bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetocaloric effect and magnetothermopower in the room temperature ferromagnet Pr0.6Sr0.4MnO3
Authors: Maheswar Repaka D. V. , Tripathi T. S. , Aparnadevi M. , Mahendiran R.
Published: December 2012

We have investigated magnetization (M), magnetocaloric effect (MCE), and magnetothermopower (MTEP) in polycrystalline Pr0.6Sr0.4MnO3, which shows a second-order paramagnetic to ferromagnetic transition near room temperature (TC = 305 K). However, field-cooled M(T) within the long range ferromagnetic state shows an abrupt decrease at TS = 86 K for μ0H < 3 T. The low temperature transition is first-order in nature as suggested by the hysteresis in M(T) and exothermic/endothermic peaks in differential thermal analysis for cooling and warming cycles. The anomaly at TS is attributed to a structural transition from orthorhombic to monoclinic phase. The magnetic entropy change (ΔSm = Sm(μ0 H)-Sm(0)) shows a negative peak at TC (normal MCE) and a positive spike (inverse MCE) at TS. ΔSm = −2.185 J/kg K (−3.416 J/kg K) with refrigeration capacity RC = 43.4 J/kg (103.324 J/kg) for field change of μ0ΔH = 1.5 T (3 T) at TC = 304 K is one of the largest values reported in manganites near room temperature. Thermopower (Q) is negative from 350 K to 20 K, which shows a rapid decrease at TC and a small cusp around TS in zero field. The MTEP [ΔQ/Q(0)] reaches a maximum value of 25% for μ0ΔH = 3 T around TC, which is much higher than 15% dc magnetoresistance for the same field change. A linear relation between MTEP and magnetoresistance and between ΔSm and ΔQ are found near TC. Further, ac magnetotransport in low dc magnetic fields (μ0 H ≤ 0.1 T), critical analysis of the paramagnetic to ferromagnetic transition, and scaling behavior of ΔSm versus a reduced temperature under different magnetic fields are also reported. Coexistence of large magnetic entropy change and magnetothermopower around room temperature makes this compound interesting for applications.
The role of confinement on stress-driven grain boundary motion in nanocrystalline aluminum thin films
Authors: Gianola Daniel S. , Farkas Diana , Gamarra Martin , He Mo-rigen
Published: December 2012

3D molecular dynamics simulations are performed to investigate the role of microstructural confinement on room temperature stress-driven grain boundary (GB) motion for a general population of GBs in nanocrystalline Al thin films. Detailed analysis and comparison with experimental results reveal how coupled GB migration and GB sliding are manifested in realistic nanoscale networks of GBs. The proximity of free surfaces to GBs plays a significant role in their mobility and results in unique surface topography evolution. We highlight the effects of microstructural features, such as triple junctions, as constraints to otherwise uninhibited GB motion. We also study the pinning effects of impurities segregated to GBs that hinder their motion. Finally, the implications of GB motion as a deformation mechanism governing the mechanical behavior of nanocrystalline materials are discussed.
Magnetization reversal in graded anisotropy Co/Pt multilayers: A first order reversal curve study
Authors: Markou A. , Panagiotopoulos I. , Bakas T. , Postolache P. , Stoleriu L. , Stancu A.
Published: December 2012

The magnetization reversal in graded anisotropy Co/Pt multilayers is studied by first order reversal curve (FORC) diagrams. The graded profile influences the nucleation field in thin films. In thicker films (above the threshold value for stripe domain formation), its effect is masked, as the loop shape depends sensitively on the ratio of film thickness to a characteristic length defined by domain wall and demagnetizing energies. For such thick samples, the FORC distribution shows two positive features that correspond to domain nucleation and annihilation. Between these two peaks, no other distinct features are visible, due to the high reversibility of domain pattern characteristics. In thin continuous films, a marked feature that corresponds to nucleation is accompanied by two features of opposite polarity characteristic of two-phase interactions. In nanostructured samples, the domain effects are suppressed and the FORC is dominated by a single feature elongated along the interaction axis.
Ballistic thermal transport contributed by the in-plane waves in a quantum wire modulated with an acoustic nanocavity
Authors: Yi Guo-Jun , Xie Zhong-Xiang , Chen Ke-Qiu , Tang Li-Ming , Chen Xiao-Hua
Published: December 2012

We investigate ballistic thermal transport contributed by the in-plane waves in a quantum wire modulated with an acoustic nanocavity. Here, the numerical calculations for two transmitted components (P wave and SV wave) are made to consider the mode conversion. Results show for the P wave component that the universal quantum thermal conductance can be observed in spite of structural details in the low temperature limit, and then the thermal conductance decreases with increasing temperature. However, for the SV wave component, the thermal conductance increases from zero monotonically with temperature. These indicate the mode conversion is directly proportional to the temperature. In addition, it is found that the mode conversion sensitively depend upon the incident frequency, the index of the modes as well as structural parameters. A brief analysis of these results is given.
A full computation-relevant topological dynamics classification of elementary cellular automata
Authors: Schüle Martin , Stoop Ruedi
Published: December 2012

