bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical investigation on the hydrodynamic performance of variable length blade tidal turbine: an attribute to enhance energy capture
Authors: Arzu Farhana , Darvishi Hossain Hassanpour , Hashim Roslan Bin , Taherei Ghazvinei Pezhman , Soeb Mahmudur Rahman
Published: November 2016

In the marine industry, it is important to improve the performance of tida turbines to reduce power generation costs. Modification of existing tidal turbine models is necessary to boost performance. The main objective of the present study is to investigate the hydrodynamic performance of a model variable length blade tidal turbine by modifying the baseline rotor to improve the performance using blade element momentum theory (BEMT). The QBlade BEMT simulation results were validated with the available published data and are in good agreement. Furthermore, the key performance parameters (i.e. thrust, moment, and power coefficient) and power output were predicted using the BEMT code for different blade configurations of the model rotor. The simulation results were compared with a standard conventional fixed blade turbine model. Based on the results from the simulations, with the increase in the rotor blade lengths, the performance parameters, particularly peak power coefficients, were observed to be improved up to 10%. The power extraction was also enhanced up to 79% below‐rated tidal velocities without any loss in performance at the rated condition. Hence, the model is more efficient compared to the conventional models.
Flexible iterative receiver architecture for wireless sensor networks: a joint source and channel coding design example
Authors: Brejza Matthew F. , Maunder Robert G. , Al‐Hashimi Bashir M. , Hanzo Lajos
Published: November 2016

Due to their computational complexity, iterative decoder components such as source and channel decoders are usually implemented using specialised dedicated hardware. This leads to the scenario where each different iterative decoder component of the receiver requires its own hardware. Due to their relatively high complexity, many capacity‐approaching techniques proposed in the literature have not yet been invoked in wireless sensor network applications, despite their potential benefits of facilitating a reduced transmission power or extended communication range. Against this background, the authors propose an energy‐efficient architecture comprised of multiple computation unit (CU), which is sufficiently flexible for accommodating different iterative decoder components using the same hardware. In this study, the flexible architecture is applied to Joint Source and Channel Coding (JSCC), comprising the Unary Error Correction (UEC) code, a turbo code and an iterative demodulator. The authors conceive a flexible technique for controlling the hardware, which supports a high hardware‐exploitation ratio for the CU, reaching a utilisation of 88%, compared with 68% achieved in similar solutions reported in the open literature.
Manganese dioxide nanoflakes anchored on reduced graphene oxide with superior electrochemical performance for supercapacitors
Authors: Zhang Lifeng , Du Suqing , Liu Yi , Zheng Peng , Yuan Xiaoyan , Huang Jianfeng , Guo Shouwu
Published: November 2016

Nanostructured manganese dioxide (MnO2)/reduced graphene oxide (RGO) composite is fabricated via a simple hydrothermal process. The MnO2/RGO composite is used to construct supercapacitors as electrodes with high loading mass of active materials. The electrochemical properties of constructed supercapacitors are tested by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. Electrochemical measurements demonstrate that MnO2/RGO electrode exhibits a high specific capacity of 316 F·g−1 at a current density of 200 mA·g−1 and good long‐term cycling stability with capacitance retention of 93% at 500 mA·g−1 after 1000 cycles. The superior electrochemical performance of as‐prepared composite could be mainly attributed to its unique structure, which is composed of MnO2 nanoflakes well‐integrated on the surfaces of RGO.
Surgical Techniques at Cesarean Delivery: A U.S. Survey
Authors: Lyell Deirdre , Power Michael , Murtough Katie , Ness Amen , Anderson Britta , Erickson Kristine , Schulkin Jay
Published: November 2016

Objective To assess the frequency of surgical techniques at cesarean delivery (CD) among U.S. obstetricians.

Methods Members of the American College of Obstetrician Gynecologists were randomly selected and e-mailed an online survey that assessed surgical closure techniques, demographics, and reasons. Data were analyzed using SPSS (IBM Corp., Armonk, New York, United States), descriptive statistics, and analysis of variance.

Results Our response rate was 53%, and 247 surveys were analyzed. A similar number of respondents either “always or usually” versus “rarely or never” reapproximate the rectus muscles (38.4% versus 43.3%, p = 0.39), and close parietal peritoneum (42.5% versus 46.9%, p = 0.46). The most frequently used techniques were double-layer hysterotomy closure among women planning future children (73.3%) and suturing versus stapling skin (67.6%); the least frequent technique was closure of visceral peritoneum (12.2%). Surgeons who perform double-layer hysterotomy closure had fewer years in practice (15.0 versus 18.7 years, p = 0.021); surgeons who close visceral peritoneum were older (55.5 versus 46.4 years old, p < 0.001) and had more years in practice (23.8 versus 13.8 years practice; p < 0.001).

