bluuebunny/crossref_metadata_2025 huggingface dataset:
The sucrose transporter SlSUT2 from tomato interacts with brassinosteroid functioning and affects arbuscular mycorrhiza formation
Authors: Bitterlich Michael , Krügel Undine , Boldt‐Burisch Katja , Franken Philipp , Kühn Christina
Published: March 2014

Mycorrhizal plants benefit from the fungal partners by getting better access to soil nutrients. In exchange, the plant supplies carbohydrates to the fungus. The additional carbohydrate demand in mycorrhizal plants was shown to be balanced partially by higher CO2 assimilation and increased C metabolism in shoots and roots. In order to test the role of sucrose transport for fungal development in arbuscular mycorrhizal (AM) tomato, transgenic plants with down‐regulated expression of three sucrose transporter genes were analysed. Plants that carried an antisense construct of SlSUT2 (SlSUT2as) repeatedly exhibited increased mycorrhizal colonization and the positive effect of plants to mycorrhiza was abolished. Grafting experiments between transgenic and wild‐type rootstocks and scions indicated that mainly the root‐specific function of SlSUT2 has an impact on colonization of tomato roots with the AM fungus. Localization of SISUT2 to the periarbuscular membrane indicates a role in back transport of sucrose from the periarbuscular matrix into the plant cell thereby affecting hyphal development. Screening of an expression library for SlSUT2‐interacting proteins revealed interactions with candidates involved in brassinosteroid (BR) signaling or biosynthesis. Interaction of these candidates with SlSUT2 was confirmed by bimolecular fluorescence complementation. Tomato mutants defective in BR biosynthesis were analysed with respect to mycorrhizal symbiosis and showed indeed decreased mycorrhization. This finding suggests that BRs affect mycorrhizal infection and colonization. If the inhibitory effect of SlSUT2 on mycorrhizal growth involves components of BR synthesis and of the BR signaling pathway is discussed.
Sexual dimorphism in autonomic changes and in the renin–angiotensin system in the hearts of mice subjected to thyroid hormone‐induced cardiac hypertrophy
Authors: Bezerra da Silveira Anderson Luiz , de Souza Miranda Manuela França , Mecawi André Souza , Melo Roberto Laureano , Marassi Michelle Porto , Matos da Silva Alba Cenélia , Antunes‐Rodrigues José , Olivares Emerson Lopes
Published: March 2014

New Findings

What is the central question of this study?

Based on the relevance of the renin–angiotensin system and the controversy regarding the role of the sympathetic nervous system in thyroid hormone‐related cardiac hypertrophy, the present study sought to establish whether there is a gender difference in activation of these systems and the degree of cardiac hypertrophy in mice.

What is the main finding and its importance?

Triiodothyronine increased sympathetic modulation and induced higher levels of cardiac angiotensin II in male than in female mice. This could explain the greater degree of cardiac hypertrophy induced by thyroid hormone found in the male mice.

Based on the relevance of the renin–angiotensin system and the ongoing controversy regarding the role of the sympathetic nervous system in thyroid hormone‐induced cardiac hypertrophy, the aim of the present study was to establish whether the putative difference in the degree of cardiac hypertrophy exhibited by males and females might be related to differences in the sympathetic–vagal balance and/or in the cardiac renin–angiotensin system in mice of different genders. Male and female mice (n = 117) were given 0.1 mg kg−1 of triiodothyronine or normal saline each day for 10 days consecutively. At the end of that period, study of the heart rate variability, spectral analysis and histopathological examination were performed to assess the sympathetic–vagal balance and the diameter of cardiomyocytes. The cardiac levels of angiotensin I and II were also measured. Treatment with triiodothyronine induced a greater degree of cardiac hypertrophy in male (∼73%) than in female mice (∼42%). This difference was attributed to greater modulation of the sympathetic nervous system and higher levels of angiotensin I and II in male than in female mice. Our data indicate that thyroid hormone‐induced cardiac hypertrophy was more intense in male mice due to the synergic effect of the sympathetic nervous system and the cardiac renin–angiotensin system.
Model Tests for a Floating Wind Turbine on Three Different Floaters
Authors: Koo Bonjun J. , Goupee Andrew J. , Kimball Richard W. , Lambrakos Kostas F.
Published: March 2014

