Dressing liposomal particles with chitosan and poly(vinylic alcohol) for oral vaccine delivery

Liposomes have been used as adjuvants since 1974. One major limitation for the use of liposomes in oral vaccines is the lipid structure instability caused by enzyme activities. Our aim was to combine liposomes that could encapsulate antigens (i.e., Dtxd, diphtheria toxoid) with chitosan, which protects the particles and promotes mucoadhesibility. We employed physical techniques to understand the process by which liposomes (SPC: Cho, 3: 1) can be sandwiched with chitosan (Chi) and stabilized by PVA (poly-vinylic alcohol), which are biodegradable, biocompatible polymers. Round, smooth-surfaced particles of REVs-Chi (reversed-phase vesicles sandwiched by Chi) stabilized by PVA were obtained. The REVs encapsulation efficiencies (Dtxd was used as the antigen) were directly dependent on the Chi and PVA present in the formulation. Chi adsorption on the REVs surface was accompanied by an increase of zeta-potential. In contrast, PVA adsorption on the REVs-Chi surface was accompanied by a decrease of zeta-potential. The presence of Dtxd increased the Chi surface-adsorption efficiency. The PVA affinity by mucine was 2,000 times higher than that observed with Chi alone and did not depend on the molecule being in solution or adsorbed on the liposomal surface. The liberation of encapsulated Dtxd was retarded by encapsulation within REVs-Chi-PVA. These results lead us to conclude that these new, stabilized particles were able to be adsorbed by intestinal surfaces, resisted degradation, and controlled antigen release. Therefore, REVs-Chi-PVA particles can be used as an oral delivery adjuvant.

A ditryptophan cross-link is responsible for the covalent dimerization of human superoxide dismutase 1 during its bicarbonate-dependent peroxidase activity

Unlike intermolecular disulfide bonds, other protein cross-links arising from oxidative modifications cannot be reversed and are presumably more toxic to cells because they may accumulate and induce protein aggregation. However, most of these irreversible protein cross-links remain poorly characterized. For instance, the antioxidant enzyme human superoxide dismutase 1 (hSod1) has been reported to undergo non-disulfide covalent dimerization and further oligomerization during its bicarbonate-dependent peroxidase activity. The dimerization was shown to be dependent on the oxidation of the single, solvent-exposed TrP(32) residue of hSod1, but the covalent dimer was not isolated nor was its structure determined. In this work, the hSod1 covalent dimer was isolated, digested with trypsin in H(2)O and H(2)(18)O, and analyzed by UV-Vis spectroscopy and mass spectrometry (MS). The results demonstrate that the covalent dimer consists of two hSod1 subunits cross-linked by a ditryptophan, which contains a bond between C3 and N1 of the respective Trp(32) residues. We further demonstrate that the cross-link cleaves under usual MS/MS conditions leading to apparently unmodified Trp(32), partially hinders proteolysis, and provides a mechanism to explain the formation of hSod1 covalent trimers and tetramers. This characterization of the covalent hSod1 dimer identifies a novel oxidative modification of protein Trp residues and provides clues for studying its occurrence in vivo. (C) 2010 Elsevier Inc. All rights reserved.

Mitochondrial ATP-sensitive K(+) channels as redox signals to liver mitochondria in response to hypertriglyceridemia

We have recently demonstrated that hypertriglyceridemic (HTG) mice present both elevated body metabolic rates and mild mitochondrial uncoupling in the liver owing to stimulated activity of the ATP-sensitive potassium channel (mitoK(ATP)). Because lipid excess normally leads to cell redox imbalance, we examined the hepatic oxidative status in this model. Cell redox imbalance was evidenced by increased total levels of carbonylated proteins, malondialdehydes, and GSSG/GSH ratios in HTG livers compared to wild type. In addition, the activities of the extramitochondrial enzymes NADPH oxidase and xanthine oxidase were elevated in HTG livers. In contrast, Mn-superoxide dismutase activity and content, a mitochondrial matrix marker, were significantly decreased in HTG livers. isolated HTG liver mitochondria presented lower rates of H(2)O(2) production, which were reversed by mitoK(ATP) antagonists. In vivo antioxidant treatment with N-acetylcysteine decreased both mitoKATP activity and metabolic rates in HTG mice. These data indicate that high levels of triglycerides increase reactive oxygen generation by extramitochondrial enzymes that promote MitoK(ATP) activation. The mild uncoupling mediated by mitoK(ATP) increases metabolic rates and protects mitochondria against oxidative damage. Therefore, a biological role for mitoK(ATP) is a redox sensor is shown here for the first time in an in vivo model of systemic and cellular lipid excess, (C) 2009 Elsevier Inc. All rights reserved.

