Questo lavoro è stato finanziato da SONATA, un progetto congiunto tra la francese Agence Nationale de la Recherche (ANR-13-IS08-0001) e la National Science Foundation degli Stati Uniti. Christine Baduel è finanziato dall&#39;Agenzia nazionale francese di ricerca (ANR) attraverso il progetto ANR-16-ACHN-0026. Gli autori hanno anche calorosamente ringraziare Marija Marguš, Ana Cvitesic, Sanja Frka Milosavljević e Irena Ciglenecki, dal Rudjer Boskovic Institute di Zagabria, in Croazia per l&#39;aiuto con il campionamento di aerosol a Marina Frapa, Rogoznica, Croazia.

<ol>
	<li>K&#246;hler, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+nucleus+in+and+the+growth+of+hygroscopic+droplets.">The nucleus in and the growth of hygroscopic droplets.</a> Trans. Faraday Soc. 32, 1152-1161 (1936).</li><li>Noziere, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CLOUDS.+Don't+forget+the+surface.">CLOUDS. Don't forget the surface.</a> Science. 351, 1396-1397 (2016).</li><li>Onaizi, S. A., Nasser, M. S., Twaiq, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adsorption+and+thermodynamics+of+biosurfactant,+surfactin,+monolayers+at+the+air-buffered+liquid+interface.">Adsorption and thermodynamics of biosurfactant, surfactin, monolayers at the air-buffered liquid interface.</a> Colloid Polym Sci. 292, 1649-1656 (2014).</li><li>Ekstr&#246;m, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+possible+role+of+ground-based+microorganisms+on+cloud+formation+in+the+atmosphere.">A possible role of ground-based microorganisms on cloud formation in the atmosphere.</a> Biogeosci. 7, 387-394 (2010).</li><li>Baduel, C., Nozi&#232;re, B., Jaffrezo, J. -. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Summer/winter+variability+of+the+surfactants+in+aerosols+from+Grenoble,+France.">Summer/winter variability of the surfactants in aerosols from Grenoble, France.</a> Atmos. Environ. 47, 413-420 (2012).</li><li>G&#233;rard, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anionic,+Cationic,+and+Nonionic+Surfactants+in+Atmospheric+Aerosols+from+the+Baltic+Coast+at+Ask&#246;,+Sweden:+Implications+for+Cloud+Droplet+Activation.">Anionic, Cationic, and Nonionic Surfactants in Atmospheric Aerosols from the Baltic Coast at Ask&#246;, Sweden: Implications for Cloud Droplet Activation.</a> Environ. Sci. Technol. 50, 2974-2982 (2016).</li><li>Renard, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Screening+of+cloud+microorganisms+isolated+at+the+Puy+de+Dôme+(France)+station+for+the+production+of+biosurfactants.">Screening of cloud microorganisms isolated at the Puy de Dôme (France) station for the production of biosurfactants.</a> Atmos Chem Phys. 16, 12347-12358 (2016).</li><li>Nozi&#232;re, B., Baduel, C., Jaffrezo, J. -. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+dynamic+surface+tension+of+atmospheric+aerosol+surfactants+reveals+new+aspects+of+cloud+activation.">The dynamic surface tension of atmospheric aerosol surfactants reveals new aspects of cloud activation.</a> Nature Comm. 5, 4335 (2014).</li><li>Ruehl, C. R., Davies, J. F., Wilson, K. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+interfacial+mechanism+for+cloud+droplet+formation+on+organic+aerosols.">An interfacial mechanism for cloud droplet formation on organic aerosols.</a> Science. 351, 1447-1450 (2016).</li><li>Jimenez, J. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evolution+of+Organic+Aerosols+in+the+Atmosphere.">Evolution of Organic Aerosols in the Atmosphere.</a> Science. 326, 1525-1529 (2009).</li><li>Latif, M. T., Brimblecombe, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surfactants+in+Atmospheric+Aerosols.">Surfactants in Atmospheric Aerosols.</a> Environ. Sci. Technol. 38, 6501-6506 (2004).</li><li>Amirov, R. R., Skvortsova, E. A., Saprykova, Z. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Complexation+of+Cobalt(II)+with+Thiocyanate+Ions+in+Aqueous+Solutions+of+Nonionogenic+Surfactants.">Complexation of Cobalt(II) with Thiocyanate Ions in Aqueous Solutions of Nonionogenic Surfactants.</a> Russ. J. Coord. Chem. 29, 554-558 (2003).</li><li>Jaafar, S. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surfactants+in+the+sea-surface+microlayer+and+atmospheric+aerosol+around+the+southern+region+of+Peninsular+Malaysia.">Surfactants in the sea-surface microlayer and atmospheric aerosol around the southern region of Peninsular Malaysia.</a> Mar. Pollut. Bull. 84, 35-43 (2014).</li><li>Mustaffa, N., Latif, M., Ali, M., Khan, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Source+apportionment+of+surfactants+in+marine+aerosols+at+different+locations+along+the+Malacca+Straits.">Source apportionment of surfactants in marine aerosols at different locations along the Malacca Straits.</a> Environ Sci Pollut Res. 21, 6590-6602 (2014).</li><li>Motomizu, S., Fujiwara, S., Fujiwara, A., Toei, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solvent+extraction-spectrophotometric+determination+of+anionic+surfactants+with+ethyl+violet.">Solvent extraction-spectrophotometric determination of anionic surfactants with ethyl violet.