bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimising reaction performance in the pharmaceutical industry by monitoring with NMR
Authors: Bernstein Michael A. , Štefinović Marijan , Sleigh Chris J. 
Published: May 2007

AbstractQuality assurance and process understanding are assuming increasing importance in the production of Active Pharmaceutical Ingredients (APIs). NMR has the potential to report on physical processes, quantities, structures, and speciation as chemical reactions progress. Following the progression of chemical reactions by placing the sample in an NMR tube, one can perform a large number of useful studies that provide chemical and mechanistic insight. But this simple approach can have limitations, and we have therefore constructed an apparatus comprising a laboratory reactor coupled with an NMR flow cell. The reactor duplicates the exact reaction conditions that will apply with large‐scale production. This reaction mixture is sampled and pumped to a high‐resolution NMR flow cell where the spectrum is recorded through the course of the reaction. We demonstrate the utility of reaction monitoring using NMR both for simple cases where tubes can be used, and describe the design of the on‐flow apparatus and highlight its utility with an example. Copyright © 2007 John Wiley & Sons, Ltd.
Chiral recognition of the Schiff bases by NMR spectroscopy in the presence of a chiral dirhodium complex. Deuterium isotope effect on 13C chemical shift of the optically active Schiff bases and their dirhodium adducts
Authors: Rozwadowski Z. 
Published: May 2007

AbstractThe dirhodium method has been successfully applied in chiral recognition of the optically active Schiff bases, derivatives of ortho‐hydroxyaldehydes existing in the NH‐form. or at tautomeric equilibrium. The position of the equilibrium of Schiff bases as well as their adducts has been established on the basis of measurements of deuterium isotope effects on 13C chemical shifts. The presence of the proton transfer equilibrium or NH‐tautomer has promoted the adduct formation. At the equilibrium state, formation of the adducts has shifted the proton transfer equilibrium towards the NH‐form. The binding site was the oxygen atom of the proton donor group. Copyright © 2007 John Wiley & Sons, Ltd.
Homonuclear long‐range correlation spectra from HMBC experiments by covariance processing
Authors: Schoefberger Wolfgang , Smrečki Vilko , Vikić‐Topić Dražen , Müller Norbert 
Published: May 2007

AbstractWe present a new application of covariance nuclear magnetic resonance processing based on 1H13C‐HMBC experiments which provides an effective way for establishing indirect 1H1H and 13C13C nuclear spin connectivity at natural isotope abundance. The method, which identifies correlated spin networks in terms of covariance between one‐dimensional traces from a single decoupled HMBC experiment, derives 13C13C as well as 1H1H spin connectivity maps from the two‐dimensional frequency domain heteronuclear long‐range correlation data matrix. The potential and limitations of this novel covariance NMR application are demonstrated on two compounds: eugenyl‐β‐D‐glucopyranoside and an emodin‐derivative. Copyright © 2007 John Wiley & Sons, Ltd.
In vitro comparison of the biological effects of three transfection methods for magnetically labeling mouse embryonic stem cells with ferumoxides
Authors: Suzuki Yoriyasu , Zhang Sally , Kundu Pratima , Yeung Alan C. , Robbins Robert C. , Yang Phillip C. 
Published: May 2007

AbstractIn vivo MRI of stem cells (SCs) is an emerging application to evaluate the role of cell therapy in restoring the injured myocardium. The high spatial and temporal resolution combined with iron‐oxide‐based intracellular labeling techniques will provide a sensitive, noninvasive, dual imaging modality for both cells and myocardium. In order to facilitate this novel imaging approach, much effort has been directed towards developing efficient transfection methods. While techniques utilizing poly‐L‐lysine (PLL), protamine sulfate (PS), and electroporation (ELP) have been proposed, the fundamental biological effects of these methods on mouse embryonic SCs (mESC) have not been investigated systematically. In this study a longitudinal in vitro evaluation of cellular viability, apoptosis, proliferation, and cardiac differentiation of magnetically labeled mESC was conducted. No significant difference was seen in these biological parameters among the three transfection methods. However, cardiac differentiation was most attenuated by ELP, and iron uptake was most effective by PS. Magn Reson Med 57:1173–1179, 2007. © 2007 Wiley‐Liss, Inc.
Short data‐acquisition times improve projection images of lung tissue
Authors: Kuethe Dean O. , Adolphi Natalie L. , Fukushima Eiichi 
Published: May 2007

