• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 101
  • 87
  • 29
  • 10
  • 9
  • 9
  • 9
  • 7
  • 4
  • 3
  • 2
  • 2
  • Tagged with
  • 312
  • 312
  • 35
  • 35
  • 31
  • 28
  • 27
  • 27
  • 26
  • 26
  • 26
  • 25
  • 24
  • 24
  • 20
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Indicative Bacteria in Stored Biosolids and Wastewater Associated Pharmaceuticals in the Environment

Wu, Chenxi 08 September 2010 (has links)
No description available.
272

Investigating the use of coca and other psychoactive plants in Pre-Columbian mummies from Chile and Peru. An analytical investigation into the feasibility of testing ancient hair for drug compounds.

Brown, Emma January 2012 (has links)
Psychoactive plants have played a significant role in Andean cultures for millennia. Whilst there is evidence of the importance of psychoactive plants in the Andean archaeological record, none of these are direct proof that these culturally significant plants were used by ancient Andean populations. This project utilised liquid chromatography tandem mass spectrometry (LC-MS/MS) to investigate the use of psychoactive plants in individuals from cemetery sites in Chile and Peru by analysing hair specimens for a variety of psychoactive compounds. Hair specimens from 46 individuals buried at cemetery sites in the Azapa Valley (northern Chile) belonging to the Cabuza culture (c AD 300 ¿ 1000) indicated around half of these people ingested coca, as evidenced by the detection of BZE in hair specimens. Two individuals from this population tested positive for bufotenine, the main alkaloid in Anadenanthera snuff. There is a specific material culture associated with snuffing. These findings confirm Anadenanthera was consumed in the Azapa Valley. The 11 individuals from Peru came from the necropolis at Puruchuco-Huaquerones in the Rímac valley near Lima. These individuals belonged to the Ichma culture, but would have been under Inca imperial control during the Late Horizon. Although only a small sample, two-thirds tested positive for BZE, suggestive that access to coca was widespread. This project presents a synthesis of the archaeological evidence for the use of various psychoactive plants in Andes. Also presented is the first report of the detection of bufotenine in ancient hair samples and additional data contributing to the understanding of the use of coca in the Andes. / Arts and Humanities Research Council (AHRC). Andy Jagger and Francis Raymond Hudson funds at the University of Bradford
273

Part 1 Design, Synthesis and Bioactivity of a Phosphorylated Prodrug for the Inhibition of Pin1; Part 2 Conformational Specificity of Cdc25c Substrate for Cdc2 Kinase using LC-MS/MS

Zhao, Song 18 January 2008 (has links)
The phosphorylation-dependent PPIase (peptidyl prolyl isomerase), Pin1 (Protein interacting with NIMA#1), has been found to regulate cell cycle through a simple conformational change, the cis-trans isomerization of phospho-Ser/Thr-Pro amide bonds. A variety of key cell cycle regulatory phosphoproteins, including Cdc25 phosphatase,Cdc27, p53 oncogene, c-Myc oncogene, Wee1 kinase, Myt1 kinase, and NIMA kinas, have been confirmed as substrates of Pin1. Pin1 was also observed to be overexpressed in a variety of cancer cell lines, and the inhibitors of Pin1 showed antiproliferative activities towards these cancer cells. These results implied that Pin1 might serve as a potential anti-cancer drug target. Besides, Pin1 has an important neuroprotective function and represents a potential new therapeutic agent for Alzheimer's disease. In order to understand the interaction between Pin1 and Cdc25c and the role of Pin1 in the mechanism for the regulation of mitosis, two amide isosteres, Ser-Ψ[(Z)CH=C]-Pro-OH and Ser-Ψ[(E)CH=C]-Pro-OH were incorporated into two peptidomimetics derived from human Cdc25c. Phosphorylation of these two peptidomimetics by the incubation with Cdc2 was studied using LC-MS/MS technique. It was found that Cdc2 kinase was conformationally specific to its Cdc25c substrate. Only the trans conformer of Cdc25c at its Ser168-Pro position can be recognized and phosphorylated by Cdc2 kinase, thereby creating the binding site for Pin1. In an effort to improve the cell permeability of the charged inhibitors of Pin1, bisPOM (pivaloyloxymethyl) prodrug moiety was introduced to mask the phosphate group of Fmoc-pSer-Ψ[(Z)CH=C]-Pro-(2)-N-(3)-ethylaminoindole, which is one inhibitor of Pin1. Fmoc-pSer-Ψ[(Z)CH=C]-Pro-(2)-N-(3)-ethylaminoindole and its bisPOM prodrug were synthesized efficiently starting with Boc-Ser-Ψ[(Z)CH=C]-Pro-OH in 24% and 12% yields respectively. The charged inhibitor showed a moderate inhibition towards Pin1 (IC50 = 28.3 μM). Its antiproliferative activity towards A2780 ovarian cancer cells (IC50 = 46.2 μM) was significantly improved by its bisPOM prodrug (IC50 = 26.9 μM), which is comparable to the IC50 of the charged inhibitor towards Pin1 enzymatic activity. These results not only established the bisPOM strategy as an efficient prodrug choice for Pin1 inhibitors, but also added additional evidence for Pin1 as a potential anticancer drug target. / Ph. D.
274

Utilizing Proteomic Techniques to Discover Host Protein Interactions with the E1 Glycoprotein of Venezuelan Equine Encephalitis Virus (VEEV) for Anti-Viral Discovery

