CHARACTERIZATION OF BULK SOIL HUMIN AND ITS ALKALINE-SOLUBLE AND ALKALINE-INSOLUBLE FRACTIONS

Humic substances are the major components of soil organic matter. Among the three humic substance components (humic acid, fulvic acid, and humin), humin is the most insoluble in aqueous solution at any pH value and, in turn, the least understood. Humin has poor solubility mainly because it is tightly bonded to inorganic soil colloids. By breaking the linkage between humin and inorganic soil colloids using inorganic or organic solvents, bulk humin can be partially soluble in alkali, enabling a better understanding of the structure and properties of humin. However, the structural relationship between bulk humin and its alkaline-soluble (AS) and alkaline-insoluble (AIS) fractions is still unknown. In this study, we isolated bulk humin from two soils of Northeast China by exhaustive extraction (25 to 28 times) with 0.1 mol L-1 NaOH + 0.1 mol L-1 Na4P2O7, followed by the traditional treatment with 10 % HF-HCl. The isolated bulk humin was then fractionated into AS-humin and AIS-humin by exhaustive extraction (12 to 15 times) with 0.1 mol L-1 NaOH. Elemental analysis and solid-state 13C cross-polarization magic angle spinning nuclear magnetic resonance (13C CPMAS NMR) spectroscopy were used to characterize and compare the chemical structures of bulk humin and its corresponding fractions. The results showed that, regardless of soil types, bulk humin was the most aliphatic and most hydrophobic, AS-humin was the least aliphatic, and AIS-humin was the least alkylated among the three humic components. The results showed that bulk humin and its corresponding AS-humin and AIS-humin fractions are structurally differed from one another, implying that the functions of these humic components in the soil environment differed.

Analytic behavior of the QED polarizability function at finite temperature

We revisit the analytical properties of the static quasi-photon polarizability function for an electron gas at finite temperature, in connection with the existence of Friedel oscillations in the potential created by an impurity. In contrast with the zero temperature case, where the polarizability is an analytical function, except for the two branch cuts which are responsible for Friedel oscillations, at finite temperature the corresponding function is non analytical, in spite of becoming continuous everywhere on the complex plane. This effect produces, as a result, the survival of the oscillatory behavior of the potential. We calculate the potential at large distances, and relate the calculation to the non-analytical properties of the polarizability.

Faire la ville juste : une analyse "in itinere" de la maîtrise publique d'ouvrage du projet urbain Carré de Soie (métropole lyonnaise)

