bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics of multiple double layers in high pressure glow discharge in a simple torus
Authors: Kumar Paul Manash , Sharma P. K. , Thakur A. , Kulkarni S. V. , Bora D.
Published: June 2014

Parametric characterization of multiple double layers is done during high pressure glow discharge in a toroidal vessel of small aspect ratio. Although glow discharge (without magnetic field) is known to be independent of device geometry, but the toroidal boundary conditions are conducive to plasma growth and eventually the plasma occupy the toroidal volume partially. At higher anode potential, the visibly glowing spots on the body of spatially extended anode transform into multiple intensely luminous spherical plasma blob structures attached to the tip of the positive electrode. Dynamics of multiple double layers are observed in argon glow discharge plasma in presence of toroidal magnetic field. The radial profiles of plasma parameters measured at various toroidal locations show signatures of double layer formation in our system. Parametric dependence of double layer dynamics in presence of toroidal magnetic field is presented here.
Steady state characterization of bifacial solar cells at different configurations of air-based photovoltaic thermal solar panels
Authors: Ooshaksaraei P. , Aghili K. , Sopian K. , Zulkifli R. , Zaidi S. H.
Published: June 2014

This paper examines the first and second law efficiency of bifacial photovoltaic thermal (PVT) solar collectors. A mathematical model was developed to evaluate the system performance. Four air-based bifacial photovoltaic thermal panels were also designed based on the bifacial PV cell requirement. Most of the existing PVT designs contain an absorber plate, which in this research is replaced by a reflector to avoid blocking the rear aperture of bifacial cells. The following four air-based panel configurations were considered: single-path; double-path, parallel; double-path, counter flow; and double-path, returning flow. All four panel designs evaluated based on the first law and second law of thermodynamic, at steady state mode. Energy and exergy efficiencies of aforementioned designs strongly depend on packing factor and air mass flow rate. From an energy point of view (first law), the bifacial photovoltaic thermal panel with two parallel air streams exhibited the best efficiency (51%–67%) compared with that of the other three models. However, the exergy analysis indicated that a single air stream panel is preferable with 4.43%–10.15% exergy efficiency. The single-path panel design is the best option if electrical energy is the dominant desired output energy. But double-path parallel design is the best option if thermal energy is the dominant desired output energy.
Difference between compositional and grain size effect on the dielectric nonlinearity of Mn and V-doped BaTiO3 multilayer ceramic capacitors
Authors: Yoon Seok-Hyun , Park Jae-Sung , Kim Chang-Hoon , Kim Doo-Young
Published: June 2014

The difference between compositional and grain size effect on the dielectric nonlinearity was contrasted in Mn and V-doped BaTiO3 multilayer ceramic capacitors utilizing the first order reversal curve (FORC) distribution based on the Preisach model. The high field dielectric constants can be increased either by the adjustment of additive composition, that is, Ba concentration maintaining the same grain size, or by increasing its size. The former compositional effect caused an enhanced dielectric constant in both low and high field region, which can be associated with the increase in the saturation polarization, the reversible and the irreversible FORC distributions near zero bias. The latter grain growth effect, on the other hand, resulted in a decrease of the dielectric constants in the low field but a steep ac field dependence of them, which can be correlated with a decrease of the reversible FORC distribution and a significant increase of the irreversible FORC distribution near origin. These results show that the compositional effect is caused by the increase of the magnitude of the spontaneous polarization and the domain wall density, whereas the grain size effect is caused by the increase in the size of the domain and its wall, which increases the probability of domain pinning by weakly pinning centers but enables its long range motion beyond the threshold field.
Computational fluid dynamics analysis and experimental validation of improvement in overall energy efficiency of a solar photovoltaic panel by thermal energy recovery
Authors: Raval Hiren D. , Maiti Subarna , Mittal Ashish
Published: June 2014

The electrical efficiency of solar photovoltaic (PV) panel decreases with increase in its temperature because of its negative temperature co-efficient. This problem has been identified and attempts have been made to cool the photovoltaic panel by transferring heat by researchers the world over. The capitalization of the transferred heat for useful purpose is of prime importance since the conventional solar PV panel has the conversion efficiency of only 5%–17%. This means, about 83%–95% of incident energy is wasted and the proposition of recovering energy from solar PV panel can tap more thermal energy than electrical energy generated by PV panel itself. The present paper addresses this objective. The heat was transferred by direct contact heat exchange with flowing water from top of the panel. The direct contact heat exchange from top surface was found efficient in recovering energy as well improving the performance of PV panel. The refraction of light as it passes through the water layer straightens the incident radiation. The straightened radiation along with lower temperature of PV panel synergistically increases photovoltaic conversion efficiency. The computational fluid dynamics simulation of PV panel temperature closely resembles experimental data. There is a potential to recover energy at larger scale for large scale solar PV installations. Thus, the present paper proposes the win-win scenario of improved panel performance and maximum energy recovery.
Mechanical properties of hybrid organic-inorganic CH3NH3BX3 (B = Sn, Pb; X = Br, I) perovskites for solar cell absorbers
Authors: Feng Jing
Published: June 2014

