bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rhodium(I) Complexes Containing β‐Amino Alcohol and 1,2‐Diamine Ligands: Syntheses, Structures, and Catalytic Applications
Authors: Dahlenburg Lutz , Treffert Harald , Farr Christian , Heinemann Frank W. , Zahl Achim 
Published: March 2007

AbstractThe bridge‐opening reaction of [(η4‐C8H12)2Rh2(μ‐Cl)2] with chiral and achiral β‐amino alcohol nucleophiles gave mononuclear complexes [(η4‐C8H12)RhCl{HN(R)∩OH‐κN}] containing the amino alcohol ligands in N‐monodentate coordination; HN(R)∩OH = ethanolamine (4), 2‐amino‐2‐methyl‐1‐propanol (5), and either enantiomer of (R)‐, (S)‐2‐amino‐3‐methyl‐1‐butanol (D‐, L‐valinol) [(R)‐6, (S)‐6], (R)‐, (S)‐2‐pyrrolidinemethanol (D‐, L‐prolinol) [(R)‐7, (S)‐7], (1S,2R)‐, (1R,2S)‐2‐amino‐1‐phenyl‐1‐propanol (D‐, L‐norephedrine) [(1S,2R)‐8, (1R,2S)‐8], and (1S,2R)‐, (1R,2S)‐cis‐1‐amino‐2‐indanol [(1S,2R)‐9, (1R,2S)‐9]. Coordination of the free hydroxy function of the N,O ligands was brought about by both dehydrochlorination, which furnished the neutral valinolato chelate complex [(η4‐C8H12)Rh{(S)‐H2NCH(CHMe2)CH2O‐κN,κO}], (S)‐10, and by precipitation of the metal‐bound chloride with TlO3SCF3 to produce ionic chelate complexes [(η4‐C8H12)Rh{HN(R)∩OH‐κN,κO}]O3SCF3; HN(R)∩OH = 2‐amino‐2‐methyl‐1‐propanol (11), (S)‐2‐amino‐3‐methyl‐1‐butanol [(S)‐12], (S)‐2‐pyrrolidinemethanol [(S)‐13], (1R,2S)‐2‐amino‐1‐phenyl‐1‐propanol [(1R,2S)‐14], and (1R,2S)‐cis‐1‐amino‐2‐indanol [(1R,2S)‐15]. Except for only two in situ characterized [{(R)‐binap}Rh(H2N∩OH‐κN,κO)]+ cations, where H2N∩OH = L‐valinol or L‐norephedrine, no compound containing the various N,O ligands in addition to mono‐ or bidentate phosphanes could be prepared. In contrast, theP2/N2‐coordinated chelate complexes [{(R)‐binap}Rh(H2N∩NH2)]BF4 with H2N∩NH2 = H2NCMe2CMe2NH2 [(R)‐(16)], (R,R)‐H2NCH(Ph)CH(Ph)NH2 [(R),(R,R)‐17], and (R,R)‐1,2‐(H2N)2C6H10 [(R),(R,R)‐18] were easily obtained from [(η4‐C8H12)Rh{(R)‐binap}]BF4 and 1,2‐diamines. Oxidative addition of HCl to (R),(R,R)‐17 produced trans‐[{(R)‐binap}Rh(H)(Cl){(R,R)‐H2NCH(Ph)CH(Ph)NH2}]BF4 [(R),(R,R)‐19]. If activated by strong base (KOH), (R),(R,R)‐17 and (R),(R,R)‐19 acted as moderately active and enantioselective catalysts for the reduction of acetophenone by both direct and transfer hydrogenation: eemax: 71 % (S). The crystal structures of 4, (S)‐6, (R)‐7, (1R,2S)‐8, (S)‐10, (1R,2S)‐14, (1R,2S)‐15, (R)‐16, (R),(R,R)‐17, and two alcohol/alcoholato addition compounds, [(η4‐C8H12)Rh(H2NCMe2CH2O‐κN,κO)][(η4‐C8H12)Rh(H2NCMe2CH2OH‐κN,κO)][(η4‐C8H12)RhCl2] [1·2], and [(η4‐C8H12)Rh(H2NCMe2CH2O‐κN,κO)][(η4‐C8H12)Rh(H2NCMe2CH2OH‐κN,κO)]Cl [1·3], were determined. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Effect of CyDye minimum labeling in differential gel electrophoresis on the reliability of protein identification
Authors: Hrebicek Thomas , Dürrschmid Karin , Auer Norbert , Bayer Karl , Rizzi Andreas 
Published: March 2007

