bluuebunny/crossref_metadata_2025 huggingface dataset:
Size-resolved measurements of brown carbon and estimates of their contribution to ambient fine particle light absorption based on water and methanol extracts
Authors: Liu J. , Bergin M. , Guo H. , King L. , Kotra N. , Edgerton E. , Weber R. J.
Published: July 2013

Abstract. Light absorbing organic carbon, often termed brown carbon, has the potential to significantly contribute to the visible light absorption budget, particularly at shorter wavelengths. Currently, the relative contributions of particulate brown carbon to light absorption, as well as the sources of brown carbon are poorly understood. With this in mind field measurements were made at both urban (Atlanta), and rural (Yorkville) sites in Georgia. Measurements in Atlanta were made at both a central site and a road side site adjacent to a main highway near the city center. Fine particle brown carbon optical absorption is estimated based on Mie calculations using direct size resolved measurements of chromophores in filter extracts. Size-resolved atmospheric aerosol samples were collected using a cascade impactor and analyzed for water-soluble organic carbon (WSOC), organic and elemental carbon (OC and EC), and solution light absorption spectra of water and methanol extracts. Methanol extracts were more light-absorbing than water extracts for all size ranges and wavelengths. Absorption refractive indices of the organic extracts were calculated from solution measurements for a range of wavelengths and used with Mie theory to predict the light absorption by fine particles comprised of these components, under the assumption that brown carbon and other aerosol components were externally mixed. For all three sites, chromophores were predominately in the accumulation mode with an aerodynamic mean diameter of 0.5 μm, an optically effective size range resulting in predicted particle light absorption being a factor of 2 higher than bulk solution absorption. Fine particle absorption was also measured with a Multi-Angle Absorption Photometer (MAAP) and seven-wavelength Aethalometer. Scattering-corrected aethalometer and MAAP absorption were in good agreement at 670 nm and Mie-estimated absorption based on size-resolved EC data were within 30% of these optical instruments. When applied to solution measurements, at all sites, Mie-predicted brown carbon absorption at 350 nm contributed a significant fraction (20 to 40%) relative to total light absorption, with highest contributions at the rural site where organic to elemental carbon ratios were highest. Brown carbon absorption, however, was highest by the roadside site due to vehicle emissions. The multi-wavelength aethalometer did not detect brown carbon, having an absorption Ångstrom exponent near one. Although the results are within the estimated Aethalometer uncertainties, the direct measurement of brown carbon in solution definitively shows that it is present and this Mie analysis suggests it is optically important in the near UV range in both a rural and urban environment during summer when biomass burning emissions are low.
On the electron temperature downstream of the solar wind termination shock
Authors: Chashei I. V. , Fahr H. J.
Published: July 2013

Abstract. In this paper we study the temperatures of electrons convected with the solar wind to large solar distances and finally transported over the solar wind termination shock. Nearly nothing, unless at high energies in the cosmic ray regime, is known about the thermodynamical behaviour of these distant electrons from in~situ plasma observations. Hence it is tacitly assumed these electrons, due to their adiabatic behaviour and vanishing heat conduction or energization processes, have rapidly cooled off to very low temperatures once they eventually arrive at the solar wind termination shock (at about 100 AU). In this paper we show that such electrons, however, at their passage over the termination shock due to the shock–electric field action undergo an over-adiabatic heating and therefore appear on the downstream side as a substantially heated plasma species. Looking quantitatively into this heating process we find that solar wind electrons achieve temperatures of the order of 2–4 × 106 K downstream of the termination shock, depending on the upstream solar wind bulk velocity and the shock compression ratio. Hence these electrons therewith play an important dynamical role in structuring this shock and determining the downstream plasma flow properties. Furthermore, they present an additional ionization source for incoming neutral interstellar hydrogen and excite X-ray emission. They also behave similar to cosmic ray electrons and extend to some limited region upstream of the shock of the order of 0.1 AU by spatial diffusion and thereby also modify the upstream solar wind properties.
High greenhouse gas fluxes from grassland on histic gleysol along soil carbon and drainage gradients
Authors: Leiber-Sauheitl K. , Fuß R. , Voigt C. , Freibauer A.
Published: July 2013

