bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel approach to studying the effects of temperature on soil biogeochemistry using a thermal gradient bar
Authors: Fenner N. , Dowrick D. J. , Lock M. A. , Rafarel C. R. , Freeman C.
Published: June 2006

The temperature dependence of chemical reaction rates and microbial metabolism mean that temperature is a key factor regulating soil trace gas emissions and hydrochemistry. Here we evaluated a novel approach for studying the thermal response of soils, by examining the effects of temperature on gas emissions and hydrochemistry in (a) peat and (b) soil from a Sitka spruce plantation. A thermal gradient was applied along an aluminium bar, allowing soil to be incubated contemporaneously from 2 to 18 °C. The approach demonstrated clear differences in the biogeochemical responses of the two soil types to warming. The peat showed no significant emission of CH4 at temperatures below 6 °C, while above 6 °C, a marked increase in the rate of release was apparent up to 15 °C (Q10 = 2.5) with emissions being similar between 15 and 18 °C. Conversely, CH4 emissions from the forest soil did not respond to warming. Nitrate availability in the peat decreased by 90% between 2 and 18 °C (P < 0.01), whereas concentrations in the forest soil did not respond. Sulphate availability in the peat decreased significantly with warming (60%, P < 0.01), while the forest soil showed the opposite response (a 30% increase, P < 0.01). Conventionally, thermal responses are studied by incubating individual soil samples at different temperatures, involving lengthy preparation and facilities to incubate samples at different temperatures simultaneously. Data collected on a given thermal response is usually limited and thus interpolated or extrapolated. The thermal gradient method overcomes these problems, is simple and flexible, and can be adapted for a wide range of sample types (not confined to soil). Such apparatus may prove useful in the optimization of management practices to mitigate the effects of climate change, as thermal responses will differ depending on land use and soil type.
Crystallization Kinetics and Phase Development of PbO–BaO–SrO–Nb2O5–B2O3–SiO2‐Based Glass–Ceramics
Authors: Cheng Ching‐Tai , Lanagan Michael , Jones Beth , Lin Jiang‐Tsair , Pan Ming‐Jen
Published: June 2006

The nucleation and crystallization kinetics of PbO–BaO–SrO–Nb2O5–B2O3–SiO2‐based glass–ceramics have been investigated. Strontium barium niobate (Sr0.33Ba0.67Nb2O6) with a tetragonal tungsten–bronze structure formed as the major crystalline phase, which nucleates and grows on the surface region of samples. The results of the present study showed an apparent activation energy of 193 kJ/mol for nucleation, which was controlled by the viscous flow of the glass. Quantitative X‐ray analysis and differential thermal analysis showed that the rate‐limiting mechanism of crystallization appeared to be a three‐dimensional interfacial growth, which has an apparent activation energy of 386–430 kJ/mol, a value that is close to the dissociation of Si–O bonds in the glass system.
Gibbs Energy Change of Carbothermal Nitridation Reaction of γ‐AlON and Its Thermodynamic Stability
Authors: Nakao Wataru , Fukuyama Hiroyuki
Published: June 2006

In order to determine the standard Gibbs energy change of carbothermal nitridation reaction of γ‐aluminum oxynitride spinel, γ‐AlON, the equilibrium N2–CO gas compositions coexisting with γ‐AlON, aluminum nitride (AlN), and graphite have been measured by means of gas chromatography at elevated temperatures. From the results obtained, the standard Gibbs energy change has been determined at temperatures ranging from 1912 to 2002 K,
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where γ‐AlON is expressed as Al(64+x)/3V(8−x)/3O32−xNx (V: vacancy). Moreover, the thermodynamic stability in the homogeneous phase region of γ‐AlON has been evaluated by a thermodynamic model of γ‐AlON together with the experimental results.
Measurement of the Thermophysical Properties of a Thermoplastic Ceramic Paste Across its Solidification Range Using Power‐Compensated Differential Scanning Calorimeter
Authors: Barker Dean A. , Ian Wilson D.
Published: June 2006

The specific heat capacity, thermal conductivity, and thermal diffusivity of a thermoplastic ceramic paste were investigated on a power‐compensated, differential scanning calorimeter (DSC) using the heat capacity spectral analysis method developed by Merzlyakov and Schick for measuring these parameters on low thermal conductivity solids. The paste features an ultra‐fine zinc oxide powder (a number‐length mean diameter, D1,0, of 85 nm) as the discrete phase, and a thermoplastic continuous phase comprising a blend of organic waxes with a melting range of ca. 30°–70°C. This paste is formulated with a solids loading of 50 vol% and is currently used in a novel continuous casting process to manufacture pharmaceutical products. The properties of the paste were investigated over a temperature range encompassing the melt and solid states, and for solid loadings from 0 to 70 vol%. The results compare favorably with those obtained using transient line source and transient plane methods.
Tribological Properties of Ti3SiC2
Authors: Sarkar D. , Basu B. , Cho S. J. , Chu M. C. , Hwang S. S. , Park S. W.
Published: June 2006

The present contribution reports the unlubricated friction and wear properties of Ti3SiC2 against steel. The fretting experiments were performed under varying load (1–10 N) and the detailed wear mechanism is studied using SEM‐EDS, Raman spectroscopy, and atomic force microscopy. Under the selected fretting conditions, Ti3SiC2/steel tribocouple exhibits a transition in friction as well as wear behavior with coefficient of friction varying between 0.5 and 0.6 and wear rate in the order of 10−5 mm3·(N·m)−1. Raman analysis reveals that the fretting wear is accompanied by the triboxidation with the formation of TiO2, SiO2, and Fe2O3. A plausible explanation for the transition in friction and wear with load is proposed.
Kinetics on a Second Scale at Temperatures up to 2300 K—The Reduction of Manganese Oxide in a Solar Furnace
Authors: Frey Thomas , Guesdon Christine , Sturzenegger Marcel
Published: June 2006

