Discrete event simulation as an ergonomic tool to predict workload exposures during systems design

This methodological paper presents a novel approach to predict operator's mechanical exposure and fatigue accumulation in discrete event simulations. A biomechanical model of work-cycle loading is combined with a discrete event simulation model which provides work cycle patterns over the shift resulting in a load-time trace for the entire shift. This trace was tested with four different muscle endurance-recovery model pairs yielding a fatigue-time history for the entire shift. An electronics assembly case with shift-long perceived fatigue data was compared to the simulation model results. Sensitivity testing of the input work-rest ratios found the best correlation (r² = 0.84) at 17% of the modeled rest level. The need for this adjustment is discussed in terms of limitations of available muscle endurance and recovery models. Muscle model limitations notwithstanding, this approach allows system designers to understand the mechanical exposure and fatigue-related effects of proposed alternatives in system design stages and can contribute to ‘Virtual Human Factors’ approaches for pro-active ergonomics capability.     

Cancellous metal implant in the surgical treatment of recurrent post-traumatic shoulder dislocation

After a short abstract about history and principles in the operative treatment of recurrent dislocation of the shoulder joint and after an illustration of disadvantages and complications in the operative technique described by Eden-Hybinette-Lange, which is favoured in the German speaking area, we are introducing a modification of this technique by use of an implant made from cancellous metal "Lübeck" instead of a bone block. In addition to the introduction of this new technique, first results in 14 patients undergoing this operation are shown up.     

Splat-based surface reconstruction from defect-laden point sets

We introduce a method for surface reconstruction from point sets that is able to cope with noise and outliers. First, a splat-based representation is computed from the point set. A robust local 3D RANSAC-based procedure is used to filter the point set for outliers, then a local jet surface – a low-degree surface approximation – is fitted to the inliers. Second, we extract the reconstructed surface in the form of a surface triangle mesh through Delaunay refinement. The Delaunay refinement meshing approach requires computing intersections between line segment queries and the surface to be meshed. In the present case, intersection queries are solved from the set of splats through a 1D RANSAC procedure.     

Production and preliminary characterization of ferritic-martensitic steel T91 cladding tubes for LBE or Pb cooled nuclear systems

Thin wall tubes with suitable dimensions for possible future use as nuclear fuel cladding based on ferritic-martensitic steel T91 have been produced. Several rolling routes for thin wall tube rolling have been successfully explored to produce T91 tubes of 8.5 mm OD and 0.5 mm wall thickness as well as 6.5 mm OD and 0.5 mm wall thickness. The results show that the cold rolled Т91 steel thin walled tubes remain ductile and the material easily carries fractional strains. Finally the microstructure of the resulting tubes was examined and preliminary burst and tensile tests were performed showing properties comparable to those of T91 plate material.     

Central Role of Dendritic Cells in Pulmonary Arterial Hypertension in Human and Mice

The pathogenesis of idiopathic pulmonary arterial hypertension (IPAH) is not fully understood, but evidence is accumulating that immune dysfunction plays a significant role. We previously reported that 31-week-old Tnfaip3^DNGR1-KO mice develop pulmonary hypertension (PH) symptoms. These mice harbor a targeted deletion of the TNFα-induced protein-3 (Tnfaip3) gene, encoding the NF-κB regulatory protein A20, specifically in type I conventional dendritic cells (cDC1s). Here, we studied the involvement of dendritic cells (DCs) in PH in more detail. We found various immune cells, including DCs, in the hearts of Tnfaip3^DNGR1-KO mice, particularly in the right ventricle (RV). Secondly, in young Tnfaip3^DNGR1-KO mice, innate immune activation through airway exposure to toll-like receptor ligands essentially did not result in elevated RV pressures, although we did observe significant RV hypertrophy. Thirdly, PH symptoms in Tnfaip3^DNGR1-KO mice were not enhanced by concomitant mutation of bone morphogenetic protein receptor type 2 (Bmpr2), which is the most affected gene in PAH patients. Finally, in human IPAH lung tissue we found co-localization of DCs and CD8+ T cells, representing the main cell type activated by cDC1s. Taken together, these findings support a unique role of cDC1s in PAH pathogenesis, independent of general immune activation or a mutation in the Bmpr2 gene.     

