A chamber for biomechanical,electrochemical and electrophysiological measurements in functional segments of peripheral nerves

The aim of the work was to develop the chamber to be used in biomechanical, electrochemical and electrophysiological measurements in functional segments of peripheral nerves, when electrical stimulating pulses are selectively applied to preselected locations along the nerve and neural responses are measured.     

Robustness as a criterion for use of hollow clay masonry units in seismic zones: an attempt to propose the measure

In order to provide adequate seismic behavior of masonry walls, local brittle failure of masonry units in the most stressed zones of structural walls should be prevented. Although robust behavior is required by the code, no specifications are given regarding the criteria to fulfill this requirement. To propose such criteria, a series of 28 masonry walls, built with six different types of hollow clay masonry units, currently available on the market, have been tested by subjecting them to cyclic lateral load at two levels of constant precompression. Besides, the strength characteristics of the units, like compressive strength orthogonal and parallel to the bed joints and tensile and shear strength of the units have been determined by standardized and specifically designed testing procedures. By correlating the parameters of seismic resistance of the walls and strength characteristics of the units, no specific indicator for robustness could have been determined on the basis of the mechanical characteristics of the tested units. It has been found that in all cases the level of precompression, i.e. the ratio between the compressive stresses in the walls and the compressive strength of masonry, represents the governing parameter.     

The control of the diameter and length of α-MnO2 nanorods by regulation of reaction parameters and their thermogravimetric properties

α-MnO₂-type single-crystal nanorods were synthesized under hydrothermal conditions based on the redox reaction of KMnO₄ in an acidic environment. Several reaction parameters, like the reaction temperature, the reaction time and the concentration of KMnO₄ in the reaction mixture, were varied in order to determine their impact on the structure, the dimensions of the synthesized nanorods, and as well on their thermogravimetric properties. It was found that the reaction time has no significant influence on the diameter, although it has a strong influence on the length of the obtained nanorods. On the other hand, the concentration of KMnO₄ in the reaction mixture has a strong impact on both the diameter and the length. With an increasing concentration of KMnO₄ in the reaction mixture the average lengths and diameters of the isolated MnO₂ nanorods are reduced. The change in dimensions of the synthesized nanorods is reflected in their thermogravimetric properties.     

Effect of alterations in blood volume on cardiac function during maximal exercise

Recently, we proposed that the higher stroke volume (SV) and cardiac output (Q) of endurance-trained (ETR) versus untrained (UTR) individuals are attributable primarily to the enhanced diastolic filling of ETR consequent to a larger blood volume (BV). To test this hypothesis, we examined the effects of manipulating BV on the cardiac function of six ETR and six UTR males. Both groups were examined in the control BV condition (BVctl), then ETR were examined immediately following a 500 mL reduction in BV (BVred) and UTR were examined immediately following a 500 mL expansion of BV (BVexp). In BVctl, compared with UTR, ETR had significantly greater BV (16%), maximal diastolic filling rate (47.4%), maximal ventricular emptying rate (24.6%), SVmax (31.6%), Qmax (29%) and VO2max (54.5%). Following BVexp in UTR, there were immediate significant increases in maximal diastolic filling rate (22.5%), SVmax (9.1%), Qmax (8.9%), and VO2max (12.7%). Following BVred in ETR there were immediate significant decreases in maximal diastolic filling rate (27%), SVmax (14.3%), Qmax (14.7%), and VO2max (7.0%). Maximal systolic emptying rate did not change significantly following BVred or BVexp. We conclude that changes in SV and Q consequent to alterations in BV are attributable primarily to changes in diastolic function, and the majority of the higher diastolic filling rate of ETR is due to their larger BV.     

On the Comparison of Proof Planning Systems: , Ωmega and IsaPlanner

We present a framework for describing proof planners. This framework is based around a decomposition of proof planners into planning states, proof language, proof plans, proof methods, proof revision, proof control and planning algorithms.We use this framework to motivate the comparison of three recent proof planning systems, λCLaM, Ωmega and IsaPlanner, and demonstrate how the framework allows us to discuss and illustrate both their similarities and differences in a consistent fashion. This analysis reveals that proof control and the use of contextual information in planning states are key areas in need of further investigation.     

