bluuebunny/crossref_metadata_2025_split huggingface dataset:
RF refocused echoes of J‐coupled spin systems: Effects on RARE‐based spectroscopic imaging
Authors: Mayer Dirk , Dreher Wolfgang , Leibfritz Dieter , Spielman Daniel M. 
Published: April 2007

AbstractA numerical simulation tool was developed to calculate the echo amplitudes of J‐coupled resonances within a series of radiofrequency (RF) refocused echoes. The signal modulation due to J‐coupling in rapid acquisition with relaxation enhancement (RARE) is suppressed only when the inverse of the pulse interval (τ) is large compared to both the chemical shift (CS) difference (Δδ) of the coupled spins and the coupling constant. In contrast, the echo amplitudes in ultrafast low‐flip‐angle RARE (U‐FLARE) oscillate around a quasi‐steady‐state value that is greater than zero (neglecting relaxation and diffusion) even when Δδ > 1/τ. The flip‐angle distribution over the measured slice caused by the use of Gaussian‐shape slice‐selective refocusing pulses further reduces the echo oscillations. When the pulse interval falls short of the fast pulse rate regime, spectroscopic U‐FLARE provides an improved spatial impulse response in the phase‐encoding (PE) direction compared to spectroscopic RARE. Magn Reson Med 57:967–971, 2007. © 2007 Wiley‐Liss, Inc.
Perfusion MRI with radial acquisition for arterial input function assessment
Authors: Kholmovski Eugene G. , DiBella Edward V.R. 
Published: April 2007

AbstractQuantification of myocardial perfusion critically depends on accurate arterial input function (AIF) and tissue enhancement curves (TECs). Except at low doses, the AIF is inaccurate because of the long saturation recovery time (SRT) of the pulse sequence. The choice of dose and SRT involves a trade‐off between the accuracy of the AIF and the signal‐to‐noise ratio (SNR) of the TEC. Recent methods to resolve this trade‐off are based on the acquisition of two data sets: one to accurately estimate the AIF, and one to find the high‐SNR TEC. With radial k‐space sampling, a set of images with varied SRTs can be reconstructed from the same data set, allowing an accurate assessment of the AIF and TECs, and their conversion to contrast agent (CA) concentration. This study demonstrates the feasibility of using a radial acquisition for quantitative myocardial perfusion imaging. Magn Reson Med 57:821–827, 2007. © 2007 Wiley‐Liss, Inc.
Carotid plaque classification: Defining the certainty with which plaque components can be differentiated
Authors: Ronen Raphael R. , Clarke Sharon E. , Hammond Robert R. , Rutt Brian K. 
Published: April 2007

AbstractMulticontrast‐weighted MRI has the potential to become a powerful tool for assessment of atherosclerotic plaque. However, similarities in MR properties across plaque components limit the certainty with which these components can be differentiated. An understanding of MRI's underlying limitations in distinguishing atherosclerotic plaque components, and optimization of key parameters (including the set of components investigated and contrast weightings used) are required. In this study we analyzed endarterectomy specimens using multicontrast MRI and compared the results with matching histological findings to determine the probability of error, an unbiased measure of the underlying error caused by similarity in the spectral characteristics of components. The total error was >40% when five distinct components were investigated, but this was halved when components with similar functions and intensities were grouped together. When three contrast weightings were used to view plaque, diffusion‐weighted imaging (DWI) proved valuable for separating hemorrhage from necrotic core, and “hemorrhage + necrotic” from “loose connective tissue + fibrous tissue.” A two‐way interaction between contrast weightings and components demonstrated that the value of a contrast can be exploited or marginalized depending on the choice of contrast weightings used. Magn Reson Med 57:874–880, 2007. © 2007 Wiley‐Liss, Inc.
Reduction of transmitter B1 inhomogeneity with transmit SENSE slice‐select pulses
Authors: Zhang Zhenghui , Yip Chun‐Yu , Grissom William , Noll Douglas C. , Boada Fernando E. , Stenger V. Andrew 
Published: April 2007

