bluuebunny/crossref_metadata_2025 huggingface dataset:
Stability of Taylor–Couette flow in a finite-length cavity with radial throughflow
Authors: Serre Eric , Sprague Michael A. , Lueptow Richard M.
Published: March 2008

Linear stability analysis predicts that a radial throughflow in a Taylor–Couette system will alter the stability of the flow, but the underlying physics for the stabilization of the flow is unclear. We investigate the impact of radial inflow and outflow on Taylor vortex flow and wavy vortex flow in a finite-length cavity via direct numerical simulation using a three-dimensional spectral method. The numerical simulations are consistent with linear stability predictions in that radial inflow and strong radial outflow have a stabilizing effect, while weak radial outflow destabilizes the system slightly. A small radial outflow velocity enhances the strength of the Taylor vortices resulting in destabilization of the base flow, whereas strong radial outflow and radial inflow reduce vortex strength, thus stabilizing the system. The transition to wavy vortex flow is unaffected by small radial outflow, but is stabilized for radial inflow. For strong radial outflow the wavy vortex flow includes localized dislocations in the vortex structure.
Thermal conductivity of plutonium above room temperature
Authors: Alexander C. A. , Wood Van E.
Published: March 2008

The thermal diffusivity of plutonium metal has been measured from room temperature to 822K by the laser-flash method, and the thermal conductivity has been calculated using literature data for the other parameters. Linear fits of the conductivity to temperature have been provided for all the phases with the exception of δ′. A simple quadratic fit, suitable for rough estimates, for all the higher-temperature phases other than δ′ is also given. The results are compared with measurements of the electrical resistivity in the same region, and are discussed in terms of contemporary theories of the electronic structure of the material in its various phases.
Abrupt self-termination of vertically aligned carbon nanotube growth
Authors: Meshot Eric R. , Hart A. John
Published: March 2008

Real-time height measurements demonstrate that growth of millimeter-high carbon nanotube (CNT) forests terminates abruptly after first exhibiting a steady decay in growth rate. Termination is accompanied by a distinct loss of alignment among the CNTs, which is quantified by small-angle x-ray scattering. Previously suggested diffusion-limited and decay-limited models of kinetics accurately fit the growth period, yet fail to capture the termination behavior and incorrectly predict that growth will continue for much longer durations than observed. It appears that structural disorder is a distinct chemical and/or mechanical signature of self-terminated CNT forest growth.
Rovibrational spectroscopy and intramolecular dynamics of 1,2-trans-d2-ethene in the first CH stretch overtone region
Authors: Zwielly Amir , Portnov Alexander , Levi Chen , Rosenwaks Salman , Bar Ilana
Published: March 2008

The first overtone region of the CH stretching vibration of 1,2-trans-d2-ethene (HDCCDH) was monitored via jet-cooled action spectroscopy and room temperature photoacoustic spectroscopy. The spectra include a strong band, which we assigned as the ν1+ν9 CH stretch vibration, and five additional bands related to transitions to coupled states. The spectral features were modeled in terms of a six-state deperturbation analysis, revealing the energies of the zero-order states and the relatively strong couplings between the initially excited ν1+ν9 state and the doorway states. Considering these energies and the fundamental frequencies of 1,2-trans-d2-ethene and presuming that only low-order resonances are involved in the couplings enabled the assignment of the states. The analysis also allowed obtaining insight on energy flow and to find out that the energy oscillations between the CH stretch state and the doorway states occur on a subpicosecond time scale.
Perturbation of spin-valve nanowire reference layers during domain wall motion induced by nanosecond-long current pulses
Authors: Thomas Luc , Hayashi Masamitsu , Jiang Xin , Rettner Charles , Parkin Stuart S. P.
Published: March 2008

The depinning of domain walls from notches in spin-valve (SV) nanowires induced by nanosecond-long current pulses is probed by giant magnetoresistance. The current densities needed to depin domain walls at low field can be so large that significant Joule heating may be observed for pulses even as short as 1ns. The reference layers in the SV, which are formed from highly stable artificial antiferromagnetic layers, can be so strongly perturbed that the resistance of the SV is no longer a reliable indicator of the domain wall’s position.
Investigation of the benzene-dimer potential energy surface: DFT/CCSD(T) correction scheme
Authors: Bludský Ota , Rubeš Miroslav , Soldán Pavel , Nachtigall Petr
Published: March 2008

A novel method, designated as the density functional theory/coupled-cluster with single and double and perturbative triple excitation [DFT/CCSD(T)] correction scheme, was developed for precise calculations of weakly interacting sp2 hydrocarbon molecules and applied to the benzene dimer. The DFT/CCSD(T) interaction energies are in excellent agreement with the estimated CCSD(T)/complete basis set interaction energies. The tilted T-shaped structure having Cs symmetry was determined to be a global minimum on the benzene-dimer potential energy surface (PES), approximately 0.1kcal∕mol more stable than the parallel-displaced structure. A fully optimized set of ten stationary points on the benzene-dimer PES is proposed for the evaluation of the reliability of methods for the description of weakly interacting systems.
Sensitivity optimization of the scanning microdeformation microscope and application to mechanical characterization of soft materials
Authors: Le Rouzic J. , Vairac P. , Cretin B. , Delobelle P.
Published: March 2008

