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In metallurgical grade Si (MG-Si), the coal (B) and charcoal (P) contents are on average above 30 ppm as the carbon reduction materials used in the arc furnace are either rich in B or in P. A decrease of both impurities by a factor of 3 using purer raw materials would allow for the direct production of the upgraded metallurgical grade (UMG).This would significantly improve the efficiency of the resulting photovoltaic (PV) cells made with the refined solar grade silicon (SoG-Si) or massively decrease the costs of Si purification by shortening the number of steps needed for reaching B and P contents below 1 ppm requested for the SoG-Si used for the PV cells. A composite C/SiO2 briquette fulfilling the purity targets for the direct production of UMG-Si in the arc furnace was developed. The composite contains several carbon materials with different levels of reactivities and quartz sand. The raw materials aspects, the paste and briquette preparation, as well as the final carbonization step are discussed. The finished briquettes are free of volatiles and are mechanically and thermally very stable, thus, ensuring stable arc furnace charges with minimum losses of dust and SiO gas. Semi-industrial trials including the downstream purification steps for the production of SoG-Si by a metallurgical low-cost route are contemplated.

In metallurgical grade Si (MG-Si), the coal (B) and charcoal (P) contents are on average above 30 ppm as the carbon reduction materials used in the arc furnace are either rich in B or in P. A decrease of both impurities by a factor of 3 using purer raw materials would allow for the direct production of the upgraded metallurgical grade (UMG).This would significantly improve the efficiency of the resulting photovoltaic (PV) cells made with the refined solar grade silicon (SoG-Si) or massively decrease the costs of Si purification by shortening the number of steps needed for reaching B and P contents below 1 ppm requested for the SoG-Si used for the PV cells. A composite C/SiO2 briquette fulfilling the purity targets for the direct production of UMG-Si in the arc furnace was developed. The composite contains several carbon materials with different levels of reactivities and quartz sand. The raw materials aspects, the paste and briquette preparation, as well as the final carbonization step are discussed. The finished briquettes are free of volatiles and are mechanically and thermally very stable, thus, ensuring stable arc furnace charges with minimum losses of dust and SiO gas. Semi-industrial trials including the downstream purification steps for the production of SoG-Si by a metallurgical low-cost route are contemplated.

Mercury is a contaminant of great concern in the marine environment, particularly in coastal environments where the formation of methylmercury (MeHg) in aquatic sediments, and its subsequent bioaccumulation in edible aquatic organisms (mainly fish), presents a major pathway for human exposure to MeHg. Consequently, it is important to determine the factors controlling MeHg production in sediments, especially in environments exposed to anthropogenic influence. This study investigates some of the main geochemical factors affecting the speciation and distribution of mercury in estuarine sediments from two highly industrialized macrotidal salt marsh/mudflat systems in the Seine estuary, France, and in the Medway estuary, UK. Obtained data revealed that the entire sediments core from a rapidly accreting mudflat in the Seine estuary (the analysed sediment column of 170 cm has accumulated over the last 10-50 years) was contaminated with mercury, at concentrations which are 10-50 times higher than the Hg background for sediments of the Seine basin. In the mudflat in the Medway estuary, characterized by a slow sedimentation rate (400 cm of the sediment column has accumulated over the approximately last 800 a), the near-surface sediments were significantly more contaminated (10-40 times) than sediments at greater depths, characterized with pre-industrial Hg value. Geochemical conditions in the surface sediments of the Medway mudflat, which are characterized with stable redox conditions (about -200 mV), which is generally favourable for Hg methylation, whereas near-surface sediments of the Seine mudflat, is characterized by more oxidizing redox conditions )about +100 mV). Which is generally less conductive to Hg methylation. Consequently, MeHg concentration in the upper 10 cm of the sediment column was about 4 times higher in the Medway than in the Seine mudflat, in spite of the similar total Hg concentrations. In surface sediments, where Hg is actively methylated, MeHg variability was associated with activity of sulphate-reducing microorganisms (SRM) and the presence of acid volatile sulphides (AVS). A strong correlation was observed between MeHg and AVS in sediments of these mudflats, what may be a consequence of the common origin of AVS and MeHg (both produced by microorganism activity), but also can be derived from the ability of Fe monosulfides to adsorb and thus stabilize solid phase MeHg.

