Management consulting labs: Project TAP

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Management consulting labs: Project TAP

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Validation of alternative additives for paste production

Dissertation presented to confer Master Degree in Chemical and Biochemical Engineering

Acidogenic digestion of effluents of the cheese industry in packed bed biofilm reactors

Dissertation for the Master degree in Biotechnology

Erros pré-analíticos em anatomia patológica : prevalência, caracterização e consequências para a segurança do doente

RESUMO - A literatura disponível revela que a maioria dos erros relacionados com os exames anatomopatológicos ocorre na fase pré-analítica. Existem alguns estudos que quantificam e caracterizam estes erros mas, não foram encontrados artigos publicados sobre o tema em hospitais portugueses. Foi objetivo deste estudo determinar qual a prevalência e características dos erros pré-analíticos em amostras anatomopatológicas e as suas consequências para a segurança do doente. Analisaram-se 10574 casos de exames anatomopatológicos, de cinco hospitais da região de Lisboa e Vale do Tejo. Os serviços de anatomia patológica registaram e caracterizaram, durante vinte dias, erros detetados nas amostras anatomopatológicas com origem nos serviços requisitantes. Posteriormente os hospitais foram caracterizados quanto aos procedimentos relativos à fase pré-analítica. A prevalência de erros aferida foi de 3,1% (n=330), com um intervalo de confiança a 95% compreendido entre os valores 2,8% e 3,5%. Para além destes resultados destacam-se os seguintes pontos: i. As amostras histológicas têm 4,1% de prevalentes e as de citologia 0,9%; ii. Foram registados erros em 2,6% das requisições e em 1,5% dos contentores com as amostras; iii. A aceitação dos casos com erro é a ação mais frequente (66,9%), seguida pela devolução (24,4%) e retenção (8,7%); iv. Os hospitais com sistemas de notificação de erros e normas escritas para aceitação de amostras têm menor prevalência de erros; v. O impacte dos erros detetados na segurança dos doentes é difícil de determinar, sendo que os mais críticos relacionam-se com amostras devolvidas a fresco, meio de colheita inadequado ou com amostras danificadas. Este estudo permitiu determinar a prevalência e caracterizar os erros pré-analíticos envolvendo amostras anatomopatológicas em hospitais portugueses. Reflete a dimensão atual do problema e efetua recomendações para a sua mitigação. A prevalência de erros encontrada é inferior às publicadas em estudos semelhantes.

