bluuebunny/crossref_metadata_2025 huggingface dataset:
Contextualising knowledge–making in Linux user groups
Authors: Lin Yuwei
Published: May 2013

A common critique on free/libre open source software (FLOSS) is that FLOSS–oriented products, often mutated from or based on parallel works, are not really innovative. FLOSS’ development process and subsequent products (e.g. software packages, maintaining services, or the formation of user groups, etc.) definitely denote a kind of innovation driving our world towards a knowledge–based society. This perspective challenges the conventional notion of innovation in technological and economic arenas from a glocalised perspective. I argue that software development is not solely a matter of technical engineering or economic progress. Rather, it also involves cultural, social and political factors.

Through interaction and negotiation, FLOSS innovation is embedded in the translation of problems and knowledge–sharing between user and designer, and between lay and expert. Narratives of Linux users groups (LUGs) show that the influence of local knowledge and tacit skills is very much in evidence in the FLOSS innovation system. Practices in LUGs denote the codification of local knowledge and its translation into more formalised and sophisticated expertise. This raises fundamental questions about whether institutional involvement should continue along its techno–economic route of relying entirely on specialists (programmers) to reach developmental decisions, or whether the process should be made more democratic by allowing a broader range of social interests to have some input into software development.

In this paper, I demonstrate the values of local tinkering, soft skills and tacit knowledge in FLOSS innovation. I investigate how locally defined software problems and locally crafted solutions towards the problems are codified and translated into expert knowledge within FLOSS innovation through intense hands–on practices and ongoing debate. The process of translating local knowledge into formal expertise is analysed in light of data collected from the York Linux User Group (YLUG). While FLOSS is gaining unprecedented recognition at an accelerating pace, and more institutional resources are made available, noticeably from national agencies and industry, it is crucial to get a genuine picture of FLOSS development, on which this paper will shed some light.
A case for Indian insourcing: Open Source interest in IT job expansion
Authors: O’Donnell Casey
Published: May 2013

The controversy surrounding the "off–shoring" of IT jobs from the United States to other countries, in particular to India, has become a focal point in American political discourse and has been widely represented in the media. Disturbingly, little attention has been paid to this occurrence beyond its implications for American employment opportunities. Representing Indian and American IT workers as unified groups whose interests are mutually exclusive and opposed to one another is problematic given the material realities that propel "outsourcing." Among the potential benefits of growing demand for, and supply of, skilled IT workers is increased participation in the Open Source Software (OSS) movement. Expanding global involvement offers a significant opportunity for developing countries to influence the direction, importance, and future of OSS.
Do novel oral anticoagulants do better than standard therapy in the treatment of deep vein thrombosis?
Authors: Brodmann M.
Published: May 2013

The focus of DVT treatment is the prevention of recurrence and thrombus migration by treatment with anticoagulants. The aim is to improve outcomes by reducing clot burden and by preventing thrombus propagation, in order to prevent PE and the development of long-term complication. Actually, initial therapy is parenteral anticoagulation, mainly with low molecular weight heparin followed by a vitamin K antagonist (VKA) for triggered and idiopathic DVT. The long term treatment suggestion with a VKA is for sure the most challenging therapeutic scenario, showing all the disadvantages of VKA especially in the onset phase when therapeutic levels of VKA are difficult to achieve.

The difference between VKAs and NOACs is the fact, that NOACs target a specific factor in the coagulation cascade. At time now two pathways have been chosen for treatment options, the direct inhibition of active sites of thrombin and factor Xa. Routine monitoring is not required and the drugs can be administered in fixed doses, which should increase patient adherence to long term treatment.

At time now, four novel anticoagulants are called to be options for DVT treatment. Rivaroxaban, apixaban and edoxaban are direct FXa inhibitors, whereas dabigtran etexilate is a direct thrombin inhibitor.
Humanoid Introspection: A Practical Approach
Authors: Infantino Ignazio , Pilato Giovanni , Rizzo Riccardo , Vella Filippo
Published: May 2013

Abstract We describe an approach to robot introspection based on self observation and communication. Self observation is what the robot should do in order to build, represent and understand its internal state. It is necessary to translate the state representation in order to build a suitable input to an ontology that supplies the meaning of the internal state. The ontology supports the linguistic level that is used to communicate information about the robot state to the human user.
Online Sensor Information and Redundancy Resolution Based Obstacle Avoidance for High DOF Mobile Manipulator Teleoperation
Authors: Zhang Huatao , Jia Yunyi , Guo Yan , Qian Kui , Song Aiguo , Xi Ning
Published: May 2013

Abstract High degrees of freedom (DOF) mobile manipulators provide more flexibility than conventional manipulators. They also provide manipulation operations with a mobility capacity and have potential in many applications. However, due to high redundancy, planning and control become more complicated and difficult, especially when obstacles occur. Most existing obstacle avoidance methods are based on off-line algorithms and most of them mainly focus on planning a new collision-free path, which is not appropriate for some applications, such as teleoperation and uses many system resources as well. Therefore, this paper presents an online planning and control method for obstacle avoidance in mobile manipulators using online sensor information and redundancy resolution. An obstacle contour reconstruction approach employing a mobile manipulator equipped with an active laser scanner system is also introduced in this paper. This method is implemented using a mobile manipulator with a seven-DOF manipulator and a four-wheel drive mobile base. The experimental results demonstrate the effectiveness of this method.
Performance Evaluations for Super-Resolution Mosaicing on UAS Surveillance Videos
Authors: Camargo Aldo , He Qiang , Palaniappan Kannappan
Published: May 2013

