bluuebunny/crossref_metadata_2025 huggingface dataset:
Sol–gel derived metal oxides doped with silver nanoparticles as tunable plasmonic materials
Authors: Dolgov Leonid , Kiisk Valter , Reedo Valter , Maaroos Aarne , Sildos Ilmo , Kikas Jaak
Published: April 2010

New composite materials made of transition metal oxides doped with silver nanoparticles are proposed. Titanium and zirconium dioxide matrices were prepared by sol–gel method adjusted for addition of silver nanodopants. Commercially available silver nanoparticles in the form of powder (30–50 nm) or colloidal solution (5–15 nm) were used for doping of oxide hosts. To recover plasmonic properties of silver after annealing in air, reduction of samples in the H2:Ar atmosphere was performed. As a result, the silver‐containing TiO2 and ZrO2 films of good optical quality with plasmonic absorption near 400 nm were obtained. The potential of embedding of luminescent markers (like rare earth ions) into considered films is discussed.
Lean neodymium Nd–Fe–B magnets containing minor addition of titanium
Authors: Spyra Marzena , Derewnicka Daniela , Leonowicz Marcin
Published: April 2010

The effect of titanium addition on the structure and magnetic properties was studied for the nanocomposite Nd7Fe79–xB14Tix and Nd8Fe78–xB14Tix systems. The alloys were rapidly solidified by melt‐spinning with the roll speed 20 m/s. The overquenched, amorphous ribbons were subsequently crystallization annealed for 20 min at 953–973 K. It was found that the addition of 2 and 4 at% of Ti leads to a substantial increase of the coercivity and maximum energy product of the nanocomposite magnets while maintaining the remanence unchanged. The highest properties were obtained for the alloys containing 4 at% of Ti. The maximum energy product of 143 kJ/m3 was achieved for the Nd8Fe74B14Ti4 alloy. The TEM studies showed substantial differences in the morphology of the alloys. The ternary alloys contain grains of various sizes of approximately 300 nm. The alloys containing 4 at% of Ti exhibit more homogeneous structure with the crystal sizes up to 30 and 50 nm for the Nd8Fe74B14Ti4 and Nd7Fe75B14Ti4 alloys, respectively. More detailed information on the phase constitution was obtained from the Mössbauer spectroscopy. Comparison of the Ti‐free and 4 at% Ti alloys revealed that the amount of the hard magnetic Nd2Fe14B phase decreases from 84.53 to 69.88% for the Nd7Fe79–xB14Tix system and increased from 66.60 to 82.48% for Nd8Fe78–xB14Tix system.
Corrosion resistance of nickel‐free austenitic stainless steels/hydroxyapatite composites
Authors: Tulinski Maciej , Jurczyk Mieczyslaw
Published: April 2010

In a newly introduced manufacturing process of nickel‐free austenitic stainless steels with nitrogen absorption treatment (M. Sumita et al., Mater. Sci. Eng. C 24, 753 (2004) [1]), small devices can be precisely machined in a ferritic phase and than during nitrogenization of their surfaces in nitrogen gas at temperature approx. 1200 °C they become nickel‐free austenitic stainles steels with better mechanical and corrosion resistance properties. Using the combination of mechanical alloying (MA), heat treatment and nitrogenation of elemental microcrystalline Fe, Cr, Mn and Mo powders it is possible to synthesize a nanocrystalline nickel‐free stainless steels. Nanocomposites with addition of hydroxyapatite (HA) have been prepared for the best samples. Phase transformation from ferritic to austenitic was confirmed by XRD analysis. Also the microhardness of the final bulk material was studied using Vickers method. The result is almost two times greater than in austenitic steel obtained by conventional methods. This effect is directly connected with structure refinement and nitriding. Mechanical alloying and nitriding are very effective technologies to improve also the corrosion resistance of stainless steel. Decreasing the corrosion current density is a distinct advantage for prevention of ion release and it leads to better cytocompatibility. According to existing conceptions, decreasing of material's crystallites size to nanometric scale allows to achieve much better mechanical properties (e.g. microhardness) compared to conventional materials (A.S. Edelstain et al., Prog. Mater. Sci. 42, 5 (1997) [2]). The results show that from mechanical and corrosion properties point of view nanocrystalline nickel‐free stainless steels and nickel‐free stainless steel/hydroxyapatite nanocomposites could be promising bionanomaterials for use as a hard tissue replacement implants, e.g. orthopedic implants. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of palladium addition on the electrochemical properties of amorphous 2Mg + 3d alloys doped by nickel atoms (3d = Fe, Ni)
Authors: Jarzebski Maciej , Okonska Izabela , Jurczyk Mieczyslaw
Published: April 2010

Amorphous 2Mg+ 3d/x wt% Ni materials were prepared by mechanical alloying (MA) of Mg and 3d elemental powders (3d = Fe, Ni x =0, 100 and 200 wt.%) under high purity argon atmosphere in SPEX 8000 Mixer Mill. The effect of the Ni addition on the electrochemical properties of the synthesized nanostructured alloys was investigated in details. The discharge capacity of amorphous 2Mg+Fe (Ni) high energy ball milled with Ni was improved. With increasing nickel content in the studied 2Mg+Fe (Ni) materials, at first cycle, the discharge capacity increases first and then decreases, and for example, for x = 100 in 2Mg+Fe reaches a maximum value of 155 mAh g–1. Additionally, when coated with palladium, the discharge capacity of an amorphous 2Mg+Fe (Ni) powders was increased as well. The catalytic elements (Ni, Pd) were distributed on the surface of ball milled alloy particles homogenously and role of these particles is to catalyze the dissociation of molecular hydrogen on the surface of studied alloy. Mechanical coating with palladium effectively reduced the degradation rate of the studied electrode materials. Compared to that of the uncoated powders, the degradation of the coated was suppressed. The amorphous Mg‐based hydrides offer a breakthrough in prospects for practical applications (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
XRD study of the transformation characteristics of severely plastic deformed Ni‐Ti SMAs
Authors: Braz Fernandes Francisco M. , Mahesh Karimbi K. , Silva Rui J. C. , Gurau Carmela , Gurau Gheorghe
Published: April 2010

