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Sample records for oxygen-containing functional groups

  1. Effects of Oxygen-Containing Functional Groups on Supercapacitor Performance

    SciTech Connect

    Kerisit, Sebastien N.; Schwenzer, Birgit; Vijayakumar, M.

    2014-07-03

    Molecular dynamics (MD) simulations of the interface between graphene and the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMIM OTf) were carried out to gain molecular-level insights into the performance of graphene-based supercapacitors and, in particular, determine the effects of the presence of oxygen-containing defects at the graphene surface on their integral capacitance. The MD simulations predict that increasing the surface coverage of hydroxyl groups negatively affects the integral capacitance, whereas the effect of the presence of epoxy groups is much less significant. The calculated variations in capacitance are found to be directly correlated to the interfacial structure. Indeed, hydrogen bonding between hydroxyl groups and SO3 anion moieties prevents BMIM+ and OTf- molecules from interacting favorably in the dense interfacial layer and restrains the orientation and mobility of OTf- ions, thereby reducing the permittivity of the ionic liquid at the interface. The results of the molecular simulations can facilitate the rational design of electrode materials for supercapacitors.

  2. Effect of Oxygen-containing Functional Groups on Protein Stability in Ionic Liquid Solutions

    NASA Technical Reports Server (NTRS)

    Turner, Megan B.; Holbrey, John D.; Spear, Scott K.; Pusey, Marc L.; Rogers, Robin D.

    2004-01-01

    The ability of functionalized ionic liquids (ILs) to provide an environment of increased stability for biomolecules has been studied. Serum albumin is an inexpensive, widely available protein that contributes to the overall colloid osmotic blood pressure within the vascular system. Albumin is used in the present study as a marker of biomolecular stability in the presence of various ILs in a range of concentrations. The incorporation of hydroxyl functionality into the methylimidazolium-based cation leads to increased protein stability detected by fluorescence spectroscopy and circular dichroic (CD) spectrometry.

  3. Oxygen-containing functional group-facilitated CO2 capture by carbide-derived carbons

    PubMed Central

    2014-01-01

    A series of carbide-derived carbons (CDCs) with different surface oxygen contents were prepared from TiC powder by chlorination and followed by HNO3 oxidation. The CDCs were characterized systematically by a variety of means such as Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ultimate analysis, energy dispersive spectroscopy, N2 adsorption, and transmission electron microscopy. CO2 adsorption measurements showed that the oxidation process led to an increase in CO2 adsorption capacity of the porous carbons. Structural characterizations indicated that the adsorbability of the CDCs is not directly associated with its microporosity and specific surface area. As evidenced by elemental analysis, X-ray photoelectron spectroscopy, and energy dispersive spectroscopy, the adsorbability of the CDCs has a linear correlation with their surface oxygen content. The adsorption mechanism was studied using quantum chemical calculation. It is found that the introduction of O atoms into the carbon surface facilitates the hydrogen bonding interactions between the carbon surface and CO2 molecules. This new finding demonstrated that not only the basic N-containing groups but also the acidic O-containing groups can enhance the CO2 adsorbability of porous carbon, thus providing a new approach to design porous materials with superior CO2 adsorption capacity. PMID:24872796

  4. Effects of Oxygen Element and Oxygen-Containing Functional Groups on Surface Wettability of Coal Dust with Various Metamorphic Degrees Based on XPS Experiment.

    PubMed

    Zhou, Gang; Xu, Cuicui; Cheng, Weimin; Zhang, Qi; Nie, Wen

    2015-01-01

    To investigate the difference of surface oxygen element and oxygen-containing functional groups among coal dusts with different metamorphic degrees and their influence on surface wettability, a series of X-ray photoelectron spectroscopy experiments on 6 coal samples are carried out. The result demonstrates that the O/C ratio of coal surface shows an overall increasing trend compared with the result of its elements analysis. As the metamorphic degree increases, the O/C ratio on the surface gradually declines and the hydrophilic groups tend to fall off from coal surface. It could be found that different coals show different surface distributions of carboxyl and hydroxyl which are considered as the greatest promoter to the wettability of coal surface. With the change of metamorphic degree, the distribution of ether group is irregular while the carbonyl distribution keeps stable. In general, as the metamorphic degree goes higher, the content of oxygen-containing polar group tends to reduce. According to the measurement results, the contact angle is negatively related to the content of oxygen element, surface oxygen, and polar groups. In addition, compared with surface oxygen content, the content of oxygen-containing polar group serves as a more reasonable indicator of coal dust wettability.

  5. Effects of Oxygen Element and Oxygen-Containing Functional Groups on Surface Wettability of Coal Dust with Various Metamorphic Degrees Based on XPS Experiment

    PubMed Central

    Zhou, Gang; Xu, Cuicui; Cheng, Weimin; Zhang, Qi; Nie, Wen

    2015-01-01

    To investigate the difference of surface oxygen element and oxygen-containing functional groups among coal dusts with different metamorphic degrees and their influence on surface wettability, a series of X-ray photoelectron spectroscopy experiments on 6 coal samples are carried out. The result demonstrates that the O/C ratio of coal surface shows an overall increasing trend compared with the result of its elements analysis. As the metamorphic degree increases, the O/C ratio on the surface gradually declines and the hydrophilic groups tend to fall off from coal surface. It could be found that different coals show different surface distributions of carboxyl and hydroxyl which are considered as the greatest promoter to the wettability of coal surface. With the change of metamorphic degree, the distribution of ether group is irregular while the carbonyl distribution keeps stable. In general, as the metamorphic degree goes higher, the content of oxygen-containing polar group tends to reduce. According to the measurement results, the contact angle is negatively related to the content of oxygen element, surface oxygen, and polar groups. In addition, compared with surface oxygen content, the content of oxygen-containing polar group serves as a more reasonable indicator of coal dust wettability. PMID:26257980

  6. Characterization of Oxygen Containing Functional Groups on Carbon Materials with Oxygen K-edge X-ray Absorption Near Edge Structure Spectroscopy

    SciTech Connect

    K Kim; P Zhu; L Na; X Ma; Y Chen

    2011-12-31

    Surface functional groups on carbon materials are critical to their surface properties and related applications. Many characterization techniques have been used to identify and quantify the surface functional groups, but none is completely satisfactory especially for quantification. In this work, we used oxygen K-edge X-ray absorption near edge structure (XANES) spectroscopy to identify and quantify the oxygen containing surface functional groups on carbon materials. XANES spectra were collected in fluorescence yield mode to minimize charging effect due to poor sample conductivity which can potentially distort XANES spectra. The surface functional groups are grouped into three types, namely carboxyl-type, carbonyl-type, and hydroxyl-type. XANES spectra of the same type are very similar while spectra of different types are significantly different. Two activated carbon samples were analyzed by XANES. The total oxygen contents of the samples were estimated from the edge step of their XANES spectra, and the identity and abundance of different functional groups were determined by fitting of the sample XANES spectrum to a linear combination of spectra of the reference compounds. It is concluded that oxygen K-edge XANES spectroscopy is a reliable characterization technique for the identification and quantification of surface functional groups on carbon materials.

  7. Improvement of oxygen-containing functional groups on olive stones activated carbon by ozone and nitric acid for heavy metals removal from aqueous phase.

    PubMed

    Bohli, Thouraya; Ouederni, Abdelmottaleb

    2016-08-01

    Recently, modification of surface structure of activated carbons in order to improve their adsorption performance toward especial pollutants has gained great interest. Oxygen-containing functional groups have been devoted as the main responsible for heavy metal binding on the activated carbon surface; their introduction or enhancement needs specific modification and impregnation methods. In the present work, olive stones activated carbon (COSAC) undergoes surface modifications in gaseous phase using ozone (O3) and in liquid phase using nitric acid (HNO3). The activated carbon samples were characterized using N2 adsorption-desorption isotherm, SEM, pHpzc, FTIR, and Boehm titration. The activated carbon parent (COSAC) has a high surface area of 1194 m(2)/g and shows a predominantly microporous structure. Oxidation treatments with nitric acid and ozone show a decrease in both specific surface area and micropore volumes, whereas these acidic treatments have led to a fixation of high amount of surface oxygen functional groups, thus making the carbon surface more hydrophilic. Activated carbon samples were used as an adsorbent matrix for the removal of Co(II), Ni(II), and Cu(II) heavy metal ions from aqueous solutions. Adsorption isotherms were obtained at 30 °C, and the data are well fitted to the Redlich-Peterson and Langmuir equation. Results show that oxidized COSACs, especially COSAC(HNO3), are capable to remove more Co(II), Cu(II), and Ni(II) from aqueous solution. Nitric acid-oxidized olive stones activated carbon was tested in its ability to remove metal ions from binary systems and results show an important maximum adsorbed amount as compared to single systems.

  8. Effects of pore sizes and oxygen-containing functional groups on desulfurization activity of Fe/NAC prepared by ultrasonic-assisted impregnation

    NASA Astrophysics Data System (ADS)

    Shu, Song; Guo, Jia-Xiu; Liu, Xiao-Li; Wang, Xue-Jiao; Yin, Hua-Qiang; Luo, De-Ming

    2016-01-01

    A series of Fe-loaded activated carbons treated by HNO3 (Fe/NAC) were prepared by incipient impregnation method with or without ultrasonic assistance and characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy with energy disperse spectroscope (SEM-EDS), transmission electron microscopy (TEM) and N2 adsorption/desorption. The desulfurization activities were evaluated at a fixed bed reactor under a mixed gas simulated from flue gas. The results showed that desulfurization activity from excellent to poor is as follows: Fe/NAC-60 > Fe/NAC-80 > Fe/NAC-30 > Fe/NAC-15 > Fe/NAC-0 > Fe/NAC-100 > NAC. Fe/NAC-60 exhibits the best desulfurization activity and has breakthrough sulfur capacity of 319 mg/g and breakthrough time of 540 min. The introduction of ultrasonic oscillation does not change the form of Fe oxides on activated carbon but can change the dispersion and relative contents of Fe3O4. The types of oxygen-containing functional groups have no obvious change for all samples but the texture properties show some differences when they are oscillated for different times. The fresh Fe/NAC-60 has a surface area of 1045 m2/g and total pore volume of 0.961 cm3/g with micropore volume of 0.437 cm3/g and is larger than Fe/NAC-0 (823 m2/g, 0.733 and 0.342 cm3/g). After desulfurization, surface area and pore volume of all samples decrease significantly, and those of the exhausted Fe/NAC-60 decrease to 233 m2/g and 0.481 cm3/g, indicating that some byproducts deposit on surface to cover pores. Pore size distribution influences SO2 adsorption, and fresh Fe/NAC-60 has more pore widths centralized at about 0.7 nm and 1.0-2.0 nm and corresponds to an excellent desulfurization activity, showing that micropore is conducive to the removal of SO2.

  9. Municipal sludge-derived carbon anode with nitrogen- and oxygen-containing functional groups for high-performance microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Ma, Xiaoxiao; Feng, Chunhua; Zhou, Weijia; Yu, Hui

    2016-03-01

    The demand for efficient and cost-effective anode materials in microbial fuel cells (MFCs) provides the impetus to use carbon derived from solid waste to support bacterial growth and proliferation. Here we show that the municipal sludge-derived carbon (SC) with a porous structure and abundant surface functional groups is effective in improving performance of MFCs. The SC is coated on the 3-D graphite felt (GF) surface by pyrrole electropolymerization in order to increase the surface cites that are interacted with bacteria, resulting in the formation of PPy/SC-modified GF anode. The scanning electron microscopy analysis indicates that the PPy/SC-modified GF can substantially increase anode surface area. The X-ray photoelectron spectroscopy (XPS) results suggest that the PPy/SC-modified GF anode possesses higher surface N/C ratio and higher relative contents of Odbnd C-NH2 and Odbnd C-O functional groups than other counterpart anodes. These characteristics are essential for increasing bacterial attachment to the anode surface, electron-transfer rate and thus anode performance and power performance. The maximum power density resulting from the PPy/SC-modified GF anode was 568.5 mW m-2 (13.6 W m-3) increased by 1.9, 2.7 and 3.5 times as compared to the PPy/AC-modified GF anode, the PPy alone-modified GF anode and the unmodified GF anode, respectively.

  10. Vapor pressure predictions of multi-functional oxygen-containing organic compounds with COSMO-RS

    NASA Astrophysics Data System (ADS)

    Schröder, Bernd; Fulem, Michal; Martins, Mónia A. R.

    2016-05-01

    Given the recent interest in multi-functional oxygen-containing organic compounds and the need of accurate and consistent data, a complete review and systematic analysis of available experimental vapor pressure data, as published in the original work of (Asher et al., 2002), was performed with the ThermoData Engine (TDE). A revised set of critical evaluated vapor pressure data, including their uncertainties based on the principles of dynamic data evaluation, is here recommended for a total of 58 compounds. COSMO-RS was further used for vapor pressure estimations for these compounds. The quality of the results is discussed in terms of the chemical functionalities of the molecules. To illustrate the partition behaviour of the title compounds under ambient conditions, a simple comparison of volatility binning between estimates and measurements was performed. Since the encountered vapor pressures are rather high, with respect to pressure range of semi-volatile organic compounds (SVOC), a large fraction is expected to stay in the atmosphere rather than to form secondary organic aerosol.

  11. Fluorescence labeling and quantification of oxygen-containing functionalities on the surface of single-walled carbon nanotubes.

    PubMed

    Dementev, Nikolay; Feng, Xue; Borguet, Eric

    2009-07-01

    Fluorescence labeling of surface species (FLOSS) was applied to identify and determine the concentration of oxygen-containing functionalities on single-walled carbon nanotubes (SWCNTs), subjected to two different purification processes (air/HCl and nitric acid treatments) and compared to as-received (nonpurified) SWCNTs. The fluorophores were selected for their ability to covalently bind, with high specificity, to specific types of functionalities (OH, COOH, and CHO). FLOSS revealed that even as-received SWCNTs are not pristine and contain approximately 0.6 atomic % oxygen functionalities. FLOSS showed that, after nitric acid treatment, SWCNTs are approximately 5 times more functionalized than SWCNTs after air/HCl purification (5 versus 1 atomic % oxygen functionalities), supporting the idea that the former purification process is more aggressive than the latter. FLOSS demonstrated that carbonyls are the major functionalities on nitric-acid-purified SWCNTs, suggesting that chemical derivatization strategies might consider exploiting aldehyde or ketone chemistry.

  12. Far-infrared spectra and ring-puckering potential energy functions of two oxygen-containing ring molecules with unusual bonding interactions

    NASA Astrophysics Data System (ADS)

    Choo, J.; Cortez, E.; Laane, Jaan; Majors, R.; Verastegui, R.; Villareal, Genaro R.

    1994-01-01

    Over the past quarter century we have carried out a large number of studies of the ring- puckering vibrations of small ring-molecules. The far-infrared and Raman spectra of these large amplitude motions have been used to determine the molecular conformation and 1-D potential energy functions. The forces which are usually the principal contributors to the potential functions are the ring-angle strain and torsional forces, which often result when CH2 groups are next to each other. In the present study we have examined the far-infrared and Raman spectra of two oxygen-containing molecules which have turned out to have unusual potential energy functions. 1,3-dioxole and 4H-pyran.

  13. New Group-Contribution Approach to Thermochemical Properties of Organic Compounds: Hydrocarbons and Oxygen-Containing Compounds

    NASA Astrophysics Data System (ADS)

    Verevkin, S. P.; Emel'yanenko, V. N.; Diky, V.; Muzny, C. D.; Chirico, R. D.; Frenkel, M.

    2013-09-01

    A new group-contribution approach involving systematic corrections for 1,4-non-bonded carbon-carbon and carbon-oxygen interactions has been proposed. Limits of the applicability of the method, associated with the highly branched structures, were established. Experimental data for enthalpies of formation in the liquid phase, enthalpies of vaporization, and enthalpies of formation in the gas phase for alkanes, alkenes, alkynes, alkylbenzenes, alkanols, ethers, ketones and aldehydes, carboxylic acids, esters, and carbonates were collected and critically evaluated through dynamic data evaluation as implemented in the NIST ThermoData Engine. An automatic procedure for molecular structure "decomposition" was developed, and algorithms for the assessment of expanded uncertainties for the predicted property values were implemented. The combination of these software tools allows for ongoing improvements of the group-contribution parameter set as new experimental data become available. Fifty-two group-contribution parameters and their variances were evaluated for the proposed schema. Based on comparison of critically evaluated and predicted data for all classes of compounds studied, the performance of the new group formulation and associated parameters is superior to that originally suggested by Benson and the update by Cohen without an increase in the number of required parameters.

  14. Oxygen-containing functionalities on the surface of multi-walled carbon nanotubes quantitatively determined by fluorescent labeling

    NASA Astrophysics Data System (ADS)

    Dementev, Nikolay; Ronca, Richard; Borguet, Eric

    2012-10-01

    Control over the type and concentration of functional groups on carbon nanotubes (CNTs) require the use of reliable and sensitive analytical methods to detect, identify and quantify the functionalities on the material. Here we report the results of the selective quantification of aldehyde (together with ketone), carboxylic, and alcohol groups on arc-produced multiwalled carbon nanotubes (MWCNTs) using fluorescent labeling of surface species (FLOSS), combined with surface area and thermogravimetric analysis. The high sensitivity of the fluorescence spectroscopy combined with the selectivity of the chemistry of covalent attachment, allowed us to determine that as-produced MWCNTs contain ∼1.1 at.% carboxylic groups, ∼2.0 at.% aldehydes (and ketones) and <2.0 at.% hydroxyls. Surprisingly, and contrary to the behavior of single walled carbon nanotubes, these concentrations do not appear to increase for acid purified MWCNTs but rather decrease to 0.4 at.% for carboxylic groups; 1.6 at.% for aldehydes (and ketones) and <3.0 at.%, for hydroxyls. Possible explanations for the observation that the acid purified MWCNTs have a lower level of the functionalities compared to the as-produced material are discussed.

  15. Phase Behavior of Oxygen-Containing Polymers in CO2

    SciTech Connect

    Killic, Sevgi; Michalik, Stephen; Wang, Yang; Johnson, J.K.; Enick, R.M.; Beckman, E.J.

    2007-02-20

    The cloud point curves of a series of oxygen-containing polymers in CO2 were measured to attempt to deduce the effect of oxygen functional groups within a polymer on the polymer/CO2 phase behavior. The addition of an ether oxygen to a hydrocarbon polymer, either in the backbone or the side chain, enhances "CO2-philicity" by providing sites for specific interactions with CO2 as well as by enhancing the entropy of mixing by creating more flexible chains with higher free volume. Ab initio calculations show that both ether and ester oxygens provide very attractive interaction sites for CO2 molecules. The binding energy for an isolated ether oxygen with CO2 is larger in magnitude than that for a carbonyl oxygen/CO2 complex. However, acetate functionalized polymers are more CO2-soluble than polymers with only ether functionalities-possibly because acetate functional groups contain a total of three binding modes for CO2 interactions, compared with only one for the ether functional group. Experiments clearly indicate that adding a single methylene group as a spacer between a polymer backbone and either an ether or acetate group exhibits a strong deleterious effect on phase behavior. This effect cannot be explained from our ab initio calculations.

  16. Renormalization group functional equations

    SciTech Connect

    Curtright, Thomas L.; Zachos, Cosmas K.

    2011-03-15

    Functional conjugation methods are used to analyze the global structure of various renormalization group trajectories and to gain insight into the interplay between continuous and discrete rescaling. With minimal assumptions, the methods produce continuous flows from step-scaling {sigma} functions and lead to exact functional relations for the local flow {beta} functions, whose solutions may have novel, exotic features, including multiple branches. As a result, fixed points of {sigma} are sometimes not true fixed points under continuous changes in scale and zeroes of {beta} do not necessarily signal fixed points of the flow but instead may only indicate turning points of the trajectories.

  17. Functional Group Analysis.

    ERIC Educational Resources Information Center

    Smith, Walter T., Jr.; Patterson, John M.

    1984-01-01

    Literature on analytical methods related to the functional groups of 17 chemical compounds is reviewed. These compounds include acids, acid azides, alcohols, aldehydes, ketones, amino acids, aromatic hydrocarbons, carbodiimides, carbohydrates, ethers, nitro compounds, nitrosamines, organometallic compounds, peroxides, phenols, silicon compounds,…

  18. Functional group analysis

    SciTech Connect

    Smith, W.T. Jr.; Patterson, J.M.

    1986-04-01

    Analytical methods for functional group analysis are reviewed. Literature reviewed is from the period of December 1983 through November 1985 and presents methods for determining the following compounds: acids, acid halides, active hydrogen, alcohols, aldehydes, ketones, amides, amines, amino acids, anhydrides, aromatic hydrocarbons, azo compounds, carbohydrates, chloramines, esters, ethers, halogen compounds, hydrazines, isothiocyanates, nitro compounds, nitroso compounds, organometallic compounds, oxiranes, peroxides, phenols, phosphorus compounds, quinones, silicon compounds, sulfates, sulfonyl chlorides, thioamides, thiols, and thiosemicarbazones. 150 references.

  19. Cluster functional renormalization group

    NASA Astrophysics Data System (ADS)

    Reuther, Johannes; Thomale, Ronny

    2014-01-01

    Functional renormalization group (FRG) has become a diverse and powerful tool to derive effective low-energy scattering vertices of interacting many-body systems. Starting from a free expansion point of the action, the flow of the RG parameter Λ allows us to trace the evolution of the effective one- and two-particle vertices towards low energies by taking into account the vertex corrections between all parquet channels in an unbiased fashion. In this work, we generalize the expansion point at which the diagrammatic resummation procedure is initiated from a free UV limit to a cluster product state. We formulate a cluster FRG scheme where the noninteracting building blocks (i.e., decoupled spin clusters) are treated exactly, and the intercluster couplings are addressed via RG. As a benchmark study, we apply our cluster FRG scheme to the spin-1/2 bilayer Heisenberg model (BHM) on a square lattice where the neighboring sites in the two layers form the individual two-site clusters. Comparing with existing numerical evidence for the BHM, we obtain reasonable findings for the spin susceptibility, the spin-triplet excitation energy, and quasiparticle weight even in coupling regimes close to antiferromagnetic order. The concept of cluster FRG promises applications to a large class of interacting electron systems.

  20. Optimization and application of atmospheric pressure chemical and photoionization hydrogen-deuterium exchange mass spectrometry for speciation of oxygen-containing compounds.

    PubMed

    Acter, Thamina; Kim, Donghwi; Ahmed, Arif; Jin, Jang Mi; Yim, Un Hyuk; Shim, Won Joon; Kim, Young Hwan; Kim, Sunghwan

    2016-05-01

    This paper presents a detailed investigation of the feasibility of optimized positive and negative atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) and atmospheric pressure photoionization (APPI) MS coupled to hydrogen-deuterium exchange (HDX) for structural assignment of diverse oxygen-containing compounds. The important parameters for optimization of HDX MS were characterized. The optimized techniques employed in the positive and negative modes showed satisfactory HDX product ions for the model compounds when dichloromethane and toluene were employed as a co-solvent in APCI- and APPI-HDX, respectively. The evaluation of the mass spectra obtained from 38 oxygen-containing compounds demonstrated that the extent of the HDX of the ions was structure-dependent. The combination of information provided by different ionization techniques could be used for better speciation of oxygen-containing compounds. For example, (+) APPI-HDX is sensitive to compounds with alcohol, ketone, or aldehyde substituents, while (-) APPI-HDX is sensitive to compounds with carboxylic functional groups. In addition, the compounds with alcohol can be distinguished from other compounds by the presence of exchanged peaks. The combined information was applied to study chemical compositions of degraded oils. The HDX pattern, double bond equivalent (DBE) distribution, and previously reported oxidation products were combined to predict structures of the compounds produced from oxidation of oil. Overall, this study shows that APCI- and APPI-HDX MS are useful experimental techniques that can be applied for the structural analysis of oxygen-containing compounds.

  1. Optimization and application of atmospheric pressure chemical and photoionization hydrogen-deuterium exchange mass spectrometry for speciation of oxygen-containing compounds.

    PubMed

    Acter, Thamina; Kim, Donghwi; Ahmed, Arif; Jin, Jang Mi; Yim, Un Hyuk; Shim, Won Joon; Kim, Young Hwan; Kim, Sunghwan

    2016-05-01

    This paper presents a detailed investigation of the feasibility of optimized positive and negative atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) and atmospheric pressure photoionization (APPI) MS coupled to hydrogen-deuterium exchange (HDX) for structural assignment of diverse oxygen-containing compounds. The important parameters for optimization of HDX MS were characterized. The optimized techniques employed in the positive and negative modes showed satisfactory HDX product ions for the model compounds when dichloromethane and toluene were employed as a co-solvent in APCI- and APPI-HDX, respectively. The evaluation of the mass spectra obtained from 38 oxygen-containing compounds demonstrated that the extent of the HDX of the ions was structure-dependent. The combination of information provided by different ionization techniques could be used for better speciation of oxygen-containing compounds. For example, (+) APPI-HDX is sensitive to compounds with alcohol, ketone, or aldehyde substituents, while (-) APPI-HDX is sensitive to compounds with carboxylic functional groups. In addition, the compounds with alcohol can be distinguished from other compounds by the presence of exchanged peaks. The combined information was applied to study chemical compositions of degraded oils. The HDX pattern, double bond equivalent (DBE) distribution, and previously reported oxidation products were combined to predict structures of the compounds produced from oxidation of oil. Overall, this study shows that APCI- and APPI-HDX MS are useful experimental techniques that can be applied for the structural analysis of oxygen-containing compounds. PMID:26898203

  2. Functional Group Analysis.

    ERIC Educational Resources Information Center

    Smith, Walter T., Jr.; Patterson, John M.

    1980-01-01

    Discusses analytical methods selected from current research articles. Groups information by topics of general interest, including acids, aldehydes and ketones, nitro compounds, phenols, and thiols. Cites 97 references. (CS)

  3. Learning the Functional Groups: Keys to Success.

    ERIC Educational Resources Information Center

    Byrd, Shannon; Hildreth, David P.

    2001-01-01

    Points out the difficulties students have when they are expected to learn functional groups, which are frameworks for chemical and physical properties of molecules. Presents a classification key for functional groups categorized by 10 common functional groups. (YDS)

  4. Comparison of functional group selective ion-molecule reactions of trimethyl borate in different ion trap mass spectrometers

    SciTech Connect

    Habicht, S C; Vinueza, Nelson R; Amundson, Lucas M; Kenttämaa, Hilkka I

    2011-02-01

    We report here a comparison of the use of diagnostic ion–molecule reactions for the identification of oxygen-containing functional groups in Fourier-transform ion cyclotron resonance (FTICR) and linear quadrupole ion trap (LQIT) mass spectrometers. The ultimate goal of this research is to be able to identify functionalities in previously unknown analytes by using many different types of mass spectrometers. Previous work has focused on the reactions of various boron reagents with protonated oxygen-containing analytes in FTICR mass spectrometers. By using a LQIT modified to allow the introduction of neutral reagents into the helium buffer gas, this methodology has been successfully implemented to this type of an ion trap instrument. The products obtained from the reactions of trimethyl borate (TMB) with various protonated analytes are compared for the two instruments. Finally, the ability to integrate these reactions into LC-MS experiments on the LQIT is demonstrated.

  5. Thermal stability of uranyl complexes with neutral oxygen-containing organic bases

    SciTech Connect

    Kobets, L.V.

    1987-03-01

    The thermal stability of uranyl chloride, nitrate, and oxalate with a series of neutral oxygen-containing organic ligands is discussed. It was found that the temperatures of removal of chlorine are higher than the stripping of the first molecule of the base in complexes UO/sub 2/Cl/sub 2/ x 2L. This is an indication of greater strength of the bonds of the Cl/sup -/ ions to the uranyl group in comparison with the investigated bases. It was shown that the temperatures of removal of a mole of neutral ligands depend little on the nature of the anions and exhibit a correlation with the donor capacity of the bases: Ac < TBP < DMFA similarly ordered DMSO < TBPO similarly ordered PyO. The chemistry of the decomposition of the complexes and the strength of the binding of the acido- and neutral ligands in them are discussed.

  6. Functional group diversity in dendrimers.

    PubMed

    Sivanandan, Kulandaivelu; Vutukuri, Dharmarao; Thayumanavan, S

    2002-10-17

    [structure: see text] A methodology for synthesizing dendrons with different peripheral functionalities is described. The benzyl ether-based dendrons reported here were synthesized using allyl and methoxymethyl ether-based protection-deprotection strategies.

  7. A Functional Analytic Approach to Group Psychotherapy

    ERIC Educational Resources Information Center

    Vandenberghe, Luc

    2009-01-01

    This article provides a particular view on the use of Functional Analytical Psychotherapy (FAP) in a group therapy format. This view is based on the author's experiences as a supervisor of Functional Analytical Psychotherapy Groups, including groups for women with depression and groups for chronic pain patients. The contexts in which this approach…

  8. Reactions of oxygen-containing molecules on transition metal carbides: Surface science insight into potential applications in catalysis and electrocatalysis

    NASA Astrophysics Data System (ADS)

    Stottlemyer, Alan L.; Kelly, Thomas G.; Meng, Qinghe; Chen, Jingguang G.

    2012-09-01

    Historically the interest in the catalytic properties of transition metal carbides (TMC) has been inspired by their "Pt-like" properties in the transformation reactions of hydrocarbon molecules. Recent studies, however, have revealed that the reaction pathways of oxygen-containing molecules are significantly different between TMCs and Pt-group metals. Nonetheless, TMCs demonstrate intriguing catalytic properties toward oxygen-containing molecules, either as the catalyst or as the catalytically active substrate to support metal catalysts, in several important catalytic and electrocatalytic applications, including water electrolysis, alcohol electrooxidation, biomass conversion, and water gas shift reactions. In the current review we provide a summary of theoretical and experimental studies of the interaction of TMC surfaces with oxygen-containing molecules, including both inorganic (O2, H2O, CO and CO2) and organic (alcohols, aldehydes, acids and esters) molecules. We will discuss the general trends in the reaction pathways, as well as future research opportunities in surface science studies that would facilitate the utilization of TMCs as catalysts and electrocatalysts.

  9. Reactions of oxygen-containing molecules on transition metal carbides: Surface science insight into potential applications in catalysis and electrocatalysis

    NASA Astrophysics Data System (ADS)

    Stottlemyer, Alan L.; Kelly, Thomas G.; Meng, Qinghe; Chen, Jingguang G.

    2012-09-01

    Historically the interest in the catalytic properties of transition metal carbides (TMC) has been inspired by their “Pt-like” properties in the transformation reactions of hydrocarbon molecules. Recent studies, however, have revealed that the reaction pathways of oxygen-containing molecules are significantly different between TMCs and Pt-group metals. Nonetheless, TMCs demonstrate intriguing catalytic properties toward oxygen-containing molecules, either as the catalyst or as the catalytically active substrate to support metal catalysts, in several important catalytic and electrocatalytic applications, including water electrolysis, alcohol electrooxidation, biomass conversion, and water gas shift reactions. In the current review we provide a summary of theoretical and experimental studies of the interaction of TMC surfaces with oxygen-containing molecules, including both inorganic (O2, H2O, CO and CO2) and organic (alcohols, aldehydes, acids and esters) molecules. We will discuss the general trends in the reaction pathways, as well as future research opportunities in surface science studies that would facilitate the utilization of TMCs as catalysts and electrocatalysts.

  10. Comparatively studying the ultrasound present in a mild two-stage approach on the content of functional groups in modified MWCNT

    NASA Astrophysics Data System (ADS)

    Tian, Run; Liang, Shaolei; Li, Guangfen; Zhang, Yanxia; Shi, Le

    2016-04-01

    A two-stage approach assisted with ultrasound for oxidation of multiwalled carbon nanotubes (MWCNT) with ultra-high content of functional groups was utilized. The effect of ultrasound on the content of functional groups of the modified MWCNTs from different stages was analyzed by FE-SEM, HR-TEM, FTIR, Raman, TGA, XPS and triple double-backward titration method. The results confirm that more oxygen-containing functional groups were grafted on MWCNT with little damage to the structure integrity of nanotubes. The particle size distribution and the dispersion photography of MWCNTs in water and in ethanol further show a better dispersion of modified MWCNTs in polar solvent.

  11. Relating Functional Groups to the Periodic Table

    ERIC Educational Resources Information Center

    Struyf, Jef

    2009-01-01

    An introduction to organic chemistry functional groups and their ionic variants is presented. Functional groups are ordered by the position of their specific (hetero) atom in the periodic table. Lewis structures are compared with their corresponding condensed formulas. (Contains 5 tables.)

  12. Methods for separating oxygen from oxygen-containing gases

    DOEpatents

    Mackay, Richard; Schwartz, Michael; Sammells, Anthony F.

    2000-01-01

    This invention provides mixed conducting metal oxides particularly useful for the manufacture of catalytic membranes for gas-phase oxygen separation processes. The materials of this invention have the general formula: A.sub.x A'.sub.x A".sub.2-(x+x') B.sub.y B'.sub.y B".sub.2-(y+y') O.sub.5+z ; where x and x' are greater than 0; y and y' are greater than 0; x+x' is less than or equal to 2; y+y' is less than or equal to 2; z is a number that makes the metal oxide charge neutral; A is an element selected from the f block lanthanide elements; A' is an element selected from Be, Mg, Ca, Sr, Ba and Ra; A" is an element selected from the f block lanthanides or Be, Mg, Ca, Sr, Ba and Ra; B is an element selected from the group consisting of Al, Ga, In or mixtures thereof; and B' and B" are different elements and are independently selected from the group of elements Mg or the d-block transition elements. The invention also provides methods for oxygen separation and oxygen enrichment of oxygen deficient gases which employ mixed conducting metal oxides of the above formula. Examples of the materials used for the preparation of the membrane include A.sub.x Sr.sub.x' B.sub.y Fe.sub.y' Co.sub.2-(y+y') O.sub.5+z, where x is about 0.3 to about 0.5, x' is about 1.5 to about 1.7, y is 0.6, y' is between about 1.0 and 1.4 and B is Ga or Al.

  13. Vapor pressures and thermodynamics of oxygen-containing polycyclic aromatic hydrocarbons measured using Knudsen effusion

    SciTech Connect

    Goldfarb, J.L.; Suuberg, E.M.

    2008-06-15

    Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives (OPAHs) are ubiquitous environmental pollutants resulting from the incomplete combustion of coal and fossil fuels. Their vapor pressures are key thermodynamic data essential for modeling fate and transport within the environment. The present study involved nine PAHs containing oxygen heteroatoms, including aldehyde, carboxyl, and nitro groups, specifically 2-nitrofluorene, 9-fluorenecarboxylic acid, 2-fluorenecarboxaldehyde, 2-anthracenecarboxylic acid, 9-anthracenecarboxylic acid, 9-anthraldehyde, 1-nitropyrene, 1-pyrenecarboxaldehyde, and 1-bromo-2-naphthoic acid. The vapor pressures of these compounds, with molecular weights ranging from 194 to 251 g/mol, were measured using the isothermal Knudsen effusion technique in the temperature range of 329 to 421 K. The corresponding enthalpies of sublimation, calculated via the Clausius-Clapeyron equation, are compared to parent, nonoxygenated PAH compound data to determine the effect of the addition of these oxygen-containing heteroatoms. As expected, the addition of -CHO, -COOH, and -NO{sub 2} groups onto these PAHs increases the enthalpy of sublimation and decreases the vapor pressure as compared to the parent PAH; the position of substitution also plays a significant role in determining the vapor pressure of these OPAHs.

  14. Vapor Pressures and Thermodynamics of Oxygen-Containing Polycyclic Aromatic Hydrocarbons Measured Using Knudsen Effusion

    PubMed Central

    Goldfarb, Jillian L.

    2013-01-01

    Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives (OPAHs) are ubiquitous environmental pollutants resulting from the incomplete combustion of coal and fossil fuels. Their vapor pressures are key thermodynamic data essential for modeling fate and transport within the environment. The present study involved nine PAHs containing oxygen heteroatoms, including aldehyde, carboxyl and nitro groups, specifically: 2-nitrofluorene; 9-fluorenecarboxylic acid; 2-fluorenecarboxaldehyde; 2-anthracenecarboxylic acid; 9-anthracenecarboxylic acid; 9-anthraldehyde; 1-nitropyrene; 1-pyrenecarboxaldehyde and 1-bromo-2-naphthoic acid. The vapor pressures of these compounds, with molecular weights ranging from 194 to 251 grams per mole, were measured using the isothermal Knudsen effusion technique in the temperature range of 329 to 421. The corresponding enthalpies of sublimation, calculated via the Clausius-Clapeyron equation, are compared to parent, non-oxygenated PAH compound data to determine the effect of the addition of these oxygen-containing heteroatoms. As expected, the addition of –CHO,–COOH, and –NO2 groups onto these PAHs increases the enthalpy of sublimation and decreases the vapor pressure as compared to the parent PAH; the position of substitution also plays a significant role in determining the vapor pressure of these OPAHs. PMID:18220445

  15. Vapor pressures and thermodynamics of oxygen-containing polycyclic aromatic hydrocarbons measured using Knudsen effusion.

    PubMed

    Goldfarb, Jillian L; Suuberg, Eric M

    2008-06-01

    Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives (OPAHs) are ubiquitous environmental pollutants resulting from the incomplete combustion of coal and fossil fuels. Their vapor pressures are key thermodynamic data essential for modeling fate and transport within the environment. The present study involved nine PAHs containing oxygen heteroatoms, including aldehyde, carboxyl, and nitro groups, specifically 2-nitrofluorene, 9-fluorenecarboxylic acid, 2-fluorenecarboxaldehyde, 2-anthracenecarboxylic acid, 9-anthracenecarboxylic acid, 9-anthraldehyde, 1-nitropyrene, 1-pyrenecarboxaldehyde, and 1-bromo-2-naphthoic acid. The vapor pressures of these compounds, with molecular weights ranging from 194 to 251 g/mol, were measured using the isothermal Knudsen effusion technique in the temperature range of 329 to 421 K. The corresponding enthalpies of sublimation, calculated via the Clausius-Clapeyron equation, are compared to parent, nonoxygenated PAH compound data to determine the effect of the addition of these oxygen-containing heteroatoms. As expected, the addition of -CHO, -COOH, and -NO(2) groups onto these PAHs increases the enthalpy of sublimation and decreases the vapor pressure as compared to the parent PAH; the position of substitution also plays a significant role in determining the vapor pressure of these OPAHs. PMID:18220445

  16. Organic Functional Group Playing Card Deck

    NASA Astrophysics Data System (ADS)

    Welsh, Michael J.

    2003-04-01

    The recognition and identification of organic functional groups, while essential for chemistry and biology majors, is also very useful for non-science majors in the study of molecules in art and life. In order to make this task more palatable for the non-science major (art and communications students), the images of a traditional playing deck of cards (heart, spade, diamond, and club) have been replaced with four representations of common organic functional groups. The hierarchy rules for naming two groups in a molecule is loosely incorporated to represent the sequence (King, Queen, Jack, ?, Ace) of the deck. Students practice recognizing and identifying organic groups by playing simple card games of "Old Maid" and "Go Fish". To play games like "Poker" or "Gin", a student must not only recognize the functional groups, but also master a naming hierarchy for the organic groups.

  17. Identifying copepod functional groups from species functional traits

    PubMed Central

    Benedetti, Fabio; Gasparini, Stéphane; Ayata, Sakina-Dorothée

    2016-01-01

    We gathered information on the functional traits of the most representative copepod species in the Mediterranean Sea. Our database includes 191 species described by 7 traits encompassing diverse ecological functions: minimal and maximal body length, trophic group, feeding type, spawning strategy, diel vertical migration and vertical habitat. Cluster analysis in the functional trait space revealed that Mediterranean copepods can be separated into groups with distinct ecological roles. PMID:26811565

  18. Interaction network among functional drug groups

    PubMed Central

    2013-01-01

    Background More attention has been being paid to combinatorial effects of drugs to treat complex diseases or to avoid adverse combinations of drug cocktail. Although drug interaction information has been increasingly accumulated, a novel approach like network-based method is needed to analyse that information systematically and intuitively Results Beyond focussing on drug-drug interactions, we examined interactions between functional drug groups. In this work, functional drug groups were defined based on the Anatomical Therapeutic Chemical (ATC) Classification System. We defined criteria whether two functional drug groups are related. Then we constructed the interaction network of drug groups. The resulting network provides intuitive interpretations. We further constructed another network based on interaction sharing ratio of the first network. Subsequent analysis of the networks showed that some features of drugs can be well described by this kind of interaction even for the case of structurally dissimilar drugs. Conclusion Our networks in this work provide intuitive insights into interactions among drug groups rather than those among single drugs. In addition, information on these interactions can be used as a useful source to describe mechanisms and features of drugs. PMID:24555875

  19. Influence of surface functionalization via chemical oxidation on the properties of carbon nanotubes.

    PubMed

    Chen, Jiuling; Chen, Qinghai; Ma, Qing

    2012-03-15

    The surface of carbon nanotubes (CNTs) was functionalized in different chemical oxidants, hydrogen peroxide, mixed concentrated HNO(3)/H(2)SO(4) and acidic KMnO(4) solution. The influences on the properties of CNTs were systematically investigated, such as the structure, the kinds and the contents of the formed surface oxygen-containing functional groups, the pH(PZC) values and the surface hydrophilicity using XRD, HREM, FTIR and chemical titration. The results show that the kinds and the contents of the surface oxygen-containing groups are dependent on the functionalization methods. The formation of the oxygen-containing groups can decrease pH(PZC) values and improve surface hydrophilicity of CNTs. The dispersion of the supported Pd-Pt particles on the functionalized CNTs and their catalytic activity in the profile reaction of naphthalene hydrogenation to tetralin are both promoted due to the presence of these oxygen-containing groups. PMID:22280791

  20. The circular velocity function of group galaxies

    SciTech Connect

    Abramson, Louis E.; Williams, Rik J.; Benson, Andrew J.; Kollmeier, Juna A.; Mulchaey, John S.

    2014-09-20

    A robust prediction of ΛCDM cosmology is the halo circular velocity function (CVF), a dynamical cousin of the halo mass function. The correspondence between theoretical and observed CVFs is uncertain, however: cluster galaxies are reported to exhibit a power-law CVF consistent with N-body simulations, but that of the field is distinctly Schechter-like, flattened compared to ΛCDM expectations at circular velocities v {sub c} ≲ 200 km s{sup –1}. Groups offer a powerful probe of the role environment plays in this discrepancy as they bridge the field and clusters. Here, we construct the CVF for a large, mass- and multiplicity-complete sample of group galaxies from the Sloan Digital Sky Survey. Using independent photometric v {sub c} estimators, we find no transition from field to ΛCDM-shaped CVF above v {sub c} = 50 km s{sup –1} as a function of group halo mass. All groups with 12.4 ≲ log M {sub halo}/M {sub ☉} ≲ 15.1 (Local Group analogs to rich clusters) display similar Schechter-like CVFs marginally suppressed at low v {sub c} compared to that of the field. Conversely, some agreement with N-body results emerges for samples saturated with late-type galaxies, with isolated late-types displaying a CVF similar in shape to ΛCDM predictions. We conclude that the flattening of the low-v {sub c} slope in groups is due to their depressed late-type fractions—environment affecting the CVF only to the extent that it correlates with this quantity—and that previous cluster analyses may suffer from interloper contamination. These results serve as useful benchmarks for cosmological simulations of galaxy formation.

  1. Toward Relatively General and Accurate Quantum Chemical Predictions of Solid-State 17O NMR Chemical Shifts in Various Biologically Relevant Oxygen-containing Compounds

    PubMed Central

    Rorick, Amber; Michael, Matthew A.; Yang, Liu; Zhang, Yong

    2015-01-01

    Oxygen is an important element in most biologically significant molecules and experimental solid-state 17O NMR studies have provided numerous useful structural probes to study these systems. However, computational predictions of solid-state 17O NMR chemical shift tensor properties are still challenging in many cases and in particular each of the prior computational work is basically limited to one type of oxygen-containing systems. This work provides the first systematic study of the effects of geometry refinement, method and basis sets for metal and non-metal elements in both geometry optimization and NMR property calculations of some biologically relevant oxygen-containing compounds with a good variety of XO bonding groups, X= H, C, N, P, and metal. The experimental range studied is of 1455 ppm, a major part of the reported 17O NMR chemical shifts in organic and organometallic compounds. A number of computational factors towards relatively general and accurate predictions of 17O NMR chemical shifts were studied to provide helpful and detailed suggestions for future work. For the studied various kinds of oxygen-containing compounds, the best computational approach results in a theory-versus-experiment correlation coefficient R2 of 0.9880 and mean absolute deviation of 13 ppm (1.9% of the experimental range) for isotropic NMR shifts and R2 of 0.9926 for all shift tensor properties. These results shall facilitate future computational studies of 17O NMR chemical shifts in many biologically relevant systems, and the high accuracy may also help refinement and determination of active-site structures of some oxygen-containing substrate bound proteins. PMID:26274812

  2. Toward Relatively General and Accurate Quantum Chemical Predictions of Solid-State (17)O NMR Chemical Shifts in Various Biologically Relevant Oxygen-Containing Compounds.

    PubMed

    Rorick, Amber; Michael, Matthew A; Yang, Liu; Zhang, Yong

    2015-09-01

    Oxygen is an important element in most biologically significant molecules, and experimental solid-state (17)O NMR studies have provided numerous useful structural probes to study these systems. However, computational predictions of solid-state (17)O NMR chemical shift tensor properties are still challenging in many cases, and in particular, each of the prior computational works is basically limited to one type of oxygen-containing system. This work provides the first systematic study of the effects of geometry refinement, method, and basis sets for metal and nonmetal elements in both geometry optimization and NMR property calculations of some biologically relevant oxygen-containing compounds with a good variety of XO bonding groups (X = H, C, N, P, and metal). The experimental range studied is of 1455 ppm, a major part of the reported (17)O NMR chemical shifts in organic and organometallic compounds. A number of computational factors toward relatively general and accurate predictions of (17)O NMR chemical shifts were studied to provide helpful and detailed suggestions for future work. For the studied kinds of oxygen-containing compounds, the best computational approach results in a theory-versus-experiment correlation coefficient (R(2)) value of 0.9880 and a mean absolute deviation of 13 ppm (1.9% of the experimental range) for isotropic NMR shifts and an R(2) value of 0.9926 for all shift-tensor properties. These results shall facilitate future computational studies of (17)O NMR chemical shifts in many biologically relevant systems, and the high accuracy may also help the refinement and determination of active-site structures of some oxygen-containing substrate-bound proteins.

  3. Preconversion catalytic deoxygenation of phenolic functional groups

    SciTech Connect

    Kubiak, C.P.

    1991-01-01

    The deoxygenation of phenols is a conceptually simple, but unusually difficult chemical transformation to achieve. Aryl carbon-oxygen bond cleavage is a chemical transformation of importance in coal liquefaction and the upgrading of coal liquids as well as in the synthesis of natural products. This proposed research offers the possibility of effecting the selective catalytic deoxygenation of phenolic functional groups using CO. A program of research for the catalytic deoxygenation of phenols, via a low energy mechanistic pathway that is based on the use of the CO/CO{sub 2} couple to remove phenolic oxygen atoms, is underway. We are focusing on systems which have significant promise as catalysts: Ir(triphos)OPh, (Pt(triphos)OPh){sup +} and Rh(triphos)OPh. Our studies of phenol deoxygenation focus on monitoring the reactions for the elementary processes upon which catalytic activity will depend: CO insertion into M-OPh bonds, CO{sub 2} elimination from aryloxy carbonyls {l brace}M-C(O)-O-Ph{r brace}, followed by formation of a coordinated benzyne intermediate.

  4. Transition metal carbides, nitrides and borides, and their oxygen containing analogs useful as water gas shift catalysts

    DOEpatents

    Thompson, Levi T.; Patt, Jeremy; Moon, Dong Ju; Phillips, Cory

    2003-09-23

    Mono- and bimetallic transition metal carbides, nitrides and borides, and their oxygen containing analogs (e.g. oxycarbides) for use as water gas shift catalysts are described. In a preferred embodiment, the catalysts have the general formula of M1.sub.A M2.sub.B Z.sub.C O.sub.D, wherein M1 is selected from the group consisting of Mo, W, and combinations thereof; M2 is selected from the group consisting of Fe, Ni, Cu, Co, and combinations thereof; Z is selected from the group consisting of carbon, nitrogen, boron, and combinations thereof; A is an integer; B is 0 or an integer greater than 0; C is an integer; O is oxygen; and D is 0 or an integer greater than 0. The catalysts exhibit good reactivity, stability, and sulfur tolerance, as compared to conventional water shift gas catalysts. These catalysts hold promise for use in conjunction with proton exchange membrane fuel cell powered systems.

  5. Functional group diversity increases with modularity in complex food webs.

    PubMed

    Montoya, D; Yallop, M L; Memmott, J

    2015-01-01

    Biodiversity increases the ability of ecosystems to provide multiple functions. Most studies report a positive relationship between species richness and the number of ecosystem functions. However, it is not known whether the number of functional groups is related to the structure of the underlying species interaction network. Here we present food web data from 115 salt marsh islands and show that network structure is associated with the number of functional groups present. Functional group diversity is heterogeneously distributed across spatial scales, with some islands hosting more functional groups than others. Functional groups form modules within the community so that food webs with more modular architectures have more functional group diversity. Further, in communities with different interaction types, modularity can be seen as the multifunctional equivalent of trophic complementarity. Collectively, these findings reveal spatial heterogeneity in the number of functional groups that emerges from patterns in the structure of the food web.

  6. Functional group diversity increases with modularity in complex food webs

    PubMed Central

    Montoya, D.; Yallop, M.L.; Memmott, J.

    2015-01-01

    Biodiversity increases the ability of ecosystems to provide multiple functions. Most studies report a positive relationship between species richness and the number of ecosystem functions. However, it is not known whether the number of functional groups is related to the structure of the underlying species interaction network. Here we present food web data from 115 salt marsh islands and show that network structure is associated with the number of functional groups present. Functional group diversity is heterogeneously distributed across spatial scales, with some islands hosting more functional groups than others. Functional groups form modules within the community so that food webs with more modular architectures have more functional group diversity. Further, in communities with different interaction types, modularity can be seen as the multifunctional equivalent of trophic complementarity. Collectively, these findings reveal spatial heterogeneity in the number of functional groups that emerges from patterns in the structure of the food web. PMID:26059871

  7. Modifications of chemical functional groups of Pandanus amaryllifolius Roxb and its effect towards biosorption of heavy metals

    SciTech Connect

    Abdullah, Mohd Zamri Ismail, Siti Salwa

    2015-07-22

    The utilization of non-living biomass as an alternative biosorbent for heavy metal removal has gain a tremendous consideration through the years. Pandanus amaryllifolius Roxb or pandan leaves, which is widely used as food additives in the South East Asia region, has been selected for its viability in the said effort due to the presence of chemical functional groups on its cellular network that enables the sorption to occur. In order to elucidate the possible mechanisms participated during the heavy metal removal process, the biosorbent undergone a series of modification techniques to alter the chemical functional groups present on its constituent. From the outcome of the chemically-modified biosorbent being subjected to the contact with metal cations, nitrogen- and oxygen-containing groups present on the biosorbent are believed to be responsible for the metal uptake to occur through complexation mechanism. Modifying amine groups causes 14% reduction of Cu(II) uptake, whereas removing protein element increases the uptake to 26% as compared to the unmodified biosorbent. Also, scanning electron micrographs further suggested that the adsorption mechanism could perform in parallel, as attributed to the evidence of porous structure throughout the biosorbent fibrous nature.

  8. Modifications of chemical functional groups of Pandanus amaryllifolius Roxb and its effect towards biosorption of heavy metals

    NASA Astrophysics Data System (ADS)

    Abdullah, Mohd. Zamri; Ismail, Siti Salwa

    2015-07-01

    The utilization of non-living biomass as an alternative biosorbent for heavy metal removal has gain a tremendous consideration through the years. Pandanus amaryllifolius Roxb or pandan leaves, which is widely used as food additives in the South East Asia region, has been selected for its viability in the said effort due to the presence of chemical functional groups on its cellular network that enables the sorption to occur. In order to elucidate the possible mechanisms participated during the heavy metal removal process, the biosorbent undergone a series of modification techniques to alter the chemical functional groups present on its constituent. From the outcome of the chemically-modified biosorbent being subjected to the contact with metal cations, nitrogen- and oxygen-containing groups present on the biosorbent are believed to be responsible for the metal uptake to occur through complexation mechanism. Modifying amine groups causes 14% reduction of Cu(II) uptake, whereas removing protein element increases the uptake to 26% as compared to the unmodified biosorbent. Also, scanning electron micrographs further suggested that the adsorption mechanism could perform in parallel, as attributed to the evidence of porous structure throughout the biosorbent fibrous nature.

  9. Preconversion catalytic deoxygenation of phenolic functional groups

    SciTech Connect

    Kubiak, C.P.

    1990-01-01

    The deoxygenation of phenols is a conceptually simple, but unusually difficult chemical transformation of importance in organic synthesis and commercial coal liquefaction. The phenolic C-O bond energy of 103 kcal/mol is as strong as a benzene C-H bond and over 10 kcal/mol stronger than the C-O bonds of methanol and ethanol. The deoxygenation of phenols by CO is a viable process. metallolactones, created via late transition metal orthometallation of aryloxycarbonyl ligands, may provide the essential low energy pathway for elimination of CO{sub 2}, formation of a benzyne hydride intermediate, and thereby formation of the phenyl group. In the present Pt(OAr){sub 2}(dpps) system the phenyl group produced by phenol deoxygenation is eliminated with an aryloxycarbonyl ligand to yield phenylbenzoates. For this reason we are focusing our ongoing efforts on systems which contain one aryloxide, thus removing the possibility of reductive elimination of the phenyl group prior to elimination of free arenes.

  10. Plant for producing an oxygen-containing additive as an ecologically beneficial component for liquid motor fuels

    DOEpatents

    Siryk, Yury Paul; Balytski, Ivan Peter; Korolyov, Volodymyr George; Klishyn, Olexiy Nick; Lnianiy, Vitaly Nick; Lyakh, Yury Alex; Rogulin, Victor Valery

    2013-04-30

    A plant for producing an oxygen-containing additive for liquid motor fuels comprises an anaerobic fermentation vessel, a gasholder, a system for removal of sulphuretted hydrogen, and a hotwell. The plant further comprises an aerobic fermentation vessel, a device for liquid substance pumping, a device for liquid aeration with an oxygen-containing gas, a removal system of solid mass residue after fermentation, a gas distribution device; a device for heavy gases utilization; a device for ammonia adsorption by water; a liquid-gas mixer; a cavity mixer, a system that serves superficial active and dispersant matters and a cooler; all of these being connected to each other by pipelines. The technical result being the implementation of a process for producing an oxygen containing additive, which after being added to liquid motor fuels, provides an ecologically beneficial component for motor fuels by ensuring the stability of composition fuel properties during long-term storage.

  11. Flotation properties of some oxygen-containing compounds of the acyclic series

    SciTech Connect

    Shreider, E.M.; Para, S.F.; Galanov, M.E.; Trachik, T.L.; Lagutina, L.V.

    1981-01-01

    In the monatomic alcohols series, maximum flotation activity is reached at 6 to 8 carbon atoms in the radical. It was decided to investigate the reagent properties of some other substances containing hydroxyl radicals which have not previously been considered. Oxygen-containing compounds in the acyclic series were examined, including alcohols: I - ethanol, ethylene-glycol, glycerol, pentaerythrytol, D-mannitol; II - dulcitol, D-sorbitol, D-mannitol, xylitol; glycols - monoethyleneglycol, diethyleneglycol, triethyleneglycol, polyethyleneglycol; and ethanolamines - ethanolamine, triethanolamine. The flotation properties of the reagents were determined in a Mekhanobr laboratory flotation machine with a chamber volume of 1.5 liter and an impeller speed of 1800 rpm. The materials tested were the <1 mm size fractions from run-of-plant charge and slurry from the radial thickeners. The samples were first dried and averaged. The pulp density was 200 g/l. The reagent conditions were kept constant throughout (50% of the total added at the start of a test, 25% after 2 min and 25% after 4 min from the start). The reagent additions were 1.0 to 1.4 kg/ton. All of these compounds had a very weak flotation activity.

  12. [2]Rotaxane with multiple functional groups.

    PubMed

    Saha, Subrata; Santra, Saikat; Akhuli, Bidyut; Ghosh, Pradyut

    2014-11-21

    High-yield syntheses of Cu(II)- and Ni(II)-templated [2]pseudorotaxane precursors (CuPRT and NiPRT, respectively) were achieved by threading bis(azide)bis(amide)-2,2'-bipyridine axle into a bis(amide)tris(amine) macrocycle. Single-crystal X-ray structural analysis of CuPRT revealed complete threading of the axle fragment into the wheel cavity, where strong aromatic π-π stacking interactions between two parallel arene moieties of the wheel and the pyridyl unit of axle are operative in addition to metal ion templation. Attachment of a newly developed bulky stopper molecule with a terminal alkyne to CuPRT via a Cu(I)-catalyzed azide-alkyne cycloaddition reaction failed as a result of dethreading of the azide-terminated axle under the reaction conditions. However, the synthesis of a metal-free [2]rotaxane containing triazole with other functionalities in the axle was achieved in ∼45% yield upon coupling between azide-terminated NiPRT and the alkyne-terminated stopper. The [2]rotaxane was characterized by mass spectrometry, 1D and 2D NMR (COSY, DOSY, and ROESY) experiments. Comparative solution-state NMR studies of the [2]rotaxane in its unprotonated and protonated states were carried out to locate the position of the wheel on the axle of the metal-free [2]rotaxane. Furthermore, a variable-temperature (1)H NMR study in DMSO-d6 of [2]rotaxane supported the kinetic inertness of the interlocked structure, where the newly developed stopper prevents dethreading of the 30-membered wheel from the axle.

  13. Wigner functions from the two-dimensional wavelet group.

    PubMed

    Ali, S T; Krasowska, A E; Murenzi, R

    2000-12-01

    Following a general procedure developed previously [Ann. Henri Poincaré 1, 685 (2000)], here we construct Wigner functions on a phase space related to the similitude group in two dimensions. Since the group space in this case is topologically homeomorphic to the phase space in question, the Wigner functions so constructed may also be considered as being functions on the group space itself. Previously the similitude group was used to construct wavelets for two-dimensional image analysis; we discuss here the connection between the wavelet transform and the Wigner function.

  14. Structure and properties of oxygen-containing thin films and bulk MgB2

    NASA Astrophysics Data System (ADS)

    Prikhna, T.; Shapovalov, A.; Goldacker, W.; Eisterer, M.; Kozyrev, A.; Shaternik, V.; Boutko, V.; Gusev, A.; Weber, H. W.; Karpets, M.; Basyuk, T.; Sverdun, V.; Moshchil, V.; Belogolovskiy, M.; Sergienko, N.

    2015-12-01

    A structural Auger spectroscopy study of MgB2 thin (∼140 nm) oxygen-containing polycrystalline films produced by magnetron sputtering and 99% dense MgB2 bulks synthesized at 2 GPa allows us to conclude that jc of MgB2 depends to a high extent on the amount and distribution of oxygen in the material matrix. jc reached 7.8-2.7 MA/cm2 below 1T at 20 K in the films and 0.3-0.9 MA/cm2 (depending on the boron used) in the bulks. The higher jc in MgB2 thin films can be associated with finer oxygen-enriched Mg-B-O inclusions and their higher density in the film structure compared to the bulk. Calculations of the total electron density of states (DOS) in MgB2, MgB1.75O0.25, MgB1.5O0.5 and MgBO showed that all the compounds are conductors with metal-like behaviour. The DOS is even higher in MgB1.5O0 5 than in MgB2 and the binding energy is similar. So, the experimentally found presence of some dissolved oxygen in MgB2 does not contradict its high SC performance. The introduction of a high amount of oxygen into the MgB2 structure does not dramatically reduce the material's Tc and allows obtaining highjc as observed in our MgB2 films and bulks.

  15. Electron scattering cross sections for the modelling of oxygen-containing plasmas*

    NASA Astrophysics Data System (ADS)

    Alves, Luís Lemos; Coche, Philippe; Ridenti, Marco Antonio; Guerra, Vasco

    2016-06-01

    This work proposes a set of electron scattering cross sections for molecular and atomic oxygen, with interest for the modelling of oxygen-containing plasmas. These cross sections, compiled for kinetic energies up to 1 keV, are part of the IST-LISBON database with LXCat, being used as input data to the LoKI (LisbOn KInetics) numerical code. The cross sections for ground-state molecular oxygen describe elastic and inelastic collision mechanisms, the latter including rotational excitations/de-excitations (treated using either a discrete or a continuous approach), vibrational and electronic excitations (including dissociation), dissociative attachment and ionisation. This set yields calculated swarm parameters that reproduce measurements within 5-20% (transport parameters) and within a factor of 2 difference (Townsend coefficients), for reduced electric fields in the range 10-3-103 Td. The cross sections describing the kinetics of atomic oxygen by electron-impact comprise elastic mechanisms, electronic excitation and ionisation from O(3P) ground-state, dissociation of O2(X,a,b) (including dissociative ionisation and attachment) and of O3, and detachment. These cross sections are indirectly validated, together with other elementary data for oxygen, by comparing the densities of O((4S0)3 p 5P) obtained from the self-consistent modelling and from calibrated optical emission spectroscopy diagnostics of microwave-sustained micro-plasmas in dry air (80% N2: 20% O2), produced using a surface-wave excitation (2.45 GHz frequency) within a small radius capillary ( R = 345 μm) at low pressure ( p = 300 Pa). The calculated densities are in good qualitative agreement with measurements, overestimating them by a factor ˜1.5.

  16. Recent advances in hydrotreating of pyrolysis bio-oil and its oxygen-containing model compounds

    SciTech Connect

    Wang, Huamin; Male, Jonathan L.; Wang, Yong

    2013-05-01

    There is considerable world-wide interest in discovering renewable sources of energy that can substitute for fossil fuels. Lignocellulosic biomass, which is the most abundant and inexpensive renewable feedstock on the planet, has a great potential for sustainable production of fuels, chemicals, and carbon-based materials. Fast pyrolysis integrated with hydrotreating is one of the simplest, most cost-effective and most efficient processes to convert lignocellulosic biomass to liquid hydrocarbon fuels for transportation, which has attracted significant attention in recent decades. However, effective hydrotreating of pyrolysis bio-oil presents a daunting challenge to the commercialization of biomass conversion via pyrolysis-hydrotreating. Specifically, development of active, selective, and stable hydrotreating catalysts is the bottleneck due to the poor quality of pyrolysis bio-oil feedstock (high oxygen content, molecular complexity, coking propensity, and corrosiveness). Significant research has been conducted to address the practical issues and provide the fundamental understanding of the hydrotreating/hydrodeoxygenation (HDO) of bio-oils and their oxygen-containing model compounds, including phenolics, furans, and carboxylic acids. A wide range of catalysts have been studied, including conventional Mo-based sulfide catalysts and noble metal catalysts, with the latter being the primary focus of the recent research because of their excellent catalytic performances and no requirement of environmentally unfriendly sulfur. The reaction mechanisms of HDO of model compounds on noble metal catalysts as well as their efficacy for hydrotreating or stabilization of bio-oil have been recently reported. This review provides a survey of the relevant literatures of recent 10 years about the advances in the understanding of the HDO chemistry of bio-oils and their model compounds mainly on noble metal catalysts.

  17. Electron scattering cross sections for the modelling of oxygen-containing plasmas

    NASA Astrophysics Data System (ADS)

    Lemos Alves, Luís; Coche, Philippe; Ridenti, Marco Antonio; Guerra, Vasco

    2016-05-01

    This work proposes a set of electron scattering cross sections for molecular and atomic oxygen, with interest for the modelling of oxygen-containing plasmas. These cross sections, compiled for kinetic energies up to 1 keV, are part of the IST-LISBON database with LXCat, being used as input data to the LoKI (LisbOn KInetics) numerical code. The cross sections for ground-state molecular oxygen describe elastic and inelastic collision mechanisms, the latter including rotational excitations/de-excitations (treated using either a discrete or a continuous approach), vibrational and electronic excitations (including dissociation), dissociative attachment and ionisation. This set yields calculated swarm parameters that reproduce measurements within 5-20% (transport parameters) and within a factor of 2 difference (Townsend coefficients), for reduced electric fields in the range 10-3-103 Td. The cross sections describing the kinetics of atomic oxygen by electron-impact comprise elastic mechanisms, electronic excitation and ionisation from O(3P) ground-state, dissociation of O2(X,a,b) (including dissociative ionisation and attachment) and of O3, and detachment. These cross sections are indirectly validated, together with other elementary data for oxygen, by comparing the densities of O((4S0)3p 5P) obtained from the self-consistent modelling and from calibrated optical emission spectroscopy diagnostics of microwave-sustained micro-plasmas in dry air (80% N2: 20% O2), produced using a surface-wave excitation (2.45 GHz frequency) within a small radius capillary (R = 345 μm) at low pressure (p = 300 Pa). The calculated densities are in good qualitative agreement with measurements, overestimating them by a factor ˜1.5. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  18. Analysis of polycyclic aromatic hydrocarbons and their oxygen-containing derivatives and metabolites in soils.

    PubMed

    Bandowe, Benjamin A Musa; Wilcke, Wolfgang

    2010-01-01

    Although polycyclic aromatic hydrocarbons (PAHs) have been extensively studied, the knowledge of their oxygen-containing derivatives and metabolites (OPAHs) in soils is limited. We modified and tested an existing analytical protocol involving pressurized liquid extraction of soil followed by fractionation of target compounds into PAHs and OPAHs on a silica gel column and gas chromatography/ mass spectrometry-based separation and quantification. Polycyclic aromatic hydrocarbons and carbonyl-OPAHs were quantified directly after separation on silica gel columns, and hydroxyl/carboxyl-OPAHs were quantified after silylation with N,O-bis(trimethylsilyl)trifluoroacetamide. Recoveries between 78 and 97% (relative standard deviation [RSD], 5-12%) were obtained for six carbonyl-OPAHs, whereas 1,2-acenaphthenequinone and 1,4-naphthoquinone showed lower recoveries of 34 and 44% (RSD, 19 and 28%, respectively). Five hydroxyl/carboxyl-OPAHs had recoveries between 36 and 70% (RSD, 13-46%), six others had between 2 and 7% (RSD, 8-25%), and nine were lost in sample preparation. Limits of detection ranged from 0.1 to 1.6 ng g(-1) for OPAHs and from 0.01 to 0.56 ng g(-1) for PAHs. The protocol was applied to soils from a former gasworks site, Berlin, an urban soil from Mainz, both in Germany, and a forest soil from near Manaus, Brazil. The sums of 34 PAH concentrations were 107,000, 3505, and 21 ng g(-1); those of seven carbonyl-OPAHs were 15,690, 170, and 7 ng g(-1); and those of 11 hydroxyl/carboxyl-OPAHs 518, 36, and 16 ng g(-1) for Berlin, Mainz, and Manaus soils, respectively. Several OPAHs were present at concentrations higher than or equal to their parent PAHs, demonstrating the importance of OPAH measurement for the assessment of PAH-related environmental risks. PMID:20830923

  19. Replicating Small Group Research Using the Functional Theory.

    ERIC Educational Resources Information Center

    Cragan, John F.; Wright, David W.

    A replication study tested functional theory utilizing untrained full-fledged groups. One hundred forty undergraduate students who were enrolled in a small group communication course at a large midwestern university participated in small group discussions analyzing a plagiarism case used in an original study by R. Y. Hirokawa. Results indicated…

  20. Functional Analytic Psychotherapy for Interpersonal Process Groups: A Behavioral Application

    ERIC Educational Resources Information Center

    Hoekstra, Renee

    2008-01-01

    This paper is an adaptation of Kohlenberg and Tsai's work, Functional Analytical Psychotherapy (1991), or FAP, to group psychotherapy. This author applied a behavioral rationale for interpersonal process groups by illustrating key points with a hypothetical client. Suggestions are also provided for starting groups, identifying goals, educating…

  1. Enhanced thermal decomposition of nitromethane on functionalized graphene sheets: ab initio molecular dynamics simulations.

    PubMed

    Liu, Li-Min; Car, Roberto; Selloni, Annabella; Dabbs, Daniel M; Aksay, Ilhan A; Yetter, Richard A

    2012-11-21

    The burning rate of the monopropellant nitromethane (NM) has been observed to increase by adding and dispersing small amounts of functionalized graphene sheets (FGSs) in liquid NM. Until now, no plausible mechanisms for FGSs acting as combustion catalysts have been presented. Here, we report ab initio molecular dynamics simulations showing that carbon vacancy defects within the plane of the FGSs, functionalized with oxygen-containing groups, greatly accelerate the thermal decomposition of NM and its derivatives. This occurs through reaction pathways involving the exchange of protons or oxygens between the oxygen-containing functional groups and NM and its derivatives. FGS initiates and promotes the decomposition of the monopropellant and its derivatives, ultimately forming H(2)O, CO(2), and N(2). Concomitantly, oxygen-containing functional groups on the FGSs are consumed and regenerated without significantly changing the FGSs in accordance with experiments indicating that the FGSs are not consumed during combustion. PMID:23101732

  2. Differential Item Functioning Detection across Two Methods of Defining Group Comparisons: Pairwise and Composite Group Comparisons

    ERIC Educational Resources Information Center

    Sari, Halil Ibrahim; Huggins, Anne Corinne

    2015-01-01

    This study compares two methods of defining groups for the detection of differential item functioning (DIF): (a) pairwise comparisons and (b) composite group comparisons. We aim to emphasize and empirically support the notion that the choice of pairwise versus composite group definitions in DIF is a reflection of how one defines fairness in DIF…

  3. Single or functionalized fullerenes interacting with heme group

    NASA Astrophysics Data System (ADS)

    Costa, Wallison Chaves; Diniz, Eduardo Moraes

    2014-09-01

    The heme group is responsible for iron transportation through the bloodstream, where iron participates in redox reactions, electron transfer, gases detection etc. The efficiency of such processes can be reduced if the whole heme molecule or even the iron is somehow altered from its original oxidation state, which can be caused by interactions with nanoparticles as fullerenes. To verify how such particles alter the geometry and electronic structure of heme molecule, here we report first principles calculations based on density functional theory of heme group interacting with single C60 fullerene or with C60 functionalized with small functional groups (-CH3, -COOH, -NH2, -OH). The calculations shown that the system heme + nanoparticle has a different spin state in comparison with heme group if the fullerene is functionalized. Also a functional group can provide a stronger binding between nanoparticle and heme molecule or inhibit the chemical bonding in comparison with single fullerene results. In addition heme molecule loses electrons to the nanoparticles and some systems exhibited a geometry distortion in heme group, depending on the binding energy. Furthermore, one find that such nanoparticles induce a formation of spin up states in heme group. Moreover, there exist modifications in density of states near the Fermi energy. Although of such changes in heme electronic structure and geometry, the iron atom remains in the heme group with the same oxidation state, so that processes that involve the iron might not be affected, only those that depend on the whole heme molecule.

  4. FGO: A novel ontology for identification of ligand functional group

    PubMed Central

    Varadwaj, Pritish Kumar; Lahiri, Tapobrata

    2007-01-01

    Small molecules play crucial role in the modulation of biological functions by interacting with specific macromolecules. Hence small molecule interactions are captured by a variety of experimental methods to estimate and propose correlations between molecular structures to their biological activities. The tremendous expanse in publicly available small molecules is also driving new efforts to better understand interactions involving small molecules particularly in area of drug docking and pharmacogenomics. We have studied and designed a functional group identification system with the associated ontology for it. The functional group identification system can detect the functional group components from given ligand structure with specific coordinate information. Functional group ontology (FGO) proposed by us is a structured classification of chemical functional group which acts as an important source of prior knowledge that may be automatically integrated to support identification, categorization and predictive data analysis tasks. We have used a new annotation method which can be used to construct the original structure from given ontological expression using exact coordinate information. Here, we also discuss about ontology-driven similarity measure of functional groups and uses of such novel ontology for pharmacophore searching and de-novo ligand designing. PMID:18288335

  5. Functional Group and Substructure Searching as a Tool in Metabolomics

    PubMed Central

    Kotera, Masaaki; McDonald, Andrew G.; Boyce, Sinéad; Tipton, Keith F.

    2008-01-01

    Background A direct link between the names and structures of compounds and the functional groups contained within them is important, not only because biochemists frequently rely on literature that uses a free-text format to describe functional groups, but also because metabolic models depend upon the connections between enzymes and substrates being known and appropriately stored in databases. Methodology We have developed a database named “Biochemical Substructure Search Catalogue” (BiSSCat), which contains 489 functional groups, >200,000 compounds and >1,000,000 different computationally constructed substructures, to allow identification of chemical compounds of biological interest. Conclusions This database and its associated web-based search program (http://bisscat.org/) can be used to find compounds containing selected combinations of substructures and functional groups. It can be used to determine possible additional substrates for known enzymes and for putative enzymes found in genome projects. Its applications to enzyme inhibitor design are also discussed. PMID:18253485

  6. Functional Grouping in Residential Homes for People with Intellectual Disabilities.

    ERIC Educational Resources Information Center

    Mansell, Jim; Beadle-Brown, Julie; Macdonald, Susan; Ashman, Bev

    2003-01-01

    The effects of functional grouping of 303 people with intellectual disabilities on care practices in English group homes were investigated. Residents who were non-ambulant were rated as receiving care with less interpersonal warmth and residents with severe challenging behavior were rated as receiving care with less interpersonal warmth and…

  7. Using the Group Presentation to Foster Functional Skills.

    ERIC Educational Resources Information Center

    King, Kim M.

