bluuebunny/crossref_metadata_2025 huggingface dataset:
Discrete concepts versus error analysis in PDE‐constrained optimization
Authors: Hinze Michael , Tröltzsch Fredi
Published: October 2010

Solutions to optimization problems with pde constraints inherit special properties; the associated state solves the pde which in the optimization problem takes the role of a equality constraint, and this state together with the associated control solves an optimization problem, i.e. together with multipliers satisfies first and second order necessary optimality conditions. In this note we review the state of the art in designing discrete concepts for optimization problems with pde constraints with emphasis on structure conservation of solutions on the discrete level, and on error analysis for the discrete variables involved. As model problem for the state we consider an elliptic pde which is well understood from the analytical point of view. This allows to focus on structural aspects in discretization. We discuss the approaches First discretize, then optimize and First optimize, then discretize, and consider in detail two variants of the First discretize, then optimize approach, namely variational discretization, a discrete concept which avoids explicit discretization of the controls, and piecewise constant control approximations. We consider general constraints on the control, and also consider pointwise bounds on the state. We outline the basic ideas for providing optimal error analysis and complement our analytical findings with numerical examples which confirm our analytical results (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Algorithms for PDE‐constrained optimization
Authors: Herzog Roland , Kunisch Karl
Published: October 2010

Some first and second order algorithmic approaches for the solution of PDE‐constrained optimization problems are reviewed. An optimal control problem for the stationary Navier‐Stokes system with pointwise control constraints serves as an illustrative example. Some issues in treating inequality constraints for the state variable and alternative objective functions are also discussed (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adaptive finite element discretization in PDE‐based optimization
Authors: Rannacher Rolf , Vexler Boris
Published: October 2010

This article surveys recent developments in the adaptive numerical solution of optimal control problems governed by partial differential equations (PDE). By the Euler‐Lagrange formalism the optimization problem is reformulated as a saddle‐point problem (KKT system) that is discretized by a Galerkin finite element method (FEM). Following the Dual Weighted Residual (DWR) approach the accuracy of the approximation is controlled by residual‐based a posteriori error estimates. This opens the way toward systematic complexity reduction in the solution of PDE‐based optimal control problems occurring in science and engineering (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
POD‐Galerkin approximations in PDE‐constrained optimization
Authors: Sachs Ekkehard W. , Volkwein Stefan
Published: October 2010

Proper orthogonal decomposition (POD) is one of the most popular model reduction techniques for nonlinear partial differential equations. It is based on a Galerkin‐type approximation, where the POD basis functions contain information from a solution of the dynamical system at pre‐specified time instances, so‐called snapshots. POD models have been applied very successfully in the area of optimization with PDEs or feedback control laws. Nevertheless, various issues are still unclear and are currently under research, e.g. timely updates of the snapshot information and error analyses for the POD approximations (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
MODELLING REFERENCE EVAPOTRANSPIRATION USING FEED FORWARD BACKPROPAGATION ALGORITHM IN ARID REGIONS OF AFRICA
Authors: Wang Yu‐Min , Traore Seydou , Kerh Tienfuan , Leu Jan‐Mou
Published: October 2010

Modelling of the evapotranspiration process is central for efficient management of agricultural water resources in arid regions. Reference evapotranspiration (ETo) computation with the recommended Penman–Monteith (PM) equation is limited in Burkina Faso due to the numerous meteorological data required. Recently, to solve the climatic data unavailability problem, an alternative reference model (RMBF) has been developed for Burkina Faso. In a new approach, this study explores in three production regions, Dori, Bogande and Fada N'Gourma, the potential of using the feed forward backpropagation (BP) neural network algorithm for estimating ETo from temperature data. Furthermore, four temperature‐based models including BP, RMBF, Hargreaves (HRG) and Blaney–Criddle (BCR) were employed and compared with the true PM. Based on the statistical evaluation, RMBF, HRG and BCR consistently overestimated the ETo and showed poor performance.Moreover, BP is superior to RMBF, HRG and BCR. Clearly, temperature‐based BP is more reliable than the other alternative methods for ETo modelling in Burkina Faso. It is found that both wind velocity and relative humidity improve BP accuracy when integrated into the network input. Relative humidity does not show as strong a correlation to ETo as wind. Wind was found as the key variable of ETo and is highly recommended to be in the BP model for these arid regions of Africa under study. Copyright © 2010 John Wiley & Sons, Ltd.
Comparison of pulsed photothermal radiometry, optical coherence tomography and ultrasound for melanoma thickness measurement in PDMS tissue phantoms
Authors: Wang Tianyi , Mallidi Srivalleesha , Qiu Jinze , Ma Li L. , Paranjape Amit S. , Sun Jingjing , Kuranov Roman V. , Johnston Keith P. , Milner Thomas E.
Published: October 2010

