Cell locations for AQP1, AQP4 and 9 in the non-human primate brain.

The presence of three water channels (aquaporins, AQP), AQP1, AQP4 and AQP9 were observed in normal brain and several rodent models of brain pathologies. Little is known about AQP distribution in the primate brain and its knowledge will be useful for future testing of drugs aimed at preventing brain edema formation. We studied the expression and cellular distribution of AQP1, 4 and 9 in the non-human primate brain. The distribution of AQP4 in the non-human primate brain was observed in perivascular astrocytes, comparable to the observation made in the rodent brain. In contrast with rodent, primate AQP1 is expressed in the processes and perivascular endfeet of a subtype of astrocytes mainly located in the white matter and the glia limitans, possibly involved in water homeostasis. AQP1 was also observed in neurons innervating the pial blood vessels, suggesting a possible role in cerebral blood flow regulation. As described in rodent, AQP9 mRNA and protein were detected in astrocytes and in catecholaminergic neurons. However additional locations were observed for AQP9 in populations of neurons located in several cortical areas of primate brains. This report describes a detailed study of AQP1, 4 and 9 distributions in the non-human primate brain, which adds to the data already published in rodent brains. This relevant species differences have to be considered carefully to assess potential drugs acting on AQPs non-human primate models before entering human clinical trials.

Cell locations AQP1, AQP4 and 9 in the non-human primate brain

Rapport de synthèse : La présence de trois canaux d'eau, appelés aquaporines AQP1, AQP4 et AQP9, a été observée dans le cerveau sain ainsi que dans plusieurs modèles des pathologies cérébrales des rongeurs. Peu est connu sur la distribution des AQP dans le cerveau des primates. Cette connaissance sera utile pour des futurs essaies médicamenteux qui visent à prévenir la formation des oedèmes cérébraux. Nous avons étudié l'expression et la distribution cellulaire des AQP1, 4 et 9 dans le cerveau primate non-humain. La distribution des AQP4 dans le cerveau primate non-humain a été observée dans des astrocytes périvasculaires, comparable à l'observation faite dans le cerveau du rongeur. Contrairement à ce qui a été décrit chez le rongeur, l'AQPI chez le primate est exprimée dans les processus et dans les prolongations périvasculaires d'un sous-type d'astrocytes, qui est avant tout localisé dans la matière blanche et dans la glia limitans et qui est peut-être impliqué dans l'homéostasie de l'eau. L'AQPI a aussi été observée dans les neurones qui innervent des vaisseaux sanguins de la pie-mère, suggérant un rôle possible dans la régularisation de la vascularisation cérébrale. Comme décrit chez le rongeur, le mRNA et les protéines de l'AQP9 ont été détectés dans des astrocytes et dans des neurones catécholaminergiques. Chez le primate, des localisations supplémentaires ont été observées dans des populations de neurones placées dans certaines zones corticales. Cet article décrit une étude détaillée sur la distribution des AQP1, 4 et 9 dans le cerveau primate non-humain. Les observations faites s'additionnent aux data déjà publié sur le cerveau du rongeur. Ces importantes différences entre les espèces doivent être considérées dans l'évaluation des médicaments qui agiront potentiellement sur des AQP des primates non-humains avant d'entrer dans la phase des essais cliniques sur des humains.

Fate of the herbicide glyphosate and its metabolite AMPA in soils and their transfer to surface waters: A multi-scale approach in the Lavaux vineyards, western Switzerland

