bluuebunny/crossref_metadata_2025 huggingface dataset:
Role‐reversal of gender‐associated mitochondrial DNA affects mitochondrial function in Mytilus edulis (Bivalvia: Mytilidae)
Authors: Breton Sophie , Stewart Donald T. , Blier Pierre U.
Published: December 2008

Mussel species of the genus Mytilus possess an unusual system of mitochondrial DNA (mtDNA) transmission termed doubly uniparental inheritance. They are characterized by the presence of two highly divergent gender‐associated mtDNA genomes (often with>20 and>10% divergences in DNA and amino acid sequences, respectively) that are inherited either maternally (F mtDNA) or paternally (M mtDNA). Females are typically homoplasmic for the F mtDNA and males are heteroplasmic with the F mtDNA being most common in all tissues except the gonad that is dominated by the M mtDNA. Collectively, males are polymorphic for two classes of M mtDNAs known as the “standard male” and “recently masculinized” M types (SM and RM, respectively). The coding portions of the RM mtDNA genome differ from the SM mtDNA by as much as the maternally inherited F mtDNA genome differs from the SM type. Because the SM and RM types exhibit considerable amino acid sequence divergence, we hypothesized that these differences could affect mitochondrial respiratory chain complex enzyme activities. To test this hypothesis, the activity of the major mitochondrial respiratory chain complexes (complexes II, I+III and IV) as well as the activity of citrate synthase were measured on gonad samples from males containing either the SM or RM mtDNA. Our data demonstrate that the mitochondrial subunits encoded by the RM mtDNA are associated with higher enzymatic activities than the gene products of the SM mtDNA. J. Exp. Zool. (Mol. Dev. Evol.) 312B:108–117, 2009. © 2008 Wiley‐Liss, Inc.
Temporal analysis of ectopic enamel production in incisors from sprouty mutant mice
Authors: Boran Tomas , Peterkova Renata , Lesot Herve , Lyons David B. , Peterka Miroslav , Klein Ophir D.
Published: December 2008

The mouse incisor has two unusual features: it grows continuously and it is covered by enamel exclusively on the labial side. The continuous growth is driven in part by epithelial stem cells in the cervical loop region that can both self‐renew and give rise to ameloblasts. We have previously reported that ectopic enamel is found on the lingual side of the incisor in mice with loss‐of‐function of sprouty (spry) genes. Spry2+/−; Spry4−/− mice, in which three sprouty alleles have been inactivated, have ectopic enamel as a result of upregulation of epithelial‐mesenchymal FGF signaling in the lingual part of the cervical loop. Interestingly, lingual enamel is also present in the early postnatal period in Spry4−/− mice, in which only two sprouty alleles have been inactivated, but ectopic enamel is not found in adults of this genotype. To explore the mechanisms underlying the disappearance of lingual enamel in Spry4−/− adults, we studied the fate of the lingual enamel in Spry4−/− mice by comparing the morphology and growth of their lower incisors with wild type and Spry2+/−; Spry4−/− mice at several timepoints between the perinatal period and adulthood. Ameloblasts and enamel were detected on the lingual side in postnatal Spry2+/−; Spry4+/− incisors. By contrast, new ectopic ameloblasts ceased to differentiate after postnatal day 3 in Spry4−/− incisors, which was followed by a progressive loss of lingual enamel. Both the posterior extent of lingual enamel and the time of its last deposition were variable early postnatally in Spry4−/− incisors, but in all Spry4−/− adult incisors the lingual enamel was ultimately lost through continuous growth and abrasion of the incisor. J. Exp. Zool. (Mol. Dev. Evol.) 312B:473–485, 2009. © 2009 Wiley‐Liss, Inc.
Vibrational spectra and potential energy distributions for 1‐benzyl‐1H‐imidazole by normal coordinate analysis
Authors: James C. , Ravikumar C. , Jayakumar V. S. , Hubert Joe I.
Published: December 2008

The Fourier‐transform (FT) Raman and infrared (IR) spectra of the crystallized novel pharmaceutical molecule 1‐benzyl‐1H‐imidazole (BI) were recorded and analyzed. The geometry, intermolecular hydrogen bond, and harmonic vibrational wavenumbers of BI were investigated with the help of B3PW91 density functional theory (DFT) methods. The detailed interpretation of the vibrational spectra was carried out with the aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMFF). The aromaticities of the imidazole and phenyl rings were studied using the standard harmonic oscillator model of aromaticity (HOMA) index. Natural bond orbital (NBO) analysis on BI was carried out to demonstrate the various intramolecular interactions that are responsible for the stabilization of this molecule leading to its medicinal activity. The potential energy profile corresponding to the torsion around the bridge bonds connecting the two rings was drawn to explain the steric and/or electronic effects using potential energy surface (PES) scan studies. The pronounced double‐bond localization in the imidazole ring upon intermolecular H‐bonding appears to be the cause for its enhanced aromaticity. Copyright © 2008 John Wiley & Sons, Ltd.
Quantitative capillary electrophoresis and its application in analysis of alkaloids in tea, coffee, coca cola, and theophylline tablets
Authors: Li Mengjia , Zhou Junyi , Gu Xue , Wang Yan , Huang Xiaojing , Yan Chao
Published: December 2008