Conclusion Similar numbers of obstetricians either reapproximate or leave open the rectus muscles and parietal peritoneum at CD, suggesting that wide variation in practice exists. Surgeon demographics and safety concerns play a role in some techniques.
On elliptic algebras and large-n supersymmetric gauge theories
Authors: Koroteev Peter , Sciarappa Antonio
Published: November 2016

In this note we further develop the duality between supersymmetric gauge theories in various dimensions and elliptic integrable systems such as Ruijsenaars-Schneider model and periodic intermediate long wave hydrodynamics. These models arise in instanton counting problems and are described by certain elliptic algebras. We discuss the correspondence between the two types of models by employing the large-n limit of the dual gauge theory. In particular, we provide non-Abelian generalization of our previous result on the intermediate long wave model.
Tradeoffs between oscillator strength and lifetime in terahertz quantum cascade lasers
Authors: Chan Chun Wang I. , Albo Asaf , Hu Qing , Reno John L.
Published: November 2016

Contemporary research into diagonal active region terahertz quantum cascade lasers for high temperature operation has yielded little success. We present evidence that the failure of high diagonality alone as a design strategy is due to a fundamental trade-off between large optical oscillator strength and long upper-level lifetime. We hypothesize that diagonality needs to be paired with increased doping in order to succeed, and present evidence that highly diagonal designs can benefit from much higher doping than normally found in terahertz quantum cascade lasers. In assuming the benefits of high diagonality paired with high doping, we also highlight important challenges that need to be overcome, specifically the increased importance of carrier induced band-bending and impurity scattering.
DFT and TDDFT study on cation-π complexes of diboryne (NHC → B ≡ B←NHC)
Authors: Bania Kusum K. , Guha Ankur Kanti , Bhattacharyya Pradip K.
Published: November 2016

In this study, density functional theory calculation on mono-cationic cation-π complexes of diborynes has been made to understand the interaction in cation-π complexes of diboryne. Results suggest that apart from the smaller cations Li+ and Na+, larger cation like K+ ion could also form complexes with diboryne compounds via cation-π interaction. From the calculated structural and spectroscopic analysis 11B, 13C NMR (Nuclear Magnetic Resonance), FTIR (Fourier Transform Infra red) (force constant, value), and UV-vis spectra, it is found that the interaction between the cations and π-electron cloud of the diboryne is purely electrostatic. It is also observed that smaller cation (Li+) with high electronegativity interacts more strongly compared to larger cation (K+). Calculated interaction energy advocates that the π-electron cloud of the B2 unit contributes more to the cation-π interaction than the two aromatic phenyl rings of the NHC (N-heterocyclic carbene) substituted with 2,6-diisopropylphenyl group. The aryl substituent at the NHC-ligands undergoes a change in spatial orientation with respect to the size of cations in order to provide suitable space to the cations for effective cation-π interaction. Quantum theory of atoms in molecules study clarifies further the nature and extent of B-B and B2-cation interactions.11B-NMR, 13C-NMR, and time dependent density functional theory analysis indicate that cation-π interaction annihilates the B → C (NHC) π-back donation and favours the B≡B bond formation.
Association of a multifunctional ionic block copolymer in a selective solvent
Authors: Etampawala Thusitha N. , Aryal Dipak , Osti Naresh C. , He Lilin , Heller William T. , Willis Carl L. , Grest Gary S. , Perahia Dvora
Published: November 2016

The self-assembly of multiblock copolymers in solutions is controlled by a delicate balance between inherent phase segregation due to incompatibility of the blocks and the interaction of the individual blocks with the solvent. The current study elucidates the association of pentablock copolymers in a mixture of selective solvents which are good for the hydrophobic segments and poor for the hydrophilic blocks using small angle neutron scattering (SANS). The pentablock consists of a center block of randomly sulfonated polystyrene, designed for transport, tethered to poly-ethylene-r-propylene and end-capped by poly-t-butyl styrene, for mechanical stability. We find that the pentablock forms ellipsoidal core-shell micelles with the sulfonated polystyrene in the core and Gaussian decaying chains of swollen poly-ethylene-r-propylene and poly-t-butyl styrene tertiary in the corona. With increasing solution concentration, the size of the micelle, the thickness of the corona, and the aggregation number increase, while the solvent fraction in the core decreases. In dilute solution the micelle increases in size as the temperature is increased, however, temperature effects dissipate with increasing solution concentration.
Point defect reduction in wide bandgap semiconductors by defect quasi Fermi level control
Authors: Reddy P. , Hoffmann M. P. , Kaess F. , Bryan Z. , Bryan I. , Bobea M. , Klump A. , Tweedie J. , Kirste R. , Mita S. , Gerhold M. , Collazo R. , Sitar Z.
Published: November 2016

A theoretical framework for a general approach to reduce point defect density in materials via control of defect quasi Fermi level (dQFL) is presented. The control of dQFL is achieved via excess minority carrier generation. General guidelines for controlling dQFL that lead to a significant reduction in compensating point defects in any doped material is proposed. The framework introduces and incorporates the effects of various factors that control the efficacy of the defect reduction process such as defect level, defect formation energy, bandgap, and excess minority carrier density. Modified formation energy diagrams are proposed, which illustrate the effect of the quasi Fermi level control on the defect formation energies. These formation energy diagrams provide powerful tools to determine the feasibility and requirements to produce the desired reduction in specified point defects. An experimental study of the effect of excess minority carriers on point defect incorporation in GaN and AlGaN shows an excellent quantitative agreement with the theoretical predictions. Illumination at energies larger than the bandgap is employed as a means to generate excess minority carriers. The case studies with CN in Si doped GaN, H and VN in Mg doped GaN and VM-2ON in Si doped Al0.65Ga0.35N revealed a significant reduction in impurities in agreement with the proposed theory. Since compensating point defects control the material performance (this is particularly challenging in wide and ultra wide bandgap materials), dQFL control is a highly promising technique with wide scope and may be utilized to improve the properties of various materials systems and performance of devices based upon them.
Potential surface waves at the vacuum-radiative collisional plasma interface
Authors: Khan Arroj A. , Rozina Ch. , Jamil M.
Published: November 2016

