bluuebunny/crossref_metadata_2025 huggingface dataset:
Vertical profiles of droplet effective radius in shallow convective clouds
Authors: Zhang S. , Xue H. , Feingold G.
Published: May 2011

Abstract. Conventional satellite retrievals can only provide information on cloud-top droplet effective radius (re). Given the fact that cloud ensembles in a satellite snapshot have different cloud-top heights, Rosenfeld and Lensky (1998) used the cloud-top height and the corresponding cloud-top re from the cloud ensembles in the snapshot to construct a profile of re representative of that in the individual clouds. This study investigates the robustness of this approach in shallow convective clouds based on results from large-eddy simulations (LES) for clean (aerosol mixing ratio Na = 25 mg−1), intermediate (Na = 100 mg−1), and polluted (Na = 2000 mg−1) conditions. The cloud-top height and the cloud-top re from the modeled cloud ensembles are used to form a constructed re profile, which is then compared to the in-cloud re profiles. For the polluted and intermediate cases where precipitation is negligible, the constructed re profiles represent the in-cloud re profiles fairly well with a low bias (about 10 %). The method used in Rosenfeld and Lensky (1998) is therefore validated for nonprecipitating shallow cumulus clouds. For the clean, drizzling case, the in-cloud re can be very large and highly variable, and quantitative profiling based on cloud-top re is less useful. The differences in re profiles between clean and polluted conditions derived in this manner are however, distinct. This study also investigates the subadiabatic characteristics of the simulated cumulus clouds to reveal the effect of mixing on re and its evolution. Results indicate that as polluted and moderately polluted clouds develop into their decaying stage, the subadiabatic fraction fad becomes smaller, representing a higher degree of mixing, and re becomes smaller (~10 %) and more variable. However, for the clean case, smaller fad corresponds to larger re (and larger re variability), reflecting the additional influence of droplet collision-coalescence and sedimentation on re. Finally, profiles of the vertically inhomogeneous clouds as simulated by the LES and those of the vertically homogeneous clouds are used as input to a radiative transfer model to study the effect of cloud vertical inhomogeneity on shortwave radiative forcing. For clouds that have the same liquid water path, re of a vertically homogeneous cloud must be about 76–90 % of the cloud-top re of the vertically inhomogeneous cloud in order for the two clouds to have the same shortwave radiative forcing.
Black carbon aerosol mixing state, organic aerosols and aerosol optical properties over the UK
Authors: McMeeking G. R. , Morgan W. T. , Flynn M. , Highwood E. J. , Turnbull K. , Haywood J. , Coe H.
Published: May 2011

Abstract. Black carbon (BC) aerosols absorb sunlight thereby leading to a positive radiative forcing and a warming of climate and can also impact human health through their impact on the respiratory system. The state of mixing of BC with other aerosol species, particularly the degree of internal/external mixing, has been highlighted as a major uncertainty in assessing its radiative forcing and hence its climate impact, but few in situ observations of mixing state exist. We present airborne single particle soot photometer (SP2) measurements of refractory BC (rBC) mass concentrations and mixing state coupled with aerosol composition and optical properties measured in urban plumes and regional pollution over the UK. All data were obtained using instrumentation flown on the UK's BAe-146-301 large Atmospheric Research Aircraft (ARA) operated by the Facility for Airborne Atmospheric Measurements (FAAM). We measured sub-micron aerosol composition using an aerosol mass spectrometer (AMS) and used positive matrix factorization to separate hydrocarbon-like (HOA) and oxygenated organic aerosols (OOA). We found a higher number fraction of thickly coated rBC particles in air masses with large OOA relative to HOA, higher ozone-to-nitrogen oxides (NOx) ratios and large concentrations of total sub-micron aerosol mass relative to rBC mass concentrations. The more ozone- and OOA-rich air masses were associated with transport from continental Europe, while plumes from UK cities had higher HOA and NOx and fewer thickly coated rBC particles. We did not observe any significant change in the rBC mass absorption efficiency calculated from rBC mass and light absorption coefficients measured by a particle soot absorption photometer despite observing significant changes in aerosol composition and rBC mixing state. The contributions of light scattering and absorption to total extinction (quantified by the single scattering albedo; SSA) did change for different air masses, with lower SSA observed in urban plumes compared to regional aerosol (0.85 versus 0.9–0.95). We attribute these differences to the presence of relatively rapidly formed secondary aerosol, primarily OOA and ammonium nitrate, which must be taken into account in radiative forcing calculations.
First correlated measurements of the shape and scattering properties of cloud particles using the new Particle Habit Imaging and Polar Scattering (PHIPS) probe
Authors: Abdelmonem A. , Schnaiter M. , Amsler P. , Hesse E. , Meyer J. , Leisner T.
Published: May 2011

