bluuebunny/crossref_metadata_2025 huggingface dataset:
Reducing drag penalty in the three-dimensional supersonic biplane
Authors: Yonezawa M , Obayashi S
Published: July 2009

The two-dimensional (2D) supersonic biplane is well known for its shock wave cancellation effect and zero wave drag at supersonic speed. Nonetheless, in a three-dimensional (3D) setting, this favourable shock wave interaction becomes disturbed in the Mach cone regions at the wing tips of the supersonic biplane, which results in a severe drag penalty near the wing tips. However, this can be alleviated by appropriately designing the planform of the biplane. This study was performed to investigate the patterns of the 3D shock wave interaction using computational fluid dynamics by considering the 3D supersonic biplane with different planforms. The drag was shown to become large when the wing has a high sweepback angle, and it became small when the wing has a small taper ratio. However, an excessively low taper ratio could also lead to a drag greater than that of the rectangular supersonic biplane. It was found that the low drag 3D supersonic biplane has a small sweepback angle and an adequate taper ratio, which results in the vertex line becoming almost perpendicular to the freestream. Thus, in the design of the low drag 3D supersonic biplane, it is important to take into consideration the trade-off between the drag reduction at the mid-span section and the drag penalty near the wing tip and the wing root.
Quantifying sway through surface deflection patterns: A novel approach using distributive tactile sensing
Authors: Elliott M T , Petra I , Ma X-H , Brett P N , Holding D J
Published: July 2009

This paper describes an experiment that extends the distributive sensing approach to identify the three-dimensional location of an object in constant motion. Distributive sensing has previously been successful in the identification of size and location of statically placed objects. Here, a novel system is developed to measure balance or sway in patients. The experimental set-up consisted of a pendulum structure positioned on a supported steel plate. Three low-cost deflection sensors were positioned under the plate with the resulting signals used as inputs to a neural network implemented on a field-programmable gate array. The results show that the embedded system can accurately track the pendulum position in real time with a mean tracking error of around 6 per cent in all three dimensions. This evidence indicates that the technique is sufficiently sensitive and could be implemented in a pragmatic configuration for discriminating between balance and sway.
Controlling force variations during soft-tissue grasping
Authors: Alja'afreh T
Published: July 2009

This paper develops a mechatronic grasper that can be used to investigate a preliminary experiment of a simple model-independent approach to control soft-tissue grasping based on, first, measurement of the total tangential grasp force and, second, discrimination of relaxation and frictional forces by imposing a limited basis set of grasper motions. The main motivation for this work is that tissue grasping is an important component of surgical procedures. However, there is a major criterion which should be achieved: maintaining grasp stability while avoiding damage due to excessive grip force. Thus, the automation of grasping force control requires a controller to apply grasping forces just sufficient to maintain grasp stability. This task is complicated by the serially connected dynamics of grasp friction and tissue relaxation.
Colour flow and motion imaging
Authors: Evans D H
Published: July 2009

Colour flow imaging (CFI) is an ultrasound imaging technique whereby colour-coded maps of tissue velocity are superimposed on grey-scale pulse-echo images of tissue anatomy. The most widespread use of the method is to image the movement of blood through arteries and veins, but it may also be used to image the motion of solid tissue. The production of velocity information is technically more demanding than the production of the anatomical information, partly because the target of interest is often blood, which backscatters significantly less power than solid tissues, and partly because several transmit—receive cycles are necessary for each velocity estimate. This review first describes the various components of basic CFI systems necessary to generate the velocity information and to combine it with anatomical information. It then describes a number of variations on the basic autocorrelation technique, including cross-correlation-based techniques, power Doppler, Doppler tissue imaging, and three-dimensional (3D) Doppler imaging. Finally, a number of limitations of current techniques and some potential solutions are reviewed.
Substituent Effect of Imino-O-arenesulfonates, a Coupling Partner in Suzuki–Miyaura Reaction for Substitution of the Pyrazine Ring: A Study for the Synthesis of Coelenterazine Analogs
Authors: Makarasen Arthit , Kuse Masaki , Nishikawa Toshio , Isobe Minoru
Published: July 2009

Amino(aryl)pyrazines, a key intermediate in the synthesis of coelenterazine and its analogs, can be prepared in excellent yields by utilizing imino-O-tosylates in the Suzuki–Miyaura reaction. These imino-O-tosylates serve as a substitute for the corresponding imino-O-triflates, which are sometimes too unstable to be stored during the optimization of the reaction conditions. Aryltrifluoroborates, a coupling partner, worked well when arylboronic acids or arylboronate esters were less reactive. Aryltrifluoroborates also worked well when containing an electron-donating group attached to the aromatic ring. The study of the substituent effect of imino-O-arenesulfonates demonstrated a major difference in the rate of the reactions when changing from electron-donating groups to electron-withdrawing groups at the para position of arenesulfonates. Imino-O-arenesulfonate containing a para-bromo substituent only gave the desired coupling product leaving the para substituent of arenesulfonate untouched.
Business Unit Reorganization and Innovation in New Product Markets
Authors: Karim Samina
Published: July 2009

