bluuebunny/crossref_metadata_2025 huggingface dataset:
Electromagnetic effects on quasilinear turbulent particle transport
Authors: Eriksson Annika , Weiland Jan
Published: September 2005

It is well known that a nonadiabatic part of the electron density response is needed for particle transport in tokamaks. Such main reactive effects are electron trapping and electromagnetic induction. Although electron trapping has been studied rather extensively, electromagnetic effects have hardly been studied at all although they are already included in transport codes. Here the electromagnetic effects have been analyzed and parameter studies have been performed, showing that an electromagnetic particle pinch may appear in the flat density regime, just as for the case of electron trapping although the conditions are more restrictive. The particle pinch is particularly sensitive to the direction of propagation of the eigenmode. The electromagnetic particle flux is found to be outward for modes propagating in the ion drift direction and inward for modes propagating in the electron drift direction. A pinch may be obtained rather close to the axis for International Thermonuclear Experimental Reactor simulation data.
Waveguide array-grating compressors
Authors: Droulias Sotiris , Hizanidis Kyriakos , Christodoulides Demetrios N. , Morandotti Roberto
Published: September 2005

We show that efficient optical pulse compression can be achieved when normally dispersive nonlinear waveguide arrays are used in conjunction with dispersive elements such as gratings or other programmable phase filters. Our computations indicate that the compression resulting from such discrete arrays can be of better quality as compared to that obtained traditionally from a single nonlinear waveguide element. The performance of the array-grating compression method is assessed in normally dispersive highly nonlinear AlGaAs array systems.
Relation between carrier mobility and cell performance in bulk heterojunction solar cells consisting of soluble polythiophene and fullerene derivatives
Authors: Nakamura Jun-ichi , Murata Kazuhiko , Takahashi Kohshin
Published: September 2005

The effect of carrier mobility on the cell performance was examined in the bulk heterojunction solar cells consisting of soluble polythiophene (PHTh) and fullerene derivatives (PCBM). The hole mobility decreased from 6.3×10−3cm2V−1s−1 in the pure PHTh by blending PCBM, while the electron mobility decreased from 2.4×10−2cm2V−1s−1 in the pure PCBM by blending the PHTh. When blending ratio R=PHTh∕(PHTh+PCBM) by weight was 0.5–0.85, ambipolar carrier conduction was possible, showing the best-balanced ambipolar carrier mobility of ca. 10−4cm2V−1s−1 at R=0.7. The power conversion efficiency (η) of the PHTh:PCBM bulk heterojunction solar cells under AM1.5, 85mWcm−2 illumination significantly depended on the blending ratio R and the maximum η of 2.6% was observed at R=0.7, where both electrons and holes are conducting well. Thus, it was concluded that the ambipolar carrier conduction limits the performance of PHTh:PCBM bulk heterojunction solar cells.
The calculation of elastic constants from displacement fluctuations
Authors: Meyers M. T. , Rickman J. M. , Delph T. J.
Published: September 2005

We present a methodology for the accurate and efficient extraction of elastic constants in homogeneous solids via the calculation of the atomic displacement correlation function. This approach is validated for cubic solids parametrized by both Lennard-Jones and embedded-atom method potentials. Finally, we also discuss the extension of this method to obtain the elastic properties of inhomogeneous solids.
Law of the wall of rotating turbulent shear flow
Authors: Park Ju Yeop , Chung Myung Kyoon
Published: September 2005

A possible law of the wall of rotating turbulent shear flow such as a channel in spanwise rotation is investigated. Based on a dimensional analysis and a simple stability theory, functional forms of mixing length in rotating turbulence are derived theoretically for various rates of rotation. Then, a model of mixing length is proposed for the entire rate of rotation and a corresponding law of the wall is obtained for the inner wall region through a numerical integration. The resulting law of the wall is found to show good agreement with both experimental and numerical simulation data.
Vacancy distribution around isolated implantation sites
Authors: Ittermann B. , Füllgrabe M. , Stöckmann H.-J. , Kroll F. , Peters D. , Ackermann H.
Published: September 2005

Microscopic experimental data on the distribution of vacancies created in isolated implantation events are reported for the model system B in Cu. An interstitial-to-substitutional conversion process of the implanted B12 ions is utilized to detect lattice damage. We observe vacancy clouds with well-defined edges and a mean radius of 13.5(9)nm. The radial profile of the local vacancy concentration never exceeds 10−4; it is almost flat in the central region before it falls off rapidly, a behavior which cannot be explained by simple binary-collision computer models.
Increase of island density via formation of secondary ordered islands on pit-patterned Si (001) substrates
Authors: Zhong Z. , Schmidt O. G. , Bauer G.
Published: September 2005

Site-controlled groups of Ge islands are grown on pit-patterned Si (001) substrates. By varying the deposited amount of Ge, we find that the growth starts with the formation of a single island at the pit bottom and then proceeds to the formation of a highly symmetric Ge island group around the pit top. A bimodal size distribution of dome-shaped islands at the bottom and at the top corners of the pits is observed. A growth mechanism is proposed to qualitatively explain these phenomena. Our experiments help to promote a further understanding of Ge island growth on patterned substrates.
Patterned growth of ZnO nanorods by micromolding of sol-gel-derived seed layer
Authors: Kwon S. Joon , Park Jae-Hwan , Park Jae-Gwan
Published: September 2005

