bluuebunny/crossref_metadata_2025 huggingface dataset:
Ground‐penetrating Radar in the Regio III (Pompeii, Italy): Archaeological Evidence
Authors: Barone P. M. , Bellomo T. , Mattei E. , Lauro S. E. , Pettinelli E.
Published: April 2011

Ground‐penetrating radar (GPR) investigations were performed in Pompeii, in an area of the Regio III that is not yet fully excavated but is bounded by areas where much is known about the ancient Roman city. At the site studied, large areas containing preserved archaeological features are buried under as much as 8 m of volcanic deposits. The GPR survey was conducted using perpendicular reflection profiles in a grid adjacent to a scarp parallel to Nola Street, which allowed a direct correlation between the exposed ruins and the radar reflection features. An analysis of the GPR reflection profiles clearly shows the layering of the volcanic materials, with the underlying Roman architecture clearly differentiated. Amplitude analysis of all reflections within the grid produced spatial maps of the ruins containing a particular distribution of Roman elite buildings inside a Classic insula, including monumental fountains, apses and villas (domus); such architectural features were commonly incorporated into residences (villas) of wealthy people. Typically suburban districts of Roman cities contain non‐elite houses, whereas wealthy persons lived are in the city centre. However, in this case because these features are found away from the central district of Pompeii, it is possible to argue from the GPR analysis for the presence an elite off‐centre district possibly documenting suburban growth that reresents a newly wealthy society produced by the growing economy at the time of the eruption. The importance of collecting GPR reflection data in different directions was apparent in this study, as many of the architectural features of interest were visible in some profiles but not visible in others, depending on the orientation of the antenna dipolar field orientations. Copyright © 2011 John Wiley & Sons, Ltd.
Some properties of exact observability of linear stochastic systems and their applications
Authors: Hou Ting , Zhang Weihai , Ma Hongji
Published: April 2011

A new criterion is proposed for exact observability of linear stochastic systems. As applications of this criterion, the effects of exact observability due to state/output feedback are investigated. In addition, under the conditions of stability and exact observability, we discuss the properties of a set defined by the generalized Lyapunov equations (GLEs).

Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Black‐hole states in external galaxies
Authors: Belloni T.M.
Published: April 2011

A large number of Ultra‐Luminous X‐ray Sources in external galaxies is now known, but the discussion about their nature is still unsettled: intermediate‐mass black holes or stellar‐mass black holes accreting above the Eddington limit? A promising path that can provide an answer is through comparison with “normal” stellar‐mass black holes. These display separate states, identified from both their energy spectra and their fast variability. Although the nature of these states and their transitions is not clear, such a comparison can be extremely useful. In this paper, I briefly outline our current phenomenological knowledge of these states and present a (partial) overview of the different approaches followed to make these comparisons (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Six years of XMM‐Newton observations of NGC 1313 X‐1 and X‐2
Authors: Pintore F. , Zampieri L.
Published: April 2011

We present a systematic analysis of the X‐ray spectra of NGC 1313 X‐1 and NGC 1313 X‐2, using six years of XMM‐Newton observations (17 observations). We fitted the continuum with a Comptonization model plus a multicolor blackbody disc, that describes the effects of an accretion disc plus an optically thick corona. We checked the consistency of this spectral model on the basis of the variability patterns of its spectral parameters. We found that the two sources show different spectral states. We tentatively interpret the observed behaviour of NGC 1313 X‐1 within the framework of super‐Eddington accretion and that of NGC 1313 X‐2 within the framework of near Eddington accretion. We also attempted to determine the chemical abundances in the local environment of NGC 1313 X‐1 and X‐2, analyzing the RGS spectra of the longest observation available (122 ks). The results appear to indicate solar metallicity for the local environment of NGC 1313 X‐1 and sub‐solar metallicity for NGC 1313 X‐2 (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The demographics of ultraluminous X‐ray sources
Authors: Swartz D.A.
Published: April 2011

Results of recent statistical studies of the population of ultraluminous X‐ray sources are presented. Special emphasis is placed on the outcome of a complete survey of 140 nearby galaxies hosting 114 ULXs. It is shown that ULXs are preferentially associated with young star‐forming regions but not necessarily with massive young clusters, that ULXs occur at a higher rate (per unit mass) in dwarf galaxies compared to giant galaxies and that ULXs rarely occur in galactic halos. If an upper limit to the luminosity of ULXs exists, then it must be above several times 1040 erg s–1 in the X‐ray band. The luminosity function is still too sparsely sampled above this luminosity for a more definitive statement to be made (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Unlocking the nature of ultraluminous X‐ray sources using their X‐ray spectra
Authors: Gladstone J.C. , Roberts T.P. , Done C.
Published: April 2011

We explore the nature of ultraluminous X‐ray sources through detailed investigations of their spectral shape using some of the highest quality data available in the XMM‐Newton public archives. Phenomenological models allow us to characterise their spectra, while more ‘physically‐motivated’ models enable us to explore the physical processes underlying these characteristics. These physical models imply the presence of extreme (probably super‐Eddington) accretion on to stellar mass black holes (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The collective X‐ray luminosity of HMXB as a SFR indicator
Authors: Mineo S. , Gilfanov M. , Sunyaev R.
Published: April 2011