Avaliação clínica na disfunção fronto-estriatal : movimento e cognição

RESUMO: Os circuitos fronto-estriatais constituem um sistema em ansa fechada que une diversas regiões do lobo frontal aos gânglios da base, participando, com outras áreas cerebrais, no controlo do movimento, cognição e comportamento. As Distonias Primárias, a Doença de Parkinson e a Hidrocefalia de Pressão Normal, são doenças do movimento caracterizadas por disfunção do circuito fronto-estriatal motor. A conectividade funcional entre as diversas ansas do sistema fronto-estriatal, permite prever que as doenças do movimento possam também acompanhar-se de sintomas da esfera cognitiva e comportamental, cuja avaliação seria importante no manejo diagnóstico e terapêutico dos doentes. Objectivos Os nossos objectivos foram avaliar, por estudos clínicos, a relação entre sintomas motores, cognitivos e comportamentais em três doenças do movimento com fisiopatologias diversas - distonias Primárias, Doença de Parkinson e Hidrocefalia de Pressão Normal - analisando os dados sob a perspectiva teórica fornecida pelo conhecimentos dos vários circuitos frontoestriatais. Os nossos objectivos específicos para cada doença foram: a) Distonias Primárias: avaliação de disfunção executiva em doentes com Distonia Primária e relação com a gravidade dos sintomas motores b) Doença de Parkinson: 1. avaliação breve das funções mentais nas fases iniciais da doença, incluindo análise longitudinal para determinação de factores preditivos para declínio cognitivo; 2. relação entre a função motora e cognitiva e a Perturbação do Comportamento do sono REM, incluindo análise longitudinal; 3.avaliação de sintomas psiquiátricos, de um ponto de vista global e especificamente com incidência sobre as Perturbações do Controlo do Impulso (PCI). c) Hidrocefalia de Pressão Normal: 1. caracterização das alterações da marcha, incluindo comparação com a Doença de Parkinson; 2. caracterização das alterações cognitivas e da relação entre estas e a disfunção da marcha; 3. estudo evolutivo das alterações da marcha e cognitiva em doentes submetido a cirurgia e doentes não submetidos a cirurgia. Métodos: A Distonia Primária, a Doença de Parkinson e a Hidrocefalia de Pressão Normal foram diagnosticadas segundo critérios clínicos validados. Sempre que justificado, foram recrutados grupos de controlo, com indivíduos sem doença, emparelhados para idade, sexo e grau de escolaridade. Os doentes foram avaliados com instrumentos de aplicação clinica directa, incluindo escalas de função motora, testes neuropsicológicos globais e dirigidos às funções executivas e escalas de avaliação psiquiátrica. Testes aplicados nas Distonias Primárias: Unified Dystonia Rating Scale, Wisconsin Card Sorting Test, teste de Stroop, teste de cubos da WAIS, Teste de Retenção Visual de Benton; na Doença de Parkinson: Unified Parkinson's Disease Rating Scale, Frontal Assessment Battery (FAB), Mini-Mental State Examination (MMSE), REM-sleep behaviour disorder Questionnaire; Symptom Chek-list 90-R, Brief Psychiatric Rating Scale, FAS (fluência verbal lexical) Nomeação de Animais (Fluência verbal semântica), prova de repetição de dígitos (WAIS), Rey auditory verbal learning test, teste de Stroop, matrizes progressivas de Raven, Questionnaire for Impulsive-Compulsive Disorders; na HPN: prova cronometrada de marcha,MMSE, prova de memória imediata da WAIS, prova de repetição de dígitos (WAIS), FAB, desenho complexo de Rey, teste de Stroop, cancelamento de letras, teste Grooved Pegboard. Os doentes com HPN foram também submetidos a estudo imagiológico. A avaliação estatística foi adaptada às características de cada um dos estudos.Resultados Distonias Primárias: encontrámos défices de função executiva, envolvendo dificuldade na mudança entre sets cognitivos, bem como correlação significativa entre as pontuações nos testes cronometrados e a gravidade dos sintomas motores. Doença de Parkinson: os doentes com DP obtiveram pontuações significativamente inferiores na FAB e em sub-testes do MMSE (memória e função visuo-espacial). A pontuação no MMSE encontrava-se significativamente correlacionada com itens da função motora não relacionados com o tremor. A disfunção da marcha, a disartria, o fenótipo não tremorígeno, a presença de alucinações e pontuação abaixo do ponto de corte na MMSE, foram factores preditivos de demência na avaliação longitudinal. A rigidez e a disartria foram factores preditivos de declínio nas funções frontais. A disfunção frontal foi factor preditivo de declínio na pontuação do MMSE. Encontrámos uma prevalência elevada de RBD nas fases iniciais da DP, que o estudo longitudinal mostrou ser factor preditivo de declínio motor, nomeadamente por agravamento da bradicinésia. Encontrámos também uma prevalência elevada de sintomas psiquiátricos, nomeadamente psicose, depressão, ansiedade, somatização e sintomas obsessivo-compulsivos. As PCI não se encontravam relacionadas com o fenótipo motor, com as complicações motoras do tratamento dopaminérgico ou com a disfunção cognitiva. HPN: os doentes com HPN e os DP apresentaram um padrão disfunção da marcha semelhante, caraterizado por passos curtos, lentidão e dificuldades