bluuebunny/crossref_metadata_2025 huggingface dataset:
Longitudinal Follow-up of Poor Inner-city Youth Between Ages 8 and 18: Intentions Versus Reality
Authors: Handzel Jennifer M. , Brodsky Nancy , Betancourt Laura , Hurt Hallam
Published: February 2012

OBJECTIVES:

(1) To document, at ages 8 to 10, children’s perceptions of their future and, at ages 16 to 18, youth outcomes; and (2) to assess early childhood factors associated with trajectory-altering events (TAEs), defined as youth risk behaviors that may modify developmental trajectories.

METHODS:

A prospective longitudinal study of 97 poor, inner-city, African American youth followed since birth who completed (1) early childhood environment, cognitive, and social-emotional evaluations, as well as an inventory at ages 8 to 10 of perceptions of their futures; and (2) evaluation for presence or absence of 4 TAEs documented at ages 16 to 18: drug use, adjudication, school failure, and teen parenthood.

RESULTS:

At age 9.4 ± 0.5, 94% of participants felt it unlikely they would try marijuana; 93% felt they were unlikely to get arrested; 92% felt they were likely to attend college or trade school; 81% did not know one could become pregnant with first-time sex. Age 18.1 ± 0.8 outcomes showed that 33% had used drugs, 33% had been adjudicated, 19% had school failure, and 20% had become parents. Fifty-six percent had ≥1 TAE. No relationship was found between childhood perceptions and intentions and documented outcomes. Odds of having a TAE increased with greater exposure to violence and poorer home environment.

CONCLUSIONS:

Young inner-city children are idealistic regarding their future. By ages 16 to 18 however, more than half of this cohort had a TAE. Factors most strongly associated with a TAE were greater exposure to violence and poorer home environment.
Impaired Fetal Growth and Arterial Wall Thickening: A Randomized Trial of Omega-3 Supplementation
Authors: Skilton Michael R. , Ayer Julian G. , Harmer Jason A. , Webb Karen , Leeder Stephen R. , Marks Guy B. , Celermajer David S.
Published: February 2012

OBJECTIVES:

Impaired fetal growth is an independent cardiovascular risk factor and is associated with arterial wall thickening in children. No preventive strategy has been identified. We sought to determine whether dietary omega-3 fatty acid supplementation during early childhood prevents the association between impaired fetal growth and carotid arterial wall thickening.

METHODS:

The Childhood Asthma Prevention Study was a randomized, controlled single-blind trial in 616 children born at term, recruited antenatally from maternity hospitals in Sydney. Participants were randomized to either a 500-mg-daily fish oil supplement and canola-based margarines and cooking oil (omega-3 group), or a 500-mg-daily sunflower oil supplement and omega-6 fatty acid–rich margarines and cooking oil (control group), from the start of bottle-feeding or 6 months of age until 5 years of age. Carotid intima-media thickness (IMT), a noninvasive measure of subclinical atherosclerosis, was the primary endpoint of a cardiovascular substudy (CardioCAPS) at age 8 years. We examined the association of fetal growth with carotid IMT in children with birth weight <90th percentile (omega-3 group [n = 187], control group [n = 176]).

RESULTS:

In the control group, fetal growth was inversely associated with carotid IMT, but this was prevented in the omega-3 group (difference between groups of 0.041 mm [95% confidence interval 0.006, 0.075] per kg birth weight, adjusted for gestational age and gender, Pheterogeneity = .02).

CONCLUSIONS:

The inverse association of fetal growth with arterial wall thickness in childhood can be prevented by dietary omega-3 fatty acid supplementation over the first 5 years of life.
The prevalence of atrial fibrillation in Hungary
Authors: Tomcsányi János , Bózsik Béla , Rokszin György , Abonyi-Tóth Zsolt , Katona Lajos
Published: February 2012

To estimate the prevalence and incidence of atrial fibrillation in the entire population of Hungary. Methods: Analysis of the National Health Insurance Fund Administration database between 2007 and 2009 considering data from 2002. We assumed that patients with atrial fibrillation would turn to health care providers at least once either as outpatients or inpatients in a 5-year period. The National Health Insurance Patient Registry was used to assess the true number of patient visits. Results: The prevalence of atrial fibrillation in Hungary is between 2.37–2.67%. Each year, only about half of these patients seek medical advice. Conclusions: Our survey seems to be the first epidemiological study that aims at estimating the prevalence of atrial fibrillation in the total population of our country. Using a time frame of five to seven years, the prevalence of atrial fibrillation in the total population is significantly higher than it was estimated earlier. However, by using a mathematical model, an even higher prevalence rate of atrial fibrillation (2.95%) was calculated for the total population of Hungary. Orv. Hetil., 2012, 153, 339–342.
Thermite Initiation Processes and Thresholds
Authors: Johnson Curtis E. , Higa Kelvin T. , Tran Thao T. , Albro W. Rick
Published: February 2012