Abstract. Studying the radiative impact of cirrus clouds requires the knowledge of the link between their microphysics and the single scattering properties of the cloud particles. Usually, this link is created by modeling the optical scattering properties from in situ measurements of ice crystal size distributions. The measured size distribution and the assumed particle shape might be erroneous in case of non-spherical ice particles. We present here a novel optical sensor (the Particle Habit Imaging and Polar Scattering probe, PHIPS) designed to measure the 3-D morphology and the corresponding optical and microphysical parameters of individual cloud particles, simultaneously. Clouds containing particles ranging in size from a few micrometers to about 800 μm diameter can be systematically characterized with an optical resolution power of 2 μm and polar scattering resolution of 1° for forward scattering directions (from 1° to 10°) and 8° for side and backscattering directions (from 18° to 170°). The maximum acquisition rates for scattering phase functions and images are 262 KHz and 10 Hz, respectively. Some preliminary results collected in two ice cloud campaigns which were conducted in the AIDA cloud simulation chamber are presented. PHIPS showed reliability in operation and produced comparable size distributions and images to those given by other certified cloud particles instruments. A 3-D model of a hexagonal ice plate is constructed and the corresponding scattering phase function is compared to that modeled using the Ray Tracing with Diffraction on Facets (RTDF) program. PHIPS is candidate to be a novel air borne optical sensor for studying the radiative impact of cirrus clouds and correlating the particle habit-scattering properties which will serve as a reference for other single, or multi-independent, measurements instruments.
An unheated permeation device for calibrating atmospheric VOC measurements
Authors: Brito J. , Zahn A.
Published: May 2011

Abstract. The development of an unpowered permeation device for continuous calibration of in-situ instruments measuring atmospheric volatile organic compounds (VOCs) is described. Being lightweight and compact, and containing only negligible amounts of chemicals, the device is especially suited for field use such as onboard aircraft. Its speciality is to maintain the permeation process in thermal equilibrium, i.e. the instantaneous permeation rate can be ascribed via a simple temperature measurement. This equilibrium state is maintained by a combination of three features: (i) a thin PTFE membrane as permeation medium which guarantees short stabilization times, (ii) a water bath as heat buffer, and (iii) a vacuum-panel based insulation, in which features (ii) and (iii) minimize temperature drifts. The uncertainty of the permeation rate due to thermal non-equilibrium is kept below 1 %. An extensive theory part details the major permeation processes of gases through porous polymers, being Fick's diffusion, Knudsen flow, and viscous flow. Both the measured stabilization time and the measured temperature dependence of the permeation rate independently indicate that the permeation can be described by a viscous flow model, where diffusion of the gas molecules in large pores (having a diameter of >0.05 μm) dominates.
Data-driven exploration of orographic enhancement of precipitation
Authors: Foresti L. , Kanevski M. , Pozdnoukhov A.
Published: May 2011

Abstract. This study presents a methodology to analyse orographic enhancement of precipitation using sequences of radar images and a digital elevation model. Image processing techniques are applied to extract precipitation cells from radar imagery. DEM is used to derive the topographic indices potentially relevant to orographic precipitation enhancement at different spatial scales, e.g. terrain convexity and slope exposure to mesoscale flows. Two recently developed machine learning algorithms are then used to analyse the relationship between the repeatability of precipitation patterns and the underlying topography. Spectral clustering is first used to characterize stratification of the precipitation cells according to different mesoscale flows and exposure to the crest of the Alps. At a second step, support vector machine classifiers are applied to build a computational model which discriminates persistent precipitation cells from all the others (not showing a relationship to topography) in the space of topographic conditioning factors. Upwind slopes and hill tops were found to be the topographic features leading to precipitation repeatability and persistence. Maps of orographic enhancement susceptibility can be computed for a given flow, topography and forecasted smooth precipitation fields and used to improve nowcasting models or correct windward and leeward biases in numerical weather prediction models.
Seasonal variations of belowground carbon transfer assessed by in situ 13CO2 pulse labelling of trees
Authors: Epron D. , Ngao J. , Dannoura M. , Bakker M. R. , Zeller B. , Bazot S. , Bosc A. , Plain C. , Lata J. C. , Priault P. , Barthes L. , Loustau D.
Published: May 2011

Abstract. Soil CO2 efflux is the main source of CO2 from forest ecosystems and it is tightly coupled to the transfer of recent photosynthetic assimilates belowground and their metabolism in roots, mycorrhiza and rhizosphere microorganisms feeding on root-derived exudates. The objective of our study was to assess patterns of belowground carbon allocation among tree species and along seasons. Pure 13CO2 pulse labelling of the entire crown of three different tree species (beech, oak and pine) was carried out at distinct phenological stages. Excess 13C in soil CO2 efflux was tracked using tuneable diode laser absorption spectrometry to determine time lags between the start of the labelling and the appearance of 13C in soil CO2 efflux and the amount of 13C allocated to soil CO2 efflux. Isotope composition (δ13C) of CO2 respired by fine roots and soil microbes was measured at several occasions after labelling, together with δ13C of bulk root tissue and microbial carbon. Time lags ranged from 0.5 to 1.3 days in beech and oak and were longer in pine (1.6–2.7 days during the active growing season, more than 4 days during the resting season), and the transfer of C to the microbial biomass was as fast as to the fine roots. The amount of 13C allocated to soil CO2 efflux was estimated from a compartment model. It varied between 1 and 21 % of the amount of 13CO2 taken up by the crown, depending on the species and the season. While rainfall exclusion that moderately decreased soil water content did not affect the pattern of carbon allocation to soil CO2 efflux in beech, seasonal patterns of carbon allocation belowground differed markedly between species, with pronounced seasonal variations in pine and beech. In beech, it may reflect competition with the strength of other sinks (aboveground growth in late spring and storage in late summer) that were not observed in oak. We report a fast transfer of recent photosynthates to the mycorhizosphere and we conclude that the patterns of carbon allocation belowground are species specific and change seasonally according to the phenology of the species.
Influence of intense scavenging on Pa-Th fractionation in the wake of Kerguelen Island (Southern Ocean)
Authors: Venchiarutti C. , Roy-Barman M. , Freydier R. , van Beek P. , Souhaut M. , Jeandel C.
Published: May 2011

