Vacuum fluctuations of a scalar field near a reflecting boundary and their effects on the motion of a test particle

The contribution from quantum vacuum fluctuations of a real massless scalar field to the motion of a test particle that interacts with the field in the presence of a perfectly reflecting flat boundary is here investigated. There is no quantum induced dispersions on the motion of the particle when it is alone in the empty space. However, when a reflecting wall is introduced, dispersions occur with magnitude dependent on how fast the system evolves between the two scenarios. A possible way of implementing this process would be by means of an idealized sudden switching, for which the transition occurs instantaneously. Although the sudden process is a simple and mathematically convenient idealization it brings some divergences to the results, particularly at a time corresponding to a round trip of a light signal between the particle and the wall. It is shown that the use of smooth switching functions, besides regularizing such divergences, enables us to better understand the behavior of the quantum dispersions induced on the motion of the particle. Furthermore, the action of modifying the vacuum state of the system leads to a change in the particle energy that depends on how fast the transition between these states is implemented. Possible implications of these results to the similar case of an electric charge near a perfectly conducting wall are discussed.Comment: 17 pages, 8 figure

SP-Sephadex equilibrium chromatography of bradykinin and related peptides: Application to trypsin-treated human plasma

An analytical method is deseribed for the separation of bradykinin, Lys-bradykinin, and Met-Lys-bradykinin by equilibrium chromatography on SP-Sephadex C-25 eluted in 0.02 Tris-HCl buffer, pH 8.10, 0.12 NaCl. A second elution buffer, 0.02 Tris-HCl buffer, pH 7.70, 0.06 NaCl, serves as a second parameter for the identification of bradykinin and also separates the hormone from plasma bradykinin-potentiating peptides. Ten to one-hundred nanomoles of each peptide can be recovered in high yields, identified by elution position, and measured by bioassay with the isolated guinea pig ileum. The identification of bradykinin as the peptide released by trypsin acting on acid-denatured plasma is documented as an illustration of the method

Redox signaling, Nox5 and vascular remodeling in hypertension

Purpose of review: Extensive data indicate a role for reactive oxygen species (ROS) and redox signaling in vascular damage in hypertension. However, molecular mechanisms underlying these processes remain unclear, but oxidative post-translational modification of vascular proteins is critical. This review discusses how proteins are oxidatively modified and how redox signaling influences vascular smooth muscle cell growth and vascular remodeling in hypertension. We also highlight Nox5 as a novel vascular ROS-generating oxidase. Recent findings: Oxidative stress in hypertension leads to oxidative imbalance that affects vascular cell function through redox signaling. Many Nox isoforms produce ROS in the vascular wall, and recent findings show that Nox5 may be important in humans. ROS regulate signaling by numerous processes including cysteine oxidative post-translational modification such as S-nitrosylation, S-glutathionylation and sulfydration. In vascular smooth muscle cells, this influences cellular responses to oxidative stimuli promoting changes from a contractile to a proliferative phenotype. Summary: In hypertension, Nox-induced ROS production is increased, leading to perturbed redox signaling through oxidative modifications of vascular proteins. This influences mitogenic signaling and cell cycle regulation, leading to altered cell growth and vascular remodeling in hypertension

Alternativas inovadoras para otimizar a transferência de tecnologia para a agricultura familiar.

Editado por Flávio Augusto Portela Santos, José Carlos de Moura, Vidal Pedroso de Faria

Pim processo inovador na cadeia produtiva da maçã brasileira.

A cadeia produtiva da maçã brasileira com a implementação da Produção Integrada de Maçã demonstrou suas preocupações com as necessidades apresentadas pelo mercado consumidor e, além disso, com essa implementação ratifica o papel de segmento pioneiro em inovação no agronegócio brasileiro. O estudo teve como objetivo descrever a implementação da Produção Integrada de Maçã, além de fazer um levantamento a partir das referências sobre inovação e das entrevistas com especialistas do setor se esta implementação pode ser considerada um processo de inovação interativo. Através das entrevistas realizadas com os especialistas da cadeia que participaram da implementação da Produção Integrada de Maçã, bem como de consulta a arquivos da EMBRAPA Uva e Vinho e da Associação Brasileira dos Produtores de Maçã é que este estudo foi efetivado. Após a análise da coleta de dados foi possível a identificação de que existe a presença dos passos descritos na literatura para a identificação da implementação da Produção Integrada de Maçã como um modelo interativo de inovação, cujo centro é a empresa, combinando interações com outra empresa, ou em um segmento entre as empresas individualmente e o sistema de ciência e tecnologia. Por fim, foi possível perceber também que a implementação da Produção Integrada de Maçã foi mais um exemplo de processo inovador realizado pela cadeia produtiva da maçã.SEMEAD