bluuebunny/crossref_metadata_2025 huggingface dataset:
Mesoscale model of polymer melt structure: Self-consistent mapping of molecular correlations to coarse-grained potentials
Authors: Ashbaugh Henry S. , Patel Harshit A. , Kumar Sanat K. , Garde Shekhar
Published: March 2005

Development and application of coarse-graining methods to condensed phases of macromolecules is an active area of research. Multiscale modeling of polymeric systems using coarse-graining methods presents unique challenges. Here we apply a coarse-graining method that self-consistently maps structural correlations from detailed molecular dynamics (MD) simulations of alkane oligomers onto coarse-grained potentials using a combination of MD and inverse Monte Carlo methods. Once derived, the coarse-grained potentials allow computationally efficient sampling of ensemble of conformations of significantly longer polyethylene chains. Conformational properties derived from coarse-grained simulations are in excellent agreement with experiments. The level of coarse graining provides a control over the balance of computational efficiency and retention of chemical identity of the underlying polymeric system. Challenges to extension and application of this and similar structure-based coarse-graining methods to model dynamics and phase behavior in polymeric systems are briefly discussed.
Surface effects in magnetic nanoparticles measured by means of a magneto-optical method
Authors: Rosa G. , Guerrero H. , Levy D. , Álvarez-Herrero A. , del Real R. P.
Published: March 2005

Faraday rotation measurements have been made in samples composed of γ-Fe2O3 nanoparticles dispersed in a SiO2 matrix. All the samples show the same Fe∕Si molar ratio but different diameters of the magnetic nanoparticles. A magneto-optical method to measure the particle size using the Faraday effect is presented. The increase of Faraday rotation with the mean diameter of the γ-Fe2O3 particles can be associated with surface effects. The thickness value of their external layer with disordered spins has been obtained using a simple model and its high value suggests the large influence of the matrix on the magnetic properties of the composite.
Microstructural and high-frequency magnetic characteristics of W-type barium ferrites doped with V2O5
Authors: Wu Y. P. , Ong C. K. , Li Z. W. , Chen Linfeng , Lin G. Q. , Wang S. J.
Published: March 2005

The microstructure, static, and dynamic magnetic properties have been investigated for BaCoZnFe16O27 doped with small amounts of V2O5 from 0 to 1.5wt%. The results show that the doping of V2O5 can significantly improve the dynamic properties of W-type barium ferrites at microwave frequency. As compared to the undoped sample, the permeabilities μ0′ and μmax″ increase by about 42% and 67%, respectively, for the sample doped with 1.0wt% of V2O5. Due to the V2O5 doping, perfect hexagonal-plate grains are formed, leading to the decrease in the natural resonance frequency, due to the large demagnetizing effect. The predicted reflection loss shows that the maximum relative bandwidth Wmax=fup∕flow reaches 3.9 for attenuation of more than 10dB in the sample doped with 1.0wt% of V2O5. This is a good candidate for electromagnetic materials with low reflectivity and broadband at microwave frequency.
Electric-field effects of dielectric and optical properties in Pb(Mg1∕3Nb2∕3)0.65Ti0.35O3 crystal
Authors: Tu Chi-Shun , Wang F.-T. , Chien R. R. , Schmidt V. Hugo , Tuthill George F.
Published: March 2005

Dielectric properties and domain structure have been measured as functions of temperature in a (001)-oriented Pb(Mg1∕3Nb2∕3)0.65Ti0.35O3 (PMNT35%) single crystal with and without a prior dc electric (E)-field poling. Without E-field poling, the dielectric loss exhibits a frequency-dependent maximum in the region of 120–180K, which can be described by a Vogel–Fulcher equation and fractal cluster model which implies structural irregularities within domains. With a prior poling a long-range monoclinic (tetragonal)→tetragonal (monoclinic) transition takes place near 212K upon heating. “Monoclinic (tetragonal)” represents that dominant monoclinic phase domains coexist with a small fraction of tetragonal phase domains. Optical transmission and birefringence were significantly enhanced by a prior E-field poling. The Cauchy equations for ordinary no and extraordinary ne refractive indices were determined between 0.45 and 1.4μm. However, the phase-matching criterion for second-harmonic generation was not found.
Atomistic simulation of the homogeneous nucleation and of the growth of N2 crystallites
Authors: Leyssale Jean-Marc , Delhommelle Jerome , Millot Claude
Published: March 2005

We report on a computer simulation study of the early stages of the crystallization of molecular nitrogen. First, we study how homogeneous nucleation takes place in supercooled liquid N2 for a moderate degree of supercooling. Using the umbrella sampling technique, we determine the free energy barrier of formation for a critical nucleus of N2. We show that, in accord with Ostwald’s rule of stages, the structure of the critical nucleus is predominantly that of a metastable polymorph (α-N2 for the state point investigated). We then monitor the evolution of several critical nuclei through a series of unbiased molecular dynamics trajectories. The growth of N2 crystallites is accompanied by a structural evolution toward the stable polymorph β-N2. The microscopic mechanism underlying this evolution qualitatively differs from that reported previously. We do not observe any dissolution or reorganization of the α-like core of the nucleus. On the contrary, we show that α-like and β-like blocks coexist in postcritical nuclei. We relate the structural evolution to a greater adsorption rate of β-like molecules on the surface and show that this transition actually starts well within the precritical regime. We also carefully investigate the effect of the system size on the height of the free energy barrier of nucleation and on the structure and size of the critical nucleus.
Device simulation for GaAs∕AlGaAs superlattice infrared photodetector with a single current blocking layer
Authors: Clames Jan-Yves , Lin Shih-Yen , Chi Jim-Yong , Chou Shu-Ting , Wu Meng-Chyi
Published: March 2005