</a> Anal. Chem. 54, 392-397 (1982).</li><li>Yamamoto, K., Motomizu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solvent+extraction-spectrophotometric+determination+of+anionic+surfactants+in+sea+water.">Solvent extraction-spectrophotometric determination of anionic surfactants in sea water.</a> Analyst. 112, 1405-1408 (1987).</li><li>Schmitt, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Analysis of Surfactants (Surfactant Science). 96, 421-443 (2001).</li><li>Hummel, D. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Handbook of Surfactant Analysis: Chemical, Physico-chemical and Physical Methods. , 203 (2000).</li><li>Pacheco e Silva, V., al, e. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+to+measure+surfactant+in+fluid.">Method to measure surfactant in fluid.</a> US patent. , (2013).</li><li>Bzdek, B. R., Power, R. M., Simpson, S. H., Reid, J. P., Royall, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Precise,+contactless+measurements+of+the+surface+tension+of+picolitre+aerosol+droplets.">Precise, contactless measurements of the surface tension of picolitre aerosol droplets.</a> Chem Sci. 7, 274-285 (2016).</li><li>Desai, J. D., Banat, I. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microbial+production+of+surfactants+and+their+commercial+potential.">Microbial production of surfactants and their commercial potential.</a> Microbiol. Mol. Biol. R. 61, 47-64 (1997).</li><li>Christofi, N., Ivshina, I. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microbial+surfactants+and+their+use+in+field+studies+of+soil+remediation.">Microbial surfactants and their use in field studies of soil remediation.</a> J. Appl. Microbiol. 93, 915-929 (2002).</li><li>Facchini, M. C., Mircea, M., Fuzzi, S., Charlson, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cloud+albedo+enhancement+by+surface-active+organic+solutes+in+growing+droplets.">Cloud albedo enhancement by surface-active organic solutes in growing droplets.</a> Nature. 401, 257-259 (1999).</li><li>Mircea, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Importance+of+the+organic+aerosol+fraction+for+modeling+aerosol+hygroscopic+growth+and+activation:+a+case+study+in+the+Amazon+Basin.">Importance of the organic aerosol fraction for modeling aerosol hygroscopic growth and activation: a case study in the Amazon Basin.</a> Atmos. Chem. Phys. 5, 3111-3126 (2005).</li><li>Varga, B., Kiss, G., Ganszky, I., Gelencs&#233;r, A., Kriv&#225;csy, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+water-soluble+organic+matter+from+atmospheric+aerosol.">Isolation of water-soluble organic matter from atmospheric aerosol.</a> Talanta. 55, 561-572 (2001).</li><li>Kiss, G., Tomb&#225;cz, E., Hansson, H. -. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+Tension+Effects+of+Humic-Like+Substances+in+the+Aqueous+Extract+of+Tropospheric+Fine+Aerosol.">Surface Tension Effects of Humic-Like Substances in the Aqueous Extract of Tropospheric Fine Aerosol.</a> J Atmos Chem. 50, 279-294 (2005).</li><li>Salma, I., Ocskay, R., Varga, I., Maenhaut, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+tension+of+atmospheric+humic-like+substances+in+connection+with+relaxation,+dilution,+and+solution+pH.">Surface tension of atmospheric humic-like substances in connection with relaxation, dilution, and solution pH.</a> J. Geophys. Res. 111, D23205 (2006).</li><li>Taraniuk, I., Graber, E. R., Kostinski, A., Rudich, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surfactant+properties+of+atmospheric+and+model+humic-like+substances+(HULIS).">Surfactant properties of atmospheric and model humic-like substances (HULIS).</a> Geophys. Res. Lett. 34, L16807 (2007).</li><li>Morris, H. S., Grassian, V. H., Tivanski, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Humidity-dependent+surface+tension+measurements+of+individual+inorganic+and+organic+submicrometre+liquid+particles.">Humidity-dependent surface tension measurements of individual inorganic and organic submicrometre liquid particles.</a> Chemical Science. 6, 3242-3247 (2015).</li><li>Roslan, R. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surfactants+in+the+sea-surface+microlayer+and+their+contribution+to+atmospheric+aerosols+around+coastal+areas+of+the+Malaysian+peninsula.">Surfactants in the sea-surface microlayer and their contribution to atmospheric aerosols around coastal areas of the Malaysian peninsula.</a> Mar. Pollut. Bull. 60, 1584-1590 (2010).</li><li>Orlovi&#263;-Leko, P., Kozarac, Z., &#262;osovi&#263;, B., Strme&#269;ki, S., Plav&#353;i&#263;, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+atmospheric+surfactants+in+the+bulk+precipitation+by+electrochemical+tools.">Characterization of atmospheric surfactants in the bulk precipitation by electrochemical tools.</a> J Atmos Chem. 66, 11-26 (2010).</li><li>Frka, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface-active+substances+in+atmospheric+aerosol:+an+electrochemical+approach.">Surface-active substances in atmospheric aerosol: an electrochemical approach.</a> Tellus B. 64, 12 (2012).</li></ol>

