bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced Magnetoelectric Response and Phonon Abnormality of Self-assembled Feather-like CoFe2O4-BaTiO3 Nanostructures
Authors: Deng Yu , Wu Di , Yu Huiqiang , Du Youwei
Published: October 2012

Magnetoelectric (ME) (CoFe2O4)0.3-(BaTiO3)0.7 (CFO-BTO) nanostructures have been synthesized by a combinative using of hydrothermal reaction and polymer-assisted deposition. The feather-like nanostructures have an average diameter of 250nm and lengths up to 5μm, with the single-crystal CFO nanopillars embedded in the BTO matrix. The CFO-BTO nanostructures exhibit good magnetic (Ms=21.0emu/g, Mr=10.4emu/g and Hc=560.7Oe) and ferroelectric properties (Ps=10.5μC/cm2, Pr=5.6μC/cm2), as well as a large ME coefficient of 51.8mV/cmOe. A prominent phonon abnormality has also been detected between 110°C and 140°C. With emphasis on the novel microstructure, the ME response and phonon abnormality of the CFO-BTO nanostructures have been discussed.
Fabrication and Surface Morphology of YBCO Superconducting Thin films on STO Buffered Si Substrates
Authors: Mutlu Zafer , Mutlu Yasar G. , Yilmaz Mucahit , Dogan Oguz , Ozkan Mihrimah , Ozkan Cengiz S.
Published: October 2012

Pulsed Electron Deposition (PED) is an attractive alternative to Pulsed Laser Deposition (PLD) for growing high temperature superconductor thin films because of its relatively low cost. In this study, YBa2Cu3O7-δ(YBCO) thin film has been fabricated on silicon substrates by Pulsed Electron Deposition technique. SrTiO3 (STO) as a buffer layer has been grown between Si substrate and YBCO superconducting layer. The crystalline structures of STO/Si and YBCO/STO/Si films have been investigated by x-ray diffraction (XRD). The surface morphology and microstructure of YBCO/STO/Si thin film have been characterized with atomic force microscope (AFM) and scanning electron microscope (SEM). From the θ-2θ XRD analysis of YBCO thin films, (00l) diffraction peaks are obtained indicating they have a poor c-axis oriented structure. SEM analysis shows that the surfaces of films are crack-free, but they have some particulates. On AFM images, the droplets are clearly observed leading to a roughly surface.
Applications of Oxide Nanomaterials in Nonlinear Optics
Authors: Philip Reji , Sandeep C.S. Suchand , Seema R. , Krishnan Shiji , Chantharasupawong Panit , Kalarikkal Nandakumar , Thomas Jayan
Published: October 2012

Nonlinear optical effects are revealed when strong light fields interact with matter. It has been shown that nanomaterials exhibit properties which are very different from the bulk, and in many cases, the nonlinear optical (NLO) efficiency of nanomaterials is found to be higher in comparison. Recently there has been substantial interest in developing novel NLO media for various applications. Even though several organic as well as inorganic materials have been studied in this connection, only a limited number of NLO reports exist for oxide nanomaterials. Therefore, in this paper we present results of NLO measurements recently conducted in our laboratory in three different oxide nanosystems. It is found that oxide nanomaterials are generally robust, and exhibit good NLO efficiencies, which make them potential candidates for photonic and optoelectronic applications.
Effect of the Type of Solvent and Bi-Stoichiometric Excess on the Purity of Nanocrystalline Bismuth Ferrite Single Phase
Authors: Montes-Albino Gina , Gálvez-Saldaña Marco , Renteria-Beleño Boris , Perales-Pérez Oscar
Published: October 2012

The main challenge associated with the synthesis of pure bismuth ferrite (BFO) is the extremely high stability of parasitic or secondary phase Bi-oxides, which contaminates the single ferrite phase and affects the corresponding functional properties. Therefore, any attempt to determine the optimum synthesis conditions conducive to the inhibition of the formation of those impurity phases becomes indispensable. Accordingly, the present work addresses the systematic evaluation of the type of solvent and synthesis parameters to exclusively produce the BFO structure. Nanocrystalline BFO powders were synthesized after thermal treatment of the solid intermediates formed in ethylene glycol and acetic acid media. The experimental work also considered the effect of the excess of Bi species with respect to the BiFeO3stoichiometry and the annealing of the intermediates at different temperatures. The structure formation was confirmed by XRD analysis and magnetic properties were studied by VSM. X-ray diffraction analyses confirmed that powders exhibiting single phase BFO structure were produced after annealing the intermediate which was formed in acetic acid for one hour at 700°C. The average crystallite size and lattice parameter were calculated to be approximately 40 nm and 5.36 Å, respectively. It was also found that the synthesis under 7% of Bi-stoichiometric excess inhibited the formation of the parasitic phases after annealing the intermediate produced in ethylene glycol medium. The saturation magnetization of the powders annealed at 700°C were 0.15 emu/g and 0.17 emu/g when the BFO intermediates were formed in ethylene glycol and acetic acid media, respectively. The corresponding coercivity values were 6 Oe and 21 Oe.
Epitaxial thin films of ordered double perovskite SrLaVMoO6
Authors: Sanbou Katsutoshi. , Sakuma Keita. , Miyawaki Tetsuya. , Ueda Kenji. , Asano Hidefumi.
Published: October 2012

