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Natural Functions (natural + function)
Selected AbstractsAntero-posterior activity changes in the superficial masseter muscle after exposure to experimental painEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2002Jens C. Türp The aim of this randomized, controlled, double-blind study was to examine how the activation pattern of the masseter muscle changes during natural function when experimental pain is induced in a discrete anterior area of the muscle. In 20 subjects, three bipolar surface electrodes and three intramuscular fine-wire electrodes (antero-posterior mapping) were simultaneously attached above and in the right masseter muscle to record the electromyographic (EMG) activity during unilateral chewing before and after infusion of a 0.9% isotonic and 5% hypertonic saline bolus in the anterior area of the muscle. The activity of the contralateral masseter muscle was registered by surface electrodes. In addition, the development of pain intensity was quantitatively measured with a numerical rating scale (NRS). While both saline concentrations caused pain, the hypertonic solution evoked stronger pain. The experiments also provided evidence of a significant although differential activity reduction of the ipsilateral masseter muscle in the antero-posterior direction. The activity reduction decreased with increasing distance from the location of the infusion. The results support the idea that the strategy of differential activation protects the injured muscle while simultaneously maintaining optimal function. [source] Integrating Hume's Accounts of Belief and JustificationPHILOSOPHY AND PHENOMENOLOGICAL RESEARCH, Issue 2 2001LOUIS E. LOEB Hume's claim that a state is a belief is often intertwined,though without his remarking on this fact,with epistemic approval of the state. This requires explanation. Beliefs, in Hume's view, are steady dispositions (not lively ideas), nature's provision for a steady influence on the will and action. Hume's epistemic distinctions call attention to circumstances in which the presence of conflicting beliefs undermine a belief's influence and thereby its natural function. On one version of this interpretation, to say that a belief is justified, ceteris paribus, is to say that for all that has been shown the belief would be steady in its influence under suitable reflection. On a second version, it is to say that prima facie justification is an intrinsic property of the state, in virtue of its steadiness. These versions generate different understandings of the relationship between Parts iii and iv of Book I of the Treatise. [source] The future: genes, physical activity and healthACTA PHYSIOLOGICA, Issue 4 2010F. W. Booth Abstract The assigned title for the Lindhard presentation was to examine the future of genes, physical activity and health. The current review is a summary of this presentation. Caution is expressed that technology is improving so rapidly that a future view is limited to a few years as opposed to the 100 years passing since Lindhard's achievements. The near futuristic opportunities and challenges for four major topic topics are reviewed here. Concerns are expressed over current usage of the terms ,control' group and ,non-responders' in exercise research. Our view is that ,control' needs to be differentiated between its usage for treatments of exercise to restore natural functions in individuals with less than healthy levels of physical activity and the inherited genome's expectation for physical activity levels to maintain normal function. For the second discussed topic, it is proposed that the term ,non-responders' should be replaced by the term ,low sensitivity' as there may be no such human who is a non-responder to every exercise adaptation. The third futuristic topic is exercise prescription as envisioned for individualized medicine. However, numerous limitations and challenges exist to truly optimal exercise medicine at the level of one individual. Finally, preventative physical activity medicine is discussed. Physical activity as a therapy now exists to prevent most of the chronic diseases. The future needs to understand the molecular basis for how the body becomes dysfunctional when its level of physical activity does not match the norm of physical activity that selected our inherited genome. [source] Responses of riparian plants to flooding in free-flowing and regulated boreal rivers: an experimental studyJOURNAL OF APPLIED ECOLOGY, Issue 6 2002M. E. Johansson Summary 1The long history of river regulation has resulted in extensively changed ecosystem structures and processes in rivers and their associated environments. This fact, together with changing climatic and hydrological conditions, has increased the need to recover the natural functions of rivers. To develop guidelines for river restoration, comparative ecological experiments at contrasting water-level regimes are needed. We compared growth and survival of transplanted individuals of four riparian plant species (Betula pubescens, Carex acuta, Filipendula ulmaria and Leontodon autumnalis) over 2 years on four free-flowing and four regulated riverbank sites in northern Sweden. The species were chosen as representatives of dominating life-forms and species traits on different elevations of the riverbanks. 