Gli autori non hanno nulla da rivelare.

Nel protocollo, sono state dettagliatamente tutti i passaggi critici. Essi comprendono la raccolta degli aerosol su filtri, l&#39;estrazione di tensioattivi da loro (usando una doppia estrazione: un&#39;estrazione di acqua seguita da un&#39;estrazione SPE) e l&#39;analisi degli estratti (tensione superficiale e misure di concentrazione). Per l&#39;intero metodo, un controllo di qualità è stato fatto 1) mediante l&#39;applicazione del metodo di estrazione e analisi su filtri vuoti (deviazione &lt;5 mN m -1 rispetto acqua ultrapura sulla tensione superficiale e l&#39;assorbanza di sotto del limite di rivelazione per la colorimetrico metodo), 2) determinando l&#39;efficienza di estrazione e loro incertezze compresa la riproducibilità / ripetibilità, la% di tensioattivi estratti in un dato intervallo di concentrazione, 3) controllando i potenziali interferenti sul metodo colorimetrico, cioè verificando che le rileva metodo solo il tipo mirato di tensioattivo (Anionic, cationici e non-ionici) e non vedono gli altri come estesamente descritto nei riferimenti 4, 6) controllando possibili interferenti da estratti di aerosol (sali inorganici, acidi piccoli) sul metodo colorimetrico come descritte in dettaglio in riferimento 6. A nostra conoscenza, il metodo di estrazione dei tensioattivi da campioni atmosferici presentati in questo articolo è attualmente il più selettivo nella chimica atmosferica. In particolare è molto più selettivo rispetto alle semplici estrazioni acqua effettuati in passato per la ricerca di questi composti. 11, 23, 24 La seconda fase di estrazione è importante in quanto è stato dimostrato per rimuovere componenti ionici, come sali inorganici e piccole acidi organici, che sono grandi concentrazioni nei campioni di aerosol e interferiscono con la concentrazione measurements. 6 Questo metodo di estrazione è stato anche dimostrato per rimuovere tutti i tensioattivi presenti nei campioni, in superficie che in massa. Gli estratti risultanti sono quindi concentrati a sufficienza per consentire caratterizzazioni accurate di questi composti. Tuttavia, oltre ai tensioattivi, è possibile che altri composti non polari o mediamente polari vengono estratti dai aerosol atmosferici. Ad esempio, &quot;sostanze umiche-like&quot; (HULIS), che di solito sono estratti mediante metodi simili 25 e, a seconda della regione di campionamento, potrebbero essere presenti negli estratti. Questi composti sono solo lievemente tensioattivo rispetto ai tensioattivi caratterizzato nostri campioni, 26, 27, 28 quindi non dovrebbe contribuire in maniera significativa alla tensione superficiale o CMC misurata. Tuttavia, essi sono poliacidi e potrebbero interferire con la conce anionico<html> Misure ntration. In futuro, il loro contributo alle concentrazioni di tensioattivo (cioè se o non reagiscono con violetto di etile, il colorante impiegato per titolare tensioattivi anionici) dovrà essere determinata. Se il loro contributo è significativo, passaggi aggiuntivi possono essere aggiunti al metodo di estrazione, per eliminare per esempio tutti i composti che sono attive nel UV-Vis o per fluorescenza, che includono tensioattivi HULIS ma non. Finora, nessun altro metodo per la misurazione della tensione superficiale di aerosol e della curva di tensione superficiale dei tensioattivi aerosol di quello presentato in questo manoscritto è disponibile. La tecnica goccia che incombe è raccomandato per tali misurazioni è l&#39;unico che richiede volumi di campione coerenti con campioni atmosferici. tecniche ottiche, misurando direttamente la tensione superficiale sulle particelle micron di dimensioni senza estrazione, si stanno sviluppando. 10,ass = &quot;xref&quot;&gt; 20, 29 Finora, sono applicabili solo alle particelle prodotte in laboratorio ma potrebbe potenzialmente giorno essere applicato a quelli atmosferici. Il metodo colorimetrico presentata in questo lavoro per la misura della concentrazione di tensioattivo è stata applicata in precedenza per campioni di aerosol atmosferici 11, 13, 14, 30 ma solo a estratti acquosi e non raddoppiare estratti, come nel nostro metodo. Questa è una differenza importante, come sottolineato in precedenza, la seconda fase di estrazione rimuove composti come sali inorganici e piccole acidi organici, che interferiscono con le misure di concentrazione. 6 Una tecnica elettrochimica, inizialmente sviluppato per acqua di mare e campioni acquosi grandi, è stato utilizzato anche per misurare la concentrazione di tensioattivi in ​​atmosaerosol dità. 31, 32 Questo metodo è relativo, cioè le concentrazioni di tensioattivo ottenuti dipendono dai composti di riferimento scelti e presuppongono che la sensibilità di rilevazione di tutti i tensioattivi è identico. Il limite di rilevamento indicato per questa tecnica è di 0,02 mg L -1 utilizzando tetra-octylphenolethoxylate come riferimento, così 0,03 pM, e paragonabile al limite di rilevamento di circa 0,05 pM di tensioattivi anionici e cationici con il metodo colorimetrico. Ma a causa delle incertezze nella determinazione delle concentrazioni di tensioattivi non ionici e totali con il metodo colorimetrico, sarebbe interessante confrontare entrambi i metodi (inter-calibrazione). Alcuni punti nei metodi presentati potrebbero essere ulteriormente migliorati. Un altro colorante rispetto al cobalto tiocianato che rilevare tutti i tensioattivi non ionici e spirito la stessa sensibilità sarebbe molto USEFul e ridurre la principale fonte di incertezze nelle misure di concentrazione in corso. L&#39;efficienza di estrazione di tensioattivi cationici, attualmente stimato al 20%, potrebbe anche essere migliorata, in quanto questi composti sono spesso al limite di rilevamento in campioni atmosferici. Ciò potrebbe essere fatto, per esempio, utilizzando una colonna specifica SPE. Le estrazioni e condizioni titolazione potrebbe essere ulteriormente migliorata. Ad esempio, utilizzando in parallelo tre diversi SPE set-up, ciascuno ottimizzato per una classe di tensioattivi, potrebbe migliorare l&#39;efficienza di estrazione, e migliorare la qualità della procedura (meno rischi di contaminazione). La densità ottimale sorbente della cartuccia SPE per la massa del campione da analizzare potrebbe stato anche determinato. Le condizioni per le reazioni di titolazione (pH, additivi) potrebbero essere ulteriormente migliorate, per migliorare ulteriormente la sensibilità delle misure della concentrazione, ovvero abbassare i limiti di rilevazione. <p class =&gt; prove o fasi aggiuntive &quot;jove_content&quot; potrebbero essere aggiunti al protocollo di estrazione per escludere i composti non tensioattivi che potrebbero essere stati estratti. Ad esempio, la potenziale presenza di HULIS nei campioni poteva essere analizzata mediante tecniche ottiche (UV-Vis o fluorescenza). Ulteriori modifiche, senza migliorare la qualità dell&#39;analisi stessa, porterebbe maggiori informazioni tensioattivi atmosferici, come l&#39;applicazione del presente metodo di differenti dimensioni-frazioni (ossia sub-popolazioni) dell&#39;aerosol piuttosto che su tutte le particelle raccolte, come qui presentata. Altri tipi di analisi potrebbero anche essere applicati agli estratti come, LC / MS HR, MS tandem, o NMR per determinare la struttura chimica dei tensioattivi o UV-Vis assorbanza, fluorescenza o polarimetria, per indicare la presenza di highly- composti coniugati o chirali negli estratti.

