bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic sensing via ultrasonic excitation
Authors: Yamada Hisato , Takashima Kazuya , Ikushima Kenji , Toida Hiraku , Sato Michitaka , Ishizawa Yoshiichi
Published: May 2013

We present ultrasonic techniques for magnetic measurements. Acoustically modulated magnetization is investigated with sensitive rf detection by narrowband loop antennas. Magnetization on the surface of ferromagnetic metals is temporally modulated with the rf frequency of the irradiated ultrasonic waves, and the near-field components emitted from the focal point of the ultrasonic beam are detected. Based on the principle of the acoustically stimulated electromagnetic (ASEM) response, magnetic sensing and tomography are demonstrated by ultrasonic scanning. We show that ASEM imaging combines good acoustic resolution with magnetic contrast. The sensitivity of this method is estimated to be about 6 G/Hz1/2 in our current setup.
On the transition point of thermally activated conduction of spinel-type MFe2O4 ferrite thin films (M = Zn, Co, Ni)
Authors: Brachwitz K. , Böntgen T. , Lorenz M. , Grundmann M.
Published: May 2013

Thin films of zinc ferrite (ZnFe2O4), cobalt ferrite, and nickel ferrite have been grown on SrTiO3(100) substrates. By changing the growth temperature TG, the electrical conductivity σ of the thin films can be switched from insulating to conducting. An increased lattice constant of thin films grown at low temperatures (e.g., TG(ZnFe2O4)<450 °C) indicates the formation of defects, which seems to promote the hopping conductivity. Temperature-dependent measurements of σ reveal two thermally activated conduction processes. Interestingly, the transition point of these two processes at Tx=107 K−140 K is close to the Verwey transition known from structurally similar magnetite thin films.
Crystal structure and optical characterization of heterostructured GaAs/AlGaAs/GaAs nanowires
Authors: Pusep Yu. A. , Arakaki H. , de Souza C. A. , Rodrigues A. D. , Haapamaki C. M. , LaPierre R. R.
Published: May 2013

Structural and optical properties of heterostructured GaAs/AlGaAs/GaAs core/inner shell/outer shell nanowires are studied. Transmission electron microscopy and Raman scattering measurements unambiguously identify the presence of segments crystallized in zincblende and wurtzite phases, which spread to the shells. Four observed photoluminescence lines are assigned to the radiative recombination of photoexcited electrons confined in the center of the GaAs core and at the heterointerface between the outer GaAs shell and the inner AlGaAs shell with the holes localized at the heterointerface between the core and the inner AlGaAs shell; both recombinations take place in zincblende and wurtzite phases. One additional photoluminescence line is attributed to the spatially indirect recombination between the electrons in zincblende and the holes in wurtzite phases. The bandgap of the wurtzite phase and the band offsets between the zincblende and wurtzite phases are determined.
The effect of composition on pressure-induced devitrification in metallic glasses
Authors: Zeng Qiaoshi , Mao Wendy L. , Sheng Hongwei , Zeng Zhidan , Hu Qingyang , Meng Yue , Lou Hongbo , Peng Fang , Yang Wenge , Sinogeikin Stanislav V. , Jiang Jian-Zhong
Published: May 2013

Long-range topological order (LRTO) was recently revealed in a Ce75Al25 metallic glass (MG) by a pressure-induced devitrification (PID) at 300 K. However, what compositions may have PID and an understanding of the physical and chemical controls behind PID are still not clear. We performed in situ high pressure x-ray diffraction measurements on CexAl1−x (x = 65, 70, and 80 at. %) MGs. Combining our experimental results and simulations, we found PID is very sensitive to compositions and can only exist over narrow compositional ranges. These results provide valuable guidance for searching for PID in MGs.
Enhancements in the lightning impulse breakdown characteristics of natural ester dielectric liquids
Authors: Unge Mikael , Singha Santanu , Van Dung Nguyen , Linhjell Dag , Ingebrigtsen Stian , Lundgaard Lars E.
Published: May 2013

In this letter, we experimentally demonstrate that the lightning impulse breakdown characteristics of natural ester liquids can be significantly enhanced by dispersing molecular additives possessing lower values of both the ionization potential and 1st excitation energies as compared to the base liquid. One such additive contributed to an increase in the breakdown and acceleration voltage of the base liquid by 32% and 90%, respectively. Apart from the expected influence of the low ionization potential of the additives, results also indicate a positive effect of lower value of 1st excitation energy.
Habitat use and ecological observations of the Ooldea dunnart (Sminthopsis ooldea) at Uluru–Kata Tjuta National Park, Northern Territory
Authors: Bennison Kerrie , Dickman Christopher R. , Godfree Robert
Published: May 2013