The stability of potential surface waves at the interface of collisional radiative electron-ion plasma and a vacuum is investigated. It is shown that the dynamics of electrons are affected by electromagnetic thermal radiation pressure significantly. The fluid model along with full set of Maxwell's equations is used to develop dispersion relation of electrostatic surface waves on hot homogeneous radiative collisional plasma. It is found that electrostatic surface waves become unstable in the presence of electromagnetic thermal radiation and self collision of plasma particles; however, thermal radiations stabilize the surface waves in the absence of collisions. The analytical results are verified numerically for both the laboratory and ionosphere plasma environment. The study of surface waves may seek its applications at the nano as well as the astroscales.
Surface smoothing during plasma etching of Si in Cl2
Authors: Nakazaki Nobuya , Matsumoto Haruka , Tsuda Hirotaka , Takao Yoshinori , Eriguchi Koji , Ono Kouichi
Published: November 2016

Effects of initial roughness on the evolution of plasma-induced surface roughness have been investigated during Si etching in inductively coupled Cl2 plasmas, as a function of rf bias power or ion incident energy in the range Ei ≈ 20–500 eV. Experiments showed that smoothing of initially rough surfaces as well as non-roughening of initially planar surfaces can be achieved by plasma etching in the smoothing mode (at high Ei) with some threshold for the initial roughness, above which laterally extended crater-like features were observed to evolve during smoothing. Monte Carlo simulations of the surface feature evolution indicated that the smoothing/non-roughening is attributed primarily to reduced effects of the ion scattering or reflection from microscopically roughened feature surfaces on incidence.
The interplay of network structure and dispatch solutions in power grid cascading failures
Authors: Reynolds-Barredo Jose M. , Newman David E. , Carreras Benjamin A. , Dobson Ian
Published: November 2016

For a given minimum cost of the electricity dispatch, multiple equivalent dispatch solutions may exist. We explore the sensitivity of networks to these dispatch solutions and their impact on the vulnerability of the network to cascading failure blackouts. It is shown that, depending on the heterogeneity of the network structure, the blackout statistics can be sensitive to the dispatch solution chosen, with the clustering coefficient of the network being a key ingredient. We also investigate mechanisms or configurations that decrease discrepancies that can occur between the different dispatch solutions.
Effect of cooling rate on phase transitions and ferroelectric properties in 0.75BiFeO3-0.25BaTiO3 ceramics
Authors: Kim Dae Su , Cheon Chae Il , Lee Seong Su , Kim Jeong Seog
Published: November 2016

The effect of the cooling rate on the electrical properties was investigated in the 0.75BiFeO3-0.25BaTiO3 ceramics. The air-quenched samples had superior ferroelectric and piezoelectric properties to the slowly cooled samples. The quenching effect weakened when the quenching temperature was less than 700 °C and eventually disappeared at 500 °C and below. The X-ray diffraction and transmission electron microscopy showed that the cooling rate had a significant effect on the crystal structure and domain structure. The slowly cooled sample showed a very small rhombohedral distortion and a poorly developed domain structure, which leads to weak ferroelectric and piezoelectric properties at room temperature. The quenched and slowly cooled samples had a ferroelectric rhombohedral structure (R3c) at room temperature and a paraelectric cubic structure (Pm-3m) at temperatures above 650 °C. On the other hand, the slowly cooled sample had a centro-symmetric orthorhombic (Pbnm) structure at intermediate temperatures, while the quenched sample had a noncentrosymmetric orthorhombic structure (Amm2). The diffusion of oxygen vacancies in the slowly cooled sample is believed to lead to a more symmetric orthorhombic structure at intermediate temperatures between 500 °C and 650 °C during the slow-cooling process and consequently very small rhombohedral distortion at room temperature.
Spontaneous cracking of amorphous solid water films and the dependence on microporous structure
Authors: Bu Caixia , Dukes Catherine A. , Baragiola Raúl A.
Published: November 2016

Vapor-deposited, porous, amorphous, water-ice films, also called amorphous solid water (ASW), crack spontaneously during growth when the film thickness exceeds a critical value (Lc). We measured the Lc during growth of ASW films as a function of growth temperature (Tg = 10 K, 30 K, and 50 K) and deposition angle (θ = 0°, 45°, and 55°) using a quartz crystal microbalance, an optical interferometer, and an infrared spectrometer. The critical thickness, 1–5 μm under our experimental conditions, increases with Tg and θ, an indication of film porosity. We suggest that ASW films undergo tensile stress due to the mismatch between substrate adhesion and contracting forces derived from the incompletely coordinated molecules on the surfaces of the pores. We provide a model to explain the observed dependences of Lc on the Tg and θ in the context of Griffith theory and estimate the tensile strength of low-temperature ASW to be ∼25–40 MPa. Our model can be applied more generally to describe fracture of other solids with microporous structures, such as metallic or ceramic materials with voids.
Plasmonic hole arrays for combined photon and electron management
Authors: Liapis Andreas C. , Sfeir Matthew Y. , Black Charles T.
Published: November 2016