Abstract Unmanned Aircraft Systems (UAS) have been widely applied for reconnaissance and surveillance by exploiting information collected from the digital imaging payload. The super-resolution (SR) mosaicing of low-resolution (LR) UAS surveillance video frames has become a critical requirement for UAS video processing and is important for further effective image understanding. In this paper we develop a novel super-resolution framework, which does not require the construction of sparse matrices. The proposed method implements image operations in the spatial domain and applies an iterated back-projection to construct super-resolution mosaics from the overlapping UAS surveillance video frames. The Steepest Descent method, the Conjugate Gradient method and the Levenberg-Marquardt algorithm are used to numerically solve the nonlinear optimization problem for estimating a super-resolution mosaic. A quantitative performance comparison in terms of computation time and visual quality of the super-resolution mosaics through the three numerical techniques is presented.
Animating Algorithms as a DSP Teaching Tool
Authors: Leis John
Published: May 2013

This paper introduces the notion of ‘animation’ of digital signal processing algorithms and related concepts. The purpose of the paper is threefold: (i) to introduce the idea of animation of algorithms as an adjunct to teaching DSP; (ii) to discuss some possible approaches to developing such animations, and motivate possible scenarios where algorithm animation would be of benefit in explaining abstract DSP principles; and (iii) to provide details on a method which successfully demonstrates the algorithm animations using a web browser without the need for user-installed software or browser plug-ins.
Teaching DSP Implementation: The Big Picture
Authors: Dahnoun N. , Brand J.
Published: May 2013

Starting a digital signal processing (DSP) implementation course can be a daunting task, especially with the advanced DSP algorithms, complex DSP processor architectures and sophisticated development tools that are developed to satisfy consumer demands. These courses can be split into disciplines such as control, audio and video. In this paper the authors are addressing the concerns associated with fast-growing DSP chips and tools and the impact they have on teaching DSP implementation. The authors also provide solutions, advice and suggestions on how to select a DSP, set a DSP implementation course and the associated laboratory hardware and software that fit a specific application.
Development of Brushless D.C. Motor Drive System for Teaching Purposes Using Various PWM Control Techniques
Authors: Tadrist Nadia , Zeroug Houcine , Boukais Boussad
Published: May 2013

In this paper, a test bench was developed for teaching purposes to enhance power electronics and real time control of a brushless d.c. motor. Particular emphasis was placed on PWM techniques and theoretical signal generation using a MATLAB/Simulink environment and experimentally with a DSP programming kit. First, a model was developed in MATLAB/Simulink derived from electrical and mechanical equations for the 120° mode. The control strategies implemented involved two PWM techniques, namely soft and hard switching. The system was built in such a way that students are able to carry out modelling and confirm their results through the test bench using these techniques. The approach used has been effective in generating student satisfaction. Improvements in student learning are evident with regard to the drive control applications, either as a variable speed drive or in embedded systems.
Time-Domain Matrix Analysis of Polyphase FIR Filters
Authors: Balster Eric J. , Fradette Francis D. , Scarpino Frank A. , Hill Kerry L.
Published: May 2013

Polyphase filter design is a common subject studied in discrete systems analysis and digital signal processing (DSP) courses. However, the classic z-domain analysis, utilizing the noble identities, gives a conclusion to the true physical structures of polyphase filters which may not be obvious to many students. The proposed time-domain analysis provides a more straightforward development of polyphase implementation of interpolation and decimation functions, and hopes to provide students with a more visual representation of the polyphase interpolation and decimation processes. Results from a student survey show that over 73% of students believe that the proposed polyphase analysis strengthened their understanding of polyphase filters, and over 71% would prefer to use the proposed method over the traditional z-domain analysis when explaining polyphase filters to others.
Teaching DSP in Digital Control
Authors: Bormann Frank
Published: May 2013

The paper describes an approach to introduce digital signal processors (DSPs) in teaching digital control for undergraduates in electrical engineering. The article focuses first on the increasing demand for computational power from new mathematical approaches to digital control techniques, such as digital power supply, digital motor control, photovoltaic inverters, inverters for solar arrays and LED illuminating. The challenge for educators is to provide both a basic understanding of hardware and software modules on processor technology and a reasonable mathematical background to the underlying theory. Over the last decade the author has developed a set of teaching modules based on the C2000 family of digital signal controllers. As an example of students' work, the paper also describes a project based on an autonomous driving car.
Hands-On DSP Education through Experiments
Authors: Benveniste Rifat , Ünsalan Cem
Published: May 2013

A new graduate from electrical engineering education must know about digital signal processing (DSP) to find a secure place in the competitive jobs market. Although this topic can be taught theoretically, its importance comes from practical applications. Therefore, students must be equipped with appropriate tools. Fortunately, DSP platforms serve this purpose. At Yeditepe University, we established a laboratory to guide students in real-time digital signal processing applications. We selected a Texas Instruments TMS320C6713 DSK platform for this purpose. In this study, we provide several laboratory applications on this platform. We also provide more advanced projects developed by our students which emerged from these applications. We observed that this laboratory improved the understanding of theoretical DSP concepts.
As ciências da vida: de Canguilhem a Foucault
Authors: Portocarrero Vera
Published: May 2013

O conjunto de textos reunidos nesse livro, cronologicamente separados, mas inseridos num único projeto epistemológico, explora o mesmo território: o das ciências da vida. Todos, de maneira bastante homogênea, lidam com a história e com uma tradição que se enraizou no Brasil e, particularmente, com muita força no Rio de Janeiro. O conteúdo desses escritos resulta de anos de pesquisa vivenciada em instituições biomédicas. São agradáveis, bem escritos e maduros: muito próximos da tradição que os inspira.
Reforming research assessment
Authors: Schekman Randy , Patterson Mark
Published: May 2013

