bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relational thesauri in information retrieval
Authors: Wang Yih‐Chen , Vandendorpe James , Evens Martha 
Published: May 2013

AbstractThis article describes the design and development of a new type of thesaurus based on lexical‐semantic relations. Relational thesauri have been constructed to perform a new type of term classification. These relational thesauri are generally applicable to any document collection and their maintenance is relatively simple. A series of experiments to evaluate thesauri of this new type have been run on an information retrieval system called IRS at Illinois Institute of Technology. The results of experiments with queries enhanced using thesauri based on several different groups of relations have been compared against performance with the original queries. Thesauri from most groups, except antonyms, made improvements in recall as well as in precision. The best results come from a set of ill‐formed queries with few index terms. These results have been analyzed with both precision‐recall graphs and statistical tests. While thesauri that combine a number of relations together have been most effective in a batch environment, there is reason to believe that individual relations will be more useful in an interactive retrieval system that presents index terms to the user and allows him to choose those that best convey his meaning.
Structural equivalence in a journal network
Authors: Doreian Patrick , Fararo Thomas J. 
Published: May 2013

AbstractConcepts and techniques used in contemporary social network analysis are applied to a network of journals based on citation. By means of procedures drawing on the notion of structural equivalence, a set of blocks or positions, containing journals, are delineated. These blocks have a very close correspondence to a categorization of the journals based on their aims and objectives, supporting the idea of treating the journals of a discipline as a status‐role relational system. By means of the reduced image of the network, a highly centralized and hierarchical structure appears. Some hypotheses concerning the structure and operation of journal networks are advanced.
Critical thresholds in co‐citation graphs
Authors: Shaw W. M. 
Published: May 2013

AbstractUsing the Random Graph Hypothesis, the statistical validity of co‐citation graphs has been investigated as a function of co‐citation strength for a given value of citation frequency. The results show that for both high and low values of co‐citation strength the partition of cited documents produced by the co‐citation relationship may be statistically invalid. Critical thresholds can be identified that define the limits of statistical validity. Within these limits, there is a narrow region of statistical validity where the associated structures are not an artifact of the clustering procedure and can be interpreted. It is concluded that the choice of citation and co‐citation thresholds can be influenced by formal considerations which insure statistically meaningful partitions rather than arbitrary decisions which can produce meaningless interpretations. Experimental and theoretical implications for the co‐citation graph and other bibliometric structures are discussed.
Cosmology and the changing role of libraries: An analogy and reflections
Authors: Lucier Richard E. , Dooley James F. 
Published: May 2013

AbstractImmense cultural changes are taking place in contemporary society. We are in the initial stage of a new era in which our society will view itself and its relationship with an increasingly technetronic world in radically different ways. Powered by abundant, proliferating technology, the advent of this new global epoch demands reasoned personal and professional responses reflecting unique modes of thought and behavior. This article discusses these changes and the meaning and depth of their relationship to medical libraries. Ideas for creating organizational environments that allow and encourage people to embrace change and initiate innovations are presented. Only by actively debating and creatively experimenting with these and other ideas will we be able to ensure our continued viability as information specialists and managers in the future.
The changing environment of personal information systems
Authors: Burton Hilary D. 
Published: May 2013

AbstractRecent technological developments are changing the context, and may change the content and form, of personal information systems. Major developments causing such changes are (1) a substantial increase in the commercially available support services, (2) a proliferation of microcomputer systems claiming to support personal systems, (3) the capability to download citations from secondary services into private files, and (4) a developing awareness of, or desire to, incorporate the computer‐based personal system into a broader, integrated information environment which would include other functions such as electronic mail, automated office functions, etc. These developments raise economic questions for the user, will affect efforts to standardize system interfaces, and may bring basic changes in the ways an individual develops and uses his personal information system.
Transferring a national information system from the public sector to the private sector—How the administration on aging did it
Authors: Halpin Peter 
Published: May 2013

