Impact of Solvent Quality on the Density Profiles of Looped Triblock Copolymer Brushes by Neutron Reflectivity Measurements

Preferential adsorption of poly(2-vinylpyridine)-deuterated polystyrene-poly(2-vinylpyridine) (PVP-dPS-PVP) triblock copolymers from toluene onto silicon leads to the formation of dPS loops tethered by the PVP end blocks. Using neutron reflectometry, we have determined the segment density profiles of these looped polymer brushes in toluene, a good solvent for the dPS block, and in cyclohexane at 20 °C (poor solvent), 32 °C, (near-Θ solvent), and 50 °C (marginal solvent). While the swelling behavior qualitatively agrees with that observed for singly grafted brushes, there are interesting differences in the local structural details: In a good solvent, the segment density profiles are composed of an inner parabolic region and a long, extended tail. In cyclohexane, the profiles are described by exponential decays. We ascribe these features to a novel polydispersity effect that arises due to tethering the PS loops by both ends. The results also show that the less dense layers undergo more significant changes in swollen height as solvent quality is changed and that the looped brushes of different molecular weight, asymmetry, and tethering density adhere to scaling relationships derived for lightly cross-linked polymer gels.

Next Generation Catalogs (NGCs) : Meeting User Needs with Metadata and Search Technology

Recommendations • Become a beta partner with vendor • Test load collections before going live • Update cataloging codes to benefit your community • Don’t expect to drastically change cataloging practices

Systematic Evaluation of Extraction Methods for Multiplatform-Based Metabotyping: Application to the Fasciola hepatica Metabolome

Combining data from multiple analytical platforms is essential for comprehensive study of the molecular phenotype (metabotype) of a given biological sample. The metabolite profiles generated are intrinsically dependent on the analytical platforms, each requiring optimization of instrumental parameters, separation conditions, and sample extraction to deliver maximal biological information. An in-depth evaluation of extraction protocols for characterizing the metabolome of the hepatobiliary fluke Fasciola hepatica, using ultra performance liquid chromatography and capillary electrophoresis coupled with mass spectroscopy is presented. The spectrometric methods were characterized by performance, and metrics of merit were established, including precision, mass accuracy, selectivity, sensitivity, and platform stability. Although a core group of molecules was common to all methods, each platform contributed a unique set, whereby 142 metabolites out of 14,724 features were identified. A mixture design revealed that the chloroform:methanol:water proportion of 15:59:26 was globally the best composition for metabolite extraction across UPLC-MS and CE-MS platforms accommodating different columns and ionization modes. Despite the general assumption of the necessity of platform-adapted protocols for achieving effective metabotype characterization, we show that an appropriately designed single extraction procedure is able to fit the requirements of all technologies. This may constitute a paradigm shift in developing efficient protocols for high-throughput metabolite profiling with more-general analytical applicability.

DNA damage profiles induced by sunlight at different latitudes

Despite growing knowledge on the biological effects of ultraviolet (UV) radiation on human health and ecosystems, it is still difficult to predict the negative impacts of the increasing incidence of solar UV radiation in a scenario of global warming and climate changes. Hence, the development and application of DNA-based biological sensors to monitor the solar UV radiation under different environmental conditions is of increasing importance. With a mind to rendering a molecular view-point of the genotoxic impact of sunlight, field experiments were undertaken with a DNA-dosimeter system in parallel with physical photometry of solar UVB/UVA radiation, at various latitudes in South America. Onapplying biochemical and immunological approaches based on specific DNA-repair enzymes and antibodies, for evaluating sunlight-induced DNA damage profiles, it became clear that the genotoxic potential of sunlight does indeed vary according to latitude. Notwithstanding, while induction of oxidized DNA bases is directly dependent on an increase in latitude, the generation of 6-4PPs is inversely so, whereby the latter can be regarded as a biomolecular marker of UVB incidence. This molecular DNA lesion-pattern largely reflects the relative incidence of UVA and UVB energy at any specific latitude. Hereby is demonstrated the applicability of this DNA-based biosensor for additional, continuous field experiments, as a means of registering variations in the genotoxic impact of solar UV radiation. Environ. Mol. Mutagen. 2012. (c) 2012 Wiley Periodicals, Inc.