We study the relation between the X‐ray luminosity of compact sources and the SFR of the host galaxy. Our sample includes 38 galaxies for which a uniform set of X‐ray, infra‐red and ultraviolet data from Chandra, Spitzer and GALEX has been collected. Our primary goals are (i) to obtain a more accurate calibration of the Lx–SFR relation and (ii) to understand the origin of the dispersion in the Lx–SFR relation observed in previous studies. Preliminary results of this project are reported below (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Key results from an XMM‐Newton and Chandra study of a new sample of extreme ULXs from the 2XMM catalogue
Authors: Sutton A.D. , Roberts T.P. , Walton D.J.
Published: April 2011

We present highlights from a study of a sample of 10 extreme‐luminosity candidate ultraluminous X‐ray sources (Lx > 5 × 1040 erg s–1), all at distances <100 Mpc, identified from a cross‐correlation of the RC3 catalogue of galaxies with the 2XMM catalogue. Five of the sample have also been observed by Chandra. Of the 10 sources, seven reside in the disc or arms of spiral galaxies, and the remaining three are close to large elliptical galaxies. Unlike many less luminous ultraluminous X‐ray sources, temporal variability is observed on short (ks) and long (yr) timescales for most sources in our sample. Long term spectral variability is also evident in some sources. In one case, we use archival Chandra data to demonstrate that a hyperluminous X‐ray source candidate identified by XMM‐Newton is actually resolved into multiple point sources at high spatial resolution, but note that the other candidates remain unresolved under Chandra's intense scrutiny (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical variability of the ultraluminous X‐ray source NGC 1313 X‐2
Authors: Impiombato D. , Zampieri L. , Falomo R. , Grisé F. , Soria R.
Published: April 2011

We analyzed the longest phase‐connected photometric dataset available for NGC 1313 X‐2, looking for the ∼6 day modulation reported by Liu et al. (2009). The folded B ‐band light curve shows a 6 days periodicity with a significance slightly larger than 3σ. The low statistical significance of this modulation, along with the lack of detection in the V band, make its identification uncertain (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Compact radio emission in Ultraluminous X‐ray sources
Authors: Mezcua M. , Lobanov A.P.
Published: April 2011

We present results from our studies of radio emission from selected Ultraluminous X‐ray (ULX) sources, using archival Giant Metrewave Radio Telescope (GMRT) data and new European VLBI Network (EVN) observations. The GMRT data are used to find possible faint radio emission from ULX sources located in late‐type galaxies in the Chandra Deep Fields. No detections are found at 235, 325, and 610 MHz, and upper limits on the radio flux densities at these frequencies are given. The EVN observations target milliarcsecond‐scale structures in three ULXs with known radio counterparts (N4449‐X1, N4088‐X1, and N4861‐X2). We confirm an earlier identification of the ULX N4449‐X1 with a supernova remnant and obtain the most accurate estimates of its size and age. We detect compact radio emission for the ULX N4088‐X1, which could harbour an intermediate mass black hole (IMBH) of 105 M⊙ accreting at a sub‐Eddington rate. We detect a compact radio component in the ULX N4861‐X2, with a brightness temperature >106 K and an indication for possible extended emission. If the extended structure is confirmed, this ULX could be an H II region with a diameter of 8.6 pc and surface brightness temperature ≥105 K. The compact radio emission may be coming from a ∼105 M⊙ black hole accreting at 0.1 MEdd (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A search for radio counterparts to Chandra ULX candidates
Authors: Pérez‐Ramírez D. , Mezcua M. , Leon S. , Caballero‐García M.D.
Published: April 2011

We present a systematic search for radio counterparts to Ultraluminous X‐ray (ULX) source candidates based on a cross‐correlation of the Swartz et al. (2004) ULX catalogue based on Chandra data and the FIRST radio survey. We find seven cases of conspicuous peaks of radio emission that could be associated to ULX sources. Among these seven ULX radio candidates, three X‐ray sources are located within 5″of the FIRST radio peaks. These three cases are shown and discussed individually (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
(No) dynamical constraints on the mass of the black hole in two ULXs
Authors: Roberts T.P. , Gladstone J.C. , Goulding A.D. , Swinbank A.M. , Ward M.J. , Goad M.R. , Levan A.J.
Published: April 2011

We present the preliminary results of two Gemini campaigns to constrain the mass of the black hole in an ultraluminous X‐ray source (ULX) via optical spectroscopy. Pilot studies of the optical counterparts of a number of ULXs revealed two candidates for further detailed study, based on the presence of a broad He II 4686 Å emission line. A sequence of 10 long‐slit spectra were obtained for each object, and the velocity shift of the ULX counterpart measured. Although radial velocity variations are observed, they are not sinusoidal, and no mass function is obtained. However, the broad He II line is highly variable on timescales shorter than a day. If associated with the reprocessing of X‐rays in the accretion disc, its breadth implies that the disc must be close to face‐on (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Supercritical accretion and ULXs
Authors: Mineshige S. , Ohsuga K.
Published: April 2011

