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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.
51

Effects Of Acrylamide And Resveratrol On Rabbit Liver And Kidney Antioxidant Enzymes

Kalin, Cigdem 01 January 2010 (has links) (PDF)
Resveratrol is one of the promising naturally occurring polyphenolic compound found in red wine having antioxidant and anti-carcinogenic properties. However, in vivo studies investigating the effects of resveratrol on antioxidant enzymes are limited. In the present study, we investigated, for the first time, the influence of resveratrol on liver and kidney antioxidant enzymes and oxidative stress markers in acrylamide treated and control rabbits. New Zealand male rabbits were treated with acrylamide and resveratrol, separately in two different doses and conditions. Their combined effects were also investigated. While, acrylamide treatment significantly decreased the glutathione peroxidase (GPx) activity in liver (1.24-fold), it was significantly increased (1.20 &ndash / 1.40-fold) by combined effect of resveratrol and acrylamide in liver and kidney. Furthermore, alone resveratrol administration increased (~1.37 &ndash / fold) GPx activity in kidney. Although, glutathione reductase (GR) was found to be significantly increased (~1.30-fold) in two different dose of resveratrol treated rabbit liver, it was not changed in acrylamide and their combined treatments. Despite, glutathione (GSH) content was decreased around 1.6 fold as a result of acrylamide treatment in rabbit liver and kidney cytosols, GSH level was returned to normal levels by resveratrol tretment in rabbit liver and kidney. Furthermore, acrylamide treatment significantly increased the SDH activity in blood serum (1.68-fold) and in liver (1.27-fold) with respect to control. On the other hand, resveratrol treatment brought this activity nearly normal level in acrylamide treated rabbits.. Besides, sorbitol deydrogenase (SDH) was found to be decreased (3.13-fold) significantly in rabbit liver cytosol as a result of single dose of 100 mg/kg b.w. resveratrol treatment. Moreover, catalase activity and MDA level were not affected from either resveratrol or acrylamide and with their combination effect in investigated rabbit organs. An important liver damage marker enzyme other than ALT and AST, SDH was characterized in terms of substrate, cofactor and enzyme concentration in rabbits which have been not investigated before and found to be 200 mM, 141 &micro / M and 0.5 &micro / L, respectively in rabbit liver. Furthermore, the Km value was first calculated in liver of New Zealand rabbits as 55,5 mM. In addition to these, in vitro effects of resveratrol on GST activity was also studied throughout this study. Resveratrol was shown to be a noncompetitive inhibitor for liver cytosolic GST against substrate CDNB with Ki of 175 &micro / M. On the other hand, resveratrol was shown to be a competitive inhibitor for liver cytosolic GST against substrate GSH with Ki of 55 &micro / M. The results of the present study have demonstrated for the first time that resveratrol induced some of the antioxidant enzyme activities and as well nonenzymatic antioxidants in rabbit liver and kidney. The results of GPx, GR, SDH activities and GSH level have also suggested that resveratrol may have protective effects on acrylamide induced hepatoxicity and renal toxicity. Therefore, it may be a therapeutic approach for the oxidative stress-related diseases such as cancer. However, further in vivo studies are required to clarify the effect of resveratrol on both acrylamide-induced toxicity and bioavailability in the body.
52

Synthesis And Characterization Of Hydrogels From Allyl Methacrylate And Acrylamide Copolymer

Ayazoglu, Neslihan 01 February 2011 (has links) (PDF)
Acrylamide based hydrogels were synthesized through copolymerization reaction of allyl methacrylate with acrylamide. Copolymerization reactions were carried out with solution polymerization in tetrahydrofuran by using &alpha / -&alpha / -azoisobutyronitrile as an initiator at 60 0 C. Three copolymer compositions were studied having 5, 15, 25 molar percentage of allyl methacrylate as feed concentrations. The synthesized copolymers were characterized by FTIR, NMR, DSC, TGA and GPC. 1H-NMR spectra were used to confirm the chemical structures of the copolymers and to determine the comonomer compositions of the copolymers. DSC and TGA analysis were conducted to determine the thermal properties of the copolymers and TGA results showed that copolymers have two step degradation behavior. Molecular weights of the copolymers were determined by GPC. Swelling capacities of the obtained hydrogels were investigated and swelling capacity of the gels reached to 77% as maximum value.
53

