bluuebunny/crossref_metadata_2025 huggingface dataset:
Healing of Microsphere Cores in Sandwich Composites
Authors: Phillips David M. , Baur Jeffery W.
Published: April 2011

The primary purposes of a core in a sandwich composite are to keep the face sheets separated by a fixed distance and to transmit shear stresses. Syntactic foam cores consisting of hollow glass microspheres and resin can form strong, lightweight cores. By underfilling the interstitial space in a packed microsphere bed with a binder, a three-phase syntactic foam is created that has a percolated void network. In a sealed sandwich composite, a void network allows for the entire core of the sandwich composite to be evacuated and mechanically compressed by the exterior pressure. By combining this compression with a heating cycle, it is possible to repair core cracking and core/face sheet interface debonding when a reversible binder is used. Upon cooling, the healed sandwich restores its properties. We examine the relation between the mechanical properties of these sandwich composites and the healing methodologies.
Enhanced Electromechanical Responses of IPCNC Actuators
Authors: Liu Yang , Liu Sheng , Cebeci Hulya , de Villoria Roberto G. , Lin Jun-Hong , Wardle Brian L. , Zhang Q. M.
Published: April 2011

In this presentation, we will show several progresses in Ionic Polymer Conductor Network Composite Actuators (IPCNC) studies. First of all, we successfully fabricated ultra high volume fraction vertically aligned carbon nanotubes (VA-CNTs)/polymer composite electrodes which markedly improved the electromechanical performance of IPCNC actuators. The experimental results show that the continuous paths through inter-VA-CNT channels and low electrical conduction resistance due to the continuous CNTs lead to fast actuation speed (>10% strain/second). The experimental results also demonstrate that the VA-CNTs create anisotropic elastic property in the composite electrodes, which suppresses the vertical strain and markedly enhances the actuation strain (>8% strain under 4 volts). The data here show the promise of optimizing the electrode morphology in IPCNCs by the ultrahigh volume fraction VA-CNTs for ionic polymer actuators to achieve high performance.
Development of a 6-Channel Power Controller for Simultaneous Actuation and Resistance Measurement of SMA Wires
Authors: Hangekar Rohan , Furst Stephen , Seelecke Stefan
Published: April 2011

The use of ‘multifunctional’ Shape Memory Alloy wires as embedded actuators and sensors has been proposed for numerous novel applications. The SMA wires are actuated as a result of the Joule heating induced by passing electric current through it. The resistance of the SMA wire can simultaneously be measured during its actuation enabling it to be used as sensor data that relates to the strain and temperature of the wire. In order to control actuation stroke from the SMA wire, the Joule heating (electric power supplied to the SMA wire) of the wire needs to be controlled. Therefore, a 6-channel power controller device has been developed that simultaneously controls the power supplied to six different SMA wires and measures the resistance of these wires during excitation. This paper continues from the previously presented concept of a multi-channel power controller implementation. The focus of this paper is to discuss the operation, calibration methods and optimization techniques to improve the performance and robustness of the device and to eliminate the issues in multi-channel implementation. Further, this device is implemented in a test setup to study the position control of SMA wire using resistance feedback. Results of these tests can be utilized in practical applications involving SMA wires as embedded actuators and sensors, such as Smart Inhaler system being developed at North Carolina State University.
Tensile Properties of Insect Tracheal Tubes
Authors: Webster Matthew R. , De Vita Raffaella , Twigg Jeffrey N. , Socha John J.
Published: April 2011

Insects are able to efficiently transport oxygen to all the cells in their body by means of a complex network of tracheal tubes. In this study, the mechanical properties of such tracheal tubes excised from American (Periplaneta Americana) cockroaches were investigated. Toward this end, a micron-scale tensile testing machine was designed and used in order to apply radial loads to ring-shaped specimens obtained from tracheal tubes. The machine was equipped with a video camera system for accurate strain measurements. The results indicated that the elastic modulus of these tracheal tubes was on the order of 273 MPA and the ultimate stress and strain of this material in the radial direction was 9.8 MPa and 11% respectively.
Correlating Shear Slip and Contact Pressure for Health Monitoring of Bolted Joints in Aerospace Structures
Authors: Jalalpour Mohammad , Reda Taha Mahmoud , Austin Eric
Published: April 2011

Bolted joints are critical components in aerospace structures. Checking the integrity of these connections, although time consuming, is a necessary step before launching aerospace vehicles and satellites. Recent advances in structural health monitoring (SHM) suggest the possible use of SHM technologies to assess the integrity of these joints. Moreover, there exists a need for continuous monitoring of aerospace structures after launching. This continuous monitoring requires relating damage features that can be extracted using sensing techniques (e.g. ultrasonic methods) to physical quantities representing the structural integrity of bolted joints typically related to contact pressure. This paper describes an experimental effort to correlate shear slip measurements of a bolted connection to contact pressure. The contact pressure map (spatial distribution of contact pressure) is calibrated to the torque applied to the bolted connection. Loading and unloading experiments on the joint allowed separating elastic and shear slip displacements. Shear slip is then correlated to contact pressure maps. Further efforts are underway to connect these measures to SHM metrics.
Shear Morphing Skins: Simulation and Testing of Optimized Design
Authors: Asheghian Laila , Reich Greg , Enke Andrew , Kudva Jay
Published: April 2011