In this article we present the study of the sensitivity optimization of our system of micromechanical characterization called the scanning microdeformation microscope. The flexural contact modes of vibration of the cantilever have been modeled. We discuss the matching between the cantilever stiffness and the contact stiffness which depends on the sample material. In order to obtain the best sensitivity, the stiffnesses must be the closest one to each other. Because the length of the cantilever directly affects its stiffness, the cantilever geometry can be optimized for different materials. We have validated this study with measurements on a soft material the polydimethylsiloxane with a cantilever optimized for materials of Young’s moduli of some megapascals. Experimental results obtained with two different samples have shown the high sensitivity of the method for the measurement of low Young’s moduli and have been compared with nanoindentation and dynamic mechanical analysis results.
Extraction of radiative and nonradiative rates in Sb based midwave infrared lasers using a novel approach
Authors: Lobad Ahmed I. , Pease E. A. , Dawson L. R. , Krishna Sanjay , Vern Schlie L. A.
Published: March 2008

We developed a technique using nonlinear correlation of photoluminescence (PL) to characterize midwave infrared lasers by extracting the density and temperature dependence of the carrier lifetime and its exact branching into radiative and nonradiative processes. This was accomplished, without time resolving the PL recovery, through mathematical optimization. We extracted this information by using a laser source that can be operated in both continuous-wave and short pulse modes. Through fitting of the PL signal and its nonlinear correlation for both laser modes of operation, the carrier lifetime as a function of density is extracted. As a proof of principle, we investigated a midinfrared Sb based laser and showed that the radiative branching ratio drops from ∼54% at 80K to about 3% at room temperature, resulting from an order of magnitude increase in the nonradiative rate coupled with a factor of 2 reduction in the radiative rate. We believe that this is a very generic approach and can be extended to various luminescing material systems.
Eigenmode mediated excitation and radiation in a planar microcavity
Authors: Dukin A. A. , Feoktistov N. A. , Grudinkin S. A. , Medvedev A. V. , Pevtsov A. B. , Golubev V. G. , Centini M. , Sibilia C.
Published: March 2008

We studied the effect of planar microcavity eigenmodes on the optical excitation efficiency and the luminescence of emission centers (erbium ions) introduced in the active layer of the microcavity structure. We show experimentally that, if pumping conditions are chosen in order to excite the microcavity eigenmode, the emission intensity from erbium ions is enhanced by an order of magnitude compared to the case of pumping via excitation of photonic band states. The observed photoluminescence enhancement was theoretically and quantitatively estimated by analyzing the overlap integral between the distribution profiles of the electromagnetic fields inside the active layer of the microcavity.
Feasibility of quantitative determination of local optical absorbances in tissue-mimicking phantoms using acousto-optic sensing
Authors: Bratchenia A. , Molenaar R. , Kooyman R. P. H.
Published: March 2008

We have investigated the application of ultrasound modulation of coherent light for quantitative determination of local absorbances in tissue-mimicking phantoms. An Intralipid-based phantom model, which mimics a blood vessel in human tissue, was used. The detection technique was based on homodyne parallel speckle detection in transmission mode. Based on a comparison of experimental data and Monte Carlo simulations, a quantitative correlation between local absorbances of the phantom and the measured signal has been shown. The use of microsecond pulses of ultrasound and laser light resulted in a spatial resolution of the system of a few millimeters.
Systematics and phylogeny of Chrysomelobia species (Acari:Podapolipidae), sexually transmitted parasites of chrysomelid beetles
Authors: Seeman Owen D.
Published: March 2008

Chrysomelobia Regenfuss and Parobia Seeman & Nahrung are sexually transmitted mites, the former being parasites of chrysomelid beetles in the Americas, Europe and Africa, the latter a radiation on the Paropsini (Chrysomelidae) in Australia. A cladistic analysis of Chrysomelobia and Parobia shows the type species of Chrysomelobia, C. mahunkai Regenfuss, is placed within Parobia. Therefore, Parobia is synonymised with Chrysomelobia, which has priority. I describe another nine new species of Chrysomelobia from Australian paropsine beetles: C. aquariolus, sp. nov., C. orthagoriscus, sp. nov. and C. cubile, sp. nov. from Paropsis porosa Erichson; C. lipsettae, sp. nov. from Dicranosterna pedestris (Chapuis); C. armstrongi, sp. nov. from Paropsisterna sp. nr minerva (Blackburn); C. pagurus, sp. nov. from Paropsis charybdis Stål; and C. nahrungae, sp. nov., C. vafer, sp. nov. and C. verecundus, sp. nov. from three species of Trachymela. Chrysomelobia captivus (Seeman & Nahrung) is recorded from Paropsisterna nobilitata (Erichson) for the first time. Most Australian members of Chrysomelobia are host-specific and beetles may host up to three mite species. Within species-groups of mites, species that share the same host genus are closely related. However, mite species that share the same host species are usually from different species-groups of mites. Although these patterns suggest co-speciation at terminal nodes and host transfers at deeper nodes, little can be made of these patterns without a host phylogeny. Keys to Chrysomelobia adults are provided.
Pachybolini - a tribe of giant Afrotropical millipedes: arguments for monophyly and the description of a new genus from Madagascar (Diplopoda:Spirobolida:Pachybolidae)
Authors: Wesener Thomas , Enghoff Henrik , Wägele Johann-Wolfgang
Published: March 2008

