bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrated active tracking detector for MRI‐guided interventions
Authors: Anders Jens , SanGiorgio Paul , Deligianni Xeni , Santini Francesco , Scheffler Klaus , Boero Giovanni
Published: September 2011

We present a fully integrated detector suitable for active tracking of interventional devices in MR‐guided interventions. The single‐chip microsystem consists of a detection coil, a tuning capacitor, an intermediate frequency downconversion receiver, and a phase‐locked‐loop‐based frequency synthesizer. Thanks to the integrated mixer, the chip output stage delivers an analog frequency‐downconverted NMR signal in the frequency range from 0 to 200 kHz. The microchip, realized in a standard complementary metal oxide semiconductor technology, has a size of 1 × 2 × 0.74 mm3 and operates at a frequency of 63 MHz (i.e., in 1.5 T clinical scanners). Tests in a standard clinical scanner demonstrate the compatibility of the complementary metal oxide semiconductor microchip with clinical MRI systems. Using a solid sample of cis‐polyisoprene having a size of 1 × 1.9 × 0.8 mm3 as internal signal source, the detector achieves a three‐dimensional isotropic spatial resolution of 0.15 mm in a measuring time of 100 ms. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Chronic nerve compression alters schwann cell myelin architecture in a murine model
Authors: Gupta Ranjan , Nassiri Nima , Hazel Antony , Bathen Mary , Mozaffar Tahseen
Published: September 2011

Introduction: Myelinating Schwann cells compartmentalize their outermost layer to form actin‐rich channels known as Cajal bands. Herein we investigate changes in Schwann cell architecture and cytoplasmic morphology in a novel mouse model of carpal tunnel syndrome. Methods: Chronic nerve compression (CNC) injury was created in wild‐type and slow‐Wallerian degeneration (WldS) mice. Over 12 weeks, nerves were electrodiagnostically assessed, and Schwann cell morphology was thoroughly evaluated. Results: A decline in nerve conduction velocity and increase in g‐ratio is observed without early axonal damage. Schwann cells display shortened internodal lengths and severely disrupted Cajal bands. Quite surprisingly, the latter is reconstituted without improvements to nerve conduction velocity. Conclusions: Chronic entrapment injuries like carpal tunnel syndrome are primarily mediated by the Schwann cell response, where decreases in internodal length and myelin thickness disrupt the efficiency of impulse propagation. Restitution of Cajal bands is not sufficient for remyelination after CNC injury. Muscle Nerve, 2012
hp‐FEM for second moments of elliptic PDEs with stochastic data. II: Exponential convergence for stationary singular covariance functions
Authors: Pentenrieder Bastian , Schwab Christoph
Published: September 2011

We prove exponential rates of convergence of a class of hp Galerkin Finite Element approximations of solutions to a model tensor nonhypoelliptic equation in the unit square □ = (0, 1)2 which exhibit singularities on ∂□ and on the diagonal Δ = {(x, y) ∈ □ : x = y}, but are otherwise analytic in □. As we explained in the first part (Pentenrieder and Schwab, Research Report, Seminar for Applied Mathematics, 2010) of this work, such problems arise as deterministic second moment equations of linear, second order elliptic operator equations Au = f with Gaussian random field data f. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2012
Measurement of DL‐α‐difluoromethylornithine concentration using ornithine decarboxylase
Authors: Robins Richard J. , Evans David M.
Published: September 2011

The inhibitor of ornithine decarboxylase, DL‐α‐difluoromethylornithine (DFMO), shows considerable potential in the chemotherapeutic control of lethal protozoal infections. It is also valuable in studies of the metabolism of polyamines. This paper describes a method for the accurate assay of the concentration of this material in aqueous tissue extracts by determining the degree to which a yeast ornithine decarboxylase, expressed on a high‐copy‐number Escherichia coli plasmid, is inhibited. By relating the degree of inhibition to that achieved with standard amounts of DFMO, the concentration present in unknown samples may be determined. The method has been applied to an examination of the conversion by transformed root cultures of Datura stramonium of DL‐α‐difluoromethylarginine to DFMO.
Malondialdehyde titration with thiobarbiturate in plant extracts: Avoidance of pigment interference
Authors: Hagege Daniel , Nouvelot André , Boucaud Jean , Gaspar Thomas
Published: September 2011

Application of the thiobarbiturate acid (TBA) reaction to pigmented plant tissues (sugarbeet green leaves and calli) leads to an overestimation of malondialdehyde (MDA) concentration. A method of MDA estimation for pigmented plant tissues has been developed, using the trichloroacetic acid precipitated protein pellet, with acetone depigmentation, before TBA reaction. Absorbance is measured between 532 and 590 nm.
Protein stability and in vivo concentration of missense mutations in phenylalanine hydroxylase
Authors: Shi Zhen , Sellers Jenn , Moult John
Published: September 2011