NextGen’s work on the DARPA sponsored Next Generation Morphing Aircraft Structures (N-MAS) program [1]–[6] designed and successfully tested novel morphing wing designs that were enabled by “shear-morphing” skins capable of withstanding up to 400 psf air-loads while simultaneously undergoing shear strains in excess of 100%. These ad-hoc skin designs consisted of high-strain silicone facesheets supported by an intricate aluminum under-structure made of thin, closely-spaced aluminum ribbons glued to the facesheets and bounded by pin-jointed frames. While these performed well in wind tunnel and flight tests, two areas for improvement were identified: (1) reduction in manufacturing complexity, and (2) reduction in actuation force requirements. In this research program, through use of high-fidelity modeling (ANSYS) and in-house testing, a new design was obtained that met both of the desired objectives using novel materials and single-piece support structure fabrication. The optimization modeling code was designed to be adaptable to a range of design inputs, and as such can be used on future programs as well, at various scales from UAV to MAV. The thorough understanding of the design space gained from non-linear FEM modeling guided design, manufacturing and testing in the later portion of the research. Using the optimized design from analysis, as well as variations in facesheet prestrain, the ANSYS code was validated through manufacture and testing of panels. This report details the results of testing and compares them to both predictions of the ANSYS code and N-MAS baseline designs values through various test setups. Results presented include shear morphing forces/energy, out-of-plane displacement under air loading, and 3D photometric analysis of shearing panels for identification of stresses/strains and wrinkling initialization in the skin. Testing provided substantiation of the ANSYS code, matching the general predicted trends despite wide variability in material properties.
Smart Needling System for Fully Conformal Radiation Dose Delivery in Treating Prostate Cancer
Authors: Podder Tarun K. , Hutapea Parsaoran , Darvish Kurosh , Dicker Adam , Yu Yan
Published: April 2011

The objective of the project is to design a new distributed actuation system along the needle’s body (active/smart needling), exploiting the steering advantage of the bevel-tip geometry (bevel angle), developing a flexible needle body having sensors at the needle tip and along the body for real-time tracking/detection of the needle using a feedback closed-loop control for real-time steering of the needle toward the target. We present two types of needle design and actuation techniques: Longitudinal Body Segment (LoBS) design, and Lateral Body Segment (LaBS) design. For LoBS design, the needle is separated into multiple segments along its length to improve maneuverability of the needle tip. This device incorporates four Nitinol wires per segment about its tubular substructure. The ends of each wire are secured to steel anchors, which are attached to non-conducting collets. The displacement and the speed of actuation is a function of the power supplied to each Nitinol wire. The amount of power is controlled using Pulse Width Modulation. Bending in arbitrary directions can be accomplished by adjusting the electrical duty cycles of the Nitinol wires. For LaBS design, the needle body is made of Nitinol having lateral segments (two or multiple of paired segments along the needle length). Each segment is an actuator made of Nitinol, which will be capable of manipulating the needle tip according to the sensory feedback information. The distal end of the actuator segments of the needle body are hinged at different points when the needle needs to be curved down the needle body segment can be actuated so that force which will produce moment about the opposite point. Therefore, by manipulating the force the amount of needle curvature can be controlled. By rotating the needle at desired angle, any needle trajectory can be achieved for reaching the target while avoiding obstacles (or critical organ) and conforming organ geometry.
Nanostructure and magnetic properties of c-axis oriented L10-FePt nanoparticles and nanocrystalline films on polycrystalline TiN underlayers
Authors: Tsuji Yoshiko , Noda Suguru , Nakamura Shinichi
Published: April 2011

We performed a systematic study of the nanostructure and magnetic properties of FePt on templates of either (200)-oriented polycrystalline TiN underlayers with in-plane grain sizes from 5.8 to 10 nm (poly-TiN) or highly (200)-textured TiN underlayers epitaxially grown on single-crystalline MgO (100) substrates (epi-TiN). For small nominal FePt thicknesses (0.7–8.0 nm), FePt forms particulate films with the magnetic easy axis perpendicular to the film plane on every template TiN underlayer. In addition, the coercivity of nominally 1.4-nm-thick FePt at 300 K in the out-of-plane direction increases from 5.3 kOe for 5.8-nm-sized poly-TiN to 12.9 kOe for 10-nm-sized poly-TiN and reaches 16.3 kOe for epi-TiN, which shows that the coercivity strongly depends on the degree of the c-axis orientation. For larger FePt nominal thicknesses (16–64 nm), FePt particles percolate and form continuous films, and the direction of the easy magnetic easy axis becomes random. The coercivity of nominally 64-nm-thick FePt at 300 K in the out-of-plane direction is still as large as 8.8 kOe for 10-nm-sized poly-TiN, but it drastically decreases to 0.5 kOe for epi-TiN. The absence of in-plane texture in the FePt layer on the poly-TiN suppresses the decrease in coercivity, which prevents domain-wall displacement.
Switched-On Physics: If you can dream it, you can do it
Authors: Graham Scotty
Published: April 2011