Material architectures that balance optical transparency and electrical conductivity are highly sought after for thin-film device applications. However, these are competing properties, since the electronic structure that gives rise to conductivity typically also leads to optical opacity. Nanostructured metal films that exhibit extraordinary optical transmission, while at the same time being electrically continuous, offer considerable flexibility in the design of their transparency and resistivity. Here, we present design guidelines for metal films perforated with arrays of nanometer-scale holes, discussing the consequences of the choice of nanostructure dimensions, of the type of metal, and of the underlying substrate on their electrical, optical, and interfacial properties. We experimentally demonstrate that such films can be designed to have broad-band optical transparency while being an order of magnitude more conductive than indium tin oxide. Prototypical photovoltaic devices constructed with perforated metal contacts convert ∼18% of the incident photons, compared to <1% for identical devices having contacts without the hole array.
Realization of low power-laser induced thermionic emission from Ag nanoparticle-decorated CNT forest: A consequence of surface plasmon resonance
Authors: Monshipouri Mahta , Abdi Yaser , Darbari Sara
Published: November 2016

Enhancement of electron emission from Ag nanoparticle-decorated carbon nanotube (CNT) forest, using low power-lasers, is reported in this work. Realization of thermionic emission from CNTs using the low power laser can be achievable when the CNT forest is illuminated by a narrow laser beam which leads to localized heating of the CNT forest surface. For this purpose, CNT forest was decorated with Ag nanoparticles. Surface plasmon resonance of Ag nano-particles led to intense local electric field which is responsible for localized heating and thermionic emission from CNTs. Enhancement of emission current from CNTs depends on the wavelength of the excitation laser, so that matching the wavelength of laser to the wavelength of the plasmon resonance leaded to a maximum enhancement in electron emission.
Exchange stiffness in ultrathin perpendicularly magnetized CoFeB layers determined using the spectroscopy of electrically excited spin waves
Authors: Devolder T. , Kim J.-V. , Nistor L. , Sousa R. , Rodmacq B. , Diény B.
Published: November 2016

We measure the frequencies of spin waves in nm-thick perpendicularly magnetized FeCoB systems, and model the frequencies to deduce the exchange stiffness of this material in the ultrathin limit. For this, we embody the layers in magnetic tunnel junctions patterned into circular nanopillars of diameters ranging from 100 to 300 nm, and we use magneto-resistance to determine which rf-current frequencies are efficient in populating the spin wave modes. Micromagnetic calculations indicate that the ultrathin nature of the layer and the large wave vectors used ensure that the spin wave frequencies are predominantly determined by the exchange stiffness, such that the number of modes in a given frequency window can be used to estimate the exchange stiffness. For 1 nm layers, the experimental data are consistent with an exchange stiffness A=20±2 pJ/m, which is slightly lower than its bulk counterpart. The thickness dependence of the exchange stiffness has strong implications for the numerous situations that involve ultrathin films hosting strong magnetization gradients, and the micromagnetic description thereof.
A patch-array antenna single-mode low electrical dissipation continuous wave terahertz quantum cascade laser
Authors: Bosco L. , Bonzon C. , Ohtani K. , Justen M. , Beck M. , Faist J.
Published: November 2016

We introduce a double metal terahertz quantum cascade laser meant for astrophysical heterodyne measurements. The laser ridge is embedded in benzocyclobutene, and the device exhibits single mode, continuous wave operation around 4.745 THz with a peak power of almost 1.8 mW at 10 K and a power consumption of ≈1.6 W. Moreover, thanks to the integration of a top metal contact with a patch array antenna for light out-coupling the beam of the emitted light has a low-divergence single-lobe profile and an FWHM of ≈30°.
Scalable synchronization of spin-Hall oscillators in out-of-plane field
Authors: Puliafito V. , Giordano A. , Laudani A. , Garescì F. , Carpentieri M. , Azzerboni B. , Finocchio G.
Published: November 2016

A strategy for a scalable synchronization of an array of spin-Hall oscillators (SHOs) is illustrated. In detail, we present the micromagnetic simulations of two and five SHOs realized by means of couples of triangular golden contacts on the top of a Pt/CoFeB/Ta trilayer. The results highlight that the synchronization occurs for the whole current region that gives rise to the excitation of self-oscillations. This is linked to the role of the magnetodipolar coupling, which is the phenomenon driving the synchronization when the distance between oscillators is not too large. Synchronization also turns out to be robust against geometrical differences of the contacts, simulated by considering variable distances between the tips ranging from 100 nm to 200 nm. Besides, it entails an enlargement of the radiation pattern that can be useful for the generation of spin-waves in magnonics applications. Simulations performed to study the effect of the interfacial Dzyaloshinskii-Moriya interaction show nonreciprocity in spatial propagation of the synchronized spin-wave. The simplicity of the geometry and the robustness of the achieved synchronization make this design of array of SHOs scalable for a larger number of synchronized oscillators.
Intrinsic spin dynamics in optically excited nanoscale magnetic tunnel junction arrays restored by dielectric coating
Authors: Jaris M. , Yahagi Y. , Mahato B. K. , Dhuey S. , Cabrini S. , Nikitin V. , Stout J. , Hawkins A. R. , Schmidt H.
Published: November 2016

We report the all-optical observation of intrinsic spin dynamics and extraction of magnetic material parameters from arrays of sub-100 nm spin-transfer torque magnetic random access memory (STT-MRAM) devices with a CoFeB/MgO interface. To this end, the interference of surface acoustic waves with time-resolved magneto-optic signals via magneto-elastic coupling was suppressed using a dielectric coating. The efficacy of this method is demonstrated experimentally and via modeling on a nickel nanomagnet array. The magnetization dynamics for both coated nickel and STT-MRAM arrays shows a restored field-dependent Kittel mode from which the effective damping can be extracted. We observe an increased low-field damping due to extrinsic contributions from magnetic inhomogeneities and variations in the nanomagnet shape, while the intrinsic Gilbert damping remains unaffected by patterning. The data are in excellent agreement with a local resonance model and have direct implications for the design of STT-MRAM devices as well as other nanoscale spintronic technologies.
How plasma induced oxidation, oxygenation, and de-oxygenation influences viability of skin cells
Authors: Oh Jun-Seok , Strudwick Xanthe , Short Robert D. , Ogawa Kotaro , Hatta Akimitsu , Furuta Hiroshi , Gaur Nishtha , Hong Sung-Ha , Cowin Allison J. , Fukuhara Hideo , Inoue Keiji , Ito Masafumi , Charles Christine , Boswell Roderick W. , Bradley James W. , Graves David B. , Szili Endre J.
Published: November 2016

The effect of oxidation, oxygenation, and de-oxygenation arising from He gas jet and He plasma jet treatments on the viability of skin cells cultured in vitro has been investigated. He gas jet treatment de-oxygenated cell culture medium in a process referred to as “sparging.” He plasma jet treatments oxidized, as well as oxygenated or de-oxygenated cell culture medium depending on the dissolved oxygen concentration at the time of treatment. He gas and plasma jets were shown to have beneficial or deleterious effects on skin cells depending on the concentration of dissolved oxygen and other oxidative molecules at the time of treatment. Different combinations of treatments with He gas and plasma jets can be used to modulate the concentrations of dissolved oxygen and other oxidative molecules to influence cell viability. This study highlights the importance of a priori knowledge of the concentration of dissolved oxygen at the time of plasma jet treatment, given the potential for significant impact on the biological or medical outcome. Monitoring and controlling the dynamic changes in dissolved oxygen is essential in order to develop effective strategies for the use of cold atmospheric plasma jets in biology and medicine.
Model for the architecture of caveolae based on a flexible, net-like assembly of Cavin1 and Caveolin discs
Authors: Stoeber Miriam , Schellenberger Pascale , Siebert C. Alistair , Leyrat Cedric , Helenius Ari , Grünewald Kay
Published: November 2016

Significance

The surface of mammalian cells contains abundant plasma membrane invaginations termed “caveolae.” Caveolae are important for various cellular functions, e.g. signaling, membrane regulation, and vesicular trafficking. Assembly and stability of caveolae depends on a protein coat formed by complexes of cavin and caveolin proteins whose structure has remained elusive. To understand the architecture of caveolae, we structurally analyzed cavin and caveolin complexes and visualized caveolae in cells by electron cryomicroscopy. A regular polyhedron emerged as the most likely architectural principle of caveolae. Polyhedra provide the underlying principle in many biological structures in which spherical curvature is imposed by proteins. We suggest a model for the caveolar coat architecture based on regularly arranged, net-like cavin assemblies and disc-shaped caveolin oligomers.
De la tierra al aire
Authors: Quílez Luis Bagué
Published: November 2016

This article analyzes the representation of nature in Aníbal Núñez’s poetry, halfway between the ecological commitment and the elegy for the environmental disaster. While the poet’s initial books show the parallels between nature-based fables and advertising codes, since Naturaleza no recuperable there is a continuous transformation of landscape into culture, as well as a progressive loss of nature’s real sense and a degradation of its moral substance. From then on, the depiction of nature adopts the descriptive neutrality of historical chronicles (Estampas de ultramar), takes refuge in art (Figura en un paisaje), or is dissolved in the funerary performance of ruins (Alzado de la ruina). More generally, Aníbal Núñez’s symbolic world offers a metaphorical transposition of postmodern vacuum and advances the role that certain topoi (locus amœnus, beatus ille) play in contemporary Spanish poetry.
Power consumption and friction coefficient in the ultrasonic consolidation of aluminium alloys
Authors: Yi D. , Zhang S. , Zhang H. , Zheng L. , Norfolk M.
Published: November 2016

Energy input and friction behaviour are two of the key phenomena related with the welding bond of ultrasonic consolidation (UC) process. In this study, the effects of welding parameters, such as the building height, travel speed, oscillation amplitude and applied force, on the power consumption of the horn and friction coefficient of the welding interface of UC are investigated for aluminium alloys 2024 and 7075. Multiple regression equations are developed to estimate the power consumption and friction coefficient using the welding parameters. A line-contact friction test is performed to examine the friction coefficient of UC under the various applied forces and preheating temperatures. The quantitative relationships among the welding parameters, friction coefficient and power consumption are derived.
Effect of O-methylated and glucuronosylated flavonoids from Tamarix gallica on α-glucosidase inhibitory activity: structure–activity relationship and synergistic potential
Authors: Ben Hmidene Asma , Smaoui Abderrazak , Abdelly Chedly , Isoda Hiroko , Shigemori Hideyuki
Published: November 2016

O-Methylated and glucuronosylated flavonoids were isolated from Tamarix gallica as α-glucosidase inhibitors. Structure–activity relationship of these flavonoids suggests that catechol moiety and glucuronic acid at C-3 are factors in the increase in α-glucosidase inhibitory activity. Furthermore, rhamnetin, tamarixetin, rhamnazin, KGlcA, KGlcA-Me, QGlcA, and QGlcA-Me exhibit synergistic potential when applied with a very low concentration of acarbose to α-glucosidase from rat intestine.
GTPase cross talk regulates TRAPPII activation of Rab11 homologues during vesicle biogenesis
Authors: Thomas Laura L. , Fromme J. Christopher
Published: November 2016

Rab guanosine triphosphatases (GTPases) control cellular trafficking pathways by regulating vesicle formation, transport, and tethering. Rab11 and its paralogs regulate multiple secretory and endocytic recycling pathways, yet the guanine nucleotide exchange factor (GEF) that activates Rab11 in most eukaryotic cells is unresolved. The large multisubunit transport protein particle (TRAPP) II complex has been proposed to act as a GEF for Rab11 based on genetic evidence, but conflicting biochemical experiments have created uncertainty regarding Rab11 activation. Using physiological Rab-GEF reconstitution reactions, we now provide definitive evidence that TRAPPII is a bona fide GEF for the yeast Rab11 homologues Ypt31/32. We also uncover a direct role for Arf1, a distinct GTPase, in recruiting TRAPPII to anionic membranes. Given the known role of Ypt31/32 in stimulating activation of Arf1, a bidirectional cross talk mechanism appears to drive biogenesis of secretory and endocytic recycling vesicles. By coordinating simultaneous activation of two essential GTPase pathways, this mechanism ensures recruitment of the complete set of effectors needed for vesicle formation, transport, and tethering.
Spatial model of convective solute transport in brain extracellular space does not support a “glymphatic” mechanism
Authors: Jin Byung-Ju , Smith Alex J. , Verkman Alan S.
Published: November 2016

A “glymphatic system,” which involves convective fluid transport from para-arterial to paravenous cerebrospinal fluid through brain extracellular space (ECS), has been proposed to account for solute clearance in brain, and aquaporin-4 water channels in astrocyte endfeet may have a role in this process. Here, we investigate the major predictions of the glymphatic mechanism by modeling diffusive and convective transport in brain ECS and by solving the Navier–Stokes and convection–diffusion equations, using realistic ECS geometry for short-range transport between para-arterial and paravenous spaces. Major model parameters include para-arterial and paravenous pressures, ECS volume fraction, solute diffusion coefficient, and astrocyte foot-process water permeability. The model predicts solute accumulation and clearance from the ECS after a step change in solute concentration in para-arterial fluid. The principal and robust conclusions of the model are as follows: (a) significant convective transport requires a sustained pressure difference of several mmHg between the para-arterial and paravenous fluid and is not affected by pulsatile pressure fluctuations; (b) astrocyte endfoot water permeability does not substantially alter the rate of convective transport in ECS as the resistance to flow across endfeet is far greater than in the gaps surrounding them; and (c) diffusion (without convection) in the ECS is adequate to account for experimental transport studies in brain parenchyma. Therefore, our modeling results do not support a physiologically important role for local parenchymal convective flow in solute transport through brain ECS.
New Technique: Acute Minced Expansion Graft of Traumatic Wound Tissue
Authors: Klapper Andrew Mark , Moradian Scott , Pack Philip
Published: November 2016

OBJECTIVES:

Superficial soft tissue injury, such as a skin tear, is common. For such wounds, the authors introduce a novel technique that allows the physician to salvage otherwise discarded tissue as a traumatic graft to highly accelerate wound healing.

METHODS:

A series of 11 patients with superficial soft tissue trauma in which debrided tissues are salvaged back into the wound by means of minced expansion grafting (MEG) are followed from presentation through healing.

RESULTS:

Salvaged tissue replaced back into wounds as MEG grafts greatly accelerated epithelialization and wound closure.

CONCLUSIONS:

Based on their experience with MEG, the authors introduce a new principle for the wound surgeon that no tissue should ever be discarded, but rather salvaged and placed back into the wound.
Nonhealing Wounds Caused by Brown Spider Bites: Application of Hyperbaric Oxygen Therapy
Authors: Hadanny Amir , Fishlev Gregory , Bechor Yair , Meir Oshra , Efrati Shai
Published: November 2016

BACKGROUND:

Bites by Loxosceles spiders (also known as recluse spiders or brown spiders) can cause necrotic ulcerations of various sizes and dimensions. The current standard of care for brown spider bites includes analgesics, ice, compression, elevation, antihistamines, and surgical debridement. Hyperbaric oxygen therapy (HBOT) in the treatment of brown spider bites has been administered in the early stage of ulceration, or 2 to 6 days after the bite. Unfortunately, the diagnosis of spider bite–related ulcers is often delayed and weeks or months may elapse before HBOT is considered.

OBJECTIVE:

To evaluate the effect of HBOT on nonhealing wounds caused by brown spider bites in the late, chronic, nonhealing stage.

METHODS:

Analysis of 3 patients with brown spider-bite healing wounds treated at The Sagol Center for Hyperbaric Medicine and Research in Israel. Patients presented 2 to 3 months after failure of other therapies including topical dressings, antibiotics, and corticosteroids. All patients were treated with daily 2 ATA (atmospheres absolute) with 100% oxygen HBOT sessions.