The objectives of this work are to characterize thermite initiation processes and thresholds, and to develop thermite reactive trains, where a sensitive nanothermite ignites an insensitive micron thermite, which produces little gas. Nanothermites, including Al/AgIO3, Al/Bi2O3, Al/MoO3, Al/Fe3O4, and Ti/AgIO3, were characterized for their ignition behavior by spark and resistive heating. Energies for spark and thermal initiation were as low as 9 and 140 μJ, respectively. Thermal initiation results were consistent with local temperature as the main controlling factor. The propagation rate of the Al/Fe3O4 nanothermite was about 100X slower than that of the other nanothermites. This low reactivity is attributed to the high volatilization temperature and high melting point of the oxidizer. Mixing of 90% Al/Fe3O4 nanothermite with 10% of a more sensitive, high-gas-producing nanothermite gave materials with the same sensitivity as the sensitive nanothermite. Thus, the mixture provides a safer sensitive nanothermite. Thermites with micron-scale ingredients were pressed into pellets and ignited with small amounts of nanothermite. Gas production of micron thermite compositions was reduced by adding the intermetallic composite, Ti/2B, or excess iron. In both cases, a single hot mass was produced, while the pure micron Al/Fe2O3 produced a dispersion of particles.
Surface Modification of Polycarbonateurethane by Grafting Phosphorylcholine Glyceraldehydes for Improving Hemocompatibility
Authors: Gao Wei , Feng Yakai , Lu Jian , Guo Jintang
Published: February 2012

Phosphorylcholine glyceraldehyde (PCGA) was used as a phosphorylcholine (PC) group containing compound to graft onto the surface of polycarbonateurethane (PCU) film using 1,6-hexanediamine (HDA) or α,ω-diamino-poly(ethylene glycol) (APEG, Mn = 200) as a spacer, in order to introduce biomimetic structure onto the polymer surface. X-ray photoelectron spectroscopy (XPS) analysis shows that PCGA has been covalently linked to the PCU surface. Water contact angle test suggests that the surface hydrophilicity has been improved after PCGA is grafted onto the surface of PCU film. Scanning electron microscope (SEM) observation of the modified PCU films after contacting with plasma-rich plasma demonstrates that platelets rarely adhere but a large number of platelets adhere to the original PCU surface. The hemocompatibility of the PC modified PCU film has been improved obviously after grafting with PCGA with PEG spacer.
Gelation Characteristics and Encapsulation of Stromal Cells in Star Acrylate-Functionalized Poly(ethylene glycol-co-lactide) Macromonomers
Authors: Moeinzadeh Seyedsina , Barati Danial , He Xuezhong , Jabbari Esmaiel
Published: February 2012

In this work, a novel star 4-arm poly(ethylene glycol-co-lactide) acrylate macromonomer (SPELA) is synthesized, and the effect of macromonomer concentration and architecture on modulus, swelling ratio and sol fraction is investigated. The results show that the storage modulus of the hydrogel had an increasing trend with polymer concentration. Changing the polymer architecture from linear to 4-arm increased the storage modulus by 2.2-fold. The water content depended on the hydrophilic segment density as well as the extent of crosslinking and showed a decreasing trend with macromonomer concentration. The sol fractions of the SPELA hydrogels changed from 13% to 5% when concentration increased from 10% to 25%. The star SPELA hydrogel with high modulus, fast gelation time, and low sol fraction is potential useful as a degradable carrier in cell-based therapies. Results show that the SPELA hydrogel supports viability and osteogenic differentiation of the encapsulated bone marrow stromal cells.
Optimization of Alloy-Coating Compositions for Use as Solid Oxide Fuel Cell Interconnects
Authors: Fergus Jeffrey W. , Zhao Yu , Liu Yingjia
Published: February 2012

Reduction in the operating temperature of solid oxide fuel cells (SOFCs) allows for the use of ferritic stainless steels as the interconnect material. However, cathode poisoning due to volatilization of chromium from the oxide scale formed on these alloys requires the use of a ceramic coating on the alloy. The reaction layer formed between the coating and the alloy affects the performance of the fuel cell, so the composition and properties of this layer must be considered in selecting the alloy and coating compositions. In this paper, the factors relevant to selection of the alloy/coating materials and the effect of the alloy-coating interaction on these factors are discussed.
Roles of boron in growth of diamond grains in ultrananocrystalline diamond/hydrogenated amorphous carbon composite films prepared by pulsed laser deposition
Authors: Ohmagari Shinya , Katamune Yūki , Ichinose Hikaru , Yoshitake Tsuyoshi
Published: February 2012

Boron doped ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon composite films prepared by pulsed laser deposition were structurally investigated. With an increase in the boron content, the grain size was increased from 5 to 23 nm accompanying by the lattice constant approaching to that of bulk diamond. The near-edge X-ray absorption fine-structure revealed that boron atoms are preferentially distributed into grain boundaries. On the basis of the results, the roles of the boron atoms in the enhanced crystalline growth are discussed. We consider that the crystalline growth posterior to the nucleation is facilitated by boron atoms existing neighbor to UNCD grains or by boron-containing energetic species in plasma.
Modeling of Early Stages of Formation of Poly-CO
Authors: Batyrev I. G. , Mattson W. D. , Rice B. M.
Published: February 2012

We studied the early stages of polymerization of CO under pressure. We performed DFT simulations of 128 and 432 atom models. Structures of random networks found at zero temperature were used for equilibration at 100 K by employing first principles MD. We found that the polymerization begins at 7 - 8 GPa and slightly depends on the size of the model. It turned out that there are several metastable phases of the extended CO solid, corresponding to different compression pressures from 7 - 8 GPa to 15-18 GPa with different numbers of CO fragments, not connected to the random network. We also found that the transition to the phases is irreversible which results in hysteresis loops. Random network structures obtained, say, under 18 GPa could exist at 3 GPa, whereas compression to 3 GPa results in the delta phase of CO crystal, with intact CO fragments and minor distortion of the cubic phase. To analyze the random structure fragments we calculated normal modes and IR intensities using the dipole approximation. Contributions from the main motifs of the random network are identified and compared with experimental IR measurements.
Gas Diffusion Media for Proton Exchange Membrane Fuel Cells Made from Carbon Fibers with Controlled Conductivity
Authors: Nicotera Paul , Evans Robert , Weaver Christopher , Abel Chuang Po-Ya
Published: February 2012

