bluuebunny/crossref_metadata_2025 huggingface dataset:
Invariant polygons in systems with grazing-sliding
Authors: Szalai R. , Osinga H. M.
Published: June 2008

The paper investigates generic three-dimensional nonsmooth systems with a periodic orbit near grazing-sliding. We assume that the periodic orbit is unstable with complex multipliers so that two dominant frequencies are present in the system. Because grazing-sliding induces a dimension loss and the instability drives every trajectory into sliding, the system has an attractor that consists of forward sliding orbits. We analyze this attractor in a suitably chosen Poincaré section using a three-parameter generalized map that can be viewed as a normal form. We show that in this normal form the attractor must be contained in a finite number of lines that intersect in the vertices of a polygon. However the attractor is typically larger than the associated polygon. We classify the number of lines involved in forming the attractor as a function of the parameters. Furthermore, for fixed values of parameters we investigate the one-dimensional dynamics on the attractor.
Hysteresis of ionization waves
Authors: Dinklage A. , Bruhn B. , Testrich H. , Wilke C.
Published: June 2008

A quasi-logistic, nonlinear model for ionization wave modes is introduced. Modes are due to finite size of the discharge and current feedback. The model consists of competing coupled modes and it incorporates spatial wave amplitude saturation. The hysteresis of wave mode transitions under current variation is reproduced. Sidebands are predicted by the model and found in experimental data. The ad hoc model is equivalent to a general—so-called universal—approach from bifurcation theory.
Simulations of atmospheric pressure discharge in a high-voltage nanosecond pulse using the particle-in-cell Monte Carlo collision model in noble gases
Authors: Shi Feng , Wang Dezhen , Ren Chunsheng
Published: June 2008

Atmospheric pressure discharge nonequilibrium plasmas have been applied to plasma processing with modern technology. Simulations of discharge in pure Ar and pure He gases at one atmospheric pressure by a high voltage trapezoidal nanosecond pulse have been performed using a one-dimensional particle-in-cell Monte Carlo collision (PIC-MCC) model coupled with a renormalization and weighting procedure (mapping algorithm). Numerical results show that the characteristics of discharge in both inert gases are very similar. There exist the effects of local reverse field and double-peak distributions of charged particles’ density. The electron and ion energy distribution functions are also observed, and the discharge is concluded in the view of ionization avalanche in number. Furthermore, the independence of total current density is a function of time, but not of position.
Three-state conical intersections in cytosine and pyrimidinone bases
Authors: Kistler Kurt A. , Matsika Spiridoula
Published: June 2008

Three-state conical intersections have been located and characterized for cytosine and its analog 5-methyl-2-pyrimidinone using multireference configuration-interaction ab initio methods. The potential energy surfaces for each base contain three different three-state intersections: two different S0-S1-S2 intersections (gs∕ππ*∕nNπ* and gs∕ππ*∕nOπ*) and an S1-S2-S3 intersection (ππ*∕nNπ*∕nOπ*). Two-state seam paths from these intersections are shown to be connected to previously reported two-state conical intersections. Nonadiabatic coupling terms have been calculated, and the effects of the proximal third state on these quantities are detailed. In particular, it is shown that when one of these loops incorporates more than one seam point, there is a profound and predictable effect on the phase of the nonadiabatic coupling terms, and as such provides a diagnostic for the presence and location of additional seams. In addition, it is shown that each of the three three-state conical intersections located on cytosine and 5-methyl-2-pyrimidinone is qualitatively similar between the two bases in terms of energies and character, implying that, like with the stationary points and two-state conical intersections previously reported for these two bases, there is an underlying pattern of energy surfaces for 2-pyrimidinone bases, in general, and this pattern also includes three-state conical intersections.
Photoluminescence characteristics of quantum dots with electronic states interconnected along growth direction
Authors: Kojima Osamu , Nakatani Hiroaki , Kita Takashi , Wada Osamu , Akahane Kouichi , Tsuchiya Masahiro
Published: June 2008

We report the excitonic photoluminescence (PL) characteristics in multiple stacked quantum dots (QDs) fabricated by using a strain compensating technique. The PL characteristics of QD excitons vary according to the spacer layer thickness; with decreasing spacer layer thickness, the PL intensity decreases and the PL decay time becomes longer. Furthermore, the intensity ratio of the transverse-magnetic to transverse-electric modes in the PL emission from the cleaved edge surface increases. As the spacer layer thickness decreases, the degree of overlap of the electron envelope functions owing to tunneling becomes larger, which consequently interconnects the QDs along the growth direction. This interconnection induces a large change in the oscillator strength of the QD excitons and the PL characteristics. Therefore, we concluded that the optical characteristics can be controlled drastically by changing the spacer layer thickness.
Pr
3
+
photoluminescence in ferroelectric (Ba0.77Ca0.23)TiO3 ceramics: Sensitive to polarization and phase transitions
Authors: Zhang Pengzhan , Shen Mingrong , Fang Liang , Zheng Fengang , Wu Xinglong , Shen Jiancang , Chen Haitai
Published: June 2008

We reported in this study that the photoluminescence (PL) spectra of (Ba0.77Ca0.23)TiO3:Pr3+ were sensitive to both polarization and phase transitions of the ferroelectric ceramics. Comparing with the unpoled sample, all the red emissions under different temperatures of 50to300K increase about 30% for the poled 0.1mol% Pr3+-doped ceramic. Obvious peaks around 100K for the red and blue emission intensities of Pr3+ ions were found when the ceramic passed through the orthorhombic-tetragonal phase transition, and a step decrease in the red emission intensity occurs around the tetragonal-cubic transition. Both polarization and phase transition effects on the Pr3+ PL were ascribed to local environmental changes of Pr3+ ions in the (Ba0.77Ca0.23)TiO3 ceramic.
Interferometric method for determining the sum of the flexoelectric coefficients (e1+e3) in an ionic nematic material
Authors: Trabi C. L. , Brown C. V. , Smith A. A. T. , Mottram N. J.
Published: June 2008