AbstractMR images of laboratory rat lungs that resolve the thin membranes that separate lung lobes are presented. It appears that the capabilities of in vivo small‐animal pulmonary MRI may rival those of in vivo small‐animal X‐ray CT. Free induction decay (FID)‐projection imaging was employed with particular attention to the choice of acquisition time. For a given nominal resolution, one obtains optimal point discrimination when the acquisition timeTacqnormalized by the signal decay time constantTis approximately 0.8–0.9, although a better signal‐to‐noise ratio (SNR) is obtained when this quotient is 1.6. Currently available equipment should be able to even exceed the results presented herein. Magn Reson Med 57:1058–1064, 2007. © 2007 Wiley‐Liss, Inc.
In vivo differentiation of N‐acetyl aspartyl glutamate from N‐acetyl aspartate at 3 Tesla
Authors: Edden Richard A.E. , Pomper Martin G. , Barker Peter B. 
Published: May 2007

AbstractA method is described that allows the in vivo differentiation of N‐acetyl aspartate (NAA) from N‐acetyl aspartyl glutamate (NAAG) by in vivo MR spectroscopy (MRS) at 3 Tesla (3T). The method, which is based on MEGA‐point‐resolved spectroscopy (PRESS) editing, selectively targets the aspartyl spin system of one species while deliberately removing the other species from the spectrum. This allows quantitative measurements of NAA and NAAG without the need for fitting of unresolved peaks. White matter concentrations of NAA (6.7 ± 0.3 mM) and NAAG (2.2 ± 0.3 mM) were measured in 10 healthy volunteers to demonstrate the method. Magn Reson Med 57:977–982, 2007. © 2007 Wiley‐Liss, Inc.
Undersampled radial MRI with multiple coils. Iterative image reconstruction using a total variation constraint
Authors: Block Kai Tobias , Uecker Martin , Frahm Jens 
Published: May 2007

AbstractThe reconstruction of artifact‐free images from radially encoded MRI acquisitions poses a difficult task for undersampled data sets, that is for a much lower number of spokes in k‐space than data samples per spoke. Here, we developed an iterative reconstruction method for undersampled radial MRI which (i) is based on a nonlinear optimization, (ii) allows for the incorporation of prior knowledge with use of penalty functions, and (iii) deals with data from multiple coils. The procedure arises as a two‐step mechanism which first estimates the coil profiles and then renders a final image that complies with the actual observations. Prior knowledge is introduced by penalizing edges in coil profiles and by a total variation constraint for the final image. The latter condition leads to an effective suppression of undersampling (streaking) artifacts and further adds a certain degree of denoising. Apart from simulations, experimental results for a radial spin‐echo MRI sequence are presented for phantoms and human brain in vivo at 2.9 T using 24, 48, and 96 spokes with 256 data samples. In comparison to conventional reconstructions (regridding) the proposed method yielded visually improved image quality in all cases. Magn Reson Med 57:1086–1098, 2007. © 2007 Wiley‐Liss, Inc.
XTC MRI: Sensitivity improvement through parameter optimization
Authors: Ruppert Kai , Mata Jaime F. , Wang Hsuan‐Tsung J. , Tobias William A. , Cates Gordon D. , Brookeman James R. , Hagspiel Klaus D. , Mugler John P. 
Published: May 2007