For many years anode dusting has been an issue for aluminum producers. Suspended carbon particles enhance the electrical resistivity of the cryolite bath, setting off a chain reaction of adverse effects for the pot. Many studies have documented the negative influence of carbon dust on current efficiency or bath temperature which are indirect effects of contaminated bath. The dependence of bath resistivity on the amount and on the size of carbon particles is poorly understood though. Tube-type cell experiments were performed to determine the electrical resistivity at 980 °C of standard bath mixtures added with carbon dust. The carbon content ranged from 0.06 to 1.01% in weight with mean particle size of 2 μm. A bath resistivity increase of 70% was measured when comparing the bath with the lowest carbon concentration with the one with the highest. From a bath with a carbon content of 0.06% to a one with 0.16%, the change in resistivity was equal to 13%. Thus the difference in bath resistivity between a benchmark bath with 0.03% carbon content and a bath from a dusty pot will be even larger. These results agree with variations of voltage measured during the ACD squeeze of groups of clean and dusty pots.

Background, Aim and Scope The sulphidization process in relatively clean sediments sampled in a mudflat of the Authie estuary (located in Northern France) has been studied by coupling geochemical expertise and the use of fatty acids (FAs) as biochemical markers. Materials and Methods: Three sediment cores have been sampled in September 2003, November 2003 and May 2004, and cut every 2 cm in the field under nitrogen atmosphere so as to prevent any oxidation of reduced species. In the solid phase, reduced sulphur compounds, e.g. AVS (Acid Volatile Sulphides) and CRS (Chromium Reducible Sulphur) [including also the calculation of the degree of sulphidization (DOS) and the degree of pyritization (DOP)], and fatty acids have been carried out. Eh, pH, metal species (mostly iron and manganese), dissolved S(-II) and sulphate have also been determined in the porewaters. Results: The sediment cores display a lot of differences due to the high sedimentation rate and the seasonal evolution as well. The presence of Mn2+, Fe2+, S(-II) and the decrease of the redox potential and the concentration of sulphates clearly indicate early diagenetic transformations promoted by the bacterial activity. Acid Volatile Sulphides are produced in the first cm and are stabilized with depth. A rapid decrease of FAs concentrations in September and May has also been pointed out owing to a rapid consumption of the labile organic matter. Several categories of FAs have been separated and most of them belong here to the saturated and monounsaturated groups. In the saturated group, branched chain FAs, iso and anteiso C15:0 are predominant and represent the bacterial imprint in the sediments. Maximum proportions are observed between 5 and 10 cm in September, and between 13 and 17 cm in November and May. Discussion: As sulphate concentrations remain high in the porewater, the limitation of the sulphidization process in our sediments must be due to a lack of labile organic matter input. The presence of pyrite in our sediment is bound to its formation at the water-sediment interface, where partial reoxidation may take place. However, at deeper depths, pyritization processes does not continue any more. Presence of maximum, dissolved S(-II) concentrations have been observed, simultaneously with maximum proportion relative to total FAs of iso and anteiso C15:0, and, in September, with an increase in proportions of C18:1ω7. This indicates the presence of sulphate-reducing bacterial activity at the time when the sediments were sampled. However, no close correspondence between bacterial FAs concentrations and S(-II) concentrations has been found. Conclusions: In each core, the sulphidization process is not complete, and this is probably due to the lack of biodegradable organic matter, which appears as the limiting factor from a qualitative point of view. S(-II) production in porewaters is linked with the activity of sulphate-reducing bacteria. Seasonal effects have also been pointed out and, especially, a more important input of diatom organic matter in May when compared to September and November. Recommendations and Perspectives: Fatty acid analyses represent an original and a useful tool for a better understanding of an early diagenetic process in the first cm of the sediments. More studies should be carried out associating inorganic chemical parameters and chemical biomarkers for pointing out stronger and more reproducible relations. Moreover, the use of microcosms in our group is on the way to take into account the kinetics of the organic matter degradation during the early diagenesis.