Soil properties in a sugarcane plantation after the application of treated sewage effluent and phosphogypsum in Brazil

In a field experiment performed in Lins County (Sao Paulo State, Brazil), treated sewage effluent (TSE) irrigation increased sugarcane yield but caused an excessive increase in the exchangeable sodium percentage (ESP) and clay dispersion after 16 months due to an intense irrigation regime (2500 mm/16 months) with sodium rich effluents. After two additional complete cycles with lower TSE irrigation rates (1200 mm year(-1)), 1700 kg ha(-1) of phosphogypsum was added to a section of the irrigated plots to evaluate its residence time and its implications on Na+ dynamics and other soil properties. Undisturbed soil cores were taken 2 years after phosphogypsum application to verify soil physical properties up to 0.2 m depth, and disturbed soil samples were taken every year up to 1 m depth for chemical analyses. After 5 years of consecutive TSE irrigation (2005-2010), soil acidity (pH approximate to 5) and basic cations (Ca approximate to 12, Mg approximate to 6 and K approximate to 2 mmol(c) kg(-1)) were maintained in adequate conditions for plant development without the necessity of liming, while acidity was increased (pH approximate to 4.5) and Ca (approximate to 9 mmol(c) kg(-1)), and the Mg (approximate to 4.5 mmol(c) kg(-1)) concentration decreased in the rainfed without phosphogypsum treatment. An increase in water retention capacity at -30 (from 0.14 to 0.17 m(3) m(-3)) and -1500 kPa (from 0.08 to 0.12 m(3) m(-3)) potentials was also observed in all TSE irrigated treatments. The plots with a phosphogypsum treatment showed average increases of 2 mmol(c) kg(-1) of Ca2+ and 7 mg kg(-1) of S-SO42- in all soil profiles and an average reduction of 2 mmol(c) kg(-1) of Na+ up to 0.4 m from 2008 to 2009. However, the extent of the chemical effects was greater after the first year compared to the second year. The high concentration of Na+ found in previous studies performed in the same area returned to low concentrations after continued TSE irrigation at lower rates, even without the phosphogypsum application. An unusual phosphorus migration was observed to the 0.4-0.8 m soil layer as a result of TSE irrigation, most likely due to a high pH and a Na carbonate-dominated TSE. (C) 2012 Elsevier B.V. All rights reserved.

Performance and radial distribution profiles of a variable flow rate sprinkler developed for precision irrigation

Variable rate sprinklers (VRS) have been developed to promote localized water application of irrigated areas. In Precision Irrigation, VRS permits better control of flow adjustment and, at the same time, provides satisfactory radial distribution profiles for various pressures and flow rates are really necessary. The objective of this work was to evaluate the performance and radial distribution profiles of a developed VRS which varies the nozzle cross sectional area by moving a pin in or out using a stepper motor. Field tests were performed under different conditions of service pressure, rotation angles imposed on the pin and flow rate which resulted in maximal water throw radiuses ranging from 7.30 to 10.38 m. In the experiments in which the service pressure remained constant, the maximal throw radius varied from 7.96 to 8.91 m. Averages were used of repetitions performed under conditions without wind or with winds less than 1.3 m s-1. The VRS with the four stream deflector resulted in greater water application throw radius compared to the six stream deflector. However, the six stream deflector had greater precipitation intensities, as well as better distribution. Thus, selection of the deflector to be utilized should be based on project requirements, respecting the difference in the obtained results. With a small opening of the nozzle, the VRS produced small water droplets that visually presented applicability for foliar chemigation. Regarding the comparison between the estimated and observed flow rates, the stepper motor produced excellent results.

Structural and reduction studies of ZrO2-CeO2:Ni for application in SOFC anodes.