AbstractDifferential 2‐DE (DIGE) is a widely applied tool for the quantitative analysis of differentially represented proteins. The method involves covalent minimal labeling of proteins prior to their electrophoretic separation using CyDye™ DIGE Fluor minimal dyes. This methodology creates two different species per protein, the labeled (approx. 1–2%) and unlabeled (approx. 98–99%) ones, which differ in their molecular masses by 434–464 Da, depending on the attached dye. DIGE followed by automated spot picking according to the CyDye coordinates misses in many instances the exact positions where the maximum amounts of the considered proteins are located. This fact leads to a loss in sensitivity of the subsequent MALDI‐MS analyses and results in a reduced reliability of protein identification and sequence coverage. In this paper, the migration differences of labeled and unlabeled species are quantified together with the impact of this effect on the certainty of protein identification and sequence coverage investigating proteins up to 90 kDa.
Probabilistic estimation of maximum inelastic displacement demands for performance‐based design
Authors: Ruiz‐García Jorge , Miranda Eduardo 
Published: March 2007

AbstractA probabilistic approach to estimate maximum inelastic displacement demands of single‐degree‐of‐freedom (SDOF) systems is presented. By making use of the probability of exceedance of maximum inelastic displacement demands for given maximum elastic spectral displacement and the mean annual frequency of exceedance of elastic spectral ordinates, a simplified procedure is proposed to estimate mean annual frequencies of exceedance of maximum inelastic displacement demands. Simplifying assumptions are thoroughly examined and discussed. Using readily available elastic seismic hazard curves the procedure can be used to compute maximum inelastic displacement seismic hazard curves and uniform hazard spectra of maximum inelastic displacement demands. The resulting maximum inelastic displacement demand spectra provide a more rational way of establishing seismic demands for new and existing structures when performance‐based approaches are used. The proposed procedure is illustrated for elastoplastic SDOF systems having known‐lateral strength located in a region of high seismicity in California. Copyright © 2007 John Wiley & Sons, Ltd.
On dichotomizing phenotypes in family‐based association tests: quantitative phenotypes are not always the optimal choice
Authors: Fardo David , Celedón Juan C. , Raby Benjamin A. , Weiss Scott T. , Lange Christoph 
Published: March 2007

AbstractIn family‐based association studies, quantitative traits are thought to provide higher statistical power than dichotomous traits. Consequently, it is standard practice to collect quantitative traits and to analyze them as such. However, in many situations, continuous measurements are more difficult to obtain and/or need to be adjusted for other factors/confounding variables which also have to be measured. In such scenarios, it can be advantageous to record and analyze a “simplified/dichotomized” version of the original trait. Under fairly general circumstances, we derive here rules for the dichotomization of quantitative traits that maintain power levels that are comparable to the analysis of the original quantitative trait. Using simulation studies, we show that the proposed rules are robust against phenotypic misclassification, making them an ideal tool for inexpensive phenotyping in large‐scale studies. The guidelines are illustrated by an application to an asthma study. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
An open trial of aripiprazole augmentation for SSRI non‐remitters with late‐life depression
Authors: Rutherford Bret , Sneed Joel , Miyazaki Marissa , Eisenstadt Rachel , Devanand Devangere , Sackeim Harold , Roose Steven 
Published: March 2007

AbstractObjectiveTo evaluate the efficacy and tolerability of aripiprazole augmentation in elderly depressed patients who did not reach remission after treatment with an SSRI.MethodOutpatients 50 years and older with major depressive disorder not remitting after adequate treatment with an SSRI were eligible for the study. In the 6‐week long augmentation phase, antidepressants were continued without change and aripiprazole was titrated if needed to a maximum dose of 15 mg per day. Patients were evaluated at the study endpoint on an intent to treat basis, and the primary outcome measure was remission of depression as measured by Hamilton Rating Scale for Depression (HRSD) ≤ 10.ResultsTwenty patients having mean age 63.0 ± 9.6 years old, HRSD 20.0 ± 4.2, Beck Depression Inventory (BDI) 21.0 ± 9.8, Clinical Global Impression—Severity (CGI—S) 3.7 ± 0.9, and Mini Mental State Examination (MMSE) 29.2 ± 1.0 entered the study. At the study endpoint, mean HRSD was 7.6 ± 5.9, BDI 9.1 ± 9.3, and CGI—S 1.9 ± 1.1. A 50% remission rate of depression was observed after six weeks of augmentation with aripiprazole. Twenty five percent of subjects did not complete the study. The most frequent side effects observed were dry mouth (25%), agitation/anxiety (20%), and drowsiness (15%).ConclusionIn this study 50% of depressed patients not remitting after an adequate trial of an SSRI achieved a final HRSD ≤ 10 when given aripiprazole augmentation. Open trials such as this require follow up in a randomized, placebo‐controlled trial. Copyright © 2007 John Wiley & Sons, Ltd.
Northern Lights, Canada's version of the UNCITRAL Model Law on Cross‐Border Insolvency
Authors: Sarra Janis 
Published: March 2007

