bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Post Hoc Power in Testing Mean Differences
Authors: Yuan Ke-Hai , Maxwell Scott
Published: June 2007

Retrospective or post hoc power analysis is recommended by reviewers and editors of many journals. Little literature has been found that gave a serious study of the post hoc power. When the sample size is large, the observed effect size is a good estimator of the true effect size. One would hope that the post hoc power is also a good estimator of the true power. This article studies whether such a power estimator provides valuable information about the true power.

Using analytical, numerical, and Monte Carlo approaches, our results show that the estimated power does not provide useful information when the true power is small. It is almost always a biased estimator of the true power. The bias can be negative or positive. Large sample size alone does not guarantee the post hoc power to be a good estimator of the true power. Actually, when the population variance is known, the cumulative distribution function of the post hoc power is solely a function of the population power. This distribution is uniform when the true power equals 0.5 and highly skewed when the true power is near 0 or 1. When the population variance is unknown, the post hoc power behaves essentially the same as when the variance is known.
Bias and Efficiency of Meta-Analytic Variance Estimators in the Random-Effects Model
Authors: Viechtbauer Wolfgang
Published: June 2007

The meta-analytic random effects model assumes that the variability in effect size estimates drawn from a set of studies can be decomposed into two parts: heterogeneity due to random population effects and sampling variance. In this context, the usual goal is to estimate the central tendency and the amount of heterogeneity in the population effect sizes. The amount of heterogeneity in a set of effect sizes has implications regarding the interpretation of the meta-analytic findings and often serves as an indicator for the presence of potential moderator variables. Five population heterogeneity estimators were compared in this article analytically and via Monte Carlo simulations with respect to their bias and efficiency.
Pitfalls in Pathways: Some Perspectives on Competing Risks Event History Analysis in Education Research
Authors: Scott Marc A. , Kennedy Benjamin B.
Published: June 2007

A set of discrete-time methods for competing risks event history analysis is presented. The approach used is accessible to the practitioner and the article describes the strengths, weaknesses, and interpretation of both exploratory and model-based tools. These techniques are applied to the impact of “nontraditional” enrollment features (working, stopout, and delayed enrollment) on competing outcomes of sub-baccalaureate enrollment (degree attainment, transfer, and dropout). In this setting, model selection, estimation, and comparative inference are discussed and more general guidelines for each stage of analysis are provided. Substantively, the study finds that nontraditional enrollment features are associated with dramatic changes in expected outcomes.
Interval Estimation for True Raw and Scale Scores Under the Binomial Error Model
Authors: Lee Won-Chan , Brennan Robert L. , Kolen Michael J.
Published: June 2007

Assuming errors of measurement are distributed binomially, this article reviews various procedures for constructing an interval for an individual’s true number-correct score; presents two general interval estimation procedures for an individual’s true scale score (i.e., normal approximation and endpoints conversion methods); compares various interval estimation procedures through a computer simulation study; and provides some practical guidelines for use of the interval estimation procedures. To examine the effects of different types of scale scores, three nonlinearly transformed scale scores are employed. The conditional confidence intervals using conditional standard errors of measurement are recommended over the traditional confidence intervals using the overall standard error of measurement. For raw scores, the score confidence intervals, in general, tend to provide actual coverage probabilities that are closest to the nominal level. Results for scale score intervals seem to favor the endpoints conversion method using the true-score conversions over the normal approximation approach.
You've Come a Long Way, Baby? Persistent Gender Inequality in University Enrolment and Completion in Canada, 1979–2004
Authors: Andres Lesley , Adamuti-Trache Maria
Published: June 2007

We examine 25 years of Statistics Canada data on university undergraduate enrolment and gradation rates from 1979 to 2004 by employing field-specific indices of association that measure the under- or overrepresentation of women in a particular field relative to the gender composition in all fields. Our findings reveal patterns of convergence and divergence but, most consistently, of steadiness with respect to gender integration. An overall index of association for undergraduate enrolment indicates that over 25 years gender segregation has decreased by only 5 percent. The comparable figure for degree completion is 13 percent. Spectacular increases in enrolment and completion by women have not been translated into gender integration within most fields of study, suggesting that different structures of opportunities within higher education continue to perpetuate gender inequities in the labour market.
Boolean Functions
Authors: Mc Crosky Carl D. , Wang Yuke
Published: June 2007

Boolean functions
and the underlying
Boolean algebra
are an essential mathematical foundation of digital technology. Nearly all technological applications that involve representation, manipulation, communication, or storage of information are built on this foundation. Examples include computers; telecommunications networks; music, game, photography, and video devices; and control systems in a myriad of products such as automobiles, industrial equipment, and banking machines.

Introduction

History of Mathematical Development

Definition of Boolean Algebra

Language of Boolean Algebra Statements

Axioms and Theorems

Proofs

Reduction

Closed and Complete

Additional Syntaxes and Omitted Parentheses

Definition of Functions

Cartesian Products and Boolean Cubes

Functions of

Truth Tables

Canonical Representations (
SOP
and
POS
)

Minimization

Cycles of Canonical Representations

Nested Logic Forms

Logic Gates

Switching Circuits

Complements and Restrictions

Data Structures for Boolean Functions

Algorithms for Boolean Functions

Classification of Boolean Functions

Standard Boolean Functions

Implementations of Boolean Functions

Computer Aided Design

State Machines
Fuzzy Image Processing and Recognition
Authors: Pal Sankar K.
Published: June 2007