Comparative study of the consumption of virgin olive oil or seje on lipid profile and oxidation resistance of high density lipoprotein (HDL) of rat plasma

We compared the effect of the consumption of seje oil (Oenocarpus bataua), with that of olive oil, on plasma lipids and susceptibility in vitro to oxidation of high density lipoprotein (HDL) in the rat. Two groups often male Sprague Dawley rats were fed ad libitum, for a lapse of eight week, with a purified diets with 10g de seje oil or olive oil/100 g of diet (GS y GO respectively). The animals were exsanguinated at the end of the experimental after a 14 hour fast. Plasma was isolated by centrifugation, and the fractions of lipoproteins were separated from the plasma by sequential ultracentrifugation. Rats of GO had a statistically significant lower in concentration of TG (p < 0.05) compared with GS group. HDL fractions in both groups were oxidatively modified by incubation with copper ions. Differences in the fractions susceptibilities to peroxidation were studied by measuring the formation of thiobarbituric acid reactive substance (TBARS) for 3 hours. HDL in GS had a statistically significant decrease in TBARS formation (p < 0.05) relative to HDL of GO. This may be explained by the lower concentration of polyunsaturated fatty acids of HDL in GS compared with HDL in GO.     

Modified ferrous oxidation‐xylenol orange method to determine lipid hydroperoxides in fried snacks

A modified ferrous oxidation‐xylenol orange (FOX) method was adapted to measure lipid hydroperoxides (LHP) in lipid extracts from snack foods fried in vegetable oils. First, a methanol‐based FOX reaction medium was assayed, but this became turbid upon addition of the lipid extracts dissolved in ethanol. To avoid the precipitation of lipids, the polarity of the reaction medium was reduced by lowering its water content and by replacing the methanol as the basis of the medium for less polar solvents. Some of the solvents used instead of methanol yielded a lower FOX reaction response. Of the reaction media assayed, the one based on dichloromethane/ethanol (3:2, vol/vol) was not turbid at high lipid extract concentrations (assayed at up to 25 mg of lipid extract/mL reaction medium) and provided the same response level as the methanol‐based medium. Thus, this FOX method shows high sensitivity and is particularly useful for lipid extracts with low LHP content. This method was also successfully applied to edible oils. Solvents such as 2‐propanol, ethyl acetate and butanol were discarded, because they easily produce hydroperoxides, which interfere in the FOX reaction. Xylenol orange preparations from a number of suppliers were tested, and some differences affecting the sensitivity of the reaction were observed.     

Vectorial structure of nonparaxial electromagnetic beams.

A representation of the general solution of the Maxwell equations is proposed in terms of the plane-wave spectrum of the electromagnetic field. In this representation the electric field solution is written as a sum of two terms that are orthogonal to each other at the far field: One is transverse to the propagation axis, and the magnetic field associated with the other is also transverse. The concept of the so-called closest field to a given beam is introduced and applied to the well-known linearly polarized Gaussian beam.     

Group D adenoviruses infect primary central nervous system cells more efficiently than those from group C

Group C adenovirus-mediated gene transfer to central nervous system cells is inefficient. We found that wild-type group D viruses, or recombinant adenovirus type 2 (Ad2) (group C) modified to contain Ad17 (group D) fiber, were more efficient in infecting primary cultures of neurons. Together with studies on primary vascular endothelial cells and tissue culture cell lines, our results indicate that there is not a universally applicable adenovirus serotype for use as a gene transfer vector.     

Estimating the parameters of semiconductor lasers based on weak optical feedback self-mixing interferometry

The paper presents a practical approach for measuring the linewidth enhancement factor /spl alpha/ of semiconductor lasers and the optical feedback level factor C in a semiconductor laser with an external cavity. The proposed approach is based on the analysis of the signals observed in an optical feedback self-mixing interferometric system. The parameters /spl alpha/ and C are estimated using a gradient-based optimization algorithm that achieves best data-to-theoretical model match. The effectiveness and accuracy of the method has been confirmed and tested by computer simulations and experiments, which show that the proposed approach is able to estimate /spl alpha/ and C with an accuracy of 6.7% and 4.63%, respectively.