This paper empirically examines how business unit reorganization affects innovation, and explores how the learning process may mediate this relationship. Unit reorganization is the creation, deletion, or recombination of business units within a firm. Innovation is radical and involves product market entry by a firm into markets in which it was not previously active. I test competing hypotheses that predict either a U-shape or inverted U-shape relationship between reorganization and innovation to determine whether and how learning occurs in the presence of unit-level structural change. Theoretical support is drawn from literature on dynamic capabilities and organizational learning. The sample studied is 250 medical firms belonging to the pharmaceutical, healthcare-service, and medical-device industries, studied over a 20-year period. The findings are twofold. First, reorganization is found to exhibit a U-shape relationship with innovation, supporting learning arguments that stress the importance of experiencing a cohort of multiple events. Second, only reorganization experiences within a current period affect future innovation; past experiences do not impact future innovation, implying that firms may face constraints in organizational memory. The study concludes by exploring the structural origin (i.e., from internal, acquired, or recombined units) of innovative activity within firms.
Aptamer-Based Regionally Protected PCR for Protein Detection
Authors: Lin Jun Sheng , McNatty Kenneth P
Published: July 2009

Background: DNA aptamers are single-stranded nucleotide sequences that bind specifically to target molecules. By combining the advantages of PCR for amplifying specific DNA sequences and aptamer technology, we have developed a new strategy to detect target molecules such as proteins.

Methods: Ovine follicle-stimulating hormone α subunit (oFSHα) was used as the model protein to generate a specific DNA aptamer via an in vitro evolutionary process. A targeted regional-mapping approach and a target-capturing assay were used to identify the binding region on the aptamer molecule. In the detection assay, referred to as “aptamer-based regionally protected PCR” (ARP-PCR), the aptamer was allowed to bind to the target protein in solution before digestion with DNase I. The region of the aptamer bound to the target was protected from DNase I cleavage. The target-binding region of the aptamer protected from the enzymatic treatment was then amplified by the PCR.

Results: Aptamers against oFSHα were generated. Six sequences of 20 selected aptamer clones were identical. This aptamer sequence was divided into 4 regions according to the aptamer’s secondary structure. From examination of the target-binding ability of each region, we determined the specific binding region, for which primers were designed. With the aptamer and primers to detect oFSHα by means of the ARP-PCR method, we were able to detect the target protein at concentrations as low as 10−14 mol/L.

Conclusions: Combining the use of a DNA aptamer with the PCR is a potentially useful analytic tool for detection of proteins at low concentrations. .
Do Switching Costs Make Markets Less Competitive?
Authors: Dubé Jean-Pierre , Hitsch Günter J. , Rossi Peter E.
Published: July 2009

The conventional wisdom in economic theory holds that switching costs make markets less competitive. This article challenges this claim. The authors formulate an empirically realistic model of dynamic price competition that allows for differentiated products and imperfect lock-in. They calibrate this model with data from frequently purchased packaged goods markets. These data are ideal in the sense that they have the necessary variation to identify switching costs separately from consumer heterogeneity. Equally important, consumers exhibit inertia in their brand choices, a form of psychological switching cost. This makes the results applicable to the broad range of products that are distinctly identified (i.e., branded) rather than just to products for which there is a product adoption cost or explicit switching fee. In the simulations, prices are as much as 18% lower with than without switching costs. More important, equilibrium prices do not increase even in the presence of switching costs that are of the same order of magnitude as product price.
Perception Spillovers across Competing Brands: A Disaggregate Model of how and When
Authors: Janakiraman Ramkumar , Sismeiro Catarina , Dutta Shantanu
Published: July 2009

Drawing on the accessibility–diagnosticity framework and previous literature on branding and order of entry, the authors hypothesize that perception spillovers can also occur across directly competing products that do not share a common brand name. The authors suggest two mechanisms (prior perception spillover and dynamic perception spillover) and one moderating variable (product/brand similarity). To test for spillovers across competing brands, the authors develop a structural Bayesian learning model and estimate it using prescription choice and marketing communication data from a panel of physicians. From their model results, the authors find evidence of prior and dynamic perception spillovers across competing brands only when brands are sufficiently similar. In contrast, they find no evidence of spillover effects across brands that are highly dissimilar. Finally, several policy experiments illustrate the strength and significance of competitive spillovers for product diffusion, and from the results, the authors derive strategic implications for order-of-entry effects and the entry of “me-too” products.
Zur Entwicklung von Verbzweit im Fragesatz. Die Evidenz im Althochdeutschen
Authors: Petrova Svetlana , Solf Michael
Published: July 2009

The paper explores the syntax of direct questions in Old High German (OHG) with particular reference to the placement of the finite verb and the interrogative element. It evaluates the complete OHG corpus and analyses the word order patterns taking into account the relevant loan-syntactic or metrical factors. The study shows that there is secure evidence allowing to retrace the emergence of V1 and V2 as the core patterns in alternative and constituent questions in modern German. In addition, the relation between the establishment of the V2-pattern in interrogatives and the consolidation of the V2-rule in main declarative clauses is discussed.
Congenital cataract with de novo balanced reciprocal t(3;13) (q23;q12) translocation in a newborn
Authors: Dilli Dilek , Oğuz Şerife Suna , Dilmen Uğur , Çakar Esra Sükran , Tunay Zühal Özen , Tök Özlem , Acar M. Akif
Published: July 2009

No abstract available
The effect of maternal obesity on the course of labor
Authors: Verdiales Maribelle , Pacheco Carlos , Cohen Wayne R.
Published: July 2009

Aim: To determine whether maternal obesity is associated with dysfunctional labor patterns.