Supercritical (or super‐Eddington) accretion seems to occur in various black hole objects, including microquasars and ultra‐luminous X‐ray sources. We, here, elucidate the theory of supercritical accretion flow based on our two‐dimensional (2‐D) global radiation‐hydrodynamic (RHD) and radiation‐magnetohydrodynamic (RMHD) simulations. We first confirm that there is practically no limit to the accretion rate onto black holes. We then discuss several noteworthy observable features of the supercritical flow; that is, mild beaming, relativistic, collimated outflow, and inverse‐Compton scattering spectra by optically thick outflow. For face‐on observers the maximum apparent (isotropic) luminosities of ∼22LE (with L E being the Eddington luminosity) can be achieved for the mass supply rate of ∼50LE/c2. Even larger isotropic luminosities are possible for higher mass supply rates. For edge‐on observers, conversely, the apparent luminosity will be much less. It will be even lower, if the the innermost bright part of the disk is obscured by the outer part. High velocity (>0.5c) jet accelerated by radiation‐pressure force and collimated by Lorentz force is also expected. We expect large kinetic luminosity, ∼0.1LE, and high mass outflow rate, ∼10LE/c2. This may account for large ionizing nebulae around ULXs (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Forming massive black holes through stellar collapse: Observational diagnostics
Authors: Fryer C.L. , Heger A.
Published: April 2011

Massive black holes are believed to reside in the centers of many galaxies. Their seeds, 1000–100 000 solar mass black holes are believed to have formed during the first epoch of star formation. Observations of X‐ray binaries suggest that at least some intermediate mass black holes form at lower redshifts. If so, we may be able to observe these massive collapses. These collapses are very different than normal core‐collapse supernovae, however, and observing the collapse of massive stars will require different observing strategies than those used for normal stellar collapse. Unlike supernovae, the collapse of massive stars may not produce any burst of photons and we must be more creative in observing the occurrence of such exotic “outbursts”. Here we briefly review the observational prospects of massive star collapse, focusing on the ever‐present neutrino signal (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The black hole in NGC 1313 X‐2
Authors: Zampieri L. , Patruno A.
Published: April 2011

The amount of data available for NGC 1313 X‐2 make it a cornerstone for the study of ultraluminous X‐ray sources (ULXs). We modelled the optical and X‐ray data of this ULX with a binary evolution code that takes into account X‐ray irradiation. We restricted the candidate binary system to be either a 50–100 M⊙ black hole (BH) accreting from a 12–15 M⊙ main sequence star or a 20 M⊙ BH with a 12–15 M⊙ giant donor. If the orbital period of the system is ∼6 days, a 20 M⊙ BH model becomes unlikely and we are left with the only possibility that the compact accretor in NGC 1313 X‐2 is a massive BH of 50–100 M⊙. We briefly discuss these results within the framework of an alternative scenario for the formation ofULXs, in which a portion ofthem may contain BHs of ≳30–40 M⊙ formed from very massive stars in a low metallicity environment (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The use of demand correlation in the modeling of air carrier departure delays as first‐order autoregressive random processes
Authors: Mott John H.
Published: April 2011

A method for modeling air carrier departure delays at commercial‐service airports as autoregressive random processes is presented. This method employs the correlation of a priori demand data to significantly reduce prediction error in the optimal least‐squares estimator for additive white noise. The reduction factor of the prediction error is demonstrated to be on the order of 102 over that of the unbiased estimator. Copyright © 2011 John Wiley & Sons, Ltd.
Getting to the heart of planar cell polarity signaling
Authors: Henderson Deborah J. , Chaudhry Bill
Published: April 2011

The genes that underpin normal heart development, and which can be disrupted to result in congenital structural malformations, are rapidly being uncovered. However, the specific cellular processes that lie downstream of these genetic cascades, accurately shaping tissues and complex structures within the heart, remain relatively unclear. The noncanonical Wnt planar cell polarity (PCP) signaling pathway is known to have a role in embryonic morphogenesis and as such is an important candidate pathway to carry out these roles in heart development. The pathway regulates the polarization of cells in a variety of contexts, allowing cells to change shape and position and to “know” their orientation within a mass of tissue. PCP signaling has also been shown recently to regulate the cellular position of the primary cilium. This organelle is known to be crucial for the establishment of left‐right patterning in the early embryo and may also act as a signaling antenna for other developmental and regulatory pathways. It is not surprising that recent studies have also linked PCP to left‐right patterning. In this review, we will examine the current evidence suggesting that PCP signaling has a central role in cardiac development and malformation. Birth Defects Research (Part A) 2011. © 2011 Wiley‐Liss, Inc.
Xenopus: An emerging model for studying congenital heart disease
Authors: Kaltenbrun Erin , Tandon Panna , Amin Nirav M. , Waldron Lauren , Showell Chris , Conlon Frank L.
Published: April 2011

Congenital heart defects affect nearly 1% of all newborns and are a significant cause of infant death. Clinical studies have identified a number of congenital heart syndromes associated with mutations in genes that are involved in the complex process of cardiogenesis. The African clawed frog, Xenopus, has been instrumental in studies of vertebrate heart development and provides a valuable tool to investigate the molecular mechanisms underlying human congenital heart diseases. In this review, we discuss the methodologies that make Xenopus an ideal model system to investigate heart development and disease. We also outline congenital heart conditions linked to cardiac genes that have been well studied in Xenopus and describe some emerging technologies that will further aid in the study of these complex syndromes. Birth Defects Research (Part A), 2011. © 2011 Wiley‐Liss, Inc.
TGFβ signaling and congenital heart disease: Insights from mouse studies
Authors: Arthur Helen M. , Bamforth Simon D.
Published: April 2011

