bluuebunny/crossref_metadata_2025_split huggingface dataset:
Imaging biomarkers in multiple sclerosis
Authors: Filippi M. , Agosta F. 
Published: March 2010

AbstractRecent years have witnessed impressive advances in the use of magnetic resonance imaging (MRI) for the assessment of patients with multiple sclerosis (MS). Complementary to the clinical evaluation, conventional MRI provides crucial pieces of information for the diagnosis of MS. However, the correlation between the burden of lesions observed on conventional MRI scans and the clinical manifestations of the disease remains weak. The discrepancy between clinical and conventional MRI findings in MS is explained, at least partially, by the limited ability of conventional MRI to characterize and quantify the heterogeneous features of MS pathology. Other quantitative MR‐based techniques, however, have the potential to overcome such a limitation of conventional MRI. Indeed, magnetization transfer MRI, diffusion tensor MRI, proton MR spectroscopy, and functional MRI are contributing to elucidate the mechanisms that underlie injury, repair, and functional adaptation in patients with MS. Such techniques are likely to benefit from the use of high‐field MR systems and thus allow in the near future providing additional insight into all these aspects of the disease. This review summarizes how MRI is dramatically changing our understanding of the factors associated with the accumulation of irreversible disability in MS and highlights the reasons why they should be used more extensively in studies of disease evolution and clinical trials. J. Magn. Reson. Imaging 2010;31:770–788. ©2010 Wiley‐Liss, Inc.
Human brain MR spectroscopy thermometry using metabolite aqueous‐solution calibrations
Authors: Covaciu Lucian , Rubertsson Sten , Ortiz‐Nieto Francisco , Ahlström Håkan , Weis Jan 
Published: March 2010

AbstractPurpose:To estimate absolute brain temperature using proton MR spectroscopy (1H‐MRS) and mean brain–body temperature difference of healthy human volunteers.Materials and Methods:Chemical shift difference between temperature‐dependent water spectral line position and temperature‐stable metabolite spectral reference was used for the estimations of absolute brain temperature. Temperature calibrations constants were obtained from the spectra of the N‐acetyl aspartate (NAA line at ∼2.0 ppm), glycero‐phosphocholine (GPC line at ∼3.2 ppm), and creatine (Cr line at ∼3.0 ppm) aqueous solutions with pH values within physiologically pertinent ranges. Single‐voxel PRESS sequence (TR/TE 2000/80 ms) was used for this purpose. Brain temperature was determined by averaging the temperatures computed from water‐Cho, water‐Cr, and water‐NAA chemical shift differences.Results:The mean brain temperature of 18 healthy volunteers was 38.1 ± 0.4°C and mean brain–body (rectal) temperature difference was 1.3 ± 0.4°C.Conclusion:Improved accuracy of the temperature constants and averaging the temperatures computed from water‐Cho, water‐Cr, and water‐NAA chemical shift differences increased the reliability of the brain temperature estimations. J. Magn. Reson. Imaging 2010;31:807–814. ©2010 Wiley‐Liss, Inc.
Automated segmentation of the aorta from phase contrast MR images: Validation against expert tracing in healthy volunteers and in patients with a dilated aorta
Authors: Herment Alain , Kachenoura Nadjia , Lefort Muriel , Bensalah Mourad , Dogui Anas , Frouin Frédérique , Mousseaux Elie , De Cesare Alain 
Published: March 2010

AbstractPurpose:To assess if segmentation of the aorta can be accurately achieved using the modulus image of phase contrast (PC) magnetic resonance (MR) acquisitions.Materials and Methods:PC image sequences containing both the ascending and descending aorta of 52 subjects were acquired using three different MR scanners. An automated segmentation technique, based on a 2D+t deformable surface that takes into account the features of PC aortic images, such as flow‐related effects, was developed. The study was designed to: 1) assess the variability of our approach and its robustness to the type of MR scanner, and 2) determine its sensitivity to aortic dilation and its accuracy against an expert manual tracing.Results:Interobserver variability in the lumen area was 0.59 ± 0.92% for the automated approach versus 10.09 ± 8.29% for manual segmentation. The mean Dice overlap measure was 0.945 ± 0.014. The method was robust to the aortic size and highly correlated (r = 0.99) with the manual tracing in terms of aortic area and diameter.Conclusion:A fast and robust automated segmentation of the aortic lumen was developed and successfully tested on images provided by various MR scanners and acquired on healthy volunteers as well as on patients with a dilated aorta. J. Magn. Reson. Imaging 2010;31:881–888. ©2010 Wiley‐Liss, Inc.
Induced magnetic force in human heads exposed to 4 T MRI
Authors: Wang Ruiliang , Wang Gene‐Jack , Goldstein Rita Z. , Caparelli Elisabeth C. , Volkow Nora D. , Fowler Joanna S. , Tomasi Dardo 
Published: March 2010

