7 research outputs found
Enhanced Lifetime of Cyanine Salts in Dilute Matrix Luminescent Solar Concentrators via Counterion Tuning
Organic
luminophores offer great potential for energy harvesting
and light emission due to tunable spectral properties, strong luminescence,
high solubility, and excellent wavelength selectivity. To realize
their full potential, the lifetimes of luminophores must extend to
many years under illumination. Many organic luminophores, however,
have a tendency to degrade and undergo rapid photobleaching, leading
to the perception of intrinsic instability of organic molecules. In
this work, we demonstrate that by exchanging the counterion of a heptamethine
cyanine salt the photostability and corresponding lifetime of dilute
cyanine salts can be enhanced by orders of magnitude from 10 h to
an extrapolated lifetime of greater than 65,000 h under illumination.
To help correlate and comprehend the underlying mechanism behind this
phenomenon, the water contact angle and binding energy of each pairing
were measured and calculated. We find that increased water contact
angle, and therefore increasing hydrophobicity, generally correlates
to improved lifetimes. Similarly, a lower absolute binding energy
between cation and anion correlates to increased lifetimes. Utilizing
the binding energy formalism, we predict the stability of a new anion
and experimentally verify it with good consistency. Moving forward,
these factors could be used to rapidly screen and identify highly
photostable organic luminophore salt systems for a range of energy
harvesting and light-emitting applications
Enhanced Electroluminescence Efficiency in Metal Halide Nanocluster Based Light Emitting Diodes through Apical Halide Exchange
Metal halide nanoclusters represent
an attractive class of molecular building blocks for the design of
functional materials with superior optical properties that can be
utilized in a range of applications. Here, we demonstrate red and
near-infrared light emitting diodes with a maximum external quantum
efficiency >1%, utilizing phosphorescent octahedral molybdenum
iodide nanoclusters. Efficiency improvement in these devices is realized
by substituting heavier ligands in the apical nanocluster position
that lead to the improvement in photoluminescence and exciton formation
efficiencies in the nanoclusters. These results highlight how modulation
of nanocluster salts with key terminal ligands has a profound effect
on photoluminescence as well as electrical injection
Burden of pulmonary TB and admission diagnosis co-morbidities with HIV, NCDs and CDs.
<p>Data are n TB positive/n tested (%) [95% CI], Odds Ratios (ORs) and associated confidence intervals (CIs) from binary logistic regression analysis.</p>a<p>Multivariate analysis was controlled for the effects of Age and HIV.</p>b<p>Age was analysed as a continuous variable but is displayed as grouped to illustrate the distribution.</p>c<p>Three TB culture negative patients were represented in multiple NCD diagnosis categories.</p>d<p>Two TB culture negative patients were represented in multiple CD diagnosis categories.</p
Study population demographics.
<p>IQR – interquartile range; TB – tuberculosis; PTB – pulmonary TB; EPTB - extrapulmonary TB; CNS – central nervous system.</p>a<p>Pearson chi-squared test.</p>b<p>Admission diagnosis could not be gathered from 14 admissions.</p
TB prevalence in different patient groups stratified by HIV status (HIV status was available for 858/900 study participants).
<p>TB prevalence in different patient groups stratified by HIV status (HIV status was available for 858/900 study participants).</p
Datasheet1_Interobserver variability in target definition for stereotactic arrhythmia radioablation.pdf
BackgroundStereotactic arrhythmia radioablation (STAR) is a potential new therapy for patients with refractory ventricular tachycardia (VT). The arrhythmogenic substrate (target) is synthesized from clinical and electro-anatomical information. This study was designed to evaluate the baseline interobserver variability in target delineation for STAR.MethodsDelineation software designed for research purposes was used. The study was split into three phases. Firstly, electrophysiologists delineated a well-defined structure in three patients (spinal canal). Secondly, observers delineated the VT-target in three patients based on case descriptions. To evaluate baseline performance, a basic workflow approach was used, no advanced techniques were allowed. Thirdly, observers delineated three predefined segments from the 17-segment model. Interobserver variability was evaluated by assessing volumes, variation in distance to the median volume expressed by the root-mean-square of the standard deviation (RMS-SD) over the target volume, and the Dice-coefficient.ResultsTen electrophysiologists completed the study. For the first phase interobserver variability was low as indicated by low variation in distance to the median volume (RMS-SD range: 0.02–0.02 cm) and high Dice-coefficients (mean: 0.97 ± 0.01). In the second phase distance to the median volume was large (RMS-SD range: 0.52–1.02 cm) and the Dice-coefficients low (mean: 0.40 ± 0.15). In the third phase, similar results were observed (RMS-SD range: 0.51–1.55 cm, Dice-coefficient mean: 0.31 ± 0.21).ConclusionsInterobserver variability is high for manual delineation of the VT-target and ventricular segments. This evaluation of the baseline observer variation shows that there is a need for methods and tools to improve variability and allows for future comparison of interventions aiming to reduce observer variation, for STAR but possibly also for catheter ablation.</p