bluuebunny/crossref_metadata_2025 huggingface dataset:
Chitosan‐modified nanoclay–poly(AMPS) nanocomposite hydrogels with improved gel strength
Authors: Kabiri Kourosh , Mirzadeh Hamid , Zohuriaan‐Mehr Mohammad J , Daliri Morteza
Published: September 2009

BACKGROUND: Making (nano)composite structures is one of the efficient approaches for strengthening hydrogels extended in recent years. The present paper deals with the synthesis and properties of novel nanocomposite hydrogels based on 2‐acrylamido‐2‐methylpropane‐1‐sulfonic acid (AMPS). Initially, a bio‐modified clay, chitosan‐intercalated montmorillonite (chitoMMT), was prepared. Then, this was incorporated into the polymerization of AMPS in the presence of a macro‐crosslinker, i.e. poly(ethylene glycol) dimethacrylate, to yield super‐swelling nanocomposite hydrogels. The swelling capacity as well as some structural, rheological and thermomechanical properties of the hydrogels were studied and compared with those of the clay‐free counterpart.

RESULTS: ChitoMMT exhibited no toxicity, which was confirmed using cell‐culture testing. A chitoMMT content of ca 6% was found to be the most favourable content of the bio‐modified clay for achieving a product with improved properties (i.e. the highest gel content, the highest gel strength and optimal thermal stability). Based on a dynamic mechanical thermal analysis study, an increased glass transition temperature (98.2 °C) and improved rubbery modulus (up to 238% higher than that of the clay‐free counterpart) were recorded. Thermogravimetric analysis verified that the thermal stability of nanocomposite samples was higher than that of clay‐free samples.

CONCLUSION: Owing to the non‐toxicity of the incorporated chitoMMT, the strengthened hydrogels may be considered as potential candidates for bio‐applications. Copyright © 2009 Society of Chemical Industry
Visibly observed photocrosslinking reaction in indolyl based pendant liquid crystalline polymers: Synthesis and optical property
Authors: Gayathri Kumarasamy , Saravanan Chinnusamy , Kannan Palaninathan
Published: September 2009

Visibly observed photocrosslinkable pendant liquid crystalline polymers containing indolyl based chalcone were synthesized by free‐radical polymerization and characterized spectroscopically. The differential scanning calorimetry and polarized optical microscopy were used to examine liquid crystalline property. The photocrosslinking and luminescence properties were monitored by UV‐Vis spectrophotometer and spectrofluorimeter, respectively. It demonstrates the chalcone unit did not manifest cis ↔ trans‐isomerization reaction along with 2π+2π photodimerization upon irradiation with UV light like other chalcones hitherto reported. The photocrosslinking was visibly monitored in solution through change of fluorescent color to colorless. The spacer lengths play a key role in the reaction. The fluorescence maximum was blue shifted around 70 nm in chloroform solution upon irradiation with UV light confirms the 2π+2π photodimerization of chalcone unit. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5208–5220, 2009
An observation‐space formulation of variational assimilation using a restricted preconditioned conjugate gradient algorithm
Authors: Gratton Serge , Tshimanga Jean
Published: September 2009

We consider parameter estimation problems involving a set of m physical observations, where an unknown vector of n parameters is defined as the solution of a nonlinear least‐squares problem. We assume that the problem is regularized by a quadratic penalty term. When solution techniques based on successive linearization are considered, as in the incremental four‐dimensional variational (4D‐Var) techniques for data assimilation, a sequence of linear systems with particular structure has to be solved. We exhibit a subspace of dimension m that contains the solution of these linear systems, and derive a variant of the conjugate gradient algorithm that is more efficient in terms of memory and computational costs than its standard form, when m is smaller than n. The new algorithm, which we call the Restricted Preconditioned Conjugate Gradient (RPCG), can be viewed as an alternative to the so‐called Physical‐space Statistical Analysis System (PSAS) algorithm, which is another approach to solve the linear problem. In addition, we show that the non‐monotone and somehow chaotic behaviour of PSAS algorithm when viewed in the model space, experimentally reported by some authors, can be fully suppressed in RPCG.

Moreover, since preconditioning and re‐orthogonalization of residuals vectors are often used in practice to accelerate convergence in high‐dimension data assimilation, we show how to reformulate these techniques within subspaces of dimension m in RPCG. Numerical experiments are reported, on an idealized data assimilation system based on the heat equation, that clearly show the effectiveness of our algorithm for large‐scale problems. Copyright © 2009 Royal Meteorological Society
Hepatic Expression of Long‐Chain Acyl‐CoA Synthetase 3 is Upregulated in Hyperlipidemic Hamsters
Authors: Wu Minhao , Liu Haiyan , Chen Wei , Fujimoto Yasuyuki , Liu Jingwen
Published: September 2009

Members of the mammalian long‐chain acyl‐CoA synthetase (ACSL) family are key enzymes for cellular fatty acid metabolism that catalyze the initial step in activation of long‐chain fatty acids. However, the specificity of individual isoforms of ACSL to the lipid metabolic process is not well studied. In addition, the regulation of expression of individual ACSL isoforms under hyperlipidemic conditions is largely unknown. We cloned the hamster ACSL3 cDNA coding region and generated specific antibodies recognizing the ACSL3 protein. We next observed the changes in ACSL3 mRNA and protein expression in hamsters fed a standard chow diet or a high fat and high cholesterol (HFHC) diet. HFHC feeding significantly increased ACSL3 mRNA and protein expression in liver and to a lesser extent in muscle but not in adipose, brain, heart, or testis. Additionally, ACSL3 mRNA abundance was differentially regulated by the nutritional status in different tissues with liver, muscle, and adipose being the most sensitive tissues. Importantly, the hepatic ACSL3 mRNA expression pattern in response to fasting and refeeding in hyperlipidemic hamsters differed from that observed in normal chow‐fed hamsters. Together, these results provide the first in vivo evidence of altered regulation of hepatic ACSL3 expression under hyperlipidemic conditions and suggest important regulatory roles for this enzyme in lipid metabolism.
The longitudinal change in anthropometric measurements and the association with physical function decline in Japanese community-dwelling frail elderly
Authors: Izawa Sachiko , Enoki Hiromi , Hirakawa Yoshihisa , Iwata Mitsunaga , Hasegawa Jun , Iguchi Akihisa , Kuzuya Masafumi
Published: September 2009

Although anthropometric parameters have been extensively studied regarding their relationship to physical function status, the association between these parameters and the activity of daily living (ADL) function remains controversial. We investigated whether BMI or mid-upper arm circumference (AC) is an indication of variation in the physical functioning of the frail elderly. The present study was a prospective cohort analysis of 543 community-dwelling frail elderly. Data included the participants' demographic characteristics, basic ADL, comorbidity and anthropometric measurements at baseline and at 2-year follow-up. Logistic regression models were used to investigate the association between ADL status and anthropometric measurements during the study period. Among the 543 participants, 418 maintained or improved their ADL status, while 125 showed an ADL decline during the study period. Multivariate logistic regression analysis showed that BMI and AC levels or ADL status at baseline were not independent predictors of the loss of ADL function or the decline in these anthropometric measurements during the study period, respectively. However, the decline in BMI and AC levels and the loss of ADL function were associated with each other during the study period. There is an association between the negative changes in anthropometric measurements during the follow-up period and the decline in ADL function during a 2-year follow-up in community-dwelling frail elderly.
Correlation for the Lower Palaeozoic
Authors: COCKS L. ROBIN M. , FORTEY RICHARD A. , RUSHTON ADRIAN W. A.
Published: September 2009

The global correlation standards now agreed for the Ordovician and Silurian systems, and partly so for the Cambrian System, are summarized. Correlation of the international series and stages with the traditional and revised British series and stages is reviewed, as well as with those in North America (Laurentia).
Herodotus at Cambridge: With Samuel Butler and Enoch Powell
Authors: WEST M. L.
Published: September 2009

The many-sided and lively-minded writer Samuel Butler (1835–1902) attended St John's College, Cambridge, from 1854 to 1858. There he penned a brief account of College rowing in the manner of Herodotean ethnography. It was preserved by a friend and published posthumously.
Viscous simulation of shock-reflection hysteresis in overexpanded planar nozzles
Authors: SHIMSHI E. , BEN-DOR G. , LEVY A.
Published: September 2009

A computational fluid dynamics simulation of the flow in an overexpanded planar nozzle shows the existence of Mach-reflection hysteresis inside the nozzle. Previous simulations have dealt only with the flow outside the nozzle and thus concluded that the hysteresis phenomenon takes place outside the nozzle even when viscous effects are introduced. When including the geometry of the nozzle in the simulation it becomes evident that flow separation will occur before the transition from regular to Mach reflection for all relevant Mach numbers. The simulation reveals complex changes in the flow structure as the pressure ratio between the ambient and the jet is increased and decreased. The pressure along the nozzle wall downstream of the separation point is found to be less than the ambient pressure, and a modification of the Schilling curve fit is suggested for cases of extensive flow separation.
‘Born out of crisis’: Assessing the Legacy of the Exmoor Moorland Management Agreements
Authors: LOBLEY MATT , WINTER MICHAEL
Published: September 2009

Shortly after the designation of Exmoor National Park in 1954 the moorland that the park was charged with maintaining and enhancing came under threat from agricultural improvement. The ensuing ‘moorland conflict’ eventually led to a pioneering system of moorland management agreements. The moorland management agreements have an important place in the transformation of agricultural policy and the development and social acceptance amongst farmers and landowners of the concept that farmers should be paid for their stewardship of the environment. Drawing on published and unpublished documents, as well as extensive interviews, this paper revisits the origins of the problem of moorland reclamation, assesses the role played by key individuals in publicising the problem and promoting management agreements as a solution, considers the risks taken by those entering into management agreements, and identifies some of the tangible and intangible impacts of the moorland management agreement system.
The λ-calculus with constructors: Syntax, confluence and separation
Authors: ARBISER ARIEL , MIQUEL ALEXANDRE , RÍOS ALEJANDRO
Published: September 2009

We present an extension of the λ(η)-calculus with a case construct that propagates through functions like a head linear substitution, and show that this construction permits to recover the expressiveness of ML-style pattern matching. We then prove that this system enjoys the Church–Rosser property using a semi-automatic ‘divide and conquer’ technique by which we determine all the pairs of commuting subsystems of the formalism (considering all the possible combinations of the nine primitive reduction rules). Finally, we prove a separation theorem similar to Böhm's theorem for the whole formalism.
The Regular Excluded Minors for Signed-Graphic Matroids
Authors: QIN HONGXUN , SLILATY DANIEL C. , ZHOU XIANQQIAN
Published: September 2009

