WIRELESS INSOLES TO MEASURE GROUND REACTION FORCES: STEP-BYSTEP VALIDITY IN HOPPING, WALKING, AND RUNNING

This investigation assessed the validity of force measurements from wireless shoe insoles against a force plate and an instrumented treadmill. Thirteen subjects performed hopping tasks on a force plate and walked and ran on an instrumented treadmill while wearing the insoles. Ground reaction forces were measured with the two systems and analyzed perstep and per-hop to assess the accuracy and validity of the insoles. Peak force, contact time, and impulse were calculated for each step, and peak force for each hop. Across all measures, the insoles demonstrated high agreement with the force plate and the treadmill. Intraclass correlation coefficients ranged from 0.81-0.96. The wireless insoles appear to be a valid tool for ground reaction force measurement, and current results support the use of these devices for biomechanical studies outside the laboratory and in the field

Mapping the Biomechanical Properties of Human Knee Cartilage.

Knee osteoarthritis is one of the most common musculoskeletal pathologies. With no cure other than total joint replacement, and the incidence of osteoarthritis rising worldwide, the need to understand how the disease develops has reached a critical level. Alterations in the spatial loading pattern on the joint’s articular cartilage, for example, due to knee injury, have been hypothesized to trigger the onset of the disease. The theory presupposes that the mechanical properties of knee cartilage are non-uniform such that the underlying cartilage is unable to sustain the abnormal loading pattern and deteriorates. However, this tenet is challenging to test directly, in part because it requires detailed knowledge of spatial mechanical properties of the cartilage, which is currently unknown. Therefore, this dissertation sought to address current knowledge gaps by mapping the elastic modulus of healthy human knee articular cartilage across the joint surface. This work represented the first such mapping with fine spatial resolution and employing a physiologically relevant compressive strain rate. Significant variations in modulus were found across the femur and tibial cartilage. Moreover, these variations conformed to a consistent regional pattern across knees, which has not previously been demonstrated. These findings subsequently motivated the development of a constitutive relation that could successfully simulate spatially dependent, high strain rate mechanics. A transversely isotropic hyperelastic model was developed and compared with isotropic hyperelastic models to determine which constitutive relation best represented the natural cartilage mechanics. The transversely isotropic model replicated the spatial mechanical dependence of the tissue through variations in a single model parameter. The model is mechanistic, has a structure and parameters that are analogous to human cartilage physiology, is computationally efficient, and is straightforward to implement in commercial finite element packages. The transversely isotropic model, therefore, represents a novel method for implementing the non-uniform mechanics of knee cartilage that are critical to understanding the initiation and progression of knee osteoarthritis. The characterization of regional mechanical properties of human knee cartilage performed herein has contributed essential baseline knowledge that will fundamentally advance experimental and computational studies of knee osteoarthritis development toward widespread prevention of this devastating disease.PHDKinesiology and Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/99834/1/jmden_1.pd

Households, consumption and the development of medical carein the Netherlands, 1650-1900

This article examines the development of the Dutch medical marketplace between 1650 and 1900 from a household’s perspective. Using debts for medical care recorded in probate inventories, we construct the first quantitative analysis of levels of demand for medical care and the types of medical provision in small towns and villages across the Netherlands – locations much more representative of most of Europe than its better-studied cities. We reveal substantial growth in the sick’s reliance on commercial medical practitioners between 1650 and 1800, measured by both the frequency and size of debts to practitioners. We also find large differences between the commercialised maritime areas of the Netherlands and the more autarchic inland regions, where households were particularly unlikely to have used medical practitioners circa 1650. These differences extended to the types of practitioner involved: surgeons were most prominent in the maritime region; apothecaries in the inland region. Patterns of medical consumption converged during the nineteenth century, as did the types of practitioner used, anticipating laws restricting professional activity in medicine. As we show, differences in households’ uses of medical care within and between regions reflected their income, level of monetisation and engagement in commercial activities and other forms of non-essential consumption. We conclude that the profound growth in commercial medicine experienced in the early modern Netherlands was linked closely to wider trends in consumer behaviour

Nearby transposable elements impact plant stress gene regulatory networks : a meta-analysis in A. thaliana and S. lycopersicum

