bluuebunny/crossref_metadata_2025 huggingface dataset:
Microwave and Ionic Liquids: Inverse Temperature Dependence of Viscosity in Aqueous Medium of Grafted Copolymers
Authors: Bezdushna Ella , Ritter Helmut
Published: September 2009

We elaborated a route to the thermosensitive polyelectrolyte system composed of 1‐methyl‐3‐vinylimidazolium salt with β‐cyclodextrin complexed counterions and mono‐(meth)acrylic functionalized poly(N‐isopropylacrylamide) as grafted side chains via a three‐step synthetic procedure. The aqueous solution of the polyelectrolyte displays partially inverse thermoresponsive behavior; it exhibits enhancement of shear viscosity up to body temperature. Furthermore, based on classically prepared poly(NIPAAm) bearing terminal amino groups, corresponding (meth‐) acrylamide‐type of macromonomers were easily obtained under microwave conditions.

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Improved signal spoiling in fast radial gradient‐echo imaging: Applied to accurate T1 mapping and flip angle correction
Authors: Lin Wei , Song Hee Kwon
Published: September 2009

In conventional spoiled gradient echo imaging utilizing quadratic radio frequency (RF) spoiling, nonideal signal intensities are often generated, particularly when repetition time is short and/or excitation flip angle (FA) becomes larger. This translates to significant errors in various quantitative applications based on T1‐weighted image intensities. In this work, a novel spoiling scheme is proposed, based on random gradient moments and RF phases. This scheme results in a non‐steady‐state condition, but achieves ideal mean signal intensity. In order to suppress artifacts created by the inter‐TR signal variations and at the same time attain the ideal signal intensity, radial data acquisition is utilized. The proposed method achieves ideal spoiling for a wide range of T1, T2, TR, and FAs. Phantom and in vivo experiments demonstrate improved performance for T1 mapping and FA correction when compared with conventional RF spoiling methods. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Estimation of brain iron concentration in vivo using a linear relationship between regional iron and apparent transverse relaxation rate of the tissue water at 4.7T
Authors: Mitsumori Fumiyuki , Watanabe Hidehiro , Takaya Nobuhiro
Published: September 2009

Maps of the apparent transverse relaxation time (T2†) were collected on a transaxial plane across the basal ganglia in 54 healthy subjects at 4.7T using a multiecho adiabatic spin‐echo (MASE) imaging sequence. We attempted to quantify the nonhemin iron concentration ([Fe]) in various brain regions in vivo based on the linear relationship between the apparent relaxation rate constant (R2† = 1/T2†) and regional [Fe], as demonstrated previously in 12 subjects. The calculated [Fe] in five gray matter (GM) regions agreed well with the previously reported regional iron distribution as well as reproduced its age‐dependent change. In particular, a decrease of iron in the thalamus region in subjects over 30 years of age was demonstrated while an upward trend was shown in other regions. Furthermore, the average R2† in each GM region in subjects over 30 years of age showed a deviation from the regression line with [Fe] in an identical manner to that obtained in the previous 12 subjects. This strongly suggests that there is a systematic regional factor affecting R2†, in addition to iron. Interregional difference in the macromolecular mass fraction (fM) explained this systematic deviation well. When accounting for fM in the analysis, the apparent transverse relaxation rate seems to give a significantly better estimation of regional [Fe]. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Tyrosine polyethylene glycol (PEG)‐micelle magnetic resonance contrast agent for the detection of lipid rich areas in atherosclerotic plaque
Authors: Beilvert Anne , Cormode David P. , Chaubet Frédéric , Briley‐Saebo Karen C. , Mani Venkatesh , Mulder Willem J.M. , Vucic Esad , Toussaint Jean‐François , Letourneur Didier , Fayad Zahi A.
Published: September 2009

Vulnerable or high‐risk atherosclerotic plaques often exhibit large lipid cores and thin fibrous caps that can lead to deadly vascular events when they rupture. In this study, polyethylene glycol (PEG)‐micelles that incorporate a gadolinium diethylenetriamine pentaacetic acid (Gd‐DTPA) amphiphile were used as an MR contrast agent. In an approach inspired by lipoproteins, the micelles were functionalized with tyrosine residues, an aromatic, lipophilic amino acid, to reach the lipid‐rich areas of atherosclerotic plaque in a highly efficient manner. These micelles were applied to apolipoprotein E−/− (ApoE−/−) mice as a model of atherosclerosis. The abdominal aortas of the animals were imaged using T1‐weighted (T1W) high‐resolution MRI at 9.4T before and up to 48 h after the administration of the micelles. PEG‐micelles modified with 15% tyrosine residues yielded a significant enhancement of the abdominal aortic wall at 6 and 24 h postinjection (pi) as compared to unmodified micelles. Fluorescence microscopy on histological sections of the abdominal aorta showed a correlation between lipid‐rich areas and the distribution of the functionalized contrast agent in plaque. Using a simple approach, we demonstrated that lipid‐rich areas in atherosclerotic plaque of ApoE−/− mice can be detected by MRI using Gd‐DTPA micelles. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Sources of hepatic glycogen synthesis during an oral glucose tolerance test: Effect of transaldolase exchange on flux estimates
Authors: Delgado Teresa C. , Silva Claúdia , Fernandes Isabel , Caldeira Madalena , Bastos Margarida , Baptista Carla , Carvalheiro Manuela , Geraldes Carlos F. G. C. , Jones John G.
Published: September 2009

