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  • 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.
591

Residual do herbicida 2,4-D no solo e sua correlação com a produtividade e os parâmetros químicos e físicos do solo.

Baumgartner, Denilson 05 July 2013 (has links)
Made available in DSpace on 2017-07-10T19:23:36Z (GMT). No. of bitstreams: 1 Denilson.pdf: 4098476 bytes, checksum: 61dc064a679354a8ec986c07c33444c3 (MD5) Previous issue date: 2013-07-05 / Large amounts of herbicides are used in agriculture to control weeds that pose risks to crops, resulting in increased production cost of farms. Also, if not applied properly, its use can cause resistance of spontaneous plants and result in residues in the environment, in the soil, the water or in toxicity to the crops. The objective of this research was to evaluate the residue of the 2,4-D herbicide in soil and its correlation with yield, as well as physical and chemical properties of the soil. The experiment was conducted on a farm in the city of Nova Santa Rosa, in the state of Paraná in the years 2011 and 2012. The main crops grown in the area are corn and soybeans, in rotation. Soil samples were collected to determine their physical and chemical properties and for analysis of residual 2,4-D before implementation (RI) and after application (RF) of the 2,4-D herbicide. Initially, the glyphosate herbicide was applied in a single dose (2.5 L ha-1) and then the 2,4-D herbicide was applied at two doses (1,0 and 1,5 L ha-1) with boom sprayer and, after 5 days of application, soil samples were collected for analysis of RF. After extracting the 2,4-D from the soil, high performance liquid chromatography (HPLC) was carried out to detect the active ingredient. In order to map the spontaneous plants, before and after spraying the herbicide the method of systematic sampling was used. The soybean yield for both years were also analyzed, and finally, spatial correlation of the parameters evaluated was performed. The results of RI of 2,4-D in the soil in both years, demonstrating that this is a herbicide that can remain retained in the soil over time and, depending on the soil characteristics, the preparation of the area and climatic conditions, this time can be longer. In 2011, the maximum detection of the active ingredient was 609 μg kg-1 and in 2012 was 652 μg kg-1. The RI of 2,4-D in the soil showed negative spatial correlation for chemical attributes K, organic matter and pH and for physical density, macroporosity, microporosity, total porosity and soil moisture it showed positive spatial correlation with sand and the chemical attributes Cu, Mg, Mn, P and Zn in the first year assessed. In 2012 the spatial correlation was positive with clay. The spontaneous plants type horseweed (Conyza bonariensis), did not present spatial correlation among the parameters evaluated in 2011, however, showed a positive correlation with the micropores of the soil in 2012. As residual 2,4-D in the soil and many attributes analyzed presented spatial correlation, spatial correlation among the variables analyzed proved to be an important tool to understand the influence of a parameter over the other. Both doses satisfactorily controlled the incidence of spontaneous plants. The 2,4-D showed some points with detection and other with no detection of the active ingredient in the soil, a fact that demonstrates the importance of assessing the spatial correlation of soil properties (chemical and physical) with residual herbicide in the soil, determining the influence of one attribute over the other. / Grandes quantidades de herbicidas são utilizadas na agricultura para controlar plantas espontâneas que oferecem riscos às plantações, acarretando aumento do custo de produção das propriedades agrícolas. Além disso, se não forem aplicados corretamente podem ocasionar a resistência das plantas espontâneas e resultar em residual no ambiente, quer seja no solo, na água ou na toxidez para as culturas. O objetivo desta pesquisa foi avaliar o residual do herbicida 2,4-D no solo e a sua correlação com a produtividade e os atributos químicos e físicos do solo. O experimento foi desenvolvido em uma propriedade agrícola, do município de Nova Santa Rosa/Paraná nos anos de 2011 e 2012. As principais culturas cultivadas na área são o milho e a soja em sistema de rotação. Foram realizadas amostragens de solo para determinação dos seus atributos químicos e físicos e para análise do residual de 2,4-D antes da aplicação (RI) e após a aplicação (RF) do herbicida 2,4-D. Inicialmente, foi aplicado o herbicida glifosato em dosagem única (2,5 L ha-1) e, em seguida, aplicou-se o herbicida 2,4-D em duas doses (1,0 e 1,5 L ha-1) com pulverizador de arrasto e, após 5 dias da aplicação, amostras de solo foram coletadas para análise do RF de 2,4-D. Após a extração do 2,4-D do solo foi efetuada a determinação por meio de cromatografia líquida de alto desempenho (HPLC) para detecção do ingrediente ativo. Para o mapeamento das plantas espontâneas, antes e após a pulverização do herbicida foi utilizado o método da amostragem sistemática. Também foi avaliada a produtividade da soja para ambos os anos e, por fim, foi efetuada a correlação espacial dos parâmetros avaliados. Os resultados do RI de 2,4-D no solo em ambos os anos, demonstram que este é um herbicida que pode permanecer retido no solo com o passar do tempo e, dependendo das características do solo, do preparo da área e das condições climáticas será maior ou menor. Em 2011, o valor máximo de detecção do ingrediente ativo foi de 609 μg kg-1 e em 2012 foi de 652 μg kg-1. O RI de 2,4-D no solo apresentou correlação espacial negativa para os atributos químicos K, matéria orgânica e pH e para os atributos físicos densidade do solo, macroporosidade, microporosidade, porosidade total e umidade do solo e correlação espacial positiva com a areia e com os atributos químicos Cu, Mg, Mn, P e Zn no primeiro ano avaliado. Já em 2012, a correlação espacial foi positiva com a argila. As plantas espontâneas do tipo buva (Conyza bonariensis) não apresentaram correlação espacial com os parâmetros avaliados em 2011, porém apresentaram correlação positiva com os microporos do solo em 2012. Como residual de 2,4-D no solo e muitos atributos analisados apresentaram dependência espacial, a correlação espacial entre as variáveis analisadas mostrou-se uma ferramenta importante para se conhecer a interferência de um parâmetro sobre o outro. Ambas as doses controlaram de modo satisfatório a incidência de plantas espontâneas. O 2,4-D apresentou alguns pontos com detecção e outros sem detecção do ingrediente ativo no solo, fator que demonstra a importância de avaliar a correlação espacial dos atributos do solo (químicos e físicos) com o residual do herbicida no solo, determinando a influência de um atributo sobre outro.
592