Epitaxial thin films of SrLaVMoO6 with an ordered double perovskite structure have been grown on (001) and (111) SrTiO3 substrates by magnetron sputtering. The optimized (111) film exhibited a clear (111) diffraction peak, which is a superlattice reflection of double perovskite unite cell, indicating clear B-site ordering. Temperature dependences of resistivity ρ show metallic behavior and transition point at 140~150 K, of which behavior is reminiscent of the electrical properties of materials showing long-range magnetic or antiferromagnetic order. XPS results of the Mo 3d core level spectra are discussed in terms of the B-site ordering and oxygen nonstoichiometry.
Structural, optical and magnetic properties of highly oriented transition metal (Mn/Co/Ni/Cu) doped ZnO thin films prepared by PLD
Authors: Aravind Arun , Jayaraj M.K. , Kumar Mukesh , Chandra Ramesh
Published: October 2012

ZnO doped with transition metal (TM) thin films were grown by pulsed laser deposition. XRD pattern reveals that all the ZnTMO films have c-axis orientation normal to the substrate. The reciprocal space mapping shows that the crystallinity of ZnTMO film deteriorates at higher doping of TM. All the TM doped ZnO films have transmittance greater than 75% in the visible region. The band gap of the ZnTMO thin films shows red shift on doping with Ni and Cu where as blue shift is observed for Co and Mn which increases with TM concentration. The copper doped ZnO thin film shows green PL emission at 542 nm along with the band edge emission at 385 nm. But other TM doping shows only band edge emission (385nm) and its intensity decreases at higher doping percentage. The presence of non-polar E2high and E2lowRaman modes in thin films indicates that ‘TM’ doping do not alter the wurtzite structure of ZnO. The magnetic studies of the TM doped ZnO shows room temperature ferromagnetism
Relaxor Behavior in Ba0.8Sr0.2TiO3/ZrO2 Heterostructured Thin Films
Authors: Sahoo Santosh K. , Bakhru H. , Kumar Sumit , Misra D. , Mohapatra Y. N. , Agrawal D. C.
Published: October 2012

Ba0.8Sr0.2TiO3 (BST) thin films and Ba0.8Sr0.2TiO3/ZrO2 heterostructured thin films have been successfully fabricated on Pt/Ti/SiO2/Si substrates by a sol-gel process. The dielectric properties of these films were measured as a function of temperature in the frequency range of 1 kHz to 1 MHz. It is clearly observed that the dielectric peaks exist and shift to high temperature with the increase of frequency indicating the presence of relaxor-type behavior in the films. Also it is seen that one dielectric peak is observed in single layer BST thin films whereas two dielectric peaks are observed in BST/ZrO2 heterostructured thin films due to the presence of two dielectric layers having different band gap energies. The variation of peak temperature Tm, corresponding to dielectric loss maximum, with frequency and fitting to Arrhenius law gives activation energy of 1.24 eV which is very close to the activation energy of oxygen vacancies in BaTiO3. Hence, oxygen vacancies are the active defects which are contributing to the relaxation process in these films.
Out-of-Plane and In-Plane Crystalline Orientations of Oxide Heterostructures of LSMO/ZnO
Authors: Uehara Kenichi , Reddy Sanapa Lakshmi , Okada Akira , Yokura Miyoshi , Kobayashi Shintaro , Inaba Katsuhiko , Nakajima Tomohiko , Tsuchiya Tetsuo , Endo Kazuhiro , Endo Tamio
Published: October 2012

Hexagonal ZnO was grown on hexagonal (001) sapphire substrate, then cubic La(Sr)MnO3(LSMO) was grown on ZnO underlayer by ion beam sputtering at substrate temperatures of 550-750°C to obtain double-layer of LSMO/ZnO. Out-of-plane (001) oriented ZnO was grown with in-plane orientation of [10-10](0001)ZnO//[11-20](0001)sapphire. Mixed phase of LSMO with out-of-plane (001), (110) and (111) orientations was grown on (001) ZnO usually. However each single phase of LSMO could be grown by controlling deposition conditions. The LSMO grains have their in-plane orientations of [110](110)LSMO //[10-10](0001)ZnO and [110](111)LSMO//[11-20](0001)ZnO.
A Novel Approach For Nanocarbon Composite Preparation
Authors: Nasibulin Albert G. , Koltsova Tatyana , Nasibulina Larisa I. , Anoshkin Ilya V. , Semencha Alexandr , Tolochko Oleg V. , Kauppinen Esko I.
Published: October 2012

Carbon nanotubes (CNTs), nanofibers (CNFs) and graphene are promising components for the next generation high performance structural and multi-functional composite materials. One of the largest obstacles to create strong, electrically or thermally conductive CNT/CNF composites is the difficulty of getting a good dispersion of the carbon nanomaterials in a matrix. Typically, time-consuming steps of the carbon nanomaterial purification, ultrasound sonication and functionalization are required. We utilized a new approach to grow CNTs/CNFs directly on the surface of matrix, matrix precursor or filler particles. As the precursor matrix and fillers we utilized cement (clinker), copper powder, fly ash particles, soil and sand. Carbon nanomaterials were successfully grown on these materials without additional catalyst. Investigations of the physical properties of the composite materials based on these carbon modified particles revealed enhancement in the mechanical and electrical properties.
Spontaneous atomic ordering and magnetism in epitaxially stabilized double-perovskites
Authors: Ohtomo Akira , Chakraverty Suvankar , Mashiko Hisanori , Oshima Takayoshi , Kawasaki Masashi
Published: October 2012

