Wireless communication fields and non-specific symptoms of ill health: a literature review

Zusammenfassung: Dieser Artikel aktualisiert eine frühere systematische Literaturübersicht (1) zu den Auswirkungen hochfrequenter elektromagnetischer Felder (RF-EMF) auf die gesundheitsbezogene Lebensqualität. Zwischen August 2007 und November 2010 sind zur Exposition gegenüber Nahfeldquellen wie Mobil- und Schnurlostelefonen neun randomisierte experimentelle Studien und zwei beobachtende Studien erschienen. Die Fernfeldexposition, wie sie beispielsweise in der Umgebung von Mobilfunkbasisstationen auftritt, wurde in sechs experimentellen und acht beobachtenden Studien untersucht. Die meisten Experimente zeigten keinen Zusammenhang zwischen der Hochfrequenzbelastung und dem Auftreten von unspezifischen Symptomen wie Kopfschmerzen, Schwindel oder Konzentrationsstörungen. Die sporadisch beobachteten Assoziationen ergaben kein einheitliches Muster, weder bezüglich der Symptomform noch bezüglich der Effektrichtung (Zu- oder Abnahme). Auch in den beobachtenden Studien bestanden grösstenteils keine Zusammenhänge zwischen der RF-EMF-Belastung und dem Auftreten von Beschwerden. Die Aussagekraft dieser Studien wird allerdings dadurch eingeschränkt, dass die Expositionskontraste in den Kollektiven gering waren und Fehler in der Expositionsabschätzung nicht ausgeschlossen werden können. Ausserdem fehlen Studien über einen längeren Beobachtungszeitraum, und es gibt noch kaum Untersuchungen an Kindern und Jugendlichen. Insgesamt weisen die aktuellen Studien nicht auf einen Zusammenhang zwischen der alltäglichen Hochfrequenzbelastung und dem Auftreten von unspezifischen Symptomen hin. Sie zeigen auch nicht, dass Personen, die sich selbst als hypersensibel bezeichnen, empfindlicher auf RF-EMF reagieren als der Rest der Bevölkerung. Da sich die Technik der Mobilkommunikation rasch weiter entwickelt und die alltägliche Exposition in Zukunft voraussichtlich ansteigen wird, sind aber longitudinale Studien zur Untersuchung eventueller Langzeiteffekte erforderlich. Wegen der weiten Verbreitung der drahtlosen Kommunikationstechnik hätten schädliche Auswirkungen eine grosse Public Health-Relevan

Parental stress in paediatric day-case surgery

Day-case surgery involves a considerable amount of stress not only for the children who undergo surgery but also for their parents. In a prospective survey analysis performed in 1995/1996, we identified the following main factors influencing the amount of stress experienced by parents: feelings of insufficient preparation and problems with postoperative pain at home. As a consequence, measures were taken regarding information and pain management, including the creation of an interactive CD-ROM. We then analysed the consequences of our interventions regarding parental stress. In this study we collected the data of all patients who underwent day-case surgery during two additional 13-month periods in 1997/1998 and 1999/2000. The methods of data collection remained unchanged for all three periods and included a questionnaire for the parents. In total, 1,490 questionnaires were analysed. Comparing the three time periods, parents' feelings of being well-informed improved significantly (91% vs. 98% vs. 97%, P<0.0001). However, the percentage of those experiencing moderate to severe stress did not change substantially (16% vs. 9% vs. 19%, not significant). Analgaesics were given more frequently over the years in a general as well as a prophylactic manner (20% vs. 35% vs. 43%, P<0.0001). Nevertheless, problems with pain control at home remained unchanged (33% vs. 23% vs. 29%, not significant). Despite considerable efforts to improve information, parental stress did not significantly decrease. It cannot be assessed yet whether wrong information was given or whether a certain degree of stress cannot be prevented. There is some evidence that improvements in coping with pain-related problems might be a promising next ste

Microsoft Academic is on the verge of becoming a bibliometric superpower

Last year, the new Microsoft Academic service was launched. Sven E. Hug and Martin P. Brändle look at how it compares with more established competitors such as Google Scholar, Scopus, and Web of Science. While there are reservations about the availability of instructions for novice users, Microsoft Academic has impressive semantic search functionality, broad coverage, structured and rich metadata, and solid citation analysis features. Moreover, accessing raw data is relatively cheap. Given these benefits and its fast pace of development, Microsoft Academic is on the verge of becoming a bibliometric superpower

Robust Convergence of Power Flow using Tx Stepping Method with Equivalent Circuit Formulation

Robust solving of critical large power flow cases (with 50k or greater buses) forms the backbone of planning and operation of any large connected power grid. At present, reliable convergence with applications of existing power flow tools to large power systems is contingent upon a good initial guess for the system state. To enable robust convergence for large scale systems starting with an arbitrary initial guess, we extend our equivalent circuit formulation for power flow analysis to include a novel continuation method based on transmission line (Tx) stepping. While various continuation methods have been proposed for use with the traditional PQV power flow formulation, these methods have either failed to completely solve the problem or have resulted in convergence to a low voltage solution. The proposed Tx Stepping method in this paper demonstrates robust convergence to the high voltage solution from an arbitrary initial guess. Example systems, including 75k+ bus test cases representing different loading and operating conditions for Eastern Interconnection of the U.S. power grid, are solved from arbitrary initial guesses.Interconnection of the U.S. power grid, are solved from arbitrary initial guesses

Magnetic field exposure and neurodegenerative diseases - recent epidemiological studies