Severe plastic deformation (SPD) of Ni‐Ti alloys (Ti‐rich and Ni‐rich) has been performed by High Pressure Torsion (HPT). Aim of the study was to follow the structural evolution in the samples subjected to SPD, in the martensite ↔ austenite phase transformation temperature region. HPT is carried out at room temperature (RT) on two separate Ni‐Ti alloy samples, Ti‐rich alloy with martensite finish temperature (Mf) above and Ni‐rich with austenite finish temperature (Af) below RT. The samples have been studied by in situ X‐ray diffraction (XRD) in order to get information about (i) the transformation characteristics and (ii) the structural evolution after annealing. The results showed that the Ti‐rich alloy retained one step phase transformation (Martensite ↔ Austenite) after HPT, as well as HPT followed by heat treatment. In the HPT condition, Ni‐rich alloy were found to undergo one step phase transformation (Martensite ↔ Austenite), whereas, heat treatment after HPT resulted in the presence of intermediate R‐phase transformation both while heating and cooling in the diffraction chamber. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
FeCoBSiNb bulk metallic glasses with Cu additions
Authors: Stoica Mihai , Roth Stefan , Eckert Jürgen , Karan Trisha , Ram Shanker , Vaughan Gavin , Yavari Alain Reza
Published: April 2010

The effect of Cu additions (1, 2 and 3 at.%) on the glass forming ability (GFA) and magnetic properties of [(Fe0.5Co0.5)0.75Si0.05B0.20]96Nb4 is studied. As the Cu content increases, the GFA deteriorates. The structure of the samples, as well as the crystallization behavior was in‐situ studied by means of synchrotron beam. The as‐cast 1 mm diameter rods are characterized by a mixture of (nano)‐crystals and amorphous matrix. Upon heating, the pre‐existing nuclei grow, without forming new crystalline phases. The magnetic properties are characteristic for soft magnetic materials. Despite that several crystalline magnetic phases can be identified in the as‐cast samples, only one single magnetic transition prior to complete crystallization could be identified upon heating. The values for saturation magnetization and for Curie temperature are relatively close for all samples. The initial permeability of the Cu containing samples seems to be higher than that for the fully amorphous [(Fe0.5Co0.5)0.75Si0.05B0.20]96Nb4 alloy (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ab‐initio modeling of a‐Si and a‐Si:H
Authors: Ribeiro Ricardo M. , Torres Vítor J B. , Vasilevskiy Mikhail I. , Barros André , Briddon Patrick R.
Published: April 2010

The simulation of a‐Si is complicated because there is no direct experimental data, as there are for crystals. Our approach to simulate a‐Si is to build several relatively small amorphous samples and, later, the properties we wish to calculate are averaged over all samples. We applied the Wooten, Winer and Weaire bond switch to 64 atom cubic supercell of crystalline silicon. This mechanism was used to create 15 samples of continuous random network of silicon. For each supercell, the volume and atomic relaxation were allowed in order to minimize the total energy, using a density functional‐pseudopotential code. The radial and angular distributions, the electronic and vibrational density of states, and the Raman spectra were calculated. The radial distribution agrees very well with experimental data. The angular distribution has its maximum at 109.4 degree. The experimental positions and relative intensities of the Transverse Optical (TO) and Transverse Acoustic vibrational modes are well reproduced, with 14 and 25 cm‐1 peak deviations, respectively. The shape of the calculated Raman spectra agrees well with experimental data, being the intense TO peak shifted by 50 cm‐1. The TO width at half‐weight is very well reproduced. Introducing hydrogen in the a‐Si samples, decorating all the undercoordinated Si atoms and at bond centres of floating bonds, the hydrogen vibrational frequencies of the relaxed structures agree very well with experimental data. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural elucidation ofN‐oxidized clemastine metabolites by liquid chromatography/tandem mass spectrometry and the use ofCunninghamella elegansto facilitate drug metabolite identification
Authors: Åberg Annica Tevell , Löfgren Helena , Bondesson Ulf , Hedeland Mikael
Published: April 2010

Cunninghamella elegansis a filamentous fungus that has been shown to biotransform drugs into the same metabolites as mammals. In this paper we describe the use ofC. elegansto aid the identification of clemastine metabolites since high concentrations of the metabolites were produced and MSnexperiments were facilitated. The combination of liquid chromatography and tandem mass spectrometry with two different ionization techniques and hydrogen/deuterium exchange were used for structural elucidation of the clemastine metabolites. Norclemastine, four isomers of hydroxylated clemastine, and twoN‐oxide metabolites were described for the first time inC. elegansincubations. TheN‐oxidations were confirmed by hydrogen/deuterium exchange and deoxygenation (−16 Da) upon atmospheric pressure chemical ionization mass spectrometry. By MSnfragmentation it was concluded that two of the hydroxylated metabolites were oxidized on the methylpyrridyl moiety, one on the aromatic ring with the chloro substituent, and one on the aromatic ring without the chlorine. Copyright © 2010 John Wiley & Sons, Ltd.
Behaviour of tetraalkylammonium ions in high‐field asymmetric waveform ion mobility spectrometry
Authors: Aksenov Alexander A. , Kapron James T.
Published: April 2010

