bluuebunny/crossref_metadata_2025 huggingface dataset:
Ten Years of Judicial Gatekeeping Under Daubert
Authors: Cecil Joe S.
Published: July 2005

In the ten years since Daubert v Merrell Dow Pharmaceuticals, Inc, the standards for admissibility at trial of expert testimony in general and scientific evidence in particular have become more demanding. Reviews of recent cases and empirical studies of federal judges’ and attorneys’ practices indicate that judges are more likely to consider the admissibility of expert evidence prior to trial, to inquire more deeply into the reasoning and methodology that supports the expert opinions, and to limit or exclude such evidence from presentation at trial. Studies of published cases confirm this finding.

Recent cases consider more difficult questions arising from the differing methodologies used in various areas of science. The current legal framework that assesses admissibility in terms of professional practice outside the courtroom is poorly suited to cases that require expertise across a wide range of specialties and force judges to choose from among different scientific methodologies. Future research should focus on the pretrial screening of expert testimony and interactions between the attorneys and experts in shaping that testimony.
The Perils of Relying on Interested Parties to Evaluate Scientific Quality
Authors: Wagner Wendy
Published: July 2005

Recently, there has been a trend in both civil litigation and regulatory law to circumvent the scientific community’s collective judgment on the quality of individual studies with an adversarial process of evaluating scientific quality using interest groups. The Supreme Court’s Daubert v Merrell Dow Pharmaceuticals, Inc opinion and two recent “good science” laws passed by Congress adopt an adversarial process informed by affected parties for reviewing and screening scientific quality. These developments are unwise. Both theory and experience instruct that an adversarial, interest group–dominated approach to evaluating scientific quality will lead to the unproductive deconstruction of science, further blur the distinction between policy and scientific judgments, and result in poor decisions because the courts and agencies that preside over these “good science” contests sometimes lack the scientific competency needed to make sound decisions.
How Tobacco-Friendly Science Escapes Scrutiny in the Courtroom
Authors: Friedman Lissy C. , Daynard Richard A. , Banthin Christopher N.
Published: July 2005

Although the tobacco industry helped fund the attack on “junk science,” it has created its own dubious scientific scholarship for its expert witnesses.

We suggest that plaintiffs’ counsel should be proactive in using Daubert hearings to exclude the tobacco industry defendants’ scientific expert witnesses by introducing documentation, such as we have found through researching previously privileged internal industry documents, to prove that much of their proposed testimony was developed by and for their lawyers.
A Daubert Motion: A Legal Strategy to Exclude Essential Scientific Evidence in Toxic Tort Litigation
Authors: Melnick Ronald L.
Published: July 2005

In the US Supreme Court’s Daubert v Merrell Dow Pharmaceuticals, Inc decision, federal judges were directed to examine the scientific method underlying expert evidence and admit that which is scientifically reliable and relevant.

However, if a judge does not have adequate training or experience in dealing with scientific uncertainty, understand the full value or limit of currently used methodologies, or recognize hidden assumptions, misrepresentations of scientific data, or the strengths of scientific inferences, he or she may reach an incorrect decision on the reliability and relevance of evidence linking environmental factors to human disease.

This could lead to the unfair exclusion of valid scientific evidence, particularly that which is essential to a plaintiff’s case in toxic tort litigation.
Legal Causation and Responsibility for Causing Harm
Authors: Ozonoff David
Published: July 2005

In the legal setting, “cause” is composed of at least two distinct components, of which only one is related to “causality” as scientists understand it.

I argue that the alleged separation of the social issue of “scope of responsibility” from the objective question of scientific causality is illusory. “Scientific causality” also plays an essential social role in the legal setting.
Epistemology in the Courtroom: A Little “Knowledge” Is a Dangerous Thing
Authors: Ozonoff David
Published: July 2005

Core epistemological questions—questions about what we know, how we know it, and when we are justified in saying we know it—have a long and deep history. The US Supreme Court broached the subject in the 1993 decision Daubert v Merrell Dow Pharmaceuticals, Inc, with references to Hempel, Popper, and other scholars.

