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Estudo da remoção e degradação do fármaco zidovudina através de processos oxidativos mediados por catálise heterogêneaPONTES, Terezinha Thília e Silva 06 July 2015 (has links)
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Previous issue date: 2015-07-06 / Os Insumos Farmacêuticos Ativos (IFAs) são considerados uma nova classe de
micropoluentes orgânicos ambientais podendo causar impactos negativos aos ecossistemas.
As indústrias farmacêuticas são umas das responsáveis por essa poluição, por isso buscam
novos métodos para tratar seus efluentes. Dentre esses fármacos tem-se a Zidovudina (AZT)
que pode ser considerado um poluente de difícil degradação nos efluentes industriais via
processos convencionais, o que motivou o desenvolvimento de um método de degradação
eletroquímico com baixos custos através de uma eletrólise. O AZT foi doado pelo Laboratório
Farmacêutico do Estado de Pernambuco (LAFEPE), e caracterizado através de análise
termogravimétrica, espectroscopia de absorção na região do infravermelho e difração de
raios-X de pó. Como técnicas analíticas, a voltametria de pulso diferencial foi a primeira a ser
explorada, utilizando eletrodos de amálgama de mercúrio e carbono vítreo com e sem
deposição de zinco na superfície, para pH de 7,2 e 9,6, solução de tampão sódio-potássio de
AZT 16 mm, a fim de identificar o melhor pico de redução. Os resultados mostram que o
AZT sofre degradação com o eletrodo de amálgama e de carbono vítreo, esse último em
menor intensidade. Em busca de uma técnica menos poluente, o eletrodo de carbono vítreo foi
o que melhor se enquadrou à proposta de descontaminação de efluentes. As condições ótimas
para essa degradação foram solução de tampão sódio-potássio de AZT 16 mm em pH 9,6,
com uma corrente (I) de 0,04 A e tempo de reação de 24 horas, em que os resultados obtidos
com a Cromatografia Líquida de Alta Eficiência (CLAE) revelaram uma degradação de 100%
do fármaco Zidovudina, e formação de produtos de degradação. / Active Pharmaceuticals (AP) are considered as a new class of environmental organic
micropollutant which are causing negative impact to the ecosystems. The pharmaceutical
industries are one of the main responsible for this pollution leading to the search of new
wastewater treatment methods. Among these pharmaceuticals, the Zidovudin (AZT) may be
considered a pollutant of hard degradation profile by the conventional known methodologies
and this problem motivated the development of a low cost electrochemical degradation
method. The AT was donated by the Pernambuco State Pharmaceutical Laboratory
(LAFEPE) and characterized by thermogravimetric analysis, infrared absorption spectroscopy
and powder X-ray diffraction. The differential pulse voltammetry was first explored applying
Hg amalgam and vitreous carbon electrodes, with and without Zn surface deposition. These
conditions were tested at a H = 7.2 and pH = 9.6, using a 16 mm AZT in a sodium-phosphate
buffer in order to identify and optimize the reduction peak. The results show that the AZT
degrades when the amalgam and the vitreous carbon are applied. Searching for a less pollutant
technique, the vitreous carbon electrode was chosen for the continuation of the studies. The
optimized experimental conditions were found to be: 16 mm AZT in a sodium-phosphate
buffer, with a current of I = 0.04 A, and 24 h reaction time. The High Performance Liquid
Chromatography revealed 100% degradation for the AZT drug and the occurrence of
degradation products. The present study shows the possibility of its use in the
decontamination of the AZT industrial production wastewater.
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Role of basement membranes and their break-down in human carcinomas:a study by <em>in situ</em> hybridization and immunohistochemistry of the expression of laminin chains, matrix metalloproteinases (MMPs) and their tissue inhibitors of metalloproteinases (TIMPs)Määttä, M. (Marko) 19 October 2000 (has links)
Abstract
In malignancies many alterations involving matrix macromolecule synthesis, secretion and assembly into basement membranes (BMs) as well as their degradation are present. The most important groups associated with matrix turnover are matrix metalloproteinases (MMPs) and their inhibitors (TIMPs).