Methods: In a case-control design we compared the graphic labor patterns of a group of 105 very obese subjects [body mass index (BMI) >35 kg/m2] with those of 113 lean controls (BMI<26 kg/m2). All entered spontaneous labor at term. Cases with birth weights >4 kg, diabetes mellitus, hypertension and prior cesarean delivery were excluded.

Results: The obese group had a significantly higher frequency of arrest of dilatation (17.6 vs. 5.2%; P=0.005).

Conclusions: Maternal obesity is associated with active phase labor dysfunction, specifically arrest of dilatation.
Disparity in circulating adiponectin multimers between term and preterm infants
Authors: Siahanidou Tania , Margeli Alexandra , Garatzioti Maria , Davradou Maria , Apostolakou Filia , Papassotiriou Ioannis , Mandyla Helen
Published: July 2009

Aims: To study circulating levels and distribution of adiponectin multimers [low molecular weight (LMW)-, medium molecular weight (MMW)- and high molecular weight (HMW)-adiponectin] in preterm and full-term infants.

Methods: Total serum adiponectin and its multimers were measured in 40 healthy infants at the age of one month and associations with anthropometric parameters [body weight and length, body mass index (BMI)], weight gain and metabolic indices (glucose, insulin) were examined. Twenty of the infants were born preterm (gestational age 33.2±1.6 weeks).

Results: LMW-adiponectin level and its fractional ratio to total adiponectin were significantly higher in full-term than in preterm infants (P<0.001 and P<0.01, respectively), whereas, MMW-adiponectin level and its ratio were significantly lower (P=0.03 and P=0.01, respectively). HMW-adiponectin did not differ significantly between full-term and preterm infants and accounted for almost 60% of total adiponectin levels in both groups. HMW-adiponectin, but not MMW adiponectin or LMW adiponectin, correlated significantly with anthropometric measurements, similarly to total adiponectin; in addition, HMW adiponectin correlated significantly with weight gain.

Conclusions: HMW adiponectin is the most prevalent form in infants. Circulating levels and distribution of MMW- and LMW-adiponectin differ between full-term and preterm infants, but the role of these adiponectin multimers needs to be studied further.
Survival and major disability rate in infant born at 22–25 weeks of gestation
Authors: Dani Carlo , Poggi Chiara , Romagnoli Costantino , Bertini Giovanna
Published: July 2009

Our aim was to evaluate the literature on survival and major disability rate in preterm infants born at 22– 25 weeks of gestational age (GA). Thirty-three studies were identified and reviewed. Survival was lower in population-based studies (2% at 22, 13% at 23, 35% at 24, and 56% at 25 weeks) than in center-based study (15% at 22, 41% at 23, 58% at 24, and 74% at 25 weeks). The severe disability rate was slightly higher in population-based studies than in center-based studies at 23 (29 vs. 32%) and at 24 (30 vs. 27%) week of GA, whereas it was similar in population and center-based studies at 25 (21 vs. 22%) weeks of GA. Survival rate seems to improve with time, whereas the change of severe disability rate cannot be adequately evaluated due to the paucity of available data. We conclude that the survival of infants born at 22 weeks is still an uncommon event, whereas the survival of infants born at 23, and mostly at 24 and 25 weeks of GA is significant in the majority of studies.
Vanishing nuchal translucency syndrome
Authors: Basaran Ahmet , Deren Özgür
Published: July 2009

No abstract available
The clinical outcomes of late preterm infants: a multi-center survey of Zhejiang, China
Authors: Ma Xiaolu , Huang Chunxiang , Lou Shouzeng , Lv Qin , Su Weidong , Tan Jiarong , Wang Youcheng , Wang Xinxin , Wu Mingyuan , Xu Ting , Zhuang Manli , Du Lizhong , the Provincial Collaborative Study Group for Late-preterm In
Published: July 2009

Objective: To explore birth rate, delivery mode, medical problems, requirement of respiratory support, and acute outcomes of late preterm infants in Zhejiang province in eastern China.

Methods: Eleven tertiary hospitals were recruited. Clinical data of every nursery admission from January to December 2007 were collected and analyzed.

Results: During the study period, 44,362 infants were born with an overall preterm birth rate of 8.9%, and late preterm birth rate of 6.2%. Late preterm infants had higher cesarean section rate than the whole population (64.9% vs. 58.2%). One-fifth of the nursery admissions were late preterm infants, of whom, 63.8% were delivered by cesarean section. Respiratory distress (42.1%) was the most common medical problem of late preterm infants. Hyperbilirubinemia (17.6%), hypoglycemia (8.7%) and sepsis (5.9%) were also common. The first three primary diagnoses of respiratory distress included pneumonia (39.5%), transient tachypnea of newborn (TTN) (22.5%) and respiratory distress syndrome (RDS) (19.0%). Compared with term infants, late preterm infants with respiratory distress needed more respiratory support with nasal continuous positive airway pressure (nCPAP) (21.4% vs. 11.6%) or with a mechanical ventilator (15.4% vs. 11.0%), and also had higher in-hospital mortality (0.8% vs. 0.4%).

