bluuebunny/crossref_metadata_2025 huggingface dataset:
Short article: Management of ruptured hepatocellular carcinoma in a European tertiary care center
Authors: Rijckborst Vincent , ter Borg Martijn J. , Tjwa Eric T. , Sprengers Dave , Verhoef Kees , Moelker Adriaan , Ijzermans Jan N. , de Man Robert A.
Published: April 2016

Goals and background

Spontaneous rupture is a rare complication of hepatocellular carcinoma (HCC). Treatment options consist of transcatheter arterial embolization (TAE), hepatic resection, and conservative therapy. The best approach is under debate.

Study

This study presents a review of clinical data of patients with a ruptured HCC admitted to a European tertiary care center.

Results

Eleven patients were included; six (55%) had underlying cirrhosis. The majority of patients (73%) had no previous history of HCC. Spontaneous HCC rupture was diagnosed using abdominal computed tomography with or without a diagnostic paracentesis. Computed tomography showed one or two tumors in eight (73%) patients; the other patients had multiple tumors or diffuse infiltrative HCC. Seven (64%) patients were initially treated by TAE and one (9%) patient underwent hepatic resection. The remaining three (27%) patients, all of whom had liver cirrhosis, received conservative therapy. Two patients initially treated by TAE underwent a delayed resection and ultimately received systemic therapy. Overall, at the end of the follow-up period, three patients were still alive at 84, 991, and 1026 days after the initial presentation. Eight (73%) patients had died after a median of 88 days (range 7–417). One year after presentation, none of the conservatively treated patients was alive compared with three out of seven (43%) patients treated with TAE with or without delayed resection.

Conclusion

Patients with a spontaneously ruptured HCC have a poor prognosis. In selected patients, however, prolonged survival is possible using TAE as initial therapy with or without a delayed resection and systemic therapy.
Effect of a Pragmatic, Cluster-randomized Controlled Trial on Patient Experience With Care
Authors: Dorr David A. , Anastas Tracy , Ramsey Katrina , Wagner Jesse , Sachdeva Bhavaya , Michaels LeAnn , Fagnan Lyle J.
Published: April 2016

Background:

Health reform programs like the patient-centered medical home are intended to improve the triple aim. Previous studies on patient-centered medical homes have shown mixed effects, but high value elements (HVEs) are expected to improve the triple aim.

Objective:

The aim of this study is to understand whether focusing on HVEs would improve patient experience with care.

Methods:

Eight clinics were cluster-randomized in a year-long trial. Both arms received practice facilitation, IT-based reporting, and financial incentives. Intervention practices were encouraged to choose HVEs for quality improvement goals. To assess patient experience, 1597 Consumer Assessment of Healthcare Providers and Systems surveys were sent pretrial and posttrial to a stratified random sample of patients. Difference-in-difference multivariate analysis was used to compare patient responses from intervention and control practices, adjusting for confounders.

Results:

The response rate was 43% (n=686). Nonrespondent analysis showed no difference between arms, although differences were seen by risk status and age. The overall difference in difference was 2.8%, favoring the intervention. The intervention performed better in 9 of 11 composites. The intervention performed significantly better in follow-up on test results (P=0.091) and patients’ rating of the provider (P=0.091), whereas the control performed better in access to care (P=0.093). Both arms also had decreases, including 4 of 11 composites for the intervention, and 8 of 11 for the control.

Discussion:

Practices that targeted HVEs showed significantly more improvement in patient experience of care. However, contemporaneous trends may have affected results, leading to declines in patient experience in both arms.
Refractory Mononeuritis Multiplex Due to Hepatitis C Infection and Cryoglobulinemia
Authors: Soares Cristiane N.
Published: April 2016

Background:

Mononeuritis multiplex due to hepatitis C infection and cryoglobulinemia has no specific treatment guidelines. Despite the favorable evolution of the liver disease after treatment with interferon and ribavirin, neurological symptoms might not respond very efficiently to antiviral therapy.

Case Report:

We report the case of a 50-year-old woman, with a mononeuritis multiplex related to cryoglobulinemia and hepatitis C virus infection, who was treated with rituximab. Hepatitis C virus infection was treated successfully with interferon-α and ribavirin, but the neurological symptoms were still worsening until rituximab therapy. Significant improvement of paraparesis and painful hypoesthesia were evident after the fourth infusion of rituximab. However, every 6 months, the neurological symptoms relapsed and the patient was subjected to a new cycle of rituximab therapy, with the disappearing of the paraparesis and hypoesthesias.