The influence of operation voltages and doping densities on superlattice infrared photodetectors (SLIPs) with a single current blocking layer has been investigated. Higher responsivity and the redshift of peak-responsivity wavelength with increasing applied voltage are observed for SLIP with higher quantum-well doping. The phenomenon is attributed to the increase in tunneling probability for low-energy photoelectrons with increased applied voltage. Taking into consideration the shift in Fermi level at different doping densities in the quantum well and the electron-tunneling probability for the front blocking layer, the spectral responses under different applied voltages can be derived by the summation of dipole transitions for each energy states in the minibands. It is shown that the measurement data and the simulation results are identical for devices applied under different voltages and with different quantum-well doping densities.
Polarization fatigue in PbZr0.45Ti0.55O3-based capacitors studied from high resolution synchrotron x-ray diffraction
Authors: Menou N. , Muller Ch. , Baturin I. S. , Shur V. Ya. , Hodeau J.-L.
Published: March 2005

High resolution synchrotron x-ray diffraction experiments were performed on (111)-oriented PbZr0.45Ti0.55O3-based capacitors with a composition in the morphotropic region. Diffraction analyzes were done after bipolar pulses were applied and removed, representing several places in the cyclic switching. Microstructural changes were evidenced from relative diffracted intensities variations of several Bragg reflections and a correlation with the evolution of the ferroelectric responses has been established. First, a peculiar microstructural evolution was observed during the first 3×104 switching cycles and was attributed to the so-called “wake-up” effect. On the other hand, the onset of the fatigue phenomenon was accompanied by significant variations on integrated diffraction intensities. Several mechanisms are proposed and discussed to explain such variations. Finally, the ferroelectric responses were analyzed after x-ray diffraction experiments and compared with those measured before exposure. A detailed analysis has shown that both domain configuration and switching process are strongly influenced by x-ray irradiation. It can be considered that x rays act as a “revealer” of the domain structure created during the preceding electrical treatment.
Pseudomorphic strain effect on the charge-orbital ordering pattern in Pr0.5Sr0.5MnO3 epitaxial thin films
Authors: Ogimoto Yasushi , Takubo Naoko , Nakamura Masao , Tamaru Hiroharu , Izumi Makoto , Miyano Kenjiro
Published: March 2005

We accomplished coherent epitaxial growth of a Pr0.5Sr0.5MnO3 thin film on (LaAlO3)0.3–(SrAl0.5Ta0.5O3)0.7 (110) substrate, which demonstrates a robust charge-orbital ordering (COO) phase transition. In addition to the isotropic transport properties, a drastic recovery of high-resistivity state (>20Ωcm) from a field-cooled metallic state (∼0.5mΩcm) was observed at 5K with a release of a magnetic field. These results indicate a possible modification of COO pattern into CE-type COO state [d(3x2−r2∕3y2−r2)] in the film from A-type stripe COO state [d(x2−y2)] observed in bulk samples by a substrate-induced strain.
Site-controlled photoluminescence at telecommunication wavelength from InAs∕InP quantum dots
Authors: Song H. Z. , Usuki T. , Hirose S. , Takemoto K. , Nakata Y. , Yokoyama N. , Sakuma Y.
Published: March 2005

We fabricated ordered InAs∕InP quantum-dot (QD) arrays using atomic-force-microscopic oxidation, wet etching, and regrowth by metalorganic chemical vapor deposition. The QDs exhibit single-dot photoluminescence peaking at wavelengths ranging from 1.22 to 1.45μm, mostly matching the telecommunication band of optical fibers. The site dependence of single peaks indicates the site controllability of single-dot light emitters, which might be useful in quantum information processing.
Coding for spatial goals in the prelimbic/infralimbic area of the rat frontal cortex
Authors: Hok V. , Save E. , Lenck-Santini P. P. , Poucet B.
Published: March 2005

Finding one's way in space requires a distributed neural network to support accurate spatial navigation. In the rat, this network likely includes the hippocampus and its place cells. Although such cells allow the organism to locate itself in the environment, an additional mechanism is required to specify the animal's goal. Here, we show that firing activity of neurons in medial prefrontal cortex (mPFC) reflects the motivational salience of places. We recorded mPFC neurons from rats performing a place navigation task, and found that a substantial proportion of cells in the prelimbic/infralimbic area had place fields. A much smaller proportion of cells with such properties was found in the dorsal anterior cingulate area. Furthermore, the distribution of place fields in prelimbic/infralimbic cells was not homogeneous: goal locations were overrepresented. Because such locations were spatially dissociated from rewards, we suggest that mPFC neurons might be responsible for encoding the rat's goals, a process necessary for path planning.
Between ‘Paper’ and ‘Real Tigers’: Mao's View of Nuclear Weapons
Authors: Shu Guang Zhang
Published: March 2005