Wind energy is a promising alternate energy resource. However, the on-land wind farms are limited by space, noise, and visual pollution and, therefore, many countries build wind farms near the shore. Until now, most offshore wind farms have been built in relatively shallow water (less than 30 m) with fixed tower type wind turbines. Recently, several countries have planned to move wind farms to deep water offshore locations to find stronger and steadier wind fields as compared to near shore locations. For the wind farms in deeper water, floating platforms have been proposed to support the wind turbine. The model tests described in this paper were performed at MARIN (maritime research institute netherlands) with a model setup corresponding to a 1:50 Froude scaling. The wind turbine was a scaled model of the national renewable energy lab (NREL) 5 MW horizontal axis reference wind turbine supported by three different generic floating platforms: a spar, a semisubmersible, and a tension-leg platform (TLP). The wave environment used in the tests is representative of the offshore in the state of Maine. In order to capture coupling between the floating platform and the wind turbine, the 1st bending mode of the turbine tower was also modeled. The main purpose of the model tests was to generate data on coupled motions and loads between the three floating platforms and the same wind turbine for the operational, design, and survival seas states. The data are to be used for the calibration and improvement of the existing design analysis and performance numerical codes. An additional objective of the model tests was to establish the advantages and disadvantages among the three floating platform concepts on the basis of the test data. The paper gives details of the scaled model wind turbine and floating platforms, the setup configurations, and the instrumentation to measure motions, accelerations, and loads along with the wind turbine rpm, torque, and thrust for the three floating wind turbines. The data and data analysis results are discussed in the work of Goupee et al. (2012, “Experimental Comparison of Three Floating Wind Turbine Concepts,” OMAE 2012-83645).
Aero-Hydro-Elastic Simulation of a Semi-Submersible Floating Wind Turbine
Authors: Philippe Maxime , Babarit Aurélien , Ferrant Pierre
Published: March 2014

This paper presents an aero-hydro-elastic model of a semi-submersible floating wind turbine. A specific attention is drawn to hydrodynamic modeling options and their effect on the dynamic response of the platform. The NREL 5 MW reference wind turbine mounted on the historical concept of semi-submersible platform Dutch tri-floater is considered. A specific hydrodynamic model of loads on a semi-submersible platform is used within the wind turbine design code FAST from NREL. This hydrodynamic model includes nonlinear hydrostatic and Froude-Krylov forces, diffraction/radiation forces obtained from linear potential theory, and Morison forces to take into account viscous effects on the braces and damping plates. The effect of the different hydrodynamic modeling options is investigated. As one could have expected, it is found that the effect of viscous drag on braces, and nonlinear Froude-Krylov loads, becomes larger with increasing wave height. Their effect remains of small order. Simulations also are run with directional waves, it is found that wave directionality induces larger transverse motions.
Techniques to Measure Solar Flux Density Distribution on Large-Scale Receivers
Authors: Röger Marc , Herrmann Patrik , Ulmer Steffen , Ebert Miriam , Prahl Christoph , Göhring Felix
Published: March 2014

Flux density measurement applied to central receiver systems delivers the spatial distribution of the concentrated solar radiation on the receiver aperture, measures receiver input power, and monitors and might control heliostat aimpoints. Commercial solar tower plants have much larger aperture surfaces than the receiver prototypes tested in earlier research and development (R&D) projects. Existing methods to measure the solar flux density in the receiver aperture face new challenges regarding the receiver size. Also, the requirements regarding costs, accuracy, spatial resolution, and measuring speed are different. This paper summarizes existent concepts, presents recent research results for techniques that can be applied to large-scale receivers and assesses them against a catalog of requirements. Direct and indirect moving bar techniques offer high measurement accuracy, but also have the disadvantage of large moving parts on a solar tower. In the case of external receivers, measuring directly on receiver surfaces avoids moving parts and allows continuous measurement but may be not as precise. This promising technique requires proper scientific evaluation due to specific reflectance properties of current receiver materials. Measurement-supported simulation techniques can also be applied to cavity receivers without installing moving parts. They have reasonable uncertainties under ideal conditions and require comparatively low effort.
Fast Pyrolysis of Biomass Pellets Using Concentrated Solar Radiation: A Numerical Study
Authors: Danaei Kenarsari Saeed , Zheng Yuan
Published: March 2014

Since the 1990s, mountain pine beetles have infested mature pine trees in the forests of western North America. Fast pyrolysis is an encouraging method to convert the beetle killed pine trees into bio-oils. In this study, an unsteady-state mathematical model is developed to simulate fast pyrolysis under concentrated solar radiation. Conservation equations of total mass, species, and energy, coupled with the chemical kinetics model, have been developed and solved to simulate fast pyrolysis of cylindrical biomass pellets in a quartz reactor exposed to various radiant heating fluxes. This study demonstrates the importance of the secondary reactions on fast pyrolysis products.
Effect of Load on Close-Coupled Post-Injection Efficacy for Soot Reduction in an Optical Heavy-Duty Diesel Research Engine
Authors: O’Connor Jacqueline , Musculus Mark
Published: March 2014

The use of close-coupled post injections is an in-cylinder soot-reduction technique that has much promise for high efficiency heavy-duty diesel engines. Close-coupled post injections, short injections of fuel that occur soon after the end of the main fuel injection, have been known to reduce engine-out soot at a wide range of engine operating conditions, including variations in injection timing, exhaust gas recirculation (EGR) level, load, boost, and speed. While many studies have investigated the performance of post injections, the details of the mechanism by which soot is reduced remains unclear. In this study, we have measured the efficacy of post injections over a range of load conditions, at constant speed, boost, and rail pressure, in a heavy-duty optically-accessible research diesel engine. Here, the base load is varied by changing the main-injection duration. Measurements of engine-out soot indicate that not only does the efficacy of a post injection decrease at higher engine loads, but that the range of post-injection durations over which soot reduction is achievable is limited at higher loads. Optical measurements, including the natural luminescence of soot and planar laser-induced incandescence of soot, provide information about the spatiotemporal development of in-cylinder soot through the cycle in cases with and without post-injections. The optical results indicate that the post injection behaves similarly at different loads, but that its relative efficacy decreases due to the increase in soot resulting from longer main-injection durations.
Optimal Decoupled Disturbance Observers for Dual-Input Single-Output Systems
Authors: Chen Xu , Tomizuka Masayoshi
Published: March 2014