AbstractThe Administration on Aging (AoA) sponsored a national information system known as the SCAN system. The SCAN bibliographic database went on‐line in March 1982. Congress, however, had repealed the authority for the clearinghouse, so the Government let all of the services of SCAN expire by September 1982. The Government then tried to keep the SCAN information accessible by offering it to the private sector. The Government solicited applicants through both the Federal Register and the Commerce Business Daily. As a result, the American Association of Retired Persons (AARP) and AoA signed an agreement calling for AARP to make much of the SCAN information accessible on‐line and to update it.
A pilot study using residual newborn dried blood spots to assess the potential role of cytomegalovirus and Toxoplasma gondii in the etiology of congenital hydrocephalus
Authors: Simeone Regina M. , Rasmussen Sonja A. , Mei Joanne V. , Dollard Sheila C. , Frias Jaime L. , Shaw Gary M. , Canfield Mark A. , Meyer Robert E. , Jones Jeffrey L. , Lorey Fred , Honein Margaret A. 
Published: May 2013

AbstractBackgroundCongenital hydrocephalus is a condition characterized by accumulation of cerebrospinal fluid in the ventricles of the brain. Prenatal infections are risk factors for some birth defects. This pilot study investigated whether residual dried blood spots (DBS) could be used to assess infections as risk factors for birth defects by examining the associations between prenatal infection with Toxoplasma gondii (T. gondii) or cytomegalovirus (CMV) with congenital hydrocephalus.MethodsCase‐infants with hydrocephalus (N = 410) were identified among live‐born infants using birth defects surveillance systems in California, North Carolina, and Texas. Control‐infants without birth defects were randomly selected from the same geographic areas and time periods as case‐infants (N = 448). We tested residual DBS from case‐ and control‐infants for T. gondii immunoglobulin M and CMV DNA. When possible, we calculated crude odds ratios (cORs) and confidence intervals (CIs).ResultsEvidence for prenatal T. gondii infection was more common among case‐infants (1.2%) than control‐infants (0%; p = 0.11), and evidence for prenatal CMV infection was higher among case‐infants (1.5%) than control‐infants (0.7%; cOR: 2.3; 95% CI: 0.48, 13.99).ConclusionsPrenatal infections with T. gondii and CMV occurred more often among infants with congenital hydrocephalus than control‐infants, although differences were not statistically significant. This pilot study highlighted some challenges in using DBS to examine associations between certain infections and birth defects, particularly related to reduced sensitivity and specimen storage conditions. Further study with increased numbers of specimens and higher quality specimens should be considered to understand better the contribution of these infections to the occurrence of congenital hydrocephalus. Birth Defects Research (Part A) 97:431–436, 2013. © 2013 Wiley Periodicals, Inc.
Activin‐A in Diabetes‐Induced Cardiac Malformations in Embryos
Authors: Zhao* Zhiyong 
Published: May 2013

BACKGROUNDHeart defects are the most common abnormalities in infants of diabetic mothers. Cardiac malformation is associated with altered expression of the genes in the transforming growth factor β system, including inhibin βA, which forms activin‐A as a homodimer and functions through its effectors, Smad2 and Smad3. This study aimed to investigate the role of activin‐A in diabetes‐induced cardiac malformations.METHODSDiabetes mellitus in female mice (C57BL/6J) was induced via intravenous injection of streptozotocin. The expression of inhibin βA protein and phosphorylation of Smad2 and Smad3 in the embryonic hearts were examined using immunohistochemical, in situ proximity ligation, and immunoblot assays. Embryos and endocardial cushions of nondiabetic mice were cultured in a high concentration of glucose and treated with activin‐A. Mitosis was examined using BrdU incorporation assay and immunohistochemistry of phosphorylated histone H3. Migration of the endocardial cells was assessed using a collagen‐based cell migration assay.RESULTSThe levels of inhibin βA expression and Smad2 and Smad3 activation were significantly reduced by maternal diabetes. Treatment with activin‐A significantly increased cell proliferation in the myocardium and migration of endocardial cells, compared with those in vehicle‐treated high glucose group, to the level in the euglycemic control group.CONCLUSIONSMaternal diabetes suppresses the expression of inhibin βA protein, as well as the activation of Smad2 and Smad3. Activin‐A rescues cell proliferation in the myocardium and migration of the endocardial cells suppressed by hyperglycemia. The activin‐Smad2/3 signaling system appears to play a role in cardiac malformation in diabetic embryopathy. Birth Defects Res (Part B) 98:260–267, 2013. © 2013 Wiley Periodicals, Inc.
Bactericidal properties of the antimicrobial peptide Ib‐AMP4 from Impatiens balsamina produced as a recombinant fusion‐protein in Escherichia coli
Authors: Fan Xiaobo , Schäfer Holger , Reichling Jürgen , Wink Michael 
Published: May 2013

