bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pressure Dependence in the Methyl Vinyl Ketone+OH and Methacrolein+OH Oxidation Reactions: An Electronic Structure Study
Authors: Ochando‐Pardo Montserrat , Nebot‐Gil Ignacio , González‐Lafont Àngels , Lluch José M. 
Published: July 2005

AbstractHigh‐level electronic structure calculations were carried out for the study of the reaction pathways in the OH‐initiated oxidations of methyl vinyl ketone (MVK) and methacrolein (MACR). For the two conformers of MVK (called synperiplanar and antiperiplanar), the addition channels of OH to the terminal and central carbon atom of the double bond dominate the overall rate constant, whereas the abstraction of the methyl hydrogen atoms has no significant kinetic role. In the case of MACR, only the antiperiplanar conformer is important in its reactivity. In addition, the lower Gibbs free energy barrier for MACR corresponds to the aldehydic hydrogen abstraction reaction, which will be somewhat more favorable than the addition processes. The subtle balance between the different pathways (additions versus abstractions) serves to give an understanding of the pressure dependence of the rate constants of these tropospheric oxidation processes.
Computer and network security risk management: theory, challenges, and countermeasures
Authors: Hamdi Mohamed , Boudriga Noureddine 
Published: July 2005

AbstractThe need to secure information systems and networked infrastructures is now commonplace in most enterprises. The use of novel communication technologies has became a crucial factor that can considerably improve or affect productivity. This is essentially due to the importance of the information transmitted across communication networks and stored in servers. As a consequence, strong ties are being built between security and the enterprise business activity. Risk management, which is the discipline that deals with this aspect, integrates a litany of architectures, techniques, and models that are described in this paper. A global view is proposed to the reader through a presentation of the research activity that has been directed towards this field. Copyright © 2005 John Wiley & Sons, Ltd.
Energy well spent fighting the diabetes epidemic
Authors: Stannard S. R. , Johnson N. A. 
Published: July 2005

AbstractAs the global burden of type 2 diabetes increases, medical science races to comprehensively understand its molecular aetiology. We suggest that the apparent struggle to seek a pharmacological or molecular victory to the diabetes epidemic is a flawed strategy given that evolution has already provided us with the best medicine. Recent molecular evidence highlights the interaction between muscle fatty acid kinetics in dictating whole body insulin action. Insights from an evolutionary perspective suggest that the ability of the body to evoke insulin resistance and store energy as fat within muscle cells is a normal physiological response to aid our survival during food or carbohydrate scarcity, but this ‘hunter–gatherer physiology’ predisposes to diabetes in a modern environment characterized by ample food availability and muscle inactivity. We contend that the true value of physical activity in the prevention and treatment of insulin resistance has been missed by the medical community because scientific investigation has been constructed upon physical activity recommendations that were never intended for this purpose. These recommendations provide a level of metabolic stress insufficient to be compatible with the expectations of our genes. Copyright © 2005 John Wiley & Sons, Ltd.
Cloning of full‐length zebrafish dcc and expression analysis during embryonic and early larval development
Authors: Fricke Cornelia , Chien Chi‐Bin 
Published: July 2005

AbstractMembers of the DCC family play key roles in axon guidance in vertebrates as well as invertebrates. In zebrafish, only a short partial sequence of the dcc gene has been reported to date. Here, we report the cloning of full‐length zebrafish dcc. Zebrafish DCC shares the typical structure of the DCC subgroup of the immunoglobulin superfamily, consisting of four immunoglobulin and six fibronectin‐type III repeats in the extracellular domain, a single transmembrane domain, and an intracellular domain with three conserved motifs. As a first step toward studying the function of dcc, we analyzed its sequence and characterized its expression pattern during embryonic and larval development. dcc is expressed highly in brain and spinal cord, but distinct staining was also observed in developing pectoral fins, pancreas, intestine, and heart. Thus, dcc may play roles not only in axon guidance, but in morphogenesis and functioning of these organs as well. Developmental Dynamics 234:732–739, 2005. © 2005 Wiley‐Liss, Inc.
Bayesian image decomposition applied to relaxographic imaging
Authors: Brown Truman R. , Ochs Michael F. , Rooney William D. , Stoyanova Radka S. , Li Xin , Springer, Charles S. 
Published: July 2005