A previous computational analysis of missense mutations linked to monogenic disease found a high proportion of missense mutations affect protein stability, rather than other aspects of protein structure and function. The purpose of this study is to relate the presence of such stability damaging missense mutations to the levels of a particular protein present under “in vivo” like conditions, and to test the reliability of the computational methods. Experimental data on a set of missense mutations of the enzyme phenylalanine hydroxylase (PAH) associated with the monogenic disease phenylketonuria (PKU) have been compared with the expected in vivo impact on protein function, obtained using SNPs3D, an in silico analysis package. A high proportion of the PAH mutations are predicted to be destabilizing. The overall agreement between predicted stability impact and experimental evidence for lower protein levels is in accordance with the estimated error rates of the methods. For these mutations, destabilization of protein three‐dimensional structure is the major molecular mechanism leading to PKU, and results in a substantial reduction of in vivo PAH protein concentration. Although of limited scale, the results support the view that destabilization is the most common mechanism by which missense mutations cause monogenic disease. In turn, this conclusion suggests the general therapeutic strategy of developing drugs targeted at restoring wild type stability. Proteins 2012;. © 2011 Wiley Periodicals, Inc.
Computational study of hexanal peroxy radical–water complexes
Authors: Burrell Emily , Clark Jared C. , Snow Mathew , Dumais Heidi , Lee Seong‐cheol , Nielson Brad J. , Osborne Derek , Salamanca‐cardona Lucia , Zemp Logan , Dabell Ryan S. , Hansen Jaron C.
Published: September 2011

The results of an ab initio study on a family of hydroxy peroxy radical–water complexes formed from the oxidation of E‐2‐hexenal, which constitutes an important component of biogenic atmospheric emissions, are reported. Binding energies for the β‐hydroxy‐γ‐peroxy hexanal (β‐ and γ‐positions are relative to the carbonyl) radical–water complex and the γ‐hydroxy‐β‐peroxy hexanal radical–water complex are predicted to be to 3.8 and 3.6 kcal/mol, respectively, computed at the MP2/6‐311++G(2d,2p)//B3LYP/6‐311++G(2d,2p) computational level. Natural bond orbital reveals that conventional hydrogen bonding between the water and the hydroxy and aldehyde functional groups of the radical are primarily responsible for the stability of the complex. It can be shown that the peroxy moiety contributes very little to the stability of the radical–water complexes. Thermochemistry calculations reveal estimated equilibrium constants that are comparable to those recently reported for several hydroxy isoprene radical–water complexes. The results of this report suggest that the hexanal peroxy radical–water complexes are expected to play a significant role in the complex chemistry of the atmosphere. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
PERFORMANCE OF FISH PASSAGE STRUCTURES AT UPSTREAM BARRIERS TO MIGRATION
Authors: Bunt C. M. , Castro‐Santos T. , Haro A.
Published: September 2011

Attraction and passage efficiency were reviewed and compared from 19 monitoring studies that produced data for evaluations of pool‐and‐weir, Denil, vertical‐slot and nature‐like fishways. Data from 26 species of anadromous and potamodromous fishes from six countries were separated by year and taxonomic family into a matrix with 101 records. Attraction performance was highly variable for the following fishway structures: pool‐and‐weir (attraction range = 29–100%, mean = 77%, median = 81%), vertical‐slot (attraction range = 0–100%, mean = 63%, median = 80%), Denil (attraction range = 21–100%, mean = 61%, median = 57%) and nature‐like (attraction range = 0–100%, mean = 48%, median = 50%). Mean passage efficiency was inversely related to mean attraction efficiency by fishway structure type, with the highest passage for nature‐like fishways (range = 0–100%, mean = 70%, median = 86%), followed by Denil (range = 0–97%, mean = 51%, median = 38%), vertical‐slot (range = 0–100%, mean = 45%, median = 43%) and pool‐and‐weir (range = 0–100%, mean = 40%, median = 34%). Principal components analysis and logistic regression modelling indicated that variation in fish attraction was driven by biological characteristics of the fish that were studied, whereas variation in fish passage was related to fishway type, slope and elevation change. This meta‐analysis revealed that the species of fish monitored and structural design of the fishways have strong implications for both attraction and passage performance, and in most cases, existing data are not sufficient to support design recommendations. Many more fishway evaluations are needed over a range of species, fishway types and configurations to characterize, to optimize and to design new fishways. Furthermore, these studies must be performed in a consistent manner to identify the relative contributions of fish attraction and passage to overall fishway performance at each site. Copyright © 2011 John Wiley & Sons, Ltd.
Fassadensysteme zur Sanierung von Wänden aus Sandwichelementen
Authors: Hassinen Paavo , Misiek Thomas , Naujoks Bernd
Published: September 2011

Mit der nachträglichen Verkleidung von Sandwichelementen wird sowohl die Lasteinleitung als auch die Querschnittstragfähigkeit geändert. Basierend auf Versuchsreihen werden zwei Rechenmodelle vorgestellt, die eine Spannungsermittlung für jeden Teilquerschnitt dieses zusammengesetzten Biegeträgers mit Teilverbund ermöglichen und konstruktive Empfehlungen für die Ausführung gegeben.

Cladding systems for the refurbishment of walls made of sandwich panels. Additional cladding fixed in the external face of the sandwich panels change the introduction of the loads, the static behaviour and the resistance of the wall panels. Based on experimental results, two calculation models are presented to evaluate the stresses of the single components which are fixed together with shear flexible joints. Recommendation to build up the structural systems are given.
Tragfähigkeit dünnwandiger Bleche mit elastischer Bettung und Längsversteifungen
Authors: Misiek Thomas , Ummenhofer Thomas , Frank Friederike
Published: September 2011

Sowohl Sicken und Versätze als auch angeschäumte oder geklebte Dämmstoffe können ebene Teilflächen dünnwandiger Bauteile stabilisieren: Sicken und Versätze sind sowohl bei Trapezprofilen als auch bei Sandwichelementen anzutreffen, der stabilisierende Einfluss des Dämmstoffs hingegen nur bei Sandwichelementen. Werden Trapezprofile mit einer kraftschlüssig angeschäumten Dämmstoffen versehen, treten auch hier beide Stabilisierungseffekte auf. Die kombinierte Berücksichtigung beider Effekte in den üblichen Bemessungsprozeduren wird erläutert. Basierend auf den dabei entwickelten Modellen werden Grundzüge für ein neues Bemessungsverfahren für Sandwichelemente mit leicht‐profilierten Deckschichten eingeführt.

