Hochschule Hannover
  • Hannover, Niedersachsen, Germany
Recent publications
Recent research efforts have highlighted the potential of hybrid composites in the context of additive manufacturing. The use of hybrid composites can lead to an enhanced adaptability of the mechanical properties to the specific loading case. Furthermore, the hybridization of multiple fiber materials can result in positive hybrid effects such as increased stiffness or strength. In contrast to the literature, where only the interply and intrayarn approach has been experimentally validated, this study presents a new intraply approach, which is experimentally and numerically investigated. Three different types of tensile specimens were tested. The non-hybrid tensile specimens were reinforced with contour-based fiber strands of carbon and glass. In addition, hybrid tensile specimens were manufactured using an intraply approach with alternating carbon and glass fiber strands in a layer plane. In addition to experimental testing, a finite element model was developed to better understand the failure modes of the hybrid and non-hybrid specimens. The failure was estimated using the Hashin and Tsai–Wu failure criteria. The specimens showed similar strengths but greatly different stiffnesses based on the experimental results. The hybrid specimens demonstrated a significant positive hybrid effect in terms of stiffness. Using FEA, the failure load and fracture locations of the specimens were determined with good accuracy. Microstructural investigations of the fracture surfaces showed notable evidence of delamination between the different fiber strands of the hybrid specimens. In addition to delamination, strong debonding was particularly evident in all specimen types.
Fulfilment is a key driver for the digitalisation of the grocery sector and thus a major source of value creation. Although value creation is contingent on a multiplicity of contextual factors, extant research has mainly explored fulfilment in the generic realms of e-commerce and does not provide empirically grounded insights into the collective interplay of fulfilment attributes. Because e-grocery features unique exigencies and trade-offs that require non-generic theorisation, a functional and cross-domain perspective is required to comprehend the role of fulfilment in creating value in this sector. Following a multi-method approach, this paper combines a literature review with an empirical investigation of 111 e-grocers to produce three main outcomes. First, a conceptually-grounded and empirically-refined taxonomy to capture important decision attributes of e-grocery fulfilment. Second, six archetypes to indicate common combinations of these attributes. Third, a contingency model to disclose value relationships between attributes and outcome performance. Our results contribute to the body of knowledge on e-grocery value creation as well as the explanatory understanding of operational configurations and digital transformation conditions in this industry.
718 Background: Predictive markers for immune checkpoint inhibition (ICI) in renal cell carcinoma patients are still missing. Until now, mainly primary tumor tissues have been analyzed to identify reliable markers including PD-L1, although distant metastases represent the therapy targets. Taking into account putative heterogeneity between primary tumors and metastases as well as dynamic changes during tumor progression and treatment, markers from liquid biopsies seem to be more suitable. The aim of this study was to investigate the predictive value of PD-L1 in plasma and on extracellular vesicles (EV) from plasma in the Nivoswitch trial. Methods: Plasma samples at randomization were obtained from 39 patients who received 3 months of tyrosine kinase inhibitor (TKI) therapy followed by random allocation to Nivolumab (“switch arm”) or continued TKI therapy (control arm) and during treatment (day 30). PD-L1 concentration was quantified by ELISA. EVs were isolated by ultracentrifugation or by using a commercial kit. They were characterized by Western blotting using cell specific, EV-specific markers as well as PD-L1 antibody. The data was analyzed by Mann Whitney and Kruskal Wallis tests as well as Kaplan Meier estimates. Results: PD-L1 was detected in plasma and EVs in all patients. PD-L1 plasma concentration was similar between response categories both in the overall cohort and the control (TKI) arm. In contrast, PD-L1 concentration in the “switch arm” was significantly lower in patients with objective response compared to patients with stable (p=0.028) or progressive disease (p=0.008) at day 0, whereas no significant difference occurred at day 30. Plasma PD-L1 levels during treatment (day 30 compared to day 0) did not show an association with therapy response in both arms. A trend towards better OS was found in patients with lower PD-L1 irrespective of treatment arm, but not for PFS. PD-L1 was detected on plasma EVs both by Western blotting as well as by ELISA, although the concentrations were too low for statistical analysis. Conclusions: In this study, plasma PD-L1 concentration did not show strong associations with clinical outcomes which might be caused by the rather small sample size and inherent heterogeneity of treatment. However, PD-L1 concentrations may have prognostic value confirming published data on tumor tissues. PD-L1 is detectable on EVs from plasma. Further studies should investigate the potential of EVs as biomarkers as well as their functional role in therapy response, especially in ICI. Clinical trial information: NCT02959554 .