AbstractParallel transmitter techniques are a promising approach for reducing transmitter B1 inhomogeneity due to the potential for adjusting the spatial excitation profile with independent RF pulses. These techniques may be further improved with transmit sensitivity encoding (SENSE) methods because the sensitivity information in pulse design provides an excitation that is inherently compensated for transmitter B1 inhomogeneity. This paper presents a proof of this concept using transmit SENSE 3D tailored RF pulses designed for small flip angles. An eight‐channel receiver coil was used to mimic parallel transmission for brain imaging at 3T. The transmit SENSE pulses were based on the fast‐kz design and produced 5‐mm‐thick slices at a flip angle of 30° with only a 4.3‐ms pulse length. It was found that the transmit SENSE pulses produced more homogeneous images than those obtained from the complex sum of images from all receivers excited with a standard RF pulse. Magn Reson Med 57:842–847, 2007. © 2007 Wiley‐Liss, Inc.
MRI in mouse developmental biology
Authors: Turnbull Daniel H. , Mori Susumu 
Published: April 2007

AbstractMice are used in many studies to determine the role of genetic and molecular factors in mammalian development and human congenital diseases. MRI has emerged as a major method for analyzing mutant and transgenic phenotypes in developing mice, at both embryonic and neonatal stages. Progress in this area is reviewed, with emphasis on the use of MRI to analyze cardiovascular and neural development in mice. Comparisons are made with other imaging technologies, including optical and ultrasound imaging, discussing the potential strengths and weaknesses of MRI and identifying the future challenges for MRI in mouse developmental biology. Copyright © 2007 John Wiley & Sons, Ltd.
Oxidative stress and DNA hypermethylation status in renal cell carcinoma arising in patients on dialysis
Authors: Hori Y , Oda Y , Kiyoshima K , Yamada Y , Nakashima Y , Naito S , Tsuneyoshi M 
Published: April 2007

AbstractRenal cell carcinoma (RCC) is more frequently observed in patients on dialysis than in patients with normal renal function. However, the mechanism underlying carcinogenesis in RCC patients on dialysis is still unclear. We hypothesized that oxidative stress affects patients on dialysis and generates new neoplasms, and therefore analysed the correlation between the influences of various markers of oxidative stress and carcinogenesis in those patients. We evaluated the immunohistochemical expression of oxidative stress markers, such as iNOS, 8‐OHdG, and COX‐2 in 42 cases on dialysis and 51 cases with normal renal function as a control. The methylation status of p16INK4a, p14ARF, VHL, and RASSF1A was analysed together with clinicopathological factors. Histologically, the papillary type was observed more frequently in dialysis RCC than in sporadic RCC. Immunohistochemically, overexpression of iNOS (p < 0.0001) and COX‐2 (p = 0.0002) was more frequently observed in dialysis RCC. Furthermore, the 8‐OHdG labelling index was significantly higher in dialysis RCC than in sporadic RCC. Hypermethylation of p16INK4a was more frequently found in dialysis RCC (p < 0.05). However, no significant correlations between oxidative stress markers and DNA hypermethylation status were observed. The overexpression of iNOS, COX‐2, and 8‐OHdG in dialysis RCC suggests that patients on dialysis are affected by oxidative stress and that this effect plays an important role in the genesis of dialysis RCC. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
CNS complications in children receiving chemotherapy or hematopoietic stem cell transplantation: Retrospective analysis and clinical study of survivors
Authors: Schmidt Katrin , Schulz Ansgar Stephan , Debatin Klaus‐Michael , Friedrich Wilhelm , Classen Carl Friedrich 
Published: April 2007

AbstractBackgroundClinical studies analyzing CNS complications in pediatric oncology systematically are rare.ProcedureIn a single center retrospective analysis, CNS complications in 950 subsequent pediatric patients treated between 1992 and 2004 by chemotherapy or hematopoietic stem cell transplantation (HSCT) were studied. Forty‐six patients had pre‐existing CNS diseases and were excluded. Out of the 904 remaining, 76 (8.4%) had 82 CNS complications.ResultsThe most common manifestations were seizures (in 50.6% of the CNS episodes), altered states of consciousness, and motor deficits (in 47.5% of the episodes each). CNS complications were caused by infections (26.8%), toxicity (25.6%), neoplasma (13.4%), vascular (10.9%), and metabolic disturbances (8.5%). In 14.6%, the mechanism remained unclear. Patients (23.7%) died from the CNS event. Neoplastic disorders had the worst (50%) while metabolic the best (0% mortality) prognosis. Imaging techniques were the most effective diagnostic measures, followed by laboratory analysis, clinical examination, and CSF analysis. A neuro‐psychological (CBCL, CFT‐1/−20—testing) examination could be done in 21 of 32 long‐term survivors. Seven had a major, 3 minor neurological impairment, 11 were normal in all tests.ConclusionsThese data show that there is not one typical CNS complication, but a wide variety. There is no close connection between either underlying disease or symptoms and cause of the complication. Prognosis is variable. About two thirds of the long‐term survivors could lead a normal life. Pediatr Blood Cancer 2008;50:331–336. © 2007 Wiley‐Liss, Inc.
Prenatal detection of congenital bilateral cataract leading to the diagnosis of Nance‐Horan syndrome in the extended family
Authors: Reches Adi , Yaron Yuval , Burdon Kathryn , Crystal‐Shalit Ornit , Kidron Dvora , Malcov Mira , Tepper Ron 
Published: April 2007