Transforming growth factor β (TGFβ) regulates one of the major signaling pathways that control tissue morphogenesis. In vitro experiments using heart explants indicated the importance of this signaling pathway for the generation of cushion mesenchymal cells, which ultimately contribute to the valves and septa of the mature heart. Recent advances in mouse genetics have enabled in vivo investigation into the roles of individual ligands, receptors, and coreceptors of this pathway, including investigation of the tissue specificity of these roles in heart development. This work has revealed that (1) cushion mesenchyme can form in the absence of TGFβ signaling, although mesenchymal cell numbers may be misregulated; (2) TGFβ signaling is essential for correct remodeling of the cushions, particularly those of the outflow tract; (3) TGFβ signaling also has a role in ensuring accurate remodeling of the pharyngeal arch arteries to form the mature aortic arch; and (4) mesenchymal cells derived from the epicardium require TGFβ signaling to promote their differentiation to vascular smooth muscle cells to support the coronary arteries. In addition, a mouse genetics approach has also been used to investigate the disease pathogenesis of Loeys‐Dietz syndrome, a familial autosomal dominant human disorder characterized by a dilated aortic root, and associated with mutations in the two TGFβ signaling receptor genes,TGFBR1andTGFBR2. Further important insights are likely as this exciting work progresses. Birth Defects Research (Part A), 2011.© 2011 Wiley‐Liss, Inc.
The emerging genetic landscape underlying cardiac conduction system function
Authors: Arnolds David E. , Chu Alison , McNally Elizabeth M. , Nobrega Marcelo A. , Moskowitz Ivan P.
Published: April 2011

Proper function of an organized Cardiac Conduction System (CCS) is vital to the survival of metazoans ranging from fly to man. The routine use of non‐invasive electrocardiogram measures in the diagnosis and monitoring of cardiovascular health has established a trove of reliable CCS functional data in both normal and diseased cardiac states. Recent combination of echocardiogram (ECG) data with genome‐wide association studies has identified genomic regions implicated in ECG variability which impact CCS function. In this study, we review the substantial recent progress in this area, highlighting the identification of novel loci, confirming the importance of previously implicated loci in CCS function, and exploring potential links between genes with important roles in developmental processes and variation in function of the CCS. Birth Defects Research (Part A), 2011. © 2011 Wiley‐Liss, Inc.
Metabolic self‐organization of bioluminescent Escherichia coli
Authors: Šimkus Remigijus , Baronas Romas
Published: April 2011

A possible reason for the complexity of the signals produced by bioluminescent biosensors might be self‐organization of the cells. In order to verify this possibility, bioluminescence images of cultures of lux gene reporter Escherichia coli were recorded for several hours after being placed into 8–10 mm diameter cylindrical containers. It was found that luminous cells distribute near the three‐phase contact line, forming irregular azimuthal waves. As we show, space–time plots of quasi‐one‐dimensional bioluminescence measured along the contact line can be simulated by reaction–diffusion–chemotaxis equations, in which the reaction term for the cells is a logistic (autocatalytic) growth function. It was found that the growth rate of the luminous cells (~0.02 s−1) is >100 times higher than the growth rate of E. coli. We provide an explanation for this result by assuming that E. coli exhibits considerable respiratory flexibility (the ability of oxygen‐induced switching from one metabolic pathway to another). According to the simple two‐state model presented here, the number of oxic (luminous) cells grows at the expense of anoxic (dark) cells, whereas the total number of (oxic and anoxic) cells remains unchanged. It is conjectured that the corresponding reaction–diffusion–chemotaxis model for bioluminescence pattern formation can be considered as a model for the energy‐taxis and metabolic self‐organization in the population of the metabolically flexible bacteria under hypoxic conditions. Copyright © 2011 John Wiley & Sons, Ltd.
Presidents page
Authors: Smith Linda C.
Published: April 2011

Editor's Summary

As ASIS&T president for 2011, Linda Smith is emphasizing the use of webinars to provide educational opportunities that support the Society's purpose of encouraging members' professional growth. A live, interactive, online presentation, a webinar serves well as an educational forum for participants and adds long‐term value through recording and archiving. Smith is leading efforts focusing on webinar content development, providers, delivery issues, costs and compensation, and policies to serve further development. A two‐part ASIS&T webinar on linked data follows multi‐part webinar presentations on information architecture and on taxonomy uses.
Introduction: Knowledge organization innovation: Design and frameworks
Authors: Greenberg Jane
Published: April 2011

Editor's Summary

The collection of articles in this issue of the Bulletin of the American Society for Information Science and Technology reflects the association between knowledge and the methods we use to represent a knowledge domain – knowledge organization systems (KOS). Though necessary and beneficial, our efforts to capture and represent knowledge impose a structure and inevitably reflect our perceptions and established notions. We must be aware of limits created in the process and be open to innovative approaches that facilitate access and serve all users without operational or cultural barriers. These collected articles explore new ideas in developing KOS designs and in their structural frameworks. They describe real world projects that illustrate innovations and challenge conventional approaches to knowledge organization systems.
A STELLAR role for knowledge organization systems in digital archaeology
Authors: Tudhope Douglas , Binding Ceri , Jeffrey Stuart , May Keith , Vlachidis Andreas
Published: April 2011