Melanoma accounts for 75% of all skin cancer deaths. Pulsed photothermal radiometry (PPTR), optical coherence tomography (OCT) and ultrasound (US) are non‐invasive imaging techniques that may be used to measure melanoma thickness, thus, determining surgical margins. We constructed a series of PDMS tissue phantoms simulating melanomas of different thicknesses. PPTR, OCT and US measurements were recorded from PDMS tissue phantoms and results were compared in terms of axial imaging range, axial resolution and imaging time. A Monte Carlo simulation and three‐dimensional heat transfer model was constructed to simulate PPTR measurement. Experimental results show that PPTR and US can provide a wide axial imaging range (75 μm–1.7 mm and 120–910 μm respectively) but poor axial resolution (75 and 120 μm respectively) in PDMS tissue phantoms, while OCT has the most superficial axial imaging range (14–450 μm) but highest axial resolution (14 μm). The Monte Carlo simulation and three‐dimensional heat transfer model give good agreement with PPTR measurement. PPTR and US are suited to measure thicker melanoma lesions (<$>><$>400 μm), while OCT is better to measure thin melanoma lesions (<$><<$>400 μm). (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Methane biodegradation in a two‐phase partition internal loop airlift reactor with gas recirculation
Authors: Rocha‐Rios José , Quijano Guillermo , Thalasso Frédéric , Revah Sergio , Muñoz Raul
Published: October 2010

BACKGROUND: The potential of organic liquid solvents and solid polymers to enhance CH4 mass transfer was studied in a two‐phase partition internal loop airlift reactor operated with gas recirculation under biotic and abiotic conditions. A preliminary screening of the most common liquid solvents (silicone oil 20 cSt, silicone oil 200 cSt and 2,2,4,4,6,8,8‐heptametilnonane) and solid polymers (Kraton® G6157, Desmopan® DP9370A and Elvax® 880) resulted in the selection of silicone oil 200 cSt (S200) and Desmopan DP9370A (D9370) for further investigation based on their high affinity for CH4, biocompatibility and nonbiodegradability.

RESULTS: Under abiotic conditions, the increase in gas recirculation from 0 to 1 vvm in the absence of a transfer vector increased the overall mass transfer coefficient for oxygen (kLa) by 195%. The presence of S200 and D9370 at 10% (v/v) under operation at 1 vvm of gas recirculation rate mediated an increase in kLa of 100% and 136%, respectively. Likewise, the increase in gas recirculation from 0 to 1 vvm in the absence of a transfer vector and in the presence of S200 during the continuous biodegradation of methane at 3% (v/v) and 7.3 min empty bed residence time resulted in increases in CH4 removal and CO2 production rates of 47% and 36%, respectively. Nevertheless, no significant enhancement in CH4 removal due to the presence of 10% of Desmopan or silicone oil was recorded under operation at 1 vvm.

CONCLUSIONS: These results suggest that microbial activity rather than mass transport could be the limiting step in biological CH4 abatement in this system, contrary to that observed in previous studies with stirred tank reactors, where the organic phase addition increased methane biodegradation. Copyright © 2010 Society of Chemical Industry
Gas‐diffusion microextraction
Authors: Pacheco João Grosso , Valente Inês Maria , Gonçalves Luís Moreira , Rodrigues José António , Barros Aquiles Araújo
Published: October 2010

Gas‐diffusion microextraction (GDME) is an innovative technique that combines the advantages of membrane‐aided gas‐diffusion with microextraction concepts. GDME makes uses of a novel portable and low‐cost device that comprises a small, commercially available, semi‐permeable membrane. Furthermore, if derivatization is integrated into the GDME concept, considerable enrichment factors can be obtained. It may become a powerful tool for any analyst who intends to quantify volatile and semi‐volatile analytes in various kinds of matrices. The analysis of vicinal diketones in beer was used as a case study to show GDME applicability and capabilities. Vicinal diketones were derivatized with o‐phenylenediamine and then determined by HPLC‐UV. Obtained results showed good repeatability and precision with extraction periods at the minute time span.
Long‐term cropping systems and tillage management effects on soil organic carbon stock and steady state level of C sequestration rates in a semiarid environment
Authors: Barbera V. , Poma I. , Gristina L. , Novara A. , Egli M.
Published: October 2010

A calcareous and clayey xeric Chromic Haploxerept of a long‐term experimental site in Sicily (Italy) was sampled (0–15 cm depth) under different land use management and cropping systems (CSs) to study their effect on soil aggregate stability and organic carbon (SOC). The experimental site had three tillage managements (no till [NT], dual‐layer [DL] and conventional tillage [CT]) and two CSs (durum wheat monocropping [W] and durum wheat/faba bean rotation [WB]). The annually sequestered SOC with W was 2·75‐times higher than with WB. SOC concentrations were also higher. Both NT and CT management systems were the most effective in SOC sequestration whereas with DL system no C was sequestered. The differences in SOC concentrations between NT and CT were surprisingly small. Cumulative C input of all cropping and tillage systems and the annually sequestered SOC indicated that a steady state occurred at a sequestration rate of 7·4 Mg C ha−1 y−1. Independent of the CSs, most of the SOC was stored in the silt and clay fraction. This fraction had a high N content which is typical for organic matter interacting with minerals. Macroaggregates (>250 µm) and large microaggregates (75–250 µm) were influenced by the treatments whereas the finest fractions were not. DL reduced the SOC in macroaggregates while NT and CT gave rise to higher SOC contents. In Mediterranean areas with Vertisols, agricultural strategies aimed at increasing the SOC contents should probably consider enhancing the proportion of coarser soil fractions so that, in the short‐term, organic C can be accumulated. Copyright © 2010 John Wiley & Sons, Ltd.
Inhibitory Effect of Hydrophilic Polymer Brushes on Surface‐Induced Platelet Activation and Adhesion
Authors: Zou Yuquan , Lai Benjamin F.L. , Kizhakkedathu Jayachandran N. , Brooks Donald E.
Published: October 2010

