bluuebunny/crossref_metadata_2025 huggingface dataset:
Pulse-train control of photofragmentation at constant field energy
Authors: Tiwari Ashwani K. , Henriksen Niels E.
Published: November 2014

We consider a phaselocked two-pulse sequence applied to photofragmentation in the weak-field limit. The two pulses are not overlapping in time, i.e., the energy of the pulse-train is constant for all time delays. It is shown that the relative yield of excited \documentclass[12pt]{minimal}\begin{document}$\rm Br^{\ast }$\end{document} Br * in the nonadiabatic process: I + Br* ← IBr → I + Br, changes as a function of time delay when the two excited wave packets interfere. The underlying mechanisms are analyzed and the change in the branching ratio as a function of time delay is only a reflection of a changing frequency distribution of the pulse train; the branching ratio does not depend on the detailed pulse shape.
Effect of viscosity, electrical conductivity, and surface tension on direct-current-pulsed drop-on-demand electrohydrodynamic printing frequency
Authors: An Seongpil , Lee Min Wook , Kim Na Young , Lee Changmin , Al-Deyab Salem S. , James Scott C. , Yoon Sam S.
Published: November 2014

Experiments were conducted to measure the performance of direct-current-pulsed electrohydrodynamic drop formation as a function of liquid viscosity, electrical conductivity, and surface tension. While hydrodynamic and charge relaxation times and Taylor cone formation frequencies suggest theoretical drop-generation frequencies well in excess of 100 Hz, we show that it is impossible to produce more than 50 drops per second with performance decreasing as viscosity increased or electrical conductivity decreased (and not a significant function of surface tension). Instead of relying on relaxation-time calculations to predict the maximum, reliable drop-production frequency, a dimensionless coefficient that is a function of viscosity and electrical conductivity is proposed to estimate the fulcrum frequency.
Simulating the spectral response of quantum dot-in-well infrared photodetectors from eight band k.p method
Authors: Anjan Kumar V. , Pendyala Naresh Babu , Banerjee Arup
Published: November 2014

Conduction band energy levels in quantum-dot-in-a-well structures are computed by eight band k.p method (Burt-Foreman Hamiltonian) using finite element software. Optical absorption spectrum due to intersubband transitions is simulated using Fermi golden rule. The use of contact pair boundary condition in strain calculation and criteria for choosing band mixing parameter (Ep) to avoid the spurious solutions are examined in this paper. The simulated intersubband optical absorption spectrum of different structures reported in the literature is in close agreement with the experimentally measured photoconductive absorption region and shows that the method can be used as an effective modeling for quick design of the heterostructures based infrared photodetectors for various wavelengths.
Damping of metallized bilayer nanomechanical resonators at room temperature
Authors: Seitner Maximilian J. , Gajo Katrin , Weig Eva M.
Published: November 2014

We investigate the influence of gold thin-films subsequently deposited on a set of initially bare, doubly clamped, high-stress silicon nitride string resonators at room temperature. Analytical expressions for resonance frequency, quality factor and damping for both in- and out-of-plane flexural modes of the bilayer system are presented, which allows for the determination of effective elastic parameters of the composite structure from our experimental data. We find the inverse quality factor to scale linearly with the gold film thickness, indicating that the overall damping is governed by losses in the metal. Correspondingly, the mechanical linewidth increases by more than one order of magnitude compared to the bare silicon nitride string resonator. Furthermore, we extract mechanical quality factors of the gold film for both flexural modes and show that they can be enhanced by complete deposition of the metal in a single step, suggesting that surface and interface losses play a vital role in metal thin-films.
Single-walled carbon nanotubes based chemiresistive genosensor for label-free detection of human rheumatic heart disease
Authors: Singh Swati , Kumar Ashok , Khare Shashi , Mulchandani Ashok , Rajesh
Published: November 2014

A specific and ultrasensitive, label free single-walled carbon nanotubes (SWNTs) based chemiresistive genosensor was fabricated for the early detection of Streptococcus pyogenes infection in human causing rheumatic heart disease. The mga gene of S. pyogenes specific 24 mer ssDNA probe was covalently immobilized on SWNT through a molecular bilinker, 1-pyrenemethylamine, using carbodiimide coupling reaction. The sensor was characterized by the current-voltage (I-V) characteristic curve and scanning electron microscopy. The sensing performance of the sensor was studied with respect to changes in conductance in SWNT channel based on hybridization of the target S. pyogenes single stranded genomic DNA (ssG-DNA) to its complementary 24 mer ssDNA probe. The sensor shows negligible response to non-complementary Staphylococcus aureus ssG-DNA, confirming the specificity of the sensor only with S. pyogenes. The genosensor exhibited a linear response to S. pyogenes G-DNA from 1 to1000 ng ml−1 with a limit of detection of 0.16 ng ml−1.
Non-equilibrium Green's functions method: Non-trivial and disordered leads
Authors: He Yu , Wang Yu , Klimeck Gerhard , Kubis Tillmann
Published: November 2014