The Ooldea dunnart (Sminthopsis ooldea) is a small (10–11 g) and poorly known dasyurid marsupial that is endemic to the central and western arid regions of Australia. Surveys carried out at Uluru–Kata Tjuta National Park, Northern Territory, from 1994 to 2010 yielded 37 captures of this elusive species, providing novel insights into its biology. Most captures were made in pitfall traps, with spring breeding confirmed by the presence of pregnant or lactating females during October and November. Animals were captured in mallee and mulga woodland and spinifex (Triodia spp.) dominated dune fields and sand plains. Capture rates were variable in most habitat types, but were relatively consistent in one site dominated by mulga (Acacia aneura). Although we found no consistent association between captures of S. ooldea and prior rainfall, fewest animals were captured in the two wettest years of the study. Ooldea dunnarts showed no clear response to fire. We suggest that mulga is a key habitat for S. ooldea, but also that the demography of this species may be shaped by biotic and/or abiotic factors that remain to be fully elucidated.
Impact of ancestral wheat sodium exclusion genes Nax1 and Nax2 on grain yield of durum wheat on saline soils
Authors: James Richard A. , Blake Carol , Zwart Alexander B. , Hare Ray A. , Rathjen Anthony J. , Munns Rana
Published: May 2013

Nax1 and Nax2 are two genetic loci that control the removal of Na+ from the xylem and thereby help to exclude Na+ from leaves of plants in saline soil. They originate in the wheat ancestral relative Triticum monococcum L. and are not present in modern durum or bread wheat. The Nax1 and Nax2 loci carry TmHKT1;4-A2 and TmHKT1;5-A, respectively, which are the candidate genes for these functions. This paper describes the development of near-isogenic breeding lines suitable for assessing the impact of the Nax loci and their performance in controlled environment and fields of varying salinity. In young plants grown in 150 mM NaCl, Nax1 reduced the leaf Na+ concentration by 3-fold, Nax2 by 2-fold and both Nax1 and Nax2 together by 4-fold. In 250 mM NaCl, Nax1 promoted leaf longevity and greater photosynthesis and stomatal conductance. In the uppermost leaf, the Na+-excluding effect of the Nax loci was much stronger. In the field, Na+ in the flag leaf was reduced 100-fold by Nax1 and 4-fold by Nax2; however, Nax1 lines yielded 5–10% less than recurrent parent (cv. Tamaroi) in saline soil. In contrast, Nax2 lines had no yield penalty and at high salinity they yielded close to 25% more than Tamaroi, indicating this material is suitable for breeding commercial durum wheat with improved yield on saline soils.
IL-15 in tumor microenvironment causes rejection of large established tumors by T cells in a noncognate T cell receptor-dependent manner
Authors: Liu Rebecca Berlant , Engels Boris , Schreiber Karin , Ciszewski Cezary , Schietinger Andrea , Schreiber Hans , Jabri Bana
Published: May 2013

A major challenge of cancer immunotherapy is the persistence and outgrowth of subpopulations that lose expression of the target antigen. IL-15 is a potent cytokine that can promote organ-specific autoimmunity when up-regulated on tissue cells. Here we report that T cells eradicated 2-wk-old solid tumors that expressed IL-15, eliminating antigen-negative cells. In contrast, control tumors that lacked IL-15 expression consistently relapsed. Interestingly, even tumors lacking expression of cognate antigen were rejected when expressing IL-15, indicating that rejection after adoptive T-cell transfer was independent of cognate antigen expression. Nevertheless, the T-cell receptor of the transferred T cells influenced the outcome, consistent with the notion that T-cell receptor activation and effector status determine whether IL-15 can confer lymphokine killer activity-like properties to T cells. The effect was limited to the microenvironment of tumors expressing IL-15; there were no noticeable effects on contralateral tumors lacking IL-15. Taken together, these results indicate that expression of IL-15 in the tumor microenvironment may prevent the escape of antigen loss variants and subsequent tumor recurrence by enabling T cells to eliminate cancer cells lacking cognate antigen expression in a locally restricted manner.
Diversity, host switching and evolution of
Plasmodium vivax
infecting African great apes
Authors: Prugnolle Franck , Rougeron Virginie , Becquart Pierre , Berry Antoine , Makanga Boris , Rahola Nil , Arnathau Céline , Ngoubangoye Barthélémy , Menard Sandie , Willaume Eric , Ayala Francisco J. , Fontenille Didier , Ollomo Benjamin , Durand Patrick , Paupy Christophe , Renaud François
Published: May 2013

Plasmodium vivax
is considered to be absent from Central and West Africa because of the protective effect of Duffy negativity. However, there are reports of persons returning from these areas infected with this parasite and observations suggesting the existence of transmission. Among the possible explanations for this apparent paradox, the existence of a zoonotic reservoir has been proposed. May great apes be this reservoir? We analyze the mitochondrial and nuclear genetic diversity of
P. vivax
parasites isolated from great apes in Africa and compare it to parasites isolated from travelers returning from these regions of Africa, as well as to human isolates distributed all over the world. We show that the
P. vivax
sequences from parasites of great apes form a clade genetically distinct from the parasites circulating in humans. We show that this clade’s parasites can be infectious to humans by describing the case of a traveler returning from the Central African Republic infected with one of them. The relationship between this
P. vivax
clade in great apes and the human isolates is discussed.
Multiple motifs regulate apical sorting of p75 via a mechanism that involves dimerization and higher-order oligomerization
Authors: Youker Robert T. , Bruns Jennifer R. , Costa Simone A. , Rbaibi Youssef , Lanni Frederick , Kashlan Ossama B. , Teng Haibing , Weisz Ora A.
Published: May 2013