de equilíbrio, sendo os sintomas mais graves na HPN. Os doentes de Parkinson com maior duração de doença, maior dose de dopaminérgicos e fenótipo motor acinético-rígido apresentaram um padrão de disfunção da marcha de gravidade semelhante ao encontrado na HPN. As alterações vasculares da substância branca, em particular as encontradas na região frontal, encontravam-se negativamente correlacionadas com a melhoria da marcha após PL. O estudo das funções cognitivas mostrou um padrão de atingimento global, com valores mais baixos na cópia do desenho complexo de Rey. Os resultados nas provas de função cognitiva não se encontravam significativamente correlacionados com os resultados na prova da marcha. A progressão na disfunção da marcha encontrava-se relacionada com o tratamento não cirúrgico, idade superior na primeira avaliação, presença de lesões da substância branca, e presença de factores de risco vascular, ao passo que não foram encontrados factores que predissessem de modo significativo o agravamento da função cognitiva. Conclusões: Os resultados dos diversos estudos, evidenciam a presença de alterações cognitivas e comportamentais nas três doenças de movimento. O padrão destas alterações e o modo como estas se relacionaram com os sintomas motores variou de doença para doença. Nas Distonias primárias, a perseveração cognitiva poderá ser o sintoma correspondente à perseveração motora própria da doença, sugerindo disfunção no circuito dorso-lateral frontoestriatal. A correlação entre a gravidade motora da doença e o resultado nos testes cognitivos cronometrados, poderá ser o efeito da relação entre bradicinésia e bradifrenia. Na Doença de Parkinson, o espectro de alterações é mais acentuado, espelhando a disseminação do processo degenerativo no SNC. Para além dos sintomas de disfunção executiva, sugerindo disfunção das tês ansas não motoras, existem sinais de disfunção cognitiva global, estas com uma influência mais significativa no desenvolvimento da demência. A relação entre os diferentes sintomas motores e cognitivos é também complexa, embora se evidencie uma dissociação significativa entre o tremor, sem relação com os sintomas não motores, e os sintomas motores não tremorígenos, relacionados com o declínio cognitivo. Enquanto que a presença de RBD parece ser um factor preditivo de agravamento motor, os sintomas psiquiátricos, também muito frequentes, apresentam uma relação menos clara com a função motora. Destes, os sintomas obsessivo-compulsivos são aqueles que com mais frequência se atribuem a disfunção do sistema fronto-estriatal, nomeadamente da ansa orbito-frontal. As PCI também não mostraram ter relação com os sintomas motores ou cognitivos. Na HPN, é patente o carácter fronto-estriatal das alterações da marcha, demonstrado tanto na sua caracterização quanto no efeito deletério das lesões vasculares da substância branca do lobo frontal na recuperação da marcha após PL. As alterações cognitivas parecem ter um padrão mais difuso, o que talvez explique a falta de correlação com os sintomas motores - esta dissociação pode ser causada quer por diferença nos mecanismos fisiopatológicos quer por presença de comorbilidades cognitivas. --------- ABSTRACT: Fronto-striatal circuits constitute a closed loop system which connects different parts of the frontal lobes to the basal ganglia. They are engaged in motor, cognitive and behavioural control. Primary Dystonia, Parkinson's Disease and Normal-Pressure Hydrocephalus are movement disorders caused by disturbance of the motor fronto-striatal circuit. The existence of cognitive and behavioural dysfunction in these movement disorders is predictable, given the functional connectivity between the several distinct loops of the circuit. Evaluation of cognitive and behavioural dysfunction in these three disorders is thus both of clinical and theoretical relevance. Objectives Our objectives were to evaluate, by clinical means, the relation between motor, cognitive and behavioural symptoms in three movement disorders with different pathophysiological backgrounds - Primary Dystonia, Parkinson's Disease and Normal-Pressure Hydrocephalus - and to analyse the study results under the theoretical framework formed by present knowledge of the fronto-estriatal system. Specific objectives: a) Primary Dystonia: executive dysfunction assessment and correlation analysis with motor dysfunction severity; b) Parkinson's Disease: 1. brief cognitive assessment in the early stages of disease, including a longitudinal analysis for determination of predictive factors for cognitive decline; 2. to investigate the relation between RBD and cognitive and motor dysfunction, including a longitudinal analysis; 3. psychiatric symptom assessment, with particular incidence on Impulse Control Disorders; c) Normal-Pressure Hydrocephalus: 1. gait dysfunction characterization and comparison with Parkinson's Disease patients; 2. determination of cognitive dysfunction profile and its relation with gait dysfunction; 3. follow-up study of cognitive and motor outcome in patients submitted and not submitted to shunt surgery. Methods: Primary Dystonia, Parkinson's Disease and Normal Pressure Hydrocephalus