bluuebunny/crossref_metadata_2025 huggingface dataset:
ON THE INTERFACE LAW BETWEEN A DEFORMABLE POROUS MEDIUM CONTAINING A VISCOUS FLUID AND AN ELASTIC BODY
Authors: MIKELIĆ ANDRO , WHEELER MARY F.
Published: April 2012

In this paper we undertake a rigorous derivation of the interface conditions between a poroelastic medium (the pay zone) and an elastic body (the non-pay zone). We assume that the poroelastic medium contains a pore structure of the characteristic size ε and that the fluid/structure interaction regime corresponds to diphasic Biot's law. The question is challenging because the Biot's equations for the poroelastic part contain one unknown more than the Navier equations for the non-pay zone. The solid part of the pay zone (the matrix) is elastic and the pores contain a viscous fluid. The fluid is assumed viscous and slightly compressible. We study the case when the contrast of property is of order ε2, i.e. the normal stress of the elastic matrix is of the same order as the fluid pressure. We assume a periodic matrix and obtain the a priori estimates. Then we let the characteristic size of the inhomogeneities tend to zero and pass to the limit in the sense of the two-scale convergence. The obtained effective equations represent a two-scale system for three displacements and two pressures, coupled through the interface conditions with the Navier equations for the elastic displacement in the non-pay zone. We prove that the appropriate interface conditions at the interface between an elastic and a poroelastic medium are: (i) the effective displacement continuity, (ii) the effective normal stress continuity and (iii) the normal Darcy velocity zero from the poroelastic side. In addition we determine the effective boundary conditions for the contact between a poroelastic body and a rigid obstacle, giving us the effective outer boundary conditions.
ELASTIC LIMIT OF SQUARE LATTICES WITH THREE-POINT INTERACTIONS
Authors: MEUNIER NICOLAS , PANTZ OLIVIER , RAOULT ANNIE
Published: April 2012

We derive the equivalent energy of a square lattice that either deforms into the three- dimensional Euclidean space or remains planar. Interactions are not restricted to pairs of points and take into account changes of angles. Under some relationships between the local energies associated with the four vertices of an elementary square, we show that the limit energy can be obtained by mere quasiconvexification of the elementary cell energy and that the limit process does not involve any relaxation at the atomic scale. In this case, it can be said that the Cauchy–Born rule holds true. Our results apply to classical models of mechanical trusses that include torques between adjacent bars and to atomistic models.
THE WIGNER–FOKKER–PLANCK EQUATION: STATIONARY STATES AND LARGE TIME BEHAVIOR
Authors: ARNOLD ANTON , GAMBA IRENE M. , GUALDANI MARIA PIA , MISCHLER STÉPHANE , MOUHOT CLEMENT , SPARBER CHRISTOF
Published: April 2012

We consider the linear Wigner–Fokker–Planck equation subject to confining potentials which are smooth perturbations of the harmonic oscillator potential. For a certain class of perturbations we prove that the equation admits a unique stationary solution in a weighted Sobolev space. A key ingredient of the proof is a new result on the existence of spectral gaps for Fokker–Planck type operators in certain weighted L2-spaces. In addition we show that the steady state corresponds to a positive density matrix operator with unit trace and that the solutions of the time-dependent problem converge towards the steady state with an exponential rate.
WELL-POSEDNESS AND EXPONENTIAL DECAY OF THE ENERGY IN THE NONLINEAR JORDAN–MOORE–GIBSON–THOMPSON EQUATION ARISING IN HIGH INTENSITY ULTRASOUND
Authors: KALTENBACHER BARBARA , LASIECKA IRENA , POSPIESZALSKA MARIA K.
Published: April 2012

We consider a third order in time equation which arises, e.g. as a model for wave propagation in viscous thermally relaxing fluids. This equation displays, even in the linear version, a variety of dynamical behaviors for its solution that depend on the physical parameters in the equation. These range from non-existence and instability to exponential stability (in time) as was shown for the constant coefficient case in Ref. 23. In case of vanishing diffusivity of the sound, there is a lack of generation of a semigroup associated with the linear dynamics. If diffusivity of the sound is positive, the linear dynamics is described by a strongly continuous hyperbolic-like evolution. This evolution is exponentially stable provided sufficiently large viscous damping is accounted for in the model.

In this paper, we consider the full nonlinear model referred to as Jordan–Moore–Gibson–Thompson equation. This model can be seen as a "hyperbolic" version of Kuznetsov's equation, where the linearization of the latter corresponds to an analytic semigroup. This is no longer valid for the presently considered third-order model whose linearization is associated with a group structure.

In order to carry out the analysis of the nonlinear model, we first consider time and space-dependent viscosity which then leads to evolution rather than semigroup generators. Decay rates for both "natural" and "higher" level energies are derived. Relevant physical parameters that are responsible for spectral behavior (continuous and point spectrum) are identified. The theoretical estimates proved in the paper are confirmed by numerical simulations. The derived energy estimates are then used in order to establish global well-posedness and exponential decay for the solutions to the nonlinear equation.
Modelling the Vale of St Albans: parameter estimation and dual storage
Authors: Taylor A. B. , Martin N. A. , Everard E. , Kelly T. J.
Published: April 2012