Sources of hepatic glycogen synthesis during an oral glucose tolerance test were evaluated in six healthy subjects by enrichment of a 75‐g glucose load with 6.67% [U‐13C]glucose and 3.33% [U‐2H7]glucose and analysis of plasma glucose and hepatic uridine diphosphate–glucose enrichments (sampled as urinary menthol glucuronide) by 2H and 13C nuclear magnetic resonance. The direct pathway contribution, as estimated from the dilution of [U‐13C]glucose between plasma glucose and glucuronide, was unexpectedly low (36 ± 5%). With [U‐2H7]glucose, direct pathway estimates based on the dilution of position 3 2H‐enrichment between plasma glucose and glucuronide were significantly higher (51 ± 6%, P = 0.05). These differences reflect the exchange of the carbon 4, 5, and 6 moiety of fructose‐6‐phosphate and glyceraldehyde‐3‐phosphate catalyzed by transaldolase. As further evidence of this exchange, 2H‐enrichments in glucuronide positions 4 and 5 were inferior to those of position 3. From the difference in glucuronide positions 5 and 3 enrichments, the fraction of direct pathway carbons that experienced transaldolase exchange was estimated at 21 ± 4%. In conclusion, the direct pathway contributes only half of hepatic glycogen synthesis during an oral glucose tolerance test. Glucose tracers labeled in positions 4, 5, or 6 will give significant underestimates of direct pathway activity because of transaldolase exchange. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
SSFP signal with finite RF pulses
Authors: Bieri Oliver , Scheffler Klaus
Published: September 2009

The theoretical description of steady state free precession (SSFP) sequences is generally well accepted and unquestioned, although it is based on instantaneously acting radiofrequency (RF) pulses. In practice, however, all excitation processes are finite, thereby questioning the overall validity of the common SSFP signal description for use with finite RF pulses. In this paper, finite RF pulse effects on balanced SSFP signal formation are analyzed as a function of the RF time, the pulse repetition time, the flip angle (α) and relaxation times (T1,2). The observed signal modulations from finite RF pulses (compared to infinitesimal ones) can range from only a few percent (for RF time/pulse repetition time ≪ 1, α ≪ 90°, T2/T1 ∼ 1) to over 10% (for RF time/pulse repetition time ≪ 1, α ∼ 90°, T2/T1 ≪ 1) and may even exceed 100% in the limit of RF time/pulse repetition time → 1 (for α ∼ 90°, T2/T1 ≪ 1). As a result, a revision of SSFP signal theory is indicated not only for reasons of completeness but also seems advisable, e.g., for all quantitative SSFP methods. A simple modification for the common balanced SSFP equation is derived that provides an accurate framework for SSFP signal description over a wide variety of practical and physiologic parameters. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
An internal reference model–based PRF temperature mapping method with Cramer‐Rao lower bound noise performance analysis
Authors: Li Cheng , Pan Xinyi , Ying Kui , Zhang Qiang , An Jing , Weng Dehe , Qin Wen , Li Kuncheng
Published: September 2009

The conventional phase difference method for MR thermometry suffers from disturbances caused by the presence of lipid protons, motion‐induced error, and field drift. A signal model is presented with multi‐echo gradient echo (GRE) sequence using a fat signal as an internal reference to overcome these problems. The internal reference signal model is fit to the water and fat signals by the extended Prony algorithm and the Levenberg‐Marquardt algorithm to estimate the chemical shifts between water and fat which contain temperature information. A noise analysis of the signal model was conducted using the Cramer‐Rao lower bound to evaluate the noise performance of various algorithms, the effects of imaging parameters, and the influence of the water:fat signal ratio in a sample on the temperature estimate. Comparison of the calculated temperature map and thermocouple temperature measurements shows that the maximum temperature estimation error is 0.614°C, with a standard deviation of 0.06°C, confirming the feasibility of this model‐based temperature mapping method. The influence of sample water:fat signal ratio on the accuracy of the temperature estimate is evaluated in a water‐fat mixed phantom experiment with an optimal ratio of approximately 0.66:1. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Application of DENSE‐MR‐elastography to the human heart
Authors: Robert Benjamin , Sinkus Ralph , Gennisson Jean‐Luc , Fink Mathias
Published: September 2009

Typically, MR‐elastography (MRE) encodes the propagation of monochromatic acoustic waves in the MR‐phase images via sinusoidal gradients characterized by a detection frequency equal to the frequency of the mechanical vibration. Therefore, the echo time of a conventional MRE sequence is typically longer than the vibration period which is critical for heart tissue exhibiting a short T2. Thus, fast acquisition techniques like the so‐called fractional encoding of harmonic motions were developed for cardiac applications. However, fractional encoding of harmonic motions is limited since it is two orders of magnitude less sensitive to motion than conventional MRE sequences for low‐frequency vibrations. Here, a new sequence is derived from the so‐called displacement encoding with stimulated echoes (DENSE) sequence. This sequence is more sensitive to displacement than fractional encoding of harmonic motions, and its spectral specificity is equivalent to conventional MRE sequences. The theoretical spectral properties of this new motion‐encoding technique are validated in a phantom and excised pork heart specimen. An excellent agreement is found for the measured displacement fields using classic MRE and displacement encoding with stimulated echoes MRE (8% maximum difference). In addition, initial in vivo results on a healthy volunteer clearly show propagating shear waves at 50 Hz. Thus, displacement encoding with stimulated echoes MRE is a promising technique for motion encoding within short T2* materials. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Magnetic resonance elastography: Inversions in bounded media
Authors: Kolipaka Arunark , McGee Kiaran P. , Manduca Armando , Romano Anthony J. , Glaser Kevin J. , Araoz Philip A. , Ehman Richard L.
Published: September 2009