The time-dependent periodic distortion profile in a nematic liquid crystal phase grating has been measured from the displacement of tilt fringes in a Mach–Zehnder interferometer. A 0.2Hz squarewave voltage was applied to alternate stripe electrodes in an interdigitated electrode geometry. The time-dependent distortion profile is asymmetric with respect to the polarity of the applied voltage and decays with time during each half period due to ionic shielding. This asymmetry in the response allows the determination of the sum of the flexoelectric coefficients (e1+e3) using nematic continuum theory since the device geometry does not possess inherent asymmetry.
CuO three-dimensional flowerlike nanostructures: Controlled synthesis and characterization
Authors: Zhang Xia , Guo Yong-Gang , Liu Wei-Min , Hao Jing-Cheng
Published: June 2008

CuO three-dimensional (3D) flowerlike nanostructures were successfully synthesized on copper surface by a simple solution method. CuO nanostructure was systematically studied by scanning electron microscopy, transmission electron microscopy, x-ray powder diffraction, and x-ray photoelectron spectrum. The factors to control the morphology and size of the CuO nanostructures were explored, showing that the reaction time and the concentration of starting regents play important roles in the formation of the CuO 3D nanostructures.
Increase in indium diffusion by tetrafluoromethane plasma treatment and its effects on the device performance of polymer light-emitting diodes
Authors: Jo Sung Jin , Kim Chang Su , Kim Jong Bok , Ryu Seung Yoon , Noh Joo Hyon , Baik Hong Koo , Kim Youn Sang , Lee Se-Jong
Published: June 2008

The effects of tetrafluoromethane (CF4) plasma treatment of indium-tin-oxide (ITO) anode on indium diffusion into a poly(3,4-ethylene dioxythiophene):poly(styrene sulphonate) (PEDOT:PSS) layer were studied. Auger electron spectroscopy (AES) depth profile showed that 0.2at.% indium was present in the PEDOT:PSS layer when ITO was not plasma treated. The plasma treatment of ITO increased the indium concentration to ∼6at.%. The increase in indium can be explained by an oxygen deficiency in the CF4 plasma treated ITO. The presence of indium in the PEDOT:PSS layer showed a correlation with performance degradation of polymer light-emitting diodes.
Acute carbon dioxide avoidance in
Caenorhabditis elegans
Authors: Hallem Elissa A. , Sternberg Paul W.
Published: June 2008

Carbon dioxide is produced as a by-product of cellular respiration by all aerobic organisms and thus serves for many animals as an important indicator of food, mates, and predators. However, whether free-living terrestrial nematodes such as
Caenorhabditis elegans
respond to CO
2
was unclear. We have demonstrated that adult
C. elegans
display an acute avoidance response upon exposure to CO
2
that is characterized by the cessation of forward movement and the rapid initiation of backward movement. This response is mediated by a cGMP signaling pathway that includes the cGMP-gated heteromeric channel TAX-2/TAX-4. CO
2
avoidance is modulated by multiple signaling molecules, including the neuropeptide Y receptor NPR-1 and the calcineurin subunits TAX-6 and CNB-1. Nutritional status also modulates CO
2
responsiveness via the insulin and TGFβ signaling pathways. CO
2
response is mediated by a neural circuit that includes the BAG neurons, a pair of sensory neurons of previously unknown function. TAX-2/TAX-4 function in the BAG neurons to mediate acute CO
2
avoidance. Our results demonstrate that
C. elegans
senses and responds to CO
2
using multiple signaling pathways and a neural network that includes the BAG neurons and that this response is modulated by the physiological state of the worm.
Characterization of endogenous human Argonautes and their miRNA partners in RNA silencing
Authors: Azuma-Mukai Asuka , Oguri Hideo , Mituyama Toutai , Qian Zhi Rong , Asai Kiyoshi , Siomi Haruhiko , Siomi Mikiko C.
Published: June 2008

Small RNAs triggering RNA silencing are loaded onto Argonautes and then sequence-specifically guide them to target transcripts. Epitope-tagged human Argonautes (hAgo1, hAgo2, hAgo3, and hAgo4) are associated with siRNAs and miRNAs, but only epitope-tagged hAgo2 has been shown to have Slicer activity. Contrarily, how endogenous hAgos behave with respect to small RNA association and target RNA destruction has remained unclear. Here, we produced monoclonal antibodies for individual hAgos. High-throughput pyrosequencing revealed that immunopurified endogenous hAgo2 and hAgo3 associated mostly with miRNAs. Endogenous hAgo3 did not show Slicer function but localized in P-bodies, suggesting that hAgo3 endogenously expressed is, like hAgo2, involved in the miRNA pathway but antagonizes the RNAi activity of hAgo2. Sequence variations of miRNAs were found at both 5′ and 3′ ends, suggesting that multiple mature miRNAs containing different “seed” sequences can arise from one miRNA precursor. The hAgo antibodies we raised are valuable tools for ascertaining the functional behavior of endogenous Argonautes and miRNAs in RNA silencing.
Protein 4.1R-dependent multiprotein complex: New insights into the structural organization of the red blood cell membrane
Authors: Salomao Marcela , Zhang Xihui , Yang Yang , Lee Soohee , Hartwig John H. , Chasis Joel Anne , Mohandas Narla , An Xiuli
Published: June 2008