Structural modification of poly(n-isopropylacrylamide) for drug delivery applications

Chang, Kai 16 September 2013 (has links)
Polymeric biomaterials have become ubiquitous in modern medical devices. ‘Smart’ materials, materials that respond to external stimuli, have been of particular interest for biomedical applications such as drug delivery. Poly(n-isopropylacrylamide) (pNIPAAm) is the best studied thermally responsive, biocompatible, ‘smart’ polymer and has been integrated into many potential drug delivery devices; however, the architectural design of the polymer in these devices is often overlooked. My research focus was the exploration of pNIPAAm architecture for biological applications. Two new biomaterials were synthesized as a result. Architectural modification of linear pNIPAAm was used to synthesize a well-defined homopolymer pNIPAAm with a sharp transition slightly above normal body temperature under isotonic conditions. This polymer required a combination of polymerization and control techniques including controlled radical polymerization, hydrogen bond induced tacticity, and end-group manipulation. The synthesis of this polymer opened up a variety of biomedical possibilities, one of which is the use of these polymers in a novel hydrogel system. Through the use of the controlled linear pNIPAAm synthesized through chain architectural modification, hydrogels with physiological transition temperatures were also synthesized. These hydrogels showed greater shrinking properties than traditional hydrogels synthesized in the same manner and showed physiological mechanical properties. Highly branched pNIPAAm was also optimized for biological applications. In this case, the branching reduced the efficacy of end-groups in transition temperature modification but increased the efficacy of certain copolymers. The resulting biomaterial was incorporated into a nanoparticle drug delivery system. By combining gold nanoparticles with highly branched pNIPAAm, which was designed to entrap small molecule drugs, a hybrid system was synthesized where heating of the nanoparticle through surface plasmon resonance can trigger drug release from the pNIPAAm. This system proved to be easy to synthesize, effective in loading, and controlled in release. As shown from the applications, architectural control of pNIPAAm can open up new possibilities with this polymer for biomedical applications. Small structural changes can lead to significant changes in the bulk properties of the polymer and should be considered in future pNIPAAm based medical devices.
54

Pienarūgščių bakterijų įtaka akrilamido formavimuisi pusruginės duonos gaminiuose bei kvietinių kepinių kokybės pagerinimo galimybės deaktyvuotų mielių priedu / Acrylamide reduction in mixed wheat-rye bread by using lactic acid fermentation and wheat baking quality improvement by using deactivated yeast RS 190