Conclusions: Late preterm infants are associated with very high cesarean section rate and have more medical problems and poorer short-term outcomes than term infants in China.
The importance of multidetector computed tomography in the vascular imaging
Authors: Halász Szabolcs , Puskás Tamás
Published: July 2009

A több detektorsoros spirál-CT-berendezések és a hozzájuk tartozó speciális rekonstrukciós szoftverek bevezetése lehetővé tette az erek jó minőségű CT-vizsgálatát.
Cél és módszerek:
A szerzők ismertetik a CT-angiográfiai vizsgálatok elvét, technikáját, amelyet az elmúlt három évben közel 700 saját betegükön végzett vizsgálataik eredményeivel, tapasztalataival egészítenek ki. Bemutatják a CT-angiográfia jelentőségét, valamint annak más vascularis képalkotó eljárások helyett vagy melletti alkalmazhatóságát.
Következtetések:
A CT-angiográfia gyors, noninvazív vizsgálati módszer, amellyel – önmagában vagy más vizsgálattal kiegészítve – pontos diagnózis állítható fel.
Nanosphere lithography of nanostructured silver films on thin-film silicon solar cells for light trapping
Authors: Ozturk Birol , Schiff Eric A , Zhao Hui , Guha Subhendu , Yan Baojie , Yang Jeff
Published: July 2009

Sparse arrays of evaporated silver nanodiscs were fabricated with nanosphere lithography (NSL) on glass substrates and on hydrogenated nanocrystalline silicon solar cells. The optical transmittance spectra for arrays on glass vary substantially with film thickness, and were reasonably consistent with previous work. The quantum efficiency spectra of hydrogenated nanocrystalline silicon solar cells show spectral shifts due to coupling of surface plasmons in the metal nanodiscs to the planar waveguide modes of the cells, with overall photocurrent enhancement up to 10%.
Defects in Hydrogenated Amorphous Silicon Carbide Alloys using Electron Spin Resonance and Photothermal Deflection Spectroscopy
Authors: Simonds Brian J. , Zhu Feng , Gallon Josh , Hu Jian , Madan Arun , Taylor Craig
Published: July 2009

Hydrogenated amorphous silicon carbide alloys are being investigated as a possible top photoelectrode in photoelectrochemical cells used for hydrogen production through water splitting. In order to be used as such, it is important that the effects of carbon concentration on bonding, and thus on the electronic and optical properties, is well understood. Electron spin resonance experiments were performed under varying experimental conditions to study the defect concentrations. The dominant defects are silicon dangling bonds. At room temperature, the spin densities varied between 1016 and 1018 spins/cm3 depending on the carbon concentration. Photothermal deflection spectroscopy, which is an extremely sensitive measurement of low levels of absorption in thin films, was performed to investigate the slope of the Urbach tail. These slopes are 78 meV for films containing the lowest carbon concentration and 98 meV for those containing the highest carbon concentration.
Novel Method to Synthesize Ceria Coated Silica particles
Authors: Oh Myoung-hwan , Lee Jae Seok , Gupta Sushant , Kim Tae Kon , Kaanna Aniroddh , Singh Rajiv K
Published: July 2009

Monodispersed ceria coated silica particles were prepared by a new type of ceria precursor. The ceria precursor was synthesized by alkoxide method, which employs ethanol as solvent. The synthesized particles were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It was found that well-crystalline ceria coatings were deposited on the surface of the silica particles without post-heat treatment. In addition, the coated particles prepared by a new precursor were uniformly dispersed without the formation of hard aggregate as compared to those obtained by conventional method.
Effects of Ga Compositional Grading on CIGS Electronic Properties Relevant to Solar Cell Performance
Authors: Lee JinWoo , van Duren Jeroen K.J. , Pudov Alex , Contreras Miguel , Cohen David J.
Published: July 2009

Transient photocurrent (TPI) and photocapacitance (TPC) spectroscopy have been applied to a set of compositional graded CuIn1-xGaxSe2 (CIGS) solar cell devices deposited by the vacuum co-evaporation method at the National Renewable Energy Laboratory. These measurements provide a spectral map of the optically induced release of carriers for photon energies from below 1 eV to 2 eV. By comparing the two types of spectra one can distinguish majority from minority carrier processes and they clearly reveal a higher degree of minority carrier collection for devices in which the Ga fraction increased monotonically with distance from the junction. This agrees with notions of how compositional grading improves overall cell performance. Minority carrier collection was even more strongly enhanced in sample devices incorporating v-shaped Ga-grading. Spatial profiles of the free hole carrier densities and deep acceptor concentrations were examined using drive-level capacitance profiling (DLCP). In the compositionally graded sample devices we found that the free carrier density decreased and that defect density increased with increasing Ga fraction toward back contact.
Current Transport in Cu(In,Ga)S2 Based Solar Cells with High Open Circuit Voltage - Bulk vs. Interface
Authors: Merdes Saoussen , Johnson Benjamin , Sáez-Araoz Rodrigo , Ennaoui Ahmed , Klaer Joachim , Lauermann Iver , Mainz R. , Meeder Alexander , Klenk Reiner
Published: July 2009

