269 research outputs found

    Enzymatic surface hydrolysis of PET enhances bonding in PVC coating

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    The effect of polyesterase preparations from Thermomyces lanuginosus and Beauveria brongniartii on the hydrophilicity of PET materials was assessed. As a result of polyesterase treatment the hydrophilicity of PET fabrics was increased by up to 8 cm in terms of rising height with increases in surface tension from 6.2 mNm (heat-inactivated control samples) to above 8 mNm. Both enzymes were able to increase the amount of hydroxyl groups on PET from 90 to a maximum of 182 mmol kg-1, while only the B. brongniartii polyesterase released significant amounts of terephthalic acid from PET. Enzymatic surface hydrolysis of PET increased the bonding strength in PVC coating to 13.40 daN 5cm-1 using 0.5% adhesive compared to 11.5 daN 5cm-1 obtained without enzyme pretreatment and 6% of adhesive.The research was financed by the SFG, the FFG, the city of Graz and the province of Styria and by European Commission within the project GRD 2000-30110 Biosynte

    Polymerization study of the aromatic amines generated by the biodegradation of azo dyes using the laccase enzyme

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    Four different azo dyes were decolorized (color reduction >90%) by bacteria isolated from a textile wastewater effluent. Dye decolorizing was carried out under microaerobic conditions until completion, after which the aromatic amine concentration was determined. A laccase from Myceliophthora thermophila was used to catalyze coupling reactions of the aromatic amines produced from decolorizing the dyes. The reaction was carried out with stirring (100 rpm) in a weak acidic buffer solution (pH 5.0) at 45 °C for 3 days. The presence of aromatic amines in the samples after bacterial decolorizing confirmed the azo bond was reduced in the process. In addition, the UV–vis spectrum was shifted significantly after the sequential bacterial-laccase treatment also indicating a chemical transformation of the dyes. After laccase treatment the solutions formed colored soluble and precipitated products. The particles sizes making up the precipitates formed after laccase treatment varied between 105 and 483 nm as determined by Photon Correlation Spectroscopy (PCS). The laccase treatment also reduced the COD of the dye solutions by ∼20%. We show that successive bacterial-laccase treatment is effective in decolorized azo dyes by reduction of the azo bonds, and promoting coupling reactions between the aromatic amines formed. Promoting coupling reactions between the aromatic amines using enzymes may prove useful for the physical removal and reuse of these amines.The authors would like to thank the Brazilian Foundation Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior of the Ministry of Education (CAPES) and the National Counsel for Technological and Scientific Development (CNPq) for providing grants to Elisangela Franciscon

    Desfechos psicológicos em longo prazo após alta da terapia intensiva

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    Objective: To investigate the longterm psychological outcome in survivors of critical illness after intensive care unit discharge. Methods: A prospective cohort of survivors admitted to a mixed intensive care unit between January and September 2010 was evaluated six months and five years after hospital discharge. The Dementia Rating Scale-2, the Hospital Anxiety and Depression Scale, the Posttraumatic stress syndrome 14-questions inventory, the Euro Quality of Life 5 Dimensions (EQ-5-D), and the Visual Analogue Scale (EQ VAS) were assessed at both follow-up periods. Results: Of 267 patients, 25 patients were evaluated at 6 months after discharge (62 ± 16 years); 12 (48%) presented cognitive impairment, 6 (24%) anxiety, 4 (16%) depression, and 4 (16%) post-traumatic stress disorder. Among those re-evaluated five years after discharge (n = 17; 65 ± 15 years), the frequency of cognitive impairment dropped from 8 (47%) to 3 (18%) (p = 0.063), due to improvement in these patients over time, and other patients did not acquire any dysfunction after discharge. At five years after discharge, only two patients (12%) reported anxiety, and none had depression or post-traumatic stress disorder. No differences were found between the six-month and five-year follow-ups regarding EQ-5-D and EQ VAS. Conclusion: Survivors do not show a progressive decline in cognitive function or quality of life within five years after intensive care unit discharge. Psychopathological symptoms tend to decrease with time.Objetivo: Investigar o desfecho psicológico em longo prazo em sobreviventes de doenças críticas, após alta da unidade de terapia intensiva. Métodos: Avaliou-se coorte prospectiva de pacientes sobreviventes após admissão a uma unidade de terapia intensiva mista entre janeiro e setembro de 2010, 6 meses e 5 anos após a alta hospitalar. Aplicaram-se em todos os momentos as seguintes escalas: Dementia Rating Scale-2, Hospital Anxiety and Depression Scale, Post-Traumatic Stress Syndrome 14-Questions Inventory, Euro Quality of Life 5 Dimensions (EQ-5-D) e Visual Analogue Scale (EQ VAS). Resultados: Dentre 267 pacientes, 25 foram avaliados após 6 meses (idade: 62 ± 16 anos). Aos 6 meses, 48% apresentavam comprometimento cognitivo; 24% ansiedade, 16% depressão e 16% transtorno de estresse pós-traumático. Foram reavaliados 5 anos após a alta 17 pacientes, com idade: 65 ± 15 anos. Dentre eles, a frequência de comprometimento cognitivo caiu de 47% para 18% (p = 0,063), em razão da melhora destes pacientes ao longo do tempo e do não surgimento desta condição em outros pacientes após a alta. Ainda após 5 anos, apenas 12% da amostra relatou ansiedade, e nenhum tinha depressão ou transtorno de estresse pós-traumático. Não se encontraram diferenças em termos das escalas EQ-5-D e EQ VAS entre as avaliações após 6 meses e 5 anos. Conclusão: Os sobreviventes não apresentaram declínio progressivo da função cognitiva ou da qualidade de vida dentro de 5 anos após a alta da unidade de terapia intensiva. Os sintomas psicopatológicos tenderam a diminuir com o tempo.info:eu-repo/semantics/publishedVersio

