Kiel University of Applied Sciences

Dickel P., Eckardt G.

Afflerbach A., Rohrandt C., Brändl B., Sönksen M., Hench J., Frank S., Börnigen D., Alawi M., Mynarek M., Winkler B., Ricklefs F., Synowitz M., Dührsen L., Rutkowski S., Wefers A.K., et. al.

Abstract Background Molecular brain tumor diagnosis is usually dependent on tissue biopsies or resections. This can pose several risks associated with anesthesia or neurosurgery, especially for lesions in the brain stem or other difficult-to-reach anatomical sites. Apart from initial diagnosis, tumor progression, recurrence, or the acquisition of novel genetic alterations can only be proven by re-biopsies. Methods We employed Nanopore sequencing on cell-free DNA (cfDNA) from cerebrospinal fluid (CSF) and analyzed copy number variations (CNV) and global DNA methylation using a random forest classifier. We sequenced 129 samples with sufficient DNA. These samples came from 99 patients and encompassed 22 entities. Results were compared to clinical diagnosis and molecular analysis of tumor tissue, if available. Results 110/129 samples were technically successful, and 50 of these contained detectable circulating tumor DNA (ctDNA) by CNV or methylation profiling. ctDNA was detected in samples from patients with progressive disease but also from patients without known residual disease. CNV plots showed diagnostic and prognostic alterations, such as C19MC amplifications in embryonal tumors with multilayered rosettes or Chr.1q gains and Chr.6q losses in posterior fossa group A ependymoma, respectively. Most CNV profiles mirrored the profiles of the respective tumor tissue. DNA methylation allowed exact classification of the tumor in 22/110 cases and led to incorrect classification in 2/110 cases. Only 5/50 samples with detected ctDNA contained tumor cells detectable through microscopy. Conclusions Our results suggest that Nanopore sequencing data of cfDNA from CSF samples may be a promising approach for initial brain tumor diagnostics and an important tool for disease monitoring.

Steinhauer K., Meister T.L., Todt D., Krawczyk A., Paßvogel L., Becker B., Paulmann D., Bischoff B., Pfaender S., Brill F.H., Steinmann E.

Summary The outbreak of the SARS-CoV-2 pandemic is triggering a global health emergency alert. Until vaccination becomes available, a bundle of effective preventive measures is desperately needed. Recent research is indicating the relevance of aerosols in the spread of SARS-CoV-2. Thus, in this study commercially available antiseptic mouthwashes based on the active ingredients chlorhexidine digluconate and octenidine dihydrochloride (OCT) were investigated regarding their efficacy against SARS-CoV-2 using the European Standard 14476. Based on the requirement of EN 14476 in which reduction of at least four decimal logarithms (≥4 log10) of viral titre is requested to state efficacy, the OCT-based formulation was found to be effective within a contact time of only 15 s against SARS-CoV-2. Based on this in-vitro data the OCT mouthwash thus constitutes an interesting candidate for future clinical studies to prove its effectiveness in a potential prevention of SARS-CoV-2 transmission by aerosols.

Niemann C.C., Mai R., Dickel P.

• Organizational and individual-level drivers of employee engagement in corporate entrepreneurial projects were investigated. • Engagement was split into willingness to participate and willingness to lead corporate entrepreneurial projects. • Individual-level intrapreneurial orientation moderates the effects of organizational drivers on the willingness to participate in corporate entrepreneurial projects. • The willingness to lead corporate entrepreneurial projects is found to be driven by intrapreneurial orientation only. Corporate entrepreneurship has become a fundamental strategy for securing firms’ survival in rapidly changing environments. Despite broad theoretical consensus on the role of organizational drivers (top management support, rewards, work discretion, time availability) for employee engagement in corporate entrepreneurship, empirical studies provided ambiguous results, which might derive from not accounting for individual factors. Based on person-organization fit theory, this study analyses the interplay of organizational drivers and individual-level intrapreneurial orientation on (a) employee willingness to participate and (b) their willingness to lead corporate entrepreneurial projects. Our experimental study demonstrates that organizational drivers foster the willingness to participate in such projects, especially when individuals exhibit a strong intrapreneurial orientation. Regarding the willingness to lead corporate entrepreneurial projects, intrapreneurial orientation is the central factor, while organizational drivers are less effective. In short, our findings support that individual intrapreneurial orientation (nature), and not organizational drivers (nurture) alone, are key to fostering corporate entrepreneurship.

Gardashov R., Eminov M., Kara G., Emecen Kara E.G., Mammadov T., Huseynova X.