Cu(In,Ga)S2 thin films prepared by rapid thermal sulfurization of metallic precursors yielded solar cells with efficiencies reaching 12.9% [1]. A good short circuit current density was observed together with open circuit voltages up to 850 mV. However, the fill factor was close to, but typically did not exceed 70%. In this contribution we report on the role of junction formation by chemical bath deposition on these parameters. Concentrations in the bath and deposition times were varied. A comparison is made between CdS and Zn(S,O) buffer layers. The influence of the incorporated gallium on surface properties was investigated by ultraviolet photoelectron spectroscopy (UPS) for the valence band edge and near edge X-ray absorption fine structure (NEXAFS) for the conduction band edge. Even in our best cell (13.1%) the activation energy of the saturation current is found to be still smaller than the band gap. High diode ideality factors and voltage dependent current collection prevent higher fill factors.
Hydrogen Diffusion in Zinc Oxide Thin Films
Authors: Beyer Wolfhard , Breuer Uwe , Hamelmann Frank , Hüpkes Jürgen , Stärk Andrea , Stiebig Helmut , Zastrow Uwe
Published: July 2009

Hydrogen diffusion in zinc oxide thin films was studied by secondary ion mass spectrometry (SIMS) measurements, investigating the spreading of implanted deuterium profiles by annealing. By effusion measurements of implanted rare gases He and Ne the microstructure of the material was characterized. While for material prepared by low pressure chemical vapour deposition an interconnected void structure and a predominant diffusion of molecular hydrogen was found, sputter-deposited ZnO films showed a more compact structure and long range diffusion of atomic hydrogen. Hydrogen diffusion energies of 1.8 – 2 eV, i.e. higher than reported in literature were found. The results are discussed in terms of a H diffusion model analogous to the model applied for hydrogen diffusion in hydrogenated amorphous and microcrystalline silicon.
Hydrogen-related defects in bulk ZnO
Authors: McCluskey Matthew D , Jokela Slade J. , Tarun Marianne C.
Published: July 2009

Zinc oxide (ZnO) has attracted resurgent interest as an active material for energy-efficient lighting applications. An optically transparent crystal, ZnO emits light in the blue-to-UV region of the spectrum. The efficiency of the emission is higher than more “conventional” materials such as GaN, making ZnO a strong candidate for solid-state white lighting. Despite its advantages, however, ZnO suffers from a major drawback: as grown, it contains a relatively high level of donors. These unwanted defects compensate acceptors or donate free electrons to the conduction band, thereby keeping the Fermi level in the upper half of the band gap. This paper reviews recent work on hydrogen donors and nitrogen-hydrogen complexes in ZnO.
Improving the High-Temperature Tensile Strength of SiTiC/TiAl Micro Composites by Interface Engineering
Authors: Suzuki Takakazu
Published: July 2009

SiC-fiber-reinforced TiAl composites (SiC/TiAl) have attractive attention due to their potential for replacing titanium and nickel-base alloys in aerospace systems such as advanced turbine engines and hypersonic vehicles where specific strength and stiffness at high temperature are critical. The interface layers of SiC/TiAl are believed to contribute strongly to its mechanical properties. A variety of interface modification, such as C, BN, W, and/or Mo coatings has been applied to the fiber to produce composites, together with the identification of several new interface modification systems, showing promise for high-performance fibers and improved composite properties. A research from a perfect cross-sectional view to get more direct and reliable interfacial information especially about bonding around the fiber circumference, has been limited partly due to the difficulty of preparing suitably thin TEM specimen without damaging the interface layers. We report our preparation method for a perfect cross-sectional TEM specimen of SiC/TiAl and the interface characterization results.

Single SiC-based Si-Ti-C-O fiber (SiTiC) ˜13 μm in diameter containing about 2% Ti to improve its thermal stability has been used as a reinforcement. Chemical or physical vapor deposition has been used to deposit C or TiAl layer. C layer has been deposited-uniformly around the fiber at a thickness of about 100 nm and TiAl coating at about 1400 nm. C layer consisted of large amounts of micro crystals of about 1-30 nm accumulated around the interface of C layer and fiber. TiAl layer consisted of crystals of about 60-360nm.

The specimen has been annealed at 1173 K for 2 hrs in Ar, and prepared by sandwiching and 3mm disks obtained by ultrasonic drilling and mechanical-polishing to ∼100 μm. Those disks have been further ground by a dimpler to ∼10 μm, and argon-ion-milling to get an electron-beam-transparent foil. H-9000UHR II TEM operating at 300 kV, equipped with EDX (prove 1nm) has been used.

Interfacial reaction and diffusion mainly occurred in the interface between the C layer and SiTiC fiber and the C and TiAl layers. No direct reaction or diffusion occurred between the SiTiC fiber and TiAl layer. Small amounts of needle-like compound assigned as Aluminum Titanium Carbide, (Ti3AlC)5C, propagating into the fiber has been found at the interface area. These compounds consist of C, Si, O, Ti, and Al, indicating they are reaction and diffusion products of SiTiC fiber and TiAl. Such Aluminum Titanium Carbide propagating into the fiber seems to induce new stress concentration and generate new crack in the fiber and degrade the fiber and the composite strength. Combined with the tensile testing of SiTiC/TiAl single fiber reinforced composites reported previously, we surmise that the large amounts of small crystals accumulating in the C layer contribute to resistance to interfacial reaction and diffusion between the fiber and TiAl layer.
In Vitro Human Osteoblast Responses to Titanium Oxide-Based Surfaces with Varying Topology and Composition
Authors: Collier Charles Andrew , Paillard Julien M. , Markaki Athina E. , Curran James A. , Griffiths Helen J , Clyne T William
Published: July 2009

The surface topology and composition of prosthetic implant materials affect cell responses and are therefore important design features. Plasma electrolytic oxidation (PEO) is a surface modification technique that can be used to produce oxidized surfaces with various surface properties. In this work, Ti-6Al-4V was PEO processed to give two surfaces with different morphologies but similar chemical composition. Surface characteristics were assessed using X ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, stylus profilometry and contact angle measurement.

