Umweltfreundliche Materialien und dehnbare Substrate für gedruckte elektrochemische Displays

Die wachsenden Märkte der tragbaren Elektronik (engl. Wearables) und des Internet-der-Dinge (engl. Internet-of-Things, IoT), welchen die organische Elektronik neue Möglichkeiten hinsichtlich des Gewichts, der Flexibilität und abgestimmten Materialeigenschaften bietet, erfordern für deren Anwendungen einfach herzustellende, kostengünstige, tragbare und personalisierbare Displays, um Informationen mit dem Anwender zu teilen. Für eine erfolgreiche Markteinführung solcher Displays eignen sich aufgrund der Anforderungen insbesondere digitale Drucktechnologien, wie der Tintenstrahldruck. Allerdings ist es absehbar, dass diese Displays aufgrund der geringen Lebensdauer (bspw. medizinische Hygienevorschriften, Verpackungen) und des hohen Verbrauchs zur Menge des Elektroschrotts und dessen Umweltauswirkungen beitragen werden. Daher wird in dieser Arbeit die Verwendung von umweltfreundlichen und bioabbaubaren Materialien in elektrochromen (EC) und elektrochemilumineszenten (ECL) Bauteilen untersucht, um mittels Tintenstrahldruck personalisierte bioabbaubare reflektive Displays und umweltfreundliche Dual-Mode-Displays zu entwickeln. Diese umfassen natürliche Salze und Farbstoffe, bioabbaubare Polymere, umweltfreundliche Halbleiter und ionische Flüssigkeiten, sowie grüne Lösemittel. Die umweltfreundlichen bzw. bioabbaubaren funktionellen Schichten der elektrochemischen optoelektronischen Bauteile werden hinsichtlich ionischer Leitfähigkeit, EC Kontrast & Effizienz, sowie Emission optimiert. Die EC Bauteile erreichen dabei Kontraste über 45 %, Kolorationseffizienzen über 237 cm²·C-1 und Schaltzeiten bis zu unter einer Sekunde. Auf der Grundlage der optimierten EC-Bauteile werden in einem weiteren Schritt im Tintenstrahldruckverfahren bioabbaubare tragbare Displays entwickelt. Diese Displays bestehen aus 33 individuell ansteuerbaren Einzelsegmenten und haben einen Bioabbaubarkeitstest von unabhängiger Seite gemäß ISO14855 bestanden. Die vorgestellten ECL-Bauteile weisen eine maximale Leuchtdichte von 108 mcd·m-² bei 5 V und 40 Hz auf und ermöglichen durch die Kombination mit den EC Bauteilen die Entwicklung umweltfreundlicher gedruckter Dual-Mode-Displays. Aufgrund der Bauteilarchitektur der Dual-Mode-Displays aus einer Kombination von EC und ECL Schichten können Informationen in Form von statischen Bildern in einem reflektiven und einem emissiven Modus angezeigt werden, welche über Schalten zwischen Wechsel- und Gleichspannung reversibel gewechselt werden können. Da zudem zukünftige Anwendungen im Bereich der Wearables und IoT mechanischer Spannung ausgesetzt sein werden, müssen elektrische Bauteile mit einer ausreichenden Dehnbarkeit entwickelt werden. Als Lösungsansatz, der einen Transfer etablierter Druckprozesse von flexiblen auf dehnbare Substrate ermöglicht, wird in dieser Arbeit eine dehnbare Plattform, aus festen Inseln, die über Brücken verbunden sind, vorgestellt. Dazu werden dehnbare und flexible Substrate über eine Silankopplung verbunden, um Inseln und Brücken zu formen. Es wird gezeigt, dass auf den Inseln und Brücken mittels Tintenstrahldruck aufgebrachte Elektroden und Bauteile vor mechanischer Belastung geschützt sind. Daher konnte das vorgestellte bioabbaubare, reflektive Display auf die dehnbaren Insel-Brücken-Plattformen übertragen werden. Die Ergebnisse dieser Arbeit heben die Möglichkeiten, die die organische Elektronik für dehnbare und gedruckte Display-Applikationen und zur Reduzierung der Menge des Elektroschrotts durch die Verwendung bioabbaubarer Materialien in elektronischen Bauteilen bereitstellt, hervor. Daher ist die Arbeit ein wichtiger Beitrag zur Entwicklung von im Tintenstrahldruckverfahren hergestellten bioabbaubaren Displays und dehnbarer Elektronik im Hinblick auf eine zukünftige Markteinführung

Stretchable inkjet-printed electronics on mechanically compliant island-bridge architectures covalently bonded to elastomeric substrates