AbstractPurpose:To map the distribution of the magnetic force induced in the human head during magnetic resonance imaging (MRI) at 4 T for a large group of healthy volunteers.Materials and Methods:The magnetic field distribution in the head of 100 men and 18 women was mapped using phase mapping techniques. Statistical parametric mapping methods using a family‐wise error (FWE) corrected threshold P < 0.05 and region‐of‐interest analyses were used to assess the significance of the results.Results:Eyeballs, orbitofrontal and temporal cortices, subcallosal gyrus, anterior cingulate, midbrain, and brainstem (pons) are the brain regions most susceptible to magnetic force. The strength of the magnetic force density in the head was lower than 11.5 ± 5.3 N/m3 (right eyeball). The strength of the magnetic force density induced in occipital cortex varied linearly with the x‐rotation (pitch) angle.Conclusion:We found that the induced magnetic force is highly significant in the eyeballs, orbitofrontal and temporal cortices, subcallosal gyrus, anterior cingulate as well as midbrain and brainstem (pons), regardless of subjects' age or gender. The maximum induced magnetic force was 6 × 105 times weaker than the gravitational force; thus, biological effects of the magnetic force during imaging are not expected to be significant. J. Magn. Reson. Imaging 2010;31:815–820. ©2010 Wiley‐Liss, Inc.
Hypoxia‐like effect of Cobalt Chromium alloy micro particles on fibroblasts in vitro
Authors: Madathil Bernadette K. , Lin Qingsong , Hew Choy‐Leong , Mohanty Mira 
Published: March 2010

AbstractPeriprosthetic osteolysis leading to asceptic loosening remains the primary cause of failure of joint replacement. Although many inflammatory cell types have been implicated, the exact pathomechanisms of asceptic loosening have not been delineated. In the present study we have adopted a proteomic approach to elucidate the initial signals that are expressed to particulate material, using an in vitro cell culture system. Human lung fibroblasts MRC‐5 were cultured with Cobalt Chromium (CoCr ASTM F‐75, 1–7 µm) particles. Cells were harvested after 72 h incubation and total cellular proteins extracted for downstream analysis via 2D Gel Electrophoresis and tandem mass spectrometry using MALDI‐TOF‐TOF‐MS. Thirteen protein spots showed greater than twofold increase, following 72 h incubation of fibroblast with CoCr particles. Four of these proteins were identified by tandem mass spectrometry. These were Annexin II, Pyruvate kinase, Triose phosphate isomerase, and N‐myc downstream regulated gene 1 protein. Cobalt is a hypoxia mimicking agent and N‐myc downstream regulated gene 1 protein, Triose phosphate isomerase, Pyruvate kinase, and Annexin II are important hypoxia regulated gene products that are found to be over expressed in cellular oxidative stress response. Our data indicates that exposure of fibroblast to CoCr alloy induces the transition of these cells into a hypoxia like state and oxidative stress even in normoxic culture conditions. The study reflects the possibility of the presence of a hypoxic environment in the periprosthetic tissue surrounding metallic implants. Published by Wiley Periodicals, Inc. J Orthop Res 28:1360–1367, 2010
Extractionless non‐hydrolysis surface‐enhanced Raman spectroscopic detection of historical mordant dyes on textile fibers
Authors: Jurasekova Z. , del Puerto E. , Bruno G. , García‐Ramos J. V. , Sanchez‐Cortes S. , Domingo C. 
Published: March 2010

AbstractAlizarin and carminic acid have been detected in reference wool and linen fibers dyed with madder and cochineal, respectively, through surface‐enhanced Raman scattering (SERS) measurements carried out directlyon the fiber, without previous hydrolysis of the mordant‐dye complex. For such purpose, Ag nanoparticles were produced and immobilizedin situvia the laser photoreduction of a silver nitrate aqueous solution in contact with the fiber. Control SERS spectra of pure dyes (alizarin, purpurin and carminic acid, as well as of mixtures of the first two) on similar Ag nanoparticles were also obtained. The method has been applied to one archeological Coptic textile (6th–8th A.D.) of Egyptian origin, where alizarin has been clearly identified. Other mordant dyes of the flavonoids family (luteolin, apigenin and flavonols) have also been identified by the same SERS method in wool fibers dyed with natural plants, mainly used in Central and South America (Dyer's greenweed, old fustic, onion and chilca) following pre‐Columbian dying recipes. Copyright © 2010 John Wiley & Sons, Ltd.
The role of protective self‐cognitions in the relationship between childhood trauma and later resource loss
Authors: Walter Kristen H. , Horsey Katie J. , Palmieri Patrick A. , Hobfoll Stevan E. 
Published: March 2010