The disturbance observer (DOB) has been a popular robust control approach for servo enhancement in single-input single-output systems. This paper presents a new extension of the DOB idea to dual- and multi-input single-output systems, and discusses an optimal filter design technique for the related loop-shaping. The proposed decoupled disturbance observer (DDOB) provides the flexibility to use the most suitable actuators for compensating disturbances with different spectral characteristics. Such a generalization is helpful, e.g., for modern dual-stage hard disk drives, where enhanced servo design is becoming more and more essential in the presence of vibration disturbances.
Effect of Nanotexturing on Increase in Elastohydrodynamic Lubrication Oil Film Thickness
Authors: Hirayama Tomoko , Ikeda Mitsutaka , Suzuki Toshiteru , Matsuoka Takashi , Sawada Hiroshi , Kawahara Kosuke
Published: March 2014

The effects of nanotexturing on oil film thickness and shape under pointcontact elasto-hydrodynamic lubrication (EHL) conditions were experimentally investigated. A disk-onball friction tester with an optical interferometer was used to measure oil film thickness and to observe the oil film shape. Periodic groove structures with a spiral, perpendicular, or parallel shape and with various groove depths and distances were formed by irradiation of a femtosecond laser onto the surface of steel balls. These nanotextured balls were tested under a load of 20 N and at rotational speeds from 1.0 to 3.0 m/s. Most of the balls with nanotexturing had a thicker oil film than those without texturing. The groove depth and angle were the key parameters determining the thickness of the oil film as they controlled the amount of side leakage of oil from the contact point. Optimization of these parameters resulted in an oil film that was almost twice as thick as that on the ball without texturing.
Thermocline Bed Properties for Deformation Analysis
Authors: Iverson Brian D. , Bauer Stephen J. , Flueckiger Scott M.
Published: March 2014

Thermocline tanks have been considered as an alternative to traditional two-tank molten salt thermal storage in concentrating solar power systems due to their potential for cost reduction. One concern for thermocline usage is thermal ratcheting caused by the internal rock bed deformation during cyclic operation and significant temperature fluctuations. Thermal ratcheting studies have been performed in the literature to identify the possibility of tank rupture. However, these studies numerically modeled the ratcheting behavior utilizing bed properties that have never been measured for the materials used in thermocline storage systems. This work presents triaxial test data quartzite and silica thermocline filler materials to better inform future investigations of thermal ratcheting. Molten salt is replaced with water as the interstitial fluid due to similarity in dimensionless numbers and to accommodate room temperature measurement. Material property data for cohesion, dilatancy angle, internal angle of friction, Young's modulus, Poisson's ratio, and bulk modulus are presented for 0.138–0.414 MPa confining pressure. The material properties are then compared to those assumed in the literature to comment on the potential impact of this property data relative to thermal ratcheting.
Engineering crystallinity of atomic layer deposited gate stacks containing ultrathin HfO2 and a Ti-based metal gate: Effects of postmetal gate anneal and integration schemes
Authors: Consiglio Steven , Tapily Kandabara , Clark Robert D. , Hasegawa Toshio , Amano Fumitaka , Leusink Gert J. , Jordan-Sweet Jean , Vasić Relja , Medikonda Manasa , Diebold Alain C.
Published: March 2014

In this study, the authors examined the effects of different annealing schemes on crystallinity in atomic layer deposition (ALD) grown Ti-containing metal gates and ultrathin ALD HfO2 high-k dielectric layers, and corresponding electrical results in metal oxide semiconductor capacitor (MOSCAP) devices. The authors investigated the effect of a postmetal deposition anneal (PMA) on the underlying HfO2, which was deposited using either a standard ALD process or a process which utilized a cyclical deposition and annealing scheme (termed DADA). The effect of the starting substrate surface, either chemically grown SiO2 or H-terminated Si, on HfO2 crystallinity was also studied. For 40 cycle ALD HfO2 (∼32 Å) with a TiN overlayer, a transition from an amorphous state to a cubic phase was observed with the application of a PMA treatment. Evidence of the orthorhombic phase of HfO2 with some level of texturing was observed for 40 cycle DADA processed films annealed with a TiN cap. Concomitantly a cubic (111) texture was observed for TiN deposited on DADA processed HfO2 and subjected to a PMA. Suppression of crystallinity for HfO2 deposited on H-terminated Si and annealed with a TiN layer was observed which illustrates the need for an adequate nucleation layer for uniform grain growth and increased atomic ordering. The authors also investigated metal gate stacks with a bilayer of TiN overlying Ti which showed reflections from both cubic TiN and hexagonal TiN0.3 in the as-deposited state and after annealing clear evidence of silicidation (TiSix) was observed. In MOSCAP structures with 40 cycle ALD HfO2 and a TiN overlayer subjected to a PMA, although the cubic phase of HfO2 was stabilized, there was no associated improvement in device scaling. This study highlights the importance of the initial crystalline state and nucleation of HfO2 as well as the thermal stability of the capping metal layer material when engineering dielectric layer crystallinity by means of a postmetal cap anneal. For ultrathin HfO2 integrated in advanced metal oxide semiconductor structures, the benefits of the stabilization of a higher-k phase through postmetal gate anneal may not be fully realized due to increased leakage along grain boundaries or decrease in effective k due to changes in the lower-k interfacial layer.
A C-Terminal Proline-Rich Sequence Simultaneously Broadens the Optimal Temperature and pH Ranges and Improves the Catalytic Efficiency of Glycosyl Hydrolase Family 10 Ruminal Xylanases
Authors: Li Zhongyuan , Xue Xianli , Zhao Heng , Yang Peilong , Luo Huiying , Zhao Junqi , Huang Huoqing , Yao Bin
Published: March 2014