Rekštytė, Toma 18 June 2013 (has links)
Darbo tikslas – įvertinti pienarūgščių bakterijų įtaką akrilamido formavimuisi pusruginės duonos gaminiuose, kurių gamybai naudotos skirtingos PRB (Lactobacillus delbruecki, Pediococcus acidilactici, Pediococcus pentosaceus ir Lactobacillus sakei), bei įvertinti RS 190 deaktyvuotų mielių įtaką kvietinių miltų technologinėms savybėms ir kvietinių kepinių kokybei. Nustatyta, kad akrilamido kiekis kepiniuose kito nuo 37,87 ± 0,55 iki 74,64 ± 0,36 µg/kg. Pusruginės duonos kepiniuose, fermentuotose L. delbruecki nustatytas mažiausias akrilamido kiekis, lyginant su kitais pusruginės duonos kepiniais, kurių gamyboje buvo naudotos PRB. PRB proteolitinis aktyvumas yra tiesiogiai susijęs su akrilamido kiekio mažinimu duonos kepiniuose. Kepiniuose, pagamintuose su L. delbruecki (su didžiausiu proteolitiniu aktyvumu) susidarė mažiausias akrilamido kiekis (37,87 ± 0,55 µg/kg), o kepiniuose fermentuotuose P. pentosaceus ir P. acidilactici (su mažiausiu proteolitiniu aktyvumu) nustatytas didžiausias akrilamido kiekis, atitinkamai, 74,64 ± 0,36 ir 63,38 ± 0,98 µg/kg. Atlikus kvietinių miltų su deaktyvuotų mielių priedu ir be priedo farinografinį tyrimą, nustatyta, kad didžiausiu vandens įgėrimu (59,1 ± 1,18 %) ir tešlos stabilumu (5 kartus didesnis) pasižymėjo kvietiniai miltai su priedu, tačiau jų tešlos susidarymo trukmė 1,3 karto ilgesnė. Deaktyvuotų mielių priedas turi teigiamos įtakos kepinių savitajam tūriui, minkštimo akytumui ir drėgniui. Pagal gautus tyrimo rezultatus galima... [toliau žr. visą tekstą] / The aim of this study was to investigate acrylamide formation in semi rye bread fermented with Lactobacillus delbruecki, Pediococcus acidilactici, Pediococcus pentosaceus and Lactobacillus sakei, and, to investigate the influence of RS 190 deactivated yeast on wheat flour technological properties and wheat bread quality. Results show that the amount of acrylamide in bread samples ranged from 37.87 ± 0.55 to 74.64 ± 0.36 µg/kg. Lactofermentation reduce acrylamide formation in semi rye bread. L. delbruecki was found to have a higher effect on acrylamide reduction in bread samples in compare with P. acidilactici, P. pentosaceus and L. sakei. Also, proteolytic activity of LAB have a influence on acrylamide content reduction in bread. Bread made with L. delbruecki (the highest proteolytic activity) contained lower acrylamide content (37.87 ± 0.55 µg/kg), while breads prepared with P. pentosaceus and P. acidilactici (lower proteolytic activity) contained higher acrylamide contents (74.64 ± 0.36 and 63.38 ± 0.98 µg/kg, respectively). Pharinographic analysis of wheat flour with deactivated yeast and without deactivated yeast results shows that the higher water absorbtion have wheat flour with deactivated yeast (59.1 ± 1.18 %) and higher dough stability (5 times higher) but longer dough formation time (1,3 times longer). The addition of deactivated yeast in wheat flour have a significant effect of bread specific volume, porosity and moisture content. In conclusion we could say... [to full text]
55

Biokatalizatorių įtaka akrilamido formavimuisi ruginės duonos gaminiuose bei kvietinių miltų technologinių savybių pagerinimo galimybės RS 190 modifikuotomis mielėmis, taikant pastaruosius pusruginės duonos gamybai / Impact of biocatalysts on the formation of acrylamide in rye bread products and improvement possibilities of technological properties of wheat flour by genetically modified yeast RS 190 by applying the latter for semi-rye bread making