Magnetic resonance elastography is a noninvasive imaging technique capable of quantifying and spatially resolving the shear stiffness of soft tissues by visualization of synchronized mechanical wave displacement fields. However, magnetic resonance elastography inversions generally assume that the measured tissue motion consists primarily of shear waves propagating in a uniform, infinite medium. This assumption is not valid in organs such as the heart, eye, bladder, skin, fascia, bone and spinal cord, in which the shear wavelength approaches the geometric dimensions of the object. The aim of this study was to develop and test mathematical inversion algorithms capable of resolving shear stiffness from displacement maps of flexural waves propagating in bounded media such as beams, plates, and spherical shells, using geometry‐specific equations of motion. Magnetic resonance elastography and finite element modeling of beam, plate, and spherical shell phantoms of various geometries were performed. Mechanical testing of the phantoms agreed with the stiffness values obtained from finite element modeling and magnetic resonance elastography data, and a linear correlation of r2 ≥ 0.99 was observed between the stiffness values obtained using magnetic resonance elastography and finite element modeling data. In conclusion, we have demonstrated new inversion methods for calculating shear stiffness that may be more appropriate for waves propagating in bounded media. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
High spatial and temporal resolution cardiac cine MRI from retrospective reconstruction of data acquired in real time using motion correction and resorting
Authors: Kellman Peter , Chefd'hotel Christophe , Lorenz Christine H. , Mancini Christine , Arai Andrew E. , McVeigh Elliot R.
Published: September 2009

Cine MRI is used for assessing cardiac function and flow and is typically based on a breath‐held, segmented data acquisition. Breath holding is particularly difficult for patients with congestive heart failure or in pediatric cases. Real‐time imaging may be used without breath holding or ECG triggering. However, despite the use of rapid imaging sequences and accelerated parallel imaging, real‐time imaging typically has compromised spatial and temporal resolution compared with gated, segmented breath‐held studies. A new method is proposed that produces a cardiac cine across the full cycle, with both high spatial and temporal resolution from a retrospective reconstruction of data acquired over multiple heartbeats during free breathing. The proposed method was compared with conventional cine images in 10 subjects. The resultant image quality for the proposed method (4.2 ± 0.4) without breath holding or gating was comparable to the conventional cine (4.4 ± 0.5) on a five‐point scale (P = n.s.). Motion‐corrected averaging of real‐time acquired cardiac images provides a means of attaining high‐quality cine images with many of the benefits of real‐time imaging, such as free‐breathing acquisition and tolerance to arrhythmias. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Simplified 13C metabolic modeling for simplified measurements of cerebral TCA cycle rate in vivo
Authors: Valette Julien , Boumezbeur Fawzi , Hantraye Philippe , Lebon Vincent
Published: September 2009

13C NMR spectroscopy is a unique tool to measure the cerebral tricarboxylic acid (TCA) cycle rate in vivo. The measurement relies on metabolic modeling of glutamate C3 and C4 enrichment time courses during a 13C‐glucose intravenous infusion. Usual metabolic models require the plasma glucose and 13C‐glucose time courses as input functions, as well as the knowledge of Michaelis‐Menten kinetics parameters governing passage through the blood‐brain barrier. It is shown in the present work that, when using an infusion protocol yielding a rapidly stable plasma glucose fractional enrichment, metabolic modeling can be simplified in such a manner that this additional information on input function and glucose transport is no longer required, significantly simplifying the measurement of cerebral TCA cycle rate in vivo. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Flat boundaries and their effect on sand testing
Authors: Marketos G. , Bolton Malcolm D.
Published: September 2009

A study of the effect of the use of flat boundaries on the stressing of a sample of an idealized granular material with no applied shear is presented. Discrete element method (DEM) data of 1D compression were analysed and the local strain field inside the sample was investigated as the sample was stressed. A best‐fit strain was seen to best describe the material behaviour free from boundary effects. The individual particle displacements were probed, providing insight into the behaviour of particles adjacent to the boundaries. In addition, the porosity and force distribution inside the sample were observed, allowing for estimates of the width of a boundary region to be made. This region, non‐representative of far‐field material behaviour, will affect the behaviour of a granular sample in DEM or laboratory tests, with local porosity differences leading to a change in the transport properties of the sample, and force distribution changes leading to a bias in the location of grain cracking or crushing events for sufficiently high stress levels. Nevertheless, the largest effect of the boundary region was a severe underestimation of the stiffness of a granular material. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and characterization of temperature‐responsive copolymers based on N‐vinylcaprolactam and their grafting on fibres
Authors: Crespy Daniel , Golosova Anastasia , Makhaeva Elena , Khokhlov Alexei R , Fortunato Giuseppino , Rossi René
Published: September 2009

BACKGROUND: Responsive materials are able to respond reversibly to an environmental stimulus. When the stimulus is temperature in the physiological range, the responsive material is particularly interesting for textile applications. We describe here the synthesis and characterization of reactive temperature‐responsive copolymers and their subsequent grafting on cotton fabrics.

