bluuebunny/crossref_metadata_2025 huggingface dataset:
A hybrid finite‐element/finite‐difference method with an implicit–explicit time‐stepping scheme for Maxwell's equations
Authors: Zhu B. , Chen J. , Zhong W. , Liu Q. H.
Published: July 2012

This paper describes a hybrid technique in time domain that combines the explicit finite‐difference time‐domain (FDTD) method and the implicit finite‐element time‐domain (FETD) method based on the discontinuous Galerkin method to analyze transient electromagnetic problems. In the hybrid method, the FETD part uses the unconditionally stable Crank–Nicholson method with a triangular mesh, whereas the standard FDTD part employs a staggered Cartesian grid for spatial discretization and the leap‐frog scheme for time stepping. Nonconforming meshes are allowed between the structured FDTD grid and unstructured FETD meshes. The hybrid method takes advantages of the modeling flexibility of the FETD method for complex structures and the efficiency of the FDTD method for simple structures. The hybrid implicit–explicit time‐stepping scheme allows a time‐step increment as large as the stability limit for the FDTD method, which can be much larger than the stability criterion of the explicit FETD scheme with small elements. The hybrid scheme has second‐order accuracy. Numerical examples demonstrate the efficiency of the proposed method. Copyright © 2012 John Wiley & Sons, Ltd.
Synthetic organic pigments in contemporary Balinese painting: a Raman microscopy study
Authors: Marcelino Maria do Rosário , Muralha Vânia S. F.
Published: July 2012

The colour palette from two 20th century and one 21st century Indonesian paintings from the island of Bali was determined by Raman microscopy. There is very little information concerning the artistic techniques from this region of the world and the influences in materials introduced by western artists. The most interesting finding of our study was the increasing substitution of natural pigments by modern synthetic organic pigments. The findings were also compared with samples of representative pigments commonly used by Bali artists, donated by a renowned Balinese painter. Raman microscopy, combined with Fourier transform infrared spectroscopy, high‐performance liquid chromatography and μ‐EDXRF, was able to separate the different components on several colours, and to identify both synthetic organic pigments and inorganic components. Three azo pigments from the diarylide subclass, PY 83, PY 55 and PO 16, were identified on the yellow, brown, red and orange colours. A copper phthalocyanine blue PB 15:x and a basic dye BB 26 were responsible for the blue colours, the former admixed with ultramarine blue. Goethite was sometimes introduced to create the green colour. Two other basic dyes, BY2 and PG 4, were the main chromophores of the yellow and green samples of local pigments. The inorganic pigments comprised bone white, bone black, carbon‐based black pigment, haematite, goethite, vermilion, ultramarine blue and anatase. Finally, the ground layer of all the paintings was identified as rice starch, with a double function of a white pigment. Copyright © 2012 John Wiley & Sons, Ltd.
UV resonance Raman study of TrpZip2 and related peptides: π‐π interactions of tryptophan
Authors: Schlamadinger Diana E. , Leigh Brian S. , Kim Judy E.
Published: July 2012

Aromatic interactions are important stabilizing forces in proteins but are difficult to detect in the absence of high‐resolution structures. Ultraviolet resonance Raman spectroscopy is used to probe the vibrational signatures of aromatic interactions in TrpZip2, a synthetic β‐hairpin peptide that is stabilized by edge‐to‐face and face‐to‐face tryptophan π‐π interactions. The vibrational markers of isolated edge‐to‐face π‐π interactions are investigated in the related β‐hairpin peptide W2W11. The bands that comprise the Fermi doublet exhibit systematic shifts in position and intensity for TrpZip2 and W2W11 relative to the model peptide, W2W9, which does not form aromatic interactions. Additionally, hypochromism of the Bb absorption band of tryptophan in TrpZip2 leads to a decrease in the relative Raman cross‐sections of Bb‐coupled Raman bands. These results reveal spectral markers for stabilizing tryptophan π‐π interactions and indicate that ultraviolet resonance Raman may be an important tool for the characterization of these biological forces. Copyright © 2012 John Wiley & Sons, Ltd.
High performance Au/Ag core/shell bipyramids for determination of thiram based on surface‐enhanced Raman scattering
Authors: Zheng Xia , Chen Yanhua , Chen Yang , Bi Ning , Qi Haibo , Qin Meihong , Song Dan , Zhang Hanqi , Tian Yuan
Published: July 2012

Au/Ag core/shell bipyramids were used as surface‐enhanced Raman scattering (SERS) substrates to determine the thiram. The metallic substrates showed high SERS performance and are very suitable for the analytical sensors. The fabrication and characterization of the Au/Ag core/shell bipyramids were described. The influence of experimental parameters, such as the thickness of Ag shell of the bipyramids, sodium chloride concentration, and pH value on SERS of thiram was examined and optimized. Under the optimum conditions, thiram molecules were effectively adsorbed onto bipyramids and the SERS intensity is proportional to the concentration of thiram in the range of 3.3 to 400.0 ng mL–1. The corresponding correlation coefficient of the linear equation is 0.997, which indicates that there is a good linear relationship between SERS intensity and thiram concentration. The limit of detection for thiram is 2.0 ng mL–1. The experimental results indicate that the proposed method is a viable method for determination of thiram. Some environmental water samples were analyzed and the analytical results were satisfactory. Copyright © 2012 John Wiley & Sons, Ltd.
Assist devices: Machine preservation of extended criteria donors
Authors: Guarrera James V.
Published: July 2012

Key Points

1. Hypothermic machine perfusion (HMP) is in its infancy in clinical liver transplantation. Potential benefits include diminished preservation injury (PI) and improved graft function.

