bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation of cyclic strain parameters regulates development of elastic modulus in fibroblast/substrate constructs
Authors: Joshi Sagar D. , Webb Ken
Published: March 2008

Dynamic mechanical culture systems are a widely studied approach for improving the functional mechanical properties of tissue engineering constructs intended for loading‐bearing orthopedic applications such as tendon/ligament reconstruction. The design of effective mechanical stimulation regimes requires a fundamental understanding of the effects of cyclic strain parameters on the resulting construct properties. Toward this end, these studies employed a modular cyclic strain bioreactor system and fibroblast‐seeded, porous polyurethane substrates to systematically investigate the effect of varying cyclic strain amplitude, rate, frequency, and daily cycle number on construct mechanical properties. Significant differences were observed in response to variation of all four loading parameters tested. In general, the highest values of elastic modulus within each experimental group were observed at low to intermediate values of the experimental variables tested, corresponding to the low to subphysiological range (2.5% strain amplitude, 25%/s strain rate, 0.1–0.5 Hz frequency, and 7,200–28,800 cycles/day). These studies demonstrate that fibroblasts are sensitive and responsive to multiple characteristics of their mechanical environment, and suggest that systematic optimization of dynamic culture conditions may be useful for the acceleration of construct maturation and mechanical function. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1105–1113, 2008
The stationary set splitting game
Authors: Larson Paul B. , Shelah Saharon
Published: March 2008

The stationary set splitting game is a game of perfect information of length ω1 between two players, unsplit and split, in which unsplit chooses stationarily many countable ordinals and split tries to continuously divide them into two stationary pieces. We show that it is possible in ZFC to force a winning strategy for either player, or for neither. This gives a new counterexample to Σ22 maximality with a predicate for the nonstationary ideal on ω1, and an example of a consistently undetermined game of length ω1 with payoff de.nable in the second‐order monadic logic of order. We also show that the determinacy of the game is consistent with Martin's Axiom but not Martin's Maximum. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The potential of sphingomyelin as a chemopreventive agent in AOM‐induced colon cancer model: wild‐type and p53+/– mice
Authors: Hu Ying , Le Leu Richard K. , Belobrajdic Damien , Young Graeme P.
Published: March 2008

A protective effect of sphingolipids on colorectal cancer (CRC) has been reported in certain mouse strains. It is unknown if sphingolipids are protective in a p53 deficiency mouse model of CRC. This study investigated the effect of sphingomyelin (SM) on intestinal sphingomyelinase (SMase) activity, colonic epithelial biology and azoxymethane (AOM)‐induced CRC. Groups of wild‐type (C57BL/6J) and p53+/– mice were fed 0.1% SM diet for 4 wk, administered a single AOM injection and then killed 6 h later to measure apoptosis and proliferation. Separately, both mouse types were fed 0.05% SM diet, administered three AOM injections and killed 33–38 wk later to measure tumour formation. SM significantly increased SMase activity and reduced proliferation (p < 0.05) in wild‐type and p53+/– mice. SM did not regulate baseline apoptosis, apoptotic response to AOM or apoptosis in tumours, nor did it restore defective apoptosis in p53+/– mice. There was a nonsignificant trend to reduced tumour incidence with SM in wild‐type (p = 0.15) and p53+/– (p = 0.12) mice. In conclusion, while increasing intestinal SMase activity and suppressing proliferation, SM did not promote any form of apoptosis and failed to achieve significant protection in these mice. Further investigation to understand the variable effect of SM in preventing CRC is warranted.
NMR study of the gelation of a designed gelator
Authors: Brand Torsten , Nolis Pau , Richter Sven , Berger Stefan
Published: March 2008

The gelation of a designed gelator was investigated by different NMR methods, which showed a clear thermal hysteresis. Two very simple approaches for the NMR determination of the gelation point are suggested. One involves the observation of the NMR integral, and the other records the ratio of the diffusion coefficients between the gelator and the solvent. Differential behavior of the gelator protons are interpreted as a hint that a part of the gelator molecule might still be flexible as in the dissolved state. Copyright © 2008 John Wiley & Sons, Ltd.
Error correction and convex programming
Authors: Candès Emmanuel , Randall Paige
Published: March 2008

This article discusses a recently proposed error correction method involving convex optimization [1]. From an encoded and corrupted real‐valued message, a receiver would like to determine the original message. A few entries of the encoded message are corrupted arbitrarily (which we call gross errors) and all the entries of the encoded message are corrupted slightly. We show that it is possible to recover the message with nearly the same accuracy as in the setting where no gross errors occur. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experiments on the transition to three‐dimensional flow structures in two‐sided lid‐driven cavities
Authors: Siegmann‐Hegerfeld T. , Albensoeder S. , Kuhlmann H. C.
Published: March 2008