The crystal structures, elastic and anisotropic properties of CH3NH3BX3 (B = Sn, Pb; X = Br, I) compounds as solar cell absorber layers are investigated by the first-principles calculations. The type and strength of chemical bond B-X are found to determine the elastic properties. B-X bonds and the organic cations are therefore crucial to the functionalities of such absorbers. The bulk, shear, Young's modulus ranges from 12 to 30 GPa, 3 to 12 GPa, and 15 to 37 GPa, respectively. Moreover, the interaction among organic and inorganic ions would have negligible effect for elastic properties. The B/G and Poisson's ratio show it would have a good ductile ability for extensive deformation as a flexible/stretchable layer on the polymer substrate. The main reason is attributed to the low shear modulus of such perovskites. The anisotropic indices AU, AB AG, A1, A2, and A3 show ABX3 perovskite have very strong anisotropy derived from the elastic constants, chemical bonds, and symmetry.
Top-gate zinc tin oxide thin-film transistors with high bias and environmental stress stability
Authors: Fakhri M. , Theisen M. , Behrendt A. , Görrn P. , Riedl T.
Published: June 2014

Top gated metal-oxide thin-film transistors (TFTs) provide two benefits compared to their conventional bottom-gate counterparts: (i) The gate dielectric may concomitantly serve as encapsulation layer for the TFT channel. (ii) Damage of the dielectric due to high-energetic particles during channel deposition can be avoided. In our work, the top-gate dielectric is prepared by ozone based atomic layer deposition at low temperatures. For ultra-low gas permeation rates, we introduce nano-laminates of Al2O3/ZrO2 as dielectrics. The resulting TFTs show a superior environmental stability even at elevated temperatures. Their outstanding stability vs. bias stress is benchmarked against bottom-gate devices with encapsulation.
Nanostructured double-layer FeO as nanotemplate for tuning adsorption of titanyl phthalocyanine molecules
Authors: Lu Shuangzan , Qin Zhihui , Cao Gengyu
Published: June 2014

The growth, structure of Pt(111) supported double-layer FeO and the adsorption of titanyl phthalocyanine (TiOPc) molecules with tunable site and orientation were presented. According to the atomic-resolution STM image, the structure was rationalized as (8√3 × 8√3) R30°/Pt(111) nanostructure constructed by Fe species coordinated with different number of oxygen on top of non-rotated (8 × 8) FeO /Pt(111) structure. Due to the modulation of the stacking of Fe atoms in the second layer relative to the O atoms in the second layer and the underlying layer, the interface and total dipole moment periodically vary within (8√3 × 8√3) R30°/Pt(111) structure. The resulted periodically distributed dipole-dipole interaction benefits the growth of TiOPc molecules with area-selective sites and molecular orientations. Thus, this study provides a reliable method to govern the adsorption process of the polar molecules for potential applications in future functional molecular devices.
Coexistence of superconductivity and charge-density-wave domain in 1T-FexTa1−xSSe
Authors: Liu Y. , Lu W. J. , Li L. J. , Ang R. , Sun Y. P.
Published: June 2014

A series of 1T-FexTa1−xSSe (0 ≤ x ≤ 0.1) single crystals were fabricated via the chemical-vapor-transport method and investigated by structure, transport, and magnetic measurements along with the density-functional-theory (DFT) calculations. The superconductivity (SC) in parent 1T-TaSSe can be gradually suppressed by Fe-substitution (x ≤ 0.03), accompanied by the disappearance of charge-density-wave (CDW). DFT calculations show that the Fe-substitution effectively inhibits the CDW superstructure and thereby the CDW domains are destroyed. With further increasing x (x > 0.03), the disorder-induced scattering increases, and the system enters into the possible Anderson localization state. Our results prove the SC develops in the CDW phase and coexists with the CDW domain in 1T-TaSSe system.
Yield strength dependence on strain rate of molybdenum-alloy nanofibers
Authors: Loya P. E. , Xia Y. Z. , Peng C. , Bei H. , Zhang P. , Zhang J. , George E. P. , Gao Y. F. , Lou J.
Published: June 2014

The yield strength dependence on strain rate was studied for molybdenum-alloy nanofibers with varying initial dislocation density at three different pre-strain levels. In-situ tensile experiments at three displacement rates were carried out in a scanning electron microscope. Yield strength and its scatter decreased as a function of the pre-strain level for different displacement rates. A statistical model was used to analyze the results, and a negative strain rate dependence was inferred from the yield experiments. This finding suggests the need for theoretical investigations since classical models such as dynamic strain aging may have limitations at such nanoscales.
Enhanced window breakdown dynamics in a nanosecond microwave tail pulse
Authors: Chang Chao , Zhu Meng , Verboncoeur John , Li Shuang , Xie Jialing , Yan Kai , Luo Tongding , Zhu Xiaoxin
Published: June 2014

The mechanisms of nanosecond microwave-driven discharges near a dielectric/vacuum interface were studied by measuring the time- and space-dependent optical emissions and pulse waveforms. The experimental observations indicate multipactor and plasma developing in a thin layer of several millimeters above interface. The emission brightness increases significantly after main pulse, but emission region widens little. The mechanisms are studied by analysis and simulation, revealing intense ionization concentrated in a desorbed high-pressure layer, leading to a bright light layer above surface; the lower-voltage tail after main pulse contributes to heat electron energy tails closer to excitation cross section peaks, resulting in brighter emission.
Polarization self-screening in [0001] oriented InGaN/GaN light-emitting diodes for improving the electron injection efficiency
Authors: Zhang Zi-Hui , Liu Wei , Ju Zhengang , Tiam Tan Swee , Ji Yun , Zhang Xueliang , Wang Liancheng , Kyaw Zabu , Wei Sun Xiao , Volkan Demir Hilmi
Published: June 2014