Dans certaines portions des agglomérations (poches de pauvreté de centre-ville, couronnes suburbaines dégradées, espaces périurbains sans aménité), un cumul entre des inégalités sociales (pauvreté, chômage, etc.) et environnementales (exposition au bruit, aux risques industriels, etc.) peut être observé. La persistance de ces inégalités croisées dans le temps indique une tendance de fond : la capacité d'accéder à un cadre de vie de qualité n'est pas équitablement partagée parmi les individus. Ce constat interroge : comment se créent ces inégalités ? Comment infléchir cette tendance et faire la ville plus juste ?¦Apporter des réponses à cette problématique nécessite d'identifier les facteurs de causalités qui entrent en jeu dans le système de (re)production des inégalités urbaines. Le fonctionnement des marchés foncier et immobilier, la « tyrannie des petites décisions » et les politiques publiques à incidence spatiale sont principalement impliqués. Ces dernières, agissant sur tous les éléments du système, sont placées au coeur de ce travail. On va ainsi s'intéresser précisément à la manière dont les collectivités publiques pilotent la production de la ville contemporaine, en portant l'attention sur la maîtrise publique d'ouvrage (MPO) des grands projets urbains.¦Poser la question de la justice dans la fabrique de la ville implique également de questionner les référentiels normatifs de l'action publique : à quelle conception de la justice celle-ci doit- elle obéir? Quatre perspectives (radicale, substantialiste, procédurale et intégrative) sont caractérisées, chacune se traduisant par des principes d'action différenciés. Une méthodologie hybride - empruntant à la sociologie des organisations et à l'analyse des politiques publiques - vient clore le volet théorique, proposant par un détour métaphorique d'appréhender le projet urbain comme une pièce de théâtre dont le déroulement dépend du jeu d'acteurs.¦Cette méthodologie est utilisée dans le volet empirique de la recherche, qui consiste en une analyse de la MPO d'un projet urbain en cours dans la première couronne de l'agglomération lyonnaise : le Carré de Soie. Trois grands objectifs sont poursuivis : descriptif (reconstruire le scénario), analytique (évaluer la nature de la pièce : conte de fée, tragédie ou match d'improvisation ?) et prescriptif (tirer la morale de l'histoire). La description de la MPO montre le déploiement successif de quatre stratégies de pilotage, dont les implications sur les temporalités, le contenu du projet (programmes, morphologies) et les financements publics vont être déterminantes. Sur la base de l'analyse, plusieurs recommandations peuvent être formulées - importance de l'anticipation et de l'articulation entre planification et stratégie foncière notamment - pour permettre à la sphère publique de dominer le jeu et d'assurer la production de justice par le projet urbain (réalisation puis entretien des équipements et espaces publics, financement de logements de qualité à destination d'un large éventail de populations, etc.). Plus généralement, un décalage problématique peut être souligné entre les territoires stratégiques pour le développement de l'agglomération et les capacités de portage limitées des communes concernées. Ce déficit plaide pour le renforcement des capacités d'investissement de la structure intercommunale.¦La seule logique du marché (foncier, immobilier) mène à la polarisation sociale et à la production d'inégalités urbaines. Faire la ville juste nécessite une forte volonté des collectivités publiques, laquelle doit se traduire aussi bien dans l'ambition affichée - une juste hiérarchisation des priorités dans le développement urbain - que dans son opérationnalisation - une juste maîtrise publique d'ouvrage des projets urbains.¦Inner-city neighborhoods, poor outskirts, and peri-urban spaces with no amenities usually suffer from social and environmental inequalities, such as poverty, unemployment, and exposure to noise and industrial hazards. The observed persistence of these inequalities over time points to an underlying trend - namely, that access to proper living conditions is fundamentally unequal, thus eliciting the question of how such inequalities are effected and how this trend can be reversed so as to build a more equitable city.¦Providing answers to such questions requires that the causal factors at play within the system of (re)production of urban inequalities be identified. Real estate markets, "micromotives and macrobehavior", and public policies that bear on space are mostly involved. The latter are central in that they act on all the elements of the system. This thesis therefore focuses on the way public authorities shape the production of contemporary cities, by studying the public project ownership of major urban projects.¦The study of justice within the urban fabric also implies that the normative frames of reference of public action be questioned: what conception of justice should public action refer to? This thesis examines four perspectives (radical, substantialist, procedural, and integrative) each of which results in different principles of action. This theoretical part is concluded by a hybrid methodology that draws from sociology of organizations and public policy analysis and that suggests that the urban project may be understood as a play, whose outcome hinges on the actors' acting.¦This methodology is applied to the empirical analysis of the public project ownership of an ongoing urban project in the Lyon first-ring suburbs: the Carré de Soie. Three main objectives are pursued: descriptive (reconstructing the scenario), analytical (assessing the nature of the play - fairy tale, tragedy or improvisation match), and prescriptive (drawing the moral of the story). The description of the public project ownership shows the successive deployment of four control strategies, whose implications on deadlines, project content (programs, morphologies), and public funding are significant. Building on the analysis, several recommendations can be made to allow the public sphere to control the process and ensure the urban project produces equity (most notably, anticipation and articulation of planning and real- estate strategy, as well as provision and maintenance of equipment and public spaces, funding of quality housing for a wide range of populations, etc.). More generally, a gap can be highlighted between those territories that are strategic to the development of the agglomeration and the limited resources of the municipalities involved. This deficit calls for strengthening the investment abilities of the intermunicipal structure.¦By itself, the real-estate market logic brings about social polarization and urban inequalities. Building an equitable city requires a strong will on the part of public authorities, a will that must be reflected both in the stated ambition - setting priorities of urban development equitably - and in its implementation managing urban public projects fairly.