We comment here on the articles of Rothman and Greenland, who are scientists, and Haack, who is a philosopher. Their views suggest that questions of causation are neither as simple nor as difficult as many scientists and philosophers have made them.
Spatial Variability in Rainfall Erosivity versus Rainfall Depth: Implications for Sediment Yield
Authors: Hastings Brian K. , Breshears David D. , Smith Freeman M.
Published: July 2005

Rainfall depth within small semiarid watersheds can have high spatial variability, but spatial variability in rainfall erosivity, a more direct determinant of sediment yield, has not been quantified. Using 12 tipping‐bucket rain gauges within a 40‐ha piñon [Pinus edulis Engelm)–juniper (Juniperus monosperma (Engelm.) Sarg.] woodland in New Mexico, we measured rainfall erosivity (EI30) and associated precipitation and erosion metrics for 14 convective thunderstorms. Spatial variability in EI30 had a median CV across storms of 22% (range: 9–73%), exceeded the median CV for rainfall depth (15%, range: 5–26%), and varied by up to a factor of five (5–25 N h−1) within 300 m. EI30 was better correlated with sediment yield measured in <0.1‐ha microwatersheds (r2 = 0.67; p < 0.001) than rainfall depth (r2 = 0.43; p < 0.001). Our results highlight the potential importance for erosion related assessments of spatial variability in erosivity, which can be as great or greater than spatial variability in rainfall depth. The spatial variability in rainfall erosivity that we document here is relevant to erosion and contaminant transport issues near Los Alamos National Laboratory and may be applicable to other extensive semiarid areas.
Inverse Analysis of Upward Water Flow in a Groundwater Table Lysimeter
Authors: Kelleners T. J. , Soppe R. W. O. , Ayars J. E. , Šimůnek J. , Skaggs T. H.
Published: July 2005

The accuracy of numerical water flow models for the vadose zone depends on the estimation of the soil hydraulic properties. In this study, the hydraulic parameters for a silty clay soil in a large lysimeter were determined through inverse modeling of a fallow period with upward water flow from a shallow groundwater table. Parameter uniqueness was studied by simulating a hypothetical soil with known hydraulic properties under comparable conditions. Sensitivity analysis showed that the pressure head h(z,t), the volumetric water content θ(z,t), and the cumulative bottom flux Q(t) were least sensitive to the residual volumetric water content θr and the pore‐connectivity parameter λ in the van Genuchten–Mualem (VGM) model. Parameter response surfaces showed that least squares fitting with θ(z,t) data is more likely to result in a unique hydraulic parameter set than least squares fitting with h(z,t) or Q(t) data. With only θ(z,t) in the objective function, the least squares minimization algorithm was capable of finding the correct soil hydraulic parameters, provided that θr and λ were fixed and that multiple initial parameter estimates were used. The protocol that was developed for the hypothetical soil was subsequently applied to the actual groundwater table lysimeter. The soil hydraulic parameters for the lysimeter for two (x,y) locations were determined using θ(z,t) data as measured by capacitance sensors. The variability in the optimized inverse of the air‐entry value α and the saturated hydraulic conductivity Ks in the VGM model was relatively high because of the high parameter correlation between these parameters. The optimized soil hydraulic properties can be used to study capillary rise from the groundwater table.
Water and Solute Transport in a Cultivated Silt Loam Soil: 2. Numerical Analysis
Authors: Coquet Y. , Šimůnek J. , Coutadeur C. , van Genuchten M. Th. , Pot V. , Roger‐Estrade J.
Published: July 2005

A field experiment was performed to study the effects of soil structure heterogeneity generated by farming practices (i.e., compaction by wheel traffic, plowing, surface tillage) on plot‐scale water flow and solute transport. The experiment involved a 4 by 2 m2 field plot that was uniformly sprinkle irrigated with water and bromide for about 6 h. Independently measured soil hydraulic functions were used to simulate the experiment with a numerical flow and transport model (HYDRUS‐2D) using a fully deterministic approach for describing soil heterogeneity. The numerical model reproduced observed flow and transport processes only after adjustments were made to the soil hydraulic functions. Adjustments were needed to account for increased flow and transport into and through the soil between the compacted zones below the wheel tracks, and to predict double concentration peaks caused by the umbrella (or shadow) effects of compacted soil clods. Global optimization of the soil hydraulic parameters produced a satisfactory description of the very heterogeneous flow patterns, with the resulting hydraulic parameters showing only limited correlation among each other. We demonstrate that double‐peak concentration profiles can result from the presence of tillage‐induced soil heterogeneities.
Banded gas and nongray surface radiation models for high‐emissivity coatings
Authors: Heynderickx Geraldine J. , Nozawa Masatsugu
Published: July 2005