Krunglevičiūtė, Vita 18 June 2013 (has links)
Darbo tikslas buvo įvertinti biokatalizatorių įtaką akrilamido formavimuisi ruginės duonos gaminiuose bei RS 190 modifikuotų mielių įtaką kvietinių miltų 550 C tipo technologinių savybių pagerinimui, pritaikant juos pusruginės duonos gamybai. Nustatyta, kad L. delbruecki intensyviau mažina terpės pH (3,35) nei P. acidilactici (4,32), tačiau, žaliavos apcukrinimui naudojant gliukoamilolitinius fermentus, fermentacijos procesą galima suintensyvinti. Žaliavos apcukrinimas fermentais įtakoja didesnį P. acidilactici proteolitinių fermentų aktyvumą rauguose. L. delbruecki fermentuoti kepiniai gaunami geresnės kokybės nei fermentuoti P. acidilactici. P. acidilactici fermentuotų kepinių kokybę galima pagerinti naudojant optimalų gliukoamilazės kiekį (0,05 ml). 0,030 ml gliukoamilazės panaudojimas žaliavos apcukrinimui, lėtina kepinių žiedėjimą (minkštimo struktūra pakito: su 0,03 ml – 2,15, su 0,05 ml – 2,54 karto). Akrilamido formavimuisi turi įtakos ne tik fermentacijai naudotos PRB, bet ir kepinio dydis (500 g kepiniuose vidutinis akrilamido kiekis 61,55 µ/kg, 1000 g - 40,48 µ/kg). Tirtų kvietinių miltų fizikinės struktūrinės savybės yra tinkamos mielinių kepinių gamybai, o modifikuotų mielių priedas yra tinkama priemonė kvietinių kepinių kokybės rodikliams pagerinti. 550 C tipo kvietinius miltus su modifikuotų mielių priedu panaudojus pusruginių kepinių gamybai galima pagerinti kepinių akytumą ir padidinti drėgnį, tačiau, kitos savybės nepakinta, arba gaunamos prastesnės. Šis... [toliau žr. visą tekstą] / The goal of the thesis was to assess the impact of biocatalysts on the formation of acrylamide in rye bread and to determine the impact of genetically modified yeast RS 190 on improvement of technological properties of wheat flour 550 C by applying them for semi-rye bread making. It has been established that L. delbruecki decreases pH (3,35) medium more intensively than P. acidilactici (4,32), however by using glucoamylolytic enzymes for scald making fermentation process may be intensified. The use of enzymes for scald production results in a better activity of P. acidilactici proteolytic enzymes in leaven. L. delbruecki fermented bread are received of a better quality than fermented P. acidilactici. The quality of P. acidilactici fermented bread may be improved by using an optimum amount of glucoamylase (0,05 ml). Using of 0,030 ml glucoamylase for the scald producion slows staling process of bread (structure of the crumb changed as follows: with 0,03 ml – 2,15, with 0,05 ml – 2,54 times). The formation of acrylamide is influenced not only by lactic acid bacteria (LAB) used for fermentation, but also, by the size of bread (in 500 g pastry goods – midle acrylamide content61,55 µ/kg, in 1000 g - 40,48 µ/kg) as well. Physical structural properties of investigated wheat flour are suitable for making bread, whereas genetically modified yeast supplement is a suitable means for improvement of quality indicators of wheat bread. By using 550 C type wheat flour with... [to full text]
56

A layer of hydrogel on PET dressings for low wound adherence and as a reservoir for new dendrimer based biocides for burn wound infection control

Asghari, Sogol 23 December 2015 (has links)
Bacterial infection in burn wounds can jeopardize healing and can even lead to a patient’s death. Recently using a topical wound dressing with antimicrobial ability has been increasing. An ideal dressing for a burn wound is required to be antimicrobial, pain free and able to control the wound moisture to facilitate healing. In this research, a UV-radiation grafting method for depositing polyacrylamide (PAM) layer was used to improve the non-adherence properties of two commercially available silver based wound dressings. The dressing adherence, evaluated via an in vitro gelatine model, dramatically decreases after the deposition of PAM. This deposition did not negatively affect the antibacterial ability and cytotoxicity of the dressings. Furthermore, a poly(amidoamine) dendrimer based biocide was incorporated into PET dressings coated with poly(acrylic acid-co-acrylamide ) hydrogel. The resulting dressing was able to release a therapeutic dose of the antimicrobial agent in a sustained manner. / February 2016
57