InGaN/GaN light-emitting diodes (LEDs) grown along the [0001] orientation inherit very strong polarization induced electric fields. This results in a reduced effective conduction band barrier height for the p-type AlGaN electron blocking layer (EBL) and makes the electron blocking effect relatively ineffective and the electron injection efficiency drops. Here, we show the concept of polarization self-screening for improving the electron injection efficiency. In this work, the proposed polarization self-screening effect was studied and proven through growing a p-type EBL with AlN composition partially graded along the [0001] orientation, which induces the bulk polarization charges. These bulk polarization charges are utilized to effectively self-screen the positive polarization induced interface charges located at the interface between the EBL and the last quantum barrier when designed properly. Using this approach, the electron leakage is suppressed and the LED performance is enhanced significantly.
Correlating defect induced ferromagnetism and gas sensing properties of undoped tin oxide sensors
Authors: Kamble Vinayak B. , Umarji Arun M.
Published: June 2014

A correlation between gas sensing properties and defect induced Room Temperature Ferromagnetism (RTFM) is demonstrated in non-stoichiometric SnO2 prepared by solution combustion method. The presence of oxygen vacancies (VO), confirmed by RTFM is identified as the primary factor for enhanced gas sensing effect. The as-prepared SnO2 shows high saturation magnetization of ∼0.018 emu/g as compared to ∼0.002 and ∼0.0005 emu/g in annealed samples and SnO2 prepared by precipitation respectively. The SnO2 prepared by precipitation which is an equilibrium method of synthesis shows lesser defects compared to the combustion product and hence exhibits lesser sensitivity in spite of smaller crystallite size. The study utilizes RTFM as a potential tool to characterize metal oxide gas sensors and recognizes the significance of oxygen vacancies in sensing mechanism over the microstructure.
Interplay between out-of-plane anisotropic L11-type CoPt and in-plane anisotropic NiFe layers in CoPt/NiFe exchange springs
Authors: Saravanan P. , Hsu Jen-Hwa , Tsai C. L. , Tsai C. Y. , Lin Y. H. , Kuo C. Y. , Wu J.-C. , Lee C.-M.
Published: June 2014

Films of L11-type CoPt/NiFe exchange springs were grown with different NiFe (Permalloy) layer thickness (tNiFe = 0–10 nm). X-ray diffraction analysis reveals that the characteristic peak position of NiFe(111) is not affected by the CoPt-layer—confirming the absence of any inter-diffusion between the CoPt and NiFe layers. Magnetic studies indicate that the magnetization orientation of NiFe layer can be tuned through varying tNiFe and the perpendicular magnetic anisotropy of L11-type CoPt/NiFe films cannot sustain for tNiFe larger than 3.0 nm due to the existence of exchange interaction at the interface of L11-CoPt and NiFe layers. Magnetic force microscopy analysis on the as-grown samples shows the changes in morphology from maze-like domains with good contrast to hazy domains when tNiFe ≥ 3.0 nm. The three-dimensional micro-magnetic simulation results demonstrate that the magnetization orientation in NiFe layer is not uniform, which continuously increases from the interface to the top of NiFe layer. Furthermore, the tilt angle of the topmost NiFe layers can be changed over a very wide range from a small number to about 75° by varying tNiFe from 1 to 10 nm. It is worth noting that there is an abrupt change in the magnetization direction at the interface, for all the tNiFe investigated. The results of present study demonstrate that the tunable tilted exchange springs can be realized with L11-type CoPt/NiFe bilayers for future applications in three-axis magnetic sensors or advanced spintronic devices demanding inclined magnetic anisotropy.
Charge carrier transport mechanisms in perovskite CdTiO3 fibers
Authors: Imran Z. , Rafiq M. A. , Hasan M. M.
Published: June 2014

Electrical transport properties of electrospun cadmium titanate (CdTiO3) fibers have been investigated using ac and dc measurements. Air annealing of as spun fibers at 1000 °C yielded the single phase perovskite fibers having diameter ∼600 nm - 800 nm. Both the ac and dc electrical measurements were carried out at temperatures from 200 K – 420 K. The complex impedance plane plots revealed a single semicircular arc which indicates the interfacial effect due to grain boundaries of fibers. The dielectric properties obey the Maxwell-Wagner theory of interfacial polarization. In dc transport study at low voltages, data show Ohmic like behavior followed by space charge limited current (SCLC) with traps at higher voltages at all temperatures (200 K – 420 K). Trap density in our fibers system is Nt = 6.27 × 1017 /cm3. Conduction mechanism in the sample is governed by 3-D variable range hopping (VRH) from 200 K – 300 K. The localized density of states were found to be N(EF) = 5.51 × 1021 eV−1 cm−3 at 2 V. Other VRH parameters such as hopping distance (Rhop) and hopping energy (Whop) were also calculated. In the high temperature range of 320 K – 420 K, conductivity follows the Arrhenius law. The activation energy found at 2 V is 0.10 eV. Temperature dependent and higher values of dielectric constant make the perovskite CdTiO3 fibers efficient material for capacitive energy storage devices.
Dynamical properties and their strain-dependence of ZnSe(ZnSe:N): Zinc-blende and wurtzite
Authors: Wang Dandan , Zhang Xiaojun , Li Binghui , Liu Lei , Shen D. Z.
Published: June 2014

