bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electromechanical Actuators Based on Graphene and Graphene/Fe3O4 Hybrid Paper
Authors: Liang Jiajie , Huang Yi , Oh Jiyoung , Kozlov Mikhail , Sui Dong , Fang Shaoli , Baughman Ray H. , Ma Yanfeng , Chen Yongsheng 
Published: August 2011

AbstractExceptionally high specific surface area, mechanical strength, electrical conductivity, and a special two‐dimensional structure make graphene a highly promising material for electromechanical actuators. Electromechanical actuators are fabricated using flexible graphene‐based paper prepared via a filtration process, and the stroke of these graphene‐based actuators is directly measured during electrochemical double‐layer charge injection. Actuation strain up to 0.064% was obtained for pristine graphene paper in response to an applied potential of –1 V in 1 M NaCl solution. Double‐layer charge injection in graphene sheets is believed to induce actuation strain through a combination of coulombic and quantum‐chemical‐based expansion. To increase electrochemical‐double‐layer capacitance and actuator performance, Fe3O4 nanoparticles were used to partially prevent graphene sheets from restacking and allow the electrolyte ions to infiltrate the resulting magnetic graphene paper more easily. The magnetic graphene paper exhibits actuation strain as large as 0.1% at –1 V applied potential, which is about 56% higher than that of the pristine graphene paper.
Graphene: Piecing it Together
Authors: Rümmeli Mark H. , Rocha Claudia G. , Ortmann Frank , Ibrahim Imad , Sevincli Haldun , Börrnert Felix , Kunstmann Jens , Bachmatiuk Alicja , Pötschke Markus , Shiraishi Masashi , Meyyappan M. , Büchner Bernd , Roche Stephan , Cuniberti Gianaurelio 
Published: August 2011

AbstractGraphene has a multitude of striking properties that make it an exceedingly attractive material for various applications, many of which will emerge over the next decade. However, one of the most promising applications lie in exploiting its peculiar electronic properties which are governed by its electrons obeying a linear dispersion relation. This leads to the observation of half integer quantum hall effect and the absence of localization. The latter is attractive for graphene‐based field effect transistors. However, if graphene is to be the material for future electronics, then significant hurdles need to be surmounted, namely, it needs to be mass produced in an economically viable manner and be of high crystalline quality with no or virtually no defects or grains boundaries. Moreover, it will need to be processable with atomic precision. Hence, the future of graphene as a material for electronic based devices will depend heavily on our ability to piece graphene together as a single crystal and define its edges with atomic precision. In this progress report, the properties of graphene that make it so attractive as a material for electronics is introduced to the reader. The focus then centers on current synthesis strategies for graphene and their weaknesses in terms of electronics applications are highlighted.
The effects of distal limb segment shortening on locomotor efficiency in sloped terrain: Implications for Neandertal locomotor behavior
Authors: Higgins Ryan W. , Ruff Christopher B. 
Published: August 2011

AbstractPast studies of human locomotor efficiency focused on movement over flat surfaces and concluded that Neandertals were less efficient than modern humans due to a truncated limb morphology, which may have developed to aid thermoregulation in cold climates. However, it is not clear whether this potential locomotor disadvantage would also exist in nonflat terrain. This issue takes on added importance since Neandertals likely spent a significant proportion of their locomotor schedule on sloped, mountainous terrains in the Eurasian landscape. Here a model is developed that determines the relationship between lower limb segment lengths, terrain slope, excursion angle at the hip, and step length. The model is applied to Neandertal and modern human lower limb reconstructions. In addition, for a further independent test that also allows more climate‐terrain cross comparisons, the same model is applied to bovids living in different terrains and climates. Results indicate that: (1) Neandertals, despite exhibiting shorter lower limbs, would have been able to use similar stride frequencies per speed as longer‐limbed modern humans on sloped terrain, due to their lower crural indices; and (2) shortened distal limb segments are characteristic of bovids that inhabit more rugged terrains, regardless of climate. These results suggest that the shortened distal lower limb segments of Neandertals were not a locomotor disadvantage within more rugged environments.Am J Phys Anthropol, 2011. © 2011 Wiley‐Liss, Inc.
Optimization of (Phenylmethylidene)‐hydantoins as Prostate Cancer Migration Inhibitors: SAR‐Directed Design, Synthesis, and Pharmacophore Modeling
Authors: Mudit Mudit , El Sayed Khalid A. 
Published: August 2011