Conclusions:

This case highlights the potential use of rituximab in immune-mediated neuropathies, especially the mononeuritis multiplex associated with hepatitis C infection.
Caring for Patients With Functional Neurological Disorders
Authors: O’Neal Mary A. , Dworetzky Barbara A.
Published: April 2016

Patients with functional neurological symptoms are commonly seen in neurological practice. They have significant disability that may not improve and their care is costly. This article will use case histories to underline the important aspects of caring for patients with functional neurological disorders, including important features of the history, examination, neurobiology, appropriate investigations, and an approach to treatment.
The meaning of functional trait composition of food webs for ecosystem functioning
Authors: Gravel Dominique , Albouy Camille , Thuiller Wilfried
Published: April 2016

There is a growing interest in using trait-based approaches to characterize the functional structure of animal communities. Quantitative methods have been derived mostly for plant ecology, but it is now common to characterize the functional composition of various systems such as soils, coral reefs, pelagic food webs or terrestrial vertebrate communities. With the ever-increasing availability of distribution and trait data, a quantitative method to represent the different roles of animals in a community promise to find generalities that will facilitate cross-system comparisons. There is, however, currently no theory relating the functional composition of food webs to their dynamics and properties. The intuitive interpretation that more functional diversity leads to higher resource exploitation and better ecosystem functioning was brought from plant ecology and does not apply readily to food webs. Here we appraise whether there are interpretable metrics to describe the functional composition of food webs that could foster a better understanding of their structure and functioning. We first distinguish the various roles that traits have on food web topology, resource extraction (bottom-up effects), trophic regulation (top-down effects), and the ability to keep energy and materials within the community. We then discuss positive effects of functional trait diversity on food webs, such as niche construction and bottom-up effects. We follow with a discussion on the negative effects of functional diversity, such as enhanced competition (both exploitation and apparent) and top-down control. Our review reveals that most of our current understanding of the impact of functional trait diversity on food web properties and functioning comes from an over-simplistic representation of network structure with well-defined levels. We, therefore, conclude with propositions for new research avenues for both theoreticians and empiricists.
Locally rare species influence grassland ecosystem multifunctionality
Authors: Soliveres Santiago , Manning Peter , Prati Daniel , Gossner Martin M. , Alt Fabian , Arndt Hartmut , Baumgartner Vanessa , Binkenstein Julia , Birkhofer Klaus , Blaser Stefan , Blüthgen Nico , Boch Steffen , Böhm Stefan , Börschig Carmen , Buscot Francois , Diekötter Tim , Heinze Johannes , Hölzel Norbert , Jung Kirsten , Klaus Valentin H. , Klein Alexandra-Maria , Kleinebecker Till , Klemmer Sandra , Krauss Jochen , Lange Markus , Morris E. Kathryn , Müller Jörg , Oelmann Yvonne , Overmann Jörg , Pašalić Esther , Renner Swen C. , Rillig Matthias C. , Schaefer H. Martin , Schloter Michael , Schmitt Barbara , Schöning Ingo , Schrumpf Marion , Sikorski Johannes , Socher Stephanie A. , Solly Emily F. , Sonnemann Ilja , Sorkau Elisabeth , Steckel Juliane , Steffan-Dewenter Ingolf , Stempfhuber Barbara , Tschapka Marco , Türke Manfred , Venter Paul , Weiner Christiane N. , Weisser Wolfgang W. , Werner Michael , Westphal Catrin , Wilcke Wolfgang , Wolters Volkmar , Wubet Tesfaye , Wurst Susanne , Fischer Markus , Allan Eric
Published: April 2016

Species diversity promotes the delivery of multiple ecosystem functions (multifunctionality). However, the relative functional importance of rare and common species in driving the biodiversity–multifunctionality relationship remains unknown. We studied the relationship between the diversity of rare and common species (according to their local abundances and across nine different trophic groups), and multifunctionality indices derived from 14 ecosystem functions on 150 grasslands across a land-use intensity (LUI) gradient. The diversity of above- and below-ground rare species had opposite effects, with rare above-ground species being associated with high levels of multifunctionality, probably because their effects on different functions did not trade off against each other. Conversely, common species were only related to average, not high, levels of multifunctionality, and their functional effects declined with LUI. Apart from the community-level effects of diversity, we found significant positive associations between the abundance of individual species and multifunctionality in 6% of the species tested. Species-specific functional effects were best predicted by their response to LUI: species that declined in abundance with land use intensification were those associated with higher levels of multifunctionality. Our results highlight the importance of rare species for ecosystem multifunctionality and help guiding future conservation priorities.
Unifying ecological stoichiometry and metabolic theory to predict production and trophic transfer in a marine planktonic food web
Authors: Moorthi Stefanie D. , Schmitt Jennifer A. , Ryabov Alexey , Tsakalakis Ioannis , Blasius Bernd , Prelle Lara , Tiedemann Marc , Hodapp Dorothee
Published: April 2016