2. We have employed HMP in 21 extended criteria donor (ECD livers) at our center with excellent clinical outcomes.

3. Our experience with liver HMP is the only reported clinical experience worldwide representing a total of 41 successful liver transplant cases showing improved outcomes and diminished markers of ischemia/reperfusion injury.

4. Further multicenter and large scale trials are now warranted to further explore the benefits and applicability of liver HMP into the clinical mainstream. Liver Transpl, 2012. © 2012 AASLD.
Protein Conformational Studies for Macromolecularly Imprinted Polymers
Authors: Kryscio David R. , Fleming Michael Q. , Peppas Nicholas A.
Published: July 2012

CD is used to clearly show the negative impact of common ligands on the overall conformation of BSA, a typical protein template in macromolecularly imprinted polymers. This change occurs at concentrations far lower than those generally used in the literature. These findings are important as they offer insight into a potential fundamental reason for the lack of success in protein imprinting to date despite significant interest from the scientific community.

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Partial Hydrolysis of Poly(2‐ethyl‐2‐oxazoline) and Potential Implications for Biomedical Applications?
Authors: Van Kuringen Huub P. C. , Lenoir Joke , Adriaens Els , Bender Johan , De Geest Bruno G. , Hoogenboom Richard
Published: July 2012

The hydrolysis of PEtOx is studied to evaluate the potential toxicity of partially hydrolyzed polymers that might interfere with its increasing popularity for biomedical applications. The hydrolysis of PEtOx is studied in the presence of digestive enzymes (gastric and intestinal) and at 5.8 M hydrochloric acid as a function of temperature (57, 73, 90, and 100 °C). It is found that PEtOx undergoes negligible hydrolysis at 37 °C and that thermal and solution properties are not altered when up to 10% of the polymer backbone is hydrolyzed. Mucosal irritation and cytotoxicity is also absent up to 10% hydrolysis levels. In conclusion, PEtOx will not decompose at physiological conditions, and partial hydrolysis will not limit its biomedical applications.

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Enhanced Preparation of Alkoxyamine‐Functionalized Poly(p‐phenylene)s and Their Use as Macroinitiators for the Synthesis of Stimuli‐Responsive Coil‐Rod‐Coil Block Copolymers
Authors: Schmücker Simon , Kuckling Dirk
Published: July 2012

Herein, the enhanced preparation of alkoxyamine‐functionalized poly(p–phenylene)s (PPP) via Suzuki polycondensation (SPC) using microwave irradiation is described. Microwave heating effects a drastic decrease of reaction times compared to conventional heating. By varying the diboronic acid esters within the polymerization process different chain lengths of PPPs ($ \overline{M}_{\rm n}$ = 1900−3600 g mol−1) could be prepared. In addition, by exchange of the catalyst and base either preferably mono‐ or bis‐alkoxyamine‐terminated PPPs could be obtained. These macroinitiators are then applied for the nitroxide‐mediated radical polymerization (NMRP) of N–isopropylacrylamide (NIPAAm) to form PNIPAAm‐b‐PPP‐b‐PNIPAAm block copolymers ($ \overline{M}_{\rm n}$ = 24 900–38 400 g mol−1, $ \overline{M}_{\rm w}$/$ \overline{M}_{\rm n}$ = 1.54–1.67).
Does One Bad Apple(Juice) Spoil the Bunch? Implicit Attitudes Toward One Product Transfer to Other Products by the Same Brand
Authors: Ratliff Kate A. , Swinkels Bregje A. P. , Klerx Kimberly , Nosek Brian A.
Published: July 2012

If people like a product, they will automatically like another product from the same brand even if they do not know anything about it (demonstrated in Study 1). In one sense, this may be a reasonable inference—brands that have one good product may be likely to have other good products. But what if people learn that the second product is actually not good? Explicitly, people act as expected—the second product is disliked based on its negative features. Implicitly, however, people's positive attitude toward the first product still influences their liking of the second (Study 2). This attitude transfer effect (Ranganath & Nosek, 2008) shows that people are able to avoid using the qualities of one product to judge another explicitly. But, implicitly, once an attitude is formed toward a brand's product, other products by that brand will inherit some of the original evaluation regardless of their unique qualities.
Do Consumption Goals Matter? The Effects of Online Loyalty Programs in the Satisfaction‐Loyalty Relation
Authors: Suh Jung‐Chae , Yi Youjae
Published: July 2012

This study investigates the effects of online loyalty programs in the customer satisfaction‐loyalty relationship. It is proposed that loyalty programs may induce loyalty toward programs (program loyalty), which may then influence loyalty toward stores (store loyalty). According to the results of a two‐wave survey, consumption goals matter in the effects of program loyalty on online store loyalty. For consumers with hedonic goals, hedonic program loyalty (e.g., free gifts) has a significant effect on online loyalty. For consumers with utilitarian goals, however, utilitarian program loyalty (e.g., coupons) has a significant influence on online loyalty. Theoretical and managerial implications are also discussed.
Product Design: Preference for Rounded versus Angular Design Elements
Authors: Westerman Steve J. , Gardner Peter H. , Sutherland Ed J. , White Tom , Jordan Katie , Watts David , Wells Sophie
Published: July 2012

