bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substituent Effects on the Low‐Frequency Vibrational Modes of Benzoic Acid and Related Compounds
Authors: Ge Min , Zhao Hong‐Wei , Wang Wen‐Feng , Yu Xiao‐Han , Li Wen‐Xin 
Published: March 2007

AbstractWell‐resolved absorption spectra of benzoic acid and its derivatives with one hydrogen atom replaced by a substituent group CH3, OH, NH2 or NO2 were reported in the frequency region between 6 and 67 cm−1 at room temperature with terahertz time‐domain spectroscopy (THz‐TDS). These substances can be distinguished easily based on the terahertz absorption spectra. The measurements suggested that even minor changes in the molecular configuration and chemical composition lead to distinct differences in THz spectrum. Density functional theory (DFT) method was used to assist the analysis and assignment of the individual THz absorption spectra of benzoic acid and its methyl derivatives. Observed THz responses of samples can be assigned to the collective vibrations associated with intermolecular hydrogen bonds.
Investigation on Concentrated V(IV)/V(V) Redox Reaction by Rotating Disc Voltammetry
Authors: Wen Yue‐Hua , Zhang Hua‐Min , Qian Peng , Ma Hai‐Peng , Yi Bao‐Lian , Yang Yu‐Sheng 
Published: March 2007

AbstractThe kinetic characteristics of the concentrated V(IV)/V(V) couple have been studied at a glassy carbon electrode in sulfuric acid using rotating‐disc electrode and cyclic voltammetry. The kinetics of the V(IV)/V(V) redox couple reaction was found to be electrochemically quasi‐reversible with the slower kinetics for the V(V) reduction than that for the V(IV) oxidation. And, dependence of diffusion coefficients and kinetic parameters of V(IV) species on the V(IV) and H2SO4 concentration was investigated. It is shown that the concentration of active species V(IV) should be over 1 mol·L−1 for the redox flow battery application. Further, with increasing the V(IV) and H2SO4 concentration, the diffusion coefficients of V(IV) were gradually reduced whereas its kinetics was improved considerably, especially in the case of V(IV) and H2SO4 up to 2 and 4 mol·L−1.
Synthesis of Furano[3,2‐c]‐ and Pyrano[3,2‐c]quinolines upon Imino Diels‐Alder Reactions Initiated by Nitrosonium (NO+)
Authors: Zhou Yu‐Lu , Jia Xiao‐Dong , Li Rui , Han Bing , Wu Long‐Min 
Published: March 2007

AbstractEfficient nitrosonium (NO+)‐initiated aza‐Diels‐Alder reactions of N‐arylimines with 2,3‐dihydrofuran or 3,4‐dihydro‐2H‐pyran allowed access to furano[3,2‐c]‐ or pyrano[3,2‐c]quinolines. A mixture of cis and trans‐quinoline isomers was obtained in various ratios and yields.
The Ancient and Honourable Art of Shimming
Authors: Chmurny Gwendolyn N. , Hoult David I. 
Published: March 2007

AbstractThe fundamental physics underlying the art of shimming a high‐resolution NMR superconducting magnet is described, and the rationale of the design of shim coils, together with their various appelations, is discussed. The effects of the various shims on a free induction decay and the ensuing spectrum are illustrated, and the use of a spinning sample is advocated for rapidly diagnosing and eliminating field inhomogeneity. The problems caused by impure shims and interactions among orders are highlighted, and the reasons for the interactions are given, together with strategies to help combat their time‐consuming and destructive effects.
Elevated expression of vascular endothelial growth factor correlates with increased angiogenesis and decreased progression‐free survival among patients with low‐grade neuroendocrine tumors
Authors: Zhang Jun , Jia Zhiliang , Li Qiang , Wang Liwei , Rashid Asif , Zhu Zhenggang , Evans Douglas B. , Vauthey Jean‐Nicolas , Xie Keping , Yao James C. 
Published: March 2007

