Studies on the biodistribution of dextrin nanoparticles

The characterization of biodistribution is a central requirement in the development of biomedical applications based on the use of nanoparticles, in particular for controlled drug delivery. The blood circulation time, organ biodistribution and rate of excretion must be well characterized in the process of product development. In this work, the biodistribution of recently developed self-assembled dextrin nanoparticles is addressed. Functionalization of the dextrin nanoparticles with a DOTA-monoamide-type metal chelator, via click chemistry, is described. The metal chelator-functionalized nanoparticles were labeled with the ᵧ-emitting 153Sm3+ radioisotope and the blood clearance rate and organ biodistribution of the nanoparticles were obtained. The effect of PEG surface coating on the blood clearance rate and organ biodistribution of the nanoparticles was also studied.The authors wish to acknowledge funding through the FCT/POCTI programme (project PTDC/QUI/70063/2006)

Cell adhesion and proliferation of skeletal muscle cells on piezoelectric poly(vinylidene fluoride) membranes

Several body tissues, including bone and muscle, are subjected to electromechanical solicitations during their functional activity [1-3]. Thus, the use of electroactive polymers as active scaffolds shows innovative large potential for tissue engineering applications as it offers functional resemblance to biological clues [2]. In particular, piezoelectric polymers have shown suitability for tissue engineering due to their ability to vary surface charge when a mechanical load is applied [4] and their possibility to be processed in form of films, porous 2D and 3D membranes and scaffolds and fiber mats. The influence of poling state and morphology (film or fiber morphology) of piezoelectric poly(vinylidene fluoride) (PVDF) on the adhesion and morphology of myoblast cells was studied. Non-poled, ‘‘poled +’’ and “poled-’’ !-PVDF films were prepared by solvent casting followed by corona poling. Further, random and aligned electrospun !-PVDF fiber mats were also prepared. It is demonstrated that negatively charged surfaces improve cell adhesion and proliferation and that the directional growth of the myoblast cells can be achieved by culturing the cell on aligned fibers. Therefore, the potential application of electroative materials for muscle regeneration is demonstrated

Propriedades químicas de um latossolo amarelo cultivado com pastagens na Amazônia Oriental.

A pesquisa foi conduzida com o objetivo de avaliar as modificações das propriedades químicas de um Latossolo Amarelo com cultivo de pastagens, submetidos a dois modelos de sistemas rotacionados, nos períodos chuvoso e seco, um com Brachiaria brizantha e o outro com Panicum maximum, nos anos de 1996 e 1997. O delineamento experimental utilizado foi em blocos casualizados, com os tratamentos dispostos num esquema de parcelas subdivididas, com doze repetições. As parcelas foram constituídas pelas forrageiras braquiarão e tobiatã e as subparcelas foram constituídas pelos períodos chuvoso e seco dentro de cada ano. Para o estudo das propriedades químicas do solo, foram coletadas amostras nos períodos chuvoso e seco. O material orgânico incorporado ao solo através de restos de vegetais e a presença de excremento animal alterou as propriedades químicas nos anos estudados. Os teores de Ca, Mg, K, P, MO e o valor de pH foram maiores no ano de 1997. Teores mais elevados de Ca e Mg foram obtidos no sistema de pastejo com tobiatã do que no sistema com braquiarão. No período chuvoso os teores de Mg, K, MO e o valor de pH foram maiores, com exceção de P e Ca para o ano de 1997

Ruminal fermentation and degradation, kinetic flow of the digesta and milk fatty acid composition of cows fed chopped elephantgrass supplemented with soybean oil.

Abstract The aim of this study was to evaluate the ruminal parameters of fermentation and degradation, kinetic flow of rumen digesta, and milk fatty acid composition of cows fed 52% chopped elephantgrass-based diets containing 0.0% (control), 1.5%, 3.0% and 4.5% soybean oil (SO) on a dry matter (DM) basis. Four rumen-cannulated Holstein x Gyr dairy cows with an average milk production of 15.6 ± 3.0 kg day-1 and 90 ± 25 days in milk were allocated in a 4 x 4 Latin square design. The results were analyzed by mixed models. Significant differences were declared at P&#8804;0.05, and P-values from 0.05 < P &#8804; 0.10 were considered as a trend. The inclusion of SO in the diet had no effect on the ruminal pH or total volatile fatty acid concentration, but there was a quadratic effect on the ruminal ammonia nitrogen content and a trend for a linear reduction (P=0.07) in the molar proportion of rumen acetate. Linear reductions were also observed in the DM and neutral detergent fiber (NDF) effective degradabilities of elephantgrass forage, but the fluid and particulate passage rates in the rumen and the DM and NDF intakes were unchanged by SO inclusion in the diet. Milk production, protein and lactose contents and yields were unaltered by dietary SO levels. There were linear reductions in the milk fat and total solids contents, but there was no effect of dietary treatments on their yields. The inclusion of soybean oil in the diet of Holstein x Gyr cows fed chopped elephantgrass improved the nutritional quality of milk fat as a result of increased contents of oleic, rumenic and vaccenic acids, which are beneficial to human health, and a concomitant reduction in hypercholesterolemic saturated fatty acids such as lauric, myristic and palmitic acids

Caracterização dos agroecossistemas e manejo de germoplasma de Citrullus em três regiões do Nordeste brasileiro.

Sendo assim, este trabalho teve como objetivos caracterizar, estudar e descrever os agroecossistemas nordestinos representados pelos distritos de Jamarí-MA, Massaroca-BA e Urimamã-PE

Avaliação de cultivares de pimentão para o cultivo protegido na região de Manaus - AM.

O pimentão é a principal hortaliça produzida em cultivo protegido no estado do Amazonas. Um dos principais problemas neste sistema de cultivo, é a presença de murcha bacteriana, causada por Ralstonia solanacearum, podendo ocasionar perdas acentuadas já no primeiro ciclo de cultivo. Visando avaliar diversos materiais de pimentão e verificar a incidência desta doença, foram avaliadas dez cultivares de pimentão (Nathalie, Maximus, Casca Dura Ikeda, Magali F1, Magali, Margarita, Itapoã, Yollo Wonder, Tico e Rubi Gigante) em condições de cultivo protegido, com fertirrigação, em Manaus - AM

Cochonilhas ocorrentes em cafezais de Rondônia.

A cochonilha é uma praga que provoca grandes prejuízos à cafeicultura no Estado de Rondônia. Este trabalho reúne informações sobre as principais espécies encontradas em Rondônia, assim como os prejuízos causados, o controle biológico e o controle químico para combater esta praga.bitstream/item/24748/1/ct110-cochonilhas.pd