Testing the chemical stability of high‐performance ceramics at temperatures above 1800 K is a demanding task. With the aim to provide an experimental set‐up for kinetic studies on gas releasing reactions at temperatures up to 2300 K, a solar reactor has been interfaced to a mass spectrometer. Tracer experiments revealed that the reactor behaves as a continuous ideally stirred tank. This characteristic provides a straightforward path to extract kinetic data for such reactions from gas‐phase analysis. The approach is demonstrated by presenting results of a study on the solar thermal reduction of manganese oxide at 2200 K.
Conversion of Fly Ash—An Environmentally Detrimental Waste to Zeolite Beta (BEA) for Commercial Catalytic Applications
Authors: Kasture Mahesh W. , Bokade Vijay V. , Joshi Praphulla N.
Published: June 2006

Zeolite beta (BEA) was synthesized hydrothermally using fly ash as a combined source of alumina and silica. The overall crystallization period required to obtain pure crystalline BEA zeolite was found to be slightly longer when fly ash was used. The physicochemical properties of BEA phases obtained using fly ash (FLBEA) and conventional source materials (CONBEA) were compared. The H/FLBEA catalyst has exhibited excellent catalytic performance in commercially important benzene isopropylation process. These results have demonstrated that converting fly ash into BEA zeolite not only alleviates the disposal problem but also turns an otherwise waste material into a marketable commodity.
Early Stages of Crystallization in Canasite‐Based Glass Ceramics
Authors: Kanchanarat Naruporn , Miller Cheryl A. , Hatton Paul V. , James Peter F. , Reaney Ian M.
Published: June 2006

Previous work by Miller et al. (2000–2004) has demonstrated that canasite‐based glass ceramics have potential for use as biocompatible glass ceramics in hard‐tissue augmentation. Several compositional modifications with respect to the stoichiometric formula (K2Na4Ca5Si12O30F4) were studied and biocompatibility in simulated body fluid was reported. However, the mechanism(s) of crystallization were not investigated in detail. The purpose of this study was to examine the early stages of nucleation and growth in four glass compositions using X‐ray diffraction and transmission electron microscopy. In stoichiometric compositions (CAN1), laths of predominantly frankamenite homogeneously nucleate throughout the glass at ∼700°C without the presence of a nucleating phase. However, in Na2O‐deficient compositions (CAN2), CaF2 particles (650°C) act as nucleating sites for canasite laths (700°C). In CaO‐rich compositions (CAN3), CaF2 particles (650°C) once again act as nucleating sites but for xonotlite (700°C) rather than canasite laths. Instead, frankamenite and canasite crystallize to become the dominant phases at >700°C. In P2O5‐modified compositions (CAN4), CaF2 and fluorapatite, present on cooling, act as nucleating agents for canasite (750°C).
Formation and Properties of Chalcogenide Glasses in the GeSe2–As2Se3–CdSe System
Authors: Donghui Zhao , Fang Xia , Guorong Chen , Xianghua Zhang , Hongli Ma , Adam J. L.
Published: June 2006

The glass‐forming region in a GeSe2–As2Se3–CdSe system and the dependence of properties on glass compositions as a formula of 70GeSe2–(30−x)As2Se3–xCdSe (x=0–25) were investigated. Measurements included density, micro‐hardness, differential scanning calorimetry (DSC), X‐ray diffraction, and IR transmission spectra. A large glass‐forming region was shown while addition of Cd increases the crystallization trend of the system. Besides, the Cd content accommodated by the system to form glass is found to be lower in the As2Se3‐rich region than in the GeSe2‐rich region. With the introduction of CdSe, density, micro‐hardness, and Tg of glasses increase whereas an exothermal peak in the DSC curve appears and thermal stability (ΔT) decreases. The activation energy of crystallization and the Avrami exponent were also obtained using the modified Ozawa equation.
Impedance Spectroscopy as a Tool for Chemical and Electrochemical Analysis of Mixed Conductors: A Case Study of Ceria
Authors: Lai Wei , Haile Sossina M.
Published: June 2006

The AC impedance response of mixed ionic and electronic conductors (MIECs) is derived from first principles and quantitatively compared with experimental data. While the approach is not entirely new, the derivation is provided in a unified and comprehensive manner. Using Sm0.15Ce0.85O1.925–δ with Pt electrodes as a model system, a broad spectrum of electrical and thermodynamic properties is extracted solely from the measurement of impedance spectra over wide oxygen partial pressure and temperature ranges. Here, the oxygen partial pressure was varied from air [po2=0.21 atm] to H2 [po2=10−31 atm], and the temperature was varied from 500° to 650°C. It was essential for this analysis that the material under investigation exhibit, under some conditions, purely ionic behavior and, under others, mixed conducting behavior. The transition from ionic to mixed conducting behavior is recognizable not only from the oxygen partial pressure dependence of the total conductivity but also directly from the shape of the impedance spectra. Within the electrolytic regime, the impedance spectra (presented in Nyquist form) take the shape of simple, depressed arcs, whereas within the mixed conducting regime (under reducing conditions), the spectra exhibit the features associated with a half tear‐drop‐shaped element. Parameters derived from quantitative fitting of the impedance spectra include the concentration of free electron carriers, the mobilities and activation energies for both ion and electron transport, the electrolytic domain boundary, and the entropy and enthalpy of reduction. In addition, the electrochemical behavior of O2 and H2 at the Pt∣ceria interface has been characterized from these measurements. Under oxidizing conditions, the data suggest an oxygen electrochemical reaction that is rate limited by the dissociated adsorption/diffusion of oxygen species on the Pt electrode, similar to Pt∣YSZ (yttria‐stabilized zirconia). Under reducing conditions, the inverse of the electrode resistivity obeys a