The efficiency of the application of high‐emissivity coatings on reactor tubes and furnace walls in steam‐cracking technology can be evaluated only on the basis of a description of radiative heat transfer in frequency bands. For the flue gases in the furnace, a radiation model is introduced in which the gas emits and absorbs radiation in discrete bands only; for the surfaces a nongray surface approach is applied. First, the influence of the model changes on the calculated radiative energy exchange is evaluated theoretically. Next, different furnace simulations are performed to do a numerical evaluation of the introduction of banded radiation models. The changes in the furnace thermal efficiency, attributed to the application of high‐emissivity coatings on furnace walls and tube skins in steam‐cracking furnaces, are calculated. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Functional‐cranial approach to the influence of economic strategy on skull morphology
Authors: González‐José Rolando , Ramírez‐Rozzi Fernando , Sardi Marina , Martínez‐Abadías Neus , Hernández Miquel , Pucciarelli Hector M.
Published: July 2005

Environmental factors are assumed to play an important role in the shaping of craniofacial morphology. Here we propose a statistical approach which can be of utility in estimating the magnitude and localization of a particular nongenetic factor upon the specific functional components of the skull. Our analysis is a combination of previous attempts of apportionment of variance and the application of craniofunctional theory. The effect of subsistence strategy on craniofacial functional components was studied on 18 populations of hunter‐gatherers and farmers from South America. Results demonstrate that the environmental factors studied likely influenced the masticatory component's size and shape. Even when this effect is not large enough to clearly differentiate among subsistence strategies (since whole craniofacial variation among populations remains greater), the method used here provides interesting clues to localize plastic or adaptive responses to external stimuli. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Late Pleistocene/Holocene craniofacial morphology in Mesoamerican Paleoindians: Implications for the peopling of the New World
Authors: González‐José Rolando , Neves Walter , Lahr Marta Mirazón , González Silvia , Pucciarelli Héctor , Martínez Miquel Hernández , Correal Gonzalo
Published: July 2005

Several studies on craniofacial morphology showed that most Paleoindians, who were the first settlers of the New World, clearly differ from modern Amerindians and East Asians, their supposed descendants and sister group, respectively. Here we present new evidence supporting this view from the Late Pleistocene/Early Holocene horizon from Mexico, as well as from the most complete set of dated Paleoindian remains. We analyzed the phenotypic resemblance of early Mexicans with other South Paleoamerican and modern human series. Two independent approaches to the data were used. In the first case, individual specimens were tested for morphological similarity with a set of modern reference samples. In the second analysis, Mexican specimens were treated as a sample in order to compute minimum genetic distances. Results from both approaches tend to associate early Mexican skulls with Paleoindians from Brazil, an Archaic sample from Colombia, and several circum‐Pacific populations. These results give support to a model in which morphologically generalized groups of non‐Northeast Asian descent (the so‐called Paleoamericans) entered the continent first, and then dispersed from North to South America through Central America. The large geographic dispersal of Paleoamericans, and their presence in Mexico in the Early Holocene, raise new issues about the continent's settlement scenario. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Strategien für die Wasserstoffspeicherung in metall‐organischen Kompositgerüsten
Authors: Rowsell Jesse L. C. , Yaghi Omar M.
Published: July 2005