This article describes various fuzzy set theoretic tools and explores their effectiveness in representing/describing various uncertainties that might occur in an image recognition system and the ways these uncertainties can be managed in making a decision. Some examples of uncertainties that often develop in the process of recognizing a pattern are given in the next section. The Image Ambiguity and Uncertainty Measures Section provides a definition of image and describes various fuzzy set theoretic tools for measuring information on grayness ambiguity and spatial ambiguity in an image. Concepts of bound functions and spect sets charactering the flexible in membership functions are discussed in Their applications to formulate some low level vision operations (e.g., enhancement, segmentation, skeleton extraction, and edge detection), whose outputs are crucial and responsible for the overall performance of a vision system, are then presented. Some real‐life applications (e.g., motion frame analysis, character recognition, remote sensing image analysis, content‐based image retrieval, and brain MR image segmentation) of these methodologies and tools are then described. Finally, conclusions and discussion are provided.

Introduction

Uncertainties in a Recognition System and Relevance of Fuzzy Set Theory

Image Ambiguity and Uncertainty Measures

Grayness Ambiguity Measures

Flexibility in Membership Functions

Some Examples of Fuzzy Image Processing Operations

Some Applications

Conclusions and Discussion

Acknowledgment
NOS‐I and ‐III gene variants are differentially associated with facets of suicidal behavior and aggression‐related traits
Authors: Rujescu Dan , Giegling Ina , Mandelli Laura , Schneider Barbara , Hartmann Annette M. , Schnabel Axel , Maurer Konrad , Möller Hans‐Jürgen , Serretti Alessandro
Published: June 2007

Nitric oxide (NO) is a neurotransmitter which modulates depressive and aggressive behaviors. We studied gene variants of NOS‐I (rs2682826;rs1353939;rs2293049;rs693534) and NOS‐III (rs2070744;rs1799983;rs891512) in a total of 571 cases (167 German suicide attempters, 92 Caucasian suicide completers and 312 German healthy subjects). A NOS‐I risk haplotype C‐G‐G (rs2682826‐rs1353939‐rs693534) was associated with suicidal behavior (P = 0.01), and more specifically with suicide attempts (P = 0.01). Sliding windows analysis showed similar results for the haplotype G‐G (rs1353939‐rs693534) being a risk factor for suicidal behavior (P = 0.01) again especially in suicide attempters (P = 0.004). Additionally, the G‐allele of rs693534 was associated with suicidal behavior (P = 0.005) and more specifically with suicide attempts (P = 0.003). Interestingly, the same haplotype (G‐G) as well as the rs693534 G‐allele were also associated with increased aggression. Regarding NOS‐III, a protective haplotype C‐T‐A (rs2070744‐rs1799983‐rs891512) was observed (P = 0.01) with a pronounced effect against suicide completion (P = 0.005). Sliding window analysis showed the same effect of haplotype T‐A (rs1799983–rs891512) (P = 0.01) which was again protective against suicide completion (P = 0.006). Single marker analysis showed the same protective effect of the rs891512 A‐allele (P = 0.009) again especially against suicide completion (P = 0.007). Additionally, a second haplotype (T‐T‐G) was associated with increased aggression (P = 0.0002; sliding haplotype T‐G, P = 0.002). In conclusion, our study suggests a possible involvement of NOS‐I and NOS‐III gene variants in suicidal behavior and related intermediate phenotypes. © 2007 Wiley‐Liss, Inc.
Elektrospinnen: eine faszinierende Methode zur Präparation ultradünner Fasern
Authors: Greiner Andreas , Wendorff Joachim H.
Published: June 2007

Das Elektrospinnen ist eine vielseitige Methode, um aus Lösungen und Schmelzen, vorwiegend von Polymeren, kontinuierliche Fasern mit Durchmessern von wenigen Mikrometern bis zu wenigen Nanometern herzustellen. Die Methode ist vielseitig anwendbar, da sich nahezu alle löslichen und schmelzbaren Polymere einsetzen lassen, die Polymere außerdem mit unterschiedlichsten Additiven – von einfachen Rußpartikeln bis zu komplexen Spezies wie Enzymen, Viren und Bakterien – ausgerüstet werden können und natürlich auch chemische Modifikationen möglich sind. Die Methode des Elektrospinnens erscheint einfach, ist aber ein äußerst komplexer Vorgang, der von einer Vielzahl von molekularen, Prozess‐ und apparativen Parametern beeinflusst wird, was natürlich auch Möglichkeiten für vollkommen neuartige Materialien mit komplexem chemischem Aufbau bietet. Das Elektrospinnen ist nicht nur eine Methode, die derzeit intensiv erforscht wird, sie findet auch bereits Anwendungen in vielen technischen Bereichen.
Polyferrocenylsilane‐Based Polymer Systems
Authors: Bellas Vasilios , Rehahn Matthias
Published: June 2007

The study of metallopolymers has blossomed into a mature field over the last few decades. Especially, polyferrocenylsilane (PFS) chemistry has taken a tremendous leap and continues to raise intense interest. Since the discovery of thermal ring‐opening polymerization (ROP) of sila[1]ferrocenophanes, PFSs have been also accessed by anionic, cationic, transition‐metal‐catalyzed, and photolytic anionic ROP methodologies. A plethora of synthetic strategies have been devised, enabling access to a wide variety of copolymers, polyelectrolytes, and nanostructured materials. The distinctive physical properties and functions of many PFS‐based polymers have been explored, leading to their apt exploitation in technical applications. Therefore, it is conceivable that PFS‐related platforms might be indispensable nano‐objects in the near future, as they stand on the verge of a new generation of sophisticated materials.
Reduction of boundary effects in the spiralMRI experiment PROMISE
Authors: Szklarski J.
Published: June 2007