An effective method for fabricating micropatterned ZnO nanorods without a catalyst via hydrothermal synthesis using a micromolding technique is presented. Micromolding of a sol-gel-derived seed layer was flawlessly accomplished by conformal contact of elastic mold with microscale pattern. The patterned growth of the nanorods over a large area of the preconfined seed layer was observed with a pattern feasibility attaining 1μm. The orientation of the resulting crystalline nanorods was observed to be normal to the seed layer while characteristic sizes of the nanorods did not show any dependences on the diameter of the seed particles. The presented synthetic process can provide a simpler and more inexpensive way for the fabrication of an array of one-dimensional nanostructures using a wet-chemical method.
Bifurcated converging pathways for high Ca
2
+- and TGFβ-induced inhibition of growth of normal human keratinocytes
Authors: Sakaguchi Masakiyo , Sonegawa Hiroyuki , Nukui Takamasa , Sakaguchi Yoshihiko , Miyazaki Masahiro , Namba Masayoshi , Huh Nam-ho
Published: September 2005

Growth suppression of normal human keratinocytes by high Ca
2
+ or TGFβ was shown to be mediated by p21
WAF1/CIP1
and Sp1 [Pardali, K.,
et al.
(2000)
J. Biol. Chem.
275, 29244–29256; Santini, M. P., Talora, C., Seki, T., Bolgan, L. & Dotto, G. P. (2001)
Proc. Nat. Acad. Sci. USA
98, 9575–9580; Al-Daraji, W. I., Grant, K. R., Ryan, K., Saxton, A., & Reynolds, N. J. (2002)
J. Invest. Dermatol.
118, 779–788]. We previously demonstrated that S100C/A11 is a key mediator for growth inhibition of normal human epidermal keratinocytes (NHK) triggered by high Ca
2+
or TGFβ [Sakaguchi, M.,
et al.
(2003)
J. Cell Biol.
163, 825–835; Sakaguchi, M.,
et al.
(2004) 164, 979–984]. On exposure of NHK cells to either agent, S100C/A11 is transferred to nuclei, where it induces p21
WAF1/CIP1
through activation of Sp1/Sp3. In the present study, we found that high Ca
2+
activated NFAT1 through calcineurin-dependent dephosphorylation. In growing NHK cells, Krueppel-like factor (KLF)16, a member of the Sp/KLF family, bound to the p21
WAF1/CIP1
promoter and, thereby, inhibited the transcription of p21
WAF1/CIP1
. Sp1 complexed with NFAT1 in high Ca
2+
-treated cells or with Smad3 in TGFβ1-treated cells, but not Sp1 alone, replaced KLF16 from the p21
WAF1/CIP1
promoter and transcriptionally activated the

p21
WAF1/CIP1

gene. Thus, high Ca
2+
and TGFβ1 have a common S100C/A11-mediated pathway in addition to a unique pathway (NFAT1-mediated pathway for high Ca
2+
and Smad-mediated pathway for TGFβ1) for exhibiting a growth inhibitory effect on NHK cells, and both pathways were shown to be indispensable for growth inhibition.
VEGF receptor 1 signaling is essential for osteoclast development and bone marrow formation in colony-stimulating factor 1-deficient mice
Authors: Niida Shumpei , Kondo Takako , Hiratsuka Sachie , Hayashi Shin-Ichi , Amizuka Norio , Noda Tetsuo , Ikeda Kyoji , Shibuya Masabumi
Published: September 2005

VEGF receptor 1 (VEGFR-1/Flt-1) is a high-affinity tyrosine kinase (TK) receptor for VEGF and regulates angiogenesis as well as monocyte/macrophage functions. We previously showed that the osteoclast deficiency in osteopetroticCsf1op/Csf1op(op/op) mice is gradually restored in an endogenous, VEGF-dependent manner. However, the molecular basis of the recovery is still not clear. To examine which VEGFR is important and to clarify how colony-stimulating factor 1 (CSF-1) and VEGF signals interact in osteoclastogenesis, we introduced a VEGFR-1 signaling deficiency (Flt1TK-/-) intoop/opmice. The originalFlt1TK-/-mice showed mild osteoclast reduction without bone marrow suppression. The double mutant (op/opFlt1TK-/-) mice, however, exhibited very severe osteoclast deficiency and did not have numbers of osteoclasts sufficient to form the bone marrow cavity. The narrow bone marrow cavity in theop/opFlt1TK-/-mice was gradually replaced with fibrous tissue, resulting in severe marrow hypoplasia and extramedullary hematopoiesis. In addition to osteoclasts, osteoblasts also decreased in number in theop/opFlt1TK-/-mice. These results strongly suggest that the interaction of signals by means of VEGFR-1 and the CSF-1 receptor plays a predominant role not only in osteoclastogenesis but also in the maintenance of bone marrow functions.
Abnormal intrastore calcium signaling in chronic heart failure
Authors: Kubalova Zuzana , Terentyev Dmitry , Viatchenko-Karpinski Serge , Nishijima Yoshinori , Györke Inna , Terentyeva Radmila , da Cuñha Daise N. Q. , Sridhar Arun , Feldman David S. , Hamlin Robert L. , Carnes Cynthia A. , Györke Sandor
Published: September 2005