A quantitative CE (qCE) system with high precision has been developed, in which a 4‐port nano‐valve was isolated from the electric field and served as sample injector. The accurate amount of sample was introduced into the CE system with high reproducibility. Based on this system, consecutive injections and separations were performed without voltage interruption. Reproducibilities in terms of RSD lower than 0.8% for retention time and 1.7% for peak area were achieved. The effectiveness of the system was demonstrated by the quantitative analysis of caffeine, theobromine, and theophylline in real samples, such as tea leaf, roasted coffee, coca cola, and theophylline tablets.
Fast Synthesis of Nanostructured Microspheres of a Bridged Silsesquioxane via Ultrasound‐Assisted Sol–Gel Processing
Authors: Romeo Hernán E. , Fanovich María A. , Williams Roberto J. J. , Matějka Libor , Pleštil Josef , Brus Jiří
Published: December 2008

Microspheres of a nanostructured bridged silsesquioxane were synthesized by employing ultrasound‐assisted self‐assembly of a bridged monomer via sol–gel processing. The bridged precursor was synthesized from glycidoxypropyl(trimethoxysilane) (GPMS) (2 mol) and cyclohexylamine (1 mol). The main factor controlling the generation of a stable dispersion of microspheres was the time at which the phase separation of the silsesquioxane was produced during the hydrolytic condensation. An appropriate blend of THF/n‐hexane as a solvent enabled to rapidly generate a stable dispersion exhibiting a low polydispersity. The mild reaction conditions produced the nanostructuring of the silsesquioxane characterized by a fine structure in SAXS spectrum. Inorganic domains were arranged in a two‐dimensional hexagonal system leading to the formation of cavities in the microspheres which could be employed as host–guest systems in advanced technologies.

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Rasch analysis of the hospital anxiety and depression scale in Parkinson's disease
Authors: Forjaz Maria João , Rodriguez‐Blázquez Carmen , Martinez‐Martin Pablo ,   on behalf of the Longitudinal Parkinson's Disease Patient Study (Estudio Longitudinal de Pacientes con Enfermedad de Parkinson—ELEP) Group
Published: December 2008

The hospital anxiety and depression scale (HADS) is commonly used to assess mood in Parkinson's disease (PD) patients. Very few studies analyze the scale from the standpoint of item response theory. This article sought to analyze how the HADS fits the Rasch model in PD. The HADS was administered to 387 PD patients. Three sets of Rasch analyses were performed for the HADS total score, and anxiety and depression subscales (HADS‐T, ‐A, and ‐D, respectively). Although the HADS‐T and HADS‐A displayed a good fit, with little threshold disordering and no differential item functioning, the HADS‐D failed to fit the model. The person separation index, a reliability measure, was 0.87 (HADS‐T) and 0.80 (HADS‐A). Both HADS‐T and HADS‐A showed unidimensionality. Our results supported the use of HADS‐T as a measure of psychological distress in PD patients. Moreover, the HADS‐A was also an adequate anxiety measure. Further research is required to address the use of HADS‐D in PD. © 2008 Movement Disorder Society
Resurfacing of a complex upper extremity injury: An excellent indication for the dorsal thoracic fascial flap
Authors: Hazani Ron , Brooks Darrell , Buntic Rudolf F.
Published: December 2008

We report a case of a 24‐year‐old patient who sustained a mutilating crush injury to the left forearm. After thorough debridement and stabilization of the skeletal injury, the dorsal thoracic fascial flap was used to resurface the circumferential wound, protect the underlying structures, and provide a gliding surface for the exposed tendons. The flap was safely transected during revision surgery, and at 6‐months follow‐up, excellent functional and cosmetic results were achieved. The dorsal thoracic fascia is a thin, durable, and pliable tissue that is based on a long vascular pedicle. We consider the dorsal thoracic fascial flap as a valuable option for coverage of complex upper extremity injuries and highly recommend its use. © 2008 Wiley‐Liss, Inc. Microsurgery, 2009.
Whole‐body imaging at 7T: Preliminary results
Authors: Vaughan J. Thomas , Snyder Carl J. , DelaBarre Lance J. , Bolan Patrick J. , Tian Jinfeng , Bolinger Lizann , Adriany Gregor , Andersen Peter , Strupp John , Ugurbil Kamil
Published: December 2008

The objective of this study was to investigate the feasibility of whole‐body imaging at 7T. To achieve this objective, new technology and methods were developed. Radio frequency (RF) field distribution and specific absorption rate (SAR) were first explored through numerical modeling. A body coil was then designed and built. Multichannel transmit and receive coils were also developed and implemented. With this new technology in hand, an imaging survey of the “landscape” of the human body at 7T was conducted. Cardiac imaging at 7T appeared to be possible. The potential for breast imaging and spectroscopy was demonstrated. Preliminary results of the first human body imaging at 7T suggest both promise and directions for further development. Magn Reson Med 61:244–248, 2009. © 2008 Wiley‐Liss, Inc.
Implementation of three‐dimensional wavelet encoding spectroscopic imaging: In vivo application and method comparison
Authors: Young Richard , Serrai Hacene
Published: December 2008