The use of herbicides in agriculture may lead to environmental problems, such as surface water pollution, with a potential risk for aquatic organisms. The herbicide glyphosate is the most used active ingredient in the world and in Switzerland. In the Lavaux vineyards it is nearly the only molecule applied. This work aimed at studying its fate in soils and its transfer to surface waters, using a multi-scale approach: from molecular (10-9 m) and microscopic scales (10-6 m), to macroscopic (m) and landscape ones (103 m). First of all, an analytical method was developed for the trace level quantification of this widely used herbicide and its main by-product, aminomethylphosphonic acid (AMPA). Due to their polar nature, their derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) was done prior to their concentration and purification by solid phase extraction. They were then analyzed by ultra performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The method was tested in different aqueous matrices with spiking tests and validated for the matrix effect correction in relevant environmental samples. Calibration curves established between 10 and 1000ng/l showed r2 values above 0.989, mean recoveries varied between 86 and 133% and limits of detection and quantification of the method were as low as 5 and 10ng/l respectively. At the parcel scale, two parcels of the Lavaux vineyard area, located near the Lutrive River at 6km to the east of Lausanne, were monitored to assess to which extent glyphosate and AMPA were retained in the soil or exported to surface waters. They were equipped at their bottom with porous ceramic cups and runoff collectors, which allowed retrieving water samples for the growing seasons 2010 and 2011. Results revealed that the mobility of glyphosate and AMPA in the unsaturated zone was likely driven by the precipitation regime and the soil characteristics, such as slope, porosity structure and layer permeability discrepancy. Elevated glyphosate and AMPA concentrations were measured at 60 and 80 cm depth at parcel bottoms, suggesting their infiltration in the upper parts of the parcels and the presence of preferential flow in the studied parcels. Indeed, the succession of rainy days induced the gradual saturation of the soil porosity, leading to rapid infiltration through macropores, as well as surface runoff formation. Furthermore, the presence of more impervious weathered marls at 100 cm depth induced throughflows, the importance of which for the lateral transport of the herbicide molecules was determined by the slope steepness. Important rainfall events (>10 mm/day) were clearly exporting molecules from the soil top layer, as indicated by important concentrations in runoff samples. A mass balance showed that total loss (10-20%) mainly occurred through surface runoff (96%) and, to a minor extent, by throughflows in soils (4%), with subsequent exfiltration to surface waters. Observations made in the Lutrive River revealed interesting details of glyphosate and AMPA dynamics in urbanized landscapes, such as the Lavaux vineyards. Indeed, besides their physical and chemical properties, herbicide dynamics at the catchment level strongly depend on application rates, precipitation regime, land use and also on the presence of drains or constructed channels. Elevated concentrations, up to 4970 ng/l, observed just after the application, confirmed the diffuse export of these compounds from the vineyard area by surface runoff during main rain events. From April to September 2011, a total load of 7.1 kg was calculated, with 85% coming from vineyards and minor urban sources and 15% from arable crops. Small vineyard surfaces could generate high concentrations of herbicides and contribute considerably to the total load calculated at the outlet, due to their steep slopes (~10%). The extrapolated total amount transferred yearly from the Lavaux vineyards to the Lake of Geneva was of 190kg. At the molecular scale, the possible involvement of dissolved organic matter (DOM) in glyphosate and copper transport was studied using UV/Vis fluorescence spectroscopy. Combined with parallel factor (PARAFAC) analysis, this technique allowed characterizing DOM of soil and surface water samples from the studied vineyard area. Glyphosate concentrations were linked to the fulvic-like spectroscopic signature of DOM in soil water samples, as well as to copper, suggesting the formation of ternary complexes. In surface water samples, its concentrations were also correlated to copper ones, but not in a significant way to the fulvic-like signature. Quenching experiments with standards confirmed field tendencies in the laboratory, with a stronger decrease in fluorescence intensity for fulvic-like fluorophore than for more aromatic ones. Lastly, based on maximum concentrations measured in the river, an environmental risk for these compounds was assessed, using laboratory tests and ecotoxicity data from the literature. In our case and with the methodology applied, the risk towards aquatic species was found negligible (RF<1).