We report on the atomic ordering of B-site transition-metals and magnetic properties in double-perovskite oxides, La2CrFeO6 (LCFO) and La2VMnO6 (LVMO), which have never been reported to exist in ordered forms. These double-perovskite oxides are particularly interesting because of possible ferromagnetism (expected from the Kanamori-Goodenough rule for LCFO) and half-metallic antiferromagnetism (predicted for LVMO). Using pulsed-laser deposition technique with single solid-solution targets, we have prepared epitaxial films in ordered forms. Despite similar ionic characters of constituent transition-metals in each compound, the maximum B-site order attained was surprisingly high, ∼90% for LCFO and ∼80% for LVMO, suggesting a significant role of epitaxial stabilization in the spontaneous ordering process. Magnetization and valence state characterizations revealed that the magnetic ground state of both compounds was coincidently ferrimagnetic with saturation magnetization of ∼2μBper formula unit, unlike those predicted theoretically. In addition, they were found to be insulating with optical band-gaps of 1.6 eV and 0.9 eV for LCFO and LVMO, respectively. Our results present a wide opportunity to explore novel magnetic properties of binary transition-metal perovskites upon epitaxial stabilization of the ordered phase.
Nanophosphor-Embedded Oxide Glass-Matrix Nanocomposite for X-ray Imaging
Authors: Savage Nicholas , Wagner Brent , Zhang Yuelan , Lynch Brendan , Menkara Hisham , Summers Christopher , Kang Zhitao
Published: October 2012

Tb doped gadolinium fluoride nanophosphors embedded in an aluminosilicate glass matrix is reported for X-ray imaging applications. The nanocomposite scintillators were prepared by a melt-quench method followed by annealing. The GdF3:Tb nanophosphors precipitated within the oxide glass matrix during the processing and their luminescence and scintillation properties were investigated.
Extending the service life of Swiss bridges of cultural value
Authors: Brühwiler Eugen
Published: October 2012

Bridges of high cultural value and aesthetic quality deserve respectful treatment and construction interventions must balance these assets with the severe requirements of utilisation. This is particularly relevant to structural engineers and bridge owners involved in rehabilitation or modification interventions. This paper presents, by means of eight bridges in Switzerland, examples of how interventions can be performed with adequate respect to cultural value. It is argued that the preservation of cultural value may go hand in hand with socio-economic, environmental and technical requirements following the principles of sustainable development. These requirements are met through the application of advanced structural engineering methods specific to existing structures. Extending service life not only adds value to bridges – it also leads to an appreciation of the art of structural engineering and the identity of the engineers themselves.
Synthesizing larval competence dynamics and reef‐scale retention reveals a high potential for self‐recruitment in corals
Authors: Figueiredo Joana , Baird Andrew H. , Connolly Sean R.
Published: October 2012

Many organisms have a complex life‐cycle in which dispersal occurs at the propagule stage. For marine environments, there is growing evidence that high levels of recruitment back to the natal population (self‐recruitment) are common in many marine organisms. For fish, swimming behavior is frequently invoked as a key mechanism allowing high self‐recruitment. For organisms with weak‐swimming larvae, such as many marine invertebrates, the mechanisms behind self‐recruitment are less clear. Here, we assessed whether the combination of passive retention of larvae due to re‐circulation processes near reefs, and the dynamics of settlement competence, can produce the high levels of self‐recruitment previously estimated by population genetic studies for reef‐building corals. Additionally, we investigated whether time to motility, which is more readily measurable than competence parameters, can explain the between‐species variation in self‐recruitment. We measured the larval competence dynamics of broadcast‐spawning and brooding corals and incorporated these in a model of larval retention around reefs to estimate the potential for self‐recruitment and assess its variation among species and reefs. Our results suggest that the larvae of many corals, even those with an obligate planktonic phase, develop with sufficient rapidity to allow high levels of self‐recruitment, particularly for reefs with long water retention times. Time to motility explained 77–86% of the between‐species variation in potential self‐recruitment in scenarios with a realistic range of retention times. Among broadcast spawners, time to motility was strongly and positively correlated with egg size, i.e., broadcast spawner species with small eggs developed more rapidly and exhibited greater potential for self‐recruitment. These findings suggest that, along with water retention estimates, easy‐to‐measure species traits, such as egg size and time to motility, may be good predictors of potential self‐recruitment, and therefore may be used to characterize the spectrum of self‐recruitment in corals.
Tuberculous Coxitis: Diagnostic Problems and Varieties of Treatment: A Case Report§
Authors: Klein H , Seeger JB , Schleicher I
Published: October 2012

Although the prevalence of tuberculosis reduces, it still belongs to the most important infectious diseases worldwide even in industrial countries.

We report an unusual case of tuberculous coxitis in a 28-year-old healthy native female with recurrent hip pain. While X-ray and microbiological examination of the aspirate showed no abnormality, only extended diagnostic measurements and detailed history led to the diagnosis of TBC. Although the patient did not show any pulmonary symptoms open tuberculosis was confirmed. After a course of antibiotic treatment she underwent reconstructive surgery which consecutively improved range of motion. This case report emphasizes that tuberculosis should still be considered as a significant disease even in healthy patients with uncertain complaints in joints without significant initial radiographic abnormalities. We recommend the described diagnostic procedures as well as an antibiotic and surgical treatment.
Analysis of the heat affected zone in CO2 laser cutting of stainless steel
Authors: Madic Milos , Radovanovic Miroslav
Published: October 2012