Abstract. Dissolved and particulate excess 230Th and 231Pa concentrations (noted 230Thxs and 231Paxs, respectively) and 231Paxs/230Thxs activity ratios were investigated on and out of the Kerguelen plateau (Southern Ocean) in the framework of the KErguelen Ocean and Plateau compared Study project in order to better understand the influence of particle flux and particle chemistry and advection on the scavenging of 231Pa. In the wake of Kerguelen Island, the relative abundance of 231Paxs in the particles compared to the dissolved phase associated with a low fractionation factor between 230Th and 231Pa (FTh/Pa ranging from 0.06 ± 0.01 to 2.13 ± 0.63) is consistent with particles being dominated by biogenic silica in this area. Strong 231Pa concentration gradients occur on relatively short distances. Along the eastern escarpment of the Kerguelen plateau, an intensive scavenging affects significantly the dissolved distribution of 231Paxs at depth, as already observed for 230Thxs. This local boundary scavenging was attributed to re-suspension of opal-rich particles by nepheloid layers, resulting in fractionation factors FTh/Pa ≤ 1 along the Kerguelen plateau slope. Therefore, these results showed that in the Kerguelen wake, both the composition (biogenic opal) and the flux (intensive along the margin) of particles control the scavenging of the two radionuclides. The modelling of 231Pa distribution with an advection-scavenging model demonstrate that lateral advection of open ocean water on the Kerguelen plateau could supply most of the 231Pa, which is then efficiently scavenged on the highly productive plateau, as previously proposed for 230Thxs. It stresses that lateral advection can play a significant role in the overall budget of particle reactive trace elements in a coastal-open ocean system.
MIROC-ESM: model description and basic results of CMIP5-20c3m experiments
Authors: Watanabe S. , Hajima T. , Sudo K. , Nagashima T. , Takemura T. , Okajima H. , Nozawa T. , Kawase H. , Abe M. , Yokohata T. , Ise T. , Sato H. , Kato E. , Takata K. , Emori S. , Kawamiya M.
Published: May 2011

Abstract. An earth system model (MIROC-ESM) is fully described in terms of each model component and their interactions. Results for the CMIP5 (Coupled Model Intercomparison Project phase 5) historical simulation are presented to demonstrate the model's performance from several perspectives: atmosphere, ocean, sea-ice, land-surface, ocean and terrestrial biogeochemistry, and atmospheric chemistry and aerosols. An atmospheric chemistry coupled version of MIROC-ESM (MIROC-ESM-CHEM) reasonably reproduces transient variations in surface air temperatures for the period 1850–2005, as well as the present-day climatology for the zonal-mean zonal winds and temperatures from the surface to the mesosphere. The historical evolution and global distribution of column ozone and the amount of tropospheric aerosols are reasonably simulated in the model based on the Representative Concentration Pathways' (RCP) historical emissions of these precursors. The simulated distributions of the terrestrial and marine biogeochemistry parameters agree with recent observations, which is encouraging to use the model for future global change projections.
Uncertainty in climate change projections of discharge for the Mekong River Basin
Authors: Kingston D. G. , Thompson J. R. , Kite G.
Published: May 2011

Abstract. The Mekong River Basin is a key regional resource in Southeast Asia for sectors that include agriculture, fisheries and electricity production. Here we explore the potential impacts of climate change on freshwater resources within the river basin. We quantify uncertainty in these projections associated with GCM structure and climate sensitivity, as well as from hydrological model parameter specification. This is achieved by running pattern-scaled GCM scenarios through a semi-distributed hydrological model (SLURP) of the basin. Pattern-scaling allows investigation of specific thresholds of global climate change including the postulated 2 °C threshold of "dangerous" climate change. Impacts of a 2 °C rise in global mean temperature are investigated using seven different GCMs, providing an implicit analysis of uncertainty associated with GCM structure. Analysis of progressive changes in global mean temperature from 0.5 to 6 °C above the 1961–1990 baseline (using the HadCM3 GCM) reveals a relatively small but non-linear response of annual river discharge to increasing global mean temperature, ranging from a 5.4 % decrease to 4.5 % increase. Changes in mean monthly river discharge are greater (from −16 % to +55 %, with greatest decreases in July and August, greatest increases in May and June) and result from complex and contrasting intra-basin changes in precipitation, evaporation and snow storage/melt. Whilst overall results are highly GCM dependent (in both direction and magnitude), this uncertainty is primarily driven by differences in GCM projections of future precipitation. In contrast, there is strong consistency between GCMs in terms of both increased potential evapotranspiration and a shift to an earlier and less substantial snowmelt season. Indeed, in the upper Mekong (Lancang sub-basin), the temperature-related signal in discharge is strong enough to overwhelm the precipitation-related uncertainty in the direction of change in discharge, with scenarios from all GCMs leading to increased river flow from April–June and decreased flow from July–August.
Effects of seasonality on the distribution of hydrological extremes
Authors: Allamano P. , Laio F. , Claps P.
Published: May 2011