Efficient degradation of plant polysaccharides in rumen requires xylanolytic enzymes with a high catalytic capacity. In this study, a full-length xylanase gene (
xynA
) was retrieved from the sheep rumen. The deduced XynA sequence contains a putative signal peptide, a catalytic motif of glycoside hydrolase family 10 (GH10), and an extra C-terminal proline-rich sequence without a homolog. To determine its function, both mature XynA and its C terminus-truncated mutant, XynA-Tr, were expressed in
Escherichia coli
. The C-terminal oligopeptide had significant effects on the function and structure of XynA. Compared with XynA-Tr, XynA exhibited improved specific activity (12-fold) and catalytic efficiency (14-fold), a higher temperature optimum (50°C versus 45°C), and broader ranges of temperature and pH optima (pH 5.0 to 7.5 and 40 to 60°C versus pH 5.5 to 6.5 and 40 to 50°C). Moreover, XynA released more xylose than XynA-Tr when using beech wood xylan and wheat arabinoxylan as the substrate. The underlying mechanisms responsible for these changes were analyzed by substrate binding assay, circular dichroism (CD) spectroscopy, isothermal titration calorimetry (ITC), and xylooligosaccharide hydrolysis. XynA had no ability to bind to any of the tested soluble and insoluble polysaccharides. However, it contained more α helices and had a greater affinity and catalytic efficiency toward xylooligosaccharides, which benefited complete substrate degradation. Similar results were obtained when the C-terminal sequence was fused to another GH10 xylanase from sheep rumen. This study reveals an engineering strategy to improve the catalytic performance of enzymes.
Diversity of Two-Domain Laccase-Like Multicopper Oxidase Genes in Streptomyces spp.: Identification of Genes Potentially Involved in Extracellular Activities and Lignocellulose Degradation during Composting of Agricultural Waste
Authors: Lu Lunhui , Zeng Guangming , Fan Changzheng , Zhang Jiachao , Chen Anwei , Chen Ming , Jiang Min , Yuan Yujie , Wu Haipeng , Lai Mingyong , He Yibin
Published: March 2014

Traditional three-domain fungal and bacterial laccases have been extensively studied for their significance in various biotechnological applications. Growing molecular evidence points to a wide occurrence of more recently recognized two-domain laccase-like multicopper oxidase (LMCO) genes in
Streptomyces
spp. However, the current knowledge about their ecological role and distribution in natural or artificial ecosystems is insufficient. The aim of this study was to investigate the diversity and composition of
Streptomyces
two-domain LMCO genes in agricultural waste composting, which will contribute to the understanding of the ecological function of
Streptomyces
two-domain LMCOs with potential extracellular activity and ligninolytic capacity. A new specific PCR primer pair was designed to target the two conserved copper binding regions of
Streptomyces
two-domain LMCO genes. The obtained sequences mainly clustered with
Streptomyces coelicolor
,
Streptomyces violaceusniger
, and
Streptomyces griseus
. Gene libraries retrieved from six composting samples revealed high diversity and a rapid succession of
Streptomyces
two-domain LMCO genes during composting. The obtained sequence types cluster in 8 distinct clades, most of which are homologous with
Streptomyces
two-domain LMCO genes, but the sequences of clades III and VIII do not match with any reference sequence of known streptomycetes. Both lignocellulose degradation rates and phenol oxidase activity at pH 8.0 in the composting process were found to be positively associated with the abundance of
Streptomyces
two-domain LMCO genes. These observations provide important clues that
Streptomyces
two-domain LMCOs are potentially involved in bacterial extracellular phenol oxidase activities and lignocellulose breakdown during agricultural waste composting.
Aerobic Granules: Microbial Landscape and Architecture, Stages, and Practical Implications
Authors: Gonzalez-Gil Graciela , Holliger Christof
Published: March 2014