Carbon Dots como fotossensibilizadores em rea??es de polimeriza??o

Alves, Larissa de Almeida 12 August 2016 (has links)
Disponibiliza??o do conte?do parcial, conforme Termo de Autoriza??o no trabalho. / Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-02-07T17:34:06Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) larissa_almeida_alves_parcial.pdf: 127946 bytes, checksum: d9a934a0580a850c74fd0e5efc19ebe6 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-03-06T11:41:19Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) larissa_almeida_alves_parcial.pdf: 127946 bytes, checksum: d9a934a0580a850c74fd0e5efc19ebe6 (MD5) / Made available in DSpace on 2017-03-06T11:41:19Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) larissa_almeida_alves_parcial.pdf: 127946 bytes, checksum: d9a934a0580a850c74fd0e5efc19ebe6 (MD5) Previous issue date: 2016 / Carbon Dots (CDs) sol?veis em ?gua preparados a partir da desidrata??o ?cida da celulose foram utilizados como fotossensibilizadores na polimeriza??o da acrilamida na presen?a do co-iniciador trietanolamina. Os materiais preparados foram caracterizados por diferentes t?cnicas, incluindo MET, IVFT, espectroscopia UV-Vis e fotoluminesc?ncia, voltametria c?clica, TG-MS, titula??o potenciom?trica, entre outras. Os Carbon Dots preparados apresentaram tamanho de part?culas de aproximadamente 2,7 ?0,5nm, com uma superf?cie altamente funcionalizada com grupos funcionais oxigenados (carbox?licos, fen?licos, pironas, etc.) dos quais 65% s?o carbox?licos. Uma vez que estes grupos apresentam pKa ao redor de 4, potenciais zeta negativos foram observados em pHs ?cidos maiores que 4. Por outro lado, as caracteriza??es das suas propriedades ?pticas mostraram que os Carbon Dots apresentam uma absortividade molar (?) de 20,1 Lg-1cm-1 em ?= 254nm e 7,6 Lg-1cm-1 em ?= 360 com fotoluminesc?ncia dependente do comprimento de onda de excita??o e rendimento qu?ntico de 0,6%. Devido ?s suas propriedades, os Carbon Dots foram usados como fotossensibilizadores na polimeriza??o da acrilamida. A cin?tica da rea??o de polimeriza??o foi realizada em pHs 3, 6, 8 e 10, sendo que em pH 8 foi verificada uma maior taxa de convers?o. Neste pH as nanoestruturas possuem um pequeno excesso de carga negativa e a estrutura da trietanolamina est? predominantemente desprotonada (pKa = 7,86) o que facilita a intera??o das duas esp?cies promovendo a forma??o de radicais iniciadores da rea??o. O material fotopolimerizado foi caracterizado e os resultados obtidos s?o t?picos de poliacrilamida. Em adi??o, o material polim?rico obtido foi sol?vel em ?gua sugerindo que o pol?mero seja linear (n?o apresenta reticula??es) com uma massa molar viscosim?trica de at? 3,1x106 Da. A partir dos resultados experimentais obtidos e c?lculos te?ricos da estrutura de ambos, fotossensibilizador e co-iniciador, foi sugerido que devido ? capacidade dos Carbon Dots em receber el?trons em sua estrutura de bandas, sua alta absortividade molar e fotoestabilidade, as nanoestruturas quando excitadas foram capazes de gerar radicais amino, respons?veis pela inicia??o da polimeriza??o, devido ao acoplamento entre seus orbitais de fronteira com os orbitais HOMO-LUMO da trietanolamina. Por fim, os resultados apresentados demonstram uma nova e promissora aplica??o para estas nanopart?culas, com um grande potencial para o desenvolvimento futuro das tecnologias relacionadas ? fotopolimeriza??o. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Qu?mica, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / Water soluble Carbon Dots (CDs) prepared from the acid dehydration of cellulose were used as photosensitizers in the polymerization of the acrylamide in the presence of co-initiator triethanolamine. The prepared materials were characterized by different techniques, including TEM, FTIR, UV-Vis spectroscopy and photoluminescence, cyclic voltammetry, TG-MS, potentiometric titration, among others. The Carbon Dots prepared showed the particle size of approximately 2.7 ? 0.5nm and a highly functionalized surface with oxygenated functional groups (carboxylic, phenolic, pyrones, etc.) 65% of them carboxylic. Since these groups have pKa around 4, negative zeta potentials were observed uawes of pH hifher than 4. Furthermore, the characterization of their optical properties showed that Carbon Dots exhibit a molar absorptivity (?) de 20.1 Lg-1cm-1 in ?= 254nm e 7.6 Lg-1cm-1 in ?= 360 with photoluminescence dependent of the excitation wavelength and quantum efficiency of 0.6%. Because their properties, the carbon dots were used as photosensitizers in the polymerization of the acrylamide. The kinetics of the polymerization reaction was carried out at pH 3,6,8 and 10, whereas at pH 8 was observed a higher conversion rate. At this pH the nanostructures have a small excess of negative charge and the structure of triethanolamine are predominantly deprotonated ( pKa = 7.86) that facilitates the interaction of the two species promoting the formation of radical reaction initiators. The polymeric material was characterized and the obtained results are typical of polyacrylamide. In addition, the polymerized material was water soluble and suggests that the polymer is linear (no presents crosslinks) and has a molecular weight of approximately 3.1x106 Da. The experimental results and theoretical calculations of the band structure of both, photosensitizer and co-initiator, suggest that due to the ability of Carbon Dots to receive electrons in its band structure, their high molar absorptivity and photostability, these nanostructures when excited were able to generate amine radicals, responsible for initiating polymerization, due to the coupling between their frontier orbitals with the HOMO-LUMO of triethanolamine. Finally, the results show a promising new application for carbon nanostructures in all areas related to photopolymerization.
58

