Studie über die Rolle des Vitamin E als Nitritscavenger und N-Nitrosamine Inhibitor

Study on the Role of Vitamin E as Nitrite Scavenger and N-Nitrosamine Inhibitor N-nitrosamine are known for their powerful carcinogenicity. They may be formed under acidic conditions by interaction of nitrosable amino substrates and nitrosating agents such as nitrite, nitrate and nitroso gases. Several of recent investigations demonstrate that certain micronutrients such as vitamin A, C, and E and trace elements selenium and zinc play an important role in cancer prevention. Because of their strong antioxidative, nitrite scavenging and free radical quenching properties, vitamin C and E are capable of inhibiting the peroxidation and nitrosation reaction. This paper summarizes the research work done up to date in the field of inhibition of N-nitrosamine formation by vitamin E. It also includes the latest results of our in vitro study on the inhibitory influence of vitamin E and a mixture of tocopherols as well as the cumulative effect of vitamin C and E on the formation of N-nitroso-N-methylaniline (NMNA). α-tocopherol and the mixture of tocopherols are capable of reducing nitrite concentration in hydrophilic reaction medium and thus inhibits the formation of N-nitrosamine. Both vitamins together have a stronger nitrite scavenger effect than either of them alone. The results of research work done up to date strongly suggest that both vitamins may play an important role in reducing the health hazard of some carcinogenic N-nitroso compounds.     

Agens Faber: Toward a Theory of Artefacts for MAS

Human intelligence has evolved along with the use of more and more sophisticated tools, allowing Homo Faber (from Homo Habilis to Homo Sapiens Sapiens) to cope with environment changes, as well as to adapt the environment to his needs. Analogously, in this seminal paper we introduce the notion of Agens Faber, conveying the idea that agent intelligence should not be considered as separated by the agent ability to perceive and affect the environment—and so, that agent intelligence is strictly related to the artefacts that enable, mediate and govern any agent (intelligent) activity.

Along this line, we first discuss the notion of artefact for MAS in general, then we try to devise out the admissible / required / desirable features of an artefact for MAS. We elaborate on the many sorts of possible relations between agents and artefacts, focusing in particular on the issue of the rational exploitation of artefacts, and also rough out a possible taxonomy of artefacts for MAS.     

On the impact of physical layer awareness on scheduling and resource allocation in broadband multicellular IEEE 802.16 systems [Radio Resource Management and Protocol Engineering for IEEE 802.16]

Multicellular networks based on the IEEE 802.16 standard appear to be very promising candidates to provide end users with broadband wireless access. However, they also pose interesting challenges in terms of radio resource management, where several design choices are not specified in the standard, intentionally left open to implementors. For this reason, we focus in this article on scheduling and resource allocation, and investigate how they could operate in a cross-layer fashion. In particular, we describe the principles of joint scheduling and resource allocation for IEEE 802.16 operating in AMC mode, and discuss the critical role played by physical layer considerations, especially intercell interference estimation and channel state awareness, in the obtained performance. This leads to identifying key open issues and possible general solutions     

Environment as a first class abstraction in multiagent systems

The current practice in multiagent systems typically associates the environment with resources that are external to agents and their communication infrastructure. Advanced uses of the environment include infrastructures for indirect coordination, such as digital pheromones, or support for governed interaction in electronic institutions. Yet, in general, the notion of environment is not well defined. Functionalities of the environment are often dealt with implicitly or in an ad hoc manner. This is not only poor engineering practice, it also hinders engineers to exploit the full potential of the environment in multiagent systems. In this paper, we put forward the environment as an explicit part of multiagent systems.We give a definition stating that the environment in a multiagent system is a first-class abstraction with dual roles: (1) the environment provides the surrounding conditions for agents to exist, which implies that the environment is an essential part of every multiagent system, and (2) the environment provides an exploitable design abstraction for building multiagent system applications. We discuss the responsibilities of such an environment in multiagent systems and we present a reference model for the environment that can serve as a basis for environment engineering. To illustrate the power of the environment as a design abstraction, we show how the environment is successfully exploited in a real world application. Considering the environment as a first-class abstraction in multiagent systems opens up new horizons for research and development in multiagent systems.     

Maternal depression and early positive parenting predict future conduct problems in young children with attention-deficit/hyperactivity disorder.

Children with attention-deficit/hyperactivity disorder (ADHD) are at risk for adverse outcomes such as substance abuse and criminality, particularly if they develop conduct problems. Little is known about early predictors of the developmental course of conduct problems among children with ADHD, however. Parental psychopathology and parenting were assessed in 108 children who first met Diagnostic and Statistical Manual of Mental Disorders (4th ed.) criteria for ADHD at 4-7 years old. When demographic variables and baseline ADHD and conduct problems were controlled, maternal depression predicted conduct problems 2-8 years following the initial assessment, whereas positive parenting during the structured parent- child interaction task predicted fewer future conduct problems. These findings suggest that maternal depression is a risk factor, whereas early positive parenting is a protective factor, for the developmental course of conduct problems among children with ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nonpathological Lyapunov functions and discontinuous Carathéodory systems

Differential equations with discontinuous right-hand side and solutions intended in Carathéodory sense are considered. For these equations, sufficient conditions which guarantee both Lyapunov stability and asymptotic stability in terms of nonsmooth Lyapunov functions are given. An invariance principle is also proven.     

Biosorption of heavy metals by Saccharomyces cerevisiae: Effects of nutrient conditions

Studies took place to investigate the effects of different nutrient conditions on the biosorption ability and selectivity of heavy metals by Saccharomyces cerevisiae. After having grown in media supplemented with additional glucose, ammonium, phosphate or cysteine, the yeast was exposed to an equimolar solution of lead, cadmium, zinc and copper. Lead removal from a mixed solution was significantly higher than that of copper, followed by zinc and cadmium. Generally, yeasts from cysteine-rich media showed greatest sorption capacity whereas phosphate addition influenced zinc selectivity. In addition, glucose, fructose and sucrose as carbon sources were examined. Cultures grown in glucose had a better uptake than those cultivated with fructose at an incubation time of 30 min.     

Good teaching inputs do not correspond to desired responses in ecological neural networks

In this paper we analyze how supervised learning occurs in ecological neural networks, i.e. networks that interact with an autonomous external environment and, therefore, at least partially determine with their behavior their own input. Using an evolutionary method for selecting good teaching inputs we surprisingly find that to obtain a desired outputX it is better to use a teaching input different fromX. To explain this fact we claim that teaching inputs in ecological networks have two different effects: (a) to reduce the discrepancy between the actual output of the network and the teaching input, (b) to modify the network's behavior and, as a consequence, the network's learning experiences. Evolved teaching inputs appear to represent a compromise between these two needs. We finally show that evolved teaching inputs that are allowed to change during the learning process function differently at different stages of learning, first giving more weight to (b) and, later on, to (a).     

An elementary proof of Sylvester’s double sums for subresultants

In 1853 Sylvester stated and proved an elegant formula that expresses the polynomial subresultants in terms of the roots of the input polynomials. Sylvester’s formula was also recently proved by Lascoux and Pragacz using multi-Schur functions and divided differences. In this paper, we provide an elementary proof that uses only basic properties of matrix multiplication and Vandermonde determinants.