AbstractProstate cancer is one of the most common cancer forms among males of Western countries. Natural products proved to be an unparalleled source of molecular diversity. The 4‐(hydroxyphenylmethylidene)hydantoin (PMH; 1), (5Z)‐5‐(4‐hydroxybenzylidene)imidazolidine‐2,4‐dione, was isolated from the Red Sea sponge Hemimycale arabica, and recently showed junctional complexes stabilization, anti‐invasive, and antimetastatic activities in vitro and in vivo. The related synthetic analogue, (5Z)‐5‐[4‐(ethylsulfanyl)benzylidene]imidazolidine‐2,4‐dione (2), showed several‐fold‐improved in vivo antimetastatic properties against the highly invasive prostate cancer. To further optimize the activity of PMHs, various ligand‐based strategies were used including the extension of the structure, structural simplification, linker extension, and computer‐assisted CoMFA (Comparative Molecular Field Analysis) results. These strategies yielded thirty 2nd‐generation PMHs, designed based on the 1st‐generation PMHs, such as 1 and 2. Wound‐healing assay was selected to evaluate the in vitro anti‐migratory potential of these new PMHs against the PC‐3 cell line. Several active PMHs, including 10, 13, 24, 29, with nearly twelvefold enhancement of activity vs. 2, were identified. Active compounds were then used to build a pharmacophore model using the SYBYL's DIStance COmparison technique (DISCOtech). Active PMHs were also screened for fragment‐based drug likeness using the OSIRIS program, and an overall drug score was also calculated. Interestingly, the overall drug scores of 24 and 29 along with their anti‐migratory activity were significantly greater than those of 1 and 2. In conclusion, PMHs can be the appropriate scaffolds for the urgently needed drug candidates for the control of androgen independent prostate cancer.
Anthracene and Anthraquinone Derivatives from the Stem Bark of Juglans mandshuricaMaxim.
Authors: Lin Hua , Zhang Yu‐Wei , Zheng Li‐Hua , Meng Xiang‐Ying , Bao Yong‐Li , Wu Yin , Yu Chun‐Lei , Huang Yan‐Xin , Li Yu‐Xin 
Published: August 2011

AbstractOne new anthracene derivative, juglanthracenoside A (1), two new anthraquinones, juglanthraquinone A (2) and juglanthraquinone B (3), along with a new naturally occurring anthraquinone, 9,10‐dihydro‐4,8‐dihydroxy‐9,10‐dioxoanthracene‐2‐carboxylic acid (4), have been isolated from the stem bark of Juglans mandshurica. Their structures were established by detailed spectroscopic analysis and comparison of the NMR data with those of related compounds. Compound 1 displayed noticeable antioxidant activity in both 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) free radical‐scavenging assays, while compound 4 showed strong cytotoxicity against HepG2, SGC7901, HCT‐8, and A549 cell lines in vitro.
MRI‐guided vascular access with an active visualization needle
Authors: Saikus Christina E. , Ratnayaka Kanishka , Barbash Israel M. , Colyer Jessica H. , Kocaturk Ozgur , Faranesh Anthony Z. , Lederman Robert J. 
Published: August 2011

AbstractPurpose:To develop an approach to vascular access under magnetic resonance imaging (MRI), as a component of comprehensive MRI‐guided cardiovascular catheterization and intervention.Materials and Methods:We attempted jugular vein access in healthy pigs as a model of “difficult” vascular access. Procedures were performed under real‐time MRI guidance using reduced field of view imaging. We developed an “active” MRI antenna‐needle having an open‐lumen, distinct tip appearance and indicators of depth and trajectory in order to enhance MRI visibility during the procedure. We compared performance of the active needle against an unmodified commercial passively visualized needle, measured by procedure success among operators with different levels of experience.Results:MRI‐guided central vein access was feasible using both the active needle and the unmodified passive needle. The active needle required less time (88 vs. 244 sec, P = 0.022) and fewer needle passes (4.5 vs. 9.1, P = 0.028), irrespective of operator experience.Conclusion:MRI‐guided access to central veins is feasible in our animal model. When image guidance is necessary for vascular access, performing this component under MRI will allow wholly MRI‐guided catheterization procedures that do not require adjunctive imaging facilities such as x‐ray or ultrasound. The active needle design showed enhanced visibility, as expected. These capabilities may permit more complex catheter‐based cardiovascular interventional procedures enabled by enhanced image guidance. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.
Correlation of phase values with CT hounsfield and R2* values in calcified neurocysticercosis
Authors: Roy B. , Verma S. , Awasthi R. , Rathore R.K. , Venkatesan R. , Yoganathan S.A. , Das J.K. Maria , Prasad K.N. , Gupta R.K. 
Published: August 2011