Polímero eletrólito derivado de goma de cajueiro para uso como floculante no tratamento de efluentes

Klein, Jalma Maria January 2015 (has links)
Neste trabalho, um polímero eletrólito derivado de goma de cajueiro graftizada com poliacrilamida (GC-g-PAM) foi desenvolvido para uso como floculante no tratamento de águas. Foi investigado o efeito da concentração de acrilamida e do iniciador persulfato de potássio, da energia de micro-ondas e de ultrassom sobre a eficiência da reação, produtividade e viscosidade intrínseca dos copolímeros GC-g-PAM. As matérias-primas e os copolímeros graftizados foram caracterizados por espectroscopia de infravermelho, ressonância magnética nuclear, análise termogravimétrica, calorimetria exploratória diferencial e espalhamento de luz dinâmico. A síntese realizada por ultrassom permitiu a obtenção de copolímeros graftizados com elevada eficiência de grafting e viscosidade intrínseca, em curto período de tempo. Os copolímeros obtidos com baixa concentração de iniciador (1,90×10−4 mol e 2,85×10−4 mol) apresentaram raio hidrodinâmico 1,5 vezes maior do que o raio da goma de cajueiro devido à graftização de cadeias longas de poliacrilamida nas cadeias da goma de cajueiro. A estrutura química dos copolímeros graftizados afetou positivamente o desempenho destes quando utilizados como floculante no processo de floculação. Os copolímeros GC-g-PAM apresentaram eficiência superior a 90% na remoção da turbidez de suspensão aquosa de caulim, usada como referência, bem como em água de abastecimento in natura. A grande vantagem dos floculantes GC-g-PAM reside no fato destes apresentarem cadeia macromolecular biodegradável e cadeias laterais menores do que a cadeia principal da poliacrilamida comercial, não biodegradável, utilizada como floculante. O uso do floculante derivado da goma de cajueiro para recuperação e purificação de águas, em detrimento do floculante sintético, visa a longo prazo diminuir o impacto ambiental causado pelo acúmulo de floculante sintético no lodo, já que esse não é biodegradável. / In this work a polymer electrolyte derived from cashew gum with polyacrylamide (GC-g-PAM) was developed for use as a flocculant in water treatment. The effect of concentration of acrylamide and potassium persulfate initiator, as well as microwave and ultrasound energy over the grafting efficiency, productivity, and intrinsic viscosity of copolymers GC-g-PAM were investigated. The raw materials and grafted copolymers were characterized by infrared spectroscopy, nuclear magnetic resonance spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and dynamic light scattering. The synthesis performed with ultrasound allowed the achievement of grafted copolymer with high grafting efficiency and intrinsic viscosity, in a short reaction time. The copolymers obtained at low initiator concentration (1.90×10−4 mol and 2.85×10−4 mol) presented a hydrodynamic radius 1.5 times larger than the one from cashew gum due to grafting of long chains of polyacrylamide onto cashew gum backbone. The chemical structure of grafted copolymers affected positively the performance of flocculants when they were used in flocculation processes. The turbidity removal of copolymer GC-g-PAM in kaolin suspension, used as reference, and in water treatment was higher than 90%. The great advantage of flocculants GC-g-PAM lies in the fact that they show biodegradable macromolecular chain with branches that are shorter than polyacrylamide commercial, non-biodegradable, used as a flocculant. The use of flocculant derived from cashew gum for water purification and recovery, instead of synthetic flocculant, in long term will decrease the environmental impact caused by the accumulation of synthetic flocculant in the sludge, since it is non-biodegradable.
59