AbstractAntimicrobial peptides (AMPs) represent a novel class of powerful natural antimicrobial agents. As AMPs are bactericidal, production of AMPs in recombinant bacteria is far from trivial. We report the production of Impatiens balsamina antimicrobial peptide 4 (Ib‐AMP4, originally isolated from Impatiens balsamina) in Escherichia coli as a fusion protein and investigate Ib‐AMP4's antimicrobial effects on human pathogens. A plasmid vector pET32a‐Trx‐Ib‐AMP4 was constructed and transferred into E. coli. After induction, a soluble fusion protein was expressed successfully. The Ib‐AMP4 peptide was obtained with a purity of over 90% after nickel affinity chromatography, ultrafiltration, enterokinase cleavage and sephadex size exclusion chromatography. For maximum activity, Ib‐AMP4, which possesses two disulfide bonds, required activation with 5 μg/mL H2O2. Antimicrobial assays showed that Ib‐AMP4 could efficiently target clinical multiresistant isolates including methicillin‐resistant Staphylococcus aureus and extended‐spectrum β‐lactamase‐producing E. coli. Time kill experiments revealed that Ib‐AMP4 is bactericidal within 10 min after application. Haemolysis and cytotoxicity assays implied selectivity towards bacteria, an important prerequisite for clinical applications. Ib‐AMP4 might be an interesting candidate for clinical studies involving patients with septicemia or for coating clinical devices, such as catheters. The method described here may be applicable for expression and purification of other AMPs with multiple disulfide bridges.
Asymmetric Addition of Cyanide to β‐Nitroalkenes Catalysed by Chiral Salen Complexes of Titanium(IV) and Vanadium(V)
Authors: North Michael , Watson James M. 
Published: May 2013

AbstractStructurally well‐defined bimetallic titanium(IV) (salen) and monometallic vanadium(V) (salen) complexes have been used as catalysts for the asymmetric addition of trimethylsilyl cyanide to β‐nitroalkenes to produce chiral nitronitriles with ee values in the range of 79–89 % and conversions up to 100 % at 0 °C. The reaction conditions (solvent, temperature, time and vanadium complex counter‐ion) were optimised, and it was shown that the catalyst loading could be significantly reduced (20 to 2 mol %) and the reaction temperature increased (−40 to 0 °C) compared to previous studies that used an in situ prepared catalyst. The results are compared and contrasted with previous results obtained by using the same catalysts for the asymmetric addition of trimethylsilyl cyanide to aldehydes, and a transition‐state structure for the asymmetric addition of trimethylsilyl cyanide to nitroalkenes is proposed to account for the observed stereochemistry.
Multistep Continuous‐Flow Synthesis in Medicinal Chemistry: Discovery and Preliminary Structure–Activity Relationships of CCR8 Ligands
Authors: Petersen Trine P. , Mirsharghi Sahar , Rummel Pia C. , Thiele Stefanie , Rosenkilde Mette M. , Ritzén Andreas , Ulven Trond 
Published: May 2013

AbstractA three‐step continuous‐flow synthesis system and its application to the assembly of a new series of chemokine receptor ligands directly from commercial building blocks is reported. No scavenger columns or solvent switches are necessary to recover the desired test compounds, which were obtained in overall yields of 49–94 %. The system is modular and flexible, and the individual steps of the sequence can be interchanged with similar outcome, extending the scope of the chemistry. Biological evaluation confirmed activity on the chemokine CCR8 receptor and provided initial structure–activity‐relationship (SAR) information for this new ligand series, with the most potent member displaying full agonist activity with single‐digit nanomolar potency. To the best of our knowledge, this represents the first published example of efficient use of multistep flow synthesis combined with biological testing and SAR studies in medicinal chemistry.
Zeolitic Imidazolate Framework (ZIF)‐Derived, Hollow‐Core, Nitrogen‐Doped Carbon Nanostructures for Oxygen‐Reduction Reactions in PEFCs
Authors: Palaniselvam Thangavelu , Biswal Bishnu P. , Banerjee Rahul , Kurungot Sreekumar 
Published: May 2013