Abstract. Drained organic soils are anthropogenic emission hotspots of greenhouse gases (GHGs). Most studies have focused on deep peat soils and on peats with high organic carbon content. In contrast, Histic gleysols are characterized by shallow peat layers, which are left over from peat cutting activities, or by peat mixed with mineral soil. It is unknown whether they emit less GHGs than deep Histosols when drained. We present the annual carbon and GHG balance of grasslands for six sites on nutrient-poor histic gleysols with a shallow (30 cm) histic horizon or mixed with mineral soil in Northern Germany (soil organic carbon concentration (Corg) from 9 to 52%). The net GHG balance, corrected for carbon export by harvest, was around 4 t CO2-C-eq. ha−1 yr−1 on soils with peat layer and little drainage (mean annual water table <20 cm below surface). The net GHG balance reached 7–9 t CO2-C-eq. ha−1 yr−1 on soils with peat layer and deeper drainage (mean annual water table >20 cm below surface) and on soils with sand mixed into the histic horizon, independent of water table level. GHG emissions from drained histic gleysols (i) were as high as those from deep histosols, (ii) linearly related to water table, (iii) but not affected by Corg content of the histic horizon. Ecosystem respiration (Reco) was linearly correlated with water table level even if it was below the histic horizon. The Reco : GPP ratio was 1.5 at all sites, so that we ruled out a major influence of the inter-site variability in vegetation composition on annual net ecosystem exchange (NEE). The IPCC definition of organic soils includes shallow histic topsoil, unlike most national and international definitions of histosols. Our study confirms that this broader definition is appropriate considering anthropogenic GHG emissions from drained organic soils. Countries currently apply soil maps in national GHG inventories which are likely not to include histic gleysols. The land area with GHG emission hotspots due to drainage is likely to be much higher than anticipated. Deeply drained histic gleysols are GHG hotspots which have so far been neglected or underestimated. Peat mixing with sand does not mitigate GHG emissions. Our study implies that rewetting organic soils, including histic gleysols, has a much higher relevance for GHG mitigation strategies than currently recognized.
Improving soil moisture profile reconstruction from ground-penetrating radar data: a maximum likelihood ensemble filter approach
Authors: Tran A. P. , Vanclooster M. , Lambot S.
Published: July 2013

Abstract. The vertical profile of shallow unsaturated zone soil moisture plays a key role in many hydro-meteorological and agricultural applications. We propose a closed-loop data assimilation procedure based on the maximum likelihood ensemble filter algorithm to update the vertical soil moisture profile from time-lapse ground-penetrating radar (GPR) data. A hydrodynamic model is used to propagate the system state in time and a radar electromagnetic model and petrophysical relationships to link the state variable with the observation data, which enables us to directly assimilate the GPR data. Instead of using the surface soil moisture only, the approach allows to use the information of the whole soil moisture profile for the assimilation. We validated our approach through a synthetic study. We constructed a synthetic soil column with a depth of 80 cm and analyzed the effects of the soil type on the data assimilation by considering 3 soil types, namely, loamy sand, silt and clay. The assimilation of GPR data was performed to solve the problem of unknown initial conditions. The numerical soil moisture profiles generated by the Hydrus-1D model were used by the GPR model to produce the "observed" GPR data. The results show that the soil moisture profile obtained by assimilating the GPR data is much better than that of an open-loop forecast. Compared to the loamy sand and silt, the updated soil moisture profile of the clay soil converges to the true state much more slowly. Decreasing the update interval from 60 down to 10 h only slightly improves the effectiveness of the GPR data assimilation for the loamy sand but significantly for the clay soil. The proposed approach appears to be promising to improve real-time prediction of the soil moisture profiles as well as to provide effective estimates of the unsaturated hydraulic properties at the field scale from time-lapse GPR measurements.
Climate change impacts on maritime mountain snowpack in the Oregon Cascades
Authors: Sproles E. A. , Nolin A. W. , Rittger K. , Painter T. H.
Published: July 2013

Abstract. This study investigates the effect of projected temperature increases on maritime mountain snowpack in the McKenzie River Basin (MRB; 3041 km2) in the Cascades Mountains of Oregon, USA. We simulated the spatial distribution of snow water equivalent (SWE) in the MRB for the period of 1989–2009 with SnowModel, a spatially-distributed, process-based model (Liston and Elder, 2006b). Simulations were evaluated using point-based measurements of SWE, precipitation, and temperature that showed Nash-Sutcliffe Efficiency coefficients of 0.83, 0.97, and 0.80, respectively. Spatial accuracy was shown to be 82% using snow cover extent from the Landsat Thematic Mapper. The validated model then evaluated the inter- and intra-year sensitivity of basin wide snowpack to projected temperature increases (2 °C) and variability in precipitation (±10%). Results show that a 2 °C increase in temperature would shift the average date of peak snowpack 12 days earlier and decrease basin-wide volumetric snow water storage by 56%. Snowpack between the elevations of 1000 and 2000 m is the most sensitive to increases in temperature. Upper elevations were also affected, but to a lesser degree. Temperature increases are the primary driver of diminished snowpack accumulation, however variability in precipitation produce discernible changes in the timing and volumetric storage of snowpack. The results of this study are regionally relevant as melt water from the MRB's snowpack provides critical water supply for agriculture, ecosystems, and municipalities throughout the region especially in summer when water demand is high. While this research focused on one watershed, it serves as a case study examining the effects of climate change on maritime snow, which comprises 10% of the Earth's seasonal snow cover.
Evidence of non-Darcy flow and non-Fickian transport in fractured media at laboratory scale
Authors: Cherubini C. , Giasi C. I. , Pastore N.
Published: July 2013