Flow instabilities in two‐sided lid‐driven cavities are studied experimentally. The transition of the nearly two‐dimensional flow to steady or time‐dependent three‐dimensional flow structures is investigated for one‐sided, for parallel, and for antiparallel motion of the driving walls and for two aspect ratios, Γ = 0.76 and Γ = 1. Stability diagrams are obtained by flow visualization. Six different three‐dimensional flow patterns have been characterized, each corresponding to a particular critical mode of a linear‐stability analysis. The structures of the near‐critical flows and the critical curves are in good agreement with the corresponding numerical predictions. In a few cases, however, the critical Reynolds numbers deviate form the numerical results. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical modelling of shear‐thinning non‐Newtonian flow in compliant vessels
Authors: Zaušková Anna , Lukáčová‐Medvid'ová Mária
Published: March 2008

We present recent results on numerical modelling of non‐Newtonian flow in two‐dimensional compliant vessels with application in hemodynamics. Two models of the shear‐thinning non‐Newtonian fluids are considered and compared with the Newtonian model. For the structure problem the generalized string equation for radial symmetric tubes is used and extended to a stenosed vessel. A global iterative approach is used to approximate the fluid‐structure interaction. At the end we present numerical experiments for selected non‐Newtonian models, comparisons with the Newtonian model and the hemodynamic wall parameters: the wall shear stress and the oscillatory stress index. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the dynamics of a nonlinear rotor‐floating ring bearing system
Authors: Boyaci Aydin , Seemann Wolfgang , Proppe Carsten
Published: March 2008

Today, in high speed applications the rotors are commonly supported by hydrodynamic journal bearings. One typical configuration of journal bearings incorporated in automotive turbochargers is the floating ring bearing. Rotors supported by floating ring bearings have many advantages, regarding costs and power consumption for example. However, they might become unstable with increasing speed of rotation. At the onset of instability both the perfectly balanced and unbalanced rotor undergo self‐excited vibrations which could cause the mechanical breakdown of the system. The “oil whip”‐phenomenon, very well known from the investigations of the plain journal bearing occurs here in a different form. At the stability limit the rotor begins either oscillating with about the half of the ring speed or the half of the ring speed plus the half of the journal speed depending on the system parameters.

For this reason a rotor‐floating ring bearing model is presented showing the mentioned characteristics. By applying the nonlinear equations of motion the limit cycles of the system are determined and its loss of stability is investigated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Eigenanalysis of multi‐walled carbon nanotubes by using the impulse response
Authors: Claeyssen Julio R. , Tsukazan Teresa , Copetti Rosemaira D. , Vielmo Sandra
Published: March 2008

The van der Waals interaction elastic force is included in the modeling of multi‐walled carbon nanotubes (MWNT) as an Euler‐Bernoulli elastic system. The coupled eigenvalue problem is formulated in terms of a basis generated by a fundamental matrix response. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Change point oriented multiscale analysis using the lifting scheme
Authors: Jansen Maarten
Published: March 2008

We discuss a non‐linear, change point driven multiscale decomposition, known as normal offsets or normal meshes (in 2‐D). Unlike a wavelet transform, the proposed decomposition runs from coarse to fine scales. The coarse‐to‐fine approach can be seen as an adaptive sampler with theoretical and practical benefits in compression. It is, however, also a source of potential stability problems. Stability is crucial in applications as de‐noising, or simultaneous de‐noising and compression. As the normal offset transform is based on the lifting scheme, we investigate lifting steps that both contribute to stability and allow usage in a change point adaptive normal offset scheme. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Discussion on appropriate material parameters for a porous media model of the IVD
Authors: Karajan Nils , Ehlers Wolfgang
Published: March 2008

The determination of the theoretically introduced material parameters is always a big issue, especially in computational biomechanics. In this context it is difficult to obtain the appropriate intervertebral disc (IVD) specimens within 24 h post decease and to perform reliable experiments on them, respectively. A complex test setup is needed for most of the cases and the measured results are very ‘patient specific’. On the other hand, the parameters obtained from literature are often also not reliable, because they are widespread, the experimental setup is not clearly described or was deficient. Moreover, as soft tissues generally exhibit a coupled dissipative behaviour, it is often not possible to measure these effects independently. Hence, the parameters have to be identified by inverse computations, i. e., axial compression, bending or torsion of a whole motion segment. The goal of this contribution is to proceed from an extended biphasic model and a set of suitable material parameters obtained from literature, in order to find the influence of certain parameters on a numerical compression‐bending experiment of a L4‐L5 motion segment. Finally, a comment on how the respective parameters should be determined is given. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling scale‐free neurodynamics using neuropercolation approach
Authors: Kozma Robert , Puljic Marko
Published: March 2008

Critical properties of dynamical models of neural populations are studied. Based on the classical work of Renyi‐Erdos on the evolution of random graphs, a new class of random cellular automata models called neuropercolation has been introduced. We show the emergence of phase transitions in neuropercolation models at critical combination of several control parameters, including the level of external gain and noise, the density of long‐range axonal connections (small‐world phenomenon), and the sparseness of feedback between excitatory and inhibitory neural populations. Noise level and structural properties of the cortical tissue has been used to control the critical exponent, starting from white noise (slope 0) far away from criticality. The results show that scale‐free power spectral density characterizes the dynamics near criticality, where exponent with a power exponent approaching –2. The results are interpreted in the context of recent experimental findings on the dynamics and structure of the cortex. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Gradient second‐order interphase‐layer theory of continuous media with micro‐structures
Authors: Lurie S. , Tuchkova N.
Published: March 2008