High‐field asymmetric waveform ion mobility spectrometry (FAIMS) is an ion‐filtering technique recently adapted for use with liquid chromatography/mass spectrometry (LC/MS) to remove interferences during analysis of complex matrices. This is the first systematic study of a series of singly charged tetraalkylammonium ions by FAIMS‐MS. The compensation voltage (CV) is the DC offset of the waveform which permits the ion to emerge from FAIMS and it was determined for each member of the series under various conditions. The electrospray ionization conditions explored included spray voltage, vaporizer temperature, and sheath and auxiliary gas pressure. The FAIMS conditions explored included carrier gas flow rate, electrode temperature and composition of the carrier gas. Optimum desolvation was achieved using sufficient carrier gas (flow rate ≥2 L/min) to ensure stable response. Low‐mass ions (m/z 100–200) are more susceptible to changes in electrode temperature and gas composition than high mass ions (m/z 200–700). As a result of this study, ions are reliably analyzed using standard FAIMS conditions (dispersion voltage −5000 V, carrier gas flow rate 3 L/min, 50% helium/50%nitrogen, inner electrode temperature 70°C and outer electrode temperature 90°C). Variation of FAIMS conditions may be of great use for the separation of very low mass tetraalkylammonium (TAA) ions from other TAA ions. The FAIMS conditions do not appear to have a major effect on higher mass ions. Copyright © 2010 John Wiley & Sons, Ltd.
Sequential Fe3O4/TiO2 enrichment for phosphopeptide analysis by liquid chromatography/tandem mass spectrometry
Authors: Choi Sunkyu , Kim Jaeyoon , Cho Kun , Park Gunwook , Yoon Jong Hyuk , Park Sehoon , Yoo Jong Shin , Ryu Sung Ho , Kim Young Hwan , Kim Jeongkwon
Published: April 2010

Protein phosphorylation regulates a wide range of cellular functions and is associated with signaling pathways in cells. Various strategies for enrichment of phosphoproteins or phosphopeptides have been developed. Here, we developed a novel sequential phosphopeptide enrichment method, using magnetic iron oxide (Fe3O4) and titanium dioxide (TiO2) particles, to detect mono‐ and multi‐phosphorylated peptides. In the first step, phosphopeptides were captured on Fe3O4 particles. In a subsequent step, any residual phosphopeptides were captured on TiO2 particles. The particles were eluted and rinsed to yield phosphopeptide‐enriched fractions that were combined and analyzed using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The validity of this sequential Fe3O4/TiO2 enrichment strategy was demonstrated by the successful enrichment of bovine α‐casein phosphopeptides. We then applied the sequential Fe3O4/TiO2 enrichment method to the analysis of phosphopeptides in L6 muscle cell lysates and successfully identified mono‐ and multi‐phosphorylated peptides. Copyright © 2010 John Wiley & Sons, Ltd.
Accelerator mass spectrometry offers new opportunities for microdosing of peptide and protein pharmaceuticals
Authors: Salehpour Mehran , Ekblom Jonas , Sabetsky Vladimir , Håkansson Karl , Possnert Göran
Published: April 2010

Accelerator Mass Spectrometry (AMS) is an ultra‐sensitive analytical method which has been instrumental in developing microdosing as a strategic tool in early drug development. Considerable data is available for AMS microdosing using typical pharmaceutical drugs with a molecular weight of a few hundred Daltons. The so‐called biopharmaceuticals such as proteins offer interesting possibilities as drug candidates; however, experimental data for protein microdosing and AMS is scarce. The analysis of proteins in conjunction with early drug development and microdosing is overviewed and three case studies are presented on the topic. In the first case study AMS experimental data is presented, for the measured concentration of orally administered recombinant insulin in the blood stream of laboratory rabbits. Case study 2 concerns minimum sample size requirements. AMS samples normally require about 1 mg of carbon (10 µL of blood) which makes AMS analysis unsuitable in some applications due to the limited availability of samples such as human biopsies or DNA from specific cells. Experimental results are presented where the sample size requirements have been reduced by about two orders of magnitude. The third case study concerns low concentration studies. It is generally accepted that protein pharmaceuticals may be potentially more hazardous than smaller molecules because of immunological reactions. Therefore, future first‐in‐man microdosing studies might require even lower exposure concentrations than is feasible today, in order to increase the safety margin. This issue is discussed based on the current available analytical capabilities. Copyright © 2010 John Wiley & Sons, Ltd.
The early days of ECASIA
Authors: Werner H. W.
Published: April 2010

The reasons for the foundation of ECASIA lay far back in the late 50s and 60s of the last century, when material analysis was identical with bulk analysis. With the appearance of surface analytical techniques such as SIMS and AES, the importance of surface analysis became evident. Unfortunately, analysis at that time was considered as inferior to fundamental studies. The infrastructure of analytical laboratories, worldwide, was poor, compared with today's abundant facilities. To cope with all these difficulties, cooperation of all those involved in the application of surface techniques to practical problems was considered inevitable. This resulted in the establishment of the concept of ECASIA in 1982 followed by the first ECASIA conference in 1985. Copyright © 2010 John Wiley & Sons, Ltd.
ToF‐SIMS investigation of ancient ceramics from the Quartaia Site, Tuscany (Italy)
Authors: Tognazzi Antonio , Dattilo Arduino Massimo , Bracchini Luca , Aggravi Marianna , Benetti Francesca , Mugnaini Edoardo , Magnani Agnese , Rossi Claudio
Published: April 2010