AbstractT1 relaxographic imaging is a precise and accurate way to characterize tissue. A number of fast MRI acquisition techniques allow both spatial and magnetization recoveries to be well sampled in reasonable imaging times. However, two limitations common to the analysis of relaxographic imaging data are (1) the assumption of single exponential behavior for each image voxel and (2) the treatment of each pixel as an independent entity. The first assumption disregards tissue heterogeneity known to be present and reduces the information content that can be extracted. The latter assumption reduces both the modeling stability and the accuracy of extracted parameters. A new method that overcomes these limitations is presented here. The method, Bayesian Image Decomposition, recovers individual tissue type magnetization recovery curves and their corresponding tissue‐specific relaxographic images (i.e. segmented images) from a series of inversion recovery images. The general form of the decomposition is given together with its specific implementation to longitudinal relaxographic imaging. The method is validated by comparison of the results with those of the standard method and by comparison across data sets. A specific advantage of the new method is the ability to determine fractional contributions of tissue subtypes to each image voxel. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15;2–9, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20033
Unsupervised learning of nonlinear dependencies in natural images
Authors: Park Hyun‐Jin , Lee Te‐Won 
Published: July 2005

AbstractCapturing dependencies in images in an unsupervised manner is important for many image‐processing applications and for understanding the structure of natural image signals. Data generative linear models such as principal component analysis and independent component analysis (ICA) have shown to capture low‐level features such as oriented edges in images. However, those models only capture linear dependency structures because of its linear model constraints and therefore its modeling capability is limited. We propose a new method for capturing nonlinear dependencies in images of natural scenes. This method is an extension of the linear ICA method and builds on a hierarchical representation. The model makes use of lower‐level linear ICA representation and a subsequent mixture of Laplacian distribution for learning the nonlinear dependencies in an image. The model parameters are learned via the expectation maximization algorithm, and it can accurately capture variance correlation and other high‐order structures in a simple and consistent manner. We visualize the learned variance correlation structure and demonstrate applications to automatic image segmentation and image denoising. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 34–47, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20036
Inlier‐based ICA with an application to superimposed images
Authors: Meinecke Frank C. , Harmeling Stefan , Müller Klaus‐Robert 
Published: July 2005

AbstractThis paper proposes a new independent component analysis (ICA) method which is able to unmix overcomplete mixtures of sparce or structured signals like speech, music or images. Furthermore, the method is designed to be robust against outliers, which is a favorable feature for ICA algorithms since most of them are extremely sensitive to outliers. Our approach is based on a simple outlier index. However, instead of robustifying an existing algorithm by some outlier rejection technique we show how this index can be used directly to solve the ICA problem for super‐Gaussian sources. The resulting inlier‐based ICA (IBICA) is outlier‐robust by construction and can be used for standard ICA as well as for overcomplete ICA (i.e. more source signals than observed signals). © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 48–55, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20037
Lebesgue anisotropic image denoising
Authors: Wei Jie 
Published: July 2005

