bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of a label‐free biosensor vertically characterized based on a periodic lattice of high aspect ratio SU‐8 nano‐pillars with a simplified 2D theoretical model
Authors: Casquel R. , Holgado M. , Sanza F. J. , Laguna M. F. , Barrios C. A. , López‐Romero D. , Ortega F. J. , Bañuls M. J. , Puchades R. , Maquieira A. 
Published: February 2011

AbstractWe have recently demonstrated a biosensor based on a lattice of SU8 pillars on a 1 μm SiO2/Si wafer by measuring vertically reflectivity as a function of wavelength. The biodetection has been proven with the combination of Bovine Serum Albumin (BSA) protein and its antibody (antiBSA). A BSA layer is attached to the pillars; the biorecognition of antiBSA involves a shift in the reflectivity curve, related with the concentration of antiBSA. A detection limit in the order of 2 ng/ml is achieved for a rhombic lattice of pillars with a lattice parameter (a) of 800 nm, a height (h) of 420 nm and a diameter(d) of 200 nm. These results correlate with calculations using 3D‐finite difference time domain method. A 2D simplified model is proposed, consisting of a multilayer model where the pillars are turned into a 420 nm layer with an effective refractive index obtained by using Beam Propagation Method (BPM) algorithm. Results provided by this model are in good correlation with experimental data, reaching a reduction in time from one day to 15 minutes, giving a fast but accurate tool to optimize the design and maximizing sensitivity, and allows analyzing the influence of different variables (diameter, height and lattice parameter). Sensitivity is obtained for a variety of configurations, reaching a limit of detection under 1 ng/ml. Optimum design is not only chosen because of its sensitivity but also its feasibility, both from fabrication (limited by aspect ratio and proximity of the pillars) and fluidic point of view. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tunable waveguides based on liquid crystal‐infiltrated silicon photonic crystals
Authors: Cos Joaquín , Ferré‐Borrull Josep , Pallarès Josep , Marsal Lluís F. 
Published: February 2011

AbstractA methodology for the study of the practical implementation of tunable waveguides based on Silicon Photonic Crystals with liquid crystal‐infiltrated pores is presented. First, by using the FDTD method, the transmission properties of the waveguide depending on the liquid crystal optical axis orientation are studied. Then by means of the plane wave expansion method and taking into account the anisotropy of the photonic crystal components and considering adequate supercells, the transmission or rejection of the optical beam are explained. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photonic stop bands of two‐dimensional quasi‐random structures based on macroporous silicon
Authors: Rahman Mohammad Mahbubur , Ferré‐Borrull Josep , Pallarès Josep , Marsal Lluis F. 
Published: February 2011

AbstractThe existence of photonic stop bands in macroporous silicon with a quasi‐random structure transferred from nanoporous anodic alumina is studied. The quasi‐random structure consists of a periodic triangular arrangement broken into domains of random orientation and size. By means of Finite‐Difference Time‐Domain simulation, transmittance spectra of the structure are calculated which show that stop bands exist for the TE polarization in the same frequency range it exist for periodic photonic crystals. For TM polarization local minima of the transmittance are predicted by the calculations. A general trend of the transmittance to decrease with increasing frequency is observed. The comparison with the transmittance for random structures shows that such trend is due to incoherent scattering caused by the degree of randomness of the structure (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrically driven intentionally positioned single quantum dot
Authors: Mehta Minisha , Reuter Dirk , Wieck Andreas D. , Michaelis de Vasconcellos Steffen , Zrenner Artur , Meier Cedrik 
Published: February 2011

AbstractUsing a combined all‐ultra‐high‐vacuum process employing lateral patterning with focused ion beams and molecular beam epitaxy, site‐selective growth of single (In,Ga)As quantum dots is achieved. We have embedded such a layer of intentionally positioned quantum dots in the intrinsic region of a p‐i‐n junction so that the quantum dots can be driven electrically. In this contribution, we will present our results on the morphological properties of the ion‐beam modified surface on which the quantum dot nucleation occurs together with a characterization of the electrical and optoelectronic properties. We will demonstrate that a single, individual quantum dot can directly be electrically addressed. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interaction of terahertz radiation with semiconductors
Authors: Koch Stephan W. , Golde Daniel , Kira Mackillo 
Published: February 2011