Poly(N,N‐dimethylacrylamide) (PDMA) brushes are successfully grown from unplasticized poly(vinyl chloride) (uPVC) by well‐controlled surface‐initiated atom transfer radical polymerization (SI‐ATRP). Molecular weights of the grafted PDMA brushes vary from ≈ 35 000 to 2 170 000 Da, while the graft density ranges from 0.08 to 1.13 chains · nm−2. The polydispersity of the grafted PDMA brushes is controlled within 1.20 to 1.80. Platelet activation (expression of CD62) and adhesion studies reveal that the graft densities of the PDMA brushes play an important role in controlling interfacial properties. PDMA brushes with graft densities between 0.35 and 0.50 chains · nm−2 induce a significantly reduced platelet activation compared to unmodified uPVC. Moreover, the surface adhesion of platelets on uPVC is significantly reduced by the densely grafted PDMA brushes. PDMA brushes that have high molecular weights lead to a relatively lower platelet activation compared to low‐molecular‐weight brushes. However, the graft density of the brush is more important than molecular weight in controlling platelet interactions with PVC. PDMA brushes do not produce any significant platelet consumption in platelet rich plasma. Up to a seven‐fold decrease in the number of platelets adhered on high graft density brushes is observed compared to the bare PVC surface. Unlike the bare PVC, platelets do not form pseudopodes or change morphology on PDMA brush‐coated surfaces.

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Differences in Cytotoxicity of β‐Sheet Peptides Originated from Silk and Amyloid β
Authors: Numata Keiji , Kaplan David L.
Published: October 2010

The relationships between amino acid sequence, nano‐assemblies, and cytotoxicity to neuron cytotoxicity were investigated using β‐sheet‐forming peptides from Araneus ventricosus spider silk, and amyloid forming peptides Aβ(12–28) (β1), Aβ(28–42) (β2), and full‐length Aβ(1–42). Although silk derived peptides formed nano‐assemblies, nanofilaments, and nanofibrils with β‐sheet contents raging from 24 to 40%, they showed no significant cytotoxicity to neurons. In contrast, nano‐assemblies and nanofibrils formed from Aβ peptides with high β‐sheet content demonstrated cytotoxicity to the neurons. These differences in cell response between the silk β‐sheets and Aβ peptides indicate that the general propensity to form beta sheets and form nanostructures is not sufficient to predict cytotoxicity, while surface charges of the assemblies are significant factors that impact cytotoxicity.

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Effect of Central Metals in the Porphyrin Ring on Photocurrent Performance of Cellulose Langmuir‐Blodgett Films
Authors: Sakakibara Keita , Nakatsubo Fumiaki
Published: October 2010

Role‐sharing functionalized cellulose derivatives having Mg, Zn, Cu, and Pd porphyrins are used for photocurrent generation system fabricated by the LB technique, mimicking the array of natural photosynthetic light‐harvesting systems. These polymers exhibited different absorption and redox properties in solution depending on the central metal ions. On visible light illumination, the LB film generated anodic photocurrent in the order of Pd > free base > Zn > Cu > Mg. By inserting Pd ion, using myristoyl group, and adjusting the DS, the photocurrent quantum yield was 6.9 times as great as that of conventional porphyrin cellulose. These findings may provide opportunities for the design of a new class of organic solar cells, based on cellulose molecular characteristics.

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Synthesis and Photovoltaic Properties of Side‐Chain Liquid‐Crystal Click Polymers for Dye‐Sensitized Solar‐Cells Application
Authors: Park Jin Su , Kim Yeol Ho , Song Myungkwan , Kim Chul‐Hyun , Karim Md. Anwarul , Lee Jae Wook , Gal Yeong‐Soon , Kumar Pankaj , Kang Shin‐Woong , Jin Sung‐Ho
Published: October 2010

SCLCPs are synthesized using “click chemistry”. The resulting polymers, P1 and P2, have good solubilities and molecular‐weight distributions. Their $\overline {M} _{{\rm w}} $ and polydispersities are in the ranges of 26.7–8.4 × 103 g · mol−1 and 1.99–1.29, respectively. DSC and POM studies reveal that both polymers exhibit liquid‐crystalline behavior. P1 and P2 are found to display blue emission. DSSCs are fabricated using P1 and P2 as matrices for electrolytes. The maximum PCE of the P1‐ and P2‐based polymer electrolytes is 4.11% (at 1 sun). This synthesis route has again proven to be a useful synthetic methodology for fabricating SCLCPs that are promising materials for device applications.

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Elaboration of Ultra‐High Molecular Weight Polyethylene/Carbon Nanotubes Electrospun Composite Fibers
Authors: Rein Dmitry M. , Cohen Yachin , Lipp Jonathan , Zussman Eyal
Published: October 2010

Micron‐sized fibers of UHMWPE reinforced with CNT were fabricated by the electrospinning process. Conditions for a metastable mutual solution of UHMWPE and CNTs were found at elevated temperature. These solutions were used for electrospining using a device having controlled temperature and gaseous environment around the electrospun liquid jet. The fabricated micron‐sized fibers exhibited the reinforcing CNTs as self‐organized nano‐ropes embedded within them. A post‐spinning drawing process enhanced the mechanical properties of the composite fibers to the level of 6.6 GPa strength and elongation at break of 6%. The CNT nano‐ropes form spontaneously in the liquid jet during electrospinning, and provide the reinforcement framework which is amenable for post‐drawing of the fibers for subsequent utilization as composite nanofibers. The experimental results exhibit the highest strength value reported to date for electrospun fibers.