Madabolus, gen. nov. is described to accommodate M. maximus, sp. nov. (type species) from several localities in western Madagascar. A phylogenetic analysis of 26 spirobolidan taxa, based on morphological characters, places Madabolus, gen. nov. with the Afrotropical genera Pelmatojulus de Saussure, 1860; Pachybolus Cook, 1897; Hadrobolus Cook, 1897 and Epibolus Cook, 1897. The tribe Pachybolini is proposed to include Madabolus, gen. nov. and the four abovementioned genera. Putative autapomorphies of Pachybolini are: a closed incisura lateralis; setae of gnathochilarial lamella lingualis apical; vulva kidney- or crescent-shaped, with valves meeting in a sinuous fissure and crest protruding. Within Pachybolini, Pelmatojulus (West Africa) stands out by virtue of an increased number of apical antennal sensory cones, with great probability an apomorphy. Madabolus, gen. nov. and east African genera of the tribe share another potential synapomorphy, namely, an increased number of setae on the gnathochilarial lamellae linguales. Other Malagasy genera of Pachybolidae do not seem to be related to Afrotropical genera.
Trace element fractionation processes in resuspended mineral aerosols extracted from Australian continental surface materials
Authors: Moreno Teresa , Amato Fulvio , Querol Xavier , Alastuey Andrés , Gibbons Wes
Published: March 2008

Unconsolidated surface soil and dust samples of varying trace element (TE) content were collected from remote locations in central and south-eastern Australia. The finer grained fraction of the samples (<10 µm, PM10) was separated and geochemically compared to the parent particulate matter (PMPAR). TE are mostly hosted in phosphates and oxides/hydroxides or adsorbed to clay minerals, and are normally fractionated into the PM10, producing PM10/PMPAR ratios >1, especially in siliceous, TE-depleted dusts. In contrast, samples TE-enriched by primary silicate minerals eroded from igneous and metamorphic rocks can produce PM10/PMPAR <1 for more mobile elements such as K, Na, Ba, Rb, and Sr. K/Rb is normally lower in PM10 (unless the PMPAR is muscovite-rich) as is the light/heavy rare earth elements (LREE/HREE) ratio because both Rb and HREE are preferentially adsorbed by fine clay particles. Zr and Hf are mostly hosted by zircon crystals initially >10 µm but these diminish in size with time and sedimentological transport so that PM10 aerosol concentrations of these elements are typically telescoped into a narrower range than the PMPAR. Nb is strongly fractionated into PM10, with Nb/TiO2 ratios characteristic of the durable host mineral rutile in all but the most TE-enriched PM. TE content of PM10 in continental dusts is controlled by both physical and chemical processes. Fresh primary silicates suppress PM10/PMPAR ratios of TE with low ionic potential, whereas the opposite effect is induced by hydraulic sorting and/or physical attrition during surface transport, as well as clay absorbtion and fixation of TE in small, resistant accessory minerals.
Comparison of solid-state 13C NMR spectra of soil organic matter from an experimental burning site acquired at two field strengths
Authors: Smernik Ronald J. , Eckmeier Eileen , Schmidt Michael W. I.
Published: March 2008

Solid-state 13C cross polarisation (CP) nuclear magnetic resonance spectra were acquired for 15 soil organic matter samples on 2 different spectrometers (200 MHz and 400 MHz). Distributions of broad functional group classes—carboxyl, aryl, O-alkyl, and alkyl—were determined by integration across broad chemical shift regions. The distributions derived from the 2 spectrometers were closely correlated (r2 = 0.77–0.93). Only slight biases were identified; carboxyl C contents were on average 8% lower and alkyl C contents 5% higher for spectra acquired on the 400 MHz spectrometer. These results indicate that valid 13C CP spectra can be acquired at field strengths up to 400 MHz, and that spectra acquired at different field strengths can be directly comparable.
Active tails enhance arboreal acrobatics in geckos
Authors: Jusufi Ardian , Goldman Daniel I. , Revzen Shai , Full Robert J.
Published: March 2008

Geckos are nature's elite climbers. Their remarkable climbing feats have been attributed to specialized feet with hairy toes that uncurl and peel in milliseconds. Here, we report that the secret to the gecko's arboreal acrobatics includes an active tail. We examine the tail's role during rapid climbing, aerial descent, and gliding. We show that a gecko's tail functions as an emergency fifth leg to prevent falling during rapid climbing. A response initiated by slipping causes the tail tip to push against the vertical surface, thereby preventing pitch-back of the head and upper body. When pitch-back cannot be prevented, geckos avoid falling by placing their tail in a posture similar to a bicycle's kickstand. Should a gecko fall with its back to the ground, a swing of its tail induces the most rapid, zero-angular momentum air-righting response yet measured. Once righted to a sprawled gliding posture, circular tail movements control yaw and pitch as the gecko descends. Our results suggest that large, active tails can function as effective control appendages. These results have provided biological inspiration for the design of an active tail on a climbing robot, and we anticipate their use in small, unmanned gliding vehicles and multisegment spacecraft.
Ischemic preconditioning blocks BAD translocation, Bcl-x
L
cleavage, and large channel activity in mitochondria of postischemic hippocampal neurons
Authors: Miyawaki Takahiro , Mashiko Toshihiro , Ofengeim Dimitry , Flannery Richard J. , Noh Kyung-Min , Fujisawa Sho , Bonanni Laura , Bennett Michael V. L. , Zukin R. Suzanne , Jonas Elizabeth A.
Published: March 2008