Post-Fire response of botanical and microbial communities in the succulent Karoo

Lucas, Lyle January 2018 (has links)
Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv & Cons Biol) / Fire as a form of disturbance is unique in the way it impacts upon the environment, acting like a herbivore with a ubiquitous appetite. Consuming both dead and living material, converting complex organic molecules into organic and mineral products, which return to the soil. The role of disturbance has long been considered a driver of diversity within Mediterranean type ecosystems. Recently the interest in soil microbes has been piqued, as the importance thereof has been emphasised, particularly their role in nutrient cycling and the chelation of essential plant nutrients. The occurrence of fire results in several environmental and ecological impacts on soil, as well as the dynamics of the microbial populations present. This study explores the impact of fire as a disturbance on the plant and bulk soil microbial communities of the Succulent Karoo. This was achieved through two sub-studies, in which three different states were studied: unburnt, 7-year and 2-year post-fire. Today microbial profiles are also used as indicators of disturbance, thus many techniques exploring microbial community composition are available.
60

Síntese e caracterização de novos bionanocompósitos híbridos constituídos por polissacarídeo carboximetilcelulose e nanoargila com possível aplicação para remoção ou liberação controlada de defensivo agrícola paraquat / Synthesis and characterization of new hybrid bionanocomposites composed of carboxymethylcellulose polysaccharide and nanoclay with possible application for removal or controlled release of paraquat pesticide

