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Quantum Dot/TiO2 Nanocomposite-Based Photoelectrochemical Sensor for Enhanced H2O2 Detection Applied for Cell Monitoring and Visualization
No full textThis work exploits the possibility of using CdSe/ZnS quantum dot (QD)-electrodes to monitor the metabolism of living cells based on photoelectrochemical (PEC) measurements. To realize that, the PEC setup is improved with respect to an enhanced photocurrent signal, better stability, and an increased signal-to-noise ratio, but also for a better biocompatibility of the sensor surface on which cells have been grown. To achieve this, a QD-TiO2 heterojunction is introduced with the help of atomic layer deposition (ALD). The heterojunction reduces the charge carrier recombination inside the semiconductor nanoparticles and improves the drift behavior. The PEC performance is carefully analyzed by adjusting the TiO2 thickness and combining this strategy with multilayer immobilizations of QDs. The optimal thickness of this coating is ≈5 nm; here, photocurrent generation can be enhanced significantly (e.g., for a single QD layer electrode by more than one order of magnitude at 0 V vs Ag/AgCl). The resulting optimized electrode is used for hydrogen peroxide (H2O2) sensing with a good sensitivity down to µmolar concentrations, reusability, stability, response rate, and repeatability. Finally, the sensing system is applied to monitor the activity of cells directly grown on top of the electrode surface
Matching competency frameworks with job advertisements: a data-driven analysis of its practical application in the healthcare sector
No full textPurpose
Competency-based human resource management (CBHRM) is a key component of all organisations but needs to be regularly reviewed and evaluated to ensure the quality of healthcare professionals. One common taxonomy of competency domains for health professions is from Englander et al., where this paper aims to conduct a large-scale analysis based on topic modelling to investigate the extent to which the competency framework for the healthcare sector is applied in the German job market of health professions.
Design/methodology/approach
The quantitative NLP analysis of a dataset consisting of 3,362 online job advertisements of nurses and doctors was scraped from a German job portal. The data was pre-processed according to Miner et al. For the analysis, the authors applied unsupervised (e.g. HDP, LDA) and supervised (BERTopic) methods and content analysis. Based on the extracted topics a word list was created and these words were coded to existing dimensions of the competency framework of Englander et al. or new dimensions were created.
Findings
Comparing methodologies, HDP (unsupervised) and BERTopic (supervised) were the best performing while the BERTopic algorithm outperforms HDP. For the doctor dataset 46% of one main dimension was identified but with an overall coverage of 69%, for the care dataset is weaker with 30.8% but an overall coverage of 100%. Additionally, the taxonomy was enhanced with supplementary competencies of “personality/characteristics” and “leadership” as well as two facets of job description which are “place of work” and “job conditions”.
Originality/value
On the one hand selected dimensions of the taxonomy could be clearly identified but on the other hand, there is a documented gap between the taxonomy and the competencies advertised. One cause may lie in the NLP algorithms but applicants may also have the same difficulties when reading the OJAs. Thus, practitioners should carefully review OJAs regarding better separating explicit competencies they are searching for. For the scientific development of new competency frameworks, our data-driven approach exemplified an extension of a given taxonomy
Fewer Errors through Learning-Teaching Orientation in Knowledge Work
No full textWissens- bzw. Nicht-Routinearbeit wie die Entwicklung von Smartphone-Apps oder von Software zur Steuerung moderner Flugzeuge ist per se fehleranfällig. Konkrete Beispiele aus dem täglichen Leben zeigen, dass derartige Fehler unübersehbare Schäden für Leib und Leben bedeuten können und daher zu vermeiden sind. Gegenseitiges Erklären und gemeinsames Verstehen von Sachverhalten, Anregungen, Ideen, Konzepten sind fehlerrelevante Bausteine von Wissensarbeit in Teams. Je besser diese speziellen Formen von Lehren (Erklären) und Lernen (Verstehen) gelingen, desto größer erscheinen die Chancen zur Fehlervermeidung. Entsprechend wird vorgeschlagen, die Wissensarbeit aus Lern- und Lehrsicht zu betrachten und mit Instrumenten aus der Didaktik zu unterstützen. Diese Lern-Lehr-Orientierung und ihr möglicher Beitrag zur Fehlerreduzierung werden beschrieben, an einem konkreten Beispiel ausgeführt und zusammenfassend erörtert.Knowledge work or non-routine work such as the development of smartphone apps or software for controlling modern aircraft is per se prone to errors. Concrete examples from everyday life show that such errors can mean incalculable damage to life and limb and must therefore be avoided. Mutual explanation and mutual understanding of facts, suggestions, ideas, concepts are error-relevant building blocks of knowledge work in teams. The better these special forms of teaching (explaining) and learning (understanding) succeed, the greater the chances of avoiding errors appear. Accordingly, it is suggested to view knowledge work from a learning and teaching perspective and to support it with instruments from didactics. This learning-teaching orientation and its contribution to error reduction are described, explained by one concrete example, and discussed in summary
