bluuebunny/crossref_metadata_2025 huggingface dataset:
Response of Small Enterprises to the Pressures of ERP Adoption
Authors: Rajendran R. , Elangovan N.
Published: February 2012

Decision to adopt ERP by small enterprises is influenced by external forces due to their dependence on the supply chain. However, certain factors mediate the external forces and alter their influences. This article intends to highlight that the response of small enterprises to the institutional isomorphic pressures in adoption decision of ERP depends on the perception of cost-benefit and the complexity of the organization. A conceptual model was developed and empirically tested by a survey among SMEs of the knitwear garment cluster that has a well developed institutional structure. The mediation effect is tested in SEM software and its significance is verified by bootstrapping. The results show that perceived benefit, challenges and organizational complexity confound the external forces. The study reveals how the small enterprises respond to the external pressures so that stakeholders involved in promotion of ERP can plan a right strategy for encouraging ERP adoption among SMEs.
Inter-Organizational Safety Debate
Authors: Amaldi Paola , Rozzi Simone
Published: February 2012

The management of safety critical operations cannot be left to the initiative of those individuals directly in contact with the production processes. Society as a whole has a role. This paper explores the interface between societal components having a direct active role in the “safety debate”. The reference domain is air traffic management and the interface is among air traffic controllers and pilots – as directly involved in the management of the air traffic – and two agencies, the NTSB (responsible for safety investigation after an accident) and FAA (responsible for regulating, upgrading and training of the workforce). Recent debates in safety management highlight that safe practice is a control problem: the result of effective hierarchical transmissions of safety constraints and making the boundaries of acceptable performance visible. This work analyzes how safety constraints related to an alarm system are represented, transmitted and interpreted by several parties – all committed to safety of operations in air traffic management. A “miscalibration” pattern has emerged where the tendency to ignore the alarm was initially addressed at higher hierarchical levels in relation to alarm design, and only in 2006 was addressed in relation to the core issue of nuisance or false alerts (FA).
HER2/HER3 Signaling Regulates NK Cell-Mediated Cytotoxicity via MHC Class I Chain-Related Molecule A and B Expression in Human Breast Cancer Cell Lines
Authors: Okita Riki , Mougiakakos Dimitrios , Ando Takashi , Mao Yumeng , Sarhan Dhifaf , Wennerberg Erik , Seliger Barbara , Lundqvist Andreas , Mimura Kousaku , Kiessling Rolf
Published: February 2012

Overexpression of the receptor tyrosine kinases HER2 and HER3 is associated with a poor prognosis in several types of cancer. Presently, HER2- as well as HER3-targeted therapies are in clinical practice or evaluated within clinical trials, including treatment with mAbs mediating growth inhibition and/or activation of Ab-induced innate or adaptive cellular immunity. A better understanding of how HER2/HER3 signaling in tumors influences cellular immune mechanisms is therefore warranted. In this study, we demonstrate that HER2/HER3 signaling regulates the expression of MHC class I-related chain A and B (MICA and MICB) in breast cancer cell lines. The MICA and MICB (MICA/B) molecules act as key ligands for the activating receptor NK group 2, member D (NKG2D) and promote NK cell-mediated recognition and cytolysis. Genetic silencing of HER3 but not HER2 downregulated the expression of MICA/B, and HER3 overexpression significantly enhanced MICA expression. Among the major pathways activated by HER2/HER3 signaling, the PI3K/AKT pathway was shown to predominantly regulate MICA/B expression. Treatment with the HER3-specific ligand neuregulin 1β promoted the expression in a process that was antagonized by pharmacological and genetic interference with HER3 but not by the ataxia-telangiectasia–mutated (ATM) and ATM and Rad3-related protein kinases inhibitor caffeine. These observations further emphasize that HER2/HER3 signaling directly, and not via genotoxic stress, regulates MICA/B expression. As anticipated, stimulating HER2/HER3 enhanced the NKG2D-MICA/B–dependent NK cell-mediated cytotoxicity. Taken together, we conclude that signaling via the HER2/HER3 pathway in breast carcinoma cell lines may lead to enhanced NKG2D-MICA/B recognition by NK cells and T cells.
Development of a Detailed Log Booklet for social Ecological Physical Activity Research
Authors: Kaczynski Andrew T.
Published: February 2012

To advance social ecological research, tools are required to better assess the contextual nature of physical activity outcomes. This study describes the development of a detailed log booklet to capture relevant episode-specific data, including location and purpose, about participants’ free-living activity patterns. The log was developed using definitions and questions from existing physical activity questionnaires as well as measures designed to elicit more specific and detailed information relevant to social ecological studies of physical activity. Utility of the log was tested with 580 community residents over seven days. It was found to be practical and feasible for use in community-based physical activity research, and yielded a wealth of episodic information about intensity, duration, location, purpose, and co-participants, among other details.
Impact of a Dietary Supplement Containing 1,3-Dimethylamylamine on Blood Pressure and Bloodborne Markers of Health: A 10-Week Intervention Study
Authors: Whitehead Paul N. , Schilling Brian K. , Farney Tyler M. , Bloomer Richard J.
Published: February 2012

Background

1,3-dimethylamylamine is a commonly used ingredient within dietary supplements. Our prior work with this agent indicates a transient increase in blood pressure (systolic in particular) following oral ingestion of a single dosage, but no significant increase in resting blood pressure following chronic ingestion. Moreover, intervention studies involving both two and eight weeks of treatment with finished products containing 1,3-dimethylamylamine indicate minimal or no change in bloodborne markers of health. The present study sought to extend these findings by using a 10 -week intervention trial to determine the change in selected markers of health in a sample of men.