Abstract. During a risk assessment procedure as well as when dealing with cleanup and monitoring strategies, accurate predictions of solute propagation in fractured rocks are of particular importance when assessing exposure pathways through which contaminants reach receptors. Experimental data obtained under controlled conditions such as in a laboratory allow to increase the understanding of the fundamental physics of fluid flow and solute transport in fractures. In this study, laboratory hydraulic and tracer tests have been carried out on an artificially created fractured rock sample. The tests regard the analysis of the hydraulic loss and the measurement of breakthrough curves for saline tracer pulse inside a rock sample of parallelepiped shape (0.60 × 0.40 × 0.08 m). The convolution theory has been applied in order to remove the effect of the acquisition apparatus on tracer experiments. The experimental results have shown evidence of a non-Darcy relationship between flow rate and hydraulic loss that is best described by Forchheimer's law. Furthermore, in the flow experiments both inertial and viscous flow terms are not negligible. The observed experimental breakthrough curves of solute transport have been modeled by the classical one-dimensional analytical solution for the advection–dispersion equation (ADE) and the single rate mobile–immobile model (MIM). The former model does not properly fit the first arrival and the tail while the latter, which recognizes the existence of mobile and immobile domains for transport, provides a very decent fit. The carried out experiments show that there exists a pronounced mobile–immobile zone interaction that cannot be neglected and that leads to a non-equilibrium behavior of solute transport. The existence of a non-Darcian flow regime has showed to influence the velocity field in that it gives rise to a delay in solute migration with respect to the predicted value assuming linear flow. Furthermore, the presence of inertial effects enhance non-equilibrium behavior. Instead, the presence of a transitional flow regime seems not to exert influence on the behavior of dispersion. The linear-type relationship found between velocity and dispersion demonstrates that for the range of imposed flow rates and for the selected path the geometrical dispersion dominates the mixing processes along the fracture network.
The impact of forest regeneration on streamflow in 12 mesoscale humid tropical catchments
Authors: Beck H. E. , Bruijnzeel L. A. , van Dijk A. I. J. M. , McVicar T. R. , Scatena F. N. , Schellekens J.
Published: July 2013

Abstract. Although regenerating forests make up an increasingly large portion of humid tropical landscapes, little is known of their water use and effects on streamflow (Q). Since the 1950s the island of Puerto Rico has experienced widespread abandonment of pastures and agricultural lands, followed by forest regeneration. This paper examines the possible impacts of these secondary forests on several Q characteristics for 12 mesoscale catchments (23–346 km2; mean precipitation 1720–3422 mm yr−1) with long (33–51 yr) and simultaneous records for Q, precipitation (P), potential evaporation (PET), and land cover. A simple spatially-lumped, conceptual rainfall–runoff model that uses daily P and PET time series as inputs (HBV-light) was used to simulate Q for each catchment. Annual time series of observed and simulated values of four Q characteristics were calculated. A least-squares trend was fitted through annual time series of the residual difference between observed and simulated time series of each Q characteristic. From this the total cumulative change (Â) was calculated, representing the change in each Q characteristic after controlling for climate variability and water storage carry-over effects between years. Negative values of Â were found for most catchments and Q characteristics, suggesting enhanced actual evaporation overall following forest regeneration. However, correlations between changes in urban or forest area and values of Â were insignificant (p ≥ 0.389) for all Q characteristics. This suggests there is no convincing evidence that changes in the chosen Q characteristics in these Puerto Rican catchments can be ascribed to changes in urban or forest area. The present results are in line with previous studies of meso- and macro-scale (sub-)tropical catchments, which generally found no significant change in Q that can be attributed to changes in forest cover. Possible explanations for the lack of a clear signal may include errors in the land cover, climate, Q, and/or catchment boundary data; changes in forest area occurring mainly in the less rainy lowlands; and heterogeneity in catchment response. Different results were obtained for different catchments, and using a smaller subset of catchments could have led to very different conclusions. This highlights the importance of including multiple catchments in land-cover impact analysis at the mesoscale.
Summer sea ice characteristics and morphology in the Pacific Arctic sector as observed during the CHINARE 2010 cruise
Authors: Xie H. , Lei R. , Ke C. , Wang H. , Li Z. , Zhao J. , Ackley S. F.
Published: July 2013

Abstract. In the summer of 2010, atmosphere–ice–ocean interaction was studied aboard the icebreaker R/V Xuelong during the Chinese National Arctic Research Expedition (CHINARE), in the sea ice zone of the Pacific Arctic sector between 150° W and 180° W up to 88.5° N. The expedition lasted from 21 July to 28 August and comprised of ice observations and measurements along the cruise track, 8 short-term stations and one 12-day drift station. Ship-based observations of ice thickness and concentration are compared with ice thickness measured by an electromagnetic induction device (EM31) mounted off the ship's side and ice concentrations obtained from AMSR-E. It is found that the modal thickness from ship-based visual observations matches well with the modal thickness from the mounted EM31. A grid of 8 profiles of ice thickness measurements (four repeats) was conducted at the 12-day drift station in the central Arctic (~ 86°50´ N–87°20´ N) and an average melt rate of 2 cm day−1, primarily bottom melt, was found. As compared with the 2005 data from the Healy/Oden Trans-Arctic Expedition (HOTRAX) for the same sector but ~ 20 days later (9 August to 10 September), the summer 2010 was first-year ice dominant (vs. the multi-year ice dominant in 2005), 70% or less in mean ice concentration (vs. 90% in 2005), and 94–114 cm in mean ice thickness (vs. 150 cm in 2005). Those changes suggest the continuation of ice thinning, less concentration, and younger ice for the summer sea ice in the sector since 2007 when a record minimum sea ice extent was observed. Overall, the measurements provide a valuable dataset of sea ice morphological properties over the Arctic Pacific Sector in summer 2010 and can be used as a benchmark for measurements of future changes.
La conservación de bienes culturales muebles en El Salvador: Una tarea por hacer
Authors: Castillo Beatriz
Published: July 2013

