912 research outputs found
Spatial monsoon variability with respect to NAO and SO
In this paper, the simultaneous effect of North Atlantic Oscillation (NAO) and Southern Oscillation (SO) on monsoon rainfall over different homogeneous regions/subdivisions of India is studied. The simultaneous effect of both NAO and SO on Indian summer monsoon rainfall (ISMR) is more important than their individual impact because both the oscillations exist simultaneously throughout the year. To represent the simultaneous impact of NAO and SO, an index called effective strength index (ESI) has been defined on the basis of monthly NAO and SO indices. The variation in the tendency of ESI from January through April has been analyzed and reveals that when this tendency is decreasing, then the ESI value throughout the monsoon season (June-September) of the year remains negative and vice versa. This study further suggests that during the negative phase of ESI tendency, almost all subdivisions of India show above-normal rainfall and vice versa. The correlation analysis indicates that the ESI-tendency is showing an inverse and statistically significant relationship with rainfall over 14 subdivisions of India. Area wise, about 50 of the total area of India shows statistically significant association. Moreover, the ESI-tendency shows a significant relationship with rainfall over north west India, west central India, central north east India, peninsular India and India as a whole. Thus, ESI-tendency can be used as a precursor for the prediction of Indian summer monsoon rainfall on a smaller spatial scale
Dynamic structural colour increases photosynthetic performance in the alga Ericaria selaginoides
Efficient, Unbiased Quality Assurance Of Automated Tissue Analysis Applicable To Daily Pathology Practice
Introduction/ Background
Quantification of tissue biomarkers is increasingly demanded for diagnosis and is commonly performed by expert pathologists using microscopy of stained tissue at high magnification. This manual scoring is a reasonably fast, supervised procedure, but it suffers from inter- and intra-observer differences due to a) differences in selection of regions of interest, b) differences in quantity estimation, c) intra-tissue variability of biomarker expression. Computers and whole slide microscopy scanners have made it feasible to perform high-capacity analysis of high resolution images of tissue. Image analysis (IA) enables better reproducibility, but conversely, the unsupervised analysis introduces challenges regarding accuracy. Furthermore, borderline cases will always have to be rigorously inspected by pathologists.
Many IA evaluation methods exist, but for pathology, a supervised comparison of experimental segmentation to an appropriately obtained standard criterion is the optimal strategy. The production of standard criterion necessitates evaluation of whole slide images to eliminate any possible region sampling bias while inter- and intra- observer bias can only be minimized by replacing any manual estimates by objective measurements.
A logical step is thus to change the task of the pathologist from quantity estimation to verifying the output an automated procedure reports. Still, verification of entire tissue slides is in daily pathology practice too time-consuming. To minimize the workload pathology is turning to stereological methods which aim to efficiently quantify matter unbiasedly and have been proved useful for supervised validation of automated analysis for Ki67 scoring of breast cancer. However, the workload still needs to be reduced to a level comparable to the manual scoring procedure.
Aims
We aim to enable high accuracy, objective evaluation of automated image analysis with a workload and workflow feasible for daily pathology practice. This regards both production of reference data for image analysis tool calibration and continuous quality control inspection of borderline cases.
Methods
This study investigates proportionate sampling, a very efficient stereological sampling scheme utilizing weighted sampling of regions of automated image analysis for manual evaluation of automated IA. The sampling of regions to be inspected by a pathologist draws upon the IA to assign probability weights to all regions. This results in a highly efficient, unbiased sampling and quality assurance estimate for the automated image analysis.
Results
Presented here is proof-of-concept of an efficient, unbiased image analysis evaluation methodology. The task of the pathologist is changed from quantity estimation to instead annotate discrepancies between the output from the IA and the tissue in a few sampled regions. From the annotations an unbiased quality assurance estimate of the IA can be estimated including levels of accuracy obtainable and expected workloads.
This confirms that the stereological proportionate sampling enables manual verification of automated whole slide image analysis for unbiased reference dataset creation and quality control inspection in borderline cases. Furthermore, the methodology is easily integrated into both image analysis platforms for production of reference data sets and laboratory information systems for daily pathology practices.
Mitochondria-derived reactive oxygen species are the likely primary trigger of mitochondrial retrograde signaling in Arabidopsis.
