bluuebunny/crossref_metadata_2025_split huggingface dataset:
Presurgical planning for tumor resectioning
Authors: Sunaert Stefan 
Published: April 2006

AbstractSince the birth of functional magnetic resonance imaging (fMRI)—a noninvasive tool able to visualize brain function—now 15 years ago, several clinical applications have emerged. fMRI follows from the neurovascular coupling between neuronal electrical activity and cerebrovascular physiology that leads to three effects that can contribute to the fMRI signal: an increase in the blood flow velocity, in the blood volume and in the blood oxygenation level. The latter effect, gave the technique the name blood oxygenation level dependent (BOLD) fMRI. One of the major clinical uses is presurgical fMRI in patients with brain abnormalities. The goals of presurgical fMRI are threefold: 1) assessing the risk of neurological deficit that follows a surgical procedure, 2) selecting patients for invasive intraoperative mapping, and 3) guiding of the surgical procedure itself. These are reviewed here. Unfortunately, randomized trials or outcome studies that definitively show benefits to the final outcome of the patient when applying fMRI presurgically have not been performed. Therefore, fMRI has not yet reached the status of clinical acceptance. The final purpose of this article is to define a roadmap of future research and developments in order to tilt pre‐surgical fMRI to the status of clinical validity and acceptance. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Role of fMRI in the decision‐making process: Epilepsy surgery for children
Authors: Liégeois Frédérique , Cross J. Helen , Gadian David G. , Connelly Alan 
Published: April 2006

AbstractFunctional MRI (fMRI) is increasingly being used to evaluate children and adolescents who are candidates for surgical treatment of intractable epilepsy. It has the advantage of being noninvasive and well tolerated by young people. By identifying important functional regions within the brain, including unpredictable patterns of functional reorganization, it can aid in surgical decision‐making. Here we illustrate this using a number of case studies from the pediatric epilepsy surgery program at our institution. We describe how fMRI, used in conjunction with conventional investigative methods such as neuropsychological assessment, MRI, and electrophysiology, can 1) help to improve functional outcome by enabling resective surgery that spares functional cortex, 2) guide surgical intervention by revealing when reorganization of function has occurred, and 3) show when abnormal cortex is also functionally active, and hence that surgery may not be the best option. Altogether, these roles have reduced the need for invasive procedures that can be both risky and distressing for young people with epilepsy. In our experience, fMRI has significantly contributed to the decision‐making process, and improved the counseling and management of young people with intractable epilepsy. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Role of functional imaging in neurological disorders
Authors: Weiller Cornelius , May Arne , Sach Miriam , Buhmann Carsten , Rijntjes Michel 
Published: April 2006

AbstractNeuroimaging in recent years has greatly contributed to our understanding of a wide range of aspects related to central neurological diseases. These include the classification and localization of disease, such as in headache; the understanding of pathology, such as in Parkinson's disease (PD); the mechanisms of reorganization, such as in stroke and multiple sclerosis (MS); and the subclinical progress of disease, such as in amyotrophic lateral sclerosis (ALS). Apart from presurgical mapping, however, the clinical applications so far are limited. Nevertheless, functional imaging does enable the formulation of neurobiological hypotheses that can be tested clinically, and thus is well suited for testing classic clinical hypotheses about how the brain works. Understanding the mechanisms and sites of pathology, such as has been achieved in cluster headaches, facilitates the development of new therapeutic strategies. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Self‐Expansion Behavior of Silk Fibroin Film
Authors: Kawahara Yutaka , Furukawa Keiko , Yamamoto Takeshi 
Published: April 2006