As classroom science teachers, we are all often reminded of the inevitable and sometimes not small challenges that face us in captivating and keeping the interest of our students. To give additional relevance and life to my teaching of physics, I decided to integrate global, hands-on projects into my approach. I decided from the onset that the projects had to be innovative, spectacular, and creative, and they must include input from students and colleagues from their inception. This chosen course of action resulted in the development of a dynamic three-year physics odyssey culminating with the Switched-On Physics Project. In this paper, I describe the program and encourage other teachers to consider engaging in projects that capture their interest and that of their students.
Observation of Orbital Currents in CuO
Authors: Scagnoli V. , Staub U. , Bodenthin Y. , de Souza R. A. , García-Fernández M. , Garganourakis M. , Boothroyd A. T. , Prabhakaran D. , Lovesey S. W.
Published: April 2011

Resonant x-ray scattering is used to detect microscopic loop currents within the plane of cupric oxide.
Minor Splicing, Disrupted
Authors: Pessa Heli K. J. , Frilander Mikko J.
Published: April 2011

The repertoire of spliceosomal components containing mutations associated with diseases is expanded to include a small nuclear RNA.
First Specific Drugs Raise Hopes for Hepatitis C
Authors: Enserink Martin
Published: April 2011

Regulatory agencies in both the United States and Europe are soon expected to green-light the first two antiviral drugs specifically developed to treat chronic hepatitis C, a treacherous infection that can cause cirrhosis of the liver and liver cancer, often decades after infection occurs.
Signature on Visitor's Form Fuels
Stanford
v.
Roche
Court Battle
Authors: Marshall Eliot
Published: April 2011

A visiting university scientist's signature on a visitor's agreement at a biotech company is at the center of a major patent fight before the U.S. Supreme Court.
Winds of Change Leave Bioscientists Scrambling
Authors: Normile Dennis
Published: April 2011

In a 5-year plan launched this month, Singapore will boost public spending on research by 20% compared with spending during the previous 5 years. This largesse comes with a price: The government is demanding more economic bang from its research bucks.
Can Biotech and Organic Farmers Get Along?
Authors: Stokstad Erik
Published: April 2011

The U.S. Department of Agriculture has been taking a closer look at the impact of biotech crops on organic farms. Research is providing tools to help them thrive side by side, but the politics are tricky.
Phylogenetic analysis of C, M, N, and U genomes and their relationships with Triticum and other related genomes as revealed by LMW-GS genes at Glu-3 loci
Authors: Wang Shunli , Li Xiaohui , Wang Ke , Wang Xiaozheng , Li Shanshan , Zhang Yanzhen , Guo Guangfang , Zeller Friedrich J. , Hsam Sai L. K. , Yan Yueming
Published: April 2011

Phylogenetic relationships between the C, U, N, and M genomes of Aegilops species and the genomes of common wheat and other related species were investigated by using three types of low-molecular-weight glutenin subunit (LMW-GS) genes at Glu-3 loci. A total of 20 LMW-GS genes from Aegilops and Triticum species were isolated, including 11 LMW-m type and 9 LMW-i type genes. Particularly, four LMW-m type and three LMW-i type subunits encoded by the genes on the C, N, and U genomes possessed an extra cysteine residue at conserved positions, which could provide useful information for understanding phylogenetic relationships among Aegilops and Triticum genomes. Phylogenetic trees constructed by using either LMW-i or the combination of LMW-m and LMW-s, as well as analysis of all the three types of LMW-GS genes together, demonstrated that the C and U genomes were closely related to the A genome, whereas the N and M genomes were closely related to the D genome. Our results support previous findings that the A genome was derived from Triticum uratu, the B genome was from Aegilops speltoides, and the D genome was from Aegilops tauschii. In addition, phylogenetic relationships among different genomes analysed in this study support the concept that Aegilops is not monophyletic.
Commuting mode choice in the context of travel demand management (TDM) policies: an empirical investigation in Edmonton, Alberta
Authors: Zaman Hamid , Habib Khandker M. Nurul
Published: April 2011

Travel demand management (TDM) for achieving sustainability is now considered one of the most important aspects of transportation planning and operation. It is now a well known fact that excessive use of private car results inefficient travel behaviour. So, from the TDM perspective, it is of great importance to analyze travel behaviour for improving our understanding on how to influence people to reduce car use and choose more sustainable modes such as  carpool, public transit, park & ride, walk, bike etc. This study attempts an in-depth analysis of commuting mode choice behaviour using a week-long commuter survey data set collected in the City of Edmonton. Using error correlated nested logit model for panel data, this study investigates sensitivities of various factors including some specific TDM policies such as flexible office hours, compressed work week etc. Results of the investigation provide profound understanding and guidelines for designing effective TDM policies.
Sapling age structure and growth series reveal a shift in recruitment dynamics of sugar maple and American beech over the last 40 years
Authors: Gravel Dominique , Beaudet Marilou , Messier Christian
Published: April 2011

Northern hardwoods have undergone a marked change in their dynamics, with American beech ( Fagus grandifolia Ehrh.) increasing in abundance relative to sugar maple ( Acer saccharum Marsh.). This study aims to better understand this sudden shift in recruitment dynamics. We performed an extensive analysis of the age structure, radial growth pattern, and release history on >700 saplings from 34 mature maple–beech stands of southern Quebec. We found (i) that the sapling age structures showed a progressive decrease in the establishment of maple relative to beech starting about 40 years ago, (ii) a change in the species growth hierarchy that started in the 1980s due to increasing radial growth of beech, (iii) that this growth trend is negligible for both maple and beech when we account for size and suppression status, and finally (iv) that the growth trend appears to be independent of present soil conditions. These results contrast with previous studies conducted at the adult stage that reported a growth decline for maple. We conclude that this change in recruitment dynamics is not related to growth, and consequently, further studies investigating this phenomenon should concentrate on establishment and survival.
Predicting site index from climatic, edaphic, and stand structural properties for seven plantation-grown conifer species in Quebec
Authors: Beaulieu Jean , Raulier Frédéric , Prégent Guy , Bousquet Jean
Published: April 2011