Diminished Ca release from the sarcoplasmic reticulum (SR) is an important contributor to the impaired contractility of the failing heart. Despite extensive effort, the underlying causes of abnormal SR Ca release in heart failure (HF) remain unknown. We used a combination of simultaneous imaging of cytosolic and SR intraluminal [Ca] in isolated cardiomyocytes and recordings from single-ryanodine receptor (RyR) channels reconstituted into lipid bilayers to investigate alterations in intracellular Ca handling in an experimental model of chronic HF. We found that diastolic free [Ca] inside the SR was dramatically reduced because of a Ca leak across the SR membrane, mediated by spontaneous local release events (Ca sparks), in HF myocytes. Additionally, the magnitudes of intrastore Ca depletion signals during global and focal Ca release events were blunted, and [Ca]
SR
recovery was slowed after global but not focal Ca release in HF myocytes. At the single-RyR level, the sensitivity of RyRs to activation by luminal Ca was greatly enhanced, providing a molecular mechanism for the maintained potentiation of Ca sparks (and increased Ca leak) at reduced intra-SR [Ca] in HF. This work shows that the diminished SR Ca release characteristic of failing myocardium could be explained by increased sensitivity of RyRs to luminal Ca, leading to enhanced spark-mediated SR Ca leak and reduced intra-SR [Ca].
Genome analysis of multiple pathogenic isolates of
Streptococcus agalactiae
: Implications for the microbial “pan-genome”
Authors: Tettelin Hervé , Masignani Vega , Cieslewicz Michael J. , Donati Claudio , Medini Duccio , Ward Naomi L. , Angiuoli Samuel V. , Crabtree Jonathan , Jones Amanda L. , Durkin A. Scott , DeBoy Robert T. , Davidsen Tanja M. , Mora Marirosa , Scarselli Maria , Margarit y Ros Immaculada , Peterson Jeremy D. , Hauser Christopher R. , Sundaram Jaideep P. , Nelson William C. , Madupu Ramana , Brinkac Lauren M. , Dodson Robert J. , Rosovitz Mary J. , Sullivan Steven A. , Daugherty Sean C. , Haft Daniel H. , Selengut Jeremy , Gwinn Michelle L. , Zhou Liwei , Zafar Nikhat , Khouri Hoda , Radune Diana , Dimitrov George , Watkins Kisha , O'Connor Kevin J. B. , Smith Shannon , Utterback Teresa R. , White Owen , Rubens Craig E. , Grandi Guido , Madoff Lawrence C. , Kasper Dennis L. , Telford John L. , Wessels Michael R. , Rappuoli Rino , Fraser Claire M.
Published: September 2005

The development of efficient and inexpensive genome sequencing methods has revolutionized the study of human bacterial pathogens and improved vaccine design. Unfortunately, the sequence of a single genome does not reflect how genetic variability drives pathogenesis within a bacterial species and also limits genome-wide screens for vaccine candidates or for antimicrobial targets. We have generated the genomic sequence of six strains representing the five major disease-causing serotypes of
Streptococcus agalactiae
, the main cause of neonatal infection in humans. Analysis of these genomes and those available in databases showed that the
S. agalactiae
species can be described by a pan-genome consisting of a core genome shared by all isolates, accounting for ≈80% of any single genome, plus a dispensable genome consisting of partially shared and strain-specific genes. Mathematical extrapolation of the data suggests that the gene reservoir available for inclusion in the
S. agalactiae
pan-genome is vast and that unique genes will continue to be identified even after sequencing hundreds of genomes.
Effect of temperature on the working stroke of muscle myosin
Authors: Decostre V. , Bianco P. , Lombardi V. , Piazzesi G.
Published: September 2005

Muscle contraction is due to myosin motors that transiently attach with their globular head to an actin filament and generate force. After a sudden reduction of the load below the maximum isometric force (
T
0
), the attached myosin heads execute an axial movement (the working stroke) that drives the sliding of the actin filament toward the center of the sarcomere by an amount that is larger at lower load and is 11 nm near zero load. Here, we show that an increase in temperature from 2 to 17°C, which increases the average isometric force per attached myosin head by 60%, does not affect the amount of filament sliding promoted by a reduction in force from
T
0
to 0.7
T
0
, whereas it reduces the sliding under low load by 2.5 nm. These results exclude the possibility that the myosin working stroke is due to the release of the mechanical energy stored in the initial endothermic force-generating process and show that, at higher temperatures, the working stroke energy is greater because of higher force, although the stroke length is smaller at low load. We conclude the following: (
i
) the working stroke is made by a series of state transitions in the attached myosin head; (
ii
) the temperature increases the probability for the first transition, competent for isometric force generation; and (
iii
) the temperature-dependent rise in work at high load can be accounted for by the larger free energy drop that explains the rise in isometric force.
On the nonlinear modeling of shot noise
Authors: Eliazar Iddo , Klafter Joseph
Published: September 2005

We introduced a nonlinear shot-noise model, a natural generalization of the “classic” shot-noise model, which differs markedly from the existing linear shot-noise models. This model produces a wide spectrum of stationary noise processes. Because of its intrinsic nonlinearity, the model's resulting noise processes are capable of displaying a rich variety of both amplitudal and temporal statistical behaviors. Surprisingly, the nonlinear model is amenable to mathematical analysis and yields closed-form formulae for the characterizing statistics of its resulting noise processes.
Dual cancer-specific targeting strategy cures primary and distant breast carcinomas in nude mice
Authors: Sarkar Devanand , Su Zao-zhong , Vozhilla Nicolaq , Park Eun Sook , Gupta Pankaj , Fisher Paul B.
Published: September 2005