Transient forebrain or global ischemia induces delayed neuronal death in vulnerable CA1 pyramidal cells with many features of apoptosis. A brief period of ischemia, i.e., ischemic preconditioning, affords robust protection of CA1 neurons against a subsequent more prolonged ischemic challenge. Here we show that preconditioning acts via PI3K/Akt signaling to block the ischemia-induced cascade involving mitochondrial translocation of Bad, assembly of Bad with Bcl-x
L
, cleavage of Bcl-x
L
to form its prodeath fragment, ΔN-Bcl-x
L
, activation of large-conductance channels in the mitochondrial outer membrane, mitochondrial release of cytochrome
c
and Smac/DIABLO (second mitochondria-derived activator of caspases/direct IAP-binding protein with low pI), caspase activation, and neuronal death. These findings show how preconditioning acts to prevent the release of cytochrome
c
and Smac/DIABLO from mitochondria and to preserve the integrity of the mitochondrial membrane. The specific PI3K inhibitor LY294002 administered
in vivo
1 h before or immediately after ischemia or up to 120 h later significantly reverses preconditioning-induced protection, indicating a requirement for sustained PI3K signaling in ischemic tolerance. These findings implicate PI3K/Akt signaling in maintenance of the integrity of the mitochondrial outer membrane.
Tackling the Anglophones’ free ride
Authors: Parijs Philippe Van
Published: March 2008

In science and in all other domains that require communication across borders, we need one lingua franca, and this lingua franca will be English. The adoption of the native language of some as everyone’s lingua franca unavoidably raises a problem of justice in various senses. One of these is cooperative justice, the fair distribution of the cost of producing a public good. This article proposes a criterion of fair burden sharing — proportionality of cost to benefit — and explores its policy implications.

Does this criterion require a linguistic tax on the native speakers of the lingua franca in order to subsidize the learning of it by all others? If so, how high should the subsidy be, and should it be pitched at the same per capita level for all learning communities? If not, is there an alternative way of implementing a fair compensation for the free riding of lingua franca natives on everyone else’s learning?

Among the article’s conclusions are that fair subsidies would need to be directed disproportionately to the Chinese — even abstracting from possible differences in the difficulty of learning English — and that more hopes should be focused on the compensatory poaching of the web than on anything resembling a linguistic tax.
Protolanguage in ontogeny and phylogeny
Authors: Greenfield Patricia M. , Lyn Heidi , Savage-Rumbaugh E. Sue
Published: March 2008

We approach the issue of holophrasis versus compositionality in the emergence of protolanguage by analyzing the earliest combinatorial constructions in child, bonobo, and chimpanzee: messages consisting of one symbol combined with one gesture. Based on evidence from apes learning an interspecies visual communication system and children acquiring a first language, we conclude that the potential to combine two different kinds of semiotic element — deictic and representational — was fundamental to the protolanguage forming the foundation for the earliest human language. This is a form of compositionality, in that each communicative element stands for a single semantic element. The conclusion that human protolanguage was exclusively holophrastic — containing a proposition in a single word — emerges only if one considers the symbol alone, without taking into account the gesture as a second element comprising the total message.
From metonymy to syntax in the communication of events
Authors: Dessalles Jean-Louis
Published: March 2008

A modular analysis of spontaneous language use provides support for the existence of an identifiable step in language evolution, protolanguage. Our suggestion is that a grammarless form of expression would have evolved to signal unexpected events, a behavior still prevalent in our species. Words could not be so specific as to refer to whole, non-recurring, situations. They referred to elements such as objects or locations, and the communicated event was inferred metonymically. Compositionality was achieved, without syntax, through multi-metonymy, as words referring to elements of the same situation were concatenated into proto-utterances.
Holophrastic protolanguage
Authors: Tallerman Maggie
Published: March 2008

This paper challenges recent assumptions that holophrastic utterances could be planned, processed, stored and retrieved from storage, focussing on three specific issues: (i) Problems in conceptual planning of multi-proposition utterances of the type proposed by Arbib (2005), Mithen (2005); (ii) The question of whether holophrastic protolanguage could have been processed by a special ‘holistic’ mode, the precursor to a projected ‘idiom mode’ in modern language; (iii) The implications for learning a holophrastic proto-lexicon in light of lexical constraints on word learning. Modern speakers only plan utterances in clause-sized units, and it is improbable that protolanguage speakers had more complex abilities. Moreover, the production and comprehension of idioms sheds no light on a putative ‘holistic’ mode of language processing, since idioms are not processed in this way. Finally, innate constraints on learning lexical items preclude the types of word meanings proposed by proponents of holophrastic protolanguage.
Growth points from the very beginning
Authors: McNeill David , Duncan Susan D. , Cole Jonathan , Gallagher Shaun , Bertenthal Bennett
Published: March 2008

Early humans formed language units consisting of global and discrete dimensions of semiosis in dynamic opposition, or ‘growth points.’ At some point, gestures gained the power to orchestrate actions, manual and vocal, with significances other than those of the actions themselves, giving rise to cognition framed in dual terms. However, our proposal emphasizes natural selection of joint gesture-speech, not ‘gesture-first’ in language origin.
But how did protolanguage actually start?
Authors: Bickerton Derek
Published: March 2008

In dealing with the nature of protolanguage, an important formative factor in its development, and one that would surely have influenced that nature, has too often been neglected: the precise circumstances under which protolanguage arose. Three factors are involved in this neglect: a failure to appreciate radical differences between the functions of language and animal communication, a failure to relate developments to the overall course of human evolution, and the supposition that protolanguage represents a package, rather than a series of separate developments that sequentially impacted the communication of pre-humans. An approach that takes these factors into account is very briefly suggested.
Orchestration of the S-phase and DNA damage checkpoint pathways by replication forks from early origins
Authors: Caldwell Julie M. , Chen Yinhuai , Schollaert Kaila L. , Theis James F. , Babcock George F. , Newlon Carol S. , Sanchez Yolanda
Published: March 2008