Panny, Lauren E. 27 June 2023 (has links)
Venezuelan equine encephalitis virus (VEEV) is an alphavirus that causes disease in humans and equines eliciting both an agricultural and public health threat. In humans, the disease typically presents as a febrile illness with common signs of fever and malaise. Four to fourteen percent of Venezuelan equine encephalitis (VEE) cases are associated with severe neurological complications due to encephalitis caused by VEEV's propensity to infect the brain. Public health concerns are exacerbated by VEEV's aerosolization capabilities, low infectious dose and affordability to mass produce. These qualities drove interest in the pathogen as a bioweapon by the US and the former Soviet Union during the cold war. As a precautionary response to VEEV's notoriety as a biothreat, the National Institute of Allergies and Infectious Diseases has classified VEEV as a category B priority pathogen, and the Human Health Services and United States Department of Agriculture list live virulent strains of VEEV as a select agent and require the pathogen to be manipulated in highly regulated biosafety level 3 (BSL3) facilities. There are currently no FDA approved vaccines or antivirals to target VEEV or other closely related alphaviruses associated with clinical disease in humans. The research performed in this dissertation aimed to elucidate new antiviral targets and treatments to help bridge gaps in current understanding of alphaviruses. The current market lacks available antibodies for E1 specific isolation. In response, a recombinant VEEV TC-83 was produced with a V5 tag at the C-terminal of the E1 sequence to enable VEEV E1 detection. Sequencing was used to verify V5 insertion in the plasmid and immunoprecipitation was used to verify V5 insertion within the E1 glycoprotein. Replication kinetics experiments verified the virus replicated similarly to the parental VEEV TC-83 strain, while passaging experiments verified the tag was highly stable for up to 10 passages. This research produced a cost-effective and highly efficient means to probe and isolate the E1 glycoprotein without modifying the viability of the virus. Knowledge of host protein interactions with VEEV E1 glycoprotein has been limited, with most E1 research focusing on its fusion capabilities. Utilizing 293-T cells infected with E1-V5 TC-83, co-immunoprecipitation was performed to isolate E1 and associated interactors. A total of 486 host and 5 viral protein interactors of E1 were discovered after normalization to the negative control. The top peptide spectrum matches (PSMs) revealed a number of chaperone proteins and ubiquitin proteins as top interactors of VEEV E1. These results effectively revealed a number of previously unknown alphavirus interactions that can be targeted by antivirals and explored further for implications in viral replication. LC-MS/MS results showed that protein disulfide isomerase family A member 6 (PDIA6) interacted with E1. High PSMs, presence in all 3 replicates, similar cellular localization to E1 and known associations between other viruses and protein disulfide isomerase (PDI) family members made this protein an optimum target for further analysis. Co-immunoprecipitation and co-localization experiments were used to validate the LC-MS/MS results. Involvement of PDIs in VEEV replication were explored utilizing two known PDI inhibitors, LOC14 and Nitazoxanide. LOC14, a non-FDA approved broad-spectrum PDI inhibitor, showed broad-spectrum alphavirus antiviral potential, decreasing titers of VEEV TC-83, VEEV Trinidad Donkey strain, eastern equine encephalitis virus (EEEV), chikungunya virus (CHIKV) and Sindbis (SINV) virus in a dose dependent manner. Nitazoxanide, an FDA approved drug known to inhibit PDIA3, was shown to have minimal toxicity and effectively reduced VEEV TC-83 and EEEV titers at concentrations with 100% cell viability. Time of addition assays, E1 expression time course studies, and early event assays showed PDI inhibition with these drugs effects early viral production events. RNA quantification, confocal microscopy and biotin switch assay experiments show that the drugs also prevented proper folding of the E1 glycoprotein and decreased expression of E1 on the peripheral membrane. With no current treatments for alphaviruses, these data provide an effective broad-spectrum target that affects viral replication at multiple stages in-vitro. Nitazoxanide also presents as a promising, non-toxic drug that could be repurposed to combat a number of clinically relevant alphaviruses. Valosin containing protein (VCP) was also shown to interact with the E1 glycoprotein. Exploration of VCP's interaction with alphavirus E1 has never been explored, yet it was previously shown to be involved in alphavirus replication. Co-localization and co-immunoprecipitation experiments were performed validating the interaction between VCP and E1. siRNA knockdown of VCP in 293-T cells and U87-MG cells showed a significant reduction in VEEV TC-83 titers. The allosteric VCP inhibitor, NMS-873, also reduced VEEV TC-83 titers, but was shown to be less effective against CHIKV, SINV and EEEV, suggesting the NMS-873 mechanism is more selective for VEEV. Mechanism experiments showed that reduction of VCP with NMS-873 inhibits early events of VEEV replication. These results elucidate VCP's association with E1 and show that VCP can be targeted to decrease VEEV viral replication. / Doctor of Philosophy / Venezuelan equine encephalitis virus (VEEV) causes disease in humans, as well as horses, donkeys and other closely related animals. In humans, the virus causes a flu-like disease and sometimes swelling of the brain. This can be associated with symptoms such as light sensitivity, confusion and sometimes coma. Prior to the Cold War, VEEV was researched by the US and previous Soviet Union's militaries in hopes to deploy the virus as a bioweapon. Current treaties prevent active production of such weapons, yet allows for defensive research to continue in preparation for a worst-case scenario. Currently no FDA approved medications or vaccines exist to combat the virus further exacerbating concerns. In order to protect laboratorians and prevent unintentional or intentional introduction of the virus into the community, the virus is only manipulated in highly secure facilities with barriers that separate the virus from personnel and the outside environment. A component of the virus called E1, allows for the virus to be released from a structure, called an endosome, that transports the virus into the cell. Currently, E1 is mostly known for this function, yet our research found that E1 interacts with 486 protein components of the host cell, suggesting a more elaborate role of E1 than previously understood. This list of interactors provides numerous new targets for potential medications to combat VEEV and other closely related viruses. Discovered E1 interactors, protein disulfide isomerase family A member 6 (PDIA6) and valosin containing protein (VCP), were validated through extensive experimentation and their function in viral replication was further explored. Protein disulfide isomerases (PDI), such as PDIA6, play an important role in folding proteins, which are cellular components made of organic building blocks called amino acids. PDIs do so by creating organic pillars, called disulfide bonds, between two cysteine amino acid residues. These disulfide bonds contribute to the 3D shape of the proteins they fold which are essential for the protein's function. E1 of VEEV has a total of eight disulfide bonds within its structure, highlighting that disulfide bonds are likely essential for the protein's structure, and therefore, function. We verified that E1 could not properly fold without PDI function by using two compounds that prevented PDI from forming or breaking disulfide bonds, specifically LOC14 and FDA approved drug nitazoxanide. Cells treated with one of either compound before and after infection with VEEV, were found to produce E1 protein with significantly less disulfide bonds therefore producing less viable virus. Further experiments also showed that the compounds also affected early stages in the virus production cycle. These two mechanisms explain the significant reduction in production of VEEV and related viruses when PDI is inhibited. These results provide a new VEEV drug target, PDIs, as well as two compounds that can potentially be used to combat VEEV and other related viruses that have no current treatment options. Another host interactor, VCP, functions throughout the cell and is known for unfolding of numerous substrates, including proteins. It is involved in numerous cellular functions thus making this interactor a promising target for drug treatment. Cells with reduced VCP function were shown to produce less progeny VEEV. Cells treated with NMS-873, a compound that reduces VCP function was also shown to reduce VEEV production. NMS-863 inhibition of VCP was shown to effect early events in VEEV replication. These results further emphasize the E1 interactors discovered are invaluable novel targets for VEEV drug treatment.
275