Herein, we present an approach that allows versatile combination of inkjet-printed electronics and stretchable substrates. For this, we created a hybrid platform made out of stretchable Ecoflex covalently bonded via silane monolayers to flexible polyethylene terephthalate islands interconnected by bridges. The islands served as platforms where conductive lines, capacitive sensors and electrochromic devices (ECDs) were fabricated by inkjet printing. The robustness of the approach is highlighted by the minor influence of strain on the conductivity of printed Ag electrodes, which changed the resistance only by 1.3% at an applied strain of 50%. Furthermore, we demonstrated capacitor sensors capable of responding to strain changing their capacitance from 0.2 to 1.6 pF. To further show the applicability of the approach for multilayer/multimaterial optoelectronic elements, we processed ECDs capable of displaying information on the stretchable platform. Thus, we demonstrate how this digital and additive concept can be applied for the scalable integration of printed optoelectronic devices onto stretchable systems without relying on lithographic processes

Biodegradable inkjet-printed electrochromic display for sustainable short-lifecycle electronics

The fabrication of electronics on the basis of biofriendly materials aims to counterbalance the negative trends conveyed by the short life-cycle of electronics. Furthermore, these materials open the possibility to develop optoelectronic technologies which will be in contact with the human body. In this work, we present an electrochromic display fabricated by resource- and energy-efficient digital printing techniques. The biodegradation of the device is certified under the ISO 14855 standard. The display comprises of a poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) electrochromic layer, a gelatin-based electrolyte and Au electrodes deposited on a cellulose di-acetate substrate. We investigate the impact of various naturally sourced ionic species on the ionic conductivity of the electrolyte and the figures of merit of the display. The printed devices show an electrochromic contrast of 32 ± 4% and switching times of 3.0 ± 1.4 s, comparable to the spincoated reference devices. The utilization of inkjet printing enables the fabrication of different device designs with individually addressable pixels. The display can be worn innocuously on the skin without loss of performance thanks to the self-adhesion properties of the gelatin hydrogel. The present work highlights the use of industrial relevant technology for the fabrication of truly ecofriendly optoelectronic systems

Exchange-correlation effects on quantum wires with spin-orbit interactions under the influence of in-plane magnetic fields

12 pages.-- PACS numbers: 73.63.Nm, 71.70.Ej, 71.15.Mb, 71.70.Gm.-- Final full-text version of the paper available at: http://dx.doi.org/10.1103/PhysRevB.76.115306.Within the noncollinear local spin-density approximation, we have studied the ground state structure of a parabolically confined quantum wire submitted to an in-plane magnetic field, including both Rashba and Dresselhaus spin-orbit interactions. We have explored a wide range of linear electronic densities in the weak (strong) coupling regimes that appear when the ratio of spin-orbit to confining energy is small (large). These results are used to obtain the conductance of the wire. In the strong coupling limit, the interplay between the applied magnetic field irrespective of the in-plane direction, the exchange-correlation energy, and the spin-orbit energy produces anomalous plateaus in the conductance vs linear density plots that are otherwise absent, or washes out plateaus that appear when the exchange-correlation energy is not taken into account.This work has been performed under Grants No. FIS2005-01414 and No. FIS2005-02796 from DGI (Spain), Grant No. 2005SGR00343 from Generalitat de Catalunya, and under Grant No. INFN07-30 from the Italian INFN-Spanish DGI agreement.http://dx.doi.org/10.1103/PhysRevB.76.11530

Color‐Selective Printed Organic Photodiodes for Filterless Multichannel Visible Light Communication

Future lightweight, flexible, and wearable electronics will employ visible-lightcommunication schemes to interact within indoor environments. Organic photodiodes are particularly well suited for such technologies as they enable chemically tailored optoelectronic performance and fabrication by printing techniques on thin and flexible substrates. However, previous methods have failed to address versatile functionality regarding wavelength selectivity without increasing fabrication complexity. This work introduces a general solution for printing wavelength-selective bulk-heterojunction photodetectors through engineering of the ink formulation. Nonfullerene acceptors are incorporated in a transparent polymer donor matrix to narrow and tune the response in the visible range without optical filters or light-management techniques. This approach effectively decouples the optical response from the viscoelastic ink properties, simplifying process development. A thorough morphological and spectroscopic investigation finds excellent charge-carrier dynamics enabling state-of-the-art responsivities >10² mA W⁻¹ and cutoff frequencies >1.5 MHz. Finally, the color selectivity and high performance are demonstrated in a filterless visible-light-communication system capable of demultiplexing intermixed optical signals

TP53 codon 72 polymorphism in susceptibility, overall survival, and adjuvant therapy response of gliomas

TP53 is a key tumor suppressor gene that encodes a transcriptional factor involved in several cellular mechanisms, including growth arrest, DNA repair, and induction of apoptosis. In addition to TP53 gene mutations, a common polymorphism, Arg72Pro, has been involved in the carcinogenesis process. The Pro72 variant has been associated with a slower induction of apoptosis and may influence the risk of cancer development. The role of Arg72Pro polymorphism in glioma susceptibility is poorly characterized. With the objective of analyzing the role of the TP53 Arg72Pro polymorphism in glioma risk, overall survival, and patient therapy response in a Portuguese population, we conducted a retrospective caseecontrol study, including 171 patients with gliomas and 526 cancer- free individuals. The Arg72Pro genotype was assessed by the polymerase chain reactione restriction fragment length polymorphism technique. No statistically significant differences were observed in the genotypic and allelic frequencies between glioma and control groups, and no statistically significant differences were observed with stratification of gliomas into distinct histological subtypes: astrocytic (n 5 115), glioblastoma (n 5 75), and oligodendroglial (n 5 54) tumors. No significant association was observed between TP53 Arg72Pro and patient overall survival, but KaplaneMeier analysis of glioma patients harboring the Pro72 allele showed a significantly longer survival with adjuvant therapy. In this first assessment of the role of TP53 Arg72Pro polymorphism in a large series of Portuguese glioma tumors, no association was observed with glioma susceptibility or overall survival, except for patients submitted to adjuvant therapy