The non-equilibrium Green's function algorithm requires contact self-energies to model charge injection and extraction. All existing approaches assume infinitely periodic leads attached to a possibly quite complex device. This contradicts today's realistic devices in which contacts are spatially inhomogeneous, chemically disordered, and impacting the overall device characteristics. This work extends the complex absorbing potentials method for arbitrary, ideal, or non-ideal leads in atomistic tight binding representation. The algorithm is demonstrated on a Si nanowire with periodic leads, a graphene nanoribbon with trumpet shape leads, and devices with leads of randomly alloyed Si0.5Ge0.5. It is found that alloy randomness in the leads can reduce the predicted ON-state current of Si0.5Ge0.5 transistors by 45% compared to conventional lead methods.
Mg2Si anode for Li-ion batteries: Linking structural change to fast capacity fading
Authors: Ma Ruijun , Liu Yongfeng , Yang Yaxiong , Gao Mingxia , Pan Hongge
Published: November 2014

This work reports on the underlying mechanism of the fast capacity fading of Mg2Si. The linking of the structural change and degradation behavior that occurs during cycling shows that the dissociation and irreversible lithiation of Mg is the critical factor for the capacity fading of a Mg2Si anode. This mechanism was further proven by designing a ternary Li2MgSi that exhibited significantly improved cycling stability because of the elimination of the intermediate Mg upon charging/discharging. This finding is useful as a general guideline and inspiration for improving the cycling stability of Mg2Si anodes and designing anode materials with long-term cyclability.
In-situ scanning electron microscopy study of fracture events during back-end-of-line microbeam bending tests
Authors: Vanstreels K. , De Wolf I. , Zahedmanesh H. , Bender H. , Gonzalez M. , Lefebvre J. , Bhowmick S.
Published: November 2014

This paper demonstrates the direct observation of crack initiation, crack propagation, and interfacial delamination events during in-situ microbeam bending tests of FIB milled BEOL structures. The elastic modulus and the critical force of fracture of the BEOL beam samples were compared for beams of different length and width.
Defect-free ZnO nanorods for low temperature hydrogen sensor applications
Authors: Ranwa Sapana , Kulriya Pawan K. , Sahu Vikas Kumar , Kukreja L. M. , Kumar Mahesh
Published: November 2014

Uniformly distributed and defect-free vertically aligned ZnO nanorods (NRs) with high aspect ratio are deposited on Si by sputtering technique. X-ray diffraction along with transmission electron microscopy studies confirmed the single crystalline wurtzite structure of ZnO. Absence of wide band emission in photoluminescence spectra showed defect-free growth of ZnO NRs which was further conformed by diamagnetic behavior of the NRs. H2 sensing mechanism based on the change in physical dimension of channel is proposed to explain the fast response (∼21.6 s) and recovery times (∼27 s) of ZnO NRs/Si/ZnO NRs sensors. Proposed H2 sensor operates at low temperature (∼70 °C) unlike the existing high temperature (>150 °C) sensors.
Calorimetric and magnetic study for Ni50Mn36In14 and relative cooling power in paramagnetic inverse magnetocaloric systems
Authors: Chen Jing-Han , Bruno Nickolaus M. , Karaman Ibrahim , Huang Yujin , Li Jianguo , Ross Joseph H.
Published: November 2014

The non-stoichiometric Heusler alloy Ni50Mn36In14 undergoes a martensitic phase transformation in the vicinity of 345 K, with the high temperature austenite phase exhibiting paramagnetic rather than ferromagnetic behavior, as shown in similar alloys with lower-temperature transformations. Suitably prepared samples are shown to exhibit a sharp transformation, a relatively small thermal hysteresis, and a large field-induced entropy change. We analyzed the magnetocaloric behavior both through magnetization and direct field-dependent calorimetry measurements. For measurements passing through the first-order transformation, an improved method for heat-pulse relaxation calorimetry was designed. The results provide a firm basis for the analytic evaluation of field-induced entropy changes in related materials. An analysis of the relative cooling power (RCP), based on the integrated field-induced entropy change and magnetizing behavior of the Mn spin system with ferromagnetic correlations, shows that a significant RCP may be obtained in these materials by tuning the magnetic and structural transformation temperatures through minor compositional changes or local order changes.
Accurate extraction of mobility in carbon nanotube network transistors using C-V and I-V measurements
Authors: Yoon Jinsu , Lee Dongil , Kim Chaewon , Lee Jieun , Choi Bongsik , Kim Dong Myong , Kim Dae Hwan , Lee Mijung , Choi Yang-Kyu , Choi Sung-Jin
Published: November 2014

The mobility of single-walled carbon nanotube (SWNT) network thin-film transistors (TFTs) is an essential parameter. Previous extraction methods for mobility encountered problems in extracting accurate intrinsic mobility due to the uncertainty of the SWNT density in the network channel and the existence of contact resistance at the source/drain electrodes. As a result, efficient and accurate extraction of the mobility in SWNT TFTs is challenging using previous methods. We propose a direct method of extracting accurate intrinsic mobility in SWNT TFTs by employing capacitance-voltage and current-voltage measurements. Consequently, we simply obtain accurate intrinsic mobility within the ink-jet printed SWNT TFTs without any complicated calculations.
Photonic E-field sensor
Authors: Savchenkov A. A. , Liang W. , Ilchenko V. S. , Dale E. , Savchenkova E. A. , Matsko A. B. , Seidel D. , Maleki L.
Published: November 2014

We report on both theoretical and experimental studies of a photonic implementation of the electric (E-) field sensor using a probe made with all-dielectric RF-transparent elements. The geometrical dimensions of the electric field probe can be smaller than the wavelength of the measured electromagnetic field in the material. Our theoretical calculations show that the sensor allows detecting electric fields in a broad frequency range (100 Hz-20 GHz) with sensitivity better than 1 μV/[Hz1/2 m]. We demonstrate the sensor operating at X-band and validate the theoretical predictions.
How different pruning severities alter shoot structure: a modelling approach in young ‘Nonpareil’ almond trees
Authors: Negrón Claudia , Contador Loreto , Lampinen Bruce D. , Metcalf Samuel G. , Guédon Yann , Costes Evelyne , DeJong Theodore M.
Published: November 2014