La conservación y restauración ha tomado un lugar preponderante para la cultura en todo el mundo. “Desde la antigüedad, y más específicamente desde la época medieval, el renacimiento o el barroco, se aplicaban prácticas para la conservación de edificios, pinturas murales, esculturas y pinturas con un enfoque de prevención del deterioro”1. La institución responsable de recolectar, estudiar, conservar y exhibir el patrimonio cultural que forma sus colecciones es el museo, en cualquiera de sus expresiones. La actividad de mayor responsabilidad que se deriva es la conservación, ya que sin obras en buen estado no existen materiales para exhibir. DOI: http://dx.doi.org/10.5377/koot.v0i2.1150 Revista de Museología "Kóot" No.2 2010: 27-36
Formas y significados del vestido en una sociedad posmoderna: el caso de San Salvador
Authors: Hernández Moncada Mariella , Regina Campos Melissa
Published: July 2013

Entre las formas de cultura creadas por el ser humano en sociedad está el modo de vestir, y, a pesar de que necesidades funcionales del vestido varían de una sociedad o región a otra al encontrarse presente en todas y cada una de ellas, esto lo vuelve un hecho universal. Ciertamente, la vestimenta surge con la básica finalidad de dar respuesta a la necesidad de abrigo. Y si el uso de la vestimenta es universal, lo que la hace diferente en cada grupo humano es el desarrollo independiente de sus propios patrones, llegando incluso a ser uno de los fuertes rasgos identitarios de cada grupo social. Así, el estudio del vestido no puede separarse del entorno cultural al cual pertenece, pues sus formas básicas se aplican a unos cánones o normas impuestas por la cultura misma. DOI: http://dx.doi.org/10.5377/koot.v0i2.1152 Revista de Museología "Kóot" No.2 2010: 45-68
Remembranzas de un departamento de Arqueología con los primeros arqueólogos formados en El Salvador
Authors: Valdivieso Fabricio
Published: July 2013

Supe de un caso, como muchos han de haber, de un empleado que había dedicado treinta y cinco años de trabajo a su institución. En el camino había dejado muchos recuerdos y amigos, quienes en su mayoría hace algún tiempo abandonaron la entidad. Se aproximaba la hora de su retiro. Entre sus compañeros de trabajo, de una generación mucho más joven, aquello no fue más que un sencillo y ligero adiós… DOI: http://dx.doi.org/10.5377/koot.v0i2.1154 Revista de Museología "Kóot" No.2 2010: 77-100
Chemical Composition and Trypanocidal Activity of the Essential Oils from Hedychium coronarium J. Koenig (Zingiberaceae)
Authors: Rodrigues Danilo Fernando , Arenas Velásquez Angela María , Cavaleiro Carlos , Salgueiro Lígia , Martins Gilmárcio Zimmermann , Magalhães Nathália Oliveira , Martins Maria Bernadete Gonçalves , Cicarelli Regina Maria Barretto , Moreira Raquel Regina Duarte
Published: July 2013

The composition of the essential oils (EO) from leaves and rhizomes of Hedychium coronarium was analyzed both by gas chromatography and gas chromatography-mass spectroscopy. Thirty and thirty-nine compounds were identified, respectively, in the oils from leaves and rhizomes, representing 88% and 86.1% of the whole compositions. Caryophyllene oxide is the major component in rhizomes while 1,8-cineole predominates in leaves oil. Essential oils and major components were tested for trypanocidal activity using procyclic forms of Trypanosoma brucei (427 and 29-13 strains). The cytotoxicity index (CI50), using the MTT colorimetric method, showed that essential oils and 1,8-cineole were inactive (>100 μg·mL−1. Nevertheless, caryophyllene oxide revealed a remarkable activity against both T. brucei strains (CI50 = 65.77 μg·mL−1 and 24.53 μg·mL−1, resp.), and the synergism between caryophyllene oxide plus pentamidine (1 : 1, v/v) highly increased the trypanocidal activity (<1.0 μg·mL−1).
A Tribute to Andrzej Przewoźnik on the Seventieth Anniversary of the Discovery of the Katyń Crime
Authors: Cienciała Anna M.
Published: July 2013

