A New Method for Characterization of Natural Zeolites and Organic Nanostructure using Atomic Force Microscopy

In order to study and develop an economic solution to environmental pollution in water, a wide variety of materials were investigated. Natural zeolites emerge from that research as the best in class of this category. Zeolites are natural materials relatively abundant and non biodegradable, economic and good to perform processes of environmental remediation. This paper contains a full description of a new method to characterize superficial properties of natural zeolites of exotic provenience (Caribbean Islets) with atomic force microscopy (AFM). AFM works with the optical microscope simplicity and the high resolution typical of a transmission electron microscope (TEM). Structural information of mesoporous material is obtained using scanning and transmission electron microscopy (SEM and TEM), only if the sample is conductive, otherwise the sample has to be processed through the grafitation technique, but this procedure induces errors of topography. Therefore, the existing AFM method, to observe zeolite powders, is made in a liquid cell-head scanner, but this work puts in evidence and confirms that it is possible to use an ambient air-head scanner to obtain a new kind of microtopography. Once optimized, this new method allows investigating of organic micelles, very soft nanostructure, of cetyltriammonium bromide (CTAB) upon an inorganic surface such as natural zeolites. It is shown some correlation between SEM microphotographies and AFM 3D images

Insulin-like growth factor-1 is a negative modulator of glucagon secretion

Glucagon secretion involves a combination of paracrine, autocrine, hormonal, and autonomic neural mechanisms. Type 2 diabetes often presents impaired glucagon suppression by insulin and glucose. Insulin-like growth factor-I (IGF-1) has elevated homology with insulin, and regulates pancreatic β-cells insulin secretion. Insulin and IGF-1 receptors share considerable structure homology and function. We hypothesized the existence of a mechanism linking the inhibition of α-cells glucagon secretion to IGF-1. Herein, we evaluated the association between plasma IGF-1 and glucagon levels in 116 nondiabetic adults. After adjusting for age gender and BMI, fasting glucagon levels were positively correlated with 2-h post-load glycaemia, HOMA index and fasting insulin, and were negatively correlated with IGF-1 levels. In a multivariable regression, the variables independently associated to fasting glucagon were circulating IGF-1 levels, HOMA index and BMI, explaining 20.7% variation. To unravel the molecular mechanisms beneath IGF-1 and glucagon association, we investigated whether IGF-1 directly modulates glucagon expression and secretion in an in vitro model of α-cells. Our data showed that IGF-1 inhibits the ability of low glucose concentration to stimulate glucagon expression and secretion via activation of the phosphatidylinositol-3-kinase/Akt/FoxO1 pathway. Collectively, our results suggest a new regulatory role of IGF-1 on α-cells biological function

Determination of carbonyl compounds in exhaled breath by on-sorbent derivatization coupled with thermal desorption and gas chromatography-tandem mass spectrometry

A reliable method for the determination of carbonyl compounds in exhaled breath based on on-sorbent derivatization coupled with thermal desorption and gas chromatography-tandem mass spectrometry is described. The analytical performances were optimized for a mixture of C2-C9 aldehydes and C3-C9 ketones, particularly interesting for clinical applications, by using an internal standard and applying a 2^3 full factorial design. A volume of sample (250 ml) was loaded at 50 ml min-1 into a Tenax GR sorbent tube containing 130 nmol of O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride. All compounds showed a limit of detection lower than 200 pptv. The yield of the derivatization procedure was normalized by adding to the sample a known amount of 6D-acetone as an internal standard. This allowed halving the relative standard deviation to 10% and 15% for the mono-and di-carbonyl compounds, respectively, thus improving reliability. The optimized method was applied to the determination of carbonyl compounds in 12 breath samples collected from four patients suffering from heart failure during hospitalization

