inhibition, we demonstrate that the activation of NF-κB and VEGFR2 is necessary for the angiogenic responses elicited by dRP. The upregulation of VEGFR2 and NOX2-dependent stimulation of angiogenesis by dRP were confirmed in excisional wound and Matrigel plug vascularization assays in vivo using NOX2
mice.
For the first time, we demonstrate that dRP acts intracellularly and stimulates superoxide anion generation by direct binding and activation of the NOX2 enzymatic complex.
This study describes a novel molecular mechanism underlying the proangiogenic activity of dRP, which involves the sequential activation of NOX2 and NF-κB and upregulation of VEGFR2. Antioxid. Redox Signal. 28, 110-130.
Deposit formation from the gasoline autoxidation process has attracted more and more attention since the emergence of new systems operating at a higher pressure range and higher temperatures, ...imposing new fuel constraints and so favoring the appearance of deposits on different engine parts in contact with the fuel (e.g., injection systems, valves, pumps, and pistons). This study aims to evaluate the oxidation stability of a non-additized standard European gasoline SP95 Euro 6 containing 10% v/v ethanol (SP95E6E10) complying with the EN228 standard and the impact of additives such as methylcyclopentadienyl manganese tricarbonyle (MMT) and dimethyl disulfide (DMDS) on deposit formation to mimic other world market fuels such as Africa or China. The stability of these fuels was compared to that of a commercial Nigerian gasoline which has a higher sulfur content (800 mg/kg) to evaluate the sulfur effect on deposit formation. The fuel degradation tendencies induction period (IP) obtained from a PetroOxy apparatus and an Autoclave reactor were compared to the real engine tendencies to form deposits. The deposits targeted are those created on the injector nozzle of a VW EA111 engine (direct injection) and on the valve using an M102E engine (indirect injection). PetroOxy results show the negative impact of DMDS and MMT on the IP of the gasoline, SP95 E10 ULG Euro 6: an IP decrease of up to 30%. Comparison of the IP results in PetroOxy and Autoclave with the results of the direct injection (VW EA111) and indirect injection (M102E) engine tests suggests that the PetroOxy results follow the trend of the mass of deposits formed on the valves of the indirect injection, M102E, engine tests, with the IP decreasing as the valve deposit mass increases. On the contrary, the Autoclave results appear to follow the trend of the results of the direct injection, VW EA111 engine tests: IP decreases when the injection time increases. These features could allow us to identify fuel tendencies to form deposits on specific spare parts based only on laboratory-scale methods, helping to optimize and to target the maintenance operation and preventing failures or damages on real engine systems.
Magnetic refrigeration offers an energy efficient and environmental friendly alternative to conventional vapor‐cooling. However, its adoption depends on materials with tailored magnetic and ...structural properties. Here a high‐throughput computational workflow for the design of magnetocaloric materials is introduced. Density functional theory calculations are used to screen potential candidates in the family of MM'X (M/M’ = metal, X = main group element) compounds. Out of 274 stable compositions, 46 magnetic compounds are found to stabilize in both an austenite and martensite phase. Following the concept of Curie temperature window, nine compounds are identified as potential candidates with structural transitions, by evaluating and comparing the structural phase transition and magnetic ordering temperatures. Additionally, the use of doping to tailor magnetostructural coupling for both known and newly predicted MM'X compounds is predicted and isostructural substitution as a general approach to engineer magnetocaloric materials is suggested.
Magnetic cooling requires optimized compounds, such as when magnetic and structural transitions to occur concurrently. A computational workflow for the discovery of magnetocaloric materials is proposed and implemented for a family of intermetallic compounds. Out of 274 stable compounds, nine exhibit are predicted to show structural transitions. Chemical disorder strategies are proposed for further improvement.
We demonstrate the protection of one bit of quantum information against all collective noise in three nuclear spins. Because no subspace of states offers this protection, the quantum bit was encoded ...in a proper noiseless subsystem. We therefore realize a general and efficient method for protecting quantum information. Robustness was verified for a full set of noise operators that do not distinguish the spins. Verification relied on the most complete exploration of engineered decoherence to date. The achieved fidelities show improved information storage for a large, noncommutative set of errors.
In the present work, the anti-inflammatory and antiasthmatic potential of biseugenol, isolated as the main component from
-hexane extract from leaves of
and chemically prepared using oxidative ...coupling from eugenol, was evaluated in an experimental model of mixed-granulocytic asthma. Initially, in silico studies of biseugenol showed good predictions for drug-likeness, with adherence to Lipinski's rules of five (RO5), good Absorption, Distribution, Metabolism and Excretion (ADME) properties and no alerts for Pan-Assay Interference Compounds (PAINS), indicating adequate adherence to perform in vivo assays. Biseugenol (20 mg·kg
) was thus administered intraperitoneally (four days of treatment) and resulted in a significant reduction in both eosinophils and neutrophils of bronchoalveolar lavage fluid in ovalbumin-sensitized mice with no statistical difference from dexamethasone (5 mg·kg
). As for lung function parameters, biseugenol (20 mg·kg
) significantly reduced airway and tissue damping in comparison to ovalbumin group, with similar efficacy to positive control dexamethasone. Airway hyperresponsiveness to intravenous methacholine was reduced with biseugenol but was inferior to dexamethasone in higher doses. In conclusion, biseugenol displayed antiasthmatic effects, as observed through the reduction of inflammation and airway hyperresponsiveness, with similar effects to dexamethasone, on mixed-granulocytic ovalbumin-sensitized mice.
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