Metall‐organische Gerüste finden verstärkt Interesse als mögliche Materialien zur Wasserstoffspeicherung. Hintergrund dieser Forschungen sind die zahlreichen herausragenden Merkmale dieser Substanzen – wie hohe Porosität, reproduzierbare und einfache Synthesen, leichte Skalierbarkeit und die Möglichkeit zur gezielten chemischen Modifizierung zur Einstellung gewünschter Eigenschaften. Dieser Kurzaufsatz diskutiert Strategien zur Verbesserung der Wasserstoffaufnahme durch metall‐organische Gerüste. Die Ansätze umfassen die Optimierung der Porengröße und Adsorptionsenergien durch Modifizierung von Linkern, durch Imprägnierung und Catenierung sowie durch den Einbau von koordinativ ungesättigten Metallzentren und Leichtmetallen.
Titelbild: Strategien für die Wasserstoffspeicherung in metall‐organischen Kompositgerüsten / High H2 Adsorption in a Microporous Metal–Organic Framework with Open Metal Sites (Angew. Chem. 30/2005)
Authors: Rowsell Jesse L. C. , Yaghi Omar M. , Chen Banglin , Ockwig Nathan W. , Millward Andrew R. , Contreras Damacio S.
Published: July 2005

Wasserstoffspeichermaterialien auf der Basis metall‐organischer Gerüste sind wegen der herausragenden Eigenschaften dieser Substanzen (große effektive Oberflächen und Porenvolumina, einfache Synthese und Funktionalisierung, Skalierbarkeit) in den Blickpunkt der Materialwissenschaften gerückt. Im Kurzaufsatz auf S. 4748 ff. diskutieren O. M. Yaghi und J. L. C. Rowsell Strategien zur Optimierung von Porosität und Porengröße für die Speicherung von Wasserstoff unter Umgebungsbedingungen. Ein vielversprechendes Wasserstoffspeichermaterial mit koordinativ ungesättigten Metallzentren wird außerdem von B. Chen, O. M. Yaghi et al. in der Zuschrift auf S. 4823 ff. vorgestellt.
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

High‐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

The 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

As 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

Members 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

T1 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

Capturing 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

This 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

The 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

Trauma, 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

A 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

Purpose

To 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 Methods

Experimental 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.

Results

Experimental 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.

Conclusions

The 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

Purpose

To 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 Methods

EPDWI 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.

Results

On 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.

Conclusion

The 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

Purpose

To assess the magnetic field interactions on 11 heart valve prostheses and 12 annuloplasty rings subjected to a 4.7 T MR system.

Materials and Methods

Ex vivo testing was performed to evaluate translational and rotational forces using previously described techniques.

Results

Seventeen 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.

Conclusion

Twenty‐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

Purpose

To 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 Methods

Eight 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.

Results

In 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.

Conclusion

Coronary 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

Purpose

To 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 Methods

The 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.

Results

In 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.

Conclusion

The 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.
Depth‐dependent proton magnetization transfer in articular cartilage
Authors: Regatte Ravinder R. , Akella Sarma V.S. , Reddy Ravinder
Published: July 2005

Purpose

To measure the proton magnetization transfer ratio (MTR) maps in control and collagen‐depleted bovine patellar cartilage specimens as a function of cartilage depth during mechanical compression.

Materials and Methods

One‐dimensional proton projection MR images employing a spin‐echo imaging sequence were obtained on a custom‐built NMR spectrometer interfaced to an Oxford magnet operating at 2T. The mechanical compressions were performed with a custom‐built MR‐compatible pressure cell and evaluated dynamically via one‐dimensional projection. High‐spatial‐resolution two‐dimensional MT images were obtained using a fast spin‐echo (FSE) sequence on a 4T whole‐body GE Signa scanner (GEMS, Milwaukee, WI, USA) to quantify the MTR maps of normal and collagen‐depleted bovine patellae.

Results

All of the cartilage plugs from the bovine patellae showed that the MTR value increases continuously as a function of cartilage depth. Although the overall MTR trend as a function of depth is the same in both control and collagen‐depleted cartilage, the magnitude of the MTR value differs between the two. The MTR value is decreased with collagen depletion and increased with mechanical compression. The increase in MTR value during compression may be due to a decrease in free water content and volume, resulting in an increase in collagen concentration.