The development of the Vale of St Albans groundwater model made use of two techniques not commonly used in UK regional modelling studies: parameter estimation (using PEST) and representation of dual storage. Parameter estimation techniques can significantly improve model calibration and can be used to inform model development. Because parameter estimation typically involves running a groundwater model many hundreds of times, using a steady-state version of the model can help to keep run times short. Care must be taken to ensure that the parameter distributions produced through these techniques are conceptually defensible, and they must be checked against the conceptual model and modified where necessary. Simulation of extreme conditions such as floods and droughts can be problematic for Chalk aquifers. Previous studies have shown that the Chalk can be resistant to drought, with higher flows recorded in rivers than can be accounted for from releases from fissure storage alone. An approach has been developed that simulates a weak hydraulic connection between fissures and a proportion of matrix storage within the Chalk, providing a delayed yield of significant additional volumes of water during droughts. The application of this approach results in a significant improvement in the simulation of extreme events.
A rapid model for estimating the depletion in river flows due to groundwater abstraction
Authors: Hulme P. J. , Jackson C. R. , Atkins J. K. , Hughes A. G. , Mansour M. M. , Seymour K. J. , Wilson K. J.
Published: April 2012

The Environment Agency of England and Wales uses its calibrated regional models to estimate the reduction in river flows resulting from proposed groundwater abstractions. Where there is no regional model, analytical equations can produce quick initial estimates of river flow depletion. However, users often want more confidence in their estimates by representing more faithfully their understanding of the real river–aquifer system. This paper shows that, when using a numerical model designed to predict river flow depletion, it is important to include adjacent catchments and intermittent streams and less important to include river elevations and variations in transmissivity with groundwater head. Recharge does not usually need to be included unless part of the river becomes disconnected or dry. Therefore, for rivers where stream length is constant and transmissivity variations are small, it is valid to use a ‘no-recharge’ depletion model, which can be built quickly (within a month). A case study on the River Leith in NW England illustrates the use of such a model to assess the ecological impact of two groundwater abstraction licences under the European Union Habitats Directive.
Simulation of a water transfer tunnel at catchment scale in the Permo-Triassic Sandstone aquifer, UK
Authors: Daily P. J. J. , Riley J. J. , Shepley M. G. , Buss S. R.
Published: April 2012

The Lichfield Permo-Triassic Sandstone aquifer is a strategic groundwater resource for the UK West Midlands. However, the flows of a number of streams have been heavily affected by abstraction. The catchment of one of these, the Leamonsley Brook, is under-drained by the Hanch Tunnel, a 5 km-long water transfer tunnel that is more than 150 years old. The Hanch Tunnel was excavated below the water-table for its entire length and is only partly lined. Regional-scale simulation of the aquifer was undertaken using a version of the USGS MODBRNCH code, which had been previously adapted to enable simulation of both open channel and pressurized pipe flow systems (the ‘Adit Code’). This paper reports on the simulation of the Hanch Tunnel, with an emphasis on the representation of this tunnel, and its effects on the groundwater flow in the Leamonsley Brook catchment. Critical aspects to consider when implementing the Adit Code are identified and discussed. The value of the application of the Adit Code for options appraisal to resolve the low-flow conditions of the Leamonsley Brook is explored.
Using and refining an existing regional groundwater model to assess the impacts of an abstraction on a nearby wetland
Authors: Gellatly S. C. , Raynor M. E. , Green C. J. E. , Neve P. S.
Published: April 2012

An existing regional groundwater model was refined, updated and recalibrated to assess the local impacts that a resumption of groundwater abstraction could have on water levels in a nearby wetland. A number of approaches to refining the regional model were tested, and the impact of reducing the model domain on simulated heads was evaluated. Reducing the model domain was found to be unviable due to the absence of suitable boundary conditions; the regional model domain was maintained, the grid was refined locally, and boundary conditions were relocated to more accurately reflect the study area. Two layers were added to represent the drift deposits, and the recharge model was modified to better match observed heads in the drift. The refined model was recalibrated to both long-term historical data and recent pumping test data. A predictive model was set up to run for 20 years to assess the impact of different pumping regimes, thus enabling the model to be used as a decision support tool during the licence review process.
The role of numerical modelling in understanding groundwater flow in Scottish alluvial aquifers
Authors: Mansour M. M. , Hughes A. G. , Robins N. S. , Ball D. , Okoronkwo C.
Published: April 2012

Groundwater in Scotland has been, until recently, an under-rated resource given the abundance of surface water resources. In the last decade, a number of new abstractions have been developed and existing ones enhanced. Implementing groundwater abstraction licensing through the Scottish Water Environment (Controlled Activities) Regulations (2005) has accelerated the need to understand such schemes. Simulating the groundwater systems, which are generally small in area, with an immature understanding and where subsurface data are often sparse, is a challenge. This challenge is amplified when groundwater abstraction is proposed from previously unexploited gravel valley deposits in close proximity to large rivers. Examples of recent work undertaken for Scottish Water illustrate the important role that groundwater models have in testing and refining conceptual understanding as well as convincing regulators of the suitability of the groundwater abstraction.
Influence of Electrolyte Composition on the Behavior of Magnesium at High Anodic Potentials
Authors: Borba Jefferson P. , Poznyak Alexander A. , Knörnschild Gerhard
Published: April 2012

Potentiodynamic curves were measured in electrolytes of 0.2Mol/L NaOH with the addition of compounds used in conventional and in recently developed anodizing baths. The curves showed as a characteristic behavior passivity breakdown at about +3V, high current densities of magnesium dissolution, followed by secondary passivation and breakdown of the anodic film at high potentials. The compounds were characterized according to their influence on the potential and the critical current density for secondary passivation, the passive current density and the breakdown potential of the anodic film. Compared with 0.2Mol/L NaOH, the addition of fluoride, phosphate, stannate and ethanol lowered the critical current density for secondary passivation. Al(OH)3 and silicate showed no effect on the critical current density. No secondary passivation occurred in the presence of permanganate, while in the presence of silicate no sharp active-passive transition was found.
Modified Hybrid Coatings for Anticorrosion Protection of Aluminum Alloy 2024-T3
Authors: Vasconcelos Bruno M. , Hernández Rocio D. , Magnani Marina , Recloux Isaline , Olivier Marie-Georges , De Melo Hercilio G.
Published: April 2012

Aluminum alloy 2024-T3 is an important material used in the aerospace industry. However due to its complex microstructure this alloy is highly prone to localized corrosion. The first step in the protection protocol of these alloys is either anodization or the application of a conversion coating. Nowadays standard industrial procedures employ carcinogenic chromate ions to produce the conversion coating. Hybrid organic-inorganic coatings are promising environmentally compliant chemicals that are being investigated as potential substitutes for chromates. In the present study we report some results on the anticorrosion behavior of a Ce modified TEOS-GPTMS hybrid coating as an anticorrosion system applied to Al alloy 2024-T3. The electrochemical investigation was carried out by means of electrochemical impedance spectroscopy (EIS) and anodic polarization curves, and SEM-EDS used to evaluate the coating microstructure of the coatings.
Using the Electrochemical Impedance Spectroscopy to Characterize Carbon Steel in Biodiesel Medium
Authors: Akita Adriano H. , Fugivara Cecílio S. , Aoki Idalina V. , Benedetti Assis V.
Published: April 2012

Electrochemical impedance spectroscopy measurements using two carbon steel electrodes in soybean biodiesel medium, produced by methylic route, were performed in an electrochemical cell that allows positioning the two electrodes face-to-face. To retain the biodiesel between the electrodes and prevent its leakage a porous membrane soaked in biodiesel was used. The amplitude of the AC potential and the area of the electrodes were varied. The linearity between disturbance and response signals was observed for tests when the amplitude of the AC potential was lower than 1500 mV (rms). The electrical resistance of biodiesel dominates the global response and carbon steel presents low corrosion, which is observed only at low frequency, and was confirmed by chemical tests performed in the membrane. In conclusion the electrical resistance of biodiesel can be estimated using electrochemical impedance spectroscopy with two electrodes set up.
Experimental Design in the Study of Galvanic Corrosion: A Resource for Complex Electrochemical Environment
Authors: Cruz Maria Clara P. , Soares Cleide Mara F. , Figueiredo Renan T. , Cavalcanti Eliane B. , Souza R. E. , Araújo Paulo Mário M.
Published: April 2012

The behavior of galvanic corrosion between carbon steel and CuAlBe with Shape Memory Effect was investigated using the technique of Zero Resistance Amperometry (ZRA), in an electrolytic environment that simulates the water produced from mature oil fields. For this purpose, we used a fractional factorial design 26-2 + 6 central points with the following variables: Cl-, SO4=, S =, HCO3-, ratio of anodic area to cathodic area (1:1, 1:1/2 , 1:1/4) and temperature (25, 35 and 45 °C), where the dependent variable was the galvanic current density measured after 12 h. The results on the response surfaces show evidence of passivation and depassivation, as seen in the nonlinear shape observed in the figures. Therefore, using an experimental design it is possible to study complex chemical equilibrium.
Electrochemical Degradation of Methyl Paraben Using a Boron-Doped Diamond Anode
Authors: Steter Juliana R. , Dionísio Dawany , Rocha Robson S. , Miwa Douglas W. , Lanza Marcos R. , Jesus Motheo Artur
Published: April 2012

The electrochemical oxidation of aqueous solution containing methyl paraben (100 mg L-1) in Na2SO4 (0.05 mol L-1) was performed in a one compartment cell using a BDD (boron-doped diamond) anode. Electrolyses were carried out at different current densities (25 at 100 mA cm-2) and the results indicated that the process is supported by mass transport. The kinetic analysis based on methyl paraben concentration monitored during electrolysis shows that the concentration decay has a pseudo first-order behavior.
Electrochemical Decolourization Process of Textile Dye in the Presence of NaCl at BDD and Ti/Pt Electrode
Authors: Bezerra Rocha Jéssica H. , Barbosa Ferreira Maiara , Suely Fernandes Nedja , Martínez-Huitle Carlos A.
Published: April 2012

Aim of this work is to discuss the electrochemical colour removal process of a textile dye (Yellow Novacron (YN)) dissolved in synthetic wastewaters, analyzing the influence of NaCl. Experiments were carried out at boron-doped diamond (BDD) and Platinum supported in Titanium (Ti/Pt). The process is significantly accelerated by the presence of a halogen salt in solution; interestingly, the mediated process does not depend on applied current density; but it depends on NaCl concentration. Finally, the parameters of removal efficiency and energy consumption for the electrochemical decolourisation process were estimated.
Synthesis and Electrochemical Characterization of the Pt-based Catalysts for the Glycerol Oxidation
Authors: Caliman Cristiano C. , Santos Deise M. , Ribeiro Josimar
Published: April 2012

Binary, ternary and quaternary electrocatalysts of type C/Pt-based were prepared by the Pechini method. The physical-chemical characterization and electrochemical investigation of the electrocatalysts were performed by different techniques: X-ray diffraction, cyclic voltammetry and chronoamperometry. The XRD results show that the electrocatalysts are mainly formed by Pt metal structure with face-centered cubic crystalline. The electrocatalysts were evaluated in the absence and presence of glycerol in sulfuric acid medium. The ternary electrocatalyst composition in which platinum is greater than 70 mol% showed the highest values of current density during the chronoamperometry studies. The catalyst C/Pt70Ru20Ni10 showed the most significant peaks of oxidation of glycerol and its intermediates products in VC: in the positive-going scan and in the negative-going scan.
The Effect of pH on Electro-Oxidation of Phenolic Compounds at Boron-Doped Nanocrystalline Diamond Films (BDND)
Authors: Santos Marta , Azevedo Adriana F. , Souza Fernando A. , Baldan Mauricio R. , Ferreira Neidenei G.
Published: April 2012

The surface properties of boron-doped nanocrystalline diamond (BDND) films were investigated in regard to their electrochemical response to phenol, 4-chlorophenol and 4-nitrophenol. The films were produced using Hot Filament CVD technique on Si substrate with a gas mixture of CH4/H2/Ar. The morphology and quality of the BDND electrode were characterized by scanning electron microscopy and by Raman scattering spectroscopy. The BDND surface pre-treatment was carried out to evaluate the phenolic compounds detection efficiency induced by anodic polarization (AP) followed by cathodic polarization (CP) polarization in 1 mmol L−1 of these compounds in different pH range from 1 to 13.5. The use of cyclic and linear voltammetry with the BDND electrodes for the detection of these phenolics compounds is described.
Development of New Systems of Nano-Disperse Pt-(2%Pt-Ce0.9W0.1O2)/C Electrocatalysts Tolerant to Carbon Monoxide (CO) for PEMFC Anodes
Authors: Nandenha Júlio , Isidoro R. A. , Dresch M. A. , Fernandes V. C. , Aricó Eliana M. , Santiago E. I. , Rothenberg G. , Oliveira W. S. , Linardi Marcelo
Published: April 2012

The nanophase material (powder) of Ce0.9W0.1O2 was synthesized via coprecipitation of oxalates of cerium (IV) and tungsten cations. Pt-Ce0.9W0.1O2 (2 wt% Pt) was prepared by an alcohol-reduction process using H2PtCl6.6H2O as source of Pt, Ce0.9W0.1O2 as support and ethylene glycol as solvent and reducing agent. Pt-Ce0.9W0.1O2 was physically mixed with commercial Pt/C E-TEK (20 w% Pt) to produce the Pt-(2%Pt-Ce0.9W0.1O2)/C electrocatalyst. The prepared electrocatalysts were characterized by energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and CO stripping. The performances of Pt/C E-TEK and Pt-(2%Pt-Ce0.9W0.1O2)/C electrocatalysts were tested in single fuel cell fed with a mixture H2/CO (100 ppm of CO). The results showed that the mixture of 2%Pt-Ce0.9W0.1O2 and Pt/C E-TEK increases the CO tolerance in a single fuel cell operating at 85 ºC compared with Pt/C E-TEK.
Electrochemical and Morphology Study of the BDD/Ti Electrodes with Different Doping Levels
Authors: Alves Suellen A. , Migliorini Fernanda L. , Baldan Mauricio R. , Ferreira Neidenei G. , Lanza Marcos R.
Published: April 2012

Boron-doped diamond (BDD) electrodes have shown characteristics that differ from other conventional electrodes, and that make them an excellent electrode in the electroanalysis, in the electrosynthesis and also in the treatment of wastewater with organic compounds. In this work, two different electrodes doped with (2,000 and 15,000 ppm) were characterized by Raman Spectroscopy and by Scanning electron Microscopy (SEM). In addition, they were characterized electrochemically by cyclic voltammetry. The electroactive area was estimated according to Cottrell's equation before and after the anodic and the cathodic treatment. From the results, it was observed that the electrodes have a similar behavior in the morphology and in the homogeneity of the films. The large potential window was confirmed for both electrodes (2.5 V vs Ag/AgCl) and for the less doped electrode was obtained a larger area without any treatment while for the more doped electrode, the major area was obtained after the cathodic treatment.
Carbon Paste Electrode Modified with Ascorbic Acid and Carbon Nanotubes for Determination Copper in Sugar Cane Spirit
Authors: Teixeira Meryene C. , Tavares E. F. , Saczk Adelir A. , Okumura Leonardo L. , Cardoso Maria G. , Oliveira Marcelo F. , Magriotis Zuy M.
Published: April 2012

This work has been carried out in order to determine the copper content in sugar cane spirit samples from the south of Minas Gerais, using a carbon paste electrode modified with ascorbic acid and carbon nanotubes using the square wave voltammetry technique. The following parameters were studied: Ed (deposit potencial). Td (deposit time), f (frequency), A (amplitude) and ΔEs (increment scanning). The analytical curve was built in an interval from 0.5 to 12 mg L-1 and a coefficient of linear correlation of 0.997 Three sugar cane spirit samples were analysed, which presented copper content ranging from 0.29 to 1.59 mg L-1.
Mechanism of Electro-Oxidation of Metamizole Using Ciclic Voltammetry at a Glassy Carbon Electrode
Authors: Bacil Raphael P. , Buoro Rafael M. , Da-Silva Robson P. , Medinas Daniel B. , Lima Antonio W. , Serrano Silvia H.
Published: April 2012

Cyclic Voltammetry at glassy carbon electrode was applied to study the electro-oxidation of Metamizole, a pro-drug largely used in many countries as analgesic which the therapeutic properties are attributed to its hydrolyzed form. Metamizole presents three oxidation processes in aqueous (Britton Robinson Buffer) and DMF media. The first process was characterized as reversible in the last medium. The differentiation between the process associated with the Metamizole and its respective hydrolyzed form the MAA, was investigated and allowed the proposition of a mechanism for the Metamizole electro-oxidation.
Electrochemical Determination of Antimalarial Drug Amodiaquine in Maternal Milk Using a Hemin-Based Electrode
Authors: Valente Cristiane O. , Garcia Carlos Alexandre B. , Alves José Patrocínio H. , Zanoni Maria Valnice B. , Stradiotto Nelson R. , Arguelho Maria Lara P.
Published: April 2012