Methods

25 healthy men were randomly assigned to either a placebo (n = 13) or to a supplement containing 1,3-dimethylamylamine (n = 12) for a period of 10 weeks. Before and after the intervention, resting blood pressure and heart rate were measured, and blood samples were collected for determination of complete blood count, metabolic panel, and lipid panel.

Results

No significant differences were noted between conditions for blood pressure ( P > 0.05), although systolic blood pressure increased approximately 6 mmHg with the supplement (diastolic blood pressure decreased approximately 4 mmHg). A main effect for time was noted for heart rate ( P = 0.016), with values decreasing from pre to post intervention. There were significant main effects for time for creatinine (increased from pre to post intervention; P = 0.043) and alkaline phosphatase (decreased from pre to post intervention; P = 0.009), with no condition differences noted ( P > 0.05). There was a significant interaction noted for low density lipoprotein cholesterol (LDL-C) ( P = 0.043), with values decreasing in the supplement group from pre to post intervention approximately 7 mg · dL-1 ( P = 0.034). No other effects of significance were noted for bloodborne variables.

Conclusion

These data indicate that a dietary supplement containing 1,3-dimethylamylamine does not result in a statistically significant increase in resting heart rate or blood pressure (although systolic blood pressure is increased ~6 mmHg with supplement use). The supplement does not negatively impact bloodborne markers of health. Further study is needed involving a longer intervention period, a larger sample size, and additional measures of health and safety.
Projections of mid-century summer air-quality for North America: effects of changes in climate and precursor emissions
Authors: Kelly J. , Makar P. A. , Plummer D. A.
Published: February 2012

Abstract. Ten year simulations of North American current and future air-quality were carried out using a regional air-quality model driven by a regional climate model, in turn driven by a general circulation model. Three separate summer scenarios were performed: a scenario representing the years 1997 to 2006, and two SRES A2 climate scenarios for the years 2041 to 2050. The first future climate scenario makes use of 2002 anthropogenic precursor emissions, and the second applied emissions scaling factors derived from the IPCC Representative Concentration Pathway 6 (RCP 6) scenario to estimate emissions for 2050 from existing 2020 projections. Ten-year averages of ozone and PM2.5 at North American monitoring network stations were used to evaluate the model's current chemical climatology. The model was found to have a similar performance for ozone as when driven by an operational weather forecast model. The PM2.5 predictions had larger negative biases, likely resulting from the absence of rainwater evaporation, and from sub-regional negative biases in the surface temperature fields, in the version of the climate model used here. The differences between the two future climate simulations and the current climate simulation were used to predict the changes to air-quality that might be expected in a future warmer climate, if anthropogenic precursor emissions remain constant at their current levels, versus if the RCP 6 emissions controls were adopted. Metrics of concentration, human health, and ecosystem damage were compared for the simulations. The scenario with future climate and current anthropogenic emissions resulted in worse air-quality than for current conditions – that is, the effect of climate-change alone, all other factors being similar, would be a worsening of air-quality. These effects are spatially inhomogeneous, with the magnitude and sign of the changes varying with region. The scenario with future climate and RCP 6 emissions for 2050 resulted in an improved air-quality, with decreases in key pollutant concentrations, in acute human mortality associated with air-pollution, and in sulphur and ozone deposition to the ecosystem. The positive outcomes of the RCP 6 emissions reductions were found to be of greater magnitude than the negative outcomes of climate change alone. The RCP 6 scenario however resulted in an increase in the deposition of nitrogen, as a result of increased ammonia emissions expected in that scenario, compared to current ammonia emissions levels. The results of the study raise the possibility that simultaneous reductions of greenhouse gases and air pollution precursors may further reduce air pollution levels, with the added benefits of an immediate reduction in the impacts of air pollution on human and ecosystem health. Further scenarios to investigate this possibility are therefore recommended.
Tropospheric methanol observations from space: retrieval evaluation and constraints on the seasonality of biogenic emissions
Authors: Wells K. C. , Millet D. B. , Hu L. , Cady-Pereira K. E. , Xiao Y. , Shephard M. W. , Clerbaux C. L. , Clarisse L. , Coheur P.-F. , Apel E. C. , de Gouw J. , Warneke C. , Singh H. B. , Goldstein A. H. , Sive B. C.
Published: February 2012