Abstract. This paper focuses on the seasonality of hydroclimatic extremes and on the problem of accounting for their non-homogeneous character in determining the design value. To this aim we devise a simple stochastic world in which extremes are produced by a non-homogeneous extreme value generation process. The design values are estimated in closed analytical form both in a peak over threshold framework and by using the standard annual maxima approach. In this completely controlled world of generated hydrological extremes, a statistical measure of the error associated to the adoption of a homogeneous model is introduced. The sensitivity of this measure, assumed in terms of return period ratio, to the typology and strength of seasonality is investigated. We find that seasonality induces a downward bias in design value estimators. The magnitude of the bias may be large when the peak over threshold approach is adopted, while the return period distortion is limited when the annual maxima are considered. An application to a prealpine to alpine transition region located in North-Western Italy is presented to better clarify the effects of disregarding seasonality in a real case.
Potential and limitations of using soil mapping information to understand landscape hydrology
Authors: Terribile F. , Coppola A. , Langella G. , Martina M. , Basile A.
Published: May 2011

Abstract. The role of soil properties and their spatial distribution in the landscape are already recognised as crucial issues greatly affecting rainfall-runoff dynamics and hence landscape hydrology. This becomes even more important when hydrological monitoring data are lacking. This applies to the critical issue of making hydrological predictions for ungauged basins. The rapid development of hydropedology along with Digital Soil Mapping (DSM) is promising to both enhance our understanding and (spatial) prediction capacity of rainfall-runoff processes and to be a powerful tool for environmental policy research. Despite these developments and broad conceptualizations, the crucial point as to how the soil data from typically available soil mapping databases can be usefully employed by the hydrologist has yet to be addressed. This question implies detailed knowledge of the quality and quantity of information embedded in and behind a soil map. This work produced an analytical evaluation of the potential and limitations of soil data obtained through soil surveys and soil mapping. This evaluation is made from a landscape hydrology viewpoint and is also developed through the following Italian case studies: irrigation management at the district scale, assessment of groundwater vulnerability, flood peak forecasting, and land evaluation for maize production. We show that special care is required in handling soil database data if their full potential is to be achieved. Further, all the case studies agree on the appropriate degree of complexity of the soil hydrological model to be applied. We also emphasise that effective interaction between pedology and hydrology to address landscape hydrology requires (i) better awareness of the hydrologic community about the type of soil information behind a soil map or soil database, (ii) the development by the pedological community of a better quantitative framework for evaluating surveyed hydrological features, and (iii) quantitative information on soil spatial variability and, if possible, on the spatial distribution of prediction errors.
Efficacy and Safety of COX-2 Inhibitors in the Clinical Management of Arthritis: Mini Review
Authors: Mathew Sam T. , Devi S Gayathri , Prasanth V. V. , Vinod B.
Published: May 2011

In the clinical management of arthritis, the choice of nonsteroidal anti inflammatory drug (NSAID) remains confusing and controversial. A common practice on the choice of NSAID in clinical management of arthritis is the risk benefit ratio. The main objective of this review is to addresses the main arguments for the pharmacological and clinical use of COX-2 inhibitors in relation to nonselective NSAIDs for the clinical management of arthritis. This review concluded that, both NSAIDs and COX-2 inhibitors are equally effective and are associated with increased risk of GI, renal, and CV, adverse effects. Complete understanding of the patient's comorbid conditions and concomitant medications, coupled with precise monitoring during the treatment, may help to decrease the threat of adverse effects induced by nonselective NSAIDs and selective COX-2 inhibitors.
Fundamental Solution in the Theory of Thermomicrostretch Elastic Diffusive Solids
Authors: Kumar Rajneesh , Kansal Tarun
Published: May 2011

We construct the fundamental solution of system of differential equations in the theory of thermomicrostretch elastic diffusive solids in case of steady oscillations in terms of elementary functions. Some basic properties of the fundamental solution are established. Some special cases are also discussed.
A Comparison of the Cell Compatibility of Poly(ethyleneimine) with that of other Cationic Biopolymers Used in Applications at Biointerfaces
Authors: Heurich Erik , Zankovych Sergiy , Beyer Markus , Schnabelrauch Matthias , Berg Albrecht , Jandt Klaus D.
Published: May 2011

Poly(ethyleneimine) (PEI) is used as an initiating base layer or intermediate layer for layer‐by‐layer (LBL) technology. Since PEI is potentially cytotoxic in solution, it is necessary to investigate the influence of the physical properties of PEI layers on osteoblast cells. Therefore, the first aim of this study was to test the hypothesis that there is no statistically significant difference of cell adhesion, proliferation, and viability in response to nanometer thin polymer layers of PEI compared to other well‐known polymers. The second aim of this study was to test the hypothesis that the amine‐substituted dextran (aminodextran (AMD)) adheres well on Ti and can be used as a polymer coating in biomaterials applications. Titanium samples were coated with PEI, poly‐L‐lysine (PLL), or AMD using dip coating. The polymer films were investigated with ellipsometry, atomic force microscopy, contact angle measurements, and X‐ray‐photoelectron spectroscopy (XPS). Cell adhesion, proliferation, and viability tests were carried out using osteoblast‐like cells (CAL‐72). Thin polymer layers below 10 nm layer thickness were found on the Ti surfaces. It was shown for the first time that base layers of PEI with nanometer thickness do not affect the bone cell reaction negatively. PEI, therefore, can be used as a functional base layer for LBL functionalization of metallic implants. AMD can be used in biomedical applications but does not adhere on titanium without an adhesion promoter.
Wafer‐Scale Fabrication of Ordered Binary Colloidal Monolayers with Adjustable Stoichiometries
Authors: Vogel Nicolas , de Viguerie Laurence , Jonas Ulrich , Weiss Clemens K. , Landfester Katharina
Published: May 2011

