No description available.

Bovine bone grafts (BBX) require protein removal as part of the manufacturing process to reduce antigenicity and, in consequence, to be safely used in humans. Deproteinisation may have direct effects on the characteristics of the bone material and on in vivo material performance. This research aimed to comprehensively study the physicochemical and mechanical properties of BBX processed at low deproteinisation processing temperatures. Cubes of bovine bone (8 mm3) were treated with temperatures between 100 °C and 220 °C at 30 °C intervals and with pressures ranging from 1.01 to 24.58 Bar. The samples were characterised topographically and mechanically using scanning electron microscopy (SEM), atomic force microscopy (AFM), and uniaxial bending tests. The organic content and the chemical composition were determined using thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR). X-ray diffraction (XRD) and FTIR were also used to quantitatively determine the specimen crystallinity. Increasing temperature/pressure was associated with decreasing protein levels and compressive strength and increasing surface irregularities and crystallinity. The findings suggest that low-temperature processed bone is likely to exhibit a rapid in vivo degradation rate. The deproteinisation temperature can be adjusted to tailor the graft properties for specific applications.

Granular superconductivity at high temperatures in graphite can emerge at certain two-dimensional (2D) stacking faults (SFs) between regions with twisted (around the c-axis) or untwisted crystalline regions with Bernal (ABA…) and/or rhombohedral (ABCABCA…) stacking order. One way to observe experimentally such 2D superconductivity is to measure the frozen magnetic flux produced by a permanent current loop that remains after removing an external magnetic field applied normal to the SFs. Magnetic force microscopy was used to localize and characterize such a permanent current path found in one natural graphite sample out of ∼50 measured graphite samples of different origins. The position of the current path drifts with time and roughly follows a logarithmic time dependence similar to the one for flux creep in type II superconductors. We demonstrate that a ≃10 nm deep scratch on the sample surface at the position of the current path causes a change in its location. A further scratch was enough to irreversibly destroy the remanent state of the sample at room temperature. Our studies clarify some of the reasons for the difficulties of finding a trapped flux in a remanent state at room temperature in graphite samples with SFs.

Das Heizelementschweißen von Bauteilen großer Wanddicke wurde bisher wissenschaftlich kaum untersucht. In der DVS-Richtlinie wurden die Parameter für große Wanddicken linear extrapoliert. Die Veröffentlichung beschäftigt sich mit der systematischen Analyse des Heizelementschweißens von Wanddicken bis 100 mm. Weiterhin werden Prozessstrategien diskutiert, die zur Verbesserung der Langzeitfestigkeit von heizelementgeschweißten Bauteilen großer Wanddicke beitragen sollen.

In this work, we demonstrate that cutting diamond crystals with a laser (532 nm wavelength, 0.5 mJ energy, 200 ns pulse duration at 15 kHz) produced a ≲20 nm thick surface layer with magnetic order at room temperature. We measured the magnetic moment of five natural and six CVD diamond crystals of different sizes, nitrogen contents and surface orientations with a SQUID magnetometer. A robust ferromagnetic response at 300 K was observed only for crystals that were cut with the laser along the (100) surface orientation. The magnetic signals were much weaker for the (110) and negligible for the (111) orientations. We attribute the magnetic order to the disordered graphite layer produced by the laser at the diamond surface. The ferromagnetic signal vanished after chemical etching or after moderate temperature annealing. The obtained results indicate that laser treatment of diamond may pave the way to create ferromagnetic spots at its surface.

This article belongs to the Proceedings of The 37th International Symposium on Dynamical Properties of Solids.

Combining various (multi-)ferroic materials into heterostructures is a promising route to enhance their inherent properties, such as the magnetoelectric coupling in BiFeO3 thin films. We have previously reported on the up-to-tenfold increase of the magnetoelectric voltage coefficient αME in BaTiO3-BiFeO3 multilayers relative to BiFeO3 single layers. Unraveling the origin and mechanism of this enhanced effect is a prerequisite to designing new materials for the application of magnetoelectric devices. By careful variations in the multilayer design we now present an evaluation of the influences of the BaTiO3-BiFeO3 thickness ratio, oxygen pressure during deposition, and double layer thickness. Our findings suggest an interface driven effect at the core of the magnetoelectric coupling effect in our multilayers superimposed on the inherent magnetoelectric coupling of BiFeO3 thin films, which leads to a giant αME coefficient of 480 Vcm−1 Oe−1 for a 16×(BaTiO3-BiFeO3) superlattice with a 4.8 nm double layer periodicity.

No description available.

A novel exoskeleton robotic system was developed to assist stair climbing. This active demonstrator consists of a motor with a cable system, various sensors, and a control system with a power supply. The objective of this preliminary study is a biomechanical evaluation of the novel system to determine its effectiveness in use. For this purpose, three test persons were biomechan- ically investigated, who performed stair ascents and descents with and without the exoskeleton. Kinematics, kinetics, and muscle activity of the knee extensors were measured. The measured data were biomechanically simulated in order to evaluate the characteristics of joint angles, moments, and reaction forces. The results show that the new exoskeleton assists both the ascent and the descent according to the measured surface electromyography (sEMG) signals, as the knee extensors are relieved by an average of 19.3%. In addition, differences in the interaction between the test persons and the system were found. This could be due to a slightly different operation of the assisting force or to the different influence of the system on the kinematics of the users.

Throughout the course a long life in which he served as a cleric, a Cluniac monk, and an archbishop, Hugh of Amiens (c. 1085-1164) wrote a number of works including poems, biblical exegesis, anti-heretical polemics, and one of the early collections of systematic theology. This dissertation aims to provide an intellectual biography of Hugh which grants a better understanding not only of his motivations and ideals, but also some of those of the wider clerical and monastic world of the twelfth century. It examines each of Hugh's theological and literary compositions with their manuscript distribution, chronology, and contemporary setting, giving an in-depth exegesis of the texts including their concerns, sources of material, and their meaning within the context of their day. So too does it compare him with contemporaries who were writing similar works, from the compilers of sentences to biblical versifiers. Many themes surface in this work. One of these is the influence that both the scholastic and the monastic worlds had on Hugh. His writings show that he, along with many of his contemporaries, was secure in drawing inspiration from the contemplative spirit of the cloister as well as the methodical and disputatious endeavours of the schools. Another key theme is the extensive influence of St. Augustine, not just upon Hugh's thought, but also upon the thought of most of Hugh's contemporaries. The role of Hugh's works in the origin of systematic theology also emerges, as does their relation to events in the larger religious, social, and political scene, such as the rise of popular heresies and new religious movements, the condemnation of Gilbert de la Porree (c. 1076-1154), and the schism under Pope Alexander III (c. 1100-81). It concludes that Hugh was not only an intriguing individual, but also a representative of many of the important and widespread trends of his day.