The study of ancient ceramic fragments provides important information about the production technology that characterized a certain civilization. In this work, time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS), atomic absorption spectroscopy(AAS) and scanning electron microscopy (SEM) were used to study two types of ceramics having different impasto (depurata and non‐depurata ceramics). Ancient fragments, belonging to the archeological site of Quartaia (Tuscany, Italy), were examined to obtain chemical and spatial information on inorganic and organic components. The results revealed the presence of the major elements, i.e. Al, Mg, Na, K, Ca, Si, Fe; minor elements, i.e. Cr, Cu, Mn, Pb; and organic components adsorbed during the firing process, both in depurata and non‐depurata ceramics. In addition, through ToF‐SIMS imaging, it was possible to highlight inorganic components, i.e. Na, Ca, Fe, K and Mg, that showed an inhomogeneous spatial distribution in non‐depurata ceramics. These chemical elements appear to be concentrated inside the inclusions of the non‐depurata ceramics impasto. These unique results demonstrated that ToF‐SIMS is a potential tool to reveal important aspects of the Quartaia ceramic production technology and it results in a very promising technique for the archeological studies. Copyright © 2010 John Wiley & Sons, Ltd.
Bacterial Nanofluidic Structures for Medicine and Engineering
Authors: Hesse William R. , Freedman Kevin J. , Yi Dong Kee , Ahn Chi Won , Kim MinJun
Published: April 2010

Bacteria are microscopic, single‐celled organisms that utilize a variety of nanofluidic structures. One of the best known and widely used nanofluidic structures that are derived from bacteria is the α‐hemolysin pore. This pore, which self‐assembles in lipid bilayers, has been used for a wide variety of sensing applications, most notably, DNA sensing. Synthetic pores drilled in a wide variety of materials, such as silicon nitride and polymers have been developed that use inspiration from the α‐hemolysin pore. Higher‐aspect‐ratio nanofluidic structures, akin to nanotubes, are also synthesized by bacteria. Examples of such structures include those that are associated with bacterial transport apparatus, such as pili, and are used by bacteria to facilitate the transfer of genetic material from one bacterium to another. Flagella, and its associated structures, such as the rod and hook, are also tubular nanostructures, through which the protein, flagellin, travels to assemble the flagellum. Genetic engineering allows for the creation of modified bacterial nanopores and nanotubes that can be used for a variety of medical and engineering purposes.

Frontispiece images reproduced with permission from References 55,8,85. Copyrights 1996, American Association for the Advancement of Scicnce, 2009, Elsevier, and 2007, Institute of Physics, respectively.

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Bionanosphere Lithography via Hierarchical Peptide Self‐Assembly of Aromatic Triphenylalanine
Authors: Han Tae Hee , Ok Taedong , Kim Jangbae , Shin Dong Ok , Ihee Hyotcherl , Lee Hee‐Seung , Kim Sang Ouk
Published: April 2010

A nanolithographic approach based on hierarchical peptide self‐assembly is presented. An aromatic peptide of N‐(t‐Boc)‐terminated triphenylalanine is designed from a structural motif for the β‐amyloid associated with Alzheimer's disease. This peptide adopts a turnlike conformation with three phenyl rings oriented outward, which mediate intermolecular π–π stacking interactions and eventually facilitate highly crystalline bionanosphere assembly with both thermal and chemical stability. The self‐assembled bionanospheres spontaneously pack into a hexagonal monolayer at the evaporating solvent edge, constituting evaporation‐induced hierarchical self‐assembly. Metal nanoparticle arrays or embossed Si nanoposts could be successfully created from the hexagonal bionanosphere array masks in conjunction with a conventional metal‐evaporation or etching process. Our approach represents a bionanofabrication concept that biomolecular self‐assembly is hierarchically directed to establish a straightforward nanolithography compatible with conventional device‐fabrication processes.
Value of prenatal ultrasound and magnetic resonance imaging in assessment of congenital primary cytomegalovirus infection
Authors: Lipitz S. , Hoffmann C. , Feldman B. , Tepperberg‐Dikawa M. , Schiff E. , Weisz B.
Published: April 2010

Objective

To evaluate the outcome of pregnancies with proven and well‐dated primary cytomegalovirus (CMV) infection with and without abnormal fetal ultrasound and magnetic resonance imaging (MRI) findings.

Methods

This was a prospective study of 38 singleton pregnancies with proven vertical transmission of CMV and prenatal ultrasound and MRI examinations. Entry requirements included precise dating of the pregnancy and known time of maternal infection. Neonatal follow‐up was a strict requirement, all neonates having eye fundus examination, a brain ultrasound scan and a hearing evaluation. All children were followed up by specialists in child development.