RESULTS: Copolymers of N‐vinylcaprolactam and various reactive monomers were synthesized via free radical polymerization in solution. The copolymers were characterized in terms of chemical structure, molecular weight and temperature‐responsive properties. The copolymer of N‐vinylcaprolactam and methacrylic acid (11 or 22 wt%) and the hydrolysed copolymer of N‐vinylcaprolactam and acryloyl chloride were found to be temperature responsive. They were subsequently grafted on cotton fabrics. The grafting was studied using X‐ray photoelectron spectroscopy and scanning electron microscopy measurements and was found to be effective. Finally, the modified cotton fabrics were found to exhibit temperature‐responsive water regain and water vapour transmission rates.

CONCLUSION: Temperature‐responsive copolymers were synthesized, characterized and successfully grafted on cotton fabrics, yielding responsive fabrics. Such fabrics can hence be used to modulate the skin microclimate under textiles. Copyright © 2009 Society of Chemical Industry
Non‐vacuum methods for formation of Cu(In, Ga)(Se, S)2thin film photovoltaic absorbers
Authors: Hibberd C. J. , Chassaing E. , Liu W. , Mitzi D. B. , Lincot D. , Tiwari A. N.
Published: September 2009

Polycrystalline thin films of copper indium diselenide and its alloys with gallium and sulphur (CIGS) have proven to be suitable for use as absorbers in high‐efficiency solar cells. Record efficiency devices of 20% power conversion efficiency have been produced by co‐evaporation of the elements under high vacuum. However, non‐vacuum methods for absorber deposition promise significantly lower capital expenditure and reduced materials costs, and have been used to produce devices with efficiencies of up to 14%. Such efficiencies are already high enough for commercial up‐scaling to be considered and several companies are now trying to develop products based on non‐vacuum deposited CIGS absorbers. This article will review the wide range of non‐vacuum techniques that have been used to deposit CIGS thin films, highlighting the state of the art and efforts towards commercialization. Copyright © 2009 John Wiley & Sons, Ltd.
Effective Detonation Synthesis of Cubic Boron Nitride
Authors: Gavrilkin Sergei M. , Batsanov Stepan S. , Gordopolov Yury A. , Smirnov Alexander S.
Published: September 2009

Successful realization of detonation‐induced h‐BN→c‐BN phase transition requires that a hydrolysis of BN by water from the detonation products is suppressed. For this two kinds of experiments for synthesis of c‐BN were attempted: using benzo‐trifuroxan (with no water in products) as an explosive, in 80% yield; and using the cast 50% TNT+50% RDX charges containing 5–25 wt.‐% of h‐BN powder in order to expend water from the detonation products by a part of BN, and to realize the phase transition in the rest, in 10% yield.
Influence of the H‐site residue 108 on human glutathione transferase P1‐1 ligand binding: Structure‐thermodynamic relationships and thermal stability
Authors: Quesada‐Soriano Indalecio , Parker Lorien J. , Primavera Alessandra , Casas‐Solvas Juan M. , Vargas‐Berenguel Antonio , Barón Carmen , Morton Craig J. , Paola Mazzetti Anna , Lo Bello Mario , Parker Michael W. , García‐Fuentes Luis
Published: September 2009

The effect of the Y108V mutation of human glutathione S‐transferase P1‐1 (hGST P1‐1) on the binding of the diuretic drug ethacrynic acid (EA) and its glutathione conjugate (EASG) was investigated by calorimetric, spectrofluorimetric, and crystallographic studies. The mutation Tyr 108 → Val resulted in a 3D‐structure very similar to the wild type (wt) enzyme, where both the hydrophobic ligand binding site (H‐site) and glutathione binding site (G‐site) are unchanged except for the mutation itself. However, due to a slight increase in the hydrophobicity of the H‐site, as a consequence of the mutation, an increase in the entropy was observed. The Y108V mutation does not affect the affinity of EASG for the enzyme, which has a higher affinity (Kd ∼ 0.5 μM) when compared with those of the parent compounds, K ∼ 13 μM, K ∼ 25 μM. The EA moiety of the conjugate binds in the H‐site of Y108V mutant in a fashion completely different to those observed in the crystal structures of the EA or EASG wt complex structures. We further demonstrate that the ΔCp values of binding can also be correlated with the potential stacking interactions between ligand and residues located in the binding sites as predicted from crystal structures. Moreover, the mutation does not significantly affect the global stability of the enzyme. Our results demonstrate that calorimetric measurements maybe useful in determining the preference of binding (the binding mode) for a drug to a specific site of the enzyme, even in the absence of structural information.
Recommended management of eczema in older patients
Authors: Sherman Victoria , Creamer Daniel
Published: September 2009

Our series Prescribing in older people gives practical advice for successful management of the special problems faced by this age group. Here, the authors describe the management of eczema in older people. Copyright © 2009 Wiley Interface Ltd
Malaria in children: bite avoidance and prophylaxis
Authors: Gawthrop Mary , Ford Lisa
Published: September 2009