Voltammetric analysis of amodiaquine using a hemin biosensor revealed a well-defined peak at 0.14 V (vs. Ag/AgCl), corresponding to the oxidation of amodiaquine at pH 7.0. The electrodic behavior indicated that the oxidation process was irreversible, and that it was controlled by diffusion. In addition to advantages such as high selectivity and sensitivity, the method developed could be used for the analysis of breast milk containing amodiaquine without any need for prior sample treatment, an important consideration in routine analysis laboratories. Measurements of the drug contained in breast milk were used to validate the technique. The detection limit for standard solutions was 3.30 mg L-1, and the quantification limit was 11.0 mg L-1.
Determination Of Procymidone in Apple by Square-Wave Voltammetry
Authors: FulgÊncio Ana Carolina C. , Okumura Leonardo L.
Published: April 2012

A low cost electrochemical method was developed for the determination of trace-level of procymidone based on the properties of glassy carbon electrode (GCE). The electrochemical behavior of procymidone studied by cyclic voltammetry (CV) suggests that its oxidation occurs via a one irreversible electron transfer vs. Ag|AgCl, KCl 3 M reference electrode. The anodic peak potential for procymidone oxidation at GCE is about +1.38 V in a supporting electrolyte solution composed of NaOH 0.5 mol L-1. A combination of GCE with square-wave voltammetric analysis resulted in a sensitive and selective electrochemical method for determination of procymidone pesticide in apple.
Preparation of PtSn/C Electrocatalyst by Successive Reduction for Ethanol Electro-Oxidation
Authors: Ribeiro Vilmaria A. , Neto Almir O. , Linardi Marcelo , Spinacé Estevam V.
Published: April 2012

PtSn/C electrocatalyst was prepared in two steps: i) initially SnCl2.2H2O was reduced on the carbon support using sodium borohydride as reducing agent. At the second step the obtained Sn/C was used as support and H2PtCl6.6H2O was reduced by an alcohol-reduction process. The obtained PtSn/C electrocatalyst was characterized by X-ray diffraction and cyclic voltammetry. The electro-oxidation of ethanol was studied by chronoamperometry. The commercial electrocatalyst PtSn/C BASF (PtSn alloy) was used for comparison. The results showed that the PtSn/C electrocatalyst prepared by successive reduction was more active for ethanol electro-oxidation than the commercial PtSn/C BASF electrocatalyst.
Permanence in Multispecies Nonautonomous Lotka‐Volterra Competitive Systems with Delays and Impulses
Authors: Feng Xiaomei , Zhang Fengqin , Wang Kai , Li Xiaoxia
Published: April 2012

This paper studies multispecies nonautonomous Lotka‐Volterra
competitive systems with delays and fixed‐time impulsive effects. The sufficient conditions of integrable form on the permanence of species are established.
Comparison of Provision of Stroke Care in Younger and Older Patients: Findings from the South London Stroke Register
Authors: Crichton Siobhan L. , Wolfe Charles D. A. , Rudd Anthony G. , McKevitt Christopher
Published: April 2012

Background. Evidence-based stroke care should be available to all patients. However, evidence exists of inequalities according to age. This study compared access to care for younger adults to that for over 65s.Methods. Using population-based data from 4229 patients with first-ever stroke between 1995 and 2010, associations between age and 21 care indicators were investigated using multivariable logistic regression.Results. Age was not associated with stroke unit admission for ischaemic stroke (P=0.666). Younger PICH patients were least likely to be admitted to stroke units (P=0.001), instead treated on neurosurgical or ICU wards. Younger age was also associated with admission to neurosurgery or ICU after SAH (P=0.006), increased occupational or physiotherapy at 1 year (P=0.043), and contact with a GP 3 months after stroke (P<0.001).Conclusion. Younger patients have equal or greater access to evidence-based care. However, there is a need to ensure that services meet the needs of this group.
Analyzing the Dynamics of a Rumor Transmission Model with Incubation
Authors: Huo Liang′an , Huang Peiqing , Guo Chun-xiang
Published: April 2012

This paper considers a rumor transmission model with incubation that incorporates constant recruitment and has infectious force in the latent period and infected period. By carrying out a global analysis of the model and studying the stability of the rumor‐free equilibrium and the rumor‐endemic equilibrium, we use the geometric approach for ordinary differential equations which is based on the use of higher‐order generalization of Bendixson’s criterion. It shows that either the number of rumor infective individuals tends to zero as time evolves or the rumor persists. We prove that the transcritical bifurcation occurs at R0 crosses the bifurcation threshold R0 = 1 by projecting the flow onto the extended center manifold. Since the rumor endemic level at the equilibrium is a continuous function of R0, as a consequence for successful eradication of the rumor, one should simply reduce R0 continuously below the threshold value 1. Finally, the obtained results are numerically validated and then discussed from both the mathematical and the sociological perspectives.
Atypical Febrile Seizures, Mesial Temporal Lobe Epilepsy, and Dual Pathology
Authors: Sanon Nathalie T. , Desgent Sébastien , Carmant Lionel
Published: April 2012

Febrile seizures occurring in the neonatal period, especially when prolonged, are thought to be involved in the later development of mesial temporal lobe epilepsy (mTLE) in children. The presence of an often undetected, underlying cortical malformation has also been reported to be implicated in the epileptogenesis process following febrile seizures. This paper highlights some of the various animal models of febrile seizures and of cortical malformation and portrays a two-hit model that efficiently mimics these two insults and leads to spontaneous recurrent seizures in adult rats. Potential mechanisms are further proposed to explain how these two insults may each, or together, contribute to network hyperexcitability and epileptogenesis. Finally the clinical relevance of the two-hit model is briefly discussed in light of a therapeutic and preventive approach to mTLE.
Aquatic Exercise Is Effective in Improving Exercise Performance in Patients with Heart Failure and Type 2 Diabetes Mellitus
Authors: Åsa Cider , Maria Schaufelberger , Katharina Stibrant Sunnerhagen , Bert Andersson
Published: April 2012

