Search

In recent decades, the possibility that use of mobile communicating devices, particularly wireless (mobile and cordless) phones, may increase brain tumour risk, has been a concern, particularly given the considerable increase in their use by young people. MOBI-Kids, a 14-country (Australia, Austria, Canada, France, Germany, Greece, India, Israel, Italy, Japan, Korea, the Netherlands, New Zealand, Spain) case-control study, was conducted to evaluate whether wireless phone use (and particularly resulting exposure to radiofrequency (RF) and extremely low frequency (ELF) electromagnetic fields (EMF)) increases risk of brain tumours in young people. Between 2010 and 2015, the study recruited 899 people with brain tumours aged 10 to 24 years old and 1,910 controls (operated for appendicitis) matched to the cases on date of diagnosis, study region and age. Participation rates were 72% for cases and 54% for controls. The mean ages of cases and controls were 16.5 and 16.6 years, respectively; 57% were males. The vast majority of study participants were wireless phones users, even in the youngest age group, and the study included substantial numbers of long-term (over 10 years) users: 22% overall, 51% in the 20-24-year-olds. Most tumours were of the neuroepithelial type (NBT; n = 671), mainly glioma. The odds ratios (OR) of NBT appeared to decrease with increasing time since start of use of wireless phones, cumulative number of calls and cumulative call time, particularly in the 15-19 years old age group. A decreasing trend in ORs was also observed with increasing estimated cumulative RF specific energy and ELF induced current density at the location of the tumour. Further analyses suggest that the large number of ORs below 1 in this study is unlikely to represent an unknown causal preventive effect of mobile phone exposure: they can be at least partially explained by differential recall by proxies and prodromal symptoms affecting phone use before diagnosis of the cases. We cannot rule out, however, residual confounding from sources we did not measure. Overall, our study provides no evidence of a causal association between wireless phone use and brain tumours in young people. However, the sources of bias summarised above prevent us from ruling out a small increased risk. Funding for the coordination of the MOBI-Kids study was obtained from the European Community's Seventh Framework Programme under grant agreements number 226873 and 603794, and from the Spanish Ministry of Science and Innovation (MINECO). In Spain, additional funding was obtained from the Spanish Health Research Fund (FIS) of the National Institute for Health Carlos III, and from the Junta de Andalucía, Consejería de Salud. Proyecto PI-0317-2010. ISGlobal also acknowledges support from the Spanish Ministry of Science, Innovation and Universities through the “Centro de Excelencia Severo Ochoa 2019-2023” Program (CEX2018-000806-S), support from the Generalitat de Catalunya through the CERCA Program and support from the Secretariat of Universities and Research of the Department of Business and Knowledge of the Generalitat of Catalonia through AGAUR (the Catalan Agency for Management of University and Research Grants) (Project 2017 SGR 1487). Australian participation in MOBI-Kids was supported by the Australian National Health and Medical Research Council with a five-year research grant (grant number: 546130). Austrian participation in MOBI-Kids was partly supported by a grant from the Ministry of Science. In Canada, participation in MOBI-Kids was supported by a university-industry partnership grant from the Canadian Institutes of Health Research (CIHR), reference number 110835, with the Canadian Wireless Telecommunications Association (CWTA) serving as the industrial partner. CWTA provides technical information on wireless telecommunications in Canada and facilitates access to billing records from Canadian network operators, but has no involvement in the design, conduct, analysis, or interpretation of the MOBI-KIDS study. French participation was also supported by the French National Agency for Sanitary Safety of Food, Environment and Labour (ANSES, contract FSRF2008-3), French National Cancer Institute (INCa), Pfizer Foundation and League against cancer. The German study centre received additional funding from the Federal Office for Radiation Protection (BfS) under grant number 3609S30010. In Greece, the study was partially supported by the Hellenic Society for Social Pediatrics and Health Promotion, ELKE (Special Account for Research Grants of the National and Kapodistrian University of Athens) and GGET (General Secretariat for Research and Technology). Mobi-Kids India was supported by Board of Research in Nuclear Sciences (BRNS, sanction no: 2013/38/01-BRNS).

