bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of Wood Wettability by the Wilhelmy Method. Part 2. Determination of Apparent Contact Angles
Authors: Wålinder M.E.P. , Ström G.
Published: March 2005

This work focuses on the determination of apparent contact angles on wood by the Wilhelmy method.
In this method, the force acting on an object is measured during a test cycle involving immersion in and
withdrawal from a probe liquid. Fresh and aged veneers of extracted and non-extracted heart- and sapwood
of pine were investigated. The results indicate that wicking of the probe liquids, into and along the
porous wood veneers, occurs during the test cycles and that this strongly affects the determination of
contact angles. It is suggested that two different wicking phenomena occur. First, when the veneer contacts
the liquid, an instantaneous ‘initial wicking’ occurs. It is suggested that this initial wicking is influenced
primarily by the liquid density and structural properties of the specimen (such as porosity and surface
roughness), and not by surface energetics. An initial wicking constant was therefore estimated for
the different veneer samples based on measurements in octane. Second, after the initial wicking, a continuing
‘secondary wicking’ is observed. In some cases, this may result in zero contact angle after a certain
immersion depth. Contact angles should, therefore, be estimated from the initial part of the immersion,
where the secondary wicking can be neglected. This may also reduce any contamination of the
probe liquids by extractives. The Wilhelmy method seems to be a valuable tool for estimating the wetting
properties of wood, permitting reproducible measurements of apparent contact angles provided that
there is efficient control of wicking and contamination effects.
Acid-Sensing Properties in Rat Gastric Sensory Neurons from Normal and Ulcerated Stomach
Authors: Sugiura Takeshi , Dang Khoa , Lamb Kenneth , Bielefeldt Klaus , Gebhart G. F.
Published: March 2005

Gastric acid contributes to dyspeptic symptoms, including abdominal pain, in patients with disorders of the proximal gastrointestinal tract. To examine the molecular sensor(s) of gastric acid chemonociception, we characterized acid-elicited currents in dorsal root ganglion (DRG) and nodose ganglion (NG) neurons that innervate the stomach and examined their modulation after induction of gastric ulcers. A fluorescent dye (DiI) was injected into the stomach wall to retrogradely label gastric sensory neurons. After 1-2 weeks, gastric ulcers were induced by 45 s of luminal exposure of the stomach to 60% acetic acid injected into a clamped area of the distal stomach; control animals received saline. In whole-cell voltage-clamp recordings, all gastric DRG neurons and 55% of NG neurons exhibited transient, amiloride-sensitive, acid-sensing ion-channel (ASIC) currents. In the remaining 45% of NG neurons, protons activated a slow, sustained current that was attenuated by the transient receptor potential vanilloid subtype 1 antagonist, capsazepine. The kinetics and proton sensitivity of amiloride-sensitive ASIC currents differed between NG and DRG neurons. NG neurons had a lower proton sensitivity and faster kinetics, suggesting expression of specific subtypes of ASICs in the vagal and splanchnic innervation of the stomach. Effects of Zn2+andN,N,N′,N′-tetrakis-(2-pyridylmethyl)-ethylenediamine on acid-elicited currents suggest contributions of ASIC1a and ASIC2a subunits. Gastric ulcers altered the properties of acid-elicited currents by increasing pH sensitivity and current density and changing current kinetics in gastric DRG neurons. The distinct properties of NG and DRG neurons and their modulation after injury suggest differential contributions of vagal and spinal afferent neurons to chemosensation and chemonociception.
Frontal Networks for Learning and Executing Arbitrary Stimulus-Response Associations
Authors: Boettiger Charlotte A. , D'Esposito Mark
Published: March 2005

Flexible rule learning, a behavior with obvious adaptive value, is known to depend on an intact prefrontal cortex (PFC). One simple, yet powerful, form of such learning consists of forming arbitrary stimulus-response (S-R) associations. A variety of evidence from monkey and human studies suggests that the PFC plays an important role in both forming new S-R associations and in using learned rules to select the contextually appropriate response to a particular stimulus cue. Although monkey lesion studies more strongly implicate the ventrolateral PFC (vlPFC) in S-R learning, clinical data and neurophysiology studies have implicated both the vlPFC and the dorsolateral region (dlPFC) in associative rule learning. Previous human imaging studies of S-R learning tasks, however, have not demonstrated involvement of the dlPFC. This may be because of the design of previous imaging studies, which used few stimuli and used explicitly stated one-to-one S-R mapping rules that were usually practiced before scanning. Humans learn these rules very quickly, limiting the ability of imaging techniques to capture activity related to rule acquisition. To address these issues, we performed functional magnetic resonance imaging while subjects learned by trial and error to associate sets of abstract visual stimuli with arbitrary manual responses. Successful learning of this task required discernment of a categorical type of S-R rule in a block design expected to yield sustained rule representation. Our results show that distinct components of the dorsolateral, ventrolateral, and anterior PFC, lateral premotor cortex, supplementary motor area, and the striatum are involved in learning versus executing categorical S-R rules.
The Scaffold Protein Homer1b/c Links Metabotropic Glutamate Receptor 5 to Extracellular Signal-Regulated Protein Kinase Cascades in Neurons
Authors: Mao Limin , Yang Lu , Tang Qingsong , Samdani Shazia , Zhang Guochi , Wang John Q.
Published: March 2005

