bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laterality, region, and type of motor dysfunction correlate with cognitive impairment in Parkinson's disease
Authors: Williams Lindsy N. , Seignourel Paul , Crucian Gregory P. , Okun Michael S. , Rodriguez Ramon L. , Skidmore Frank M. , Foster Paul S. , Jacobson Charles E. , Romrell Janet , Bowers Dawn , Fernandez Hubert H. 
Published: November 2006

AbstractWe studied the relationship between two screening cognitive measures and off motor Unified Parkinson's Disease Rating Scale (UPDRS) scores in 108 Parkinson's disease patients. Multiple regressions were conducted to examine the UPDRS subscores' unique contributions to cognitive function. When including bradykinesia, rigidity, and postural/gait instability subscores, only bradykinesia predicted Mini Mental Status Examination (MMSE), normalized β = −0.57, t(104) = −3.31, P < 0.01, and Dementia Rating Scale‐2 (DRS‐2), normalized β = −0.45, t(104) = −2.55, P < 0.05. Tremor was not included in the regression analyses because it did not correlate with cognitive function. When including axial and appendicular subscores, only the axial subscore predicted MMSE, normalized β = −0.39, t(105) = −3.19, P < 0.01, and DRS‐2 scores, normalized β = −0.40, t(106) = −3.28, P < 0.01. When including left‐sided and right‐sided subscores, only the right‐sided symptoms predicted DRS‐2 scores, normalized β = −0.28, t(105) = −2.45, P < 0.05, and showed a trend toward predicting MMSE scores, normalized β = −0.22, t(105) = −1.95, P = 0.054. We therefore found that right‐sided symptoms (for laterality), axial symptoms (for region), and bradykinesia (for type of symptoms) were thebest predictors of cognitive function. © 2006 Movement Disorder Society
Sodium MRI of the human kidney at 3 Tesla
Authors: Maril Nimrod , Rosen Yael , Reynolds Glenn H. , Ivanishev Alex , Ngo Long , Lenkinski Robert E. 
Published: November 2006

AbstractThe sodium concentration gradient in the kidney (from the cortex to the medulla) serves to regulate fluid homeostasis and is tightly coupled to renal function. It was previously shown that renal function and pathophysiology can be characterized in rat kidneys by measuring the sodium gradient with 23Na MRI. This study demonstrates for the first time the ability of 23Na MRI to map the distribution of sodium in the human kidney and to quantify the corticomedullary sodium gradient. The study was performed on a 3T Signa LX scanner (GE) using an in‐house‐built quadrature surface coil. 23Na images of volunteers were acquired using a 3D coronal gradient‐echo sequence at a spatial resolution of 0.3 × 0.3 × 1.5 cm3 in a 25‐min scan time. The signal intensity (relative to the noise) increased linearly from the cortex to each of the medullae with a mean slope of 1.6 ± 0.2 in relative arbitrary units per mm (Rel.u./mm, N = 6) and then decreased, as expected, toward the renal pelvis. Water deprivation (12 hr) induced a significant increase of 25% (P < 0.05) in this gradient. Based on these results, we suggest that sodium MRI can serve as a valuable noninvasive method for functional imaging of the human kidney. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Fast 3D radiofrequency field mapping using echo‐planar imaging
Authors: Jiru F. , Klose U. 
Published: November 2006

AbstractAn inhomogeneous radiofrequency (RF) magnetic field is an essential source of error for the quantification of MRI and MRS parameters. To correct for effects of RF inhomogeneities in 3D data sets, it is necessary to have knowledge of the 3D RF distribution in the sample. In this paper a method for fast 3D RF mapping is presented. The method is based on the simultaneous acquisition of a spin echo (SE) and a stimulated echo (STE) using echo‐planar imaging (EPI). The acquisition of the 3D RF map using 64 partitions and TR = 500 ms requires 1.5 min. The use of the sequence in vivo is demonstrated by the calculation of the RF maps in the human brain at 3T. The comparison of calculated flip angles with the flip angles obtained by fitting signal behavior in the 3D stimulated‐echo acquisition mode (STEAM)‐EPI sequence and the analysis of errors due to spatially dependent T1 values in the brain show that the accuracy of the calculated flip angles in the human brain is about 2°. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Intrinsic fat suppression in TIDE balanced steady‐state free precession imaging
Authors: Paul Dominik , Hennig Jürgen , Zaitsev Maxim 
Published: November 2006