Conclusion

We demonstrated that the MTR in bovine patellar cartilage is depth‐dependent and is relatively higher in the radial zone compared to the superficial zone. The high MTR in the radial zone not only depends on collagen content, it may also reflect a number of other parameters, such as the arrangement of macromolecules, high solid content, bound water fraction attached to macromolecules, radial orientation, etc. J. Magn. Reson. Imaging 2005;22:318–323. © 2005 Wiley‐Liss, Inc.
Diffusion tensor imaging of the human optic nerve using a non‐CPMG fast spin echo sequence
Authors: Chabert Steren , Molko Nicolas , Cointepas Yann , Le Roux Patrick , Le Bihan Denis
Published: July 2005

Purpose

To investigate the diffusion tensor properties of the human optic nerve in vivo using a non‐Carr‐Purcell‐Meiboom‐Gill (CPMG) fast spin echo (FSE) sequence.

Materials and Methods

This non‐CPMG FSE sequence, which is based on a quadratic phase modulation of the refocusing pulses, allows diffusion measures to be acquired with full signal and without artifacts from geometric distortions due to magnetic field inhomogeneities, which are among the main problems encountered in the orbital area.

Results

Good‐quality images were obtained at a resolution of 0.94 × 0.94 × 3 mm. The mean diffusivity (MD) and fractional anisotropy (FA) were respectively 1.1 ± 0.2 × 10–3 mm2/second and 0.49 ± 0.06, reflecting the optic nerve anisotropy.

Conclusion

This non‐CPMG‐FSE sequence provides reliable diffusion‐weighted images of the human optic nerve. This approach could potentially improve the diagnosis and management of optic nerve diseases or compression, such as optic neuritis, orbit tumors, and muscle hypertrophy. J. Magn. Reson. Imaging 2005;22:307–310. © 2005 Wiley‐Liss, Inc.
Oral contraceptives and uterine peristalsis: Evaluation with MRI
Authors: Kido Aki , Togashi Kaori , Nakai Asako , Kataoka Milliam L. , Koyama Takashi , Fujii Shingo
Published: July 2005

Purpose

To evaluate the effects of oral contraceptives (OCs) on uterine contractility using cine MRI, and correlate the kinematic findings with the static findings.

Materials and Methods

Healthy female volunteers of reproductive age (23 taking OCs, and 15 not) were evaluated at mid‐cycle. MR images were obtained with a 1.5T magnet, with 60 serial images taken every three seconds by half‐Fourier acquisition single‐shot turbo spin echo (HASTE) to be displayed in cine mode. Assessments were based on the 1) detectability of uterine peristalsis in cine mode, 2) peristaltic frequency and direction, 3) thickness of the endometrium, myometrium, and junctional zone (JZ) on T2‐weighted images (T2WIs), and 4) intensity of the myometrium and cervical mucus on T2WIs and T1‐weighted images (T1WIs), respectively.

Results

Uterine peristalsis was markedly decreased in the OC users. The endometrium and JZ were significantly thinner, and the myometrium was thicker in the OC users compared to controls. The signal intensity of the myometrium and cervical mucus was significantly higher in the OC users than in controls.

Conclusion

OCs markedly suppressed uterine peristalsis at mid‐cycle, and the uterus displayed a globular configuration with a thin JZ that may be related to decreased uterine peristalsis in OC users. J. Magn. Reson. Imaging 2005;22:265–270. © 2005 Wiley‐Liss, Inc.
Identification of Brucella species isolated from proven brucellosis patients in Izmir, Turkey
Authors: Köse Şükran , Kiliç Selçuk , Özbel Yusuf
Published: July 2005

In many parts of the world, brucellosis has significantly decreased, but it is still a problem in some regions of Turkey. Totally, 11 Brucella strains isolated from the blood cultures of patients with presumptive diagnosis of brucellosis were identified to species and biovar level. For species identification, (i) CO2 requirements of isolates; (ii) detection of urease activation; (iii) detection of H2S production; (iv) dye sensitivities (thionine and basic fuchsin); (v) susceptibility to Brucella phage and (vi) agglutination with monospecific antisera (A and M) were performed. Ten out of 11 isolates were identified as B. melitensis biovar 3 and one out of 11 were identified as B. melitensis biovar 1. The sensitivity of isolates to antibiotics was determined by the E‐test. All isolates were found to be sensitive to doxycycline, rifampin, ciprofloxacin and cephtriaxone. Only one out of 11 isolates was found to be semi‐sensitive to trimethoprim/sulfamethoxazole (cotrimoxazole). (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rock glaciers in the northern Japanese Alps: palaeoenvironmental implications since the Late Glacial
Authors: Aoyama Masafumi
Published: July 2005