Group I metabotropic glutamate receptors (mGluRs) increase cellular levels of inositol-1,4,5-triphosphate (IP3) and thereby trigger intracellular Ca2+release. Also, group I mGluRs are organized with members of Homer scaffold proteins into multiprotein complexes involved in postreceptor signaling. In this study, we investigated the relative importance of the IP3/Ca2+signaling and novel Homer proteins in group I mGluR-mediated activation of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) in cultured rat striatal neurons. We found that selective activation of mGluR5, but not mGluR1, increased ERK1/2 phosphorylation. Whereas the IP3/Ca2+cascade transmits a small portion of signals from mGluR5 to ERK1/2, the member of Homer family Homer1b/c forms a central signaling pathway linking mGluR5 to ERK1/2 in a Ca2+-independent manner. This was demonstrated by the findings that the mGluR5-mediated ERK1/2 phosphorylation was mostly reduced by a cell-permeable Tat-fusion peptide that selectively disrupted the interaction of mGluR5 with the Homer1b/c and by small interfering RNAs that selectively knocked down cellular levels of Homer1b/c proteins. Furthermore, ERK1/2, when only coactivated by both IP3/Ca2+- and Homer1b/c-dependent pathways, showed the ability to phosphorylate two transcription factors, Elk-1 and cAMP response element-binding protein, and thereby facilitated c-Fos expression. Together, we have identified two coordinated signaling pathways (a conventional IP3/Ca2+vs a novel Homer pathway) that differentially mediate the mGluR5-ERK coupling in neurons. Both the Ca2+-dependent and -independent pathways are corequired to activate ERK1/2 to a level sufficient to achieve the mGluR5-dependent synapse-to-nucleus communication imperative for the transcriptional regulation.
Schwingungsmessung und -analyse mit Digital-Shearografie (Vibration Measurement and Analysis using Digital Shearography)
Authors: Steinchen Wolfgang , Gan Yimin , Kupfer Gerhard , Mäckel Peter
Published: March 2005

Eine der effektivsten Anwendungen der shearografischen Interferometrie ist die Ermittlung, Sichtbarmachung und Messung mechanischer Schwingungen von undurchsichtigen Objekten. Dafür wird als häufigste Methode die Zeitmittelungs-Shearografie zur zerstörungsfreien Prüfung (NDT) und qualitativen Schwingungsanalyse eingesetzt. Der Amplitudengradient kann durch die Änderung des Shearabstandes bestimmt werden. Die Streifen, die bei sinusförmiger Schwingung durch die Zeitmittelungs-Shearografie aufgezeichnet werden, werden durch die Besselfunktion J0
2 beschrieben. Etwas verschwommene Streifen auf der Oberfläche des schwingenden Objekts werden nach einer FFT-Filterung klarer. Die zahlenmäßige Auswertung von Schwingungen erfordert eine genauere Analyse. Für die Bestimmung der relativen Schwingungsphase und -amplitude in jedem Punkt der Objektoberfläche wird eine stroboskopische Methode eingesetzt, wofür allerdings ein komplexerer optischer Aufbau und eine passende Software nötig sind. Allerdings ist die Aufzeichnung von harmonischen Schwingungen mittels Doppel-Puls-Laser [1; 2] technisch noch aufwändiger und kostenintensiver.
In Search of Deeper Identities Neopaganism and "Native Faith" in Contemporary Ukraine
Authors: Ivakhiv Adrian
Published: March 2005

This article examines the growth of Neopaganism and Native Faith in post-Soviet Ukraine. It traces the historical development of Neopagan ideas and contextualizes their emergence within the cultic milieus of alternative religion and ethnic nationalism. It surveys the main contemporary Ukrainian Neopagan and Native Faith groups and movements, assessing their future growth possibilities and comparing them with more familiar forms of Western Neopaganism. The author argues that these Ukrainian movements have become caught up within a set of ideas which are ideologically right-wing and scientifically insupportable, but that this represents a phase of development comparable to an earlier phase of Anglo-American Neopaganism, at least in its reliance on "alternative" scholarship and on a strong form of "identity politics." Like those Western movements, Ukrainian Native Faith might overcome its present-day limitations, but this will be difficult as long as the country continues to face the economic and political struggles within which it has recently been mired.
Reconstructing the behaviors of extinct species: An excursion into comparative paleoneurology
Authors: Rogers Scott W.
Published: March 2005

How can the behavior of an extinct species be reconstructed—say a dinosaur such as Allosaurus? Despite the relatively abundant fossilized remains of this and other dinosaurs, the incompleteness of the fossil record has permitted room for considerable speculation, mythology, and perhaps a bit of unsettling reflection on what factors contributed to the eventual fate of these remarkably successful animals. Among the speculations is how these ‘bigger‐than‐life’ creatures behaved, a topic that itself can attain equal diversity and grandeur. With recent advancements in measuring the relatedness of living organisms, how genetics contribute to brain development and how this relates to behavior, combined with the availability of newly discovered high quality fossils and imaging methods to exploit their secrets, novel insights into how extinct creatures such as Allosaurus intermingled with its many relatives over 100 million years ago are beginning to emerge. © 2005 Wiley‐Liss, Inc.
Rectorite/thermoplastic polyurethane nanocomposites. II. Improvement of thermal and oil‐resistant properties
Authors: Ma Xiaoyan , Lu Haijun , Lian Guozhengg , Zhao Jingchan , Lu Tingli
Published: March 2005