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Characteristics of peri‐implantation porcine concepti population and maternal milieu influence the transcriptome profile
Authors: Blomberg Le Ann , Schreier Lori , Li Robert W.
Published: October 2010

Asynchrony of trophectoderm elongation, gestational days 11–12, is evident in porcine concepti, and rapid progression through this phase has been associated with conceptus competency. The goal of the current study was to determine the extent of transcriptomic responses of concepti to developmental delay and their physiological implications. Gestational day 11 concepti with the same morphology, ovoid and 7–8 mm, were isolated and designated as control or developmentally delayed if collected from a homogenous ovoid conceptus population or heterogeneous conceptus population (ovoid to filamentous), respectively. Total RNA prepared from four distinct control and four distinct developmentally delayed concepti, was analyzed using an Agilent high‐density custom porcine microarray. Two hundred nine transcripts were found differentially expressed between normal and developmentally delayed concepti. Functional analysis of these genes indicated that a significant number of the genes regulate signal transduction/transcription, organismal development, metabolism, and cell adhesion and can be modulated by transforming growth factor β1 (TGFβ1). Ten genes were selected for real‐time PCR validation of differential expression based on a known role in steroid synthesis, endometrium receptivity, and modulation of trophoblast differentiation/growth or interaction with TGFβ1. As in the microarray, all except one, achaete–scute complex homolog 2, were preferentially up‐regulated in delayed concepti. Overall, findings suggested that despite similar morphology, the transcriptome of developmentally delayed concepti is distinct from control counterparts. Also highlighted were ways by which the conceptus' microenvironment might be affected and developmental factors that may be of interest to interrogate further to determine if, and how, they affect embryo competency/elongation. Mol. Reprod. Dev. 77:978–989, 2010. Published 2010 Wiley‐Liss, Inc.
A comparison between simulated and experimental basis sets for assessing short‐TE in vivo1H MRS data at 1.5 T
Authors: Wilson Martin , Davies Nigel P. , Sun Yu , Natarajan Kal , Arvanitis Theodoros N. , Kauppinen Risto A. , Peet Andrew C.
Published: October 2010

A number of algorithms designed to determine metabolite concentrations from in vivo 1H MRS require a collection of single metabolite spectra, known as a basis set, which can be obtained experimentally or by simulation. It has been assumed that basis sets can be used interchangeably, but no systematic study has investigated the effects of small variations in basis functions on the metabolite values obtained. The aim of this study was to compare the results of simulated with experimental basis sets when used to fit short‐TE 1H MRS data of variable quality at 1.5 T. Two hundred and twelve paediatric brain tumour spectra were included in the analysis, and each was analysed twice with LCModel™ using a simulated and experimental basis set. To determine the influence of data quality on quantification, each spectrum was assessed and 152 were classified as being of ‘good’ quality. Bland–Altman statistics were used to measure the agreement between the two basis sets for all available spectra and only ‘good’‐quality spectra. Monte‐Carlo simulations were performed to investigate the influence of minor shifts in metabolite frequencies on metabolite concentration estimates. All metabolites showed good agreement between the two basis sets, and the average metabolite limits of agreement were approximately ±3.84 mM for all available data and ±0.99 mM for good‐quality data. Errors obtained from the Monte‐Carlo analysis were found to be more accurate than the Cramer–Rao lower bounds (CRLB) for 12 of 15 metabolites when metabolite frequency shifting was considered. For the majority of purposes, a level of agreement of ±0.99 mM between simulated and experimental basis sets is sufficiently small for them to be used interchangeably. Multiple analyses using slightly modified basis sets may be useful in estimating fitting errors, which are not predicted by CRLBs. Copyright © 2010 John Wiley & Sons, Ltd.
MRI of renal oxygenation and function after normothermic ischemia–reperfusion injury
Authors: Oostendorp Marlies , de Vries Eva E. , Slenter Jos M. G. M. , Peutz‐Kootstra Carine J. , Snoeijs Maarten G. , Post Mark J. , van Heurn L. W. Ernest , Backes Walter H.
Published: October 2010

The in vivo assessment of renal damage after ischemia–reperfusion injury, such as in sepsis, hypovolemic shock or after transplantation, is a major challenge. This injury often results in temporary or permanent nonfunction. In order to improve the clinical outcome of the kidneys, novel therapies are currently being developed that limit renal ischemia–reperfusion injury. However, to fully address their therapeutic potential, noninvasive imaging methods are required which allow the in vivo visualization of different renal compartments and the evaluation of kidney function. In this study, MRI was applied to study kidney oxygenation and function in a murine model of renal ischemia–reperfusion injury at 7 T. During ischemia, there was a strongly decreased oxygenation, as measured using blood oxygen level‐dependent MRI, compared with the contralateral control, which persisted after reperfusion. Moreover, it was possible to visualize differences in oxygenation between the different functional regions of the injured kidney. Dynamic contrast‐enhanced MRI revealed a significantly reduced renal function, comprising perfusion and filtration, at 24 h after reperfusion. In conclusion, MRI is suitable for the noninvasive evaluation of renal oxygenation and function. Blood oxygen level‐dependent or dynamic contrast‐enhanced MRI may allow the early detection of renal pathology in patients with ischemia–reperfusion injury, such as in sepsis, hypovolemic shock or after transplantation, and consequently may lead to an earlier intervention or change of therapy to minimize kidney damage. Copyright © 2010 John Wiley & Sons, Ltd.
Quantitative T2* imaging of metastatic human breast cancer to brain in the nude rat at 3 T
Authors: Song Ho‐Taek , Jordan Elaine K. , Lewis Bobbi K. , Gold Eric , Liu Wei , Frank Joseph A.
Published: October 2010

