Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Int J Biol Macromol ; 267(Pt 2): 131364, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38583844

RESUMEN

3D printing technology demonstrates significant potential for the rapid fabrication of tailored geometric structures. Nevertheless, the prevalent use of fossil-derived compositions in printable inks within the realm of 3D printing results in considerable environmental pollution and ecological consequences. Lignin, the second most abundant biomass source on earth, possesses attributes such as cost-effectiveness, renewability, biodegradability, and non-toxicity. Enriched with active functional groups including hydroxyl, carbonyl, carboxyl, and methyl, coupled with its rigid aromatic ring structure and inherent anti-oxidative and thermoplastic properties, lignin emerges as a promising candidate for formulating printable inks. This comprehensive review presents the utilization of lignin, either in conjunction with functional materials or through the modification of lignin derivatives, as the primary constituent (≥50 wt%) for formulating printable inks across photo-curing-based (SLA/DLP) and extrusion-based (DIW/FDM) printing technologies. Furthermore, lignin as an additive with multi-faceted roles/functions in 3D printing inks is explored. The effects of lignin on the properties of printing inks and printed objects are evaluated. Finally, this review outlines future perspectives, emphasizing key obstacles and potential opportunities for facilitating the high-value utilization of lignin in the realm of 3D printing.


Asunto(s)
Tinta , Lignina , Impresión Tridimensional , Lignina/química
2.
Int J Biol Macromol ; 253(Pt 6): 126734, 2023 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-37683746

RESUMEN

Herein, a green facile approach to improve the flexibility of unbleached bamboo kraft pulp (UBKP) via an immobilized enzyme technology is proposed. Polydopamine (PDA) acts as versatile modification and coating materials of cellulose nanocrystals (CNC) for assembling versatile bio-carriers (PDA@CNC). Cellulase biomacromolecules are efficiently immobilized on PDA@CNC to form cellulase@PDA@CNC nanocomposites. The relative enzyme activity, temperature/pH tolerance, and storage stability of cellulase were significantly improved after immobilization. The degree of polymerization treated UBKP decreased by 5.42 % (25 U/g pulp) compared to the control sample. The flexibility of treated fibers was 6.61 × 1014/(N·m2), which was 96.93 % higher (25 U/g) compared to the control and 3.88 times higher than that of the blank fibers. Cellulase@PDA@CNC performs excellent accessibility to fiber structure and induces high degree of fibrillation and hydrolysis of UBKP fibers, which contributes high softness of obtained tissue handsheets. The bio-carrier PDA@CNC within paper framework may further enhance tissue tensile strength. This study proposes a practical and environmentally friendly immobilization approach of cellulase@PDA@CNC for improving the hydrolysis efficiency and flexibility of UBKP fibers, which provides the possibility to maintain the strength of tissue paper while improving its softness, thus broadening the high-value application of immobilized enzyme technology in tissue production.


Asunto(s)
Celulasa , Nanopartículas , Enzimas Inmovilizadas/química , Celulasa/química , Celulosa/química , Nanopartículas/química , Hidrólisis
3.
Carbohydr Polym ; 313: 120885, 2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37182973

RESUMEN

Tobacco based cellulose nanofiber (TCNF) is a novel nanocellulose that has recently been used to replace undesirable wood pulp fibers in the preparation of reconstructed tobacco sheets (RTS). However, given the strict requirements for controlling toxic chemical content in tobacco products, there is a global interest in developing a green, efficient, and toxic-chemical free approach to isolate TCNF from tobacco stem as a bioresource. In this study, we propose a creative and environmentally friendly method to efficiently and safely isolate TCNF from tobacco stem pulp, which involves integrated biological pretreatment followed by a facile mechanical defibrillation process. Feruloyl esterase is used to pretreat the stem pulp by disrupting the ether and ester bonds between lignin and polysaccharide carbohydrates within the fiber wall, which effectively facilitates cellulase hydrolysis and swelling of the stem pulp fiber, as well as the following mechanical shearing treatment for TCNF isolation. The results demonstrate that TCNF obtained by the comprehensive feruloyl esterase/cellulase/mechanical process exhibit uniform and well-dispersed nanofiber morphology, higher crystallinity, and stronger mechanical properties than those of the control. The addition of 0.5 % TCNF can replace wood pulp by 18 wt% ~ 25 wt% in the production of RTS samples while maintaining their reasonable strength properties.


Asunto(s)
Celulasa , Nanofibras , Celulosa/química , Nicotiana , Celulasa/química , Nanofibras/química , Hidrólisis
4.
Int J Biol Macromol ; 227: 608-618, 2023 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-36495988

RESUMEN

Lignin nanoparticles (LNPs), as one of green and sustainable biological macromolecules, have attracted great attention owing to their promising potentials in many valorized fields. However, the lignin heterogeneity seriously restricts the controllable preparation of LNPs. Herein, a facile nanogrinding activation combining anhydrous ethanol dissolution process was developed to efficiently homogenize lignin prior to gradient ethanol fractionation. Two lignin fractions were obtained from nanogrinding activation/ethanol dissolution followed by gradient ethanol fractionation: L-fractions and S-fractions. Therefore, monodispersed LNPs with unique concave hollow nanostructure and large particle size, and monodispersed LNPs with solid core nanostructure and small particle size were successfully prepared from L-fractions and S-fractions, respectively, via a GVL/water anti-solvent method. The proposed LNPs formation mechanisms facilitated by nanogrinding activation/ethanol dissolution treatment were demonstrated. This study put forwards a facile and green integrated approach for monodispersed LNPs preparation with controllable morphology and particle size.