Abstract. Methanol retrievals from nadir-viewing space-based sensors offer powerful new information for quantifying methanol emissions on a global scale. Here we apply an ensemble of aircraft observations over North America to evaluate new methanol measurements from the Tropospheric Emission Spectrometer (TES) on the Aura satellite, and combine the TES data with observations from the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp-A satellite to investigate the seasonality of methanol emissions from northern midlatitude ecosystems. Using the GEOS-Chem chemical transport model as an intercomparison platform, we find that the TES retrieval performs well when the degrees of freedom for signal (DOFS) are above 0.5, in which case the model : TES regressions are generally consistent with the model : aircraft comparisons. Including retrievals with DOFS below 0.5 degrades the comparisons, as these are excessively influenced by the a priori. The comparisons suggest DOFS > 0.5 as a minimum threshold for interpreting retrievals of trace gases with a weak tropospheric signal. We analyze one full year of satellite observations and find that GEOS-Chem, driven with MEGANv2.1 biogenic emissions, underestimates observed methanol concentrations throughout the midlatitudes in springtime, with the timing of the seasonal peak in model emissions 1–2 months too late. We attribute this discrepancy to an underestimate of emissions from new leaves in MEGAN, and apply the satellite data to better quantify the seasonal change in methanol emissions for midlatitude ecosystems. The derived parameters (relative emission factors of 11.0, 1.0, 0.05 and 8.6 for new, growing, mature, and old leaves, respectively, plus a leaf area index activity factor of 0.75 for expanding canopies with leaf area index < 2.0) provide a more realistic simulation of seasonal methanol concentrations in midlatitudes on the basis of IASI, TES, and ground-based measurements.
Retrieval of aerosol optical depth over land based on a time series technique using MSG/SERIVI data
Authors: Mei L. , Xue Y. , de Leeuw G. , Holzer-Popp T. , Guang J. , Li Y. , Yang L. , Xu H. , Xu X. , Li C. , Wang Y. , Wu C. , Hou T. , He X. , Liu J. , Dong J. , Chen Z.
Published: February 2012

Abstract. A novel approach for the joint retrieval of aerosol optical depth (AOD) and surface reflectance, using Meteosat Second Generation – Spinning Enhanced Visible and Infrared Imagers (MSG/SEVIRI) observations in two solar channels, is presented. The retrieval is based on a time series (TS) technique, which makes use of the two visible bands at 0.6 μm and 0.8 μm in three orderly scan times (15 min interval between two scans) to retrieve the AOD over land. Using the radiative transfer equation for plane-parallel atmospheres two coupled differential equations for the upward and downward fluxes are derived. The boundary conditions for the upward and downward fluxes at the top and at the bottom of the atmosphere are used in these equations to provide an analytic solution for the surface reflectance. To derive these fluxes, the aerosol single scattering albedo (SSA) and asymmetry factor are required to provide a solution. These are provided from a set of six pre-defined aerosol types with the SSA and asymmetry factor (g). We assume one aerosol type for a grid of 1° × 1° and the surface reflectance changes little between two consequent scans. A k approximation was used in the inversion to find the best solution of atmospheric properties and surface reflectance. The algorithm makes use of numerical minimisation routines to obtain the optimal solution of atmospheric properties and surface reflectance by selection of the most suitable aerosol type from pre-defined sets. Also, it is assumed that the surface reflectance is little influenced by aerosol scattering at 1.6 μm and therefore the ratio of surface reflectances in the solar band for two consequent scans can be well-approximated by the ratio of the reflectances at 1.6 μm. A further assumption is that the surface reflectance varies only slightly over a period of 30 min. A detailed analysis of the retrieval results show that it is suitable for AOD retrieval over land. Six Aerosol Robotic Network (AERONET) sites with different surface types were used for detailed analysis and 42 other AERONET sites were used for validation. From 445 collocations representing stable and homogeneous aerosol type, we found that >75% of MSG-retrieved AOD values compared to AERONET observed values with an error envelope of ±0.05 ± 0.15τ and a high correlation (R > 0.86). The AOD datasets derived using the TS method with SEVIRI data was also compared with collocated AOD products derived from the NASA TERRA and AQUA MODIS data using the dark dense vegetation (DDV) method and the Deep Blue algorithms. Using the TS method, AOD could be retrieved for more pixels than with the NASA Deep Blue algorithm. The AOD values derived compare favourably.
Polar cap arcs from the magnetosphere to the ionosphere: kinetic modelling and observations by Cluster and TIMED
Authors: Maggiolo R. , Echim M. , Simon Wedlund C. , Zhang Y. , Fontaine D. , Lointier G. , Trotignon J.-G.
Published: February 2012