Editor's Summary

Research data in archaeology is being made more accessible through the semantic efforts of the STAR and STELLAR projects of two United Kingdom universities. The goal of STAR (Semantic Technologies for Archaeological Resources) is to facilitate semantic interoperability, enabling a structured semantic search of five databases and grey literature reports using an ontology of cultural heritage in combination with other knowledge organization systems. STAR employs natural language processing to identify key concepts and generate semantic metadata to support the unified search. STELLAR (Semantic Technologies Enhancing Links and Linked data for Archaeological Resources) takes the process a step further by simplifying the job of expressing excavation data in CRM ontology terms and then generating representations as linked data. The two projects demonstrate the effectiveness of semantic interoperability methods, coordinating data and vocabularies in a shared framework, and supporting the reuse of archaeological excavation data.
Developing an eclectic terminology registry
Authors: Hlava Marjorie
Published: April 2011

Editor's Summary

As taxonomies and other knowledge organization systems expand, the need for a shared space to collect and describe these terminologies is becoming more pressing. A solution is the TaxoBank Terminology Registry, sponsored by Access Innovations, Inc. TaxoBank borrows from a terminology registry metadata model developed in the United Kingdom, offering a set of metadata to describe a vocabulary, its major and minor topics, languages, conditions for use, provider and more. TaxoBank's coverage is broad, ranging from large and formal vocabularies from governmental entities to small and quirky thesauri submissions from library and information science students. The registry is a collaborative effort, welcoming all to contribute and describe a vocabulary, as well as to review, borrow and learn from other taxonomy submissions.
Using social discovery systems to leverage user‐generated metadata
Authors: Spiteri Louise F.
Published: April 2011

Editor's Summary

The use of social discovery systems is rapidly expanding, often building vibrant and interactive communities. Some public and academic libraries are trying out these systems, in which patrons can contribute ratings, reviews, and comments. While user‐contributed metadata may not equal the quality of professional cataloging, it can enhance the catalog records with rich supplementary information and personal perspectives. The author's examination of use of social features in two public libraries led to the discouraging observation that addition of user‐generated metadata in these contexts was limited, in sharp contrast to other social sites. The question of motivation is key. People's notions of library catalog records and their ownership by library staff may present an obstacle to contributing metadata. User‐generated metadata has the potential to add value to records while conserving limited library resources. The challenge of promoting the active use of social discovery systems in libraries demands further research.
Developing a Dublin Core Application Profile for the knowledge organization systems (KOS) resources
Authors: Zeng Marcia Lei , Hodge Gail
Published: April 2011

Editor's Summary

Since 2000, members of the Networked Knowledge Organization Systems/Services (NKOS) group have been working on specifications for metadata to describe the variety of knowledge organization systems (KOS), including classification schemes, thesauri and taxonomies. At the 2010 Dublin Core Metadata Initiative (DCMI) International Conference, a task group was formed to create a Dublin Core Application Profile (DCAP) for KOS to facilitate the use of KOS in networked settings. The DCAP details metadata used for a KOS application, addressing how the KOS is to function, the items and interrelationships described, the metadata terms used and their rules for use and the machine syntax used for encoding data. Building on past work, the task group is making progress toward its numerous goals, including production of a KOS Type Vocabulary, integrating the KOS taxonomy and KOS typology into a single workable product and ultimately testing the KOS DCAP and Typology on a variety of actual knowledge organization systems.
Idea Collider: From a theory of knowledge organization to a theory of knowledge interaction
Authors: Smiraglia Richard P. , van den Heuvel Charles
Published: April 2011

Editor's Summary

A new and novel addition to core concepts of information science and technology is the Idea Collider, adapting the conceptual basis of the particle accelerator. The Idea Collider is presented as a theory of information and an information retrieval tool that deconstructs text to the underlying elements – the concepts, ideas, knowledge entities, taxons and knowledge bases – and then reconstitutes groupings of data. The authors champion the idea of a “multiverse of knowledge,” in contrast to the “universe of knowledge” that is an important metaphor in traditional classification theory. A historical review of outstanding theoretical landmarks in classification theory explores the universe of knowledge metaphor, faceted classification theory and the universe of concepts, moving from a holistic view of existing knowledge to an elemental deconstruction that can account for all knowledge, past and future. The Idea Collider is proposed as a theoretical approach to identifying the essential parts of knowledge, dissociating those elements from culture‐ and time‐bound dimensions and making them available for a bottom‐up reassembly process.
Transport of Free and Peptide‐Bound Glycated Amino Acids: Synthesis, Transepithelial Flux at Caco‐2 Cell Monolayers, and Interaction with Apical Membrane Transport Proteins
Authors: Hellwig Michael , Geissler Stefanie , Matthes René , Peto Anett , Silow Christoph , Brandsch Matthias , Henle Thomas
Published: April 2011

In glycation reactions, the side chains of protein‐bound nucleophilic amino acids such as lysine and arginine are post‐translationally modified to a variety of derivatives also known as Maillard reaction products (MRPs). Considerable amounts of MRPs are taken up in food. Here we have studied the interactions of free and dipeptide‐bound MRPs with intestinal transport systems. Free and dipeptide‐bound derivatives of N6‐(1‐fructosyl)lysine (FL), N6‐(carboxymethyl)lysine (CML), N6‐(1‐carboxyethyl)lysine (CEL), formyline, argpyrimidine, and methylglyoxal‐derived hydroimidazolone 1 (MG‐H1) were synthesized. The inhibition of L‐[3H]lysine and [14C]glycylsarcosine uptakes was measured in Caco‐2 cells which express the H+/peptide transporter PEPT1 and lysine transport system(s). Glycated amino acids always displayed lower affinities than their unmodified analogues towards the L‐[3H]lysine transporter(s). In contrast, all glycated dipeptides except Ala‐FL were medium‐ to high‐affinity inhibitors of [14C]Gly‐Sar uptake. The transepithelial flux of the derivatives across Caco‐2 cell monolayers was determined. Free amino acids and intact peptides derived from CML and CEL were translocated to very small extents. Application of peptide‐bound MRPs, however, led to elevation (up to 80‐fold) of the net flux and intracellular accumulation of glycated amino acids, which were hydrolyzed from the dipeptides inside the cells. We conclude 1) that free MRPs are not substrates for the intestinal lysine transporter(s), and 2) that dietary MRPs are absorbed into intestinal cells in the form of dipeptides, most likely by the peptide transporter PEPT1. After hydrolysis, hydrophobic glycated amino acids such as pyrraline, formyline, maltosine, and argpyrimidine undergo basolateral efflux, most likely by simple diffusion down their concentration gradients.
Exploration of Biarsenical Chemistry—Challenges in Protein Research
Authors: Pomorski Adam , Krężel Artur
Published: April 2011