AbstractA novel fat‐suppressed balanced steady‐state free precession (b‐SSFP) imaging method based on the transition into driven equilibrium (TIDE) sequence with variable flip angles is presented. The new method, called fat‐saturated (FS)‐TIDE, exploits the special behavior of TIDE signals from off‐resonance spins during the flip angle ramp. As shown by simulations and experimental data, the TIDE signal evolution for off‐resonant isochromats during the transition from turbo spin‐echo (TSE)‐like behavior to the true fast imaging with steady precession (TrueFISP) mode undergoes a zero crossing. The resulting signal notch for off‐resonant spins is then used for fat suppression. The efficiency of FS‐TIDE is demonstrated in phantoms and healthy volunteers on a 1.5T system. The resulting images are compared with standard TrueFISP data with and without fat suppression. It is demonstrated that FS‐TIDE provides a fast and stable means for homogenous fat suppression in abdominal imaging while maintaining balanced SSFP‐like image contrast and signal‐to‐noise ratio (SNR). The scan time of FS‐TIDE is not increased compared to normal TrueFISP imaging without fat suppression and identical k‐space trajectories. Because of the intrinsic fat suppression, no additional preparation is needed. Possible repetition times (TRs) are not firmly limited to special values and are nearly arbitrary. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Deconvolution‐interpolation gridding (DING): Accurate reconstruction for arbitrary k‐space trajectories
Authors: Gabr Refaat E. , Aksit Pelin , Bottomley Paul A. , Youssef Abou‐Bakr M. , Kadah Yasser M. 
Published: November 2006

AbstractA simple iterative algorithm, termed deconvolution‐interpolation gridding (DING), is presented to address the problem of reconstructing images from arbitrarily‐sampled k‐space. The new algorithm solves a sparse system of linear equations that is equivalent to a deconvolution of the k‐space with a small window. The deconvolution operation results in increased reconstruction accuracy without grid subsampling, at some cost to computational load. By avoiding grid oversampling, the new solution saves memory, which is critical for 3D trajectories. The DING algorithm does not require the calculation of a sampling density compensation function, which is often problematic. DING's sparse linear system is inverted efficiently using the conjugate gradient (CG) method. The reconstruction of the gridding system matrix is simple and fast, and no regularization is needed. This feature renders DING suitable for situations where the k‐space trajectory is changed often or is not known a priori, such as when patient motion occurs during the scan. DING was compared with conventional gridding and an iterative reconstruction method in computer simulations and in vivo spiral MRI experiments. The results demonstrate a stable performance and reduced root mean square (RMS) error for DING in different k‐space trajectories. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Quantifying the performance effects of idle time utilization in multiserver systems
Authors: Tian Naishuo , Zhang Zhe George 
Published: November 2006

AbstractIn many practical multiserver queueing systems, servers not only serve randomly arriving customers but also work on the secondary jobs with infinite backlog during their idle time. In this paper, we propose a c‐server model with a two‐threshold policy, denoted by (e d), to evaluate the performance of this class of systems. With such a policy, when the number of idle servers has reached d (<c), then e (<d) idle agents will process secondary jobs. These e servers keep working on the secondary jobs until they find waiting customers exist in the system at a secondary job completion instant. Using the matrix analytic method, we obtain the stationary performance measures for evaluating different (e, d) policies. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007.
On valuing appreciating human assets in services
Authors: Zeynep Akşin O. 
Published: November 2006

AbstractThis paper derives optimal policies for when to hire, train, and lay off employees in service organizations when worker productivity appreciates deterministically or stochastically under constant, monotonic, and cyclic service demand. The model, an extension of the machine replacement problem from the engineering economy literature, uses infinite horizon linear programming to produce optimal personnel planning strategies and dual prices that characterize the workforce's economic value. The effect of employee attrition is also considered. In its valuation of human assets, unlike pure accounting approaches that only try to measure, this paper proposes an approach to capture the interaction between firm decisions pertaining to human resources and human resource value. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007
Uniformly optimal digraphs for strongly connected reliability
Authors: Brown J.I. , Li Xiaohu 
Published: November 2006