Magnetorotational instability (MRI) is one of the most important and most common instabilities in astrophysics. It is widely accepted that it serves as a source of turbulent viscosity in accretion disks – the most energy efficient objects in the Universe. However it is very difficult to bring this process down on earth and model it in a laboratory experiment. Several different approaches have been proposed, one of the most recent is PROMISE (Potsdam‐ROssendorf Magnetorotational InStability Experiment). It consists of a flow of a liquid metal between two rotating cylinders under applied current‐free spiral magnetic field. The cylinders must be covered with plates which introduce additional end‐effects which alter the flow and make it more difficult to clearly distinguish between MRI stable and unstable state. In this paper we propose simple and inexpensive improvement to the PROMISE experiment which would reduce those undesirable effects. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Telescope and instrument robotization at Dome C
Authors: Strassmeier K. G. , Agabi K. , Agnoletto L. , Allan A. , Andersen M. I. , Ansorge W. , Bortoletto F. , Briguglio R. , Buey J.‐T. , Castellini S. , Coudé du Foresto V. , Damé L. , Deeg H. J. , Eiroa C. , Durand G. , Fappani D. , Frezzotti M. , Granzer T. , Gröschke A. , Kärcher H. J. , Lenzen R. , Mancini A. , Montanari C. , Mora A. , Pierre A. , Pirnay O. , Roncella F. , Schmider F.‐X. , Steele I. , Storey J. W. V. , Tothill N. F. H. , Travouillon T. , Vittuari L. , Weber M.
Published: June 2007

This article reviews the situation for robotization of telescopes and instruments at the Antarctic station Concordia on Dome C. A brain‐storming meeting was held in Tenerife in March 2007 from which this review emerged.We describe and summarize the challenges for night‐time operations of various astronomical experiments at conditions “between Earth and Space” and conclude that robotization is likely a prerequisite for continuous astronomical data taking during the 2000‐hour night at Dome C. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pore‐Forming Properties of Alamethicin F50/5 Inserted in a Biological Membrane
Authors: Vedovato Natascia , Baldini Chiara , Toniolo Claudio , Rispoli Giorgio
Published: June 2007

The pore‐forming properties of native and synthetic alamethicins were investigated in photoreceptor rod outer segments (OS) isolated from frog retina, and recorded in whole‐cell configuration. The peptaibols were applied (and removed) to (from) the OS within less than 50 ms by means of a computer‐controlled micro‐perfusion system. Once blocked with light, the main OS endogenous conductance, the OS membrane resistance was >1 GΩ, allowing low‐noise and high‐resolution recordings. Currents of ca. 700 pA were recorded in symmetric K+ (100 mM) and Ca2+ (1 mM), upon applying 1 μM of alamethicin F50/5 or its [L‐Glu(OMe)7,18,19] analogue to the OS membrane (clamped at −20 mV). In the latter peptide, the Gln residues at positions 7, 18, and 19 were substituted with side‐chain esterified Glu residues. For both peptides, the current activated exponentially, with a delay from peptide application, and exponentially returned to zero without any delay, upon removing the peptide from the external solution. The delay as well as the activation (τa) and deactivation (τd) time constants of the current produced by the modified alamethicin were much slower, and the current noise was much larger, with respect to the corresponding values for alamethicin F50/5. Therefore, the above three Gln residues are not a key factor for pore formation, but the [L‐Glu(OMe)7,18,19] analogue produces larger pores with a lower probability of formation.
Prostate cancer laterality as a rationale of focal ablative therapy for the treatment of clinically localized prostate cancer
Authors: Mouraviev Vladimir , Mayes Janice M. , Sun Leon , Madden John F. , Moul Judd W. , Polascik Thomas J.
Published: June 2007

BACKGROUND.

Early detection of small‐volume prostate cancer (PCa) has led to the concept of focal therapy to treat PCa as an organ‐sparing, minimally invasive procedure. The authors sought to determine the frequency of unilateral cancers in the contemporary prostate‐specific antigen (PSA) era to determine the percentage of patients who would be candidates for hemiablation of the prostate by using focal therapy while preserving the contralateral lobe.

METHODS.

Paraffin‐embedded radical prostatectomy specimens (1184 specimens) from consecutive patients between 2002 and 2006 with pathologic organ confined PCa were analyzed. Pathologic assessment focused on tumor laterality and percentage of tumor involvement (PTI) along with other routine parameters such as pathological T‐classification (pT), pathological Gleason Score (pGS), extracapsular extension (ECE), and surgical margins (SM). Clinical and pathologic parameters were analyzed by univariate and multivariate methods.

RESULTS.

Completely unilateral cancers were identified in 227 (19.2%) of 1184 patients. Of these patients, 164 (72.2%) had PTI of ≤5%, 40 (17.6%) had a PTI of 5.01%–10%, 9 (4.0%) had a PTI of 10.01%–15%, and 14 (6.2%) had a PTI of > 15%, respectively (P < .0005). African‐American men had bilateral cancers more commonly that non‐African‐American men, eg, 90.8% versus 79.2%, respectively (P < .0005). Race, PTI, pGS, and SM were independent predictors by multivariate logistic regression (P ≤ .05).

CONCLUSIONS.