Resume Durant ses 30 premieres annees de parution, de 1906 a 1937, les Annales de Paleontologie ont presente, a l'instigation de Marcellin Boule, une suite d'articles apparemment anonymes, devolus aux Types du Prodrome de d'Orbigny. Ces articles, difficiles a citer car pour la plupart non signes et parfois meme non titres, redefinissent et illustrent les especes que d'Orbigny avait etablies en 1850 et 1852 dans son Prodrome de Paleontologie stratigraphique universelle , mais tres brievement et sans figuration. Il s'agit en fait d'une œuvre collective, restee largement inachevee mais qui totalise cependant 510 pages de texte et 139 planches photographiques, au cours desquelles les redacteurs, Armand Thevenin, Ferdinand Canu et Jean Cottreau, ont a eux trois redefini plus de 1000 especes (mollusques, brachiopodes, echinodermes, bryozoaires, madreporaires et poriferes) s'echelonnant du Silurien inferieur au Neocomien, selon les etages stratigraphiques alors adoptes par d'Orbigny. Cette redefinition des types du Prodrome constitue une somme dont l'utilite peut se mesurer au nombre des references qui y ont ete faites et s'y font encore dans les travaux de paleontologie des invertebres, et ceci malgre le choix discutable de quelques-uns des specimens de reference alors retenus.

Resume Quatre campagnes de fouilles, executees de 1983 a 1986, ont apporte une foison d’observations entierement nouvelles sur ce site paleontologique remarquable, qui etait reste jusqu’alors durablement delaisse et pour l’essentiel inexplore. La presente communication a pour but d’en presenter une synthese. Les quelque 12 m d’epaisseur stratigraphique fouilles ont permis de preciser la succession des facies sur la quasi-totalite des horizons conserves, avec leurs faunes correspondantes. Ces observations revelent une forte homogeneite d’ensemble, a la fois dans les caracteres lithologiques, taphonomiques et paleobiologiques, ce qui traduit une assez forte constance des conditions globales d’environnement. Les lithofacies sont des marnes schisteuses revelatrices d’anciens paleosubstrats meubles, a forte dominante argileuse (60 a 70 % de montmorillonite et moins de 30 a 40 % de carbonate de calcium, siderite et limonite). Les peuplements sont composes presque exclusivement d’organismes pelagiques, nectopelagiques ou mesopelagiques (nageant en pleine eau ou infeodes a des milieux algaires libres) ; ils ne comprennent que tres peu d’organismes benthiques. Les conditions d’environnement, franchement marines, devaient correspondre a une tranche d’eau d’environ 200 m ; les tranches d’eau superieures et moyennes, ou vivaient la plupart des organismes, devaient etre normalement agitees, oxygenees et eclairees ; a l’inverse, les fonds devaient etre extremement calmes et tres peu oxygenes, en zone aphotique, ce qui a ete favorable a la mineralisation des tissus mous.

Solid Au and Ag microelectrodes for both, model and in situ voltammetric measurements, have been designed and tested. Amalgamation procedure and the parameters of measurement procedure are discussed. Differences between gold and silver electrodes were studied. Silver electrodes showed more stable behaviour and were used prevalently for calibration and in situ measurements. Calibration of a 30-&micro ; ; ; m diameter Ag electrode for Mn(II), Fe(II), I(-I) and S(-II) showed good linearity with reasonable confidence intervals, necessary for quantification of the signals obtained in situ, with average sensitivity of 0.05, 0.01, 0.16 and 1.10 nA/(&micro ; ; ; mol L-1) and minimal detection limit of 3.5, 28, 0.3 and 0.05 &micro ; ; ; mol L-1, respectively. Additional checking of the electrode sensitivity with the reduction peaks of oxygen is proposed.

Standard work aims to ensure that reliable analysis methods are available. ISO standards are commercially important and are recognised and used by suppliers and customers around the world. Reliable analysis enables the suppliers to describe their materials using common standards for well-established material properties, and the standards are a support for smelters when evaluating and comparing sources of materials.

D’Orbigny was more interested in the discontinuities of life history than in the origin of species. He looked for reference points to correlate geological strata and to reconstruct their history. This allowed him to formalise the concept of stratigraphic stage and to propose the first geological time scale. Therefore, one of the results was that he was unjustly considered as one of the leaders of the creationism school, because he used the ambiguous term ‘creation’ to designate the renewal of fauna after catastrophic events, but without providing a definition and with a meaning that was probably different from those of his successors.

