bluuebunny/crossref_metadata_2025 huggingface dataset:
Genes encoding the α-carboxyltransferase subunit of acetyl-CoA carboxylase fromBrassica napusand parental species: cloning, expression patterns, and evolution
Authors: Li Zhi-Guo , Yin Wei-Bo , Guo Huan , Song Li-Ying , Chen Yu-Hong , Guan Rong-Zhan , Wang Jing-Qiao , Wang Richard R.-C. , Hu Zan-Min
Published: May 2010

Heteromeric acetyl coenzyme A carboxylase (ACCase), a rate-limiting enzyme in fatty acid biosynthesis in dicots, is a multi-enzyme complex consisting of biotin carboxylase, biotin carboxyl carrier protein, and carboxyltransferase (α-CT and β-CT). In the present study, four genes encoding α-CT were cloned from Brassica napus , and two were cloned from each of the two parental species, B. rapa and B. oleracea . Comparative and cluster analyses indicated that these genes were divided into two major groups. The major divergence between group-1 and group-2 occurred in the second intron. Group-2 α-CT genes represented the ancestral form in the genus Brassica. The divergence of group-1 and group-2 genes occurred in their common ancestor 12.96–17.78 million years ago (MYA), soon after the divergence of Arabidopsis thaliana and Brassica (15–20 MYA). This time of divergence is identical to that reported for the paralogous subgenomes of diploid Brassica species (13–17 MYA). Real-time reverse transcription PCR revealed that the expression patterns of the two groups of genes were similar in different organs, except in leaves. To better understand the regulation and evolution of α-CT genes, promoter regions from two sets of orthologous gene copies from B. napus, B. rapa, and B. oleracea were cloned and compared. The function of the promoter of gene Bnα-CT-1-1 in group-1 and gene Bnα-CT-2-1 in group-2 was examined by assaying β-glucuronidase activity in transgenic A. thaliana. Our results will be helpful in elucidating the evolution and regulation of ACCase in oilseed rape.
Impact of using updated seismic information on seismic hazard in western Canada
Authors: Goda K. , Hong H. P. , Atkinson G. M.
Published: May 2010

This study provides a preliminary assessment of the impact of new seismological information on the existing seismic hazard model, as implemented in the 2005 National building code of Canada (NBCC); this seismic hazard model was actually developed in the early 1990s, and thus there is significant new information available in the literature since then. A reassessment of seismic hazard is carried out by updating magnitude-recurrence relations based on the earthquake catalog up to the end of 2006, including conversion of all earthquake magnitudes to a homogenous moment magnitude scale. The recent ground-motion prediction equations, which update the knowledge base used in the 2005 NBCC, are also used. Focusing on Vancouver and Victoria, sensitivity analyses are carried out to investigate both individual and combined impacts of these updates on the uniform hazard spectra. The proposed model can be used as a guide to the direction in which future seismic hazard models for western Canada may move.
Enrichment and characterization of MTBE-degrading cultures under iron and sulfate reducing conditions
Authors: Raynal M. , Crimi B. , Pruden A.
Published: May 2010

The aim of this study was to enrich cultures capable of anaerobic methyl tert-butyl ether (MTBE) biodegradation and to determine their compositions using biomolecular tools. MTBE biodegradation as the sole carbon source was observed under Fe(III) and SO42–reducing conditions and with both electron acceptors present together. The estimated MTBE biodegradation rates ranged from 3.80 to 9.20 mg·L–1·d–1when Fe(III) was the sole electron acceptor, from 1.46 to 1.70 mg·L–1·d–1when Fe(III) and SO42–were present together, and from 1.13 to 1.71 mg·L–1·d–1when SO42–was the sole electron acceptor. Five to eight members were identified in the three consortia, and their characteristics were congruent with the electron acceptor conditions. A clone 99% similar to a recently described MTBE degrader, Ochrobactrum cytisi, was detected in both cultures containing Fe(III). Other 16S rRNA gene sequences detected were highly similar at the species or genus level to additional known MTBE degraders, including Pseudomonas spp. (cometabolic), Sphinogomonas, Achromobacter, and Rhodococcus. Results suggest that the buildup of intermediates and (or) the presence of sulfides had an inhibitory effect on biodegradation. Anaerobic MTBE biodegradation remains poorly understood, and degrading strains still have not been identified to date. This work represents the first detailed 16S rRNA gene profiling of highly enriched iron- and sulfate-reducing MTBE-degrading consortia. These results may provide useful biomarkers to support current efforts for confirming anaerobic MTBE biodegradation in the field.
Long-term thermal two- and three-dimensional analysis of roller compacted concrete dams supported by monitoring verification
Authors: Kuzmanovic Vladan , Savic Ljubodrag , Stefanakos John
Published: May 2010

This paper presents two-dimensional (2D) and three-dimensional (3D) numerical models for unsteady phased thermal analysis of RCC dams. The time evolution of a thermal field has been modeled using the actual dam shape, RCC technology and the adequate description of material properties. Model calibration and verification has been done based on the field investigations of the Platanovryssi dam, the highest RCC dam in Europe. The results of a long-term thermal analysis, with actual initial and boundary conditions, have shown a good agreement with the observed temperatures. The influence of relevant parameters on the thermal field of RCC dams has been analyzed. It is concluded that the 2D model is appropriate for the thermal phased analysis, and that the boundary conditions and the mixture properties are the most influential on the RCC dam thermal behavior.
Effect of co-contaminants on the dechlorination of polychlorinated biphenylsPaper submitted to the Journal of Environmental Engineering and Science.
Authors: Kone Macoura , Chang Yanjun , Achari Gopal , Langford Cooper H.
Published: May 2010

