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Background:
Additional stabilization of the “comma sign” in anterosuperior rotator cuff repair has been proposed to provide biomechanical benefits regarding stability of the repair.
Purpose:
This in vitro investigation aimed to investigate the influence of a comma sign–directed reconstruction technique for anterosuperior rotator cuff tears on the primary stability of the subscapularis tendon repair.
Study Design:
Controlled laboratory study.
Methods:
A total of 18 fresh-frozen cadaveric shoulders were used in this study. Anterosuperior rotator cuff tears (complete full-thickness tear of the supraspinatus and subscapularis tendons) were created, and supraspinatus repair was performed with a standard suture bridge technique. The subscapularis was repaired with either a (1) single-row or (2) comma sign technique. A high-resolution 3D camera system was used to analyze 3-mm and 5-mm gap formation at the subscapularis tendon-bone interface upon incremental cyclic loading. Moreover, the ultimate failure load of the repair was recorded. A Mann-Whitney test was used to assess significant differences between the 2 groups.
Results:
The comma sign repair withstood significantly more loading cycles than the single-row repair until 3-mm and 5-mm gap formation occurred (P≤ .047). The ultimate failure load did not reveal any significant differences when the 2 techniques were compared (P = .596).
Conclusion:
The results of this study show that additional stabilization of the comma sign enhanced the primary stability of subscapularis tendon repair in anterosuperior rotator cuff tears. Although this stabilization did not seem to influence the ultimate failure load, it effectively decreased the micromotion at the tendon-bone interface during cyclic loading.
Clinical Relevance:
The proposed technique for stabilization of the comma sign has shown superior biomechanical properties in comparison with a single-row repair and might thus improve tendon healing. Further clinical research will be necessary to determine its influence on the functional outcome.
Was ist „Männlichkeit“ und was verstehen junge Erwachsene unter diesem Begriff? Das Ziel des Projektes war 18 bis 30 jährige Jungen und Männer des biologisch männlichen Geschlechts zu befragen, was ihre Definition von Männlichkeit sei. Diese Arbeit hatte die Intention den Befragten einen sicheren Raum zu geben, damit sie ihre ehrlichen Antworten äußern und ihre wahren Gesichter zeigen können. Die dabei entstandenen Fotografien sollen die Persönlichkeiten und die seelische Verfassung der abgebildeten Personen widerspiegeln. Es handelt sich um eine soziologische Bestandsaufnahme der „Männlichkeiten“ der heutigen Jugend und der heranwachsenden Erwachsenen im 21. Jahrhundert.
The planned coal phase-out in Germany by 2038 will lead to the dismantling of power plants with a total capacity of approx. 30 GW. A possible further use of these assets is the conversion of the power plants to thermal storage power plants; the use of these power plants on the day-ahead market is considerably limited by their technical parameters. In this paper, the influence of the technical boundary conditions on the operating times of these storage facilities is presented. For this purpose, the storage power plants were described as an MILP problem and two price curves, one from 2015 with a relatively low renewable penetration (33 %) and one from 2020 with a high renewable energy penetration (51 %) are compared. The operating times were examined as a function of the technical parameters and the critical influencing factors were investigated. The thermal storage power plant operation duration and the energy shifted with the price curve of 2020
increases by more than 25 % compared to 2015.
This paper introduces a new maritime search and rescue system based on S-band illumination harmonic radar (HR). Passive and active tags have been developed and tested while attached to life jackets and a small boat. In this demonstration test carried out on the Baltic Sea, the system was able to detect and range the active tags up to a distance of 5800 m using an illumination signal transmit-power of 100 W. Special attention is given to the development, performance, and conceptual differences between passive and active tags used in the system. Guidelines for achieving a high HR dynamic range, including a system components description, are given and a comparison with other HR systems is performed. System integration with a commercial maritime X-band navigation radar is shown to demonstrate a solution for rapid search and rescue response and quick localization.
Test-retest reliability of the internal shoulder rotator muscles' stretch reflex in healthy men
(2021)
Until now the reproducibility of the short latency stretch reflex of the internal rotator muscles of the glenohumeral joint has not been identified. Twenty-three healthy male participants performed three sets of external shoulder rotation stretches with various pre-activation levels on two different dates of measurement to assess test-retest reliability. All stretches were applied with a dynamometer acceleration of 104°/s2 and a velocity of 150°/s. Electromyographical response was measured via surface EMG. Reflex latencies showed a pre-activation effect (ƞ2 = 0,355). ICC ranged from 0,735 to 0,909 indicating an overall “good” relative reliability. SRD 95% lay between ±7,0 to ±12,3 ms.. The reflex gain showed overall poor test-retest reproducibility. The chosen methodological approach presented a suitable test protocol for shoulder muscles stretch reflex latency evaluation. A proof-of-concept study to validate the presented methodical approach in shoulder involvement including subjects with clinically relevant conditions is recommended.