It is time for the research community to rethink how the outputs of scientific research are evaluated and, as the San Francisco Declaration on Research Assessment makes clear, this should involve replacing the journal impact factor with a broad range of more meaningful approaches.
A Self‐Standing and Flexible Electrode of Li4Ti5O12 Nanosheets with a N‐Doped Carbon Coating for High Rate Lithium Ion Batteries
Authors: Li Na , Zhou Guangmin , Li Feng , Wen Lei , Cheng Hui‐Ming
Published: May 2013

Flexible energy‐storage devices have attracted growing attention with the fast development of bendable electronic systems. Thus, the search for reliable electrodes with both high mechanical flexibility and excellent electron and lithium‐ion conductivity has become an urgent task. Carbon‐coated nanostructures of Li4Ti5O12 (LTO) have important applications in high‐performance lithium ion batteries (LIBs). However, these materials still need to be mixed with a binder and carbon black and pressed onto metal substrates or, alternatively, by be deposited onto a conductive substrate before they are assembled into batteries, which makes the batteries less flexible and have a low energy density. Herein, a simple and scalable process to fabricate LTO nanosheets with a N‐doped carbon coating is reported. This can be assembled into a film which can be used as a binder‐free and flexible electrode for LIBs that does not require any current collectors. Such a flexible electrode has a long life. More significantly, it exhibits an excellent rate capability due to the thin carbon coating and porous nanosheet structures, which produces a highly conductive pathway for electrons and fast transport channels for lithium ions.
(Super)hydrophobic and Multilayered Amphiphilic Films Prepared by Continuous Assembly of Polymers
Authors: Guntari Stefanie N. , Khin Aaron C. H. , Wong Edgar H. H. , Goh Tor K. , Blencowe Anton , Caruso Frank , Qiao Greg G.
Published: May 2013

The continuous assembly of polymers (CAP) is used to fabricate tailored nanocoatings on a wide variety of substrates. Ring‐opening metathesis polymerization (ROMP) is used to mediate the CAP process (CAPROMP) to assemble specifically designed macromolecules into nanoengineered crosslinked films. Different films composed of single or multiple macromolecules are used to tune the surface wetting characteristics on various planar substrates, including porous substrates such as filter paper and cotton, and non‐porous subtrates such as aluminium foil and glass. By judicious selection of the macromolecules, these substrates, which are hydrophilic in nature, can be rendered (super)hydrophobic. The robustness of the ROMP catalysts and the reinitiation ability of the CAPROMP approach allow the production of layered multicomponent amphiphilic films with on‐demand switchable wettability. Such functional nanocoatings can be potentially applied as self‐cleaning surfaces, as waterproof woven fabrics, and for the next generation of microelectronic devices.
Relay Redox and Lewis Acid Catalysis in the Titanocene‐ Catalyzed Multicomponent Assembly of 1,5‐Enynes
Authors: Lepore Antonio J. , Pinkerton David M. , Ashfeld Brandon L.
Published: May 2013

Herein we describe a direct, multicomponent assembly of 1,5‐enynes. The titanocene‐catalyzed coupling of an aryl aldehyde, iodoalkyne, and allylsilane enables the convergent and rapid synthesis of this versatile architectural motif in good to excellent yields.
Observation of Microstructural Evolution in Li Battery Cathode Oxide Particles by In Situ Electron Microscopy
Authors: Miller Dean J. , Proff Christian , Wen J. G. , Abraham Daniel P. , Bareño Javier
Published: May 2013

We developed a simple approach to carry out in situ electron microscopy of single Li‐ion battery cathode particles during electrochemical cycling. We focused on Li(Ni0.8Co0.15Al0.05)O2‐based cathode materials because life‐cycle tests suggest a strong contribution of the cathode material to changes in cell impedance. In situ scanning electron microscopy was carried out operando during cycling and at various stages by interrupted cycling. Our work revealed several important aspects of cathode oxide particle dynamics: significant separations develop between grains even during the very first charge (oxide delithiation) and electrolyte penetration through that crack network all the way into the particle interior. Comparing these results to post‐test microstructural characterization of oxide particles subjected to extensive cycling confirms the occurrence of these processes in practical cells and suggests that the physical separation and isolation of grains may contribute to performance degradation of lithium‐ion cells.
Energy generation using thermopower waves: Experimental and analytical progress
Authors: Mahajan Sayalee G. , Wang Qing Hua , Strano Michael S. , Abrahamson Joel T.
Published: May 2013

Thermopower waves convert chemical energy into electrical power using nanostructured thermal conduits like carbon nanotubes (CNTs) by taking advantage of their high thermal conductivity to propagate the heat released by an exothermic reaction of a fuel layer coated around the conduit. Electron–phonon coupling in the CNTs then leads to an electrical output. Previous work using cyclotrimethylene‐trinitramine coated around multiwalled CNTs has shown electrical output as high as 7 kW kg−1. This phenomenon has potential to aid the manufacture of nanoscale power sources capable of releasing large power pulses for specific applications. Researchers have studied the effects of other system properties, including the conduit thermal conductivity, the chemical properties of the fuel, and the coupling of the reactions to inorganic thermoelectric materials. An analytical solution for the governing heat and mass balance equations has also been derived. Here, we review the progress made in the field of thermopower waves. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3333–3341, 2013
Familial trisomy 6p in mother and daughter
Authors: Savarese Marco , Grandone Anna , Perone Lucia , Blanco Francesca Del Vecchio , De Luca Giuseppina , Di Fruscio Giuseppina , Fogu Giuseppina , Piluso Giulio , Perrone Laura , del Giudice Emanuele Miraglia , Nigro Vincenzo
Published: May 2013

