Evaluating a peer-led wellbeing programme for doctors-in-training during the COVID-19 pandemic in Victoria, Australia, using the most significant change technique

This article discusses the use of the Most Significant Change (MSC) technique in a mixed-methods evaluation of a pilot wellbeing programme for obstetrics and gynaecology doctors-in-training introduced at a large public hospital during Melbourne, Australia’s second coronavirus (COVID-19) lockdown, which occurred from 7 July to 26 October 2020. The evaluation was conducted remotely using videoconferencing technology, to conform with pandemic restrictions. MSC complemented the program’s participatory principles and was chosen because it seeks to learn about participants’ perceptions of programme impacts by evaluating their stories of significant change. Stakeholders select one story exemplifying the most significant change resulting from the evaluated program. Inductive thematic analysis of all stories is combined with reasons for making the selection, to inform learnings (Dart & Davies, 2003; Tonkin et al., 2021). Nine stories of change were included in the selection. The most significant change was a more supportive workplace culture brought about by enabling basic needs to be met and breaking down hierarchical barriers. This was linked to five interconnected themes – connection, caring, communication, confidence and cooperation. The evaluation learnings are explored and reflections on remotely conducting MSC evaluation are shared. © The Author(s) 2022

Design and characterization of a compact single-layer multibeam array antenna using an 8×8 Butler matrix for 5G base station applications

A multibeam array antenna employing a Butler matrix is a promising solution for fifth generation (5G) base stations. Due to inaccurate phase differences between output ports in the Butler matrix, the radiation characteristics could show incorrect main beam directions. In addition, the literature has also reported the issue of high amplitude imbalance in the Butler matrix. This paper presents a single-layer multibeam array antenna fed by an 8×8 Butler matrix operating at 28 GHz for 5G base station applications-a more cost-effective solution for large-scale production. The Butler matrix consists of twelve quadrature hybrids, sixteen crossovers, and eight phase shifters. This circuit was integrated with eight antenna elements at the output ports of the Butler matrix. The proposed multibeam array antenna was fabricated using a low dielectric constant and a low loss tangent substrate. The dimensions of the multibeam array antenna were 88×106×0.254 mm3 . The Butler matrix achieved low insertion losses and low phase error with average values of 2.5 dB and less than ±10 ° at 28 GHz, respectively. The measured return losses were less than -10 dB at 28 GHz. The measured radiation patterns were obtained and eight main beams were pointed at ±6 ° , ±18 ° , ±30 ° , and ±44 ° with measured gains between 9 dBi and 14 dBi

Untersuchungen zum Einfluss von thrombozytären Wachstumsfaktoren auf den zellvermittelten Abbau eines nanopartikulären Knochenersatzstoffes auf Hydroxylapatitbasis : eine experimentelle Studie am Miniaturschwein