Cellular automata are both computational and dynamical systems. We give a complete classification of the dynamic behaviour of elementary cellular automata (ECA) in terms of fundamental dynamic system notions such as sensitivity and chaoticity. The “complex” ECA emerge to be sensitive, but not chaotic and not eventually weakly periodic. Based on this classification, we conjecture that elementary cellular automata capable of carrying out complex computations, such as needed for Turing-universality, are at the “edge of chaos.”
Broad frequency and amplitude control of vibration in freestanding graphene via scanning tunneling microscopy with calculated dynamic pseudo-magnetic fields
Authors: Xu P. , Schoelz J. K. , Barber S. D. , Ackerman M. L. , Thibado P. M.
Published: December 2012

A technique to locally generate mechanical vibrations in freestanding graphene using scanning tunneling microscopy (STM) is presented. The frequency of the mechanical vibrations is tuned over nearly four decades and is centered around 10 Hz. The amplitude of the vibrations also changes over nearly three decades centered on 1 nm. The oscillating motion is generated in two ways: first, by scanning the STM tip on the surface and second, by scanning the bias voltage on the STM tip. The frequency and amplitude of the displaced freestanding graphene is quantitatively transformed to the frequency and strength of the locally generated pseudo-magnetic field for our specific geometry.
Optical studies of random disorder of colloidal photonic crystals and its evolution in evaporation induced self-assembly
Authors: Wang Jinze , Yang Lei , Lin Dongfeng , Luo Yanhong , Li Dongmei , Meng Qingbo
Published: December 2012

Self-assembled photonic structures have been under theoretical and experimental study for decades, whereas previous theories on optical properties were mainly concerned with perfect structure or some certain limited kinds of disordered photonic crystals (PCs), making them unsuitable for characterizing the real self-assembled PCs. In order to improve our understanding of the mechanism of self-assembly and provide more crucial clues to further grow perfect crystals, we extended previous widely used scalar wave approximation (SWA), making it be able to characterize long-range disorder (β) and short-range disorder (α) in PCs synthetically in a simple and effective way. Excellent agreement with in situ observed reflectance of evaporation induced self-assembled colloidal photonic crystals (CPCs) was obtained, demonstrating that the introduction of the parameters α and β in SWA can successfully characterize the disorder in self-assembled CPCs. Furthermore, extended SWA was further used to study the disorder formation in self-assembly, and it was found that during growing stage both β and α drop down, whereas in drying stage β stays nearly unchanged while α increases significantly. It turned out that the growing stage of self-assembly is a stage when the structure transforms from disordered to ordered one, and growth induced disorder mainly arises in drying stage. The results obtained provide an insight into the growth mechanisms of self-assembly and theoretical basis for characterizing optical properties of disordered PCs.
Particle lifetime in cylindrical cavity with absorbing spot on the wall: Going beyond the narrow escape problem
Authors: Dagdug Leonardo , Berezhkovskii Alexander M. , Bezrukov Sergey M.
Published: December 2012

The mean lifetime of a particle diffusing in a cylindrical cavity with a circular absorbing spot on the cavity wall is studied analytically as a function of the spot radius, its location on the wall, the particle initial position, and the cavity shape determined by its length and radius. When the spot radius tends to zero our formulas for the mean lifetime reduce to the result given by the solution of the narrow escape problem, according to which the mean lifetime is proportional to the ratio of the cavity volume to the spot radius and is independent of the cavity shape, the spot location on the cavity wall, and the particle starting point, assuming that this point is not too close to the spot. When the spot radius is not small enough, the asymptotic narrow escape formula for the mean lifetime fails, and one should use more general formulas derived in the present study. To check the accuracy and to establish the range of applicability of the formulas, we compare our theoretical predictions with the results of Brownian dynamics simulations.
Femtosecond laser induced surface deformation in multi-dimensional data storage
Authors: Hu Yanlei , Chen Yuhang , Li Jiawen , Hu Daqiao , Chu Jiaru , Zhang Qijin , Huang Wenhao
Published: December 2012

We investigate the surface deformation in two-photon induced multi-dimensional data storage. Both experimental evidence and theoretical analysis are presented to demonstrate the surface characteristics and formation mechanism in azo-containing material. The deformation reveals strong polarization dependence and has a topographic effect on multi-dimensional encoding. Different stages of data storage process are finally discussed taking into consideration the surface deformation formation.
Efficient coupler between silicon photonic and metal-insulator-silicon-metal plasmonic waveguides
Authors: Emboras A. , Briggs R. M. , Najar A. , Nambiar S. , Delacour C. , Grosse Ph. , Augendre E. , Fedeli J. M. , de Salvo B. , Atwater H. A. , Espiau de Lamaestre R.
Published: December 2012

We report the experimental realization of a compact, efficient coupler between silicon waveguides and vertical metal-insulator-silicon-metal (MISM) plasmonic waveguides. Devices were fabricated using complementary metal-oxide-silicon technology processes, with copper layers that support low-loss plasmonic modes in the MISM structures at a wavelength of 1550 nm. By implementing a short (0.5 μm) optimized metal-insulator-silicon-insulator structure inserted between the photonic and plasmonic waveguide sections, we demonstrate experimental coupling loss of 2.5 dB, despite the high optical confinement of the MISM mode and mismatch with the silicon waveguide mode.
Vertical minority carrier electron transport in p-type InAs/GaSb type-II superlattices
Authors: Umana-Membreno G. A. , Klein B. , Kala H. , Antoszewski J. , Gautam N. , Kutty M. N. , Plis E. , Krishna S. , Faraone L.
Published: December 2012

