bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parkinson's Disease and Alpha Synuclein: Is Parkinson's Disease a Prion‐Like Disorder?
Authors: Olanow C. Warren , Brundin Patrik 
Published: February 2013

ABSTRACTAltered protein handling is thought to play a key role in the etiopathogenesis of Parkinson's disease (PD), as the disorder is characterized neuropathologically by the accumulation of intraneuronal protein aggregates (Lewy bodies and Lewy neurites). Attention has particularly focused on the α‐synuclein protein, as it is the principal component of Lewy pathology. Moreover, point mutations in the α‐synuclein gene cause rare familial forms of PD. Importantly, duplication/triplication of the wild type α‐synuclein gene also cause a form of PD, indicating that increased levels of the normal α‐synuclein protein is sufficient to cause the disease. Further, single nucleotide polymorphisms in the α‐synuclein gene are associated with an increased risk of developing sporadic PD. Recent evidence now suggests the possibility that α‐synuclein is a prion‐like protein and that PD is a prion‐like disease. Within cells, α‐synuclein normally adopts an α‐helical conformation. However, under certain circumstances, the protein can undergo a profound conformational transition to a β‐sheet–rich structure that polymerizes to form toxic oligomers and amyloid plaques. Recent autopsy studies of patients with advanced PD who received transplantation of fetal nigral mesencephalic cells more than a decade earlier demonstrated that typical Lewy pathology had developed within grafted neurons. This suggests that α‐synuclein in an aberrantly folded, β‐sheet–rich form had migrated from affected to unaffected neurons. Laboratory studies confirm that α‐synuclein can transfer from affected to unaffected nerve cells, where it appears that the misfolded protein can act as a template to promote misfolding of host α‐synuclein. This leads to the formation of larger aggregates, neuronal dysfunction, and neurodegeneration. Indeed, recent reports demonstrate that a single intracerebral inoculation of misfolded α‐synuclein can induce Lewy‐like pathology in cells that can spread from affected to unaffected regions and can induce neurodegeneration with motor disturbances in both transgenic and normal mice. Further, inoculates derived from the brains of elderly α‐synuclein–overexpressing transgenic mice have now been shown to accelerate the disease process when injected into the brains of young transgenic animals. Collectively, these findings support the hypothesis that α‐synuclein is a prion‐like protein that can adopt a self‐propagating conformation that causes neurodegeneration. We propose that this mechanism plays an important role in the development of PD and provides novel targets for candidate neuroprotective therapies. © 2013 Movement Disorder Society
Induced clustered nanoconfinement of superparamagnetic iron oxide in biodegradable nanoparticles enhances transverse relaxivity for targeted theranostics
Authors: Ragheb Ragy R. T. , Kim Dongin , Bandyopadhyay Arunima , Chahboune Halima , Bulutoglu Beyza , Ezaldein Harib , Criscione Jason M. , Fahmy Tarek M. 
Published: February 2013

PurposeCombined therapeutic and diagnostic agents, “theranostics” are emerging valuable tools for noninvasive imaging and drug delivery. Here, we report on a solid biodegradable multifunctional nanoparticle that combines both features.MethodsPoly(lactide‐co‐glycolide) nanoparticles were engineered to confine superparamagnetic iron oxide contrast for magnetic resonance imaging while enabling controlled drug delivery and targeting to specific cells. To achieve this dual modality, fatty acids were used as anchors for surface ligands and for encapsulated iron oxide in the polymer matrix.ResultsWe demonstrate that fatty acid modified iron oxide prolonged retention of the contrast agent in the polymer matrix during degradative release of drug. Antibody‐fatty acid surface modification facilitated cellular targeting and subsequent internalization in cells while inducing clustering of encapsulated fatty‐acid modified superparamagnetic iron oxide during particle formulation. This induced clustered confinement led to an aggregation within the nanoparticle and, hence, higher transverse relaxivity, r2, (294 mM−1 s−1) compared with nanoparticles without fatty‐acid ligands (160 mM−1 s−1) and higher than commercially available superparamagnetic iron oxide nanoparticles (89 mM−1 s−1).ConclusionClustering of superparamagnetic iron oxide in poly(lactide‐co‐glycolide) did not affect the controlled release of encapsulated drugs such as methotrexate or clodronate and their subsequent pharmacological activity, thus highlighting the full theranostic capability of our system. Magn Reson Med 70:1748–1760, 2013. © 2013 Wiley Periodicals, Inc.
Water/fat‐resolved whole‐heart Dixon coronary MRA: An initial comparison
Authors: Börnert Peter , Koken Peter , Nehrke Kay , Eggers Holger , Ostendorf Peter 
Published: February 2013