Models were built to relate site index to biophysical variables and stand structure for seven conifer species grown in plantation. Reduced models without stand structure were also derived to allow the prediction of site index even when information on the stand is unavailable. Biophysical variables tested were degree-days, aridity, summer precipitation, vapour pressure deficit, and soil water-holding capacity. The stand structure was accounted for using a Shannon evenness index of diameter at breast height distribution. Both full and reduced models had low to moderate R2 values and were slightly biased for most of the species. The results indicate that while correlations between phytometric and biophysical site indices are rather weak, those between plantation yield predicted using both indices and volume observed in the field are reasonably high (above 0.80). The biophysical site index models derived in this study could be used for strategic planning to estimate plantation yield or allowable cut for each of the seven conifer species.
Temporal aspects ofQuercus rubradecline and relationship to climate in the Ozark and Ouachita Mountains, Arkansas
Authors: Haavik L.J. , Stahle D.W. , Stephen F.M.
Published: April 2011

Extreme climate events are frequently important factors associated with episodes of forest decline. A recent oak decline event and concurrent outbreak of a native wood-boring beetle, the red oak borer ( Enaphalodes rufulus (Haldeman)), occurred throughout Arkansas Ozark and Ouachita Mountains. To investigate the role of drought and stand maturity on northern red oak ( Quercus rubra L.) decline, we analyzed tree-ring growth patterns and their relationships to climate from 815 live and 161 recently dead Q. rubra. While younger Q. rubra exhibited faster growth rates and stronger climate relationships than older Q. rubra, some individuals within all stands that originated >60 years ago were susceptible to growth decline or mortality. A significant growth interaction occurred among the three age classes identified where currently healthy Q. rubra were initially growing at slower decadal rates than currently declining or recently dead Q. rubra and later transitioned to higher growth rates than the others. These differences appear to be related to carbon allocation patterns towards rapid aboveground and (or) belowground growth early in development that led to later decline and (or) mortality. Decline in growth and weakening tree growth – climate relationships appeared to be initiated by an unusually severe and sustained drought in the early 1950s.
Forest transformation resulting from an exotic pathogen: regeneration and tanoak mortality in coast redwood stands affected by sudden oak death
Authors: Ramage Benjamin S. , O’Hara Kevin L. , Forrestel Alison B.
Published: April 2011

Sudden oak death is dramatically altering forests throughout coastal California, but little is known about the communities that are assembling in affected areas. This emerging disease, caused by the exotic pathogen Phytophthora ramorum (S. Werres, A.W.A.M. de Cock), has had especially severe effects on tanoak ( Notholithocarpus densiflorus (Hook. & Arn.) Manos, Cannon & S.H. Oh), a broadleaf evergreen that is abundant in forests dominated by coast redwood ( Sequoia sempervirens (D.Don) Endl.). Tanoak, a valuable food source to numerous wildlife species, is unlikely to successfully regenerate in diseased areas, and thus, affected redwood forests are transitioning to a novel state. In this study, to predict which species might replace tanoak, we investigated regeneration patterns in heavily impacted stands in Marin County, California. Our main findings were as follows: (i) despite reductions in canopy cover, there is no evidence that any species other than tanoak has exhibited a regenerative response to tanoak mortality, (ii) the regeneration stratum was dominated by redwood and tanoak (other tree species were patchy and (or) scarce), and (iii) some severely affected areas lacked sufficient regeneration to fully re-occupy available growing space. Our results indicate that redwood is likely to initially re-occupy the majority of the ground relinquished by tanoak, but also provide evidence that longer-term trajectories are unresolved, and may be highly responsive to management interventions.
Patterns of pine regeneration following a large, severe wildfire in the mountains of southern California
Authors: Franklin Janet , Bergman Erin
Published: April 2011

We examined establishment patterns of pines following a large, severe wildfire in the Peninsular Ranges of southern California, USA. The October 2003 Cedar Fire caused 98% pine mortality. In this study, we asked (i) where did seedlings establish and survive in formerly forested areas of the Cuyamaca Mountains 5 years following the high severity fire and (ii) what factors were associated with the spatial pattern of seedling establishment? Factors analyzed were pre-fire vegetation type, fire severity, post-fire vegetation characteristics, topography (slope, aspect, and elevation), and mapped soil type. We used a unique belt-transect survey method following the existing trail network that resulted in a representative sample of post-fire environments. Almost 1300 100 m × 20 m quadrats were searched in 2008–2009, one third of which supported juvenile pines. Regeneration primarily consisted of Coulter pine ( Pinus coulteri D. Don), a weakly serotinous pine that was establishing at densities of 5–2320/ha on half of the quadrats where it had occurred pre-fire. Pinus coulteri regenerated in areas burned at high severity where pre-fire pine cover was high and its abundance was positively associated with higher elevation and cover of bare soil. In contrast, minimal regeneration of nonserotinous pines occurred patchily in areas that were not severely burned.
COSMOLOGICAL IMPLICATIONS OF CONFORMAL FIELD THEORY
Authors: NESBET ROBERT K.
Published: April 2011