This study suggests that 1 in 5 men diagnosed with PCa have small volume, completely unilateral cancers that may be amenable to hemiablation of the prostate. Further study is needed to develop predictive models to select candidates for focal therapy. Cancer 2007; 110:906–10. © 2007 American Cancer Society.
Role of fine‐needle aspirate immunophenotyping by flow cytometry in rapid diagnosis of lymphoproliferative disorders
Authors: Gupta Ritu , Naseem Shano , Kashyap Rajesh , Paul Lily
Published: June 2007

Immunophenotyping is an essential component in the diagnostic work‐up of lymphoproliferative disorders (LPD). As compared to immunohistochemistry, flow cytometric immunophenotyping (FCMI) is rapid, quantitative and a more objective technique. This study was designed to evaluate the utility of FCMI on fine needle aspirates (FNA) in rapid diagnosis of LPD in routine clinical practice. FNA from 31 consecutive cases clinically suggestive of LPD were subjected to FCMI. Representative material for FCMI was obtained in 28 (90%) cases and a definite diagnosis established in 27 cases. Histopathogical correlation was available in 22 cases and concordance with FCMI results was observed in 19 (86.4%) cases. FCMI analysis was inconclusive in 4 cases. The results of FCMI were available the same day and were crucial for therapeutic purpose in 3 patients with superior vena cava syndrome. FCMI combined with cytological examination of aspirate smears permits rapid diagnosis with high level of accuracy resulting in efficient treatment planning for critically ill patients and those from far‐off rural areas. Diagn. Cytopathol. 2007;35:381–385. © 2007 Wiley‐Liss, Inc.
Immune modulation of HLA‐G dimer in maternal‐fetal interface
Authors: Kuroki Kimiko , Maenaka Katsumi
Published: June 2007

HLA‐G is a non‐classical human MHC class I molecule, which has several characteristics distinct from classical MHC, such as low polymorphism and restricted tissue distribution. HLA‐G is expressed on placenta, thymus and some tumors. At the maternal‐fetal interface, trophoblasts do not express major classical MHC class I molecules (MHCI), HLA‐A and ‐B, to prevent normal T cell responses. Instead, HLA‐G is expressed and can suppress a wide range of immune responses by binding to inhibitory immune cell surface receptors, such as leukocyte Ig‐like receptor (LILR) B1 and LILRB2. HLA‐G exists in various forms, including β2m‐associated or ‐free disulfide‐linked dimers that can be expressed either at the cell surface or in soluble form. However, until recently the physiological role of these different molecular forms has been unclear. In this issue of the European Journal of Immunology, one article demonstrates that the disulfide‐linked homodimer of β2m‐associated HLA‐G is the major fraction expressed by trophoblast cells. The HLA‐G dimer modulates the function of LILRB1‐expressing antigen‐presenting cells by principally binding to LILRB1. On the other hand, another recent report showed that β2m‐free disulfide‐linked HLA‐G dimers are produced by villous cytotrophoblast cells. Taken together, these results provide strong evidence in support of the hypothesis that HLA‐G dimers play a role in immune suppression at the maternal‐fetal interface. Further in‐depth investigation will help to clarify the precise mechanism of HLA‐G receptor recognition and signaling in vivo and the role of these interactions in successful reproduction.

See accompanying article: http://dx.doi.org/10.1002/eji.200737089
Effects of forage species and stage of maturity on bovine milk fatty acid composition
Authors: Vanhatalo Aila , Kuoppala Kaisa , Toivonen Vesa , Shingfield Kevin J.
Published: June 2007

Five cows were used in a 5×5 Latin square to evaluate the effects of forage type and stage of herbage maturity on milk fatty acid (FA) composition. Four silages were prepared from primary growths of timothy‐meadow fescue and red clover swards at an early and late stage of growth. Treatments consisted of these silages and an additional treatment comprised of an equal mixture of late‐cut grass silage and early‐cut red clover silage. Forages were fedad libitumand supplemented with 9 kg/day of a standard concentrate. Compared with grass silage, red clover silage diets enhanced milk fat monounsaturated FA (MUFA) and polyunsaturated FA (PUFA) content, 18:3 n‐3 in particular, responses that were associated with concomitant reductions in 10:0 to 16:0 concentrations. Decreases in 16:0 and increases in PUFA concentrations were more pronounced for early than late growths of red clover. Even though red clover resulted in marginal increases in total milk fattrans18:1 content, milktrans‐11 18:1 concentrations were lower for red clover than for grass silage diets. It is concluded that replacing grass with red clover silage prepared at an early stage of maturity represents a sustainable nutritional strategy for enhancing the MUFA and PUFA content of milk.
Simulation of flow around a thin, flexible obstruction by means of a deforming grid overlapping a fixed grid
Authors: Liu Kunlun , Radhakrishnan Hari , Barocas Victor H.
Published: June 2007

This paper presents a numerical method for simulation of coupled flows, in which the fluid interacts with a thin deformable solid, such as flows in cardiovascular valves. The proposed method employs an arbitrary Lagrangian–Eulerian (ALE) method for flow near the solid, embodied in the outflow domain in which the mesh is fixed. The method was tested by modelling a two‐dimensional channel flow with a neo‐Hookean obstacle, an idealization of the coupled flow near a cardiovascular valve. The effects of the Reynolds number and the dimensionless elastic modulus of the material on the wall shear stress, the size of the downstream reverse flows, and the velocity and pressure profiles were investigated. The deformation of the obstacle, the pressure drop across the obstacle, and the size of the top reverse flow increased as the Reynolds number increased. Conversely, increasing the elastic modulus of the obstacle decreased the deformation of
the obstacle and the size of the top reverse flows, but did not affect the pressure drop across the obstacle over the range studied. Copyright © 2007 John Wiley & Sons, Ltd.
Historical underpinnings of access to American higher education
Authors: Noftsinger Jr. John B. , Newbold Jr. Kenneth F.
Published: June 2007