The S-phase checkpoint activated at replication forks coordinates DNA replication when forks stall because of DNA damage or low deoxyribonucleotide triphosphate pools. We explore the involvement of replication forks in coordinating the S-phase checkpoint using dun1Δ cells that have a defect in the number of stalled forks formed from early origins and are dependent on the DNA damage Chk1p pathway for survival when replication is stalled. We show that providing additional origins activated in early S phase and establishing a paused fork at a replication fork pause site restores S-phase checkpoint signaling to chk1Δ dun1Δ cells and relieves the reliance on the DNA damage checkpoint pathway. Origin licensing and activation are controlled by the cyclin–Cdk complexes. Thus, oncogene-mediated deregulation of cyclins in the early stages of cancer development could contribute to genomic instability through a deficiency in the forks required to establish the S-phase checkpoint.
As functional nuclear actin comes into view, is it globular, filamentous, or both?
Authors: Pederson Thoru
Published: March 2008

The idea that actin may have an important function in the nucleus has undergone a rapid transition from one greeted with skepticism to a now rapidly advancing research field. Actin has now been implicated in transcription by all three RNA polymerases, but the structural form it adopts in these processes remains unclear. Recently, a claim was made that monomeric nuclear actin plays a role in signal transduction, while a just-published study of RNA polymerase I transcription has implicated polymeric actin, consorting with an isoform of its classical partner myosin. Both studies are critically discussed here, and although there are several issues to be resolved, it now seems reasonable to start thinking about functions for both monomeric and assembled actin in the nucleus.
Shuttling of the chaperones Unc45b and Hsp90a between the A band and the Z line of the myofibril
Authors: Etard Christelle , Roostalu Urmas , Strähle Uwe
Published: March 2008

The formation of thick filaments in striated muscle involves the chaperones Hsp90a and Unc45. We show that Unc45b and Hsp90a, two zebrafish orthologues, colocalize with myosin during myofibrillogenesis and associate with the Z line when myofibril assembly is completed. In response to stress or damage to the myofiber, Unc45b and Hsp90a dissociate from the Z line and transiently associate with myosin. Although chaperone activity of Unc45b requires the full-length protein, only the central and Unc45-Cro1p-She4p domains are required to anchor it to the Z line, and multiple subdomains mediate association with nascent myosin. We propose that the Z line serves as a reservoir for chaperones, allowing a rapid mobilization in response to muscle damage. Our data are consistent with a differential affinity model as an explanation for the shuttling of the chaperones between the Z line and myosin.
Polyomavirus BK with rearranged noncoding control region emerge in vivo in renal transplant patients and increase viral replication and cytopathology
Authors: Gosert Rainer , Rinaldo Christine H. , Funk Georg A. , Egli Adrian , Ramos Emilio , Drachenberg Cinthia B. , Hirsch Hans H.
Published: March 2008

Immunosuppression is required for BK viremia and polyomavirus BK–associated nephropathy (PVAN) in kidney transplants (KTs), but the role of viral determinants is unclear. We examined BKV noncoding control regions (NCCR), which coordinate viral gene expression and replication. In 286 day–matched plasma and urine samples from 129 KT patients with BKV viremia, including 70 with PVAN, the majority of viruses contained archetypal (ww-) NCCRs. However, rearranged (rr-) NCCRs were more frequent in plasma than in urine samples (22 vs. 4%; P < 0.001), and were associated with 20-fold higher plasma BKV loads (2.0 × 104/ml vs. 4.4 × 105/ml; P < 0.001). Emergence of rr-NCCR in plasma correlated with duration and peak BKV load (R2 = 0.64; P < 0.001). This was confirmed in a prospective cohort of 733 plasma samples from 227 patients. For 39 PVAN patients with available biopsies, rr-NCCRs were associated with more extensive viral replication and inflammation. Cloning of 10 rr-NCCRs revealed diverse duplications or deletions in different NCCR subregions, but all were sufficient to increase early gene expression, replication capacity, and cytopathology of recombinant BKV in vitro. Thus, rr-NCCR BKV emergence in plasma is linked to increased replication capacity and disease in KTs.
The Th17–ELR+ CXC chemokine pathway is essential for the development of central nervous system autoimmune disease
Authors: Carlson Thaddeus , Kroenke Mark , Rao Praveen , Lane Thomas E. , Segal Benjamin
Published: March 2008

The ELR+ CXC chemokines CXCL1 and CXCL2 are up-regulated in the central nervous system (CNS) during multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). However, their functional significance and the pathways regulating their expression are largely unknown. We show that transfer of encephalitogenic CD4+ Th17 cells is sufficient to induce CXCL1 and CXCL2 transcription in the spinal cords of naive, syngeneic recipients. Blockade or genetic silencing of CXCR2, a major receptor for these chemokines in mice, abrogates blood–brain barrier (BBB) breakdown, CNS infiltration by leukocytes, and the development of clinical deficits during the presentation as well as relapses of EAE. Depletion of circulating polymorphonuclear leukocytes (PMN) had a similar therapeutic effect. Furthermore, injection of CXCR2+ PMN into CXCR2−/− mice was sufficient to restore susceptibility to EAE. Our findings reveal that a Th17–ELR+ CXC chemokine pathway is critical for granulocyte mobilization, BBB compromise, and the clinical manifestation of autoimmune demyelination in myelin peptide–sensitized mice, and suggest new therapeutic targets for diseases such as MS.
Roles of GRK and PDE4 Activities in the Regulation of β2 Adrenergic Signaling
Authors: Xin Wenkuan , Tran Tuan M. , Richter Wito , Clark Richard B. , Rich Thomas C.
Published: March 2008

