RESUMO
Unsaturated soy phosphatidyl choline (PC) liposomes were systematically analyzed for chemical and physical stability and for influence on membrane fluidity, when quercetin and fish oil were encapsulated. The physical stability of liposomes was lowered with loading, which is mainly due to fish oil leakage. While fish oil did not induce oxidative acceleration, quercetin did not reduce lipid-derived radical formation but it did inhibit hexanal formation. It also showed no relevant effects on membrane fluidity, polarity or partitioning of the spin probe TEMPOL-benzoate (TB), as proved by EPR measurements and simulation. However, increasing concentration of fish oil in a membrane might increase the acyl chain dynamics and therefore apply a more attractive environment for TB. In contrast to the encapsulates increasing fluidity of saturated membranes by disturbing the lipid packing, membrane properties of unsaturated systems with a Tm below 0 °C were not influenced by encapsulation of quercetin or fish oil.
Assuntos
Óleos de Peixe/química , Lipossomos/química , Quercetina/química , Benzoatos/química , Óxidos N-Cíclicos/química , Composição de Medicamentos , Fluidez de Membrana , Oxirredução , Tamanho da Partícula , Solubilidade , Marcadores de SpinRESUMO
In the past, laser-induced breakdown spectroscopy (LIBS) signals have been reported to have a stability independent of the pulse length in solids. In this Letter, we perform the first stability study of femtosecond LIBS in gases (to our best knowledge) and show a significant improvement in signal stability over those achieved with longer pulses. Our study shows that ultrashort-pulse LIBS has an intrinsically higher stability in gas compared to nanosecond-pulse LIBS because of a deterministic ionization process at work in the femtosecond pulse. Relative standard deviations below 1% are demonstrated and are likely only limited by our laser output fluctuations. This enhanced emission stability may open up possibilities for a range of applications, from monitoring rapid gas dynamics to high-quality broadband light sources.
RESUMO
With the continuous development, in the last decades, of analytical techniques providing complex information at single cell level, the study of cell heterogeneity has been the focus of several research projects within analytical biotechnology. Nonetheless, the complex interplay between environmental changes and cellular responses is yet not fully understood, and the integration of this new knowledge into the strategies for design, operation and control of bioprocesses is far from being an established reality. Indeed, the impact of cell heterogeneity on productivity of large scale cultivations is acknowledged but seldom accounted for. In order to include population heterogeneity mechanisms in the development of novel bioprocess control strategies, a reliable mathematical description of such phenomena has to be developed. With this review, we search to summarize the potential of currently available methods for monitoring cell population heterogeneity as well as model frameworks suitable for describing dynamic heterogeneous cell populations. We will furthermore underline the highly important coordination between experimental and modeling efforts necessary to attain a reliable quantitative description of cell heterogeneity, which is a necessity if such models are to contribute to the development of improved control of bioprocesses.
Assuntos
Biologia Celular , Fenômenos Fisiológicos Celulares , Técnicas Citológicas , Modelos Biológicos , Biologia de SistemasRESUMO
Very low-calorie formula diets (VLCDs) are an accepted method of achieving safe and effective weight loss for the morbidly obese. Under supervised medical surveillance and with a support team of dietitians and patient counsellors, weight loss of 40 or more pounds is achieved in 80 percent of patients. The authors present guidelines for assessing responsible weight loss programs along with a list of programs available in New Jersey.
Assuntos
Obesidade Mórbida/dietoterapia , Redução de Peso , Terapia Comportamental , Proteínas Alimentares/administração & dosagem , Feminino , Alimentos Formulados , Humanos , Masculino , New JerseyRESUMO
"This paper deals with questions about the effects of immigrants on three types of capital: the private capital immigrants work with, the public (government) capital that immigrant workers use, and the public capital used for services by immigrants." The geographic focus is on the United States. The authors conclude that although the average cost to natives in 1975 dollars to provide services for immigrants is 4,172 dollars, this amount "is considerably smaller than the benefits of immigrants to natives through their relatively low use of welfare services and their relatively high contribution of taxes." Comments by Jacob Mincer (pp. 95-7) are included.