This chapter explores how access became central to the missions of American colleges and universities.
A New and Efficient Synthesis of the HMG‐CoA Reductase Inhibitor Pitavastatin
Authors: Acemoglu Murat , Brodbeck Andre , Garcia Angel , Grimler Dominique , Hassel Marc , Riss Bernhard , Schreiber Robert
Published: June 2007

A new synthetic method for the preparation of pitavastatin is described. The approach circumvents various synthetic problems associated with the buildup of the 3,5‐dihydroxy‐C7 acid side chain of HMG‐CoA reductase inhibitors (statins). The use of the C6‐amide derivative 5 instead of ester derivatives in the coupling reaction with carboxaldehyde 8 (Scheme 3) prevents undesired side reactions, such as eliminations and retro‐aldol reactions. The method provides synthetic statins, such as pitavastatin, in >99% ee and exceptionally high overall yield. The enantiomerically pure starting material, (3S)‐3‐{[(tert‐butyl)dimethylsilyl]oxy}‐5‐oxo‐5‐{[(1S)‐1‐phenylethyl]amino}pentanoic acid (3c), is prepared by an improved procedure from 3‐{[(tert‐butyl)dimethylsilyl]oxy}glutaric anhydride (1) and (1S)‐1‐phenylethylamine (2c; Scheme 1).
Metal‐chelating affinity hydrogels for sustained protein release
Authors: Lin Chien‐Chi , Metters Andrew T.
Published: June 2007

Affinity hydrogels based on poly(ethylene glycol) diacrylate and a metal‐ion‐chelating ligand, glycidyl methacrylate–iminodiacetic acid, have been developed to systematically decrease protein release rates from hydrophilic tissue engineering scaffolds formed in situ. In the current work, tunable and sustained release of a model protein, hexa‐histidine tagged green fluorescence protein (hisGFP), is accomplished by judiciously increasing ligand:protein ratio or replacing low‐affinity nickel ions with high‐affinity copper ions. Agreement between theoretical predictions of a reaction‐diffusion model and experimental measurements confirm metal‐ ion‐mediated sustained protein release from these affinity hydrogels is governed by equilibrium protein–ligand binding affinity (dissociation constant, Kd) as well as protein–ligand dissociation kinetics (protein debinding rate constant, koff). The former dictates the release rate in the early period of protein release while the latter determines the long‐term sustained release effect. While metal‐ion affinity binding has been widely used for various purposes including protein purification and surface patterning, this is the first report describing its application in systematically controlling protein release from hydrophilic PEG networks suitable for cell encapsulation. By using ligands with proper binding kinetic constants (Kd and koff), localized protein delivery can be sustained over clinically relevant timescales while maintaining a favorable environment for cell encapsulation and viability. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Classification of Aurantii Fructus samples by multivariate analysis
Authors: Chuang Ching‐Ching , Wen Wu‐Che , Sheu Shuenn‐Jyi
Published: June 2007

Twenty commercial samples of Aurantii Fructus Immaturus (Poncitrus trifoliata) and 30 of Aurantii Fructus Maturus (Citrus aurantium and C. wilsonii) were collected from the Taiwan and China herbal markets. The contents of 12 constituents in these samples were determined by HPLC and were used to assess the potential relationships with their plant origins. Multivariate analysis including principal component analysis (PCA), cluster analysis (CA), and linear discriminant analysis (LDA) were used as classification procedures. Natural groupings of the samples divided into three sets successfully, 20 P. trifoliata, 15 C. aurantium, and 15 C. wilsonii, were observed by using PCA and CA. The application of LDA gave correct assignation percentages of 100.0% for all three groups.
Amphiphilic Invertible Polyesters as Reducing and Stabilizing Agents in the Formation of Metal Nanoparticles
Authors: Kohut Ananiy , Voronov Andrej , Samaryk Volodymyr , Peukert Wolfgang
Published: June 2007

Metal nanoparticles of various size and shape are prepared by the reduction of metal precursors in polymer micellar architectures (nanoreactors). The nanoreactors are developed from the amphiphilic invertible polyesters solved over a wide concentration range in solvents that strongly differ in polarity. In a non‐polar medium, the micelle core contains hydrophilic [poly(ethylene oxide)] fragments, which acts as a reducing agent of metal ions. Nanoparticle stabilization occurs because of the presence of hydrophobic (polymethylene) fragments outside of the micelle structure. The size and shape of the nanoreactors may be altered by the polyester composition and molecular weight as well as by the solvent polarity and concentration of the amphiphilic polyester.

magnified image
Prozessintegriertes Pulverbeschichten durch Radial‐Axial Ringwalzen
Authors: Moll H. , Theisen W. , Hammelmann R. , Meier H.
Published: June 2007