The numerous travels made by Alcide d’Orbigny during about twenty years, between 1834 and 1855, essentially for biostratigraphical investigations, were almost never recalled in the scientific papers. The data contained in his various publications concerning the palaeontological sites where he collected himself fossil samples allowed to list nearly 400 localities where he worked in France and adjacent regions, mainly on Jurassic and Cretaceous deposits.

The whole formed by his Paleontologie francaise, his Prodrome, and his Cours elementaire, which are closely linked, constitutes one of the major parts of Alcide d’Orbigny’s scientific production, in which he exposed his concept of Palaeontology as a science closely related with Zoology and as an indispensable tool for Stratigraphy. The result was a remarkable impulsion for palaeontological and stratigraphical research, which from that time developed on new scientific foundations. Two annexes complete this communication, the first concerning the ‘Comite de la Paleontologie francaise’ (1860–1893), the second specifying the publication dates of four volumes of the Paleontologie francaise.

Resume De recentes recherches effectuees dans l’assise superieure du Calcaire massif du Monte Cucco, dont la lithostratigraphie est ici detaillee, a permis d’y decouvrir une faune d’âge sinemurien, assez diversifiee et fortement dominee par les gastropodes : elle comprend, outre quelques madreporaires solitaires, brachiopodes, bivalves et ammonoides, 18 especes de gastropodes appartenant aux super-familles des Pleurotomarioidea, Fissurelloidea, Amberleyoidea, Neritoidea, Loxonematoidea, Cerithioidea, Nerineoidea, Littorinoidea et Acteonoidea, dont dix especes nouvelles. L’analyse detaillee de cette faune de gastropodes revele des affinites paleobiogeographiques assez marquees avec le Sinemurien de Sicile. Du point de vue paleoecologique, cette faune de gastropodes se revele indicatrice d’un paleomilieu marin franc, en zone photique mais a hydrodynamisme faible, donc probablement situe dans l’etage infralittoral inferieur ou a la partie superieure de l’etage circalittoral.

A method based on solid-phase microextraction and gas chromatography nitrogen-phosphorus detector for the determination of common organonitrogen pesticides (ONPs) in aqueous samples was described. Three kinds of commercially available coated fused-silica fibres were compared: 100 µm PDMS, 85 µm PA, and 65 µm CW-DVB; 65 µm CW-DVB was the most sensitive fibre coating for the analytes' determination. The extraction time, the stirring, the content of salt, and the content of organic solvents were found to have a significant influence on extraction efficiency. The optimised conditions were 65 µm CW-DVB fibre, 40 min extraction time, with rapid stirring and concentration of NaCl was fixed at 0.25 g/mL. The linear range was 0.1-100 µg/L for most of the compounds. The limits of detection (LODs) ranged from 0.02 mg/L (for trifluralin, simazine, terbuthylazine, cyanazine, and pendimethalin) to 0.08 µg/L (for terbutryn) and RSD % of repeatability were for most of the compounds below 10%. Thus the maximum level set b...

Resume Les vampyromorphes, ordre voisin des octopodes, n’etaient jusqu’ici connus avec certitude que dans la nature actuelle, en eaux oceaniques profondes. Leur presence des le Jurassique moyen se trouve attestee par une vingtaine de specimens du Callovien inferieur de la Voulte-sur-Rhone (Ardeche), qui en possedent les caracteres essentiels : huit bras sessiles relies par un velum et armes d’une rangee de ventouses encadrees de cirres, une paire de tentacules brachiaux, des yeux lateraux bien developpes, un organe de soutien interne (gladius) non calcifie, une paire de nageoires supero-posterieures, deux organes lumineux postero-dorsaux, pas de poche a encre. Ces specimens, pour lesquels sont ici proposes les nouveaux genre et espece Vampyronassa rhodanica, different cependant des vampyromorphes actuels par leurs deux premiers bras sessiles dorsaux nettement plus longs que les autres, par le plus grand developpement de leur entonnoir et par leur tronc fusele, plus allonge. La presence d’un vampyromorphe deja bien caracterise au Jurassique moyen laisse supposer pour cet ordre de cephalopodes une origine beaucoup plus ancienne encore. Quelques considerations sont apportees sur son mode ce vie tres probablement mesopelagique. Une argumentation critique est presentee au sujet de trois grandes especes du Jurassique superieur d’Allemagne comparables a des teuthoides et precedemment attribuees aux vampyromorphes.

