Toward Continuous Molecular Testing Using Gold-Coated Threads as Multi-Target Electrochemical Biosensors.

Analytical systems based on isothermal nucleic acid amplification tests (NAATs) paired with electroanalytical detection enable cost-effective, sensitive, and specific digital pathogen detection for various in situ applications such as point-of-care medical diagnostics, food safety monitoring, and environmental surveillance. Self-assembled monolayers (SAMs) on gold surfaces are reliable platforms for electroanalytical DNA biosensors. However, the lack of automation and scalability often limits traditional chip-based systems. To address these challenges, we propose a continuous thread-based device that enables multiple electrochemical readings on a functionalized working electrode Au thread with a single connection point. We demonstrate the possibility of rolling the thread on a spool, which enables easy manipulation in a roll-to-roll architecture for high-throughput applications. As a proof of concept, we have demonstrated the detection of recombinase polymerase amplification (RPA) isothermally amplified DNA from the two toxic microalgae species Ostreopsis cf. ovata and Ostreopsis cf. siamensis by performing a sandwich hybridization assay (SHA) with electrochemical readout.

Portable electroanalytical nucleic acid amplification tests using printed circuit boards and open-source electronics.

The realization of electrochemical nucleic acid amplification tests (NAATs) at the point of care (POC) is highly desirable, but it remains a challenge given their high cost and lack of true portability/miniaturization. Here we show that mass-produced, industrial standardized, printed circuit boards (PCBs) can be repurposed to act as near-zero cost electrodes for self-assembled monolayer-based DNA biosensing, and further integration with a custom-designed and low-cost portable potentiostat. To show the analytical capability of this system, we developed a NAAT using isothermal recombinase polymerase amplification, bypassing the need of thermal cyclers, followed by an electrochemical readout relying on a sandwich hybridization assay. We used our sensor and device for analytical detection of the toxic microalgae Ostreopsis cf. ovata as a proof of concept. This work shows the potential of PCBs and open-source electronics to be used as powerful POC DNA biosensors at a low-cost.

Arrogant or caring? Influence of transactive communication in interprofessional learning on knowledge gains and stereotype changes.

Objective: In interprofessional peer tutoring, medical students and physiotherapy trainees teach and practice examination techniques and work out profession-specific similarities and differences. In small interprofessional groups, we investigated the influence of transactive communication - alternately referring to and building on the statements made by the dialogue partner in the process of conveying information - on knowledge gains and changes in stereotypes of the other profession. Methods: A total of 132 medical students and 48 physiotherapy trainees divided into 24 small interprofessional groups indicated the extent of their stereotypes of the other profession before and after the practice session, as well as their perceived increase in knowledge. They evaluated the group work and the perceived intensity of transactive communication. We used regression analyses to test the hypotheses. Results: The intensity of transactive communication in the physiotherapy trainees was positively related to knowledge gains in the medical students. However, this did not apply to the knowledge gains in physiotherapy trainees. With regard to stereotype changes, the intensity of one's own transactive communication unexpectedly turned out to be a significant, albeit weak, influencing factor: The more intensive one's own transactive communication was, the more negative the stereotypes of the other profession became. Conclusion: Transactive communication in interprofessional groups can improve the exchange of knowledge in peer tutoring and bring about changes in stereotypes. Measures to improve transactive communication, e.g. training sessions or specific communication exercises, could help to improve the effectiveness of interprofessional learning.

Electrochemical Detection of Genomic DNA Utilizing Recombinase Polymerase Amplification and Stem-Loop Probe.

Nucleic acid tests integrated into digital point-of-care (POC) diagnostic systems have great potential for the future of health care. However, current methods of DNA amplification and detection require bulky and expensive equipment, many steps, and long process times, which complicate their integration into POC devices. We have combined an isothermal DNA amplification method, recombinase polymerase amplification, with an electrochemical stem-loop (S-L) probe DNA detection technique. By combining these methods, we have created a system that is able to specifically amplify and detect as few as 10 copies/µL Staphylococcus epidermidis DNA with a total time to result of 70-75 min.

Generating Causal Relations in Scientific Texts: The Long-Term Advantages of Successful Generation.