Results

Primary CMV infection occurred during the first trimester in 10 patients, the second trimester in 19 and the third trimester in nine. Twenty‐four of 29 patients with first‐ or second‐trimester infections delivered; the other five underwent termination of pregnancy (TOP). Three patients had abnormal sonographic findings with normal MRI. Of these, two had damage to the auditory system. In both cases, infection occurred during the first trimester. In 16 patients with first‐ or second‐trimester infection, both ultrasound and MRI exams were normal; there was one TOP but all other cases had favorable outcome, with normal hearing and developmental evaluations. The outcome of five pregnancies with subtle MRI findings and normal ultrasound exam was also favorable. None of the children infected during the third trimester was affected.

Conclusion

The outcome of congenital primary CMV infection with normal prenatal ultrasound and MRI exams is favorable. The prognostic value of subtle MRI findings is limited and when such findings are isolated, termination of pregnancy is unlikely to be justified. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Coverage for composite event detection in wireless sensor networks
Authors: Yang Yinying , Ambrose Arny , Cardei Mihaela
Published: April 2010

A wireless sensor network can detect single (or atomic) events or composite events. Since sensors are battery powered and in general, it is hard to recharge them, energy management is always an important issue. In this paper, we study the SCED problem; given a wireless sensor network deployed for watching a composite event x1, x2, … , xM, design a sensor scheduling mechanism such that the set of active sensors ensure the coverage and connectivity conditions and WSN lifetime is maximized. Network lifetime is organized in rounds. Each round has two phases: initialization and data collection. In the initialization phase, the goal is to choose a set of active sensors as sensing nodes or relay nodes such that to achieve both coverage and connectivity requirements. Sensors which are not chosen to be active go to sleep to save energy. In the data collection phase, active sensors perform sensing and data relaying. When another round begins, a new set of active sensors are determined. Two solutions are proposed for the SCED problem, a grid‐based distributed algorithm and a localized algorithm. We analyze their performance through simulations. Copyright © 2010 John Wiley & Sons, Ltd.
Cooperative multiple relay system for frequency selective environment: outage analysis and power allocation
Authors: Haghighi Ali A. , Navaie Keivan
Published: April 2010

In this paper, we propose a novel cooperative relaying scheme with multiple relays for frequency selective wireless environment. In our proposed scheme, the frequency selective wireless channel is divided into flat fading sub‐channels. Cooperative relaying is then employed over each sub‐channel to improve the system diversity order. We then investigate the asymptotic behavior of the outage probability and show that the proposed scheme achieves full diversity order in both amplify and forward (AF) and adaptive decode and forward (ADF) relaying scenarios. Furthermore, we propose a power allocation strategy to minimize the system outage probability. Simulation results confirm our analysis and show that the proposed power allocation method outperforms uniform power allocation. Copyright © 2010 John Wiley & Sons, Ltd.
Aggregate node placement for maximizing network lifetime in sensor networks
Authors: Liang Weifa , Xu Yinlong , Shi Jiugen , Luo Junzhou
Published: April 2010

Sensor networks have been receiving significant attention due to their potential applications in environmental monitoring and surveillance domains. In this paper, we consider the design issue of sensor networks by placing a few powerful aggregate nodes into a dense sensor network such that the network lifetime is significantly prolonged when performing data gathering. Specifically, givenKaggregate nodes and a dense sensor network consisting ofnsensors withK≪n, the problem is to place theKaggregate nodes into the network such that the lifetime of the resulting network is maximized, subject to the distortion constraints that both the maximum transmission range of an aggregate node and the maximum transmission delay between an aggregate node and its covered sensor are met. This problem is a joint optimization problem of aggregate node placement and the communication structure, which is NP‐hard. In this paper, we first give a non‐linear programming solution for it. We then devise a novel heuristic algorithm. We finally conduct experiments by simulation to evaluate the performance of the proposed algorithm in terms of network lifetime. The experimental results show that the proposed algorithm outperforms a commonly used uniform placement schema — equal distance placement schema significantly. Copyright © 2010 John Wiley & Sons, Ltd.
Authenticated key exchange protocol with selectable identities
Authors: Guo Hua , Mu Yi , Zhang Xiyong , Li Zhoujun
Published: April 2010

In the traditional identity‐based cryptography, a user, who holds multiple identities, has to manage multiple private keys, where each private key is associated with an identity. In this paper, we present a key agreement protocol, which allows a single private key to map multiple public keys (identities) that are selectable by the user. That is, the established session key is associated with an arbitrary subset of identities held by the user, while the unselected identities remain secret to other participants. As a bonus, our scheme can be considered as a credential‐based key agreement, where the unique private key can be treated as a credential of the user and the user only proves that his credential is associated with some selected identities. We prove that our scheme is secure in the random oracle model. Copyright © 2010 John Wiley & Sons, Ltd.
New generation of loxP‐mutated deletion cassettes for the genetic manipulation of yeast natural isolates
Authors: Carter Zorana , Delneri Daniela
Published: April 2010

In this work, we developed molecular tools used in standard laboratory yeast strains, such as the cre–loxP system, so that they can be used with natural and industrial prototrophic yeast species. We constructed a new generation of dominant cassettes, with mutated loxP sites (loxLE and lox2272) and selectable drug markers, to create heterothallic strains and auxotrophic mutants without incurring in the risk of generating chromosomal rearrangements. We have shown that our newly developed loxLE–hphNT1–loxRE and lox2272–natNT2–lox2272 gene‐disruption cassettes can be present in the yeast genome together with the widely used loxP–marker gene–loxP cassettes without any recombination between the lox sequences. Moreover, we also developed a new phleomycin‐resistant Cre‐expressing vector (to excise multiple markers simultaneously) and two new standard loxP deletion cassettes containing hygromicin B and cloNAT as selecatable markers. To validate these cassettes, we created heterothallic auxotrophic S. cerevisiae strains, without the risk of incurring gross chromosomal rearrangements, and we showed an example of a fitness study of intraspecific hybrids deriving from parents with different adaptations to carbon‐limited resources. Copyright © 2010 John Wiley & Sons, Ltd.
The dynamic frames theory
Authors: Kassios I. T.
Published: April 2010