Our series Prescribing in children gives practical advice for successful man‐agement of childhood prob‐lems in general practice. Here, the authors describe the mosquito bite avoidance and malaria prophylaxis options for this age group. Copyright © 2009 Wiley Interface Ltd
Recommended treatment and prevention of osteoporosis
Authors: Bhalla Ashok
Published: September 2009

Our Drug review of osteoporosis opens with details of the available drug treatments, their properties, efficacy and side‐effects, followed by a discussion of the latest NICE guidelines on primary and secondary prevention, an analysis of prescription data and sources of further information. Copyright © 2009 Wiley Interface Ltd
Design and technology considerations for SiC bipolar devices: BJTs, IGBTs, and GTOs
Authors: Zhang Qingchun (Jon) , Agarwal Anant K.
Published: September 2009

There has been a rapid improvement in SiC materials and power devices during the last few years. SiC unipolar devices such as Schottky diodes, JFETs and MOSFETs have been developed extensively and advantages of insertion of such devices in power electronic systems have been demonstrated [1, 2]. However, unipolar devices for high voltage systems suffer from high drift layer resistance that gives rise to high power dissipation in the on‐state. For such applications, bipolar devices are preferred due to their low on‐resistance. In this article, the physics and technology of SiC bipolar devices, namely Bipolar Junction Transistors (BJTs), Insulated Gate Bipolar Transistors (IGBTs), and Gate Turn Off Thyristors (GTOs), are discussed. A detailed review of the current status and future trends in these devices is given with an emphasis on the device design and characterization. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A mass spectrometry based functional assay for the quantitative assessment of ABC transporter activity
Authors: Katona Mária , Kiss Katalin , Angyal Vilmos , Kucsma Nóra , Sarkadi Balázs , Takáts Zoltán , Szakács Gergely
Published: September 2009

ATP‐Binding Cassette (ABC) transporters are highly expressed in pharmacological barriers limiting the access of drugs to their targets. Since characterization of a compound as a transporter substrate or inhibitor bears significant consequences in drug development, there is a great need for reliable tools that enable the rapid analysis of the transport susceptibility of drugs. Here we describe a simple but very efficient high‐performance liquid chromatography/mass spectrometry (HPLC/MS) assay for measuring the ABC transporter‐dependent vesicular transport of compounds. In addition, we provide evidence that the requirement for sample preparation can be minimized using desorption electrospray ionization (DESI)‐MS, paving the way for a direct, high‐throughput investigation of drug‐transporter interactions. Copyright © 2009 John Wiley & Sons, Ltd.
Energy‐aware and entropy coding for networked‐controlled linear systems
Authors: Canudas‐de‐Wit Carlos , Jaglin Jonathan
Published: September 2009

This paper addresses issues on coding design in the context of control of systems equipped with low‐energy sensors networks. We particularly focus on issues concerning minimum bit and energy‐aware coding. To this aim, we devise a coding strategy with the ability to quantify and to differentiate stand‐still signal events from changes in the source (level crossing detector). Coding is effectuated by defining at least 3‐valued alphabet for the minimum bit case and (2L+ 1)‐valued alphabet for a general case with a precision depending onL. Energy saves are studied in two different scenarios: (1) in the word‐by‐word transmission case, the stand‐still signal event is modulated with a low‐power transmission mechanisms, whereas the changes of levels will be modulated with high power and (2) in the package‐based transmission case, an entropy variable length coding is added to the previous encoding process. Entropy coding assigns some probability distribution to the events, so that the mean transmission energy can be substantially improved for systems where the stand‐still events have higher probability to arise (i.e. stable systems). The paper studies the stability properties needed for this type of coding to operate properly, and quantify the energy saves for each of the considered scenarios. Copyright © 2009 John Wiley & Sons, Ltd.
Randomization methods for assessing data analysis results on real‐valued matrices
Authors: Ojala Markus , Vuokko Niko , Kallio Aleksi , Haiminen Niina , Mannila Heikki
Published: September 2009

Randomization is an important technique for assessing the significance of data analysis results. Given an input dataset, a randomization method samples at random from some class of datasets that share certain characteristics with the original data. The measure of interest on the original data is then compared to the measure on the samples to assess its significance. For certain types of data, e.g., gene expression matrices, it is useful to be able to sample datasets that have the same row and column distributions of values as the original dataset. Testing whether the results of a data mining algorithm on such randomized datasets differ from the results on the true dataset tells us whether the results on the true data were an artifact of the row and column statistics, or due to some more interesting phenomena in the data. We study the problem of generating such randomized datasets. We describe methods based on local transformations and Metropolis sampling, and show that the methods are efficient and usable in practice. We evaluate the performance of the methods both on real and generated data. We also show how our methods can be applied to a real data analysis scenario on DNA microarray data. The results indicate that the methods work efficiently and are usable in significance testing of data mining results on real‐valued matrices. Copyright © 2009 Wiley Periodicals, Inc., A Wiley Company
Intracellular Localization and Cytotoxicity of Spherical Mesoporous Silica Nano‐ and Microparticles
Authors: He Qianjun , Zhang Zhiwen , Gao Yu , Shi Jianlin , Li Yaping
Published: September 2009

