bluuebunny/crossref_metadata_2025 huggingface dataset:
Encapsulation Studies of Cationic Gold Complexes within a Self‐Assembled Hexameric Resorcin[4]arene Capsule
Authors: Adriaenssens Louis , Escribano‐Cuesta Ana , Homs Anna , Echavarren Antonio M. , Ballester Pablo
Published: February 2013

As the field of supramolecular catalysis develops, a sound fundamental understanding of the catalytic assemblies used will be essential. There is a lack of knowledge regarding systems based on transition‐metal catalysts as guests of supramolecular capsules. We investigate the inclusion behavior of gold complexes based on well‐known cationic Au(I) catalysts within a self‐assembled hexameric resorcin[4]arene capsule. The results shed light on the nature of the encapsulated species and the way in which those species are encapsulated. We introduce an encapsulation methodology that functions through the transient introduction of an excess of water. Through small modifications in the encapsulation methodology, we show that the inclusion process can be controlled to give different encapsulated species stemming from the same gold(I) precursor.
Synthesis and Solid‐State Structures of 6,13‐Bis(trifluoromethyl)‐ and 6,13‐Dialkoxypentacene
Authors: Schwaben Jonas , Münster Niels , Breuer Tobias , Klues Michael , Harms Klaus , Witte Gregor , Koert Ulrich
Published: February 2013

6,13‐Disubstituted pentacenes were synthesized. Their electrochemical and optical properties, in addition to their packing motifs in the solid state, were determined. Treatment of pentacenequinone with TMSCF3 (Ruppert's reagent) and deprotection led to 6,13‐bis(trifluoromethyl)pentacene‐6,13‐diol, which was aromatized to 6,13‐bis(trifluoromethyl)pentacene by using PBr3. 6,13‐Dialkoxypentacenes were accessible by alkylation of the corresponding hydroquinopentacenes by using dialkyl sulfates. 6,13‐Bis(trifluoromethyl)pentacene and 6,13‐dimethoxypentacene exhibit slipped face‐to‐face π stacking in the solid state, whereas 6,13‐diethoxypentacene forms pairs of π‐stacking molecules in the solid state.
L‐Phototryptophan
Authors: Wartmann Thomas , Lindel Thomas
Published: February 2013

Phototryptophan is a new photoactivatable amino acid designed to be incorporated into tryptophan‐containing peptides for photoaffinity labeling. The synthesis of phototryptophan starts from 6‐bromoindole with the installation of an 1‐azi‐2,2,2‐trifluoroethyl moiety, followed by microwave‐assisted condensation with serine under mild conditions. Separation of theN‐acetylated enantiomers was possible by employingAspergillusaminoacylase. Differential scanning calorimetry showed that phototryptophan is thermally stable up to 100 °C. Boc‐L‐Phototryptophan was used to assemble a diazirine analog of the marine natural product hemiasterlin.
SEDIMENT-ASSOCIATED PESTICIDES IN AN URBAN STREAM IN GUANGZHOU, CHINA: IMPLICATION OF A SHIFT IN PESTICIDE USE PATTERNS
Authors: Li Huizhen , Sun Baoquan , Lydy Michael J. , You Jing
Published: February 2013

Pesticide use patterns in China have changed in recent years; however, the study of the environmental fate of current-use pesticides (CUPs) and their ecotoxicological significance in aquatic ecosystems is limited. In the present study, sediments were collected from an urban stream in the Chinese city of Guangzhou. Sediment-associated legacy organochlorine pesticides and CUPs—including organophosphates, pyrethroids, fipronil, and abamectin—were analyzed. Additionally, the relative toxicity of the sediments was evaluated with 10-d bioassays using Chironomus dilutus. Fifteen of 16 sediments collected from the stream were acutely toxic to C. dilutus, with 81% of the samples causing 100% mortality. Abamectin, fipronil, and pyrethroids (mainly cypermethrin) were identified as the principal contributors to the noted toxicity in the midges, with median predicted toxic units of 1.63, 1.63, and 1.03, respectively. Sediments taken from downstream sites, where residential and industrial regions were located, had elevated CUP concentrations and sediment toxicity compared with upstream sites. The present study is the first of its kind to link sediment CUPs, fipronil, and abamectin concentrations with toxicity in urban streams in China with a focus on shifting pesticide usage patterns. Environ. Toxicol. Chem. 2013;32:1040–1047. © 2013 SETAC
COMPARISON OF SPECIES SENSITIVITY DISTRIBUTIONS BASED ON POPULATION OR INDIVIDUAL ENDPOINTS
Authors: Beaudouin Rémy , Péry Alexandre R.R.
Published: February 2013

Species sensitivity distributions (SSDs) developed from individual and population endpoints were compared based on simulations and a case study. The simulations were performed with five invertebrate species accounting for the diversity of benthic macroinvertebrate communities in large European lowland rivers and for five benthic invertebrates used as laboratory species. Population growth rate 10% effective concentration (EC10) values were, in most of the simulations, higher than the lowest of the EC10 values at the individual level. However, for the set of ecologically representative species, the fifth percentile level of this distribution (HC5) was more protective for population endpoints than for individual endpoints. This was the opposite for the set of laboratory species. Population and individual SSDs were also compared based on existing data on Cu for the five laboratory invertebrate species. In this case, the calculated population HC5 value was almost twice the individual value, and the authors showed much reduced variability between species sensitivities at population level compared with individual level. They conclude that population-based HC5 would generally be more protective than individual-based HC5. However, the change of level could reveal higher homogeneity at population level than at individual level, supporting the use of population-based HC5 to avoid overprotection. The authors thus advise the derivation of population-based HC5, as soon as it is possible, to derive such value with a relevant panel of species. Environ. Toxicol. Chem. 2013;32:1173–1177. © 2013 SETAC
Oxygen and sulfur dioxide additions to Sauvignon blanc must: effect on must and wine composition
Authors: Coetzee Carien , Lisjak Klemen , Nicolau Laura , Kilmartin Paul , du Toit Wessel Johannes
Published: February 2013