A promising photolysis based technology to dechlorinate polychlorinated biphenyls (PCBs), extracted from soils, in alkaline isopropanol (IPA) as reaction medium has been proposed. To be marketable the impact of co-contaminants extracted along with the PCBs, on the photodechlorination process needs investigation. In this paper the effectiveness of the photodeclorination process on PCBs extracted from samples of a representative soil containing co-contaminants is reported. The photodechlorination of PCBs extracted from weathered soils showed promising results of more than 76% dechlorination within the first hour of UV irradiation. Nearly complete dechlorination (96%) was achieved after 2 h of UV irradiation. To provide quantitative controlled appraisal of the effect of co-contaminants and explanation of the effects, dechlorination of neat Aroclor 1254 in the presence of the common co-contaminant, transformer oil, was evaluated. Further, the effect of transformer oil on some of the individual PCB congeners in the Aroclor mixture was also studied. The difference in the maximum percentage dechlorination of PCBs with and without transformer oil is 15%.
Residue patterning in helix interiorsThis paper is one of a selection of papers published in this special issue entitled “Canadian Society of Biochemistry, Molecular & Cellular Biology 52nd Annual Meeting — Protein Folding: Principles and Diseases” and has undergone the Journal's usual peer review process.
Authors: Wathen Brent , Jia Zongchao
Published: May 2010

The α-helix remains a focus of research because of its importance to protein folding and structure. Nevertheless, despite numerous empirical, computational, and theoretical studies, the fundamental structural properties governing their formation and stability are still unclear. We have examined the statistical occurrence of polar and apolar residue patterning in helical interiors in a large, non-redundant dataset, and compared these patterns with those found in other structural environments. While the familiar amphipathic distributions for both polar and apolar residues are evident, our analysis also finds significant differences between these distributions. Non-amphipathic signals can also be discerned within both distributions. Most interestingly, among various positional patterning, an analysis of immediate (i,i + 1) helical neighbours found: (i) clear neighbouring preferences, with high (low) occurrences of hydrophobics (hydrophilics) next to Gly, Pro, and short polar residues; (ii) high negative (positive) correlation between residue helical propensities and the degree of neighbouring hydrophobicity (hydrophilicity); and (iii) a preferred ordering among neighbours, implying an inherent helix directionality. Because (i,i + 1) helical pairs have limited side chain – side chain interactions, thermodynamic considerations cannot readily explain these observations, nor can evolutionary pressures that enhance tertiary interactions via amphipathicity, as this particular spacing does not segregate residues onto either the same or opposing helical faces. We suggest that the mechanism of helix formation may be partly responsible for these observations. In particular, the high negative correlation between residue helical propensities and neighbouring hydrophobicity suggests that hydrophobicity may play a more important role in helix formation than currently recognized.
Structural disorder and dynamics of elastinThis paper is one of a selection of papers published in this special issue entitled “Canadian Society of Biochemistry, Molecular & Cellular Biology 52nd Annual Meeting — Protein Folding: Principles and Diseases” and has undergone the Journal's usual peer review process.
Authors: Muiznieks Lisa D. , Weiss Anthony S. , Keeley Fred W.
Published: May 2010

Elastin is a self-assembling, extracellular-matrix protein that is the major provider of tissue elasticity. Here we review structural studies of elastin from over four decades, and draw together evidence for solution flexibility and conformational disorder that is inherent in all levels of structural organization. The characterization of disorder is consistent with an entropy-driven mechanism of elastic recoil. We conclude that conformational disorder is a constitutive feature of elastin structure and function.
Apolipoprotein B100 biogenesis: a complex array of intracellular mechanisms regulating folding, stability, and lipoprotein assemblyThis paper is one of a selection of papers published in this special issue entitled “Canadian Society of Biochemistry, Molecular & Cellular Biology 52nd Annual Meeting — Protein Folding: Principles and Diseases” and has undergone the Journal's usual peer review process.
Authors: Rutledge Angela C. , Su Qiaozhu , Adeli Khosrow
Published: May 2010

Apolipoprotein B100 (apoB) is a large amphipathic lipid-binding protein that is synthesized by hepatocytes and used to assemble and stabilize very low density lipoproteins (VLDL). It may have been derived through evolution from other lipid-associating proteins such as microsomal triglyceride transfer protein or vitellogenin. The correct folding of apoB requires assistance from chaperone proteins in co-translational lipidation, disulfide bond formation, and glycosylation. Any impairment in these processes results in co-translational targeting of the misfolded apoB molecule for proteasomal degradation. In fact, most of the regulation of apoB production is mediated by intracellular degradation. ApoB that misfolds post-translationally, perhaps as a result of oxidative stress, may be eliminated through autophagy. This review focuses on the proposed pentapartite domain structure of apoB, the role that each domain plays in the binding of lipid species and regulation of apoB synthesis, and the process of VLDL assembly. The factors involved in the recognition, ubiquitination, and proteasomal delivery of defective apoB molecules are also discussed.
Nanopore analysis of the interaction of metal ions with prion proteins and peptidesThis paper is one of a selection of papers published in this special issue entitled “Canadian Society of Biochemistry, Molecular & Cellular Biology 52nd Annual Meeting — Protein Folding: Principles and Diseases” and has undergone the Journal's usual peer review process.
Authors: Stefureac Radu I. , Madampage Claudia Avis , Andrievskaia Olga , Lee Jeremy S.
Published: May 2010