The sorting signals that direct proteins to the apical surface of polarized epithelial cells are complex and can include posttranslational modifications, such as N- and O-linked glycosylation. Efficient apical sorting of the neurotrophin receptor p75 is dependent on its O-glycosylated membrane proximal stalk, but how this domain mediates targeting is unknown. Protein oligomerization or clustering has been suggested as a common step in the segregation of all apical proteins. Like many apical proteins, p75 forms dimers, and we hypothesized that formation of higher-order clusters mediated by p75 dimerization and interactions of the stalk facilitate its apical sorting. Using fluorescence fluctuation techniques (photon-counting histogram and number and brightness analyses) to study p75 oligomerization status in vivo, we found that wild-type p75–green fluorescent protein forms clusters in the trans-Golgi network (TGN) but not at the plasma membrane. Disruption of either the dimerization motif or the stalk domain impaired both clustering and polarized delivery. Manipulation of O-glycan processing or depletion of multiple galectins expressed in Madin-Darby canine kidney cells had no effect on p75 sorting, suggesting that the stalk domain functions as a structural prop to position other determinants in the lumenal domain of p75 for oligomerization. Additionally, a p75 mutant with intact dimerization and stalk motifs but with a dominant basolateral sorting determinant (Δ250 mutant) did not form oligomers, consistent with a requirement for clustering in apical sorting. Artificially enhancing dimerization restored clustering to the Δ250 mutant but was insufficient to reroute this mutant to the apical surface. Together these studies demonstrate that clustering in the TGN is required for normal biosynthetic apical sorting of p75 but is not by itself sufficient to reroute a protein to the apical surface in the presence of a strong basolateral sorting determinant. Our studies shed new light on the hierarchy of polarized sorting signals and on the mechanisms by which newly synthesized proteins are segregated in the TGN for eventual apical delivery.
Candidate super star cluster progenitor gas clouds possibly triggered by close passage to Sgr A*
Authors: Longmore S. N. , Kruijssen J. M. D. , Bally J. , Ott J. , Testi L. , Rathborne J. , Bastian N. , Bressert E. , Molinari S. , Battersby C. , Walsh A. J.
Published: May 2013

Super star clusters are the end product of star formation under the most extreme conditions. As such, studying how their final stellar populations are assembled from their natal progenitor gas clouds can provide strong constraints on star formation theories. An obvious place to look for the initial conditions of such extreme stellar clusters is gas clouds of comparable mass and density, with no star formation activity. We present a method to identify such progenitor gas clouds and demonstrate the technique for the gas in the inner few hundred pc of our Galaxy. The method highlights three clouds in the region with similar global physical properties to the previously identified extreme cloud, G0.253 + 0.016, as potential young massive cluster (YMC) precursors. The fact that four potential YMC progenitor clouds have been identified in the inner 100 pc of the Galaxy, but no clouds with similar properties have been found in the whole first quadrant despite extensive observational efforts, has implications for cluster formation/destruction rates across the Galaxy. We put forward a scenario to explain how such dense gas clouds can arise in the Galactic Centre environment, in which YMC formation is triggered by gas streams passing close to the minimum of the global Galactic gravitational potential at the location of the central supermassive black hole, Sgr A*. If this triggering mechanism can be verified, we can use the known time interval since closest approach to Sgr A* to study the physics of stellar mass assembly in an extreme environment as a function of absolute time.
Pathogenicity, Virulence, and Vegetative Compatibility Grouping of Verticillium Isolates from Spinach Seed
Authors: Iglesias-Garcia Angela M. , Villarroel-Zeballos Maria I. , Feng Chunda , Toit Lindsey J. du , Correll James C.
Published: May 2013

In 2005, Verticillium dahliae was first reported to be pathogenic to spinach seed crops in the Pacific Northwest, with symptoms only developing after initiation of the reproductive stage of plant growth, and to be prevalent on commercial spinach seed lots produced in Denmark, The Netherlands, and the United States. In this study, the genetic diversity, pathogenicity, and virulence were examined for a collection of isolates of Verticillium spp. from spinach as well as other hosts (alfalfa, cotton, lettuce, mint, peppermint, potato, radish, and tomato) from various countries and from different vegetative compatibility groups (VCGs). Of a total of 210 isolates of V. dahliae obtained from spinach seed produced in Denmark, the Netherlands, New Zealand, or the United States, 128 were assigned to VCG 4B (89% of 91 U.S. isolates, 86% of 42 isolates from the Netherlands, 19% of 43 Denmark isolates, and 8% of 13 New Zealand isolates), 65 to VCG 2B (92% of the New Zealand isolates, 79% of the Denmark isolates, 14% of the Netherlands isolates, and 9% of the U.S. isolates), and 3 to VCG 2A (2% of each of the Denmark and U.S. isolates, and 0% of the Netherlands and New Zealand isolates); 14 isolates could not be assigned to a VCG. Although little variation in the sequence of the internal transcribed spacer (ITS) region of ribosomal DNA was observed among isolates within each Verticillium sp., the ITS region readily differentiated isolates of the species V. dahliae, V. tricorpus, and Gibellulopsis nigrescens (formerly V. nigrescens) obtained from spinach seed. Greenhouse pathogenicity assays on spinach, cotton, lettuce, and tomato plants using isolates of V. dahliae (n = 29 to 34 isolates), V. tricorpus (n = 3), G. nigrescens (n = 2), and V. albo-atrum (n = 1) originally obtained from these hosts as well as from alfalfa, mint, peppermint, potato, and radish, revealed a wide range in virulence among the isolates. Isolates of V. tricorpus and G. nigrescens recovered from spinach seed and an isolate of V. albo-atrum from alfalfa were not pathogenic on spinach. In addition, isolates of V. dahliae from mint and peppermint were not pathogenic or only weakly virulent on the hosts evaluated. Although there was a wide range in virulence among the isolates of V. dahliae tested, all of the V. dahliae isolates caused Verticillium wilt symptoms on spinach, lettuce, tomato, and cotton. None of the isolates of V. dahliae showed host specificity. These results indicate that Verticillium and related species associated with spinach seed display substantial variability in virulence and pathogenicity to spinach and other plants but the V. dahliae isolates were restricted to three VCGs.
Occurrence of Grapevine Leafroll-Associated Viruses in China
Authors: Liu M.-H. , Li M.-J. , Qi H.-H. , Guo R. , Liu X.-M. , Wang Q. , Cheng Y.-Q.
Published: May 2013