Sauvignon blanc wines often have complex aromatic profiles with flavours ranging from herbaceous to tropical. The formation of volatiles during fermentation is critical for the aromatic bouquet of a wine. Oxygen and sulfur dioxide additions to the must can influence the formation of these compounds. However, the effect of different, controlled oxygen and sulfur dioxide additions to Sauvignon blanc must and the changes it induces in the corresponding wines has not been investigated in detail. The present study evaluated how controlled oxygen and sulfur dioxide additions to Sauvignon blanc must affects the levels of volatile and non‐volatile compounds, including the methoxypyrazines, volatile thiols, esters, alcohols, fatty acids, monoterpenes, glutathione and phenolics. It was evident that the presence of sulfur dioxide resulted in wines with higher concentrations of certain compounds. Copyright © 2013 John Wiley & Sons, Ltd.
Effect of Porosity in Catalyst Layers on Direct Methanol Fuel Cell Performances
Authors: Lee Y. , Kim T. K. , Choi Y. S.
Published: February 2013

Effects of porosity of catalyst layers (CLs) on direct methanol fuel cell (DMFC) performances are investigated using silicon dioxide (SiO2) particles as a pore former. The pore size and volume of CLs are controlled by changing the size and content of SiO2. As the size of pore formed by removal of SiO2 increases, DMFC performances are enhanced. The augmentation in performances can be explained by facilitation of fuel transport to catalyst particles, increase of utilization efficiency of catalysts, diminishment in methanol crossover, reduction in activation loss and facilitation of water discharging out of CLs of cathode due to the controlled porosity in CLs. The enhanced fuel transport, accessibility of fuels to Pt catalyst surface, is proved by the active areas of Pt catalyst. In addition to the active area of Pt catalyst, porous CLs exhibit a decline in methanol crossover, leading to increase of open circuit voltage (OCV). The porous CLs also show improvements in activation loss due to high porosity, causing enhancement in DMFC performances. In aspect of pore volume contribution to cathode performance, the SiO2 content is optimized. Based on the DMFC performances, it can be suggested that the optimum conditions of SiO2 are 500 nm in size and 20 wt.% in content. The porosity effect on both electrodes appears as follows: the pores in cathode are more effective on DMFC performances (55.5%) than those of anodes (44.5%) based on the maximum power of DMFC, indicating that the pores in CLs facilitate removal of water from electrodes.
Break‐down of Losses in High Performing Metal‐Supported Solid Oxide Fuel Cells
Authors: Kromp A. , Nielsen J. , Blennow P. , Klemensø T. , Weber A.
Published: February 2013

A detailed electrochemical impedance study with the help of the distribution of relaxation times (DRT) method and a subsequent CNLS‐fit enabled us to quantitatively analyze the different loss contributions in the cell: the ohmic resistance and the polarization processes related to the gas diffusion in the metal support, the electrochemical fuel oxidation at the anode and the oxygen reduction in the mixed ionic electronic conducting cathode. An additional process with a rather high relaxation frequency was attributed to the formation of insulating interlayers at the cathode/electrolyte‐interface. Based on these results, selective measures to improve performance and stability, such as (i) PVD‐deposited CGO buffer layer preventing solid state reaction between cathode and the zirconia‐based electrolyte, (ii) LSC‐CGO based in‐situ sintered cathodes and (iii) reduced corrosion of the metal support, were adopted and validated.
Sulfur Poisoning of Anode‐Supported SOFCs under Reformate Operation
Authors: Weber A. , Dierickx S. , Kromp A. , Ivers‐Tiffée E.
Published: February 2013

The impact of sulfur‐poisoning on reforming chemistry and electrochemistry of anode‐supported solid oxide fuel cells is analyzed via electrochemical impedance spectroscopy. Different types of anode supported cells are operated in hydrogen/steam – as well as simulated reformate – (H2 + H2O + CO + CO2 + N2) fuels containing 0.1–15 ppm of H2S. A detailed analysis of impedance spectra by the distribution of relaxation times (DRT) and a subsequent complex nonlinear least squares (CLNS) fit separates the impedance changes taking place at the anode and the cathode. Two main features were detected in the DRT, a decreased reaction rate of the electrochemical hydrogen oxidation and a deactivation of the catalytic conversion of CO via the water‐gas shift reaction. During the first exposure of the cell to a H2S‐containing fuel, an enhanced degradation is observed. The degradation rate increases several hours after H2S was added to the fuel and decreases after the poisoning is completed. The polarization resistance increased by a factor of 2–10, depending on H2S‐content, fuel composition and cell type. Comparing the temporal characteristics of the polarization resistance of two different anode supported cells, it could be shown that the accumulated H2S‐amount divided by the Ni‐surface area inside the anode substrate and anode functional layer determine the onset of the degradation.
Degradation of a High Performance SOFC Cathode by Cr‐Poisoning at OCV‐Conditions
Authors: Kornely M. , Menzler N. H. , Weber A. , Ivers‐Tiffée E.
Published: February 2013