The lattice dynamical properties of ZnSe and ZnSe with substitutional N incorporation(ZnSe:N) are investigated in both the zinc-blend(ZB) and wurtzite(WZ) structures using first-principles calculations. The optical phonon modes of ZB-ZnSe at the Γ-point locate at 250 cm−1 for LO and 213 cm−1 for TO. The characteristic E2 phonon modes at about 50 cm−1 and the E1 and another E2 phonon modes around 200 cm−1 of WZ-ZnSe are suggested to be the fingerprint for distinguishing the two polytypes of ZnSe. For substitutional N incorporated ZnSe, the N incorporation introduces three new high energy modes above 500 cm−1, and the splitting of them is much larger in the WZ phase than that in ZB phase. The strain dependence of phonon frequency which could be useful for corresponding spectroscopic strain characterization are also studied. The simple linear dependence is determined for ZB-ZnSe, while the situation for WZ-ZnSe looks more complicated.
Interactions of main chain in folding and self assembly of unfolded protein structure: Enquiries with a serine solubilized nonapeptide
Authors: Srivastava Kinshuk Raj , Durani Susheel
Published: June 2014

Interactions of the protein main chain are probed for their role in folding and self-assembly. The interactions are assessed with serine nonapeptide Ac-(Ser-Ala)4-Ser-NH2 in poly-L and alternating-L,D structure variations. Being a neutral molecule, Serine nonapeptide has been found to display not only folding-unfolding equilibrium, but also association-dissociation equilibrium as a function of solvent and concentration. Thus scrutiny of intra- and inter-molecular interactions have been undertaken in water, methanol, and DMSO solvents. In water, poly-L peptide displays a PPII-helix conformation which unfolds to extended β-conformation with increase of temperature, apparently in a two-state equilibrium. Poly-L peptide at high concentration and on transfer to the low polarity solvent, methanol, displays ordering as a β-hairpin. This implies folding of the peptide by self assembly. Self assembly and ordering possibly as double-stranded β-helix is also evidence for alternating-L,D peptide. Both isomers were observed to be unfolded in high polarity solvent DMSO. Dynamic light scattering suggests that assembly in both isomers may involve large size aggregates. The results have established that folding and self-assembly can be coupled equilibria dependent upon solute structure, concentration, and solvent. The interactions of the protein main chain involved in folding and self assembly of unfolded structure are illuminated and have been discussed.
Total absorption by degenerate critical coupling
Authors: Piper Jessica R. , Liu Victor , Fan Shanhui
Published: June 2014

We consider a mirror-symmetric resonator with two ports. We show that, when excited from a single port, complete absorption can be achieved through critical coupling to degenerate resonances with opposite symmetry. Moreover, any time two resonances with opposite symmetry are degenerate in frequency and absorption is always significantly enhanced. In contrast, when two resonances with the same symmetry are nearly degenerate, there is no absorption enhancement. We numerically demonstrate these effects using a graphene monolayer on top of a photonic crystal slab, illuminated from a single side in the near-infrared.
Parameters influencing the deposition of methylammonium lead halide iodide in hole conductor free perovskite-based solar cells
Authors: Cohen Bat-El , Gamliel Shany , Etgar Lioz
Published: June 2014

Perovskite is a promising light harvester for use in photovoltaic solar cells. In recent years, the power conversion efficiency of perovskite solar cells has been dramatically increased, making them a competitive source of renewable energy. An important parameter when designing high efficiency perovskite-based solar cells is the perovskite deposition, which must be performed to create complete coverage and optimal film thickness. This paper describes an in-depth study on two-step deposition, separating the perovskite deposition into two precursors. The effects of spin velocity, annealing temperature, dipping time, and methylammonium iodide concentration on the photovoltaic performance are studied. Observations include that current density is affected by changing the spin velocity, while the fill factor changes mainly due to the dipping time and methylammonium iodide concentration. Interestingly, the open circuit voltage is almost unaffected by these parameters. Hole conductor free perovskite solar cells are used in this work, in order to minimize other possible effects. This study provides better understanding and control over the perovskite deposition through highly efficient, low-cost perovskite-based solar cells.
Vacuum gate dielectric gate-all-around nanowire for hot carrier injection and bias temperature instability free transistor
Authors: Han Jin-Woo , Moon Dong-Il , Sub Oh Jae , Choi Yang-Kyu , Meyyappan M.
Published: June 2014

A gate-all-around (GAA) field effect transistor with vacuum gate dielectric is presented as a structure free from hot-carrier injection and bias temperature instability. A conventional GAA fabrication process is used along with selective removal of the sacrificial gate oxide as an extra process step. The lowered dielectric constant in vacuum gate dielectric can be compensated by the nature of the nanowire and physical oxide thickness reduction. As the nanowire channel is fully surrounded by empty space, reliability issues relevant to the gate dielectric can be completely cleared.
Scenario Praxis for Systemic Governance: A Critical Framework
Authors: Ison Ray , Grant Andrea , Bawden Richard
Published: June 2014