Background. Peak oxygen uptake (VO2peak) and muscle function are more decreased in patients with a combination of chronic heart failure (CHF) and type 2 diabetes mellitus (2DM) compared to patients with only one of the conditions. Further, patients with 2DM have peripheral complications that hamper many types of conventional exercises.Aim. To evaluate the efficacy and applicability of eight-week aquatic exercise in patients with the combination of CHF and 2DM.Methods. Twenty patients (four women) with both CHF and 2DM (age67.4±7.1, NYHA II-III) were randomly assigned to either aquatic exercise or a control group. The patients exercised for 45 minutes 3 times/week in 33–34°C, swimming pool.Results. The training programme was well tolerated. Work rate (+11.7±6.6versus−6.4±8.1 watt,P<0.001) andVO2peak(+2.1±0.8versus−0.9±1.4mL⋅kg−1⋅min−1,P<0.001) and walking capacity (P=0.01) increased significantly in the training group. Muscle function was also significantly improved and Hba1c decreased significantly (P<0.01) during training, while fasting glucose, insulin, c-peptide, and lipids were unchanged . Training also increased vitality measured by SF-36 significantly (P=0.05).Conclusion. Aquatic exercise could be used to improve exercise capacity and muscle function in patients with the combination of CHF and 2DM.
Dielectric Relaxation Phenomena of Polylactic Acid with -Crystalline Chitin
Authors: Shinyama Katsuyoshi , Oi Toru , Fujita Shigetaka
Published: April 2012

-crystalline chitin was added to polylactic acid (PLA), and this PLA was then heat-treated at for one minute. The crystallinity of the heat-treated PLA increased to more than 40%, and its crystallization speed also increased significantly. The temperature dependency of these materials’ relative permittivity () and relative dielectric loss factor () was also examined. The dielectric absorption peak value in curve of the PLA to which chitin was added and was smaller than that of PLA without chitin. Additionally, the Havriliak-Negami relaxation function was used to produce approximation curves for the frequency dependency of and of chitin with PLA added at . As a result, the relaxation strength of the chitin with PLA added was smaller than that of the PLA without chitin, and the relaxation time of the chitin with PLA added was approximately 2.5 times larger than that of the PLA without chitin.
Separation of m/p‐Aminoacetophenone Using Hydrotropy
Authors: Dhinakaran M. , Morais Antony Bertie , Gandhi N. Nagendra
Published: April 2012

The aqueous solubilities of m/p‐aminoacetophenone in different concentrations (0‐3.0 mol/L) of hydrotropes such as diethyl nicotinamide, sodium pseudocumene sulfonate and sodium thiocyanate solutions at different system temperatures (303K to 333K) were studied. The percentage extraction (%E) of m‐ aminoacetophenone from m/p‐aminoacetophenone mixture increases with increase in hydrotrope concentration. A Minimum Hydrotrope Concentration (MHC) in the aqueous phase was required to initiate the significance of the %E of m‐aminoacetophenone. Percentage extraction (%E) is the ratio of moles of m‐aminoacetophenone extracted in presence and absence of a hydrotrope. The sensitivity and feasibility of the proposed process are examined by carrying out solubilization and equilibrium precipitation experiments with the mixtures of various compositions. The effectiveness of hydrotropes was measured in terms of Setschenow constant Ks. The extraction data are also fitted in a polynomial equation as the function of hydrotrope concentration. The solubilized material can be recovered by dilution with water.
Evaluation of Patient Satisfaction of an Outpatient Colonoscopy Service in an Asian Tertiary Care Hospital
Authors: Chan Wah-Kheong , Goh Khean-Lee
Published: April 2012

Aim. To evaluate patient satisfaction towards an outpatient colonoscopy service and analyze areas of dissatisfaction for potential improvement.Method. Consecutive patients attending the outpatient diagnostic colonoscopy service in University of Malaya Medical Centre between 1st February and 31th July 2010 were interviewed using a questionnaire modified from the modified Group Health Association of America-9 (mGHAA-9) questionnaire. Favorable/unfavorable responses to each question, contribution of each question to unfavorable responses, and effect of waiting times on favorable/unfavorable response rates were analyzed.Results. Interview was carried out on 426 patients (52.1% men). Mean age ± standard deviation was61.3±12.9years old. Mean waiting times for colonoscopy appointment and on colonoscopy day were3.8±2.7months and1.1±0.8hours, respectively. The main factors that contributed to unfavorable responses were bowel preparation followed by waiting times for colonoscopy appointment and on colonoscopy day (32.3%, 27.5%, and 19.6%, resp.). Favorable responses diminished to undesirable levels when waiting times for colonoscopy appointment and on colonoscopy day exceeded 1 month and 1 hour, respectively.Conclusion. Bowel preparation and waiting times were main factors for patient dissatisfaction. Waiting times for colonoscopy appointment and on colonoscopy day should not exceed 1 month and 1 hour, respectively, to maintain acceptable levels of patient satisfaction.
Building the Clinical Bridge: An Australian Success
Authors: Wallis Marianne , Chaboyer Wendy
Published: April 2012

