24 resultados para pectic substances


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Ionic Liquids (ILs) belong to a class of compounds with unusual properties: very low vapour pressure; high chemical and thermal stability and the ability to dissolve a wide range of substances. A new field in research is evaluating the possibility to use natural chiral biomolecules for the preparation of chiral ionic liquids (CILs). This important challenge in synthetic chemistry can open new avenues of research in order to avoid some problems related with the intrinsic biodegradability and toxicity associated to conventional ILs. The research work developed aimed for the synthesis of CILs, their characterization and possible applications, based on biological moieties used either as chiral cations or anions, depending on the synthetic manipulation of the derivatives. Overall, a total of 28 organic salts, including CILs were synthesized: 9 based on L-cysteine derivatives, 12 based on L-proline, 3 based on nucleosides and 4 based on nucleotides. All these new CILs were completely characterized and their chemical and physical properties were evaluated. Some CILs based on L-cysteine have been applied for discrimination processes, including resolution of racemates and as a chiral catalyst for asymmetric Aldol condensation. L-proline derived CILs were also studied as chiral catalysts for Michael reaction. In parallel, the interactions of macrocyclic oligosugars called cyclodextrins (CDs) with several ILs were studied. It was possible to improve the solubility of CDs in water and serum. Additionally, fatty acids and steroids showed an increase in water solubility when ILs-CDs systems were used. The development of efficient and selective ILs-CDs systems is indispensable to expand the range of their applications in host-guest interactions, drug delivery systems or catalytic reactions. Novel salts derived from nucleobases were used in order to enhance the fluorescence in aqueous solution. Additionally, preliminary studies regarding ethyl lactate as an alternative solvent for asymmetric organocatalysis were performed.

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Arsenic compounds are highly toxic substances; nevertheless they are used in the treatment of acute promyelocytic leukaemia. Therefore it is pressing to gain knowledge on its toxicity and detoxification mechanisms. The cellular entry pathways have been discovered and by transcriptome analysis it is known that arsenic activates the transcription of genes activated by, among others, Rpn4, Met4 and Yap1.(...)

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Ion Mobility Spectrometry coupled with Multi Capillary Columns (MCC -IMS) is a fast analytical technique working at atmospheric pressure with high sensitivity and selectivity making it suitable for the analysis of complex biological matrices. MCC-IMS analysis generates its information through a 3D spectrum with peaks, corresponding to each of the substances detected, providing quantitative and qualitative information. Sometimes peaks of different substances overlap, making the quantification of substances present in the biological matrices a difficult process. In the present work we use peaks of isoprene and acetone as a model for this problem. These two volatile organic compounds (VOCs) that when detected by MCC-IMS produce two overlapping peaks. In this work it’s proposed an algorithm to identify and quantify these two peaks. This algorithm uses image processing techniques to treat the spectra and to detect the position of the peaks, and then fits the data to a custom model in order to separate the peaks. Once the peaks are separated it calculates the contribution of each peak to the data.

