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GE Healthcare i Boländerna, Uppsala producerar årligen 88 000 m3 vatten för medicinsk användning. Särskilda krav på hög kvalitet ställs på vattnet, internationellt klassificerat som purified water, PW. Utöver gränsvärden för en bakteriell halt ställer GE krav på halter av endotoxin, giftiga ämnen genererade från fettämnen hos gramnegativa bakterier. Under en längre period har det rena vattnet producerats genom destillation, en process där den utgående produkten har en temperatur på 90 –95 C, varpå de höga temperaturerna håller vattnet steriliserat från mikrobiell tillväxt. I huvudslingor på upp till 300 m distribueras vattnet ut till olika byggnader på anläggningen, varpå vattnet kyls ned till 20 C, där 7 l dricksvatten går åt för att kyla 1 l PW. Från och med år 2018 kommer GE att börja producera PW genom omvänd osmos och elektriska jonbytare, vilket medför den stora skillnaden att kallt vatten på 20 C bildas. Syftet med det här projektet var att hitta ett energibesparande sätt att sterilisera distributionssystemet för kallt renat vatten, vilket uppfyller kriterier för implementering i GE:s anläggning. Projektet genomfördes i huvudsak som en litteraturstudie av vetenskapliga artiklar från en rad olika databaser. Av tillgängliga metoder som analyserats, rekommenderades ozon i GE:s distributionssystem. Detta eftersom ozon är ett starkt oxiderande ämne som lämpar sig väl i PW-system samt inte kräver något stopp i GE:s produktion. Ozon kan bildas direkt från syret i luften alternativt från vattnet själv. De starka oxiderande egenskaperna gör att endast en liten mängd ozon behövs för steriliseringen, vilket genererar låga driftkostnader. Halveringstiden på ungefär 20 minuter i PW gör att det mesta ozonet bryts ned naturligt under distributionen, varpå den resterande delen kan omvandlas tillbaka till syrgas genom strålning med UV-ljus. Ozon är en säker metod som enkelt kan implementeras i GE:s nuvarande distributionssystem, med endast ett fåtal ombyggnationer och skulle vid planerad utbyggnad i framtiden spara in ytterligare kostnader genom enklare rörkonstruktioner. Om GE väljer att använda ozon som steriliseringsmetod uppskattas investeringskostnaden vara intjänad på mindre än ett år.

A água é, sem dúvida, a matéria-prima de maior volume empregada, considerando de forma global, na produção farmacêutica. Pode ser usada direta ou indiretamente, com profundo potencial de impacto na qualidade do produto e na segurança do paciente. Consiste em meio de crescimento que, embora não rico, apresenta variações em suas características microbianas. Sendo assim, os métodos tradicionais utilizados em sua análise, apesar de simples, exigem vários dias para obtenção de resultados e muitas vezes não são sensíveis o suficiente para recuperar microrganismos em determinados estados fisiológicos, como por exemplo, biofilmes ou em estado viável não cultivável. Em virtude disso, o presente trabalho foi elaborado com intuito de desenvolver pesquisas para inovar no controle de qualidade microbiológico da água utilizada para fins farmacêuticos e, além de agregar novas técnicas, visa que os produtos farmacêuticos estejam disponíveis no mercado de modo rápido, seguro, eficaz e com a qualidade desejada. Desta forma, o objetivo do presente trabalho foi avaliar o potencial das tecnologias alternativas, em específico a citometria de fluxo, no monitoramento microbiano da água purificada, de forma a assegurar a manutenção de baixo risco de falha microbiana. O estudo foi conduzido em três etapas: a primeira etapa foi denominada de prova de conceito e teve por objetivo avaliar se existia alguma correlação entre os resultados obtidos com o método alternativo com aqueles obtidos com o método tradicional; a segunda etapa foi a validação da metodologia alternativa, etapa na qual foram avaliados todos os parâmetros de validação exigidos pelas principais normas e compêndios farmacêuticos; a terceira e última etapa foi denominada de equivalência, etapa na qual foi demonstrada a equivalência entre o método alternativo e os métodos farmacopeicos quando desafiados com amostras de água purificada coletadas de reservatórios da Faculdade de Ciências Farmacêuticas (FCF/USP). Os resultados obtidos no presente estudo demonstraram que a citometria de fluxo é não só uma opção válida em relação ao método tradicional