In this work we investigate the effect of Cr‐poisoning at OCV‐condition by means of electrochemical impedance spectroscopy (EIS). The anode‐supported cell (ASC) is operated in Cr‐free environment for the first 70 h of the cell test at 800 °C supplying air to the cathode and a varying mixture of H2O/H2 to the anode. The performance of the cell is determined by current‐voltage (CV) measurement after the start up. After an operating time of 70 h in the absence of chromium species a Cr‐source was switched on by passing the oxidant (air) through a Crofer22APU powder bed. In order to determine the degradation caused by Cr‐poisoning electrical impedance spectra are collected at every 29 h of operating time. After further 275 h at OCV‐condition in the presence of Cr‐source another CV‐curve is measured. A detailed analysis of the measured impedance spectra by the distribution of relaxation times (DRT) enables a separation of the cathode polarization resistance. During the Cr‐free operation the cathode polarization shows a constant value. After the Cr‐source is switched on a strong increase of the cathode polarization resistance is observed. This unique result shows clearly that Cr‐poisoning of an LSM/8YSZ‐cathode already takes place at OCV‐condition.
Analytical solutions of the potential vorticity invertibility principle
Authors: Masarik Matthew T. , Schubert Wayne H.
Published: February 2013

We define the f‐plane, y‐independent, potential vorticity (PV) invertibility principle as a coupled pair of first‐order partial differential equations relating the balanced wind and mass fields to the known PV. Analytical solutions of this invertibility principle are derived for cases in which an isolated PV anomaly is confined within a region of the vertical plane. The solutions aid in understanding the dynamics of low‐latitude PV intrusions whose associated cloud patterns are often referred to as cloud surges, or moisture bursts, and whose flow patterns are often referred to as tropical upper tropospheric troughs. The existence of such tongues of high PV air intruding into the upper troposphere is documented using reanalysis data from the “Year” of Tropical Convection data set. The solutions illustrate the phenomenon of isentropic upglide below an upper tropospheric positive anomaly in PV. They also quantify how the partitioning of PV between absolute vorticity and static stability depends on the shape and strength of the PV anomaly. With slight modifications, the solutions apply to the problem of determining the balanced flow induced by a surface temperature anomaly, which is equivalent to a very thin layer of infinite PV at the surface. Through numerical solutions of the fully nonlinear invertibility principle we provide justification for the anelastic‐type approximation used in the analytical theory.
Atmospheric component of the MPI‐M Earth System Model: ECHAM6
Authors: Stevens Bjorn , Giorgetta Marco , Esch Monika , Mauritsen Thorsten , Crueger Traute , Rast Sebastian , Salzmann Marc , Schmidt Hauke , Bader Jürgen , Block Karoline , Brokopf Renate , Fast Irina , Kinne Stefan , Kornblueh Luis , Lohmann Ulrike , Pincus Robert , Reichler Thomas , Roeckner Erich
Published: February 2013

ECHAM6, the sixth generation of the atmospheric general circulation model ECHAM, is described. Major changes with respect to its predecessor affect the representation of shortwave radiative transfer, the height of the model top. Minor changes have been made to model tuning and convective triggering. Several model configurations, differing in horizontal and vertical resolution, are compared. As horizontal resolution is increased beyond T63, the simulated climate improves but changes are incremental; major biases appear to be limited by the parameterization of small‐scale physical processes, such as clouds and convection. Higher vertical resolution in the middle atmosphere leads to a systematic reduction in temperature biases in the upper troposphere, and a better representation of the middle atmosphere and its modes of variability. ECHAM6 represents the present climate as well as, or better than, its predecessor. The most marked improvements are evident in the circulation of the extratropics. ECHAM6 continues to have a good representation of tropical variability. A number of biases, however, remain. These include a poor representation of low‐level clouds, systematic shifts in major precipitation features, biases in the partitioning of precipitation between land and sea (particularly in the tropics), and midlatitude jets that appear to be insufficiently poleward. The response of ECHAM6 to increasing concentrations of greenhouse gases is similar to that of ECHAM5. The equilibrium climate sensitivity of the mixed‐resolution (T63L95) configuration is between 2.9 and 3.4 K and is somewhat larger for the 47 level model. Cloud feedbacks and adjustments contribute positively to warming from increasing greenhouse gases.
Arctic sea‐ice evolution as modeled by Max Planck Institute for Meteorology's Earth system model
Authors: Notz Dirk , Haumann F. Alexander , Haak Helmuth , Jungclaus Johann H. , Marotzke Jochem
Published: February 2013

We describe the evolution of Arctic sea ice as modeled by the Max Planck Institute for Meteorology's Earth System Model (MPI‐ESM). The modeled spatial distribution and interannual variability of the sea‐ice cover agree well with satellite observations and are improved relative to the model's predecessor ECHAM5/MPIOM. An evaluation of modeled sea‐ice coverage based on sea‐ice area gives, however, conflicting results compared to an evaluation based on sea‐ice extent and is additionally hindered by uncertainties in the observational record. Simulated trends in sea‐ice coverage for the satellite period range from more strongly negative than observed to positive. The observed evolution of Arctic sea ice is incompatible with modeled internal variability and probably caused by external forcing. Simulated drift patterns agree well with observations, but simulated drift speed is generally too high. Simulated sea‐ice volume agrees well with volume estimates of the PIOMAS reanalysis for the past few years. However, a preceding Arctic wide decrease in sea‐ice volume starts much earlier in MPI‐ESM than in PIOMAS. Analyzing this behavior in MPI‐ESM's ocean model MPIOM, we find that the modeled volume trend depends crucially on the specific choice of atmospheric reanalysis forcing, which casts some doubt on the reliability of estimates of volume trends. In our CMIP5 scenario simulations, we find a substantial delay in sea‐ice response to increasing CO2 concentration; a seasonally ice‐free Arctic can result for a CO2 concentration of around 500 ppm. Simulated winter sea‐ice coverage drops rapidly to near ice‐free conditions once the mean Arctic winter temperature exceeds −5°C.
Phenotypic redifferentiation and cell cluster formation of cultured human articular chondrocytes in a three‐dimensional oriented gelatin scaffold in the presence of PGE2 ‐ first results of a pilot study
Authors: Brochhausen Christoph , Sánchez Natalia , Halstenberg Sven , Zehbe Rolf , Watzer Bernhard , Schmitt Volker H. , Hofmann Alexander , Meurer Andrea , Unger Ron E. , Kirkpatrick Charles James
Published: February 2013