AbstractSummary: Silk fibroin cast film was prepared using a ternary solvent system of CaCl2/CH3CH2OH/H2O (1/2/8 in mole ratio). A drying temperature at casting influenced crystal structure of fibroin. When a drying temperature was set lower than 9 °C, the cast film became amorphous. When a drying temperature was set higher than 40 °C, a fibroin film of silk‐II structure was obtained. In order to produce a fibroin film of silk‐I structure, a preferable temperature range was from 20 to 26 °C. The crystal transformation from random coil structure into silk‐I could be made through exposure of an amorphous film to water vapor. As for the crystal transformation from silk‐I into silk‐II, the treatment with a glycerin solution was effective. In the course of the treatment a film showed self‐thinning and self‐expanding. The expansion ratio exceeded 40% at maximum. The film produced accompanying self‐expansion was ductile in nature.The apparent self‐expansion percentage as a function of initial thickness of the film. The ductility of the film was classified into four stages from the observation of recovery behavior after folding: •, very soft; ♦, soft; ▪, middle; ▴, hard (see Figure 5).imageThe apparent self‐expansion percentage as a function of initial thickness of the film. The ductility of the film was classified into four stages from the observation of recovery behavior after folding: •, very soft; ♦, soft; ▪, middle; ▴, hard (see Figure 5).
Gelation Inside Block Copolymer Aggregates and Organic/Inorganic Nanohybrids
Authors: Chen Yongming , Du Jianzhong , Xiong Ming , Zhang Ke , Zhu Hui 
Published: April 2006

AbstractSummary:Like in many other cases, block copolymers bearing alkoxysilyl groups in one segment self‐assemble into aggregates. However, they may allow one to study the sol‐gel reaction by making use of the gelable groups located in the domains of the aggregates, therefore, the gelation process can be made in a selected domain of the nanoscale. As a result, the organic nanostructure is transformed into an organic/inorganic hybrid. The process of using covalently grafted alkoxysilane groups along the block copolymer precursors is applicable not only to the aggregates formed in solution, but also to the other forms of aggregates in melts, thin films, and interfaces. In this feature article, this emerging field is introduced, mainly focusing on the gelation that occurs inside the preformed block copolymer aggregates in solution. The morphologically fixed hybrid nanoparticles, such as spheres, hollow particles, and complex hollow particles, are presented and discussed. This technology has great potentials in the fields of nanomaterials and nanotechnologies, since various organic/inorganic hybrid nanoparticles and nanostructures can be effectively generated using this process.Gelation in preformed block‐copolymer aggregates generates controlled structures.magnified imageGelation in preformed block‐copolymer aggregates generates controlled structures.
Fiber‐reinforced polymer bars embedded in a resin concrete: Study of both materials and their bond behavior
Authors: San‐José J. Tomás , Manso Juan M. 
Published: April 2006

AbstractThe study aims to analyze resin concrete (RC) bond behavior based on an isophthalic polyester resin, reinforced with nonmetallic rebars and is formed by pultruded glass fiber‐reinforced polymer (GFRP). The material is described at micro‐ and macrolevel by presenting the key physical and mechanical properties using different experimental techniques such as Hg porosimetry, scanning electron microscopy, and mechanical testing. Furthermore, a full description of GFRP bars is presented with regard to evaluation of its structural expectancies, embedded in the RC matrix. Given the closed porosity obtained in RC, its microstructure continuity, and organic nature of the binder, this material is highly protected against atmospheric conditions, corrosion and chemical attacks, requiring less cover for tensile reinforcing steel than Portland cement concrete. This research work concludes how the structural compatibility between RC and GFRP is obtained in monotonic bonding tests, providing greater adherence values than those of traditional reinforced concrete. Polym. Compos. 27:315–322, 2006. © 2006 Society of Plastics Engineers
A heuristic approach of calculating spray water flux needed to avert fire‐induced runaway reactions
Authors: Das Dilip K. 
Published: April 2006