To characterize the prevalence of viruses associated with grapevine leafroll disease in China, 249 grapevine (Vitis spp.) samples (86 popular cultivars and a rootstock) from 19 provinces and regions were collected and tested for Grapevine leafroll-associated virus 1 (GLRaV-1), GLRaV-2, GLRaV-3, GLRaV-4, and GLRaV-4 strain 5 by SYBR Green real-time reverse-transcription polymerase chain reaction (RT-PCR), and RT-PCR and sequencing. GLRaV-3 was found in 100% of the samples while GLRaV-1, GLRaV-2, and GLRaV-4 were detected in 24.9% (62/249), 15.3% (38/249), and 0.80% (2/249) of the samples, respectively. Single infections with GLRaV-3 were found in 66.3% (165/249) of the samples, and the remaining samples were mixed infections of GLRaV-3 with one or two other GLRaVs, those with GLRaV-1 being the most common (18.5%, 46/249). The genetic variability of Chinese GLRaV-3 isolates was characterized based on the coat protein (CP) gene. In total, 153 full-length CP gene sequences (94 sequences newly generated) of Chinese GLRaV-3 isolates from different grapevine-growing regions showed 89.3 to 100.0% and 92.7 to 100.0% identity at the nucleotide and amino acid levels, respectively. The average nucleotide diversity for the population of Chinese GLRaV-3 isolates was estimated at 0.037 (standard error = 0.0032). GLRaV-3 isolates from China segregated into five distinct phylogenetic groups and two novel recombination events were found in the viral population. This is the first and most extensive report of the prevalent species of GLRaV in China, which also provides an assessment of genetic variability of GLRaV-3 Chinese isolates.
Rust Fungi Forming Aecia on Berberis spp. in Sweden
Authors: Berlin A. , Kyaschenko J. , Justesen A. F. , Yuen J.
Published: May 2013

Barberry (Berberis spp.) hosts the aecial stage of several rust species, including Puccinia graminis, which causes stem rust on grasses and cereals. The aecial stage of this pathogen has received less attention because it is not as economically important compared with the uredinial and telial stages. The main objective of this study was to identify and describe the rust species that were found on Berberis spp. collected in different parts of Sweden. A morphological study, including spore measurements and aecia descriptions, was conducted, as well as DNA sequence analyses (using the internal transcribed spacer region and the EF1-α gene). Based on spore and aecia morphology as well as the genetic analyses, three different taxa could be distinguished on barberry: P. graminis f. sp. avenae, P. graminis f. sp. tritci/secalis, and P. arrhenatheri. The genetic analysis revealed little or no differentiation between P. graminis f. sp. tritici and P. graminis f. sp. secalis and, thus, this group of samples was denominated P. graminis f. sp. tritici/secalis. Aecial morphology may be used to differentiate between different taxa. In particular, examination of aecial cross-sections may be used to distinguish between P. graminis f. sp. avenae and P. graminis f. sp. tritici/secalis. A clear differentiation in the mode of growth on barberry was also found; P. arrhenatheri always appeared systemic whereas P. graminis always appeared localized.
Evolutionary cell biology of chromosome segregation: insights from trypanosomes
Authors: Akiyoshi Bungo , Gull Keith
Published: May 2013

Faithful transmission of genetic material is essential for the survival of all organisms. Eukaryotic chromosome segregation is driven by the kinetochore that assembles onto centromeric DNA to capture spindle microtubules and govern the movement of chromosomes. Its molecular mechanism has been actively studied in conventional model eukaryotes, such as yeasts, worms, flies and human. However, these organisms are closely related in the evolutionary time scale and it therefore remains unclear whether all eukaryotes use a similar mechanism. The evolutionary origins of the segregation apparatus also remain enigmatic. To gain insights into these questions, it is critical to perform comparative studies. Here, we review our current understanding of the mitotic mechanism inTrypanosoma brucei, an experimentally tractable kinetoplastid parasite that branched early in eukaryotic history. No canonical kinetochore component has been identified, and the design principle of kinetochores might be fundamentally different in kinetoplastids. Furthermore, these organisms do not appear to possess a functional spindle checkpoint that monitors kinetochore–microtubule attachments. With these unique features and the long evolutionary distance from other eukaryotes, understanding the mechanism of chromosome segregation inT. bruceishould reveal fundamental requirements for the eukaryotic segregation machinery, and may also provide hints about the origin and evolution of the segregation apparatus.
Multiple effects of dendritic cell depletion on murine norovirus infection
Authors: Elftman Michael D. , Gonzalez-Hernandez Mariam B. , Kamada Nobuhiko , Perkins Cheryl , Henderson Kenneth S. , Núñez Gabriel , Wobus Christiane E.
Published: May 2013

