Toxicity identification evaluation of polyester resin manufacturing wastewater

Orientador: Lucia Regina DurrantTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: Os processos industriais são geradores de uma ampla variedade de contaminantes que estão presentes nas águas residuarias. A seleção de processos de tratamento baseia-se nas características do efluente a ser tratado. Neste trabalho investigou-se um efluente tóxico da fabricação de resinas de poliéster. Existem poucas informações na literatura sobre este tipo de água residuaria. Procedeu-se a caracterização do efluente, efetuando-se a avaliação e identificação de constituintes tóxicos presentes no mesmo por meio de uma abordagem orientada por toxicidade. Foi utilizado bioensaio respirometrico em lodo ativado para avaliar a toxicidade do efluente bruto. Então, foram efetuados tratamentos físicos e químicos para fracionamento do efluente, e apos cada um deles, realizou-se o mesmo bioensaio. Dessa maneira, avaliou-se qual técnica de fracionamento foi a mais efetiva na redução da toxicidade. A maior redução de toxicidade foi observada apos o fracionamento do efluente por arraste com ar em pH 11 (62,5 %). Este resultado demonstrou que uma fração significativa da toxicidade do efluente para lodos ativados era causada por compostos orgânicos volatilizados em pH 11. Isso indica que o tratamento do efluente por arraste com ar em pH básico pode ter impacto positivo em um tratamento biológico aeróbio subseqüente. Uma vez determinado o tipo de compostos no efluente que provocam efeitos tóxicos (Compostos Organicos Volateis - COVs), procedeu-se a esforços analíticos visando a identificação dos mesmos. Analises por headspace do efluente por cromatografia gasosa e espectrometria de massa identificaram a presença de aldeidos insaturados (congeneres de acroleina). Tais compostos tinham relacao direta com o efeito tóxico observado. Foram também realizados bioensaios utilizando microrganismos anaerobios. Para tanto, mediu-se o volume de gas produzido por uma biomassa anaerobia em contato com o efluente bruto e com o efluente fracionado por arraste com ar em pH 11. Não se observou redução na toxicidade do efluente mesmo com este fracionamento. Comparando-se esses resultados aos obtidos com lodo ativados, foi verificado que os compostos removidos por arraste com ar em pH 11 não apresentaram o mesmo grau de toxicidade para esta biomassa anaerobia. Tais resultados indicam que a utilização de processo de tratamento biológico anaerobio seria uma opção adequada para a condução de futuros estudos de tratabilidade deste efluente. Os resultados obtidos neste trabalho de avaliação e identificação de toxicidade em efluente da fabricação de resinas de poliéster ratificam a abordagem utilizada como uma valorosa ferramenta na caracterização de efluentes industriais tóxicos, principalmente nos casos onde não se encontram disponíveis informações especificas relacionadas ao efluente estudadoAbstract: Industrial processes generate a vast range of contaminants that are present in wastewaters. Treatment process selection is based on wastewater characteristics. In this work a toxic polyester resin manufacturing wastewater was investigated. Specific literature on this kind of wastewater is rare. The characterization of this wastewater was conducted, evaluating and identifying toxicity by applying a toxicity-oriented approach. An activated sludge respirometric bioassay was used to assess effluent toxicity. Then, physical and chemical treatments were performed for effluent fractionation. After each fractionation, the same bioassay was conducted. In this way, it was assessed which fractionation technique was the most effective in reducing effluent toxicity. The greater toxicity reduction was observed after effluent fractionation with air stripping in pH 11 (62.5 %). This result showed that a significant fraction of wastewater toxicity for activated sludge was caused by organic compounds volatilized in pH 11. This indicates that effluent treatment by air stripping in basic pH could have a positive impact in a conjugated aerobic biological treatment. Once the type of compounds causing wastewater toxicity has been determined (Volatile Organic Compounds ¿ VOCs), analytical efforts aiming the identification of these compounds were made. Wastewater headspace gas chromatographic analyses coupled with mass spectrometry identificated the presence of a,ß-unsaturated aldehydes (acrolein congeners). These compounds were directly related to the observed toxic effect. Bioassays using anaerobic microorganisms were also conducted. To that purpose, the volume of gas produced by an anaerobic biomass in contact with the baseline effluent and with the fractionated effluent by air stripping in pH 11 was measured. No toxicity reduction was observed with this fractionation. By comparing this result with the one obtained with the respirometric bioassay, it was found that the compounds removed by air stripping in pH 11 did not inhibit this kind of biomass in the same degree which they inhibited activated sludge. This indicates that the use of an anaerobic treatment process would be an adequate option for conducting future treatability studies in this wastewater. The results obtained in this research of toxicity identification evaluation of a polyester resin manufacturing effluent confirm that the toxicity-oriented approach is a valuable tool for the characterization of toxic industrial wastewaters, especially in cases when specific information related to the studied wastewater is lackingDoutoradoDoutor em Ciência de Alimento