This study uses quantitative T2* imaging to track ferumoxides–protamine sulfate (FEPro)‐labeled MDA‐MB‐231BR‐Luc (231BRL) human breast cancer cells that metastasize to the nude rat brain. Four cohorts of nude rats were injected intracardially with FEPro‐labeled, unlabeled or tumor necrosis factor‐related apoptosis‐inducing ligand(TRAIL)‐treated (to induce apoptosis) 231BRL cells, or saline, in order to develop metastatic breast cancer in the brain. The heads of the rats were imaged serially over 3–4 weeks using gradient multi‐echo and turbo spin‐echo pulse sequences at 3 T with a solenoid receive‐only 4‐cm‐diameter coil. Quantitative T2* maps of the whole brain were obtained by the application of single‐exponential fitting to the signal intensity of T2* images, and the distribution of T2* values in brain voxels was calculated. MRI findings were correlated with Prussian blue staining and immunohistochemical staining for iron in breast cancer and macrophages. Quantitative analysis of T2* from brain voxels demonstrated a significant shift to lower values following the intracardiac injection of FEPro‐labeled 231BRL cells, relative to animals receiving unlabeled cells, apoptotic cells or saline. Quartile analysis based on the T2* distribution obtained from brain voxels demonstrated significant differences (p < 0.0083) in the number of voxels with T2* values in the ranges 10–35 ms (Q1), 36–60 ms (Q2) and 61–86 ms (Q3) from 1 day to 3 weeks post‐infusion of labeled 231BRL cells, compared with baseline scans. There were no significant differences in the distribution of T2* obtained from serial MRI in rats receiving unlabeled or TRAIL‐treated cells or saline. Histologic analysis demonstrated isolated Prussian blue‐positive breast cancer cells scattered in the brains of rats receiving labeled cells, relative to animals receiving unlabeled or apoptotic cells. Quantitative T2* analysis of FEPro‐labeled metastasized cancer cells was possible even after the hypointense voxels were no longer visible on T2*‐weighted images. Published in 2010 by John Wiley & Sons, Ltd.
On the hydrodynamic analysis of conformation in mixed biopolymer systems
Authors: Harding Stephen E , Abdelhameed Ali S , Morris Gordon A
Published: October 2010

A brief review is given of some of the advances in hydrodynamic methodologies for studying the conformation and flexibility of biomacromolecules in mixed systems. We consider first of all the evaluation of conformation type and flexibility in polymer systems with a quasi‐continuous distribution of molecular weight, using polysaccharides and mucin glycoproteins as our main examples, and then conformation determination in discrete or paucidisperse systems such as aggregated antibody preparations. Copyright © 2010 Society of Chemical Industry
Biodegradable poly(L‐lactide) and polycaprolactone block copolymer networks
Authors: Ivirico Jorge Luis Escobar , Salmerón‐Sánchez Manuel , Gómez Ribelles José Luis , Pradas Manuel Monleón
Published: October 2010

New biodegradable block copolymer networks were synthesized from methacrylate‐terminated poly(L‐lactide) (mLA) and polycaprolactone (mCL) macromers. This allowed the realization of a series of materials in which the macromer ratio can be used to tailor the physical and mechanical properties of the materials. The synthesis of the macromers was characterized using Fourier transform infrared (FTIR) spectroscopy and 1H NMR spectroscopy. Poly(mCL) and poly(mLA) networks were prepared by photopolymerization of the macromers, and copolymers were also prepared from the two macromers in various proportions. The phase microstructure of the new systems and the network architecture were investigated using differential scanning calorimetry, FTIR spectroscopy, dynamic mechanical analysis and thermogravimetry studies. Copyright © 2010 Society of Chemical Industry
Characterization of different poly(2‐oxazoline) block copolymers by MALDI‐TOF MS/MS and ESI‐Q‐TOF MS/MS
Authors: Baumgaertel Anja , Altuntaş Esra , Kempe Kristian , Crecelius Anna , Schubert Ulrich S.
Published: October 2010

A complete library of poly(2‐oxazoline) block copolymers was synthesized via cationic ring opening polymerization for the characterization by two different soft ionization techniques, namely matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) and electrospray ionization quadrupole time‐of‐flight mass spectrometry (ESI‐Q‐TOF MS). In addition, a detailed characterization was performed by tandem MS to gain more structural information about the block copolymer composition and its fragmentation behavior. The fragmentation of the poly(2‐oxazoline) block copolymers revealed the desired polymer structure and possible side reactions, which could be explained by different mechanisms, like 1,4‐ethylene or hydrogen elimination and the McLafferty +1 rearrangement. Polymers with aryl side groups showed less fragmentation due to their higher stability compared to polymers with alkyl side groups. These insights represent a further step toward the construction of a library with fragments and their fragmentation pathways for synthetic polymers, following the successful examples in proteomics. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Synthesis of end‐functionalized poly(phenylacetylene)s with well‐characterized palladium catalysts
Authors: Shiotsuki Masashi , Nakagawa Atsushi , Castañon Jesus Rodriguez , Onishi Naoya , Kobayashi Tatsurou , Sanda Fumio , Masuda Toshio
Published: October 2010