Mapping of Phanerozoic rocks at 1:250,000 scale by joint teams from the Saudi Arabian Deputy Ministry for Mineral Resources and the Bureau de Recherches Géologiques et Minières since 1980 has covered most of the Jurassic outcrops in central Saudi Arabia. Stratigraphic, sedimentologic and paleogeographic studies provided a precise framework for collected gastropod faunas that could be calibrated against ammonite zones and sequence-stratigraphic zones. Of more than 600 samples collected, about 440 gastropod specimens could be determined on at least a generic level. Their age range is from Bajocian to Oxfordian–Kimmeridgian. They correspond to 26 genera and 35 species from the Euomphalidae, Ataphridae, Pseudomelaniidae, Coelostylinidae, Procerithiidae, Nerineidae, Purpurinidae, Aporrhaidae, Naticidae, Acteonidae, Retusidae, and Akeridae families. Twelve species are new, and three (Kosmomphalus and Bifidobasis in the Euomphalidae, and Striatoonia in the Pseudomelaniidae) were proposed for new taxa of generic or subgeneric rank. Most of the identified species are of Middle Jurassic age, mainly Bathonian and Callovian and only six are Late Jurassic. All species are typical of an internal platform environment (upper infralittoral), in a lagoonal to back-reef setting, but some also colonized the external platform in the lower infralittoral fore-reef zone. Paleogeographically, most of the species are related to European and Sinai faunas; only seven are equivalent to North African or East African faunas, and one only was reported from Madagascar.

Treatment of the carbamate 2a by i -amyl nitrite and TMSCl in presence of a reduced amount of pyridine, followed by decomposition of the resulting nitroso derivative 3a with activated alumina afforded in high yield the pure, crystalline, diazosulfone 1a , a process which could be extended to the preparation of the parent diazosulfone 1b .

The use of dilute HCI for the selective extraction of mercury from suboxic and anoxic sediments has been evaluated. The effect of acid concentration on the extraction of Hg and on the recovery of aqueous Hg preextraction spikes from sediments containing various amounts of AVS has been studied. The results obtained by using 1 M HCI as extractant indicated that acid-soluble Hg may react with H{sub 2}S released from AVS phases (e.g., FeS, MnS) and precipitate in the form of HgS. The modeling of Hg speciation in HCI solutions in the presence of sulfide predicted the HgS(s) precipitation in 1 M HCI, observed experimentally. The precipitation of HgS(s) was found to be considerably lower when greater HCI concentrations were used for Hg extraction. The modeling calculations confirmed that the extent of HgS(S) formation in the solution was controlled by the applied HCI concentration. The difference between HCI-soluble Hg fraction in an estuarine sediment core extracted by 1 M and 6 M HCI was consistent with the model experiments. These results suggest that the use of 1 M HCI extraction procedures must be questioned for methodological artifacts and that 6 M HCI could advantageously replace 1 M HCI for extracting Hgmore » in the presence of AVS.« less

An unsymmetrical koiland 5 based on the double fusion of two different calix[4]arenes by two silicon atoms has been prepared and structurally characterised. Using p-xylene and phenylpropyne as symmetrical unsymmetrical connectors, respectively, directional 1-D inclusion networks have been obtained and structurally characterised by X-ray diffraction methods on single crystals. In both cases, the 1-D networks were packed in a parallel fashion. However, the linear arrays were oriented in opposite directions, thus leading to non-directional systems.

Existing methods for total mercury and methylmercury determination in sediment and porewaters were improved by applying open microwave heating for extraction of Hg species from the sample and decomposition of MeHg prior to detection as Hg(II) by CV AFS. It was shown that nitric acid can quantitatively leach Hg from sediment, already at a low microwave power (30 W, 5 min). Methylmercury can be quantitatively leached from sediment by dilute sulphuric acid (1 mol/L) at a power of 60 W during 5 minutes, without being decomposed. So obtained extract can be further distilled with a reduced possibility for artefac- tual MeHg formation, as it contains much lower levels of inorganic Hg, compared to the original sediment. Microwave-assisted BrCl oxidation was shown to be more effective for decomposition of MeHg and stable organomercury complexes in water solu- tions (sediment distillate and porewater), as compared with BrCl oxidation at room-temperature. Therefore, the application of low-power microwave digestion can significantly improve determination of Hg species in sediment and porewater, both in terms of time and efficiency.

