Distributed Energy Resources: New Markets and New Products

The rapid introduction of Distributed Energy Resources (DER) into the retail/distribution sector of the electric power system has raised questions concerning both the economics and control of the power system. This paper presents one market paradigm that builds upon extension of the logic of Locational Marginal Pricing into the distribution level arguing that this extension is necessary if there are to be competitive forces that bring new technologies to market while at the same time assuring the reliability of service. We introduce three concepts: first that there are only three core products (real power, reactive power and reserves) and that all other products are combinations of these; second that it is necessary to calculate Distributed Locational Marginal Prices (DLMP) in order to value any DER; and third that for there to be a market for DER it should be structured as an economic platform

A nomenclature for restriction enzymes, DNA methyltransferases, homing endonucleases and their genes

A nomenclature is described for restriction endonucleases, DNA methyltransferases, homing endonucleases and related genes and gene products. It provides explicit categories for the many different Type II enzymes now identified and provides a system for naming the putative genes found by sequence analysis of microbial genome

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

Radioligand binding analyses of the group III metabotropic glutamate receptors

grantor: University of TorontoMy goal was to establish a baseline pharmacological profile for the group III mGluRs and to investigate differences in binding which may be present between the individual receptors. Of the four group III mGluRs, mGluR4 and mGluR8 displayed a high level of specific binding of [3H]-L-AP4, while no specific binding was detected for mGluR6 and mGluR7. [3H]-L-AP4 binding analyses were therefore performed for the mGluR4 and mGluR8 receptors. Results from competition experiments revealed that mGluR8 exhibited significantly higher binding affinities for group III-specific antagonists and the agonist PPG, compared to mGluR4. To investigate the basis for these binding differences, a combination of site-directed mutagenesis and molecular modeling was used to probe the ligand binding pockets of mGluR4 and mGluR8. Sequence similarity between the leucine-isoleucine-valine binding protein (LIVBP) and the mGluRs was used to model the ligand binding domain of mGluR4. Site-directed mutagenesis was used to substitute the serine 157 and glycine 158 residues of mGluR4 for their corresponding alanine residues in mGluR8. These substitutions created the mGluR4-S157A, G158A and S157A/G158A mutant receptors. (Abstract shortened by UMI.)M.Sc

Comparisons of isolates of the take-all fungus, Gaeumannomyces graminis var. tritici, from different cereal sequences using DNA probes and non-molecular methods

A mitochondrial ribosomal DNA probe (pEG34) that distinguishes two main restriction fragment length polymorphism (RFLP) types of isolate of the take-all fungus Gaeumannomyces graminis var. tritici was used to compare isolates from different host species. RFLP analysis confirmed that one type (designated T2), unlike the other type (T1), was associated more with barley than with triticale or wheat. RFLP analysis and other methods were also used to compare isolates of the take-all fungus from wheat seedlings grown in soil from first and second wheat crops. from wheat crops grown in longer sequences, and from oat crops grown as breaks from susceptible cereals. These provided samples from different stages of disease build up and decline in the take-all epidemic. Differences in frequencies of some characteristics were found at conventional significance levels (P less than or equal to 0.05): in a cereal sequence experiment at Rothamsted, U.K., isolates containing dsRNA were less frequent in T2 isolates than T1 isolates except in second wheats; perithecia were produced more abundantly on roots of wheat seedlings inoculated with T1 isolates than with T2 isolates, regardless of their origin. A weaker association (P less than or equal to 0.1) was also found: T2 isolates were often more frequent from second wheat crops, before take-all peaked in wheat sequences, than from other wheat crops or oats break crops. Collectively, the findings add only modest support to the controversial hypothesis that changes in the population of the take-all fungus occur during repeated cropping of wheat. The limitations of traditional sampling and assessment methods in such studies are discussed. (C) 1997 Elsevier Science Ltd.Peer reviewe

The DNA recognition subunit of a DNA methyltransferase is predominantly a molten globule in the absence of DNA

AbstractEnzyme-catalysed DNA methylation provides an opportunity for the modulation of protein-DNA recognition in biological systems. Recently we have demonstrated that the smaller of the two subunits of the heterodimeric, cytosine-specific DNA methyltransferase, M.AquI, is largely responsible for sequence-specific DNA recognition. Here we present evidence from a series of NMR, fluorescence and circular dichroism spectroscopy experiments that the DNA binding subunit of M.AquI has the characteristics of a molten globule in the absence of the catalytic machinery. In this metastable state this subunit retains its ability to bind DNA in a sequence-specific manner. We believe this finding offers an insight into the structural flexibility which underpins the mechansim of action of these enzymes, and may provide a possible biological role for molten globules in protein function