AbstractBACKGROUNDVascular endothelial growth factor (VEGF) is a critical proangiogenic factor in solid tumors. However, its expression and role in human neuroendocrine tumor development and progression remains unclear.METHODSUsing immunohistochemistry, VEGF and Sp1 expression patterns were investigated in 50 cases of human gastrointestinal neuroendocrine tumor having various clinicopathologic characteristics.RESULTSIt was found that strong VEGF expression was detected in tumor cells, whereas no or very weak VEGF expression was detected in stromal cells surrounding or within the tumors. The levels of VEGF expression directly correlated with the expression levels of Sp1 and microvessel density. Strong, weak, and negative VEGF expression was observed in 32%, 54%, and 14% of cases, respectively. Compared with the group with negative VEGF expression, VEGF (weak/strong) expression was associated with metastasis (14% versus 58%; P = .03). The median progression‐free survival (PFS) durations of patients with strong and weak VEGF expression were 29 months and 81 months, respectively. With a median follow‐up duration of 50 months, the median PFS duration for the group with negative VEGF expression has not been reached. Compared with the log‐rank test, VEGF expression was associated with poor PFS (P = .02). Using in vitro and in vivo models, human carcinoid cell lines were treated with bevacizumab, a monoclonal antibody targeting VEGF. Bevacizumab did not inhibit the growth of carcinoid cells in vitro but significantly reduced tumor angiogenesis and impaired tumor growth in animals.CONCLUSIONSThe data suggest that overexpression of VEGF promotes the growth of human neuroendocrine tumors in part through up‐regulation of angiogenesis. Cancer 2007. © 2007 American Cancer Society.
Late toxicity and biochemical recurrence after external‐beam radiotherapy combined with permanent‐source prostate brachytherapy
Authors: Lee W. Robert , Bae Kyoungwha , Lawton Colleen , Gillin Michael , Morton Gerard , Firat Selim , Baikadi Madhava , Kuettel Michael , Greven Kathryn , Sandler Howard 
Published: March 2007

AbstractBACKGROUNDThe combination of external‐beam radiotherapy and brachytherapy is used commonly to treat men with prostate cancer. In this analysis, the authors examined the rate of biochemical recurrence (BR) and late grade ≥3 genitourinary (GU) and gastrointestinal (GI) toxicity after treatment with external‐beam radiotherapy and brachytherapy in a multiinstitutional, cooperative group setting.METHODSAll eligible patients received external‐beam radiotherapy (45 Gray [Gy] in 25 fractions) followed 2 to 6 weeks later by an interstitial implant using iodine‐125 to deliver an additional 108 Gy. BR was defined in 2 ways: according to the American Society for Therapeutic Radiology and Oncology (ASTRO) Consensus Definition (ACD) and according to the Phoenix definition (PD) (prostate‐specific antigen nadir +2 ng/mL). The Radiation Therapy Oncology Group(RTOG)/European Organization for Research and Treatment of Cancer late radiation morbidity scoring system was used to grade all toxicity.RESULTSOne hundred thirty‐eight patients were enrolled, and 130 were eligible for the current analysis. The median follow‐up for surviving patients was 49 months (range, 20–60 months). The 48‐month estimate of late grade ≥3 GU/GI toxicity was 15% (95% confidence interval [95% CI], 8–21%), and the 48‐month estimate of BR was 19% (95% CI, 12–26%) and 14% (95% CI, 8–20%) according to the ACD and PD, respectively.CONCLUSIONSThe morbidity observed in this multiinstitutional, cooperative group study was slightly higher than that reported in recent RTOG studies using brachytherapy alone or high‐dose external‐beam radiotherapy. The BR rate observed in this report was similar to that observed with high‐dose external‐beam radiotherapy alone in similar patients. Cancer 2007. © 2007 American Cancer Society.
Influence of body mass index on prostate‐specific antigen failure after androgen suppression and radiation therapy for localized prostate cancer
Authors: Efstathiou Jason A. , Chen Ming‐Hui , Renshaw Andrew A. , Loffredo Marian J. , D'Amico Anthony V. 
Published: March 2007