Mao Zedong originally saw a new China's struggle for security in terms of conventional warfare and in 1946 satirized the atomic bomb as a ’paper tiger’. Mao found it difficult to understand why the imperialists would venture to use nuclear weapons in a war if they wanted to dominate other nations, because a massively destructive weapon would not serve the purpose of acquiring political control, but would instead destroy that which was to be controlled. However, he gradually changed his position, as he understood the deterrent value of the bomb. Frequent US nuclear threats against China, Soviet pressures, and pressures from other Chinese leaders who kept pushing Mao to pay more attention to nuclear‐weapon programmes are the important factors that contributed to his ’nuclear revolution’. Consequently, his thinking on the atomic bomb came to dominate China's defence policy and brought about the policy changes that turned China into a major nuclear power.
TEACHING COSMOPOLITAN RIGHT
Authors: Reich Rob
Published: March 2005

The essays in Part III of the book, on liberal constraints and traditionalist education, argue for a more regulatory conception of liberal education and emphasize the need for some controls over cultural and religious educational authority. Rob Reich’s essay, on multicultural accommodations in education, proposes that the liberal state needs to rethink its commitment to cultural groups whose educational agendas advance the integrity of the group over and against the freedom and equality of its members, and that thus educate in ways that place strict limits on the autonomy and critical thinking skills of their members. He aims to examine two prominent defenses of multiculturalism, showing how each pays insufficient attention to the tension between cultural groups: Avishai Margalit and Moshe Halbertal argue that, because individuals have a ‘right to culture’, the state must grant groups a status that may flout the rights of some individuals, conditioned on the ability of those individuals to exit; Will Kymlicka, in a far more sophisticated version of multiculturalism, defends cultural rights, and accommodations, but only for those cultural groups that are themselves internally liberal (except in rare circumstances) and that take seriously the value of personal autonomy. Reich contends that, while the freedom to exit from a group is important, the group rights supported by Margalit and Halbertal may serve to disable or severely impoverish the ability of children to exit from groups; further, he contends that, while personal autonomy is important, Kymlicka’s conception of autonomy is unsatisfactory and, moreover, his defense of rights to separate schooling for national minorities and to educational exemptions for some polyethnic groups leaves him open to the same critique about exit that Reich levies against Margalit and Halbertal. Along the way, Reich comments on the odd fixation of multiculturalists on rights of exit.
“MISTRESSES OF THEIR OWN DESTINY”: GROUP RIGHTS, GENDER, AND REALISTIC RIGHTS OF EXIT
Authors: Moller Okin Susan
Published: March 2005

The essays in Part III of the book, on liberal constraints and traditionalist education, argue for a more regulatory conception of liberal education and emphasize the need for some controls over cultural and religious educational authority. Susan Okin, in her essay on group rights, gender, and realistic rights of exit, is mostly concerned, not with the oppression of traditional groups by the liberal state, but with the oppression of individuals, and especially of girls and women, by the traditional community. She is critical of those liberal theorists who argue that a right of exit is sufficient to qualify a cultural or religious group for special recognition in liberal societies, and to counter these views, she notes that the unequal treatment of girls and women can mean that even though they may have a formal right to exit a group, their actual opportunities for doing so are far less adequate than those of their male counterparts. She holds, then, that the right of exit is not sufficient and that the liberal state should have a higher requirement, namely, that girls and women should be treated fairly within the group and thus should be able to take advantage of any formal right of exit. The chapter is arranged in three sections: Section 12.1, Gender and Other Forms of Inequality in Group Rights Theories, shows, by looking at three examples of liberal defenders (as exemplified by Joseph Raz, William Galston, and Chandran Kukathas) of group rights, that they tend not to take gender inequality seriously when considering group rights and limitations; Section 12.2, Cultural Factors Affecting Women’s Realistic Rights of Exit, specifies and discusses a number of reasons that contribute to women being significantly less able than men, in many cultural contexts, to chart their own courses of life outside their community of origin; and Section 12.3. Rights of Exit and Realistic Rights of Exit for Women, concludes that the theories examined contain several problematic elements concerning rights of exit for women.
Chapter 4 DOCUMENTARY
Authors: Currie Gregory
Published: March 2005

Defends the idea that documentary is a distinctive and important cinematic category, though an essentially vague one. This notion depends on that of a trace. A documentary must involve traces of its subject, and not merely testimony of it. Defines an ideal documentary as one where there is a certain kind of coherence between the narrative and the trace‐content of the work. Argues that the notion of an ideal documentary explains much in our attitude towards, and practice concerning those things we commonly label documentaries.
Chapter 10 PRETENCE AND PRETENDING
Authors: Currie Gregory
Published: March 2005

Assesses the claim that metarepresentation — the mental representation of a mental representation — is a key notion in understanding the nature and development of our capacity to engage in pretence. Argues that the metarepresentational programme is unhelpful in explaining how pretence operates and, in particular, how agents distinguish pretence from reality. Sketches an alternative approach to the relations between pretending and believing.
PRETENCE AND RATIONALITY: THE CASE OF NON‐HUMAN ANIMALS
Authors: Currie Gregory
Published: March 2005

Argues that pretence is one clear indication of rationality. Makes a suggestion about the kind of evidence of pretence in animals we should be looking for. This suggestion makes claims about pretence hard to justify by comparison with, say, claims about imitation; Appeals to Morgan's canon in defence of this stance. Suggests that we can learn something about pretence by connecting it with the phenomenon of seeing‐in. Finally, offers a speculation on the evolutionary history of the capacity that underlies pretence.
Bayesian Epistemology
Authors: Bovens Luc , Hartmann Stephan
Published: March 2005