In order to determine the palaeoclimatic and palaeo‐permafrost conditions in the northern Japanese Alps in central Japan, the ages of rock glaciers were investigated by relative age dating techniques such as weathering‐rind thickness and Schmidt hammer measurements. The results of the relative age dating suggest that the formation of the investigated rock glaciers may have started during the early phase of the Late Glacial or around the onset of the Holocene. The lower limit of current discontinuous permafrost in the northern Japanese Alps, which is indicated by the terminus of the lowest active/inactive rock glacier, lies at 2530 m a.s.l., while that of discontinuous permafrost during the Late Glacial or early phase of the Holocene, which is indicated by the terminus of the lowest relict rock glacier, lies at 2220 m a.s.l. Therefore, the lower limit of discontinuous permafrost during these periods would have been at least about 300 m lower than that of the current discontinuous permafrost. Climatic and geomorphological conditions during the Late Glacial led to a change in the environment from a glacial environment to a periglacial (permafrost) environment in the current alpine zone of the northern Japanese Alps. A large number of cirques were deglaciated and several of them were occupied by active rock glaciers around the onset of the Holocene. Copyright © 2005 John Wiley & Sons, Ltd.
Amplitude of ENSO cycles in the Santa Barbara Basin, off California, during the past 15 000 years
Authors: Nederbragt Alexandra J. , Thurow Jürgen
Published: July 2005

Varve thickness time series from ODP Site 893 in the Santa Barbara Basin (off California) were analysed to determine variation in the strength of El Niño/Southern Oscillation (ENSO) cycles during the past 15 000 yr. Mean varve thickness and variance changed over time, with thicker varves before ∼8000 yr BP indicative of wetter than modern climates. A 100‐yr running standardisation was applied to correct for non‐stationarity. The contribution of ENSO‐scale variability was then estimated as the amplitude of 3–8 year bandpassed data. Results show multidecadal‐ to centennial‐scale modulation of the amplitude. On average, however, the amplitude of ENSO scale variability remained constant throughout the past 15 000 yr. We therefore conclude that, although the expression of ENSO cycles may have changed during the Holocene, there is no indication for a significant change in amplitude of interannual variability. Copyright © 2005 John Wiley & Sons, Ltd.
Utilization of zirconia stationary phase as a tool in drug control
Authors: Kučera Radim , Žižkovský Václav , Sochor Jaroslav , Klimeš Jiří , Dohnal Jiří
Published: July 2005

Zirconia‐based stationary phases represent an interesting alternative to silica‐based materials. Two zirconia‐based stationary phases were studied as an option for use in drug analysis. The different properties of zirconia material, distinct from RP silica‐columns, were employed for the development of a novel and rapid stability monitoring HPLC method. This method enables simultaneous control of possible degradation processes of active substance (ibuprofen) as well as antimicrobial excipients (methyl‐ and propylparaben). The separation of ibuprofen, its two main degradation products 2‐(4‐isobutyrylphenyl)propionic acid and 4‐isobutylacetophenone, parabens, and 4‐hydroxybenzoic acid as their degradation product was successfully accomplished on a Zr‐CarbonC18 column using a mobile phase consisting of acetonitrile‐phosphate buffer (pH 4.8)‐propan‐2‐ol (27 : 56:17, v/v/v). Detection was performed at 258 nm and the analysis was completed within 17 minutes.
Pyramidal tract imaging in multiple‐system atrophy
Authors: Limberg Nicole , Jeavons Susanne , Robertson Thomas , Boyle Richard
Published: July 2005

A new radiological finding of T2 FLAIR hyperintensities in the pyramidal tracts is described in a patient clinically thought to have idiopathic Parkinson's disease but histologically proven to have multiple‐system atrophy. © 2005 Movement Disorder Society