bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plastic Dissipation Mechanisms in Periodic Microframe‐Structured Polymers
Authors: Wang Lifeng , Boyce Mary C. , Wen Cheng‐Yen , Thomas Edwin L. 
Published: March 2009

AbstractNovel lightweight micro‐ and nanostructured materials are being used as constituents in hierarchically structured composites for providing high stiffness, high strength, and energy absorbing capability at low weight. Three dimensional SU‐8 periodic microframe materials with submicrometer elements exhibit unusual large plastic deformations. Here, the plastic dissipation and mechanical response of polymeric microframe structures is investigated using micromechanical modeling of large deformations. Finite element analysis shows that multiple deformation domains initiate, stabilize, and then spread plasticity through the structure; simulated deformation mechanisms and deformation progression are found to be in excellent agreement with experimental observation. Furthermore, the geometry can be used to tailor aspects of 3D behavior such as effective lateral contraction ratios (elastic and plastic) during tensile loading as well as negative normal stress during simple shear deformation. The effects of structural geometry on mechanical response are also studied to tailor and optimize mechanical performance at a given density. These quantitative investigations enable simulation‐based design of optimal lightweight material microstructures for dissipating energy.
Triplet Harvesting in Hybrid White Organic Light‐Emitting Diodes
Authors: Schwartz Gregor , Reineke Sebastian , Rosenow Thomas Conrad , Walzer Karsten , Leo Karl 
Published: March 2009

AbstractWhite organic light‐emitting diodes (OLEDs) are highly efficient large‐area light sources that may play an important role in solving the global energy crisis, while also opening novel design possibilities in general lighting applications. Usually, highly efficient white OLEDs are designed by combining three phosphorescent emitters for the colors blue, green, and red. However, this procedure is not ideal as it is difficult to find sufficiently stable blue phosphorescent emitters. Here, a novel approach to meet the demanding power efficiency and device stability requirements is discussed: a triplet harvesting concept for hybrid white OLED, which combines a blue fluorophor with red and green phosphors and is capable of reaching an internal quantum efficiency of 100% if a suitable blue emitter with high‐lying triplet transition is used is introduced. Additionally, this concept paves the way towards an extremely simple white OLED design, using only a single emitter layer.
Glutathione peroxidase activity modulates recovery in the injured immature brain
Authors: Tsuru‐Aoyagi Kyoko , Potts Matthew B. , Trivedi Alpa , Pfankuch Timothy , Raber Jacob , Wendland Michael , Claus Catherine P. , Koh Seong‐Eun , Ferriero Donna , Noble‐Haeusslein Linda J. 
Published: March 2009

AbstractObjectiveMice subjected to traumatic brain injury at postnatal day 21 show emerging cognitive deficits that coincide with hippocampal neuronal loss. Here we consider glutathione peroxidase (GPx) activity as a determinant of recovery in the injured immature brain.MethodsWild‐type and transgenic (GPxTg) mice overexpressing GPx were subjected to traumatic brain injury or sham surgery at postnatal day 21. Animals were killed acutely (3 or 24 hours after injury) to assess oxidative stress and cell injury in the hippocampus or 4 months after injury after behavioral assessments.ResultsIn the acutely injured brains, a reduction in oxidative stress markers including nitrotyrosine was seen in the injured GPxTg group relative to wild‐type control mice. In contrast, cell injury, with marked vulnerability in the dentate gyrus, was apparent despite no differences between genotypes. Magnetic resonance imaging demonstrated an emerging cortical lesion during brain maturation that was also indistinguishable between injured genotypes. Stereological analyses of cortical volumes likewise confirmed no genotypic differences between injured groups. However, behavioral tests beginning 3 months after injury demonstrated improved spatial memory learning in the GPxTg group. Moreover, stereological analysis within hippocampal subregions demonstrated a significantly greater number of neurons within the dentate of the GPx group.InterpretationOur results implicate GPx in recovery of spatial memory after traumatic brain injury. This recovery may be attributed, in part, to a reduction in early oxidative stress and selective, long‐term sparing of neurons in the dentate. Ann Neurol 2009;65:540–549
Magnetic resonance imaging as a potential surrogate for relapses in multiple sclerosis: A meta‐analytic approach
Authors: Sormani Maria Pia , Bonzano Laura , Roccatagliata Luca , Cutter Gary R. , Mancardi Gian Luigi , Bruzzi Paolo 
Published: March 2009