PurposeTo improve coronary vessel visualization in whole‐heart coronary magnetic resonance angiography (CMRA), fat suppression is typically applied. However, recent studies have shown that cardiac fat can also have diagnostic value. To enhance CMRA image quality by improved fat suppression and to provide additionally fat‐only information highly resolved, dual‐echo Dixon CMRA approaches have been developed.MethodsIn this pilot study, approved by the institutional review board, 30 patients were investigated comparing whole‐heart T1‐weighted dual‐echo Dixon CMRA to conventional whole‐heart fat‐suppressed balanced fast field echo CMRA, integrated into a routine clinical protocol that includes the administration of gadolinium for perfusion and late enhancement measurements. Signal‐to‐noise‐ratio, contrast‐to‐noise‐ratio, and image quality were analyzed.ResultsDual‐echo Dixon significantly (P<0.000001) improved image quality compared with conventional fat‐suppressed balanced fast field echo CMRA. Signal‐to‐noise‐ratio and contrast‐to‐noise‐ratio were found to be comparable when balanced fast field echo was performed before gadolinium and dual‐echo Dixon fast field echo after gadolinium administration.ConclusionDual‐echo Dixon can help to improve whole‐heart CMRA image quality significantly. The additional whole‐heart fat information delivered by this approach can support a number of new clinical studies addressing the diagnostic and the predictive value of intramyocardial and extramyocardial fatty deposits. Magn Reson Med 71:156–163, 2014. © 2013 Wiley Periodicals, Inc.
Inspection games with local and global allocation bounds
Authors: Deutsch Yael , Golany Boaz , Goldberg Noam , Rothblum Uriel G. 
Published: February 2013

AbstractThis article discusses a two‐player noncooperative nonzero‐sum inspection game. There are multiple sites that are subject to potential inspection by the first player (an inspector). The second player (potentially a violator) has to choose a vector of violation probabilities over the sites, so that the sum of these probabilities do not exceed one. An efficient method is introduced to compute all Nash equilibria parametrically in the amount of resource that is available to the inspector. Sensitivity analysis reveals nonmonotonicity of the equilibrium utility of the inspector, considered as a function of the amount of resource that is available to it; a phenomenon which is a variant of the well‐known Braess paradox. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013
miR‐29a inhibition normalizes HuR over‐expression and aberrant AU‐rich mRNA stability in invasive cancer
Authors: Al‐Ahmadi Wijdan , Al‐Ghamdi Maha , Al‐Souhibani Norah , Khabar Khalid SA 
Published: February 2013

AbstractThe activities of RNA‐binding proteins are perturbed in several pathological conditions, including cancer. These proteins include tristetraprolin (TTP, ZFP36) and HuR (ELAVL1), which respectively promote the decay or stability of adenylate‐uridylate‐rich (AU‐rich) mRNAs. Here, we demonstrated that increased stabilization and subsequent over‐expression of HuR mRNA were coupled to TTP deficiency. These findings were observed in breast cancer cell lines with an invasive phenotype and were further confirmed in ZFP36‐knockout mouse fibroblasts. We show that TTP–HuR imbalance correlated with increased expression of AU‐rich element (ARE) mRNAs that code for cancer invasion genes. The microRNA miR‐29a was abundant in invasive breast cancer cells when compared to non‐tumourigenic cell types. When normal breast cells were treated with miR‐29a, HuR mRNA and protein expression were up‐regulated. MiR‐29a recognized a seed target in the TTP 3′ UTR and a cell‐permeable miR‐29a inhibitor increased TTP activity towards HuR 3′ UTR. This led to HuR mRNA destabilization and restoration of the aberrant TTP–HuR axis. Subsequently, the cancer invasion factors uPA, MMP‐1 and MMP‐13, and cell invasiveness, were decreased. The TTP:HuR mRNA ratios were also perturbed in samples from invasive breast cancer patients when compared with normal tissues, and were associated with invasion gene expression. This study demonstrates that an aberrant ARE‐mediated pathway in invasive cancer can be normalized by targeting the aberrant and functionally coupled TTP–HuR axis, indicating a potential therapeutic approach. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
An elaboration on the shear characterization of dry woven fabrics using trellising tests
Authors: Komeili M. , Milani A.S. 
Published: February 2013