In the paper the second‐order theory of the continuous media with conserved dislocations is developed to describe the spectrum of the cohesion and superficial phenomena. The general model of the continuous media proposed in this work is the rigorous theoretical model that allows to analyze the various particular scale effects, e.g., cohesive interactions, surface within the unified continuum description. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bidiagonal decomposition of totally positive Bernstein‐Vandermonde matrices
Authors: Martínez José‐Javier , Marco Ana
Published: March 2008

The class of Bernstein‐Vandermonde matrices (a generalization of Vandermonde matrices arising when the monomial basis is replaced by the Bernstein basis) is considered. A convenient ordering of their rows makes these matrices strictly totally positive. By using results related to total positivity and Neville elimination, an algorithm for computing the bidiagonal decomposition of a Bernstein‐Vandermonde matrix is constructed. The use of explicit expressions for the determinants involved in the process serves to make the algorithm both fast and accurate. One of the applications of our algorithm is the design of fast and accurate algorithms for solving Lagrange interpolation problems when using the Bernstein basis, an approach useful for the field of Computer Aided Geometric Design since it avoids the stability problems involved with basis transformations between the Bernstein and the monomial bases. A different application consists of the use of the bidiagonal decomposition as an intermediate step of the computation of the eigenvalues and the singular value decomposition of a totally positive Bernstein‐Vandermonde matrix. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient, process‐preserving modified Newton's method for solving reactive multicomponent transport problems in porous media
Authors: Prechtel Alecander
Published: March 2008

In the context of hydrogeochemical multicomponent transport problems coupled via reaction rates the fully implicit solution of the (discretized) problem can be computationally expensive, but it avoids the consistency errors inherent in the popular operator splitting approaches which separate transport and reaction operators.

The efficiency of the globally implicit approach is enhanced however by using Newton's method, analysing the reaction network, and modifying the Jacobian to decouple species equations without deteriorating the performance of the Newton iteration. This is possible in the case of slow kinetics and/or small concentrations. A flexible componentwise sparse matrix linear solver can adapt and change the coupling strategy potentially in every iteration.

Numerical results of academical and realistic case studies are presented that demonstrate the potential of the approach. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Morphogenetic lung defects of JSAP1‐deficient embryos proceeds via the disruptions of the normal expressions of cytoskeletal and chaperone proteins
Authors: Ha Hye‐Yeong , Kim Jung‐Bin , Cho Ik‐Hyun , Joo Hyo‐Jin , Kim Kyoung‐Shim , Lee Kang‐Woo , Sunwoo Hongjai , Im Joo‐Young , Lee Ja‐Kyeong , Hong Jang‐Hee , Han Pyung‐Lim
Published: March 2008

Recent studies have shown that JNK/stress‐activated protein kinase‐associated protein 1 (JSAP1)‐deficient mice die from respiratory failure shortly after birth. To understand the underlying mechanism, we investigated the histological appearances and cell type changes in developing jsap1−/− lungs between E12.5 and E18.5. At the light microscopic level, no overt abnormality was detected in jsap1−/− until E16.5. However, alveoli and airway formations that normally occur after E16.5 were poorly advanced in jsap1−/−. Despite these morphological defects, surfactant secreting cells labeled by anti‐SP‐B or anti‐SP‐C were present in normal ranges in jsap1−/− lungs. Smooth muscle α‐actin expressing cells were also developed in jsap1−/− lungs, although actin expression was decreased. The expressions of transcriptional factors, such as, nuclear factor Ib (Nfib), N‐myc, and octamer transcriptional factor 1 (Oct‐1), which play a critical role in lung morphogenesis, were found to be down‐regulated, whereas signal transducer and activator of transcription 3 (Stat3), sonic hedgehog (Shh), and smoothened (Smo) were up‐regulated, in jsap1−/− lungs at E17.5‐E18.5 compared with those in jsap1+/+ lungs. Proteomics analysis of E17.5 lung identified 39 proteins with altered expressions, which included actin, tropomyosin, myosin light chain, vimentin, heat shock protein (Hsp27), and Hsp84. These results suggest that JSAP1 is required for the normal expressions of cytoskeletal and chaperone proteins in the developing lung, and that impaired expressions of these proteins might cause morphogenetic defects observed in jsap1−/− lungs.
Guided protein extraction from formalin‐fixed tissues for quantitative multiplex analysis avoids detrimental effects of histological stains
Authors: Becker Karl‐Friedrich , Schott Christina , Becker Ingrid , Höfler Heinz
Published: March 2008