Limitations of current viral-based gene therapies for malignant tumors include lack of cancer-specific targeting and insufficient tumor delivery. To ameliorate these problems and develop a truly effective adenovirus gene-based therapy for cancer, we constructed a conditionally replication competent adenovirus (CRCA) manifesting the unique properties of tumor-specific virus replication in combination with production of a cancer-selective cytotoxic cytokine, melanoma differentiation associated gene-7/interleukin-24 (
mda
-7/IL-24), which embodies potent bystander antitumor activity. Cancer cell selective tropism was ensured by engineering the expression of the adenoviral E1A protein, necessary for viral replication, under the control of a minimal promoter region of progression elevated gene-3 (PEG-3), which functions selectively in diverse cancer cells with minimal activity in normal cells. In the E3 region of this CRCA, we introduced the
mda
-7/IL-24 gene, thereby mediating robust production of this cytokine as a function of adenovirus replication. Infection of this CRCA (designated Ad.PEG-E1A-
mda
-7) in normal mammary epithelial cells and breast cancer cells confirmed cancer cell selective adenoviral replication,
mda
-7/IL-24 expression, growth inhibition, and apoptosis induction. Injecting Ad.PEG-E1A-
mda
-7 into human breast cancer xenografts in athymic nude mice completely eradicated not only the primary tumor but also distant tumors (established on the opposite flank of the animal) thereby implementing a cure. This dual cancer-specific targeting strategy provides an effective approach for treating breast and other human neoplasms with the potential for eradicating both primary tumors and metastatic disease. Additionally, these studies support the potential use of
mda
-7/IL-24 in the therapy of malignant cancers.
Changing Social Priorities and the Increased Salience of the Economy in Estonia
Authors: Anderson Barbara A. , Romani John H.
Published: September 2005

Since 1991, throughout the former Soviet Union marketization has increased, and much of the social safety net has disappeared. Compared with other former Soviet republics, Estonia has fared well. In this paper, we examine the salience and seriousness of various social issues for groups in Estonia in 1996, and we compare the 1996 results with those of a survey that took place in Estonia in 1991 shortly before the coup. We also reflect on the findings in light of opportunities and challenges for Estonia.
The Gendered Perception of Social Problems in Post-Soviet Estonian Society: A Qualitative Perspective
Authors: Voormann Rein
Published: September 2005

Development in Estonia during the last decade has been very rapid and impressive. Changes that started at the end of 1980s and increased in intensity after Estonia reclaimed its independence in 1991 have completely transformed the face of the country. This rapid political and economic development has been accompanied by several worrying trends. The social cost of the reforms has been high: a decline in living standards, falling birth rates, increasing crime rates, and uneven regional development. Major declines in many other social indicators have occurred as well.
Gender, Work and Economic Restructuring in a Transcarpathia (Ukraine) Village
Authors: Dickinson J. A.
Published: September 2005

This paper combines two sources of qualitative data, focus group interviews and ethnographic research, to discuss gender as a factor in changes to work and identity in a rural Ukrainian village. Analyzing data from focus groups I conducted in the winter and fall of 1997 at my dissertation field site in Transcarpathia, I argue that in this community gender differences are as important as generational differences in shaping participants' evaluation of work opportunities before, during and in particular after the Soviet period. The important relationship between gender and work opportunities in this village stems both from traditional divisions of labor and the loss of professional jobs, such as teaching and administrative positions, available to women during the Soviet period.
Maximum Data Gathering in Networked Sensor Systems
Authors: Hong Bo , Prasanna Viktor K.
Published: September 2005

We focus on data gathering problems in energy-constrained networked sensor systems. We study store-and-gather problems where data are locally stored at the sensors before the data gathering starts, and continuous sensing and gathering problems that model time critical applications. We show that these problems reduce to maximization of network flow under vertex capacity constraint. This flow problem in turn reduces to a standard network flow problem. We develop a distributed and adaptive algorithm to optimize data gathering. This algorithm leads to a simple protocol that coordinates the sensor nodes in the system. Our approach provides a unified framework to study a variety of data gathering problems in networked sensor systems. The performance of the proposed method is illustrated through simulations.
Current Trends in Wireless Sensor Network Design
Authors: Jain Neha , Agrawal Dharma P.
Published: September 2005

The self-organizing nature of sensor networks, their autonomous operation and potential architectural alternatives make them suitable for different data-centric applications. Their wider acceptance seems to be rising on the horizon. In this article, we present an overview of the current state of the art in the field of wireless sensor networks. We also present various open research issues and provide an insight about the latest developments that need to be explored in greater depth that could possibly make this emerging technological area more useful than ever.
Maximizing Data Extraction in Energy-Limited Sensor Networks
Authors: Sadagopan Narayanan , Krishnamachari Bhaskar
Published: September 2005

We examine the problem of maximizing data collection from an energy-limited store-and-extract wireless sensor network, which is analogous to the maximum lifetime problem of interest in continuous data-gathering sensor networks. One significant difference is that this problem requires attention to “data-awareness” in addition to “energy-awareness”. We formulate the maximum data extraction problem as a linear program and present a 1 + ω iterative approximation algorithm for it. As a practical distributed implementation we develop a faster greedy heuristic for this problem that uses an exponential metric based on the approximation algorithm. We then show through simulation results that the greedy heuristic incorporating this exponential metric performs near-optimally (within 1 to 10% of optimal, with low overhead) and significantly better than other energy aware routing approaches (developed mainly through intuition), particularly when nodes are heterogeneous in their energy and data availability.
Dynamic perception in chess
Authors: Ferrari Vincent , Didierjean André , Marmèche Evelyne
Published: September 2005