AbstractBACKGROUNDIncreasing body mass index (BMI) is associated with shorter time to prostate‐specific antigen (PSA) failure after radical prostatectomy. Whether BMI is associated with time to PSA failure was investigated in men treated with androgen suppression therapy (AST) and radiation therapy (RT) for clinically localized prostate cancer.METHODSThe observational prospective cohort study consisted of 102 men with clinically localized prostate cancer who received 70 Gy RT with 6 months of AST on a single arm of a randomized trial between December 1995 and April 2001. Height and weight data were available at baseline for 99 (97%) of the men, from which BMI was calculated. Adjusting for age (continuous) and known prognostic factors including PSA level (continuous), Gleason score, and T‐category, Cox regression analyses were performed to analyze whether BMI (continuous) was associated with time to PSA failure (PSA >1.0 ng/mL and increasing >0.2 ng/mL on 2 consecutive visits).RESULTSMedian age and median BMI (interquartile range [IQR]) at baseline was 72 (69.1–74.7) years and 27.4 (24.8–30.7) kg/m,2respectively. In addition to an increasing PSA level (P= .006) and Gleason 8–10 cancer (P= .024), after a median follow‐up (IQR) of 6.9 (5.6–8.5) years, an increasing BMI was also significantly associated with a shorter time to PSA failure (adjusted hazard ratio [HR]: 1.10; 95% confidence interval [CI]: 1.01–1.19;P= .026) after RT and AST.CONCLUSIONSAfter adjusting for known prognostic factors, baseline BMI is significantly associated with time to PSA failure after RT and AST for men with clinically localized prostate cancer. Further study is warranted to assess the impact of an increasing BMI after AST administration on PSA failure, prostate cancer‐specific, and all‐cause mortality. Cancer 2007. © 2007 American Cancer Society.
Anion and Cation Effects on Imidazolium Salt Melting Points: A Descriptor Modelling Study
Authors: López‐Martin Ignacio , Burello Enrico , Davey Paul N. , Seddon Kenneth R. , Rothenberg Gadi 
Published: March 2007

AbstractThe challenge of predicting the melting point of ionic liquids is outlined. A descriptor modelling approach for two separate sets of ionic liquids is presented. In each case, the cations and the anions are modelled separately, using quantitative structure–property relationships. Both models include constitutional, topological and geometric descriptors as well as quantum mechanical ones. This approach gives access to (n×m) ionic liquids using only (n+m) calculations. The protocol is tested and validated for predicting the melting points of two sets, comprised of 22 and 62 imidazolium‐based ionic liquids, respectively. Good correlations and predictions are obtained in both cases. Within the data set selected (only monopositive and mononegative ions are studied, and so total charge was not a factor), the degree of sphericity is the most important variable for the anion, while for the cation the main descriptors pertained to three radial distribution functions that describe three different sections in the cation. These characterise the ionic interactions, the symmetry‐breaking region, and the length of the side chains.
Atypical antipsychotics and polydipsia: a cause or a treatment?
Authors: Bersani Giuseppe , Pesaresi Lorenzo , Orlandi Valerio , Gherardelli Simona , Pancheri Paolo 
Published: March 2007

AbstractPrimary polydipsia (PP) is a frequent complication that affects many chronic schizophrenic inpatients. Due to possible lethal consequences, for example, hyponatremia, coma and death, it's fundamental for the physician achieving early diagnosis and treating this condition. The first step is identifying polydipsia by clinical, biochemical and pharmacological means. Nowadays, the pathophysiology of PP remains unclear, and this limits the possibility of detecting an appropriate drug treatment. Typical antipsychotics have been associated to a worsening of polydipsic behavior, while more recently atypical antipsychotics have been reported as being useful. However results are still mixed and controversial. It appears that risperidone and olanzapine are not clearly effective; clozapine may improve symptoms, although it is difficult to manage from a therapeutic point of view; quetiapine has been poorly studied so far, nonetheless it has given interesting results. Through a case study analysis, this report presents a brief, yet selective, overview of the current state of psychopharmacology in the treatment of PP with atypical antipsychotics in schizophrenia. Copyright © 2007 John Wiley & Sons, Ltd.
Research on seismic modeling and inversion at the center for wave phenomena: Status, february, 1989
Authors: Bleistein Norman , Cohen Jack K. 
Published: March 2007

AbstractThis paper describes the approach and evolution of seismic modeling and inversion research led by the authors for the past 15 years. We trace the development of our work from inversions based on the simplest geometries and background velocity profiles to much more realistic geometries and backgrounds. We also discuss the application of the same ideas to the problem of transformation of data to zero offset (dip moveout). We do this primarily via graphical displays demonstrating various aspects of our theory. A brief description of the theory, in the context of inversion of scalar data in a constant density medium, is also presented.
Bayesian reconstruction for SPECT: Validation with monte carlo simulation, experimental phantom, and real patient data
Authors: Liang Z. , Jaszczak R. , Floyd C. , Greer K. , Coleman R. 
Published: March 2007