Load‐bearing capacity of longitudinally stiffened thin‐walled sheeting on an elastic foundation. Both stiffeners and insulation materials bonded to the sheets can provide stabilization to cross‐section parts of thin‐walled building components. While stiffeners can be found both with trapezoidal sheeting and sandwich panels, the stabilizing effect of the insulation material can only be found with sandwich panels. If trapezoidal sheeting is provided with a force‐fit connected insulation material, also both stabilizing effects apply. The inclusion and combination of both stabilization effects in the usual design and calculation procedures is explained in the paper. Based on the knowledge obtained with the design of trapezoidal sheeting, a new design and calculation concept for sandwich panels with lightly profiled faces is introduced.
Freiformen mit Metallprofilen – Auf die richtige Unterkonstruktion kommt es an
Authors: Schmieder Markus
Published: September 2011

Blob‐Architektur nennt sich die Architektur, die man auch als Nicht‐Standard‐Architektur oder als Freiform‐Architektur bezeichnet. Die Ausführung dieser Gebäudehüllen mit Metallprofilen war mit den bisherigen Technologien des dreidimensional gefertigten MONRO‐Profils nur in der Theorie problemlos möglich. Durch die Entwicklung neuer Unterkonstruktionssysteme und die damit verbundene, wesentlich einfachere Montage dieser anspruchsvollen Gebäudehüllen, lassen sich Blob Gebäude mittlerweile problemlos mit Metallprofilen bekleiden.

Free forms with metal profiles – Depending on a suitable substructure. Blob‐architecture is an architectural style, which is also termed non‐standard‐architecture or free‐form‐architecture. Up to now the construction of claddings with metal profiles made with the current technologies of the three‐dimensional MONRO profiles was hardly practicable. Due to the development of new substructure systems and the associated more simple installation of these ambitious building claddings, it is possible to cover blob buildings with metal profiles easily.
Does childbirth alter the reflex pelvic floor response to coughing?
Authors: Dietz H. P. , Bond V. , Shek K. L.
Published: September 2011

Objective

To determine the prevalence of and to quantify the effect of reflex pelvic floor activation on coughing in nulliparous pregnant women, and to assess peripartal changes and any association with stress urinary incontinence.

Methods

Between April 2008 and March 2010, 131 nulliparous pregnant women were recruited from an antenatal clinic. All participants were interviewed and underwent four‐dimensional translabial ultrasound examination at antepartum (35.8 (mean) weeks' gestation) and postpartum (4.6 (mean) months) visits. Four‐dimensional ultrasound volume datasets of the pelvic floor during coughs were obtained at a minimum frame rate of 16 Hz, using a 10° volume acquisition angle. To quantify a reflex levator contraction we measured the midsagittal hiatal diameter at multiple time points. Levator integrity was determined using tomographic ultrasound imaging.

Results

From 131 women recruited, 47 datasets were technically suboptimal, leaving 84. There was a visible pelvic floor reflex in 82 (98%) cases. At the postpartum visit this was reduced to 63/84, i.e. 75% (P < 0.001). The magnitude of a reflex contraction was markedly reduced postpartum, from 4.8 mm to 2.0 mm (P < 0.001), and this effect was associated with delivery mode (P = 0.042). There was a trend towards an association between lower reflex contraction magnitude and stress incontinence (0.87 ± 3.18 mm vs. 2.36 ± 3.5 mm; P = 0.08) at the postpartum follow‐up visit.

Conclusions

Pelvic floor reflexes are altered by childbirth. This alteration may be associated with vaginal delivery. Reflex magnitude may be associated with postpartum stress urinary incontinence. The clinical significance of this finding is uncertain. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
Symmetry‐adapted perturbation theory of intermolecular forces
Authors: Szalewicz Krzysztof
Published: September 2011

Basic concepts and most recent developments of symmetry‐adapted perturbation theory (SAPT) are described. In particular, the methods that combine SAPT with density‐functional theory are discussed. It is explained how SAPT allows one to predict and understand the structure and properties of clusters and condensed phase. The broadest range of such predictions can be achieved by constructing potential energy surfaces from a set of SAPT interaction energies and using these surfaces in nuclear dynamics calculations. © 2011 John Wiley & Sons, Ltd.

This article is categorized under:

Electronic Structure Theory > Ab Initio Electronic Structure Methods
Zero tolerance, zero evidence: An analysis of school disciplinary practice
Authors: Skiba Russell J. , Knesting Kimberly
Published: September 2011

Because there is little or no evidence of the efficacy of zero tolerance, schools and school districts need to explore preventive alternatives.
Marital Shopping and Epidemic AIDS
Authors: Magruder Jeremy R.
Published: September 2011

HIV risks decline sharply at age 30 for women in South Africa, long before coital frequencies or pregnancies decrease. I evaluate several prominent behavioral models of HIV, and find that these do not suggest sharply decreasing risks with age. I formulate a model of spousal search and find that “marital shopping” can generate epidemic HIV prevalence despite low transmission rates because search behavior interacts with dynamics of HIV infectiousness. The implied age-infection profile closely mimics that in South Africa, and the suggested behavior matches that reported by South Africans. Condom use in new relationships and transmission rate reductions are both found to be effective policies and, when used together, eliminate the potential of spousal search to spread HIV. In contrast, antiretroviral treatment is found to have only a minimal effect on the epidemic.
Groundwater controls on vegetation composition and patterning in mountain meadows
Authors: Lowry Christopher S. , Loheide Steven P. , Moore Courtney E. , Lundquist Jessica D.
Published: September 2011

