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Hydrogels are three-dimensional crosslinked materials known for their ability to absorb water, exhibit high flexibility, their biodegradability and biocompatibility, and their ability to mimic properties of different tissues in the body. However, their application is limited by inherent deficiencies in their mechanical properties. To address this issue, reduced graphene oxide (rGO) and tannins (TA) were incorporated into alginate hydrogels (Alg) to evaluate the impact of the concentration of these nanomaterials on mechanical and adhesive, as well as cytotoxicity and wound-healing properties. Tensile mechanical tests demonstrated improvements in tensile strength, elastic modulus, and toughness upon the incorporation of rGO and TA. Additionally, the inclusion of these materials allowed for a greater energy dissipation during continuous charge-discharge cycles. However, the samples did not exhibit self-recovery under environmental conditions. Adhesion was evaluated on pig skin, revealing that higher concentrations of rGO led to enhanced adhesion, while the concentration of TA did not significantly affect this property. Moreover, adhesion remained consistent after 10 adhesion cycles, and the contact time before the separation between the material and the surface did not affect this property. The materials were not cytotoxic and promoted healing in human fibroblast-model cells. Thus, an Alg/rGO/TA hydrogel with enhanced mechanical, adhesive, and wound-healing properties was successfully developed.
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The two trapped quantum particles interacting problem is generalized to three dimensions, and the exact Coulomb potential is used. The system is solved by expanding the wavefunction in terms of the isotropic harmonic oscillator eigenfunctions and Hydrogen atom eigenfunctions independently, showing that each one results in a prime approximation for different domains of the normalized coupling constant of the relative interactions, suggesting that the combination of the basis is enough to build a well-suited base for the non-approximate problem. The results are compared to previous works that use a model of approximate finite-rage soft-core interaction model of the problem to give insights into the many-body states of strongly correlated ultracold bosons and fermions. We conclude that the proposed three-dimensional approach facilitates the distinction between bosons and fermions while the solutions given by the expansions better define the behavior of the particles for repulsive potentials. In addition, we discuss the substantial differences between our work and the previous approximate model.
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In this study, a conductive composite material, based on graphene oxide (GO), nanocellulose (CNF), and tannins (TA) from pine bark, reduced using polydopamine (PDA), was developed for wound dressing. The amount of CNF and TA was varied in the composite material, and a complete characterization including SEM, FTIR, XRD, XPS, and TGA was performed. Additionally, the conductivity, mechanical properties, cytotoxicity, and in vitro wound healing of the materials were evaluated. A successful physical interaction between CNF, TA, and GO was achieved. Increasing CNF amount in the composite reduced the thermal properties, surface charge, and conductivity, but its strength, cytotoxicity, and wound healing performance were improved. The TA incorporation slightly reduced the cell viability and migration, which may be associated with the doses used and the extract's chemical composition. However, the in-vitro-obtained results demonstrated that these composite materials can be suitable for wound healing.
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Mice are commonly infected with Nippostrongylus brasiliensis (Nb) to study their immune responses. However, biosecurity measures have not been established for housing Nb-infected mice and rats. Transmission reportedly does not occur when infected mice are cohoused with naive mice. To test this, we inoculated female NOD. Cg-Prkdcscid Il2rgtm1Wjl /Sz(NSG;n = 12) and C57BL/6J (B6;n = 12) mice with 750 Nb L3 larvae. These mice were then cohoused with naïve NSG ( n = 24) and B6 ( n = 24) mice (1 infected and 2 naïve mice per cage (24 cages) for 28 d in static microisolation cages that were changed every 14 d. We also did several studies to determine the conditions that favor horizontal transmission. First, we assessed in vitro development to the L3 stage of Nb egg-containing fecal pellets maintained under 4 environmental conditions (dry, moist, soiled bedding, and control). Second, we assessed infection of naïve NSG mice ( n = 9) housed in microisolation cages that contained soiled bedding spiked with infective L3 larvae (10,000/cage). Third, we gavaged NSG mice ( n = 3) with Nb eggs to model the potential for infection after coprophagy. We found that naïve NSG (9 of 24) and B6 (10 of 24) mice cohoused with an infected cagemate passed Nb eggs in feces as early as 1 d after cohousing and intermittently thereafter for varying periods. This shedding was presumably the result of coprophagy because adult worms were not detected in the shedding mice at euthanasia. Although eggs developed in vitro into L3 larvae under moist and control environmental conditions, none of the NSG mice housed in cages with L3 -spiked bedding or gavaged with eggs became infected with Nb. These findings indicate that infectious horizontal transmission does not occur when mice are housed with Nb-shedding cage mates in static microisolation cages with a 14-d cage-changing interval. Results from this study can be used to inform biosecurity practices when working with Nb-infected mice.
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Biosseguridade , Nippostrongylus , Camundongos , Animais , Ratos , Feminino , Camundongos Endogâmicos NOD , Camundongos Endogâmicos C57BL , Abrigo para Animais , Camundongos SCIDRESUMO
We suggest a theoretical framework to study the dynamics of an open city, with cars entering at a certain rate and leaving as they reach their destinations. In particular, we assess through simulations some unexpected consequences of the massive use of GPS (global positioning system) navigation systems in the overall dynamics. One of our main interest is to identify what type of measurements would be the most relevant for an experimental study of this system, specifically, the ones useful for city traffic administrators. To do so, we solve the microdynamics using a cellular automaton model considering three different navigation strategies based on the minimization of the individual paths (unweighted strategy) or travel times (weighted strategies). Although the system is inherently stochastic, we found in our simulations an equivalent saddle-node bifurcation for all strategies where the input rate acts as a bifurcation parameter. There is also evidence of additional bifurcations for travel time minimization based strategies. Although we found that weighted strategies are more efficient in terms of car motion, there is a destabilization phenomenon that makes, in an unexpected way, a variation of the unweighted strategy more optimal at certain densities from the fuel efficiency of the overall city traffic point of view. These results bring new insight into the intrinsic dynamics of cities and the perturbations that individual traffic routing can produce on the city as a whole.