Two experiments tested whether a general relative preference for objects with rounded rather than angular form (Bar & Neta, 2006, 2007) can be applied in the context of the design of consumer products. Images of product packaging—a chocolate product (Experiment 1) and water and bleach bottles (Experiment 2)—were manipulated with regard to the shape of both contour and graphics. There was a preference for rounded designs that extended to self‐report purchase likelihood—with additive effects of contour and graphics shape that could not be accounted for by design typicality or perceived ease of use.
Novel Conjugated Polymers Based on Dithieno[3,2‐b:6,7‐b]carbazole for Solution Processed Thin‐Film Transistors
Authors: Chen Yagang , Liu Chengfang , Tian Hongkun , Bao Cheng , Zhang Xiaojie , Yan Donghang , Geng Yanhou , Wang Fosong
Published: July 2012

Two conjugated polymers (CPs) P‐tCzC12 and P‐tCzC16 comprising alternating dithieno[3,2‐b:6,7‐b]carbazole and 4,4′‐dihexadecyl‐2,2′‐bithiophene units have been designed and synthesized. Upon thermal annealing, they can form ordered thin films in which the polymer backbones dominantly adopted an edge‐on orientation respective to the substrate with a lamellar spacing of ≈24 Å and a π‐stacking distance of ≈3.7 Å. Organic thin‐film transistors (OTFTs) were fabricated by solution casting. A hole mobility of 0.39 cm2 V−1s−1 has been demonstrated with P‐tCzC16. This value is the highest among the CPs containing heteroacenes larger than 4 rings.
Controlling Thermochromism in a Photonic Block Copolymer Gel
Authors: Walish Joseph J. , Fan Yin , Centrone Andrea , Thomas Edwin L.
Published: July 2012

The tunable properties of stimulus‐responsive materials attract great interest in a variety of technological applications. Photonic gels are a new class of these materials, which can be tuned to reflect different wavelengths of light. Controlling this reflected color via temperature‐induced changes of self‐assembled photonic materials is important for their application in sensors and displays. In this work, the thermochromic behavior of a PS–P2VP photonic gel was found to originate from a temperature‐induced change in the pKa of the P2VP blocks. Control was obtained through the manipulation of the solution pH. The findings of this work provide the basis for understanding and controlling the properties of thermochromic block copolymers fostering their use in technologically relevant applications.
Semiflexibility Highlights the Polymers' Topology: Monte Carlo Studies
Authors: Berezovska Ganna , Dolgushev Maxim , Blumen Alexander
Published: July 2012

Summary: In this article we analyze in how far semiflexible behavior enhances the differences in the properties of classes of polymers whose topological structure varies. We focus on three pairs of macromolecular classes: stars vs. chains, unknotted rings vs. rings with one knot (trefoils), and stars vs. unknotted rings. For this we determine the mean‐square radii of gyration and the bond‐bond correlation functions through Monte Carlo simulations which use the bond fluctuation model. We show that introducing semiflexibility magnifies the differences between experimentally measurable quantities and may even lead to qualitative changes. Our simulation results are supported by theoretical studies which make use of the maximum entropy principle.
Synthesis and Solution Properties of Loose Polymer Brushes Having Polyimide Backbone and Methylmethacrylate Side Chains
Authors: Krasova Anna , Belyaeva Elena , Tarabukina Elena , Filippov Alexander , Meleshko Tamara , Ilgach Dmitry , Bogorad Natalia , Yakimansky Alexander
Published: July 2012

Summary: Graft‐copolymers with polyimide backbone and PMMA side chains are synthesized by ATRP of methylmethacrylate on the polyimide macroinitiator. The obtained copolymers, macroinitiator, and cleaved side chains are investigated by 1H NMR, SEC, static and dynamic light scattering, sedimentation, and viscosimetry in solutions. The synthesized copolymer is relatively loose polymer brushes: the average distance between grafted PMMA chains is ∼11 nm (4 repeat units of the backbone). The hydrodynamic and conformational characteristics of graft‐copolymers change on passage from ethylacetate to chloroform due to difference in the thermodynamic quality of the solvents with respect to the copolymer components. The backbone is characterized more extended conformation than individual polyimide macromolecule.
Thermostable Polycyanurate‐Polyhedral Oligomeric Silsesquioxane Hybrid Networks: Synthesis, Dynamics and Thermal Behavior
Authors: Starostenko Olga , Bershtein Vladimir , Fainleib Alexander , Egorova Larisa , Grigoryeva Olga , Sinani Alfred , Yakushev Pavel
Published: July 2012

Summary: A series of hybrid polycyanurate ‐ epoxy cyclohexyl‐functionalized polyhedral oligomeric silsesquioxane (PCN/ECH‐POSS) nanocomposite networks with ECH‐POSS content varying from 0.025 to 10 wt. % were synthesized and characterized using FTIR, DSC, DMA and CRS techniques. It was revealed that already as low as 0.025 wt. % POSS cardinally changed PCN glass transition characteristics including the strong shift of the transition onset to higher temperatures and manifesting a second, higher‐temperature glass transition characterizing interfacial dynamics; additionally, enhancing creep resistance and thermal stability at the earlier stage of degradation were observed.
Advances in the Prediction of Turn Structures in Peptides and Proteins
Authors: Koch Oliver
Published: July 2012