Two ecological frameworks have been used to explain multitrophic interactions, but rarely in combination: (i) ecological stoichiometry (ES), explaining consumption rates in response to consumers' demand and prey's nutrient content; and (ii) metabolic theory of ecology (MTE), proposing that temperature and body mass affect metabolic rates, growth and consumption rates. Here we combined both, ES and MTE to investigate interactive effects of phytoplankton prey stoichiometry, temperature and zooplankton consumer body mass on consumer grazing rates and production in a microcosm experiment. A simple model integrating parameters from both frameworks was used to predict interactive effects of temperature and nutrient conditions on consumer performance. Overall, model predictions reflected experimental patterns well: consumer grazing rates and production increased with temperature, as could be expected based on MTE. With decreasing algal food quality, grazing rates increased due to compensatory feeding, while consumer growth rates and final biovolume decreased. Nutrient effects on consumer biovolume increased with increasing temperature, while nutrient effects on grazing rates decreased. Highly interactive effects of temperature and nutrient supply indicate that combining the frameworks of ES and MTE is highly important to enhance our ability to predict ecosystem functioning in the context of global change.
The more things change, the more they stay the same? When is trait variability important for stability of ecosystem function in a changing environment
Authors: Wright Justin P. , Ames Gregory M. , Mitchell Rachel M.
Published: April 2016

The importance of intraspecific trait variability for community dynamics and ecosystem functioning has been underappreciated. There are theoretical reasons for predicting that species that differ in intraspecific trait variability will also differ in their effects on ecosystem functioning, particularly in variable environments. We discuss whether species with greater trait variability are likely to exhibit greater temporal stability in their population dynamics, and under which conditions this might lead to stability in ecosystem functioning. Resolving this requires us to consider several questions. First, are species with high levels of variation for one trait equally variable in others? In particular, is variability in response and effects traits typically correlated? Second, what is the relative contribution of local adaptation and phenotypic plasticity to trait variability? If local adaptation dominates, then stability in function requires one of two conditions: (i) individuals of appropriate phenotypes present in the environment at high enough frequencies to allow for populations to respond rapidly to the changing environment, and (ii) high levels of dispersal and gene flow. While we currently lack sufficient information on the causes and distribution of variability in functional traits, filling in these key data gaps should increase our ability to predict how changing biodiversity will alter ecosystem functioning.
Species richness and biomass explain spatial turnover in ecosystem functioning across tropical and temperate ecosystems
Authors: Barnes Andrew D. , Weigelt Patrick , Jochum Malte , Ott David , Hodapp Dorothee , Haneda Noor Farikhah , Brose Ulrich
Published: April 2016

Predicting ecosystem functioning at large spatial scales rests on our ability to scale up from local plots to landscapes, but this is highly contingent on our understanding of how functioning varies through space. Such an understanding has been hampered by a strong experimental focus of biodiversity–ecosystem functioning research restricted to small spatial scales. To address this limitation, we investigate the drivers of spatial variation in multitrophic energy flux—a measure of ecosystem functioning in complex communities—at the landscape scale. We use a structural equation modelling framework based on distance matrices to test how spatial and environmental distances drive variation in community energy flux via four mechanisms: species composition, species richness, niche complementarity and biomass. We found that in both a tropical and a temperate study region, geographical and environmental distance indirectly influence species richness and biomass, with clear evidence that these are the dominant mechanisms explaining variability in community energy flux over spatial and environmental gradients. Our results reveal that species composition and trait variability may become redundant in predicting ecosystem functioning at the landscape scale. Instead, we demonstrate that species richness and total biomass may best predict rates of ecosystem functioning at larger spatial scales.
Biodiversity and ecosystem functioning in evolving food webs
Authors: Allhoff K. T. , Drossel B.
Published: April 2016

We use computer simulations in order to study the interplay between biodiversity and ecosystem functioning (BEF) during both the formation and the ongoing evolution of large food webs. A species in our model is characterized by its own body mass, its preferred prey body mass and the width of its potential prey body mass spectrum. On an ecological time scale, population dynamics determines which species are viable and which ones go extinct. On an evolutionary time scale, new species emerge as modifications of existing ones. The network structure thus emerges and evolves in a self-organized manner. We analyse the relation between functional diversity and five community level measures of ecosystem functioning. These are the metabolic loss of the predator community, the total biomasses of the basal and the predator community, and the consumption rates on the basal community and within the predator community. Clear BEF relations are observed during the initial build-up of the networks, or when parameters are varied, causing bottom-up or top-down effects. However, ecosystem functioning measures fluctuate only very little during long-term evolution under constant environmental conditions, despite changes in functional diversity. This result supports the hypothesis that trophic cascades are weaker in more complex food webs.
Biodiversity–ecosystem functioning relationships in long-term time series and palaeoecological records: deep sea as a test bed
Authors: Yasuhara Moriaki , Doi Hideyuki , Wei Chih-Lin , Danovaro Roberto , Myhre Sarah E.
Published: April 2016

