bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic and simultaneous MR measurement of R1 and R2* changes during respiratory challenges for the assessment of blood and tissue oxygenation
Authors: Remmele Stefanie , Sprinkart Alois M. , Müller Andreas , Träber Frank , von Lehe Marec , Gieseke Jürgen , Flacke Sebastian , Willinek Winfried A. , Schild Hans H. , Sénégas Julien , Keupp Jochen , Mürtz Petra 
Published: August 2012

AbstractThis work presents a novel method for the rapid and simultaneous measurement of R1 and R2* relaxation rates. It is based on a dynamic short repetition time steady‐state spoiled multigradient‐echo sequence and baseline R1 and B1 measurements. The accuracy of the approach was evaluated in simulations and a phantom experiment. The sensitivity and specificity of the method were demonstrated in one volunteer and in four patients with intracranial tumors during carbogen inhalation. We utilized (ΔR2*, ΔR1) scatter plots to analyze the multiparametric response amplitude of each voxel within an area of interest. In normal tissue R2* decreased and R1 increased moderately in response to the elevated blood and tissue oxygenation. A strong negative ΔR2* and ΔR1 response was observed in veins and some tumor areas. Moderate positive ΔR2* and ΔR1 response amplitudes were found in fluid‐rich tissue as in cerebrospinal fluid, peritumoral edema, and necrotic areas. The multiparametric approach was shown to increase the specificity and sensitivity of oxygen‐enhanced MRI compared to measuring ΔR2* or ΔR1 alone. It is thus expected to provide an optimal tool for the identification of tissue areas with low oxygenation, e.g., in tumors with compromised oxygen supply. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.
Synthesis of crosslinked poly(butyl methacrylate‐co‐pentaerythritol triacrylate) gel by single electron transfer‐living radical polymerization and its oil‐absorbing properties
Authors: Fan Lijun , Chen Hou , Hao Zhihai , Tan Zhi 
Published: August 2012

AbstractA novel high oil‐absorbing crosslinked gel was synthesized by copolymerization of butyl methacrylate (BMA) with a small amount of pentaerythritol triacrylate (PETA) crosslinker using single electron transfer‐living radical polymerization (SET–LRP) initiated with carbon tetrachloride (CCl4) and catalyzed by Cu(0)/hexamethylenetetramine (HMTA) in N, N‐dimethylformamide (DMF). The polymerization followed first‐order kinetics as indicated by linear increase of monomer concentration with reaction time. Effects of reaction temperature, crosslinker, initiator, and catalyst on the oil‐absorbing properties of the crosslinked gel were investigated in detail. The oil absorptions of the crosslinked gel to chloroform, toluene could reach 51.9, 34.5 g/g, respectively. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Anti‐AIDS active polyrotaxane‐AZT conjugates with bioactive bulky stoppers and their nanoparticles
Authors: Jung Sungmo , Swamy B. Yerri , Moon Jin‐Bok , Kim Dong‐Hyun , Chung Ildoo 
Published: August 2012

AbstractNew anti‐HIV active agents, polyrotaxane‐AZT conjugates with various bioactive bulky stoppers such as 3′‐azido‐3′‐deoxythymidine (AZT) and tocopherol and their nanoparticles were synthesized and characterized. The degree of AZT substitution of the conjugates was calculated from ELEM. ANAL and ranged from 1.8 to 5.9, respectively. The in vitro antiviral activity of these conjugates was determined and used to evaluate their potential applications in anti‐AIDS drugs. The in vitro anti‐HIV activities indicate that the synthesized polyrotaxane‐AZT conjugates and their nanoparticles against HIV‐1 and HIV‐2 strains were more potent inhibitors than free AZT, with reduced cytotoxicities against uninfected MT‐4 cells. The effect of the conjugates against HIV‐1 and HIV‐2 strains increased with decreasing particle size. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Crystal orientation switching in spherulites grown from miscible blends of poly(3‐hydroxybutyrate) with cellulose tributyrate
Authors: Gazzano Massimo , Mazzocchetti Laura , Pizzoli Maria , Scandola Mariastella 
Published: August 2012