Organ‐rectorite/thermoplastic polyurethane (OREC/TPUR) nanocomposites were synthesized via melt intercalation. The dynamic mechanical properties by dynamic mechanical analysis (DMA), thermal and oil‐resistant properties were investigated. The results show that the storage modulus (E′), loss modulus (E″), and glass‐transition temperature (Tg) of the nanocomposites have an increase to some extent than those of pure TPUR. The thermal stability of nanocomposites was also studied in detail by thermal gravity analysis (TGA), which was higher than that of pristine TPUR matrix when the content of organic REC is at 2 wt %, and the decomposition temperature at 10% weight loss of OREC/TPUR is greatly increased up to 330°C from 315°C. Oil uptake of the composites is also significantly reduced in comparison with TPUR matrix, which is ascribed to the good barrier effect of nanosheets of OREC. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1165–1169, 2005
Mechanical properties and applications for floor tiles of a composite from clay and maleated polyethylene
Authors: Otsuki Toshi , Qiu Wulin , Hirotsu Takahiro
Published: March 2005

New composites were prepared from dried waste mud containing clay (Clay) and maleated polyethylene (MPE) by melt mixing. Scanning electron microscopy showed strong adhesion of MPE to Clay in the MPE–Clay composite, and this was probably due to the increased compatibility between MPE and Clay. With an increase in the Clay concentration to 60 wt %, the tensile strength of the MPE–Clay composite increased. Furthermore, the smaller elongation of the MPE–Clay composite indicated effective transfer of the high tensile strength of Clay to the MPE matrix through the strong adhesion between Clay and MPE. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1176–1182, 2005
Fabrication of calcium sulfate/PLLA composite for bone repair
Authors: Gao Chunjuan , Gao Jianping , You Xiudong , Huo Shujuan , Li Xiulan , Zhang Yang , Zhang Wenhai
Published: March 2005

The bone‐repairing composite material CS/PLLA was fabricated by mixing poly‐L‐lactic acid (PLLA) and calcium sulfate hemihydrate (CSH). The structure of the composite was analyzed with Infrared spectroscope, X‐ray diffraction, and scanning electron microscope. The results indicated that the crystal pattern of calcium sulfate was affected by the addition of PLLA. PLLA part impacted the development of calcium sulfate dihydrate (CSD) crystal by slowing the conversion from CSH to CSD, so the composites are actually composed of CSH, CSD, and PLLA. The absorbing test in vitro showed that CS/PLLA composite absorbed more slowly than pure CS, suggesting the addition of PLLA can adjust the absorption rate of CS to meet different requirements. The pH value changes of the media had similar trends for different composites during the absorbing test of CS/PLLA samples in aqueous medium, which was connected to the absorption of calcium sulfate. The absorption of calcium sulfate in a certain time left a porous PLLA scaffold that will enable cells to further grow in. The surface of CS/PLLA pellets was inoculated with human osteoblasts, and the primary results showed that the osteoblasts could attach and spread on the surface, which will stimulate our desire for further study. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 73A: 244–253, 2005
Large quartic groups on translation planes, II—Even order: Characterization of the Ott‐Schaeffer planes
Authors: Biliotti Mauro , Jha Vikram , Johnson Norman L.
Published: March 2005

A general theory of collineation groups generated by quartic groups of even order is considered. Applications are given to collineation groups generated by ‘large’ quartic groups. © 2005 Wiley Periodicals, Inc. J Combin Designs 13: 195–210, 2005.
Improved mass transfer and biodegradation rates of naphthalene particles using a novel bead mill bioreactor
Authors: Riess Ryan , Nemati Mehdi , Headley John , Hill Gordon
Published: March 2005

One of the main challenges in the treatment of polycyclic aromatic hydrocarbons (PAHs) in controlled bioreactors is the hydrophobicity and low solubility of these compounds in the aqueous phase, resulting in appreciable mass transfer limitations within the bioreactor. To address this challenge, we have developed a modified roller bioreactor (Bead Mill Bioreactor) in which inert particles are used to improve mass transfer from the solid phase to the aqueous phase. Experimental results with naphthalene as a model PAH and Pseudomonas putida as a candidate bacterium indicate that both the mass transfer rate from the solid phase to liquid phase and the biodegradation rate in the Bead Mill Bioreactor (BMB) were significantly higher than those in a conventional roller bioreactor (20‐fold and 5.5‐fold, respectively). The enhancement of mass transfer was dependent on the type, size and volumetric loading of the inert particles, as well as concentration of particulate naphthalene. The highest mass transfer coefficient (kLa = 2.1 h−1) was achieved with 3 mm glass beads at a volumetric loading of 50% (particle volume/working volume) with 10 000 mg dm−3 particulate naphthalene. The maximum biodegradation rate of naphthalene attained in the bead mill bioreactor (59.2 mg dm−3 h−1 based on the working volume and 118.4 mg dm−3 h−1 based on the liquid volume) surpasses most other rates published in the literature and is equivalent to values reported for more complex bioreaction systems. The bead mill bioreactor developed in the present work not only enjoys a simple design but shows excellent performance for treatment of PAHs suspended in an aqueous phase. This fundamental information will be of significant value for future studies involving soil‐bound PAHs. Copyright © 2005 Society of Chemical Industry
Catalytic reduction of N2O with CH4 and C3H6 over Ag–Rh/Al2O3 bimetallic catalyst in the presence of oxygen
Authors: Tzitzios VK , Georgakilas V , Angelidis TN
Published: March 2005

