No effects of UMTS exposure on the function of rat outer hair cells

UMTS communication devices are becoming common in everyday use. This could raise public concern about their possible detrimental effects on human health. The aim of this study, in the framework of the EMF nEAR Project, was to evaluate possible influence of UMTS electromagnetic fields (EMF) exposure on cochlear outer hair cells' (OHCs) functionality in laboratory animals. Forty‐eight male Sprague–Dawley rats were locally exposed (right ear) or sham‐exposed to a controlled UMTS EMF, frequency of 1946 MHz, at SAR level of 10 W/kg, 2 h a day, 5 days a week, for 4 weeks. A group of 12 rats treated with kanamycin (KM) was also included as positive control. Rats were tested by recording Distortion Product Otaoacoustic Emissions (DPOAEs), a non‐invasive test capable of assessing the status of the OHCs in the inner ear. DPOAEs were performed before, during (one or three times a week) and after (1‐week) exposure to the EMF. The analysis of the data shows that no statistically significant differences were found between the audiological signals recorded from the different experimental groups. The ototoxic effect of KM has been confirmed. Bioelectromagnetics 30:385–392, 2009. © 2009 Wiley‐Liss, Inc.     

Enhancement of growth rate and β-galactosidase activity, and variation in organic acid profile of Bifidobacterium animalis subsp. lactis Bb 12

The behavior of Bifidobacterium animalis subsp. lactis Bb 12 under batch cultivation, after continuous culturing for up to 12 d, was monitored in skim milk-based media. Previous continuous culture for longer than 6 d affected the physiology of said microorganism. The minimum inhibitory concentrations of lactic and acetic acids increased from 18 to 26 g/l, whereas the molar ratio of acetic to lactic acid increased from 0.8 to 1.55, when the previous continuous culture increased its duration from 1 to 12 d. The specific lactose consumption rate decreased from 0.94 to 0.77 g_lactose/g_{cell dry mass}/h within the batch culture timeframe; this was concomitant with greater amounts of acetic and formic acids, and lower amounts of lactic acid produced. The β-galactosidase activity increased as continuous culturing time increased, and reached 446 units/ml by 12 d; however, the rate of enzyme synthesis decreased concomitantly. Succinic acid was produced during the exponential growth and stationary phases of the batch culture, but the former at exponential growth phase was higher as the continuous culturing time was longer. For comparison purposes, batch cultivation of samples taken from continuous cultures by 1 and 12 d was done using a semi-synthetic medium with glucose as carbon source; a pattern similar to that observed when using skim milk-based media was observed.     

集群式院外高危心脏病患者远程实时连续监护系统

设计了一种针对院外心血管病患者的远程心电监护系统,包括便携式监护终端和医院监护中心。其特点在于可对身处院外、自由活动的心血管病患者进行远程、实时、连续的监护,同时获得被监护患者的地理位置信息。已完成的整体调试结果表明,本系统不仅能及时发现异常心电图并进行干预,而且还可根据地理位置信息对突发急病的患者进行快速救治。该系统是院内监护系统功能的延伸,有良好的临床应用前景。     

When the exception becomes the rule: The disappearance of limiting similarity in the Lotka-Volterra model

We investigate the transition between limiting similarity and coexistence of a continuum in the competitive Lotka-Volterra model. It is known that there exist exceptional cases in which, contrary to the limiting similarity expectation, all phenotypes coexist along a trait axis. Earlier studies established that the distance between surviving phenotypes is in the magnitude of the niche width 2σ provided that the carrying capacity curve differs from the exceptional one significantly enough. In this paper we studied the outcome of competition for small perturbations of the exceptional (Gaussian) carrying capacity. We found that the average distance between the surviving phenotypes goes to zero when the perturbation vanishes. The number of coexisting species in equilibrium is proportional to the negative logarithm of the perturbation. Nevertheless, the niche width provides a good order of magnitude for the distance between survivors if the perturbations are larger than 10%. Therefore, we conclude that limiting similarity is a good framework of biological thinking despite the lack of an absolute lower bound of similarity.     

Evaluating the efficacy of continuous quantitative characters for reconstructing the phylogeny of a morphologically homogeneous spider taxon (Araneae, Mygalomorphae, Antrodiaetidae, Antrodiaetus)

The use of continuous quantitative characters for phylogenetic analyses has long been contentious in the systematics literature. Recent studies argue for and against their use, but there have been relatively few attempts to evaluate whether these characters provide an accurate estimate of phylogeny, despite the fact that a number of methods have been developed to analyze these types of data for phylogenetic inference. A tree topology will be produced for a given methodology and set of characters, but little can be concluded with regards to the accuracy of phylogenetic signal without an independent evaluation of those characters. We assess the performance of continuous quantitative characters for the mygalomorph spider genus Antrodiaetus, a group that is morphologically homogeneous and one for which few discrete (morphological) characters have been observed. Phylogenetic signal contained in continuous quantitative characters is compared to an independently derived phylogeny inferred on the basis of multiple nuclear and mitochondrial gene loci. Tree topology randomizations, regression techniques, and topological tests all demonstrate that continuous quantitative characters in Antrodiaetus conflict with the phylogenetic signal contained in the gene trees. Our results show that the use of continuous quantitative characters for phylogenetic reconstruction may be inappropriate for reconstructing Antrodiaetus phylogeny and indicate that due caution should be exercised before employing this character type in the absence of other independently derived sources of characters.     