Colloidal monolayers with high order and increased complexity beyond plain hexagonal packing geometries are useful for 2D templating of surface nanostructures and lithographic applications. Here, binary colloidal monolayers featuring a close‐packed monolayer of large spheres (L) with a superlattice of small particles (S) are prepared in a single step using a Langmuir trough. Adjustment of the stoichiometry of the two particle types at the air–water interface leads to a high degree of control over the occupation of the interstitial sites in the close‐packed layer of large spheres by the small colloids. Thus, large areas of binary 2D crystals with LS2, LS6, and LS9 structures are fabricated in a controlled way. The process allows the formation of binary crystals over a wide range of particle size ratios from 0.19 to 0.40. The pH value of the subphase can be used to enhance the crystallization process by changing the contact angle of the particles at the interface. An interfacial polymerization of butyl cyanoacrylate is used to directly image the contact angle of the colloids at the interface. Transfer to solid substrates is achieved by a surface lowering technique. A variety of substrates with arbitrary topographies can thus be decorated with colloidal monolayers. Applied to a lithographic process, such monolayer architectures allow the generation of complex patterns, not accessible with conventional close‐packed monolayers.
Microfluidic Chips for Point‐of‐Care Immunodiagnostics
Authors: Gervais Luc , de Rooij Nico , Delamarche Emmanuel
Published: May 2011

We might be at the turning point where research in microfluidics undertaken in academia and industrial research laboratories, and substantially sponsored by public grants, may provide a range of portable and networked diagnostic devices. In this Progress Report, an overview on microfluidic devices that may become the next generation of point‐of‐care (POC) diagnostics is provided. First, we describe gaps and opportunities in medical diagnostics and how microfluidics can address these gaps using the example of immunodiagnostics. Next, we conceptualize how different technologies are converging into working microfluidic POC diagnostics devices. Technologies are explained from the perspective of sample interaction with components of a device. Specifically, we detail materials, surface treatment, sample processing, microfluidic elements (such as valves, pumps, and mixers), receptors, and analytes in the light of various biosensing concepts. Finally, we discuss the integration of components into accurate and reliable devices.
A general compartment‐based population balance model for particle coating and layered granulation
Authors: Li Jianfeng , Freireich Ben , Wassgren Carl , Litster James D.
Published: May 2011

In this work, a general multidimensional population balance (PB) model is developed to predict the coating volume distribution on polydisperse particles as a function of time during particle coating in a paddle mixer. The model adopts a compartmental approach to account for coating variation caused by particle flow heterogeneity. Simulations show that for a realistic range of seed particle size polydispersity and coating mass applied, the coating volume distribution depends on the growth rate exponent and seed particle size distribute on, with the coating volume coefficient of variance (CoV) approaching an asymptotic value as the coating‐to‐particle volume ratio increases. These effects cannot be predicted by simpler one‐dimensional models. However, the full two‐dimensional PB and simpler one‐dimensional models such as Mann's equation do predict similar sensitivity of coating volume CoV to the variation in the compartment model parameters, i.e., to changes in the particle mixing behavior in the vessel. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Influence of slow diffusing species on mixture diffusion of hexane isomers in silicalite: Characterization by a new cyclic method
Authors: Lettat Kader , Jolimaitre Elsa , Tayakout Mélaz , Tondeur Daniel
Published: May 2011

The feasibility of mono‐ and di‐branched paraffins separation on silicalite was evaluated by performing cyclic breakthrough experiments in liquid phase with mixtures of 2‐methylpentane (2MP), 3‐methylpentane (3MP), 2,3‐dimethylbutane (23DMB), and 2,2‐dimethylbutane (22DMB). For mixtures of the faster diffusing species (2MP, 3MP, and 23DMB), cyclic steady state is obtained from the first cycle. On the other hand, when the slow diffusing species 22DMB is involved, a slow accumulation occurs from cycle to cycle, yielding a change of the breakthrough curves for all the species. Using a diffusion model especially adapted to adsorbent saturation loading, the kinetic and thermodynamic parameters of 22DMB were estimated. Influence of the cycling conditions on the separation performance were finally studied by simulation. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Settling of particles in liquids: Effects of material properties
Authors: Dong K. J. , Yang R. Y. , Zou R. P. , Yu A. B.
Published: May 2011