Summary.: Objectives: To analyse the results of recent studies not yet included in a 2003 report of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) on occupational exposure to low-frequency electromagnetic fields as potential risk factor for neurodegenerative diseases. Methods: A literature search was conducted in the online databases of PubMed, ISI Web of Knowledge, DIMDI and COCHRANE, as well as in specialised databases and journals. Eight studies published between January 2000 and July 2005 were included in the review. Results: The fi ndings of these studies contribute to the evidence of an association between occupational magnetic field exposure and the risk of dementia. Regarding amyotrophic lateral sclerosis, the recent results confirm earlier observations of an association with electric and electronic work and welding. Its relationship with magnetic field exposure remains unsolved. There are only few findings pointing towards an association between magnetic field exposure and Parkinson's disease. Conclusions: The epidemiological evidence for an association between occupational exposure to low-frequency electromagnetic fields and the risk of dementia has increased during the last five years. The impact of potential confounders should be evaluated in further studie

A nonmitochondrial hydrogen production in Naegleria gruberi

Naegleria gruberi is a free-living heterotrophic aerobic amoeba well known for its ability to transform from an amoeba to a flagellate form. The genome of N. gruberi has been recently published, and in silico predictions demonstrated that Naegleria has the capacity for both aerobic respiration and anaerobic biochemistry to produce molecular hydrogen in its mitochondria. This finding was considered to have fundamental implications on the evolution of mitochondrial metabolism and of the last eukaryotic common ancestor. However, no actual experimental data have been shown to support this hypothesis. For this reason, we have decided to investigate the anaerobic metabolism of the mitochondrion of N. gruberi. Using in vivo biochemical assays, we have demonstrated that N. gruberi has indeed a functional [FeFe]-hydrogenase, an enzyme that is attributed to anaerobic organisms. Surprisingly, in contrast to the published predictions, we have demonstrated that hydrogenase is localized exclusively in the cytosol, while no hydrogenase activity was associated with mitochondria of the organism. In addition, cytosolic localization displayed for HydE, a marker component of hydrogenase maturases. Naegleria gruberi, an obligate aerobic organism and one of the earliest eukaryotes, is producing hydrogen, a function that raises questions on the purpose of this pathway for the lifestyle of the organism and potentially on the evolution of eukaryotes

Senescence in vitro and ionising radiations—the human diploid fibroblast model

The influence of ionising radiations on ageing is still controversial. Since Hayflick established the concept that diploid cells have finite lifespan in vitro, human diploid fibroblast (HDF) cultures have been recognised as a potent experimental model for cytogerontological investigations. In this study HDF cultures in phase II were exposed to acute irradiation with either X-rays on fast neutrons. The replicative potentials and labelling indices with [3H]thymidine were measured post irradiation until the cultures ceased growth in phase III. Cell mortality was measured by cloning. The apparent loss in replicative potential of irradiated mass cultures was wholly attributable to the loss of viable clonogenic cells. The current concept of precocious clonal senescence in vitro as a late effect of irradiation in clonogenic survivors is not supported by the present experiments. Instead, our results suggest that exposure to a single dose of ionising radiations either causes total replicative incapacitation (killing) of HDF cells and their progeny early after irradiation or leaves their replicative potentials unperturbed

How cost-effective is public R&D in stimulating firm innovation?

This paper assesses the impact of public R&D on firm R&D using patent application data on the county and firm level in Germany. We address the endogeneity of public R&D by employing an instrumental variable estimator that uses lagged institutional funding for research institutes and universities as excluded instruments. We find that one additional public patent application generates 3.5 firm patent applications in the median county, but also that the relationship turns negative for high levels of public R&D. We estimate the public costs per firm patent to be between 0.8 and 1.5 million EURO

Combined Treatment Strategies for Microtubule Stabilizing Agent-Resistant Tumors

Background: Resistance to microtubule-stabilizing agents is a major hurdle for successful cancer therapy. We investigated combined treatment of microtubule-stabilizing agents (MSAs) with inhibitors of angiogenesis to overcome MSA resistance. Methods: Treatment regimens of clinically relevant MSAs (patupilone and paclitaxel) and antiangiogenic agents (everolimus and bevacizumab) were investigated in genetically defined MSA-resistant lung (A549EpoB40) and colon adenocarcinoma (SW480) tumor xenografts in nude mice (CD1-Foxn1, ICRnu; 5-14 per group). Tumor growth delays were calculated by Kaplan-Meier analysis with Holm-Sidak tests. All statistical tests were two-sided. Results: Inhibition of mTOR-kinase by everolimus only minimally reduced the proliferative activity of β tubulin-mutated lung adenocarcinoma cells alone and in combination with the MSA patupilone, but everolimus inhibited expression and secretion of vascular endothelial growth factor (VEGF) from these cells. mTOR-kinase inhibition strongly sensitized tumor xenografts derived from these otherwise MSA-resistant tumor cells to patupilone. Tumors treated with the combined modality of everolimus and patupilone had statistically significantly reduced tumor volume and stronger tumor growth delay (16.2±1.01 days) than control- (7.7±0.3 days, P = .004), patupilone- (10±0.97 days, P = .009), and everolimus-treated (10.6±1.4 days, P = .014) tumors. A combined treatment modality with bevacizumab also resensitized this MSA-refractory tumor model to patupilone. Treatment combination also strongly reduced microvessel density, corroborating the relevance of VEGF targeting for the known antivasculature-directed potency of MSA alone in MSA-sensitive tumor models. Resensitization to MSAs was also probed in P glycoprotein-overexpressing SW480-derived tumor xenografts. Different bevacizumab regimens also sensitized this otherwise-resistant tumor model to clinically relevant MSA paclitaxel. Conclusions: A treatment combination of MSAs with antiangiogenic agents is potent to overcome tumor cell-linked MSA resistance and should be considered as strategy for MSA-refractory tumor entitie