Scenario praxis, critically explored as the theory-informed practice of scenarioing, is proposed as a modality for institutionalising knowing within a systemic governance framework. Framing and institutional considerations associated with a constructivist inquiry-based learning approach that might open capacity for innovation in future scenarioing praxis are outlined to complement and counterbalance positivistoriented evidence-based approaches. Drawing on espoused theoretical and epistemological commitments, background literature, researcher experience, and our framing choices, we describe a heuristic device for use ex post to critically examine accounts of past scenario development, or ex ante to generate scenarios. The heuristic and its process of generation are designed for use in context-sensitive ways suited to the systemic governance of climate change adaptation and similar situations that can be framed as ‘wicked’ or uncertain.
The Problem of Fit: Scenario Planning and Climate Change Adaptation in the Public Sector
Authors: Rickards Lauren , Wiseman John , Edwards Taegen , Biggs Che
Published: June 2014

Adapting to climate change is a new responsibility for state and local government. Yet there is little clarity about what is involved, beyond an expectation of acting in a rational, informed manner. This paper presents a study from Victoria, Australia into public servants' perceptions and experiences of using scenario techniques for adaptation. It suggests that while scenario development is often positive for those involved, utilising scenarios to directly ‘inform’ adaptation decision making is more difficult. It seems that scenarios are a valuable but awkward form of evidence in the contemporary environment of evidence-based adaptation, introducing new substantive knowledge in an unfamiliar form, easily dismissed on credibility, legitimacy, and salience grounds. While scenario thinking is a good fit with climate change adaptation, it clashes with the predictive paradigm underlying the evidence-based decision-making model. This suggests that, for adaptation to better fit the institutional environment, alterations to the latter are needed.
A Financial Appraisal of Business Improvement Districts in the UK
Authors: Hemphill Lesley , Berry Jim , McGreal Stanley
Published: June 2014

Urban regeneration has increasingly emphasised long-term policy objectives and public—private partnership arrangements where risk and profits are more equitably distributed between the parties. Similarly, successive governments have endorsed area-based regeneration vehicles with increasing importance placed on enterprise zones, business improvement districts (BIDs), tax incremental finance, and other local asset backed vehicles. Each regeneration vehicle necessitates a clear policy direction and performance measurement of its policy outputs to ensure that funding is targeted at initiatives delivering sustainability impacts. This paper presents a ‘market’ and ‘nonmarket’ appraisal of the financial impact of BIDs as an area-based regeneration vehicle. It utilises data from a UK-wide survey to demonstrate the potential of BIDs in generating direct income and indirect investment and how the output capacity of the BID model increases over time. The paper concludes that BIDs have significant leverage potential whilst acting as a key conduit for coordinating wider area-based regeneration.
Evidence, Uncertainty, and Wicked Problems in Climate Change Decision Making in Australia
Authors: Head Brian W
Published: June 2014

Policy makers have had great difficulty in understanding and responding effectively to complex or ‘wicked’ problems. Contentious policy initiatives are hard to implement when knowledge bases are divergent and incomplete, when short-term interests conflict with long-term benefits, and when problems are construed or framed in very different ways. These features of wicked problems have been central in Australian debates about initiatives to reduce greenhouse gas emissions and to address the likely impacts of climate change. Given the closely interconnected nature of social, technical, legal—political, economic, and natural-resource issues, the political challenges of managing adaptive change are numerous. A strategic adaptation framework is necessary to complement ongoing mitigation efforts directed at greenhouse gas reduction. Strategic innovation requires pluralistic and adaptive processes, such as multistakeholder forums, consideration of scenario analyses, and the use of boundary organizations. In light of the highly contested nature of the issues, the multiple bases of knowledge and interests, and the provisional nature of adaptation choices, there are major policy governance challenges facing the Australian government and stakeholders in grappling with climate adaptation.
Contestation and Bracketing: The Relation between Public Space and the Public Sphere
Authors: Cassegård Carl
Published: June 2014

In this paper I seek to clarify the relation between the notions of public space and the public sphere by distinguishing between two dimensions of publicness—contestation and bracketing—in the classical notion of the public sphere as developed by Jürgen Habermas and Hannah Arendt. By clarifying this relation I aim to bring out how public space can be seen as the site of political practices distinct from those usually associated with the public sphere. That in turn will facilitate an understanding of why the idea of public space has been resorted to by activists and scholars to overcome limitations of the public sphere. On the basis of the two dimensions, I propose a distinction between two notions of public space, one centred on contestation and another on bracketing. I argue that both conceptions help articulate political practices that go beyond what is customarily allowed for in the deliberations of the public sphere: On the one hand, practices that visibilize dissent and expose inequalities and, on the other hand, practices that construct alternative arenas where marginal or subordinate people's self-confidence as political actors can be strengthened.
Antibiotics and oxygen availability affect the short-term storage of spermatozoa from the critically endangered booroolong frog, Litoria booroolongensis
Authors: Silla Aimee J. , Keogh Leesa M. , Byrne Phillip G.
Published: June 2014