Seedling regeneration,environment and management in a semi‐deciduous African tropical rain forest

Questions: How is seedling regeneration of woody species of semi‐deciduous rain forests affected by (a) historical management for combinations of logging, arboricide treatment or no treatment, (b) forest community type and (c) environmental gradients of topography, light and soil nutrients? Location: Budongo Forest Reserve, Uganda. Methods: Seedling regeneration patterns of trees and shrubs in relation to environmental factors and historical management types were studied using 32 0.5‐ha plots laid out in transects along a topographic gradient. We compared seedling species diversity, composition and distribution patterns along topographic gradients and within types of historical management regimes and forest communities to test whether environmental factors contributed to differences in species composition of seedlings. Results: A total of 85 624 woody seedlings representing 237 species and 46 families were recorded in this rain forest. Cynometra alexandri C.H. Wright and Lasiodiscus mildbraedii Engl. had high seedling densities and were widely distributed throughout the plots. The most species‐rich families were Euphorbiaceae, Fabaceae, Rubiaceae, Meliaceae, Moraceae and Rutaceae. Only total seedling density was significantly different between sites with different historical management, with densities highest in logged, intermediate in logged/arboricided and lowest in the nature reserve. Forest communities differed significantly in terms of seedling diversity and density. Seedling composition differed significantly between transects and forest communities, but not between topographic positions or historical management types. Both Chao‐Jaccard and Chao‐Sørensen abundance‐based similarity estimators were relatively high in the plot, forest community and in terms of historical management levels, corroborating the lack of significant differences in species richness within these groups. The measured environmental variables explained 59.4% of variance in seedling species distributions, with the three most important being soil organic matter, total soil titanium and leaf area index (LAI). Total seedling density was positively correlated with LAI. Differences in diversity of >2.0 cm dbh plants (juveniles and adults) also explained variations in seedling species diversity. Conclusions: The seedling bank is the major route for regeneration in this semi‐deciduous tropical rain forest, with the wide distribution of many species suggesting that these species regenerate continuously. Seedling diversity, density and distribution are largely a function of adult diversity, historical management type and environmental gradients in factors such as soil nutrient content and LAI. The species richness of seedlings was higher in soils both rich in titanium and with low exchangeable cations, as well as in logged areas that were more open and had a low LAI.     

Effects of continuous and pulsatile PTH treatments on rat bone marrow stromal cells

Bone marrow stromal cells (MSCs) differentiation and proliferation are controlled by numerous growth factors and hormones. Continuous parathyroid hormone (PTH) treatment has been shown to decrease osteoblast differentiation, whereas pulsatile PTH increases osteoblast differentiation. However, the effects of PTH treatments on MSCs have not been investigated. This study showed continuous PTH treatment in the presence of dexamethasone (DEX) promoted osteogenic differentiation of rat MSCs in vitro, as demonstrated by increased alkaline phosphatase (ALP) activity, number of ALP expressing cells, and up-regulation of PTH receptor-1, ALP, and osteocalcin mRNA expressions. In contrast, pulsatile PTH treatment was found to suppress osteogenesis of rat MSCs, possibly by promoting the maintenance of undifferentiated cells. Additionally, the observed effects of PTH were strongly dependent on the presence of DEX. MSC proliferation however was not influenced by PTH independent of treatment regimen and presence or absence of DEX. Furthermore, our work raised the possibility that PTH treatment may modulate stem/progenitor cell activity within MSC cultures.     

A closed-loop artificial pancreas based on model predictive control: Human-friendly identification and automatic meal disturbance rejection

Type 1 diabetes is characterized by a lack of insulin production by the pancreas, causing high blood glucose concentrations and requiring external insulin infusion to regulate blood glucose. Continuous glucose sensors can be coupled with continuous insulin infusion pumps to create a closed-loop artificial pancreas. A novel procedure of “human-friendly” identification testing using multisine inputs is developed to estimate suitable models for use in an artificial pancreas. A constrained model predictive control (MPC) strategy is developed to reduce risks of hypo- and hyperglycemia (low and high blood glucose concentration). Meal detection and meal size estimation algorithms are developed to improve meal glucose disturbance rejection when incoming meals are not announced. Closed-loop performance is evaluated through simulation studies of a type 1 diabetic individual, illustrating the ability of the MPC-based artificial pancreas control strategy to handle announced and unannounced meal disturbances.     

Analysis of three-dimensional SAR distributions emitted by mobile phones in an epidemiological perspective

The three‐dimensional distribution of the specific absorption rate of energy (SAR) in phantom models was analysed to detect clusters of mobile phones producing similar spatial deposition of energy in the head. The clusters' characteristics were described from the phones external features, frequency band and communication protocol. Compliance measurements with phones in cheek and tilt positions, and on the left and right side of a physical phantom were used. Phones used the Personal Digital Cellular (PDC), Code division multiple access One (CdmaOne), Global System for Mobile Communications (GSM) and Nordic Mobile Telephony (NMT) communication systems, in the 800, 900, 1500 and 1800 MHz bands. Each phone's measurements were summarised by the half‐ellipsoid in which the SAR values were above half the maximum value. Cluster analysis used the Partitioning Around Medoids algorithm. The dissimilarity measure was based on the overlap of the ellipsoids, and the Manhattan distance was used for robustness analysis. Within the 800 MHz frequency band, and in part within the 900 MHz and the 1800 MHz frequency bands, weak clustering was obtained for the handset shape (bar phone, flip with top and flip with central antennas), but only in specific positions (tilt or cheek). On measurements of 120 phones, the three‐dimensional distribution of SAR in phantom models did not appear to be related to particular external phone characteristics or measurement characteristics, which could be used for refining the assessment of exposure to radiofrequency energy within the brain in epidemiological studies such as the Interphone. Bioelectromagnetics. Bioelectromagnetics 32:634–643, 2011. © 2011 Wiley Periodicals, Inc.