    1990-01-01

    Suggests using group presentations as a method for instructors with large introductory courses to help students gain functional skills and also make the courses more interesting. Provides examples of group presentation projects. States goals of projects as showing how sociology can be used in everyday life and providing a review of the examination…

  8. Background field functional renormalization group for absorbing state phase transitions.

    PubMed

    Buchhold, Michael; Diehl, Sebastian

    2016-07-01

    We present a functional renormalization group approach for the active to inactive phase transition in directed percolation-type systems, in which the transition is approached from the active, finite density phase. By expanding the effective potential for the density field around its minimum, we obtain a background field action functional, which serves as a starting point for the functional renormalization group approach. Due to the presence of the background field, the corresponding nonperturbative flow equations yield remarkably good estimates for the critical exponents of the directed percolation universality class, even in low dimensions. PMID:27575107

  9. Background field functional renormalization group for absorbing state phase transitions

    NASA Astrophysics Data System (ADS)

    Buchhold, Michael; Diehl, Sebastian

    2016-07-01

    We present a functional renormalization group approach for the active to inactive phase transition in directed percolation-type systems, in which the transition is approached from the active, finite density phase. By expanding the effective potential for the density field around its minimum, we obtain a background field action functional, which serves as a starting point for the functional renormalization group approach. Due to the presence of the background field, the corresponding nonperturbative flow equations yield remarkably good estimates for the critical exponents of the directed percolation universality class, even in low dimensions.

  10. Detection of rare functional variants using group ISIS.

    PubMed

    Niu, Yue S; Hao, Ning; An, Lingling

    2011-11-29

    Genome-wide association studies have been firmly established in investigations of the associations between common genetic variants and complex traits or diseases. However, a large portion of complex traits and diseases cannot be explained well by common variants. Detecting rare functional variants becomes a trend and a necessity. Because rare variants have such a small minor allele frequency (e.g., <0.05), detecting functional rare variants is challenging. Group iterative sure independence screening (ISIS), a fast group selection tool, was developed to select important genes and the single-nucleotide polymorphisms within. The performance of the group ISIS and group penalization methods is compared for detecting important genes in the Genetic Analysis Workshop 17 data. The results suggest that the group ISIS is an efficient tool to discover genes and single-nucleotide polymorphisms associated to phenotypes.

  11. Single or functionalized fullerenes interacting with heme group

    SciTech Connect

    Costa, Wallison Chaves; Diniz, Eduardo Moraes

    2014-09-15

    The heme group is responsible for iron transportation through the bloodstream, where iron participates in redox reactions, electron transfer, gases detection etc. The efficiency of such processes can be reduced if the whole heme molecule or even the iron is somehow altered from its original oxidation state, which can be caused by interactions with nanoparticles as fullerenes. To verify how such particles alter the geometry and electronic structure of heme molecule, here we report first principles calculations based on density functional theory of heme group interacting with single C{sub 60} fullerene or with C{sub 60} functionalized with small functional groups (−CH{sub 3}, −COOH, −NH{sub 2}, −OH). The calculations shown that the system heme + nanoparticle has a different spin state in comparison with heme group if the fullerene is functionalized. Also a functional group can provide a stronger binding between nanoparticle and heme molecule or inhibit the chemical bonding in comparison with single fullerene results. In addition heme molecule loses electrons to the nanoparticles and some systems exhibited a geometry distortion in heme group, depending on the binding energy. Furthermore, one find that such nanoparticles induce a formation of spin up states in heme group. Moreover, there exist modifications in density of states near the Fermi energy. Although of such changes in heme electronic structure and geometry, the iron atom remains in the heme group with the same oxidation state, so that processes that involve the iron might not be affected, only those that depend on the whole heme molecule.

  12. Functional Gene Group Summarization by Clustering MEDLINE Abstract Sentences

    PubMed Central

    Yang, Jianji; Cohen, Aaron M.; Hersh, William R.

    2006-01-01

    Tools to automatically summarize functional gene group information from the biomedical literature will help genomics researchers both better interpret gene expression data and understand biological pathways. In this study, we built a system that takes in a set of genes and MEDLINE records and outputs clusters of genes along with summaries of each cluster by sentence extraction from MEDLINE abstracts. Our preliminary use-case evaluation shows that this approach can identify gene clusters similar to manually generated groupings. PMID:17238770

  13. The carbon functional group budget of a peatland

    NASA Astrophysics Data System (ADS)

    Moody, Catherine; Worrall, Fred; Clay, Gareth; Apperley, David

    2016-04-01

    Organic matter samples were taken from each organic matter reservoir and fluvial flux found in a peatland and analysed by elemental analysis for carbon, hydrogen, nitrogen and oxygen content, and by 13C solid state nuclear magnetic resonance (NMR) for functional group composition. The samples analysed were: aboveground, belowground, heather, mosses and sedges, litter layer, four different depths from a peat core, and monthly samples of fluvial particulate and dissolved organic matter. All organic matter samples were taken from a 100% peat catchment within Moor House National Nature Reserve in the North Pennines, UK. The proportion of carbon atoms from each of the eight carbon functional groups (C-alkyl, N-alkyl/methoxyl C, O-alkyl, O2-alkyl/acetal C, aromatic/unsaturated C, phenolic C, aldehyde/ketone C and amide/carboxyl C) from each type of organic matter were combined with an existing carbon budget from the same site, to give a functional group carbon budget. The budget results show that the ecosystem is accumulating N-alkyl/methoxyl C, O-alkyl, O2-alkyl/acetal C and phenolic C groups, but losing C-alkyl, aromatic/unsaturated C, amide/carboxyl C and aldehyde/ketone C. Comparing the functional group compositions between the sampled organic matter pools shows that DOM arises from two distinct sources; from the peat itself and from a vegetation source.

  14. From infinite to two dimensions through the functional renormalization group.

    PubMed

    Taranto, C; Andergassen, S; Bauer, J; Held, K; Katanin, A; Metzner, W; Rohringer, G; Toschi, A

    2014-05-16

    We present a novel scheme for an unbiased, nonperturbative treatment of strongly correlated fermions. The proposed approach combines two of the most successful many-body methods, the dynamical mean field theory and the functional renormalization group. Physically, this allows for a systematic inclusion of nonlocal correlations via the functional renormalization group flow equations, after the local correlations are taken into account nonperturbatively by the dynamical mean field theory. To demonstrate the feasibility of the approach, we present numerical results for the two-dimensional Hubbard model at half filling. PMID:24877952

  15. Species, functional groups, and thresholds in ecological resilience

    USGS Publications Warehouse

    Sundstrom, Shana M.; Allen, Craig R.; Barichievy, Chris

    2012-01-01

    The cross-scale resilience model states that ecological resilience is generated in part from the distribution of functions within and across scales in a system. Resilience is a measure of a system's ability to remain organized around a particular set of mutually reinforcing processes and structures, known as a regime. We define scale as the geographic extent over which a process operates and the frequency with which a process occurs. Species can be categorized into functional groups that are a link between ecosystem processes and structures and ecological resilience. We applied the cross-scale resilience model to avian species in a grassland ecosystem. A species’ morphology is shaped in part by its interaction with ecological structure and pattern, so animal body mass reflects the spatial and temporal distribution of resources. We used the log-transformed rank-ordered body masses of breeding birds associated with grasslands to identify aggregations and discontinuities in the distribution of those body masses. We assessed cross-scale resilience on the basis of 3 metrics: overall number of functional groups, number of functional groups within an aggregation, and the redundancy of functional groups across aggregations. We assessed how the loss of threatened species would affect cross-scale resilience by removing threatened species from the data set and recalculating values of the 3 metrics. We also determined whether more function was retained than expected after the loss of threatened species by comparing observed loss with simulated random loss in a Monte Carlo process. The observed distribution of function compared with the random simulated loss of function indicated that more functionality in the observed data set was retained than expected. On the basis of our results, we believe an ecosystem with a full complement of species can sustain considerable species losses without affecting the distribution of functions within and across aggregations, although

  16. Species, functional groups, and thresholds in ecological resilience.

    PubMed

    Sundstrom, Shana M; Allen, Craig R; Barichievy, Chris

    2012-04-01

    The cross-scale resilience model states that ecological resilience is generated in part from the distribution of functions within and across scales in a system. Resilience is a measure of a system's ability to remain organized around a particular set of mutually reinforcing processes and structures, known as a regime. We define scale as the geographic extent over which a process operates and the frequency with which a process occurs. Species can be categorized into functional groups that are a link between ecosystem processes and structures and ecological resilience. We applied the cross-scale resilience model to avian species in a grassland ecosystem. A species' morphology is shaped in part by its interaction with ecological structure and pattern, so animal body mass reflects the spatial and temporal distribution of resources. We used the log-transformed rank-ordered body masses of breeding birds associated with grasslands to identify aggregations and discontinuities in the distribution of those body masses. We assessed cross-scale resilience on the basis of 3 metrics: overall number of functional groups, number of functional groups within an aggregation, and the redundancy of functional groups across aggregations. We assessed how the loss of threatened species would affect cross-scale resilience by removing threatened species from the data set and recalculating values of the 3 metrics. We also determined whether more function was retained than expected after the loss of threatened species by comparing observed loss with simulated random loss in a Monte Carlo process. The observed distribution of function compared with the random simulated loss of function indicated that more functionality in the observed data set was retained than expected. On the basis of our results, we believe an ecosystem with a full complement of species can sustain considerable species losses without affecting the distribution of functions within and across aggregations, although ecological

  17. Galaxy and Group Baryonic Mass Functions for the RESOLVE Survey

    NASA Astrophysics Data System (ADS)

    Eckert, Kathleen D.; Kannappan, Sheila; Moffett, Amanda J.; Baker, Ashley; Stark, David; Berlind, Andreas A.; Storey-Fisher, Kate; Erickcek, Adrienne L.; Norris, Mark A.; Resolve Team

    2015-01-01

    We present a comparison of the galaxy and group baryonic mass functions for a subvolume of the RESOLVE (Resolved Spectroscopy Of a Local VolumE) survey. RESOLVE occupies A and B semester volumes totaling ~52,000 cubic Mpc, complete in baryonic mass to ~10^9.3 Msun and 10^9.0 Msun respectively, with galaxies and groups ranging in halo mass from 10^11-10^14 Msun. The A semester volume is surrounded by the larger ECO catalog, which lacks complete HI data but occupies ~561,000 cubic Mpc. We define the observed baryonic mass of a galaxy or group to be the sum of its stellar and cold atomic hydrogen components, with the latter inferred indirectly for much of ECO. For groups, we infer the total baryonic mass by summing the observed components of each constituent galaxy and add the likely hot halo gas based on prescriptions from observations and semi-analytic models. We perform subhalo/halo abundance matching between observed galaxies/groups and dark matter simulations, and we compare derived halo properties based on matching on luminosity vs. on observed baryonic mass (or on inferred total baryonic mass for groups). We also present a status update on the galaxy and group velocity functions for these surveys, which will allow for more direct comparison with dark matter simulations. This project was supported by NSF funding for the RESOLVE survey (AST-0955368).

  18. Oxide scales formed on Fe-Cr-Al-based model alloys exposed to oxygen containing molten lead

    NASA Astrophysics Data System (ADS)

    Weisenburger, A.; Jianu, A.; Doyle, S.; Bruns, M.; Fetzer, R.; Heinzel, A.; DelGiacco, M.; An, W.; Müller, G.

    2013-06-01

    Based on the state of the art oxide maps concerning oxidation behavior of Fe-Cr-Al model alloys at 800 and 1000 °C in oxygen atmosphere, ten compositions, belonging to this alloy system, were designed in order to tap the borders of the alumina stability domain, during their exposure to oxygen (10-6 wt.%) containing lead, at 400, 500 and 600 °C. Eight alloys, Fe-6Cr-6Al, Fe-8Cr-6Al, Fe-10Cr-5Al, Fe-14Cr-4Al, Fe-16Cr-4Al, Fe-6Cr-8Al, Fe-10Cr-7Al and Fe-12Cr-5Al, were found to be protected against corrosion in oxygen containing lead, either by a duplex layer (Fe3O4 + (Fe1-x-yCrxAly)3O4) or by (Fe1-x-yCrxAly)3O4, depending on the temperature at which they were exposed. Two alloys namely Fe-12Cr-7Al and Fe-16Cr-6Al were found to form transient aluminas, κ-Al2O3 (at 400 and 500 °C) and θ-Al2O3 (at 600 °C), as protective oxide scale against corrosion in oxygen containing lead. An oxide map illustrating the stability domain of alumina, grown on Fe-Cr-Al alloys when exposed to molten, oxygen containing lead, was drawn. The map includes also additional points, extracted from literature and corresponding to alumina forming alloys, when exposed to HLMs, which fit very well with our findings. Chromium and aluminium contents of 12.5-17 wt.% and 6-7.5 wt.%, respectively, are high enough to obtain thin, stable and protective alumina scales on Fe-Cr-Al-based alloys exposed to oxygen containing lead at 400, 500 and 600 °C. For the temperature range and exposure times used during the current evaluation, the growth rate of the alumina scale was low. No area with detached scale was observed and no trace of α-Al2O3 was detected.

  19. Chapter 8. Resident Group Influences on Team Functioning

    ERIC Educational Resources Information Center

    Burford, Gale E.; Fulcher, Leon C.

    2006-01-01

    Research has documented important interplays between the diagnostic characteristics of residents in group care centers and the functioning of staff teams responsible for the delivery of services. Factors that impact on the quality of working life satisfactions and frustrations are variable over time and may originate from within the team, the…

  20. Functional group accessibility in hydrogen bonded polymer blends

    NASA Astrophysics Data System (ADS)

    Pehlert, George James

    Intramolecular screening and functional group accessibility are important concepts in hydrogen bonded polymer blends. Intramolecular screening results from the fact that the units in a polymer are linked together via covalent bonds (chain connectivity). This linking together of the units results in an increase in the number of same chain contacts (self-association) due to the chains bending back upon themselves, both locally and through long range effects. Because of this effect, the number of interchain contacts (interassociation) in a polymer blend is significantly lower than that observed in an analogous low molecular weight mixture. In addition to intramolecular screening, evidence has been found showing that the accessibility of functional groups is affected by factors such as the functional groups being too close to one another along the (co)polymer chain and steric shielding due to the presence of bulky or long chain side groups. The effect of these factors on the scaling and transferability of self-association and interassociation equilibrium constants is discussed, together with ramifications in terms of the predictions of miscibility windows and maps (using the association model) for hydrogen bonded polymer blends.

  1. Experimental study of the thermal stability of materials in high temperature oxygen-containing media

    NASA Technical Reports Server (NTRS)

    Abaltusov, Y. Y.; Bagramyan, A. R.; Grishin, A. M.; Yukhvid, V. I.

    1986-01-01

    An experimental study is made of the interaction of several materials with a high temperature medium containing oxygen. The temperature of the surface was measured as a function of time. It is found that the higher the velocity of mass removal from the surface, the more effective is the material from the viewpoint of heat resistance.

  2. [Study on Characteristics of Terahertz Spectra of Organic Functional Groups].

    PubMed

    Ma, Chun-qian; Xu, Xiang-dong; Zou, Rui-jiao; Liu, Yi-ke; He, Qiong; Jiang, Ya-dong; Huang, Rui; Wen, Yue-jiang; Sun, Zi-qiang

    2015-04-01

    Fourier transform infrared (FTIR) was exploited to measure terahertz (THz) spectra in the wave number range of 30-300 cm(-1) for saturated straight chain organic molecules at room temperature. The results reveal that different organic functional groups exhibit different THz spectral characteristics. The absorption peaks of vibration modes of organic crystal lattice locate in high frequency range of THz, while those of vibration modes of intermolecular hydrogen (H) bonds appear in low frequency range of THz. Moreover, a typical absorption peak of intermolecular H bonds caused by saturated straight-chain monohydric alcohol hydroxyl functional groups locates at 57 cm(-1), while a characteristic absorption peak of intermolecular hydrogen bonds caused by triacontanoic acid carboxyl functional groups appears at 74 cm(-1). The intermolecular H bonds not only result in that the THz absorbing abilities of triacontanol and triacontanoic acid are significantly stronger than that of triacontane, but also cause regular red-shift and blue-shift of the THz absorption peaks of triacontanoic acid, as compared with those of triacontanol. In addition, density functional theory (DFT) B3LYP/6-311G(d,p) basis set was employed to simulate the THz spectra of saturated straight-chain alkane, alkanol and acid, respectively. The simulation results indicate that for the organic molecules with stronger intermolecular H bonds, lower consistent degree of the THz spectrum simulated from monomer molecule with the THz spectrum experimentally measured will occur. Moreover, the simulation results of dimer structures agree well with the measured spectra as compared to those simulated from monomer molecule structures. The results presented in this work are of great significance not only to the study of the THz spectral characteristics of other organic functional groups, but also to the clarification of the vibration modes of organic molecules. Particularly, our results are also helpful for clarifying

  3. Groups as units of functional analysis, individuals as proximate mechanisms.

    PubMed

    Wilson, David Sloan

    2014-06-01

    Whenever selection operates at a given level of a multitier hierarchy, units at that level should become the object of functional analysis, and units at lower levels should be studied as proximate mechanisms. This intuition already exists for the study of genes in individuals, when individuals are the unit of selection. It is only beginning to be applied for the study of individuals in groups, when groups are the unit of selection. Smaldino's target article is an important step in this direction with an emphasis on human cultural evolution, but the same algorithm applies to all multilevel evolutionary processes.

  4. Oxidation and microstrucure of V-Cr-Ti alloys exposed to oxygen-containing environments

    SciTech Connect

    Natesan, K.; Uz, M.; Ulie, T.

    1997-08-01

    The objectives of this task are to (a) evaluate the oxygen uptake of several V-Cr-Ti alloys as a function of temperature and oxygen partial pressure in the exposure environment, (b) examine the microstructural characteristics of oxide scales and oxygen trapped at the grain boundaries in the substrate alloys, and (c) evaluate the influence of alloy composition on oxygen uptake and develop correlation(s) between alloy composition, exposure environment, and temperature.

  5. Oxygen functional groups in graphitic carbon nitride for enhanced photocatalysis.

    PubMed

    Liu, Shizhen; Li, Degang; Sun, Hongqi; Ang, Ha Ming; Tadé, Moses O; Wang, Shaobin

    2016-04-15

    Metal-free semiconductors offer a new opportunity for environmental photocatalysis toward a potential breakthrough in high photo efficiency with complete prevention of metal leaching. In this study, graphitic carbon nitride (GCN) modified by oxygen functional groups was synthesized by a hydrothermal treatment of pristine GCN at different temperatures with H2O2. Insights into the emerging characteristics of the modified GCN in photocatalysis were obtained by determining the optical properties, band structure, electrochemical activity and pollutant degradation efficiency. It was found that the introduction of GCN with oxygen functional groups can enhance light absorption and accelerate electron transfer so as to improve the photocatalytic reaction efficiency. The photoinduced reactive radicals and the associated photodegradation were investigated by in situ electron paramagnetic resonance (EPR). The reactive radicals, O2(-) and OH, were responsible for organic degradation.

  6. Properties of graphene inks stabilized by different functional groups

    NASA Astrophysics Data System (ADS)

    Wei, Di; Li, Hongwei; Han, Dongxue; Zhang, Qixian; Niu, Li; Yang, Huafeng; Bower, Chris; Andrew, Piers; Ryhänen, Tapani

    2011-06-01

    Different graphene inks have been synthesized by chemical methods. These uniform dispersions were stabilized by various functional groups such as room temperature ionic liquid, polyaniline, polyelectrolyte (poly[2,5-bis(3-sulfonatopropoxy)-1,4-ethynylphenylene-alt-1,4-ethynylphenylene] sodium salt) and poly(styrenesulfonate) (PSS). The dispersions can be easily cast into high-quality, free-standing films but with very different physiochemical properties such as surface tension and adhesion. SEM and AFM methods have been applied to have a detailed study of the properties of the inks. It is found that graphenes modified by p-type polyaniline show the highest surface tension. Diverse surface adhesive properties to the substrate are also found with various functional groups. The different viscoelasticities of graphene inks were related to the microscopic structure of their coating layer and subsequently related to the configuration, chemistry and molecular dimensions of the modifying molecules to establish the property-structure relationship. Modifications of graphene inks made from chemical reduction cannot only enable cost-effective processing for printable electronics but also extend the applications into, for example, self-assembly of graphene via bottom-up nano-architecture and surface energy engineering of the graphenes. To fabricate useful devices, understanding the surface properties of graphene inks is very important. It is the first paper of this kind to study the surface tension and adhesion of graphene influenced by different functional groups.

  7. Functional renormalization group analysis of tensorial group field theories on Rd

    NASA Astrophysics Data System (ADS)

    Geloun, Joseph Ben; Martini, Riccardo; Oriti, Daniele

    2016-07-01

    Rank-d tensorial group field theories are quantum field theories (QFTs) defined on a group manifold G×d , which represent a nonlocal generalization of standard QFT and a candidate formalism for quantum gravity, since, when endowed with appropriate data, they can be interpreted as defining a field theoretic description of the fundamental building blocks of quantum spacetime. Their renormalization analysis is crucial both for establishing their consistency as quantum field theories and for studying the emergence of continuum spacetime and geometry from them. In this paper, we study the renormalization group flow of two simple classes of tensorial group field theories (TGFTs), defined for the group G =R for arbitrary rank, both without and with gauge invariance conditions, by means of functional renormalization group techniques. The issue of IR divergences is tackled by the definition of a proper thermodynamic limit for TGFTs. We map the phase diagram of such models, in a simple truncation, and identify both UV and IR fixed points of the RG flow. Encouragingly, for all the models we study, we find evidence for the existence of a phase transition of condensation type.

  8. Electronic spectra of oxygen containing polycyclic hydrocarbon cations and the protonated analogues

    NASA Astrophysics Data System (ADS)

    Chakraborty, Arghya; Fulara, Jan; Maier, John P.

    2015-08-01

    The electronic transitions of 9-fluorenone FL+ and 2,3,6,7-dibenzotropone DBT+ cations were detected in 6 K neon matrices following a mass-selective deposition. The absorptions at 649.2 and 472.2 nm are assigned to the 2 2 B 1 ← X ˜ 2 A 2 FL + and 2 2 A ' ← X ˜ 2 A ' DBT + transitions. Absorption spectra of protonated 9-fluorenone H+-FL and 2,3,6,7-dibenzotropone H+-DBT have also been measured. Protonation of the oxygenated polycyclic aromatic hydrocarbons is carried out in a hot cathode source via in situ produced protonated ethanol. Vibrationally resolved absorptions commencing at 423.3 nm of H-FL+ and two band systems of H-DBT+ with origins at 502.4 and 371.5 nm are assigned to the 2 1 A ' ← X ˜ 1 A ' electronic transition of 9-hydroxy-fluorenyl cation and 1 1 A ← X ˜ 1 A , 2 1 A ← X ˜ 1 A of 2,3,6,7-dibenzocycloheptenol cation. The assignments are based on vertical excitation energy calculations with time dependent density functional theory, symmetry adapted cluster configuration interaction, and MS-CASPT2 methods.

  9. Along the Ta Diffusion Path Through a Boron and Oxygen Containing Tri-layer Structure

    NASA Astrophysics Data System (ADS)

    Ying, Ji-Feng; Ji, Rong; Wang, Chen Chen; Ter Lim, Sze; Xie, Huiqing; Gerard, Ernult F.

    2014-08-01

    Diffusion and migration of elements are commonly observed in the fabrication of multilayer thin-film devices, including those of STT-RAM. The CoFeB/MgO/CoFeB tri-layer thin-film stack has been widely used in the design of STT-RAM devices as the functional magnetic-tunnel-junction (MTJ) structure. Such issues faced in the fabrication of these devices have been extensively researched from the stand point of engineering the materials property and structure to achieve the best MTJ performance. In this work, we conducted a detailed examination of the chemical-state change of the Ta and B in a CoFeB/MgO/CoFeB/Ta film stack by using x-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry. We showed that the chemical-state change of Ta and B is a result of the Ta diffusion phenomena through the CoFeB/MgO/CoFeB tri-layer structure. In particular, we report the evidences of the formation of TaB x O y compound at some considerable depth away from the Ta layer. Also of value to XPS spectroscopy, the Ta binding energy for such TaB x O y compound is reported for the first time.

  10. Electronic spectra of oxygen containing polycyclic hydrocarbon cations and the protonated analogues.

    PubMed

    Chakraborty, Arghya; Fulara, Jan; Maier, John P

    2015-08-28

    The electronic transitions of 9-fluorenone FL(+) and 2,3,6,7-dibenzotropone DBT(+) cations were detected in 6 K neon matrices following a mass-selective deposition. The absorptions at 649.2 and 472.2 nm are assigned to the 2 (2)B1←X̃(2)A2 FL(+) and 2(2)A(')←X̃(2)A(') DBT(+) transitions. Absorption spectra of protonated 9-fluorenone H(+)-FL and 2,3,6,7-dibenzotropone H(+)-DBT have also been measured. Protonation of the oxygenated polycyclic aromatic hydrocarbons is carried out in a hot cathode source via in situ produced protonated ethanol. Vibrationally resolved absorptions commencing at 423.3 nm of H-FL(+) and two band systems of H-DBT(+) with origins at 502.4 and 371.5 nm are assigned to the 2(1)A(')←X̃(1)A(') electronic transition of 9-hydroxy-fluorenyl cation and 1 (1)A←X̃(1)A, 2 (1)A←X̃(1)A of 2,3,6,7-dibenzocycloheptenol cation. The assignments are based on vertical excitation energy calculations with time dependent density functional theory, symmetry adapted cluster configuration interaction, and MS-CASPT2 methods. PMID:26328848

  11. Characterization of Sea Lettuce Surface Functional Groups by Potentiometric Titrations

    NASA Astrophysics Data System (ADS)

    Ebling, A. M.; Schijf, J.

    2008-12-01

    In pursuit of our ultimate goal to better understand the prodigious capacity of the marine macroalga Ulva lactuca (sea lettuce) for adsorbing a broad range of dissolved trace metals from seawater, we performed an initial characterization of its surface functional groups. Specifically, the number of distinct functional groups as well as their individual bulk concentrations and acid dissociation constants (pKas) were determined by potentiometric titrations in NaCl solutions of various ionic strengths (I = 0.01-5.0 M), under inert nitrogen atmosphere at 25°C. Depending on the ionic strength, Ulva samples were manually titrated down to pH 2 or 3 with 1 N HCl and then up to pH 10 with 1 N NaOH in steps of 0.1-0.2 units, continuously monitoring pH with a glass combination electrode. Titrations of a dehydrated Ulva standard reference material (BCR-279) were compared with fresh Ulva tissue cultured in our laboratory. A titration in filtered natural seawater was also compared with one in an NaCl solution of equal ionic strength. Equilibrium constants for the ionization of water in NaCl solutions as a function of ionic strength were obtained from the literature. Fits to the titration data ([H]T vs. pH) were performed with the FITEQL4.0 computer code using non-electrostatic 3-, 4-, and 5-site models, either by fixing ionic strength at its experimental value or by allowing it to be extrapolated to zero, while considering all functional group pKas and bulk concentrations as adjustable parameters. Since pKas and bulk concentrations were found to be strongly correlated, the latter were also fixed in some cases to further constrain the pKas. Whereas these calculations are currently ongoing, preliminary results point to three, possibly four, functional groups with pKas of about 4.1, 6.3, and 9.5 at I = 0. Bulk concentrations of the three groups are very similar, about 5-6×10-4 mol/g based on dry weight, which suggests that all are homogeneously distributed over the surface and

  12. Functional group diversity of bee pollinators increases crop yield

    PubMed Central

    Hoehn, Patrick; Tscharntke, Teja; Tylianakis, Jason M; Steffan-Dewenter, Ingolf

    2008-01-01

    Niche complementarity is a commonly invoked mechanism underlying the positive relationship between biodiversity and ecosystem functioning, but little empirical evidence exists for complementarity among pollinator species. This study related differences in three functional traits of pollinating bees (flower height preference, daily time of flower visitation and within-flower behaviour) to the seed set of the obligate cross-pollinated pumpkin Cucurbita moschata Duch. ex Poir. across a land-use intensity gradient from tropical rainforest and agroforests to grassland in Indonesia. Bee richness and abundance changed with habitat variables and we used this natural variation to test whether complementary resource use by the diverse pollinator community enhanced final yield. We found that pollinator diversity, but not abundance, was positively related to seed set of pumpkins. Bees showed species-specific spatial and temporal variation in flower visitation traits and within-flower behaviour, allowing for classification into functional guilds. Diversity of functional groups explained even more of the variance in seed set (r2=45%) than did species richness (r2=32%) highlighting the role of functional complementarity. Even though we do not provide experimental, but rather correlative evidence, we can link spatial and temporal complementarity in highly diverse pollinator communities to pollination success in the field, leading to enhanced crop yield without any managed honeybees. PMID:18595841

  13. Functional group diversity of bee pollinators increases crop yield.

    PubMed

    Hoehn, Patrick; Tscharntke, Teja; Tylianakis, Jason M; Steffan-Dewenter, Ingolf

    2008-10-01

    Niche complementarity is a commonly invoked mechanism underlying the positive relationship between biodiversity and ecosystem functioning, but little empirical evidence exists for complementarity among pollinator species. This study related differences in three functional traits of pollinating bees (flower height preference, daily time of flower visitation and within-flower behaviour) to the seed set of the obligate cross-pollinated pumpkin Cucurbita moschata Duch. ex Poir. across a land-use intensity gradient from tropical rainforest and agroforests to grassland in Indonesia. Bee richness and abundance changed with habitat variables and we used this natural variation to test whether complementary resource use by the diverse pollinator community enhanced final yield. We found that pollinator diversity, but not abundance, was positively related to seed set of pumpkins. Bees showed species-specific spatial and temporal variation in flower visitation traits and within-flower behaviour, allowing for classification into functional guilds. Diversity of functional groups explained even more of the variance in seed set (r2=45%) than did species richness (r2=32%) highlighting the role of functional complementarity. Even though we do not provide experimental, but rather correlative evidence, we can link spatial and temporal complementarity in highly diverse pollinator communities to pollination success in the field, leading to enhanced crop yield without any managed honeybees.

  14. Plant functional group diversity promotes soil protist diversity.

    PubMed

    Ledeganck, Pieter; Nijs, Ivan; Beyens, Louis

    2003-07-01

    We tested whether effects of plant diversity can propagate through food webs, down to heterotrophic protists not linked directly to plants. To this end we synthesised grassland ecosystems with varying numbers of plant functional groups (FGN) and assessed corresponding changes in testate amoebae communities. The number of plant species was kept constant. When FGN was increased from 1 to 3, species number and total community density of live testate amoebae were enhanced according to a linear and a saturating function, respectively. From FGN 1 to 2, the appearance of new testate amoebae species did not affect the presence of the resident species, whereas, from FGN 2 to 3 about one quarter of the resident testate amoebae species was replaced, without altering the total species number. Overall, density by species increased, while evenness of the testate amoebae community was not affected by FGN; although Trinema lineare, one of the most common species, became more abundant. The observed relationship between plant functional group diversity and testate amoebae diversity could shed new light on the biogeographical distribution patterns of protists.

  15. Plant functional group diversity promotes soil protist diversity.

    PubMed

    Ledeganck, Pieter; Nijs, Ivan; Beyens, Louis

    2003-07-01

    We tested whether effects of plant diversity can propagate through food webs, down to heterotrophic protists not linked directly to plants. To this end we synthesised grassland ecosystems with varying numbers of plant functional groups (FGN) and assessed corresponding changes in testate amoebae communities. The number of plant species was kept constant. When FGN was increased from 1 to 3, species number and total community density of live testate amoebae were enhanced according to a linear and a saturating function, respectively. From FGN 1 to 2, the appearance of new testate amoebae species did not affect the presence of the resident species, whereas, from FGN 2 to 3 about one quarter of the resident testate amoebae species was replaced, without altering the total species number. Overall, density by species increased, while evenness of the testate amoebae community was not affected by FGN; although Trinema lineare, one of the most common species, became more abundant. The observed relationship between plant functional group diversity and testate amoebae diversity could shed new light on the biogeographical distribution patterns of protists. PMID:13677451

  16. [Functional feeding groups of macroinvertebrates in Gaira river, Colombia].

    PubMed

    Rodríguez-Barrios, Javier; Ospina-Tórres, Rodulfo; Turizo-Correa, Rodrigo

    2011-12-01

    Tropical rivers are frequently described on their biodiversity but few studies have considered the ecological value of this richness in their food webs. We determined the trophic structure of aquatic macroinvertebrate communities (expressed in the richness and abundance of taxa and biomass proportions of different functional feeding groups) at the level of the river, stretch and microhabitats (functional units - UFs). We evaluated the spatial and temporal variation of these descriptors during wet and dry events, and selected three sites associated with different altitudinal belts. We reported 109 taxa, with 11167 individuals who contributed 107.11g of biomass. Density of macroinvertebrates was favored with increasing height, and biomass showed the opposite pattern (K-W = 10.1, d.f. = 1, p < 0.05), due to the addition of large crustaceans (Macrobrachium), and the taxa diversity was higher in the middle stretch of the river (H'=3.16). The Gaira stream runs through a mid-sized river basin, for this reason we found mainly bedrock (epilithon = 50.5%), gravel and sand (43.7%). The functional unit with more habitat and food resources that contains a higher abundance of leaf litter macroinvertebrates was foliage followed by epilithon, fine sediment and gravel-sand (K-W = 25.3, d.f. = 3, p < 0.05). The biomass values of these organisms were higher in leaves followed by gravel-sands, epilithon and sediment (K-W = 15.3, d.f. = 3, p < 0.05). Autochthonous biomass input by different functional feeding groups can be considered very low, but they define the functionality of the stream, being represented almost exclusively by shredders (Macrobrachium, 73%), present only in the lower reaches, followed by shredder Leptonema with 15%, located mostly in the upper reaches and predatory stoneflies of the genus Anacroneuria to 6.56%, which dominated in the middle stretch of stream. Excluding Macrobrachium from the analysis, there was dominance of Anacroneuria in the lower reaches

  17. Organized thiol functional groups in mesoporous core shell colloids

    SciTech Connect

    Marchena, Martin H.; Granada, Mara; Bordoni, Andrea V.; Joselevich, Maria; Troiani, Horacio; Williams, Federico J.; Wolosiuk, Alejandro

    2012-03-15

    The co-condensation in situ of tetraethoxysilane (TEOS) and mercaptopropyltrimethoxysilane (MPTMS) using cetyltrimethylammonium bromide (CTAB) as a template results in the synthesis of multilayered mesoporous structured SiO{sub 2} colloids with 'onion-like' chemical environments. Thiol groups were anchored to an inner selected SiO{sub 2} porous layer in a bilayered core shell particle producing different chemical regions inside the colloidal layered structure. X-Ray Photoelectron Spectroscopy (XPS) shows a preferential anchoring of the -SH groups in the double layer shell system, while porosimetry and simple chemical modifications confirm that pores are accessible. We can envision the synthesis of interesting colloidal objects with defined chemical environments with highly controlled properties. - Graphical abstract: Mesoporous core shell SiO{sub 2} colloids with organized thiol groups. Highlights: Black-Right-Pointing-Pointer Double shell mesoporous silica colloids templated with CTAB. Black-Right-Pointing-Pointer Sequential deposition of mesoporous SiO{sub 2} layers with different chemistries. Black-Right-Pointing-Pointer XPS shows the selective functionalization of mesoporous layers with thiol groups.

  18. Symmetry groups, density-matrix equations and covariant Wigner functions

    NASA Astrophysics Data System (ADS)

    Santana, A. E.; Neto, A. Matos; Vianna, J. D. M.; Khanna, F. C.

    2000-06-01

    A representation theory for Lie groups is developed taking the Hilbert space, say Hw, of the w∗-algebra standard representation as the representation space. In this context the states describing physical systems are amplitude wave functions but closely connected with the notion of the density matrix. Then, based on symmetry properties, a general physical interpretation for the dual variables of thermal theories, in particular the thermofield dynamics (TFD) formalism, is introduced. The kinematic symmetries, Galilei and Poincaré, are studied and (density) amplitude matrix equations are derived for both of these cases. In the same context of group theory, the notion of phase space in quantum theory is analysed. Thus, in the non-relativistic situation, the concept of density amplitude is introduced, and as an example, a spin-half system is algebraically studied; Wigner function representations for the amplitude density matrices are derived and the connection of TFD and the usual Wigner-function methods are analysed. For the Poincaré symmetries the relativistic density matrix equations are studied for the scalar and spinorial fields. The relativistic phase space is built following the lines of the non-relativistic case. So, for the scalar field, the kinetic theory is introduced via the Klein-Gordon density-matrix equation, and a derivation of the Jüttiner distribution is presented as an example, thus making it possible to compare with the standard approaches. The analysis of the phase space for the Dirac field is carried out in connection with the dual spinor structure induced by the Dirac-field density-matrix equation, with the physical content relying on the symmetry groups. Gauge invariance is considered and, as a basic result, it is shown that the Heinz density operator (which has been used to develope a gauge covariant kinetic theory) is a particular solution for the (Klein-Gordon and Dirac) density-matrix equation.

  19. Molecular dynamics simulations of functionalized carbon nanotubes in water: Effects of type and position of functional groups

    NASA Astrophysics Data System (ADS)

    Foroutan, Masumeh; Moshari, Mahshad

    2010-11-01

    In this work the behavior of the (8,2) single walled carbon nanotubes (CNTs) and functionalized carbon nanotubes (FCNTs) with four functional groups in water were studied using molecular dynamic (MD) simulation method. Glutamine as a long chain functional group and carboxyl as a short chain functional group have been used as functional groups in FCNTs. Four functional groups in each FCNT were localized at two positions: (i) all four functional groups were in the sidewalls of nanotube, (ii) two functional groups were at the ends and two functional groups were in the sidewalls of nanotube. The intermolecular interaction energies between CNTs or FCNTs and water molecules, the plots of radial distribution function and the diffusion coefficients of CNTs and FCNTs in water were computed for investigating the effects of type and position of functional groups on the behavior of FCNTs in water. The obtained results from three methods are consistent with each others. Results showed that the position of the functional groups in FCNTs has an important role in the interaction of hydrophilic groups of FCNTs with water molecules. Furthermore we also investigated the behavior of FCNTs with sixteen carboxyl functional groups in water. The presence of these large numbers of carboxyl functional groups on the carbon nanotubes prevents water molecules from moving towards hydrophilic carboxyl functional groups. This demonstrates the advantage of using lower number of functional groups each containing many hydrophilic groups like glutamine functional group.

  20. Identifying functional sites based on prediction of charged group behavior.

    PubMed

    Ondrechen, Mary Jo

    2004-09-01

    This protocol describes the implementation and interpretation of THEMATICS, a simple computational predictor of functional information for proteins from the three-dimensional structure. This method is based on the computation of the electrical potential function for the protein and the calculation of the predicted titration curves for each of the titratable groups in the protein. While most of the titratable residues in a protein have predicted titration behavior that fits the Henderson-Hasselbalch equation, the ionizable residues in the active site generally deviate dramatically from the typical behavior. From the calculated titration curves, one identifies those residues that deviate significantly from Henderson-Hasselbalch behavior. A cluster of two or more of such deviant titratable residues in physical proximity is a reliable predictor of active-site location.

  1. FTIR Analysis of Functional Groups in Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Shokri, S. M.; McKenzie, G.; Dransfield, T. J.

    2012-12-01

    Secondary organic aerosols (SOA) are suspensions of particulate matter composed of compounds formed from chemical reactions of organic species in the atmosphere. Atmospheric particulate matter can have impacts on climate, the environment and human health. Standardized techniques to analyze the characteristics and composition of complex secondary organic aerosols are necessary to further investigate the formation of SOA and provide a better understanding of the reaction pathways of organic species in the atmosphere. While Aerosol Mass Spectrometry (AMS) can provide detailed information about the elemental composition of a sample, it reveals little about the chemical moieties which make up the particles. This work probes aerosol particles deposited on Teflon filters using FTIR, based on the protocols of Russell, et al. (Journal of Geophysical Research - Atmospheres, 114, 2009) and the spectral fitting algorithm of Takahama, et al (submitted, 2012). To validate the necessary calibration curves for the analysis of complex samples, primary aerosols of key compounds (e.g., citric acid, ammonium sulfate, sodium benzoate) were generated, and the accumulated masses of the aerosol samples were related to their IR absorption intensity. These validated calibration curves were then used to classify and quantify functional groups in SOA samples generated in chamber studies by MIT's Kroll group. The fitting algorithm currently quantifies the following functionalities: alcohols, alkanes, alkenes, amines, aromatics, carbonyls and carboxylic acids.

  2. Functional group based Ligand binding affinity scoring function at atomic environmental level

    PubMed Central

    Varadwaj, Pritish Kumar; Lahiri, Tapobrata

    2009-01-01

    Use of knowledge based scoring function (KBSF) for virtual screening and molecular docking has become an established method for drug discovery. Lack of a precise and reliable free energy function that describes several interactions including water-mediated atomic interaction between amino-acid residues and ligand makes distance based statistical measure as the only alternative. Till now all the distance based scoring functions in KBSF arena use atom singularity concept, which neglects the environmental effect of the atom under consideration. We have developed a novel knowledge-based statistical energy function for protein-ligand complexes which takes atomic environment in to account hence functional group as a singular entity. The proposed knowledge based scoring function is fast, simple to construct, easy to use and moreover it tackle the existing problem of handling molecular orientation in active site pocket. We have designed and used Functional group based Ligand retrieval (FBLR) system which can identify and detect the orientation of functional groups in ligand. This decoy searching was used to build the above KBSF to quantify the activity and affinity of high resolution protein-ligand complexes. We have proposed the probable use of these decoys in molecular build-up as a de-novo drug designing approach. We have also discussed the possible use of the said KSBF in pharmacophore fragment detection and pseudo center based fragment alignment procedure. PMID:19255647

  3. Plant functional group composition modifies the effects of precipitation change on grassland ecosystem function.

    PubMed

    Fry, Ellen L; Manning, Pete; Allen, David G P; Hurst, Alex; Everwand, Georg; Rimmler, Martin; Power, Sally A

    2013-01-01

    Temperate grassland ecosystems face a future of precipitation change, which can alter community composition and ecosystem functions through reduced soil moisture and waterlogging. There is evidence that functionally diverse plant communities contain a wider range of water use and resource capture strategies, resulting in greater resistance of ecosystem function to precipitation change. To investigate this interaction between composition and precipitation change we performed a field experiment for three years in successional grassland in southern England. This consisted of two treatments. The first, precipitation change, simulated end of century predictions, and consisted of a summer drought phase alongside winter rainfall addition. The second, functional group identity, divided the plant community into three groups based on their functional traits- broadly described as perennials, caespitose grasses and annuals- and removed these groups in a factorial design. Ecosystem functions related to C, N and water cycling were measured regularly. Effects of functional groupidentity were apparent, with the dominant trend being that process rates were higher under control conditions where a range of perennial species were present. E.g. litter decomposition rates were significantly higher in plots containing several perennial species, the group with the highest average leaf N content. Process rates were also very strongly affected by the precipitation change treatmentwhen perennial plant species were dominant, but not where the community contained a high abundance of annual species and caespitose grasses. This contrasting response could be attributable to differing rooting patterns (shallower structures under annual plants, and deeper roots under perennials) and faster nutrient uptake in annuals compared to perennials. Our results indicate that precipitation change will have a smaller effect on key process rates in grasslandscontaining a range of perennial and annual species

  4. The Formation of Oxygen-Containing Molecules in Liquid Water Environments on the Surface of Titan (Invited)

    NASA Astrophysics Data System (ADS)

    Neish, C.

    2010-12-01

    Saturn’s moon Titan represents a unique locale for studying prebiotic chemistry. Reactions occurring in its thick nitrogen - methane atmosphere produce a wide variety of organic molecules. Observations by the Voyager spacecraft found evidence for six gas-phase hydrocarbons and three nitriles, along with an enveloping haze layer shrouding the surface of the moon (Hanel et al., 1981; Kunde et al., 1981; Maguire et al., 1981). More recently, the INMS instrument on the Cassini spacecraft has found evidence for organic molecules up to its mass limit of 100 Da at altitudes as high as 1200 km (Waite et al., 2005; Vuitton et al. 2007). Laboratory experiments that simulate the reactions occurring in Titan’s atmosphere produce many of the same organic molecules observed by Voyager and Cassini, along with organic precipitates known as tholins. Tholins have the general formula CxHyNz and are spectrally similar to Titan’s haze (Khare et al., 1984). Though interesting from the point of view of organic chemistry, the molecules found in Titan’s atmosphere stop short of addressing questions related to the origins of life. Oxygen - a key element for most known biological molecules - is generally lacking in Titan’s atmosphere. The most abundant oxygenated molecule, CO, is present at only ~50 ppm (de Kok et al., 2007). However, if Titan’s atmospheric organic molecules mix with water found in cryovolcanic lavas or impact melts, they may react to produce oxygen-containing, prebiotic species. In this paper, I will show that reactions between Titan tholins and low temperature aqueous solutions produce a wide variety of oxygen-containing species. These reactions display first-order kinetic behaviour with half-lives between 0.4 to 7 days at 273 K (in water) and between 0.3 and 14 days at 253 K (in 13 wt. % ammonia-water). Tholin hydrolysis is thus very fast compared to the freezing timescales of impact melts and volcanic sites on Titan, which take hundreds to thousands of years

  5. Highlighting functional groups in self-assembled overlayers with specific functionalized scanning tunnelling microscopy tips

    NASA Astrophysics Data System (ADS)

    Volcke, Cedric; Simonis, Priscilla; Thiry, Paul A.; Lambin, Philippe; Culot, Christine; Humbert, Christophe

    2005-11-01

    Overlayers of a fatty acid (palmitic and lauric acid) formed at the interface between a solution of this molecule in phenyloctane and the basal plane of graphite are studied by in situ scanning tunnelling microscopy. The layers organize into lamellae, which are formed by a close packing arrangement of molecules parallel to the graphite surface. Chemical modification of the STM tips used allowed identification of the functional group. Indeed, the gold tips used are functionalized with 4-mercaptobenzoic acid (4-MBA) and 4-mercaptotoluene (4-MT). The same functional group on a sample is then 'seen' as a dark and a bright spot when imaged with 4-MBA and 4-MT modified tips, respectively. This contrast distinction is related to interactions (or a lack of them) between the carboxyl group on the sample and molecules on the tip, which can facilitate (or hinder) the electron tunnelling.

  6. Sleeping functional group drives coral-reef recovery.

    PubMed

    Bellwood, David R; Hughes, Terry P; Hoey, Andrew S

    2006-12-19

    The world's coral reefs are in decline, with many exhibiting a phase shift from coral to macroalgal dominance . This change is often associated with habitat loss and overharvesting of herbivorous fishes, particularly parrotfishes and surgeonfishes . The challenge is to reverse this decline and enhance the resilience of coral-reef ecosystems . We demonstrate, by using a large-scale experimentally induced phase shift, that the rapid reversal from a macroalgal-dominated to a coral- and epilithic algal-dominated state was not a result of herbivory by parrotfishes or surgeonfishes. Surprisingly, phase-shift reversal was primarily driven by a single batfish species (Platax pinnatus), a fish previously regarded as an invertebrate feeder. The 43 herbivorous fishes in the local fauna played only a minor role, suggesting that biodiversity may not offer the protection we hoped for in complex ecosystems. Our findings highlight the dangers faced by coral reefs and other threatened complex ecosystems: Species or functional groups that prevent phase shifts may not be able to reverse phase shifts once they occur. Nevertheless, reversal is possible. The critical issue is to identify and protect those groups that underpin the resilience and regeneration of complex ecosystems.

  7. The Cockayne syndrome group B protein is a functional dimer.

    PubMed

    Christiansen, Mette; Thorslund, Tina; Jochimsen, Bjarne; Bohr, Vilhelm A; Stevnsner, Tinna

    2005-09-01

    Cockayne syndrome (CS) is a rare inherited human genetic disorder characterized by developmental abnormalities, UV sensitivity, and premature aging. The CS group B (CSB) protein belongs to the SNF2-family of DNA-dependent ATPases and is implicated in transcription elongation, transcription coupled repair, and base excision repair. It is a DNA stimulated ATPase and remodels chromatin in vitro. We demonstrate for the first time that full-length CSB positively cooperates in ATP hydrolysis as a function of protein concentration. We have investigated the quaternary structure of CSB using a combination of protein-protein complex trapping experiments and gel filtration, and found that CSB forms a dimer in solution. Chromatography studies revealed that enzymatically active CSB has an apparent molecular mass of approximately 360 kDa, consistent with dimerization of CSB. Importantly, in vivo protein cross-linking showed the presence of the CSB dimer in the nucleus of HeLa cells. We further show that dimerization occurs through the central ATPase domain of the protein. These results have implications for the mechanism of action of CSB, and suggest that other SNF2-family members might also function as dimers. PMID:16128801

  8. Observations of Adolescent Peer Group Interactions as a Function of Within- and Between-Group Centrality Status

    ERIC Educational Resources Information Center

    Ellis, Wendy E.; Dumas, Tara M.; Mahdy, Jasmine C.; Wolfe, David A.

    2012-01-01

    Observations of adolescent (n = 258; M age = 15.45) peer group triads (n = 86) were analyzed to identify conversation and interaction styles as a function of within-group and between-group centrality status. Group members' discussions about hypothetical dilemmas were coded for agreements, disagreements, commands, and opinions. Interactions during…

  9. Nucleotide substitutions revealing specific functions of Polycomb group genes.

    PubMed

    Bajusz, Izabella; Sipos, László; Pirity, Melinda K

    2015-04-01

    POLYCOMB group (PCG) proteins belong to the family of epigenetic regulators of genes playing important roles in differentiation and development. Mutants of PcG genes were isolated first in the fruit fly, Drosophila melanogaster, resulting in spectacular segmental transformations due to the ectopic expression of homeotic genes. Homologs of Drosophila PcG genes were also identified in plants and in vertebrates and subsequent experiments revealed the general role of PCG proteins in the maintenance of the repressed state of chromatin through cell divisions. The past decades of gene targeting experiments have allowed us to make significant strides towards understanding how the network of PCG proteins influences multiple aspects of cellular fate determination during development. Being involved in the transmission of specific expression profiles of different cell lineages, PCG proteins were found to control wide spectra of unrelated epigenetic processes in vertebrates, such as stem cell plasticity and renewal, genomic imprinting and inactivation of X-chromosome. PCG proteins also affect regulation of metabolic genes being important for switching programs between pluripotency and differentiation. Insight into the precise roles of PCG proteins in normal physiological processes has emerged from studies employing cell culture-based systems and genetically modified animals. Here we summarize the findings obtained from PcG mutant fruit flies and mice generated to date with a focus on PRC1 and PRC2 members altered by nucleotide substitutions resulting in specific alleles. We also include a compilation of lessons learned from these models about the in vivo functions of this complex protein family. With multiple knockout lines, sophisticated approaches to study the consequences of peculiar missense point mutations, and insights from complementary gain-of-function systems in hand, we are now in a unique position to significantly advance our understanding of the molecular basis of

  10. Effects of oxygen-containing terpenes as skin permeation enhancers on the lipoidal pathways of human epidermal membrane.

    PubMed

    Chantasart, Doungdaw; Pongjanyakul, Thaned; Higuchi, William I; Li, S Kevin

    2009-10-01

    The present study investigated the effects of oxygen-containing terpenes as skin permeation enhancers on the lipoidal pathways of human epidermal membrane (HEM). The enhancement (E(HEM)) effects of menthol, thymol, carvacrol, menthone, and cineole on the transport of a probe permeant, corticosterone, across HEM were determined. It was found that the enhancer potencies of menthol, thymol, carvacrol, and menthone were essentially the same and higher than that of cineole based on their aqueous concentration in the diffusion cell chamber at E(HEM) = 4. Thymol and carvacrol also had the same E(HEM) = 10 concentration further supporting that they had the same enhancer potency based on the aqueous concentration. The uptake amounts of terpene into the HEM stratum corneum (SC) intercellular lipid under the same conditions indicate that the intrinsic potencies of the studied terpenes are the same based on their concentration in the SC and similar to those of n-alkanol and n-alkylphenyl alcohol. Moreover, they are all better enhancers compared to branched-chain alkanol. The approximately same uptake enhancement of beta-estradiol induced by the studied terpenes and alcohols at E(HEM) conditions into the SC intercellular lipids suggests that the mechanism of enhancement action for the terpenes and those of alcohols are essentially the same. PMID:19156845

  11. Functional movement screen scores in a group of running athletes.

    PubMed

    Loudon, Janice K; Parkerson-Mitchell, Amy J; Hildebrand, Laurie D; Teague, Connie

    2014-04-01

    The purpose of this study was to determine the mean values of the functional movement screen (FMS) in a group of long-distance runners. The secondary aims were to investigate whether the FMS performance differed between sexes and between young and older runners. Forty-three runners, 16 women (mean age = 33.5 years, height = 165.2 cm, weight = 56.3 kg, and body mass index [BMI] = 20.6) and 27 men (mean age = 39.3 years, height = 177.6 cm, weight = 75.8 kg, and BMI = 24.2) performed the FMS. All the runners were injury-free and ran >30 km·wk. Independent t-tests were performed on the composite scores to examine the differences between men and women and also between young (<40 years) and older runners (>40 years). Contingency tables (2 × 2) were developed for each of the 7 screening tests to further look at the differences in groups for each single test. The χ values were calculated to determine significant differences. Statistical significance was set at p ≤ 0.05. There was no significant difference in the composite score between women and men. There were significant differences between the sexes in the push-up and straight leg test scores, with the women scoring better on each test. A significant difference was found in the composite scores between younger and older runners (p < 0.000). Additional score differences were found for the squat, hurdle step, and in-line lunge tests with the younger runners scoring better. This study provided mean values for the FMS in a cohort of long-distance runners. These values can be used as a reference for comparing FMST scores in other runners who are screened with this tool.

  12. Highly adaptive tests for group differences in brain functional connectivity.

    PubMed

    Kim, Junghi; Pan, Wei

    2015-01-01

    Resting-state functional magnetic resonance imaging (rs-fMRI) and other technologies have been offering evidence and insights showing that altered brain functional networks are associated with neurological illnesses such as Alzheimer's disease. Exploring brain networks of clinical populations compared to those of controls would be a key inquiry to reveal underlying neurological processes related to such illnesses. For such a purpose, group-level inference is a necessary first step in order to establish whether there are any genuinely disrupted brain subnetworks. Such an analysis is also challenging due to the high dimensionality of the parameters in a network model and high noise levels in neuroimaging data. We are still in the early stage of method development as highlighted by Varoquaux and Craddock (2013) that "there is currently no unique solution, but a spectrum of related methods and analytical strategies" to learn and compare brain connectivity. In practice the important issue of how to choose several critical parameters in estimating a network, such as what association measure to use and what is the sparsity of the estimated network, has not been carefully addressed, largely because the answers are unknown yet. For example, even though the choice of tuning parameters in model estimation has been extensively discussed in the literature, as to be shown here, an optimal choice of a parameter for network estimation may not be optimal in the current context of hypothesis testing. Arbitrarily choosing or mis-specifying such parameters may lead to extremely low-powered tests. Here we develop highly adaptive tests to detect group differences in brain connectivity while accounting for unknown optimal choices of some tuning parameters. The proposed tests combine statistical evidence against a null hypothesis from multiple sources across a range of plausible tuning parameter values reflecting uncertainty with the unknown truth. These highly adaptive tests are not only

  13. Highly adaptive tests for group differences in brain functional connectivity.

    PubMed

    Kim, Junghi; Pan, Wei

    2015-01-01

    Resting-state functional magnetic resonance imaging (rs-fMRI) and other technologies have been offering evidence and insights showing that altered brain functional networks are associated with neurological illnesses such as Alzheimer's disease. Exploring brain networks of clinical populations compared to those of controls would be a key inquiry to reveal underlying neurological processes related to such illnesses. For such a purpose, group-level inference is a necessary first step in order to establish whether there are any genuinely disrupted brain subnetworks. Such an analysis is also challenging due to the high dimensionality of the parameters in a network model and high noise levels in neuroimaging data. We are still in the early stage of method development as highlighted by Varoquaux and Craddock (2013) that "there is currently no unique solution, but a spectrum of related methods and analytical strategies" to learn and compare brain connectivity. In practice the important issue of how to choose several critical parameters in estimating a network, such as what association measure to use and what is the sparsity of the estimated network, has not been carefully addressed, largely because the answers are unknown yet. For example, even though the choice of tuning parameters in model estimation has been extensively discussed in the literature, as to be shown here, an optimal choice of a parameter for network estimation may not be optimal in the current context of hypothesis testing. Arbitrarily choosing or mis-specifying such parameters may lead to extremely low-powered tests. Here we develop highly adaptive tests to detect group differences in brain connectivity while accounting for unknown optimal choices of some tuning parameters. The proposed tests combine statistical evidence against a null hypothesis from multiple sources across a range of plausible tuning parameter values reflecting uncertainty with the unknown truth. These highly adaptive tests are not only

  14. A conceptual basis to encode and detect organic functional groups in XML.

    PubMed

    Sankar, Punnaivanam; Krief, Alain; Vijayasarathi, Durairaj

    2013-06-01

    A conceptual basis to define and detect organic functional groups is developed. The basic model of a functional group is termed as a primary functional group and is characterized by a group center composed of one or more group center atoms bonded to terminal atoms and skeletal carbon atoms. The generic group center patterns are identified from the structures of known functional groups. Accordingly, a chemical ontology 'Font' is developed to organize the existing functional groups as well as the new ones to be defined by the chemists. The basic model is extended to accommodate various combinations of primary functional groups as functional group assemblies. A concept of skeletal group is proposed to define the characteristic groups composed of only carbon atoms to be regarded as equivalent to functional groups. The combination of primary functional groups with skeletal groups is categorized as skeletal group assembly. In order to make the model suitable for reaction modeling purpose, a Graphical User Interface (GUI) is developed to define the functional groups and to encode in XML format appropriate to detect them in chemical structures. The system is capable of detecting multiple instances of primary functional groups as well as the overlapping poly-functional groups as the respective assemblies. PMID:23666030

  15. The Mechanism and Function of Group II Chaperonins.

    PubMed

    Lopez, Tom; Dalton, Kevin; Frydman, Judith

    2015-09-11

    Protein folding in the cell requires the assistance of enzymes collectively called chaperones. Among these, the chaperonins are 1-MDa ring-shaped oligomeric complexes that bind unfolded polypeptides and promote their folding within an isolated chamber in an ATP-dependent manner. Group II chaperonins, found in archaea and eukaryotes, contain a built-in lid that opens and closes over the central chamber. In eukaryotes, the chaperonin TRiC/CCT is hetero-oligomeric, consisting of two stacked rings of eight paralogous subunits each. TRiC facilitates folding of approximately 10% of the eukaryotic proteome, including many cytoskeletal components and cell cycle regulators. Folding of many cellular substrates of TRiC cannot be assisted by any other chaperone. A complete structural and mechanistic understanding of this highly conserved and essential chaperonin remains elusive. However, recent work is beginning to shed light on key aspects of chaperonin function and how their unique properties underlie their contribution to maintaining cellular proteostasis. PMID:25936650

  16. Functional trait responses to grazing are mediated by soil moisture and plant functional group identity.

    PubMed

    Zheng, Shuxia; Li, Wenhuai; Lan, Zhichun; Ren, Haiyan; Wang, Kaibo

    2015-12-11

    Abundant evidence has shown that grazing alters plant functional traits, community structure and ecosystem functioning of grasslands. Few studies, however, have tested how plant responses to grazing are mediated by resource availability and plant functional group identity. We examined the effects of grazing on functional traits across a broad range of species along a soil moisture gradient in Inner Mongolia grassland. Our results showed that trait syndromes of plant size (individual biomass) and shoot growth (leaf N content and leaf density) distinguished plant species responses to grazing. The effects of grazing on functional traits were mediated by soil moisture and dependent on functional group identity. For most species, grazing decreased plant height but increased leaf N and specific leaf area (SLA) along the moisture gradient. Grazing enhanced the community-weighted attributes (leaf NCWM and SLACWM), which were triggered mainly by the positive trait responses of annuals and biennials and perennial grasses, and increased relative abundance of perennial forbs. Our results suggest that grazing-induced species turnover and increased intraspecific trait variability are two drivers for the observed changes in community weighted attributes. The dominant perennial bunchgrasses exhibited mixed tolerance-resistance strategies to grazing and mixed acquisitive-conservative strategies in resource utilization.

  17. Functional trait responses to grazing are mediated by soil moisture and plant functional group identity.

    PubMed

    Zheng, Shuxia; Li, Wenhuai; Lan, Zhichun; Ren, Haiyan; Wang, Kaibo

    2015-01-01

    Abundant evidence has shown that grazing alters plant functional traits, community structure and ecosystem functioning of grasslands. Few studies, however, have tested how plant responses to grazing are mediated by resource availability and plant functional group identity. We examined the effects of grazing on functional traits across a broad range of species along a soil moisture gradient in Inner Mongolia grassland. Our results showed that trait syndromes of plant size (individual biomass) and shoot growth (leaf N content and leaf density) distinguished plant species responses to grazing. The effects of grazing on functional traits were mediated by soil moisture and dependent on functional group identity. For most species, grazing decreased plant height but increased leaf N and specific leaf area (SLA) along the moisture gradient. Grazing enhanced the community-weighted attributes (leaf NCWM and SLACWM), which were triggered mainly by the positive trait responses of annuals and biennials and perennial grasses, and increased relative abundance of perennial forbs. Our results suggest that grazing-induced species turnover and increased intraspecific trait variability are two drivers for the observed changes in community weighted attributes. The dominant perennial bunchgrasses exhibited mixed tolerance-resistance strategies to grazing and mixed acquisitive-conservative strategies in resource utilization. PMID:26655858

  18. Functional trait responses to grazing are mediated by soil moisture and plant functional group identity

    PubMed Central

    Zheng, Shuxia; Li, Wenhuai; Lan, Zhichun; Ren, Haiyan; Wang, Kaibo

    2015-01-01

    Abundant evidence has shown that grazing alters plant functional traits, community structure and ecosystem functioning of grasslands. Few studies, however, have tested how plant responses to grazing are mediated by resource availability and plant functional group identity. We examined the effects of grazing on functional traits across a broad range of species along a soil moisture gradient in Inner Mongolia grassland. Our results showed that trait syndromes of plant size (individual biomass) and shoot growth (leaf N content and leaf density) distinguished plant species responses to grazing. The effects of grazing on functional traits were mediated by soil moisture and dependent on functional group identity. For most species, grazing decreased plant height but increased leaf N and specific leaf area (SLA) along the moisture gradient. Grazing enhanced the community-weighted attributes (leaf NCWM and SLACWM), which were triggered mainly by the positive trait responses of annuals and biennials and perennial grasses, and increased relative abundance of perennial forbs. Our results suggest that grazing-induced species turnover and increased intraspecific trait variability are two drivers for the observed changes in community weighted attributes. The dominant perennial bunchgrasses exhibited mixed tolerance–resistance strategies to grazing and mixed acquisitive–conservative strategies in resource utilization. PMID:26655858

  19. Parent, Alkylated, and Sulfur/Oxygen-Containing Polycyclic Aromatic Hydrocarbons in Mainstream Smoke from 13 Brands of Chinese Cigarettes.

    PubMed

    Gao, Bo; Du, Xueqing; Wang, Xinming; Tang, Jianhui; Ding, Xiang; Zhang, Yanli; Bi, Xinhui; Zhang, Gan

    2015-08-01

    China has the world's largest population of smokers with serious health consequences, yet we know a very limited spectrum of hazardous chemicals in cigarette smoke even for carcinogenic polycyclic aromatic hydrocarbons (PAHs). Here, we chose 13 popular cigarette brands sold in China markets, collected particulate matters in mainstream smoke using filter pads and an automatic smoking machine, and analyzed 56 PAHs, including 31 parent, 18 alkylated, and 7 sulfur/oxygen-containing PAHs (S/O PAHs). The 56 PAHs in mainstream smoke totaled from 244.2 ± 28.5 to 10254.8 ± 481.5 ng cig(-1); parent, alkylated, and S/O PAHs shared 16-23%, 64-74%, and 6-18%, respectively. Benzo[a]pyrene (BaP) ranged 1.1-41.6 ng cig(-1), while BaP equivalent concentrations (BaPeq) ranged 3.6-120.2 ng cig(-1), but contributions to BaPeq by individual carcinogenic PAH species varied with cigarette brands. When these cigarette smoke source profiles were pooled together with those of other combustion ones available in the literature, we found that widely used diagnostic ratios of parent PAHs failed to distinguish cigarette smoke from other combustion sources, except that the ratio indeno[1,2,3-cd]pyrene/(indeno[1,2,3-cd]pyrene + benzo[g,h,i]perylene) can largely separate cigarette smoke from vehicular emissions and that the ratio of Retene/(Retene + chrysene) can further discriminate cigarette smoke from coal combustion when alkylated PAHs are involved.

  20. Plant Species and Functional Group Combinations Affect Green Roof Ecosystem Functions

    PubMed Central

    Lundholm, Jeremy; MacIvor, J. Scott; MacDougall, Zachary; Ranalli, Melissa

    2010-01-01

    Background Green roofs perform ecosystem services such as summer roof temperature reduction and stormwater capture that directly contribute to lower building energy use and potential economic savings. These services are in turn related to ecosystem functions performed by the vegetation layer such as radiation reflection and transpiration, but little work has examined the role of plant species composition and diversity in improving these functions. Methodology/Principal Findings We used a replicated modular extensive (shallow growing- medium) green roof system planted with monocultures or mixtures containing one, three or five life-forms, to quantify two ecosystem services: summer roof cooling and water capture. We also measured the related ecosystem properties/processes of albedo, evapotranspiration, and the mean and temporal variability of aboveground biomass over four months. Mixtures containing three or five life-form groups, simultaneously optimized several green roof ecosystem functions, outperforming monocultures and single life-form groups, but there was much variation in performance depending on which life-forms were present in the three life-form mixtures. Some mixtures outperformed the best monocultures for water capture, evapotranspiration, and an index combining both water capture and temperature reductions. Combinations of tall forbs, grasses and succulents simultaneously optimized a range of ecosystem performance measures, thus the main benefit of including all three groups was not to maximize any single process but to perform a variety of functions well. Conclusions/Significance Ecosystem services from green roofs can be improved by planting certain life-form groups in combination, directly contributing to climate change mitigation and adaptation strategies. The strong performance by certain mixtures of life-forms, especially tall forbs, grasses and succulents, warrants further investigation into niche complementarity or facilitation as mechanisms

  1. Polymer containing functional end groups is base for new polymers

    NASA Technical Reports Server (NTRS)

    Hirshfield, S. M.

    1971-01-01

    Butadiene is polymerized with lithium-p-lithiophenoxide to produce linear polymer containing oxy-lithium group at one end and active carbon-lithium group at other end. Living polymers represent new approach to preparation of difunctional polymers in which structural features, molecular weight, type and number of end groups are controlled.

  2. Application of macrobenthos functional groups to estimate the ecosystem health in a semi-enclosed bay.

    PubMed

    Peng, Shitao; Zhou, Ran; Qin, Xuebo; Shi, Honghua; Ding, Dewen

    2013-09-15

    In this study, the functional group concept was first applied to evaluate the ecosystem health of Bohai Bay. Macrobenthos functional groups were defined according to feeding types and divided into five groups: a carnivorous group (CA), omnivorous group (OM), planktivorous group (PL), herbivorous group (HE), and detritivorous group (DE). Groups CA, DE, OM, and PL were identified, but the HE group was absent from Bohai Bay. Group DE was dominant during the study periods. The ecosystem health was assessed using a functional group evenness index. The functional group evenness values of most sampling stations were less than 0.40, indicating that the ecosystem health was deteriorated in Bohai Bay. Such deterioration could be attributed to land reclamation, industrial and sewage effluents, oil pollution, and hypersaline water discharge. This study demonstrates that the functional group concept can be applied to ecosystem health assessment in a semi-enclosed bay.

  3. Impact of Functional Group Modifications on Designer Phenethylamine Induced Hyperthermia.

    PubMed

    Grecco, Gregory G; Sprague, Jon E

    2016-05-16

    The popularity of designer phenethylamines such as synthetic cathinones ("bath salts") has led to increased reports of life-threatening hyperthermia. The diversity of chemical modifications has resulted in the toxicological profile of most synthetic cathinones being mostly uncharacterized. Here, we investigated the thermogenic effects of six recently identified designer phenethylamines (4-methylmethamphetamine, methylone, mephedrone, butylone, pentylone, and MDPV) and compared these effects to the established thermogenic agent 3,4-methylenedioxymethamphetamine (MDMA). Specifically, we determined the impact of a β-ketone, α-alkyl, or pyrrolidine functional group on core-body temperature changes. Sprague-Dawley rats (n = 5-6) were administered a dose (30 mg/kg, sc) of a designer phenethylamine or MDMA, and core body temperature measurements were recorded at 30 min intervals for 150 min post treatment. MDMA elicited the greatest maximum temperature change (ΔTmax), and this effect was significantly greater than that of its β-ketone analogue, methylone. Temperature-area under the curves (TAUCs) and ΔTmax were also significantly different between 4-methylmethamphetamine (4-MMA) and its β-ketone analogue mephedrone. Lengthening the α-alkyl chain of methylone to produce butylone and pentylone significantly attenuated the thermogenic response on both TAUCs and ΔTmax compared to those of methylone; however, butylone and pentylone were not different from each other. Pyrrolidine substitution on the N-terminus of pentylone produces 3,4-methylenedioxypyrovalerone (MDPV), which did not significantly alter core body temperature. Thermogenic comparisons of MDMA vs methylone and 4-MMA vs mephedrone indicate that oxidation at the benzylic position significantly attenuates the hyperthermic response. Furthermore, either extending the α-alkyl chain to ethyl and propyl (butylone and pentylone, respectively) or extending the α-alkyl chain and adding a pyrrolidine on the N

  4. Students' Perceptions of Classroom Group Work as a Function of Group Member Selection

    ERIC Educational Resources Information Center

    Myers, Scott A.

    2012-01-01

    The purpose of this assessment was to examine whether differences exist between students who self-select their classroom work group members and students who are randomly assigned to their classroom work groups in terms of their use of organizational citizenship behaviors with their work group members; their commitment to, trust in, and relational…

  5. Prediction of functional sites in proteins using conserved functional group analysis.

    PubMed

    Innis, C Axel; Anand, A Prem; Sowdhamini, R

    2004-04-01

    A detailed knowledge of a protein's functional site is an absolute prerequisite for understanding its mode of action at the molecular level. However, the rapid pace at which sequence and structural information is being accumulated for proteins greatly exceeds our ability to determine their biochemical roles experimentally. As a result, computational methods are required which allow for the efficient processing of the evolutionary information contained in this wealth of data, in particular that related to the nature and location of functionally important sites and residues. The method presented here, referred to as conserved functional group (CFG) analysis, relies on a simplified representation of the chemical groups found in amino acid side-chains to identify functional sites from a single protein structure and a number of its sequence homologues. We show that CFG analysis can fully or partially predict the location of functional sites in approximately 96% of the 470 cases tested and that, unlike other methods available, it is able to tolerate wide variations in sequence identity. In addition, we discuss its potential in a structural genomics context, where automation, scalability and efficiency are critical, and an increasing number of protein structures are determined with no prior knowledge of function. This is exemplified by our analysis of the hypothetical protein Ydde_Ecoli, whose structure was recently solved by members of the North East Structural Genomics consortium. Although the proposed active site for this protein needs to be validated experimentally, this example illustrates the scope of CFG analysis as a general tool for the identification of residues likely to play an important role in a protein's biochemical function. Thus, our method offers a convenient solution to rapidly and automatically process the vast amounts of data that are beginning to emerge from structural genomics projects. PMID:15033369

  6. Dominant Functional Group Effects on the Invasion Resistance at Different Resource Levels

    PubMed Central

    Wang, Jiang; Ge, Yuan; Zhang, Chong B.; Bai, Yi; Du, Zhao K.

    2013-01-01

    Background Functional group composition may affect invasion in two ways the effect of abundance, i.e. dominance of functional group; and the effect of traits, i.e. identity of functional groups. However, few studies have focused on the role of abundance of functional group on invasion resistance. Moreover, how resource availability influences the role of the dominant functional group in invasion resistance is even less understood. Methodology/Principal Findings In this experiment, we established experimental pots using four different functional groups (annual grass, perennial grass, deciduous shrub or arbor and evergreen shrub or arbor), and the dominant functional group was manipulated. These experimental pots were respectively constructed at different soil nitrogen levels (control and fertilized). After one year of growth, we added seeds of 20 different species (five species per functional group) to the experimental pots. Fertilization significantly increased the overall invasion success, while dominant functional group had little effect on overall invasion success. When invaders were grouped into functional groups, invaders generally had lower success in pots dominated by the same functional group in the control pots. However, individual invaders of the same functional group exhibited different invasion patterns. Fertilization generally increased success of invaders in pots dominated by the same than by another functional group. However, fertilization led to great differences for individual invaders. Conclusions/Significance The results showed that the dominant functional group, independent of functional group identity, had a significant effect on the composition of invaders. We suggest that the limiting similarity hypothesis may be applicable at the functional group level, and limiting similarity may have a limited role for individual invaders as shown by the inconsistent effects of dominant functional group and fertilization. PMID:24167565

  7. Perceptual Visual Grouping under Inattention: Electrophysiological Functional Imaging

    ERIC Educational Resources Information Center

    Razpurker-Apfeld, Irene; Pratt, Hillel

    2008-01-01

    Two types of perceptual visual grouping, differing in complexity of shape formation, were examined under inattention. Fourteen participants performed a similarity judgment task concerning two successive briefly presented central targets surrounded by task-irrelevant simple and complex grouping patterns. Event-related potentials (ERPs) were…

  8. Hydrolysis of organonitrate functional groups in aerosol particles

    SciTech Connect

    Liu, Shang; Shilling, John E.; Song, Chen; Hiranuma, Naruki; Zaveri, Rahul A.; Russell, Lynn M.