AbstractXenon polarization Transfer Contrast (XTC) MRI pulse sequences permit the gas exchange of hyperpolarized xenon‐129 in the lung to be measured quantitatively. However, the pulse sequence parameter values employed in previously published work were determined empirically without considering the now‐known gas exchange rates and the underlying lung physiology. By using a theoretical model for the consumption of magnetization during data acquisition, the noise intensity in the computed gas‐phase depolarization maps was minimized as a function of the gas‐phase depolarization rate. With such optimization the theoretical model predicted an up to threefold improvement in precision. Experiments in rabbits demonstrated that for typical imaging parameter values the optimized XTC pulse sequence yielded a median noise intensity of only about 3% in the depolarization maps. Consequently, the reliable detection of variations in the average alveolar wall thickness of as little as 300 nm can be expected. This improvement in the precision of the XTC MRI technique should lead to a substantial increase in its sensitivity for detecting pathological changes in lung function. Magn Reson Med 57:1099–1109, 2007. © 2007 Wiley‐Liss, Inc.
Degenerate mode band‐pass birdcage coil for accelerated parallel excitation
Authors: Alagappan Vijayanand , Nistler Juergen , Adalsteinsson Elfar , Setsompop Kawin , Fontius Ulrich , Zelinski Adam , Vester Markus , Wiggins Graham C. , Hebrank Franz , Renz Wolfgang , Schmitt Franz , Wald Lawrence L. 
Published: May 2007

AbstractAn eight‐rung, 3T degenerate birdcage coil (DBC) was constructed and evaluated for accelerated parallel excitation of the head with eight independent excitation channels. Two mode configurations were tested. In the first, each of the eight loops formed by the birdcage was individually excited, producing an excitation pattern similar to a loop coil array. In the second configuration a Butler matrix transformed this “loop coil” basis set into a basis set representing the orthogonal modes of the birdcage coil. In this case the rung currents vary sinusoidally around the coil and only four of the eight modes have significant excitation capability (the other four produce anticircularly polarized (ACP) fields). The lowest useful mode produces the familiar uniform B1 field pattern, and the higher‐order modes produce center magnitude nulls and azimuthal phase variations. The measured magnitude and phase excitation profiles of the individual modes were used to generate one‐, four‐, six‐, and eightfold‐accelerated spatially tailored RF excitations with 2D and 3D k‐space excitation trajectories. Transmit accelerations of up to six‐fold were possible with acceptable levels of spatial artifact. The orthogonal basis set provided by the Butler matrix was found to be advantageous when an orthogonal subset of these modes was used to mitigate B1 transmit inhomogeneities using parallel excitation. Magn Reson Med 57:1148–1158, 2007. © 2007 Wiley‐Liss, Inc.
Finite elements for elasticity with microstructure and gradient elasticity
Authors: Zervos A. 
Published: May 2007

AbstractWe present a general finite element discretization of Mindlin's elasticity with microstructure. A total of 12 isoparametric elements are developed and presented, six for plane strain conditions and six for the general case of three‐dimensional deformation. All elements interpolate both the displacement and microdeformation fields. The minimum order of integration is determined for each element, and they are all shown to pass the single‐element test and the patch test. Numerical results for the benchmark problem of one‐dimensional deformation show good convergence to the closed‐form solution. The behaviour of all elements is also examined at the limiting case of vanishing relative deformation, where elasticity with microstructure degenerates to gradient elasticity. An appropriate parameter selection that enforces this degeneration in an approximate manner is presented, and numerical results are shown to provide good approximation to the respective displacements and strains of a gradient elastic solid. Copyright © 2007 John Wiley & Sons, Ltd.
The social security earnings test and work incentives
Authors: Benítez‐Silva Hugo , Heiland Frank 
Published: May 2007

AbstractThe labor supply and benefit claiming incentives provided by the early retirement rules of the Social Security Old Age benefits program are of growing importance as the Normal Retirement Age (NRA) increases to 67, the labor force participation of Older Americans rises, and a variety of reforms to the Social Security system are considered. Any reform needs to take into account the effects and rationale of the Social Security Earnings Test and the Actuarial Adjustment Factor, which are likely to be widely misunderstood due to the relatively little attention paid by policymakers and researchers to the fact that Americans are willing to work while receiving benefits. We describe these incentives and emphasize that individuals who claim benefits before the NRA but continue to work, or return to the labor force, can reduce the early retirement penalty by suspending the collection of monthly benefits if they earn above the Earnings Test limit. We then argue that the Earnings Test can be distortionary and is costly to administer, and that these characteristics are inflated by the lack of information given to Older Americans regarding the consequences of working while receiving retirement benefits. We present results from statistical models of labor force exit behavior using data from the Health and Retirement Study showing the relevance of these incentives, and investigate the importance of informational asymmetries among beneficiaries regarding benefit withholding using a dynamic life‐cycle model of labor supply and benefit claiming. We then use the latter framework to compare the behavioral and welfare implications of a removal of the Earnings Test to the policy of providing more information regarding the Earnings Test and the adjustment of the rate of benefit pay to Older Americans. © 2007 by the Association for Public Policy Analysis and Management
The performance of charter schools in Wisconsin
Authors: Witte John , Weimer David , Shober Arnold , Schlomer Paul 
Published: May 2007

