University of Groningen

About: University of Groningen is a education organization based out in Groningen, Groningen, Netherlands. It is known for research contribution in the topics: Population & Poison control. The organization has 36346 authors who have published 69116 publications receiving 2940370 citations. The organization is also known as: Rijksuniversiteit Groningen & RUG.

Effect of Temperature and Illumination on the Electrical Characteristics of Polymer-Fullerene Bulk-Heterojunction Solar Cells

Abstract: The current-voltage characteristics of ITO/PEDOT:PSS/OC1C10-PPV:PCBM/Al solar cells were measured in the temperature range 125-320 K under variable illumination, between 0.03 and 100 mW cm(-2) (white light), with the aim of determining the efficiency-limiting mechanism(s) in these devices, and the temperature and/or illumination range(s) in which these devices demonstrate optimal performance. (ITO: indium tin oxide; PEDOT:PSS: poly(styrene sulfonate)-doped poly(ethylene dioxythiophene); OC1C10-PPV: poly[2-methoxy-5-(3,7-dimethyl octyloxy)-1,4-phenylene vinylene]; PCBM: phenyl-C-61 butyric acid methyl ester.) The short-circuit current density and the fill factor grow monotonically with temperature until 320 K. This is indicative of a thermally activated transport of photogenerated charge carriers, influenced by recombination with shallow traps. A gradual increase of the open-circuit voltage to 0.91 V was observed upon cooling the devices down to 125 K. This fits the picture in which the open-circuit voltage is not limited by the work-function difference of electrode materials used. The overall effect of temperature on solar-cell parameters results in a positive temperature coefficient of the power conversion efficiency, which is 1.9% at T = 320 K and 100 mW cm(-2) (2.5% at 0.7 mW cm(-2)). The almost-linear variation of the short-circuit current density with light intensity confirms that the internal recombination losses are predominantly of monomolecular type under short-circuit conditions. We present evidence that the efficiency of this type of solar cell is limited by a light-dependent shunt resistance. Furthermore, the electronic transport properties of the absorber materials, e.g., low effective charge-carrier mobility with a strong temperature dependence, limit the photogenerated current due to a high series resistance, therefore the active layer thickness must be kept low, which results in low absorption for this particular composite absorber.

Procalcitonin to initiate or discontinue antibiotics in acute respiratory tract infections

Abstract: Unnecessary antibiotic use significantly contributes to increasing bacterial resistance, medical costs and the risk of drug-related adverse events. The blood marker procalcitonin increases in bacterial infections and decreases when patients recover from the infection. Hence, procalcitonin may be used to support clinical decision making for the initiation and discontinuation of antibiotic therapy in patients with a clinical suspicion of infection. Randomised controlled trials have demonstrated that such a strategy works, particularly in patients with an infection of the respiratory tract. However, most of these individual studies did not include enough patients to allow for a conclusive assessment about safety (low statistical power). Thus, the risk for mortality and severe complications associated with procalcitonin-guided decision making remained unclear. This systematic review included individual patient data from 14 randomised controlled trials with a total of 4211 participants. When looking at these combined data, we found no increased risk for all-cause mortality or treatment failure when procalcitonin was used to guide initiation and duration of antibiotic treatment in participants with acute respiratory infections compared to control participants. However, we found a consistent reduction of antibiotic use, mainly due to lower prescription rates in primary care and lower duration of antibiotic courses in emergency department and intensive care unit patients. This analysis is limited to adult patients with respiratory infections excluding patients who were immuno-compromised (i.e. HIV positive, those receiving immuno-suppressive therapies or chemotherapy). Most trials were conducted in Europe and China and similar studies in other countries including the United States are warranted.

The Determinants of Quality of Life of Nursing Home Residents with Young-Onset Dementia and the Differences between Dementia Subtypes.

Abstract: Aims: The aims of this study are to (1) explore the determinants of quality of life (QoL) in nursing home residents with young-onset dementia (YOD), (2) investigate whether there are differences between dementia subtypes (Alzheimer dementia, vascular/mixed dementia, frontotemporal dementia, other) regarding these determinants, and (3) compare QoL profiles of YOD nursing home residents across dementia subtypes. Methods: This cross-sectional study included 207 nursing home residents. Multilevel modeling was used to determine the relationships between QoL and neuropsychiatric symptoms (NPS), dementia severity, psychotropic drug use (PDU), dementia subtype, age, and gender. Additional multilevel models were used to compare aspects of QoL between dementia subtypes. Results: Residents' QoL was negatively associated with advanced dementia, PDU, and NPS. In general, the relationships between the determinants and QoL were similar across the dementia subtypes. Aspects of QoL differed by dementia subtype. Residents with frontotemporal dementia showed less negative emotions, accepted more help and experienced better quality of relationships with professional caregivers, had a more positive self-image, felt more comfortable in the nursing home environment, and experienced lower quality of social relationships. Conclusions: Considering the high rates of NPS and PDU in YOD residents and their negative associations with QoL, we recommend emphasizing services to manage and reduce NPS and PDU in nursing home residents with YOD. Furthermore, our findings suggest accounting for differences in aspects of QoL by dementia subtype to address specific needs and thereby improve QoL.