AbstractIn general all reactions have some heat effects. When the ability of the equipment to remove the heat is exceeded by the heat generated by a reaction, a hazardous situation called a runaway reaction may take place.Sometimes the exothermicity of runaway reactions is so high that the size of an emergency vent becomes impractical to install. A water spray system can sometimes be used to avert a fire‐induced runaway reaction.Because the water spray system has a finite activation time, insulation helps to prolong the time required to reach the decomposition temperature.This article concludes that the required water flux to avert the fire‐induced runaway reaction may be conservatively estimated by adding the water flux necessary to maintain an unbroken water film on the external surface of the equipment and the water flux necessary to absorb the fire heat after allowing for the splash loss and the in‐flight loss.When adequate spray water is used, the metal temperature of the insulation jacket cannot theoretically exceed the boiling point of water thereby ensuring the avoidance of fire‐induced runaway reactions whose adjusted onset decomposition temperature exceeds 100 ° C. Fire‐induced runaway reactions with lower onset temperature can also be avoided depending on the initial temperature of the contents, mass of the contents and equipment, insulation thickness, and fire duration, for example, but a detailed calculation including dynamic simulation is necessary and the burden of proof lies with the designer.The reliability of the spray water system must be maintained high to include its credit as an environmental factor defined according to NFPA 30 to avoid the fire‐induced runaway reaction as a scenario. Although API RP 521 does not allow any credit for sprinkler water, it allows credit, unlike NFPA 30, for insulation thickness and thus a runaway reaction can be avoided by using insulation alone according to API RP 521. © 2006 American Institute of Chemical Engineers Process Saf Prog, 2006
Electrical properties of individual and small ensembles of InAs/InP nanostructures
Authors: Vicaro K. O. , Gutiérrez H. R. , Bortoleto J. R. R. , Nieto L. , Zuben A. A. G. von , Seabra A. C. , Schulz P. A. , Cotta M. A. 
Published: April 2006

AbstractWe investigate electrical properties of InAs/InP semiconductor nanostructures by conductive atomic force microscopy (C‐AFM) and current measurements at low temperatures in processed devices. Different conductances and threshold voltages for current onset were observed for each type of nanostructure. In particular, the extremity of the wire could be compared to a dot with similar dimensions. The processed devices were used in order to access the in‐plane conductance of an assembly of a reduced number of nanostructures. Here, fluctuations on I –V curves at low temperatures (<40 K) were observed. At these low temperatures and for a suitable range of applied voltages, random telegraph noise (RTN) in the current was observed for devices with dots. These fluctuations can be associated to electrons trapped in dots, as suggested by numerical simulations. A crossover from a semiconductor‐like to a metallic transport behavior is also observed for similar parameters. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Error analysis of boundary condition approximations in the modeling of coaxially‐gated carbon nanotube field‐effect transistors
Authors: McGuire Dylan L. , Pulfrey David L. 
Published: April 2006

AbstractIn the modeling of carbon nanotube field‐effect transistors, non‐physical boundary conditions are often employed at the borders of the simulation space. This paper investigates the consequences of imposing these boundary conditions on common geometries, and proposes solutions which reduce the error without compromising simulation efficiency. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of MBE growth conditions on the surface morphology of Al(Ga)As nanowhiskers
Authors: Tonkikh A. A. , Cirlin G. E. , Dubrovskii V. G. , Sibirev N. V. , Soshnikov I. P. , Samsonenko Yu. B. , Polyakov N. K. , Ustinov V. M. 
Published: April 2006

AbstractThe structural properties of GaAs and AlGaAs nanowhiskers (NWs) grown by molecular beam epitaxy (MBE) on a GaAs substrate surfaces of different crystallographic orientations are investigated. Under optimal growth conditions, the aspect ratio of MBE grown GaAs NWs is higher than 100. The maximum length of NWs is several times (up to 10) larger than the effective thickness of deposited GaAs. A kinetic model of the diffusion‐induced NW growth is used to predict the dependence of NW length on the technologically controlled MBE growth conditions. The obtained results demonstrate that the NW growth in our experiments is mainly controlled by the adatom diffusion towards their tip rather than by the conventional adsorption controlled vapor–liquid–solid mechanism. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparative study of GaAs‐based 1.5 micron‐range InAs/InGaAs and InAs/InAlAs self‐assembled quantum dots
Authors: Gladyshev A. G. , Kryzhanovskaya N. V. , Nadtochy A. M. , Semenova E. S. , Zhukov A. E. , Vasil'ev A. P. , Mikhrin V. S. , Musikhin Yu. G. , Maximov M. V. , Ledentsov N. N. , Ustinov V. M. 
Published: April 2006