This article presents a numerical study on the settling of uniform spheres in liquids by means of the discrete element method. The effects of particle and liquid properties, such as particle size, Hamaker constant, liquid density, and viscosity, on the formation of packed beds or cakes were studied in terms of packing fraction, radial distribution function (RDF), and coordination number (CN). The results showed that the packing fraction of a cake increases with increasing particle size but decreases with increasing the Hamaker constant, liquid density, and viscosity. RDF and CN also change correspondingly: packings with lower packing fraction generally have RDFs with fewer peaks and smaller mean CNs. A good correlation between packing fraction and other structural properties was identified. The analysis of the particle‐particle and liquid‐particle interactions showed that the packing properties are mainly affected by the ratio of the interparticle cohesion to the effective gravity of particles. The previously proposed equation linking packing fraction with the interparticle forces has been extended to incorporate the impact‐induced pressure force in a settling process. Based on the modified equation, the effects of key variables on the relationship between packing fraction and particle size were re‐examined for general application. © 2011 American Institute of Chemical Engineers AIChE J, 2012.
A novel 800 kb microduplication of chromosome 16q22.1 resulting in learning disability and epilepsy may explain phenotypic variability in a family with 15q13 microdeletion
Authors: Banka Siddharth , Fitzgibbon Gregory J. , Gaunt Lorraine , Rankin Wendy J. , Clayton‐Smith Jill
Published: May 2011

The phenotype of 15q13.3 microdeletion is variable and can be non‐penetrant. Recently, “second‐hit hypothesis” has been proposed as a possible explanation for some variability in recurrent microdeletion syndromes. We present a family with a 1.9 Mb 15q13.3 deletion and a novel 800 kb 16q22.1duplication. We show that the 16q22.1 duplication may be a phenotypic modifier in this family and likely results in epilepsy and learning difficulties. We state the possible genes in this region that may be important in neurological development and function. © 2011 Wiley‐Liss, Inc.
Understanding physicians' attitudes toward people with Down syndrome
Authors: Pace Jill E. , Shin Mikyong , Rasmussen Sonja A.
Published: May 2011

Understanding attitudes of physicians toward people with Down syndrome is important because of the influence physicians have on the future of individuals with Down syndrome. However, few previous studies have assessed these attitudes. Using data from the 2008 DocStyles© survey, an annual online survey conducted in the United States, we assessed attitudes of physicians toward people with Down syndrome using a survey that included questions about opinions toward inclusive educational settings and workplaces, previous relationships with people with Down syndrome, and comfort in providing them with medical care. Approximately 20% of participants agreed that students with Down syndrome should go to special schools, and nearly a quarter agreed that including students with Down syndrome in regular classrooms is distracting. While 76.0% of respondents felt comfortable providing medical care to people with Down syndrome, 9.8% reported feeling uncomfortable, and 14.3% reported feeling neutral. Results showed that attitudes that supported inclusion and comfort with providing medical care were more commonly reported among non‐Hispanic white physicians, those who had previous relationships with people with Down syndrome, pediatricians, and physicians working in a group or hospital setting. These data are helpful to guide the development of training materials and curricula for healthcare providers regarding Down syndrome. Published 2011 Wiley‐Liss, Inc.
Das hydratisierte Elektron – eine scheinbar vertraute transiente Spezies in chemischen und biologischen Systemen
Authors: Siefermann Katrin R. , Abel Bernd
Published: May 2011

Seit der Entdeckung des solvatisierten Elektrons in Wasser im Jahre 1962 war es Gegenstand intensiver Forschung, aber auch zahlreicher Spekulationen. Über mehrere Jahrzehnte blieben grundlegende Eigenschaften dieser vermeintlich einfachen, transienten Spezies – wie ihre Struktur, Bindungsmotive, Lebensdauern und Bindungsenergien – unzugänglich. Erst kürzlich wurde mit der Bestimmung der vertikalen Bindungsenergie (VBE) des hydratisierten Elektrons ein weiterer Grundstein gelegt, der zum besseren Verständnis dieser chemisch und biologisch relevanten Spezies essentiell ist. Darüber hinaus wurde ein langlebiges hydratisiertes Elektron an der Oberfläche von flüssigem Wasser entdeckt. In diesem Kurzaufsatz werden die Konsequenzen dieser und weiterer neuer Forschungsergebnisse hinsichtlich der Struktur und Reaktivität hydratisierter Elektronen diskutiert.
A sensitive and regenerable biosensor for organophosphate pesticide based on self‐assembled multilayer film with CdTe as fluorescence probe
Authors: Sun Xiangying , Liu Bin , Xia Kaihao
Published: May 2011

A fluorescence biosensor for organophosphorus pesticides was developed. A pH indicator, CdTe quantum dots, were used as an optical transducer of the inhibition of enzyme by analyte. Through the intervening agency of chitosan, the recognition elements (acetylcholinesterase and CdTe) were immobilized onto the surface of quartz by electrostatic attraction to form a self‐assembled multilayer film. In the absence of pesticide, acetylcholine was biocatalytically hydrolysed to yield acetic acid and choline. The released acid resulted in pH decrease, which was sensed by the immobilized pH indicator (CdTe). In the presence of pesticide, the action of acetylcholine was reduced; the fluorescence intensity of the film changed and was related to the concentration of pesticide. This multilayer film could be used as the biosensor for monocrotophos, with a detection limit of 3.20 × 10−8 mol/L; the sensitivity was 100 times higher than that of CdTe in aqueous solution. The sensor was easily regenerated, and had good stability and selectivity for organophosphorus pesticides. Copyright © 2011 John Wiley & Sons, Ltd.
Fluorescence emission mechanism and fluorescence properties of ternary Tb(III) complex with diphenyl sulphoxide and bipyridine
Authors: Li Wen‐Xian , Zheng Yu‐Shan , Chai Wen‐Juan , Ren Tie , Liu Yu , Li Ying‐Jie , Sun Xiao‐Jun , Xing Gao‐Wa
Published: May 2011