por semeadura em profundidade como também oferece como principal vantagem a possibilidade de se ter resultados em tempo real, possibilitando efetuar qualquer correção no processo produtivo a tempo. / Water certainly is the most used raw material used in pharmaceutical industry, considering volume of material and manufacturing process. It may be used either directly or indirectly, causing a considerable impact on product quality and patient safety. It may be considered a poor culture media that presents variable microbiologic characteristics. Even though the traditional microbiological methods used for water evaluation are simple, data obtainment requires several days. In addition, these methods are unable to recover microorganisms from determined physiological conditions, such as those observed in biofilms or in a viable but non-culturable state. Therefore, the present work aimed to research innovative methods for microbiologic quality control of water for pharmaceutical use. The new techniques intend to provide pharmaceutical product to market more rapidly, while maintaining its safety and quality. Specifically, the objective of this work was to evaluate alternative technologies, namely flow cytometry, and their application on microbiological assessment of purified water ensuring the low risk of microbiological fail. This study was conducted in three steps: the first, named as proof of concept, aimed to determine whether occurred any correlation between results obtained from traditional methods and results obtained from alternative method. Validation of alternative method was performed in the second step. This step was executed considering all validation parameters required for main pharmaceuticals norms and compendia. The last step was named equivalency, in which was showed the equivalence between traditional and alternative methods when challenged against purified water sampled from School of Pharmaceutical Sciences (FCF/USP) reservoirs. Results showed that flow citometry is equivalent to traditional methods and was also able to provide real-time evaluation, which enables to adjust the manufacturing process as soon as a deviation is detected.

In the book of Lau Tzu, there is a chapter saying that ¡§The highest goodness is like water¡¨. It¡¦s known that the earth is the only blue planet because of water. Water breeds infinite life and vitality and now it is experiencing a fatal moment due to human abuse in last fifty years while the human history moves into a new era. In the current days, the most important natural living elements including water need be further purified before daily usage. Water itself is now becoming an evaporating and scarce resource in the earth which affects the life of hundred million people. China economy has been growing dramatically in past decades accompanied with remarkably improvement of the living standard of people¡¦s life and income level. The beauty treatment and spa business has been developing its market in almost every province in China. Water is playing a crucial role in the treatment effectiveness and an elementary ingredient to ensure the final result of beauty treatment. The research purposes are to fist analyze the market status of the beauty treatment and functional water; secondly, is to investigate the feasibility and sales synergy in combining these two product and service lines (beauty treatment and functional water); Thirdly, is to conduct an in-depth case study for company T¡¦s marketing strategy in entering this new mixed product market. The whole research structure is divided into three sections. Section one is to collate the available academic research report and theory including market segmentation, goal setting, 4P in marketing, SWOT and competitive analysis in forming a framework of marketing strategy applied in the China beauty and functional water market. Last section is trying to leverage, verify and refine the theory framework against a series of in-depth interview and secondary data in the market. It¡¦s still in an infant stage of China beauty treatment business with an estimated size of three hundred billion RMB dollars market in year 2010. The demand of purified and functional water is soaring up with limited supply due to increasing contamination of water resources. It¡¦s foreseen a gold mine business of functional water as a means in pursuit of