dependence, with an activation energy that is similar to that measured for the electronic conductivity. These results suggest that ceria is electrochemically active for hydrogen electro‐oxidation and that the reaction is limited by the rate of removal of electrons from the ceria surface.
Serum concentrations of risperidone and 9‐OH risperidone following intramuscular injection of long‐acting risperidone compared with oral risperidone medication
Authors: Nesvåg R. , Hendset M. , Refsum H. , Tanum L.
Published: June 2006

Objective:  To compare serum concentrations of risperidone, 9‐hydroxy (OH) risperidone and risperidone plus 9‐OH risperidone, as well as the 9‐OH risperidone/risperidone ratio in patients receiving depot and oral risperidone.

Method:  Serum concentrations from 78 patients receiving three different doses of risperidone depot were measured and compared with serum concentrations from 82 patients taking three different doses of oral risperidone.

Results:  Patients receiving risperidone depot had significantly lower serum concentrations of risperidone plus 9‐OH risperidone than patients taking oral risperidone. More interestingly, the 9‐OH risperidone/risperidone ratio was also significantly lower in patients receiving risperidone depot than in patients taking oral risperidone.

Conclusion:  Serum concentrations of risperidone plus 9‐OH risperidone may be a rather poor indication of the antipsychotic efficacy of risperidone unless their ratio is also considered.
A Mutation in Epstein–Barr Virus LMP2A Reveals a Role for Phospholipase D in B‐Cell Antigen Receptor Trafficking
Authors: Snyder Michelle D. , Pierce Susan K.
Published: June 2006

Epstein–Barr virus (EBV) latent infection of B cells blocks the interrelated signaling and antigen‐trafficking functions of the BCR through the activity of its latent membrane protein 2A (LMP2A). At present, the molecular mechanisms by which LMP2A exerts its control of BCR functions are only poorly understood. Earlier studies showed that in B cells expressing LMP2A containing a tyrosine mutation at position 112 in its cytoplasmic domain (Y112‐LMP2A), the BCR could initiate signaling but could not properly traffic antigen for processing. Here, we show that BCR signaling in Y112‐LMP2A‐expressing cells is attenuated with a reduction in both the degree and duration of phosphorylation of key components of the BCR signaling cascade including Syk, BLNK, PI3K, and Btk. Notably, Y112‐LMP2A expression completely blocked the BCR‐induced activation of phospholipase D (PLD), a lipase implicated in the intracellular trafficking of a variety of surface receptors. We show that blocking PLD activity, by expressing Y112‐LMP2A, treating cells with the PLD inhibitor 1‐butanol or reducing PLD expression by siRNA, blocked BCR trafficking to class II‐containing compartments. Moreover, Y112‐LMP2A expression blocked the recruitment of phosphorylated forms of the downstream BCR signaling components, Erk and JNK, through both PLD‐dependent and PLD‐independent mechanisms. Thus, the investigation of the mechanism by which Y112‐LMP2A blocks BCR function revealed an essential role for PLD in BCR trafficking for antigen processing.
GENEGEN TECHNOLOGY FOR DETECTION OF SALMONELLA SPP. AND GENUS LISTERIA/LISTERIA MONOCYTOGENES IN CHICKEN SAMPLES
Authors: VOLLENHOFER‐SCHRUMPF SABINE , BURESCH RONALD , UNGER GABRIELE , STAHL NICOLE , FRÄNZL GERT , SCHINKINGER MANFRED
Published: June 2006

Performances of two commercial test systems for the detection of Salmonella spp. and genus Listeria/Listeria monocytogenes (GeneGen Salmonella Detection Kit and GeneGen Listeria Detection Kit, respectively) were tested. The technology combines multiplex polymerase chain reaction with a shortened, simplified hybridization protocol using test strips. In specificity tests using a collection of over 80 bacterial strains representing 22 genera, no false positive or false negative results were observed. The limit of detection was 100 and 10 genome copies for the Salmonella and Listeria assays, respectively. The kits were used for both analyses of spiked and naturally contaminated chicken samples, and their performances were compared with standard methods. An amount of 1–10 cfu/25 g of the respective pathogen added could be detected. Results achieved with the GeneGen Salmonella Detection Kit were in 100% concordance with the microbiological protocol. The GeneGen Listeria Detection Kit proved to be more sensitive than the standard method in the spiking experiments, as well as for chicken samples naturally contaminated with both Listeria innocua and L. monocytogenes. The kits provided a time saving of several days compared to conventional methods (30‐h detection time for Salmonella, 30–54 h for Listeria). The protocol is simple and does not require any high‐tech equipment for evaluation or documentation after DNA amplification. Hybridization can be carried out at ambient temperature, and results are evaluated with the unaided eye. Thus, these kits could be a valuable tool for the screening of food samples and confirmation of suspect colonies, especially in modestly equipped laboratories.
BIPHASIC MICROTITER METHOD FOR CAMPYLOBACTER RECOVERY AND ENUMERATION
Authors: ERIC LINE J. , SIRAGUSA GREGORY R.
Published: June 2006

We developed a biphasic method for recovery and enumeration of campylobacters. The biphasic system was composed of 96‐well microtiter plates containing Campy–Line agar prepared 2× for all ingredients except for 1× agar (0.1 mL per well). Samples were prepared in either twofold or fivefold dilution series across separate 96‐well plates and directly transferred (0.1 mL) to the agar‐containing microtiter plates to create the biphasic system. Biphasic plates were incubated for up to 48 h at 42C either aerobically or microaerobically in a gas mixture of 5% O2, 10% CO2 and 85% N2. Campylobacter was recovered in the aerobically incubated biphasic plates; however, significantly greater Campylobacter recovery was obtained in the biphasic plates incubated microaerobically (P < 0.05). Significantly higher numbers of injured campylobacters from chicken carcass rinse samples were recovered by the biphasic method compared with conventional direct plating techniques (P < 0.05).
Activation of Non‐neuronal Cells within the Prenatal Developing Brain of Sheep with Neuronal Ceroid Lipofuscinosis
Authors: Kay Graham W. , Palmer David N. , Rezaie Payam , Cooper Jonathan D.
Published: June 2006

The neuronal ceroid lipofuscinoses (NCLs, Batten disease) are fatal inherited lysosomal storage diseases of children characterized by increasing blindness, seizures and profound neurodegeneration but the mechanisms leading to these pathological changes remain unclear. Sheep with a CLN6 form that have a human‐like brain and disease progression are invaluable for studying pathogenesis. A study of preclinical pathology in these sheep revealed localized glial activation at only 12 days of age, particularly in cortical regions that subsequently degenerate. This has been extended by examining fetal tissue from 60 days of gestation onwards. A striking feature was the presence of reactive astrocytes and the hypertrophy and proliferation of perivascular cells noted within the developing white matter of the cerebral cortex 40 days before birth. Astrocytic activation was evident within the cortical gray matter 20 days before birth, and was confined to the superficial laminae 12 days after birth. Clusters of activated microglia were detected in upper neocortical gray matter laminae shortly after birth. Neuronal development in affected sheep was undisturbed at these early ages. This prenatal activation of non‐neuronal cells within the affected brain indicates the onset of pathogenesis during brain development and that an ordered sequence of glial activation precedes neurodegeneration.
Redefining Cellular Phenotypy Based on Embryonic, Adult, and Cancer Stem Cell Biology
Authors: Steindler Dennis A.
Published: June 2006

Stem cell biology has provided constant alteration if not reversal of dogma related to the understanding of the behaviors of primitive and dynamic cells. This review summarizes recent findings on dynamic changes of phenotype that accompany the in vitro growth and differentiation of not only stem and progenitor cells, but also differentiated cells derived from a variety of normal and pathological tissues. As there are examples of apparent dedifferentiation and transdifferentiation of neural cells that appear to be terminally differentiated, there is a need to reconsider elements of cellular fate choice that have relevance to neurooncology and neural repair. Recent findings of dynamic behaviors and mixed phenotype of both normal and cancer stem cells suggest that some of the diverse lineage attributes of different solid tumors may owe their existence to dynamic cellular phenotypy gone awry.
The Breakup of a Main-Belt Asteroid 450 Thousand Years Ago
Authors: Nesvorný David , Vokrouhlický David , Bottke William F.
Published: June 2006

Collisions in the asteroid belt frequently lead to catastrophic breakups, where more than half of the target's mass is ejected into space. Several dozen large asteroids have been disrupted by impacts over the past several billion years. These impact events have produced groups of fragments with similar orbits called asteroid families. Here we report the discovery of a very young asteroid family around the object 1270 Datura. Our work takes advantage of a method for identification of recent breakups in the asteroid belt using catalogs of osculating (i.e., instantaneous) asteroid orbits. The very young families show up in these catalogs as clusters in a five-dimensional space of osculating orbital elements.
Tim50 Maintains the Permeability Barrier of the Mitochondrial Inner Membrane
Authors: Meinecke Michael , Wagner Richard , Kovermann Peter , Guiard Bernard , Mick David U. , Hutu Dana P. , Voos Wolfgang , Truscott Kaye N. , Chacinska Agnieszka , Pfanner Nikolaus , Rehling Peter
Published: June 2006

Transport of metabolites across the mitochondrial inner membrane is highly selective, thereby maintaining the electrochemical proton gradient that functions as the main driving force for cellular adenosine triphosphate synthesis. Mitochondria import many preproteins via the presequence translocase of the inner membrane. However, the reconstituted Tim23 protein constitutes a pore remaining mainly in its open form, a state that would be deleterious in organello. We found that the intermembrane space domain of Tim50 induced the Tim23 channel to close. Presequences overcame this effect and activated the channel for translocation. Thus, the hydrophilic cis domain of Tim50 maintains the permeability barrier of mitochondria by closing the translocation pore in a presequence-regulated manner.
DYNAMICS AND UNIVERSALITY OF AN ISOTHERMAL COMBUSTION PROBLEM IN 2D
Authors: QI Y. W.
Published: June 2006

In this paper, the Cauchy problem of the system [Formula: see text] is studied, where x ∈ R2, m ≥ 1 and d > 0 is the Lewis number. This system models isothermal combustion (see [7]), and auto-catalytic chemical reaction. We show the global existence and regularity of solutions with non-negative initial values having mild decay as |x| → ∞. More importantly, we establish the exact spatio-temporal profiles for such solutions. In particular, we prove that for m = 1, the exact large time behavior of solutions is characterized by a universal, non-Gaussian spatio-temporal profile, with anomalous exponents, due to the fact that quadratic nonlinearity is critical in 2D. Our approach is a combination of iteration using Renormalization Group method, which has been developed into a very powerful tool in the study of nonlinear PDEs largely by the pioneering works of Bricmont, Kupiainen and Lin [6], Bricmont, Kupiainen and Xin, [7], (see also [9]) and key estimates using the PDE method.
APPLICATIONS OF DENSITY MATRICES IN A TRAPPED BOSE GAS
Authors: CH. CHATZISAVVAS K. , MASSEN S. E. , MOUSTAKIDIS CH. C. , PANOS C. P.
Published: June 2006

An overview of the Bose–Einstein condensation of correlated atoms in a trap is presented by examining the effect of interparticle correlations to one- and two-body properties of the above systems at zero temperature in the framework of the lowest order cluster expansion. Analytical expressions for the one- and two-body properties of the Bose gas are derived using Jastrow-type correlation function. In addition numerical calculations of the natural orbitals and natural occupation numbers are also carried out. Special effort is devoted for the calculation of various quantum information properties including Shannon entropy, Onicescu informational energy, Kullback–Leibler relative entropy and the recently proposed Jensen–Shannon divergence entropy. The above quantities are calculated for the trapped Bose gases by comparing the correlated and uncorrelated cases as a function of the strength of the short-range correlations. The Gross–Piatevskii equation is solved, giving the density distributions in position and momentum space, which are employed to calculate quantum information properties of the Bose gas.
CONTINUOUS-TIME QUANTUM WALKS ON TREES IN QUANTUM PROBABILITY THEORY
Authors: KONNO NORIO
Published: June 2006

A quantum central limit theorem for a continuous-time quantum walk on a homogeneous tree is derived from quantum probability theory. As a consequence, a new type of limit theorems for another continuous-time walk introduced by the walk is presented. The limit density is similar to that given by a continuous-time quantum walk on the one-dimensional lattice.
A SIMPLE PROOF OF THE FUNDAMENTAL THEOREM ABOUT ARVESON SYSTEMS
Authors: SKEIDE MICHAEL
Published: June 2006

With every E0-semigroup (acting on the algebra of of bounded operators on a separable infinite-dimensional Hilbert space) there is an associated Arveson system. One of the most important results about Arveson systems is that every Arveson system is the one associated with an E0-semigroup. In these notes we give a new proof of this result that is considerably simpler than the existing ones and allows for a generalization to product systems of Hilbert module (to be published elsewhere).
Ca2+ Enhances U-Type Inactivation of N-Type (CaV2.2) Calcium Current in Rat Sympathetic Neurons
Authors: Goo Yong Sook , Lim Wonil , Elmslie Keith S.
Published: June 2006

Ca2+-dependent inactivation (CDI) has recently been shown in heterologously expressed N-type calcium channels (CaV2.2), but CDI has been inconsistently observed in native N-current. We examined the effect of Ca2+ on N-channel inactivation in rat sympathetic neurons to determine the role of CDI on mammalian N-channels. N-current inactivated with fast (τ ∼ 150 ms) and slow (τ ∼ 3 s) components in Ba2+. Ca2+ differentially affected these components by accelerating the slow component (slow inactivation) and enhancing the amplitude of the fast component (fast inactivation). Lowering intracellular BAPTA concentration from 20 to 0.1 mM accelerated slow inactivation, but only in Ca2+ as expected from CDI. However, low BAPTA accelerated fast inactivation in either Ca2+ or Ba2+, which was unexpected. Fast inactivation was abolished with monovalent cations as the charge carrier, but slow inactivation was similar to that in Ba2+. Increased Ca2+, but not Ba2+, concentration (5–30 mM) enhanced the amplitude of fast inactivation and accelerated slow inactivation. However, the enhancement of fast inactivation was independent of Ca2+ influx, which indicates the relevant site is exposed to the extracellular solution and is inconsistent with CDI. Fast inactivation showed U-shaped voltage dependence in both Ba2+ and Ca2+, which appears to result from preferential inactivation from intermediate closed states (U-type inactivation). Taken together, the data support a role for extracellular divalent cations in modulating U-type inactivation. CDI appears to play a role in N-channel inactivation, but on a slower (sec) time scale.
Behavioral Evaluation of Movement Cancellation
Authors: Walton Mark M. G. , Gandhi Neeraj J.
Published: June 2006

The countermanding saccade task has been used in many studies to investigate the neural mechanisms that underlie the decision to execute or restrain rapid eye movements. In this task, the presentation of a saccade target is sometimes followed by the appearance of a stop cue that indicates that the subject should cancel the planned movement. Performance has been modeled as a race between motor preparation and cancellation processes. The signal that reaches its activation threshold first determines whether a saccade is generated or cancelled. In these studies, an important parameter is the time required to process the stop cue, referred to as the stop signal reaction time (SSRT). The SSRT is estimated using statistical approaches, the validity of which has not been unequivocally established. A more direct measure of this parameter might be obtainable if a method was available to “unmask” the developing motor command. This can be accomplished by air-puff-evoked blinks, which inhibit pontine omnipause neurons that serve as an inhibitory gate for the saccadic system. In the present study, brief puffs of air were used to elicit blinks at various times while rhesus monkeys performed a countermanding saccade task. If the developing motor command has not yet been cancelled, this should trigger a saccade. When blinks occurred between ∼50 and 200 ms after target onset, saccades were often evoked. Saccades were rarely evoked more than ∼70 ms after stop cue onset; this value represents a behavioral evaluation of SSRT and was comparable to the estimates obtained using standard statistical approaches. When saccades occurred near the SSRT on blink trials, they were often hypometric. Furthermore, Monte Carlo simulations were performed to model the effects of blink time on the race model. Overall, the study supports the validity of the statistical methods currently in use.
The Role of Scales in the Dynamics of Parameterization Uncertainties
Authors: Vannitsem S.
Published: June 2006