Pulvermetallurgisch hergestellte Bauteile, die hohen Spannungen und/oder starken abrasiven Verschleißbelastungen ausgesetzt sind, tolerieren keinerlei Restporosität. Der oftmals eingesetzte Prozess des Heiß‐Isostatischen Pressens ermöglicht zuverlässig eine Komprimierung bis zur theoretischen Dichte, ist jedoch teuer und beschränkt die herstellbare Bauteilgröße aufgrund der Dimensionen existierender HIP‐Öfen. Die Volkswagenstiftung fördert die Entwicklung eines alternativen Produktionsprozesses, durch den, auf Basis des Radial‐Axial Ringwalzens, pulvermetallurgische Verschleißschutzschichten aus Metal‐Matrix‐Composites (MMC) auf ringförmige Bauteile aufgebracht werden können. Die in diesem Prozess eingesetzten Ringrohlinge verfügen über eine, auf der Stirnseite des Ringes eingebrachte Aussparung, die durch ein Blech verschlossen wird. Der so geschaffene Kapselraum nimmt die Pulvermischung auf, aus der im Verlauf des Prozesses die Beschichtung erzeugt wird. DerWalzprozess führt zur Verdichtung des Pulvers und Anbindung der Schicht an den Grundwerkstoff. Darüber hinaus werden die Umformkräfte genutzt, um den Ringdurchmesser aufzuweiten.
Voxel based morphometry reveals specific gray matter changes in primary dystonia
Authors: Egger Karl , Mueller Joerg , Schocke Michael , Brenneis Christian , Rinnerthaler Martina , Seppi Klaus , Trieb Thomas , Wenning Gregor K. , Hallett Mark , Poewe Werner
Published: June 2007

The present study assessed patterns of brain tissue alterations in different types of primary dystonia using voxel‐based morphometry (VBM). Nine patients with primary generalized dystonia (GD), 11 patients with primary cervical dystonia (CD), and 11 patients with primary focal hand dystonia (FHD) as well as 31 age and gender‐matched controls were included. When compared with healthy controls, patients with primary dystonia (n = 31) showed gray matter volume increase bilaterally in the globus pallidus internus, nucleus accumbens, prefrontal cortex, as well as unilaterally in the left inferior parietal lobe. This is the first study using VBM in patients with different types of primary dystonia, showing a common pattern of gray matter changes. © 2007 Movement Disorder Society
Dual‐mode DC‐block semicircular‐patch bandpass filter using slot technique
Authors: Liu Haiwen , Knoechel Reinhard H. , Sun Lingling , Schuenemann Klaus F.
Published: June 2007

A simple semicircular‐patch bandpass filter (BPF) is presented in this letter. The slot between two semicircular‐patch resonators provides DC blocking and a strong coupling, while the slotted orthogonally feed lines are used to obtain the dual‐mode characteristics. Measurement demonstrates the proposed design methodology and filter. As we know, this is the first report on the microstrip dual‐mode BPF using semicircular‐patch structure. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2261–2263, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22676
Estimating the magnitude of data asymmetry in palaeozoological biogeography
Authors: Lyman R. L.
Published: June 2007

Palaeozoological data are asymmetrical because they indicate the presence of a species in the area in which its remains are recovered, but the absence of remains is not necessarily evidence for the absence of a species. It is impossible to measure the magnitude of data asymmetry with respect to biogeography, but the magnitude can be estimated. The proportion of sites in an area where a species is known to occur that have not produced remains of that species is an estimate of counter‐ubiquity. The proportion of identified faunal remains in an area where a species is known to occur that do not represent that species is another estimate of data asymmetry. Bivariate plots of the number of sites in an area that have produced remains of a taxon against the total number of faunal remains identified in the area indicate that data asymmetry can be estimated as the inverse of sample size. More sites and more identified faunal remains tend to produce more occurrences of a species, so more sites and more identified faunal remains will tend to provide a database that is not only more accurate but also less asymmetrical with respect to the geographical range of a species. Copyright © 2007 John Wiley & Sons, Ltd.
Percent absent end‐diastolic velocity in the umbilical artery waveform as a predictor of intrauterine fetal demise of the donor twin after selective laser photocoagulation of communicating vessels in twin–twin transfusion syndrome
Authors: Kontopoulos E. V. , Quintero R. A. , Chmait R. H. , Bornick P. W. , Russell Z. , Allen M. H.
Published: June 2007

Objective

Absent end‐diastolic velocity (AEDV) in the umbilical artery of the donor twin is a known risk factor for intrauterine fetal demise (IUFD) of this fetus after selective laser photocoagulation of communicating vessels (SLPCV) for twin–twin transfusion syndrome (TTTS). The aim of this study was to assess the proportion of time, expressed as a percentage, of the cardiac cycle spent in AEDV (%AEDV) as a predictor of IUFD of the donor.

Methods

All patients referred for possible SLPCV underwent complete preoperative staging evaluation including Doppler assessment of the umbilical artery. %AEDV was calculated retrospectively as 100 × (time of the cycle spent in AEDV divided by duration of total cardiac cycle). Patients without AEDV were considered to have a %AEDV of 0. Follow‐up Doppler studies were performed 16–24 h after SLPCV. IUFD of the donor was recorded if the donor twin died any time prior to delivery.

Results

Of 401 patients undergoing SLPCV, 127 had AEDV. Preoperative AEDV of the donor twin was associated with an increased risk of IUFD of the donor (40.9% vs. 14.2%, P < 0.0001). %AEDV was measured in 72/127 (56.7%) donors with AEDV for whom digital images were available. Within these 72 patients, the mean %AEDV was significantly higher in patients with IUFD of the donor (36.5% vs. 29.6%, P = 0.01). IUFD of the donor was similar in patients with AEDV, regardless of whether %AEDV was measured (36% vs. 47%, P = 0.2). A %AEDV > 30 was associated with a 4.3‐fold increase in the risk of IUFD of the donor (95% CI, 1.4–12.7), a sensitivity of 77% and a negative predictive value of 81.3%. Logistic regression showed that %AEDV, but not number of anastomoses, placental location, presence of artery‐to‐artery anastomoses or the presence or absence of EDV was associated significantly with IUFD of the donor.