Probabilistic models have much to offer to epistemology and philosophy of science. Arguably, the coherence theory of justification claims that the more coherent a set of propositions is, the more confident one ought to be in its content, ceteris paribus. An impossibility result shows that there cannot exist a coherence ordering. A coherence quasi-ordering can be constructed that respects this claim and is relevant to scientific-theory choice. Bayesian-Network models of the reliability of information sources are made applicable to Condorcet-style jury voting, Tversky and Kahneman’s Linda puzzle, the variety-of-evidence thesis, the Duhem–Quine thesis, and the informational value of testimony.
The effect of physical training on bone mineral density in women with endometriosis treated with GnRH analogs: a pilot study
Authors: Bergström Ingrid , Freyschuss Bo , Jacobsson Hans , Landgren Britt‐Marie
Published: March 2005

Background.  The effect of physical training on bone mineral density (BMD) in women with endometriosis treated with gonadotropin‐releasing hormone (GnRH) analogs was studied.

Methods.  Nineteen Caucasian premenopausal women aged 23–38 years were included in the study. The subjects were all treated with 21.6 mg goserelin during 6 months. The patients were randomized to physical training n = 8 or to a control group n = 11. The total period of training was 12 months, whereas GnRH treatment was terminated after 6 months. BMD was measured in the femoral neck area and the lumbar spine using dual X‐ray absorptiometry (DEXA). This was performed just before treatment, after 6 months and after 12 months. Six women fulfilled the training during 12 months of observation. In the control group 10 women were followed up for 12 months.

Results.  After 6 months the women in the physical training group were 2.1% below baseline. Six months later these women had gained BMD in the femoral neck and were 0.6% below baseline. Those in the control group lost 2.8% after 6 months and were 3.6% below baseline after 12 months. The difference in loss of BMD after 12 months between the groups was significant 0.029. In the spine there was no significant difference between the two groups.

Conclusions.  Physical training in women with endometriosis was found to rebuild bone after treatment with GnRH analogs when compared to a control group. This effect could be demonstrated 6 months after cessation of GnRH treatment.
Increased hyaluronan and CD44 expressions in intravenous leiomyomatosis
Authors: Chen Mei‐Jou , Peng Yeh , Yang Yu‐Shih , Huang Su‐Cheng , Chow Song‐Nan , Torng Pao‐Ling
Published: March 2005

Background.  To determine the influence of hyaluronan and its receptor CD44 in the angiogenesis and invasiveness of intravenous leiomyomatosis (IVL).

Methods.  Paraffin‐embedded sections from four IVL cases and 10 uterine leiomyoma cases were immunohistochemically stained for CD34, CD44, basic fibroblast growth factor (bFGF), vascular endothelial growth factor, and platelet‐derived growth factor and assayed for microvessel densities. Hyaluronan was immunostained by biotinylated hyaluronan‐binding peptide and the results were clinically correlated.

Results.  CD34 labeling showed significantly increased microvessel counts in IVL (156.6 ± 3.7), when compared to uterine leiomyomas (61.3 ± 27.3; P < 0.001). Hyaluronan and its receptor CD44 were prominently expressed in IVL when compared to leiomyomas and associated with an elevation in bFGF expression.

Conclusions.  IVL is a highly vascular neoplasm with elevated microvessel counts. The increase of hyaluronan and CD44 expression in IVL suggests that it is highly angiogenic and has an invasive potential. Elevation of hyaluronan may play a possible role in the pathogenesis of IVL.
EPR‐Characterization of Carbon Inclusions in Boron Carbide
Authors: Kakazey Mykola , Vlasova Maryna , Gonzalez‐Rodriguez Jose Gonzalo , Dominguez‐Patiño Martha , Leder Ron
Published: March 2005

In boron carbide, the dependence of EPR line width (ΔB) with g= 2.0028 on the contents of free carbon, cC, is used to determine the surface‐to‐volume ratio (S/V) of free carbon inclusions. Consecutive reduction of cC was conducted by a method of low‐vacuum oxidation at a range of temperatures. The amount of a free carbon (a graphite phase) in samples was measured by X‐ray. Analysis of changes in ΔB (cC) has shown that free carbon inclusions at the surface layer of polycrystalline boron carbide particles has S/V two times smaller than that of free carbon inclusions in the interior of polycrystalline boron carbide.
Sintering in Nitrogen Atmosphere of Iron‐Rich Glass‐Ceramics
Authors: Karamanov Alexander , Taglieri Giuliana , Pelino Mario
Published: March 2005

The sintering and the crystallization of two iron‐rich glass compositions (45–75‐μm powder fractions) were studied in air and nitrogen atmospheres. The phase formation was evaluated by differential thermal analysis, while the densification, by dilatometry; the crystalline phases were identified by X‐ray diffraction and the structure observed by scanning electron microscopy. It was highlighted that, due to the absence of Fe2+ oxidation and lower viscosity of the parent and residual glasses, the sintering in nitrogen atmospheres occurs at 100°–200°C lower temperature. In the same time the higher amount of crystal phase, formed during sinter–crystallization in inert atmosphere, improves the mechanical properties. A value of 120 MPa for the bending strength was obtained after 1‐h sintering at 960°C in N2.
Negative Thermal Expansion in (HfMg)(WO4)3
Authors: Suzuki Tomoko , Omote Atsushi
Published: March 2005