Samples of carbon fiber were prepared from polyacrylonitrile (PAN)-based precursors, covering a range of electrical resistivity from 0.9 to 1,000 mΩ cm corresponding to a range of carbonization heat treatment temperatures (HTT) estimated to be between 700 and 2600°C. Experimental gas diffusion media (GDM) were made from these fibers using conventional phenolic resin/carbon fiber construction, prepared at two different carbonization temperatures (950 and 2150°C). GDM thermal and electrical properties displayed similar trends with respect to fiber and paper HTT. Unexpectedly, GDM bending and shear moduli increased with fiber resistivity, possibly due to shortening of the lower resistivity fiber types during GDM production. Results showed that high HTT of either the carbon fiber or the paper was sufficient to enable average (“wet” and “dry”) 5-cm2 fuel cell performance comparable to current state-of-the-art GDM. A proprietary GDM wet-laid production model predicts a potential cost reduction of about 2% at 20 million m2 annual production by reducing the paper HTT.
AlN/GaN Distributed Bragg Reflectors Grown via Metal Organic Vapor Phase Epitaxy using GaN Insertion Layers
Authors: Rodak L. E. , Peacock J. , Justice J. , Korakakis D.
Published: February 2012

Distributed Bragg Reflectors (DBRs) are an important component of various optoelectronic devices for ultra violet and visible wavelengths. In the III-Nitride material system, Aluminum Nitride (AlN) and Gallium Nitride (GaN) offer a large contrast in refractive index and are therefore well suited for fabricating DBRs with high reflectivity and wide bandwidths using relatively few periods. However, the large lattice and thermal mismatch leads to cracking in these heterostructures. In this work short period superlattice layers have been used to fabricate high reflectivity (> 94%) nitride based DBRs via Metal Organic Vapor Phase Epitaxy. Short period AlN/GaN superlattices containing three to four monolayers of GaN have been employed as the low refractive index layer in DBRs to minimize cracking. Using this technique, crack-free DBRs reflecting from 440-475 nm with up to 25 periods have been fabricated. The technique has been proven to be versatile and resulted in large area yield DBRs grown on a variety of different sapphire substrates.
Molecular Beam Epitaxial Growth of Nonpolar a-plane InN/ GaN Heterostructures
Authors: Rajpalke Mohana K. , Bhat Thirumaleshwara N. , Roul Basanta , Kumar Mahesh , Krupanidhi S. B.
Published: February 2012

Nonpolar a-plane InN/GaN heterostructures were grown by plasma assisted molecular beam epitaxy. The growth of nonpolar a- plane InN / GaN heterostructures were confirmed by high resolution x-ray diffraction study. Reflection high energy electron diffraction patterns show the reasonably smooth surface of a-plane GaN and island-like growth for nonpolar a-plane InN film, which is further confirmed by scanning electron micrographs. An absorption edge in the optical spectra has the energy of 0.74 eV, showing blueshifts from the fundamental band gap of 0.7 eV. The rectifying behavior of the I-V curve indicates the existence of Schottky barrier at the InN and GaN interface. The Schottky barrier height (φb) and the ideality factor (η) for the InN/GaN heterostructures found to be 0.58 eV and 2.05 respectively.
Structures of Bromoinated Oligothiophenes and Ethylenedioxythiophenes: A Combined Experimental and Theoretical Study
Authors: Bader Mamoun M. , Pham Phuong-Truc T.
Published: February 2012

In this work, we report the results of solid state structural study of a series of oligothiophenes and ethylenedioxythiophenes (EDOT) endowed with bromine atoms at different positions and in the presence/absence of the strong electron acceptor, the tricyanovinyl group (TCV). Five new compounds were synthesized, crystallized and their single crystal structures were determined by X-ray diffraction. The impact of bromine atom(s) on solid state packing as viewed through analysis of intermolecular interactions is presented. Comparative study using experimental, computed and published data of closely related structures shows intra-molecular interactions involving Br in the presence of TCV and EDOT. Distances shorter that the summation of the Van der Waals radii were observed which indicate the role of Br…NC, S…S and Br…Br interactions in addition to pi stack formation and planarity of these compounds due to the presence of strong electron acceptors. Possible implications of how these structural features may impact charge transport in oligothiophenes will be discussed.
Manufacturing of Fibres with New Reflective Properties and their Application in Textiles
Authors: Picot Olivier T. , Dai Mian , Peijs Ton , Bastiaansen Cees W.M.
Published: February 2012

Reflective fibres were obtained in a two step process. First a core polyamide 6 fibre was spun from the melt and successively stretched. Then a chiral nematic liquid crystal coating was applied onto the surface of this fibre and further cured under UV light. The liquid crystal alignment was controlled by the molecular orientation of the polymer fibre and the 10 μm thick mono-domain coating presented a periodic helical organisation with a pitch of 350 nm. The obtained fibre showed strong Bragg reflection giving an intense green colour changing upon viewing angle. The fibre has been integrated into a fabric suggesting its application for textile design, fashion, and apparel.
Phase Transition Behavior of Main Chain Nematic Liquid-Crystalline Polymers Based on 2-methyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone and 2-tert-butyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone
Authors: Melchert Christain , Behl M. , Lendlein A.
Published: February 2012