Determination of macronutrients and some essential elements in the slovene military diet

The energy and nutrient values for military nutrition are defined in the nutritional recommendations of the Slovene Armed Forces. In this study 35 daily military diets sampled in the years 2002 and 2005 by the double basket method were analysed, for energy, total fat, protein, dietary fibre and the elements Ca, Mg, Na, P, K, Fe, Zn, Cu, I and Se. The daily diets were collected at different locations in Slovenia. The aim was to establish whether energy value, content of fat, protein, dietary fibre and selected essential elements are in compliance with the nutritional recommendations of the Slovene Armed Forces. The results indicate that daily intake of essential elements from military meals was sufficient, with the exception of Ca and Zn in diets sampled in 2005. The study was the first in Slovenia analysing daily intakes of essential elements in an adult population aged 19–27 years.     

On Automating Diagrammatic Proofs of Arithmetic Arguments

Theorems in automated theorem proving are usually proved by formal logical proofs. However, there is a subset of problems which humans can prove by the use of geometric operations on diagrams, so called diagrammatic proofs. Insight is often more clearly perceived in these proofs than in the corresponding algebraic proofs; they capture an intuitive notion of truthfulness that humans find easy to see and understand. We are investigating and automating such diagrammatic reasoning about mathematical theorems. Concrete, rather than general diagrams are used to prove particular concrete instances of the universally quantified theorem. The diagrammatic proof is captured by the use of geometric operations on the diagram. These operations are the inference steps of the proof. An abstracted schematic proof of the universally quantified theorem is induced from these proof instances. The constructive -rule provides the mathematical basis for this step from schematic proofs to theoremhood. In this way we avoid the difficulty of treating a general case in a diagram. One method of confirming that the abstraction of the schematic proof from the proof instances is sound is proving the correctness of schematic proofs in the meta-theory of diagrams. These ideas have been implemented in the system, called Diamond, which is presented here.     

Functionalization of sodium titanate nanoribbons with silanes and their use in the reinforcement of epoxy nanocomposites

This paper reports on the surface functionalization of sodium titanate nanoribbons (NaTiNRs) with four different silane coupling agents: 3‐(aminopropyl)tri‐ethoxysilane, triethoxyoctylsilane, 3‐glycidyloxypropyltrimethoxysilane, and 3‐aminopropylmethyl diethoxysilane. The functionalized NaTiNRs were used to prepare epoxy‐based nanocomposites with three different wt% of nanofillers (1, 2 and 3 wt% per epoxy). The properties of the prepared nanocomposites were then compared with the pure epoxy resin. The functionalized NaTiNRs, as well as the epoxy and prepared nanocomposites, were characterized using Fourier‐transform infrared spectroscopy, simultaneous differential scanning calorimetry‐thermogravimetric analysis (DSC‐TGA), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and dynamic mechanical analysis. The SEM results showed that the 2‐ and 3‐functional silanes are not the best choice for the modification as they glue the NaTiNRs together into clusters. As a consequence, the glass‐transition temperatures and the mechanical properties are not strongly influenced by the addition of functionalized NaTiNRs. Nevertheless, the influence of the type of silane can be observed. Furthermore, the thermal stability of the prepared nanocomposites increases with the increased loading of the functionalized NaTiNRs. POLYM. COMPOS. 34:1382–1388, 2013. © 2013 Society of Plastics Engineers     

Structural and mechanical properties of polystyrene nanocomposites with 1D titanate nanostructures prepared by an extrusion process

Polystyrene (PS) nanocomposites with titanate nanotubes and titanate nanoribbons were prepared by an extrusion process at 180°C. Nanocomposites with 1 wt% of nanofillers and pure PS that had also been exposed to the extrusion process were comparatively examined with scanning electron microscopy (SEM), electron dispersive X‐ray spectrometry (EDS) mapping, solid state proton nuclear magnetic resonance measurements (¹H NMR), tensile tests, and shear creep measurements. SEM images and EDS mapping analysis show that titanate nanoribbons homogeneously distribute at a micrometer length‐scale in the PS matrix during the extrusion process. This is not the case for titanate nanotubes, which show a stronger tendency to form clusters. Solid state ¹H NMR studies, however, proved that the nanocomposites are inhomogeneous at a nanometric scale where structural components with highly mobile PS molecules coexist with domains of rigid PS molecules. Differences in the ¹H spin‐lattice relaxation at and above the glass transition temperature T_g = 373 K suggest that nanofillers affect the thermodynamic properties of nanocomposite domains. Only a slight increase in mechanical tensile properties was observed in the case of the nanocomposite containing 1 wt% of titanate nanoribbons (TiNRs) probably reflecting a weak interaction between the polymer matrix and the nanofiller. Nevertheless, our results prove that the use of functionalized TiNRs may, in combination with the extrusion process, represent a very promising starting point for the preparation of TiNR nanocomposites at the industrial level. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers