bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel stepwise analysis procedure of genome‐wide expression profiles identifies transcript signatures of thiamine genes as classifiers of mitochondrial mutants
Authors: Eijssen L. M. T. , Lindsey P. J. , Peeters R. , Westra R. L. , van Eijsden R. G. E. , Bolotin‐Fukuhara M. , Smeets H. J. M. , Vlietinck R. F. M.
Published: December 2007

To extract functional information on genes and processes from large expression datasets, analysis methods are required that can computationally deal with these amounts of data, are tunable to specific research questions, and construct classifiers that are not overspecific to the dataset at hand. To satisfy these requirements, a stepwise procedure that combines elements from principal component analysis and discriminant analysis, was developed to specifically retrieve genes involved in processes of interest and classify samples based upon those genes. In a global expression dataset of 300 gene knock‐outs in Saccharomyces cerevisiae, the procedure successfully classified samples with similar ‘cellular component’ Gene Ontology annotations of the knock‐out gene by expression signatures of limited numbers of genes. The genes discriminating ‘mitochondrion’ from the other subgroups were evaluated in more detail. The thiamine pathway turned out to be one of the processes involved and was successfully evaluated in a logistic model to predict whether yeast knock‐outs were mitochondrial or not. Further, this pathway is biologically related to the mitochondrial system. Hence, this strongly indicates that our approach is effective and efficient in extracting meaningful information from large microarray experiments and assigning functions to yet uncharacterized genes. Copyright © 2007 John Wiley & Sons, Ltd.
Comparison of the Frying Stability of Standard Palm Olein and Special Quality Palm Olein
Authors: Ahmad Tarmizi Azmil Haizam , Ismail Razali
Published: December 2007

The main goal of this work was to investigate the stability of standard palm olein (SPOo) and special quality palm olein (SQPOo) under continuous frying conditions. The rate of free fatty acid (FFA) formation was slightly higher for SPOo than SQPOo during 56 h of frying. An equilibrium state was reached at around 40 h for SPOo and 32 h for SQPOo, whereby FFA varied within a narrow range of 0.30–0.32 and 0.22–0.25%, respectively. Smoke point of SPOo and SQPOo progressively dropped from 212 to 184 °C and from 227 to 191 °C. Tocols of SPOo and SQPOo declined from 550 to 273 mg kg−1 and from 720 to 447 mg kg−1 after 56 h of frying, respectively. Oxidative stability of both oils decreased after the successive frying. Induction time of SPOo dropped from 22.3 to 14.9 h while SQPOo decreased from 25.5 to 18.3 h. Polar and polymer compounds increased as frying progressed. The SPOo had higher levels of polar compounds, averaging 11.8%, compared to the 10.2% in SQPOo. However, SPOo had lower levels of polymer compounds compared to SQPOo, averaging 2.1 and 2.5%, respectively. Hence, this work confirms that frying performance using SPOo was comparable to SQPOo for use in industrial production of snack foods (potato chips).
Précis ofEvolution in Four Dimensions
Authors: Jablonka Eva , Lamb Marion J.
Published: December 2007

In his theory of evolution, Darwin recognized that the conditions of life play a role in the generation of hereditary variations, as well as in their selection. However, as evolutionary theory was developed further, heredity became identified with genetics, and variation was seen in terms of combinations of randomly generated gene mutations. We argue that this view is now changing, because it is clear that a notion of hereditary variation that is based solely on randomly varying genes that are unaffected by developmental conditions is an inadequate basis for evolutionary theories. Such a view not only fails to provide satisfying explanations of many evolutionary phenomena, it also makes assumptions that are not consistent with the data that are emerging from disciplines ranging from molecular biology to cultural studies. These data show that the genome is far more responsive to the environment than previously thought, and that not all transmissible variation is underlain by genetic differences. InEvolution in Four Dimensions(2005) we identify four types of inheritance (genetic, epigenetic, behavioral, and symbol-based), each of which can provide variations on which natural selection will act. Some of these variations arise in response to developmental conditions, so there are Lamarckian aspects to evolution. We argue that a better insight into evolutionary processes will result from recognizing that transmitted variations that are not based on DNA differences have played a role. This is particularly true for understanding the evolution of human behavior, where all four dimensions of heredity have been important.
Only three dimensions and the mother of invention
Authors: Foss Jeff
Published: December 2007

Although the first three dimensions of evolution outlined by Jablonka & Lamb (J&L) are persuasively presented as aspects of evolutionary science, the fourth dimension, symbolic evolution, is problematic: Though it may in some metaphorical sense be happening, there cannot be a science of symbolic evolution. Symbolic evolution essentially involves meaning, which, besides being nonphysical, resolutely resists scientific categorization.
Extended evolutionary theory makes human culture more amenable to evolutionary analysis
Authors: Mesoudi Alex
Published: December 2007

Jablonka & Lamb's (J&L's) extended evolutionary theory is more amenable to being applied to human cultural change than standard neo-Darwinian evolutionary theory. However, the authors are too quick to dismiss past evolutionary approaches to human culture. They also overlook a potential parallel between evolved genetic mechanisms that enhance evolvability and learned cognitive mechanisms that enhance learnability.
Signs of culture
Authors: Gardner R. Allen
Published: December 2007

Ramsey et al. present an ingenious method to study behavioral novelty under field conditions within relatively narrow time constraints. This evokes discussion of lateral spread of innovation from individual to individual versus vertical spread from generation to generation. This discussion of incipient culture helps to place the traditional biological tool of cross-fostering into philosophical and anthropological context.
Animal innovation and rationality: Distinguishing productivity from efficiency
Authors: Khalil Elias L.
Published: December 2007

For the authors of the target article, innovations are underdetermined by environmental inducement – but are still adopted in the future. For a productive technology to be adopted, the technology must also be efficient. To be efficient, it must be determined by constraints or environmental inducements. However, this contradicts the authors' notion of “underdetermination.” To make matters clear, we need to distinguish between two kinds of determination: the “source” of the innovation as opposed to “inducement” that makes the organism adopt it in the future.
Is all learning innovation?
Authors: Rendell Luke , Hoppitt William , Kendal Jeremy
Published: December 2007

Research on animal innovation is an underdeveloped field, and for this reason we welcome the efforts Ramsey and colleagues have made to stimulate its study in wild populations. However, we feel that in attempting to find an operational definition the authors have overstretched the idea of what we should consider innovation in some areas and over-restricted it in others.
The animal variations: When mechanisms matter in accounting for function
Authors: Viciana Hugo , Claidiere Nicolas
Published: December 2007

We contend that Ramsey et al.'s definition of animal innovationsensuprocess may be partially misleading when investigating mechanisms underlying animal innovation. By excluding social learning from the “process” of innovation, they may be reproducing a dichotomous schema that does not accurately correspond to our knowledge of the acquisition of novel behavioral variants. This gives us some reason to doubt the functional specification of the defined process of innovation.
State Recognition: Admission (Im)Possible
Authors: BUYSE ANTOINE , LAWSON RICK
Published: December 2007

This article focuses on state recognition in the European context and on the admission of states to the Council of Europe after the end of the Cold War. It argues that two global trends identified by John Dugard in the 1980s have continued since then: a common approach to state recognition has been adopted and the criteria for state recognition have increasingly been given normative content. This reflects that the constitutive theory of state recognition continued to be popular. The two trends have not automatically resulted in a more legal approach to the issues, as the case study of Bosnia and Herzegovina illustrates.
Professor Dugard as an Innovator in the Work of the International Law Commission
Authors: ESCARAMEIA PAULA
Published: December 2007

This article is a personal account of the work of Professor Dugard at the International Law Commission from the point of view of someone who sits next to him in the Commission and has worked with him there for the past six years. It tries to show how his proposals and arguments, especially concerning the topic ‘Diplomatic Protection’, for which he was the Special Rapporteur, greatly directed the debate and led to the approval of innovatory articles such as those concerning refugees, stateless persons, and members of ships' crews and recommendations to governments to take the interests of people injured more seriously. Above all, it tries to show how international law-making processes can be influenced by the determination, the knowledge, and the intelligence of a person whose dedication to the defence of human rights and a fairer world order has been exemplary.
Delirium – a clinical overview
Authors: White Susan , Bayer Antony
Published: December 2007

Delirium is a disorder characterized by a fluctuating disturbance of consciousness and attention, with changes in cognition or perception, which develops over a short period of time and is attributable to an underlying physical cause. It is often accompanied by disturbance of the sleep-wake cycle and altered psychomotor behaviour.
An efficient rounding‐off rule estimator: Application to daily rainfall time series
Authors: Deidda Roberto
Published: December 2007

An overview of problems and errors arising when fitting parametric distributions and applying goodness of fit tests on samples containing roughly rounded off measurements is first illustrated. The paper then presents the rounding‐off rule estimator (RRE), an original method that allows the estimation of the percentages of rainfall measurements that have been rounded at some potential resolutions. The efficiency of the RRE is evaluated using a wide set of samples drawn by different distributions and rounded off according to different rounding rules. Finally, the RRE is applied on 340 daily rainfall time series collected by the rain gauge network of the Sardinian Hydrological Survey (Italy). In most stations, results revealed the presence of significant percentages of roughly rounded‐off measurements, even at 1 and 5 mm resolutions, rather than at the standard 0.1 or 0.2 mm discretization. The application of the proposed RRE may give important support to perform quality data analyses, to assess and discriminate methods to fit parametric distributions on rounded‐off samples, and to detect if and how the precision of recorded measurements might have changed in long time series used for climatic change studies.
Thermo‐mechanical adjustment after impacts during planetary growth
Authors: Monteux Julien , Coltice Nicolas , Dubuffet Fabien , Ricard Yanick
Published: December 2007

The thermal evolution of planets during their growth is strongly influenced by impact heating. The temperature increase after a collision is mostly located next to the shock. For Moon to Mars size planets where impact melting is limited, the long term thermo‐mechanical readjustment is driven by spreading and cooling of the heated zone. To determine the time and length scales of the adjustment, we developed a numerical model in axisymmetric cylindrical geometry with variable viscosity. We show that if the impactor is larger than a critical size, the spherical heated zone isothermally flattens until its thickness reaches a value for which motionless thermal diffusion becomes more effective. The thickness at the end of advection depends only on the physical properties of the impacted body. The obtained timescales for the adjustment are comparable to the duration of planetary accretion and depend mostly on the physical properties of the impacted body.
Estimation of the total electron content of the Martian ionosphere using radar sounder surface echoes
Authors: Safaeinili Ali , Kofman Wlodek , Mouginot Jérémie , Gim Yonggyu , Herique Alain , Ivanov Anton B. , Plaut Jeffrey J. , Picardi Giovanni
Published: December 2007

The Martian ionosphere's local total electron content (TEC) and the neutral atmosphere scale height can be derived from radar echoes reflected from the surface of the planet. We report the global distribution of the TEC by analyzing more than 750,000 echoes of the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS). This is the first direct measurement of the TEC of the Martian ionosphere. The technique used in this paper is a novel “transmission‐mode” sounding of the ionosphere of Mars in contrast to the Active Ionospheric Sounding experiment (AIS) on MARSIS, which generally operates in the reflection mode. This technique yields a global map of the TEC for the Martian ionosphere. The radar transmits a wideband chirp signal that travels through the ionosphere before and after being reflected from the surface. The received waves are attenuated, delayed and dispersed, depending on the electron density in the column directly below the spacecraft. In the process of correcting the radar signal, we are able to estimate the TEC and its global distribution with an unprecedented resolution of about 0.1 deg in latitude (∼5 km footprint). The mapping of the relative geographical variations in the estimated nightside TEC data reveals an intricate web of high electron density regions that correspond to regions where crustal magnetic field lines are connected to the solar wind. Our data demonstrates that these regions are generally but not exclusively associated with areas that have magnetic field lines perpendicular to the surface of Mars. As a result, the global TEC map provides a high‐resolution view of where the Martian crustal magnetic field is connected to the solar wind. We also provide an estimate of the neutral atmospheric scale height near the ionospheric peak and observe temporal fluctuations in peak electron density related to solar activity.
Melt season duration and ice layer formation on the Greenland ice sheet, 2000–2004
Authors: Wang Libo , Sharp Martin , Rivard Benoit , Steffen Konrad
Published: December 2007

Time series of enhanced resolution QuikSCAT images were used to map the extent and duration of surface melt and the distribution of ice layer formation on the Greenland ice sheet in the period 2000–2004. Apart from the bare ice and the mixed pixels (10%) along the ice sheet margin where melt cannot be determined reliably, annual melt duration and melt anomaly maps were produced across the ice sheet (90%) for each summer. Over the 5‐year period, the mean melt duration for the ice sheet ranged from 14.3 to 20.5 d. The proportion of the ice sheet that experienced melting in a given year ranged from 44.2% to 79.2%. Extensive melt in 2002 was caused by a single melt event of a few days duration. This event was associated with the intrusion of a ridge of high pressure from the North Atlantic Ocean that brought warm air onto the ice sheet. The change in biweekly averaged backscatter between the freeze up periods in the current and previous falls was used to identify changes in the distribution of ice layers in snow between successive melt seasons. The year 2002 had the maximum melt extent and duration, and ice layer formation extended to higher elevations than in other years. Interannual changes in the distribution of ice layer formation may be associated with changes in surface height that are not necessarily indicative of mass balance changes. Mapping of ice layer formation is thus potentially useful for interpreting both real and apparent height changes measured by altimetry.
Eastern tropical Pacific hydrologic changes during the past 27,000 years from D/H ratios in alkenones
Authors: Pahnke Katharina , Sachs Julian P. , Keigwin Lloyd , Timmermann Axel , Xie Shang‐Ping
Published: December 2007

The tropical Pacific plays a central role in the climate system by providing large diabatic heating that drives the global atmospheric circulation. Quantifying the role of the tropics in late Pleistocene climate change has been hampered by the paucity of paleoclimate records from this region and the lack of realistic transient climate model simulations covering this period. Here we present records of hydrogen isotope ratios (δD) of alkenones from the Panama Basin off the Colombian coast that document hydrologic changes in equatorial South America and the eastern tropical Pacific over the past 27,000 years (a) and the past 3 centuries in detail. Comparison of alkenone δD values with instrumental records of precipitation over the past ∼100 a suggests that δD can be used as a hydrologic proxy. On long timescales our records indicate reduced rainfall during the last glacial period that can be explained by a southward shift of the mean position of the Intertropical Convergence Zone and an associated reduction of Pacific moisture transport into Colombia. Precipitation increases at ∼17 ka in concert with sea surface temperature (SST) cooling in the North Atlantic and the eastern tropical Pacific. A regional coupled model, forced by negative SST anomalies in the Caribbean, simulates an intensification of northeasterly trade winds across Central America, increased evaporative cooling, and a band of increased rainfall in the northeastern tropical Pacific. These results are consistent with the alkenone SST and δD reconstructions that suggest increasing precipitation and SST cooling at the time of Heinrich event 1.
Do Certain Readings of Freud Constitute “Pathological Science”? A Comment on Boag (2006)
Authors: McNally Richard J.
Published: December 2007

Boag (2006) holds that many psychologists misinterpret Freud's concept of repression as chiefly concerning motivated forgetting of trauma. He characterizes the persistence of this alleged error as an instance of “pathological science” whereby the field's self-correcting mechanisms fail to function properly. The purpose of this comment is to provide an alternative, nonpathological account situated within the context of the recovered memory debate.
A theoretical study of the low-lying excited electronic states of thiocarbonyl chlorofluoride and their dissociation pathways
Authors: Lee Kunhye , Baeck Kyoung Koo
Published: December 2007

The spectroscopic constants for the ground (X̃A11) and low-lying triplet and singlet excited states (ãA″3,ÃA″1,B̃A′1) of thiocarbonyl chlorofluoride (ClFCS) were obtained using the equation-of-motion coupled-cluster singles and doubles method. The calculated vibrational frequencies of the electronic states were within 4% of the experimental values for 21 of the frequencies, but four calculated frequencies were 20%–40% away from the corresponding experimentally reported values, suggesting the need to reexamine previous experimental spectra. The spectroscopic properties of the radical fragments (FCS, ClCS, and CClF) were also studied, and the correlation diagram between the excited electronic states of ClFCS and possible combinations of dissociation fragments were obtained. The potential energy surfaces (PESs) of the excited electronic states of ClFCS along possible dissociation pathways were also studied. The main qualitative dynamical features of the S1(ÃA″1)←S2(B̃A′1) fluorescence of ClFCS, which may occur in spite of the small barrier (8kcal∕mol) on the S2 PES to the dissociation of C–Cl bond, are discussed.
From nucleation to growth of catalyst-free GaN nanowires on thin AlN buffer layer
Authors: Songmuang R. , Landré O. , Daudin B.
Published: December 2007

We demonstrate that thin AlN buffer layers improve the orientation of GaN nanowire grown on Si(111). The deposited GaN initially forms into islands which act as a seed for the wires. By raising substrate temperature, the actual amount of grown material decreases but wire density increases and well-separated wires are achieved. Fast wire length growth rate at high growth temperature is assigned to an enhancement of adatom diffusion. The upper limit of length growth rate is determined by the supply rate of active nitrogen.
Blending of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) with poly(ethyleneimine) as an active layer in depletion-mode organic thin film transistors
Authors: Lin Yu-Ju , Li Yu-Chang , Yeh Hong-Jian , Wang Yeong-Her , Wen Ten-Chin , Huang Li-Ming , Chen Ying-Kuo
Published: December 2007

The conjugated polymer poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT-PSS) is usually applied in fabricating electrodes of devices. In this work, the applications to organic a thin film transistor with the introduction of poly(ethyleneimine) (PEI) into the PEDOT-PSS are investigated. The conductivity of PEDOT-PSS can be reduced by incorporating PEI into PEDOT-PSS, which can be applied as an active layer instead of electrodes for devices application. Based on the PEDOT-PSS blended with PEI, the fabricated devices posses a depletion-mode transistor behavior with the on/off ratio of about 103 is used. Meanwhile, the role of PEI in PEDOT-PSS to modulate the channel conductivity is discussed.
Hot phonon effect on electron velocity saturation in GaN: A second look
Authors: Khurgin Jacob , Ding Yujie J. , Jena Debdeep
Published: December 2007

A theoretical model is developed for electron velocity saturation in high power GaN transistors. It is shown that electron velocity at high electric fields is reduced due to heating of electron gas since the high density of nonequilibrium LO phonons cannot efficiently transfer heat to the lattice. However, the resulting degradation of electron velocity is found to be weaker than previously reported. The results are compared with experimental data, and the ways to improve the efficiency of cooling the electron gas to increase the drift velocity are discussed.
Ferroelectric parallel-plate capacitors with copper electrodes for high-frequency applications
Authors: Riekkinen Tommi , Mattila Tomi , van Dijken Sebastiaan , Lüker A. , Zhang Qi , Kirby Paul B. , Sánchez Ana M.
Published: December 2007

Tunable capacitors with a Cu∕PbxSr1−xTiO3∕Cu parallel-plate structure have been fabricated using a layer transfer method. The use of a Cu bottom electrode results in a giant electrode Q-factor×capacitor area product of QelecA=3.79×105μm2 at 1GHz. The dielectric constant at room temperature is 420 and the tunability amounts to 73% near a breakdown voltage of 35V. The major advantages of the layer transfer method include low electrode losses, the freedom to select an auxiliary substrate and seed layer for ferroelectric film growth irrespective of their high-frequency properties, and the possibility to utilize a large variety of device substrates as they no longer act as template for film growth.
Mapping of adult plant resistance to net form of net blotch in three Australian barley populations
Authors: Lehmensiek A. , Platz G. J. , Mace E. , Poulsen D. , Sutherland M. W.
Published: December 2007

Net form of net blotch (NFNB), caused by Pyrenophora teres Drechs. f. teres Smedeg., is a serious disease problem for the barley industry in Australia and other parts of the world. Three doubled haploid barley populations, Alexis/Sloop, WI2875-1/Alexis, and Arapiles/Franklin, were used to identify genes conferring adult plant resistance to NFNB in field trials. Quantitative trait loci (QTLs) identified were specific for adult plant resistance because seedlings of the parental lines were susceptible to the NFNB isolates used in this study. QTLs were identified on chromosomes 2H, 3H, 4H, and 7H in both the Alexis/Sloop and WI2875-1/Alexis populations and on chromosomes 1H, 2H, and 7H in the Arapiles/Franklin population. Using QTLNetwork, epistatic interactions were identified between loci on chromosomes 3H and 6H in the Alexis/Sloop population, between 2H and 4H in the WI2875-1/Alexis population, and between 5H and 7H in the Arapiles/Franklin population. Comparisons with earlier studies of NFNB resistance indicate the pathotype-dependent nature of many resistance QTLs and the importance of establishing an international system of pathotype nomenclature and differential testing.
Observation and Analysis of RW Doradus
Authors: Marino B. F. , Walker W. S. G. , Bembrick C. , Budding E.
Published: December 2007