Modern tissue engineering strategies comprise three elemental parameters: cells, scaffolds and growth factors. Articular cartilage represents a highly specialized tissue which allows frictionless gliding of corresponding articulating surfaces. As the regenerative potential of cartilage is low, tissue engineering‐based strategies for cartilage regeneration represent a huge challenge. Prostaglandins function as regulators in cartilage development and metabolism, especially in growth plate chondrocytes. In this study, it was analyzed if prostaglandin E2 (PGE2) has an effect on the phenotypic differentiation of human chondrocytes cultured in a three‐dimensional (3D) gelatin‐based scaffold made by directional freezing and subsequent freeze‐drying. As a result, it was clearly demonstrated that low doses of PGE2 revealed beneficial effects on the phenotypic differentiation and collagen II expression of human articular chondrocytes in this 3D cell culture system. In conclusion, PGE2 is an interesting candidate for tissue engineering applications since it represents an already well‐studied molecule which is available in pharmaceutical quality. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Mohr's Salt Hexahydrate: A Novel, Cheap and Powerful Reagent for Green Synthesis of Biscoumarins on Water
Authors: Khodabakhshi Saeed , Baghernejad Mojtaba
Published: February 2013

A new and convenient method for the synthesis of biscoumarins based on the condensation of 4‐hydroxycoumarin and aromatic aldehydes in the presence of Mohr's salt hexahydrate (ferrous ammonium sulfate hexahydrate) as a novel catalyst on water is developed. This method has advantages such as the use of inexpensive and available reagent, avoidance of organic solvents, short reaction times, and high product yields.
Reactions of Iron Acyl Chalcogenide Clusters with Electrophiles: Reactivity Comparison and Theoretical Calculations
Authors: Shieh Minghuey , Chu Yen‐Yi , Chi Hsin‐Hung , Chen Horng‐Sun , Hsing Kai‐Jieah , Huang Chung‐Yi
Published: February 2013

The reactions of two types of EFe3‐based acyl clusters [EFe3(CO)9C(O)C(H)CCH2)]− (E = S, 1; Se, 2; Te, 3) with different electrophiles have been systematically studied and compared. When the sulfur‐substituted allylcarbonyl Fe3‐cluster [Fe3(CO)9{μ3‐η2:η1:η3‐C(O)CHC(S)CH2}]− (1) was treated with CH3COCl in CH2Cl2, the Fischer‐type acyloxy carbene cluster [Fe3(CO)9{μ3‐η2:η4:η1‐C(OCOCH3)‐C(H)C(S)CH2}] (4) was obtained, along with the previously reported SC(O)C(CH3)=CH bridged Fe2‐complex [Fe2(CO)6{μ‐η2:η3‐SC(O)C(CH3)CH}] (5) and [HSFe3(CO)9]−. Similar acetylation of the allylcarbonyl SeFe3‐cluster [(μ3‐Se)Fe3(CO)9(μ3‐η1:η1:η3‐C(O)C(H)CCH2)]− (2) produced the Fe2‐carbene complex [Fe2(CO)6{μ‐η2:η3‐C(OCOCH3)C(H)C(Se)CH2}] (6) and the propyne‐bridged SeFe3‐complex [(μ3‐Se)Fe3(CO)9{μ3‐η1:η2:η1‐C(CH3)=C(H)}] (7) as well as [HSeFe3(CO)9]− and [Se2Fe3(CO)9]. However, when the analogous TeFe3‐based allylcarbonyl cluster [(μ3‐Te)Fe3(CO)9(μ3‐η1:η1:η3‐C(O)C(H)CCH2)]− (3) reacted with CH3COCl, only the fragmentation product [Te2Fe3(CO)9] was formed. Further acidification of cluster 1 with HBF4 proceeded to form complex 5 and [HSFe3(CO)9]−. Similar acidification of 2 formed the propyne‐capped complex 7, however, the protonation of 3 led to the formation of [Te2Fe3(CO)9]. Contrast to the reported reactions of 1 and 3, the reaction of 2 with [Cu(CH3CN)4][BF4] formed complex 7 and a new C(O)CH=C(Se)(CH3) bridged Fe2‐complex [Fe2(CO)6{μ‐η2:η3‐C(O)CHC(Se)(CH3)}] (8). The nature and formation of new carbene complexes 4 and 6 were further elucidated with the aid of molecular orbital calculations at the B3PW91 level of density functional theory.
Synthesis, Structure and Photoluminescence of Lanthanide Metal‐Organic Frameworks, Ln4(TDC)6(DMF)4(H2O)2, where TDC2− = thiophene‐2,5‐dicarboxylate, DMF = N,N‐dimethylformamide
Authors: Tsai Cherng‐Shiaw , Chen Wan‐Ting , Liao Ju‐Hsiou
Published: February 2013