Turns are essential for protein structure as they allow the polypeptide chain to fold backup on itself. They also occur within protein binding sites, at proteinprotein interfaces and in small bioactive peptides, where they can play a crucial role for molecular recognition. Turn structures are an important class of protein secondary structure, although relatively little attention is paid to them with respect to helices and β‐sheets. Protein structure prediction, functional analysis of proteins and peptides, and computer‐aided drug design could all benefit from making use of accurately predicted turn structures from amino acid sequence. Here, recent advances of turn structure prediction and the underlying turn classification will be discussed together with their applications.
Efficacy of bioactive compounds from extra virgin olive oil to modulate atherosclerosis development
Authors: Lou‐Bonafonte José M. , Arnal Carmen , Navarro María A. , Osada Jesús
Published: July 2012

As olive oil is the main source of calories in the Mediterranean diet, a great deal of research has been devoted to characterizing its role in atherosclerosis. Virgin olive oil is an oily matrix that contains hydrocarbons, mainly squalene; triterpenes such as uvaol, erythrodiol, oleanolic, and maslinic acid; phytosterols; and a wide range of phenolic compounds comprising simple phenols, flavonoids, secoiridoids, and lignans. In this review, we analyze the studies dealing with atherosclerosis and olive oil in several species. A protective role of virgin olive oil against atherosclerosis has been shown in ApoE‐deficient mice and hamsters. In the former animal, sex, dose, and dietary cholesterol are modulators of the outcome. Contradictory findings have been reported for rabbits, a circumstance that could be due to the profusion of experimental designs, differing in terms of doses and animal strains, as well as sources of olive oils. This role has yet to be fully validated in humans. Minor components of olive oil have been shown to be involved in atherosclerosis protection. Nevertheless, evidence of the potential of isolated compounds or the right combination of them to achieve the antiatherosclerotic effect of virgin olive oil is inconclusive and will undoubtedly require further experimental support.
Polyphenol‐rich foods exhibit DNA antioxidative properties and protect the glutathione system in healthy subjects
Authors: Pedret Anna , Valls Rosa M. , Fernández‐Castillejo Sara , Catalán Úrsula , Romeu Marta , Giralt Montserrat , Lamuela‐Raventós Rosa M. , Medina‐Remón Alexander , Arija Victoria , Aranda Núria , Espinel Alberto , Delgado Marco Antonio , Solà Rosa
Published: July 2012

Scope

Polyphenols (ingested via food items) can decrease DNA, and oxidative damage of proteins and lipids. However, polyphenol effects in healthy populations have not been well defined. The aim of this study was to assess the relationship between urinary total polyphenol excretion (TPE), a biomarker of total polyphenol intake (TPI), polyphenol‐rich foods, and oxidative stress biomarkers in healthy adults of different ages participating in the cross‐sectional PAScual MEDicina study.

Methods and results

Urinary TPE was determined by Folin–Ciocalteau method in spot urine samples of 81 participants (46 women), classified into three age groups: 18 to 39, 40 to 54, and 55 to 72 years of age. TPI was quantified from 3‐day dietary records using the Phenol‐Explorer database. Urinary TPE increased with age (p < 0.001). Urinary TPE was inversely associated with urinary 8‐hydroxydeoxyguanosine (8‐OHdG; p<0.001) and erythrocyte‐oxidized glutathione concentrations (p < 0.05). A negative association between urinary 8‐OHdG and daily intake of polyphenols from vegetables and fermented beverages such as red wine was observed.

Conclusion

Urinary TPE increased with age and may reflect attenuation of oxidative damage. These results could explain the beneficial effects in healthy individuals of a diet rich in vegetables and moderate red wine; food items typical of the Mediterranean diet.
Trans fat involvement in cardiovascular disease
Authors: Ganguly Riya , Pierce Grant N.
Published: July 2012

Coronary heart disease is becoming a worldwide epidemic and diet and lifestyle are well known contributing factors. Identifying the kinds of foods that may have a cardioprotective or cardiotoxic effect and understanding their molecular mechanisms of action has become of increasing importance. Through largely epidemiological evidence, trans fatty acid (TFA) intake has been associated with a variety of cardiovascular complications including atherosclerosis. Traditionally, industrial TFAs (iTFAs) have been associated with these deleterious cardiovascular effects. However, there is a current body of research that suggests that ruminant trans fats (rTFAs) may have a cardioprotective role within the heart. The molecular mechanisms whereby TFAs are delivering their effects are largely unknown. In the following review, we discuss recent in vitro, animal and epidemiological research to better understand the effect of TFAs in the diet on cardiovascular disease, particularly atherosclerosis.
The role of marine omega‐3 (n‐3) fatty acids in inflammatory processes, atherosclerosis and plaque stability
Authors: Calder Philip C.
Published: July 2012

Atherosclerosis has an important inflammatory component and acute cardiovascular events can be initiated by inflammatory processes occurring in advanced plaques. Fatty acids influence inflammation through a variety of mechanisms; many of these are mediated by, or associated with, the fatty acid composition of cell membranes. Human inflammatory cells are typically rich in the n‐6 fatty acid arachidonic acid, but the contents of arachidonic acid and of the marine n‐3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can be altered through oral administration of EPA and DHA. Eicosanoids produced from arachidonic acid have roles in inflammation. EPA also gives rise to eicosanoids and these are usually biologically weak. EPA and DHA give rise to resolvins which are anti‐inflammatory and inflammation resolving. EPA and DHA also affect production of peptide mediators of inflammation (adhesion molecules, cytokines, etc.). Thus, the fatty acid composition of human inflammatory cells influences their function; the contents of arachidonic acid, EPA and DHA appear to be especially important. The anti‐inflammatory effects of marine n‐3 polyunsaturated fatty acids (PUFAs) may contribute to their protective actions towards atherosclerosis and plaque rupture.
Suboptimal dietary zinc intake promotes vascular inflammation and atherogenesis in a mouse model of atherosclerosis
Authors: Beattie John H. , Gordon Margaret‐Jane , Duthie Susan J. , McNeil Chris J. , Horgan Graham W. , Nixon Graeme F. , Feldmann Jörg , Kwun In‐Sook
Published: July 2012