Ziel der vorliegenden tierexperimentellen Studie am Miniaturschwein war es, den Einfluss von plättchenreichem Plasma (PRP) auf den zellvermittelten Abbau eines nanopartikulären Hydroxylapatits (HA) in der Frühphase der Knochendefektheilung zu untersuchen. Hierzu wurden 26 männliche Miniaturschweine der Rasse Mini-Lewe in drei Versuchsgruppen eingeteilt und jeweils ein standardisierter Knochendefekt in der Intercondylarregion des rechten Femurs angelegt. Die Defekte wurden entweder mit dem Knochenersatzstoff (Gruppe I/PRP-,n = 11) oder dem Knochenersatzstoff kombiniert mit PRP (Gruppe II/PRP+, n = 11) befüllt. In einer Kontrollgruppe (n = 4) blieben die Defekte unbefüllt. Während der Implantationsoperation wurden bei sechs Tieren jeweils 250 ml Vollblut entnommen, aus dem anschließend durch fraktionierte Zentrifugation plättchenreiches Plasma gewonnen wurde. Die enthaltenen Thrombozyten wurden durch den Zusatz von Thrombin und Kalziumglukonat zur Degranulation angeregt, wodurch die enthaltenen Wachstumsfaktoren aus den alpha-Granula freigesetzt wurden. Zu diesen Wachstumsfaktoren gehören Platelet Derived Growth Factor AB und BB (PDGF AB, BB), Transforming Growth Factor ß 1 (TGF beta1), Vascular Endothelial Growth Factor (VEGF) und basic Fibroblast Growth Factor (bFGF). Die Konzentration der genannten Wachstumsfaktoren wurde mit Hilfe der ELISA-Technik bestimmt. Sie lagen zwischen Faktor 1,6 für TGF-beta1 und Faktor 24,4 für bFGF. 20 Tage post operationem fand die Explantation der operierten distalen Femura statt. Zur lichtmikroskopischen Untersuchung fanden die Knochen-Implantat-Proben Eingang in unterschiedliche Techniken der Einbettung (Paraffin-, Kunststoffeinbettungen), Präparation (Paraffinschnitte, Kunststoffschnitte und Schliffpräparationen), Färbung (Toluidinblau, Haematoxylin-Eosin, Safranin) und Histochemie (Enzym-, Immunhistochemie). Darüber hinaus wurden transmissionselektronenmikroskopische und computergestützte histomorphometrische Untersuchungen durchgeführt. Wie die Ergebnisse der Licht- und Transmissionselektronenmikroskopie aufgezeigt haben, erfolgt in den mit Knochenersatzmaterial behandelten Versuchsgruppen, unabhängig von der PRP-Applikation, die HA-Degradation hydrolytisch und Makrophagen-vermittelt. Die Makrophagen-Population wird durch Riesenzellen vom Langhans-Typ repräsentiert. Diese polarisierten Polykaryen adhärieren über ihre apikale Membrandomäne an den Implantatoberflächen. Das subplasmalemmale Zytoplasma ist immunhistochemisch durch Vimentin-Kondensationen gekennzeichnet. Nicht-adhärente, frei im Granulationsgewebe lokalisierte Polykaryen zeigen dagegen ein homogenes Vimentin-Verteilungsmuster im Zytoplasma. Der zelluläre Abbau des HA erfolgt mittels Phagozytose, indem die Polykaryen den "Fremdkörper" mit pseudopodienartigen Zytoplasmaausläufern umschließen und in ihr Zytoplasma inkorporieren. Diese Art der Degradation wird durch den post implantationem stattfindenden Zerfall des Knochenersatzmaterials in zahlreiche kleine Partikel unterstützt. Die hieraus resultierende Vergrößerung der Implantatoberfläche bietet einer Vielzahl von Zellen die Möglichkeit zur Haftung. Die festgestellten Expressionsmuster des CD44- Membranglykoproteins verweisen auf dessen funktionelle Rolle im Rahmen der Fusion mononukleärer Makrophagen zu multinukleären Riesenzellen. Die darüber hinaus beobachtete Umverteilung von CD44 von der apikalen zur basalen Membrandomäne bei Implantatassoziierten Polykaryen ist als transientes Geschehen im Zuge der Adhäsion zu interpretieren. Der hohe Aktivitätsstatus der adhärenten Polykaryen ist immunhistochemisch durch eine intensive Kathepsin K-Expression gekennzeichnet. Die vergleichende histomorphometrische Auswertung der mit HA aufgefüllten Defekte dokumentiert eine Verdopplung der Anzahl von Polykaryen in der Gruppe "Knochenersatzstoff mit PRP". Ein auf Basis der Messergebnisse durchgeführter Wilcoxon-Rangsummentest verweist auf den hochsignifikanten Einfluss (p < 0,01) des Faktors PRP auf die Ausdehnung Tartrat-resistenter saurer Phosphatase-positiver Areale in den Präparaten. Diese Effekte können sowohl auf den im PRP angereicherten Wachstumsfaktoren als auch auf dem homologen Charakter der PRP-Zubereitung beruhen. Die beobachteten Polykaryen – sogenannte "Fremdkörperriesenzellen" – sind auch immer