Temperature dependent electron-hole recombination in polymer light-emitting diodes

The current density–voltage characteristics of poly(dialkoxy p-phenylene vinylene) based polymer are investigated as a function of temperature. Model calculations show that the differences between single and double carrier devices can be well understood by taking into account a bimolecular recombination process. It is found that the bimolecular recombination is thermally activated with an identical activation energy as measured for the charge carrier mobility. This demonstrates that the recombination process is of the Langevin type, and explains why the conversion efficiency (photon/carrier) of a polymer light-emitting diode is temperature independent

Enrichment and characterization of dendritic cells from human bronchoalveolar lavages

In the present study about 0.3% to 1.6% of human bronchoalveolar lavage (BAL) cells were identified as typical dendritic cells (DC), having an irregular outline, lobulated nucleus, and clear distinguishable acid phosphatase activity or EBM11 (anti-CD68) reactivity in a spot near the nucleus. After DC enrichment, using transient adherence to plastic, FcR-panning, and a density metrizamide gradient, a population containing 7-8% typical DC was obtained. This DC-enriched low density fraction, containing the highest percentages of DC, very strongly induced T cell proliferation in an allogeneic mixed leucocyte reaction (MLR), which was significantly higher than that induced by other partly (un)fractionated BAL cells. These data indicate that DC seem to be the major accessory cells in the BAL fluid, and therefore may be important in the regulation of T cell immune responses in the lung

Effects on an employee volunteering program on the work force: the ABN-Amro case

One of the new ways used by companies to demonstrate their social responsibility is to encourage employee volunteering, whereby employees engage in socially beneficial activities on company time, while being paid by the company. The reasoning is that it is good for employee motivation (internal effects) and good for the company reputation (external effects). This article reports an empirical investigation of the internal effects of employee volunteering conducted amongst employees of the Dutch ABN-AMRO bank. The study showed that (a) socio-demographic characteristics from employee volunteers markedly differ from those of non-volunteers and community volunteers and (b) employee volunteering seems to have positive effects on attitudes and behavior towards the organization. © Springer 2005

De waarde van ambulante 24-uursslokdarmmanometrie bij de diagnostiek van retrosternale pijn van niet-cardiale origine

The clinical relevance of a system of ambulatory 24-hour oesophageal pressure and pH recording with automated data analysis was investigated in 33 unselected patients with non-cardiac chest pain. After conventional manometry with edrophonium (Tensilon) provocation, 24-hour oesophageal pH and pressure monitoring was performed. In 17 patients conventional manometry, edrophonium provocation and 24-hour pH recording revealed an oesophageal origin of the symptoms: 6 patients had oesophageal motility disorders, 3 were positive responders to edrophonium and 8 had chest pain associated with gastro-oesophageal reflux. In none of the patients who had a pain attack during prolonged oesophageal pressure recording, was a new motility disorder detecte

Physiological gastroesophageal reflux and esophageal motor activity studied with a new system for 24-hour recording and automated analysis

Gastroesophageal reflux and esophageal motility were studied for 24 hr in 32 ambulatory healthy volunteers (20-73 years old), using a newly developed system, consisting of a microprocessor-based data recorder and algorithms for fully automated data analysis. Physiological reflux was more extensive than expected on the basis of widely used normal values. The percentage of time with pH less than 4 and the duration of the reflux episodes increased with age. Of the more than 2000 esophageal contractions occurring per day, peristaltic contractions constituted 50.9 +/- 2.0%. Their amplitude was significantly lower between meals than during meals and during the night. The duration of the peristaltic contractions increased with age. Simultaneous contractions constituted 10.4 +/- 1.2% of the esophageal contractions. Their incidence increased with age. We conclude that continuous ambulatory 24-hr recording with automated analysis of esophageal motility and pH profile is feasible, that the upper limits of normal in ambulatory esophageal pH recording are higher than previously accepted, and that age, meals, and body position must be taken into account in the interpretation of both 24-hr esophageal pH and pressure dat

Microcomputer-based system for 24-hour recording of oesophageal motility and pH profile with automated analysis

A system developed for long-term simultaneous recording of oesophageal motility and pH in the ambulant patient is described. The system consists of a microprocessor based data-acquisition and preprocessing device, a personal computer for postprocessing, report generation and data storage, a miniature two-sensor pressure catheter and a pH electrode. Identification and classification of oesophageal contractions are performed in separate steps, using online preprocessing software for identification and offline postprocessing software for categorisation, classification and report generation. Contractions are categorised as peristaltic, simultaneous or nontransmitte and classified according to their amplitude, duration and propagation velocity. The method described reduces the amount of data from 870 kbyte to approximately 40 kbyte per 24 hours in a multiparameter recording device, and offers the opportunity for offline postprocessing with different sets of criteria. The system has been found to be accurate and reliable in 24-hour studies in both healthy volunteers and patients with non-cardiac chest pai