A series of lanthanide metal‐organic frameworks, Ln4(TDC)6(DMF)4(H2O)2, where Ln = Nd (1), Sm (2), Eu (3), Gd (4), TDC2− = thiophene‐2,5‐dicarboxylate, have been synthesized at 80 °C in mixed H2O/DMF. Structural characterizations by single‐crystal X‐ray crystallography reveal that 1∼4 are isomorphous and adopt three‐dimensional frameworks which are constructed by cross‐linking Ln3+ ions with thiophene‐2,5‐dicarboxylates as bridging ligands. These frameworks feature rhomboidal channels, inside which coordinated DMF solvent molecules are located. Thermogravimetric analyses suggest solvent molecules can be removed at about ca. 340 °C. Photoluminescence studies indicate TDC2− ligand shows excellent antenna effect for the europium(III) MOF (3), which exhibits intense characteristic europium(III) emissions upon excitation at μex = 306 nm.
Synthesis, Structural Characterization and Thermal Stability of A One‐Dimensional Chain‐like Coordination Polymer, [Fe(bpno)2(NCS)3]
Authors: Chiu Hsiu‐Hui , Shen Mei‐Chi , Wang Chih‐Chieh , Lee Gene‐Hsiang , Sheu Hwo‐Shuenn
Published: February 2013

A new polymeric complex, [Fe(bpno)2(NCS)3]n (1) (bpno = 4,4′‐bipyridyl‐N,N′‐dioxide) have been synhesized and structural characterized by single crystal X‐ray diffraction. Compound 1 crystallizes in the triclinic system, space group P‐1, with chemical formula C23H16FeN7O4S3, a = 9.0738(5), b = 9.7175(5), c = 15.0329(8) Å, α = 97.668(1), β = 92.581(1) and γ = 102.441(1)°, V = 1279.1(1) and Z = 2. Structural determination reveals that the coordination environment of the iron(III) ion is distorted octahedral, bonded with three oxygen donors of three bpno and three nitrogen donors of three NCS− ligands. The bpno ligands adopt two different coodination modes, a monodentate coordination mode and a bis‐monodentate coordination mode, which links the Fe(III) ions to form a one‐dimensional (1D) zigzag chain‐like coordination polymer. Neighbouring chains are mutually connected via the C‐H···O type hydrogen bonds to form a 2D hydrogen‐bonded layered framework and then extended to a 3D supramolecular architecture via π‐π interaction between the pyridyl rings of bpno ligands and unconventional C‐H···S hydrogen bonding interactions. Compound 1 exhibits moderate thermo‐stability and keeps its crystalline forms up to 190 °C.
A novel process for the recovery of superoxide dismutase from yeast exploiting electroextraction coupled to direct sorption
Authors: Simental‐Martínez Jesús , Vennapusa Rami Reddy , Benavides Jorge , Ganeva Valentina , Galutzov Bojidar , Rito‐Palomares Marco , Fernández‐Lahore Marcelo
Published: February 2013

Background

This work presents a novel approach for the recovery and purification of superoxide dismutase (SOD; EC 1.15.1.1) produced in the yeast Kluyveromyces marxianus var. bulgaricus (NBIMCC 1984). Electroextraction was evaluated as an alternative to bead milling for SOD release. Seven anion exchange resins were studied in order to optimize SOD purification using ion exchange chromatography.

Results

Electroextraction produced an enzyme solution with a specific activity 13 times higher than with mechanical extraction, demonstrating the potential of this novel technique for the selective liberation of SOD. Regarding the anion exchange resins that were studied, Amberlite™ IRA‐96 and Q Sepharose™ XL were chosen as the best options for purifying SOD using chromatography in negative adsorption mode. The process developed, involving electroextraction, enzyme concentration and negative anion exchange chromatography, rendered a highly active and pure SOD preparation (specific activity: 2056 U mg−1 and 66‐fold purification) with an overall recovery yield of 84%.

Conclusion

The results presented herein demonstrate the potential of the process developed for the recovery and purification of SOD from the yeast Kluyveromyces marxianus var. bulgaricus (NBIMCC 1984). The preparation obtained could be used in the food industry as an antioxidant agent. © 2013 Society of Chemical Industry
Net increase of lactate and glutamate concentration in activated human visual cortex detected with magnetic resonance spectroscopy at 7 tesla
Authors: Schaller Benoît , Mekle Ralf , Xin Lijing , Kunz Nicolas , Gruetter Rolf
Published: February 2013

After the landmark studies reporting changes in the cerebral metabolic rate of glucose (CMRGlc) in excess of those in oxygen (CMRO2) during physiological stimulation, several studies have examined the fate of the extra carbon taken up by the brain, reporting a wide range of changes in brain lactate from 20% to 250%. The present study reports functional magnetic resonance spectroscopy measurements at 7 Tesla using the enhanced sensitivity to study a small cohort (n = 6). Small increases in lactate (19% ± 4%, P < 0.05) and glutamate (4% ± 1%, P < 0.001) were seen within the first 2 min of activation. With the exception of glucose (12% ± 5%, P < 0.001), no other metabolite concentration changes beyond experimental error were significantly observed. Therefore, the present study confirms that lactate and glutamate changes during physiological stimulation are small (i.e. below 20%) and shows that the increased sensitivity allows reproduction of previous results with fewer subjects. In addition, the initial rate of glutamate and lactate concentration increases implies an increase in CMRO2 that is slightly below that of CMRGlc during the first 1–2 min of activation. © 2013 Wiley Periodicals, Inc.
Human capital diversity in the creation of social capital for team creativity
Authors: Han Jing , Han Jian , Brass Daniel J.
Published: February 2013

