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Biological Impact (biological + impact)
Selected AbstractsAnatomy of an overfill: a reflection on the processENDODONTIC TOPICS, Issue 1 2007ALAN H. GLUSKIN The design and implementation of shaping, cleaning and sealing objectives in root canal therapy are fraught with real and potential pitfalls when the anatomic complexity of the space and technical considerations for its instrumentation, disinfection and obturation are contemplated. This review will focus on the genesis of results that lead to endodontic overfills. We will look at how the literature defines overfill and overextension; attempt to address the consensus opinion on the definition of working length; and determine the effects of shaping geometry on overfill as well as the biological impact of obturation materials that go beyond the root canal space. In addition, this manuscript will highlight evidence for the prevention of overfills as well as focus on the local factors that affect repair and healing. [source] Genetic diversity of Clethrionomys glareolus populations from highly contaminated sites in the Chornobyl region, UkraineENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2000Cole W. Matson Abstract At radioactive sites, at least two mechanisms may affect the genetic diversity of populations of a given species. Increased mutation rates due to radiation exposure may increase the amount of genetic diversity in a population. Alternatively, population bottlenecks exacerbated by environmental degradation may lead to a reduction of diversity. The relationship between these two contradictory forces is complex. To explore this relationship, long-term monitoring of a genetic marker within a population is needed. To provide baseline data on the population genetics of the bank vole (Clethrionomys glareolus) living in the most contaminated regions at Chornobyl, Ukraine, we have sequenced 291 base pairs of the mitochondrial DNA control region. Bank voles were chosen as a model system because they have the highest levels of internal dose of cesium-134, cesium-137, and strontium-90 within the Chornobyl exclusion zone. We sampled three geographic sites, which were Oranoe, a reference site with virtually no radioactive contamination (<2 Ci/km2), and two highly contaminated sites, Glyboke Lake and the Red Forest (both 1,000 Ci/km2). Genetic diversity in the population from Red Forest (0.722 ± 0.024) was significantly greater than at the Oranoe reference site (0.615 ± 0.039), while genetic diversity at Glyboke Lake (0.677 ± 0.068) was intermediate. It is concluded that long-term studies of historical and demographic characteristics for experimental and reference populations are required in order to employ population genetics to understand the biological impact of environmental contaminants on the genetics of natural populations. [source] Complete high-density lipoproteins in nanoparticle coronaFEBS JOURNAL, Issue 12 2009Erik Hellstrand In a biological environment, nanoparticles immediately become covered by an evolving corona of biomolecules, which gives a biological identity to the nanoparticle and determines its biological impact and fate. Previous efforts at describing the corona have concerned only its protein content. Here, for the first time, we show, using size exclusion chromatography, NMR, and pull-down experiments, that copolymer nanoparticles bind cholesterol, triglycerides and phospholipids from human plasma, and that the binding reaches saturation. The lipid and protein binding patterns correspond closely with the composition of high-density lipoprotein (HDL). By using fractionated lipoproteins, we show that HDL binds to copolymer nanoparticles with much higher specificity than other lipoproteins, probably mediated by apolipoprotein A-I. Together with the previously identified protein binding patterns in the corona, our results imply that copolymer nanoparticles bind complete HDL complexes, and may be recognized by living systems as HDL complexes, opening up these transport pathways to nanoparticles. Apolipoproteins have been identified as binding to many other nanoparticles, suggesting that lipid and lipoprotein binding is a general feature of nanoparticles under physiological conditions. [source] Interplay between global patterns of environmental temperature and variation in nonshivering thermogenesis of rodent species across large spatial scalesGLOBAL CHANGE BIOLOGY, Issue 9 2009ENRIQUE RODRÍGUEZ-SERRANO Abstract The purpose of this study was to test for correlations of mass-independent nonshivering thermogenesis (NST) in rodent species with climatic factors such as maximum and minimum geographic temperature. We first analyzed whether the responses of rodents show a phylogenetic signal. If so, and if the NST over a broad geographical range is similar, then such responses probably reflect physiological evolutionary adaptation. Our results show that NST did not show phylogenetic signal, appears to be evolutionary labile and is negatively correlated with environmental temperature. We predicted that species evolved in cold climates will exhibit higher mass-independent NST than species from warmer habitats. Indeed, we observed that the relationships between mass-independent NST and minimum temperature (rs=,0.411, P=0.009) as well as between NST and maximum temperature (rs=,0.443, P=0.004) were both negatively and significantly correlated, thus supporting our predictions. Thus, thermal physiology may be a significant factor underlying the ecological and evolutionary success of animals. Finally we suggest that due to the pressing need to explain and predict the likely biological impact of climatic change, advances in this field are necessary. [source] A specific GFP expression assay, penetrance estimate, and histological assessment for a putative splice site mutation in