AbstractHow have charter schools in Wisconsin performed relative to traditional public schools? Two analyses provide an answer: First, a comparison of achievement test scores for students in Milwaukee charter and traditional schools from 1998 to 2002 for grades 3 through 10 finds a relative advantage for charter school students using fixed effects and first difference specifications. Second, a methodological approach new to the debate over performance in choice schools assesses schoollevel standardized tests in the fourth and eighth grades for 2000–01 and 2001–02. The results for fourth grade are generally favorable for charter schools; those for eighth grade are mixed. Overall, the results from these two analyses suggest that charter schools in Wisconsin are performing somewhat better than the traditional public schools from which they draw students. © 2007 by the Association for Public Policy Analysis and Management
Income tax policy and charitable giving
Authors: Brooks Arthur C. 
Published: May 2007

AbstractMany studies over the past 20 years have looked at the response of charitable donations to tax incentives—the tax price elasticity of giving. Generally, authors have assumed this elasticity is constant across all types of giving. Using the 2001 Panel Study of Income Dynamics data on charitable giving, this paper estimates the tax price elasticity across six nonprofit subsectors, finding substantial variation. These results suggest that the fiscal effectiveness of tax deductibility depends on the type of donation involved. This has implications for both public policy and nonprofit management. © 2007 by the Association for Public Policy Analysis and Management
Disproportionate representation of KRAS gene mutation in atypical adenomatous hyperplasia, but even distribution of EGFR gene mutation from preinvasive to invasive adenocarcinomas
Authors: Sakamoto H , Shimizu J , Horio Y , Ueda R , Takahashi T , Mitsudomi T , Yatabe Y 
Published: May 2007

AbstractIn the resected lung, additional small lesions are occasionally found incidentally, and include the full spectrum of preinvasive to invasive lesions under the current putative schema of the sequential development of lung cancer. In this study, we examined EGFR and KRAS gene mutations in 119 synchronous pulmonary lesions, including 40 precursor lesions (atypical adenomatous hyperplasia, AAH), 26 carcinomas in situ (non‐mucinous bronchioloalveolar carcinoma, BAC), 14 minimally invasive adenocarcinomas, 34 overt invasive adenocarcinomas, and five of other subtypes of cancer. Although the mutually exclusive nature of KRAS and EGFR gene mutations was maintained even in preinvasive lesions, the incidences of the lesions along the putative progression schema were quite different. The KRAS gene was mutated in 33% of AAH, 12% of carcinomas in situ, 8% of minimally invasive adenocarcinomas and 0% of well‐differentiated adenocarcinomas, whereas the frequencies of EGFR mutation did not fluctuate greatly, at 25%, 51%, 36%, 86% and 67%, respectively. These results are consistent with the findings of a published gene‐targeted mouse model; the mice expressing oncogenic KRAS developed AAH but not invasive adenocarcinoma, whereas a spectrum of preinvasive to invasive adenocarcinomas was observed in the mice expressing mutant EGFR. Taking these factors together, it is suggested that AAH could develop by either KRAS or EGFR gene mutation, but AAH harbouring a KRAS gene mutation might not progress further to an invasive cancer. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Characterisation of fungal lanostane‐type triterpene acids by electrospray ionisation mass spectrometry
Authors: Cabrera Gabriela M. , Vellasco Adriana P. , Levy Laura M. , Eberlin Marcos N. 
Published: May 2007