Requiring all massless elementary fields to have conformal scaling symmetry removes the conflict between gravitational theory and the quantum theory of elementary particles and fields. Extending this postulate to the scalar field of the Higgs model, dynamical breaking of both gauge and conformal symmetries determines parameters for the interacting fields. In uniform isotropic geometry a modified Friedmann cosmic evolution equation is derived with nonvanishing cosmological constant. Parameters determined by numerical solution are consistent with empirical data for redshifts z ≤ z* = 1090, including luminosity distances for observed type Ia supernovae and peak structure ratios in the cosmic microwave background (CMB). The theory does not require dark matter.
PERTURBATION STABLE CONDITIONAL ANALYTIC MONTE-CARLO PRICING SCHEME FOR AUTO-CALLABLE PRODUCTS
Authors: FRIES CHRISTIAN P. , JOSHI MARK S.
Published: April 2011

In this paper, we present a generic method for the Monte-Carlo pricing of (generalized) auto-callable products (aka. trigger products), i.e., products for which the payout function features a discontinuity with a (possibly) stochastic location (the trigger) and value (the payout).

The Monte-Carlo pricing of products with discontinuous payout is known to come with a high Monte-Carlo error. The numerical calculation of sensitivities (i.e., partial derivatives) of such prices by finite differences gives very noisy results, since the Monte-Carlo approximation (being a finite sum of discontinuous functions) is not smooth. Additionally, the Monte-Carlo error of the finite-difference approximation explodes as the shift size tends to zero.

Our method combines a product specific modification of the underlying numerical scheme, which is to some extent similar to an importance sampling and/or partial proxy simulation scheme and a reformulation of the payoff function into an equivalent smooth payout.

From the financial product we merely require that hitting of the stochastic trigger will result in an conditionally analytic value. Many complex derivatives can be written in this form. A class of products where this property is usually encountered are the so called auto-callables, where a trigger hit results in cancellation of all future payments except for one redemption payment, which can be valued analytically, conditionally on the trigger hit.

From the model we require that its numerical implementation allows for a calculation of the transition probability of survival (i.e., non-trigger hit). Many models allows this, e.g., Euler schemes of Itô processes, where the trigger is a model primitive.

The method presented is effective across a large range of cases where other methods fail, e.g. small finite difference shift sizes or short time to trigger reset (approaching maturity); this means that a practitioner can use this method and be confident that it will work consistently.

The method itself can be viewed as a generalization of the method proposed by Glasserman and Staum (2001), both with respect to the type (and shape) of the boundaries, as well as, with respect to the class of products considered. In addition we explicitly consider the calculation of sensitivities.
SPECTROSCOPIC STUDIES ON Ag/PVA NANOCOMPOSITE THIN FILMS PREPARED BY THERMAL ANNEALING PROCESS
Authors: SAIKIA RAJIB , GOGOI P. , BARUA P. K. , DATTA PRANAYEE
Published: April 2011

In this paper, a systematic spectroscopic analysis on silver–polyvinyl alcohol ( Ag /PVA) nanocomposite thin films is reported. Ag /PVA nanocomposite thin films fabricated by thermal annealing process are shown to exhibit a strong localized surface plasmon resonance (LSPR) at wavelength around 400 nm. The effects of different fabricating parameters on the absorbance and spectral position of LSPR are also investigated. The particle sizes calculated from Mie light scattering theory are found to agree with the values obtained from SEM characterization.
SELF-ASSEMBLY OF CdSe NANOROD ARRAYS BY ELECTROPHORETIC DEPOSITION OF CdSe NANOPARTICLES
Authors: VIGNEASHWARI B. , SATYANARAYANA S. V. M.
Published: April 2011

The formation of arrays of CdSe nanorods and their fractal aggregates by a self-assembly of spherical nanoparticles of CdSe is achieved using electrophoretic deposition (EPD). Notably, neither templates nor complexating agents are used during the deposition. Also, deposits have not been subjected to any post-heat treatment. EPD turns out to be a low-cost, pollution-free, and a highly portable technique among all the other deposition techniques known. The size, crystallinity, composition, and shape of the nanoparticles as well as the deposits were analyzed using XRD, TEM, and EDAX. Mechanisms for different stages of deposition, and self-assembly is inferred by a detailed analysis of surface morphology of nanostructural deposits using HRSEM and AFM studies. Fractal nature of the deposits is quantified by computing fractal dimension of a typical portion of a deposited film.
LOW TEMPERATURE SYNTHESIS AND ELECTRONIC PROPERTIES OF NTC TEMPERATURE SENSOR SPINEL-TYPE OXIDES NANOPOWDERS
Authors: HOSSEINI S. M. , SHOHANY B. GHANBARI , AZAD N. , KOMPANY A.
Published: April 2011

NiCoxMn2-xO4(x = 0.4, 0.8, 1.2, 1.6) thermistor with nanopowders have been synthesized by the auto-combustion method at low temperatures. The size and morphology of the calcinated powders have been investigated using XRD and TEM techniques. The average particle size was estimated to be about 65 nm in diameter with the cubic and cubic + tetragonal phases for low and high cobalt concentrations, respectively. The grain size of NTC ceramics sintered at 1200°C is verified with scanning electron microscopy (SEM) images. Upon increasing the cobalt concentration, the grain size of NTC samples increases from about 2 μm to a few μm in size.