Eelgrass (Zostera marina) Population Decline in Morro Bay, CA: A Meta-Analysis of Herbicide Application in San Luis Obispo County and Morro Bay Watershed

Sinnott, Tyler King 01 December 2020 (has links)
The endemic eelgrass (Zostera marina) community of Morro Bay Estuary, located on the central coast of California, has experienced an estimated decline of 95% in occupied area (reduction of 344 acres to 20 acres) from 2008 to 2017 for reasons that are not yet definitively clear. One possible driver of degradation that has yet to be investigated is the role of herbicides from agricultural fields in the watershed that feeds into the estuary. Thus, the primary research goal of this project was to better understand temporal and spatial trends of herbicide use within the context of San Luis Obispo (SLO) County and Morro Bay Watershed by analyzing data of application by mass, area, and intensity to identify herbicides with the highest potential for local environmental pollution. California Pesticide Use Annual Summary Reports (PUASR) from the years 2000 to 2017 were used to obtain data for conducting a meta-analysis to estimate total herbicide application by weight within every township, range, and section for each of the eight selected herbicides: oxyfluorfen, glyphosate, diuron, chlorthal-dimethyl, simazine, napropamide, trifluralin, and oryzalin. A second goal was to select an analytical laboratory that would be best suited for herbicide analysis of estuary sediments to determine the presence, or lack thereof, of the eight selected herbicides. Criteria of consideration in laboratory selection included herbicides detection capabilities, detection/reporting limits, testing prices, chain of custody protocols, turnaround times, and laboratory site locations. The meta-analysis yielded results showing high herbicide application rates in SLO County with glyphosate, oxyfluorfen, and chlorthal-dimethyl being identified as three herbicides of elevated risk for local environmental contamination due high rates of use by mass, by area, and/or intensity during the study timeframe. Additionally, Morro Bay Watershed exhibited moderate rates of herbicide application with chlorthal-dimethyl and glyphosate being of highest risk for contamination and accumulation within the estuary because of high application rates by mass, by area, and/or intensity. Finally, Environmental Micro Analysis (EMA) and Primus Group, Inc. (PrimusLabs) were identified as the top candidates for analytical laboratory testing of Morro Bay Estuary sediment samples to be obtained and tested for the selected herbicides. These laboratories provide superior analytical capabilities of the eight herbicides, impressive reporting limits or lower detection limits, competitive testing prices for detecting multiple constituents in multiple samples, robust chain of custody protocols, options for quick turnaround times, and laboratory site locations within California.
593

Single and binary effects of atrazine, copper and chromium on duckweed

Nguyen, Vu, Nguyen, Thi Thuy Trang, Vo, Thi My Chi, Dao, ThanhSon 13 May 2020 (has links)
Recently, the agricultural, industrial and mining activities have led to increase in contaminant emission. Trace metals or herbicides are among the pollutants to be concerned in the world. In this study we evaluated the effects of the herbicide atrazine (at the concentrations of 5, 50 and500 µg L-1) and its combination with copper (Cu, 50 µg L-1) and chromium (Cr, 50 µg L-1) on duckweed over the period of 10 days in the laboratory conditions. We found that 50 and 500 µg atrazine L-1 severely impacted on the growth or even caused the death of the plants, whereas there was no statistically significant difference in the duckweed growth rate between the 5 µg atrazine L-1 exposure and control. In the combined treatments (50 µg atrazine L-1 with Cu; with Cr or with both Cu and Cr), the plant growth rate of atrazine with either Cu or Cr was strongly reduced. However, the mixture of atrazine with Cu and Cr did not significantly decrease the development and growth rate of duckweed. Besides, atrazine and investigated heavy metals resulted in turning whiteof duckweek leaves that evidence ofthe chlorophyll degradation. Our results showed the negative influences of the herbicide atrazine and metals on development and morphology of duckweed. / Gần đây, những hoạt động nông nghiệp, công nghiệp và khai khoáng đã và đang dẫn đến sự gia tăng phát thải các chất gây ô nhiễm. Kim loại nặng hoặc thuốc diệt cỏ là những chất gây ô nhiễm đang được quan tâm trên thế giới. Trong nghiên cứu này, chúng tôi đánh giá ảnh hưởng của thuốc diệt cỏ atrazine (nồng độ 5, 50 và 500 µg/L) và sự kết hợp của chất này với đồng (Cu, 50 µg/L) và crom (Cr, 50 µg/L) lên bèo tấm trong thời gian 10 ngày trongđiều kiện phòng thí nghiệm. Chúng tôi nhận thấy atrazine tại nồng độ 50 và 500 µg/L đã gây nên những ảnh hưởng nghiêm trọng lên sự phát triển hay thậm chí làm cho bèo tấm bị chết, trong khi đó, không ghi nhận được bất kì sự khác biệt có ý nghĩa thống kê về tốc độ tăng trưởng của bèo tấm giữa lô thí nghiệm phơi nhiễm 5 µg atrazine / L và lô đối chứng. Trong những lô phơi nhiễm kết hợp (50 µg atrazine / L với Cu, với Cr hoặc với đồng thời Cu và Cr), tốc độ tăng trưởng của bèo tấm khi phơi nhiễm với atrazine và Cu hoặc Cr bị giảm mạnh, tuy nhiên, việc phơi nhiễm đồng thời atrazine với Cu và Cr đã không làm giảm đáng kể sự phát triển và tốc độ tăng trưởng của bèo tấm. Bên cạnh đó, atrazine và kim loại nặng đã làm cho màu của lá bèo tấm chuyển sang màu trắng, điều này chứng tỏ có sự suy giảm chlorophyll. Kết quả nghiên cứu này đã cho thấy những ảnh hưởng tiêu cựccủa thuốc diệt cỏ atrazine và kim loại lên sự phát triển và hình thái của bèo tấm.
594

Biomineralization of atrazine and analysis of 16S rRNA and catabolic genes of atrazine-degraders in a former pesticide mixing and machinery washing area at a farm site and in a constructed wetland

Douglass, James F. January 2015 (has links)
No description available.
595

Characterization and Management of Glyphosate-Resistant Giant Ragweed (<i>Ambrosia trifida</i>(L.) and Horseweed [<i>Conyza canadensis</i> (L.) Cronq.]