Das Dauerstadium als Präadaptation

Chang, Zisong 08 January 2015 (has links)
Wir fanden konservierte molekulare Signaturen der Regulation durch Δ7-DA und Ascarosid bei Dauer- und infektiösen Larven. Danach wurde die hohe Konservierung durch unsere Analyse in Dauer- und Postdauer-Stadium zwischen den zwei nah verwandten freilebenden Arten C. elegans und C. briggsae identifiziert. Das heißt, dass die relative Veränderung auf mRNA- oder Protein- Ebene zwischen zwei Arten stark korreliert ist. Aber die relative Veränderung innerhalb derselben Art zeigt keine hochgradige Korrelation zwischen mRNA- und Protein-Ebene. Unsere Ergebnisse zeigen in C. elegans Dauerlarven die signifikante Reduzierung der RNA-Mengen in 20 Stoffwechselwegen. Im Gegensatz dazu speicherten Dauerlarven reichlich RNA-Mengen in GO Termen wie Ribosome und Aminoacyl-tRNA biosynthesis. Auf Protein-Ebene sind die Stoffwechselwege von Proteinsynthese und Proteinverarbeitung im endoplasmatischen Retikulum in Dauerlarven herunterreguliert und GO Terme wie Lysosome sind hochreguliert. Durch die Zeitreihenanalyse der Proteom-Remodellierung der molekularen Signaturen beim Austritt aus dem Dauer-Stadium fand wir, dass GO Terme wie metal ion binding signifikant herunterreguliert sind und der Proteinabbau hochreguliert ist. Unsere Ergebnisse vom pSILAC Experiment deuten an, dass die Proteine für Energieerzeugung und Chaperone/Proteinfaltung beim Daueraustritt schnell verbraucht sind und wieder hergestellt werden. Zum Schluss haben wir als Erste den popomR-Assay in C. elegans etabliert und ein Screening der vermeintlichen Proteinbindestellen auf poly-A-RNA durchgeführt, um in der Zukunft die konservierten Mechanismen der post-transkriptionellen Regulation durch RBPs im Dauer-Stadium zu analysieren. / We found the conservation of molecular signatures by regulating with Δ7-DA and Ascarosid in dauer larvae and infective larvae. Then by our comparative analysis, the high degree of conservation between two closely related free-living species C. elegans and C. briggsae was identified in dauer and post-dauer stages. This means that the relative changes are strongly correlated on the mRNA or the protein level between two species. But the relative changes in the same species don’t show any strong correlation between the mRNA and the protein levels. Our results showed a significantly reduced amount of RNA in 20 metabolic pathways in C. elegans dauer larvae. In contrast, dauer larvae stored a large amount of RNA in GO terms such as ribosome and aminoacyl-tRNA biosynthesis. On the protein level, the metabolic pathways of protein synthesis and protein processing in endoplasmic reticulum were downregulated in dauer larvae and the term of lysosome was up-regulated. Due to time course analysis for proteome remodeling of molecular signatures during exit process from dauer stage, we found that GO terms such as metal ion binding were significantly downregulated during dauer exit and at the same time the protein degradation was up-regulated. Our results of pSILAC experiment suggest that the proteins for energy generation and chaperone/protein folding are quickly spent and rebuilded during dauer exit. Finally, we were the first to establish the popomR assay in C. elegans and performed a screening of the putative protein binding sites on poly-A RNA to analyze the conserved mechanisms of post-transcriptional regulation by RBPs in dauer larvae in the future.
276

Ispitivanja odabranih predstavnika podfamilije Polygonoideae (Polygonaceae A.L. de Jussieu 1789) sa područja centralnog i zapadnog Balkana. Fitohemijski i biohemijski aspekti / Phytochemical and biochemical analysis of selected species of subfamily Polygonoideae (Polygonaceae A. L. de Jussieu 1789) from Central and Western Balkan regions.

Svirčev Emilija 24 September 2014 (has links)
<p>U ovoj doktorskoj disertaciji prikazani su rezultati istraživanja 15&nbsp;vrsta&nbsp; biljaka&nbsp; koje&nbsp; pripadaju&nbsp; rodovima <em>Rumex,&nbsp; Polygonum,&nbsp;Bistorta,&nbsp; Persicaria i&nbsp; Fagopyrum,</em>&nbsp; podfamilije&nbsp; Polygonoideae,&nbsp;familije&nbsp; Polygonaceae,&nbsp; sakupljenih&nbsp; na&nbsp; teritoriji&nbsp; centralnog&nbsp; i&nbsp;zapadnog &nbsp;Balkana u periodu od 2009-2011. godine. Sprovedena&nbsp;istraživanja&nbsp; su&nbsp; se&nbsp; odvijala&nbsp; u&nbsp; dva&nbsp; pravca:&nbsp; fitohemijska&nbsp; i&nbsp;biohemijsko-biolo&scaron;ka&nbsp; ispitivanja.&nbsp; Predmet&nbsp; analiza&nbsp; bili&nbsp; su&nbsp;ekstrakti&nbsp; herbi&nbsp; i&nbsp; rizoma&nbsp; ispitivanih&nbsp; biljaka.&nbsp; Fitohemijska&nbsp;ispitivanja&nbsp; obuhvatila&nbsp; su,&nbsp; pored&nbsp; spektrofotometrijskog&nbsp;određivanja&nbsp; ukupnih&nbsp; fenola,&nbsp; ukupnih&nbsp; flavonoida&nbsp; i&nbsp; ukupnih&nbsp;antrahinonskih jedinjenja, i određivanje sadržaja 51 komponente&nbsp;iz standardne sme&scaron;e različitih klasa fenolnih jedinjenja LC-MSMS&nbsp; metodom,&nbsp; odnosno &nbsp;hromatografsko&nbsp; profilisanje&nbsp; ekstrakata&nbsp;LC-DAD-MS&nbsp; metodom.&nbsp; Odabirom&nbsp; nekoliko&nbsp; različitih&nbsp; model&nbsp;sistema&nbsp; za&nbsp; merenje&nbsp; antioksidantne&nbsp; aktivnosti&nbsp; (neutralizacija&nbsp;DPPH&nbsp; radikala,&nbsp; redoks&nbsp; kapacitet&nbsp; -&nbsp; FRAP&nbsp; test,&nbsp; skevindžer&nbsp;aktivnost&nbsp; prema&nbsp; superoksidanjon&nbsp; radikalu,&nbsp; NO&nbsp; radikalu&nbsp; i&nbsp; OH&nbsp;radikalu,&nbsp; kao&nbsp; i&nbsp; inhibicija&nbsp; lipidne&nbsp; peroksidacije)&nbsp; procenjen&nbsp; je&nbsp;antioksidantni&nbsp; potencijal&nbsp; ekstrakata,&nbsp; dok&nbsp; je&nbsp; za&nbsp; procenu&nbsp; njihove&nbsp;antiinflamatorne&nbsp; aktivnosti&nbsp; kori&scaron;ćen&nbsp; potencijal&nbsp; inhibicije&nbsp;biosinteze medijatora inflamacije u humanim trombocitima (kao&nbsp;model&nbsp; sistemu).&nbsp; Mikrobiolo&scaron;ka&nbsp; ispitivanja&nbsp; su&nbsp; obuhvatila&nbsp;određivanje&nbsp; potencijala&nbsp; ovih&nbsp; vrsta&nbsp; u&nbsp; inhibiciji&nbsp; rasta&nbsp; serije&nbsp; gram&nbsp;pozitivnih i gram negativnih sojeva batkerija. Konačno, urađena&nbsp;je&nbsp; analiza&nbsp; korelacije&nbsp; hemijskog&nbsp; sastava,&nbsp; biolo&scaron;ke&nbsp; aktivnosti&nbsp; i&nbsp;pripadnosti taksonomskim grupama.</p> / <p>Phytochemical&nbsp; and&nbsp; biochemical&nbsp; analysis&nbsp; of&nbsp; herbal&nbsp; and&nbsp; root&nbsp;ethanol&nbsp; extracts&nbsp; of&nbsp; 15&nbsp; species&nbsp; belonging&nbsp; to&nbsp; different&nbsp; genera&nbsp;(<em>Rumex,&nbsp; Polygonum,&nbsp; Bistorta,&nbsp; Persicaria and&nbsp; Fagopyrum</em>)&nbsp; of&nbsp;subfamily&nbsp; Polygonoideae,&nbsp; was&nbsp; examined.&nbsp; Phytochemical&nbsp;characterization&nbsp; included&nbsp; spectrophotometric&nbsp; determination&nbsp; of&nbsp;total&nbsp; phenolic,&nbsp; total&nbsp; flavonoids&nbsp; and&nbsp; total&nbsp; anthraquinone&nbsp; contents,&nbsp;quantification&nbsp; of&nbsp; 51&nbsp; secondary&nbsp; metabolites&nbsp; by&nbsp; LC/MS/MS&nbsp;analysis&nbsp; and&nbsp; chromatographic&nbsp; fingerprinting by&nbsp; LC/DAD/MS&nbsp;technique,&nbsp; of&nbsp; prepared&nbsp; extracts.&nbsp; The&nbsp; antioxidant&nbsp; activity&nbsp; was&nbsp;evaluated&nbsp; by&nbsp; measuring&nbsp; ferric&nbsp; reducing&nbsp; ability&nbsp; (FRAP)&nbsp; of&nbsp; the&nbsp;extracts and their radical scavenging capacity towards DPPH, OH,&nbsp;NO and O<sub>2</sub><sup>&ndash;&nbsp;</sup>radicals, and inhibition of lipid peroxidation). Antiinflammatory activity was evaluated by LC/MS/MS monitoring of&nbsp;selected&nbsp; metabolites&nbsp; (12-(S)-HHT,&nbsp; 12(S)-HETE,&nbsp; PGE<sub>2&nbsp;</sub>,&nbsp; PGF<sub>2&alpha;</sub>,&nbsp;and TXB<sub>2</sub>) formed in cyclooxygenase and lipoxygenase pathways&nbsp;of arachidonic acid metabolism. Human platelets were used as a&nbsp;source&nbsp; of&nbsp; enzymes,&nbsp; while&nbsp; inflammation&nbsp; was&nbsp; induced&nbsp; by&nbsp;calcimycin. The antibacterial activity of prepared&nbsp; extracts against&nbsp;nine&nbsp; bacterial&nbsp; strains&nbsp; was&nbsp; evaluated&nbsp; by&nbsp; microtiter&nbsp; assay&nbsp; with&nbsp;resazurin as a colorimetric growth indicator.</p>
277