AbstractMaterial characterization of woven fabric composites in dry form is one of the most crucial steps prior to the design and optimization of composite manufacturing processes. High stiffness of yarns under axial tension and low stiffness under in‐plane shear makes the latter the dominant deformation mode during draping of woven fabrics. Bias‐extension (BE) and shear frame (SF) tests are two widely used experimental setups for the characterization of woven fabrics under the shear (also called trellising) mode. This article outlines two general approaches for the characterization and normalization of data collected from the above standard tests. The first approach is based on the total energy absorbed by the fabric specimen along with the total work induced by the external force on the moving head of the tensile test machine. The second approach uses a variational formulation along with the principle of virtual work. Using both approaches, it is shown how, in the BE test, an auxiliary specimen with a different aspect ratio can be used to cope with the problem of nonuniform deformation (formation of three different shear regions) in the specimens. To illustrate the application of both methods, they are applied to predict in‐plane shear stiffness of a glass/PP plain weave under SF and BE tests. It is suggested that the shear stress can be used as a normalized parameter to compare data from different trellising tests. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
Effect of plasma modification on the mechanical properties of carbon fiber/phenolphthalein polyaryletherketone composites
Authors: Li Wei , Yao Shu Yong , Ma Ke Ming , Chen Ping 
Published: February 2013

AbstractA study was carried out to investigate the effect of plasma modification on the mechanical properties of carbon fiber/phenolphthalein polyaryletherketone composites. The influence of oxygen plasma treatment on the surface properties of carbon fibers was investigated by X‐ray photoelectron spectroscopy and atomic force microscopy. The results indicated that oxygen plasma treatment was capable of increasing the concentrations of the oxygen‐containing groups of the carbon fiber surface as well as enhancing surface roughness. Both the chemical bonding and mechanical interlocking gave rise to an increase of the interlaminar shear strength of composite. Scanning electron microscope photographs showed that the destruction mode of composites was changed after the carbon fibers were treated by oxygen plasma. The results also indicated that the flexural properties of plasma‐treated carbon fiber composites were improved. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
Investigation of the effect of different silane coupling agents on mechanical performance of basalt fiber composite laminates with biobased epoxy matrices
Authors: España J.M. , Samper M.D. , Fages E. , Sánchez‐Nácher L. , Balart R. 
Published: February 2013

AbstractIn recent years, it has been detected an increased interest in the development of materials from renewable resources. This trend has been intensified in the industrial sector where significant efforts have been made in this field in order to adapt these natural fibers to conventional industrial processes and applications. As a result, research has been done into developing new thermoplastic matrices which are compatible with this type of reinforcing fibers. This study evaluates the influence of different coupling agents based on silanes, on the mechanical properties of composite laminates made from a biobased epoxy resin matrix and basalt fabric by using vacuum assisted resin transfer moulding. The curing behavior of the biobased epoxy resin was evaluated by differential scanning calorimetry (DSC), gel point determination, and ionic conductivity. The evaluation of mechanical properties was done by tensile, flexural, impact, and hardness tests. Compatibility between basalt fibers and epoxy resin generally has managed to increase through the addition of silanes, after the addition of these, their mechanical properties are substantially improved compared to the sample without silane treatment, obtaining this way an easily processable material, with good properties and capable of competing with materials with petroleum‐based epoxy resins. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
Orientated CNT‐polypropylene nanocomposite films made from extruded monofilaments
Authors: Tanami Golan A. , Wachtel Ellen , Marom Gad 
Published: February 2013