AbstractA method for Bayesian image reconstruction from projections is applied to Monte Carlo simulation, experimental phantom, and real patient data from aSPECTacquisition system. This statistical image reconstruction method has three distinct aspects: (1) it usesa prioriinformation about image density distribution of a multinomial process; (2) it considers a spatial correlation of nearby image elements; and (3) it incorporates the Poisson nature of photon detection fluctuation. The Monte Carlo simulation data are generated by computer codes for selected mathematical phantoms containing hot and cold rods. The experimental phantom data are acquired with a TriadSPECTsystem using radioactive phantoms containing hot and cold rods. The real patient data are obtained from a patient brain scan using the TriadSPECTsystem. A parallel beam geometry is used. The data are acquired from 120 projection angles uniformly distributed from 0 to 360 degrees. At each projection angle, a 128 X 128 projection image is measured. This 128 X 128 projection samples are equally spaced along the axis of detector rotation and perpendicular to the axis, respectively. Each image slice is reconstructed using a 128 X 128 pixel array. Comparisons between this Bayesian method and maximum likelihood method and filtered backprojection method are give. An improvement in noise suppression is demonstrated using the Bayesian method while image resolution is preserved.
Evaluators of image reconstruction algorithms
Authors: Herman Gabor T. , Yeung K. T. Daniel 
Published: March 2007

AbstractAn image reconstruction algorithm is supposed to present an image that contains medically relevant information that exists in a cross section of the human body. There is an enormous variety of such algorithms. The question arises: Given a specific medical problem, what is the relative merit of two image reconstruction algorithms in presenting images that are helpful for solving the problem? An approach to answering this question with a high degree of confidence is that of ROC analysis of human observer performance. The problem with ROC studies using human observers is their complexity (and, hence, cost). To overcome this problem, it has been suggested to replace the human observer by a numerical observer. An even simpler approach is by the use of distance metrics, such as the root mean squared distance, between the reconstructed images and the known originals. For any of these approaches, the evaluation should be done using a sample set that is large enough to provide us with a statistically significant result.We concentrate in this paper on the numerical observer approach, and we reintroduce in this framework the notion of the Hotelling Trace Criterion, which has recently been proposed as an appropriate evaluator of imaging systems. We propose a definite strategy (based on linear abnormality‐index functions that are optimal for the chosen figure of merit) for evaluating image reconstruction algorithms. We give details of two experimental studies that embody the espoused principles. Since ROC analysis of human observer performance is the ultimate yardstick for system assessment, one justifies a numerical observer approach by showing that it yields “similar” results to a human observer study. Also, since simple distance metrics are computationally less cumbersome than are numerical observer studies, one would like to replace the latter by the former, whenever it is likely to give “similar” results. We discuss approaches to assigning a numerical value to the “similarity” of the results produced by two different evaluators. We introduce a new concept, called rank‐ordering nearness, which seems to provide us with a promising approach to experimentally determining the similarity of two evaluators of image reconstruction algorithms.
Superhigh image resolution for microwave imaging
Authors: Li Hsueh‐Jyh , Liu Ta‐Yung , Yang Sheng‐Hui 
Published: March 2007

AbstractAlgorithms for extrapolating the scattered field along the frequency direction and the azimuthal direction are developed and analyzed. Their effects on the image resolution for polar format processing and rectangular format processing are discussed. Simulation and experimental results show that extrapolation along the frequency direction does increase the range resolution. While extrapolation along the azimuthal direction improves the cross‐range resolution for small angle imaging, it does not improve image resolution of complex‐shaped objects for wide angle imaging. Both range and cross‐range resolutions can be improved simultaneously for small angle imaging using rectangular format processing if the angular interval and the resolution cells are suitably chosen. A promising application for the algorithms developed is in microwave dynamic imaging.
Resolution analysis of tomographic reconstruction of electron density profiles in the Ionosphere
Authors: Na Helen , Lee Hua 
Published: March 2007

AbstractTraditionally, knowledge of the ionospheric electron density is obtained using Faraday rotation or differential Doppler techniques which measure total electron content in columns of the ionosphere. Conventional data processing can only image the electron density in the direction perpendicular to these columns, thereby forming one‐dimensional images. Because this data is proportional to line integrals through the region of interest, tomographic techniques may be used to reconstruct two‐dimensional electron density images. In this paper, the resolution limit of the image reconstruction process is analyzed in terms of limited‐angle tomography.
Unsupervised estimation of speckle noise in radar images
Authors: Lee Jong‐Sen , Hoppel Karl , Mango Stephen A. 
Published: March 2007