Photometry of the short-period (P ∼0.285 d) low-mass (M1 ∼0.67, M2 ∼0.48 M⊙) W UMa-type eclipsing binary RW Dor, mainly involving a good series of observations in 1987–88, using standard B and V filters at the Auckland Observatory, is examined. Analysis via light curve fittings alone permits both transit (near main sequence) and occultation (W-type contact binary) solutions. Consideration of proximity or other effects on the relatively small number of measured radial velocities gives rise to a more detailed review of the alternatives, though the (W-type) configuration determined by Hilditch, Hill & Bell (1992) is still confirmed. Further implications of this configuration are examined, given an apparent general trend to period decrease (Δ P/P ∼6 × 10−11), and some light curve asymmetry. This is consistent with the initially low-mass companion, Case-B scenario of Budding (1984). The evidence does suggest irregularity of the period variation however, and further detailed surveillance, including more spectroscopy, is desirable.
Science with the Australian Square Kilometre Array Pathfinder
Authors: Johnston S. , Bailes M. , Bartel N. , Baugh C. , Bietenholz M. , Blake C. , Braun R. , Brown J. , Chatterjee S. , Darling J. , Deller A. , Dodson R. , Edwards P. G. , Ekers R. , Ellingsen S. , Feain I. , Gaensler B. M. , Haverkorn M. , Hobbs G. , Hopkins A. , Jackson C. , James C. , Joncas G. , Kaspi V. , Kilborn V. , Koribalski B. , Kothes R. , Landecker T. L. , Lenc E. , Lovell J. , Macquart J.-P. , Manchester R. , Matthews D. , McClure-Griffiths N. M. , Norris R. , Pen U.-L. , Phillips C. , Power C. , Protheroe R. , Sadler E. , Schmidt B. , Stairs I. , Staveley-Smith L. , Stil J. , Taylor R. , Tingay S. , Tzioumis A. , Walker M. , Wall J. , Wolleben M.
Published: December 2007

The future of centimetre and metre-wave astronomy lies with the Square Kilometre Array (SKA), a telescope under development by a consortium of 17 countries that will be 50 times more sensitive than any existing radio facility. Most of the key science for the SKA will be addressed through large-area imaging of the Universe at frequencies from a few hundred MHz to a few GHz. The Australian SKA Pathfinder (ASKAP) is a technology demonstrator aimed in the mid-frequency range, and achieves instantaneous wide-area imaging through the development and deployment of phased-array feed systems on parabolic reflectors. The large field-of-view makes ASKAP an unprecedented synoptic telescope that will make substantial advances in SKA key science. ASKAP will be located at the Murchison Radio Observatory in inland Western Australia, one of the most radio-quiet locations on the Earth and one of two sites selected by the international community as a potential location for the SKA. In this paper, we outline an ambitious science program for ASKAP, examining key science such as understanding the evolution, formation and population of galaxies including our own, understanding the magnetic Universe, revealing the transient radio sky and searching for gravitational waves.
Dimeric PKD regulates membrane fission to form transport carriers at the TGN
Authors: Bossard Carine , Bresson Damien , Polishchuk Roman S. , Malhotra Vivek
Published: December 2007

Protein kinase D (PKD) is recruited to the trans-Golgi network (TGN) through interaction with diacylglycerol (DAG) and is required for the biogenesis of TGN to cell surface transport carriers. We now provide definitive evidence that PKD has a function in membrane fission. PKD depletion by siRNA inhibits trafficking from the TGN, whereas expression of a constitutively active PKD converts TGN into small vesicles. These findings demonstrate that PKD regulates membrane fission and this activity is used to control the size of transport carriers, and to prevent uncontrolled vesiculation of TGN during protein transport.
Myofibroblast contraction activates latent TGF-β1 from the extracellular matrix
Authors: Wipff Pierre-Jean , Rifkin Daniel B. , Meister Jean-Jacques , Hinz Boris
Published: December 2007

The conjunctive presence of mechanical stress and active transforming growth factor β1 (TGF-β1) is essential to convert fibroblasts into contractile myofibroblasts, which cause tissue contractures in fibrotic diseases. Using cultured myofibroblasts and conditions that permit tension modulation on the extracellular matrix (ECM), we establish that myofibroblast contraction functions as a mechanism to directly activate TGF-β1 from self-generated stores in the ECM. Contraction of myofibroblasts and myofibroblast cytoskeletons prepared with Triton X-100 releases active TGF-β1 from the ECM. This process is inhibited either by antagonizing integrins or reducing ECM compliance and is independent from protease activity. Stretching myofibroblast-derived ECM in the presence of mechanically apposing stress fibers immediately activates latent TGF-β1. In myofibroblast-populated wounds, activation of the downstream targets of TGF-β1 signaling Smad2/3 is higher in stressed compared to relaxed tissues despite similar levels of total TGF-β1 and its receptor. We propose activation of TGF-β1 via integrin-mediated myofibroblast contraction as a potential checkpoint in the progression of fibrosis, restricting autocrine generation of myofibroblasts to a stiffened ECM.
Drosophila TIF-IA is required for ribosome synthesis and cell growth and is regulated by the TOR pathway
Authors: Grewal Savraj S. , Evans Justin R. , Edgar Bruce A.
Published: December 2007