Vertical minority carrier electron transport parameters in p-type InAs/GaSb type-II superlattices for long wavelength infrared (LWIR) detection have been extracted from magnetic field dependent geometrical magneto-resistance. The measurements, performed at low electric fields and at magnetic field intensities up to 12 T, exhibited multiple-carrier conduction characteristics that required mobility spectrum analysis for the extraction of individual carrier mobilities and concentrations. Within the common operating temperature range for LWIR photodiodes (80 to 150 K), the conductivity was found to be dominated by three distinct carriers, attributed to majority holes (μ=280±27 cm2/Vs), minority electrons (μ=2,460±75 cm2/Vs), and parasitic sidewall inversion layer electrons (μ=930±55 cm2/Vs). A miniband energy gap of 140 ± 15 meV for the 14/7-monolayer InAs/GaSb superlattice was estimated from the thermal activation of the minority carrier electron density.
The effect of native oxide on ion-sputtering-induced nanostructure formation on GaSb surfaces
Authors: El-Atwani Osman , Allain J. P. , Suslova Anastassiya
Published: December 2012

We have investigated the influence of native oxides on ion-sputtering-induced nanostructure formation on GaSb using in situ low energy ion scattering spectroscopy (LEISS) and X-ray photoelectron spectroscopy (XPS). Comparing an oxygen-free sample with a native oxide sample, LEISS and XPS reveal the effect of oxygen in generating higher surface Ga fractions during early stages (fluences of 1 × 1015–1 × 1016 cm−2) of low energy (<100 eV) Ar+ irradiation. Enhanced surface Ga and Ga2O3 fractions were also observed on “oxide free” samples exposed to air following irradiation. The results suggest preferential Ga oxidation and segregation on the top of the amorphous layer if oxygen is present on the surface. In addition, the native oxide also increases the fluence threshold for nanopatterning of GaSb surfaces by almost a factor of four during low energy irradiation.
Spatial and orientational control of liquid crystal alignment using a surface localized polymer layer
Authors: Lu Lu , Sergan Tatiana , Sergan Vassili , Bos Philip J.
Published: December 2012

We present an alignment method for the surface contacting liquid crystal (LC) director. This method allows complete control of the polar pretilt angle as a function of position in a liquid crystal device, and has the potential of controlling the azimuthal orientation of LC. Important considerations of this method are to form a thin layer of reactive monomers at the LC cell interior surface, and to control the deleterious effects of flow due to polymerization induced concentration gradients. To achieve these, the voltage and frequency of the applied electric field and the UV intensity during the polymerization process are significant.
Spectroscopic temperature measurements of air breakdown plasma using a 110 GHz megawatt gyrotron beam
Authors: Hummelt J. S. , Shapiro M. A. , Temkin R. J.
Published: December 2012

Temperature measurements are presented of a non-equilibrium air breakdown plasma using optical emission spectroscopy. A plasma is created with a focused 110 GHz 3 μs pulse gyrotron beam in air that produces power fluxes exceeding 1 MW/cm2. Rotational and vibrational temperatures are spectroscopically measured over a pressure range of 1–100 Torr as the gyrotron power is varied above threshold. The temperature dependence on microwave field as well as pressure is examined. Rotational temperature measurements of the plasma reveal gas temperatures in the range of 300–500 K and vibrational temperatures in the range of 4200–6200 K. The vibrational and rotational temperatures increase slowly with increasing applied microwave field over the range of microwave fields investigated.
Preparation of atomically flat SrTiO3 surfaces using a deionized-water leaching and thermal annealing procedure
Authors: Connell J. G. , Isaac B. J. , Ekanayake G. B. , Strachan D. R. , Seo S. S. A.
Published: December 2012

We report that a deionized water leaching and thermal annealing technique can be effective for preparing atomically flat and singly terminated surfaces of single crystalline SrTiO3 substrates. After a two-step thermal-annealing and deionized-water leaching procedure, topography measured by atomic force microscopy shows the evolution of substrates from a rough to step-terraced surface structure. Lateral force microscopy confirms that the atomically flat surfaces are singly terminated. Moreover, this technique can be used to remove excessive strontium oxide or hydroxide composites segregated on the SrTiO3 surface. This acid-etchant-free technique facilitates the preparation of atomically aligned SrTiO3 substrates, which promotes studies on two-dimensional physics of complex oxide interfaces.
Energy band alignment of InGaZnO4/Si heterojunction determined by x-ray photoelectron spectroscopy
Authors: Xie Zhang-Yi , Lu Hong-Liang , Xu Sai-Sheng , Geng Yang , Sun Qing-Qing , Ding Shi-Jin , Wei Zhang David
Published: December 2012

X-ray photoelectron spectroscopy was utilized to determine the valence band offset (ΔEV) of the InGaZnO4 (IGZO)/Si heterojunction. The IGZO films were grown on Si (100) using radio frequency magnetron sputtering. A value of ΔEV = 2.53 eV was obtained by using In 3d5/2, Ga 2p3/2 core energy levels as references. Taking into consideration the experimental band gap of 3.20 eV of the IGZO, this would result in a conduction band offset ΔEC = 0.45 eV in this heterostructure.
Potential impact of microbial activity on the oxidant capacity and organic carbon budget in clouds
Authors: Vaïtilingom Mickael , Deguillaume Laurent , Vinatier Virginie , Sancelme Martine , Amato Pierre , Chaumerliac Nadine , Delort Anne-Marie
Published: December 2012