AbstractFully miscible blends over the whole composition range are obtained by melt mixing bacterial poly(3‐hydroxybutyate) (PHB) and tri‐substituted cellulose butyrate [cellulose tributyrate (CTB)]. Blends containing up to 50 wt % CTB are partially crystalline. Isothermal crystallization experiments show formation of PHB spherulites that grow until impingement. Depending on composition, radial growth rate is either constant or it suddenly increases in a very unusual manner leading to peculiar morphologies. In the latter case, in concomitance to the crystal growth acceleration, the sign of birefringence changes and rotation of the PHB unit cell orientation is observed. These results are discussed in terms of the influence of both composition and Tc on the relative crystallization kinetics of the two blend components. A strong effect played by the not yet crystallized CTB component that in the presence of the highly mobile PHB component forms a liquid crystal‐like phase is proposed. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Rate‐, temperature‐, and structure‐dependent yield kinetics of isotactic polypropylene
Authors: van Erp T. B. , Cavallo D. , Peters G. W. M. , Govaert L. E. 
Published: August 2012

AbstractThe influence of cooling rate on the structure and resulting mechanical performance is explored for a set of isotactic polypropylenes with varying molecular weight, insertion of counits, and addition of a nucleating agent. A continuous variation of crystal type (α–mesomorphic phase competition) and structural features is obtained with cooling rate. These variations are discussed in relation to the strain rate‐ and temperature‐dependent yield stress and time‐to‐failure kinetics. The deformation kinetics, characterized by constant activation volumes and energies in the Ree–Eyring theory, prove to be the same for various structures. Differences in thermal history are solely captured by two rate constants that are function of the structure. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Molecular solubility and hansen solubility parameters for the analysis of phase separation in bulk heterojunctions
Authors: Duong Duc T. , Walker Bright , Lin Jason , Kim Chunki , Love John , Purushothaman Balaji , Anthony John E. , Nguyen Thuc‐Quyen 
Published: August 2012

AbstractAlthough the fabrication procedures for bulk heterojunction (BHJ) solar cells are routinely optimized to accommodate new organic materials, the influence of solvent properties and cohesive forces on the film‐forming process and the self‐assembly of donor and acceptor molecules on the nanoscale are poorly understood. In this study, we measure the solubility of a variety of organic semiconductors in a range of solvents and calculate cohesive forces including dispersion forces, dipole interactions, and hydrogen bonding via Hansen Solubility Parameters (HSPs). HSPs were calculated by measuring the solubilities of various organic semiconductors in 27 solvents and the influence of solvent identity on film morphology of different BHJ mixtures was explored via atomic force microscopy (AFM). The possibility of correlations between HSPs and film morphology was considered; however, it is apparent that the HSP values alone do not play a critical role in determining the morphology of the films of conjugated polymers and molecules. This collection of solubility data constitutes the first of its type for organic semiconducting materials, and may act as a useful reference for the organic semiconductor community to aid in the understanding and selection of solvents for donor–acceptor BHJ mixtures. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Parameters affecting the luminescence of nanodiamond particles: Quantum chemical calculations
Authors: Kovalenko A. , Petráková V. , Ashcheulov P. , Záliš S. , Nesládek M. , Kraus I. , Kratochvílová I. 
Published: August 2012

AbstractIn this article, theoretical interpretation and prediction of the optical properties of nanodiamond (ND) particles', containing various luminescence centers, was made. Particularly, nitrogen, and chromium atoms embedded into the diamond crystal lattice were modeled. In the case of nitrogen centers containing ND particles, the effect of various surface terminations (hydrogen and/or oxygen, fluorine) was also studied. To get a qualitative better understanding of the complicated and specific process of ND particles, luminescence using density functional theory, were modeled processes and states influencing the luminescence of ND particles.
Two‐dimensional thermoluminescence of CVD diamond films
Authors: Karczmarska Agnieszka , Mitura‐Nowak Marzena , Kulij Marta , Marczewska Barbara , Marszałek Marta 
Published: August 2012

AbstractDiamond crystals can be used as thermoluminescent (TL) detectors due to their high sensitivity to the ionizing radiation. Passive diamond detectors exposed to the radiation cumulate the dose in their trap structure, which can be read out by a photomultiplier during heating of the diamond. The replacement of photomultiplier by a CCD camera gives the possibility to register the dose distribution over the surface of a CVD wafer and control the homogeneity of the diamond layer. The aim of the work was to use two‐dimensional (2‐D) TL system consisting of a planar reader with a CCD camera for the quick estimation of the homogeneity of CVD diamond surface prepared in different conditions. Diamond films were deposited using a microwave plasma enhanced chemical vapor deposition method with methane–hydrogen–oxygen gas mixture. Growth conditions such as gas composition mixture and substrate temperature strongly affect morphology and structure of polycrystalline diamond, which results in different local TL properties. Samples were exposed to Co‐60 gamma radiation. The appearance of inhomogeneous dose distribution of the CVD diamond wafers was correlated with structure, morphology and phase purity. Diamond layers were investigated by scanning electron microscopy, Raman spectroscopy and X‐ray diffraction. Large area 2‐D TL system seems to be a promising tool for testing CVD diamonds and can be the basis for the analysis of the diamond coatings for TL synthesized in conditions, which provide reproducibility.
DIEL CHANGES OF DISSOLVED ORGANIC MATTER IN STREAMS OF VARYING WATERSHED LAND USE
Authors: Wilson H. F. , Xenopoulos M. A. 
Published: August 2012