Dendritic cells (DCs) are permissive to murine norovirus (MNV) infection in vitro and in vivo. However, their roles during infection in vivo are not well defined. To determine the role of DCs during infection, conventional DCs were depleted from CD11c-DTR mice and infected with a persistent MNV strain. Viral titres in the intestine and secondary lymphoid organs were determined at early time points during infection, and anti-MNV antibody responses were analysed later during infection. Depletion of conventional DCs resulted in increased viral loads in intestinal tissues, impaired generation of antibody responses, and a failure of MNV to efficiently infect lymphoid tissues. These data suggest that DCs play multiple roles in MNV pathogenesis, in both innate immunity and the efficient generation of adaptive immune responses against MNV, as well as by promoting the dissemination of MNV to secondary lymphoid tissues. This is the first study to probe the roles of DCs in controlling and/or facilitating a norovirus infection in vivo and provides the basis for further studies aimed at defining mechanisms by which DCs control MNV replication and promote viral dissemination.
Effect of blast cleaning parameters on corrosion of brass parts
Authors: Masmoudi N. , Khlif M.
Published: May 2013

Purpose

The purpose of this present work is to investigate how different parameters of the blast cleaning process affect properties and quality of brass parts surface. It aims to study the following process variables: particle abrasive shape: (spherical (S) and angular (G) shot), particle abrasive size (S170, G40 and G50) and the impact velocity (40 m/s, 60 m/s and 80 m/s).

Design/methodology/approach

An experimental approach based on three testing methods is used to quantify the analysis of particulate contaminants on substrates surfaces. These methods are: SEM, BSEM and EDXA plots from SEM imaging.

Findings

The results obtained clearly show that the particle embedment decreases with decreasing of the size of angular abrasive. An increase in the embedment could be noted as impact velocity increased. It was also found that the angular abrasives have delivered a contamination level higher than that delivered by spherical abrasives. Furthermore, it was demonstrated that the abrasive debris nature embedded in the treated surfaces is the iron. The coupling of this debris with the base metal (copper) in the presence of wetland causes an electrochemical corrosion. Then, if the contamination level decreases, the corrosion rate in treated brass parts by steel shots decreases also.

Originality/value

Search in the case of blast cleaning for the brass parts by steel shots has not been done previously. Using the spherical shape of the abrasive projected with a moderate impact velocity will be a solution in this case.
Effect of size‐distributed bubbles on acoustic properties of an elastic tube with polymeric liquid
Authors: Levitsky Semyon , Bergman Rudolf , Haddad Jehuda
Published: May 2013

Purpose

The objective of this study is to model the influence of free gas, in the form of size‐distributed fine bubbles, on sound attenuation and dispersion in a thin‐walled elastic cylindrical tube filled with viscoelastic polymeric liquid.

Design/methodology/approach

Sound wave propagation in the system is described within a three‐phase interaction scheme, based on a quasi‐homogeneous approach to liquid‐gas mixture dynamics in the wave. Coupled equations of tube wall deformations and viscoelastic liquid dynamics in the tube are solved using a long‐wave approximation. The dissipative losses, stemming from flow gradients in the wave, as well as from non‐equilibrium bubble‐liquid interaction, are accounted for. The dispersion equation for the waveguide is obtained and studied numerically.

Findings

The results of the study indicate that bubble‐size distribution in viscoelastic liquid has an essential impact on sound propagation in the tube at sufficiently high frequencies. The frequency range in which the mixture heterogeneity influences the acoustic properties of the system is sensitive to both the distribution parameters and the rheological properties of the liquid. As distinct to polydispersity features, the viscoelastic properties of liquid are also relevant in the low‐frequency range, where they lead to an increase of the wave speed and a decrease of its attenuation.

Originality/value

A model of sound wave propagation in a tube filled with a heterogeneous viscoelastic liquid‐bubble mixture is formulated. The study provides a basis for modeling transient processes in tubes filled with polymeric liquids containing free gas, and for acoustic control of certain processes in polymer technologies.
Performance study of various tool materials for electrical discharge machining of hot pressed ZrB2
Authors: Sivasankar S. , Jeyapaul R. , Bhanu Prasad V.V.
Published: May 2013

Purpose

This study aims to explore the machinability of ZrB2 using electrical discharge machining (EDM) with different tool materials.

Design/methodology/approach

The workpiece for this study was fabricated through powder metallurgy compaction method. The disc is machined using diamond load grinding to have parallel surfaces, then, 2 mm diameter holes are machined on the disc using EDM spark erosion machine with different tool materials (graphite, aluminium, tantalum, niobium, copper, brass, silver, tungsten and titanium). Roundness, geometry of hole, and diameter of the hole at different diametric planes, surface roughness (SR), material removal rate (MRR), tool wear rate (TWR), taper angle and recast layer (RCL) thickness are measured. The photographic analysis of tools, holes in the top view, bottom view and sectional view. SEM analysis was conducted to study the recast layer. Desirability function analysis was employed to rate the performances of tools.