End‐functionalized poly(phenylacetylene)s were synthesized by the polymerization of phenylacetylene (PA) using the well‐defined palladium catalysts represented as [(dppf)PdBr(R)] {dppf = 1,1′‐bis(diphenylphosphino)ferrocene}. The Pd catalysts having a series of R groups such as o‐tolyl, mesityl, C(Ph)CPh2, C6H4‐o‐CH2OH, C6H4‐p‐CN, and C6H4‐p‐NO2 in conjunction with silver triflate polymerized PA to give end‐functionalized poly(PA)s bearing the corresponding R groups in high yields. The results of IR and NMR spectroscopies and MALDI‐TOF mass analyses proved the introduction of these R groups at one end of each polymer chain. The poly(PA) bearing a hydroxy end group was applied as a macroinitiator to the synthesis of a block copolymer composed of poly(PA) and poly(β‐propiolactone) moieties. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Probing the active site of the sugar isomerase domain from E. coli arabinose‐5‐phosphate isomerase via X‐ray crystallography
Authors: Gourlay Louise J. , Sommaruga Silvia , Nardini Marco , Sperandeo Paola , Dehò Gianni , Polissi Alessandra , Bolognesi Martino
Published: October 2010

Lipopolysaccharide (LPS) biosynthesis represents an underexploited target pathway for novel antimicrobial development to combat the emergence of multidrug‐resistant bacteria. A key player in LPS synthesis is the enzyme D‐arabinose‐5‐phosphate isomerase (API), which catalyzes the reversible isomerization of D‐ribulose‐5‐phosphate to D‐arabinose‐5‐phosphate, a precursor of 3‐deoxy‐D‐manno‐octulosonate that is an essential residue of the LPS inner core. API is composed of two main domains: an N‐terminal sugar isomerase domain (SIS) and a pair of cystathionine‐β‐synthase domains of unknown function. As the three‐dimensional structure of an enzyme is a prerequisite for the rational development of novel inhibitors, we present here the crystal structure of the SIS domain of a catalytic mutant (K59A) of E. coli
D‐arabinose‐5‐phosphate isomerase at 2.6‐Å resolution. Our structural analyses and comparisons made with other SIS domains highlight several potentially important active site residues. In particular, the crystal structure allowed us to identify a previously unpredicted His residue (H88) located at the mouth of the active site cavity as a possible catalytic residue. On the basis of such structural data, subsequently supported by biochemical and mutational experiments, we confirm the catalytic role of H88, which appears to be a generally conserved residue among two‐domain isomerases.
Calculating pKa values in the cAMP‐dependent protein kinase: The effect of conformational change and ligand binding
Authors: Bjarnadottir Una , Nielsen Jens Erik
Published: October 2010

The conformational change observed upon ligand binding and phosphorylation for the cAMP‐dependent protein kinase (protein kinase A—PKA) is of high importance for the regulation of its activity. We calculate pKa values and net charges for 18 3D structures of PKA in various conformations and liganded states to examine the role of electrostatics in ligand binding and activation. We find that the conformational change of PKA takes place without any significant net proton uptake/release at all pH values, thus indicating that PKA has evolved to reduce any pH‐dependent barriers to the conformational motion. We furthermore find that the binding of ligands induces large changes in the net charge of PKA at most pH values, but significantly, we find that the net charge difference at physiological pH is close to zero, thus indicating that the active‐site pKa values have been preorganized for substrate binding. We are unable to unequivocally resolve the identity of the groups responsible for determining the pH‐activity profile of PKA but speculate that the titration of Lys 168 or the titration of ATP itself could be responsible for the loss of activity at high pH values. Finally, we examine the effect of point mutations on the pKa values of the PKA catalytic residues and find these to be relatively insensitive to both noncharge‐altering and charge‐altering mutations.
Search for ferromagnetism in manganese‐stabilized zirconia
Authors: Dimri M. Chandra , Kooskora H. , Pahapill J. , Joon E. , Heinmaa I. , Subbi J. , Stern R.
Published: October 2010

Magnetic properties of Mn‐stabilized cubic zirconia (ZrO2) powder samples were investigated to verify the recent theoretical predictions of ferromagnetism in transition‐metal‐doped ZrO2. It was found that 5% Mn‐doped cubic ZrO2 samples, when heat treated in argon and air environments, exhibit tiny hysteresis loops at room temperature (300 K). Antiferromagnetic interactions were observed to be enhanced for higher Mn doping. Even though we could not produce the room‐temperature long‐range ferromagnetism in our samples, we discuss the observed effects of annealing on structural and magnetic properties and their sensitivity to moisture.
Improved switching characteristics of perovskite oxide‐based resistance random access memory by high‐pressure oxygen annealing at low temperature
Authors: Lee Wootae , Jo Minseok , Park Jubong , Lee Joonmyoung , Park Sangsu , Kim Seonghyun , Jung Seungjae , Shin Jungho , Lee Daeseok , Siddik Manzar , Hwang Hyunsang
Published: October 2010