Based on the book: Andrzej Przewoźnik and, Jolanta Adamska, Katyń. Zbrodnia, Prawda, Pamiƙć [Katyń. Crime, Truth, Memory]; Preface by Jerzy Buzek, Introduction by Jolanta Adamska (Warsaw: Świat Książki, 2010), 672 pp. incl. index, illustrations. ISBN 978-83-247-1; Nr 7823. Andrzej Przewoźnik (1963-2010) accomplished more in his short life than most individuals. A historian, he devoted himself to memorializing the Katyń massacre, on Stalin’s orders in the spring of 1940, of thousands of Polish officers, policemen and civilians held in special camps and NKVD prisons. His book on Katyń, reviewed here, is the most detailed account so far of the antecedents, the crime, its investigation, and his role in the exhumations, negotiations for war cemeteries and their construction. He died near Katyń, with ninety-five others, in the crash of the Polish presidential plane at Smolensk on April 10, 2010. He has memorial tablets in several Polish towns; this review article is a memorial to him in English.
The Place of Transformative Learning in the Building of Learning Cities in Africa
Authors: Biao Idowu
Published: July 2013

This article argues that the learning city concept, which is an international initiative devoted to the promotion of sustainable, healthy, green and economically viable cities by the means of lifelong learning, is currently operational in Europe, the Americas, Australia and Asia but absent in Africa.

The main point made by the article is that the introduction of learning city projects into Africa will succeed only if this continent's historical, cultural and epistemological realities are relied upon in the selection of an entry methodology. That methodology is here identified as ‘transformative learning’. Transformative learning is a process of learning that begins human transformation from within and moves outwardly. It is recommended as an appropriate methodology for introducing the learning city concept into Africa because an inner transformation that would enable Africans to reconcile their two concepts of city (ancient and modern) is required for the successful take-off of learning city projects in Africa.

Although transformative learning counts a number of perspectives, the conscientisation and afrocentric perspectives are here specifically recommended for use because they embody the icons and strategies that may prove effective in introducing the learning city concept into Africa.
Anatomies of Inequality: Considering the Emotional Cost of Aiming Higher for Marginalised, Mature Mothers Re-Entering Education
Authors: Mannay Dawn , Morgan Melanie
Published: July 2013

The Anatomy of Economic Inequality in Wales (2011) provides quantitative evidence for the pervasive nature of class-based inequalities in education, demonstrating that an individual in social housing is approximately 10 times less likely to be a graduate compared to those in other types of accommodation. This article moves beyond the baseline figures and argues that for marginalised, mature mothers re-entering education, the emotional cost is often one that they are unable to pay, and that practitioners and policy makers need to be aware of, and responsive to their situation so that retention and completion rates can be improved. The article presents case studies from two research projects, which aimed to explore and represent the educational experiences of working-class mature students in urban south Wales. The article focuses on the accounts of women who completed Access courses and gained places in post-1992 universities, focusing on their initial aspirations and later disappointments. The article examines the ways in which classed, gendered and relational positionings conflicted with their education trajectory and often contributed to their withdrawal from academia.
Condoms and condiments: compatibility and safety of personal lubricants and their use in Africa
Authors: Geibel Scott
Published: July 2013

Previous research on the use of personal lubricants for sexual intercourse is limited and has primarily focused on condom compatibility and breakage, with only recent limited assessment of lubricant safety and possible epidemiologic implications. This article discusses the global evidence of lubricant compatibility with latex condoms and biological safety of lubricants, as well as documentation of lubricant use and current guidelines for HIV prevention programming in Africa. Data on lubricant compatibility with condoms are less available than commonly realized, and many lubricant products may not have been thoroughly tested for safety due to flexible regulatory environments. Recent laboratory and study findings from microbicides research also suggest that some water‐based lubricants may have safety issues. Some African populations are using several types of lubricants, especially oil‐based petroleum jellies, and receive little evidence‐based guidance. More research is needed from the medical community to guide prevention programming.
Skill learning strengthens cortical representations of motor sequences
Authors: Wiestler Tobias , Diedrichsen Jörn
Published: July 2013

Motor-skill learning can be accompanied by both increases and decreases in brain activity. Increases may indicate neural recruitment, while decreases may imply that a region became unimportant or developed a more efficient representation of the skill. These overlapping mechanisms make interpreting learning-related changes of spatially averaged activity difficult. Here we show that motor-skill acquisition is associated with the emergence of highly distinguishable activity patterns for trained movement sequences, in the absence of average activity increases. During functional magnetic resonance imaging, participants produced either four trained or four untrained finger sequences. Using multivariate pattern analysis, both untrained and trained sequences could be discriminated in primary and secondary motor areas. However, trained sequences were classified more reliably, especially in the supplementary motor area. Our results indicate skill learning leads to the development of specialized neuronal circuits, which allow the execution of fast and accurate sequential movements without average increases in brain activity.
Closing in on a new treatment for sleeping sickness
Authors: Derbyshire Emily R , Clardy Jon
Published: July 2013

A chemoproteomics approach has been employed to identify a kinase that could be used as a druggable target in efforts to develop new treatments for African sleeping sickness.
Building a Live Cell Microscope: What You Need and How to Do It
Authors: Watkins Simon C. , St. Croix Claudette M.
Published: July 2013