The dynamics of model error due to parameterization uncertainties are investigated in the context of two spatially distributed systems: the one-dimensional convection system known as the extended Kuramoto–Sivashinsky equation and a quasigeostrophic atmospheric model. In addition to the different phases of error growth already reported for low-order systems, unexpected behaviors associated with the spectral characteristics of the model perturbation sources have been brought out. Notably, the predictability of the system is less affected by model uncertainties acting at small scales than at larger ones. An interpretation in terms of the spectral properties of the Lyapunov vectors is advanced.
Effect of Extrusion Rate and Fiber Loading on Mechanical Properties of Twaron Fiber-thermoplastic Natural Rubber (TPNR) Composites
Authors: Ahmad Ishak , Baharum Azizah , Abdullah Ibrahim
Published: June 2006

Mechanical behavior of short Twaron fiber thermoplastic natural rubber (TPNR) has been studied with respect to fiber loading and extrusion rates. The composites are prepared at two different compositions of NR/LLDPE matrixes i.e., 60/40 and 40/60. Twaron fibers are varied from 0 to 25% in the composites. The temperature profile for extrusion is 140, 145, 150, and 155°C for feeding zone, melting zone, mixing zone, and die respectively with the extrusion rate of 30, 50, 80, and 100 rpm. It has been found that the tensile strength, Young’s modulus, and impact strength increases with fiber loading, but the strain at break decreases. The optimum fiber loading in the system is found to be 20% in both blends. However, there is no effect of extrusion rate on the strength of composite observed.
A new approach to treatment of resistant gram-positive infections: potential impact of targeted IV to oral switch on length of stay
Authors: Desai Mohammed , Franklin Bryony Dean , Holmes Alison H , Trust Sarah , Richards Mike , Jacklin Ann , Bamford Kathleen B
Published: June 2006

Background

Patients prescribed intravenous (IV) glycopeptides usually remain in hospital until completion of this treatment. Some of these patients could be discharged earlier if a switch to an oral antibiotic was made. This study was designed to identify the percentage of inpatients currently prescribed IV glycopeptides who could be discharged earlier if a switch to an oral agent was used, and to estimate the number of bed days that could be saved. We also aimed to identify the patient group(s) most likely to benefit, and to estimate the number of days of IV therapy that could be prevented in patients who remained in hospital.

Methods

Patients were included if they were prescribed an IV glycopeptide for 5 days or more. Predetermined IV to oral antibiotic switch criteria and discharge criteria were applied. A multiple logistic regression model was used to identify the characteristics of the patients most likely to be suitable for earlier discharge.

Results

Of 211 patients, 62 (29%) could have had a reduced length of stay if they were treated with a suitable oral antibiotic. This would have saved a total of 649 inpatient days (median 5 per patient; range 1–54). A further 31 patients (15%) could have switched to oral therapy as an inpatient thus avoiding IV line use. The patients most likely to be suitable for early discharge were those with skin and soft tissue infection, under the cardiology, cardiothoracic surgery, orthopaedics, general medical, plastic surgery and vascular specialities, with no high risk comorbidity and less than five other regularly prescribed drugs.

Conclusion

The need for glycopeptide therapy has a significant impact on length of stay. Effective targeting of oral antimicrobials could reduce the need for IV access, allow outpatient treatment and thus reduce the length of stay in patients with infections caused by antibiotic resistant gram-positive bacteria.
Association between disruption of CD4 receptor dimerization and increased human immunodeficiency virus type 1 entry
Authors: Bourgeois Rachel , Mercier Johanne , Paquette-Brooks Isabelle , Cohen Éric A
Published: June 2006

Background

Human immunodeficiency virus (HIV) enters target cells by a membrane fusion process that involves a series of sequential interactions between its envelope glycoproteins, the CD4 receptor and CXCR4/CCR5 coreceptors. CD4 molecules are expressed at the cell surface of lymphocytes and monocytes mainly as monomers, but basal levels of CD4 dimers are also present at the cell surface of these cells. Previous evidence indicates that the membrane distal and proximal extracellular domains of CD4, respectively D1 and D4, are involved in receptor dimerization.

Results

Here, we have used A201 cell lines expressing two CD4 mutants, CD4-E91K, E92K (D1 mutant) and CD4-Q344E (D4 mutant), harboring dimerization defects to analyze the role of CD4 dimerization in HIV-1 entry. Using entry assays based on β-lactamase-Vpr or luciferase reporter activities, as well as virus encoding envelope glycoproteins derived from primary or laboratory-adapted strains, we obtained evidence suggesting an association between disruption of CD4 dimerization and increased viral entry efficiency.