A study of nitrous oxide (N2O) reduction with methane (CH4) and propene (C3H6) in the presence of oxygen (5%) over Ag/Al2O3, Rh/Al2O3 and Ag–Rh/Al2O3 catalysts, with Ag and Rh loadings of 5 wt% and 0.05 wt% respectively, has been performed. From the results, it was observed that the Ag–Rh bimetallic catalyst was the most active for both nitrous oxide removal (more than 95%) and hydrocarbon oxidation. This high activity seems to be connected with a synergistic effect between Ag and Rh. The findings from X‐ray diffraction and X‐ray photoelectron spectroscopy studies showed also, that there were no strong interactions (eg alloying) between Ag and Rh. Copyright © 2005 Society of Chemical Industry
Multiple small doses of levodopa plus entacapone produce continuous dopaminergic stimulation and reduce dyskinesia induction in MPTP‐treated drug‐naïve primates
Authors: Smith Lance A. , Jackson Michael J. , Al‐Barghouthy Ghassan , Rose Sarah , Kuoppamaki Mikko , Olanow C. Warren , Jenner Peter
Published: March 2005

The original article to which this Erratum refers has been published in Movement Disorders 2005;20(3)306–314.
Chaotic analog associative memory
Authors: Imai Hisao , Osana Yuko , Hagiwara Masafumi
Published: March 2005

This paper proposes chaotic analog associative memory (CAAM), which can handle one‐to‐many learning pairs composed of analog patterns. Most past associative memory models have considered a binary pattern as the pattern to be learned, which makes it difficult to handle analog patterns. It is also a problem that the superposed pattern is recalled due to interaction between the memorized patterns. Thus, it becomes difficult to handle the association of one‐to‐many learning pairs, in which multiple patterns can be recalled from a single given pattern. In contrast, the proposed model uses a multiwinner self‐organizing neural network (MWSONN), which can handle analog patterns, and realizes association of the analog patterns. In the proposed CAAM, the chaotic neuron is introduced as a part of the network, and one‐to‐many association is realized by utilizing the dynamic recall power of the chaotic neuron. Computer experiments verify that the association of one‐to‐many learning pairs composed of analog patterns can be realized, and that the proposed model has high noise immunity and robustness to faults. © 2005 Wiley Periodicals, Inc. Syst Comp Jpn, 36(4): 82–90, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10325
Application of the µPlangent intelligent mobile agent architecture for embedded systems to the inspection of power systems
Authors: Cho Kenta , Irie Yutaka , Ohsuga Akihiko , Sekiguchi Katsuhiko , Honiden Shinichi
Published: March 2005

This paper presents a patrol agent for power systems based on the µPlangent intelligent mobile architecture operating on embedded devices. µPlangent is an architecture featuring intelligent autonomous operation on embedded systems with poor resources. The patrol agent offers flexible operation such as acquisition of related data in case of a fault. © 2005 Wiley Periodicals, Inc. Syst Comp Jpn, 36(4): 60–70, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10352
Impact of the 1994 Northridge earthquake on the art and practice of structural engineering
Authors: Naeim Farzad
Published: March 2005

The 1994 Northridge earthquake has impacted structural engineering practice in several very important ways. Since then we have learned to avoid unjustified extrapolations, we have recognized to value and promote seismic instrumentation, we have improved our codes and guidelines and at the same time created a maze of various codes and standards which are confusing at best, and we have started our long journey along the road of performance‐based seismic engineering. This paper provides an overview of the impacts of the 1994 Northridge earthquake on the art and practice of structural engineering. Copyright © 2004 John Wiley & Sons, Ltd.
Automatic 1D inversion of multifrequency airborne electromagnetic data with artificial neural networks: discussion and a case study
Authors: Ahl Andreas
Published: March 2005

Artificial neural networks were used to implement an automatic inversion of frequency‐domain airborne electromagnetic (AEM) data that do not require a priori information about the survey area. Two classes of model, i.e. homogeneous half‐space models and horizontally layered half‐space models with two layers, are used in this 1D inversion, and for each data point the selection of the class of 1D model is performed prior to the inversion, also using an artificial neural network. The proposed inversion method was tested in a survey area situated in Austria, northwest of Vienna in the Bohemian Massif. The results of the inversion were compared with the geological setting, logging results, and seismic and gravimetric measurements. This comparison shows a good correlation between the AEM models and the known geological and geophysical data.
Expression of mitochondrial HMGCoA synthase and glutaminase in the colonic mucosa is modulated by bacterial species
Authors: Cherbuy Claire , Andrieux Claude , Honvo‐Houeto Edith , Thomas Muriel , Ide Catherine , Druesne Nathalie , Chaumontet Catherine , Darcy‐Vrillon Béatrice , Duée Pierre‐Henri
Published: March 2005