Nonempirical cluster-model study of the chemisorption of atomic hydrogen on the (111) surface of diamondlike crystals

The interaction of atomic hydrogen with C4H9, Si4H9, and Ge4H9 model clusters has been studied using all-electron and pseudopotential ab initio Hartree-Fock computations with basis sets of increasing flexibility. The results show that the effect of polarization functions is important in order to reproduce the experimental findings, but their inclusion only for the atoms directly involved in the chemisorption bond is usually sufficient. For the systems H-C4H9 and H-Si4H9 all-electron and pseudopotential results are in excellent agreement when basis sets of comparable quality are used. Besides, semiempirical modified-neglect-of-differential-overlap computations provide quite reliable results both for diamond and silicon and have been used to investigate larger model clusters. The results confirm the local nature of chemisorption and further justify the use of minimal X4H9 model clusters.

Chemisorption of atomic aluminum on Si(111): Evidence for an adsorbate-induced relaxation based on ab initio cluster-model calculations

Interaction models of atomic Al with Si4H9, Si4H7, and Si6H9 clusters have been studied to simulate Al chemisorption on the Si(111) surface in the atop, fourfold atop, and open sites. Calculations were carried out using nonempirical pseudopotentials in the framework of the ab initio Hartree-Fock procedure. Equilibrium bond distances, binding energies for adsorption, and vibrational frequencies of the adatoms are calculated. Several basis sets were used in order to show the importance of polarization effects, especially in the binding energies. Final results show the importance of considering adatom-induced relaxation effects to specify the order of energy stabilities for the three different sites, the fourfold atop site being the preferred one, in agreement with experimental findings.

Ab initio cluster-model study of the on-top chemisorption of F and Cl on Si(111) and Ge(111) surfaces

The interaction of atomic F and Cl with Si4H9 and Ge4H9 cluster models has been studied by using ab initio pseudopotentials and basis sets of increasing complexity. The results show that the effect of d orbitals is important in order to reproduce the experimental findings. However, the use of polarization functions in the atoms which are directly involved in the chemisorption bond leads to results which are very close to those obtained using extended basis sets. The local nature of the chemisorption bond is also interpreted by means of a Mulliken population analysis. For F-Si4H9 and Cl-Si4H9 the present results are in good agreement with previous ab initio all-electron calculations, and for the chemisorption of Cl on Si(111) and Ge(111) surfaces, good agreement is found with respect to the available experimental results as well as with previous slab calculations based on the local-density-functional formalism.

X-ray diffraction, thermal analysis, and Raman scattering study of K2BeF4 and comparation to other member of the (beta)-K2SO4 family with ferroelectric -paraelectric transition

Thermal analysis, powder diffraction, and Raman scattering as a function of the temperature were carried out on K2BeF4. Moreover, the crystal structure was determined at 293 K from powder diffraction. The compound shows a transition from Pna21 to Pnam space group at 921 K with a transition enthalpy of 5 kJ/mol. The transition is assumed to be first order because the compound shows metastability. Structurally and spectroscopically the transition is similar to those observed in (NH4)2SO4, which suggests that the low-temperature phase is ferroelectric. In order to confirm it, the spontaneous polarization has been computed using an ionic model.

A role for altered TLR gene expression in association with increased expression of CD200R in the induction of mucosal tissue CD4(+) Treg in aged mice following gavage with a liver extract along with intramuscular monophosphoryl lipid A (MPLA) injection.

Previous studies showed a fetal sheep liver extract (FSLE), in association with LPS, injected into aged (>20 months) mice reversed the altered polarization (increased IL-4 and IL-10 with decreased IL-2 and IFN-gamma) in cytokine production seen from ConA stimulated lymphoid cells of those mice. Aged mice show a >60% decline in numbers and suppressive function of both CD4(+)CD25(+)Foxp3(+)Treg and so-called Tr3 (CD4(+)TGFbeta(+)). Their number/function is restored to levels seen in control (8-week-old) mice by FSLE. We have reported at length on the ability of a novel pair of immunoregulatory molecules, members of the TREM family, namely CD200:CD200R, to control development of dendritic cells (DCs) which themselves regulate production of Foxp3(+) Treg. The latter express a distinct subset of TLRs which control their function. We report that a feature of the altered Treg expression following combined treatment with FSLE and monophosphoryl lipid A, MPLA (a bioactive component of lipid A of LPS) is the altered gene expression both of distinct subsets of TLRs and of CD200Rs. We speculate that this may represent one of the mechanisms by which FSLE and MPLA alter immunity in aged mice.

Yellow submarine of the Wnt/Frizzled signaling: submerging from the G protein harbor to the targets.

