Controlled electroporation of the plasma membrane in microfluidic devices for single cell analysis

Chemical cytometry on a single cell level is of interest to various biological fields ranging from cancer to stem cell research. The impact chemical cytometry can exert in these fields depends on the dimensionality of the retrievable analytes content. To this point, the number of different analytes identifiable and additionally their subcellular localization is of interest. To address this, we present an electroporation based approach for selective lysis of only the plasma membrane, which permits analysis of the dissolved cytoplasm, while reducing contributions from the nucleus and membrane bound fractions of the cell analytes. The use of 100 μs long pulse and a well defined DC electric field gradient of ∼4.5 kV·cm⁻¹ generated by 3D electrodes initiates release of a cytoplasm marker in ≪1 s, while retaining nuclear fluorescence markers.     

Enhancing Scientific Communication Skills: a Real-World Simulation in a Tertiary-Level Life Science Class Using E-Learning Technology in Biomedical Literature Perception,Reflective Review Writing on a Clinical Issue,and Self and Peer Assessments

Research in Science Education - This educational study aimed to explore the feasibility and acceptance of a literacy exercise adopted from the realworld of scientific publishing in a cell and...     

Concept Mapping Assessment of Media Assisted Learning in Interdisciplinary Science Education

Acquisition of conceptual knowledge is a central aim in science education. In this study we monitored an interdisciplinary hypermedia assisted learning unit on hibernation and thermodynamics based on cooperative learning. We used concept mapping for the assessment, applying a pre-test/post-test design. In our study, 106 9th graders cooperated by working in pairs (n = 53) for six lessons. As an interdisciplinary learning activity in such complex knowledge domains has to combine many different aspects, we focused on long-term knowledge. Learners working cooperatively in dyads constructed computer-supported concept maps which were analysed by specific software. The data analysis encompassed structural aspects of the knowledge corresponding to a target reference map. After the learning unit, the results showed the acquisition of higher-order domain-specific knowledge structures which indicates successful interdisciplinary learning through the hypermedia learning environment. The benefit of using a computer-assisted concept mapping assessment for research in science education, and in science classrooms is considered.     

Relationships between performance test and match-related physical performance parameters

Background

The purpose of this study was to analyze the relationship between performance test parameters and match-related physical performance in professional soccer players.

Methods

To determine physical capacity, 28 male soccer players underwent several performance tests at the start of the seasons 2013/2014, 2014/2015, and 2015/2016. The following parameters were assessed: maximum running velocity (v_max), fixed (v_4mmol/l) and individual anaerobic threshold (v_IAS) during an incremental treadmill test; 30-m sprint time in a linear sprint test (LS_30m); in a repeated-sprint test, the 30-m sprint time (RST_30m) and performance decrement (RST_decr); and countermovement jump height (CMJ). Match physical performance was quantified during the first ten official matches of each season using a computerized, camera-based tracking system. The following measures of match physical performance were considered: top running speed (TS), mean running speed (v_Ø), total distance covered (TD), number of sprints (SP), number of high-intensity running (HIR), and aerial duels won (AD+). Pearson correlation coefficients were used for statistical analysis.

Results

Moderate to very large correlations were found between the majority of performance test parameters and match performance variables, with a variability of correlations across the three seasons. Large relationships across all three seasons were only observed between v_max and TD, v_max and v_Ø, LS_30m and TS as well as RST_30m and TS.

Conclusion

This study demonstrates the relationship between several performance test parameters and match-related physical performance in professional soccer players, thereby supporting the test parameters’ criterion validity. v_max, LS_30m, and RST_30m seem to be the most consistent parameters.

     

The Cavendish Experiment as a Tool for Historical Understanding of Science

Following an ever growing literature which takes serious the relevance of case-studies in the history of science for science education and understanding of science, I provide a detailed historical reconstruction of the Cavendish Experiment, which remains as close as possible to the original. In this paper, I call attention to three educational benefits of familiarizing students with the Cavendish Experiment and its aftermath.     

Entwurf und Implementierung eines SQL-normkonformen Datenbankkatalogs für ein relationales Datenbankmanagementsystem

Bei relationalen Datenbanksystemen haben sich de-jure-Normen für SQL stetig weiterentwickelt; mit diesen Normen wird es einfacher, portable Datenbankanwendungen zu entwickeln. Die SQL-Norm ruht auf zwei S?ulen, zum einen auf der Datenbanksprache SQL, zum anderen auf einer Vorgabe eines Datenbankkatalogs, welcher die gespeicherten Daten beschreiben soll. Im vorliegenden Beitrag wird derjenige Teilbereich des Datenbankkatalogs der aktuellen SQL99-Norm dargestellt, der bereits in der SQL92-Norm (ISO/IEC 9075:1992 bzw. DIN 66315) definiert ist und die klassischen (nicht objektrelationalen) Elemente einer relationalen Datenbank beschreibt. In dieser Darstellung nimmt der zweischichtige Spezifikationsansatz (Informationsschema, Definitionsschema) einigen Raum ein; mit seiner Hilfe weist SQL einen eleganten Weg, auf dem existierende Datenbanksysteme normkonforme Datenbankkataloge bereitstellen k?nnen. Anhand des Datenbankmanagementsystems DB2 wird anschlie?end untersucht, wie ein normkonformer Datenbankkatalog (das sogenannte Informationsschema) „oberhalb” des verfügbaren DB2-Katalogs realisiert werden kann, d. h. wie die vom Informationsschema geforderten Sichten auf DB2-Katalogtabellen abgebildet werden k?nnen. Auf generelle Schwierigkeiten und M?glichkeiten einer solchen Abbildung (ein- oder zweistufig) wird ebenso eingegangen wie auf Probleme, die sich speziell bei DB2 ergeben. In einer prototypischen Realisierung konnte das Informationsschema bis auf wenige Einschr?nkungen komplett umgesetzt werden. Damit wurde die Machbarkeit normkonformer Kataloge nachgewiesen. In heute verfügbaren DBMS-Produkten sind Datenbankkataloge in dieser konsequent normkonformen Gestalt leider immer noch nicht anzutreffen.     

Building a technology foundation for future teachers

It is fitting that the teachers of tomorrow are provided with the correct modeling of technology in their first education class. To separate technology from education is both impossible and foolish. The sooner college students are exposed to the latest forms of technology, the more equipped they will be to integrate these tools into their teaching strategies for the benefit of future learners.     

Should Regularization Replace Simple Structure Rotation in Exploratory Factor Analysis?

Exploratory factor analysis (EFA) is an important tool when the measurement structure of psychological constructs is uncertain. Typically, factor rotation is applied to obtain interpretable results resembling a simple structure. However, an overwhelming multitude of rotation techniques is available of which none is unequivocally superior. Recently, regularization has been suggested as an alternative to factor rotation. In two simulation studies, we addressed the question if regularized EFA is a suitable alternative for rotated EFA. We compared their performance in recovering predefined factor loading patterns with varying amounts of cross-loadings. Elastic net regularized EFA yielded estimates comparable to rotated EFA. For complex loading patterns, both rotated and regularized EFA tended to underestimate cross-loadings and inflate factor correlations, but regularized EFA was able to recover loading patterns as long as a subset of items followed a simple structure. We conclude that regularization is a suitable alternative to factor rotation for psychometric applications.