PVP superabsorbent nanogels

Monomer free hydrogel nanoparticles (nanogels) were prepared by crosslinking preformed poly(N-vinyl-2-pyrrolidone) (PVP) entrapped in the aqueous pool of hexadecyltrimethylammonium bromide reverse micelles using the Fenton reaction. The PVP nanoparticles were spherical with a dry diameter of 27 nm. The diameter of the swollen particles was ten times higher, i.e., a swelling ratio, Q, above 900, characterizing this preparation as superabsorbent. PVP nanogel swelling was dependent on bound Fe(3+) and varied with pH and ionic strength. Nanogel deswelling by salt followed the anions lyotropic series, i.e., SCN(-) < HSO(3)(-) < NO(3)(-) < I(-) < Cl(-) < CH(3)COO(-) < CF(3)SO(3)(-). The value of Q reached 6,000 in iron-free PVP nanoparticles at low pH, making this nanogel one of the most efficient swelling systems so far described.

Evaluation of monolithic columns for determination of formaldehyde and acetaldehyde in sugar cane spirits by High-Performance Liquid Chromatography

High-Performance Liquid Chromatography (HPLC) conditions are described for separation of 2,4-dinitrophenylhydrazone (2,4-DNPH) derivatives of carbonyl compounds in a 10 cm long C-18 reversed phase monolithic column. Using a linear gradient from 40 to 77% acetonitrile (acetonitrile-water system), the separation was achieved in about 10 min-a time significantly shorter than that obtained with a packed particles column. The method was applied for determination of formaldehyde and acetaldehyde in Brazilian sugar cane spirits. The linear dynamic range was between 30 and 600 mu g L-1, and the detection limits were 8 and 4 mu g L-1 for formaldehyde and acetaldehyde, respectively.

Microwave-assisted digestion procedures for biological samples with diluted nitric acid: Identification of reaction products

Microwave-assisted sample preparation using diluted nitric acid solutions is an alternative procedure for digesting organic samples. The efficiency of this procedure depends on the chemical properties of the samples and in this work it was evaluated by the determination of crude protein amount. fat and original carbon. Soybeans grains, bovine blood. bovine muscle and bovine viscera were digested in a cavity-microwave oven using oxidant mixtures in different acid concentrations. The digestion efficiency was evaluated based on the determination of residual carbon content and element recoveries using inductively coupled plasma optical emission spectrometry (ICP OES). In order to determine the main residual organic compounds, the digests were characterized by nuclear magnetic resonance (1 H NMR). Subsequently, studies concerning separation of nitrobenzoic acid isomers were performed by ion pair reversed phase liquid chromatography using a C18 stationary phase, water:acetonitrile:methanol (75:20:5, v/v/v) +0.05% (v/v) TFA as mobile phase and ultraviolet detection at 254 nm. Sample preparation based on diluted acids proved to be feasible and a recommendable alternative for organic sample digestion, reducing both the reagent volumes and the variability of the residues as a result of the process of decomposition. It was shown that biological matt-ices containing amino acids, proteins and lipids in their composition produced nitrobenzoic acid isomers and other organic compounds after cleavage of chemical bonds. (C) 2009 Elsevier B.V. All rights reserved.

Breaking the Conventions : Shakespeare, the Fair Young Man and the Dark Lady

The aim of this essay is to show how Shakespeare’s sonnets violated and reversed the conventional ideas in terms of beauty and idealisation. Furthermore, I will examine the way Shakespeare presented his beloved woman as an absolute opposite of the one created by Petrarch, and how he shifted all the divine metaphors from a woman to a fair young man, creating a new object of praise and admiration.

