Three-dimensional anatomy of equine incisors : tooth length, enamel cover and age related changes

BACKGROUND:Equine incisors are subjected to continuous occlusal wear causing multiple, age related changes of the extragingival crown. It is assumed that the occlusal wear is compensated by continued tooth elongation at the apical ends of the teeth. In this study, muCT-datasets offered the opportunity to analyze the three-dimensional appearance of the extra- and intraalveolar parts of the enamel containing dental crown as well as of the enamel-free dental root. Multiple morphometric measurements elucidated age related, morphological changes within the intraalveolar part of the incisors. RESULTS:Equine incisors possess a unique enamel cover displaying large indentations on the mesial and distal sides. After eruption tooth elongation at the apical end outbalances occlusal wear for two to four years resulting in increasing incisor length in this period of time. Remarkably, this maximum length is maintained for about ten years, up to a tooth age of 13 to 15years post eruption. Variances in the total length of individual teeth are related to different Triadan positions (central-, middle- and corner incisors) as well as to the upper and lower arcades. CONCLUSION:Equine incisors are able to fully compensate occlusal wear for a limited period of time. However, after this ability ceases, it is expected that a diminished intraalveolar tooth length will cause massive changes in periodontal biomechanics. The time point of these morphodynamic and biomechanical changes (13 to 15years post eruption) occurs in coincidence with the onset of a recently described destructive disease of equine incisor (equine odontoclastic tooth resorption and hypercementosis) in aged horses. However, further biomechanical, cell biological and microbiological investigations are needed to elucidate a correlation between age related changes of incisor morphology and this disease

Brennpunkt Afghanistan

Versuch einer historischen, geopolitischen, geostrategischen, militärpolitischen Erklärung des Afghanistan-Krieges. Argumente zur Sinnlosigkeit einer militärischen Problemlösung und zum Übergang zu einer politischen Regelung.:Autorenbeiträge: Hermann Hagena, Afghanistan: ein sinnloser Krieg? Arne C. Seifert, Den Krieg in Afghanistan beenden und sofort zu einer politischen Lösung übergehen. Redaktioneller Anhang: Übersichten, Karten; Bild- und Kartennachweise; Über die Autoren; Aktuelle Afghanistan-Dokumente und -Publikationen (Auswahl)

Axonal Transport, Phase-Separated Compartments, and Neuron Mechanics - A New Approach to Investigate Neurodegenerative Diseases

Many molecular and cellular pathogenic mechanisms of neurodegenerative diseases have been revealed. However, it is unclear what role a putatively impaired neuronal transport with respect to altered mechanical properties of neurons play in the initiation and progression of such diseases. The biochemical aspects of intracellular axonal transport, which is important for molecular movements through the cytoplasm, e.g., mitochondrial movement, has already been studied. Interestingly, transport deficiencies are associated with the emergence of the affliction and potentially linked to disease transmission. Transport along the axon depends on the normal function of the neuronal cytoskeleton, which is also a major contributor to neuronal mechanical properties. By contrast, little attention has been paid to the mechanical properties of neurons and axons impaired by neurodegeneration, and of membraneless, phase-separated organelles such as stress granules (SGs) within neurons. Mechanical changes may indicate cytoskeleton reorganization and function, and thus give information about the transport and other system impairment. Nowadays, several techniques to investigate cellular mechanical properties are available. In this review, we discuss how select biophysical methods to probe material properties could contribute to the general understanding of mechanisms underlying neurodegenerative diseases

Brennpunkt Afghanistan

Versuch einer historischen, geopolitischen, geostrategischen, militärpolitischen Erklärung des Afghanistan-Krieges. Argumente zur Sinnlosigkeit einer militärischen Problemlösung und zum Übergang zu einer politischen Regelung.:Autorenbeiträge: Hermann Hagena, Afghanistan: ein sinnloser Krieg? Arne C. Seifert, Den Krieg in Afghanistan beenden und sofort zu einer politischen Lösung übergehen. Redaktioneller Anhang: Übersichten, Karten; Bild- und Kartennachweise; Über die Autoren; Aktuelle Afghanistan-Dokumente und -Publikationen (Auswahl)

Electronic Properties of TiO2_2 Nanotubes

quasi-one-dimensional (1D) titania nanostructures - single-walled nanotubes formed by rolling [101] planes of TiO$_2$ (anatase phase) are modeled and their electronic properties and bond orders indices are studied using the tight-binding band theory. We show that all zigzag (n,0)- and armchair (n,n)-like nanotubes are uniformly semiconducting, and the band gap trends to vanish as the tube diameters decrease. It was established that the zigzag (n,0) nanotubes configurations are more likely to form when the diameters are larger 1 nm. The Ti-O covalent bonds were found to be the strongest interactions in TiO$_2$ tubes, whereas Ti-Ti bonds proved to be much weaker.Comment: 7 pages, 4 figure

Time-dependent probability density function in cubic stochastic processes

We report time-dependent Probability Density Functions (PDFs) for a nonlinear stochastic process with a cubic force by novel analytical and computational studies. Analytically, a transition probability is formulated by using a path integral and is computed by the saddle-point solution (instanton method) and a new nonlinear transformation of time. The predicted PDF p(x, t) is in general given as a time integral and useful PDFs with explicit dependence on x and t are presented in certain limits (e.g. in the short and long time limits). Numerical simulations of the FokkerPlanck equation provide exact time evolution of the PDFs and confirm analytical predictions in the limit of weak noise. In particular, we show that non-equilibrium PDFs behave drastically differently from the stationary PDFs in regards to the asymmetry (skewness) and kurtosis. Specifically, while stationary PDFs are symmetric, transient PDFs are skewed; transient PDFs are much broader than stationary PDFs, with the kurtosis larger and smaller than 3, respectively. We elucidate the effect of nonlinear interaction on the strong fluctuations and intermittency in relaxation process