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RESUMO: INTRODUÇÃO: A OMS (2001) revela que cerca de 450 milhões de pessoas sofrem de perturbações mentais ou comportamentais em todo o mundo, mas apenas uma pequena minoria tem tratamento, ainda que elementar. Transformam-se em vítimas por causa da sua doença e convertem-se em alvos de estigma e discriminação. O suicídio é considerado como um grande problema de saúde pública em todo o mundo, é uma das principais causas de morte de jovens adultos e situa-se entre as três maiores causas de morte na população entre 15-34 anos (OMS, 2001). As perturbações mentais aumentam o risco de suicídio. A depressão, esquizofrenia, e a utilização de substâncias incrementam o risco de suicídio. Estudos (Sartorius, 2002; Magliano et al., 2012) mostram que os profissionais de saúde, tal como o público em geral, podem ter atitudes negativas e estigma em relação às pessoas com perturbações mentais, podendo agir em conformidade, uma vez feito e conhecido o diagnóstico psiquiátrico. Os clínicos gerais são os receptores das perturbações mentais e tentativas de suicídio nas principais portas de entrada no acesso a cuidados de saúde. As crenças, conhecimentos e contacto com a doença mental e o suicídio, podem influenciar a atenção clínica. OBJECTIVOS: Avaliar o estigma e as percepções dos médicos de clínica geral em relação às tentativas de suicídio, o suicídio e perturbações mentais bem como os possíveis factores associados a estes fenómenos. MATERIAIS E MÉTODOS: Estudo do tipo transversal, combinando métodos quantitativos e qualitativos. A amostra é constituída por 125 sujeitos, médicos de clínica geral. Utilizaram-se as versões adaptadas dos seguintes instrumentos: Questionário sobre Percepções e Estigma em Relação à Saúde Mental e ao Suicídio (Liz Macmin e SOQ, Domino, 2005) e a Escala de Atitudes sobre a Doença Mental (Amanha Hahn, 2002). Para o tratamento estatístico dos dados usou-se a estatística 1) descritiva e 2) Análise estatística das hipóteses formuladas (Qui Quadrado - 2) a correlação entre variáveis (Spearman: ρ, rho). Os dados conectados foram limpos de inconsistências com base no pacote informático e estatístico SPSS versão 20. Para a aferição da consistência interna foi usado o teste de Alfa de Cronbach. RESULTADOS: Uma boa parte da amostra (46.4%) refere que não teve formação formal ou informal em saúde mental e (69.35%) rejeitam a ideia de que “grupos profissionais como médicos, dentistas e psicólogos são mais susceptíveis a cometer o suicídio”. Já (28.0%) têm uma perspectiva pessimista quanto a possibilidade de recuperação total dos sujeitos com perturbação mental. Sessenta e oito(54.4%) associa sujeitos com perturbação mental, a comportamentos estranhos e imprevisíveis, 115 (92.0%) a um baixo QI e 35 (26.7%) a poderem ser violentas e e perigosas. Os dados mostram uma associação estatisticamente significativa (p0.001) entre as variáveis: tempo de serviço no SNS, recear estar perto de sujeitos com doença mental e achar que os sujeitos com doença mental são mais perigosos que outros. Em termos estatísticos, existe uma associação estatitisticamente significativa entre as duas variáveis(X2=9,522; p0.05): percepção de que “é vergonhoso ter uma doença mental” e os conhecimentos em relação à doença mental. Existe uma correlação positiva, fraca e estatisticamente significativa entre os conhecimentos dos clínicos gerais(beneficiar-se de formação em saúde mental) e a percepção sobre os factores de risco (0,187; P0,039). DISCUSSÃO E CONCLUSÕES: A falta de conhecimento sobre as causas e factores de risco para os comportamentos suicidários, opções de intervenção e tratamento, particularmente no âmbito da doença mental, podem limitar a procura de ajuda individual ou dos próximos. Percepções negativas como o facto de não merecerem prioridade nos serviços, mitos (frágeis e cobarde, sempre impulsivo, chamadas de atenção, problemas espirituais) podem constituir-se como um indicador de que os clínicos gerais podem sofrer do mesmo sistema de estigma e crenças, de que sofre o público em geral, podendo agir em conformidade (atitudes de afastamento ereceio). As atitudes são influenciadas por factores como a formação, cultura e sistema de crenças. Sujeitos com boa formação na área da saúde mental têm uma percepção positiva e optimista sobre os factores de risco e uma atitude positiva em relação aos sujeitos com doença mental e comportamentos suicidários.-------------ABSTRACT: INTRODUCTION: The WHO (2001) reveals that about 450 million people suffer from mental or behavioral disorders worldwide, but only a small minority have access to treatment, though elementary. They become victims because of their disease and they become the targets of stigma and discrimination. Suicide is seen as a major public health problem worldwide, is a leading cause of death for young adults and is included among the three major causes of death in the population aged 15-34 years (WHO, 2001). Mental disorders increase the risk of suicide. Depression, schizophrenia, and the substances misuse increase the risk of suicide. Studies (Sartorius, 2002; Magliano et al, 2012) show that health professionals, such as the general public, may have negative attitudes and stigma towards people with mental disorders, and can act accordingly after psychiatric diagnosis is known. General practitioners are the main entry points of mental disorders and suicide attempts in the health sistem. Beliefs, knowledge and contact with mental illness and suicide, may influence clinical care. OBJECTIVES: To assess stigma and perceptions of general practitioners in relation to suicide attempts, suicide and mental disorders as well as possible factors associated with these phenomena. MATERIAL AND METHODS: This was a descriptive cross-sectional study, combining quantitative and qualitative methods. The sample consisted of 125 subjects, general practitioners. We used adapted versions of the following instruments: Questionnaire of Perceptions and Stigma in Relation to Mental Health and Suicide (Liz Macmin and SOQ, Domino, 2005) and the Scale of Attitudes on Mental Illness (Tomorrow Hahn, 2002). For the statistical treatment of the data we used: 1) descriptive (Data distribution by absolute and relative frequencies for each of the variables under study (including mean and standard deviation measures of central tendency and deviation), 2) statistical analysis of hypotheses using (Chi Square - 2, a hypothesis test that is intended to find a value of dispersion for two nominal variables, evaluating the association between qualitative variables) and the correlation between variables (Spearman ρ, rho), a measure of non-parametric correlation, which evaluates an arbitrary monotonic function can be the description of the relationship between two variables, without making any assumptions about the frequency distribution of the variables). For statistical analysis of the correlations were eliminated subjects who did not respond to questions. The collected data were cleaned for inconsistencies based on computer and statistical package SPSS version 20. To measure the internal consistency was used the Cronbach's alpha test. RESULTS: A significant part of the sample 64 (46.4%) reported no formal or informal training in mental health and 86 (69.35%) reject the idea that "professional groups such as doctors, dentists and psychologists are more likely to commit suicide." On the other hand, 42 (28.0%) have a pessimistic view of the possibility of full recovery of individuals with mental disorder. Sixty-eight ( 54.4 % ) of them associates subjects with mental disorder to strange and unpredictable behavior, 115 ( 92.0 % ), to low IQ, 35 ( 26.7 % ) and even to violent and dangerous behavior, 78 ( 62.4 % ) The data show a statistically significant (p = 0.001) relationship between the following variables: length of service in the NHS, fear of being close to individuals with mental illness and considering individuals with mental illness more dangerous than others. In statistical terms, there is a dependency between the two variables (X2 = 9.522, p> 0.05): the perception that "it is shameful to have a mental illness" and knowledge regarding mental illness. There is a positive and statistically significant weak correlation between knowledge of general practitioners (benefit from mental health training) and the perception of the risk factors (0,187; P0,039). DISCUSSION AND CONCLUSIONS: The lack of knowledge about the causes and risk factors for suicidal behavior, intervention and treatment, particularly in the context of mental illness options, may decreaseseeking for help by individual and their relatives. Negative perceptions such as considering that they dont deserve priority in services, myths (weak and cowards, always impulsive, seeking for attentions, spirituals problems) may indicate that general practitioners, may suffer the same stigma and beliefs systems as the general public, and can act accordingly (withdrawal and fear attitudes). Attitudes are influenced by factors such as education, culture and belief system. Subjects with good training in mental health have a positive and optimistic perception of the risk factors and a positiveattitude towards individuals with mental illness and suicidal behaviour.