Protein 4.1R (4.1R) is a multifunctional component of the red cell membrane. It forms a ternary complex with actin and spectrin, which defines the nodal junctions of the membrane-skeletal network, and its attachment to the transmembrane protein glycophorin C creates a bridge between the protein network and the membrane bilayer. We now show that deletion of 4.1R in mouse red cells leads to a large diminution of actin accompanied by extensive loss of cytoskeletal lattice structure, with formation of bare areas of membrane. Whereas band 3, the preponderant transmembrane constituent, and proteins known to be associated with it are present in normal or increased amounts, glycophorin C is missing and XK, Duffy, and Rh are much reduced in the 4.1R-deficient cells. The inference that these are associated with 4.1R was borne out by the results of
in vitro
pull-down assays. Furthermore, whereas Western blot analysis showed normal levels of band 3 and Kell, flow cytometric analysis using an antibody against the extracellular region of band 3 or Kell revealed reduction of these two proteins, suggesting a conformational change of band 3 and Kell epitopes. Taken together, we suggest that 4.1R organizes a macromolecular complex of skeletal and transmembrane proteins at the junctional node and that perturbation of this macromolecular complex not only is responsible for the well characterized membrane instability but may also remodel the red cell surface.
A voltage-sensing phosphatase, Ci-VSP, which shares sequence identity with PTEN, dephosphorylates phosphatidylinositol 4,5-bisphosphate
Authors: Iwasaki Hirohide , Murata Yoshimichi , Kim Youngjun , Hossain Md. Israil , Worby Carolyn A. , Dixon Jack E. , McCormack Thomas , Sasaki Takehiko , Okamura Yasushi
Published: June 2008

Phosphatidylinositol lipids play diverse physiological roles, and their concentrations are tightly regulated by various kinases and phosphatases. The enzymatic activity of
Ciona intestinalis
voltage sensor-containing phosphatase (Ci-VSP), recently identified as a member of the PTEN (phosphatase and tensin homolog deleted on chromosome 10) family of phosphatidylinositol phosphatases, is regulated by its own voltage-sensor domain in a voltage-dependent manner. However, a detailed mechanism of Ci-VSP regulation and its substrate specificity remain unknown. Here we determined the
in vitro
substrate specificity of Ci-VSP by measuring the phosphoinositide phosphatase activity of the Ci-VSP cytoplasmic phosphatase domain. Despite the high degree of identity shared between the active sites of PTEN and Ci-VSP, Ci-VSP dephosphorylates not only the PTEN substrate, phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P
3
], but also, unlike PTEN, phosphatidylinositol 4,5-bisphosphate [PI(4,5)P
2
]. Enzymatic action on PI(4,5)P
2
removes the phosphate at position 5 of the inositol ring, resulting in the production of phosphatidylinositol 4-phosphate [PI(4)P]. The active site Cys-X
5
-Arg (CX
5
R) sequence of Ci-VSP differs with that of PTEN only at amino acid 365 where a glycine residue in Ci-VSP is replaced by an alanine in PTEN. Ci-VSP with a G365A mutation no longer dephosphorylates PI(4,5)P
2
and is not capable of inducing depolarization-dependent rundown of a PI(4,5)P
2
-dependent potassium channel. These results indicate that Ci-VSP is a PI(3,4,5)P
3
/PI(4,5)P
2
phosphatase that uniquely functions in the voltage-dependent regulation of ion channels through regulation of PI(4,5)P
2
levels.
Eps15 Mediates Vesicle Trafficking from thetrans-Golgi Network via an Interaction with the Clathrin Adaptor AP-1
Authors: Chi Susan , Cao Hong , Chen Jing , McNiven Mark A.
Published: June 2008

Eps15 (EGFR pathway substrate clone 15) is well known for its role in clathrin-coated vesicle formation at the plasma membrane through interactions with other clathrin adaptor proteins such as AP-2. Interestingly, we observed that in addition to its plasma membrane localization, Eps15 is also present at the trans-Golgi network (TGN). Therefore, we predicted that Eps15 might associate with clathrin adaptor proteins at the TGN and thereby mediate the formation of Golgi-derived vesicles. Indeed, we have found that Eps15 and the TGN clathrin adaptor AP-1 coimmunoprecipitate from rat liver Golgi fractions. Furthermore, we have identified a 14-amino acid motif near the AP-2–binding domain of Eps15 that is required for binding to AP-1, but not AP-2. Disruption of the Eps15–AP-1 interaction via siRNA knockdown of AP-1 or expression of mutant Eps15 protein, which lacks a 14-amino acid motif representing the AP-1 binding site of Eps15, significantly reduced the exit of secretory proteins from the TGN. Together, these findings indicate that Eps15 plays an important role in clathrin-coated vesicle formation not only at the plasma membrane but also at the TGN during the secretory process.
Characterization of Class I and II ADP-Ribosylation Factors (Arfs) in Live Cells: GDP-bound Class II Arfs Associate with the ER-Golgi Intermediate Compartment Independently of GBF1
Authors: Chun Justin , Shapovalova Zoya , Dejgaard Selma Y. , Presley John F. , Melançon Paul
Published: June 2008

