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The development of biosafe theranostic nanoplatforms has attracted great attention due to their multifunctional behavior, reduced potential toxicity, and improved long-term safety. When considering photoacoustic contrast agents and photothermal conversion tools, melanin and constructs like melanin are highly appealing due to their ability to absorb optical energy and convert it into heat. Following a sustainable approach, in this study, silver-melanin like-silica nanoplatforms are synthesized exploiting different bio-available and inexpensive phenolic acids as potential melanogenic precursors and exploring their role in tuning the final systems architecture. The UV-Vis combined with X-Ray Diffraction investigation proves metallic silver formation, while Transmission Electron Microscopy analysis reveals that different morphologies can be obtained by properly selecting the phenolic precursors. By looking at the characterization results, a tentative formation mechanism is proposed to explain how phenolic precursors' redox behavior may affect the nanoplatforms' structure. The antibacterial activity experiments showed that all synthesized systems have a strong inhibitory effect on Escherichia coli, even at low concentrations. Furthermore, very sensitive Photoacoustic Imaging capabilities and significant photothermal behavior under laser irradiation are exhibited. Finally, a marked influence of phenol nature on the final system architecture is revealed resulting in a significant effect on both biological and photoacoustic features of the obtained systems. These melanin-based hybrid systems exhibit excellent potential as triggerable nanoplatforms for various biomedical applications.
Assuntos
Escherichia coli , Melaninas , Técnicas Fotoacústicas , Prata , Técnicas Fotoacústicas/métodos , Melaninas/química , Escherichia coli/efeitos dos fármacos , Prata/química , Antibacterianos/farmacologia , Antibacterianos/química , Dióxido de Silício/química , HumanosRESUMO
Hydrogen is expected to largely contribute to the near-future circular economy. Today, most hydrogen is still produced from fossil fuels or renewable pathways with low efficiency and high cost. Herein, a proof of concept for a novel hydrogen production process is proposed, here named cyan hydrogen, inspired by a combination of the green and blue processes, due to the key role played by water and the low carbon content in the gas phase, respectively. The developed novel process, recently patented and demonstrated at the lab scale, is based on successive steps in which ethanol (5.0 mL) and water (10.0 mL) are alternately fed, with a fixed initial amount of sodium metaborate (2.0 g), in a batch reactor at 300 °C. Preliminary results showed the simultaneous production of a 95% v/v hydrogen stream, a polymeric byproduct with a repetitive carbon pattern -CH2-CH2-, and a liquid phase rich in oxygenated chemicals at temperatures lower than conventional hydrogen production processes.
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CeO2 slow redox kinetics as well as low oxygen exchange ability limit its application as a catalyst in solar thermochemical two-step cycles. In this study, Ce0.75Zr0.25O2 catalysts doped with potassium or transition metals (Cu, Mn, Fe), as well as co-doped materials were synthesized. Samples were investigated by X-ray diffraction (XRD), N2 sorption (BET), as well as by electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) to gain insight into surface and bulk features, which were connected to redox properties assessed both in a thermogravimetric (TG) balance and in a fixed bed reactor. Obtained results revealed that doping as well as co-doping with non-reducible K cations promoted the increase of both surface and bulk oxygen vacancies. Accordingly, K-doped and Fe-K co-doped materials show the best redox performances evidencing the highest reduction degree, the largest H2 amounts and the fastest kinetics, thus emerging as very interesting materials for solar thermochemical splitting cycles.
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Humic acids (HA) are considered a promising and inexpensive source for novel multifunctional materials for a huge range of applications. However, aggregation and degradation phenomena in aqueous environment prevent from their full exploitation. A valid strategy to address these issues relies on combining HA moieties at the molecular scale with an inorganic nanostructured component, leading to more stable hybrid nanomaterials with tunable functionalities. Indeed, chemical composition of HA can determine their interactions with the inorganic constituent in the hybrid nanoparticles and consequently affect their overall physico-chemical properties, including their stability and functional properties in aqueous environment. As a fundamental contribution to HA materials-based technology, this study aims at unveiling this aspect. To this purpose, SiO2 nanoparticles have been chosen as a model platform and three different HAs extracted from composted biomasses, manure (HA_Man), artichoke residues (HA_Art) and coffee grounds (HA_Cof), were employed to synthetize hybrid HA-SiO2 nanoparticles through in-situ sol-gel synthesis. Prepared samples were submitted to aging in water to assess their stability. Furthermore, antioxidant properties and physico-chemical properties of both as prepared and aged samples in aqueous environment were assessed through Scanning Electron Microscopy (SEM), N2 physisorption, Simultaneous Thermogravimetric (TGA) and Differential Scanning Calorimetric (DSC) Analysis, Fourier Transform Infrared (FT-IR), Nuclear Magnetic Resonance (NMR), Electron Paramagnetic Resonance (EPR) spectroscopies. The experimental results highlighted that hybrid HA-SiO2 nanostructures acted as dynamic systems which exhibit structural supramolecular reorganization during aging in aqueous environment with marked effects on physico-chemical and functional properties, including improved antioxidant activity. Obtained results enlighten a unique aspect of interactions between HA and inorganic nanoparticles that could be useful to predict their behavior in aqueous environment. Furthermore, the proposed approach traces a technological route for the exploitation of organic biowaste in the design of hybrid nanomaterials, providing a significant contribution to the development of waste to wealth strategies based on humic substances.