Within cloud water, microorganisms are metabolically active and, thus, are expected to contribute to the atmospheric chemistry. This article investigates the interactions between microorganisms and the reactive oxygenated species that are present in cloud water because these chemical compounds drive the oxidant capacity of the cloud system. Real cloud water samples with contrasting features (marine, continental, and urban) were taken from the puy de Dôme mountain (France). The samples exhibited a high microbial biodiversity and complex chemical composition. The media were incubated in the dark and subjected to UV radiation in specifically designed photo-bioreactors. The concentrations of H2O2, organic compounds, and the ATP/ADP ratio were monitored during the incubation period. The microorganisms remained metabolically active in the presence of●OH radicals that were photo-produced from H2O2. This oxidant and major carbon compounds (formaldehyde and carboxylic acids) were biodegraded by the endogenous microflora. This work suggests that microorganisms could play a double role in atmospheric chemistry; first, they could directly metabolize organic carbon species, and second, they could reduce the available source of radicals through their oxidative metabolism. Consequently, molecules such as H2O2would no longer be available for photochemical or other chemical reactions, which would decrease the cloud oxidant capacity.
Pattern formation of Rho GTPases in single cell wound healing
Authors: Simon Cory M. , Vaughan Emily M. , Bement William M. , Edelstein-Keshet Leah
Published: December 2012

The Rho GTPases—Rho, Rac, and Cdc42—control an enormous variety of processes, many of which reflect activation of these GTPases in spatially confined and mutually exclusive zones. By using mathematical models and experimental results to establish model parameters, we analyze the formation and segregation of Rho and Cdc42 zones during Xenopus oocyte wound repair and the role played by Abr, a dual guanine nucleotide exchange factor–GTPase-activating protein, in this process. The Rho and Cdc42 zones are found to be best represented as manifestations of spatially modulated bistability, and local positive feedback between Abr and Rho can account for the maintenance and dynamic properties of the Rho zone. In contrast, the invocation of an Abr-independent positive feedback loop is required to account for Cdc42 spatial bistability. In addition, the model replicates the results of previous in vivo experiments in which Abr activity is manipulated. Further, simulating the model with two closely spaced wounds made nonintuitive predictions about the Rho and Cdc42 patterns; these predictions were confirmed by experiment. We conclude that the model is a useful tool for analysis of Rho GTPase signaling and that the Rho GTPases can be fruitfully considered as components of intracellular pattern formation systems.
CD81 regulates cell migration through its association with Rac GTPase
Authors: Tejera Emilio , Rocha-Perugini Vera , López-Martín Soraya , Pérez-Hernández Daniel , Bachir Alexia I. , Horwitz Alan Rick , Vázquez Jesús , Sánchez-Madrid Francisco , Yáñez-Mo María
Published: December 2012

CD81 is a member of the tetraspanin family that has been described to have a key role in cell migration of tumor and immune cells. To unravel the mechanisms of CD81-regulated cell migration, we performed proteomic analyses that revealed an interaction of the tetraspanin C-terminal domain with the small GTPase Rac. Direct interaction was confirmed biochemically. Moreover, microscopy cross-correlation analysis demonstrated the in situ integration of both molecules into the same molecular complex. Pull-down experiments revealed that CD81-Rac interaction was direct and independent of Rac activation status. Knockdown of CD81 resulted in enhanced protrusion rate, altered focal adhesion formation, and decreased cell migration, correlating with increased active Rac. Reexpression of wild-type CD81, but not its truncated form lacking the C-terminal cytoplasmic domain, rescued these effects. The phenotype of CD81 knockdown cells was mimicked by treatment with a soluble peptide with the C-terminal sequence of the tetraspanin. Our data show that the interaction of Rac with the C-terminal cytoplasmic domain of CD81 is a novel regulatory mechanism of the GTPase activity turnover. Furthermore, they provide a novel mechanism for tetraspanin-dependent regulation of cell motility and open new avenues for tetraspanin-targeted reagents by the use of cell-permeable peptides.
Assessment of Risk of Bleeding From Esophageal Varices During Management of Biliary Atresia in Children
Authors: Wanty Catherine , Helleputte Thibault , Smets Françoise , Sokal Etienne M. , Stephenne Xavier
Published: December 2012

Objectives:

The management of esophageal varices (EV) in children experiencing biliary atresia (BA) remains controversial. Recent studies in children proposed initiating a prophylactic treatment in patients with severe (grade III) EV and/or EV associated with red color signs. Our study was aimed at assessing the risk of bleeding from EV in a series of patients with BA, identifying risk factors for bleeding to develop a predictive model of bleeding.

Methods:

This was a retrospective study including 83 eligible patients with BA. Clinical, ultrasonographic, endoscopic, and laboratory parameters were studied from the beginning of medical management up to the occurrence of upper gastrointestinal bleeding. In patients not presenting any bleeding, data were analyzed until liver transplantation, endoscopic treatment of EV was performed, or last follow‐up. Risk factors were investigated using univariate and multivariate statistical analyses.