The fluorescent modification of proteins (with genetically encoded low‐molecular‐mass fluorophores, affinity probes, or other chemically active species) is extraordinarily useful for monitoring and controlling protein functions in vitro, as well as in cell cultures and tissues. The large sizes of some fluorescent tags, such as fluorescent proteins, often perturb normal activity and localization of the protein of interest, as well as other effects. Of the many fluorescent‐labeling strategies applied to in vitro and in vivo studies, one is very promising. This requires a very short (6‐ to12‐residue), appropriately spaced, tetracysteine sequence (CCXXCC); this is either placed at a protein terminus, within flexible loops, or incorporated into secondary structure elements. Proteins that contain the tetracysteine motif become highly fluorescent upon labeling with a nonluminescent biarsenical probe, and form very stable covalent complexes. We focus on the development, growth, and multiple applications of this protein research methodology, both in vitro and in vivo. Its application is not limited to intact‐cell protein visualization; it has tremendous potential in other protein research disciplines, such as protein purification and activity control, electron microscopy imaging of cells or tissue, protein–protein interaction studies, protein stability, and aggregation studies.
Perforation of the descending thoracic aorta during transcatheter aortic valve implantation (TAVI): An unexpected and dramatic procedural complication
Authors: Aminian Adel , Lalmand Jacques , El Nakadi Badih
Published: April 2011

Transcatheter aortic valve implantation (TAVI) has become an established technique for the treatment of aortic stenosis in patients who cannot undergo surgery. Although TAVI is obviously less invasive than open surgical repair, it is not free of complications. We report a case of unexplained refractory shock during transfemoral TAVI with subsequent autopsy demonstrating a 1‐cm large perforation of the descending thoracic aorta as the cause of death. To the best of our knowledge, this is the first case ever reported. © 2011 Wiley‐Liss, Inc.
Ischemic hepatitis secondary to hepatic artery steal in a patient with celiac artery stenosis and severe postural hypotension
Authors: Panwar Vikram , Ranaweera Priyantha
Published: April 2011

Ischemic hepatitis, also known as hypoxic hepatitis or shock liver is defined as an acute, transient elevation of aminotransferase levels in the absence of any known causes. The pathogenesis is multifactorial. Many studies have suggested systemic hypotension as a major contributor to the pathogenesis of ischemic hepatitis but that alone is not enough to cause it. Celiac artery stenosis does not commonly cause clinically significant hepatic ischemia because of its rich collaterals. We present a case of a 78‐year‐old male with a background of severe orthostatic hypotension, who presented with elevation of liver enzymes due to hepatic artery steal precipitated by celiac artery stenosis. Clinical investigations showed elevated transaminases and unremarkable CT scan. Invasive celiac artery angiography showed a critical ostial lesion and it was stented. The liver enzymes peaked the day following stenting and normalized over the next 9 days. This confirmed clinically significant hepatic artery steal due to an ostial celiac artery stenosis. Relieving the celiac artery stenosis normalized the liver enzymes confirming the interdependence of the two components of this rare syndrome. Our report is the only report to our knowledge where classic hepatic artery steal and shock liver was demonstrated due to the rare combination of severe orthostatic hypotension and celiac artery ostial stenosis. © 2011 Wiley‐Liss, Inc.
Vascular hemostasis bandage compared to standard manual compression after cardiac catheterization in children
Authors: Waragai Tadashi , Morgan Gareth , Ralston Tami , Chaturvedi Rajiv , Lee Kyong‐Jin , Benson Lee
Published: April 2011

Background: Femoral venous and arterial approaches are the commonly used to obtain vascular access for pediatric cardiac catheterization. Hemostasis after catheter removal is usually obtained by manual compression. However, this technique is time consuming and at times painful. Although several closure devices are available for adults, they are not widely applicable in children. Objectives: To evaluate the safety and efficacy of a microporous polysaccharide hemospheres hemostasis (MPH) bandage compared to manual compression. Methods: Prospective randomized study, involving 112 children after cardiac catheterization. One group received the MPH bandage, another manual compression. Compression time was predetermined by the size of sheath plus one minute. Success was defined as no bleeding or hematoma formation. If bleeding continued, compression was continued as needed and time to hemostasis recorded. Informed consent was obtained prior to randomization. Group comparisons were performed with a Student's t, Pearson's Chi Square, and Fisher's exact test as appropriate. Results: Fewer children required a compression time of >15 min (P = 0.006) and more had a shorter time to hemostasis (P = 0.003) in the MPH group for venous access control. Time to hemostasis was also shorter in the MPH (P = 0.048) in arterial access cases, but the number of children requiring a compression time >15 min was the same. Complications including hematoma formation in each group were similar. Conclusions: The MPH bandage allows a shorter time to achieve hemostasis compared to manual compression. This improves turnaround time and laboratory efficiency. © 2011 Wiley‐Liss, Inc.
Vascular interventions in young patients undergoing transvenous pacemaker revision
Authors: Zartner Peter , Toussaint‐Goetz Nicole , Wiebe Walter , Schneider Martin
Published: April 2011