628 Background: Standard treatment for 1st-line mRCC are IO-combinations. Data from real-world collectives are rare. In this multicenter study, we therefore evaluated safety and effectiveness of cabozantinib/nivolumab in Germany. Methods: Data were collected retrospectively from eight GU cancer centres in Germany. Patients (pts) with advanced or metastatic renal cell carcinoma (mRCC) were eligible. Treatment with cabozantinib 40 mg orally + nivolumab 240 or 480 mg i.v. was mandatory and administered according to routine care. Adverse events (AEs) were reported according to CTCAE 5.0. Objective response rate per RECIST 1.1 and Progression Free Survival (PFS) were calculated from start of treatment to progression or death. Descriptive statistics and KM-plots were utilized, where appropriate. Results: 67 suitable pts (62.7% male) with median age of 67.6 years were included. The most common histology was clear cell RCC (ccRCC) in 67.2% (n=45). Nephrectomy was performed in 56.7% (n=38). ECOG 0-1 was 76.1% (n=51). IMDC scores were: 0 in 11 (16.4%), ≥ 1 in 45 (67.1%), missing in 11 pts (16.4%). 29.9% (n=20) required dose reductions or interruptions. Partial response was documented in 46.3% (n=31), stable disease in 32.8% (n=22), and progressive disease in 4.5% (n=3) as best overall response. Data were missing in 14.9% (n=10). Median Follow-up was 8.3 mo, median treatment duration was 6.0 months, PFS rate at 6 month was 81.9% overall (79.3% for ccRCC; 85.9% for non-ccRCC). AEs (all grades) were reported in 82.1% (n=55) and 47.8% (n=32) for grade 3-5. Elevated liver enzymes (40.3%), diarrhea (22.4%) and hand-foot-syndrome (20.9%) were the 3 most frequent AEs of any grade and causality. Conclusions: In this real-world cohort of mRCC pts. cabozantinib + nivolumab was shown to be safe and feasible. While no new safety signals were reported, a reduced dose was frequently utilized. Our data support the use of cabozantinib + nivolumab as a first-line standard. Major limitations were the retrospective data capture and short follow-up of our study.
Coaxial laser wire directed energy deposition promises a direction-independent buildup of near net shape geometries and surface coatings. Simultaneously introducing two different wire materials into the processing zone enables the production of in situ alloyed or even functionally graded structures. Functionally graded materials and in situ alloyed parts aim to extend the range of materials for development purposes. This work covers the intermixing behavior of two wire materials with greatly differing element contents. Therefore, a multiple diode coaxial laser (DiCoLas) processing head is used consisting of three individually controllable fiber coupled laser diodes with a combined maximum output power of 660 W and a wavelength of 970 nm. Two metal wires, 1.4430 and 1.4718, with a diameter of 0.8 mm are provided simultaneously to the processing zone under an incidence angle of 3.5° to the processing head's middle axis. The DiCoLas processing head enables a stable welding process with good dimensional accuracy of the single welding geometries. Single weld seams and multiple-layer structures are investigated to cover the intermixing behavior for different applications of additive manufacturing. Thermal images of the melting process provide an insight into the melting behavior of the two wire materials and the formation of the weld seam. energy-dispersive x-ray-mappings and line scans display the element distribution of the main alloying elements along the seam cross section. Furthermore, hardness measurements examine the hardness progression along the multiple-layer welding structures showing an even progression of the hardness values over the entire cross section.
We report velocity-dependent internal energy distributions of nitric oxide molecules, NO, scattered off graphene supported on gold to further explore the dynamics of the collision process between NO radicals and graphene. These experiments were performed by directing a molecular beam of NO onto graphene in a surface-velocity map imaging setup, which allowed us to record internal energy distributions of the NO radicals as a function of their velocity. We do not observe bond formation but (1) major contributions from direct inelastic scattering and (2) a smaller trapping-desorption component where some physisorbed NO molecules have residence times on the order of microseconds. This is in agreement with our classical molecular dynamics simulations which also observe a small proportion of two- and multi-bounce collisions events but likewise a small proportion of NO radicals trapped at the surface for the entire length of the molecular dynamics simulations (a few picoseconds). Despite a collision energy of 0.31 eV, which would be sufficient to populate NO(v = 1), we do not detect vibrationally excited nitric oxide.
Background: The eResearch system "Prospective Monitoring and Management App (PIA)" allows researchers to implement questionnaires on any topic and to manage biosamples. Currently, we use PIA in the longitudinal study ZIFCO (Integrated DZIF Infection Cohort within the German National Cohort) in Hannover (Germany) to investigate e.g. associations of risk factors and infectious diseases. Our aim was to assess user acceptance and compliance to determine suitability of PIA for epidemiological research on transient infectious diseases. Methods: ZIFCO participants used PIA to answer weekly questionnaires on health status and report spontaneous onset of symptoms. In case of symptoms of a respiratory infection, the app requested participants to self-sample a nasal swab for viral analysis. To assess user acceptance, we implemented the System Usability Scale (SUS) and fitted a linear regression model on the resulting score. For investigation of compliance with submitting the weekly health questionnaires, we used a logistic regression model with binomial response. Results: We analyzed data of 313 participants (median age 52.5 years, 52.4% women). An average SUS of 72.0 reveals good acceptance of PIA. Participants with a higher technology readiness score at the beginning of study participation also reported higher user acceptance. Overall compliance with submitting the weekly health questionnaires showed a median of 55.7%. Being female, of younger age and being enrolled for a longer time decreased the odds to respond. However, women over 60 had a higher chance to respond than women under 60, while men under 40 had the highest chance to respond. Compliance with nasal swab self-sampling was 77.2%. Discussion: Our findings show that PIA is suitable for the use in epidemiologic studies with regular short questionnaires. Still, we will focus on user engagement and gamification for the further development of PIA to help incentivize regular and long-term participation.