    2012-10-19

    Organonitrate (ON) groups are important substituents in secondary organic aerosols. Model simulations and laboratory studies indicate a large fraction of ON groups in aerosol particles, but much lower quantities are observed in the atmosphere. Hydrolysis of ON groups in aerosol particles has been proposed recently. To test this hypothesis, we simulated formation of ON molecules in a reaction chamber under a wide range of relative humidity (0% to 90%). The mass fraction of ON groups (5% to 20% for high-NOx experiments) consistently decreased with increasing relative humidity, which was best explained by hydrolysis of ON groups at a rate of 4 day-1 (lifetime of 6 hours) for reactions under relative humidity greater than 20%. In addition, we found that secondary nitrogen-containing molecules absorb light, with greater absorption under dry and high-NOx conditions. This work provides the first evidence for particle-phase hydrolysis of ON groups, a process that could substantially reduce ON group concentration in the atmosphere.

  9. Use of morphological characteristics to define functional groups of predatory fishes in the Celtic Sea.

    PubMed

    Reecht, Y; Rochet, M-J; Trenkel, V M; Jennings, S; Pinnegar, J K

    2013-08-01

    An ecomorphological method was developed, with a focus on predation functions, to define functional groups in the Celtic Sea fish community. Eleven functional traits, measured for 930 individuals from 33 species, led to 11 functional groups. Membership of functional groups was linked to body size and taxonomy. For seven species, there were ontogenetic changes in group membership. When diet composition, expressed as the proportions of different prey types recorded in stomachs, was compared among functional groups, morphology-based predictions accounted for 28-56% of the interindividual variance in prey type. This was larger than the 12-24% of variance that could be explained solely on the basis of body size.

  10. Effects of spatial grouping on the functional response of predators

    USGS Publications Warehouse

    Cosner, C.; DeAngelis, D.L.; Ault, J.S.; Olson, D.B.

    1999-01-01

    A unified mechanistic approach is given for the derivation of various forms of functional response in predator-prey models. The derivation is based on the principle-of-mass action but with the crucial refinement that the nature of the spatial distribution of predators and/or opportunities for predation are taken into account in an implicit way. If the predators are assumed to have a homogeneous spatial distribution, then the derived functional response is prey-dependent. If the predators are assumed to form a dense colony or school in a single (possibly moving) location, or if the region where predators can encounter prey is assumed to be of limited size, then the functional response depends on both predator and prey densities in a manner that reflects feeding interference between predators. Depending on the specific assumptions, the resulting functional response may be of Beddington-DeAngelis type, of Hassell-Varley type, or ratio-dependent.

  11. Application of the functionally generated path technique to restore mandibular molars in bilateral group function occlusion.

    PubMed

    DuVall, Nicholas B; Rogers, Paul M

    2013-04-01

    The functionally generated path (FGP) is a static representation of the opposing cusps' dynamic eccentric movements from a centric position to achieve optimal articulation and occlusal harmony. When understood and appreciated, use of the FGP technique is a straightforward and practical method to achieve harmonious occlusal anatomy of restorations with the anterior determinant/anterior guidance, the posterior determinant/condylar guidance, existing occlusal and cuspal anatomy, and the neuromuscular system. Although the FGP technique is normally used in the fabrication of maxillary posterior indirect restorations, it is described and applied here in the fabrication of mandibular posterior restorations that maintained the patient's bilateral group function occlusion while eliminating the nonworking side and protrusive interferences. This novel procedure involved the use of a stone crib to intraorally construct a stone core that captured the FGP recording while simultaneously indexing to the contralateral and ipsilateral mandibular dentition. This technique lends additional stability to the stone core to minimize error during the mounting process.

  12. Functional-group specific aptamers indirectly recognizing compounds with alkyl amino group.

    PubMed

    Mei, Hongcheng; Bing, Tao; Yang, Xiaojuan; Qi, Cui; Chang, Tianjun; Liu, Xiangjun; Cao, Zehui; Shangguan, Dihua

    2012-09-01

    Aptamers are usually generated against a specific molecule. Their high selectivity makes them only suitable for studying specific targets. Since it is nearly impossible to generate aptamers for every molecule, it can be of great interest to select aptamers recognizing a common feature of a group of molecules in many applications. In this paper, we describe the selection of aptamers for indirect recognition of alkyl amino groups. Because amino groups are small and positive charged, we introduced a protection group, p-nitrobenzene sulfonyl (p-nosyl) to convert them into a form suitable for aptamer selection. Taking N(ε)-p-nosyl-L-lysine (PSL) as a target, we obtained a group of aptamers using the SELEX technique. Two optimized aptamers, M6b-M14 and M13a exhibit strong affinity to PSL with the K(d) values in the range of 2-5 μM. They also show strong affinity to other compounds containing p-nosyl-protected amino groups except those also possessing an α-carboxyl group. Both aptamers adopt an antiparallel G-quadruplex structure when binding to targets. An aptamer beacon based on M6b-M14 showed good selectivity toward the reaction mixture of p-nosyl-Cl and alkyl amino compounds, and could recognize lysine from amino acid mixtures indirectly, suggesting that aptamers against a common moiety of a certain type of molecules can potentially lead to many new applications. Through this study, we have demonstrated the ability to select aptamers for a specific part of an organic compound, and the chemical conversion approach may prove to be valuable for aptamer selection against molecules that are generally difficult for SELEX.

  13. Rectifying and negative differential resistance behaviors of a functionalized Tour wire: The position effects of functional groups

    NASA Astrophysics Data System (ADS)

    Kwong, Gordon; Zhang, Zhenhua; Pan, Jinbo

    2011-09-01

    Based on Tour wire, we construct four D-π-A molecular devices with different positional functional groups, in an attempt to explore the position effects of functional groups on their electronic transport properties and to show that some interesting physical phenomena can emerge by only varying the position of functional groups. The first-principles calculations demonstrate that the position of functional groups can affect the rectifying behaviors (rectification direction and ratio) significantly and determines whether or not the negative differential resistance (NDR) can be observed as well as the physical origin of the NDR phenomenon.

  14. [Duffy blood group antigens: structure, serological properties and function].

    PubMed

    Łukasik, Ewa; Waśniowska, Kazimiera

    2016-01-01

    Duffy (Fy) blood group antigens are located on seven-transmembrane glycoprotein expressed on erythrocytes and endothelial cells, which acts as atypical chemokine receptor (ACKR1) and malarial receptor. The biological role of the Duffy glycoprotein has not been explained yet. It is suggested that Duffy protein modulate the intensity of the inflammatory response. The Duffy blood group system consists of two major antigens, Fy(a) and Fy(b), encoded by two codominant alleles designated FY*A and FY*B which differ by a single nucleotide polymorphism (SNP) at position 125G>A of the FY gene that results in Gly42Asp amino acid change in the Fy(a) and Fy(b) antigens, respectively. The presence of antigen Fy(a) and/or Fy(b) on the erythrocytes determine three Duffy-positive phenotypes: Fy(a+b-), Fy(a-b+) and Fy(a+b+), identified in Caucasian population. The Duffy-negative phenotype Fy(a-b-), frequent in Africans, but very rare in Caucasians, is defined by the homozygous state of FY*B-33 alleles. The FY*B-33 allele is associated with a SNP -33T>C in the promoter region of the FY gene, which suppresses erythroid expression of this gene without affecting its expression in other tissues. The FY*X allele, found in Caucasians, is correlated with weak expression of Fy(b) antigen. Fy(x) antigen differs from the native Fy(b) by the Arg89Cys and Ala100Thr amino acid substitutions due to SNPs: 265C>T and 298G>A in FY*B allele. The frequency of the FY alleles shows marked geographic disparities, the FY*B-33 allele is predominant in Africans, the FY*B in Caucasians, while the FY*A allele is dominant in Asians and it is the most prevalent allele globally. PMID:26943312

  15. A Generalized Logistic Regression Procedure to Detect Differential Item Functioning among Multiple Groups

    ERIC Educational Resources Information Center

    Magis, David; Raiche, Gilles; Beland, Sebastien; Gerard, Paul

    2011-01-01

    We present an extension of the logistic regression procedure to identify dichotomous differential item functioning (DIF) in the presence of more than two groups of respondents. Starting from the usual framework of a single focal group, we propose a general approach to estimate the item response functions in each group and to test for the presence…

  16. Functional groups grafted nonwoven fabrics for blood filtration-The effects of functional groups and wettability on the adhesion of leukocyte and platelet

    NASA Astrophysics Data System (ADS)

    Yang, Chao; Cao, Ye; Sun, Kang; Liu, Jiaxin; Wang, Hong

    2011-01-01

    In this work, the effects of grafted functional groups and surface wettability on the adhesion of leukocyte and platelet were investigated by the method of blood filtration. The filter materials, poly(butylene terephthalate) nonwoven fabrics bearing different functional groups including hydroxyl (OH), carboxyl (COOH), sulfonic acid group (SO3H) and zwitterionic sulfobetaine group (⊕N((CH3)2)(CH2)3SO3⊖) with controllable wettability were prepared by UV radiation grafting vinyl monomers with these functional groups. Our results emphasized that both surface functional groups and surface wettability had significant effects on the adhesion of leukocyte and platelet. In the case of filter materials with the same wettability, leukocytes adhering to filter materials decreased in the order: the surface bearing OH only > the surface bearing both OH and COOH > the surface bearing sulfobetaine group > the surface bearing SO3H, while platelets adhering to filter materials decreased as the following order: the surface bearing SO3H > the surface bearing both OH and COOH > the surface bearing OH only > the surface bearing sulfobetaine group. As the wettability of filter materials increased, both leukocyte and platelet adhesion to filter materials declined, except that leukocyte adhesion to the surface bearing OH only remained unchanged.

  17. METALLICITY DISTRIBUTION FUNCTIONS OF FOUR LOCAL GROUP DWARF GALAXIES

    SciTech Connect

    Ross, Teresa L.; Holtzman, Jon; Saha, Abhijit; Anthony-Twarog, Barbara J. E-mail: holtz@nmsu.edu

    2015-06-15

    We present stellar metallicities in Leo I, Leo II, IC 1613, and Phoenix dwarf galaxies derived from medium (F390M) and broad (F555W, F814W) band photometry using the Wide Field Camera 3 instrument on board the Hubble Space Telescope. We measured metallicity distribution functions (MDFs) in two ways, (1) matching stars to isochrones in color–color diagrams and (2) solving for the best linear combination of synthetic populations to match the observed color–color diagram. The synthetic technique reduces the effect of photometric scatter and produces MDFs 30%–50% narrower than the MDFs produced from individually matched stars. We fit the synthetic and individual MDFs to analytical chemical evolution models (CEMs) to quantify the enrichment and the effect of gas flows within the galaxies. Additionally, we measure stellar metallicity gradients in Leo I and II. For IC 1613 and Phoenix our data do not have the radial extent to confirm a metallicity gradient for either galaxy. We find the MDF of Leo I (dwarf spheroidal) to be very peaked with a steep metal-rich cutoff and an extended metal-poor tail, while Leo II (dwarf spheroidal), Phoenix (dwarf transition), and IC 1613 (dwarf irregular) have wider, less peaked MDFs than Leo I. A simple CEM is not the best fit for any of our galaxies; therefore we also fit the “Best Accretion Model” of Lynden-Bell. For Leo II, IC 1613, and Phoenix we find similar accretion parameters for the CEM even though they all have different effective yields, masses, star formation histories, and morphologies. We suggest that the dynamical history of a galaxy is reflected in the MDF, where broad MDFs are seen in galaxies that have chemically evolved in relative isolation and narrowly peaked MDFs are seen in galaxies that have experienced more complicated dynamical interactions concurrent with their chemical evolution.

  18. Diversity in in-group bias: structural factors, situational features, and social functions.

    PubMed

    Scheepers, Daan; Spears, Russell; Doosje, Bertjan; Manstead, Antony S R

    2006-06-01

    Four experiments addressed the different forms and functions of in-group bias in different contexts. The authors proposed 2 functions: an identity-expressive function and an instrumental function (or promotion of positive social change). The authors manipulated status differentials, the stability of these differences, and the communication context (intra- vs. intergroup) and measured in-group bias and both functions. As predicted, identity expression via in-group bias on symbolic measures was most important for stable, high-status groups. By contrast, material in-group bias for instrumental motives was most prevalent in unstable, low-status groups but only when communicating with in-group members. This latter effect illustrates the strategic adaptation of group behavior to audience (i.e., displaying in-group bias may provoke the out-group and be counterproductive in instrumental terms). Stable, low-status groups displayed more extreme forms of in-group bias for instrumental reasons regardless of communication context (i.e., they had nothing to lose). Results are discussed in terms of a contextual-functional approach to in-group bias.

  19. Group structure and weighting function effects on neutron penetration through thick sodium-iron shields

    SciTech Connect

    Fu, C.Y.; Ingersoll, D.T.

    1987-01-01

    The effects of group structures and weighting functions on neutron penetration through a thick Na-Fe geometry are studied. The recommended broad-group (61-neutron/23-gamma-ray) and few-group (22-neutron/10-gamma-ray) structures are tailored to the sodium and iron resonances, windows, and capture gamma-ray spectra. The best weighting functions are shown to be fine-group fluxes selected from a few key locations in the geometry. These group structures and weighting functions, relative to existing group structures and conventional weighting functions, improve the accuracy of the computed 61-neutron-group Bonner ball responses by up to one hundred percent and of the computed 22-neutron-group results by up to six hundred percent.

  20. Use of the Nosyl Group as a Functional Protecting Group in Applications of a Michael/Smiles Tandem Process.

    PubMed

    Coulibali, Siomenan; Godou, Timothé; Canesi, Sylvain

    2016-09-01

    Concise preparations of elaborated polycyclic and heterocyclic systems present in natural products were obtained using the nosyl group as a functional protecting group not only to mask the reactivity of a sensitive moiety but also to provide a structure desired in the final target. The group is transferred to the substrate during deprotection through a novel extension of the Truce-Smiles rearrangement in tandem with a 1,4-addition. This strategy provides access to a ring system laden with valuable functionalities for subsequent manipulations and can serve as a versatile building block for the construction of more complex molecular architectures such as indoles in a manner compatible with the concepts of green chemistry and atom economy. PMID:27513700

  1. Functional Groups Based on Leaf Physiology: Are they Spatially and Temporally Robust?

    NASA Technical Reports Server (NTRS)

    Foster, Tammy E.; Brooks, J. Renee; Quincy, Charles (Technical Monitor)

    2002-01-01

    The functional grouping hypothesis, which suggests that complexity in function can be simplified by grouping species with similar responses, was tested in the Florida scrub habitat. Functional groups were identified based on how species in fire maintained FL scrub function in terms of carbon, water and nitrogen dynamics. The suite of physiologic parameters measured to determine function included both instantaneous gas exchange measurements obtained from photosynthetic light response curves and integrated measures of function. Using cluster analysis, five distinct physiologically-based functional groups were identified. Using non-parametric multivariate analyses, it was determined that these five groupings were not altered by plot differences or by the three different management regimes; prescribed burn, mechanically treated and burn, and fire-suppressed. The physiological groupings also remained robust between the two years 1999 and 2000. In order for these groupings to be of use for scaling ecosystem processes, there needs to be an easy-to-measure morphological indicator of function. Life form classifications were able to depict the physiological groupings more adequately than either specific leaf area or leaf thickness. THe ability of life forms to depict the groupings was improved by separating the parasitic Ximenia americana from the shrub category.

  2. [Response of Phytoplankton Functional Groups to Eutrophication in Summer at Xiaoguan Reservoir].

    PubMed

    Li, Lei; Li, Qiu-hua; Jiao, Shu-lin; Li, Yue; Xiao, Jing; Deng, Long; Sun, Rong-guo; Gao, Yong-chun; Luo, Lan

    2015-12-01

    Hydrology and Water Resources Bureau of Guizhou Province, Guiyang 550002, China) Abstract: In order to explore the distribution characteristics of phytoplankton functional groups, eutrophication characteristics and response of phytoplankton functional groups to eutrophication in Xiaoguan Reservoir, phytoplankton and water samples were taken once a week from 25th July 2014 to 27th September 2014. The results showed that there were 22 phytoplankton functional groups, groups S1, D, J, B, G, MP, L₀, SN, X1, Y, Xph, F, T and W1 were comparatively common functional groups, Wherein, S1, D and J were the dominant functional groups. Weekly dynamics of phytoplankton functional groups were: S1-->S1-->S1-->S1-->S1--S1-->S1-->J/D/S1-->Sl1- >/1D. group Sl1dominated over other groups, the cell abundance of S1 appeared two peaks at week 5 and week 7 respectively, but there was a slump at week 8, and rose again at last, compared to two peaks before, the cell abundance had dropped from 10⁸cells · L⁻¹ to 10⁷cells · L⁻¹ Water flush caused by discharge gate opening artificially was the main reason. Based on the three methods of eutrophication evaluation, the water was in moderately eutrophic and eutrophic states in Xiaoguan Reservoir in the summer of 2014. Multivariate analysis (RDA) indicated transparency was the main factor affecting the distribution of phytoplankton functional groups, and nutrients were no longer the limiting factor. The study suggested that phytoplankton functional groups could make a good response to eutrophication: groups S1 and J adapted to the turbid eutrophic water bodies, D adapted to shallow turbid waters and was sensitive to nutrient depletion. Also, common functional groups like G, X1, WW1 F etc. mostly adapted to eutrophic water bodies.

  3. Structure and function studies on enzymes with a catalytic carboxyl group(s): from ribonuclease T1 to carboxyl peptidases

    PubMed Central

    TAKAHASHI, Kenji

    2013-01-01

    A group of enzymes, mostly hydrolases or certain transferases, utilize one or a few side-chain carboxyl groups of Asp and/or Glu as part of the catalytic machinery at their active sites. This review follows mainly the trail of studies performed by the author and his colleagues on the structure and function of such enzymes, starting from ribonuclease T1, then extending to three major types of carboxyl peptidases including aspartic peptidases, glutamic peptidases and serine-carboxyl peptidases. PMID:23759941

  4. Geometries of functional group interactions in enzyme-ligand complexes: guides for receptor modelling.

    PubMed

    Tintelnot, M; Andrews, P

    1989-03-01

    An approach is described which makes use of X-ray structural data from enzyme-ligand complexes in order to obtain information for application in receptor modelling. The atomic surroundings of five different ligand functional groups were determined for all complex structures recorded in the Brookhaven Protein Data Bank. These atomic surroundings were then superimposed with respect to the atoms of the functional groups of the ligands in order to obtain clouds of neighbouring atoms. General principles were sought to describe the orientation or favoured position of groups or atoms around those functional groups when bound to a macromolecule. Some simple conclusions and leads for further modelling were thus derived.

  5. Macroevolutionary trends of atomic composition and related functional group proportion in eukaryotic and prokaryotic proteins.

    PubMed

    Zhang, Yu-Juan; Yang, Chun-Lin; Hao, You-Jin; Li, Ying; Chen, Bin; Wen, Jian-Fan

    2014-01-25

    To fully explore the trends of atomic composition during the macroevolution from prokaryote to eukaryote, five atoms (oxygen, sulfur, nitrogen, carbon, hydrogen) and related functional groups in prokaryotic and eukaryotic proteins were surveyed and compared. Genome-wide analysis showed that eukaryotic proteins have more oxygen, sulfur and nitrogen atoms than prokaryotes do. Clusters of Orthologous Groups (COG) analysis revealed that oxygen, sulfur, carbon and hydrogen frequencies are higher in eukaryotic proteins than in their prokaryotic orthologs. Furthermore, functional group analysis demonstrated that eukaryotic proteins tend to have higher proportions of sulfhydryl, hydroxyl and acylamino, but lower of sulfide and carboxyl. Taken together, an apparent trend of increase was observed for oxygen and sulfur atoms in the macroevolution; the variation of oxygen and sulfur compositions and their related functional groups in macroevolution made eukaryotic proteins carry more useful functional groups. These results will be helpful for better understanding the functional significances of atomic composition evolution.

  6. Biogeographical boundaries, functional group structure and diversity of Rocky Shore communities along the Argentinean coast.

    PubMed

    Wieters, Evie A; McQuaid, Christopher; Palomo, Gabriela; Pappalardo, Paula; Navarrete, Sergio A

    2012-01-01

    We investigate the extent to which functional structure and spatial variability of intertidal communities coincide with major biogeographical boundaries, areas where extensive compositional changes in the biota are observed over a limited geographic extension. We then investigate whether spatial variation in the biomass of functional groups, over geographic (10's km) and local (10's m) scales, could be associated to species diversity within and among these groups. Functional community structure expressed as abundance (density, cover and biomass) and composition of major functional groups was quantified through field surveys at 20 rocky intertidal shores spanning six degrees of latitude along the southwest Atlantic coast of Argentina and extending across the boundaries between the Argentinean and Magellanic Provinces. Patterns of abundance of individual functional groups were not uniformly matched with biogeographical regions. Only ephemeral algae showed an abrupt geographical discontinuity coincident with changes in biogeographic boundaries, and this was limited to the mid intertidal zone. We identified 3-4 main 'groups' of sites in terms of the total and relative abundance of the major functional groups, but these did not coincide with biogeographical boundaries, nor did they follow latitudinal arrangement. Thus, processes that determine the functional structure of these intertidal communities are insensitive to biogeographical boundaries. Over both geographical and local spatial scales, and for most functional groups and tidal levels, increases in species richness within the functional group was significantly associated to increased total biomass and reduced spatial variability of the group. These results suggest that species belonging to the same functional group are sufficiently uncorrelated over space (i.e. metres and site-to-site ) to stabilize patterns of biomass variability and, in this manner, provide a buffer, or "insurance", against spatial variability

  7. Use of the Sequence Rule for Indexing Functional Groups in Organic Compounds

    ERIC Educational Resources Information Center

    Hudrlik, Paul F.

    1973-01-01

    A new method of indexing functional groups in organic compounds is described, utilizing the Cahn-Ingold-Prelog sequence rule. Functional carbon atoms are first classified by functionality, a measure of the oxidation state, then ordered by means of a modified sequence rule. Substructure searching and other applications are discussed. (30…

  8. Biogeographical Boundaries, Functional Group Structure and Diversity of Rocky Shore Communities along the Argentinean Coast

    PubMed Central

    Wieters, Evie A.; McQuaid, Christopher; Palomo, Gabriela; Pappalardo, Paula; Navarrete, Sergio A.

    2012-01-01

    We investigate the extent to which functional structure and spatial variability of intertidal communities coincide with major biogeographical boundaries, areas where extensive compositional changes in the biota are observed over a limited geographic extension. We then investigate whether spatial variation in the biomass of functional groups, over geographic (10′s km) and local (10′s m) scales, could be associated to species diversity within and among these groups. Functional community structure expressed as abundance (density, cover and biomass) and composition of major functional groups was quantified through field surveys at 20 rocky intertidal shores spanning six degrees of latitude along the southwest Atlantic coast of Argentina and extending across the boundaries between the Argentinean and Magellanic Provinces. Patterns of abundance of individual functional groups were not uniformly matched with biogeographical regions. Only ephemeral algae showed an abrupt geographical discontinuity coincident with changes in biogeographic boundaries, and this was limited to the mid intertidal zone. We identified 3–4 main ‘groups’ of sites in terms of the total and relative abundance of the major functional groups, but these did not coincide with biogeographical boundaries, nor did they follow latitudinal arrangement. Thus, processes that determine the functional structure of these intertidal communities are insensitive to biogeographical boundaries. Over both geographical and local spatial scales, and for most functional groups and tidal levels, increases in species richness within the functional group was significantly associated to increased total biomass and reduced spatial variability of the group. These results suggest that species belonging to the same functional group are sufficiently uncorrelated over space (i.e. metres and site-to-site ) to stabilize patterns of biomass variability and, in this manner, provide a buffer, or “insurance”, against spatial

  9. Succession of phytoplankton functional groups regulated by monsoonal hydrology in a large canyon-shaped reservoir.

    PubMed

    Xiao, Li-Juan; Wang, Tian; Hu, Ren; Han, Bo-Ping; Wang, Sheng; Qian, Xin; Padisák, Judit

    2011-10-15

    Liuxihe reservoir is a deep, monomictic, oligo-mesotrophic canyon-reservoir in the subtropical monsoon climate region of southern China. Phytoplankton functional groups in the reservoir were investigated and a comparison made between the succession observed in 2008, an exceptionally wet year, and 2009, an average year. The reservoir shows strong annual fluctuations in water level caused by monsoon rains and artificial drawdown. Altogether 28 functional groups of phytoplankton were identified, including 79 genera. Twelve of the groups were analyzed in detail using redundancy analysis. Because of the oligo-mesotrophic and P-limited condition of the reservoir, the dominant functional groups were those tolerant of nutrient (phosphorus) deficiency. The predominant functional groups in the succession process were Groups A (Cyclotella with greatest axial linear dimension<10 μm), B (Cyclotella with greatest axial linear dimension>10 μm), LO (Peridinium), LM (Ceratium and Microcystis), E (Dinobryon and Mallomonas), F (Botryococcus), X1 (Ankistrodesmus, Ankyra, Chlorella and Monoraphidium) and X2 (Chlamydomonas and Chroomonas). The development of groups A, B and LO was remarkably seasonal. Group A was dominant during stratification, when characteristic small size and high surface/volume ratio morphology conferred an advantage. Group LO was dominant during dry stratification, when motility was advantageous. Group B plankton exhibited a high relative biomass during periods of reduced euphotic depth and isothermy. Groups LM, E, F, X1 and X2 occasionally exhibited high relative biomasses attributable to specific environmental events (e.g. drawdown, changes in zooplankton community). A greater diversity of phytoplankton functional groups was apparent during isothermy. This study underscores the usefulness of functional algal groups in studying succession in subtropical impoundments, in which phytoplankton succession can be significantly affected by external factors such as

  10. Renormalization group functions for two-dimensional phase transitions: To the problem of singular contributions

    SciTech Connect

    Pogorelov, A. A.; Suslov, I. M.

    2007-08-15

    According to the available publications, the field theoretical renormalization group approach in the two-dimensional case gives the critical exponents that differ from the known exact values. This property is associated with the existence of nonanalytic contributions in the renormalization group functions. The situation is analyzed in this work using a new algorithm for summing divergent series that makes it possible to determine the dependence of the results for the critical exponents on the expansion coefficients for the renormalization group functions. It has been shown that the exact values of all the exponents can be obtained with a reasonable form of the coefficient functions. These functions have small nonmonotonic sections or inflections, which are poorly reproduced in natural interpolations. It is not necessary to assume the existence of singular contributions in the renormalization group functions.

  11. Charge transfer, chemical potentials, and the nature of functional groups: answers from quantum chemical topology.

    PubMed

    Pendás, A Martín; Francisco, E; Blanco, M A

    2007-01-01

    We analyze the response of a quantum group within a molecule to charge transfer by using the interacting quantum atoms approach (IQA), an energy partitioning scheme within the quantum theory of atoms in molecules (QTAM). It is shown that this response lies at the core of the concept of the functional group. The manipulation of fractional electron populations is carried out by using distribution functions for the electron number within the quantum basins. Several test systems are studied to show that similar chemical potential groups are characterized by similar energetic behavior upon interaction with other groups. The origin of the empirical additivity rules for group energies in simple hydrocarbons is also investigated. It turns out to rest on the independent saturation of both the self-energies and the interaction energies of the groups as the size of the chain increases. We also show that our results are compatible with the standard group energies of the QTAM.

  12. Divergence of function in sequence-related groups of Escherichia coli proteins.

    PubMed

    Nahum, L A; Riley, M

    2001-08-01

    The most prominent mechanism of molecular evolution is believed to have been duplication and divergence of genes. Proteins that belong to sequence-related groups in any one organism are candidates to have emerged from such a process and to share a common ancestor. Groups of proteins in Escherichia coli having sequence similarity are mostly composed of proteins with closely related function, but some groups comprise proteins with unrelated functions. In order to understand how function can change while sequences remain similar, we have examined some of these groups in detail. The enzymes analyzed in this work include representatives of amidotransferases, phosphotransferases, decarboxylases, and others. Most sequence-related groups contain enzymes that are in the same classes of Enzyme Commission (EC) numbers. We have concentrated on groups that are heterogeneous in that respect, and also on groups containing more than one enzyme of any pathway. We find that although the EC number may differ, the reaction chemistry of these sequence-related proteins is the same or very similar. Some of these families illustrate how diversification has taken place in evolution, using common features of either reaction chemistry or ligand specificity, or both, to create catalysts for different kinds of biochemical reactions. This information has relevance to the area of functional genomics in which the activities of gene products of unknown reading frames are attributed by analogy to the functions of sequence-related proteins of known function.

  13. Unique determination of the effective potential in terms of renormalization group functions

    SciTech Connect

    Chishtie, F. A.; Hanif, T.; McKeon, D. G. C.; Steele, T. G.

    2008-03-15

    The perturbative effective potential V in the massless {lambda}{phi}{sup 4} model with a global O(N) symmetry is uniquely determined to all orders by the renormalization group functions alone when the Coleman-Weinberg renormalization condition (d{sup 4}V/d{phi}{sup 4})|{sub {phi}}{sub ={mu}}={lambda} is used, where {mu} represents the renormalization scale. Systematic methods are developed to express the n-loop effective potential in the Coleman-Weinberg scheme in terms of the known n-loop minimal-subtraction (MS) renormalization group functions. Moreover, it also proves possible to sum the leading- and subsequent-to-leading-logarithm contributions to V. An essential element of this analysis is a conversion of the renormalization group functions in the Coleman-Weinberg scheme to the renormalization group functions in the MS scheme. As an example, the explicit five-loop effective potential is obtained from the known five-loop MS renormalization group functions and we explicitly sum the leading-logarithm, next-to-leading-logarithm, and further subleading-logarithm contributions to V. Extensions of these results to massless scalar QED are also presented. Because massless scalar QED has two couplings, conversion of the renormalization group functions from the MS scheme to the Coleman-Weinberg scheme requires the use of multiscale renormalization group methods.

  14. Functional Group Compositions of Carbonaceous Materials of Hayabusa-Returned Samples

    NASA Astrophysics Data System (ADS)

    Yabuta, H.; Uesugi, M.; Naraoka, H.; Ito, M.; Kilcoyne, D.; Sandford, S. A.; Kitajima, F.; Mita, H.; Takano, Y.; Yada, T.; Karouji, Y.; Ishibashi, Y.; Okada, T.; Abe, M.

    2014-09-01

    We have analyzed the functional group compositions of the carbonaceous materials of Hayabusa-returned samples by STXM-XANES, in order to identify whether the materials are terrestrial or extraterrestrial.

  15. Controlling surface functionality through generation of thiol groups in a self-assembled monolayer.

    SciTech Connect

    Lud, S. Q.; Neppl, S.; Richter, G.; Bruno, P.; Gruen, D. M.; Jordan, R.; Feulner, P.; Stutzmann, M.; Garrido, J. A.; Materials Science Division; Technische Univ. Munchen

    2010-01-01

    A lithographic method to generate reactive thiol groups on functionalized synthetic diamond for biosensor and molecular electronic applications is developed. We demonstrate that ultrananocrystalline diamond (UNCD) thin films covalently functionalized with surface-generated thiol groups allow controlled thiol-disulfide exchange surface hybridization processes. The generation of the thiol functional head groups was obtained by irradiating phenylsulfonic acid (PSA) monolayers on UNCD surfaces. The conversion of the functional headgroup of the self-assembled monolayer was verified by using X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS), and fluorescence microscopy. Our findings indicate the selective generation of reactive thiol surface groups. Furthermore, we demonstrate the grafting of yeast cytochrome c to the thiol-modified diamond surface and the electron transfer between protein and electrode.

  16. Production of Printed Indexes of Chemical Reactions. I. Analysis of Functional Group Interconversions

    ERIC Educational Resources Information Center

    Clinging, R.; Lynch, M. F.

    1973-01-01

    A program is described which identifies functional group interconversion reactions, hydrogenations, and dehydrogenations in a data base containing structures encoded as Wiswesser Line Notations. Production of the data base is briefly described. (17 references) (Authors)

  17. Stability domain of alumina thermally grown on Fe-Cr-Al-based model alloys and modified surface layers exposed to oxygen-containing molten Pb

    NASA Astrophysics Data System (ADS)

    Jianu, A.; Fetzer, R.; Weisenburger, A.; Doyle, S.; Bruns, M.; Heinzel, A.; Hosemann, P.; Mueller, G.

    2016-03-01

    The paper gives experimental results concerning the morphology, composition, structure and thickness of the oxide scales grown on Fe-Cr-Al-based bulk alloys during exposure to oxygen-containing molten lead. The results are discussed and compared with former results obtained on Al-containing surface layers, modified by melting with intense pulsed electron beam and exposed to similar conditions. The present and previous results provide the alumina stability domain and also the criterion of the Al/Cr ratio for the formation of a highly protective alumina layer on the surface of Fe-Cr-Al-based alloys and on modified surface layers exposed to molten lead with 10-6 wt.% oxygen at 400-600 °C. The protective oxide scales, grown on alumina-forming Fe-Cr-Al alloys under the given experimental conditions, were transient aluminas, namely, kappa-Al2O3 and theta-Al2O3.

  18. Multiple-Group Noncompensatory Differential Item Functioning in Raju's Differential Functioning of Items and Tests

    ERIC Educational Resources Information Center

    Oshima, T. C.; Wright, Keith; White, Nick

    2015-01-01

    Raju, van der Linden, and Fleer (1995) introduced a framework for differential functioning of items and tests (DFIT) for unidimensional dichotomous models. Since then, DFIT has been shown to be a quite versatile framework as it can handle polytomous as well as multidimensional models both at the item and test levels. However, DFIT is still limited…

  19. Evaluation of Assertive Training and Homosexual Guidance Service Groups Designed to Improve Homosexual Functioning

    ERIC Educational Resources Information Center

    Russell, A.; Winkler, R.

    1977-01-01

    It is proposed that clinicians should develop research-based assertiveness training procedures for homosexuals that are designed to facilitate homosexual functioning. Subjects (N=27) were assigned to a behaviorally oriented assertive training group or a non-directive group run by a homosexual guidance service. Self-report measures indicated…

  20. The Use of Language Functions in Mathematical Group Games. Teacher Insights.

    ERIC Educational Resources Information Center

    Black, Carolyn; Huerta, Maria G.

    1994-01-01

    Six group games were introduced into a second-grade bilingual classroom. Children's talk during each game was classified using a modification of Dyson's five language functions (representational, directive, heuristic, personal, and interactional). Group games provided many communication opportunities. Some children tried new communication styles.…

  1. Characteristics of Interactional Management Functions in Group Oral by Japanese Learners of English

    ERIC Educational Resources Information Center

    Negishi, Junko

    2010-01-01

    This study attempted to investigate the characteristics of interaction dynamics in a group oral interaction carried out by Japanese learners of English. The relationship between the participants' language development and interactional management functions (IMFs) was also explored. Oral performance tests in a paired or a small group have recently…

  2. Aggressive and Prosocial Peer Group Functioning: Effects on Children's Social, School, and Psychological Adjustment

    ERIC Educational Resources Information Center

    Chung-Hall, Janet; Chen, Xinyin

    2010-01-01

    This study examined the effects of aggressive and prosocial contexts of peer groups on children's socioemotional and school adjustment. Data on informal peer groups, social functioning, and different aspects of adjustment were collected from multiple sources in a sample of elementary school children (149 boys, 181 girls; M age = 10 years).…

  3. Identification of Differential Item Functioning in Multiple-Group Settings: A Multivariate Outlier Detection Approach

    ERIC Educational Resources Information Center

    Magis, David; De Boeck, Paul

    2011-01-01

    We focus on the identification of differential item functioning (DIF) when more than two groups of examinees are considered. We propose to consider items as elements of a multivariate space, where DIF items are outlying elements. Following this approach, the situation of multiple groups is a quite natural case. A robust statistics technique is…

  4. Functional Groups Based on Leaf Physiology: Are they Spatially and Temporally Robust?

    NASA Technical Reports Server (NTRS)

    Foster, Tammy E.; Brooks, J. Renee

    2004-01-01

    The functional grouping hypothesis, which suggests that complexity in ecosystem function can be simplified by grouping species with similar responses, was tested in the Florida scrub habitat. Functional groups were identified based on how species in fire maintained Florida scrub regulate exchange of carbon and water with the atmosphere as indicated by both instantaneous gas exchange measurements and integrated measures of function (%N, delta C-13, delta N-15, C-N ratio). Using cluster analysis, five distinct physiologically-based functional groups were identified in the fire maintained scrub. These functional groups were tested to determine if they were robust spatially, temporally, and with management regime. Analysis of Similarities (ANOSIM), a non-parametric multivariate analysis, indicated that these five physiologically-based groupings were not altered by plot differences (R = -0.115, p = 0.893) or by the three different management regimes; prescribed burn, mechanically treated and burn, and fire-suppressed (R = 0.018, p = 0.349). The physiological groupings also remained robust between the two climatically different years 1999 and 2000 (R = -0.027, p = 0.725). Easy-to-measure morphological characteristics indicating functional groups would be more practical for scaling and modeling ecosystem processes than detailed gas-exchange measurements, therefore we tested a variety of morphological characteristics as functional indicators. A combination of non-parametric multivariate techniques (Hierarchical cluster analysis, non-metric Multi-Dimensional Scaling, and ANOSIM) were used to compare the ability of life form, leaf thickness, and specific leaf area classifications to identify the physiologically-based functional groups. Life form classifications (ANOSIM; R = 0.629, p 0.001) were able to depict the physiological groupings more adequately than either specific leaf area (ANOSIM; R = 0.426, p = 0.001) or leaf thickness (ANOSIM; R 0.344, p 0.001). The ability of

  5. Percolation galaxy groups and clusters in the sdss redshift survey: identification, catalogs, and the multiplicity function

    SciTech Connect

    Berlind, Andreas A.; Frieman, Joshua A.; Weinberg, David H.; Blanton, Michael R.; Warren, Michael S.; Abazajian, Kevork; Scranton, Ryan; Hogg, David W.; Scoccimarro, Roman; Bahcall, Neta A.; Brinkmann, J.; Gott, J.Richard, III; Kleinman, S.J.; Krzesinski, J.; Lee, Brian C.; Miller, Christopher J.; Nitta, Atsuko; Schneider, Donald P.; Tucker, Douglas L.; Zehavi, Idit; /CCPP, New York /Chicago U., Astron. Astrophys. Ctr. /Ohio State U., Dept. Astron. /Los Alamos /Pittsburgh U. /Princeton U. /Subaru Telescope /Apache Point Observ. /Mt. Suhora Observ., Cracow /LBL, Berkeley /Cerro-Tololo InterAmerican Obs. /Penn State U., Astron. Astrophys. /Fermilab /Arizona U., Astron. Dept. - Steward Observ. /Case Western Reserve U.

    2006-01-01

    We identify galaxy groups and clusters in volume-limited samples of the SDSS redshift survey, using a redshift-space friends-of-friends algorithm. We optimize the friends-of-friends linking lengths to recover galaxy systems that occupy the same dark matter halos, using a set of mock catalogs created by populating halos of N-body simulations with galaxies. Extensive tests with these mock catalogs show that no combination of perpendicular and line-of-sight linking lengths is able to yield groups and clusters that simultaneously recover the true halo multiplicity function, projected size distribution, and velocity dispersion. We adopt a linking length combination that yields, for galaxy groups with ten or more members: a group multiplicity function that is unbiased with respect to the true halo multiplicity function; an unbiased median relation between the multiplicities of groups and their associated halos; a spurious group fraction of less than {approx}1%; a halo completeness of more than {approx}97%; the correct projected size distribution as a function of multiplicity; and a velocity dispersion distribution that is {approx}20% too low at all multiplicities. These results hold over a range of mock catalogs that use different input recipes of populating halos with galaxies. We apply our group-finding algorithm to the SDSS data and obtain three group and cluster catalogs for three volume-limited samples that cover 3495.1 square degrees on the sky. We correct for incompleteness caused by fiber collisions and survey edges, and obtain measurements of the group multiplicity function, with errors calculated from realistic mock catalogs. These multiplicity function measurements provide a key constraint on the relation between galaxy populations and dark matter halos.

  6. Stabilization and strengthening effects of functional groups in two-dimensional titanium carbide

    NASA Astrophysics Data System (ADS)

    Fu, Z. H.; Zhang, Q. F.; Legut, D.; Si, C.; Germann, T. C.; Lookman, T.; Du, S. Y.; Francisco, J. S.; Zhang, R. F.

    2016-09-01

    Two-dimensional (2D) materials have attracted considerable interest due to their remarkable properties and potential applications for nanoelectronics, electrodes, energy storage devices, among others. However, many well-studied 2D materials lack appreciable conductivity and tunable mechanical strength, limiting their applications in flexible devices. Newly developed MXenes open up the opportunity to design novel flexible conductive electronic materials. Here, using density functional theory (DFT), we investigate systematically the effects of several functional groups on the stabilization, mechanical properties, and electronic structures of a representative MXene. It is found that oxygen possesses the largest adsorption energy as compared to other functional groups, indicating its good thermodynamic stabilization. In comparison with bare and other functionalized titanium carbides, the oxygen functionalized one exhibits the most superior ideal strength; however, the premature softening of the long-wave phonon modes might limit the intrinsic strength for T i3C2O2 . Furthermore, the introduction of functional groups can induce a strong anisotropy under tensile loading. By analyzing the deformation paths and the electronic instability under various loadings, we demonstrate that the unique strengthening by oxygen functional groups is attributed to a significant charge transfer from inner bonds to outer surface ones after functionalization. Our results shed a novel view into exploring a variety of MXenes for their potential applications in flexible electronic and energy storage devices.

  7. Psychosocial functioning in a group of Swedish adults with Asperger syndrome or high-functioning autism.

    PubMed

    Engström, I; Ekström, L; Emilsson, B

    2003-03-01

    This study reports on psychosocial functioning in Swedish adults with Asperger syndrome (AS) or high-functioning autism (HFA). A systematically selected sample of patients and relatives was interviewed concerning their psychosocial situation. The majority was living independently. All persons but one were unemployed. None was married and none had children. Only a few had some kind of partner. Most persons needed a high level of public and/or private support. The overall adjustment was rated good in 12 percent, fair in 75 percent and poor in 12 percent. Adult persons with AS/HFA have extensive need for support from their families and/or society. This information is important in order to provide adequate interventions that are in accordance with the expressed needs of the individuals themselves.

  8. The electrokinetic characterization of gold nanoparticles, functionalized with cationic functional groups, and its' interaction with DNA.

    PubMed

    Lazarus, Geraldine Genevive; Revaprasadu, Neerish; López-Viota, Julián; Singh, Moganavelli

    2014-09-01

    Gold nanoparticles have attracted strong biomedical interest for drug delivery due to their low toxic nature, surface plasmon resonance and capability of increasing the stability of the payload. However, gene transfection represents another important biological application. Considering that cellular barriers keep enclosed their secret to deliver genes using nanoparticles, an important step can be achieved by studying the functionalization of nanoparticles with DNA. In the present contribution the synthesis of nanoparticles consisting of a gold core coated with one or more layers of amino acid (l-lysine), and cationic polyelectrolytes (poly-ethyleneimine and poly-l-lysine) is reported. All nanoparticles were subjected to dynamic light scattering, electrophoretic mobility measurements, UV-vis optical spectrophotometry analysis and transmission electron microscopy imaging. In addition, the adsorption of DNA plasmid (pSGS) with linear and supercoiled configurations was studied for those gold nanoparticles under the most suitable surface modifications. Preliminary results showed that the gold nanoparticles functionalized with poly-ethyleneimine and poly-l-lysine, respectively, and bound to linear DNA configurations, present in absolute value a higher electrophoretic mobility irrespective of the pH of the media, compared to the supercoiled and nicked configuration. The findings from this study suggest that poly-ethyleneimine and poly-l-lysine functionalized gold nanoparticles are biocompatible and may be promising in the chemical design and future optimization of nanostructures for biomedical applications such as gene and drug delivery.

  9. The impact of functional group on the electronic structure of coordination center

    NASA Astrophysics Data System (ADS)

    Hooshmand Gharehbagh, Zahra; L, Duy; Rahman, Talat S.

    While 9, 10 dicyano-anthracene (DCA) forms a coordination network on Cu(111) surface with Cu adatom coordinated by three DCA molecules, its isomers, 9,10-diisocyano-anthracene forms, surprisingly, molecular rows on the same surface. To understand the impact of functional groups on the electronic structure of the coordination center, we have carried out density functional theory based calculations of the electronic structure of a set of naphthalene molecules with different functional groups (N, CN, NC, NH2, COH, COOH) adsorbed on Cu(111), with and without a Cu adatom. Our results show that while the interaction between the naphthalene backbone and the Cu(111) surface is dominated by van der Waals (vdW) forces, in all cases considered the functional group forms a covalent bond with the Cu (ad)atom (on) of the surface. The calculated differential charge redistribution shows that the strongest covalent bond is formed by the NC group, which differs remarkably from that formed by the CN group, while the vdW interaction is very similar in both cases. These results provide insights into the different surface coordination behavior of molecules with above-mentioned functional groups. Work support in part by NSF Grant CHE-1310327.

  10. Classifying proteins into functional groups based on all-versus-all BLAST of 10 million proteins.

    PubMed

    Kolker, Natali; Higdon, Roger; Broomall, William; Stanberry, Larissa; Welch, Dean; Lu, Wei; Haynes, Winston; Barga, Roger; Kolker, Eugene

    2011-01-01

    To address the monumental challenge of assigning function to millions of sequenced proteins, we completed the first of a kind all-versus-all sequence alignments using BLAST for 9.9 million proteins in the UniRef100 database. Microsoft Windows Azure produced over 3 billion filtered records in 6 days using 475 eight-core virtual machines. Protein classification into functional groups was then performed using Hive and custom jars implemented on top of Apache Hadoop utilizing the MapReduce paradigm. First, using the Clusters of Orthologous Genes (COG) database, a length normalized bit score (LNBS) was determined to be the best similarity measure for classification of proteins. LNBS achieved sensitivity and specificity of 98% each. Second, out of 5.1 million bacterial proteins, about two-thirds were assigned to significantly extended COG groups, encompassing 30 times more assigned proteins. Third, the remaining proteins were classified into protein functional groups using an innovative implementation of a single-linkage algorithm on an in-house Hadoop compute cluster. This implementation significantly reduces the run time for nonindexed queries and optimizes efficient clustering on a large scale. The performance was also verified on Amazon Elastic MapReduce. This clustering assigned nearly 2 million proteins to approximately half a million different functional groups. A similar approach was applied to classify 2.8 million eukaryotic sequences resulting in over 1 million proteins being assign to existing KOG groups and the remainder clustered into 100,000 functional groups. PMID:21809957

  11. Interrogating Surface Functional Group Heterogeneity of Activated Thermoplastics Using Super-Resolution Fluorescence Microscopy.

    PubMed

    ONeil, Colleen E; Jackson, Joshua M; Shim, Sang-Hee; Soper, Steven A

    2016-04-01

    We present a novel approach for characterizing surfaces utilizing super-resolution fluorescence microscopy with subdiffraction limit spatial resolution. Thermoplastic surfaces were activated by UV/O3 or O2 plasma treatment under various conditions to generate pendant surface-confined carboxylic acids (-COOH). These surface functional groups were then labeled with a photoswitchable dye and interrogated using single-molecule, localization-based, super-resolution fluorescence microscopy to elucidate the surface heterogeneity of these functional groups across the activated surface. Data indicated nonuniform distributions of these functional groups for both COC and PMMA thermoplastics with the degree of heterogeneity being dose dependent. In addition, COC demonstrated relative higher surface density of functional groups compared to PMMA for both UV/O3 and O2 plasma treatment. The spatial distribution of -COOH groups secured from super-resolution imaging were used to simulate nonuniform patterns of electroosmotic flow in thermoplastic nanochannels. Simulations were compared to single-particle tracking of fluorescent nanoparticles within thermoplastic nanoslits to demonstrate the effects of surface functional group heterogeneity on the electrokinetic transport process.

  12. GPU-based parallel group ICA for functional magnetic resonance data.

    PubMed

    Jing, Yanshan; Zeng, Weiming; Wang, Nizhuan; Ren, Tianlong; Shi, Yingchao; Yin, Jun; Xu, Qi

    2015-04-01

    The goal of our study is to develop a fast parallel implementation of group independent component analysis (ICA) for functional magnetic resonance imaging (fMRI) data using graphics processing units (GPU). Though ICA has become a standard method to identify brain functional connectivity of the fMRI data, it is computationally intensive, especially has a huge cost for the group data analysis. GPU with higher parallel computation power and lower cost are used for general purpose computing, which could contribute to fMRI data analysis significantly. In this study, a parallel group ICA (PGICA) on GPU, mainly consisting of GPU-based PCA using SVD and Infomax-ICA, is presented. In comparison to the serial group ICA, the proposed method demonstrated both significant speedup with 6-11 times and comparable accuracy of functional networks in our experiments. This proposed method is expected to perform the real-time post-processing for fMRI data analysis.

  13. Identifying organic aerosol sources by comparing functional group composition in chamber and atmospheric particles.

    PubMed

    Russell, Lynn M; Bahadur, Ranjit; Ziemann, Paul J

    2011-03-01

    Measurements of submicron particles by Fourier transform infrared spectroscopy in 14 campaigns in North America, Asia, South America, and Europe were used to identify characteristic organic functional group compositions of fuel combustion, terrestrial vegetation, and ocean bubble bursting sources, each of which often accounts for more than a third of organic mass (OM), and some of which is secondary organic aerosol (SOA) from gas-phase precursors. The majority of the OM consists of alkane, carboxylic acid, hydroxyl, and carbonyl groups. The organic functional groups formed from combustion and vegetation emissions are similar to the secondary products identified in chamber studies. The near absence of carbonyl groups in the observed SOA associated with combustion is consistent with alkane rather than aromatic precursors, and the absence of organonitrate groups can be explained by their hydrolysis in humid ambient conditions. The remote forest observations have ratios of carboxylic acid, organic hydroxyl, and nonacid carbonyl groups similar to those observed for isoprene and monoterpene chamber studies, but in biogenic aerosols transported downwind of urban areas the formation of esters replaces the acid and hydroxyl groups and leaves only nonacid carbonyl groups. The carbonyl groups in SOA associated with vegetation emissions provides striking evidence for the mechanism of esterification as the pathway for possible oligomerization reactions in the atmosphere. Forest fires include biogenic emissions that produce SOA with organic components similar to isoprene and monoterpene chamber studies, also resulting in nonacid carbonyl groups in SOA.

  14. Identifying organic aerosol sources by comparing functional group composition in chamber and atmospheric particles

    PubMed Central

    Russell, Lynn M.; Bahadur, Ranjit; Ziemann, Paul J.

    2011-01-01

    Measurements of submicron particles by Fourier transform infrared spectroscopy in 14 campaigns in North America, Asia, South America, and Europe were used to identify characteristic organic functional group compositions of fuel combustion, terrestrial vegetation, and ocean bubble bursting sources, each of which often accounts for more than a third of organic mass (OM), and some of which is secondary organic aerosol (SOA) from gas-phase precursors. The majority of the OM consists of alkane, carboxylic acid, hydroxyl, and carbonyl groups. The organic functional groups formed from combustion and vegetation emissions are similar to the secondary products identified in chamber studies. The near absence of carbonyl groups in the observed SOA associated with combustion is consistent with alkane rather than aromatic precursors, and the absence of organonitrate groups can be explained by their hydrolysis in humid ambient conditions. The remote forest observations have ratios of carboxylic acid, organic hydroxyl, and nonacid carbonyl groups similar to those observed for isoprene and monoterpene chamber studies, but in biogenic aerosols transported downwind of urban areas the formation of esters replaces the acid and hydroxyl groups and leaves only nonacid carbonyl groups. The carbonyl groups in SOA associated with vegetation emissions provides striking evidence for the mechanism of esterification as the pathway for possible oligomerization reactions in the atmosphere. Forest fires include biogenic emissions that produce SOA with organic components similar to isoprene and monoterpene chamber studies, also resulting in nonacid carbonyl groups in SOA. PMID:21317360

  15. Subtle cytotoxicity and genotoxicity differences in superparamagnetic iron oxide nanoparticles coated with various functional groups

    PubMed Central

    Hong, Seong Cheol; Lee, Jong Ho; Lee, Jaewook; Kim, Hyeon Yong; Park, Jung Youn; Cho, Johann; Lee, Jaebeom; Han, Dong-Wook

    2011-01-01

    Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely utilized for the diagnosis and therapy of specific diseases, as magnetic resonance imaging (MRI) contrast agents and drug-delivery carriers, due to their easy transportation to targeted areas by an external magnetic field. For such biomedical applications, SPIONs must have multifunctional characteristics, including optimized size and modified surface. However, the biofunctionality and biocompatibility of SPIONs with various surface functional groups of different sizes have yet to be elucidated clearly. Therefore, it is important to carefully monitor the cytotoxicity and genotoxicity of SPIONs that are surfaced-modified with various functional groups of different sizes. In this study, we evaluated SPIONs with diameters of approximately 10 nm and 100~150 nm, containing different surface functional groups. SPIONs were covered with −O− groups, so-called bare SPIONs. Following this, they were modified with three different functional groups – hydroxyl (−OH), carboxylic (−COOH), and amine (−NH2) groups – by coating their surfaces with tetraethyl orthosilicate (TEOS), (3-aminopropyl)trimethoxysilane (APTMS), TEOS-APTMS, or citrate, which imparted different surface charges and sizes to the particles. The effects of SPIONs coated with these functional groups on mitochondrial activity, intracellular accumulation of reactive oxygen species, membrane integrity, and DNA stability in L-929 fibroblasts were determined by water-soluble tetrazolium, 2′,7′-dichlorodihydrofluorescein, lactate dehydrogenase, and comet assays, respectively. Our toxicological observations suggest that the functional groups and sizes of SPIONs are critical determinants of cellular responses, degrees of cytotoxicity and genotoxicity, and potential mechanisms of toxicity. Nanoparticles with various surface modifications and of different sizes induced slight, but possibly meaningful, changes in cell cytotoxicity and

  16. On the psychological function of flags and logos: Group identity symbols increase perceived entitativity.

    PubMed

    Callahan, Shannon P; Ledgerwood, Alison

    2016-04-01

    Group identity symbols such as flags and logos have been widely used across time and cultures, yet researchers know very little about the psychological functions that such symbols can serve. The present research tested the hypotheses that (a) simply having a symbol leads collections of individuals to seem more like real, unified groups, (b) this increased psychological realness leads groups to seem more threatening and effective to others, and (c) group members therefore strategically emphasize symbols when they want their group to appear unified and intimidating. In Studies 1a-1c, participants perceived various task groups as more entitative when they happened to have a symbol. In Study 2, symbols not only helped groups make up for lacking a physical characteristic associated with entitativity (physical similarity), but also led groups to seem more threatening. Study 3 examined the processes underlying this effect and found that group symbols increase entitativity by increasing perceived cohesiveness. Study 4 extended our results to show that symbols not only shape the impressions people form of novel groups, but also change people's existing impressions of more familiar and real-world social groups, making them seem more entitative and competent but also less warm. Finally, Studies 5a and 5b further expand our understanding of the psychological function of symbols by showing that group members strategically display symbols when they are motivated to convey an impression of their group as unified and threatening (vs. inclusive and cooperative). We discuss implications for understanding how group members navigate their social identities. PMID:27078507

  17. Modeling phytoplankton community in reservoirs. A comparison between taxonomic and functional groups-based models.

    PubMed

    Di Maggio, Jimena; Fernández, Carolina; Parodi, Elisa R; Diaz, M Soledad; Estrada, Vanina

    2016-01-01

    In this paper we address the formulation of two mechanistic water quality models that differ in the way the phytoplankton community is described. We carry out parameter estimation subject to differential-algebraic constraints and validation for each model and comparison between models performance. The first approach aggregates phytoplankton species based on their phylogenetic characteristics (Taxonomic group model) and the second one, on their morpho-functional properties following Reynolds' classification (Functional group model). The latter approach takes into account tolerance and sensitivity to environmental conditions. The constrained parameter estimation problems are formulated within an equation oriented framework, with a maximum likelihood objective function. The study site is Paso de las Piedras Reservoir (Argentina), which supplies water for consumption for 450,000 population. Numerical results show that phytoplankton morpho-functional groups more closely represent each species growth requirements within the group. Each model performance is quantitatively assessed by three diagnostic measures. Parameter estimation results for seasonal dynamics of the phytoplankton community and main biogeochemical variables for a one-year time horizon are presented and compared for both models, showing the functional group model enhanced performance. Finally, we explore increasing nutrient loading scenarios and predict their effect on phytoplankton dynamics throughout a one-year time horizon.

  18. Local and Regional Determinants of an Uncommon Functional Group in Freshwater Lakes and Ponds

    PubMed Central

    McCann, Michael James

    2015-01-01

    A combination of local and regional factors and stochastic forces is expected to determine the occurrence of species and the structure of communities. However, in most cases, our understanding is incomplete, with large amounts of unexplained variation. Using functional groups rather than individual species may help explain the relationship between community composition and conditions. In this study, I used survey data from freshwater lakes and ponds to understand factors that determine the presence of the floating plant functional group in the northeast United States. Of the 176 water bodies surveyed, 104 (59.1%) did not contain any floating plant species. The occurrence of this functional group was largely determined by local abiotic conditions, which were spatially autocorrelated across the region. A model predicting the presence of the floating plant functional group performed similarly to the best species-specific models. Using a permutation test, I also found that the observed prevalence of floating plants is no different than expected by random assembly from a species pool of its size. These results suggest that the size of the species pool interacts with local conditions in determining the presence of a functional group. Nevertheless, a large amount of unexplained variation remains, attributable to either stochastic species occurrence or incomplete predictive models. The simple permutation approach in this study can be extended to test alternative models of community assembly. PMID:26121636

  19. Energies of the adsorption of functional groups to calcium carbonate polymorphs: the importance of -OH and -COOH groups.

    PubMed

    Okhrimenko, D V; Nissenbaum, J; Andersson, M P; Olsson, M H M; Stipp, S L S

    2013-09-01

    The adsorption behavior of calcium carbonate is an important factor in many processes in nature, industry, and biological systems. We determined and compared the adsorption energies for a series of small molecules of different sizes and polarities (i.e., water, several alcohols, and acetic acid) on three synthetic CaCO3 polymorphs (calcite, aragonite, and vaterite). We measured isosteric heats of adsorption from vapor adsorption isotherms for 273 < T < 293 K, and we used XRD and SEM to confirm that samples did not change phase during the experiments. Density functional calculations and molecular dynamics simulations complemented the experimental results and aided interpretation. Alcohols with molecular mass greater than that of methanol bind more strongly to the calcium carbonate polymorphs than water and acetic acid. The adsorption energies for the alcohols are typical of chemisorption and indicate alcohol displacement of water from calcium carbonate surfaces. This explains why organisms favor biomolecules that contain alcohol functional groups (-OH) to control which polymorph they use, the crystal face and orientation, and the particle shape and size in biomineralization processes. This new insight is also very useful in understanding organic molecule adsorption mechanisms in soils, sediments, and rocks, which is important for predicting the behavior of mineral-fluid interactions when the challenge is to remediate contaminated groundwater aquifers or to produce oil and gas from reservoirs.

  20. Linking of Sensor Molecules with Amino Groups to Amino-Functionalized AFM Tips

    PubMed Central

    2011-01-01

    The measuring tip of an atomic force microscope (AFM) can be upgraded to a specific biosensor by attaching one or a few biomolecules to the apex of the tip. The biofunctionalized tip is then used to map cognate target molecules on a sample surface or to study biophysical parameters of interaction with the target molecules. The functionality of tip-bound sensor molecules is greatly enhanced if they are linked via a thin, flexible polymer chain. In a typical scheme of tip functionalization, reactive groups are first generated on the tip surface, a bifunctional cross-linker is then attached with one of its two reactive ends, and finally the probe molecule of interest is coupled to the free end of the cross-linker. Unfortunately, the most popular functional group generated on the tip surface is the amino group, while at the same time, the only useful coupling functions of many biomolecules (such as antibodies) are also NH2 groups. In the past, various tricks or detours were applied to minimize the undesired bivalent reaction of bifunctional linkers with adjacent NH2 groups on the tip surface. In the present study, an uncompromising solution to this problem was found with the help of a new cross-linker (“acetal-PEG-NHS”) which possesses one activated carboxyl group and one acetal-protected benzaldehyde function. The activated carboxyl ensures rapid unilateral attachment to the amino-functionalized tip, and only then is the terminal acetal group converted into the amino-reactive benzaldehyde function by mild treatment (1% citric acid, 1–10 min) which does not harm the AFM tip. As an exception, AFM tips with magnetic coating become demagnetized in 1% citric acid. This problem was solved by deprotecting the acetal group before coupling the PEG linker to the AFM tip. Bivalent binding of the corresponding linker (“aldehyde-PEG-NHS”) to adjacent NH2 groups on the tip was largely suppressed by high linker concentrations. In this way, magnetic AFM tips could be

  1. Carboxyl group (-CO2 H) functionalized coordination polymer nanoparticles as efficient platforms for drug delivery.

    PubMed

    Novio, Fernando; Lorenzo, Julia; Nador, Fabiana; Wnuk, Karolina; Ruiz-Molina, Daniel

    2014-11-17

    Functionalization of nanoparticles can significantly influence their properties and potential applications. Although researchers can now functionalize metal, metal oxide, and organic polymer nanoparticles with a high degree of precision, controlled surface functionalization of nanoscale coordination polymer particles (CPPs) has remained a significant challenge. The lack of methodology is perhaps one of the greatest roadblocks to the advancement of CPPs into high added-value drug delivery applications. Here, we report having achieved this goal through a stepwise formation and functionalization protocol. We fabricated robust nanoparticles with enhanced thermal and colloidal stabilities by incorporation of carboxyl groups and these surface carboxyl groups could be subsequently functionalized through well-known peptide coupling reactions. The set of chemistries that we employed as proof-of-concept enabled a plethora of new functional improvements for the application of CPPs as drug delivery carriers, including enhanced colloidal stabilities and the incorporation of additional functional groups such as polyethylene glycol (PEG) or fluorescent dyes that enabled tracking of their cellular uptake. Finally, we ascertained the cytotoxicity of the new CPP nanoparticles loaded with camptothecin to human breast adenocarcinoma (MCF-7). Efflux measurements show that the encapsulation of camptothecin enhances the potency of the drug 6.5-fold and increases the drug retention within the cell. PMID:25284328

  2. Carboxyl group (-CO2 H) functionalized coordination polymer nanoparticles as efficient platforms for drug delivery.

    PubMed

    Novio, Fernando; Lorenzo, Julia; Nador, Fabiana; Wnuk, Karolina; Ruiz-Molina, Daniel

    2014-11-17

    Functionalization of nanoparticles can significantly influence their properties and potential applications. Although researchers can now functionalize metal, metal oxide, and organic polymer nanoparticles with a high degree of precision, controlled surface functionalization of nanoscale coordination polymer particles (CPPs) has remained a significant challenge. The lack of methodology is perhaps one of the greatest roadblocks to the advancement of CPPs into high added-value drug delivery applications. Here, we report having achieved this goal through a stepwise formation and functionalization protocol. We fabricated robust nanoparticles with enhanced thermal and colloidal stabilities by incorporation of carboxyl groups and these surface carboxyl groups could be subsequently functionalized through well-known peptide coupling reactions. The set of chemistries that we employed as proof-of-concept enabled a plethora of new functional improvements for the application of CPPs as drug delivery carriers, including enhanced colloidal stabilities and the incorporation of additional functional groups such as polyethylene glycol (PEG) or fluorescent dyes that enabled tracking of their cellular uptake. Finally, we ascertained the cytotoxicity of the new CPP nanoparticles loaded with camptothecin to human breast adenocarcinoma (MCF-7). Efflux measurements show that the encapsulation of camptothecin enhances the potency of the drug 6.5-fold and increases the drug retention within the cell.

  3. Assessment of female sexual function in a group of uncircumcised obese Egyptian women.

    PubMed

    Elnashar, A R M; Ibrahim, N H; Ahmed, H-Eh; Hassanin, A M; Elgawady, M A

    2015-01-01

    The aim of the present study was to assess female sexual function in an obese group (250 women) and to compare it with a control group (100 women), among 25-35-year-old uncircumcised Egyptian women, using female sexual function index (FSFI) score. FSFI total score of ⩽ 26.55 was considered diagnostic of Female Sexual Dysfunction (FSD). The percentage of FSD in the obese group was 73.6% while it was 71% in the control group, which was statistically insignificant (P > 0.05). The difference between both groups regarding the total (FSFI) score was insignificant (P > 0.05), but arousal and satisfaction domains scores were significantly lower in the obese group. In the obese group, a strong negative correlation between body mass index and arousal, orgasm and the total FSFI score was found. Women with excessive obesity had the lowest total FSFI score. In the obese group, college graduates had the highest total scores and all domain scores of FSFI followed by high school graduates while the least educated women had the lowest scores and when these subgroups were compared, significant differences were found among them. We conclude that in uncircumcised 25-35-year-old Egyptian women, obesity is not a major detrimental factor for FSD, but it may affect some sexual domains such as arousal and satisfaction, although excessive obesity is associated with FSD. Also, educational and cultural factors may have an impact on perception of sex and pleasure. PMID:26155831

  4. Wigner functions for noncommutative quantum mechanics: A group representation based construction

    SciTech Connect

    Chowdhury, S. Hasibul Hassan; Ali, S. Twareque

    2015-12-15

    This paper is devoted to the construction and analysis of the Wigner functions for noncommutative quantum mechanics, their marginal distributions, and star-products, following a technique developed earlier, viz, using the unitary irreducible representations of the group G{sub NC}, which is the three fold central extension of the Abelian group of ℝ{sup 4}. These representations have been exhaustively studied in earlier papers. The group G{sub NC} is identified with the kinematical symmetry group of noncommutative quantum mechanics of a system with two degrees of freedom. The Wigner functions studied here reflect different levels of non-commutativity—both the operators of position and those of momentum not commuting, the position operators not commuting and finally, the case of standard quantum mechanics, obeying the canonical commutation relations only.

  5. Porous polymer monoliths with large surface area and functional groups prepared via copolymerization of protected functional monomers and hypercrosslinking.

    PubMed

    Maya, Fernando; Svec, Frantisek

    2013-11-22

    A new approach to the preparation of porous polymer monoliths possessing both large surface area and functional groups has been developed. The chloromethyl groups of poly(styrene-co-4-acetoxystyrene-co-vinylbenzyl chloride-co-divinylbenzene) monolith enable post-polymerization hypercrosslinking catalyzed by ferric chloride in dichloroethane leading to a multitude of small pores thus enhancing the surface area. The acetoxy functionalities are easily deprotected using hydrazine to produce polar phenolic hydroxyl groups, which would be difficult to obtain by direct copolymerization of hydroxyl-containing monomers. The hypercrosslinking and deprotection reactions as well as their sequence were studied in detail with bulk polymer monoliths containing up to 50% 4-acetoxystyrene and its progress monitored by infrared spectrometry and nitrogen adsorption/desorption measurements. No significant difference was found for both possible successions. All monoliths were also prepared in a capillary column format, then deprotected and hypercrosslinked. Capillary columns were tested for the separation of small molecules using reversed phase and normal phase chromatographic modes. For polymer monoliths containing 50% deprotected 4-acetoxystyrene, column efficiencies of 40,000 plates/m for benzene in reversed phase mode and 31,800 plates/m for nitrobenzene in normal phase mode, were obtained. The percentage of hydroxyl groups in the monoliths enables modulation of polarity of the stationary phase. They also represent functionalities that are potentially suitable for further modifications and formation of new types of stationary phases for liquid chromatography.

  6. Functional grouping and cortical–subcortical interactions in emotion: A meta-analysis of neuroimaging studies

    PubMed Central

    Kober, Hedy; Barrett, Lisa Feldman; Joseph, Josh; Bliss-Moreau, Eliza; Lindquist, Kristen; Wager, Tor D.

    2009-01-01

    We performed an updated quantitative meta-analysis of 162 neuroimaging studies of emotion using a novel multi-level kernel-based approach, focusing on locating brain regions consistently activated in emotional tasks and their functional organization into distributed functional groups, independent of semantically defined emotion category labels (e.g., “anger,” “fear”). Such brain-based analyses are critical if our ways of labeling emotions are to be evaluated and revised based on consistency with brain data. Consistent activations were limited to specific cortical sub-regions, including multiple functional areas within medial, orbital, and inferior lateral frontal cortices. Consistent with a wealth of animal literature, multiple subcortical activations were identified, including amygdala, ventral striatum, thalamus, hypothalamus, and periaqueductal gray. We used multivariate parcellation and clustering techniques to identify groups of co-activated brain regions across studies. These analyses identified six distributed functional groups, including medial and lateral frontal groups, two posterior cortical groups, and paralimbic and core limbic/brainstem groups. These functional groups provide information on potential organization of brain regions into large-scale networks. Specific follow-up analyses focused on amygdala, periaqueductal gray (PAG), and hypothalamic (Hy) activations, and identified frontal cortical areas co-activated with these core limbic structures. While multiple areas of frontal cortex co-activated with amygdala sub-regions, a specific region of dorsomedial prefrontal cortex (dmPFC, Brodmann’s Area 9/32) was the only area co-activated with both PAG and Hy. Subsequent mediation analyses were consistent with a pathway from dmPFC through PAG to Hy. These results suggest that medial frontal areas are more closely associated with core limbic activation than their lateral counterparts, and that dmPFC may play a particularly important role in the

  7. Plant diversity and functional groups affect Si and Ca pools in aboveground biomass of grassland systems.

    PubMed

    Schaller, Jörg; Roscher, Christiane; Hillebrand, Helmut; Weigelt, Alexandra; Oelmann, Yvonne; Wilcke, Wolfgang; Ebeling, Anne; Weisser, Wolfgang W

    2016-09-01

    Plant diversity is an important driver of nitrogen and phosphorus stocks in aboveground plant biomass of grassland ecosystems, but plant diversity effects on other elements also important for plant growth are less understood. We tested whether plant species richness, functional group richness or the presence/absence of particular plant functional groups influences the Si and Ca concentrations (mmol g(-1)) and stocks (mmol m(-2)) in aboveground plant biomass in a large grassland biodiversity experiment (Jena Experiment). In the experiment including 60 temperate grassland species, plant diversity was manipulated as sown species richness (1, 2, 4, 8, 16) and richness and identity of plant functional groups (1-4; grasses, small herbs, tall herbs, legumes). We found positive species richness effects on Si as well as Ca stocks that were attributable to increased biomass production. The presence of particular functional groups was the most important factor explaining variation in aboveground Si and Ca stocks (mmol m(-2)). Grass presence increased the Si stocks by 140 % and legume presence increased the Ca stock by 230 %. Both the presence of specific plant functional groups and species diversity altered Si and Ca stocks, whereas Si and Ca concentration were affected mostly by the presence of specific plant functional groups. However, we found a negative effect of species diversity on Si and Ca accumulation, by calculating the deviation between mixtures and mixture biomass proportions, but in monoculture concentrations. These changes may in turn affect ecosystem processes such as plant litter decomposition and nutrient cycling in grasslands.

  8. Functional network organizations of two contrasting temperament groups in dimensions of novelty seeking and harm avoidance.

    PubMed

    Kyeong, Sunghyon; Kim, Eunjoo; Park, Hae-Jeong; Hwang, Dong-Uk

    2014-08-01

    Novelty seeking (NS) and harm avoidance (HA) are two major dimensions of temperament in Cloninger׳s neurobiological model of personality. Previous neurofunctional and biological studies on temperament dimensions of HA and NS suggested that the temperamental traits have significant correlations with cortical and subcortical brain regions. However, no study to date has investigated the functional network modular organization as a function of the temperament dimension. The temperament dimensions were originally proposed to be independent of one another. However, a meta-analysis based on 16 published articles found a significant negative correlation between HA and NS (Miettunen et al., 2008). Based on this negative correlation, the current study revealed the whole-brain connectivity modular architecture for two contrasting temperament groups. The k-means clustering algorithm, with the temperamental traits of HA and NS as an input, was applied to divide the 40 subjects into two temperament groups: 'high HA and low NS' versus 'low HA and high NS'. Using the graph theoretical framework, we found a functional segregation of whole brain network architectures derived from resting-state functional MRI. In the 'high HA and low NS' group, the regulatory brain regions, such as the prefrontal cortex (PFC), are clustered together with the limbic system. In the 'low HA and high NS' group, however, brain regions lying on the dopaminergic pathways, such as the PFC and basal ganglia, are partitioned together. These findings suggest that the neural basis of inhibited, passive, and inactive behaviors in the 'high HA and low NS' group was derived from the increased network associations between the PFC and limbic clusters. In addition, supporting evidence of topological differences between the two temperament groups was found by analyzing the functional connectivity density and gray matter volume, and by computing the relationships between the morphometry and function of the brain.

  9. Plant diversity and functional groups affect Si and Ca pools in aboveground biomass of grassland systems.

    PubMed

    Schaller, Jörg; Roscher, Christiane; Hillebrand, Helmut; Weigelt, Alexandra; Oelmann, Yvonne; Wilcke, Wolfgang; Ebeling, Anne; Weisser, Wolfgang W

    2016-09-01

    Plant diversity is an important driver of nitrogen and phosphorus stocks in aboveground plant biomass of grassland ecosystems, but plant diversity effects on other elements also important for plant growth are less understood. We tested whether plant species richness, functional group richness or the presence/absence of particular plant functional groups influences the Si and Ca concentrations (mmol g(-1)) and stocks (mmol m(-2)) in aboveground plant biomass in a large grassland biodiversity experiment (Jena Experiment). In the experiment including 60 temperate grassland species, plant diversity was manipulated as sown species richness (1, 2, 4, 8, 16) and richness and identity of plant functional groups (1-4; grasses, small herbs, tall herbs, legumes). We found positive species richness effects on Si as well as Ca stocks that were attributable to increased biomass production. The presence of particular functional groups was the most important factor explaining variation in aboveground Si and Ca stocks (mmol m(-2)). Grass presence increased the Si stocks by 140 % and legume presence increased the Ca stock by 230 %. Both the presence of specific plant functional groups and species diversity altered Si and Ca stocks, whereas Si and Ca concentration were affected mostly by the presence of specific plant functional groups. However, we found a negative effect of species diversity on Si and Ca accumulation, by calculating the deviation between mixtures and mixture biomass proportions, but in monoculture concentrations. These changes may in turn affect ecosystem processes such as plant litter decomposition and nutrient cycling in grasslands. PMID:27164912

  10. A Simple and Versatile Amide Directing Group for C-H Functionalizations.

    PubMed

    Zhu, Ru-Yi; Farmer, Marcus E; Chen, Yan-Qiao; Yu, Jin-Quan

    2016-08-26

    Achieving selective C-H activation at a single and strategic site in the presence of multiple C-H bonds can provide a powerful and generally useful retrosynthetic disconnection. In this context, a directing group serves as a compass to guide the transition metal to C-H bonds by using distance and geometry as powerful recognition parameters to distinguish between proximal and distal C-H bonds. However, the installation and removal of directing groups is a practical drawback. To improve the utility of this approach, one can seek solutions in three directions: 1) Simplifying the directing group, 2) using common functional groups or protecting groups as directing groups, and 3) attaching the directing group to substrates via a transient covalent bond to render the directing group catalytic. This Review describes the rational development of an extremely simple and yet broadly applicable directing group for Pd(II) , Rh(III) , and Ru(II) catalysts, namely the N-methoxy amide (CONHOMe) moiety. Through collective efforts in the community, a wide range of C-H activation transformations using this type of simple directing group have been developed. PMID:27479708

  11. Pyrrolic tripodal receptors for carbohydrates. Role of functional groups and binding geometry on carbohydrate recognition.

