80 research outputs found

    Are benthic fluxes important for the availability of Si in the Gulf of Finland?

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    We estimated the efflux of dissolved silicon (DSi) from sediments in the Gulf of Finland and compared it to sedimentation fluxes, burial of Si and existing data on Si loading and stocks, reassessing the reliability of existing Si budgets. Benthic fluxes of DSi measured in situ and in vitro were several times higher than estimates from diffusion calculations. The spatial variability in the open Gulf of Finland was relatively small, while both very high and low fluxes were measured from coastal areas. Fluxes were highest in late summer and lowest in early spring. In our re-assessed budget we present a new lower estimate for Si burial in the sediments, ca. 6 Gmol a(-1) and show that more than half of the sedimentation flux of Si is released back into the water column. Changes in the efficiency of internal DSi recycling may thus affect the prevalence of siliceous phytoplankton within the ecosystem, and the diatom spring bloom may be regulated by the functioning of this internal recycling pump. We also show that the seasonal variation in benthic DSi fluxes and dissolved phosphate fluxes is similar, and that a tentative connection between hypoLxia and high DSi efflux exists. (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe

    Comparing wood production and carbon sequestration after extreme thinnings in boreal Scots pine stands

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    Fennoscandian studies of thinning responses are usually limited to low thinning with moderate intensities. We studied here intermediate commercial thinning of different types (low, crown/normal, crown/strict, where respectively mostly intermediate and suppressed trees, mostly dominant and co-dominant trees, and only dominant trees were removed) and intensities (moderate and heavy) in Scots pine (Pinus sylvestris L.) dominated stands. We analysed their responses in terms of wood production and carbon balance. We investigated three stands in Southern and Middle Finland at the stage of second or third commercial thinning (age 34–50 years). We observed their development for fifteen years, and then we further simulated it with MOTTI stand simulator until final felling (scheduled either at age 65 or 80 years). We considered various variables of interest related to the thinning outputs, volume production after thinning, simulated final felling, and carbon balance. For all variables of interest, there were negligible differences across thinning types, and strong ones across thinning intensities. Thinning removals were significantly higher in heavy than moderate treatments, although only crown heavy thinnings had significantly higher sawlog output than low moderate. Volume growth post thinning during the 15-years observation was highest in unthinned plots, followed by moderate and then heavy treatments. For both total standing volume at simulated final fellings and carbon balance at any times, there was a similar descending trend from unthinned to moderate to heavy treatments. Concluding, the results suggest that crown/normal thinning could be applied with moderate intensity as alternative to low thinning, while heavy thinnings do not provide commercial benefits in Scots pine stands. Heavy intermediate thinnings in Scots pine stands provides lower total carbon accumulation during rotation, and early higher wood products (although not necessarily in terms of sawlogs) at the expense of later ones. Moderate thinning reached on site carbon neutrality after 5-years, while heavy thinning after 15 years

    Insulin-like growth factor binding protein 2 promotes ovarian cancer cell invasion

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    BACKGROUND: Insulin-like growth factor binding protein 2 (IGFBP2) is overexpressed in ovarian malignant tissues and in the serum and cystic fluid of ovarian cancer patients, suggesting an important role of IGFBP2 in the biology of ovarian cancer. The purpose of this study was to assess the role of increased IGFBP2 in ovarian cancer cells. RESULTS: Using western blotting and tissue microarray analyses, we showed that IGFBP2 was frequently overexpressed in ovarian carcinomas compared with normal ovarian tissues. Furthermore, IGFBP2 was significantly overexpressed in invasive serous ovarian carcinomas compared with borderline serous ovarian tumors. To test whether increased IGFBP2 contributes to the highly invasive nature of ovarian cancer cells, we generated IGFBP2-overexpressing cells from an SKOV3 ovarian cancer cell line, which has a very low level of endogenous IGFBP2. A Matrigel invasion assay showed that these IGFBP2-overexpressing cells were more invasive than the control cells. We then designed small interference RNA (siRNA) molecules that attenuated IGFBP2 expression in PA-1 ovarian cancer cells, which have a high level of endogenous IGFBP2. The Matrigel invasion assay showed that the attenuation of IGFBP2 expression indeed decreased the invasiveness of PA-1 cells. CONCLUSIONS: We therefore showed that IGFBP2 enhances the invasion capacity of ovarian cancer cells. Blockage of IGFBP2 may thus constitute a viable strategy for targeted cancer therapy

    What is the potential for replacing monocultures with mixed-species stands to enhance ecosystem services in boreal forests in Fennoscandia?