The Wnt/Frizzled signaling pathway plays multiple functions in animal development and, when deregulated, in human disease. The G-protein coupled receptor (GPCR) Frizzled and its cognate heterotrimeric Gi/o proteins initiate the intracellular signaling cascades resulting in cell fate determination and polarization. In this review, we summarize the knowledge on the ligand recognition, biochemistry, modifications and interacting partners of the Frizzled proteins viewed as GPCRs. We also discuss the effectors of the heterotrimeric Go protein in Frizzled signaling. One group of these effectors is represented by small GTPases of the Rab family, which amplify the initial Wnt/Frizzled signal. Another effector is the negative regulator of Wnt signaling Axin, which becomes deactivated in response to Go action. The discovery of the GPCR properties of Frizzled receptors not only provides mechanistic understanding to their signaling pathways, but also paves new avenues for the drug discovery efforts.

Catalan beauty and the transnational beast: Barcelona on screen

This article explores the case of Barcelona as paradigmatic global city in such transnational productions as Vicky Cristina Barcelona by Woody Allen (2008) and Biutiful by Alejandro González Iñárritu (2010). Allen"s film shows the extreme dilution that national and linguistic identity undergoes under foreign eyes in its rendition of a"hip Barcelona" for tourists"invaded" by transnational subjects in search of bourgeois pleasures. Maybe in pursuit of a more"real" city, Iñárritu"s Biutiful moves to the Barcelona of the immigrants and the undocumented, a transnational and paradoxical location inhabited by those who need to cross borders in order to survive. Through reference to the work of Manuel Castells, Saskia Sassen, Neil Smith and Michel De Certeau among others, we argue that neither of these representations of the city is more real or unreal than the other. In their drastically divergent ways, both films contribute their external perspectives to the imaginary construction of Barcelona as a fascinating global city and can be seen as a dyptich of a transnational Barcelona. Further, they contribute to the ongoing debate about the polarization between the local and the global, the construction of urban boarders inside cities through gentrification, the transformation of the places we (would like to) inhabit, and the translation of all these into visual terms.

Magnetoelectricity in the ferrimagnetic Cu2OSeO3: symmetry analysis and Raman scattering study

sublattices ferrimagnet Cu2OSeO3 with a cubic symmetry and a linear magnetoelectric effect. There is no spectroscopic evidence for structural lattice distortions below T-C=60 K, which are expected due to magnetoelectric coupling. Using symmetry arguments we explain this observation by considering a special type of ferrimagnetic ground state which does not generate a spontaneous electric polarization. Interestingly, Raman scattering shows a strong increase of electric polarization of media through a dynamic magnetoelectric effect as a remarkable enhancement of the scattering intensity below T-C. New lines of purely magnetic origin have been detected in the magnetically ordered state. A part of them are attributed as scattering on exchange magnons. Using this observation and further symmetry considerations we argue for strong Dzyaloshinskii-Moriya interaction existing in the Cu2OSeO3. (c) 2010 American Institute of Physics. [doi:10.1063/1.3455808]

The early IL-4 response to Leishmania major and the resulting Th2 cell maturation steering progressive disease in BALB/c mice are subject to the control of regulatory CD4+CD25+ T cells.

Susceptibility and development of Th2 cells in BALB/c mice infected with Leishmania major result from early IL-4 production by Vbeta4Valpha8 CD4+ T cells in response to the Leishmania homolog of mammalian RACK1 Ag. A role for CD4+CD25+ regulatory T cells in the control of this early IL-4 production was investigated by depleting in vivo this regulatory T cell population. Depletion induced an increase in the early burst of IL-4 mRNA in the draining lymph nodes of BALB/c mice, and exacerbated the course of disease with higher levels of IL-4 mRNA and protein in their lymph nodes. We further showed that transfer of 10(7) BALB/c spleen cells that were depleted of CD4+CD25+ regulatory T cells rendered SCID mice susceptible to infection and allowed Th2 differentiation while SCID mice reconstituted with 10(7) control BALB/c spleen cells were resistant to infection with L. major and developed a Th1 response. Treatment with a mAb against IL-4 upon infection with L. major in SCID mice reconstituted with CD25-depleted spleen cells prevented the development of Th2 polarization and rendered them resistant to infection. These results demonstrate that CD4+CD25+ regulatory T cells play a role in regulating the early IL-4 mRNA and the subsequent development of a Th2 response in this model of infection.