The control of phase transition behavior in liquid crystalline polymers could enable potential application in the field of actuators and sensors by enabling a higher actuator performance of liquid crystalline elastomers (LCE). In this context the phase transition behavior of siloxane based liquid crystalline copolymers synthesized from 1,1,3,3-tetramethyldisiloxane, 2-methyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone (M-MeHq), and 2-tert-butyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone (M-tBHq) was explored. The selected monomers provided different thermal stabilities of the nematic phase, while the non-flexible siloxane spacer suppressed a smectic phase. The mesogenic properties were studied by means of differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and wide angle X-ray scattering (WAXS). With increasing fraction of M-MeHq the nematic phase of the copolymer was stabilized and a tailoring of relatively low TNI was achieved.
Lower and middle Cambrian rhynchonelliform brachiopods from the Precordillera terrane of Argentina
Authors: Benedetto Juan L. , Foglia Rodolfo D.
Published: February 2012

The first Cambrian rhynchonelliformean brachiopods are described from the Precordillera mountain belt of west-central Argentina, including the new species Wimanella mollensis and Nisusia ancauchensis. Other forms are Diraphora cf. D. borealis (Walcott), Diraphora sp., and an indeterminate bohemiellid. Brachiopods come from the lowermost part of the Precordilleran Cambrian succession (El Estero and Soldano Members of the La Laja Formation, Cerro Totora Formation) and from the Ancaucha olistolith within the Los Sombreros olistostrome. The associated trilobites constrain the fossiliferous levels to the Bonnia-Olenellus, Poliella denticulata and Ehmaniella biozones. A re-assessment of paleobiogeographic affinities of lower and early middle Cambrian rhynchonelliform brachiopods using cluster analysis supports the existence of a widespread warm-water Tropical Realm—to which the described Precordilleran faunas belong—and a more restricted ‘Mediterranean’ Realm developed on the temperate, mixed clastic-carbonate platforms.
Coral-crinoid biocoenosis and resulting trace fossils from the Middle Devonian of the Eifel Synclines (Rhenish Massif, Germany)
Authors: Bohatý Jan , Ausich William I. , Nardin Elise , Nyhuis Christian , Schröder Stefan
Published: February 2012

Fossil echinoderms are a rich source of information concerning biotic interactions. In this study we analyzed the premortem encrustation of the highly specialized Middle Devonian rugose coralsAspasmophyllum crinophilumand ?“Adradosia” sp. on camerate crinoid stems.Aspasmophylluminfested living crinoid stems by sclerenchymal outgrowth that formed a skeletal ring but ?“Adradosia” sp. encrusted the stems rapidly, without building a ring. These coral-crinoid biocoenoses indicate a settlement advantage for the rugose corals within densely populated communities of the lower Givetian. The corals could be interpreted as large epizoozoans that benefited as secondary tierers reaching relatively high tiering levels. It also suggests the ability for the affected crinoids to repel the coral by overgrowing the corallite with a local increased stereomic growth. Because the crinoid axial canals are not penetrated, the corals cannot be considered as predators or parasites of crinoids. Therefore, the described biocoenosis is interpreted as commensalism. The speciesA. crinophilumis redescribed, and a neotype is defined, because of the loss of the initial types. Two types of ichnofossils can be attributed to the premortem encrustation of both corals. They are described asOstiocavichnusn. ichnogen. and are attributed to the stereomic response of the infested hosts. These swellings are characterized as either elliptical (Ostiocavichnus ovalisn. ichnogen. n. ichnosp. due to the assumed reaction ofA. crinophilum) or subcircular concavities (O. rotundatusn. ichnogen. n. ichnosp. due to the reaction of ?“Adradosiasp.”).
Variable growth modes in Late Cretaceous ammonoids: implications for diverse early life histories
Authors: Arai Kazato , Wani Ryoji
Published: February 2012

Examination of ontogenetic changes in the septal angle of Late Cretaceous ammonoids (ten species representing seven superfamilies and four suborders) reveals four patterns: 1) a single abrupt change in septal angle; 2) two abrupt changes in septal angle; 3) cyclic fluctuations in septal angle throughout ontogeny; and 4) an almost constant septal angle throughout ontogeny. These various septal-angle patterns in Late Cretaceous ammonoids are in contrast with modern and fossil nautiloids, which have the common pattern displaying a single abrupt change in septal angles. Although the abrupt change of septal angles in nautiloids corresponds with the hatching event from the egg, change of septal angles in the examined ammonoids is hypothesized to correspond not to hatching but to the change from a planktic to a nektobenthic habit demarcated by the post-embryonic stage. Therefore, the variable patterns of septal angles within ammonoids suggest a diverse set of early life histories.
The Family Cancellariidae (Mollusca: Gastropoda) in the Neogene of the Bocas Del Toro Region, Panama, with the description of seven new species
Authors: Landau Bernard , Petit Richard E. , Da Silva Carlos M.
Published: February 2012