Mountain meadows are groundwater‐dependent ecosystems that are hot spots of biodiversity and productivity. In the Sierra Nevada mountains of California, these ecosystems rely on shallow groundwater to support their vegetation communities during the dry summer growing season in the region's Mediterranean montane climate. Vegetation composition in this environment is influenced by both (1) oxygen stress that occurs when portions of the root zone are saturated and anaerobic conditions limit root respiration and (2) water stress that occurs when the water table drops and the root zone becomes water limited. A spatially distributed watershed model that explicitly accounts for snowmelt processes was linked to a fine‐resolution groundwater flow model of Tuolumne Meadows in Yosemite National Park, California, to simulate water table dynamics. This linked hydrologic model was calibrated to observations from a well observation network for 2006–2009. A vegetation survey was also conducted at the site in which the three dominant species were identified at more than 200 plots distributed across the meadow. Nonparametric multiplicative regression was performed to create and select the best models for predicting vegetation dominance on the basis of the simulated hydrologic regime. The hydrologic niches of three vegetation types representing wet, moist, and dry meadow vegetation communities were found to be best described using both (1) a sum exceedance value calculated as the integral of water table position above a depth threshold of oxygen stress and (2) a sum exceedance value calculated as the integral of water table position below a depth threshold of water stress. This linked hydrologic and vegetative modeling framework advances our ability to predict the propagation of human‐induced climatic and land use or land cover changes through the hydrologic system to the ecosystem. The hydroecologic functioning of meadows provides an example of the extent to which cascading hydrologic processes at watershed, hillslope, and riparian zones and within channels are reflected in the composition and distribution of riparian vegetation.
Direct microwave transmission on single α-hemolysin pores
Authors: Ramachandran Sujatha , van der Weide Daniel W. , Blick Robert H.
Published: September 2011

We integrated an ultra-broadband microwave circuit for direct sampling of single α-Hemolysin pores in a suspended bilipid membrane. Simultaneous direct current recordings reveal that we can monitor and correlate the radio-frequency transmission signal, with correspondence between open-close states of the direct current and the RF signals. This proves the ability of an RF-readout technique to perform real-time in-vitro recordings of pores. The technique thus holds great promise for research and drug screening applications, since the sampling rate of single channels can be drastically enhanced and the recording bandwidth allows for tracking the passage of single ions.
Bimetallic bonding and mixed oxide formation in the Ga–Pd–CeO2 system
Authors: Skála Tomáš , Tsud Nataliya , Prince Kevin C. , Matolín Vladimír
Published: September 2011

The interaction of gallium and palladium with 2 nm CeO2(111) layers grown on Cu(111) was studied by core level photoelectron spectroscopy and resonant valence band spectroscopy. Palladium alone interacted weakly with ceria layers. Gallium deposited on cerium dioxide formed a mixed Ga2O3–Ce2O3 oxide of 1:1 stoichiometry (cerium gallate CeGaO3), with both metals in the M3+ oxidation state. Increasing Ga coverages led to the formation of lower oxidation states, i.e., Ga1+ in Ga2O oxide and metallic Ga0. Palladium deposited onto this complex system interacted with gallium leading to a breakage of Ga–ceria bonds, a decrease of the oxidation state of gallium, and formation of a Ga–Pd intermetallic alloy in which all components (CeO2, CeGaO3, Ga2O, Ga–Pd, and Pd) are in equilibrium.
Bacterial outer membrane channel for divalent metal ion acquisition
Authors: Hohle Thomas H. , Franck William L. , Stacey Gary , O'Brian Mark R.
Published: September 2011

The prevailing model of bacterial membrane function predicts that the outer membrane is permeable to most small solutes because of pores with limited selectivity based primarily on size. Here, we identified
mnoP
in the Gram-negative bacterium
Bradyrhizobium japonicum
as a gene coregulated with the inner membrane Mn
2+
transporter gene
mntH
. MnoP is an outer membrane protein expressed specifically under manganese limitation. MnoP acts as a channel to facilitate the tranlocation of Mn
2+
, but not Co
2+
or Cu
2+
, into reconstituted proteoliposomes. An
mnoP
mutant is defective in high-affinity Mn
2+
transport into cells and has a severe growth phenotype under manganese limitation. We suggest that the outer membrane is a barrier to divalent metal ions that requires a selective channel to meet the nutritional needs of the cell.
Neutrophil transmigration triggers repair of the lung epithelium via β-catenin signaling
Authors: Zemans Rachel L. , Briones Natalie , Campbell Megan , McClendon Jazalle , Young Scott K. , Suzuki Tomoko , Yang Ivana V. , De Langhe Stijn , Reynolds Susan D. , Mason Robert J. , Kahn Michael , Henson Peter M. , Colgan Sean P. , Downey Gregory P.
Published: September 2011