Findings

A new theory is developed which relates recast layer thickness with melting point and thermal conductivity of the tool materials. Machining of ZrB2 by EDM is feasible; graphite is identified as the best tool. Recast layer thickness of the machined surfaces are indirectly proportional to the product of melting point and thermal conductivity of tool. Ablation behaviour of ceramic workpiece lead additional material losses in the tool.

Originality/value

Extremely high strength and hardness of ZrB2 due to the coexistence of strong covalent and metallic bond make mechanical machining very difficult or even impossible. No machinability studies were conducted previously on ZrB2 using EDM; this work reveals machinability study of ZrB2 with different tool materials.
Fluid‐structure interaction computational analysis of a piston‐cylinder based blast‐wave‐mitigation concept
Authors: Grujicic M. , Snipes J.S. , Chandrasekharan N.
Published: May 2013

Purpose

This paper aims to utilize purpose advanced fluid‐structure interaction, non‐linear dynamics, finite‐element analyses in order to investigate various phenomena and processes accompanying blast wave generation, propagation and interaction and to assess the blast‐wave‐mitigation potential of a piston‐cylinder assembly placed in front of the target structure.

Design/methodology/approach

The employed computational methods and tools are verified and validated by first demonstrating that they can quite accurately reproduce analytical solutions for a couple of well‐defined blast wave propagation and interaction problems.

Findings

The methods/tools are used to investigate the piston‐cylinder blast‐mitigation concept and the results obtained clearly reveal that significant blast‐mitigation effects can be achieved through the use of this concept. Furthermore, the results showed that the extent of the blast‐mitigation effect is a sensitive function of the piston‐cylinder geometrical parameters. Specifically, the mass of the piston and the length of the cylinder are found to be the dominant factors controlling the extent of the blast‐wave‐mitigation.

Originality/value

The work demonstrates that, when assessing the blast‐wave‐mitigation potential of the piston‐cylinder concept, it is critical that loading experienced by the piston be defined by explicitly modeling (fluid/structure) interactions between the blast wave(s) and the piston.
Changes in risk factors for preterm birth in Western Australia 1984–2006
Authors: Hammond G , Langridge A , Leonard H , Hagan R , Jacoby P , DeKlerk N , Pennell C , Stanley F
Published: May 2013

Objective

To characterise changing risk factors of preterm birth in Western Australia between 1984 and 2006.

Design

Population‐based study.

Setting

Western Australia.

Population

All non‐Aboriginal women giving birth to live singleton infants between 1984 and 2006.

Methods

Multinomial, multivariable regression models were used to assess antecedent profiles by preterm status and labour onset types (spontaneous, medically indicated, prelabour rupture of membranes [PROM]). Population attributable fraction (PAF) estimates characterized the contribution of individual antecedents as well as the overall contribution of two antecedent groups: pre‐existing medical conditions (including previous obstetric history) and pregnancy complications.

Main outcome measure

Antecedent relationships with preterm birth, stratified by labour onset type.

Results

Marked increases in maternal age and primiparous births were observed. A four‐fold increase in the rates of pre‐existing medical complications over time was observed. Rates of pregnancy complications remained stable. Multinomial regression showed differences in antecedent profiles across labour onset types. PAF estimates indicated that 50% of medically indicated preterm deliveries could be eliminated after removing six antecedents from the population; estimates for PROM and spontaneous preterm reduction were between 10 and 20%. Variables pertaining to previous and current obstetric complications (previous preterm birth, previous caesarean section, pre‐eclampsia and antepartum haemorrhage) were the most influential predictors of preterm birth and adverse labour onset (PROM and medically indicated).

Conclusions

Preterm antecedent profiles have changed markedly over the 23 years studied. Some changes may be attributable to true change, others to advances in surveillance and detection. Still others may signify change in clinical practice.
Development of Novel Methods to Determine Crystalline Glucose Content of Honey Based on DSC, HPLC, and Viscosity Measurements, and Their Use to Examine the Setting Propensity of Honey
Authors: Al‐Habsi Nasser A. , Davis Fred J. , Niranjan Keshavan
Published: May 2013

Crystallization must occur in honey in order to produce set or creamed honey; however, the process must occur in a controlled manner in order to obtain an acceptable product. As a consequence, reliable methods are needed to measure the crystal content of honey (ϕ expressed as kg crystal per kg honey), which can also be implemented with relative ease in industrial production facilities. Unfortunately, suitable methods do not currently exist. This article reports on the development of 2 independent offline methods to measure the crystal content in honey based on differential scanning calorimetry and high‐performance liquid chromatography. The 2 methods gave highly consistent results on the basis of paired t‐test involving 143 experimental points (P > 0.05, r2 = 0.99). The crystal content also correlated with the relative viscosity, defined as the ratio of the viscosity of crystal containing honey to that of the same honey when all crystals are dissolved, giving the following correlation: . This correlation can be used to estimate the crystal content of honey in industrial production facilities. The crystal growth rate at a temperature of 14 °C—the normal crystallization temperature used in practice—was linear, and the growth rate also increased with the total glucose content in the honey.
SP‐Designer: a user‐friendly program for designing species‐specific primer pairs from DNA sequence alignments
Authors: Villard Pierre , Malausa Thibaut
Published: May 2013