For the successful application of aerobic granules in wastewater treatment, granules containing an appropriate microbial assembly able to remove contaminants should be retained and propagated within the reactor. To manipulate and/or optimize this process, a good understanding of the formation and dynamic architecture of the granules is desirable. Models of granules often assume a spherical shape with an outer layer and an inner core, but limited information is available regarding the extent of deviations from such assumptions. We report on new imaging approaches to gain detailed insights into the structural characteristics of aerobic granules. Our approach stained all components of the granule to obtain a high quality contrast in the images; hence limitations due to thresholding in the image analysis were overcome. A three-dimensional reconstruction of the granular structure was obtained that revealed the mesoscopic impression of the cavernlike interior of the structure, showing channels and dead-end paths in detail. In “old” granules, large cavities allowed for the irrigation and growth of dense microbial colonies along the path of the channels. Hence, in some areas, paradoxically higher biomass content was observed in the inner part of the granule compared to the outer part. Microbial clusters “rooting” from the interior of the mature granule structure indicate that granules mainly grow via biomass outgrowth and not by aggregation of small particles. We identify and discuss phenomena contributing to the life cycle of aerobic granules. With our approach, volumetric tetrahedral grids are generated that may be used to validate complex models of granule formation.
Deletion Mutant Library for Investigation of Functional Outputs of Cyclic Diguanylate Metabolism in Pseudomonas aeruginosa PA14
Authors: Ha Dae-Gon , Richman Megan E. , O'Toole George A.
Published: March 2014

We constructed a library of in-frame deletion mutants targeting each gene in
Pseudomonas aeruginosa
PA14 predicted to participate in cyclic di-GMP (c-di-GMP) metabolism (biosynthesis or degradation) to provide a toolkit to assist investigators studying c-di-GMP-mediated regulation by this microbe. We present phenotypic assessments of each mutant, including biofilm formation, exopolysaccharide (EPS) production, swimming motility, swarming motility, and twitch motility, as a means to initially characterize these mutants and to demonstrate the potential utility of this library.
Identification of
opsA
, a Gene Involved in Solute Stress Mitigation and Survival in Soil, in the Polycyclic Aromatic Hydrocarbon-Degrading Bacterium Novosphingobium sp. Strain LH128
Authors: Fida Tekle Tafese , Breugelmans Philip , Lavigne Rob , van der Meer Jan Roelof , De Mot René , Vaysse Pierre-Joseph , Springael Dirk
Published: March 2014

The aim of this study was to identify genes involved in solute and matric stress mitigation in the polycyclic aromatic hydrocarbon (PAH)-degrading
Novosphingobium
sp. strain LH128. The genes were identified using plasposon mutagenesis and by selection of mutants that showed impaired growth in a medium containing 450 mM NaCl as a solute stress or 10% (wt/vol) polyethylene glycol (PEG) 6000 as a matric stress. Eleven and 14 mutants showed growth impairment when exposed to solute and matric stresses, respectively. The disrupted sequences were mapped on a draft genome sequence of strain LH128, and the corresponding gene functions were predicted. None of them were shared between solute and matric stress-impacted mutants. One NaCl-affected mutant (i.e., NA7E1) with a disruption in a gene encoding a putative outer membrane protein (OpsA) was susceptible to lower NaCl concentrations than the other mutants. The growth of NA7E1 was impacted by other ions and nonionic solutes and by sodium dodecyl sulfate (SDS), suggesting that
opsA
is involved in osmotic stress mitigation and/or outer membrane stability in strain LH128. NA7E1 was also the only mutant that showed reduced growth and less-efficient phenanthrene degradation in soil compared to the wild type. Moreover, the survival of NA7E1 in soil decreased significantly when the moisture content was decreased but was unaffected when soluble solutes from sandy soil were removed by washing.
opsA
appears to be important for the survival of strain LH128 in soil, especially in the case of reduced moisture content, probably by mitigating the effects of solute stress and retaining membrane stability.
Biochemical and Kinetic Characterization of Xylulose 5-Phosphate/Fructose 6-Phosphate Phosphoketolase 2 (Xfp2) from Cryptococcus neoformans
Authors: Glenn Katie , Ingram-Smith Cheryl , Smith Kerry S.
Published: March 2014

Xylulose 5-phosphate/fructose 6-phosphate phosphoketolase (Xfp), previously thought to be present only in bacteria but recently found in fungi, catalyzes the formation of acetyl phosphate from xylulose 5-phosphate or fructose 6-phosphate. Here, we describe the first biochemical and kinetic characterization of a eukaryotic Xfp, from the opportunistic fungal pathogen
Cryptococcus neoformans
, which has two
XFP
genes (designated
XFP1
and
XFP2
). Our kinetic characterization of
C. neoformans
Xfp2 indicated the existence of both substrate cooperativity for all three substrates and allosteric regulation through the binding of effector molecules at sites separate from the active site. Prior to this study, Xfp enzymes from two bacterial genera had been characterized and were determined to follow Michaelis-Menten kinetics.
C. neoformans
Xfp2 is inhibited by ATP, phosphoenolpyruvate (PEP), and oxaloacetic acid (OAA) and activated by AMP. ATP is the strongest inhibitor, with a half-maximal inhibitory concentration (IC
50
) of 0.6 mM. PEP and OAA were found to share the same or have overlapping allosteric binding sites, while ATP binds at a separate site. AMP acts as a very potent activator; as little as 20 μM AMP is capable of increasing Xfp2 activity by 24.8% ± 1.0% (mean ± standard error of the mean), while 50 μM prevented inhibition caused by 0.6 mM ATP. AMP and PEP/OAA operated independently, with AMP activating Xfp2 and PEP/OAA inhibiting the activated enzyme. This study provides valuable insight into the metabolic role of Xfp within fungi, specifically the fungal pathogen
Cryptococcus neoformans
, and suggests that at least some Xfps display substrate cooperative binding and allosteric regulation.
UPC2
Is Universally Essential for Azole Antifungal Resistance in Candida albicans
Authors: Vasicek Erin M. , Berkow Elizabeth L. , Flowers Stephanie A. , Barker Katherine S. , Rogers P. David
Published: March 2014