It is well known, that for the efficient usage of solar energy the choosing the optimal location and direction of solar panels is one of most important issues. Finding the correct solution for this problem is especially significant in mountain regions that have a complex topography. A new method for the determination of the optimal daily panel direction is presented. The method is based on a simple mathematical model of solar radiation, which determines the amount of solar energy for any instant of time and any point taking into account shadowing of the Sun caused by surrounding relief. The optimal direction of the solar panel is determined analytically, as a solution of the derived system of equations. An algorithm for the determination of daily, monthly, seasonal and annual optimal directions is realised. The results of calculations and measurements for the chosen site are presented and the adequacy of the method is tested. The method can be especially useful for the smart determination of optimal direction and installation of panels in mountain regions which have high touristic potential and require clean energy usage.

Magouh N., Dietze M., Bakhti H., Solterbeck C., Azrar L., Es-Souni M.

• The dielectric constant of 0–3 ceramic-polymer composites is very well predicted by finite element analysis (FEA) • FEA is a powerful tool to simulate the pyroelectric properties of the composites. • The through-thickness distribution of the pyroelectric coefficient can be accurately calculated. • FEA allows the component-resolved spatial distribution of the pyroelectric response to be simulated. Dielectric and pyroelectric thick film materials are of growing interest for applications in medicine, advanced sensors, energy storage and energy harvesting. In the present work, thick 0–3 composite films consisting of particles of a relaxor material embedded in the ferroelectric co-polymer PVDF-TrFE are characterized in terms of dielectric and pyroelectric properties. The experimentally measured properties are compared with the predictions of analytical models and finite element analysis (FEA). A three-dimensional numerical model has been developed via FEA to calculate the effective dielectric constant as a function of the volume fraction (0–30%) of the ceramic particles. An electro-thermal coupled model is proposed to calculate the pyroelectric coefficient. Furthermore, the distribution of the pyroelectric coefficient in different layers of the ferroelectric composite with 30 % ceramic volume fraction together with the component-resolved spatial distribution of the pyroelectric response are analyzed. Overall, simulation and experiment results show very good agreement. In particular, by analyzing the temperature distribution in the thick film, it is demonstrated that the pyroelectric coefficient increases from top to bottom surfaces. Ceramic particle distribution also affects the pyroelectric current.

Steinhauer K., Meister T.L., Todt D., Krawczyk A., Paßvogel L., Becker B., Paulmann D., Bischoff B., Eggers M., Pfaender S., Brill F.H., Steinmann E.

Summary In the ongoing SARS CoV-2 pandemic, effective disinfection measures are needed, and guidance based on the methodological framework of the European Committee for Standardization (CEN) may enable the choice of effective disinfectants on an immediate basis. This study aimed to elucidate whether disinfectants claiming ‘virucidal activity against enveloped viruses' as specified in the European Standard EN 14476 as well as in the German Association for the Control of Viral Diseases/Robert Koch Institute (DVV/RKI) guideline are effectively inactivating SARS-CoV-2. Two commercially available formulations for surface disinfection and one formulation for hand disinfection were studied regarding their virucidal activity. Based on the data of this study the enveloped SARS-CoV-2 is at least equally susceptible compared to the standard test virus vaccinia used in the EN 14476 and DVV/RKI guidelines. Thus, chemical disinfectants claiming ‘virucidal activity against enveloped viruses' based on the EN 14476 and DVV/RKI guidelines will be an effective choice to target enveloped SARS-CoV-2 as a preventive measure.

Dickel P., Sienknecht M., Hörisch J.

Understanding the antecedents of social entrepreneurship is critical for unleashing the potential of social entrepreneurship and thus for tackling social problems. While research has provided valuable insights into imprinting of the conventional entrepreneur, research on differences between social and conventional entrepreneurship suggests that social entrepreneurs evolve differently. Using survey data of 148 social entrepreneurs, we draw on the concepts of imprinting and critical incident recognition as a framework for understanding how social entrepreneur’s childhood experiences and parental exposure to social entrepreneurship affect social entrepreneurial activity in adulthood. First, our results suggest that social entrepreneurs are imprinted by their childhood experiences but not by parental exposure to social entrepreneurship. Second, imprints tend to persist over time when they are linked to critical incidents regarding social entrepreneurship. These insights contribute to a deeper understanding of imprinting mechanisms in social entrepreneurship contexts and highlight the importance of making examples of social entrepreneurship tangible to children.

Mai R., Dickel P.

Schnack J., Bruckner S., Suncksen H., Schumann U., Mallwitz R.

An increasing demand of electronic components suitable for high-speed switching in automotive applications has driven the development of high-frequency dc-link capacitors. Aluminum (Al)-electrolytic capacitors symbolize a promising, high-energy-density capacitor technology suitable for low-cost high-voltage automotive applications. However, the parasitic elements still represent a technological barrier of Al-electrolytic capacitors. In order to develop a novel capacitor, this article aims to develop guidelines for Al-electrolytic capacitors with reduced parasitic elements. This article concludes with the introduction of an automotive inverter concept, which benefits from the developed capacitors.