Aims:

: Transvenous lead implantation for pacemaker (PM) or implantable cardioverter defibrillators systems in children and young patients with congenital heart disease is widely practiced. With longer implantation times, the risk for vascular occlusion increases. Transvenous angioplasty may be used to maintain venous patency for system revision in the future. Retrospective analysis of the interventional techniques employed in our young patients undergoing PM revision may identify its clinical benefit.

Methods and Results:

: Between May 2005 and August 2010, 28 procedures to maintain central venous patency were performed in 24 patients. Median age was 14.3 years (range, 3.6–29.5 years). The median lead age at time of intervention was 6.8 years (range, 8 days–21.5 years). Balloon dilation of the stenotic vessels was performed with and without prior lead removal. Revascularization with stent implantation was successfully attempted in all clinically relevant obstructions. All PM systems retained full function or were upgraded as planned. There were no major complications and acute surgical referral was not required.

Conclusion:

: Angioplasty techniques may be used to maintain and increase the longevity of transvenous pacing pathways in young patients. © 2011 Wiley Periodicals, Inc.
Early‐ and mid‐term outcomes of transcatheter aortic valve implantation in patients with logistic EuroSCORE less than 20%: A comparative analysis between different risk strata
Authors: Tamburino Corrado , Barbanti Marco , Capodanno Davide , Sarkar Kunal , Cammalleri Valeria , Scarabelli Marilena , Mulè Massimiliano , Immè Sebastiano , Aruta Patrizia , Ussia Gian Paolo
Published: April 2011

Background: Transcatheter Aortic Valve Implantation (TAVI) is an emerging alternative to medical therapy reserved to a limited population with severe aortic stenosis. The European consensus document recommended TAVI for prohibitive‐risk patients not eligible for conventional surgery (prohibitive risk defined as expected mortality ≥ 20% calculated with the Logistic EuroScore (LES) in association with clinical judgment). To date, there is lack of clarity on data about outcomes of TAVI in lower risk patients. We sought to evaluate the outcomes of patients undergoing TAVI with LES ≥ 20% in comparison with patients with LES < 20%.

Method: Of 165 patients who underwent TAVI using the 18‐French Medtronic CoreValve (N = 153) and the Sapien Edwards™ (N = 12) at our Institution between June 2007 and September 2010, we identified those with LES < 20%, with prosthesis implantation (n = 84), and reported on their clinical outcome compared with patients with LES ≥ 20% (n = 78). The primary endpoint was the incidence of overall death and major adverse cerebrovascular and cardiac events (MACCE) at 30‐day and midterm follow‐up stratifying patients by clinical characteristics.

Results: At 30‐day, a significant higher incidence of MACCE (20.8% vs. 6.0%, odds ratio [OR] 4.08 95% confidence interval [CI] 1.42–11.74, P = 0.009) and death (15.6% vs. 2.4%, OR 7.45 95% CI 1.61–34.48, P = 0.010) was reported in the LES ≥ 20% group as compared with the LES < 20% group, respectively. The 12‐month MACCE rates was (27.1% vs. 11.4%, hazard ratio [HR] 2.47 95% CI 0.93–6.63, P = 0. 071) for LES ≥ 20% and LES < 20% patients, respectively (mortality rates was 25.7% vs. 6.8% HR 4.21 95% CI 1.24–14.30, P = 0.021).

Conclusion: This study tends to suggest that current mortality reported after TAVI could be significantly affected by the very‐high risk profile of the population which currently undergoes this procedure, making comparison with surgical series rather unreliable. © 2011 Wiley Periodicals, Inc
Serial intravascular ultrasound analysis comparing double kissing and classical crush stenting for coronary bifurcation lesions
Authors: Chen Shao‐Liang , Mintz Gary , Kan Jing , Zhang Jun‐Jie , Hu Zuo‐Ying , Ye Fei , Tian Nai‐Liang , Zhang Jun‐Xia , Xu Tian , Liu Zhi‐Zhong
Published: April 2011