AbstractObjectivesTo describe a family in which it was possible to perform prenatal diagnosis of Nance‐Horan Syndrome (NHS).MethodsThe fetus was evaluated by 2nd trimester ultrasound. The family underwent genetic counseling and ophthalmologic evaluation. The NHS gene was sequenced.ResultsUltrasound demonstrated fetal bilateral congenital cataract. Clinical evaluation revealed other family members with cataract, leading to the diagnosis of NHS in the family. Sequencing confirmed a frameshift mutation (3908del11bp) in the NHS gene.ConclusionEvaluation of prenatally diagnosed congenital cataract should include a multidisciplinary approach, combining experience and input from sonographer, clinical geneticist, ophthalmologist, and molecular geneticist Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and morphological characterization of poly(ϵ‐caprolactone) and poly(2‐methyloxazoline) substituted phenyl rings and phenylene oligomers
Authors: Levent Demirel A. , Yurteri Seda , Cianga Ioan , Yagci Yusuf 
Published: April 2007

AbstractPoly(ϵ‐caprolactone) (PCL) and poly(2‐methyloxazoline) (POx) substituted phenyl rings (macromonomers) and the corresponding substituted polyphenylene oligomers have been synthesized in various chemical structures. Macromonomers were synthesized by ring opening polymerization. Poly(phenylene) oligomers were then synthesized by cross‐coupling of the macromonomers in Ni‐catalyzed polycondensation reactions. The macromonomers and oligomers have been characterized by 1H‐NMR, IR, GPC, and DSC. The effect of side chain chemistry and architecture on the resulting morphology in thin films has been investigated by atomic force micro‐scopy and wide angle X‐ray scattering. Polyphenylene oligomers showed layered morphologies in thin films. The orientation of the layers depended on the chemistry of the side chains and the backbone architecture. Linear oligomers containing statistically distributed segments having POx or PCL side chains showed layers perpendicular to the underlying substrate. Attachment of polystyrene end block to PCL chain together with the meta‐connectivity of the backbone resulted in layers parallel to the substrate. Our results also indicate that substitution of polymeric chains to phenyl rings can induce ordered structures of macromonomers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2091–2104, 2007
Mechanical Properties of Thin Films and Nanometric Multilayers Using Tensile Testing and Synchrotron X‐Ray Diffraction
Authors: Le Bourhis Eric , Faurie Damien , Girault Baptiste , Goudeau Philippe , Renault Pierre‐Olivier , Villain Pascale , Badawi Frédéric 
Published: April 2007

AbstractX‐Ray diffraction (XRD) in combination with tensile testing is a very attractive tool for investigating the elastic behavior and further fracture or plasticity of metallic thin films and multilayers. Such studies are carried out with synchrotron X‐ray sources allowing for several diffraction and loading conditions to be investigated and hence for great precision to be achieved. XRD is phase selective and allows for the study of individual layers or phase contributions. The method is based on a length scale change to relate in‐grain elastic strains to tensile macro‐stresses. Hence, it requires the modeling of the grain interactions in view of the structure of the films (morphology, texture). The paper is illustrated with studies carried out on elastically isotropic tungsten (W) films, elastically anisotropic gold (Au) textured films, and nanometric tungsten/copper (W/Cu) multilayers.magnified image
Nitriding of Stainless Steel: PIII or Low Energy Nitriding?
Authors: Mändl Stephan 
Published: April 2007