Several patients with partial trisomy 6p resulting from parental balanced translocations or from a de novo duplication or insertion have already been described. Here, we report on the first case of familial pure trisomy 6p as a result of interstitial tandem duplication. The patient, an 11‐year‐old female, presented with mild dysmorphic features, moderate intellectual disability with behavioral disturbances, immunodeficiency, and epilepsy. Conventional cytogenetic analysis showed a duplication of the 6p region in the patient and in her mother presenting with a partially overlapping phenotype. The rearrangement was confirmed and defined by molecular cytogenetic analysis, including FISH and array CGH analysis showing a gain of ∼13.8 Mb from 6p12.3 to 6p21.31. The phenotype of a pure partial trisomy 6p is extremely heterogeneous depending on the gene contents of the duplicated region. The clinical features of our patients have been compared with overlapping cases from the literature. © 2013 Wiley Periodicals, Inc.
Brief communication: A midtarsal (midfoot) break in the human foot
Authors: DeSilva Jeremy M. , Gill Simone V.
Published: May 2013

The absence of a midtarsal break has long been regarded as a derived feature of the human foot. Humans possess a rigid midfoot that acts as an efficient lever during the propulsive phase of bipedal gait. Non‐human primates, in contrast, have a more mobile midfoot that is adaptive for tree climbing. Here, we report plantar pressure and video evidence that a small percentage of modern humans (n = 32/398) possess both elevated lateral midfoot pressures and even exhibit midfoot dorsiflexion characteristic of a midtarsal break. Those humans with a midtarsal break had on average a significantly flatter foot than those without. Midtarsal breakers also had significantly more medial weight transfer (pronation) during the stance phase of gait than those without this midfoot mobility. These data are in accordance with Elftman (Clin Orthop 16 (1960) 41–45) who suggested that pronation aligns the axes of the transverse tarsal joint, permitting elevated midfoot mobility. Am J Phys Anthropol 151:495–499, 2013.© 2013 Wiley Periodicals, Inc.
Influence of the dispersion of nano titanium dioxide on the tribological performance of fabric self‐lubricating liner
Authors: Qi Xiaowen , Jia Zhining , Yang Yulin
Published: May 2013

Nanoparticles with unique properties have been widely used in various fields. The tribological performance of the fabric self‐lubricating liner, which is used as the main component of spherical plain bearings, directly affects the bearing service life. The purpose of this study was to prepare a self‐lubricating liner enhanced with nano titanium dioxide (nano‐TiO2) by dispersion technology. The effects of several factors on the dispersion of nano‐TiO2 were studied in detail. The effects of the dispersion of nano‐TiO2 on the tribological properties of a self‐lubricating liner were analyzed comparatively. The best dispersing conditions were determined through experiments and statistical characterization. From the results of the tribological tests, the fabric self‐lubricating liner reinforced with nano‐TiO2 showed better antifriction and wear‐resistant properties than that without nanoparticles. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2100–2105, 2013
Synthesis of azobenzene‐containing side chain liquid crystalline diblock copolymers using RAFT polymerization and photo‐responsive behavior
Authors: Sun Wuqiong , He Xiaohua , Liao Xiaojuan , Lin Shaoliang , Huang Wei , Xie Meiran
Published: May 2013

Well‐defined azobenzene‐containing side chain liquid crystalline diblock copolymers composed of poly[6‐[4‐(4‐methoxyphenylazo)phenoxy]hexyl methacrylate] (PAzoMA) and poly(glycidyl methacrylate) (PGMA) were synthesized by a two‐step reversible addition–fragmentation chain transfer polymerization (RAFT). The thermal liquid‐crystalline phase behavior of the PGMA‐b‐PAzoMA diblock copolymers in bulk were measured by differential scanning calorimetry (DSC) and polarized light microscopy (POM). The synthesized diblock copolymers exhibited a smectic and nematic liquid crystalline phase over a relatively wide temperature range. With increasing the weight fraction of the PAzoMA block, the phase transition temperatures, and corresponding enthalpy changes increased. Atomic force microscope (AFM) measurements confirmed the formation of the microphase separation in PGMA‐b‐PAzoMA diblock copolymer thin films and the microphase separation became more obvious after cross‐linking the PGMA block. The photochemical transition behavior of the PGMA‐b‐PAzoMA diblock copolymers in solution and in thin films were investigated by UV–vis spectrometry. It was found that the trans–cis isomerization of diblock copolymers was slower than that of the corresponding PAzoMA homopolymer and the photoisomerization rates decreased with increasing either the length of PAzoMA block or PGMA block. The photo‐induced isomerization in solid films was quite different with that in CHCl3 solution due to the aggregation of the azobenzene chromophore. The cross‐linking structures severely suppressed the photoisomerization of azobenzene chromophore. These results may provide guidelines for the design of effective photo‐responsive anisotropic materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2165–2175, 2013
Preparation of polypropylene single‐polymer composites by injection molding
Authors: Wang Jian , Mao Qianchao , Chen Jinnan
Published: May 2013

The hot compaction process is still the principle method to produce single‐polymer composites (SPCs) at present, which limits the industrial mass production of SPCs. In this article, an approach of preparing SPCs by injection molding was demonstrated. Polypropylene (PP) SPCs were prepared at different temperature and pressure. The flexural properties of the PP SPCs were tested. The optimum processing parameters, injection pressure of 140 MPa and nozzle temperature of 220°C were obtained. Flexural strength of the PP SPCs reached up to 43.3 MPa, which is 54.2% higher than that of nonreinforced PP. Flexural strength can be promoted by raising the injection pressure and nozzle temperature. The morphology of the fibers in the PP SPCs was investigated by optical microscope and scanning electron microscopy techniques. The matrix melt was able to penetrate into fiber webs under appropriate temperature and pressure, good interfacial compatibility and bonding properties were obtained. As the injection and holding pressure increased, the penetration capacity could be improved and the arrangement of fibers tended to be closer. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2176–2183, 2013
The influence of injection molding parameters on electrical properties of PC/ABS‐MWCNT nanocomposites
Authors: Wegrzyn Marcin , Juan Sara , Benedito Adolfo , Giménez Enrique
Published: May 2013