Results:

Seventeen of 83 patients (20%) presented gastrointestinal bleeding, with a median age of 9.5 months (6–50 months). In univariate and multivariate analyses, high‐grade EV, red color signs on endoscopic examination, and low fibrinogen levels, at first endoscopy, were identified as risk factors for bleeding. When tested in >10,000 different models, these 3 variables appeared to play the most significant role in predicting bleeding.

Conclusions:

Our study confirmed that grade III EV and red color signs are risk factors for bleeding in patients followed up for BA. We identified low fibrinogen levels as an additional risk factor. The relevance of these 3 factors to predict bleeding from EV requires validation in a prospective study.
Patulibacter medicamentivorans sp. nov., isolated from activated sludge of a wastewater treatment plant
Authors: Almeida Bárbara , Vaz-Moreira Ivone , Schumann Peter , Nunes Olga C. , Carvalho Gilda , Crespo Maria T. Barreto
Published: December 2012

A Gram-positive, aerobic, non-motile, non-endospore-forming rod-shaped bacterium with ibuprofen-degrading capacity, designated strain I11T, was isolated from activated sludge from a wastewater treatment plant. The major respiratory quinone was demethylmenaquinone DMK-7, C18 : 1 cis9 was the predominant fatty acid, phosphatidylglycerol was the predominant polar lipid, the cell wall contained meso-diaminopimelic acid as the diagnostic diamino acid and the G+C content of the genomic DNA was 74.1 mol%. On the basis of 16S rRNA gene sequence analysis, the closest phylogenetic neighbours of strain I11T were

Patulibacter ginsengiterrae

CECT 7603T (96.8 % similarity),

Patulibacter minatonensis

DSM 18081T (96.6 %) and

Patulibacter americanus

DSM 16676T (96.6 %). Phenotypic characterization supports the inclusion of strain I11T within the genus

Patulibacter (phylum Actinobacteria)

. However, distinctive features and 16S rRNA gene sequence analysis suggest that is represents a novel species, for which the name Patulibacter medicamentivorans sp. nov. is proposed. The type strain is I11T ( = DSM 25962T = CECT 8141T).
The medial dorsal thalamic nucleus and the medial prefrontal cortex of the rat function together to support associative recognition and recency but not item recognition
Authors: Cross Laura , Brown Malcolm W. , Aggleton John P. , Warburton E. Clea
Published: December 2012

In humans recognition memory deficits, a typical feature of diencephalic amnesia, have been tentatively linked to mediodorsal thalamic nucleus (MD) damage. Animal studies have occasionally investigated the role of the MD in single-item recognition, but have not systematically analyzed its involvement in other recognition memory processes. In Experiment 1 rats with bilateral excitotoxic lesions in the MD or the medial prefrontal cortex (mPFC) were tested in tasks that assessed single-item recognition (novel object preference), associative recognition memory (object-in-place), and recency discrimination (recency memory task). Experiment 2 examined the functional importance of the interactions between the MD and mPFC using disconnection techniques. Unilateral excitotoxic lesions were placed in both the MD and the mPFC in either the same (MD + mPFC Ipsi) or opposite hemispheres (MD + mPFC Contra group). Bilateral lesions in the MD or mPFC impaired object-in-place and recency memory tasks, but had no effect on novel object preference. In Experiment 2 the MD + mPFC Contra group was significantly impaired in the object-in-place and recency memory tasks compared with the MD + mPFC Ipsi group, but novel object preference was intact. Thus, connections between the MD and mPFC are critical for recognition memory when the discriminations involve associative or recency information. However, the rodent MD is not necessary for single-item recognition memory.
miR156 and miR390 Regulate tasiRNA Accumulation and Developmental Timing in Physcomitrella patens
Authors: Cho Sung Hyun , Coruh Ceyda , Axtell Michael J.
Published: December 2012

microRNA156 (miR156) affects developmental timing in flowering plants. miR156 and its target relationships with members of the SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) gene family appear universally conserved in land plants, but the specific functions of miR156 outside of flowering plants are unknown. We find that miR156 promotes a developmental change from young filamentous protonemata to leafy gametophores in the moss Physcomitrella patens, opposite to its role as an inhibitor of development in flowering plants. P.  patens miR156 also influences accumulation of trans-acting small interfering RNAs (tasiRNAs) dependent upon a second ancient microRNA, miR390. Both miR156 and miR390 directly target a single major tasiRNA primary transcript. Inhibition of miR156 function causes increased miR390-triggered tasiRNA accumulation and decreased accumulation of tasiRNA targets. Overexpression of miR390 also caused a slower formation of gametophores, elevated miR390-triggered tasiRNA accumulation, and reduced level of tasiRNA targets. We conclude that a gene regulatory network controlled by miR156, miR390, and their targets controls developmental change in P.  patens. The broad outlines and regulatory logic of this network are conserved in flowering plants, albeit with some modifications. Partially conserved small RNA networks thus influence developmental timing in plants with radically different body plans.
A MAPK Cascade Downstream of ERECTA Receptor-Like Protein Kinase Regulates Arabidopsis Inflorescence Architecture by Promoting Localized Cell Proliferation
Authors: Meng Xiangzong , Wang Huachun , He Yunxia , Liu Yidong , Walker John C. , Torii Keiko U. , Zhang Shuqun
Published: December 2012