Stachler, Jeff Michael 29 July 2008 (has links)
No description available.
596

Destination of Isotopic Nitrogen Fertilizer Under Varying Herbicide Regimes in a Mid-Rotation Loblolly Pine (Pinus taeda L.) Plantation in the Piedmont of Virginia, USA

Van-Spanje, Megan 24 May 2023 (has links)
Mid-rotation fertilization and vegetation control are some of the most common silvicultural treatments in loblolly pine (Pinus taeda L.) plantations in the southeastern United States. Competing vegetation is commonly thought to sequester fertilizer nitrogen (N) and reduce the potential growth response to a mid-rotation fertilization treatment. This experiment aims to identify what proportion of applied N fertilizer is retained in the crop tree pine foliage, and the degree to which understory vegetation is competing for this resource. Our mid-rotation loblolly pine plantation received an application of 15N fertilization (urea 365 kg/ha, at 46% N by weight, i.e. 168 kg/ha of N) and a portion of plots received an understory vegetation control (basal spray application of triclopyr; 13.6% active ingredient) treatment either before fertilization or not at all. One-year post-fertilization, 15N contents within pine foliage, leaf fall/leaf litter, forest floor, and soil were measured, as was competing vegetation presence. There was significant variation in applied nitrogen acquisition among the different ecosystem components measured, with 0-15 cm soils retaining a majority at 32-37% added 15N. Differences in fertilizer N acquisition in pine foliage between plots with and without understory vegetation control was marginally significant (p = 0.06) with pine foliage in plots without understory vegetation capturing greater 15N (4.3% greater). Red maple (Acer rubrum) and oak species (Quercus spp.) were the most common competitors but neither had a uniquely pronounced effect on pine nitrogen sequestration. My data indicate that increasing competition reduces fertilizer N foliar concentrations in crop pine trees but at a modest rate and equally across species groups. An unrefined threshold determining when fertilizer N capture in crop pine trees was affected was found at 3.1 m2/ha of competing vegetation basal area. This site will continue to be monitored over time to assess fertilizer N retention in loblolly pine each year after fertilization and evaluate the fertilizer N capture within competing vegetation. / Master of Science / Some of the most prevalent management practices for mid-rotation (age 15, i.e., roughly halfway through a crop cycle) loblolly pine (Pinus taeda L.) plantations in the southeastern United States are fertilization and vegetation control. Nitrogen (N) is consistently one of the most limiting factors to productivity. The addition of N via fertilization is therefore a common forestry practice. However, when a stand is fertilized, the added resource is partitioned and cycled throughout the ecosystem. It is presumed that the amount of fertilizer N obtained by crop trees in a plantation is dependent on the level of competing vegetation (i.e., weed-trees and shrubs) present on site. Controlling competing vegetation prior to fertilization may therefore be warranted under certain conditions. To date, the amount of competing vegetation where it begins to impact fertilizer uptake by the crop tree is unknown. This study aims to elucidate this competing vegetation threshold to better inform mid-rotation management of loblolly pine plantations. This study examined applied fertilizer N capture in ecosystem components with varying levels of understory vegetation, and found more fertilizer N in pine foliage when understory vegetation was completely removed prior to fertilization. No single understory hardwood weed species had a uniquely strong influence on crop tree productivity uptake. Plots that ranked in the upper third in competing vegetation presence did have significantly less foliar fertilizer N in the pine crop trees. Additional replication of this study would be necessary to determine a universal threshold of competing vegetation which would trigger the removal of competing vegetation prior to fertilization.
597

Das Problem der Welternährung: Simulationen zu Einflussfaktoren, die Bedeutung von Agrartechnologien und gesellschaftliche Einschätzungen in Deutschland / The Problem of World Food Security: Simulations on Influencing Factors, the Impact of Agricultural Technologies, and Public Opinion in Germany