This paper presents an investigation into the effect of the laser cutting
parameters on the heat affected zone in CO2 laser cutting of AISI 304
stainless steel. The mathematical model for the heat affected zone was
expressed as a function of the laser cutting parameters such as the laser
power, cutting speed, assist gas pressure and focus position using the
artificial neural network. To obtain experimental database for the
artificial neural network training, laser cutting experiment was planned as
per Taguchi?s L27 orthogonal array with three levels for each of the cutting
parameter. Using the 27 experimental data sets, the artificial neural
network was trained with gradient descent with momentum algorithm and the
average absolute percentage error was 2.33%. The testing accuracy was then
verified with 6 extra experimental data sets and the average predicting
error was 6.46%. Statistically assessed as adequate, the artificial neural
network model was then used to investigate the effect of the laser cutting
parameters on the heat affected zone. To analyze the main and interaction
effect of the laser cutting parameters on the heat affected zone, 2-D and
3-D plots were generated. The analysis revealed that the cutting speed had
maximum influence on the heat affected zone followed by the laser power,
focus position and assist gas pressure. Finally, using the Monte Carlo
method the optimal laser cutting parameter values that minimize the heat
affected zone were identified.
Experimental studies of parameters affecting the heat generation in friction stir welding process
Authors: Mijajlovic Miroslav , Pavlovic Nenad , Jovanovic Slobodan , Jovanovic Dragan , Milcic Miodrag
Published: October 2012

Heat generation is a complex process of transformation of a specific type of
energy into heat. During friction stir welding, one part of mechanical energy
delivered to the welding tool is consumed in the welding process, another is
used for deformational processes etc., and the rest of the energy is
transformed into heat. The analytical procedure for the estimation of heat
generated during friction stir welding is very complex because it includes a
significant number of variables and parameters, and many of them cannot be
fully mathematically explained. Because of that, the analytical model for the
estimation of heat generated during friction stir welding defines variables
and parameters that dominantly affect heat generation. These parameters are
numerous and some of them, e. g. loads, friction coefficient, torque,
temperature, are estimated experimentally. Due to the complex geometry of the
friction stir welding process and requirements of the measuring equipment,
adequate measuring configurations and specific constructional solutions that
provide adequate measuring positions are necessary. This paper gives an
overview of the process of heat generation during friction stir welding, the
most influencing parameters on heat generation, constructional solutions for
the measuring equipment needed for these experimental researches and examples
of measured values.
MHD effects on unstedy dynamic, thermal and diffusion boundary layer flow over a horizontal circular cylinder
Authors: Boricic Aleksandar , Jovanovic Milos , Boricic Branko
Published: October 2012

This paper is devoted to the analysis of unsteady two-dimensional dynamic,
thermal and diffusion magnetohydrodynamic laminar boundary layer flow over a
horizontal circular cylinder of incompressible and electrical conductivity
fluid, in a porous medium, in the presence of a heat source or sink, and
chemical reactions. The present magnetic field is homogenous and
perpendicular to the body surface. It is assumed that the induction of the
outer magnetic field is the function of the longitudinal coordinate and time.
Fluid electrical conductivity is constant. The outer electric field is
neglected and the magnetic Reynolds number is significantly lower than one i.
e. the considered the problem is in induction-less approximation. Free stream
velocity, temperature and concentration on the body are arbitrary
differentiable functions. The developed governing boundary layer equations
and associated boundary conditions are converted into a nondimensional form
using a suitable similarity transformation and similarity parameters. The
system of dimensionless equations is solved using the finite difference
method and iteration method. Numerical results are obtained and presented for
incompressible fluid for different numbers, such as Sc, Pr, Ec and magnetic
number, and the parameter of the porous medium, temperature parameters,
thermal parameter, diffusion parameters and chemical reaction parameter. The
solutions for the flow, temperature and diffusion transfer and other integral
characteristics, boundary layer, are evaluated numerically for different
values of the magnetic field. Transient effects of velocity, temperature and
diffusion are analyzed. A part of obtained results is given in the form of
figures and corresponding conclusions.
A new approach in CHP steam turbines thermodynamic cycles computations
Authors: Grkovic Vojin , Zivkovic Dragoljub , Gutesa Milana
Published: October 2012

This paper presents a new approach in mathematical modeling of thermodynamic
cycles and electric power of utility district-heating and cogeneration steam
turbines. The approach is based on the application of the dimensionless mass
flows, which describe the thermodynamic cycle of a combined heat and power
steam turbine. The mass flows are calculated relative to the mass flow to low
pressure turbine. The procedure introduces the extraction mass flow load
parameter ?h which clearly indicates the energy transformation process, as
well as the cogeneration turbine design features, but also its fitness for
the electrical energy system requirements. The presented approach allows fast
computations, as well as direct calculation of the selected energy efficiency
indicators. The approach is exemplified with the calculation results of the
district heat power to electric power ratio, as well as the cycle efficiency,
versus ?h. The influence of ?h on the conformity of a combined heat and power
turbine to the grid requirements is also analyzed and discussed.
Leakage quantification of compressed air on pipes using thermovision
Authors: Dudic Slobodan , Ignjatovic Ivana , Seslija Dragan , Blagojevic Vladislav , Stojiljkovic Miodrag
Published: October 2012