We highlight the social aspects of team creativity by proposing that team creativity is influenced by two types of team social capital: bridging and bonding social capital. Going beyond the structural perspective, we posit that team‐level human capital diversity is one of the potential antecedents of social capital for team creativity. We suggest that network structures are formed by teammates' interactions, which are largely the result of differences in their individual characteristics. The results of an empirical study using 36 teams of MBA students showed that the interaction of team‐bridging social capital with team‐bonding social capital was positively and significantly related to team creativity. Knowledge variety and knowledge disparity had a joint effect on team‐bridging social capital, and knowledge separation was negatively related to team‐bonding social capital. Moreover, team social capital mediated the effects of knowledge diversity on team creativity. Our study has several important implications for team creativity, social networks, and diversity research. Copyright © 2013 John Wiley & Sons, Ltd.
The Passion for Knowledge: implications for its Transfer
Authors: Sié Laurent , Yakhlef Ali
Published: February 2013

Research into knowledge sharing has mainly treated knowledge from an instrumental, market‐driven perspective. On this view, research has focused on the psychological (e.g. motivation), cognitive (e.g. absorptive capacity) and social features (e.g. weak/strong ties) of the knowledge entities, the structural (formal or informal) characteristics of the organizational context and the nature of knowledge to be transferred (such as its stickiness and causal complexity). The present study seeks to suggest passion as a contingency that impacts the knowledge transfer process positively. Passion for knowledge may constitute a social bond that holds a community together. Passionate members are inclined to share their object of passion—knowledge—more readily. Our argument is based on information elicited from a number of scientific experts within the petrol industry. In their daily work, experts regard the transfer of knowledge as sine qua non of becoming expert, as interactions with others are (i) learning opportunities for themselves and (ii) as social occasions to relate to their peers and on to talk about and share stories about the object to their passion (knowledge). The contribution of the paper is thus to suggest emotional aspects (passion, attachment and interest) related to knowledge as a factor that impacts the transfer of knowledge. Finally, conclusions and implications are discussed. Copyright © 2013 John Wiley & Sons, Ltd.
Results of a 1‐year government‐funded newborn hearing screening program in Taiwan
Authors: Hsu Hsin‐Chien , Lee Fei‐Peng , Huang Hung‐Meng
Published: February 2013

Objectives/Hypothesis

To establish an ideal operative procedure of universal newborn hearing screening and to investigate whether a government‐funded program increases compliance with such screening.

Study Design

Individual cohort study.

Methods

Of the 3,373 neonates born at the Taipei City Hospital during the period August 2009 to July 2010, there were 3,361 who received hearing screening with automatic auditory brainstem response (AABR) 24 to 36 hours after birth. The cost of each procedure (US $16.70) was covered by the Taipei City Health Bureau. The control group comprised 6,582 neonates born at the same hospital during the period January 2003 to December 2004, of whom 5,749 had been screened with transient‐evoked otoacoustic emission (TEOAE). The cost of each procedure (US $26.70) was paid by the parents of each newborn.

Results

The incidence of bilateral moderate to severe hearing impairment was 0.06% (two out of 3,361) and 0.10% (six out of 5,749) in the study and the control group, respectively. The incidence of unilateral hearing impairment was 0.09% (three out of 3,361) and 0.19% (11 out of 5,749) respectively. The coverage rate of the study was significantly higher than that of the control group (99.64% vs. 87.34%, P < .001). A significant decrease of the referral rate was achieved in the study group when compared with the control group (0.95% vs. 2.82%, P < .001). The follow‐up rate of the study group was significantly higher than that of the control group (100.00% vs. 40.74%, P < .001).

Conclusions

The government‐funded AABR program resulted in markedly better parental compliance with newborn hearing screening than the self‐pay TEOAE screening program.

Level of Evidence

2b.
Association Between Length of Intubation and Subglottic Stenosis in Children
Authors: Manica Denise , Schweiger Cláudia , Maróstica Paulo José Cauduro , Kuhl Gabriel , Carvalho Paulo Roberto Antonacci
Published: February 2013

Objectives/Hypothesis:

To investigate the role of the length of intubation and other risk factors in the development of laryngeal lesions in children undergoing endotracheal intubation in an intensive care unit and to determine the incidence of subglottic stenosis (SGS).

Study Design:

Prospective study.

Methods:

Children aged from birth to <5 years admitted to the Pediatric Intensive Care Unit of Hospital de Clinicas de Porto Alegre who required endotracheal intubation for more than 24 hours were eligible. Children underwent flexible fiber‐optic laryngoscopy (FFL) after extubation. Those who presented moderate to severe abnormalities in this first examination underwent another FFL between 7 and 10 days. If lesions persisted or symptoms developed, regardless of initial findings, laryngoscopy under general anesthesia was performed.

Results:

We followed 142 children. In the first FFL, 58 children (40.8%) had moderate to severe laryngeal lesions. During follow‐up, 16 children developed SGS, representing an incidence of 11.3% (95% confidence interval, 7.1–17.5). Multivariate analysis showed that for every 5 additional days of intubation, there was a 50.3% increase in the risk of developing SGS, and for each additional sedation doses/day, there was a 12% increase in the same outcome.