The formation of spinel structure of powders has been studied by Fourier transform infrared (FTIR) spectroscopy. An ab initio calculation of electronic properties of NiCo0.8Mn1.2O4using full potential of the linear augmented plane wave (FP-LAPW) method has been performed. The results indicate that only the 3d- Mn orbitals play an important role in the conduction mechanism. The dependency of material resistivity constant (B) and temperature coefficient (α) have been measured.
LANDE'S g VALUE IN QUANTUM DOTS IN AlxGa1-xAs
Authors: SHRIVASTAVA KESHAV N.
Published: April 2011

The light-hole g value in Al x Ga 1-x As is found to show scaling behavior as a function of quantum well width, g ≃( well width )-β with β ≃ 0.3. When x is varied to change the Ga concentration there is a critical value of the concentration of 1 - x0 = 0.88, at which the g value vanishes, g⊥ = 0. There is a scaling behavior, g⊥ = 2[1 - (1 - x)/(1 - xo)]y. The g⊥ data varies from about -0.42 for x = 0 to 0.60 for x = 0.374. Hence, the large variations in the g values are due to a phase transition. Similar results for InAs are also discussed. The contribution to the g value arising from the Calogero-type potential is deduced, which gives rise to wave functions in the form of Jack polynomials.
SPIN-POLARIZATION-DEPENDENT TRANSPORT IN GRAPHENE NANORIBBON WITH A VACANCY
Authors: LIU CHUN-MEI , LIU NIAN-HUA , LIU ZHENG-FANG , AN LI-PING
Published: April 2011

By using the first-principles density functional theory combining with the nonequilibrium Green’s function techniques, we investigate the electronic structure and the spin-polarization-dependent electronic transport of zigzag graphene nanoribbons (ZGNR) with a defect of vacancy. The total energy of the graphene ribbons corresponding to different vacancy locations is calculated to analyze the stability of the structures. It is found that the existence of a vacancy causes a significant change in the electronic band gap. The electronic band and the transport become spin-polarization-dependent. The calculated I–V characteristic shows that the spin-polarization-dependent effect can be enhanced under a finite bias voltage.
NOISE AND SEASONAL EFFECTS ON THE DYNAMICS OF PLANT–HERBIVORE MODELS WITH MONOTONIC PLANT GROWTH FUNCTIONS
Authors: KANG YUN , ARMBRUSTER DIETER
Published: April 2011

We formulate general plant–herbivore interaction models with monotone plant growth functions (rates). We study the impact of monotone plant growth functions in general plant–herbivore models on their dynamics. Our study shows that all monotone plant growth models generate a unique interior equilibrium and they are uniform persistent under certain range of parameters values. However, if the attacking rate of herbivore is too small or the quantity of plant is not enough, then herbivore goes extinct. Moreover, these models lead to noise sensitive bursting which can be identified as a dynamical mechanism for almost periodic outbreaks of the herbivore infestation. Montone and non-monotone plant growth models are contrasted with respect to bistability and crises of chaotic attractors.
NON-NEWTONIAN FLOWS IN CONTRACTING/EXPANDING BLOOD VESSELS: A THEORETICAL STUDY
Authors: MISRA J. C. , DANDAPAT S. , ADHIKARY S. D.
Published: April 2011

The paper deals with a problem related to the flow of blood in vessels. It is known that physiological pumps produce flow by alternate contraction and expansion of the vessel. When muscles start squeezing the vessel wall, the valve at the upstream end gets closed and that at the downstream end becomes open. As a result of this, blood is pumped out in the downstream direction. During systole, when the blood in the left ventricle is forced into the aorta, the mitral valve becomes closed, while the atrioventricular valve becomes open. In a situation such as this, the left ventricle takes the form of a vessel with one end closed. In order to study such a situation, a model has been developed here that consists of a fluid-filled long cylindrical pipe with one end closed by a compliant membrane (that prevents the axial motion of the fluid, leaving radial motion completely unrestricted). An approximate solution of the Navier–Stokes equation for the flow of a second-order fluid is presented. The derived analytical expressions are computed numerically. The computed values indicate that if the Reynolds number of the flow is low, the effect of fluid viscoelasticity appears in higher-order terms.
SOLITONS IN ALPHA-HELIX PROTEINS BY HE'S VARIATIONAL PRINCIPLE
Authors: BISWAS ANJAN , MILOVIC DANIELA , MILIC DEJAN
Published: April 2011

This paper studies the dynamics of solitons due to solitons in α-helix proteins. The analysis is going to be carried out by the aid of He's semi-inverse variational principle. The constraint relation between the soliton parameters will also be determined in order for the soliton to exist.
BRITTON CHANCE IN MEMORIAM
Authors: MILDVAN ALBERT S.
Published: April 2011

This short note covers some of my favorite scientific accomplishments of Britton Chance.
BUSINESS GROUP AFFILIATION AND LOCATION OF INDIAN FIRMS' FOREIGN ACQUISITIONS
Authors: PRADHAN JAYA PRAKASH , SINGH NEELAM
Published: April 2011