AbstractThe authors examined a prospective model investigating posttraumatic stress disorder (PTSD) symptoms and protective self‐cognitions (self‐esteem and self‐efficacy) with later resource loss among 402 inner‐city women who experienced childhood abuse. They predicted that women with PTSD may fail to develop or sustain protective self‐cognitions that could protect against future stress. Results from the hypothesized model suggest that child abuse was associated with greater PTSD symptoms and later resource loss. PTSD symptoms were also related to protective self‐cognitions, which, in turn, were associated with less resource loss. The authors also examined an alternative model exploring the relationship between resource loss and later PTSD symptoms. Findings allude to the relationship of risk and resiliency variables among women with childhood trauma histories.
Injectable tissue‐engineered bone repair of a rat calvarial defect
Authors: Stephan Scott J. , Tholpady Sunil S. , Gross Brian , Petrie‐Aronin Caren E. , Botchway Edward A. , Nair Lakshmi S. , Ogle Roy C. , Park Stephen S. 
Published: March 2010

AbstractObjectives/Hypothesis:Advances in bone repair have focused on the minimally‐invasive delivery of tissue‐engineered bone (TEB). A promising injectable biopolymer of chitosan and inorganic phosphates was seeded with mesenchymal stem cells (MSCs) and a bone growth factor (BMP‐2), and evaluated in a rat calvarial critical size defect (CSD). Green fluorescent protein (GFP)‐labeled MSCs are used to evaluate patterns of cell viability and proliferation.Study Design:Prospective, controlled trial in an animal model.Methods:In 30 male rats, 8‐mm calvarial CSDs were created, and divided into five groups of six animals each. In the experimental groups, the defects were injected with either chitosan gel, gel loaded with MSCs (0.3 × 106 cells/defect), gel loaded with BMP‐2 (2 μg/defect), or gel loaded with both MSC and BMP‐2. In the control group, the defect was left untreated. At 4 weeks, in vivo microcomputed tomography (micro‐CT) analysis was performed. At 8 weeks, calvarial specimens were examined by micro‐CT, histology, and immunohistochemistry.Results:New areas of bone growth were seen in the defects of all treated animals. Micro‐CT analysis revealed a significant (P < .001) time‐dependent increase in the regeneration of bone volume and bone area in defects treated with gel/MSC/BMP‐2 as compared to all other groups. Histological analysis confirmed this difference. GFP–labeled TEB was detected within the areas of new bone, indicating cell viability and contribution to new bone growth by the injected MSC.Conclusions:This study demonstrates that an injectable form of TEB using a chitosan gel, MSC, and BMP‐2 can enhance bone formation in a rat calvarial CSD. Laryngoscope, 2010
Chemical Modification of Hydrophobic Block in Poly(Ethylene Oxide) Poly(Caprolactone) Based Nanocarriers: Effect on the Solubilization and Hemolytic Activity of Amphotericin B
Authors: Falamarzian Arash , Lavasanifar Afsaneh 
Published: March 2010

AbstractThe aim of this study was to develop methoxy poly(ethylene oxide)‐b‐poly(ε‐caprolactone) (MePEO‐b‐PCL) containing stearyl (St) substituents on PCL, and assess the efficacy of nanocarriers formed from this structure in comparison to unmodified MePEO‐b‐PCL and those with carboxyl substitutes on PCL on the solubilization and delivery of Amphotericin B (AmB). Prepared block copolymers were characterized for their molecular weight by 1H NMR and gel permeation chromatography. The self‐assembly of synthesized MePEO‐b‐PStCL to spherical particles of nanometer size range was shown by dynamic light scattering as well as electron and atomic force microscopy. Encapsulated AmB showed a reduction in its hemolytic activity against rat red blood cells in comparison to the commercial formulation of AmB, Fungizone.magnified image
Solid‐State NMR Characterization of the Multiphase Structure of Polypropylene In‐reactor Alloy
Authors: Zhu Haijin , Graf Robert , Hou Guangjin , Zhao Ying , Wang Dujin , Spiess Hans W. 
Published: March 2010