We successfully fabricated perovskite oxide‐based resistance random access memory (RRAM) with improved resistance switching characteristics, at a low temperature. A high‐pressure oxygen‐annealed (HPOA) W/Al/Pr0.7Ca0.3MnO3 (PCMO)/Pt device shows good memory characteristics such as device uniformity, endurance, and improved switching speed. X‐ray photoelectron spectroscopy reveals large amounts of oxygen effectively incorporated into the PCMO layer during HPOA, enhancing the crystallization of PCMO at low temperature. X‐ray diffraction analysis confirmed that an amorphous PCMO layer was converted to a polycrystalline structure. These results suggest that HPOA is a promising method for fabricating reliable perovskite oxide‐based RRAM at a low temperature.
Testing non‐inferiority and superiority for two endpoints for several treatments with a control
Authors: Lawrence John
Published: October 2010

Some multiple comparison procedures are described for multiple armed studies. The procedures are appropriate for testing all hypotheses for comparing two endpoints and multiple test arms to a single control group, for example three different fixed doses compared to a placebo. The procedure assumes that among the two endpoints, one is designated as a primary endpoint such that for a given treatment arm, no hypothesis for the secondary endpoint can be rejected unless the hypothesis for the primary endpoint was rejected. The procedures described control the family‐wise error rate in the strong sense at a specified level α. Copyright © 2010 John Wiley & Sons, Ltd.
Three‐dimensional image‐guided placement of percutaneous pedicle screws without the use of biplanar fluoroscopy or Kirschner wires: technical note
Authors: Nottmeier Eric W. , Fenton Douglas
Published: October 2010

Background

Percutaneous pedicle screws are commonly used in minimally invasive spinal procedures. Traditional techniques of percutaneous pedicle screw placement have employed the use of multiplanar fluoroscopy and Kirschner wires (K‐wires). The use of multiplanar fluoroscopy for the placement of percutaneous pedicle screws likely increases radiation exposure to the surgeon when compared to open techniques. K‐wires can break or become bent during the procedure, making it difficult to insert and remove instrumentation over them. Additionally, there is also a risk of visceral or vascular injury with the use of K‐wires. The authors present a novel method of percutaneous pedicle screw placement utilizing three‐dimensional (3D) fluoroscopy‐based image guidance in which K‐wires are not used and there is minimal to no radiation exposure to the surgeon and operating room staff.

Methods

Thirty‐six screws were placed in 15 patients using this technique. An independent radiologist graded screw placement using computed tomographic (CT) scans and the breach rate of the percutaneous pedicle screws was compared to the breach rate of 33 pedicle screws placed contralaterally using the mini‐open technique.

Results

No bony breach was noted by any screw in either group and no complications occurred in this study as a result of screw placement.

Conclusions

Percutaneous pedicle screws can be placed accurately and safely using 3D image guidance without the use of K‐wires. Little to no radiation exposure to the surgeon or OR staff occurs with this technique. No complications occurred in this study as a result of screw placement or image guidance. Copyright © 2010 John Wiley & Sons, Ltd.
Mechanisms of genetic variation in polioviruses
Authors: Savolainen‐Kopra Carita , Blomqvist Soile
Published: October 2010

Polioviruses, as with all RNA viruses, are in a constant process of evolution driven by different mechanisms. With multiple mechanisms for genetic variability, they are successful conformists, adapting to changes in their habitat. The evolution of polioviruses may occur with generation of point mutations followed by genetic drift and selection. The mutation rate of polioviruses based on several studies is approximately 3 × 10−2 mutations/synonymous site/year in the gene encoding viral protein 1. Genetic variation in polioviruses may also be increased by sharing of genetic data of two different poliovirus lineages by means of homologous recombination. According to the current view, recombination is considered usually to occur by strand‐switching, but a non‐replicative model has also been described. In recombination, polioviruses may either gain a set of advantageous mutations selected and fixed in previous generations of the parental viruses or get rid of deleterious ones. The prerequisites and constraints of the evolution mechanisms will be discussed. Furthermore, consequences of poliovirus evolution will be reviewed in the light of observations made on currently circulating polioviruses. We will also describe how polioviruses strike back: as wild type polioviruses approach eradication, vaccine derived strains increase their occurrence and genetic variability. Copyright © 2010 John Wiley & Sons, Ltd.
Mitochondrial DNA Integrity Is Essential For Mitochondrial Maturation During Differentiation of Neural Stem Cells
Authors: Wang Wei , Osenbroch Pia , Skinnes Ragnhild , Esbensen Ying , Bjørås Magnar , Eide Lars
Published: October 2010

Differentiation of neural stem cells (NSCs) involves the activation of aerobic metabolism, which is dependent on mitochondrial function. Here, we show that the differentiation of NSCs involves robust increases in mitochondrial mass, mitochondrial DNA (mtDNA) copy number, and respiration capacity. The increased respiration activity renders mtDNA vulnerable to oxidative damage, and NSCs defective for the mitochondrial 8-oxoguanine DNA glycosylase (OGG1) function accumulate mtDNA damage during the differentiation. The accumulated mtDNA damages in ogg1−/− cells inhibit the normal maturation of mitochondria that is manifested by reduced cellular levels of mitochondrial encoded complex proteins (complex I [cI], cIII, and cIV) with normal levels of the nuclear encoded cII present. The specific cI activity and inner membrane organization of respiratory complexes are similar in wt and ogg1−/− cells, inferring that mtDNA damage manifests itself as diminished mitochondrial biogenesis rather than the generation of dysfunctional mitochondria. Aerobic metabolism increases during differentiation in wild-type cells and to a lesser extent in ogg1−/− cells, whereas anaerobic rates of metabolism are constant and similar in both cell types. Our results demonstrate that mtDNA integrity is essential for effective mitochondrial maturation during NSC differentiation.
Knowledge of prenatal screening and psychological management of test decisions
Authors: Dahl K. , Hvidman L. , Jørgensen F. S. , Kesmodel U. S.
Published: October 2010

Objectives

To study associations between pregnant women's knowledge of prenatal screening and decisional conflict in deciding whether to participate in first‐trimester screening for Down syndrome in a setting of required informed consent, and to study associations between knowledge and personal wellbeing, and worries in pregnancy.