Abstract. On 1 April 2004 the GUVI imager onboard the TIMED spacecraft spots an isolated and elongated polar cap arc. About 20 min later, the Cluster satellites detect an isolated upflowing ion beam above the polar cap. Cluster observations show that the ions are accelerated upward by a quasi-stationary electric field. The field-aligned potential drop is estimated to about 700 V and the upflowing ions are accompanied by a tenuous population of isotropic protons with a temperature of about 500 eV. The magnetic footpoints of the ion outflows observed by Cluster are situated in the prolongation of the polar cap arc observed by TIMED GUVI. The upflowing ion beam and the polar cap arc may be different signatures of the same phenomenon, as suggested by a recent statistical study of polar cap ion beams using Cluster data. We use Cluster observations at high altitude as input to a quasi-stationary magnetosphere-ionosphere (MI) coupling model. Using a Knight-type current-voltage relationship and the current continuity at the topside ionosphere, the model computes the energy spectrum of precipitating electrons at the top of the ionosphere corresponding to the generator electric field observed by Cluster. The MI coupling model provides a field-aligned potential drop in agreement with Cluster observations of upflowing ions and a spatial scale of the polar cap arc consistent with the optical observations by TIMED. The computed energy spectrum of the precipitating electrons is used as input to the Trans4 ionospheric transport code. This 1-D model, based on Boltzmann's kinetic formalism, takes into account ionospheric processes such as photoionization and electron/proton precipitation, and computes the optical and UV emissions due to precipitating electrons. The emission rates provided by the Trans4 code are compared to the optical observations by TIMED. They are similar in size and intensity. Data and modelling results are consistent with the scenario of quasi-static acceleration of electrons that generate a polar cap arc as they precipitate in the ionosphere. The detailed observations of the acceleration region by Cluster and the large scale image of the polar cap arc provided by TIMED are two different features of the same phenomenon. Combined together, they bring new light on the configuration of the high-latitude magnetosphere during prolonged periods of Northward IMF. Possible implications of the modelling results for optical observations of polar cap arcs are also discussed.
Spectral energy transfer of atmospheric gravity waves through sum and difference nonlinear interactions
Authors: Huang K. M. , Liu A. Z. , Zhang S. D. , Yi F. , Li Z.
Published: February 2012

Abstract. Nonlinear interactions of gravity waves are studied with a two-dimensional, fully nonlinear model. The energy exchanges among resonant and near-resonant triads are examined in order to understand the spectral energy transfer through interactions. The results show that in both resonant and near-resonant interactions, the energy exchange between two high frequency waves is strong, but the energy transfer from large to small vertical scale waves is rather weak. This suggests that the energy cascade toward large vertical wavenumbers through nonlinear interaction is inefficient, which is different from the rapid turbulence cascade. Because of considerable energy exchange, nonlinear interactions can effectively spread high frequency spectrum, and play a significant role in limiting wave amplitude growth and transferring energy into higher altitudes. In resonant interaction, the interacting waves obey the resonant matching conditions, and resonant excitation is reversible, while near-resonant excitation is not so. Although near-resonant interaction shows the complexity of match relation, numerical experiments show an interesting result that when sum and difference near-resonant interactions occur between high and low frequency waves, the wave vectors tend to approximately match in horizontal direction, and the frequency of the excited waves is also close to the matching value.
Dissolved organic carbon release by marine macrophytes
Authors: Barrón C. , Apostolaki E. T. , Duarte C. M.
Published: February 2012

Abstract. Estimates of dissolved organic carbon (DOC) release by marine macrophyte communities (seagrass meadows and macroalgal beds) were obtained experimentally using in situ benthic chambers. The effect of light availability on DOC release by macrophyte communities was examined in two communities both by comparing net DOC release under light and dark, and by examining the response of net DOC release to longer-term (days) experimental shading of the communities. All most 85% of the seagrass communities and almost all of macroalgal communities examined acted as net sources of DOC. There was a weak tendency for higher DOC fluxes under light than under dark conditions in seagrass meadow. There is no relationship between net DOC fluxes and gross primary production (GPP) and net community production (NCP), however, this relationship is positive between net DOC fluxes and community respiration. Net DOC fluxes were not affected by shading of a T. testudinum community in Florida for 5 days, however, shading of a mixed seagrass meadow in the Philippines led to a significant reduction on the net DOC release when shading was maintained for 6 days compared to only 2 days of shading. Based on published and unpublished results we also estimate the global net DOC production by marine macrophytes. The estimated global net DOC flux, and hence export, from marine macrophyte is about 0.197 ± 0.015 Pg C yr−1 or 0.212 ± 0.016 Pg C yr−1 depending if net DOC flux by seagrass meadows was estimated by taking into account the low or high global seagrass area, respectively.
Hydrological response of a small catchment burned by experimental fire
Authors: Stoof C. R. , Vervoort R. W. , Iwema J. , van den Elsen E. , Ferreira A. J. D. , Ritsema C. J.
Published: February 2012

Abstract. Fire can considerably change hydrological processes, increasing the risk of extreme flooding and erosion events. Although hydrological processes are largely affected by scale, catchment-scale studies on the hydrological impact of fire in Europe are scarce, and nested approaches are rarely used. We performed a catchment-scale experimental fire to improve insight into the drivers of fire impact on hydrology. In north-central Portugal, rainfall, canopy interception, streamflow and soil moisture were monitored in small shrub-covered paired catchments pre- and post-fire. The shrub cover was medium dense to dense (44 to 84%) and pre-fire canopy interception was on average 48.7% of total rainfall. Fire increased streamflow volumes 1.6 times more than predicted, resulting in increased runoff coefficients and changed rainfall-streamflow relationships – although the increase in streamflow per unit rainfall was only significant at the subcatchment-scale. Fire also fastened the response of topsoil moisture to rainfall from 2.7 to 2.1 h (p = 0.058), and caused more rapid drying of topsoils after rain events. Since soil physical changes due to fire were not apparent, we suggest that changes resulting from vegetation removal played an important role in increasing streamflow after fire. Results stress that fire impact on hydrology is largely affected by scale, highlight the hydrological impact of fire on small scales, and emphasize the risk of overestimating fire impact when upscaling plot-scale studies to the catchment-scale. Finally, they increase understanding of the processes contributing to post-fire flooding and erosion events.
Effects of climate model radiation, humidity and wind estimates on hydrological simulations
Authors: Haddeland I. , Heinke J. , Voß F. , Eisner S. , Chen C. , Hagemann S. , Ludwig F.
Published: February 2012