The influence of injection molding parameters on electrical properties and morphology of PC/ABS‐MWCNT nanocomposites is presented in this article. Investigation is based on the masterbatch of 5.0 wt % carbon nanotubes obtained by melt‐mixing. Further processing includes dilution of this nanocomposite to desired concentrations on twin‐screw extruder and injection molding or direct dilution of masterbatch in injection molding. Additionally, reprocessing of materials formed by compression and injection molding is presented along with the change in electrical conductivity. Morphology differs strongly between the two processing paths showing change in agglomeration behavior between nanotubes concentrations. Electrical properties show dependence on injection velocity and melt temperature in both applied processing paths. Moreover, electrical conductivity recovery is proved after injection and compression molding. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2152–2158, 2013
Degradation of graft polymer and blend based on cellulose and poly(L‐lactide)
Authors: Dai Lin , Li Dan , He Jing
Published: May 2013

Degradable polymers were prepared by blending and graft polymerization of cellulose and poly(L‐lactide) (PLLA). The cellulose/poly(L‐lactide) blends and cellulose‐graft‐poly(L‐lactide) polymers were characterized by FTIR, NMR, DSC, and TGA. Wide‐angle X‐ray powder diffraction (WAXD) and degradation tests [by alkaline, phosphate‐buffered saline solution (PBS), and enzyme solution] showed changes in the crystalline structure as a result of degradation. The results indicated that blending and graft polymerization could affect crystallization of the polymers and promote the degradability. The polymers with low degree of crystallinity showed higher degradability. In contrast, enzyme, alkaline, and PBS degradated material decreased rate of polymers degradation. In addition, high levels of PLLA resulted in a decrease in degradation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2257–2264, 2013
Synthesis and Biological Evaluation of Pyrazoline Derivatives Bearing an Indole Moiety as New Antimicrobial Agents
Authors: Özdemir Ahmet , Altintop Mehlika Dilek , Kaplancıklı Zafer Asim , Turan‐Zitouni Gülhan , Karaca Hülya , Tunalı Yağmur
Published: May 2013

1‐(p‐Methylphenyl)‐3,5‐diaryl‐2‐pyrazoline derivatives (2a–f) were synthesized via the treatment of 1‐(1H‐indol‐3‐yl)‐3‐aryl‐2‐propen‐1‐ones (1a–f) with p‐methylphenylhydrazine hydrochloride in hot acetic acid. The structures of these compounds were elucidated by IR, 1H NMR, and mass spectral data and elemental analysis. These compounds were investigated for their antimicrobial activity. Brine‐Shrimp lethality assay was carried out to determine the toxicity of the compounds. Compound 2e, which is the pyrazoline derivative bearing the 2,5‐dichlorophenyl moiety, can be identified as the most promising agent against Klebsiella pneumoniae (ATCC 13883) and Candida glabrata (ATCC 36583) due to its inhibitory effects on K. pneumoniae and C. glabrata with a MIC value of 100 µg/mL as a non‐toxic agent (LC50 > 1000 µg/mL).
Performance of Anti–Cyclic Citrullinated Peptide Assays Differs in Subjects at Increased Risk of Rheumatoid Arthritis and Subjects With Established Disease
Authors: Demoruelle M. Kristen , Parish Mark C. , Derber Lezlie A. , Kolfenbach Jason R. , Hughes‐Austin Jan M. , Weisman Michael H. , Gilliland William , Edison Jess D. , Buckner Jane H. , Mikuls Ted R. , O'Dell James R. , Keating Richard M. , Gregersen Peter K. , Norris Jill M. , Holers V. Michael , Deane Kevin D.
Published: May 2013

Objective

To compare the diagnostic accuracy and agreement of commonly available assays for anti–citrullinated protein antibodies in patients with established rheumatoid arthritis (RA) and subjects at increased risk of RA.

Methods

Tests for anti–cyclic citrullinated peptide (anti‐CCP) antibodies were performed using CCP2 IgG and CCP3.1 IgA/IgG enzyme‐linked immunosorbent assays in the following groups: probands with established RA (n = 340) from the Studies of the Etiology of Rheumatoid Arthritis (SERA) cohort and their first‐degree relatives (FDRs) without inflammatory arthritis (n = 681), Department of Defense Serum Repository (DoDSR) RA cases with pre–RA diagnosis samples (n = 83; 47 cases also had post–RA diagnosis samples), and blood donor and DoDSR control subjects (n = 283).

Results

In patients with established RA, the CCP2 assay was more specific (99.2% versus 93.1%; P < 0.01) but less sensitive (58.7% versus 67.4%; P = 0.01) than the CCP3.1 assay; the specificity of the CCP3.1 assay increased to 97.2% when cutoff levels ≥3‐fold the standard level were considered. In all subjects, CCP3.1 assay positivity (using standard cutoff levels) was more prevalent. Among DoDSR cases, the CCP2 assay was more specific than the CCP3.1 for predicting a future diagnosis of RA, and higher CCP levels trended toward increasing specificity for the development of RA within 2 years. At standard cutoff levels, assay agreement was good in patients with established RA (κ = 0.76) but poor in FDRs without inflammatory arthritis (κ = 0.25).