ABSTRACTWe examined diel changes in dissolved organic matter (DOM) under summer low‐flow conditions for six streams selected across a gradient of agricultural land use intensity (21%–73% cropland). Trends in concentration [dissolved organic carbon (DOC) concentration] and optical properties of DOM showed a high degree of synchrony. During a 24‐h period, DOC changed by between 2.9 and 4.3 mg L−1. For all sites, the highest DOC was observed during dark periods and the lowest concentration during light periods. DOM sampled during daylight hours was more complex (humic) as determined using specific absorbance. DOM source, measured using fluorescence spectroscopy, usually varied during the 24‐h period, but few similarities in temporal fluorescence trends were identified between sites. Human landscape alterations appear to have little direct influence on the temporal nature of diel DOM dynamics in our study region. However, our results indicate that landscape characteristics are likely more broadly important in defining the magnitude temporal change in DOC. Woodland areas were negatively correlated with early afternoon DOC (r2 = 0.89, p = 0.005), positively correlated with diel percent change in DOC (r2 = 0.87, p = 0.007) and positively with diel change in discharge (r2 = 0.64, p = 0.054). Together, these results indicate the likely influence of differing riparian transpiration rates and changing subsurface inputs on DOC loading. Reduced DOC and discharge rates during daylight hours resulted in a mean underestimation of DOC export rate by 61% for early afternoon versus early morning sampling. Variation in the dominant source of DOM entering theses streams was strongly related to agricultural land use, and DOM in high cropland streams was more microbially derived. In addition, high cropland streams also exhibited the lowest minimum dissolved oxygen concentrations, a pattern related to high rates of productivity at these sites. Copyright © 2012 John Wiley & Sons, Ltd.
Detecting and visualizing online dispute dynamics in replying comments
Authors: Lee Yun‐Jung , Kim Eun‐Kyung , Cho Hwan‐Gue , Woo Gyun 
Published: August 2012

SUMMARYIn Web‐based social media (blogs, Internet forums, etc.), readers express their opinions by attaching reply comments to articles and understand others' perspectives by reading these comments. On Web forums, users discuss and argue with others via reply comments. Thus, a series of comments may provide new information, particularly about disputes among participants. Unfortunately, current systems for viewing reply comments are primitive; it is hard to follow disputes and their relationships by using such systems. We examine the characteristics of disputes by using reply comments and propose a novel system for automatically detecting disputes and their relationships among a large set of reply comments. This paper defines a dispute section as a series of comments where the dispute index is sufficiently high. The dispute index is determined using an exponential model with three control parameters. Next, the dispute relationship can be defined according to a pair of arguing commenters. The basic concept is to exploit the order of comment posting times and comment writer information when detecting dispute sections because the comments tend to appear in ordered pairs. The proposed system detects dispute sections and visualizes them according to dispute relationships among commenters, enabling users to appreciate the controversial structure of comments. To test the performance of our system, we constructed a dataset containing comment sequences associated with 40 articles collected from an Web forum. We constructed the set of dispute comments manually. We found that the detection accuracy of our system for disputes and their relationships were 83% and 78% on average. Copyright © 2012 John Wiley & Sons, Ltd.
Combining weak and strong mutation for a noninterpretive Java mutation system
Authors: Kim Sang‐Woon , Ma Yu‐Seung , Kwon Yong‐Rae 
Published: August 2012