Twenty four species of Cancellariidae belonging to eleven genera occurring in the Neogene Bocas del Toro assemblages, Caribbean Panama, are discussed and figured. The following seven species are described as new:Cancellaria pilulan. sp.,Cancellaria isabelaen. sp.,Cancellaria strin. sp.,Cancellaria axelolssonin. sp.,Massyla corpulentan. sp.,Aphera trophisn. sp.,Admetula valientensisn. sp. The cancellarid genusCharcolleriaOlsson, 1942 is considered a synonym ofMassylaH. Adams and A. Adams, 1854. Of the 24 species present in the Bocas del Toro, 12 are known also to occur elsewhere in the tropical American Neogene. This level of endemism is high, but not as high as that reported from other Tropical American Neogene assemblages, probably due to the very central geographic location within the Gatunian Province of the Bocas assemblages.
Diverse new microvertebrate assemblage from the Upper Triassic Cumnock Formation, Sanford Subbasin, North Carolina, USA
Authors: Heckert Andrew B. , Mitchell Jonathan S. , Schneider Vincent P. , Olsen Paul E.
Published: February 2012

The Moncure microvertebrate locality in the Cumnock Formation, Sanford sub-basin, North Carolina, dramatically increases the known Late Triassic age vertebrate assemblage from the Deep River Basin. The ∼50,000 recovered microvertebrate fossils include osteichthyans, amphibians, and numerous lepidosauromorph, archosauriform, and synapsid amniotes. Actinopterygian fossils consist of thousands of scales, teeth, skull, and lower jaw fragments, principally of redfieldiids and semionotids. Non-tetrapod sarcopterygians include the dipnoanArganodussp., the first record of lungfish in the Newark Supergroup. Temnospondyls are comparatively rare but the preserved centra, teeth, and skull fragments probably represent small (juvenile) metoposaurids. Two fragmentary teeth are assigned to the unusual reptileColognathus obscurus(Case). Poorly preserved but intriguing records include acrodont and pleurodont jaw fragments tentatively assigned to lepidosaurs. Among the archosauriform teeth is a taxon distinct fromR. callenderithat we assign toRevueltosaurus olseninew combination, a morphotype best assigned to cf.Galtonia, the first Newark Supergroup record ofCrosbysaurussp., and several other archosauriform tooth morphotypes, as well as grooved teeth assigned to the recently named speciesUatchitodon schneideri. Synapsids represented by molariform teeth include both “traversodontids” assigned to aff.Boreogomphodonand the “dromatheriid”Microconodon. These records are biogeographically important, with many new records for the Cumnock Formation and/or the Newark Supergroup. In particular,Colognathus,Crosbysaurus, andUatchitodonare known from basins of Adamanian age in the southwestern U.S.A. These new records include microvertebrate taxa more typical of non-Newark basins (abundant archosauriforms, temnospondyls, lungfish) as well as more typical Newark osteichthyans and synapsid-rich faunal elements.
Fluid simulation: combined Lagrangian and multi-grid approach
Authors: Ophir Dan , Yahalom Asher , Pinhasi Gad A. , Kopylenko Michael
Published: February 2012

This paper proposes a new approach for solving partial differential equations related to fluid problems. The technique merges two methods: the variational numerical method and the multi-grid technique. The modified variational numerical method with a grid refinement module is used to solve physical equations by finding the action minimum on a coarse grid and interpolating it to finer grids, with reduced computer work on the finer grid while achieving the same accuracy. The interpolation computer work can be performed efficiently and therefore may be neglected compared with the time invested in the variation solution itself. The current work analyses the effect of algorithm parameters such as the number of levels, the required accuracy and the type of grid point.
Liquefied natural gas tank analysis: cryogenic temperatures and seismic loading
Authors: Gillard Marcus N. T. , Leslie Mathew J. , Vaughan David J. , Spencer William A.
Published: February 2012

This paper describes several of the advanced non-linear finite-element analyses required for the design of a full containment 155 000 m3 liquefied natural gas (LNG) tank. The focus is on the analysis of the prestressed concrete outer containment, which resists the loading of cryogenic liquid in the case of inner tank failure. Accurate modelling of the effects of −164°C LNG on a concrete tank is in itself a significant non-linear task. Of critical importance are the stresses and cracking induced in the wall by the evolution of a cold front. A transient analysis is presented that ensures the tank remains liquid-tight. The tank is also required to remain liquid-tight in a seismic event, which in this case follows inner tank failure. A transient dynamic analysis of earthquake loading on a tank containing the cryogenic liquid is also presented. The work, carried out using Diana and Ansys, fully confirms the adequacy of the design.
Seasonal patterns in immune indices reflect microbial loads on birds but not microbes in the wider environment
Authors: Horrocks Nicholas P. C. , Matson Kevin D. , Shobrak Mohammed , Tinbergen Joost M. , Tieleman B. Irene
Published: February 2012

Documenting patterns in immune function is a first step to understanding immune variation, but to comprehend causes and consequences, antigen and parasite exposure that may drive such variation must be determined. We measured host‐independent microbial exposure in five species of larks (Alaudidae) in the Arabian Desert by sampling ambient air for culturable microbes during late spring and winter, two periods with contrasting environmental conditions. We developed a novel technique to assay densities of microbes shed from birds, and we quantified four indices of constitutive innate immunity. Birds shed significantly more microbes during spring than winter, and all immune indices except one were also significantly higher during spring. In contrast, concentrations of airborne environmental microbes were higher in winter. Among all birds in both seasons, lysis titers were positively correlated with total densities of microbes shed from birds, suggesting that immune defenses are directed towards the microbes that birds carry, rather than microbes in the wider environment. Our findings highlight the relevance of quantifying non‐specific immune challenges in ecological immunology studies, and reinforce the importance of both host‐dependent and host‐independent measures of antigenic pressure for understanding immune variation.
Evaluation of Human Recession Defects Treated With Coronally Advanced Flaps and Either Enamel Matrix Derivative or Connective Tissue: Comparison of Clinical Parameters at 10 Years
Authors: McGuire Michael K. , Scheyer E. Todd , Nunn Martha
Published: February 2012