The link between biodiversity and ecosystem functioning (BEF) over long temporal scales is poorly understood. Here, we investigate biological monitoring and palaeoecological records on decadal, centennial and millennial time scales from a BEF framework by using deep sea, soft-sediment environments as a test bed. Results generally show positive BEF relationships, in agreement with BEF studies based on present-day spatial analyses and short-term manipulative experiments. However, the deep-sea BEF relationship is much noisier across longer time scales compared with modern observational studies. We also demonstrate with palaeoecological time-series data that a larger species pool does not enhance ecosystem stability through time, whereas higher abundance as an indicator of higher ecosystem functioning may enhance ecosystem stability. These results suggest that BEF relationships are potentially time scale-dependent. Environmental impacts on biodiversity and ecosystem functioning may be much stronger than biodiversity impacts on ecosystem functioning at long, decadal–millennial, time scales. Longer time scale perspectives, including palaeoecological and ecosystem monitoring data, are critical for predicting future BEF relationships on a rapidly changing planet.
Biogeochemical significance of pelagic ecosystem function: an end-Cretaceous case study
Authors: Henehan Michael J. , Hull Pincelli M. , Penman Donald E. , Rae James W. B. , Schmidt Daniela N.
Published: April 2016

Pelagic ecosystem function is integral to global biogeochemical cycling, and plays a major role in modulating atmospheric CO
2
concentrations (
p
CO
2
). Uncertainty as to the effects of human activities on marine ecosystem function hinders projection of future atmospheric
p
CO
2
. To this end, events in the geological past can provide informative case studies in the response of ecosystem function to environmental and ecological changes. Around the Cretaceous–Palaeogene (K–Pg) boundary, two such events occurred: Deccan large igneous province (LIP) eruptions and massive bolide impact at the Yucatan Peninsula. Both perturbed the environment, but only the impact coincided with marine mass extinction. As such, we use these events to directly contrast the response of marine biogeochemical cycling to environmental perturbation with and without changes in global species richness. We measure this biogeochemical response using records of deep-sea carbonate preservation. We find that Late Cretaceous Deccan volcanism prompted transient deep-sea carbonate dissolution of a larger magnitude and timescale than predicted by geochemical models. Even so, the effect of volcanism on carbonate preservation was slight compared with bolide impact. Empirical records and geochemical models support a pronounced increase in carbonate saturation state for more than 500 000 years following the mass extinction of pelagic carbonate producers at the K–Pg boundary. These examples highlight the importance of pelagic ecosystems in moderating climate and ocean chemistry.
Transcriptomic analysis of staphylococcal sRNAs: insights into species-specific adaption and the evolution of pathogenesis
Authors: Broach William H. , Weiss Andy , Shaw Lindsey N.
Published: April 2016

Next-generation sequencing technologies have dramatically increased the rate at which new genomes are sequenced. Accordingly, automated annotation programs have become adept at identifying and annotating protein coding regions, as well as common and conserved RNAs. Additionally, RNAseq techniques have advanced our ability to identify and annotate regulatory RNAs (sRNAs), which remain significantly understudied. Recently, our group catalogued and annotated all previously known and newly identified sRNAs in several Staphylococcus aureus strains. These complete annotation files now serve as tools to compare the sRNA content of S. aureus with other bacterial strains to investigate the conservation of their sRNomes. Accordingly, in this study we performed RNAseq on two staphylococcal species, Staphylococcus epidermidis and Staphylococcus carnosus, identifying 118 and 89 sRNAs in these organisms, respectively. The sRNA contents of all three species were then compared to elucidate their common and species-specific sRNA content, identifying a core set of between 53 and 36 sRNAs encoded in each organism. In addition, we determined that S. aureus has the largest set of unique sRNAs (137) while S. epidermidishas the fewest (25). Finally, we identify a highly conserved sequence and structural motif differentially represented within, yet common to, both S. aureus and S. epidermidis. Collectively, in this study, we uncover the sRNome common to three staphylococcal species, shedding light on sRNAs that are likely to be involved in basic physiological processes common to the genus. More significantly, we have identified species-specific sRNAs that are likely to influence the individual lifestyle and behaviour of these diverse staphylococcal strains.
Population Genetic Analysis of the DARC Locus (Duffy) Reveals Adaptation from Standing Variation Associated with Malaria Resistance in Humans
Authors: McManus Kimberly F. , Taravella Angela , Henn Brenna , Bustamante Carlos D. , Sikora Martin , Cornejo Omar E.
Published: April 2016

The human DARC (Duffy antigen receptor for chemokines) gene encodes a membrane-bound chemokine receptor crucial for the infection of red blood cells byPlasmodium vivax, a major causative agent of malaria. Of the three major allelic classes segregating in human populations, the FY*O allele has been shown to protect againstP. vivaxinfection and is near fixation in sub-Saharan Africa, while FY*B and FY*A are common in Europe and Asia, respectively. Due to the combination of its strong geographic differentiation and association with malaria resistance, DARC is considered a canonical example of a locus under positive selection in humans.

Here, we use sequencing data from over 1,000 individuals in twenty-one human populations, as well as ancient human and great ape genomes, to analyze the fine scale population structure of DARC. We estimate the time to most recent common ancestor (TMRCA) of the FY*O mutation to be 42 kya (95% CI: 34–49 kya). We infer the FY*O null mutation swept to fixation in Africa from standing variation with very low initial frequency (0.1%) and a selection coefficient of 0.043 (95% CI:0.011–0.18), which is among the strongest estimated in the genome. We estimate the TMRCAof the FY*A mutation to be 57 kya (95% CI: 48–65 kya) and infer that, prior to the sweep of FY*O, all three alleles were segregating in Africa, as highly diverged populations from Asia and ≠Khomani San hunter-gatherers share the same FY*A haplotypes. We test multiple models of admixture that may account for this observation and reject recent Asian or European admixture as the cause.