AbstractThe microscopic theory of the interaction of terahertz radiation with semiconductors is reviewed.The theory is applied to analyze the intersubband terahertz response of optically excited semiconductor quantum wells (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical studies on the transport property of oligosilane with p‐n junction
Authors: Zhang Gui‐Ling , Yuan Hong‐Liang , Zhang Hui , Shang Yan , Sun Miao 
Published: February 2011

AbstractThe electron transport properties of a novel p‐n junction nanowire caused by boron‐doping and phosphorus‐doping are investigated using density functional theory combined with the nonequilibrium Green's functions formalism. A satisfying rectification is observed. This is a reasonable result after the analysis of the molecular‐projected self‐consistent Hamitonian (MPSH) states, transmission spectra, the frontier orbitals, and the dipole moments. In contrast, the undoped chain has no rectification character. In addition, a negative differential resistance behavior is also observed at V = 1.8 ∼ 2.2 V in the doped nanowire and it could be illustrated from the MPSH states and the transmission spectra. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Meaning of the wave function
Authors: Gao Shan 
Published: February 2011

AbstractWe investigate the meaning of the wave function by analyzing the mass and charge density distributions of a quantum system. According to protective measurement, a charged quantum system has effective mass and charge density distributing in space, proportional to the square of the absolute value of its wave function. In a realistic interpretation, the wave function of a quantum system can be taken as a description of either a physical field or the ergodic motion of a particle. The essential difference between a field and the ergodic motion of a particle lies in the property of simultaneity; a field exists throughout space simultaneously, whereas the ergodic motion of a particle exists throughout space in a time‐divided way. If the wave function is a physical field, then the mass and charge density will be distributed in space simultaneously for a charged quantum system, and thus, there will exist gravitational and electrostatic self‐interactions of its wave function. This not only violates the superposition principle of quantum mechanics but also contradicts experimental observations. Thus, the wave function cannot be a description of a physical field but a description of the ergodic motion of a particle. For the later, there is only a localized particle with mass and charge at every instant, and thus, there will not exist any self‐interaction for the wave function. It is further argued that the classical ergodic models, which assume continuous motion of particles, cannot be consistent with quantum mechanics. On the basis of negative result, we suggest that the wave function is a description of the quantum motion of particles, which is random and discontinuous in nature. On this interpretation, the square of the absolute value of the wave function not only gives the probability of the particle being found in certain locations but also gives the objective probability of the particle being there. We show that this new interpretation of the wave function provides a natural realistic alternative to the orthodox interpretation, and its implications for other realistic interpretations of quantum mechanics are also briefly discussed. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Direct MP2 molecular dynamics studies of H atom reaction with CD4 and CH4
Authors: Lu Peng , Kuang Xiao‐Yu , Li Hui‐Fang , Wang Huai‐Qian 
Published: February 2011

AbstractThe mechanism and dynamics of the H + CD4 → CD3 + HD (I) and H + CH4 → CH3 + H2 (II) reactions have been investigated by electronic structure methods. The minimum‐energy path and vibrational frequencies along the intrinsic reaction coordinate are calculated at MP2/cc‐pVDZ level. Energy distributions of the products are also obtained by the direct classical trajectory calculations at the MP2/ cc‐pVDZ level. It is found that most of the available energy appears as product translational energy, and very little of the available energy is partitioned into internal excitation of the HD (H2) product for reaction I (II), which is in agreement with the experimental evidence. The results indicate that the experimental results could be reproduced by the direct MP2 molecular dynamics calculations. The rotational state distributions of the products show the HD (H2) products are formed with lower rotational quantum numbers than the CD3 (CH3) products. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Finite element analysis in adjacent segment degeneration after lumbar fusion
Authors: Yan Jia‐Zhi , Qiu Gui‐Xing , Wu Zhi‐Hong , Wang Xue‐Song , Xing Ze‐Jun 
Published: February 2011