Background: The effective treatment of gingival recession (GR) defects is crucial for predictable outcomes. The most common treatment is the subepithelial connective tissue graft (CTG), but good outcomes have also been obtained using enamel matrix derivative (EMD). A split‐mouth, randomized controlled trial was previously performed during a 12‐month period to evaluate primary and secondary outcomes in Miller Class I and II GR defects treated with CTG or EMD, both in combination with coronally advanced flap (CAF). The purpose of the current study is to examine the major qualitative and quantitative parameters of this study after a 10‐year follow‐up.

Methods: Nine of 17 original patients were available for follow‐up evaluation 10 years after the original surgery. The parameters measured were: 1) GR depth; 2) probing depth (PD); 3) clinical attachment level; 4) width of keratinized tissue (wKT); 5) percentage of root coverage; 6) root dentin hypersensitivity; 7) color, texture, and contour of treatment sites; and 8) patient satisfaction at 10 years. Results at 1 and 10 years of these nine patients (nine test and nine control teeth) were compared to original baseline values. In addition, results within treatment groups between 1 and 10 years and between treatment groups (i.e., EMD versus CTG) at the same time points were examined.

Results: At 10 years, all quantitative parameters except PD for both treatment protocols showed statistically significant improvements from baseline values, including wKT in the EMD group, which at 1 year was not significantly improved compared with baseline wKT. In addition, at 10 years, there were no statistically significant differences between EMD + CAF and CTG + CAF for any measured parameter. The only statistically significant finding in this study was the difference in wKT found at 1 year (EMD, 3.00 mm; CTG, 3.89 mm; P = 0.031). Qualitative parameters at 10 years demonstrated similar stability. The only major qualitative difference was the marginal tissue contour, which was similar to adjacent tissues at EMD‐treated sites but greater than adjacent tissues at all CTG sites except one. Esthetically, both EMD‐ and CTG‐mediated treatments were similar at 10 years. However, given the choice, six of nine patients would choose EMD over CTG treatment to avoid a secondary harvesting procedure.

Conclusions: This paper highlights the importance of long‐term data as it relates to procedural effectiveness in selecting optimally effective protocols to treat gingival recession. Based on the results of this 10‐year follow‐up investigation, treatment with either EMD + CAF or CTG + CAF for Miller Class I and II GR defects appears stable, clinically effective, and similar to each other on all measured parameters.
Comparative Evaluation of Autologous Platelet‐Rich Fibrin and Platelet‐Rich Plasma in the Treatment of 3‐Wall Intrabony Defects in Chronic Periodontitis: A Randomized Controlled Clinical Trial
Authors: Pradeep A.R. , Rao Nishanth S. , Agarwal Esha , Bajaj Pavan , Kumari Minal , Naik Savitha B
Published: February 2012

Background: The topical use of platelet concentrates is recent, and its efficiency remains controversial. The present study aims to explore the clinical and radiographic effectiveness of autologous platelet‐rich fibrin (PRF) and platelet‐rich plasma (PRP) in the treatment of intrabony defects in patients with chronic periodontitis.

Methods: Ninety intrabony defects were treated with either autologous PRF with open‐flap debridement or autologous PRP with open‐flap debridement or open‐flap debridement alone. Clinical and radiologic parameters, such as probing depth (PD), clinical attachment level (CAL), intrabony defect depth, and percentage defect fill, were recorded at baseline and 9 months postoperatively.

Results: Mean PD reduction and CAL gain were greater in PRF (3.77 ± 1.19 and 3.17 ± 1.29 mm) and PRP (3.77 ± 1.07 and 2.93 ± 1.08 mm) groups than the control group (2.97 ± 0.93 and 2.83 ± 0.91 mm). Furthermore, significantly greater percentage of mean bone fill was found in the PRF (55.41% ± 11.39%) and PRP (56.85% ± 14.01%) groups compared with the control (1.56% ± 15.12%) group.

Conclusions: Within the limit of the present study, there was similar PD reduction, CAL gain, and bone fill at sites treated with PRF or PRP with conventional open‐flap debridement. Because PRF is less time consuming and less technique sensitive, it may seem a better treatment option than PRP. However, long‐term, multicenter randomized, controlled clinical trials will be required to know their clinical and radiographic effects on bone regeneration.
Teachers Changing Worlds
Authors: Quin Jane
Published: February 2012

Even big waves of political revolution are not able to wash away deeply internalised oppression and entrenched injustice – especially far away from the epicentre where only the ripples reach. Deep in South African rural schools, steeped in layers of social and cultural oppression that has shape-shifted through generations of political regimes, are scatterings of teachers taking on the frequently lonely task of teaching for social justice. It is precisely their contextual knowledge of the nuances of the power play of the hegemonic norms that makes possible their ways of working. Through a structured pedagogical journey of critical consciousness-raising, this article reports on the conduct and outcomes of self-reflective action research to facilitate more socially just practices in the writers' own schools, presenting some of the self-reflective action research reports/stories of these educators produced while they work for social justice.
Sacajawea: Witnessing, Remembrance and Ignorance
Authors: Pillow Wanda S.
Published: February 2012