Fotokatalitička aktivnost dopovanog titan(IV)-oksida u razgradnji nekih pesticida / Photocatalytic activity of doped titanium(IV)-oxide in degradation processes of some pesticides

Šojić Daniela 08 July 2009 (has links)
<p>Kao &scaron;to je poznato, RS-2-(4-hlor-o-toliloksi)propionska kiselina (MCPP),&nbsp;(4-hlor-2-metilfenoksi)sirćetna kiselina (MCPA) i 3,6-dihlorpiridin-2-karboksilna kiselina &nbsp;(klopiralid) su herbicidi sa veoma &scaron;irokim spektrom dejstva, a pored toga su rastvorljivi u&nbsp;vodi, te&scaron;ko biorazgradljivi i prema literaturnim podacima su, nažalost, veoma često prisutni&nbsp;herbicidi u pijaćoj vodi. Proces heterogene fotokatalize uz primenu TiO<sub>2</sub>i UV zračenja se&nbsp;pokazao kao veoma pogodan način za njihovo uklanjanje iz vode. Međutim, zbog velikog&nbsp;energetskog procepa od 3,2 eV (anataze-oblik), odnosno, 3,0 eV (rutil-oblik), veoma mali&nbsp;udeo bliskih UV zraka iz sunčeve svetlosti (oko 3&minus;4%) biva iskori&scaron;ćen u toku&nbsp;fotokatalitičkog procesa, &scaron;to ukazuje na to da je TiO<sub>2&nbsp;</sub>praktično neaktivan u prisustvu&nbsp;sunčeve svetlosti. Na osnovu literaturnih podataka je zapaženo da postoji mogućnost&nbsp;fotorazgradnje pojedinih supstrata u prisustvu TiO<sub>2&nbsp;</sub>primenom vidljive svetlosti. Na&nbsp;primeru MCPP je ispitana aktivnost TiO<sub>2&nbsp;</sub>Degussa P25 kao fotokatalizatora u prisustvu&nbsp;vidljive svetlosti. Na osnovu refleksionih spektara je utvrđeno da MCPP adsorbovan na&nbsp;TiO<sub>2&nbsp;</sub>Degussa P25 apsorbuje vidljivi deo spektra (&lambda; &ge;400 nm). Nastali prelazni kompleks&nbsp;je potvrđen FTIR merenjima. Efikasnost TiO2Degussa P25 primenom vidljive svetlosti je&nbsp;upoređena sa sunčevim i UV zračenjem, kao i direktnom fotolizom u prisustvu pomenutih&nbsp;izvora zračenja. Brzina fotokatalitičke razgradnje MCPP primenom vidljive svetlosti iznosi&nbsp;0,86 &mu;mol dm<sup>&minus;3</sup>min<sup>&minus;1</sup>, &scaron;to je oko 4 puta brže u poređenju sa direktnom fotolizom. Nadalje&nbsp;je ustanovljena optimalna masena koncentracija katalizatora od oko 8 mg cm<sup>&minus;3</sup>, koja je&nbsp;znatno vi&scaron;a u poređenju sa primenom UV zračenja. Razlog je najverovatnije različit&nbsp;mehanizam fotorazgradnje koji se odvija primenom vidljivog i UV zračenja. Naime,&nbsp;prisustvo 2-metil-2-propanola (poznatog hvatača&nbsp;<sup>&bull;</sup>OH-radikala) praktično ne utiče na&nbsp;brzinu fotokatalitičke razgradnje MCPP p rimenom vidljive svetlosti, &scaron;to ukazuje da se&nbsp;mehanizam razgradnje MCPP primenom &nbsp;vidljive svetlosti ne odvija posredstvom&nbsp;<sup>&bull;</sup>OH-radikala, za razliku od onog uz primenu UV zračenja.</p><p>S obzirom da se katalizator TiO<sub>2&nbsp;</sub>Degussa P25 uz primenu vidljive svetlosti nije&nbsp;<br />pokazao kao naročito efikasan kada je u pitanju razgradnja sva tri herbicida i imajući u&nbsp;vidu da se u poslednje vreme iz razloga praktične primene sve vi&scaron;e pribegava procesu dopovanja TiO<sub>2&nbsp;</sub>različitim tipovima metala (alkalnih, zemnoalkalnih, prelaznih i dr.) i nemetala (halogenida, halkogenida i dr.), u okviru ove doktorske disertacije je ispitana aktivnost N-TiO<sub>2 </sub>(sintetisanih mokrim i suvim putem) i TiO<sub>2&nbsp;</sub>(rutil) dopovanog sa različitim količinama Fe<sup>3+</sup>-jona (0,13&minus;1,48 at.%) pri razgradnji herbicida MCPP i MCPA primenom vidljive svetlosti. Pored toga je ispitana efikasnost TiO<sub>2&nbsp;</sub>(anataze) takođe dopovanog sa različitim količinama Fe<sup>3+</sup>-jona (0,71&minus;1,80 at.%) na primeru MCPP.&nbsp;</p><p>Poredeći N-TiO<sub>2&nbsp;</sub>(sintetisan mokrim putem) i N-TiO<sub>2&nbsp;</sub>(sintetisani suvim putem), primećeno&nbsp;je da je u drugom slučaju efikasnost katalizatora veća oko 2 puta. Isto tako je zapažena u&nbsp;slučaju MCPP ne&scaron;to veća fotokatalitička aktivnost N-TiO<sub>2&nbsp;</sub>(sintetisani suvim putem) u&nbsp;poređenju sa TiO<sub>2&nbsp;</sub>(anataze). Kada je u pitanju MCPA aktivnost sva tri katalizatora je&nbsp;veoma slična. Pored toga je zapažena veća efikasnost N-TiO<sub>2&nbsp;</sub>(sintetisan mokrim putem) u&nbsp;poređenju sa TiO<sub>2&nbsp;</sub>Degussa P25 (oko 1,5 puta) i oko 5 puta u odnosu na direktnu fotolizu,&nbsp;dok su N-TiO<sub>2&nbsp;</sub>(sintetisani suvim putem) oko 3 puta efikasniji u poređenju sa TiO<sub>2&nbsp;</sub>Degussa P25 i oko 10 puta u &nbsp;poređenju sa direktnom fotolizom. Brzina solarne razgradnje&nbsp;je preko 100 puta manja nego primenom vidljivog i UV zračenja, &scaron;to je posledica različitih&nbsp;intenziteta pomenutih izvora ozračivanja i različitih uslova pri kojima je vr&scaron;ena razgradnja. &nbsp;Ustanovljena je optimalna masena koncentracija N-TiO<sub>2&nbsp;</sub>(sintetisan mokrim putem) od&nbsp;4 mg cm<sup>&minus;3</sup>.</p><p>Prilikom razgradnje MCPP i MCPA je nađeno da je brzina veća kada se kao&nbsp;katalizator &nbsp;koristi TiO<sub>2&nbsp;</sub>(rutil) u poređenju sa Fe-TiO<sub>2&nbsp;</sub>i da sa povećanjem količine Fe<sup>3+</sup>-jona fotokatalitička aktivnost uglavnom opada. Kada je kao fotokatalizator kori&scaron;ćen TiO<sub>2 &nbsp;</sub><br />(anataze) dopovan različitim količinama Fe<sup>3+</sup>-jona (od 0,71 do 1,80 at.%), razgradnja&nbsp;<br />MCPP je u svim slučajevima znatno sporija u odnosu na TiO<sub>2&nbsp;</sub>(anataze).