We have recently proposed a two‐dimensional Wavelet Encoding‐Spectroscopic Imaging (WE‐SI) technique as an alternative to Chemical Shift Imaging (CSI), to reduce acquisition time and crossvoxel contamination in magnetic resonance spectroscopic imaging (MRSI). In this article we describe the extension of the WE‐SI technique to three dimensions and its implementation on a clinical 1.5 T General Electric (GE) scanner. Phantom and in vivo studies are carried out to demonstrate the usefulness of this technique for further acquisition time reduction with low voxel contamination. In wavelet encoding, a set of dilated and translated prototype functions called wavelets are used to span a localized space by dividing it into a set of subspaces with predetermined sizes and locations. In spectroscopic imaging, this process is achieved using radiofrequency (RF) pulses with profiles resembling the wavelet shapes. Slice selective excitation and refocusing RF pulses, with single‐band and dual‐band profiles similar to Haar wavelets, are used in a modified PRESS sequence to acquire 3D WE‐SI data. Wavelet dilation and translation are achieved by changing the strength of the localization gradients and frequency shift of the RF pulses, respectively. The desired spatial resolution in each direction sets the corresponding number of dilations (increases in the localization gradients), and consequently, the number of translations (frequency shift) of the Haar wavelets (RF pulses), which are used to collect magnetic resonance (MR) signals from the corresponding subspaces. Data acquisition time is reduced by using the minimum recovery time (TRmin), also called effective time, when successive MR signals from adjacent subspaces are collected. Inverse wavelet transform is performed on the acquired data to produce metabolite maps. The proposed WE‐SI method is compared in terms of acquisition time, pixel bleed, and signal‐to‐noise ratio to the CSI technique. The study outcome shows that 3D WE‐SI provides accurate results while reducing both acquisition time and voxel contamination. Magn Reson Med 61:6–15, 2009. © 2008 Wiley‐Liss, Inc.
Mechanical model of neural tissue displacement during Lorentz effect imaging
Authors: Roth Bradley J. , Basser Peter J.
Published: December 2008

Allen Song and coworkers recently proposed a method for MRI detection of biocurrents in nerves called “Lorentz effect imaging.” When exposed to a magnetic field, neural currents are subjected to a Lorentz force that moves the nerve. If the displacement is large enough, an artifact is predicted in the MR signal. In this work, the displacement of a nerve of radius a in a surrounding tissue of radius b and shear modulus μ is analyzed. The nerve carries a current density J and lies in a magnetic field B. The solution to the resulting elasticity problem indicates that the nerve moves a distance
$BJ/4|gm$a2ln($b/a$). Using realistic parameters for a human median nerve in a 4T field, this calculated displacement is 0.013 μm or less. The distribution of displacement is widespread throughout the tissue, and is not localized near the nerve. This displacement is orders of magnitude too small to be detected by conventional MRI methods. Magn Reson Med 61:59–64, 2009. © 2008 Wiley‐Liss, Inc.
Influence of RF spoiling on the stability and accuracy of T1 mapping based on spoiled FLASH with varying flip angles
Authors: Preibisch C. , Deichmann R.
Published: December 2008

There is increasing interest in quantitative T1 mapping techniques for a variety of applications. Several methods for T1 quantification have been described. The acquisition of two spoiled gradient‐echo data sets with different flip angles allows for the calculation of T1 maps with a high spatial resolution and a relatively short experimental duration. However, the method requires complete spoiling of transverse magnetization. To achieve this goal, RF spoiling has to be applied. In this work it is investigated whether common RF spoiling techniques are sufficiently effective to allow for accurate T1 quantification. It is shown that for most phase increments the apparent T1 can deviate considerably from the true value. Correct results may be achieved with phase increments of 118.2° or 121.8°. However, for these values the method suffers from instabilities. In contrast, stable results are obtained with a phase increment of 50°. An algorithm is presented that allows for the calculation of corrected T1 maps from the apparent values. The method is tested both in phantom experiments and in vivo by acquiring whole‐brain T1 maps of the human brain. Magn Reson Med 61:125–135, 2009. © 2008 Wiley‐Liss, Inc.
Efficient multiple acquisitions by skipped phase encoding and edge deghosting (SPEED) using shared spatial information
Authors: Chang Zheng , Xiang Qing‐San , Ji Jim , Yin Fang‐Fang
Published: December 2008

The fast MRI method of Skipped Phase Encoding and Edge Deghosting (SPEED) is further developed to accelerate multiple acquisitions. In a single acquisition, SPEED first acquires three sparse ghosted edge maps with an undersampling factor of N/3, which are modeled with a double‐layer structure and described by three equations with two unknown ghosts, each with a unique ghost order index. By minimizing least‐square‐error, a pair of ghost order indexes is determined. Based on them, the two corresponding ghosts are resolved, leading to a deghosted image. In this case, three equations are needed to determine the ghost order index, while only two equations are required to resolve the two ghosts. This shows both inefficiency and potential. Multiple acquisitions often contain similar spatial information. The similarities can be used to improve efficiency by sharing the ghost order index among different acquisitions, leading to acceleration factors greater than that achievable with single acquisition. Magn Reson Med 61:229–233, 2009. © 2008 Wiley‐Liss, Inc.
MR imaging during endovascular procedures: An evaluation of the potential for catheter heating
Authors: Martin Alastair J. , Baek Bryant , Acevedo‐Bolton Gabriel , Higashida Randall T. , Comstock John , Saloner David A.
Published: December 2008

MRI in catheterized patients is considered unsafe due to the potential for focal heating. This concern arises from the continuous metallic braid that is incorporated into catheters to provide their desired physical properties. The potential for catheter heating during MR scanning was assessed in an in vitro model simulating a patient undergoing a neurovascular procedure in which MR scans of the brain will be performed. Heating adjacent to endovascular devices was assessed with fluoroptic temperature probes in a polyacrylamide gel. The effect of variable immersion lengths, lateral and longitudinal offsets, position along the endovascular device, physical MR system, and specific absorption rate (SAR) level were studied to determine their effect on catheter heating. A rapid temperature rise was evident next to endovascular devices during MR scanning and varied moderately with immersed length, position within the bore, measurement point on the device, and MR system used. Peak heating rates were less than 1°C/min with maximal SAR exposure and anatomically realistic geometries. Heating scaled linearly with SAR and SAR values below 0.2 W/kg produced negligible heating near catheters. For the evaluated application, substantial SAR restrictions, coupled with limited imaging durations, are proposed as sufficient to permit MRI without concern for thermal injury. Magn Reson Med 61:45–53, 2009. © 2008 Wiley‐Liss, Inc.
Turboprop IDEAL: A motion‐resistant fat–water separation technique
Authors: Huo Donglai , Li Zhiqiang , Aboussouan Eric , Karis John P. , Pipe James G.
Published: December 2008