Assuntos
Substâncias Húmicas , Nanoestruturas , Idoso , Humanos , Substâncias Húmicas/análise , Masculino , Dióxido de Silício , Espectroscopia de Infravermelho com Transformada de Fourier , ÁguaRESUMO
Green syngas production is a sustainable energy-development goal. Thermochemical H2O/CO2 splitting is a very promising sustainable technology allowing the production of H2 and CO with only oxygen as the by-product. CeO2-ZrO2 systems are well known thermochemical splitting catalysts, since they combine stability at high temperature with rapid kinetics and redox cyclability. However, redox performances of these materials must be improved to allow their use in large scale plants. K-doped systems show good redox properties and repeatable performances. In this work, we studied the effect of potassium content on the performances of ceria-zirconia for CO2 splitting. A kinetic model was developed to get insight into the nature of the catalytic sites. Fitting results confirmed the hypothesis about the existence of two types of redox sites in the investigated catalytic systems and their role at different K contents. Moreover, the model was used to predict the influence of key parameters, such as the process conditions.
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The enzymatic hydrolysis of lignocellulosic biomass-derived compounds represents a valid strategy to reduce the dependence on fossil fuels, with geopolitical and environmental benefits. In particular, ß-glucosidase (BG) enzyme is the bottleneck in the degradation of cellulose because it catalyzes the hydrolysis of cellobiose, a known inhibitor of the other cellulolytic enzymes. However, free enzymes are unstable, expensive and difficult to recover. For this reason, the immobilization of BG on a suitable support is crucial to improve its catalytic performance. In this paper, computational fluid dynamics (CFD) simulations were performed to test the hydrolysis reaction in a monolith channel coated by BG adsorbed on a wrinkled silica nanoparticles (WSNs) washcoat. We initially defined the physical properties of the mixture, the parameters related to kinetics and mass transfers and the initial and boundary conditions thanks to our preliminary experimental tests. Numerical simulation results have shown great similarity with the experimental ones, demonstrating the validity of this model. Following this, it was possible to explore in real time the behavior of the system, varying other specified parameters (i.e., the mixture inlet velocity or the enzymatic load on the reactor surface) without carrying out other experimental analyses.
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BACKGROUND: On 22 December 2017, Law number 219 was approved in Italy entitled "Provisions for informed consent and advance treatment directives". We aim to examine the knowledge of these provisions of Italian medico legal fellows, and the ability of Italian university healthcare facilities to implement the principles of the new law. METHODS: A survey was conducted by means of a questionnaire sent to members of a scientific society. The society had 357 members and represents more than 75% of the Italian doctors in training and 32 university healthcare facilities in Italy. 27 facilities and 45% of the society's members participated in this enquiry. RESULTS: The majority (68%) of those interviewed felt they had acquired an adequate knowledge of the Law but only 60% of them were able to indicate how for filing legally valid advance directives (60% vs. 40%) and only 37% knew how drafting a shared care plan. 89% of the pool felt that legal recognition of a patient's self-determination was useful for enhancing the care relationship. The 74% of the facilities analyzed have organized training activities regarding the contents of the law but only 26% have updated their procedures on the practical implementation of the law and their informed consent forms. 60% of the facilities perform medico legal consultation activities and in 15% of the facilities, there has been resistance to the application of the law. CONCLUSION: Many of the facilities have performed training activities but lack effective implementation of the activities required. With increased knowledge and organization this could be overcome.
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Diretivas Antecipadas/legislação & jurisprudência , Consentimento Livre e Esclarecido/legislação & jurisprudência , Competência Profissional , Humanos , Itália , Conhecimento , Autonomia Pessoal , Médicos , Inquéritos e QuestionáriosAssuntos
Bacteriemia/microbiologia , Biópsia/efeitos adversos , Infecções por Clostridium/complicações , Sepse/microbiologia , Carcinoma Neuroendócrino/patologia , Clostridium perfringens , Evolução Fatal , Humanos , Fígado/patologia , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Obesidade Mórbida , Radiografia Intervencionista , Tomografia Computadorizada por Raios XRESUMO
The current observation of deaths by electrocution, both for domestic and work-related accidents as well as those in other contexts, has deepened the scope of investigation into electric marks, especially from the histological point of view. This is one of the few investigation tools that may lead to the diagnosis of death by electrocution in this distinct area, bearing in mind the diagnostic difficulties that this type of fatality presents. Our attention has been placed on the phenomenon of metallization. In particular, we focused on using the Timm's method [1] to locate the copper deposits. The phenomenon of metallization, usually could be caused by the copper deposit, this happens due to the copper debris released onto the skin by the live conductor. To date, this technique has only been used in the pathological field. Nevertheless, we tried to assess its application in seven selected cases, after partially modifying the technique, comparing it with the most common staining detection techniques and analysing the specificity, sensitivity as well as the potential for its application in the routine.