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1.
Int J Biol Macromol ; 269(Pt 1): 131881, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38677705

RESUMO

This work focuses on the precipitation of lignin from kraft black liquor (BL) along with its valorization into lignin nanoparticles (LNP). Two organic acids namely, acetic acid, and lactic acid were used for the precipitation of lignin as an alternative to sulfuric acid. An optimization study was carried out to determine the effect of three key variables, namely acid type, temperature, and pH, on the isolation yield and purity of lignin. The study showed that all factors primarily influenced the lignin yield, while the purity of precipitated lignin varied only around 1 % between minimum to maximum purity. Further, the acid precipitation method was selected for the preparation of LNP. The study aimed to observe the effect of pH, lignin concentration, and surfactant concentration over the properties of the prepared nanoparticles. The results showed that a smaller nanoparticle size and maximization of phenolic content was achieved with a lignin concentration of 35 mg/mL, a surfactant concentration of 10 % (w/w lignin), and a pH of 5. Additionally, the antibacterial activity of LNPs against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa bacteria was evaluated. The results showed only minor activity against Staphylococcus aureus. Overall, the study demonstrates the potential method for precipitation and valorization of lignin through the production of LNP with desirable properties.

2.
ACS Omega ; 9(4): 4762-4774, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38313486

RESUMO

This study explores the integration of zinc oxide coated with polyaniline (ZnO-PANI) nanoparticles into a poly(ether sulfone) (PES) matrix to concurrently enhance permeate flux and oleuropein (OLP) rejection during the filtration of olive leaf extract (OLE). The effect of ZnO-PANI content on porosity, pore size, surface hydrophilicity, and pure water flux (PWF) was studied. The results indicate that an increase in ZnO-PANI content (0-0.2%) leads to a 3-fold increase in mean pore size, permeability (1.29-7.18 L/m2 h bar), porosity (72.2-77.8%), and improved surface hydrophilicity of the prepared membranes. Membrane performance was tested for OLE permeate flux of the OLE and total phenolic compounds (TPC) rejection at various pressures (10-30 bar), the performance of the OLP rejection at 30 bar, and fouling resistance. The 0.2 wt % ZnO-PANI membrane exhibits the highest permeate flux, while the 0.4 wt % ZnO-PANI membrane offers the highest rejection values (90-97% for TPC and 100% for OLP). Bare PES demonstrated the best fouling resistance. Strategic ZnO-PANI incorporation achieves a balance, enhancing both the flux and rejection efficiency. The 0.2 wt % ZnO-PANI membrane emerges as particularly favorable, striking a beneficial equilibrium between permeate flux and OLP rejection. Intriguingly, the use of these membranes for OLE filtration, postpretreatment with ultrafiltration (UF), results in a remarkable 100% rejection of OLP. This discovery underscores the significant and specific separation of OLP from OLE facilitated by a ZnO-PANI-based mixed matrix membrane (MMM). The study contributes valuable insights into the development of advanced membranes with enhanced filtration capabilities for high-added value phenolic compound separation.

3.
Membranes (Basel) ; 13(2)2023 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-36837740

RESUMO

Lignin is a polyphenolic biopolymer present in large amounts in black liquor (BL). This work investigated the recovery of lignin from BL (pre-filtered by ultrafiltration (UF)) by nanofiltration (NF). For the NF tests, laboratory-made mixed matrix membrane (MMM) prepared with 0.1% activated carbon (AC) nanoparticles were used in crossflow filtration mode. The effect of pressure (6-15 bar) and volume reduction (VR) (~65%) were analyzed, and the filtration performance was evaluated in terms of permeate flux, lignin rejection rate, and flux reduction. The lignin rejection rate varied in the range of 67-80% with the pressure, however, the highest increases in flux and rejection were observed at 12 bar, which was found to be the optimum pressure. At a VR of ~65%, the permeate flux decreased by ~55% and the lignin rejection rate increased from 78% to 86%. In addition, an economic evaluation was performed for the preparation of UF and NF MMM. The minimum-to-maximum price range was estimated considering the costs of the laboratory and commercial grade regents. It showed a difference of ~10-fold and ~14-fold for UF and NF membranes, respectively. The results of the laboratory-scale study were used to evaluate the economic feasibility of the process for recovering lignin- and hemicellulose-rich retentate streams.