This study examines the determinants of host-location of cross-border acquisitions by Indian Business Group (BG)-affiliates and other firms during 2000–2008. Our empirical estimates indicate the general attraction of host country market-size and double-taxation-avoidance treaty. However, unlike the standalone firms, the acquisition-location of BG-affiliates is favourably influenced by the host growth rate and bilateral investment treaty, apparently drawn to distant nations, and not significantly affected by the cultural proximity. The host's share of home exports affects relatively more the acquisition-location of standalone firms. Thus the derived resources/ parental networks of BG-affiliated emerging market multinational enterprises influence their outward-FDI locational pattern.
ASIAN MONETARY UNIT (AMU) AS A SURVEILLANCE INDICATORS FOR REGIONAL MONETARY COOPERATION
Authors: OGAWA EIJI , SHIMIZU JUNKO
Published: April 2011

Ogawa and Shimizu (2005) proposed an Asian Monetary Unit (AMU), which is a common currency basket composed of ASEAN plus three Asian currencies, and AMU Deviation Indicators (AMU DIs), which indicates deviations of each Asian currency in terms of the AMU compared to the benchmark rate. In this paper, we use daily and monthly data of AMU and AMU DIs to examine their usefulness as a surveillance indicator for monetary cooperation in Asia. We find that an AMU peg system stabilizes the trade-weighted exchange rates within Asia and that AMU DIs warn of misalignments of and between Asia currencies.
FROM GROWTH REGRESSIONS TO SYSTEMS OF EQUATIONS
Authors: ZIESEMER THOMAS H. W.
Published: April 2011

The literature on the effects of aid and remittances as a share of GDP on growth of the GDP per capita has placed much emphasis on growth regressions thereby emphasising only the direct effects on growth. In order to get the total effect one has to capture the indirect ones too and integrate them with the direct effects. To do so we integrate all equations into a dynamic system and run a baseline simulation. We compare several scenarios — doubling aid, cutting remittances to half, and stopping net migration — to the baseline simulation for all variables.
ERK is involved in EGF-mediated protection of tight junctions, but not adherens junctions, in acetaldehyde-treated Caco-2 cell monolayers
Authors: Samak G. , Aggarwal S. , Rao R. K.
Published: April 2011

The role of mitogen-activated protein kinases (MAPK) in the mechanism of EGF-mediated prevention of acetaldehyde-induced tight junction disruption was evaluated in Caco-2 cell monolayers. Pretreatment of cell monolayers with EGF attenuated acetaldehyde-induced decrease in resistance and increase in inulin permeability and redistribution of occludin, zona occludens-1 (ZO-1), E-cadherin, and β-catenin from the intercellular junctions. EGF rapidly increased the levels of phospho-ERK1/2, phospho-p38 MAPK, and phospho-JNK1. Pretreatment of cell monolayers with U-0126 (inhibitor of ERK activation), but not SB-202190 and SP-600125 (p38 MAPK and JNK inhibitors), significantly attenuated EGF-mediated prevention of acetaldehyde-induced changes in resistance, inulin permeability, and redistribution of occludin and ZO-1. U-0126, but not SB-202190 and SP-600125, also attenuated EGF-mediated prevention of acetaldehyde effect on the midregion F-actin ring. However, EGF-mediated preservation of junctional distribution of E-cadherin and β-catenin was unaffected by all three inhibitors. Expression of wild-type or constitutively active MEK1 attenuated acetaldehyde-induced redistribution of occludin and ZO-1, whereas dominant-negative MEK1 prevented EGF-mediated preservation of occludin and ZO-1 in acetaldehyde-treated cells. MEK1 expression did not alter E-cadherin distribution in acetaldehyde-treated cells in the presence or absence of EGF. Furthermore, EGF attenuated acetaldehyde-induced tyrosine-phosphorylation of occludin, ZO-1, claudin-3, and E-cadherin. U-0126, but not SB-202190 and SP-600125, prevented EGF effect on tyrosine-phosphorylation of occludin and ZO-1, but not claudin-3, E-cadherin, or β-catenin. These results indicate that EGF-mediated protection of tight junctions from acetaldehyde requires the activity of ERK1/2, but not p38 MAPK or JNK1/2, and that EGF-mediated protection of adherens junctions is independent of MAPK activities.
Sepsis impairs alveolar epithelial function by downregulating Na-K-ATPase pump
Authors: Berger Gidon , Guetta Julia , Klorin Geula , Badarneh Reem , Braun Eyal , Brod Vera , Saleh Niroz Abu , Katz Adriana , Bitterman Haim , Azzam Zaher S.
Published: April 2011