AbstractBoth plasma immersion ion implantation (PIII) and low energy implantation (LEI) of nitrogen into austenitic stainless steel lead to the formation of a very hard and wear resistant surface layer, expanded austenite. Heat balance and particle flux measurements were performed and compared with simulations to obtain the global and local temperature variations as a function of the particle and heat flux. Comparing PIII and LEI within the same UHV vacuum system, and on the same substrate holder shows that similar diffusion, hardness and wear are observed; only the lattice expansion is larger for the case of PIII than for LEI.magnified image
Recent Advances in the Research on Non‐Equilibrium Atmospheric Pressure Plasma Jets
Authors: Laimer Johann , Störi Herbert 
Published: April 2007

AbstractRecently, there has been increased interest in using atmospheric pressure plasmas for materials processing, since these plasmas do not require expensive vacuum systems. However, APGDs face instabilities. Therefore, special plasma sources have been developed to overcome this obstacle, which make use of DC, pulsed DC and AC ranging from mains frequency to RF. Recently, the APPJ was introduced, which features an α‐mode of an RF discharge between two bare metallic electrodes. Basically, three different geometric configurations have been developed. A characterization of the APPJs and their applications is presented.magnified image
Surface Technology with Cold Microplasmas
Authors: Klages Claus‐Peter , Hinze Alena , Lachmann Kristina , Berger Claudia , Borris Jochen , Eichler Marko , von Hausen Margret , Zänker Antje , Thomas Michael 
Published: April 2007

AbstractVarious new plasma‐based surface technological processes are made feasible by localizing atmospheric‐pressure discharges to predefined volumes with sub‐millimeter linear dimensions. So‐called Plasma Printing processes use cold discharges in microcavities formed temporarily by contacting a substrate with a suitably designed kind of plasma stamp. Aside from dielectric barrier discharges driven by mid‐frequency (MF) AC voltages, cold microplasmas can also be sustained in arrangements without a dielectric barrier, if RF excitation is used. The modification or coating of internal surfaces in already sealed microfluidic systems promises the achievement of a wide range of physico‐chemical surface properties which are difficult to attain by wet‐chemical or low‐pressure plasma processes. Using a proper electrode arrangement, the coating or modification can be localized to a selected segment of a microfluidic system.magnified image
Materials Science and Technological Aspects of Electrospark Deposition of Nanostructured WC‐Co Coatings onto Titanium Substrates
Authors: Levashov Evgeny A. , Zamulaeva Evgenia I. , Kudryashov Alexander E. , Vakaev Peter V. , Petrzhik Mikhail I. , Sanz Alejandro 
Published: April 2007

AbstractThe composition and structure of coatings deposited with nano‐ and microstructured electrodes WC‐8% Co onto Ti substrates were characterized by XRD, XPS, EPMA, SEM, and SIM. Physical and chemical processes taking place at the contact surface of electrode and substrate during electrospark deposition are considered. Under optimized conditions (E = 0.13 J), deposition with a nanostructured electrodes provides fine‐grained coatings exhibiting higher hardness, improved wear resistance, and a lower friction coefficient (compared to VK8‐based coatings).magnified image
Similarities and Particularities of Low‐ and High‐Temperature Plasma Technologies
Authors: Schumacher Uwe 
Published: April 2007

AbstractAlthough plasmas cover an enormously wide range of parameters, and although the technologies and their applications differ strongly, several general mechanisms and technological processes, such as dimensionless parameters, generation and controlling of plasmas by particle wave interactions, plasma‐wall‐interactions, surface engineering and diagnostics are quite similar. Microwave technology offers both low temperature plasma applications and plasma heating for the fusion reactors. The interaction of plasmas with the nearby surfaces and the resulting material changes follow the same general mechanisms in low, as well as in high temperature plasmas, and their diagnostics are similar.magnified image
Macroscopic Description of Plasma Polymerization
Authors: Hegemann Dirk , Hossain Mohammad Mokbul , Körner Enrico , Balazs Dawn J. 
Published: April 2007