    PubMed

    Cacciarini, Martina; Nativi, Cristina; Norcini, Martina; Staderini, Samuele; Francesconi, Oscar; Roelens, Stefano

    2011-02-21

    The contribution from several H-bonding groups and the impact of geometric requirements on the binding ability of benzene-based tripodal receptors toward carbohydrates have been investigated by measuring the affinity of a set of structures toward octyl β-D-glucopyranoside, selected as a representative monosaccharide. The results reported in the present study demonstrate that a judicious choice of correct geometry and appropriate functional groups is critical to achieve the complementary hydrogen bonding interactions required for an effective carbohydrate recognition.

  12. Designed nitrogen doping of few-layer graphene functionalized by selective oxygenic groups

    PubMed Central

    2014-01-01

    Few-layer nitrogen doped graphene was synthesized originating from graphene oxide functionalized by selective oxygenic functional groups (hydroxyl, carbonyl, carboxyl etc.) under hydrothermal conditions, respectively. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) observation evidenced few-layer feature of the graphene oxide. X-ray diffraction (XRD) pattern confirmed phase structure of the graphene oxide and reduced graphene oxide. Nitrogen doping content and bonding configuration of the graphene was determined by X-ray photoelectron spectroscopy (XPS), which indicated that different oxygenic functional groups were evidently different in affecting the nitrogen doping process. Compared with other oxygenic groups, carboxyl group played a crucial role in the initial stage of nitrogen doping while hydroxyls exhibited more evident contribution to the doping process in the late stage of the reaction. Formation of graphitic-like nitrogen species was controlled by a synergistic effect of the involved oxygenic groups (e.g., -COOH, -OH, C-O-C, etc.). The doping mechanism of nitrogen in the graphene was scrutinized. The research in this work may not only contribute to the fundamental understandings of nitrogen doping within graphene but promote the development of producing novel graphene-based devices with designed surface functionalization. PMID:25520594

  13. The Effect of Functional Groups in Bio-Derived Fuel Candidates.

    PubMed

    Jenkins, Rhodri W; Moore, Cameron M; Semelsberger, Troy A; Chuck, Christopher J; Gordon, John C; Sutton, Andrew D

    2016-05-10

    Interest in developing renewable fuels is continuing to grow and biomass represents a viable source of renewable carbon with which to replace fossil-based components in transportation fuels. During our own work, we noticed that chemists think in terms of functional groups whereas fuel engineers think in terms of physical fuel properties. In this Concept article, we discuss the effect of carbon and oxygen functional groups on potential fuel properties. This serves as a way of informing our own thinking and provides us with a basis with which to design and synthesize molecules from biomass that could provide useful transportation fuels. PMID:27099975

  14. In Vivo Models to Address the Function of Polycomb Group Proteins.

    PubMed

    Bantignies, Frédéric

    2016-01-01

    Initially discovered as repressors of homeotic gene expression in Drosophila, Polycomb group (PcG) proteins have now been shown to be involved in a plethora of biological processes. Indeed, by repressing a large number of target genes, including specific lineage genes, these chromatin factors play major roles in a multitude of cellular functions, such as pluripotency, differentiation, reprogramming, tissue regeneration, and nuclear organization. In this book chapter are presented in vivo approaches and technologies, which have been used in both mammalian and Drosophila systems to study the cellular functions of Polycomb group proteins. PMID:27659991

  15. Effects of surface functional groups on the formation of nanoparticle-protein corona

    NASA Astrophysics Data System (ADS)

    Podila, R.; Chen, R.; Ke, P. C.; Brown, J. M.; Rao, A. M.

    2012-12-01

    Herein, we examined the dependence of protein adsorption on the nanoparticle surface in the presence of functional groups. Our UV-visible spectrophotometry, transmission electron microscopy, infrared spectroscopy, and dynamic light scattering measurements evidently suggested that the functional groups play an important role in the formation of nanoparticle-protein corona. We found that uncoated and surfactant-free silver nanoparticles derived from a laser ablation process promoted a maximum protein (bovine serum albumin) coating due to increased changes in entropy. On the other hand, bovine serum albumin displayed a relatively lower affinity for electrostatically stabilized nanoparticles due to the constrained entropy changes.

  16. [Responses of ground arthropod functional groups to the enclosure of grazing grassland in desert steppe].

    PubMed

    Liu, Ren-tao; Li, Xue-bin; Xin, Ming; Ma, Lin; Liu, Kai

    2011-08-01

    With the support of the National Resources Monitoring Station in Yanchi County of Ningxia, an investigation was conducted on the ground arthropods, vegetations, and soil properties in the enclosed and un-enclosed grazing grassland in desert steppe. In the meantime, the functional groups of ground arthropods were classified according to their feeding habits. The ground arthropods in the desert steppe could be classified into four functional groups, i.e., predatory, phytophagous, saprophagous, and omnivorous, among which, predatory and phytophagous groups were dominant in quantity, and phytophagous and saprophagous groups were predominant in biomass, implying that the ground arthropod in desert steppe was mainly characterized by phytophagous arthropods. Enclosure increased the individual and group number of predatory, phytophagous, and omnivorous arthropods as well as the biomass of predatory and omnivorous arthropods, and enhanced the biodiversity of predatory and phytophagous arthropods, which was closely correlated with the vegetation recovery and soil environment improvement, and demonstrated that the enclosure of grazing grassland increased the diversity and complexity of ground arthropod functional groups in desert steppe. Nevertheless, the individual number and biomass of saprophagous arthropods decreased after the enclosure, reflecting the dependence of these arthropods on grazing grassland.

  17. Multiconfiguration pair-density functional theory: barrier heights and main group and transition metal energetics.

    PubMed

    Carlson, Rebecca K; Li Manni, Giovanni; Sonnenberger, Andrew L; Truhlar, Donald G; Gagliardi, Laura

    2015-01-13

    Kohn-Sham density functional theory, resting on the representation of the electronic density and kinetic energy by a single Slater determinant, has revolutionized chemistry, but for open-shell systems, the Kohn-Sham Slater determinant has the wrong symmetry properties as compared to an accurate wave function. We have recently proposed a theory, called multiconfiguration pair-density functional theory (MC-PDFT), in which the electronic kinetic energy and classical Coulomb energy are calculated from a multiconfiguration wave function with the correct symmetry properties, and the rest of the energy is calculated from a density functional, called the on-top density functional, that depends on the density and the on-top pair density calculated from this wave function. We also proposed a simple way to approximate the on-top density functional by translation of Kohn-Sham exchange-correlation functionals. The method is much less expensive than other post-SCF methods for calculating the dynamical correlation energy starting with a multiconfiguration self-consistent-field wave function as the reference wave function, and initial tests of the theory were quite encouraging. Here, we provide a broader test of the theory by applying it to bond energies of main-group molecules and transition metal complexes, barrier heights and reaction energies for diverse chemical reactions, proton affinities, and the water dimerization energy. Averaged over 56 data points, the mean unsigned error is 3.2 kcal/mol for MC-PDFT, as compared to 6.9 kcal/mol for Kohn-Sham theory with a comparable density functional. MC-PDFT is more accurate on average than complete active space second-order perturbation theory (CASPT2) for main-group small-molecule bond energies, alkyl bond dissociation energies, transition-metal-ligand bond energies, proton affinities, and the water dimerization energy.

  18. Effect of Duration of Disease on Ventilatory Function in an Ethnic Saudi Group of Diabetic Patients

    PubMed Central

    Meo, Sultan A.; Al Drees, Abdul Majeed; Ahmed, Jehangeer; Ahmed Shah, Sayed Fayaz; Al-Regaiey, Khalid; Husain, Ashraf; Al-Rubean, Khalid

    2007-01-01

    Background Diabetes mellitus is a leading cause of illness and death across the world and is responsible for a growing proportion of global health care expenditures. The present study was designed to observe the effect of diabetes mellitus on lung function in patients with diabetes belonging to a specific ethnic group, namely Saudis. Method In this study, a group of 47 apparently healthy volunteer male Saudi patients with diabetes was randomly selected. Their ages ranged from 20 to 70 years. The patients were matched with another group of 50 healthy male control subjects in terms of age, height, weight, ethnicity, and socioeconomic status. Both groups met exclusion criteria as per standard. Spirometry was performed with an electronic spirometer (Schiller AT-2 Plus, Switzerland), and results were compared by a Student's t test. Results Subjects with diabetes showed a significant reduction in forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1) relative to their matched controls. However, there were no significant differences in the forced expiratory ratio (FEV1/FVC%) and the middle half of the FVC (FEF25–75%) between the groups. We observed a significantly negative correlation between duration of disease and pulmonary function, as measured by FEV1 (r = 0.258, p = 0.04), FVC (r = 0.282, p = 0.28), and the middle half of the FVC (FEF25–75%) (r = 0.321, p = 0.014). Conclusions Pulmonary function in a specific ethnic group of patients with diabetes was impaired as evidenced by a decrease in FVC and FEV1 compared to pulmonary function in matched controls. Stratification of results by years of disease revealed a significant correlation between duration of disease and a decline in pulmonary function. PMID:19885139

  19. Isolation and Characterization of Functional Tripartite Group II Introns Using a Tn5-Based Genetic Screen

    PubMed Central

    Ritlop, Christine; Monat, Caroline; Cousineau, Benoit

    2012-01-01

    Background Group II introns are RNA enzymes that splice themselves from pre-mRNA transcripts. Most bacterial group II introns harbour an open reading frame (ORF), coding for a protein with reverse transcriptase, maturase and occasionally DNA binding and endonuclease activities. Some ORF-containing group II introns were shown to be mobile retroelements that invade new DNA target sites. From an evolutionary perspective, group II introns are hypothesized to be the ancestors of the spliceosome-dependent nuclear introns and the small nuclear RNAs (snRNAs – U1, U2, U4, U5 and U6) that are important functional elements of the spliceosome machinery. The ability of some group II introns fragmented in two or three pieces to assemble and undergo splicing in trans supports the theory that spliceosomal snRNAs evolved from portions of group II introns. Methodology/Principal Findings We used a transposon-based genetic screen to explore the ability of the Ll.LtrB group II intron from the Gram-positive bacterium Lactococcus lactis to be fragmented into three pieces in vivo. Trans-splicing tripartite variants of Ll.LtrB were selected using a highly efficient and sensitive trans-splicing/conjugation screen. We report that numerous fragmentation sites located throughout Ll.LtrB support tripartite trans-splicing, showing that this intron is remarkably tolerant to fragmentation. Conclusions/Significance This work unveils the great versatility of group II intron fragments to assemble and accurately trans-splice their flanking exons in vivo. The selected introns represent the first evidence of functional tripartite group II introns in bacteria and provide experimental support for the proposed evolutionary relationship between group II introns and snRNAs. PMID:22876289

  20. Attachment theory and group processes: the association between attachment style and group-related representations, goals, memories, and functioning.

    PubMed

    Rom, Eldad; Mikulincer, Mario

    2003-06-01

    Four studies examined attachment-style differences in group-related cognitions and behaviors. In Studies 1-2, participants completed scales on group-related cognitions and emotions. In Studies 3-4, participants were divided into small groups, and their performance in group tasks as well as the cohesion of their group were assessed. Both attachment anxiety and avoidance in close relationships were associated with negative group-related cognitions and emotions. Anxiety was also related to the pursuit of closeness goals and impaired instrumental performance in group tasks. Avoidance was related to the pursuit of distance goals and deficits in socioemotional and instrumental performance. Group cohesion significantly moderated the effects of attachment anxiety. The discussion emphasizes the relevance of attachment theory within group contexts. PMID:12793586

  1. Attachment theory and group processes: the association between attachment style and group-related representations, goals, memories, and functioning.

    PubMed

    Rom, Eldad; Mikulincer, Mario

    2003-06-01

    Four studies examined attachment-style differences in group-related cognitions and behaviors. In Studies 1-2, participants completed scales on group-related cognitions and emotions. In Studies 3-4, participants were divided into small groups, and their performance in group tasks as well as the cohesion of their group were assessed. Both attachment anxiety and avoidance in close relationships were associated with negative group-related cognitions and emotions. Anxiety was also related to the pursuit of closeness goals and impaired instrumental performance in group tasks. Avoidance was related to the pursuit of distance goals and deficits in socioemotional and instrumental performance. Group cohesion significantly moderated the effects of attachment anxiety. The discussion emphasizes the relevance of attachment theory within group contexts.

  2. 14 CFR 10 - Functional Classification-Operating Expenses of Group I Air Carriers

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Functional Classification-Operating Expenses of Group I Air Carriers Section 10 Section Section 10 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED AIR...

  3. Review of Social Skills Training Groups for Youth with Asperger Syndrome and High Functioning Autism

    ERIC Educational Resources Information Center

    Cappadocia, M. Catherine; Weiss, Jonathan A.

    2011-01-01

    Although social skills deficits represent core symptoms of Asperger Syndrome and High Functioning Autism, there is limited research investigating the empirical validity of social skills interventions currently being used with these populations. This literature review compares three types of social skills training groups: traditional, cognitive…

  4. Attraction to a Group as a Function of Attitude Similarity and Geographic Distance.

    ERIC Educational Resources Information Center

    Davis, John M.

    1984-01-01

    Investigated attraction toward a group as a function of attitude similarity and perceived geographic distance in students (N=60). Results showed that effects of attitude similarity were strongly significant and that distance had no signficant effect on attraction and limited effect on evaluations. (LLL)

  5. An Epistemological Inquiry into Organic Chemistry Education: Exploration of Undergraduate Students' Conceptual Understanding of Functional Groups

    ERIC Educational Resources Information Center

    Akkuzu, Nalan; Uyulgan, Melis Arzu

    2016-01-01

    This study sought to determine the levels of conceptual understanding of undergraduate students regarding organic compounds within different functional groups. A total of 60 students who were enrolled in the Department of Secondary Science and Mathematics Education of a Faculty of Education at a state university in Turkey and who had followed an…

  6. A FUNCTIONAL GROUP CHARACTERIZATION OF ORGANIC PM 2.5 EXPOSURE: RESULTS FROM THE RIOPA STUDY

    EPA Science Inventory

    The functional group (FG) composition of urban residential outdoor, indoor, and personal fine particle (PM2.5) samples is presented and used to provide insights relevant to organic PM2.5 exposure. PM2.5 samples (48 h) were collected during the Rel...

  7. Social Resources and Change in Functional Health: Comparing Three Age Groups

    ERIC Educational Resources Information Center

    Randall, G. Kevin; Martin, Peter; Bishop, Alex J.; Johnson, Mary Ann; Poon, Leonard W.

    2012-01-01

    This study examined the mediating and moderating role of social resources on the association between age and change in functional health for three age groups of older adults. Data were provided by those in their 60s, 80s, and 100s who participated in the first two phases of the Georgia Centenarian study. Analyses confirmed the study's hypothesis…

  8. Chemkarta: A Card Game for Teaching Functional Groups in Undergraduate Organic Chemistry

    ERIC Educational Resources Information Center

    Knudtson, Christopher A.

    2015-01-01

    Students in undergraduate organic chemistry courses are frequently overwhelmed by the volume and complexity of information they are expected to learn. To aid in students' learning of organic functional groups, a novel card game "ChemKarta" is reported that can serve as a useful alternative to flashcards. This pedagogy is a simple…

  9. Detecting Native Language Group Differences at the Subskills Level of Reading: A Differential Skill Functioning Approach

    ERIC Educational Resources Information Center

    Li, Hongli; Suen, Hoi K.

    2013-01-01

    Differential skill functioning (DSF) exists when examinees from different groups have different probabilities of successful performance in a certain subskill underlying the measured construct, given that they have the same ability on the overall construct. Using a DSF approach, this study examined the differences between two native language…

  10. Urinary Cortisol Circadian Rhythm in a Group of High-Functioning Children with Autism.

    ERIC Educational Resources Information Center

    Richdale, Amanda L.; Prior, Margot R.

    1992-01-01

    This study found no evidence for abnormal temporal placement of the basal urinary cortisol circadian rhythm in a group of 18 high-functioning children (ages 4-14) with autism. There was a tendency toward cortisol hypersecretion during the day, predominantly in autistic children who were integrated into the normal school system. (Author/JDD)

  11. Group-Specific Effects of Matching Subtest Contamination on the Identification of Differential Item Functioning

    ERIC Educational Resources Information Center

    Keiffer, Elizabeth Ann

    2011-01-01

    A differential item functioning (DIF) simulation study was conducted to explore the type and level of impact that contamination had on type I error and power rates in DIF analyses when the suspect item favored the same or opposite group as the DIF items in the matching subtest. Type I error and power rates were displayed separately for the…

  12. Magnetic iron oxide nanoparticle functionalization: isocyanate moiety as a suitable monodentate anchoring group.

    PubMed

    Carrara, Claudio; Sala, Maria C; Caneva, Enrico; Cauteruccio, Silvia; Licandro, Emanuela

    2014-01-17

    A new strategy for anchoring organic molecules onto superparamagnetic iron oxide nanoparticles (SPIONs) using isocyanate containing linkers has been realized. This functional group easily and efficiently reacts with the hydroxyl residues of the nanoparticle surface, leading to the formation of a stable carbamate bond, as confirmed by means of spectroscopic and analytical data.

  13. Youth in group home care: youth characteristics and predictors of later functioning.

    PubMed

    Chow, Wai-Ying; Mettrick, Jennifer E; Stephan, Sharon H; Von Waldner, Christina A

    2014-10-01

    This paper presents the findings of an exploratory research study of foster care youth residing in group homes in a mid-Atlantic state in the USA. The aims of the present study were to (1) describe youth characteristics, (2) explore whether baseline functioning differed by gender or ethnicity, (3) explore predictors of cross-time differences in psychosocial functioning, and (4) explore predictors of later functioning, specifically age, gender, and length of stay. Psychosocial functioning at two time points (i.e., T1 = admission into group home; T2 = current or discharge) in 180 charts from 29 randomly selected group homes were reviewed. Youth were on average 14.86 years of age, predominantly male (71%; n = 128), and predominantly African American (79%). Findings suggest that group home placement may benefit some youth but not others, particularly girls and younger children with lower initial level of need. Findings underscore the potential complexity of intervention impact in the context of unique youth, family, and environment factors. PMID:22529035

  14. Class-Wide Function-Related Intervention Teams: Effects of Group Contingency Programs in Urban Classrooms

    ERIC Educational Resources Information Center

    Kamps, Debra; Wills, Howard P.; Heitzman-Powell, Linda; Laylin, Jeff; Szoke, Carolyn; Petrillo, Tai; Culey, Amy

    2011-01-01

    The purpose of the study was to determine the effectiveness of the Class-Wide Function-related Intervention Teams (CW-FIT) program, a group contingency intervention for whole classes, and for students with disruptive behaviors who are at risk for emotional/behavioral disorders (EBD). The CW-FIT program includes four elements designed from…

  15. Neuropsychological Functioning in Specific Learning Disorders--Reading, Writing and Mixed Groups

    ERIC Educational Resources Information Center

    Kohli, Adarsh; Kaur, Manreet; Mohanty, Manju; Malhotra, Savita

    2006-01-01

    Aim: The study compared the pattern of deficits, intelligence and neuropsychological functioning in subcategories of learning disorders. Methods: Forty-six children (16 with reading disorders, 11 with writing disorders and 19 with both reading and writing disorders--mixed group) in the age range of 7-14 years were assessed using the NIMHANS Index…

  16. Minerals and functional groups present in the jackfruit seed: a spectroscopic investigation.

    PubMed

    Barua, A Gohain; Boruah, B R

    2004-09-01

    In this work, emission and Fourier transform infrared spectra of the jackfruit seed, in powdered form, are recorded. Analysis of the emission spectrum confirms the presence of two hitherto undetected elements, manganese and magnesium. The Fourier transform infrared spectrum reveals the presence of some specific functional groups, attributed to the different bands present in the spectrum.

  17. IMPORTANCE OF ACTIVATED CARBON'S OXYGEN SURFACE FUNCTIONAL GROUPS ON ELEMENTAL MERCURY ADSORPTION

    EPA Science Inventory

    The effect of varying physical and chemical properties of activated carbons on adsorption of elemental mercury [Hg(0)] was studied by treating two activated carbons to modify their surface functional groups and pore structures. Heat treatment (1200 K) in nitrogen (N2), air oxidat...

  18. Functional group analysis in coal and on coal surfaces by NMR spectroscopy

    SciTech Connect

    Verkade, J.G.

    1990-01-01

    An accurate knowledge of the oxygen-bearing labile hydrogen functional groups (e.g., carboxylic acids, phenols and alcohols) in coal is required for today's increasingly sophisticated coal cleaning and beneficiation processes. Phospholanes (compounds having the general structure -POCH{sub 2}CH{sub 2}O (1)) are being investigated as reagents for the tagging of liable hydrogen functional groups in coal materials with the NMR-active {sup 31}P nucleus. Of twelve such reagents investigated so far, 2 (2-chloro-1,3-dioxaphospholane, ClPOCH{sub 2}CH{sub 2}O) and 8 (2-chloro-1,3-dithiaphospholane, ClPSCH{sub 2}CH{sub 2}S) have been found to be useful in identifying and quantitating, by {sup 31}P NMR spectroscopy, labile hydrogen functional groups in an Illinois No. 6 coal condensate. Reagent 2 has also been used to quantitate moisture in pyridine extracts of Argonne Premium Coal Samples. Preliminary {sup 119}Sn NMR spectroscopic results on model compounds with the new reagent CF{sub 3}C(O)NHSnMe{sub 3} (N-trimethylstannyltrifluoroacetamide, 14) suggest that labile hydrogen functional groups in coal materials may be more precisely identified with 14 than with phospholanes. 14 refs., 2 figs., 2 tabs.

  19. Organic functional group transformations in water at elevated temperature and pressure: Reversibility, reactivity, and mechanisms

    NASA Astrophysics Data System (ADS)

    Shipp, Jessie; Gould, Ian R.; Herckes, Pierre; Shock, Everett L.; Williams, Lynda B.; Hartnett, Hilairy E.

    2013-03-01

    Many transformation reactions involving hydrocarbons occur in the presence of H2O in hydrothermal systems and deep sedimentary systems. We investigate these reactions using laboratory-based organic chemistry experiments at high temperature and pressure (300 °C and 100 MPa). Organic functional group transformation reactions using model organic compounds based on cyclohexane with one or two methyl groups provided regio- and stereochemical markers that yield information about reversibility and reaction mechanisms. We found rapidly reversible interconversion between alkanes, alkenes, dienes, alcohols, ketones, and enones. The alkane-to-ketone reactions were not only completely reversible, but also exhibited such extensive reversibility that any of the functional groups along the reaction path (alcohol, ketone, and even the diene) could be used as the reactant and form all the other groups as products. There was also a propensity for these ring-based structures to dehydrogenate; presumably from the alkene, through a diene, to an aromatic ring. The product suites provide strong evidence that water behaved as a reactant and the various functional groups showed differing degrees of reactivity. Mechanistically-revealing products indicated reaction mechanisms that involve carbon-centered cation intermediates. This work therefore demonstrates that a wide range of organic compound types can be generated by abiotic reactions at hydrothermal conditions.

  20. A meta-analysis of functional group responses to forest recovery outside of the tropics.

    PubMed

    Spake, Rebecca; Ezard, Thomas H G; Martin, Philip A; Newton, Adrian C; Doncaster, C Patrick

    2015-12-01

    Both active and passive forest restoration schemes are used in degraded landscapes across the world to enhance biodiversity and ecosystem service provision. Restoration is increasingly also being implemented in biodiversity offset schemes as compensation for loss of natural habitat to anthropogenic development. This has raised concerns about the value of replacing old-growth forest with plantations, motivating research on biodiversity recovery as forest stands age. Functional diversity is now advocated as a key metric for restoration success, yet it has received little analytical attention to date. We conducted a meta-analysis of 90 studies that measured differences in species richness for functional groups of fungi, lichens, and beetles between old-growth control and planted or secondary treatment forests in temperate, boreal, and Mediterranean regions. We identified functional-group-specific relationships in the response of species richness to stand age after forest disturbance. Ectomycorrhizal fungi averaged 90 years for recovery to old-growth values (between 45 years and unrecoverable at 95% prediction limits), and epiphytic lichens took 180 years to reach 90% of old-growth values (between 140 years and never for recovery to old-growth values at 95% prediction limits). Non-saproxylic beetle richness, in contrast, decreased as stand age of broadleaved forests increased. The slow recovery by some functional groups essential to ecosystem functioning makes old-growth forest an effectively irreplaceable biodiversity resource that should be exempt from biodiversity offsetting initiatives. PMID:26040756

  1. A meta-analysis of functional group responses to forest recovery outside of the tropics.

    PubMed

    Spake, Rebecca; Ezard, Thomas H G; Martin, Philip A; Newton, Adrian C; Doncaster, C Patrick

    2015-12-01

    Both active and passive forest restoration schemes are used in degraded landscapes across the world to enhance biodiversity and ecosystem service provision. Restoration is increasingly also being implemented in biodiversity offset schemes as compensation for loss of natural habitat to anthropogenic development. This has raised concerns about the value of replacing old-growth forest with plantations, motivating research on biodiversity recovery as forest stands age. Functional diversity is now advocated as a key metric for restoration success, yet it has received little analytical attention to date. We conducted a meta-analysis of 90 studies that measured differences in species richness for functional groups of fungi, lichens, and beetles between old-growth control and planted or secondary treatment forests in temperate, boreal, and Mediterranean regions. We identified functional-group-specific relationships in the response of species richness to stand age after forest disturbance. Ectomycorrhizal fungi averaged 90 years for recovery to old-growth values (between 45 years and unrecoverable at 95% prediction limits), and epiphytic lichens took 180 years to reach 90% of old-growth values (between 140 years and never for recovery to old-growth values at 95% prediction limits). Non-saproxylic beetle richness, in contrast, decreased as stand age of broadleaved forests increased. The slow recovery by some functional groups essential to ecosystem functioning makes old-growth forest an effectively irreplaceable biodiversity resource that should be exempt from biodiversity offsetting initiatives.

  2. Effect of Habitat Size, Quality, and Isolation on Functional Groups of Beetles in Hollow Oaks

    PubMed Central

    Pilskog, Hanne Eik; Birkemoe, Tone; Framstad, Erik; Sverdrup-Thygeson, Anne

    2016-01-01

    One of the largest threats to biodiversity is land use change and habitat loss. Hollow oaks (Quercus spp. L.) are well-defined patches that are hotspots for biodiversity and red-listed species, but they are often rare and fragmented in the landscape. We investigated the effect of patch size, habitat quality, and isolation on functional groups and red-listed saproxylic beetles in hollow oaks (n = 40) in Norway. The groups were defined by host tree association, trophic grouping, and red-listed status. Habitat quality, represented by tree form was most important in explaining species richness for most groups. Patch size, represented by circumference and amount of dead branches, was most important in explaining abundance. Isolation, that is single oaks compared with oaks in groups, had a negative effect on the abundance of beetles feeding both on wood and fungi (xylomycethopagous), as well as on species associated with broadleaved trees (oak semi-specialists), but did not affect species richness. This indicates that at this scale and in this landscape, isolated oaks are as species rich and valuable for conservation as other oaks, although some functional groups may be more vulnerable to isolation than others. The red-listed species only responded to patch size, indicating that oaks with large circumference and many dead branches are especially important for red-listed species and for conservation. PMID:26945089

  3. Effect of Habitat Size, Quality, and Isolation on Functional Groups of Beetles in Hollow Oaks.

    PubMed

    Pilskog, Hanne Eik; Birkemoe, Tone; Framstad, Erik; Sverdrup-Thygeson, Anne

    2016-01-01

    One of the largest threats to biodiversity is land use change and habitat loss. Hollow oaks (Quercus spp. L.) are well-defined patches that are hotspots for biodiversity and red-listed species, but they are often rare and fragmented in the landscape. We investigated the effect of patch size, habitat quality, and isolation on functional groups and red-listed saproxylic beetles in hollow oaks (n = 40) in Norway. The groups were defined by host tree association, trophic grouping, and red-listed status. Habitat quality, represented by tree form was most important in explaining species richness for most groups. Patch size, represented by circumference and amount of dead branches, was most important in explaining abundance. Isolation, that is single oaks compared with oaks in groups, had a negative effect on the abundance of beetles feeding both on wood and fungi (xylomycethopagous), as well as on species associated with broadleaved trees (oak semi-specialists), but did not affect species richness. This indicates that at this scale and in this landscape, isolated oaks are as species rich and valuable for conservation as other oaks, although some functional groups may be more vulnerable to isolation than others. The red-listed species only responded to patch size, indicating that oaks with large circumference and many dead branches are especially important for red-listed species and for conservation. PMID:26945089

  4. Development of Acid Functional Groups and Lactones During the Thermal Degradation of Wood and Wood Components

    USGS Publications Warehouse

    Rutherford, David W.; Wershaw, Robert L.; Reeves, James B.

    2008-01-01

    Black carbon (pyrogenic materials including chars) in soils has been recognized as a substantial portion of soil organic matter, and has been shown to play a vital role in nutrient cycling; however, little is known concerning the properties of this material. Previous studies have largely been concerned with the creation of high-surface-area materials for use as sorbents. These materials have been manufactured at high temperature and have often been activated. Chars occurring in the environment can be formed over a wide range of temperature. Because it is extremely difficult to isolate black carbon once it has been incorporated in soils, chars produced in the laboratory under controlled conditions can be used to investigate the range of properties possible for natural chars. This report shows that charring conditions (temperature and time) have substantial impact on the acid functional group and lactone content of chars. Low temperatures (250?C) and long charring times (greater than 72 hours) produce chars with the highest acid functional group and lactone content. The charring of cellulose appears to be responsible for the creation of the acid functional group and lactones. The significance of this study is that low-temperature chars can have acid functional group contents comparable to humic materials (as high as 8.8 milliequivalents per gram). Acid functional group and lactone content decreases as charring temperature increases. The variation in formation conditions expected under natural fire conditions will result in a wide range of sorption properties for natural chars which are an important component of soil organic matter. By controlling the temperature and duration of charring, it is possible to tailor the sorption properties of chars, which may be used as soil amendments.

  5. Advances in the development of catalytic tethering directing groups for C-H functionalization reactions.

    PubMed

    Sun, Huan; Guimond, Nicolas; Huang, Yong

    2016-09-28

    Transition metal-catalyzed C-H bond insertion is one of the most straightforward strategies to introduce functionalities within a hydrocarbon microenvironment. For the past two decades, selective activation and functionalization of certain inert C-H bonds have been made possible with the help of directing groups (DGs). Despite the enormous advances in the field, an overwhelming majority of systems require two extra steps from their simple precursors: installation and removal of the DGs. Recently, traceless and multitasking groups were invented as a partial solution to DG release. However, installation remains largely unsolved. Ideally, a transient, catalytic DG would circumvent this problem and increase the step- and atom-economy of C-H functionalization processes. In this review, we summarize the recent development of the transient tethering strategy for C-H activation reactions. PMID:27506568

  6. Selective functionalization of hollow nanospheres with Acid and base groups for cascade reactions.

    PubMed

    Gao, Jinsuo; Zhang, Xueying; Lu, Yong; Liu, Shaomin; Liu, Jian

    2015-05-11

    The inner-surface functionalization of hollow silica spheres has rarely been reported and is still a challenging topic. Herein, we report a deacetalization-Henry cascade reaction catalyzed by dual-functionalized mesoporous silica hollow nanospheres with basic amine groups (NH2 ) on the internal shell and carboxylic acid groups (COOH) on the external shell. The selective functionalization has been realized by a combination of "step-by-step post-grafting" and "cationic surfactant-assisted selective etching" strategy. Compared to unisolated catalyst, the selectively isolated acidic and basic dual catalyst provides excellent catalytic performance for the deacetalization-Henry cascade reaction in terms of both activity (>99 %) and selectivity (95 %).

  7. Wetting properties of model interphases coated with defined organic functional groups

    NASA Astrophysics Data System (ADS)

    Woche, Susanne K.; Goebel, Marc-O.; Guggenberger, Georg; Tunega, Daniel; Bachmann, Joerg

    2013-04-01

    Surface properties of soil particles are of particular interest regarding transport of water and sorption of solutes, especially hazardous xenobiotic species. Wetting properties (e.g. determined by contact angle, CA), governed by the functional groups exposed, are crucial to understand sorption processes in water repellent soils as well as for the geometry of water films sustaining microbial processes on the pore scale. Natural soil particle surfaces are characterized by a wide variety of mineralogical and chemical compounds. Their composition is almost impossible to identify in full. Hence, in order to get a better understanding about surface properties, an option is the usage of defined model surfaces, whereas the created surface should be comparable to natural soil interphases. We exposed smooth glass surfaces to different silane compounds, resulting in a coating covalently bound to the surface and exhibiting defined organic functional groups towards the pore space. The wetting properties as evaluated by CA and the surface free energy (SFE), calculated according to the Acid-Base Theory, were found to be a function of the specific functional group. Specifically, the treated surfaces showed a large variation of CA and SFE as function of chain length and polarity of the organic functional group. The study of wetting properties was accompanied by XPS analysis for selective detection of chemical compounds of the interphase. As the reaction mechanism of the coating process is known, the resulting interphase structure can be modeled based on energetic considerations. A next step is to use same coatings for the defined modification of the pore surfaces of porous media to study transport and sorption processes in complex three phase systems.

  8. Zooplankton functional groups on the continental shelf of the yellow sea

    NASA Astrophysics Data System (ADS)

    Sun, Song; Huo, Yuanzi; Yang, Bo

    2010-06-01

    Zooplankton plays a vital role in marine ecosystems. Variations in the zooplankton species composition, biomass, and secondary production will change the structure and function of the ecosystem. How to describe this process and make it easier to be modeled in the Yellow Sea ecosystem is the main purpose of this paper. The zooplankton functional groups approach, which is considered a good method of linking the structure of food webs and the energy flow in the ecosystems, is used to describe the main contributors of secondary produciton of the Yellow Sea ecosystem. The zooplankton can be classified into six functional groups: giant crustaceans, large copepods, small copepods, chaetognaths, medusae, and salps. The giant crustaceans, large copepods, and small copepods groups, which are the main food resources for fish, are defined depending on the size spectrum. Medusae and chaetognaths are the two gelatinous carnivorous groups, which compete with fish for food. The salps group, acting as passive filter-feeders, competes with other species feeding on phytoplankton, but their energy could not be efficiently transferred to higher trophic levels. From the viewpoint of biomass, which is the basis of the food web, and feeding activities, the contributions of each functional group to the ecosystem were evaluated; the seasonal variations, geographical distribution patterns, and species composition of each functional group were analyzed. The average zooplankton biomass was 2.1 g dry wt m -2 in spring, to which the giant crustaceans, large copepods, and small copepods contributed 19, 44, and 26%, respectively. High biomasses of the large copepods and small copepods were distributed at the coastal waters, while the giant crustaceans were mainly located at offshore area. In summer, the mean biomass was 3.1 g dry wt m -2, which was mostly contributed by the giant crustaceans (73%), and high biomasses of the giant crustaceans, large copepods, and small copepods were all distributed

  9. Functionalization of carbon nanotubes with -CH(n), -NH(n) fragments, -COOH and -OH groups.

    PubMed

    Milowska, Karolina Z; Majewski, Jacek A

    2013-05-21

    We present results of extensive theoretical studies concerning stability, morphology, and band structure of single wall carbon nanotubes (CNTs) covalently functionalized by -CH(n) (for n = 2,3,4), -NH(n) (for n = 1,2,3,4), -COOH, and -OH groups. These studies are based on ab initio calculations in the framework of the density functional theory. For functionalized systems, we determine the dependence of the binding energies on the concentration of the adsorbed molecules, critical densities of adsorbed molecules, global and local changes in the morphology, and electronic structure paying particular attention to the functionalization induced changes of the band gaps. These studies reveal physical mechanisms that determine stability and electronic structure of functionalized systems and also provide valuable theoretical predictions relevant for application. In particular, we observe that functionalization of CNTs causes generally their elongation and locally sp(2) to sp(3) rehybridization in the neighborhood of chemisorbed molecules. For adsorbants making particularly strong covalent bonds with the CNTs, such as the -CH2 fragments, we observe formation of the characteristic pentagon/heptagon (5/7) defects. In systems functionalized with the -CH2, -NH4, and -OH groups, we determine critical density of molecules that could be covalently bound to the lateral surface of CNTs. Our studies show that functionalization of CNTs can be utilized for band gap engineering. Functionalization of CNTs can also lead to changes in their metallic/semiconductor character. In semiconducting CNTs, functionalizing molecules such as -CH3, -NH2, -OH, -COOH, and both -OH and -COOH, introduce "impurity" bands in the band gap of pristine CNTs. In the case of -CH3, -NH2 molecules, the induced band gaps are typically smaller than in the pure CNT and depend strongly on the concentration of adsorbants. However, functionalization of semiconducting CNTs with hydroxyl groups leads to the metallization

  10. Tumor-suppressor effects of chemical functional groups in an in vitro co-culture system

    NASA Astrophysics Data System (ADS)

    Xu, Su-Ju; Cui, Fu-Zhai; Kong, Xiang-Dong

    2014-06-01

    Liver normal cells and cancer cells co-cultured on surfaces modified by different chemical functional groups, including mercapto (-SH), hydroxyl (-OH) and methyl (-CH3) groups. The results showed that different cells exhibited changes in response to different surfaces. Normal cells on -SH surface exhibited the smallest contact area with mostly rounded morphology, which led to the death of cancer cells, while cancer cells could not grow on -CH3 groups, which also died. In the co-culture system, the -CH3 group exhibited its unique effect that could trigger the death of cancer cells and had no effects on normal cells. Our findings provide useful information on strategies for the design of efficient and safe regenerative medicine materials.

  11. Kelvin-probe force microscopy of the pH-dependent charge of functional groups

    NASA Astrophysics Data System (ADS)

    Stone, Alexander D. D.; Mesquida, Patrick

    2016-06-01

    Kelvin-probe Force Microscopy (KFM) is an established method to map surface potentials or surface charges at high, spatial resolution. However, KFM does not work in water, which restricts its applicability considerably, especially when considering common, functional chemical groups in biophysics such as amine or carboxy groups, whose charge depends on pH. Here, we demonstrate that the KFM signal of such groups taken in air after exposure to water correlates qualitatively with their expected charge in water for a wide range of pH values. The correlation was tested with microcontact-printed thiols exposing amine and carboxy groups. Furthermore, it was shown that collagen fibrils, as an example of a biological material, exhibit a particular, pH-sensitive surface charge pattern, which could be caused by the particular arrangement of ionizable residues on the collagen fibril surface.

  12. Hydrogen-bond acidic functionalized carbon nanotubes (CNTs) with covalently-bound hexafluoroisopropanol groups

    SciTech Connect

    Fifield, Leonard S.; Grate, Jay W.

    2010-06-01

    Fluorinated hydrogen-bond acidic groups are directly attached to the backbone of single walled carbon nanotubes (SWCNTs) without the introduction of intermediate electron donating surface groups. Hexafluoroalcohol functional groups are exceptionally strong hydrogen bond acids, and are added to the nanotube surface using the aryl diazonium approach to create hydrogen-bond acidic carbon nanotube (CNT) surfaces. These groups can promote strong hydrogen-bonding interactions with matrix materials in composites or with molecular species to be concentrated and sensed. In the latter case, this newly developed material is expected to find useful application in chemical sensors and in CNT-based preconcentrator devices for the detection of pesticides, chemical warfare agents and explosives.

  13. Matrix intensification alters avian functional group composition in adjacent rainforest fragments.

    PubMed

    Deikumah, Justus P; McAlpine, Clive A; Maron, Martine

    2013-01-01

    Conversion of farmland land-use matrices to surface mining is an increasing threat to the habitat quality of forest remnants and their constituent biota, with consequences for ecosystem functionality. We evaluated the effects of matrix type on bird community composition and the abundance and evenness within avian functional groups in south-west Ghana. We hypothesized that surface mining near remnants may result in a shift in functional composition of avifaunal communities, potentially disrupting ecological processes within tropical forest ecosystems. Matrix intensification and proximity to the remnant edge strongly influenced the abundance of members of several functional guilds. Obligate frugivores, strict terrestrial insectivores, lower and upper strata birds, and insect gleaners were most negatively affected by adjacent mining matrices, suggesting certain ecosystem processes such as seed dispersal may be disrupted by landscape change in this region. Evenness of these functional guilds was also lower in remnants adjacent to surface mining, regardless of the distance from remnant edge, with the exception of strict terrestrial insectivores. These shifts suggest matrix intensification can influence avian functional group composition and related ecosystem-level processes in adjacent forest remnants. The management of matrix habitat quality near and within mine concessions is important for improving efforts to preserveavian biodiversity in landscapes undergoing intensification such as through increased surface mining. PMID:24058634

  14. Effects of Trehalose Polycation End-group Functionalization on Plasmid DNA Uptake and Transfection

    PubMed Central

    Anderson, Kevin; Sizovs, Antons; Cortez, Mallory; Waldron, Chris; Haddleton, D.M.; Reineke, Theresa M.

    2012-01-01

    In this study, we have synthesized six analogs of a trehalose-pentaethylenehexamine glycopolymer (Tr4) that contain (1A) adamantane, (1B) carboxy, (1C) alkynyl-oligoethyleneamine, (1D) azido trehalose, (1E) octyl, or (1F) oligoethyleneamine end groups and evaluated the effects of polymer end group chemistry on the ability of these systems to bind, compact, and deliver pDNA in cultured HeLa cells. The polymers were synthesized in one-pot azide-alkyne cycloaddition reactions with an adaptation of the Carothers equation for step-growth polymerization to produce a series of polymers with similar degrees of polymerization. An excess of end-capping monomer was added at the end of the polymerizations to maximize functionalization efficiency, which was evaluated with GPC, NMR and MALDI-TOF. The polymers were all found to bind and compact pDNA at similarly low N/P ratios and form polyplexes with plasmid DNA. The effects of the different end group structures were most evident in the polyplex internalization and transfection assays completed in the presence of serum, as determined by flow cytometry and luciferase gene expression respectively. The Tr4 polymers end-capped with carboxyl groups (1B) (N/P = 7), octyne (1E) (N/P = 7), and oligoethyleneamine (1F) (N/P = 7), were taken into cells as polyplex and exhibited the highest levels of fluorescence, resulting from labeled reporter plasmid. Similarly, the polymers end-functionalized with the carboxyl groups (1E at N/P = 7), octyl groups (1E at N/P = 15) and, in particular, the oligoethyleneamine groups (F at N/P = 15) yielded dramatically higher reporter gene expression in the presence of serum. This study yields insight into how very subtle structural changes in the polymer chemistry such as end groups can yield very significant differences in the biological delivery efficiency and transgene expression of polymers used for pDNA delivery. PMID:22616977

  15. Effects of trehalose polycation end-group functionalization on plasmid DNA uptake and transfection.

    PubMed

    Anderson, Kevin; Sizovs, Antons; Cortez, Mallory; Waldron, Chris; Haddleton, D M; Reineke, Theresa M

    2012-08-13

    In this study, we have synthesized six analogs of a trehalose-pentaethylenehexamine glycopolymer (Tr4) that contain (1A) adamantane, (1B) carboxy, (1C) alkynyl-oligoethyleneamine, (1D) azido trehalose, (1E) octyl, or (1F) oligoethyleneamine end groups and evaluated the effects of polymer end group chemistry on the ability of these systems to bind, compact, and deliver pDNA to cultured HeLa cells. The polymers were synthesized in one-pot azide-alkyne cycloaddition reactions with an adaptation of the Carothers equation for step-growth polymerization to produce a series of polymers with similar degrees of polymerization. An excess of end-capping monomer was added at the end of the polymerizations to maximize functionalization efficiency, which was evaluated with GPC, NMR, and MALDI-TOF. The polymers were all found to bind and compact pDNA at similarly low N/P ratios and form polyplexes with plasmid DNA. The effects of the different end group structures were most evident in the polyplex internalization and transfection assays in the presence of serum as determined by flow cytometry and luciferase gene expression, respectively. The Tr4 polymers end-capped with carboxyl groups (1B) (N/P = 7), octyne (1E) (N/P = 7), and oligoethyleneamine (1F) (N/P = 7), were taken into cells as polyplex and exhibited the highest levels of fluorescence, resulting from labeled plasmid. Similarly, the polymers end-functionalized with carboxyl groups (1E at N/P = 7), octyl groups (1E at N/P = 15), and in particular oligoethyleneamine groups (1F at N/P = 15) yielded dramatically higher reporter gene expression in the presence of serum. This study yields insight into how very subtle structural changes in polymer chemistry, such as end groups can yield very significant differences in the biological delivery efficiency and transgene expression of polymers used for pDNA delivery.

  16. Refinements to the structure of graphite oxide: absolute quantification of functional groups via selective labelling

    NASA Astrophysics Data System (ADS)

    Eng, Alex Yong Sheng; Chua, Chun Kiang; Pumera, Martin

    2015-11-01

    Chemical modification and functionalization of inherent functional groups within graphite oxide (GO) are essential aspects of graphene-based nano-materials used in wide-ranging applications. Despite extensive research, there remains some discrepancy in its structure, with current knowledge limited primarily to spectroscopic data from XPS, NMR and vibrational spectroscopies. We report herein an innovative electrochemistry-based approach. Four electroactive labels are chosen to selectively functionalize groups in GO, and quantification of each group is achieved by voltammetric analysis. This allows for the first time quantification of absolute amounts of each group, with a further advantage of distinguishing various carbonyl species: namely ortho- and para-quinones from aliphatic ketones. Intrinsic variations in the compositions of permanganate versus chlorate-oxidized GOs were thus observed. Principal differences include permanganate-GO exhibiting substantial quinonyl content, in comparison to chlorate-GO with the vast majority of its carbonyls as isolated ketones. The results confirm that carboxylic groups are rare in actuality, and are in fact entirely absent from chlorate-GO. These observations refine and advance our understanding of GO structure by addressing certain disparities in past models resulting from employment of different oxidation routes, with the vital implication that GO production methods cannot be used interchangeably in the manufacture of graphene-based devices.Chemical modification and functionalization of inherent functional groups within graphite oxide (GO) are essential aspects of graphene-based nano-materials used in wide-ranging applications. Despite extensive research, there remains some discrepancy in its structure, with current knowledge limited primarily to spectroscopic data from XPS, NMR and vibrational spectroscopies. We report herein an innovative electrochemistry-based approach. Four electroactive labels are chosen to selectively

  17. Tunable Oxygen Functional Groups as Electrocatalysts on Graphite Felt Surfaces for All-Vanadium Flow Batteries.

    PubMed

    Estevez, Luis; Reed, David; Nie, Zimin; Schwarz, Ashleigh M; Nandasiri, Manjula I; Kizewski, James P; Wang, Wei; Thomsen, Edwin; Liu, Jun; Zhang, Ji-Guang; Sprenkle, Vincent; Li, Bin

    2016-06-22

    A dual oxidative approach using O2 plasma followed by treatment with H2 O2 to impart oxygen functional groups onto the surface of a graphite felt electrode. When used as electrodes for an all-vanadium redox flow battery (VRB) system, the energy efficiency of the cell is enhanced by 8.2 % at a current density of 150 mA cm(-2) compared with one oxidized by thermal treatment in air. More importantly, by varying the oxidative techniques, the amount and type of oxygen groups was tailored and their effects were elucidated. It was found that O-C=O groups improve the cells performance whereas the C-O and C=O groups degrade it. The reason for the increased performance was found to be a reduction in the cell overpotential after functionalization of the graphite felt electrode. This work reveals a route for functionalizing carbon electrodes to improve the performance of VRB cells. This approach can lower the cost of VRB cells and pave the way for more commercially viable stationary energy storage systems that can be used for intermittent renewable energy storage. PMID:27184225

  18. Quantity of Hydrophobic Functional CH-Groups - Decisive for Soil Water Repellency Caused by Digestate Amendment

    NASA Astrophysics Data System (ADS)

    Voelkner, Amrei; Holthusen, Dörthe; Ellerbrock, Ruth H.; Horn, Rainer

    2015-04-01

    Anaerobic digestates are used as organic fertilizers; however, they are suspected to interfere negatively with soils. To investigate the relevance of the anaerobic digestates composition on potential wettability and contact angle of the soil, we mixed in a laboratory experiment 30 m³ ha-1 of anaerobic digestates derived from mechanically pre-treated substrates from maize and sugar beet with a homogenized Cambic Luvisol. Fourier transform infrared-spectra and diffuse reflectance infrared Fourier transform-spectra of particle intact and finely ground soilanaerobic digestates-mixtures were analyzed to determine the quantities of hydrophobic functional groups in the soil-anaerobic digestates-mixtures that are used here as an indicator for the potential hydrophobicity. The anaerobic digestates application increased the amount of hydrophobic functional groups of the mixtures and reduced the wettability of the soil. However, for intact particle samples an up to threefold higher amount of hydrophobic groups was found as compared to the finely ground ones, indicating a dilution effect of mechanical grinding on the effectivity of the organic matter that is presumably located as a coating on mineral soil particles. For the particle intact samples, the intensity of hydrophobic functional groups bands denoting hydrophobic brickstones in organic matter is indicative for the actual wettability of the soil-anaerobic digestates-mixtures.

  19. Tunable Oxygen Functional Groups as Electrocatalysts on Graphite Felt Surfaces for All-Vanadium Flow Batteries.

    PubMed

    Estevez, Luis; Reed, David; Nie, Zimin; Schwarz, Ashleigh M; Nandasiri, Manjula I; Kizewski, James P; Wang, Wei; Thomsen, Edwin; Liu, Jun; Zhang, Ji-Guang; Sprenkle, Vincent; Li, Bin

    2016-06-22

    A dual oxidative approach using O2 plasma followed by treatment with H2 O2 to impart oxygen functional groups onto the surface of a graphite felt electrode. When used as electrodes for an all-vanadium redox flow battery (VRB) system, the energy efficiency of the cell is enhanced by 8.2 % at a current density of 150 mA cm(-2) compared with one oxidized by thermal treatment in air. More importantly, by varying the oxidative techniques, the amount and type of oxygen groups was tailored and their effects were elucidated. It was found that O-C=O groups improve the cells performance whereas the C-O and C=O groups degrade it. The reason for the increased performance was found to be a reduction in the cell overpotential after functionalization of the graphite felt electrode. This work reveals a route for functionalizing carbon electrodes to improve the performance of VRB cells. This approach can lower the cost of VRB cells and pave the way for more commercially viable stationary energy storage systems that can be used for intermittent renewable energy storage.

  20. Functional characterization and phylogenetic analysis of acquired and intrinsic macrolide phosphotransferases in the Bacillus cereus group.

    PubMed

    Wang, Chao; Sui, Zhihai; Leclercq, Sébastien Olivier; Zhang, Gang; Zhao, Meilin; Chen, Weiqi; Feng, Jie

    2015-05-01

    The Bacillus cereus group is composed of Gram-positive spore-forming bacteria of clinical and ecological importance. More than 200 B. cereus group isolates have been sequenced. However, there are few reports of B. cereus group antibiotic resistance genes. This study identified two functional classes of macrolide phosphotransferases (Mphs) in the B. cereus group. Cluster A Mphs inactivate 14- and 15-membered macrolides while Cluster B Mphs inactivate 14-, 15- and 16-membered compounds. The genomic region surrounding the Cluster B Mph gene is related to various plasmid sequences, suggesting that this gene is an acquired resistance gene. In contrast, the Cluster A Mph gene is located in a chromosomal region conserved among all B. cereus group isolates, and data indicated that it was acquired early in the evolution of the group. Therefore, the Cluster A gene can be considered an intrinsic resistance gene. However, the gene itself is not present in all strains and our comparative genomics analyses showed that it is exchanged among strains of the B. cereus group by the mean of homologous recombination. These results provide an alternative mechanism to intrinsic resistance.

  1. Biofuel purification in zeolitic imidazolate frameworks: the significant role of functional groups.

    PubMed

    Zhang, Kang; Nalaparaju, Anjaiah; Chen, Yifei; Jiang, Jianwen

    2014-05-28

    A molecular simulation study is reported for biofuel purification in six zeolitic imidazolate frameworks (ZIF-8, -25, -71, -90, -96 and -97) with different functional groups. For pure ethanol and water, the predicted adsorption isotherms agree fairly well with experimental data. Hydrogen bonding has an important effect on the adsorption of ethanol and water. In hydrophilic ZIFs (ZIF-90, -96 and -97) with polar groups, adsorption capacities are higher than in hydrophobic counterparts (ZIF-8, -25 and -71). The atomic charges in symmetrically functionalized ZIF-8, -25, and -71 are found to have an indiscernible effect on adsorption, in remarkable contrast to asymmetrically functionalized ZIF-90, -96 and -97. For ethanol-water mixtures representing the biofuel, the selectivity of ethanol-water drops with increasing ethanol in mixtures. It is revealed that the selectivity is determined primarily by framework hydrophobicity as well as the cage size. Among the six ZIFs, ZIF-8 exhibits the highest selectivity. This simulation study provides a microscopic insight into the adsorption of ethanol and water in various ZIFs, reveals the significant role of functional groups in governing biofuel purification, and would facilitate the development of new nanoporous materials for high-efficacy liquid separation.

  2. Nanomechanical characterization of chemical interaction between gold nanoparticles and chemical functional groups

    PubMed Central

    2012-01-01

    We report on how to quantify the binding affinity between a nanoparticle and chemical functional group using various experimental methods such as cantilever assay, PeakForce quantitative nanomechanical property mapping, and lateral force microscopy. For the immobilization of Au nanoparticles (AuNPs) onto a microscale silicon substrate, we have considered two different chemical functional molecules of amine and catecholamine (here, dopamine was used). It is found that catecholamine-modified surface is more effective for the functionalization of AuNPs onto the surface than the amine-modified surface, which has been shown from our various experiments. The dimensionless parameter (i.e., ratio of binding affinity) introduced in this work from such experiments is useful in quantitatively depicting such binding affinity, indicating that the binding affinity and stability between AuNPs and catecholamine is approximately 1.5 times stronger than that between amine and AuNPs. Our study sheds light on the experiment-based quantitative characterization of the binding affinity between nanomaterial and chemical groups, which will eventually provide an insight into how to effectively design the functional material using chemical groups. PMID:23113991

  3. Linking avian communities and avian influenza ecology in southern Africa using epidemiological functional groups.

    PubMed

    Caron, Alexandre; de Garine-Wichatitsky, Michel; Ndlovu, Mduduzi; Cumming, Graeme S

    2012-01-01

    The ecology of pathogens, and particularly their emergence in multi-host systems, is complex. New approaches are needed to reduce superficial complexities to a level that still allows scientists to analyse underlying and more fundamental processes. One promising approach for simplification is to use an epidemiological-function classification to describe ecological diversity in a way that relates directly to pathogen dynamics. In this article, we develop and apply the epidemiological functional group (EFG) concept to explore the relationships between wild bird communities and avian influenza virus (AIV) in three ecosystems in southern Africa. Using a two year dataset that combined bird counts and bimonthly sampling for AIV, we allocated each bird species to a set of EFGs that captured two overarching epidemiological functions: the capacity of species to maintain AIV in the system, and their potential to introduce the virus. Comparing AIV prevalence between EFGs suggested that the hypothesis that anseriforms (ducks) and charadriiforms (waders) drive AIV epidemiology cannot entirely explain the high prevalence observed in some EFGs. If anseriforms do play an important role in AIV dynamics in each of the three ecosystems, the role of other species in the local maintenance of AIV cannot be ruled out. The EFG concept thus helped us to identify gaps in knowledge and to highlight understudied bird groups that might play a role in AIV epidemiology. In general, the use of EFGs has potential for generating a range of valuable insights in epidemiology, just as functional group approaches have done in ecology. PMID:23101696

  4. The central role of ketones in reversible and irreversible hydrothermal organic functional group transformations

    NASA Astrophysics Data System (ADS)

    Yang, Ziming; Gould, Ian R.; Williams, Lynda B.; Hartnett, Hilairy E.; Shock, Everett L.

    2012-12-01

    Studies of hydrothermal reactions involving organic compounds suggest complex, possibly reversible, reaction pathways that link functional groups from reduced alkanes all the way to oxidized carboxylic acids. Ketones represent a critical functional group because they occupy a central position in the reaction pathway, at the point where Csbnd C bond cleavage is required for the formation of the more oxidized carboxylic acids. The mechanisms for the critical bond cleavage reactions in ketones, and how they compete with other reactions are the focus of this experimental study. We studied a model ketone, dibenzylketone (DBK), in H2O at 300 °C and 70 MPa for up to 528 h. Product analysis was performed as a function of time at low DBK conversions to reveal the primary reaction pathways. Reversible interconversion between ketone, alcohol, alkene and alkane functional groups is observed in addition to formation of radical coupling products derived from irreversible Csbnd C and Csbnd H homolytic bond cleavage. The product distributions are time-dependent but the bond cleavage products dominate. The major products that accumulate at longer reaction times are toluene and larger, dehydrogenated structures that are initially formed by radical coupling. The hydrogen atoms generated by dehydrogenation of the coupling products are predominantly consumed in the formation of toluene. Even though bond cleavage products dominate, no carboxylic acids were observed on the timescale of the reactions under the chosen experimental conditions.

  5. First-principles study of the effect of functional groups on polyaniline backbone

    PubMed Central

    Chen, X. P.; Jiang, J. K.; Liang, Q. H.; Yang, N.; Ye, H. Y.; Cai, M.; Shen, L.; Yang, D. G.; Ren, T. L.

    2015-01-01

    We present a first-principles density functional theory study focused on how the chemical and electronic properties of polyaniline are adjusted by introducing suitable substituents on a polymer backbone. Analyses of the obtained energy barriers, reaction energies and minimum energy paths indicate that the chemical reactivity of the polyaniline derivatives is significantly enhanced by protonic acid doping of the substituted materials. Further study of the density of states at the Fermi level, band gap, HOMO and LUMO shows that both the unprotonated and protonated states of these polyanilines are altered to different degrees depending on the functional group. We also note that changes in both the chemical and electronic properties are very sensitive to the polarity and size of the functional group. It is worth noting that these changes do not substantially alter the inherent chemical and electronic properties of polyaniline. Our results demonstrate that introducing different functional groups on a polymer backbone is an effective approach to obtain tailored conductive polymers with desirable properties while retaining their intrinsic properties, such as conductivity. PMID:26584671

  6. Wetland macroinvertebrates of Prentiss Bay, Lake Huron, Michigan: diversity and functional group composition

    USGS Publications Warehouse

    Merritt, R.W.; Benbow, M.E.; Hudson, P.L.

    2002-01-01

    The Great Lakes support many fish and waterbirds that depend directly or indirectly on coastal wetlands during some portion of their life cycle. It is known that macroinvertebrates make up an important part of wetland food webs and ecosystem function; however, our understanding of species distribution within and among wetlands has only recently received attention. We investigated the macroinvertebrates of a freshwater marsh (Prentiss Bay) in the Les Chenaux Island Area of Northern Lake Huron, Michigan. Macroinvertebrate taxa diversity and functional feeding group composition were compared between two habitats. A shallow depositional habitat with higher vegetation diversity and little wave action was compared to a deeper erosional habitat with fewer plant species and more wave action. A total of 83 taxa were collected over the summer of 1996, representing two phyla (Arthropoda and Mollusca) and five classes (Arachnida, Bivalvia, Malacostraca, Gastropoda and Insecta). A total of 79 genera were identified, with 92% being insects (39 families composed of at least 73 genera). Of the total, 42 insect genera were common to both habitats,while relatively fewer were collected exclusively from the erosional compared the depositional habitat. When habitats were pooled, predators comprised about 50% of the functional group taxa, while gathering collectors and shredders each were about 20%. Filtering collectors and scrapers each represented < 10%. When comparing habitats, there was a relatively higher percentage of predators and shredders in the depositional habitat, while all other functional groups were lower. These data suggest that vegetation diversity, depth and wave action affect taxa composition and functional group organization of the Prentiss Bay marsh.

  7. Control of oxo-group functionalization and reduction of the uranyl ion.

    PubMed

    Arnold, Polly L; Pécharman, Anne-Frédérique; Lord, Rianne M; Jones, Guy M; Hollis, Emmalina; Nichol, Gary S; Maron, Laurent; Fang, Jian; Davin, Thomas; Love, Jason B

    2015-04-01

    Uranyl complexes of a large, compartmental N8-macrocycle adopt a rigid, "Pacman" geometry that stabilizes the U(V) oxidation state and promotes chemistry at a single uranyl oxo-group. We present here new and straightforward routes to singly reduced and oxo-silylated uranyl Pacman complexes and propose mechanisms that account for the product formation, and the byproduct distributions that are formed using alternative reagents. Uranyl(VI) Pacman complexes in which one oxo-group is functionalized by a single metal cation are activated toward single-electron reduction. As such, the addition of a second equivalent of a Lewis acidic metal complex such as MgN″2 (N″ = N(SiMe3)2) forms a uranyl(V) complex in which both oxo-groups are Mg functionalized as a result of Mg-N bond homolysis. In contrast, reactions with the less Lewis acidic complex [Zn(N″)Cl] favor the formation of weaker U-O-Zn dative interactions, leading to reductive silylation of the uranyl oxo-group in preference to metalation. Spectroscopic, crystallographic, and computational analysis of these reactions and of oxo-metalated products isolated by other routes have allowed us to propose mechanisms that account for pathways to metalation or silylation of the exo-oxo-group.

  8. Functionality of In vitro Reconstituted Group II Intron RmInt1-Derived Ribonucleoprotein Particles

    PubMed Central

    Molina-Sánchez, Maria D.; García-Rodríguez, Fernando M.; Toro, Nicolás

    2016-01-01

    The functional unit of mobile group II introns is a ribonucleoprotein particle (RNP) consisting of the intron-encoded protein (IEP) and the excised intron RNA. The IEP has reverse transcriptase activity but also promotes RNA splicing, and the RNA-protein complex triggers site-specific DNA insertion by reverse splicing, in a process called retrohoming. In vitro reconstituted ribonucleoprotein complexes from the Lactococcus lactis group II intron Ll.LtrB, which produce a double strand break, have recently been studied as a means of developing group II intron-based gene targeting methods for higher organisms. The Sinorhizobium meliloti group II intron RmInt1 is an efficient mobile retroelement, the dispersal of which appears to be linked to transient single-stranded DNA during replication. The RmInt1IEP lacks the endonuclease domain (En) and cannot cut the bottom strand to generate the 3′ end to initiate reverse transcription. We used an Escherichia coli expression system to produce soluble and active RmInt1 IEP and reconstituted RNPs with purified components in vitro. The RNPs generated were functional and reverse-spliced into a single-stranded DNA target. This work constitutes the starting point for the use of group II introns lacking DNA endonuclease domain-derived RNPs for highly specific gene targeting methods. PMID:27730127

  9. Unification of [FeFe]-hydrogenases into three structural and functional groups

    DOE PAGESBeta

    Poudel, Saroj; Tokmina-Lukaszewska, Monika; Colman, Daniel R.; Refai, Mohammed; Schut, Gerrit J.; King, Paul W.; Maness, Pin-Ching; Adams, Michael W. W.; Peters, John W.; Bothner, Brian; et al

    2016-05-27

    [FeFe]-hydrogenases (Hyd) are structurally diverse enzymes that catalyze the reversible oxidation of hydrogen (H2). Recent biochemical data demonstrate new functional roles for these enzymes, including those that function in electron bifurcation where an exergonic reaction is coupled with an endergonic reaction to drive the reversible oxidation/production of H2. To identify the structural determinants that underpin differences in enzyme functionality, a total of 714 homologous sequences of the catalytic subunit, HydA, were compiled. Bioinformatics approaches informed by biochemical data were then used to characterize differences in inferred quaternary structure, HydA active site protein environment, accessory iron-sulfur clusters in HydA, and regulatorymore » proteins encoded in HydA gene neighborhoods. HydA homologs were clustered into one of three classification groups, Group 1 (G1), Group 2 (G2), and Group 3 (G3). G1 enzymes were predicted to be monomeric while those in G2 and G3 were predicted to be multimeric and include HydB, HydC (G2/G3) and HydD (G3) subunits. Variation in the HydA active site and accessory iron-sulfur clusters did not vary by group type. Group-specific regulatory genes were identified in the gene neighborhoods of both G2 and G3 Hyd. Analyses of purified G2 and G3 enzymes by mass spectrometry strongly suggests that they are post-translationally modified by phosphorylation. In conclusion, these results suggest that bifurcation capability is dictated primarily by the presence of both HydB and HydC in Hyd complexes, rather than by variation in HydA.« less

  10. The use of natural abundance stable isotopic ratios to indicate the presence of oxygen-containing chemical linkages between cellulose and lignin in plant cell walls.

    PubMed

    Zhou, Youping; Stuart-Williams, Hilary; Farquhar, Graham D; Hocart, Charles H

    2010-06-01

    Qualitative and quantitative understanding of the chemical linkages between the three major biochemical components (cellulose, hemicellulose and lignin) of plant cell walls is crucial to the understanding of cell wall structure. Although there is convincing evidence for chemical bonds between hemicellulose and lignin and the absence of chemical bonds between hemicellulose and cellulose, there is no conclusive evidence for the presence of covalent bonds between cellulose and lignin. This is caused by the lack of selectivity of current GC/MS-, NMR- and IR-based methods for lignin characterisation as none of these techniques directly targets the possible ester and ether linkages between lignin and cellulose. We modified the widely-accepted "standard" three-step extraction method for isolating cellulose from plants by changing the order of the steps for hemicellulose and lignin removal (solubilisation with concentrated NaOH and oxidation with acetic acid-containing NaClO(2), respectively) so that cellulose and lignin could be isolated with the possible chemical bonds between them intact. These linkages were then cleaved with NaClO(2) reagent in aqueous media of contrasting (18)O/(16)O ratios. We produced cellulose with higher purity (a lower level of residual hemicellulose and no detectable lignin) than that produced by the "standard" method. Oxidative artefacts may potentially be introduced at the lignin removal stage; but testing showed this to be minimal. Cellulose samples isolated from processing plant-derived cellulose-lignin mixtures in media of contrasting (18)O/(16)O ratios were compared to provide the first quantitative evidence for the presence of oxygen-containing ester and ether bonds between cellulose and lignin in Zea mays leaves. However, no conclusive evidence for the presence or lack of similar bonds in Araucaria cunninghamii wood was obtained.

  11. Compatibility of functional groups in K[sup ow]-based QSARs: Application to nitro compounds

    SciTech Connect

    Banerjee, S.; Williams, C.L. )

    1993-10-01

    Nitro compounds are particular difficult to handle in simple K[sup ow]-based QSARs, owing to differences in their lipid-phase activity coefficients. These differences can be corrected, in part, through inclusion of a term in octanol solubility. A procedure for identifying potentially incompatible groups in a given QSAR is suggested. The quality of a QSAR is best if the interactions of the functional groups involved with octanol fall within a narrow range. These interactions are easily calculated by the UNIFAC method.

  12. Impact of Nanotopography and/or Functional Groups on Periodontal Ligament Cell Growth

    NASA Astrophysics Data System (ADS)

    Şaşmazel, Hilal Türkoğlu; Manolache, S.; Gümüşderelİoğlu, M.

    The main purpose of this contribution was to obtain COOH functionalities and/or nanotopographic changes on the surface of 3D, non-woven polyester fabric (NWPF) discs (12.5 mm in diameter) by using low pressure water/O2 plasma assisted treatments. The prepared discs were characterized by various methods after the plasma treatment. Periodontal ligament (PDL) fibroblasts were used in cell culture studies. The cell culture results showed that plasma treated 3D NWPF discs are favorable for PDL cell spreading, growth and viability due to the presence of functional groups and/or the nanotopography of their surfaces.

  13. On the stabilization mechanisms of organic functional groups on ZnO surfaces.

    PubMed

    Moreira, Ney Henrique; Domıinguez, Adriel; Frauenheim, Thomas; da Rosa, Andreia Luisa

    2012-11-28

    Density functional theory (DFT) calculations have been employed to investigate the interaction between ZnO-(101[combining macron]0) and (12[combining macron]10) surfaces and organic functional groups. We analyze the influence of the surface coverage on the geometries and binding energies under a dry environment. Our calculations show that coverages θ = 1 ML are favored under ligand-rich conditions and a dry environment. However, based on thermodynamic considerations we suggest that these ligands may not be stable against adsorption of liquid water and water vapor. PMID:23073244

  14. Approaching many-body localization from disordered Luttinger liquids via the functional renormalization group

    NASA Astrophysics Data System (ADS)

    Karrasch, C.; Moore, J. E.

    2015-09-01

    We study the interplay of interactions and disorder in a one-dimensional fermion lattice coupled adiabatically to infinite reservoirs. We employ both the functional renormalization group (FRG) as well as matrix product state techniques, which serve as an accurate benchmark for small systems. Using the FRG, we compute the length- and temperature-dependence of the conductance averaged over 104 samples for lattices as large as 105 sites. We identify regimes in which non-Ohmic power law behavior can be observed and demonstrate that the corresponding exponents can be understood by adapting earlier predictions obtained perturbatively for disordered Luttinger liquids. In the presence of both disorder and isolated impurities, the conductance has a universal single-parameter scaling form. This lays the groundwork for an application of the functional renormalization group to the realm of many-body localization.

  15. Amination of activated carbon for enhancing phenol adsorption: Effect of nitrogen-containing functional groups

    NASA Astrophysics Data System (ADS)

    Yang, Guo; Chen, Honglin; Qin, Hangdao; Feng, Yujun

    2014-02-01

    To study the contribution of different nitrogen-containing functional groups to enhancement of phenol adsorption, the aminated activated carbons (AC) were characterized by N2 adsorption/desorption, XPS, Boehm titration, and pH drift method and tested for adsorption behaviors of phenol. Adsorption isotherm fitting revealed that the Langmuir model was preferred for the aminated ACs. The adsorption capacity per unit surface area (qm/SSABET) was linearly correlated with the amount of pyridinic and pyrrolic N, which suggested that these two functional groups played a critical role in phenol adsorption. The enhancement of adsorption capacity was attributed to the strengthened π-π dispersion between phenol and basal plane of AC by pyridinic, pyrrolic N. The adsorption kinetics was found to follow the pseudo-second-order kinetic model, and intraparticle diffusion was one of the rate-controlling steps in the adsorption process.

  16. Assemblage patterns of fish functional groups relative to habitat connectivity and conditions in floodplain lakes

    USGS Publications Warehouse

    Miyazono, S.; Aycock, J.N.; Miranda, L.E.; Tietjen, T.E.

    2010-01-01

    We evaluated the influences of habitat connectivity and local environmental factors on the distribution and abundance patterns of fish functional groups in 17 floodplain lakes in the Yazoo River Basin, USA. The results of univariate and multivariate analyses showed that species-environmental relationships varied with the functional groups. Species richness and assemblage structure of periodic strategists showed strong and positive correlations with habitat connectivity. Densities of most equilibrium and opportunistic strategists decreased with habitat connectivity. Densities of certain equilibrium and opportunistic strategists increased with turbidity. Forested wetlands around the lakes were positively related to the densities of periodic and equilibrium strategists. These results suggest that decreases in habitat connectivity, forested wetland buffers and water quality resulting from environmental manipulations may cause local extinction of certain fish taxa and accelerate the dominance of tolerant fishes in floodplain lakes. ?? 2010 John Wiley & Sons A/S.

  17. Effects of acidic functional groups on dielectric properties of sodium alginates and carrageenans in water.

    PubMed

    Tsubaki, Shuntaro; Hiraoka, Masanori; Hadano, Shingo; Okamura, Kei; Ueda, Tadaharu; Nishimura, Hiroshi; Kashimura, Keiichiro; Mitani, Tomohiko

    2015-01-22

    This study investigated the dielectric properties of sodium alginates and carrageenans in water at frequencies between 100 MHz and 20 GHz in regard to water-hydrocolloid interactions via acidic functional groups. Both sodium alginates and carrageenans showed conduction loss at lower frequencies and dielectric loss at higher frequencies. Reduction and desulfation of sodium alginates and carrageenans, which decreased the numbers of acidic functional groups, decreased their conduction loss. In addition, H(+)-form carrageenans showed the highest ionic conduction. Correlational analysis of dielectric properties and related physical parameters showed that the loss tangent (tanδ) of the hydrocolloid solution was determined by the conductivity of the aqueous solution. Especially at pH below 2, strong H(+) conduction was associated with high tanδ probably due to the Grotthuss mechanism. The molecular dynamics of free water and H(+), viscosity conditions were also suggested to be associated with dielectric property of water-hydrocolloid system. PMID:25439871

  18. Synthesis and physicochemical properties of polysiloxane functionalized with aminoacetic acid groups

    NASA Astrophysics Data System (ADS)

    Lakiza, N. V.; Neudachina, L. K.