</p><p>S obzirom da su prema literaturnim podacima kinetika i mehanizam fotokatalitičke&nbsp;<br />razgradnje klopiralida nepoznati, ispitana je njegova stabilnost pri različitim&nbsp;eksperimentalnim uslovima. Tokom ispitivanja uticaja pH kako u prisustvu, tako i u&nbsp;odsustvu dnevne svetlosti u intervalu pH od 1,0&minus;9,0, nađeno je da ni u jednom slučaju ne&nbsp;dolazi do razgradnje supstrata u periodu od sedam meseci koliko je proces praćen. Takođe&nbsp;je ispitana kinetika fotokatalitičke razgradnje klopiralida primenom UV i vidljivog&nbsp;zračenja u prisustvu TiO<sub>2&nbsp;</sub>Degussa P25, kao i direktna fotoliza primenom oba izvora&nbsp;zračenja. Nađeno je da je brzina fotokatalitičke razgradnje primenom UV zračenja veća&nbsp;oko 5 puta u odnosu na direktnu fotolizu. Za praćenje toka fotokatalitičke razgradnje&nbsp;klopiralida je izabrana pH-vrednost od 3,2. Nadalje je zapaženo da se u ispitivanom opsegu početnih koncentracija supstrata (0,5&ndash;3,0 mmol dm<sup>&minus;3</sup>) kinetika fotokatalitičke razgradnje klopiralida može opisati pseudo-prvim redom. Pri ispitivanju uticaja masene koncentracije katalizatora (0,5&ndash;8 mg cm<sup>&minus;3</sup>) na brzinu razgradnje klopiralida, ustanovljena je optimalna masena koncentracija primenjenog fotokatalizatora od oko 4 mg cm<sup>&minus;3</sup>. Izračunata ukupna &nbsp;prividna energija aktivacije iznosi 7,74 kJ mol<sup>&minus;1</sup>. Pored toga, prisustvo kiseonika ubrzava reakciju 2 puta, dok dodatak elektron-akceptora kao &scaron;to su (NH<sub>4</sub>)<sub>2</sub>S<sub>2</sub>O<sub>8</sub>, H<sub>2</sub>O<sub>2&nbsp;</sub>i KBrO<sub>3&nbsp;</sub>pokazuje značajan i različit efekat na kinetiku fotokatalitičke razgradnje klopiralida. Pri ispitivanju uticaja etanola, kao hvatača slobodnih radikala, nađeno je da se heterogena fotokataliza odvija uglavnom preko <sup>&bull;</sup>OH-radikala.</p><p>Na osnovu LC&ndash;MS/MS (ESI+) merenja ustanovljeno je prisustvo nekoliko&nbsp;intermedijera: 3,6-dihlor-piridin-2-ol, 3,6-dihlor hidroksipiridin-2-karboksilna kiselina i&nbsp;3,3&#39;,6,6&#39;-tetrahlor-2,4&#39;-bipiridin-2&#39;-karboksilna kiselina. Na osnovu identifikovanih&nbsp;intermedijera, kao i kinetičkih rezultata, predložen je mogućput mehanizma fotokatalitičke&nbsp;razgradnje klopiralida.</p><p>Prilikom ispitivanja uticaja strukture molekula na brzinu razgradnje, konstatovano&nbsp;<br />je da u slučaju klopiralida praktično ne dolazi do fotokatalitičke razgradnje u prisustvu&nbsp;TiO<sub>2&nbsp;</sub>(anataze) i N-TiO<sub>2&nbsp;</sub>(sintetisani suvim putem) uz primenu vidljive svetlosti, kao i u&nbsp;slučaju TiO<sub>2&nbsp;</sub>Degussa P25. Pored toga, primenom TiO<sub>2&nbsp;</sub>(rutil) i Fe-TiO<sub>2&nbsp;</sub>kao&nbsp;fotokatalizatora, sa povećanjem količine Fe<sup>3+</sup>-jona od 0,13 do 1,27 at.% raste brzina&nbsp;razgradnje klopiralida, ukazujući da strukturne osobine supstrata utiču na brzinu njihove&nbsp;razgradnje.</p> / <p>It is well known that RS-2-(4-chloro-o-tolyloxy)propionic acid (MCPP), (4-chloro-2- methyl-phenoxy)acetic acid (MCPA) and 3,6-dichloropyridine-2-carboxylic &nbsp;acid&nbsp;(clopyralid) are herbicides of wide activity spectrum. They are soluble in water, hardly&nbsp;biodegradable and, unfortunately, often present in drinking water.</p><p>Heterogeneous photocatalysis by application of TiO<sub>2&nbsp;</sub>and UV radiation proved to&nbsp;be very suitable for their removal from water. However, due toits large energy gap, i.e.&nbsp;3.2 &nbsp;eV (anatase-form) and 3.0 eV (rutile-form), a very small fraction of sunlight in the near&nbsp;UV range (about 3&ndash;4%) is used during photocatalytic process, which is an indication of&nbsp;TiO<sub>2&nbsp;</sub>inactivity in the presence of this light source. Some literature data report on the&nbsp;possibility of photodegradation of certain substrates by visible light in the presence of&nbsp;TiO<sub>2</sub>. MCPP served as substrate for testing TiO<sub>2&nbsp;</sub>Degussa P25 &nbsp;photocatalytic activity in the&nbsp;presence of visible light. On the basis of reflection spectra it was established that MCPP&nbsp;adsorbed on TiO<sub>2&nbsp;</sub>Degussa P25 was absorbing visible spectrum radiation (&lambda; &ge;400 nm).&nbsp;The existence of thus formed &nbsp;charge-transfer complex was confirmed with FTIR analysis.&nbsp;The efficiency of &nbsp;TiO<sub>2&nbsp;</sub>Degussa P25 with application of visible light was compared to&nbsp;sunlight and UV radiation, as well to directphotolysis in the presence of these light&nbsp;sources. The rate of MCPP photocatalytic degradation by means of visible light is&nbsp;0.86 &mu;mol dm<sup>&minus;3&nbsp;</sup>min<sup>&minus;1</sup>, which is about 4 times faster than direct photolysis. In addition, the&nbsp;optimal &nbsp;catalyst concentration of about 8 mg cm<sup>&minus;3</sup>, much higher than using UV radiation,&nbsp;<br />was established. The reason is, probably, a different mechanism of &nbsp;hotodegradation &nbsp;in the&nbsp;presence of visible and UV irradiation. Namely, the presence of 2-methyl-2-propanol&nbsp;(well-known&nbsp;<sup>&bull;</sup>OH radical scavenger) has practicallyno effect on the rate of &nbsp;MCPP&nbsp;photocatalytic degradation using visible light, which points that this degradation&nbsp;mechanism does not involve&nbsp;<sup>&bull;</sup>OH radicals, in contrast to that established &nbsp;for UV radiation.</p><p>Since the catalyst TiO<sub>2&nbsp;</sub>Degussa P25 with application of visible light was not very&nbsp;<br />efficient in degradation of all three herbicidesand in view that nowadays is very &nbsp;popular&nbsp;doping process of TiO<sub>2</sub> with different types of metals (alkali, alkaline-earth, transition, etc.)