In this study altogether 285 tissue samples were investigated comprising various malignant epithelial tumors and normal tissue structures, in which the distribution of different laminin chains was studied immunohistochemically. Laminin α5, β1 and γ1 were detected almost in all the BMs studied including normal tissues and malignancies, whereas α1 chain of laminin was present only in certain BMs. Laminin γ2 chain was solely expressed by epithelial BMs and was present in intracellular space especially in individual carcinoma cells infiltrating in the tumor stroma and in tumor cells in close contact with BM zone. Generally epithelial tumors contained quite well-formed BMs around their tumor clusters, except for infiltrative breast carcinoma and diffuse type gastric carcinoma. In situ hybridization revealed that only epithelial cells contained mRNAs for laminin α1 and γ2 chains, whereas laminin β1 chain and α1(IV) collagen were synthesized mainly by stromal cells.
mRNA for MMP-2 was produced mainly by stromal cells in hepatocellular carcinoma of liver (HCC) and pancreatic adenocarcinoma, whereas MMP-9 and MT1-MMP were equally synthesized by carcinoma cells and cells of tumor stroma. However, in HCCs of grade III carcinoma cells predominated in their MT1-MMP expression. All three MMPs were immunolocalized to malignant epithelial cells and showed variably stromal cell positivity. Statistically mRNA synthesis for MT1-MMP was significantly associated with the shortened survival of patients with HCC (P ≤ 0.01).
TIMP-1-3 mRNA, and especially TIMP-3, expressions in normal endometrium were significantly increased in endometrial stromal cells towards the secretory phase. In various endometrial hyperplasias TIMPs and MT1-MMP expressions were quite comparable to those seen in proliferating endometrium. In endometrial adenocarcinomas their expressions were significantly increased and the most intensified mRNA expressions were seen in grade III adenocarcinomas. Especially TIMP-3 and MT1-MMP mRNAs were synthesized by carcinoma cells.
The results indicate that epithelial malignancies are capable of active synthesis and assembly of BM macromolecules. Simultaneous matrix synthesis and degradation seen in malignancies suggest that the mechanisms involved in matrix turnover are not lost during malignant transformation. mRNA synthesis for MMPs and TIMPs is generally increased in epithelial malignancies. The results therefore strongly support the concept that MMPs have an active role in carcinoma cell invasion.
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Impacts of degradation on critically endangered Oudtshoorn GannaveldWheeler, Alan David January 2010 (has links)
Philosophiae Doctor - PhD / In the Succulent Karoo biome of South Africa vegetation degradation by overgrazing is a recognized threat to biodiversity. In the eastern Little Karoo region of the Western Cape Province, ostrich farming has degraded large areas of natural vegetation, particularly in the Gannaveld habitat of the Oudtshoorn basin. Little quantified vegetation data exists on the impacts of degradation and the composition of the Gannaveld vegetation types. This study quantifies the composition of Oudtshoorn Gannaveld and the impacts of degradation on this critically endangered vegetation type. The diversity of this vegetation type is added to by the occurrence of mima-like circular soil mounds, termitaria, which support distinctive plant assemblages. Perennial plant data and soil data were collected from the largest remaining remnant of Oudtshoorn Gannaveld perceived to contain different levels of degradation from near pristine to severely degraded. The results show 72 species in 49 genera and 17 families were recorded with the Aizoaceae, Asteraceae and Amaranthaceae families being dominant. The off termitaria plant community is dominated by the Asteraceae, Aizoaceae and Crassulaceae families while the on termitaria community is dominated by the Asteraceae, Amaranthaceae and Zygophyllaceae families. Four levels of degradation were identified in each of the broader on and off termitaria communities. It was found that grazing and trampling induced degradation on termitaria results in the loss of perennial plant cover and plant litter and an increase in bare ground while degradation off termitaria results in a loss of species. There are changes in soil chemistry both on and off termitaria as a result of vegetation degradation. Degradation results in palatable species being replaced by unpalatable and disturbance indicating species. Perennial plant cover off termitaria is resilient to grazing and trampling, however species richness, plant functional type composition and the abundance of individual species are not. Species richness on termitaria is resilient to grazing and trampling but cover, plant functional type composition and the abundance of individual species are not. Degradation results in shifts from succulent and woody shrub dominated communities to dwarf succulent and dwarf succulent shrub dominated communities. These changes hold implications for agriculture,biodiversity conservation and the provision of ecosystem services.