AbstractOptical properties of self‐organized QDs grown on thick metamorphic InGaAs layers with different In composition are studied. The dots are formed by an overgrowth of original InAs islands with thin InGaAs or InAlAs layers. Room temperature photoluminescence at 1.55 µm is demonstrated for the sample with 27% In composition in the matrix. The overgrowth with InAlAs layers permits to eliminate the wetting layer states and increase energy separation between QD ground and excited states. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic field influence on nanocrystallization process of FeCoSiBCuNb alloys
Authors: Marín Pilar , López Miguel , Ruiz‐González Luisa , Cortés Gil Raquel , González‐Calbet Jose María , Hernando Antonio 
Published: April 2006

AbstractWe report the influence of magnetic field in the first stages of nanocrystallization process of FeCoSiBCuNb alloys. Amorphous ribbons have been annealed under longitudinal magnetic field. Depending on annealing temperature and magnetic field intensity, we observe the formation of different microstructures. In particular, when annealing at a temperature corresponding to the first stages of nanocrystallization process in the presence of magnetic field, an alignment of grains associated to grain growth related with a decrease of amorphous percentage has been obtained for certain intensities of applied magnetic field. Sample microstructure has been observed by means of TEM and the influence of microstructure in magnetic behaviour has been analysed by means of magnetization and coercivity field evolution with measuring temperature. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carbon nanotubes and nucleic acids: tools and targets
Authors: Onoa Bibiana , Zheng Ming , Dresselhaus Mildred S. , Diner Bruce A. 
Published: April 2006

AbstractNucleic acids are playing an important role in the rapid development of nanotechnologies. Our Editor's Choice [1] discusses the use of nucleic acids to disperse and sort single walled carbon nanotubes (SWNTs). The cover picture shows a two‐dimensional photoluminescence (PL) spectrum of highly purified (6,5) SWNT:DNA hybrids. The fine resolution of the PL peaks displays photo‐excited intermediates in a range of energies between ES22 and ES11 transitions revealing for the first time specific phonon‐assisted optical absorption and energy relaxation mechanisms.The first author, Bibiana Onoa, has been working on carbon nanotubes and nucleic acids in the molecular electronics group of Dupont Central Research and Development. Her current research focuses on the development of nanotechnologies that allow fast and economical detection of pathogens.This special issue of physica status solidi (a) presents representative contributions and main topics on “Trends in Nanotechnology” from the TNT2005 International Conference in Oviedo (Spain).
Displacement of inviscid fluid by a sphere moving away from a wall
Authors: Eames I. , Hunt J. C. R. , Belcher S. E. 
Published: April 2006

We develop a theoretical analysis of the displacement of inviscid fluid particles and material surfaces caused by the unsteady flow around a solid body that is moving away from a wall. The body starts at position hs from the wall, and the material surface is initially parallel to the wall and at distance hL from it. A volume of fluid Df+ is displaced away from the wall and a volume Df- towards the wall. Df+ and Df- are found to be sensitive to the ratio hL/hs. The results of our specific calculations for a sphere can be extended in general to other shapes of bodies.When the sphere moves perpendicular to the wall the fluid displacement and drift volume Df+ are calculated numerically by computing the flow around the sphere. These numerical results are compared with analytical expressions calculated by approximating the flow around the sphere as a dipole moving away from the wall. The two methods agree well because displacement is an integrated effect of the fluid flow and the largest contribution to displacement is produced when the sphere is more than two radii away from the wall, i.e. when the dipole approximation adequately describes the flow. Analytic expressions for fluid displacement are used to calculate Df+ when the sphere moves at an acute angle α away from the wall.In general the presence of the wall reduces the volume displaced forward and this effect is still significant when the sphere starts 100 radii from the wall. A sphere travelling perpendicular to the wall, α = 0, displaces forward a volume Df+(0) = 4πa3hL/33/2hS when the marked surface starts downstream, or behind the sphere, and displaces a volume Df+(0) ∼ 2πa3/3 forward when it is marked upstream or in front of the body. A sphere travelling at an acute angle away from the wall displaces a volume Df+(α) ∼ Df+(0) cos α forward when the surface starts downstream of the sphere. When the marked surface is initially upstream of the sphere, there are two separate regions displaced forward and a simple cosine dependence on α is not found.These results can all be generalized to calculate material surfaces when the sphere moves at variable speed, displacements no longer being expressed in terms of time, but in relation to the distance travelled by the sphere.
The linear stability of mixed convection in a vertical channel flow
Authors: Chen Yen-Cho , Chung J. N. 
Published: April 2006