Abstract. Due to biases in the output of climate models, a bias correction is often needed to make the output suitable for use in hydrological simulations. In most cases only the temperature and precipitation values are bias corrected. However, often there are also biases in other variables such as radiation, humidity and wind speed. In this study we tested to what extent it is also needed to bias correct these variables. Responses to radiation, humidity and wind estimates from two climate models for four large-scale hydrological models are analysed. For the period 1971–2000 these hydrological simulations are compared to simulations using meteorological data based on observations and reanalysis; i.e. the baseline simulation. In both forcing datasets originating from climate models precipitation and temperature are bias corrected to the baseline forcing dataset. Hence, it is only effects of radiation, humidity and wind estimates that are tested here. The direct use of climate model outputs result in substantial different evapotranspiration and runoff estimates, when compared to the baseline simulations. A simple bias correction method is implemented and tested by rerunning the hydrological models using bias corrected radiation, humidity and wind values. The results indicate that bias correction can successfully be used to match the baseline simulations. Finally, historical (1971–2000) and future (2071–2100) model simulations resulting from using bias corrected forcings are compared to the results using non-bias corrected forcings. The relative changes in simulated evapotranspiration and runoff are relatively similar for the bias corrected and non bias corrected hydrological projections, although the absolute evapotranspiration and runoff numbers are often very different. The simulated relative and absolute differences when using bias corrected and non bias corrected climate model radiation, humidity and wind values are, however, smaller than literature reported differences resulting from using bias corrected and non bias corrected climate model precipitation and temperature values.
Addressing secondary students' naïve ideas about freshwater springs in order to develop an instructional tool to promote conceptual reconstruction
Authors: Reinfried S. , Tempelmann S. , Aeschbacher U.
Published: February 2012

Abstract. "Water knowledge" has now become a socio-political and future-orientated necessity. Erroneous notions or preconceptions of hydrology can have a deleterious effect on our understanding of the scientific facts and their interrelations that are of relevance to sustainable water management. This explorative pilot study shows that erroneous and naïve ideas about the origin of freshwater springs are common at the lower secondary level. The purpose of this study was two-fold: (1) to investigate the nature of misconceptions about freshwater springs among 13-year-old students, and (2) to develop an efficient instructional tool that promotes conceptual reconstruction in the learners' minds. To assess students' naïve ideas we conducted interviews, examined student work, and asked students to fill in a questionnaire. The identified naïve ideas were used to construct an instructional tool based on the findings of learning psychology aiming at promoting deep learning, thus facilitating a lasting conceptual reconstruction of the concept of freshwater springs.
On the Shelf Resonances of the Gulf of Carpentaria and the Arafura Sea
Authors: Webb D. J.
Published: February 2012

Abstract. A numerical model is used to investigate the resonances of the Gulf of Carpentaria and the Arafura Sea. The model is forced at the shelf edge, first with physically realistic real values of angular velocity. The response functions at points within the region show maxima and other behaviour which imply that resonances are involved but it is difficult to be more specific. The study is then extended to complex angular velocities and the results then show a clear pattern of gravity wave and Rossby wave like resonances. The properties of the resonances are investigated and used to reinterpret the responses at real values of angular velocity. It is found that in some regions the response is dominated by modes trapped between the shelf edge and the coast or between opposing coastlines. In other regions the resonances show cooperative behaviour, possibly indicating the importance of other physical processes.
Influence of sea ice lead-width distribution on turbulent heat transfer between the ocean and the atmosphere
Authors: Marcq S. , Weiss J.
Published: February 2012

Abstract. Leads are linear-like structures of open water within the sea ice cover that develop as the result of fracturing due to divergence or shear. Through leads, air and water come into contact and directly exchange latent and sensible heat through convective processes driven by the large temperature and moisture differences between them. In the central Arctic, leads only cover 1 to 2% of the ocean during winter, but account for more than 70% of the upward heat fluxes. Furthermore, narrow leads (several meters) are more than twice as efficient at transmitting turbulent heat than larger ones (several hundreds of meters). We show that lead widths are power law distributed, P(X)~X−a with a>1, down to very small spatial scales (20 m or below). This implies that the open water fraction is by far dominated by very small leads. Using two classical formulations, which provide first order turbulence closure for the fetch-dependence of heat fluxes, we find that the mean heat fluxes (sensible and latent) over open water are up to 55% larger when considering the lead-width distribution obtained from a SPOT satellite image of the ice cover, compared to the situation where the open water fraction constitutes one unique large lead and the rest of the area is covered by ice, as it is usually considered in climate models at the grid scale. This difference may be even larger if we assume that the power law scaling of lead widths extends down to smaller (~1 m) scales. Such estimations may be a first step towards a subgrid scale parameterization of the spatial distribution of open water for heat fluxes calculations in ocean/sea ice coupled models.
Characterization and Chondrogenic Differentiation of Menstrual Blood-Derived Stem Cells on a Nanofibrous Scaffold
Authors: Kazemnejad Somaieh , Akhondi Mohammad-Mehdi , Soleimani Masoud , Zarnani Amir Hassan , Khanmohammadi Manijeh , Darzi Saeedeh , Alimoghadam Kamran
Published: February 2012

Introduction

The recent identification of menstrual blood-derived stem cells (MenSCs) as a unique population of stem cells has created enormous promise for tissue engineering. In this study, after characterization of MenSCs in comparison with bone marrow-derived stem cells (BMSCs), the potential of MenSCs seeded into electrospun, biodegradable, nanofibrous scaffolds in order to engineer cartilage was evaluated.