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The goal of this thesis is the investigation and optimization of the synthesis of potential fragrances. This work is projected as collaboration between the University of Applied Sciences in Merseburg and the company Miltitz Aromatics GmbH in Bitterfeld‐Wolfen (Germany). Flavoured compounds can be synthesized in different ways and by various methods. In this work, methods like the phase transfer catalysis and the Cope‐rearrangement were investigated and applied, for getting a high yield and quantity of the desired substances and without any by‐products or side reactions. This involved the study of syntheses with different process parameters such as temperature, solvent, pressure and reaction time. The main focus was on Cope‐rearrangement, which is a common method in the synthesis of new potential fragrance compounds. The substances synthesized in this work have a hepta‐1,5‐diene‐structure and that is why they can easily undergo this [3,3]‐sigma tropic rearrangement. The lead compound of all research was 2,5‐dimethyl‐2‐vinyl‐4‐hexenenitrile (Neronil). Neronil is synthesized by an alkylation of 2‐methyl‐3‐butenenitrile with prenylchloride under basic conditions in a phase‐transfer system. In this work the yield of isolated Neronil is improved from about 35% to 46% by according to the execution conditions of the reaction. Additionally the amount of side product was decreased. This synthesized hexenenitrile involved not only the aforementioned 1,5‐diene‐structure, but also a cyano group, that makes this structure a suitable base for the synthesis of new potential fragrance compounds. It was observed that Neronil can be transferred into 2,5‐dimethyl‐2‐vinyl‐4‐hexenoic acid by a hydrolysis under basic conditions. After five hours the acid can be obtained with a yield of 96%. The following esterification is realized with isobutanol to produce 2,5‐dimethyl‐2‐vinyl‐4‐hexenoic acid isobutyl ester with quantitative conversion. It was observed that the Neronil and the corresponding ester can be converted into the corresponding Cope‐product, with a conversion of 30 % and 80%. Implementing the Cope‐rearrangement, the acid was heated and an unexpected decarboxylated product is formed. To achieve the best verification of reaction development and structure, scrupulous analyses were done using GC‐MS, 1H‐NMR and 13C‐ NMR.