Axillary meristem fate patterns along shoots, also referred to as shoot structure, appear to be fairly consistent among trees within a genotype growing under similar conditions. Less is known about shoot structural plasticity following external manipulations, such as pruning. The aim of this study on almond (Prunus dulcis (Mill.)) shoots was to investigate how pruning severity affects the structure of 1-year-old shoots that grew after pruning (regrowth shoots), the 2-year-old portion of shoots that remained from the previous year’s growth after pruning (pruned shoots), and whether regrowth shoots reiterate the structure of the original 1-year-old shoots before pruning. Three pruning severities were imposed and the structures along the different shoots were assessed by building hidden semi-Markov models of axillary meristem fates. The structures of regrowth and pruned shoots depended on pruning severity, but maintained some of the original shoot characteristics. Regrowth shoots developed more complex structures with severe pruning, but had simpler structures than original shoots indicating progressive simplification with tree age. Pruned shoot structures were affected by the severity of pruning, by the structure when the shoots were 1 year old, and probably by local competition among buds. Changes in structure due to pruning can be modelled and be predictable.
Water relations of an invasive halophyte (Spartina patens): osmoregulation and ionic effects on xylem hydraulics
Authors: Casolo Valentino , Tomasella Martina , De Col Valentina , Braidot Enrico , Savi Tadeja , Nardini Andrea
Published: November 2014

Spartina patens (Ait.) Muhl. is a grass native to the Atlantic coastal area of North America currently invading salt marsh ecosystems in several regions of Europe. We investigated leaf water relations and hydraulics, gas exchange, nitrogen and starch content in two populations of S. patens growing under contrasting salinity levels in a salt marsh and in a dune system in order to assess its functional plasticity as a factor contributing to its invasive potential. The analysis of leaf water relations revealed a suite of mechanisms adopted by S. patens to overcome salt and drought stress while maintaining relatively invariant leaf morphological traits and plant biomass. In particular, salt marsh plants experiencing severe water stress underwent greater osmoregulation and leaf hydraulic adjustment than dune plants. We also present the first experimental evidence for salt-mediated regulation of xylem hydraulic efficiency in a halophytic grass and suggest that it is an important functional trait allowing plants growing in saline habitats to cope with a restricted water supply. The functional plasticity of leaf water relations and xylem hydraulics emerges as a key trait underlying the competitive ability and invasive potential of S. patens.
Using biomimetic loggers to measure interspecific and microhabitat variation in body temperatures of rocky intertidal invertebrates
Authors: Lathlean Justin A. , Ayre David J. , Coleman Ross A. , Minchinton Todd E.
Published: November 2014

Until recently, marine scientists have relied heavily on satellite sea surface temperatures and terrestrial weather stations as indicators of the way in which the thermal environment, and hence the body temperatures of organisms, vary over spatial and temporal scales. We designed biomimetic temperature loggers for three species of rocky intertidal invertebrates to determine whether mimic body temperatures differ from the external environment and among species and microhabitats. For all three species, microhabitat temperatures were considerably higher than the body temperatures, with differences as great as 11.1°C on horizontal rocky substrata. Across microhabitats, daily maximal temperatures of the limpet Cellana tramoserica were on average 2.1 and 3.1°C higher than body temperatures of the whelk Dicathais orbita and the barnacle Tesseropora rosea respectively. Among-microhabitat variation in each species’ temperature was equally as variable as differences among species within microhabitats. Daily maximal body temperatures of barnacles placed on southerly facing vertical rock surfaces were on average 2.4°C cooler than those on horizontal rock. Likewise, daily maximal body temperatures of whelks were on average 3.1°C cooler within shallow rock pools than on horizontal rock. Our results provide new evidence that unique thermal properties and microhabitat preferences may be important determinants of species’ capacity to cope with climate change.
Temporal and spatial differences in the reproductive biology of the sea urchin Arbacia dufresnii
Authors: Epherra Lucia , Gil Damián G. , Rubilar Tamara , Perez-Gallo Soledad , Reartes M. Belén , Tolosano Javier A.
Published: November 2014

The reproductive cycle of Arbacia dufresnii was studied in two contrasting populations on the eastern coast of Patagonia (Nuevo Gulf and San Jorge Gulf) from January 2008 to August 2010. Sea urchins from San Jorge Gulf had larger test diameter and heavier gonads than did sea urchins from Nuevo Gulf. A. dufresnii showed an annual cycle in both populations, with gametogenesis occurring mainly in the autumn and the winter. An extended spawning period took place during the spring and the summer. Sea urchins from Nuevo Gulf had a strong seasonal pattern of reproduction, with presence of gonadal stages showing re-absortion and accumulation of reserves in nutritive cells at different seasons, whereas individuals from San Jorge Gulf had mature gametes during most of the year. Interannual variation of seawater temperature affected the gamete production and spawning duration in both populations. Higher temperatures during gametogenesis enhanced gonadal growth and gametes were released early. The major population differences found in gonadal cell composition highlight the plasticity in reproductive traits of A. dufresnii, and may be responsible for the wide distribution of A. dufresnii in different environments.
Challenges of assessing fire and burn severity using field measures, remote sensing and modelling
Authors: Morgan Penelope , Keane Robert E. , Dillon Gregory K. , Jain Theresa B. , Hudak Andrew T. , Karau Eva C. , Sikkink Pamela G. , Holden Zachary A. , Strand Eva K.
Published: November 2014