Nursing effectiveness science includes primary, secondary, and translational, clinically focused research activities which aim to improve patient or client outcomes. It is imperative, for the successful conduct of a program of nursing effectiveness science, that a clinical bridge is established between academic and healthcare service facilities. An Australian example of the development of a robust clinical bridge through the use of jointly funded positions at the professorial level is outlined. In addition, an analysis of the practical application of Lewin’s model of change management and the contribution of both servant and transformational leadership styles to the bridge building process is provided.
Soil Health Management under Hill Agroecosystem of North East India
Authors: Saha R. , Chaudhary R. S. , Somasundaram J.
Published: April 2012

The deterioration of soil quality/health is the combined result of soil fertility, biological degradation (decline of organic matter, biomass C, decrease in activity and diversity of soil fauna), increase in erodibility, acidity, and salinity, and exposure of compact subsoil of poor physicochemical properties. Northeast India is characterized by high soil acidity/Al+3toxicity, heavy soil, and carbon loss, severe water scarcity during most parts of year though it is known as high rainfall area. The extent of soil and nutrient transfer, causing environmental degradation in North eastern India, has been estimated to be about 601 million tones of soil, and 685.8, 99.8, 511.1, 22.6, 14.0, 57.1, and 43.0 thousand tones of N, P, K, Mn, Zn, Ca, and Mg, respectively. Excessive deforestation coupled with shifting cultivation practices have resulted in tremendous soil loss (200 t/ha/yr), poor soil physical health in this region. Studies on soil erodibility characteristics under various land use systems in Northeastern Hill (NEH) Region depicted that shifting cultivation had the highest erosion ratio (12.46) and soil loss (30.2–170.2 t/ha/yr), followed by conventional agriculture system (10.42 and 5.10–68.20 t/ha/yr, resp.). The challenge before us is to maintain equilibrium between resources and their use to have a stable ecosystem. Agroforestry systems like agri-horti-silvi-pastoral system performed better over shifting cultivation in terms of improvement in soil organic carbon; SOC (44.8%), mean weight diameter; MWD (29.4%), dispersion ratio (52.9%), soil loss (99.3%), soil erosion ratio (45.9%), andin-situsoil moisture conservation (20.6%) under the high rainfall, moderate to steep slopes, and shallow soil depth conditions. Multipurpose trees (MPTs) also played an important role on soil rejuvenation.Michelia oblongais reported to be a better choice as bioameliorant for these soils as continuous leaf litter and root exudates improved soil physical behaviour and SOC considerably. Considering the present level of resource degradation, some resource conservation techniques like zero tillage/minimum tillage, hedge crop, mulching, cover crop need due attention for building up of organic matter status for sustaining soil health.
Nano‐Catalytic Ozonation of 4‐Nitrochlorobenzene in Aqueous Solutions
Authors: Tabatabaei S. M. , Mehrizad A. , Gharbani P.
Published: April 2012

In this paper, efficiency of nano‐ZnO particles on catalytic ozonation of 4‐nitrochlorobenzene (4NCB) using semi‐batch reactor has been studied at various pHs. During the catalytic ozonation, TOC and concentration of nitrate ions was monitored. Results indicate that degradation of 4NCB was improved by combination of nano‐ZnO with ozone. The effect of ZnO particle size and pH are also examined. According to the results, concentration of 4NCB decreased with increasing of particle size from nanosized to microsized and pH from 3.0 to 9.0. Based on the results, it suggests radical hydroxyl does not affect on the degradation of 4NCB in catalytic ozonation, but the surface of catalyst plays main role. Kinetic studies showed degradation of 4NCB followed pseudo‐first‐order kinetic and maximum degradation rate was observed at pH=3.
Structural and Electrical Conductivity Properties of a Newly Synthesized 3‐Methoxybenzylammonium Cation Diphosphate
Authors: Elboulali A. , Akriche S. , Rzaigui M. , Al-Deyab S. S.
Published: April 2012

The structure of the newly synthesized material, [3‐(CH3O)C6H4CH2NH3]2H2P2O7 can be described as inorganic layers (H2P2O72-)n stacked perpendicular to the c‐axis at z = 0 and z = 1/2 interleaved with organic cations [3‐(CH3O)C6H4CH2NH3]+. The connection of the independent entities are assured by a set of N—H…O and C—H…O H‐bonds in addition to electrostatic and Van der Waals interactions, generating a non‐centrosymetric three‐dimensional network. On the basis of electrical conductivity measurements, it was found that, at higher temperature conductivity increases linearly, showing medium conducting behaviour of the organic diphosphate salt with values lying in the range of σ= 0.69 10−4 Ω−1cm−1 at 328 K to 2.66 10−4 Ω−1cm−1 at 405 K and activation energy of Ea = 0.23 eV. Its characterization by IR absorption spectroscopy is described too.
An Efficient and Green Procedure for the Synthesis of 2,4,6‐Triarylpyridines Using PPA‐SiO2 as a Reusable Heterogeneous Catalyst Under Solvent‐Free Conditions
Authors: Davoodnia Abolghasem , Razavi Bahareh , Tavakoli-Hoseini Niloofar
Published: April 2012

Silica gel‐supported polyphosphoric acid (PPA‐SiO2) was found to be highly efficient, eco‐friendly and recyclable heterogeneous catalyst for the synthesis of 2,4,6‐triarylpyridines through one‐pot three‐component reaction of acetophenone, aryl aldehydes, and ammonium acetate under solvent‐free conditions. This method has several advantages, such as simple procedure with an easy work‐up, short reaction times, and high yields. Furthermore, the catalyst could be recycled after a simple work‐up, and used at least three times without substantial reduction in its catalytic activity.
Improvement of Aspergillus niger for Sodium Gluconate Synthesis by UV Mutation Method
Authors: Prabu Rajagopalan , Chand Thomas , Raksha Sunhare
Published: April 2012