AbstractPurpose:To correlate phase and R2* derived from susceptibility‐weighted magnetic resonance imaging (MRI) with computed tomography‐Hounsfield (CT‐HU) values in calcified neurocysticercosis and to evaluate phase imaging in the assessment of calcified neurocysticercosis.Materials and Methods:Thirty‐five patients with 52 calcified lesions underwent both CT and MRI. Phase and R2* were calculated from multi‐echo 3D‐T2‐star‐weighted‐angiography data. MRI and CT data were coregistered using mutual information. Spearman's correlation was performed between quantitative phase and CT‐HU and R2* values. The Mann–Whitney U‐test was used to see differences between CT‐HU and R2* values from corresponding positive and negative phase regions.Results:The median values of CT‐HU and R2* from regions with positive and negative phase were found to be 142.10 (range: 41.89–491.75) and 68.5/sec (range: 20–110/sec) and 137.30 (range: 30.83–458.88) and 69/sec (range: 0–110/sec), respectively. There was a significant correlation of positive phase values with corresponding CT‐HU and R2* values. In addition, there was a significant correlation of R2* and CT‐HU with negative phase values.Conclusion:We conclude that there is a significant correlation between negative and positive phase with CT‐HU and R2* values, suggesting that the CT hyperdense lesion may have both calcium and other minerals, which can be differentiated using phase imaging. Conventional MRI should include phase imaging to detect calcified neurocysticercosis. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.
Hydrolysis of carboxylate and phosphate esters using monopyridinium oximes in cationic micellar media
Authors: Singh Namrata , Ghosh Kallol K. , Marek Jan , Kuca Kamil 
Published: August 2011

AbstractThe reactions of p‐nitrophenyl acetate (PNPA) with a series of monopyridinium oximes, viz. 2‐PAM (2‐hydroxyiminomethyl‐1‐methylpyridinium iodide), 3‐PAM (3‐hydroxyiminomethyl‐1‐methylpyridinium iodide), and 4‐PAM (4‐hydroxyiminomethyl‐1‐methylpyridinium iodide) have been studied in the presence of cationic surfactants of same hydrophobic chain length (C16) within the concentration range of 0.5–6.0 mM at pH 8.0 under the pseudo‐first‐order condition. The observed rate constant (kobs) increases with increasing surfactant concentration culminating into a maximum, and this has been analyzed in detail following the concepts of micellar catalysis. The structure–activity relationship of the investigated oximes has been discussed, and 2‐PAM was found to be the most reactive among all the three investigated oximes for the cleavage of PNPA. Esterolytic decomposition of p‐nitrophenyldiphenyl phosphate with oximate ions (CHNO−) was followed in cetyltrimethylammonium bromide micelles at pH 9.0, and 4‐PAM was the most reactive oxime for the micellar hydrolysis of phosphate ester. The apparent acid dissociation constants (pKa) of the investigated oximes have been determined spectrophotometrically. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 569–578, 2011
Evaluation of signal formation in local arterial input function measurements of dynamic susceptibility contrast MRI
Authors: Bleeker Egbert J. W. , Webb Andrew G. , van Walderveen Marianne A. A. , van Buchem Mark A. , van Osch Matthias J. P. 
Published: August 2011