Le nuvole sono essenziali per l&#39;atmosfera terrestre, per l&#39;idrologia della maggior parte degli ambienti ed ecosistemi, e per il sistema climatico. Ma alcuni aspetti dei loro meccanismi di formazione non sono ancora comprese, in particolare i contributi dei composti chimici presenti nelle particelle di aerosol che fungono da nuclei di condensazione. Teoria 1 prevede che i composti tensioattivi, o tensioattivi, presenti nelle particelle di aerosol dovrebbero migliorare fortemente la formazione di goccioline nube abbassando la tensione superficiale, così la loro energia di formazione. Ma questi effetti sono rimasti inafferrabile all&#39;osservazione per decenni e il ruolo dei tensioattivi sulla formazione delle nuvole è al momento negata da una grande parte della comunità atmosferico e ignorato in tutte le indagini cloud e modelli atmosferici e climatici. Una ragione per la mancanza di comprensione del ruolo dei tensioattivi aerosol in nube formazione è stata l&#39;assenza di metodo di isoin ritardo e li caratterizzano. A differenza di campioni provenienti da altri ambienti, l&#39;analisi di campioni atmosferici affronta sfide ricorrenti 2 come molto piccolo volume di campione e la massa (qui, tipicamente tra 10 e 100 mg) e la complessità chimica (miscele di sali minerali, e numerose sostanze organiche). Per superare queste difficoltà e migliorare la comprensione di aerosol tensioattivi alcuni metodi sono stati recentemente sviluppato dal nostro gruppo a 1) estrarre specifico questi composti da campioni di aerosol atmosferici, 2) determinare le loro concentrazioni assolute nella fase aerosol e 3) determinare le loro curve di tensione superficiale in acqua, compresa la loro micellare critica concentrazione (CMC), la concentrazione alla quale i tensioattivi sono saturi in superficie e iniziano a formare micelle in massa. Le ultime versioni di questi metodi sono presentati in questo documento. Ulteriori miglioramenti e altri tipi di caratterizzazioni, che potrebbero essere utilizzati in complement a quelli presentati, saranno discussi. Recenti applicazioni di questi metodi hanno già mostrato come tali analisi possono migliorare la comprensione del ruolo dei tensioattivi in formazione nuvola, evidenziando questo ruolo stesso, 3 determinare le concentrazioni di tensioattivo in aerosol atmosferici 3, 4, 5, 6 e modalità di azione nube formazione di goccioline, 3, 6 evidenziando la loro origine biogenica, 3, 4, 7 e spiegando loro mancanza di osservazione da strumenti classici. 8, 9, 10

<table border="0" cellpadding="0" cellspacing="0" width="1448">
	<tbody>
		<tr height="24">
			<td height="24" style="height:24px;width:828px;">Quartz filters</td>
			<td style="width:219px;">Fioroni</td>
			<td style="width:235px;"></td>
			<td style="width:167px;">for example &#216;47mm or &#216;150mm, Grammage 85g/m2</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Aluminium foils or glass Petri dishes</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td>backed in oven (773 K, 6h)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Tweezers, scissors</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Desiccator</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">SPE (Solid Phase Extraction) set-up</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">SPE vacuum manifold Ac-Elut</td>
			<td style="width:219px;">Varian&#160;</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Pump Laboxat</td>
			<td style="width:219px;">Knf LAB</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Nitrogen dryer set-up</td>
			<td style="width:219px;">hand-made</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Compressed Nirogen 4.5 in bottle B50, 200 bar at 15&#176;C</td>
			<td style="width:219px;">Linde</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Tensiometer</td>
			<td>Dataphysics&#160;</td>
			<td style="width:235px;">&#160;OCA 15EC</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:828px;">Software</td>
			<td style="width:219px;"></td>
			<td style="width:235px;">SCA software for OCA version 4-4.1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">UV-Vis spectrometer</td>
			<td>Agilent</td>
			<td style="width:235px;">8453</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Stir-plates</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Glassware</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Glass Petri dishes</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td>for the water extraction step</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Beakers</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">15 mL, 30 mL, 60 mL glass bottles with corks</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Tubes for SPE</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Magnetic stirring bars</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Ultrasound bath</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td>for glassware washing</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Micropipettes (0.5 - 5 mL, 0.100 - 1mL, 10 - 100 &#956;L)</td>
			<td style="width:219px;">Rainin Pipette-Life XLS</td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Disposable small&#160; equipment</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Syringe filters 0.40&#956;m PVDF</td>
			<td>Fisherbrand</td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">SPE C18 cartridges Strata C18-E cartridges 500 mg / 3 mL&#160;</td>
			<td style="width:219px;">Phenomenex</td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Plastic syringes</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Needles</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">4 mL-vials</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Pasteur glass pipettes</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Micropipette tips</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:828px;">Chemicals</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium dodecyl sulfate (SDS) &#8805; 98.5 % Bioreagent</td>
			<td>Sigma- Aldrich</td>
			<td style="width:235px;">L3771</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dioctyl sulfosuccinate sodium salt (AOT) &#8805; 97%</td>
			<td>Sigma- Aldrich</td>
			<td style="width:235px;">323586</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Benzyltetradecyldimethylammonium (zephiramine)&#160; &#8805; 99.0 % anhydrous Fluka</td>
			<td>Sigma- Aldrich</td>
			<td style="width:235px;">13401</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cetyltrimethylammonium chloride solution (CTAC) 25 wt % in H2O</td>
			<td>Sigma- Aldrich</td>
			<td style="width:235px;">292737</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol (Triton X114) laboratory grade</td>
			<td>Sigma- Aldrich</td>
			<td style="width:235px;">X114</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Polyethylene glycol dodecyl ether (Brij35) Fluka Bio Chemika</td>
			<td>Sigma- Aldrich</td>
			<td style="width:235px;">858366</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">L-&#945;-phosphatidylcholine from egg yolk type XVI-E&#160; lyophilized powder &#8805; 99 %</td>
			<td>Sigma- Aldrich</td>
			<td style="width:235px;">P3556</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Surfactin from Bacillus subtilis &#8805; 98 %</td>
			<td>Sigma- Aldrich</td>
			<td style="width:235px;">S3523</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">R-95Dd rhamnolipid (95 % dirhamnolipid, 5 % monorhamnolipid)&#160;</td>
			<td>Sigma- Aldrich</td>
			<td style="width:235px;">L510025</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ethyl violet cationic triarylmethane dye</td>
			<td>Sigma- Aldrich</td>
			<td style="width:235px;">228842</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Patent Blue VF dye content 50 %</td>
			<td>Sigma-Aldrich</td>
			<td style="width:235px;">198218</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ammonium thiocyanate &#8805; 99 % puriss. p.a.,&#160; ACS reagent</td>
			<td>Sigma-Aldrich</td>
			<td style="width:235px;">31120</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cobalt(II) nitrate hexahydrate &#8805; 98 % ACS reagent</td>
			<td>Sigma-Aldrich</td>
			<td style="width:235px;">239267</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Acetic anhydride &#8805; 99 % ReagentPlus</td>
			<td>Sigma-Aldrich</td>
			<td style="width:235px;">320102</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium acetate &#8805; 99.0 % anhydrous Reagent Plus</td>
			<td>Sigma-Aldrich</td>
			<td style="width:235px;">S8750</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ethylenediaminetetraacetic acid 99.4&#8722; 100.6 % ACS reagent powder</td>
			<td>Sigma-Aldrich</td>
			<td style="width:235px;">E9884</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium sulfate anhydrous &#8805; 99.0 % granulated puriss. p.a. ACS reagent Fluka</td>
			<td>Sigma-Aldrich</td>
			<td style="width:235px;">71960</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ethanol puriss. p.a. ACS Reagent&#160; reag. Ph. Eur. 96% (v/v)</td>
			<td>Sigma-Aldrich</td>
			<td style="width:235px;">32294</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Acetonitrile&#160; &#8805; 99.9 % HiPerSolv CHROMANORM Reag. Ph. Eur. (European Pharmacopoeia Reagent) grade gradient for HPLC</td>
			<td>VWR BDH Prolabo</td>
			<td>20060.32</td>
			<td style="width:167px;">to be manipulated under hood</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Chloroform 99 % stable with 0.8&#8722;1 % ethanol</td>
			<td>Alfa Aesar</td>
			<td style="width:235px;">L13200-0F</td>
			<td style="width:167px;">to be manipulated under hood</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Toluene &#62; 99 %</td>
			<td>Chimie Plus</td>
			<td style="width:235px;">24053</td>
			<td style="width:167px;">to be manipulated under hood</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Denatured ethanol for washing</td>
			<td style="width:219px;"></td>
			<td style="width:235px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:828px;">Ultra-Pure water</td>
			<td style="width:219px;">Ultrapure water system Purelab Classic, Elga</td>
			<td style="width:235px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