    2016-07-01

    Polysiloxane functionalized with aminoacetic acid groups was synthesized using sol-gel technology. Elemental analysis and FTIR spectroscopy were used to determine the composition of the polysiloxane show that it is a mesoporous material with a developed surface (109.4 m2/g). It was found that the selective properties of carboxymethylated polysiloxane towards transition metal ions simultaneously present in an ammonium acetate solution change in the order Zn < Cu > Ni > Co > Pb > Cd. It was shown that the sorption of copper(II) ions by carboxymethylated aminopropylpolysiloxane with particle sizes of 50-71 μm reaches its maximum level within 2 h; the rate-limiting step of the process is the chemical reaction between the ions and the polysiloxane functional groups; and the pseudo-second-order model is the best way of describing sorption.

  19. Group Forces in Instruction: Relationship to Learning. A Student and Teacher Training Program in Small Group Learning Functions.

    ERIC Educational Resources Information Center

    Mack, Richard G.; And Others

    The project's objectives were to increase achievement in mathematics, alter behavior in mathematics classes, and alter attitudes toward small-group work through training in small-group dynamics. The subjects were 85 10th grade geometry students assigned to one of two class periods (morning or afternoon). Within each class period, the students were…

  20. Geographic differences between functional groups in patterns of bird species richness in North America

    NASA Astrophysics Data System (ADS)

    Carnicer, Jofre; Díaz-Delgado, Ricardo

    2008-03-01

    Geographic divergences in patterns of species richness were studied for the terrestrial birds of North America using Breeding Bird Survey (BBS) census data subdivided for guild and migratory groups. Our aim was to study if species richness patterns for North American birds were best viewed as the convergent response of different groups to a common mechanism or as the result of several different processes. We observed opposite geographical patterns of species richness and differences in the variables associated with species richness depending on the guild or migratory status considered. Several ecological variables seem to regulate large-scale patterns of terrestrial bird species richness in North America, mainly temperature-, productivity- and landscape habitat structure-related variables. These variables are diverse and group-specific. For instance, the results supported the productivity hypothesis in migratory and frugivore groups and the winter tolerance hypothesis in residents. Habitat structure was also identified as an important factor driving species richness, total abundance and community body mass variation. Overall, our results indicate that the large-scale patterns of bird species richness are the result of several divergent, group-specific processes, and that understanding diversity gradients requires the identification of the functional ecological groups included.

  1. Determination of arterial input function in dynamic susceptibility contrast MRI using group independent component analysis technique

    NASA Astrophysics Data System (ADS)

    Chen, Sharon; Liu, Ho-Ling; Yang, Yihong; Hsu, Yuan-Yu; Chuang, Keh-Shih

    2006-12-01

    Quantification of cerebral blood flow (CBF) with dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) requires the determination of the arterial input function (AIF). The segmentation of surrounding tissue by manual selection is error-prone due to the partial volume artifacts. Independent component analysis (ICA) has the advantage in automatically decomposing the signals into interpretable components. Recently group ICA technique has been applied to fMRI study and showed reduced variance caused by motion artifact and noise. In this work, we investigated the feasibility and efficacy of the use of group ICA technique to extract the AIF. Both simulated and in vivo data were analyzed in this study. The simulation data of eight phantoms were generated using randomized lesion locations and time activity curves. The clinical data were obtained from spin-echo EPI MR scans performed in seven normal subjects. Group ICA technique was applied to analyze data through concatenating across seven subjects. The AIFs were calculated from the weighted average of the signals in the region selected by ICA. Preliminary results of this study showed that group ICA technique could not extract accurate AIF information from regions around the vessel. The mismatched location of vessels within the group reduced the benefits of group study.

  2. Preconversion catalytic deoxygenation of phenolic functional groups. Quarterly report, January 1--March 30, 1996

    SciTech Connect

    Kubiak, C.P.

    1996-12-31

    Over the course of the studies on catalytic deoxygenation of phenolic residues in coal by carbon monoxide, the author performed preliminary investigations into the removal of other heteroatom groups. This report describes the attempted carbonylation of phenyl amido complexes. These studies resulted in the surprisingly facile formation of amidines. The amidine group is the nitrogen analog of carboxylic acids and esters. This functional group combines the properties of an azomethane-like C=N double bond with an amide-like C-N single bond. This group, like the related allyl (C-C-C), aza-allyl (C-N-C), and carboxylato (O-C-O) groups, form a number of transition metal derivatives, with both early and late transition metals. Various bonding modes of the amidino group have been reported. However, most isolated complexes have the amidino ligand as a chelating ligand or bridging two metals. This is due to the preference of amidines to bond via the nitrogen lone pairs, in contrast to the {eta}3 bonding observed in metal-allyl complexes. The experimental section of the paper describes the synthesis of platinum complexes, X-ray diffraction data for one Pt complex, and its reaction with carbon monoxide. Results are presented on the crystal and molecular structure of a platinum complex.

  3. Temporal lobe contribution to perceptual function: A tale of three patient groups.

    PubMed

    Behrmann, M; Lee, A C H; Geskin, J Z; Graham, K S; Barense, M D

    2016-09-01

    There has been growing recognition of the contribution of medial and anterior temporal lobe structures to non-mnemonic functions, such as perception. To evaluate the nature of this contribution, we contrast the perceptual performance of three patient groups, all of whom have a perturbation of these temporal lobe structures. Specifically, we compare the profile of patients with focal hippocampal (HC) lesions, those with more extensive lesions to the medial temporal lobe (MTL) that include HC and perirhinal cortex (PrC), and those with congenital prosopagnosia (CP), whose deficit has been attributed to the disconnection of the anterior temporal lobe from more posterior structures. All participants completed a range of'oddity' tasks in which, on each trial, they determined which of four visual stimuli in a display was the'odd-one-out'. There were five stimulus categories including faces, scenes, objects (high and low ambiguity) and squares of different sizes. Comparisons were conducted separately for the HC, MTL and CP groups against their matched control groups and then the group data were compared to each other directly. The group profiles were easily differentiable. Whereas the HC group stood out for its difficulty in discriminating scenes and the CP group stood out for its disproportionate difficulty in discriminating faces with milder effects for scenes and high ambiguity objects, the MTL group evinced a more general discrimination deficit for faces, scenes and high ambiguity objects. The group differences highlight distinct profiles for each of the three groups and distinguish the signature perceptual impairments following more extended temporal lobe alterations. In the recent reconsideration of the role of the hippocampus and neocortex, Moscovitch and colleagues (Moscovitch et al., 2016) note that the medial temporal lobe structures play a role in non-mnemonic functions, such as perception, problem solving, decision-making and language. Here, we address this

  4. Sum-Rule Conserving Spectral Functions from the Numerical Renormalization Group

    NASA Astrophysics Data System (ADS)

    Weichselbaum, Andreas; von Delft, Jan

    2007-08-01

    We show how spectral functions for quantum impurity models can be calculated very accurately using a complete set of discarded numerical renormalization group eigenstates, recently introduced by Anders and Schiller. The only approximation is to judiciously exploit energy scale separation. Our derivation avoids both the overcounting ambiguities and the single-shell approximation for the equilibrium density matrix prevalent in current methods, ensuring that relevant sum rules hold rigorously and spectral features at energies below the temperature can be described accurately.

  5. β-Diversity of Functional Groups of Woody Plants in a Tropical Dry Forest in Yucatan

    PubMed Central

    López-Martínez, Jorge Omar; Sanaphre-Villanueva, Lucía; Dupuy, Juan Manuel; Hernández-Stefanoni, José Luis; Meave, Jorge Arturo; Gallardo-Cruz, José Alberto

    2013-01-01

    Two main theories have attempted to explain variation in plant species composition (β-diversity). Niche theory proposes that most of the variation is related to environment (environmental filtering), whereas neutral theory posits that dispersal limitation is the main driver of β-diversity. In this study, we first explored how α- and β-diversity of plant functional groups defined by growth form (trees, shrubs and lianas, which represent different strategies of resource partitioning), and dispersal syndrome (autochory, anemochory and zoochory, which represent differences in dispersal limitation) vary with successional age and topographic position in a tropical dry forest. Second, we examined the effects of environmental, spatial, and spatially-structured environmental factors on β-diversity of functional groups; we used the spatial structure of sampling sites as a proxy for dispersal limitation, and elevation, soil properties and forest stand age as indicators of environmental filtering. We recorded 200 species and 22,245 individuals in 276 plots; 120 species were trees, 41 shrubs and 39 lianas. We found that β-diversity was highest for shrubs, intermediate for lianas and lowest for trees, and was slightly higher for zoochorous than for autochorous and anemochorous species. All three dispersal syndromes, trees and shrubs varied in composition among vegetation classes (successional age and topographic position), whilst lianas did not. β-diversity was influenced mostly by proxies of environmental filtering, except for shrubs, for which the influence of dispersal limitation was more important. Stand age and topography significantly influenced α-diversity across functional groups, but showed a low influence on β-diversity –possibly due to the counterbalancing effect of resprouting on plant distribution and composition. Our results show that considering different plant functional groups reveals important differences in both α- and β-diversity patterns and

  6. The functional importance of blood group-active molecules in human red blood cells.

    PubMed

    Anstee, D J

    2011-01-01

    Antigens of 23 of the 30 human blood group systems are defined by the amino acid sequence of red cell membrane proteins. The antigens of DI, RH, RHAG, MNS, GE and CO systems are carried on blood group-active proteins (Band 3, D and CE polypeptides, RhAG, Glycophorins A and B, Glycophorins C and D and Aquaporin 1, respectively) which are expressed at high levels (>200,000 copies/red cell). These major proteins contribute to essential red cell functions either directly as membrane transporters and by providing linkage to the underlying red cell skeleton or by facilitating the membrane assembly of the protein complexes involved in these processes. The proteins expressing antigens of the remaining 17 blood group systems are much less abundant (<20,000 copies/red cell) and their functional importance for the circulating red cell is largely unknown. Human gene knock-outs (null phenotypes) have been described for many of these minor blood group-active proteins, but only absence of Kx glycoprotein has been clearly linked with pathology directly related to the function of circulating red cells. Recent evidence suggesting the normal quality control system for glycoprotein synthesis is altered during the latter stages of red cell production raises the possibility that many of these low abundance blood group-active proteins are vestigial. In sickle cell disease and polycythaemia vera, elevated Lutheran glycoprotein expression may contribute to pathology. Dyserythropoiesis with reduced antigen expression can result from mutations in the erythroid transcription factors GATA-1 and EKLF.

  7. Two group I ribozymes with different functions in a nuclear rDNA intron.

    PubMed Central

    Decatur, W A; Einvik, C; Johansen, S; Vogt, V M

    1995-01-01

    DiSSU1, a mobile intron in the nuclear rRNA gene of Didymium iridis, was previously reported to contain two independent catalytic RNA elements. We have found that both catalytic elements, renamed GIR1 and GIR2, are group I ribozymes, but with differing functionality. GIR2 carries out the several reactions associated with self-splicing. GIR1 carries out a hydrolysis reaction at an internal processing site (IPS-1). These conclusions are based on the catalytic properties of RNAs transcribed in vitro. Mutation of the P7 pairing segment of GIR2 abrogated self-splicing, while mutation of P7 in GIR1 abrogated hydrolysis at the IPS-1. Much of the P2 stem and all of the associated loop could be deleted without effect on self-splicing. These results are accounted for by a secondary structure model, in which a long P2 pairing segment brings the 5' splice site to the GIR2 catalytic core. GIR1 is the smallest natural group I ribozyme yet reported and is the first example of a group I ribozyme whose presumptive biological function is hydrolysis. We hypothesize that GIR1-mediated cleavage of the excised intron RNA functions in the generation and expression of the mRNA for the intron-encoded endonuclease I-DirI. Images PMID:7556099

  8. Prediction of cloud condensation nuclei activity for organic compounds using functional group contribution methods

    DOE PAGESBeta

    Petters, M. D.; Kreidenweis, S. M.; Ziemann, P. J.

    2016-01-19

    A wealth of recent laboratory and field experiments demonstrate that organic aerosol composition evolves with time in the atmosphere, leading to changes in the influence of the organic fraction to cloud condensation nuclei (CCN) spectra. There is a need for tools that can realistically represent the evolution of CCN activity to better predict indirect effects of organic aerosol on clouds and climate. This work describes a model to predict the CCN activity of organic compounds from functional group composition. Following previous methods in the literature, we test the ability of semi-empirical group contribution methods in Köhler theory to predict themore » effective hygroscopicity parameter, kappa. However, in our approach we also account for liquid–liquid phase boundaries to simulate phase-limited activation behavior. Model evaluation against a selected database of published laboratory measurements demonstrates that kappa can be predicted within a factor of 2. Simulation of homologous series is used to identify the relative effectiveness of different functional groups in increasing the CCN activity of weakly functionalized organic compounds. Hydroxyl, carboxyl, aldehyde, hydroperoxide, carbonyl, and ether moieties promote CCN activity while methylene and nitrate moieties inhibit CCN activity. The model can be incorporated into scale-bridging test beds such as the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) to evaluate the evolution of kappa for a complex mix of organic compounds and to develop suitable parameterizations of CCN evolution for larger-scale models.« less

  9. Surface modification influencing adsorption of red wine constituents: The role of functional groups

    NASA Astrophysics Data System (ADS)

    Mierczynska-Vasilev, Agnieszka; Smith, Paul A.

    2016-11-01

    The adsorption of wine constituents at solid surfaces is important in applications such as filtration and membrane fouling, binding to tanks and fittings and interactions with processing aids such as bentonite. The interaction of wine constituents with surfaces is mediated through adsorbed wine components, where the type of constituents, amount, orientation, and conformation are of consequence for the surface response. This study examines the effect of surface chemical functionalities on the adsorption of red wine constituents. Plasma-polymerized films rich in amine, carboxyl, hydroxyl, formyl and methyl functional groups were generated on solid substrates whereas, glycidyltrimethylammonium chloride was covalently attached to allylamine plasma-polymer modified surface and poly(sodium styrenesulfonate) was electrostatically adsorbed to an amine plasma-polymerized surface. The surface chemical functionalities were characterized by X-ray photoelectron spectroscopy. The ability of different substrates to adsorb red wine constituents was evaluated by quartz crystal microbalance and atomic force microscopy. The results showed that substrates modified with -SO3H and -COOH groups can adsorb more of the wine nitrogen-containing compounds whereas -NH2 and -NR3 groups encourage carbon-containing compounds adsorption. Red wine constituents after filtration were adsorbed in higher extend on -NR3 and -CHO surfaces. The -OH modified surfaces had the lowest ability to absorb wine components.

  10. Functional group-specific traits drive phytoplankton dynamics in the oligotrophic ocean

    PubMed Central

    Alexander, Harriet; Rouco, Mónica; Haley, Sheean T.; Wilson, Samuel T.; Karl, David M.; Dyhrman, Sonya T.

    2015-01-01

    A diverse microbial assemblage in the ocean is responsible for nearly half of global primary production. It has been hypothesized and experimentally demonstrated that nutrient loading can stimulate blooms of large eukaryotic phytoplankton in oligotrophic systems. Although central to balancing biogeochemical models, knowledge of the metabolic traits that govern the dynamics of these bloom-forming phytoplankton is limited. We used eukaryotic metatranscriptomic techniques to identify the metabolic basis of functional group-specific traits that may drive the shift between net heterotrophy and autotrophy in the oligotrophic ocean. Replicated blooms were simulated by deep seawater (DSW) addition to mimic nutrient loading in the North Pacific Subtropical Gyre, and the transcriptional responses of phytoplankton functional groups were assayed. Responses of the diatom, haptophyte, and dinoflagellate functional groups in simulated blooms were unique, with diatoms and haptophytes significantly (95% confidence) shifting their quantitative metabolic fingerprint from the in situ condition, whereas dinoflagellates showed little response. Significantly differentially abundant genes identified the importance of colimitation by nutrients, metals, and vitamins in eukaryotic phytoplankton metabolism and bloom formation in this system. The variable transcript allocation ratio, used to quantify transcript reallocation following DSW amendment, differed for diatoms and haptophytes, reflecting the long-standing paradigm of phytoplankton r- and K-type growth strategies. Although the underlying metabolic potential of the large eukaryotic phytoplankton was consistently present, the lack of a bloom during the study period suggests a crucial dependence on physical and biogeochemical forcing, which are susceptible to alteration with changing climate. PMID:26460011

  11. Microstructures and functional groups of Nannochloropsis sp. cells with arsenic adsorption and lipid accumulation.

    PubMed

    Sun, Jing; Cheng, Jun; Yang, Zongbo; Li, Ke; Zhou, Junhu; Cen, Kefa

    2015-10-01

    The pore structures and surface morphological characteristics of Nannochloropsis sp. cells with arsenic adsorption were initially investigated by N2-adsorption analysis and scanning electronic microscopy. Functional groups of cells were analysed by Fourier-transform infrared spectrometry and X-ray photoelectron spectroscopy. Total surface area of microalgal cells increased from 0.54 m(2)/g to 1.80 m(2)/g upon arsenic adsorption. The external cell surface area increased. More wrinkles and measles-like granules formed on the surfaces as a result of arsenic toxicity. Arsenic ions blocked cell pores and decreased the average pore diameter and total pore volume. Ether cross-linked structures in the algaenan layer of cell walls were disrupted as the percentage of C-O functional groups decreased. These functional groups underwent complexation reactions with arsenic ions. Accumulation of polyunsaturated fatty acids decreased because of oxidative stresses induced by arsenic. The increase in generation of short-chain saturated fatty acids was favourable for the production of quality biodiesel. PMID:26210144

  12. Functional group-specific traits drive phytoplankton dynamics in the oligotrophic ocean.

    PubMed

    Alexander, Harriet; Rouco, Mónica; Haley, Sheean T; Wilson, Samuel T; Karl, David M; Dyhrman, Sonya T

    2015-11-01

    A diverse microbial assemblage in the ocean is responsible for nearly half of global primary production. It has been hypothesized and experimentally demonstrated that nutrient loading can stimulate blooms of large eukaryotic phytoplankton in oligotrophic systems. Although central to balancing biogeochemical models, knowledge of the metabolic traits that govern the dynamics of these bloom-forming phytoplankton is limited. We used eukaryotic metatranscriptomic techniques to identify the metabolic basis of functional group-specific traits that may drive the shift between net heterotrophy and autotrophy in the oligotrophic ocean. Replicated blooms were simulated by deep seawater (DSW) addition to mimic nutrient loading in the North Pacific Subtropical Gyre, and the transcriptional responses of phytoplankton functional groups were assayed. Responses of the diatom, haptophyte, and dinoflagellate functional groups in simulated blooms were unique, with diatoms and haptophytes significantly (95% confidence) shifting their quantitative metabolic fingerprint from the in situ condition, whereas dinoflagellates showed little response. Significantly differentially abundant genes identified the importance of colimitation by nutrients, metals, and vitamins in eukaryotic phytoplankton metabolism and bloom formation in this system. The variable transcript allocation ratio, used to quantify transcript reallocation following DSW amendment, differed for diatoms and haptophytes, reflecting the long-standing paradigm of phytoplankton r- and K-type growth strategies. Although the underlying metabolic potential of the large eukaryotic phytoplankton was consistently present, the lack of a bloom during the study period suggests a crucial dependence on physical and biogeochemical forcing, which are susceptible to alteration with changing climate. PMID:26460011

  13. Functional group-specific traits drive phytoplankton dynamics in the oligotrophic ocean.

    PubMed

    Alexander, Harriet; Rouco, Mónica; Haley, Sheean T; Wilson, Samuel T; Karl, David M; Dyhrman, Sonya T

    2015-11-01

    A diverse microbial assemblage in the ocean is responsible for nearly half of global primary production. It has been hypothesized and experimentally demonstrated that nutrient loading can stimulate blooms of large eukaryotic phytoplankton in oligotrophic systems. Although central to balancing biogeochemical models, knowledge of the metabolic traits that govern the dynamics of these bloom-forming phytoplankton is limited. We used eukaryotic metatranscriptomic techniques to identify the metabolic basis of functional group-specific traits that may drive the shift between net heterotrophy and autotrophy in the oligotrophic ocean. Replicated blooms were simulated by deep seawater (DSW) addition to mimic nutrient loading in the North Pacific Subtropical Gyre, and the transcriptional responses of phytoplankton functional groups were assayed. Responses of the diatom, haptophyte, and dinoflagellate functional groups in simulated blooms were unique, with diatoms and haptophytes significantly (95% confidence) shifting their quantitative metabolic fingerprint from the in situ condition, whereas dinoflagellates showed little response. Significantly differentially abundant genes identified the importance of colimitation by nutrients, metals, and vitamins in eukaryotic phytoplankton metabolism and bloom formation in this system. The variable transcript allocation ratio, used to quantify transcript reallocation following DSW amendment, differed for diatoms and haptophytes, reflecting the long-standing paradigm of phytoplankton r- and K-type growth strategies. Although the underlying metabolic potential of the large eukaryotic phytoplankton was consistently present, the lack of a bloom during the study period suggests a crucial dependence on physical and biogeochemical forcing, which are susceptible to alteration with changing climate.

  14. Aspartyl Oxidation Catalysts That Dial In Functional Group Selectivity, along with Regio- and Stereoselectivity

    PubMed Central

    2016-01-01

    A remarkable aspect of enzyme evolution is the portability of catalytic mechanisms for fundamentally different chemical reactions. For example, aspartyl proteases, which contain two active site carboxylic acid groups, catalyze the hydrolysis of amide bonds, while glycosyltransferases (and glycosyl hydrolases), which often also contain two active site carboxylates, have evolved to form (or break) glycosidic bonds. However, neither catalyst exhibits cross-reactivity in the intracellular environment. The large, macromolecular architectures of these biocatalysts tailor their active sites to their precise, divergent functions. The analogous portability of a small-molecule catalyst for truly orthogonal chemical reactivity is rare. Herein, we report aspartic acid containing peptides that can be directed to different sectors of a substrate for which the danger of cross-reactivity looms large. A transiently formed aspartyl peracid catalyst can participate either as an electrophilic oxidant to catalyze alkene epoxidation or as a nucleophilic oxidant to mediate the Baeyer–Villiger oxidation (BVO) of ketones. We show in this study that an appended peptide sequence can dictate the mode of reactivity for this conserved catalytic functional group within a substrate that has the potential to undergo both alkene epoxidation and BVO; in both cases the additional aspects of chemical selectivity (regio- and stereoselectivity) are high. This sequence-dependent tuning of a common catalytic moiety for functional group selective reactions constitutes a biomimetic strategy that may impact late-stage diversification of complex polyfunctional molecules. PMID:27800556

  15. Interpersonal distance regulates functional grouping tendencies of agents in team sports.

    PubMed

    Passos, Pedro; Milho, João; Fonseca, Sofia; Borges, João; Araújo, Duarte; Davids, Keith

    2011-01-01

    The authors examined whether, similar to collective agent behaviors in complex, biological systems (e.g., schools of fish and colonies of ants), performers in team sports displayed functional coordination tendencies, based on local interaction rules during performance. To investigate this issue, they used videogrammetry and digitizing procedures to observe interpersonal interactions in common 4 versus 2 + 2 subphases of the team sport of rugby union, involving 16 participants aged between 16 and 17 years of age. They observed pattern-forming dynamics in attacking subunits (n = 4 players) attempting to penetrate 2 defensive lines (n = 2 players in each). Data showed that within each attacking subunit, the 4 players displayed emergent functional grouping tendencies that differed between the 2 defensive lines. Results confirmed that grouping tendencies in attacking subunits of team games are sensitive to different task constraints, such as relative positioning to nearest defenders. It was concluded that running correlations were particularly useful for measuring the level of interpersonal coordination in functional grouping tendencies within attacking subunits.

  16. Life span and structure of ephemeral root modules of different functional groups from a desert system.

    PubMed

    Liu, Bo; He, Junxia; Zeng, Fanjiang; Lei, Jiaqiang; Arndt, Stefan K

    2016-07-01

    The terminal branch orders of plant root systems have been proposed as short-lived 'ephemeral' modules specialized for resource absorption. The occurrence of ephemeral root modules has so far only been reported for a temperate tree species and it is unclear if the concept also applies to other woody (shrub, tree) and herb species. Fine roots of 12 perennial dicotyledonous herb, shrub and tree species were monitored for two growing seasons using a branch-order classification, sequential sampling and rhizotrons in the Taklamakan desert. Two root modules existed in all three plant functional groups. Among the first five branch orders, the first two (perennial herbs, shrubs) or three (trees) root orders were ephemeral and had a primary anatomical structure, high nitrogen (N) concentrations, high respiration rates and very short life spans of 1-4 months, whereas the last two branch orders in all functional groups were perennial, with thicker diameters, no or collapsed cortex, distinct secondary growth, low N concentrations, low respiration rates, but much longer life spans. Ephemeral, short-lived root modules and long-lived, persistent root modules seem to be a general feature across many plant functional groups and could represent a basic root system design.

  17. Prediction of cloud condensation nuclei activity for organic compounds using functional group contribution methods

    NASA Astrophysics Data System (ADS)

    Petters, M. D.; Kreidenweis, S. M.; Ziemann, P. J.

    2016-01-01

    A wealth of recent laboratory and field experiments demonstrate that organic aerosol composition evolves with time in the atmosphere, leading to changes in the influence of the organic fraction to cloud condensation nuclei (CCN) spectra. There is a need for tools that can realistically represent the evolution of CCN activity to better predict indirect effects of organic aerosol on clouds and climate. This work describes a model to predict the CCN activity of organic compounds from functional group composition. Following previous methods in the literature, we test the ability of semi-empirical group contribution methods in Köhler theory to predict the effective hygroscopicity parameter, kappa. However, in our approach we also account for liquid-liquid phase boundaries to simulate phase-limited activation behavior. Model evaluation against a selected database of published laboratory measurements demonstrates that kappa can be predicted within a factor of 2. Simulation of homologous series is used to identify the relative effectiveness of different functional groups in increasing the CCN activity of weakly functionalized organic compounds. Hydroxyl, carboxyl, aldehyde, hydroperoxide, carbonyl, and ether moieties promote CCN activity while methylene and nitrate moieties inhibit CCN activity. The model can be incorporated into scale-bridging test beds such as the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) to evaluate the evolution of kappa for a complex mix of organic compounds and to develop suitable parameterizations of CCN evolution for larger-scale models.

  18. Magneto-Sensitive Adsorbents Modified by Functional Nitrogen-Containing Groups

    NASA Astrophysics Data System (ADS)

    Melnyk, Inna V.; Gdula, Karolina; Dąbrowski, Andrzej; Zub, Yuriy L.

    2016-02-01

    In order to obtain amino-functionalized silica materials with magnetic core, one-step synthesis was carried out. Several materials, differ in number and structure of amino groups, were synthesized on the basis of sol-gel method. The synthesized materials were examined by several analytical techniques. The presence and content of amino groups were measured by using Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy and acid-base titration, respectively. Specific surface areas were measured by nitrogen/adsorption desorption isotherms. It was proved that sol-gel approach leads to obtain materials with high content of amino groups built into their surfaces (in the range 1.6-2.7 mmol/g). As-obtained materials were tested as potential adsorbents for copper(II) ions. The received maximum adsorption capacities were in the range 0.4-0.7 mmol/g.

  19. Magneto-Sensitive Adsorbents Modified by Functional Nitrogen-Containing Groups.

    PubMed

    Melnyk, Inna V; Gdula, Karolina; Dąbrowski, Andrzej; Zub, Yuriy L

    2016-12-01

    In order to obtain amino-functionalized silica materials with magnetic core, one-step synthesis was carried out. Several materials, differ in number and structure of amino groups, were synthesized on the basis of sol-gel method. The synthesized materials were examined by several analytical techniques. The presence and content of amino groups were measured by using Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy and acid-base titration, respectively. Specific surface areas were measured by nitrogen/adsorption desorption isotherms. It was proved that sol-gel approach leads to obtain materials with high content of amino groups built into their surfaces (in the range 1.6-2.7 mmol/g). As-obtained materials were tested as potential adsorbents for copper(II) ions. The received maximum adsorption capacities were in the range 0.4-0.7 mmol/g. PMID:26842794

  20. Synthesis and characterization of bifunctional surfaces with tunable functional group pairs

    NASA Astrophysics Data System (ADS)

    Galloway, John M.; Kung, Mayfair; Kung, Harold H.

    2016-06-01

    Grafting of pairs of functional groups onto a silica surface was demonstrated by tethering both terminals of an organochlorosilane precursor molecule, Cl2(CH3)Si(CH2)4(CO)(OSi(i-Pr)2)(CH2)2Si(CH3)Cl2, that possess a cleavable silyl ester bond, onto a silica surface. Hydrolytic cleavage of the silyl ester bond of the grafted molecule resulted in the generation of organized pairs of carboxylic acid and organosilanol groups. This organosilanol moiety was easily transformed into other functional groups through condensation reactions to form, together with the neighboring acid group, pairs such as carboxylic acid/secondary amine, carboxylic acid/pyridine, and carboxylic acid/phosphine. In the case of carboxylic acid/amine pairing, there was evidence of the formation of amide. A sample grafted with amine-carboxylic acid pairs was three times more active (per free amine) than a sample without such pairs for the nitroaldol condensation of 4-nitrobenzaldehyde and nitromethane.

  1. Coumestan inhibits radical-induced oxidation of DNA: is hydroxyl a necessary functional group?

    PubMed

    Xi, Gao-Lei; Liu, Zai-Qun

    2014-06-18

    Coumestan is a natural tetracycle with a C═C bond shared by a coumarin moiety and a benzofuran moiety. In addition to the function of the hydroxyl group on the antioxidant activity of coumestan, it is worth exploring the influence of the oxygen-abundant scaffold on the antioxidant activity as well. In this work, seven coumestans containing electron-withdrawing and electron-donating groups were synthesized to evaluate the abilities to trap 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(•+)), 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH), and galvinoxyl radical, respectively, and to inhibit the oxidations of DNA mediated by (•)OH, Cu(2+)/glutathione (GSH), and 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH), respectively. It was found that all of the coumestans used herein can quench the aforementioned radicals and can inhibit (•)OH-, Cu(2+)/GSH-, and AAPH-induced oxidations of DNA. In particular, substituent-free coumestan exhibits higher ability to quench DPPH and to inhibit AAPH-induced oxidation of DNA than Trolox. In addition, nonsubstituted coumestan shows a similar ability to inhibit (•)OH- and Cu(2+)/GSH-induced oxidations of DNA relative to that of Trolox. The antioxidant effectiveness of the coumestan can be attributed to the lactone in the coumarin moiety and, therefore, a hydroxyl group may not be a necessary functional group for coumestan to be an antioxidant.

  2. Sulfhydryl-group modifications of Torpedo Californica acetylcholine receptor: subunit localization and effects on function

    SciTech Connect

    McNamee, M.G.; Yee, A.S.

    1986-05-01

    The effects of thiol-group modification on acetylcholine receptor (ACHR) function were measured using purified Torpedo ACHR reconstituted into soybean lipid vesicles. N-Phenyl-maleimide (NPM) was used to modify sulfhydryl groups in ACHR in the absence of any prior reduction by dithiotheitol. Modification by NPM led to the inhibition of ion channel activity without a detectable effect on ligand binding. The ion flux inhibition by NPM primarily affected channel activation, since the initial rates of activation decreased over a wide range of carbamylcholine concentrations. The /sup 3/H-NPM subunit labelling pattern of ACHR (a multisubunit membrane protein with ..cap alpha../sub 2/..beta gamma..delta stoichiometry) revealed preferential labelling of the ..gamma.. subunit. At high NPM concentration, the number of sulfhydryl groups on the ..gamma.. subunit that could be modified with NPM was two. Detergent was required during labelling for functionally relevant thiol group modifications, and most of the label was protected from protease digestion in the reconstituted membranes. These results are consistent with the presence of the NPM modification in a bilayer and/or cytoplasmic domain. Analysis of cyanogen bromide and trypsin fragments indicates that the labeled cysteines may be located in the postulated amphipathic helix region of the ..gamma.. subunit.

  3. Molecular weight distribution and functional group profiles of TEMPO-oxidized lyocell fibers.

    PubMed

    Milanovic, Jovana; Schiehser, Sonja; Milanovic, Predrag; Potthast, Antje; Kostic, Mirjana

    2013-10-15

    The effects of TEMPO-mediated oxidation, performed with NaClO, a catalytic amount of NaBr, and 2,2',6,6'-tetramethylpiperidine-1-oxy radical (TEMPO), were studied on lyocell fibers by means of GPC using multiple detection and group-selective fluorescence labeling according to the CCOA and FDAM methodology. The applied method determines functional group content as a sum parameter, as well as functional group profiles in relation to the molecular weight of the cellulose fibers. Both the CHO and COOH profiles, as well as molecular weight alterations, were analyzed. A significant decrease in the average molecular weight was obtained during the first hour of TEMPO-mediated oxidation, but prolonged oxidation time resulted in no strong additional chain scission. Significant amounts of COOH groups were introduced in the high molecular weight fractions by the oxidation with higher concentrations of NaClO (2.42-9.67 mmol NaClO/g fiber) after modification times of 1h or longer.

  4. Functional group composition of organic aerosol from combustion emissions and secondary processes at two contrasted urban environments

    NASA Astrophysics Data System (ADS)

    El Haddad, Imad; Marchand, Nicolas; D'Anna, Barbara; Jaffrezo, Jean Luc; Wortham, Henri

    2013-08-01

    The quantification of major functional groups in atmospheric organic aerosol (OA) provides a constraint on the types of compounds emitted and formed in atmospheric conditions. This paper presents functional group composition of organic aerosol from two contrasted urban environments: Marseille during summer and Grenoble during winter. Functional groups were determined using a tandem mass spectrometry approach, enabling the quantification of carboxylic (RCOOH), carbonyl (RCOR‧), and nitro (RNO2) functional groups. Using a multiple regression analysis, absolute concentrations of functional groups were combined with those of organic carbon derived from different sources in order to infer the functional group contents of different organic aerosol fractions. These fractions include fossil fuel combustion emissions, biomass burning emissions and secondary organic aerosol (SOA). Results clearly highlight the differences between functional group fingerprints of primary and secondary OA fractions. OA emitted from primary sources is found to be moderately functionalized, as about 20 carbons per 1000 bear one of the functional groups determined here, whereas SOA is much more functionalized, as in average 94 carbons per 1000 bear a functional group under study. Aging processes appear to increase both RCOOH and RCOR‧ functional group contents by nearly one order of magnitude. Conversely, RNO2 content is found to decrease with photochemical processes. Finally, our results also suggest that other functional groups significantly contribute to biomass smoke and SOA. In particular, for SOA, the overall oxygen content, assessed using aerosol mass spectrometer measurements by an O:C ratio of 0.63, is significantly higher than the apparent O:C* ratio of 0.17 estimated based on functional groups measured here. A thorough examination of our data suggests that this remaining unexplained oxygen content can be most probably assigned to alcohol (ROH), organic peroxides (ROOH

  5. A meta‐analysis of functional group responses to forest recovery outside of the tropics

    PubMed Central

    Ezard, Thomas H. G.; Martin, Philip A.; Newton, Adrian C.; Doncaster, C. Patrick

    2015-01-01

    Abstract Both active and passive forest restoration schemes are used in degraded landscapes across the world to enhance biodiversity and ecosystem service provision. Restoration is increasingly also being implemented in biodiversity offset schemes as compensation for loss of natural habitat to anthropogenic development. This has raised concerns about the value of replacing old‐growth forest with plantations, motivating research on biodiversity recovery as forest stands age. Functional diversity is now advocated as a key metric for restoration success, yet it has received little analytical attention to date. We conducted a meta‐analysis of 90 studies that measured differences in species richness for functional groups of fungi, lichens, and beetles between old‐growth control and planted or secondary treatment forests in temperate, boreal, and Mediterranean regions. We identified functional‐group–specific relationships in the response of species richness to stand age after forest disturbance. Ectomycorrhizal fungi averaged 90 years for recovery to old‐growth values (between 45 years and unrecoverable at 95% prediction limits), and epiphytic lichens took 180 years to reach 90% of old‐growth values (between 140 years and never for recovery to old‐growth values at 95% prediction limits). Non‐saproxylic beetle richness, in contrast, decreased as stand age of broadleaved forests increased. The slow recovery by some functional groups essential to ecosystem functioning makes old‐growth forest an effectively irreplaceable biodiversity resource that should be exempt from biodiversity offsetting initiatives. PMID:26040756

  6. Gas-Phase Reactivity of Carboxylic Acid Functional Groups with Carbodiimides

    PubMed Central

    Prentice, Boone M.; Gilbert, Joshua D.; Stutzman, John R.; Forrest, William P.; McLuckey, Scott A.

    2012-01-01

    Gas-phase modification of carboxylic acid functionalities is performed via ion/ion reactions with carbodiimide reagents [N-cyclohexyl-N′-(2-morpholinoethyl)carbodiimide (CMC) and [3-(3-Ethylcarbodiimide-1-yl)propyl]trimethylaminium (ECPT). Gas-phase ion/ion covalent chemistry requires the formation of a long-lived complex. In this instance, the complex is stabilized by an electrostatic interaction between the fixed charge quaternary ammonium group of the carbodiimide reagent cation and the analyte dianion. Subsequent activation results in characteristic loss of an isocyanate derivative from one side of the carbodiimide functionality, a signature for this covalent chemistry. The resulting amide bond is formed on the analyte at the site of the original carboxylic acid. Reactions involving analytes that do not contain available carboxylic acid groups (e.g., they have been converted to sodium salts) or reagents that do not have the carbodiimide functionality do not undergo a covalent reaction. This chemistry is demonstrated using PAMAM generation 0.5 dendrimer, ethylenediaminetetraacetic acid (EDTA), and the model peptide DGAILDGAILD. This work demonstrates the selective gas-phase covalent modification of carboxylic acid functionalities. PMID:23208744

  7. Various fates of neuronal progenitor cells observed on several different chemical functional groups

    NASA Astrophysics Data System (ADS)

    Liu, Xi; Wang, Ying; He, Jin; Wang, Xiu-Mei; Cui, Fu-Zhai; Xu, Quan-Yuan

    2011-12-01

    Neuronal progenitor cells cultured on gold-coated glass surfaces modified by different chemical functional groups, including hydroxyl (-OH), carboxyl (-COOH), amino (-NH2), bromo (-Br), mercapto (-SH), - Phenyl and methyl (-CH3), were studied here to investigate the influence of surface chemistry on the cells' adhesion, morphology, proliferation and functional gene expression. Focal adhesion staining indicated in the initial culture stage cells exhibited morphological changes in response to different chemical functional groups. Cells cultured on -NH2 grafted surface displayed focal adhesion plaque and flattened morphology and had the largest contact area. However, their counter parts on -CH3 grafted surface displayed no focal adhesion and rounded morphology and had the smallest contact area. After 6 days culture, the proliferation trend was as follows: -NH2 > -SH> -COOH> - Phenyl > - Br > -OH> -CH3. To determine the neural functional properties of the cells affected by surface chemistry, the expression of glutamate decarboxylase (GAD67), nerve growth factor (NGF) and brainderived neurotrophic factor (BDNF) were characterized. An increase of GAD67 expression was observed on -NH2, -COOH and -SH grafted surfaces, while no increase in NGF and BDNF expression was observed on any chemical surfaces. These results highlight the importance of surface chemistry in the fate determination of neuronal progenitor cells, and suggest that surface chemistry must be considered in the design of biomaterials for neural tissue engineering.

  8. 14 CFR Section 11 - Functional Classification-Operating Expenses of Group II and Group III Air Carriers

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... operations and the maintenance and repair of property and equipment of all types and classes, regardless of... periodic maintenance operations and the maintenance and repair of property and equipment of all types and... in function 5400 Maintenance, or function 6400 Aircraft and Traffic Servicing. 5400Maintenance....

  9. Renormalization group improved computation of correlation functions in theories with nontrivial phase diagram

    NASA Astrophysics Data System (ADS)

    Codello, Alessandro; Tonero, Alberto

    2016-07-01

    We present a simple and consistent way to compute correlation functions in interacting theories with nontrivial phase diagram. As an example we show how to consistently compute the four-point function in three dimensional Z2 -scalar theories. The idea is to perform the path integral by weighting the momentum modes that contribute to it according to their renormalization group (RG) relevance, i.e. we weight each mode according to the value of the running couplings at that scale. In this way, we are able to encode in a loop computation the information regarding the RG trajectory along which we are integrating. We show that depending on the initial condition, or initial point in the phase diagram, we obtain different behaviors of the four-point function at the endpoint of the flow.

  10. Sequential Linker Installation: Precise Placement of Functional Groups in Multivariate Metal-Organic Frameworks

    SciTech Connect

    Yuan, S; Lu, WG; Chen, YP; Zhang, Q; Liu, TF; Feng, DW; Wang, X; Qin, JS; Zhou, HC

    2015-03-11

    A unique strategy, sequential linker installation (SLI), has been developed to construct multivariate MOFs with functional groups precisely positioned. PCN-700, a Zr-MOF with eight-connected Zr6O4(OH)(8)(H2O)(4) clusters, has been judiciously designed; the Zr-6 clusters in this MOF are arranged in such a fashion that, by replacement of terminal OH-/H2O ligands, subsequent insertion of linear dicarboxylate linkers is achieved. We demonstrate that linkers with distinct lengths and functionalities can be sequentially installed into PCN-700. Single-crystal to single-crystal transformation is realized so that the positions of the subsequently installed linkers are pinpointed via single-crystal X-ray diffraction analyses. This methodology provides a powerful tool to construct multivariate MOFs with precisely positioned functionalities in the desired proximity, which would otherwise be difficult to achieve.

  11. C-H Coupling Reactions Directed by Sulfoxides: Teaching an Old Functional Group New Tricks.

    PubMed

    Pulis, Alexander P; Procter, David J

    2016-08-16

    Sulfoxides are classical functional groups for directing the stoichiometric metalation and functionalization of C-H bonds. In recent times, sulfoxides have been given a new lease on life owing to the development of modern synthetic methods that have arisen because of their unique reactivity. They have recently been used in catalytic C-H activation proceeding via coordination of an internal sulfoxide to a metal or through the action of an external sulfoxide ligand. Furthermore, sulfoxides are able to capture nucleophiles and electrophiles to give sulfonium salts, which subsequently enable the formation of C-C bonds at the expense of C-H bonds. This Review summarizes a renaissance period in the application of sulfoxides arising from their versatility in directing C-H functionalization. PMID:27409984

  12. Star Formation as a Function of Neutral Hydrogen Gas Density in Local Group Galaxies

    NASA Astrophysics Data System (ADS)

    Carlson, Erika K.; Madore, Barry F.; Freedman, Wendy L.

    2016-06-01

    We present a study of the efficiency and timescales of star formation as a function of local neutral hydrogen gas density in four Local Group galaxies: M33, NGC 6822, the LMC, and the SMC. In this work, we conceptualize the process of star formation as a cycle of two major phases - (1) a gas dynamics phase in which neutral hydrogen gas coalesces into clouds, and (2) a stellar phase in which stars have formed and interrupt further gas coalescence during their active lifetimes. By examining the spatial distribution and number densities of stars on maps of neutral hydrogen, we estimate the timescale of the gas coalescence phase relative to the timescale of the stellar phase and infer an efficiency of star formation as a function of neutral hydrogen gas density. From these timescales and efficiencies, we will calculate star formation rates as a function of neutral hydrogen gas density in these galaxies.

  13. Functionalized quantum dots induce proinflammatory responses in vitro: the role of terminal functional group-associated endocytic pathways

    NASA Astrophysics Data System (ADS)

    Zhang, Yijuan; Pan, Hong; Zhang, Pengfei; Gao, Ningning; Lin, Yi; Luo, Zichao; Li, Ping; Wang, Ce; Liu, Lanlan; Pang, Daiwen; Cai, Lintao; Ma, Yifan

    2013-06-01

    PEGylation has been applied as an effective strategy of surface functionalization to improve the stability and reduce non-specific binding of quantum dots (QDs). However, its effects on the proinflammatory properties of QDs and the underlying mechanism have not been well elucidated yet. Herein, the proinflammatory effects of PEGylated CdSe/ZnS QDs with an amphiphilic polymer coating (PEG-pQDs) were investigated in human pulmonary epithelial cells and macrophages by evaluating the cytokine/chemokine production. The results showed that the proinflammatory effects of PEG-pQDs were strongly associated with the functional groups (-COOH, -NH2, -OH, and -OCH3) at the end of PEG chain. COOH-PEG-pQDs demonstrated the most proinflammatory effects followed by NH2-PEG-pQDs and HO-PEG-pQDs with CH3O-PEG-pQDs exhibiting the least proinflammatory effects. The proinflammatory effects of PEG-pQDs relied on lipid raft- and class A scavenger receptor (SRA)-dependent endocytic pathways as well as the downstream NF-κB and MAPK signaling cascades. COOH-PEG-pQDs were selectively internalized by lipid raft- and SRA-mediated endocytosis, which consequently activated NF-κB signaling pathway. On the other hand, NH2-PEG-pQDs and HO-PEG-pQDs were mostly internalized via lipid raft-mediated endocytosis, thereby activating p38 MAPK/AP-1 signaling cascades. These data revealed a critical role of terminal functional group-associated endocytic pathways in the proinflammatory responses induced by PEGylated QDs in human pulmonary epithelial cells and macrophages.PEGylation has been applied as an effective strategy of surface functionalization to improve the stability and reduce non-specific binding of quantum dots (QDs). However, its effects on the proinflammatory properties of QDs and the underlying mechanism have not been well elucidated yet. Herein, the proinflammatory effects of PEGylated CdSe/ZnS QDs with an amphiphilic polymer coating (PEG-pQDs) were investigated in human pulmonary epithelial

  14. Water Desalination through Zeolitic Imidazolate Framework Membranes: Significant Role of Functional Groups.

    PubMed

    Gupta, Krishna M; Zhang, Kang; Jiang, Jianwen

    2015-12-01

    A molecular simulation study is reported for water desalination through five zeolitic imidazolate framework (ZIF) membranes, namely ZIF-25, -71, -93, -96, and -97. The five ZIFs possess identical rho-topology but differ in functional groups. The rejection of salt (NaCl) is found to be around 97% in ZIF-25, and 100% in the other four ZIFs. The permeance ranges from 27 to 710 kg/(m(2)·h·bar), about one∼two orders of magnitude higher compared with commercial reverse osmosis membranes. Due to a larger aperture size da, ZIF-25, -71, and -96 exhibit a much higher water flux than ZIF-93 and -97; however, the flux in ZIF-25, -71, and -96 is governed by the polarity of functional group rather than da. With the hydrophobic CH3 group, ZIF-25 has the highest flux despite the smallest da among ZIF-25, -71, and -96. The lifetime of hydrogen bonding in ZIF-25 is shorter than that in ZIF-71 and -96. Furthermore, water molecules undergo a fast flushing motion in ZIF-25, but frequent jumping in ZIF-96 and particularly in ZIF-97. An Arrhenius-type relationship is found between water flux in ZIF-25 and temperature, and the activation energy is predicted to be 6.5 kJ/mol. This simulation study provides a microscopic insight into water desalination in a series of ZIFs, reveals the key factors (aperture size and polarity of functional group) governing water flux, and suggests that ZIF-25 might be an interesting reverse osmosis membrane for high-performance water desalination.

  15. Comparison of statistical tests for group differences in brain functional networks.

    PubMed

    Kim, Junghi; Wozniak, Jeffrey R; Mueller, Bryon A; Shen, Xiaotong; Pan, Wei

    2014-11-01

    Brain functional connectivity has been studied by analyzing time series correlations in regional brain activities based on resting-state fMRI data. Brain functional connectivity can be depicted as a network or graph defined as a set of nodes linked by edges. Nodes represent brain regions and an edge measures the strength of functional correlation between two regions. Most of existing work focuses on estimation of such a network. A key but inadequately addressed question is how to test for possible differences of the networks between two subject groups, say between healthy controls and patients. Here we illustrate and compare the performance of several state-of-the-art statistical tests drawn from the neuroimaging, genetics, ecology and high-dimensional data literatures. Both real and simulated data were used to evaluate the methods. We found that Network Based Statistic (NBS) performed well in many but not all situations, and its performance critically depends on the choice of its threshold parameter, which is unknown and difficult to choose in practice. Importantly, two adaptive statistical tests called adaptive sum of powered score (aSPU) and its weighted version (aSPUw) are easy to use and complementary to NBS, being higher powered than NBS in some situations. The aSPU and aSPUw tests can also be applied to adjust for covariates. Between the aSPU and aSPUw tests, they often, but not always, performed similarly with neither one as a uniform winner. On the other hand, Multivariate Matrix Distance Regression (MDMR) has been applied to detect group differences for brain connectivity; with the usual choice of the Euclidean distance, MDMR is a special case of the aSPU test. Consequently NBS, aSPU and aSPUw tests are recommended to test for group differences in functional connectivity. PMID:25086298

  16. Improving plant functional groups for dynamic models of biodiversity: at the crossroads between functional and community ecology.

    PubMed

    Isabelle, Boulangeat; Pauline, Philippe; Sylvain, Abdulhak; Roland, Douzet; Luc, Garraud; Sébastien, Lavergne; Sandra, Lavorel; Jérémie, Van Es; Pascal, Vittoz; Wilfried, Thuiller

    2012-11-01

    The pace of on-going climate change calls for reliable plant biodiversity scenarios. Traditional dynamic vegetation models use plant functional types that are summarized to such an extent that they become meaningless for biodiversity scenarios. Hybrid dynamic vegetation models of intermediate complexity (hybrid-DVMs) have recently been developed to address this issue. These models, at the crossroads between phenomenological and process-based models, are able to involve an intermediate number of well-chosen plant functional groups (PFGs). The challenge is to build meaningful PFGs that are representative of plant biodiversity, and consistent with the parameters and processes of hybrid-DVMs. Here, we propose and test a framework based on few selected traits to define a limited number of PFGs, which are both representative of the diversity (functional and taxonomic) of the flora in the Ecrins National Park, and adapted to hybrid-DVMs. This new classification scheme, together with recent advances in vegetation modeling, constitutes a step forward for mechanistic biodiversity modeling. PMID:24403847

  17. Tree Diametric Increment and Litterfall Production in an Eastern Amazonian Forest: the Role of Functional Groups

    NASA Astrophysics Data System (ADS)

    Camargo, P. B. D.; Ferreira, M. L.; Oliveira Junior, R. C.; Saleska, S. R.

    2014-12-01

    Tree growth is a biotic variable of great importance in understanding the dynamics of tree communities and may be used as a tool in studies of biological or climate modeling. Some climate models predict more recurrent climate anomalies in this century, which may alter the functioning of tropical forests with serious structural and demographic implications. The present study aimed to evaluate the profile of tree growth and litterfall production in an eastern Amazon forest, which has suffered recent climatic disturbances. We contrasted different functional groups based on wood density (stem with 0.55; 0.56-0.7; >0.7 g cm-3), light availability (crown illumination index; high illuminated crown - IIC1 until shaded crown - IIC5), and, size class (trees 10-22.5; 22.6-35; 35.1-55; 55,1-90; >90 cm dbh). Tree diameter increment was monthly measured from November 2011 to September 2013 by using dendrometer bands installed on 850 individuals from different families. Litterfall was collected in 64 circular traps, oven dried and weighed, separated into leaves, twigs, reproductive parts and miscellaneous. During the rainy season the sampled trees had the highest rates of tree diametric increment. When analyzing the data by functional groups, large trees had faster growth, but when grouped by wood density, trees with wood density up to 0.55 and between 0.56 and 0.7 g cm-3 had the fastest rates of growth. When grouped by crown illumination index, trees exposed to higher levels of light grew more in comparison to partially shaded trees. Maximum daily air temperature and precipitation were the most important environmental variables in determining the diametric increment profile of the trees. Litterfall production was estimated to be 7.1 Mg ha-1.year-1 and showed a strong seasonal pattern, with dry season production being higher than in the rainy season. Leaves formed the largest fraction of the litterfall, followed by twigs, reproductive parts, and finally miscellaneous. These

  18. Polycomb Group (PcG) Proteins and Human Cancers: Multifaceted Functions and Therapeutic Implications

    PubMed Central

    Wang, Wei; Qin, Jiang-Jiang; Voruganti, Sukesh; Nag, Subhasree; Zhou, Jianwei; Zhang, Ruiwen

    2016-01-01

    Polycomb group (PcG) proteins are transcriptional repressors that regulate several crucial developmental and physiological processes in the cell. More recently, they have been found to play important roles in human carcinogenesis and cancer development and progression. The deregulation and dysfunction of PcG proteins often lead to blocking or inappropriate activation of developmental pathways, enhancing cellular proliferation, inhibiting apoptosis, and increasing the cancer stem cell population. Genetic and molecular investigations of PcG proteins have long been focused on their PcG functions. However, PcG proteins have recently been shown to exert non-polycomb functions, contributing to the regulation of diverse cellular functions. We and others have demonstrated that PcG proteins regulate the expression and function of several oncogenes and tumor suppressor genes in a PcG-independent manner, and PcG proteins are associated with the survival of patients with cancer. In this review, we summarize the recent advances in the research on PcG proteins, including both the polycomb-repressive and non-polycomb functions. We specifically focus on the mechanisms by which PcG proteins play roles in cancer initiation, development, and progression. Finally, we discuss the potential value of PcG proteins as molecular biomarkers for the diagnosis and prognosis of cancer, and as molecular targets for cancer therapy. PMID:26227500

  19. Toward a standardized structural-functional group connectome in MNI space.

    PubMed

    Horn, Andreas; Blankenburg, Felix

    2016-01-01

    The analysis of the structural architecture of the human brain in terms of connectivity between its subregions has provided profound insights into its underlying functional organization and has coined the concept of the "connectome", a structural description of the elements forming the human brain and the connections among them. Here, as a proof of concept, we introduce a novel group connectome in standard space based on a large sample of 169 subjects from the Enhanced Nathan Kline Institute-Rockland Sample (eNKI-RS). Whole brain structural connectomes of each subject were estimated with a global tracking approach, and the resulting fiber tracts were warped into standard stereotactic (MNI) space using DARTEL. Employing this group connectome, the results of published tracking studies (i.e., the JHU white matter and Oxford thalamic connectivity atlas) could be largely reproduced directly within MNI space. In a second analysis, a study that examined structural connectivity between regions of a functional network, namely the default mode network, was reproduced. Voxel-wise structural centrality was then calculated and compared to others' findings. Furthermore, including additional resting-state fMRI data from the same subjects, structural and functional connectivity matrices between approximately forty thousand nodes of the brain were calculated. This was done to estimate structure-function agreement indices of voxel-wise whole brain connectivity. Taken together, the combination of a novel whole brain fiber tracking approach and an advanced normalization method led to a group connectome that allowed (at least heuristically) performing fiber tracking directly within MNI space. Such an approach may be used for various purposes like the analysis of structural connectivity and modeling experiments that aim at studying the structure-function relationship of the human connectome. Moreover, it may even represent a first step toward a standard DTI template of the human brain

  20. Impact of dendrimer surface functional groups on the release of doxorubicin from dendrimer carriers.

    PubMed

    Zhang, Mengen; Guo, Rui; Kéri, Mónika; Bányai, István; Zheng, Yun; Cao, Mian; Cao, Xueyan; Shi, Xiangyang

    2014-02-13

    Generation 5 (G5) poly(amidoamine) dendrimers with acetyl (G5.NHAc), glycidol hydroxyl (G5.NGlyOH), and succinamic acid (G5.SAH) terminal groups were used to physically encapsulate an anticancer drug doxorubicin (DOX). Both UV-vis spectroscopy and multiple NMR techniques including one-dimensional NMR and two-dimensional NMR were applied to investigate the interactions between different dendrimers and DOX. The influence of the surface functional groups of G5 dendrimers on the DOX encapsulation, release kinetics, and cancer cell inhibition effect was investigated. We show that all three types of dendrimers are able to effectively encapsulate DOX and display therapeutic inhibition effect to cancer cells, which is solely associated with the loaded DOX. The relatively stronger interactions of G5.NHAc or G5.NGlyOH dendrimers with DOX than that of G5.SAH dendrimers with DOX demonstrated by NMR techniques correlate well with the slow release rate of DOX from G5.NHAc/DOX or G5.NGlyOH/DOX complexes. In contrast, the demonstrated weak interaction between G5.SAH and DOX causes a fast release of DOX, suggesting that the G5.SAH/DOX complex may not be a proper option for further in vivo research. Our findings suggest that the dendrimer surface functional groups are crucial for further design of multifunctional dendrimer-based drug delivery systems for various biomedical applications.

  1. Differences in menstrual bleeding characteristics, functional status, and attitudes toward menstruation in three groups of women.

    PubMed

    Geller, S E; Harlow, S D; Bernstein, S J

    1999-05-01

    This report examines differences in bleeding characteristics, functional status, and attitudes toward menstruation among three groups of women: (1) women who complain of abnormal uterine bleeding (AUB), (2) women who have similar menstrual patterns as those complaining of AUB but who do not perceive themselves to have abnormal bleeding, and (3) women without evidence of prolonged or excessive bleeding. Women who complain of AUB and women with heavy bleeding but not complaining of AUB, although similar on two important menstrual symptoms (very heavy bleeding or episodes of unusually heavy bleeding) differ on a number of other menstrual characteristics, including the frequency of short cycles, the probability of having an abnormally long period, and reporting of unusually heavy bleeding lasting longer than 1 day. Whether women reported concerns with menstruation or not, the majority of women in this analysis had fairly negative attitudes toward menstruation. However, this negativity toward menstruation did not translate into women wanting a hysterectomy, even for those with heavy bleeding. The major difference among the three groups of women was the strong negative effect of AUB on functional status. A majority of women complaining of AUB reported that the bleeding interfered significantly with their daily routine, making them unable to function at work and at home. These results suggest that although the main complaint of women with AUB is very heavy bleeding, a number of other specific menstrual characteristics differentiate women with AUB from other women with very heavy bleeding who do not perceive the bleeding to be problematic. The complaint of AUB appears to be related to how significantly bleeding affects daily functioning. Therefore, an important factor to assess when considering treatment of AUB is the extent to which bleeding symptoms significantly affect functional status.

  2. Group 2 innate lymphoid cells express functional NKp30 receptor inducing type 2 cytokine production1

    PubMed Central

    Salimi, Maryam; Xue, Luzheng; Jolin, Helen; Hardman, Clare; Cousins, David J.; McKenzie, Andrew N.J.; Ogg, Graham S.

    2016-01-01

    Group 2 innate lymphoid cells (ILC2) are important in effector functions for eliciting allergic inflammation, parasite defence, epithelial repair and lipid homeostasis. ILC2 lack rearranged antigen-specific receptors, and while many soluble factors such as cytokines and lipid mediators can influence ILC2, direct interaction of these cells with microenvironment and other cells has been less explored. Natural cytotoxicity receptors are expressed by subsets of ILC1 and ILC3 and thought to be important for their effector function, but have not been shown to be expressed by ILC2. Therefore, we sought to investigate the expression and functional properties of the natural cytotoxicity receptor NKp30 on human group 2 innate lymphoid cells. A subset of ex vivo and cultured ILC2 express NKp30 that upon interaction with its cognate activatory ligand B7-H6 induces rapid production of type 2 cytokines. This interaction can be blocked by NKp30 blocking antibody and an inhibitory ligand, galectin-3. Higher expression of B7-H6 was observed in lesional skin biopsies of patients with atopic dermatitis; and incubation of keratinocytes with pro-inflammatory and type 2 cytokines upregulated B7-H6 leading to increased ILC2 cytokine production. NKp30-B7-H6 interaction is a novel cell contact mechanism that mediates activation of ILC2 and identifies a potential target for the development of novel therapeutics for atopic dermatitis and other atopic diseases. PMID:26582946

  3. The synthesis of desired functional groups on PEI microgel particles for biomedical and environmental applications

    NASA Astrophysics Data System (ADS)

    Sahiner, Nurettin; Demirci, Sahin; Sahiner, Mehtap; Al-Lohedan, Hamad

    2015-11-01

    Polyethyleneimine (PEI) microgels were synthesized by micro emulsion polymerization technique and converted to positively charged forms by chemical treatments with various modifying agents with different functional groups, such as 2-bromoethanol (-OH), 4-bromobutyronitrile (-CN), 2-bromoethylamine hydrobromide (-NH2), and glycidol (-OH). The functionalization of PEI microgels was confirmed by FT-IR, TGA and zeta potential measurements. Furthermore, a second modification of the modified PEI microgels was induced on 4-bromo butyronitrile-modified PEI microgels (PEI-CN) by amidoximation, to generate new functional groups on the modified PEI microgels. The PEI and modified PEI microgels were also tested for their antimicrobial effects against various bacteria such as Bacillus subtilis ATCC 6633, Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 25323. Moreover, the PEI-based particles were used for removal of organic dyes such as methyl orange (MO) and congo red (CR). The absorption capacity of PEI-based microgels increased with modification from 101.8 mg/g to 218.8 mg/g with 2-bromoethylamine, 216.2 m/g with 1-bromoethanol, and 224.5 mg/g with 4-bromobutyronitrile for MO. The increase in absorption for CR dyes was from 347.3 mg/g to 390.4 mg/g with 1-bromoethanol, 399.6 mg/g with glycidol, and 349.9 mg/g with 4-bromobutyronitrile.

  4. Detecting Functional Groups of Arabidopsis Mutants by Metabolic Profiling and Evaluation of Pleiotropic Responses

    PubMed Central

    Hofmann, Jörg; Börnke, Frederik; Schmiedl, Alfred; Kleine, Tatjana; Sonnewald, Uwe

    2011-01-01

    Metabolic profiles and fingerprints of Arabidopsis thaliana plants with various defects in plastidic sugar metabolism or photosynthesis were analyzed to elucidate if the genetic mutations can be traced by comparing their metabolic status. Using a platform of chromatographic and spectrometric tools data from untargeted full MS scans as well as from selected metabolites including major carbohydrates, phosphorylated intermediates, carboxylates, free amino acids, major antioxidants, and plastidic pigments were evaluated. Our key observations are that by multivariate statistical analysis each mutant can be separated by a unique metabolic signature. Closely related mutants come close. Thus metabolic profiles of sugar mutants are different but more similar than those of photosynthesis mutants. All mutants show pleiotropic responses mirrored in their metabolic status. These pleiotropic responses are typical and can be used for separating and grouping of the mutants. Our findings show that metabolite fingerprints can be taken to classify mutants and hence may be used to sort genes into functional groups. PMID:22639613

  5. Biomass Vanillin-Derived Polymeric Microspheres Containing Functional Aldehyde Groups: Preparation, Characterization, and Application as Adsorbent.

    PubMed

    Zhang, Huanyu; Yong, Xueyong; Zhou, Jinyong; Deng, Jianping; Wu, Youping

    2016-02-01

    The contribution reports the first polymeric microspheres derived from a biomass, vanillin. It reacted with methacryloyl chloride, providing monomer vanillin methacrylate (VMA), which underwent suspension polymerization in aqueous media and yielded microspheres in high yield (>90 wt %). By controlling the N2 bubbling mode and by optimizing the cosolvent for dissolving the solid monomer, the microspheres were endowed with surface pores, demonstrated by SEM images and mercury intrusion porosimetry measurement. Taking advantage of the reactive aldehyde groups, the microspheres further reacted with glycine, thereby leading to a novel type of Schiff-base chelating material. The functionalized microspheres demonstrated remarkable adsorption toward Cu(2+) (maximum, 135 mg/g) which was taken as representative for metal ions. The present study provides an unprecedented class of biobased polymeric microspheres showing large potentials as adsorbents in wastewater treatment. Also importantly, the reactive aldehyde groups may enable the microspheres to be used as novel materials for immobilizing biomacromolecules, e.g. enzymes. PMID:26752344

  6. Biomass Vanillin-Derived Polymeric Microspheres Containing Functional Aldehyde Groups: Preparation, Characterization, and Application as Adsorbent.

    PubMed

    Zhang, Huanyu; Yong, Xueyong; Zhou, Jinyong; Deng, Jianping; Wu, Youping

    2016-02-01

    The contribution reports the first polymeric microspheres derived from a biomass, vanillin. It reacted with methacryloyl chloride, providing monomer vanillin methacrylate (VMA), which underwent suspension polymerization in aqueous media and yielded microspheres in high yield (>90 wt %). By controlling the N2 bubbling mode and by optimizing the cosolvent for dissolving the solid monomer, the microspheres were endowed with surface pores, demonstrated by SEM images and mercury intrusion porosimetry measurement. Taking advantage of the reactive aldehyde groups, the microspheres further reacted with glycine, thereby leading to a novel type of Schiff-base chelating material. The functionalized microspheres demonstrated remarkable adsorption toward Cu(2+) (maximum, 135 mg/g) which was taken as representative for metal ions. The present study provides an unprecedented class of biobased polymeric microspheres showing large potentials as adsorbents in wastewater treatment. Also importantly, the reactive aldehyde groups may enable the microspheres to be used as novel materials for immobilizing biomacromolecules, e.g. enzymes.

  7. Multi-Walled Carbon Nanotube Functionalization by Radical Addition Using Hydroxymethylene Groups.

    PubMed

    Rodríguez-Jiménez, Rubén; Alonso-Núñez, Gabriel; Paraguay-Delgado, Francisco; Espinoza-Gómez, Heriberto; Vélez-López, Ernesto; Rogel-Hernández, Eduardo

    2016-01-01

    Synthetic methodology and characterization of multi-walled carbon nanotubes (MWCNTs) function- alized with hydroxymethylene groups are reported. The MWCNTs were synthesized by the spray pyrolysis technique using toluene as carbon source and ferrocene as catalyst. Hydroxymethylation of MWCNTs was carried out by methanol using benzoyl peroxide (BPO) at different quantities (300 to 900 mg); the optimum BPO quantity was 300 mg. The resulting materials were characterized by FT-IR, Raman Spectroscopy, Thermal Gravimetric Analysis (TGA) and Transmission Electron Microscopy (TEM). The presence of the hydroxymethylene group on the MWCNTs surface was demonstrated by FT-IR, Raman Spectroscopy, TGA, EDS, TEM and Mass Spectrometry. The func- tionalized MWCNTs were not damaged by this methodology. PMID:27398563

  8. Acidity of the amidoxime functional group in aqueous solution. A combined experimental and computational study

    DOE PAGESBeta

    Mehio, Nada; Lashely, Mark A.; Nugent, Joseph W.; Tucker, Lyndsay; Correia, Bruna; Do-Thanh, Chi-Linh; Dai, Sheng; Hancock, Robert D.; Bryantsev, Vyacheslav S.

    2015-01-26

    Poly(acrylamidoxime) adsorbents are often invoked in discussions of mining uranium from seawater. It has been demonstrated repeatedly in the literature that the success of these materials is due to the amidoxime functional group. While the amidoxime-uranyl chelation mode has been established, a number of essential binding constants remain unclear. This is largely due to the wide range of conflicting pKa values that have been reported for the amidoxime functional group in the literature. To resolve this existing controversy we investigated the pKa values of the amidoxime functional group using a combination of experimental and computational methods. Experimentally, we used spectroscopicmore » titrations to measure the pKa values of representative amidoximes, acetamidoxime and benzamidoxime. Computationally, we report on the performance of several protocols for predicting the pKa values of aqueous oxoacids. Calculations carried out at the MP2 or M06-2X levels of theory combined with solvent effects calculated using the SMD model provide the best overall performance with a mean absolute error of 0.33 pKa units and 0.35 pKa units, respectively, and a root mean square deviation of 0.46 pKa units and 0.45 pKa units, respectively. Finally, we employ our two best methods to predict the pKa values of promising, uncharacterized amidoxime ligands. Hence, our study provides a convenient means for screening suitable amidoxime monomers for future generations of poly(acrylamidoxime) adsorbents used to mine uranium from seawater.« less

  9. Acidity of the amidoxime functional group in aqueous solution. A combined experimental and computational study

    SciTech Connect

    Mehio, Nada; Lashely, Mark A.; Nugent, Joseph W.; Tucker, Lyndsay; Correia, Bruna; Do-Thanh, Chi-Linh; Dai, Sheng; Hancock, Robert D.; Bryantsev, Vyacheslav S.

    2015-01-26

    Poly(acrylamidoxime) adsorbents are often invoked in discussions of mining uranium from seawater. It has been demonstrated repeatedly in the literature that the success of these materials is due to the amidoxime functional group. While the amidoxime-uranyl chelation mode has been established, a number of essential binding constants remain unclear. This is largely due to the wide range of conflicting pKa values that have been reported for the amidoxime functional group in the literature. To resolve this existing controversy we investigated the pKa values of the amidoxime functional group using a combination of experimental and computational methods. Experimentally, we used spectroscopic titrations to measure the pKa values of representative amidoximes, acetamidoxime and benzamidoxime. Computationally, we report on the performance of several protocols for predicting the pKa values of aqueous oxoacids. Calculations carried out at the MP2 or M06-2X levels of theory combined with solvent effects calculated using the SMD model provide the best overall performance with a mean absolute error of 0.33 pKa units and 0.35 pKa units, respectively, and a root mean square deviation of 0.46 pKa units and 0.45 pKa units, respectively. Finally, we employ our two best methods to predict the pKa values of promising, uncharacterized amidoxime ligands. Hence, our study provides a convenient means for screening suitable amidoxime monomers for future generations of poly(acrylamidoxime) adsorbents used to mine uranium from seawater.

  10. Ecological Significance of a Geomorphic Stream Classification: Species and Functional Group Composition of Riparian Plant Communities

    NASA Astrophysics Data System (ADS)

    Shaw, J. R.; Cooper, D. J.

    2014-12-01

    We tested the ecological significance of a geomorphic classification of Sonoran Desert ephemeral stream channels based on channel plan-form, degree of lateral confinement, and boundary material composition. This typology has been shown to discriminate among channel geometry and hydraulic characteristics for bedrock, bedrock with alluvium, incised alluvium, braided, and piedmont headwater channels. We examined stream reach-scale relationships of geomorphic stream types to the relative cover and density of perennial plant species and functional groups, and identified the dominant fluvial drivers, within riparian communities at 101 ephemeral stream reaches on the U.S. Army Yuma Proving Ground and Barry M. Goldwater Air Force Range in southwestern Arizona, USA. Nonparametric multivariate analysis of variance showed that species and functional group composition differed significantly among geomorphic stream types, both in terms of relative cover and density. Partitioning of among-site multivariate dissimilarity revealed that species compositional differences between stream types were caused largely by variation in the cover and density of the most common members of the regional flora. Distinctive functional group composition among reach types resulted from differences in the cover and density of drought-deciduous shrubs and subshrubs, evergreen trees and shrubs, and photosynthetic-stemmed trees. Comparison of environmental and biotic dissimilarity matrices highlighted the role of channel gradient as the dominant abiotic driver of riparian plant community composition, with stream channel elevation and width:depth providing additional explanatory power. Distinctive riparian plant community composition among the geomorphic stream types demonstrates the ecological significance of this a priori channel classification, and indicates its potential utility in understanding spatial patterns of ecological dynamics, sample stratification for process-based studies, and reference

  11. Algorithmic derivation of functional renormalization group equations and Dyson-Schwinger equations

    NASA Astrophysics Data System (ADS)

    Huber, Markus Q.; Braun, Jens

    2012-06-01

    We present the Mathematica application DoFun which allows to derive Dyson-Schwinger equations and renormalization group flow equations for n-point functions in a simple manner. DoFun offers several tools which considerably simplify the derivation of these equations from a given physical action. We discuss the application of DoFun by means of two different types of quantum field theories, namely a bosonic O(N) theory and the Gross-Neveu model. Program summaryProgram title:DoFun Catalogue identifier: AELN_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AELN_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 35 506 No. of bytes in distributed program, including test data, etc.: 571 837 Distribution format: tar.gz Programming language: Mathematica 7 and higher Computer: PCs and workstations Operating system: All on which Mathematica is available (Windows, Unix, MacOS) Classification: 11.1, 11.4, 11.5, 11.6 Nature of problem: Derivation of functional renormalization group equations and Dyson-Schwinger equations from the action of a given theory. Solution method: Implementation of an algorithm to derive functional renormalization group and Dyson-Schwinger equations. Unusual features: The results can be plotted as Feynman diagrams in Mathematica. The output is compatible with the syntax of many other programs and is therefore suitable for further (algebraic) computations. Running time: Seconds to minutes

  12. Functional gene group analysis indicates no role for heterotrimeric G proteins in cognitive ability.

    PubMed

    Hill, W David; de Leeuw, Christiaan; Davies, Gail; Liewald, David Cherry McLachlan; Payton, Anthony; Craig, Leone C A; Whalley, Lawrence J; Horan, Mike; Ollier, William; Starr, John M; Pendleton, Neil; Posthuma, Danielle; Bates, Timothy C; Deary, Ian J

    2014-01-01

    Previous functional gene group analyses implicated common single nucleotide polymorphisms (SNPs) in heterotrimeric G protein coding genes as being associated with differences in human intelligence. Here, we sought to replicate this finding using five independent cohorts of older adults including current IQ and childhood IQ, and using both gene- and SNP-based analytic strategies. No significant associations were found between variation in heterotrimeric G protein genes and intelligence in any cohort at either of the two time points. These results indicate that, whereas G protein systems are important in cognition, common genetic variation in these genes is unlikely to be a substantial influence on human intelligence differences. PMID:24626473

  13. Importance of minor groove functional groups for the stability of DNA duplexes.

    PubMed

    Sun, Zhenhua; Chen, Dongli; Lan, Tao; McLaughlin, Larry W

    2002-11-01

    Eight oligonucleotide duplexes have been prepared with four pairs of selected complementary pairs of native/analogue heterocyclic bases incorporated at a selected test site. The base pairs vary in the nature of their functionality in the minor groove. Each pair has a minor groove purine amino group present or absent, and correspondingly has a minor grove pyrimidine carbonyl present or absent. Loss of duplex stability is most notable when the minor groove pyrimidine carbonyl is absent although in other respects normal Watson-Crick hydrogen bonding is maintained in these sequences. These differences in stability are discussed in terms of possible variations in minor groove hydration.