Methods

A population‐based cross‐sectional study with 6427 pregnant women consecutively included before the time of a nuchal translucency scan. Participants were recruited from three Danish obstetric departments offering prenatal screening free of charge. The results presented are based on 4111 pregnant women (64%). Knowledge was measured using 15 questions. The primary outcomes were measured using pre‐existing validated scales, i.e. The Decisional Conflict Scale, the WHO Well‐Being Index and the Cambridge Worry Scale. Associations were analyzed by multivariate logistic and linear regression analyses.

Results

A higher level of knowledge was associated with less decisional conflict when deciding whether to participate in first‐trimester Down syndrome screening (adjusted odds ratio 1.31 (95% CI, 1.26–1.37)). An increased level of knowledge was also associated with higher levels of wellbeing (adjusted linear coefficient 0.51 (95% CI, 0.26–0.75), P < 0.001). Knowledge was not associated with worries, either in general or specifically about something being wrong with the baby.

Conclusion

The results of this study indicate the importance of ensuring a high level of knowledge for pregnant women making choices about participation in prenatal screening for Down syndrome in order to improve the psychological management of test decisions. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Game theory
Authors: Dufwenberg Martin
Published: October 2010

Game theory is a toolkit for examining situations where decision makers influence each other. I discuss the nature of game‐theoretic analysis, the history of game theory, why game theory is useful for understanding human psychology, and why game theory has played a key role in the recent explosion of interest in the field of behavioral economics. WIREs Cogni Sci 2011 2 167–173 DOI: 10.1002/wcs.119

This article is categorized under:

Neuroscience > Cognition
The use of technology to enhance zoological parks
Authors: Clay Andrea W. , Perdue Bonnie M. , Gaalema Diann E. , Dolins Francine L. , Bloomsmith Mollie A.
Published: October 2010

Technology can be used in a zoological setting to improve visitor experience, increase research opportunities, and enhance animal welfare. Evaluating the quality of these technological innovations and their use by nonhuman and human counterparts is a critical part of extending the uses of technology to enhance animal welfare and visitor experience at zoological parks. Survey data from a small sample of institutions housing primates suggest that computers, television, radio, and sprinklers are the most prevalent types of technological enrichment currently used. Survey respondents were positive about the technology implemented, stating a desire to increase its use. Zoo Biol 30:487–497, 2011. © 2010 Wiley Periodicals, Inc.
The Subprime Crisis and African Americans—Response
Authors: Price Gregory N.
Published: October 2010

These remarks constitute a response to Sandra Philip's consideration of the subprime mortgage crisis and African Americans. While Philip's analysis of the recent collapse of the sub-prime mortgage market and its impact on African Americans is insightful and poignant, the scope of the analysis does not consider the role that race, inequality, political economy and stratification may have had. This response considers Philip's treatment of the subprime crisis within a broader political economy context whereby the legacy of race, inequality and stratification may have provided incentives for financial institutions to engage in racially predatory lending practices that increased the level of risk—which ultimately caused the collapse of the subprime mortgage market, and the attendant financial crisis.
Missed and/or Misinterpreted Lesions in Breast Ultrasound: Reasons and Solutions
Authors: Park Jeong Mi , Yang Limin , Laroia Archana , Franken Edmund A. , Fajardo Laurie L.
Published: October 2010

Understanding the many variables that affect the efficacy of breast US and the skills required for problem solving are important elements for successful performance of this technique.
Site‐specific cleavage of the 40S ribosomal subunit reveals eukaryote‐specific ribosomal protein S28 in the subunit head
Authors: Malygin Alexey A. , Karpova Galina G.
Published: October 2010

MINT‐8044065: S29 (uniprotkb:P62273), S28 (uniprotkb:P62857), S19 (uniprotkb:P39019), S14 (uniprotkb:P62263) and S16 (uniprotkb:P62249) colocalize (MI:0403) by cosedimentation through density gradient (MI:0029)
Prävention von Essstörungen – vom Pilotprojekt zur Routinemaßnahme
Authors: Berger Uwe , Wick Katharina , Schwartze Dominique , Strauß Bernhard
Published: October 2010

Einleitung

Das Gefühl der Ohnmacht gegenüber der Macht der Magersucht ruft Gesundheitsexperten auf den Plan, um dieser nach wie vor „rätselhaften Erkrankung“ Einhalt zu gebieten. In Thüringen wurde ein Programm zur Primärprävention von Magersucht bei Mädchen ab 12 Jahren (kurz: PriMa) entwickelt und nach den Standards der „Society for Prevention Research“ (SPR) in drei Schritten „Erprobung“, „Bewährung im Feld“ und „flächendeckende Verbreitung“ umfassend evaluiert.