We show that the complete list of regular excluded minors for the class of signed-graphic matroids isM*(G1),. . . ,M*(G29),R15,R16. HereG1,. . . ,G29are the vertically 2-connected excluded minors for the class of projective-planar graphs andR15andR16are two regular matroids that we will define in the article.
COMMISSION 30: Radial Velocities
Authors: Nordström Birgitta , Udry Stephane , Dravins D. , Fekel F. , Glushkova E. , Levato H. , Pourbaix D. , Smith M.A. , Szabados L. , Torres G.
Published: September 2009

This report from Commission 30 covers the salient areas in which major progress has been made in the triennium covered by the present volume. The principal scientific areas are: The Milky Way, star clusters, spectroscopic binaries, extrasolar planets, pulsating stars and stellar oscillations. Following these, an account is given of the progress in techniques and methodology for radial velocity determinations. Finally, a summary is given of the progress made by the working groups of the Commission, followed by a list of key papers in the triennium. A more extensive report also covering extragalactic work, which due to unforeseen circumstances could not be included here, can be found at the web page of Commission 30 (http://www.iau.org/IAU/Organization/divcom/).
Possible deep fault slip preceding the 2004 Parkfield earthquake, inferred from detailed observations of tectonic tremor
Authors: Shelly David R.
Published: September 2009

Earthquake predictability depends, in part, on the degree to which sudden slip is preceded by slow aseismic slip. Recently, observations of deep tremor have enabled inferences of deep slow slip even when detection by other means is not possible, but these data are limited to certain areas and mostly the last decade. The region near Parkfield, California, provides a unique convergence of several years of high‐quality tremor data bracketing a moderate earthquake, the 2004 magnitude 6.0 event. Here, I present detailed observations of tectonic tremor from mid‐2001 through 2008 that indicate deep fault slip both before and after the Parkfield earthquake that cannot be detected with surface geodetic instruments. While there is no obvious short‐term precursor, I find unidirectional tremor migration accompanied by elevated tremor rates in the 3 months prior to the earthquake, which suggests accelerated creep on the fault ∼16 km beneath the eventual earthquake hypocenter.
Volume versus surface-mediated recombination in anatase TiO2 nanoparticles
Authors: Cavigli Lucia , Bogani Franco , Vinattieri Anna , Faso Valentina , Baldi Giovanni
Published: September 2009

We present an experimental study of the radiative recombination dynamics in size-controlled anatase TiO2 nanoparticles in the range 20–130 nm. From time-integrated photoluminescence spectra and picosecond time-resolved experiments as a function of the nanoparticle size, excitation density, and temperature, we show that photoluminescence comes out from a bulk and a surface radiative recombination. The spectral shift and the different time dynamics provide a clear distinction between them. Moreover, the intrinsic nature of the emission is also proven, providing a quantitative evaluation of volume and surface contributions.
Structural properties of buried conducting layers formed by very low energy ion implantation of gold into polymer
Authors: Teixeira F. S. , Salvadori M. C. , Cattani M. , Brown I. G.
Published: September 2009

We have investigated the fundamental structural properties of conducting thin films formed by implanting gold ions into polymethylmethacrylate (PMMA) polymer at 49 eV using a repetitively pulsed cathodic arc plasma gun. Transmission electron microscopy images of these composites show that the implanted ions form gold clusters of diameter ∼2–12 nm distributed throughout a shallow, buried layer of average thickness 7 nm, and small angle x-ray scattering (SAXS) reveals the structural properties of the PMMA-gold buried layer. The SAXS data have been interpreted using a theoretical model that accounts for peculiarities of disordered systems.
Effect of gas flow on the growth of In-rich AlInN films by metal-organic chemical vapor deposition
Authors: Kang Ting-Ting , Yamamoto Masatomo , Tanaka Mikiyasu , Hashimoto Akihiro , Yamamoto Akio
Published: September 2009

Indium-rich AlInN are grown by metal-organic (MO) chemical vapor deposition using trimethylaluminum, trimethylindium, and ammonia. Under the conservation of MO influx, the effects of gas flow in the MO route on AlInN growth and Al-related parasitic reaction are investigated. With an increase in this gas flow, the suppression of Al-related parasitic reaction, i.e., enhancement in Al content incorporation and improvement of crystalline quality, is satisfactorily shown until the occurring of severe phase separation. Accordingly, Al content x in AlxIn1−xN can be tuned from x=0.02 to 0.26. The Raman spectra of those AlInN samples with phase separation are analyzed by the resonant excitation effect and two-mode behavior for A1(LO). Finally, we propose a phase diagram to interpret the phase separation and Al content evolution under the influence of gas flow.
Anisotropic composite right/left-handed-material switch
Authors: Ionita I. , Dragoman D.
Published: September 2009

It is shown that an anisotropic composite structure, which consists of alternating layers with either negative permittivity or negative permeability, can switch between optical responses characteristic of right-handed and left-handed materials depending on the polarization (TE or TM) of the incident electromagnetic field. The switching possibility is maintained for a small angular range around normal incidence, the behavior of the structure for larger incidence angles showing superluminal group velocities characteristic for anisotropic metamaterials.
Extraction of semiconductor microchip differential gain by use of optically pumped semiconductor laser
Authors: Walton Matthew , Terry Nathan , Hader Jorg , Moloney Jerome , Bedford Robert
Published: September 2009