&nbsp;and non-metals (halogen, chalcogen, etc.), in the scope of this Ph.D. &nbsp;thesis activities of N-TiO<sub>2&nbsp;</sub>(synthesized by wet and dry procedure) and TiO<sub>2&nbsp;</sub>(rutile) doped with various amounts&nbsp;of Fe<sup>3+&nbsp;</sup>(0.13&ndash;1.48 at.%) in degradation processes of &nbsp;herbicides MCPP and MCPA using&nbsp;visible light were studied. In addition, the efficiency of TiO<sub>2&nbsp;</sub>(anatase) doped with various&nbsp;amounts of Fe<sup>3+&nbsp;</sup>(0.71&ndash;1.80 at.%) was also tested for MCPP degradation. When comparing&nbsp;N-TiO<sub>2&nbsp;</sub>(synthesized by wet procedure) and N-TiO<sub>2</sub> (dry procedure), it was observed that&nbsp;in the latter case the catalyst efficiency was about two times higher. In this case for MCPP&nbsp;was also observed somewhat higher photocatalytic activity of N-TiO<sub>2</sub> (synthesized by dry&nbsp;procedure) in comparison with TiO<sub>2</sub>. When activities of all three catalysts towards MCPA&nbsp;are compared, the results are very alike. In addition, higher efficiency of N-TiO<sub>2 &nbsp;</sub>(wet&nbsp;procedure) comparing to TiO<sub>2&nbsp;</sub>Degussa P25 (about 1.5 times) and about 5 times in&nbsp;comparison to direct photolysis were recorded, while N-TiO<sub>2</sub> (dry procedure) was about 3&nbsp;times more efficient than TiO<sub>2&nbsp;</sub>Degussa P25 and about 10 times in comparison with direct&nbsp;photolysis. The rate of solar degradation is about 100 times lower than by application of&nbsp;UV and visible radiation, as a consequence of various intensities of the mentioned light&nbsp;sources and different conditions of photodegradation. An optimal concentration of N-TiO<sub>2</sub>&nbsp;(wet procedure) of 4 mg cm<sup>&minus;3</sup><br />&nbsp;was established.</p><p>During degradation of MCPP and MCPA it was observed that the rate is higher if&nbsp;TiO<sub>2 </sub>(rutile) was applied comparing to Fe-TiO<sub>2&nbsp;</sub>and with increasing amount of Fe<sup>3+&nbsp;</sup>photocatalytic activity mostly decreases. When TiO<sub>2</sub> (anatase) doped with various amounts&nbsp;of Fe<sup>3+&nbsp;</sup>(0.71 to 1.80 at.%) was applied for MCPP degradation, the process was much&nbsp;slower than with undoped catalyst.</p><p>Since we have not found relevant literature data on kinetics and mechanism of&nbsp;photocatalytic degradation of clopyralid, its stability in different experimental conditions&nbsp;was tested. In investigating of influences of pH (1.0&ndash;9.0) both in presence and in absence&nbsp;of daylight, in no cases decomposition was observed during seven months experiments.&nbsp;Also, the kinetics of photocatalytic degradation of clopyralid using UV and visible&nbsp;irradiation in the presence of TiO<sub>2&nbsp;</sub>Degussa P25 and in direct photolysis by application of&nbsp;both irradiation sources was studied. It was found that the &nbsp;rate of photocatalytic&nbsp;decomposition using UV radiation was 5 times higher comparing to direct photolysis. For&nbsp;clopyralid photocatalytic monitoring a pH value of &nbsp;3.2 was chosen. In addition, in the investigated concentration range (0.5&ndash;3.0 mmol &nbsp;dm<sup>&minus;3</sup>) the photocatalytic degradation kinetics of clopyralid in the first stage of the reaction follows approximately a pseudo-first kinetic order. In investigation of influence of catalyst concentration (0.5&ndash;8 mg cm<sup>&minus;3</sup>) on the rate of clopyralid degradation the highest reaction rate was observed at 4 mg cm<sup>&minus;3&nbsp;</sup>of catalyst concentration The apparent activation energy of the reaction being 7.74 kJ mol<sup>&minus;1</sup>. The absence of molecular oxygen resulted in a significant decrease (about 2 times) in the rate of clopyralid photodegradation. The effect of the presence of (NH<sub>4</sub>)<sub>2</sub>S<sub>2</sub>O<sub>8</sub>, H<sub>2</sub>O<sub>2&nbsp;</sub>and KBrO<sub>3</sub>, acting as electron acceptors along with molecular oxygen affects clopyralid photocatalytic degradation considerably and indifferent ways. By studying the effect of ethanol as a hydroxyl radical scavenger it was shown that the heterogeneous catalysis takes place mainly via <sup>&bull;</sup>OH radicals.</p><p>LC&minus;MS/MS (ESI+) monitoring of the process showed that several pyridine-containing intermediates are formed: 3,6-dichloropyridin-2-ol, 3,6-dichloro&nbsp;hydroxypyridine-2-carboxylic acid and 3,3&#39;,6,6&#39;-tetrachloro-2,4&#39;-bipyridine-2-carboxylic&nbsp;acid. Based on the identified intermediates and overall kinetic results, a probable&nbsp;photocatalytic degradation mechanism was proposed.&nbsp;</p><p>Finally, in the case of clopyralid it was established that practically no degradation&nbsp;<br />occurs in the presence of TiO<sub>2&nbsp;</sub>(anatase) and N-TiO<sub>2</sub> (dry procedure) with visible light &nbsp;and&nbsp;also with TiO<sub>2&nbsp;</sub>Degussa P25. Besides of that, by using TiO<sub>2&nbsp;</sub>(rutile) and Fe-TiO<sub>2&nbsp;</sub>as&nbsp;photocatalysts it was noted that increasing the concentration of Fe<sup>3+&nbsp;</sup>from 0.13 to 1.27 at.%&nbsp;comes to increasing photodegradation rate of clopyralid. Results indicate that differences&nbsp;in molecular structure of chosen compound, influence obtained photocatalytic activity to a&nbsp;great extent.</p>
278