A GNR e as Operações de Apoio à Paz: Legitimidade e limites de actuação

O presente trabalho de investigação aplicada está subordinado ao tema: ―A GNR e as Operações de Apoio à Paz: Legitimidade e Limites de Actuação‖. As operações de apoio à paz são uma realidade do mundo actual e a participação da GNR nestas operações tem sido uma constante. Neste sentido, a legitimidade desta participação tem sido ao longo dos anos questionada, tese esta que é debatida neste trabalho. Para além da legitimidade, são também aqui debatidos quais são os limites de actuação desta força militar em operações deste tipo. Neste contexto, desenvolve-se um estudo através da pergunta de partida: "De que forma a participação nas OAP é importante para a GNR? E para o País?." Os principais objectivos do trabalho são responder às perguntas supra mencionadas, verificar a legitimidade da participação da GNR neste tipo de operações, compreender o conceito das regras de empenhamento e a sua criação e, finalmente , identificar a importância destas regras para a decisão de um comandante. O trabalho iniciou-se com uma fase exploratória, procedendo-se em seguida à pesquisa com particular incidência em livros, legislação e textos relacionados com o tema, tendo sido tam bém utilizada a internet como fontes de informação sobre as operações de apoio à paz. A investigação de campo baseou-se na análise de conteúdo das entrevistas efectuadas, o que permitiu responder às perguntas de investigação através da verificação das hipó teses formuladas. Após a análise dos dados, conclui-se que a GNR tem legitimidade para participar nestas operações, o que está contemplado na sua lei orgânica, e que, em simultâneo, estas participações revelam elevada importância não só para a GNR como para o País. No entanto, para que exista uma melhor preparação das forças que executam estas missões será necessário que o novo Centro de Treino e Aprontamento para Forças de Missões Internacionais entre em funcionamento com uma estrutura diferente da planeada. O presente trabalho foi realizado entre Janeiro e Março de 2009.Abstract This investigation project was developed under the theme: ―The GNR (Portuguese Republican National Guard) and the Peace Operations: Legitimacy and Action Limits. The peace-support operations are a reality in our contemporary world and the GNR's participation in these operations has been a constant. Considering this, the legitimacy of such participations has been questioned over the years, fact that led to the thesis discussed along this work. In addition to legitimacy, the limits of military force in such operations are also debated. In this context, this project was based on two former question s: "What is the meaning of the GNR participation in the peace operations? And for the country?". The main goals of the project are answering the questions above, confirming the legitimacy of GNR's participation in such operations, understanding the rules of engagement and its creation and, at last, identifying the rules importance for a commander’s decision. The project began with an exploratory phase, followed by a research work supported by books, legislation and texts on the subject as well as the Internet as sources of information on peace-support operations. The field research was developed by analysing the conducted interviews, which allowed the research to answer the questions while checking the assumptions previously made. After analyzing the data, it is concluded that the GNR is entitled to participate in these operations, which is included in its organic law, and, simultaneously, these actions reveal high importance not only for the GNR but for the country also. Nevertheless, in order to get a better preparation of the forces that will carry out these missions, changes in structure and functioning of the new Training Centre are needed. This work was developed from January to March 2009

The Florence Statement on Triclosan and Triclocarban

The Florence Statement on Triclosan and Triclocarban documents a consensus of more than 200 scientists and medical professionals on the hazards of and lack of demonstrated benefit from common uses of triclosan and triclocarban. These chemicals may be used in thousands of personal care and consumer products as well as in building materials. Based on extensive peer-reviewed research, this statement concludes that triclosan and triclocarban are environmentally persistent endocrine disruptors that bioaccumulate in and are toxic to aquatic and other organisms. Evidence of other hazards to humans and ecosystems from triclosan and triclocarban is presented along with recommendations intended to prevent future harm from triclosan, triclocarban, and antimicrobial substances with similar properties and effects. Because antimicrobials can have unintended adverse health and environmental impacts, they should only be used when they provide an evidence-based health benefit. Greater transparency is needed in product formulations, and before an antimicrobial is incorporated into a product, the long-term health and ecological impacts should be evaluated

Ejection of damaged mitochondria and their removal by macrophages ensure efficient thermogenesis in brown adipose tissue

Recent findings have demonstrated that mitochondria can be transferred between cells to control metabolic homeostasis. Although the mitochondria of brown adipocytes comprise a large component of the cell volume and undergo reorganization to sustain thermogenesis, it remains unclear whether an intercellular mitochondrial transfer occurs in brown adipose tissue (BAT) and regulates adaptive thermogenesis. Herein, we demonstrated that thermogenically stressed brown adipocytes release extracellular vesicles (EVs) that contain oxidatively damaged mitochondrial parts to avoid failure of the thermogenic program. When re-uptaken by parental brown adipocytes, mitochondria-derived EVs reduced peroxisome proliferator-activated receptor-γ signaling and the levels of mitochondrial proteins, including UCP1. Their removal via the phagocytic activity of BAT-resident macrophages is instrumental in preserving BAT physiology. Depletion of macrophages in vivo causes the abnormal accumulation of extracellular mitochondrial vesicles in BAT, impairing the thermogenic response to cold exposure. These findings reveal a homeostatic role of tissue-resident macrophages in the mitochondrial quality control of BAT