healthy, youth-looking and eco-compliance life. This research result also unveils the differentiation created in the beauty treatment market by introducing the functional water. It not only brings in a new profitable product lines, advances the revenues but also improve the bottom line by increasing the economical scale. The finding, last but not least, is the integration of functional water product and beauty treatment is meeting the macro trend of consumers¡¦ perception of living in a healthy, youth looking and sustaining life. On the other hand, the beauty treatment agencies will be able to increase their competitiveness, grow the business, concrete the sales channel and win the customer loyalty in a traditional fierce competition market. The objective of this research is to provide a marketing strategy in merging two product and service markets in achieving a long term business goal. Ultimately, purified and functional water are not only for the beauty treatment sales business but also targeting the consumers¡¦ daily life in preventing illness by accessing the purified water and treasuring the invaluable water resources in sustaining the earth and lives.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-05-19T12:14:27Z No. of bitstreams: 1 Amanda Emmanuelle Sales.pdf: 4982712 bytes, checksum: 90011cbdafe7a0363213b2fff5735b44 (MD5) / Made available in DSpace on 2016-05-19T12:14:27Z (GMT). No. of bitstreams: 1 Amanda Emmanuelle Sales.pdf: 4982712 bytes, checksum: 90011cbdafe7a0363213b2fff5735b44 (MD5) Previous issue date: 2015-12-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Fibrinolytic proteases are enzymes that degrade fibrin, the main component of blood clots. The accumulation of this protein leads to thrombosis responsible for cardiovascular disease including myocardial infarction. A promising alternative to thrombolytic therapy has been the production of these enzymes by microorganisms which promotes low cost, high efficiency and capacity for large scale production. This study aimed to select species of filamentous fungi isolated from Caatinga soil samples - Pernambuco - Brazil and assess their potential for production of proteases with fibrinolytic activity. Among the 36 isolates studied, 58% showed fibrinolytic activity above 100 U/mL. The microorganism with the higher activity in terms of enzyme production was Mucor subtilissimus UCP 1262 with 415 U/mL. Further optimization of the fermentation process resulted in the production of 1075 U/mL of enzymatic activity. The fibrinolytic enzyme had a capacity of enzymatic degradation of the blood clot of 16.7 % in vitro. Extraction of fibrinolytic protease produced at submerged fermentation was carried out using a PEG/ammonium sulphate aqueous two-phase system (ATPS). PEG 8000 15% and 25% ammonium sulphate were selected as the most appropriate components for extraction with Fibrinolytic Activity in salt phase: 345 U/mL; K: 0.65; Y: 253.1 % and FP: 8.8. The fibrinolytic enzyme from Mucor subitilissimus UCP 1262 was pre-purified using extractive fermentation in PEG and ammonium sulphate ATPS, in which the fungal strain was able to grown even in high salt concentration, produced and extracted simultaneously to the PEG phase. A novel protease with fibrinolytic activity was purified also by chromatographic methods using a two-step purification protocol. Compared to the crude enzyme extract, the specific activity of the enzyme increased 5.30 fold with a recovery of 36.31%. The initial crude extract with the enzyme was pre-purified using acetone precipitation and adsorbed by ion exchange chromatography on DEAE-sephadex G50. The two-dimensional electrophoresis system (2DE) coupled with SDS-PAGE showed a single protein band of approximately 15.3 kDa and isoelectric focusing point of 3.9, exhibiting a nature as an acidic enzyme. Additionally, the activity was slightly inhibited by EDTA, but significantly inhibited by PMSF and also had a higher affinity for the N-Succinyl-Ala-Ala-Pro-Phe p-nitroanilide (SAApNA) and azocasein substrates, suggesting to be a chymotrypsin-like protease. Protein unfolding induced by pH and temperature were applied to study the protein conformational changes and showed from the thermal denaturation curve, change in ellipticity at 222 nm, indicated Tm (Melting temperature) of the protein to be 58.14°C. The far UV circular dichroism (CD) of the fibrinolytic protease showed the secondary structure with most content percentage of α-helix. These results demonstrate an economical, viable enzyme purification protocol. And studying the purified fibrinolytic enzyme have established basis for elucidating mechanisms responsible for the changes in conformation of the new fibrinolytic enzyme under varying conditions of temperature and pH. This novel fibrinolytic enzyme may represent a new source of therapeutic agents to treat thrombosis diseases. / Proteases fibrinolíticas são enzimas que degradam a fibrina, o principal componente dos coágulos sanguíneos. O acúmulo da fibrina nos vasos sanguíneos leva a trombose, fenômeno responsável por doenças cardiovasculares. Uma alternativa promissora para a terapia trombolítica tem sido a produção dessas enzimas por micro-organismos que promovem baixo custo, alta eficiência e capacidade de produção em larga escala. Produzir proteases fibrinolíticas por linhagens de fungos filamentosos por fermentação submersa e desenvolver o processo de purificação utilizando Sistemas de Duas Fases Aquosas (SDFA) e cromatografia líquida, além de caracterizar bioquímico e estruturalmente a enzima. Dentre as 36 espécies estudadas, 58% apresentaram atividade fibrinolítica acima de 100 U/mL A espécie com maior atividade foi Mucor subtilissimus UCP 1262 com 415 U/mL. Foram realizados processos fermentativos que resultaram na produção de 1075 U/mL de atividade fibrinolítica, com capacidade de degradação do coágulo sanguíneo de 16,7% in vitro. A extração da protease fibrinolítica produzida por fermentação submersa foi realizada utilizando o sistema de duas fases aquosas (SDFA) com Polietileno glicol (PEG) e sulfato de amônio. O PEG 8000 (g/mol) a 15% e sulfato de amônio a 25% foi selecionado como a condição mais eficiente para a extração da enzima na fase do sal, apresentando 345 U/mL de atividade, coeficiente de partição K=0,65; Recuperação Y=253,1% e Fator de purificação FP=8,8. A protease fibrinolítica produzida por Mucor subitilissimus UCP 1262 foi também pré-purificada utilizando fermentação extrativa com SDFA (PEG e sulfato de amônio), onde a espécie fúngica foi capaz de crescer mesmo em altas concentrações de sal, produzir e extrair simultaneamente para a fase do PEG do sistema. A protease fibrinolítica foi purificada também através de métodos cromatográficos utilizando um protocolo de purificação com dois passos. O extrato bruto inicial com a enzima foi pré-clarificado utilizando precipitação com acetona e adsorção em cromatografia de troca-iônica em DEAE-sephadex G50, o qual foi capaz de aumentar a pureza em 5,30 vezes com a recuperação de 36, 31%. O sistema de eletroforese bidimensional 2DE acoplado ao SDS-PAGE mostrou uma banda única de aproximadamente 15,3 kDa e a focalização isoelétrica apresentou o ponto isoelétrico no pH 3,9, exibindo uma natureza de enzima ácida. Adicionalmente a enzima foi significativamente inibida por PMSF e alta afinidade catalítica para o substrato sintético amidolítico N-Succinyl-Ala-Ala-Pro-Phe p-nitroanilide (SAApNA) e azocaseína. Sugerindo ser uma serino-protease semelhante à quimotripsina. Desdobramento proteico induzido por pH e temperatura foram aplicados para estudar as mudanças conformacionais da enzima e mostraram através da curva de desnaturação térmica, mudança da elipticidade a 222 nm, indicando um Tm (Temperatura de desnaturação) da proteína de 58,14°C. O dicroísmo circular no UV distante (far UV CD) da protease fibrinolítica mostrou a estrutura secundária da proteína com maior teor de α-hélix. Estes resultados demonstram um protocolo de purificação de enzimas eficiente. E o estudo da enzima purificada estabeleceu bases para elucidar mecanismos responsáveis pelas mudanças de conformação de uma nova enzima fibrinolítica sob a variação de condições variadas de temperatura e pH. Esta enzima fibrinolítica pode representar uma nova fonte de agente terapêutico no tratamento de doenças trombolíticas.