Valtatien 4 parantaminen Vaajakosken kohdalla, Jyväskylä : Yleissuunnitelma

Valtatie 4 on eräs Suomen tärkeimmistä päätieyhteyksistä. Vaajakosken kohdalla tien palvelutaso ja välityskyky on liikennemäärään nähden puutteellinen. Kiertoliittymät ja 50–60 km/h rajoitukset sijoittuvat kahden moottoritieosuuden väliin. Häiriötilanteessa lyhin kiertotie on yli 40 km pitkä. Nykytilanteessa valtatien 4 liikennemäärä suunnittelualueella on noin 17 000 – 21 000 ajon./vrk ja valtatien 9 liikennemäärä noin 10 300 ajon./vrk. Vuonna 2030 valtatien 4 liikennemäärän ennustetaan olevan 22 000 – 26 000 ajon./vrk ja valtatien 9 liikennemäärän 12 400 ajon./vrk. Suunnitteluosuudella valtatie 4 rakennetaan uuteen, Varassaaren kautta kulkevaan maastokäytävään. Rakennettavan osuuden pituus on noin 5 kilometriä. Nykyinen valtatie jää rinnakkaistieksi. Haapalahden nykyinen suuntaisliittymä parannetaan rakentamalla rampit Vaajakosken suuntaan. Kanavuoreen rakennetaan uusi eritasoliittymä. Valtatie 9 rakennetaan uuteen maastokäytävään noin 500 m matkalla. Nykyinen valtatie muuttuu kaduksi. Mustaniemeen rakennetaan uusi eritasoliittymä ennen Leppäveden vesistöpengertä. Uusia siltoja rakennetaan yhteensä 26. Kyseessä on ensisijaisesti sujuvuushanke. Valtatien 4 sujuvuus paraneekin huomattavasti, kun 85 % liikenteestä siirtyy uudelle tielinjalle. Myös paikallisen liikennöinnin sujuvuus ja turvallisuus paranevat. Liikenteen sujuvuuden parantamisen lisäksi hankkeella pyritään luomaan edellytyksiä Vaajakosken keskustan kehittämiselle. Uusi tielinjaus muuttaa maisemaa, mutta luo myös uusia maankäytön kehittämismahdollisuuksia. Valtatien varteen rakennetaan mittavat meluntorjuntarakenteet asuinrakennusten suojaamiseksi liikenteen melulta. Hankkeen kustannusarvio on 119,1 miljoonaa euroa (maku-ind. 157,4, 2000=100). Hankkeen hyöty–kustannus-suhde on 1,2. Suurimmat hyödyt muodostuvat aikakustannus- ja onnettomuuskustannussäästöistä. Hankkeen toteuttaminen vähentää henkilövahinkoon johtaneita onnettomuuksia laskennallisesti noin 35 %.

Chemical composition, acetylcholinesterase inhibitory and antifungal activities of Pera glabrata (Schott) Baill. (Euphorbiaceae)

Pera glabrata (Schott) Baill. was selected for this study after showing a preliminary positive result in a screening of Atlantic Forest plant species in the search for acetylcholinesterase inhibitors and antifungal compounds. The bioassays were conducted with crude ethanol extract of the leaves using direct bioautography method for acetylcholinesterase and antifungal activities. This extract was partitioned with hexane, chloroform and ethyl acetate solvents. The active chloroform fraction was submitted to silica gel chromatography column affording 12 groups. Caffeine, an alkaloid, which showed detection limits of 0.1 and 1.0 µg for anticholinesterasic and antifungal activities, respectively, was isolated from group nine. After microplate analyses, only groups four, nine, 10, 11 and 12 showed acetylcholinesterase inhibitory activity of 40% or higher. The group 12 was purified by preparative layer chromatography affording four sub-fractions. Two sub-fractions from this group were analyzed by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector. The first sub-fraction showed anticholinesterasic activity and contained two major compounds: 9-hydroxy-4-megastigmen-3-one (84%) and caffeine (6%). The second sub-fraction presented five major compounds identified as 9-hydroxy-4-megastigmen-3-one, isololiolide, (-) loliolide, palmitic acid and lupeol and did not show activity.