AbstractIn this study, a method for making an orientated polymer nanocomposite film was developed. Melt‐drawn nanocomposite monofilaments of isotactic polypropylene and acicular nanofillers, i.e. carbon nanotubes (CNT) or vapor grown carbon nanofibers (VGCF), were prepared and characterized from the aspect of polymer chain orientation, mechanical properties, and overall morphology. A marked improvement in mechanical properties was observed as a function of the addition of CNT, increasing draw down ratio (DDR) and annealing. Nanocomposite films were prepared from drawn monofilaments by hot‐pressing under low pressure in order to maintain the orientation of the monofilaments. Wide angle X‐ray diffraction showed a high degree of residual orientation in the films. Electron microscopy (high‐resolution scanning electron microscopy, transmission electron microscopy) unexpectedly revealed that the CNT‐matrix interface is amorphous. However, differential scanning calorimetry found no measurable influence of the CNT on the overall crystallinity as determined by the enthalpy of melting of the matrix. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
Synthesis, thermal, and photocrosslinking studies of thermotropic liquid crystalline poly(benzylidene‐ether)esters containing α,β‐unsaturated ketone moiety in the main chain
Authors: Muthusamy Athianna , Balaji Krishnasamy , Murugavel Salem Chandrasekaran 
Published: February 2013

AbstractA series of poly(benzylidene‐ether)esters containing a photoreactive benzylidene chromophore in the main chain were synthesized from 2,6‐bis(4‐hydroxy‐3‐methoxybenzylidene)cyclohexanone (BHMBCH) with various aliphatic and aromatic diacid chlorides by an interfacial polycondensation technique. The intrinsic viscosity of the synthesized homo and copolymers determined by Ubbelohde viscometer was found to be 0.12 to 0.17 dL/g. The molecular structure of the monomer and polymers was confirmed by FT‐IR, 1H NMR, and 13C NMR spectral analyses. These polymers were studied for their thermal stability and photochemical properties. Thermal properties were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It was found that the polymers were stable up to 280 °C and start degrading thereafter. Increase in acid methylene spacer length decreased the thermal stability. The self‐extinguishing property of the synthesized polymers was studied by calculating the limiting oxygen index (LOI) value using a Van Krevelen's equation. The influence of the length of methylene spacer on phase transition was investigated using DSC and odd‐even effect has been observed. Hot‐stage optical polarizing microscopic (HOPM) study showed that most of the polymers exhibited birefringence and opalescence properties. The photolysis of liquid crystalline poly(benzylidene‐ether)esters revealed that α,β‐unsaturated ketone moiety in the main chain dimerises through 2π + 2π cycloaddition reaction to form a cyclobutane derivative and leads to crosslinking. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Ion transport in sulfonated polymers
Authors: Park Moon Jeong , Kim Sung Yeon 
Published: February 2013

AbstractAs the focus on proton exchange fuel cells continues to escalate in the era of alternative energy systems, the rational design of sulfonated polymers has emerged as a key technique for enhancing device efficiency. Although the synthesis and characterization of a wide variety of sulfonated polymers have been extensively reported over the last decade, quantitative understanding of the factors governing the ion transport properties of these materials is in its infancy. In this article, we describe the current understanding of the thermodynamics and ion transport in sulfonated polymers. Various strategies for accessing improved transport properties of sulfonated polymers are presented by focusing on their structure‐property relationship. The major accomplishment of obtaining well‐defined morphologies for these sulfonated polymers is highlighted as a novel means of controlling the transport properties. Recent studies on the thermodynamics, morphologies, and anhydrous transport properties of sulfonated block copolymers comprising ionic liquids, geared towards high temperature polymer electrolyte membranes as a prospective technology, are also expounded. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013
Design and fabrication of thermally stable nanoparticles for well‐defined nanocomposites
Authors: Yoo Misang , Kim Seyong , Bang Joona 
Published: February 2013