Author Summary

Infectious diseases have undoubtedly played an important role in ancient and modern human history. Yet, there are relatively few regions of the genome involved in resistance to pathogens that have shown a strong selection signal. We revisit the evolutionary history of a gene associated with resistance to the most common malaria-causing parasite,Plasmodium vivax, and show that it is one of regions of the human genome that has been under strongest selective pressure in our evolutionary history (selection coefficient: 5%). Our results are consistent with a complex evolutionary history of the locus involving selection on a mutation that was at a very low frequency in the ancestral African population (standing variation) and a large differentiation between European, Asian and African populations.
Integrated Biomedical System
Authors: Ricke Darrell O. , Harper James , Shcherbina Anna , Chiu Nelson
Published: April 2016

Capabilities for generating and storing large amounts of data relevant to individual health and performance are rapidly evolving and have the potential to accelerate progress toward quantitative and individualized understanding of many important issues in health and medicine. Recent advances in clinical and laboratory technologies provide increasingly complete and dynamic characterization of individual genomes, gene expression levels for genes, relative abundance of thousands of proteins, population levels for thousands of microbial species, quantitative imaging data, and more - all on the same individual. Personal and wearable electronic devices are increasingly enabling these same individuals to routinely and continuously capture vast amounts of quantitative data including activity, sleep, nutrition, environmental exposures, physiological signals, speech, and neurocognitive performance metrics at unprecedented temporal resolution and scales. While some of the companies offering these measurement technologies have begun to offer systems for integrating and displaying correlated individual data, these are either closed/proprietary platforms that provide limited access to sensor data or have limited scope that focus primarily on one data domain (e.g. steps/calories/activity, genetic data, etc.). The Integrated Biomedical System is being developed to demonstrate an adaptable open-source tool for reducing the burden associated with integrating heterogeneous genome, interactome, and exposome data from a constantly evolving landscape of biomedical data generating technologies. The Integrated Biomedical System provides a scalable and modular framework that can be extended to include support for numerous types of analyses and applications at scales ranging from personal users, communities and groups, to large populations.

Disclaimer

This work is sponsored by the Assistant Secretary of Defense for Research & Engineering under Air Force Contract #FA8721-05-C-0002. Opinions, interpretations, recommendations and conclusions are those of the author and are not necessarily endorsed by the United States Government.
Integration of Hormonal and Nutritional Cues Orchestrates Progressive Corolla Opening
Authors: Sun Chengzhen , Li Yanqiang , Zhao Wensheng , Song Xiaofei , Lu Man , Li Xiaoli , Li Xuexian , Liu Renyi , Yan Liying , Zhang Xiaolan
Published: April 2016

Flower opening is essential for pollination and thus successful sexual reproduction; however, the underlying mechanisms of its timing control remain largely elusive. We identify a unique cucumber (Cucumis sativus) line ‘6457’ that produces normal ovaries when nutrients are under-supplied, and super ovaries (87%) with delayed corolla opening when nutrients are oversupplied. Corolla opening in both normal and super ovaries is divided into four distinct phases, namely the green bud, green-yellow bud, yellow bud, and flowering stages, along with progressive color transition, cytological tuning, and differential expression of 14,282 genes. In the super ovary, cell division and cell expansion persisted for a significantly longer period of time; the expressions of genes related to photosynthesis, protein degradation, and signaling kinases were dramatically up-regulated, whereas the activities of most transcription factors and stress-related genes were significantly down-regulated; concentrations of cytokinins (CKs) and gibberellins were higher in accordance with reduced cytokinin conjugation and degradation and increased expression of gibberellin biosynthesis genes. Exogenous CK application was sufficient for the genesis of super ovaries, suggesting a decisive role of CKs in controlling the timing of corolla opening. Furthermore, 194 out of 11,127 differentially expressed genes identified in pairwise comparisons, including critical developmental, signaling, and cytological regulators, contained all three types of cis-elements for CK, nitrate, and phosphorus responses in their promoter regions, indicating that the integration of hormone modulation and nutritional regulation orchestrated the precise control of corolla opening in cucumber. Our findings provide a valuable framework for dissecting the regulatory pathways for flower opening in plants.
Crystal structure of bis(ethylenedithio)tetrathiafulvalenium μ2-acetato-bis[tribromidorhenate(III)] 1,1,2-trichloroethane hemisolvate
Authors: Golichenko Alexander A. , Kravchenko Andrey V. , Omelchenko Irina V. , Chudak Denis M. , Starodub Vladimir A. , Barszcz Boleslaw , Shtemenko Alexander V.
Published: April 2016