Comprehensive assessment of ecological change after fires have burned forests and rangelands is important if we are to understand, predict and measure fire effects. We highlight the challenges in effective assessment of fire and burn severity in the field and using both remote sensing and simulation models. We draw on diverse recent research for guidance on assessing fire effects on vegetation and soil using field methods, remote sensing and models. We suggest that instead of collapsing many diverse, complex and interacting fire effects into a single severity index, the effects of fire should be directly measured and then integrated into severity index keys specifically designed for objective severity assessment. Using soil burn severity measures as examples, we highlight best practices for selecting imagery, designing an index, determining timing and deciding what to measure, emphasising continuous variables measureable in the field and from remote sensing. We also urge the development of a severity field assessment database and research to further our understanding of causal mechanisms linking fire and burn severity to conditions before and during fires to support improved models linking fire behaviour and severity and for forecasting effects of future fires.
An accuracy assessment of the MTBS burned area product for shrub–steppe fires in the northern Great Basin, United States
Authors: Sparks Aaron M. , Boschetti Luigi , Smith Alistair M. S. , Tinkham Wade T. , Lannom Karen O. , Newingham Beth A.
Published: November 2014

Although fire is a common disturbance in shrub–steppe, few studies have specifically tested burned area mapping accuracy in these semiarid to arid environments. We conducted a preliminary assessment of the accuracy of the Monitoring Trends in Burn Severity (MTBS) burned area product on four shrub–steppe fires that exhibited varying degrees of within-fire patch heterogeneity. Independent burned area perimeters were derived through visual interpretation and were used to cross-compare the MTBS burned area perimeters with classifications produced using set thresholds on the Relativised differenced Normalised Burn Index (RdNBR), Mid-infrared Burn Index (MIRBI) and Char Soil Index (CSI). Overall, CSI provided the most consistent accuracies (96.3–98.6%), with only small commission errors (1.5–4.4%). MIRBI also had relatively high accuracies (92.2–97.9%) and small commission errors (2.1–10.8%). The MTBS burned area product had higher commission errors (4.3–15.5%), primarily due to inclusion of unburned islands and fingers within the fire perimeter. The RdNBR burned area maps exhibited lower accuracies (92.9–96.0%). However, the different indices when constrained by the MTBS perimeter provided variable results, with CSI providing the highest and least variable accuracies (97.4–99.1%). Studies seeking to use MTBS perimeters to analyse trends in burned area should apply spectral indices to constrain the final burned area maps. The present paper replaces a former paper of the same title (http://dx.doi.org/10.1071/WF13206), which was withdrawn owing to errors discovered in data analysis after the paper was accepted for publication.
Disruption of FAT10–MAD2 binding inhibits tumor progression
Authors: Theng Steven Setiawan , Wang Wei , Mah Way-Champ , Chan Cheryl , Zhuo Jingli , Gao Yun , Qin Haina , Lim Liangzhong , Chong Samuel S. , Song Jianxing , Lee Caroline G.
Published: November 2014

Significance

FAT10, a ubiquitin-like modifier, is an oncogene that interacts with mitotic arrest-deficient 2 (MAD2) and confers cellular malignancy. Here we identified the MAD2-binding residues of FAT10 and determined the first solution structure, to our knowledge, of the first FAT10 ubiquitin-like domain. Importantly, we demonstrated the proof-of-mechanism for a novel and specific drug-targeting strategy that entails the specific inhibition of the pathological activity of a therapeutic target but not its reported physiological function, thus minimizing undesirable side effects: Abrogation of the FAT10–MAD2 interaction curtailed tumor progression without affecting FAT10’s interaction with its other known physiological binding partners. This study presents a paradigm for drug targeting and paves the way for the development of a novel small-molecule anticancer inhibitor targeting the MAD2-binding interface of FAT10.
Mechanism of ganciclovir-induced chain termination revealed by resistant viral polymerase mutants with reduced exonuclease activity
Authors: Chen Han , Beardsley G. Peter , Coen Donald M.
Published: November 2014

Significance

Nucleoside analogues include important drugs that target DNA polymerases and cause chain termination. However, how ganciclovir, the first line of treatment for human cytomegalovirus infections, does this is unknown. Ganciclovir resistance is a serious clinical problem. Many ganciclovir-resistant isolates contain substitutions in the 3′–5′ exonuclease domain of the catalytic subunit of viral DNA polymerase. How these mutations confer resistance is a long-standing question. This study shows that both wild-type and exonuclease mutant polymerases incorporate ganciclovir into DNA and continue synthesis, but whereas the wild-type enzyme excises nucleotides two positions downstream of incorporated ganciclovir, the mutant enzymes do not, permitting chain extension. These results show how a therapeutically important drug causes chain termination and explain an unusual mechanism of drug resistance.
Functionally distinct
ERAP1
allotype combinations distinguish individuals with Ankylosing Spondylitis
Authors: Reeves Emma , Colebatch-Bourn Alexandra , Elliott Tim , Edwards Christopher J. , James Edward
Published: November 2014

Significance

The immune system performs surveillance to identify infected or cancerous cells through recognition of small protein fragments called antigenic peptides on their surface. To do this, the peptides must be cut to a specific length by an enzyme called endoplasmic reticulum aminopeptidase 1 (ERAP1). Variation in this enzyme has recently been linked to the inflammatory rheumatic disease Ankylosing Spondylitis (AS). We have found that ERAP1 is highly polymorphic in humans and that specific combinations of ERAP1 are found in people with AS. These disease-associated combinations have a reduced ability to generate peptides for presentation at the cell surface by MHC class I molecules, including HLA-B27. Understanding this finding may allow easier identification of individuals with AS and allow stratification into prognostic groups.
Elevated hippocampal resting-state connectivity underlies deficient neurocognitive function in aging
Authors: Salami Alireza , Pudas Sara , Nyberg Lars
Published: November 2014

Significance

Aging is accompanied by disruptive alterations in large-scale brain systems, such as the default mode network (DMN) and the associated hippocampus (HC) subsystem, which support higher cognitive functions. However, the exact form of DMN–HC alterations and concomitant memory deficits is largely unknown. We identified age-related decrements in resting-state functional connectivity of the cortical DMN, whereas elevated connectivity between the bilateral HC was found along with attenuated HC–cortical connectivity. Critically, elevated HC at rest restricts the degree to which HC interacts with other brain regions during memory tasks, and thus results in memory deficits. This study provides empirical evidence of how the relationship between the DMN and HC breaks down in aging and how such alterations underlie deficient mnemonic processing.
Actin stress in cell reprogramming
Authors: Guo Jun , Wang Yuexiu , Sachs Frederick , Meng Fanjie
Published: November 2014

Significance

Mechanical signaling plays many roles in cell physiology, including stem cell differentiation and reprogramming. To better understand the roles of mechanical forces in stem cells, we created genetically coded probes for actin that enables the direct measurement of forces in actin in living cells. This is the first force probe created for oligomeric proteins. We reprogrammed HEK-293 and Madin-Darby canine kidney cells into stem-like cells by culturing them on a soft substrate without using transcription factors. The mechanical properties of the microenvironment, and thus the local forces, promote cell reprogramming. Surprisingly, the cells showed close association of stemness to high tension in actin. Given the universal presence of actin in animal cells, the actin force probes have broad applications in biology.
ELAVL1 regulates alternative splicing of eIF4E transporter to promote postnatal angiogenesis
Authors: Chang Sung-Hee , Elemento Olivier , Zhang Jiasheng , Zhuang Zhen W. , Simons Michael , Hla Timothy
Published: November 2014

Significance

Angiogenesis, or new blood vessel formation, is critical not only for normal processes such as embryonic development but also for progression of diseases such as tumor growth, metastasis, and chronic inflammatory disease. This work elucidated a molecular mechanism that is important in postnatal angiogenesis in tumor growth and ischemia–reperfusion injury in the hind limb. Specifically, we identified a posttranscriptional gene regulatory mechanism that controls the activity of a potent suppressor of gene expression, named eIF4e transporter (4E-T). Alternative splicing of 4E-T controls the level of the active form of 4E-T, which suppresses gene expression in endothelial cells. This mechanism may be targeted to control angiogenesis-dependent diseases.
The cholesterol-dependent cytolysins pneumolysin and streptolysin O require binding to red blood cell glycans for hemolytic activity
Authors: Shewell Lucy K. , Harvey Richard M. , Higgins Melanie A. , Day Christopher J. , Hartley-Tassell Lauren E. , Chen Austen Y. , Gillen Christine M. , James David B. A. , Alonzo Francis , Torres Victor J. , Walker Mark J. , Paton Adrienne W. , Paton James C. , Jennings Michael P.
Published: November 2014

Significance

The pneumococcus accounts for 25% of deaths in children under 5 y of age in developing countries. One of the most important virulence factors expressed by this pathogen is the pore-forming toxin, pneumolysin (Ply), an example of a Gram-positive cholesterol-dependent cytolysin (CDC). We show that Ply interacts with the Lewis histo-blood group antigen sialyl LewisX and that blocking this interaction can protect RBCs from lysis. We also identify glycan receptors on RBCs for the CDC streptolysin O from group A streptococcus. Our study supports the emerging paradigm shift that CDCs have cellular receptors other than cholesterol that define target cell tropism.
Amazonian landscapes and the bias in field studies of forest structure and biomass
Authors: Marvin David C. , Asner Gregory P. , Knapp David E. , Anderson Christopher B. , Martin Roberta E. , Sinca Felipe , Tupayachi Raul
Published: November 2014

Significance

Although tropical forests absorb more carbon dioxide as biomass than any other terrestrial ecosystem, biomass estimates disagree substantially at landscape-to-regional scales. Current biomass maps rely upon field plots for extrapolations to larger scales, yet whether field plots accurately represent landscape-scale variables has not been assessed. To our knowledge, this is the first study to compare forest structural variables and aboveground biomass derived from field plots to those derived from their host landscapes using airborne 3D remote sensing. We found that typical field plots can produce substantially biased estimates and the number of plots needed to reduce this bias is impractical, positioning airborne remote sensing as a core tool for mapping forest structure and biomass across tropical landscapes.
Substrate recognition by the cell surface palmitoyl transferase DHHC5
Authors: Howie Jacqueline , Reilly Louise , Fraser Niall J. , Vlachaki Walker Julia M. , Wypijewski Krzysztof J. , Ashford Michael L. J. , Calaghan Sarah C. , McClafferty Heather , Tian Lijun , Shipston Michael J. , Boguslavskyi Andrii , Shattock Michael J. , Fuller William
Published: November 2014