AbstractObjectiveThe aim of this work was to evaluate whether the treatment effects on magnetic resonance imaging (MRI) markers at the trial level were able to predict the treatment effects on relapse rate in relapsing‐remitting multiple sclerosis.MethodsWe used a pooled analysis of all the published randomized, placebo‐controlled clinical trials in relapsing‐remitting multiple sclerosis reporting data both on MRI variables and relapses. We extracted data on relapses and on MRI “active” lesions. A regression analysis weighted on trial size and duration was performed to study the relation between the treatment effect on relapses and the treatment effect on MRI lesions. We validated the estimated relation on an independent set of clinical trials satisfying the same inclusion criteria but with a control arm other than placebo.ResultsA set of 23 randomized, double‐blind, placebo‐controlled trials in relapsing‐remitting multiple sclerosis was identified, for a total of 63 arms, 40 contrasts, and 6,591 patients. A strong correlation was found between the effect on the relapses and the effect on MRI activity. The adjusted R2 value of the weighted regression line was 0.81. The regression equation estimated using the placebo‐controlled trials gave a satisfactory prediction of the treatment effect on relapses when applied to the validation set.InterpretationMore than 80% of the variance in the effect on relapses between trials is explained by the variance in MRI effects. Smaller and shorter phase II studies based on MRI lesion end points may give indications also on the effect of the treatment on relapse end points. Ann Neurol 2009;65:268–275
Cerebrospinal fluid biomarker signature in Alzheimer's disease neuroimaging initiative subjects
Authors: Shaw Leslie M. , Vanderstichele Hugo , Knapik‐Czajka Malgorzata , Clark Christopher M. , Aisen Paul S. , Petersen Ronald C. , Blennow Kaj , Soares Holly , Simon Adam , Lewczuk Piotr , Dean Robert , Siemers Eric , Potter William , Lee Virginia M.‐Y. , Trojanowski John Q. ,   Alzheimer's Disease Neuroimaging Initiative
Published: March 2009

AbstractObjectiveDevelop a cerebrospinal fluid biomarker signature for mild Alzheimer's disease (AD) in Alzheimer's Disease Neuroimaging Initiative (ADNI) subjects.MethodsAmyloid‐β 1 to 42 peptide (Aβ1–42), total tau (t‐tau), and tau phosphorylated at the threonine 181 were measured in (1) cerebrospinal fluid (CSF) samples obtained during baseline evaluation of 100 mild AD, 196 mild cognitive impairment, and 114 elderly cognitively normal (NC) subjects in ADNI; and (2) independent 56 autopsy‐confirmed AD cases and 52 age‐matched elderly NCs using a multiplex immunoassay. Detection of an AD CSF profile for t‐tau and Aβ1–42 in ADNI subjects was achieved using receiver operating characteristic cut points and logistic regression models derived from the autopsy‐confirmed CSF data.ResultsCSF Aβ1–42 was the most sensitive biomarker for AD in the autopsy cohort of CSF samples: receiver operating characteristic area under the curve of 0.913 and sensitivity for AD detection of 96.4%. In the ADNI cohort, a logistic regression model for Aβ1–42, t‐tau, and APOε4 allele count provided the best assessment delineation of mild AD. An AD‐like baseline CSF profile for t‐tau/Aβ1–42 was detected in 33 of 37 ADNI mild cognitive impairment subjects who converted to probable AD during the first year of the study.InterpretationThe CSF biomarker signature of AD defined by Aβ1–42 and t‐tau in the autopsy‐confirmed AD cohort and confirmed in the cohort followed in ADNI for 12 months detects mild AD in a large, multisite, prospective clinical investigation, and this signature appears to predict conversion from mild cognitive impairment to AD. Ann Neurol 2009
Free sialic acid storage disease without sialuria
Authors: Mochel Fanny , Yang Bingzhi , Barritault Julie , Thompson Jerry N. , Engelke Udo F. H. , McNeill Nathan H. , Benko William S. , Kaneski Christine R. , Adams David R. , Tsokos Maria , Abu‐Asab Mones , Huizing Marjan , Seguin Francois , Wevers Ron A. , Ding Jiahuan , Verheijen Frans W. , Schiffmann Raphael 
Published: March 2009

AbstractWe performed high‐resolution in vitro proton nuclear magnetic resonance spectroscopy on cerebrospinal fluid and urine samples of 44 patients with leukodystrophies of unknown cause. Free sialic acid concentration was increased in cerebrospinal fluid of two siblings with mental retardation and mild hypomyelination. By contrast, urinary excretion of free sialic acid in urine was normal on repeated testing by two independent methods. Both patients were homozygous for the K136E mutation in SLC17A5, the gene responsible for the free sialic acid storage diseases. Our findings demonstrate that mutations in the SLC17A5 gene have to be considered in patients with hypomyelination, even in the absence of sialuria. Ann Neurol 2009;65:753–757
De novo STXBP1 mutations in mental retardation and nonsyndromic epilepsy
Authors: Hamdan Fadi F. , Piton Amélie , Gauthier Julie , Lortie Anne , Dubeau François , Dobrzeniecka Sylvia , Spiegelman Dan , Noreau Anne , Pellerin Stéphanie , Côté Mélanie , Henrion Edouard , Fombonne Éric , Mottron Laurent , Marineau Claude , Drapeau Pierre , Lafrenière Ronald G. , Lacaille Jean Claude , Rouleau Guy A. , Michaud Jacques L. 
Published: March 2009