Nondestructive testing methods are increasingly in use. With these methods it
is possible to obtain the desired information about the system, without
altering or damaging it in any way. This paper examines the possibilities of
applying these methods in the quantification of losses incurred by leaking of
compressed air from the system in the terms of increasing energy efficiency
of the system. The emphasis is on the application of ultrasound detector and
IR (infrared) thermographic camera. The potentials and limitations of these
technologies are analyzed for leakage quantification on a steel pipe in
compressed air systems, as well as the reliability and accuracy of the
results thus obtained.
Numerical simulation of wall temperature on gas pipeline due to radiation of natural gas during combustion
Authors: Ilic Marko , Stefanovic Velimir , Ilic Gradimir , Pavlovic Sasa , Kustrimovic Dragan
Published: October 2012

This paper presents one of the possible hazardous situations during
transportation of gas through the international pipeline. It describes the
case when at high-pressure gas pipeline, due to mechanical or chemical
effect, cracks and a gas leakage appears and the gas is somehow triggered to
burn. As a consequence of heat impingement on the pipe surface, change of
material properties (decreasing of strength) at high temperatures will occur.
In order to avoid greater rapture a reasonable pressure relief rate needs to
be applied. Standards in this particular domain of depressurizing procedure
are not so exact (DIN EN ISO 23251; API 521). This paper was a part of the
project to make initial contribution in defining the appropriate procedure of
gas operator behaving during the rare gas leakage and burning situations on
pipeline network. The main part of the work consists of two calculations. The
first is the numerical simulation of heat radiation of combustible gas, which
affects the pipeline, done in the FLUENT software. The second is the
implementation of obtained results as a boundary condition in an additional
calculation of time resolved wall temperature of the pipe under consideration
this temperature depending on the incident flux as well as a number of other
heat flow rates, using the Matlab. Simulations were done with the help of the
?E.ON Ruhrgas AG? in Essen.
Low-pressure reversible axial fan designed with different specific work of elementary stages
Authors: Bogdanovic Bozidar , Spasic Zivan , Bogdanovic-Jovanovic Jasmina
Published: October 2012

Low-pressure axial fan impellers designed according to the principle of equal
specific work of all elementary stages have blades whose profile near the fan
hub is under a significantly larger inclination angle than at the impeller
periphery. In order to minimize the spatial curvature of the fan blades and
the fan hub length, impeller blades of low-pressure axial fans can be
designed with different specific work of elementary stages, so that the
specific work of elementary stages is smaller at the hub than at the
periphery. This paper presents the operating characteristics of a
low-pressure reversible axial fan with straight blade profiles, designed with
different specific work of elementary stages. The fan was tested on a
standard test rig, with air intake loading on the suction side of the fan.
The Poincaré-Bendixson Theorem: from Poincaré to the XXIst century
Authors: Ciesielski Krzysztof
Published: October 2012

The Poincaré-Bendixson Theorem and the development of the theory are presented — from the papers of Poincaré and Bendixson to modern results.
Filippov Lemma for certain second order differential inclusions
Authors: Bartuzel Grzegorz , Fryszkowski Andrzej
Published: October 2012

In the paper we give an analogue of the Filippov Lemma for the second order differential inclusions with the initial conditions y(0) = 0, y′(0) = 0, where the matrix A ∈ ℝd×d
and multifunction is Lipschitz continuous in y with a t-independent constant l. The main result is the following: Assume that F is measurable in t and integrably bounded. Let y
0 ∈ W
2,1 be an arbitrary function fulfilling the above initial conditions and such that where p
0 ∈ L
1[0, 1]. Then there exists a solution y ∈ W
2,1 to the above differential inclusions such that a.e. in [0, 1], .
Global bifurcation of homoclinic trajectories of discrete dynamical systems
Authors: Pejsachowicz Jacobo , Skiba Robert
Published: October 2012

We prove the existence of an unbounded connected branch of nontrivial homoclinic trajectories of a family of discrete nonautonomous asymptotically hyperbolic systems parametrized by a circle under assumptions involving topological properties of the asymptotic stable bundles.
Minimization of the number of periodic points for smooth self-maps of simply-connected manifolds with periodic sequence of Lefschetz numbers
Authors: Graff Grzegorz , Kaczkowska Agnieszka
Published: October 2012

Let f be a smooth self-map of m-dimensional, m ≥ 4, smooth closed connected and simply-connected manifold, r a fixed natural number. For the class of maps with periodic sequence of Lefschetz numbers of iterations the authors introduced in [Graff G., Kaczkowska A., Reducing the number of periodic points in smooth homotopy class of self-maps of simply-connected manifolds with periodic sequence of Lefschetz numbers, Ann. Polon. Math. (in press)] the topological invariant J[f] which is equal to the minimal number of periodic points with the periods less or equal to r in the smooth homotopy class of f.

In this paper the invariant J[f] is computed for self-maps of 4-manifold M with dimH
2(M; ℚ) ≤ 4 and estimated for other types of manifolds. We also use J[f] to compare minimization of the number of periodic points in smooth and in continuous categories.
Equivariant Morse equation
Authors: Styborski Marcin
Published: October 2012

The paper is concerned with the Morse equation for flows in a representation of a compact Lie group. As a consequence of this equation we give a relationship between the equivariant Conley index of an isolated invariant set of the flow given by .x = −∇f(x) and the gradient equivariant degree of ∇f. Some multiplicity results are also presented.
Seiberg-Witten invariants, the topological degree and wall crossing formula
Authors: Starostka Maciej
Published: October 2012

Following S. Bauer and M. Furuta we investigate finite dimensional approximations of a monopole map in the case b
1 = 0. We define a certain topological degree which is exactly equal to the Seiberg-Witten invariant. Using homotopy invariance of the topological degree a simple proof of the wall crossing formula is derived.
Elliptic problems in generalized Orlicz-Musielak spaces
Authors: Gwiazda Piotr , Minakowski Piotr , Wróblewska-Kamińska Aneta
Published: October 2012