The present study examines the dynamic aspects of perceptual processes in expert chess players. This topic is approached in terms of the anticipation processes carried out by experienced players during the encoding of chess positions. The aim of the first experiment, which used a short-term comparison task, was to stress the role of anticipation, which allows expert players to focus their attention on the area of the studied position where they expect the likely standard move to occur. The second experiment used a long-term recognition task. The results showed that expert players made many false recognitions on the new positions that could be expected from the positions presented in the preliminary study phase. Taken together, the results of the two experiments highlight the anticipatory component of expert perception.
Effects of age of acquisition and priming on picture naming
Authors: Catling J. C. , Johnston R. A.
Published: September 2005

Four experiments examined the interaction of age of acquisition (AoA) and priming on picture naming. Experiment 1 found that initial-letter priming and AoA significantly affected picture-naming latencies, but there was no interaction between them. Experiment 2 found that initial-phoneme priming and AoA significantly affected picture-naming latencies, but again there was no interaction. Experiment 3 repeated Barry, Hirsh, Johnston, and Williams's (2001) priming study using a very short interval between prime and target. Experiment 3 replicated previous findings of a significant interaction between priming and AoA. Experiment 4 repeated this investigation with a procedure that did not require participants to articulate the prime. Once again, there were significant effects of priming, AoA, and the interaction between them. The implications of these findings in relation to accounts of AoA and its locus of effect are discussed.
Aurora A phosphorylation of TACC3/maskin is required for centrosome-dependent microtubule assembly in mitosis
Authors: Kinoshita Kazuhisa , Noetzel Tim L. , Pelletier Laurence , Mechtler Karl , Drechsel David N. , Schwager Anne , Lee Mike , Raff Jordan W. , Hyman Anthony A.
Published: September 2005

Centrosomes act as sites of microtubule growth, but little is known about how the number and stability of microtubules emanating from a centrosome are controlled during the cell cycle. We studied the role of the TACC3–XMAP215 complex in this process by using purified proteins and Xenopus laevis egg extracts. We show that TACC3 forms a one-to-one complex with and enhances the microtubule-stabilizing activity of XMAP215 in vitro. TACC3 enhances the number of microtubules emanating from mitotic centrosomes, and its targeting to centrosomes is regulated by Aurora A–dependent phosphorylation. We propose that Aurora A regulation of TACC3 activity defines a centrosome-specific mechanism for regulation of microtubule polymerization in mitosis.
Function and regulation of Maskin, a TACC family protein, in microtubule growth during mitosis
Authors: Peset Isabel , Seiler Jeanette , Sardon Teresa , Bejarano Luis A. , Rybina Sonja , Vernos Isabelle
Published: September 2005

The Xenopus protein Maskin has been previously identified and characterized in the context of its role in translational control during oocyte maturation. Maskin belongs to the TACC protein family. In other systems, members of this family have been shown to localize to centrosomes during mitosis and play a role in microtubule stabilization. Here we have examined the putative role of Maskin in spindle assembly and centrosome aster formation in the Xenopus egg extract system. Depletion and reconstitution experiments indicate that Maskin plays an essential role for microtubule assembly during M-phase. We show that Maskin interacts with XMAP215 and Eg2, the Xenopus Aurora A kinase in vitro and in the egg extract. We propose that Maskin and XMAP215 cooperate to oppose the destabilizing activity of XKCM1 therefore promoting microtubule growth from the centrosome and contributing to the determination of microtubule steady-state length. Further more, we show that Maskin localization and function is regulated by Eg2 phosphorylation.
Computational design of recovery experiments for ductile metals
Authors: Bourne N.K , Gray G.T
Published: September 2005

Previous work on the shock loading of metals, has shown that one-dimensional strain histories may be only be approximated in a loaded sample if it is to be recovered at late times to examine microstructure. This proceeds through the use of a system of partial momentum traps and soft, shock-recovery techniques. However, limitations in the degree of uniaxial loading, and on the trapping of tensile pulses, have led to redesign of the target. In the current paper the technique is first assessed, and then modifications are explored to further refine it. Additionally it is illustrated how it may be applied to successfully recover targets of lower innate fracture toughness than has been previously documented. In the first part of the paper, the authors review work undergone to shock recover metals, and highlight associated constraints. In the latter part of the paper, a series of hydrocode simulations is presented to illustrate the design of an improved shock recovery technique that has now been adopted.
Asymptotic distribution method for structural reliability analysis in high dimensions
Authors: Adhikari Sondipon
Published: September 2005

In the reliability analysis of safety critical complex engineering structures, a very large number of the system parameters can be considered as random variables. The difficulty in computing the failure probability using the classical first- and second-order reliability methods (FORM and SORM) increases rapidly with the number of variables or ‘dimension’. There are mainly two reasons behind this. The first is the increase in computational time with the increase in the number of random variables. In principle, this problem can be handled with superior computational tools. The second reason, which is perhaps more fundamental, is that there are some conceptual difficulties typically associated with high dimensions. This means that even when one manages to carry out the necessary computations, the application of existing FORM and SORM may still lead to incorrect results in high dimensions. This paper is aimed at addressing this issue. Based on the asymptotic distribution of quadratic form in Gaussian random variables, two formulations for the case when the number of random variables
n
→∞ is provided. The first is called ‘strict asymptotic formulation’ and the second is called ‘weak asymptotic formulation’. Both approximations result in simple closed-form expressions for the probability of failure of an engineering structure. The proposed asymptotic approximations are compared with existing approximations and Monte Carlo simulations using numerical examples.
A new calculation of the work of formation of bubbles and drops
Authors: Lewins Jeffery
Published: September 2005