Besides their central function in respiration, plant mitochondria play a crucial role in maintaining cellular homeostasis during stress by providing "retrograde" feedback to the nucleus. Despite the growing understanding of this signaling network, the nature of the signals that initiate mitochondrial retrograde regulation (MRR) in plants remains unknown. Here, we investigated the dynamics and causative relationship of a wide range of mitochondria-related parameters for MRR, using a combination of Arabidopsis fluorescent protein biosensor lines, in vitro assays, and genetic and pharmacological approaches. We show that previously linked physiological parameters, including changes in cytosolic ATP, NADH/NAD+ ratio, cytosolic reactive oxygen species (ROS), pH, free Ca2+, and mitochondrial membrane potential, may often be correlated with-but are not the primary drivers of-MRR induction in plants. However, we demonstrate that the induced production of mitochondrial ROS is the likely primary trigger for MRR induction in Arabidopsis. Furthermore, we demonstrate that mitochondrial ROS-mediated signaling uses the ER-localized ANAC017-pathway to induce MRR response. Finally, our data suggest that mitochondrially generated ROS can induce MRR without substantially leaking into other cellular compartments such as the cytosol or ER lumen, as previously proposed. Overall, our results offer compelling evidence that mitochondrial ROS elevation is the likely trigger of MRR
Formation of Composite Endothelial Cell–Mesenchymal Stem Cell Islets: A Novel Approach to Promote Islet Revascularization
OBJECTIVE—Mesenchymal stem cells (MSCs) contribute to endothelial cell (EC) migration by producing proteases, thereby paving the way into the tissues for ECs. MSCs were added to our previously described composite EC islets as a potential means to improve their capacity for islet angiogenesis
Registration of ‘Quest’ spring malting barley with improved resistance to Fusarium head blight
‘Quest’ (Reg No. CV-348, PI 663183) is a spring, six-rowed, malting barley (Hordeum vulgare L.) released by the Minnesota Agricultural Experiment Station in January 2010 on the basis of its improved resistance to Fusarium head blight [FHB; caused by Fusarium graminearum Schwabe; teleomorph Gibberella zeae (Schwein) Petch]. Quest was developed over three breeding cycles of selection for yield, malting quality, and FHB resistance. Disease resistance traces to the Midwest cultivar MNBrite and the two-rowed accession from China Zhedar1. Quest has about half the level of disease and about 40% less of the associated mycotoxin, deoxynivalenol, compared to the historically important cultivar in the region ‘Robust’. Quest is similar in yield to the current dominant varieties in the region and was approved as a malting variety by the American Malting Barley Association
Cadmium and lead accumulate in the deciduous teeth of children with celiac disease or food allergies
Membranes with the Same Ion Channel Populations but Different Excitabilities
Electrical signaling allows communication within and between different tissues and is necessary for the survival of multicellular organisms. The ionic transport that underlies transmembrane currents in cells is mediated by transporters and channels. Fast ionic transport through channels is typically modeled with a conductance-based formulation that describes current in terms of electrical drift without diffusion. In contrast, currents written in terms of drift and diffusion are not as widely used in the literature in spite of being more realistic and capable of displaying experimentally observable phenomena that conductance-based models cannot reproduce (e.g. rectification). The two formulations are mathematically related: conductance-based currents are linear approximations of drift-diffusion currents. However, conductance-based models of membrane potential are not first-order approximations of drift-diffusion models. Bifurcation analysis and numerical simulations show that the two approaches predict qualitatively and quantitatively different behaviors in the dynamics of membrane potential. For instance, two neuronal membrane models with identical populations of ion channels, one written with conductance-based currents, the other with drift-diffusion currents, undergo transitions into and out of repetitive oscillations through different mechanisms and for different levels of stimulation. These differences in excitability are observed in response to excitatory synaptic input, and across different levels of ion channel expression. In general, the electrophysiological profiles of membranes modeled with drift-diffusion and conductance-based models having identical ion channel populations are different, potentially causing the input-output and computational properties of networks constructed with these models to be different as well. The drift-diffusion formulation is thus proposed as a theoretical improvement over conductance-based models that may lead to more accurate predictions and interpretations of experimental data at the single cell and network levels
Sensitivity of Asian Summer Monsoon precipitation to tropical sea surface temperature anomalies
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