AbstractStatute of Canada Chapter 47, when it is proclaimed in force, will largely adopt the UNCITRAL Model Law on Cross‐border Insolvency. The current and proposed cross‐border provisions could be considered Canada's “Northern Lights”, evolving constantly, but aligning with the objectives and scope of the UNCITRAL Model Law. While Chapter 47 is a modified version of the Model Law, it continues Canada's regime as one of modified universalism, with a strong commitment to comity and coordination. There are likely to be contests for control over the scope of foreign proceedings, although arguably, no more so than under the language of the Model Law. The most critical issues to resolve in the short term are definitions of COMI where corporate groups are involved, and the issue of the scope and extent of possible concurrent main proceedings, both areas left to the discretion of the courts in their interpretation of the legislation's domestic, as well as cross‐border, provisions. Copyright © 2007 John Wiley & Sons, Ltd.
Origin of intrinsic 310‐helix versus strand stability in homopolypeptides and its implications for the accuracy of the Amber force field
Authors: Jagielska Anna , Skolnick Jeffrey 
Published: March 2007

AbstractCurrent all‐atom force fields often fail to recognize the native structure of a protein as the lowest free energy minimum. One possible cause could be the mathematical form of the potential based on the assumption that the conformation of a residue is independent of its neighbors. Here, using quantum mechanical (QM) methods (MP2/6‐31g**//HF/6‐31g** and MP2/cc‐pVDZ//cc‐pVDZ//HF/cc‐pVDZ), the intrinsic correctness of the gas phase terms (without solvation) of the Amber ff03 and ff99 potentials are examined by testing their ability to reproduce the relative 310‐helix versus extended structure stabilities in the gas phase for 1–7‐residue alanine, valine, leucine, and isoleucine homopolypeptides. The 310‐helix versus extended state stability strongly depends on chain length and less on the amino acid identity. The helical conformation becomes lower in energy than the extended conformation for all tested peptides longer than two residues, and its stability increases with the increase of chain length. The ff03 potential better describes the 310‐helix versus extended state energy than ff99 and also reproduces the curvature of the relative helix‐extended state energies. Therefore, the mathematical form of the Amber potential is sufficient to describe the local effect of 310‐helix versus extended structure stabilization in the gas phase. However, the energy curves are shifted and the backbone geometries differ compared with the QM results. This may cause significant geometric discrepancies between native and predicted structures. Therefore, extant molecular mechanics force fields, such as Amber, need refinement of their parameters to correctly describe helix‐extended state energetics and geometry of major conformations. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
A parallel distributed data CPHF algorithm for analytic Hessians
Authors: Alexeev Yuri , Schmidt Michael W. , Windus Theresa L. , Gordon Mark S. 
Published: March 2007

AbstractOne of the most commonly used means to characterize potential energy surfaces of reactions and chemical systems is the Hessian calculation, whose analytic evaluation is computationally and memory demanding. A new scalable distributed data analytic Hessian algorithm is presented. Features of the distributed data parallel coupled perturbed Hartree‐Fock (CPHF) are (a) columns of density‐like and Fock‐like matrices are distributed among processors, (b) an efficient static load balancing scheme achieves good work load distribution among the processors, (c) network communication time is minimized, and (d) numerous performance improvements in analytic Hessian steps are made. As a result, the new code has good performance which is demonstrated on large biological systems. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Chemical graph theory andn‐center electron delocalization indices: A study on polycyclic aromatic hydrocarbons
Authors: Mandado Marcos , González‐Moa María J. , Mosquera Ricardo A. 
Published: March 2007