A single‐phase material (HfMg)(WO4)3 with an orthorhombic structure, A2 (WO4)3‐type tungstate, has been successfully prepared for the first time by the calcination of HfO2, MgO, and WO3, substituting Hf4+ and Mg2+ for A3+ cations in A2(WO4)3. The new material shows a negative thermal expansion coefficient of approximately −2 ppm/°C from room temperature to 800°C. The mechanism of negative thermal expansion is assumed to be the same as that of Sc2(WO4)3.
Synthesis and Stability of Nanocrystalline Lead Stannate
Authors: Xing Xianran , Chen Jun , Wei Guozhu , Deng Jinxia , Liu Guirong
Published: March 2005

Nano‐crystalline PbSnO3 was synthesized by a sol–gel route. It was an anion‐deficient pyrochlore (a=b=c= 1.0677 nm) with space group Fd3m. TEM images confirmed the nano‐size of particles as ∼10 nm, aggregated into larger clusters up to 1 μm. DSC‐TGA investigation revealed that the PbSnO3 was unstable >800°C with 2.95% weight loss. The products of the reactions, Pb2SnO4 and SnO2, were identified by in situ high‐temperature XRD. The complex decomposition reactions were deduced as (2 +x)PbSnO3= Pb2SnO4+ (1 +x)SnO2+xPbO (x= 0.104). The lattice parameters of PbSnO3 were determined by high‐temperature XRD. The cell volume of PbSnO3 increased with increasing temperatures. The average volumetric thermal expansion of PbSnO3 was calculated as (β= 3.35 × 10−5/°C).
Fabrication of Textured Si3N4 Ceramics by Slip Casting in a High Magnetic Field
Authors: Li Shuqin , Sassa Kensuke , Asai Shigeo
Published: March 2005

Developing the texture of ceramics is one of the effective ways for improving properties. Although the magnetic susceptibility of nonmagnetic materials is very small, there is a possibility to control the crystal orientation using a high magnetic field due to a magnetic anisotropy. In this study, Si3N4 ceramics were manufactured by a slip‐casting process under high magnetic field and pressureless sintering. The texture of Si3N4 ceramics was studied using X‐ray diffraction and scanning electron micrographs of polished and plasma‐etched specimens. It has been found that most of the a,b‐axes texture of β‐Si3N4 grains aligned to the magnetic field direction.
Mechanical Properties of Monoclinic Zirconia
Authors: Eichler Jens , Eisele Ulrich , Rödel Jürgen
Published: March 2005

Fracture toughness and fracture strength data are presented for the first time for monoclinic zirconia. An undoped nanocrystalline zirconia powder was sintered at 1100°C and yielded a theoretical density of more than 90% with a grain size of about 150 nm. The surface crack in flexure (SCF) technique was deemed most suitable for nanocrystalline materials. Measurements of Young's modulus and the determination of the fracture origin are also provided.
How to get published: seven easy steps
Authors: Albarran John W , Scholes Julie
Published: March 2005

As a professional group, nurses, whether as academics or practitioners, are increasingly expected to contribute to the development of quality nursing care and service provision by disseminating the findings of research, sharing innovations in clinical practice or examples of best practice. Yet, many individuals find it difficult to write informatively about their practice or to translate the outputs of academic studies into accessible publications. However, in most instances, a lack of confidence remains a key obstacle as is the lack of familiarity with processes required in preparing a paper for publication.

The aim of this paper is to discuss a series of progressive steps that must be followed when preparing a paper for publication in a peer‐reviewed journal.The main body of the paper provides a detailed analysis on the importance of deciding what to write about, selecting a suitable journal, organizing the content and structure of a paper and using appropriate language to make the article more accessible to the audience. The discussion also explores the concepts of authorship order, peer‐review process and how to respond to written reviewer's comments once the paper has been returned by the publishers. The paper concludes by stressing that success requires undertaking the necessary preparatory work, time, commitment and enthusiasm.
Subcutaneous tissue oxygen tension after coronary revascularisation with and without cardiopulmonary bypass
Authors: Cody C. , Buggy D. J. , Marsh B. , Moriarity D. C.
Published: March 2005

Directly measured subcutaneous tissue oxygen tension reflects the adequacy of regional tissue oxygenation and influences wound infection and healing. We tested the hypothesis that off‐pump coronary artery bypass would increase subcutaneous tissue oxygen tension by minimizing cardiopulmonary bypass‐induced systemic inflammation. Ten consecutive patients scheduled for off‐pump coronary artery bypass were compared with 10 undergoing conventional cardiopulmonary bypass. All patients had a tissue oxygen sensor implanted longitudinally into the subcutaneous tissue of the leg in the saphenous vein harvest wound. Data were collected from closure of the saphenous vein wound for 20 h postoperatively. Although more off‐pump patients had only one coronary artery grafted, postoperative subcutaneous tissue oxygen tension was significantly higher in off‐pump patients throughout the 20‐h study. Absolute mean (SD) differences ranged from 2.3 kPa in the first 2 h [14.4 (2.3) vs. 12.1 (2.4) kPa in off‐pump and cardiopulmonary bypass, respectively, p = 0.04] to 4.6 kPa at 8–10 h [14.0 (3.5) vs. 9.3 (2.7) kPa, p = 0.007]. In contrast, there were no significant differences in arterial oxygen tension values over this period. Mean arterial pressure and haemoglobin were transiently higher in off‐pump patients at 8 h only. We conclude that postoperative subcutaneous tissue oxygen tension was higher for 20 h after off‐pump compared with conventional cardiopulmonary bypass.
A defective Th1 response of the spleen in the initial phase may explain why splenectomy helps prevent aListeriainfection
Authors: Kuranaga N , Kinoshita M , Kawabata T , Shinomiya N , Seki S
Published: March 2005