Synthesis of ribosomal RNA (rRNA) is a key step in ribosome biogenesis and is essential for cell growth. Few studies, however, have investigated rRNA synthesis regulation in vivo in multicellular organisms. Here, we present a genetic analysis of transcription initiation factor IA (TIF-IA), a conserved RNA polymerase I transcription factor. Drosophila melanogaster Tif-IA−/− mutants have reduced levels of rRNA synthesis and sustain a developmental arrest caused by a block in cellular growth. We find that the target of rapamycin (TOR) pathway regulates TIF-IA recruitment to rDNA. Furthermore, we show that the TOR pathway regulates rRNA synthesis in vivo and that TIF-IA overexpression can maintain rRNA transcription when TOR activity is reduced in developing larvae. We propose that TIF-IA acts in vivo as a downstream growth–regulatory target of the TOR pathway. Overexpression of TIF-IA also elevates levels of both 5S RNA and messenger RNAs encoding ribosomal proteins. Stimulation of rRNA synthesis by TIF-IA may therefore provide a feed-forward mechanism to coregulate the levels of other ribosome components.
Perirhinal cortex resolves feature ambiguity in configural object recognition and perceptual oddity tasks
Authors: Bartko Susan J. , Winters Boyer D. , Cowell Rosemary A. , Saksida Lisa M. , Bussey Timothy J.
Published: December 2007

The perirhinal cortex (PRh) has a well-established role in object recognition memory. More recent studies suggest that PRh is also important for two-choice visual discrimination tasks. Specifically, it has been suggested that PRh contains conjunctive representations that help resolve feature ambiguity, which occurs when a task cannot easily be solved on the basis of features alone. However, no study has examined whether the ability of PRh to resolve configural feature ambiguity is related to its role in object recognition. Therefore, we examined whether bilateral excitotoxic lesions of PRh or PPRh (perirhinal plus post-rhinal cortices) in the rat would cause deficits in a configural spontaneous object recognition task, and a configural simultaneous oddity discrimination task, in which the task could not be solved on the basis of features, but could only be solved using conjunctive representations. As predicted by simulations using a computational model, rats with PPRh lesions were impaired during a minimal-delay configural object recognition task. These same rats were impaired during a zero-delay configural object recognition task. Furthermore, rats with localized PRh lesions were impaired in a configural simultaneous oddity discrimination task. These findings support the idea that PRh contains conjunctive representations for the resolution of feature ambiguity and that these representations underlie a dual role for PRh in memory and perception.
A Periodic-Transient Method for High-Resolution Heat Transfer Measurement on Two-Dimensional Curved Surfaces
Authors: Röger M.
Published: December 2007

Measurement of heat transfer distribution is frequently required in engineering. However, some heat transfer techniques are not able to measure accurately on two-dimensional curved surfaces. In this field, periodic-transient measurement methods are advantageous. This paper describes the development of a periodic-transient technique for high-resolution heat transfer measurement and its application to multiple air-jet cooling of a concave solar receiver window. In contrast to other measurement techniques, the periodic-transient technique requires neither homogenous heating nor quantitative measurement of surface or fluid temperatures. The heat transfer coefficient is determined by periodically heating the substrate and evaluating the phase shift between the heat flux penetrating the substrate and the resulting temperature response. Equations for a hollow-sphere and flat-plate substrates are derived. The curved window surface is periodically heated by a simple device with standard light bulbs. A procedure for taking the transient heating characteristic into consideration is described. The distribution of surface temperature fluctuation is measured nonintrusively by thermography. For the sample application of air-jet cooling, a detailed uncertainty estimation is presented. The relative measurement uncertainty of the local, convective heat transfer coefficient ranges from −2.4% to +14.1% for h=10W∕(m2K) and from −2.3% to +9.7% for h=200W∕(m2K). The uncertainty of the spatially averaged heat transfer coefficient lies between +2.0% and +9.8% for hm=10W∕(m2K) and between +0.7% and +6.7% for hm=200W∕(m2K). The periodic-transient method described complements established techniques for high-resolution heat transfer measurements on two-dimensional curved surfaces.
Mass (Heat) Transfer Downstream of Blockages With Round and Elongated Holes in a Rectangular Channel
Authors: Ahn H. S. , Lee S. W. , Lau S. C. , Banerjee D.
Published: December 2007