Suppression of the fat signal in MRI is very important for many clinical applications. Multi‐point water–fat separation methods, such as IDEAL (Iterative Decomposition of water and fat with Echo Asymmetry and Least‐squares estimation), can robustly separate water and fat signal, but inevitably increase scan time, making separated images more easily affected by patient motions. PROPELLER (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction) and Turboprop techniques offer an effective approach to correct for motion artifacts. By combining these techniques together, we demonstrate that the new TP‐IDEAL method can provide reliable water–fat separation with robust motion correction. The Turboprop sequence was modified to acquire source images, and motion correction algorithms were adjusted to assure the registration between different echo images. Theoretical calculations were performed to predict the optimal shift and spacing of the gradient echoes. Phantom images were acquired, and results were compared with regular FSE‐IDEAL. Both T1‐ and T2‐weighted images of the human brain were used to demonstrate the effectiveness of motion correction. TP‐IDEAL images were also acquired for pelvis, knee, and foot, showing great potential of this technique for general clinical applications. Magn Reson Med 61:188–195, 2009. © 2008 Wiley‐Liss, Inc.
Long‐range diffusion of hyperpolarized 3He in rats
Authors: Rodríguez Ignacio , Pérez‐Sánchez José Manuel , Peces‐Barba Germán , Kaulisch Thomas , Stiller Detlef , Ruiz‐Cabello Jesús
Published: December 2008

Based on a stimulated‐echo technique, a method to construct an apparent diffusion coefficient (ADC) map of hyperpolarized 3He in a long‐range diffusion scale is presented with a phase‐cycle alternative to remove all unwanted echoes. The approach was successfully applied to determine in vivo diffusion constants in rat lungs. The ADC values in healthy rats show a good agreement with reported values for diffusion times of ≈. These long diffusivity measurements may be sensitive to detect emphysema progression or tissue remodeling and thus have enormous potential for the diagnosis and tracking of disease progression and for drug evaluation. Magn Reson Med 61:54–58, 2009. © 2008 Wiley‐Liss, Inc.
Orientation of lipid strands in the extracellular compartment of muscle: Effect on quantitation of intramyocellular lipids
Authors: Khuu Anthony , Ren Jimin , Dimitrov Ivan , Woessner Donald , Murdoch James , Sherry A. Dean , Malloy Craig R.
Published: December 2008

Single‐voxel 1H NMR spectra from gastrocnemius and soleus muscle were acquired in healthy volunteers at 7T with the objective of measuring the concentration of intramyocellular lipid [IMCL] (note: throughout this article, square brackets indicate concentration). However, significant asymmetry in the resonance assigned to the methylene protons (‐CH2‐)n in extramyocellular lipids (EMCL) interfered with fitting the spectra. Since muscle fibers in these tissues are generally not parallel to B0, the influence of variable orientation in strands of extracellular fat was examined using a mathematical model. Modest variation in orientation produced asymmetric lineshapes that were qualitatively similar to typical observations at 7T. Analysis of simulated spectra by fitting with a Voigt function overestimated [IMCL]/[EMCL] except when EMCL fibers were nearly parallel to B0. Estimates of [IMCL]/[EMCL] were improved by including variations in fiber orientation in the lineshape analysis (fiber orientation modeling, or FOM). Calculated [IMCL] using FOM, 4.8 ± 2.2 mmol/kg wet weight, was lower compared to most previous reports in soleus. Magn Reson Med 61:16–21, 2009. © 2008 Wiley‐Liss, Inc.
Design of cosine modulated very selective suppression pulses for MR spectroscopic imaging at 3T
Authors: Osorio Joseph A. , Xu Duan , Cunningham Charles H. , Chen Albert , Kerr Adam B. , Pauly John M. , Vigneron Daniel B. , Nelson Sarah J.
Published: December 2008

The advantages of using a 3 Tesla (T) scanner for MR spectroscopic imaging (MRSI) of brain tissue include improved spectral resolution and increased sensitivity. Very selective saturation (VSS) pulses are important for maximizing selectivity for PRESS MRSI and minimizing chemical shift misregistration by saturating signals from outside the selected region. Although three‐dimensional (3D) PRESS MRSI is able to provide excellent quality metabolic data for patients with brain tumors and has been shown to be important for defining tumor burden, the method is currently limited by how much of the anatomic lesion can be covered within a single examination. In this study we designed and implemented cosine modulated VSS pulses that were optimized for 3T MRSI acquisitions. This provided improved coverage and suppression of unwanted lipid signals with a smaller number of pulses. The use of the improved pulse sequence was validated in volunteer studies, and in clinical 3D MRSI exams of brain tumors. Magn Reson Med, 2009. © 2008 Wiley‐Liss, Inc.
Transverse relaxation and magnetization transfer in skeletal muscle: Effect of pH
Authors: Louie Elizabeth A. , Gochberg Daniel F. , Does Mark D. , Damon Bruce M.
Published: December 2008