AbstractWe sequenced genes coding for components of the SNARE complex (STX1A, VAMP2, SNAP25) and their regulatory proteins (STXBP1/Munc18‐1, SYT1), which are essential for neurotransmission, in 95 patients with idiopathic mental retardation. We identified de novo mutations in STXBP1 (nonsense, p.R388X; splicing, c.169+1G>A) in two patients with severe mental retardation and nonsyndromic epilepsy. Reverse transcriptase polymerase chain reaction and sequencing showed that the splicing mutation creates a stop codon downstream of exon‐3. No de novo or deleterious mutations in STXBP1 were found in 190 control subjects, or in 142 autistic patients. These results suggest that STXBP1 disruption is associated with autosomal dominant mental retardation and nonsyndromic epilepsy. Ann Neurol 2009;65:748–753
Opportunistic infections and other risks with newer multiple sclerosis therapies
Authors: Berger Joseph R. , Houff Sidney 
Published: March 2009

AbstractThe introduction of newer therapies for the treatment of multiple sclerosis has generated considerable optimism. That optimism has been tempered by the potential risks of these therapies, such as the risk for progressive multifocal leukoencephalopathy. A review of the possible causes of reactivation of JC virus in this population has illustrated the need to better understand the untoward effects of monoclonal antibody therapies and other immunomodulatory therapies currently being contemplated for use in multiple sclerosis. These drugs alter the immune response at different sites, and most, if not all, affect more than one aspect of host immunity. Drawing from existing experience with the use of these immunomodulatory therapies in other conditions and that available from the limited experience with multiple sclerosis, we review their potential untoward effects. The latter include a predisposition to opportunistic and community‐acquired infections, an altered response to vaccination, the development of cancers, and the appearance of autoimmune diseases. The identification of progressive multifocal leukoencephalopathy as a risk of therapy is relatively straightforward in light of its rarity and high morbidity and mortality, but a relatively slight increased risk for more common and less disabling disorders may be overlooked. Determining the actual risk frequency for many of these complications will likely require careful postmarketing surveillance. Ann Neurol 2009;65:367–377
Prognostic value of brain diffusion‐weighted imaging after cardiac arrest
Authors: Wijman Christine A. C. , Mlynash Michael , Finley Caulfield Anna , Hsia Amie W. , Eyngorn Irina , Bammer Roland , Fischbein Nancy , Albers Gregory W. , Moseley Michael 
Published: March 2009

AbstractObjectiveOutcome prediction is challenging in comatose postcardiac arrest survivors. We assessed the feasibility and prognostic utility of brain diffusion‐weighted magnetic resonance imaging (DWI) during the first week.MethodsConsecutive comatose postcardiac arrest patients were prospectively enrolled. AWI data of patients who met predefined specific prognostic criteria were used to determine distinguishing apparent diffusion coefficient (ADC) thresholds. Group 1 criteria were death at 6 months and absent motor response or absent pupillary reflexes or bilateral absent cortical responses at 72 hours or vegetative at 1 month. Group 2 criterion was survival at 6 months with a Glasgow Outcome Scale score of 4 or 5 (group 2A) or 3 (group 2B). The percentage of voxels below different ADC thresholds was calculated at 50 × 10−6 mm2/sec intervals.ResultsOverall, 86% of patients underwent DWI. Fifty‐one patients with 62 brain DWIs were included. Forty patients met the specific prognostic criteria. The percentage of brain volume with an ADC value less than 650 to 700 × 10−6mm2/sec best differentiated between Group 1 and Groups 2A and 2B combined (p < 0.001), whereas the 400 to 450 × 10−6mm2/sec threshold best differentiated between Groups 2A and 2B (p = 0.003). The ideal time window for prognostication using DWI was between 49 and 108 hours after the arrest. When comparing DWI in this time window with the 72‐hour neurological examination, DWI improved the sensitivity for predicting poor outcome by 38% while maintaining 100% specificity (p = 0.021).InterpretationQuantitative DWI in comatose postcardiac arrest survivors holds promise as a prognostic adjunct. Ann Neurol 2009;65:394–402
Antibodies produced by clonally expanded plasma cells in multiple sclerosis cerebrospinal fluid
Authors: Owens Gregory P. , Bennett Jeffrey L. , Lassmann Hans , O'Connor Kevin C. , Ritchie Alanna M. , Shearer Andrew , Lam Chiwah , Yu Xiaoli , Birlea Marius , DuPree Cecily , Williamson R. Anthony , Hafler David A. , Burgoon Mark P. , Gilden Don 
Published: March 2009