SP‐Designer is an open‐source program providing a user‐friendly tool for the design of specific PCR primer pairs from a DNA sequence alignment containing sequences from various taxa. SP‐Designer selects PCR primer pairs for the amplification of DNA from a target species on the basis of several criteria: (i) primer specificity, as assessed by interspecific sequence polymorphism in the annealing regions, (ii) the biochemical characteristics of the primers and (iii) the intended PCR conditions. SP‐Designer generates tables, detailing the primer pair and PCR characteristics, and a FASTA file locating the primer sequences in the original sequence alignment. SP‐Designer is Windows‐compatible and freely available from http://www2.sophia.inra.fr/urih/sophia_mart/sp_designer/info_sp_designer.php.
Knockout of 5‐lipoxygenase prevents dexamethasone‐induced tau pathology in 3xTg mice
Authors: Joshi Yash B. , Chu Jin , Praticò Domenico
Published: May 2013

Emerging evidence suggests that dysregulation stress hormones, such as glucocorticoids, in aged persons put them at a higher risk to develop Alzheimer's disease (AD). However, the mechanisms underlying such vulnerability remain to be unraveled. Pharmacologic inhibition of 5‐lipoxygenase (5LO), an active player in AD pathogenesis whose protein level increases with aging in the human, has been shown to blunt glucocorticoid‐mediated amyloid β (Ab) formation in vitro. In this article, we investigated the role of this pathway in modulating the development of the corticosteroid‐dependent AD‐like phenotype in the triple transgenic mice (3xTg). Dexamethasone was administered for 1 week to 3xTg or 3xTg genetically deficient for 5LO (3xTg/5LO−/−) mice, and its effect on memory, amyloid‐β and tau levels, and metabolism assessed. At the end of the treatment, we observed that dexamethasone did not induce changes in behavior. Compared with controls, treated mice did not show significant alterations in brain soluble Aβ levels. While total tau protein levels were unmodified in all groups, we found that dexamethasone significantly increased tau phosphorylation at S396, as recognized by the antibody PHF‐13, which was specifically associated with an increase in the GSK3β activity. Additionally, dexamethasone‐treated mice had a significant increase in the tau insoluble fraction and reduction in the postsynaptic protein PDS‐95. By contrast, these modifications were blunted in the 3xTg/5LO−/− mice. Our findings highlight the functional role that 5LO plays in stress‐induced AD tau pathology and support the hypothesis that pharmacologic inhibition of this enzyme could be a useful tool for individuals with this risk factor.
The Informative Power of Treaty Commitment: Using the Spatial Model to Address Selection Effects
Authors: Lupu Yonatan
Published: May 2013

The effects of international institutions on state behavior make up a key research agenda in international‐relations scholarship. Because states self‐select into treaties, we cannot infer that these commitments have causal effects unless we address this selection effect. I explain the significant limitations of the methods used thus far to overcome this problem and argue that a more effective approach must take into account states’ treaty preferences. I describe a novel combination of ideal‐point estimation and propensity‐score matching that can estimate the probabilities of treaty commitment and use them to test hypotheses. I use this procedure to test the effects of three key international human‐rights treaties. My results provide significant new findings regarding the effects of these important agreements. I show that the Convention on the Elimination of All Forms of Discrimination against Women has significantly improved respect for women's rights, but that the Convention against Torture and the International Covenant on Civil and Political Rights have not had significant effects on human rights.
Evaluation of Suction Detection During Different Pumping States in an Implantable Rotary Blood Pump
Authors: Ng Siew‐Cheok , Lim Einly , Mason David G. , Avolio Alberto P. , Lovell Nigel H.
Published: May 2013

In recent times, the problem of noninvasive suction detection for implantable rotary blood pumps has attracted substantial research interest. Here, we compare the performance of various suction indices for different types of suction and non‐suction events based on pump speed irregularity. A total of 171 different indices that consist of previously proposed as well as newly introduced suction indices are tested using regularized logistic regression. These indices can be classified as amplitude based (derived from the mean, maximum, and minimum values of a cycle), duration based (derived from the duration of a cycle), gradient based (derived from the first order as well as higher order differences) and frequency based (derived from the power spectral density). The non‐suction event data consists of ventricular ejection with or without arrhythmia and intermittent and continuous non‐opening of the aortic valve. The suction event data consists of partial ventricular collapse that occurs intermittently as well as continuously with or without arrhythmia. In addition, we also attempted to minimize the usage of multiple indices by applying the sequential forward floating selection method to find which combination of indices gives the best performance. In general, the amplitude‐based and gradient‐based indices performed quite well while the duration‐based and frequency‐based indices performed poorly. By having only two indices ([i] the maximum gradient change in positive slope; and [ii] the standard deviation of the maximum value in a cycle), we were able to achieve a sensitivity of 98.9% and a specificity of 99.7%.
Dyslipidemia Is Associated With Tunneled‐Cuffed Catheter‐Related Central Venous Thrombosis in Hemodialysis Patients: A Retrospective, Multicenter Study
Authors: Cheng Yuan , Cui Tianlei , Fu Ping , Liu Fang , Zhou Li
Published: May 2013