Despite extensive work on ADP-ribosylation factor (Arf) 1 at the Golgi complex, the functions of Arf2–5 in the secretory pathway, or for that of any Arf at the ER-Golgi intermediate compartment (ERGIC) remain uncharacterized. Here, we examined the recruitment of fluorescently tagged Arf1, -3, -4, and -5 onto peripheral ERGIC. Live cell imaging detected Arfs on peripheral puncta that also contained Golgi-specific brefeldin A (BFA) resistance factor (GBF) 1 and the ERGIC marker p58. Unexpectedly, BFA did not promote corecruitment of Arfs with GBF1 either at the Golgi complex or the ERGIC, but it uncovered striking differences between Arf1,3 and Arf4,5. Although Arf1,3 quickly dissociated from all endomembranes after BFA addition, Arf4,5 persisted on ERGIC structures, even after redistribution of GBF1 to separate compartments. The GDP-arrested Arf4(T31N) mutant localized to the ERGIC, even with BFA and Exo1 present. In addtion, loss of Arf · GTP after treatment with Exo1 caused rapid release of all Arfs from the Golgi complex and led to GBF1 accumulation on both Golgi and ERGIC membranes. Our results demonstrate that GDP-bound Arf4,5 associate with ERGIC membranes through binding sites distinct from those responsible for GBF1 recruitment. Furthermore, they provide the first evidence that GBF1 accumulation on membranes may be caused by loss of Arf · GTP, rather than the formation of an Arf · GDP · BFA · GBF1 complex.
Application of dynamic factor analysis in the assessment of Iberian anglerfish stocks
Authors: Azevedo Manuela , Duarte Rafael , Cardador Fátima , Sousa Pedro , Fariña Celso , Sampedro Paz , Landa Jorge , Costas Gersom
Published: June 2008

Azevedo, M., Duarte, R., Cardador, F., Sousa, P., Fariña, C., Sampedro, P., Landa, J., and Costas, G. 2008. Application of dynamic factor analysis in the assessment of Iberian anglerfish stocks. – ICES Journal of Marine Science, 65: 1362–1369. Dynamic factor analysis (DFA) was applied to six time-series of catch per unit effort data of the Iberian (ICES Divisions VIIIc and IXa) white anglerfish (Lophius piscatorius) and black anglerfish (L. budegassa). Results showed that grouping the abundance indices reflected the fleet's area of exploitation and fish size selection. Two common trends (CTs) were extracted for each species, capturing the main signal of abundance over time. The white anglerfish was assessed using these CTs as input to the biomass dynamic model currently used in the ICES assessment, to investigate whether the approach would reduce the uncertainty in parameter estimates and related quantities. Using the CTs, bias estimates are lower. The current perception of an overexploited stock is unchanged, but a much lower intrinsic rate of biomass increase was estimated, indicating that the biomass recovery might be much slower. A lower maximum sustainable yield, ∼3600 t, was obtained, and this is more consistent with the historical landings trajectory. The application of DFA to stock assessment of anglerfish, presented here for the first time, can be extended to age-based assessments.
TheRPi-mcd1Locus fromSolanum microdontumInvolved in Resistance toPhytophthora infestans, Causing a Delay in Infection, Maps on Potato Chromosome4in a Cluster of NBS-LRR Genes
Authors: Tan M. Y. Adillah , Hutten Ronald C. B. , Celis Carolina , Park Tae-Ho , Niks Rients E. , Visser Richard G. F. , van Eck Herman J.
Published: June 2008

The distinction between field resistance and resistance based on resistance (R) genes has been proven valid for many plant–pathogen interactions. This distinction does not seem to be valid for the interaction between potato and late blight. In this study, a locus involved in late blight resistance, derived from Solanum microdontum, provides additional evidence for this lack of distinction. The resistance is associated with a hypersensitive response and results in a delay of infection of approximately 1 to 2 weeks. Both a quantitative as well as a qualitative genetic approach were used, based on data from a field assay. Quantitative trait locus (QTL) analysis identified a QTL on chromosome 4 after correction of the resistance data for plant maturity. A qualitative genetic analysis resulted in the positioning of this locus on the short arm of chromosome 4 in between amplified fragment length polymorphism marker pCTmACG_310 and cleaved amplified polymorphic sequence markers TG339 and T0703. This position coincides with a conserved Phytophthora R gene cluster which includes R2, R2-like, RPi-blb3, and RPi-abpt. This implies that RPi-mcd1is the fifth R gene of this nucleotide-binding site leucine-rich repeat cluster. The implications of our results on R-gene-based and field resistance are discussed.
Aggression, sex and individual differences in cerebral lateralization in a cichlid fish
Authors: Reddon Adam R , Hurd Peter L
Published: June 2008

Cerebral lateralization is an evolutionarily ancient adaptation, apparently ubiquitous among vertebrates. Despite demonstrated advantages of having a more lateralized brain, substantial variability in the strength of lateralization exists within most species. The underlying reasons for the maintenance of this variation are largely unknown. Here, we present evidence that the strength of lateralization is linked to a behavioural trait, aggressiveness, in the convict cichlid (
Archocentrus nigrofasciatus
), and that this relationship depends on the sex of the fish. This finding suggests that individual variation in behaviour may be linked to variation in cerebral lateralization, and must be studied with regard to the sex of the animal.
Biological switches and clocks
Authors: Tyson John J , Albert Reka , Goldbeter Albert , Ruoff Peter , Sible Jill
Published: June 2008