Methods

MenSCs and BMSCs were isolated by discontinuous density gradient centrifugation and plastic adherence. After characterization of MenSCs compared with BMSCs, MenSC differentiation into chondrocytes was investigated on a nanofibrous scaffold with specific growth and differentiation factors. The scaffold was prepared from polycaprolactone (PCL) and its surface was modified by plasma treatment.

Results

Flow cytometric analysis of expanded cells showed that MenSCs typically express some surface and intracellular markers associated with BMSCs. But marked expression of OCT-4 and the absence of STRO1 distinguished them from mesenchymal stem cells obtained from bone marrow. Based on scanning electron microscope images, the MenSCs were strongly anchored to the highly porous scaffold, which they penetrated and proliferated on. The scaffold contained an extensive cartilage-like extracellular matrix with about 50% greater glycosaminoglycan content than control MenSCs differentiated in a two-dimensional (2D) culture system (p<0.05). Considerable amounts of proteoglycan were produced by the cells differentiated on the scaffold, as demonstrated by Alcian blue staining. Unlike undifferentiated MenSCs, cells differentiated on the scaffold had strong immunoreactivity with monoclonal antibody against collagen type II.

Conclusions

The evidence presented in this study introduces MenSCs as a suitable stem cell population candidate for cartilage tissue engineering.
Luminescence and Morphological Kinetics of Functionalized ZnS Colloidal Nanocrystals
Authors: Sana Prabha , Hashmi Lubna , Malik M. M.
Published: February 2012

This paper reports functionalized zinc sulphide (ZnS) semiconductor nanocrystals (quantum dots, approx., 2.5 nm) which are an important building block in self-assembled nanostructures. ZnS is functionalized by organic stabilizer Thio glycolic acid (TGA). The samples have been synthesized by colloidal technique at relatively low temperature (below 100°C) at an atmospheric pressure of 10−3 torr. Manganese (Mn) doping ions have been incorporated (doped) in ZnS host lattice and observed its effect on growth morphology and optical properties of ZnS colloidal nanocrystals. By XRD, SEM, TEM, and PL, the obtained cubic phase nanosized TGA-capped ZnS materials were characterized. The morphology of ZnS obtained at different temperatures are analyzed by SEM. The crystallite size of the ZnS nanoparticles was estimated from the X-ray diffraction pattern by using Scherrer’s formula (approximately 2.5 nm) which is confirmed by TEM. The estimated bandgap value of ZnS NC’s by ()2 versus
plot was 4.89 eV. Gaussian fitting curve in photoluminescence (PL) spectra indicated room temperature emission wavelength range from 300 to 500 nm in undoped and Mn-doped ZnS, with different emission peak intensities, and suggested the wide band emission colours in visible and near UV region which has wider applications in optical devices.
Use of Functionalized Resin for Matrix Separation and Trace Elements Determination in Petroleum Produced Formation Water by
Inductively Coupled Plasma Mass Spectrometry
Authors: Santelli Ricardo Erthal , Freire Aline Soares , Oliveira Eliane Padua , Lemos Valfredo Azevedo , Novaes Cléber Galvão , Bezerra Marcos Almeida
Published: February 2012

This work approaches the development of a procedure for separation and determination of five trace metals (Co, Cd, Pb, Ni, and Cu) from petroleum produced formation water. This procedure uses a styrene divinyl-benzene polymeric resin modified with 4-(5′-bromo-2′-tiazolilazo) orcinol, and the determination was performed by inductively coupled plasma mass spectrometry. A response surface methodology using a Doehlert matrix was used to optimize the solid-phase extraction of the studied elements. By using 50.0 mL of sample solution for separation/preconcentration, limits of quantification of 2.4, 14, 10, 11, and 350 ng L− 1 were obtained for Co, Cd, Pb, Ni, and Cu, respectively. The developed procedure was applied for determination of these trace elements in produced formation water from offshore platforms in the Brazilian Northeast.
Ciência, educação e a possibilidade de novas utopias
Authors: Ruiz Adriano Rodrigues
Published: February 2012

Modern scientific determinism as a parameter for the endurance of scholastic education spirit is herediscussed. The belief in a regular and foreseeable world has helped to annihilate the respect for individuality and hasfostered the pedagogy of repetition and dependency. The current scientific revolution abandons simplified modelsand advocates the end of convictions. It is the threshold of a time in which the individual must perfect his/herintellectual tools for everyday encounters thus opening new horizons for educational utopias
High‐Performance Metal‐Free Solar Cells Using Stamp Transfer Printed Vapor Phase Polymerized Poly(3,4‐Ethylenedioxythiophene) Top Anodes
Authors: Wang Xiangjun , Ishwara Thilini , Gong Wei , Campoy‐Quiles Mariano , Nelson Jenny , Bradley Donal D. C.
Published: February 2012