Sperm-storage technologies aim to extend sperm longevity and increase the time available to achieve artificial fertilisation. The aim of the present study was to quantify the effects of antibiotic supplementation (4 mg mL–1 gentamicin) and altered gaseous storage environment (100%, 20% and 0% O2) on sperm longevity in the critically endangered booroolong frog, Litoria booroolongensis. A split-sample experimental design was adopted, whereby each sperm suspension (n = 10) was evenly divided among six experimental treatments (100% O2 with antibiotic, 20% O2 with antibiotic, 0% O2 with antibiotic, 100% O2 without antibiotic, 20% O2 without antibiotic, 0% O2 without antibiotic). Sperm suspensions were refrigerated at 5°C for the duration of the 21-day storage period. Percentage sperm motility and sperm velocity were quantified every 3 days using a computer-assisted sperm analysis system. Treatments aerated with either 100% or 20% oxygen, without the addition of the antibiotic gentamicin, consistently exhibited the highest percentage sperm motility. On Day 21 of storage, sperm suspensions in these two treatments (100% O2 without antibiotic, 20% O2 without antibiotic) maintained 61.3% and 52.0% sperm motility, respectively, whereas all remaining experimental treatments exhibited <30% sperm motility. Sperm velocity did not differ significantly among storage treatments, at any of the sampling periods, with the exception of day 21. Overall, the results from this study indicate that increased oxygen availability is beneficial to sperm longevity, but that gentamicin inhibits sperm motility in L. booroolongensis.
Virtual herding for flexible livestock management – a review
Authors: Anderson Dean M. , Estell Rick E. , Holechek Jerry L. , Ivey Shanna , Smith Geoffrey B.
Published: June 2014

Free-ranging livestock play a pivotal role globally in the conversion of plant tissue into products and services that support man’s many and changing lifestyles. With domestication came the task of providing livestock with an adequate plane of nutrition while simultaneously managing vegetation for sustainable production. Attempting to meld these two seemingly opposing management goals continues to be a major focus of rangeland research. Demand for multiple goods and services from rangelands today requires that livestock production make the smallest possible ‘negative hoof-print’. Advancements in global navigation satellite system, geographic information systems, and electronic/computing technologies, coupled with improved understanding of animal behaviour, positions virtual fencing (VF) as an increasingly attractive option for managing free-ranging livestock. VF offers an alternative to conventional fencing by replacing physical barriers with sensory cues to control an animal’s forward movement. Currently, audio and electrical stimulation are the cues employed. When VF becomes a commercial reality, manual labour will be replaced in large part with cognitive labour for real-time prescription-based livestock distribution management that is robust, accurate, precise and flexible. The goal is to manage rangeland ecosystems optimally for soils, plants, herbivores in addition to the plant and animal’s microflora. However, maximising the benefits of VF will require a paradigm shift in management by using VF as a ‘virtual herder’ rather than simply as a tool to manage livestock within static physical barriers.
Proximate causes and possible adaptive functions of mast seeding and barren flower shows in spinifex grasses (Triodia spp.) in arid regions of Australia
Authors: Wright Boyd R. , Zuur Alain F. , Chan Gary C. K.
Published: June 2014

Mast seeding, the intermittent production of large synchronised seed crops among plant populations, is a phenomenon that occurs at exceptionally long intervals in spinifex grasses (Triodia spp.) from arid regions of Australia. This is despite the reliance of these fire-sensitive plants on seeds for post-fire regeneration, and that spinifex grasslands rate among Australia’s most flammable ecosystems. The proximate causes and possible adaptive functions of masting in seven species of spinifex from arid regions within the 350-mm rainfall isohyet were investigated. Specifically, the seed set percentages of 79 specimens collected between 1947 and 2012 were related to the following environmental covariates: antecedent rainfall over 6, 12 and 36 months, relative humidity, and the number of days above 40°C and below 0°C during anthesis. Given the potential importance of seeding events for post-fire regeneration, it was also investigated whether masting in Triodia could represent a fire-related form of environmentally predictive masting, by testing whether high-yield years corresponded to years of increased fire occurrence. Examination of the dataset showed that 43% of specimens contained completely aborted inflorescences (0% seed fill), while seed set ranged from 2 to 69% in the remaining specimens. High levels of insect activity were also found, with 42% of specimens showing evidence of insect occupation. Statistical analyses showed that the main environmental driver of seed set was high precipitation over the previous 12 months, and that high-yield years were strongly related to years of increased fire likelihood. The number of days over 40°C was a weakly significant driver of yield, while the remaining covariates were not significant. It is hypothesised that intermittent reproduction by Triodia is a fire-related form of environmentally predictive masting, which maximises chances of post-fire regeneration by satiating seed predators during flammable periods (i.e. after heavy rain years). Furthermore, it is suggested that non-viable flower crops after initial low rainfalls may have an adaptive function, by diluting pre-dispersal seed predator densities with ‘decoy’ ovules that do not mature and lead to the starvation of developing larvae.
The sustainable development of grassland-livestock systems on the Tibetan plateau: problems, strategies and prospects
Authors: Shang Z. H. , Gibb M. J. , Leiber F. , Ismail M. , Ding L. M. , Guo X. S. , Long R. J.
Published: June 2014

