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The electrolyte is an essential constituent of the light-emitting electrochemical cell (LEC), since its operating mechanism is dependent on the redistribution of mobile ions in the active layer. Recent developments of new ion transporters have yielded high-performance devices, but knowledge about the interactions between the ionic species and the ion transporters and the influence of these interactions on the LEC performance is lacking. We therefore present a combined computational and experimental effort that demonstrates that the selection of the end group in a star-branched oligomeric ion transporter based on trimethylolpropane ethoxylate has a paramount influence on the ionic interactions in the electrolyte and thereby also on the performance of the corresponding LECs. With hydroxyl end groups, the cation from the salt is strongly coordinated to the ion transporter, which leads to suppression of ion pairing, but the penalty is a hindered ion release and a slow turn-on for the LEC devices. With methoxy end groups, an intermediate coordination strength is seen together with the formation of contact ion pairs, but the LEC performance is very good with fast turn-on. Using a series of ion transporters with alkyl carbonate end groups, the ion transporter:cation coordination strength is lowered further, but the turn-on kinetics are slower than what is seen for devices comprising the methoxy end-capped ion transporter.

The light-emitting electrochemical cell (LEC) exhibits capacity for efficient charge injection from two air-stable electrodes into a single-layer active material, which is commonly interpreted as implying that the LEC operation is independent of the electrode selection. Here, we demonstrate that this is far from the truth and that the electrode selection instead has a strong influence on the LEC performance. We systematically investigate 13 different materials for the positive anode and negative cathode in a common LEC configuration with the conjugated polymer Super Yellow as the electroactive emitter and find that Ca, Mn, Ag, Al, Cu, indium tin oxide (ITO), and Au function as the LEC cathode, whereas ITO and Ni can operate as the LEC anode. Importantly, we demonstrate that the electrochemical stability of the electrode is paramount and that particularly electrochemical oxidation of the anode can prohibit the functional LEC operation. We finally report that it appears preferable to design the device so that the heights of the injection barriers at the two electrode/active material interfaces are balanced in order to mitigate electrode-induced quenching of the light emission. As such, this study has expanded the set of air-stable electrode materials available for functional LEC operation and also established a procedure for the evaluation and design of future efficient electrode materials.

The next generation of emissive devices should preferably be efficient, low-cost, and environmentally sustainable, and as such utilize all electrically generated excitons (both singlets and triplets) for the light emission, while being free from rare metals such as iridium. Here, we report on a step toward this vision through the design, fabrication, and operation of a host–guest light-emitting electrochemical cell (LEC) featuring an organic thermally activated delayed fluorescence (TADF) guest that harvests both singlet and triplet excitons for the emission. The rare-metal-free active material also consists of a polymeric electrolyte and a polymeric compatibilizer for the facilitation of a cost-efficient and scalable solution-based fabrication, and for the use of air-stable electrodes. We report that such TADF-LEC devices can deliver uniform green light emission with a maximum luminance of 228 cd m–2when driven by a constant-current density of 770 A m–2, and 760 cd m–2during a voltage ramp, which represents a one-order-of-magnitude improvement in comparison to previous TADF-emitting LECs.

Eight patients with liver metastases from endocrine gastrointestinal tumours were examined with magnetic resonance imaging of the liver before and during treatment with interferon. T1, T2 and tumour size were measured and compared with tumour marker levels and symptomatic improvement or deterioration. Before therapy all tumours showed a long T1 and T2, in comparison to normal liver and fat, and during therapy they all showed a decrease in T1. As no change in liver T1 and fat T1 occurred, the decreased tumour T1 is considered to be a therapy effect. This cannot be fully explained but is possibly due to a reduction in tumour growth rate during interferon treatment. There was no certain correlation between tumour T1 and tumour marker levels or symptomatic changes.

Dual wavelength microfluorometry was utilized to measure the cytoplasmic calcium concentration (Cai2+) of single parathyroid cells loaded with the indicator fura-2. The method enabled the first registrations of Cai2+ of normal human parathyroid cells, available only in minute numbers. At 0.5 mM extracellular Ca2+, the Cai2+ levels were similar in normal human and bovine cells. Both cell types responded with an initial Cai2+ transient followed by a sustained increase when raising extracellular Ca2+ to 3.0 mM. The sustained effect exhibited a sigmoidal relation to extracellular Ca2+ in the 0.5–3.0 mM range. Although the increase was somewhat greater in the human cells, the half maximal responses were obtained at almost identical extracellular Ca2+ concentrations. Whereas K+ depolarization decreased Cai2+, the Cai2+ channel blocker D-600 had dual actions, raising Cai2+at 0.5 mM Ca2+ and decreasing it at 3.0 mM Cai2+, and the effects were similar in the bovine and human cells. The present experimental approach verified the validity of utilizing bovine cells as controls in studies of human parathyroid tissue and it appears suitable for analysis of the role of different subpopulations of parathyroid cells in the abnormal parathyroid tissue of patients with hyperparathyroidism.