AbstractThe importance of image denoising can never be overemphasized due to the crucial role it plays in image processing and understanding. As the procedure to weed out noises from real visual signals, it stands as the actual foundation for other analysis schemes. A great many techniques have been developed by researchers from a wide array of disciplines such as signal processing, information theory, numerical analysis, computational physics, and computer vision. Extremely impressive progress has been made in the last several decades such as Gaussian and median filtering, Markov random field‐based filtering. To avoid the oversmoothing artifact for filtering schemes, Perona and Malik developed the now‐classic anisotropic denoising method. Thanks to Koenderink's insightful observation and other researchers' work, it was later discovered that just as Gaussian filtering is the solution to the diffusion‐type partial differential equation (PDE), the anisotropic denoising can also be put as the solution to another PDE, which aligns change rate with spatial derivative. The PDE‐based image denoising has thus received great attentions from mathematicians and computer scientists alike. In this paper, in the light of the problems of PDE‐based scheme, we first retrace the mathematics underlying the Gaussian and median filtering, then instead of working on the original image macroblocks whereof the computation of derivatives is ill‐posed, we take the Lebesgue's perspective by grouping intensity values that are neighbors to site p in value and location into a set. The median of this set then assumes the new value at p. Empirical studies suggested extremely encouraging performances by use of this simple Lebesgue anisotropic denoising method. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 64–73, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20039
Development of an infection‐resistant, bioactive wound dressing surface
Authors: Phaneuf Matthew D. , Bide Martin J. , Hannel Susan L. , Platek Michael J. , Monahan Thomas S. , Contreras Mauricio A. , Phaneuf Tina M. , LoGerfo Frank W. 
Published: July 2005

AbstractTrauma, whether caused by an accident or in an intentional manner, results in significant morbidity and mortality. The goal of this study was to develop a novel biomaterial surface in vitro and ex vivo that provides both localized infection resistance nd hemostatic properties. Our hypothesis is that a combination of specific surface characteristics can be successfully incorporated into a single biomaterial. Functional groups were created with woven Dacron (Cntrl) material via exposure to ethylenediamine (C‐EDA). The antibiotic ciprofloxacin (Cipro) was then applied to the C‐EDA material using pad/autoclave technique (C‐EDA‐AB) followed by surface immobilization of the coagulation cascade enzyme thrombin (C‐EDA‐AB‐Thrombin). Antimicrobial activity by the C‐EDA‐AB surface persisted for 5 days compared with Cntrl and dipped controls, which lasted <1 h. C‐EDA‐AB‐Thrombin surfaces had 2.6‐ and 105‐fold greater surface thrombin activity compared with nonspecifically bound thrombin and Cipro‐dyed surfaces, respectively. Surface thrombus formation ex vivo was evident after 1 min of exposure, with thrombus organization evident by 2.5 min. In contrast, C‐EDA‐AB and Cntrl segments showed only blood protein adsorption on the fibers. Thus, this study demonstrated that Cipro and thrombin can be simultaneously incorporated onto a biomaterial surface while maintaining their respective biological activities. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
A molecular mechanics force field for biologically important sterols
Authors: Cournia Zoe , Smith Jeremy C. , Ullmann G. Matthias 
Published: July 2005

AbstractA parameterization has been performed of the biologically important sterols cholesterol, ergosterol, and lanosterol for the CHARMM27 all‐atom molecular mechanics force field. An automated parameterization method was used that involves fitting the potential to vibrational frequencies and eigenvectors derived from quantum‐chemical calculations. The partial charges were derived by fitting point charges to quantum‐chemically calculated electrostatic potentials. To model the dynamics of the hydroxyl groups of the sterols correctly, the parameter set was refined to reproduce the energy barrier for the rotation of the hydroxyl group around the carbon connected to the hydroxyl of each sterol. The frequency‐matching plots show good agreement between the CHARMM and quantum chemical normal modes. The parameters are tested in a molecular dynamics simulation of the cholesterol crystal structure. The experimental geometry and cell dimensions are well reproduced. The force field derived here is also useful for simulating other sterols such as the phytosterols sigmasterol, and campesterol, and a variety of steroids. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1383–1399, 2005
MRI receiver frequency response as a contributor to Nyquist ghosting in echo planar imaging
Authors: Delakis Ioannis , Petala Krystallia , De Wilde Janet P. 
Published: July 2005