Spatiotemporal-specific cell proliferation and cell differentiation are critical to the formation of normal tissues, organs, and organisms. The highly coordinated cell differentiation and proliferation events illustrate the importance of cell–cell communication during growth and development. In Arabidopsis thaliana, ERECTA (ER), a receptor-like protein kinase, plays important roles in promoting localized cell proliferation, which determines inflorescence architecture, organ shape, and size. However, the downstream signaling components remain unidentified. Here, we report a mitogen-activated protein kinase (MAPK; or MPK) cascade that functions downstream of ER in regulating localized cell proliferation. Similar to an er mutant, loss of function of MPK3/MPK6 or their upstream MAPK kinases (MAPKKs; or MKKs), MKK4/MKK5, resulted in shortened pedicels and clustered inflorescences. Epistasis analysis demonstrated that the gain of function of MKK4 and MKK5 transgenes could rescue the loss-of-function er mutant phenotype at both morphological and cellular levels, suggesting that the MPK3/MPK6 cascade functions downstream of the ER receptor. Furthermore, YODA (YDA), a MAPKK kinase, was shown to be upstream of MKK4/MKK5 and downstream of ER in regulating inflorescence architecture based on both gain- and loss-of-function data. Taken together, these results suggest that the YDA-MKK4/MKK5-MPK3/MPK6 cascade functions downstream of the ER receptor in regulating localized cell proliferation, which further shapes the morphology of plant organs.
Analysis of tryptophan‐rich region in Clostridium septicum alpha‐toxin involved with binding to glycosylphosphatidylinositol‐anchored proteins
Authors: Mukamoto Masafumi , Kimura Ryota , Hang'ombe Mudenda B. , Kohda Tomoko , Kozaki Shunji
Published: December 2012

Clostridium septicum alpha‐toxin has a unique tryptophan‐rich region (302NGYSEWDWKWV312) that consists of 11 amino acid residues near the C‐terminus. Using mutant toxins, the contribution of individual amino acids in the tryptophan‐rich region to cytotoxicity and binding to glycosylphosphatidylinositol (GPI)‐anchored proteins was examined. For retention of maximum cytotoxic activity, W307 and W311 are essential residues and residue 309 has to be hydrophobic and possess an aromatic side chain, such as tryptophan or phenylalanine. When residue 308, which lies between tryptophans (W307 and W309) is changed from an acidic to a basic amino acid, the cytotoxic activity of the mutant is reduced to less than that of the wild type. It was shown by a toxin overlay assay that the cytotoxic activity of each mutant toxin correlates closely with affinity to GPI‐anchored proteins. These findings indicate that the WDW_W sequence in the tryptophan‐rich region plays an important role in the cytotoxic mechanism of alpha‐toxin, especially in the binding to GPI‐anchored proteins as cell receptors.
Aquatic ecosystem functions of an isolated floodplain and their implications for flood retention and management
Authors: Reckendorfer Walter , Funk Andrea , Gschöpf Christine , Hein Thomas , Schiemer Fritz
Published: December 2012

We used an isolated floodplain of the river Danube as a model system to gain an understanding on the functioning of retention areas to predict future developments and to sustain their ecological services.

We applied correlation analysis and spline regression models to assess the effects of geomorphology, hydraulics, and seasonality on sediment characteristics, suspended solids, hydrochemistry and primary producers.

The spatio‐temporal connection to the river is the primary factor influencing the hydrochemical characteristics and sediments. Allochthonous processes such as nutrient and sediment input during high waters dominate in connected parts of the floodplain, whereas autochthonous processes, for example, the release of phosphorus from the sediments and internally driven eutrophication, dominate in isolated parts. These conditions also affect the dominating primary producers, biodiversity, the degree of floodplain aggradation and thus the potential life span of aquatic habitats.

Measures to improve the functional basis for ecological services may use both allochthonous and autochthonous processes as a starting point, that is, minimizing sediment storage and nutrient input and improving the water balance to prolong the life span of isolated waters, and thus maximizing water body diversity and associated biodiversity.

Based on the results of our analysis and literature, eight alternative management measures have been evaluated. As a result, we propose a stepwise adaptive approach beginning with a controlled water supply with low sediments and nutrient loads. If these measures prove insufficient to sustain ecological functions and conservation value, more radical steps must be considered.

Synthesis and applications The increasing problems with catastrophic flooding have forced decision makers to seek basin‐wide solutions with focus on ‘more room for the river’ and the reintegration of former floodplains as retention basins. Such reintegrations also represent opportunities to improve the ecological conditions for nature development in addition to their principal function, that is, the storage of water during floods. The results of our study can serve as an effective tool to predict the effects of alternative management options and to establish and define the design criteria of water retention areas with regard to their ecological functions, life spans and biodiversity.
Exploring the mobility preferences and perceived difficulties in using transport and driving with a sample of healthy and outpatient older adults in Singapore
Authors: Krishnasamy Charmaine , Unsworth Carolyn A. , Howie Linsey
Published: December 2012

Background/aim

While activity engagement is important to older adults, limitations in ability can affect transport mode choice and subsequent activity participation. Therefore, this study aimed to explore the mobility preferences and difficulties in using public transport and driving with a sample of older adults in Singapore, with specific reference to accessing everyday activities.

Methods

One hundred and sixty‐two persons aged 50 years and over were recruited through a community event, and an outpatient occupational therapy department. They self‐completed structured questionnaire forms which were analysed using parametric and non‐parametric statistics, including t‐tests and ANOVAs.