The diazolactone 6b rearranges by treatment with CF3CO2H to give the ketolactone 3b, that, by sequential treatment with lithiated ethyl diazoacetate and AcOH, afforded the ketodiester 15.

The stereochemical course of the osmium-mediated bis-hydroxylation of the allylic derivative 6c, whose the structure is closely related to that of a C-1/C-7 fragment of the title aglycone, has been established unambiguously by X-ray analysis of a carboxylic acid derived from one of the two diastereomeric diols which formed.

During four surveys covering various hydrodynamic conditions samples were collected in the Seine river estuary for the study of dissolved and particulate manganese. A new analytical method for direct determination of dissolved manganese was used in this study (atomic absorption spectrometry with Zeeman non-specific absorption correction). Generally, dissolved manganese versus salinity curves exhibits a peak concentration in the low salinity zone. Speciation studies of dissolved and particulate manganese have been performed in order to establish a model for manganese behaviour in the Seine estuary. Taking into consideration the solution composition as well as the values of stability constants of the complexes, dissolved manganese speciation has been calculated using an equilibrium Speciation program. Sequential extraction procedures (Tessier's scheme) have been applied to assess the manganese distribution in solid samples (sediment, suspended matter). Operational nature of empiricism inherent to these procedures has been partly eliminated by determining physicochemical form of Mn by electron spin resonance owing to the paramagnetic properties of manganese. This study has allowed us to show that manganese behaviour in the Seine estuary is strongly influenced, (i) in solid samples, by the presence of calcium carbonate which stabilise the Mn(II) form; (ii) in solution, by the increase of salinity, calcium, magnesium and suspended matter concentrations, by complexes formation and by diffusion from sediments to water.

Thermal intramolecular Diels-Alder cyclisation of the ketone C-1 proceeds through an exo transition state to give the ketone CAT-2.

Constant potential electrolysis of several glycosyl donors such as substituted phenyl 2,3,4,6-tetra-O-acetyl, benzoyl or benzyl-1-thio-β-D-gluco or galactopyranosides in dry acetonitrile in the presence of various primary, secondary or tertiary alcohols performed in an undivided cell, gave preferentially β-linked saccharides in moderate to good yields according to the nature of the protective groups on the sugar moiety. 2-Deoxy-2-phthalimido-1-thio-β-D-gluco derivatives gave the β-glucosides selectively in excellent yields. It was found, as expected, that substitution of the phenyl group with methoxy or methyl radicals facilitates the electrochemical glycosylation reaction by lowering the oxidation potentials of the corresponding thioglycosides.

Constant potential electrolysis of the glycosyl donors p-methylphenyl 2,3,4,6-tetra-O-benzyl-1-thio-β-D-glucopyranoside (1) and p-methylphenyl 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-1-thio-β-D-glucopyranoside (4) in dry acetonitrile in the presence of various primary and secondary sugar alcohols, performed in an undivided cell, gave β-linked disaccharide derivatives selectively in good yields. Oxidative coupling of p-methoxyphenyl 2,3,4-tri-O-benzyl-1-thio-β-L-fucopyranoside (2 1) with p-methoxybenzyl 4,6-O-benzylidene-2-deoxy-2-phthalimido-β-D-glucopyranoside (16) gave selectively the α-linked disaccharide 22 in good yield.

D-Glucose and D-Galactose are transformed to the corresponding α and β -Methyl D-Glucofuranosides in good yields using methanol and Ferric chloride as catalyst.

Oxidation of a THF solution of Li[HC(PPh 2 ) 2 ] with iodine affords the isomeric products Ph 2 P-CH=PPh 2 -PPh 2 =CH-PPh 2 2, (Ph 2 P) 2 C=PPh 2 -CH 2 -PPh 2 4 and (Ph 2 P) 2 CH-CH(PPh 2 ) 2 1, which result from P-P, P-C and C-C coupling, respectively. The latter pathway has now been established for the first time and the crystal structure of the resulting new chiral tetraphosphine 1 has been determined by X-ray diffraction.