An important focus in cell biology is understanding how different feedback mechanisms regulate G protein–coupled receptor systems. Toward this end we investigated the regulation of endogenous β2 adrenergic receptors (β2ARs) and phosphodiesterases (PDEs) by measuring cAMP signals in single HEK-293 cells. We monitored cAMP signals using genetically encoded cyclic nucleotide-gated (CNG) channels. This high resolution approach allowed us to make several observations. (a) Exposure of cells to 1 μM isoproterenol triggered transient increases in cAMP levels near the plasma membrane. Pretreatment of cells with 10 μM rolipram, a PDE4 inhibitor, prevented the decline in the isoproterenol-induced cAMP signals. (b) 1 μM isoproterenol triggered a sustained, twofold increase in phosphodiesterase type 4 (PDE4) activity. (c) The decline in isoproterenol-dependent cAMP levels was not significantly altered by including 20 nM PKI, a PKA inhibitor, or 3 μM 59-74E, a GRK inhibitor, in the pipette solution; however, the decline in the cAMP levels was prevented when both PKI and 59-74E were included in the pipette solution. (d) After an initial 5-min stimulation with isoproterenol and a 5-min washout, little or no recovery of the signal was observed during a second 5-min stimulation with isoproterenol. (e) The amplitude of the signal in response to the second isoproterenol stimulation was not altered when PKI was included in the pipette solution, but was significantly increased when 59-74E was included. Taken together, these data indicate that either GRK-mediated desensitization of β2ARs or PKA-mediated stimulation of PDE4 activity is sufficient to cause declines in cAMP signals. In addition, the data indicate that GRK-mediated desensitization is primarily responsible for a sustained suppression of β2AR signaling. To better understand the interplay between receptor desensitization and PDE4 activity in controlling cAMP signals, we developed a mathematical model of this system. Simulations of cAMP signals using this model are consistent with the experimental data and demonstrate the importance of receptor levels, receptor desensitization, basal adenylyl cyclase activity, and regulation of PDE activity in controlling cAMP signals, and hence, on the overall sensitivity of the system.
Luminal Ca2+ Regulation of Single Cardiac Ryanodine Receptors: Insights Provided by Calsequestrin and its Mutants
Authors: Qin Jia , Valle Giorgia , Nani Alma , Nori Alessandra , Rizzi Nicoletta , Priori Silvia G. , Volpe Pompeo , Fill Michael
Published: March 2008

The luminal Ca2+ regulation of cardiac ryanodine receptor (RyR2) was explored at the single channel level. The luminal Ca2+ and Mg2+ sensitivity of single CSQ2-stripped and CSQ2-associated RyR2 channels was defined. Action of wild-type CSQ2 and of two mutant CSQ2s (R33Q and L167H) was also compared. Two luminal Ca2+ regulatory mechanism(s) were identified. One is a RyR2-resident mechanism that is CSQ2 independent and does not distinguish between luminal Ca2+ and Mg2+. This mechanism modulates the maximal efficacy of cytosolic Ca2+ activation. The second luminal Ca2+ regulatory mechanism is CSQ2 dependent and distinguishes between luminal Ca2+ and Mg2+. It does not depend on CSQ2 oligomerization or CSQ2 monomer Ca2+ binding affinity. The key Ca2+-sensitive step in this mechanism may be the Ca2+-dependent CSQ2 interaction with triadin. The CSQ2-dependent mechanism alters the cytosolic Ca2+ sensitivity of the channel. The R33Q CSQ2 mutant can participate in luminal RyR2 Ca2+ regulation but less effectively than wild-type (WT) CSQ2. CSQ2-L167H does not participate in luminal RyR2 Ca2+ regulation. The disparate actions of these two catecholaminergic polymorphic ventricular tachycardia (CPVT)–linked mutants implies that either alteration or elimination of CSQ2-dependent luminal RyR2 regulation can generate the CPVT phenotype. We propose that the RyR2-resident, CSQ2-independent luminal Ca2+ mechanism may assure that all channels respond robustly to large (>5 μM) local cytosolic Ca2+ stimuli, whereas the CSQ2-dependent mechanism may help close RyR2 channels after luminal Ca2+ falls below ∼0.5 mM.
Complete manifolds with nonnegative curvature operator
Authors: Ni Lei , Wu Baoqiang
Published: March 2008

In this short note, as a simple application of the strong result proved recently by Böhm and Wilking, we give a classification on closed manifolds with

2
2

-nonnegative curvature operator. Moreover, by the new invariant cone constructions of Böhm and Wilking, we show that any complete Riemannian manifold (with dimension

≥
3

\ge 3

) whose curvature operator is bounded and satisfies the pinching condition

R
≥
δ

tr
⁡
(
R
)

2
n
(
n
−
1
)

I

>
0

R\ge \delta \frac {\operatorname {tr}(R)}{2n(n-1)} \mathrm {I}>0

, for some

δ
>
0

\delta >0

, must be compact. This provides an intrinsic analogue of a result of Hamilton on convex hypersurfaces.
𝑞-Eulerian polynomials: Excedance number and major index
Authors: Shareshian John , Wachs Michelle
Published: March 2008