Elevers uppfattningar av vad man bör uppnå efter avslutad kurs i Idrott och Hälsa A : En studie av två gymnasieskolor i årskurs 2 – ett elevperspektiv

The purpose of this work is to see if the students, on two separate high schools, understand what skills you should achieve after completing the course in physical education and health A 100 points. The entire study is based on a student perspective. In order to best answer the purpose, the questionnaire used in the "available groups" in schools. The questions for the work are: To what extent and how students perceive what they should achieve after completing the course in Sport and Health A?, Which is the goal, based on the curriculum in Physical Education, that students feel are important to achieve? and how do a comparison like between these two schools on the basis of what students perceive that they must achieve in Sport and Health A?The result shows that the main goal that finds support in the course objectives is an assertion; Has knowledge of what to eat to maintain or improve health, which over 90% of students had checked in. The least important goal was the claim 14; Know woods and fields and carry out outdoor activities, as 30% of students had checked in. The most important goal that does not find support in the course objectives is claim 10; to be reversed to the lessons, which was 88% in response rate among students. Here was the least important goal, claim 6; to be skilled in various ball games, which received 17% of student responses. The findings revealed that there is a clear health perspective in physical education in the studied groups at the two schools, one can also see that there is an uneven distribution of the elements included in the curriculum of Sport and Health A, and the outdoor life and dance is rare in the teaching of the groups studied at the two schools. Finally, it appeared that the lesson content and teaching are likely to have a significant role in student perceptions of course goals.

Who Is the Shrew? : Irony as deconstruction in The Taming of the Shrew

In this thesis William Shakespeare’s comedy The Taming of The Shrew is analyzed from a feminist perspective. It is argued that the female characters Katherina and Bianca are mainly constructed through language expressed by male characters as binary oppositions. By an act of deconstruction within the play, these images, or constructed representations, are adjusted and somewhat reversed in the end. In addition, it is shown how the Induction, an introductory part of the play, adds aspects of construction and deconstruction, which supports an ironic reading and a questioning of the constructed gender roles.

Career concerns: a human capital perspective

We introduce human capital accumulation, in the form of learning by doing, in a life cycle model of career concerns and analyze how human capital acquisition a ects implicit incentives for performance. We show that standard results from the career concerns literature can be reversed in the presence of human capital accumulation. Namely, implicit incentives need not decrease over time and may decrease with the degree of uncertainty about an individual's talent. Furthermore, increasing the pre-cision of output measurement can weaken rather than strengthen implicit incentives. Overall, our results contribute to shed new light on the ability of markets to discipline moral hazard in the absence of explicit contracts linking pay to performance.

Ensaios sobre o poder judiciário no Brasil

A tese apresenta três ensaios empíricos sobre os padrões decisórios de magistrados no Brasil, elaborados à partir de bases de dados inéditas e de larga escala, que contém detalhes de dezenas de milhares de processos judiciais na primeira e na segunda instância. As bases de dados são coletadas pelo próprio autor através de programas-robô de coleta em massa de informações, aplicados aos "links" de acompanhamento processual de tribunais estaduais no Brasil (Paraná, Minas Gerais e Santa Catarina). O primeiro artigo avalia - com base em modelo estatístico - a importância de fatores extra-legais sobre os resultados de ações judiciais, na Justiça Estadual do Paraná. Isto é, se os juízes favorecem sistematicamente a parte hipossuficiente (beneficiária de Assistência Judiciária Gratuita). No segundo artigo, estuda-se a relação entre a duração de ações cíveis no primeiro grau e a probabilidade de reforma da sentença, utilizando-se dados da Justiça Estadual de Minas Gerais. O objetivo é avaliar se existe um dilema entre a duração e a qualidade das sentenças. Dito de outra forma, se existe um dilema entre a observância do direito ao devido processo legal e a celeridade processual. O último artigo teste a hipótese - no âmbito de apelações criminais e incidentes recursais no Tribunal de Justiça de Santa Catarina - de que as origens profissionais dos desembargadores influenciam seus padrões decisórios. Isto é, testa-se a hipótese de que desembargadores/relatores oriundos da carreira da advocacia são mais "garantistas" ( e desembargadores oriundos da carreira do Ministério Público são menos "garantistas") relativamente aos seus pares oriundos da carreira da magistratura. Testam-se as hipóteses com base em um modelo estatístico que explica a probabilidade de uma decisão recursal favorável ao réu, em função da origem de carreira do relator do recurso, além de um conjunto de características do processo e do órgão julgador.