AbstractA variety of solid‐state NMR techniques were used to characterize the chain dynamics, miscibility and the micro‐phase structure of a polypropylene (PP) in‐reactor alloy system. The alloy was physically separated into three fractions, and the molecular dynamics and relaxation behavior of the pure fractions was then compared with the components in the alloy to achieve comprehensive understanding of the phase structure of the PP in‐reactor alloy. The miscibility among different components of the alloy was studied by the rotational frame spin‐lattice relaxation time. Proton spin‐diffusion methods were used to quantify the domain thicknesses of different regions in the alloy. The results show that the alloy is composed of three phases, namely, a homo‐polyethylene (HPE) matrix, a homo‐polypropylene (HPP) dispersed phase, and a linear low‐density polyethylene (LLDPE) interphase. The thickness of the LLDPE interphase is estimated to be 7.7 nm at room temperature, and changes dramatically with temperature. Finally, based on all the solid‐state NMR results, a model for the micro‐phase‐structure of the PP in‐reactor alloy is proposed, and a correlation between the micro‐phase structure and the excellent mechanical property is established.magnified image
High Temperature Semibatch Free Radical Copolymerization of Styrene and Butyl Acrylate
Authors: Wang Wei , Hutchinson Robin A. 
Published: March 2010

AbstractSummary: High temperature semibatch free radical solution copolymerizations of n‐butyl acrylate (BA) and styrene (ST) were carried out over a range of copolymer composition. The significant increase in experimental polymer weight‐average molecular weight with time, as well as the shift in the entire polymer molecular weight distribution, is explained by assuming fast β‐scission of BA midchain radicals with an adjacent styrene unit, followed by subsequent addition of the resultant macromonomer to growing radicals. A mechanistic model including backbiting and β‐scission, macronomer incorporation, long‐chain branching, and propagation and termination penultimate effects was constructed in Predici; the model provides a good representation of the experimental data using rate coefficients taken from literature.
In Line Spectroscopic Investigation of Fluorinated Copolymer Synthesis in Supercritical Carbon Dioxide
Authors: Möller Eléonore , Schreiber Ulrike , Beuermann Sabine 
Published: March 2010

AbstractSummary: In‐line Fourier Transform – near infrared (FT‐NIR) spectroscopy is a very elegant method to follow conversion as well as phase behaviour throughout a reaction. It was applied to two examples of homogeneous phase syntheses of fluorinated copolymers in supercritical carbon dioxide (scCO2). The conventional free radical copolymerization of vinylidene fluoride (VDF) and hexafluoropropene (HFP) on the one hand side, and the Activators Generated by Electron Transfer (AGET) Atom Transfer Radical Polymerization (ATRP) of F‐decene (1H‐1H, 2H perfluoro‐1‐decene) and tBA (tert‐butyl acrylate) on the other hand side were studied. Poly(VDF‐co‐HFP) were synthesized at 75 and 100 °C at pressures above 800 bar to remain in solution, even at high VDF contents. The reactivity ratios, r, were determined from a small number of experiments using the entire conversion vs. time data from in‐line FT‐NIR measurements. The estimated values are rVDF = 4.3 and rHFP = 0.1. In the case of poly(F‐decene‐co‐tBA), a fluorinated macroligand was introduced for AGET ATRP. Molecular weights between 10000 and 40000 g/mol and polydispersities between 1.1 and 2.1 were obtained while remaining in homogeneous phase. Reactivity ratios were determined as rF‐decene = 0.02 and rtBA = 9.1.
Industrial Production of Fluoroelastomer Nanocomposites by Microemulsion Polymerization followed by Co‐Coagulation
Authors: Apostolo M. , Chernysheva L. , Fantoni M. , Verneau B. 
Published: March 2010

AbstractSummary: In this paper synthesis and properties of fluoroelastomer nano‐composites are discussed. The production technology is based on two steps: first, high solid content nano‐latex of a semi‐crystalline perfluoropolymer is produced by means of a special microemulsion polymerization; then, co‐coagulation of this latex with a fluoroelastomer latex leads to the formation of the nano‐composite. When properly designed, fluoroelastomer nano‐composites develop properties that are better than those of each individual polymer of the blend. This paper is particularly focused on the remarkable values of reinforcement and permeability that can be achieved with these nano‐composites. A simple model is developed to better understand the origin of such properties. The model provides a possible explanation of the observed increase in nano‐composite properties when the size of the dispersed phase is below 100 nm, that is in the nano‐scale region. Finally, selected examples of industrial application of these nano‐composites are briefly discussed.
Biopolymer Synthesis Catalyzed by Tailored Lipases
Authors: Sandoval Georgina , Rivera Ivanna , Barrera‐Rivera Karla A. , Martínez‐Richa Antonio 
Published: March 2010