AbstractPurposeTo study the frequency response characteristic of the MRI signal receiver system as a contributing factor to the formation of Nyquist ghosting in echo‐planar imaging (EPI).Materials and MethodsExperimental work was undertaken on a 1.5 T system. A cylindrical test object filled with water was imaged axially with EPI in the center of the quadrature, transmit‐receive head coil. In the first set of experiments, the water conductivity was increased progressively with the addition of salt between EPI acquisitions. In the second set of experiments, the conductivity of the water in the test object was kept constant and EPI images were acquired at several different bandwidths. A computer simulation was also implemented to demonstrate the impact of changes in the frequency response characteristic of the signal receiver system on EPI Nyquist ghosting.ResultsExperimental and simulation results showed that Nyquist ghosting increased with the variation of the frequency response characteristic within the effective frequency range determined by the image bandwidth. One can increase the variation in the frequency response characteristic by increasing its steepness over the image's bandwidth window when coil loading is decreased, or by increasing the effective frequency range when image bandwidth is increased.ConclusionsThe results of this research may help reduce Nyquist ghosting in EPI studies when the imaging coil is not sufficiently loaded, such as in pediatric and phantom studies. J. Magn. Reson. Imaging 2005;22:324–328. © 2005 Wiley‐Liss, Inc.
Diffusion‐weighted echo‐planar MR imaging and ADC mapping in the differential diagnosis of ovarian cystic masses: Usefulness of detecting keratinoid substances in mature cystic teratomas
Authors: Nakayama Tomohiro , Yoshimitsu Kengo , Irie Hiroyuki , Aibe Hitoshi , Tajima Tsuyoshi , Nishie Akihiro , Asayama Yoshiki , Matake Kunishige , Kakihara Daisuke , Matsuura Shuji , Nakano Hitoo , Honda Hiroshi 
Published: July 2005

AbstractPurposeTo elucidate whether apparent diffusion coefficient (ADC) values calculated from echo‐planar diffusion‐weighted MR imaging (EPDWI) are useful in the differential diagnosis of ovarian cystic masses.Materials and MethodsEPDWI was performed in 131 patients with ovarian cystic masses (54 mature cystic teratomas, 35 endometrial cysts, four other benign cysts, 14 benign neoplasms, and 24 malignant neoplasms). The areas of the highest signal intensity on EPDWI (b = 1000 seconds/mm2) and the lowest ADC values within the cystic component were evaluated.ResultsOn qualitative and quantitative analyses, mature cystic teratomas tended to show higher signal intensity and had areas of lower ADC values than endometrial cysts and other benign and malignant neoplasms (P < .005). In vitro scanning of the cystic contents of mature cystic teratomas confirmed that high signal on DWI or low ADC value was attributable to the keratinoid substance within the tumors. The difference in ADC between malignant and benign lesions were significant when mature cystic teratomas and endometrial cysts were included, but was not significant when they were excluded.ConclusionThe ADC value may add useful information to the differential diagnosis of ovarian cystic masses in limited populations, such as those with mature cystic teratomas with a small amount of fat. J. Magn. Reson. Imaging 2005;22:271–278. © 2005 Wiley‐Liss, Inc.
Assessment of magnetic field (4.7 T) induced forces on prosthetic heart valves and annuloplasty rings
Authors: Edwards Maria‐Benedicta , Ordidge Roger J. , Hand Jeffrey W. , Taylor Kenneth M. , Young Ian R. 
Published: July 2005