Update on MAC End-Station at ELI Beamlines Facility
No full textThe MAC end-station at the ELI Beamlines facility is a multipurpose user's station for atomic, molecular, and optical sciences and coherent diffractive imaging. The technical design of the station, the available instruments, and an overview of the whole beamline have been published in Eur. Phys. J. Spec. Top. 230, 4183 (2021). Here, we address ongoing upgrades of the MAC end-station that will provide users with advanced capabilities for beam manipulation and electron/ion detection. The upgrades include (i) the installation of a beam preparation chamber in front of the MAC chamber, (ii) a magnetic bottle electron spectrometer with high collection and detection efficiency and high energy resolution, and (iii) an event-driven TPX3CAM detector for velocity map imaging spectrometer, which provides both spatial and temporal information for each pixel. We present results from the first commissioning measurements with these instruments, confirming their performance for state-of-the-art experiments in atomic, molecular, and optical sciences
Qualitative and quantitative protease activity tests based on protein degradation in three-dimensional structures
No full textThe pattern of the activity of proteases is related to distinct physiological states of living organisms. Often activity changes of a certain protease can be assigned to a specific disease. Hence, they are useful biomarkers and a simple and fast determination method of their activity could be a valuable tool for the efficient monitoring of numerous diseases. Here, two different methods for the qualitative and quantitative determination of protease activity are demonstrated using the model system of proteinase K. The first test system is based on a protein-modified and colored 3D silica structure that changes color when exposed to the enzyme. This method has also been used for the detection of matrix metallo-protease 2 (MMP2) with gelatine as protease substrate on the plates. The second detection system uses the decrease in the voltammetric signal of a cytochrome c/DNA multilayer electrode after incubation with a protease to quantitatively determine its proteolytic activity. While activities down to 0.15 U/ml can be detected with the first method, the second one provides detection limits of about 0.03 U/ml (for proteinase K.) The functionality of both systems can be demonstrated and ways for further enhancement of sensitivity have been elucidated
Quantitative und Qualitative Untersuchung zur Akzeptanz und Gestaltung von physischer Mensch-Roboter-Kollaboration
No full textDieser Beitrag beschreibt zwei Studien zur Akzeptanz eines Messroboters zur Durchführung von dermatologischen In-Vivo-Messungen. Die erste Studie ist eine quantitative Online-Umfrage mit 745 Teilnehmern. Die Studie gliedert sich in drei Bereiche mit insgesamt 24 Fragen. Die Teilnehmer werden zu ihren Erfahrungen und Ängsten in Bezug auf Roboter befragt und insbesondere zu einem möglichen Einsatz eines Messroboters für dermatologische In-Vivo-Studien. Für die qualitative Studie werden insgesamt 17 Studienteilnehmer jeweils einzeln für ein zweistündiges Interview, welches in 4 Phasen gegliedert ist, eingeladen. In Phase 2 dieser Studie werden die ersten robotergestützten In-Vivo-Messungen an Hautarealen auf dem Unterarm der Teilnehmer durchgeführt. Bereits aus der quantitativen Umfrage geht hervor das die meisten (75 %) Teilnehmer der Idee von Robotern im Messbetrieb offen gegenüber stehen, 55,7% befürworten den Einsatz sogar. Während des quantitativen Interviews werden Ängste und Unsicherheiten vor und während der ersten Messung genannt und beobachtet. Alle Teilnehmer waren zur Wiederholungsmessung sehr viel sicherer im Umgang mit dem Roboter und können sich einen zukünftigen Einsatz vorstellen. Besondere Herausforderungen stellen sich hinsichtlich der Positionierung der Studienteilnehmer zum Roboter heraus. Die Sicherstellung einer ergonomischen Gestaltung der Roboterumgebung ist für physische Mensch-Roboter-Kollaboration entscheidend und wird zur Weiterentwicklung des Systems stärker berücksichtigt. Weiter wurde ein 3-Stufen-Zustimmschalter zur Absicherung der Roboterbewegungen verwendet, dieser fand allerdings wenig Anklang und wurde stark kritisiert. Für den zukünftigen Einsatz wird eine alternative Überwachung des direkten Arbeitsbereiches erarbeitet
Ein neuer Sensoransatz für die Feinpositionierung eines O-Bus Stromabnehmers