The thermodynamic basis of surface tension for bubbles and drops is reformulated to take into account the variation in surface tension for very small, growing or incipient bubbles and drops. After assessing the magnitudes involved by means of conventional theory, a model is put forward for this variation that avoids the supposition of extreme pressures at small sizes in the simple model. The parameter of this new model is then set by consideration of the properties of real gases, determined by analysis of the incipient bubble and then extended, it is argued, to the incipient drop. van der Waals' model of a real gas is used to show how this combines with the Lewins model in a self-consistent approach to the thermodynamics of surface tension for bubbles and drops. The changes from the simple theory will then allow a revision of the dynamic statistical theory of auto-nucleation and a reassessment of the critical sizes for imposed or heterogeneous nucleation, based on a simple and self-consistent thermodynamic model.
A Borg–Levinson theorem for trees
Authors: Brown B.M , Weikard R
Published: September 2005

We prove that the Dirichelet-to-Neumann map for a Schrödinger operator on a finite simply connected tree determines uniquely the potential on that tree.
Integrable discrete differential geometry of ‘plated’ membranes in equilibrium
Authors: Schief W.K
Published: September 2005

Recently, it has been established that a well-known system of classical shell theory descriptive of membranes in equilibrium is, in fact, amenable to the techniques of soliton theory. Here, it is demonstrated that its canonical discrete counterpart governing ‘plated’ membranes in equilibrium is likewise integrable in that it admits both a parameter-dependent linear representation (Lax pair) and a Bäcklund transformation.
Assessing putative interlocus sexual conflict in
Drosophila melanogaster
using experimental evolution
Authors: Stewart Andrew D , Morrow Edward H , Rice William R
Published: September 2005

The theoretical foundation of sexually antagonistic coevolution is that females suffer a net fitness cost through their interactions with males. The empirical prediction is that direct costs to female lifetime fecundity will exceed indirect benefits despite a possible increase in the genetic quality of offspring. Although direct costs of males have been repeatedly shown, to date no study has comprehensively tested whether females are compensated for this direct harm through indirect benefits. Here we use experimental evolution to show that a mutation giving
Drosophila melanogaster
females nearly complete resistance to the direct costs of male courtship and remating, but which also excluded almost all indirect benefits, is strongly favoured by selection. We estimated the selection coefficient favouring the resistance allele to be +20%. These results demonstrate that any indirect benefits that females accrued were not sufficient to counter-balance the direct costs of males, and reinforce a large body of past studies by verifying interlocus sexual conflict in this model system.
Phylogenetic relationships and the primitive X chromosome inferred from chromosomal and satellite DNA analysis in Bovidae
Authors: Chaves Raquel , Guedes-Pinto Henrique , Heslop-Harrison John S
Published: September 2005

The early phylogeny of the 137 species in the Bovidae family is difficult to resolve; knowledge of the evolution and relationships of the tribes would facilitate comparative mapping, understanding chromosomal evolution patterns and perhaps assist breeding and domestication strategies. We found that the study of the presence and organization of two repetitive DNA satellite sequences (the clone pOaKB9 from sheep, a member of the 1.714 satellite I family and the pBtKB5, a 1.715 satellite I clone from cattle) on the X and autosomal chromosomes by
in situ
hybridization to chromosomes from 15 species of seven tribes, was informative. The results support a consistent phylogeny, suggesting that the primitive form of the X chromosome is acrocentric, and has satellite I sequences at its centromere. Because of the distribution of the ancient satellite I sequence, the X chromosome from the extant Tragelaphini (e.g. oryx), rather than Caprini (sheep), line is most primitive. The Bovini (cow) and Tragelaphini tribes lack the 1.714 satellite present in the other tribes, and this satellite is evolutionarily younger than the 1.715 sequence, with absence of the 1.714 sequence being a marker for the Bovini and Tragelaphini tribes (the Bovinae subfamily). In the other tribes, three (Reduncini, Hippotragini and Aepycerotini) have both 1.714 and 1.715 satellite sequences present on both autosomes and the X chromosome. We suggest a parallel event in two lineages, leading to X chromosomes with the loss of 1.715 satellite from the Bovini, and the loss of both 1.714 and 1.715 satellites in a monophyletic Caprini and Alcelaphini lineage. The presence and X chromosome distribution of these satellite sequences allow the seven tribes to be distributed to four groups, which are consistent with current diversity estimates, and support one model to resolve points of separation of the tribes.
Quantitative evaluation of oxidative stress status on peripheral blood in β‐thalassaemic patients by means of electron paramagnetic resonance spectroscopy
Authors: Filosa A. , Valgimigli L. , Pedulli G. F. , Sapone A. , Maggio A. , Renda D. , Scazzone C. , Malizia R. , Pitrolo L. , Lo Pinto C. , Borsellino Z. , Cuccia L. , Capra M. , Canistro D. , Broccoli M. , Soleti A. , Paolini M.
Published: September 2005