A multidetector tomography protocol for follow-up of endovascular aortic aneurysm repair

OBJECTIVE: The purpose of this study was to improve the use of 64-channel multidetector computed tomography using lower doses of ionizing radiation during follow-up procedures in a series of patients with endovascular aortic aneurysm repair. METHODS: Thirty patients receiving 5 to 29 months of follow-up after endovascular aortic aneurysm repair were analyzed using a 64-channel multidetector computed tomography device by an exam that included pre-and postcontrast with both arterial and venous phases. Leak presence and type were classified based on the exam phase. RESULTS: Endoleaks were identified in 8/30 of cases; the endoleaks in 3/8 of these cases were not visible in the arterial phases of the exams. CONCLUSION: The authors conclude that multidetector computed tomography with pre-contrast and venous phases should be a part of the ongoing follow-up of patients undergoing endovascular aortic aneurysm repair. The arterial phase can be excluded when the aneurism is stable or regresses. These findings permit a lower radiation dose without jeopardizing the correct diagnosis of an endoleak

Comparison of reduction of edema after rest and after muscle exercises in treatment of chronic venous insufficiency

<p>Abstract</p> <p>Aim</p> <p>The aim of this work was to compare the reduction in edema obtained in the conservative treatment of phlebopathies after resting and after performing a muscle exercise program in the Trendelenburg position.</p> <p>Methods</p> <p>Twenty-eight limbs of 24 patients with venous edema of distinct etiologies and classified as between C3 and C5 using CEAP classification. Volumetric evaluation by water displacement was carried out before and after resting in the Trendelenburg position and after performing programmed muscle exercises 24 hours later under identical conditions of time, position and temperature. For the statistical analysis the paired t-test was used with an alpha error of 5% being considered acceptable.</p> <p>Results</p> <p>The average total volume of the lower limbs was 3,967.46 mL. The mean reduction in edema obtained after resting was 92.9 mL, and after exercises it was 135.4 mL, giving a statistically significant difference (p-value = 0.0007).</p> <p>Conclusion</p> <p>In conclusion, exercises are more efficient to reduce the edema of lower limbs than resting in the Trendelenburg position.</p

Lower limb edema after great saphenous vein harvesting to be used as graft in myocardial revascularization

CONTEXTO: A revascularização do miocárdio utilizando-se a veia safena magna ainda é procedimento cirúrgico bastante realizado na atualidade. O edema que surge no membro inferior operado causa grande desconforto e necessita ser melhor estudado. OBJETIVOS: Caracterizar o edema de membro inferior secundário a exérese da veia safena magna pela técnica de incisões escalonadas para sua utilização como enxerto venoso na revascularização do miocárdio. MÉTODOS: Foram selecionados aleatoriamente 44 indivíduos submetidos a exérese de veia safena magna para revascularização miocárdica há mais de 3 meses. Excluíram-se fatores que pudessem interferir na formação de edema dos membros inferiores. Foram avaliados por volumetria e perimetria maleolares ambos os membros inferiores. Considerou-se como presença de edema significativo a diferença de volume maior que 50 mL e maior de 2 cm em relação ao membro não-operado. Para a análise estatística foram empregados o teste do qui-quadrado, teste exato de Fisher, teste t de Student e o teste de McNemar. O nível de significância adotado foi de 5% (a = 0,05). RESULTADOS: Encontraram-se diferenças estatisticamente significativas (p < 0.05) entre os membros operados e os não-operados, sendo 56,8% com volume maior que 50 mL e 31,9% com perímetro maleolar maior que 2 cm. Não se encontrou associação entre a presença do edema e características da amostra ou da cirurgia e de intercorrências clínicas perioperatórias ou tardias. CONCLUSÕES: Pacientes submetidos a ressecções de veia safena magna para sua utilização como ponte coronariana poderão apresentar edema no membro associado.BACKGROUND: Myocardial revascularization using the great saphenous vein is still a very common surgical procedure. The edema that occurs in the operated leg causes much discomfort and requires further studies. OBJECTIVES: To describe lower limb edema secondary to great saphenous vein harvesting using the bridge technique for use as venous graft in myocardial revascularization. METHODS: Forty-four individuals previously submitted to great saphenous vein harvesting for myocardial revascularization more than 3 months before were randomly selected. Patients with factors that might interfere with formation of lower limb edema were excluded. Both operated and non-operated legs were evaluated by volumetry and perimetry of the malleolar region. Differences greater than 50 mL or higher than 2 cm between the operated and the contralateral leg were considered as presence of significant edema. Chi-square, Fisher&#8217;s, McNemar&#8217;s and Student&#8217;s t tests were used for statistical analysis. Significance level was set at 5% (a = 0.05). RESULTS: Statistically significant differences (p < 0.05) were found between operated and contralateral legs, with 56.8% of the individuals having a difference in volume greater than 50 mL and 31.9% having a difference in malleolar region perimeter greater than 2 cm. There was no association between presence of edema and sample characteristics, surgery, perioperative or late clinical complications. CONCLUSIONS: Patients submitted to resection of the great saphenous vein for coronary artery bypass grafting may evolve with edema of the operated leg