In
Candida albicans
, the transcription factor Upc2 is central to the regulation of ergosterol biosynthesis.
UPC2
-activating mutations contribute to azole resistance, whereas disruption increases azole susceptibility. In the present study, we investigated the relationship of
UPC2
to fluconazole susceptibility, particularly in azole-resistant strains. In addition to the reduced fluconazole MIC previously observed with
UPC2
disruption, we observed a lower minimum fungicidal concentration (MFC) for a
upc2
Δ/Δ mutant than for its azole-susceptible parent, SC5314. Moreover, the
upc2
Δ/Δ mutant was unable to grow on a solid medium containing 10 μg/ml fluconazole and exhibited increased susceptibility and a clear zone of inhibition by Etest. Time-kill analysis showed higher fungistatic activity against the
upc2
Δ/Δ mutant than against SC5314.
UPC2
disruption in strains carrying specific resistance mutations also resulted in reduced MICs and MFCs.
UPC2
disruption in a highly azole resistant clinical isolate containing multiple resistance mechanisms likewise resulted in a reduced MIC and MFC. This mutant was unable to grow on a solid medium containing 10 μg/ml fluconazole and exhibited increased susceptibility and a clear zone of inhibition by Etest. Time-kill analysis showed increased fungistatic activity against the
upc2
Δ/Δ mutant in the resistant background. Microarray analysis showed attenuated induction by fluconazole of genes involved in sterol biosynthesis, iron transport, or iron homeostasis in the absence of
UPC2
. Taken together, these data demonstrate that the
UPC2
transcriptional network is universally essential for azole resistance in
C. albicans
and represents an attractive target for enhancing azole antifungal activity.
Spontaneous ectopic tubal pregnancy after laparoscopic tubal sterilisation by segmental isthmic partial salpingectomy
Authors: Drakopoulos P , Julen O , Petignat P , Dällenbach P
Published: March 2014

A 33-year-old woman with a history of tubal sterilisation, presented to our gynaecological emergency unit with acute abdominal pain and signs of peritonism. The first day of her last menstruation occurred 4 weeks and 4 days before. Urine pregnancy test was positive and transvaginal ultrasound revealed an empty uterus with a heterogeneous mass below the right ovary. We performed a laparoscopy, which confirmed a previous isthmic partial salpingectomy and the presence of an ectopic pregnancy in the right distal remnant tube. Total salpingectomy of the remnant parts of the tube was performed and the postoperative course was uneventful.
Synthesis and structures of 1,3-bis(organochalcogenyl) distannatrisilabicyclo[1.1.1]pentanes
Authors: Moos Eric , Augenstein Timo , Garnier Delphine , Breher Frank
Published: March 2014

The heteronuclear [1.1.1]propellane Sn2Si3Mes6 (1; Mes = 2,4,6-Me3C6H2) was reacted with the dichalcogenyl compounds PhE–EPh (E = S, Se, or Te) to furnish the 1,3-bis(organochalcogenyl) distannatrisilabicyclo[1.1.1]pentanes 3 (E = S), 4 (E = Se), and 5 (E = Te). The E–E bond addition reaction is reminiscent of the formation of FcS–Sn(SiMes2)3Sn–SFc (2; Fc = ferrocenyl) reported previously. Contrary to 2, for which it was shown that its formation can be enhanced by daylight, the analogous clusters 3–5 are very sensitive to light in solution. Solid samples are, however, stable for a prolonged period of time. All three compounds were characterized in detail, including X-ray structure analyses on single crystals of 3 and 5. The core structure connectivities of the clusters were fully confirmed by 119Sn, 77Se, and 125Te NMR spectroscopy, among others. In particular, the 117Sn–119Sn coupling constant between the formally nonbonded bridgehead tin atoms nicely correlates with the interbridgehead distance, i.e., a larger distance is associated with a smaller 117Sn–119Sn coupling constant, and vice versa. This coupling is mediated by so-called “back-lobe-to-back-lobe” interactions through cage. The detection of two different 77Se–119Sn and 125Te–119Sn couplings each (i.e., 1J and 2J) further supported these findings.
High-energy collisions inside black holes and their counterpart in flat spacetime
Authors: Zaslavskii O. B.
Published: March 2014