AbstractBoesch et al. conjectured that for any n and m there exists a uniformly optimal (n,m)–graph Gn,m for all terminal reliability, that is, the all‐terminal reliability of Gn,m is at least as large as the all‐terminal reliability of any other graph G with n vertices and m edges, no matter what the probability of an edge being operational is. Although there are counterexamples known when one restricts attention to simple graphs, the conjecture remains open when one allows parallel edges. We consider the analogous problem for strongly connected reliability, that is, the probability that a digraph contains a spanning strongly connected subdigraph, given that each vertex is operational, but arcs are independently operational with probability p. We show that there do indeed exist uniformly optimal digraphs for strongly connected (n,m)–digraphs. We also show that if one restricts attention to simple digraphs (without parallel arcs) then such uniformly optimal digraphs need not exist. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 49(2), 145–151 2007
On super edge‐connectivity of Cartesian product graphs
Authors: Lü Min , Chen Guo‐Liang , Xu Jun‐Ming 
Published: November 2006

AbstractThe super edge‐connectivity λ′ of a connected graph G is the minimum cardinality of an edge‐cut F in G such that every component of G − F contains at least two vertices. Let Gi be a connected graph with order ni, minimum degree δi and edge‐connectivity λi for i = 1, 2. This article shows that λ′(G1 × G2) ≥ min{n1λ2, n2λ1, λ1 + 2 λ2, 2 λ1 + λ 2} for n1, n2 ≥ 3 and λ′(K2 × G2) = min{ n2, 2λ2}, which generalizes the main result of Shieh on the super edge‐connectedness of the Cartesian product of two regular graphs with maximum edge‐connectivity. In particular, this article determines λ′(G1 × G2) = min{n1δ2, n2δ1, ξ{G1 × G2)} if λ′(Gi) = ξ(Gi), where ξ(G) is the minimum edge‐degree of a graph G. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 49(2), 152–157 2007
Theoretical modeling of chemical reactions in complex environments: the intramolecular proton transfer in aqueous malonaldehyde
Authors: Aschi Massimiliano , D'Abramo Marco , Ramondo Fabio , Daidone Isabella , D'Alessandro Maira , Di Nola Alfredo , Amadei Andrea 
Published: November 2006

AbstractThe free energy profile and the (classical) kinetics of chemical reactions in (soft) condensed phase are modeled theoretically by means of molecular dynamics simulations, the Perturbed Matrix Method (PMM) and the quasi Gaussian entropy (QGE) theory. In this paper we describe the theoretical framework and apply the model to the intramolecular proton transfer reaction of aqueous malonaldehyde. Although in the present application we disregard the quantum effects for the proton dynamics along the reaction coordinate (i.e., tunneling), the classical‐like view of the proton transition over the reaction free energy surface seems to properly describe the kinetic process and shows that water acts lowering the reaction free energy barrier. Moreover, a weak temperature dependence of the free energy surface is obtained, implying small entropy variations in the transition. Interestingly the activation entropy, as provided by the QGE model, is negative in the whole temperature range considered, thus indicating an entropy reduction at the transition structure. Finally, by comparing our results with theoretical and experimental literature data, we critically address the actual role of tunneling in this reaction and discuss the emerging kinetic scheme. Copyright © 2006 John Wiley & Sons, Ltd.
An improved characteristic molecular volume parameter for linear solvation energy relationships of acyclic alkanes
Authors: Palatinus Joseph A. , Carroll Felix A. , Argenton André B. , Quina Frank H. 
Published: November 2006

AbstractBoiling point numbers (YBP) of acyclic alkanes serve as the basis for an improved characteristic molecular volume parameter (VY) for use in linear solvation energy relationships. These VY values correlate much better than do Abraham–McGowan V values with a wide range of physical properties of acyclic alkanes, including vapor pressure, log L16 values, HPLC and GC retention indices, and aqueous solubilities. The VY parameter may be determined easily from literature boiling point data. Alternatively, it may be calculated from boiling points predicted by a wide variety of group contribution, connectivity, or computational methods when the experimental boiling point is unavailable. Thus, the results reported here enable fundamental physical properties of acyclic alkanes to be predicted directly from molecular structure. Copyright © 2006 John Wiley & Sons, Ltd.
Amide and lactam hydrolysis of N‐(2‐hydroxyacetyl)‐2‐pyrrolidone: effective catalysis
Authors: Borboa Lisaedy García , Núñez Oswaldo 
Published: November 2006