In vitro culture of human foetal osteoblasts (HOB) was performed on the surfaces, to examine cell responses to them. Cellular proliferation, morphology and differentiation were examined, using the AlamarBlue assay, SEM imaging and an alkaline phosphatase (ALP) activity assay respectively. Additionally, the individual effects of oxides present in the PEO processed surfaces (rutile and anatase) on the cells were examined, by binding them in powder form to produce surfaces with similar morphology, but different composition.

Changes in the topology and chemistry of the surfaces affected osteoblast response. HOB proliferated more on the rougher PEO surface, and also displayed greater ALP activity. Also, cells responded differently to surfaces containing just rutile or anatase, indicating that the chemical phase of titanium oxide is of consequence for implant design.
Effect of chemical crosslinking on the free-strain recovery characteristics of amorphous shape-memory polymers
Authors: Ortega Alicia M. , Yakacki Christopher Michael , Dixon Sean A. , Greenberg Alan R. , Gall Ken
Published: July 2009

The goal of this study is to investigate the fundamental relationship between the extent of crosslinking and shape-memory behavior of amorphous, (meth)acrylate-based polymer networks. The polymer networks were produced by copolymerization of tert-butyl acrylate (tBA) and poly(ethylene glycol) dimethacrylates of differing molecular weights (PEGDMA). Polymer compositions were tailored via the amount (weight percent (wt%)) and molecular weight of the PEGDMA crosslinking agents added to produce four materials with varying levels of crosslinking (0, 2, 10, and 40 wt% crosslinking agent corresponding to 0, 0.6, 3.2, and 16.6 mole%) and nearly equal glass transition temperatures (Tg). The effect of crosslinking on deformation limits and free-strain recovery is evaluated. Near complete strain recovery was demonstrated by all materials; however, absolute recovery strain decreased with increasing crosslinking due to a corresponding decrease in strain-to-failure. The results provide insights regarding the link between polymer structure, deformation limits, and strain-recovery capabilities of this class of shape-memory polymers. An improved understanding of this relationship is pivotal for optimizing system response for a wide range of shape-memory applications.
Spiral Photonic Actuator
Authors: Kwang-Yong Jin , Seul-Ki Park , Ji-Hyun Jang , Koh Cheongyang , Graham Mattew J , Soo-Jin Park , Changwoon Nah , Myung-Hoon Lee , Cheng Stephen Z. D. , Thomas Edwin , Kwang-Un Jeong
Published: July 2009

There has been a significant effort to create spiral sensors by changing either the periodic d-spacing of the structure or the dielectric constants of the materials by combining the multi-faceted environmental responsiveness of polymer hydrogels with dielectrical structures.1 Reversible spiral switches with dimensional functionalities that respond to chemical environment were constructed. When the spiral photonic actuator was swollen in hydrophilic acetic acid, right-handed spiral structures are formed, while the spiral photonic actuator was swollen in hydrophobic hexane, left-handed spiral structures are formed. All actuators returned back to the transparent planar state after deswelling processes. These reversible spiral photonic actuators can be applied in the application of mechanical actuators, electrical devices, and optical components.
Sensing Materials for the Detection of Chlorine Gas in Embedded Piezoresistive Microcantilever Sensors
Authors: Porter Timothy L. , Vail Tim , Wooley Amanda , Venedam Richard
Published: July 2009

Embedded piezoresistive microcantilever (EPM) sensors provide a small, simple and robust platform for the detection of many different types of analytes. These inexpensive sensors may be deployed in battery-powered handheld units, or interfaced to small, battery-powered radio transmitter-receivers (motes), for deployment in mesh networks of many sensors. Previously, we have demonstrated the use of EPM sensors in the detection of hydrogen fluoride gas, organophosphate nerve agents, volatile organic compounds (VOC’s), chlorinated hydrocarbons in water, and others. Here, we report on the design of EPM sensors functionalized for the detection of chlorine gas, or Cl2. We have constructed EPM sensors using composite materials consisting of a polymer or hydrogel matrix loaded with agents specific for the detection of Cl2 such as NaI. These materials were tested in both controlled laboratory conditions and in outdoor releases. Stability of the sensing materials under conditions of high temperature were also studied. Results are presented for gas exposures ranging from 1000 ppm to 20 ppm.
The β104–109 sequence is essential for the secretion of correctly folded single-chain βα horse LH/CG and for its FSH activity
Authors: Galet Colette , Guillou Florian , Foulon-Gauze Florence , Combarnous Yves , Chopineau Maryse
Published: July 2009