The Tibetan plateau is the source of most of the major rivers of Asia and has a huge impact on the livelihoods of the population, who have for centuries engaged in traditional herding practices. Sustainable management of the plateau is of critical importance not only for maintaining livelihoods but also because of its vital ecological function. The major problem of sustainable development in these grassland-livestock systems is the conflict between forage and livestock production. Despite considerable investment of manpower, material resources and capital over many years, attempts to resolve the problem have not been successful. The magnitude of conflict between forage and livestock is addressed by presenting 19 resolution strategies based on numerous research data. Each of these strategies is evaluated in terms of how it can be implemented, its potential benefits for livestock production, current progress and the requirement for further research. The 19 strategies have been divided into four topic categories, namely; grassland-forage, livestock, economy and market, society-culture, which cover the basic elements of sustainable development in this pastoral region. It is argued that improved planning and implementation of the proposed strategies must be based on the background investigation of natural and social status of the pastoral region. Particular attention needs to be given to genetic resources and technology in order to ensure the successful implementation of these proposals. In addition to expanding the use of 18 currently practiced strategies, the authors propose a further novel strategy of replacing the current intensive form of ecological migration with a model incorporating two semi-permanent settlements. The objective of this novel strategy is to retain the nomadic element of pastoral husbandry while increasing the temporal and spatial scale of rotational stocking to reduce pasture degradation on the Tibetan plateau. It is argued that these proposals should be urgently incorporated into two national plans for the pastoral livestock industry, and the construction of an ecologically safe shelter zone on the Tibetan plateau, while ensuring a sustainable livelihood of its pastoral residents. Ensuring a successful implementation of these strategies in resolving the conflict between grassland and livestock, and promoting sustainable development on the Tibetan plateau, requires willing support at the level of national investment and policy commitment and from the herdsmen.
Adherence-enhancing interventions for active antiretroviral therapy in sub-Saharan Africa: a systematic review and meta-analysis
Authors: Mathes Tim , Antoine Sunya-Lee , Pieper Dawid
Published: June 2014

Background In sub-Saharan Africa, an estimated 23% of HIV-infected patients are nonadherent. The objective was to evaluate the effectiveness of adherence-enhancing interventions for active antiretroviral therapy (ART) in HIV-infected patients in sub-Saharan Africa. Methods: A systematic literature search was performed with the following inclusion criteria: adult HIV patients treated with ART, an intervention to enhance patient adherence, adherence rate as an outcome, a clinical or patient outcome, a randomised controlled trial and conducted in sub-Saharan Africa. Studies were selected by two reviewers independently. Data on patient characteristics, interventions, adherence definition and measures, and results were extracted. The risk of bias was evaluated by two reviewers independently. A meta-analysis was performed where appropriate. All discrepancies were discussed until consensus. Results: Six trials fulfilled all inclusion criteria. One showed statistically significant results in favour of the intervention for adherence rate and clinical outcome. The other studies showed either no significant results for any outcome or heterogeneous results depending on the outcome type. Aside from the clinical outcomes in one study, all outcomes showed a tendency in favour of the intervention groups. In the meta-analysis short message service (SMS) interventions showed a statistically significant effect on adherence (risk difference = –0.10; 95% confidence interval (CI): –0.17 to –0.03) and modified directly observed therapy (DOT) showed a significant effect on mortality (relative risk = 0.75; 95% CI: 0.44–1.26). Conclusion: The adherence-enhancing interventions (DOT, SMS interventions, counselling plus an alarm device) increased adherence only slightly, possibly because the high baseline adherence causes a ceiling effect.
Gene-targeted microfluidic cultivation validated by isolation of a gut bacterium listed in Human Microbiome Project's Most Wanted taxa
Authors: Ma Liang , Kim Jungwoo , Hatzenpichler Roland , Karymov Mikhail A. , Hubert Nathaniel , Hanan Ira M. , Chang Eugene B. , Ismagilov Rustem F.
Published: June 2014

Significance

Obtaining cultures of microbes is essential for developing knowledge of bacterial genetics and physiology, but many microbes with potential biomedical significance identified from metagenomic studies have not yet been cultured due to the difficulty of identifying growth conditions, isolation, and characterization. We developed a microfluidics-based, genetically targeted approach to address these challenges. This approach corrects sampling bias from differential bacterial growth kinetics, enables the use of growth stimulants available only in small quantities, and allows targeted isolation and cultivation of a previously uncultured microbe from the human cecum that belongs to the high-priority group of the Human Microbiome Project’s “Most Wanted” list. This workflow could be leveraged to isolate novel microbes and focus cultivation efforts on biomedically important targets.
Oligotyping analysis of the human oral microbiome
Authors: Eren A. Murat , Borisy Gary G. , Huse Susan M. , Mark Welch Jessica L.
Published: June 2014