Exercise increases the intracellular T2 (T2,i) of contracting muscles. The mechanism(s) for the T2,i increase have not been fully described, and may include increased intracellular free water and acidification. These changes may alter chemical exchange processes between intracellular free water and proteins. In this study, the hypotheses were tested that (a) pH changes T2,i by affecting the rate of magnetization transfer (MT) between free intracellular water and intracellular proteins, and (b) the magnitude of the T2,i effect depends on acquisition mode (localized or nonlocalized) and echo spacing. Frog gastrocnemius muscles were excised and their intracellular pH was either kept at physiological pH (7.0) or modified to model exercising muscle (pH 6.5). The intracellular transverse relaxation rate (R2,i = 1/T2,i) always decreased in the acidic muscles, but the changes were greater when measured using more rapid refocusing rates. The MT rate from the macromolecular proton pool to the free water proton pool, its reverse rate, and the spin‐lattice relaxation rate of water decreased in acidic muscles. It is concluded that intracellular acidification alters the R2,i of muscle water in a refocusing rate‐dependent manner, and that the R2,i changes are correlated with changes in the MT rate between macromolecules and free intracellular water. Magn Reson Med, 2009. © 2008 Wiley‐Liss, Inc.
Fat/water separation using a concentric rings trajectory
Authors: Wu Hochong H. , Lee Jin Hyung , Nishimura Dwight G.
Published: December 2008

The concentric rings two‐dimensional (2D) k‐space trajectory enables flexible trade‐offs between image contrast, signal‐to‐noise ratio (SNR), spatial resolution, and scan time. However, to realize these benefits for in vivo imaging applications, a robust method is desired to deal with fat signal in the acquired data. Multipoint Dixon techniques have been shown to achieve uniform fat suppression with high SNR‐efficiency for Cartesian imaging, but application of these methods for non‐Cartesian imaging is complicated by the fact that fat off‐resonance creates significant blurring artifacts in the reconstruction. In this work, two fat–water separation algorithms are developed for the concentric rings. A retracing design is used to sample rings near the center of k‐space through multiple revolutions to characterize the fat–water phase evolution difference at multiple time points. This acquisition design is first used for multipoint Dixon reconstruction, and then extended to a spectroscopic approach to account for the trajectory's full evolution through 3D k‐t space. As the trajectory is resolved in time, off‐resonance effects cause shifts in frequency instead of spatial blurring in 2D k‐space. The spectral information can be used to assess field variation and perform robust fat–water separation. In vivo experimental results demonstrate the effectiveness of both algorithms. Magn Reson Med, 2009. © 2008 Wiley‐Liss, Inc.
Magnetic resonance imaging quantification of left ventricular dysfunction following coronary microembolization
Authors: Carlsson Marcus , Martin Alastair J , Ursell Philip C , Saloner David , Saeed Maythem
Published: December 2008

Microembolization is common after coronary interventions, and therefore this MRI study aimed to quantify the effect of coronary microembolization on left ventricular (LV) function. The left anterior descending artery (LAD) was selectively catheterized in an XMR suite (Philips Medical Systems, Best, The Netherlands) in eight pigs to deliver MR contrast media to measure the LAD territory using first‐pass perfusion and for intracoronary delivery of the embolic agent. Cine, tagged, and delayed contrast‐enhanced MRI (DCE‐MRI) was performed to assess LV volumes, ejection fraction, radial and circumferential strain, and viability at baseline, 1 h, and 1 week after microembolization. Histopathology and histochemical staining were used to characterize and measure the extent of microinfarction. The LAD territory was 35% ± 2% LV mass. Patchy microinfarction on DCE‐MRI at 1 week was 22.0% ± 3.6% LAD territory (7.5% LV mass). Microembolization caused persistent decline in ejection fraction (baseline = 49% ± 1%, 1 h = 29% ± 1%, P = 0.02 and 1 week = 36% ± 1%, P = 0.03) and increased end‐diastolic (79.6 ± 3.9 ml, 85.5 ± 4.5 ml, P = 0.03 and 92.4 ± 6.2 ml, P = 0.06, respectively) and end‐systolic (40.8 ± 2.1 ml, 60.2 ± 3.4 ml, P = 0.02 and 59.3 ± 4.8 ml, P = 0.03, respectively) volumes. The microembolized territory was manifested as dysfunctional regions for 1 week on cine and tagged MRI. Histopathology revealed occlusive microemboli surrounded by necrotic tissue undergoing repair. Microinfarction was visualized after coronary microembolization and caused LV dysfunction disproportionate to the size of myocardial damage. It also changed LV geometry and decreased radial and circumferential strain over the course of 1 week. Magn Reson Med, 2009. © 2008 Wiley‐Liss, Inc.
On using T2 to assess extrinsic magnetic field inhomogeneity effects on T2* measurements in myocardial siderosis in thalassemia
Authors: He Taigang , Smith Gillian C. , Gatehouse Peter D. , Mohiaddin Raad H. , Firmin David N. , Pennell Dudley J.
Published: December 2008