Conclusion

Anti‐CCP assays differ to an extent that may be meaningful for diagnosing RA in patients with inflammatory arthritis and evaluating the natural history of RA development in subjects at risk of RA. The mechanisms underlying these differences in test performance need further investigation.
Low‐Background, Highly Sensitive DNA Biosensor by Using an Electrically Neutral Cobalt(II) Complex as the Redox Hybridization Indicator
Authors: Wang Qingxiang , Ding Yingtao , Wang Liheng , Ni Jiancong , Yu Zhanglong , Lin Haibin , Gao Feng
Published: May 2013

An electrically neutral cobalt complex, [Co(GA)2(phen)] (GA=glycollic acid, phen=1,10‐phenathroline), was synthesized and its interactions with double‐stranded DNA (dsDNA) were studied by using electrochemical methods on a glassy carbon electrode (GCE). We found that [Co(GA)2(phen)] could intercalate into the DNA duplex through the planar phen ligand with a high binding constant of 6.2(±0.2)×105 M−1. Surface studies showed that the cobalt complex could electrochemically accumulate within the modified dsDNA layer, rather than within the single‐stranded DNA (ssDNA) layer. Based on this feature, the complex was applied as a redox‐active hybridization indicator to detect 18‐base oligonucleotides from the CaMV35S promoter gene. This biosensor presented a very low background signal during hybridization detection and could realize the detection over a wide kinetic range from 1.0×10−14 M to 1.0×10−8 M, with a low detection limit of 2.0 fM towards the target sequences. The hybridization selectivity experiments further revealed that the complementary sequence, the one‐base‐mismatched sequence, and the non‐complementary sequence could be well‐distinguished by the cobalt‐complex‐based biosensor.
A novel phosphorescence sensor for Co2+ ion based on Mn‐doped ZnS quantum dots
Authors: Bian Wei , Ma Jing , Liu Qiaoling , Wei Yanli , Li Yingfu , Dong Chuan , Shuang Shaomin
Published: May 2013

N‐acetyl‐l‐cysteine‐capped Mn‐doped ZnS quantum dots (QDs) were prepared by hydrothermal methods. It could emit phosphorescence at 583 nm with the excitation wavelength at 315 nm. The phosphorescence intensity of QDs could be quenched dramatically by increasing the concentration of Co2+ ion. The novel phosphorescence sensor based on N‐acetyl‐l‐cysteine‐capped QDs was developed for detecting Co2+ ion with a linear dynamic range of 1.25 × 10–6–3.25 × 10–5 m. The limit of detection and RSD were 6.0 × 10–8 m and 2.3%, respectively. Interference experiments showed excellent selectivity over numerous cations such as alkali, alkaline earth and transitional metal ions. The possible quenching mechanism was also examined by phosphorescence decays. The proposed phosphorescence method was further applied to the trace determination of Co2+ ion in tap and pond water samples with recoveries of 97.75–103.32%. Copyright © 2013 John Wiley & Sons, Ltd.
Procedural modeling of trees based on convolution sums of divisor functions for real‐time virtual ecosystems
Authors: Kim Jinmo , Kim Daeyeoul , Cho Hyungje
Published: May 2013

This study proposes a novel procedural modeling method using convolution sums of divisor functions to model a variety of natural trees in a virtual ecosystem efficiently. The basic structure of the modeling method defines the growth grammar, including the branch propagation, a growth pattern of branches and leaves, and a process of growth deformation for various tree generation. Here, the proposed procedural method for trees is to utilize convolution sums of divisor functions as a novel approach. The structure of convolution sums has branch propagation of a uniform pattern, which is controllable, so that it is efficient for real‐time virtual ecosystem construction. Furthermore, it can process changes of environment factors or growth deformation for various and unique tree generation simply through the properties of divisor functions. Finally, an experiment is performed in order to evaluate our proposed modeling method whether it can generate natural and various tree models, and a real‐time virtual ecosystem of a large area where a variety of trees are presented using the modeling method can be constructed efficiently.Copyright © 2013 John Wiley & Sons, Ltd.
Attempts toward the Synthesis of the Peptaibol Antiamoebin by Using the ‘Azirine/Oxazolone Method’
Authors: Blaser Pia , Altherr Werner , Linden Anthony , Heimgartner Heinz
Published: May 2013

The two segments, 1–9 and 10–16, of the peptaibol antibiotic antiamoebin I, i.e., the nonapeptide Ac‐Phe‐Aib‐Aib‐Aib‐D,L‐Iva‐Gly‐Leu‐Aib‐Aib‐OH (15) and the heptapeptide Z‐Hyp‐Gln‐D,L‐Iva‐Hyp‐Aib‐Pro‐Pheol (34), have been prepared as mixtures of the epimers containing D,L‐Iva. All α,α‐disubstituted α‐amino acids were introduced by the ‘azirine/oxazolone method’, in which amino or peptide acids are coupled with the corresponding 2H‐azirin‐3‐amines, followed by selective hydrolysis of the terminal amide bond. The amino acids Hyp and Gln were introduced as Z‐protected4) (2S,4R)‐4‐(tert‐butoxy)proline (19) and methyl N‐[bis(4‐methoxyphenyl)methyl]glutamine (26). Coupling of peptide segments was achieved via the ‘mixed anhydride’ method, the DCC/HOBt or TBTU/HOBt strategy. The crystal structure of the segment 6–9 was determined by X‐ray crystallography and displayed the presence of a β‐turn conformation.
Spectroscopically Labeled Peptaibiotics. Synthesis and Properties of Selected Trichogin GA IV Analogs Bearing a Side‐Chain‐Monofluorinated Aromatic Amino Acid for19F‐NMR Analysis
Authors: Peggion Cristina , Biondi Barbara , Battistella Claudia , De Zotti Marta , Oancea Simona , Formaggio Fernando , Toniolo Claudio
Published: May 2013