Results

The majority of the participants were in the paid workforce and no significant differences were found between gender and the importance of transport for access to various activities, but a significant association was found for age and use of transport for going to work, F(5,101) = 3.07, P = 0.01. The majority of the drivers drove at least once a day, and 19% of them reported having noticed declines in their driving capabilities in the past four years, and indicated driving less often because of these concerns.

Conclusions

This study explored public transport and car use among a sample of older adults in Singapore to access desired activities. It identified difficulties with both public and private transportation use, such as difficulty maintaining balance/obtaining a seat, and concerns with decreased ability to respond quickly to traffic situations. This study has highlighted that transportation methods should be considered in occupational therapy practice with older adults.
Long‐ and short‐term effects of androgens in human umbilical artery smooth muscle
Authors: Saldanha Paulo A , Cairrão Elisa , Maia Cláudio J , Verde Ignacio
Published: December 2012

The aim of the present study was to determine the effects of androgens in the regulation of human umbilical artery (HUA) contractility. The short‐term effects of testosterone on the tone of the HUA were investigated, as were the long‐term effects of dihydrotestosterone (DHT) on the expression of some proteins involved in the contractile process.

Endothelium‐denuded HUA were treated for 24 h with DHT (2 μmol/L) or the vehicle control (ethanol) to analyse the genomic effects of androgens.

Twenty‐four hour treatment of HUA with DHT increased the mRNA expression of the β1‐subunit of the large‐conductance Ca2+‐activated (BKCa) channel and decreased expression of the α‐subunit of L‐type calcium channels.

In organ bath studies, testosterone (1–100 μmol/L) produced similar relaxant responses in DHT‐ and vehicle‐treated HUA rings precontracted with 5‐HT, histamine and KCl. However, the relaxation response obtained by the combined application of testosterone (100 μmol/L) and nifedipine (10 μmol/L) was significantly greater in DHT‐ compared with vehicle‐treated HUA.

The results indicate that the rapid vasorelaxant effects of testosterone that are dependent on both BKCa and voltage‐sensitive potassium (KV) channel activity in control arteries become dependent solely on KV channel activity in DHT‐treated HUA. Thus, the present study reveals the importance of the investigation of both the short‐ and long‐term effects of androgens in human arteries.
Non/infectious corporealities: tensions in the biomedical era of ‘HIV normalisation’
Authors: Persson Asha
Published: December 2012

In the contemporary HIV epidemic, antiretroviral treatments are increasingly considered so effective at viral suppression that they render people with HIV sexually non‐infectious. With its radical implications for global HIV prevention, this emerging paradigm is invested with the potential to turn the epidemic around and to ‘normalise’ one of the most feared infectious diseases in history, thus echoing wider trends of ‘biomedicalisation’. What remains unexamined is whether this paradigm shift will bring about a parallel shift in the embodied experiences of being HIV‐positive. This article explores the nascent trajectory from infectious to non‐infectious corporeality against the backdrop of the discursive history of HIV, with particular focus on the landmark Swiss Consensus Statement, and in the context of research with heterosexuals with HIV in Australia. In‐depth interviews revealed that HIV corporeality was not a stable, homogenised experience across participants and time, nor did it simply follow medical discourses. Instead, HIV corporeality emerged as a contingent set of tensions between conflicting discourses of infectiousness that were negotiated and made sense of within situated and embodied life histories. These findings pose challenges to the imperative of HIV normalisation and the related tendency in HIV prevention to universalise the notion of ‘infectiousness’.
Influence of fortification with sodium–calcium caseinate and whey protein concentrate on microbiological, textural and sensory properties of set‐type yoghurt
Authors: Ünal GÜlfem , Akalin A Sibel
Published: December 2012

The effect of fortification of yoghurt with sodium–calcium caseinate (SCC) and whey protein concentrate (WPC) on some properties of set‐type yoghurt were investigated. The addition of WPC enhanced the viability of Lactobacillus delbrueckii subsp. bulgaricus more than SCC. The highest firmness values were obtained from SCC‐fortified yoghurts, whereas yoghurts fortified with WPC had the highest water‐holding capacity during storage. The yoghurts fortified with 4% w/w SCC or 4% w/w WPC had the highest viscosity. Yoghurts fortified with 2% w/w SMP, SCC or WPC showed similar taste and overall acceptability scores; however, samples containing 4% w/w SCC or 4% w/w WPC had the lowest scores.
Consumer Valuation of Alternative Meat Origin Labels
Authors: Tonsor Glynn T. , Schroeder Ted C. , Lusk Jayson L.
Published: December 2012

Results from a split‐sample survey of the US population reveal consumers prefer meat products carrying origin information to unlabelled alternatives. Consumers are largely unaware of origin labelling laws and are indifferent to an important aspect of the implementation of current mandatory country of origin information rules in the US. In particular, consumers value meat products labelled ‘Product of North America’ approximately the same as ‘Product of United States’. Despite the similarity of these two labels, they have vastly different implications in terms of trade and segregation costs. Our results suggest that a transition from one label to the other is equally satisfying for the consumer while being less costly for processors and more acceptable to trade partners.
Identification of biomass utilizing bacteria in a carbon‐depleted glacier forefield soil by the use of 13C DNA stable isotope probing
Authors: Zumsteg Anita , Schmutz Stefan , Frey Beat
Published: December 2012