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Global environmental governance: is there a need for a global environmental organisation?Kasker, Muhammad Sameer January 2014 (has links)
Magister Legum - LLM / In order to address the challenge of global environmental degradation and natural resource depletion, a complex and multi-layered environmental governance structure has materialised over the past few decades. There is widespread agreement that the current international environmental regime is too complex and inadequate to effectively address global environmental challenges. Thus, in order to control the threat of environmental degradation, many countries, authors, commentators and academics alike have opined that one centralised body be created for the effective control and governance of environmental matters on an international level. Governance is not the same as government. It includes the actions of the state and, in addition, encompasses actors such as communities, businesses, and Non-Governmental Organisations (hereafter referred to as NGOs). Within the context of the evolution of global environmental politics and policy, the end goal of global environmental governance is to improve the state of the environment and to eventually lead to the broader goal of sustainable development. The efficacy of global environmental governance will ultimately depend on implementation at global and domestic levels. National implementation is the ultimate key, both to the efficacy of the GEG system and to meaningful environmental improvements. In the following composition, I will critically analyse the concept of a Global Environmental Organisation (hereafter referred to as a GEO) and discuss whether the formation of such an establishment is indeed necessary to handle environmental matters on an international scale.
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The Bill of Rights as the cornerstone of environmental justice in South Africa : an analysis of section 24Dheka, Lawrence January 2015 (has links)
Magister Legum - LLM
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General Fate Model for Microconstituents in an Activated Sludge SystemBanihashemi, Bahman January 2014 (has links)
Mathematical models elaborated for removal of microconstituents (MCs) in activated sludge (AS) system have not incorporated developments in International Water Association (IWA) models. In this thesis, sorption and biodegradation kinetic models that can be applied to describe transformation of MCs in an AS process were evaluated (volatilization and photodegradation were considered negligible).
Bisphenol-A (BPA), 17α-ethinylestradiol (EE2), and triclosan (TCS) have been selected as target compounds in this thesis. Sorption batch tests were conducted to retrieve kinetic and equilibrium data. Nine lab-scale continuous flow porous-pot bioreactors operating at various solids retention times (SRTs) and hydraulic retention times (HRTs) were studied for biodegradation of MCs. The effects of SRT, HRT and the biomass concentration on sorption and removal of MCs were also investigated and the results of each phase were incorporated into MCs fate models. Freundlich and linear sorption isotherms and pseudo-second-order kinetic models with different kinetic rates were found to best fit the sorption and desorption results. The result of biodegradation study in the presence of 20 µg/L of MCs demonstrated 90-98, 63-91 and 97-98% mean removal rates of BPA, EE2 and TCS, respectively, in systems operating at SRT of 5–15 d and HRT of 4-10 h. Calculation of mass fluxes of selected MCs in the dissolved and particulate phases showed that biotransformation was the principal removal mechanism of targeted MCs.
The fate models for the degradation mechanism of selected MCs were evaluated by applying various mathematical models. The pseudo-second-order model was found to best fit the results when active MCs degraders (XC) were used in the model. It was found that biodegradation studies should incorporate XC and not mixed liquor suspended solids concentration in their kinetic formulations. Therefore, the result of this study could be seen in the context, where the active MCs degraders are proposed to reduce the variability of biodegradation kinetic rates in AS systems operating at different operational conditions. Finally nitrification inhibitors, allylthiourea (ATU) were added to reactors and it was found that although nitrification process affects the fate of MCs in AS system, heterotrophs were most likely responsible for the biotransformation of the targeted MCs.
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Hydrologic responsiveness of a Lower Fraser Valley lowland soilAbbaspour, Karim January 1988 (has links)
Soil degradation in the lowland soils of the Lower Fraser Valley area is an off-season (September-April) problem. The legacy of the degradation process is encountered every year in the form of ponding which delays farming operations such as cultivation and seeding.
It is common for the lowland soils in west Delta to be left in a bare, loose, and therefore unstable state in the fall after harvest. As the result of raindrop impact on such a soil, a disaggregation process takes place which decreases the saturated hydraulic conductivity, the saturated water content, the air entry pressure head, and the water releasing ability of a soil. As a result of these changes the hydrologic responsiveness of a soil will decrease, decreasing its ability to allow rapid infiltration and drainage.