The aim of this study was to explore the risk factors of tunneled‐cuffed catheter (TCC)‐related central venous thrombosis (CVT) for the maintenance of hemodialysis patients. In this study, 285 patients on maintenance hemodialysis were enrolled who had received their first TCC in the right jugular vein. Patients were divided into CVT and control groups according to the diagnosis of TCC‐related CVT 6 months after catheterization. Patients with CVT had a higher prevalence of dyslipidemia (50.74 vs. 26.85%, respectively) and low protein store compared with the control group. After adjusting for confounders, serum triglycerides (OR: 3.632; 95% CI: 2.105–6.267), non‐HDL cholesterol (OR: 1.463; 95% CI:1.067–2.007), and low‐density lipoprotein/high‐density lipoprotein (LDL/HDL) cholesterol ratio (OR: 2.904; 95% CI: 1.797–4.692) were positively correlated with TCC‐related CVT, while serum HDL cholesterol (OR: 0.097; 95% CI: 0.037–0.257) and serum albumin (OR: 0.922; 95% CI: 0.864–0.985) were negatively correlated. Dyslipidemia and low serum albumin levels were significantly associated with TCC‐related CVT in hemodialysis patients.
Effects of exclusive breastfeeding intervention on child growth and body composition: theMINIMat trial,Bangladesh
Authors: Khan Ashraful I , Hawkesworth Sophie , Ekström Eva‐Charlotte , Arifeen Shams , Moore Sophie E , Frongillo Edward A , Yunus Md , Persson Lars Å , Kabir Iqbal
Published: May 2013

Aim

Exclusive breastfeeding (EBF) for 6 months is recommended for optimal infant health, but the evidence for longer‐term impacts is weak. We examined whether randomization to receiveEBFcounselling (BFC) in ruralBangladeshi women had an impact on childhood growth trajectories and body composition.

Methods

In the Maternal and Infant Nutrition Interventions in Matlab trial, 4436 pregnant women were randomized to six equally sized, food and micronutrient groups. Of these, 3214 were randomized during the last trimester of pregnancy to receive eitherBFCor the usual/standard health message (UHM). Their infants were extensively followed up, with anthropometric measurements between 0 and 54 months and assessment of body composition at 54 months.

Results

The mean duration ofEBFin theBFCgroup was 111 days compared to 76 days in theUHMgroup (mean difference: 35.0 days, 95%CI30.6–39.5, p < 0.001). There was no difference in growth trajectories between theBFCandUHMgroups and no difference in body composition at 54 months. Children exposed to prenatal multiple micronutrients (vs 60 mg iron and folate) combined withBFC(vsUHM), however, had slower linear growth (mean difference −0.17SDscore, p < 0.01).

Conclusion

Exclusive breastfeeding counselling resulted in neither differential growth trajectories in infancy and childhood, nor body composition differences at 54 months. The combination of prenatal multiple micronutrient supplementation (MMS) andBFCwas unfavourable for linear growth during 0–54 months, which raises questions about possible negative effects ofMMS.
INCENTIVE AND INSURANCE EFFECTS OF INCOME TAXATION
Authors: Andersen Torben M.
Published: May 2013

Tax distortions cause a trade‐off between efficiency and equity. However, taxes not only affect incentives; they also provide implicit insurance, and this may critically affect the efficiency–equity relationship. For a standard labour supply problem it is shown that the insurance effect mutes the sensitivity of labour supply to taxes, which tends to reduce tax distortions and lower the marginal costs of public funds. The relation between incentives and insurance and thus efficiency and equity is flattened by the insurance effect and it may even be non‐monotone. However, the optimal utilitarian policy implies that there is always a trade‐off between efficiency and equity on the margin.
NKG2D blockade attenuated cardiac allograft vasculopathy in a mouse model of cardiac transplantation
Authors: Chen H , Xia J , Zhang L , Jin X , Yang M , Li J , Zhao Y
Published: May 2013

A previous paper has reported that blockade of NKG2D was effective in protecting allograft in murine models of cardiac transplantation, but the mechanism of NKG2D blockade on attenuated cardiac allograft vasculopathy (CAV) was still unknown. In our current study, we found that wild-type recipients treated with anti-NKG2D monoclonal antibody (mAb) plus cytotoxic T lymphocyte antigen (CTLA)-4-immunoglobulin (I)g showed prolonged allograft survivals (>90 days, P < 0·001) significantly and attenuated CAV. These in-vivo results correlated with reduced alloantibody production, low expression of interleukin (IL)-17 and IL-6, while infiltration of regulatory T cells increased. IL-6 administration induced shorter allograft survival and higher CAV grade in CTLA-4–Ig plus anti-NKG2D mAb-treated recipients, whereas IL-17 had no significant effect on allograft survival and CAV grade in CTLA-4–Ig plus anti-NKG2D mAb-treated recipients. Furthermore, the prolonged allograft survival induced by NKG2D blockade was abrogated partially with depletion of regulatory T cells. In conclusion, blockade of NKG2D combined with CTLA-4–Ig attenuated CAV and this effect was associated with lower alloantibody production, inhibited IL-6 expression and enhanced expansion of regulatory T cells.