In this study, the linear stability of mixed-convection flow in a vertical channel is investigated for both buoyancy-assisted and -opposed conditions. The disturbance momentum and energy equations were solved by the Galerkin method. In addition to the case with a zero heat flux perturbation boundary condition, we also examined the zero temperature perturbation boundary condition. In general, the mixed-convection flow is strongly destabilized by the heat transfer and therefore the fully developed heated flow is very unstable and very difficult to maintain in nature. For buoyancy-assisted flow, the two-dimensional disturbances dominate, while for buoyancy-opposed flow, the Rayleigh–Taylor instability prevails for zero heat flux perturbation boundary condition, and for the zero temperature perturbation on the boundaries the two-dimensional disturbances dominate except at lower Reynolds numbers where the Rayleigh–Taylor instability dominates again. The instability characteristics of buoyancy-assisted flow are found to be strongly dependent on the Prandtl number whereas the Prandtl number is a weak parameter for buoyancy-opposed flow. Also the least-stable disturbances are nearly one-dimensional for liquids and heavy oils at high Reynolds numbers in buoyancy-assisted flows.From an energy budget analysis, we found that the thermal–buoyant instability is the dominant type for buoyancy-assisted flow. In buoyancy-opposed flow, under the zero temperature perturbation boundary condition the Rayleigh–Taylor instability dominates for low-Reynolds-number flow and then the thermal–shear instability takes over for the higher Reynolds numbers whereas the Rayleigh–Taylor instability dominates solely for the zero heat flux perturbation boundary condition. It is found that the instability characteristics for some cases of channel flow in this study are significantly different from previous results for heated annulus and pipe flows. Based on the distinctly different wave speed characteristics and disturbance amplification rates, we offer some suggestions regarding the totally different laminar–turbulent transition patterns for buoyancy-assisted and -opposed flows.
Eulerian and Lagrangian scaling properties of randomly advected vortex tubes
Authors: Malik N. A. , Vassilicos J. C. 
Published: April 2006

We investigate the Eulerian and Lagrangian spectral scaling properties of vortex tubes, and the consistency of these properties with Tennekes’ (1975) statistical advection analysis and universal equilibrium arguments. We consider three different vortex tubes with power-law wavenumber spectra: a Burgers vortex tube, an inviscid Lundgren single spiral vortex sheet, and a vortex tube solution of the Euler equation. While the Burgers vortex is a steady solution of the Navier–Stokes equation, the other two are unsteady solutions of, respectively, the Navier–Stokes and the Euler equations. In our numerical experiments we study the vortex tubes by subjecting each of them to external ‘large-scale’ sinusoidal advection of characteristic frequency f and length scale ρ.Not only do we find that the Eulerian frequency spectrum ϕE(ω) can be derived from the wavenumber spectrum E(k) using the simple Tennekes advection relation ω ∼ k for all finite advection frequencies f when the vortex is steady, but also when the vortex is unsteady, and in the Lundgren case even when f = 0 owing to the self-advection of the Lundgren vortex by its own differential rotation.An analytical calculation using the method of stationary phases for f = 0 shows that for large enough Reynolds numbers the combination of strain with differential rotation implies that ϕL(ω) ∼ ω−2+Const for large values of ω. We verify numerically that ϕL(ω) does not change when f ≠ 0. With the Burgers vortex tube we are in a position to investigate the spectral broadening of the Eulerian frequency spectrum with respect to the Lagrangian frequency spectrum. A spectral broadening does exist but is different from the spectral broadening predicted by Tennekes (1975).