Scope

Cardiovascular health is strongly influenced by diet. Zinc has antioxidant and anti‐inflammatory properties but its long‐term influence on vascular health at dietary intake levels relevant to the human population in developed countries has not been studied. We investigated the influence of suboptimal zinc intake in a Western‐type diet on the development of vascular inflammation and arterial plaque in apoE knock‐out (AEKO) mice.

Methods and results

Weanling AEKO and wild‐type (WT) controls were given high saturated fat (21% w/w) and high cholesterol (0.15%) semi‐synthetic diets containing 3 or 35 mg Zn/kg (AEKO and WT) or 8 mg Zn/kg (AEKO only) for over 6 months. AEKO mice on zinc intakes of 3 and 8 mg Zn/kg (suboptimal zinc) developed significantly (p < 0.05) more aortic plaque than AEKO mice consuming 35 mg Zn/kg (adequate zinc). Circulating levels of interleukin‐1β, interleukin‐6 and soluble vascular adhesion molecule‐1 were significantly (p < 0.05) raised at the lowest zinc intake in AEKO mice, as compared to zinc‐adequate controls. Plasma total cholesterol and total protein were also significantly (p < 0.05) increased at the lowest zinc intake.

Conclusion

We propose that suboptimal dietary zinc intake raises circulating pro‐atherogenic lipoprotein levels that promote vascular inflammation and enhance arterial plaque formation.
7Li+ NMR quadrupolar splitting in stretched hydrogels: developments in relaxation time estimation from z‐spectra
Authors: Puckeridge Max , Chapman Bogdan E. , Kuchel Philip W.
Published: July 2012

7Li NMR z‐spectra were recorded from the cation constituted in gelatin gels that were held stretched. The system has been studied previously, but we revisited the disparity that was noted between estimates of some of the relaxation times of spin‐states of various ranks and orders made using a global data‐fitting strategy and estimates made from data acquired by using multiple‐quantum‐filter pulse sequences. The global data fitting was performed with a probability approach along with the Markov chain Monte Carlo (MCMC) method applied to z‐spectra from 7Li+ dissolved in 1H2O using more refined experimental methods than hitherto. We also present a more extensive explanation of the MCMC method as it applies in the present NMR context. We achieved much closer agreement between the estimates of relaxation times made by using the two methods of analysis and attribute the previous discrepancies to spectral drift and z‐spectrum asymmetry. Copyright © 2012 John Wiley & Sons, Ltd.
Vanadium‐Modified Bimetallic Phillips Catalyst With High Branching Ability for Ethylene Polymerization
Authors: Matta Akanksha , Zeng Yanning , Taniike Toshiaki , Terano Minoru
Published: July 2012

In order to improve the branching ability of Phillips catalyst for ethylene polymerization, a new bimetallic Phillips catalyst was developed. In this work, a series of vanadium‐modified Phillips catalyst were prepared through co‐impregnation by varying the pH of the impregnation solution, the vanadium loading and the vanadium precursors. A method to prepare bimetallic Phillips catalyst having good catalytic performance was proposed. Catalyst characterization by diffuse reflectance UV‐Vis and X‐ray photoelectron spectroscopies clarified the key role of specific interaction between chromium and vanadium components for the improvements in branching ability and catalyst activity.

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Intrazelluläre Elektronenspinresonanz‐Spektroskopie
Authors: Drescher Malte
Published: July 2012

Methoden zur Aufklärung nativer Konformationen biologischer Makromoleküle in lebenden Zellen sind sehr gefragt — und rar. Jüngste methodische Entwicklungen erlauben jetzt intrazelluläre Abstandsmessungen mit Elektronenspinresonanz‐Spektroskopie.
Das Chemieinstitut auf der Alb
Authors: Lässing Volker
Published: July 2012

In diesem Jahr feiert das Max‐Planck‐Institut für Chemie in Mainz seinen hundertsten Geburtstag, denn am 23. Oktober 1912 öffnete es als Kaiser‐Wilhelm‐Institut für Chemie in Berlin‐Dahlem seine Türen. Neben Berlin und Mainz existierte das Institut aber noch sechs Jahre an einem dritten Standort: in der kleinen Stadt Tailfingen auf der Schwäbischen Alb.
Lactate detection in inducible and orthotopic Her2/neu mammary gland tumours in mouse models
Authors: Magnitsky S. , Belka G. K. , Sterner C. , Pickup S. , Chodosh L. A. , Glickson J. D.
Published: July 2012