The dual LH and FSH activity of the equine LH (eLH)/equine chorionic gonadotropin (eCG) in heterologous species makes eLH/CG a good model to study structure/function relationships of gonadotropins. In order to bypass the problem of intracellular association of the heterodimer, a recombinant single-chain βαeLH/CG was used to identify sequences in the β-subunit involved in the secretion and activities of the hormone. The C-terminal region of the β-subunit was progressively truncated. All resulting truncated single-chains were secreted in the media as detected by an anti-βpeptide antibody in reducing conditions. However, using a conformation sensitive ELISA we show that the truncated single-chains were differently recognized: deletion of the last 40 amino acids of the β-subunit (β109αeLH/CG) resulted in a 90% decrease in the recognized correctly folded hormone compared with the full-length βαeLH/CG single-chain and no properly folded hormone was detected in the secretion medium when the last 46 amino acids of the β-subunit were deleted (β103αeLH/CG). We thus focused on the six amino acids sequence 104–109, which belongs to the seat-belt region. Mutation of the 104–109 sequence in alanines in the full-length βαeLH/CG (β104–109Alaα) led to a 50% decrease in the production of properly folded hormone in COS-7 as well as in αT3 pituitary cells. Moreover, the FSH activity of this mutant was decreased by 70% whereas its LH activity remained intact. These data lead us to conclude that the 104–109 region of the β eLH/CG subunit is essential for the secretion of a fully folded βαeLH/CG and for its FSH activity but not for its LH activity.
Hydraulic Properties of Variously Weathered Granitic Bedrock in Headwater Catchments
Authors: Katsura Shin'ya , Kosugi Ken'ichirou , Mizutani Tasuku , Mizuyama Takahisa
Published: July 2009

Recent studies have emphasized the importance of bedrock in hydrologic processes occurring in headwater catchments. To understand water flow processes through variously weathered bedrock, we measured the saturated hydraulic conductivity, Ks, and water retention characteristics of weakly to highly weathered Tanakami granite and Rokko granite core samples. On the basis of these core‐scale properties, along with the core shape and in situ Ks measurements, we defined two groups of bedrock: CM class (weakly weathered) and CL to DL class (moderately to highly weathered). The CM class bedrock cores had almost no effective porosity (i.e., the amount of porosity that effectively contributes to water flow) and therefore extremely small core‐scale Ks, indicating that the matrix could be regarded as essentially impermeable. The in situ Ks was much larger than the core‐scale values, however, and the core shape showed apparent fractures, suggesting that water did flow preferentially through the fractures. The volumetric water content of the CL– to DL–class bedrock water retention curves changed little in the dry range but changed gradually in the wet range, resulting in a moderate core‐scale Ks of 10−5 to 10−3 cm s−1 The core‐scale Ks values were well explained by the parameters characterizing the water retention curve. The similarity of the in situ Ks to the core‐scale values, and the lack of fractures in the core shape, suggested that water flow could be characterized as matrix flow. The hydraulic properties of weathered granite at other sites followed the trends observed at our sites, implying wide applicability of the findings in this study to various types of weathered granite.
Is there still a problem with lead in drinking water in the European Union?
Authors: Hayes C. R. , Skubala N. D.
Published: July 2009

The presence of lead in drinking water poses a range of risks to human health, including the retardation of some aspects of child development, the inducement of abortion, and other clinical disorders. The extent of these risks has not been quantified at the European Union (EU) scale. A number of sampling methods are in use across the EU, some of which are inadequate for determining the concentrations of lead in drinking water at consumers' taps. In consequence, non-compliance with the EU standards for lead in drinking water has been under-estimated. Emerging data indicates significant non-compliance with these standards in some countries, particularly with the 10 μg l−1 standard that will become a legal requirement in 2013; the current interim standard of 25 μg l−1 is also exceeded in some locations. An initial estimate is that 25% of domestic dwellings in the EU have a lead pipe, either as a connection to the water main, or as part of the internal plumbing, or both, potentially putting 120 million people at risk from lead in drinking water within the EU. These issues are relevant to the implementation of the Protocol on Water and Health and to drinking water safety planning.
Enteric illness risks before and after water treatment improvements
Authors: Frost Floyd J. , Tollestrup Kristine , Roberts Melissa , Kunde Twila R. , Craun Gunther F. , Harter Lucy
Published: July 2009

This study evaluated whether occurrence of acute gastrointestinal illnesses declined after filtration and ozonation were added to a previously unfiltered, chlorinated high-quality surface water source in a northwest United States city. Enteric and other illnesses were recorded for two 6-month periods for control and intervention sites in the same city. During phase 1, chlorinated, unfiltered drinking water for both sites was obtained from protected watersheds. During phase 2, the intervention site received chlorinated, filtered and ozonated drinking water. The water was not altered in the control site. No overall differences were found in the risk of any of the illnesses after the new water treatment plant was completed. There was a significantly increased risk of diarrhoea and highly credible gastrointestinal illness in participants with three or more episodes of the same type of illness during phase 1.
Decline in recycled water quality during short-term storage in open ponds
Authors: Higgins Jennifer , Warnken Jan , Teasdale Peter R. , Arthur J. Michael
Published: July 2009