Klümper, Wilhelm 13 November 2014 (has links)
Hunger ist nach wie vor ein weit verbreitetes Problem. Nach der jüngsten Schätzung der FAO hungern weltweit noch immer über 800 Mio. Menschen. Prognosen gehen davon aus, dass die Agrarproduktion bis 2050 verdoppelt werden muss, um der steigenden Nachfrage nach Agrarprodukten durch Bevölkerungswachstum, Bioenergieproduktion und sich verändernde Ernährungsgewohnheiten zu begegnen. Unter vielen Möglichkeiten, das Welternährungsproblem zu beschreiben, wird in dieser Dissertation das Konzept der Ernährungssicherheit nach der Definition der FAO herangezogen. Ernährungssicherheit umfasst als wichtigste Aspekte die Verfügbarkeit von Nahrungsmitteln und den ökonomischen Zugang zu Nahrungsmitteln. Nahrungsmittelverfügbarkeit ist in erster Linie von einer global ausreichenden Produktion abhängig, der Zugang zu Nahrung von der Kaufkraft der Haushalte. Die Kaufkraft wird sowohl durch das Einkommen wie auch die Agrarpreise beeinflusst. Die Nahrungsmittelverfügbarkeit kann vor allem durch Ertragssteigerungen erhöht werden. Sollen die Ertragssteigerungen ressourcenschonend erfolgen, muss die Produktivität der Agrarproduktion bezogen auf alle Produktionsfaktoren inkl. Umweltgütern steigen. Nur durch technische und organisatorische Innovation kann dies realisiert werden. Ertragssteigerungen in Entwicklungsländern erhöhen gleichzeitig die Einkommen von potenziell von Hunger Betroffenen. Eine Begrenzung der Nachfrage nach Agrargütern kann global in erster Linie in den Bereichen Bioenergie und Konsum tierischer Produkte erfolgen. Simulationen können helfen, den Einfluss einzelner Faktoren der globalen Nachfrage und des Angebots nach Agrarrohstoffen und -produkten auf die Welternährungslage genauer abzuschätzen. Ein Großteil der Simulationen in der Literatur kommt mithilfe von partiellen oder allgemeinen Gleichgewichtsmodellen zu Aussagen über gehandelte Mengen und Preise oder Wohlfahrtseffekte. In dieser Arbeit wird ein einfaches partielles Gleichgewichtsmodell für den Weltmarkt für Biotreibstoffe, Fleisch und Getreide entwickelt und mit der Methode der FAO zur Schätzung der Zahl der Hungernden gekoppelt. Dies ermöglicht die Abschätzung des Einflusses verschiedener Szenarien auf die Zahl der Hungernden. Für das Referenzjahr 2011 werden Szenarien alternativer Nachfrage nach Fleisch und Biotreibstoffen simuliert, ebenso wie ein Szenario alternativer landwirtschaftlicher Produktivität in der Europäischen Union. Die Schätzungen ergeben einen signifikanten Einfluss der simulierten Nachfrage- und Angebotsverschiebungen. Im Vergleich mit dem Status Quo führt eine Reduktion des Fleischkonsums in den OECD-Ländern um 50% zu einer Reduktion der Zahl der Hungernden um 5%. Eine ii Flächenproduktivität im Getreideanbau in der EU auf dem Niveau von 1980 steigert die Zahl der Hungernden um mehr als 5%, ein Anstieg der Biotreibstoffquote in der OECD auf 10% erhöht die Zahl der Hungernden gar um 10%. Die Durchsetzung geeigneter politischer Maßnahmen zur Verbesserung der Welternährungslage kann durch eine breite öffentliche Unterstützung beschleunigt oder erst ermöglicht werden. Über die öffentliche Meinung zu Fragen der Welternährung in Deutschland existieren bisher keine expliziten Studien. In den Themenbereichen landwirtschaftliche Produktion und Nahrungsmittelkonsum stellt das Thema Welternährung nur einen Aspekt dar, der neben Fragen nach z.B. der Lebensmittelsicherheit und Gesundheit sowie den Auswirkungen von Agrarproduktion auf Landschaft und Umwelt steht. Hier werden Ergebnisse einer Online-Befragung zum