Indikatoren einer stattfindenden Entzündungsreaktion. Die histomorphometrisch dargestellte, deutlich verstärkte Fremdkörperreaktion in Gruppe II/PRP+ kann auf die PRP-Applikation zurückgeführt werden. Im weiteren Heilungsverlauf kann dies zu einer Verzögerung der knöchernen Konsolidierung der Defekte führen.Aim of the current experimental study in Minipigs was to examine the effects of homologous platelet-rich plasma (PRP) on the cell-mediated degradation of a nanoparticulate hydroxyapatite (HA) during the early phase of bone defect healing. Twenty-six male "Lewe" minipigs were divided into three groups. Standardized bone defects were created in the intercondylar region of the right femur of each pig and were filled with HA (Group I/PRP-, n = 11) or HA + PRP (Group II/PRP+, n = 11). The defects of the control group (n = 4) were left empty. During the implantation procedure blood was drawn from six minipigs (250 ml each). PRP was isolated from these blood samples after several centrifugation steps. After the addition of thrombin and calcium gluconate growth factors were released from the alpha-granules of the thrombocytes which were enriched within the PRP. Some of these growth factors are Platelet Derived Growth Factor AB and BB (PDGF AB, BB), Transforming Growth Factor ß 1 (TGF beta1), Vascular Endothelial Growth Factor (VEGF) and basic Fibroblast Growth Factor (bFGF). The level of enrichment of these growth factors was controlled by the ELISA technique. Growth factor enrichment within the PRP ranged from 1.6 fold (TGF-beta1) to 24.4 fold (bFGF). After 20 days the treated distal femura were explanted. For light microscopical examination different tissue embedding methods (paraffine, plastic, resin), sectioning techniques (paraffine sections, plastic and resin sections, sawing and grinding sections), staining procedures (toluidine blue, hematoxylin eosin, safranin) and histochemical methods (enzyme- and immunohistochemistry) were performed. Additionally transmission electron microscopy and computer-assisted histomorphometry were used. The results of light microscopy and transmission electron microscopy showed that regardless of the addition of PRP, the HA is degraded by hydrolysis and macrophages. The population of macrophages consists of Langhans-type giant cells. The adhesion of the polarized polykaryons at the surfaces of the implant is mediated by the apical domain of the plasmamembranes. Vimentin condensations of the cytoplasm are attached to the apical plasmalemma. In contrast, non-adherent polykaryons of the granulation tissue reveal a homogeneous Vimentin distribution pattern within their cytoplasma. As shown ultrastructurally, the implant is degraded by means of phagocytosis. The implant particles are encircled by pseudopodia of the polykaryons and become incorporated into the cytoplasma. The degradation process is supported by disintegration of the bone substitute into numerous small particles after implantation. This disintegration causes enlargement of the implant surface and increases the probability of phagocyte adhesion. The pattern of CD44 expression points towards a functional role of the molecule during fusion of mononucleated macrophages into multinucleated giant cells. Implant-associated polykaryons show CD44 immunoreactivity only along the basal domains of the cytomembrane. This pattern can be interpreted as a temporal event during adhesion. Adherent polykaryons are further characterized by strong cathepsin K expression. The histomorphometric examination demonstrates twice as much foreign body giant cells in "Group II/PRP+" as in "Group I/PRP-". Based on these results, a Wilcoxon-signed-rank test was performed and a highly significant effect (p < 0.01) of PRP on the expansion of tartrate resistent acid phophatase (TRAP)-positive areas within bone defects could be demonstrated. This effect could be a result of the substution of PRP or of its homologous character. The polykaryons descibed in this work - so-called Foreign Body Giant Cells - are also indicators of inflammation. The enhanced cellular reaction observed in Group II/PRP+ must be interpreted as a strong foreign body reaction, triggered by the addition of PRP. It cannot be excluded that the strong inflammation reaction will lead to delayed bone formation in the course of healing