A high level of text comprehension can be achieved by engaging learners in processes of organization and integration while reading a cohesive text. In the present study, we investigated the impact of an innovative generative technique on learning with scientific texts. The cohesion generation was implemented by means of explicit cohesion gaps. High school students (n = 199) were randomly assigned to either receive a fully cohesive scientific text (control condition) or a scientific text that required the selection of causal connectives, such as because, although, therefore, or however (generation condition). Learners in the generation condition were required to reflect on causal relations to complete the text. All students were tested immediately (T1) and 2 weeks after the learning phase (T2). Cognitive load was measured by a dual task and self-report measure. Contrary to our expectations, no differences were found in performance on inference questions (situation model). Learners in the generation condition performed worse on text-based questions at T1 but showed less forgetting from T1 to T2. The impact of condition on the situation model was moderated by reading skills. Remarkably, the generation success was highly predictive for learning outcomes even when controlling for learners' proficiencies. Consequently, learners who succeeded to employ effortful processes to overcome the difficulty showed a superior performance on both the text-base and situation-model questions compared to students reading the cohesive text. Moreover, in these learners, generative activity led to a sustainable learning performance 2 weeks later. Poor readers especially took advantage of generative activity, despite struggling to perform the cohesion task as indicated by the cognitive load measures. The results suggest that the activity of generating causal relations can augment inferential processing in learners who are not involved in inferential processing spontaneously. To successfully apply this generative learning technique, students require considerable instructional support.

How to increase the benefits of cooperation: Effects of training in transactive communication on cooperative learning.

BACKGROUND: Transactive communication means referring to and building on a learning partner's idea, by, for example, extending the partner's idea or interlinking the partner's idea with an idea of one's own. This transforms the partner's idea into a more elaborate one. Previous research found a positive relationship between students' transactive communication and their learning results when working in small groups. AIMS: To increase the benefits of cooperation, we developed and tested a module for training students in transactive communication. We assumed that this training would enhance students' transactive communication and also increase their knowledge acquisition during cooperative learning. Further, we distinguished between an actor's transactive communication and a learning partner's transactive communication and expected both to be positively associated with an actor's knowledge acquisition. SAMPLE: Participants were 80 university students. METHODS: In an experiment with pre- and post-test measurements, transactive communication was measured by coding students' communication in a cooperative learning situation before training and in another cooperative learning situation after training. For the post-test cooperative learning situation, knowledge was pre-tested and post-tested. RESULTS: Trained students outperformed controls in transactive communication and in knowledge acquisition. Positive training effects on actors' knowledge acquisition were partially mediated by the improved actors' transactive communication. Moreover, actors' knowledge acquisition was positively influenced by learning partners' transactive communication. CONCLUSIONS: Results show a meaningful increase in the benefits of cooperation through the training in transactive communication. Furthermore, findings indicate that students benefit from both elaborating on their partner's ideas and having their own ideas elaborated on.

Simultaneous targeting of two ligand-binding sites on VEGFR2 using biparatopic Affibody molecules results in dramatically improved affinity.

Angiogenesis plays an important role in cancer and ophthalmic disorders such as age-related macular degeneration and diabetic retinopathy. The vascular endothelial growth factor (VEGF) family and corresponding receptors are regulators of angiogenesis and have been much investigated as therapeutic targets. The aim of this work was to generate antagonistic VEGFR2-specific affinity proteins having adjustable pharmacokinetic properties allowing for either therapy or molecular imaging. Two antagonistic Affibody molecules that were cross-reactive for human and murine VEGFR2 were selected by phage and bacterial display. Surprisingly, although both binders independently blocked VEGF-A binding, competition assays revealed interaction with non-overlapping epitopes on the receptor. Biparatopic molecules, comprising the two Affibody domains, were hence engineered to potentially increase affinity even further through avidity. Moreover, an albumin-binding domain was included for half-life extension in future in vivo experiments. The best-performing of the biparatopic constructs demonstrated up to 180-fold slower dissociation than the monomers. The new Affibody constructs were also able to specifically target VEGFR2 on human cells, while simultaneously binding to albumin, as well as inhibit VEGF-induced signaling. In summary, we have generated small antagonistic biparatopic Affibody molecules with high affinity for VEGFR2, which have potential for both future therapeutic and diagnostic purposes in angiogenesis-related diseases.