This work evaluates the cytotoxicity of spherical mesoporous silica (MS) nano‐ and microparticles and investigates the effects of particle size, concentration, biodegradation products of MS, residual surfactant, and surfactant removal by extraction and calcination on the cytotoxicity. The results from the intracellular localization of spherical MS nano‐ and microparticles with different sizes reveal the mechanism for their cytotoxicity and that the smaller particles in nanoscale are more easily endocytosed and consequently located within lysosomes.
Twin‐reversed arterial perfusion sequence: pre‐ and postoperative cardiovascular findings in the ‘pump’ twin
Authors: Kinsel‐Ziter M. L. , Cnota J. F. , Crombleholme T. M. , Michelfelder E. C.
Published: September 2009

Objectives

To assess cardiovascular findings in twin‐reversed arterial perfusion (TRAP) sequence pre‐ and post‐therapy and compare these findings to traditional obstetric markers, defined as acardius to pump twin weight ratio and presence of polyhydramnios.

Methods

This was a retrospective review of 27 cases of TRAP sequence diagnosed between 2004 and 2008. Echocardiographic data included indexed cardiac output and functional and anatomic parameters. Ultrasound reports were reviewed for acardius to pump twin weight ratio and polyhydramnios. We assessed the relationship between cardiac output and the remaining cardiac/obstetric variables obtained pre‐ and post‐treatment.

Results

Twenty‐three subjects had complete echocardiographic data sets at initial evaluation (mean gestational age, 20.4 ± 2.5 weeks) and, of these, post‐treatment echocardiographic evaluation was available in 10. Six of seven (86%) pump twins with elevated indexed cardiac output had significant cardiovascular compromise. Most fetuses with abnormal cardiac output or right ventricular dysfunction normalized post‐therapy. There was no relationship between cardiac output and obstetric markers.

Conclusions

Elevated indexed cardiac output is strongly associated with cardiovascular compromise. Traditional obstetric prognosticators do not correlate with cardiovascular derangements. In pump twins with cardiac compromise, postoperative cardiovascular status improves acutely. Given this analysis, we conclude that assessment of cardiovascular findings should be incorporated into the management and treatment of TRAP sequence. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
The Many Faces of Rare Earth Carbodiimide Compounds
Authors: Unverfehrt Leonid , Ströbele Markus , Glaser Jochen , Meyer H.‐Jürgen
Published: September 2009

Solid state metathesis reactions have been established as a successful tool in syntheses of rare earth carbodiimide compounds. Current results evidence the new compounds LiRE(CN2)2 with RE = La, Ce and the carbodiimide nitride Ce3(CN2)3N. LiRE(CN2)2 compounds were synthesized by solid state metathesis reactions between REF3 and Li2(CN2) in 1:2 molar ratio. Ce3(CN2)3N was obtained by thermal conversion of LiCe(CN2)2., Crystal structures of LiLa(CN2)2 and Ce3(CN2)3N were determined from X‐ray single crystal data (LiLa(CN2)2: P21/m, a = 542.4(2) pm, b = 379.16(7) pm, c = 1013.0(3) pm, β = 101.35(3) °; Ce3(CN2)3N: P212121, a = 672.97(9) pm, b = 1309.8(2) pm, c = 1697.7(3) pm) and LiCe(CN2)2 was assigned from indexed X‐ray powder diffraction data (LiCe(CN2)2: a = 541.9(1) pm, b = 374.50(8) pm, c = 1008.8(2) pm, β = 101.21(1) °)., The crystal structure of LiLa(CN2)2 represents a layer‐like arrangement of ions as typical for this type of compounds. The crystal structure of Ce3(CN2)3N reveals chains of [NCe4] tetrahedra running parallel to each other, and trigonal prismatic to trigonal antiprismatic arrangements of six distinctly interconnected [Ce3–NCN–Ce3] units. Both structures contain (CN2)2– ions deviating from their ideal D∞h symmetry, with C–N distances ranging between 121 and 126 pm and N–C–N angles near 180°.
Hydrothermal Synthesis, Crystal Structure and Thermal Stability of two 3d‐4f Heterometallic Coordination Polymers
Authors: Huang Chun‐De , Qiu Tao‐Run , Wu Yi‐Yi , Mo Hai‐Hong , Zeng Rong‐Hua , Peng Guo , Wang Ning , Lu Dong‐Sheng , Fang Zhan‐Qiang
Published: September 2009

Two new 3d‐4f heterometallic coordination polymers, [LnCu(nic)2(ox)]·2H2O (Ln = Sm(1), Dy (2), ox = oxalate anion, Hnic = nicotinic acid) were synthesized and characterized by elementary analysis, IR spectroscopy and thermogravimetric analysis, as well as single‐crystal X‐ray diffraction. The two structures exhibit the same unusual 3D microporous heterometallic coordination frameworks with 13.7 % voids occupied by guest water molecules.
Pancreatic lithiasis and intraductal papillary‐mucinous neoplasm with special reference to the pathogenesis of lithiasis
Authors: Kimura Wataru
Published: September 2009