AbstractPurposeTo assess the magnetic field interactions on 11 heart valve prostheses and 12 annuloplasty rings subjected to a 4.7 T MR system.Materials and MethodsEx vivo testing was performed to evaluate translational and rotational forces using previously described techniques.ResultsSeventeen out of 23 prostheses showed zero interaction with the magnetic field. Translational forces with deflection angles of 2–20° were demonstrated in six prostheses. Only two heart valves and two annuloplasty rings demonstrated rotational forces. The Carpentier Edwards (CE) Physio Ring, which contains Elgiloy, demonstrated deflection angles three times greater than those previously measured at 1.5 T. Furthermore, there was a direct relationship between increasing prosthesis size and increasing translational force. All heart valve prostheses attracted to the magnetic field were slightly paramagnetic/weakly ferromagnetic.ConclusionTwenty‐three heart valve prostheses evaluated for MRI are considered safe in static fields up to 4.7 T based on current safety criteria. However, the CE Physio Ring appeared to develop an increasing magnetism upon re‐entry into the MR system. We conclude that prostheses made from Elgiloy may not be acceptable for patients in an MR environment of ≥4.7 T. Further investigations are required to confirm the safety of Elgiloy. J. Magn. Reson. Imaging 2005;22:311–317. © 2005 Wiley‐Liss, Inc.
Three‐dimensional breathhold SSFP coronary MRA: A comparison between 1.5T and 3.0T
Authors: Bi Xiaoming , Deshpande Vibhas , Simonetti Orlando , Laub Gerhard , Li Debiao 
Published: July 2005

AbstractPurposeTo assess the feasibility of three‐dimensional breathhold coronary magnetic resonance angiography (MRA) at 3.0T using the steady‐state free precession (SSFP) sequence, and quantify the signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR) gains of coronary MRA from 1.5T to 3.0T using whole‐body and phased‐array cardiac coils as the signal receiver.Materials and MethodsEight healthy volunteers were scanned on 1.5T and 3.0T whole‐body systems using the SSFP sequence. Numerical simulations were performed for the SSFP sequence to optimize the flip angle and predict signal enhancement from 1.5T to 3.0T. Coronary artery images were acquired with the whole‐body coil in transmit‐receive mode or transmit‐only with phased‐array cardiac coil receivers.ResultsIn vivo studies of the same volunteer group at both field strengths showed increases of 87% in SNR and 83% in CNR from 1.5T to 3.0T using a whole‐body coil as the signal receiver. The corresponding increases using phased‐array receivers were 53% in SNR and 92% in CNR. However, image quality at 3.0T was more variable than 1.5T, with increased susceptibility artifacts and local brightening as the result of increased B0 and B1 inhomogeneities.ConclusionCoronary MRA at 3.0T using a three‐dimensional breathhold SSFP sequence is feasible. Improved SNR at 3.0T warrants the use of coronary MRA with faster acquisition and/or improved spatial resolution. Further investigations are required to improve the consistency of image quality and signal uniformity at 3.0T. J. Magn. Reson. Imaging 2005;22:206–212. © 2005 Wiley‐Liss, Inc.
Co‐registration of x‐ray and MR fields of view in a hybrid XMR system
Authors: Yu Huanzhou , Fahrig Rebecca , Pelc Norbert J. 
Published: July 2005

AbstractPurposeTo validate one possible function of a real‐time x‐ray/MR (XMR) interface in a hybrid XMR system using x‐ray images as “scouts” to prescribe the MR slices.Materials and MethodsThe registration process consists of two steps: 1) calibration, in which the system's geometric parameters are found from fiducial‐based registration; and 2) application, in which the x‐ray image of a target structure and the estimated geometric parameters are used to prescribe an MR slice to observe the target structure. Errors from the noise in the location of the fiducial markers, and MR gradient nonlinearity were studied. Computer simulations were used to provide guidelines for fiducial marker placement and tolerable error estimation. A least‐squares‐based correction method was developed to reduce errors from gradient nonlinearity.ResultsIn simulations with both sources of errors and the correction for gradient nonlinearity, the use of 16 fiducial markers yielded a mean error of about 0.4 mm over a 7200 cm3 volume. Phantom scans showed that the prescribed target slice hit most of the target line, and that the length visualized was improved with the least‐squares correction.ConclusionThe use of 16 fiducial markers to co‐register XMR FOVs can offer satisfactory accuracy in both simulations and experiments. J. Magn. Reson. Imaging 2005;22:291–301. © 2005 Wiley‐Liss, Inc.