This article considers the relations between discourse, knowledge, power and representations, and particularly how constructs and ideologies of gender, race and sexuality impact what we think we know, how we come to know it, and where this knowledge goes in theory, policy and practice. The story of Sacajawea, a Lemhi-Shoshone woman who was involved in the 1804–06 US Corp of Discovery expedition, is used as an examplar of how hegemonic representations, passed on through curriculum content, can distort understandings and perpetuate colonial and othering perspectives.
Imagining a World Where Paris Hilton Loves Mathematics
Authors: Vakharia Vanessa
Published: February 2012

This article is a conceptual piece which explores what it might be like to incorporate marketing theory and notions of cool into the realm of mathematics education in an attempt to elicit mathematical enthusiasm from a specific subset of the female population who often self-select out of mathematics despite their high mathematical aptitude. Focusing on girls from Toronto, Canada, who generally see themselves as part of the mainstream culture, this article speculates as to how these girls understand their relationship to mathematics. The central purpose of this research is to understand whether these girls choose not to pursue mathematics beyond the compulsory level because they are selecting courses to construct their identity on the basis of cool, using the same evaluation process they would when selecting products. Drawing extensively on literature and participant data, this article presents a novel perspective with which to view female disinterest in mathematics. Grounding the empirical data atop the theoretical brings to life the interconnection of perspectives of scholars like Walkerdine, Mendick, Demetriou and Gladwell, illustrating how femininity, consumerism and mathematics are interwoven into the very fabric of our socially constructed reality. This article argues that treating mathematics as a consumer good and marketing it accordingly might give rise to increased mathematical participation and enthusiasm by this particular segment of girls, who rely on identity marketing for many of their consumption decisions.
Locally finite groups with all subgroups either subnormal or nilpotent-by-Chernikov
Authors: Cutolo Giovanni , Smith Howard
Published: February 2012

Let G be a locally finite group satisfying the condition given in the title and suppose that G is not nilpotent-by-Chernikov. It is shown that G has a section S that is not nilpotent-by-Chernikov, where S is either a p-group or a semi-direct product of the additive group A of a locally finite field F by a subgroup K of the multiplicative group of F, where K acts by multiplication on A and generates F as a ring. Non-(nilpotent-by-Chernikov) extensions of this latter kind exist and are described in detail.
Differential geometry of grassmannians and the Plücker map
Authors: Anan’in Sasha , Grossi Carlos
Published: February 2012

Using the Plücker map between grassmannians, we study basic aspects of classic grassmannian geometries. For ‘hyperbolic’ grassmannian geometries, we prove some facts (for instance, that the Plücker map is a minimal isometric embedding) that were previously known in the ‘elliptic’ case.
Vaaisible upconversion emission of Er3+-doped and Er3+/Yb3+-codoped LiInO2
Authors: Djačanin Ljubica , Dramićanin Miroslav , Lukić-Petrović Svetlana , Petrović Dragoslav , Nikolić Marko
Published: February 2012

Lithium-indium oxide is a high-density (5.9 g·cm−3), wide band-gap semiconductor with promising applications for scintillating detection of solar neutrinos as well as for efficient phosphorescence when doped with Er3+ or Sm3+ ions. In this report, we demonstrate visible upconversion emission of Er3+-doped LiInO2 synthesized by a simple solid-state chemistry procedure and discuss mechanisms responsible for pumping the Er3+ ions to upper levels. Intense upconversion emission is observed in the green and red spectral regions under near-infrared excitation, and it is greatly enhanced by co-doping with Yb3+ ions. We also examined the upconversion intensity change as a function of temperature, and, consequently, possible applications of this material as a low-temperature sensor.
Synthesis, anti-oxidant activity, and cytotoxicity of salicyloyl derivatives of estra-1,3,5(10)-triene and androst-5-ene
Authors: Gaši Katarina , Djurendić Evgenija , Dojčinović-Vujašković Sanja , Gaković Andrea , Jovanović-Šanta Suzana , Kojić Vesna , Sakač Marija
Published: February 2012

Since many estrane and androstane derivatives exhibit cytotoxic, anti-oxidant, or anti-hormone activity, new steroidal derivatives were synthesised from appropriate estrogen or androgen precursors in order to obtain potential therapeutics for the treatment of steroid-dependent diseases. Starting from estradiol (I), 6-oxo derivatives V and VII were prepared. 17β-Salicyloyl-6-oxo derivatives VI and VIII were synthesised by the reaction of compounds V or VII with methyl salicylate in the presence of sodium. 17β-Salicyloyloxy estradiol IX was prepared from estradiol. Beckmann fragmentation of 16-oxyimino alcohols XII and XIII with methyl salicylate yielded corresponding D-seco derivatives XIV and XV. Simultaneous fragmentation and acylation of compound XII resulted in 3β-salicyloyl-D-seco derivative XVI which was also obtained from compound XIV. Anti-oxidant assays of the newly synthesised compounds V-IX, XIV, and XVI indicated a stronger capacity for hydroxyl radical scavenging, and a weaker capacity for DPPH radical scavenging, compared with the standard anti-oxidants BHA and BHT. Compounds V, XIV, and XVI showed higher or the same activity as BHT. The cytotoxicity of new compounds was evaluated against human breast and prostate carcinoma cells. Compound VI exhibited strong cytotoxicity against MDA-MB-231 cells; compound XIV exhibited strong cytotoxicity against PC-3 cell line, while compound VII moderately inhibited the growth of PC-3 cells.
Photodynamic efficiency of porphyrins encapsulated in polysilsesquioxanes
Authors: Rychtáriková Renata , Šabata Stanislav , Hetflejš Jiří , Kuncová Gabriela
Published: February 2012