The expression of the colonic mitochondrial 3‐hydroxy 3‐methyl glutaryl CoA (mHMGCoA) synthase, a key control site of ketogenesis from butyrate, is lower in germ‐free (GF) than in conventional (CV) rats. In contrast, the activity of glutaminase is higher. The objective of this study was to investigate whether the intestinal flora can affect gene expression through short chain fatty acid (SCFA) and butyrate production. GF rats were inoculated with a conventional flora (Ino‐CV) or with a bacterial strain producing butyrate (Clostridium paraputrificum, Ino‐Cp) or not (Bifidobacterium breve, Ino‐Bb). In the Ino‐CV rats, mHMGCoA synthase expression was restored to the CV values 2 days after the inoculation, i.e. concomitantly with SCFA production. In the Ino‐Cp group, but not in the Ino‐Bb group, mHMGCoA synthase and glutaminase were expressed at the level observed in the CV rats. These data suggest that the intestinal flora, through butyrate production, could control the expression of colonic mHMGCoA synthase and glutaminase. These modifications in gene expression by butyrate in vivo seem unrelated to a modification of histone acetylation.
The effect of mutations surrounding and within the active site on the catalytic activity of ricin A chain
Authors: Marsden Catherine J. , Fülöp Vilmos , Day Philip J. , Lord J. Michael
Published: March 2005

Models for the binding of the sarcin–ricin loop (SRL) of 28S ribosomal RNA to ricin A chain (RTA) suggest that several surface exposed arginine residues surrounding the active site cleft make important interactions with the RNA substrate. The data presented in this study suggest differing roles for these arginyl residues. Substitution of Arg48 or Arg213 with Ala lowered the activity of RTA 10‐fold. Furthermore, substitution of Arg213 with Asp lowered the activity of RTA 100‐fold. The crystal structure of this RTA variant showed it to have an unaltered tertiary structure, suggesting that the positively charged state of Arg213 is crucial for activity. Substitution of Arg258 with Ala had no effect on activity, although substitution with Asp lowered activity 10‐fold. Substitution of Arg134 prevented expression of folded protein, suggesting a structural role for this residue. Several models have been proposed for the binding of the SRL to the active site of RTA in which the principal difference lies in the conformation of the second ‘G’ in the target GAGA motif in the 28S rRNA substrate. In one model, the sidechain of Asn122 is proposed to make interactions with this G, whereas another model proposes interactions with Asp75 and Asn78. Site‐directed mutagenesis of these residues of RTA favours the first of these models, as substitution of Asn78 with Ser yielded an RTA variant whose activity was essentially wild‐type, whereas substitution of Asn122 reduced activity 37.5‐fold. Substitution of Asp75 failed to yield significant folded protein, suggesting a structural role for this residue.
UV‐A/blue‐light inactivation of the ‘metal‐free’ hydrogenase (Hmd) from methanogenic archaea
Authors: Lyon Erica J. , Shima Seigo , Buurman Gerrit , Chowdhuri Shantanu , Batschauer Alfred , Steinbach Klaus , Thauer Rudolf K.
Published: March 2005

H2‐forming methylenetetrahydromethanopterin dehydrogenase (Hmd) is an unusual hydrogenase present in many methanogenic archaea. The homodimeric enzyme dubbed ‘metal‐free’ hydrogenase does not contain iron–sulfur clusters or nickel and thus differs from [Ni‐Fe] and [Fe‐Fe] hydrogenases, which are all iron–sulfur proteins. Hmd preparations were found to contain up to 1 mol iron per 40 kDa subunit, but the iron was considered to be a contaminant as none of the catalytic and spectroscopic properties of the enzyme indicated that it was an essential component. Hmd does, however, harbour a low molecular mass cofactor of yet unknown structure. We report here that the iron found in Hmd is most probably functional after all. Further investigation was initiated by the discovery that Hmd is inactivated upon exposure to UV‐A (320–400 nm) or blue‐light (400–500 nm). Enzyme purified in the dark exhibited an absorption spectrum with a maximum at approximately 360 nm and which mirrored its sensitivity towards light. In UV‐A/blue‐light the enzyme was bleached. The cofactor extracted from active Hmd was also light sensitive. It showed an UV/visible spectrum similar to that of the active enzyme and was bleached upon exposure to light. Photobleached cofactor no longer had the ability to reconstitute active Hmd from the apoenzyme. When purified in the dark, Hmd consistently contained per monomer about one Fe, which was tightly bound to the cofactor. The iron was released from the enzyme and from the cofactor upon light inactivation. Hmd activity was inhibited by high concentrations of CO and CO protected the enzyme from light inactivation indicating that the iron in Hmd is of functional importance. Therefore, reference to Hmd as ‘metal‐free’ hydrogenase is no longer appropriate.
Effect of the valence electron concentration on the bulk modulus and chemical bonding in Ta2AC and Zr2AC (A=Al, Si, and P)
Authors: Schneider Jochen M. , Music Denis , Sun Zhimei
Published: March 2005

We have studied the effect of the valence electron concentration, on the bulk modulus and the chemical bonding in Ta2AC and Zr2AC (A=Al, Si, and P) by means of ab initio calculations. Our equilibrium volume and the hexagonal ratio (c∕a) agree well (within 2.7% and 1.2%, respectively) with previously published experimental data for Ta2AlC. The bulk moduli of both Ta2AC and Zr2AC increase as Al is substituted with Si and P by 13.1% and 20.1%, respectively. This can be understood since the substitution is associated with an increased valence electron concentration, resulting in band filling and an extensive increase in cohesion.
Inverted velocity profiles in rarefied cylindrical Couette gas flow and the impact of the accommodation coefficient
Authors: Yuhong Sun , Barber Robert W. , Emerson David R.
Published: March 2005