Conclusion

Taken together, our results suggest that monomeric forms of CD4 are preferentially used by HIV-1 to gain entry into target cells, thus implying that the dimer/monomer ratio at the cell surface of HIV-1 target cells may modulate the efficiency of HIV-1 entry.
cultural geographies in practice
Authors: Yusoff Kathryn , Gabrys Jennifer
Published: June 2006

Imagine yourself in Central Park one million years ago. You would be standing on a vast ice sheet, a 4,000-mile glacial wall, as much as 2,000 feet thick. Alone on the vast glacier, you would not sense its slow crushing, scraping, ripping movement as it advanced south, leaving great masses of rock debris in its wake. Under the frozen depths, where the carousel now stands, you would notice the effect on the bedrock as the glacier dragged itself along.1
Politics of belonging in the construction of landscapes: place-making, boundary-drawing and exclusion
Authors: Trudeau Daniel
Published: June 2006

Issues of belonging, exclusion and the creation and maintenance of boundaries have surfaced in recent considerations of the production of space, yet the relevance of boundaries and belonging for understanding the construction of landscape has remained largely implicit. In this paper, I wish to explore more explicitly the connection of boundaries, belonging and landscapes by thinking about how landscapes become spatially bounded scenes that visually communicate what belongs and what does not. My focus is on understanding how landscapes are, in part, constructed through a territorialized politics of belonging-the discourses and practices that establish and maintain discursive and material boundaries that correspond to the imagined geographies of a polity and to the spaces that normatively embody the polity. To explore this relationship, I consider a controversy surrounding the operation of a slaughterhouse in Hugo, Minnesota, which was used extensively for Ua Dab-a Hmong tradition of ritual animal sacrifice. The discourses and practices surrounding efforts to remove the slaughterhouse from Hugo, on the one hand, and to have it remain in Hugo, on the other, offer a case through which to explore the politics of belonging and the boundaries that this creates in constructing landscapes.
Intensity-Modulated Radiotherapy in the Standard Management of Head and Neck Cancer: Promises and Pitfalls
Authors: Mendenhall William M. , Amdur Robert J. , Palta Jatinder R.
Published: June 2006

The purpose of this article is to review the role of intensity-modulated radiotherapy (IMRT) in the standard management of patients with head and neck cancer through a critical review of the pertinent literature. IMRT may result in a dose distribution that is more conformal than that achieved with three-dimensional conformal radiotherapy (3D CRT), allowing dose reduction to normal structures and thus decreasing toxicity and possibly enhancing locoregional control through dose escalation. Disadvantages associated with IMRT include increased risk of a marginal miss, decreased dose homogeneity, increased total body dose, and increased labor and expense. Outcomes data after IMRT are limited, and follow-up is relatively short. Locoregional control rates appear to be comparable to those achieved with 3D CRT and, depending on the location and extent of the tumor, late toxicity may be lower. Despite limited data on clinical outcomes, IMRT has been widely adopted as a standard technique in routine practice and clinical trials. The use of IMRT involves a learning curve for the practitioner and will continue to evolve, requiring continuing education and monitoring of outcomes from routine practice. Additional standards pertaining to a variety of issues, including target definitions and dose specification, need to be developed. Phase III trials will better define the role of IMRT in coming years.
Adjuvant Therapy in Patients With Resected Poor-Risk Head and Neck Cancer
Authors: Bernier Jacques , Vermorken Jan B. , Koch Wayne M.
Published: June 2006

In patients with locally or regionally advanced head and neck carcinomas, postoperative radiotherapy has historically been the adjuvant therapy applied for patients with prognostically worrisome pathologic features. Any improvement in therapeutic index achieved by adding cytotoxic agents to postoperative radiotherapy remained controversial. However, two recent randomized trials, conducted in parallel in Europe and the United States, produced level I evidence regarding improved efficacy in this setting for the concurrent administration of chemotherapy and radiotherapy. High-dose cisplatin and irradiation can now be considered the standard therapeutic approach for resected poor-risk disease. The presence of positive margins and/or nodal extracapsular spread in the surgical specimens are the subgroups that appear to benefit in the most significant way from the addition of chemotherapy to radiation. Many questions regarding the optimization of adjuvant treatments still remain unanswered, especially with respect to improvement of patient compliance, integration of novel drugs targeting both locoregional and systemic control, and modulation of treatment intensity according to risk levels.
Prevention and Treatment of Dysphagia and Aspiration After Chemoradiation for Head and Neck Cancer
Authors: Rosenthal David I. , Lewin Jan S. , Eisbruch Avraham
Published: June 2006

Safe, successful swallowing depends on complex events affected by head and neck cancers and their treatment. This article reviews the swallowing process, how it is affected by chemoradiotherapy, and the evaluation, prevention, and treatment of swallowing disorders. Specific recommendations are made to promote maintenance and recovery of swallowing function.
Neverland is an evolutionally conserved Rieske-domain protein that is essential for ecdysone synthesis and insect growth
Authors: Yoshiyama Takuji , Namiki Toshiki , Mita Kazuei , Kataoka Hiroshi , Niwa Ryusuke
Published: June 2006

Steroid hormones mediate a wide variety of developmental and physiological events in multicellular organisms. During larval and pupal stages of insects,the principal steroid hormone is ecdysone, which is synthesized in the prothoracic gland (PG) and plays a central role in the control of development. Although many studies have revealed the biochemical features of ecdysone synthesis in the PG, many aspects of this pathway have remained unclear at the molecular level. We describe the neverland (nvd) gene, which encodes an oxygenase-like protein with a Rieske electron carrier domain, from the silkworm Bombyx mori and the fruitfly Drosophila melanogaster. nvd is expressed specifically in tissues that synthesize ecdysone, such as the PG. We also show that loss of nvd function in the PG causes arrest of both molting and growth during Drosophiladevelopment. Furthermore, the phenotype is rescued by application of 20-hydroxyecdysone or the precursor 7-dehydrocholesterol. Given that the nvd family is evolutionally conserved, these results suggest that Nvd is an essential regulator of cholesterol metabolism or trafficking in steroid synthesis across animal phyla.
Targeting of the tail-anchored peroxisomal membrane proteins PEX26 and PEX15 occurs through C-terminal PEX19-binding sites
Authors: Halbach A. , Landgraf C. , Lorenzen S. , Rosenkranz K. , Volkmer-Engert R. , Erdmann R. , Rottensteiner H.
Published: June 2006

