X-ray computed tomography for additive manufacturing: a review

In this review, the use of x-ray computed tomography (XCT) is examined, identifying the requirement for volumetric dimensional measurements in industrial verification of additively manufactured (AM) parts. The XCT technology and AM processes are summarised, and their historical use is documented. The use of XCT and AM as tools for medical reverse engineering is discussed, and the transition of XCT from a tool used solely for imaging to a vital metrological instrument is documented. The current states of the combined technologies are then examined in detail, separated into porosity measurements and general dimensional measurements. In the conclusions of this review, the limitation of resolution on improvement of porosity measurements and the lack of research regarding the measurement of surface texture are identified as the primary barriers to ongoing adoption of XCT in AM. The limitations of both AM and XCT regarding slow speeds and high costs, when compared to other manufacturing and measurement techniques, are also noted as general barriers to continued adoption of XCT and AM

Minimum Wages as a Barrier to Entry – Evidence from Germany

This study analyses employers' support for the introduction of industry-specific minimum wages as a cost-raising strategy in order to deter market entry. Using a unique data set consisting of 800 firms in the German service sector, we find some evidence that high-productivity employers support minimum wages. We further show that minimum wage support is higher in industries and regions with low barriers to entry. This is particularly the case in East Germany, where the perceived threat of low-wage competition from Central and Eastern European countries is relatively high. In addition, firms paying collectively agreed wages are more strongly in favour of minimum wages if union coverage is low and the mark-up of union wage rates is high.Diese Studie analysiert, in welchem Maße Arbeitgeber die Einführung von sektoralen Mindestlöhnen unterstützen, um durch diese Kostenerhöhung den Marktzugang zu erschweren. Die Datengrundlage bildet ein einzigartiger Datensatz, der 800 Firmen im Dienstleistungsbereich in Deutschland abdeckt. Wir finden Hinweise darauf, dass Arbeitgeber mit hoher Produktivität Mindestlöhne unterstützen. Außerdem zeigen wir, dass die Zustimmung zu einer Mindestlohneinführung in Wirtschaftszweigen und Regionen höher ist, wenn die dortigen Markteintrittsbarrieren geringer sind. Dies ist vor allem in Ostdeutschland der Fall, wo der Konkurrenzdruck durch Niedriglohnkonkurrenz aus Mittel- und Osteurope als besonders stark wahrgenommen wird. Des Weiteren befürworten Arbeitgeber, die tariflich vereinbarte Löhne zahlen, Mindestlöhne vor allem dann, wenn der gewerkschaftliche Abdeckungsgrad und der tarifliche Lohnaufschlag besonders hoch sind

Accelerating functional gene discovery in osteoarthritis

Osteoarthritis causes debilitating pain and disability, resulting in a considerable socioeconomic burden, yet no drugs are available that prevent disease onset or progression. Here, we develop, validate and use rapid-throughput imaging techniques to identify abnormal joint phenotypes in randomly selected mutant mice generated by the International Knockout Mouse Consortium. We identify 14 genes with functional involvement in osteoarthritis pathogenesis, including the homeobox gene Pitx1, and functionally characterize 6 candidate human osteoarthritis genes in mouse models. We demonstrate sensitivity of the methods by identifying age-related degenerative joint damage in wild-type mice. Finally, we phenotype previously generated mutant mice with an osteoarthritis-associated polymorphism in the Dio2 gene by CRISPR/Cas9 genome editing and demonstrate a protective role in disease onset with public health implications. We hope this expanding resource of mutant mice will accelerate functional gene discovery in osteoarthritis and offer drug discovery opportunities for this common, incapacitating chronic disease

Graviceptive misperception of the postural vertical after right hemisphere damage

We have systematically studied the subjective postural vertical (SPV) and the location of the centre of gravity (COG) in right brain damaged patients, classified according to the severity of their hemispatial neglect. The results indicate that the patients lean towards the side of space where they feel aligned with their ipsilesionally displaced SPV, resulting in a ipsilesional deviation of the COG. This displacement can be reduced by the effect of contralesionally applied transcutaneous electrical nerve stimulation (TENS). However, in the severe neglect patients, an increasing mismatch arised between the perceived body orientation and the direction of the gravitational force. The results indicate that this conflict is compensated by a contraversive shift of the COG towards the contraversive side in order to re-align the SPV with the gravitational vertical

Attention networks in Parkinson’s disease: Freezing of gait related to impaired conflict resolution?

status: publishe

Baking Gradients Cause Heterogeneity in Starch and Proteins in Pound Cake

peer reviewedWe investigated the impact of temperature and moisture gradients on starch gelatinization and egg denaturation, and on protein extractabilities during cake baking. Differences in crumb structure in the center, top, and bottom zones of cake as measured with X-ray microfocus-computed tomography were successfully related to the moment at which starch gelatinized and protein aggregated during baking, which stiffened the cell walls. The temperature in the top and bottom zones of cake increased faster than in the center of the cake due to facilitated heat transfer. This resulted in lower water availability in top and bottom zones, leading to incomplete gelatinization of starch after baking in these zones. In the top zone, extended starch gelatinization and protein polymerization led to later cell wall formation, resulting in a broader cell size distribution. The bottom zone of cake reached the highest temperatures during baking with more substantial starch gelatinization and egg denaturation within the first 25 min of baking. During the final 20 min of baking, little if any change in gelatinization enthalpy and protein extractability was found due to the very low water availability in this region. The bottom zone of the crumb showed a broader cell wall size distribution, which was associated with more collapse. All in all, the results illustrate that cake crumb is not a homogeneous material