Calculation of partial isotope incorporation into peptides measured by mass spectrometry

<p>Abstract</p> <p>Background</p> <p>Stable isotope probing (SIP) technique was developed to link function, structure and activity of microbial cultures metabolizing carbon and nitrogen containing substrates to synthesize their biomass. Currently, available methods are restricted solely to the estimation of fully saturated heavy stable isotope incorporation and convenient methods with sufficient accuracy are still missing. However in order to track carbon fluxes in microbial communities new methods are required that allow the calculation of partial incorporation into biomolecules.</p> <p>Results</p> <p>In this study, we use the characteristics of the so-called 'half decimal place rule' (HDPR) in order to accurately calculate the partial¹³C incorporation in peptides from enzymatic digested proteins. Due to the clade-crossing universality of proteins within bacteria, any available high-resolution mass spectrometry generated dataset consisting of tryptically-digested peptides can be used as reference.</p> <p>We used a freely available peptide mass dataset from <it>Mycobacterium tuberculosis </it>consisting of 315,579 entries. From this the error of estimated versus known heavy stable isotope incorporation from an increasing number of randomly drawn peptide sub-samples (100 times each; no repetition) was calculated. To acquire an estimated incorporation error of less than 5 atom %, about 100 peptide masses were needed. Finally, for testing the general applicability of our method, peptide masses of tryptically digested proteins from <it>Pseudomonas putida </it>ML2 grown on labeled substrate of various known concentrations were used and¹³C isotopic incorporation was successfully predicted. An easy-to-use script <abbrgrp><abbr bid="B1">1</abbr></abbrgrp> was further developed to guide users through the calculation procedure for their own data series.</p> <p>Conclusion</p> <p>Our method is valuable for estimating¹³C incorporation into peptides/proteins accurately and with high sensitivity. Generally, our method holds promise for wider applications in qualitative and especially quantitative proteomics.</p

A Perspective on Implementing Movement Sonification to Influence Movement (and Eventually Cognitive) Creativity

Creativity represents an important feature in a variety of daily-life and domain-specific contexts. Recent evidence indicates that physical movement serves as a key resource for exploring and generating task-relevant creative ideas, supporting the embodied perspective on creative cognition. An intuitive link between movement and creative cognition is movement creativity. The process of exploring the movement solutions an environment offers (i.e., affordances) and exploiting novel, functional, and creative movements may translate to and improve how individuals explore and generate novel ideas. Opening perception to the variety of affordances (“conventional” and novel) an environment offers drives creative movement. Teachers and coaches can promote this process by designing a learning environment that invites performers to consider and utilize novel movement solutions. In this article, we present a rationale for using movement sonification to promote creative movement. Movement sonification consists of mapping a movement parameter into sound, with a sound being triggered or changing according to how movement unfolds. We argue that movement sonification can facilitate the emergence of creative movement via enhancing perception of currently performed movements and invite performers to utilize novel affordances, and emphasizing information for regulating subsequent creative actions. We exemplify this concept in a creative dance intervention for children during physical education classes. In conclusion, we contend that learning to explore original dance sequences using movement sonification may provide a meaningful link between creative movement and creative cognition. Children may use their minds and bodies as tools for creative thinking and exploration, such as shaping letters with their bodies

A new clinico-pathological classification system for mesial temporal sclerosis

We propose a histopathological classification system for hippocampal cell loss in patients suffering from mesial temporal lobe epilepsies (MTLE). One hundred and seventy-eight surgically resected specimens were microscopically examined with respect to neuronal cell loss in hippocampal subfields CA1–CA4 and dentate gyrus. Five distinct patterns were recognized within a consecutive cohort of anatomically well-preserved surgical specimens. The first group comprised hippocampi with neuronal cell densities not significantly different from age matched autopsy controls [no mesial temporal sclerosis (no MTS); n = 34, 19%]. A classical pattern with severe cell loss in CA1 and moderate neuronal loss in all other subfields excluding CA2 was observed in 33 cases (19%), whereas the vast majority of cases showed extensive neuronal cell loss in all hippocampal subfields (n = 94, 53%). Due to considerable similarities of neuronal cell loss patterns and clinical histories, we designated these two groups as MTS type 1a and 1b, respectively. We further distinguished two atypical variants characterized either by severe neuronal loss restricted to sector CA1 (MTS type 2; n = 10, 6%) or to the hilar region (MTS type 3, n = 7, 4%). Correlation with clinical data pointed to an early age of initial precipitating injury (IPI < 3 years) as important predictor of hippocampal pathology, i.e. MTS type 1a and 1b. In MTS type 2, IPIs were documented at a later age (mean 6 years), whereas in MTS type 3 and normal appearing hippocampus (no MTS) the first event appeared beyond the age of 13 and 16 years, respectively. In addition, postsurgical outcome was significantly worse in atypical MTS, especially MTS type 3 with only 28% of patients having seizure relief after 1-year follow-up period, compared to successful seizure control in MTS types 1a and 1b (72 and 73%). Our classification system appears suitable for stratifying the clinically heterogeneous group of MTLE patients also with respect to postsurgical outcome studies