Nanopore analysis can be used to study conformational changes in individual peptide or protein molecules. Under an applied voltage there is a change in the event parameters of blockade current or time when a molecule bumps into or translocates through the pore. If a molecule undergoes a conformational change upon binding a ligand or metal ion the event parameters will be altered. The objective of this research was to demonstrate that the conformation of the prion protein (PrP) and prion peptides can be modulated by binding divalent metal ions. Peptides from the octarepeat region (Octa2, (PHGGGWGQ)2 and Octa 4, (PHGGGWGQ)4), residues 106–126 (PrP106–126), and the full-length Bovine recombinant prion (BrecPrP) were studied with an α-hemolysin pore. Octa2 readily translocated the pore but significant bumping events occurred on addition of Cu(II) and to a lesser extent Zn(II), demonstrating that complex formation was occurring with concomitant conformational changes. The binding of Cu(II) to Octa4 was more pronounced and at high concentrations only a small proportion of the complex could translocate. Addition of Zn(II) also caused significant changes to the event parameters but Mg(II) and Mn(II) were inert. Addition of Cu(II) to PrP106–126 caused the formation of a very tight complex, which could not translocate the pore. Small changes were observed with Zn(II), but not with Mg(II) or Mn(II). Analysis of BrecPrP showed that about 37% were translocation events, but on addition of Cu(II) or Zn(II) these disappeared and only bumping events were recorded. Suprisingly, addition of Mn(II) caused an increase in translocation events to about 64%. Thus, conformational changes to prions upon binding metal ions are readily observed by nanopore analysis.
Bacterial–protozoal interactions in a microbial community of rumen ciliateEntodinium caudatumculture under mercury stress
Authors: Kišidayová S. , Houserová P. , Váradyová Z. , Mihaliková K. , Pristaš P. , Javorský P.
Published: May 2010

We examined the role of rumen ciliates, using Entodinium caudatum as a model organism, in the detoxification of soluble mercury(II) in vitro under conditions with enhanced or reduced diversity of a co-culture bacterial population as well as the effects of long-term mercury(II) stress on in vitro fermentation parameters and major mercury detoxification products. The E. caudatum growth depended on the capability of the co-culture bacterial population to develop resistance to mercury(II) chloride and on culture conditions. The production of fermentation gas was reduced (P < 0.01) in contrast to methane production. Proportions of volatile fatty acids were affected; however, the total concentration of volatile fatty acids was not influenced. No organic mercury species were detected after long-term application (>1 month) of mercury(II) chloride. The major mercury species was inorganic mercury(II) with substantial accumulation in the bacterial fraction (70%) and less in black sediment (21%) and ciliate fraction (9%) at the 25 µmol/L mercury(II) dose. The data indicate that free-living bacteria protect the ciliate cells by transforming mercury(II) into its insoluble forms.
Changes in the structure and diversity of bacterial communities during the process of adaptation to organic wastewater
Authors: Li Junmin , Jin Zexin , Yu Binbin
Published: May 2010

To explore changes in the structure and diversity of activated sludge-derived microbial communities during adaptation to gradual increases in the concentration of wastewater, RAPD–PCR and the combination of PCR amplification of 16S rRNA genes with denaturing gradient gel electrophoresis (DGGE) analysis were used. In bacterial communities exposed to 0%, 5%, 10%, 20%, or 40% wastewater, there were 27, 25, 18, 17 and 16 bands, respectively, based on DGGE data, while there were 69, 83, 97, 86, and 88 bands, respectively, based on RAPD data. The community similarity index among bacterial communities during the process of adaptation to different concentrations of wastewater was different based on DGGE and RAPD data. Based on DGGE and RAPD profiles, the Shannon–Weiner and Simpson’s diversity indices decreased sharply upon exposure to 10% wastewater, indicating that 10% wastewater might be a critical point at which the growth of bacteria could be significantly inhibited and the genotypic diversity could change. This indicated that changes in structure and diversity might have an inhibitory effect on the toxicity of organic matter and that selection and adaptation could play important roles in the changes.
Production and properties of α-amylase fromBacillussp. BKL20
Authors: Kubrak Olha I. , Storey Janet M. , Storey Kenneth B. , Lushchak Volodymyr I.
Published: May 2010