RESULTS:

All 3 patients were previously healthy without any chronic disease. Their ages were 30, 42, and 73 years. They were treated once daily for 13, 17, and 31 sessions, respectively. The wounds of all 3 patients healed, and there was no need for additional surgical intervention. There were no significant adverse events in any of the patients.

CONCLUSIONS:

Microvascular injury related to brown spider bites may culminate in ischemic nonhealing wounds even in a relatively young, healthy population. Hyperbaric oxygen therapy should be considered as a valuable therapeutic tool even months after the bite.
Efficacy of Monitoring Devices in Support of Prevention of Pressure Injuries
Authors: Walia Gurjot S. , Wong Alison L. , Lo Andrea Y. , Mackert Gina A. , Carl Hannah M. , Pedreira Rachel A. , Bello Ricardo , Aquino Carla S. , Padula William V. , Sacks Justin M.
Published: November 2016

GENERAL PURPOSE:

To present a systematic review of the literature assessing the efficacy of monitoring devices for reducing the risk of developing pressure injuries.

TARGET AUDIENCE:

This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care.

LEARNING OBJECTIVES/OUTCOMES:

After participating in this educational activity, the participant should be better able to:1. Explain the methodology of the literature review and its results.2. Discuss the scope of the problem and the implications of the research.

OBJECTIVE: To assess the efficacy of monitoring devices for reducing the risk of developing pressure injuries (PIs).

DATA SOURCES: The authors systematically reviewed the literature by searching PubMed/MEDLINE and CINAHL databases through January 2016.

STUDY SELECTION: Articles included clinical trials and cohort studies that tested monitoring devices, evaluating PI risk factors on patients in acute and skilled nursing settings. The articles were scored using the Methodological Index for Non-randomized Studies.

DATA EXTRACTION: Using a standardized extraction form, the authors extracted patient inclusion/exclusion criteria, care setting, key baseline, description of monitoring device and methodology, number of patients included in each group, description of any standard of care, follow-up period, and outcomes.

DATA SYNTHESIS: Of the identified 1866 publications, 9 met the inclusion criteria. The high-quality studies averaged Methodological Index for Non-randomized Studies scores of 19.4 for clinical trials and 12.2 for observational studies. These studies evaluated monitoring devices that measured interface pressure, subdermal tissue stress, motion, and moisture. Most studies found a statistically significant decrease in PIs; 2 studies were eligible for meta-analysis, demonstrating that use of monitoring devices was associated with an 88% reduction in the risk of developing PIs (Mantel-Haenszel risk ratio, 0.12; 95% confidence interval, 0.04–0.41; I
2 = 0%).

CONCLUSIONS: Pressure injury monitoring devices are associated with a strong reduction in the risk of developing PIs. These devices provide clinicians and patients with critical information to implement prevention guidelines. Randomized controlled trials would help assess which technologies are most effective at reducing the risk of developing PIs.
Evaluation of the Efficacy of Highly Hydrophilic Polyurethane Foam Dressing in Treating a Diabetic Foot Ulcer
Authors: Jung Jae-A , Yoo Ki-Hyun , Han Seung-Kyu , Dhong Eun-Sang , Kim Woo-Kyung
Published: November 2016

OBJECTIVE:

To demonstrate the efficacy of a highly hydrophilic polyurethane foam dressing in the treatment of diabetic ulcers.

BACKGROUND:

Diabetic foot ulcers often pose a difficult treatment problem. Polyurethane foam dressings have been used worldwide to accelerate wound healing, but only a few clinical studies demonstrate the effect of foam dressing on the healing of diabetic ulcers.

METHODS:

Medical records of 1342 patients with diabetic ulcers who were admitted and treated at the authors’ institution were reviewed. A total of 208 patients met the study’s inclusion criteria. Of these 208 patients, 137 were treated with a highly hydrophilic polyurethane foam dressing, and 71 were treated with saline gauze (control group). Except for the application of polyurethane foam dressing, the treatment method was identical for patients in both groups. The wound healing outcomes of the 2 groups were compared.

RESULTS:

Complete wound healing occurred in 87 patients (63.5%) in the polyurethane foam dressing group and in 28 patients (39.4%) in the control group within 12 weeks (P < .05, X2
test). The mean percentage of wound area reduction in both groups was statistically significant (P < .05, Mann-Whitney U test). The mean time required for complete closure in patients who achieved complete healing within 12 weeks was 6.2 (SD, 3.4) weeks and 7.3 (SD, 2.6) weeks in the polyurethane foam dressing and control groups, respectively (P < .05, Mann-Whitney U test).