The small-signal modulation response of a vertical external cavity surface emitting laser is analyzed to determine its resonance frequency in relation to photon density, allowing nondestructive extraction of characteristic parameters of chips, such as internal loss and differential gain.
Bandgap and band offsets determination of semiconductor heterostructures using three-terminal ballistic carrier spectroscopy
Authors: Yi Wei , Narayanamurti Venkatesh , Lu Hong , Scarpulla Michael A. , Gossard Arthur C. , Huang Yong , Ryou Jae-Hyun , Dupuis Russell D.
Published: September 2009

Utilizing ambipolar tunnel emission of ballistic electrons and holes, we have developed a model-independent method to self-consistently measure bandgaps of semiconductors and band offsets at semiconductor heterojunctions. Lattice-matched GaAs/AlxGa1−xAs and GaAs/(AlxGa1−x)0.51In0.49P (100) single-barrier heterostructures are studied at 4.2 K. For the GaAs/AlGaAs interface, the measured Γ band offset ratio is 60.4:39.6 (±2%). For the heteroanion GaAs/AlGaInP (100) interface, this ratio varies with the Al composition and is distributed more in the valence band. The indirect-gap X band offsets observed at the GaAs/AlGaInP interface deviates from predictions by the transitivity rule.
Terahertz generation and chaotic dynamics in single-walled zigzag carbon nanotubes
Authors: Wang C. , Cao J. C.
Published: September 2009

We study self-sustained terahertz current oscillation and chaotic dynamics in semiconducting single-walled zigzag carbon nanotubes using the time-dependent drift diffusion equations. The current oscillation under a dc voltage bias originates from the negative differential velocity of carbon nanotube which induces the motion and recycling of unstable domain. Numerical simulation indicates that different nonlinear oscillatory modes appear when an external high-frequency ac voltage is superimposed to the dc voltage bias and its driving amplitude varies. The appearance of different nonlinear oscillating modes, including periodic and chaotic, is attributed to the competition between the natural oscillation and the external driving oscillation. The transitions between periodic and chaotic states are carefully studied using chaos-detecting methods, such as bifurcation diagram, phase portraits, first return map, and Fourier spectrum. The resulting bifurcation diagram displays an interesting and complex transition picture with the driving amplitudes as the control parameter.
Thermal stability of epitaxial Fe films on GaN(0001)
Authors: Gao Cunxu , Brandt Oliver , Schönherr Hans-Peter , Jahn Uwe , Herfort Jens , Jenichen Bernd
Published: September 2009

Epitaxial Fe films are grown on GaN(0001) by molecular beam epitaxy at 50 °C. Several samples of one Fe/GaN structure are subjected to rapid thermal annealing from 300 to 950 °C. Using a variety of experimental techniques, we examine the impact of this annealing step upon the morphological, structural, and magnetic properties of these samples. The results demonstrate that the material system Fe/GaN is thermally stable up to a temperature of 700 °C.
Using hierarchies of cause to inform conservation of a naturally rare but critically endangered shrub Lasiopetalum pterocarpum (Malvaceae s.l.)
Authors: Wilkins C. F. , Ladd P. G. , Vincent B. J. , Crawford A. D. , Sage L. W.
Published: September 2009

Understanding the causes of rarity and ways of managing populations of rare species is essential for their successful conservation. The present study applies the conceptual model of a hierarchy of causes to Lasiopetalum pterocarpum E.M.Benn. & K.Shep. (a critically endangered species) to understand better its reproductive and ecological attributes, possible reasons for its rarity and to determine whether this model assists in developing management strategies. L. pterocarpum subpopulations from Serpentine National Park were censused to record abundance, plant health, phenology, flower and fruit production and the presence of any seed bank. These characteristics were matched to criteria in the hierarchies of cause model. There was no evidence of recent seedling recruitment at any subpopulation. Hand-pollination produced a flower-to-fruit conversion proportion similar to that found in the field and self- and cross-pollinations produced virtually the same fruit set. Seed store in soil from beneath the native subpopulations and at a translocation site showed seed was patchily distributed and infrequent. L. pterocarpum is an obligate seeder, killed by fire and dependent on disturbance to break seed dormancy. However, smoke has no effect on germination. Seed production does not constrain population growth, because seedling regeneration after fire in 1999 was prolific at sites where plants had been growing. In the hierarchies of cause framework, the main causes of rarity for this species are taxon ecology, life-history strategy and stochasticity. Thus, concentrating active management on factors related to life history such as mosaic patch burning, fencing after fire to exclude vertebrate grazers, weed control and establishment of translocated populations will aid the preservation of this species in the wild.
Alcohol, Tobacco, and Drug Use among Gay and Bisexual Men
Authors: Ostrow David G. , Stall Ron
Published: September 2009

This chapter details the epidemiology of use and abuse of alcohol, tobacco, and recreational drug use among gay and bisexual men in the United States. The review highlights the history of use and abuse of these drugs over the past quarter century and identifies where there are substantial health disparities regarding use of drugs and where the evidence suggests that gay and bisexual men may not use drugs differently than heterosexual men. The chapter also reviews available programs to address substance abuse issues among gay male communities and areas where the field might best move forward.
Landscape with Two Saints
Authors: Bitel Lisa M.
Published: September 2009

The book is about two unique legendary holy women—Genovefa (Geneviève) of Paris and Brigit of Kildare—who lived in the same historical period religious conversions and barbarian invasions of Romanized northern Europe. They were both famous for traveling widely and sponsoring the building of churches. Why did such seemingly ordinary deeds bring them reputations for sanctity?
Trips 3.0
Authors: Gervais Daniel J
Published: September 2009