In pancreatic lithiasis in elderly autopsy cases, the stones are small and the pancreatic duct is changed very slightly when viewed by simple X‐ray film, pancreatic ductography and gross appearance. Histologically, a slight fibrous increase is seen very locally, but findings consistent with chronic pancreatitis are not found throughout the whole pancreas. However, marked, diffuse and irregular dilatation of the pancreatic duct is frequently found in operative cases with chronic pancreatitis and pancreatic stones. These findings show that the changes seen with aging and with chronic pancreatitis can be distinguished based on the findings of pancreatic ductography. Mucin production in epithelia in intraductal papillary‐mucinous neoplasm (IPMN) may not be strongly associated with the pathogenesis of pancreatic lithiasis. Pancreatic lithiasis may be related to squamous cell metaplasia. IPMN and dilatation of the pancreatic duct are closely associated with mucin production. An increase in intraductal pressure of the pancreatic duct may be somewhat related to the mechanism of stone formation. The incidental co‐existence of pancreatic epithelia with pancreatic lithiasis in patients with chronic pancreatitis and the development of IPMN may also be possible. IPMN and pancreatic lithiasis may be related through the mechanism(s) of their pathogenesis, their synergism and the pathogenesis of stone formation. The relation between mucinous metaplasia and stone formation is slight and, therefore, there may be only a weak correlation between IPMN and pancreatic stones. This may explain why there are few reports of the co‐existence of IPMN and pancreatic stones (Kimura in Kan Tan Sui 58:485–492, 2009).
Grandmothers as Gems of Genetic Wisdom: Exploring South African Traditional Beliefs About the Causes of Childhood Genetic Disorders
Authors: Penn Claire , Watermeyer Jennifer , MacDonald Carol , Moabelo Colleen
Published: September 2009

With its diverse cultural and linguistic profile, South Africa provides a unique context to explore contextual influences on the process of genetic counseling. Prior research suggests intergenerational differences regarding models of causation which influence treatment‐seeking paths. This pilot study therefore aimed to explore South African traditional beliefs regarding common childhood genetic disorders. Three focus groups were conducted with fifteen grandmothers from different cultural backgrounds in an urban community. Questions pertained to the role of the grandmother, traditional beliefs regarding causes of genetic disorders, explanations of heredity, and prevention and management of genetic disorders. Results indicate a variety of cultural explanations for causes of childhood genetic disorders. These causes can be classified into categories related to lifestyle, behavior, social issues, culture, religion, genetic, and familial causes. Prevention and treatment issues are also highlighted. These findings have implications for genetic counseling practice, which needs to include a greater focus on cultural issues.
Acoustic radiation from turbulent premixed flames
Authors: RAJARAM RAJESH , LIEUWEN TIM
Published: September 2009

Turbulent combustion processes are inherently unsteady and, thus, a source of acoustic radiation. While prior studies have extensively characterized their total sound power, their spectral characteristics are not well understood. This work investigates these acoustic spectral features, including the flame's low- and high-frequency characteristics and the scaling of the frequency of peak acoustic emissions. The spatiotemporal characteristics of the flame's chemiluminescence emissions, used as a marker of heat release fluctuations, were measured and used to determine the heat release spectrum, spatial distribution and spatial coherence characteristics. These heat release characteristics were then used as inputs to an integral solution of the wave equation and compared to measured acoustic spectra obtained over a range of conditions and burners and at several spatial locations. The spectral characteristics of the flame's acoustic emissions are controlled by two processes: the underlying spectrum of heat release fluctuations that are ultimately the combustion noise source, and the transfer function relating these heat release and acoustic fluctuations. An important result from this work is the clarification of the relative roles of these two processes in controlling the shape of the acoustic spectrum. This transfer function is primarily controlled by the spatiotemporal coherence characteristics of the heat release fluctuations which are, in turn, strongly influenced by burner configuration/geometry and operating conditions. Low-frequency acoustic emissions are controlled by the heat release spectrum essentially independent of flame geometry. Both the heat release spectrum and heat release-acoustic transfer function are important at intermediate and high frequencies. An important feature of the investigated geometry that controls the heat release phase dynamics is the high-velocity flow relative to the flame speed and anchored character of the flame. This leads to convection of flame sheet disturbances (i.e. heat release fluctuations) along the front that dominates the high frequency and peak frequency scaling of the flame's acoustic emissions.
Ventilation and clearance of the middle ear
Authors: Cohen D , Raveh D , Peleg U , Nazarian Y , Perez R
Published: September 2009

Objective:

To investigate the ventilation and drainage mechanism of the middle ear.

Study design:

Prospective.

Setting:

We observed 304 (of 337) middle ears with tympanic membrane perforation or myringotomy (102 normal, 90 with otitis media with effusion and 112 with chronic otitis media); 912 observations were recorded overall. Perforations were covered with solution, creating a fluid film, and inspected for gas bubbling at rest, and for outward and inward movement of the fluid film during swallowing. We also noted the inflammatory condition of the ear (i.e. dry, wet or purulent) and the perforation size.

Results:

Ears sometimes reacted differently in various sessions. Due to these differences, reactions were classified as ‘types’ of reactions rather than ‘ears’. We refer to 449 ‘types’ of 304 ears. Spontaneous gas bubbling at rest (indicating gas production) was observed in 98 per cent of normal types, 68 per cent of otitis media with effusion types and 65 per cent of chronic otitis media types. Evacuation towards the eustachian tube was observed in 47 per cent, no movement in 46 per cent and outward movement in 9 per cent. During swallowing, inward movement of the fluid film was observed in 74 per cent of normal types, 41 per cent of otitis media with effusion types and 32 per cent of chronic otitis media types.