AbstractSummary: Enzyme‐catalyzed synthesis of biopolymers is a growing area of green chemistry because the exquisite selectivity and control of the polymer structure allowed by the enzymatic synthesis. In addition, the metal traces of chemical catalysts are avoided, being this feature particularly useful in biomedical applications. Lipases are remarkable catalysts and they are efficient in the synthesis of several kinds of biopolymers. However, one of the limitations of the industrial application of lipase‐catalyzed polymerizations is the cost of commercial immobilized lipases. To overcome this drawback, in this work we present some cheap and simple strategies to produce and obtain immobilized lipases, as well as some examples of biopolymer synthesis using these tailored lipases.
DC Electrical Study of Modified PMMA, PVC and their Blend
Authors: Soman Vijay V. , Kelkar Deepali S. 
Published: March 2010

AbstractSummary: Thin films of high molecular weight PMMA, PVC and their blend were prepared with solution cast method. Further they were modified by adding Camphor Sulphonic Acid (CSA) to them. DSC studies indicate single glass transition temperature (Tg) for unmodified as well as modified blends indicating the miscibility of polymers. FTIR studies show the interaction between CSA‐PVC, CSA‐PMMA, CSA‐(PVC+PMMA) blend. The D.C. electrical study was carried out at various temperatures from room temperature (307 K) to 373 K. After modification the variation of DC conductivity (σ) is found to decrease in PVC and the PVC‐PMMA blend whereas it is found to increase in PMMA with rise in temperature.
Comparison Between Different Syntesis Methods of PMMA/HA Using Ultrasonic Radiation
Authors: Albano C. , Parra C. , González G. 
Published: March 2010

AbstractSummary:The use of PMMA as dental and osseous cement and also in the fabrication of intraocular lenses has been widely reported. The combination of its excellent properties with those of hydroxyapatite (HA) to form a composite material, can result in very interesting properties as a biomaterial. The key is to obtain a good filler dispersion and interface bonding. Ultrasonic radiation seems to be a very versatile method for the synthesis of these materials, since the use of conventional initiators can be avoided, the filler dispersion improved and the interface interaction can be promoted. In the present work PMMA/HA composite materials were prepared by three different synthesis routes using ultrasonic radiation, in order to study the effect of the synthesis method on the final microstructure.Method I:in situsynthesis of PMMA and HA, under ultrasonic radiation by emulsion polymerization of MMA and HA precursors.Method II:in situsynthesis of HA, (from its precursors) by high frequency ultrasound in commercial PMMA solutionMethod III:in situpolymerization of MMA under high frequency ultrasonic radiation and adding HA to the solution andMethod IVMixing of hydroxyapatite nanocrystals, in different proportions, in a solution of commercial PMMA, by different periods from 10 min to 7 h, under low frequency (conventional) ultrasonic radiation, to compare the effect of high frequency and conventional ultrasound radiation. The different materials were characterized by FTIR, SEM, TEM, DRX,1H NMR and TGA. The results showed that, all the composites prepared byin situsynthesis showed an interaction between HA and PMMA, manifested by a bonding of the phosphate groups with the polar groups of the polymer matrix observed by FTIR. On the other hand, when the synthesis was carried out simultaneously adding HA and PMMA precursors a inhibition of the polymerization reaction of MMA was observed.
Evaluation of Biodegradability of Different Blends of Polystyrene and Starch Buried in Soil
Authors: Oliveira C. I. R. , Cunha F. R. , Andrade C. T. 
Published: March 2010

AbstractSummary: Polystyrene/cornstarch blends were prepared by melt‐processing in the presence of maleic anhydride (MA), using an internal mixer as reactor. Scanning electron microscopy (SEM) was used to visualize the blends morphology. Addition of MA contributed to improve interfacial adhesion between the two phases. Soil burial tests were used to investigate biodegradability. Results from samples weight loss, as a function of incubation time, revealed that the increase in the content of starch contributed to increase biodegradability. The results showed that the microbial activity inside the specimens was accelerated in the first 15 days of evaluation. Photographs of the films showed significant differences after 30 days of incubation in soil. SEM was also used to evaluate biodegradation, and revealed fractured surfaces covered with a heterogeneous microorganism community.