Does the stock market reward innovation? European stock index reaction to negative news during the global financial crisis

This study uses data on 27 European stock indices over the period from January 2007 to December 2012 to investigate the relationship between innovations and the market reaction to negative news during the financial crisis. We use the bivariate BEKK-GARCH approach to estimate time-varying betas and abnormal returns. We show that index prices of countries in the high (low) innovation groups experience significantly positive (negative) abnormal returns on and following the negative news announcement dates. We also find that index beta changes following the arrival of bad news is negatively associated with a country's innovativeness. This finding suggests that innovations promote economic stability and enhance investors' confidence in a country's ability to cope during difficult times. Thus, policy makers who are concerned with sustainable growth should encourage R&D investments by adopting effective policies and avoid unnecessary cuts in R&D expenditures even during times of crisis. A study of the pre-crisis period from January 2001 to December 2006, using the same methods, indicates that investors value innovation more during difficult times

Imbalanced-learn: A Python Toolbox to Tackle the Curse of Imbalanced Datasets in Machine Learning

International audienceimbalanced-learn is an open-source python toolbox aiming at providing a wide range of methods to cope with the problem of imbalanced dataset frequently encountered in machine learning and pattern recognition. The implemented state-of-the-art methods can be categorized into 4 groups: (i) under-sampling, (ii) over-sampling, (iii) combination of over-and under-sampling, and (iv) ensemble learning methods. The proposed toolbox depends only on numpy, scipy, and scikit-learn and is distributed under MIT license. Furthermore , it is fully compatible with scikit-learn and is part of the scikit-learn-contrib supported project. Documentation, unit tests as well as integration tests are provided to ease usage and contribution. Source code, binaries, and documentation can be downloaded from https://github.com/scikit-learn-contrib/imbalanced-learn

Combining Prototype Selection with Local Boosting

Part 2: Classification – Pattern Recognition (CLASPR)International audienceReal life classification problems require an investigation of relationships between features in heterogeneous data sets, where different predictive models can be more proper for different regions of the data set. A solution to this problem is the application of the local boosting of weak classifiers ensemble method. A main drawback of this approach is the time that is required at the prediction of an unseen instance as well as the decrease of the classification accuracy in the presence of noise in the local regions. In this research work, an improved version of the local boosting of weak classifiers, which incorporates prototype selection, is presented. Experimental results on several benchmark real-world data sets show that the proposed method significantly outperforms the local boosting of weak classifiers in terms of predictive accuracy and the time that is needed to build a local model and classify a test instance

Increasing Diversity in Random Forests Using Naive Bayes

Part 2: Classification – Pattern Recognition (CLASPR)International audienceIn this work a novel ensemble technique for generating random decision forests is presented. The proposed technique incorporates a Naive Bayes classification model to increase the diversity of the trees in the forest in order to improve the performance in terms of classification accuracy. Experimental results on several benchmark data sets show that the proposed method archives outstanding predictive performance compared to other state-of-the-art ensemble methods

Wideband power amplifier for two-way radio applications via real-frequency technique

The requirements of two-way radio applications in the wideband operating frequency are stringent, particularly for the power amplifier (PA) design. A novel design method for a wideband PA matching network for two-way radio applications is proposed. The design method begins with identifying an initial guess of the matching network from the theoretical analysis, followed by a practical design methodology to realise the design in the compact form factor and low cost implementation. Experimental results demonstrated an output power of similar to 7 W and an efficiency of about 65%, demonstrated high power performance (including stable operation and ruggedness) from 270 to 560 MHz running at a low DC supply of 7.2 V (with LDMOS device technology)

Molecular Catalysis

The present work reports on the use of a hybrid blend of biopolymers as a matrix for lipase immobilization. (Hydroxypropyl)methyl cellulose (HPMC) and Chitosan (CS) were combined in order to formulate a film on which Mucor miehei lipase was immobilized. The biocatalyst was studied upon the model reaction of propyl laurate synthesis. The system was examined in terms of its capability to provide an appropriate environment where lipase will maintain its activity. The ratio of the polymers used was examined and HPMC:CS=2:1 proved to form the most promising matrix. Increasing the amount of the immobilized enzyme appears to improve the reaction yield indicating, however, mass transfer limitations. Apparent activation energy was calculated and energy input showed that ultra-sonication accelerated the initial rate of the reaction. Different reaction solvents were tested with isooctane being the most effective. The enzyme-containing film showed a remarkable reusability, since it can be used for up to 35 times without loss of activity. Finally, Atomic Force Microscopy (AFM) was performed to observe the morphology of the most promising films. The HPMC/CS film exhibits a nanostructure without a unique characteristic length and a roughness of 42.8 nm while the presence of enzyme smoothens the film as the roughness decreases to 5.5 nm