The asymmetric unit of the title salt, (C10H8S8)[Re2Br6(CH3COO)]·0.5C2H3Cl3, contains one bis(ethylenedithio)tetrathiafulvalene (ET) radical cation, one μ2-acetato-bis[tribromidorhenate(III)] anion and a 1,1,2-trichloroethane molecule with half-occupancy disordered about a twofold rotation axis. The tetrathiafulvalene fragment adopts an almost planar configuration typical of the ET radical cation. The C atoms of both ethylenedithio fragments in the cation are disordered over two orientations with occupancy factors 0.65:0.35 and 0.77:0.23. In the anion, six Br atoms and a μ2-acetate ligand form a strongly distorted cubic O2Br6coordination polyhedron around the Re2dinuclear centre. In the crystal, centrosymmetrically related ET cations and Re2O2Br6anions are linked into dimers by π–π stacking interactions [centroid-to-centroid distance = 3.826 (8) Å] and by pairs of additional Re...Br contacts [3.131 (3) Å], respectively. The dimers are further packed into a three-dimensional network by non-directional interionic electrostatic forces and by C—H...Br and C—H...S hydrogen bonds. The disordered 1,1,2-trichloroethane molecules occupy solvent-accessible channels along thebaxis.
Different N—H...π interactions in two indole derivatives
Authors: Kerr Jamie R. , Trembleau Laurent , Storey John M. D. , Wardell James L. , Harrison William T. A.
Published: April 2016

We describe the syntheses and crystal structures of two indole derivatives, namely 6-isopropyl-3-(2-nitro-1-phenylethyl)-1H-indole, C19H20N2O2, (I), and 2-(4-methoxyphenyl)-3-(2-nitro-1-phenylethyl)-1H-indole, C23H20N2O3, (II); the latter crystallizes with two molecules (AandB) with similar conformations (r.m.s. overlay fit = 0.139 Å) in the asymmetric unit. Despite the presence of O atoms as potential acceptors for classical hydrogen bonds, the dominant intermolecular interaction in each crystal is an N—H...π bond, which generates chains in (I) andA+AandB+Binversion dimers in (II). A different aromatic ring acts as the acceptor in each case. The packing is consolidated by C—H...π interactions in each case but aromatic π–π stacking interactions are absent.
Crystal structures ofEscherichia colibranching enzyme in complex with cyclodextrins
Authors: Feng Lei , Fawaz Remie , Hovde Stacy , Sheng Fang , Nosrati Meisam , Geiger James H.
Published: April 2016

Branching enzyme (BE) is responsible for the third step in glycogen/starch biosynthesis. It catalyzes the cleavage of α-1,4 glucan linkages and subsequent reattachment to form α-1,6 branch points. These branches are crucial to the final structure of glycogen and starch. The crystal structures ofEscherichia coliBE (EcBE) in complex with α-, β- and γ-cyclodextrin were determined in order to better understand substrate binding. Four cyclodextrin-binding sites were identified inEcBE; they were all located on the surface of the enzyme, with none in the vicinity of the active site. While three of the sites were also identified as linear polysaccharide-binding sites, one of the sites is specific for cyclodextrins. In previous work three additional binding sites were identified as exclusively binding linear malto-oligosaccharides. Comparison of the binding sites shed light on this apparent specificity. Binding site IV is located in the carbohydrate-binding module 48 (CBM48) domain ofEcBE and superimposes with the cyclodextrin-binding site found in the CBM48 domain of 5′-AMP-activated protein kinase (AMPK). Comparison of these sites shows the similarities and differences in the two binding modes. While some of the binding sites were found to be conserved between branching enzymes of different organisms, some are quite divergent, indicating both similarities and differences between oligosaccharide binding in branching enzymes from various sources.
Crystal structures of apo and inhibitor-bound TGFβR2 kinase domain: insights into TGFβR isoform selectivity
Authors: Tebben Andrew J. , Ruzanov Maxim , Gao Mian , Xie Dianlin , Kiefer Susan E. , Yan Chunhong , Newitt John A. , Zhang Liping , Kim Kyoung , Lu Hao , Kopcho Lisa M. , Sheriff Steven
Published: April 2016

The cytokine TGF-β modulates a number of cellular activities and plays a critical role in development, hemostasis and physiology, as well as in diseases including cancer and fibrosis. TGF-β signals through two transmembrane serine/threonine kinase receptors: TGFβR1 and TGFβR2. Multiple structures of the TGFβR1 kinase domain are known, but the structure of TGFβR2 remains unreported. Wild-type TGFβR2 kinase domain was refractory to crystallization, leading to the design of two mutated constructs: firstly, a TGFβR1 chimeric protein with seven ATP-site residues mutated to their counterparts in TGFβR2, and secondly, a reduction of surface entropy through mutation of six charged residues on the surface of the TGFβR2 kinase domain to alanines. These yielded apo and inhibitor-bound crystals that diffracted to high resolution (<2 Å). Comparison of these structures with those of TGFβR1 reveal shared ligand contacts as well as differences in the ATP-binding sites, suggesting strategies for the design of pan and selective TGFβR inhibitors.
Advanced DC-link voltage regulation of fuel-cell electric vehicle
Authors: Rajabzadeh Mahdi , Bathaee Seyed Mohammad Taghi , Golkar M. A.
Published: April 2016

Purpose

This paper investigates the DC-Link voltage regulation of fuel cell electric vehicle (FCEV) with hybrid power source (HPS). The HPS consists of fuel cell (FC) as the main source and ultracapacitor (UC) as the auxiliary source in order to compensate for the slow dynamics of FC in transient conditions. The system is a multiconverter structure which is comprised of a boost DC/DC converter and a buck-boost converter connecting FC and UC to DC-link respectively.