The use of vapor phase polymerized poly(3,4‐ethylenedioxythiophene) (VPP‐PEDOT) as a metal‐replacement top anode for inverted solar cells is reported. Devices with both i) standard bulk heterojunction blends of poly(3‐hexylthiophene) (P3HT) donor and 1‐(3‐methoxycarbonyl)‐propyl‐1‐phenyl‐(6,6)C60 (PCBM) soluble fullerene acceptor and ii) hybrid inorganic/organic TiO2/P3HT acceptor/donor active layers are studied. Stamp transfer printing methods are used to deposit both the VPP‐PEDOT top anode and a work function enhancing PEDOT:polystyrenesulphonate (PEDOT:PSS) interlayer. The metal‐free devices perform comparably to conventional devices with an evaporated metal top anode, yielding power conversion efficiencies of 3% for bulk heterojunction blend and 0.6% for organic/inorganic hybrid structures. These encouraging results suggest that stamp transfer printed VPP‐PEDOT provides a useful addition to the electrode materials tool‐box available for low temperature and non‐vacuum solar cell fabrication.
Design of an “Active Defense” System as Drug Carriers for Cancer Therapy
Authors: Zhang Jing , Xu Xiao‐Ding , Liu Yun , Liu Chen‐Wei , Chen Xiu‐Hong , Li Cao , Zhuo Ren‐Xi , Zhang Xian‐Zheng
Published: February 2012

A novel intelligent “active defense” system that can specially respond to cancerous tissues for drug release was designed and prepared. The “active defense” system consists of a biodegradable dextran microgel core cross‐linked by a Schiff's base and a surrounding layer formed by Layer‐by‐Layer (LbL) assembly. The loading and release of macromolecular model drug, dex‐FITC, as well as antineoplastic drug, DOX, was investigated. The in vitro cell inhibition and drug release behavior of the drug delivery system were studied and the results showed that the entrapped drug could be explosively released from the microcapsules and thereafter taken up by cancer cells upon the trigger of the acidic environment around tumor tissues.
Exploring the Origin of the Temperature‐Dependent Behavior of PbS Nanocrystal Thin Films and Solar Cells
Authors: Szendrei Krisztina , Speirs Mark , Gomulya Widianta , Jarzab Dorota , Manca Marianna , Mikhnenko Oleksandr V. , Yarema Maksym , Kooi Bart J. , Heiss Wolfgang , Loi Maria A.
Published: February 2012

Temperature‐dependent studies of the electrical and optical properties of cross‐linked PbS nanocrystal (NC) solar cells can provide deeper insight into their working mechanisms. It is demonstrated that the overall effect of temperature on the device efficiency originates from the temperature dependence of the open‐circuit voltage and the short‐circuit current, while the fill factor remains approximately constant. Extensive modeling provides signs of band‐like transport in the inhomogeneously coupled NC active layer and shows that the charge transport is dominated by diffusion. Moreover, via low temperature absorption and photoluminescence (PL) measurements, it is shown that the optical properties of PbS thin films before and after benzenedithiol (BDT) treatment exhibit very distinct behavior. After BDT treatment, both the optical density (OD) and PL are shifted to lower energies, indicating the occurrence of electronic wave function overlap between adjacent NCs. Decrease of the temperature leads to additional red‐shift of the OD and PL spectra, which is explained by the well‐known temperature dependence of the PbS NCs' bandgap. Moreover, BDT treated PbS NCs show unusual properties, such as decrease of the PL signal and broadening of the spectra at low temperatures. These features can be attributed to the partial relaxation of the quantum confinement and the opening of new radiative and nonradiative pathways for recombination at lower temperatures due to the presence of trap states.
Operational Stability of Organic Field‐Effect Transistors
Authors: Bobbert Peter A. , Sharma Abhinav , Mathijssen Simon G. J. , Kemerink Martijn , de Leeuw Dago M.
Published: February 2012

Organic field‐effect transistors (OFETs) are considered in technological applications for which low cost or mechanical flexibility are crucial factors. The environmental stability of the organic semiconductors used in OFETs has improved to a level that is now sufficient for commercialization. However, serious problems remain with the stability of OFETs under operation. The causes for this have remained elusive for many years. Surface potentiometry together with theoretical modeling provide new insights into the mechanisms limiting the operational stability. These indicate that redox reactions involving water are involved in an exchange of mobile charges in the semiconductor with protons in the gate dielectric. This mechanism elucidates the established key role of water and leads in a natural way to a universal “stress function”, describing the stretched exponential‐like time dependence ubiquitously observed. Further study is needed to determine the generality of the mechanism and the role of other mechanisms.
Familial 4.8 MB deletion on 18q23 associated with growth hormone insufficiency and phenotypic variability
Authors: Margarit Ester , Morales Carme , Rodríguez‐Revenga Laia , Monné Raquel , Badenas Cèlia , Soler Anna , Clusellas Núria , Mademont Irene , Sánchez Aurora
Published: February 2012