Significance

Dynamic palmitoylation at the cell surface by the acyl transferase DHHC5 regulates a plethora of physiological processes, from endocytosis to synaptic plasticity. Here we report that DHHC5 is abundantly expressed in cell surface caveolar microdomains in cardiac muscle, and that the Na pump regulator phospholemman is a substrate for DHHC5. Palmitoylation of phospholemman C40 by DHHC5 reduces Na pump activity. DHHC5 interacts with phospholemman independent of its PSD-95/Discs-large/ZO-1 homology (PDZ) binding motif, via a region of its intracellular carboxyl tail that has not hitherto been implicated in substrate recognition. This suggests that it may be possible to selectively manipulate DHHC5 activity by blocking the recruitment of specific substrates to the active site by the carboxyl tail.
Electric fingerprint of voltage sensor domains
Authors: Souza Caio S. , Amaral Cristiano , Treptow Werner
Published: November 2014

Significance

A central paradigm in the subject of cellular excitability is whether or not a dynamic membrane voltage field contributes to the operation of voltage sensor proteins. This issue has challenged an entire generation of scientists because static and dynamic contributions of the field cannot be discriminated from electrophysiology measurements. The dilemma imposes that structure-based calculations are required to solve the issue. By following this approach, we report that reshaping or dynamics of the field does not impact significantly the domain energetics or operation. As such, the functional diversity of voltage sensors observed in nature originates from variations in the detailed atom–atom interactions of the domain (chemical free energy) rather than in its coupling with the membrane voltage.
Distinct roles of FKF1, GIGANTEA, and ZEITLUPE proteins in the regulation of CONSTANS stability in
Arabidopsis
photoperiodic flowering
Authors: Song Young Hun , Estrada Daniel A. , Johnson Richard S. , Kim Somi K. , Lee Sang Yeol , MacCoss Michael J. , Imaizumi Takato
Published: November 2014

Significance

In many plants, seasonal flowering is a crucial aspect of maximizing reproductive fitness. Changes in day length (or photoperiod) provide the most reliable cue that enables plants to anticipate approaching seasonal variation in the surrounding environment. The induction of the
FLOWERING LOCUS T
(
FT
) gene controlled by the light-stabilized CONSTANS (CO) protein is the key mechanism for photoperiodic flowering in
Arabidopsis thaliana
. The CO/FT module is highly conserved in many plant species, including major crops. In
Arabidopsis
, blue-light–signaling pathways are essential for the stabilization of CO protein. Here we show a unique role of GIGANTEA in photoperiodic flowering through the interactions with two homologous proteins, FLAVIN-BINDING, KELCH REPEAT, F-BOX1 and ZEITLUPE, which antagonistically control CO stability.
A mechanical-biochemical feedback loop regulates remodeling in the actin cytoskeleton
Authors: Stachowiak Matthew R. , Smith Mark A. , Blankman Elizabeth , Chapin Laura M. , Balcioglu Hayri E. , Wang Shuyuan , Beckerle Mary C. , O'Shaughnessy Ben
Published: November 2014

Significance

Cellular activities are regulated by signaling pathways in which information is transduced biochemically. Increasingly it is appreciated that regulation also involves mechanical signaling, where mechanical information is mechanotransduced into biochemical information. However, little is understood about the cooperation of mechanical and biochemical signaling in mixed pathways. We identified a pathway where the two types of signaling work in harmony to remodel actomyosin stress fibers in the cell’s cytoskeleton. We present evidence that expansion or contraction of fibers alters the actin filament overlap, a mechanical signal that is mechanotransduced into actin assembly or disassembly, which in turn alters the overlap. A mathematical model accurately describes our measurements and shows that this mechanical-biochemical feedback loop synchronizes actin remodeling with fiber length changes.
In vivo treatment of
Helicobacter pylori
infection with liposomal linolenic acid reduces colonization and ameliorates inflammation
Authors: Thamphiwatana Soracha , Gao Weiwei , Obonyo Marygorret , Zhang Liangfang
Published: November 2014

Significance

The use of a liposomal formulation of linolenic acid to kill
Helicobacter pylori
bacteria in the stomach represents a powerful treatment option for
H. pylori
infection, as well as its associated gastroduodenal diseases. Because the therapeutic agent is a natural compound found in common vegetable oils, such treatment is expected to be cost-effective compared with the existing antibiotic-based anti-
H. pylori
therapeutics. More important, the excellent antimicrobial efficacy, marked by significantly reduced in vivo bacterial colonization and inflammation, is achieved through rapid fusion of the nanoformulation with bacterial membrane, a mechanism known to overcome bacterial drug resistance. Similar therapeutic approaches can be developed to treat various types other bacterial infections.
Molecular architecture of the αβ T cell receptor–CD3 complex
Authors: Birnbaum Michael E. , Berry Richard , Hsiao Yu-Shan , Chen Zhenjun , Shingu-Vazquez Miguel A. , Yu Xiaoling , Waghray Deepa , Fischer Suzanne , McCluskey James , Rossjohn Jamie , Walz Thomas , Garcia K. Christopher
Published: November 2014