The objective of this thesis was firstly, to investigate the causes of the soil structural degradation and secondly, to use some of the soil structural parameters to optimize the responsiveness of a soil and thirdly, to suggest a management model with the objective of improving the hydrologic responsiveness of a lowland soil.
To fulfill the above objectives, in the first chapter, the process of soil degradation was studied on large undisturbed soil columns removed from two adjacent locations within an area of Ladner in west Delta, British Columbia. It was found that a disaggregation process caused by the impact of raindrops on a weakly aggregated soil was the main cause of a low hydrologic responsiveness at the beginning of the cultivation season.
As a result of degradation of the soil surface layer, a surface seal can form with a saturated hydraulic conductivity in the order of 9.7x10⁻¹⁰ m s⁻¹. A surface seal can effectively decrease the infiltration rate, leading to the formation of a persistent pond which will make a soil untrafficable and unworkable.
In the second chapter, a concept of "designer soil" was developed, where a set of "design hydrologic parameters" were identified for a partially hypothetical soil. A soil possessing hydrologic parameters better than the design parameters would therefore display a certain desired hydrologic responsiveness.
In the third chapter, a descriptive management model was suggested with the objective of achieving the design parameters as identified in the second chapter. / Land and Food Systems, Faculty of / Graduate
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Community management of wetland ecology and socio-economic costs of wetland degradation in mudaswali Wetland, Limpopo Province, South AfricaSinyati, Mollel 09 1900 (has links)
See the attached abstract below
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Synergy Between the Exoribonucleases Rrp6p and Rrp44p in the Nuclear Exosome ComplexAxhemi, Armend 29 May 2020 (has links)
No description available.
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Évolution des paysages dunaires fixés par la végétation au Niger / Veränderung der Dünenlandschaften durch die Vegetation in NigerIbrahim, Sani January 2015 (has links) (PDF)
Les sécheresses des années 1970 et 1980 ont occasionné des changements remarquables dans les paysages et écosystèmes sahéliens. Au Niger, les milieux dunaires sont les plus affectés par la dégradation des paysages aux conséquences parfois irréversibles. Cette étude tente de montrer que, malgré les modifications climatiques et les pressions anthropiques, une régénération des sols dunaires serait possible, dans cette dynamique complexe. Cela a été démontré à travers l’analyse micromorphologique des matériaux des parties superficielles des sols (0-20 cm). L’étude des caractéristiques particulières des croûtes (organisations pelliculaires de surface des sols) offre des pistes de recherches pouvant proposer des moyens et méthodes de fixation des dunes dégradées. Elle propose également des alternatives de lutte contre l’érosion éolienne et hydrique dans les écosystèmes sahéliens. Ceci cadre parfaitement avec la situation au Niger, où les phénomènes de désertification et d’ensablement des cuvettes interdunaires constituent une préoccupation majeure en matière de protection de l’environnement. / Die Dürrephasen der 1970er und 1980er Jahre haben in den Landschaften und Ökosystemen des Sahel deutliche Veränderungen verursacht. In Niger waren die Dünenlandschaften am stärksten von Degradation betroffen, teils in irreversiblem Ausmaß. Die vorliegende Studie zeigt, dass in dieser komplexen Dynamik trotz Klimaschwankungen und Nutzungsdruck die Regeneration von Böden dennoch möglich ist. Dies wurde anhand mikromorphologischer Analysen von oberflächigem Bodenmaterial (0-20 cm Tiefe) nachgewiesen. Die Untersuchung insbesondere der Eigenschaften von Oberflächenkrusten (i.S. von filmartiger Organisation der Bodenoberfläche) eröffnet Forschungsperspektiven zu Möglichkeiten und Methoden der Stabilisierung degradierter Dünen. Ebenso zeigt sie Alternativen auf im Kampf gegen äolische und durch Spülprozesse hervorgerufene Abtragung in sahelischen Ökosystemen. Damit lässt sie sich perfekt auf die Situation in Niger anwenden, wo die Phänomene der Desertifikation und der Sandeinwehung in interdunäre Wannen im Rahmen des Umweltschutzes eine wesentliche Herausforderung darstellen.
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