In this post‐genomic era, the predominant focus of biomedical research has moved towards elucidating the functionality of molecules at the cellular and subcellular level in integrated living systems. As such, biologic imaging has moved beyond the collection of static “snapshots” of the cellular state to the real‐time visualization of cellular and molecular behavior in three‐dimensional (3D) space. Live‐cell imaging techniques can be used to assess protein abundance, as well as determine the functional role(s) and interactions of multiple unique molecules concurrently within the cellular environment, and determine the effects of these molecules on cell development, organization, and fate over extended periods of time. Such studies require advanced systems that allow multiparametric analysis of cells while maintaining their functional viability. This unit will focus on the design and implementation of modern live‐cell imaging systems. We will examine the principle problems facing live‐cell microscopists including: focus drift, cell viability, photo‐toxicity, and data acquisition, and suggest appropriate solutions to these issues. Our goal in this unit is to provide individual scientists with the information required to implement live‐cell imaging solutions within their own laboratories. Curr. Protoc. Cytom. 65:2.21.1‐2.21.10. © 2013 by John Wiley & Sons, Inc.
Kinetic Viability Assays Using DRAQ7 Probe
Authors: Wlodkowic Donald , Akagi Jin , Dobrucki Jurek , Errington Rachel , Smith Paul J , Takeda Kazuo , Darzynkiewicz Zbigniew
Published: July 2013

Cell death within cell populations is a stochastic process where cell‐to‐cell variation in temporal progression through the various stages of cell death arises from asynchrony of subtle fluctuations in the signaling pathways. Most cell death assays rely on detection of the specific marker of cell demise at the end‐point of cell culturing. Such an approach cannot account for the asynchrony and the stochastic nature of cell response to the death‐inducing signal. There is a need therefore for rapid and high‐throughput bioassays capable of continuously tracking viability of individual cells from the time of encountering a stress signal up to final stages of their demise. In this context, a new anthracycline derivative, DRAQ7, is gaining increasing interest as an easy‐to‐use marker capable of long‐term monitoring of cell death in real‐time. This novel probe neither penetrates the plasma membrane of living cells nor does it affect the cells' susceptibility to the death‐inducing agents. However, when the membrane integrity is compromised, DRAQ7 enters cells undergoing demise and binds readily to nuclear DNA to report cell death. Here, we provide three sets of protocols for viability assays using DRAQ7 probe. The first protocol describes the innovative use of single‐color DRAQ7 real‐time assay to dynamically track cell viability. The second protocol outlines a simplified end‐point DRAQ7 staining approach. The final protocol highlights the real‐time and multiparametric apoptosis assay utilizing DRAQ7 dye concurrently with tetramethylrhodamine methyl ester (TMRM), the mitochondrial trans‐membrane electrochemical potential (ΔΨm) sensing probe. Curr. Protoc. Cytom. 65:9.41.1‐9.41.8. © 2013 by John Wiley & Sons, Inc.
Cytometry in Malaria—A Practical Replacement for Microscopy?
Authors: Shapiro Howard M. , Apte Simon H. , Chojnowski Grace M. , Hänscheid Thomas , Rebelo Maria , Grimberg Brian T.
Published: July 2013

Malaria, caused by protozoan Plasmodium parasites, kills ∼800,000 people each year. Exact figures are uncertain because presumptive diagnoses are often made without identifying parasites in patients' blood either by microscopy, using Giemsa's century‐old stain, or by simpler tests that are ultimately dependent on microscopy for quality control. Microscopy itself relies on trained observers' ability to detect subtle morphological features of parasitized red blood cells, only a few of which may be present on a slide. Quantitative and objective flow cytometric measurements of cellular constituents such as DNA, RNA, and the malaria pigment hemozoin are now useful in research in malaria biology and pharmacology, and can provide more reliable identification of parasite species and developmental stages and better detection of low‐density parasitemia than could microscopy. The same measurements can now be implemented in much smaller, simpler, cheaper imaging cytometers, potentially providing a more accurate and precise diagnostic modality. Curr. Protoc. Cytom. 65:11.20.1‐11.20.23. © 2013 by John Wiley & Sons, Inc.
Processing, Properties, and Applications of Polymer Nanocomposites Based on Layer Silicates: A Review
Authors: Alateyah A. I. , Dhakal H. N. , Zhang Z. Y.
Published: July 2013

The nanocomposites are materials, which involve fillers in the nanometer scale, yielding substantial improvements. Polymer‐layered silicate nanocomposites have received much attention during the past decade and have great interest both in the academic field and in industry, since they often give more attractive improvement to material properties than both micro‐ and macrocomposite materials. This extensive review presents recent studies in polymer nanocomposites based on layered silicate. The background, morphology, preparations, and properties of these materials are discussed. The review covers and discusses various modern methods and equipments in the preparation of nanocomposites, deeply focusing on the morphology of nanocomposites and its effects on the overall properties. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21368; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21368
Association of BDNF gene polymorphisms with schizophrenia and clinical symptoms in a Chinese population
Authors: Li Wenjun , Zhou Na , Yu Qiong , Li Xiaokun , Yu Yaqin , Sun Shilong , Kou Changgui , Chen Da Chun , Xiu Mei Hong , Kosten Thomas R , Zhang Xiang Yang
Published: July 2013