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    The boreal forests of Fennoscandia are largely dominated by Norway spruce and Scots pine. Conifer monocultures have been favoured in forest management during the last decades. Recently, concern has risen that forests consisting of only one tree species could be vulnerable to biotic damage. Additionally, environmental and societal changes are placing new demands on forest utilization, thus shifting the focus to alternative forest management options providing a wider scale of ecosystem services. It has been proposed that mixed forests are better than monocultures with respect to biodiversity, risk management and recreational value. By synthesising research studies, we provide an overview of current knowledge on how to combine wood production and other ecosystem services in mixed boreal forests in Fennoscandia. We addressed the following questions in more detail: what are the effects of mixed forests on soil properties, understorey vegetation, biodiversity, wildlife, resistance to and resilience against damage, forest productivity and the multiple use of forests? Furthermore, what are the silvicultural possibilities for establishing and managing mixed forests?Based on this review, mixed forests appear to provide a higher output of most ecosystem goods and services, including higher biodiversity and improved risk management, soil properties and multiple-use values. The most serious challenge is the browsing by cervids, which damages sapling stands. There is potential to establish single-storied mixed forests with current regeneration methods and material. Further research is particularly needed on the silvicultural practices suited for mixed boreal forests

    Bright Field Microscopy as an Alternative to Whole Cell Fluorescence in Automated Analysis of Macrophage Images

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    Fluorescence microscopy is the standard tool for detection and analysis of cellular phenomena. This technique, however, has a number of drawbacks such as the limited number of available fluorescent channels in microscopes, overlapping excitation and emission spectra of the stains, and phototoxicity.We here present and validate a method to automatically detect cell population outlines directly from bright field images. By imaging samples with several focus levels forming a bright field -stack, and by measuring the intensity variations of this stack over the -dimension, we construct a new two dimensional projection image of increased contrast. With additional information for locations of each cell, such as stained nuclei, this bright field projection image can be used instead of whole cell fluorescence to locate borders of individual cells, separating touching cells, and enabling single cell analysis. Using the popular CellProfiler freeware cell image analysis software mainly targeted for fluorescence microscopy, we validate our method by automatically segmenting low contrast and rather complex shaped murine macrophage cells.The proposed approach frees up a fluorescence channel, which can be used for subcellular studies. It also facilitates cell shape measurement in experiments where whole cell fluorescent staining is either not available, or is dependent on a particular experimental condition. We show that whole cell area detection results using our projected bright field images match closely to the standard approach where cell areas are localized using fluorescence, and conclude that the high contrast bright field projection image can directly replace one fluorescent channel in whole cell quantification. Matlab code for calculating the projections can be downloaded from the supplementary site: http://sites.google.com/site/brightfieldorstaining

    Chronic non-specific low back pain - sub-groups or a single mechanism?

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    Copyright 2008 Wand and O'Connell; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Low back pain is a substantial health problem and has subsequently attracted a considerable amount of research. Clinical trials evaluating the efficacy of a variety of interventions for chronic non-specific low back pain indicate limited effectiveness for most commonly applied interventions and approaches. Discussion: Many clinicians challenge the results of clinical trials as they feel that this lack of effectiveness is at odds with their clinical experience of managing patients with back pain. A common explanation for this discrepancy is the perceived heterogeneity of patients with chronic non-specific low back pain. It is felt that the effects of treatment may be diluted by the application of a single intervention to a complex, heterogeneous group with diverse treatment needs. This argument presupposes that current treatment is effective when applied to the correct patient. An alternative perspective is that the clinical trials are correct and current treatments have limited efficacy. Preoccupation with sub-grouping may stifle engagement with this view and it is important that the sub-grouping paradigm is closely examined. This paper argues that there are numerous problems with the sub-grouping approach and that it may not be an important reason for the disappointing results of clinical trials. We propose instead that current treatment may be ineffective because it has been misdirected. Recent evidence that demonstrates changes within the brain in chronic low back pain sufferers raises the possibility that persistent back pain may be a problem of cortical reorganisation and degeneration. This perspective offers interesting insights into the chronic low back pain experience and suggests alternative models of intervention. Summary: The disappointing results of clinical research are commonly explained by the failure of researchers to adequately attend to sub-grouping of the chronic non-specific low back pain population. Alternatively, current approaches may be ineffective and clinicians and researchers may need to radically rethink the nature of the problem and how it should best be managed

    The clinical course of low back pain: a meta-analysis comparing outcomes in randomised clinical trials (RCTs) and observational studies.