Injury to the epithelium is integral to the pathogenesis of many inflammatory lung diseases, and epithelial repair is a critical determinant of clinical outcome. However, the signaling pathways regulating such repair are incompletely understood. We used in vitro and in vivo models to define these pathways. Human neutrophils were induced to transmigrate across monolayers of human lung epithelial cells in the physiological basolateral-to-apical direction. This allowed study of the neutrophil contribution not only to the initial epithelial injury, but also to its repair, as manifested by restoration of transepithelial resistance and reepithelialization of the denuded epithelium. Microarray analysis of epithelial gene expression revealed that neutrophil transmigration activated β-catenin signaling, and this was verified by real-time PCR, nuclear translocation of β-catenin, and TOPFlash reporter activity. Leukocyte elastase, likely via cleavage of E-cadherin, was required for activation of β-catenin signaling in response to neutrophil transmigration. Knockdown of β-catenin using shRNA delayed epithelial repair. In mice treated with intratracheal LPS or keratinocyte chemokine, neutrophil emigration resulted in activation of β-catenin signaling in alveolar type II epithelial cells, as demonstrated by cyclin D1 expression and/or reporter activity in TOPGAL mice. Attenuation of β-catenin signaling by IQ-1 inhibited alveolar type II epithelial cell proliferation in response to neutrophil migration induced by intratracheal keratinocyte chemokine. We conclude that β-catenin signaling is activated in lung epithelial cells during neutrophil transmigration, likely via elastase-mediated cleavage of E-cadherin, and regulates epithelial repair. This pathway represents a potential therapeutic target to accelerate physiological recovery in inflammatory lung diseases.
Mechanism and cellular function of Bud6 as an actin nucleation–promoting factor
Authors: Graziano Brian R. , DuPage Amy Grace , Michelot Alphee , Breitsprecher Dennis , Moseley James B. , Sagot Isabelle , Blanchoin Laurent , Goode Bruce L.
Published: September 2011

Formins are a conserved family of actin assembly–promoting factors with diverse biological roles, but how their activities are regulated in vivo is not well understood. In Saccharomyces cerevisiae, the formins Bni1 and Bnr1 are required for the assembly of actin cables and polarized cell growth. Proper cable assembly further requires Bud6. Previously it was shown that Bud6 enhances Bni1-mediated actin assembly in vitro, but the biochemical mechanism and in vivo role of this activity were left unclear. Here we demonstrate that Bud6 specifically stimulates the nucleation rather than the elongation phase of Bni1-mediated actin assembly, defining Bud6 as a nucleation-promoting factor (NPF) and distinguishing its effects from those of profilin. We generated alleles of Bud6 that uncouple its interactions with Bni1 and G-actin and found that both interactions are critical for NPF activity. Our data indicate that Bud6 promotes filament nucleation by recruiting actin monomers to Bni1. Genetic analysis of the same alleles showed that Bud6 regulation of formin activity is critical for normal levels of actin cable assembly in vivo. Our results raise important mechanistic parallels between Bud6 and WASP, as well as between Bud6 and other NPFs that interact with formins such as Spire.
Kinematic measures for assessing gait stability in elderly individuals: a systematic review
Authors: Hamacher D. , Singh N.B. , Van Dieën J.H. , Heller M.O. , Taylor W.R.
Published: September 2011

Falls not only present a considerable health threat, but the resulting treatment and loss of working days also place a heavy economic burden on society. Gait instability is a major fall risk factor, particularly in geriatric patients, and walking is one of the most frequent dynamic activities of daily living. To allow preventive strategies to become effective, it is therefore imperative to identify individuals with an unstable gait. Assessment of dynamic stability and gait variability via biomechanical measures of foot kinematics provides a viable option for quantitative evaluation of gait stability, but the ability of these methods to predict falls has generally not been assessed. Although various methods for assessing gait stability exist, their sensitivity and applicability in a clinical setting, as well as their cost-effectiveness, need verification. The objective of this systematic review was therefore to evaluate the sensitivity of biomechanical measures that quantify gait stability among elderly individuals and to evaluate the cost of measurement instrumentation required for application in a clinical setting. To assess gait stability, a comparative effect size (Cohen's
d
) analysis of variability and dynamic stability of foot trajectories during level walking was performed on 29 of an initial yield of 9889 articles from four electronic databases. The results of this survey demonstrate that linear variability of temporal measures of swing and stance was most capable of distinguishing between fallers and non-fallers, whereas step width and stride velocity prove more capable of discriminating between old versus young (OY) adults. In addition, while orbital stability measures (Floquet multipliers) applied to gait have been shown to distinguish between both elderly fallers and non-fallers as well as between young and old adults, local stability measures (
λ
s) have been able to distinguish between young and old adults. Both linear and nonlinear measures of foot time series during gait seem to hold predictive ability in distinguishing healthy from fall-prone elderly adults. In conclusion, biomechanical measurements offer promise for identifying individuals at risk of falling and can be obtained with relatively low-cost tools. Incorporation of the most promising measures in combined retrospective and prospective studies for understanding fall risk and designing preventive strategies is warranted.
Oligogalacturonide-Auxin Antagonism Does Not Require Posttranscriptional Gene Silencing or Stabilization of Auxin Response Repressors in Arabidopsis
Authors: Savatin Daniel V. , Ferrari Simone , Sicilia Francesca , De Lorenzo Giulia
Published: September 2011