  14. Effects of Functional Groups and Sugar Composition of Quercetin Derivatives on Their Radical Scavenging Properties.

    PubMed

    Kato, Komei; Ninomiya, Masayuki; Tanaka, Kaori; Koketsu, Mamoru

    2016-07-22

    Quercetin derivatives are widespread in the plant kingdom and exhibit various biological actions. The aim of this study was to investigate the structure-activity relationships of quercetin derivatives, with a focus on the influence of functional groups and sugar composition on their antioxidant capacity. A series of quercetin derivatives were therefore prepared and assessed for their DPPH radical scavenging properties. Isoquercetin O-gallates were more potent radical scavengers than quercetin. The systematic analysis highlights the importance of the distribution of hydroxy substituents in isoquercetin O-gallates to their potency. PMID:27314621

  15. Nonperturbative renormalization group and momentum dependence of n-point functions. I

    SciTech Connect

    Blaizot, Jean-Paul; Mendez-Galain, Ramon; Wschebor, Nicolas

    2006-11-15

    We present an approximation scheme to solve the nonperturbative renormalization group equations and obtain the full momentum dependence of the n-point functions. It is based on an iterative procedure where, in a first step, an initial ansatz for the n-point functions is constructed by solving approximate flow equations derived from well motivated approximations. These approximations exploit the derivative expansion and the decoupling of high momentum modes. The method is applied to the O(N) model. In leading order, the self-energy is already accurate both in the perturbative and the scaling regimes. A stringent test is provided by the calculation of the shift {delta}T{sub c} in the transition temperature of the weakly repulsive Bose gas, a quantity which is particularly sensitive to all momentum scales. The leading order result is in agreement with lattice calculations, albeit with a theoretical uncertainty of about 25%.

  16. Functional groups in a single pteridosperm species: Variability and circumscription (Pennsylvanian, Nova Scotia, Canada)

    USGS Publications Warehouse

    Zodrow, E.L.; Mastalerz, Maria

    2007-01-01

    Multiple foliar specimens of the Late Pennsylvanian fossil pteridosperm [gymnosperm] Alethopteris zeilleri (Ragot) Wagner were collected from one restricted stratigraphical horizon in the Canadian Sydney Coalfield. Variability of functional-group distribution using FTIR technique was studied in compressions, adaxial versus abaxial cuticles, and in unseparated cuticles as a function of maceration time from 48 to 168??h. The results obtained document spectral variability that could be expected within specimens of one species. For example, CH2/CH3 and Al/ox ratios can differ by as much as 20% of the values. Moreover, the experiments performed confirm that by using a previously established maceration protocol, long maceration periods do not bias FTIR spectra in terms of oxygenation overprinting. The inference that this cuticle is robust, under the given diagenetic level, probably reflects a reassuring degree of chemical fidelity of the Pennsylvanian plant to support Carboniferous chemotaxonomic observations. ?? 2006 Elsevier B.V. All rights reserved.

  17. Functional correlations of spatial quantitative EEG and intelligences in a nonalphabetical language group.

    PubMed

    Yang, Chih-Chien; Yang, Chih-Chiang; Chaou, Wun-Tsong

    2005-01-01

    This study investigated any functional correlations between intelligences and spatially recorded quantitative electroencephalograms (QEEGs) in a nonalphabetical language group. Participants, between 6 and 8 years old, were sampled in a teaching hospital located at the central Taiwan region. The Chinese Wechsler Intelligence Scale for Children-III (WISC-III) intelligence test and quantitative electroencephalograph recording procedures were both administrated to collect data. Intelligences were divided into two categories, verbal and performance intelligences, for statistical investigations. Statistical analyses of the noncontaminated QEEG dataset investigated the differentiability of each frequency on a single cortical region and coherence between cortical regions. Low QEEG frequencies were found to have a significant correlation with intelligences on some cortical regions. Coherence between symmetric cortical regions was found to be an important factor in predicting intelligences. Results showed the feasibility of functional brain mapping in the particular language population.

  18. Functional renormalization group approach to the Yang-Lee edge singularity

    NASA Astrophysics Data System (ADS)

    An, X.; Mesterházy, D.; Stephanov, M. A.

    2016-07-01

    We determine the scaling properties of the Yang-Lee edge singularity as described by a one-component scalar field theory with imaginary cubic coupling, using the nonperturbative functional renormalization group in 3 ≤ d ≤ 6 Euclidean dimensions. We find very good agreement with high-temperature series data in d = 3 dimensions and compare our results to recent estimates of critical exponents obtained with the four-loop ɛ = 6 - d expansion and the conformal bootstrap. The relevance of operator insertions at the corresponding fixed point of the RG β functions is discussed and we estimate the error associated with O({partial}^4) truncations of the scale-dependent effective action.

  19. Chiral dynamics in a magnetic field from the functional renormalization group

    NASA Astrophysics Data System (ADS)

    Kamikado, Kazuhiko; Kanazawa, Takuya

    2014-03-01

    We investigate the quark-meson model in a magnetic field using the functional renormalization group equation beyond the local-potential approximation. Our truncation of the effective action involves anisotropic wave function renormalization for mesons, which allows us to investigate how the magnetic field distorts the propagation of neutral mesons. Solving the flow equation numerically, we find that the transverse velocity of mesons decreases with the magnetic field at all temperatures, which is most prominent at zero temperature. The meson screening masses and the pion decay constants are also computed. The constituent quark mass is found to increase with magnetic field at all temperatures, resulting in the crossover temperature that increases monotonically with the magnetic field. This tendency is consistent with most model calculations but not with the lattice simulation performed at the physical point. Our work suggests that the strong anisotropy of meson propagation may not be the fundamental origin of the inverse magnetic catalysis.

  20. Effects of the peer group on the development of social functioning and academic achievement: a longitudinal study in Chinese children.

    PubMed

    Chen, Xinyin; Chang, Lei; Liu, Hongyun; He, Yunfeng

    2008-01-01

    This longitudinal study examined, in a sample of Chinese children (initial mean ages = 9.5 and 12.7 years, N = 505), how the peer group contributed to social functioning and academic achievement and their associations. Data on informal peer groups, social functioning, and academic achievement were collected from multiple sources. Multilevel structural equation modeling revealed that group academic performance made direct contributions to children's social development. Group academic performance also moderated the individual-level relations between academic performance and later social functioning. Whereas high-achieving groups strengthened the positive relations between academic achievement and social competence, low-achieving groups facilitated the negative relations between academic achievement and social problems. The results indicate the significance of the peer group for social functioning from a developmental perspective.

  1. Intracellular localization of a group II chaperonin indicates a membrane-related function

    NASA Technical Reports Server (NTRS)

    Trent, Jonathan D.; Kagawa, Hiromi K.; Paavola, Chad D.; McMillan, R. Andrew; Howard, Jeanie; Jahnke, Linda; Lavin, Colleen; Embaye, Tsegereda; Henze, Christopher E.

    2003-01-01

    Chaperonins are protein complexes that are believed to function as part of a protein folding system in the cytoplasm of the cell. We observed, however, that the group II chaperonins known as rosettasomes in the hyperthermophilic archaeon Sulfolobus shibatae, are not cytoplasmic but membrane associated. This association was observed in cultures grown at 60 degrees C and 76 degrees C or heat-shocked at 85 degrees C by using immunofluorescence microscopy and in thick sections of rapidly frozen cells grown at 76 degrees C by using immunogold electron microscopy. We observed that increased abundance of rosettasomes after heat shock correlated with decreased membrane permeability at lethal temperature (92 degrees C). This change in permeability was not seen in cells heat-shocked in the presence of the amino acid analogue azetidine 2-carboxylic acid, indicating functional protein synthesis influences permeability. Azetidine experiments also indicated that observed heat-induced changes in lipid composition in S. shibatae could not account for changes in membrane permeability. Rosettasomes purified from cultures grown at 60 degrees C and 76 degrees C or heat-shocked at 85 degrees C bind to liposomes made from either the bipolar tetraether lipids of Sulfolobus or a variety of artificial lipid mixtures. The presence of rosettasomes did not significantly change the transition temperature of liposomes, as indicated by differential scanning calorimetry, or the proton permeability of liposomes, as indicated by pyranine fluorescence. We propose that these group II chaperonins function as a structural element in the natural membrane based on their intracellular location, the correlation between their functional abundance and membrane permeability, and their potential distribution on the membrane surface.

  2. Anthropogenic disturbances influencing ciliate functional feeding groups in impacted tropical streams.

    PubMed

    Segovia, Bianca Trevizan; Lansac-Toha, Fernando Miranda; de Meira, Bianca Ramos; Cabral, Adalgisa Fernanda; Lansac-Tôha, Fabio Amodêo; Velho, Luiz Felipe Machado

    2016-10-01

    Anthropogenic disturbances change the trophic structure of streams, ultimately affecting ecosystem functioning. We investigated the effects of human disturbances, mainly organic pollution, on ciliate functional feeding groups (FFG) in 10 tropical streams near agricultural and urban habitats, in the dry and rainy seasons. We hypothesised that the organic pollution would affect the ciliate composition and that the richness and abundance of ciliate FFG would be associated with different disturbances, such that an increase in the load of organic matter would result in an increase in the percentage of bacterivores ciliates, while streams with low organic matter concentration and wide canopy openness will determine a higher contribution of algivorous ciliates. Our results corroborate our hypothesis of an increased development of bacterivorous ciliates with increasing organic pollution, but only in the abundance of this FFG. Also, algivorous ciliates were found to be related to riparian vegetation clearing. Thus, ciliate FFG accurately reflected different anthropogenic disturbances, revealing a change in the trophic structure of the streams. In addition, we found that organic pollution can lead to both taxonomic and functional homogenization of the ciliate community, which implies serious consequences for ecosystem functioning.

  3. Control of Surface Functional Groups on Pertechntate Sorption on Activated Carbon

    SciTech Connect

    Y. Wang; H. Gao; R. Yeredla; H. Xu; M. Abrecht; G.D. Stasio

    2006-07-05

    {sup 99}Tc is highly soluble and poorly adsorbed by natural materials under oxidizing conditions, thus being of particular concern for radioactive waste disposal. Activated carbon can potentially be used as an adsorbent for removing Tc from aqueous solutions. We have tested six commercial activated carbon materials for their capabilities for sorption of pertechnetate (TcO{sub 4}{sup -}). The tested materials can be grouped into two distinct types: Type I materials have high sorption capabilities with the distribution coefficients (K{sub d}) varying from 9.5 x 10{sup 5} to 3.2 x 10{sup 3} mL/g as the pH changes from 4.5 to 9.5, whereas type II materials have relatively low sorption capabilities with K{sub d} remaining more or less constant (1.1 x 10{sup 3} - 1.8 x 10{sup 3} mL/g) over a similar pH range. The difference in sorption behavior between the two types of materials is attributed to the distribution of surface functional groups. The predominant surface groups are identified to be carboxylic and phenolic groups. The carboxylic group can be further divided into three subgroups A, B, and C in the order of increasing acidity. The high sorption capabilities of type I materials are found to be caused by the presence of a large fraction of carboxylic subgroups A and B, while the low sorption capabilities of type II materials are due to the exclusive presence of phenolic and carboxylic subgroup C. Therefore, the performance of activated carbon for removing TcO{sub 4}{sup -} can be improved by enhancing the formation of carboxylic subgroups A and B during material processing.

  4. Control of pertechnetate sorption on activated carbon by surface functional groups.

    PubMed

    Wang, Yifeng; Gao, Huizhen; Yeredla, Rakesh; Xu, Huifang; Abrecht, Mike

    2007-01-15

    The isotope 99Tc is highly soluble and poorly adsorbed by natural materials under oxidizing conditions, thus being of particular concern for radioactive waste disposal. Activated carbon can potentially be used as an adsorbent for removing Tc from aqueous solutions. We have tested six commercial activated carbon materials for their capabilities for sorption of pertechnetate (TcO4-). The tested materials can be grouped into two distinct types: Type I materials have high sorption capabilities with the distribution coefficients (Kd) varying from 9.5 x 10(5) to 3.2 x 10(3) ml/g as the pH changes from 4.5 to 9.5, whereas type II materials have relatively low sorption capabilities with Kd remaining more or less constant (1.1 x 10(3)-1.8 x 10(3) ml/g) over a similar pH range. The difference in sorption behavior between the two types of materials is attributed to the distribution of surface functional groups. The predominant surface groups are identified as carboxylic and phenolic groups. The carboxylic group can be further divided into three subgroups, A, B, and C, in the order of increasing acidity. The high sorption capabilities of type I materials are found to be caused by the presence of a large fraction of carboxylic subgroups A and B, while the low sorption capabilities of type II materials are due to the exclusive presence of phenolic and carboxylic subgroup C. Therefore, the performance of activated carbon for removing TcO4- can be improved by enhancing the formation of carboxylic subgroups A and B during materials processing.

  5. Trophic links between functional groups of arable plants and beetles are stable at a national scale.

    PubMed

    Brooks, David R; Storkey, Jonathan; Clark, Suzanne J; Firbank, Les G; Petit, Sandrine; Woiwod, Ian P

    2012-01-01

    1. There is an urgent need to accurately model how environmental change affects the wide-scale functioning of ecosystems, but advances are hindered by a lack of knowledge of how trophic levels are linked across space. It is unclear which theoretical approach to take to improve modelling of such interactions, but evidence is gathering that linking species responses to their functional traits can increase understanding of ecosystem dynamics. Currently, there are no quantitative studies testing how this approach might improve models of multiple, trophically interacting species, at wide spatial scales. 2. Arable weeds play a foundational role in linking food webs, providing resources for many taxa, including carabid beetles that feed on their seeds and weed-associated invertebrate prey. Here, we model associations between weeds and carabids across farmland in Great Britain (GB), to test the hypothesis that wide-scale trophic links between these groups are structured by their species functional traits. 3. A network of c. 250 arable fields, covering four crops and most lowland areas of GB, was sampled for weed, carabid and invertebrate taxa over 3 years. Data sets of these groups were closely matched in time and space, and each contained numerous species with a range of eco-physiological traits. The consistency of trophic linkages between multiple taxa sharing functional traits was tested within multivariate and log-linear models. 4. Robust links were established between the functional traits of taxa and their trophic interactions. Autumn-germinating, small-seeded weeds were associated with smaller, spring-breeding carabids, more specialised in seed feeding, whereas spring-germinating, large-seeded weeds were associated with a range of larger, autumn-breeding omnivorous carabids. These relationships were strong and dynamic, being independent of changes in invertebrate food resources and consistent across sample dates, crops and regions of GB. 5. We conclude that, in at

  6. Functional Identification of Ligands for a Catalytic Metal Ion in Group I Introns†

    PubMed Central

    Forconi, Marcello; Lee, Jihee; Lee, Jungjoon K.; Piccirilli, Joseph A.; Herschlag, Daniel

    2009-01-01

    Many enzymes use metal ions within their active sites to achieve enormous rate acceleration. Understanding how metal ions mediate catalysis requires elucidation of metal ion interactions with both the enzyme and the substrate(s). The three-dimensional arrangement determined by X-ray crystallography provides a powerful starting point for identifying ground state interactions, but only functional studies can establish and interrogate transition state interactions. The Tetrahymena group I ribozyme is a paradigm for the study of RNA catalysis, and previous work using atomic mutagenesis and quantitative analysis of metal ion rescue behavior identified catalytic metal ions making five contacts with the substrate atoms. Here, we have combined atomic mutagenesis with site-specific phosphorothioate substitutions in the ribozyme backbone to establish transition state ligands on the ribozyme for one of the catalytic metal ions, referred to as MA. We identified the pro-S P oxygen atoms at nucleotides C208, A304, and A306 as ground state ligands for Ma, verifying interactions suggested by the Azoarcus crystal structures. We further established that these interactions are present in the chemical transition state, a conclusion that requires functional studies, such as those carried out herein. Elucidating these active site connections is a crucial step toward an in-depth understanding of how specific structural features of the group I intron lead to catalysis. PMID:18517225

  7. Synthesis, algal inhibition activities and QSAR studies of novel gramine compounds containing ester functional groups

    NASA Astrophysics Data System (ADS)

    Li, Xia; Yu, Liangmin; Jiang, Xiaohui; Xia, Shuwei; Zhao, Haizhou

    2009-05-01

    2,5,6-Tribromo-1-methylgramine (TBG), isolated from bryozoan Zoobotryon pellucidum was shown to be very efficient in preventing recruitment of larval settlement. In order to improve the compatibility of TBG and its analogues with other ingredients in antifouling paints, structural modification of TBG was focused mainly on halogen substitution and N-substitution. Two halogen-substitute gramines and their derivatives which contain ester functional groups at N-position of gramines were synthesized. Algal inhibition activities of the synthesized compounds against algae Nitzschia closterium were evaluated and the Median Effective Concentration (EC50) range was 1.06-6.74 μg ml-1. Compounds that had a long chain ester group exhibited extremely high antifouling activity. Quantitive Structure Activity Relationship (QSAR) studies with multiple linear regression analysis were applied to find correlation between different calculated molecular descriptors and biological activity of the synthesized compounds. The results show that the toxicity (log (1/EC50)) is correlated well with the partition coefficient log P. Thus, these products have potential function as antifouling agents.

  8. Photoluminescence of oxygen vacancies and hydroxyl group surface functionalized SnO2 nanoparticles.

    PubMed

    Bonu, Venkataramana; Das, Arindam; Amirthapandian, S; Dhara, Sandip; Tyagi, Ashok Kumar

    2015-04-21

    We report, for the first time, the luminescence property of the hydroxyl group surface functionalized quantum dots (QDs) and nanoparticles (NPs) of SnO2 using low energy excitations of 2.54 eV (488 nm) and 2.42 eV (514.5 nm). This luminescence is in addition to generally observed luminescence from 'O' defects. The as-prepared SnO2 QDs are annealed at different temperatures under ambient conditions to create NPs with varying sizes. Subsequently, the average size of the NPs is calculated from the acoustic vibrations observed at low frequencies in the Raman spectra and by the transmission electron microscopy measurements. Detailed photoluminescence studies with 3.815 eV (325 nm) excitation reveal the nature of in-plane and bridging 'O' vacancies as well as adsorption and desorption occurring at different annealing temperatures. X-ray photoelectron spectroscopy studies also support this observation. The defect level related to the surface -OH functional groups shows a broad luminescence peak at around 1.96 eV in SnO2 NPs which is elaborated using temperature dependent studies. PMID:25774472

  9. Solubility and crystallizability: facile access to functionalized π-conjugated compounds with chlorendylimide protecting groups.

    PubMed

    Gebers, Jan; Rolland, Damien; Marty, Roman; Suàrez, Stéphane; Cervini, Luca; Scopelliti, Rosario; Brauer, Jan Cornelius; Frauenrath, Holger

    2015-01-19

    Functional π-conjugated molecules are relevant for the preparation of new organic electronic materials with improved performance. However, their synthesis is often rendered difficult by their inherently low solubility, and the permanent attachment of solubilizing groups may change the properties of the material. Here, we introduced the chlorendylimidyl moiety as a new temporary protecting group for the straightforward large-scale synthesis of protected quarter-, sexi-, octathiophene, and perylene bisimide diamine and dicarboxylic acid derivatives. The obtained chlorendylimides and chlorendylimidyl active esters were highly soluble in organic solvents, and optical spectroscopy confirmed the low tendency of the compounds to aggregate in solution. At the same time, they could be conveniently purified by recrystallization or precipitation. Single-crystal X-ray structures obtained for most compounds showed supramolecular motifs highlighting the role of the rigid, polychlorinated chlorendyl moieties in their crystallization. The obtained protected diamine and dicarboxylic acid derivatives were easily deprotected and converted into various amide-substituted oligothiophenes and perylene bisimides that are of interest as new functional materials for organic electronic thin film or nanowire devices. PMID:25427947

  10. Existence of ultrafine crevices and functional groups along the edge surfaces of graphitized thermal carbon black.

    PubMed

    Zeng, Yonghong; Do, D D; Nicholson, D

    2015-04-14

    Adsorption of different gases on graphitized thermal carbon black (GTCB) has been studied with a new molecular model to examine the consequences of micropore crevices and functional groups at the junctions between adjacent basal planes. Adsorption was simulated in the Grand Canonical Monte Carlo ensemble and the theoretical Henry constants were calculated by Monte Carlo volume integration over the Boltzmann factor of the solid-fluid potential. The simulation results are in good agreement with high-resolution experimental isotherms for argon on mineralogical graphite measured by Lopez-Gonzalez et al.1 From detailed inspection of the argon isotherms at extremely low coverages, we find two distinct Henry law regions, separated by a plateau (suggesting saturation of the stronger sites) that spans over a few decades of pressure. The first Henry law region is attributed to adsorption in the ultrafine crevices at the junctions between two adjacent basal planes, and the second region corresponds to adsorption on the basal plane, as confirmed by the theoretical Henry constant. The simulated isosteric heat and snapshots of molecular configurations show that argon adsorbs preferentially in the ultrafine crevices where there is a deep potential well due to overlap from the opposite pore walls. Similar behavior was found for other nonassociating fluids (Ar, N2, and CO2); however, for associating fluids (NH3 and H2O), the strong sites for adsorption and nucleation come from the combined effects of functional groups and ultrafine crevices, since the latter cannot alone account for the observed adsorption. PMID:25797845

  11. Assessing physiological responses of dune forest functional groups to changing water availability: from Tropics to Mediterranean.

    NASA Astrophysics Data System (ADS)

    Antunes, Cristina; Lo Cascio, Mauro; Correia, Otília; Vieira, Simone; Cruz Diaz Barradas, Maria; Zunzunegui, Maria; Ramos, Margarida; João Pereira, Maria; Máguas, Cristina

    2014-05-01

    Alterations in water availability are important to vegetation as can produce dramatic changes in plant communities, on physiological performance or survival of plant species. Particularly, groundwater lowering and surface water diversions will affect vulnerable coastal dune forests, ecosystems particularly sensitive to groundwater limitation. Reduction of water tables can prevent the plants from having access to one of their key water sources and inevitably affect groundwater-dependent species. The additional impact of drought due to climatic change on groundwater-dependent ecosystems has become of increasing concern since it aggravates groundwater reduction impacts with consequent uncertainties about how vegetation will respond over the short and long term. Sand dune plant communities encompass a diverse number of species that differ widely in root depth, tolerance to drought and capacity to shift between seasonal varying water sources. Plant functional groups may be affected by water distribution and availability differently. The high ecological diversity of sand dune forests, characterized by sandy soils, well or poorly drained, poor in nutrients and with different levels of salinity, can occur in different climatic regions of the globe. Such is the case of Tropical, Meso-mediterranean and Mediterranean areas, where future climate change is predicted to change water availability. Analyses of the relative natural abundances of stable isotopes of carbon (13C/12C) and oxygen (18O/16O) have been used across a wide range of scales, contributing to our understanding of plant ecology and interactions. This approach can show important temporal and spatial changes in utilization of different water sources by vegetation. Accordingly, the core idea of this work is to evaluate, along a climatic gradient, the responses and capacity of different coastal plant communities to adapt to changing water availability. This large-climatic-scale study, covering Brazil, Portugal and

  12. Response of herbivore functional groups to sequential perturbations in Moorea, French Polynesia

    NASA Astrophysics Data System (ADS)

    Han, Xueying; Adam, Thomas C.; Schmitt, Russell J.; Brooks, Andrew J.; Holbrook, Sally J.

    2016-09-01

    The reefs surrounding the island of Moorea, French Polynesia, experienced two large pulse perturbations between 2008 and 2010, an outbreak of the crown-of-thorns seastar ( Acanthaster planci) followed by a cyclone, that resulted in the reduction in live coral cover on the fore reef from ~40 to <5 %. Live coral cover in back reef and fringing reef habitats initially remained relatively stable, but began a gradual decline around 2010. We assessed the changes in the functional composition of the herbivorous fish community following the pulse perturbations and during the time of gradual coral decline on the back reef and fringing reef. Forty-nine species of herbivorous fishes quantified in yearly surveys between 2006 and 2014 were assigned to six functional groups: browser, detritivore, excavator, farmer, grazer/detritivore, and scraper. Non-metric multidimensional scaling analyses revealed that despite unique functional assemblages initially existing among the fringing reef, back reef, and fore reef habitats, the herbivorous fish communities in all three habitats responded in a qualitatively similar fashion to coral decline by moving toward functional communities characterized by an increased representation of excavators and scrapers. Island-wide scraper biomass increased by ~sevenfold in the post-disturbance time period, while excavator biomass increased by nearly threefold. The biomass of detritivores and grazers/detritivores also increased over the same time period, but to a much lesser degree, while the biomass of browsers and farmers remained essentially unchanged. Macroalgae remained a relatively minor space holder (<10 % cover) in lagoon habitats and on the fore reef through 2014, enabling recruitment of juvenile coral and initiating coral recovery on the fore reef. Results suggest that a functional community with a substantial biomass of herbivores and the capacity for the biomass of scrapers and excavators to increase rapidly in response to landscape

  13. Functional renormalization group approach to electronic structure calculations for systems without translational symmetry

    NASA Astrophysics Data System (ADS)

    Seiler, Christian; Evers, Ferdinand

    2016-10-01

    A formalism for electronic-structure calculations is presented that is based on the functional renormalization group (FRG). The traditional FRG has been formulated for systems that exhibit a translational symmetry with an associated Fermi surface, which can provide the organization principle for the renormalization group (RG) procedure. We here advance an alternative formulation, where the RG flow is organized in the energy-domain rather than in k space. This has the advantage that it can also be applied to inhomogeneous matter lacking a band structure, such as disordered metals or molecules. The energy-domain FRG (ɛ FRG) presented here accounts for Fermi-liquid corrections to quasiparticle energies and particle-hole excitations. It goes beyond the state of the art G W -BSE , because in ɛ FRG the Bethe-Salpeter equation (BSE) is solved in a self-consistent manner. An efficient implementation of the approach that has been tested against exact diagonalization calculations and calculations based on the density matrix renormalization group is presented. Similar to the conventional FRG, also the ɛ FRG is able to signalize the vicinity of an instability of the Fermi-liquid fixed point via runaway flow of the corresponding interaction vertex. Embarking upon this fact, in an application of ɛ FRG to the spinless disordered Hubbard model we calculate its phase boundary in the plane spanned by the interaction and disorder strength. Finally, an extension of the approach to finite temperatures and spin S =1 /2 is also given.

  14. A guide to the selection of switchable functional groups for CO2-switchable compounds.

    PubMed

    Alshamrani, A K; Vanderveen, J R; Jessop, P G

    2016-07-28

    Many CO2-responsive species, including many of the CO2-switchable surfactants, solvents, solutes, gels, colloids, and surfaces, rely on the ability of CO2 to lower the pH of water. Uncharged basic groups on the CO2-responsive species are therefore converted from a neutral state to a protonated cationic state (a bicarbonate salt), which causes dramatic and useful changes to the properties of the species. However, this switching process only works correctly if a basic group of appropriate basicity has been selected. This article presents a comprehensive guide to the selection of basic groups for CO2-switchable species for use in water. The appropriate basicity, as measured by the pKaH (the pKa of the protonated compound), is a function of the concentration of the switchable species, the temperature, the pressure of CO2, the presence or absence of an organic liquid phase, and the solubility of the neutral form of the compound. PMID:27373897

  15. Tailoring the mass distribution and functional group density of dimethylsiloxane-based films by thermal evaporation

    NASA Astrophysics Data System (ADS)

    Töpper, Tino; Lörcher, Samuel; Weiss, Florian; Müller, Bert

    2016-05-01

    The tailoring of molecular weight distribution and the functional group density of vinyl-terminated polydimethylsiloxane (PDMS) by molecular beam deposition is demonstrated herein. Thermally evaporated PDMS and its residue are characterized using gel permeation chromatography and nuclear magnetic resonance. Thermal fragmentation of vinyl groups occurs for evaporation temperatures above 487 K (214 °C). At a background pressure of 10-6 mbar, the maximum molecular weight distribution is adjusted from (700 ± 100) g/mol to (6100 ± 100) g/mol with a polydispersity index of 1.06 ± 0.02. The content of vinyl-termination per repeating unit of PDMS is tailored from (2.8 ± 0.2)% to (5.6 ± 0.1)%. Molecular weights of vinyl-terminated PDMS evaporated at temperatures above 388 K (115 °C) correspond to those attributed to trimethyl-terminated PDMS. Side groups of linear PDMS dominate intermolecular interactions and vapor pressure.

  16. Grafting of phosphorylcholine functional groups on polycarbonate urethane surface for resisting platelet adhesion.

    PubMed

    Gao, Bin; Feng, Yakai; Lu, Jian; Zhang, Li; Zhao, Miao; Shi, Changcan; Khan, Musammir; Guo, Jintang

    2013-07-01

    In order to improve the resistance of platelet adhesion on material surface, 2-methacryloyloxyethyl phosphorylcholine (MPC) was grafted onto polycarbonate urethane (PCU) surface via Michael reaction to create biomimetic structure. After introducing primary amine groups via coupling tris(2-aminoethyl)amine (TAEA) onto the polymer surface, the double bond of MPC reacted with the amino group to obtain MPC modified PCU. The modified surface was characterized by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The results verified that MPC was grafted onto PCU surface by Michael reaction method. The MPC grafted PCU surface had a low water contact angle and a high water uptake. This means that the hydrophilic PC functional groups improved the surface hydrophilicity significantly. In addition, surface morphology of MPC grafted PCU film was imaged by atomic force microscope (AFM). The results showed that the grafted surface was rougher than the blank PCU surface. In addition, platelet adhesion study was evaluated by scanning electron microscopy (SEM) observation. The PCU films after treated with platelet-rich plasma demonstrated that much fewer platelets adhered to the MPC-grafted PCU surface than to the blank PCU surface. The antithrombogenicity of the MPC-grafted PCU surface was determined by the activated partial thromboplastin time (APTT). The result suggested that the MPC modified PCU may have potential application as biomaterials in blood-contacting and some subcutaneously implanted devices.

  17. Image registration algorithm using Mexican hat function-based operator and grouped feature matching strategy.

    PubMed

    Jin, Feng; Feng, Dazheng

    2014-01-01

    Feature detection and matching are crucial for robust and reliable image registration. Although many methods have been developed, they commonly focus on only one class of image features. The methods that combine two or more classes of features are still novel and significant. In this work, methods for feature detection and matching are proposed. A Mexican hat function-based operator is used for image feature detection, including the local area detection and the feature point detection. For the local area detection, we use the Mexican hat operator for image filtering, and then the zero-crossing points are extracted and merged into the area borders. For the feature point detection, the Mexican hat operator is performed in scale space to get the key points. After the feature detection, an image registration is achieved by using the two classes of image features. The feature points are grouped according to a standardized region that contains correspondence to the local area, precise registration is achieved eventually by the grouped points. An image transformation matrix is estimated by the feature points in a region and then the best one is chosen through competition of a set of the transformation matrices. This strategy has been named the Grouped Sample Consensus (GCS). The GCS has also ability for removing the outliers effectively. The experimental results show that the proposed algorithm has high registration accuracy and small computational volume. PMID:24752223

  18. Effects of the Peer Group on the Development of Social Functioning and Academic Achievement: A Longitudinal Study in Chinese Children

    ERIC Educational Resources Information Center

    Chen, Xinyin; Chang, Lei; Liu, Hongyun; He, Yunfeng

    2008-01-01

    This longitudinal study examined, in a sample of Chinese children (initial mean ages = 9.5 and 12.7 years, N = 505), how the peer group contributed to social functioning and academic achievement and their associations. Data on informal peer groups, social functioning, and academic achievement were collected from multiple sources. Multilevel…

  19. Meta-selective C-H functionalization using a nitrile-based directing group and cleavable Si-tether.

    PubMed

    Lee, Sunggi; Lee, Hyelee; Tan, Kian L

    2013-12-18

    A nitrile-based template that enables meta-selective C-H bond functionalization was developed. The template is applicable to a range of substituted arenes and tolerates a variety of functional groups. The directing group uses a silicon atom for attachment, allowing for a facile introduction/deprotection strategy increasing the synthetic practicality of this template.

  20. In situ synchrotron IR study relating temperature and heating rate to surface functional group changes in biomass.

    PubMed

    Kirtania, Kawnish; Tanner, Joanne; Kabir, Kazi Bayzid; Rajendran, Sharmen; Bhattacharya, Sankar

    2014-01-01

    Three types of woody biomass were investigated under pyrolysis condition to observe the change in the surface functional groups by Fourier transform infrared (FTIR) technique with increasing temperature under two different (5 and 150°C/min) heating rates. The experiments were carried out in situ in the infrared microscopy beamline (IRM) of the Australian Synchrotron. The capability of the beamline made it possible to focus on single particles to obtain low noise measurements without mixing with KBr. At lower heating rate, the surface functional groups were completely removed by 550°C. In case of higher heating rate, a delay was observed in losing the functional groups. Even at a high temperature, significant number of functional groups was retained after the higher heating rate experiments. This implies that at considerably high heating rates typical of industrial reactors, more functional groups will remain on the surface.

  1. [The establishment, development and application of classification approach of freshwater phytoplankton based on the functional group: a review].

    PubMed

    Yang, Wen; Zhu, Jin-Yong; Lu, Kai-Hong; Wan, Li; Mao, Xiao-Hua

    2014-06-01

    Appropriate schemes for classification of freshwater phytoplankton are prerequisites and important tools for revealing phytoplanktonic succession and studying freshwater ecosystems. An alternative approach, functional group of freshwater phytoplankton, has been proposed and developed due to the deficiencies of Linnaean and molecular identification in ecological applications. The functional group of phytoplankton is a classification scheme based on autoecology. In this study, the theoretical basis and classification criterion of functional group (FG), morpho-functional group (MFG) and morphology-based functional group (MBFG) were summarized, as well as their merits and demerits. FG was considered as the optimal classification approach for the aquatic ecology research and aquatic environment evaluation. The application status of FG was introduced, with the evaluation standards and problems of two approaches to assess water quality on the basis of FG, index methods of Q and QR, being briefly discussed.

  2. Multistimulation group therapy in Alzheimer's disease promotes changes in brain functioning.

    PubMed

    Baglio, Francesca; Griffanti, Ludovica; Saibene, Francesca Lea; Ricci, Cristian; Alberoni, Margherita; Critelli, Raffaella; Villanelli, Fabiana; Fioravanti, Raffaella; Mantovani, Federica; D'amico, Alessandra; Cabinio, Monia; Preti, Maria Giulia; Nemni, Raffaello; Farina, Elisabetta

    2015-01-01

    Background. The growing social emergency represented by Alzheimer's disease (AD) and the lack of medical treatments able to modify the disease course have kindled the interest in nonpharmacological therapies. Objective. We introduced a novel nonpharmacological approach for people with AD (PWA) named Multidimensional Stimulation group Therapy (MST) to improve PWA condition in different disease domains: cognition, behavior, and motor functioning. Methods. Enrolling 60 PWA in a mild to moderate stage of the disease, we evaluated the efficacy of MST with a randomized-controlled study. Neuropsychological and neurobehavioral measures and functional magnetic resonance imaging (fMRI) data were considered as outcome measures. Results. The following significant intervention-related changes were observed: reduction in Neuropsychiatric Inventory scale score, improvement in language and memory subscales of Alzheimer's Disease Assessment Scale-Cognitive subscale, and increased fMRI activations in temporal brain areas, right insular cortex, and thalamus. Conclusions. Cognitive-behavioral and fMRI results support the notion that MST has significant effects in improving PWA cognitive-behavioral status by restoring neural functioning.

  3. IL-12 drives functional plasticity of human group 2 innate lymphoid cells.

    PubMed

    Lim, Ai Ing; Menegatti, Silvia; Bustamante, Jacinta; Le Bourhis, Lionel; Allez, Matthieu; Rogge, Lars; Casanova, Jean-Laurent; Yssel, Hans; Di Santo, James P

    2016-04-01

    Group 2 innate lymphoid cells (ILC2) include IL-5- and IL-13-producing CRTh2(+)CD127(+)cells that are implicated in early protective immunity at mucosal surfaces. Whereas functional plasticity has been demonstrated for both human and mouse ILC3 subsets that can reversibly give rise to IFN-γ-producing ILC1, plasticity of human or mouse ILC2 has not been shown. Here, we analyze the phenotypic and functional heterogeneity of human peripheral blood ILC2. Although subsets of human CRTh2(+)ILC2 differentially express CD117 (c-kit receptor), some ILC2 surface phenotypes are unstable and can be modulated in vitro. Surprisingly, human IL-13(+)ILC2 can acquire the capacity to produce IFN-γ, thereby generating plastic ILC2. ILC2 cultures demonstrated that IFN-γ(+)ILC2 clones could be derived and were stably associated with increased T-BET expression. The inductive mechanism for ILC2 plasticity was mapped to the IL-12-IL-12R signaling pathway and was confirmed through analysis of patients with Mendelian susceptibility to mycobacterial disease due to IL-12Rβ1 deficiencies that failed to generate plastic ILC2. We also detected IL-13(+)IFN-γ(+)ILC2 ex vivo in intestinal samples from Crohn's disease patients. These results demonstrate cytokine production plasticity for human ILC2 and further suggest that environmental cues can dictate ILC phenotype and function for these tissue-resident innate effector cells.

  4. Data-driven visualization and group analysis of multichannel EEG coherence with functional units.

    PubMed

    ten Caat, Michael; Maurits, Natasha M; Roerdink, Jos B T M

    2008-01-01

    A typical data-driven visualization of electroencephalography (EEG) coherence is a graph layout, with vertices representing electrodes and edges representing significant coherences between electrode signals. A drawback of this layout is its visual clutter for multichannel EEG. To reduce clutter, we define a functional unit (FU) as a data-driven region of interest (ROI). An FU is a spatially connected set of electrodes recording pairwise significantly coherent signals, represented in the coherence graph by a spatially connected clique. Earlier we presented two methods to detect FUs: a maximal clique based (MCB) method (time complexity O(3n/3), with n being the number of vertices) and a more efficient watershed based (WB) method (time complexity O (n2 log n)). To reduce the potential over-segmentation of the WB method, we introduce here an improved WB (IWB) method (time complexity O(n2 log n)). The IWB method merges basins representing FUs during the segmentation if they are spatially connected and if their union is a clique. The WB and IWB methods are both up to a factor of 100,000 faster than the MCB method for a typical multichannel setting with 128 EEG channels, thus making interactive visualization of multichannel EEG coherence possible. Results show that considering the MCB method as the gold standard, the difference between IWB and MCB FU maps is smaller than between WB and MCB FU maps. We also introduce two novel group maps for data-driven group analysis as extensions of the IWB method. First, the group mean coherence map preserves dominant features from a collection of individual FU maps. Second, the group FU size map visualizes the average FU size per electrode across a collection of individual FU maps. Finally, we employ an extensive case study to evaluate the IWB FU map and the two new group maps for data-driven group analysis. Results, in accordance with the conventional findings, indicate differences in EEG coherence between younger and older adults

  5. Expansion and Functional Divergence of AP2 Group Genes in Spermatophytes Determined by Molecular Evolution and Arabidopsis Mutant Analysis

    PubMed Central

    Wang, Pengkai; Cheng, Tielong; Lu, Mengzhu; Liu, Guangxin; Li, Meiping; Shi, Jisen; Lu, Ye; Laux, Thomas; Chen, Jinhui

    2016-01-01

    The APETALA2 (AP2) genes represent the AP2 group within a large group of DNA-binding proteins called AP2/EREBP. The AP2 gene is functional and necessary for flower development, stem cell maintenance, and seed development, whereas the other members of AP2 group redundantly affect flowering time. Here we study the phylogeny of AP2 group genes in spermatophytes. Spermatophyte AP2 group genes can be classified into AP2 and TOE types, six clades, and we found that the AP2 group homologs in gymnosperms belong to the AP2 type, whereas TOE types are absent, which indicates the AP2 type gene are more ancient and TOE type was split out of AP2 type and losing the major function. In Brassicaceae, the expansion of AP2 and TOE type lead to the gene number of AP2 group were up to six. Purifying selection appears to have been the primary driving force of spermatophyte AP2 group evolution, although positive selection occurred in the AP2 clade. The transition from exon to intron of AtAP2 in Arabidopsis mutant leads to the loss of gene function and the same situation was found in AtTOE2. Combining this evolutionary analysis and published research, the results suggest that typical AP2 group genes may first appear in gymnosperms and diverged in angiosperms, following expansion of group members and functional differentiation. In angiosperms, AP2 genes (AP2 clade) inherited key functions from ancestors and other genes of AP2 group lost most function but just remained flowering time controlling in gene formation. In this study, the phylogenies of AP2 group genes in spermatophytes was analyzed, which supported the evidence for the research of gene functional evolution of AP2 group. PMID:27703459

  6. Hydrated goethite (alpha-FeOOH) (100) interface structure: Ordered water and surface functional groups.

    SciTech Connect

    Ghose, S.K.; Waychunas, G.A.; Trainor, T.P.; Eng, P.J.

    2009-12-15

    Goethite({alpha}-FeOOH), an abundant and highly reactive iron oxyhydroxide mineral, has been the subject of numerous stud-ies of environmental interface reactivity. However, such studies have been hampered by the lack of experimental constraints on aqueous interface structure, and especially of the surface water molecular arrangements. Structural information of this type is crucial because reactivity is dictated by the nature of the surface functional groups and the structure or distribution of water and electrolyte at the solid-solution interface. In this study we have investigated the goethite(100) surface using surface diffraction techniques, and have determined the relaxed surface structure, the surface functional groups, and the three dimensional nature of two distinct sorbed water layers. The crystal truncation rod (CTR) results show that the interface structure consists of a double hydroxyl, double water terminated interface with significant atom relaxations. Further, the double hydroxyl terminated surface dominates with an 89% contribution having a chiral subdomain structure on the(100) cleavage faces. The proposed interface stoichiometry is ((H{sub 2}O)-(H{sub 2}O)-OH{sub 2}-OH-Fe-O-O-Fe-R) with two types of terminal hydroxyls; a bidentate (B-type) hydroxo group and a monodentate (A-type) aquo group. Using the bond-valence approach the protonation states of the terminal hydroxyls are predicted to be OH type (bidentate hydroxyl with oxygen coupled to two Fe{sup 3+} ions) and OH{sub 2} type (monodentate hydroxyl with oxygen tied to only one Fe{sup 3+}). A double layer three dimensional ordered water structure at the interface was determined from refinement of fits to the experimental data. Application of bond-valence constraints to the terminal hydroxyls with appropriate rotation of the water dipole moments allowed a plausible dipole orientation model as predicted. The structural results are discussed in terms of protonation and H-bonding at the interface

  7. Functional renormalization group analysis of the soft mode at the QCD critical point

    NASA Astrophysics Data System (ADS)

    Yokota, Takeru; Kunihiro, Teiji; Morita, Kenji

    2016-07-01

    We make an intensive investigation of the soft mode at the quantum chromodynamics (QCD) critical point on the basis of the functional renormalization group (FRG) method in the local potential approximation. We calculate the spectral functions ρ_{σ, π}(ω, p) in the scalar (σ) and pseudoscalar (π) channels beyond the random phase approximation in the quark-meson model. At finite baryon chemical potential μ with a finite quark mass, the baryon-number fluctuation is coupled to the scalar channel and the spectral function in the σ channel has a support not only in the time-like (ω > p) but also in the space-like (ω < p) regions, which correspond to the mesonic and the particle-hole phonon excitations, respectively. We find that the energy of the peak position of the latter becomes vanishingly small with the height being enhanced as the system approaches the QCD critical point, which is a manifestation of the fact that the phonon mode is the soft mode associated with the second-order transition at the QCD critical point, as has been suggested by some authors. Moreover, our extensive calculation of the spectral function in the (ω, p) plane enables us to see that the mesonic and phonon modes have the respective definite dispersion relations ω_{σ.ph}(p), and it turns out that ω_{σ}(p) crosses the light-cone line into the space-like region, and then eventually merges into the phonon mode as the system approaches the critical point more closely. This implies that the sigma-mesonic mode also becomes soft at the critical point. We also provide numerical stability conditions that are necessary for obtaining the accurate effective potential from the flow equation.

  8. Using multidimensional gas chromatography to group secondary organic aerosol species by functionality

    NASA Astrophysics Data System (ADS)

    Flores, Rosa M.; Doskey, Paul V.

    2014-10-01

    A carbon number-functionality grid (CNFG) for a complex mixture of secondary organic aerosol (SOA) precursors and oxidation products was developed from the theoretical retention index diagram of a multidimensional gas chromatographic (GC × 2GC) analysis of a mixture of SOA precursors and derivatized oxidation products. In the GC × 2GC analysis, comprehensive separation of the complex mixture was achieved by diverting the modulated effluent from a polar primary column into 2 polar secondary columns. Column stationary phases spanned the widest range of selectivity of commercially available GC analytic columns. In general, separation of the species by the polar primary column was by the number of carbon atoms in the molecule (when the homologous series of reference compounds was selected to have molecular volumes and functionalities similar to the target analytes) and the polar secondary columns provided additional separation according to functionality. An algebraic transformation of the Abraham solvation parameter model was used to estimate linear retention indices of solutes relative to elution of a homologous series of methyl diesters on the primary and secondary columns to develop the theoretical GC × 2GC retention diagram. Retention indices of many of the oxidation products of SOA precursors were estimated for derivatized forms of the solutes. The GC stationary phases selected for the primary column [(50%-Trifluoropropyl)-methylpolysiloxane] and secondary columns (90% Cyanopropyl Polysilphenylene-siloxane and Polyethylene Glycol in a Sol-Gel matrix) provided a theoretical separation of 33 SOA precursors and 98 derivatized oxidation products into 35 groups by molecular volume and functionality. Comprehensive analysis of extracts of vapor and aerosol samples containing semivolatile SOA precursors and oxidation products, respectively, is best accomplished by (1) separating the complex mixture of the vapor and underivatized aerosol extracts with a (50

  9. Functional gene groups are concentrated within chromosomes, among chromosomes and in the nuclear space of the human genome.

    PubMed

    Thévenin, Annelyse; Ein-Dor, Liat; Ozery-Flato, Michal; Shamir, Ron

    2014-09-01

    Genomes undergo changes in organization as a result of gene duplications, chromosomal rearrangements and local mutations, among other mechanisms. In contrast to prokaryotes, in which genes of a common function are often organized in operons and reside contiguously along the genome, most eukaryotes show much weaker clustering of genes by function, except for few concrete functional groups. We set out to check systematically if there is a relation between gene function and gene organization in the human genome. We test this question for three types of functional groups: pairs of interacting proteins, complexes and pathways. We find a significant concentration of functional groups both in terms of their distance within the same chromosome and in terms of their dispersal over several chromosomes. Moreover, using Hi-C contact map of the tendency of chromosomal segments to appear close in the 3D space of the nucleus, we show that members of the same functional group that reside on distinct chromosomes tend to co-localize in space. The result holds for all three types of functional groups that we tested. Hence, the human genome shows substantial concentration of functional groups within chromosomes and across chromosomes in space.

  10. Sum-rule Conserving Spectral Functions from the Numerical Renormalization Group

    NASA Astrophysics Data System (ADS)

    Weichselbaum, Andreas; von Delft, Jan

    2007-03-01

    We show how spectral functions for quantum impurity models, i.e. nanosystem embedded in fermionic or bosonic environment, can be calculated very accurately using a complete set of ``discarded'' numerical renormalization group (NRG) eigenstates, recently introduced by Anders and Schiller. The only approximation is to judiciously exploit energy scale separation. Our rigorous derivation avoids both the overcounting ambiguities and the single-shell approximation for the equilibrium density matrix prevalent in current methods including state of the art DM-NRG. The resulting procedure based on the full density matrix of the system (FDM-NRG) ensures that relevant sum rules hold rigorously and spectral features at energies below the temperature can be described accurately.

  11. Attachment, self-worth, and peer-group functioning in middle childhood.

    PubMed

    Booth-Laforce, Cathryn; Oh, Wonjung; Kim, Angel Hayoung; Rubin, Kenneth H; Rose-Krasnor, Linda; Burgess, Kim

    2006-12-01

    We evaluated links between peer-group functioning and indicators of attachment security in relation to both mother and father in middle childhood, among 73 10-year-olds (37 girls). Children's perceptions of security with both parents, coping styles with mother, and self-worth were assessed. Classmates, teachers, and mothers evaluated the participants' peer-related behavioral characteristics. Children's perceptions of security to both parents were related to others' appraisals of their social competence; perceptions of security to father were related to lower aggression. We did not find child gender effects, but children had higher security scores in relation to mother than to father. Self-worth perceptions mediated the relation between attachment and social competence.

  12. Functional group analysis in coal and on coal surfaces by NMR spectroscopy

    SciTech Connect

    Verkade, J.G.

    1989-10-01

    The reaction of Cl{ovr POCH{sub 2}CH{sub 2}O} (2) with moisture in pyridine extracts of Argonne standard coal samples has been found to give results comparable with the ASTM D3302 moisture analyses of these samples. Differences in the two sets of results are discussed. Some exceptionally large solvent effects on {sup 31}P chemical shifts of model compounds derivatized with 2 and 8 have been discovered. Initial experiments aimed at labile hydrogen functional group analysis of solid coal samples with 2 and Me{sub 2}N{ovr POCH{sub 2}CH{sub 2}O} (15) are described. 17 refs., 1 fig., 6 tabs.

  13. Physician perspectives on the structure and function of group practice HMOs.

    PubMed

    Kralewski, J E; Feldman, R; Gifford, G

    1992-01-01

    This article explores physicians' perspectives regarding how their HMOs function and their satisfaction with and loyalty to HMOs. Three HMOs were studied: a mature (28-year-old) staff model, a 16-year-old staff model, and a 13-year-old group model with both HMO and fee-for-service patients. While these HMOs were found to vary somewhat in terms of emphasis on patient care versus costs, methods used to control costs and degrees of centralization of decision making, they all received high overall satisfaction and loyalty scores. The staff model HMO with a more decentralized decision making structure received the highest satisfaction/loyalty score from its physicians. The degree to which physicians perceive the HMO to be effective and supportive and the use of educational programs and peer review to influence resource use were also found to be significantly related to physician satisfaction and loyalty.

  14. Attachment, self-worth, and peer-group functioning in middle childhood.

    PubMed

    Booth-Laforce, Cathryn; Oh, Wonjung; Kim, Angel Hayoung; Rubin, Kenneth H; Rose-Krasnor, Linda; Burgess, Kim

    2006-12-01

    We evaluated links between peer-group functioning and indicators of attachment security in relation to both mother and father in middle childhood, among 73 10-year-olds (37 girls). Children's perceptions of security with both parents, coping styles with mother, and self-worth were assessed. Classmates, teachers, and mothers evaluated the participants' peer-related behavioral characteristics. Children's perceptions of security to both parents were related to others' appraisals of their social competence; perceptions of security to father were related to lower aggression. We did not find child gender effects, but children had higher security scores in relation to mother than to father. Self-worth perceptions mediated the relation between attachment and social competence. PMID:17178610

  15. Effect of weak impurities on electronic properties of graphene: Functional renormalization-group analysis

    NASA Astrophysics Data System (ADS)

    Katanin, A.

    2013-12-01

    We consider an effect of weak impurities on the electronic properties of graphene within the functional renormalization-group approach. The energy dependences of the electronic self-energy and density of states near the neutrality point are discussed. Depending on the symmetry of the impurities, the electronic damping Γ and density of states ρ can deviate substantially from those given by the self-consistent Born approximation. We investigate the crossover from the results of the self-consistent Born approximation, which are valid far from the neutrality point to the strong-coupling (diffusive) regime near the neutrality point. For impurities, which are diagonal in both valley and sublattice indices, we obtain a finite density of states at the Fermi level with values which are much bigger than the result of the self-consistent Born approximation.

  16. Structural characterization and some coordinational aspects of tetrathiacalix[4]arenes functionalized by hydrazide groups

    NASA Astrophysics Data System (ADS)

    Podyachev, Sergey N.; Gubaidullin, Aidar T.; Syakaev, Victor V.; Sudakova, Svetlana N.; Masliy, Aleksey N.; Saifina, Alina F.; Burmakina, Nadezda Е.; Kuznetsov, Andrey M.; Shagidullin, Roald R.; Avvakumova, Ludmila V.; Konovalov, Alexander I.

    2010-04-01

    The structural peculiarities of tetrathiacalix[4]arenes with acetylhydrazide substitutes in cone and 1,3 -alternate conformations have been determined by means of X-ray analysis, IR and NMR spectroscopy. The structural and molecular modeling data were used in the interpretation of binding properties of calix[4]arene tetrahydrazides. The quantum-chemical calculations at the DFT level using the PBE exchange-correlation functional were performed for the complexation of 1,3 -alternate conformer of tetrathiacalix[4]arene with Ag + ion. It was shown that the removal of tert-butyl groups from tert-butyltetrathiacalix[4]arene platform facilitates a bis-ligand coordination of the metal ion and leads to a remarkable increase of Ag + extraction efficiency.

  17. O-Acetyl Oximes as Transformable Directing Groups for Pd-Catalyzed C–H Bond Functionalization

    PubMed Central

    Neufeldt, Sharon R.; Sanford, Melanie S.

    2010-01-01

    O-Acetyl oximes serve as effective directing groups for Pd-catalyzed sp2 and sp3 C–H functionalization reactions. The C–H functionalization products can be subsequently transformed into ortho- or β-functionalized ketones, alcohols, amines, and heterocycles. PMID:20041702

  18. Tree species from different functional groups respond differently to environmental changes during establishment.

    PubMed

    Barbosa, Eduardo R M; van Langevelde, Frank; Tomlinson, Kyle W; Carvalheiro, Luísa G; Kirkman, Kevin; de Bie, Steven; Prins, Herbert H T

    2014-04-01

    Savanna plant communities change considerably across time and space. The processes driving savanna plant species diversity, coexistence and turnover along environmental gradients are still unclear. Understanding how species respond differently to varying environmental conditions during the seedling stage, a critical stage for plant population dynamics, is needed to explain the current composition of plant communities and to enable us to predict their responses to future environmental changes. Here we investigate whether seedling response to changes in resource availability, and to competition with grass, varied between two functional groups of African savanna trees: species with small leaves, spines and N-fixing associations (fine-leaved species), and species with broad leaves, no spines, and lacking N-fixing associations (broad-leaved species). We show that while tree species were strongly suppressed by grass, the effect of resource availability on seedling performance varied considerably between the two functional groups. Nutrient inputs increased stem length only of broad-leaved species and only under an even watering treatment. Low light conditions benefited mostly broad-leaved species' growth. Savannas are susceptible to ongoing global environment changes. Our results suggest that an increase in woody cover is only likely to occur in savannas if grass cover is strongly suppressed (e.g. by fire or overgrazing). However, if woody cover does increase, broad-leaved species will benefit most from the resulting shaded environments, potentially leading to an expansion of the distribution of these species. Eutrophication and changes in rainfall patterns may also affect the balance between fine- and broad-leaved species. PMID:24337711

  19. Slug responses to grassland cutting and fertilizer application under plant functional group removal

    NASA Astrophysics Data System (ADS)

    Everwand, Georg; Scherber, Christoph; Tscharntke, Teja

    2013-04-01

    Current studies on trophic interactions in biodiversity experiments have largely relied on artificially sown gradients in plant diversity, but removal experiments with their more natural plant community composition are more realistic. Slugs are a major part of the invertebrate herbivore community, with some species being common pests in agriculture. We therefore investigated how strongly slugs are influenced by grassland management, plant biodiversity and composition. Here we analysed the effects of cutting frequency, fertilizer application and plant functional group composition on slug densities and their contribution to herbivory on Rumex acetosa in a removal experiment within a >100-year old grassland in Northern Germany. The experiment was laid out as a Latin rectangle with full factorial combinations of (i) plant functional group removal (3 levels) using herbicides, (ii) fertilizer application (2 levels) and (iii) cutting frequency (2 levels). The resulting 12 treatment combinations were replicated 6 times, resulting in 72 plots. We collected a total of 1020 individuals belonging to three species Arion distinctus (60.4% of individuals), Deroceras reticulatum (34.7%) and Arion lusitanicus (4.9%) using a cover board technique and additionally measured herbivore damage to R. acetosa. We found the highest slug abundance on plots with a low cutting frequency and high food resource availability (increased cover of forbs and taller vegetation). Fertilizer application had no significant effect on slug abundance, but caused higher herbivore damage to on R. acetosa, possibly as a result of increased tissue quality. The negative effect of higher cutting frequency on slug abundance was lowest in control plots with their naturally developed graminoid-forb communities (cutting reduced slug density by 6% in the control vs. 29% in herbicide plots). Our experiments therefore support the idea that more natural plant species compositions reduce the impact of disturbances (e

  20. An mTERF domain protein functions in group II intron splicing in maize chloroplasts.

    PubMed

    Hammani, Kamel; Barkan, Alice

    2014-04-01

    The mitochondrial transcription termination factor (mTERF) proteins are nucleic acid binding proteins characterized by degenerate helical repeats of ∼30 amino acids. Metazoan genomes encode a small family of mTERF proteins whose members influence mitochondrial gene expression and DNA replication. The mTERF family in higher plants consists of roughly 30 members, which localize to mitochondria or chloroplasts. Effects of several mTERF proteins on plant development and physiology have been described, but molecular functions of mTERF proteins in plants are unknown. We show that a maize mTERF protein, Zm-mTERF4, promotes the splicing of group II introns in chloroplasts. Zm-mTERF4 coimmunoprecipitates with many chloroplast introns and the splicing of some of these introns is disrupted even in hypomorphic Zm-mterf4 mutants. Furthermore, Zm-mTERF4 is found in high molecular weight complexes that include known chloroplast splicing factors. The splicing of two transfer RNAs (trnI-GAU and trnA-UGC) and one ribosomal protein messenger RNA (rpl2) is particularly sensitive to the loss of Zm-mTERF4, accounting for the loss of plastid ribosomes in Zm-mTERF4 mutants. These findings extend the known functional repertoire of the mTERF family to include group II intron splicing and suggest that a conserved role in chloroplast RNA splicing underlies the physiological defects described for mutations in BSM/Rugosa2, the Zm-mTERF4 ortholog in Arabidopsis.

  1. Evidence for Functional Groupings of Vibrissae across the Rodent Mystacial Pad.

    PubMed

    Hobbs, Jennifer A; Towal, R Blythe; Hartmann, Mitra J Z

    2016-01-01

    During natural exploration, rats exhibit two particularly conspicuous vibrissal-mediated behaviors: they follow along walls, and "dab" their snouts on the ground at frequencies related to the whisking cycle. In general, the walls and ground may be located at any distance from, and at any orientation relative to, the rat's head, which raises the question of how the rat might determine the position and orientation of these surfaces. Previous studies have compellingly demonstrated that rats can accurately determine the horizontal angle at which a vibrissa first touches an object, and we therefore asked whether this parameter could provide the rat with information about the pitch, distance, and yaw of a surface relative to its head. We used a three-dimensional model of the whisker array to construct mappings between the horizontal angle of contact of each vibrissa and every possible (pitch, distance, and yaw) configuration of the head relative to a flat surface. The mappings revealed striking differences in the patterns of contact for vibrissae in different regions of the array. The exterior (A, D, E) rows provide information about the relative pitch of the surface regardless of distance. The interior (B, C) rows provide distance cues regardless of head pitch. Yaw is linearly correlated with the difference between the number of right and left whiskers touching the surface. Compared to the long reaches that whiskers can make to the side and below the rat, the reachable distance in front of the rat's nose is relatively small. We confirmed key predictions of these functional groupings in a behavioral experiment that monitored the contact patterns that the vibrissae made with a flat vertical surface. These results suggest that vibrissae in different regions of the array are not interchangeable sensors, but rather functionally grouped to acquire particular types of information about the environment. PMID:26745501

  2. Evidence for Functional Groupings of Vibrissae across the Rodent Mystacial Pad

    PubMed Central

    Hobbs, Jennifer A.; Towal, R. Blythe; Hartmann, Mitra J. Z.

    2016-01-01

    During natural exploration, rats exhibit two particularly conspicuous vibrissal-mediated behaviors: they follow along walls, and “dab” their snouts on the ground at frequencies related to the whisking cycle. In general, the walls and ground may be located at any distance from, and at any orientation relative to, the rat’s head, which raises the question of how the rat might determine the position and orientation of these surfaces. Previous studies have compellingly demonstrated that rats can accurately determine the horizontal angle at which a vibrissa first touches an object, and we therefore asked whether this parameter could provide the rat with information about the pitch, distance, and yaw of a surface relative to its head. We used a three-dimensional model of the whisker array to construct mappings between the horizontal angle of contact of each vibrissa and every possible (pitch, distance, and yaw) configuration of the head relative to a flat surface. The mappings revealed striking differences in the patterns of contact for vibrissae in different regions of the array. The exterior (A, D, E) rows provide information about the relative pitch of the surface regardless of distance. The interior (B, C) rows provide distance cues regardless of head pitch. Yaw is linearly correlated with the difference between the number of right and left whiskers touching the surface. Compared to the long reaches that whiskers can make to the side and below the rat, the reachable distance in front of the rat’s nose is relatively small. We confirmed key predictions of these functional groupings in a behavioral experiment that monitored the contact patterns that the vibrissae made with a flat vertical surface. These results suggest that vibrissae in different regions of the array are not interchangeable sensors, but rather functionally grouped to acquire particular types of information about the environment. PMID:26745501

  3. Delineating native and invasive plant functional groups in shrub-steppe vegetation using bidirectional reflectance

    NASA Astrophysics Data System (ADS)

    Naupari, Javier A.; Vierling, Lee A.; Eitel, Jan U. H.

    2013-01-01

    Delineating invasive and native plant types using remote sensing is important for managing rangelands. Remote characterization of rangeland vegetation often utilizes only the nadir view, which can be complicated by background soil reflectance. We therefore collected bidirectional radiometric measurements on a shrub-steppe vegetated landscape throughout the mid- to late-growing season to: (1) quantify the BRFs of four rangeland vegetation functional groups (native shrub, native grasses, invasive annual grasses, and forbs), and (2) examine ways in which bidirectional reflectance values may help delineate native and invasive vegetation types. We found that the invasive grass medusahead rye (Taeniatherum caput-medusae [L.] Nevski) could be discriminated from other vegetation types at nadir and across four forward-viewing zenith angles because this species exhibited structural changes when leaf orientation changed from erectophile to planophile during and after the filling of seedheads. We also confirmed that native shrubs exhibited the highest anisotropy in all wavebands, as the relatively complex structure of the shrub canopy and concomitant shadowing greatly affected values of normalized difference vegetation index across all view angles. In order to delineate rangeland vegetation types at coarser scales, further study is needed to quantify the spectral angular signatures of these plant groups using satellite-based images.

  4. Comprehensive study of mesoporous carbon functionalized with carboxylate groups and magnetic nanoparticles as a promising adsorbent.

    PubMed

    Chi, Yue; Geng, Wangchang; Zhao, Liang; Yan, Xiao; Yuan, Qing; Li, Nan; Li, Xiaotian

    2012-03-01

    Highly ordered mesoporous carbon functionalized with carboxylate groups and magnetic nanoparticles has been successfully synthesized. By oxidative treatment using (NH(4))(2)S(2)O(8) and H(2)SO(4) mixed solution, numerous hydrophilic groups were created in the mesopores without destroying the ordered mesostructure of CMK-3. Through the in situ reduction in Fe(3+), magnetic nanoparticles were successfully introduced into the mesopores, resulting in the multifunctional mesoporous carbon Fe-CMK-3. The obtained hybrid carbon material possesses ordered mesostructure, high Brunauer-Emmett-Teller (BET) surface area up to 1013 m(2)/g, large pore volume of about 1.16 cm(3)/g, carboxylic surface, and excellent magnetic property. When used as an adsorbent, Fe-CMK-3 exhibits excellent performances for removing toxic organic compounds from waster-water, with a high adsorption capacity, an extremely rapid adsorption rate, and an easy magnetically separable process. In the case of requiring emergency removal of large amount of organic pollutants in aqueous, the hybrid carbon adsorbent would be an ideal choice.

  5. Regulation of metabolic health and adipose tissue function by group 2 innate lymphoid cells.

    PubMed

    Cautivo, Kelly M; Molofsky, Ari B

    2016-06-01

    Adipose tissue (AT) is home to an abundance of immune cells. With chronic obesity, inflammatory immune cells accumulate and promote insulin resistance and the progression to type 2 diabetes mellitus. In contrast, recent studies have highlighted the regulation and function of immune cells in lean, healthy AT, including those associated with type 2 or "allergic" immunity. Although traditionally activated by infection with multicellular helminthes, AT type 2 immunity is active independently of infection, and promotes tissue homeostasis, AT "browning," and systemic insulin sensitivity, protecting against obesity-induced metabolic dysfunction and type 2 diabetes mellitus. In particular, group 2 innate lymphoid cells (ILC2s) are integral regulators of AT type 2 immunity, producing the cytokines interleukin-5 and IL-13, promoting eosinophils and alternatively activated macrophages, and cooperating with and promoting AT regulatory T (Treg) cells. In this review, we focus on the recent developments in our understanding of group 2 innate lymphoid cell cells and type 2 immunity in AT metabolism and homeostasis.

  6. Neurophysiological marker of inhibition distinguishes language groups on a non-linguistic executive function test.

    PubMed

    Fernandez, M; Tartar, J L; Padron, D; Acosta, J

    2013-12-01

    Successful interaction with the environment depends on flexible behaviors which require shifting attention, inhibiting primed responses, ignoring distracting information, and withholding motor responses. These abilities, termed executive function (EF), are believed to be mediated by inhibitory processes in the frontal lobes. Superior performance on EF tests (i.e., faster reaction times (RT), and fewer errors) has been shown in bilinguals compared to monolingual speakers. However, findings are inconsistent, and no study has directly linked this bilingual advantage to frontal lobe inhibitory processes. To clarify this uncertainty, we concomitantly tested neural inhibitory processes and behavioral responses on an EF test in bilinguals and monolinguals. Specifically, we compared English monolinguals (N=15) to Spanish/English bilinguals (N=13) on event-related brain potentials (ERP) during a non-linguistic, auditory Go/NoGo task, a task linked to non-motor, cognitive inhibition in monolinguals. Participants responded with a button press on trials in which target tone-pairs (Go trials) were presented and withheld their responses on non-target trials (NoGo trials). Results revealed significantly greater inhibition (i.e., greater mean N2 amplitude) in bilinguals compared to monolinguals during NoGo trials even though both groups performed the task equally well (i.e., withheld a motor response). On Go trials where participants pressed a response button, neither ERPs nor RT distinguished the groups. Additionally, scores on a second language proficiency test (i.e., English in our bilingual group) were positively correlated with N2 amplitude. These findings are the first to directly link this bilingual advantage to a neural correlate of inhibition and to reveal that inhibition in bilinguals is moderated by second language proficiency. Results are discussed in the context of plasticity, and we propose that evaluating bilinguals at varying levels of second-language proficiency

  7. Chemical Assignment of Symmetry-Adapted Perturbation Theory Interaction Energy Components: The Functional-Group SAPT Partition.

    PubMed

    Parrish, Robert M; Parker, Trent M; Sherrill, C David

    2014-10-14

    Recently, we introduced an effective atom-pairwise partition of the many-body symmetry-adapted perturbation theory (SAPT) interaction energy decomposition, producing a method known as atomic SAPT (A-SAPT) [Parrish, R. M.; Sherrill, C. D. J. Chem. Phys. 2014, 141, 044115]. A-SAPT provides ab initio atom-pair potentials for force field development and also automatic visualizations of the spatial contributions of noncovalent interactions, but often has difficulty producing chemically useful partitions of the electrostatic energy, due to the buildup of oscillating partial charges on adjacent functional groups. In this work, we substitute chemical functional groups in place of atoms as the relevant local quasiparticles in the partition, resulting in a functional-group-pairwise partition denoted as functional-group SAPT (F-SAPT). F-SAPT assigns integral sets of local occupied electronic orbitals and protons to chemical functional groups and linking σ bonds. Link-bond contributions can be further assigned to chemical functional groups to simplify the analysis. This approach yields a SAPT partition between pairs of functional groups with integral charge (usually neutral), preventing oscillations in the electrostatic partition. F-SAPT qualitatively matches chemical intuition and the cut-and-cap fragmentation technique but additionally yields the quantitative many-body SAPT interaction energy. The conceptual simplicity, chemical utility, and computational efficiency of F-SAPT is demonstrated in the context of phenol dimer, proflavine(+)-DNA intercalation, and a cucurbituril host-guest inclusion complex. PMID:26588139

  8. Construction of functional group reactivity database under various reaction conditions automatically extracted from reaction database in a synthesis design system.

    PubMed

    Tanaka, Akio; Okamoto, Hideho; Bersohn, Malcolm

    2010-03-22

    To be able to estimate the reactivity of functional groups under certain reaction conditions, we have stored three types of data: (1) data of change or destruction of the functional groups by the conditions of the reaction conditions; (2) data showing no influence of the reaction conditions on the functional groups; and (3) data showing the relative reactivity of two functional groups in the presence of certain reaction conditions. These three types of data, considered together, form entities that are referenced as "interaction data". These interaction data are used in a synthesis design system called SYNSUP. A new module in our system has been constructed that automatically generates interaction data from the reaction databases. From 15 265 reactions in the database, our program selected 2763 useful reactions with yields of > or =90% and one functional group change. From these useful reactions, data regarding 465 interferences, 815 cases of inert functional groups (under the reaction conditions), and 62 relative rate data could be extracted. In addition, with the use of multiple relative rate datasets, the reactivity of more than two functional groups could be deduced.

  9. Chemical Assignment of Symmetry-Adapted Perturbation Theory Interaction Energy Components: The Functional-Group SAPT Partition.

    PubMed

    Parrish, Robert M; Parker, Trent M; Sherrill, C David

    2014-10-14

    Recently, we introduced an effective atom-pairwise partition of the many-body symmetry-adapted perturbation theory (SAPT) interaction energy decomposition, producing a method known as atomic SAPT (A-SAPT) [Parrish, R. M.; Sherrill, C. D. J. Chem. Phys. 2014, 141, 044115]. A-SAPT provides ab initio atom-pair potentials for force field development and also automatic visualizations of the spatial contributions of noncovalent interactions, but often has difficulty producing chemically useful partitions of the electrostatic energy, due to the buildup of oscillating partial charges on adjacent functional groups. In this work, we substitute chemical functional groups in place of atoms as the relevant local quasiparticles in the partition, resulting in a functional-group-pairwise partition denoted as functional-group SAPT (F-SAPT). F-SAPT assigns integral sets of local occupied electronic orbitals and protons to chemical functional groups and linking σ bonds. Link-bond contributions can be further assigned to chemical functional groups to simplify the analysis. This approach yields a SAPT partition between pairs of functional groups with integral charge (usually neutral), preventing oscillations in the electrostatic partition. F-SAPT qualitatively matches chemical intuition and the cut-and-cap fragmentation technique but additionally yields the quantitative many-body SAPT interaction energy. The conceptual simplicity, chemical utility, and computational efficiency of F-SAPT is demonstrated in the context of phenol dimer, proflavine(+)-DNA intercalation, and a cucurbituril host-guest inclusion complex.

  10. Determination of HDV ribozyme N(-1) nucleobase and functional group specificity using internal competition kinetics

    PubMed Central

    Kellerman, Daniel L; Simmons, Kandice S; Pedraza, Mayra; Piccirilli, Joseph A; York, Darrin M; Harris, Michael E

    2015-01-01

    Biological catalysis involves interactions distant from the site of chemistry that can position the substrate for reaction. Catalysis of RNA 2′-O-transphosphorylation by the HDV ribozyme is sensitive to the identity of the N(-1) nucleotide flanking the reactive phosphoryl group. However, the interactions that affect the conformation of this position, and in turn the 2′O nucleophile, are unclear. Here, we describe the application of multiple substrate internal competition kinetic analyses to understand how the N(-1) nucleobase contributes to HDV catalysis, and to test the utility of this approach for RNA structure-function studies. Internal competition reactions containing all four substrate sequence variants at the N(-1) position in reactions using ribozyme active site mutations at A77 and A78 were used to test a proposed basepairing interaction. Mutants A78U, A78G and A79G retain significant catalytic activity, but do not alter the specificity for the N(-1) nucleobase. Effects of nucleobase analog substitutions at N(-1) indicate that U is preferred due to the ability to donate an H-bond in the Watson-Crick face and avoid minor groove steric clash. The results provide information essential for evaluating models of the HDV active site, and illustrate multiple-substrate kinetic analyses as a practical approach for characterizing structure-function relationships in RNA reactions. PMID:25937290

  11. Homogeneous Ziegler-Natta polymerization of functionalized monomers catalyzed by cationic group IV metallocenes

    SciTech Connect

    Kesti, M.R.; Coates, G.W.; Waymouth, R.M.

    1992-11-18

    Ziegler-Natta catalysts are remarkable in their ability to polymerize {alpha}-olefins to high molecular weight, stereoregular polyolefins. One of the major limitations of conventional Ziegler-Natta catalysts is their intolerance to Lewis bases; catalysts based on titanium halides and alkylaluminum cocatalysts are poisoned by most types of monomers containing ethers, esters, amines, and carboxylic acids. The absence of functionality in hydrocarbon polymers seriously affects their adhesive properties, affinity for dyes, permeability, and compatibility with more polar polymers. Previous attempts to polymerize sterically hindered amines, esters and amides, alkyl halides, and carboxylic acids using catalysts derived from TiCl{sub 3} and AlR{sub 3-n}Cl{sub n} have achieved limited success due to the severe loss of catalytic activity in the presence of these monomers. This work reports that cationic, group four metallocenes are active catalysts for the homo-polymerization of {alpha}-olefins containing silyl-protected alcohols and tertiary amines. Employing different monomers and conditions, a table shows the starting monomer, reaction time and temperature, and spectroscopic analysis of the end products. A major advanatage of these metallocene-based catalysts is that the ligand system can be modified to proved the optimal combination of catalystic activity, stereospecificity, and tolerance to functionality. 32 refs., 1 tab.

  12. Longitudinal Distribution of the Functional Feeding Groups of Aquatic Insects in Streams of the Brazilian Cerrado Savanna.