As a result of screening Bacillus sp. strains isolated from different natural substrates, strain BKL20 was identified as a producer of a thermostable alkaline α-amylase. Maximum production of this α-amylase was achieved by optimizing culture conditions. Production of α-amylase seemed to be independent of the presence of starch in the culture medium and was stimulated by the presence of peptone (0.3%, m/v) and yeast extract (0.2%, m/v). The enzyme was thermostable and retained amylolytic activity after 30 min of incubation at 60 and 70 °C. High activity was maintained over a broad pH range, from 6.0 to 11.0, and the enzyme remained active after alkaline incubation for 24 h. Bacillus sp. BKL20 α-amylase was not stimulated by Ca2+or other bivalent metal cations and was not inhibited by EGTA or EDTA at 1–10 mmol/L, suggesting that this α-amylase is a Ca2+-independent enzyme. It also showed good resistance to both oxidizing (H2O2) and denaturating (urea) agents.
Detection of natural barriers to movement of lake sturgeon (Acipenser fulvescens) within the Namakan River, Ontario
Authors: Welsh A. B. , McLeod D. T.
Published: May 2010

Many populations of lake sturgeon ( Acipenser fulvescens Rafinesque, 1817) are below historic population sizes, and migration barriers have likely contributed to some of these population declines. Dams and natural barriers can potentially isolate populations along a single river and can have a strong effect on the ability of lake sturgeon to move upstream. Along the Namakan River in Ontario, Canada, a series of natural rapids could impede movement of lake sturgeon and fragment the sturgeon into several small populations. Movement patterns of lake sturgeon were assessed using genetics and acoustic telemetry. Samples were collected from five locations along the river, each one separated by a rapid or falls, and were analyzed at 12 microsatellite loci. No significant genetic differences were observed between the five segments, indicating that the groups of lake sturgeon are not isolated. There were no significant differences in genetic diversity between the five segments. Therefore, migration is likely occurring both upstream and downstream. The acoustic telemetry study also confirmed bidirectional movement of adult fish. The natural rapids and falls along the Namakan River do not appear to be a significant barrier to movement of lake sturgeon, and the lake sturgeon within this river represent a single population.
Sensory complement model helps to predict diel alarm response patterns in juvenile Atlantic salmon (Salmo salar) under natural conditions
Authors: Leduc Antoine O.H.C. , Kim Jae-Woo , Macnaughton Camille J. , Brown Grant E.
Published: May 2010

Fish rely on both chemical and visual cues to evaluate predation risk. Decisions with respect to activity partitioning in time (i.e., night vs. day) rely on accurate assessment of predation risk relative to energy intake; predation risk is generally thought to be lower at night at the expense of feeding opportunities. At night, the sensory complement model predicts greater reliance on chemical perception of risk. Under this condition, a lower ability to use vision should result in a more conservative response to chemical cues than during the day. We tested this hypothesis under natural conditions by comparing the alarm response of young-of-the-year Atlantic salmon ( Salmo salar L., 1758) under summer day and night conditions in salmon nursery streams. We found that salmon responded to the alarm cues to a significantly greater extent at night. This suggests that the sensory complement model may be correct and that nocturnal perception of risk may be generally higher than previously believed for juvenile salmon in the wild. In the absence of a more precise indicator of risk (e.g., vision), a greater reliance on chemosensory risk assessment at night may cause fish to shift to more risk-adverse behaviour.
Roads, logging, and the large-mammal community of an eastern Canadian boreal forest
Authors: Bowman Jeff , Ray Justina C. , Magoun Audrey J. , Johnson Devin S. , Dawson F. Neil
Published: May 2010

We evaluated hypotheses concerning the distributions of large mammals in a 60 000 km2study area that encompassed the contact zone between Ontario’s roadless north and the postlogging southern landscape. We estimated occurrence probability in 575 sample units for woodland caribou ( Rangifer tarandus caribou (Gmelin, 1788)), wolverine ( Gulo gulo (L., 1758)), gray wolf ( Canis lupus L., 1758), moose ( Alces alces (L., 1758)), and white-tailed deer ( Odocoileus virginianus (Zimmerman, 1780)). We used ordinations and spatial regressions to assess the contributions of parameters to species occurrence. Roads and cutovers were most abundant in the south, leading to an increased prevalence of deciduous forest. Mature coniferous forest, however, occurred most commonly in the north. Occurrence probabilities for moose and deer were greatest in the south, in close association with deciduous trees. Wolf occurrence was also greatest in the south, positively related to both deciduous forest and road density. Caribou occurrence, however, was positively related to mature coniferous forest and negatively related to both wolf occurrence and roads. Wolverine occurrence was negatively related to deciduous forest. Our surveys demonstrated distinct mammal communities in the northern and southern halves of our study area, a separation that appeared to be mediated by deciduous forest and roads.
Behavior and survival of white-tailed deer neonates in two suburban forest preserves
Authors: Piccolo B. P. , Van Deelen T. R. , Hollis-Etter K. , Etter D. R. , Warner R. E. , Anchor C.
Published: May 2010

Neonatal survival influences growth of unhunted populations of suburban white-tailed deer ( Odocoileus virginianus (Zimmerman, 1780)). Understanding the interaction of habitat and survival may inform conservation efforts and studies of life history of cervids at high density. We chose two forest preserves representative of forests in suburban Chicago. We radio-marked 56 neonates (1999–2001) to investigate mortality and habitat use. Through 1 July, 21 of 29 (72%) neonates and 6 of 22 (27%) died mostly because of predation by coyotes ( Canis latrans Say, 1823). Akaike’s information criterion suggested that optimal mark–recapture models of survival contained covariates reflecting differences by preserve and timing chosen to coincide with behavioral change from hiding to accompanying the doe. Survival was lower during early parturition (0.26–0.78) relative to the latter part (0.90–0.96). Early fawns (hiders) at one site had lower survival (0.26–0.29) than fawns at the other (0.78). Lower survival associated with larger home ranges, greater movement, and reduced understory cover, suggesting that hiding cover may mediate fawn survival in the presence of predators. Our study demonstrates spatial heterogeneity in population biology of suburban deer and suggests that site-specific differences may influence neonate survival in the face of coyote predation.
TWO-WAY QUANTUM-BIT-STRING COMMITMENT
Authors: LI CHUAN-MING , HWANG TZONELIH
Published: May 2010