Two particles can collide inside a nonextremal black hole in such a way that the energy E c.m. in their center-of-mass frame becomes as large as one likes. We show that this effect can be understood with the help of a simple analogy with particle collisions in flat spacetime. As the two-dimensional part of near-horizon geometry inside a black hole is described by the flat Milne metric, the results have a general character. Full classification of scenarios with unbound E c.m. is suggested. Some scenarios of this kind require proximity of collision to the bifurcation point, but for some other ones this is not necessary.
Human Action Recognition Based on Normalized Interest Points and Super-Interest Points
Authors: Wang Yangyang , Li Yibo , Ji Xiaofei
Published: March 2014

Visual-based human action recognition is currently one of the most active research topics in computer vision. The feature representation directly has a crucial impact on the performance of the recognition. Feature representation based on bag-of-words is popular in current research, but the spatial and temporal relationship among these features is usually discarded. In order to solve this issue, a novel feature representation based on normalized interest points is proposed and utilized to recognize the human actions. The novel representation is called super-interest point. The novelty of the proposed feature is that the spatial-temporal correlation between the interest points and human body can be directly added to the representation without considering scale and location variance of the points by introducing normalized points clustering. The novelty concerns three tasks. First, to solve the diversity of human location and scale, interest points are normalized based on the normalization of the human region. Second, to obtain the spatial-temporal correlation among the interest points, the normalized points with similar spatial and temporal distance are constructed to a super-interest point by using three-dimensional clustering algorithm. Finally, by describing the appearance characteristic of the super-interest points and location relationship among the super-interest points, a new feature representation is gained. The proposed representation formation sets up the relationship among local features and human figure. Experiments on Weizmann, KTH, and UCF sports dataset demonstrate that the proposed feature is effective for human action recognition.
Scale invariance in fluvial barforms: implications for interpretation of fluvial systems in the rock record
Authors: Holzweber Barbara I. , Hartley Adrian J. , Weissmann Gary S.
Published: March 2014

Understanding the controls on the size and shape of sandstone bodies deposited by fluvial systems is important in the reconstruction of ancient fluvial deposits and construction of quantitative reservoir models. Measurements and analyses of sandbodies from remotely sensed imagery have allowed quantification of width and length ratios of barforms in modern fluvial systems. For bank-attached bars the width:length ratios range between 0.12 and 0.47 (arithmetic mean: 0.25), for lateral bars between 0.19 and 0.42 (arithmetic mean: 0.30), for mid-channel bars between 0.09 and 0.49 (arithmetic mean: 0.28), and for point bars between 0.14 and 0.50 (arithmetic mean: 0.30). The majority of width:length ratios for all bar types range between 0.15 and 0.35. Examination of other parameters such as basin type, planform geometry, apparent stream width, river length, gradient over the investigated area, aggradational or degradational system, tectonic setting and climate do not significantly affect the width:length ratio. Therefore, the bar planform shape, the width:length ratio, can be considered to be scale invariant. The recognition that bar planform shape in fluvial systems is scale invariant will be useful in the construction of subsurface three-dimensional models of fluvial deposits with variable dimensions.

Supplementary material:

Data tables with information obtained for all of the rivers studied are available at
http://www.geolsoc.org.uk/SUP18745
.
A novel integrated approach to estimating hydrocarbon saturation in the presence of pore-lining chlorites
Authors: Tudge Joanne , Lovell Mike , Davies Sarah , Millar Mike
Published: March 2014

Pore-lining chlorites are often associated with a low-resistivity contrast between corresponding reservoir units, making the identification and quantitation of hydrocarbon-bearing intervals difficult. In many low-resistivity situations, the traditional approach of using Archie’s equation to determine saturation from electrical resistivity fails, and modified Archie equations derived specifically for ‘shaly sands’ have been developed. In chlorite-bearing intervals, however, the effect of chlorite can be such that both Archie and the so-called shaly-sand models are inappropriate. Under these circumstances, calculating saturation from electrical resistivity can be circumvented by detailed analysis of the sedimentology and petrophysics, enabling the construction of a saturation height model based on core data. In this novel study we integrate a detailed core-based sedimentological facies scheme with wireline log data and petrophysical core data to demonstrate a clear link between chlorite occurrence, petrophysical characteristics and saturation height. Through this innovative approach, saturation is estimated without recourse to resistivity logs and improves hydrocarbon saturation estimates in chlorite-bearing reservoirs.
A survey on techniques for improving the energy efficiency of large-scale distributed systems
Authors: Orgerie Anne-Cecile , Assuncao Marcos Dias de , Lefevre Laurent
Published: March 2014

The great amounts of energy consumed by large-scale computing and network systems, such as data centers and supercomputers, have been a major source of concern in a society increasingly reliant on information technology. Trying to tackle this issue, the research community and industry have proposed myriad techniques to curb the energy consumed by IT systems. This article surveys techniques and solutions that aim to improve the energy efficiency of computing and network resources. It discusses methods to evaluate and model the energy consumed by these resources, and describes techniques that operate at a distributed system level, trying to improve aspects such as resource allocation, scheduling, and network traffic management. This work aims to review the state of the art on energy efficiency and to foster research on schemes to make network and computing resources more efficient.
Spaces, Trees, and Colors
Authors: Navarro Gonzalo
Published: March 2014

