Vacuum lamination of a stretchable sensor system in polypropylene

The explosive growth of the so-called Internet-of-Things, where more and more everyday objects are becoming `smart' and connected, demands for reliable integration technologies for electronics in all kinds of materials. If we want these electronics to be as least intrusive as possible, they preferably conform to the shape of the contemplated object. In this article we want to present a technique that allows the integration of a smart sensor system in a thermoplastic material (polypropylene, PP) by vacuum lamination. This laminated stack can then be thermoformed from a flat sheet into the desired 3D shape. The sensor system in question is a sensor bus incorporating three inertial movement sensors. Each sensor is placed on a separate small, thin (200μm) FR4 PCB together with some necessary peripheral components. These smart sensor nodes are then placed on a flexible, stretchable circuit, which is then laminated between two 2mm-thick PP sheets. These sheets can subsequently be heated and thermoformed. In this particular case, the PP was used to create a smart ankle-foot orthosis (AFO). Although long-term reliability needs to be improved, we can show that the discussed technology allows for a successful lamination and thermoforming. This paper will elaborate on the sensor system, stretchable bus system and lamination technique, together with the encountered problems and implemented mitigations. While the current application is the aforementioned AFO, the sensor system can easily be expanded to other types of sensors and the thermoforming process allows for a wide range of possible applications

A validated computational framework to evaluate the stiffness of 3D printed ankle foot orthoses

The purpose of this study was to create and validate a standardized framework for the evaluation of the ankle stiffness of two designs of 3D printed ankle foot orthoses (AFOs). The creation of four finite element (FE) models allowed patient-specific quantification of the stiffness and stress distribution over their specific range of motion during the second rocker of the gait. Validation was performed by comparing the model outputs with the results obtained from a dedicated experimental setup, which showed an overall good agreement with a maximum relative error of 10.38% in plantarflexion and 10.66% in dorsiflexion. The combination of advanced computer modelling algorithms and 3D printing techniques clearly shows potential to further improve the manufacturing process of AFOs

Development and clinical evaluation of laser-sintered ankle foot orthoses

Ankle foot orthoses (AFOs) are traditionally manufactured using vacuum thermoforming as shaping technology. Additive manufacturing has the potential to disruptively change the way these orthopaedic devices are produced. In this study, AFOs are developed which are virtually designed and produced with laser sintering as shaping technology. The mechanical and clinical performances of these laser-sintered AFOs are compared with traditionally manufactured AFO by asking seven patients (both children and adults) to walk with each type of AFO

Genetic associations at 53 loci highlight cell types and biological pathways relevant for kidney function.

Reduced glomerular filtration rate defines chronic kidney disease and is associated with cardiovascular and all-cause mortality. We conducted a meta-analysis of genome-wide association studies for estimated glomerular filtration rate (eGFR), combining data across 133,413 individuals with replication in up to 42,166 individuals. We identify 24 new and confirm 29 previously identified loci. Of these 53 loci, 19 associate with eGFR among individuals with diabetes. Using bioinformatics, we show that identified genes at eGFR loci are enriched for expression in kidney tissues and in pathways relevant for kidney development and transmembrane transporter activity, kidney structure, and regulation of glucose metabolism. Chromatin state mapping and DNase I hypersensitivity analyses across adult tissues demonstrate preferential mapping of associated variants to regulatory regions in kidney but not extra-renal tissues. These findings suggest that genetic determinants of eGFR are mediated largely through direct effects within the kidney and highlight important cell types and biological pathways

Catalytic Trimerization of Ethene with Highly Active Cyclopentadienyl-Arene Titanium Catalysts

The mono(cyclopentadienyl-arene)titanium complexes [η5-C5H3R-(bridge)-Ar]TiCl3, activated by methylalumoxane (MAO) cocatalyst, form a family of highly active catalysts for the trimerization of ethene, giving 1-hexene as the main product. Concomitant cotrimerization of ethene and 1-hexene, to give mainly 5-methylnon-1-ene, is also observed. The selectivity for trimerization depends on the presence of a pendant arene group on the cyclopentadienyl ligand and the nature of the bridge between these two ligand moieties. In the absence of a pendant arene, polyethene is the main product. The highest activity and selectivity for trimerization was observed for catalysts with a disubstituted C1 bridge between the cyclopentadienyl and arene ligand moieties. A SiMe3 substituent on the cyclopentadienyl ligand improves catalyst activity and selectivity, whereas methyl substitution of the arene decreases activity. Nevertheless, combining cyclopentadienyl SiMe3 substitution with arene Me substitution gives rise to a catalyst with the highest activity and selectivity, evidence of the strongly nonlinear additivity of ligand substituent effects in this system. The cyclopentadienyl-arene ligand is likely to exhibit hemilabile behavior during catalysis, stabilizing intermediates by η6 coordination and dissociating or slipping to make room for the incoming substrate. The presence of two pendant arene groups on the cyclopentadienyl ligand diminishes the activity of the catalyst but greatly enhances its stability.

Lumen narrowing after percutaneous transluminal coronary balloon angioplasty follows a near gaussian distribution: a quantitative angiographic study in 1,445 successfully dilated lesions

To determine whether significant angiographic narrowing and restenosis after successful coronary balloon angioplasty is a specific disease entity occurring in a subset of dilated lesions or whether it is the tail end of a gaussian distributed phenomenon, 1,445 successfully dilated lesions were studied before and after coronary angioplasty and at 6-month follow-up study. The original cohort consisted of 1,353 patients of whom 1,232 underwent repeat angiography with quantitative analysis (follow-up rate 91.2%). Quantitative angiography was carried out off-line in a central core laboratory with an automated edge detection technique. Analyses were performed by analysts not involved with patient care. Distributions of minimal lumen diameter before angioplasty (1.03 +/- 0.37 mm), after angioplasty (1.78 +/- 0.36 mm) and at 6-month follow-up study (1.50 +/- 0.57 mm) as well as the percent diameter stenosis at 6-month follow-up study (44 +/- 19%) were assessed. The change in minimal lumen diameter from the post-angioplasty angiogram to the follow-up angiogram was also determined (-0.28 +/- 0.52 mm). Seventy lesions progressed toward total occlusion at follow-up. All observed distributions approximately followed a normal or gaussian distribution. Therefore, restenosis can be viewed as the tail end of an approximately gaussian distributed phenomenon, with some lesions crossing a more or less arbitrary cutoff point, rather than as a separate disease entity occurring in some lesions but not in others

Long-acting coronary vasodilatory action of the molsidomine metabolite Sin I: a quantitative angiographic study

The vasodilatory action of molsidomine was studied by intracoronary injection of its active metabolite, Sin 1. In 10 patients repeat coronary angiography in multiple projections was performed before and 2 minutes after administration of 1 mg of Sin 1, and before and after a second injection 60 minutes later. Contours of obstructed and non-obstructed segments of the left coronary artery were quantitatively analysed with a computer-based angiography analysis system. Immediately after its administration, Sin 1 increased the mean diameters of 44 normal coronary segments by 12% (P less than 0.001). Significant vasodilation (8%) was still observed after 60 minutes. At that time, repeated administration of Sin 1 increased the vasodilation by an additional 14% with respect to the control situation. An increase in obstruction diameter was observed in 6 out of 8 obstructed segments. Mean increase in the minimal obstructio