Optimizing the internal electric field distribution of alternating current driven organic light-emitting devices for a reduced operating voltage

This work was funded with financial means of the European Social Fund and the Free State of Saxony through the OrthoPhoto project.The influence of the thickness of the insulating layer and the intrinsic organic layer on the driving voltage of p-i-n based alternating current driven organic light-emitting devices (AC-OLEDs) is investigated. A three-capacitor model is employed to predict the basic behavior of the devices, and good agreement with the experimental values is found. The proposed charge regeneration mechanism based on Zener tunneling is studied in terms of field strength across the intrinsic organic layers. A remarkable consistency between the measured field strength at the onset point of light emission (3-3.1 MV/cm) and the theoretically predicted breakdown field strength of around 3 MV/cm is obtained. The latter value represents the field required for Zener tunneling in wide band gap organic materials according to Fowler-Nordheim theory. AC-OLEDs with optimized thickness of the insulating and intrinsic layers show a reduction in the driving voltage required to reach a luminance of 1000 cd/m2 of up to 23% (8.9 V) and a corresponding 20% increase in luminous efficacy.Publisher PDFPeer reviewe

Neurotoxic and neuroprotective mechanisms of cisplatin-induced polyneuropathies

Auch heute noch spielen Platin-haltige Zytostatika eine wichtige Rolle in der Therapie diverser Krebserkrankungen. Neben ihrer Effektivität in der Behandlung des Tumors führen sie jedoch immer wieder zu schweren Nebenwirkungen. Eine der häufigsten Nebenwirkungen, mit starkem Einfluss auf das Wohlbefinden der Betroffenen, sind schmerzhafte periphere Polyneuropathien. Im Gegensatz zu den Mechanismen der Wirkung von Platin-haltigen Zytostatika auf Tumorzellen, sind die Mechanismen für die Entstehung von Polyneuropathien nicht vollständig verstanden. Einen möglichen Ansatz liefert die bereits in der Literatur beschriebene Störung der intrazellulären Calcium-Homöostase in DRG-Neuronen durch Platin-haltige Zytostatika. Im Rahmen dieser Arbeit sollte der Einfluss von Cisplatin auf die verschiedenen Subtypen von spannungsabhängigen Calciumkanälen (VGCC) mit Hilfe von Patch-Clamp Messungen, immunozytochemischen und immunohistochemischen Färbungen, sowie Verhaltenstestungen untersucht werden. Das Ziel dabei war es, erste Untersuchungen der Calcium-basierten neurotoxischen und neuroprotektiven Mechanismen der Cisplatin-induzierten Polyneuropathien durchzuführen. Durch elektrophysiologische Messungen konnte hierbei gezeigt werden, dass Cisplatin die Subtypen von spannungsabhängigen Calciumkanälen unterschiedlich moduliert. So wurden die Ströme der Calciumkanäle des L-Typs, P-/Q-Typs und T-Typs reduziert, wohingegen eine Proteinkinase C vermittelte Zunahme von N-Typ VGCC beobachtet werden konnte. Durch die Exposition der kultivierten DRG-Neuronen mit Cisplatin konnte eine CaMK II-assoziierte erhöhte Stromdichte von N-Typ VGCC nachgewiesen werden. Diese Erhöhung konnte mit einem erhöhten Proteinlevel dieser Kanäle in Zusammenhang gebracht werden. Auch nach in vivo Cisplatin-Applikation zeigte sich eine signifikante Proteinlevel-Erhöhung der N-Typ VGCC. In Apoptose-Experimenten zeigte sich, dass die durch Cisplatin erhöhte Apoptoserate durch Blockade der N-Typ VGCC mit 1 µM ω-Conotoxin gesenkt werden konnte. Dieses spricht somit für eine Calcium-vermittelte Neurotoxizität von Cisplatin. In Verhaltenstestungen konnte durch die i.v. Gabe von ω-Conotoxin frühe Anzeichen einer Cisplatin-induzierten Polyneuropathie verhindert werden. Durch die in dieser Arbeit durchgeführten Experimente konnte der N-Typ VGCC als wichtiger Faktor für die Genese von schmerzhaften Polyneuropathien nach Cisplatin-Applikationen identifiziert werden. Erstmalig konnte der Einfluss von Cisplatin auf die Subtypen von VGCC beschrieben werden. Durch die Blockade der N-Typ VGCC mit ω-Conotoxin konnte die Induktion einer Polyneuropathie durch Cisplatin in vivo verhindert werden. Dies könnte bereits in naher Zukunft auch in der Therapie bzw. Prävention von Cisplatin-induzierten Polyneuropathien untersucht werden.Platinum-based cytostatic drugs still play an important role in the treatment of cancer. In addition to their high efficacy, they lead to a number of serious side effects. One of the most common side effects with severe impact on the quality of patient´s life is a polyneuropathy, which is a consequence of a neurotoxicity that is focused on dorsal root ganglion neurons with a subsequential axonal damaging. As a key mechanism beside the accumulation of DNA-adducts, which is essential for toxicity in other cell types, disturbances of the calcium-homeostasis by ion channel modulation in dorsal root ganglion (DRG) neurons have been suggested. This study aims on the prevention and clarification of calcium-based mechanisms of neurotoxicity by cisplatin, using a rat model of chemotherapy-induced polyneuropathy with signs of neuropathic pain. Combining in vitro whole-cell patch clamping, immunohisto- and cytochemical staining of DRG and DRG neurons with in vivo behavioural testing the N-type voltage gated calcium channel (VGCC) was identified as the main mediator of calcium influx in DRG neurons after exposure to cisplatin. N-Type VGCC were modulated after cisplatin exposure in function and expression in the DRG. After in vivo and in vitro exposure to cisplatin N-type VGCC currents were significantly increased in massive manner. In addition, immunohistochemical and immunocytochemical staining suggested a significant increase of N-type channels in DRG neurons. For it is known that cisplatin induced neuronal cell death is closely related to activation of caspase-3, the pre-emptive incubation of DRG neurons with ω-conotoxin, a highly specific N-type channel inhibitor before exposure to cisplatin, significantly reduces caspase-3 activation in DRG neurons. As a proof-of concept study rats were treated with a combination of cisplatin with ω-conotoxin to examine a possible neuroprotective effect of with ω-conotoxin against cisplatin induced neuronal cell death. The administration of ω-conotoxin for 12d during a cisplatin administration was able to fully prevent the generation of neuropathic pain in an in vivo trial using a behavioural assessment for >21d. This study provides evidence for a crucial and exclusive role of N-type channels in cisplatin induced neuropathy, which could be prevented by a highly selective ion channel modulator suggesting a neuroprotection. The N-type channel blocker ω-conotoxin is already in common use for the treatment of chronic pain, therefore this data provides evidence for the potential beneficial role of ion channel modulators for neuroprotection and should be easily used for a proof of concept study in a clinical trial