Significance

The T-cell receptor (TCR) does not signal on its own. Instead, it is constitutively associated with the CD3 coreceptors, which contain intracellular signaling motifs. Although antigen (Ag) recognition by the TCR and the activation of T cells after CD3 activation have been extensively studied, there is far less known about how the TCR relays the binding of Ag to initiate intracellular signaling. Detailed study of the eight-chain TCR–CD3 complex is hampered by limited structural information for how the components of the complex interact. We use complementary structural approaches to examine where the TCR–CD3 extracellular domains are placed relative to each other and the overall organization of the complex.
A calcium-dependent protease as a potential therapeutic target for Wolfram syndrome
Authors: Lu Simin , Kanekura Kohsuke , Hara Takashi , Mahadevan Jana , Spears Larry D. , Oslowski Christine M. , Martinez Rita , Yamazaki-Inoue Mayu , Toyoda Masashi , Neilson Amber , Blanner Patrick , Brown Cris M. , Semenkovich Clay F. , Marshall Bess A. , Hershey Tamara , Umezawa Akihiro , Greer Peter A. , Urano Fumihiko
Published: November 2014

Significance

Wolfram syndrome is an autosomal recessive disorder characterized by juvenile diabetes and neurodegeneration, and is considered a prototype of human endoplasmic reticulum (ER) disease. Wolfram syndrome is caused by loss of function mutations of Wolfram syndrome 1 or Wolfram syndrome 2 genes, which encode transmembrane proteins localized to the ER. Despite its rarity, Wolfram syndrome represents the best human disease model currently available to identify drugs and biomarkers associated with ER health. Furthermore, this syndrome is ideal for studying the mechanisms of ER stress-mediated death of neurons and β cells. Here we report that the pathway leading to calpain activation offers potential drug targets for Wolfram syndrome and substrates for calpain might serve as biomarkers for this syndrome.
Energetics of metastudtite and implications for nuclear waste alteration
Authors: Guo Xiaofeng , Ushakov Sergey V. , Labs Sabrina , Curtius Hildegard , Bosbach Dirk , Navrotsky Alexandra
Published: November 2014

Significance

Uranium peroxides, metastudtite and studtite, can be formed on exposure of UO
2
based nuclear fuels to water during geological disposal or as a result of reactor accidents. We report detailed structural and thermochemical analysis of the metastudtite decomposition process. The thermodynamic data confirm the irreversible transformation from studtite to metastudtite and show that metastudtite can be a major oxidized corrosion product at the surface of UO
2
and contribute a significant pathway to dissolution. The prevalence of metastudtite may require additional tailoring of waste forms to minimize this dissolution pathway for uranium.
The state of the article
Authors: Winward John
Published: November 2014

English articles represent one of the most challenging areas of second language acquisition for learners whose L1 lacks articles. The two studies presented here examine the developmental sequence of acquisition, the first through a cross-sectional analysis of Thai learners at different levels of overall English proficiency, the second through a longitudinal experiment in which learners were exposed to semantically-tailored tokens of article use, but without any explicit or meta-linguistic instruction. It is argued that the data do not show evidence of abrupt parameter resetting. Instead, the developmental patterns fit well with Yang’s variational model of acquisition. Keywords: L2 acquisition; article systems; determiners; definiteness; specificity
Developments in the acquisition of Wh-interrogatives in Cypriot Greek
Authors: Varnava Marina , Grohmann Kleanthes K.
Published: November 2014

This cross-sectional study investigates the acquisition of the interpretation of syntactic and semantic aspects ofwh-questions by Cypriot Greek-speaking children aged 4 to 9 years. Two experimental tools were employed, a question–picture-matching task examining the comprehension of D-linked and non-D-linked questions for subject and object, and a question-after-picture task examining the comprehension of the notion of exhaustivity in single and multiplewh-questions. The results from these experiments are interpreted in light of current theoretical advances and cross-linguistic comparisons. The apparent discrepancies found in the development of Greek Cypriot children’s comprehension ofwh-questions and exhaustivity are put in perspective with their particular linguistic environment – diglossia, in which children grow up with two varieties, Cypriot Greek and Standard Modern Greek. Keywords: bilectalism; D(iscourse)-linking; first language acquisition; multiple wh-questions; single wh-questions
How mixed is a ‘mixed’ system?
Authors: Tsiplakou Stavroula
Published: November 2014

Cypriot and Standard Greek still stand in a diglossic relationship; however, recent work on Cypriot Greek points to ongoing processes oflevellingof local sub-varieties and the emergence of a pancypriotkoiné. This paper explores patterns of structural mixing between Standard and Cypriot Greek in the Cypriotkoiné. The data indicate that structural mixing is mostly achieved through morphological choices, while Cypriot phonology and syntax remain largely intact. The fact that morphology has this capacity of a ‘buffer’ between two presumably competing grammatical systems provides a strong parallel to interlanguage phenomena and a potential account of why the two systems are prevented from merging. Keywords: competing grammars; Cypriot Greek; diglossia; koiné; levelling; Standard Greek
Television news consumption and public attitudes towards immigration: a multi-level approach / Consumo de información televisiva y actitudes publicas hacia la inmigración: un enfoque multinivel
Authors: Álvarez-Gálvez Javier
Published: November 2014

This paper analyses the association between TV news consumption and public attitudes towards immigration. A multi-level model is used to study the complex relationship between TV news consumption, how the media treat immigration and public attitudes towards minority groups based on a survey of university students. Multi-level analysis results show the impact of aggregate consumption of TV news on the perception of the current immigration phenomenon and the cognitive/affective components of attitude. It also demonstrates the usefulness of this analytical approach for understanding the processes that describe the relationship between the media and attitudes towards immigration.
Absence of Handling-Induced Saprolegnia Infection in Juvenile Rainbow Trout with Implications for Catch-and-Release Angling
Authors: Schwabe Martin , Meinelt Thomas , Phan Thuy M. , Cooke Steven J. , Arlinghaus Robert
Published: November 2014