The neurodevelopmental hypothesis is well established in schizophrenia. Accumulating evidence has shown that BDNF may be involved in the pathogenesis of schizophrenia. This study aimed to investigate the potential association of BDNF gene polymorphisms with susceptibility to schizophrenia and with the psychopathological symptoms in patients with schizophrenia in a Han Chinese population. Three polymorphisms (rs6265, rs12273539, and rs10835210) of the BDNF gene were analyzed in a case‐control study of 709 Han Chinese individuals (375 patients and 334 controls). The patients' psychopathology was assessed using the positive and negative syndrome scale (PANSS). We found no significant differences in the genotype and allele distributions of all three polymorphisms between the patient and control groups; however, we found a trend toward to significant overall difference in the estimated haplotype frequencies, with more frequent haplotype ATC of rs6265‐rs12273539‐rs10835210 in the schizophrenic patients than in controls (P = 0.027). The quantitative trait analysis by the UNPHASED program showed significant associations between the rs6265 (A)‐rs12273539 (C)‐rs10835210 (A) haplotype and negative symptom scores from the PANSS (x2 = 5.79, P = 0.016). Our findings suggest that the BDNF gene polymorphisms may play a small effect on susceptibility to schizophrenia, but may contribute to the negative symptoms of the disease. © 2013 Wiley Periodicals, Inc.
Preparation and characterization of a poly(vinyl alcohol)/tetraethoxysilane ultrafiltration membrane by a sol–gel method
Authors: Yuan Haikuan , Ren Jie , Cheng Liang , Shen Lian
Published: July 2013

Using poly(vinyl alcohol) (PVA) with highly hydrophilic properties as membrane material and poly(ethylene glycol) (PEG) as an additive, we prepared PVA/tetraethoxysilane (TEOS) ultrafiltration (UF) membranes with good antifouling properties by a sol–gel method. The PVA/TEOS UF membranes were characterized by X‐ray diffraction patterns, Fourier transform infrared spectroscopy, scanning electron microscopy, and static contact angle of measurement of water. The hybridization of TEOS to PVA for preparing the PVA/TEOS UF membranes achieved the required permeation performance and good antifouling behaviors. The morphology and permeation performance of the PVA/TEOS membranes varied with the different TEOS loadings and PEG contents. The pure water fluxes (JW) increased and the rejections (Rs) decreased with increasing TEOS loading and PEG content. The PVA/TEOS UF membrane with a PVA/TEOS/PEG/H2O composition mass ratio of 10/3/4/83 in the dope solution had a JW of 66.5 L m−2 h−1 and an R of 60.3% when we filtered it with 300 ppm of bovine serum albumin aqueous solution at an operational pressure difference of 0.1 MPa. In addition, the filtration and backwashing experiment proved that the PVA/TEOS membranes possessed good long‐term antifouling abilities. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4066–4074, 2013
Prediction of the gas solubility in polymers by a radial basis function neural network based on chaotic self‐adaptive particle swarm optimization and a clustering method
Authors: Li Mengshan , Huang Xingyuan , Liu Hesheng , Liu Bingxiang , Wu Yan
Published: July 2013

A novel model based on a radial basis function neural network (RBF NN), chaos theory, self‐adaptive particle swarm optimization (PSO), and a clustering method is proposed to predict the gas solubility in polymers; this model is hereafter called CSPSO‐C RBF NN. To develop the CSPSO‐C RBF NN, the conventional PSO was modified with chaos theory and a self‐adaptive inertia weight factor to overcome its premature convergence problem. The classical k‐means clustering method was used to tune the hidden centers and radial basis function spreads, and the modified PSO algorithm was used to optimize the RBF NN connection weights. Then, the CSPSO‐C RBF NN was used to investigate the solubility of N2 in polystyrene (PS) and CO2 in PS, polypropylene, poly(butylene succinate), and poly(butylene succinate‐co‐adipate). The results obtained in this study indicate that the CSPSO‐C RBF NN was an effective method for predicting the gas solubility in polymers. In addition, compared with conventional RBF NN and PSO neural network, the CSPSO‐C RBF NN showed better performance. The values of the average relative deviation, squared correlation coefficient, and standard deviation were 0.1282, 0.9970, and 0.0115, respectively. The statistical data demonstrated that the CSPSO‐C RBF NN had excellent prediction capabilities with a high accuracy and a good correlation between the predicted values and the experimental data. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3825–3832, 2013
Meritocracy, deficit thinking and the invisibility of the system: Discourses on educational success and failure
Authors: Clycq Noel , Ward Nouwen M. A. , Vandenbroucke Anneloes
Published: July 2013

Socio‐ethnic stratification and segregation processes present in Flemish society are reflected in the everyday school environment. Pupils with a different socio‐ethnic background than the dominant majority and middle class seem to be confronted with a lot of difficulties in this school system. The dominant meritocratic discourse frequently applies a deficit thinking perspective to frame educational success and failure, focusing on deficiencies originating outside of the school. In this paper we analyse newly collected survey data (N = 11,015 pupils) and a large amount of qualitative data (from pupils, parents, teachers, principals) to answer our two main research questions: (i) how is educational success/failure defined, and (ii) how is educational success/failure explained? The factor analyses as well as the qualitative analyses illustrate how the idea of meritocracy relates to individualistic features such as effort, merit and competence. However, the findings also reveal that this individualistic approach goes hand‐in‐hand with a focus on the family environment and ‘culture’ which seems to limit individual agency to a large extent. In these discourses, pupils, parents and even teachers are presented as being largely determined by their direct social environment with almost no regard for social inequalities within the educational system. The paper ends with a discussion on how processes of victimization and the denial of systemic bias, influence educational trajectories and proposes a different approach to multiculturalism and the appreciation of cultural background and specific family resources as positive elements in these trajectories.
Separation and nanoencapsulation of antitumor polypeptide from Spirulina platensis
Authors: Zhang Bochao , Zhang Xuewu
Published: July 2013