Document retrieval is one of the best-established information retrieval activities since the ’60s, pervading all search engines. Its aim is to obtain, from a collection of text documents, those most relevant to a pattern query. Current technology is mostly oriented to “natural language” text collections, where inverted indexes are the preferred solution. As successful as this paradigm has been, it fails to properly handle various East Asian languages and other scenarios where the “natural language” assumptions do not hold. Inthis survey, we cover the recent research in extending the document retrieval techniques to a broader class of sequence collections, which has applications in bioinformatics, data and web mining, chemoinformatics, software engineering, multimedia information retrieval, and many other fields. We focus on the algorithmic aspects of the techniques, uncovering a rich world of relations between document retrieval challenges and fundamental problems on trees, strings, range queries, discrete geometry, and other areas.
Design-for-testability for multi-cycle broadside tests by holding of state variables
Authors: Pomeranz Irith
Published: March 2014

This article describes a design-for-testability approach for increasing the transition fault coverage of multi-cycle broadside tests. Earlier methods addressed two-cycle tests. The importance of multi-cycle tests results from the ability to produce more compact test sets than possible with two-cycle tests, from the fact that when multi-cycle tests are applied at-speed, they can detect defects that are not detected by two-cycle tests and from their ability to avoid overtesting of delay faults. The approach described in this article is based on holding the values of selected state variables constant during the functional clock cycles of a multi-cycle broadside test. This allows new tests to be produced, which are different from broadside tests, without relying on nonfunctional toggling of state variables as in earlier methods for two-cycle tests. Experimental results show significant improvements in transition fault coverage using a fixed set of hold configurations for two types of multi-cycle broadside test sets: (1) test sets that are stored and applied from an external tester, and (2) functional broadside test sets that are generated using on-chip hardware.
Memory encryption
Authors: Henson Michael , Taylor Stephen
Published: March 2014

Memory encryption has yet to be used at the core of operating system designs to provide confidentiality of code and data. As a result, numerous vulnerabilities exist at every level of the software stack. Three general approaches have evolved to rectify this problem. The most popular approach is based on complex
hardware enhancements
; this allows all encryption and decryption to be conducted within a well-defined trusted boundary. Unfortunately, these designs have not been integrated within commodity processors and have primarily been explored through simulation with very few prototypes. An alternative approach has been to augment existing hardware with
operating system enhancements
for manipulating keys, providing improved trust. This approach has provided insights into the use of encryption but has involved unacceptable overheads and has not been adopted in commercial operating systems. Finally,
specialized industrial devices
have evolved, potentially adding coprocessors, to increase security of particular operations in specific operating environments. However, this approach lacks generality and has introduced unexpected vulnerabilities of its own. Recently, memory encryption primitives have been integrated within commodity processors such as the Intel i7, AMD bulldozer, and multiple ARM variants. This opens the door for new operating system designs that provide confidentiality across the entire software stack outside the CPU. To date, little practical experimentation has been conducted, and the improvements in security and associated performance degradation has yet to be quantified. This article surveys the current memory encryption literature from the viewpoint of these central issues.
Fostering Cooperation through Dynamic Coalition Formation and Partner Switching
Authors: Peleteiro Ana , Burguillo Juan C. , Arcos Josep Ll. , Rodriguez-Aguilar Juan A.
Published: March 2014

In this article we tackle the problem of maximizing cooperation among self-interested agents in a resource exchange environment. Our main concern is the design of mechanisms for maximizing cooperation among self-interested agents in a way that their profits increase by exchanging or trading with resources. Although dynamic coalition formation and partner switching (rewiring) have been shown to promote the emergence and maintenance of cooperation for self-interested agents, no prior work in the literature has investigated whether merging both mechanisms exhibits positive synergies that lead to increase cooperation even further. Therefore, we introduce and analyze a novel dynamic coalition formation mechanism, that uses partner switching, to help self-interested agents to increase their profits in a resource exchange environment. Our experiments show the effectiveness of our mechanism at increasing the agents’ profits, as well as the emergence of trading as the preferred behavior over different types of complex networks.
Security and privacy for augmented reality systems
Authors: Roesner Franziska , Kohno Tadayoshi , Molnar David
Published: March 2014

AR systems pose potential security concerns that should be addressed
before
the systems become widespread.
Unifying functional and object-oriented programming with Scala
Authors: Odersky Martin , Rompf Tiark
Published: March 2014

Scala unifies traditionally disparate programming-language philosophies to develop new components and component systems.
A Broadband Conformal Phased Array Antenna on Spherical Surface
Authors: Sun Dan , Shen Rong , Yan Xuequan
Published: March 2014

A Ku-band wideband conformal array antenna with13×19elements is presented in the paper. The array has a spherical structure, and its element is a proximity-coupled stacked patches antenna with a cavity-backed ground plane. The stacked patches and the cavity produce multiple coupled resonances, which enhance the bandwidth of the element extremely. A simulated model with the reasonable dimensions is framed with the coupling analyses, and the effective simulated results and good computing efficiency are obtained simultaneously. The measured results of the center embedded element in the whole array show a bandwidth exceeding 40%VSWR<2, which is close to the simulated matching performance.