Catch-and-release angling is common in recreational fisheries. During handling and dehooking, fish are subjected to stress and dermal injuries, which may result in infections by pathogens after the fish is released. The objective of this study was to evaluate the consequences of common handling practices used by anglers on the postrelease behavior and fate, particularly the susceptibility to disease, of undersized Rainbow Trout Oncorhynchus mykiss. Behavior immediately following capture and subsequent release of fish was examined in a 40-L container, and long-term fate was studied for 2 weeks in tanks incubated with Saprolegnia parasitica zoospores. Trout were behaviorally impaired as indicated by the ease of being netted following the simulated fight associated with catch and release, but there were no further behavioral impacts due to subsequent handling. None of the Rainbow Trout developed fungal infections nor was any significant mortality observed after 2 weeks; only 1 out of 137 fish died. Our data indicate that juvenile hatchery-reared Rainbow Trout have a high resilience to Saprolegnia infection handling-induced stress.

Received February 9, 2014; accepted August 25, 2014
Phenotypic and physiological responses of two willow varieties to salt stress
Authors: Wang Ying , Yuan Huwei , Li Min , Li Yujuan , Ma Xiangjian , Tan Feng , Zhang Jian
Published: November 2014

Willows are one of the most important landscaping, biofuel, and raw timber tree species in the world. Cultivating fast-growing, salt-tolerant willow varieties is an effective way to balance wood supply and demand in China. This paper presents a comparative evaluation of the phenotypic development and physiological responses of two willow varieties,SalixL0911 (L0911) andSalix matsudana(SM), to salt stress. L0911 developed more biomass than SM and demonstrated higher tolerance to long-term exposures to NaCl-salinity. The two varieties demonstrated similar trends of physiological changes under salt stress, but the extent of the induced responses were higher in L0911, suggesting the involvement of specific responses in the salt-tolerant mechanism. Specifically, the activities of superoxide dismutase, peroxidase, soluble proteins and proline contents were higher in L0911 compared to SM, and the content of malondialdehyde and Na+and Na+/K+ratios were lower, demonstrating that the improved tolerance to salinity in L0911 is based on antioxidant response and improved ion selectivity.
Effects of Sodium Chloride and Long-Term, Low-Concentration Exposures to Hydrogen Peroxide on New Zealand Mud Snails
Authors: Oplinger Randall W , Wagner Eric J
Published: November 2014

New Zealand mud snails Potamopyrgus antipodarum (NZMS) are an invasive species and keeping NZMS out of hatcheries is important because the snail can be spread through the stocking of fish. We conducted a series of experiments to evaluate the effectiveness of using hydrogen peroxide to kill NZMS and sodium chloride to force NZMS to withdraw into their shells. The lowest concentrations of hydrogen peroxide that produced 100% mortality of NZMS were 750 mg/L for a 24-h exposure and and 75 mg/L for a 96-h exposure. We found that NZMS treated with sodium chloride withdrew into their shell and released from the substrate. Treatments with sodium chloride (717 mg/L) caused 70% of NZMS to withdraw into their shells and release from the substrate within the first minute of exposure, which could be beneficial in flushing them from a hatchery system provided there is sufficient discharge.
Cytomegalovirus generates long-lived antigen-specific NK cells with diminished bystander activation to heterologous infection
Authors: Min-Oo Gundula , Lanier Lewis L.
Published: November 2014

Natural killer (NK) cells play a key role in the host response to cytomegalovirus (CMV) and can mediate an enhanced response to secondary challenge with CMV. We assessed the ability of mouse CMV (MCMV)–induced memory Ly49H+ NK cells to respond to challenges with influenza, an acute viral infection localized to the lung, and Listeria monocytogenes, a systemic bacterial infection. MCMV-memory NK cells did not display enhanced activation or proliferation after infection with influenza or Listeria, as compared with naive Ly49H+ or Ly49H− NK cells. Memory NK cells also showed impaired activation compared with naive cells when challenged with a mutant MCMV lacking m157, highlighting their antigen-specific response. Ex vivo, MCMV-memory NK cells displayed reduced phosphorylation of STAT4 and STAT1 in response to stimulation by IL-12 and type I interferon (IFN), respectively, and IFN-γ production was reduced in response to IL-12 + IL-18 compared with naive NK cells. However, costimulation of MCMV-memory NK cells with IL-12 and m157 antigen rescues their impaired response compared with cytokines alone. These findings reveal that MCMV-primed memory NK cells are diminished in their response to cytokine-driven bystander responses to heterologous infections as they become specialized and antigen-specific for the control of MCMV upon rechallenge.
Signaling in the Brain: In Search of Functional Units
Authors: Cao Rosa
Published: November 2014

What are the functional units of the brain? If the function of the brain is to process information-carrying signals, then the functional units will be the senders and receivers of those signals. Neurons have been the default candidate, with action potentials as the signals. But there are alternatives: synapses fit the action potential picture more cleanly, and glial activities (e.g., in astrocytes) might also be characterized as signaling. Are synapses or nonneuronal cells better candidates to play the role of functional units? Will informational signaling still be the best model for brain function if we move beyond the neuron doctrine?