Tail-anchored proteins contain a single transmembrane domain (TMD) followed by a short C-terminal domain extending into the organellar lumen. Tail-anchored proteins are thought to target to the correct subcellular compartment by virtue of general physicochemical properties of their C-termini; however, the machineries that enable correct sorting remain largely elusive. Here we analyzed targeting of the human peroxisomal tail-anchored protein PEX26. Its C-terminal-targeting signal contains two binding sites for PEX19, the import receptor for several peroxisomal membrane proteins. One PEX19-binding site overlapped with the TMD, the other was contained within the luminal domain. Although the PEX19-binding site containing the TMD targeted to peroxisomes to some extent, the luminal site proved essential for correct targeting of the full-length protein, as it prevented PEX26 from mislocalization to mitochondria. Its function as a targeting motif was proved by its ability to insert a heterologous TMD-containing fragment into the peroxisomal membrane. Finally we show that PEX19 is essential for PEX26 import. Analysis of the yeast tail-anchored protein Pex15p revealed that it also harbors a luminal PEX19-binding site that acts as a peroxisomal-targeting motif. We conclude that C-terminal PEX19-binding sites mark tail-anchored proteins for delivery to peroxisomes.
Wedding in Galilee (Urs al-jalil)
Authors: KENNEDY TIM
Published: June 2006

ABSTRACT Michel Khleifi's Wedding in Galilee continues to astound, nearly 20 years after release, with its clear-sighted analysis of the forces constraining the development of Palestinian society. Transcending dogma, the film calls for internal change and for space in which the people may advance their rights for self-determination and the creation of a Palestinian state.
On Solon's Land Reform
Authors: Németh György
Published: June 2006

The land-law of Solon can be divided into two parts: on the one hand it
is a seisachtheia (the shaking off of burdens), which is the extracting
of border-stones in the “serving land” (and has nothing to do with
indebtedness), and on theother hand it is
therepurchase of citizens who had been unlawfully sold abroad. The
legal status of the social class called hektemoroi was similar to that
of the helots in Sparta and the penestai in Thessaly. The hektemoroi
were liberated by the reform of Solon, thus they become thetes, i.e.
lawful citizens. This measure was taken much rather in favour of the big
landowners than of the hektemoroi. The latter could not get their former
lands, since the lands were usually taken by aristocrats to grow exportable
olive and grapevine. (It wasonly the export
of cornthat was forbidden by Solon.) Raising the thetes to the rank of
citizens became the most important element of the Athenian development. (At
this point the economicmodels of Athens,
Sparta, Thessaly and Crete diverge.) The social class of the thetes
gave Athens not only a supply for agricultural labour but also the masses of
craftsmen and shipmen, who served the city even as oarsmen while it was
becoming a great power…
Problems of the Augment in Vedic
Authors: Ittzés Máté
Published: June 2006

The paper deals with two questions of the Vedic augment. Firstly, the
Vedic forms with an apparently long syllabic augment are re-examined and the
conclusion is drawn that these forms are due to phonological and analogical
processes and do not form evidence in favour of an original long variant of the
syllabic augment. Secondly, the temporal augment of vowel-initial roots is
considered, which consists of the vrddhi of the initial vowel. An important
analogical support for this general Old Indian rule is pointed out, namely the
influence of those verbal stems that began with *Hei-, *Heu- or *Her-
and had full or lengthened grade roots in the preterit tenses and therefore had
phonetically regular vrddhi vowels in their augmented forms.
Translating Foreign Otherness
Authors: Yifeng Sun
Published: June 2006

Central to translation is cultural anxiety and ambivalence about foreign otherness, which is essentially reified in cultural politics underlying translation. The ubiquity of ideology may be exaggerated or overstated, but it is manifest in a tendency to be seen as primarily bound up with language and art, and the needs of translation are inseparable from the political or cultural concerns in the target language system. The cultural politics of difference has a lot to do with truth-telling, sincerity, intelligibility and empathy. Effective translation depends not only upon a reasonable understanding of the content of the message that has been translated, but also on an ability, on the part of the target reader, to relate that message to the relevant cultural situation by developing a necessary knowledge of foreign otherness in its cultural political context. The artifice or artificiality of sameness entails turning away and reduction, yet cultural impositions are understandably considered as intrusive, and debates on literature and translation, often ideologically charged, tend to center around what foreign otherness is capable of doing or undoing. In defiance of the prevailing political conditions, translation may embrace and introduce foreign political and ethical values.
Conference Reports
Authors: Chesterman Andrew , Mullamaa Kristina , Orenstein Jill , Pavlovic Nataša
Published: June 2006

“The Study of Language
and Translation”, Hogeschool Gent, School of Translation Studies-Belgium, Gent, 12-14 January 2006; “New Research
in Translation and Interpreting Studies”, Intercultural Studies Group,
Universitat Rovira i Virgili-
Spain Tarragona, 7-8 October 2005