Carotid stenosis: what is the high-risk population?

OBJECTIVE: Prevention is the best treatment for cerebrovascular disease, which is why early diagnosis and the immediate treatment of carotid stenosis contribute significantly to reducing the incidence of stroke. Given its silent nature, 80% of stroke cases occur in asymptomatic individuals, emphasizing the importance of screening individuals with carotid stenosis and identifying high-risk groups for the disease. The aim of this study was to determine the prevalence and the most frequent risk factors for carotid stenosis. METHODS: A transversal study was conducted in the form of a stroke prevention campaign held on three nonconsecutive Saturdays. During the sessions, carotid stenosis diagnostic procedures were performed for 500 individuals aged 60 years or older who had systemic arterial hypertension and/or diabetes mellitus and/or coronary heart disease and/or a family history of stroke. RESULTS: The prevalence of carotid stenosis in the population studied was 7.4%, and the most frequent risk factors identified were mean age of 70 years, carotid bruit, peripheral obstructive arterial disease, coronary insufficiency and smoking. Independent predictive factors of carotid stenosis include the presence of carotid bruit or peripheral obstructive heart disease and/or coronary insufficiency. CONCLUSIONS: The population with peripheral obstructive heart disease and carotid bruit should undergo routine screening for carotid stenosis

Randomized trial of radiofrequency ablation versus conventional surgery for superficial venous insufficiency: if you don’t tell, they won’t know

OBJECTIVES: This study compared radiofrequency ablation versus conventional surgery in patients who had not undergone previous treatment for bilateral great saphenous vein insufficiency, with each patient serving as his own control. METHOD: This was a randomized controlled trial that included 18 patients and was carried out between November 2013 and May 2015. Each of the lower limbs of each patient was randomly assigned to undergo either radiofrequency ablation or conventional surgery. Clinical features (hyperpigmentation, hematoma, aesthetics, pain, skin burn, nerve injury, and thrombophlebitis) were evaluated at one week, one month, and six months postoperatively. Hemodynamic assessments (presence of resection or occlusion of the great saphenous vein and recurrent reflux in the sapheno-femoral junction and in the great saphenous vein) were performed at one month, six months, and 12 months postoperatively. The independent observer (a physician not involved in the original operation), patient, and duplex ultrasonographer were not made aware of the treatment done in each case. Clinicaltrials.gov: NCT02588911. RESULTS: Among the clinical variables analyzed, only the aesthetic evaluation by the physicians was significant, with radiofrequency ablation being considered better than conventional surgery (average, 0.91 points higher: standard deviation: 0.31; 95% confidence interval: -1.51, -0.30; p=0.003). However, in our study, we observed primary success rates of 80% for radiofrequency ablation and 100% for conventional surgery. CONCLUSIONS: If the physician is not required to inform the patient as to the technique being performed, the patient will not be able to identify the technique based on the signs and symptoms. Our study revealed that both techniques led to high levels of patient satisfaction, but our results favor the choice of conventional surgery over radiofrequency ablation, as patients who underwent conventional surgery had better hemodynamic assessments