We consider a strongly nonlinear monotone elliptic problem in generalized Orlicz-Musielak spaces. We assume neither a Δ2 nor ∇2-condition for an inhomogeneous and anisotropic N-function but assume it to be log-Hölder continuous with respect to x. We show the existence of weak solutions to the zero Dirichlet boundary value problem. Within the proof the L
∞-truncation method is coupled with a special version of the Minty-Browder trick for non-reflexive and non-separable Banach spaces.
Two Patterns of Changes in Nasal Nitric Oxide after Lysine Aspirin Nasal Challenge in Patients with Aspirin-exacerbated Respiratory Disease
Authors: Tworek Damian , Kuprys-Lipinska Izabela , Pietruszewska Wioletta , Kuna Piotr
Published: October 2012

Background

Nasal nitric oxide (nNO) levels after nasal lysine acetylsalicylic acid (lys-ASA) challenge have not been determined. This study was designed to determine a pattern of changes after lys-ASA challenge in aspirin-exacerbated respiratory disease (AERD) patients and to evaluate the usefulness of nNO measurements in the assessment of lys-ASA nasal challenge outcome.

Methods

Eighteen patients with aspirin hypersensitivity, nasal polyps, and asthma were included. Aspirin-tolerant control groups consisted of 10 healthy volunteers without asthma and nasal polyps and 10 patients with nasal polyps without asthma. All subjects underwent nasal challenge with lys-ASA. nNO was measured before and 1, 2, 4, and 24 hours after control solution and lys-ASA administration.

Results

A significant fall in nNO levels was noted in AERD patients with a positive result to challenges at time points 1 hour (p = 0.0033), 2 hours (p = 0.0033), and 3 hours (p = 0.026) after lys-ASA. A trend toward higher nNO concentrations was observed after lys-ASA challenge at the 2-hour (p = 0.018) and 4-hour (p = 0.018) time points compared with baseline in subjects with AERD and a clinically negative re to the challenge. No significant changes in nNO levels after the challenge were observed in control groups. The combined increase and decrease in nNO levels gave the sensitivity as 0.94 and specificity 1.00 at best.

Conclusion

nNO levels decrease after lys-ASA nasal challenge in subjects with AERD and a clinically positive result of the challenge. An unexpected trend toward an increase in nNO levels is observed in subjects with AERD and a clinically negative result of the challenge.
Performance Evaluation of a Lithium-Chloride Absorption Refrigeration and an Assessment of Its Suitability for Biomass Waste Heat
Authors: Oberweis Sacha , Al-Shemmeri Tariq
Published: October 2012

This paper presents a computer model that will evaluate the performance of a thermo-chemical accumulator. The model is based on operational data such as temperatures and flow rates. The ultimate goal for this model is to estimate the coefficient of performance (COP) of this unit when run on hot water from biomass combustion as the heat source. The outputs of the model are verified by comparing the simulation of the actual machine with published experimental data. The computed results for cooling COP are within 10% of the measured data. The simulations are all run for heat load temperatures varying between 80 °C and 110 °C. As expected, simulation results showed an increase in COP with increased heat source temperatures. The results demonstrate that the potential of combined solar and biomass combustion as a heat source for absorption cooling/heating in climates with low solar radiation can be coupled with biomass waste.
A Polarized Atmospheric Radiative Transfer Model for Calculations of Spectra of the Stokes Parameters of Shortwave Radiation Based on the Line-by-Line and Monte Carlo Methods
Authors: Fomin Boris , Falaleeva Victoria
Published: October 2012

This paper presents a new version of radiative transfer model called the Fast Line-by-Line Model (FLBLM), which is based on the Line-by-Line (LbL) and Monte Carlo (MC) methods and rigorously treats particulate and molecular scattering alongside absorption. The advantage of this model consists in the use of the line-by-line model that allows for the computing of high-resolution spectra quite quickly. We have developed the model by taking into account the polarization state of light and carried out some validations by comparison against benchmark results. FLBLM calculates the Stokes parameters spectra of shortwave radiation in vertically inhomogeneous atmospheres. This update makes the model applicable for the assessment of cloud and aerosol influence on radiances as measured by the SW high-resolution polarization spectrometers. In sample results we demonstrate that the high-resolution spectra of the Stokes parameters contain more detailed information about clouds and aerosols than the medium- and low-resolution spectra wherein lines are not resolved. The presented model is rapid enough for many practical applications (e.g., validations) and might be useful especially for the remote sensing. FLBLM is suitable for development of the reliable technique for retrieval of optical and microphysical properties of clouds and aerosols from high-resolution satellites data.
Fruits and Vegetables Consumption and Associated Factors among In-School Adolescents in Five Southeast Asian Countries
Authors: Peltzer Karl , Pengpid Supa
Published: October 2012