    PubMed

    Brasil, L S; Juen, L; Batista, J D; Pavan, M G; Cabette, H S R

    2014-10-01

    We demonstrate that the distribution of the functional feeding groups of aquatic insects is related to hierarchical patch dynamics. Patches are sites with unique environmental and functional characteristics that are discontinuously distributed in time and space within a lotic system. This distribution predicts that the occurrence of species will be based predominantly on their environmental requirements. We sampled three streams within the same drainage basin in the Brazilian Cerrado savanna, focusing on waterfalls and associated habitats (upstream, downstream), representing different functional zones. We collected 2,636 specimens representing six functional feeding groups (FFGs): brushers, collector-gatherers, collector-filterers, shredders, predators, and scrapers. The frequency of occurrence of these groups varied significantly among environments. This variation appeared to be related to the distinct characteristics of the different habitat patches, which led us to infer that the hierarchical patch dynamics model can best explain the distribution of functional feeding groups in minor lotic environments, such as waterfalls. PMID:27193952

  13. Longitudinal Distribution of the Functional Feeding Groups of Aquatic Insects in Streams of the Brazilian Cerrado Savanna.

    PubMed

    Brasil, L S; Juen, L; Batista, J D; Pavan, M G; Cabette, H S R

    2014-10-01

    We demonstrate that the distribution of the functional feeding groups of aquatic insects is related to hierarchical patch dynamics. Patches are sites with unique environmental and functional characteristics that are discontinuously distributed in time and space within a lotic system. This distribution predicts that the occurrence of species will be based predominantly on their environmental requirements. We sampled three streams within the same drainage basin in the Brazilian Cerrado savanna, focusing on waterfalls and associated habitats (upstream, downstream), representing different functional zones. We collected 2,636 specimens representing six functional feeding groups (FFGs): brushers, collector-gatherers, collector-filterers, shredders, predators, and scrapers. The frequency of occurrence of these groups varied significantly among environments. This variation appeared to be related to the distinct characteristics of the different habitat patches, which led us to infer that the hierarchical patch dynamics model can best explain the distribution of functional feeding groups in minor lotic environments, such as waterfalls.

  14. Soil surface protection by Biocrusts: effects of functional groups on textural properties

    NASA Astrophysics Data System (ADS)

    Concostrina-Zubiri, Laura; Huber-Sannwald, Elisabeth; Martínez, Isabel; Flores Flores, José Luis; Escudero, Adrián

    2015-04-01

    In drylands, where vegetation cover is commonly scarce, soil surface is prone to wind and water soil erosion, with the subsequent loss of topsoil structure and chemical properties. These processes are even more pronounced in ecosystems subjected to extra erosive forces, such as grasslands and rangelands that support livestock production. However, some of the physiological and functional traits of biocrusts (i.e., complex association of cyanobacteria, lichens, mosses, fungi and soil particles) make them ideal to resist in disturbed environments and at the same time to protect soil surface from mechanical perturbations. In particular, the filaments and exudates of soil cyanobacteria and the rhizines of lichen can bind together soil particles, forming soil aggregates at the soil surface and thus enhancing soil stability. Also, they act as "biological covers" that preserve the most vulnerable soil layer from wind and runoff erosion and raindrop impact, maintaining soil structure and composition. In this work, we evaluated soil textural properties and organic matter content under different functional groups of biocrusts (i.e., cyanobacteria crust, 3 lichen species, 1 moss species) and in bare soil. In order to assess the impact of livestock trampling on soil properties and on Biocrust function, we sampled three sites conforming a disturbance gradient (low, medium and high impact sites) and a long-term livestock exclusion as control site. We found that the presence of biocrusts had little effects on soil textural properties and organic matter content in the control site, while noticeable differences were found between bare soil and soil under biocrusts (e.g., up to 16-37% higher clay content, compared to bare soil and up to 10% higher organic matter content). In addition, we found that depending on morphological traits and grazing regime, the effects of biocrusts changed along the gradient. For example, soil under the lichen Diploschistes diacapsis, with thick thallus

  15. Woody plant encroachment into grasslands: spatial patterns of functional group distribution and community development.

    PubMed

    Liu, Feng; Archer, Steven R; Gelwick, Frances; Bai, Edith; Boutton, Thomas W; Wu, Xinyuan Ben

    2013-01-01

    Woody plant encroachment into grasslands has been globally widespread. The woody species invading grasslands represent a variety of contrasting plant functional groups and growth forms. Are some woody plant functional types (PFTs) better suited to invade grasslands than others? To what extent do local patterns of distribution and abundance of woody PFTs invading grasslands reflect intrinsic topoedaphic properties versus plant-induced changes in soil properties? We addressed these questions in the Southern Great Plains, United States at a subtropical grassland known to have been encroached upon by woody species over the past 50-100 years. A total of 20 woody species (9 tree-statured; 11 shrub-statured) were encountered along a transect extending from an upland into a playa basin. About half of the encroaching woody plants were potential N2-fixers (55% of species), but they contributed only 7% to 16 % of the total basal area. Most species and the PFTs they represent were ubiquitously distributed along the topoedaphic gradient, but with varying abundances. Overstory-understory comparisons suggest that while future species composition of these woody communities is likely to change, PFT composition is not. Canonical correspondence analysis (CCA) ordination and variance partitioning (Partial CCA) indicated that woody species and PFT composition in developing woody communities was primarily influenced by intrinsic landscape location variables (e.g., soil texture) and secondarily by plant-induced changes in soil organic carbon and total nitrogen content. The ubiquitous distribution of species and PFTs suggests that woody plants are generally well-suited to a broad range of grassland topoedaphic settings. However, here we only examined categorical and non-quantitative functional traits. Although intrinsic soil properties exerted more control over the floristics of grassland-to-woodland succession did plant modifications of soil carbon and nitrogen concentrations, the latter

  16. Anion Binding in Metal-Organic Frameworks Functionalized with Urea Hydrogen-Bonding Groups

    SciTech Connect

    Custelcean, Radu; Moyer, Bruce A; Bryantsev, Vyacheslav S.; Hay, Benjamin P.

    2006-01-01

    A series of metal-organic frameworks (MOFs) functionalized with urea hydrogen-bonding groups has been synthesized and structurally analyzed by single-crystal X-ray diffraction to evaluate the efficacy of anion coordination by urea within the structural constraints of the MOFs. We found that urea-based functionalities may be used for anion binding within metal-organic frameworks when the tendency for urea{hor_ellipsis}urea self-association is decreased by strengthening the intramolecular CH{hor_ellipsis}O hydrogen bonding of N-phenyl substituents to the carbonyl oxygen atom. Theoretical calculations indicate that N,N'-bis(m-pyridyl)urea (BPU) and N,N'-bis(m-cyanophenyl)urea (BCPU) should have enhanced hydrogen-bonding donor abilities toward anions and decreased tendencies to self-associate into hydrogen-bonded tapes compared to other disubstituted ureas. Accordingly, BPU and BCPU were incorporated in MOFs as linkers through coordination of various Zn, Cu, and Ag transition metal salts, including Zn(ClO{sub 4}){sub 2}, ZnSO{sub 4}, Cu(NO{sub 3}){sub 2}, Cu(CF{sub 3}SO{sub 3}){sub 2}, AgNO{sub 3}, and AgSO{sub 3}CH{sub 3}. Structural analysis by single-crystal X-ray diffraction showed that these linkers are versatile anion binders, capable of chelate hydrogen bonding to all of the oxoanions explored. Anion coordination by the urea functionalities was found to successfully compete with urea self-association in all cases except for that of charge-diffuse perchlorate.

  17. Functional group biodiversity in Eastern Boundary Upwelling Ecosystems questions the wasp-waist trophic structure

    NASA Astrophysics Data System (ADS)

    Fréon, Pierre; Arístegui, Javier; Bertrand, Arnaud; Crawford, Robert J. M.; Field, John C.; Gibbons, Mark J.; Tam, Jorge; Hutchings, Larry; Masski, Hicham; Mullon, Christian; Ramdani, Mohamed; Seret, Bernard; Simier, Monique

    2009-12-01

    The species diversity of the four major Eastern Boundary Upwelling Ecosystems (EBUEs) is studied and compared with the aim of better understanding their functioning. Functional groups (FGs) of organisms were defined according to their taxonomy, body size and trophic level (TL), and span from plankton to top predators. Four large sub-divisions are defined in each system: two latitudinal sub-divisions (north and south) and two zonal sub-divisions (inshore and offshore), resulting in four sub-ecosystems per EBUE. A semi-quantitative approach is used in which only the dominant species (contributing 90% of overall biomass) are considered. EBUEs are compared in regard to their species composition, dominant species richness and evenness within FGs. The data are interpreted, focusing on latitudinal, zonal and depth gradients of diversity. Trophic flows (inflow and outflow) through the small pelagic fish FG are derived from different Ecopath models. This analysis of the four ecosystems and their sub-divisions does not provide support for the expected wasp-waist food web structure and functioning, with a single or several species of small pelagic fish primarily channelling the energy flow from lower to higher TL. Instead, similar low levels of richness were observed in many FGs of intermediate TL, allowing several energy transfer pathways. The gamma diversity is high due to the geographical distance between EBUEs and the presence or absence of rivers, but not to differences in their latitudinal position. The beta diversity is also high, due to the same factors plus the variation in shelf width and the contrast between inshore and offshore sub-divisions. The differences in richness and evenness among EBUEs are minor and do not explain the higher secondary and tertiary productivity of the Humboldt ecosystem.

  18. Woody plant encroachment into grasslands: spatial patterns of functional group distribution and community development.

    PubMed

    Liu, Feng; Archer, Steven R; Gelwick, Frances; Bai, Edith; Boutton, Thomas W; Wu, Xinyuan Ben

    2013-01-01

    Woody plant encroachment into grasslands has been globally widespread. The woody species invading grasslands represent a variety of contrasting plant functional groups and growth forms. Are some woody plant functional types (PFTs) better suited to invade grasslands than others? To what extent do local patterns of distribution and abundance of woody PFTs invading grasslands reflect intrinsic topoedaphic properties versus plant-induced changes in soil properties? We addressed these questions in the Southern Great Plains, United States at a subtropical grassland known to have been encroached upon by woody species over the past 50-100 years. A total of 20 woody species (9 tree-statured; 11 shrub-statured) were encountered along a transect extending from an upland into a playa basin. About half of the encroaching woody plants were potential N2-fixers (55% of species), but they contributed only 7% to 16 % of the total basal area. Most species and the PFTs they represent were ubiquitously distributed along the topoedaphic gradient, but with varying abundances. Overstory-understory comparisons suggest that while future species composition of these woody communities is likely to change, PFT composition is not. Canonical correspondence analysis (CCA) ordination and variance partitioning (Partial CCA) indicated that woody species and PFT composition in developing woody communities was primarily influenced by intrinsic landscape location variables (e.g., soil texture) and secondarily by plant-induced changes in soil organic carbon and total nitrogen content. The ubiquitous distribution of species and PFTs suggests that woody plants are generally well-suited to a broad range of grassland topoedaphic settings. However, here we only examined categorical and non-quantitative functional traits. Although intrinsic soil properties exerted more control over the floristics of grassland-to-woodland succession did plant modifications of soil carbon and nitrogen concentrations, the latter

  19. Woody Plant Encroachment into Grasslands: Spatial Patterns of Functional Group Distribution and Community Development

    PubMed Central

    Liu, Feng; Archer, Steven R.; Gelwick, Frances; Bai, Edith; Boutton, Thomas W.; Wu, Xinyuan Ben

    2013-01-01

    Woody plant encroachment into grasslands has been globally widespread. The woody species invading grasslands represent a variety of contrasting plant functional groups and growth forms. Are some woody plant functional types (PFTs) better suited to invade grasslands than others? To what extent do local patterns of distribution and abundance of woody PFTs invading grasslands reflect intrinsic topoedaphic properties versus plant-induced changes in soil properties? We addressed these questions in the Southern Great Plains, United States at a subtropical grassland known to have been encroached upon by woody species over the past 50-100 years. A total of 20 woody species (9 tree-statured; 11 shrub-statured) were encountered along a transect extending from an upland into a playa basin. About half of the encroaching woody plants were potential N2-fixers (55% of species), but they contributed only 7% to 16 % of the total basal area. Most species and the PFTs they represent were ubiquitously distributed along the topoedaphic gradient, but with varying abundances. Overstory-understory comparisons suggest that while future species composition of these woody communities is likely to change, PFT composition is not. Canonical correspondence analysis (CCA) ordination and variance partitioning (Partial CCA) indicated that woody species and PFT composition in developing woody communities was primarily influenced by intrinsic landscape location variables (e.g., soil texture) and secondarily by plant-induced changes in soil organic carbon and total nitrogen content. The ubiquitous distribution of species and PFTs suggests that woody plants are generally well-suited to a broad range of grassland topoedaphic settings. However, here we only examined categorical and non-quantitative functional traits. Although intrinsic soil properties exerted more control over the floristics of grassland-to-woodland succession did plant modifications of soil carbon and nitrogen concentrations, the latter

  20. Architecture of 54 moist-forest tree species: traits, trade-offs, and functional groups.

    PubMed

    Poorter, Lourens; Bongers, Laurent; Bongers, Frans

    2006-05-01

    Tree architecture is an important determinant of the height extension, light capture, and mechanical stability of trees, and it allows species to exploit the vertical height gradient in the forest canopy and horizontal light gradients at the forest floor. Tropical tree species partition these gradients through variation in adult stature (Hmax) and light demand. In this study we compare 22 architectural traits for 54 Bolivian moist-forest tree species. We evaluate how architectural traits related to Hmax vary with tree size, and we present a conceptual scheme in which we combine the two axes into four different functional groups. Interspecific correlations between architecture and Hmax varied strongly from negative to positive, depending on the reference sizes used. Stem height was positively related to Hmax at larger reference diameters (14-80 cm). Species height vs. diameter curves often flattened toward their upper ends in association with reproductive maturity for species of all sizes. Thus, adult understory trees were typically shorter than similar-diameter juveniles of larger species. Crown area was negatively correlated with Hmax at small reference heights and positively correlated at larger reference heights (15-34 m). Wide crowns allow the small understory species to intercept light over a large area at the expense of a reduced height growth. Crown length was negatively correlated with Hmax at intermediate reference heights (4-14 m). A long crown enables small understory species to maximize light interception in a light-limited environment. Light-demanding species were characterized by orthotropic stems and branches, large leaves, and a monolayer leaf arrangement. They realized an efficient height growth through the formation of narrow and shallow crowns. Light demand turned out to be a much stronger predictor of tree architecture than Hmax, probably because of the relatively low, open, and semi-evergreen canopy at the research site. The existence of four

  1. A conditional Granger causality model approach for group analysis in functional MRI

    PubMed Central

    Zhou, Zhenyu; Wang, Xunheng; Klahr, Nelson J.; Liu, Wei; Arias, Diana; Liu, Hongzhi; von Deneen, Karen M.; Wen, Ying; Lu, Zuhong; Xu, Dongrong; Liu, Yijun

    2011-01-01

    Granger causality model (GCM) derived from multivariate vector autoregressive models of data has been employed for identifying effective connectivity in the human brain with functional MR imaging (fMRI) and to reveal complex temporal and spatial dynamics underlying a variety of cognitive processes. In the most recent fMRI effective connectivity measures, pairwise GCM has commonly been applied based on single voxel values or average values from special brain areas at the group level. Although a few novel conditional GCM methods have been proposed to quantify the connections between brain areas, our study is the first to propose a viable standardized approach for group analysis of an fMRI data with GCM. To compare the effectiveness of our approach with traditional pairwise GCM models, we applied a well-established conditional GCM to pre-selected time series of brain regions resulting from general linear model (GLM) and group spatial kernel independent component analysis (ICA) of an fMRI dataset in the temporal domain. Datasets consisting of one task-related and one resting-state fMRI were used to investigate connections among brain areas with the conditional GCM method. With the GLM detected brain activation regions in the emotion related cortex during the block design paradigm, the conditional GCM method was proposed to study the causality of the habituation between the left amygdala and pregenual cingulate cortex during emotion processing. For the resting-state dataset, it is possible to calculate not only the effective connectivity between networks but also the heterogeneity within a single network. Our results have further shown a particular interacting pattern of default mode network (DMN) that can be characterized as both afferent and efferent influences on the medial prefrontal cortex (mPFC) and posterior cingulate cortex (PCC). These results suggest that the conditional GCM approach based on a linear multivariate vector autoregressive (MVAR) model can achieve

  2. [Functional groups of natural enemies and their temporal-spatial dynamics in jujube orchard intercropped with herbage].

    PubMed

    Shi, Guanglu; Liu, Suqi; Zhao, Lilin; Cao, Hui; Miao, Zhenwang; Li, Dengke; Feng, Jin; Zhang, Jiugang

    2006-04-01

    In this paper, an investigation was made on the temporal-spatial dynamics of the functional groups of natural enemies in the jujube orchard 2.5 km west of Taigu (112 degrees 8'E, 38 degrees 9'N, 780 m elevation), Shanxi Province in 2002, aimed to work out an effective strategy to control the pests there. In this orchard, four management modes were applied, i. e., intercropping herbage combined with integrated pest management (IPM), intercropping combined with conventional pest management (CM), intercropping with no pest management (NM), and non- intercropping (CK). The results indicated that the total number of natural enemies in IPM, CM and NM was 187.99%, 151.82% and 210.03% higher than CK, respectively, and the recovery and reconstruction rates as well as the average breadth and overlap indices of two dimensional temporal-spatial niches of the functional groups were higher in intercropping modes than in CK. The average diversity index of the functional groups in intercropping modes was significantly bigger than that in CK, but the fluctuation of the diversity standard error of the functional groups was significantly smaller (P < 0.05). The fluctuation trends of the dominance, diversity, and evenness of functional groups had a significant correlation (P< 0.01) with those of species. These results showed that intercropping herbage in jujube orchard was favorable to the conservation, proliferation, and making use of natural enemies. The natural enemy's community in jujube orchard intercropped with herbage was more stable than that without intercropping, and the numbers and functions of the functional groups were differed with different management modes and different stages. Among the functional groups of natural enemies, ladybirds had a stronger ability of recovery, while spiders and parasitoids were weaker. It was feasible to use functional groups instead of species to study the natural enemy's community in jujube orchard.

  3. Exploring patient involvement in healthcare decision making across different education and functional health literacy groups.

    PubMed

    Smith, Sian K; Dixon, Ann; Trevena, Lyndal; Nutbeam, Don; McCaffery, Kirsten J

    2009-12-01

    Education and health literacy potentially limit a person's ability to be involved in decisions about their health. Few studies, however, have explored understandings and experiences of involvement in decision making among patients varying in education and health literacy. This paper reports on a qualitative interview study of 73 men and women living in Sydney, Australia, with varying education and functional health literacy levels. Participants were recruited from a community sample with lower educational attainment, plus an educated sample of University of Sydney alumni. The transcripts were analysed using the 'Framework' approach, a matrix-based method of thematic analysis. We found that participants with different education conceptualised their involvement in decision making in diverse ways. Participants with higher education appeared to conceive their involvement as sharing the responsibility with the doctor throughout the decision-making process. This entailed verifying the credibility of the information and exploring options beyond those presented in the consultation. They also viewed themselves as helping others in their health decisions and acting as information resources. In contrast, participants with lower education appeared to conceive their involvement in terms of consenting to an option recommended by the doctor, and having responsibility for the ultimate decision, to agree or disagree with the recommendation. They also described how relatives and friends sought information on their behalf and played a key role in their decisions. Both education groups described how aspects of the patient-practitioner relationship (e.g. continuity, negotiation, trust) and the practitioner's interpersonal communication skills influenced their involvement. Health information served a variety of needs for all groups (e.g. supporting psychosocial, practical and decision support needs). These findings have practical implications for how to involve patients with different

  4. Differential Abundance of Microbial Functional Groups along the Elevation Gradient from the Coast to the Luquillo Mountains

    EPA Science Inventory

    Microbial communities respond to multiple abiotic and biotic factors that change along elevation gradients. We compare changes in microbial community composition in soil and review previous research on differential abundance of microbial functional groups along an elevation gradi...

  5. Identification of the functional groups on the surface of nanoparticles formed in photonucleation of aldehydes generated during forest fire events

    NASA Astrophysics Data System (ADS)

    Dultsev, Fedor N.; Mik, Ivan A.; Dubtsov, Sergei N.; Dultseva, Galina G.

    2014-11-01

    We describe the new procedure developed to determine the functional groups on the surface of nanoparticles formed in photonucleation of furfural, one of the aldehydes generated during forest fire events. The procedure is based on the detection of nanoparticle rupture from chemically modified surface of the quartz crystal microbalance oscillating in the thickness shear mode under voltage sweep. The rupture force is determined from the voltage at which the rupture occurs. It depends on particle mass and on the affinity of the surface functional groups of the particle to the groups that are present on the modified QCM surface. It was demonstrated with the amine modification of the surface that the nanoparticles formed in furfural photonucleation contain carbonyl and carboxyl groups. The applicability of the method for the investigation of functional groups on the surface of the nanoparticles of atmospheric aerosol is demonstrated.

  6. Sensitivity of Ocean Reflectance Inversion Models for Identifying and Discriminating Between Phytoplankton Functional Groups

    NASA Technical Reports Server (NTRS)

    Werdell, P. Jeremy; Ooesler, Collin S.

    2012-01-01

    The daily, synoptic images provided by satellite ocean color instruments provide viable data streams for observing changes in the biogeochemistrY of marine ecosystems. Ocean reflectance inversion models (ORMs) provide a common mechanism for inverting the "color" of the water observed a satellite into marine inherent optical properties (lOPs) through a combination of empiricism and radiative transfer theory. lOPs, namely the spectral absorption and scattering characteristics of ocean water and its dissolved and particulate constituents, describe the contents of the upper ocean, information critical for furthering scientific understanding of biogeochemical oceanic processes. Many recent studies inferred marine particle sizes and discriminated between phytoplankton functional groups using remotely-sensed lOPs. While all demonstrated the viability of their approaches, few described the vertical distributions of the water column constituents under consideration and, thus, failed to report the biophysical conditions under which their model performed (e.g., the depth and thickness of the phytoplankton bloom(s)). We developed an ORM to remotely identifY Noctiluca miliaris and other phytoplankton functional types using satellite ocean color data records collected in the northern Arabian Sea. Here, we present results from analyses designed to evaluate the applicability and sensitivity of the ORM to varied biophysical conditions. Specifically, we: (1) synthesized a series of vertical profiles of spectral inherent optical properties that represent a wide variety of bio-optical conditions for the northern Arabian Sea under aN Miliaris bloom; (2) generated spectral remote-sensing reflectances from these profiles using Hydrolight; and, (3) applied the ORM to the synthesized reflectances to estimate the relative concentrations of diatoms and N Miliaris for each example. By comparing the estimates from the inversion model to those from synthesized vertical profiles, we were able to

  7. High Mobility Group Box Protein-1 Correlates with Renal Function in Chronic Kidney Disease (CKD)

    PubMed Central

    Bruchfeld, Annette; Qureshi, Abdul Rashid; Lindholm, Bengt; Barany, Peter; Yang, LiHong; Stenvinkel, Peter; Tracey, Kevin J

    2008-01-01

    Chronic kidney disease (CKD) is associated with inflammation and malnutrition and carries a markedly increased risk of cardiovascular disease (CVD). High Mobility Group Box Protein-1 (HMGB-1) is a 30-kDa nuclear and cytosolic protein known as a transcription and growth factor, recently identified as a proinflammatory mediator of tissue injury. Recent data implicates HMGB-1 in endotoxin lethality, rheumatoid arthritis, and atherosclerosis. The aim of this post-hoc, cross-sectional study was to determine whether HMGB-1 serum levels are elevated in CKD patients. The study groups were categorized as follows: 110 patients starting dialysis defined as CKD 5; 67 patients with moderately to severely reduced renal function or CKD 3–4; and 48 healthy controls. High-sensitivity C-reactive-protein (hs-CRP), interleukin-6 (IL-6), tumor necrosis factor (TNF), serum-albumin (S-albumin), hemoglobin A1c (HbA1c), hemoglobin, subjective global nutritional assessment (SGA), and glomerular filtration rate (GFR) were analyzed. Kruskal-Wallis test was used to compare groups and Spearman’s rank correlation test was used for continuous variables. HMGB-1, measured by Western blot, was significantly (P < 0.001) elevated in CKD 5 (146.7 ± 58.6 ng/mL) and CKD 3–4 (85.6 ± 31.8) compared with controls (10.9 ± 10.5). HMGB-1 levels were correlated positively with TNF (Rho = 0.52; P < 0.001), hs-CRP (Rho = 0.38; P < 0.001), IL-6 (Rho = 0.30; P < 0.001), HbA1c (Rho = 0.14; P = 0.02) and SGA (Rho = 0.21; P = 0.002) and negatively correlated with GFR (Rho = –0.69; P = 0.0001), Hb (Rho = –0.60; P < 0.001), S-albumin (Rho = –0.31; P < 0.001). The current study has revealed that HMGB-1 is elevated significantly in CKD patients and correlates with GFR as well as markers of inflammation and malnutrition. Future studies may delineate whether HMGB-1 is also a marker of disease activity and severity as well as a predictor of outcome in CKD. PMID:18317568

  8. Anion Coordination in Metal-Organic Frameworks Functionalized with Urea Hydrogen-Bonding Groups

    SciTech Connect

    Custelcean, Radu; Moyer, Bruce A.; Bryantsev, Vyacheslav; Hay, Benjamin P.

    2005-12-15

    A series of metal-organic frameworks (MOFs) functionalized with urea hydrogen-bonding groups have been designed, synthesized, and structurally analyzed by single crystal X-ray diffraction to evaluate the efficacy of anion binding within the structural constraints of the MOFs. We found that urea-based functionalities may be used for anion binding within metal-organic frameworks when the tendency for urea???urea self-association is decreased by strengthening the intramolelcular CH???O hydrogen bonding of N-phenyl substituents to the carbonyl oxygen atom. Theoretical calculations indicate that N,N?-bis(m-pyridyl)urea (BPU) and N,N?-bis(m-cyanophenyl)urea (BCPU) should have enhanced hydrogen-bonding donor abilities toward anions and decreased tendencies to self-associate into hydrogen-bonded chains compared to other disubstituted ureas. Accordingly, BPU and BCPU were incorporated in MOFs as linkers through coordination of various Zn, Cu, and Ag transition metal salts, including Zn(ClO4)2, ZnSO4, Cu(NO3)2, Cu(CF3SO3)2, AgNO3 and AgSO3CH3. Structural analysis by single-crystal X-ray diffraction showed that these linkers are versatile anion binders, capable of chelate hydrogen bonding to all of the oxoanions explored. Anion binding by the urea functionalities was found to successfully compete with urea self-association in all cases except for that of charge-diffuse perchlorate. This research was sponsored by the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences of the U.S. Department of Energy, under contract number DE-AC05-00OR22725 with Oak Ridge National Laboratory (managed by UT-Battelle, LLC), and performed at Oak Ridge National laboratory and Pacific Northwest National Laboratory (managed by Battelle for the U.S. Department of Energy under contract DE-AC05-76RL01830). This research was performed in part using the Molecular Science Computing Facility (MSCF) in the William R. Wiley Environmental Molecular Sciences laboratory

  9. Size distributions of shocks and static avalanches from the functional renormalization group.

    PubMed

    Le Doussal, Pierre; Wiese, Kay Jörg

    2009-05-01

    Interfaces pinned by quenched disorder are often used to model jerky self-organized critical motion. We study static avalanches, or shocks, defined here as jumps between distinct global minima upon changing an external field. We show how the full statistics of these jumps is encoded in the functional-renormalization-group fixed-point functions. This allows us to obtain the size distribution P(S) of static avalanches in an expansion in the internal dimension d of the interface. Near and above d=4 this yields the mean-field distribution P(S) approximately S;{-3/2}e;{-S4S_{m}} , where S_{m} is a large-scale cutoff, in some cases calculable. Resumming all one-loop contributions, we find P(S) approximately S;{-tau}exp(C(SS_{m});{1/2}-B/4(S/S_{m});{delta}) , where B , C , delta , and tau are obtained to first order in =4-d . Our result is consistent to O() with the relation tau=tau_{zeta}:=2-2/d+zeta , where zeta is the static roughness exponent, often conjectured to hold at depinning. Our calculation applies to all static universality classes, including random-bond, random-field, and random-periodic disorders. Extended to long-range elastic systems, it yields a different size distribution for the case of contact-line elasticity, with an exponent compatible with tau=2-1/d+zeta to O(=2-d) . We discuss consequences for avalanches at depinning and for sandpile models, relations to Burgers turbulence and the possibility that the relation tau=tau_{zeta} be violated to higher loop order. Finally, we show that the avalanche-size distribution on a hyperplane of codimension one is in mean field (valid close to and above d=4 ) given by P(S) approximately K_{13}(S)S , where K is the Bessel- K function, thus tau_{hyperplane}=4/3 .

  10. Synthesis of nine-atom deltahedral Zintl ions of germanium and their functionalization with organic groups.

    PubMed

    Gillett-Kunnath, Miriam M; Sevov, Slavi C

    2012-01-01

    Although the first studies of Zintl ions date between the late 1890's and early 1930's they were not structurally characterized until many years later. Their redox chemistry is even younger, just about ten years old, but despite this short history these deltahedral clusters ions E9(n-) (E = Si, Ge, Sn, Pb; n = 2, 3, 4) have already shown interesting and diverse reactivity and have been at the forefront of rapidly developing and exciting new chemistry. Notable milestones are the oxidative coupling of Ge9(4-) clusters to oligomers and infinite chains, their metallation, capping by transition-metal organometallic fragments, insertion of a transition-metal atom at the center of the cluster which is sometimes combined with capping and oligomerization, addition of main-group organometallic fragments as exo-bonded substituents, and functionalization with various organic residues by reactions with organic halides and alkynes. This latter development of attaching organic fragments directly to the clusters has opened up a new field, namely organo-Zintl chemistry, that is potentially fertile for further synthetic explorations, and it is the step-by-step procedure for the synthesis of germanium-divinyl clusters described herein. The initial steps outline the synthesis of an intermetallic precursor of K4Ge9 from which the Ge9(4-) clusters are extracted later in solution. This involves fused-silica glass blowing, arc-welding of niobium containers, and handling of highly air-sensitive materials in a glove box. The air-sensitive K4Ge9 is then dissolved in ethylenediamine in the box and then alkenylated by a reaction with Me3SiC≡CSiMe3. The reaction is followed by electrospray mass spectrometry while the resulting solution is used for obtaining single crystals containing the functionalized clusters [H2C=CH-Ge9-CH=CH2](2-). For this purpose the solution is centrifuged, filtered, and carefully layered with a toluene solution of 18-crown-6. Left undisturbed for a few days, the so

  11. Synthesis of Nine-atom Deltahedral Zintl Ions of Germanium and their Functionalization with Organic Groups

    PubMed Central

    Gillett-Kunnath, Miriam M.; Sevov, Slavi C.

    2012-01-01

    Although the first studies of Zintl ions date between the late 1890's and early 1930's they were not structurally characterized until many years later.1,2 Their redox chemistry is even younger, just about ten years old, but despite this short history these deltahedral clusters ions E9n- (E = Si, Ge, Sn, Pb; n = 2, 3, 4) have already shown interesting and diverse reactivity and have been at the forefront of rapidly developing and exciting new chemistry.3-6 Notable milestones are the oxidative coupling of Ge94- clusters to oligomers and infinite chains,7-19 their metallation,14-16,20-25 capping by transition-metal organometallic fragments,26-34 insertion of a transition-metal atom at the center of the cluster which is sometimes combined with capping and oligomerization,35-47 addition of main-group organometallic fragments as exo-bonded substituents,48-50 and functionalization with various organic residues by reactions with organic halides and alkynes.51-58 This latter development of attaching organic fragments directly to the clusters has opened up a new field, namely organo-Zintl chemistry, that is potentially fertile for further synthetic explorations, and it is the step-by-step procedure for the synthesis of germanium-divinyl clusters described herein. The initial steps outline the synthesis of an intermetallic precursor of K4Ge9 from which the Ge94- clusters are extracted later in solution. This involves fused-silica glass blowing, arc-welding of niobium containers, and handling of highly air-sensitive materials in a glove box. The air-sensitive K4Ge9 is then dissolved in ethylenediamine in the box and then alkenylated by a reaction with Me3SiC≡CSiMe3. The reaction is followed by electrospray mass spectrometry while the resulting solution is used for obtaining single crystals containing the functionalized clusters [H2C=CH-Ge9-CH=CH2]2-. For this purpose the solution is centrifuged, filtered, and carefully layered with a toluene solution of 18-crown-6. Left

  12. FT-IR quantification of the carbonyl functional group in aqueous-phase secondary organic aerosol from phenols

    NASA Astrophysics Data System (ADS)

    George, Kathryn M.; Ruthenburg, Travis C.; Smith, Jeremy; Yu, Lu; Zhang, Qi; Anastasio, Cort; Dillner, Ann M.

    2015-01-01

    Recent findings suggest that secondary organic aerosols (SOA) formed from aqueous-phase reactions of some organic species, including phenols, contribute significantly to particulate mass in the atmosphere. In this study, we employ a Fourier transform infrared (FT-IR) spectroscopic technique to identify and quantify the functional group makeup of phenolic SOA. Solutions containing an oxidant (hydroxyl radical or 3,4-dimethoxybenzaldehyde) and either one phenol (phenol, guaiacol, or syringol) or a mixture of phenols mimicking softwood or hardwood emissions were illuminated to make SOA, atomized, and collected on a filter. We produced laboratory standards of relevant organic compounds in order to develop calibrations for four functional groups: carbonyls (Cdbnd O), saturated C-H, unsaturated C-H and O-H. We analyzed the SOA samples with transmission FT-IR to identify and determine the amounts of the four functional groups. The carbonyl functional group accounts for 3-12% of the SOA sample mass in single phenolic SOA samples and 9-14% of the SOA sample mass in mixture samples. No carbonyl functional groups are present in the initial reactants. Varying amounts of each of the other functional groups are observed. Comparing carbonyls measured by FT-IR (which could include aldehydes, ketones, esters, and carboxylic acids) with eight small carboxylic acids measured by ion chromatography indicates that the acids only account for an average of 20% of the total carbonyl reported by FT-IR.

  13. Design of Chitosan-Grafted Carbon Nanotubes: Evaluation of How the -OH Functional Group Affects Cs+ Adsorption.

    PubMed

    Yang, Shubin; Shao, Dadong; Wang, Xiangke; Hou, Guangshun; Nagatsu, Masaaki; Tan, Xiaoli; Ren, Xuemei; Yu, Jitao

    2015-05-01

    In order to explore the effect of -OH functional groups in Cs+ adsorption, we herein used the low temperature plasma-induced grafting method to graft chitosan onto carbon nanotubes (denoted as CTS-g-CNTs), as raw-CNTs have few functional groups and chitosan has a large number of -OH functional groups. The synthesized CTS-g-CNT composites were characterized using different techniques. The effect of -OH functional groups in the Cs+ adsorption process was evaluated by comparison of the adsorption properties of raw-CNTs with and without grafting chitosan. The variation of environmental conditions such as pH and contact time was investigated. A comparison of contaminated seawater and simulated groundwater was also evaluated. The results indicated that: (1) the adsorption of Cs+ ions was strongly dependent on pH and the competitive cations; (2) for CNT-based material, the -OH functional groups have a positive effect on Cs+ removal; (3) simulated contaminated groundwater can be used to model contaminated seawater to evaluate the adsorption property of CNTs-based material. These results showed direct observational evidence on the effect of -OH functional groups for Cs+ adsorption. Our findings are important in providing future directions to design and to choose effective material to remedy the removal of radioactive cesium from contaminated groundwater and seawater, crucial for public health and the human social environment.

  14. Design of Chitosan-Grafted Carbon Nanotubes: Evaluation of How the –OH Functional Group Affects Cs+ Adsorption

    PubMed Central

    Yang, Shubin; Shao, Dadong; Wang, Xiangke; Hou, Guangshun; Nagatsu, Masaaki; Tan, Xiaoli; Ren, Xuemei; Yu, Jitao

    2015-01-01

    In order to explore the effect of –OH functional groups in Cs+ adsorption, we herein used the low temperature plasma-induced grafting method to graft chitosan onto carbon nanotubes (denoted as CTS-g-CNTs), as raw-CNTs have few functional groups and chitosan has a large number of –OH functional groups. The synthesized CTS-g-CNT composites were characterized using different techniques. The effect of –OH functional groups in the Cs+ adsorption process was evaluated by comparison of the adsorption properties of raw-CNTs with and without grafting chitosan. The variation of environmental conditions such as pH and contact time was investigated. A comparison of contaminated seawater and simulated groundwater was also evaluated. The results indicated that: (1) the adsorption of Cs+ ions was strongly dependent on pH and the competitive cations; (2) for CNT-based material, the –OH functional groups have a positive effect on Cs+ removal; (3) simulated contaminated groundwater can be used to model contaminated seawater to evaluate the adsorption property of CNTs-based material. These results showed direct observational evidence on the effect of –OH functional groups for Cs+ adsorption. Our findings are important in providing future directions to design and to choose effective material to remedy the removal of radioactive cesium from contaminated groundwater and seawater, crucial for public health and the human social environment. PMID:26006711

  15. Submicron Organic Aerosol Function Groups during the International Chemistry Experiment in the Arctic LOwer Troposphere (ICEALOT)

    NASA Astrophysics Data System (ADS)

    Russell, L. M.; Shaw, P. M.; Quinn, P. K.; Bates, T. S.

    2008-12-01

    Aerosol organic mass (OM) components are expected to have significant direct and indirect impacts on Arctic climate, especially during springtime Arctic haze. The chemical and physical properties of OM in Arctic aerosol remain largely unconstrained. The R/V Knorr traveled between Iceland and the Barents Sea during the ice-free months of March and April of 2008 and collected submicron particles on teflon filters for Fourier Transform Infrared (FTIR) spectroscopy to identify and quantify organic functional groups. Time series and composition are presented along with air mass back trajectories to indicate source regions. Early findings identify alcohols, alkanes, and carboxylic acids, with smaller amounts of amines, aromatics, alkenes and carbonyls. These data show the important contributions of organic oxygen and nitrogen in the Arctic region. Single particle analysis by Near-edge X-ray Absorption Fine Structure (NEXAFS) Scanning Transmission X- ray Microscopy (STXM) provides additional information about the distribution and morphology of the types of organic particles. Comparison to collocated simultaneous measurements by other techniques showed good agreement for OM and oxygenated organic fractions.

  16. Long-term warming alters richness and composition of taxonomic and functional groups of arctic fungi.

    PubMed

    Geml, József; Morgado, Luis N; Semenova, Tatiana A; Welker, Jeffrey M; Walker, Marilyn D; Smets, Erik

    2015-08-01

    Fungi, including symbionts, pathogens and decomposers, play crucial roles in community dynamics and nutrient cycling in terrestrial ecosystems. Despite their ecological importance, the response of most arctic fungi to climate warming is unknown, so are their potential roles in driving the observed and predicted changes in tundra communities. We carried out deep DNA sequencing of soil samples to study the long-term effects of experimental warming on fungal communities in dry heath and moist tussock tundra in Arctic Alaska. The data presented here indicate that fungal community composition responds strongly to warming in the moist tundra, but not in the dry tundra. While total fungal richness was not significantly affected by warming, there were clear correlations among operational taxonomic unit richness of various ecological and taxonomic groups and long-term warming. Richness of ectomycorrhizal, ericoid mycorrhizal and lichenized fungi generally decreased with warming, while richness of saprotrophic, plant and animal pathogenic, and root endophytic fungi tended to increase in the warmed plots. More importantly, various taxa within these functional guilds followed opposing trends that highlight the importance of species-specific responses to warming. We recommend that species-level ecological differences be taken into account in climate change and nutrient cycling studies that involve arctic fungi. PMID:26253509

  17. Effect of bioceramic functional groups on drug binding and release kinetics

    NASA Astrophysics Data System (ADS)

    Trujillo, Christopher

    Bioceramics have been studied extensively as drug delivery systems (DDS). Those studies have aimed to tailor the drug binding and release kinetics to successfully treat infections and other diseases. This research suggests that the drug binding and release kinetics are predominantly driven by the functional groups available on the surface of a bioceramic. The goal of the present study is to explain the role of silicate and phosphate functional groups in drug binding to and release kinetics from bioceramics. alpha-cristobalite (Cris; SiO2) particles (90-150 microm) were prepared and doped with 0 microg (P-0), 39.1 microg (P-39.1), 78.2 microg (P-78.2), 165.5 microg (P-165.5) or 331 microg (P-331) of P 2O5 per gram Cris, using 85% orthophosphoric (H3PO 4) acid and thermal treatment. The material structure was analyzed using X-ray diffraction (XRD) with Rietveld Refinement and Fourier Transform Infrared (FTIR) spectroscopy with Gaussian fitting. XRD demonstrated an increase from sample P-0 (170.5373 A3) to P-331 (170.6466 A 3) in the unit cell volume as the P2O5 concentration increased in the material confirming phosphate silicate substitution in Cris. Moreover, FTIR showed the characteristic bands of phosphate functional groups of nu4 PO4/O-P-O bending, P-O-P stretching, P-O-P bending, P=O stretching, and P-O-H bending in doped Cris indicating phosphate incorporation in the silicate structure. Furthermore, FTIR showed that the nu4 PO4/O-P-O bending band around 557.6 cm-1 and P=O stretching band around 1343.9 cm-1 increased in area for samples P-39.1 to P-331 from 3.5 to 10.5 and from 10.1 to 22.4, respectively due to phosphate doping. In conjunction with the increase of the nu4 PO4/O-P-O bending band and P=O stretching band, a decrease in area of the O-Si-O bending bands around 488.1 and 629.8 cm-1 was noticed for samples P-39.1 to P-331 from 5 to 2 and from 11.8 to 5.4, respectively. Furthermore, Cris samples (200 mg, n=5 for each sample) were immersed separately in

  18. Classification of ion mobility spectra by functional groups using neural networks

    NASA Technical Reports Server (NTRS)

    Bell, S.; Nazarov, E.; Wang, Y. F.; Eiceman, G. A.

    1999-01-01

    Neural networks were trained using whole ion mobility spectra from a standardized database of 3137 spectra for 204 chemicals at various concentrations. Performance of the network was measured by the success of classification into ten chemical classes. Eleven stages for evaluation of spectra and of spectral pre-processing were employed and minimums established for response thresholds and spectral purity. After optimization of the database, network, and pre-processing routines, the fraction of successful classifications by functional group was 0.91 throughout a range of concentrations. Network classification relied on a combination of features, including drift times, number of peaks, relative intensities, and other factors apparently including peak shape. The network was opportunistic, exploiting different features within different chemical classes. Application of neural networks in a two-tier design where chemicals were first identified by class and then individually eliminated all but one false positive out of 161 test spectra. These findings establish that ion mobility spectra, even with low resolution instrumentation, contain sufficient detail to permit the development of automated identification systems.

  19. Threshold-free estimation of functional antibody titers of a group B streptococcus opsonophagocytic killing assay.

    PubMed

    Moraschini, Luca; Passalacqua, Irene; Fabbrini, Monica; Margarit Y Ros, Immaculada; Rigat, Fabio

    2015-01-01

    Opsonophagocytic killing assays (OPKA) are routinely used for the quantification of bactericidal antibodies in blood serum samples. Quantification of the OPKA readout, the titer, provides the basis for the statistical analysis of vaccine clinical trials having functional immune response endpoints. Traditional OPKA titers are defined as the maximum serum dilution yielding a predefined bacterial killing threshold value, and they are estimated by fitting a dose-response model to the dilution-killing curve. This paper illustrates a novel definition of titer, the threshold-free titer, which preserves biological interpretability while not depending on any killing threshold or on a postulated shape of the dose-response curve. These titers are shown to be more precise than the traditional threshold-based titers when using simulated and experimental group B streptococcus OPKA experimental data. Also, titer linearity is shown to be not measurable when using threshold-based titers, whereas it becomes measurable using threshold-free titers. The biological interpretability and operational characteristics demonstrated here indicate that threshold-free titers are an appropriate tool for the routine analysis of OPKA data.

  20. Hierarchical parallelisation of functional renormalisation group calculations - hp-fRG

    NASA Astrophysics Data System (ADS)

    Rohe, Daniel

    2016-10-01

    The functional renormalisation group (fRG) has evolved into a versatile tool in condensed matter theory for studying important aspects of correlated electron systems. Practical applications of the method often involve a high numerical effort, motivating the question in how far High Performance Computing (HPC) can leverage the approach. In this work we report on a multi-level parallelisation of the underlying computational machinery and show that this can speed up the code by several orders of magnitude. This in turn can extend the applicability of the method to otherwise inaccessible cases. We exploit three levels of parallelisation: Distributed computing by means of Message Passing (MPI), shared-memory computing using OpenMP, and vectorisation by means of SIMD units (single-instruction-multiple-data). Results are provided for two distinct High Performance Computing (HPC) platforms, namely the IBM-based BlueGene/Q system JUQUEEN and an Intel Sandy-Bridge-based development cluster. We discuss how certain issues and obstacles were overcome in the course of adapting the code. Most importantly, we conclude that this vast improvement can actually be accomplished by introducing only moderate changes to the code, such that this strategy may serve as a guideline for other researcher to likewise improve the efficiency of their codes.

  1. Colloidal inverse bicontinuous cubic membranes of block copolymers with tunable surface functional groups.

    PubMed

    La, Yunju; Park, Chiyoung; Shin, Tae Joo; Joo, Sang Hoon; Kang, Sebyung; Kim, Kyoung Taek

    2014-06-01

    Analogous to the complex membranes found in cellular organelles, such as the endoplasmic reticulum, the inverse cubic mesophases of lipids and their colloidal forms (cubosomes) possess internal networks of water channels arranged in crystalline order, which provide a unique nanospace for membrane-protein crystallization and guest encapsulation. Polymeric analogues of cubosomes formed by the direct self-assembly of block copolymers in solution could provide new polymeric mesoporous materials with a three-dimensionally organized internal maze of large water channels. Here we report the self-assembly of amphiphilic dendritic-linear block copolymers into polymer cubosomes in aqueous solution. The presence of precisely defined bulky dendritic blocks drives the block copolymers to form spontaneously highly curved bilayers in aqueous solution. This results in the formation of colloidal inverse bicontinuous cubic mesophases. The internal networks of water channels provide a high surface area with tunable surface functional groups that can serve as anchoring points for large guests such as proteins and enzymes. PMID:24848240

  2. Removal of a single minor-groove functional group eliminates A-tract curvature.

    PubMed

    Meena; Sun, Zhenhua; Mulligan, Christine; McLaughlin, Larry W

    2006-09-13

    Much of the work in studying the phenomenon of A-tract curvature has involved the insertion of modified residues into the A-tract sequence and then cross-correlation of the structural differences with the resulting curvature effects. In the A-tract sequence d(A-T)5, removal of a single functional group (the O2-carbonyl of the central dT residue) by its replacement with hydrogen completely eliminates the curvature properties. This atom-specific change was accomplished by using the C-nucleoside dm32P in which the O2-carbonyl is replaced with -H but normal Watson-Crick hydrogen bonding is maintained. Similar derivatives with -F (dF62P) or -CH3 (dm62P) when present for the central dT residue also eliminate curvature. Finally, we have shown that the extent of curvature for sequences containing this carbonyl are sensitive to the [Mg2+], while those lacking the carbonyl show little to no Mg2+ dependence, strongly suggesting, we believe, a role for Na+/Mg2+ cooperative interactions in the minor groove to explain the curvature phenomenon.

  3. Long-term warming alters richness and composition of taxonomic and functional groups of arctic fungi.

    PubMed

    Geml, József; Morgado, Luis N; Semenova, Tatiana A; Welker, Jeffrey M; Walker, Marilyn D; Smets, Erik

    2015-08-01

    Fungi, including symbionts, pathogens and decomposers, play crucial roles in community dynamics and nutrient cycling in terrestrial ecosystems. Despite their ecological importance, the response of most arctic fungi to climate warming is unknown, so are their potential roles in driving the observed and predicted changes in tundra communities. We carried out deep DNA sequencing of soil samples to study the long-term effects of experimental warming on fungal communities in dry heath and moist tussock tundra in Arctic Alaska. The data presented here indicate that fungal community composition responds strongly to warming in the moist tundra, but not in the dry tundra. While total fungal richness was not significantly affected by warming, there were clear correlations among operational taxonomic unit richness of various ecological and taxonomic groups and long-term warming. Richness of ectomycorrhizal, ericoid mycorrhizal and lichenized fungi generally decreased with warming, while richness of saprotrophic, plant and animal pathogenic, and root endophytic fungi tended to increase in the warmed plots. More importantly, various taxa within these functional guilds followed opposing trends that highlight the importance of species-specific responses to warming. We recommend that species-level ecological differences be taken into account in climate change and nutrient cycling studies that involve arctic fungi.

  4. Effect of bioceramic functional groups on drug binding and release kinetics

    NASA Astrophysics Data System (ADS)

    Trujillo, Christopher

    Bioceramics have been studied extensively as drug delivery systems (DDS). Those studies have aimed to tailor the drug binding and release kinetics to successfully treat infections and other diseases. This research suggests that the drug binding and release kinetics are predominantly driven by the functional groups available on the surface of a bioceramic. The goal of the present study is to explain the role of silicate and phosphate functional groups in drug binding to and release kinetics from bioceramics. alpha-cristobalite (Cris; SiO2) particles (90-150 microm) were prepared and doped with 0 microg (P-0), 39.1 microg (P-39.1), 78.2 microg (P-78.2), 165.5 microg (P-165.5) or 331 microg (P-331) of P 2O5 per gram Cris, using 85% orthophosphoric (H3PO 4) acid and thermal treatment. The material structure was analyzed using X-ray diffraction (XRD) with Rietveld Refinement and Fourier Transform Infrared (FTIR) spectroscopy with Gaussian fitting. XRD demonstrated an increase from sample P-0 (170.5373 A3) to P-331 (170.6466 A 3) in the unit cell volume as the P2O5 concentration increased in the material confirming phosphate silicate substitution in Cris. Moreover, FTIR showed the characteristic bands of phosphate functional groups of nu4 PO4/O-P-O bending, P-O-P stretching, P-O-P bending, P=O stretching, and P-O-H bending in doped Cris indicating phosphate incorporation in the silicate structure. Furthermore, FTIR showed that the nu4 PO4/O-P-O bending band around 557.6 cm-1 and P=O stretching band around 1343.9 cm-1 increased in area for samples P-39.1 to P-331 from 3.5 to 10.5 and from 10.1 to 22.4, respectively due to phosphate doping. In conjunction with the increase of the nu4 PO4/O-P-O bending band and P=O stretching band, a decrease in area of the O-Si-O bending bands around 488.1 and 629.8 cm-1 was noticed for samples P-39.1 to P-331 from 5 to 2 and from 11.8 to 5.4, respectively. Furthermore, Cris samples (200 mg, n=5 for each sample) were immersed separately in

  5. The Effectiveness of a Multidisciplinary Group Rehabilitation Program on the Psychosocial Functioning of Elderly People Who Are Visually Impaired

    ERIC Educational Resources Information Center

    Alma, Manna A.; Groothoff, Johan W.; Melis-Dankers, Bart J. M.; Suurmeijer, Theo P. B. M.; van der Mei, Sijrike F.

    2013-01-01

    Introduction: The pilot study reported here determined the effectiveness of a multidisciplinary group rehabilitation program, Visually Impaired Elderly Persons Participating (VIPP), on psychosocial functioning. Methods: The single-group pretest-posttest pilot study included 29 persons with visual impairments (aged 55 and older) who were referred…

  6. Acceptorless dehydrogenation of C-C single bonds adjacent to functional groups by metal-ligand cooperation.

    PubMed

    Kusumoto, Shuhei; Akiyama, Midori; Nozaki, Kyoko

    2013-12-18

    Unprecedented direct acceptorless dehydrogenation of C-C single bonds adjacent to functional groups to form α,β-unsaturated compounds has been accomplished by using a new class of group 9 metal complexes. Metal-ligand cooperation operated by the hydroxycyclopentadienyl ligand was proposed to play a major role in the catalytic transformation. PMID:24299029

  7. Mixture Item Response Theory-MIMIC Model: Simultaneous Estimation of Differential Item Functioning for Manifest Groups and Latent Classes

    ERIC Educational Resources Information Center

    Bilir, Mustafa Kuzey

    2009-01-01

    This study uses a new psychometric model (mixture item response theory-MIMIC model) that simultaneously estimates differential item functioning (DIF) across manifest groups and latent classes. Current DIF detection methods investigate DIF from only one side, either across manifest groups (e.g., gender, ethnicity, etc.), or across latent classes…

  8. Differential Item Functioning (DIF) Analysis of Computation, Word Problem and Geometry Questions across Gender and SES Groups.

    ERIC Educational Resources Information Center

    Berberoglu, Giray

    1995-01-01

    Item characteristic curves were compared across gender and socioeconomic status (SES) groups for the university entrance mathematics examination in Turkey to see if any group had an advantage in solving computation, word-problem, or geometry questions. Differential item functioning was found, and patterns are discussed. (SLD)

  9. Surface modification of silicone tubes by functional carboxyl and amine, but not peroxide groups followed by collagen immobilization improves endothelial cell stability and functionality.

    PubMed

    Salehi-Nik, Nasim; Amoabediny, Ghassem; Shokrgozar, Mohammad Ali; Mottaghy, Khosrow; Klein-Nulend, Jenneke; Zandieh-Doulabi, Behrouz

    2015-03-02

    Surface modification by functional groups promotes endothelialization in biohybrid artificial lungs, but whether it affects endothelial cell stability under fluid shear stress, and the release of anti-thrombotic factors, e.g. nitric oxide (NO), is unknown. We aimed to test whether surface-modified silicone tubes containing different functional groups, but similar wettability, improve collagen immobilization, endothelialization, cell stability and cell-mediated NO-release. Peroxide, carboxyl, and amine-groups increased collagen immobilization (41-76%). Only amine-groups increased ultimate tensile strength (2-fold). Peroxide and amine enhanced (1.5-2.5 fold), but carboxyl-groups decreased (2.9-fold) endothelial cell number after 6 d. After collagen immobilization, cell numbers were enhanced by all group-modifications (2.8-3.8 fold). Cells were stable under 1 h-fluid shear stress on amine, but not carboxyl or peroxide-group-modified silicone (>50% cell detachment), while cells were also stable on carboxyl-group-modified silicone with immobilized collagen. NO-release was increased by peroxide and amine (1.1-1.7 fold), but decreased by carboxyl-group-modification (9.8-fold), while it increased by all group-modifications after collagen immobilization (1.8-2.8 fold). Only the amine-group-modification changed silicone stiffness and transparency. In conclusion, silicone-surface modification of blood-contacting parts of artificial lungs with carboxyl and amine, but not peroxide-groups followed by collagen immobilization allows the formation of a stable functional endothelial cell layer. Amine-group-modification seems undesirable since it affected silicone's physical properties.

  10. Using Cochran's Z Statistic to Test the Kernel-Smoothed Item Response Function Differences between Focal and Reference Groups

    ERIC Educational Resources Information Center

    Zheng, Yinggan; Gierl, Mark J.; Cui, Ying

    2010-01-01

    This study combined the kernel smoothing procedure and a nonparametric differential item functioning statistic--Cochran's Z--to statistically test the difference between the kernel-smoothed item response functions for reference and focal groups. Simulation studies were conducted to investigate the Type I error and power of the proposed…

  11. Extended Functional Groups (EFG): An Efficient Set for Chemical Characterization and Structure-Activity Relationship Studies of Chemical Compounds.

    PubMed

    Salmina, Elena S; Haider, Norbert; Tetko, Igor V

    2015-01-01

    The article describes a classification system termed "extended functional groups" (EFG), which are an extension of a set previously used by the CheckMol software, that covers in addition heterocyclic compound classes and periodic table groups. The functional groups are defined as SMARTS patterns and are available as part of the ToxAlerts tool (http://ochem.eu/alerts) of the On-line CHEmical database and Modeling (OCHEM) environment platform. The article describes the motivation and the main ideas behind this extension and demonstrates that EFG can be efficiently used to develop and interpret structure-activity relationship models. PMID:26703557

  12. Building the Emotional Intelligence and Effective Functioning of Student Work Groups: Evaluation of an Instructional Program

    ERIC Educational Resources Information Center

    Peterson, Christina Hamme

    2012-01-01

    Group-based learning is common practice in university classrooms. Despite the frequent student complaint of social loafing from teammates, methods for teaching students how to address teamwork issues are rarely incorporated into group assignments. Students are instructed on their final product, rather than their group process. In this article, an…

  13. The Structure and Function of Group Training Companies in Australia. Support Document

    ERIC Educational Resources Information Center

    Croce, N.; Macdonald, Duncan; Toner, Phillip; Turner, Cathy

    2004-01-01

    This document was produced by the authors based on their research for the report "Group Training in Australia: A Study of Group Training Organisations and Host Employers", and is an added resource for further information. [Full Report available at ED493992.] Support Document 2, titled " Group Training and Host Employers in Australia", is also…

  14. Functional Group Composition of Semivolatile Compounds Present in Submicron Organic Aerosol

    NASA Astrophysics Data System (ADS)

    Ruggeri, G.; Modini, R. L.; Iannarelli, R.; Rossi, M. J.; Takahama, S.

    2014-12-01

    Semivolatile organic compounds can partition between gas and particle phase in atmospheric conditions and can be volatilized and lost when the aerosol sampling is performed onto PTFE filters (Eatough et al., 1993). In this work, semivolatile compounds are collected onto carbon impregnated glass fiber-cellulose filters placed in series after an activated carbon denuder and PTFE filter which collects submicron aerosol particles of low volatility (Subramanian et al., 2004). The semivolatile compounds accumulated on the cellulose-glass fiber filters are desorbed by vacuum and injected into a stainless steel chamber that enables cold-trapping. The vapors in this chamber are condensed onto a low-temperature silicon window, and the composition of deposited vapors are analysed by transmission-mode Fourier Transform Infrared (FTIR) spectroscopy (Delval and Rossi, 2004). Functional group composition of semivolatile compounds that can be desorbed from the aerosol phase and its relationship with the apparent low-volatile fraction composition will be presented. Eatough, D.J., Wadsworth, A., Eatough, D.A., Crawford, J.W., Hansen, L.D., Lewis, E.A., 1993. A multiple-system, multi-channel diffusion denuder sampler for the determination of fine-particulate organic material in the atmosphere. Atmospheric Environment. Part A. General Topics 27, 1213-1219. Subramanian, R., Khlystov, A.Y., Cabada, J.C., Robinson, A.L., 2004. Positive and negative artifacts in particulate organic carbon measurements with denuded and undenuded sampler configurations. Aerosol Science and Technology 38, 27-48. Delval, C., Rossi, M.J., 2004. The kinetics of condensation and evaporation of H2O from pure ice in the range 173-223 K: a quartz crystal microbalance study. Physical Chemistry Chemical Physics 6, 4665-4676.

  15. The effect of face-to-face or group education during pregnancy on sexual function of couples in Isfahan

    PubMed Central

    Bahadoran, Parvin; MohammadiMahdiabadzade, Maryam; Nasiri, Hamid; GholamiDehaghi, Ali

    2015-01-01

    Background: Pregnancy can be in conflict with sexual function which can be affected by physical and psychological changes during pregnancy. Therefore, comparison of the effect of face-to-face education with group education on sexual function during pregnancy in couples was the purpose of this research. Materials and Methods: In this quasi-experimental pre-test post-test study, 64 pregnant couples were selected and randomized in two groups in Isfahan. The data were collected using the triangulation of Female Sexual Function Index (FSFI), Brief form of Sexual Function Inventory (BSFI), and demographic characteristics questionnaires. The data were analyzed by independent t-test, paired t-test, Chi-square, analysis of covariance (ANCOVA), and analysis of variance (ANOVA) in SPSS. Results: No significant difference was found in the demographic characteristics between the two groups. Education was effective on sexual function in the two groups of women (P < 0.001), but no significant difference was found between the two groups (P = 0.61). Also, education was effective on sexual function of men in both the groups (P < 0.001) and there was a significant difference between the two groups (P = 0.003). Meanwhile, there was no significant difference between couples regarding the education (P = 0.104). Conclusions: The results of the study showed that type of education plays a role in improvement of sexual function in pregnancy. In addition, sex education is effective in prevention of sexual disorders in pregnancy. Therefore, having a special approach toward sex education classes during pregnancy is important for the health providers, particularly midwifery professionals. PMID:26457096

  16. Responses of phytoplankton functional groups to the hydrologic regime in the Daning River, a tributary of Three Gorges Reservoir, China.

    PubMed

    Zhu, Kongxian; Bi, Yonghong; Hu, Zhengyu

    2013-04-15

    Daning River is a deep tributary of Three Gorges Reservoir (TGR) in China, with water level fluctuations of 30 m annually. It was assumed that the hydrologic regime would be the main driving force in the self-assembling of the phytoplankton community in the river. In order to test this hypothesis, limnological study was performed monthly in the estuary, midstream and upstream of this tributary from May 2008 to April 2009. We identified 17 phytoplankton functional groups among 63 genera. These phytoplankton functional groups varied significantly, both seasonally and longitudinally. During the flood season (March-September), low water level and high inflows caused a marked increase in the turbidity, especially in the estuary and upstream, allowing functional group MP (the meroplanktonic diatoms) to dominate the phytoplankton community. Meanwhile, constant water level and high temperature led to the stability and thermal stratification in the midstream. These conditions resulted in a high phytoplankton biomass and the dominance of phytoplankton functional groups Y (Cryptomonas spp.) and Lo (motile Peridiniopsis niei and Peridinium) that were adapted to water stratification. During the dry season (October-February), although the inflows were low and water retention time was long, the thermal stratification was disrupted by the disturbance due to the impoundment of TGR, and the water column was deeply mixed. The phytoplankton biomass reduced and functional groups changed: group Lo declined, and group C (small diatom Cyclotella meneghiniana) increased in the estuary and midstream. Group Y replaced group MP to dominate the phytoplankton community in the upstream with the water becoming clear and stagnant. It could be deduced that the dynamics of phytoplankton in the Daning River were mainly influenced by hydrologic regime. PMID:23474263

  17. Functional Foods Programs Serve as a Vehicle to Provide Nutrition Education to Groups

    ERIC Educational Resources Information Center

    Cirignano, Sherri M.

    2011-01-01

    An increase in consumer interest in functional foods provides an opportunity for FCS educators to use this topic in Extension programming to promote current nutrition recommendations. The Functional Foods for Life Educational Programs (FFL) are a curriculum of six evidence-based mini-seminars that highlight specific functional foods that have the…

  18. Social categorization of social robots: anthropomorphism as a function of robot group membership.

    PubMed

    Eyssel, Friederike; Kuchenbrandt, Dieta

    2012-12-01

    Previous work on social categorization has shown that people often use cues such as a person's gender, age, or ethnicity to categorize and form impressions of others. The present research investigated effects of social category membership on the evaluation of humanoid robots. More specifically, participants rated a humanoid robot that either belonged to their in-group or to a national out-group with regard to anthropomorphism (e.g., mind attribution, warmth), psychological closeness, contact intentions, and design. We predicted that participants would show an in-group bias towards the robot that ostensibly belonged to their in-group--as indicated by its name and location of production. In line with our hypotheses, participants not only rated the in-group robot more favourably--importantly, they also anthropomorphized it more strongly than the out-group robot. Our findings thus document that people even apply social categorization processes and subsequent differential social evaluations to robots.

  19. Amino and Acetamide Functional Group Effects on the Ionization and Fragmentation of Sugar Chains in Positive-Ion Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Yamagaki, Tohru; Sugahara, Kohtaro; Watanabe, Takehiro

    2014-01-01

    To elucidate the influence of amino (-NH2) and acetamide (-NHCOCH3, -NAc) groups in sugar chains on their ionization and fragmentation, cycloamyloses (cyclodextrins, CyDs) and lacto-oligosaccharide are analyzed by MALDI TOF/TOF and ESI Q-TOF mass spectrometry. CyD derivatives substituted by amino or acetamide groups are ideal analytes to extract the function group effects, which are amino-CyD with one hexosamine (HexNH2) and acetamide-CyD with one N-acetyl hexosamine (HexNAc). Interestingly, the relative ion intensities and isotope-like patterns in their product ion spectra depend on the functional groups and ion forms of sugar chains. Consequently, the results indicate that a proton (H+) localizes on the amino group of the amino sugar, and that the proton (H+) induces their fragmentation. Sodium cation (Na+) attachment is independent from amino group and exerts no influence on their fragmentation patterns in amino group except for mono- and disaccharide fragment ions because there is the possibility of the reducing end effect. In contrast, a sodium cation localizes much more frequently on the acetamide group in acetamide-CyDs because the chemical species with HexNAc are stable. Thus, their ions with HexNAc are abundant. These results are consistent with the fragmentation of lacto-neo- N-tetraose and maltotetraose, suggesting that a sodium cation generally localizes much more frequently on the acetamide group in sugar chains.

  20. First Functional and Mutational Analysis of Group 3 N-Acetylneuraminate Lyases from Lactobacillus antri and Lactobacillus sakei 23K

    PubMed Central

    García-García, María Inmaculada; Gil-Ortiz, Fernando; García-Carmona, Francisco; Sánchez-Ferrer, Álvaro

    2014-01-01

    N-acetyl neuraminate lyases (NALs) catalyze the reversible aldol cleavage of N-acetyl neuraminic acid (Neu5Ac) to pyruvate and N-acetyl-D-mannosamine (ManNAc). Previous phylogenetic studies divided NALs into four different groups. Groups 1 and 2 have been well characterized at both kinetic and molecular levels, but no NAL from group 3 has been studied to date. In this work, a functional characterization of two group 3 members was performed using the recombinant NALs from Lactobacillus antri and Lactobacillus sakei 23K, revealing an optimal pH of between 6.0 and 7.0, low stability at basic pHs (>8.0), low optimal temperatures and, especially, low catalytic efficiency compared with their counterparts in group 1 and 2. The mutational analysis carried out showed that a plausible molecular reason for the low activity shown by Lactobacillus antri and Lactobacillus sakei 23k NALs compared with group 1 and 2 NALs could be the relatively small sugar-binding pocket they contain. A functional divergence analysis concluding that group 3 is more closely related to group 2 than to group 1. PMID:24817128

  1. Effect of group cognitive-behavioral therapy on the quality of life and social functioning of patients with mild depression

    PubMed Central

    ZHANG, Boyuan; DING, Xuefan; LU, Weihong; ZHAO, Jing; LV, Qinyu; YI, Zhenghui; ZHANG, Shaoping; CHEN, Yindi

    2016-01-01

    Background Several studies of moderate-to-severe depression have shown that combined treatment with individual cognitive behavioral therapy (CBT) and antidepressant medication is better than either CBT or antidepressants alone. Less research has focused on the outcomes of group-CBT and antidepressants in persons with mild depression. Aim Evaluate the effects of group-CBT in combination with antidepressants on the quality of life and social functioning of outpatients with mild depression. Methods We randomized 62 outpatients with mild depression into a control group (n=30) that received antidepressant medication for 12 weeks and an intervention group (n=32) that received antidepressants and group-CBT for 12 weeks; both groups were then continued on antidepressants alone for one year. Blinded evaluators used Chinese versions of the Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale, Social Disability Screening Schedule, Life Satisfaction Rating, Multidimensional Scale of Perceived Social Support, and Short Form Health Survey to assess participants after 12 weeks of treatment and at the end of one year of follow-up. Results Repeated measures analysis of variance showed that the depressive and anxiety symptoms of both groups improved significantly during treatment and that the improvement was greater in the CBT+antidepressant experimental group. Almost all of the social functioning, social support, and quality of life measures also showed significantly greater improvement in the CBT+antidepressant group than in the antidepressant-only group. Moreover, even after adjusting for differences in baseline demographic and clinical characteristics and for changes in the severity of depression and anxiety over time using an analysis of covariance, the greater improvement in the CBT+antidepressant group remained statistically significant both after the 12 weeks of group-CBT treatment and one year after the group CBT had ended. Conclusion Antidepressants alone or

  2. Effects of oxygen functional groups on the enhancement of the hydrogen spillover of Pd-doped activated carbon.

    PubMed

    Chung, Tsui-Yun; Tsao, Cheng-Si; Tseng, Hui-Ping; Chen, Chien-Hung; Yu, Ming-Sheng

    2015-03-01

    The hydrogen storage performance of Pd-doped oxidized activated carbon (Pd/AC-ox) with various oxygen contents or functional groups was investigated. The surface chemistry of the Pd/AC-ox sample was modified by treatment with hydrogen gas. Temperature-programmed desorption was performed to characterize the oxygen functional groups in each sample. In this study, low- and high-pressure hydrogen adsorption isotherm experiments were conducted using a static volumetric measurement at room temperature (RT) and pressures of up to 8 MPa. The results showed that increasing the oxygen content and functional groups on the surface of the Pd/AC-ox significantly improved the reversible RT hydrogen storage capacity due to the spillover effect. The hydrogen spillover enhancement factors at 0.12 MPa were greater than 100% for all samples. The hydrogen uptake of Pd/AC-ox1 at RT and 8 MPa with an oxygen content of 8.94 wt.% was 0.37 wt.%, which was 48% greater than that of Pd-free AC-ox (0.25 wt.%). In addition, the hydrogen uptake of Pd/AC-ox3 with lower oxygen contents demonstrates that the hydrogen spillover enhancement gradually disappears when the pressure is increased to more than 2 MPa (i.e., a transition from spillover to physisorption). The surface diffusion, or reversible adsorption, of the spiltover H atoms, which is enhanced by oxygen functional groups, was affected by a threshold amount of oxygen groups (such as hydroxyl groups). PMID:25490569

  3. Population dynamics: seasonal variation of phytoplankton functional groups in brazilian reservoirs (Billings and Guarapiranga, São Paulo).

    PubMed

    Gemelgo, M C P; Mucci, J L N; Navas-Pereira, D

    2009-11-01

    Phytoplankton may function as a 'sensor' of changes in aquatic environment and responds rapidly to such changes. In freshwaters, coexistence of species that have similar ecological requirements and show the same environmental requirements frequently occurs; such species groups are named functional groups. The use of phytoplankton functional groups to evaluate these changes has proven to be very useful and effective. Thus, the aim of this study was to evaluate the occurrence of functional groups of phytoplankton in two reservoirs (Billings and Guarapiranga) that supply water to millions of people in São Paulo city Metropolitan Area, southeastern Brazil. Surface water samples were collected monthly and physical, chemical and biological (quantitative and qualitative analyses of the phytoplankton) were performed. The highest biovolume (mm(3).L-1) of the descriptor species and functional groups were represented respectively by Anabaena circinalis Rabenh. (H1), Microcystis aeruginosa (Kützing) Kützing (L M/M) and Mougeotia sp. (T) in the Guarapiranga reservoir and Cylindrospermopsis raciborskii (Wolosz.) Seen. and Subba Raju (S N), Microcystis aeruginosa and M. panniformis Komárek et al. (L M/M), Planktothrix agardhii (Gom.) Anagn. and Komárek and P. cf. clathrata (Skuja) Anagn. and Komárek (S1) in the Billings reservoir. The environmental factors that most influenced the phytoplankton dynamics were water temperature, euphotic zone, turbidity, conductivity, pH, dissolved oxygen, nitrate and total phosphorous.

  4. Functions of an Adult Sickle Cell Group: Education, Task Orientation, and Support.

    ERIC Educational Resources Information Center

    Butler, Dennis J.; Beltran, Lou R.

    1993-01-01

    Reports on development of adult sickle cell support group and provides description of psychosocial factors most prevalent in patients' lives (anxiety about death, disruption of social support network, disability, dependence on pain medication, conflicts with health care providers). Notes that support group enhanced participants' knowledge about…

  5. Home Schooling Parent Support Groups in Kansas: A Naturalistic Inquiry into Their Concerns and Functions.

    ERIC Educational Resources Information Center

    Bishop, Celia

    This study investigated autonomous local home schooling parent support groups in Kansas. The home schooling movement in Kansas is an alternative educational entity whose membership has recently been increasing. Accompanying support groups have also increased in number. The purpose of this study was to conduct a naturalistic inquiry into the…

  6. Density functional study of hydrogen bond formation between methanol and organic molecules containing Cl, F, NH2, OH, and COOH functional groups.

    PubMed

    Kolev, Stefan K; St Petkov, Petko; Rangelov, Miroslav A; Vayssilov, Georgi N

    2011-12-01

    Various hydrogen-bonded complexes of methanol with different proton accepting and proton donating molecules containing Cl, F, NH(2), OH, OR, and COOH functional groups have been modeled using DFT with hybrid B3LYP and M05-2X functionals. The latter functional was found to provide more accurate estimates of the structural and thermodynamic parameters of the complexes of halides, amines, and alcohols. The characteristics of these complexes are influenced not only by the principle hydrogen bond of the methanol OH with the proton acceptor heteroatom, but also by additional hydrogen bonds of a C-H moiety with methanol oxygen as a proton acceptor. The contribution of the former hydrogen bond in the total binding enthalpy increases in the order chlorides < fluorides < alcohols < amines, while the contribution of the second type of hydrogen bond increases in the reverse order. A general correlation was found between the binding enthalpy of the complex and the electrostatic potential at the hydrogen center participating in the formation of the hydrogen bond. The calculated binding enthalpies of different complexes were used to clarify which functional groups can potentially form a hydrogen bond to the 2'-OH hydroxyl group in ribose, which is strong enough to block it from participation in the intramolecular catalytic activation of the peptide bond synthesis. Such blocking could result in inhibition of the protein biosynthesis in the living cell if the corresponding group is delivered as a part of a drug molecule in the vicinity of the active site in the ribosome. According to our results, such activity can be accomplished by secondary or tertiary amines, alkoxy groups, deprotonated carboxyl groups, and aliphatic fluorides, but not by the other modeled functional groups. PMID:21992409

  7. Synthesis, characterization, and biocompatibility of biodegradable hyperbranched polyglycerols from acid-cleavable ketal group functionalized initiators.