In this research announcement we present a new

q
q

-analog of a classical formula for the exponential generating function of the Eulerian polynomials. The Eulerian polynomials enumerate permutations according to their number of descents or their number of excedances. Our

q
q

-Eulerian polynomials are the enumerators for the joint distribution of the excedance statistic and the major index. There is a vast literature on

q
q

-Eulerian polynomials that involves other combinations of Eulerian and Mahonian permutation statistics, but this is the first result to address the combination of excedance number and major index. We use symmetric function theory to prove our formula. In particular, we prove a symmetric function version of our formula, which involves an intriguing new class of symmetric functions. We also discuss connections with (1) the representation of the symmetric group on the homology of a poset introduced by Björner and Welker; (2) the representation of the symmetric group on the cohomology of the toric variety associated with the Coxeter complex of the symmetric group, studied by Procesi, Stanley, Stembridge, Dolgachev, and Lunts; (3) the enumeration of words with no adjacent repeats studied by Carlitz, Scoville, and Vaughan and by Dollhopf, Goulden, and Greene; and (4) Stanley’s chromatic symmetric functions.
Jacquet modules of 𝑝-adic general linear groups
Authors: Jantzen Chris
Published: March 2008

In this paper, we study Jacquet modules for

p
p

-adic general linear groups. More precisely, we have results—formulas and algorithms—aimed at addressing the following question: Given the Langlands data for an irreducible representation, can we determine its (semisimplified) Jacquet module? We use our results to answer this question in a number of cases, as well as to recover some familiar results as relatively easy consequences.
Celestial3D: a novel method for 3D visualization of familial data
Authors: Loh Angeline M. , Wiltshire Steven , Emery Jon , Carter Kim W. , Palmer Lyle J.
Published: March 2008

Summary: Traditional two-dimensional (2D) software programs for drawing pedigrees are limited when dealing with extended pedigrees. In successive generations, the number of individuals grows exponentially, leading to an unworkable amount of space required in the horizontal direction for 2D displays. In addition, it is not always possible to place closely related individuals near each other due to the lack of space in 2Ds. To address these issues we have developed three-dimensional (3D) pedigree drawing techniques to enable clearer visualization of extended pedigrees. Currently no other methods are available for displaying extended pedigrees in 3Ds. We have made freely available a software tool—‘Celestial3D’—that implements these novel techniques.

Availability: Freely available to non-commercial users

Contact:  celestial3d@genepi.org.au

Supplementary information:  www.genepi.org.au/celestial3d
Going against the flow: how marine invasions spread and persist in the face of advection1
Authors: Byers James E. , Pringle James M.
Published: March 2008

Byers J. E., and Pringle J. M. 2008. Going against the flow: how marine invasions spread and persist in the face of advection. – ICES Journal of Marine Science, 65: 723–724.
Achromobacter xylosoxidans subsp. xylosoxidans prosthetic aortic valve infective endocarditis and aortic root abscesses
Authors: van Hal S. , Stark D. , Marriott D. , Harkness J.
Published: March 2008

We report a case of prosthetic valve infective endocarditis and aortic root abscesses caused by Achromobacter xylosoxidans subsp. xylosoxidans. The patient was an intravenous drug user and had injected amphetamines using ‘duck pond water’ as a diluent. After surgical intervention and 6 weeks of intravenous meropenem therapy, the patient made an uneventful recovery.
Streptococcus sinensis: an emerging agent of infective endocarditis
Authors: Faibis Frédéric , Mihaila Liliana , Perna Sergio , Lefort Jean-François , Demachy Marie-Claude , Le Flèche-Matéos Anne , Bouvet Anne
Published: March 2008

The identification by conventional methods of viridans streptococcal species, which are rarely encountered clinically, requires confirmation by genomic methods. We characterized a strain ofStreptococcus sinensisresponsible for infective endocarditis by sequencing both the 16S rRNA and the manganese-dependent superoxide dismutase genes.
A sustained-release formulation of doxycycline hyclate (Atridox) prevents simultaneous infection of Anaplasma phagocytophilum and Borrelia burgdorferi transmitted by tick bite
Authors: Zeidner Nordin S. , Massung Robert F. , Dolan Marc C. , Dadey Eric , Gabitzsch Elizabeth , Dietrich Gabrielle , Levin Michael L.
Published: March 2008

Current prophylaxis for infected tick bites consists of personal protective measures directed towards ticks. This study compared the efficacy of a single oral dose of doxycycline with that of a single injection of sustained-release doxycycline in a model of Lyme borreliosis and Anaplasma phagocytophilum infection. Dosages of doxycycline were equilibrated based on previously determined peak plasma levels in mice [oral, 2.4 μg (ml plasma)−1; sustained release, 1.9 μg (ml plasma)−1] determined 8 h after inoculation. In challenge experiments where five Borrelia burgdorferi-infected and five A. phagocytophilum-infected nymphs were used per mouse, only 20 and 30 % of mice were protected from B. burgdorferi and A. phagocytophilum infection, respectively, using oral doxycycline. In contrast, 100 % of mice receiving sustained-release doxycycline were protected from A. phagocytophilum infection, as indicated by real-time PCR of blood samples, quantitative PCR and culture isolation of spleen samples, and protected against B. burgdorferi infection as demonstrated by culture of ear, heart and bladder. Although 15–40 copies of A. phagocytophilum could be amplified from the spleens of mice treated with sustained-release doxycycline, no viable A. phagocytophilum from these spleens could be cultured in HL-60 cells. In contrast, 7/10 mice receiving oral doxycycline were PCR- and culture-positive for A. phagocytophilum, with copy numbers ranging from 800 to 10 000 within the spleen, as determined by quantitative PCR. Other correlates with A. phagocytophilum infection included a significant difference in spleen mass (mean of 110 mg for sustained-release treatment versus a mean of 230 mg for oral treatment) and the number of splenic lymphoid nodules (mean of 8 for sustained-release treatment versus mean of 12.5 for oral doxycycline) as determined by histopathology. These studies indicate that a single injection of a sustained-release formulation antibiotic may offer a viable prophylactic treatment option for multiple infectious agents in patients presenting with tick bites.
Burkholderia pseudomallei aerosol infection results in differential inflammatory responses in BALB/c and C57Bl/6 mice
Authors: Tan Gek-Yen Gladys , Liu Yichun , Sivalingam Suppiah Paramalingal , Sim Siew-Hoon , Wang Dongling , Paucod Jean-Charles , Gauthier Yves , Ooi Eng-Eong
Published: March 2008