The theory of Dynamic Frames has been invented to deal with the frame problem in the presence of encapsulation and pointers. It has proved more flexible and conceptually simpler than previous approaches that tackled the problem. It is now being actively used both for theoretical and for practical purposes related to the formal verification of program correctness. This paper presents the full theory of Dynamic Frames, together with its reasoning laws and exemplifies the use of these laws in proving correct several common design patterns. It also discusses the ongoing research on the topic.
A General Family of Limited Information Goodness-of-Fit Statistics for Multinomial Data
Authors: Joe Harry , Maydeu-Olivares Alberto
Published: April 2010

Maydeu-Olivares and Joe (J. Am. Stat. Assoc. 100:1009–1020, 2005; Psychometrika 71:713–732, 2006) introduced classes of chi-square tests for (sparse) multidimensional multinomial data based on low-order marginal proportions. Our extension provides general conditions under which quadratic forms in linear functions of cell residuals are asymptotically chi-square. The new statistics need not be based on margins, and can be used for one-dimensional multinomials. We also provide theory that explains why limited information statistics have good power, regardless of sparseness. We show how quadratic-form statistics can be constructed that are more powerful than X2 and yet, have approximate chi-square null distribution in finite samples with large models. Examples with models for truncated count data and binary item response data are used to illustrate the theory.
The Consumption of Milk and Dairy Foods and the Incidence of Vascular Disease and Diabetes: An Overview of the Evidence
Authors: Elwood Peter C. , Pickering Janet E. , Givens D. Ian , Gallacher John E.
Published: April 2010

The health effects of milk and dairy food consumption would best be determined in randomised controlled trials. No adequately powered trial has been reported and none is likely because of the numbers required. The best evidence comes, therefore, from prospective cohort studies with disease events and death as outcomes. Medline was searched for prospective studies of dairy food consumption and incident vascular disease and Type 2 diabetes, based on representative population samples. Reports in which evaluation was in incident disease or death were selected. Meta‐analyses of the adjusted estimates of relative risk for disease outcomes in these reports were conducted. Relevant case–control retrospective studies were also identified and the results are summarised in this article. Meta‐analyses suggest a reduction in risk in the subjects with the highest dairy consumption relative to those with the lowest intake: 0.87 (0.77, 0.98) for all‐cause deaths, 0.92 (0.80, 0.99) for ischaemic heart disease, 0.79 (0.68, 0.91) for stroke and 0.85 (0.75, 0.96) for incident diabetes. The number of cohort studies which give evidence on individual dairy food items is very small, but, again, there is no convincing evidence of harm from consumption of the separate food items. In conclusion, there appears to be an enormous mis‐match between the evidence from long‐term prospective studies and perceptions of harm from the consumption of dairy food items.
Small single transmembrane domain (STMD) proteins organize the hydrophobic subunits of large membrane protein complexes
Authors: Zickermann Volker , Angerer Heike , Ding Martina G. , Nübel Esther , Brandt Ulrich
Published: April 2010

The large membrane protein complexes of mitochondrial oxidative phosphorylation are composed of central subunits that are essential for their bioenergetic core function and accessory subunits that may assist in regulation, assembly or stabilization. Although sequence conservation is low, a significant proportion of the accessory subunits is characterized by a common single transmembrane (STMD) topology. The STMD signature is also found in subunits of other membrane protein complexes. We hypothesize that the general function of STMD subunits is to organize the hydrophobic subunits of large membrane protein complexes in specialized environments like the inner mitochondrial membrane.
The mitochondrial permeability transition from yeast to mammals
Authors: Azzolin Luca , von Stockum Sophia , Basso Emy , Petronilli Valeria , Forte Michael A. , Bernardi Paolo
Published: April 2010

Regulated permeability changes have been detected in mitochondria across species. We review here their key features, with the goal of assessing whether a “permeability transition” similar to that observed in higher eukaryotes is present in other species. The recent discoveries (i) that treatment with cyclosporin A (CsA) unmasks an inhibitory site for inorganic phosphate (Pi) [Basso, E., Petronilli, V., Forte, M.A. and Bernardi, P. (2008) Phosphate is essential for inhibition of the mitochondrial permeability transition pore by cyclosporin A and by cyclophilin D ablation. J. Biol. Chem. 283, 26307–26311], the classical inhibitor of the permeability transition of yeast and (ii) that under proper experimental conditions a matrix Ca2+‐dependence can be demonstrated in yeast as well [Yamada, A., Yamamoto, T., Yoshimura, Y., Gouda, S., Kawashima, S., Yamazaki, N., Yamashita, K., Kataoka, M., Nagata, T., Terada, H., Pfeiffer, D.R. and Shinohara Y. (2009) Ca2+‐induced permeability transition can be observed even in yeast mitochondria under optimized experimental conditions. Biochim. Biophys. Acta 1787, 1486–1491] suggest that the mitochondrial permeability transition has been conserved during evolution.
Duality of the carbohydrate‐recognition system of Pseudomonas aeruginosa‐II lectin (PA‐IIL)
Authors: Wu Albert M. , Gong Yu-Ping , Li Chia-Chen , Gilboa-Garber Nechama
Published: April 2010