Conclusion

%AEDV is a novel Doppler parameter in the assessment of patients with TTTS. %AEDV, rather than AEDV alone, is a significant risk factor for IUFD of the donor twin and %AEDV > 30 is associated with an increased risk of IUFD of the donor in TTTS patients treated with SLPCV. Assessment of %AEDV should be considered part of the preoperative evaluation of TTTS patients. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Carbamoylphosphate serves as the source of CN−, but not of the intrinsic CO in the active site of the regulatory [NiFe]‐hydrogenase from Ralstonia eutropha
Authors: Lenz Oliver , Zebger Ingo , Hamann Josta , Hildebrandt Peter , Friedrich Bärbel
Published: June 2007

Within the catalytic centre of [NiFe]‐hydrogenases one carbonyl and two cyanide ligands are covalently attached to the iron. To identify the metabolic origins of these ligands, the regulatory [NiFe] hydrogenase in conjunction with the indigenous Hyp maturation proteins of Ralstonia eutropha H16 were heterologously overproduced in E. coli grown in the presence of l‐[ureido‐13C] citrulline and NaH13CO3. Infrared spectroscopy of purified hydrogenase provided direct evidence that only the cyanide ligands, but not the CO ligand, originate from CO2 and carbamoylphosphate. Incorporation of label from 13CO exclusively into the carbonyl ligand indicates that free CO is a possible precursor in carbonyl ligand biosynthesis.
Factors influencing parameters of laser ion sources
Authors: Láska L. , Badziak J. , Boody F.P. , Gammino S. , Jungwirth K. , Krása J. , Krouský E. , Parys P. , Pfeifer M. , Rohlena K. , Ryć L. , Skála J. , Torrisi L. , Ullschmied J. , Wolowski J.
Published: June 2007

Various applications demand various kinds of ions. Charge state, energy and the amount of laser produced ions depend, primary, on the wavelength, the energy, the pulse duration, and the focusing ability of the laser used. Angle of the target irradiation, angle of the ion extraction (recording), and mainly the focus setting may significantly influence especially the portion of ions with the highest charge states. The participation of non-linear processes on the generation of ions with extremely high parameters is demonstrated. The observed effects support the idea of a longitudinal structure of the self-focused laser beam with a space period of ∼200 µm.
Laser electron accelerator in plasma with adiabatically attenuating density
Authors: SHI Y-J.
Published: June 2007

In this paper, we present a novel kind of electron acceleration mechanism when the trapped electrons are in a wake of plasma with adiabatically attenuating density. Accompanied with the increase of phase velocity βp of the wake owing to the plasma density attenuating adiabatically, the trapped electrons synchronized with the wake will get an additional acceleration besides the synchrotron oscillating acceleration just like in an accelerating elevator. The additional energy gain of the trapped electrons is determined by the value of the relativistic factor γpf = ω/ωp(zf) at the exit zf of the plasma wake. Moreover, the acceleration length is not limited by the dephasing deterministically any more, instead, it is mainly determined by the survivability of the wake. In other words, it is dependent upon the wake instability and its involving energy from driving source.
High energy density physics problems related to liquid jet lithium target for Super-FRS fast extraction scheme
Authors: Tahir N.A. , Kim V. , Lomonosov I.V. , Grigoriev D.A. , Piriz A.R. , Weick H. , Geissel H. , Hoffmann D.H.H.
Published: June 2007

The new international facility for antiproton and ion research (FAIR), at Darmstadt, Germany, will accelerate beams of all stable isotopes from protons up to uranium with unprecedented intensities (of the order of 1012 ions per spill). Planned future experiments include production of exotic nuclei by fragmentation/fission of projectile ions of different species with energies up to 1.5 GeV/u at the proposed super conducting fragment separator, Super-FRS. In such experiments, the production target must survive multiple irradiations over an extended period of time, which in case of such beam intensities is highly questionable. Previous work showed that with full intensity of the uranium beam, a solid graphite target will be destroyed after being irradiated once, unless the beam focal spot is made very large that will result in extremely poor transmission and resolution of the secondary isotopes. An alternative to a solid target could be a windowless liquid jet target. We have carried out three-dimensional numerical simulations to study the problem of target heating and propagation of pressure in a liquid Li target. These first calculations have shown that a liquid lithium target may survive the full uranium beam intensity for a reasonable size focal spot.
Electron acceleration by high current-density relativistic electron bunch in plasmas
Authors: ZHOU C.T. , YU M.Y. , HE X.T.
Published: June 2007

Electron acceleration by a short high-current relativistic electron bunch (EB) in plasmas at three characteristic densities is studied by particle-in-cell simulation. It is found that if the EB is appropriately matched to the background plasma, the blowout space-charge field of the EB can accelerate the trailing bunch electrons at very high energy gain rate. This high energy gain, as well as the large-amplitude wakefield, the turbulent small-scale electron plasma waves, and the formation of large current peaks, are studied. The evolution of the EB, its blowout field, and other related parameters are shown to be self-similar.
Cross-protective and cross-reactive immune responses to recombinant vaccinia viruses expressing full-length lyssavirus glycoprotein genes
Authors: WEYER J. , KUZMIN I. V. , RUPPRECHT C. E. , NEL L. H.
Published: June 2007