Listeria monocytogenes (Listeria) are known to grow and proliferate in the liver while a splenectomy induces host resistance against a Listeria infection despite the fact that a splenectomy inhibits the Th1 response. Therefore, the mechanism by which a splenectomy helps to prevent the growth of Listeria still remains to be elucidated. After an i.v. challenge of Listeria (1 × 106 CFU) in C57BL/6 mice, Listeria rapidly increased in the spleen but not in the liver until 48 h. However, after this initial phase, Listeria remarkably grew in the liver. In contrast, when the mice received a splenectomy beforehand, no remarkable growth of Listeria in the liver was observed after Listeria challenge despite the fact that serum IFN-γ and IL-12 levels at 24 h after Listeria challenge were significantly lower than those in the sham mice. However, the liver leucocytes from mice by 6 h after infection produced a substantial amount of IFN-γ while spleen MNC did not, whereas spleen leucocytes at 24 h after Listeria challenge did. Consistently, the IFN-γ and IL-12 levels in the tissue homogenates of the spleen were significantly lower than in those of the liver until 6 h after infection. This defective spleen Th1 response in the early phase of Listeria infection was corrected by an IL-18 i.p. injection just after the Listeria challenge. Our findings suggest that Listeria exploit the defective Th1 environment of the spleen in the initial phase and afterwards overcome the host defense mechanism of the liver.
Down-regulation of epithelial IL-8 responses inHelicobacter pylori-infected duodenal ulcer patients depends on host factors, rather than bacterial factors
Authors: Strömberg E , Edebo A , Lundin B S , Bergin P , Brisslert M , Svennerholm A M , Lindholm C
Published: March 2005

Helicobacter pylori infection is one of the most common gastrointestinal infections worldwide. Although the majority of the infected individuals remain asymptomatic carriers of the bacteria, approximately 15% develop peptic ulcers, which are most prevalent in the duodenum. H. pylori induce a vigorous immune response which, however, fails to clear the infection. Instead, the chronic inflammation that arises in the infected gastroduodenal mucosa may be involved in the development of H. pylori-associated peptic ulcers. We have previously shown that duodenal ulcer (DU) patients have a significantly lower epithelial cytokine, e.g. IL-8, response in the duodenum than asymptomatic (AS) carriers. In this study we have further investigated the mechanisms behind this finding, i.e. whether it can be explained by bacterial factors, down-regulation of epithelial cytokine production by regulatory T cells, or an impaired ability of the duodenal epithelium in DU patients to produce cytokines. Gastric AGS, and intestinal T84 epithelial cell lines were stimulated with H. pylori strains isolated from DU patients and AS carriers, respectively. All strains were found to induce comparable cytokine and cytokine receptor expression in epithelial cells. Regulatory T cells (CD4+ CD25high), isolated from human peripheral blood and cocultured with H. pylori stimulated AGS cells, were found to slightly suppress H. pylori-induced epithelial cytokine production. Furthermore, primary cultures of duodenal epithelial cells from DU patients were found to produce markedly lower amounts of cytokines than epithelial cells isolated from AS carriers. These results suggest that the lower epithelial cytokine responses in the duodenum of DU patients, which may be of importance for the pathogenesis of H. pylori-induced duodenal ulcers, most likely can be explained by host factors, i.e. mainly a decreased ability of the duodenal epithelium to produce cytokines, but possibly partly also down-regulation by regulatory T cells.
In vivodemonstration of T lymphocyte migration and amelioration of ileitis in intestinal mucosa of SAMP1/Yit mice by the inhibition of MAdCAM-1
Authors: Matsuzaki K , Tsuzuki Y , Matsunaga H , Inoue T , Miyazaki J , Hokari R , Okada Y , Kawaguchi A , Nagao S , Itoh K , Matsumoto S , Miura S
Published: March 2005