The sodium gluconate synthesis pathway was improved in Aspergillus niger by random mutation method. A. niger was mutated with Ultraviolet (UV) radiation and the alteration of cell bound enzymes activity of gluconic acid synthesis pathway and sodium gluconate synthesis were evaluated. The improved mutants (A. niger UV‐112) was capable of producing sodium gluconate up to final concentrations of 60 g/L in batch fermentation, which was 3.0 fold higher than the parent strain. It have been observed that the changes in activities of cell bound enzymes related for gluconic acid pathway such as glucose dehydrogenase and glucose oxidase and it were significantly higher than the parent strain. The mutant A. niger strain and the simple method used to decrease the production cost and development of fermentation process for industrial production of gluconic acid or its salt.
Synthesis and Evaluation of Some Coumarin Based Schiff′s Bases as Potential Antimicrobial Agents′
Authors: Bansode Vishakha , Deodhar Meenakshi N.
Published: April 2012

A series of the title compounds 3‐(4‐(4, 5‐dihydro‐5‐(substituted phenyl)‐1H‐3‐pyrazolyl) phenylimino) methyl)‐4‐chloro‐2H‐chromen‐2‐one 5(a‐g) have been synthesized. These compounds were characterized on the basis of their spectral (IR, 1H NMR) data and evaluated for antimicrobial activity in vitro against gram positive bacteria, gram negative bacteria and fungi. The compound (5b) was found to be the most active with MIC of 20 µg/ml against all the tested organisms.
Synthesis of 1,5‐Diaryl‐1,4‐pentadien‐3‐one Amidinohydrazone Hydrochloride Under Ultrasound Irradiation
Authors: Du Chao , Li Ji Tai
Published: April 2012

Synthesis of 1,5‐diaryl‐1,4‐pentadien‐3‐one amidinohydrazone hydrochloride via the condensation of 1,5‐diaryl‐1,4‐pentadien‐3‐one and aminoguanidine hydrochloride catalyzed by hydrochloric acid was carried out in 80‐94% yield at 35‐37°C within 1.5 h under ultrasound irradiation. Compared to the classical method, the advantages of this method are milder conditions, shorter reaction time and higher yield.
Synthesis, Spectral Characterization, Molecular Modeling, and Antimicrobial Studies of Cu(II), Ni(II), Co(II), Mn(II), and Zn(II) Complexes of ONO Schiff Base
Authors: Mendu Padmaja , Pragathi J. , Anupama B. , Kumari C. Gyana
Published: April 2012

A series of Cu(II), Ni(II), Co(II), Mn(II), and Zn(II) complexes have been synthesized from the schiff base ligand L. The schiff base ligand [(4‐oxo‐4H‐chromen‐3‐yl) methylene] benzohydrazide (L) has been synthesized by the reaction between chromone‐3‐carbaldehyde and benzoyl hydrazine. The nature of bonding and geometry of the transition metal complexes as well as schiff base ligand L have been deduced from elemental analysis, FT‐IR, UV‐Vis, 1HNMR, ESR spectral studies, mass, thermal (TGA and DTA) analysis, magnetic susceptibility, and molar conductance measurements. Cu(II), Ni(II), Co(II), and Mn(II) metal ions are forming 1:2 (M:L) complexes, Zn(II) is forming 1:1 (M:L) complex. Based on elemental, conductance and spectral studies, six‐coordinated geometry was assigned for Cu(II), Ni(II), Co(II), Mn(II), and Zn(II) complexes. The complexes are 1:2 electrolytes in DMSO except zinc complex, which is neutral in DMSO. The ligand L acts as tridentate and coordinates through nitrogen atom of azomethine group, oxygen atom of keto group of γ‐pyrone ring and oxygen atom of hydrazoic group of benzoyl hydrazine. The 3D molecular modeling and energies of all the compounds are furnished. The biological activity of the ligand and its complexes have been studied on the four bacteria E. coli, Edwardella, Pseudomonas, and B. subtilis and two fungi pencillium and tricoderma by well disc and fusion method and found that the metal chelates are more active than the free schiff base ligand.
Screening and Isolation of Associated Bioactive Microorganisms from Fasciospongia cavernosa from of Visakhapatnam Coast, Bay of Bengal
Authors: Kumar P. Shamsher , Krishna E. Radha , Sujatha P. , Kumar B. Veerendra
Published: April 2012

Nature, especially the marine environment, provides the most effective drugs used in human therapy. Among the metazoans, the marine sponges produce the most potent and highly selective bioactive secondary metabolites. These animals (or their associated symbiotic microorganisms) synthesize secondary metabolites whose activity and selectivity has developed during their long evolutionary history. During the course of exploitation of these resources two marine sponges, Fasciospongia cavernosa doc var.brown (dark brown) Fasciospongia cavernosa doc var.yellow (yellow) collected from the visakhapatnam coast of Bay of Bengal were investigated in order to assess the potential of these microorganisms for the production of antimicrobial compounds. The aqueous and organic extracts of both the sponges showed broad spectrum antibiotic activity. In this study a total of 178 microorganisms were isolated from different parts of two sponges and most of them from middle part of the sponge. The isolates were investigated in order to assess the potential of these microorganisms for the production of antimicrobial compounds. Testing for antimicrobial activities were performed against Gram‐positive (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus) Gram‐negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Proteus vulgaris), fungi (Candida albicans, Aspergillus niger) and 10 pathogenic organisms. Resulting mean diameter of inhibition zones revealed isolates B4 & B6 were the most potent of all the isolates. The present study has revealed the presence of high numbers of diverse culturable microorganisms associated with the marine sponges from Visakhapatnam Coast of Bay of Bengal as well as their potential to produce bioactive metabolites.