AbstractWhen N‐(2‐hydroxyacetyl)‐2‐pyrrolidone (open form) is dissolved in water at pH > 8, irreversible cleavage of the exocyclic and endocyclic amide CN bond occurs. The latter rupture corresponds to the lactam opening yielding N‐(4‐hydroxyacetyl)butanoic acid (NBA). NBA is produced from the ester hydrolysis of the ester‐amide macrocycle that is in equilibrium with the cyclol form of the open form. We have previously reported this latter equilibrium for N‐(2‐aminoacetyl)‐2‐lactams. 2‐pyrrolidone (lactam) and glycolic acid are produced from direct hydrolysis of the open form by means of the amide exocyclic cleavage. The [NBA]/[lactam] ratio increases at higher pH since the NBA production is second order with respect to [OH−] while the corresponding lactam formation is only first order. The obtained kobs is hence the sum of the rate constants that yield lactam and NBA, respectively. This kobs is uncatalyzed and specific base catalyzed with unusually high rate constants of 2.1 × 10−6 s−1 and 0.025 M−1 s−1, respectively. The stability of the corresponding tetrahedral intermediate formed and the intramolecular alkoxy nucleophilic attack on the lactam carbonyl group combined with an effective protonation of the lactam nitrogen that promotes the CN cleavage, contribute to increase the reaction rates and lactam opening. Rate constants for the two parallel reactions are obtained from kobs and [NBA]/[lactam] versus pH plots. Copyright © 2006 John Wiley & Sons, Ltd.
Electron transfer reactions (ETR) of tert‐butyl perbenzoates with dimethyl sulfide: the rates controlled by translational entropy
Authors: Kim Sung Soo , Lim Sang Hak 
Published: November 2006

AbstractVarious tert‐butyl perbenzoates were prepared according to the known methods. The mixtures of tert‐butyl perbenzoate and dimethyl sulfide underwent thermolysis at several temperatures (T °C: 80, 90, 100, and 110). The rates of consumption of the peresters (kobs) were obtained from ln C0/Ct = kobs × t where C0 and Ct are the concentration of the perester at time 0 and t, respectively. For example: The decrease of the perester satisfied pseudo first order kinetics, and kobswere determined. kHom. and kET were obtained from kobs = kHom. + kET[CH3SCH3] where [CH3SCH3]/[perester] > 10. kET and its relative rates are produced from plot of kobs against [CH3SCH3]. Hammett correlation are plotted against σ and σ+ in which σ is better correlated than σ+. Hammett ρ could be considered selectivity which stays constant irrespective of temperature. The phenomenon is not consistent with reactivity/selectivity principle. The differential activation entropies linearly increase with substituent constant σ to give slope of 2.63 while the similar slope for differential enthalpies shows much lower value of 0.892. The dominance of differential entropic terms clearly indicates the entropy control of the rates. Copyright © 2006 John Wiley & Sons, Ltd.
Engineering functional materials by halogen bonding
Authors: Metrangolo Pierangelo , Resnati Giuseppe , Pilati Tullio , Liantonio Rosalba , Meyer Franck 
Published: November 2006

AbstractEngineering functional materials endowed with unprecedented properties require the exploitation of new intermolecular interactions, which can determine the characteristics of the bulk materials. The great potential of Halogen Bonding (XB), namely any noncovalent interaction involving halogens as electron acceptors, in the design of new and high‐value functional materials is now emerging clearly. This Highlight will give a detailed overview on the energetic and geometric features of XB, showing how some of them are quite constant in most of the formed supramolecular complexes (e.g., the angle formed by the covalent and the noncovalent bonds around the halogen atom), while some others depend strictly on the nature of the interacting partners. Then, several specific examples of halogen‐bonded supramolecular architectures, whose structural aspects as well as applications in fields as diverse as enantiomers' separation, crystal engineering, liquid crystals, natural, and synthetic receptors, will be fully described. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: PolymChem 45: 1–15, 2007
An analysis of the psychometric profile and frequency of anxiety and depression in Australian men with prostate cancer
Authors: Sharpley Christopher F. , Christie David R. H. 
Published: November 2006