Due to the high cost of the qubit generating device (QGD) (the single photon source), QGD may not be available at the same time in both communicating parties (Alice and Bob) who have to execute the quantum bit string commitment (QBSC) protocol for some application environments. All the existing QBSC protocols allow one-way commitment i.e., only the party (Bob) who possesses the QGD is allowed to commit a bit string to Alice who does not have the QGD, but not the other way around. However, what happens if Alice, who does not have the QGD, is required to commit a bit string to Bob? The current QBSC protocols fail to provide a solution in this case. Therefore, the purpose of this paper is to allow Alice, who is not equipped with the QGD, to commit a bit string to Bob who has the QGD. With our proposed protocol, together with previously proposed QBSC protocols, Alice and Bob can perform two-way commitment, even though Bob is the only party who is equipped with the QGD.
SYNTHESIS OF AN IONIC LIQUID-BASED MAGNETORHEOLOGICAL FLUID DISPERSINGFe84Nb3V4B9NANOCRYSTALLINE POWDERS
Authors: CAO LINGFEI , PARK HYUNSEO , DODBIBA GJERGJ , FUJITA TOYOHISA
Published: May 2010

A new magnetorheological (MR) fluid was synthesized by dispersing Fe84Nb3V4B9nanocrystalline powders in a nonvolatile ionic liquid (N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate), which is stable from 282K to 573K. The structure, morphology, and magnetization of Fe84Nb3V4B9nanocrystalline powders prepared by mechanical alloying were analyzed by using an X-ray diffractometer (XRD), a vibrating sample magnetometer (VSM), and a scanning electron microscopy (SEM), respectively. The magnetic clusters of the synthesized MR fluid were observed by using a digital microscope, and its MR properties were measured by using a cone-plate type viscometer. The experimental results showed that Fe84Nb3V4B9nanocrystalline powders with an average grain size of 10–20 nm can be prepared by mechanical alloying. The MR fluid is magnetic-field-responsive, behaves like non-Newtonian fluids, and its magnetorheological properties are influenced by the applied magnetic flux density and the width of magnetic clusters.
DYNAMIC INSTABILITY OF COMPOSITE AND SANDWICH LAMINATES WITH INTERFACIAL SLIPS
Authors: CHAKRABARTI ANUPAM , SHEIKH ABDUL HAMID
Published: May 2010

The dynamic instability of composite and sandwich laminates with interfacial slips is studied in this paper. An efficient finite element model recently developed by the authors is used for the purpose. The plate model is based on a refined higher-order shear deformation theory, where the transverse shear stresses are continuous at the layer interfaces with stress free conditions at plate top and bottom. A linear spring-layer model is used to model the interfacial slips by introducing in-plane displacement jump at the interfaces. Some interesting new results are presented in this paper, which are useful to understanding of the behavior of laminated composite materials.
FIRE RESPONSES AND RESISTANCE OF CONCRETE-FILLED STEEL TUBULAR FRAME STRUCTURES
Authors: YU MIN , ZHA XIAOXIONG , YE JIANQIAO , Li YI
Published: May 2010

This paper presents the results of dynamic responses and fire resistance of concrete-filled steel tubular (CFST) frame structures in fire conditions by using the nonlinear finite element method. Both strength and stability criteria are considered in the collapse analysis. The frame structures are constructed with circular CFST columns and steel beams of I-sections. In order to validate the finite element solutions, the numerical results are compared with those from a fire resistance test on CFST columns. The finite element model is then adopted to simulate the behavior of frame structures in fire. The structural responses of the frames, including the critical temperature and fire-resisting limit time, are obtained for the ISO-834 standard fire. Parametric studies are carried out to show their influence on the load capacity of the frame structures in fire. Suggestions and recommendations are presented for possible adoption in future construction and design of similar structures.
ACOUSTIC WAVE IN PIEZOELECTRIC COUPLED PLATES WITH OPEN CIRCUIT
Authors: WANG Q. , WU N. , QUEK S. T.
Published: May 2010

An accurate modeling of the piezoelectric effect of coupled structures is essential to application of piezoelectric materials as sensors and actuators in engineering structures, such as Micro-Electro-Mechanical Systems and Interdigital Transducer for health monitoring of structures. This paper presents a simulation for the shear horizontal wave propagation in an infinite metal plate surface bonded by a piezoelectric layer with open electrical circuit, with focus on the dispersion characteristics of a metal core bonded by a layer of piezoelectric material to be used in health monitoring of structures. The dispersive characteristics and mode shapes of the deflection, electric potential, and electric displacement of the piezoelectric layer are theoretically derived. The results from numerical simulations show that the phase velocity of the piezoelectric coupled plate approaches the bulk-shear wave velocity of the substrate at high wavenumbers. The mode shapes of electric potential and deflection of the piezoelectric layer with steel substrates change from a shape with few zero nodes to one with more zero nodes at higher wavenumbers and with thicker piezoelectric layer. For the coupled plate with gold substrates at higher wavenumbers, the electric potential is found to jump from null at the interface of the piezoelectric layer and the substrate to a constant at the surface of the piezoelectric layer along the thickness direction. These findings are useful to the design of sensors using the piezoelectric coupled structures.
THE IMPACT OF ORGANISATIONAL CONTEXT AND COMPETENCES ON INNOVATION AMBIDEXTERITY
Authors: BRION SÉBASTIEN , MOTHE CAROLINE , SABATIER MARÉVA
Published: May 2010