The aetiology of Crohn's disease (CD) remains unknown. Since SAMP1/Yit mice have been reported to develop CD-like spontaneous enteric inflammation, such mice have been studied as an animal model of CD. In this study, using this model we examined T lymphocyte migration in microvessels of intestinal mucosa in vivo and the expression of adhesion molecules by immunohistochemistry. Fluorescence-labelled T lymphocytes isolated from AKR/J (control) mice were injected into the tail veins of recipient mice, and T lymphocyte migration in the postcapillary venules of Peyer's patches, submucosal microvessels, and villus capillaries of the terminal ileum was monitored using an intravital microscope. Adhesion of T lymphocytes was significantly increased in 35 week old SAMP1/Yit mice compared with that in AKR/J or 15 week old SAMP1/Yit mice. Immunohistochemical study showed increased infiltration of CD4, CD8 and β7-integrin-positive cells and increased expression of MAdCAM-1 and VCAM-1 in the terminal ileum of SAMP1/Yit mice. Antibodies against MAdCAM-1 and VCAM-1 significantly inhibited adhesion of T lymphocytes to microvessels of the terminal ileum, and anti-MAdCAM-1 antibody showed stronger suppressive effect than the anti-VCAM-1 antibody. Periodical administration of anti-MAdCAM-1 antibody twice a week for 7 weeks significantly ameliorated ileitis of SAMP1/Yit mice, but submucosal hypertrophy was not significantly suppressed. Anti-VCAM-1 antibody treatment failed to show significant resolution of ileitis. In addition, anti-MAdCAM-1 antibody treatment also attenuated established ileitis. The results demonstrate that, although MAdCAM-1 and VCAM-1 play an important role in T lymphocyte–endothelial cell interactions in SAMP1/Yit mice, MAdCAM-1 may be a more appropriate target for therapeutic modulation of chronic ileitis.
Effect ofMycobacterium vaccaeon cytokine responses in children with atopic dermatitis
Authors: Hadley E A , Smillie F I , Turner M A , Custovic A , Woodcock A , Arkwright P D
Published: March 2005

The increasing prevalence of atopic diseases over the last few decades is thought to be due to reduced exposure to environmental microbes that normally down-regulate allergic responses (hygiene hypothesis). We have shown previously that administration of the environmental microbe Mycobacterium vaccae ameliorates atopic dermatitis in school-age children at 3 months post-treatment. The present study tested the hypothesis that M. vaccae suppresses Th2-type cytokine activity and increases transforming growth factor (TGF)-β1 immunomodulatory activity in these children. Interleukin (IL)-4, IL-5, TGF-β1 and interferon (IFN)-γ activity were assessed in resting and stimulated peripheral blood mononuclear cells (PBMC) isolated from 12 of the children who received M. vaccae in our original clinical trial. A cDNA expression array was used to examine a broader range of cytokine pathway transcripts. There were no significant changes in either Th2-type or TGF-β1 activity. A 5- to 10-fold increase in Th1-type activity was found at 1 month post-M. vaccae administration (P < 0·05), but it had returned to baseline by 3 months. The results do not support the hypothesis that M. vaccae reduces Th2-type or increases TGF-β1 activity of PBMC isolated from children with atopic dermatitis. The transient surge in IFN-γ at 1 month is unlikely to explain any improvement in eczema score at 3 months.
Immunostimulatory cellular responses of curedLeishmania-infected patients and hamsters against the integral membrane proteins and non-membranous soluble proteins of a recent clinical isolate ofLeishmania donovani
Authors: Garg R , Gupta S K , Tripathi P , Naik S , Sundar S , Dube A
Published: March 2005

Development of an effective immunoprophylactic agent for visceral leishmaniasis (VL) has become imperative due to the increasing number of cases of drug resistance and relapse. Live and killed whole parasites as well as fractionated and recombinant preparations have been evaluated for vaccine potential. However, a successful vaccine against the disease has been elusive. Because protective immunity in human and experimental leishmaniasis is predominantly of the Th1 type, immunogens with Th1 stimulatory potential would make good vaccine candidates. In the present study, the integral membrane proteins (IMPs) and non-membranous soluble proteins (NSPs), purified from promastigotes of a recent field isolate, Leishmania donovani stain 2001, were evaluated for their ability to induce cellular responses in cured patients (n = 9), endemic controls (n = 5) of visceral leishmaniasis (VL) and treated hamsters (n = 10). IMPs and NSPs induced significant proliferative responses (SI 6·3 ± 4·1 and 5·6 ± 2·3, respectively; P < 0·01) and IFN-γ production (356·3 ± 213·4 and 294·29 ± 107·6 pg/ml, respectively) in lymphocytes isolated from cured VL patients. Significant lymphoproliferative responses against IMPs and NSPs were also noticed in cured Leishmania animals (SI 7·2 ± 4·7 & 6·4 ± 4·1, respectively; P < 0·01). In addition, significant NO production in response both IMPs and NSPs was also noticed in macrophages of hamsters and different cell lines (J774A-1 and THP1). These results suggest that protective, immunostimulatory molecules are present in the IMP and NSP fractions, which may be exploited for development of a subunit vaccine for VL.
Predation by wolves interacts with the North Pacific Oscillation (NPO) on a western North American elk population
Authors: HEBBLEWHITE MARK
Published: March 2005

Recent research reveals the widespread influence of the North Atlantic Oscillation (NAO), a large‐scale climatic variation, on northern ungulate populations. Little is known, however, about the influence of the North Pacific Oscillation (NPO), a similar climatic index, on ungulates.

The influence of the NPO on elk population dynamics in Banff National Park (BNP) was examined using a 15‐year time‐series of three elk subpopulations exposed to different levels of predation by wolves. NPO was strongly related to local climate data including snow depth (r =+0·61) and winter temperatures (r = −0·51).

Higher NPO values reflected increasing winter severity, reducing elk population‐growth rate irrespective of wolf‐predation pressure. Elk population‐growth rate, however, declined more strongly in areas with wolf predation through the interaction with winter severity, indexed by NPO. Effects of NPO were weaker in the absence of wolf predation.