Design/methodology/approach

The FCEV is modeled dynamically, considering the nonlinear behavior of HPS and multiconverter system. This paper presents an advanced control approach based on the control Lyapunov function (CLF) to regulate the DC-link voltage and impeccable tracking of UC current to its references. The stability analysis of closed loop system is also insured.

Findings

The performance of proposed controller is illustrated via Simulink® using numerical simulations under European Extra Urban Driving Cycle (EUDC). The simulation results show that the presented method is both satisfactory and consistent with expectation.

Originality/value

The proposed control method is state of the art in FCEV and improves the energy management system.
Real-time simulation for performance evaluation of bidirectional quasi z-source inverter based medium voltage drives
Authors: Prasad H. , Maity T.
Published: April 2016

Purpose

Purpose – This paper presents the performance of medium voltage induction motor drive fed through a bidirectional quasi z-source inverter (BQ-ZSI). By controlling the shoot-through duty ratio, BQ-ZSI is able to produce desired stable ac output voltage even during the situation of critical power supply variation. BQ-ZSI based drive has unique properties like boosting the output voltage during voltage sag, reducing harmonic distortion and improving the input power factor. Generally, adjustable speed drives (ASD) are interrupted due to voltage sag in input supply that causes manufacturing and commercial losses. Replacing the conventional converter with BQ-ZSI, it can eliminate those common operational constraints.

Design/methodology/approach

This purpose is validated through simulations using real-time digital simulator (RTDS). RTDS is based on FPGA that interfaces the digital and analog I/O ports of the external hardware device. The IGBT based BQ-ZSI closed loop induction motor drive is modelled in SIMULINK and analysed through state space averaging technique. The suitable controllers are assigned and implemented on FPGA. The performance of the whole system is executed by offline simulation and analysed in hardware-in-loop (HIL) real time simulator with fixed-time step. HIL simulation plays important role in design and development stage for BQ-ZSI based medium voltage drives where virtual plant is executed instead of physical plant.

Findings

Real-time simulation results show the performance of 225KW, 3.3KV induction motor for BQ-ZSI based motor drive under both steady state and dynamic conditions. The applied closed loop control method provides nearly zero steady state speed error at any operating frequency.

Originality/value

The application of BQ-ZSI is explored for medium voltage drive to solve the issues of power supply quality through the design of suitable control solution. Performance results presented in this paper can help in development of simple and low cost prototype controller for the drive.
Optimized sensor and sensorless control of PMSM modeled in discrete mode: a comparison of KH and PSO algorithms
Authors: Younesi Aria , kazemi yousef , Moradpour Arman , Tohidi Sajjad
Published: April 2016

Purpose

The purpose of this paper is to improve dynamic performance of the permanent magnet synchronous motor (PMSM) field oriented control by means of optimizing its PI controller’s coefficients.

Design/methodology/approach

In this paper, Krill Herd (KH) optimization algorithm is proposed to optimize PI controller coefficients. Moreover, drive control system and steady state estimator are implemented in discrete mode. In order to evaluate the performance of the proposed algorithm, a comparison is carried out between KH and PSO algorithms. It is noteworthy that PSO algorithm has presented the best dynamic response among the studied approaches in literature.

Findings

By using the proposed optimization algorithm, the system tracks the reference speed with a very low error. In addition, the discrete mode simulations do not require initiating integrators. Moreover, it significantly increases the processing speed. The proposed approach is carried out in both sensor and sensorless drive systems. The simulation results indicate lower torque ripple, shorter settling time, lower overshoot, faster dynamic response and higher robustness against speed, torque and machine parameter changes.

Practical implications

The PI controller is extensively used in practical drive systems, due to its simple structure and implementation as well as its acceptable performance. On the other hand, PMSM benefits from high power density, high efficiency, low torque ripple, low inertia, and high performance in a wide speed range. This paper presents an efficient approach to optimize PI coefficients of the PMSM drive system.

Originality/value

This paper proposes a new algorithm (KH algorithm) to determine the coefficients of PI controllers in order to improve dynamic performance of the PMSM drive system.
A Hermite interpolation model for reconstructing the frequency spectrum of the lightning horizontal electric field
Authors: Zhang Boyuan , Zou Jun , Lee Jaebok , Mun-no Ju
Published: April 2016

Purpose

A fast algorithm is proposed to calculate the lightning horizontal electric field over a lossy ground.