Cylindrical Couette gas flow in the noncontinuum regime has been investigated using the boundary treatment derived from Maxwell’s slip-flow model. It is shown that the tangential momentum accommodation coefficient plays an important role in determining the predicted velocity profile. The present analysis is in close agreement with previous analytical studies and shows good qualitative agreement with available direct simulation Monte Carlo data. The results predict the presence of an inverted velocity profile for the case where the inner cylinder rotates and the outer cylinder is stationary. However, our analysis further shows that the phenomenon of velocity inversion is only dependent on the accommodation coefficient of the outer cylinder. From the analysis, we derive specific criteria for the accommodation coefficient of the outer cylinder under which (i) no velocity inversion will take place, (ii) a partially inverted velocity profile will be observed, and (iii) a fully inverted velocity profile will be present. In contrast, when the outer cylinder rotates and the inner cylinder is stationary, it is shown that velocity inversion does not occur.
Influence of the oxygen concentration of atomic-layer-deposited HfO2 films on the dielectric property and interface trap density
Authors: Park Jaehoo , Cho Moonju , Kim Seong Keun , Park Tae Joo , Lee Suk Woo , Hong Sug Hun , Hwang Cheol Seong
Published: March 2005

The influence of the ozone concentration (160–370g∕m3) during atomic layer deposition of HfO2-gate dielectrics on the dielectric performance of the films grown on Si was studied. Although ozone was effective in reducing the impurity concentration in the film compared to H2O, the higher concentration slightly deteriorated the dielectric performance. More importantly, the degradation in the interface trap property with increasing post-annealing temperature became more serious as the ozone concentration increased. Investigation of the interface states using x-ray photoelectron spectroscopy revealed that the excessive oxygen incorporated during the film growth made the interfacial sub-oxide species (SiO, Si2O3, and silicate) and SiO2 coordinate more with oxygen. This increased the interface trap density and degraded the interface properties.
Activation of pausing F
1
motor by external force
Authors: Hirono-Hara Yoko , Ishizuka Koji , Kinosita Kazuhiko , Yoshida Masasuke , Noji Hiroyuki
Published: March 2005

A rotary motor F
1
, a catalytic part of ATP synthase, makes a 120° step rotation driven by hydrolysis of one ATP, which consists of 80° and 40° substeps initiated by ATP binding and probably by ADP and/or P
i
dissociation, respectively. During active rotations, F
1
spontaneously fails in ADP release and pauses after a 80° substep, which is called the ADP-inhibited form. In the present work, we found that, when pushed >+40° with magnetic tweezers, the pausing F
1
resumes its active rotation after releasing inhibitory ADP. The rate constant of the mechanical activation exponentially increased with the pushed angle, implying that F
1
weakens the affinity of its catalytic site for ADP as the angle goes forward. This finding explains not only its unidirectional nature of rotation, but also its physiological function in ATP synthesis; it would readily bind ADP from solution when rotated backward by an F
o
motor in the ATP synthase. Furthermore, the mechanical work for the forced rotation was efficiently converted into work for expelling ADP from the catalytic site, supporting the tight coupling between the rotation and catalytic event.
Biosynthesis of a D-amino acid in peptide linkage by an enzyme from frog skin secretions
Authors: Jilek Alexander , Mollay Christa , Tippelt Christa , Grassi Jacques , Mignogna Giuseppina , Müllegger Johannes , Sander Veronika , Fehrer Christine , Barra Donatella , Kreil Günther
Published: March 2005

d-amino acids are present in some peptides from amphibian skin. These residues are derived from the correspondingl-amino acids present in the respective precursors. From skin secretions ofBombinae, we have isolated an enzyme that catalyzes the isomerization of anl-Ile in position 2 of a model peptide tod-allo-Ile. In the course of this reaction, which proceeds without the addition of a cofactor, radioactivity from tritiated water is incorporated into the second position of the product. The amino acid sequence of this isomerase could be deduced from cloned cDNA and genomic DNA. After expression of this cDNA in oocytes ofXenopus laevis, isomerase activity could be detected. Polypeptides related to the frog skin enzyme are present in several vertebrate species, including humans.
High faecal glucocorticoid levels predict mortality in ring-tailed lemurs (
Lemur catta
)
Authors: Ethan Pride R
Published: March 2005

Glucocorticoid levels are commonly used as measures of stress in wild animal populations, but their relevance to individual fitness in a wild population has not been demonstrated. In this study I followed 93 ring-tailed lemurs (
Lemur catta
) at Berenty Reserve in Madagascar, collecting 1089 faecal samples from individually recognized animals, and recording their survival over a 2 year period. I evaluated faecal glucocorticoid levels as predictors of individual survival to the end of the study. Animals with high glucocorticoid levels had a significantly higher mortality rate. This result suggests that glucocorticoid measures can be useful predictors of individual survival probabilities in wild populations. The ‘stress landscape’ indicated by glucocorticoid patterns may approximate the fitness landscape to which animals adapt.
Identification of the outer-membrane protein PagC required for the serum resistance phenotype in Salmonella enterica serovar Choleraesuis
Authors: Nishio Miki , Okada Nobuhiko , Miki Tsuyoshi , Haneda Takeshi , Danbara Hirofumi
Published: March 2005