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RESUMO - Enquadramento: À semelhança do que tem acontecido com o risco de reacções adversas a medicamentos (RAM), também o risco de reacções adversas a suplementos alimentares tem aumentado gradualmente, com o aumento do consumo destes produtos definidos como géneros alimentícios comuns. Existem vários estudos publicados na área das RAM e alguns na área dos suplementos alimentares, mas a maior parte da investigação decorre em contexto hospitalar, sendo raros os estudos realizados nos cuidados de saúde primários (CSP). Assim, o presente estudo, ao avaliar a percepção dos profissionais de saúde dos CSP face à segurança dos suplementos alimentares, pretende contribuir para o aumento do conhecimento nesta área, o que permitirá o desenvolvimento de estratégias adequadas, que reduzam a ocorrência de eventos adversos e protejam a população. Métodos: Trata-se de um estudo observacional, transversal e analítico, com recurso a inquérito por questionário desenvolvido para o efeito. O presente estudo incluiu todos os profissionais de saúde dos Agrupamentos de Centros de Saúde (ACeS) Lisboa Central e Pinhal Litoral que aceitaram participar. Globalmente, a amostra do estudo (n=190) corresponde a 28% da população de profissionais de saúde dos dois ACeS. Resultados: O presente estudo permitiu concluir que muitos dos profissionais de saúde (64 a 93%) considera que a toma de suplementos alimentares pode representar algum risco para a saúde dos consumidores. Referem inclusivamente conhecer algumas reacções adversas associadas ao consumo destas substâncias, embora a maioria (85%) admita desconhecer a forma adequada de proceder à sua notificação. Contudo, esse conhecimento dos riscos para a saúde, ou mesmo das reacções adversas associadas, não parece condicionar os hábitos de prescrição ou aconselhamento aos utentes nem os hábitos de consumo pessoal de suplementos alimentares. Conclusões: Os resultados obtidos reforçam a necessidade de realização de mais estudos nesta área. Parece igualmente necessário o envolvimento dos Conselhos Clínicos e de Saúde dos ACeS na promoção da notificação de eventos adversos e a aposta na formação dos profissionais de saúde na área dos suplementos alimentares.