Lihavuuden lääkehoito

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Bibliographic Data Science and the History of the Book (c. 1500–1800)

National bibliographies have been identified as a crucial resource for historical research on the publishing landscape, but using them requires addressing challenges of data quality, completeness, and interpretation. We call this approach bibliographic data science. In this article, we briefly assess the development of book formats and the vernacularization process in early modern Europe. The work undertaken paves the way for more extensive integration of library catalogs to map the history of the book.Peer reviewe

Testing The Limits: A Robustness Analysis Of Logistic Growth Models For Life Cycle Estimation During The COVID-19 Pandemic

The semiconductor industry operates in a dynamic environment characterized by rapid technological advancements, extensive research and development investments, long planning horizons, and cyclical market behavior. Consequently, staying vigilant to technological disruptions and shifting trends is crucial. This is especially challenging when external shocks seriously affect supply chain processes and demand patterns. Particularly, recent events, such as the COVID-19 pandemic, the ongoing Russian invasion of Ukraine, and high consumer price inflation impacting the semiconductor cycle emphasize the need to account for these influences. In this context, we analyze growth patterns and life cycles of various technologies within the semiconductor industry by estimating logistic growth models. The logistic growth model was originally formulated to describe population dynamics. However, many processes outside the discipline of ecology share the fundamental characteristics of natural growth: self-proportionality and a self-regulating mechanism. Out of the different applications, two are of particular interest in the context of strategic business decisions: (1) modeling innovation diffusion and technological change to predict the mid- to long-term growth of a market, and (2) modeling of product life cycles. To obtain market growth and life cycle predictions, we apply the logistic growth model to forecast cumulative revenues by technology over time. This model treats the analyzed technology as a closed system. However, in practice, external shocks are the norm. To analyze the robustness to such external shocks, we compare technology life cycle estimates derived from logistic growth models before and after the effects of COVID-19 became evident for a wide array of semiconductor technologies. We find that the impact of COVID-19 on these life cycle estimates is mixed, but the median change is low. Our findings have implications for the application of logistic growth models in strategic decision-making, helping stakeholders navigate the complexities of technological innovation, diffusion, and market growth

IoT Enabled Environmental Monitoring System

Nowadays, global warming poses a serious threat to our planet. For this reason, the reduction of the gas emitted into the atmosphere is increasingly sought for its purpose. Wireless Sensor Network (WSN) to monitor the concentration of carbon dioxide can therefore be helpful in monitoring air quality. In this research, the integration of wireless sensor networks into IoT is implemented for environmental monitoring. Subsequently, a practical case is described consisting in the implementation of a driver for reading the value of the environmental CO2 concentration, through a sensor with NDIR technology. This paper presents a customized design of an IoT enabled environment monitoring system to monitor CO2 concentrations. Moreover, the performance of low-cost Non-Dispersive Infra-Red (NDIR) was assessed. Thereafter, data related to the operation of the sensor will be graphically reported, as well as a sampling window that is executed to perform the measurement. Finally, possible future developments of the driver will be presented

Alchemy & algorithms : perspectives on the philosophy and history of open science

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