extraction and characterization of surfactants from atmospheric aerosols

composti tensioattivi, o tensioattivi, presenti negli aerosol atmosferici sono destinati a svolgere un ruolo importante nella formazione delle nubi acqua liquida nell&#39;atmosfera terrestre, un processo centrale in meteorologia, idrologia, e per il sistema di climatizzazione. Ma a causa di estrazione specifica e la caratterizzazione di questi composti sono mancati per decenni, molto poco si sa sulla loro identità, le qualità, la modalità di azione e origini, impedendo così la piena comprensione della formazione delle nuvole e dei suoi potenziali legami con gli ecosistemi della Terra. In questo articolo presentiamo recentemente sviluppati metodi per 1) estrazione mirata di tutti i tensioattivi da campioni di aerosol atmosferici e per la determinazione del 2) le concentrazioni assolute nella fase aerosol e 3) le curve di tensione superficiale statica in acqua, compresa la loro Critical micelle Concentrazione (CMC). Questi metodi sono stati convalidati con 9 riferimenti tensioattivi, ianionico ncluding, cationici e quelli non ionici. Esempi di risultati sono presentati per i tensioattivi presenti nelle particelle di aerosol fini (diametro &lt;1 micron) raccolti in un sito costiero in Croazia e suggerimenti per futuri miglioramenti e le altre caratterizzazioni di quelle presentate sono discussi.

Nota: Prima di essere applicata a campioni atmosferici, tutti i protocolli presentati in questa sezione sono stati testati con 9 tensioattivi di riferimento e le curve di tensione superficiale, tensioni minime superficiali, e CMC ottenuti erano in eccellente accordo con la letteratura. 21, 22 1. concentrazioni aerosol fini (&lt;1 micron di diametro, o &quot;PM1&quot;) i campioni sono stati raccolti su filtri in fibra di quarzo al sito costiero di Rogoznica, Croazia febbraio 2015. Questi campioni sono stati trattati ed estratti come descritto nelle sezioni 2 e 3, rispettivamente, di questo manoscritto. Le concentrazioni di tensioattivi anionici, cationici e tensioattivi non ionici e la concentrazione totale di tensioattivo nel volume del campione aerosol, C Surf, p (M), sono stati misurati secondo la sezione 4. Tha risultati sono presentati in Figura 1, e le prove la dominanza di tensioattivi anionici e non ionici tra i tensioattivi misurati. 2. tensione superficiale del campione e la tensione superficiale della curva a estratti Tensioattivi Combinando le misurazioni di tensione superficiale, come descritto nella Sezione 5, e le misure di concentrazione, determinato curve di tensione superficiale assoluti per gli stessi campioni, come mostrato in figura 2. Queste curve indicano la concentrazione di tensioattivo nel campione aerosol e la tensione superficiale di questi campioni ( &quot;σ min&quot;) e permettono di determinare graficamente i valori CMC (Figura 2). <img alt="Figura 1" class="xfigimg" src="/files/ftp_upload/55622/55622fig1.jpg" /> figura1: le concentrazioni di tensioattivo in aerosol sottili (PM1) raccolti in Rogoznica, Croazia. Concentrazioni per anionico (in blu), cationico (in rosso), tensioattivi non ionici (in verde) e la concentrazione totale di tensioattivo nella fase aerosol (somma di ogni concentrazioni di tensioattivi), Surf C, p (M), misurata con il colorimetrico procedimento fini (&lt;1 um) aerosol atmosferici raccolti nel sito costiera di Rogoznica, Croazia febbraio 2015. I risultati mostrano chiaramente la dominanza di tensioattivi anionici e tensioattivi non ionici. <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55622/55622fig1large.jpg" target="_blank">Si prega di cliccare qui per vedere una versione più grande di questa figura.</a> <img alt="figura 2" class="xfigimg" src="/files/ftp_upload/55622/55622fig2.jpg" /> Figura 2: Curva tensione superficiale tipica e CMC per i tensioattivi in aerosol daRogoznica, Croazia. curva tensione superficiale assoluto ai tensioattivi nel campione di 2015/03/02 ottenute combinando le misure di tensione e concentrazione superficiale. I punti neri rappresentano la tensione superficiale misurata dell&#39;estratto tensioattivo. Il punto arancione alla fine delle curve rappresenta la concentrazione calcolata nel campione aerosol (fase 4.4.6), e la sua tensione superficiale &quot;σ min&quot;. La determinazione grafica della CMC è illustrata. <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55622/55622fig2large.jpg" target="_blank">Si prega di cliccare qui per vedere una versione più grande di questa figura.</a>

Watch this Scientific Journal Video about Extraction and Characterization of Surfactants from Atmospheric Aerosols at JoVE.com

Extraction and Characterization of Surfactants from Atmospheric Aerosols

I metodi sono presentati per l&#39;estrazione mirata dei tensioattivi presenti negli aerosol atmosferici e la determinazione delle loro concentrazioni assolute e curve di tensione superficiale in acqua, compresa la loro concentrazione micellare critica (CMC).

