Towards a multidimensional healthy ageing phenotype

Purpose of review: There is great interest in developing tools to measure healthy ageing and to identify early stages of health impairment, which may guide the implementation of interventions to prevent or delay the development of disease, disability, and mortality. Here, we review the most recent developments directed to operationalize, and test, definitions of healthy ageing. Recent findings: There is lack of consensus about how to define healthy ageing and, unsurprisingly, diversity in the instruments for its measurement. However, progress is being made in describing and in devising tools to capture the healthy ageing phenotype. Attempts to measure healthy ageing have relied primarily on cross-sectional data collected in older people. More recent studies have assessed the healthy ageing phenotype using markers of multiple functional domains and have used longitudinal data to model the dynamics and trajectories of healthy ageing. Summary: Given the complexity of the ageing process, no single measure is able to predict the ageing trajectory. Current attempts to operationalize the healthy ageing phenotype have relied on markers and data from earlier cohort studies and are limited by the tools used to collect data in those studies. Such data are often unsuitable to detect early subtle declines in function and/or are inappropriate for use in younger old adults. Future studies employing more objective and novel markers of healthy ageing are likely to offer opportunities to define and operationalize the healthy ageing phenotype

High mannose-specific lectin Msl mediates key interactions of the vaginal Lactobacillus plantarum isolate CMPG5300

To characterize the interaction potential of the human vaginal isolate Lactobacillus plantarum CMPG5300, its genome was mined for genes encoding lectin-like proteins. cmpg5300.05_29 was identified as the gene encoding a putative mannose-binding lectin. Phenotypic analysis of a gene knock-out mutant of cmpg5300.05_29 showed that expression of this gene is important for auto-aggregation, adhesion to the vaginal epithelial cells, biofilm formation and binding to mannosylated glycans. Purification of the predicted lectin domain of Cmpg5300.05_29 and characterization of its sugar binding capacity confirmed the specificity of the lectin for high-mannose glycans. Therefore, we renamed Cmpg5300.05_29 as a mannose-specific lectin (Msl). The purified lectin domain of Msl could efficiently bind to HIV-1 glycoprotein gp120 and Candida albicans, and showed an inhibitory activity against biofilm formation of uropathogenic Escherichia coli, Staphylococcus aureus and Salmonella Typhimurium. Thus, using a combination of molecular lectin characterization and functional assays, we could show that lectin-sugar interactions play a key role in host and pathogen interactions of a prototype isolate of the vaginal Lactobacillus microbiota

Origin of multiple memory states in organic ferroelectric field-effect transistors

In this work, we investigate the ferroelectric polarization state in metal-ferroelectric-semiconductor-metal structures and in ferroelectric field-effect transistors (FeFET). Poly(vinylidene fluoride-trifluoroethylene) and pentacene was used as the ferroelectric and semiconductor, respectively. This material combination in a bottom gate—top contact transistor architecture exhibits three reprogrammable memory states by applying appropriate gate voltages. Scanning Kelvin probe microscopy in conjunction with standard electrical characterization techniques reveals the state of the ferroelectric polarization in the three memory states as well as the device operation of the FeFET

Low-temperature and low-voltage, solution-processed metal oxide n-TFTs and flexible circuitry on large-area polyimide foil

In this article, we report on high-performance solution-based n-type metal oxide TFTs processed directly on polyimide foil and annealed at 250 °C. Saturation mobilities exceeding 2 cm²/(Vs) and Ion/Ioff ratios beyond 108 have been achieved. Using these oxide n-TFTs, fast and low-voltage flexible circuitry is presented. Furthermore, a complete 8-bit RFID transponder chip, containing 294 oxide n-TFTs has been fabricated. Both high-speed and low-voltage operation makes the presented oxide n-TFT technology suited for both the pixel driving and embedded line-drive circuitry at the borders of flexible AMOLED displays

A Recurrent Mutation in KCNA2 as a Novel Cause of Hereditary Spastic Paraplegia and Ataxia