Garcia, João Antonio Farinelli 27 April 2018 (has links)
Submitted by JOÃO ANTONIO FARINELLI GARCIA (farinelligarcia@hotmail.com) on 2018-06-11T13:28:39Z No. of bitstreams: 1 Dissertação - João Antonio Farinelli Garcia.pdf: 4749849 bytes, checksum: d11924d30ad7b0fdf1f021fe7bc5cbf9 (MD5) / Approved for entry into archive by Cristina Alexandra de Godoy null (cristina@adm.feis.unesp.br) on 2018-06-14T23:47:11Z (GMT) No. of bitstreams: 1 garcia_jaf_me_ilha.pdf: 4616181 bytes, checksum: 3df8dbb185ed2224d9fa39c2985a23d5 (MD5) / Made available in DSpace on 2018-06-14T23:47:11Z (GMT). No. of bitstreams: 1 garcia_jaf_me_ilha.pdf: 4616181 bytes, checksum: 3df8dbb185ed2224d9fa39c2985a23d5 (MD5) Previous issue date: 2018-04-27 / O objetivo do trabalho foi realizar a síntese dos bionanocompósitos constituídos de carboximetilcelulose (CMC), poliacrilamida (PAAm) e diferentes concentrações de nanoargila laponita RDS (0 % referência, 1 %, 2%, 4% e 5 %), com possibilidades de aplicação em sistemas de remoção/liberação controlada de pesticida paraquat. Foi possível confirmar a formação dos bionanocompósitos constituídos de CMC/PAAm/nanoargila utilizando as técnicas de espectroscopia de absorção no infravermelho (FTIR) e microscopia eletrônica de varredura (MEV). A disposição das plaquetas de nanoargila na matriz polimérica foi avaliada pela técnica de difração de raios-X (DRX), em que resultou na possibilidade das plaquetas estarem intercaladas, além de possivelmente estarem esfoliadas. O comportamento térmico dos hidrogéis foi avaliado pelas análises termogravimétrica (TG) e calorimetria exploratória diferencial (DSC). Os bionanocompósitos se mostraram estáveis termicamente até aproximadamente 200 °C. Foi realizada a caracterização dos bionanocompósitos, determinando o grau de intumescimento (Q) em água destilada, diferentes soluções salinas (NaCl, CaCl2 e AlCl3) e soluções com diversos pH (1, 2, 4, 5, 6, 8 e 10). Observou-se uma redução nos valores de Q em baixas concentrações de nanoargila para água destilada (Q0% = 33,7 g/g para Q2% = 23,8 g/g), seguida de um acréscimo com o aumento do teor de nanoargila (Q4% = 28,4 g/g e Q5% = 33,01 g/g) em relação aos hidrogéis com 1 e 2 % de nanoargila. Foi também constatada forte influência (redução) nos valores de Q em soluções salinas, com valores aproximados de Q = 17, 16 e 8 g/g para NaCl, CaCl2 e AlCl3, respectivamente. Em soluções com pH baixo (1 e 2), os valores de Q foram aproximadamente 13-14 g/g, seguidos de um aumento para pH mais alto (4-10), com valores aproximados de 17-18 g/g. Ainda, foram determinados os parâmetros cinéticos n e k, constatando influência significativa nos valores dos parâmetros em diferentes meios de intumescimento. Porém, não foram observadas variações significativas nos valores de n e k em relação às diferentes concentrações de laponita RDS. Foram realizados estudos de adsorção e liberação do pesticida paraquat em água destilada e soluções com pH igual a 4, 7 e 10, nos quais resultaram em uma boa possiblidade de aplicação dos bionanocompósitos em sistemas de remoção/liberação controlada. / The objective of this research was to study the bionanocomposites synthesis constituted of carboxymethylcellulose (CMC), polyacrylamide (PAAm) and different contents of nanoclay laponite RDS (0% as reference, 1%, 2%, 4% and 5%), with possibility application in systems of removal/release paraquat pesticide. The confirmation of bionanocomposites formation constituted of CMC/PAAm/nanoclay was verified by the Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (MEV) techniques. It was possible to evaluate the platelets configuration of nanoclay in the polymeric matrix by X-ray diffraction (DRX), which resulted in the possibility of platelets be intercalated, and possibly exfoliated. The thermal stability of the hydrogels was investigated by analysis thermogravimetric (TG) and differential exploratory calorimetry (DSC). The results confirmed that the bionanocomposites are thermal stability until amount 200 °C. It was also realized the characterization of bionanocomposites, obtaining the swelling degree (Q) in distilled water, different saline solutions (NaCl, CaCl2 and AlCl3) and solutions with various values of pH (1, 2, 4, 5, 6, 8 and 10). It was observed a reduction in values of Q in low concentration of nanoclay to distilled water (Q0% = 33.7 g/g to Q2% = 23.8 g/g), followed of increase with additions of nanoclay content (Q4 = 28.4 g/g and Q5% = 33.0 g/g). It was also verified strong influence (reduction) in the values of Q in solutions saline which approximated values of Q = 17, 16 and 8 g/g to NaCl, CaCl2 and AlCl3, respectivelly. In solutions with low pH (1 and 2) the swelling degree was approximated 13-14 g/g that showed an increase to high pH (4-10) with approximated values of 17-18 g/g. It was determined the n and k kinetic parameters, stating the significant influence when the parameters are analyzed in different swelling solutions. However, it was not observed variations in the values of kinetic parameters when the laponite RDS was changed. Adsorption and release studies of the paraquat pesticide in distilled water and solutions with pH of 4, 7 and 10 were realized, which resulted in a good possibility of application of the bionanocomposites in controlled removal/release systems. / 1585978

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