were diagnosed according to clinically validate criteria. Where warranted, we recruited control groups formed by healthy individuals, matched for age, sex and educational level. Patients were evaluated with instruments of direct clinical application, including motor function scales, neuropsychological tests aimed at global and executive functions and psychiatric rating scales. Tests used in Primary Dystonia: Unified Dystonia Rating Scale, Wisconsin Card Sorting Test, Stroop Test, Cube Assembly test (WAIS), Benton’s Visual Retention Test; in Parkinson's Disease: Unified Parkinson's Disease Rating Scale, Frontal Assessment Battery (FAB) , Mini-mental State Examination (MMSE), REM-sleep behavior disorder Questionnaire, Symptom Check-list 90- R, Brief Psychiatric Rating Scale, FAS (phonetic verbal fluency), semantic verbal fluency test, digit span test (WAIS), auditory verbal learning test,Stroop test, Raven's progressive Matrices, Questionnaire for Impulsive-Compulsive Disorders; in NPH: timed walking test, MMSE, immediate memory task (WAIS), digit span test (WAIS), FAB, Rey’s Complex Figure test, Stroop test, letter cancellation test, Perdue Pegboard test. NPH patients were also subjected to an imaging study. Statistics were adapted to the characteristics of each study.Results: Primary Dystonia: we found set-shifting deficits as well as significant correlation between timed neuropsychological tests and dystonia severity. Parkinson's Disease: PD patients had significantly lower scores on the FAB and on the memory and visuo-spatial tests of the MMSE; MMSE scores were significantly correlated to non-tremor motor scores; gait dysfunction and speech scores, non-tremor motor phenotype, hallucinations and scores bellow cut-off on the MMSE were predictive of dementia at follow-up; speech and rigidity scores were predictive of frontal type decline; frontal dysfunction was predictivy of decline in MMSE scores; RBD bradykinesia worsening; psychiatric symptoms were prevalent, particularly Psychosis, Depression, Anxiety, Somatisation and Obsessive-Compulsive Symptoms; Impulse Control Disorders were unrelated to motor phenotype,motor side effects of dopamine treatment and executive function; NPH: gait dysfunction was worse in NPH when compared to PD patients, although the pattern was similarly characterized by slowness, short steps and disequilibrium; PD patients whose gait disturbance was as severe as that of NPH patients were characterized by longer disease duration, predominance of non-tremor motor scores, more advanced disease stage and higher dopamine dose; frontal white matter lesions correlated negatively with improvement after LP; cognitive function assessment revealed wide spread deficits, with lower results on the drawing of the complex figure of Rey, which were not significantly correlated to gait dysfunction; older age, white matter lesions and the presence of vascular risk factors were predictive factors for motor but not cognitive function worsening. Conclusion: Results from our studies highlight the presence of cognitive and behavioural dysfunction in all three movement disorders. Symptom pattern and the relation with ovement derangement varied according to the disease. In Primary Dystonia, set-shifting difficulties could be the cognitive counterpart of motor perseveration characteristic of this disorder, suggesting dysfunction of the dorso-lateral circuit. The relation between timed tests and dystonia severity could suggest a relation between bradyphrenia and bradykinesia in Primary Dystonia. In Parkinson's Disease patients, the spectrum of non-motor symptoms is wider, probably reflecting the spread of neurodegeneration beyond the fronto-striatal circuits. While frontal type deficits predominate, suggestive of dorso-lateral and orbito-frontal dysfunction, non-frontal deficits were also apparent in the initial stages of disease, and were predictive of dementia at follow-up. The relationship between cognitive and motor symptoms is complex, although the results strongly suggest a dissociation between tremor symptoms, which bore no relation with non-motor symptoms, and non-tremor symptoms,whichwas frequent, and a predictive factor for which were related with cognitive decline. While RBD was found to be a predictive factor for bradykinesia worsening, psychiatric symptoms, which were also frequent, showed no apparent relation with motor dysfunction. Relevant to our theoretical consideration was the high prevalence of OCS, which have been attributed to orbito-frontal dysfunction. As to the particular case of ICD, we found no relation either with motor or cognitive dysfunction. The fronto-striatal nature of gait dysfunction in NPH is suggest by the clinical characterization study and by the effects of frontal white matter lesions on gait recovery after LP, whereas cognitive dysfunction presented a more diffuse pattern, which could explain the lack or relation with gait assessment results and also the different outcome on the longitudinal study - this dissociation could be caused by a real difference in pathophysiological mechanisms or, in alternative, be due to the existence of cognitive comorbidities.