Research into organisation theory contains abundant evidence of the positive effects of ambidexterity on a firm's performance, and of the influence of organisational context on ambidexterity. The present research tests whether organisational context affects innovation ambidexterity. Our results, based on a dataset of 108 large innovative firms, show that firms combining exploration innovation and exploitation innovation should adopt long-term practices that favour risk-taking and creativity, and thereby build an organisational context suited to innovation ambidexterity. Competences were found to have a strong moderating effect. These results have important managerial and theoretical implications. In the case of innovation, firms that simultaneously pursue exploitation and exploration activities should carefully consider how they combine competences and organisational context.
DEVELOPING A PROCESS INNOVATION WORK PROCESS: THE LKAB EXPERIENCE
Authors: LAGER THOMAS , HALLBERG DAN , ERIKSSON PIERRE
Published: May 2010

It goes without saying that most companies today need a product innovation work process. The importance of process innovation in many sectors of the process industries should, however, make the development of a process innovation work process a growing concern in many process-based companies. This case study describes the development of such a work process at LKAB, a producer of high-quality iron ore pellets mainly for the European steel industry. Starting with a previously published conceptual model of the work process from a research project in other process industries, the development work is initially introduced in detail. The complete work process is then presented together with a cross-functional process map, checklists and a supplementary process description. The development of the work processes was a combination of a recording of LKAB's best practices coupled with the use of externally published research results and information on work process development. Finally, experience from the development and organisational implementation is discussed. It is the opinion of the project group that if properly applied, this work process will give structure, methodological guidance and efficiency in process innovation. But reaping those rewards will require persistence and discipline at all levels of the company. The purpose of this article is to provide theoretical insight and practical guidance on how to develop an innovation work process in the process industries, specifically, a process innovation work process. The successful development of this work process was considered of such importance to LKAB technology and business development that it resulted in an overall top management initiative to develop and improve all company innovation work processes, with a view to improving innovation output, project management efficiency and organisational learning.
Chronic alcohol consumption and intestinal thiamin absorption: effects on physiological and molecular parameters of the uptake process
Authors: Subramanya Sandeep B. , Subramanian Veedamali S. , Said Hamid M.
Published: May 2010

Thiamin is essential for normal cellular functions, and its deficiency leads to a variety of clinical abnormalities. Humans and other mammals obtain the vitamin via intestinal absorption. The intestine is exposed to two sources of thiamin, a dietary and a bacterial (i.e., normal microflora of the large intestine) source. Chronic alcohol consumption is associated with thiamin deficiency, which is caused (in part) by inhibition in intestinal thiamin absorption. However, little is known about the physiological and molecular aspects of the intestinal thiamin uptake process that are affected by chronic alcohol use. To address these issues, we used rats fed an alcohol-liquid diet and human intestinal epithelial HuTu-80 cells chronically exposed to ethanol as model systems. The results showed that chronic alcohol feeding to rats led to a significant inhibition in carrier-mediated thiamin transport across both the jejunal brush-border membrane and basolateral membrane domains. This was associated with a significant reduction in level of expression of thiamin transporter-1 (THTR-1), but not THTR-2, at the protein and mRNA levels. Level of expression of the heterogenous nuclear RNA of THTR-1 in the intestine of alcohol-fed rats was also decreased compared with their pair-fed controls. Chronic alcohol feeding also caused a significant inhibition in carrier-mediated thiamin uptake in rat colon. Studies with HuTu-80 cells chronically exposed to ethanol also showed a significant inhibition in carrier-mediated thiamin uptake. This inhibition was associated with a reduction in level of expression of human THTR-1 and THTR-2 at the protein, mRNA, and transcriptional (promoter activity) levels. These studies demonstrate that chronic alcohol feeding inhibits intestinal thiamin absorption via inhibition of the individual membrane transport event across the polarized absorptive epithelial cells. Furthermore, the inhibition is, at least in part, mediated via transcriptional mechanism(s).
Sex differences in mechanisms of cardiac excitation-contraction coupling in rat ventricular myocytes
Authors: Farrell Spring R. , Ross Jenna L. , Howlett Susan E.
Published: May 2010