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We develop two novel models of the H2+ molecule and its isotopes from which we assess quantum-mechanically and semi-classically whether the molecule anti-aligns with the field in the first excited electronic state. The results from both models allow us to predict anti-alignment dynamics even for the HD+ isotope, which possesses a permanent dipole moment. The molecule dissociates at angles perpendicular to the field polarization in both the excited and the ground electronic state, as the population is exchanged through a conical intersection. The quantum mechanical dispersion of the initial state is sufficient to cause full dissociation. We conclude that the stabilization of these molecules in the excited state through bond-hardening under a strong field is highly unlikely.
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In this study, the simultaneous degradation of antibiotics (ampicillin, sulfamethazine, and tetracycline; and non-steroidal anti-inflammatories (diclofenac and salicylic acid)) including the total organic carbon abatement by solar photoelectro-Fenton process was assessed. Eight liters of solution containing the mixture of the five pharmaceuticals in 1 mmol L-1 Fe2+, 0.05 mol L-1 Na2SO4 at pH 3 and 35 °C were electrolyzed applying different current densities (j = 10, 25, and 50 mA cm-2) in a solar-electrochemical pilot plant. The pilot plant was equipped with an electrochemical filter press cell with a dimensionally stable anode (DSA type) and an air-diffusion cathode coupled to a solar photoreactor exposed directly to sunlight radiation. All pharmaceuticals were degraded during the first 10 min. A TOC removal efficiency of 99.2% after 100 min of treatment with an energy consumption of 534.23 kW h (kgTOC)-1 and 7.15 kW h m-3 was achieved. The pharmaceutical concentration decay followed a pseudo-first-order kinetics. The specific energy per unit of mass of ampicillin, diclofenac, salicylic acid, sulfamethazine, and tetracycline was obtained at 11.73, 19.56, 35.2, 11.73, and 39.32 kW h (kgPD)-1 for ampicillin, diclofenac, salicylic acid, sulfamethazine, and tetracycline, respectively. With our results, we demonstrated that SPEF is an emerging technology for the treatment of this type of pollutants in short time.
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Poluentes Ambientais , Preparações Farmacêuticas , Poluentes Químicos da Água , Técnicas Eletroquímicas , Eletrodos , Peróxido de Hidrogênio , Ferro , Oxirredução , Luz SolarRESUMO
Here, we address the consequences of the extension in the space of a simple model of a system that is closed to efficient causation: the (M,R)-system model. To do so, we use a diffusion term to describe the collective motion of the nutrients' concentration across the compartmentalized space that defines the organism. We show that the non-trivial stable steady state remains despite such generalization, as long as the system is small enough to deal with the transport of the precursors to feed the entire protocell and dispose of a sufficient concentration of it in its surroundings. Such consideration explains the emergence of a bifurcation with two parameters that we characterize. Finally, we show that the robustness of the system under catastrophic losses of catalysts also remains, preserving the original's model character.
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A fast and robust approach to controlling the quantum state of a multi-level quantum system is investigated using a twofrequency time-varying potential. A comparison with other related approaches in the context of a two-level system is also presented, showing similar times and fidelities. As a concrete example, we study the problem of a particle in a box with a periodically oscillating infinite square-well potential, from which we obtain results that can be applied to systems with periodically oscillating boundary conditions. We show that the transition between the ground and first excited state is about 20 times faster than the one performed using a single frequency, both with fidelity of 99.97%. The transition time is about 3.5 times the minimum allowed by quantum mechanics. A test of the robustness of the approach is presented, concluding that, counter-intuitively, it is not only faster but also easier to tune up two frequencies than one. This robustness makes the approach suitable for real applications.
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Resumen Una plena comprensión de los procesos regulatorios requiere tomar en cuenta su dimensión política, hasta ahora escasamente considerada en la literatura de administración pública. A este objetivo contribuye el concepto de poder empresarial que ha desarrollado la economía política. Como lo demuestra el estudio de caso de Transantiago, resulta de especial interés la vertiente estructural del poder empresarial. El process tracing aplicado al caso de este sistema de transporte demuestra que la incapacidad de las autoridades de imponer sus preferencias se debe principalmente a las restricciones estructurales que enfrentan, cuyos efectos se manifiestan de manera distinta en la etapa de adjudicación de la licitación y en la fase de implementación.
Resumo O pleno entendimento dos processos regulatórios exige considerar sua dimensão política, até agora raramente considerada na literatura da administração pública. O conceito de poder de negócio desenvolvido pela economia política contribui para esse objetivo. Como demonstra o estudo de caso do Transantiago, o poder estrutural dos negócios é de especial interesse. O process tracing aplicado ao caso desse sistema de transporte, inaugurado em 2007, mostra que a incapacidade das autoridades em impor suas preferências se deve principalmente às restrições estruturais que enfrentam, cujos efeitos variam na fase de leilão e implementação do processo de regulação.
Abstract Full understanding of regulatory processes requires taking into account their political dimension, until now rarely considered in public administration literature. The concept of 'business power' developed in comparative political economy contributes to comprehend this dimension. The case study of the transport system "Transantiago" presented in this article demonstrates that businesses' structural power is of special interest. The process tracing applied to the case of Transantiago, shows that the inability of the authorities to impose their preferences is mainly due to the structural constraints they faced. The effects of this inability are observed in the bidding process and in the phase of implementation of the regulation process.