BACKGROUND: Transposable elements (TE) make up a large portion of many plant genomes and are playing innovative roles in genome evolution. Several TEs can contribute to gene regulation by influencing expression of nearby genes as stress-responsive regulatory motifs. To delineate TE-mediated plant stress regulatory networks, we took a 2-step computational approach consisting of identifying TEs in the proximity of stress-responsive genes, followed by searching for cis-regulatory motifs in these TE sequences and linking them to known regulatory factors. Through a systematic meta-analysis of RNA-seq expression profiles and genome annotations, we investigated the relation between the presence of TE superfamilies upstream, downstream or within introns of nearby genes and the differential expression of these genes in various stress conditions in the TE-poor Arabidopsis thaliana and the TE-rich Solanum lycopersicum. RESULTS: We found that stress conditions frequently expressed genes having members of various TE superfamilies in their genomic proximity, such as SINE upon proteotoxic stress and Copia and Gypsy upon heat stress in A. thaliana, and EPRV and hAT upon infection, and Harbinger, LINE and Retrotransposon upon light stress in S. lycopersicum. These stress-specific gene-proximal TEs were mostly located within introns and more detected near upregulated than downregulated genes. Similar stress conditions were often related to the same TE superfamily. Additionally, we detected both novel and known motifs in the sequences of those TEs pointing to regulatory cooption of these TEs upon stress. Next, we constructed the regulatory network of TFs that act through binding these TEs to their target genes upon stress and discovered TE-mediated regulons targeted by TFs such as BRB/BPC, HD, HSF, GATA, NAC, DREB/CBF and MYB factors in Arabidopsis and AP2/ERF/B3, NAC, NF-Y, MYB, CXC and HD factors in tomato. CONCLUSION: Overall, we map TE-mediated plant stress regulatory networks using numerous stress expression profile studies for two contrasting plant species to study the regulatory role TEs play in the response to stress. As TE-mediated gene regulation allows plants to adapt more rapidly to new environmental conditions, this study contributes to the future development of climate-resilient plantshttp://www.biomedcentral.com/bmcgenomicsBiochemistryGeneticsMicrobiology and Plant Patholog

Gouden kansen? Vastgoedstrategieën van bouwondernemers in de stadsuitleg van Amsterdam in de Gouden Eeuw

During the Dutch Golden Age, Amsterdam grew from a modest little town on the river Amstel into a powerful trading metropolis. Thanks to several very large-scale expansion schemes (in particular the third and fourth expansions), it became one of the biggest cities in Europe. This article does not focus on the design or implementation of the urban expansions. Instead, it concentrates on a subsequent phase in the development: the moment when the large public project broke up into thousands of private projects, which occurred when the government sold off building plots. The key questions posed in this article are whether the large scale of these expansions stimulated entrepreneurship in the building sector, and how that affected the urban landscape. Was there any increase in scale in the building sector, how did the sector deal with the opportunities offered by urban expansion and what strategies did it employ?It is the first time that such a very large quantitative study has been carried out for an early modern city. Amsterdam possesses exceptional series of sources that we were able to combine for this purpose. During the urban expansions, thousands of plots of land were sold at a succession of auctions, which resulted in maps and auction ledgers. These provide information about the plots and their buyers and allow us to calculate the proportion of building sector craftsmen investors and to work out which market segments they focused on (based on the location, size and price of the plots). Because we are primarily interested in the impact of major building booms, we concentrate on the periods 1614–1617. (when the land in the third expansion was sold and built on) and 1660–1699 (ditto for the fourth expansion).It transpires that building sector craftsmen were heavily over-represented in the real estate market compared with their colleagues from other production sectors. Nevertheless, only five to ten per cent of building sector cra'smen invested in land, which they usually bought in a dispersed fashion. In this way they gained access to the market, where they invested mainly in land intended for the social middle classes. (This was in contrast to the large-scale investors, who tended to concentrate on the market for workers’ housing.) In a few instances they built a house for themselves with a workshop from where they could offer their services to clients in the neighbourhood. In other cases, in particular among bricklayers, it seems that in buying land they were trying to gain direct access to the new-build market. This group sold their land fairly quickly, and in the case of a few master bricklayers we were able to ascertain that they immediately started building for the new owner. Quite a number of building cra'smen who started building on their own initiative, sold the building under construction at an early stage to the future owner. This strategy indicates that they had insufficient capital to pre-finance the entire construction and to market a finished product. In contrast to Niels Prak’s findings with regard to nineteenth-century Amsterdam, master building cra'smen did not immediately, and certainly not in large numbers, seize the opportunities offered by the large-scale urban expansions in seventeenth-century Amsterdam, at least not by building for the market on land they owned. Further research will be needed to show to what extent they opted for other forms of enterprise, such as a combination of builders’ merchant and construction work, or coordination of the building process for subcontractors.During the third expansion fairly large parcels of land were released, many of which were a'erwards subdivided, sometimes in order to build rows of smaller, uniform dwellings. The fourth expansion, by contrast, supplied a diversified parcellation that was much better aligned with market demands: large mansions on Herengracht and Keizersgracht, shop-dwellings along the radial streets, and a more mixed milieu with middle-class and smaller dwellings and industrial premises in the areas closer to the urban periphery. The urban structure laid down in those seventeenthcentury urban expansions and the buildings constructed on the allocated land, continue to determine the Amsterdam cityscape up to the present day