High oxidative stress status (OSS) is known to be one of the most important factors determining cell injury and consequent organ damage in thalassaemic patients with secondary iron overload. Using an innovative hydroxylamine ‘radical probe’ capable of efficiently trapping majority of oxygen‐radicals including superoxide we measured, by electron paramagnetic resonance (EPR) spectroscopy, OSS in peripheral blood of 38 thalassaemic patients compared with sex‐/age‐matched healthy controls. Thalassaemic patients showed sixfold higher EPR values of OSS than controls. Significantly higher EPR values of OSS were observed in those with a severe phenotype (thalassaemia major, transfusion‐dependent) with respect to mild phenotype (sickle‐cell/β‐thalassaemia, not transfusion‐dependent) or thalassaemia intermedia. In patients with thalassaemia major, EPR values of OSS were positively correlated with serum ferritin and with alanine aminotransferase levels. In patients with sickle cell/β‐thalassaemia, there was no correlation between EPR value of OSS and all parameters considered. The type of chelating therapy (desferrioxamine or deferiprone) did not have an effect on EPR value of OSS. In conclusion, EPR ‘radical probe’ seems to be a valid innovative method to determine total OSS in patients affected by thalassaemia and might be used for evaluating new strategies of chelation, new chelators, or the efficacy of antioxidant formula.
Cloning and functional expression of venom prothrombin activator protease from Pseudonaja textilis with whole blood procoagulant activity
Authors: Filippovich Igor , Sorokina Natasha , Pierre Liam St , Flight Simone , Jersey John de , Perry Naomi , Masci Paul P. , Lavin Martin F.
Published: September 2005

The snake venom group C prothrombin activators contain a number of components that enhance the rate of prothrombin activation. The cloning and expression of full‐length cDNA for one of these components, an activated factor X (factor Xa)‐like protease from Pseudonaja textilis as well as the generation of functional chimeric constructs with procoagulant activity were described. The complete cDNA codes for a propeptide, light chain, activation peptide (AP) and heavy chain related in sequence to mammalian factor X. Efficient expression of the protease was achieved with constructs where the AP was deleted and the cleavage sites between the heavy and light chains modified, or where the AP was replaced with a peptide involved in insulin receptor processing. In human kidney cells (H293F) transfected with these constructs, up to 80% of the pro‐form was processed to heavy and light chains. Binding of the protease to barium citrate and use of specific antibodies demonstrated that γ‐carboxylation of glutamic acid residues had occurred on the light chain in both cases, as observed in human factor Xa and the native P. textilis protease. The recombinant protease caused efficient coagulation of whole citrated blood and citrated plasma that was enhanced by the presence of Ca2+. This study identified the complete cDNA sequence of a factor Xa‐like protease from P. textilis and demonstrated for the first time the expression of a recombinant form of P. textilis protease capable of blood coagulation.
Advances in the understanding of the congenital dyserythropoietic anaemias
Authors: Wickramasinghe Sunitha N. , Wood William G.
Published: September 2005

The congenital dyserythropoietic anaemias (CDAs) are a heterogeneous group of diseases in which the anaemia is predominantly caused by dyserythropoiesis and marked ineffective erythropoiesis; three major (types I, II and III) and several minor subgroups have been identified. Additional information on the natural history of these conditions, the beneficial role of splenectomy in CDA type II and efficacy of interferon‐α in type I have recently been reported. A disease gene has been localised to a chromosomal segment in the three major types and in CDA type I, a disease gene has been identified (CDANI). Mutations have been detected in both familial and sporadic cases but the predicted protein structure gives few clues as to its function. In both type I and II, there are cases unlinked to the identified localisations, suggesting genetic heterogeneity.
JAK2V617F mutation in essential thrombocythaemia: clinical associations and long‐term prognostic relevance
Authors: Wolanskyj Alexandra P. , Lasho Terra L. , Schwager Susan M. , McClure Rebecca F. , Wadleigh Martha , Lee Stephanie J. , Gary Gilliland D. , Tefferi Ayalew
Published: September 2005

Clinical correlates and long‐term prognostic relevance of the JAK2V617F mutation was studied in 150 patients with essential thrombocythaemia (ET) from a single institution and followed for a median of 11·4 years. During this period, thrombotic complications were documented in 62 patients (41·3%) and transformation into acute myeloid leukaemia (AML), polycythaemia vera (PV), or myelofibrosis with myeloid metaplasia (MMM) occurred in 4 (2·7%), 8 (5·3%), and 15 (10%) patients, respectively. JAK2V617F was detected in either archived bone marrow or blood cells from 73 patients (48·7%) but none were homozygous for the mutant allele. Parameters at diagnosis that were significantly associated with the presence of JAK2V617F included advanced age and higher counts of both haemoglobin and leucocytes. During follow‐up, patients with the mutation were more likely to transform into PV but the incidences of AML, MMM, or thrombotic events were similar between patients with and without the mutation. Multivariate analysis identified advanced age, higher haemoglobin level, and thrombosis history but not the presence of JAK2V617F as independent predictors of inferior survival. Therefore, although the presence of JAK2V617F in ET appears to promote a PV phenotype, it might not carry treatment‐relevant information.
Dissemination of fat in CSF: a common finding following translabyrinthine acoustic neuroma surgery*
Authors: Ray J. , D'Souza A.R. , Chavda S.V. , Walsh A.R., , Irving R.M.
Published: September 2005

Objectives:  Following translabyrinthine craniotomy the temporal bone defect is commonly obliterated using a free autologous fat graft. In this series the dura was put back in place but not closed primarily. As the fat graft remains in direct contact with the cerebro spinal fluid (CSF) there is potential for dispersal of fat within the CSF space. This paper aims to determine the frequency of such CSF fat dissemination and its clinical significance.

