103 research outputs found
Evaluation of Nanoparticle Uptake iii Co-culture Cancer Modeis
Co-culture models are currently bridging the gap between classical cultures and in vivo animal models. Exploring this novel approach unlocks the possibility to mimic the tumor microenvironment in vitro, through the establishment of cancer-stroma synergistic interactions. Notably, these organotypic models offer a perfect platform for the development and pre-clinical evaluation of candidate nanocarriers loaded with anti-tumoral drugs in a high throughput screening mode, with lower costs and absence of ethical issues. However, this evaluation was until now limited to co-culture systems established with precise cell ratios, not addressing the natural cell heterogeneity commonly found in different tumors. Therefore, herein the multifunctional nanocarriers efficiency was characterized in various fibroblast-MCF-7 co-culture systems containing different cell ratios, in order to unravel key design parameters that influence nanocarrier performance and the therapeutic outcome. The successful establishment of the co-culture models was confirmed by the tissue-like distribution of the different cells in culture. Nanoparticles incubation in the various co-culture systems reveals that these nanocarriers possess targeting specificity for cancer cells, indicating their suitability for being used in this illness therapy. Additionally, by using different co-culture ratios, different nanoparticle uptake profiles were obtained. These findings are of crucial importance for the future design and optimization of new drug delivery systems, since their real targeting capacity must be addressed in heterogenous cell populations, such as those found in tumors.PEst-OE/EGEJUI4D5G/201
Quantum field theory approach to the optical conductivity of strained and deformed graphene
The computation of the optical conductivity of strained and deformed graphene is discussed within the framework of quantum field theory in curved spaces. The analytical solutions of the Dirac equation in an arbitrary static background geometry for one dimensional periodic deformations are computed, together with the corresponding Dirac propagator. Analytical expressions are given for the optical conductivity of strained and deformed graphene associated with both intra and interbrand transitions. The special case of small deformations is discussed and the result compared to the prediction of the tight-binding model.The authors acknowledge financial supportfrom the Brazilian agencies FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) and CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico)
MELHORIA NA EFICIÊNCIA DA CLARIFICAÇÃO DE SUCO DE MARACUJÁ PELA COMBINAÇÃO DOS PROCESSOS DE MICROFILTRAÇÃO E ENZIMÁTICO
Este trabalho teve como objetivo a obtenção de suco
clarificado de maracujá, utilizando a técnica de
microfiltração. Introduziu-se a etapa de tratamento
enzimático antes da microfiltração, visando aumentar
a eficiência do processo pela redução da viscosidade
e do teor de polpa do suco. Foram testadas três
diferentes enzimas hidrolíticas em três níveis de
concentração. Os resultados não mostraram
diferenças significativas quanto ao Brix, pH e acidez
das amostras de suco hidrolisado em relação ao suco
integral. Observou-se efeito positivo da ação das
enzimas na redução da viscosidade e do teor de polpa.
A microfiltração foi realizada em sistema de membrana
tubular com tamanho médio de poro equivalente a
0,3 µm e pressão transmembrana de 1,5 bar. O suco
permeado apresentou-se límpido, isento de polpa e com
qualidade e sanidade microbiológica. Tais resultados
comprovaram a eficiência da microfiltração para
clarificação e estabilização de sucos de frutas.
IMPROVEMENT IN THE EFFICIENCY OF PASSION FRUIT JUICE
CLARIFICATION BY THE COMBINATION OF MICROFILTRATION AND
ENZYMATIC PROCESSES
Abstract
This work had as objective the obtention of clarified passion fruit juice by using the
microfiltration technique. A step of enzymatic treatment was introduced before
microfiltration, aiming to enhance process efficiency by reduction of viscosity and
pulp content of the juice. Three different hidrolytic enzymes were tested in three
concentration levels. The results didnt demonstrate significant differences in Brix,
pH and acidity of the hidrolyzed juice samples in relation to the concentrated juice.