AbstractCorrect arterial input function (AIF) measurements in dynamic susceptibility contrast‐MRI are crucial for quantification of the hemodynamic parameters. Often a single global AIF is selected near a large brain‐feeding artery. Alternatively, local AIF measurements aim for voxel‐specific AIFs from smaller arteries. Because local AIFs are measured higher in the arterial‐tree, it is assumed that these will reflect the true input of the microvasculature much better. However, do the measured local AIFs reflect the true concentration‐time curves of small arteries? To answer this question, in vivo data were used to evaluate local AIF candidates selected based on two different types of angiograms. For interpretation purposes, a 3D numerical model that simulated partial‐volume effects in local AIF measurements was created and the simulated local AIFs were compared to the ground truth. The findings are 2‐fold. First, the in vivo data showed that the shape‐characteristics of local AIFs are similar to the shape‐characteristics of gray matter concentration‐time curves. Second, these findings are supported by the simulations showing broadening of the measured local AIFs compared to the ground truth. These findings are suggesting that local AIF measurements do not necessarily reflect the true concentration‐time curve in small arteries. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Automated liver sampling using a gradient dual‐echo Dixon‐based technique
Authors: Bashir Mustafa R. , Dale Brian M. , Merkle Elmar M. , Boll Daniel T. 
Published: August 2011

AbstractMagnetic resonance spectroscopy of the liver requires input from a physicist or physician at the time of acquisition to insure proper voxel selection, while in multiecho chemical shift imaging, numerous regions of interest must be manually selected in order to ensure analysis of a representative portion of the liver parenchyma. A fully automated technique could improve workflow by selecting representative portions of the liver prior to human analysis. Complete volumes from three‐dimensional gradient dual‐echo acquisitions with two‐point Dixon reconstruction acquired at 1.5 and 3 T were analyzed in 100 subjects, using an automated liver sampling algorithm, based on ratio pairs calculated from signal intensity image data as fat‐only/water‐only and log(in‐phase/opposed‐phase) on a voxel‐by‐voxel basis. Using different gridding variations of the algorithm, the average correct liver volume samples ranged from 527 to 733 mL. The average percentage of sample located within the liver ranged from 95.4 to 97.1%, whereas the average incorrect volume selected was 16.5–35.4 mL (2.9–4.6%). Average run time was 19.7–79.0 s. The algorithm consistently selected large samples of the hepatic parenchyma with small amounts of erroneous extrahepatic sampling, and run times were feasible for execution on an MRI system console during exam acquisition. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Automatic segmentation of amyloid plaques in MR images using unsupervised support vector machines
Authors: Iordanescu Gheorghe , Venkatasubramanian Palamadai N. , Wyrwicz Alice M. 
Published: August 2011

AbstractDeposition of the β‐amyloid peptide (Aβ) is an important pathological hallmark of Alzheimer's disease (AD). However, reliable quantification of amyloid plaques in both human and animal brains remains a challenge. We present here a novel automatic plaque segmentation algorithm based on the intrinsic MR signal characteristics of plaques. This algorithm identifies plaque candidates in MR data by using watershed transform, which extracts regions with low intensities completely surrounded by higher intensity neighbors. These candidates are classified as plaque or nonplaque by an unsupervised learning method using features derived from the MR data intensity. The algorithm performance is validated by comparison with histology. We also demonstrate the algorithm's ability to detect age‐related changes in plaque load ex vivo in amyloid precursor protein (APP) transgenic mice that coexpress five familial AD mutations (5xFAD mice). To our knowledge, this study represents the first quantitative method for characterizing amyloid plaques in MRI data. The proposed method can be used to describe the spatiotemporal progression of amyloid deposition, which is necessary for understanding the evolution of plaque pathology in mouse models of Alzheimer's disease and to evaluate the efficacy of emergent amyloid‐targeting therapies in preclinical trials. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Numerical simulation of the effect of interface friction of a bounding structure on shear deformation in a granular soil
Authors: Ebrahimian Babak , Bauer Erich 
Published: August 2011

SUMMARYRecently, the shear behavior of a cohesionless granular strip that is in contact with a very rough surface of a moving bounding structure has been numerically investigated by several authors by using a micropolar hypoplastic continuum model. It was shown that the micropolar boundary conditions assumed along the interface have a strong influence on the deformations within the granular layer. In previous investigations, only interface friction angles for very rough bounding structures were assumed. In contrast, the focus of the present paper is on the influence of the interface roughness on the deformation behavior of the granular strip when the interface friction angle is lower than the peak friction angle of the granular material. In addition to the interface friction angle, particular attention is also paid to the influence of the mean grain diameter, the solid hardness, the initial void ratio, and the vertical stress on the maximum horizontal shear displacement within the granular layer before sliding is started. Copyright © 2011 John Wiley & Sons, Ltd.
Long‐term results in childhood rhabdomyosarcoma: A report from the Italian cooperative study RMS 79
Authors: Bisogno Gianni , Pastore Guido , Perilongo Giorgio , Sotti Guido , Cecchetto Giovanni , Dallorso Sandro , Carli Modesto 
Published: August 2011