Aufbau einer HPLC-UV-ESI-MS/MS-Datenbank und ihre Anwendung im Screening arktischer und antarktischer Meeresbakterien / Assembling of a HPLC-UV-ESI-MS/MS database and its application in the screening of arctic and antarctic sea bacteria

Schuhmann, Imelda 29 June 2005 (has links)
No description available.
279

Desenvolvimento de metodologia para avaliação de resíduos de agrotóxicos em café torrado

Souza, Nicaellen Roberta da Silva 31 July 2015 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Agriculture is one of the main economic activities of the Brazil, possessing the culture of coffee as their main primary commodity. In order to achieve high levels of production and prevent the loss of crops, farm inputs such as pesticides are used in large quantities. This type of practice and the increased public concern consumer are motivating scientific research about these topics, with the aim of ensuring food safety of products supplied for consumption. However, the literature does not report methodologies for the determination of pesticide residues in roasted coffee, with the methods of extraction and analysis proposed, which according to bibliographic data present residues of these substances even after roasting. In this context, the present study sought to develop an analytical methodology to determine carbofuran, cypermethrin, chlorpyrifos, clothianidin, disulfoton, endosulfan, spirodiclofen, haloxyfop, imidacloprid, tebuconazole, triadimenol and triadimefom in roasted coffee using solid liquid extraction method by sonication with clean-up step through liquid liquid extraction (LLE) and instrumental analysis for ultra performance liquid chromatography tandem mass spectrometry detector (LC-MS/MS). For both, the optimization of chromatographic conditions and assessing the best method of clean-up was carried out. With that, the conditions for better quantitative response was obtained with 0.5 g of roasted coffee, 5 mL extraction solvent by sonication, 1 mL of water and 1 mL of dichloromethane in the clean-up by LLE. During the validation procedure in LC-MS/MS positive matrix effect was observed for all analytes except of cypermethrin in which there was suppression of the signal by array, causing, prepared in the curve-based extract, recoveries between 74.2%-102.4% standard relative deviation (SRD) between 0.6% and 10.2%, in levels concentration assessed in the process, Furthermore, the linearity obtained was in the range of 0.9979 to 0.9998 for pesticides , carbofuran, disulfoton, imidacloprid, clothianidin tebuconazole, triadimenol, triadimefom and ensuring the efficiency of the methodology. / A agricultura é uma das principais atividades econômicas do Brasil, possuindo a cultura do café como sua principal commodity primária. A fim de atingir altos níveis de produção e evitar a perda das safras, insumos agrícolas como os agrotóxicos são utilizados em grandes quantidades. Este tipo de prática e o aumento da preocupação do público consumidor estão motivando investigações científicas a respeito destes tópicos, com o intuito de garantir a segurança alimentar dos produtos fornecidos para o consumo. No entanto, a literatura não relata metodologias para a determinação de resíduos de agrotóxicos no café torrado, com os métodos de extração e análise propostos, que segundo dados bibliográficos apresentam resíduos destas substâncias mesmo após a torrefação. Neste contexto, o presente trabalho buscou desenvolver uma metodologia analítica para determinar carbofurano, cipermetrina, clorpirifós, clotianidina, dissulfotom, endosulfan, espirodiclofeno, haloxifope, imidacloprido, tebuconazol, triadimefom e triadimenol em café torrado empregando método de extração sólido líquido por sonicação com etapa de clean-up por meio de extração líquido líquido (LLE) e análise instrumental por cromatografia líquida de ultra eficiência acoplada a detector por espectrometria de massas (LC-MS/MS). Para tanto, a otimização das condições cromatográficas e a avaliação do melhor método de clean-up foram realizadas. Com isso, as condições de melhor resposta quantitativa foi obtida com 0,5 g de café torrado, 5 mL de solvente de extração por sonicação, 1 mL de água e 1 mL de diclorometano na etapa de clean-up por LLE. Durante o procedimento de validação no LC-MS/MS foi observado efeito matriz positivo para todos os analitos com exceção da cipermetrina na qual houve supressão do sinal pela matriz, ocasionando, com base na curva preparada no extrato, recuperações entre 74,2% - 102,4%, com desvio padrão relativo entre 0,6% e 10,2%, nos níveis de concentração avaliados no processo, além disso, a linearidade obtida foi na faixa de 0,9979 a 0,9998 para os agrotóxicos, carbofurano, clotianidina dissulfotom, imidacloprido, tebuconazol, triadimefom e triadimenol, garantindo a eficiência da metodologia.
280