This chapter considers the impact of the TRIPS Agreement on development, including how it can and should be measured. It then considers whether the medium- and long-term impact of TRIPS might be to cause or accelerate a geographical displacement in innovation. Finally, it offers some thoughts on the longer-term role of the developing world on the international intellectual property stage.
Rediscovering the Buddha
Authors: Penner Hans H
Published: September 2009

The “Buddhacentric” view of Buddhism continues to shorten the legends of the Buddha into brief outlines. This paradox is based on the mistaken quest for the historical Buddha and the view of myth as irrational or symbolic. This book corrects both mistakes. Part I provides texts from the Buddhist scriptures that demonstrate the mythical/cosmological framework of the legends of the Buddha, that geography is cosmography. Part I presents evidence beginning with the infinity of the Buddhist cosmos, the length of an eon, the origin of humans, episodes concerning Buddha's previous lives, including Vessantara, his birth in our epoch, the birth of his son Rahula, life in the wilderness, enlightenment, performance of miracles, the threat of being murdered, the battles with his cousin, his backaches, conferences with the gods, dinner with a courtesan, the tensions with is family, an upsetting dinner with a blacksmith and much more, ending with his final last days and royal funeral. Part II defines “religion,” “myth”, and “ritual,” and provides a full critique of the quest for the historical Buddha. The book asks: what conclusion can be drawn from this? Mythical texts cannot be translated into historical documents. Part II interprets the legends from within the constraints of the cosmological framework and as episodic “rites of passage.” The Buddha is also restored as the Buddhist Universal Monarch's twin. Their lives are constrained by the same cosmological framework and the liminal stage of their rite of passage is “asceticism.” The final chapter redefines Buddhism as an oppositional relation between householder and renouncer, Buddha and Universal Monarch, mediated by the gift, which produces good merit.
From genome to brainome: charting the lessons learned
Authors: Green Ronald M.
Published: September 2009

This chapter explores converging and diverging issues between genetic and neuroimaging science research and clinical applications. It shows how genetics is intensely communal and familial, while the study of the central nervous system is more focused on the individual. Nonetheless, we learn how the ‘therapeutic gap’ gene hype, and the risk of scientific over-promising from both can lead to advances that may make situations worse before they make them better.
The mind in the movies: a neuroethical analysis of the portrayal of the mind in popular media
Authors: Grainger-Monsen Maren , Karetsky Kim
Published: September 2009

This chapter focuses on one aspect of the media — the film industry — and looks at its effect on the public's perception of how the mind works, both in mental illness and in the neuroscience enhancement technologies that the future holds. It outlines some of the stereotypes of psychiatric illness revealed in popular Hollywood films and highlights the impact that these stereotypes have on both the public and the mentally ill. It examines some of the new independent documentary films addressing mental illness that have been successful in breaking down some of these stereotypes by showing more realistic portrayals of mentally ill patients and families. Finally, it examines how the new frontiers of neuroscience are being portrayed in motion pictures and explore the neuroethical issues that are brought up, as well as questioning the impact that science fiction films have on the public consciousness.
Averroes' Physics
Authors: Glasner Ruth
Published: September 2009

For the first time Averroes' physics is studied on the basis of all available texts and versions of his three commentaries on Aristotle's Physics, including texts that are extant only in Hebrew manuscripts and have not been hitherto studied. A comparison of these sources shows that a diachronic study is absolutely essential. Averroes changed his interpretation of the basic notions of physics—the structure of corporeal reality and the definition of motion—more than once. He has repeatedly rewritten and edited several key chapters in all three commentaries. After many hesitations he offers a bold new interpretation of physics to which this book refers as ‘Aristotelian atomism’. Ideas that are usually ascribed to scholastic scholars and others that were traced back to Averroes but only in a very general form, not only originated with him, but were fully developed by him into a comprehensive and systematic physical system. Unlike earlier Greek or Muslim atomistic systems, Averroes' Aristotelian atomism endeavours to be fully scientific, by Aristotelian standards, and still to provide a basis for an indeterministic natural philosophy. Commonly known as ‘the commentator’ and usually considered to be a faithful follower of Aristotle, Averroes is revealed in his commentaries on the Physics to be an original and sophisticated philosopher.
Trophic amplification of climate warming
Authors: Kirby Richard R. , Beaugrand Gregory
Published: September 2009

Ecosystems can alternate suddenly between contrasting persistent states due to internal processes or external drivers. It is important to understand the mechanisms by which these shifts occur, especially in exploited ecosystems. There have been several abrupt marine ecosystem shifts attributed either to fishing, recent climate change or a combination of these two drivers. We show that temperature has been an important driver of the trophodynamics of the North Sea, a heavily fished marine ecosystem, for nearly 50 years and that a recent pronounced change in temperature established a new ecosystem dynamic regime through a series of internal mechanisms. Using an end-to-end ecosystem approach that included primary producers, primary, secondary and tertiary consumers, and detritivores, we found that temperature modified the relationships among species through nonlinearities in the ecosystem involving ecological thresholds and trophic amplifications. Trophic amplification provides an alternative mechanism to positive feedback to drive an ecosystem towards a new dynamic regime, which in this case favours jellyfish in the plankton and decapods and detritivores in the benthos. Although overfishing is often held responsible for marine ecosystem degeneration, temperature can clearly bring about similar effects. Our results are relevant to ecosystem-based fisheries management (EBFM), seen as the way forward to manage exploited marine ecosystems.
Enhanced T- and B-cell responses to simian immunodeficiency virus (SIV)agm, SIVmac and human immunodeficiency virus type 1 Gag DNA immunization and identification of novel T-cell epitopes in mice via codon optimization
Authors: Siegismund Christine S. , Hohn Oliver , Kurth Reinhard , Norley Stephen
Published: September 2009