It is shown that the S-benzyl substituent, in the S-benzyl sulfonium perchlorate 2 derived from Eliel's oxathiane, has an axial position in the solid state (X Ray analysis of a single crystal) as well as in solution (2D 1H NMR), probably due to 1-3-anomeric effect between the lone-pairs of oxygen and sulfur.

A general study of manganese and zinc in both dissolved and particulate forms in waters from the Seine river, its estuary and the Bay of Seine (in northern France) has been undertaken in order to investigate their fate and transport processes in riverine, estuarine and coastal environments. These samples have been analyzed using graphite-furnace atomic absorption spectroscopy (GFAAS), inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and differential pulse anodic stripping voltammetry (DPASV). In this work, we have considered the different parameters (salinity, pH, temperature and total suspended matter) which may influence the metal distribution in the estuary, and have surveyed the evolution of these metals (with numerous soluble organic and inorganic ligands) in aqueous phases and their interaction with the various inorganic and organic solid fractions which compose the particles. The results show that dissolved Mn and Zn are mainly influenced by salinity. Furthermore, their variability is governed by temporal and spacial changes in tidal stress. Indeed, the distributions of dissolved Mn and Zn are linked to the internal properties of particles and the flow of sediments regulated by the tidally-induced perturbations in the estuary bed. Since the cause of these observations is in connection with the interactions between the liquid phase and the solids present, we have also undertaken the chemical speciation of Mn and Zn in the particles. The results obtained confirm the non-conservative behavior of these two metals. Owing to the paramagnetic properties of Mn, we have been able to analyze particles using electron spin resonance spectroscopy in order to gain further information about the nature of Mn compounds, their oxidation states and their combinations.

The X-ray structures of the β-substituted-pyrrole, its nickel(II) complex (NiTMOBP), and the nickel(II) derivative are reported. The synthesis of the free base H 2 TPFPOBP is also described. All these molecules are nonplanar, displaying saddle-shaped conformations

International audience; The Scheldt River system is located in northern France, Belgium and the Netherlands and includes a dense network of rivers, which contributed to the urban and industrial development in this area. Three sediment cores, collected in the Upper Scheldt River (Helkijn) and two of its tributaries (the Lys River at Wervik and the Espierre Canal), were analysed for n-alkanes and polycyclic aromatic hydrocarbons (PAHs). Total n-alkane and PAH concentrations in all the sampled cores ranged from 2.8 to 29 mg kg -1 and from 4.9 to 96 mg kg -1, respectively. The contributions of biogenic, petrogenic and pyrolytic sources were investigated using n-alkane indexes and PAH diagnostic ratios. n-alkane chromatograms were characterized by the predominance of odd over even long chain n-alkanes (produced by terrestrial plants) and by the occurrence of a broad unresolved complex mixture (UCM) which evidenced biodegraded petroleum residues. For the three studied cores, correlations between the concentrations of UCM and n-alkanes (both expressed on an organic carbon basis) indicated a common origin or similar pathways of these allochtonous compounds to the aquatic environment. Wervik sediments were distinguished by higher n-alkane concentrations and by a major aquatic biogenic source for low molecular weight n-alkanes. The prevalence of combustion-derived PAHs was indicated by the high contribution of four, five and six rings compounds and was confirmed by isomer ratios. Higher levels of low molecular weight PAHs in Helkijn surface sediments suggested modest petrogenic inputs in this navigable canal. High PAH concentrations in Espierre sediments could be explained by a major historical contamination from urban and industrial emissions.

The structure and magnetic properties of yttrium diphthalocyanine [${\mathrm{YPc}}_{2}$]\ensuremath{\cdot}${\mathrm{CH}}_{2}$${\mathrm{Cl}}_{2}$ are reported. Phthalocyanine macrocycles are stacked above each other in one direction, with a staggered angle of 45\ifmmode^\circ\else\textdegree\fi{}. One-dimensional organic ferromagnetism is emphasized for the first time, and discussed on the basis of an orbitally degenerate model. A comparison with the behavior of the nonsolvated derivative \ensuremath{\alpha}-${\mathrm{YPc}}_{2}$ is reported.

D-Glucose and D-Galactose are transformed to the corresponding α and β -Methyl D-Glucofuranosides in good yields using methanol and Ferric chloride as catalyst.