Eine Kampagne, die darauf ausgerichtet ist, die Bevölkerung auf sozialer Ebene aufzurufen, Impf-Skeptiker aufzuklären und von Impfungen zu überzeugen. Anhand von offiziellen Statistiken, die optisch ansprechend aufbereitet wurden, werden die Menschen über Krankheiten und dazu gehörige Risiken informiert. Des Weiteren wird der Impferfolg grafisch dokumentiert und leicht verständlich präsentiert, ohne Fakten auszulassen.
Durch eine Serie Plakate verschiedener Formate werden die Betrachter animiert, die Homepage impfen.info aufzusuchen und das reichhaltige Informationsangebot zu nutzen.
Mithilfe einer amüsanten Postkartenreihe wird die Verbreitung von Krankheitserregern simuliert und postalisch in die Haushalte der Impfgegner- und Skeptiker gebracht, um zu verdeutlichen, wie rasant Viren sich verbreiten und wie wichtig es ist, sich und seine Lieben zu schützen.
Die Kunst des Theaters ist alt. Gegenwärtig zählt sie allerdings immer noch zu den wichtigsten Trägern des künstlerischen Kulturguts. Doch die Welt in der wir leben hat sich in den letzten Jahren deutlich verändert. Sie ist komplexer geworden. Die Anzahl der losen Informationen, die in unsere Wahrnehmungsbereiche hineinragen, hat sich explosionsartig erhöht. Ein großer Anteil dieser Veränderung ist auf die Digitalisierung verschiedener Lebensbereiche zurückzuführen. Die Werkzeuge, welche im Zuge der Digitalisierung kreiert wurden, werden von den meisten heute selbstverständlich genutzt. Doch was bedeutet diese neue Entwicklung für das Theater und wie sollte es auf diese Veränderungen reagieren? Als gestalterische Antwort entstand ein neues Erscheinungsbild, welches crossmedial sowohl die analogen Säulen des Theaters, als auch die neuen digitalen Formen des Alltags auffangen und kommunizieren kann.
This paper presents a new SIMO radar system based on a harmonic radar (HR) stepped frequency continuous wave (SFCW) architecture. Simple tags that can be electronically individually activated and deactivated via a DC control voltage were developed and combined to form an MO array field. This HR operates in the entire 2.45 GHz ISM band for transmitting the illumination signal and receives at twice the stimulus frequency and bandwidth centered around 4.9 GHz. This paper presents the development, the basic theory of a HR system for the characterization of objects placed into the propagation path in-between the radar and the reflectors (similar to a free-space measurement with a network analyzer) as well as first measurements performed by the system. Further detailed measurement series will be made available later on to other researchers to develop AI and machine learning based signal processing routines or synthetic aperture radar algorithms for imaging, object recognition, and feature extraction. For this purpose, the necessary information is published in this paper. It is explained in detail why this SIMO-HR can be an attractive solution augmenting or replacing existing systems for radar measurements in production technology for material under test measurements and as a simplified MIMO system. The novel HR transfer function, which is a basis for researchers and developers for material characterization or imaging algorithms, is introduced and metrologically verified in a well traceable coaxial setup.
This article introduces a new maritime search and rescue system based on S-band illumination harmonic radar (HR). Passive and active tags have been developed and tested attached to life jackets and a rescue boat. This system was able to detect and range the active tags up to a range of 5800 m in tests on the Baltic Sea with an antenna input power of only 100 W. All electronic GHz components of the system, excluding the S-band power amplifier, were custom developed for this purpose. Special attention is given to the performance and conceptual differences between passive and active tags used in the system and integration with a maritime X-band navigation radar is demonstrated.
Zwei sind eine Gemeinschaft: Illustrative Neuinterpretation des Romans "Eine Insel" von T. Pratchett
(2021)
Das Projekt „Zwei sind eine Gemeinschaft“ befasst sich mit der Entwicklung einer gebundenen Fassung der Graphic Novel als Adaption des Kinderromans „Eine Insel“ von Terry Pratchett. Diese soll den Betrachtenden ermöglichen, mittels ansprechenden Illustrationen tiefer in die fantasievolle Welt der Geschichte einzutauchen, dem Alltag zu entfliehen und so die Begeisterung zum Medium Buch wieder aufleben zu lassen. Durch die Verbindung von Techniken des Grafikdesigns und der klassischen Illustration verbindet der Stil sowohl die moderne, ausdrucksstarke und sehr grafische Bildsprache mit der Eigenschaft, kreativen Interpretationsspielraum zu lassen und tiefe Emotionen zu erzeugen. Die besondere Innovation des Projekts zeigt sich durch das Konzept des illustrativen Baukastensystems, welches ermöglicht, die einzelnen Illustrationen effizient und intuitiv zu gestalten.