Asunto(s)
Nanopartículas , Nanoestructuras , Etanol/química , Lignina/química , Nanopartículas/química , Solventes/química
5.
Cancer Manag Res ; 13: 7841-7850, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34703308

RESUMEN

INTRODUCTION: MiRNAs play a critical role in carcinogenesis, among which miR-10a-5p has been reported in several types of human cancer. Nevertheless, the role of miR-10a-5p remain uncovered in bladder cancer (BCa). METHODS: We recruited 88 BCa patients and 36 healthy controls (HC) to form the training cohort, and other 120 BCa patients to form the validation cohort. The clinical samples were collected for analysis. The expression level of miR-10a-5p was evaluated using RT-qPCR. Receiver operating characteristic (ROC) curves were utilized to calculate diagnostic accuracy. Survival curves were generated to analyze survival outcomes. CCK-8 and transwell assays were conducted to test the cell proliferation, migration, and invasion capacities. RESULTS: MiR-10a-5p was upregulated in human BCa tissues and closely associated with advanced clinicopathological features, including advanced tumor grade, histological grade, and T stage. High expression of miR-10a-5p was associated with worse survival outcomes in BCa patients. Circulating plasma miR-10a-5p expression had the great performance power to discriminate BCa patients form HC patients before surgery, and to differentiate muscle invasive bladder cancer (MIBC) from non-muscle invasive bladder cancer (NMIBC). In addition, overexpression of miR-10a-5p could promote BCa cell proliferation, migration, and invasion. CONCLUSION: This study indicates that miR-10a-5p is a crucial diagnostic and prognostic biomarker for BCa patients, and miR-10a-5p exerted a tumor promoting role during BCa cell progression.

6.
Carbohydr Polym ; 261: 117865, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33766353

RESUMEN

Nowadays, wood pulp addition (such as softwood, hardwood, etc.) into manufacture reconstructed tobacco sheet (RTS) via a paper-making process is a feasible and sustainable technology. However, the addition of wood pulp in RTS would weaken the tobacco fragrance of cigarette by bring wood gas when smoking. In this study, a practical and feasible pretreatment by hot water/cooking process combined with cationic modification/homogenization treatment was proposed to directly isolate desirable cellulose nanofibers from tobacco stem, named TCNF. The obtained TCNF was applied in the preparation of RTS to improve its physical properties but with a reduced wood pulp proportion (from 25 wt% decreased to 16 wt%). Results showed that TCNF exhibit a similar morphology with wood based nanocellulose, and that the addition of TCNF (0.5 wt% based dried tobacco pulp) can substitute 9 % of wood pulp compared with that of the control at the similar physical properties.

7.
Carbohydr Polym ; 251: 117107, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33142644

RESUMEN

Biobased N-doped hierarchically porous carbon (N-HPC) electrodes were successfully prepared by utilizing marine crustacean derivatives and chitin nanofibers (ChNF), as versatile bio-templates of zeolitic imidazolate frameworks (ZIF-8) to form ChNF@ZIF-8 nanocomposites, followed by a subsequent carbonization process. The ZIF-8 nanoparticles were in situ synthesized on ChNF surfaces to avoid fragmentation for fabricating hierarchically porous carbon structure (N-HPC), which is efficiently doped with rich nitrogen content that originates in ChNF and ZIF-8. The results show that N-HPC electrodes demonstrate improved electrochemical performance and the constructed symmetric supercapacitor assembled with N-HPC exhibits enhanced capacitive performance of specific capacity (128.5 F·g-1 at 0.2 A·g-1) and excellent electrochemical stability even after 5000 cycles. This facile and effective preparation method of N-HPC electrodes derived from marine crustacean nanomaterials will have great potential in the construction of next-generation electrochemical energy-storage devices with excellent capacitance performance.


Asunto(s)
Carbono/química , Quitina/química , Imidazoles/química , Nanofibras/química , Nanoestructuras/química , Zeolitas/química , Capacidad Eléctrica , Electrodos , Porosidad
8.
Carbohydr Polym ; 250: 116881, 2020 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-33049824

RESUMEN

Three-dimensional (3D) printing, known as revolutionary and disruptive innovation in manufacturing technology, supports great opportunities to rapidly construct a wide range of tailored object geometries. Cellulose, hemicellulose, and lignin as the three most common natural polymers and main components of plant resources, possess great economical potential for bio-based products due to their attractive advantages. The integration of 3D printing technology involved with cellulose, hemicellulose and lignin as the major bio-based feedstock for high-performance 3D printed products has received great concern in the R&D areas. In this review, the aim is to shed light on a cutting-edge review on the most recent progress based on cellulose, hemicellulose and lignin, as well as their derivatives as multi-components of bio-feedstock for 3D printing, in which the applications, roles and functions of the plant-derived biomass for 3D printing are also highlighted. The challenges and perspectives for future work are provided, to underscore critical issues and opportunities.