BRCA1,HUMAN MUTATION, Issue 1 2003M.C. Southey Abstract Genetic testing for cancer predisposing mutations in BRCA1 and BRCA2 has been of benefit to many individuals from breast and ovarian cancer-prone kindreds. However, a function has not been assigned to many of the domains that make up these complex proteins and hence, the significance of many sequence variants, including missense mutations, splice-site mutations, and in-frame deletions/insertions, remains unclear. We identified a putative splice site mutation (IVS6-2delA) in BRCA1 in a family attending a Familial Cancer Centre that had a significant history of both breast and ovarian cancer. This sequence variant was not novel but the exact effect on mRNA splicing and hence the biological impact of this sequence variation was unclear and therefore the finding was unable to be used in genetic counseling of the family. Via the construction of novel GFP-based expression fusion constructs, we demonstrated that this sequence variation prevented normal splicing of the BRCA1 transcript. By combining these data with an assessment of the histopathological features of the breast carcinomas in this family and mutation penetrance estimate we were able to conclude that this BRCA1 variant conveyed an increased risk of breast cancer. Hum Mutat 22:86,91, 2003. © 2003 Wiley-Liss, Inc. [source] Quantitative Ultrasound Assessment in Children With Fractures,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2004Johannes Schalamon Abstract BMD of children with fractures was compared with healthy controls using QUS. We found significantly lower SOS values in children suffering from fractures. None of the studied environmental factors could explain the difference in BMD measurements. Introduction: The aims of this study were to compare the results of quantitative ultrasound (QUS) in children with fractures with the respective values in children without fractures and to identify possible environmental factors influencing speed of sound (SOS) in our study cohort. Materials and Methods: BMD was measured by QUS in 50 children who had sustained an acute fracture and in 154 healthy children as controls. SOS values were obtained from the proximal phalanges of the last four fingers of the dominant hand. Nutritional habits and activity level of the children were documented by a standardized questionnaire. Results: Children with fractures had a significantly lower SOS compared with children without a history of fractures. This difference in SOS could not be explained by differences in diet, body mass index, or physical activity. Conclusions: Previous studies have suggested that low BMD levels might contribute to an increased prevalence of fractures in patients with systemic diseases. Our study showed that, in an otherwise healthy pediatric population, the SOS values are lower in children with fractures compared with healthy controls. Despite statistical significance, the biological impact of the results remains unclear. The difference in SOS values could not be explained by any of the studied environmental factors. [source] CLIMATE CHANGE AND FISHERIES: ASSESSING THE ECONOMIC IMPACT IN ICELAND AND GREENLANDNATURAL RESOURCE MODELING, Issue 2 2007RAGNAR ARNASON ABSTRACT. . Climate changes in the 21st century are expected to significantly increase ocean temperatures and modify other oceanographic conditions in the North Atlantic. Marine biological research suggests that the impacts on the commercially most important fish stocks in the Icelandic-Greenland ecosystem may well be quite substantial. This will obviously lead to a corresponding impact on the economies of these two countries. However, the timing, extent and biological impact of global warming is quite uncertain. As a result the economic impact is similarly uncertain. This paper attempts to provide estimates of the impact of altered fish stocks due to global warming on the Icelandic and Greenland economies. The approach is one of stochastic simulations. This involves essentially three steps. The first is to obtain predictions of the impact of global warming on fish stocks and the associated probability distribution. For this we rely on recent marine biological predictions. The second step is to estimate the role of the fisheries sector in the two economies. This is done with the help of modern econometric techniques based on economic growth theory and historical data. Obviously these estimates are also subject to stochastic errors and uncertainty. The third step is to carry out Monte Carlo simulations on the basis of the above model and the associated uncertainties. The result of the Monte Carlo simulations consists of a set of dynamic paths for GDP over time with an expected value and a probability distribution for each future year. On this basis it is possible to calculate confidence intervals for the most likely path of GDP over time. The results indicate that the fisheries impact of global warming on the Icelandic GDP is more likely to be positive than negative but unlikely to be of significant magnitude compared to historical economic growth rates and fluctuations. The uncertainty of this prediction, however, is large. For Greenland, the impact on fish stocks and the GDP is highly likely to be positive and quite substantial relative to the current GDP. Due to less knowledge of the relationship between the fisheries sector and the Greenland economy, however, the confidence interval of this prediction is even wider than in the case of Iceland. [source] The presence of Rickettsia is associated with increased susceptibility of Bemisia tabaci (Homoptera: Aleyrodidae) to insecticidesPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 8 2008Svetlana Kontsedalov Abstract BACKGROUND: The presence of certain symbiotic microorganisms may be associated with insecticide resistance in insects. The authors compared the