We prepared by solid‐phase methods, chromatographically purified, and characterized three analogs of the ten‐amino acid‐residue, membrane‐active, lipopeptaibiotic trichogin GA IV, each containing a single (4‐fluorophenyl)alanine in position 3, 7, or 10, where it replaces the hydrophobic residue Leu3, Leu7, or Ile10, respectively. We incorporated the fluorine probe based on the observation that the19F‐NMR technique has been extensively utilized to analyze peptidemembrane interactions in biological systems. A detailed conformational investigation in solution, including a membrane‐mimetic environment, was performed on these compounds using FT‐IR absorption, CD, and 2D‐NMR, combined with molecular‐dynamics calculations. The experimentally observed, mixed310/α‐helical structures unequivocally show that the principal conformational features of trichogin GA IV are preserved in all three analogs. Analogies and differences between the behavior of the natural lipopeptaibiotic and those of the peptides characterized by the side‐chain monofluorinated aromatic amino acid were found in membrane‐permeabilization experiments and antimicrobial assays. The results of a preliminary solution19F‐NMR study support the view that the19F label is an excellent reporter for changes in the helical environment of the peptide.
Electrocatalytic Reduction of Nitrate on a Pt Electrode Modified by p‐Block Metal Adatoms in Acid Solution
Authors: Yang Jian , Calle‐Vallejo Federico , Duca Matteo , Koper Marc T. M.
Published: May 2013

Nitrate reduction was investigated on a polycrystalline Pt electrode modified with p‐block metals, such as indium, gallium, thallium, tin, lead, arsenic, antimony, bismuth, zinc, and cadmium, in both perchloric and sulfuric acid solution. Online electrochemical mass spectrometry was applied to detect volatile products on the electrode surface. In perchloric acid, tin, cadmium, indium, and gallium were found as active promoters for nitrate reduction, and N2O was detected as the main product for cadmium‐ and indium‐modified Pt electrode, whereas the tin‐modified electrode produced both NO and N2O. Lead cations inhibited nitrate reduction, but N2O was still formed selectively. In sulfuric acid, tin was an active promoter and showed the same coverage dependence for the product distribution as was reported previously for perchloric acid. Thallium performed similarly to germanium in that both metal cations only promoted nitrate reduction in sulfuric acid but not in perchloric acid, which could be attributed to their effect on disordering the bisulfate adsorption on Pt to recover active sites for nitrate reduction. Arsenic, antimony, and bismuth exhibited a similar effect on nitrate reduction on Pt sites in both acid electrolytes; they inhibited nitrate reduction on free Pt sites in the low‐potential range. Among the p‐block metals that were investigated, tin was the most active promoter for nitrate reduction, considering both the anion effect and the product distribution. DFT calculations were performed to gain insight into the promoting role of the two most active promoters, tin and indium.
Ag/AgBr‐Grafted Graphite‐like Carbon Nitride with Enhanced Plasmonic Photocatalytic Activity under Visible Light
Authors: Xu Yang‐Sen , Zhang Wei‐De
Published: May 2013

Ag/AgBr‐grafted graphite‐like carbon nitride (g‐C3N4) is fabricated by the in situ photoreduction of AgBr/g‐C3N4 hybrids prepared by a deposition–precipitation method. The Ag/AgBr/g‐C3N4 hybrids exhibit a strong absorbance in the visible and near‐IR region because of the surface plasmon resonance absorption of Ag nanocrystals. Compared with bare g‐C3N4 and Ag/AgBr nanoparticles, a 28‐fold and six‐fold enhancement in the degradation rate of rhodamine B is observed over Ag/AgBr/g‐C3N4 hybrids under visible‐light irradiation, respectively. The immense enhancement of the photocatalytic activity is attributed to the extended absorption in the visible‐light region, effective charge separation, and synergistic enhancement in the ternary Ag/AgBr/g‐C3N4 system. Moreover, the composite can be reclaimed easily by sedimentation without any decrease of its photocatalytic activity. This study provides new insight into the fabrication of highly efficient and stable g‐C3N4‐based plasmonic photocatalysts and facilitates their practical application to solve environmental issues.
Shape‐Persistent (Pt‐salphen)2 Phosphorescent Coordination Frameworks: Structural Insights and Selective Perturbations
Authors: Guo Zhengqing , Yiu Shek‐Man , Chan Michael C. W.
Published: May 2013

The development of molecular frameworks derived from binuclear platinum(II) aromatic Schiff base (salphen) complexes and their supramolecular chemistry have been undertaken. A series of axially rotating (Pt‐salphen)2 luminophores, tethered in a cofacial manner by a rigid linker (xanthene, 1; dibenzofuran, 2; biphenylene, 3), was synthesized in which the O(salphen) groups are potentially amenable for guest‐binding. The molecular structures of 1 and 3 have been determined by X‐ray crystallography, revealing intra‐ and intermolecular π‐stacking interactions, as well as contrasting syn (1) and anti (3) configurations, for the (Pt‐salphen)2 moiety. All complexes are luminescent in solution at room temperature. Their photophysical and solvatochromic properties have been examined, and the emissions are assigned to mixed triplet O(p)/Pt(d)→π*(diimine) excited states. The red‐shifted fluid emissions and lower quantum yields of 1 and 3, relative to 2, are ascribed to enhanced intramolecular π‐stacking interactions. Photophysical changes and selective responses to metal ions (particularly Pb2+) have been investigated by using various spectroscopic methods and DFT calculations, and through comparative studies with control complexes. A plausible binding mechanism is proposed based on occupation of the O(salphen)‐binding cavity, which induces perturbation of intramolecular π–π interactions, and hence the self‐quenching and emission properties, of the (Pt‐salphen)2 unit.
ChemInform Abstract: Effect of Cation Ordering on the Electronic and Lattice Dynamic Properties of Ag2CdGeS4 Polytypes: First‐Principle Calculation.
Authors: Wei Lei , Fan Weiliu , Li Yanlu , Zhao Xian , Yang Lei
Published: May 2013