The aim of the study was to assess the prevalence of fruits and vegetable consumption and associated factors among Southeast Asian in-school adolescents. Data were collected by self-report questionnaire from nationally representative samples (total 16,084) of school children aged 13 to 15 years in five Southeast Asian countries. Overall, 76.3% of the 13 to 15 year-olds had inadequate fruits and vegetables consumptions (less than five servings per day); 28% reported consuming fruits less than once per day and 13.8% indicated consuming vegetables less than once per day. In multivariable analysis, lack of protective factors and being physically inactive were associated with inadequate fruits and vegetable consumption, and sedentary behaviour and being overweight was protective of inadequate fruits and vegetable consumption. The results stress the need for intervention programmes aimed at increased consumption of fruits and vegetables, targeting proximal factors such as the family environment and distal factors by aiming at integrating other risk factors such as physical activity into health promotion among adolescents.
A Molecular Dynamics (MD) and Quantum Mechanics/Molecular Mechanics (QM/MM) Study on Ornithine Cyclodeaminase (OCD): A Tale of Two Iminiums
Authors: Ion Bogdan F. , Bushnell Eric A. C. , Luna Phil De , Gauld James W.
Published: October 2012

Ornithine cyclodeaminase (OCD) is an NAD+-dependent deaminase that is found in bacterial species such as Pseudomonas putida. Importantly, it catalyzes the direct conversion of the amino acid L-ornithine to L-proline. Using molecular dynamics (MD) and a hybrid quantum mechanics/molecular mechanics (QM/MM) method in the ONIOM formalism, the catalytic mechanism of OCD has been examined. The rate limiting step is calculated to be the initial step in the overall mechanism: hydride transfer from the L-ornithine’s Cα–H group to the NAD+ cofactor with concomitant formation of a Cα=NH2+ Schiff base with a barrier of 90.6 kJ mol−1. Importantly, no water is observed within the active site during the MD simulations suitably positioned to hydrolyze the Cα=NH2+ intermediate to form the corresponding carbonyl. Instead, the reaction proceeds via a non-hydrolytic mechanism involving direct nucleophilic attack of the δ-amine at the Cα-position. This is then followed by cleavage and loss of the α-NH2 group to give the Δ1-pyrroline-2-carboxylate that is subsequently reduced to L-proline.
Formulation Optimization of a Palm-Based Nanoemulsion System Containing Levodopa
Authors: Zainol Syafinaz , Basri Mahiran , Basri Hamidon Bin , Shamsuddin Ahmad Fuad , Abdul-Gani Siti Salwa , Karjiban Roghayeh Abedi , Abdul-Malek Emilia
Published: October 2012

Response surface methodology (RSM) was utilized to investigate the influence of the main emulsion composition; mixture of palm and medium-chain triglyceride (MCT) oil (6%–12% w/w), lecithin (1%–3% w/w), and Cremophor EL (0.5%–1.5% w/w) as well as the preparation method; addition rate (2–20 mL/min), on the physicochemical properties of palm-based nanoemulsions. The response variables were the three main emulsion properties; particle size, zeta potential and polydispersity index. Optimization of the four independent variables was carried out to obtain an optimum level palm-based nanoemulsion with desirable characteristics. The response surface analysis showed that the variation in the three responses could be depicted as a quadratic function of the main composition of the emulsion and the preparation method. The experimental data could be fitted sufficiently well into a second-order polynomial model. The optimized formulation was stable for six months at 4 °C.
Overcoming the Slow Recovery of MOX Gas Sensors through a System Modeling Approach
Authors: Monroy Javier G. , González-Jiménez Javier , Blanco Jose Luis
Published: October 2012

Metal Oxide Semiconductor (MOX) gas transducers are one of the preferable technologies to build electronic noses because of their high sensitivity and low price. In this paper we present an approach to overcome to a certain extent one of their major disadvantages: their slow recovery time (tens of seconds), which limits their suitability to applications where the sensor is exposed to rapid changes of the gas concentration. Our proposal consists of exploiting a double first-order model of the MOX-based sensor from which a steady-state output is anticipated in real time given measurements of the transient state signal. This approach assumes that the nature of the volatile is known and requires a precalibration of the system time constants for each substance, an issue that is also described in the paper. The applicability of the proposed approach is validated with several experiments in real, uncontrolled scenarios with a mobile robot bearing an e-nose.
HIV–1 Dynamics: A Reappraisal of Host and Viral Factors, as well as Methodological Issues
Authors: Prentice Heather A. , Tang Jianming
Published: October 2012

The dynamics of HIV–1 viremia is a complex and evolving landscape with clinical and epidemiological (public health) implications. Most studies have relied on the use of set–point viral load (VL) as a readily available proxy of viral dynamics to assess host and viral correlates. This review highlights recent findings from population–based studies of set–point VL, focusing primarily on robust data related to host genetics. A comprehensive understanding of viral dynamics will clearly need to consider both host and viral characteristics, with close attention to (i) the timing of VL measurements, (ii) the biology of viral evolution, (iii) compartments of active viral replication, (iv) the transmission source partner as the immediate past microenvironment, and (v) proper application of statistical models.
Paper modified with ZnO nanorods – antimicrobial studies
Authors: Jaisai Mayuree , Baruah Sunandan , Dutta Joydeep
Published: October 2012

Paper with antimicrobial properties was developed through in situ growth of ZnO nanorods. The targeted application for this type of paper is in health centers as wallpaper, writing paper, facemasks, tissue paper, etc. The paper was tested on three model microbes, Gram-positive bacteria Staphylococcus aureus, Gram-negative bacteria Escherichia coli and common airborne fungus Aspergillus niger. No viable bacterial colonies or fungal spores could be detected in the areas surrounding test samples of the antimicrobial paper. Gram-negative bacteria Escherichia coli were found to be inhibited in an area that is 239% and 163% the area of the paper sample under different room lighting conditions, i.e., halogen and fluorescent lamp illumination, respectively. For Gram-positive bacteria Staphylococcus aureus the zones of inhibition surrounding the paper samples are 102% and 70%, and for Aspergillus niger, 224% and 183% of the sample area, under similar lighting conditions.
Rates of Emergence of HIV Drug Resistance in Resource-Limited Settings: A Systematic Review
Authors: Stadeli Kathryn M , Richman Douglas D
Published: October 2012

Background

The increasing availability of antiretroviral therapy (ART) has improved survival and quality of life for many infected with HIV, but can also engender drug resistance. This review summarizes the available information on drug resistance in adults in resource-limited settings.