Conclusions:

In this first prospective research protocol in children, we found a higher incidence of SGS than in most previous studies. The length of intubation and the need for additional sedation doses appear to be key factors for the development of SGS during endotracheal intubation.
A Bifunctional Diblock Copolymer from Consecutive RAFT Polymerizations and its Functionalization
Authors: Jiang Xiaowu , Du Xiangyang , Zhang Lifen , Cheng Zhenping
Published: February 2013

Poly(glycidyl methacrylate)‐block‐poly(4‐vinylbenzyl chloride), or P(GMA)‐b‐P(VBC), is synthesized via consecutive reversible addition‐fragmentation chain transfer (RAFT) polymerizations. Subsequent functionalization via atom‐transfer radical polymerization (ATRP) of methyl methacrylate (MMA) and styrene (St) gives rise to two functional brush‐type diblock graft copolymers, P(GMA)‐b‐(P(VBC)‐g‐P(MMA)) and P(GMA)‐b‐(P(VBC)‐g‐PS). These graft copolymers are further functionalized by a ring‐opening reaction of the P(GMA) block with diethylamine (DEA) to produce two diblock copolymer brushes, P(DEAHPMA)‐b‐(P(VBC)‐g‐P(MMA) and P(DEAHPMA)‐b‐(P(VBC)‐g‐PS (Brush‐2A). Single molecules of the copolymers are imaged by atomic force microscopy (AFM). Brush‐2A can be cast into porous membranes with well‐defined micropores from tetrahydrofuran (THF) solutions by phase inversion in an aqueous medium.
Synthesis of Folic Acid‐Containing Imidazolium Copolymers for Potential Gene Delivery Applications
Authors: Allen Michael H. , Day Kelsea N. , Hemp Sean T. , Long Timothy E.
Published: February 2013

Folic acid conjugation onto poly(1‐vinylimidazole) generates imidazolium copolymers for potential receptor‐mediated nonviral gene delivery. Homopolymer quaternization with various tBoc‐protected bromoalkylamines imparts a permanent charge for DNA complexation. Incorporation of primary amine groups provides a site for folic acid conjugation onto imidazolium copolymers. DNA binding, cytotoxicity, and in vitro transfection in HeLa cells reveal structure–property–transfection relationships for the imidazolium copolymers. Luciferase expression assays establish that primary amine conjugation onto imidazolium copolymers up to 30 mol% fails to improve transfection efficiency. In sharp contrast, incorporation of folic acid onto the copolymers improves transfection efficiency 250‐fold.

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Nanostructured Silica/Wheat Gluten Hybrid Materials Prepared by Catalytic Sol–Gel Chemistry
Authors: Türe Hasan , Blomfeldt Thomas O. J. , Gällstedt Mikael , Hedenqvist Mikael S. , Farris Stefano
Published: February 2013

The main physicochemical properties of nanostructured silica/wheat gluten hybrid composites are presented. The extraction experiments suggest that the protein phase is intimately encased within the silica matrix, with silica–protein interactions driven by hydrogen bonding, as indicated by IR spectra. Spectroscopic results also show that silica induces a higher degree of constraint of the wheat gluten matrix, despite less aggregation. Moisture diffusion properties of the hybrid materials are investigated by a combined “desorption/sorption” approach. While the reduction of the moisture diffusivity in the presence of silica can be described by the geometrical impedance of a “sintered” porous solid, a time‐dependent relaxation/restructuring of the composite apparently occurs during the sorption‐desorption cycle.

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On a classification of theories without the independence property
Authors: Verbovskiy Viktor
Published: February 2013

A theory is stable up to Δ if any Δ‐type over a model has a few extensions up to complete types. We prove that a theory has no the independence property iff it is stable up to some Δ, where each \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\varphi (x;\bar{y}) \in \Delta$\end{document} has no the independence property.
Creatinine/cystatin C ratio as a surrogate marker of residual muscle mass in amyotrophic lateral sclerosis
Authors: Tetsuka Syuichi , Morita Mitsuya , Ikeguchi Kunihiko , Nakano Imaharu
Published: February 2013

Aim

Identification of sensitive surrogate markers that indicate disease progression in amyotrophic lateral sclerosis might be useful in clinical trials and clinical care. Determination of the creatinine/cystatin C (Cr/CysC) ratio eliminates the effect of renal function on serum creatinine levels; therefore, we considered that the ratio might serve as a surrogate marker of residual muscle mass. We studied the Cr/CysC ratio as a useful surrogate marker of residual muscle mass in patients with amyotrophic lateral sclerosis.

Methods

A total of 103 participants were recruited: 62 patients with amyotrophic lateral sclerosis and 41 healthy controls. Serum levels of Cr and CysC were measured in both groups. We subsequently investigated the correlation between the Cr/CysC ratio and disease severity in patients with amyotrophic lateral sclerosis.

Results

The ratio was significantly lower in the amyotrophic lateral sclerosis group than in the control group. Furthermore, the ratio decreased as the severity of amyotrophic lateral sclerosis increased. The Cr/CysC ratio might be a better and more reliable method than the serum Cr level as a means of monitoring residual muscle mass of the entire body in patients with amyotrophic lateral sclerosis.

Conclusion

The present results show that the Cr/CysC ratio might be a suitable candidate for a useful and quantitative surrogate marker for the assessment of disease severity and progression in patients with amyotrophic lateral sclerosis.
What is the key player in TDP‐43 pathology in ALS: Disappearance from the nucleus or inclusion formation in the cytoplasm?
Authors: Onodera Osamu , Sugai Akihiro , Konno Takuya , Tada Mari , Koyama Akihide , Nishizawa Masatoyo
Published: February 2013