Zirconia-ceria solid-solutions are extensively used as promoters for three-way catalysts, which are applied in the control of NOx, CO and hydrocarbons emission from automotive exhausts. In addition, thesematerials can be used as anodes in solid oxide fuel cells (SOFCs) operated with hydrocarbons. There areonly few works on ZrO2-CeO2 ordered mesoporous materials for catalytic applications and for anodes inSOFCs. The interest in these anodes relies on the fact that ZrO2-CeO2materials are mixed ionic/electronic conductors in reducing atmosphere and, therefore, fuel oxidation is produced on its entire surface, while it only occurs in the [anode/electrolyte/gas] interface (triple-phase boundaries) for electronic conductors. In this work, a synthesis method was developed usingZr and Ce chloride precursors, HCl aqueous solution, Pluronic P123 as the structure directing agent, NH4OH to adjust the pH (3-4) and a Teflon autoclave to perform hydrothermal treatment (80ºC/48 hours). The samples were dried and calcined, until 540ºC in N2and 4 hours in air. The X-ray diffraction data showed that powders with higher CeO2 content are formed by a larger fraction of the cubic CeO2 phase, while for a lower CeO2content the major crystalline structure is the tetragonal ZrO2 phase. The NiO impregnation was made with an ethanol dispersion of Ni(NO3)×6H2O. The resulting powder was calcinated in air until 350ºC for 2 hours. Temperature-programmed reduction (TPR) data were collected in order to evaluate the reduction profiles of ZrO2-x%CeO2:Ni samples in H2/Ar atmosphere. Results showed lower reduction temperatures for all ceria content in samples comparing to a NiO standard.

Application of 137Cs and 210Pb radionuclides to determine sedimentation rates of recent sediments from admiraty Bay, Antarctica Peninsula

Studies about natural and artificial radionuclides in areas such as the Antarctic are key to understand natural and dynamic processes in marine environments. These studies are important to determine levels of radioactive elements and local sedimentation rates. Five marine sediment cores were collected in different points of Admiralty Bay, in the Antarctic Peninsula. The purpose of this study was to determine 137Cs, 226Ra and 210Pb and sedimentation rates at each site. 137Cs, 210Pb and 226Ra were assayed by gamma-counting through direct measurement of the peak at 661 keV, 47 keV and 609 keV, respectively. Sedimentation rates were obtained by 137Cs and 210Pb (CIC and CRS). The activities for 137Cs ranged from 0.84 to 7.09 Bq kg-1; to 226Ra from 6.77 to 31.07 Bq kg-1 and for 210Pb ranged from 1.10 to 36.90 Bq kg-1. The sedimentation rates obtained by the three models ranged from 0.11±0.01 cm y-1 to 0.46±0.05 cm y-1. The levels of 137Cs registered in this study, as well as in other studies in the Antarctic region indicate that global fallout is the main cause of artificial radionuclides present in this environment, since the Antarctic has not suffered a direct action of human activities that released radioactive elements. The possible grain size variations that occur in the studied points of Admiralty Bay may explain the differences found in the vertical distribution of radionuclides, because of the different values of sedimentation rates and respective dating determined in their profiles

NMR, Metabonomics and Molecular Profiles: Applications to the Quality Assessment of Foodstuffs

Nuclear Magnetic Resonance (NMR) is a branch of spectroscopy that is based on the fact that many atomic nuclei may be oriented by a strong magnetic field and will absorb radiofrequency radiation at characteristic frequencies. The parameters that can be measured on the resulting spectral lines (line positions, intensities, line widths, multiplicities and transients in time-dependent experi-ments) can be interpreted in terms of molecular structure, conformation, molecular motion and other rate processes. In this way, high resolution (HR) NMR allows performing qualitative and quantitative analysis of samples in solution, in order to determine the structure of molecules in solution and not only. In the past, high-field NMR spectroscopy has mainly concerned with the elucidation of chemical structure in solution, but today is emerging as a powerful exploratory tool for probing biochemical and physical processes. It represents a versatile tool for the analysis of foods. In literature many NMR studies have been reported on different type of food such as wine, olive oil, coffee, fruit juices, milk, meat, egg, starch granules, flour, etc using different NMR techniques. Traditionally, univariate analytical methods have been used to ex-plore spectroscopic data. This method is useful to measure or to se-lect a single descriptive variable from the whole spectrum and , at the end, only this variable is analyzed. This univariate methods ap-proach, applied to HR-NMR data, lead to different problems due especially to the complexity of an NMR spectrum. In fact, the lat-ter is composed of different signals belonging to different mole-cules, but it is also true that the same molecules can be represented by different signals, generally strongly correlated. The univariate methods, in this case, takes in account only one or a few variables, causing a loss of information. Thus, when dealing with complex samples like foodstuff, univariate analysis of spectra data results not enough powerful. Spectra need to be considered in their wholeness and, for analysing them, it must be taken in consideration the whole data matrix: chemometric methods are designed to treat such multivariate data. Multivariate data analysis is used for a number of distinct, differ-ent purposes and the aims can be divided into three main groups: • data description (explorative data structure modelling of any ge-neric n-dimensional data matrix, PCA for example); • regression and prediction (PLS); • classification and prediction of class belongings for new samples (LDA and PLS-DA and ECVA). The aim of this PhD thesis was to verify the possibility of identify-ing and classifying plants or foodstuffs, in different classes, based on the concerted variation in metabolite levels, detected by NMR spectra and using the multivariate data analysis as a tool to inter-pret NMR information. It is important to underline that the results obtained are useful to point out the metabolic consequences of a specific modification on foodstuffs, avoiding the use of a targeted analysis for the different metabolites. The data analysis is performed by applying chemomet-ric multivariate techniques to the NMR dataset of spectra acquired. The research work presented in this thesis is the result of a three years PhD study. This thesis reports the main results obtained from these two main activities: A1) Evaluation of a data pre-processing system in order to mini-mize unwanted sources of variations, due to different instrumental set up, manual spectra processing and to sample preparations arte-facts; A2) Application of multivariate chemiometric models in data analy-sis.