Design:  A retrospective review of translabyrinthine acoustic neuroma removal with free fat autograft obliteration of the temporal bone defect between the years 1997 and 2000.

Setting:  Tertiary referral oto‐neurosurgical centre. Postoperative magnetic resonance (MR) imaging.

Participants:  All translabyrinthine patients who had postoperative MR imaging were included. Twenty‐six cases were identified. Age range was 13–70 years. Fourteen were male patients.

Main outcome measures:  Evidence of CSF fat dissemination on MR and patients’ clinical findings.

Results:  Twenty‐two of the 26 scans (85%) demonstrated evidence of fat dissemination into the subarachnoid CSF spaces in the form of microemboli. The cerebellopontine angle was the most common site involved. No evidence of ventricular dilation or any other abnormality was noted. There was no relationship between the presence or extent of fat microembolization and the patients’ clinical course.

Conclusions:  This study suggests that free fat placed in temporal bone defects commonly migrate into the subarachnoid space and subsequently move around in these spaces. This is not associated with any complications such as hydrocephalus, meningitis or prolonged postoperative headache.
How we do it: BAHA positioning in patients with microtia requiring auricular reconstruction
Authors: Bajaj Y. , Wyatt M.E. , Gault D. , Bailey C.M. , Albert D.M.
Published: September 2005

Keypoints

Bilateral microtia is a challenging problem as these patients require both reconstruction of the auricle and rehabilitation of hearing.

Our aim was to find the optimal position for bone‐anchored hearing aids (BAHA) in patients requiring reconstruction of the auricle on the same side.

From an analysis of five such operated patients, it was found that siting a BAHA 6.5–7.0 cm from the position of the external auditory meatus is probably the correct distance to facilitate optimal auricular reconstruction.

Using these criteria, a group of another five patients with BAHA awaiting auricular reconstruction were reviewed. Of these only three (60%) have been satisfactorily sited.
How we do it: Free conchal cartilage revisited for primary reconstruction of attic defects in combined approach tympanoplasty
Authors: Koury E. , Faris C. , Sharma S. , Quinn S.J.
Published: September 2005

Keypoints

There are concerns over the efficacy of free cartilage autografts in attic reconstruction (scutumplasty) for combined approach tympanoplasty (CAT).

Our operative technique uses free conchal cartilage autografts and an additional piece of conchal cartilage to buttress the reconstruction.

Of the 16 cases where this technique was used, there were two cases (13%) of failure of the attic reconstruction and a keratin pearl (residual disease) in one case (6%). This compares favourably with comparable series using a variety of reconstruction techniques.
How we do it: ionomeric cement to attach the stapes prosthesis to the long process of the incus
Authors: Tysome J.R. , Harcourt J.
Published: September 2005

Keypoints

The successful use of glass–ionomeric cement in primary stapes surgery for attachment of the wire loop of the stapes prosthesis to the long process of the incus is reported.

Early hearing outcomes were similar in patients where cement was used for stapes prosthesis attachment compared with those with standard wire crimping technique.

Use of glass–ionomeric cement to attach the stapes prosthesis to the incus may prevent stapes prosthesis displacement and loosening.

This technique may decrease rates of revision stapes surgery and allow the safe use of magnetic resonance image scanning.
How we do it: Modified Wehrs incus ossiculoplasty
Authors: Al‐Qudah M. , Dawes P.J.D.
Published: September 2005

Keypoints

Ossiculoplasty is commonly performed as part of tympanoplasty. Hydroxyapatite is a favoured material for ossicular protheses.

A modification to the Wehrs incus prosthesis® is described.

Twenty‐one procedures were performed on 20 patients and the results are reported.

On average there was a 4–5 dB closure of the air–bone gap (ABG), with patients having a hearing gain procedure averaging 11 dB closure. Air–bone gap closure to ≤20 dB was achieved between 78% (0.5, 1, 2 kHz average) and 60% (0.5, 1, 2, 4 kHz average) of patients and this was stable during long‐term follow‐up of the ABG.

Wehrs incus prosthesis® ossiculoplasty provides a reliable result following ossiculoplasty when autograft incus is not available.
Nasal surgery and eustachian tube function: effects on middle ear ventilation
Authors: Salvinelli F. , Casale M. , Greco F. , D'Ascanio L. , Petitti T. , Di Peco V.
Published: September 2005

Objectives:  To investigate the effect of nasal obstruction surgery on eustachian tube function and middle ear ventilation.

Design:  Prospective study.

Setting:  University Campus Bio‐Medico of Rome.

Participants:  Forty consecutive patients who underwent nasal surgery were evaluated for middle ear ventilation and tubal function.

Main outcome measures:  Pre‐ and postoperative Valsalva and Toynbee tubal function tests, tympanometry and ear fullness sensation were evaluated for both ears of each patient.

Results:  Results of postoperative tubal function tests were significantly better than preoperative ones (90% versus 46%; P < 0.001). No significant difference in tympanometric values was found. The majority (95%) of the patients reported a postoperative improvement of ear fullness sensation compared with preoperative (25%; P < 0.001).

Conclusions:  Surgery for chronic nasal obstruction significantly improves clinical tubal function but 1‐month postoperative tympanometric findings remain almost the same.