The present article shifts the focus and burden of whistleblowing away from an individual to the collective and argues for the necessary incorporation of whistleblowing into an ethical infrastructure in institutions of higher education. The authors argue that institutions of higher learning should be understood as collective agents bestowed with ethical responsibility which obliges them to act in an ethical manner. The fundamental principle guiding the ethical practice of all higher-learning institutions should be a culture of voice because conscientization – the purpose of education – necessitates dialogue to emerge. However, this culture of voice is not self-evident in institutions of higher learning and transpires in the harmful ways in which some of these institutions react to the disclosure of their problematic practices by whistleblowers. In light of this, the authors propose that one should not expect individuals to assume a whistleblower role; it is the higher-education institution’s ethical responsibility to create an infrastructure which integrates channels for critical engagement with problematic practices and supports a culture of voice. This infrastructure should consist of four fundamental elements: whistleblowing’s enablement, whistleblowers’ protection, the correction of problematic practices, and the recognition of the whistleblower’s action.
Die gesetzlich vorgesehene Bereitstellung von Digitalisierungsangeboten stellt öffentliche Verwaltungen vor steigende Herausforderungen. Aufgrund der Hete-rogenität der Nutzerinnen und Nutzer ist es für öffentliche Verwaltungen häufig problematisch, klare Anforderungen zu erheben und zu erfüllen. Hinzukommen strukturelle und organisatorische Gegebenheiten wie beispielsweise ausgeprägte Entscheidungshierarchien, die eine nutzerzentrierte Vorgehensweise erschweren können. Darüber hinaus sieht sich die öffentliche Verwaltung zunehmend mit komplexer werdenden Problemen konfrontiert. Es stellt sich daher die Frage, wie in der öffentlichen Verwaltung ein moderner Ansatz zur Nutzerzentrierung und Problemlösung eingesetzt werden kann. Dieser Artikel präsentiert die Ergebnisse einer Einzelfallstudie bei der Niedersächsischen Landesbehörde für Straßenbau und Verkehr (NLStBV). Wir haben mit einer Fokusgruppe einen Design-Thinking-Workshop durchgeführt, um Potenziale und Anwendungsmöglichkeiten des Ansatzes in der öffentlichen Verwaltung zu identifizieren. Auf Basis einer SWOT-Analyse haben wir die Ergebnisse untersucht und geben vier konkrete Handlungs-empfehlungen für die Einführung sowie Nutzung von Design Thinking.
Zusammenfassung Der Beitrag beschreibt die aktuellen Überlegungen zur Weiterentwicklung der informationswissenschaftlichen Studiengänge der Hochschule Hannover vor dem Hintergrund des laufenden Prozesses der Reakkreditierung. Zentrale Aspekte bilden hierbei die inhaltliche und strukturelle Weiterentwicklung des Curriculums vor dem Hintergrund der sich verändernden Bedürfnisse der Bibliotheken. Ebenfalls berücksichtigt werden verschiedene Formen der Kooperation mit der Bibliothekspraxis, hochschuldidaktische Überlegungen sowie die Einbindung der Studiengänge in die informationswissenschaftliche Forschungslandschaft.
To adjust the surface properties of ceramics, a broad spectrum of functionalization strategies is available. Due to the chemical inertness, activation of the starting material is required as a first step. Subsequently, wet chemical derivatization techniques by silanes, phosphonates, and carboxylates are available, which can generate a specific surface chemical functionality and control properties like hydrophobicity and many more. This chapter gives an overview of the most common and successful surface functionalization methods for ceramics. A special focus is on surface decoration with organic and biomolecular entities used in applications in biotechnology and environmental technology. The advantages and disadvantages of each functionalization approach with a focus on operability of the method, the obtained loading capacities, as well as the effect on the material properties are discussed in detail. Particular attention will be given to functionalization approaches for ceramic particles and assemblies thereof, 2D‐planar surfaces, and 3D‐components to improve their performance for biotechnological and environmental applications.
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1,767 members
Dnyanesh Limaye
  • Faculty of Information and Communication
Oliver Johannes Bott
  • Fakultät III - Medien, Information und Design (Faculty III - Media, Information and Design)
Felix Koltermann
  • Faculty of Information and Communication
Andreas Eickhorst
  • Diakonie_Gesundheit und Soziales
Volker Ahlers
  • Faculty IV, Dept. of Computer Science
Ricklinger Stadtweg 120, 30451, Hannover, Niedersachsen, Germany
Head of institution
Josef von Helden
+49 511-9296-0
+49 511-9296-1010