AbstractRelations between aromaticity indices derived from chemical graph theory and those based on 6‐center electron delocalization are investigated for a series of polybenzenoid hydrocarbons. Aromatic stabilization obtained by means of the effective scaled electron delocalization is highly correlated to the resonance energy, RE, obtained both from SCF MO calculations and conjugated ring circuits model. Local aromaticity of benzene rings is discussed using two different criteria, in one of them aromaticity is just given by the cyclicπ‐electron conjugation of the ring, whereas terms involving more than one ring are also considered in the other one. Indices derived from chemical graph theory and those obtained from the 6‐center electron delocalization give rise to the same local aromaticity. Moreover, 6‐center electron delocalization provides more quantitative information. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Characterization of conformational equilibria through Hamiltonian and temperature replica‐exchange simulations: Assessing entropic and environmental effects
Authors: Faraldo‐Gómez José D. , Roux Benoît 
Published: March 2007

AbstractMolecular dynamics simulations based on the replica‐exchange framework (REMD) are emerging as a useful tool to characterize the conformational variability that is intrinsic to most chemical and biological systems. In this work, it is shown that a simple extension of the replica‐exchange method, known as Hamiltonian REMD, greatly facilitates the characterization of conformational equilibria across large energetic barriers, or in the presence of substantial entropic effects, overcoming some of the difficulties of REMD based on temperature alone. In particular, a comparative assessment of the HREMD and TREMD approaches was made, through computation of the gas‐phase free‐energy difference between the so‐called D2d and S4 states of tetrabutylammonium (TBA), an ionic compound of frequently used in biophysical studies of ion channels. Taking advantage of the greater efficiency of the HREMD scheme, the conformational equilibrium of TBA was characterized in a variety of conditions. Simulation of the gas‐phase equilibrium in the 100–300 K range allowed us to compute the entropy difference between these states as well as to describe its temperature dependence. Through HREMD simulations of TBA in a water droplet, the effect of solvation on the conformational equilibrium was determined. Finally, the equilibrium of TBA in the context of a simplified model of the binding cavity of the KcsA potassium channel was simulated, and density maps for D2d and S4 states analogous to those derived from X‐ray crystallography were constructed. Overall, this work illustrates the potential of the HREMD approach in the context of computational drug design, ligand‐receptor structural prediction and more generally, molecular recognition, where one of the most challenging issues remains to account for conformational flexibility as well for the solvation and entropic effects thereon. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Maximization of contrast‐to‐noise ratio to distinguish diffusion and microcirculatory flow
Authors: Maki Jeffrey H. , Benveniste Helene , MacFall James R. , Johnson G. Allan 
Published: March 2007

AbstractOptimization of the contrast‐to‐noise ratio (CNR) is described for microcirculation magnetic resonance (MR) imaging techniques based on flow‐compensated/flow‐dephased sequences, both with and without even‐echo rephasing. The authors present the most advantageous manner of applying flow‐dephased gradients, such that de‐phasing is maximal while diffusion losses are minimal. The theoretical considerations include phase, diffusion, echo time, and bandwidth in the determination of the optimal parameters for microcirculation imaging. Studies in phantoms consisting of stationary and flowing copper sul‐fate in Sephadex columns demonstrate the validity of the calculations. Optimized in vivo images of a rat stroke model demonstrate the potential of the flow‐compensated/flow‐dephased technique and the importance of optimizing CNR.
Phase III clinical evaluation of Gd‐HP‐DO3A in head and spine disease
Authors: Runge Val M. , Dean Bruce , Lee Charles , Carolan Fred , Heard Gene 
Published: March 2007

AbstractAs part of a phase III clinical trial, 25 patients with suspected intracranial or spinal disease underwent magnetic resonance (MR) imaging before and after intravenous injection of 0.1 mmol/ kg Gd‐HP‐DO3A (1,4,7‐tris[carboxymethy1]‐10‐[2′hydroxypropy1]‐1,4,7,10‐tetraazacyclodode‐cane), a neutral (nonionic) gadolinium chelate. Laboratory analysis included a complete blood count; blood chemistry; measurement of electrolyte levels; hepatic function, clotting function, and iron metabolism panels; and urinalysis both before and 24 hours after contrast agent administration. No statistically significant changes related to contrast agent administration were noted in laboratory values after administration of the contrast agent. In this selected group of patients, the contrast agent‐enhanced study provided greater diagnostic information than did the precontrast study in 69% of head cases and 67% of spine cases. These initial clinical trials demonstrate that Gd‐HP‐DO3A is a safe, efficacious agent for head and spine examinations.
Meningeal mesenchymal chondrosarcoma of the spine: A case report
Authors: Huckabee Rife E. 
Published: March 2007