Formalin fixed and paraffin embedded (FFPE) tissues are the basis for histopathological diagnosis of many diseases around the world. For translational research and routine diagnostics, protein analysis from FFPE tissues is very important. We evaluated the potential influence of six histological stains, including hematoxylin (Mayer and Gill), fast red, light green, methyl blue and toluidine blue, for yield, electrophoretic mobility in 1‐D gels, and immunoreactivity of proteins isolated from formalin‐fixed breast cancer tissues. Proteins extracted from stained FFPE tissues using a recently established technique were compared with proteins obtained from the same tissues but without prior histological staining. Western blot and quantitative protein lysate microarray analysis demonstrated that histological staining can result in decreased protein yield but may not have much influence on immunoreactivity and electrophoretic mobility. Interestingly, not all staining protocols tested are compatible with subsequent protein analysis. The commonly used hematoxylin staining was found to be suitable for multiplexed quantitative protein measurement technologies although protein extraction was less efficient. For best results we suggest a guided protein extraction method, in which an adjacent hematoxylin/eosin‐stained tissue section is used to control dissection of an unstained specimen for subsequent protein extraction and quantification for research and diagnosis.
Proteomic analysis of pericardial effusion: Characteristics of tuberculosis‐related proteins
Authors: Liu Yen‐Wen , Yang Ming‐Hui , Liu Ping‐Yen , Lee Cheng‐Han , Liao Pao‐Chi , Tyan Yu‐Chang
Published: March 2008

The aim of this study has been designed to identify the tuberculosis (TB)‐related proteins in pericardial effusion by proteomic approaches. TB is one of the major infectious diseases causing pericardial effusion. This study details protein profiles in pericardial effusion from three TB patients and three heart failure patients. Pericardial effusions were analyzed using 2‐DE combined with the nano‐HPLC‐ESI‐MS/MS. Eleven protein spots with differential expression in pericardial effusion were identified between the two groups of TB and heart failure patients (the control group). Seven protein spots were upregulated and four were downregulated. The composition of the pericardial effusion proteome may reflect the pathophysiological conditions affecting the progression of tuberculous pericarditis. The proteins in the tuberculous pericardial effusion with differential expression may serve as new and direct indicators of drug treatment. A possible conclusion is indicated that fibrinogen may play an important role for fibrin assembly in tuberculous pericardial effusion.
Temperature dependence of the optical and kinetic properties of photochromic spirooxazine derivatives in sol‐gel thin films
Authors: Alvarez‐Herrero Alberto , Garranzo Daniel , Pardo Rosario , Zayat Marcos , Levy David
Published: March 2008

The photochromic molecules (1,3,3,5,6‐pentamethyl‐spiro[indoline ‐2‐3′‐[quinolino]oxazine]) were embedded in a phenyl functionalized silica layer prepared by the sol‐gel method. The transparent film acquires a profound blue coloration upon irradiation with ultraviolet light (λ=365 nm) showing an absorption peak at 620 nm. The material recovers the colourless state by thermal bleaching or by irradiation with light at the wavelength of the absorption peak (in the visible). The kinetics of the photochromic transitions depends on the chemical environment of the molecule in the matrix (i.e. polarity), the irradiation intensity and the temperature. A particular set of conditions will determine the equilibrium balance, and hence, the optical constants for the specific steady state. The temperature dependence of the optical properties of photochromic thin films was studied using variable angle spectroscopic ellipsometry. The complex refractive index was analyzed from –30 °C to +70 °C, studying the correlation of the results with the change in the kinetics constants of the material. The main conclusion is that at –30 °C no thermal bleaching is observed, while at +70 °C the thermal kinetic constant is high enough to prevent the coloration of the film. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Product decompositions of experimentally determined non‐depolarizing Mueller matrices
Authors: Ossikovski R. , Garcia‐Caurel E. , Martino A. De
Published: March 2008

The practical implementation of a recently proposed decomposition of non‐depolarizing Mueller matrices into a product of basic polarization devices, i.e. retarders and diattenuators, is demonstrated. In particular, the interest of factorizing a non‐depolarizing Mueller matrix into elementary optical components (two wave‐plates and a plane ellipsometric surface) allowing for its straightforward physical interpretation is outlined. The features of the novel decomposition are compared to those of the classic polar decomposition currently in use. Experimental spectroscopic Mueller matrices are factorized using the decomposition and interpreted in terms of meaningful physical parameters. An immediate practical application of the novel product decomposition is identified with the in situ measurement of the ellipsometric angles through birefringent windows. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ellipsometry characterization of bulk acoustic wave filters
Authors: Nolot E. , Lefevre A. , Hilfiker J. N.
Published: March 2008

A complete bulk acoustic wave (BAW) technology was developed to meet the needs of modern wireless communication equipment. Wide spectral range spectroscopic ellipsometry was used to characterize both the thin piezoelectric aluminum nitride film and the acoustic reflector within the tight specifications required by electrical functionality. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multi‐plate misalignment artifacts in rotating‐compensator ellipsometry: Analysis and data treatment
Authors: Marsik P. , Humlicek J.
Published: March 2008

Rotating compensator ellipsometry using multi‐plate retarders can suffer from various artifacts. Our measurements in the range from 1.4 to 6.2 eV revealed spurious oscillations in ellipsometric parameters. We assign these oscillations to the angular misalignment between the individual plates of the retarder. A simple model using Mueller matrix framework is constructed to describe the observed effects and to elucidate the origin of the artifacts. The model is used to predict the impact of the artifacts on the results of signal analysis, and a calibration procedure is presented. Finally, the knowledge of the origin of the artifacts has been successfully used to reduce substantially the spurious oscillations in measured data. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of linear birefringence of a multiple‐order wave plate using a phase‐sensitive ellipsometer
Authors: Wei H. C. , Hsieh C. H. , Tsai C. C. , Yu L. P. , Chou C.
Published: March 2008

A phase‐sensitive interferometric ellipsometer is setup in order to characterize linearly birefringent parameters (no,ne,m) of a multiple‐order wave plate (MWP) precisely where no and ne are refractive indices of ordinary and extraordinary rays respectively while m is the number of the order of interference.