To introduce this special issue on biological switches and clocks, we review the historical development of mathematical models of bistability and oscillations in chemical reaction networks. In the 1960s and 1970s, these models were limited to well-studied biochemical examples, such as glycolytic oscillations and cyclic AMP signalling. After the molecular genetics revolution of the 1980s, the field of molecular cell biology was thrown wide open to mathematical modellers. We review recent advances in modelling the gene–protein interaction networks that control circadian rhythms, cell cycle progression, signal processing and the design of synthetic gene networks.
To fly or not to fly: high flight costs in a large sea duck do not imply an expensive lifestyle
Authors: Pelletier David , Guillemette Magella , Grandbois Jean-Marc , Butler Patrick J
Published: June 2008

A perennial question in ornithology is whether flight has evolved mostly to facilitate access to food or as an anti-predator strategy. However, flight is an expensive mode of locomotion and species using flight regularly are associated with an expensive lifestyle. Using heart rate (HR) data loggers implanted in 13 female common eiders (Somateria mollissima), our objective was to test the hypothesis that a high level of flight activity increases their energy budget. We used the long-term recording (seven months) of HR as an index of energy expenditure and the HR flight signature to compile all flight events. Our results indicate that the eider is one of the thriftiest volant birds with only 10 minutes of flight time per day. Consequently, we were not able to detect any effect of flight activity on their energy budget despite very high flight costs (123–149 W), suggesting that flight was controlled by energy budget limitations. However, the low flight activity of that species may also be related to their prey landscape requiring few or no large-scale movements. Nevertheless, we suggest that the (fitness) benefits of keeping flight ability in this species exceed the costs by allowing a higher survival in relation to predation and environmental harshness.
Critical opalescence points to thermodynamic instability: relevance to small-angle X-ray scattering of resorcinol–formaldehyde gel formation at low pH
Authors: Gommes Cedric J. , Job Nathalie , Pirard Jean-Paul , Blacher Silvia , Goderis Bart
Published: June 2008

During the formation at low pH of resorcinol–formaldehyde gels with a structure in the micrometre range, small-angle X-ray scattering exhibits a non-monotonic intensity variation as a function of reaction time. The data are analyzed in terms of scattering by statistical fluctuations of polymer concentration, the amplitude of which is maximal close to the critical point for phase separation between polymer and solvent. The data do not carry any morphological information, but they unambiguously show that the driving force of the gel formation is a thermodynamic instability of the polymerizing solution.
Testing whether productivity mediates the occurrence of alternate stable states and assembly cycles in a model microcosm system
Authors: Fox Jeremy W.
Published: June 2008

When do initial conditions, which reflect the assembly history of a community, affect the final community state? Comparative field studies and recent theory suggest that initial conditions matter at high productivity, because uninvasible alternate stable states and assembly cycles are more likely at high productivity. However, this prediction and the mechanisms behind it have not been tested experimentally. An alternative hypothesis is that initial conditions are relatively unimportant, and that communities generally are comprised of species with appropriate traits, which might vary with productivity. I assembled communities of protists and rotifers in laboratory microcosms from a species‐rich, trophically‐diverse species pool using all possible combinations of two initial conditions and four productivity levels. After communities approached their final states, invasions by the species that initially failed to persist tested the invasibility of those final states and tested for assembly cycles. I also examined how local (within‐microcosm) diversity and regional diversity (total species richness of all microcosms of a given productivity level) varied with productivity. Comparative field work has used such scale‐dependent diversity–productivity relationships as evidence for effects of assembly history. Productivity had a modest effect on final pre‐invasion species composition, while initial conditions had a very weak effect. Most invasions failed, and the frequency of successful invasions and of post‐invasion extinctions did not vary with productivity. Instead, species that were present most frequently pre‐invasion were also the most successful invaders, and the least‐likely species to go extinct post‐invasion. Local and regional richness did not vary substantially with productivity. Overall, the results suggest that final communities are predictably comprised of species with appropriate traits, and are not an unpredictable outcome of initial conditions.
Gene expression profiling of diffuse large B‐cell lymphoma supervised by CD21 expression
Authors: Miyazaki Kana , Yamaguchi Motoko , Suguro Miyuki , Choi Woonyoung , Ji Yuan , Xiao Lianchun , Zhang Wei , Ogawa Shoko , Katayama Naoyuki , Shiku Hiroshi , Kobayashi Tohru
Published: June 2008

This study investigated the gene expression profiles of 40 cases of diffuse large B‐cell lymphoma (DLBCL) according to CD21 expression, a favourable prognostic factor in DLBCL. Signature genes were analysed by Gene Ontology Tree Machine, and genes concerned with the immune system and related categories were significantly upregulated in CD21− DLBCLs. Of 40 DLBCLs, four were germinal centre B cell‐like (GCB) and 36 non‐GCB. Of the 36 non‐GCB DLBCLs, 14 CD21+ DLBCLs showed significantly better overall survival than the 22 CD21− DLBCLs (P = 0·036). Hierarchical cluster analysis of signature genes related to CD21 was applied to previously published data sets, resulting in two groups for each data set, CD21+ type DLBCLs and CD21− type DLBCLs. Survival of CD21+ type DLBCLs was significantly better than that of CD21– type (P = 0·006 and P = 0·004, respectively). In both data sets, CD21+ type DLBCLs predominantly included GCB DLBCLs compared with CD21− type. The top classifier gene of CD21 expression was IGHM, and the five of nine Gene Ontology categories significant in CD21– DLBCLs included IGHM. Immunohistochemical analysis of 216 DLBCLs confirmed that overall survival of surface (s) IgM+ DLBCLs was significantly poorer than that of sIgM‐ DLBCLs (P = 0·013).
BCR‐ABL1‐induced expression of HSPA8 promotes cell survival in chronic myeloid leukaemia
Authors: José‐Enériz Edurne San , Román‐Gómez José , Cordeu Lucia , Ballestar Esteban , Gárate Leire , Andreu Enrique J. , Isidro Isabel , Guruceaga Elizabeth , Jiménez‐Velasco Antonio , Heiniger Anabel , Torres Antonio , Calasanz Maria José , Esteller Manel , Gutiérrez Norma C. , Rubio Angel , Pérez‐Roger Ignacio , Agirre Xabier , Prósper Felipe
Published: June 2008

