Exploiting the fluorescence resonance energy transfer (FRET) between CdTe quantum dots and Au nanoparticles for the determination of bioactive thiols.

This work focused the implementation of FRET processes between CdTe quantum dots (QDs), acting as donors, and gold nanoparticles (AuNPs), behaving as acceptors, for the determination of several bioactive thiols such as captopril, glutathione, l-cysteine, thiomalic acid and coenzyme M. The surface chemistry of the QDs and AuNPs was adjusted with adequate capping ligands, i.e. mercaptopropionic acid and cysteamine, respectively, to guarantee the establishment of strong electrostatic interaction between them and promoting the formation of stable FRET assemblies. Under these circumstances the fluorescence emission of the QDs was completely suppressed by the AuNPs. The assayed target analytes were capable of disrupting the donor-acceptor assemblies yielding a concentration-related reversion of the FRET process and restoring QDs fluorescence emission. Distinct mechanisms, involving enhancing of the QDs quantum yield (QY), AuNPs agglomeration, nanoparticles detachment, etc., could be proposed to explain the referred FRET reversion. The developed approach assured good analytical working ranges and demonstrate adequate sensitivity for the assayed compounds, anticipating great prospective for implementing rapid, simple and reliable sensing methodologies for the monitoring of pharmaceutical, food and environmental species. However, selectivity could be a hindrance in the detection of these bioactive thiols in more complex matrices such as environmental and food samples. This problem could be circumvented through the employment of multivariate chemometric methods for the analysis and processing of whole fluorometric response. Moreover, the proposed methodology shows a great analytical versatility since it is possible to easily adapt the surface chemistry, of both QDs and AuNPs, to the chemical nature of the target analyte.

Produtos de pescado elaborados com resíduos de arrasto: análise físico-química, microbiológica e toxicológica / Fish products made from trawl fishery waste: physical, chemical, microbiologic, and toxicological analysis

Na pesca de arrasto, são inúmeras as espécies de peixe capturadas acidentalmente, compostas, em sua maioria, de espécimes de pequeno tamanho e baixo valor comercial, os quais recebem o nome de rejeito de pesca. O presente trabalho teve como objetivo o desenvolvimento de dois produtos, almôndega e quibe de peixe, tendo como matéria- prima espécies consideradas capturas acidentais na modalidade de pesca de arrasto realizada no litoral do Rio de Janeiro. A identificação taxonômica das espécies teve como resultado as espécies pargo (Pagrus pagrus), castanha (Umbrina sp.), olho-de-cão (Priacanthus arenatus), congro-negro (Conger sp.), congro-rosa (Genypterus brasiliensis) e peixe-sapo (Lophius gastrophysus). A matéria seca percentual na polpa foi de 31,20±1,30%, no quibe e na almôndega crus; os valores foram de 37,90±1,10 e 32,10±1,10, respectivamente. Nos produtos assados, os resultados foram 33,40±1,20 para o quibe e 34,20±1,00 para a almôndega. Os teores de cinzas na polpa foram 1,5% para o quibe e a almôndega crus; os valores de cinzas foram de 2,55±0,05 e 1,47±0,05, respectivamente. Para os produtos assados, os resultados foram 1,87±0,05 para o quibe e 1,92±0,05 para a almôndega. Os teores de lipídeos aferidos na polpa foram de 4,80±0,30%. Com relação ao quibe e à almôndega crus, o percentual de lipídeos foi de 4,20±0,80 e 4,20±0,60, respectivamente. Para os produtos assados, foi de 4,50±0,60 para o quibe e 4,40±0,60 para a almôndega. A proteína bruta apresentou, na polpa, um índice de 15,60±1,04%. Com relação ao quibe e à almôndega crus, 17,80±2,16 e 14,90±2,12, respectivamente. Para os produtos assados, 15,10±2,10 em ambos. Os compostos nitrogenados solúveis, formadores do NNP, apresentaram valores de 285mg NNP/100g de polpa de pescado crua, 291mg NNP/100g no quibe cru e 294mg NNP/100g na almôndega crua. Os resultados da contagem total de psicrotróficos mantiveram-se abaixo de log 7,0UFC/g, para contagem padrão em placas de microrganismos aeróbicos. Não foi constatada a presença de coliformes fecais Salmonella e Staphylococcus aureus. Também não foram detectados níveis de histamina e compostos à base de enxofre nas amostras.(AU)