AbstractBackgroundAdjacent segment degeneration (ASD) following lumbar fusion has been well documented in recent years. However, the pathogenesis of ASD is not clear. To investigate this issue, we established a finite element model of segments L2–L5, simulated a single‐segment posterior fixation in L3–L4 and investigated the stress variation and the effects of the instrumented lumbar posterior fixation on adjacent levels.MethodsModels A, B and C of L2–L5 multisegment finite element intact models were established. In model A, segment L3–L4 was not fixed and was without disc degeneration in the adjacent segment (L2–L3, L4–L5); in model B there was posterior pedicle fixation in segment L3–L4 without disc degeneration in the adjacent segment (L2–L3, L4–L5); in model C there was posterior pedicle fixation in segment L3–L4 with a degenerated disc in the adjacent segment (L2–L3, L4–L5). Four levels of axial pressure, 0.3, 0.5, 1.0 and 2.0 MPa, were compared between each model of the stress variation on the discs of the adjacent segment (L2–L3, L4–L5).ResultsThe maximum principal stress mean value of disc L2–L3 under four pressures in model A was determined. The statistical results showed that stress was not significant difference in disc L2–L3 between models A and B, but there was a significant difference in disc L2–L3 between models A and C and a significant difference between each group in disc L4–L5 under four pressure conditions.ConclusionsThe preoperative degeneration of the adjacent segment of the disc is a significant risk factor for ASD. Copyright © 2011 John Wiley & Sons, Ltd.
Assessment of joint symmetry in arthritis
Authors: Cresswell Lynne , Farewell Vern 
Published: February 2011

AbstractWe evaluate three methods for the assessment of symmetry in the joints affected by an arthritic disease. The first two methods, based on published methodology, are limited by their assumptions. We introduce a third method that enables a more comprehensive investigation. In common with previous methods, this method examines tabulations of observed data for evidence of symmetry. Expected values for the table cells are simulated under an assumption of independent joint disease, whilst allowing for differences between patients, and joint locations, in terms of their susceptibility to disease symptoms. Departures of observed from expected values are assessed via a Pearson‐type goodness‐of‐fit test and are examined for consistency with symmetry. We illustrate the three methods using data on the damage accrued in the hand joints of patients registered at the University of Toronto Psoriatic Arthritis clinic. Copyright © 2011 John Wiley & Sons, Ltd.
Modelling the rate of change in a longitudinal study with missing data, adjusting for contact attempts
Authors: Akacha Mouna , Hutton Jane L. 
Published: February 2011

AbstractThe Collaborative Ankle Support Trial (CAST) is a longitudinal trial of treatments for severe ankle sprains in which interest lies in the rate of improvement, the effectiveness of reminders and potentially informative missingness. A model is proposed for continuous longitudinal data with non‐ignorable or informative missingness, taking into account the nature of attempts made to contact initial non‐responders. The model combines a non‐linear mixed model for the outcome model with logistic regression models for the reminder processes. A sensitivity analysis is used to contrast this model with the traditional selection model, where we adjust for missingness by modelling the missingness process.The conclusions that recovery is slower, and less satisfactory with age and more rapid with below knee cast than with a tubular bandage do not alter materially across all models investigated. The results also suggest that phone calls are most effective in retrieving questionnaires. Copyright © 2011 John Wiley & Sons, Ltd.
Generalized method for adaptive randomization in clinical trials
Authors: Russell D. , Hoare Z. S. J. , Whitaker Rh. , Whitaker C. J. , Russell I. T. 
Published: February 2011

AbstractA flexible, generalized method of treatment allocation is proposed. The method uses a set of controlling parameters that enables the generic algorithm to produce a family of possible outcomes ranging from simple randomization to deterministic allocation. The method controls balance at stratum level, stratification level and overall without detriment to the predictability of the method. The paper lists the desirable characteristics of allocation methods and shows that the proposed method fulfils the majority and is easy to use in the clinical context, once the coding has been established. An explanation of the method for 2, 3 and 4 treatment group allocations is given. Simulations demonstrate the flexibility of the method. Copyright © 2011 John Wiley & Sons, Ltd.
Regression‐assisted deconvolution
Authors: McIntyre Julie , Stefanski Leonard A. 
Published: February 2011

