排序方式: 共有88条查询结果,搜索用时 31 毫秒
51.
Dr. Carolina L. de Moura Dr. Juan Gallo Dr. Lorena García-Hevia Prof. Dr. Otília D. L. Pessoa Prof. Dr. Nágila M. P. S. Ricardo Dr. Manuel Bañobre-López 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(20):4531-4538
To fight against cancer, smarter drugs and drug delivery systems are required both to boost the efficiency of current treatments while reducing deleterious side effects, and combine diagnosis/monitoring with therapy (theranosis) in the search for the final goal of personalized medicine. This work presents the design, preparation, and proof-of-principle validation of a novel hybrid organic–inorganic nanocomposite joining together non-invasive imaging capabilities through magnetic resonance imaging and externally actuated therapeutic properties through a combination of chemo- and thermotherapy. The lipidic matrix of the nanocomposite was composed of carnauba wax, which was simultaneously dual loaded with magnetite nanoparticles and the anticancer drug Oncocalyxone A. Obtained formulations were fully characterized and showed outstanding performances as T2-contrast agents in magnetic resonance imaging (r2>800 mm −1 s−1), heat generating sources in magnetic hyperthermia (specific absorption rate, SAR>200 W g−1Fe), and magnetically responsive drug delivery vehicles. The potential of the designed formulations as theranostic agents was validated in vitro and results indicated a synergistic thermo/chemotherapeutic effect derived from heat generation and controlled drug delivery to cancer growth. Thereby, this external control over the drug delivery profile and the integrated imaging capability open the door to personalized cancer medicine and real-time monitoring of tumor progression. 相似文献
52.
A. Pianelli J. Parka P. Perkowski R. Caputo E. Otón M. Mrukiewicz 《Liquid crystals》2019,46(7):1001-1012
In this work, we studied and analysed a particular variety of liquid crystals, the so-called dual-frequency nematic liquid crystals (DFNLCs). The interest was to perform dielectric spectroscopy and optical characterisation with two pure and doped mixtures of DFNLCs. By means the dielectric spectroscopy we observed a low value of crossover frequency at room temperature for one dye doped mixture. Additionally, in the spectra studies, a scattering of light at cross-frequency, and a stable and unstable focal conical state was observed, respectively, for the investigated mixtures. 相似文献
53.
54.
Jéssica Santos Stefano Luiz Otávio Orzari Habdias Araujo Silva-Neto Vanessa Neiva de Ataíde Letícia Francine Mendes Wendell Karlos Tomazelli Coltro Thiago Regis Longo Cesar Paixão Bruno Campos Janegitz 《Current Opinion in Electrochemistry》2022
Electrochemistry combined with economical and sustainable platforms (such as paper) provides portable, affordable, robust, and user-friendly devices. In general, techniques, such as photolithography and sputtering, are excellent alternatives for producing these platforms. However, owing to the requirement of expensive and sophisticated instrumentation, as well as cleanroom facilities, these techniques have limited access. Thus, the search for easy to use and produce approaches have been reported, using consumables, including adhesives, carbon ink, graphite, pencil, office paper, paperboard, among others. In this sense, in this mini-review, we discuss various strategies explored to fabricate low-cost electrochemical sensors, including its main applications. Different manufacturing methods, such as screen and stencil printing, laser-scribing, and pencil drawing, will be discussed here, emphasizing the performance of the obtained devices, in addition to their advantages and disadvantages. 相似文献
55.
Fuica Francisco Otárola Enrique 《Journal of Optimization Theory and Applications》2022,194(2):543-569
Journal of Optimization Theory and Applications - We propose and analyze a posteriori error estimators for an optimal control problem that involves an elliptic partial differential equation as... 相似文献
56.
Enrique Otárola 《Numerical Methods for Partial Differential Equations》2020,36(2):302-328
We propose and analyze an a posteriori error estimator for a partial differential equation (PDE)-constrained optimization problem involving a nondifferentiable cost functional, fractional diffusion, and control-constraints. We realize fractional diffusion as the Dirichlet-to-Neumann map for a nonuniformly PDE and propose an equivalent optimal control problem with a local state equation. For such an equivalent problem, we design an a posteriori error estimator which can be defined as the sum of four contributions: two contributions related to the approximation of the state and adjoint equations and two contributions that account for the discretization of the control variable and its associated subgradient. The contributions related to the discretization of the state and adjoint equations rely on anisotropic error estimators in weighted Sobolev spaces. We prove that the proposed a posteriori error estimator is locally efficient and, under suitable assumptions, reliable. We design an adaptive scheme that yields, for the examples that we perform, optimal experimental rates of convergence. 相似文献
57.