susceptibility of two isofemale lines, Rickettsia -plus and Rickettsia -free, of the sweet potato whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) to major insecticides from different chemical groups, including imidacloprid, acetamiprid, thiamethoxam, pyriproxyfen, spiromesifen and diafenthiuron. RESULTS: While the Rickettsia -plus and Rickettsia -free lines showed no differences in their susceptibility to imidacloprid and diafenthiuron, higher susceptibility of the Rickettsia -plus line to acetamiprid, thiamethoxam, spiromesifen and especially pyriproxyfen was observed. LC90 values indicated that the Rickettsia -free line was 15-fold more resistant to pyriproxyfen than the Rickettsia -plus line. CONCLUSION: Findings indicate that the infection status of B. tabaci populations by Rickettsia is an important consideration that should be taken into account when performing resistance monitoring studies, and may help in understanding the dynamics of B. tabaci resistance, symbiont-pest associations in agricultural systems and the biological impact of Rickettsia on whitefly biology. Copyright © 2008 Society of Chemical Industry [source] Evaluating for long-term impact of an environmental education program at the Kalinzu Forest Reserve, UgandaAMERICAN JOURNAL OF PRIMATOLOGY, Issue 5 2010C.W. Kuhar Abstract Although the importance of evaluating the effectiveness of conservation education programs cannot be underestimated, few evaluations of these programs and their resulting impact on the environment have been conducted. A partnership between scientists, educators, and local administrators on an evaluation program has been developed to evaluate a model of education program evaluation that includes short- and long-term evaluation of (1) knowledge and attitude change, (2) behavior change, and (3) positive biological impact. Previous work has shown short-term knowledge retention from this education program. In the current study follow-up evaluations were collected from students at 14 schools outside the Kalinzu Forest Reserve, Uganda. By comparing performance 30 days, 1 year and 2 years after the initial program we demonstrate that knowledge gain from this program is not transient. However, although knowledge is a prerequisite for appropriate conservation actions it does not guarantee appropriate behaviors will be performed. Anecdotal evidence of behavior change and positive biological impact is discussed within the context of the challenges with changing behavior and evaluating the true biological impacts of those behaviors. Ultimately, conservation professionals will need to partner with educators and social scientists to effectively measure the impact of conservation education and human-based conservation programs on primate populations and their habitat. Am. J. Primatol. 72:407,413, 2010. © 2009 Wiley-Liss, Inc. [source] Dynamics of the ion cyclotron resonance effect on amino acids adsorbed at the interfacesBIOELECTROMAGNETICS, Issue 1 2006N. Comisso Abstract In this study we show a reproduction of the Zhadin experiment, which consists of the transient increase of the electrolytic current flow across an aqueous solution of L -arginine and L -glutamic acid induced by a proper low frequency alternating magnetic field superimposed to a static magnetic field of higher strength. We have identified the mechanisms that were at the origin of the so-far poor reproducibility of the above effect: the state of polarization of the electrode turned out to be a key parameter. The electrochemical investigation of the system shows that the observed phenomenon involves the transitory activation of the anode due to ion cyclotron frequency effect, followed again by anode passivation due to the adsorption of amino acid and its oxidation products. The likely occurrence of similar ion cyclotron resonance (ICR) phenomena at biological membranes, the implications on ion circulation in living matter, and the consequent biological impact of environmental magnetic fields are eventually discussed. Bioelectromagnetics 27:16,25, 2006. © 2005 Wiley-Liss, Inc. [source] Cell death induction by isothiocyanates and their underlying molecular mechanismsBIOFACTORS, Issue 2 2006Yoshimasa Nakamura Abstract An important and promising group of compounds that have a chemopreventive property are organosulfur compounds, such as isothiocyanates (ITCs). In recent years, it has been shown that ITCs induce apoptosis in various cancer cell lines and experimental rodents. During the course of apoptosis induction by ITC, multiple signal-transduction pathways and apoptosis intermediates are modulated. We have also clarified the molecular mechanism underlying the relationship between cell cycle arrest and apoptosis induced by benzyl isothiocyanate (BITC), a major ITC compound isolated from papaya. The exposure of cells to BITC resulted in the inhibition of the G2/M progression that coincided with not only the up-regulated expression of the G2/M cell cycle arrest-regulating genes but also the apoptosis induction. The experiment using the phase-specific synchronized cells demonstrated that the G2/M phase-arrested cells are more sensitive to undergoing apoptotic stimulation by BITC than the cells in other phases. We identified the phosphorylated Bcl-2 as a key molecule linking the p38 MAPK-dependent cell cycle arrest with the JNK activation by BITC. We also found that BITC induced the cytotoxic effect more preferentially in the proliferating normal human colon epithelial cells than in the quiescent cells. Conversely, treatment with an excessive concentration of BITC resulted in necrotic cell death without DNA ladder formation. This review addresses the biological impact of cell death induction by BITC as well as other ITCs and the involved signal transduction pathways. [source] CMR2009: 11.05: Noninvasive detection and biological impacts of injected single-walled carbon nanotubes (SWCNT) using MR techniquesCONTRAST MEDIA & MOLECULAR IMAGING, Issue 6 2009A. Al Faraj No abstract is available for this article. [source] Climate change scenarios and models yield conflicting predictions about the future risk of an invasive species in North AmericaAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2010Anna M. Mika 1The pea leafminer Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae) is an invasive species in North America and a serious economic pest on a wide variety of crops. We developed a bioclimatic envelope model (BEM) for this species and examined the envelope's potential location in North America under various future climates. 