Components of excitation-contraction (E-C) coupling were compared in ventricular myocytes isolated from 3-mo-old male and female rats. Ca2+ concentrations (fura-2) and cell shortening (edge detector) were measured simultaneously (37°C). Membrane potential and ionic currents were measured with microelectrodes. Action potentials were similar in male and female myocytes, but contractions were smaller and slower in females. In voltage-clamped cells, peak contractions were smaller in females than in males (5.1 ± 0.7% vs. 7.7 ± 0.8% diastolic length, P < 0.05). Similarly, Ca2+ transients were smaller in females than in males and the rate of rise of the Ca2+ transient was slower in females. Despite smaller contractions and Ca2+ transients in females, Ca2+ current density was similar in both groups. Sarcoplasmic reticulum Ca2+ content, assessed with caffeine, did not differ between the sexes. However, E-C coupling gain (rate of Ca2+ release/Ca2+ current) was smaller in females than in males (157.0 ± 15.6 vs. 338.4 ± 54.3 (nM/s)/(pA/pF), P < 0.05). To determine whether the reduced gain in female cells was due to changes in unitary Ca2+ release, spontaneous Ca2+ sparks were evaluated (fluo-4, 37°C). Spark frequencies and widths were similar in both groups, but spark amplitudes were smaller in females than in males (0.56 ± 0.01 vs. 0.64 ± 0.01 ΔF/F0, P < 0.05). Spark durations also were shorter in females than in males (full duration at half-maximum = 14.86 ± 0.17 vs. 16.25 ± 0.27 ms, P < 0.05). These observations suggest that decreases in the size and duration of Ca2+ sparks contributes to the decrease in E-C coupling gain in female myocytes. Thus, differences in cardiac contractile function arise, in part, from differences in unitary Ca2+ release between the sexes.
Apparent PKA activity responds to intermittent hypoxia in bone cells: a redox pathway?
Authors: Zhang Yan-Liang , Tavakoli Hesam , Chachisvilis Mirianas
Published: May 2010

We studied hypoxia-induced dynamic changes in the balance between PKA and PKA-counteracting phosphatases in the microfluidic environment in single cells using picosecond fluorescence spectroscopy and intramolecular fluorescence resonance energy transfer (FRET)-based sensors of PKA activity. First, we found that the apparent PKA activity in bone cells (MC3T3-E1 cells) and endothelial cells (bovine aortic endothelial cells) is rapidly and sensitively modulated by the level of O2 in the media. When the O2 concentration in the glucose-containing media was lowered due to O2 consumption by the cells in the microfluidic chamber, the apparent PKA activity increases; the reoxygenation of cells under hypoxia leads to a rapid (∼2 min) decrease of the apparent PKA activity. Second, lack of glucose in the media led to a lower apparent PKA activity and to a reversal of the response of the apparent PKA activity to hypoxia and reoxygenation. Third, the apparent PKA activity in cells under hypoxia was predominantly regulated via a cAMP-independent pathway since 1) changes in the cAMP level in the cells were not detected using a cAMP FRET sensor, 2) the decay of cAMP levels was too slow to account for the fast decrease in PKA activity levels in response to reoxygenation, and 3) the response of the apparent PKA activity due to hypoxia/reoxygenation was not affected by an adenylate cyclase inhibitior (MDL-12,330A) at 1 mM concentration. Fourth, the immediate onset of ROS accumulation in MC3T3-E1 cells subjected to hypoxia and the sensitivity of the apparent PKA acitivity to redox levels suggest that the apparent PKA activity change during hypoxia and reoxygenation in this study can be linked to a redox potential change in response to intermittent hypoxia through the regulation of activities of PKA-counteracting phosphatases such as protein phosphatase 1. Finally, our results suggest that the detection of PKA activity could be used to monitor responses of cells to hypoxia in real time.
cGMP increases antioxidant function and attenuates oxidant cell death in mouse lung microvascular endothelial cells by a protein kinase G-dependent mechanism
Authors: Stephens R. Scott , Rentsendorj Otgonchimeg , Servinsky Laura E. , Moldobaeva Aigul , Damico Rachel , Pearse David B.
Published: May 2010

Increasing evidence suggests that endothelial cytotoxicity from reactive oxygen species (ROS) contributes to the pathogenesis of acute lung injury. Treatments designed to increase intracellular cGMP attenuate ROS-mediated apoptosis and necrosis in several cell types, but the mechanisms are not understood, and the effect of cGMP on pulmonary endothelial cell death remains controversial. In the current study, increasing intracellular cGMP by either 8pCPT-cGMP (50 μM) or atrial natriuretic peptide (10 nM) significantly attenuated cell death in H2O2-challenged mouse lung microvascular (MLMVEC) monolayers. 8pCPT-cGMP also decreased perfusate LDH release in isolated mouse lungs exposed to H2O2or ischemia-reperfusion. The protective effect of increasing cGMP in MLMVECs was accompanied by enhanced endothelial H2O2scavenging (measured by H2O2electrode) and decreased intracellular ROS concentration (measured by 2′,7′-dichlorofluorescin fluorescence) as well as decreased phosphorylation of p38 MAPK and Akt. The cGMP-mediated cytoprotection and increased H2O2scavenging required >2 h of 8pCPT-cGMP incubation in wild-type MLMVEC and were absent in MLMVEC from protein kinase G (PKGI)−/− mice suggesting a PKGI-mediated effect on gene regulation. Catalase and glutathione peroxidase 1 (Gpx-1) protein were increased by cGMP in wild-type but not PKGI−/− MLMVEC monolayers. Both the cGMP-mediated increases in antioxidant proteins and H2O2scavenging were prevented by inhibition of translation with cycloheximide. 8pCPT-cGMP had minimal effects on catalase and Gpx-1 mRNA. We conclude that cGMP, through PKGI, attenuated H2O2-induced cytotoxicity in MLMVEC by increasing catalase and Gpx-1 expression through an unknown posttranscriptional effect.
Predictive Biomarkers of Sensitivity to the Phosphatidylinositol 3′ Kinase Inhibitor GDC-0941 in Breast Cancer Preclinical Models
Authors: O'Brien Carol , Wallin Jeffrey J. , Sampath Deepak , GuhaThakurta Debraj , Savage Heidi , Punnoose Elizabeth A. , Guan Jane , Berry Leanne , Prior Wei Wei , Amler Lukas C. , Belvin Marcia , Friedman Lori S. , Lackner Mark R.
Published: May 2010