The study of Pseudomonas aeruginosa‐II lectin (PA‐IIL) complexes with Man derivatives as a recognition factor has been neglected since its monomer is a very weak ligand. Here, the roles of Man oligomers and complexes in PA‐IIL carbohydrate‐recognition were studied by both enzyme‐linked lectinosorbent and inhibition assays. From the results obtained, it is proposed that high density weak –OH conformation as seen in yeast mannan is also an important PA‐IIL recognition factor. This finding provides a peculiar concept of the duality of PA‐IIL recognition system for lFucα1→ and related complexes and for high density Manα1→ complexes present in polymannosylated target macromolecules.
Morbidity and mortality due to unsafe abortion in Pakistan
Authors: Shaikh Zunaira , Abbassi Razia Mustafa , Rizwan Naushaba , Abbasi Sumera
Published: April 2010

Objectives

To determine the frequency of women who had undergone an unsafe abortion and attended a tertiary care hospital in Pakistan with complications.

Methods

Patients with a history of termination at a gestational age of less than or equal to 22 weeks were included in the study.

Results

Of 230 women who met the inclusion criteria, 50 (21.7%) patients had undergone an unsafe abortion and attended the hospital with associated complications. Unintended pregnancy was the reason for the abortion in 82% of women (n = 41). Eighteen (36%) underwent terminations performed by doctors, 18 (36%) by Lady Health Visitors (n = 18), 10 (20%) by an untrained birth attendant (Dai), and 4 (8.0%) by nurses. Dilatation and evacuation procedures were performed in 28 (56.0%) women, while a Laminaria tent prior to evacuation was used in 18 (36.0%). Major complications included uterine perforation and gastrointestinal injury, observed in 27 (54.0%) women. Hemorrhage was observed in 13 (26.0%) women with retained products of conception after incomplete abortion. Six (12.0%) women died.

Conclusion

Healthcare providers performed the majority of terminations. To prevent maternal mortality, improved skills through refresher courses and workshops on safer methods are needed.
Sexual behavior and knowledge of sexually transmitted infections among university students in Sao Paulo, Brazil
Authors: Caetano Maria Eugenia , Linhares Iara Moreno , Pinotti Jose Aristodemo , Maggio da Fonseca Angela , Wojitani Maria Dulce , Giraldo Paulo Cesar
Published: April 2010

Objective

To investigate the sexual behavior and knowledge about sexually transmitted infections (STIs) among undergraduate students in Sao Paulo, Brazil.

Methods

Self‐reported questionnaires were used.

Results

Most of the 447 students in the study were single (97.3%), in their first year of university (87.7%), and the mean ages were 20.4 years (males) and 19.8 years (females). Vaginal intercourse was practiced by 69.7% of males and 48.4% of females, oral sex by 64.5% of males and 43.7% of females, and anal sex by 18.4% of males and 14.1% of females. Use of a condom during vaginal sex was practiced by 80.4% of males and 74.8% of females and during anal sex by 47.8% of males and 30.0% of females. Knowledge of transmission of STIs was greater than 90% for HIV, syphilis, genital herpes, and gonorrhea; 63%–76% for HPV and genital warts; 30%–34% forTrichomonasand only 16% forChlamydia. Only 25%–34% knew that HIV was transmitted by breastfeeding; 56%–60% knew that HIV was transmitted by anal sex.

Conclusion

Many students engage in high‐risk sexual behavior with multiple partners and use condoms inconsistently. Knowledge of the acquisition and modes of sexual and vertical transmission of HIV are strikingly deficient.
Sexual violations among married women in southeastern Nigeria
Authors: Chigbu Chibuike O. , Ekweazi Kingsley E. , Chigbu Chioma C. , Iwuji Stella E.
Published: April 2010

Objective

To investigate domestic sexual violations in southeastern Nigeria and the opinions of married women regarding sexual rights for women.

Method

Married women attending gynecologic clinics at 3 major hospitals in Enugu, Nigeria, completed a structured questionnaire.

Results

A culture of male dominance seemed to be the leading cause for the following high rates: husband's total monopoly on decisions regarding sex, 54.1%; inability to refuse the husband's demands for sex, 60.7%; sex‐related verbal abuse, 39.3%; sex‐related physical violence, 16.2%; and forced sex, 19.1%. Women with a university education and unemployed women reported sexual violations more frequently than did others. Most respondents supported sexual rights for women.

Conclusion

Married women in southeastern Nigeria still are denied sexual rights, apparently owing to a culture of male dominance. A higher education alone may not lead to the advent of sexual rights for women, and a greater emphasis should be placed on societal reorientation.
Viscous fingering of a miscible reactive A + B → C interface: a linear stability analysis
Authors: HEJAZI S. H. , TREVELYAN P. M. J. , AZAIEZ J. , DE WIT A.
Published: April 2010