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-05-19T12:41:06Z No. of bitstreams: 1 Tatiana Pereira Shiu Lin Liu.pdf: 880008 bytes, checksum: 5eed3ce34aa09053744a3f45eca49b25 (MD5) / Made available in DSpace on 2016-05-19T12:41:06Z (GMT). No. of bitstreams: 1 Tatiana Pereira Shiu Lin Liu.pdf: 880008 bytes, checksum: 5eed3ce34aa09053744a3f45eca49b25 (MD5) Previous issue date: 2016-02-25 / Tannin acylhydrolase (TAH) known as tannase (E.C:3.1.1.20) is an enzyme which hydrolizes esters and lateral bonds of hydrolizable tannins. The tannic acid is a typical hydrolizable tannin, which can be hydrolized by tannase along with glucose and gallic acid. Tannase can be obtained from vegetables, animal and microbial sources. From those, the last is the most important source to obtain the enzyme. Green tea has several substances, among which catechins are a major source of antioxidant, which help in maintaining the organism.The activity and purification of tannase produced by Aspergillus melleus URM 5827 was evaluated by semi solid fermentation using seeds of mangosteen (Garcinia humilis (Vahl) C. D. Adam) as substract. Forty two cultures fungical cultures of Aspergillus were used for qualitative selection purposes in order to verify potential for tannase production. After selecting cultures, it was performed a semi solid fermentation using seeds of mangosteen as substrate. A factorial planning (2³) was used to verify the influence of production variables such as: quantity of substrate; initial moisture and amount of tannic acid over tannase activity. The purification was evaluated by ionic change chromatography at DEAE-Sephadex. Maximum activity was produced by Aspergillus melleus URM 5827 with 452.55 units per gram of dry-based substract (U/gss) using 5.0 grams of substrate, with initial moisture of 60% and 2% of tannic acid through 48 hours fermentation. The purified enzyme has a molecular weight of 69.52 kDa on Superdex G-75, while on SDS-PAGE electrophoresis showed 66.5 kDa. As for the characterization, the optimum pH and temperature was 5.5 and 40ºC, respectively, achieving thermostability at 30ºC. Coughing increases the antioxidant activity of green tea significantly. The results obtained in this study show the promising potential of tannase produced by Aspergillus melleus URM 5827 and its use in improving the antioxidant potential of green tea. / Tanino acil hidrolase (TAH) conhecida como tanase (E.C:3.1.1.20) é uma enzima que hidrolisa ésteres e ligações laterais de taninos hidrolisáveis. O ácido tânico é um típico tanino hidrolisável, que pode ser hidrolisado por tanase em glicose e ácido gálico. A tanase pode ser obtida a partir de fontes vegetais, animais e microbianas, sendo o meio microbiológico a fonte mais importante de obtenção desta enzima. O chá verde apresenta várias substâncias, dentre elas, as catequinas que são uma importante fonte de antioxidante, que ajudam na manutenção do organismo.A atividade e a purificação de tanase produzida por Aspergillus melleus URM 5827 foi avaliada por fermentação em estado sólido utilizando como substrato sementes de achachairú (Garcinia humilis (Vahl) C. D. Adam). Foram utilizadas 42 culturas de fungos do gênero Aspergillus para seleção qualitativa das culturas com potencial para produção da tanase. Com a cultura selecionada foi realizada uma fermentação em estado sólido utilizando sementes de achachairú como substrato. Um planejamento fatorial (23) foi utilizado para analisar a influência das variáveis de produção: quantidade de substrato, umidade inicial e quantidade de ácido tânico sobre a atividade da tanase. A purificação foi avaliada por cromatografia de troca iônica em DEAE- Sephadex. A máxima atividade foi produzida por Aspergillus melleus URM 5827 com 452,55 unidades por grama de substrato na base seca (U/gss) utilizando 5,0 g de substrato, com umidade inicial de 60% e 2,0% de ácido tânico em 48 horas de fermentação. A enzima purificada apresentou peso molecular de 69,52 kDa em Superdex G-75, enquanto que em eletroforese SDS-PAGE apresentou 66,5 kDa. Quanto a caracterização, apresentou pH e temperatura ótima de 5,5 e 40ºC respectivamente, obtendo termoestabilidade a 30ºC. A atividade enzimática na presença de íons, surfactantes e inibidores de protease, foi inibida na presença dos íons ZnCl2, ZnSO4 e dos surfactantes triton X-100, SDS, reduzida com os íons CaCl2, KCl, NaCl, MgSO4, CuSO4, dos surfactantes Tween 20, Tween 80 e dos inibidores de protease EDTA e β-mercaptoetanol. A tanase aumentou a atividade antioxidante do chá verde significativamente. Os resultados obtidos no presente estudo, mostram o potencial promissor da tanase produzida por Aspergillus melleus URM 5827 e na sua utilização no aumento do potencial antioxidante do chá verde.