As a prelude to primate studies, the immunogenicity of wild-type and codon-optimized versions of simian immunodeficiency virus (SIV)agm Gag DNA, with and without co-administered granulocyte–macrophage colony-stimulating factor (GM-CSF) DNA, was directly compared in two strains of mice. Gag-specific T cells in the splenocytes of BALB/c and C57BL/6 mice immunized by gene gun were quantified by ELISpot using panels of overlapping synthetic peptides (15mers) spanning the entire capsid proteins of SIVagm, SIVmac and human immunodeficiency virus type 1. Specific antibodies were measured by ELISA. Codon optimization was shown to significantly increase the immune response to the DNA immunogens, reducing the amount of DNA necessary to induce cellular and antibody responses by one and two orders of magnitude, respectively. Co-administration of murine GM-CSF DNA was necessary for the induction of high level T- and B-cell responses. Finally, it was possible to identify both known and novel T-cell epitopes in the Gag proteins of the three viruses.
The Grapevine R2R3-MYB Transcription Factor VvMYBF1 Regulates Flavonol Synthesis in Developing Grape Berries
Authors: Czemmel Stefan , Stracke Ralf , Weisshaar Bernd , Cordon Nicole , Harris Nilangani N. , Walker Amanda R. , Robinson Simon P. , Bogs Jochen
Published: September 2009

Flavonols are important ultraviolet light protectants in many plants and contribute substantially to the quality and health-promoting effects of fruits and derived plant products. To study the regulation of flavonol synthesis in fruit, we isolated and characterized the grapevine (Vitis vinifera ‘Shiraz’) R2R3-MYB transcription factor VvMYBF1. Transient reporter assays established VvMYBF1 to be a specific activator of flavonol synthase1 (VvFLS1) and several other promoters of grapevine and Arabidopsis (Arabidopsis thaliana) genes involved in flavonol synthesis. Expression of VvMYBF1 in the Arabidopsis mutant myb12 resulted in complementation of its flavonol-deficient phenotype and confirmed the function of VvMYBF1 as a transcriptional regulator of flavonol synthesis. Transcript analysis of VvMYBF1 throughout grape berry development revealed its expression during flowering and in skins of ripening berries, which correlates with the accumulation of flavonols and expression of VvFLS1. In addition to its developmental regulation, VvMYBF1 expression was light inducible, implicating VvMYBF1 in the control of VvFLS1 transcription. Sequence analysis of VvMYBF1 and VvFLS1 indicated conserved putative light regulatory units in promoters of both genes from different cultivars. By analysis of the VvMYBF1 amino acid sequence, we identified the previously described SG7 domain and an additional sequence motif conserved in several plant MYB factors. The described motifs have been used to identify MYB transcription factors from other plant species putatively involved in the regulation of flavonol biosynthesis. To our knowledge, this is the first functional characterization of a light-inducible MYB transcription factor controlling flavonol synthesis in fruit.
Association between sex steroids and cognition in elderly men
Authors: LeBlanc Erin S. , Wang Patty Y. , Janowsky Jeri S. , Neiss Michelle B. , Fink Howard A. , Yaffe Kristine , Marshall Lynn M. , Lapidus Jodi A. , Stefanick Marcia L. , Orwoll Eric S. ,   for the Osteoporotic Fractures in Men (MrOS) Research Group
Published: September 2009

Objective  To examine the association of cognitive function with sex steroid and sex hormone binding globulin (SHBG) levels among elderly men.

Design  Prospective cohort study, The Osteoporotic Fractures in Men Study (MrOS), consisting of 5995 US community dwelling men of 65 years or older.

Patients  One thousand six hundred and two men were chosen randomly from MrOS cohort for sex steroid level measurements by Mass Spectrometry (MS) at baseline. Two thousand six hundred and twenty‐three MrOS participants with sex steroids measured using RIA were also examined.

Measurements  Baseline and follow‐up (4·5 years later) performance on two cognitive tests: Trails B (executive function and motor speed) and 3MS (global cognitive function). Baseline total testosterone and oestradiol were measured by MS. Free testosterone (free‐T) and free oestradiol (free‐E) were calculated. SHBG was measured by radioimmunoassay. Data were analysed using linear regression.

Results  Baseline free‐T and free‐E levels were not associated with cognitive performance or change in cognition, following adjustment for age, education, race, health status and alcohol use. Baseline SHBG levels were inversely associated with follow‐up trails B (P = 0·03) and 3MS performance (P = 0·02). Higher SHBG was associated with an increased risk of cognitive decline. Total sex steroid levels were not associated with cognitive performance.