Design/methodology/approach

The lightning horizontal electric field in frequency domain is approximated by a number of piecewise cubic polynomial functions by using the proposed adaptive Hermite strategy. To utilize the Hermite strategy, the frequency domain spectrum and its derivative with respect to frequency are required. The integral kernel of the derivative appears singular along the real axis. To overcome this singularity and accelerate the calculation, a new integration path is proposed. With the help of the Hermite interpolation model and the new path, the lightning horizontal electric field in time domain can be obtained rapidly.

Findings

The singularity problem has been overcome with the new integration path and the adaptive Hermite strategy proposed in this paper is at least 50 times faster than the one using the equally spaced sampling approach.

Originality/value

The adaptive Hermite approach can be a good candidate for fitting a wideband frequency domain response and the revised new integration path can be utilized when the calculation of the generalized Sommerfeld integral (GSI) or its derivative with respect to frequency is involved.
Frequency diverse array radar for target range-angle estimation
Authors: Huang Ling , Li Xiang , Gong Peng-Cheng , He Zhiming He
Published: April 2016

Purpose

Frequency diverse array (FDA) radar with uniform frequency offset between antenna elements has been proposed and investigated, which exhibits a range-angle-dependent beampattern. Nevertheless, because of the coupling in range and angle responses, it cannot estimate directly both the range and angle information of a target.The purpose of this paper is to consider a sub-array scheme of range-angle joint estimation of a target for frequency diverse array (FDA) radar.

Design/methodology/approach

First, The entire array is divided into two sub-arrays, which employs two different frequency offsets. For aperture extension, each sub-array adopts difference co-array structure . Therefore, the targets range and angle can be estimated directly with the subspace-based multiple signal classification algorithms for the decoupling capability of distance and angle dimensional. The estimation performance is examined by analyzing the Cramer-Rao lower bound (CRLB) versus signal-to-noise ratio (SNR).

Findings

Each sub-array adopts difference co-array structure to provide degrees of freedom by only physical sensors when the second-order statistics of the received data is used. And the sub-array is equivalent to two sets of equations to solve two unknown quantities, and the closed solution of the unknown quantity can be directly determined, which cannot be gained by the phase-array radar and basic ULA FDA radar. Finally, numerical simulation results verify the validity of the proposed method.

Originality/value

In this paper, we devise a subarray scheme on FDA radar for range and angle estimation. In order to aperture extension, difference co-array
is employed in each subarrays, and more targets can be distinguished than the physical sensors. The range and angle estimation performance is examined by analyzing the CRLB.
Shock filter based image super-resolution using dual-tree complex wavelet transform and singular value decomposition
Authors: gunnam suryanarayana , Dhuli Ravindra
Published: April 2016

Purpose

The purpose of this paper is to present an improved wavelet based approach in single image super resolution (SISR). The proposed method generates high resolution (HR) images by preserving the image contrast and edges simultaneously.

Design/methodology/approach

Covariance based interpolation algorithm is employed to obtain an initial estimate of the unknown HR image. The proposed method preserves the image contrast, by applying singular value decomposition (SVD) based correction on the dual-tree complex wavelet transform (DT-CWT) coefficients. In addition, the dual operating mode diffusion based shock filter (DBSF) ensures noise mitigation and edge preservation.

Findings

Experimental results on various test images reveal superiority of the proposed method over the existing SISR techniques in terms of peak signal to noise ratio (PSNR), structural similarity index measure (SSIM) and visual quality.

Originality/value

With SVD based correction, the proposed method preserves the image contrast and also the DBSF operation helps to achieve sharper edges.
Mono and bi-Level optimization architectures for powertrain design
Authors: Caillard Pierre , Gillon Frederic , Randi Sid-Ali , Janiaud Noelle
Published: April 2016

Purpose

The purpose of this paper is to compare two design optimization architectures for the optimal design of a complex device that integrates simultaneously the sizing of system components and the control strategy for increasing the energetic performances. The considered benchmark is a battery electric passenger car.

Design/methodology/approach

The optimal design of an electric vehicle powertrain is addressed within this paper, with regards to performances and range. The objectives and constraints require simulating several vehicle operating points, each of them has one degree of freedom for the electric machine control. This control is usually determined separately for each point with a sampling or an optimization loop resulting in an architecture called bi-level. In some conditions, the control variables can be transferred to the design optimization loop by suppressing the inner loop to get a mono-level formulation. The paper describes in which conditions this transformation can be done and compares the results for both architectures.

Findings

Results show a calculation time divided by more than 30 for the mono-level architecture compared to the natural bi-level on the study case. Even with the same models and optimization algorithms, the structure of the problem should be studied to improve the results, especially if computational cost is high.

Originality/value

The compared architectures bring new guidelines in the field optimal design for electric powertrains. The way to formulate a design optimization with some inner degrees of freedom can have a significant impact on computing time and on the problem understanding