The hereditary spastic paraplegias (HSPs) are heterogeneous neurodegenerative disorders with over 50 known causative genes. We identified a recurrent mutation in KCNA2 (c.881G>A, p.R294H), encoding the voltage-gated K+-channel, K(V)1.2, in two unrelated families with HSP, intellectual disability (ID), and ataxia. Follow-up analysis of >2,000 patients with various neurological phenotypes identified a de novo p.R294H mutation in a proband with ataxia and ID. Two-electrode voltage-clamp recordings of Xenopus laevis oocytes expressing mutant KV1.2 channels showed loss of function with a dominant-negative effect. Our findings highlight the phenotypic spectrum of a recurrent KCNA2 mutation, implicating ion channel dysfunction as a novel HSP disease mechanism.Peer reviewe

Device Architecture and Materials for Organic Light-Emitting Devices: Targeting High Current Densities and Control of the Triplet Concentration /

Device Architecture and Materials for Organic Light-Emitting Devices focuses on the design of new device and material concepts for organic light-emitting devices, thereby targeting high current densities and an improved control of the triplet concentration. A new light-emitting device architecture, the OLED with field-effect electron transport, is demonstrated. This device is a hybrid between a diode and a field-effect transistor. Compared to conventional OLEDs, the metallic cathode is displaced by one to several micrometers from the light-emitting zone, reducing optical absorption losses. The electrons injected by the cathode accumulate at an organic heterojunction and are transported to the light-emission zone by field-effect. High mobilities for charge carriers are achieved in this way, enabling a high current density and a reduced number of charge carriers in the device. Pulsed excitation experiments show that pulses down to 1 µs can be applied to this structure without affecting the light intensity, suggesting that pulsed excitation might be useful to reduce the accumulation of triplets in the device. The combination of all these properties makes the OLED with field-effect electron transport particularly interesting for waveguide devices and future electrically pumped lasers. In addition, triplet-emitter doped organic materials, as well as the use of triplet scavengers in conjugated polymers are investigated

Device Architecture and Materials for Organic Light-Emitting Devices: Targeting High Current Densities and Control of the Triplet Concentration (Architectuur en materialen voor organische licht-emitterende structuren)

This thesis focuses on the design of new device and material concepts for organic light-emitting devices, thereby targeting high current densities and an improved control of the triplet concentration. A new light-emitting device architecture, the OLED with field-effect electron transport, is demonstrated. This device is a hybrid between a diode and a field-effect transistor. Compared to conventional OLEDs, the metallic cathode is displaced by one to several micrometers from the light-emitting zone, reducing optical absorption losses. The electrons injected by the cathode accumulate at an organic heterojunction and are transported to the light-emission zone by field-effect. High mobilities for charge carriers are achieved in this way, enabling a high current density and a reduced number of charge carriers in the device. Pulsed excitation experiments show that pulses up to 1 µs can be applied to this structure without affecting the light intensity, suggesting that pulsed excitation might be useful to reduce the accumulation of triplets in the device. The combination of all these properties make the OLED with field-effect electron transport particularly interesting for waveguide devices and future electrically pumped lasers. In addition, triplet-emitter doped organic materials as well as the use of triplet scavengers in conjugated polymers are investigated.status: publishe

Triplet dynamics and charge carrier trapping in triplet-emitter doped conjugated polymers

Phosphorescent (Ph) properties and charge carrier trapping have been studied in conjugated polymer CNPPP with incorporated red-emitting Btp(2)Ir(acac) metal-organic complex by time-resolved photoluminescence and thermally-stimulated luminescence (TSL) techniques. We characterized intrinsic Ph of CNPPP matrix and dynamics of triplet excitations of Btp(2)Ir(acac) confined by the polymer host. Combined studies of time and intensity dependence of guest Ph have demonstrated that the observed decrease in the Ph efficiency in CNPPP:Btp(2)Ir(acac) system at increasing excitation intensity is dominated by mutual host-guest triplet-triplet annihilation. We observed Ph spectral diffusion effects at 10 wt.% of Btp(2)Ir(acac) dispersed in a polymer matrix, which is a proof for the triplet excitons migration though the manifold of triplet-emitter sites, and which governs the Ph concentration quenching effect. TSL measurements have provided direct evidence that the triplet-emitter molecules create a deep charge trap in the conjugated polymer and allowed trap characterization. (c) 2009 Elsevier B.V. All rights reserved.status: publishe