α-1-4-Linked oligogalacturonides (OGs) derived from plant cell walls are a class of damage-associated molecular patterns and well-known elicitors of the plant immune response. Early transcript changes induced by OGs largely overlap those induced by flg22, a peptide derived from bacterial flagellin, a well-characterized microbe-associated molecular pattern, although responses diverge over time. OGs also regulate growth and development of plant cells and organs, due to an auxin-antagonistic activity. The molecular basis of this antagonism is still unknown. Here we show that, in Arabidopsis (Arabidopsis thaliana), OGs inhibit adventitious root formation induced by auxin in leaf explants as well as the expression of several auxin-responsive genes. Genetic, biochemical, and pharmacological experiments indicate that inhibition of auxin responses by OGs does not require ethylene, jasmonic acid, and salicylic acid signaling and is independent of RESPIRATORY BURST OXIDASE HOMOLOGUE D-mediated reactive oxygen species production. Free indole-3-acetic acid levels are not noticeably altered by OGs. Notably, OG- as well as flg22-auxin antagonism does not involve any of the following mechanisms: (1) stabilization of auxin-response repressors; (2) decreased levels of auxin receptor transcripts through the action of microRNAs. Our results suggest that OGs and flg22 antagonize auxin responses independently of Aux/Indole-3-Acetic Acid repressor stabilization and of posttranscriptional gene silencing.
Estimation of geological dip and curvature from time‐migrated zero‐offset reflections in heterogeneous anisotropic media
Authors: Tygel Martin , Ursin Bjørn , Iversen Einar , de Hoop Maarten V.
Published: September 2011

Starting from a given time‐migrated zero‐offset data volume and time‐migration velocity, recent literature has shown that it is possible to simultaneously trace image rays in depth and reconstruct the depth‐velocity model along them. This, in turn, allows image‐ray migration, namely to map time‐migrated reflections into depth by tracing the image ray until half of the reflection time is consumed. As known since the 1980s, image‐ray migration can be made more complete if, besides reflection time, also estimates of its first and second derivatives with respect to the time‐migration datum coordinates are available. Such information provides, in addition to the location and dip of the reflectors in depth, also an estimation of their curvature. The expressions explicitly relate geological dip and curvature to first and second derivatives of reflection time with respect to time‐migration datum coordinates. Such quantitative relationships can provide useful constraints for improved construction of reflectors at depth in the presence of uncertainty. Furthermore, the results of image‐ray migration can be used to verify and improve time‐migration algorithms and can therefore be considered complementary to those of normal‐ray migration. So far, image‐ray migration algorithms have been restricted to layered models with isotropic smooth velocities within the layers. Using the methodology of surface‐to‐surface paraxial matrices, we obtain a natural extension to smooth or layered anisotropic media.
New developments of the magnetic tilt‐depth method to improve structural mapping of sedimentary basins
Authors: Fairhead J. Derek , Salem Ahmed , Cascone Lorenzo , Hammill M. , Masterton Sheona , Samson Esuene
Published: September 2011

This paper interprets aeromagnetic data for a deep basin section of the Karroo rift in south‐east Tanzania. We use a novel integrated approach involving the application of advanced derivatives to define structure and the tilt‐depth method to determine and map the depth to basement. In the latter case we use the result of both reduced to pole and reduced to equator data to help constrain the shape and depth of the basin. We show that for a reduced to pole aeromagnetic data set, the generalized form of the local phase, called the tilt derivative, is an effective means of providing an initial (first pass) mapping of a sedimentary basin in terms of its fault structure, dip direction of faults and depth to basement. Since the amplitude of the tilt derivative does not contain information on the strength of the geomagnetic field nor magnetization (other than inclination) of the causative body, the susceptibility contrast across faults/contacts is derived from the analytic signal derivative. We also investigate how effective the tilt derivative and tilt‐depth method are for structural and depth to basement mapping in regions close to the magnetic equator, where the reduction to pole transform is often unstable; this is done using the same Tanzania data set transformed to the pole and the equator. We find that the tilt derivative applied to the reduction to equator data cannot be used to map the structure because of the effects of magnetic anisotropy, which results in the magnetic response of structures varying with strike azimuth. To overcome this anisotropy problem the analytic signal and/or local wavenumber derivatives, which are for all practical purposes independent of inclination, provide the best means of defining the major structural trends. We also find that the tilt‐depth method provides coherent depth to basement estimates for both reduced to pole and reduced to equator data. For the deep basin sections of the Karroo rift, there is a sparsity of tilt‐depth results from both the reduced to pole and reduced to equator data sets. However, each set of results has a different spatial coverage, so when combined they provide a better spatial sampling of the long wavelength magnetic character of the basin and thus improve the constraints on the minimum curvature gridding method to map the shape and depth of the basin.
ABGD, Automatic Barcode Gap Discovery for primary species delimitation
Authors: PUILLANDRE N. , LAMBERT A. , BROUILLET S. , ACHAZ G.
Published: September 2011

Within uncharacterized groups, DNA barcodes, short DNA sequences that are present in a wide range of species, can be used to assign organisms into species. We propose an automatic procedure that sorts the sequences into hypothetical species based on the barcode gap, which can be observed whenever the divergence among organisms belonging to the same species is smaller than divergence among organisms from different species. We use a range of prior intraspecific divergence to infer from the data a model‐based one‐sided confidence limit for intraspecific divergence. The method, called Automatic Barcode Gap Discovery (ABGD), then detects the barcode gap as the first significant gap beyond this limit and uses it to partition the data. Inference of the limit and gap detection are then recursively applied to previously obtained groups to get finer partitions until there is no further partitioning. Using six published data sets of metazoans, we show that ABGD is computationally efficient and performs well for standard prior maximum intraspecific divergences (a few per cent of divergence for the five data sets), except for one data set where less than three sequences per species were sampled. We further explore the theoretical limitations of ABGD through simulation of explicit speciation and population genetics scenarios. Our results emphasize in particular the sensitivity of the method to the presence of recent speciation events, via (unrealistically) high rates of speciation or large numbers of species. In conclusion, ABGD is fast, simple method to split a sequence alignment data set into candidate species that should be complemented with other evidence in an integrative taxonomic approach.
Cretaceous black shale: a window into microbial life adaptation
Authors: Pacton Muriel , Schmid Thomas , Gorin Georges , Massault Marc , Stadler Johannes
Published: September 2011