Melioidosis is caused by the Gram-negative bacterium Burkholderia pseudomallei, whose portals of entry into the body include subcutaneous, ingestion and inhalation routes. Animal models play an important role in furthering our understanding of this disease, which is associated with high morbidity and mortality in susceptible subjects. Previous studies using intranasal inoculation showed a differential susceptibility to inhalational melioidosis in BALB/c and C57Bl/6 mice and attributed the difference to genetic factors and host response. However, a recent study found no difference in susceptibility when the two species of mice were exposed to nebulized bacteria. We sought to address this discrepancy by using a nasal route only, instead of whole-body aerosol exposure system. Employing three different clinical strains of B. pseudomallei and following the progression of disease development in both BALB/c and C57Bl/6 mice, we found that BALB/c mice were at least 10- to 100-fold more susceptible to infection than C57Bl/6 mice. Comparison of bacterial burdens in aerosol-challenged mice, at both the pulmonary and distant sites of infection, suggests that C57Bl/6 mice were more efficient in clearing the bacteria than BALB/c mice. In addition, a comprehensive study of a wide panel of chemokines and cytokines at the protein level demonstrated that hyperproduction of proinflammatory cytokines in aerosol-challenged BALB/c mice did not translate into better protection and survival of these mice, whereas a moderate increase in these proteins in aerosol-challenged C57Bl/6 mice was more beneficial in clearing the infection. This suggests that high levels of proinflammatory cytokines are detrimental and contribute to the immunopathogenesis of the infection.
Distribution of Salmonella pathogenicity island (SPI)-8 and SPI-10 among different serotypes of Salmonella
Authors: Saroj Sunil D. , Shashidhar R. , Karani Manisha , Bandekar Jayant R.
Published: March 2008

Many virulence phenotypes of Salmonella enterica are encoded by genes located on pathogenicity islands. Based on genome analysis, it is predicted that Salmonella pathogenicity island (SPI)-8 is restricted to Salmonella serovars Typhi and Paratyphi A, and SPI-10 to Salmonella serovars Typhi, Paratyphi, Enteritidis, Dublin and Gallinarum. This study was conducted to investigate the distribution of SPI-8 and SPI-10 among Salmonella isolates from sprouts, fish, water and blood. A total of 110 Salmonella isolates and 6 Salmonella serovars from the Microbial Type Culture Collection, Chandigarh, India, were screened. All isolates belonging to Salmonella serovars Washington, Enteritidis and Paratyphi A had both SPI-8 and SPI-10. All Salmonella serovar Typhi isolates from water and blood had both SPI-8 and SPI-10, whereas isolates from fish contained only SPI-8. SPI-8 and SPI-10 were also detected in only 3 out of 42 isolates belonging to Salmonella serovar Typhimurium. Both SPI-8 and SPI-10 were absent in Salmonella serovars Worthington, Dublin, Paratyphi B and Paratyphi C. These results contradict the predictions from Salmonella genome sequences available in GenBank and indicate that SPI-8 and SPI-10 are widely distributed among Salmonella serovars and that virulence factors other than those on SPI-8 and SPI-10 may be responsible for host specificity. This is the first report on the distribution of SPIs in Salmonella isolates from India.
Allelic variation and prevalence of serum opacity factor among the Streptococcus suis population
Authors: Takamatsu Daisuke , Osaki Makoto , Tharavichitkul Prasit , Takai Shinji , Sekizaki Tsutomu
Published: March 2008

Serum opacity factor ofStreptococcus suis(OFS) has recently been identified as a virulence determinant of anS. suisstrain. In this study, we investigated the prevalence and variations of theofsgene among 108S. suisisolates from diseased and healthy pigs, and human patients. PCR screening and sequencing analysis showed that besides theofsgene reported already (designated type 1), there were three allelic variants ofofs(designated types 2 to 4). Type-1 and type-2ofsgenes were expected to encode functional OFS, and SDS extracts of the isolates with type-1ofsand type-2ofsopacified horse serum. Culture supernatants of the isolates with type-2ofsalso showed strong serum opacification activity. In contrast, type-3ofswas interrupted by a point mutation and type-4ofswas disrupted by either insertion of an IS element or genetic rearrangement, and therefore the SDS extracts and culture supernatants of the isolates with type-3ofsand type-4ofsdid not show serum opacification activity. Regardless of their origins, approximately 30 % of the isolates possessed functional OFSs, although type-2ofswas found only in three isolates from healthy pigs. Multilocus sequence typing analysis showed that most of the isolates with type-1ofsbelonged to the sequence type (ST)1 complex, and most of the isolates with type-3ofsand type-4ofsbelonged to the ST27 complex. The isolates with type-2ofswere not assigned to a major ST complex. These results suggest that type-1 OFS contributes to the virulence of a limited number ofS. suisisolates, i.e. those of the ST1 complex type, whereas otherS. suismay not possess this category of virulence factor; the importance of type-2 OFS is obscure.