When one solution of reactant A is displacing another miscible solution of reactant B, a miscible product C can be generated in the contact zone if a simple A + B → C chemical reaction takes place. Depending on the relative effect of A, B and C on the viscosity, different viscous fingering (VF) instabilities can be observed. In this context, a linear stability analysis of this reaction–diffusion–convection problem under the quasi-steady-state approximation is performed to classify the various possible instability scenarios. To do so, we determine the criteria for an instability, obtain dispersion curves both at initial contact time using an analytical implicit solution and at later times via numerical stability analysis. Along with recovering known results for non-reactive systems where the displacement of a more viscous fluid by a less viscous one leads to a VF instability, it is found that in the presence of a chemical reaction, injecting a more viscous fluid into a less viscous fluid can also lead to instabilities. This occurs when the chemical reaction leads to the build up of non-monotonic viscosity profiles. Various instability scenarios are classified in a parameter plane spanned by Rb and Rc representing the log-mobility ratios of the viscosities of the B and C solution respectively with respect to that of the injected solution of A. A parametric study of the influence on stability of the Damköhler number and of the time elapsed after contact of the two reactive solutions is also conducted.
Modelling waving crops using large-eddy simulation: comparison with experiments and a linear stability analysis
Authors: DUPONT S. , GOSSELIN F. , PY C. , DE LANGRE E. , HEMON P. , BRUNET Y.
Published: April 2010

In order to investigate the possibility of modelling plant motion at the landscape scale, an equation for crop plant motion, forced by an instantaneous velocity field, is introduced in a large-eddy simulation (LES) airflow model, previously validated over homogeneous and heterogeneous canopies. The canopy is simply represented as a poroelastic continuous medium, which is similar in its discrete form to an infinite row of identical oscillating stems. Only one linear mode of plant vibration is considered. Two-way coupling between plant motion and the wind flow is insured through the drag force term. The coupled model is validated on the basis of a comparison with measured movements of an alfalfa crop canopy. It is also compared with the outputs of a linear stability analysis. The model is shown to reproduce the well-known phenomenon of ‘honami’ which is typical of wave-like crop motions on windy days. The wavelength of the main coherent waving patches, extracted using a bi-orthogonal decomposition (BOD) of the crop velocity fields, is in agreement with that deduced from video recordings. The main spatial and temporal characteristics of these waving patches exhibit the same variation with mean wind velocity as that observed with the measurements. However they differ from the coherent eddy structures of the wind flow at canopy top, so that coherent waving patches cannot be seen as direct signatures of coherent eddy structures. Finally, it is shown that the impact of crop motion on the wind dynamics is negligible for current wind speed values. No lock-in mechanism of coherent eddy structures on plant motion is observed, in contradiction with the linear stability analysis. This discrepancy may be attributed to the presence of a nonlinear saturation mechanism in LES.
Setting priorities in clinical and health services research: Properties of an adapted and updated method
Authors: Berra Silvina , Sánchez Emília , Pons Joan M. V. , Tebé Cristian , Alonso Jordi , Aymerich Marta
Published: April 2010

Objectives:The objectives of this study is to review the set of criteria of the Institute of Medicine (IOM) for priority-setting in research with addition of new criteria if necessary, and to develop and evaluate the reliability and validity of the final priority score.

Methods:Based on the evaluation of 199 research topics, forty-five experts identified additional criteria for priority-setting, rated their relevance, and ranked and weighted them in a three-round modified Delphi technique. A final priority score was developed and evaluated. Internal consistency, test–retest and inter-rater reliability were assessed. Correlation with experts’ overall qualitative topic ratings were assessed as an approximation to validity.

Results:All seven original IOM criteria were considered relevant and two new criteria were added (“potential for translation into practice”, and “need for knowledge”). Final ranks and relative weights differed from those of the original IOM criteria: “research impact on health outcomes” was considered the most important criterion (4.23), as opposed to “burden of disease” (3.92). Cronbach's alpha (0.75) and test–retest stability (interclass correlation coefficient = 0.66) for the final set of criteria were acceptable. The area under the receiver operating characteristic curve for overall assessment of priority was 0.66.

Conclusions:A reliable instrument for prioritizing topics in clinical and health services research has been developed. Further evaluation of its validity and impact on selecting research topics is required.
Study of progesterone for the prevention of preterm birth in twins (STOPPIT): Findings from a trial-based cost-effectiveness analysis
Authors: Eddama Oya , Petrou Stavros , Regier Dean , Norrie John , MacLennan Graeme , Mackenzie Fiona , Norman Jane E.
Published: April 2010

Objectives: Preterm birth contributes to a range of healthcare problems amongst infants surmounting to sizeable healthcare costs. Twin pregnancies are at particular risk of preterm birth. The objective of this study was to assess the cost-effectiveness of vaginal progesterone gel for the prevention of preterm birth in twin pregnancies.

Methods: An economic evaluation was conducted alongside a randomized placebo controlled trial (the STOPPIT trial) of vaginal progesterone gel for the prevention of preterm birth in twin pregnancies. Five hundred women were recruited from nine maternity hospitals in the United Kingdom. The outcomes of the economic evaluation were presented in terms of net benefit statistics, cost-effectiveness acceptability curves, generated using the nonparametric bootstrap method, and the expected value of perfect information.

Results: Mean health service costs between the period of randomization and discharge for mother and infant were £28,031 in the progesterone group and £25,972 in the placebo group, generating a mean nonsignificant cost difference of £2,059 (bootstrap mean cost difference £2,334; 95 percent confidence interval: −£5,023, £9,142; p = .33). The probability of progesterone being cost-effective was 20 percent at a willingness to pay threshold of £30,000 per preterm birth prevented. There is little economic justification for conducting further research into the use of vaginal progesterone gel in twin pregnancies for the prevention of preterm birth.

Conclusions: Further studies of preventive interventions for preterm birth more generally are required given the scale of the clinical and economic burden of this condition. These studies should be sufficiently powered for economic endpoints and extend beyond hospital discharge.