Theoretical results obtained for three Ag2CdGeS4 polytypes (two of space group Pna21, one of Pmn21) show the effects of cation arrangement on the electronic and lattice dynamic properties such as bonding strength, band structure, and IR spectrum.
ChemInform Abstract: Photochemical Reductive Elimination of [PtIV(NH3)4(NH2)Cl] 2+: Photogeneration of Hydrazine.
Authors: Kunkely Horst , Vogler Arnd
Published: May 2013

Hydrazine and [PtII(NH3)3Cl]+ are generated by photochemical reductive elimination of [PtIV(NH3)4(NH2)Cl]2+ (white light irradiation, λ < 250 nm).
ChemInform Abstract: Molten Salt Flux Synthesis and Crystal Structure of a New Open‐Framework Uranyl Phosphate Cs3(UO2)2(PO4)O2: Spectroscopic Characterization and Cationic Mobility Studies.
Authors: Yagoubi S. , Renard C. , Abraham F. , Obbade S.
Published: May 2013

Yellow single crystals of Cs3(UO2)2(PO4)O2 are prepared by flux melting of the precursor (UO2)3(PO4)2 (H2O)4 using excess CsI as fluxing agent (Pt crucible, 750 °C, 10 h; 7 °C/h cooling rate).
ChemInform Abstract: B‐Site Deficiencies in A‐Site‐Ordered Perovskite LaCu3Pt3.75O12.
Authors: Yamada Ikuya , et al. et al.
Published: May 2013

The new A‐site ordered title perovskite (space group Im$\bar 3$) is synthesized by replacing Ca2+ with La3+ in the recently reported perovskite CaCu3Pt4O12 under high‐pressure and high‐temperature conditions of 15 GPa and 1100 °C.
ChemInform Abstract: Preparation of Recoverable Pd Catalysts for Carbonylative Cross‐Coupling and Hydrogenation Reactions.
Authors: Niu Jian‐Rui , Huo Xing , Zhang Feng‐Wei , Wang Hai‐Bo , Zhao Ping , Hu Wu‐Quan , Ma Jiantai , Li Rong
Published: May 2013

The catalyst can be easily recycled using a magnet and reused for further transformations.
ChemInform Abstract: Pd(II)‐Catalyzed Highly Regio‐ and Stereoselective Assembly of C—C Double Bonds: An Efficient Method for the Synthesis of 2,4‐Dihalo‐1,3,5‐trienes from Alkynols.
Authors: Jiang Huanfeng , Gao Yang , Wu Wanqing , Huang Yubing
Published: May 2013

The conversion of tert‐propargylic alcohols (I) into trienes (II) and (IV) proceeds with high stereoselectivity, whilst mixtures of isomers (VI) and (VII)/(VIII) are obtained from alcohols (V).
ChemInform Abstract: Nitroalkenes as Carbonyl Surrogates in Arylmethyl‐homoallylic Alcohol Forming One‐Pot Allylation Reactions in Water.
Authors: Lin Mei‐Huey , Lin Wei‐Cheng , Liu Han‐Jun , Chuang Tsung‐Hsun
Published: May 2013

The reaction is proposed to proceed via initial generation of a nitrostyrene radical anion by SET from tin followed by bisprotonation leading to a nitronic acid.
ChemInform Abstract: Samarium Diiodide Promoted Reduction of 3,6‐Dihydro‐2H‐1,2‐oxazines: Competition of 1,4‐Amino Alcohol Formation and Ring Contraction to Pyrrole Derivatives.
Authors: Jasinski Marcin , Watanabe Toshiko , Reissig Hans‐Ulrich
Published: May 2013

The title reaction provides enantiopure 1,4‐amino alcohols [(II), (V)‐(IX)].
ChemInform Abstract: Chemoselective Amide Formation Using O‐(4‐Nitrophenyl)hydroxylamines and Pyruvic Acid Derivatives.
Authors: Kumar Sonali , Sharma Rashi , Garcia Megan , Kamel Joseph , McCarthy Caroline , Muth Aaron , Phanstiel Otto IV
Published: May 2013

The reaction allows an efficient access to amides.
ChemInform Abstract: Fluorinated 5‐ and 7‐Membered Carbacycle Motifs by Reaction of Difluorocarbene with Acetylene Ethers.
Authors: Chia Poh Wai , Bello Davide , Slawin Alexandra M. Z. , O'Hagan David
Published: May 2013

The reaction of acetylene ethers (I) with trimethyl(trifluoromethyl)silane leads to a mixture of cyclohepta‐1,4‐dienes (III) and bicyclo[2.1.1]hex‐2‐enes (IV).
ChemInform Abstract: Sterically Controlled Alkylation of Arenes Through Iridium‐Catalyzed C—H Borylation.
Authors: Robbins Daniel W. , Hartwig John F.
Published: May 2013

This publication describes the site‐selective alkylation, allylation, and benzylation of arenes via in‐situ‐generated aryl pinacol boronates.
ChemInform Abstract: A New Recoverable Au(III) Catalyst Supported on Magnetic Polymer Nanocomposite for Aromatic Bromination.
Authors: Li Bai , Gao Linfeng , Bian Fengling , Yu Wei
Published: May 2013

The catalyst (I) can be used for the halogenation process with an activity that is comparable to homogeneous AuCl3.