In order to determine new signal transduction pathways implicated in chronic myeloid leukaemia (CML), we performed a gene expression profile comparison between CD34+ cells from CML patients and healthy donors. Functional studies were performed using the Mo7e and Mo7e‐p210 cell lines. Expression of CCND1 (Cyclin D1), as well as the chaperone HSPA8, which is important for regulation of CCND1, were significantly upregulated in CD34+ CML cells. Upregulation of HSPA8 was dependent, at least in part, on STAT5 (signal transducer and activator of transcrition 5)‐dependent transcriptional activation, as demonstrated by chromatin immunoprecipitation. The presence of HSPA8 in the nuclear protein fraction as well as its binding to CCND1 suggests that it may contribute to stabilization of the CCND1/CDK4 complex, which, in turn, may participate in proliferation of CML cells. Treatment of CML cells with the specific HSPA8 inhibitor 15‐deoxyspergualin induced inhibition of CML cell viability but did not induce apoptosis. In conclusion, our studies suggest that STAT5‐mediated activation of HSPA8 induces nuclear translocation and activation of the CCND1/CDK4 complex leading to increased proliferation of CML cells, deciphering a new pathway implicated in CML and supporting a potential role of chaperone inhibitors in the treatment of CML.
Overtreatment in threshold and developed countries
Authors: Reading Richard
Published: June 2008

.
 
Frey B.
(
2008
)

,
93
,
260
–
263
.
 
DOI: 10.1136/adc.2007.124479
.
Risk of immune thrombocytopenic purpura after measles‐mumps‐rubella immunization in children
Authors: Reading Richard
Published: June 2008

.
 
France E. K.,
Glanz J.,
Xu S.,
Hambidge S.,
Yamasaki K.,
Black S. B.,
Marcy M.,
Mullooly J. P.,
Jackson L. A.,
Nordin J.,
Belongia E. A.,
Hohman K.,
Chen R. T. &
Davis R.
,
for the Vaccine Safety Datalink Team
(
2008
)

,
121
,
e687
–
e692
.
 
DOI: 10.1542/peds.2007‐1578
.

Background  The measles‐mumps‐rubella vaccine has been associated with immune thrombocytopenia purpura in two small studies.

Methods  By using the Vaccine Safety Datalink, we identified measles‐mumps‐rubella‐vaccinated children aged 1 to 18 years. A case of immune thrombocytopenia purpura was defined as a patient with a platelet count of ≤50 000/µL with clinical bleeding and normal red and white blood cell indices. The immune thrombocytopenia purpura incidence rates during exposed (42 days after vaccination) and unexposed time periods were determined. A retrospective cohort of vaccinated children was used to determine incident rate ratios for children aged 1 to 18 years, 12 to 23 months and 12 to 15 months.

Results  A total of 1 036 689 children received 1 107 814 measles‐mumps‐rubella vaccinations; there were 259 confirmed patients with immune thrombocytopenia purpura. Because only five exposed cases occurred after age 2 years, analyses were limited to children aged 12 to 23 months. Exposed patients aged 12 to 23 months had lower median platelet counts than those who were unexposed and had similar median duration of illness (11 vs. 10 days). The incident rate ratio was highest for children aged 12 to 15 months at 7.10. The incident rate ratio for boys aged 12 to 15 months was 14.59, and the incident rate ratio for girls in the same age group was 3.22. Seventy‐six per cent of immune thrombocytopenia purpura cases in children aged 12 to 23 months were attributable to measles‐mumps‐rubella vaccination. This vaccine causes one case of immune thrombocytopenia purpura per every 40 000 doses.

Conclusion  Measles‐mumps‐rubella vaccine that is given in the second year of life is associated with an increased risk of immune thrombocytopenia purpura.
Consistent geographic structure among multiple nuclear sequences and cpDNA polymorphisms of Cardamine nipponica Franch. et Savat. (Brassicaceae)
Authors: IKEDA HAJIME , SENNI KEI , FUJII NORIYUKI , SETOGUCHI HIROAKI
Published: June 2008

Molecular phylogeography has inferred the history of differentiation between regions and/or among populations following the Pleistocene climatic oscillations, mostly based on the genetic structure of organelle DNA. However, such genetic structure only reflects the history of a single gene, and studies based on single‐copy genes of nuclear DNA (nDNA) are required for phylogeography, although their efficiency remains unclear. To examine the utility of nDNA loci, the genetic structures of three genes from Cardamine nipponica, which is closely related to the model species Arabidopsis thaliana, were elucidated: the nDNA genes DET1, PHYA, PHYE, as well as chloroplast DNA (cpDNA). In 279 individuals collected from throughout the range of the species, strong genetic differentiation between northern and central Japan was found for all loci. This result suggested that populations in central Japan experienced a different history from those in northern Japan during the Pleistocene climatic oscillations. In addition, the evidence of refugia at the edges of the distribution, where the genetic structure was less influenced by colonization following range expansion, was shown for several loci. The specific genetic structure within the southernmost populations of northern Japan suggested that this region was also isolated during range expansion. Hence, the consistent history among loci and a more detailed history from several loci indicated that cpDNA can represent the history of vicariance and demonstrated the efficiency of single‐copy nuclear genes in phylogeography.
Staged approach for abdominal wound closure following combined liver and intestinal transplantation from living donors in pediatric patients
Authors: Grevious Mark A. , Iqbal Ronak , Raofi Vandad , Beatty Elizabeth , Oberholzer Jose’ , Cohen Mimis , Abcarian Herand , Testa Giuliano , Benedetti Enrico
Published: June 2008