Technology adoption and effects of transfers across locations

This paper develops a two-period model with heterogeneous agents to analyze the e¤ects of transfers across locations on convergence, growth and welfare. The model has two important features. First, locations are asymmetric as it is assumed that there are more specialized occupations in the more developed one. Second, the returns on the investment to acquire new technology depend positively on the level of each region’s knowledge and on the level of the world knowledge assumed to be available to all. In one hand, the poor region has a disadvantage as it has a lower stock of knowledge. On the other hand, it has the advantage of not having yet exploited a greater stock of useable knowledge available in the world. Hence, there are two possible cases. When the returns are greater in the poor region, we obtain the following results: (i) the rich location grows slower; (ii) the transfers to the poor location enhances the country’s growth rate; and (iii) there is a positive amount of transfers to the poor region that is welfare improving. When the returns are greater in the rich region, the …rst two results are reversed and transfers to the rich region are welfare improving. In both cases, the optimal amount of transfer increases with the level of income disparity across regions and is not dependent on the level of the country’s economic development (measured by its income per capita). Barriers to the adoption of new technology available in the world can constrain the convergence process as it harms in greater length the poor region. The results do not change whether migration is allowed or not.

The BRICS: some historical experiences, growth challenges and opportunities

The acronym BRICS was a fad among the media and global investors. Now, the acronym sounds passé. However, the group of countries remains important, from both political and economic reasons. They have a large aggregate size, 28% of the global GDP and 42% of the world’s population, high growth potential due to the current significant misallocation of resources and relatively low stock of human capital, structural transformation is in progress and one of them, China, is taking steps to become a global power and a challenger to the US dominance. This paper provides a brief overview of the five economies, Brazil, Russia, India, China and South Africa. We focus on some aspects of their history, the Chinese initiatives in international finance and geopolitical strategic moves, their growth experience and structural transformation over the last 35 years, trade and investment integration into the global economy and among themselves, the growth challenges faced by their economies and the potential gains to the Brazilian economy from a stronger integration with the other BRICS. In association with its efforts to be a global power, China aims to become a major player in global finance and to achieve the status of global currency for the renminbi, which would be the first currency of an emerging economy to attain such position. Despite the similarities, the BRICS encompass very diverse economies. In the recent decades, China and India showed stellar growth rates. On the other hand, Brazil, Russia and South Africa have expanded just in line with global output growth with the Russian economy exhibiting high volatility. China is by far the largest economy, and South Africa the smallest, the only BRICS economy with a GDP lower than US$ 1 trillion. Russia abandoned communism almost 25 years ago, but reversed many of the privatizations of 90’s. China is still ruled by communism, but has a vibrant private sector and recently has officially declared market forces to play a dominant role in its economy. Brazil, Russia and South Africa are global natural resources powerhouses and commodity exporters while China and India are large commodity importers. Brazil is relatively closed to international trade of goods and services, in marked contrast to the other four economies. Brazil, India and South Africa are dependent on external capital flows whereas China and Russia are capital exporters. India and South Africa have younger populations and a large portion living below the poverty line. Despite its extraordinary growth experience that lifted many millions from poverty, China still has 28% of its population classified as poor. Russia and China have much older populations and one of their challenges is to deal with the effects of a declining labor force in the near future. India, China and South Africa face a long way to urbanization, while Brazil and Russia are already urbanized countries. China is an industrial economy but its primary sector still absorbs a large pool of workers. India is not, but the primary sector employs also a large share of the labor force. China’s aggregate demand structure is biased towards investment that has been driving its expansion. Brazil and South Africa have an aggregate demand structure similar to the developed economies, with private consumption accounting for approximately 70%. The same similarity applies to the supply side, as in both economies the share of services nears 70%. The development problem is a productivity problem, so microeconomic reforms are badly needed to foster long-term growth of the BRICS economies since they have lost steam due a variety of factors, but fundamentally due to slower total factor productivity growth. China and India are implementing ambitious reform programs, while Brazil is dealing with macroeconomic disequilibria. Russia and South Africa remain mute about structural reforms. There are some potential benefits to Brazil to be extracted from a greater economic integration with the BRICS, particularly in natural resources intensive industries and services. Necessary conditions to the materialization of those gains are the removal of the several sources of resource misallocation and strong investment in human capital.

Bright minds, big rent: gentrification and the rising returns to skill

In 1980, housing prices in the main US cities rose with distance to the city center. By 2010, that relationship had reversed. We propose that this development can be traced to greater labor supply of high-income households through reduced tolerance for commuting. In a tract-level data set covering the 27 largest US cities, years 1980-2010, we employ a city-level Bartik demand shifter for skilled labor and find support for our hypothesis: full-time skilled workers favor proximity to the city center and their increased presence can account for the observed price changes, notably the rising price premium commanded by centrality.