Changes were assessed in urban wastewater treatment plant (WWTP) effluent quality during short-term storage in open surface ponds. Water quality was monitored over five years at the inlets and outlets of open storage ponds located at three biological nutrient removal plants. Pond influent temperature, rainfall and sewage inflow were not found to be major factors. However, there was a trend for water temperature to be correlated negatively with nitrogenous nutrient and positively with faecal coliform values. The observed increases in faecal coliforms, nutrients and chemical oxygen demand were most likely caused through avian faecal contamination. These increases challenge the notion that pond storage has a positive or negligible effect on effluent quality. The observed one to two orders of magnitude increase in faecal coliforms may affect reuse scheme viability by limiting the range of uses under Australian water recycling guidelines. Potential improvements to short-term recycled water storage management at WWTPs could include the integration of monitoring requirements in WWTP discharge licences and recycling guidelines and the monitoring of all water quality parameters, including microbiological ones, at the point of entry into the recycled water distribution system, after WWTP storage, rather than directly post-disinfection.
Income and Health in Canada: Canadian Researchers' Conceptualizations Make Policy Change Unlikely
Authors: Macdonald Jennifer , Raphael Dennis , Labonte Ronald , Colman Ronald , Torgerson Renée , Hayward Karen
Published: July 2009

The research reported here identified and evaluated gaps in Canadian knowledge and research activity concerning the role of income and its distribution in influencing health outcomes. The study consisted of an analysis of 241 recent Canadian research studies, the components of which were compared with 40 U.K. and 40 Finnish studies that applied advanced conceptualizations of the income-health relationship. Canadian health researchers rarely made explicit their conceptualizations of how income was approached in their studies, and most did not identify the structural mechanisms that mediate the income-health relationship. There were few Canadian longitudinal studies capable of illuminating the role of income in health across the lifespan. Many Canadian studies identified pathways by which income might influence health, but these conceptualizations were underdeveloped. Canadian researchers need to strengthen their conceptualizations of how income and its distribution affect health. While empirical research is only one contributor to positive policy change, the narrow nature of Canadian work will do little to influence this process. Interdisciplinary work on the political, economic, and social forces that contribute to income inequalities has the potential, when combined with political and social action, to facilitate public policy in support of health.
Prospects for a Genuine Revival of Primary Health Care—Through the Visible Hand of Social Justice Rather than the Invisible Hand of the Market: Part I
Authors: Katz Alison Rosamund
Published: July 2009

In a two-part article (the first part in this Journal issue), the author explores the prospects for a genuine revival of the social justice project of “Health for All by the Year 2000,” launched by the WHO and UNICEF in 1978 at Alma-Ata in the former Soviet Union, with reference (in Part I) to the World Health Report 2008, Primary Health Care: Now More than Ever, and the report of the WHO Commission on Social Determinants of Health, also published in 2008; and (in Part II) to Global Health Watch 2: An Alternative World Health Report and the perspectives of anti-capitalist, real socialist, environmental, and people's movements for economic and social justice. The reports are reviewed in terms of the original values and principles of Alma-Ata (social justice and human rights) and the structural foundations of the primary health care (PHC) project (a new international economic order and emancipatory development of decolonized countries). A genuine revival of the PHC project and of Health for All, which is its implicit objective, will not be possible unless the multiple crises that we are confronting today—in energy, water, food, finance, the environment, science, information, and democracy—are recognized as capitalist crises and addressed in these terms. In short, the invisible hand of the market must be replaced by the visible hand of social justice.
Influence of Preconditioning and Blocking on Accuracy in Solving Markovian Models
Authors: Bylina Beata , Bylina Jarosław
Published: July 2009

Influence of Preconditioning and Blocking on Accuracy in Solving Markovian Models

The article considers the effectiveness of various methods used to solve systems of linear equations (which emerge while modeling computer networks and systems with Markov chains) and the practical influence of the methods applied on accuracy. The paper considers some hybrids of both direct and iterative methods. Two varieties of the Gauss elimination will be considered as an example of direct methods: the LU factorization method and the WZ factorization method. The Gauss-Seidel iterative method will be discussed. The paper also shows preconditioning (with the use of incomplete Gauss elimination) and dividing the matrix into blocks where blocks are solved applying direct methods. The motivation for such hybrids is a very high condition number (which is bad) for coefficient matrices occuring in Markov chains and, thus, slow convergence of traditional iterative methods. Also, the blocking, preconditioning and merging of both are analysed. The paper presents the impact of linked methods on both the time and accuracy of finding vector probability. The results of an experiment are given for two groups of matrices: those derived from some very abstract Markovian models, and those from a general 2D Markov chain.
Design of the State Predictive Model Following Control System with Time-Delay
Authors: Wang Dazhong , Wu Shujing , Okubo Shigenori
Published: July 2009

Design of the State Predictive Model Following Control System with Time-Delay

Time-delay systems exist in many engineering fields such as transportation systems, communication systems, process engineering and, more recently, networked control systems. It usually results in unsatisfactory performance and is frequently a source of instability, so the control of time-delay systems is practically important. In this paper, a design of the state predictive model following control system (PMFCS) with time-delay is discussed. The bounded property of the internal states for the control is given, and the utility of this control design is guaranteed. Finally, examples are given to illustrate the effectiveness of the proposed method, and state predictive control techniques are applied to congestion control synthesis problems for a TCP/AQM network.