No full textUrbane Mobilität insbesondere der innerstädtischen Personentransport wird auch zukünftig ein besonderes Augenmerk unter dem Eindruck nachhaltiger Nutzung von Energiesystemen haben. Hierbei besitzt der öffentliche Personennahverkehr(ÖPNV) ein großes Potential zur großskaligen Minderung des Kohlendioxid ausstoßes. Ein sehr wichtiges Konzept hierbei ist der Oberleitungsbus der ganz analog zu einer Straßenbahn über eine Oberleitung fahrbahnbegleitend mit Strom versorgt wird. Da der Bus naturgemäß nicht schienengebunden fährt und somit ein gewisses Maß an Positionsungenauigkeit besitzt, ist das Eindrahten an die Oberleitung allerdings erschwert. In dieser Arbeit präsentieren wir einen Regelungsansatz basierend auf einer neuartigen Sensorkonfiguration, der das automatische Eindrahten eines Stromabnehmers auf einem Bus ermöglichen kann
Toxicity of Water-Soluble D-g-PNIPAM Polymers in a Complex with Chemotherapy Drugs and Mechanism of Their Action In Vitro
No full textThe application of a biocompatible polymer nanocarrier can provide target delivery to tumor tissues, improved pharmacokinetics, controlled drug release, etc. Therefore, the proposed strategy was to use the water-soluble star-like copolymers with a Dextran core and Poly(N-isopropylacrylamide) grafts (D-g-PNIPAM) for conjugation with the widely used chemotherapy drugs in oncology–Cisplatin (Cis-Pt) and Doxorubicin (Dox). The molecular characteristics of the copolymer were received using size-exclusion chromatography. The physicochemical characterization of the D-g-PNIPAM-Cis-Pt (or Dox) nanosystem was conducted using dynamic light scattering and FTIR spectroscopy. Using traditional biochemical methods, a comparative analysis of the enhancement of the cytotoxic effect of free Cis-Pt and Dox in combination with D-g-PNIPAM copolymers was performed in cancer cells of the Lewis lung carcinoma line, which are both sensitive and resistant to Dox; in addition, the mechanism of their action in vitro was evaluated
Adhesive-free bonding for hetero-integration of InP based coupons micro-transfer printed on SiO2 into Complementary Metal-Oxide-Semiconductor backend for Si photonics application on 8” wafer platform
No full textMicro-Transfer printing (µTP) is a promising technique for hetero-integration of III-V materials into Si-based photonic platforms. To enhance the print yield by increasing the adhesion between the III-V material and Si or SiO2 surface, an adhesion promoter like Benzocyclobutene is typically used as interlayer. In this work, we demonstrate µTP of InP based coupons on SiO2 interlayer without any adhesive interlayer and investigate the mechanism of adhesive free bonding. Source coupons are InP-based coupon stacks on a sacrificial layer that is removed by a chemical wet etch with FeCl3. For the target we fabricated amorphous-Si waveguides on 8” wafer encapsulated by a High Density Plasma SiO2 which was planarized by a chemical mechanical polishing procedure. We used O2 plasma to activate both source and target to increase adhesion between coupon and substrate. To get a better understanding of the bonding mechanism we applied several surface characterization methods. Root mean square roughness of InP and SiO2 was measured by atomic force microscopy before and after plasma activation. The step height of the micro-transfer printed source coupon on the target wafer is estimated by optical step profiler. We used Raman peak position mappings of InP to analyze possible strain and contact angle measurements on SiO2, before and after plasma activation to observe a change in the hydrophilicity of the surface. X-ray Photoelectron Spectroscopy analysis was used to characterize the surface energy states of P2p, In3d, O1s for InP source and Si2p, O1s for SiO2 target. Our results demonstrate direct bonding of InP coupons by means of µTP without the need of a strain-compensation layer. In this way, a promising route towards Complementary Metal-Oxide-Semiconductor compatible use of µTP for the hetero-integration of InP is provided
Methodik zur Analyse des Lagerringwanderns mithilfe von Ansatzvektoren
No full textDer Schadensmechanismus Lagerringwandern stellt Maschinenbaufirmen vor große Herausforderungen, da gängige Berechnungswerkzeuge wichtige Systemeinflüsse aufgrund hoher Berechnungszeiten nicht einbeziehen können. Der Schadensmechanismus ist damit zumeist ein unvermeidliches Problem und kann die Betriebszeit von Antrieben erheblich limitieren. Basierend auf dieser Problemstellung wird im Beitrag ein Ansatzvektorverfahren untersucht, welches mithilfe einer nichtlinearen Modellordnungsreduktion die Berechnungszeiten bisheriger Methoden reduzieren und somit den Weg zur Analyse des Lagerringwanderns innerhalb von Systemsimulationen ebnen kann. Der Fokus liegt dabei auf der Vorstellung des Verfahrens sowie einer grundlegenden Studie hinsichtlich Ergebnisqualität und Performanz.Bearing creep poses significant challenges to mechanical engineers, as common calculation tools often cannot account for important system influences due to high computation times. Consequently, this damage mechanism is usually an unavoidable issue and can significantly limit the operational life of drive systems. Addressing this problem, this paper investigates a trial vector method, which utilizes nonlinear model order reduction to decrease the computation effort of existing methods, thus paving the way for the analysis of bearing creep within system simulations. The focus lies on introducing the method and conducting a fundamental study regarding result quality and performance