Methods

The online databases PubMed and Google Scholar, pertinent conference abstracts and references from relevant articles were searched for publications available before November 2011. Data collected after ART rollout were reviewed.

Results

A total of 7 studies fulfilled the criteria for the analysis of acquired drug resistance and 22 fulfilled the criteria for the analysis of transmitted drug resistance (TDR). Acquired resistance was detected in 7.2% of patients on ART for 6–11 months, 11.1% at 12–23 months, 15.0% at 24-35 months, and 20.7% at ≥36 months. Multi-class drug resistance increased steadily with time on ART. The overall rate of TDR in all resource-limited countries studied was 6.6% (469/7,063). Patients in countries in which ART had been available for ≥5 years were 1.7x more likely to have TDR than those living in a country where ART had been available for <5 years ( P<0.001). The reported prevalence of TDR was 5.7% (233/4,069) in Africa, 7.6% (160/2,094) in Asia and 8.4% (76/900) in Brazil.

Conclusions

The emergence of drug resistance following access to ART in resource-limited settings resembles what was seen in resource-rich countries and highlights the need for virological monitoring for drug failure, drug resistance testing and alternative drug regimens that have proven beneficial in these resource-rich settings.
Dépression prénatale et stratégies de « coping »
Authors: de Noose Lisa
Published: October 2012

Résumé La présente étude est issue de la récente thèse doctorale soutenue par l’auteur et portant sur les facteurs de vulnérabilité et de protection de la dépression maternelle prénatale dans ses dimensions démographiques, psychosociales et intrapsychiques. Les résultats présentés dans le cadre de cet article portent sur les mécanismes de coping privilégiés d’une part par les femmes dépressives lors de leur grossesse, et d’autre part, par celles ne présentant pas de symptomatologie dépressive durant cette période. Les analyses statistiques portant sur un échantillon total de 190 sujets, la mise en évidence de liens de corrélation significatifs permettent de dégager la présence de stratégies de coping pouvant être considérées comme facteur de protection versus de vulnérabilisation pour la présence d’une dépression maternelle prénatale.
Effets du stress prénatal sur le développement cognitif et psychoaffectif de l'enfant : une revue de la question
Authors: Gallois Thomas , Wendland Jaqueline
Published: October 2012

Résumé Les études explorant les effets du stress prénatal sur l’enfant à naître se développent depuis une quarantaine d’années. D’abord centrées sur la période périnatale, les recherches explorent désormais les effets à plus long terme sur le développement de l’enfant au niveau cognitif et psychoaffectif. Sur le plan cognitif, les résultats montrent des effets du stress prénatal sur les capacités intellectuelles, langagières et attentionnelles de l’enfant. Sur le plan psychoaffectif, l’impact du stress prénatal sur le tempérament de l’enfant ainsi que sur le risque psychopathologique a été mis en évidence. Il ressort que le moment de survenue du stress a une incidence notable sur les effets qu’il produira sur l’enfant à venir, effets qui peuvent aussi varier en fonction du sexe du fœtus. Des hypothèses physiologiques et de programmation du développement fœtal peuvent en partie expliquer ces résultats. Toutefois, d’autres variables peuvent pondérer les effets du stress prénatal sur la femme et sur le développement de l’enfant, comme le soutien social ou le coping . Cet article propose une revue de la littérature à propos des effets du stress prénatal sur le développement cognitif et psychoaffectif de l’enfant. Nous abordons également les liens qui ont pu être établis entre le stress prénatal et le développement de certaines pathologies telles que l’autisme, la schizophrénie et la dépression.
Pronostic létal : les risques de l'annonce
Authors: Bernard-Lemonnier Sophie
Published: October 2012

Résumé Une décennie vient de s’écouler depuis la parution, en France, de la loi du 4 mars 2002, relative aux droits des malades et à la qualité du système de santé, posant l’information à donner aux malades comme un droit inaliénable. Cependant, malgré la prudente précaution, inscrite dans cette même loi, de respecter la volonté d’ignorance du malade, nous ne pouvons que constater que le corps médical a tendance à s’orienter vers une annonce systématique du caractère létal de la maladie qui les touche. L’objet de cet article est d’en relever les effets délétères et de réintroduire une réflexion éthique concernant l’annonce du pronostic létal, lorsque celle-ci tend à se systématiser, en dépit des malades eux-mêmes, notamment dans leur sollicitation en vue d’obtenir la rédaction de leurs directives anticipées.
L'envol des montgolfières ou l'accompagnement d'une ultime évolution...
Authors: Saillour Claire
Published: October 2012

Résumé La fin de vie comprend un certain déroulement, une temporalité qui permet l’accompagnement de celui qui part. Cet accompagnement peut être l’occasion pour lui comme à tout autre moment de sa vie, d’une ultime évolution. La vie le quitte, la mort le prend, c’est le temps de l’agonie (le combat). Les soignants s’accompagnent également mutuellement dans ce travail, et la tâche de mise en mots de leur vécu participe au tissage et au récit d’une histoire commune.