In order to avoid multiple reflections in MWP during the phase retardation measurement at oblique incidence, two tilted phase retardations with respect to the oblique incident angle rotated along x‐axis and y‐axis are measured and then subtracted from each other. In the mean time, the spatial shifting effect of the emerging beams from MWP is reduced too. This results the accuracy of linear birefringence measurement. Finally, a multiple‐order quartz wave plate was tested. The experimental results verify that the phase‐sensitive interferometric ellipsometer is able to precisely measure linear birefringence and the order number of a MWP. In this measurement, the phase stability of the interferometric ellipsometer was 0.3°/hr. It implies the sensitivity on refractive index measurement at δn ∼ 10–6 was achieved in the experiment. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamics of UV degradation of PMPSi in vacuum and in the air using in‐situ ellipsometry
Authors: Zrzavecká O. Fikarová , Nebojsa A. , Navrátil K. , Nešpůrek S. , Humlíček J.
Published: March 2008

We present a comparative study of UV degradation of poly[methyl(phenyl)silane] (PMPSi) thin films on Si substrate in HV and in the air. When exposed to UV light with energies around 3.6 eV, the Si backbone scission occurs. The degradation rate is influenced by the presence of oxygen, which is bonded to the Si atoms following the backbone scission. In our experiments, the samples were placed in an HV chamber and ellipsometric spectra were continuously recorded in the 3.3–5.0 eV range. The combined tungsten (halogen)‐deuterium source ensuring a proper level of light intensity used for both exposition and measurement. During 100 hours exposures at atmospheric pressure, the PMPSi film degraded completely and its optical response did not change further. Degradation of the sample exposed in vacuum (at the pressure of 5 × 10–6 Pa) is slower and stops earlier. Ellipsometric technique allowed us to perform detailed studies of the degradation dynamics. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adsorption of rhodamine 6G at the water‐air interface
Authors: Greef R. , Frey J. G. , Robinson J. , Danos L.
Published: March 2008

We wanted to detect and quantify adsorption of Rhodamine 6G (R6G) at the air/water interface to supplement previous work using second harmonic generation [1–4]. We found that at incidence angles close to the Brewster angle this can be achieved, even at very low bulk concentration. Fitting to a single film model, we found that adsorption can be measured down to very low concentrations of 10–7 M. This is contrasted with the behaviour of other dyes and other solvents. Outside the wavelength range of the dye absorption band the refractive index of the surface approaches that of pure water. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of the optical properties of organic‐inorganic hybrid polymers by IR to Vis‐fUV spectroscopic ellipsometry
Authors: Logothetidis S. , Laskarakis A. , Georgiou D. , Amberg‐Schwab S. , Weber U.
Published: March 2008

Inorganic‐organic hybrid polymers are used as barrier coatings in order to protect flexible electronic devices from the permeation of atmospheric oxygen and water vapour that induce oxidation to the Flexible Electronic Device (FED) organic layers, reducing their operation, efficiency and stability. In this work, Spectroscopic Ellipsometry (SE) in a wide spectral region, from the infrared (IR) (900–4000 cm–1) to the Vis‐far UV (1.5‐6.5 eV) has been implemented in order to investigate the optical properties of different types of hybrid polymers, which are synthesized via the sol–gel technique onto Polyethylene Terephthalate (PET), SiOx/PET and AlOx/PET substrates. The analysis of the measured SE spectra revealed valuable information about the electronic and vibrational response as well as the cross‐linking mechanisms that control the interface and barrier properties of these materials. Finally, the correlation of the optical properties with the synthesis parameters and the barrier response of these materials will significantly contribute towards their optimization in order to be used as high barrier coatings. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A new sub‐nanosecond spectral ellipsometer for shock physics applications
Authors: Seifter A. , Swift D. C.
Published: March 2008

Detecting phase changes in dynamically loaded materials at pressures up into the megabar regime is among the top challenges in shock physics. Probing the electronic band structure by means of spectral ellipsometry is one of the possible solutions to this problem. For this purpose a fast spectral ellipsometer in the spectral range from 500 to 2000 nm is developed currently in the Physics Division of the Los Alamos National Laboratory. This paper discusses some of the most prominent difficulties associated with shock physics experiments, including sample movement, roughening of the sample surface after shock breakout and a change of index of refraction due to compression of transparent anvils often used in this kind of experiments. The layout of the instrument and its main components (light source, detectors and polarization measurement components) will be described as well as simulated spectra in order to get an understanding of the main contributions to measurement uncertainties. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical nanometrology of Au nanoparticles on a multilayer film
Authors: Chang Yia‐Chung , Hsu Shih‐Hsin , Wei Pei‐Kuen , Kim Young Dong
Published: March 2008