Eight patients with liver metastases from endocrine gastrointestinal tumours were examined with magnetic resonance imaging of the liver before and during treatment with interferon. T1, T2 and tumour size were measured and compared with tumour marker levels and symptomatic improvement or deterioration. Before therapy all tumours showed a long T1 and T2, in comparison to normal liver and fat, and during therapy they all showed a decrease in T1. As no change in liver T1 and fat T1 occurred, the decreased tumour T1 is considered to be a therapy effect. This cannot be fully explained but is possibly due to a reduction in tumour growth rate during interferon treatment. There was no certain correlation between tumour T1 and tumour marker levels or symptomatic changes.

The influence of chronic and acute exposure to parathyroid hormone (PTH) on formation and breakdown of type I collagen, using two recently developed radioimmunoassays for serum PICP (the carboxyterminal propeptide of type I procollagen) and serum ICTP (the carboxyterminal telopeptide of type I collagen), have been evaluated. Fasting morning values were obtained from 18 women with primary hyperparathyroidism (HPT) and an equal number of age-matched, healthy controls. A 24-hour infusion of synthetic human parathyroid hormone (PTH 1-38) was performed in 14 healthy females. The patients with HPT had higher values for serum ICTP than the controls (6.0±3.0 and 4.1±2.1 μg/liter; P<0.05), whereas the serum PICP concentrations were not different (170±72 and 151±65 μg/liter; n.s.). During infusion of PTH in healthy subjects, there was an increase of the serum ICTP concentrations (from 3.6±1.3 to 4.4±1.8 μg/liter; P<0.001) whereas those of serum PICP decreased (from 185±78 to 118±42 μg/liter; P≤0.0001). The increase of serum ICTP during infusion of PTH was positively related to the increase of serum calcium and other indices of bone resorption, i.e., fasting urinary excretions of hydroxyproline and calcium. The decrease of serum PICP was also related to the changes of serum ICTP and hydroxyproline in urine, serum calcium, and alkaline phosphatase but not to osteocalcin, an established marker of osteoblastic activity. The findings support the fact that serum ICTP is a valuable method for evaluating bone resorption and is also easy to perform. Furthermore, the discordant results for the different markers of osteoblastic activity indicat that they reflect different functions of the cell.

Dual wavelength microfluorometry was utilized to measure the cytoplasmic calcium concentration (Cai2+) of single parathyroid cells loaded with the indicator fura-2. The method enabled the first registrations of Cai2+ of normal human parathyroid cells, available only in minute numbers. At 0.5 mM extracellular Ca2+, the Cai2+ levels were similar in normal human and bovine cells. Both cell types responded with an initial Cai2+ transient followed by a sustained increase when raising extracellular Ca2+ to 3.0 mM. The sustained effect exhibited a sigmoidal relation to extracellular Ca2+ in the 0.5–3.0 mM range. Although the increase was somewhat greater in the human cells, the half maximal responses were obtained at almost identical extracellular Ca2+ concentrations. Whereas K+ depolarization decreased Cai2+, the Cai2+ channel blocker D-600 had dual actions, raising Cai2+at 0.5 mM Ca2+ and decreasing it at 3.0 mM Cai2+, and the effects were similar in the bovine and human cells. The present experimental approach verified the validity of utilizing bovine cells as controls in studies of human parathyroid tissue and it appears suitable for analysis of the role of different subpopulations of parathyroid cells in the abnormal parathyroid tissue of patients with hyperparathyroidism.

Relaxation times and relative proton densities were calculated from magnetic resonance examinations of the liver in eight patients with liver metastases from neuroendocrine tumours. Single, spinm—echo sequences with eight different repetition times and a four-echo sequence were used to calculate T1, and T2in tumour and normal liver, and the proton density tumour-liver quotient, before and during treatment with interferon. Changes over time of these parameters were compared with variations in tumour marker levels and changes in size and number of the metastases. During therapy, six out of eight cases showed a decrease in tumour T1, five responding to therapy and one with stationary disease, while the two patients with progressive disease showed unchanged tumour T1. The proton density quotient also decreased in a corresponding way, indicating a change in water content in tumours responding to interferon therapy. No significant change in liver T1, tumour T2or liver T2occurred in any patient. It is thus possible to perform reliable measurements of relaxation parameters over time, which may be valuable in follow-up of tumour treatment.