A água é, sem dúvida, a matéria-prima de maior volume empregada, considerando de forma global, na produção farmacêutica. Pode ser usada direta ou indiretamente, com profundo potencial de impacto na qualidade do produto e na segurança do paciente. Consiste em meio de crescimento que, embora não rico, apresenta variações em suas características microbianas. Sendo assim, os métodos tradicionais utilizados em sua análise, apesar de simples, exigem vários dias para obtenção de resultados e muitas vezes não são sensíveis o suficiente para recuperar microrganismos em determinados estados fisiológicos, como por exemplo, biofilmes ou em estado viável não cultivável. Em virtude disso, o presente trabalho foi elaborado com intuito de desenvolver pesquisas para inovar no controle de qualidade microbiológico da água utilizada para fins farmacêuticos e, além de agregar novas técnicas, visa que os produtos farmacêuticos estejam disponíveis no mercado de modo rápido, seguro, eficaz e com a qualidade desejada. Desta forma, o objetivo do presente trabalho foi avaliar o potencial das tecnologias alternativas, em específico a citometria de fluxo, no monitoramento microbiano da água purificada, de forma a assegurar a manutenção de baixo risco de falha microbiana. O estudo foi conduzido em três etapas: a primeira etapa foi denominada de prova de conceito e teve por objetivo avaliar se existia alguma correlação entre os resultados obtidos com o método alternativo com aqueles obtidos com o método tradicional; a segunda etapa foi a validação da metodologia alternativa, etapa na qual foram avaliados todos os parâmetros de validação exigidos pelas principais normas e compêndios farmacêuticos; a terceira e última etapa foi denominada de equivalência, etapa na qual foi demonstrada a equivalência entre o método alternativo e os métodos farmacopeicos quando desafiados com amostras de água purificada coletadas de reservatórios da Faculdade de Ciências Farmacêuticas (FCF/USP). Os resultados obtidos no presente estudo demonstraram que a citometria de fluxo é não só uma opção válida em relação ao método tradicional por semeadura em profundidade como também oferece como principal vantagem a possibilidade de se ter resultados em tempo real, possibilitando efetuar qualquer correção no processo produtivo a tempo. / Water certainly is the most used raw material used in pharmaceutical industry, considering volume of material and manufacturing process. It may be used either directly or indirectly, causing a considerable impact on product quality and patient safety. It may be considered a poor culture media that presents variable microbiologic characteristics. Even though the traditional microbiological methods used for water evaluation are simple, data obtainment requires several days. In addition, these methods are unable to recover microorganisms from determined physiological conditions, such as those observed in biofilms or in a viable but non-culturable state. Therefore, the present work aimed to research innovative methods for microbiologic quality control of water for pharmaceutical use. The new techniques intend to provide pharmaceutical product to market more rapidly, while maintaining its safety and quality. Specifically, the objective of this work was to evaluate alternative technologies, namely flow cytometry, and their application on microbiological assessment of purified water ensuring the low risk of microbiological fail. This study was conducted in three steps: the first, named as proof of concept, aimed to determine whether occurred any correlation between results obtained from traditional methods and results obtained from alternative method. Validation of alternative method was performed in the second step. This step was executed considering all validation parameters required for main pharmaceuticals norms and compendia. The last step was named equivalency, in which was showed the equivalence between traditional and alternative methods when challenged against purified water sampled from School of Pharmaceutical Sciences (FCF/USP) reservoirs. Results showed that flow citometry is equivalent to traditional methods and was also able to provide real-time evaluation, which enables to adjust the manufacturing process as soon as a deviation is detected.

The Refcoal process is being developed to produce graphite from coal. Coal is dissolved in dimethylformamide (DMF) and sodium hydroxide (NaOH) is used as additive. After separation, the extracted coal (Refcoal) is precipitated with water and dried. The extraction process and subsequent solid-liquid separation processes have to be as efficient and cost-effective as possible. The purpose of the study was therefore to complete research on various unresolved aspects of the processes as identified by the candidate and supervisor. Extraction at 95 °C (DMF:coal:NaOH = 100:10:1), has an induction period of approximately 60 minutes observed, after which the reaction rate increases considerably. The reaction reaches completion after 360 minutes. An increase in stirring rate decreases extraction time due to the elimination of external mass-transfer limitations. The progress curves obtained for extraction at 135 °C with lower solvent-to-coal ratios differ dramatically from those obtained in previous studies, which indicates that changes in the raw materials and the experimental set-up have a great influence on the extraction at higher temperatures and concentrations. These extractions at higher temperatures using DMF:coal:NaOH ratios between 100:30:3 and 100:30:2 take approximately 360 minutes to complete and do not have an induction period as is the case with the extractions at 95 °C. It was found that the optimum DMF:coal ratio for an operating temperature of 135 °C, is 10:3. The