CONCLUSION:

These results indicate that the highly hydrophilic polyurethane foam dressing may provide an effective treatment strategy for diabetic foot ulcers.
Scapular body fracture and concomitant inferior angle apophyseal separation with intrathoracic displacement: a case report
Authors: Park Ho Youn , Jang Hyuk Jin , Sur Yoo Joon
Published: November 2016

A 10-year-old patient presented to the emergency room after a motor vehicle accident. The patient was diagnosed with left scapular body fracture and concomitant inferior angle apophyseal separation with intrathoracic displacement causing hemopneumothorax. The displaced scapular body was reduced surgically and separated apophysis of the inferior angle was fixed to the scapular body with absorbable suture. Postoperative 2-year follow-up showed a good result. A literature search found two pediatric cases of intrathoracic displacement of scapular body fracture. There was no previous report of apophyseal separation of the inferior angle of the scapula.
Broadening the Anatomic Landscape of Sclerosing Perineurioma: A Series of 5 Cases in Nonacral Sites
Authors: Erstine Emily M. , Ko Jennifer S. , Rubin Brian P. , McKenney Jesse K. , Goldblum John R. , Billings Steven D.
Published: November 2016

Sclerosing perineurioma is a rare perineurioma variant thought to occur almost exclusively in digits and palms, predominantly in young adult men. It clinically presents as a solitary slow-growing nodule, sometimes associated with prior trauma. Since 01/01/2000, our institution has received 5 cases in consultation of sclerosing perineurioma presenting in atypical locations. Four of 5 patients were women. The median age at presentation was 45 years (range, 31–62 years). Sites included dorsal tongue, anterior neck, mid upper back, forearm, and proximal anterior thigh. Complete clinical histories were not available, although lesions were reported as subcentimeter nodules with at least 1 suspected to have formed after trauma. Histologically, all lesions were circumscribed to dermal/submucosal tumors. Some extended into subcutaneous fat. The neoplasms were composed of an admixture of bland spindled to epithelioid cells with uniform, wavy, thin-to-oval nuclei forming linear cords to whorled sheets in an extensively hyalinized stroma. Mitotic activity was inconspicuous. All tumors expressed epithelial membrane antigen and were negative for S100 protein. All cases stained for CD34 were positive (3/3). This series highlights a broader clinical presentation of sclerosing perineurioma than previously recognized. Acknowledgment of this anatomic variability should provide confidence to dermatopathologists faced with similar cases.
Does Uric Acid Level Provide Additional Risk Stratification Information in Emergency Patients With Symptoms of Possible Acute Coronary Syndrome?
Authors: Jin Harry , Greenslade Jaimi H. , Parsonage William A. , Hawkins Tracey , Than Martin , Cullen Louise
Published: November 2016

Objective:

Elevated uric acid levels have been associated with the presence and severity of coronary artery disease (CAD). This study aimed to assess the clinical utility of serum uric acid levels to identify patients at high risk of acute coronary syndrome (ACS) in those who presented to the emergency department (ED) with chest pain.

Methods:

This was a prospective observational study of 951 adult patients who were being evaluated for ACS in a single ED. Serum uric acid was taken on presentation. Patients were followed up 30 days and 1 year after initial presentation. The primary outcome was a diagnosis of ACS within 30 days of initial attendance. A logistic regression analysis was performed to identify whether elevated uric acid levels were predictive of ACS. Kaplan–Meier curves were generated to identify 1-year mortality in those who were available for 1-year follow-up and Cox regression was performed to identify whether uric acid levels were an independent predictor of mortality.

Results:

ACS was diagnosed in 88 patients and 140 patients had elevated uric acid levels. A total of 679 patients agreed to 1-year follow-up. Elevated uric acid levels were not associated with a diagnosis of ACS (p = 0.96). Patients with elevated uric acid had a higher 1-year death rate (8/101; 7.92%) compared with patients with normal uric acid levels (12/596; 2.01%, p < 0.01).

Conclusions:

Uric acid levels lack diagnostic utility for ACS but may be useful for identifying ED patients with chest pain who are at high risk for 1-year mortality. Elevated uric acid levels correlate with the presence of other risk factors of CAD and are a marker for poor long-term outcome.
Red Cell Distribution Width and Severe Left Ventricular Dysfunction in Ischemic Heart Failure
Authors: Bozorgi Ali , Mehrabi Nasab Entezar , Khoshnevis Maryam , Dogmehchi Enseyeh , Hamze Gita , Goodarzynejad Hamidreza
Published: November 2016

Objective:

The red cell distribution width (RDW), a simple and widely available marker, has been linked with an increased risk of adverse outcomes in patients with heart failure (HF) and risk of death, and cardiovascular events in those with previous myocardial infarction, but its relation with the severity of left ventricular (LV) dysfunction is not fully investigated. The aim of this study was to assess the prognostic value of the RDW in post myocardial infarction patients with typical signs and symptoms of HF and with reduced LV ejection fraction (EF).

Methods:

Patients (n = 350) came from an ongoing registry of consecutive patients who admitted for ischemic heart disease at our center. All patients were followed up 1 year after the initial hospitalization by telephone interviews. The outcomes studied were mortality and hospitalization because of decompensated HF.

Results:

RDW-coefficient of variation (express in percentage) was calculated from SD of mean corpuscular volume and mean corpuscular volume itself. Using logistic regression analysis, 3 variables consisting age, RDW level, and hemoglobin were identified as independent predictors of severe LV dysfunction (LVEF <30%). Levels of RDW were associated with the presence of severe LV dysfunction, with an accuracy of 61.4% (95% confidence interval: 56.2%–66.4%) and 66.9% (95% confidence interval: 61.8%–71.6%), using cut-off values of higher than 13.5 and 13.8, respectively.

Conclusion:

Our results suggest that elevated RDW may be used as a prognostic tool among HF patients with the documented myocardial infarction because it is an inexpensive, rapidly calculated test that is already routinely in use in practice.