This study compared the steady state concentration of lactate in an inducible Her2/nue transgenic breast cancer mouse model and in tumours from the same Her2/neu model grown orthotopically. In vivo lactate was detected by MRS using the Hadamard encoded selective multiple quantum coherence pulse sequence (HadSelMQC) recently developed by our laboratory. A lower lactate signal was observed in the inducible tumours compared to orthotopic tumours in vivo, while ex vivo analysis of perchloric acid extracts revealed similar amounts of this metabolite in both models. Histological staining of mammary tumour specimens showed a much higher level of fat tissue in inducible tumours compared to the orthotopic model. Phantom studies with [3‐13C] lactate indicated that a lipid environment could significantly reduce the T2 of lactate and impede its detection. The transgenic inducible model for breast cancer not only better recapitulated the biological aspects of the human disease but also provided additional characteristics related to in vivo detection of lactate that are not available in orthotopic or xenograft models. This study suggests that the level of lactate measured by the HadSelMQC pulse sequence may be underestimated in human patients in the presence of high lipid levels that are typically encountered in the breast. Copyright © 2012 John Wiley & Sons, Ltd.
Solution of the time‐harmonic viscoelastic inverse problem with interior data in two dimensions
Authors: Zhang Yixiao , Oberai Assad A , Barbone Paul E , Harari Isaac
Published: July 2012

We consider the problem of determining the distribution of the complex‐valued shear modulus for an incompressible linear viscoelastic material undergoing infinitesimal time‐harmonic deformation, given the knowledge of the displacement field in its interior. In particular, we focus on the two‐dimensional problems of anti‐plane shear and plane stress. These problems are motivated by applications in biomechanical imaging, where the material modulus distributions are used to detect and/or diagnose cancerous tumors. We analyze the well‐posedness of the strong form of these problems and conclude that for the solution to exist, the measured displacement field is required to satisfy rather restrictive compatibility conditions. We propose a weak, or a variational formulation, and prove the existence and uniqueness of solutions under milder conditions on measured data. This formulation is derived by weighting the original PDE for the shear modulus by the adjoint operator acting on the complex‐conjugate of the weighting functions. For this reason, we refer to it as the complex adjoint weighted equation (CAWE). We consider a straightforward finite element discretization of these equations with total variation regularization, and test its performance with synthetically generated and experimentally measured data. We find that the CAWE method is, in general, less diffusive than a corresponding least squares solution, and that the total variation regularization significantly improves its performance in the presence of noise. Copyright © 2012 John Wiley & Sons, Ltd.
An optimal versatile partial hybrid stress solid‐shell element for the analysis of multilayer composites
Authors: Rah K. , Van Paepegem W. , Degrieck J.
Published: July 2012

In the present contribution we propose an optimal low‐order versatile partial hybrid stress solid‐shell element that can be readily employed for a wide range of geometrically linear elastic structural analyses, that is, from shell‐like isotropic structures to multilayer anisotropic composites. This solid‐shell element has eight nodes with only displacement degrees of freedom and only a few internal parameters that provide the locking‐free behavior and accurate interlaminar shear stress resolution through the element thickness. These elements can be stacked on top of each other to model multilayer composite structures, fulfilling the interlaminar shear stress continuity at the interlayer surfaces and zero traction conditions on the top and bottom surfaces of composite laminates. The element formulation is based on the modified form of the well‐known Fraeijs de Veubeke–Hu–Washizu multifield variational principle with enhanced assumed strains formulation and assumed natural strains formulation to alleviate the different types of locking phenomena in solid‐shell elements. The distinct feature of the present formulation is its ability to accurately calculate the interlaminar shear stress field in multilayer structures, which is achieved by the introduction of the assumed interlaminar shear stress field in a standard enhanced assumed strains formulation based on the Fraeijs de Veubeke–Hu–Washizu principle. The numerical testing of the present formulation, employing a variety of popular numerical benchmark examples related to element patch test, convergence, mesh distortion, shell and laminated composite analyses, proves its accuracy for a wide range of structural analyses.Copyright © 2012 John Wiley & Sons, Ltd.
Strain control in nucleophilic cyclizations: reversal of exo‐selectivity in cyclizations of hydrazides of acetylenyl carboxylic acids by annealing to a pyrazole scaffold
Authors: Vasilevsky Sergei F. , Gold Brian , Mikhailovskaya Tatyana F. , Alabugin Igor V.
Published: July 2012

Independent of the nature of alkyne substitution, hydrazides of 4‐arylethynyl‐5‐carboxylic acid annealed at the pyrazole scaffold undergo a regioselective base‐catalyzed 6‐endo‐dig cyclization with the formation of pyrazolo[3,4‐c]pyridine‐7‐ones. This behavior contrasts the observation of selective 5‐exo closures in the analogous benzannelated systems and illustrates selective destabilization of the reaction path leading to the formation of a smaller ring. Computational analysis also reveals an important role of prototropic equilibria in rendering the overall cyclization feasible in the strained heterocyclic systems. The switch to the formation of a larger cycle suggests that strategic incorporation of strain can be used as a tool for the efficient control of regiochemistry of nucleophilic cyclizations. Copyright © 2012 John Wiley & Sons, Ltd.
Surface Dynamics of SiO2‐like Films on Polymers Grown by DBD Assisted CVD at Atmospheric Pressure
Authors: Premkumar Peter Antony , Starostin Sergey A. , de Vries Hindrik , Creatore Mariadriana , Koenraad Paul M. , MacDonald William A. , van de Sanden Mauritius C. M.
Published: July 2012

The development of the morphology and surface roughness of amorphous SiO2‐like films, on various polymeric substrates was analyzed by atomic force microscopy. The inorganic oxide films were deposited from organo‐silicon precursors with different reactive gases using dielectric barrier discharge assisted chemical vapor deposition (DBD‐CVD) at atmospheric pressure in a roll‐to‐roll configuration. Detailed study on the roughness statistical parameters characterizing morphology shows that DBD‐CVD films grow in a conformal and layer‐by‐layer like fashion on polymers very similar to films produced by atomic layer deposition process. Independent of substrate (planarised and non‐planarised polyethylene‐2,6‐napthalate) and methodology used to build the thickness as stacks or single layers, the films were found to be smooth, both locally and globally, and show negligible development of roughness with thickness (≤350 nm). The scaling exponents observed, show that the film growth does not fall into any of the universality classes that have been reported so far.