During the Covid-19 pandemic, vocational colleges, universities of applied science and technical universities often had to cancel laboratory sessions requiring students’ attendance. These above of all are of decisive importance in order to give learners an understanding of theory through practical work.This paper is a contribution to the implementation of distance learning for laboratory work applicable for several upper secondary educational facilities. Its aim is to provide a paradigm for hybrid teaching to analyze and control a non-linear system depicted by a tank model. For this reason, we redesign a full series of laboratory sessions on the basis of various challenges. Thus, it is suitable to serve different reference levels of the European Qualifications Framework (EQF).We present problem-based learning through online platforms to compensate the lack of a laboratory learning environment. With a task deduced from their future profession, we give students the opportunity to develop own solutions in self-defined time intervals. A requirements specification provides the framework conditions in terms of time and content for students having to deal with the challenges of the project in a self-organized manner with regard to inhomogeneous previous knowledge. If the concept of Complete Action is introduced in classes before, they will automatically apply it while executing the project.The goal is to combine students’ scientific understanding with a procedural knowledge. We suggest a series of remote laboratory sessions that combine a problem formulation from the subject area of Measurement, Control and Automation Technology with a project assignment that is common in industry by providing extracts from a requirements specification.
Concentrating Solar Power
(2021)
The focus of this chapter is the production of power and the use of the heat produced from concentrated solar thermal power (CSP) systems.
The chapter starts with the general theoretical principles of concentrating systems including the description of the concentration ratio, the energy and mass balance. The power conversion systems is the main part where solar-only operation and the increase in operational hours.
Solar-only operation include the use of steam turbines, gas turbines, organic Rankine cycles and solar dishes. The operational hours can be increased with hybridization and with storage.
Another important topic is the cogeneration where solar cooling, desalination and of heat usage is described.
Many examples of commercial CSP power plants as well as research facilities from the past as well as current installed and in operation are described in detail.
The chapter closes with economic and environmental aspects and with the future potential of the development of CSP around the world.
Die »tape foundry« ist eine interdisziplinäre Distributionsplattform für studentische Schriften, die Studierende auf dem großen Type-Design Markt neu platziert und einen Raum zur Entfaltung gibt. Besonders durch Instagram ist die heutige Type-Designszene größer denn je und viele Entwürfe gehen in der Maße unter. Um diesem Phänomen entgegenzuwirken wurde die »tape foundry« ins Leben gerufen. Sie versucht mit der Kombination aus Fotografie, Type Design und der Funktion als Kassettenlabel neue interdisziplinäre Wege zu gehen, um sich von der klassischen Ästhetik abzusetzen. Die Webseite stellt sich bewusst gegen gängige UX/UI Standards und setzt auf neue Nutzungsprinzipien kombiniert mit einer lauten kontrastreichen Bildwelt.
Kawasaki Heavy Industries, LTD. (KHI) has research and development projects for a future hydrogen society. These projects comprise the complete hydrogen cycle, including the production of hydrogen gas, the refinement and liquefaction for transportation and storage, and finally the utilization in a gas turbine for electricity and heat supply. Within the development of the hydrogen gas turbine, the key technology is stable and low NOx hydrogen combustion, namely the Dry Low NOx (DLN) hydrogen combustion.
KHI, Aachen University of Applied Science, and B&B-AGEMA have investigated the possibility of low NOx micro-mix hydrogen combustion and its application to an industrial gas turbine combustor. From 2014 to 2018, KHI developed a DLN hydrogen combustor for a 2MW class industrial gas turbine with the micro-mix technology. Thereby, the ignition performance, the flame stability for equivalent rotational speed, and higher load conditions were investigated. NOx emission values were kept about half of the Air Pollution Control Law in Japan: 84ppm (O2-15%). Hereby, the elementary combustor development was completed.
From May 2020, KHI started the engine demonstration operation by using an M1A-17 gas turbine with a co-generation system located in the hydrogen-fueled power generation plant in Kobe City, Japan. During the first engine demonstration tests, adjustments of engine starting and load control with fuel staging were investigated. On 21st May, the electrical power output reached 1,635 kW, which corresponds to 100% load (ambient temperature 20 °C), and thereby NOx emissions of 65 ppm (O2-15, 60 RH%) were verified. Here, for the first time, a DLN hydrogen-fueled gas turbine successfully generated power and heat.