Spirulina platensis is a multicellular edible blue‐green alga with abundant proteins (∼60%). No report is available on the antitumor polypeptides from the whole proteins of S. platensis. In this study, for the first time, an antitumor polypeptide Y2 from trypsin digest of S. platensis proteins was obtained by using freeze‐thawing plus ultrasonication extraction, hydrolysis with four enzymes (trypsin, alcalase, papain, and pepsin), and gel filtration chromatography. The results showed that the degree of hydrolysis can be ordered as: trypsin (38.5%) > alcalase (31.2%) > papain (27.8%) > pepsin (7.1%). For MCF‐7 and HepG2 cells, at 250 µg/mL, the maximum inhibitory rate of Y2 was 97%, while standard drug 5‐FU was 55 and 97%, respectively. Furthermore, the nanoencapsulation of Y2 with chitosan (CS) was also investigated. After nanoencapsulation, the maximum encapsulation efficiency and polypeptides contents are 49 and 15%, respectively; and the antitumor activity is basically not lost. These data demonstrated the potential of nanopolypeptides (Y2‐CS) in food and pharmaceutical applications. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:1230–1238, 2013
Power‐law hereditariness of hierarchical fractal bones
Authors: Deseri Luca , Paola Mario Di , Zingales Massimiliano , Pollaci Pietro
Published: July 2013

In this paper, the authors introduce a hierarchic fractal model to describe bone hereditariness. Indeed, experimental data of stress relaxation or creep functions obtained by compressive/tensile tests have been proved to be fit by power law with real exponent 0 ⩽ β ⩽1. The rheological behavior of the material has therefore been obtained, using the Boltzmann–Volterra superposition principle, in terms of real order integrals and derivatives (fractional‐order calculus). It is shown that the power laws describing creep/relaxation of bone tissue may be obtained by introducing a fractal description of bone cross‐section, and the Hausdorff dimension of the fractal geometry is then related to the exponent of the power law. Copyright © 2013 John Wiley & Sons, Ltd.
A secure cost‐effective migration of enterprise applications to the cloud
Authors: Huang Daochao , Yi Li , Song Fei , Yang Dong , Zhang Hongke
Published: July 2013

Cloud computing is rapidly expanding as an alternative service deployment platform today. This brings forth many new challenges in migrating enterprise applications into cloud. To enable enterprises to benefit from migration while achieving cost‐efficiency and keeping sensitive user data confidential against untrusted servers, planning which servers to migrate to the cloud and which to be hosted on‐premise is a key problem. This problem has been traditionally approached through the formulation and resolution of large optimization problems requiring global knowledge. Such approaches are not suitable for large‐scale and dynamic enterprise network migrations.

In this paper, the problem of determining the optimal migrated components set of an enterprise application is revisited and addressed in a way that is both scalable and deals inherently with network dynamicity. In particular, application migration, which enables service components to move between local data center toward more communication cost‐effective cloud, is based on local information. The migration policies proposed in this work are analytically shown to be capable of moving an enterprise application between local data center and remote cloud in a way that the cost of service provision is reduced. Experimental results show the efficiency, applicability, and easy adaptability of the presented approach.Copyright © 2013 John Wiley & Sons, Ltd.
Efficient algorithms for scheduling multiple bulk data transfers in inter‐datacenter networks
Authors: Su Sen , Wang Yiwen , Jiang Sujuan , Shuang Kai , Xu Peng
Published: July 2013

Bulk data transfers, such as backups and propagation of bulky updates, account for a large portion of the inter‐datacenter traffic. These bulk transfers consume massive bandwidth and further increase the operational cost of datacenters. The advent of store‐and‐forward transfer mode offers the opportunity for cloud provider companies to transfer bulk data by utilizing dynamic leftover bandwidth resources. In this paper, we study the multiple bulk data transfers scheduling problem in inter‐datacenter networks with dynamic link capacities. To improve the network utilization while guaranteeing fairness among requests, we employ the max–min fairness and aim at computing the lexicographically maximized solution. Leveraging the time‐expanded technique, the problem in dynamic networks is formulated as a static multi‐flow model. Then, we devise an optimal algorithm to solve it simultaneously from routing assignments and bandwidth allocation. To further reduce the computational cost, we propose to select an appropriate number of disjoint paths for each request. Extensive simulations are conducted on a real datacenter topology and prove that (i) benefiting from max–min fairness, the network utilization is significantly improved while honoring each individual performance; (ii) a small number of disjoint paths per request are sufficient to obtain the near optimal allocation within practical execution time. Copyright © 2013 John Wiley & Sons, Ltd.