AbstractIndustrial applications based on plasma polymerization require reliable processes that can be transferred to production‐scale reactors. To enable an inexpensive access to control plasma deposition processes, macroscopic kinetics were investigated to describe plasma polymerization, which is based on the concept of chemical quasi‐equilibrium. The evaluation of deposition rates was carried out in order to obtain the apparent activation energy for a specific process. Influencing factors, such as substrate temperature, energetic particles, reactor geometry, plasma expansion, pressure, monomer, carrier/reactive gas, power modulation, and plasma source were thoroughly examined. The obtained activation energy was correlated to the plasma‐chemical processes, such as dissociation and radical formation, which are taking place within the active plasma zone. Since these processes are also contributing to the film growth, the activation energy was used for the scale‐up of plasma polymerization processes.magnified image
Regression analysis of censored survival data with the generalized F family—an alternative to the proportional hazards model
Authors: Ciampi Antonio , Hogg Sheilah A. , Kates Louis 
Published: April 2007

AbstractWe show that the generalized F family is a useful tool for regression analysis with censored survival data. We discuss maximum likelihood estimation and give asymptotic procedures for calculating confidence intervals, tests of significance for the parameters, life expectancy, quantiles and survival rates. Survival data on 704 ovarian carcinoma patients serve to demonstrate the utility of the model.
The use of logit models to investigate social and biological factors in infant mortality. IV: Post‐neonatal mortality
Authors: Machin D. , Murrells T. J. , Catford J. C. , Smith T. M. F. 
Published: April 2007

AbstractInfant mortality data for England and Wales, cross‐classified by mother's age, parity and social class have been published on two occasions, the first giving the relevant data for 1949/50, the second for 1975, some 25 years later. Published analyses of these separate data sets have been based on graphical and tabular analysis. This paper describes the application of logit models using the methodology presented by Murrells et al.1 to investigate post‐neonatal deaths.
Algorithm for the grouping of contiguous geographical zones
Authors: Huel Guy , Petiot Jean‐Francois , Lazar Philippe 
Published: April 2007

AbstractIn geographical epidemiology, the correlation between two variables is often studied, using as basic units those zones for which these variables are available. However, because of their geographical contiguity, it could be misleading to consider each of these zones as independent statistical units. Moreover, spatial distributions (either of the factor or of the disease) are often distributed in relatively simple patterns; these patterns may induce strong correlations. Thus, the general pattern of the spatial distribution of the variables should be investigated before any attempt to infer epidemiological interpretation of a relationship. This paper presents an algorithm to construct contiguous groupings which are similar enough with regard to one of the two variables considered and to thus divide the original set of geographical areas into contrasting zones. The algorithm is easy to compute and allows mapping of the geographical distribution of the variable studied. It also lessens the risk of duplication of basic information by reducing the autocorrelation of one of the variables.
Dose‐interpolation of immunoassay data: Uncertainties associated with curve‐fitting
Authors: Kay C. , Nix A. B. J. , Kemp K. W. , Rowlands R. J. , Richards G. , Groom G. V. , Griffiths K. , Wilson D. W. 
Published: April 2007

AbstractEstimates of analyte concentrations, obtained by immunoassay, have error distributions which are generally underestimated. Better estimates, which take into account the distribution of the response metameter of the calibration curve and uncertainties associated with the location of the fitted curve, have been obtained by computer simulation using practical immunoassay data. The increased use of curve‐fitting software in automated immunoassay equipment has prompted the investigation of reported analyte concentration distributions for three commonly used functions, namely the logit‐log, the 4‐parameter logistic and the fourparameter Amersham models. The simulation model is of potential value for a variety of situations.
Computer simulation of a clinical trial as an aid to teaching the concept of statistical significance
Authors: Bland J. M. 
Published: April 2007

AbstractThe advent of cheap and powerful microcomputers provides opportunities for improving the teaching of statistics in medicine. This paper describes a practical exercise in which students study the concept of statistical significance using a simple computer program which simulates a clinical trial. The students are required to make decisions about patients with incomplete data and form contingency tables for analysis. This includes analysing contingency tables with several cells having small expected frequencies. The results from 25 groups of students are collected together and presented to the class. Two null hypotheses are tested, one of which is true. For the true null hypothesis the group is likely to produce, by chance, at least one significant result at the 0.05 level. For the false null hypothesis only a minority of results will be significant, because the sample size is small. This leads to a discussion of the concept of statistical significance. The simulation model is described and the advantages and potential of this type of teaching are discussed.