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RESUMO - O aumento dos produtos processados na alimentação diária, em especial das crianças, tem repercussões no consumo aumentado de aditivos, cujas consequências são ainda ambíguas. Associado ao aumento do consumo deste tipo de alimentos encontra-se a prevalência de excesso de peso e obesidade infantil. O presente estudo exploratório pretendeu avaliar a exposição a aditivos alimentares em crianças dos 0 aos 3 anos, com base nos Limites Máximos de Utilização e nas Doses Diárias Admissíveis, e estudar a sua associação com variáveis como a idade, sexo, percentil de Índice de Massa Corporal e nível de escolaridade dos Pais. Pretendeu-se também identificar as categorias de alimentos consumidas que mais contribuíram para a exposição aos aditivos alimentares em estudo. Com base numa amostra de dados reportados em diários alimentares, foram selecionados 12 aditivos. Observaram-se ingestões estimadas superiores às DDA, para o dióxido de enxofre (E220), o ácido fumárico (E297) e o nitrito de sódio (E250). As categorias de alimentos “Açúcar, confeitaria e sobremesas açucaradas”, “Leite e produtos lácteos”, “Cereais e derivados” e “Pratos compostos”, foram as que mais contribuíram para a exposição dos aditivos selecionados. O presente trabalho permitiu inferir o perfil de exposição a aditivos alimentares em crianças, lançar resultados preliminares para justificar a necessidade de estudos mais pormenorizados, e a criação do sistema de monitorização nacional da ingestão de aditivos. Estudos sobre consumos de aditivos alimentares podem servir de base para elaboração de estratégias de saúde pública, com a finalidade de reduzir o consumo destas substâncias e promover hábitos alimentares mais saudáveis.

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In order to address and resolve the wastewater contamination problem of the Sines refinery with the main objective of optimizing the quality of this stream and reducing the costs charged to the refinery, a dynamic mass balance was developed nd implemented for ammonia and polar oil and grease (O&G) contamination in the wastewater circuit. The inadequate routing of sour gas from the sour water stripping unit and the kerosene caustic washing unit, were identified respectively as the major source of ammonia and polar substances present in the industrial wastewater effluent. For the O&G content, a predictive model was developed for the kerosene caustic washing unit, following the Projection to Latent Structures (PLS) approach. Comparison between analytical data for ammonia and polar O&G concentrations in refinery wastewater originating from the Dissolved Air Flotation (DAF) effluent and the model predictions of the dynamic mass balance calculations are in a very good agreement and highlights the dominant impact of the identified streams for the wastewater contamination levels. The ammonia contamination problem was solved by rerouting the sour gas through an existing clogged line with ammonia salts due to a non-insulated line section, while for the O&G a dynamic mass balance was implemented as an online tool, which allows for prevision of possible contamination situations and taking the required preventive actions, and can also serve as a basis for establishing relationships between the O&G contamination in the refinery wastewater with the properties of the refined crude oils and the process operating conditions. The PLS model developed could be of great asset in both optimizing the existing and designing new refinery wastewater treatment units or reuse schemes. In order to find a possible treatment solution for the spent caustic problem, an on-site pilot plant experiments for NaOH recovery from the refinery kerosene caustic washing unit effluent using an alkaline-resistant nanofiltration (NF) polymeric membrane were performed in order to evaluate its applicability for treating these highly alkaline and contaminated streams. For a constant operating pressure and temperature and adequate operating conditions, 99.9% of oil and grease rejection and 97.7% of chemical oxygen demand (COD) rejection were observed. No noticeable membrane fouling or flux decrease were registered until a volume concentration factor of 3. These results allow for NF permeate reuse instead of fresh caustic and for significant reduction of the wastewater contamination, which can result in savings of 1.5 M€ per year at the current prices for the largest Portuguese oil refinery. The capital investments needed for implementation of the required NF membrane system are less than 10% of those associated with the traditional wet air oxidation solution of the spent caustic problem. The operating costs are very similar, but can be less than half if reusing the NF concentrate in refinery pH control applications. The payback period was estimated to be 1.1 years. Overall, the pilot plant experimental results obtained and the process economic evaluation data indicate a very competitive solution through the proposed NF treatment process, which represents a highly promising alternative to conventional and existing spent caustic treatment units.

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Paper submitted to e-conservation Journal: Maria Leonor Oliveira, Leslie Carlyle, Sara Fragoso, Isabel Pombo Cardoso and João Coroado, “Investigations into paint delamination and consolidation of an oil painting on copper support”.