Ellipsometric measurements coupled with efficient theoretical modeling are used to determine the size and distribution density of Au nanoparticles on a multilayer film. The rigorous coupled‐wave analysis (RCWA) and finiteelement Green's function method were used to model the polarization‐dependent reflectivity, and the model calculations are in reasonable agreement with the measurements. This demonstrates that the spectroscopic ellipsometry could be a useful optical tool for nondestructive nanometrology. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
41lanthanum‐based dielectric films analyzed by spectroscopic ellipsometry, X‐ray reflectometry and X‐ray photoelectron spectroscopy
Authors: Edon V. , Gaillet M. , Hugon M.C. , Eypert C. , Durand O. , Cardinaud C.
Published: March 2008

Composition and interfacial properties of LaAlO3/Si thick (50 nm) and thin (7 nm) films were accessed by Far Ultra‐Violet Spectroscopic Ellipsometry (FUV‐SE), X‐Ray Reflectometry (XRR) and X‐Ray Photoelectron Spectroscopy (XPS). FUV‐SE correlated to XRR analysis shows that LaAlO3/Si thick and thin films should be modelled by three‐layer stacks using Tauc‐Lorentz dispersion law. Annealing effects of LaAlO3/Si thin films such as increase of interfacial layer thickness and intermixing between high‐κ oxide and Si were demonstrated by FUV‐SE, and confirmed by XRR and XPS measurements. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Decoupling Functionalization from Sensor Array Assembly Using Detachable Cantilevers
Authors: Mcbride Kevin W. , Snow David E. , Walters Stephanie , Jernigan Zack , Weeks Brandon L. , Dallas Tim
Published: March 2008

Cantilevers are useful as sensor devices with high sensitivity and have shown great promise for dense, multianalyte arrays. One of the difficulties has been the fabrication of multianalyte arrays that are capable of the simultaneous detection of a wide range of chemical and biological species. Functionalization procedures for one class of analytes are often incompatible with other classes and cross contamination is a significant concern when ink‐jet deposition processes are used. In this study, we used surface micromachined cantilevers designed and fabricated using Sandia National Laboratories SUMMiT V MEMS process. The cantilevers are fabricated with a base that can be detached from the parent substrate after functionalization and mounted into a daughter array. We have utilized an IBM‐fabricated 8‐cantilever array chip as our daughter substrate due to its compatibility with a Scentris 8‐cantilever readout system. Our initial work demonstrates that this is a feasible procedure for decoupling functionalization from array assembly. SCANNING 30: 000–000, 2008. © 2008 Wiley Periodicals, Inc.
Description of an in situ method to measure the punch wear during blanking
Authors: Monteil G. , Roizard X. , Gréban F. , Makich H.
Published: March 2008

The purpose of this study is to develop a new method in order to measure the punch wear on a real stamping press during blanking. This in situ measuring method has been used for measuring the wear of tungsten carbide punches during blanking of thin copper alloy sheet steels (approximately 1/10 mm). As the quality of the final parts is largely influenced by the dimensions of the punch, the wear of the punch as low as a few micrometers must be avoided and consequently measured.

So the difficulties to measure such a small wear amount on a high speed real industrial process (800 p/min) associated with the small overall dimensions of the punch is a great challenge.

None of the existing measuring techniques (mainly geometrical) can ensure a continuous wear measurement without dismantling the blanking punch. The wear measurement technique developed for this study is the thin layer activation technique. The working area of the punch has been activated by means of a particles beam. The decay of the activity of the punch allows the punch wear to be monitored. Care has been taken to obtain a precise measurement of the punch wear during blanking.

The results of the measurements of punch wear on an industrial stamping press are presented for various working conditions. For example, the influence of the punched material and the amount of lubrication upon the wear kinetics are described. Copyright © 2008 John Wiley & Sons, Ltd.
Conservation prospects for threatened Vietnamese tree species: results from a demographic study
Authors: Chien Pham Duc , Zuidema Pieter A. , Nghia Nguyen Hoang
Published: March 2008