    PubMed

    Shenoi, Rajesh A; Lai, Benjamin F L; Kizhakkedathu, Jayachandran N

    2012-10-01

    Herein we report the synthesis of biodegradable hyperbranched polyglycerols (BHPGs) having acid-cleavable core structure by anionic ring-opening multibranching polymerization (ROMBP) of glycidol using initiators bearing dimethyl and cyclohexyl ketal groups. Five different multifunctional initiators carrying one to four ketal groups and two to four hydroxyl groups per molecule were synthesized. The hydroxyl carrying initiators containing one ketal group per molecule were synthesized from ethylene glycol. An alkyne-azide click reaction was used for synthesizing initiators containing multiple cyclohexyl ketal linkages and hydroxyl groups. The synthesized BHPGs exhibited monomodal molecular weight distributions and polydispersity in the range of 1.2 to 1.6, indicating the controlled nature of the polymerizations. The polymers were relatively stable at physiological pH but degraded at acidic pH values. The polymer degradation was dependent on the type of ketal structure present in the BHPG; polymers with cyclohexyl ketal groups degraded at much slower rates than those with dimethyl ketal groups at a given pH. Good control of polymer degradation was achieved under mild acidic conditions by changing the structure of ketal linkages. A precise control of the molecular weight of the degraded HPG was achieved by controlling the number of ketal groups within the core, as revealed from the gel permeation chromatography (GPC) analyses. The decrease in the polymer molecular weights upon degradation was correlated well with the number of ketal groups in their core structure. Our data support the suggestion that glycidol was polymerized uniformly from all hydroxyl groups of the initiators. BHPGs and their degradation products were highly biocompatible, as measured by blood coagulation, complement activation, platelet activation, and cell viability assays. The controlled degradation profiles of these polymers together with their excellent biocompatibility make them suitable for drug

  8. Process for depositing thin film layers onto surfaces modified with organic functional groups and products formed thereby

    DOEpatents

    Tarasevich, Barbara J.; Rieke, Peter C.

    1998-01-01

    A method is provided for producing a thin film product, comprising a first step in which an underlying substrate of a first material is provided. The underlying substrate includes a plurality of unmodified sites. The underlying substrate is then chemically modified wherein a plurality of organic functional groups are attached to a plurality of the unmodified sites. The arrangement and type of the functional group used can be selected for the purpose of controlling particular properties of the second material deposited. A thin film layer of at least one second material is then deposited onto the chemically modified underlying substrate. This can be accomplished by connecting the thin film to the underlying substrate by binding the thin film to the functional groups.

  9. Process for depositing thin film layers onto surfaces modified with organic functional groups and products formed thereby

    DOEpatents

    Tarasevich, B.J.; Rieke, P.C.

    1998-06-02

    A method is provided for producing a thin film product, comprising a first step in which an underlying substrate of a first material is provided. The underlying substrate includes a plurality of unmodified sites. The underlying substrate is then chemically modified wherein a plurality of organic functional groups are attached to a plurality of the unmodified sites. The arrangement and type of the functional group used can be selected for the purpose of controlling particular properties of the second material deposited. A thin film layer of at least one second material is then deposited onto the chemically modified underlying substrate. This can be accomplished by connecting the thin film to the underlying substrate by binding the thin film to the functional groups. 5 figs.

  10. 14 CFR Section 10 - Functional Classification-Operating Expenses of Group I Air Carriers

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... otherwise provided for in functions 5100 Flying Operations, 5400 Maintenance and 7000 Depreciation and..., as well as losses in serviceability caused by obsolescence, supersession, discoveries, change...

  11. Functional renormalization-group approaches, one-particle (irreducible) reducible with respect to local Green’s functions, with dynamical mean-field theory as a starting point

    SciTech Connect

    Katanin, A. A.

    2015-06-15

    We consider formulations of the functional renormalization-group (fRG) flow for correlated electronic systems with the dynamical mean-field theory as a starting point. We classify the corresponding renormalization-group schemes into those neglecting one-particle irreducible six-point vertices (with respect to the local Green’s functions) and neglecting one-particle reducible six-point vertices. The former class is represented by the recently introduced DMF{sup 2}RG approach [31], but also by the scale-dependent generalization of the one-particle irreducible representation (with respect to local Green’s functions, 1PI-LGF) of the generating functional [20]. The second class is represented by the fRG flow within the dual fermion approach [16, 32]. We compare formulations of the fRG approach in each of these cases and suggest their further application to study 2D systems within the Hubbard model.

  12. Plant Diversity Surpasses Plant Functional Groups and Plant Productivity as Driver of Soil Biota in the Long Term

    PubMed Central

    Eisenhauer, Nico; Milcu, Alexandru; Sabais, Alexander C. W.; Bessler, Holger; Brenner, Johanna; Engels, Christof; Klarner, Bernhard; Maraun, Mark; Partsch, Stephan; Roscher, Christiane; Schonert, Felix; Temperton, Vicky M.; Thomisch, Karolin; Weigelt, Alexandra; Weisser, Wolfgang W.; Scheu, Stefan

    2011-01-01

    Background One of the most significant consequences of contemporary global change is the rapid decline of biodiversity in many ecosystems. Knowledge of the consequences of biodiversity loss in terrestrial ecosystems is largely restricted to single ecosystem functions. Impacts of key plant functional groups on soil biota are considered to be more important than those of plant diversity; however, current knowledge mainly relies on short-term experiments. Methodology/Principal Findings We studied changes in the impacts of plant diversity and presence of key functional groups on soil biota by investigating the performance of soil microorganisms and soil fauna two, four and six years after the establishment of model grasslands. The results indicate that temporal changes of plant community effects depend on the trophic affiliation of soil animals: plant diversity effects on decomposers only occurred after six years, changed little in herbivores, but occurred in predators after two years. The results suggest that plant diversity, in terms of species and functional group richness, is the most important plant community property affecting soil biota, exceeding the relevance of plant above- and belowground productivity and the presence of key plant functional groups, i.e. grasses and legumes, with the relevance of the latter decreasing in time. Conclusions/Significance Plant diversity effects on biota are not only due to the presence of key plant functional groups or plant productivity highlighting the importance of diverse and high-quality plant derived resources, and supporting the validity of the singular hypothesis for soil biota. Our results demonstrate that in the long term plant diversity essentially drives the performance of soil biota questioning the paradigm that belowground communities are not affected by plant diversity and reinforcing the importance of biodiversity for ecosystem functioning. PMID:21249208

  13. Defining Planktonic Protist Functional Groups on Mechanisms for Energy and Nutrient Acquisition: Incorporation of Diverse Mixotrophic Strategies.

    PubMed

    Mitra, Aditee; Flynn, Kevin J; Tillmann, Urban; Raven, John A; Caron, David; Stoecker, Diane K; Not, Fabrice; Hansen, Per J; Hallegraeff, Gustaaf; Sanders, Robert; Wilken, Susanne; McManus, George; Johnson, Mathew; Pitta, Paraskevi; Våge, Selina; Berge, Terje; Calbet, Albert; Thingstad, Frede; Jeong, Hae Jin; Burkholder, JoAnn; Glibert, Patricia M; Granéli, Edna; Lundgren, Veronica

    2016-04-01

    Arranging organisms into functional groups aids ecological research by grouping organisms (irrespective of phylogenetic origin) that interact with environmental factors in similar ways. Planktonic protists traditionally have been split between photoautotrophic "phytoplankton" and phagotrophic "microzooplankton". However, there is a growing recognition of the importance of mixotrophy in euphotic aquatic systems, where many protists often combine photoautotrophic and phagotrophic modes of nutrition. Such organisms do not align with the traditional dichotomy of phytoplankton and microzooplankton. To reflect this understanding, we propose a new functional grouping of planktonic protists in an eco-physiological context: (i) phagoheterotrophs lacking phototrophic capacity, (ii) photoautotrophs lacking phagotrophic capacity, (iii) constitutive mixotrophs (CMs) as phagotrophs with an inherent capacity for phototrophy, and (iv) non-constitutive mixotrophs (NCMs) that acquire their phototrophic capacity by ingesting specific (SNCM) or general non-specific (GNCM) prey. For the first time, we incorporate these functional groups within a foodweb structure and show, using model outputs, that there is scope for significant changes in trophic dynamics depending on the protist functional type description. Accordingly, to better reflect the role of mixotrophy, we recommend that as important tools for explanatory and predictive research, aquatic food-web and biogeochemical models need to redefine the protist groups within their frameworks. PMID:26927496

  14. Defining Planktonic Protist Functional Groups on Mechanisms for Energy and Nutrient Acquisition: Incorporation of Diverse Mixotrophic Strategies.

    PubMed

    Mitra, Aditee; Flynn, Kevin J; Tillmann, Urban; Raven, John A; Caron, David; Stoecker, Diane K; Not, Fabrice; Hansen, Per J; Hallegraeff, Gustaaf; Sanders, Robert; Wilken, Susanne; McManus, George; Johnson, Mathew; Pitta, Paraskevi; Våge, Selina; Berge, Terje; Calbet, Albert; Thingstad, Frede; Jeong, Hae Jin; Burkholder, JoAnn; Glibert, Patricia M; Granéli, Edna; Lundgren, Veronica

    2016-04-01

    Arranging organisms into functional groups aids ecological research by grouping organisms (irrespective of phylogenetic origin) that interact with environmental factors in similar ways. Planktonic protists traditionally have been split between photoautotrophic "phytoplankton" and phagotrophic "microzooplankton". However, there is a growing recognition of the importance of mixotrophy in euphotic aquatic systems, where many protists often combine photoautotrophic and phagotrophic modes of nutrition. Such organisms do not align with the traditional dichotomy of phytoplankton and microzooplankton. To reflect this understanding, we propose a new functional grouping of planktonic protists in an eco-physiological context: (i) phagoheterotrophs lacking phototrophic capacity, (ii) photoautotrophs lacking phagotrophic capacity, (iii) constitutive mixotrophs (CMs) as phagotrophs with an inherent capacity for phototrophy, and (iv) non-constitutive mixotrophs (NCMs) that acquire their phototrophic capacity by ingesting specific (SNCM) or general non-specific (GNCM) prey. For the first time, we incorporate these functional groups within a foodweb structure and show, using model outputs, that there is scope for significant changes in trophic dynamics depending on the protist functional type description. Accordingly, to better reflect the role of mixotrophy, we recommend that as important tools for explanatory and predictive research, aquatic food-web and biogeochemical models need to redefine the protist groups within their frameworks.

  15. Syntheses and Structures of Functionalized [9]Cycloparaphenylenes as Carbon Nanohoops Bearing Carbomethoxy and N-Phenylphthalimido Groups.

    PubMed

    Li, Shuangjiang; Huang, Changfeng; Thakellapalli, Haresh; Farajidizaji, Behzad; Popp, Brian V; Petersen, Jeffrey L; Wang, Kung K

    2016-05-01

    Functionalized [9]cycloparaphenylenes ([9]CPPs) bearing nine aromatic units in the macrocyclic structures were synthesized. The macrocyclic structures were substituted with carbomethoxy or N-phenylphthalimido groups. The Diels-Alder reaction of (E,E)-1,4-bis(4-bromophenyl)-1,3-butadiene or a related diene with dimethyl acetylenedicarboxylate followed by the nickel-mediated homocoupling reactions and oxidative aromatization produced the functionalized [9]CPPs. Treatment of a resultant [9]CPP with aniline or 1,4-diaminobenzene gave the corresponding N-phenylphthalimides. The X-ray structure of a [9]CPP bearing six carbomethoxy groups was obtained. PMID:27101316

  16. Doping Level of Boron-Doped Diamond Electrodes Controls the Grafting Density of Functional Groups for DNA Assays.

    PubMed

    Švorc, Ĺubomír; Jambrec, Daliborka; Vojs, Marian; Barwe, Stefan; Clausmeyer, Jan; Michniak, Pavol; Marton, Marián; Schuhmann, Wolfgang

    2015-09-01

    The impact of different doping levels of boron-doped diamond on the surface functionalization was investigated by means of electrochemical reduction of aryldiazonium salts. The grafting efficiency of 4-nitrophenyl groups increased with the boron levels (B/C ratio from 0 to 20,000 ppm). Controlled grafting of nitrophenyldiazonium was used to adjust the amount of immobilized single-stranded DNA strands at the surface and further on the hybridization yield in dependence on the boron doping level. The grafted nitro functions were electrochemically reduced to the amine moieties. Subsequent functionalization with a succinic acid introduced carboxyl groups for subsequent binding of an amino-terminated DNA probe. DNA hybridization significantly depends on the probe density which is in turn dependent on the boron doping level. The proposed approach opens new insights for the design and control of doped diamond surface functionalization for the construction of DNA hybridization assays.

  17. Extracting Intrinsic Functional Networks with Feature-Based Group Independent Component Analysis

    ERIC Educational Resources Information Center

    Calhoun, Vince D.; Allen, Elena

    2013-01-01

    There is increasing use of functional imaging data to understand the macro-connectome of the human brain. Of particular interest is the structure and function of intrinsic networks (regions exhibiting temporally coherent activity both at rest and while a task is being performed), which account for a significant portion of the variance in…

  18. Effects of stocking rates on functional group diversity and forage quality in rangeland of Qilian Mountain, China.

    PubMed

    Zhanq, Yan; Chen, Xianjiang; Cheng, Yunxiang; Chang, Shenghua; Hou, Fujiang

    2015-07-01

    The present study aimed at investigating a balance between environment and livestock grazing, through identifying appropriate stocking rate in rangeland with highest biodiversity and forage quality. The experiment was carried out to determine the effects of six stocking rates on Shannon Weiner index of functional group diversity and nutritive value and relationship between them in the edge of the Tibetan plateau of China. The results showed that abundance of functional group diversity indices were significantly influenced by stocking rates (p < 0.05) and the highest appeared in 2.5 and 2.6 animal month unit (AMU) ha(-1)'. There were significant differences in forage content of nitrogen (N), water-soluble carbohydrate (WSC), neutral detergent fiber (NDF) and acid detergent fiber (ADF) under stocking rates (p<0.05). There were higher N and WSC content but lower NDF and ADF content under 2.5 and 2.6 AMU ha(-1) than other stocking rates. Positive relationship was found between all functional group diversity indices and N and WSC content of community but negative relationship between all functional group diversity indices and NDF and ADF content of community. All the results represented that moderate control of stocking rates was an effective management measure to protect functional diversity, improve forage quality and sustain rangeland health. PMID:26387344

  19. Thermal-nutritional regulation of functional groups in running water ecosystems. Technical progress report, October 1, 1978-November 1, 1980

    SciTech Connect

    Cummins, K.W.

    1980-11-01

    The research encompassed three general areas: (1) characterization of stream macroinvertebrate functional feeding groups (shredders, collectors, scrapers, and predators) based on morphological and behavioral adaptations and food-source-specific growth responses of selected species; (2) demonstration of the relative importance of temperature and food quality (in which maximum quality is defined as that producing the most growth) in controlling growth rate and survivorship of stream functional groups; and (3) derivation and refinement of conceptual and quantitative models of stream ecosystem structure and function, with particular emphasis on detrital processing. Verification of the functional group concept as a tool for assessing and predicting is reflected in alterations of the relative dominance of various functional groups. Food quality can strongly influence the growth rates of shredders, collectors and scrapers and override the effects of temperature in a number of cases. Gathering collectors may select food particles by size (or at least be restricted to a limited portion of the total range available) but representative species do not appear to select for quality.

  20. Effects of stocking rates on functional group diversity and forage quality in rangeland of Qilian Mountain, China.

    PubMed

    Zhanq, Yan; Chen, Xianjiang; Cheng, Yunxiang; Chang, Shenghua; Hou, Fujiang

    2015-07-01

    The present study aimed at investigating a balance between environment and livestock grazing, through identifying appropriate stocking rate in rangeland with highest biodiversity and forage quality. The experiment was carried out to determine the effects of six stocking rates on Shannon Weiner index of functional group diversity and nutritive value and relationship between them in the edge of the Tibetan plateau of China. The results showed that abundance of functional group diversity indices were significantly influenced by stocking rates (p < 0.05) and the highest appeared in 2.5 and 2.6 animal month unit (AMU) ha(-1)'. There were significant differences in forage content of nitrogen (N), water-soluble carbohydrate (WSC), neutral detergent fiber (NDF) and acid detergent fiber (ADF) under stocking rates (p<0.05). There were higher N and WSC content but lower NDF and ADF content under 2.5 and 2.6 AMU ha(-1) than other stocking rates. Positive relationship was found between all functional group diversity indices and N and WSC content of community but negative relationship between all functional group diversity indices and NDF and ADF content of community. All the results represented that moderate control of stocking rates was an effective management measure to protect functional diversity, improve forage quality and sustain rangeland health.

  1. The hypothesis on function of glycosphingolipids and ABO blood groups revisited.

    PubMed

    Kościelak, Jerzy

    2012-06-01

    Twenty-five years ago the author proposed new ideas of glycoprotein (GPs) and glycosphingolipid (GSLs) functions at the cell membrane. The GPs, apart from their glycan carrying capacity, were assumed to have specific, protein associated, functions. In contrast, GSLs such as those of globo and neolacto/lacto series, were considered to be energetically cheap membrane packing substances, filling in membrane spaces not covered with functional GPs. The terminal carbohydrate structures of the neolacto/lacto GSLs, i.e., sialic acid residues and ABH glycotopes, were postulated to have either regulatory or protective functions, respectively. A special active role was ascribed to terminal β-galactosyl residues of GSLs and GPs. Gangliosides were considered to be functional GSLs. In the present review the author discusses these old ideas in context of the contemporary knowledge and comes to the conclusion that they have not aged.

  2. Bi-invariant functions on the group of transformations leaving a measure quasi-invariant

    SciTech Connect

    Neretin, Yu A

    2014-09-30

    Let Gms be the group of transformations of a Lebesgue space leaving the measure quasi-invariant. Let Ams be a subgroup of it consisting of transformations preserving the measure. We describe canonical forms of double cosets of Gms by the subgroup Ams and show that all continuous Ams-bi-invariant functions on Gms are functionals of the distribution of a Radon-Nikodym derivative. Bibliography: 14 titles.

  3. Frequency perception of individual and group successes as a function of competition, coaction, and isolation.

    PubMed

    Janssens, L; Nuttin, J R

    1976-11-01

    The frequency perception of successful and unsuccessful outcomes obtained in serial tasks was investigated in two experiments. Subjects were assigned to serial tasks in which the outcome stimuli ("right" and "wrong") immediately followed subjects' responses to each task item. Subjects' perceptual judgment about the number of "rights and wrongs" obtained was requested at the end of the serial task (incidental event perception). In Experiment 1, subjects performing in groups of four were compared with individual performers both in competing and noncompeting (coacting) conditions. In Experiment 2, the influence of verbal communication and competition versus isolation was examined. Significant and predicted differences in frequeency perception were found (a) in group performers as compared with individual performers, (b) in groups with verbal communication as compared with groups without verbal communication, and (c) in competing groups as compared with noncompeting, especially isolated, groups. The frequency perception of success is discussed in the context of impression formation processes, and its impact on person perception and learning is mentioned. A tentative explanation in terms of affective and cognitive processes related to social interaction is submitted. PMID:993983

  4. Comparative genomics and functional analysis of the 936 group of lactococcal Siphoviridae phages

    PubMed Central

    Murphy, James; Bottacini, Francesca; Mahony, Jennifer; Kelleher, Philip; Neve, Horst; Zomer, Aldert; Nauta, Arjen; van Sinderen, Douwe

    2016-01-01

    Genome sequencing and comparative analysis of bacteriophage collections has greatly enhanced our understanding regarding their prevalence, phage-host interactions as well as the overall biodiversity of their genomes. This knowledge is very relevant to phages infecting Lactococcus lactis, since they constitute a significant risk factor for dairy fermentations. Of the eighty four lactococcal phage genomes currently available, fifty five belong to the so-called 936 group, the most prevalent of the ten currently recognized lactococcal phage groups. Here, we report the genetic characteristics of a new collection of 936 group phages. By combining these genomes to those sequenced previously we determined the core and variable elements of the 936 genome. Genomic variation occurs across the 936 phage genome, such as genetic elements that (i) lead to a +1 translational frameshift resulting in the formation of additional structures on the phage tail, (ii) specify a double neck passage structure, and (iii) encode packaging module-associated methylases. Hierarchical clustering of the gene complement of the 936 group phages and nucleotide alignments allowed grouping of the ninety 936 group phages into distinct clusters, which in general appear to correspond with their geographical origin. PMID:26892066

  5. The use of discontinuities and functional groups to assess relative resilience in complex systems

    USGS Publications Warehouse

    Allen, C.R.; Gunderson, Lance; Johnson, A.R.

    2005-01-01

    It is evident when the resilience of a system has been exceeded and the system qualitatively changed. However, it is not clear how to measure resilience in a system prior to the demonstration that the capacity for resilient response has been exceeded. We argue that self-organizing human and natural systems are structured by a relatively small set of processes operating across scales in time and space. These structuring processes should generate a discontinuous distribution of structures and frequencies, where discontinuities mark the transition from one scale to another. Resilience is not driven by the identity of elements of a system, but rather by the functions those elements provide, and their distribution within and across scales. A self-organizing system that is resilient should maintain patterns of function within and across scales despite the turnover of specific elements (for example, species, cities). However, the loss of functions, or a decrease in functional representation at certain scales will decrease system resilience. It follows that some distributions of function should be more resilient than others. We propose that the determination of discontinuities, and the quantification of function both within and across scales, produce relative measures of resilience in ecological and other systems. We describe a set of methods to assess the relative resilience of a system based upon the determination of discontinuities and the quantification of the distribution of functions in relation to those discontinuities. ?? 2005 Springer Science+Business Media, Inc.

  6. Liking is not the opposite of disliking: the functional separability of positive and negative attitudes toward minority groups.

    PubMed

    Pittinsky, Todd L; Rosenthal, Seth A; Montoya, R Matthew

    2011-04-01

    Two studies tested the hypotheses that positive and negative attitudes toward minority groups are not interchangeable in predicting positive versus negative behaviors toward those groups. In Study 1, positive attitudes about Latinos were a better predictor of a positive behavior toward Latinos than were negative attitudes or stereotyped positive attitudes. In Study 2, positive attitudes about African Americans were a better predictor of positive behavioral intentions toward that group than were negative attitudes, whereas negative attitudes were better predictors of negative behavioral intentions than were positive attitudes. Taken together, the studies support the perspective that positive and negative attitudes toward minority groups are theoretically and functionally distinct constructs. We conclude that it is important to measure both positive and negative attitudes to understand and predict behaviors toward minority groups.

  7. Integrated Analysis and Visualization of Group Differences in Structural and Functional Brain Connectivity: Applications in Typical Ageing and Schizophrenia.

    PubMed

    Langen, Carolyn D; White, Tonya; Ikram, M Arfan; Vernooij, Meike W; Niessen, Wiro J

    2015-01-01

    Structural and functional brain connectivity are increasingly used to identify and analyze group differences in studies of brain disease. This study presents methods to analyze uni- and bi-modal brain connectivity and evaluate their ability to identify differences. Novel visualizations of significantly different connections comparing multiple metrics are presented. On the global level, "bi-modal comparison plots" show the distribution of uni- and bi-modal group differences and the relationship between structure and function. Differences between brain lobes are visualized using "worm plots". Group differences in connections are examined with an existing visualization, the "connectogram". These visualizations were evaluated in two proof-of-concept studies: (1) middle-aged versus elderly subjects; and (2) patients with schizophrenia versus controls. Each included two measures derived from diffusion weighted images and two from functional magnetic resonance images. The structural measures were minimum cost path between two anatomical regions according to the "Statistical Analysis of Minimum cost path based Structural Connectivity" method and the average fractional anisotropy along the fiber. The functional measures were Pearson's correlation and partial correlation of mean regional time series. The relationship between structure and function was similar in both studies. Uni-modal group differences varied greatly between connectivity types. Group differences were identified in both studies globally, within brain lobes and between regions. In the aging study, minimum cost path was highly effective in identifying group differences on all levels; fractional anisotropy and mean correlation showed smaller differences on the brain lobe and regional levels. In the schizophrenia study, minimum cost path and fractional anisotropy showed differences on the global level and within brain lobes; mean correlation showed small differences on the lobe level. Only fractional anisotropy

  8. Integrated Analysis and Visualization of Group Differences in Structural and Functional Brain Connectivity: Applications in Typical Ageing and Schizophrenia.

    PubMed

    Langen, Carolyn D; White, Tonya; Ikram, M Arfan; Vernooij, Meike W; Niessen, Wiro J

    2015-01-01

    Structural and functional brain connectivity are increasingly used to identify and analyze group differences in studies of brain disease. This study presents methods to analyze uni- and bi-modal brain connectivity and evaluate their ability to identify differences. Novel visualizations of significantly different connections comparing multiple metrics are presented. On the global level, "bi-modal comparison plots" show the distribution of uni- and bi-modal group differences and the relationship between structure and function. Differences between brain lobes are visualized using "worm plots". Group differences in connections are examined with an existing visualization, the "connectogram". These visualizations were evaluated in two proof-of-concept studies: (1) middle-aged versus elderly subjects; and (2) patients with schizophrenia versus controls. Each included two measures derived from diffusion weighted images and two from functional magnetic resonance images. The structural measures were minimum cost path between two anatomical regions according to the "Statistical Analysis of Minimum cost path based Structural Connectivity" method and the average fractional anisotropy along the fiber. The functional measures were Pearson's correlation and partial correlation of mean regional time series. The relationship between structure and function was similar in both studies. Uni-modal group differences varied greatly between connectivity types. Group differences were identified in both studies globally, within brain lobes and between regions. In the aging study, minimum cost path was highly effective in identifying group differences on all levels; fractional anisotropy and mean correlation showed smaller differences on the brain lobe and regional levels. In the schizophrenia study, minimum cost path and fractional anisotropy showed differences on the global level and within brain lobes; mean correlation showed small differences on the lobe level. Only fractional anisotropy

  9. Integrated Analysis and Visualization of Group Differences in Structural and Functional Brain Connectivity: Applications in Typical Ageing and Schizophrenia

    PubMed Central

    Langen, Carolyn D.; Ikram, M. Arfan; Vernooij, Meike W.

    2015-01-01

    Structural and functional brain connectivity are increasingly used to identify and analyze group differences in studies of brain disease. This study presents methods to analyze uni- and bi-modal brain connectivity and evaluate their ability to identify differences. Novel visualizations of significantly different connections comparing multiple metrics are presented. On the global level, “bi-modal comparison plots” show the distribution of uni- and bi-modal group differences and the relationship between structure and function. Differences between brain lobes are visualized using “worm plots”. Group differences in connections are examined with an existing visualization, the “connectogram”. These visualizations were evaluated in two proof-of-concept studies: (1) middle-aged versus elderly subjects; and (2) patients with schizophrenia versus controls. Each included two measures derived from diffusion weighted images and two from functional magnetic resonance images. The structural measures were minimum cost path between two anatomical regions according to the “Statistical Analysis of Minimum cost path based Structural Connectivity” method and the average fractional anisotropy along the fiber. The functional measures were Pearson’s correlation and partial correlation of mean regional time series. The relationship between structure and function was similar in both studies. Uni-modal group differences varied greatly between connectivity types. Group differences were identified in both studies globally, within brain lobes and between regions. In the aging study, minimum cost path was highly effective in identifying group differences on all levels; fractional anisotropy and mean correlation showed smaller differences on the brain lobe and regional levels. In the schizophrenia study, minimum cost path and fractional anisotropy showed differences on the global level and within brain lobes; mean correlation showed small differences on the lobe level. Only

  10. Chiroptical properties of an alternatingly functionalized cellotriose bearing two porphyrin groups

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternatingly functionalized cellulose molecules have potential applications in optoelectronics and molecular receptors. For example, cellulose-based solar cells have been proposed. As a prototype for such molecules, the trisaccharide fragment of cellulose was modified by attachment of porphyrin gro...

  11. A function for binaural integration in auditory grouping and segregation in the inferior colliculus.

    PubMed

    Nakamoto, Kyle T; Shackleton, Trevor M; Magezi, David A; Palmer, Alan R

    2015-03-15

    Responses of neurons to binaural, harmonic complex stimuli in urethane-anesthetized guinea pig inferior colliculus (IC) are reported. To assess the binaural integration of harmonicity cues for sound segregation and grouping, responses were measured to harmonic complexes with different fundamental frequencies presented to each ear. Simultaneously gated harmonic stimuli with fundamental frequencies of 125 Hz and 145 Hz were presented to the left and right ears, respectively, and recordings made from 96 neurons with characteristic frequencies >2 kHz in the central nucleus of the IC. Of these units, 70 responded continuously throughout the stimulus and were excited by the stimulus at the contralateral ear. The stimulus at the ipsilateral ear excited (EE: 14%; 10/70), inhibited (EI: 33%; 23/70), or had no significant effect (EO: 53%; 37/70), defined by the effect on firing rate. The neurons phase locked to the temporal envelope at each ear to varying degrees depending on signal level. Many of the cells (predominantly EO) were dominated by the response to the contralateral stimulus. Another group (predominantly EI) synchronized to the contralateral stimulus and were suppressed by the ipsilateral stimulus in a phasic manner. A third group synchronized to the stimuli at both ears (predominantly EE). Finally, a group only responded when the waveform peaks from each ear coincided. We conclude that these groups of neurons represent different "streams" of information but exhibit modifications of the response rather than encoding a feature of the stimulus, like pitch. PMID:25540219

  12. Functionalization of C(sp3)–H Bonds Using a Transient Directing Group

    PubMed Central

    Zhang, Fang-Lin; Hong, Kai; Li, Tuan-Jie; Park, Hojoon; Yu, Jin-Quan

    2016-01-01

    Proximity-driven metalation has been extensively exploited to achieve reactivity and selectivity in C–H bond activation. Despite the substantial improvement in developing more efficient and practical directing groups, their stoichiometric installation and removal limit efficiency and often applicability as well. Herein, we report the development of an amino acid reagent that reversibly reacts with aldehydes and ketones in situ via imine formation to serve as a transient directing group for activation of inert C–H bonds. Arylation of a wide range of aldehydes and ketones at the β- or γ-positions proceeds in the presence of a Pd catalyst and a catalytic amount of amino acid. The feasibility of achieving enantioselective C–H activation reactions using a chiral amino acid as the transient directing group is also demonstrated. PMID:26816374

  13. Organic chemistry. Functionalization of C(sp3)-H bonds using a transient directing group.

    PubMed

    Zhang, Fang-Lin; Hong, Kai; Li, Tuan-Jie; Park, Hojoon; Yu, Jin-Quan

    2016-01-15

    Proximity-driven metalation has been extensively exploited to achieve reactivity and selectivity in carbon-hydrogen (C-H) bond activation. Despite the substantial improvement in developing more efficient and practical directing groups, their stoichiometric installation and removal limit efficiency and, often, applicability as well. Here we report the development of an amino acid reagent that reversibly reacts with aldehydes and ketones in situ via imine formation to serve as a transient directing group for activation of inert C-H bonds. Arylation of a wide range of aldehydes and ketones at the β or γ positions proceeds in the presence of a palladium catalyst and a catalytic amount of amino acid. The feasibility of achieving enantioselective C-H activation reactions using a chiral amino acid as the transient directing group is also demonstrated.

  14. Influence of methyl functional groups on the stability of cubane carbon cage

    NASA Astrophysics Data System (ADS)

    Katin, Konstantin P.; Prudkovskiy, Vladimir S.; Maslov, Mikhail M.

    2016-07-01

    We present a quantum-chemical study to elucidate the structure, energetics and stability of isolated polymethylcubane molecules C8H8-q(CH3)q. The results obtained by means of originally developed nonorthogonal tight-binding approach are in good agreement with the existed experimental data for solid octamethylcubane C8(CH3)8. The isomerization mechanisms for polymethylcubane family are studied in detail and the minimum energy barriers' heights preventing the decomposition are calculated. The temperature dependence of octamethylcubane molecule lifetime to the decomposition moment was determined by direct molecular dynamics simulation. It is shown that methyl groups destabilize the cubic carbon cage, but less than nitro groups.

  15. Low-frequency group exercise improved the motor functions of community-dwelling elderly people in a rural area when combined with home exercise with self-monitoring.

    PubMed

    Matsubayashi, Yoshito; Asakawa, Yasuyoshi; Yamaguchi, Haruyasu

    2016-01-01

    [Purpose] This study examined whether low-frequency group exercise improved the motor functions of community-dwelling elderly people in a rural area when combined with home exercise with self-monitoring. [Subjects] The subjects were community-dwelling elderly people in a rural area of Japan. [Methods] One group (n = 50) performed group exercise combined with home exercise with self-monitoring. Another group (n = 37) performed group exercise only. Low-frequency group exercise (warm-up, exercises for motor functions, and cool-down) was performed in seven 40 to 70-minute sessions over 9 weeks by both groups. Five items of motor functions were assessed before and after the intervention. [Results] Significant interactions were observed between groups and assessment times for all motor functions. Improvements in motor functions were significantly greater in the group that performed group exercise combined with home exercise with self-monitoring than in the group that performed group exercise only. Post-hoc comparisons revealed significant differences in 3 items of motor functions. No significant improvements were observed in motor functions in the group that performed group exercise only. [Conclusions] Group exercise combined with home exercise with self-monitoring improved motor functions in the setting of low-frequency group exercise for community-dwelling elderly people in a rural area. PMID:27065520

  16. Assessing the temporal stability of surface functional groups introduced by plasma treatments on the outer shells of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Merenda, Andrea; Ligneris, Elise Des; Sears, Kallista; Chaffraix, Thomas; Magniez, Kevin; Cornu, David; Schütz, Jürg A.; Dumée, Ludovic F.

    2016-08-01

    Plasma treatments are emerging as superior efficiency treatment for high surface to volume ratio materials to tune functional group densities and alter crystallinity due to their ability to interact with matter at the nanoscale. The purpose of this study is to assess for the first time the long term stability of surface functional groups introduced across the surface of carbon nanotube materials for a series of oxidative, reductive and neutral plasma treatment conditions. Both plasma duration dose matrix based exposures and time decay experiments, whereby the surface energy of the materials was evaluated periodically over a one-month period, were carried out. Although only few morphological changes across the graphitic planes of the carbon nanotubes were found under the uniform plasma treatment conditions, the time dependence of pertinent work functions, supported by Raman analysis, suggested that the density of polar groups decreased non-linearly over time prior to reaching saturation from 7 days post treatment. This work provides critical considerations on the understanding of the stability of functional groups introduced across high specific surface area nano-materials used for the design of nano-composites, adsorptive or separation systems, or sensing materials and where interfacial interactions are key to the final materials performance.

  17. MODELING THE DYNAMICS OF THREE FUNCTIONAL GROUPS OF MACROALGAE IN TROPICAL SEAGRASS HABITATS. (R828677C004)

    EPA Science Inventory

    A model of three functional groups of macroalgae, drift algae, rhizophytic calcareous algae, and seagrass epiphytes, was developed to complement an existing seagrass production model for tropical habitats dominated by Thalassia testudinum (Turtle-grass). The current modeling e...

  18. Synthesis of Heterocycles Through Classical Ugi and Passerini Reactions Followed by Secondary Transformations Involving One or Two Additional Functional Groups

    NASA Astrophysics Data System (ADS)

    Banfi, Luca; Basso, Andrea; Riva, Renata

    The combination of classical isocyanide-based multicomponent reactions (Ugi and Passerini) with a variety of post-condensation transformations, which take advantage of suitably positioned additional functional groups, allows the straightforward synthesis, often in 1-2 synthetic steps, of many diverse nitrogen-containing heterocycles. This review will cover all the applications of this strategy reported to date (September 2009).

  19. The Ethnic Identity, Other-Group Attitudes, and Psychosocial Functioning of Asian American Emerging Adults from Two Contexts

    ERIC Educational Resources Information Center

    Juang, Linda P.; Nguyen, Huong H.; Lin, Yunghui

    2006-01-01

    Drawing from two samples of Asian American emerging adults, one in an ethnically concentrated context (n = 108) and the other in an ethnically-dispersed, mainly White context (n = 153), we examined (a) how ethnic identity and other-group attitudes were related to psychosocial functioning (i.e., depression, self-esteem, and connectedness to…

  20. Mapping functional group free energy patterns at protein occluded sites: nuclear receptors and G-protein coupled receptors.

    PubMed

    Lakkaraju, Sirish Kaushik; Yu, Wenbo; Raman, E Prabhu; Hershfeld, Alena V; Fang, Lei; Deshpande, Deepak A; MacKerell, Alexander D

    2015-03-23

    Occluded ligand-binding pockets (LBP) such as those found in nuclear receptors (NR) and G-protein coupled receptors (GPCR) represent a significant opportunity and challenge for computer-aided drug design. To determine free energies maps of functional groups of these LBPs, a Grand-Canonical Monte Carlo/Molecular Dynamics (GCMC/MD) strategy is combined with the Site Identification by Ligand Competitive Saturation (SILCS) methodology. SILCS-GCMC/MD is shown to map functional group affinity patterns that recapitulate locations of functional groups across diverse classes of ligands in the LBPs of the androgen (AR) and peroxisome proliferator-activated-γ (PPARγ) NRs and the metabotropic glutamate (mGluR) and β2-adreneric (β2AR) GPCRs. Inclusion of protein flexibility identifies regions of the binding pockets not accessible in crystal conformations and allows for better quantitative estimates of relative ligand binding affinities in all the proteins tested. Differences in functional group requirements of the active and inactive states of the β2AR LBP were used in virtual screening to identify high efficacy agonists targeting β2AR in Airway Smooth Muscle (ASM) cells. Seven of the 15 selected ligands were found to effect ASM relaxation representing a 46% hit rate. Hence, the method will be of use for the rational design of ligands in the context of chemical biology and the development of therapeutic agents.

  1. ROLE OF SURFACE FUNCTIONAL GROUPS IN THE CAPTURE OF ELEMENTAL MERCURY AND MERCURIC CHLORIDE BY ACTIVATED CARBONS

    EPA Science Inventory

    The paper discusses using a laboratory-scale, fixed bed apparatus to study the role of surface functional groups (SFGs) in the capture of mercuric chloride (HgC12) and elemental mercury (Hgo) in nitrogen (N2) prior to flue gas atmosphere studies. The study focused on two activat...

  2. Assessing the temporal stability of surface functional groups introduced by plasma treatments on the outer shells of carbon nanotubes

    PubMed Central

    Merenda, Andrea; Ligneris, Elise des; Sears, Kallista; Chaffraix, Thomas; Magniez, Kevin; Cornu, David; Schütz, Jürg A.; Dumée, Ludovic F.

    2016-01-01

    Plasma treatments are emerging as superior efficiency treatment for high surface to volume ratio materials to tune functional group densities and alter crystallinity due to their ability to interact with matter at the nanoscale. The purpose of this study is to assess for the first time the long term stability of surface functional groups introduced across the surface of carbon nanotube materials for a series of oxidative, reductive and neutral plasma treatment conditions. Both plasma duration dose matrix based exposures and time decay experiments, whereby the surface energy of the materials was evaluated periodically over a one-month period, were carried out. Although only few morphological changes across the graphitic planes of the carbon nanotubes were found under the uniform plasma treatment conditions, the time dependence of pertinent work functions, supported by Raman analysis, suggested that the density of polar groups decreased non-linearly over time prior to reaching saturation from 7 days post treatment. This work provides critical considerations on the understanding of the stability of functional groups introduced across high specific surface area nano-materials used for the design of nano-composites, adsorptive or separation systems, or sensing materials and where interfacial interactions are key to the final materials performance. PMID:27507621

  3. Assessing the temporal stability of surface functional groups introduced by plasma treatments on the outer shells of carbon nanotubes.

    PubMed

    Merenda, Andrea; Ligneris, Elise des; Sears, Kallista; Chaffraix, Thomas; Magniez, Kevin; Cornu, David; Schütz, Jürg A; Dumée, Ludovic F

    2016-01-01

    Plasma treatments are emerging as superior efficiency treatment for high surface to volume ratio materials to tune functional group densities and alter crystallinity due to their ability to interact with matter at the nanoscale. The purpose of this study is to assess for the first time the long term stability of surface functional groups introduced across the surface of carbon nanotube materials for a series of oxidative, reductive and neutral plasma treatment conditions. Both plasma duration dose matrix based exposures and time decay experiments, whereby the surface energy of the materials was evaluated periodically over a one-month period, were carried out. Although only few morphological changes across the graphitic planes of the carbon nanotubes were found under the uniform plasma treatment conditions, the time dependence of pertinent work functions, supported by Raman analysis, suggested that the density of polar groups decreased non-linearly over time prior to reaching saturation from 7 days post treatment. This work provides critical considerations on the understanding of the stability of functional groups introduced across high specific surface area nano-materials used for the design of nano-composites, adsorptive or separation systems, or sensing materials and where interfacial interactions are key to the final materials performance. PMID:27507621

  4. Priority effects of time of arrival of plant functional groups override sowing interval or density effects: a grassland experiment.

    PubMed

    von Gillhaussen, Philipp; Rascher, Uwe; Jablonowski, Nicolai D; Plückers, Christine; Beierkuhnlein, Carl; Temperton, Vicky M

    2014-01-01

    Priority effects occur when species that arrive first in a habitat significantly affect the establishment, growth, or reproduction of species arriving later and thus affect functioning of communities. However, we know little about how the timing of arrival of functionally different species may alter structure and function during assembly. Even less is known about how plant density might interact with initial assembly. In a greenhouse experiment legumes, grasses or forbs were sown a number of weeks before the other two plant functional types were sown (PFT) in combination with a sowing density treatment. Legumes, grasses or non-legume forbs were sown first at three different density levels followed by sowing of the remaining PFTs after three or six-weeks. We found that the order of arrival of different plant functional types had a much stronger influence on aboveground productivity than sowing density or interval between the sowing events. The sowing of legumes before the other PFTs produced the highest aboveground biomass. The larger sowing interval led to higher asymmetric competition, with highest dominance of the PFT sown first. It seems that legumes were better able to get a head-start and be productive before the later groups arrived, but that their traits allowed for better subsequent establishment of non-legume PFTs. Our study indicates that the manipulation of the order of arrival can create priority effects which favour functional groups of plants differently and thus induce different assembly routes and affect community composition and functioning.

  5. Priority effects of time of arrival of plant functional groups override sowing interval or density effects: a grassland experiment.

    PubMed

    von Gillhaussen, Philipp; Rascher, Uwe; Jablonowski, Nicolai D; Plückers, Christine; Beierkuhnlein, Carl; Temperton, Vicky M

    2014-01-01

    Priority effects occur when species that arrive first in a habitat significantly affect the establishment, growth, or reproduction of species arriving later and thus affect functioning of communities. However, we know little about how the timing of arrival of functionally different species may alter structure and function during assembly. Even less is known about how plant density might interact with initial assembly. In a greenhouse experiment legumes, grasses or forbs were sown a number of weeks before the other two plant functional types were sown (PFT) in combination with a sowing density treatment. Legumes, grasses or non-legume forbs were sown first at three different density levels followed by sowing of the remaining PFTs after three or six-weeks. We found that the order of arrival of different plant functional types had a much stronger influence on aboveground productivity than sowing density or interval between the sowing events. The sowing of legumes before the other PFTs produced the highest aboveground biomass. The larger sowing interval led to higher asymmetric competition, with highest dominance of the PFT sown first. It seems that legumes were better able to get a head-start and be productive before the later groups arrived, but that their traits allowed for better subsequent establishment of non-legume PFTs. Our study indicates that the manipulation of the order of arrival can create priority effects which favour functional groups of plants differently and thus induce different assembly routes and affect community composition and functioning. PMID:24497995

  6. Inhibition of oxidative stress by low-molecular-weight polysaccharides with various functional groups in skin fibroblasts.

    PubMed

    Chen, Szu-Kai; Hsu, Chu-Hsi; Tsai, Min-Lang; Chen, Rong-Huei; Drummen, Gregor P C

    2013-09-25

    The aim of this study was to evaluate the in cellulo inhibition of hydrogen-peroxide-induced oxidative stress in skin fibroblasts using different low-molecular-weight polysaccharides (LMPS) prepared from agar (LMAG), chitosan (LMCH) and starch (LMST), which contain various different functional groups (i.e., sulfate, amine, and hydroxyl groups). The following parameters were evaluated: cell viability, intracellular oxidant production, lipid peroxidation, and DNA damage. Trolox was used as a positive control in order to allow comparison of the antioxidant efficacies of the various LMPS. The experimentally determined attenuation of oxidative stress by LMPS in skin fibroblasts was: LMCH > LMAG > LMST. The different protection levels of these LMPS may be due to the physic-chemical properties of the LMPS' functional groups, including electron transfer ability, metal ion chelating capacities, radical stabilizing capacity, and the hydrophobicity of the constituent sugars. The results suggest that LMCH might constitute a novel and potential dermal therapeutic and sun-protective agent.

  7. Hierarchical Spectral Consensus Clustering for Group Analysis of Functional Brain Networks.

    PubMed

    Ozdemir, Alp; Bolaños, Marcos; Bernat, Edward; Aviyente, Selin

    2015-09-01

    A central question in cognitive neuroscience is how cognitive functions depend on the integration of specialized widely distributed brain regions. In recent years, graph theoretical methods have been used to characterize the structure of the brain functional connectivity. In order to understand the organization of functional connectivity networks, it is important to determine the community structure underlying these complex networks. Moreover, the study of brain functional networks is confounded by the fact that most neurophysiological studies consists of data collected from multiple subjects; thus, it is important to identify communities representative of all subjects. Typically, this problem is addressed by averaging the data across subjects which omits the variability across subjects or using voting methods, which requires a priori knowledge of cluster labels. In this paper, we propose a hierarchical consensus spectral clustering approach to address these problems. Furthermore, new information-theoretic criteria are introduced for selecting the optimal community structure. The proposed framework is applied to electroencephalogram data collected during a study of error-related negativity to better understand the community structure of functional networks involved in the cognitive control.

  8. Verbal and Nonverbal Student Interaction in the College Classroom as a Function of Group Cohesion.

    ERIC Educational Resources Information Center

    von Raffler-Engel, Walburga; And Others

    The correlation of verbal, paralinguistic, and kinesic features in the context of student-student and student-teacher interaction is studied in a semester linguistics course at Vanderbilt University. The purpose of the research is to delineate some of the major problems of group interaction in the college classroom and to show how the various…

  9. A facile synthetic route to poly(p-phenylene terephthalamide) with dual functional groups.

    PubMed

    Du, Shuming; Wang, Wenbin; Yan, Yan; Zhang, Jie; Tian, Ming; Zhang, Liqun; Wan, Xinhua

    2014-09-01

    Claisen rearrangement reaction was employed for the first time to obtain a novel PPTA bearing reactive allyl and hydroxyl groups which may act as a sizing agent of Kevlar fibers to improve the interface structure and interfacial adhesion of rubber or epoxy based composites.

  10. Age Group Differences in Depressive Symptoms among Older Adults with Functional Impairments

    ERIC Educational Resources Information Center

    Choi, Namkee G.; Kim, Johnny S.

    2007-01-01

    This study used data from the 2000 interview wave of the Health and Retirement Study to examine age group differences in the likelihood of self-reported depressive symptomatology among a nationally representative sample of 3,035 adults age 55 years or older who had at least one activities of daily living (ADL) or instrumental activities of daily…

  11. Changes in the Ethnocentrism of a Select Group of College Students as a Function of Bibliotherapy.

    ERIC Educational Resources Information Center

    Alsbrook, Eleanor Young

    The purpose of this study is to investigate bibliotherapy relative to changes in the ethnocentrism of four groups of adult, white college students at the University of Louisville. The study seeks to establish the extent of prejudice exhibited by the selected subjects, and with the use of bibliotherapeutic techniques as an input to the selected…

  12. The Referential Function of Internal Communication Groups in Complex Organizations: An Empirical Analysis.

    ERIC Educational Resources Information Center

    Taylor, James A.; Farace, Richard V.

    This paper argues that people who interact regularly and repetitively among themselves create a conjoint information space wherein common values, attitudes, and beliefs arise through the process of information transmission among the members in the space. Three major hypotheses concerning informal communication groups in organizations were tested…

  13. In vitro behavior of neural stem cells in response to different chemical functional groups.

    PubMed

    Ren, Yong-Juan; Zhang, Han; Huang, Hua; Wang, Xiu-Mei; Zhou, Zi-You; Cui, Fu-Zhai; An, Yi-Hua

    2009-02-01

    Neural stem cells (NSCs) cultured on glass surfaces modified by different chemical groups, including hydroxyl (-OH), sulfonic (-SO3H), amino (-NH2), carboxyl (-COOH), mercapto (-SH) and methyl (-CH3) groups, are shown here to commit to phonotypes with extreme sensitivity to surface chemical groups. The adhering NSCs at the level of single cells exhibited morphological changes in response to different chemical groups. NSCs on -SO(3)H surfaces had the largest contact area and the most flattened morphology, while those on -CH(3) surfaces exhibited the smallest contact area and the most rounded morphology. After 5 days of culture, the migration of NSCs from their original aggregates onto these test surfaces followed the trend: -NH2>-COOH=-SH>-SO3H>-CH3>-OH. The expression of specific markers, including nestin, beta-Tubulin-III, glial fibrillary acidic protein and O4, were used to examine NSCs lineage specification. The -SO3H surfaces favored NSCs differentiation into oligodendrocytes, while NSCs in contact with -COOH, -NH2, -SH and -CH3 had the ability to differentiate into neurons, astrocytes and oligodendrocytes. Compared to -COOH surfaces, -NH2 seemed to promote neuronal differentiation. These chemically modified surfaces exhibited regulation of NSCs on adhesion, migration and differentiation potential, providing chemical means for the design of biomaterials to direct NSCs lineage specification for neural tissue engineering. PMID:19026444

  14. Strontium adsorption properties of an aluminum-pillared montmorillonite carrying carboxylate functional groups.

    PubMed

    Papachristodoulou, C A; Assimakopoulos, P A; Gangas, N-H J

    2002-01-01

    Strontium adsorption was studied in an aluminum-pillared montmorillonite (PILC) carrying organic acid groups. The in situ dissociation of these groups increases the number of negative sites in the modified PILC, promoting thus the uptake of cations from an exchange solution. To investigate the role of solution pH and acid strength in cation uptake phenomena, base titrations were performed for PILCs carrying either oxalate or acetate groups. Comparison with the pristine PILC showed that extra Sr(2+) uptake initiated at pH 6 and 8 in the presence of oxalate and acetate, respectively. The overall increase in Sr(2+) uptake was higher in the presence of oxalate and amounted to about 136% as compared with the pristine PILC, at pH slightly above 8. The effect of the acid's strength was further probed through strontium adsorption isotherms, taken at a constant pH for PILC samples carrying acetate, oxalate, malonate, or citrate groups. The results demonstrate that cation uptake can be optimized by tuning the pH conditions to the acid's strength or vice versa. PMID:16290332

  15. Preliminary Study of Resilience-Based Group Therapy for Improving the Functioning of Anxious Children

    ERIC Educational Resources Information Center

    Watson, Candice C.; Rich, Brendan A.; Sanchez, Lisa; O'Brien, Kelly; Alvord, Mary K.

    2014-01-01

    Background: There is a lack of research examining the feasibility of group psychotherapy interventions for anxious children in private clinical service settings. Furthermore, no research to date has examined the effectiveness of resilience-based interventions for helping children with anxiety disorders. Objective: The present study aims to examine…

  16. Group Emotions: The Social and Cognitive Functions of Emotions in Argumentation

    ERIC Educational Resources Information Center

    Polo, Claire; Lund, Kristine; Plantin, Christian; Niccolai, Gerald P.

    2016-01-01

    The learning sciences of today recognize the tri-dimensional nature of learning as involving cognitive, social and emotional phenomena. However, many computer-supported argumentation systems still fail in addressing the socio-emotional aspects of group reasoning, perhaps due to a lack of an integrated theoretical vision of how these three…

  17. The Effect of Methyl, Hydroxyl, and Ketone Functional Groups on the Heterogeneous Oxidation of Succinic Acid Aerosol by OH Radicals

    NASA Astrophysics Data System (ADS)

    Chan, M.; Zhang, H.; Wilson, K. R.

    2013-12-01

    The heterogeneous oxidation of atmospheric organic aerosols can influence their effects on climate, human health, and visibility. During oxidation, functionalization occurs when an oxygenated functional group is added to a molecule, leaving the carbon skeleton intact. Fragmentation involves carbon-carbon bond cleavage and produces two products with smaller carbon numbers than the parent compound. To gain better insights into how the molecular structure of more oxygenated organic compounds affects heterogeneous reactivity, succinic acid aerosols are photo-oxidized in an aerosol flow tube reactor, and the reaction products are analyzed using Direct Analysis in Real Time Mass Spectrometry for online chemical analysis. The effect of various functional groups (CH3, OH, C=O) along the carbon backbone on the heterogeneous reaction mechanisms are also investigated using model compounds. For this series of compounds, the formation of more oxygenated products through functionalization can be explained by well-known condensation-phase reactions such as Russell and Bennett and Summers. The number of fragmentation products is found to increase with the presence of OH and CH3 groups. This can be attributed to the increased number of tertiary carbons, enhancing the fragmentation after multiple oxidation steps. Smaller dicaids (oxalic acid and malonic acid) can be formed through the fragmentation processes in the heterogeneous oxidation of succinic acid. The effect of molecular structure on reaction kinetics, volatilization, and the relative importance of functionalization and fragmentation pathways will be discussed.

  18. Effects of species and functional group richness on production in two fertility environments: an experiment with communities of perennial plants

    NASA Astrophysics Data System (ADS)

    Lanta, Vojtěch; Lepš, Jan

    2007-07-01

    The effects of species and functional group richness of sown species and fertilization on productivity and invasion of colonizers (i.e. unsown species) were studied in a three year field experiment. Both species and functional group numbers positively affected the average yield of sown species, but the effect changed among the three years. The biomass of colonizers generally decreased with the biomass of sown species, and so was negatively affected by the diversity characteristics of sown species. All three characteristics of biodiversity (selection, complementarity and overyielding effects) varied greatly during the study period, depending on both species and functional group richness and nutrient amendment. Functional differences among species led to the detection of high values of complementarity (resource use complementarity and/or facilitation), however this effect was not sufficient to cause transgressive overyielding. The compositional difference between fertilized and non-fertilized control plots increased with both time and species richness, whereas the relative difference in productivity decreased. This shows that the changes in species composition toward the one best-suited to the given environment, can lead to optimal resource use among plant species, and, as a consequence, diminish variation in community functioning in a changing environment.

  19. Unbiased group-wise image registration: applications in brain fiber tract atlas construction and functional connectivity analysis.

    PubMed

    Geng, Xiujuan; Gu, Hong; Shin, Wanyong; Ross, Thomas J; Yang, Yihong

    2011-10-01

    We propose an unbiased implicit-reference group-wise (IRG) image registration method and demonstrate its applications in the construction of a brain white matter fiber tract atlas and the analysis of resting-state functional MRI (fMRI) connectivity. Most image registration techniques pair-wise align images to a selected reference image and group analyses are performed in the reference space, which may produce bias. The proposed method jointly estimates transformations, with an elastic deformation model, registering all images to an implicit reference corresponding to the group average. The unbiased registration is applied to build a fiber tract atlas by registering a group of diffusion tensor images. Compared to reference-based registration, the IRG registration improves the fiber track overlap within the group. After applying the method in the fMRI connectivity analysis, results suggest a general improvement in functional connectivity maps at a group level in terms of larger cluster size and higher average t-scores.

  20. Functional comparison of homologous members of three groups of Kunitz-type enzyme inhibitors from potato tubers (Solanum tuberosum L.).

    PubMed

    Heibges, A; Salamini, F; Gebhardt, C

    2003-07-01

    For functional studies, nine cDNAs encoding Kunitz-type enzyme inhibitors from potato tubers were expressed as GST (glutathione S transferase)-tagged fusion proteins in the fission yeast Schizosaccharomyces pombe. The inhibitors represented the three major homology groups A, B and C found in tubers. Members of the same homology group were at least 90% identical in sequence. The purified GST fusion proteins were tested for their ability to inhibit the proteases trypsin, alpha-chymotrypsin, subtilisin, papain and aspergillopepsin I, and for inhibition of the growth of fungi. Fusion proteins belonging to the same and different homology groups were found to exhibit distinct protease inhibition profiles. Removal of the GST tag by cleavage with enterokinase did not change the inhibition profile but increased the inhibitory activity. Group A and B inhibitors affected the proteases to different extents, whereas group C inhibitors showed only weak or no protease inhibition. One fusion protein completely inhibited aspergillopepsin I. One fusion protein each of groups A and B strongly inhibited mycelial growth of the fungus Fusarium moniliforme. The results suggest functional polymorphism among closely related members of the Kunitz-type inhibitor family.

  1. Role of membrane-associated thiol groups in the functional regulation of gastric microsomal (H+ + K+)-transporting ATPase system.

    PubMed Central

    Nandi, J; Meng-Ai, Z; Ray, T K

    1983-01-01

    The distribution of free thiol groups associated with the membrane proteins of the purified pig gastric microsomal vesicles was quantified, and the relation of thiol groups to the function of the gastric (H+ + K+)-transporting ATPase system was investigated. Two different thiol-specific agents, carboxypyridine disulphide (CPDS) and N-(1-naphthyl)maleimide (NNM) were used for the study. The structure-function relationship of the membrane thiol groups was studied after modification by the probes under various conditions, relating the inhibition of the (H+ + K+)-transporting ATPase to the ATP-dependent H+ accumulation by the gastric microsomal vesicles. On the basis of the extent of stimulation of the microsomal (H+ + K+)-transporting ATPase in the presence and absence of valinomycin (val) about 85% of the vesicles were found to be intact. CPDS at 1 mM completely inhibits the valinomycin-stimulated ATPase and the associated p-nitrophenyl phosphatase with a concomitant inhibition of vesicular H+ uptake. Both the enzyme and dye-uptake activities were fully protected against CPDS inhibition when the treatment with CPDS was carried out in the presence of ATP. ATP also offered protection (about 65%) against NNM inhibition of the (H+ + K+)-transporting ATPase system and vesicular H+ uptake. Under similar conditions ATP also protected about 10 and 6 nmol of thiol groups/mg of protein respectively from CPDS and NNM reaction. Our data suggest that the thiol groups on the outer surface of the vesicles are primarily involved in gastric (H+ + K+)-transporting ATPase function. Furthermore, at least about 15% of the total microsomal thiol groups appear to be associated with the ATPase system. The data have been discussed in terms of the structure-function relationship of gastric microsomes. PMID:6311168

  2. Thioetherification of chloroheteroarenes: a binuclear catalyst promotes wide scope and high functional-group tolerance.

    PubMed

    Platon, Mélanie; Wijaya, Novi; Rampazzi, Vincent; Cui, Luchao; Rousselin, Yoann; Saeys, Mark; Hierso, Jean-Cyrille

    2014-09-22

    A constrained binuclear palladium catalyst system affords selective thioetherification of a wide range of functionalized arenethiols with chloroheteroaromatic partners with the highest turnover numbers (TONs) reported to date and tolerates a large variety of reactive functions. The scope of this system includes the coupling of thiophenols with six- and five-membered 2-chloroheteroarenes (i.e., functionalized pyridine, pyrazine, quinoline, pyrimidine, furane, and thiazole) and 3-bromoheteroarenes (i.e., pyridine and furane). Electron-rich congested thiophenols and fluorinated thiophenols are also suitable partners. The coupling of unprotected amino-2-chloropyridines with thiophenol and the successful employment of synthetically valuable chlorothiophenols are described with the same catalyst system. DFT studies attribute the high performance of this binuclear palladium catalyst to the decreased stability of thiolate-containing resting states. Palladium loading was as low as 0.2 mol %, which is important for industrial application and is a step forward in solving catalyst activation/deactivation problems.

  3. Thioetherification of chloroheteroarenes: a binuclear catalyst promotes wide scope and high functional-group tolerance.

    PubMed

    Platon, Mélanie; Wijaya, Novi; Rampazzi, Vincent; Cui, Luchao; Rousselin, Yoann; Saeys, Mark; Hierso, Jean-Cyrille

    2014-09-22

    A constrained binuclear palladium catalyst system affords selective thioetherification of a wide range of functionalized arenethiols with chloroheteroaromatic partners with the highest turnover numbers (TONs) reported to date and tolerates a large variety of reactive functions. The scope of this system includes the coupling of thiophenols with six- and five-membered 2-chloroheteroarenes (i.e., functionalized pyridine, pyrazine, quinoline, pyrimidine, furane, and thiazole) and 3-bromoheteroarenes (i.e., pyridine and furane). Electron-rich congested thiophenols and fluorinated thiophenols are also suitable partners. The coupling of unprotected amino-2-chloropyridines with thiophenol and the successful employment of synthetically valuable chlorothiophenols are described with the same catalyst system. DFT studies attribute the high performance of this binuclear palladium catalyst to the decreased stability of thiolate-containing resting states. Palladium loading was as low as 0.2 mol %, which is important for industrial application and is a step forward in solving catalyst activation/deactivation problems. PMID:25112971

  4. Day Care Interactions and Teacher Perceptions as a Function of Teacher and Child Ethnic Group.

    ERIC Educational Resources Information Center

    Arnold, David Harvey; Griffith, Jessica R.; Ortiz, Camilo; Stowe, Rebecca M.

    1998-01-01

    Examined low socioeconomic-status (SES) preschool classrooms for teacher perceptions of children and teacher/child interactions as a function of ethnicity. Hispanic teachers described Hispanic boys as having high levels of difficulty; they engaged in high levels of interaction with them. Perceptions of girls were more positive and less influenced…

  5. 14 CFR Section 10 - Functional Classification-Operating Expenses of Group I Air Carriers

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... productive use of property and equipment. (b) This function shall include the cost of direct labor, materials... direct labor, materials and supplies, as well as outside repairs, used in the maintenance and repair of..., inspectors and foremen are engaged in direct labor in connection with equipment maintenance, a...

  6. [Investigation of functional groups of Cryptococcus albidus alpha-L-rhamnosidase].

    PubMed

    Gudzenko, O V; Varbanets', L D

    2012-01-01

    The effect of cations, anions and specific chemical reagents: 1-[3-(dimethylamino)propyl]-3-ethylcarbodimide methiodide, EDTA, o-phenantroline, dithiotreitol, L-cysteine, beta-mercaptoethanol, p-chlormercurybenzoate (p-ChMB), N-ethylmaleimide on the alpha-L-rhamnosidase activity of Cryptococcus albidus has been investigated. The essential role of Ag+ which inhibits the alpha-L-rhamnosidase activity by 72.5% was shown. Rhamnose at 1-5 mM protect the enzyme from the negative effect of Ag(+). It was expected that carboxyl group of C-terminal aminoacid and imidazole group of histidine would participate in the catalytic action of alpha-L-rhamnosidase on the basis of inhibition and kinetic analysis. PMID:23088096

  7. Quantitative distribution and functional groups of intertidal macrofaunal assemblages in Fildes Peninsula, King George Island, South Shetland Islands, Southern Ocean.

    PubMed

    Liu, Xiaoshou; Wang, Lu; Li, Shuai; Huo, Yuanzi; He, Peimin; Zhang, Zhinan

    2015-10-15

    To evaluate spatial distribution pattern of intertidal macrofauna, quantitative investigation was performed in January to February, 2013 around Fildes Peninsula, King George Island, South Shetland Islands. A total of 34 species were identified, which were dominated by Mollusca, Annelida and Arthropoda. CLUSTER analysis showed that macrofaunal assemblages at sand-bottom sites belonged to one group, which was dominated by Lumbricillus sp. and Kidderia subquadrata. Macrofaunal assemblages at gravel-bottom sites were divided into three groups while Nacella concinna was the dominant species at most sites. The highest values of biomass and Shannon-Wiener diversity index were found in gravel sediment and the highest value of abundance was in sand sediment of eastern coast. In terms of functional group, detritivorous and planktophagous groups had the highest values of abundance and biomass, respectively. Correlation analysis showed that macrofaunal abundance and biomass had significant positive correlations with contents of sediment chlorophyll a, phaeophorbide and organic matter.

  8. Holographic phase space: c-functions and black holes as renormalization group flows

    NASA Astrophysics Data System (ADS)

    Paulos, Miguel F.

    2011-05-01

    We construct a mathcal{N} -function for Lovelock theories of gravity, which yields a holographic c-function in domain-wall backgrounds, and seemingly generalizes the concept for black hole geometries. A flow equation equates the monotonicity properties of mathcal{N} with the gravitational field, which has opposite signs in the domain-wall and black hole backgrounds, due to the presence of negative/positive energy in the former/latter, and accordingly mathcal{N} monotonically decreases/increases from the UV to the IR. On AdS spaces the mathcal{N} -function is related to the Euler anomaly, and at a black hole horizon it is generically proportional to the entropy. For planar black holes, mathcal{N} diverges at the horizon, which we interpret as an order N 2 increase in the number of effective degrees of freedom. We show how mathcal{N} can be written as the ratio of the Wald entropy to an effective phase space volume, and using the flow equation relate this to Verlinde's notion of gravity as an entropic force. From the effective phase space we can obtain an expression for the dual field theory momentum cut-off, matching a previous proposal in the literature by Polchinski and Heemskerk. Finally, we propose that the area in Planck units counts states, not degrees of freedom, and identify it also as a phase space volume. Written in terms of the proper radial distance β, it takes the suggestive form of a canonical partition function at inverse temperature β, leading to a "mean energy" which is simply the extrinsic curvature of the surface. Using this we relate this definition of holographic phase space with the effective phase space appearing in the mathcal{N} -function.

  9. [Peculiarities of structure-function organization of microbial groups of soil contaminated by cement dust].

    PubMed

    Stefurak, V P

    2001-01-01

    Long-term contamination of the forest soil by the cement dust leads to disturbances of stability of natural microbial groups, changes their quantitative and qualitative composition, results in substitution of some microbial associations by other ones. The intensive contamination of the soil by the effluents of cement integrated works, inhibits the intensity of nitrogen fixation processes and decay of the forest litter, development of micromycetes, results in the decrease of the length of mycelium and its biomass. PMID:11692672

  10. Hydrogel with chains functionalized with carboxyl groups as universal 3D platform in DNA biosensors.

    PubMed

    Kowalczyk, Agata; Fau, Michal; Karbarz, Marcin; Donten, Mikolaj; Stojek, Zbigniew; Nowicka, Anna M

    2014-04-15

    Application of hydrogel based on N-isopropylacrylamide with carboxyl groups grafted to the chains enabled the immobilization of DNA at an extent exceeding that for flat surfaces by at least one order of magnitude. The probe DNA strands in the 3D platform were fully available for the hybridization process. The examination of the gels containing different amounts of grafted carboxyl groups (1-10%) was done using quartz crystal microbalance, electrochemical impedance spectroscopy, chronoamperometry and ionic coupled plasma with laser ablation. The optimal carboxyl group content was determined to be 5%. A very good agreement of the data obtained with independent techniques on content of DNA in the gel was obtained. In comparison to the other methods of immobilization of DNA the new platform enabled complete removal of DNA after the measurements and analysis and, therefore, could be used many times. After a 10-fold exchange of the DNA-sensing layer the efficiency of hybridization and analytical signal did not change by more than 5%. The sensor response increased linearly with logarithm of concentration of target DNA in the range 1×10(-13)-1×10(-6) M. The obtained detection limit was circa 8×10(-13) M of target DNA in the sample which is a substantial improvement over the planar sensing layers. PMID:24287408

  11. First-Principles Density Functional Theory Modeling Study on the Redox Chemistry of Graphene Oxides Affected by Placement Geometry of Oxygen Functional Groups

    NASA Astrophysics Data System (ADS)

    Kim, Sunghee; Kim, Ki Chul; Lee, Seung Woo; Jang, Seung Soon

    2015-03-01

    To date, lithium-ion batteries have been extensively gained attention due to their promising potential in the industry. Despite their promising properties, improving their poor power density is still needed for practical applications. In addition, sustaining the high redox potential in the lithium-ion batteries is prerequisite for exhibiting the high energy and power densities. Recently, layered carbon materials including graphenes and carbon nanotubes have been paid special attention as promising electrode candidates with high power densities due to their exceptionally high surface area and active oxygen functional groups on their surfaces. However, the lack of reliable information on the redox chemistry of the candidates is the obstacle to be uncovered for practical applications. In this study, we investigated the redox chemistry of graphene oxides cluster models with well-controlled hydroxyl functional groups at the edge. First-principles density functional theory approach was employed to understand the geometric effect of the incorporated hydroxyl functional groups on the redox chemistry. Our study will provide an insight on the strategy for improving the redox potentials of graphene-based electrode candidates.

  12. S-functions, spectral functions of hyperbolic geometry, and vertex operators with applications to structure for Weyl and orthogonal group invariants

    NASA Astrophysics Data System (ADS)

    Bytsenko, A. A.; Chaichian, M.

    2016-06-01

    In this paper we analyze the quantum homological invariants (the Poincaré polynomials of the slN link homology). In the case when the dimensions of homologies of appropriate topological spaces are precisely known, the procedure of the calculation of the Kovanov-Rozansky type homology, based on the Euler-Poincaré formula can be appreciably simplified. We express the formal character of the irreducible tensor representation of the classical groups in terms of the symmetric and spectral functions of hyperbolic geometry. On the basis of Labastida-Mariño-Ooguri-Vafa conjecture, we derive a representation of the Chern-Simons partition function in the form of an infinite product in terms of the Ruelle spectral functions (the cases of a knot, unknot, and links have been considered). We also derive an infinite-product formula for the orthogonal Chern-Simons partition functions and analyze the singularities and the symmetry properties of the infinite-product structures.

  13. Adsorption of pesticidal compounds bearing a single carboxyl functional group and biogenic amines by humic fraction-immobilized silica gel.

    PubMed

    Chen, Cheng-Sheng; Chen, Shushi

    2013-04-17

    Fractions collected from humic acids under acidic and basic conditions were immobilized on silica gel and used as adsorbents for a variety of agricultural pesticide compounds bearing a single carboxyl functional group and biogenic amines in acetonitrile. Among these compounds examined under the same conditions, the percentage of adsorption varies considerably from 0 to almost 100%. The percentage is found to be highly related to the structure of the analyte and the type of functional group attached to it. The adsorption, better performed on adsorbent immobilized with the fraction collected under acidic conditions, is believed to result from the reversible interaction between the functional moieties of the analyte and humic acids (e.g., amino or carboxyl group of analyte vs carboxyl group of humic acids, etc.) as no adsorption is observed under the same conditions for analytes that are derivatives of alcohol, amide, and ester. Given the nature of the analyte, the time needed to reach the maximum percent of adsorption decreases as the amount of adsorbent is increased. Also, the longer the time that has elapsed, the higher the percentage of analyte adsorbed, thus indicating that the adsorption process is surface-oriented. Factors such as the acidic or basic origin of the additive in the liquid phase of the matrix also affect the percentage of analyte adsorbed. PMID:23521499

  14. Functional groups and elemental analyses of cuticular morphotypes of Cordaites principalis (Germar) Geinitz, Carboniferous Maritimes Basin, Canada

    USGS Publications Warehouse

    Zodrow, E.L.; Mastalerz, Maria; Orem, W.H.; Simunek, Z.; Bashforth, A.R.

    2000-01-01

    Well-preserved cuticles were isolated from Cordaites principalis (Germar) Geinitz leaf compressions, i.e., foliage from extinct gymnosperm trees Coniferophyta: Order Cordaitales. The specimens were collected from the Sydney. Stellarton and Bay St. George subbasins of the once extensive Carboniferous Maritimes Basin of Atlantic Canada. Fourier transformation of infrared spectra (FTIR) and elemental analyses indicate that the ca. 300-306-million-year-old fossil cuticles share many of the functional groups observed in modern cuticles. The similarities of the functional groups in each of the three cuticular morphotypes studied support the inclusion into a single cordaite-leaf taxon, i.e., C. principalis (Germar), confirming previous morphological investigations. Vitrinite reflectance measurements on coal seams in close proximity to the fossil-bearing sediments reveal that the Bay St. George sample site has the lowest thermal maturity, whereas the sites in Sydney and Stellarton are more mature. IR absorption and elemental analyses of the cordaite compressions corroborate this trend, which suggests that the coalified mesophyll in the leaves follows a maturation path similar to that of vitrinite. Comparison of functional groups of the cordaite cuticles with those from certain pteridosperms previously studied from the Sydney Subbasin shows that in the cordaite cuticles highly conjugated C-O (1632 cm-1) bands dominate over carbonyl stretch that characterizes the pteridosperm cuticles. The differences demonstrate the potential of chemotaxonomy as a valuable tool to assist distinguishing between Carboniferous plant-fossil groups. Published by Elsevier Science B.V.

  15. Influence of functional groups on the C α-C β chain of L-phenylalanine and its derivatives

    NASA Astrophysics Data System (ADS)

    Ganesan, Aravindhan; Brunger, Michael; Wang, Feng

    2010-07-01

    L-phenylalanine ( L-phe) consists of three different functional groups, i.e., phenyl, carboxyl (-COOH) and amino (-NH 2), joining through the C α-C β bridge. Substitution of these groups produces 2-phenethylamine (PEA) and 3-phenylpropionic acid (PPA). Electronic structures of L-phe, PEA and PPA together with smaller "fragments" L-alanine and benzene were determined using density functional theory (DFT), from which core and valence shell ionization spectra were simulated. Comparison of the spectra reveals that core shell ionization energies clearly indicate that the carbon bridge is significantly affected by their functional group substitutions particularly at the C α site. In the valence space, quite unexpectedly, the frontier orbitals are concentrated on the benzene group although some energy splitting is observed. The orbitals which significantly affect the C α-C β carbon backbone are from the inner valence shell in the ionization energy region of 20-26 eV of the molecules.

  16. End Groups of Functionalized Siloxane Oligomers Direct Block-Copolymeric or Liquid-Crystalline Self-Assembly Behavior

    PubMed Central

    2016-01-01

    Monodisperse oligodimethylsiloxanes end-functionalized with the hydrogen-bonding ureidopyrimidinone (UPy) motif undergo phase separation between their aromatic end groups and dimethylsiloxane midblocks to form ordered nanostructures with domain spacings of <5 nm. The self-assembly behavior of these well-defined oligomers rese