Thema Welternährung präsentiert, die im März 2012 mit einer repräsentativen Stichprobe 1.200 deutscher Internetnutzer durchgeführt wurde. Die Befragung beinhaltete im Wesentlichen die Bewertung der Wirkung verschiedener potenzieller Ursachen der weltweiten Unterernährung, sowie Maßnahmen und Entwicklungen zu ihrer Lösung. Die Ergebnisse zeigen, dass das Thema Welthunger in erster Linie mit Merkmalen akuter (Hunger-) Krisen in Verbindung gebracht wird. Die vielversprechendsten Lösungsmaßnahmen sind in den Augen der Befragten der Ausbau des Fairen Handels, Absatzmärkte für Kleinbauern sowie ein Lebensmittelspekulationsverbot. Der intensiven Landwirtschaft in der Welt wie auch in Europa sowie insbesondere der Grünen Gentechnik wird kein Potenzial zur Lösung des Problems zugesprochen. Die Antwortmuster lassen auf die Präsenz eines Halo-Effekts mit einer Übertragung unterstellter negativer Umweltwirkungen auf das Thema Welternährung schließen. Die Grüne Gentechnik ist eine Agrartechnologie, die potenziell zur Angebotsausweitung von Agrarprodukten genauso beitragen kann wie zu einer ressourcenschonenderen Landwirtschaft. Bisherige Anwendungen, hauptsächlich Herbizidtoleranz sowie Insektenresistenz, haben u.a. zu einer Steigerung der effektiven Erträge, einer Einsparung von Insektiziden und einer Steigerung der Profite vor allem im Baumwollanbau beigetragen. Trotz zahlreicher Belege besteht über die Auswirkungen von gentechnisch veränderten (GV) Nutzpflanzen eine anhaltende Kontroverse. Ein Großteil der europäischen Bevölkerung lehnt den Anbau ebenso ab wie einen Verzehr von Produkten aus GV-Pflanzen. Unterstellte sozio-ökonomische Auswirkungen oder Auswirkungen auf die Welternährung sind nur zwei Determinanten von vielen, die zu den Einstellungen zur Grünen Gentechnik beitragen. Zur Konsolidierung des Wissens im Bereich agronomischer sowie sozio-ökonomischer Auswirkungen von GV-Pflanzen wurde eine Meta-Analyse durchgeführt. In wissenschaftlichen Datenbanken wurden iii 147 Primärstudien identifiziert, die für die Meta-Analyse verwendet wurden. Die Analyse beschränkt sich auf gentechnisch veränderte Sojabohnen, Mais und Baumwolle. Als mittlere Effekte des Anbaus von GV-Pflanzen ergibt die Meta-Analyse eine Steigerung des Ertrages um 22%, eine Reduktion der Menge der angewendeten Pflanzenschutzmittel um 37% und eine Steigerung der Profite der Bauern um 68%. Die Höhe der Effekte hängt stark von verschiedenen Faktoren ab. Die Effekte sind für alle drei genannten Variablen in Entwicklungsländern betragsmäßig größer als in Industrieländern. Auch sind die Effekte des Anbaus von GV-Pflanzen bei Erträgen und beim Pflanzenschutzmitteleinsatz betragsmäßig höher für insektenresistente Pflanzen als bei solchen mit Herbizidtoleranz. Aus den in der Arbeit gewonnenen Erkenntnissen kann geschlussfolgert werden, dass sowohl das Nahrungsmittelangebot gesteigert als auch die Nachfrage begrenzt werden sollte. Dies verlangt eine standortangepasste Ausnutzung vorhandener und die Entwicklung neuer Technologien. Auch die Gentechnik kann einen Beitrag leisten. Der Kleinbauernsektor muss vordringlich gefördert werden. Zur Begrenzung der Nachfrage können neben der Politik, welche vor allem die Biotreibstoffnachfrage beeinflussen kann, auch Konsumenten durch Verzicht auf tierische Produkte beitragen. Dies wie auch die Durchführung effektiver politischer Maßnahmen sind auf eine unverzerrte Sichtweise der Öffentlichkeit auf das Thema Welternährung angewiesen. Dazu muss das Thema in Wissenschaftskommunikation und Bildung stärker thematisiert werden.
598