Estrazione e caratterizzazione di tensioattivi da Atmospheric Aerosol

Surface-active compounds, or surfactants, present in atmospheric aerosols are expected to play important roles in the formation of liquid water clouds in ...

extraction-characterization-surfactants-from-atmospheric

Nanyang Technological University

Research

JoVE Journal

Environment

16.7K Views.  IRCELYON, F-69626.  I metodi sono presentati per l'estrazione mirata dei tensioattivi presenti negli aerosol atmosferici e la determinazione delle loro concentrazioni assolute e curve di tensione superficiale in acqua, compresa la loro concentrazione micellare critica (CMC). 

Video: Extraction and Characterization of Surfactants from Atmospheric Aerosols

Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study evaporation under various surface boundary conditions to improve our current understanding and characterization of this multiphase phenomenon as well as to validate numerical heat and mass transfer theories that couple Navier-Stokes flow in the atmosphere and Darcian flow in the porous media. Experimental data were collected using a unique soil tank apparatus interfaced with a small climate controlled wind tunnel. The experimental apparatus was instrumented with a suite of state of the art sensor technologies for the continuous and autonomous collection of soil moisture, soil thermal properties, soil and air temperature, relative humidity, and wind speed. This experimental apparatus can be used to generate data under well controlled boundary conditions, allowing for better control and gathering of accurate data at scales of interest not feasible in the field. Induced airflow at several distinct wind speeds over the soil surface resulted in unique behavior of heat and mass transfer during the different evaporative stages.

A protocol for the design and construction of a soil tank interfaced to a small climate controlled wind tunnel to study the effects of atmospheric forcings on evaporation is presented. Both the soil tank and wind tunnel are instrumented with sensor technologies for the continuous in situ measurement of environmental conditions.

Esplorare gli effetti dell&#39;inquinamento atmosferico forcing per evaporazione: Integrazione sperimentale dello strato atmosferica Boundary e Subsurface Shallow

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study ...

Ricerca

Ambiente

Simultaneous DNA-RNA Extraction from Coastal Sediments and Quantification of 16S rRNA Genes and Transcripts by Real-time PCR

Real Time Polymerase Chain Reaction also known as quantitative PCR (q-PCR) is a widely used tool in microbial ecology to quantify gene abundances of taxonomic and functional groups in environmental samples. Used in combination with a reverse transcriptase reaction (RT-q-PCR), it can also be employed to quantify gene transcripts. q-PCR makes use of highly sensitive fluorescent detection chemistries that allow quantification of PCR amplicons during the exponential phase of the reaction. Therefore, the biases associated with &#39;end-point&#39; PCR detected in the plateau phase of the PCR reaction are avoided. A protocol to quantify bacterial 16S rRNA genes and transcripts from coastal sediments via real-time PCR is provided. First, a method for the co-extraction of DNA and RNA from coastal sediments, including the additional steps required for the preparation of DNA-free RNA, is outlined. Second, a step-by-step guide for the quantification of 16S rRNA genes and transcripts from the extracted nucleic acids via q-PCR and RT-q-PCR is outlined. This includes details for the construction of DNA and RNA standard curves. Key considerations for the use of RT-q-PCR assays in microbial ecology are included.

A protocol to quantify bacterial 16S rRNA genes and transcripts from coastal sediments via real-time PCR is provided. The methodology includes the co-extraction of DNA and RNA; preparation of DNA-free RNA; and 16S rRNA gene and transcript quantification via RT-q-PCR, including standard curve construction.

DNA-RNA simultanea Estrazione da sedimenti costieri e la quantificazione dei geni 16S rRNA e trascrizioni da Real-time PCR

Real Time Polymerase Chain Reaction also known as quantitative PCR (q-PCR) is a widely used tool in microbial ecology to quantify gene abundances of ...

Laboratory Simulation of an Iron(II)-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling from hydrothermal sources in the Precambrian ocean was oxidized by molecular oxygen [O2] produced by cyanobacteria. The oldest BIFs, deposited prior to the Great Oxidation Event (GOE) at about 2.4 billion years (Gy) ago, could have formed by direct oxidation of Fe(II) by anoxygenic photoferrotrophs under anoxic conditions. As a method for testing the geochemical and mineralogical patterns that develop under different biological scenarios, we designed a 40 cm long vertical flow-through column to simulate an anoxic Fe(II)-rich marine upwelling system representative of an ancient ocean on a lab scale. The cylinder was packed with a porous glass bead matrix to stabilize the geochemical gradients, and liquid samples for iron quantification could be taken throughout the water column. Dissolved oxygen was detected non-invasively via optodes from the outside. Results from biotic experiments that involved upwelling fluxes of Fe(II) from the bottom, a distinct light gradient from top, and cyanobacteria present in the water column, show clear evidence for the formation of Fe(III) mineral precipitates and development of a chemocline between Fe(II) and O2. This column allows us to test hypotheses for the formation of the BIFs by culturing cyanobacteria (and in the future photoferrotrophs) under simulated marine Precambrian conditions. Furthermore we hypothesize that our column concept allows for the simulation of various chemical and physical environments &#8212; including shallow marine or lacustrine sediments.

Laboratory Simulation of an IronII-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria

We simulated a Precambrian ferruginous marine upwelling system in a lab-scale vertical flow-through column. The goal was to understand how geochemical profiles of O2 and Fe(II) evolve as cyanobacteria produce O2. The results show the establishment of a chemocline due to Fe(II) oxidation by photosynthetically produced O2.

Simulazione Laboratorio di ferro (II) ricchi di Precambriano Marine Upwelling sistema per esplorare la crescita di batteri fotosintetici

A conventional concept for the deposition of some Precambrian Banded Iron Formations (BIF) proceeds on the assumption that ferrous iron [Fe(II)] upwelling ...