AbstractSpeckle in radar images has the characteristic of a multiplicative noise. In this article, two unsupervised methods are introduced to estimate the speckle noise statistics using the mean and the standard deviation of small image blocks (4 × 4, or 6 × 6 pixels). Since most radar images contain many small homogeneous areas, a scatter plot of the standard deviation versus the mean can reveal the characteristic of the noise. The blocks from inhomogeneous areas have higher values for the standard deviation, and they are scattered above the main cluster. They are considered as outliers, and should be excluded in the statistical estimation. These two methods are designed for obtaining a linear fit in the scatter plot by ignoring outliers. Several synthetic aperture radar(SAR) images are used for illustration.
Investigations of the ionosphere by satellite radiotomography
Authors: Kunitsyn V. E. , Andreeva E. S. , Tereshchenko E. D. , Khudukon B. Z. , Nygrén T. 
Published: March 2007

AbstractAn overview of tomographic approach to remote sensing of ionosphere by radio waves is presented. Various methods, including diffraction, statistical, and ray radiotomography are discussed. The experimental procedures of satellite radiotomography are described. Results from satellite experiments in 1984–1993 are shown demonstrating the great possibilities of the radiotomographic method in ionospheric research.©1994 John Wiley & Sons Inc
Russian‐American tomography experiment
Authors: Foster J. C. , Buonsanto M. J. , Holt J. M. , Klobuchar J. A. , Fougere P. , Pakula W. , Raymund T. D. , Kunitsyn V. E. , Andreeva E. S. , Tereshchenko E. D. , Khudukon B. Z. 
Published: March 2007

AbstractTo intercompare various techniques used in reconstructing tomographic images, and to benchmark those results with direct observations obtained by the incoherent scatter technique, an experimental campaign and subsequent analysis program‐the Russian‐American Tomography experiment (RATE)‐were implemented in late 1993. Russian experiment teams from the Polar Geophysical Institute in Murmansk and Moscow State University joined with American investigators from the Phillips Laboratory and the Massachusetts Institute of Technology, and an array of four receiving stations was set up in the northeastern United States and in eastern Canada to obtain data for the tomographic reconstructions. Phase‐difference and total‐phase tomographic reconstruction techniques have been employed and are intercompared. The spatial/altitude distribution of ionospheric electron content was observed by the MIT Millstone Hill incoherent scatter radar that scanned the ionosphere in a plane parallel to the satellite overflights. We present preliminary reconstructions of the ionospheric structure observed during a severe midlatitude ionospheric storm that took place during the campaign. The drastic large‐scale changes in the ionospheric structure that accompanied the November 1993 storm were well observed by the two diagnostic techniques.©1994 John Wiley & Sons Inc
Imaging the ionosphere with the global positioning system
Authors: Hajj G. A. , Ibañez‐Meier R. , Kursinski E. R. , Romans L. J. 
Published: March 2007

AbstractObserving the Global Positioning System with a satellite in low earth orbit in an occulting geometry provides a powerful means of imaging the ionosphere. Tomographic imaging of the ionosphere from space and ground is examined using singular value decomposition analysis. The resolution and covariance matrices are examined, and simulations are performed that indicate that space data are significantly more effective than ground data in resolving both horizontal and vertical structures, such as the E layer, can be probed with occultation data.©1994 John Wiley & Sons Inc
Nonlinear global and local document degradation models
Authors: Kanungo Tapas , Haralick Robert M. , Phillips Ihsin 
Published: March 2007

AbstractTwo sources of document degradation are modeled: (1) perspective distortion that occurs while photocopying or scanning thick, bound documents; and (2) degradation due to perturbation in the optical scanning and digitization process: speckle, blurr, jitter, and threshold. Perspective distortion is modeled by studying the underlying perspective geometry of the optical system of photocopiers and scanners. An illumination model is described to account for the nonlinear intensity change occurring across a page in a perspective‐distorted document. The optical distortion process is modeled morphologically. First, a distance transform on the foreground is performed; this is followed by a random inversion of binary pixels in which the probability of flip is a function of the distance of the pixel to the boundary of the foreground. Correlating the flipped pixels is modeled by a morphological closing operation.©1994 John Wiley & Sons Inc