Widespread vascular endothelial injury is the major mechanism for multiorgan dysfunction in sepsis. Following this process, the permeability of the alveolar capillaries is augmented with subsequent increase in water content and acute respiratory distress syndrome (ARDS). Nevertheless, the role of alveolar epithelium is less known. Therefore, we examined alveolar fluid clearance (AFC) using isolated perfused rat lung model in septic rats without ARDS. Sepsis was induced by ligating and puncturing the cecum with a 21-gauge needle. AFC was examined 24 and 48 h later. The expression of Na-K-ATPase proteins was examined in type II alveolar epithelial cells (ATII) and basolateral membrane (BLM). The rate of AFC in control rats was 0.51 ± 0.02 ml/h (means ± SE) and decreased to 0.3 ± 0.02 and 0.33 ± 0.03 ml/h in 24 and 48 h after sepsis induction, respectively ( P < 0.0001). Amiloride, significantly decreased AFC in sepsis; conversely, isoproterenol reversed the inhibitory effect of sepsis. The alveolar-capillary barrier in septic rats was intact; therefore the finding of increased extravascular lung water in early sepsis could be attributed to accumulation of protein-poor fluid. The expression of epithelial sodium channel and Na-K-ATPase proteins in whole ATII cells was not different in both cecal ligation and puncture and control groups; however, the abundance of Na-K-ATPase proteins was significantly decreased in BLMs of ATII cells in sepsis. Early decrease in AFC in remote sepsis is probably related to endocytosis of the Na-K-ATPase proteins from the cell plasma membrane into intracellular pools, with resultant inhibition of active sodium transport in ATII cells.
Leukocyte Complexity Predicts Breast Cancer Survival and Functionally Regulates Response to Chemotherapy
Authors: DeNardo David G. , Brennan Donal J. , Rexhepaj Elton , Ruffell Brian , Shiao Stephen L. , Madden Stephen F. , Gallagher William M. , Wadhwani Nikhil , Keil Scott D. , Junaid Sharfaa A. , Rugo Hope S. , Hwang E. Shelley , Jirström Karin , West Brian L. , Coussens Lisa M.
Published: April 2011

Immune-regulated pathways influence multiple aspects of cancer development. In this article we demonstrate that both macrophage abundance and T-cell abundance in breast cancer represent prognostic indicators for recurrence-free and overall survival. We provide evidence that response to chemotherapy is in part regulated by these leukocytes; cytotoxic therapies induce mammary epithelial cells to produce monocyte/macrophage recruitment factors, including colony stimulating factor 1 (CSF1) and interleukin-34, which together enhance CSF1 receptor (CSF1R)–dependent macrophage infiltration. Blockade of macrophage recruitment with CSF1R-signaling antagonists, in combination with paclitaxel, improved survival of mammary tumor–bearing mice by slowing primary tumor development and reducing pulmonary metastasis. These improved aspects of mammary carcinogenesis were accompanied by decreased vessel density and appearance of antitumor immune programs fostering tumor suppression in a CD8+ T-cell–dependent manner. These data provide a rationale for targeting macrophage recruitment/response pathways, notably CSF1R, in combination with cytotoxic therapy, and identification of a breast cancer population likely to benefit from this novel therapeutic approach.

Significance: These findings reveal that response to chemotherapy is in part regulated by the tumor immune microenvironment and that common cytotoxic drugs induce neoplastic cells to produce monocyte/macrophage recruitment factors, which in turn enhance macrophage infiltration into mammary adenocarcinomas. Blockade of pathways mediating macrophage recruitment, in combination with chemotherapy, significantly decreases primary tumor progression, reduces metastasis, and improves survival by CD8+ T-cell–dependent mechanisms, thus indicating that the immune microenvironment of tumors can be reprogrammed to instead foster antitumor immunity and improve response to cytotoxic therapy. Cancer Discovery; 1(1); 54–67. ©2011 AACR.

This article is highlighted in the In This Issue feature, p. 4
Epidemiology—Found in Translation
Authors: Spitz Margaret R. , Caporaso Neil E. , Freedman Andrew N.
Published: April 2011

We highlight the value of carefully designed observational epidemiologic analyses in translating basic science discoveries to clinical application and in providing the impetus for exploring underlying mechanisms for observed associations. Coupling epidemiologic data with an in vitro screen of commonly used therapeutic agents may identify novel applications for further clinical testing. Cancer Discovery; 1(1); 21–2. ©2011 AACR.

Commentary on Platz et al., p. 68
KRAS Oncogene Rearrangements and Gene Fusions: Unexpected Rare Encounters in Late-Stage Prostate Cancers
Authors: Edgren Henrik , Kangaspeska Sara , Kallioniemi Olli
Published: April 2011

Wang and colleagues identify a fusion between UBE2L3 and KRAS in a subset of metastatic prostate cancers. Cancer Discovery; 1(1); 12–3. ©2011 AACR.

Commentary on Wang et al., p. 35
Stumbling Blocks on the Path to Personalized Medicine in Breast Cancer: The Case of PARP Inhibitors for BRCA1/2-Associated Cancers
Authors: Balmaña Judith , Domchek Susan M. , Tutt Andrew , Garber Judy E.
Published: April 2011

The popular vision for the future of oncology includes the rational design of therapies inhibiting specific targets, for which development would be less expensive and the chance of success greater because the agent, the target, and a population predicted to benefit maximally would be known from the outset. In the breast cancer arena, successful targeted therapies have entered clinical practice. Recently, patients with BRCA-associated cancers have been identified as eligible for novel investigational therapies targeting their genetic deficiency. Preclinical data, phase I results, and 2 phase II proof-of-concept studies support the continued development of PARP inhibitors, either as single agents or in combination with specific cytotoxic drugs in this setting. In this article, we provide a brief review of current developments concerning PARP inhibitors in BRCA-associated cancers and express concerns about challenges to further development.

Summary: PARP inhibitors may represent a new and promising targeted therapy for patients with BRCA1/2-associated cancer. In this review we summarize the main challenges in the clinical development of these agents. Cancer Discovery; 1(1); 29–34. ©2011 AACR.