Biosensors for Environmental Monitoring and Biomedical Applications / Biosensors for Environmental Monitoring and Biomedical Applications

ŠTOFIK, Marcel January 2012 (has links)
Study of biosensors has become an essential part of research in biotechnology. Biosensors as fast, portable, highly sensitive, and low-cost bioanalytical detection devices have been utilized in many fields of human activity. The first part of the presented work focuses on electrochemical biosensors for rapid environmental screening of herbicides as water pollutants. A sol-gel immobilization method for a photosystem II (PSII) complex is studied in order to enhance the sensitivity and the signal strength and stability of a PSII-based biosensor. Computer simulations of a PSII biosensor are employed with the aim to find out how the immobilization membrane properties influence the biosensor parameters. Newly developed immobilization by a thin-layer membrane based on the results of computer simulations and revised measurement protocols are presented. The second part of the work is devoted to synthesis and electrochemical detection of newly developed metal labels for electrochemical immunosensors. The synthesis of dendrimer-encapsulated silver nanoparticles and biorecognition properties of biotin-nanocomposite conjugates are discussed. For detection of synthesized labels, a microfluidic detector was manufactured and tested and different approaches to packing of a microfluidic chip employing polydimethylsiloxane (PDMS) were investigated. Newly designed microstructures for a microfluidic separator of magnetic beads (MBs) were studied by computer simulations. The separator was made and trapping of MBs for the further employment in MBs-based immunoassays are presented
599

Avaliação genotóxica e mutagênica de herbicidas em organismos aquáticos / Genotoxic and mutagenic evaluation of herbicides in aquatic organisms

Carvalho, Wanessa Fernandes 23 March 2018 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-05-03T13:16:12Z No. of bitstreams: 2 Tese - Wanessa Fernandes Carvalho - 2018.pdf: 4178094 bytes, checksum: 12ab926257d567aaefec72a5d4d53bf7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-05-03T13:23:49Z (GMT) No. of bitstreams: 2 Tese - Wanessa Fernandes Carvalho - 2018.pdf: 4178094 bytes, checksum: 12ab926257d567aaefec72a5d4d53bf7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-05-03T13:23:49Z (GMT). No. of bitstreams: 2 Tese - Wanessa Fernandes Carvalho - 2018.pdf: 4178094 bytes, checksum: 12ab926257d567aaefec72a5d4d53bf7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The increased use of pesticides, the risks and disruptions that these compounds can cause to organisms and the environment has been much discussed in recent years. 2,4-D and glyphosate herbicides are applied post-emergence in large-scale crops and play an important role in the optimization of agricultural production worldwide. Environmental quality bioindicators are used in environmental impact assessment studies because of their interaction with the environment and their ease of absorption and accumulation of xenobiotic compounds (Younes, 2000). Therefore, the objective of this study was to evaluate the genotoxic and mutagenic effects of herbicides on environmental quality bionicators. Acute toxicity of Credit® at 48%, Herbifen Super® at 97%, Weedar Full® at 83.5%, Dedalo elite® at 30%, and Imazethapyr and their binary combinations were tested on Cnesterodon decemmaculatus, Rhinella arenarum and Dendropsophus minutus. The lethal effect was determined from experiments with mortality and the sublethal was used the single cell gel electrophoresis (SCGE) bioassay and the micronucleus test. The LC5096h value for Herbifen Super® was 2.668 mg / L, Weedar Full® was 678.04 mg / L, Dedalo elite® was 0.463 mg / L and for Credit® was 91.73 mg / L and Imazethapyr® was 0.99 mg / L. The results of this study demonstrated that the comet assay and the micronucleus test are highly sensitive methods for the detection of herbicide-induced DNA damage in aquatic organisms. The herbicides tested showed different behaviors when combined at their concentrations of 5% and 10% of LC5096h. The toxic effect of the combination of Herbifen Super® and Credit® was basically due to the action of the active principle glyphosate present in Credit®. For Weedar Full® and Dedalo elite® herbicides, synergism was observed in combinations of 5% and 10% of LC5096h values. Our study is the first report on the induction of lethal acute and sublethal effects of Credit® binary combinations; Herbifen Super®, Weedar Full®, Dedalo elite®; Imazethapyr® in aquatic organisms. / O aumento da utilização dos pesticidas, os riscos e perturbações que esses compostos podem provocar aos organismos e ao meio ambiente está sendo bastante discutido nos últimos anos. Os herbicidas 2,4-D e glifosato são aplicados em pós-emergência em culturas de larga escala e desempenham um papel importante na otimização da produção agrícola em todo o mundo. Os bioindicadores de qualidade ambiental são utilizados em estudos de avaliações de impacto ambiental devido sua interação com o meio ambiente e a sua facilidade de absorção e acumulação de compostos xenobióticos (Younes, 2000). Sendo assim, o objetivo deste estudo foi avaliar os efeitos genotóxicos e mutagênicos de herbicidas em biondicadores de qualidade ambiental. A toxicidade aguda do Credit® a 48%, Herbifen Super® a 97%, Weedar Full® a 83.5%, Dedalo elite® a 30% e Imazethapyr e suas combinações binárias foram testadas em Cnesterodon decemmaculatus, Rhinella arenarum e Dendropsophus minutus. O efeito letal foi determinado a partir de experiências com mortalidade e o subletal foi utilizado o bioensaio de eletroforese em gel de célula única (SCGE) e oteste do micronúcleo. O valor LC5096h para Herbifen Super® foi de 2.668 mg / L, Weedar Full® foi de 678,04 mg/L, Dedalo elite® foi de 0,463 mg/L e para Credit® foi de 91.73 mg /L e Imazethapyr® foi de 0.99 mg/L. Os resultados deste estudo demontraram que o ensaio cometa e o teste do micronúcleo são métodos altamente sensíveis para a detecção de danos ao DNA induzidos por herbicidas em organismos aquáticos. Os herbicidas testados revelaram diferentes comportamentos ao serem combinados em suas concentrações de 5% e 10% da CL5096h. O efeito tóxico da combinação entre Herbifen Super® e Credit® deu-se basicamente pela ação do princípio ativo glifosato presente no Credit®. Para os herbicidas Weedar Full® e Dedalo elite® foi observado um sinergismo nas combinações de 5% e 10% dos valores de CL5096h. Nosso estudo constitui o primeiro relatório sobre a indução de efeitos agudos letais e subletal de combinações binárias de Credit® ; Herbifen Super® , Weedar Full® , Dedalo elite® ; Imazethapyr® em organismos aquáticos.
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Effekter av en toxisk cocktail av Roundup och livsmedelsklassad polypropylenplast på vattenloppan Daphnia Magna