AbstractObjectiveIntrathecal IgG synthesis, persistence of bands of oligoclonal IgG, and memory B‐cell clonal expansion are well‐characterized features of the humoral response in multiple sclerosis (MS). Nevertheless, the target antigen of this response remains enigmatic.MethodsWe produced 53 different human IgG1 monoclonal recombinant antibodies (rAbs) by coexpressing paired heavy‐ and light‐chain variable region sequences of 51 plasma cell clones and 2 B‐lymphocyte clones from MS cerebrospinal fluid in human tissue culture cells. Chimeric control rAbs were generated from anti‐myelin hybridomas in which murine variable region sequences were fused to human constant region sequences. Purified rAbs were exhaustively assayed for reactivity against myelin basic protein, proteolipid protein, and myelin oligodendrocyte glycoprotein by immunostaining of transfected cells expressing individual myelin proteins, by protein immunoblotting, and by immunostaining of human brain tissue sections.ResultsWhereas humanized control rAbs derived from anti‐myelin hybridomas and anti‐myelin monoclonal antibodies readily detected myelin antigens in multiple immunoassays, none of the rAbs derived from MS cerebrospinal fluid displayed immunoreactivity to the three myelin antigens tested. Immunocytochemical analysis of tissue sections from MS and control brain demonstrated only weak staining with a few rAbs against nuclei or cytoplasmic granules in neurons, glia, and inflammatory cells.InterpretationThe oligoclonal B‐cell response in MS cerebrospinal fluid is not targeted to the well‐characterized myelin antigens myelin basic protein, proteolipid protein, or myelin oligodendrocyte glycoprotein. Ann Neurol 2009;65:639–649
Crystal‐Structure Determination of Powdered Paramagnetic Lanthanide Complexes by Proton NMR Spectroscopy
Authors: Kervern Gwendal , D'Aléo Anthony , Toupet Loïc , Maury Olivier , Emsley Lyndon , Pintacuda Guido 
Published: March 2009

AbstractVerschiebung im Kristall: Die NMR‐Spektroskopie eignet sich für die Strukturbestimmung von mikrokristallinen paramagnetischen Festkörpern ohne Isotopenanreicherung. Paramagnetische Effekte, die unter bestimmten Aufnahmebedingungen in 1H‐NMR‐Spektren auftreten, werden genutzt, um die Konformation der Moleküle im Gitter und ihre Packung in der Festphase abzuleiten. Die Methode wird anhand der Untersuchung einer Familie von Lanthanoidverbindungen vorgestellt (siehe Bild).magnified image
Borreagentien für die orthogonale Funktionalisierung mithilfe von Suzuki‐Miyaura‐Kreuzkupplungen
Authors: Tobisu Mamoru , Chatani Naoto 
Published: March 2009

AbstractEine Frage des Standpunkts: Kontrollierte Suzuki‐Miyaura‐Reaktionen von Substraten mit mehreren potenziellen Kupplungsstellen gelangen, indem die Borsubstituenten angepasst wurden (siehe Schema).magnified image
Iterative In Situ Click Chemistry Creates Antibody‐like Protein‐Capture Agents
Authors: Agnew Heather D. , Rohde Rosemary D. , Millward Steven W. , Nag Arundhati , Yeo Woon‐Seok , Hein Jason E. , Pitram Suresh M. , Tariq Abdul Ahad , Burns Vanessa M. , Krom Russell J. , Fokin Valery V. , Sharpless K. Barry , Heath James R. 
Published: March 2009

AbstractAuf Proteinfang: Iterative Klick‐Reaktionen (siehe Schema des dritten Liganden‐Screenings) und eine Methode zum Aufbau von Bibliotheken mit einer Verbindung pro Kügelchen ermöglichten die Synthese von selektiven, hoch affinen Proteineinfangagentien aus einzelnen Fragmenten. Die resultierenden Liganden sind wasserlöslich und (bio)chemisch sowie thermisch stabil. Durch Kupfer(I)‐katalysierte Cycloadditionen sind sie im Gramm‐Maßstab zugänglich.magnified image
Ordered Poly(p‐phenylene)/Layered Double Hydroxide Ultrathin Films with Blue Luminescence by Layer‐by‐Layer Assembly
Authors: Yan Dongpeng , Lu Jun , Wei Min , Han Jingbin , Ma Jing , Li Feng , Evans David G. , Duan Xue 
Published: March 2009