Serum resistance is a crucial virulence factor for the development of systemic infections, including bacteraemia, by many pathogenic bacteria.Salmonella entericaserovar Choleraesuis is an important enteric pathogen that causes serious systemic infections in swine and humans. Here, it was found that, when introduced intoEscherichia coli, a recombinant plasmid carrying thepagCgene from a plasmid-based genomic library ofS. entericaserovar Choleraesuis conferred a high-level resistance to the bactericidal activity of pooled normal swine serum. The resistance was equal to the level conferred byrck, a gene encoding a 17 kDa outer-membrane protein which promotes the serum resistance phenotype inS. entericaserovar Typhimurium. Insertional mutagenesis of the clonedpagCgene generated a mutation that resulted in the loss of the serum resistance phenotype inE. coli. When this mutation was introduced into the chromosome ofS. entericaserovar Choleraesuis by homology recombination with the wild-type allele, the resulting strain could not produce PagC, and it showed a decreased level of resistance to complement-mediated killing. The mutation could be restored by introduction of the intactpagCgene on a plasmid, but not by introduction of the point-mutatedpagCgene. In addition, PagC was able to promote serum resistance in theS. entericaserovar Choleraesuis LPS mutant strain, which is highly sensitive to serum killing. Although PagC is not thought to confer serum resistance directly, these results strongly suggest that PagC is an important outer-membrane protein that plays an important role in the serum resistance ofS. entericaserovar Choleraesuis.
The validity of analyses testing the etiology of comorbidity between two disorders: a review of family studies
Authors: Rhee Soo Hyun , Hewitt John K. , Corley Robin P. , Stallings Michael C.
Published: March 2005

Background:  Knowledge regarding the causes of comorbidity between two disorders has a significant impact on research regarding the classification, treatment, and etiology of the disorders. Two main analytic methods have been used to test alternative explanations for the causes of comorbidity in family studies: biometric model fitting and family prevalence analyses. Unfortunately, the conclusions of family studies using these two methods have been conflicting. In the present study, we examined the validity of family prevalence analyses in testing alternative comorbidity models.

Method:  We reviewed 42 family studies that used family prevalence analyses to test three comorbidity models: the alternate forms model, the correlated liabilities model, or the three independent disorders model. We conducted the analyses used in these studies on datasets simulated under the assumptions of 13 alternative comorbidity models including the three models tested most often in the literature.

Results:  Results suggest that some analyses may be valid tests of the alternate forms model (i.e., two disorders are alternate manifestations of a single liability), but that none of the analyses are valid tests of the correlated liabilities model (i.e., a significant correlation between the risk factors for the two disorders) or the three independent disorders model (i.e., the comorbid disorder is a third, independent disorder).

Conclusion:  Family studies using family prevalence analyses may have made incorrect conclusions regarding the etiology of comorbidity between disorders.
The Roman Iron Age Tar Loaf From Albertsro, Sweden
Authors: Liselotte Bergström
Published: March 2005

This paper presents results of the analysis of a tar loaf from the Iron Age settlement of Albertsro, Södermanland, Sweden. The results are compared with the descriptions of previously found Scandinavian Bronze Age tar loaves (Harz Kuchen). The Albertsro loaf was analysed both chemically and morphologically, and was found to consist of birchbark tar together with pieces of birch-bark and animal fat, both probably added to give the loaf a more easily workable consistency. The loaf corresponds well in both appearance and content with other tar loaves a thousand years older. The place where it was found, in one of the roof postholes of a long house, and its date, in the Early Roman Iron Age, make this loaf a rather unusual artefact. It was probably deposited as a building sacrifice, perhaps as a good luck charm for the house and the area, and it may be an indication that some form of handicraft which involved the use of tar took place in the area. The paper concludes with a proposal that the Scandinavian tar loaves were produced as one stage in the processing of wood, leading to a material for the sealing, jointing and decoration of tools.
Classification of dyspepsia and response to treatment with proton‐pump inhibitors
Authors: Meineche‐Schmidt V.
Published: March 2005

Background : Lacking an objective ‘gold standard’ for diagnosing dyspepsia, several symptom‐based classifications have been suggested.

Aim : To assess if response to proton‐pump inhibitor treatment could provide useful information for current or future dyspepsia classification.

Methods : Post hoc analyses of 829 patients treated with omeprazole or placebo in a randomized‐controlled trial. The ‘true’ response to omeprazole (trial response minus placebo response) was assessed according to different classifications of dyspepsia and different symptoms.

Results : Symptoms described with the words ‘burning’ or ‘sour’ and patients with reflux‐like dyspepsia demonstrated high response to omeprazole treatment, whereas patients with abdominal pain or ulcer‐like dyspepsia responded unpredictably to omeprazole. The response to omeprazole in patients with epigastic pain was related to the pattern of other dyspeptic symptoms. Patients with heartburn or regurgitation overlapped extensively with patients with epigastric pain.