Abstract:  Primary closure of the abdominal wall after combined liver and intestine transplantation from a living donor into a pediatric patient is usually not possible, because of the size of the donor organ, graft edema, and preexisting scars or stomas of the abdominal wall. Closure under tension may lead to abdominal compartment syndrome with vascular compromise and necrosis of the transplanted organ. We describe our experience of abdominal wound closure after liver and intestinal transplant in the pediatric patient using a staged approach. From February 2003 to June 2006, we managed five pediatric liver and intestinal living donor transplant recipients. Because of the large post‐transplantation abdominal wall defect, a staged technique of abdominal wound closure was utilized. Initially, an absorbable Polygalactin mesh was sutured around the layer of the defect. As soon as adequate granulation tissue was formed over the mesh a STSG was applied. From the wound stand point all five patients were managed successfully with staged wound closure after transplantation. Granulation tissue filled and covered the mesh within 7.6 wk. A STSG was then used to cover the defect. All infants recovered well and none had a significant wound complication in the immediate post‐operative period following STSG. At a mean follow‐up of 24 months only one patient developed an entero‐cutaneous fistula five months post‐transplant. Staged abdominal wall coverage with the use of Polygalactin mesh followed by STSG is a simple and effective technique. A closed wound is achieved in a timely fashion with protection of the viscera. Residual ventral hernia will need to be managed in the future with one of several reconstructive techniques.
Benzo‐thiadiazole‐7‐carbothioic Acid S‐methyl Ester does not protect Melon Fruits against Fusarium pallidoroseum Infection but Induces Defence Responses in Melon Seedlings
Authors: Gondim Darcy M. F. , Terao Daniel , Martins‐Miranda Aparecida S. , Vasconcelos Iika M. , Oliveira José T. A.
Published: June 2008

The present study investigated the potential of benzo‐thiadiazole‐7‐carbothioic acid S‐methyl ester (BTH) to protect postharvest melons var. ‘Orange Flesh’ from the fruit rot caused by Fusarium pallidoroseum. It was noticed that melon fruits immersed in BTH and postinoculated with the fungus presented the same pattern of disease incidence/severity and activity of the defence‐related enzymes superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, phenylalanine ammonia‐lyase, and β‐1,3‐glucanase of controls, indicating that BTH was ineffective in protecting melons from the fruit rot disease. However, the preflowering application of BTH in melon seedlings induced stunted growth, probably related to enhanced lignification which is related to the plant cell wall reinforcement and increase of resistance against invading pathogens, and alterations of the activity of the studied defence‐related enzymes in comparison with controls, suggesting that this strategy could probably be effective for the control of the postharvest rot of melon fruits through activation of systemic resistance.
Formation and Germination of Septoria tritici Secondary Conidia as Affected by Environmental Factors
Authors: Guo Jian‐Rong , Verreet Joseph‐Alexander
Published: June 2008

The effects of medium, isolate, temperature, light and pH on the formation and germination of Septoria tritici secondary conidia were tested. Of the six media tested, the malt–yeast extract agar was the best and generated 1.82 × 109 conidia/plate. The ten isolates tested showed different ability of conidia production. Darkness significantly reduced conidial formation and enhanced the transition of intermediates. The conidial germination and germ tube growth was strongly inhibited at 30°C. The suitable pH for conidial budding in malt–yeast broth (MYB) was between 5 and 9. At pH 2, 10 and 11, almost no new conidia were formed. The number of conidia reached 1.27 × 108 conidia/ml after 7 days in MYB, significantly more than that in potato dextrose broth, wheat leaf extract and H2O.
Expression and Activity of Steroid Sulphatase in the Boar Testis
Authors: Mutembei HM , Kowalewski MP , Ugele B , Schuler G , Hoffmann B
Published: June 2008

Contents

Oestrogens are essential for male fertility targeting the testicular‐epididymal compartment. However, the underlying mechanisms are only vaguely known and species specificities must be considered. The boar has a remarkably high testicular‐oestrogen output, with the biologically inactive oestrone‐sulphate being the major oestrogen occurring in the testicular vein. In the boar testis and epididymis, activity of steroid sulphatase (StS) and oestrogen sulphotransferase has been demonstrated. Thus apart from their synthesis in Leydig cells, provision of biologically active free oestrone seems also to depend on the activity and localization of these enzymes. Our aim was to establish expression patterns and activity of StS in boar testis. Testes were randomly collected from healthy boars and allotted to five age groups, five animals in each, aged 50, 100, 150, 200 and 250 days. Three extra boars aged over 250 days were castrated to obtain fresh tissue for enzyme activity tests. Immunohistochemistry detected StS only in the cytoplasm of Leydig cells and – except for day‐50 group in which 65.1 ± 4.9% (X ± SD) of the cells were positive – expression was constant with virtually all the cells staining positive. RT‐PCR and in situ hybridization confirmed expression and localization of StS mRNA. The Vmax and Km value (X ± SD) for StS was 24.05 ± 0.3 fmol/s/μg protein and 2.15 ± 0.12 μm. These data suggest that StS within the Leydig cells of the boar is involved in modulation of testicular oestrogen bioavailability and that the site of sulpho‐conjugation is not the testis but a different compartment of the testes–epididymidis complex.
Rapid changes in hippocampal CA1 pyramidal cell function via pre‐ as well as postsynaptic membrane mineralocorticoid receptors
Authors: Olijslagers J. E. , De Kloet E. R. , Elgersma Y. , Van Woerden G. M. , Joëls M. , Karst H.
Published: June 2008