Terra Nova, 23, 362–368, 2011

As bacteria are usually incompletely preserved in the geological record, their recognition can only be based on their degradation‐resistant cell walls. However, the latter provide no indication about conditions occurring before the death of the bacteria. In this article, we attempt to demonstrate the syngenecity of bacteria found in the Albian oceanic anoxic event (OAE1b) from the Urbino level and highlight their physiology from their possible intracellular components. Dark storage inclusions have been identified as inorganic polyphosphate, in addition to carotenoids which have been encountered in the cell. Before death, stress and deprivation resulted in drastic changes in physiology generating properties such as regulatory functions of polyphosphates and the ability of carotenoids to rigidify membranes. Therefore, this starvation strategy induced a more resistant state possibly enhancing the preservation of these bacteria. These results demonstrate the potential for exploring indications of past microbial life in other black shales.
The pyruvate, orthophosphate dikinase regulatory proteins of Arabidopsis are both bifunctional and interact with the catalytic and nucleotide‐binding domains of pyruvate, orthophosphate dikinase
Authors: Astley Holly M. , Parsley Kate , Aubry Sylvain , Chastain Chris J. , Burnell Jim N. , Webb Michael E. , Hibberd Julian M.
Published: September 2011

Pyruvate orthophosphate dikinase (PPDK) is a key enzyme in C4 photosynthesis and is also found in C3 plants. It is post‐translationally modified by the PPDK regulatory protein (RP) that possesses both kinase and phosphotransferase activities. Phosphorylation and dephosphorylation of PPDK lead to inactivation and activation respectively. Arabidopsis thaliana contains two genes that encode chloroplastic (RP1) and cytosolic (RP2) isoforms of RP, and although RP1 has both kinase and phosphotransferase activities, to date RP2 has only been shown to act as a kinase. Here we demonstrate that RP2 is able to catalyse the dephosphorylation of PPDK, although at a slower rate than RP1 under the conditions of our assay. From yeast two‐hybrid analysis we propose that RP1 binds to the central catalytic domain of PPDK, and that additional regions towards the carboxy and amino termini are required for a stable interaction between RP2 and PPDK. For 21 highly conserved amino acids in RP1, mutation of 15 of these reduced kinase and phosphotransferase activity, while mutation of six residues had no impact on either activity. We found no mutant in which only one activity was abolished. However, in some chimaeric fusions that comprised the amino and carboxy termini of RP1 and RP2 respectively, the kinase reaction was severely compromised but phosphotransferase activity remained unaffected. These findings are consistent with the findings that both RP1 and RP2 modulate reversibly the activity of PPDK, and possess one bifunctional active site or two separate sites in close proximity.
A rice calcium‐dependent protein kinase OsCPK12 oppositely modulates salt‐stress tolerance and blast disease resistance
Authors: Asano Takayuki , Hayashi Nagao , Kobayashi Michie , Aoki Naohiro , Miyao Akio , Mitsuhara Ichiro , Ichikawa Hiroaki , Komatsu Setsuko , Hirochika Hirohiko , Kikuchi Shoshi , Ohsugi Ryu
Published: September 2011

Calcium‐dependent protein kinases (CDPKs) regulate the downstream components in calcium signaling pathways. We investigated the effects of overexpression and disruption of an Oryza sativa (rice) CDPK (OsCPK12) on the plant’s response to abiotic and biotic stresses. OsCPK12‐overexpressing (OsCPK12‐OX) plants exhibited increased tolerance to salt stress. The accumulation of hydrogen peroxide (H2O2) in the leaves was less in OsCPK12‐OX plants than in wild‐type (WT) plants. Genes encoding reactive oxygen species (ROS) scavenging enzymes (OsAPx2 and OsAPx8) were more highly expressed in OsCPK12‐OX plants than in WT plants, whereas the expression of the NADPH oxidase gene, OsrbohI, was decreased in OsCPK12‐OX plants compared with WT plants. Conversely, a retrotransposon (Tos17) insertion mutant, oscpk12, and plants transformed with an OsCPK12 RNA interference (RNAi) construct were more sensitive to high salinity than were WT plants. The level of H2O2 accumulation was greater in oscpk12 and OsCPK12 RNAi plants than in the WT. These results suggest that OsCPK12 promotes tolerance to salt stress by reducing the accumulation of ROS. We also observed that OsCPK12‐OX seedlings had increased sensitivity to abscisic acid (ABA) and increased susceptibility to blast fungus, probably resulting from the repression of ROS production and/or the involvement of OsCPK12 in the ABA signaling pathway. Collectively, our results suggest that OsCPK12 functions in multiple signaling pathways, positively regulating salt tolerance and negatively modulating blast resistance.
Dynamic evolution of herbivore‐induced sesquiterpene biosynthesis in sorghum and related grass crops
Authors: Zhuang Xiaofeng , Köllner Tobias G. , Zhao Nan , Li Guanglin , Jiang Yifan , Zhu Liucun , Ma Jianxin , Degenhardt Jörg , Chen Feng
Published: September 2011