A high-risk gut microbiota configuration associates with fatal hyperinflammatory immune and metabolic responses to SARS-CoV-2.

Protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and associated clinical sequelae requires well-coordinated metabolic and immune responses that limit viral spread and promote recovery of damaged systems. However, the role of the gut microbiota in regulating these responses has not been thoroughly investigated. In order to identify mechanisms underpinning microbiota interactions with host immune and metabolic systems that influence coronavirus disease 2019 (COVID-19) outcomes, we performed a multi-omics analysis on hospitalized COVID-19 patients and compared those with the most severe outcome (i.e. death, n = 41) to those with severe non-fatal disease (n = 89), or mild/moderate disease (n = 42), that recovered. A distinct subset of 8 cytokines (e.g. TSLP) and 140 metabolites (e.g. quinolinate) in sera identified those with a fatal outcome to infection. In addition, elevated levels of multiple pathobionts and lower levels of protective or anti-inflammatory microbes were observed in the fecal microbiome of those with the poorest clinical outcomes. Weighted gene correlation network analysis (WGCNA) identified modules that associated severity-associated cytokines with tryptophan metabolism, coagulation-linked fibrinopeptides, and bile acids with multiple pathobionts, such as Enterococcus. In contrast, less severe clinical outcomes are associated with clusters of anti-inflammatory microbes such as Bifidobacterium or Ruminococcus, short chain fatty acids (SCFAs) and IL-17A. Our study uncovered distinct mechanistic modules that link host and microbiome processes with fatal outcomes to SARS-CoV-2 infection. These features may be useful to identify at risk individuals, but also highlight a role for the microbiome in modifying hyperinflammatory responses to SARS-CoV-2 and other infectious agents

Utilization of mechanical power and associations with clinical outcomes in brain injured patients: a secondary analysis of the extubation strategies in neuro-intensive care unit patients and associations with outcome (ENIO) trial

Background: There is insufficient evidence to guide ventilatory targets in acute brain injury (ABI). Recent studies have shown associations between mechanical power (MP) and mortality in critical care populations. We aimed to describe MP in ventilated patients with ABI, and evaluate associations between MP and clinical outcomes. Methods: In this preplanned, secondary analysis of a prospective, multi-center, observational cohort study (ENIO, NCT03400904), we included adult patients with ABI (Glasgow Coma Scale ≤ 12 before intubation) who required mechanical ventilation (MV) ≥ 24 h. Using multivariable log binomial regressions, we separately assessed associations between MP on hospital day (HD)1, HD3, HD7 and clinical outcomes: hospital mortality, need for reintubation, tracheostomy placement, and development of acute respiratory distress syndrome (ARDS). Results: We included 1217 patients (mean age 51.2 years [SD 18.1], 66% male, mean body mass index [BMI] 26.3 [SD 5.18]) hospitalized at 62 intensive care units in 18 countries. Hospital mortality was 11% (n = 139), 44% (n = 536) were extubated by HD7 of which 20% (107/536) required reintubation, 28% (n = 340) underwent tracheostomy placement, and 9% (n = 114) developed ARDS. The median MP on HD1, HD3, and HD7 was 11.9 J/min [IQR 9.2-15.1], 13 J/min [IQR 10-17], and 14 J/min [IQR 11-20], respectively. MP was overall higher in patients with ARDS, especially those with higher ARDS severity. After controlling for same-day pressure of arterial oxygen/fraction of inspired oxygen (P/F ratio), BMI, and neurological severity, MP at HD1, HD3, and HD7 was independently associated with hospital mortality, reintubation and tracheostomy placement. The adjusted relative risk (aRR) was greater at higher MP, and strongest for: mortality on HD1 (compared to the HD1 median MP 11.9 J/min, aRR at 17 J/min was 1.22, 95% CI 1.14-1.30) and HD3 (1.38, 95% CI 1.23-1.53), reintubation on HD1 (1.64; 95% CI 1.57-1.72), and tracheostomy on HD7 (1.53; 95%CI 1.18-1.99). MP was associated with the development of moderate-severe ARDS on HD1 (2.07; 95% CI 1.56-2.78) and HD3 (1.76; 95% CI 1.41-2.22). Conclusions: Exposure to high MP during the first week of MV is associated with poor clinical outcomes in ABI, independent of P/F ratio and neurological severity. Potential benefits of optimizing ventilator settings to limit MP warrant further investigation