Metadata editing: un'implementazione per Open Office

The purpose of this thesis is to enhance the functionalities of GAFFE, a flexible, interactive and user-friendly application for editing metadata in office documents by supporting different ontologies stored inside and outside of the digital document, by adding new views and forms and by improving its ease of use.

Development of the optimal estimation method for inversion of stratospheric emission spectra and validation of HNO3 profiles

This doctoral thesis focuses on ground-based measurements of stratospheric nitric acid (HNO3)concentrations obtained by means of the Ground-Based Millimeter-wave Spectrometer (GBMS). Pressure broadened HNO3 emission spectra are analyzed using a new inversion algorithm developed as part of this thesis work and the retrieved vertical profiles are extensively compared to satellite-based data. This comparison effort I carried out has a key role in establishing a long-term (1991-2010), global data record of stratospheric HNO3, with an expected impact on studies concerning ozone decline and recovery. The first part of this work is focused on the development of an ad hoc version of the Optimal Estimation Method (Rodgers, 2000) in order to retrieve HNO3 spectra observed by means of GBMS. I also performed a comparison between HNO3 vertical profiles retrieved with the OEM and those obtained with the old iterative Matrix Inversion method. Results show no significant differences in retrieved profiles and error estimates, with the OEM providing however additional information needed to better characterize the retrievals. A final section of this first part of the work is dedicated to a brief review on the application of the OEM to other trace gases observed by GBMS, namely O3 and N2O. The second part of this study deals with the validation of HNO3 profiles obtained with the new inversion method. The first step has been the validation of GBMS measurements of tropospheric opacity, which is a necessary tool in the calibration of any GBMS spectra. This was achieved by means of comparisons among correlative measurements of water vapor column content (or Precipitable Water Vapor, PWV) since, in the spectral region observed by GBMS, the tropospheric opacity is almost entirely due to water vapor absorption. In particular, I compared GBMS PWV measurements collected during the primary field campaign of the ECOWAR project (Bhawar et al., 2008) with simultaneous PWV observations obtained with Vaisala RS92k radiosondes, a Raman lidar, and an IR Fourier transform spectrometer. I found that GBMS PWV measurements are in good agreement with the other three data sets exhibiting a mean difference between observations of ~9%. After this initial validation, GBMS HNO3 retrievals have been compared to two sets of satellite data produced by the two NASA/JPL Microwave Limb Sounder (MLS) experiments (aboard the Upper Atmosphere Research Satellite (UARS) from 1991 to 1999, and on the Earth Observing System (EOS) Aura mission from 2004 to date). This part of my thesis is inserted in GOZCARDS (Global Ozone Chemistry and Related Trace gas Data Records for the Stratosphere), a multi-year project, aimed at developing a long-term data record of stratospheric constituents relevant to the issues of ozone decline and expected recovery. This data record will be based mainly on satellite-derived measurements but ground-based observations will be pivotal for assessing offsets between satellite data sets. Since the GBMS has been operated for more than 15 years, its nitric acid data record offers a unique opportunity for cross-calibrating HNO3 measurements from the two MLS experiments. I compare GBMS HNO3 measurements obtained from the Italian Alpine station of Testa Grigia (45.9° N, 7.7° E, elev. 3500 m), during the period February 2004 - March 2007, and from Thule Air Base, Greenland (76.5°N 68.8°W), during polar winter 2008/09, and Aura MLS observations. A similar intercomparison is made between UARS MLS HNO3 measurements with those carried out from the GBMS at South Pole, Antarctica (90°S), during the most part of 1993 and 1995. I assess systematic differences between GBMS and both UARS and Aura HNO3 data sets at seven potential temperature levels. Results show that, except for measurements carried out at Thule, ground based and satellite data sets are consistent within the errors, at all potential temperature levels.