AbstractBackgroundThe results obtained by protocols for children with rhabdomyosarcoma (RMS) have improved in recent decades. Survival curves usually reach a plateau 3 years after the diagnosis, suggesting that long‐term survival can be expected, but late events are known to occur. We analyzed the long‐term results of the RMS 79 protocol to investigate the type and impact of such events.ProcedureFrom 1979 to 1987, 163 children with RMS diagnosed at 21 Italian institutions were registered. Each institution was contacted every year to record patients' status after the end of treatment. When patients were lost to follow‐up, their status was checked by inquiring at the Registry Offices of the towns of residence and the cause of death or occurrence of second cancers was investigated by contacting the patients or their family by phone.ResultsOverall, 16 patients had late events, that is, 7 tumor recurrences, 6 second tumors, and 3 deaths due to treatment‐related complications. The overall survival rates dropped from 62.6 at 3 years to 52.8 at 20 years. By multivariate analysis, the characteristics influencing long‐term survival were histology, tumor site and size, and IRS group. Factors predictive of any kind of late event were tumor site and IRS group.ConclusionsMajor late events can significantly affect the long‐term survival of children with RMS. Modern protocols should provide for a much longer follow‐up than is usually considered to confirm the results achieved and enable possible correlations between primary treatment and late events to be investigated. Pediatr Blood Cancer 2012; 58: 872–876. © 2011 Wiley Periodicals, Inc.
On the correlation functions associated with polynomials of the diffusion operator
Authors: Yaremchuk M. , Smith S. 
Published: August 2011

AbstractCorrelation functions (CFs) associated with the inverse background‐error correlations (iBECs) represented by polynomials of the diffusion operator D are obtained analytically for the binomial approximations of the Gaussian BEC and in the general case of a quadratic polynomial of D. The respective analytical expressions for one‐, two‐ and three‐dimensional cases have two tuning parameters, which provide enough freedom in adjusting the CFs' shape to experimental data. The polynomial coefficients of the corresponding iBEC operator are obtained in terms of these tuning parameters and may be useful in the design of the BEC models for variational data assimilation. Published in 2011 by John Wiley & Sons Ltd.
A two‐step watermarking attack using long‐range correlation image restoration
Authors: Taherinia Amir H. , Jamzad Mansour 
Published: August 2011

ABSTRACTThis paper presents an efficient scheme for blind watermark attacking using the concept of matching of the long‐range data. The main idea of the proposed attack is to add plenty of noise to the watermarked image and then try to restore an unwatermarked copy of the noisy image. The aim is to destroy the watermark information without accessing the parameters used during the watermark embedding process. So, it allows our approach to be completely free from any pre‐assumption on the watermarking algorithm or any other parameters that is used during the watermark embedding procedure. Experimental results show the proposed algorithm's superiority over several other traditional watermarking benchmarks such as Stirmark and Optimark. Peak signal‐to‐noise ratio of the watermarked image after applying the proposed attack is more than 45 dB, and the normalized cross‐correlation for the extracted watermark is lower than 0·4, so the watermark is not detectable after our attack. Copyright © 2011 John Wiley & Sons, Ltd.
Nanopatterning of Ferritin Molecules and the Controlled Size Reduction of Their Magnetic Cores
Authors: Martinez Ramsés V. , Chiesa Marco , Garcia Ricardo 
Published: August 2011

AbstractA nanopatterning method to deposit ferritin proteins with nanoscale accuracy over large areas is reported. Selective deposition is driven by the electrostatic interactions existing between the proteins and nanoscale features. Upon deposition, the protein shell can be removed by heating the patterns in an oxygen atmosphere. This leaves exposed the iron oxide core, which can be further reduced in size by plasma‐etching methods. In this way, the initial ferritin molecules, which have a nominal size of 12 nm, are reduced to 2 nm nanoparticles. Magnetic force measurements confirm the magnetic activity of the as‐deposited and etched nanoparticles.