Extraction of Structural Extracellular Polymeric Substances from Aerobic Granular Sludge

To evaluate and develop methodologies for the extraction of gel-forming extracellular polymeric substances (EPS), EPS from aerobic granular sludge (AGS) was extracted using six different methods (centrifugation, sonication, ethylenediaminetetraacetic acid (EDTA), formamide with sodium hydroxide (NaOH), formaldehyde with NaOH and sodium carbonate (Na2CO3) with heat and constant mixing). AGS was collected from a pilot wastewater treatment reactor. The ionic gel-forming property of the extracted EPS of the six different extraction methods was tested with calcium ions (Ca2+). From the six extraction methods used, only the Na2CO3 extraction could solubilize the hydrogel matrix of AGS. The alginate-like extracellular polymers (ALE) recovered with this method formed ionic gel beads with Ca2+. The Ca2+-ALE beads were stable in EDTA, formamide with NaOH and formaldehyde with NaOH, indicating that ALE are one part of the structural polymers in EPS. It is recommended to use an extraction method that combines physical and chemical treatment to solubilize AGS and extract structural EPS.

The protocol provides a methodology to solubilize aerobic granular sludge in order to extract alginate-like extracellular polymers (ALE).

Estrazione di sostanze strutturale extracellulare polimerici da aerobico granulare fanghi

To evaluate and develop methodologies for the extraction of gel-forming extracellular polymeric substances (EPS), EPS from aerobic granular sludge (AGS) ...

Biofilm Removal Using Carbon Dioxide Aerosols without Nitrogen Purge

Biofilms can cause serious concerns in many applications. Not only can they cause economic losses, but they can also present a public health hazard. Therefore, it is highly desirable to remove biofilms from surfaces. Many studies on CO2 aerosol cleaning have employed nitrogen purges to increase biofilm removal efficiency by reducing the moisture condensation generated during the cleaning. However, in this study, periodic jets of CO2 aerosols without nitrogen purges were used to remove Pseudomonas putida biofilms from polished stainless steel surfaces. CO2 aerosols are mixtures of solid and gaseous CO2 and are generated when high-pressure CO2 gas is adiabatically expanded through a nozzle. These high-speed aerosols were applied to a biofilm that had been grown for 24 hr. The removal efficiency ranged from 90.36% to 98.29% and was evaluated by measuring the fluorescence intensity of the biofilm as the treatment time was varied from 16 sec to 88 sec. We also performed experiments to compare the removal efficiencies with and without nitrogen purges; the measured biofilm removal efficiencies were not significantly different from each other (t-test, p &gt; 0.55). Therefore, this technique can be used to clean various bio-contaminated surfaces within one minute.

Biofilms on surfaces can be effectively and rapidly removed by using a periodic jet of carbon dioxide aerosols without a nitrogen purge.

La rimozione biofilm utilizzando spray di anidride carbonica senza azoto Purge

Biofilms can cause serious concerns in many applications. Not only can they cause economic losses, but they can also present a public health hazard. ...

Extraction of Organochlorine Pesticides from Plastic Pellets and Plastic Type Analysis

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment during manufacturing and transport. Because of their environmental persistence, they are widely distributed in the oceans and on beaches all over the world. They can act as a vector of potentially toxic organic compounds (e.g., polychlorinated biphenyls) and might consequently negatively affect marine organisms. Their possible impacts along the food chain are not yet well understood. In order to assess the hazards associated with the occurrence of plastic pellets in the marine environment, it is necessary to develop methodologies that allow for rapid determination of associated organic contaminant levels. The present protocol describes the different steps required for sampling resin pellets, analyzing adsorbed organochlorine pesticides (OCPs) and identifying the plastic type. The focus is on the extraction of OCPs from plastic pellets by means of a pressurized fluid extractor (PFE) and on the polymer chemical analysis applying Fourier Transform-InfraRed (FT-IR) spectroscopy. The developed methodology focuses on 11 OCPs and related compounds, including dichlorodiphenyltrichloroethane (DDT) and its two main metabolites, lindane and two production isomers, as well as the two biologically active isomers of technical endosulfan. This protocol constitutes a simple and rapid alternative to existing methodology for evaluating the concentration of organic contaminants adsorbed on plastic pieces.

Microplastics act as vector of potentially toxic organic contaminants with unpredictable effects. This protocol describes an alternative methodology for assessing the levels of organochlorine pesticides adsorbed on plastic pellets and identifying the polymer chemical structure. The focus is on pressurized fluid extraction and attenuated total reflectance Fourier transform infrared spectroscopy.

Estrazione di pesticidi di organochlorato da pellicole di plastica e analisi di tipo plastico

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment ...

Experimental Methods of Dust Charging and Mobilization on Surfaces with Exposure to Ultraviolet Radiation or Plasmas

Electrostatic dust transport has been hypothesized to explain a number of observations of unusual planetary phenomena. Here, it is demonstrated using three recently developed experiments in which dust particles are exposed to thermal plasma with beam electrons, beam electrons only, or ultraviolet (UV) radiation only. The UV light source has a narrow bandwidth in wavelength centered at 172 nm. The beam electrons with the energy of 120 eV are created with a negatively biased hot filament. When the vacuum chamber is filled with the argon gas, a thermal plasma is created in addition to the electron beam. Insulating dust particles of a few tens of microns in diameter are used in the experiments. Dust particles are recorded to be lofted to a height up to a few centimeters with a launch speed up to 1 m/s. These experiments demonstrate that photo and/or secondary electron emission from a dusty surface changes the charging mechanism of dust particles. According to the recently developed &#34;patched charge model&#34;, the emitted electrons can be re-absorbed inside microcavities between neighboring dust particles below the surface, causing the accumulation of enhanced negative charges on the surrounding dust particles. The repulsive forces between these negatively charged particles may be large enough to mobilize and lift them off the surface. These experiments present the advanced understanding of dust charging and transport on dusty surfaces, and laid a foundation for future investigations of its role in the surface evolution of airless planetary bodies.

Dust charging and mobilization is demonstrated in three experiments with exposure to thermal plasma with beam electrons, beam electrons only, or ultraviolet (UV) radiation only. These experiments present the advanced understanding of electrostatic dust transport and its role in shaping the surfaces of airless planetary bodies.