Magnetic resonance T2* has been validated as a noninvasive means of assessing myocardial iron overload. However, the effect on myocardial T2* of factors such as shimming, variations in capillary geometry, and susceptibility in relation to the effects of iron has not been fully clarified. Since T2 is not affected by extrinsic magnetic field inhomogeneity and has different sensitivity to capillary geometry, investigation into the in vivo relationship between myocardial T2* and T2 measurements can shed light on this important issue. This study was performed in 136 thalassemia patients. The myocardial T2 and T2* thresholds for normality created identical no‐iron‐overload and iron‐overloaded patient groups. In the no‐iron group, there was no correlation between myocardial T2 and T2*. In the iron‐overloaded patients, there was a linear correlation (R2 = 0.89) between myocardial T2* and T2 measurements, which indicates that the iron deposition is the dominant factor in determining these two relaxation values in this scenario. Magn Reson Med, 2009. © 2008 Wiley‐Liss, Inc.
k‐TE generalized autocalibrating partially parallel acquisition (GRAPPA) for accelerated multiple gradient‐recalled echo (MGRE) R2* mapping in the abdomen
Authors: Yin Xiaoming , Larson Andrew C.
Published: December 2008

Multiple gradient‐recalled echo (MGRE) methods are commonly used for abdominal R2* mapping. Accelerated MGRE acquisitions would offer the potential to shorten requisite breathhold times and/or increase spatial resolution and coverage. In both phantom and normal volunteer studies, view‐sharing (VS) methods, generalized autocalibrating partially parallel acquisition (GRAPPA) methods, and newly proposed k–echo time (k‐TE) GRAPPA methods were compared for the purpose of accelerating MGRE acquisitions. Utilization of water‐selective spatial spectral excitation pulses reduced artifact levels for both VS and k‐TE GRAPPA approaches. VS approaches were found to be highly sensitive to off‐resonance effects, particularly at increasing acceleration rates. k‐TE GRAPPA significantly reduced residual artifact levels compared to GRAPPA approaches while improving the accuracy of accelerated abdominal R2* measurements. These initial feasibility studies demonstrate that k‐TE GRAPPA is an effective method to reduce scan times during abdominal R2*‐mapping procedures. Magn Reson Med, 2009. © 2008 Wiley‐Liss, Inc.
A stable Lagrange multiplier space for stiff interface conditions within the extended finite element method
Authors: Béchet Éric , Moës Nicolas , Wohlmuth Barbara
Published: December 2008

This paper introduces a new algorithm to define a stable Lagrange multiplier space to impose stiff interface conditions within the context of the extended finite element method. In contrast to earlier approaches, we do not work with an interior penalty formulation as, e.g. for Nitsche techniques, but impose the constraints weakly in terms of Lagrange multipliers. Roughly speaking a stable and optimal discrete Lagrange multiplier space has to satisfy two criteria: a best approximation property and a uniform inf–sup condition. Owing to the fact that the interface does not match the edges of the mesh, the choice of a good discrete Lagrange multiplier space is not trivial. Here we propose a new algorithm for the local construction of the Lagrange multiplier space and show that a uniform inf–sup condition is satisfied. A counterexample is also presented, i.e. the inf–sup constant depends on the mesh‐size and degenerates as it tends to zero. Numerical results in two‐dimensional confirm the theoretical ones. Copyright © 2008 John Wiley & Sons, Ltd.
C‐terminal Tensin‐like (CTEN) is an oncogene which alters cell motility possibly through repression of E‐cadherin in colorectal cancer
Authors: Albasri Abdulkader , Seth Rashmi , Jackson Darryl , Benhasouna Ahmed , Crook Simon , Nateri Abdolrahman S. , Chapman Roger , Ilyas Mohammad
Published: December 2008

The Tensin gene family encodes proteins thought to modulate integrin function. C‐terminal Tensin‐like (CTEN) is a member of the Tensin gene family which lacks the N‐terminus actin‐binding domain. Cten is reported to have both oncogenic and tumour‐suppressor functions. We investigated the role that Cten may play in colorectal cancer (CRC). By quantitative RT–PCR CTEN is up‐regulated (i.e. > two‐fold increase) in 62% of cell lines and 69% of tumours compared with normal mucosa, consistent with CTEN being a possible oncogene. Stable transfection of HCT116 and SW480 (CRC cell lines with low endogenous Cten expression) with a Cten expression vector gave identical results in both cell lines. Forced Cten expression did not cause change in cell numbers, although it did confer resistance to staurosporine‐induced apoptosis (p < 0.005). Cten also induced epithelial–mesenchymal transition (EMT) in tumour cells accompanied by a significant increase in both cell migration (transwell migration and cell wounding assays, p < 0.001 and p < 0.05, respectively) and cell invasion (invasion through Matrigel, p < 0.001). Given the observed EMT, we investigated the levels of E‐cadherin. Cten induction was associated with a reduction in E‐cadherin protein expression but not levels of E‐cadherin mRNA. These data suggest that CTEN is an oncogene in CRC which stimulates EMT, cell migration and invasion and may therefore have a role in tumour invasion/spread. Furthermore, Cten induction is associated with post‐transcriptional repression of E‐cadherin. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
PGD for monogenic disorders: aspects of molecular biology
Authors: Spits Claudia , Sermon Karen
Published: December 2008

Preimplantation genetic diagnosis (PGD) for monogenic diseases has known a considerable evolution since its first application in the early 1990s. Especially the technical aspects of the genetic diagnosis itself, the single‐cell genetic analysis, has constantly evolved to reach levels of accuracy and efficiency nearing those of genetic diagnosis on regular DNA samples. In this review, we will focus on the molecular biological techniques that are currently in use in the most advanced centers for PGD for monogenic disorders, including multiplex polymerase chain reaction (PCR) and post‐PCR diagnostic methods, whole genome amplification (WGA) and multiple displacement amplification (MDA). As it becomes more and more clear that when it comes to ethically difficult indications, PGD goes further than prenatal diagnosis (PND), we will also briefly discuss ethical issues. Copyright © 2008 John Wiley & Sons, Ltd.
Mössbauer119Sn and XPS spectroscopy of Sn2P2S6and SnP2S6crystals
Authors: Vysochanskii Yu. M. , Baltrunas D. , Grabar A. A. , Mazeika K. , Fedyo K. , Sudavicius A.
Published: December 2008