AbstractPrimary soft‐tissue chondro‐sarcomas are most often of the mesenchymal variety. When affecting the central nervous system, these tumors usually arise from the intracranial meninges. Intraspinal meningeal lesions are much less common but may be considered, especially in the pediatric age group, when clinical or radiologic presentation is atypical. The author presents a case report including MR imaging studies of a 7‐year‐old girl with intraspinal dural chon‐drosarcoma.
Policies, guidelines, and recommendations for MR imaging safety and patient management
Authors: Shellock Frank G. ,   SMRI Safety Committee
Published: March 2007

AbstractThe following are policies, guidelines, and recommendations from the Safety Committee of the Society for Magnetic Resonance Imaging (SMRI) concerning various issues related to magnetic resonance (MR) imaging safety and patient management. These policies, guidelines, and recommendations were developed to provide standardized and consistent information for use by health practitioners involved in clinical MR imaging.
Comparing the FAISE method with conventional dual‐echo sequences
Authors: Melki Philippe S. , Mulkern Robert V. , Panych Lawrence P. , Jolesz Ferenc A. 
Published: March 2007

AbstractThe FAISE (fast‐acquisition interleaved spin‐echo) technique consists of a hybrid rapid‐acquisition relaxation‐enhanced (RARE) sequence combined with a specific phase‐encode reordering method. Implemented on a 1.5‐T unit, this multisection, high‐resolution technique permits convenient contrast manipulation similar to that of spin‐echo imaging, with selection of a pseudo‐echo‐time parameter and a TR interval. With a TR of 2 seconds, eight 256 × 256 images are obtained in 34 seconds with either T2 or proton‐density weighting. A direct comparison between FAISE and spin echo for obtaining T2‐weighted head images in healthy subjects indicates that FAISE and spin‐echo images are qualitatively and quantitatively similar. Image artifacts are more pronounced on “proton‐density” FAISE images than on the T2‐weighted FAISE images. T1 contrast can be obtained with inversion recovery and short TR FAISE images. Preliminary temperature measurements in saline phantoms do not indicate excessive temperature increases with extended FAISE acquisitions. However, extensive studies of radio‐frequency power deposition effects should be performed if the FAISE technique is to be fully exploited.
Electrocardiograph‐independent, “wireless” cardiovascular cine MR imaging
Authors: White Richard D. , Paschal Cynthia B. , Clampitt Mark E. , Spraggins Thomas A. , Lenz Gerald W. 
Published: March 2007

AbstractA new electrocardiograph (ECG)‐independent, “wireless” gating technique for cine magnetic resonance (MR) imaging was evaluated in 23 cases of cardiovascular disease; in each case, standard ECG‐dependent image loops were available for comparison. The ECG‐independent strategy references cine MR imaging data retrospectively to inherent periodic changes in MR signal related to the cardiac cycle. With a “double‐section” method, both timing data reflecting such changes and imaging data can be acquired simultaneously. “Artificial R waves” are extracted from the timing data acquired with a projection approach. The ECG‐independent image loops were diagnostic in 91 % of cases. Their overall image quality was at least equal to that of available ECG‐dependent versions in only 39% of cases, but this proportion increased to 53% if cases with suboptimal imaging orientations for monitoring of the motion‐dependent signal changes were excluded. Orientation appeared to be the primary technical limitation associated with this ECG‐independent technique; however, poor ventricular function also significantly impaired performance. Improvement in the performance of the ECG‐independent strategy is anticipated with technical advances.
Application of a connected‐voxel algorithm to MR angiographic data
Authors: Saloner David , Hanson William A. , Tsuruda Jay S. , van Tyen Rem , Anderson Charles M. , Lee Ralph E. 
Published: March 2007

AbstractA connected‐voxel algorithm (CVA) that improves the contrast and conspicuity of blood vessels in maximum‐intensity‐projection (MIP) magnetic resonance (MR) angiography is described. Images from a variety of anatomic regions in healthy volunteers were calculated with either an MIP procedure alone or with data that had first been processed with the CVA. A low‐signal‐intensity threshold is first applied to separate groups of voxels associated with different vessels from one another and to eliminate the contribution from low‐intensity stationary material. The remaining voxels are grouped by a connectivity criterion into discrete “objects.” Vessels are represented by extended objects, and small objects are discarded. The CVA, therefore, reduces the full three‐dimensional data set into a small number of discrete objects. It is a powerful technique that can be used to remove signal from vessels overlying the vessel of interest, to separate objects representing arterial flow from those representing venous flow, to eliminate flow artifact from projection images, and to more completely retain signal within the vascular lumen. This technique has been successfully demonstrated with MR angiography in healthy volunteers.