Complicações em idosos submetidos a cirurgia de correcção de de hérnias da parede abdominal

RESUMO: O envelhecimento da população é um fenómeno à escala mundial, com tendência a aumentar, sendo cada vez mais os idosos e mais velhos. Esta propensão é notória nos utentes que recorrem aos cuidados de saúde. À medida que se envelhece maior vai sen-do a vulnerabilidade e riscos para a saúde, bem como a prevalência para doenças croni-cas, que se traduz num aumento de hospitalizações e consumo. As complicações ocorri-das em idosos aquando submetidos a intervenções cirúrgicas estão descritas na literatu-ra, havendo uma escassez de publicações nacionais relacionadas com o tema. O presente estudo teve por objectivo caracterizar idosos submetidos a correcção cirúrgi-ca de hérnias da parede abdominal, os procedimentos e as complicações ocorridas. O estudo, transversal e de natureza quantitativa, foi realizado no Centro Hospitalar de Lisboa Norte – Hospital Pulido Valente, e teve como critério de inclusão os indivíduos com 65 ou mais anos submetidos a correcção cirúrgica de hérnias da parede abdominal, realizadas em 2009-2010, que tiveram um período de recobro na Unidade de Cuidados Anestésicos Pós-operatórios. Para a obtenção dos dados, foram analisados os processos clínicos do Arquivo Clínico da Instituição e registada informação sobre variáveis de caracterização sócio demográfi-ca, de saúde pré, intra e pós-operatória imediata e descritivas da cirurgia. Foram avaliadas as situações de 164 indivíduos, 78.7% eram homens e 21.3% mulheres e a média de idades era de 72.4 anos e desvio padrão 5.46. Em termos de hábitos de Vida, foi possível constatar um predomínio de baixo consumo de tabaco (13.4%) e álcool (6.7%). O valor médio de co-morbilidades foi de 2.6 e desvio padrão de 1.34 sendo a maior prevalência de 3-4 co-morbilidades com 48.8%. Salienta-se que todas as mulheres da amostra apresentaram doenças. As patologias mais prevalentes são as do foro cardiovascular: Hipertensão Arterial (75.0%), Dislipidémia (35.4%) e Insuficiência Venosa Periférica (14.6%), de forma menos expressiva, mas igualmente relevante a Diabetes Mellitus (23.8%). Nos mais idosos [75 ou mais], verificou-se uma expressivi-dade Hipertrofia benigna da próstata (18.2%). Das cirurgias ocorridas predominou a correcção cirúrgica de Hérnia Inguinal.Das complicações identificadas prevaleceu a dor (97.6%). A hipotermia (34.8%), HTA (24.4%) e bradicárdia (14.6%) encontram-se entre as complicações mais determinantes. Verificaram-se diferenças com significado estatístico entre os dois grupos etários consi-derados nas complicações bradicárdia (p=0.021) e a saturação de oxigénio <90% (p = 0.006), hemorragia (p=0.036) e retenção urinária (p = 0.038). Neste estudo constata-se que a cirúrgica de hérnias da parede abdominal em idosos é uma realidade prevalente. Dos factores que possam estar associados a propensão para complicações pós-cirúrgicas, a idade e a presença de co-morbilidade controlada não revelaram ter influência. Também os tempos de cirurgia e de anestesia não revelaram influências no surgimento de complicações. A monitorização dos sinais vitais deve ser constante, desde o período pré-operatório imediato de forma a permitir aos profissionais de saúde identificar uma propensão para vulnerabilidade, com vantagem em ser apre-sentado sob a forma de score. Este manifestou diferenças significativas a nível dos dois grupos etários considerados (p=0.001). Este score, vai possibilitar sinalizar quais os idosos com maior susceptibilidade de ocorrência de complicações.------------------ABSTRACT:Population aging has become a worldwide phenomenon with tendency to increase. This is particularly evident due to the amount of elderly that attend the medical services. As one gets older, more vulnerable and more risks to one’s health. Also chronic diseas-es are more likely to exist which lead to more hospitalizations and increase of consuma-bles. The complications after a surgery in older people are well documented in international scientific studies, however national studies are still lacking. The present study aims to characterize elderly patients after abdominal hernia surgical correction, the procedures and complications detected. This transversal and quantitative nature like study, was held in the Centro Hospitalar Lisboa-Norte – Hospital Pulido Valente, and as inclusive criteria where patients with more than 65 or more years old, who undergone abdominal hernia surgical correction surgery in 2009-2010 and had the post-operation on the Unidade de Cuidados Anestésicos Pós-Operatorios. Data from the clinical files from the archive of the hospital where analyzed. Information was taken regarding social demographic variables; before, during and immediately after surgery variables and also descriptive of the surgery itself. Were evaluated 164 individuals, 78, 7% of which were men and 21, 3% women with an average age of 72, 4 years and standard deviation 5.46. Life habits analyzed detected low consumption of tobacco (13, 4%) and alcohol (6, 7%). The average of co-morblity was 2, 6 and standard deviation 1.34. The biggest prevalence of 3-4 co-morbilities was 48, 8%. Important to notice that, all women from the study presented illnesses. The illnesses more frequent were cardiovascular: High Blood Pressure (75%), Dyslipidemia (35, 4%), Deep Venous Insufficiency (14, 6%), less significant but also relevant, Diabetes Melli-tus (23, 8%). In the older (75 or more), was noticed Benign Prostatic (18, 2%). In the surgeries verified, the abdominal hernia correction was more frequent. From all thecomplications identified, pain was 97, 6%, Hypothermia 34, 8%, high Blood Pressure 24, 4% and Bradycardia 14, 6%, were higher prevalence. Was seen differences in the statistic meaning of the two groups in the Bradycardia com-plications (p=0.021), and the oxygen saturation < 90% (p=0.006), bleeding (p=0,036) and urine retention (p=0,038). In the present study it is evident that the abdominal hernia surgical correction in older population is a common procedure. Of all the factors that might be related with post-operatory complications, age and the presence of controlled co-morbility didn’t reveal relevant. Also, surgical times and duration of anesthesia didn´t seem to be related to complications incidence. Monitoring the vital signs must be constant since the immedi-ate post-operatory to ensure that the professionals can identify any possible vulnerabil-ity, presenting it in a score like way. The score has shown meaningful differences be-tween the two age groups analyzed (p=0,001). This score allows identifying which pa-tients are more likely to suffer complications.