The monoclinic Sn2P2S6and rombohedral layered SnP2S6crystals have been investigated by119Sn Mössbauer and X‐ray photoelectron spectroscopies. By comparing the isomer shift, quadrupole splitting and binding energies for Sn 3d and 4d core levels in these crystals with such parameters for the metal tin and for different tin compounds it was found that in the Sn2P2S6crystals Sn existed in the Sn2+oxidation state and in the SnP2S6crystals – in the Sn4+state. Temperature dependences of the isomer shift and Debye–Waller factor satisfied the Debye model in the temperature interval of 6 – 300 K for the SnP2S6crystals but deviated from such behavior atT> 250 K for Sn2P2S6crystals. This peculiarity together with specific character of the temperature dependence of the quadrupole splitting were related to the role of the stereoactive Sn 5s2lone pair electrons in the determined by three‐well potential mechanism of the second order ferroelectric phase transition at 337 K in Sn2P2S6crystals. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Half‐metallic ferrimagnet formed by substituting Fe for Mn in semiconductor MnTe
Authors: Zhu Li‐Fang , Liu Bang‐Gui
Published: December 2008

A ternary ferrimagnetic half‐metal, constructed through substituting 25% Fe for Mn in zincblende semiconductor MnTe, is predicted in terms of accurate first‐principles calculations. It has a large half‐metallic (HM) gap of 0.54 eV and its ferrimagnetic order is very stable against other magnetic fluctuations. The HM ferrimagnetism is formed because the complete moment compensation in the antiferromagnetic MnTe is replaced by an incomplete one in the Fe‐substituted MnTe. This should make a novel approach to new HM materials. The half‐metal could be fabricated because Fe has good affinity with Mn, and is useful for spintronics. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Band anti‐crossing and carrier recombination in dilute nitride phosphide based lasers and light emitting diodes
Authors: Chamings James , Ahmed Sucheta , Adams Alfred R. , Sweeney Stephen J. , Odnoblyudov Vladimir A. , Tu Charles W. , Kunert Bernardette , Stolz Wolfgang
Published: December 2008

We use high pressure techniques to investigate the properties of two classes of “dilute‐nitride‐phosphide”‐based devices; GaNP/GaP light emitting diodes for yellow–amber–red display applications and GaNAsP/GaP lasers, a potential route to producing lasers monolithically on silicon. Based upon high pressure electroluminescence measurements we find that the band anti‐crossing (BAC) model reasonably describes the GaN(As)P system based on an average of the nitrogen states. In terms of device characteristics, we find that carrier leakage into the X‐minima of GaP reduces the efficiency of GaNP/ GaP LEDs with increasing pressure. Lasing has been observed in GaNAsP/GaP devices with a pulsed threshold current density of 2.5 kA/cm2 at 80 K (λ = 890 nm). A weak increase in threshold current with hydrostatic pressure indicates that a carrier leakage path that does not involve the GaP X ‐minima is the dominant carrier recombination mechanism in these devices, in contrast to the LEDs. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Novel multi‐photon microscopy based on resonant nonlinear optics of colloidal quantum dots
Authors: Masia Francesco , Langbein Wolfgang , Borri Paola
Published: December 2008

We demonstrate a novel imaging modality based on the detection of resonant four‐wave mixing emitted by colloidal quantum dots. This third‐order signal is excited and detected at a visible wavelength in resonance with an electronic transition, and results in a significant improvement of the spatial resolution with respect to a twophoton fluorescence microscope.

In particular, we have investigated the dependence of the transient reduced absorption of the sample induced by the illumination (photobleaching) on the exposure time and excitation intensity, and its influence to the fourwave mixing signal (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conditional estimation of sensitivity and specificity from a phase 2 biomarker study allowing early termination for futility
Authors: Pepe Margaret Sullivan , Feng Ziding , Longton Gary , Koopmeiners Joseph
Published: December 2008

Development of a disease screening biomarker involves several phases. In phase 2 its sensitivity and specificity is compared with established thresholds for minimally acceptable performance. Since we anticipate that most candidate markers will not prove to be useful and availability of specimens and funding is limited, early termination of a study is appropriate, if accumulating data indicate that the marker is inadequate. Yet, for markers that complete phase 2, we seek estimates of sensitivity and specificity to proceed with the design of subsequent phase 3 studies. We suggest early stopping criteria and estimation procedures that adjust for bias caused by the early termination option. An important aspect of our approach is to focus on properties of estimates conditional on reaching full study enrollment. We propose the conditional‐UMVUE and contrast it with other estimates, including naïve estimators, the well‐studied unconditional‐UMVUE and the mean and median Whitehead‐adjusted estimators. The conditional‐UMVUE appears to be a very good choice. Copyright © 2008 John Wiley & Sons, Ltd.
On the pullback equation $(\varphi)^{*}(g)=f$
Authors: Bandyopadhyay S. , Dacorogna B.
Published: December 2008

We discuss the existence of a diffeomorphism

\varphi: \mathbb{R}^{n}\rightarrow \mathbb{R}^{n}

such that

\varphi ^{ \ast }(g) = f

where

f,g\::\mathbb{R}^{n}\rightarrow \Lambda ^{k}

are closed differential forms and

2⩽k⩽n

. Our main results (the case

k = n

having been handled by Moser [J. Moser, On the volume elements on a manifold, Trans. Amer. Math. Soc. 120 (1965) 286–294] and Dacorogna and Moser [B. Dacorogna, J. Moser, On a partial differential equation involving the Jacobian determinant, Ann. Inst. H. Poincaré Anal. Non Linéaire 7 (1990) 1–26]) are that