high-temperature extractions reach completion in different time periods, depending on the amount of NaOH added to the reaction mixture. When very low concentrations of NaOH are added, the extraction will take much longer to complete and vice versa. The amount of NaOH used influences various aspects of the process. The cost analysis of the process falls beyond the scope of this investigation, but it is recommended that a thorough financial study is done to determine the optimum balance between raw materials, heat load and plant availability. The relationships between the concentration of Refcoal in the Refcoal solution and the absorbance values measured are polynomial expressions ending in downward concaves. The kinetics for the low-concentration (DMF:coal:NaOH = 100:10:1) extraction are best described by an autocatalytic reaction rate equation which is a function of coal, coal complex and NaOH concentration. A good fit was also obtained for the high temperature extractions. The rate expression is a function of both the coal and NaOH concentrations, but not of the coal complex. The sedimentation test showed promising results. The use of a thickener instead of a centrifuge to separate the insoluble material from the Refcoal solution would be a feasible cost-saving method. Filtration of the Refcoal solution (after centrifugation) using suitable filter media decreases the amount of impurities in the Refcoal. Filtration constants were determined for the best filter medium. The use of a hydrocyclone to separate the insoluble material from the extract is not recommended as it did not give the required efficiency to make the process viable. It is recommended that more tests be done under different conditions. Useful expressions were obtained for the change in viscosity with temperature for three different concentrations of Refcoal solution. It was determined that the viscosity of the Refcoal solution increases with time and it is therefore recommended that this be taken into account when equipment is being designed and plant scheduling is being done. / Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2007. / Chemical Engineering / MEng / unrestricted

A new process is being developed to produce graphite from prime coking coal. Coal is dissolved in dimethylformamide (DMF), on addition of sodium hydroxide. The minerals and undissolved coal are separated by centrifugation and filtration to give a solution (referred to as Refcoal solution or RCS). Over 90 wt % of the organic part of a flotation product, from the Tshikondeni mine, can be dissolved at temperatures ranging from room temperature to 135°C. The purified coal (referred to as Refcoal) and DMF need to be separated. the Refcoal to be coked and the DMF to be purified and recycled. This process should be as efficient as possible, whilst both products should be low in water content to minimise drying costs. The addition of water to the Refcoal solution causes precipitation to take place, forming a gel (referred to as Refcoal gel) liquid system. This mixture can be either centrifuged or filtered to give a denser gel, containing water, DMF and coal solids, and supernatant or filtrate, containing water and DMF. Different techniques and processes can be used to improve the separation of the DMF from the Refcoal by achieving a denser Refcoal gel: • Longer centrifugation times improve the density and therefore the separation, but this technique has its limits. • The use of low-temperature water improves the separation. • The use of syneresis could improve separation at a lower cost: heated standing tanks are used to expel the supernatant and therefore increase the density of the gel, thereby decreasing the required number of washing stages. • The addition of toluene at the beginning of a wash improved the removal of DMF by 20%, using centrifugation as separation method. • Pressure filtration gave a 20% improvement on centrifugation, with no additives. • The addition of toluene to the pressure filtration process gave another improvement of 15%, and after three stages the percentage of solids in the gel was 28%, the highest so far achieved. This method also resulted in the highest removal of DMF in the first stage (73% of the original DMF in the RCS was removed). Counter-current washing shows the greatest potential, using the least amount of water. The concentration of DMF in the wash solution, to gel the Refcoal solution, is a limitation of this process. If the concentration is too high, no gelling and therefore no separation can take place in the first stage. It is recommended that counter-current washing using pressure filtration should be investigated; however, this will be difficult on a laboratory scale due to the mass losses during transfers. / Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2009. / Chemical Engineering / unrestricted

Research on biosynthesis of tobacco mosaic virus (TMV) ribonucleic acid (RNA) in vitro has been reported by Cochran, et al; Karasek and Schramm; Kim and Wildman; Cornuet and Astier; and Tongur and Baland in. It has been postulated that the replication of a number of viruses containing single-stranded RNA is accompanied by the formation of a virus-specific double-stranded helical RNA, the replicative form. This has been demonstrated both for animal and bacterial viruses including MS2. The double helical structure of purified replicative form of MS2 was established by X-ray diffraction studies. One of the strands was shown to be a viral RNA strand of the parental type ("plus" strand), the other being complementary to it ("minus" strand). Studies on Escherichia coli infected with RNA phages suggest that a structure containing both a "plus 11 and a "minus " strand is an obligatory intermediate in viral reproduction.