Conclusion : The study demonstrated significant problems in the current classification of dyspepsia: ‘the most bothersome symptom’ was not independently related to the omeprazole effect and, in patients with abdominal pain, the response to omeprazole was dependent on the presence or absence of other dyspeptic symptoms. The overlap of symptoms indicates that heartburn and regurgitation should be recognized as symptoms of dyspepsia in primary care.
Quantitative solid‐state 13C NMR spectroscopy of organic matter fractions in lowland rice soils
Authors: Smernik R. J. , Olk D. C. , Mahieu N.
Published: March 2005

Spin counting on solid‐state 13C cross‐polarization (CP) nuclear magnetic resonance (NMR) spectra of two humic fractions isolated from tropical lowland soils showed that only 32–81% of potential 13C NMR signal was detected. The observability of 13C NMR signal (Cobs) was higher in the mobile humic acid (MHA) than in the calcium humate (CaHA) fraction, and increased with increasing intensity of irrigated rice cropping. NMR observability appeared to be related to the nature of the organic carbon, with phenol‐ and methoxyl‐rich samples having the higher values of Cobs. The Bloch decay (BD) technique provided more quantitatively reliable 13C NMR spectra, as evidenced by values of Cobs in the range 91–100% for seven of the eight humic fractions studied. The BD spectra contained considerably more aryl and carbonyl signal, and less O–alkyl and alkyl signal, with the greatest differences between CP and BD spectra observed for the samples with low Cobs(CP). The causes of low CP observability were investigated using the spectral editing technique RESTORE ( REstoration of Spectra via TCH and T One Rho (T1ρH) Editing). Rapid T1ρH relaxation was found to be primarily responsible for the under‐representation of carbonyl carbon, whereas inefficient cross‐polarization was primarily responsible for the under‐representation of aryl carbon in CP spectra. Proton NMR relaxation rates T1H and T1ρH were found to correlate with other NMR properties and also with cropping management. Non‐uniform rates of T1H relaxation in two of the CaHA fractions enabled the generation of proton spin relaxation editing subspectra.
Down‐regulation of astroglial proteins in the rat cerebellum after portacaval anastomosis
Authors: Suárez I. , Bodega G. , Rubio M. , Fernández B.
Published: March 2005

The effect of short‐term portacaval anastomosis (PCA) on the expression of specific astroglial markers [glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS)] in the rat cerebellum was examined to determine the influences of PCA on astroglial cells. The results suggest that PCA directly interferes with astroglial cytoskeleton, as indicated by the irregular distribution and reduced expression of GFAP observed after 1 month. PCA also decreased GS immunoreactivity in the Bergmann glial processes of the molecular layer, as well as in astrocytes of the granule cell layer. It might also modulate glutamatergic nervous activity as GS expression was reduced in 1 month post‐PCA brains. Moreover, the GFAP and GS levels in PCA‐exposed rats were lower than in control rats. This might contribute to the appearance of encephalopathy by increasing extracellular glutamate and/or ammonia concentrations. These results show that short‐term PCA interferes with astroglial protein expression, with both GFAP and GS levels falling in astroglial cells.
Influence of porcine coat colour genotypes on haematological parameters, piglet birth weight and body weight gain until weaning
Authors: Fésüs L. , Zsolnai A. , Komlósi I.
Published: March 2005

Two F2 generations of an intercross between Hampshire boars and Hungarian Large White sows were produced to estimate the effects of the porcine KIT genotypes (II, Ii and ii) on quantitative and qualitative haematological indices, on piglet birth weight and growth performance until weaning. Piglets carrying the I allele had significantly fewer lymphocytes (p = 0.041) than the ii homozygotes, heterozygotes had measures between the two homozygotes. KIT genotypes did not influence white blood cells, red blood cells, haemoglobin and haematocrite. II genotype piglets were significantly lighter at birth than the ones carrying the recessive i allele, the effect of KIT genotypes on gain until weaning was not significant, but II piglets tended to gain less. The results of this study support the hypothesis of M. Johansson, H. Ellegren, L. Marklund, U. Gustavsson, E. Ringmar‐Cederberg, K. Andersson, I. Edfors‐Lilja and L. Andersson [(1992) Genomics, 14, 965] that the pleiotrophic effect of the porcine KIT mutations on haematopoietic cells must be mild.
Spatial and temporal population interactions between the parasitoids Cotesia flavipes and Tachinidae flies: considerations on the adverse effects of biological control practice
Authors: Rossi M. N. , Fowler H. G.
Published: March 2005

Biological control of Diatraea saccharalis is regarded as one of the best examples of successful classical biological control in Brazil. Since the introduction of the exotic parasitoid Cotesia flavipes, the decrease of D. saccharalis infestation in sugarcane fields has been attributed to the effectiveness of this agent. Recently, the native tachinid fly parasitoids (Lydella minense and Paratheresia claripalpis) have also been implicated in the success. Here, we investigated the spatial and temporal population interactions between C. flavipes and the tachinid flies, and provide a critical analysis of the biological control practice, focusing on the undesirable effects of introductions of exotic natural enemies. To investigate these questions, a large data set comprising information from two sugarcane mills located in the state of São Paulo, Brazil (Barra and São João Mills), was analysed. Analysis of the correlation between C. flavipes and tachinid fly population densities through time revealed that such populations were inversely correlated in the São João Mill and not correlated in the Barra Mill. Logistic regressions were computed to investigate the proportion of sites occupied by the parasitoid species at both mills as a function of time. An increasing trend in the proportion of sites occupied by C. flavipes was observed, with a concomitant decrease of the sites occupied by tachinid flies. This effect was more intense in the São João Mill. Thus, there is a convincing possibility that constant releases of C. flavipes decreased the tachinid fly populations, resulting in an undesirable effect of biological control practice.