Search

A time-dependent understanding of swelling characteristics and external stimuli behavior is crucial for the development and understanding of functional hydrogels. Magnetic resonance imaging (MRI) offers the opportunity to study three-dimensional (3D) soft materials nondestructively. This technique is already widely used as an image-based medical diagnostic tool and is applied here to evaluate complex structures of a hydrogel—a double network of chemically crosslinked casein enhanced with alginate—fabricated by 3D printing. When hydrogel disks immersed in four different liquid systems were analyzed, the material exhibited distinct system-dependent behavior characterized by rheological and mechanical measurements. Further material functionalization was achieved by macroscopic structuring of the hydrogel as an auxetic material based on a re-entrant honeycomb structure. MRI offers the advantage of monitoring overall changes in the area of the analyzed specimen and internal structural changes simultaneously. To assess the behavior of this complex structure, a series of short MRI measurements, each lasting 1.7 min, captured liquid diffusion and thus structural swelling behavior. A clear dependence of external and internal structural changes as a function of liquid properties causing these changes was observed. In conclusion, this approach might pave the way for prospective applications to monitor liquid diffusion into (e.g., vascularization) and swelling behavior of functional hydrogels.

Numerous pathogenic complications affect the skin and are preventable, such as skin cancer, microbial diseases, dermal irritations, and anaphylaxis. In this context, the correct use of skin products, including sunscreens and child makeup, is important for promoting skin health and preventing adverse health conditions.This study aimed to use educational and playful activities to promote skin health for students.This project was development in a municipal elementary school (Rio Grande do Sul State, Brazil). The interventions were divided into three moments. In the first day, a questionnaire was applied to find out the students' previous knowledge about photoprotection. On the second day, an intervention lecture was held addressing issues related to photoprotection and the use of makeup. Finally, we played educational and ludic games and after, the questionnaire was reapplied. This was done to evaluate these actions' effectiveness regarding photoprotection and record their habits by applying a structured questionnaire at the beginning and end of the activities.Students received positively and interacted significantly during all activities performed. Regarding the impact of this study, we observed that ten times more students considered using sunscreen as something important at the end of the project, as only 8.16% of participants knew what skin cancer was at the beginning of the experiment. After the educational activities, this number rose to 72.37%, and 92.86% of girls reported wearing makeup, with more than half being expired or unlabeled and only 21.6% being appropriate for child use.The measures demonstrated effectively improve students' level of information regarding skin cancer prevention and indicated that inappropriate habits concerning makeup use in childhood are quite common, demonstrating the importance of educational interventions for children, since can improve your health.

Recording the data necessary to assess the kinetics of a reaction can be labor-intensive. In this technology brief, we show a method to automate this task by utilizing parts of an ÄKTApurifier chromatography system to automatically take samples from a reaction vessel at predefined time intervals and place them in 96-well plates and also enable correlating the samples with in-line spectral data of the reaction solution. Automatic sampling can reduce experimental bottlenecks by enabling overnight reactions or a higher degree of parallelization. To demonstrate the feasibility of the method, we performed batch-PEGylation of lysozyme with varying conditions by changing the molar excess of the PEG reagent. We used analytical cation-exchange chromatography to analyze the samples taken during the batch reaction, determining the concentrations of the individual species present at each time step. Subsequently, we fitted a kinetic model on these data. Fitting the model to four different reaction conditions simultaneously yielded a regression coefficient of

Peptide ligands have great potential as selective agents for diagnostic imaging and therapeutic targeting of human cancers. A number of high-throughput assays for screening potential candidate peptides have been developed. Although these screening assays are indispensable for the identification of peptide ligands at a large scale, it is crucial to validate peptide binding and selectivity for targeted receptors in a live-cell context. For testing high-affinity peptide-receptor interactions in the plasma membrane of living cells, we developed cell-resistant, micro-structured glass surfaces with high-density and high-contrast peptide features. Cell adhesion and recruitment of fluorescent receptors to micro-patterned peptides in the live-cell membrane were evaluated by reflection interference contrast (RIC) and total internal reflection (TIRF) microscopy, respectively. To demonstrate both the specificity and modularity of the assay, co-patterning of fluorescent receptors with three different immobilized micro-structured ligands was shown: first, interaction of green fluorescent protein (GFP)-tagged epidermal growth factor (EGF) receptor expressed in Jurkat cells with immobilized EGF was detected and quantified. Second, using Jurkat cells, we demonstrated specific interaction of yellow fluorescent protein (YFP)-tagged β3 integrin with c(RGDfK) peptide. Third, we identified indirect recruitment of GFP-tagged α5 integrin to an 11-mer peptide. In summary, our results show that the developed micro-structured surfaces are a useful tool for the validation and quantification of peptide-receptor interactions in their natural cellular environment.

Peptide and protein micropatterns are powerful tools for the investigation of various cellular processes, including protein&ndash, protein interactions (PPIs). Within recent years, various approaches for the production of functional surfaces have been developed. Most of these systems use glass as a substrate, which has several drawbacks, including high fragility and costs, especially if implemented for fluorescence microscopy. In addition, conventional fabrication technologies such as microcontact printing (&micro, CP) are frequently used for the transfer of biomolecules to the glass surface. In this case, it is challenging to adjust the biomolecule density. Here, we show that cyclic olefin polymer (COP) foils, with their encouraging properties, including the ease of manufacturing, chemical resistance, biocompatibility, low water absorption, and optical clarity, are a promising alternative to glass substrates for the fabrication of micropatterns. Using a photolithography-based approach, we generated streptavidin/biotinylated antibody patterns on COPs with the possibility of adjusting the pattern contrast by varying plasma activation parameters. Our experimental setup was finally successfully implemented for the analysis of PPIs in the membranes of live cells via total internal reflection fluorescence (TIRF) microscopy.