Summary Four parameters were considered in this study to discriminate between tubular adenoma and adenocarcinoma of the colon. The deformation of the tubular profile (TD) and the average sector resultant(AR) were used as supracellular parameters, the vector resultant strain (VS) which represented the cellular crowding as a cellular parameter, and the deformation of the nucleus (ND) as a nuclear parameter. Statistical comparison between the two groups showed that all the parameters had high levels of significance. Direct discriminant analwis was applied to discriminate between the two diseases and all parameters showed large F-ratios; however the evaluation by the stepwise discriminant method indicated that ND had a sufficient power of discrimination between the two diseases. Biplot with confidence interval ellipses (95%) was plotted for ND versus TD to demonstrate the graphical separation of the groups.

Evidence of modulated dissipative structures with an intrinsic wavelength in a nonlinear optical system devoid of Turing instability is given. They are found in the transverse field distribution of an optical cavity containing a liquid crystal light valve. Their existence is related to a transition from flat to modulated fronts connecting the unstable middle branch of a bistability cycle and either of the two stable uniform states. We first analyze the cavity in the limit of nascent bistability, where a modified Swift-Hohenberg equation is derived. This allows for a simple analytical expression of the threshold associated with the transition as well as the wavelength of the emerging structure. Numerical simulations show development of ring-shaped modulated fronts and confirm analytical predictions. We then turn to the full model and find the same transition, both analytically and numerically, proving that this transition in not limited to nascent bistability regimes.

Several methods have been suggested to identify schistosome cercariae. In the present work, a new method is proposed, based on the analysis of the distribution of sensory endings (sensillae) on the body of the cercariae, revealed by an impregnation with silver nitrate. We determined the mutual distances between the sensillae and calculated the mean values, standard deviations, coefficients of asymmetry, and of kurtosis of the distribution of these mutual distances. Applied to two species, Schistosoma mansoni from Brazil and S. intercalatum from Cameroon, these mutual distances had the same mean value and the same standard deviation but quite different coefficients of symmetry (0.34 ± 0.11 versus 0.73 ± 0.08; P < 0.0001) and of kurtosis (-0.82 ± 0.27 versus -0.58 ± 0.31; P < 0.0001). The latter two indices were therefore very effective for discriminating the two species. The present method can be applied to other species and to hybrids in the field.

The average cell volume of rat adrenocortical zona fasciculata cells, determined using three different stains on semifine sections, was compared to that of dissociated, unfixed zona fasciculata cells. The maximum number of nuclei per area (NA) was obtained by counting nuclear profiles in semifine sections from nonosmicated adrenocortical tissue stained with toluidine blue. In osmicated adrenocortical tissue on the other hand, fewer nuclear profiles were seen and more of the small size classes were missing from the distribution of profiles. The skewness of the nuclear-profile distribution was much greater in osmicated than in nonosmicated tissue, reflecting the missing small profiles. Although the average diameter of nuclei (D) in nonosmicated tissue was smaller than that for osmicated tissue, profiles were in all likelihood more readily identified because they stained quite intensely. Three different methods for correcting nuclear-size profile distribution and determining nuclei per volume (NV) (Giger-Riedwyl, Cruz-Orive, and Weibel-Gomez) were generally in agreement for nonosmicated tissue. Considerable shrinkage occurred during preparation for electron microscopy, with the greater change occurring in nonosmicated tissue. Cell volume in osmicated tissue corrected for shrinkage varied considerably among the different methods, producing significantly greater values for cell volume than those in nonosmicated tissue. The cell volume of nonosmicated tissue, corrected for shrinkage during processing and for missing small nuclear profiles, did not differ significantly from that of freshly dissociated zona fasciculata cells. The one exception was nonosmicated tissue stained by Feulgen-methylene blue and corrected for missing small nuclear profiles by the method of Cruz-Orive. Use of nonosmicated adrenocortical tissue in stereological studies with an appropriate correction for shrinkage for each experiment is recommended for determining cell volume, although osmicated tissue should also be included to facilitate identification of intracellular membranes when electron microscopy is required.