Positive effect was observed in the action of the enzymes in the reduction of
viscosity and pulp content. The microfiltration was realized in a tubular membrane
system with average size of the pore equivalent to 0.3 m and transmembrane
pressure of 1.5 bar. The permeate juice was clear, free from pulp and with good
micribiological quality. Such results proved the efficiency of microfiltration for
clarification and stabilization of fruit juices
Impact of regulated and emerging pollutants and microplastics in marine ecosystems (IMPACTA project)
Marine ecosystems are nowadays subjected to a massive input of synthetic chemicals from everywhere. Unfortunately only a small portion of them is being monitored, and it is necessary to identify which pollutants can produce adverse impacts in the marine environment. IMPACTA project (CTM2013-48194-C3) is characterizing the distribution of regulated and emerging contaminants and microplastics in marine sediments, and evaluating the biological effects that they can cause (sing sublethal embryotoxicity tests, endocrine disruption and biomarkers). Sensitive and selective analytical methods are being developed and validated for pharmaceuticals, perfluorinated compounds, organophosphorus pesticides, triazines, personal care products, nonylphenols and alkylated PAHs in sediments. Thus, relevant pollutants present in coastal and offshore areas will be identified. Furthermore potential toxic effects of the contaminants present in coastal sediments are being assessed through embryotoxicity bioassays and also the biological effects on different marine species as a consequence of their exposition to specific compounds.
Another relevant contribution of this project will be the assessment of the impact of micro-plastics, first time in the Spanish coastal areas. Their potential toxic effects and their role in the transference of pollutants in the marine environment are being assessed. The concentration and composition of microplastics in sediments and demersal fish stomachs are being characterized, and their potential biological effects on marine invertebrates are also being investigated
Capsaicin cyclodextrin complex enhances mepivacaine targeting and improves local anesthesia in inflamed tissues
Acidic environments, such as in inflamed tissues, favor the charged form of local anesthetics LA . Hence, these drugs show less cell permeation and diminished potency. Since the analgesic capsaicin CAP triggers opening of the TRPV1 receptor pore, its combination with LAs could result in better uptake and improved anesthesia. We tested the above hypothesis and report here for the first time the analgesia effect of a two drug combination LA and CAP on an inflamed tissue. First, CAP solubility increased up to 20 times with hydroxypropyl beta cyclodextrin HP amp; 946; CD , as shown by the phase solubility study. The resulting complex HP amp; 946; CD CAP showed 1 1 stoichiometry and high association constant, according to phase solubility diagrams and isothermal titration calorimetry data. The inclusion complex formation was also confirmed and characterized by differential scanning calorimetry DSC , X ray diffraction, and 1H NMR. The freeze dried complex showed physicochemical stability for at least 12 months. To test in vivo performance, we used a pain model based on mouse paw edema. Results showed that 2 mepivacaine injection failed to anesthetize mice inflamed paw, but its combination with complexed CAP resulted in pain control up to 45 min. These promising results encourages deeper research of CAP as an adjuvant for anesthesia in inflamed tissues and cyclodextrin as a solubilizing agent for targeting molecules in drug deliver
Internal heating and thermal emission from old neutron stars: Constraints on dense-matter and gravitational physics
The equilibrium composition of neutron star matter is achieved through weak
interactions (direct and inverse beta decays), which proceed on relatively long
time scales. If the density of a matter element is perturbed, it will relax to
the new chemical equilibrium through non-equilibrium reactions, which produce
entropy that is partly released through neutrino emission, while a similar
fraction heats the matter and is eventually radiated as thermal photons. We
examined two possible mechanisms causing such density perturbations: 1) the
reduction in centrifugal force caused by spin-down (particularly in millisecond
pulsars), leading to "rotochemical heating", and 2) a hypothetical
time-variation of the gravitational constant, as predicted by some theories of
gravity and current cosmological models, leading to "gravitochemical heating".
If only slow weak interactions are allowed in the neutron star (modified Urca
reactions, with or without Cooper pairing), rotochemical heating can account
for the observed ultraviolet emission from the closest millisecond pulsar, PSR
J0437-4715, which also provides a constraint on |dG/dt| of the same order as
the best available in the literature.Comment: 6 pages, 7 figures. To appear in the proceedings of "Isolated Neutron
Stars: from the Interior to the Surface", a conference held in London in
April 2006 (special issue of Astrophysics and Space Science, edited by Dany
Page, Roberto Turolla, & Silvia Zane
Energetic status of crossbreed dairy cows during transition period in two different seasons
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