Asunto(s)
Biomasa , Biotecnología/métodos , Celulosa/química , Lignina/química , Plantas/química , Polisacáridos/química , Impresión Tridimensional/instrumentación
9.
Carbohydr Polym ; 242: 116384, 2020 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-32564822

RESUMEN

Starch based bio-latex has been widely researched in the coating paper area for the purpose of partial replacement of petroleum-based binders. In this paper, a green and facile ball milling pretreatment was proposed to modify the starch granules before α-amylase hydrolysis by breaking up their crystalline structure, thus improving the accessibility and susceptibility of amylase into starch structure. It was found that the improved hydrolysis process after 8 h ball milling can generate suitable degree of polymerization of polysaccharides or oligosaccharides, which further facilitated the following H2O2 oxidation and SHMP crosslinking processes. In addition, a mechanism was also demonstrated to illustrate the improvement induced by ball milling pretreatment. The prepared bio-latex with crosslinking-structure performed excellent adhesive properties when substituted 25 % of petroleum-based latex during paper coating application, which showed great potential in improving the economic, cost, and environment benefits of traditional production of coated paper.


Asunto(s)
Látex/biosíntesis , Almidón/metabolismo , alfa-Amilasas/metabolismo , Peróxido de Hidrógeno/química , Peróxido de Hidrógeno/metabolismo , Hidrólisis , Látex/química , Oxidación-Reducción , Tamaño de la Partícula , Almidón/química , Propiedades de Superficie , alfa-Amilasas/química
10.
Carbohydr Polym ; 234: 115942, 2020 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-32070552

RESUMEN

The target of the study is to improve the yield and the colloidal stability of cellulose nano-crystals (CNC) that is obtained through maleic acid hydrolysis. Herein, a facile/ green approach to prepare CNC with high yield and colloidal stability from bamboo fibers is presented. Ball mill pretreatment can break down and open up the structure of bamboo fibers, thus exposing more hydroxyl groups on the surface of pulp fibers and increasing the access of acid molecules into pulp fibers. The maleic acid molecules can easily hydrolyze cellulose, thus releasing more crystalline parts; maleic acid anhydride can react with hydroxyl groups to generate more -COOH groups on CNC. The yield of resultant CNC was 10.55-24.50 %, which was much higher than 2.80 % of the control. The study put forward a facile approach to prepare CNC with high yield and colloidal stability, and paves a possible way for industrialization of CNC production.

11.
Carbohydr Polym ; 229: 115434, 2020 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-31826497

RESUMEN

In recent years, cellulose nano-fibers (CNF) have been regarded as renewable, promising reinforcer to enhance the strength property of paper products. In this paper, the roles of cationic cellulose nano-fibers (CCNF) as versatile flocculants of wood pulp and fines in pulp slurry for high wet web performance have been studied. It was found that CCNF can induce significantly flocculation (CCNF-Fines complex) in pulp slurries. The mechanical properties of wet web can also be improved by the addition of CCNF. The study demonstrated that CCNF can act as effective flocculants of fines and form CCNF-Fines complex for improved wet-web strength, in addition, CCNF has little effect on the dewatering rate of wet-web. CCNF is more beneficial to the wet web performance when it is in higher charge density. The research paves a way to further study the comprehensive application of CCNF in the wet-web making process for high performance.

12.
Carbohydr Polym ; 210: 332-338, 2019 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-30732769

RESUMEN

The properties of wet-web strength and pressability of base paper affect the frequency of sheet breaks and machine runnability during the paper-making process. In this paper, the effect of nano-fibrillated cellulose (NFC) on the wet-web strength and pressability of paper sheet during the press process of paper-making was explored. It was found that the tensile energy absorption (TEA) of the sample was increased from 6.32 to 10.93 J/m2 at 50% wet web solid content when 5% NFC was added. The web solid content was decreased from 50.51% to 42.85% when 0%-5% NFC was added under the same drainage and press conditions, indicating that the addition of NFC during the paper-making process can retard the pressability of paper sheet. The study put forwards a new view to discuss/study the effect of added NFC on the wet-web strength and pressability of paper sheet.

13.
Opt Express ; 26(15): 19470-19478, 2018 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-30114118

RESUMEN

We present the potential of an antireflection self-reference method based on ultra-thin tantalum nitride (TaN) nanofilms for improving terahertz (THz) reflection spectroscopy. The antireflection self-reference method is proposed to eliminate mutual interference caused by unwanted reflections, which significantly interferes with the important reflection from the actual sample in THz reflection measurement. The antireflection self-reference model was investigated using a wave-impedance matching approach, and the theoretical model was verified in experimental studies. We experimentally demonstrated this antireflection self-reference method can completely eliminate the effect of mutual interference, accurately recover the actual sample's reflection and improve THz reflection spectroscopy. Our method paves the way to implement a straightforward, accurate and efficient approach to investigate THz properties of the liquids and biological samples.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...