C9ORF72 and the 43 kDa TAR DNA‐binding protein (TDP‐43) are key molecules in the development of TDP‐43 pathology in amyotrophic lateral sclerosis (ALS). The hexanucleotide repeat expansion in C9ORF72 also leads to frontotemporal lobar degeneration, whereas mutation of TARDBP mainly causes ALS, indicating that TDP‐43 plays a more fundamental role in the development of ALS. In tissues affected with ALS, TDP‐43 is dislocated from the nucleus, forms cytoplasmic inclusions, and is phosphorylated and truncated. Accumulating evidence suggests that the disappearance of TDP‐43 from the nucleus precedes inclusion formation, indicating that its disappearance from the nucleus is crucial in the development of TDP‐43 pathology. Alterations in the quality and quantity of TDP‐43 might result in the disappearance of TDP‐43 from the nucleus. Regarding quality, phosphorylation and truncation of TDP‐43 is not necessary for its disappearance from the nucleus or for inclusion formation. Although it has been speculated that studies of TDP‐43 harboring ALS‐associated mutations are useful for understanding the molecular pathogenesis of sporadic ALS, the functional and biochemical differences between mutated and wild‐type TDP‐43 remain unclear. Regarding quantity, an increased amount of TDP‐43 is an attractive hypothesis as it has been shown that increased amounts of TDP‐43 are toxic. Moreover, several reports have suggested that increased levels of TDP‐43 are found in sporadic ALS as well as in ALS with TDP‐43 mutations. However, these findings remain controversial. Increased understanding of the mechanisms responsible for regulating TDP‐43 will provide a basis for determining the molecular pathogenesis of ALS.
Accelerating cyclic plasticity simulations using an adaptive wavelet transformation based multitime scaling method
Authors: Chakraborty Pritam , Ghosh Somnath
Published: February 2013

Cyclic finite element simulations of complex materials, for example, polycrystalline metals, are widely used to study fatigue failure due to plasticity and damage. Typically, this requires the simulation of a large number of cycles to failure for accurate determination of evolving deformation variables. Modeling cyclic deformation using conventional methods of time integration in semidiscretization techniques can however be computationally challenging. Single time scale integration methods typically follow the high frequency characteristics and discretize each cycle into a number of time steps over which integration is performed. To overcome this computational challenge, the wavelet transformation‐based multitime scale (WATMUS) method proposed in an earlier work by the authors is advanced and validated in this paper to perform accelerated finite element simulations of materials undergoing rate‐dependent plasticity for large number of cycles. Specifically, the WATMUS algorithm is integrated with crystal plasticity finite element method to perform accelerated simulations of polycrystalline alloys. The WATMUS methodology is also endowed with adaptive capabilities to optimally construct the wavelet basis functions and determine coarse‐scale cycle steps. Accuracy and efficiency of the WATMUS methodology is conclusively demonstrated by comparing the results with cyclic single‐time scale crystal plasticity finite element simulations performed on image‐based microstructure of titanium alloys. Copyright © 2012 John Wiley & Sons, Ltd.
Transient Fokker–Planck–Kolmogorov equation solved with smoothed particle hydrodynamics method
Authors: Canor T. , Denoël V.
Published: February 2013

Probabilistic theories aim at describing the properties of systems subjected to random excitations by means of statistical characteristics such as the probability density function ψ (pdf). The time evolution of the pdf of the response of a randomly excited deterministic system is commonly described with the transient Fokker–Planck–Kolmogorov (FPK) equation. The FPK equation is a conservation equation of a hypothetical or abstract fluid, which models the transport of probability. This paper presents a generalized formalism for the resolution of the transient FPK equation by using the well‐known mesh‐free Lagrangian method, smoothed particle hydrodynamics).

Numerical implementation shows notable advantages of this method in an unbounded state space: (1) the conservation of total probability in the state space is explicitly written; (2) no artifact is required to manage far‐field boundary conditions; (3) the positivity of the pdf is ensured; and (4) the extension to higher dimensions is straightforward.

Furthermore, thanks to the moving particles, this method is adapted for a large kind of initial conditions, even slightly dispersed distributions. The FPK equation is solved without any a priori knowledge of the stationary distribution, just a precise representation of the initial distribution is required.Copyright © 2013 John Wiley & Sons, Ltd.
POD–ISAT: An efficient POD‐based surrogate approach with adaptive tabulation and fidelity regions for parametrized steady‐state PDE discrete solutions
Authors: Bui D. , Hamdaoui M. , De Vuyst F.
Published: February 2013

A combination of proper orthogonal decomposition (POD) analysis and in situ adaptive tabulation (ISAT) is proposed for the representation of parameter‐dependent solutions of coupled partial differential equation problems. POD is used for the low‐order representation of the spatial fields and ISAT for the local representation of the solution in the design parameter space. The accuracy of the method is easily controlled by free threshold parameters that can be adjusted according to user needs. The method is tested on a coupled fluid‐thermal problem: the design of a simplified aircraft air control system. It is successfully compared with the standard POD; although the POD is inaccurate in certain areas of the design parameters space, the POD–ISAT method achieves accuracy thanks to trust regions based on residuals of the fluid‐thermal problem. The presented POD–ISAT approach provides flexibility, robustness and tunable accuracy to represent solutions of parametrized partial differential equations.Copyright © 2013 John Wiley & Sons, Ltd.
An implicit potential method for incompressible flows
Authors: Papadopoulos P.K.
Published: February 2013

In this paper, we consider a novel numerical scheme for solving incompressible flows on collocated grids. The implicit potential method utilizes an implicit potential velocity obtained from a Helmholtz decomposition for the mass conservation and employs a modified form of Bernoulli's law for the coupling of the velocity–pressure corrections. It requires the solution only of the momentum equations, does not involve the solution of additional partial differential equations for the pressure, and is applied on a collocated grid. The accuracy of the method is tested through comparison with analytical, experimental, and numerical data from the literature, and its efficiency and robustness are evaluated by solving several benchmark problems such as flow around a circular cylinder and in curved square and circular ducts.Copyright © 2013 John Wiley & Sons, Ltd.