Nous montrons l'existence d'un difféomorphisme

\varphi \::\mathbb{R}^{n}\rightarrow \mathbb{R}^{n}

satisfaisant

\varphi ^{ \ast }(g) = f

où

f,g\::\mathbb{R}^{n}\rightarrow \Lambda ^{k}

sont des formes différentielles fermées et

2⩽k⩽n

. Nos résultats principaux (le cas

k = n

a été discuté notamment dans Moser [J. Moser, On the volume elements on a manifold, Trans. Amer. Math. Soc. 120 (1965) 286–294] et Dacorogna et Moser [B. Dacorogna, J. Moser, On a partial differential equation involving the Jacobian determinant, Ann. Inst. H. Poincaré Anal. Non Linéaire 7 (1990) 1–26]) sont les suivants.
Two solvable systems of coagulation equations with limited aggregations
Authors: Bertoin Jean
Published: December 2008

We consider two simple models for the formation of polymers where at the initial time, each monomer has a certain number of potential links (called arms in the text) that are consumed when aggregations occur. Loosely speaking, this imposes restrictions on the number of aggregations. The dynamics of concentrations are governed by modifications of Smoluchowski's coagulation equations. Applying classical techniques based on generating functions, resolution of quasi-linear PDE's, and Lagrange inversion formula, we obtain explicit solutions to these non-linear systems of ODE's. We also discuss the asymptotic behavior of the solutions and point at some connexions with certain known solutions to Smoluchowski's coagulation equations with additive or multiplicative kernels.
Existence and symmetry of least energy solutions for a class of quasi-linear elliptic equations
Authors: Jeanjean Louis , Squassina Marco
Published: December 2008

For a general class of autonomous quasi-linear elliptic equations on\mathbb{R}^{n}we prove the existence of a least energy solution and show that all least energy solutions do not change sign and are radially symmetric up to a translation in\mathbb{R}^{n}.

Pour une large classe d'équations quasilinéaires elliptiques autonomes sur\mathbb{R}^{N}, on montre l'existence d'une solution de moindre énergie. On montre aussi que toutes les solutions de moindres énergies ont un signe constant et sont, à une translation près, radiales.
Moving domain walls in magnetic nanowires
Authors: Kühn Katharina
Published: December 2008

This paper investigates the reversal of magnetic nanowires via a perturbation argument from the static case. We consider the gradient flow equation of the micromagnetic energy including the nonlocal stray field energy. For thin wires and weak external magnetic fields we show the existence of travelling wave solutions. These travelling waves are almost constant on the cross section and can thus be seen as moving domain walls of a type called transverse wall.

Cet article présente une étude du renversement des nano-fils magnétiques par une méthode de perturbation du cas statique. On considère l'équation du flot-gradient associé à l'énergie micromagnétique en incluant l'énergie de la perturbation non locale du champ magnétique. Pour des fils fins et des champs magnétiques externes de faible amplitude, on montre que les solutions prennent la forme d'ondes progressives. Ces ondes progressives ont une amplitude pratiquement homogène sur l'ensemble de la section, et peuvent donc être assimilées à des parois de domaines transverses.
On asymptotic stability in energy space of ground states of NLS in 2D
Authors: Cuccagna Scipio , Tarulli Mirko
Published: December 2008

We transpose work by K. Yajima and by T. Mizumachi to prove dispersive and smoothing estimates for dispersive solutions of the linearization at a ground state of a Nonlinear Schrödinger equation (NLS) in 2D. As an application we extend to dimension 2D a result on asymptotic stability of ground states of NLS proved in the literature for all dimensions different from 2.

On utilise les travaux de K. Yajima et T. Mizumachi pour prouver des estimations dispersives et régularisantes des solutions de l'équation linéarisée aux états fondamentaux de NLS in 2D. On applique ces résultats pour obtenir des extensions en dimension 2D de la stabilité asymptotique prouvée en littérature pour toutes les dimensions différentes de 2.
A high molecular weight polypeptide cross‐reacting with the antibodies to the dynein heavy chain localizes to the subset of Golgi complex in higher plant cells
Authors: Shanina Nina A. , Lazareva Elena M. , Skorova Ekaterina Y. , Chentsov Yuri S. , Smirnova Elena A.
Published: December 2008

Antibodies were produced against fragments of the microtubule‐binding domain and the motor domain of the dynein heavy chain from Dictyostelium discoideum to probe whole cell extracts of root meristem cells of wheat Triticum aestivum. In plant extracts, these antibodies cross‐reacted with a polypeptide of high molecular weight (>500 kDa). The antibodies bound to protein A‐Sepharose precipitated high molecular weight polypeptide from cell extracts. Immunofluorescence showed that the antibodies identified various aggregates inside cells, localized at the perinuclear area during interphase to early prophase, at the spindle periphery and polar area during mitosis, and in the interzonal region during phragmoplast development. Some aggregates were also co‐labeled by markers for the Golgi apparatus. Thus, we found in higher plant cells a high molecular weight antigen cross‐reacting with the antibodies to motor and microtubule‐binding domains of dynein heavy chains. This antigen is associated with aggregates distributed in the cytoplasm in cell cycle‐dependent manner. A subset of these aggregates belongs to the Golgi complex.