4.
Rep Pract Oncol Radiother ; 26(4): 503-511, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34434565

RESUMO

BACKGROUND: To report clinical outcomes and late toxicities of a 2-week hypofractionated post-operative loco-regional radiotherapy in patients with breast cancer. MATERIALS AND METHODS: This trial was approved by the Institutional Ethics Committee and registered with gov, no. NCT02460744. Between June 2013 and October 2014, 50 patients with breast cancer, post mastectomy or breast conserving surgery (BCS) were included in this study, of whom 10 had BCS. Patients were planned on a 2-dimentional (2D) simulator with 2 tangential fields and an incident supraclavicular field. Radiotherapy dose was 34 Gy/10#/2 weeks and a sequential boost of 10 Gy/5#/1 wk in BCS patients. The primary endpoint was the rate of acute skin toxicities previously reported. Here, we report the secondary end points of late toxicities, cosmesis, local recurrence, disease-free survival (DFS) and overall survival (OS). Late skin toxicities were recorded according to the Radiotherapy and Oncology Group (RTOG) scoring criteria. Cosmetic outcomes were assessed using the Harvard/National Surgical Adjuvant Breast and Bowel Project (NSABP)/RTOG breast cosmesis and the Late Effects Normal Tissue/Subjective Objective Management Analytic (LENT/SOMA) scales for the breast and chest wall, respectively. Kaplan-Meier estimates of DFS and OS were calculated, and 5-year DFS and OS rates (with approximate 95% CIs) were estimated. RESULTS: Late grade ≥ 2 chest wall induration, hypopigmentation and subcutaneous fibrosis were seen in 3 (6%), 3 (6%) and 1 (2%) patients, respectively. Chest wall cosmesis was excellent/good in 34 (72%) and fair/bad in 13 (28%) patients. In BCS patients, grade 2 skin induration, subcutaneous fibrosis and edema was observed in 1 patient (11%) each. Cosmesis was excellent/good in 7 (78%) and fair/bad in 2 (22%) patients. Late grade ≥ 2 arm edema, pain and shoulder stiffness were reported by 1 (2%), 2 (4%) and 2 (4%) patients, respectively. No local recurrences were observed. Five patients developed distant metastases (10%). Seven patients died (14%). The 5-year DFS and OS rate was 90% (95% CI: 77-96%) and 88% (95% CI: 75-94%), respectively. CONCLUSION: Hypofractionated radiotherapy in 2 weeks in patients with breast cancer was associated with minimal late toxicity, good cosmetic outcome and excellent local control. This trial may be of relevance for developing countries where resources are limited.

5.
Protoplasma ; 253(3): 709-718, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26615604

RESUMO

The present study demonstrates the comparative response of two contrasting genotypes (aluminum (Al) tolerant and Al sensitive) of chick pea (Cicer arietinum) against Al stress. The Al-tolerant genotype (RSG 974) showed lesser inhibition of root growth as well as lower oxidative damages, measured in terms of the accumulation of H2O2 and lipid peroxidation compared to the Al-sensitive genotype (RSG 945). The accumulation of Al by roots of both genotypes was almost equal at 96 and 144 h after Al treatment; however, it was higher in Al-tolerant than Al-sensitive genotype at 48 h after Al treatment. Further, the Al-mediated induction of superoxide dismutase (SOD) activity was significantly higher in Al-tolerant than Al-sensitive genotype. Ascorbate peroxidase (APX) activity was almost similar in both genotypes. Al treatment promptly activated catalase activity in Al-tolerant genotype, and it was remarkably higher than that of Al-sensitive genotype. As another important Al detoxification mechanism, citrate efflux was almost equal in both genotypes except at 1000 µM Al treatment for 96 and 144 h. Further, citrate carrier and anion channel inhibitor experiment confirmed the contribution of citrate efflux in conferring Al tolerance in Al-tolerant genotype. Based on the available data, the present study concludes that rapid activation of catalase (also SOD) activity followed by citrate efflux effectively improves Al tolerance in chick pea.


Assuntos
Alumínio/toxicidade , Catalase/metabolismo , Cicer/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Alumínio/farmacocinética , Ascorbato Peroxidases/metabolismo , Cicer/genética , Cicer/fisiologia , Ácido Cítrico/metabolismo , Ativação Enzimática/efeitos dos fármacos , Genótipo , Peróxido de Hidrogênio/metabolismo , Inativação Metabólica , Peroxidação de Lipídeos/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Raízes de Plantas/genética , Superóxido Dismutase/metabolismo
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