Sorghum (Sorghum bicolor) plants damaged by insects emit a blend of volatiles, predominantly sesquiterpenes, that are implicated in attracting natural enemies of the attacking insects. To characterize sesquiterpene biosynthesis in sorghum, seven terpene synthase (TPS) genes, SbTPS1 through SbTPS7, were identified based on their evolutionary relatedness to known sesquiterpene synthase genes from maize and rice. While SbTPS6 and SbTPS7 encode truncated proteins, all other TPS genes were determined to encode functional sesquiterpene synthases. Both SbTPS1 and SbTPS2 produced the major products zingiberene, β‐bisabolene and β‐sesquiphellandrene, but with opposite ratios of zingiberene to β‐sesquiphellandrene. SbTPS3 produced (E)‐α‐bergamotene and (E)‐β‐farnesene. SbTPS4 formed (E)‐β‐caryophyllene as the major product. SbTPS5 produced mostly (E)‐α‐bergamotene and (Z)‐γ‐bisabolene. Based on the genome sequences of sorghum, maize and rice and the sesquiterpene synthase genes they contain, collinearity analysis identified the orthologs of sorghum sesquiterpene synthase genes, except for SbTPS4, in maize and rice. Phylogenetic analysis implied that SbTPS1, SbTPS2 and SbTPS3, which exist as tandem repeats, evolved as a consequence of local gene duplication in a lineage‐specific manner. Structural modeling and site‐directed mutagenesis experiments revealed that three amino acids in the active site play critical roles in defining product specificity of SbTPS1, SbTPS2, SbTPS3 and their orthologs in maize and rice. The naturally occurring functional variations of sesquiterpene synthases within and between species suggest that multiple mechanisms, including lineage‐specific gene duplication, subfunctionalization, neofunctionalization and pseudogenization of duplicated genes, have all played a role in the dynamic evolution of insect‐induced sesquiterpene biosynthesis in grasses.
A tomato LysM receptor‐like kinase promotes immunity and its kinase activity is inhibited by AvrPtoB
Authors: Zeng Lirong , Velásquez André C. , Munkvold Kathy R. , Zhang Jingwei , Martin Gregory B.
Published: September 2011

Resistance in tomato (Solanum lycopersicum) to infection by Pseudomonas syringae involves both detection of pathogen‐associated molecular patterns (PAMPs) and recognition by the host Pto kinase of pathogen effector AvrPtoB which is translocated into the host cell and interferes with PAMP‐triggered immunity (PTI). The N‐terminal portion of AvrPtoB is sufficient for its virulence activity and for recognition by Pto. An amino acid substitution in AvrPtoB, F173A, abolishes these activities. To investigate the mechanisms of AvrPtoB virulence, we screened for tomato proteins that interact with AvrPtoB and identified Bti9, a LysM receptor‐like kinase. Bti9 has the highest amino acid similarity to Arabidopsis CERK1 among the tomato LysM receptor‐like kinases (RLKs) and belongs to a clade containing three other tomato proteins, SlLyk11, SlLyk12, and SlLyk13, all of which interact with AvrPtoB. The F173A substitution disrupts the interaction of AvrPtoB with Bti9 and SlLyk13, suggesting that these LysM‐RLKs are its virulence targets. Two independent tomato lines with RNAi‐mediated reduced expression of Bti9 and SlLyk13 were more susceptible to P. syringae. Bti9 kinase activity was inhibited in vitro by the N‐terminal domain of AvrPtoB in an F173‐dependent manner. These results indicate Bti9 and/or SlLyk13 play a role in plant immunity and the N‐terminal domain of AvrPtoB may have evolved to interfere with their kinase activity. Finally, we found that Bti9 and Pto interact with AvrPtoB in a structurally similar although not identical fashion, suggesting that Pto may have evolved as a molecular mimic of LysM‐RLK kinase domains.
Humoral immunomodulatory effect of influenza vaccine in potential blood donors: implications for transfusion safety
Authors: Delaney M. , Warner P. , Nelson K. , Gleckler C. , Price T. , Madeleine M.
Published: September 2011

Background: Generalised immune stimulation may follow vaccination causing increased antibody titres of nonvaccine‐related antibodies or bystander antibodies, including those to human leukocyte antigens (HLA) and ABO blood group antigens. HLA antibodies may lead to transfusion‐related acute lung injury. High‐titre ABO antibodies may cause acute haemolytic transfusion reactions after plasma‐incompatible platelet transfusion. It is unknown if these antibodies can be stimulated by vaccination in otherwise normal subjects.

Methods: Blood samples of healthy volunteers who received the 2009 influenza vaccine were analysed for HLA and ABO antibodies before and 14 days after vaccination (n = 86). Age, gender and history of exposure to foreign tissue, through pregnancy, blood transfusion or tissue transplant were collected. Results were analysed with descriptive statistics, paired t‐test and χ2 test.

Results: There was no increase in HLA or ABO antibody levels after vaccination (P = not significant). Forty per cent of subjects (n = 35) had previously formed HLA antibody and 16% (7 males and 7 females) had HLA sensitisation but did not report foreign tissue exposure. The average panel reactive antibody of the HLA sensitised but nonexposed subjects was lower in males than females (3·4 and 28·6%, respectively, P = 0·015, t‐test), suggesting that some females may have had unrecognised pregnancy.

Conclusions: HLA or ABO antibodies did not appear to be stimulated by the 2009 influenza vaccine. Female blood donors with putatively unrecognised pregnancies may have higher risk for HLA sensitisation than previously thought. Further study using different vaccine formulations may lead to better understanding of the risks of bystander antibodies in the blood donor population.