Turbulent forced convective mass (heat) transfer downstream of blockages with round and elongated holes in a rectangular channel was studied. The blockages and the channel had the same 12:1 (width-to-height ratio) cross section, and a distance equal to twice the channel height separated consecutive blockages. The diameter of the holes was either 0.5 or 0.75 of the height of the channel. Naphthalene sublimation experiments were conducted with four hole aspect ratios (hole-width-to-height ratios) between 1.0 and 3.4, two hole-to-channel area ratios (ratios of total hole cross-sectional area to channel cross-sectional area) of 0.2 and 0.3, and Reynolds numbers (based on the channel hydraulic diameter) of 7000 and 17,000. The effects of the hole aspect ratio, for each hole-to-channel area ratio, on the average mass (heat) transfer and the local mass (heat) transfer distribution on the exposed primary channel wall between consecutive blockages were examined. The results of the study showed that the blockages with holes caused the average mass (heat) transfer to be as high as about eight times that for fully developed turbulent flow through a smooth channel at the same mass flow rate. The elongated holes caused higher overall mass (heat) transfer and larger spanwise variation of the local mass (heat) transfer on the channel wall than round holes.
Assessment of a Second-Moment Closure Model for Strongly Heated Internal Gas Flows
Authors: Spall Robert E. , Nisipeanu Eugen , Richards Adam
Published: December 2007

Both low- and high-Reynolds-number versions of the stress-ω model of Wilcox (Turbulence Modeling for CFD, 2nd ed., DCW Industries, Inc.) were used to predict velocity and heat transfer data in a high-heat-flux cylindrical tube for which fluid properties varied strongly with temperature. The results indicate that for accurate heat transfer calculations under the conditions considered in this study, inclusion of low-Reynolds-number viscous corrections to the model are essential. The failure of the high-Reynolds-number model to accurately predict the wall temperature was attributed to an overprediction of the near-wall velocity.
Flow and Heat Transfer Characteristics in Rectangular Channels With Staggered Transverse Ribs on Two Opposite Walls
Authors: Fung Huang Rong , Woei Chang Shyy , Chen Kun-Hung
Published: December 2007

The flow characteristics and the heat transfer properties of the rectangular channels with staggered transverse ribs on two opposite walls are experimentally studied. The rib height to channel height ratio ranges from 0.15 to 0.61 (rib height to channel hydraulic diameter ratio from 0.09 to 0.38). The pitch to rib height ratio covers from 2.5 to 26. The aspect ratio of the rectangular channel is 4. The flow characteristics are studied in a water channel, while the heat transfer experiments are performed in a wind tunnel. Particle image velocimetry (PIV) is employed to obtain the quantitative flow field characteristics. Fine-wire thermocouples imbedded near the inner surface of the bottom channel wall are used to measure the temperature distributions of the wall and to calculate the local and average Nusselt numbers. Using the PIV measured streamline patterns, various characteristic flow modes, thru flow, oscillating flow, and cell flow, are identified in different regimes of the domain of the rib height to channel height ratio and pitch to rib height ratio. The vorticity, turbulence intensity, and wall shear stress of the cell flow are found to be particularly larger than those of other characteristic flow modes. The measured local and average Nusselt numbers of the cell flow are also particularly higher than those of other characteristic flow modes. The distinctive flow properties are responsible for the drastic increase of the heat transfer due to the enhancement of the momentum, heat, and mass exchanges within the flow field induced by the large values of the vorticity and turbulence intensity. Although the thru flow mode is conventionally used in the ribbed channel for industrial application, the cell flow could become the choice if the heat transfer rate, instead of the pressure loss, is the primary concern.
Fully Developed Couette Flow of Three Fluids With Variable Thermophysical Properties Flowing Through a Porous Medium Channel Heated Asymmetrically With Large Temperature Differences
Authors: Pantokratoras Asterios
Published: December 2007

In this paper, we study the steady laminar flow in a fluid-saturated porous medium channel bounded by two parallel plates with constant but unequal temperatures. One plate is moving with constant velocity while the other is stationary. For the porous medium, the Brinkman–Darcy–Forchheimer model is used. The investigation concerns engine oil, water, and air, taking into account the variation of their physical properties with temperature. The results are obtained with the direct numerical solution of the governing equations and cover large temperature differences. It is found that dynamic viscosity plays an important role on the results, which depart significantly from those of a fluid with constant properties when the temperature difference between the plates is large. Except that there are cases where the flow is restricted near the moving plate while at the lower part of the channel, the fluid is motionless.
Novel Characteristics of Community-Acquired Methicillin-Resistant
Staphylococcus aureus
Strains Belonging to Multilocus Sequence Type 59 in Taiwan
Authors: Takano Tomomi , Higuchi Wataru , Otsuka Taketo , Baranovich Tatiana , Enany Shymaa , Saito Kohei , Isobe Hirokazu , Dohmae Soshi , Ozaki Kyoko , Takano Misao , Iwao Yasuhisa , Shibuya Michiko , Okubo Takeshi , Yabe Shizuka , Shi Da , Reva Ivan , Teng Lee-Jene , Yamamoto Tatsuo
Published: December 2007