2In Betula and Filipendula, mean proportional growth rates were significantly higher at free-flowing sites than at regulated sites, whereas no consistent differences between free-flowing and regulated sites were found in Carex and Leontodon. Differences among species were generally in accordance with natural distribution patterns along riverbank elevation gradients and with experimental evidence on flooding tolerance, although plants of all species survived and even showed positive growth rates on elevations below their natural range of occurrence. 3Partial least squares regression was used to relate plant performance (growth and survival) to duration, frequency and timing of flooding at the different sites. Flood duration and frequency typically reduced performance in all species and during all time periods, although to various degrees. Flood events early in the experiment determined the outcome to a high degree at all sites. Variables indicating a regulated regime were mostly negatively related to plant performance, whereas free-flowing regime variables were positively related to plant performance. 4We used two of the regression models generated from our data with an acceptably high predictive power to simulate a hypothetical re-regulation scenario in run-of-river impoundments. With an overall reduction in flooding duration and frequency of 50,75%, plant performance of Filipendula at low riverbank elevations showed predicted increases of about 20,30%, levelling off to zero at the highest elevations. Reductions in summer floods represented about one-third to half of this increase. 5We conclude that for a range of species individual plant performance is clearly reduced on banks of impoundments and storage reservoirs due to changes in the water-level regime. Furthermore, our model simulation suggests that rather substantial reductions of flood duration and frequency are needed to improve plant performance on riverbanks upstream from dams in impounded rivers. River restoration principles should, however, be based on a combination of experimental data on plant performance of individual species and observed long-term changes in plant communities of regulated rivers. Consequently, successful re-regulation schemes in boreal rivers should include both reductions of summer and winter floods as well as re-introduced spring floods. [source] Biochemische Interaktionen in Marinen Biofilmen.CHEMIE IN UNSERER ZEIT (CHIUZ), Issue 3 2009Kampf, Kommunikation, Kooperation Abstract Marine Mikroorganismen sind als vielseitige Produzenten von Sekundärmetaboliten bekannt. Auch wenn das Meer tausende von bioaktiven Metaboliten in den letzten zwei Jahrzehnten hervorgebracht hat, so stehen wir erst am Anfang, die natürlichen Funktionen dieser Moleküle zu erforschen. Viele Mikroorganismen kommen in der Umwelt als mehrzellige Lebensgemeinschaften, so genannten Biofilmen, vor. Dabei stellt die chemische Kommunikation einen wichtigen Mechanismus dar, wie Biofilmpopulationen ihre Verhaltensweisen koordinieren und auf Umweltveränderungen reagieren. Aktuelle Untersuchungen bringen ein komplexes Netz biochemischer Wechselbeziehungen ans Licht, über das mikrobielle Symbiosen, Konkurrenz und Verteidigung gegenüber Fraßfeinden und Parasiten vermittelt wird. Das Verstehen der molekularen Grundlagen von Biofilminteraktionen in ihrem ökologischen Kontext birgt das Potential, die Suche nach wirkspezifischen Naturstoffen und die Entwicklung von Biofilm-basierter Biotechnologien zu verfeinern. Marine microorganisms are versatile producers of secondary metabolites. Although the sea has yielded thousands of bioactive metabolites over the past two decades, we are only beginning to explore the natural functions of these molecules. Many microorganisms exist in the environment as multicellular communities, so-called biofilms. Chemical communication is an essential part of the way in which biofilm populations coordinate their behavior and respond to environmental challenges. Recent research has been unravelling a complex web of chemical crosstalk mediating microbial symbiosis, competition and defense against predators and pathogens. Understanding the molecular basis of biofilm interactions in their ecological context bears the potential of refining natural product discovery and the development of biofilm-derived biotechnologies. [source] | ||||||||||