Lebenslanges Lernen und berufliche Weiterbildung stellen heute ein fast unabdingbares Element in der Berufsweg- und Karriereplanung dar. Eine zentrale Voraussetzung für erfolgreiches lebenslanges Lernen ist u. a. die individuelle Selbstlernfähigkeit. Führt man sich dagegen die an deutschen Hochschulen (noch) dominierenden informativen kollektiven Lernphasen vor Auge, so ist kritisch zu hinterfragen, ob die Selbstlernfähigkeiten der Studierenden zur Vorbereitung auf ein lebenslanges Lernen in einem ausreichenden Maße gefördert und eingefordert werden. Der Beitrag stellt erste Ergebnisse eines Lehr-/Lernexperiments zur Intensivierung von Selbstlernphasen im BA-Studium vor. Ziel war es, die Möglichkeiten und Grenzen von Selbstlernphasen mit Unterstützung von E-Assessments als individuelle Lernfortschrittskontrolle auszuloten. Nowadays lifelong learning and professional training are essential elements in career planning. Hereby the ability to learn independently is one of the main prerequisite for lifelong learning. Looking at the prevalent form of informative collective learning phases at German universities, one must critically questioning, if we foster and demand the ability to learn independently to a sufficient degree. This paper presents initial results of a teaching/learning experiment, investigating a noticeable increase of self-study phases in a Bachelor’s course. The aim was to assess possibilities and limitations of self-study phases in combination with E-Assessments as a form of monitoring of the progress of learning individually.

Pop-up stores are considered an alternative or a further development of the pioneering flagship store concept. They describe a temporary store concept that displays products in an unexpected way to attract the consumers’ attention (Hutter 2013). So far, this store format has mainly been applied to the USA and the UK, and has been insufficiently studied. This paper summarizes interim results of a pilot study on pop-up stores, which focuses on identifying factors for their success. Pop-up Stores stellen eine konzeptionelle Weiterentwicklung von Flagship Stores dar. Pop-Up Stores beschreiben ein zeitlich limitiertes Storekonzept, bei dem Produkte in einer ungewöhnlichen und finanziell erschwinglichen Art und Weise dem Kunden präsentiert werden (Hutter 2013). Bislang wird dieses neuartige Storekonzept überwiegend in den USA und in UK praktiziert und wissenschaftlich diskutiert. Der vorliegende Beitrag fasst erste Zwischenergebnisse einer Pilotstudie zu den Erfolgsfaktoren von Pop-up Stores zusammen.

In den letzten Jahren wurde in der Startup-Szene über eine neuartige Form des Onlinehandels debattiert: Abo-Commerce. Hierbei handelt es sich um ein Geschäftsmodell, bei dem Kunden in regelmäßigen Abständen mit einer online bestellten Ware beliefert werden, ohne dafür erneute Bestellungen aufgeben zu müssen (Warkentin 2013, ExperCash GmbH 2015). Bislang findet Abo-Commerce in der deutschen Wissenschaft noch wenig Beachtung. Der vorliegende Beitrag stellt die Ergebnisse einer inhaltsanalytischen Untersuchung zur Abbildung der Abo-Commerce-Landschaft in Deutschland vor. In recent years, a discussion about a novel form of online-based business models has taken place among young entrepreneurs: online home delivery subscriptions. Thereby, online-subscribers can get convenient home delivery on a continuing basis without reordering (Warkentin 2013, ExperCash GmbH 2015). So far, online home delivery subscriptions have not been intensively researched within the academic field in Germany. The paper presents results on a qualitative research project focusing on mapping the landscape of German companies offering such services.

Zusammenfassung: Basierend auf den bekannten versicherungsmathematischen Berechnungsmethoden zur Bestimmung der Höhe von versicherungstechnischen Verbindlichkeiten für die Lebensversicherung wird eine Lösung zur Kalkulation von Marktwerten vorgestellt, welche den Prinzipien von Solvency II Rechnung trägt. Kernstück dabei ist die Diskontierung von wahrscheinlichkeitsgewichteten künftigen Cashflows, welche durch die Berechnung von aktuarischen Barwerten unter Einbeziehung von Rechnungsgrundlagen 2. Ordnung (Zinskurve, Stornoverhalten, Kosten, Prämienfreistellungsverhalten, etc.) umgesetzt wird. Die Studie enthält sowohl die Herleitung und Diskussion des benötigten Formelwerkes als auch die exemplarische Darstellung anhand ausgewählter Tarifbeispiele. Die besprochenen Prinzipien sind auch maßgeblich für die geplanten IFRS Vorschriften, welche mittlerweile als Exposure Draft vorliegen

The present paper studies the probability of ruin of an insurer, if excess of loss reinsurance with reinstatements is applied. In the setting of the classical Cramer-Lundberg risk model, piecewise deterministic Markov processes are used to describe the free surplus process in this more general situation. It is shown that the finite-time ruin probability is both the solution of a partial integro-differential equation and the fixed point of a contractive integral operator. We exploit the latter representation to develop and implement a recursive algorithm for numerical approximation of the ruin probability that involves high-dimensional integration. Furthermore we study the behavior of the finite-time ruin probability under various levels of initial surplus and security loadings and compare the efficiency of the numerical algorithm with the computational alternative of stochastic simulation of the risk process. (C) 2011 Elsevier Inc. All rights reserved.