Community-acquired methicillin-resistant
Staphylococcus aureus
(CA-MRSA) strains, which often produce Panton-Valentine leucocidin (PVL), are increasingly noted worldwide. In this study, we examined 42 MRSA strains (25 PVL-positive [PVL
+
] strains and 17 PVL-negative [PVL
−
] strains) isolated in Taiwan for their molecular characteristics. The PVL
+
MRSA strains included CA-MRSA strains with multilocus sequence type (ST) 59 (major PVL
+
MRSA in Taiwan), its variants, and worldwide CA-MRSA ST30 strains. The PVL
−
MRSA strains included the pandemic Hungarian MRSA ST239 strain, the Hungarian MRSA ST239 variant, MRSA ST59 (largely hospital-acquired MRSA strains) and its variants, the pandemic New York/Japan MRSA ST5 strain (Japanese type), and the MRSA ST8 strain. The major PVL
+
CA-MRSA ST59 strain possessed a tetracycline resistance-conferring (
tetK
positive) penicillinase plasmid and a drug resistance gene cluster (a possible composite transposon) for multidrug resistance. Moreover, it carried a novel staphylococcal cassette chromosome
mec
(SCC
mec
) with two distinct
ccrC
genes (
ccrC2
-
C8
). This SCC
mec
(previously named SCC
mec
type V
T
) was tentatively designated SCC
mec
type VII. Sequencing of the PVL genes revealed the polymorphisms, and the PVL
+
CA-MRSA ST59 strain possessed the ST59-specific PVL gene sequence. The data suggest that a significant amount of clonal spread is occurring in Taiwan and that the major PVL
+
CA-MRSA ST59
Taiwan
strain exhibits unique genetic characteristics, such as a novel SCC
mec
type and an ST59-specific PVL gene sequence.
LOW-DIMENSIONAL QUANTUM TRANSPORT PROPERTIES OF CHEMICALLY-DISORDERED CARBON NANOTUBES: FROM WEAK TO STRONG LOCALIZATION REGIMES
Authors: AVRILLER REMI , ROCHE STEPHAN , TRIOZON FRANCOIS , BLASE XAVIER , LATIL SYLVAIN
Published: December 2007

In this review, the quantum transport of nitrogen-doped metallic carbon nanotubes under magnetic field are explored. An accurate modeling of chemical disorder effects is derived from ab initio calculations. General properties for low bias Landauer conductance are investigated in the coherent regime, which enlighten the strong interplay between band structure and quantum interference effects. Characteristic transport length scales such as the elastic mean free path and localization length are extracted from phenomenological laws as well as scaling features with nanotube radius and doping level. The statistical analysis of conductance properties allow us to study the transition between weak and strong localization regimes.
ENERGY EXCHANGE RATE IN NON-DEGENERATE ELECTRON GAS CONFINED TO A GaAs HETEROSTRUCTURE
Authors: TRIPATHI P. , SHARMA A. C.
Published: December 2007

The rate of energy exchange via dynamically screened electron–electron interaction in a two-dimensional and quasi two-dimensional semiconductor is described analytically for the situation where the electron gas obeys classical statistics and is therefore applicable to many cases involving hot-electrons. It is shown that the interaction is resonantly enhanced by coupled-phonon–plasmon mode effects. The magnitudes of energy and momentum exchange rates in GaAs suggest that in cases where optical phonon scattering is not dominant, hot-electron transport will be describable in terms of drifted Maxwellian distribution. Even where optical-phonon scattering is dominant, the coupled phonon–plasmon mode enhancement of the electron–electron energy exchange rate offers substantial contribution.
GROWTH AND CHARACTERIZATION OF NONLINEAR OPTICAL PARA-NITROANILINE (pNA) SINGLE CRYSTALS
Authors: BARANIRAJ T. , PHILOMINATHAN P. , VIJAYAN N.
Published: December 2007

Single crystals of para Nitroaniline ( pNA ), an organic nonlinear optical (NLO) material, have been grown by slow solvent evaporation technique at room temperature. Good optical quality single crystals with dimensions of up to 10 × 11 × 3 mm 3 have been grown by adopting the above technique, and good quality single crystals were obtained. The grown single crystals were subjected to different characterization analyses. The lattice dimensions have been determined from the powder X-ray diffraction analysis. Its functional groups and optical behavior have been identified from the FTIR and UV-Vis. analyses respectively. The thermal stability of the crystal has been analyzed by thermogravimetric (TG) and differential thermal (DT) analyses respectively.
Introduction
Authors: Mortimore R.N. , Duperret A.
Published: December 2007

In 1998 a European funded research programme ROCC (Risk of Cliff Collapse) was initiated by a team from France and the UK because of the growing hazard to local commu-nities from chalk cliff retreat. Could the where, when and how of cliff collapses be answered and could the rate and scale of cliff retreat be modelled more accurately? Such answers are vital to the planners and local authorities respon-sible for the safety and access to cliffs and beaches. The primary research area is the eastern English Channel, where in northeast France there is 120km of Chalk coast, and in southeast England 40km in Sussex and a similar length in Kent. The research programme brought together geologists and engineers from BRGM, the University of Le Havre and the University of Brighton in partnership with the regional governments of the Somme, Seine Maritime, southeast England and their constituent local authorities. This book, representing several years of previous and concurrent research on the engineering geology of chalk and coastal pro-cesses, is the outcome of that research programme and allied work.

It was fortuitous that several other chalk investigations were coming to completion prior to ROCC starting. These formed a foundation on which to build the investigations. In particular, a refined Chalk lithostratigraphy with practical application to mapping and detailed correlation, was finally accepted by a joint stratigraphic committee of the Geological Society and the British Geological Survey in September 1999 (Mortimore 1986; Bristow et al. 1997; Rawson et al. 2001). This meant that