Conclusions  Despite large numbers of participants and rigorous sex steroid measurements, we did not observe an association between cognition and either testosterone or oestradiol levels. We conclude that endogenous sex steroids in the normal range are not related to executive function or global cognitive function in elderly men. High SHBG deserves further examination as a risk factor for cognitive decline.
Tolosa–Hunt syndrome: MRI appearances
Authors: Jain R , Sawhney S , Koul RL , Chand P
Published: September 2009

A review of MRI findings in seven patients with Tolosa–Hunt syndrome was carried out. Seven patients presented with unilateral painful ophthalmoplegia. Magnetic resonance imaging studies were carried out to evaluate the cavernous sinuses and orbits. Coronal fast spin‐echo T2‐weighted images and fat‐saturated T1‐weighted coronal and transverse images with and without contrast enhancement were obtained for the cavernous sinuses and orbits. All patients showed focal‐enhancing masses expanding the ipsilateral cavernous sinus. In one patient the mass was extending to the orbital apex and intraorbitally. All patients recovered on corticosteroid therapy and resolution of the masses was documented on follow‐up MRI studies in five patients. One patient had a relapse of symptoms after discontinuing therapy. Magnetic resonance imaging studies of the cavernous sinus and orbital apex show high sensitivity for the detection and follow up of inflammatory mass lesions in Tolosa–Hunt syndrome. Magnetic resonance imaging should be the initial screening study in these patients.
Assessment of a daily online implanted fiducial marker‐guided prostate radiotherapy process
Authors: Greer PB , Dahl K , Ebert MA , White M , Wratten C , Ostwald P , Pichler P , Denham JW
Published: September 2009

The aims of this study were to investigate whether intrafraction prostate motion can affect the accuracy of online prostate positioning using implanted fiducial markers and to determine the effect of prostate rotations on the accuracy of the software‐predicted set‐up correction shifts. Eleven patients were treated with implanted prostate fiducial markers and online set‐up corrections. Orthogonal electronic portal images were acquired to determine couch shifts before treatment. Verification images were also acquired during treatment to assess whether intrafraction motion had occurred. A limitation of the online image registration software is that it does not allow for in‐plane prostate rotations (evident on lateral portal images) when aligning marker positions. The accuracy of couch shifts was assessed by repeating the registration measurements with separate software that incorporates full in‐plane prostate rotations. Additional treatment time required for online positioning was also measured. For the patient group, the overall postalignment systematic prostate errors were less than 1.5 mm (1 standard deviation) in all directions (range 0.2–3.9 mm). The random prostate errors ranged from 0.8 to 3.3 mm (1 standard deviation). One patient exhibited intrafraction prostate motion, resulting in a postalignment prostate set‐up error of more than 10 mm for one fraction. In 14 of 35 fractions, the postalignment prostate set‐up error was greater than 5 mm in the anterior–posterior direction for this patient. Maximum prostate rotations measured from the lateral images varied from 2° to 20° for the patients. The differences between set‐up shifts determined by the online software without in‐plane rotations to align markers, and with rotations applied, was less than 1 mm (root mean square), with a maximum difference of 4.1 mm. Intrafraction prostate motion was found to reduce the effectiveness of the online set‐up for one of the patients. A larger study is required to determine the magnitude of this problem for the patient population. The inability in the current software to incorporate in‐plane prostate rotations is a limitation that should not introduce large errors, provided that the treatment isocentre is positioned near the centre of the prostate.
T‐cell receptor repertoire in IgA nephropathy renal biopsies
Authors: KNIGHT John F , CLARKSON Anthony R , WU Huiling
Published: September 2009

SUMMARY: Renal biopsies from patients with IgA nephropathy (IgAN) were studied to determine whether the presence of αβ and γδ T cells is correlated with disease progression in IgAN. the αβ and γδ T‐cell receptor (TCR) repertoire was further analysed in these renal biopsies. Immunohistochemical staining using mAb (TCRβ and TCRδ) and molecular studies using reverse transcription‐polymerase chain reaction (RT‐PCR) with primers specific for TCR families were undertaken. CDR3 length spectratyping and sequencing of TCR chains were used to analyse the diversity of the CDR3 region of these receptors. It was demonstrated that the presence of γδ T cells is associated with progressive IgAN while αβ T cells are found in both stable and progressive disease. Analysis of the TCR variable (V)β repertoire showed the preferential use of Vβ8 with marked similarities in the CDR3 region by some renal infiltrating T cells in the kidney of some IgAN patients, although T cells infiltrating the renal interstitium of patients with IgAN express heterogeneous T cell receptors. the data from analysis of γδ T‐cell repertoire showed that γδ T cells infiltrating the kidneys of IgAN patients use a restricted subset of γδ T cells with a feature of recurrent junctional amino acid motifs in Vδ1 T cells. the results suggest that both αβ and γδ T cells are involved in the progression of IgAN to renal failure and also that there is clonal expansion of individual αβ or γδ T cells in the kidneys of some IgAN patients. the conserved amino acid in the TCR CDR3 region of Vβ8 and the feature of recurrent junctional amino acid motifs in Vδ1 T cells may indicate antigen‐driven selection.
Reactivity of mesangial cells with aberrantly glycosylated IgA: modulation by angiotensin‐converting enzyme inhibitors
Authors: AMORE Alessandro , CIRINA Paola , CHIESA Monica , COPPO Rosanna
Published: September 2009