A novel ternary complex, TbL5L′(ClO4)3·3H2O, two binary complexes, TbL7(ClO4)3·3H2O and TbL′3.5(ClO4)3·4H2O has been synthesized (using diphenyl sulphoxide as the first ligand L, bipyridine as the second ligand L′). Their composition was analysed by element analysis, coordination titration, IR spectra and 1H‐NMR, and the fluorescence emission mechanism, fluorescence intensities and phosphorescence spectra were also investigated by comparison. It was shown that the ternary rare‐earth complex showed stronger fluorescence intensities than the binary rare‐earth complexes in such material. The strongest characteristic fluorescence emission intensity of the ternary system was 8.23 times, 3.58 times as strong as that of the binary systems TbL7(ClO4)3·3H2O and TbL′3.5 (ClO4)3·4H2O, respectively. By fluorescence analysis it was found that both diphenyl sulphoxide and bipyridine could sensitize the fluorescence intensities of rare‐earth ions. In particular, in the ternary rare‐earth complex, introduction of bipyridine was of benefit to the fluorescence properties of Tb(III). Copyright © 2011 John Wiley & Sons, Ltd.
Pseudomonas aeruginosa amidase: Aggregation in recombinant Escherichia coli
Authors: Borges Patrícia , Pacheco Rita , Karmali Amin
Published: May 2011

The effect of cultivation parameters such as temperature incubation, IPTG induction and ethanol shock on the production of Pseudomonas aeruginosa amidase (E.C.3.5.1.4) in a recombinant Escherichia coli strain in LB ampicillin culture medium was investigated. The highest yield of soluble amidase, relatively to other proteins, was obtained in the condition at 37°C using 0.40 mM IPTG to induce growth, with ethanol. Our results demonstrate the formation of insoluble aggregates containing amidase, which was biologically active, in all the tested growth conditions. Addition of ethanol at 25°C in the culture medium improved amidase yield, which quantitatively aggregated in a biological active form and exhibited in all conditions an increased specific activity relatively to the soluble form of the enzyme. Non‐denaturing solubilization of the aggregated amidase was successfully achieved using L‐arginine. The aggregates obtained from conditions at 37°C by FTIR analysis demonstrated a lower content of intermolecular interactions which facilitated the solubilization step applying non‐denaturing conditions. The higher interactions exhibited in aggregates obtained at suboptimal conditions compromised the solubilization yield. This work provides an approach for the characterization and solubilization of novel reported biologically active aggregates of this amidase.
The imprint of codons on protein structure
Authors: Deane Charlotte M. , Saunders Rhodri
Published: May 2011

The “central dogma” of biology outlines the unidirectional flow of interpretable data from genetic sequence to protein sequence. This has led to the idea that a protein's structure is dependent only on its amino acid sequence and not its genetic sequence. Recently, however, a more than transient link between the coding genetic sequence and the protein structure has become apparent. The two interact at the ribosome via the process of co‐translational protein folding. Evidence for co‐translational folding is growing rapidly, but the influence of codons on the protein structure attained is still highly contentious. It is theorised that the speed of codon translation modulates the time available for protein folding and hence the protein structure. Here, past and present research regarding synonymous codons and codon translation speed are reviewed within the context of protein structure attainment.
Coupling between codon usage, translation and protein export in Escherichia coli
Authors: Zalucki Yaramah M. , Beacham Ifor R. , Jennings Michael P.
Published: May 2011

Proteins destined for export via the Sec‐dependent pathway are synthesized with a short N‐terminal signal peptide. A requirement for export is that the proteins are in a translocationally competent state. This is a loosely folded state that allows the protein to pass through the SecYEG apparatus and pass into the periplasm. In order to maintain pre‐secretory proteins in an export‐competent state, there are many factors that slow the folding of the pre‐secretory protein in the cytoplasm. These include cytoplasmic chaperones, such as SecB, and the signal recognition particle, which bind the pre‐secretory protein and direct it to the cytoplasmic membrane for export. Recently, evidence has been published that non‐optimal codons in the signal sequence are important for a time‐critical early event to allow the correct folding of pre‐secretory proteins. This review details the recent developments in folding of the signal peptide and the pre‐secretory protein.
First BRET‐based screening assay performed in budding yeast leads to the discovery of CDK5/p25 interaction inhibitors
Authors: Corbel Caroline , Wang Qian , Bousserouel Hadjira , Hamdi Amel , Zhang Bing , Lozach Olivier , Ferandin Yoan , Tan Vincent B. C. , Guéritte Françoise , Colas Pierre , Couturier Cyril , Bach Stéphane
Published: May 2011

The protein kinase CDK5 (cyclin‐dependent kinase 5) is activated through its association with a cyclin‐like protein p35 or p39. In pathological conditions (such as Alzheimer's disease and various other neuropathies), truncation of p35 leads to the appearance of the p25 protein. The interaction of p25 with CDK5 up‐regulates the kinase activity and modifies the substrate specificity. ATP‐mimetic inhibitors of CDK5 have already been developed. However, the lack of selectivity of such inhibitors is often a matter of concern. An alternative approach can be used to identify highly specific inhibitors that disrupt protein interactions involving protein kinases. We have developed a bioluminescence resonance energy transfer (BRET)‐based screening assay in yeast to discover protein–protein interaction inhibitors (P2I2). Here, we present the first use of BRET in yeast for the screening of small molecule libraries. This screening campaign led to the discovery of one molecule that prevents the interaction between CDK5 and p25, thus inhibiting the protein kinase activity. This molecule may give rise to high‐specificity drug candidates.