Improved polymeric medical devices for active substances delivery

The work presented in this thesis was developed in collaboration with a Portuguese company, BeyonDevices, devoted to pharmaceutical packaging, medical technology and device industry. Specifically, the composition impact and surface modification of two polymeric medical devices from the company were studied: inhalers and vaginal applicators. The polyethylene-based vaginal applicator was modified using supercritical fluid technology to acquire self-cleaning properties and prevent the transport of bacteria and yeasts to vaginal flora. For that, in-situ polymerization of 2-substituted oxazolines was performed within the polyethylene matrix using supercritical carbon dioxide. The cationic ring-opening polymerization process was followed by end-capping with N,N-dimethyldodecylamine. Furthermore, for the same propose, the polyethylene matrix was impregnated with lavender oil in supercritical medium. The obtained materials were characterized physical and morphologically and the antimicrobial activity against bacteria and yeasts was accessed. Materials modified using 2-substituted oxazolines showed an effective killing ability for all the tested microorganisms, while the materials modified with lavender oil did not show antimicrobial activity. Only materials modified with oligo(2-ethyl-2-oxazoline) maintain the activity during the long term stability. Furthermore, the cytotoxicity of the materials was tested, confirming their biocompatibilty. Regarding the inhaler, its surface was modified in order to improve powder flowability and consequently, to reduce powder retention in the inhaler´s nozzle. New dry powder inhalers (DPIs), with different needle’s diameters, were evaluated in terms of internal resistance and uniformity of the emitted dose. It was observed that they present a mean resistance of 0.06 cmH2O0.5/(L/min) and the maximum emitted dose obtained was 68.9% for the inhaler with higher needle´s diameter (2 mm). Thus, this inhaler was used as a test and modified by the coating with a commonly-used force control agent, magnesium stearate, dried with supercritical carbon dioxide (scCO2) and the uniformity of delivered dose tests were repeated. The modified inhaler showed an increase in emitted dose from 68.9% to 71.3% for lactose and from 30.0% to 33.7% for Foradil.

Enrichment of a PHA producing microbial community in a continuous bioreactor setup