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Plasma Polymerization of Acrylic Acid by Atmospheric Pressure Nitrogen Plasma Jet for Biomedical Applications
Authors: Carton Olivier , Ben Salem Dhia , Bhatt Sudhir , Pulpytel Jérôme , Arefi‐Khonsari Farzaneh
Published: July 2012

Polyacrylic acid thin films have been deposited by an original and fast technique to grow organic coatings: a pulsed‐arc atmospheric pressure plasma jet. Liquid acrylic acid was introduced in the nitrogen plasma jet and OES was used to measure the fragmentation of the precursor. The films were characterized by XPS, FTIR and SEM analyses before and after soaking in water. The water stability was also investigated by weight loss measurement. A high retention of carboxylic moieties, i.e. functional groups of the monomer has been observed for coatings deposited under mild conditions for the jet (low frequency and high jet speed). These films have been used for cell adhesion using human ovarian carcinoma cells (NIH:OVCAR‐3). Good results have been obtained depending on the plasma parameters, showing that atmospheric pressure plasma jet is a promising technique to grow organic thin films for biomedical applications.

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Analysis of the Pressure Gradients According to Capsule Flow Mechanism
Authors: Ulusarslan Deniz
Published: July 2012

This study investigated the experimental coefficient in the mathematical correlation for the pressure gradient of spherical capsule train flow according to flow regimes. The investigation was carried out in the 1.2 × 104 < Re < 1.5 × 105 range and under transport concentration of 5 – 30 %. Deviation between the pressure drops measured by experiment and the mathematical correlation was calculated based on new experimental coefficients. The total pressure gradient in the two‐phase flow of the mixture was distinguished as pressure gradients caused by homogeneous flow and those caused by pressure drops, depending on the rotational movement of the capsules. The experimental findings indicate that at lower concentrations, the losses caused by the rotational movement are low, but the losses caused by the homogeneous flow are high. Losses caused by the rotational movement increase as the concentration increases.
A 4 year prospective study to determine risk factors for severe community acquired pneumonia in children in southern China
Authors: Zhang Qingli , Guo Zhongqin , Bai Zhenjiang , MacDonald Noni E.
Published: July 2012

Background

Pneumonia is the major cause of death under 5 years. With high CAP numbers in China and growing access to PICUs, factors associated with severe CAP need to be determined to optimize care.

Objective

To prospectively determine PICU CAP admission features and outcomes.

Methods

A 4 year prospective study of CAP aged 1 month to <14 years admitted to PICU, Children's Hospital Affiliated to Soochow University, China. All were managed in a standard manner. Clinical, laboratory, and imaging findings were collected systematically. All received antibiotics.

Results

Eight hundred ten (7%) of 10,836 CAP hospital admissions needed PICU. Seven hundred seven (87%) were enrolled. PICU CAP children were young (76% ≤ 12 months) and 33% had co‐morbid conditions; 21% congenital heart disease.21% required mechanical ventilation. The average length of PICU stay was 5 days (range, 3–27). The case fatality rate was 5.8%. Viruses were detected in 38%, RSV 24%; bacteria in 23%, Streptococcus pneumoniae 7%, Haemophilus influenza b 4%, Mycoplasma 11%. On single factor analysis, PICU admission respiratory rate >70/min, grunting/groaning, head nodding, cyanosis, and anemia were associated with respiratory failure and with fatality. On multivariate analysis only presence of congenital heart disease, Trisomy 21 and immunodeficiency correlated with fatality; not microbe nor PICU findings.

Conclusions

Young age and underlying congenital heart disease were associated factors for PICU support in CAP in China. Early referral if altered sensorium, high respiratory rate, head nodding, grunting and anemia, and universal access to conjugated vaccines may decrease morbidity and mortality. Pediatr Pulmonol. 2013; 48:390–397. © 2012 Wiley Periodicals, Inc.
Systemic effects of thiamethoxam and chlorantraniliprole seed treatments on adult Lissorhoptrus oryzophilus (Coleoptera: Curculionidae) in rice
Authors: Lanka Srinivas K , Ottea James A , Davis Jeffrey A , Hernandez Amy B , Stout Michael J
Published: July 2012

BACKGROUND: Feeding assays using adult rice water weevils and foliage of plants treated as seeds with chlorantraniliprole and thiamethoxam at different rates were conducted to evaluate the systemic adulticidal and feeding effects. Dose–mortality relationships were determined for thiamethoxam seed treatments by combining leaf area lost due to feeding and insecticide residues analyzed by LC/MS/MS. Changes in adulticidal activity of thiamethoxam were also investigated by contrasting adult mortalities at the 5–6‐leaf and tillering stages of rice.

RESULTS: Adult weevil mortalities and leaf consumption rates on foliage were affected in thiamethoxam but not in chlorantraniliprole treatments when rice was at the 6–7‐leaf stage. The LD50 for weevils feeding on thiamethoxam‐treated rice at the 2–3‐leaf stage was 447 pg insecticide weevil−1 (95% CL: 25–830 pg weevil−1) but was lower (142 pg weevil−1; 95% CL: 102–180 pg weevil−1) in experiments with 3–4‐leaf‐stage plants. Mortalities on leaves from 5–6‐leaf‐stage plants were consistently higher than on leaves from tillering plants. Thiamethoxam residues measured by ELISA increased with seed treatment rate and differed between plant stages.

