RESUMO
Accidental diesel spills can occur in marine environments such as harbors, leading to adverse effects on the environmental compartment and humans. This study proposes the surgical mask as an affordable and sustainable adsorbent for the remediation of diesel-contaminated seawater to cope with the polymeric waste generated monthly in hospital facilities. This approach can also be helpful considering a possible future pandemic, alleviating the pressure on the waste management system by avoiding improper mask incineration and landfilling, as instead occurred during the previous COVID-19. Batch adsorption-desorption experiments revealed a complete diesel removal from seawater after 120 min with the intact laceless mask, which showed an adsorption capacity of up to 3.43 g/g. The adsorption curve was better predicted via Weber and Morris's kinetic (R2 = 0.876) and, in general, with Temkin isotherm (R2 = 0.965-0.996) probably due to the occurrence of chemisorption with intraparticle diffusion as one of the rates-determining steps. A hysteresis index of 0.23-0.36 was obtained from the desorption isotherms, suggesting that diesel adsorption onto surgical masks was faster than the desorption mechanism. Also, the effect of pH, ionic strength and temperature on diesel adsorption was examined. The results from the reusability tests indicated that the surgical mask can be regenerated for 5 consecutive cycles while decreasing the adsorption capacity by only approximately 11%.
Assuntos
Gerenciamento de Resíduos , Poluentes Químicos da Água , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Polímeros , Água do Mar , Termodinâmica , Poluentes Químicos da Água/análiseRESUMO
This study proposes new perspectives for the management and biorefinery of wastes deriving from the agri-food sector such as chestnut shell (CS), which was here used as an organic feedstock for biomethane production through anaerobic digestion (AD). 1-5% alkaline (i.e. NaOH and KOH), hydrothermal (i.e. at 100 °C) and combined hydrothermal-alkaline pretreatments were employed to enhance the CS biodegradability prior to biochemical methane potential (BMP) tests conducted under mesophilic conditions. The hydrothermally-pretreated CS with 3% NaOH achieved the highest biomethane yield of 253 (±9) mL CH4·g VS-1 coupled to a volatile solid reduction of 48%. The hydrothermal-alkaline pretreatment positively affected both delignification and hemicellulose polymerization, promoting an approximately 2.4-fold higher substrate biodegradability compared to the untreated CS, which only reached a CH4 production of 104 (±5) mL CH4·g VS-1. AD proceeded via volatile fatty acid accumulation, subsequently followed by methane production that was effectively simulated via the modified Gompertz kinetic having a R2 of 0.974-0.999. Among the physical-chemical parameters characterizing the CS, the soluble chemical oxygen demand (sCOD) was highly correlated with the BMP showing a Pearson coefficient of 0.952. The cumulative biomethane yield, the sCOD and the cellulose, hemicellulose and lignin amount of CS were also processed through the least square method, obtaining a useful regression equation to predict the BMP. The economic assessment indicated that the hydrothermal-alkaline pretreatment is a cost-effective method to improve the BMP of CS, also for future full-scale applications.
Assuntos
Lignina , Metano , Anaerobiose , Celulose , Lignina/metabolismoRESUMO
PURPOSE: To investigate dynamic contrast enhanced-MRI (DCE-MRI) in the preoperative chemo-radiotherapy (CRT) assessment for locally advanced rectal cancer (LARC) compared to18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT). METHODS: 75 consecutive patients with LARC were enrolled in a prospective study. DCE-MRI analysis was performed measuring SIS: linear combination of percentage change (Δ) of maximum signal difference (MSD) and wash-out slope (WOS). 18F-FDG PET/CT analysis was performed using SUV maximum (SUVmax). Tumor regression grade (TRG) were estimated after surgery. Non-parametric tests, receiver operating characteristic were evaluated. RESULTS: 55 patients (TRG1-2) were classified as responders while 20 subjects as non responders. ΔSIS reached sensitivity of 93%, specificity of 80% and accuracy of 89% (cut-off 6%) to differentiate responders by non responders, sensitivity of 93%, specificity of 69% and accuracy of 79% (cut-off 30%) to identify pathological complete response (pCR). Therapy assessment via ΔSUVmax reached sensitivity of 67%, specificity of 75% and accuracy of 70% (cut-off 60%) to differentiate responders by non responders and sensitivity of 80%, specificity of 31% and accuracy of 51% (cut-off 44%) to identify pCR. CONCLUSIONS: CRT response assessment by DCE-MRI analysis shows a higher predictive ability than 18F-FDG PET/CT in LARC patients allowing to better discriminate significant and pCR.
Assuntos
Quimiorradioterapia Adjuvante , Imageamento por Ressonância Magnética , Terapia Neoadjuvante , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias Retais/diagnóstico por imagem , Neoplasias Retais/terapia , Adulto , Idoso , Área Sob a Curva , Meios de Contraste/administração & dosagem , Procedimentos Cirúrgicos do Sistema Digestório , Feminino , Fluordesoxiglucose F18/administração & dosagem , Humanos , Nanopartículas de Magnetita/administração & dosagem , Masculino , Pessoa de Meia-Idade , Imagem de Perfusão/métodos , Valor Preditivo dos Testes , Curva ROC , Compostos Radiofarmacêuticos/administração & dosagem , Neoplasias Retais/irrigação sanguínea , Neoplasias Retais/patologia , Fluxo Sanguíneo Regional , Indução de Remissão , Reprodutibilidade dos Testes , Siloxanas/administração & dosagem , Resultado do TratamentoRESUMO
BACKGROUND: Enzyme replacement treatment with recombinant human alpha-galactosidase A (r-halphaGalA) is now available for patients with Fabry disease, many of whom are on maintenance hemodialysis. Because r-halphaGalA must be infused over several hours, administering the enzyme during dialysis would save a day of treatment for patients receiving both therapies. However, these procedures have never been combined due to concerns about possible loss of enzyme in the dialysate. METHODS: Ten Fabry patients received r-halphaGalA (1 mg/kg body weight continuously infused over 4 hours) during dialysis and separately in the interval between dialysis treatments. Plasma activity of r-halphaGalA was measured at baseline and then every hour for both procedures. In two patients, a third r-halphaGalA infusion during dialysis with a high-flux membrane was followed. RESULTS: The rise in plasma concentrations of r-halphaGalA during infusion and the steady-state levels reached were comparable for enzyme administrations with or without dialysis. The trend for the somewhat higher activities during hemodialysis was explained by volume contraction due to ultrafiltration. With the use of a high-flux dialyzer, the plasma r-halphaGalA activities were identical to those that were observed during low-flux dialysis. CONCLUSIONS: Administration of r-halphaGalA during hemodialysis is not associated with a reduced activity of r-halphaGalA therapy in patients with Fabry disease. Replacement therapy with r-halphaGalA may therefore be performed during hemodialysis without apparent loss of enzyme into the dialysate.