Polyhydroxyalkanoates (PHAs) are biosynthetic polyesters, biodegradable and biocompatible making them of great interest for industrial purposes. The use of low value substrates with mixed microbial communities (MMC) is a strategy currently used to decrease the elevated PHA production costs. PHA production process requires an important step for selection and enrichment of PHA-storing microorganisms which is usually carried out in a Sequencing Batch Reactor (SBR). The aim of this study was to optimize the PHA accumulating culture selection stage using a 2-stage Continuous Stirrer Tank Reactor (CSTR) system. The system was composed by two separate feast and famine bioreactors operated continuously, mimicking the feast and famine phases in a SBR system. Acetate was used as carbon source and biomass seed was highly enriched in Plasticicumulans acidivorans obtained from activated sludge. The system was operated under two different sets of conditions (setup 1 and 2), maintaining a system total retention time of 12 hours and an OLR of 2.25 Cmmol/L.h-1. An average PHB-content of 3.3 % wt was obtained in setup 1 and 4.8% wt in setup 2. Several other experiments were performed in order to better understand the continuous system behaviour, using biomass from the continuous system. With the fed-batch experiment a maximum of 8.1% PHB was stored and the maximum substrate uptake and specific growth rates obtained in the growth experiment (1.15 Cmol Cmol-1.h-1 and 0.53 Cmol Cmol-1.h-1) were close to the ones from continuous system (1.12 Cmol Cmol-1.h-1 and 0.59 Cmol Cmol-1.h-1). The microbial community was characterized trough microscopic visualization, Denaturing Gradient Gel Electrophoresis (DGGE) analysis and Fluorescent in situ hybridization (FISH). The last studied performed mimicked the continuous system by building up a SBR system with all the same operational conditions while adding an extra acetate dosage during the 12 h cycle, simulating the substrate passing from the feast to the famine reactors under continuous operation. It was shown that possibly the continuous system was not able to efficiently select for PHB storing organisms under the operational conditions imposed, although the selected culture was capable of consuming the substrate and grow fast. This main conclusion might have resulted from two major factors affecting the system performance: the ammonium concentration in the Feast reactor and the amount of substrate leaching from the Feast to the Famine reactor.

The effect of key process operational conditions on enhanced biological phosphorus removal from wastewater

Enhanced biological phosphorus removal (EBPR) is the most economic and sustainable option used in wastewater treatment plants (WWTPs) for phosphorus removal. In this process it is important to control the competition between polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs), since EBPR deterioration or failure can be related with the proliferation of GAOs over PAOs. This thesis is focused on the effect of operational conditions (volatile fatty acid (VFA) composition, dissolved oxygen (DO) concentration and organic carbon loading) on PAO and GAO metabolism. The knowledge about the effect of these operational conditions on EBPR metabolism is very important, since they represent key factors that impact WWTPs performance and sustainability. Substrate competition between the anaerobic uptake of acetate and propionate (the main VFAs present in WWTPs) was shown in this work to be a relevant factor affecting PAO metabolism, and a metabolic model was developed that successfully describes this effect. Interestingly, the aerobic metabolism of PAOs was not affected by different VFA compositions, since the aerobic kinetic parameters for phosphorus uptake, polyhydroxyalkanoates (PHAs) degradation and glycogen production were relatively independent of acetate or propionate concentration. This is very relevant for WWTPs, since it will simplify the calibration procedure for metabolic models, facilitating their use for full-scale systems. The DO concentration and aerobic hydraulic retention time (HRT) affected the PAO-GAO competition, where low DO levels or lower aerobic HRT was more favourable for PAOs than GAOs. Indeed, the oxygen affinity coefficient was significantly higher for GAOs than PAOs, showing that PAOs were far superior at scavenging for the often limited oxygen levels in WWTPs. The operation of WWTPs with low aeration is of high importance for full-scale systems, since it decreases the energetic costs and can potentially improve WWTP sustainability. Extended periods of low organic carbon load, which are the most common conditions that exist in full-scale WWTPs, also had an impact on PAO and GAO activity. GAOs exhibited a substantially higher biomass decay rate as compared to PAOs under these conditions, which revealed a higher survival capacity for PAOs, representing an advantage for PAOs in EBPR processes. This superior survival capacity of PAOs under conditions more closely resembling a full-scale environment was linked with their ability to maintain a residual level of PHA reserves for longer than GAOs, providing them with an effective energy source for aerobic maintenance processes. Overall, this work shows that each of these key operational conditions play an important role in the PAO-GAO competition and should be considered in WWTP models in order to improve EBPR processes.

NHL 3.5 mortars with scrap tire rubber

The use of wastes and industrial by-products as building materials is an important issue in order to decrease costs with waste management and the embodied energy of building products. Scrap tire rubber has been studied as aggregate for cementitious materials. Natural hydraulic limes are natural binders with particular characteristics of both air and hydraulic binders. Their specifications became stricter with the last version of EN 459-1:2010. In this study scrap tire rubber was used as additional aggregate of mortars, based on NHL3.5 and natural sand. Different particle size fractions and proportions of scrap tire rubber were used: a mix obtained almost directly from industry (only after sieving for preparation of particle sizes similar to mortar aggregate) and separated fine, medium and coarse fractions; 0%, 18%, 36% and 54% weight of binder, corresponding to 2.5%, 5% and 7.5% weight of sand. The influence of the rubbers´ additions on the mortars´ fresh state, mechanical and physical performance is presented, namely by flow table consistency, water retention, fresh bulk density, dynamic elasticity modulus, flexural and compressive strength, open porosity and bulk density, capillary absorption, drying and thermal conductivity. The use of the rubber mix coming from the waste tire industry seems advantageous and may open possibilities for use as raw material by the mortars industry.