Mesoporous organosilica-porphyrin composites were obtained by entrapment of 5,10,15,20-tetraphenylporphyrin (TPP) and 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin (TMPyP) into three polysilsesquioxanes prepared by the sol-gel method from 1,2-bis(triethoxysilyl)ethane, 1,6-bis(triethoxysilyl)hexane, and 1,8-bis(triethoxysilyl)octane. The materials were characterised by their texture and optical properties (fluorescence and absorbance) and by light-induced antimicrobial activity against E. coli BL21(DE3) (pET16bDsRed) strain.
Utilisation of industrial waste for ferrite pigments production
Authors: Schwarz Marián , Veverka Miloš , Michalková Eva , Lalík Vladimír , Veverková Darina
Published: February 2012

Preliminary results of research focused on the utilisation of specific waste from metallurgical and mining activities to obtain ferrite pigments are presented. As a source of iron in the spinel-type ferrites with the general structure MFe2O4 (where M is a bivalent metal such as Ca and Zn), three types of industrial wastes were used: metallurgical slag from the production of non-ferrous metals and two types of AMD (acid mine drainage) sludge: one of natural origin (Fe-sediment) and the second one synthetically prepared from AMD (Fe-precipitate). This waste was homogenised by ZnO and CaCO3 in various stoichiometric ratios n(Ca): n(Zn): n(Fe) and calcined at the temperature of 1000–1095°C. Mineralogical (XRD) analysis of the metallurgical slag pigments confirmed the formation of zinc ferrite and hematite only (Ca from reaction components entered into other phases). The ferric component of the AMD sludge (Fe-precipitate and Fe-sediment) formed a mixture of zinc ferrite, calcium ferrite, and hematite while increased calcination temperature supported the ferritic structure formation. Prepared pigments have no considerable colour differences; they were in brown colour tones. Pigments from the AMD sludge were more dark brown coloured than those from slag. Pigments were applied in an alkyd-resin paint and consequently basic anticorrosive tests were performed. Pigments obtained from metallurgical slag showed better anticorrosive properties than those from AMD. However, because of high Pb content in pigments from the slag (0.67–1.10 mass % Pb in pigments), utilisation of these pigments in coatings is problematic. Ferrite pigments from the AMD sludge, mainly that with zinc ferrite, have promising application in anticorrosive paints but optimisation of the preparation process is required.
Investigating the use of terahertz pulsed time domain reflection imaging for the study of fabric layers of an Egyptian mummy
Authors: Fukunaga Kaori , Cortes Emilia , Cosentino Antonino , Stünkel Isabel , Leona Marco , Duling Irl N. , Mininberg David T.
Published: February 2012

This paper reports the first use of terahertz time domain reflection imaging involving textiles on part of a complete human mummy, still in original wrapping. X-ray technique has been used extensively to investigate anatomical features, since X-ray pass through the wrapping. Terahertz waves, on the other hand, can penetrate into non-metallic materials and its reflection depends on the refractive index of materials at the interface, such as textiles and the air. The mummy of Kharushere (ca. 945-712 B.C.) was examined by using Terahertz time domain reflection imaging in the Egyptian galleries of The Metropolitan Museum of Art. Experimental results suggest that the Terahetz imaging is a promising technique for probing the fabric layers surrounding Egyptian mummies, although it is still very limited in its current state. In the future it could become a useful complement to CT scanning when materials with low radiographic density and contrast are being investigated.
Neuronal chemotaxis by optically manipulated liposomes
Authors: Pinato G. , Lien L. T. , D’Este E. , Torre V. , Cojoc D.
Published: February 2012

We probe chemotaxis of single neurons, induced by signalling molecules which were optically delivered from liposomes in the neighbour-hood of the cells. We implemented an optical tweezers setup combined with a micro-dissection system on an inverted microscope platform. Molecules of Netrin-1 protein were encapsulated into micron-sized liposomes and manipulated to micrometric distances from a specific growth cone of a hippocampal neuron by the IR optical tweezers. The molecules were then released by breaking the liposomes with UV laser pulses. Chemotaxis induced by the delivered molecules was confirmed by the migration of the growth cone toward the liposome position. Since the delivery can be manipulated with high temporal and spatial resolution and the number of molecules released can be controlled quite precisely by tuning the liposome size and the solution concentration, this technique opens new opportunities to investigate the effect of physiological active compounds as Netrin-1 to neuronal signalling and guidance, which represents an important issue in neurobiology.
Self calibration of sensorless adaptive optical microscopes
Authors: Thayil Anisha , Booth Martin J.
Published: February 2012

We present a self-calibrating scheme for microscopes using model-based wavefront sensorless adaptive optics. Unlike previous methods, this scheme permits the calibration of system aberration modes without the need for a separate wavefront sensor or interferometer. Basis modes are derived from the deformable mirror influence functions and an image cross-correlation method is used to remove image displacement effects from these modes. Image based measurements are used to derive an optimum modal representation from the displacement-free basis modes. These new modes are insensitive to system misalignments and the shape of the illumination profile. We demonstrate the effectiveness and robustness of these optimal modes in a third harmonic generation (THG) microscope.