SUMMARY: The aim of the present study was to evaluate the modulating effect of angiotensin‐converting enzyme inhibitors (ACE‐I) on the reactivity of mesangial cells (MC) challenged with aberrantly glycosylated IgA. In vitro prepared desialylated and degalactosylated IgA (deSia/deGal IgA) were incubated with cultured MC in the presence or absence of enalapril 10–100ng/mL. DeSia/deGal IgA significantly depressed the MC proliferation rate, simultaneously enhancing the apoptotic rate. A negative control on vascular endothelial growth factor synthesis was found which was mediated by enhanced inducible macrophage‐type nitric oxide synthase activity. the coincubation with enalapril 100ng/mL significantly reversed these effects. Aberrantly glycosylated IgA induced clear expression of α‐smooth muscle cell actin in MC, suggesting an acquisition of miofibroblast‐like phenotype. the ACE‐I, again, significantly inhibited this effect. In order to evaluate the intracellular mechanisms activated by ACE‐I, the authors aimed to investigate the modulating activity of aberrantly glycosylated IgA and ACE‐I on the nuclear factor (NF)‐κB transcriptional factor system. In MC treated with aberrantly glycosylated IgA, the activation of the NF‐κB/IκB complex leading to translocation of NF‐κB into the nucleus, was detected. the phenomenon was significantly blunted by the co‐incubation with ACE‐I. the present study indicates that ACE‐I may limit the effects on MC of the altered glycosylation of circulating IgA molecules in patients with IgA nephropathy via the inhibition of the transcriptional factor NF‐κB. These in vitro results might add further support to the possible benefit of ACE‐I therapy in progressive IgA nephropathy.
Differential expression of platelet‐derived growth factor and transforming growth factor‐β in relation to progression of IgA nephropathy
Authors: KIM Hwal Woong , MOON Kyung Chul , PARK So Yeon , HONG Hye Kyoung , LEE Hyun Soon
Published: September 2009

SUMMARY: The role of platelet‐derived growth factor (PDGF) and transforming growth factor‐β1 (TGF‐β1) in relation to mesangial matrix expansion and progressive glomerulosclerosis in IgA nephropathy (IgAN) is not clearly defined. Expression of PDGF B, TGF‐β1, and extracellular matrix proteins in glomeruli was assessed by immunohistochemistry in 42 biopsies with IgAN and six renal biopsies with no detectable abnormalities. the mRNA expression of PDGF B, TGF‐β1, α1(IV) collagen, laminin B1 and fibronectin genes was further evaluated by in situ hybridization in 25 biopsies with IgAN and six controls. In IgAN, the intensity of immunostaining for PDGF B, type IV collagen, laminin and fibronectin, but not for TGF‐β1, was increased in the mesangium compared with controls. the immunoreactivity of PDGF B was closely correlated with that of type IV collagen and laminin. the number of PDGF B mRNA‐, α1(IV) collagen mRNA‐, laminin B1 mRNA‐, and TGF‐β1 mRNA‐expressing cells/glomerular section, but not the number of fibronectin mRNA‐expressing cells, was increased in IgAN compared with controls. the number of PDGF B mRNA‐expressing cells correlated significantly with the percentage of glomerulosclerosis. In the cellular lesions of focal segmental glomerulosclerosis (FSGS), expression of TGF‐β1 protein and mRNA was markedly increased in visceral glomerular epithelial cells (GEC). These results suggest that PDGF B mainly overproduced by mesangial cells may cause mesangial matrix expansion, whereas TGF‐β1 produced by GEC may be related to the formation of FSGS in IgAN. Thus, PDGF B and TGF‐β1 may play differential roles in the pathogenesis of renal fibrosis and the progression of IgAN.
Treatment of IgA nephropathy in children
Authors: YOSHIKAWA Norishige
Published: September 2009

SUMMARY: IgA nephropathy is the most common primary glomerulonephritis in the world, and about 20–50% of patients develop progressive renal failure. the pathogenesis is still unknown and treatment has not yet been established. Knowledge concerning childhood IgA nephropathy has expanded greatly in the last 10 years, and its importance as the major form of glomerulonephritis and major contributor to end‐stage renal disease is also becoming apparent in children. This communication focuses on the treatment of IgA nephropathy in children.
ENDOSCOPIC DEFINITION OF ESOPHAGOGASTRIC JUNCTION FOR DIAGNOSIS OF BARRETT'S ESOPHAGUS: IMPORTANCE OF SYSTEMATIC EDUCATION AND TRAINING
Authors: Ishimura Norihisa , Amano Yuji , Kinoshita Yoshikazu
Published: September 2009

The diagnosis of Barrett's esophagus (BE) requires an accurate recognition of the columnar‐lined esophagus at endoscopy. However, a universally accepted standardized endoscopic grading system of BE was lacking prior to the development of the Prague ‘circumferential and maximal’ criteria. In this system, the landmark for the esophagogastric junction (EGJ) is the proximal end of the gastric folds, not the distal end of the palisade vessels, which are used to endoscopically identify the EGJ in Japan. Although the circumferential and maximal criteria are clinically relevant, an important shortcoming of this system may be failure to identify short‐segment BE, a lesion that is found frequently in the Japanese. To compare the diagnostic yield for BE when using the palisade vessels versus gastric folds as a landmark for the EGJ, we evaluated interobserver diagnostic concordance. The endoscopic identification of the EGJ using both landmarks resulted in unacceptably low kappa coefficients of reliability. However, there was a statistically significant improvement after the participants were thoroughly trained in identification of the EGJ during the endoscopic study. Although it remains controversial which landmark is better for the endoscopic diagnosis of BE, it is important to systematically educate and train endoscopists in order to improve diagnostic consistency in patients with BE.