Management consulting labs Galp loyalty

The main objective of this project was to investigate methods to create a new loyalty approach for Galp Energia in order to improve customer retention and reduce churn, related with the expansion of hypermarket chains’ in the Fuel Retail Market and the country’s economical situation. The team carried out on-spot surveys and focus groups, researched loyalty programs’ best practices, analyzed peers practices and the company’s past performance in order to find important customer insights. These were used to develop the final recommendations resulting in a new paradigm to the group’s loyalty approach alongside incremental improvements to the current loyalty solutions.

Impact of carbon/nitrogen feeding strategy on polyhydroxyalkanoates production using mixed microbial cultures

Polyhydroxyalkanoates (PHA) production using mixed microbial cultures (MMC) requires a multi-stage process involving the microbial selection of PHA-storing microorganisms, typically operated in sequencing batch reactors (SBR), and an accumulation reactor. Since low-cost renewable feedstocks used as process feedstock are often nitrogen-deficient, nutrient supply in the selection stage is required to allow for microbial growth. In this context, the possibility to uncouple nitrogen supply from carbon feeding within the SBR cycle has been investigated in this study. Moreover, three different COD:N ratios (100:3.79, 100:3.03 and 100:2.43) were tested in three different runs which also allowed the study of COD:N ratio on the SBR performance. For each run, a synthetic mixture of acetic and propionic acids at an overall organic load rate of 8.5 gCOD L-1 d-1 was used as carbon feedstock, whereas ammonium sulfate was the nitrogen source in a lab-scale sequence batch reactor (SBR) with 1 L of working volume. Besides, a sludge retention time (SRT) of 1 d was used as well as a 6 h cycle length. The uncoupled feeding strategy significantly enhanced the selective pressure towards PHA-storing microorganisms, resulting in a two-fold increase in the PHA production (up to about 1.3 gCOD L-1). A high storage response was observed for the two runs with the COD:N ratios (gCOD:gN) of 100:3.79 and 100:3.03, whereas the lowest investigated nitrogen load resulted in very poor performance in terms of polymer production. In fact, strong nitrogen limitation caused fungi to grow and a very poor storage ability by microorganisms that thrived in those conditions. The COD:N ratio also affected the polymer composition, indeed the produced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) showed a variable HV content (1-20 %, w/w) among the three runs, lessening as the COD:N increased. This clearly suggests the possibility to use the COD:N ratio as a tool for tuning polymer properties regardless the composition of the feedstock.

Understanding churn and its reasons: The GuestU case

In the age of computerisation, entrepreneurs around the world aim to revolutionise their field with ground-breaking ICTs. GuestU is one of those offering mobile application development to small and medium-sized tourism enterprises. To assure the young start-ups steady growth this paper aims to identify reasons for the high customer churn risk. Primary data is used to analyse end-user behaviour and particularly the success of acquisition and activation. Results show troubling download quantities as well as retention rates leading to the recommendations for GuestU to incentivise and guide their customers in increasing promotion for the applications.

Development of paper transistor with memory effect

This work will discuss the use of different paper membranes as both the substrate and dielectric for field-effect memory transistors. Three different nanofibrillated cellulose membranes (NFC) were used as the dielectric layer of the memory transistors (NFC), one with no additives, one with an added polymer PAE and one with added HCl. Gallium indium zinc oxide (GIZO) was used as the device’s semiconductor and gallium aluminium zinc oxide (GAZO) was used as the gate electrode. Fourier transform infrared spectroscopy (FTIR) was used to access the water content of the paper membranes before and after vacuum. It was found that the devices recovered their water too quickly for a difference to be noticeable in FTIR. The transistor’s electrical performance tests yielded a maximum ION/IOFF ratio of around 3,52x105 and a maximum subthreshold swing of 0,804 V/decade. The retention time of the dielectric charge that grants the transistor its memory capabilities was accessed by the measurement of the drain current periodically during 144 days. During this period the mean drain current did not lower, leaving the retention time of the device indeterminate. These results were compared with similar devices revealing these devices to be at the top tier of the state-of-the-art.