The deletion of the long arm of chromosome 18 causes a contiguous gene deletion syndrome with a highly variable phenotype, usually related to the extent of the deleted region. The most commonly reported clinical features include: decreased growth, microcephaly, facial abnormalities, hypotonia, developmental delay, intellectual disability, congenital aural atresia with hearing impairment and limb anomalies. Here we report on a familial terminal deletion of 18q23 region transmitted from a mother to two daughters, resulting in a remarkable phenotypic variability. The deletion was first detected by conventional cytogenetic analysis in one daughter and subsequently characterized using fluorescence in situ hybridization (FISH) and array‐CGH. FISH analysis using subtelomeric 18p and 18q probes confirmed the 18qter deletion in the three patients, and FISH with a whole chromosome painting probe specific for chromosome 18 excluded rearrangements with other chromosomes. Array‐CGH analysis allowed us to precisely define the extent of the deletion, which spans 4.8 Mb from 71,236,891 to 76,093,303 genomic positions and includes GALR1 and MBP genes, among others. High‐resolution analysis of the deletion, besides a detailed clinical assessment, has provided important data for phenotype–genotype correlation and genetic counseling in this family. Furthermore, this study adds valuable information for phenotype–genotype correlation in 18q‐ syndrome and might facilitate future search for candidate genes involved in each phenotypic trait. © 2012 Wiley Periodicals, Inc.
Ophthalmic features of CHARGE syndrome with CHD7 mutations
Authors: Nishina Sachiko , Kosaki Rika , Yagihashi Tatsuhiko , Azuma Noriyuki , Okamoto Nobuhiko , Hatsukawa Yoshikazu , Kurosawa Kenji , Yamane Takahiro , Mizuno Seiji , Tsuzuki Kinichi , Kosaki Kenjiro
Published: February 2012

Coloboma and various ocular abnormalities have been described in CHARGE syndrome, although the severity of visual impairment varies from case to case. We conducted a multicenter study to clarify the ophthalmic features of patients with molecularly confirmed CHARGE syndrome. Thirty‐eight eyes in 19 patients with CHARGE syndrome and confirmed CHD7 mutations treated at four centers were retrospectively studied. Colobomata affected the posterior segment of 35 eyes in 18 patients. Both retinochoroidal and optic disk colobomata were bilaterally observed in 15 patients and unilaterally observed in 3 patients. The coloboma involved the macula totally or partially in 21 eyes of 13 patients. We confirmed that bilateral large retinochoroidal colobomata represents a typical ophthalmic feature of CHARGE syndrome in patients with confirmed CHD7 mutations; however, even eyes with large colobomata can form maculas. The anatomical severity of the eye defect was graded according to the presence of colobomata, macula defect, and microphthalmos. A comparison of the severity in one eye with that in the other eye revealed a low‐to‐moderate degree of agreement between the two eyes, reflecting the general facial asymmetry of patients with CHARGE syndrome. The location of protein truncation and the anatomical severity of the eyes were significantly correlated. We suggested that the early diagnosis of retinal morphology and function may be beneficial to patients, since such attention may determine whether treatment for amblyopia, such as optical correction and patching, will be effective in facilitating the visual potential or whether care for poor vision will be needed. © 2012 Wiley Periodicals, Inc.
The importance of advanced parental age in the origin of neurofibromatosis type 1
Authors: Snajderova Marta , Riccardi Vincent M. , Petrak Borivoj , Zemkova Daniela , Zapletalova Jirina , Mardesic Tonko , Petrakova Alena , Lanska Vera , Marikova Tatiana , Bendova Sarka , Havlovicova Marketa , Kaluzova Marie
Published: February 2012

Von Recklinghausen neurofibromatosis (NF1) is an autosomal dominant disorder with a prevalence about 1/3,000 (1/2,000–1/5,000 in various population‐based studies). About 30–50% of cases are sporadic, resulting from a new mutation. NF1 is fully penetrant by mid‐childhood, stigmata, and medical problems (neurological, dermatological, endocrine, ophthalmological, oncological) are highly variable. Advanced paternal age (APA) has been known to increase the risk of new germline mutations that contribute to the presence of a variety of genetic diseases in the human population. The trend in developed countries has been toward higher parental age due to various reasons. In a cross‐sectional study, in two university hospital centers, data on parental age of 103 children (41 female) born between 1976 and 2005 with sporadic NF1 were analyzed. Parental age at birth was compared with the Czech general population matched to birth year. The mean NF1 sporadic case paternal age at birth was 32.0 years (95% CI 30.7–33.3 years) compared with 28.8 years (95% CI 28.6–29.1 years) in the general population (P < 0.001). The mean maternal age at birth was 27.4 years (95% CI 26.3–28.5 years) compared with 25.8 years (95% CI 25.5–26.0 years) in the general population (P < 0.05). The case‐control difference in the father's age was higher than it was for the mother's age. Sporadic NF1 cases accounted for 35.6% of our entire NF1 cohort. We confirmed an association of advanced parental and particularly paternal age with the occurrence of sporadic NF1. © 2012 Wiley Periodicals, Inc.