AbstractLanostane‐triterpene acids obtained from the culture of the fungus Coriolellus malicola were studied by electrospray mass spectrometry in the negative ion mode using quadrupole time‐of‐flight and quadrupole ion trap analysers. Despite the differences observed in the mass spectra recorded with these instruments, a set of fragment ions was found to be characteristic of the family, depending on the Δ7,9(11) or Δ8 skeleton and the particular functional group at C‐3. Copyright © 2007 John Wiley & Sons, Ltd.
Genetic and alkaloid analysis of Menispermum Dauricum DC. by RAPD and HPLC
Authors: Zhou Jue , Qu Fan , Nan Rui 
Published: May 2007

AbstractThe aim of the present work was to determine whether dauricine could be used as a taxonomic marker for Menispermum dauricum DC., and to explore the correlation among RAPD, ecological markers and chemical markers. To this end, the chemical and genetic differences of 173 individual samples of M. dauricum from nine different sources were studied based on the relevant ecological factors including longitude, latitude, annual precipitation, mean temperature, annual accumulated temperature and mean sea level. The contents of dauricine in the sample rhizomes were assayed by HPLC with photodiode array detection. The leaves from the same sample were assayed using randomly amplified polymorphism DNA (RAPD). The genetic distances were then compared. Hierarchical cluster analysis and multiple linear stepwise regression analysis were used in the statistical analysis. The results indicated that the contents of dauricine were respectively correlated with the genetic distance (r = 1.000), longitude (r = 0.849), latitude (r = 0.861), annual precipitation (r = 0.903), mean temperature(r = 0.912), annual accumulated temperature (r = 0.919) and mean sea level (r = 0.925). It is concluded that the content of dauricine in M. dauricum is significantly correlated with genetic distance and ecological factors, and may be used as the taxonomic marker. Copyright © 2007 John Wiley & Sons, Ltd.
High‐performance liquid chromatography with atmospheric pressure chemical ionization and electrospray ionization mass spectrometry for analysis of Angelica sinensis
Authors: Wang Ya‐Li , Liang Yi‐Zeng , Chen Ben‐Mei 
Published: May 2007

AbstractAn HPLC‐PAD‐API/MS method for analysing the chemical constituents of Angelica sinensis (A. sinensis) has been developed. ESI and APCI spectra, in both positive ion (PI) and negative ion (NI) modes, provided very useful information concerning the molecular weights of detected compounds. By comparing the retention times, UV spectra, mass spectra and molecular weights of detected compounds with those published in literature, 15 constituents of A. sinensis could be tentatively identified. This technique involving combined MS information may provide an objective, reliable and rapid analytical method for the quality control and database research of traditional Chinese medicines. Copyright © 2007 John Wiley & Sons, Ltd.
A clinical algorithm of prenatal diagnosis of Radial Ray Defects with two and three dimensional ultrasound
Authors: Kennelly Máiréad M. , Moran Paul 
Published: May 2007

AbstractObjectiveTo review the antenatal diagnosis of Radial Ray Defects (RRD) in a tertiary referral fetal medicine unit & to set out a clinical algorithm to aid assessment and management.MethodsAll cases of RRD isolated or associated with other anomalies notified to NorCAS between 2000 and 2005 were identified. Outcome information was obtained from paediatric records and histopathology and cytogenetics in cases of pregnancy interruption.ResultsThirty five cases were referred, 17 cases were excluded including skeletal dysplasia (16). An antenatal diagnosis was made in 61% (11/18) ‐ isolated limb reduction defects, Trisomy 18, TAR, fetal valproate syndrome, Roberts syndrome. Of the rest, 3 had a cordocentesis with normal chromosome fragility tests (VACTERL association, Goldenhar syndrome and Acrofacial dysostosis) and 4 declined testing (2 TOP with Cornelia de Lange, 2 ongoing pregnancies diagnosed postpartum with Fanconi anaemia and VACTERL association).ConclusionsThe challenge of radial ray anomalies is to combine clinical and ultrasound expertise with input from clinical genetics, ultrasound and molecular testing. Our clinical algorithm encourages targeted sonography including 3D views for subtle face, ear and hand anomalies, providing a useful tool to diagnose the underlying condition, crucial for appropriate obstetric management and prognosticating for future pregnancies. Copyright © 2007 John Wiley & Sons, Ltd.