2We compared the future bioclimatic envelopes for L. huidobrensis using either simple scenarios comprising uniform changes in temperature/precipitation or climate projections from general circulation models (GCMs). Our simple scenarios were: (i) an increase of 0.1°C per degree in latitude with a 20% increase in summer precipitation and a 20% decrease in winter precipitation and (ii) an overall increase of 3°C everywhere, also with the same changes in precipitation. For GCM-modelled climate change, we used the Canadian Centre for Climate Modelling and Analysis GCM (CGCM2) and the Hadley Centre climate model (HadCM3), each in combination with two scenarios from the Special Report on Emissions Scenarios (A2 and B2). 3The BEM results using the simple scenarios were more similar to each other than to the results obtained using GCM projections. The results were also qualitatively different (i.e. spatially different and divergent) depending on which GCM-scenario combination was used. 4This modelling exercise illustrates that: (i) results using first approximation simple climate change scenarios can give predictions very different from those that use GCM-modelled climate projections (comprising a result that has worrying implications for empirical impact research) and that (ii) different GCM-models using the same scenario can give very different results (implying strong model dependency in projected biological impacts). [source] Evaluating for long-term impact of an environmental education program at the Kalinzu Forest Reserve, UgandaAMERICAN JOURNAL OF PRIMATOLOGY, Issue 5 2010C.W. Kuhar Abstract Although the importance of evaluating the effectiveness of conservation education programs cannot be underestimated, few evaluations of these programs and their resulting impact on the environment have been conducted. A partnership between scientists, educators, and local administrators on an evaluation program has been developed to evaluate a model of education program evaluation that includes short- and long-term evaluation of (1) knowledge and attitude change, (2) behavior change, and (3) positive biological impact. Previous work has shown short-term knowledge retention from this education program. In the current study follow-up evaluations were collected from students at 14 schools outside the Kalinzu Forest Reserve, Uganda. By comparing performance 30 days, 1 year and 2 years after the initial program we demonstrate that knowledge gain from this program is not transient. However, although knowledge is a prerequisite for appropriate conservation actions it does not guarantee appropriate behaviors will be performed. Anecdotal evidence of behavior change and positive biological impact is discussed within the context of the challenges with changing behavior and evaluating the true biological impacts of those behaviors. Ultimately, conservation professionals will need to partner with educators and social scientists to effectively measure the impact of conservation education and human-based conservation programs on primate populations and their habitat. Am. J. Primatol. 72:407,413, 2010. © 2009 Wiley-Liss, Inc. [source] Decadal changes (1996,2006) in coastal ecosystems of the Chagos archipelago determined from rapid assessmentAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 6 2009Andrew R.G. Price Abstract 1.The atolls and islands comprising Chagos are a biodiversity hotspot of global conservation significance in a remote part of the central Indian Ocean. 2.This study examines the condition of the archipelago's coastal ecosystems by rapid environmental assessment at 21 sites/islands, which were also investigated a decade earlier using the same methodology. Major changes in ecosystem structure and environmental disturbance were determined. 3.Coral fish abundance was significantly lower in 2006 than 1996. Decrease in the physical structural complexity of the reefs, as a result of coral bleaching and mortality induced by the 1998 warming event, may have been a contributing factor. 4.Evidence of collecting/fishing was significantly greater in 2006 than 1996. This is attributed mainly to an illegal fishery for holothurians (sea cucumbers), which has expanded over recent years and now exerts substantial pressure on the resource. The significant decline observed in beach wood, a readily accessible fuel for fishing camps, is consistent with this. 5.Solid waste on islands was high (median 2 to 20 items m,1 beach) in both 1996 and 2006. Potentially harmful biological impacts, determined from other studies, include entanglement, toxic effects and provision of transport for invasives or other ,hitchhiker' species. 6.Significantly higher bird abundances were recorded in protected areas than ,unprotected' areas, attributed mainly to absence of predation by rats. 7.Rapid assessment augments more comprehensive ecosystem investigations. It provides a valuable snapshot of environmental conditions based upon a broad suite of features (ecosystems and disturbances) determined, concurrently, within the same site inspection quadrats and using the same scale of assessment. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||||||||