Études des cycles biogéochimiques des contaminants organiques dits « émergents » dans les systèmes aquatiques

Capdeville, Marion-Justine 15 September 2011 (has links)
Les substances pharmaceutiques font partie du groupe des contaminants émergents du fait de leur intérêt récent dans les études environnementales comparativement à des polluants étudiés depuis plus longtemps tels que les pesticides. Elles correspondent aux principes actifs des médicaments et, à ce titre, sont responsables des propriétés pharmacologiques des médicaments. Ce sont donc des molécules biologiquement actives qui peuvent agir sur les organismes vivants présents dans les écosystèmes impactés. L’origine des substances pharmaceutiques dans l’environnement est variable mais les principales sources sont liées à leur utilisation en médecine humaine ou vétérinaire. Une fois consommées, les substances pharmaceutiques sont excrétées dans les urines ou les fèces et se retrouvent dans les eaux usées (consommation humaine) ou dans les déchets d’élevage (consommation vétérinaire). Dans le premier cas, elles peuvent être rejetées directement dans le milieu, ou indirectement, avec les eaux usées traitées ou les boues résiduaires, après traitement dans les stations d’épuration (STEP). Dans le deuxième cas, elles atteignent directement le milieu lorsque les animaux sont élevés en prairie ou indirectement lorsque les déchets d’élevage sont épandus sur les sols agricoles pour les fertiliser. Ces travaux de thèse se sont attachés à étudier l’origine et le devenir de ces substances dans ces 2 cas de figure. Ainsi en se basant sur des critères de consommation, de présence dans l’environnement par rapport à des études antérieures, de toxicité et d’écotoxicité, d’originalité et de disponibilité des composés standards de référence, 32 puis 78 molécules appartenant aux classes thérapeutiques des antibiotiques, des anticancéreux, des béta-bloquants, des anti-VIH et des inhibiteurs de phosphodiestérase de type 5 (PDE 5) ont été étudiées dans 2 continuums : i) effluents hospitaliers - eaux usées brutes et traitées – eaux de surface, et ii) eaux usées brutes et traitées - eaux de surface - eaux de captage souterraines. En s’appuyant sur les mêmes critères de sélection, le devenir de 7 antibiotiques a été étudié dans des lisiers porcins dans des filières simples de traitement du lisier (fosse de stockage), dans des filières complexes de traitement du lisier (système de traitement ressemblant à des mini STEP) et dans des mésocosmes en conditions contrôlées. Pour pouvoir réaliser l’ensemble de ces études, des protocoles analytiques mettant en œuvre une étape d’extraction par SPE (Solide Phase Extraction) ou d’extraction ASE (Extraction Accélérée par Solvant) puis de purification par SPE et d’analyse par LC/MS/MS (Chromatographie en phase liquide couplée à la spectrométrie de masse en tandem) ont été développés. Ces protocoles, en remplissant des critères de qualité tels que des limites de détection et de quantification compatibles avec des analyses environnementales (de l’ordre du ng/l à la dizaine de ng/l), une bonne linéarité, précision, justesse et performance, ont permis d’analyser la phase dissoute des échantillons d’eaux et la phase dissoute et solide des échantillons de lisiers. Il ressort des analyses des échantillons aqueux que : i) les béta-bloquants, les anti-VIH et les antibiotiques appartenant aux familles des macrolides, des fluoroquinolones et des sulfonamides, sont les molécules les plus représentatifs de la contamination du milieu naturel parmi les classes étudiées ; ii) les rejets de STEP sont une source majeure de la contamination des systèmes aquatiques ; iii) les eaux usées sont davantage contaminées en hiver qu’en été ; et iv) les eaux de surface sont davantage contaminées en été qu’en hiver. / Pharmaceutical substances belong to the group of emerging contaminants due to their recent interest in environmental studies in comparison with pollutants who have been studied for a longer time like pesticides. They correspond to the active ingredient of drugs and by this mean are responsible for their pharmacological properties. Consequently they are biologically active molecules that can act on living organisms present in impacted ecosystems. The origin of pharmaceuticals in the environment is variable but the main sources are related to their use in human and veterinary medicine. Once consumed, pharmaceutical substances are excreted in urine or feces and are found in wastewater (human consumption) or animal manure (veterinary consumption). In the first case, they can be discharged directly in the environment, or indirectly, with treated wastewater or sludge from sewage treatment plants (SWTP). In the second case, they directly reach the environment when animals are bred on grassland or indirectly when livestock wastes are spread on agricultural soils as fertilizer. This PhD work has been focused on the study of the origin and fate of pharmaceutical substances in these 2 cases. Thus according to consumption data, occurrence in the environment reported in previous studies, toxicity and ecotoxicity data, originality and availability of reference standard compounds, 32 then 78 molecules belonging to 5 different therapeutic classes (antibiotics, antineoplastics, beta-blockers, anti-HIV, phosphodiesterase type 5 inhibitors (PDE 5 inhibitors)) were studied in 2 continuums : i) hospital wastewater effluents – raw and treated wastewater – surface water, and ii) raw and treated wastewater – surface water – ground water. Based on the same selection criteria, the fate of 7 antibiotics was studied in pig manure in simple manure storage facilities (storage tank), in aerobic manure treatment facilities (treatment system like in small SWTP) and in mesocosms under controlled conditions. In order to achieve all these studies, analytical protocols implementing an extraction step by SPE (Solid Phase Extraction) or an ASE extraction (Accelerated Solvent Extraction) followed by a SPE purification and an analytical step by LC / MS / MS (liquid chromatography tandem mass spectrometry) have been developed. These protocols, by filling out quality criteria such as limits of detection and quantification compatible with environmental analysis (ng/l to dozen of ng/l), good linearity, precision, accuracy and performance, were used to analyze the dissolved phase of water samples and dissolved and solid phases of pig manure samples. The water samples analysis shows : i) beta-blockers, anti-HIV and antibiotic belonging to the families of macrolides, fluoroquinolones and sulfonamides are the most representative molecules of the environmental contamination from the classes studied; ii) SWTP releases are a major source of aquatic systems’ contamination; iii) wastewaters are more contaminated in winter than in summer; and iv) surface water are more contaminated in summer than in winter. The pig manure samples analysis shows : i) the levels of contamination of manure by antibiotics are high, from a few µg/l to mg/l; ii) the manure level of contamination is not related to the physiological stage of pigs; iii) the interest to store manure before spreading in order to reduce the antibiotics contamination is not highlighted; iv) oxytetracycline, tetracycline, tylosin and marbofloxacin are mainly present in the solid phase whereas sulfadiazine, lincomycin and monensin are mainly present in the liquid phase of manure; v) the separation of solid and liquid phases reduce manure contamination in aerobic treatment facilities; and vi) antibiotics degradation is mainly aerobic.Key words: ,

Page generated in 0.0289 seconds