Ardenstedt, Jonathan, Fridefors, Patricia January 2023 (has links)
Gifter och föroreningar förekommer sällan ensamma och studier om olika toxiska substanser genomförs ofta med endast en substans i taget. Det finns studier som har undersökt exempel på olika cocktails av substanser, men ibland är det svårt att identifiera alla källor som påverkar en organism. Vi har undersökt hur en kombination av ogräsmedlet Roundup och livsmedelsklassad polypropylenplast påverkar det sötvattenlevande kräftdjuret Daphnia magna. Vi fann att i högre doser orsakar Roundup 100% dödlighet innan könsmognad, men att det i små doser inte resulterar i lägre fitness än kontrollgruppen, utan till och med ökade den initiala överlevnaden när den tillsattes i plastbrukar. En cocktail av Roundup och plast orsakade en fördubblad utvecklingstid för äggen. Ägg från individer i plastburkar hade också en längre utvecklingstid men dessa individer hade även ett mycket högre antal ägg. Framtida studier bör undersöka avkommans fitness. Tidigt i studien upptäckte vi att det med stor sannolikhet fanns en tredje faktor som påverkade daphnierna negativt, som inte kunde förklaras av Roundup eller plastburkar, men som vi inte kunde identifiera. Därför vill vi också framhäva att experiment lätt kan påverkas av okända faktorer. / Toxins and pollutants rarely come alone and studies about various toxic substances are often performed with only one substance at a time. There are studies that have examined different cocktails of substances, but sometimes it can be difficult to identify all sources that affect an organism. We have investigated how a combination of the herbicide Roundup and Food Safe polypropylene plastic affect the freshwater crustacean Daphnia magna. We found that Roundup causes 100% mortality before reaching fertility in higher doses, but that in small doses does not result in lower fitness compared to the control group, but even increases the initial survival rate when Roundup is added to plastic jars. A cocktail of Roundup and plastic resulted in a doubled development time for the eggs. Eggs from individuals in plastic jars also had a longer development time but there was also a much higher number of eggs from these individuals. Futiure studies ought to investigate the fitness of the offspring. Early in the study we discovered that there was most likely a third factor influencing the daphnia negatively, that could not be explained by plastic jars or Roundup, but one that we could not identify. Therefore, we also wish to urge that experiments can easily be influenced by unknown factors.

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