Conclusions:

We found no support for the theory that the eustachian tube supplies air to the middle ear during swallowing. The normal middle ear produces gas which is evacuated by the Eustachian tube. In ears with otitis media, this mechanism appears to be impaired.
Metastatic cutaneous squamous cell carcinoma of the external ear: a high-risk cutaneous subsite
Authors: Turner S J , Morgan G J , Palme C E , Veness M J
Published: September 2009

Introduction:

Patients with cutaneous squamous cell carcinoma of the external ear may develop metastatic spread to the nearby ipsilateral parotid and/or upper cervical lymph nodes. The literature suggests that the external ear is a high-risk subsite for such tumours, due to nodal metastasis and its associated morbidity and mortality.

Methods:

Between 1980 and 2007, 43 patients with a diagnosis of metastatic cutaneous squamous cell carcinoma of the external ear were treated with surgery alone, surgery plus adjuvant radiotherapy, or radiotherapy alone.

Results:

Patients comprised 39 men and four women. Their median age at diagnosis was 72 years, with a median follow up of 35 months. The median size of the primary lesion was 21 mm, with a median thickness of 7 mm. Fifteen patients presented concurrently with nodal metastases. Thirty patients developed parotid metastases (with positive cervical nodes in six patients), while 13 developed cervical metastases only. Eight patients underwent surgery alone, 32 underwent surgery plus adjuvant radiotherapy, and three received radiotherapy alone. At the last follow up, 15 patients had relapsed and nine had died of their disease, with a median survival after relapse of 5.5 months.

Conclusion:

Patients with metastatic cutaneous squamous cell carcinoma of the external ear have a relatively poor outcome, with a significant number of patients experiencing nodal relapse and death after treatment.
A new species ofThaumastoderma(Gastrotricha: Macrodasyida) from the Antarctic deep sea with a phylogenetic analysis of the whole genus
Authors: Kieneke Alexander
Published: September 2009

A new species of the marine gastrotrich taxonThaumastodermais described. A single specimen of this species,Thaumastoderma antarcticasp. nov., was extracted from silty sediment sampled at one station of the Andeep-1 cruise, about 150 km to the north of the South Shetland Islands (Drake Passage, South Atlantic Ocean). This paper provides the first record of this genus from the deep sea and the second description of a macrodasyid gastrotrich living in an abyssal habitat. The new species is characterized by several apomorphic features, among them a caudal pair of strongly elongated dorsal cirrata tubes. A phylogenetic analysis of the genusThaumastodermareveals thatTh. antarcticais closely related toTh. coronariumandTh. appendiculatum. Furthermore, the analysis offers an evolutionary scenario and a hypothesis for the internal phylogeny of this taxon while supporting its monophyly. It is the first time a cladistic analysis has been conducted for a delimited group of gastrotrichs, i.e. for all known members of a genus.
Case management for long-term conditions: implementation and processes
Authors: REILLY SIOBHAN , HUGHES JANE , CHALLIS DAVID
Published: September 2009

This paper presents a structured literature review that focused on comprehensive case management by nurses for adults with long-term conditions living in the community. The emphases of the review are the implementation of case-management approaches, including its roles, core tasks and components, and the coverage and quality of the reported implementation data. Twenty-nine studies were included: the majority were concerned with case management for frail older people, and others focused on people with multiple chronic diseases, high-cost patients, or those at high risk of hospital admissions. All the studies reported that case managers undertook the core tasks of assessment, care planning and the implementation of the care plan, but there was more variation in who carried out case finding, monitoring, review and case closure. Few studies provided adequate implementation information. On the basis of the reviewed evidence, three issues were identified as key to the coherent and sustainable implementation of case management for people with long-term conditions: fidelity to the core elements of case management; size of caseload; and case-management practice, incorporating matters relating to the continuity of care, the intensity and breadth of involvement, and control over resources. It is recommended that future evaluations of case-management interventions include a comprehensive process component or, at the very least, that interventions should be more fully described.
A methodology for static stiffness mapping in lower mobility parallel manipulators with decoupled motions
Authors: Pinto Charles , Corral Javier , Altuzarra Oscar , Hernández Alfonso
Published: September 2009

In this paper a general methodology for obtaining static stiffness maps in lower mobility parallel manipulators is proposed. The main objective is to define a set of guidelines, which allow the experimental work to be optimized and computational time to be reduced. First, a two-degree-of-freedom (DOF) mechanism will be used for methodology validation, since it is the stiffness of the basic kinematic chain of the manipulator that is to be analysed. Two mathematical models of this mechanism and an experimental prototype will be considered for the validation. After that, the methodology will be applied to a lower mobility (4-DOF) parallel manipulator. In this paper, the experimental prototype and its set-up is highly important because some particular features of the experimental analysis will be defined. This paper introduces a key experimental tool: the preload, which allows the clearances and possible assembling errors to be considered. The added value from the application of this procedure is the obtaining of graphs that describe, in an intuitive and useful way, the behaviour of the manipulator's stiffness inside its workspace as a function of the mobile platform position and orientation.