SUMMARYBecause of the computationally expensive cost of mutation testing, automated system support is indispensable for conducting mutation testing. Mutation systems can be classified into interpretive and noninterpretive, but recent systems are noninterpretive. Weak mutation is a well‐known cost reduction method of mutation testing, but it is not directly applicable to noninterpretive mutation systems. To address the problem and take advantage of the efficiency of weak mutation, this paper presents a combined weak and strong mutation for noninterpretive Java mutation systems. The new term ‘serialmutant’ is defined as a specialized program to conduct weak mutation against all mutants in an execution and report only weakly killed mutants as strong mutation candidates. Then strong mutation is conducted only for those reported mutants. The paper also describes an implementation based on a previous Java mutation tool, MuJava. Method‐level mutation operators for Java are also redesigned. Experimental results show that the proposed approach efficiently improves the mutation cost in a noninterpretive mutation system. Copyright © 2012 John Wiley & Sons, Ltd.
Design of Novel Binuclear Phthalocyanines formed by Dioxyphenyl Bridges: Synthesis and Investigation of Thermal and Antioxidant Properties
Authors: Ağırtaş M. Salih , Gümüş İlkay , Okumus Veysi , Dundar Abdurrahman 
Published: August 2012

Abstract4, 4′‐(1, 4‐Phenylenebis(oxy)diphthalonitrile was synthesized by reaction of hydroquinone with 4‐nitrophthalonitrile. Binuclear metallophthalocyanines 2–4 were obtained by the reaction between 4, 4′‐(1, 4‐phenylenebis(oxy)diphthalonitrile and 4‐(benzo [d] 1,3 dioxol‐5‐ylmethoxy)phthalonitrile in the presence of metal salts. These new compounds were characterized by using elemental analysis, FTIR, 1H‐NMR and UV/Vis spectroscopic data. Thermal properties of phthalocyanines 2‐4 were investigated by TG and DTA. In addition, antioxidant properties of compounds II, 3 and 4 were investigated. Their radical‐scavenging capacity and chelating effects was fully studied. The maximum 1, 1‐diphenyl‐2‐picrylhydrazyl radicals (DPPH) were obtained from compound 3. Chelating effects on ferrous ions were 91.6 % at concentration of 100 mg L–1 with compound II.
Synthesis and Characterization of Iron(II) Thiocyanate Complexes with Derivatives of the Tris(pyridine‐2‐ylmethyl)amine (tmpa) Ligand
Authors: Kisslinger Sandra , Kelm Harald , Zheng Sipeng , Beitat Alexander , Würtele Christian , Wortmann Ramona , Bonnet Sylvestre , Herres‐Pawlis Sonja , Krüger Hans‐Jörg , Schindler Siegfried 
Published: August 2012

AbstractAbstract. A series of iron(II) dithiocyanate complexes containing the tripodal ligands L, [Fe(L)(NCS)2] (with L = 6‐Me2tmpa, 6‐Me2pmea, 6‐Me2‐Me2uns‐penp, 6‐Me2‐uns‐penp, Me2uns‐penp, imine‐uns‐penp and TMG‐uns‐penp), analogous to the known SCO complex[Fe(tmpa)(NCS)2] were prepared and investigated. It was possible to structurally characterize [Fe(6‐Me2pmea)(NCS)2], [Fe(6‐Me2‐Me2uns‐penp)(NCS)2], [Fe(Me2uns‐penp)(NCS)2], [Fe(imine‐uns‐penp)(NCS)2] and [Fe(TMG‐uns‐penp)(NCS)2]. Magnetic susceptibility and Mößbauer measurements showed that all seven compounds maintain their high‐spin states between 300 and 5 K.
Polychalcogenide Anions: Structural Diversity and Ligand Versatility
Authors: Sheldrick William S. 
Published: August 2012

AbstractThe structures and ligand binding modes of polychalcogenide anions are reviewed in this article. Participation in hypervalent 3c‐4e bonds and/or weaker secondary np2 → nσ* bonds leads to a strikingly more diverse homopolytaomic anion chemistry for selenium and tellurium in comparison to sulfur, for which only unbranched chain anions Sn2– with n = 2–9 have been reported. Trapped S2·– and S3·– radicals are responsible for the characteristic colours of the ultramarine pigments and S3·– is the dominant sulfur species at the high temperatures and pressures of deep metamorphic settings. Hypervalent linear TeTe24–, T‐shaped TeTe34– and square‐planar TeTe46– units generate a remarkable variety of structural motifs and connectivity patterns for 1 to 3D polytelluride anions. Electron‐deficient polytelluride sheets are, however, prone to periodic spatial modifications of their charge density (CDWs) with a lower total free energy, whose formation is driven by nesting effects in the electronic band structure causing Fermi surface instabilities. Polychalcogenide ligands augment the typical terminal and bridging coordination modes of monoatomic chalcogenide anions through their ability to participate in chelation, side‐on and combination binding modes. In addition to the electrical conductivity and thermoelectric energy conversion properties of the polytellurides, potential applications of the polychalcogenides range from the manufacture of synthetic zeolite pigments and ion‐exchangeable polysulfide aerogels to NIR‐emissive lanthanide polyselenides with high quantum efficiency.
Optical Properties of the Orchid Colored Silver(II) Fluoride Cs2AgF4
Authors: Tong Jianwei , Köhler Jürgen , Simon Arndt , Lee Changhoon , Whangbo Myung‐Hwan 
Published: August 2012