Metodi sperimentali di polvere carica e mobilitazione sulle superfici con l'esposizione a radiazione ultravioletta o plasmi

Electrostatic dust transport has been hypothesized to explain a number of observations of unusual planetary phenomena. Here, it is demonstrated using ...

In Situ Hybridization Techniques for Paraffin-Embedded Adult Coral Samples

Corals are important ocean invertebrates that are critical for overall ocean health as well as human health. However, due to human impacts such as rising ocean temperatures and ocean acidification, corals are increasingly under threat. To tackle these challenges, advances in cell and molecular biology have proven to be crucial for diagnosing the health of corals. Modifying some of the techniques commonly used in human medicine could greatly improve researchers&#39; ability to treat and save corals. To address this, a protocol for in situ hybridization used primarily in human medicine and evolutionary developmental biology has been adapted for use in adult corals under stress.
The purpose of this method is to visualize the spatial expression of an RNA probe in adult coral tissue that has been embedded in paraffin and sectioned onto glass slides. This method focuses on removal of the paraffin and rehydration of the sample, pretreatment of the sample to ensure permeability of the sample, pre-hybridization incubation, hybridization of the RNA probe, and visualization of the RNA probe. This is a powerful method when using non-model organisms to discover where specific genes are expressed, and the protocol can be easily adapted for other non-model organisms. However, the method is limited in that it is primarily qualitative, because expression intensity can vary depending on the amount of time used during the visualization step and the concentration of the probe. Furthermore, patience is required, as this protocol can take up to 5 days (and in many cases, longer) depending on the probe being used. Finally, non-specific background staining is common, but this limitation can be overcome.

In Situ Hybridization Techniques for Paraffin-Embedded Adult Coral Samples

The goal of this protocol is to perform in situ hybridization on adult coral samples that have been embedded in paraffin and sectioned onto glass slides. This is a qualitative method used to visualize the spatial expression of an RNA anti-sense probe in paraffin-embedded tissues.

In Situ Tecniche di ibridazione per paraffina adulti coralli campioni

Corals are important ocean invertebrates that are critical for overall ocean health as well as human health. However, due to human impacts such as rising ...

Sampling, Sorting, and Characterizing Microplastics in Aquatic Environments with High Suspended Sediment Loads and Large Floating Debris

The ubiquitous presence of plastic debris in the ocean is widely recognized by the public, scientific communities, and government agencies. However, only recently have microplastics in freshwater systems, such as rivers and lakes, been quantified. Microplastic sampling at the surface usually consists of deploying drift nets behind either a stationary or moving boat, which limits the sampling to environments with low levels of suspended sediments and floating or submerged debris. Previous studies that employed drift nets to collect microplastic debris typically used nets with &#8805;300 &#181;m mesh size, allowing plastic debris (particles and fibers) below this size to pass through the net and elude quantification. The protocol detailed here enables: 1) sample collection in environments with high suspended loads and floating or submerged debris and 2) the capture and quantification of microplastic particles and fibers &lt;300 &#181;m. Water samples were collected using a peristaltic pump in low-density polyethylene (PE) containers to be stored before filtering and analysis in the lab. Filtration was done with a custom-made microplastic filtration device containing detachable union joints that housed nylon mesh sieves and mixed cellulose ester membrane filters. Mesh sieves and membrane filters were examined with a stereomicroscope to quantify and separate microplastic particulates and fibers. These materials were then examined using a micro-attenuated total reflectance Fourier transform infrared spectrometer (micro ATR-FTIR) to determine microplastic polymer type. Recovery was measured by spiking samples using blue PE particulates and green nylon fibers; percent recovery was determined to be 100% for particulates and 92% for fibers. This protocol will guide similar studies on microplastics in high velocity rivers with high concentrations of sediment. With simple modifications to the peristaltic pump and filtration device, users can collect and analyze various sample volumes and particulate sizes.

Most microplastic research to date has occurred in marine systems where suspended solid levels are relatively low. Focus is now shifting to freshwater systems, which may feature high sediment loads and floating debris. This protocol addresses collecting and analyzing microplastic samples from aquatic environments that contain high suspended solid loads.

Campionamento, ordinamento e caratterizzando microplastiche negli ambienti acquatici con carichi di materiale solido in sospensione alta e grandi detriti galleggianti

The ubiquitous presence of plastic debris in the ocean is widely recognized by the public, scientific communities, and government agencies. However, only ...

Design and Use of an Apparatus for Quantifying Bivalve Suspension Feeding at Sea

As shellfish aquaculture moves from coastal embayments and estuaries to offshore locations, the need to quantify ecosystem interactions of farmed bivalves (i.e., mussels, oysters, and clams) presents new challenges. Quantitative data on the feeding behavior of suspension-feeding mollusks is necessary to determine important ecosystem interactions of offshore shellfish farms, including their carrying capacity, the competition with the zooplankton community, the availability of trophic resources at different depths, and the deposition to the benthos. The biodeposition method is used to quantify feeding variables in suspension-feeding bivalves in a natural setting and represents a more realistic proxy than laboratory experiments. This method, however, relies upon a stable platform to satisfy the requirements that water flow rates supplied to the shellfish remain constant and the bivalves are undisturbed. A flow-through device and process for using the biodeposition method to quantify the feeding of bivalve mollusks were modified from a land-based format for shipboard use by building a two-dimensional gimbal table around the device. Planimeter data reveal a minimal pitch and yaw of the chambers containing the test shellfish despite boat motion, the flow rates within the chambers remain constant, and operators are able to collect the biodeposits (feces and pseudofeces) with sufficient consistency to obtain accurate measurements of the bivalve clearance, filtration, selection, ingestion, rejection, and absorption at offshore shellfish aquaculture sites.

A flow-through device for using the biodeposition method to quantify filtration and feeding behavior of bivalve mollusks was modified for shipboard use. A two-dimensional gimbal table built around the device isolates the apparatus from boat motion, thereby allowing the accurate quantification of bivalve filtration variables at offshore shellfish aquaculture sites.

Progettazione e l'uso di un apparato per quantificare bivalvi sospensione alimentazione in mare

As shellfish aquaculture moves from coastal embayments and estuaries to offshore locations, the need to quantify ecosystem interactions of farmed bivalves ...