Lyssaviruses cause acute, progressive encephalitis in mammals. Current rabies vaccines offer protection against the lyssaviruses, with the notable exceptions of Mokola virus (MOKV), Lagos bat virus (LBV) and West Caucasian bat virus (WCBV). Here we describe the cross-protective and cross-reactive immune responses induced by experimental recombinant vaccinia viruses encoding the glycoprotein genes of rabies virus (RABV), MOKV and WCBV, either singly or in dual combinations. Constructs expressing a single glycoprotein gene protected mice against lethal intracranial challenge with homologous virus. Similarly, recombinants expressing glycoprotein genes from two different lyssaviruses offered mice protection against both homologous viruses. VNAb induced by vaccines that included a MOKV glycoprotein gene cross-neutralized LBV, but not WCBV. We concluded that a single recombinant poxvirus-vectored vaccine including MOKV and RABV glycoprotein genes, should be a major addition to available rabies biologics and should offer broad protection against all of the lyssaviruses, except WCBV.
Pure water vapor continuum measurements between 3100 and 4400 cm−1: Evidence for water dimer absorption in near atmospheric conditions
Authors: Paynter D. J. , Ptashnik I. V. , Shine K. P. , Smith K. M.
Published: June 2007

Despite the potentially important role that water dimers may play in the Earth's energy balance, there is still a lack of firm evidence for absorption of radiation by dimers in near‐atmospheric conditions. We present results of the first high‐resolution laboratory measurements of the water vapor continuum absorption within the 3100–4400 cm−1 spectral region at a range of near‐room temperatures. The analysis indicates a large contribution of dimer absorption to the water vapor continuum, significantly in excess of that predicted by other modern representations of the continuum. The temperature dependence agrees well with that expected for dimers.
Methane release below a tropical hydroelectric dam
Authors: Kemenes Alexandre , Forsberg Bruce Rider , Melack John Michael
Published: June 2007

Tropical reservoirs upstream from hydroelectric dams are known to release significant amounts of methane to the atmosphere. Here we demonstrate that methane emissions downstream from hydroelectric dams can also be large. Emissions of CH4 downstream of Balbina reservoir in the central Amazon basin (Brazil) were calculated from regular measurements of degassing in the outflow of the turbines and downstream diffusive losses. Annual emissions from the reservoir surface and downstream from the dam were 34 and 39 Gg C, respectively. The downstream emission alone represented the equivalent of 3% of all methane released from central Amazon floodplain.
Detection of silica‐mediated dissolution of magnetic grains in sediments using FORC diagrams
Authors: Wetter Laura , Verosub Ken , Russell James
Published: June 2007

Recently silica‐mediated dissolution has been recognized as a potentially important factor influencing magnetic studies of marine and lacustrine sediments. Although direct evidence for the dissolution of magnetic particles in silica‐rich environments is lacking, the process is expected to produce changes in the magnetic grain‐size distribution, a hypothesis that is tested in this study on sediments from Lake Tanganyika, East Africa, using First Order Reversal Curves (FORCs). Results from different magnetic intensity zones within the studied samples clearly show changes in the grain‐size distribution of magnetic minerals. In particular, zones with high biogenic silica content (BSi) correlated with depletion in fine‐grained magnetic material, whereas zones with lower BSi showed no depletion. These results are consistent with the idea that silica‐mediated dissolution results in the preferential removal of fine‐grained magnetic material, and indicate that FORC diagrams are effective in characterizing silica‐mediated dissolution in sediments.
Ultraviolet emission blueshift of ZnO related to Zn
Authors: Lee Ming-Kwei , Tu Hwai-Fu
Published: June 2007

The optical properties of electrodeposited Zn-ZnO structures annealed at different temperature in oxygen ambient are studied. Zn and ZnO coexist in all samples measured by x-ray diffraction, but only ZnO is observed for a sample annealed at 800 °C. From photoluminescence analyses, green and orange-red emissions are observed from an as-prepared sample. The spectrum is almost the same for the sample annealed at 300 °C. It shows a strong ultraviolet (UV) emission at the wavelength of 374 nm for the annealing temperature of 500 °C; the UV emission redshifts to 384 nm for the annealing temperature of 800 °C. The existence of metallic Zn crystals in ZnO plays a significant role in the emission characteristics.
Effect of charged and excited states on the decomposition of 1,1-diamino-2,2-dinitroethylene molecules
Authors: Kimmel Anna V. , Sushko Peter V. , Shluger Alexander L. , Kuklja Maija M.
Published: June 2007

The authors have calculated the electronic structure of individual 1,1-diamino-2,2-dinitroethylene molecules (FOX-7) in the gas phase by means of density functional theory with the hybrid B3LYP functional and 6-31+G(d,p) basis set and considered their dissociation pathways. Positively and negatively charged states as well as the lowest excited states of the molecule were simulated. They found that charging and excitation can not only reduce the activation barriers for decomposition reactions but also change the dominating chemistry from endo- to exothermic type. In particular, they found that there are two competing primary initiation mechanisms of FOX-7 decomposition: C–NO2 bond fission and C–NO2 to CONO isomerization. Electronic excitation or charging of FOX-7 disfavors CONO formation and, thus, terminates this channel of decomposition. However, if CONO is formed from the neutral FOX-7 molecule, charge trapping and/or excitation results in spontaneous splitting of an NO group accompanied by the energy release. Intramolecular hydrogen transfer is found to be a rare event in FOX-7 unless free electrons are available in the vicinity of the molecule, in which case HONO formation is a feasible exothermic reaction with a relatively low energy barrier. The effect of charged and excited states on other possible reactions is also studied. Implications of the obtained results to FOX-7 decomposition in condensed state are discussed.