AbstractOrchid colored powder samples of Cs2AgF4 were prepared by a solid state reaction from CsF and AgF2. The diffuse reflectance spectrum of a powder sample of Cs2AgF4 was measured in the UV/Vis region. It shows three broad bands, two in the visible‐light region at 650 nm, 500 nm and one in the UV region at 259 nm. The bands are assigned to F 2p → Ag 4d and Ag 4d → Ag 4d transitions. The optical band gap for Cs2AgF4 determined from the UV/Vis diffuse reflectance spectrum is approx. 2.17 eV. In order to interpret the observed absorptions, the theoretical absorption spectrum of Cs2AgF4 was obtained from density functional calculations.
Risk factors for relaparotomy after cesarean delivery
Authors: Levin Ishai , Rapaport Avital S. , Satzer Liat , Maslovitz Sharon , Lessing Joseph B. , Almog Benny 
Published: August 2012

AbstractObjectiveTo identify risk factors for relaparotomy after cesarean delivery.MethodsCases of exploratory laparotomy at Lis Maternity Hospital, Tel Aviv, Israel, following cesarean delivery between 2000 and 2010 were reviewed retrospectively. Each case in the study group was matched randomly with 5 control cases in which the patient underwent cesarean delivery only. Demographic and clinical data before and during the primary procedure were compared.ResultsTwenty‐eight (0.2%) of 17 482 cesarean deliveries were followed by exploratory relaparotomy. Significant differences between the study and the control (n = 140) groups were found in: placental abruption as an indication for cesarean (17.8% vs 0.6%; P = 0.004); duration of primary operation (45.3 ± 21.1 vs 29.9 ± 11.8 minutes; P = 0.007; 95% CI, 5.1–19.2); and experience of chief surgeon (10.1 ± 1.6 vs 5.8 ± 0.4 years; P = 0.02; 95% CI, 0.0–5.0). Findings during relaparotomy were: abdominal wall bleeding/hematoma (n = 4 [14.2%]); uterine scar bleeding (n = 4 [14.2%]); retroperitoneal bleeding (n = 1 [3.5%]); adhesions causing bowel obstruction (n = 1 [3.5%]); and uterine scar gangrene (n = 1 [3.5%]). There were no findings for 17 (60.7%) patients.ConclusionThe incidence of relaparotomy following cesarean was 0.2% (1 per 624 cesarean deliveries). Significant risk factors were placental abruption and longer operative time.
Does agency age matter in administrative reform?: Policy autonomy and public management in Swedish agencies
Authors: Niklasson Birgitta , Pierre Jon 
Published: August 2012

AbstractThis paper looks at the policy autonomy of different “generations” of agencies in Sweden. Taking a historical institutional perspective, we argue that the policy autonomy of public agencies is related to the dominant political and administrative trends at the time when the agency was first created, i.e. that institutional relations created at that formative moment tend to persist. In the Swedish context, one such trend is of particular importance; the managerial trend that started in 1963 with the Program Budgeting (PB) reform. This was an institutional reform that presented a paradigm shift in Swedish public administration. This reform was reinforced in the 1990s by the New Public Management (NPM) reform, which introduced new instruments and measures consistent with the managerial paradigm previously introduced by the PB reform. This managerial trend aimed at limiting agencies’ policy autonomy. Thus, we hypothesise that (1) agencies founded before the PB reform will enjoy more extensive policy autonomy than agencies founded during or after this reform and (2) there will be no such difference between agencies founded before and after the NPM reform. These hypotheses are tested on empirical data consisting of a web survey in which 157 Swedish agencies have stated to what extent they perceive that they enjoy policy autonomy. The results confirm both our hypotheses, thus demonstrating the importance of considering the scope of institutional change when analysing and comparing the effects of administrative reforms in different countries.