AbstractZung's Self‐Rating Anxiety Scale and Self‐Rating Depression Scale were used to collect data from 195 Australian men who had received a diagnosis of prostate cancer. Analysis was via separate scales and also by combining both scales into a single unit to assess anxiety–depression and then analysing the underlying component structure of that unit. Applying Zung's recommended cutoff scores, 12% of the sample were classified as having clinically significant levels of anxiety and 16% had similar levels of depression. Factor analysis of the combined SAS and SDS indicated four major components which reflected a process of: loss of functional capacity, worthlessness and hopelessness, fear and somatic symptomatology. Implications for the effective assessment and treatment of anxiety and depression in prostate patients are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Associated and predictive factors of sleep disturbance in advanced cancer patients
Authors: Akechi Tatsuo , Okuyama Toru , Akizuki Nobuya , Shimizu Ken , Inagaki Masatoshi , Fujimori Maiko , Shima Yasuo , Furukawa Toshiaki A. , Uchitomi Yosuke 
Published: November 2006

AbstractLittle attention has been paid to sleep disturbance experienced by advanced cancer patients. The purpose of the present study was to investigate longitudinal change in sleep disturbance and to identify factors that associated with and predicted sleep disturbance among 209 consecutive terminally ill cancer patients. Patients were assessed twice for sleep disturbance by one item of the structured clinical interview for assessing depression, once at the time of their registration with a palliative care unit (PCU) (baseline) and again at the time of their PCU admission (follow‐up), and possible associated medical and psychosocial factors were evaluated. The proportions of patients with obvious sleep disturbance at baseline and follow‐up were 15.3 and 25.9%, respectively. Sixty‐seven percent of the subjects showed some sleep status changes, including both aggravation and improvement, between baseline and follow‐up. Being younger, having diarrhea and living alone were significantly associated with sleep disturbance at baseline, and the increase of psychological distress was the only significant predictive factor for sleep disturbance at follow‐up. These findings suggest that psychological distress is a possible key cause of sleep disturbance and management of psychological distress may be one promising strategy for prevention of sleep disturbance among advanced cancer patients. Copyright © 2006 John Wiley & Sons, Ltd.
From quantum dots to terahertz radiation
Authors: Vaughan M. P. 
Published: November 2006

AbstractConference Reports are meant to offer an authoritative view on a recently held scientific meeting rather than a comprehensive list of the conference presentations. Authors are invited to describe what they feel were the most interesting contributions. The ICSNN 2006 Conference was devoted to new phenomena in the physics and technology of superlattices, nanostructures and nanoscale devices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Predicting pulmonary hypoplasia using the sonographic fetal lung volume to body weight ratio — how precise and accurate is it?
Authors: Ruano R. , Martinovic J. , Aubry M. ‐C. , Dumez Y. , Benachi A. 
Published: November 2006

AbstractObjectivesTo determine the precision and accuracy of ultrasound in estimating the fetal lung to body weight ratio (FLB ratio) using two‐dimensional (2D) and three‐dimensional (3D) ultrasound by comparison with postmortem measurements, and to evaluate its potential to diagnose pulmonary hypoplasia.MethodsLung volumes were estimated by 3D ultrasound (rotational technique) and fetal weights were measured by 2D ultrasound (Hadlock equation) in 35 fetuses immediately before termination of pregnancy at 15–38 weeks. Sonographic estimates of FLB ratio were compared with postmortem values. Based on the pathological definition of pulmonary hypoplasia, the accuracy of sonographic estimation of the FLB ratio was analyzed.ResultsThe mean gestational age at termination of pregnancy was 26.7 (range, 15–38) weeks. The mean FLB ratios were 0.018 (SD, 0.006) on ultrasound and 0.019 (SD, 0.007) at autopsy (P = 0.730). Bias and precision of sonographic FLB ratio were − 0.001 and 0.003 (absolute limits, − 0.007 to + 0.006), respectively. Pulmonary hypoplasia was diagnosed in 12 (34.3%) cases at autopsy. The sonographic FLB ratio was significantly lower in fetuses with pulmonary hypoplasia at autopsy (median, 0.011; range, 0.004–0.014) than it was in those without pulmonary hypoplasia (median, 0.022; range, 0.013–0.045, P < 0.001). The sensitivity and specificity of the sonographic FLB ratio for diagnosing pulmonary hypoplasia were 91.7% (11/12) and 91.3% (21/23), respectively, the positive and negative predictive values were 84.6% (11/13) and 95.5% (21/22), and the accuracy was 91.4% (32/35).ConclusionFLB ratio can be estimated precisely on ultrasound examination, albeit with wide limits of agreement. The sonographically estimated FLB ratio may be useful in the prediction and diagnosis of pulmonary hypoplasia. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.