Accompanying article Zhang et al.
Archaeal‐Bacterial Chimeric RNase P RNAs: Towards Understanding RNA's Architecture, Function and Evolution
Authors: Li Dan , Gößringer Markus , Hartmann Roland K.
Published: May 2011

The higher protein content of archaeal RNase P (1 RNA+4 proteins) compared to the bacterial homologue (1 RNA+1 protein) correlates with a large loss of RNA‐alone activity (i.e., in the absence of protein cofactors). Here we show, for the first time, that a catalytic (C) domain of an archaeal RNase P RNA (P RNA) can functionally replace the Escherichia coli C domain in a chimeric P RNA, to provide the essential RNase P function in E. coli cells. This adaptation was achieved by 1) three minor alterations in the archaeal C domain, 2) restoration of the L9–P1 interdomain contact that is found in bacterial and archaeal type A RNAs, and 3) installation of another interdomain contact (L18–P8) that is present in bacterial but absent in archaeal P RNAs. We conclude 1) that the C domains of bacterial and archaeal P RNAs of type A have been largely conserved since the evolutionary separation of bacteria and archaea, and 2) that the L18–P8 RNA–RNA contact has been replaced with protein–protein contacts in archaeal RNase P. Function of the chimeric P RNA in E. coli required overexpression of the E. coli RNase P protein to increase the RNA's reduced cellular levels; this was attributed to enhanced degradation of the chimeric P RNA.
Prognostic value of cardiac troponin‐I or troponin‐T elevation following nonemergent percutaneous coronary intervention: A meta‐analysis
Authors: Feldman Dmitriy N. , Kim Luke , Rene A. Garvey , Minutello Robert M. , Bergman Geoffrey , Wong S. Chiu
Published: May 2011

Objectives:

The aim of this meta‐analysis was to assess the prevalence and prognostic value regarding mortality of cTnT or cTnI elevations after nonemergent percutaneous coronary intervention (PCI) in a large number of cohort/registry studies.

Background:

Routine cardiac troponin measurement after elective PCI has been controversial among interventionalists. Recent studies have provided conflicting data in regard to predictive value of cardiac troponin‐T (cTnT) and troponin‐I (cTnI) elevation after non‐emergent PCI.

Methods:

Electronic and manual searches were conducted of all published studies reporting on the prognostic impact of cTnT or cTnI elevation after elective PCI. A meta‐analysis was performed with all‐cause mortality at follow‐up as the primary endpoint.

Results:

We identified 22 studies, involving 22,353 patients, published between 1998 and 2009. Postprocedural cTnT and cTnI were elevated in 25.9% and 34.3% of patients, respectively. Follow‐up period ranged from 3 to 67 months (mean: 17.7 ± 14.9 months). The results showed no heterogeneity among the trials (Q‐test: 25.39; I2: 17%; P = 0.23). No publication bias was detected (Egger's test: P = 0.16). The long‐term all‐cause mortality in patients with cTnI or cTnT elevation after PCI (5.8%) was significantly higher when compared to patients without cTnI or cTnT elevation (4.4%); OR 1.45 (95% CI: 1.22–1.72), P < 0.01. In addition, the postprocedural composite adverse clinical events of all‐cause mortality or myocardial infarction (MI) in patients with cTnI or cTnT elevation after PCI (9.2%) was significantly higher when compared to patients without cTnI or cTnT elevation (5.3%); OR 1.77 (95% CI: 1.48–2.11), P < 0.01.

Conclusions:

The current meta‐analysis indicates that cTnI or cTnT elevation after nonemergent PCI is indicative of an increase in long‐term all‐cause mortality as well as the composite adverse events of all‐cause mortality and MI. Efforts to routinely monitor periprocedural cTn levels along with more intensive outpatient monitoring/treatment of patients with cTn elevations may help to improve the long‐term adverse outcomes in these patients following non‐emergent PCI. © 2011 Wiley‐Liss, Inc.
Nano beam diffraction and precession in an energy filtered CS corrected transmission electron microscope
Authors: Benner G. , Niebel H. , Pavia G.
Published: May 2011

Nano beam diffraction is a prerequisite to collecting structural information from particles as small as 1 nm in diameter. We describe here a novel ray path, where the limiting illumination aperture is arranged higher up in the illumination system of a transmission electron microscope (TEM) so that it can be demagnified further. This results in a high flexibility concerning the illuminating field and electron beam convergence angle without any need for readjustments of pivot points and refocusing of the diffraction lens. We show that artifact‐free diffraction patterns can be obtained with diffraction fields down to 20 nm in diameter under genuine parallel illumination conditions. The limitations of the nano beam diffraction mode by physical diffraction effects are discussed. Either the illumination field or the diffraction spots or both may show diffraction fringes as a result of these effects. Zero energy loss filtering of (precession) electron diffraction spot patterns increases their contrast and makes weak diffraction spots visible. A method to acquire (energy filtered precession) electron diffraction spot pattern in a spherical aberration (CS) corrected TEM has been developed and first results are presented. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)