AbstractThe facile synthesis of a porous carbon material that is doped with iron‐coordinated nitrogen active sites (FeNC‐70) is demonstrated by following an inexpensive synthetic pathway with a zeolitic imidazolate framework (ZIF‐70) as a template. To emphasize the possibility of tuning the porosity and surface area of the resulting carbon materials based on the structure of the parent ZIF, two other ZIFs, that is, ZIF‐68 and ZIF‐69, are also synthesized. The resulting active carbon material that is derived from ZIF‐70, that is, FeNC‐70, exhibits the highest BET surface area of 262 m2 g−1 compared to the active carbon materials that are derived from ZIF‐68 and ZIF‐69. The HR‐TEM images of FeNC‐70 show that the carbon particles have a bimodal structure that is composed of a spherical macroscopic pore (about 200 nm) and a mesoporous shell. X‐ray photoelectron spectroscopy (XPS) reveals the presence of Fe‐N‐C moieties, which are the primary active sites for the oxygen‐reduction reaction (ORR). Quantitative estimation by using EDAX analysis reveals a nitrogen content of 14.5 wt. %, along with trace amounts of iron (0.1 wt. %), in the active FeNC‐70 catalyst. This active porous carbon material, which is enriched with Fe‐N‐C moieties, reduces the oxygen molecule with an onset potential at 0.80 V versus NHE through a pathway that involves 3.3–3.8 e− under acidic conditions, which is much closer to the favored 4 e− pathway for the ORR. The onset potential of FeNC‐70 is significantly higher than those of its counterparts (FeNC‐68 and FeNC‐69) and of other reported systems. The FeNC‐based systems also exhibit much‐higher tolerance towards MeOH oxidation and electrochemical stability during an accelerated durability test (ADT). Electrochemical analysis and structural characterizations predict that the active sites for the ORR are most likely to be the in situ generated NFeN2+2/C moieties, which are distributed along the carbon framework.
Aerobic Oxidation of 9H‐Fluorenes to 9‐Fluorenones using Mono‐/Multilayer Graphene‐Supported Alkaline Catalyst
Authors: Zhang Xin , Ji Xuan , Su Ruifei , Weeks Brandon L. , Zhang Zhao , Deng Songlu 
Published: May 2013

AbstractThe synthesis of 9‐fluorenone derivatives has been achieved in high yield and with high purity by aerobic oxidation of 9H‐fluorenes at room temperature in the presence of a graphene‐supported KOH composite that acts as a catalyst in N,N‐dimethylformamide. The new protocol involves very simple work‐up procedures, and the solvent and the catalyst can be recycled and reused. A scaled‐up preparative study employing this method was also conducted and showed its advantages of being both cost‐effective and environmentally friendly, and has potential for application in industrial processes.
Foraging area fidelity for Kemp's ridleys in the Gulf of Mexico
Authors: Shaver Donna J. , Hart Kristen M. , Fujisaki Ikuko , Rubio Cynthia , Sartain Autumn R. , Peña Jaime , Burchfield Patrick M. , Gamez Daniel Gomez , Ortiz Jaime 
Published: May 2013

AbstractFor many marine species, locations of key foraging areas are not well defined. We used satellite telemetry and switching state‐space modeling (SSM) to identify distinct foraging areas used by Kemp's ridley turtles (Lepidochelys kempii) tagged after nesting during 1998–2011 at Padre Island National Seashore, Texas, USA (PAIS; N = 22), and Rancho Nuevo, Tamaulipas, Mexico (RN; N = 9). Overall, turtles traveled a mean distance of 793.1 km (±347.8 SD) to foraging sites, where 24 of 31 turtles showed foraging area fidelity (FAF) over time (N = 22 in USA, N = 2 in Mexico). Multiple turtles foraged along their migratory route, prior to arrival at their “final” foraging sites. We identified new foraging “hotspots” where adult female Kemp's ridley turtles spent 44% of their time during tracking (i.e., 2641/6009 tracking days in foraging mode). Nearshore Gulf of Mexico waters served as foraging habitat for all turtles tracked in this study; final foraging sites were located in water <68 m deep and a mean distance of 33.2 km (±25.3 SD) from the nearest mainland coast. Distance to release site, distance to mainland shore, annual mean sea surface temperature, bathymetry, and net primary production were significant predictors of sites where turtles spent large numbers of days in foraging mode. Spatial similarity of particular foraging sites selected by different turtles over the 13‐year tracking period indicates that these areas represent critical foraging habitat, particularly in waters off Louisiana. Furthermore, the wide distribution of foraging sites indicates that a foraging corridor exists for Kemp's ridleys in the Gulf. Our results highlight the need for further study of environmental and bathymetric components of foraging sites and prey resources contained therein, as well as international cooperation to protect essential at‐sea foraging habitats for this imperiled species.
Phase behavior of symmetrical monounsaturated triacylglycerols
Authors: Smith Kevin W. , Bhaggan Krish , Talbot Geoff 
Published: May 2013