AbstractWe present a semi‐parametric deconvolution estimator for the density function of a random variable biX that is measured with error, a common challenge in many epidemiological studies. Traditional deconvolution estimators rely only on assumptions about the distribution of X and the error in its measurement, and ignore information available in auxiliary variables. Our method assumes the availability of a covariate vector statistically related to X by a mean–variance function regression model, where regression errors are normally distributed and independent of the measurement errors. Simulations suggest that the estimator achieves a much lower integrated squared error than the observed‐data kernel density estimator when models are correctly specified and the assumption of normal regression errors is met. We illustrate the method using anthropometric measurements of newborns to estimate the density function of newborn length. Copyright © 2011 John Wiley & Sons, Ltd.
Changing paradigm for knowledge metaphors from dynamics to thermodynamics
Authors: Bratianu Constantin 
Published: February 2011

AbstractThe aim of the paper is to analyse dominant metaphors in knowledge management thinking, show their limitations by analysing their source domains, and then offer a better alternative. It has been demonstrated that metaphors play an important role in defining the concept of knowledge. In knowledge management important ideas incorporated into the SECI model and other extended knowledge dynamics models are based on the metaphors that have their source domain in Newtonian dynamics. These metaphors have limitations coming from some characteristics of the source domain that cannot be mapped onto the target domain, like the conservation law and linearity. The other limitation is that these metaphors hide the fact that knowledge and emotion go together. In order to integrate emotion into the knowledge concept we need a different set of four metaphors that have as a source domain the paradigm of thermodynamics. Copyright © 2011 John Wiley & Sons, Ltd.
Effects of UV weathering and a CeO2‐based coating layer on the mechanical and structural changes of wood/PVC composites
Authors: Pattamasattayasonthi Napat , Chaochanchaikul Kantima , Rosarpitak Vichai , Sombatsompop Narongrit 
Published: February 2011

AbstractComposite samples (WPVCs) of poly(vinyl chloride) (PVC) and wood flour were prepared in the PVC:wood weight ratio of 1:1, and the mechanical and structural changes of the composites were assessed in terms of UV aging time and condensation temperature. Acrylic coating containing cerium dioxide as a UV absorber was used for moderation of the mechanical and structural changes of PVC in the WPVC composites. The experimental results indicated that the tensile and flexural properties of the composites monotonically decreased when the aging time was increased, the effect being more pronounced at high condensation temperatures. It was observed that the polyene and yellowness indexes of the WPVC composites increased with UV aging time. The hydrophilicity of the WPVC was quantified by contact angle results and found to increase with increasing UV aging because of hydrogen bonding between OH groups on the wood surfaces and water molecules. The acrylic coating containing CeO2 proposed in this work was sufficiently effective for maintaining the levels of hydrophilicity and mechanical properties of the WPVC composites. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers
Stabilization of low‐density polyethylene films containing metal stearates as photodegradants
Authors: Focke Walter W. , Mashele R. Puxley , Nhlapo Nontete S. 
Published: February 2011

AbstractThe effect of various stabilizer additives on Low‐Density Polyethylene films with a thickness of ca. 40 μm and containing metal stearates was studied. The films were subjected to accelerated aging in a QUV Weatherometer. The apparatus was fitted with A320 lamps and operated on a dry cycle at 63°C and an irradiance of 0.67 W/m2. A phosphite (Naugard P) and a phosphate (Alkanox 240P) antioxidant provided good stabilization against UV degradation accelerated by transition metal photocatalysts such as cobalt stearate. These compounds outperformed HALS‐based UV stabilizers and a metal deactivator (Irganox MD 1024) at the concentrations tested. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers
Chlorinated poly(vinyl chloride) stabilization by pentaerythritol/calcium‐zinc stearate mixtures: The fate of pentaerythritol
Authors: Liao Xin , He Bobing , Chen Xian 
Published: February 2011