Recueil de lettres de P. de Marca, adressées, pendant son séjour en Catalogne, principalement à Michel Le Tellier. Du 4 janvier 1650 au 30 juillet 1651. Copies.

Contient : 1 à 8 Huit lettres de P. DE MARCA à M. Le Tellier. Des 4, 12, 17, 19, 28 janvier, 1er février 1650 ; 9 « Relation de ce qui a esté faict en execution du contenu aux instructions de S. M. [LOUIS XIV], du 18 janvier 1650, envoyées au Sr de Marca » ; 10 à 30 Vingt et une lettres de P. DE MARCA ; 10 à 22 à M. Le Tellier. Des 1, 4, 5, 9, 25, 26 février, 2, 6, 9, 15, 23, 30 mars 1650 ; 23 « à Mrde Brienne. Du 2 avril 1650 » ; 24 et 25 à M. Le Tellier. Des 20 et 29 avril 1650 » ; 26 au cardinal Mazarin. Du 29 avril 1650 ; 27 à 30 à M. Le Tellier. Des 3, 4, 18, 25 mai 1650 ; 31 Placet adressé au roi LOUIS XIV par la comtesse DE ÇAVALLA, touchant les droits de cette dame aux revenus de la baronnie de Belpuech ; 32 à 38 Sept lettres de P. DE MARCA ; 32 et 33 à M. Le Tellier. Du 1er juin 1650 ; 34 au « duc de Mercoeur. Le 28 may 1650 » ; 35 à 38 à M. Le Tellier. Des 8 et 12 juin, 6 juillet 1650 ; 39 « Relation de ce qui s'est passé à Barcelone contre les conjurez. Du 12 juillet 1650 » ; 40 et 41 Deux mémoires de P. DE MARCA ; 40 « sur les divisions de Catalogne, et du remede qui s'y peut apporter » ; 41 « touchant les biens confisquez. Du 5 juillet 1650 » ; 42 « Lettre de P. DE MARCA à M. Le Tellier. Du 13 juillet 1650 » ; 43 « Project de la declaration » du roi « LOUIS [XIV], pour la revocation des dons des biens confisquez en Catalogne » ; 44 à 51 Huit lettres de P. DE MARCA ; 44 à 48 à M. Le Tellier. Des 19 et 26 juillet, 2 et 16 août 1650 ; 49 au cardinal Mazarin. Du 16 août 1650 ; 50 et 51 à M. Le Tellier. Des 23 et 30 août 1650 ; 52 « Relation de la prise de Falset. Du 29 aoust 1650 » ; 53 « Memoire du 29 d'aoust 1650 », sur les affaires de Catalogne ; 54 à 59 Six lettres de P. DE MARCA à M. Le Tellier. Des 6, 13, 14 septembre 1650 ; 60 « Estat des affaires de Catalogne. Du 2 octobre 1650 » ; 61 à 74 Quatorze lettres de P. DE MARCA ; 61 et 62 à M. Le Tellier. Des 4 et 11 octobre 1650 ; 63 au cardinal Mazarin. Du 11 octobre 1650 ; 64 à 68 à M. Le Tellier. Des 16 et 18 octobre, 1er, 2 et 8 novembre 1650 ; 69 « à MrOndedei. Du 8 novembre 1650 » ; 70 à 74 à M. Le Tellier. Des 8, 15, 22 novembre 1650 ; 75 « Lettre de Mr DE CANILLAC à Mr de Marca. Du 11 novembre 1650 » ; 76 à 81 Six lettres de P. DE MARCA à M. Le Tellier. Des 24 et 29 novembre, 5, 6, 12, 13 décembre 1650 ; 82 « Memoire de Mr DE MARCA », sur les affaires de Catalogne. Du 17 décembre 1650 ; 83 Lettre de P. DE MARCA à M. Le Tellier. Du 22 décembre 1650 ; 84 « Memoire de Mrs DE ST MEGRIN, DE MARCA, DE MARGARIT et LECLERC, touchant l'estat de la Catalogne. Du 22 decembre 1650 » ; 85 à 97 Treize lettres de P. DE MARCA ; 85 « à MrOndedei. Le 22 decembre 1650 » ; 86 à 97 à M. Le Tellier. Des 26 decembre 1650, 3, 10, 14, 22, 24, 31 janvier, 4, 7 et 14 février 1651 ; 98 « Memoire de [P.] DE MARCA sur la conduitte de Mr l'evesque d'Orange » ; 99 Lettre de P. DE MARCA à M. Le Tellier. Du 21 février 1651 ; 100 « Relation de ce qui s'est passé en l'entreprise que les ennemis ont voulu faire sur Prades en Catalogne » ; 101 à 105 Cinq lettres de P. DE MARCA à M. Le Tellier. Des 28 février, 7, 14 mars 1651 ; 106 « Memoire du 14 mars 1651, sur la conduite de Mrs l'evesque d'Orange, comte d'Ille et regent Fontanella » ; 107 à 134 Vingt-huit lettres de P. DE MARCA à M. Le Tellier. Des 27 mars, 4, 12, 23 avril, 3, 6, 14 à 16, 21, 27, 31 mai, 7, 16 à 18, 21, 30 juin, 1, 10, 24, 30 juillet 1651

The Smiles rearrangement in hydrazidic systems and related syntheses /|nG. A. Pawelchak. -- 260 St. Catharines, Ont. : [s. n.],

This research was directed towards the investigation of the Smiles rearrangement in hydrazidic systems and the synthesis of related heterocyclic compounds. The work can be conveniently divided into two main sections. Section 1 of the thesis relates to the synthesis and examination of the O+N migration of phenoxy- derivatives of hydrazidic halides. In general, hydrazidic halides were found to react with 2-nitrophenol and 4-nitrophenol to give corresponding a-nitrophenoxy- compounds. These a-nitrophenoxy- compounds were found to rearrange in warm base to give the corresponding N-benzoyl compounds via a proposed five-membered transition state. Experiments conducted in styrene revealed no radical contribution to the rearrangement. Cross-over product analysis indicated the rearrangement as intramolecular and consistent with the Smiles rearrangement. The preparation of N-a-chlorobenzylidene-N'-2-nitrophenyl- -N'-(2,4-dibromophenyl)hydrazine from N-benzoyl-N'-2-nitrophenyl- N'-(2,4-dibromophenyl)hydrazine was accomplished using phosphorus oxychloride. Examination of this hydrazidic chloride indicated a marked decrease .in reactivity as compared to the N-a-chlorobenzylidene-N'-phenylhydrazine case. Section 2 concerns itself with the preparation of heterocyclic compounds using an analogy of the five-membered transition state present in the Smiles rearrangement of a substituted benzylidene derivatives A new preparation of 2,4-phenyl1,3,4- oxadiazol-S-one using N-benzoyl-N'-phenylhydrazine and ethyl thiochloroformate is reported. Two new preparations of N-a-thiobenzoyl-N'-(2,4-dibromophenylhydrazine are reported using sodium hydrosulfide in conjunction with N-a-bromobenzylidene-N'-(2,4-dibromophenyl)hydrazine in the first, and phosphorus pentasulfide with N-benzoylN'-( 2,4-dibromophenyl)hydrazine in the second. The latter is preferred due to the formation of a sulfide co-product in the former. Two preparations of 2-phenyl-4-(2,4-dibromophenyl)-1,3,4- thiadiazol-S-one are reported using N-thiobenzoyl-N'-(2,4-dibromophenyl) hydrazine and ethyl chloroformate and ethyl thiochloroformate Two rapid and easy preparations of 2-phenyl-4-(2,4-dibromophenyl)- 1,3,4-triazol-S-one are reported using ethyl chloroformate and ethyl thiochloroformate. Sodium cyanate in conjunction with a-aminobenzylidene-N'-(2,4-dibromophenyl)hydrazine also provided 2-phenyl-4-(2,4-dibromophenyl)-1,3,4-triazol-S-one Section 2 concludes with an examination of two possible mechanistic routes to the prepared heterocycles.