AbstractThe nanocomposites consisted of polymer and nanoparticles (NPs) have been regarded as one of core materials in the nanotechnology. From the practical viewpoint, the heat treatment is often required in many nanocomposite fabrication processes. However, some NPs such as gold NPs exhibit the low thermal stability due to the dissociation of ligands from the nanoparticle surface at elevated temperature, limiting their use in many applications. Herein, we provide an overview of the recent efforts in strategies for the design and fabrication of inorganic NPs which have enhanced thermal stability. The recent investigation on the phase behavior of thermally stable NPs within the polymer matrices (polymer blends and block copolymer), morphologies of nanocomposites induced by NPs, and examples of their applications are also discussed. These approaches may provide useful strategy to employ the NPs for the fabrication of nanocomposites in diverse applications especially where heat treatment are required. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013
Mechanism for retardation of amyloid fibril formation by sugars in Vλ6 protein
Authors: Abe Masahiro , Abe Yoshito , Ohkuri Takatoshi , Mishima Tomonori , Monji Akira , Kanba Shigenobu , Ueda Tadashi 
Published: February 2013

AbstractSugars, which function as osmolytes within cells, retard the amyloid fibril formation of the amyloidosis peptides and proteins. To examine the mechanism of this retardation in detail, we analyzed the effect of sugars (trehalose, sucrose, and glucose) on the polypeptide chains in 3Hmut Wil, which is formed by the mutation of three His residues in Wil mutant as a cause of amyloid light‐chain (AL) amyloidosis, at pH 2, a pH condition under which 3Hmut Wil was almost denatured. Sugars caused the folding of 3Hmut Wil so that its polypeptide chains adopted a native‐like rather than a denatured conformation, as suggested by tryptophan fluorescence, CD spectroscopy, and heteronuclear NMR. Furthermore, these sugars promoted the folding to a native‐like conformation according to the effect of preferential hydration rather than direct interaction. However, the type of sugar had no effect on the elongation of amyloid fibrils. Therefore, it was concluded that sugar affected the thermodynamic stability of 3Hmut Wil but not the elongation of amyloid fibrils.
Protein–protein interactions: General trends in the relationship between binding affinity and interfacial buried surface area
Authors: Chen Jieming , Sawyer Nicholas , Regan Lynne 
Published: February 2013

AbstractProtein–protein interactions play key roles in many cellular processes and their affinities and specificities are finely tuned to the functions they perform. Here, we present a study on the relationship between binding affinity and the size and chemical nature of protein–protein interfaces. Our analysis focuses on heterodimers and includes curated structural and thermodynamic data for 113 complexes. We observe a direct correlation between binding affinity and the amount of surface area buried at the interface. For a given amount of surface area buried, the binding affinity spans four orders of magnitude in terms of the dissociation constant (Kd). Across the entire dataset, we observe no obvious relationship between binding affinity and the chemical composition of the interface. We also calculate the free energy per unit surface area buried, or “surface energy density,” of each heterodimer. For interfacial surface areas between 500 and 2000 Å2, the surface energy density decreases as the buried surface area increases. As the buried surface area increases beyond about 2000 Å2, the surface energy density levels off to a constant value. We believe that these analyses and data will be useful for researchers with an interest in understanding, designing or inhibiting protein–protein interfaces.
AlGaN/AlN quantum dots for UV light emitters
Authors: Himwas C. , Hertog M. den , Donatini F. , Dang Le Si , Rapenne L. , Sarigiannidou E. , Songmuang R. , Monroy E. 
Published: February 2013

AbstractWe report on the growth and properties of two types of AlGaN/AlN nanostructures: Stranski‐Krastanow quantum dots (SK‐QDs) and nanodisks (NDs) created by nanowire heterostructuring. In both cases, the emission wavelength can be tuned in the range of 240‐350 nm at room temperature by varying the flux ratio and the nominal amount of AlGaN in the nanostructures. The efficient carrier confinement in these nanostructures leads to an internal quantum efficiency around 0.5. However, the emission spectra of AlGaN/AlN NDs show broader linewidth than those of SK‐QDs, which is attributed to inhomogeneities in height and in chemical composition. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)