AbstractThe stabilization effect of pentaerythritol (Pe) combined with calcium and zinc stearates (CaSt2/ZnSt2) on chlorinated poly(vinyl chloride) (CPVC) is investigated. Congo red and dynamic thermal stability data indicate that Pe alone has a mild stabilizing effect on the degradation of CPVC. Addition of mixed CaSt2/ZnSt2 to this system leads to a significant improvement in stability. Thermogravimetric studies indicate that premature weight loss, not observed with either Pe alone or with CaSt2/ZnSt2, is observed when the combined Pe/CaSt2/ZnSt2 systems are employed to stabilize CPVC. Fourier transform infrared (FTIR) spectroscopy and electrospray ionization mass spectrometry (ESIMS) both indicate that condensation (oligomerization) and chlorination of Pe occur when Pe and Pe/CaSt2/ZnSt2 systems are employed to stabilize CPVC. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers
Miscibility and thermal and mechanical properties of melt‐mixed poly(lactic acid)/poly(trimethylene terephthalate)/(methyl methacrylate)‐butadiene‐styrene copolymer blends
Authors: Lin San‐Wai , Cheng Yao‐Yi 
Published: February 2011

AbstractThis study examined the miscibility and mechanical properties of melt‐mixed poly(lactic acid) (PLA), poly (trimethylene terephthalate) (PTT), and PLA/PTT blend with 5–10 phr of methyl methacrylate‐butadiene‐styrene copolymer (MBS). The isothermal crystallization kinetics of the PTT blends were analyzed by using the Avrami equation. The Differential Scanning Calorimetry (DSC) and scanning electron microscope results indicated that the miscibility of the PLA/PTT blends was improved by adding 5–10 phr of MBS. Although PLA, with the addition of 10 phr of MBS, had lower tensile strength at yield and higher breaking elongation and impact strength than pure PLA, no improvement in these mechanical properties could be observed in PLA/PTT blends. This result is explained by assuming that the crystallization of PTT at the interface favors the disentanglement of MBS from the PTT domain. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers
Kinetics of water absorption and thermal properties of poly(lactic acid)/organomontmorillonite/poly(ethylene glycol) nanocomposites
Authors: Leu Ying Ying , Chow Wen Shyang 
Published: February 2011

AbstractPoly(lactic acid) (PLA)/organomontmorillonite (OMMT) nanocomposites were prepared by a melt intercalation technique. The effects of OMMT and poly(ethylene glycol) (PEG) on the thermal properties and water absorption behavior of PLA were investigated. The melting temperature and degree of crystallinity were comparable for the PLA and its nanocomposites. The glass transition temperature and crystallization temperature of PLA were decreased by the addition of PEG. X‐ray diffraction results revealed the formation of PLA nanocomposites, as the OMMT was partly intercalated and partly exfoliated. The maximum moisture absorption of PLA was increased in the presence of PEG and the diffusivity of the PLA nanocomposites decreased with increasing concentrations of PEG. However, the activation energy of the nanocomposites increased as the loading of PEG increased. These results indicated that the incorporation of OMMT and PEG enhanced the water‐barrier properties of the PLA. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers
Heat transfer in a micropolar fluid flow past a permeable continuous moving surface
Authors: El‐Kabeir S.M.M. , Rashad A.M. , Gorla R.S.R. 
Published: February 2011

AbstractA boundary layer analysis is presented for the fluid flow and heat transfer characteristics of an incompressible micropolar fluid flowing over a permeable continuous moving surface with uniform surface heat flux conditions. Two cases are considered, one corresponding to a plane surface moving in parallel with a free stream and the other, a surface moving in the opposite direction to the free stream. The resulting system of non‐linear ordinary differential equations is solved numerically using fourth‐order Runge‐Kutta method with shooting techniques. Numerical results are obtained for velocity, angular velocity, and temperature distributions, as well as the friction factor, local Nusselt number and wall couple stress for prescribed values of the velocity ratio parameter, suction/injection parameter, and micropolar parameter. The obtained results are presented graphically and in tabular form and the physical aspects of the problem are discussed for both parallel and reverse moving plates relative to the free stream direction.