Detection of phenolic compounds using impedance spectroscopy measurements

Langmuir-Blodgett (LB) and layer-by-layer films (LbL) of a PPV (p-phenylenevinylene) derivative, an azo compound and tetrasulfonated phthalocyanines were successfully employed as transducers in an ""electronic tongue"" system for detecting trace levels of phenolic compounds in water. The choice of the materials was based on their distinct electrical natures, which enabled the array to establish a fingerprint of very similar liquids. Impedance spectroscopy measurements were taken in the frequency range from 10 Hz to 1 MHz, with the data analysed with principal component analysis (PCA). The sensing units were obtained from five-layer LB films of (poly[(2-methoxy-5-n-hexyloxy)-p-phenylenevinylene]), OC(1)OC(18)-PPV (poly(2-methoxy,5-(n-octadecyl)-p-phenylenevinylene)), DR (HEMA-co-DR13MA (poly-(hydroxyethylmethacrylate-co-[4`-[[2-(methacryloyloxy)-ethyl]ethylamino]-2-chloro-4-nitroazobenzene]))) and five-bilayer LbL films of tetrasulfonated metallic phthalocyanines deposited onto gold interdigitated electrodes. The sensors were immersed into phenol, 2-chloro-4-methoxyphenol, 2-chlorophenol and 3-chlorophenol (isomers) solutions at 1 x 10(-9) mol L(-1), with control experiments carried out in ultra pure water. Samples could be distinguished if the principal component analysis (PCA) plots were made with capacitance values taken at 10(3) Hz, which is promising for detection of trace amounts of phenolic pollutants in natural water.

Luminescent nanoparticles of MgAl(2)O(4):Eu, Dy prepared by citrate sol-gel method

MgAl(2)O(4):Eu, Dy nanoparticles were prepared by citrate sol-gel method and thermally treated at 600, 700, 800 and 900 degrees C. The trivalent europium ion is partially reduced to the divalent state at 700 and 800 degrees C. Infrared spectra of the phosphors showed bands around 700 and 520 cm(-1) corresponding to the AlO(6) groups. X-ray diffraction patterns present sharp reflections of samples heated from 700 to 900 degrees C indicating the MgAl(2)O(4) spinel phase. Grain size in the range 20-30 nm were observed by measurement of transmission electron microscopy (TEM). The emission spectra of the phosphors show a broadened band at 480 nm assigned to the 4f(G)5d -> 4f(7) ((8)S(7/2)) transition of Eu(2+) ion overlapped to the (4)F(9/2) -> (6)H(15/2) transition of the Dy(3+) ion. Besides, the (4)F(9/2) -> (6)H(13/2) transition (579 nm) of Dy(3+) ion is overlapped with the (5)D(0) -> (7)F(0) (578 nm) and (5)D(0) -> (7)F(1) (595 nm) transitions from the Eu(3+) ion. Excitation spectra of the sample heated at 900 degrees C monitoring the excitation at 615 nm of (5)D(0) -> (7)F(2) transition of Eu(3+) ion exhibit a broad band assigned to the O -> Eu(3+) ligand-to-metal charge-transfer states (LMCT) around 280 nm. The samples present green persistent luminescence after exposure to UV radiation. The chromaticity coordinates were obtained from the luminescence emission spectrum. (C) 2008 Elsevier B.V. All rights reserved.