Purpose: The class I phosphatidylinositol 3′ kinase (PI3K) plays a major role in proliferation and survival in a wide variety of human cancers. A key factor in successful development of drugs targeting this pathway is likely to be the identification of responsive patient populations with predictive diagnostic biomarkers. This study sought to identify candidate biomarkers of response to the selective PI3K inhibitor GDC-0941.

Experimental Design: We used a large panel of breast cancer cell lines and in vivo xenograft models to identify candidate predictive biomarkers for a selective inhibitor of class I PI3K that is currently in clinical development. The approach involved pharmacogenomic profiling as well as analysis of gene expression data sets from cells profiled at baseline or after GDC-0941 treatment.

Results: We found that models harboring mutations in PIK3CA, amplification of human epidermal growth factor receptor 2, or dual alterations in two pathway components were exquisitely sensitive to the antitumor effects of GDC-0941. We found that several models that do not harbor these alterations also showed sensitivity, suggesting a need for additional diagnostic markers. Gene expression studies identified a collection of genes whose expression was associated with in vitro sensitivity to GDC-0941, and expression of a subset of these genes was found to be intimately linked to signaling through the pathway.

Conclusion: Pathway focused biomarkers and the gene expression signature described in this study may have utility in the identification of patients likely to benefit from therapy with a selective PI3K inhibitor. Clin Cancer Res; 16(14); 3670–83. ©2010 AACR.
Negative Correlation between Neuropeptide Y Profile in the Cerebrospinal Fluid and Growth Hormone Pulses in the Peripheral Circulation in Goats
Authors: Yonezawa Tomohiro , Mogi Kazutaka , Li Jun You , Sako Ryuji , Manabe Noboru , Yamanouchi Keitaro , Nishihara Masugi
Published: May 2010

Background/Aims: Growth hormone (GH) is secreted in pulsatile fashion, but the involvement of neuropeptides in the generation of GH pulses is not fully understood. The present study was conducted to elucidate the relationship between GH pulses and neuropeptide levels in the cerebrospinal fluid (CSF) of the third ventricle in ovariectomized goats. Methods: CSF and plasma samples were collected every 15 min. Levels of plasma GH and profiles of GH-releasing hormone (GHRH), somatostatin (SRIH) and neuropeptide Y (NPY) in the CSF were measured by radioimmunoassay. Pulse/trough characteristics and correlations were assessed by the ULTRA algorithm, cross-correlation analysis and approximate entropy test. Results: The periodicity of GH pulses was 2.20 h. Although most GH pulses were associated with GHRH peaks, there was no correlation between GH and GHRH or GH and SRIH. NPY levels in the CSF fluctuated episodically at 2.03-hour intervals. GH pulse peaks occurred 0–30 min after NPY troughs, and there was a significant negative cross-correlation and negative synchronicity between GH and NPY profiles. In addition, intracerobroventricular infusion of NPY suppressed GH secretagogue (KP102)-induced GH release. Conclusion: The periodic decrease in NPY may be involved in the generation of GH pulsatility in goats.
Variability of End-Expiratory Lung Volume in Premature Infants
Authors: Emeriaud Guillaume , Baconnier Pierre , Eberhard André , Debillon Thierry , Calabrese Pascale , Benchetrit Gila
Published: May 2010

Background: Analysis of breath-to-breath variability of respiratory characteristics provides information on the respiratory control. In infants, the control of end-expiratory lung volume (EELV) is active and complex, and it can be altered by respiratory disease. The pattern of EELV variability may reflect the behavior of this regulatory system. Objectives: We aimed to characterize EELV variability in premature infants, and to evaluate variability pattern changes associated with respiratory distress and ventilatory support. Methods: EELV variations were recorded using inductance plethysmography in 18 infants (gestational age 30–33 weeks) during the first 10 days of life. An autocorrelation analysis was conducted to evaluate the ‘EELV memory’, i.e. the impact of the characteristics of one breath on the following breaths. Results: In infants without respiratory symptoms, EELV variability was high, with large standard deviations of EELV. Autocorrelation was found to be significant until a median lag of 7 (interquartiles: 4–8) breaths. Autocorrelation was markedly prolonged in patients with respiratory distress or ventilatory support, with a higher number of breath lags with significant autocorrelation (p < 0.01) and higher autocorrelation coefficients (p < 0.05). Conventional assisted ventilation does not re-establish a healthy EELV profile and is associated with lower respiratory variability. Conclusions: In premature infants, EELV variability pattern is modified by respiratory distress with a prolonged ‘EELV memory’, which suggests a greater instability of the control of EELV.