A novel experimental procedure based on pure shear testing of dermatome-cut samples applied to porcine skin

This paper communicates a novel and robust method for the mechanical testing of thin layers of soft biological tissues with particular application to porcine skin. The key features include the use of a surgical dermatome and the highly defined deformation kinematics achieved by pure shear testing. Thin specimens of accurate thickness were prepared using a dermatome and were subjected to different quasi-static and dynamic loading protocols. Although simple in its experimental realisation, pure shear testing provides a number of advantages over other classic uni- and biaxial testing procedures. The preparation of thin specimens of porcine dermis, the mechanical tests as well as first representative results are described and discussed in detail. The results indicate a pronounced anisotropy between the directions along and across the cleavage lines and a strain rate-dependent respons

Володимир Антонович і Дмитро Яворницький: до історії наукових і особистих взаємин

Невід’ємною складовою інтелектуальної історії є дослідження міжособистісних стосунків науковців. Особливо, якщо кожен із них є знаковою постаттю, уособленням поєднання високого професіоналізму і патріотичної громадянської позиції. Дослідження останнього часу, присвячені В.Б.Антоновичу визначають його безперечно новаторську місію у складанні першої науково доказової національно-демократичної концепції минулого України та розробленні періодизації вітчизняного історичного процесу

Overview of Licensing Platforms based on Distributed Ledger Technology

The licensing of creative work is of broad and current interest. The European Commission proposes that when uploading a licensed digital work, the uploader should be checked by the system that one has the necessary rights. Technically this law is difficult to implement, as images with different intentions are shared, and even small changes like watermarks make it difficult to reveal similarities. The characteristics of distributed ledger technology could provide excellent support for the licensing and management of the rights of use. In this work, non-technical and technical criteria are defined to achieve an overview of the state-of-the-art solutions in the field of blockchain-based licensing platforms. Based on the criteria, different licensing platforms are reviewed, and the results are presented in a comparison matrix

Continual Learning in Recurrent Neural Networks with Hypernetworks

The last decade has seen a surge of interest in continual learning (CL), and a variety of methods have been developed to alleviate catastrophic forgetting. However, most prior work has focused on tasks with static data, while CL on sequential data has remained largely unexplored. Here we address this gap in two ways. First, we evaluate the performance of established CL methods when applied to recurrent neural networks (RNNs). We primarily focus on elastic weight consolidation, which is limited by a stability-plasticity trade-off, and explore the particularities of this trade-off when using sequential data. We show that high working memory requirements, but not necessarily sequence length, lead to an increased need for stability at the cost of decreased performance on subsequent tasks. Second, to overcome this limitation we employ a recent method based on hypernetworks and apply it to RNNs to address catastrophic forgetting on sequential data. By generating the weights of a main RNN in a task-dependent manner, our approach disentangles stability and plasticity, and outperforms alternative methods in a range of experiments. Overall, our work provides several key insights on the differences between CL in feedforward networks and in RNNs, while offering a novel solution to effectively tackle CL on sequential data.Comment: 13 pages and 4 figures in the main text; 20 pages and 2 figures in the supplementary material

Multiscale mechanical analysis of the elastic modulus of skin

The mechanical properties of the skin determine tissue function and regulate dermal cell behavior. Yet measuring these properties remains challenging, as evidenced by the large range of elastic moduli reported in the literature-from below one kPa to hundreds of MPa. Here, we reconcile these disparate results by dedicated experiments at both tissue and cellular length scales and by computational models considering the multiscale and multiphasic tissue structure. At the macroscopic tissue length scale, the collective behavior of the collagen fiber network under tension provides functional tissue stiffness, and its properties determine the corresponding elastic modulus (100-200 kPa). The compliant microscale environment (0.1-10 kPa), probed by atomic force microscopy, arises from the ground matrix without engaging the collagen fiber network. Our analysis indicates that indentation-based elasticity measurements, although probing tissue properties at the cell-relevant length scale, do not assess the deformation mechanisms activated by dermal cells when exerting traction forces on the extracellular matrix. Using dermal-equivalent collagen hydrogels, we demonstrate that indentation measurements of tissue stiffness do not correlate with the behavior of embedded dermal fibroblasts. These results provide a deeper understanding of tissue mechanics across length scales with important implications for skin mechanobiology and tissue engineering. STATEMENT OF SIGNIFICANCE: Measuring the mechanical properties of the skin is essential for understanding dermal cell mechanobiology and designing tissue-engineered skin substitutes. However, previous results reported for the elastic modulus of skin vary by six orders of magnitude. We show that two distinct deformation mechanisms, related to the tension-compression nonlinearity of the collagen fiber network, can explain the large variations in elastic moduli. Furthermore, we show that microscale indentation, which is frequently used to assess the stiffness perceived by cells, fails to engage the fiber network, and therefore cannot predict the behavior of dermal fibroblasts in stiffness-tunable fibrous hydrogels. This has important implications for how to measure and interpret the mechanical properties of soft tissues across length scales