Corticosterone (100 nm) rapidly increases the frequency of miniature excitatory postsynaptic currents in mouse CA1 pyramidal neurons via membrane‐located mineralocorticoid receptors (MRs). We now show that a presynaptic ERK1/2 signalling pathway mediates the nongenomic effect, as it was blocked by the MEK inhibitors U0126 (10 µm) and PD098059 (40 µm) and occluded in H‐RasG12V‐mutant mice with constitutive activation of the ERK1/2 presynaptic pathway. Notably, the increase in mEPSC frequency was not mediated by retrograde signalling through endocannabinoids or nitric oxide, supporting presynaptic localization of the signalling pathway. Unexpectedly, corticosterone was also found to have a direct postsynaptic effect, rapidly decreasing the peak amplitude of IA currents. This effect takes place via postsynaptic membrane MRs coupled to a G protein‐mediated pathway, as the effect of corticosterone on IA was effectively blocked by 0.5 mm GDP‐β‐S administered via the recording pipette into the postsynaptic cell. Taken together, these results indicate that membrane MRs mediate rapid, nongenomic effects via pre‐ as well as postsynaptic pathways. Through these dual pathways, high corticosterone concentrations such as occur after stress could contribute to enhanced CA1 pyramidal excitability.
Dopamine modulates diurnal and circadian rhythms of protein phosphorylation in photoreceptor cells of mouse retina
Authors: Pozdeyev Nikita , Tosini Gianluca , Li Li , Ali Fatima , Rozov Stanislav , Lee Rehwa H. , Iuvone P. Michael
Published: June 2008

Many aspects of photoreceptor metabolism are regulated as diurnal or circadian rhythms. The nature of the signals that drive rhythms in mouse photoreceptors is unknown. Dopamine amacrine cells in mouse retina express core circadian clock genes, leading us to test the hypothesis that dopamine regulates rhythms of protein phosphorylation in photoreceptor cells. To this end we investigated the phosphorylation of phosducin, an abundant photoreceptor‐specific phosphoprotein. In mice exposed to a daily light–dark cycle, robust daily rhythms of phosducin phosphorylation and retinal dopamine metabolism were observed. Phospho‐phosducin levels were low during the daytime and high at night, and correlated negatively with levels of the dopamine metabolite 3,4‐dihydroxyphenylacetic acid. The effect of light on phospho‐phosducin levels was mimicked by pharmacological activation of dopamine D4 receptors. The amplitude of the diurnal rhythm of phospho‐phosducin was reduced by > 50% in D4 receptor‐knockout mice, due to higher daytime levels of phospho‐phosducin. In addition, the daytime level of phospho‐phosducin was significantly elevated by L‐745,870, a dopamine D4 receptor antagonist. These data indicate that dopamine and other light‐dependent processes cooperatively regulate the diurnal rhythm of phosducin phosphorylation. Under conditions of constant darkness a circadian rhythm of phosducin phosphorylation was observed, which correlated negatively with the circadian rhythm of 3,4‐dihydroxyphenylacetic acid levels. The circadian fluctuation of phospho‐phosducin was completely abolished by constant infusion of L‐745,870, indicating that the rhythm of phospho‐phosducin level is driven by dopamine. Thus, dopamine release in response to light and circadian clocks drives daily rhythms of protein phosphorylation in photoreceptor cells.
The medial nucleus of the trapezoid body in rat: spectral and temporal properties vary with anatomical location of the units
Authors: Tolnai Sandra , Hernandez Olga , Englitz Bernhard , Rübsamen Rudolf , Malmierca Manuel S.
Published: June 2008

The medial nucleus of the trapezoid body (MNTB) is a distinct nucleus in the superior olivary complex that transforms excitatory input from the cochlear nucleus into a widespread inhibitory output to distinct auditory brainstem nuclei. Few studies have dealt with the response properties of MNTB neurons to sound stimulation using in vivo preparations. In order to have a better understanding of the functional significance of the MNTB in auditory processing we report the basic temporal and spectral response properties of its principal cells using single‐unit extracellular recordings to acoustic stimulation with pure tones and amplitude‐modulated stimuli in the rat. Ninety‐seven per cent of units showed V‐shaped frequency response areas. Rate level functions were mainly saturating (51%) or monotonic (45%) at high intensities. Post‐stimulus time histograms typically were characterised as primary‐like with notch (59%) or primary‐like (33%). Units showed good phase‐locking to sinusoidally amplitude‐modulated signals with vector strength VS values up to 0.87. Modulation transfer functions had low‐pass shapes at near‐threshold levels, with cut‐off frequencies ranging from 370 to 1270 Hz. Exploration of the relationship between the temporal and spectral properties and the location of the units in the MNTB yielded characteristic frequency (CF)‐dependent response properties (latency, Q10 and cut‐off frequency) following a medio‐lateral gradient, and CF‐independent response features (maximum firing rate) following a dorso‐ventral gradient.