Differences between the effects of snow and NPO were revealed that depended on wolf‐predation pressure. Without wolf predation, NPO reduced elk population‐growth rate, suggesting overall climate was important. With wolf predation, snow depth was more important than NPO, suggesting a mechanism of increased wolf‐predation rates in deeper snow.

This study is the first to demonstrate the influential role of Pacific climate on western North American ungulate population dynamics and provides further evidence of the role of large‐scale climatic variation in terrestrial ecosystem dynamics.
Resource dilution effects on specialist insect herbivores in a grassland biodiversity experiment
Authors: OTWAY STUART J. , HECTOR ANDY , LAWTON JOHN H.
Published: March 2005

The resource concentration hypothesis predicts that specialist insect herbivores attain higher loads (density per unit mass of the host‐plant species) when their food plants grow in high‐density patches in pure stands.

We tested the resource concentration hypothesis for nine specialist insect herbivore species sampled from a field experiment where plant diversity had been manipulated experimentally, generating gradients of host‐plant abundance.

The specialist insects responded to varying host‐plant abundance in two contrasting ways: as expected, specialist herbivore species were more likely to be present when their host‐plant species were abundant; however, counter to predictions, in plots where specialists were present we found strong negative linear relationships between herbivore loads and host‐plant abundances ‐ a ‘resource dilution’ rather than concentration effect.

Increased plant species‐richness had an additional, but weak, negative influence on loads beyond that due to host‐plant abundance.

We discuss the implications of resource dilution effects for biodiversity manipulation experiments and for the study of plant–herbivore interactions more generally.
Lessons from the establishment of exotic species: a meta‐analytical case study using birds
Authors: CASSEY PHILLIP , BLACKBURN TIM M. , DUNCAN RICHARD P. , LOCKWOOD JULIE L.
Published: March 2005

The establishment of species outside their natural geographical ranges is an important driver of changes in global biodiversity. This creates an imperative to understand why some species are more successful than others at establishing viable populations following introduction.

Historical data are particularly useful in this regard, and those for birds especially comprehensive. This has resulted in the publication of regional‐scale studies that have used these data to attempt to quantify relationships between establishment success and characteristics of bird introductions.

We use a meta‐analytical approach to summarize quantitatively the results of these studies, and to assess the influence of variables invoked to explain the variation in establishment success in birds.

We find that variables describing characteristics specific to the individual introduction event (i.e. event‐level variables), such as introduction effort (or ‘propagule pressure’), are the most consistent predictors of establishment success.
Selection for birth date in North Sea haddock and its relation to maternal age
Authors: WRIGHT PETER J. , GIBB FIONA M.
Published: March 2005

Birth date can be important to lifetime reproductive success. However, selection for birth date has rarely been addressed in fish, despite the opportunity provided by otolith microstructure.

This study examined the relationship between maternal age, spawning time and early survivorship in the North Sea haddock stock. Temporal changes in egg production were compared with the birth date distribution of progeny surviving to the demersal phase in 1994, 1996 and 1999, when the age structure of the spawning stock differed.

Estimates of intra‐annual variation in stock egg production indicated that first‐time spawning 2‐year‐olds began spawning much later than older age‐classes.

The form and magnitude of selection on birth date varied between years, indicating that the production of multiple batches of eggs over an extended period has some adaptive significance to progeny survival.

Survivorship was consistently poor from the late spawning period when age 2 females contributed most to stock egg production. This persistent selection against late hatched offspring could reflect either low parental investment, as age 2 females produce smaller eggs, or the short length of the growing season prior to settlement.

Variability in birth date selection, particularly with respect to first vs. subsequent years of spawning, implies a strong selection pressure for a long reproductive lifespan. As such, reproductive potential in this and other exploited fish species with a similar reproductive trait may have been affected adversely by the general decline in repeat spawning females in recent years.
Is there a greater mandibular movement capacity towards the left? Verification of an observation from 1921
Authors: TÜRP J. C. , ALPASLAN C. , GERDS T.
Published: March 2005

summary  In 1921, the German dentist Hans Wertheim reported that more individuals were able to shift the mandible more towards the left than to the right. This study analyses the deviation from symmetrical mobility of the lower jaw in either direction. Using a millimetre ruler, maximum jaw opening (MJO), maximum left laterotrusion (MLL), and maximum right laterotrusion (MRL) were recorded in 141 healthy individuals and in 141 patients with temporomandibular disorders (TMDs). For both sexes, the mean maximum movements to the left and to the right were greater in the healthy group as compared with the TMD group. Healthy subjects as well as patients were able to move the mandible more to one side. Only a minority had identical values for MLL and MRL. The majority of healthy individuals and TMD patients could move more to the left (P < 0·001). In the healthy group, the mean ratio between MJO and MLL was 5·0, and 5·5 between MJO and MRL. In the TMD group, the corresponding values were 4·6 and 6.1. The mean absolute difference between MLL and MLR (in mm) was 1·24 [95% confidence interval (CI): 0·99; 1·49] among healthy females, and 2·09 (95% CI: 1·52; 2·66) among healthy males. In the TMD group, the corresponding values were 2·62 (95% CI: 2·21; 3·04) and 2·83 (95% CI: 1·67; 4·00), respectively. From the results of our study we conclude that moderate deviations from symmetric movements (mean: 1·2 mm for women, 2·1 mm for men) appear to be the norm even in healthy individuals.