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    BACKGROUND: Evidence suggests that the course of low back pain (LBP) symptoms in randomised clinical trials (RCTs) follows a pattern of large improvement regardless of the type of treatment. A similar pattern was independently observed in observational studies. However, there is an assumption that the clinical course of symptoms is particularly influenced in RCTs by mere participation in the trials. To test this assumption, the aim of our study was to compare the course of LBP in RCTs and observational studies. METHODS: Source of studies CENTRAL database for RCTs and MEDLINE, CINAHL, EMBASE and hand search of systematic reviews for cohort studies. Studies include individuals aged 18 or over, and concern non-specific LBP. Trials had to concern primary care treatments. Data were extracted on pain intensity. Meta-regression analysis was used to compare the pooled within-group change in pain in RCTs with that in cohort studies calculated as the standardised mean change (SMC). RESULTS: 70 RCTs and 19 cohort studies were included, out of 1134 and 653 identified respectively. LBP symptoms followed a similar course in RCTs and cohort studies: a rapid improvement in the first 6 weeks followed by a smaller further improvement until 52 weeks. There was no statistically significant difference in pooled SMC between RCTs and cohort studies at any time point:- 6 weeks: RCTs: SMC 1.0 (95% CI 0.9 to 1.0) and cohorts 1.2 (0.7to 1.7); 13 weeks: RCTs 1.2 (1.1 to 1.3) and cohorts 1.0 (0.8 to 1.3); 27 weeks: RCTs 1.1 (1.0 to 1.2) and cohorts 1.2 (0.8 to 1.7); 52 weeks: RCTs 0.9 (0.8 to 1.0) and cohorts 1.1 (0.8 to 1.6). CONCLUSIONS: The clinical course of LBP symptoms followed a pattern that was similar in RCTs and cohort observational studies. In addition to a shared 'natural history', enrolment of LBP patients in clinical studies is likely to provoke responses that reflect the nonspecific effects of seeking and receiving care, independent of the study design

    Chick Embryo Partial Ischemia Model: A New Approach to Study Ischemia Ex Vivo

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    Background: Ischemia is a pathophysiological condition due to blockade in blood supply to a specific tissue thus damaging the physiological activity of the tissue. Different in vivo models are presently available to study ischemia in heart and other tissues. However, no ex vivo ischemia model has been available to date for routine ischemia research and for faster screening of anti-ischemia drugs. In the present study, we took the opportunity to develop an ex vivo model of partial ischemia using the vascular bed of 4th day incubated chick embryo. Methodology/Principal Findings: Ischemia was created in chick embryo by ligating the right vitelline artery using sterile surgical suture. Hypoxia inducible factor- 1 alpha (HIF-1a), creatine phospho kinase-MB and reactive oxygen species in animal tissues and cells were measured to confirm ischemia in chick embryo. Additionally, ranolazine, N-acetyl cysteine and trimetazidine were administered as an anti-ischemic drug to validate the present model. Results from the present study depicted that blocking blood flow elevates HIF-1a, lipid peroxidation, peroxynitrite level in ischemic vessels while ranolazine administration partially attenuates ischemia driven HIF-1a expression. Endothelial cell incubated on ischemic blood vessels elucidated a higher level of HIF-1a expression with time while ranolazine treatment reduced HIF-1a in ischemic cells. Incubation of caprine heart strip on chick embryo ischemia model depicted an elevated creatine phospho kinase-MB activity under ischemic condition while histology of the treated heart sections evoked edema and disruption of myofibril structures. Conclusions/Significance: The present study concluded that chick embryo partial ischemia model can be used as a novel ex vivo model of ischemia. Therefore, the present model can be used parallel with the known in vivo ischemia models in understanding the mechanistic insight of ischemia development and in evaluating the activity of anti-ischemic drug.status: publishe

    Genome-Wide Analysis of Effectors of Peroxisome Biogenesis

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    Peroxisomes are intracellular organelles that house a number of diverse metabolic processes, notably those required for β-oxidation of fatty acids. Peroxisomes biogenesis can be induced by the presence of peroxisome proliferators, including fatty acids, which activate complex cellular programs that underlie the induction process. Here, we used multi-parameter quantitative phenotype analyses of an arrayed mutant collection of yeast cells induced to proliferate peroxisomes, to establish a comprehensive inventory of genes required for peroxisome induction and function. The assays employed include growth in the presence of fatty acids, and confocal imaging and flow cytometry through the induction process. In addition to the classical phenotypes associated with loss of peroxisomal functions, these studies identified 169 genes required for robust signaling, transcription, normal peroxisomal development and morphologies, and transmission of peroxisomes to daughter cells. These gene products are localized throughout the cell, and many have indirect connections to peroxisome function. By integration with extant data sets, we present a total of 211 genes linked to peroxisome biogenesis and highlight the complex networks through which information flows during peroxisome biogenesis and function
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