Release of vancomycin and teicoplanin from a plasticized and resorbable gelatin sponge: in vitro investigation of a new antibiotic delivery system with glycopeptides.

BACKGROUND: The aim of this study was to evaluate the efficacy of sustained release of vancomycin and teicoplanin from a resorbable gelatin glycerol sponge, in order to establish a new delivery system for local anti-infective therapy. MATERIALS AND METHODS: 60 plasticized glycerol gelatin sponges containing either 10 or 20% gelatin (w/v) were incubated in vancomycin or teicoplanin solution at 20 degrees C for either 1 or 24 h. In vitro release properties of the sponges were investigated over a period of 1 week by determining the levels of vancomycin and teicoplanin eluted in plasma using fluorescent polarization immunoassay. The rate constant and the half-life for the antibiotic release of each group were calculated by linear regression assuming first order kinetics. RESULTS: Presoaking for 24 h was associated with a significant increase in the total antibiotic release in all groups opposed to 1 h of incubation, except for the 10% sponges presoaked in teicoplanin. Doubling the gelatin content of the sponges from 10 to 20% significantly increased the total release of antibiotic load only in teicoplanin-containing sponges after 24 h incubation. In all corresponding groups investigated, release of vancomycin was more prolonged compared to teicoplanin, which allowed a gradual release beyond 5 days. The half-life (h +/- SEM) of both types of vancomycin-containing sponges was significantly prolonged by 24 h incubation in comparison to 1 h incubation (29.1 +/- 5.9 vs 5.9 +/- 1.0; p < 0.001, 30.0 +/- 2.1 vs 11.1 +/- 1.9; p < 0.001). However, neither doubling the gelatin content of the sponges nor a prolonged incubation was associated with a significantly prolonged delivery of teicoplanin. CONCLUSION: This study demonstrated a better diffusion-controlled release of vancomycin-impregnated glycerol gelatin sponges compared to those pretreated with teicoplanin. The plasticized glycerol gelatin sponge may be a promising carrier for the application of vancomycin to infected wounds for local anti-infective therapy.

Simple holographic polarogram

A new technique capable of obtaining quantitative values of the rotation angle of the polarization vector by using holography is presented. This is a two-stage holographic process; during the recording stage a hologram of the object of interest is obtained. The reference beam is composed of two beams that form a small angle between them and keep their polarization states at right angles to each other. In the reconstruction stage of the hologram, two images from the hologram are obtained along two different angles. As a result of the interference between these two images, a set of parallel fringes is formed at the image plane. The fringe contrast on the reconstruction is related to the angle of the polarization vector of the light at each position on the image plane. Measurements of the rotation of the polarization angle of a fraction of a degree were obtained. The main application of this technique is in the study of transient phenomena, where single-shot measurements are the only means of obtaining reliable data.

Kinship, ritual kinship and political milieus in an alpine Valley in 19th century

In my paper I will present some results about ritual kinship and political mobilization of popular groups in an alpine Valley: the Val de Bagnes, in the Swiss canton of Valais. There are two major reasons to choose the Val de Bagnes for our inquiry about social networks: the existence of sharp political and social conflicts during the 18th and the 19th century and the availability of almost systematic genealogical data between 1700 and 1900. The starting point of my research focuses on this question: what role did kinship and ritual kinship play in the political mobilization of popular groups and in the organization of competing factions? This question allows us to shed light on some other uses and meanings of ritual kinship in the local society. Was ritual kinship a significant instrument for economic cooperation? Or was it a channel for patronage or for privileged social contacts? The analysis highlights the importance of kinship and godparentage for the building of homogeneous social and political networks. If we consider transactions between individuals, the analysis of 19th century Val de Bagnes gives the impression of quite open networks. Men and women tried to diversify their relations in order to avoid strong dependency from powerful patrons. Nevertheless, when we consider the family networks, we can notice that most relations took place in a structured social space or a specific "milieu", were intense contacts enhanced trust, although political allegiances and social choices were not fully predictable on the basis of such preferential patterns. In a politically conflictual society, like 19th century Bagnes, ritual kinship interacted with kinship solidarities and ideological factors shaping dense social networks mostly based on a common political orientation. Such milieus sustained the building of political factions, which show surprising stability over time. In this sense, milieus are important factors to understand political and religious polarization in 19th century Switzerland.