CONCLUSION: The LD50 values developed in this study are the first values for leaf‐feeding insects on foliage of plants treated as seeds with thiamethoxam. The attrition of adulticidal activity of thiamethoxam in foliage of older plants may help to explain the reduced effectiveness of seed treatments against rice water larvae that is seen at later stages of rice growth in field studies. The differential activity of these two seed treatments on adults suggests that adult mortality contributes to the field efficacy of thiamethoxam but not to that of chlorantraniliprole. Copyright © 2012 Society of Chemical Industry
High‐level of resistance to spinosad, emamectin benzoate and carbosulfan in populations of Thrips tabaci collected in Israel
Authors: Lebedev Galina , Abo‐Moch Fauzi , Gafni Guy , Ben‐Yakir David , Ghanim Murad
Published: July 2012

BACKGROUND: The onion thrips, Thrips tabaci Lindeman, is a major pest of several crop plants in the genus Allium, such as onions, garlic and chives. In Israel, these crops are grown in open fields and in protected housing. This thrips is usually controlled by the application of chemical insecticides. In recent years, spinosad, emamectin benzoate and carbosulfan have been the major insecticides used for the control of the onion thrips. In the last 4 years, growers of chives and green onion from several regions of Israel have reported a significant decrease in the efficacy of insecticides used to control the onion thrips.

RESULTS: The susceptibility of 14 populations of the onion thrips, collected mainly from chives between the years 2007 and 2011, to spinosad, emamectin benzoate and carbosulfan was tested using a laboratory bioassay. The majority of the populations showed significant levels of resistance to at least one of the insecticides. LC50 values calculated for two of the studied populations showed that the resistance factor for spinosad compared with the susceptible population is 21 393, for carbosulfan 54 and for emamectin benzoate 36. Only two populations, collected from organic farms, were susceptible to the insecticides tested.

CONCLUSION: This is the first report of a high resistance level to spinosad, the major insecticide used to control the onion thrips. Resistance cases to spinosad were associated with failures to control the pest. Populations resistant to spinosad also had partial or complete resistance to other insecticides used for controlling the onion thrips. Copyright © 2012 Society of Chemical Industry
Laser characteristics of a heterostructure with a five Cd(Zn)Se QD sheet active region embedded in non‐symmetrical superlattice graded‐index waveguide
Authors: Lutsenko E. V. , Vainilovich A. G. , Tarasuk N. P. , Pavlovskii V. N. , Yablonskii G. P. , Alyamani A. , Sedova I. V. , Sorokin S. V. , Gronin S. V. , Kop'ev P. S. , Ivanov S. V.
Published: July 2012

Optically pumped green‐emitting (545–551 nm) ZnSe‐based laser heterostructures grown by molecular‐beam epitaxy have been elaborated and studied. The optimized II–VI laser heterostructure involves a non‐symmetrical Zn(Mg)SSe/ZnSe superlattice (SL) graded‐index waveguide and an active region comprising five CdSe quantum dot sheets each placed in the centre of a 2 nm‐thick ZnSe quantum well. Such a structure design provides both large optical confinement factor and high homogeneity of excitation. Internal laser parameters were determined by measuring the laser threshold and differential quantum efficiency as functions of the cavity length. The values of internal quantum efficiency, internal optical losses, characteristic gain and transparency threshold have been estimated to be ηi = 80.5%, αi = 3.2 cm–1, ΓG0 = 135 cm–1, and IT = 1.35 kW/cm2, respectively. Based on the defined parameters, the values of minimum threshold power and corresponding optimum cavity length have been derived. It is shown that the minimum threshold power decreases significantly (by more than 20%) in comparison with that for the heterostructure with conventional flat‐band SL waveguide (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Erratum: Strain relaxation mechanism of InGaN thin film grown on m‐GaN [Phys. Status Solidi C 8, 444–446 (2011)]
Authors: Hanada Takashi , Shimada Taka‐aki , Ji Shi‐Yang , Hobo Kenji , Liu Yuhuai , Matsuoka Takashi
Published: July 2012

The signs of the off‐angle toward +c‐direction of the miscut m‐GaN substrates indicated in Figs. 1 and 2 and in the text should be reversed. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Host structure dependence of light yield and proportionality in scintillators in terms of hot and thermalized carrier transport
Authors: Li Qi , Grim Joel Q. , Ucer K. B. , Burger A. , Bizarri G. A. , Moses W. W. , Williams R. T.
Published: July 2012

Several outstanding questions, including why complex halide scintillator host structures allow higher light yield and flatter electron energy response than simple monovalent metal halides, have remained unanswered by current models of luminescence in dense ionization tracks. Our measurements of nonlinear quenching kinetic order, recent literature on hot‐electron transport in scintillators, and calculations presented here of hot‐electron velocity from band structure of SrI2 and NaI, lead us to expand our previously described diffusion and nonlinear quenching model to include hot‐electron transport. Trends in multivalent versus monovalent metal halides, heavier versus lighter halides, and halides versus oxides versus semiconductors can be predicted based on optical phonon frequency, thermalized band edge mobilities, velocity in the upper conduction bands, and hole self‐trapping. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)