Significance

The human body, including the mouth, is home to a diverse assemblage of microbial organisms. Although high-throughput sequencing of 16S rRNA genes provides enormous amounts of census data, accurate identification of taxa in these large datasets remains problematic because widely used computational approaches do not resolve closely related but distinct organisms. We used a computational approach that relies on information theory to reanalyze the human oral microbiome. This analysis revealed organisms differing by as little as a single rRNA nucleotide, with dramatically different distributions across habitats or individuals. Our information theory-based approach in combination with habitat analysis demonstrates the potential to deconstruct entire microbiomes, detect previously unrecognized diversity, and provide deep insight into microbial communities in health and disease.
Construction of novel chimeric proteins through the truncation of SEC2 and Sak from Staphylococcus aureus
Authors: Hui Jing , Yu Xiao-jie , Cui Xiao-jin , Mu Teng , Lin Jia-shuai , Ni Pei , Li Hui , You Song , Hu Feng-qing
Published: June 2014

It is an usual clinical phenomenon that cancer patients are prone to thrombosis. Until now, there have been no efficient methods or appropriate drugs to prevent and cure tumor thrombus. Therefore, the construction of a bifunctional chimeric protein for the treatment of cancer, complicated with thrombosis, is of great significance. Utilizing the superantigenic activity of staphylococcal enterotoxin C2 (SEC2) and the thrombolytic activity of staphylokinase (Sak), Sak-linker-SEC2 and SEC2-linker-Sak were constructed which had good anti-tumor and thrombolytic activities at the same time. Due to the intrinsic emetic activity of SEC2 and high molecular weight (MW) of chimeric proteins (44 kDa), their clinical applications will be restricted. In this study, novel chimeric proteins including ΔSEC2–ΔSak and ΔSak–ΔSEC2 were constructed through the truncation of SEC2 and Sak without 9-Ala linker and His-tag. Compared with the former, both the truncated proteins preserved nearly the same anti-tumor and thrombolytic activities. In addition, their MWs were only 29 kDa and their immunoreactivities were slightly lower than that of Sak-linker-SEC2 and SEC2-linker-Sak, respectively. Therefore, the novel chimeric proteins possessed merits and characteristics, such as low MS, low immunogenicity, and difunctionality which the former had not. It will be of great interest if the above-mentioned proteins can be used to cure Trousseau syndrome in clinic.
Quantitative proteomics study of protective effects of grape seed procyanidin B2 on diabetic cardiomyopathy in db/db mice
Authors: Luan Si-si , Yu Fei , Li Bao-ying , Qin Rui-jie , Li Xiao-li , Cai Qian , Yin Wen-bin , Cheng Mei , Gao Hai-qing
Published: June 2014

Diabetic cardiomyopathy is one of the major complications of diabetes mellitus. Oxidative stress appears to play a substantial role in cardiomyopathy. Grape seed procyanidin B2 (GSPB2) has been known as an anti-oxidant in treating diabetes mellitus; however, little is known about its effects and underlying mechanisms on diabetic cardiomyopathy. The present study is to explore the molecular targets of GSPB2 responsible for the anti-oxidative effects in db/db mice by quantitative proteomics. GSPB2 (30 mg/kg body weight/day) were intragastric administrated to db/db mice for 10 weeks. Proteomics of the heart tissue extracts by isobaric tags for relative and absolute quantification analysis was obtained from db/db mice. Our study provides important evidence that GSPB2 protect against cardiomyopathy in diabetes mellitus, which are believed to result from regulating the expression of key proteins involving cardiac fibrosis and proliferation. GSPB2 could be expected to become novel clinical application in fighting against diabetic cardiomyopathy.
Screening micro-organisms for cadmium absorption from aqueous solution and cadmium absorption properties of Arthrobacter nicotianae
Authors: Tsuruta Takehiko , Umenai Daishi , Hatano Tomonobu , Hirajima Tsuyoshi , Sasaki Keiko
Published: June 2014

To obtain basic information on how microbial cells absorb cadmium from aqueous solution, we examined cadmium absorption in various micro-organisms. Of 51 micro-organism strains tested, we found that some Gram-positive bacteria, such as, Arthrobacter nicotianae and Bacillus subtilis, and some actinomycetes, such as, Streptomyces flavoviridis and S. levoris were highly capable of absorbing cadmium from an aqueous solution. A. nicotianae absorbed the largest amount of cadmium, over 800 μmol cadmium per gram of dry wt. cells. However, cadmium absorption by A. nicotianae was affected by the solution pH, cadmium concentration, and cell density. The absorption of cadmium was very rapid. Some factors that affected cadmium absorption by A. nicotianae cells were also discussed.
The human bitter taste receptor hTAS2R39 is the primary receptor for the bitterness of theaflavins
Authors: Yamazaki Toyomi , Sagisaka Miki , Ikeda Riko , Nakamura Toshiyuki , Matsuda Noriko , Ishii Takeshi , Nakayama Tsutomu , Watanabe Tatsuo
Published: June 2014

We purified several hundred mgs of four major theaflavins (theaflavin, theaflavin-3-O-gallate, theaflavin-3′-O-gallate, and theaflavin-3,3′-O-digallate). Among the 25 hTAS2Rs expressed in HEK293T cells, hTAS2R39 and hTAS2R14 were activated by theaflavins. Both hTAS2R39 and hTAS2R14 responded to theaflavin-3′-O-gallate. In addition, hTAS2R39 was activated by theaflavin and theaflavin-3,3′-O-gallate, but not by theaflavin-3-O-gallate. In contrast, hTAS2R14 responded to theaflavin-3-O-gallate.