Assessing teamwork competence

Abstract. Background: In recent years, organizations of all types have undergone major changes, and teamwork is one of them. This way of working generates greater profits for an organization. This article aims to assess the teamwork competence of the employees of various Spanish companies in order to determine how effective the team members are in their professional actions. Method: We contacted 55 teams from different organizations and obtained a non-probabilistic sample comprised of 55 participants (subjects tested) and 218 observers (evaluators: coordinators and co-workers). The instrument used for data collection was the Teamwork Rubric (Torrelles, 2011) and data analysis was based on 360º feedback. Results: 80% of the teams analyzed obtained median scores for teamwork competence that were greater than 3, whereas 20% obtained scores between 2 and 3. Conclusions: The results showed that the workers in the companies studied had not fully acquired teamwork competence. It is necessary to find training solutions to improve their level of acquisition, particularly the dimensions of performance and regulation. Resumen: Evaluación de la competencia de trabajo en equipo. Antecedentes: En los últimos años las organizaciones han experimentado múltiples cambios y el trabajo en equipo es uno de ellos. Esta manera de trabajar genera más beneficio en las organizaciones. El presente artículo tiene como objetivo evaluar la competencia de trabajo en equipo de los empleados de diferentes empresas españolas para conocer las debilidades y potencialidades de los equipos en su acción profesional. Método: Se ha contactado con 55 equipos procedentes de diferentes organizaciones configurando así una muestra de carácter no probabilístico formada por 55 participantes (sujetos evaluados) y 218 observadores (sujetos evaluadores: coordinadores y compañeros de trabajo). El instrumento de recogida de los datos es la Rúbrica de Trabajo en Equipo (Torrelles, 2011) y su aplicación se ejecuta a través del método de evaluación 360º. Resultados: El 80% de los trabajadores muestran que tienen una media de 3 o superior en el nivel de adquisición de la competencia de trabajo en equipo, el 20% restante se encuentran entre 2 y 3. Conclusiones: Los resultados muestran que los trabajadores de las empresas españolas no tienen adquirida la competencia de trabajo en equipo en toda su globalidad, pues dimensiones como la regulación y la ejecución necesitan ser mejoradas

Intracranial Hemorrhage in Patients with Anticoagulant Therapy Undergoing Stereotactic Radiosurgery for Brain Metastases: A Bi-Institutional Analysis

Background: Stereotactic radiosurgery (SRS) is a well-established treatment modality for brain metastases (BM). Given the manifold implications of metastatic cancer on the body, affected patients have an increased risk of comorbidities, such as atrial fibrillation (AF) and venous thromboembolism (VTE), which includes pulmonary embolism (PE) and deep-vein thrombosis (DVT). These may require therapeutic anticoagulant therapy (ACT). Limited data are available on the risk of intracranial hemorrhage (ICH) after SRS for patients with BM who are receiving ACT. This bi-institutional analysis aimed to describe the bleeding risk for this patient subgroup. Methods: Patients with ACT at the time of single-fraction SRS for BM from two institutions were eligible for analysis. The cumulative incidence of ICH with death as a competing event was assessed during follow-up with magnetic resonance imaging or computed tomography. Results: Forty-one patients with 97 BM were included in the analyses. The median follow-up was 8.2 months (range: 1.7-77.5 months). The median and mean BM volumes were 0.47 and 1.19 cubic centimeters, respectively. The most common reasons for ACT were PE (41%), AF (34%), and DVT (7%). The ACT was mostly performed utilizing phenprocoumon (37%), novel oral anticoagulants (32%), or low-molecular-weight heparin (20%). Nine BM from a group of five patients with ICH after SRS were identified: none of them caused neurological or any other deficits. The 6-, 12-, and 18-month cumulative bleeding incidences per metastasis were 2.1%, 12.4%, and 12.4%, respectively. The metastases with previous bleeding events and those originating from malignant melanomas were found to more frequently demonstrate ICH after SRS (p = 0.02, p = 0.01). No surgical or medical intervention was necessary for ICH management, and no observed death was associated with an ICH. Conclusion: Patients receiving an ACT and single-fraction SRS for small- to medium-sized BM did not seem to have a clinically relevant risk of ICH. Previous bleeding and metastases originating from a malignant melanoma may favor bleeding events after SRS. Further studies are needed to validate our reported findings