Application of innovative methods of source apportionment in air contamination assessment

In this work, new tools in atmospheric pollutant sampling and analysis were applied in order to go deeper in source apportionment study. The project was developed mainly by the study of atmospheric emission sources in a suburban area influenced by a municipal solid waste incinerator (MSWI), a medium-sized coastal tourist town and a motorway. Two main research lines were followed. For what concerns the first line, the potentiality of the use of PM samplers coupled with a wind select sensor was assessed. Results showed that they may be a valid support in source apportionment studies. However, meteorological and territorial conditions could strongly affect the results. Moreover, new markers were investigated, particularly focusing on the processes of biomass burning. OC revealed a good biomass combustion process indicator, as well as all determined organic compounds. Among metals, lead and aluminium are well related to the biomass combustion. Surprisingly PM was not enriched of potassium during bonfire event. The second research line consists on the application of Positive Matrix factorization (PMF), a new statistical tool in data analysis. This new technique was applied to datasets which refer to different time resolution data. PMF application to atmospheric deposition fluxes identified six main sources affecting the area. The incinerator’s relative contribution seemed to be negligible. PMF analysis was then applied to PM2.5 collected with samplers coupled with a wind select sensor. The higher number of determined environmental indicators allowed to obtain more detailed results on the sources affecting the area. Vehicular traffic revealed the source of greatest concern for the study area. Also in this case, incinerator’s relative contribution seemed to be negligible. Finally, the application of PMF analysis to hourly aerosol data demonstrated that the higher the temporal resolution of the data was, the more the source profiles were close to the real one.

Fatty acid and peptide profiles in plasma membrane and membrane rafts of PUFA supplemented RAW264.7 macrophages

The eukaryotic cell membrane possesses numerous complex functions, which are essential for life. At this, the composition and the structure of the lipid bilayer are of particular importance. Polyunsaturated fatty acids may modulate the physical properties of biological membranes via alteration of membrane lipid composition affecting numerous physiological processes, e.g. in the immune system. In this systematic study we present fatty acid and peptide profiles of cell membrane and membrane rafts of murine macrophages that have been supplemented with saturated fatty acids as well as PUFAs from the n-3, the n-6 and the n-9 family. Using fatty acid composition analysis and mass spectrometry-based peptidome profiling we found that PUFAs from both the n-3 and the n-6 family have an impact on lipid and protein composition of plasma membrane and membrane rafts in a similar manner. In addition, we found a relation between the number of bis-allyl-methylene positions of the PUFA added and the unsaturation index of plasma membrane as well as membrane rafts of supplemented cells. With regard to the proposed significance of lipid microdomains for disease development and treatment our study will help to achieve a targeted dietary modulation of immune cell lipid bilayers.

Radiation doses along selected flight profiles during two extreme solar cosmic ray events

The radiation dose rates at flight altitudes may be hazardously increased during solar cosmic ray events. Within the scope of this paper we investigate the total accumulated radiation doses, i.e. the contribution of galactic and solar cosmic rays, during the two extreme solar cosmic ray events on 29 September 1989 and on 20 January 2005 along selected flight profiles. In addition, the paper discusses the consequences of possible solar cosmic ray flux approximations on the results of the radiation dose computations.