Maria Conceição M. Torres Raimundo Braz‐Filho Edilberto R. Silveira Jaécio Carlos Diniz Francisco Arnaldo Viana Otília Deusdênia L. Pessoa 《Helvetica chimica acta》2010,93(2):375-381
Two new terpenoids, the bisnorditerpene rel‐(5β,8α,10α)‐8‐hydroxy‐13‐methylpodocarpa‐9(11),13‐diene‐3,12‐dione ( 1 ) and the guaiane sesquiterpene rel‐(1R,4S,6R,7S,8aR)‐decahydro‐1‐(hydroxymethyl)‐4,9,9‐trimethyl‐4,7‐(epoxymethano)azulen‐6‐ol ( 2 ), together with seven known compounds, were isolated from Croton regelianus var. matosii. The structures of the isolated compounds were determined by HR‐ESI‐TOF and a combination of 1D‐ and 2D‐NMR experiments. 相似文献
58.
Antônio João da Silva Filho Otávio Luís de Santana Elizete Ventura do Monte Silmar Andrade do Monte 《International journal of quantum chemistry》2020,120(23):e26391
For the first time, multireference configuration interaction with singles and doubles (MR-CISD) calculations (including extensivity corrections, MR-CISD+Q) have been performed to study the ring-opening reactions of the following mesoionic rings and their 2, 3, and 4 methyl-substituted derivatives: ( a ) 1,3-oxazol-5-one, ( c ) 1,3-oxazol-5-thiolate, and ( d ) 1,3-thiazol-5-thiolate. The ring-opening reaction of the parent 1,3-thiazol-5-one mesoionic ring ( b ) has also been studied. The effect of methyl and S replacement on the reaction and activation free energies (ΔG and ΔG†, respectively) is studied. For a , the effect of methyl replacement on C2 is almost negligible, while on N3 and C4, it is significantly larger, especially in the latter position. The open structure (ketene form) of a is considerably more stable, and the replacement of the exocyclic O by S stabilizes the ketene tautomer even more and increases ΔG† considerably. On the other hand, replacement of the endocyclic O by S (yielding b ) completely prevents the formation of the open structure, while replacement of both endo and exo atoms strongly stabilizes the cyclic structure and leads to a remarkably high value of ΔG†. In some cases, the relative polarity of the stationary points is used to estimate how ΔG and ΔG† are expected to change as one goes from the gas phase to aprotic polar solvents. A linear correlation between the multiconfigurational character of the mesoionic rings and ΔG† has been observed, and such correlation is used to estimate the ΔG† values for the methyl-substituted c and d . The largest barrier (13.78 kcal/mol) has been obtained for the 4-methyl-1,3-thiazol-5-thiolate (4-m- d ). 相似文献
59.
Russany Silva da Costa Charles Alberto Brito Negrão Sarah Regina Pereira Camelo Roseane Maria Ribeiro-Costa Wagner Luiz Ramos Barbosa Carlos Emmerson Ferreira da Costa José Otávio Carréra Silva Júnior 《Journal of Thermal Analysis and Calorimetry》2013,111(3):1959-1964
Thermogravimetric (TG) techniques and differential scanning calorimetry (DSC) used for the study of pre-formulation or drug–adjuvant compatibility have been gaining importance in Brazil. These techniques are being used for the verification of possible interactions between drugs and adjuvants. Aiming at studying the behavior of a plant extract and its mixture with adjuvants, using these thermoanalytical techniques the plant species Heliotropium indicum L. was used. This plant which is originally from India and has been well acclimatized in Brazil has healing and anti-inflammatory properties. The methodology for obtaining the extract followed the Brazilian Pharmacopoeia methodology. And the incorporation of the extract with adjuvants was through binary mixtures (1:1 w/w). The TG and DSC curves were obtained under nitrogen atmosphere (25 mL min?1) at a heating rate of 5 °C min?1; TG tests were analyzed within a temperature range from 25 to 600 °C and DSC from 25 to 300 °C. The TG curves show good thermal stability of the extract and its mixtures with adjuvants up to 150 °C, except the propylene glycol (PLG). The DSC curves revealed an incompatibility of the extract with methylparaben and PLG mixture. 相似文献
60.
B. Bellini M. A. Geday N. Bennis A. Spadło X. Quintana J. M. Otón R. Dąbrowski 《Opto-Electronics Review》2006,14(4):269-273
Liquid crystal (LC) phased arrays and gratings have been employed in optical switching and routing [1]. These diffractive
optic elements are of great interest because they can be scaled up to a large number of elements and their optical properties
can be electrically addressed with a low driving voltage. LC phase gratings have been achieved either by periodic addressing
of pixels or by using periodically-modified structures. The latter approach leads to less reconfigurable devices but the addressing
is simpler.
In this paper we focus on optical phased arrays where the phase is varied either continuously or discretely and where the
periodicity is induced by electrode configuration. We first describe a possible structure based on a conductive silicon wafer.
We argue that this structure can induce either continuously or discretely varying arrays while applying single voltage to
the array. In the second part we simulate the behaviour of such arrays. We base the simulation on a LC synthesized at the
Military University of Technology, this high-birefringence nematic LC shows in a 4-μm thick cell a linear phase shift range
of more than 360° between 1.2 V and 1.8 V. We calculate the distribution of the LC molecule director and assess the performance
of the array with respect to the applied voltage. Finally, the relevance of such technology for switchable phased arrays is
discussed. 相似文献