Development of a dynamic headspace solid-phase microextraction procedure coupled to GC–qMSD for evaluation the chemical profile in alcoholic beverages

In the present study, a simple and sensitive methodology based on dynamic headspace solid-phase microextraction (HS-SPME) followed by thermal desorption gas chromatography with quadrupole mass detection (GC–qMSD), was developed and optimized for the determination of volatile (VOCs) and semi-volatile (SVOCs) compounds from different alcoholic beverages: wine, beer and whisky. Key experimental factors influencing the equilibrium of the VOCs and SVOCs between the sample and the SPME fibre, as the type of fibre coating, extraction time and temperature, sample stirring and ionic strength, were optimized. The performance of five commercially available SPME fibres was evaluated and compared, namely polydimethylsiloxane (PDMS, 100 μm); polyacrylate (PA, 85 μm); polydimethylsiloxane/divinylbenzene (PDMS/DVB, 65 μm); carboxen™/polydimethylsiloxane (CAR/PDMS, 75 μm) and the divinylbenzene/carboxen on polydimethylsiloxane (DVB/CAR/PDMS, 50/30 μm) (StableFlex). An objective comparison among different alcoholic beverages has been established in terms of qualitative and semi-quantitative differences on volatile and semi-volatile compounds. These compounds belong to several chemical families, including higher alcohols, ethyl esters, fatty acids, higher alcohol acetates, isoamyl esters, carbonyl compounds, furanic compounds, terpenoids, C13-norisoprenoids and volatile phenols. The optimized extraction conditions and GC–qMSD, lead to the successful identification of 44 compounds in white wines, 64 in beers and 104 in whiskys. Some of these compounds were found in all of the examined beverage samples. The main components of the HS-SPME found in white wines were ethyl octanoate (46.9%), ethyl decanoate (30.3%), ethyl 9-decenoate (10.7%), ethyl hexanoate (3.1%), and isoamyl octanoate (2.7%). As for beers, the major compounds were isoamyl alcohol (11.5%), ethyl octanoate (9.1%), isoamyl acetate (8.2%), 2-ethyl-1-hexanol (5.9%), and octanoic acid (5.5%). Ethyl decanoate (58.0%), ethyl octanoate (15.1%), ethyl dodecanoate (13.9%) followed by 3-methyl-1-butanol (1.8%) and isoamyl acetate (1.4%) were found to be the major VOCs in whisky samples.

Detection of phenolic compounds using impedance spectroscopy measurements

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of ionic interactions on the photoinduced Birefringence of poly[1-[4-(3-carboxy-4 hydroxyphenylazo) benzene sulfonamido]-1 2-ethanediyl, sodium salt] films

Electrostatic interactions govern most properties of polyelectrolyte films, as in the photoinduced bire-fringence of azo-containing polymers. In this paper we report a systematic investigation of optical storage characteristics of cast and layer-by-layer (LbL) films of poly[1 -[4-(3-carboxy-4 hydroxypheny-lazo) benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO). Birefringence was photoinduced faster in PAZO cast films prepared at high pHs, with the characteristic writing times decreasing almost linearly with the pH in the range between 4 and 9. This was attributed to an increased free volume for the azochromophores with the enhanced electrostatic repulsion in PAZO charged to a greater extent. In contrast, in LbL films of PAZO alternated with poly(allylamine hydrochloride) (PAH), the electrostatic interactions between the oppositely charged polymers hampered photoisomerization and molecular rearrangement, thus leading to a slower writing kinetics for highly charged PAH or PAZO.

Application of a Biomimetic Sensor Based on Iron Phthalocyanine Chloride: 4-Methylbenzylidene-Camphor Detection

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Electro-precipitation of Fe(3)O(4) nanoparticles in ethanol

The preparation of superparamagnetic magnetite (Fe(3)O(4)) nanoparticles by electro-precipitation in ethanol is proposed. Particle average size can be set from 4.4 to 9 nm with a standard deviation around 20%. Combination of wide-angle X-ray scattering (WAXS), Electron energy loss spectroscopy (EELS) and Mossbauer spectroscopy characterizations clearly identifies the particles as magnetite single-crystals (Fe(3)O(4)). (C) 2008 Elsevier B.V. All rights reserved.