The unique properties of cocoa butter (CB) are due to the fact that it is composed, for the most part, of just three TAGs, 1,3‐dipalmitoyl‐2‐oleoylglycerol (POP), 1,3‐distearoyl‐2‐oleoylglycerol (StOSt), and rac‐1‐palmitoyl‐2‐oleoyl‐3‐stearoylglycerol (POSt). In this study we have examined blends, at 10% intervals, across the ternary of these three TAG by stabilizing them during a lengthy temperature regime designed to induce the most stable polymorph at the point of melting. The liquidus observed is in good agreement with that predicted using the Hildebrand model. A eutectic is seen in each binary system, with a possible ternary eutectic present at about POP:POSt 1:1 and <10% StOSt. CB stabilized following the same regime exhibits solid fat contents much greater than those obtained following the standard IUPAC 2.150(b) stabilization, likely to be due to the presence of the βVI polymorph rather than the βV form.Practical applications: The processing characteristics and final properties of fat based products depend greatly on the composition, crystallization, and melting properties of the fat or fats involved. In the case of chocolate and confectionery, this fat is CB. The present study confirms many of the relevant published phase diagrams and emphasizes the compositional areas having similar melting behavior to that of CB and, hence, suitable for cocoa butter equivalents.
A New Life for an Old Reagent: Fluoroalkyl Amino Reagents as Efficient Tools for the Synthesis of Diversely Fluorinated Pyrazoles
Authors: Pazenok Sergiy , Giornal Florence , Landelle Grégory , Lui Norbert , Vors Jean‐Pierre , Leroux Frédéric R. 
Published: May 2013

AbstractHerein we describe the first practical method for the regioselective preparation of 3,5‐bis(fluoroalkyl)pyrazoles. Starting from commercially available fluoroacetoacetates and by using (tetrafluoroethyl)dimethylamine as a convenient CF2H transfer reagent, this straightforward one‐pot sequence affords highly substituted pyrazoles in good yields and excellent regioselectivity. Furthermore, these carboxylate intermediates were converted into the corresponding pyrazolic acids, which are valuable building blocks for the design of novel bioactive ingredients.
Weighted averaged equations for modeling velocity profiles of 1D steady open channel flows
Authors: Xia Cenling , Benedicenti Luigi , Field Tom 
Published: May 2013

SUMMARYA new mathematical algorithm is proposed to address the essential details of vertical distributions of horizontal velocity for one‐dimensional steady open‐channel flow. This new algorithm comprises a system of weighted averaged equations developed from corresponding Reynolds equations by performing weighted average operations instead of conventional depth average operations. It is the system of weighted averaged equations, instead of the vertical grids, that allows for more hydraulic coefficients identifiable. It can be thought of as an extension of the St. Venant equations to address the vertical distributions of horizontal velocities, as well as the water surface profiles.To avoid the difficult expansion of governing partial differential equations in high order, an indirect scheme is proposed to solve hydraulic variables through their weighted average values. The governing partial differential equations are generated by using a variety of weight functions, and the weighted averages of relevant hydraulic variables are taken as the unknown independent variables to be solved first. Then, on the basis of the values and polynomial expansions of these weighted averaged velocities, a system of linear algebraic equations is generated and the unknown hydraulic variables or their coefficients are easily solved.Note that the new model is not proposed to compete with any three‐dimensional models in modeling accuracy or accommodation ability to all conditions. It just provides a valuable option to study the vertical structure of flow in open channels where only essential detail and reasonable accuracy of vertical distributions are required, and the data availability and other conditions limit the application of fully three‐dimensional models. The performance of the model is evaluated with experimental data of flows in two different flumes. It is shown that the model well predicted the velocity profiles of sections along the centerlines of these flumes with reasonable accuracy and essential details of vertical distributions of horizontal velocity. Copyright © 2013 John Wiley & Sons, Ltd.