Given that changes in population size are slow, information on future prospects of long‐lived tree species is necessarily obtained from demographic models. We studied six threatened tree species in four Vietnamese protected areas: the broad‐leavedAnnamocarya sinensis,Manglietia fordianaandParashorea chinensis, and the coniferousCalocedrus macrolepis,Dacrydium elatumandPinus kwangtungensis. With data from a 2‐year field study on recruitment, growth and survival, we constructed matrix models for each species. All species showed continuous regeneration, as indicated by annual seedling recruitment and inverse J‐shaped population structures. To evaluate the future prospects of our study species, we calculated three parameters: (1) asymptotic growth rates (λ) from matrix models indicated significant population declines of 2–3%/year for two species; (2) population trajectories for 50–100 years showed slight population declines (0–3%/year) for five species; and (3) the reproductive period required for an adult tree to replace itself was excessive for three of the six species, suggesting that these species presently have insufficient recruitment. Overall agreement of the three parameters was low, showing that reliance on just one parameter is risky. Combining the three parameters we concluded that prospects are good forDacrydiumandParashorea, worrisome forAnnamocarya,ManglietiaandPinus, and intermediate forCalocedrus. We argue that conservation should involve strict protection of (pre‐)adult trees, as their survival is crucial for population maintenance in all species (high elasticity). For species with poor demographic prospects, active intervention is required to improve seedling and tree growth, enrich populations with seedlings from controlled germination, and restore habitat. Finally, our study suggests that these conservation measures apply to long‐lived trees in general, given that their demography is highly similar. Such measures should be taken before populations decline below critical levels, as long‐lived species will respond slowly to management.
Pilot Study of an Exercise Intervention Suitable for Older Heart Failure Patients with Left Ventricular Systolic Dysfunction
Authors: Witham Miles D. , Daykin Anne R. , McMurdo Marion E.T.
Published: March 2008

Background: Most studies of exercise training for heart failure have been conducted on relatively young patients with little comorbidity. Such programmes are unsuitable for the majority of older frail heart failure patients.

Aims: To test the acceptability and tolerability of an outpatient exercise programme in older heart failure patients with comorbid disease.

Methods: 17 patients aged 70 years and over with left ventricular systolic dysfunction attended twice weekly group exercise classes for 12 weeks, focussing on endurance exercise and everyday functional tasks. Outcome measures were proportion of sessions attended; adverse events and reasons for non-attendance; six-minute walk, accelerometry, hospital depression and anxiety score, Guyatt quality of life scale, carer strain and satisfaction scores.

Results: 83% of sessions were attended; 80% of subjects attended at least 80% of allocated sessions. One adverse incident occurred in 324 person-sessions. Encouraging improvements were seen in six minute walk test (+ 19 m, p = 0.14) and in Functional Limitation Profile score (− 82 points, p = 0.02). 50% of informal carers attended at least one session. No increase in carer strain was noted.

Conclusions: Twice-weekly group exercise focussing on aerobic endurance and everyday functional tasks was acceptable and well-tolerated in this patient group.
Toll‐like receptor‐4 deficiency attenuates doxorubicin‐induced cardiomyopathy in mice
Authors: Riad Alexander , Bien Sandra , Gratz Matthias , Escher Felicitas , Heimesaat Markus M. , Bereswill Stefan , Krieg Thomas , Felix Stephan B. , Schultheiss Heinz P. , Kroemer Heyo K. , Tschöpe Carsten
Published: March 2008

Background:

Cardiac inflammation and generation of oxidative stress are known to contribute to doxorubicin (Dox)‐induced cardiomyopathy. Toll‐like receptors (TLRs) are a part of the innate immune system and are involved in cardiac stress reactions. Since TLR4 might play a relevant role in cardiac inflammatory signalling, we investigated whether or not TLR4 is involved in Dox‐induced cardiotoxicity.

Methods and results:

Five days after a single injection of Dox (20 mg/kg; i.p.), left ventricular pressure–volume loops were measured in wild‐type and TLR4‐deficient mice (TLR4−/−) Dox‐treated and control mice. Analyses of possible pathophysiological mechanisms were performed in left ventricular tissue and isolated myocytes, respectively. Dox injection resulted in an impairment of left ventricular function and neurohumoral activation, indexed by increased ET‐1 expression. This was further associated with an increase in cardiac oxidative stress, inflammation and apoptosis, as indicated by an up‐regulation of cardiac lipid peroxidation, TNF‐α expression and enhanced content of TUNEL‐positive cells. In contrast, TLR4−/−Dox mice showed improved left ventricular function with reduced oxidative and inflammatory stress response including reduced cardiac apoptosis. These results were found to be associated with an increase of GATA‐4 expression.

Conclusions:

TLR4 deficiency improves left ventricular function and attenuates pathophysiological key mechanisms in Dox‐induced cardiomyopathy.
Poor outcome in end‐stage heart failure patients with low circulating calcitriol levels
Authors: Zittermann Armin , Schleithoff Stefanie S. , Götting Christian , Dronow Oxana , Fuchs Uwe , Kuhn Joachim , Kleesiek Knut , Tenderich Gero , Koerfer Reiner
Published: March 2008

Background:

Vitamin D receptor knockout mice develop typical signs of congestive heart failure (CHF). In approximately 20% of stable CHF patients, frankly low concentrations of the vitamin D hormone calcitriol are found.

Aims:

We investigated whether serum calcitriol concentrations predict clinical outcome in end‐stage CHF.

Methods and results:

We collected blood samples in 383 end‐stage CHF patients who were on a waiting list for cardiac transplantation. We assessed associations of calcitriol with disease severity and freedom from event (death or cardiac transplantation) during 1‐year follow‐up. In electively listed patients (n=325), 31% had deficient calcitriol levels (<43pmol/l) compared to 47% in urgently/high urgently listed patients (n=58; P<0.001). As determined by multivariable logistic regression, calcitriol was an independent predictor of the listing status ‘urgent/high urgent’ (P<0.001). Calcitriol concentrations were also significantly lower in patients with an event (n=233) compared to those who survived on the waiting list (P<0.001). Cox regression analysis revealed that patients in the highest calcitriol tertile had a hazard ratio (95% CI) for an event of 0.506 (0.334–0.767) compared with patients in the lowest calcitriol tertile (P=0.005), after adjustment for potential confounders.