Background: Compared with the classical crush, double kissing (DK) crush improved outcomes in patients with coronary bifurcation lesions. However, there is no serial intravascular ultrasound (IVUS) comparisons between these two techniques. Objectives: This study aimed to analyze the mechanisms of the two crush stenting techniques using serial IVUS imaging. Methods: A total of 54 patients with IVUS images at baseline, post‐stenting and eight‐month follow‐up were classified into classical (n = 16) and DK (n = 38) groups. All patients underwent final kissing balloon inflation (FKBI). Unsatisfactory kissing (KUS) was defined as the presence of wrist or >20% stenosis during FKBI at the side branch (SB) ostium. The vessels at bifurcation lesions were divided into the proximal main vessel (MV) stent, the crushed segment, the distal MV stent, the SB ostium and the SB stent body. Results: KUS and incomplete crushing were commonly observed in the classical group (62.5%, 81.3%), compared with DK group (18.0%, 39.5%, P < 0.001 and P = 0.004). The post‐stenting stent symmetry in the classical group was 71.85 ± 7.69% relative to 85.93 ± 6.09% in DK group (P = 0.022), resulting in significant differences in neointimal hyperplasia (NIH, 1.60 ± 0.21 mm2 vs. 0.85 ± 0.23 mm2, P = 0.005), late lumen loss (1.31 ± 0.81 mm2 vs. 0.55 ± 0.70 mm2, P = 0.013), and minimal lumen area (MLA, 3.57 ± 1.52 mm2 vs. 4.52 ± 1.40 mm2,
P = 0.042) at the SB ostium between two groups. KUS was positively correlated with the incomplete crush and was the only predictor of in‐stent‐restenosis (ISR) at the SB ostium. Conclusion: DK crush was associated with improved quality of the FKBI and larger MLA. KUS predicted the occurrence of ISR. © 2011 Wiley Periodicals, Inc.
Transcatheter valve in valve implantation for failed mitral and tricuspid bioprosthesis
Authors: Cerillo Alfredo Giuseppe , Chiaramonti Francesca , Murzi Michele , Bevilacqua Stefano , Cerone Elisa , Palmieri Cataldo , Del Sarto Paolo , Mariani Massimiliano , Berti Sergio , Glauber Mattia
Published: April 2011

Objective: We report our experience with the transapical transcatheter “Valve in valve” implantation (T‐VIV) in patients with a failed mitral or tricuspid bioprosthesis; we briefly review the pertinent literature, and discuss some technical aspects of this procedure. Background: Redo valve surgery for failure of a mitral or tricuspid bioprosthesis might become extremely challenging, both because of the patients' condition, which is frequently poor, and for the technical aspects of the operation itself, that can be very demanding. T‐VIV has been widely employed with good results for the treatment of aortic bioprosthesis failure, and could represent an attractive option in this setting. Methods: Four patients with multiple comorbidities (age: 63‐83 years; logistic Euroscore: 37.2‐81.5) underwent T‐VIV at our institution for failure of a mitral [3] or tricuspid [1] bioprosthesis. A 26mm Sapien valve was used in all cases. All the mitral procedures were performed via a transapical approach. The tricuspid procedure was performed via a transjugular approach. Results: The first mitral procedure was complicated by the splaying of the xenograft stents and embolization of the valve. The procedure was converted to conventional surgery, and the patient died on postoperative day 1. In the subsequent procedures, the valve was positioned more atrially, and was fixed to the malfunctioning xenograft sewing ring. All subsequent procedures were successful, all patients were discharged home and were alive and well at follow‐up. Conclusions: The results of T‐VIV procedure in the mitral position have been suboptimal, and four of the sixteen patients reported to date died. However, all patients were extremely diseased, and some of the reported failures were related to amendable technical factors relative to the surgical access or to the valve deployment technique. With increasing experience, this procedure might become indicated as an alternative to conventional surgery in selected patients, encouraging increased use of bioprosthesis, and marking a pivotal change in the management of valvular disease. © 2011 Wiley Periodicals, Inc.
ChemInform Abstract: Reinvestigation of the OP4‐(Li/Na)CoO2‐Layered System and First Evidence of the (Li/Na/Na)CoO2 Phase with OPP9 Oxygen Stacking.
Authors: Berthelot R. , Pollet M. , Carlier D. , Delmas C.
Published: April 2011

The metastable 1:1 Li/Na‐stacked OP4‐Li0.42Na0.37CoO2 phase is synthesized from a mixture of O3‐LiCoO2 and P2‐Na0.7CoO2 in a molar ratio of 42:58 (sealed gold tubes, 920 °C, 24 h, very fast quenching).
ChemInform Abstract: Activation of Oxygen on MgO: O2·‐ Radical Ion Formation on Thin, Metal‐Supported MgO(001) Films.
Authors: Gonchar Anastasia , Risse Thomas , Freund Hans‐Joachim , Giordano Livia , Di Valentin Cristiana , Pacchioni Gianfranco
Published: April 2011

The spontaneous activation of molecular oxygen forming an O2·‐ radical upon adsorption on a 4 monolayer thick MgO(001) film is demonstrated by EPR spectroscopy and DFT calculations.
ChemInform Abstract: Preparation and Superconductivity of New Stage and Polytypic Phases in Potassium‐Intercalated Zirconium Nitride Chloride (KxZrNCl).
Authors: Zheng Zhanfeng , Yamanaka Shoji
Published: April 2011

New polytypic and intermediate‐stage intercalation compounds K0.26ZrNCl, K0.08(thf)yZrNCl, and K0.26(pc)yZrNCl (pc: propylene carbonate) with different amounts of potassium and cointercalation of THF are prepared from a K‐naphthalene solution in THF, and a direct reaction with potassium metal.
ChemInform Abstract: Syntheses and Crystal Structures of the closo‐Borates M2[B7H7] and M[B7H8] (M: PPh4, PNP, and N(n‐Bu4)): The Missing Crystal Structure in the Series [BnHn]2‐ (n: 6—12).
Authors: Schlueter Florian , Bernhardt Eduard
Published: April 2011

The first convenient synthesis of the seven‐vertex closo‐[B7H7]2‐ anion via O2‐oxidation of [B9H9]2‐ is reported.