As Alpine glaciers are retreating rapidly, bare soils with low organic C and N contents are becoming exposed. Carbon availability is a key factor regulating microbial diversity and ecosystem functioning in these soils. The aim of this study was to investigate how bacterial activity, community structure and composition are influenced by organic carbon availability. Bare soils were supplied with 13C‐labelled fungal (Penicillium sp.) and green algal (Chlorella sp.) biomass and the CO2 evolution and its δ13C signature were monitored up to 60 days. These organisms have previously been isolated near the glacier terminus. DNA stable isotope probing followed by T‐RFLP profiling and sequencing of 16S rRNA genes was employed to identify consumers able to assimilate carbon from these biomass amendments. Higher respiration and higher bacterial activity indicated a more efficient utilization of algal cells than fungal cells. Flavobacterium sp. predominantly incorporated fungal‐derived C, whereas the algal‐derived C was mainly incorporated by Acidobacteria and Proteobacteria. This study emphasizes the important role of both fungal and algal biomass in increasing the carbon pool in recently deglaciated bare soils, as only 20% of the added C was respired as CO2, and the rest, we presume, remained in the soil.
Genome and proteome analysis of phage E3 infecting the soil‐borne actinomycete Rhodococcus equi
Authors: Salifu Samson P. , Valero‐Rello Ana , Campbell Samantha A. , Inglis Neil F. , Scortti Mariela , Foley Sophie , Vázquez‐Boland José A.
Published: December 2012

We report on the characterization and genomic analysis of bacteriophage E3 isolated from soil and propagating in Rhodococcus equi strains. Phage E3 has a circular genome of 142 563 bp and is the first Myoviridae reported for the genus Rhodococcus and for a non‐mycobacterial actinomycete. Phylogenetic analyses placed E3 in a distinct Myoviridae clade together with Mycobacterium phages Bxz1 and Myrna. The highly syntenic genomes of this myoviridal group comprise vertically evolving core phage modules flanked by hyperplastic regions specific to each phage and rich in horizontally acquired DNA. The hyperplastic regions contain numerous tRNA genes in the mycobacteriophages which are absent in E3, possibly reflecting bacterial host‐specific translation‐related phage fitness constraints associated with rate‐limiting tRNAs. A structural proteome analysis identified 28 E3 polypeptides, including 15 not previously known to be virion‐associated proteins. The E3 genome and comparative analysis provide insight into short‐term genome evolution and adaptive plasticity in tailed phages from the environmental microbiome.
Emotion‐Word Processing Difficulties in Abstinent Alcoholics With and Without Lifetime Externalizing Disorders
Authors: Endres Michael J. , Fein George
Published: December 2012

Background

Evidence suggests that abstinent alcoholics have difficulties processing a variety of emotion‐laden stimuli, and some of these difficulties may not fully resolve with long‐term abstinence. The current study examined whether emotion‐word processing difficulties were present in long‐term abstinent alcoholics (LTAA; 18+ months of sobriety) with and without a previously diagnosed externalizing (EXT; antisocial personality disorder and/or attention‐deficit/hyperactivity disorder diagnosis) disorder.

Methods

Subjects (N = 121) completed an affective go/no‐go (AGNG) task with positive, negative, and neutral emotion‐word stimuli, and a lexical decision‐making (LDM) task with nonemotion word and nonword stimuli. Nonsubstance abusing controls (NSAC;n = 38, 50.0% women, mean age = 48 ± 7.8),LTAAwithEXT(n = 32, 41% women, mean age = 47.1 ± 6.6), andLTAAwithoutEXT(n = 51, 47% women, mean age = 49.7 ± 6.5) were compared between signal discriminability (d′) and mean response times (RT) for correct responses (mcRT).

Results

In theLDMtask,LTAAhad lower (d′) values and slower mcRTthanNSAC. In theAGNGtask,LTAAandNSACdid not differ inAGNGtask mcRT.LTAAhad lower (d′) values thanNSAC, and this effect was partially associated with group differences inLDMtask (d′) values. InLTAA, lowerAGNG(d′) values also were associated with an earlier age of first drink, greater lifetime alcohol use, and a history ofEXTdisorder.

Conclusions

Our findings suggest that detecting the emotional content of words is impaired inLTAA, and this impairment is over and aboveLTAA's more general lexical processing difficulties. Results also suggest that specific emotion processing impairments inLTAAmay be exacerbated by greater lifetime alcohol use burden and other comorbidEXTdiagnoses.
Are Multiple Directorships Beneficial in East Asia?
Authors: Lee Kin‐Wai , Lee Cheng‐Few
Published: December 2012

We posit that the benefits and costs of multiple directorships are conditional on firm characteristics. We find firm valuation is positively associated with multiple directorships in (i) firms with high advising needs and (ii) firms with high external financing needs. These beneficial effects of multiple directorships are generally stronger in countries with weak shareholder rights and in firms that are widely held. However, when controlling shareholder hold high voting‐rights to cash‐flow rights, multiple directorships reduce firm valuation, especially in countries with weak shareholder rights and in closely held firms. As multiple directorships increases, cash holdings (capital expenditures) contribute less to shareholder value. The negative association between value of cash (capital expenditure) and busy boards is mitigated in firms with (i) high advising needs, (ii) high external financing needs and (iii) less entrenched ownership structures.