Conclusion:

Data indicate that low serum calcitriol concentrations are independently associated with poor clinical outcome in end‐stage CHF.
The Short‐Form McGill Pain Questionnaire as an outcome measure: Test–retest reliability and responsiveness to change
Authors: Strand Liv Inger , Ljunggren Anne Elisabeth , Bogen Baard , Ask Tove , Johnsen Tom Backer
Published: March 2008

Abilities of the Short‐Form McGill Pain Questionnaire to assess change have scarcely been addressed in previous studies. The aim of the present study was to examine test–retest reliability, sensitivity to change and responsiveness to clinically important change using a Norwegian version (NSF‐MPQ) in different groups of patients. ICC(1,1) values for test–retest reliability (relative reliability) assessed 1–3 days apart for total, sensory and affective scores were, respectively, 0.75, 0.76 and 0.62 in patients with musculoskeletal pain (n=58), and 0.93, 0.95 and 0.79 in patients with rheumatic pain (n=25). Variability in total scores (absolute reliability) was less in patients with rheumatic pain (within‐subject standard deviation,Sw=2.70) than in patients with musculoskeletal pain (Sw=4.28). Sensitivity to change by standardized response mean (SRM) was mostly large (>0.80) for three patient groups reporting improvement after treatment. More sensitivity to change was demonstrated by the total and sensory scores than by the affective score, and sensitivity of the total score was similarly good to capture improvement as the Visual Analogue Scale (VAS). Indication was provided that mean improvement of groups in NSF‐MPQ total scores should be >5 on the 0–45 scale to demonstrate a clinically important change. Responsiveness to clinically important change by receiver operating characteristic curve analysis was modest, as area under the curve indicating ability to discriminate improved and not improved patients with musculoskeletal pain, was only 0.61. The study indicates mostly satisfactory test–retest reliability and responsiveness values of the NSF‐MPQ, but shows that the measurement properties vary between groups of patients with pain.
Investigating the effects of distracting stimuli on nociceptive behaviour and associated alterations in brain monoamines in rats
Authors: Ford Gemma K. , Moriarty Orla , McGuire Brian E. , Finn David P.
Published: March 2008

Distraction interventions are used clinically to relieve pain. Exposure to distracting stimuli causes withdrawal of attention from the painful stimulus and reduces perceived pain. However, the neurobiological mechanisms mediating distraction‐induced analgesia are poorly understood due, in part, to a paucity of animal studies modelling this phenomenon. The present study investigated the effects of three distracting stimuli on formalin‐evoked nociceptive behaviour and brain tissue monoamine levels in rats. The three distractors were: exposure to a novel environment, exposure to a novel object, and exposure, without contact, to another rat (conspecific). A control group, habituated to the test arena, was also included. Formalin‐evoked nociceptive behaviour was significantly reduced in rats exposed to the novel object or novel arena, but not those exposed to the conspecific, compared with controls. Antinociception resulting from exposure to the novel object was of longer duration than that resulting from exposure to the novel arena. Failure to detect any distractor‐induced effects on plasma corticosterone levels or aversive behaviours suggests that the stimuli used were non‐stressful. HPLC analysis revealed that there was a significant reduction in serotonin and dopamine metabolites in the medial prefrontal cortex in animals exposed to the novel object. These results indicate that exposure to a novel object or arena reduces nociceptive behaviour in rats, effects accompanied by discrete alterations in serotonin and dopamine metabolites in the medial prefrontal cortex.
Enhancement of offset analgesia during sequential testing
Authors: Derbyshire S.W.G. , Osborn J.
Published: March 2008

Interruption of a continuous noxious heat by a relatively greater noxious heat evokes reductions in pain experience when the original noxious heat returns. The reduction is greater than that evoked by continuous delivery of noxious heat. This disproportionate reduction in pain experience, known as offset analgesia, is presumably mediated by a mechanism different to adaptation or habituation. Reduction in pain experience to an equivalent noxious stimulus, however, has also been demonstrated when applying the same stimulus over a number of days. This reduction due to repeated days of stimulation is known as attenuation. In order to distinguish further the mechanisms of offset analgesia and attenuation we applied noxious heat resulting in an experience of low, medium or high pain to the volar forearm of 16 subjects comparing pain intensity ratings for increases and decreases in temperature, repeated over 3days. Offset analgesia was consistently demonstrated but the effects of attenuation were more complex. There was no attenuation effect for the unchanging stimuli delivered across the 3days of testing but attenuation effects enhanced the offset analgesia resulting in a larger offset analgesia effect on days 2 and 3. It is possible that offset analgesia and attenuation are mediated by inter‐related mechanisms. Further studies might investigate whether offset analgesia involves inhibitory structures such as the PAG‐RVM.