Seafood products represent an important source of proteins and minerals as well as polyunsaturated fatty acids. However, its consumption in Brazil is very low in comparison to other kinds of meat. This may due to lack of skill in its preparation, making immensurable the importance of the search for new ways to market it, such as ready-made or semi-ready to serve products. The trawl fishery method often accidentally captures a variety of species, composed basically of low commercial value and size. Such catches are called "second-hand catch". With this in mind, this paper has as its main objective de development of two products: fish meatball and kibe, using what is considered accidental catches in the trawl fishery industry done on Rio de Janeiro's offshore as the raw material. The taxonomic identification of the species resulted in the species, Red porgy (Pagrus pagrus), Argentine croaker (Umbrina sp.), Atlantic bigeye (Priacanthus arenatus), Black cusk-eel (Conger sp.), Cusk-eel (Genypterus brasiliensis) and Blackfin goosefish (Lophius gastrophysus). The dry material of the raw product was 31.20±1.30%, in the raw meatball and kibbeh the values was 37.90±1.10 and 32.10±1.10, respectively, in the baked product the results was 33.40±1.20 and 34.20±1.00 (kibbeh and meatball). The ash content in the pulp was 1.5%, for the raw kibbeh and meatball, the amounts of ash were 2.55±0.05 and 1.47±0.05, respectively. For baked goods results were 1.87±0.05 for the kibbeh and 1.92±0.05 for the meatball. The measured lipid levels in the pulp was 4.80±0.30%. In respect, raw kibbeh and meatball, the percentage of lipids were 4.20±0.80 and 4.20±0.60, respectively. For baked goods was 4.50±0.60 for the kibbeh and 4.40±0.60 for the meatball. The protein level presented in the raw material was 15.60±1.04%, to the raw kibbeh and meatball was 17.80±2.16 and 14.90±2.12 and for the baked goods 15.10±2.10 both. Soluble nitrogen compounds shows values of 285mg/100g in the raw material, in the kibbeh NNP 291mg/100g and the meatball NNP 294mg/100g. The results of the total count of psychotropic remained below 7.0 log CFU/g, for standard count of aerobic microorganism plates. Fecal coliform bacteria, Salmonella, and Staphylococcus aureus were not present . The levels of histamine and sulfur basic compounds (H2S) were not detected in the samples.(AU)

Cartogenina associada à microperfuração do osso subcondral na reparação da cartilagem articular em equinos / Kartogenin associated to micro of the subchondral bone in the joint cartilage repair in horses

A reconstituição da cartilagem articular danificada por doenças de desenvolvimento, trauma e osteoartrite tem sido um grande desafio na veterinária. O objetivo do presente estudo foi avaliar o uso da cartogenina, uma molécula capaz de induzir diferenciação de células mesenquimais em condrócitos, associado ou não à técnica de microfratura na reparação de defeitos condrais induzidos na tróclea femoral de equinos. Foram utilizados seis equinos pesando em média (±DP) 342±1,58kg, com idade de 7,2±1,30 anos e escore corporal de 7,1±0,75, os quais foram submetidos à videoartroscopia para indução da lesão condral de 1cm2 na tróclea lateral do fêmur e à realização da técnica de microperfuração do osso subcondral de ambos os joelhos. Foram realizadas quatro aplicações semanais com 20µM de cartogenina intra-articular em um dos joelhos (grupo tratado) e solução de ringer com lactato na articulação contralateral (grupo controle). Os animais foram submetidos a avaliações física, radiográfica, ultrassonográfica, por um período de 60 dias. Não houve qualquer diferença estatística entre as articulações tratadas e as controle. A terapia com cartogenina, segundo protocolo utilizado, não produziu melhora clínica em lesões osteocondrais induzidas e tratadas com microperfurações na tróclea lateral do fêmur em equinos.(AU)