AbstractLavender layers: A poly(p‐phenylene) anionic derivate and exfoliated Mg‐Al layered double hydroxide monolayers were assembled into ultrathin films with well‐defined blue fluorescence (see picture; the numbers indicate the number of bilayers), long‐range order, and high photostability. These films work as multiple quantum‐well structures for valence electrons.magnified image
Grafting of polypropylene and its potential use as metal ion adsorption resin
Authors: Amaro Lucía Pérez , Rivas Bernabé L. , Coiai Serena , Passaglia Elisa , Augier Sylvain , Ciardelli Francesco 
Published: March 2009

AbstractPolypropylene (PP) was modified by radical grafting of acrylic acid (AA) in the melt by using dicumyl peroxide (DCP) as initiator. To reach a high grafting degree (GD) without substantially modifying PP‐chain structure, a few runs were carried out by employing butyl 3‐(2‐furanyl)propenoate (BFA), which is a coagent able to preserve the molecular weight (MW) of PP macromolecules in the presence of radical grafting reagents. All the samples were extracted with selective solvents to remove unreacted chemicals and free poly(acrylic acid) (PAA), and the GD was accurately determined by using the FTIR methodology. The GD ranged from 1.51 to 4.67 mol %. High‐temperature size permeation chromatography analysis was used to evaluate MW behavior, confirming the control exerted by the presence of BFA on the degradation reactions. DSC, TGA, and SEM analyses were performed to analyze the chemical modification effects on the polymer products' thermal and morphological properties. Finally, selected samples, with a particle size distribution in the range 100–850 μm, were tested as metal ion adsorption resins. Al(III), Cr(III), Zn(II), Cd(II), Pb(II), and Hg(II) were studied, and the highest adsorption efficiency values (in percentage) were obtained for Al(III) (15–20%) and Hg(II) (25–30%). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Piezoresistivity of silicone‐rubber/carbon black composites excited by Ac electrical field
Authors: Wang Shou‐Li , Wang Peng , Ding Tian‐Huai 
Published: March 2009

AbstractFlexible conductive composites were prepared using liquid silicone rubber as a matrix and conductive carbon black (CCB) as a filler, and the filler loading was varied from 1 to 15 phr in mass ratio. The surface conductivity was studied as a function of CCB concentration (1, 5, 10, 15 wt %), frequency in the range from DC to 1 MHz. The AC resistivity of the composites with low CCB concentration was found to be frequency dependent, whereas the composites with high CCB concentration was almost frequency independent. The resistance/impedance drift of the composites with time decreases sharply with the increase of frequency of applied electrical field. The piezoresistivity of the composite with 5 wt % CCB concentration (the upper percolation limit) was studied. It is found that the composite exhibits prominent positive piezoresistivity coefficient effect through the measurement frequency, and the sensitivity becomes steeper with the increase of exciting frequency. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Photografting of methyl methacrylate onto high‐density polyethylene initiated by aliphatic ketones
Authors: Han Jianmei , Wang H. L. 
Published: March 2009

AbstractThe photografting of a water‐insoluble monomer methyl methacrylate (MMA) onto high‐density polyethylene (HDPE) initiated by an aliphatic ketone/water/alcohol initiating system has been reported. The aliphatic ketones, such as acetone, butanone, and cyclohexanone, could effectively initiate the grafting reaction when they were mixed with water and ethanol to form homogeneous aliphatic ketone/water/ethanol mixed solvents that could dissolve the water‐insoluble monomer. The nature of aliphatic ketone affected the grafting; at the same aliphatic ketone/water/ethanol volume ratio, the grafting system containing acetone or butanone always led to a higher extent of grafting than that containing cyclohexanone. Water also played a very important role in the grafting reaction; in the tested range, the rate of formation of grafted PMMA on HDPE increased with the increase of water : volume ratio. The grafting of MMA carried out in 5 acetone/40 water/55 ethanol mixed solvent led to the highest extent of grafting. ATR‐FTIR characterizations of the grafted samples proved the successful grafting of MMA onto HDPE. SEM investigations of the HDPE surfaces grafted in different aliphatic ketone/water/ethanol mixed solvents indicate the morphologies of grafted surfaces varied with the mixed solvents used. This study broadened the application fields of the aliphatic ketone/water/alcohol initiating system for photografting. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009