    Specificities of a chemically modified laccase from trametes hirsuta on soluble and cellulose-bound substrates

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    Laccases could prevent fabrics and garments from re-deposition of dyes during washing and finishing processes by degrading the solubilized dye. However, laccase action must be restricted to solubilized dye molecules thereby avoiding decolorization of fabrics. Chemical modification of enzymes can provide a powerful tool to change the adsorption behaviour of enzymes on water insoluble polymers. Polyethylene glycol (PEG) was covalently attached onto a laccase from Trametes hirsuta. Different molecular weights of the synthetic polymer were tested in terms of adsorption behaviour and retained laccase activity. Covalent attachment of PEG onto the laccase resulted in enhanced enzyme stability while with increasing molecular weight of attached PEG the substrate affinity for the laccase conjugate decreased. The activity of the modified laccases on fibre bound dye was drastically reduced decreasing the adsorption of the enzyme on various fabrics. Compared to the 5 kDa PEG laccase conjugate (K/S value 47.60

    Treatment planning systems dosimetry auditing project in Portugal

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    BACKGROUND AND PURPOSE: The Medical Physics Division of the Portuguese Physics Society (DFM_SPF) in collaboration with the IAEA, carried out a national auditing project in radiotherapy, between September 2011 and April 2012. The objective of this audit was to ensure the optimal usage of treatment planning systems. The national results are presented in this paper. MATERIAL AND METHODS: The audit methodology simulated all steps of external beam radiotherapy workflow, from image acquisition to treatment planning and dose delivery. A thorax CIRS phantom lend by IAEA was used in 8 planning test-cases for photon beams corresponding to 15 measuring points (33 point dose results, including individual fields in multi-field test cases and 5 sum results) in different phantom materials covering a set of typical clinical delivery techniques in 3D Conformal Radiotherapy. RESULTS: All 24 radiotherapy centers in Portugal have participated. 50 photon beams with energies 4-18 MV have been audited using 25 linear accelerators and 32 calculation algorithms. In general a very good consistency was observed for the same type of algorithm in all centres and for each beam quality. CONCLUSIONS: The overall results confirmed that the national status of TPS calculations and dose delivery for 3D conformal radiotherapy is generally acceptable with no major causes for concern. This project contributed to the strengthening of the cooperation between the centres and professionals, paving the way to further national collaborations

    Polymerization of lignosulfonates by the laccase-HBT (1-hydroxybenzotriazole) system improves dispersibility

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    The ability of laccases from Trametes villosa (TvL), Myceliophthora thermophila (MtL), Trametes hirsuta (ThL) and Bacillus subtilis (BsL) to improve the dispersion properties of calcium lignosulfonates 398 in the presence of HBT as a mediator was investigated. Size exclusion chromatography showed an extensive increase in molecular weight of the samples incubated with TvL and ThL by 107% and 572% from 28400 Da after 17 h of incubation, respectively. Interestingly, FTIR spectroscopy, 13C NMR and Py-GC/MS analysis of the treated samples suggested no substantial changes in the aromatic signal of the lignosulfonates, a good indication of the ability of TvL/ThL-HBT systems to limit their effect on functional groups without degrading the lignin backbone. Further, the enzymatic treatments led to a general increase in the dispersion properties, indeed a welcome development for its application in polymer blends.Financial support from the BIORENEW EU-project (NMP2-CT-2006-26456), Austrian Academic Exchange Programme (OEAD) and the Spanish projects BIO2007-28720-E, BIO2008-01533, and AGL2008-00709 is acknowledged

    Polymerisation of lignosulfonates by the laccase-HBT (1-hydroxybenzotriazole) system improves dispersibility

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    Prasetyo, Endry Nugroho et al.--The ability of laccases from Trametes villosa (TvL), Myceliophthora thermophila (MtL), Trametes hirsuta (ThL) and Bacillus subtilis (BsL) to improve the dispersion properties of calcium lignosulfonates 398 in the presence of HBT as a mediator was investigated. Size exclusion chromatography showed an extensive increase in molecular weight of the samples incubated with TvL and ThL by 107% and 572% from 28400 Da after 17 h of incubation, respectively. Interestingly, FTIR spectroscopy, 13C NMR and Py-GC/MS analysis of the treated samples suggested no substantial changes in the aromatic signal of the lignosulfonates, a good indication of the ability of TvL/ThL-HBT systems to limit their effect on functional groups without degrading the lignin backbone. Further, the enzymatic treatments led to a general increase in the dispersion properties, indeed a welcome development for its application in polymer blends.Financial support from the BIORENEW EU-project (NMP2-CT-2006-26456), Austrian Academic Exchange Programme (ÖEAD) and the Spanish projects BIO2007-28720-E, BIO2008-01533, and AGL2008-00709 is acknowledged.Peer reviewe
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