Articular cartilage reconstruction is still a challenge in Veterinary Medicine. The aim was to evaluate the therapeutic effects of kartogenin, a small molecule that promotes chondrocyte differentiation, in the repair of induced chondral defects pretreated with subchondral drilling. Six horses with a mean (± SD) weight of 342 ± 1.58Kg, aging 7.2 ± 1.30 years, and with a mean 7.1 ± 0.75 body score condition were used. In both stifles, a 1cm2 chondral defect was induced in the lateral femoral trochlea followed by treatment with subchondral drilling. Four intra-articular injections with kartogenin (20mM) were performed weekly in one stifle (treated group). The same procedure using saline solution was performed in the contralateral joint (control group). Clinical, radiographic, ultrasound evaluations were performed for a period of 60 days. No statistical differences were detected between groups in any of the studied variables. Although kartogenin has shown to improve articular cartilage repair in laboratory animal models, the same was not observed in this equine model. In conclusion, the kartogenin therapy, according to the used protocol, did not promote any clinical benefit in equine femoral trochlear defects pretreated with subcondral drilling.(AU)

Chemiluminometric determination of ascorbic acid in pharmaceutical formulations exploiting photo-activation of GSH-capped CdTe quantum dots.

An automated multi-pumping flow system is proposed for the chemiluminometric determination of ascorbic acid in pharmaceutical formulations, relying on the ability of semiconductor nanocrystals to generate short-lived reactive species upon photo-irradiation. A photo-unit based on visible-light-emitting diodes is used to photo-excite cadmium telluride (CdTe) quantum dots capped with glutathione, leading to the generation of radicals that react with luminol under alkaline conditions, yielding the chemiluminescence. Ascorbic acid acts as a radical scavenger, preventing the oxidation of luminol, thus ensuring a concentration-dependent chemiluminescence quenching. After system optimization, a linear working range of 5.0 × 10(-7) to 5.0 × 10(-6) mol/L ascorbic acid (r = 0.9967, n = 5) was attained, with a detection limit of 3.05 × 10(-7) mol/L and a sampling rate of 200/h. The flow system was applied to the analysis of pharmaceutical formulations and the results were in good agreement with those obtained by the reference titrimetric procedure (RD < ± 4.3%, n = 7).

Self-association and stereochemistry study of 2-methylthio-, 2-dimethylaminocyclohexanone oximes and the parent cyclohexanone oxime.

X-ray diffraction analyses of 2-substituted cyclohexanone oximes C5H9(X)C=NOH [X = SMe (1), NMe2 (2)] and of the parent compound [X = H (3)] showed that their cyclohexyl rings are in a slightly distorted chair conformation. These compounds assume in the solid state the (E) configuration bearing the 2-substituents in the axial conformation. Compounds (1) and (2) exist as dimeric and polymeric hydrogen-bond associates, respectively. Low-temperature X-ray analysis of the cyclohexanone oxime (3) showed that the molecules are associated forming two independent trimers. The dimer in (1) and the trimer in (3) are built up via [O-H...N=C] hydrogen bonds, while the polymer of (2) is via the [OH...NMe2] hydrogen bond. The comparative IR nu(OH) and nu(C=N) analysis of the title compounds, in the solid state and in CCl4 solution, fully supports the nature of the associates for (1)-(3) obtained by X-ray diffraction. The IR azomethyne frequency shift analysis (Deltanu(C=N)) also suggests the occurrence of the pi(C=N)/sigma*(C-X) orbital interaction which stabilizes the axial conformations of (1) and (2).