Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Br J Pharmacol ; 2024 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-38715438

RESUMEN

BACKGROUND AND PURPOSE: Chemotherapy-induced peripheral neuropathy (CIPN) commonly causes neuropathic pain, but its pathogenesis remains unclear, and effective therapies are lacking. Naringenin, a natural dihydroflavonoid compound, has anti-inflammatory, anti-nociceptive and anti-tumour activities. However, the effects of naringenin on chemotherapy-induced pain and chemotherapy effectiveness remain unexplored. EXPERIMENTAL APPROACH: Female and male mouse models of chemotherapy-induced pain were established using paclitaxel. Effects of naringenin were assessed on pain induced by paclitaxel or calcitonin gene-related peptide (CGRP) and on CGRP expression in dorsal root ganglia (DRG) and spinal cord tissue. Additionally, we examined peripheral macrophage infiltration, glial activation, c-fos expression, DRG neuron excitability, microglial M1/M2 polarization, and phosphorylation of spinal NF-κB. Furthermore, we investigated the synergic effect and related mechanisms of naringenin and paclitaxel on cell survival of cancer cells in vitro. KEY RESULTS: Systemic administration of naringenin attenuated paclitaxel-induced pain in both sexes. Naringenin reduced paclitaxel-enhanced CGRP expression in DRGs and the spinal cord, and alleviated CGRP-induced pain in naïve mice of both sexes. Naringenin mitigated macrophage infiltration and reversed paclitaxel-elevated c-fos expression and DRG neuron excitability. Naringenin decreased spinal glial activation and NF-κB phosphorylation in both sexes but influenced microglial M1/M2 polarization only in females. Co-administration of naringenin with paclitaxel enhanced paclitaxel's anti-tumour effect, impeded by an apoptosis inhibitor. CONCLUSION AND IMPLICATIONS: Naringenin's anti-nociceptive mechanism involves CGRP signalling and neuroimmunoregulation. Furthermore, naringenin facilitates paclitaxel's anti-tumour action, possibly involving apoptosis. This study demonstrates naringenin's potential as a supplementary treatment in cancer therapy by mitigating side effects and potentiating efficacy of chemotherapy.

3.
Environ Pollut ; 337: 122519, 2023 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-37690466

RESUMEN

Although alternatives to mercury (Hg) are available in most products and industrial activities, Hg continues to be an ingredient in some products, including fluorescent lamps and electrical and electronic equipment (EEE). In this work, low-cost passive air samplers (PASs) were used to investigate the atmospheric Hg pollution in Zhongshan, a large industrial city and major hub of mercury-added product manufacturing in South China. The GEM concentrations in the atmosphere were measured for two weeks during the summer of 2019 at a total of 144 sites across Zhongshan. Comparison with the results of active sampling confirmed that the PASs yielded accurate and reliable gaseous elemental mercury (GEM) concentrations and were thus well-suited for multi-site field monitoring. The mean GEM concentrations in the areas with mercury-added product manufacturing activities (5.1 ± 0.4 ng m-3) were significantly higher than those in other parts of Zhongshan (1.5 ± 0.4 ng m-3), indicating that local releases, rather than regional transport, were responsible for the atmospheric Hg pollution. Elevated GEM concentrations (up to 11.4 ng m-3) were found in the vicinity of fluorescent lamp and EEE factories and workshops, indicating significant Hg vapor emissions, presumably from the outdated production technologies and non-standard operation by under-trained workers. The Hg emissions from mercury-added product manufacturing were estimated to be 0.06 and 7.8 t yr-1 for Zhongshan and China, respectively, based on the scales of fluorescent lamp and EEE production. The non-carcinogenic health risk of Zhongshan residents from inhalation and ingestion was judged acceptable, whereby the inhalation exposure in Hg-polluted areas exceeded that of dietary ingestion. These findings demonstrate that mercury-added product manufacturing still contributes notably to anthropogenic gaseous Hg releases in the industrial areas with intense mercury-added product manufacturing activities.


Asunto(s)
Contaminantes Atmosféricos , Mercurio , Humanos , Mercurio/análisis , Monitoreo del Ambiente/métodos , Contaminantes Atmosféricos/análisis , Aire , Atmósfera , Gases
4.
Int J Biol Macromol ; 253(Pt 1): 126486, 2023 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-37633559

RESUMEN

Anti-ultraviolet material with cost-effectiveness, environmental friendliness, and multifunction is urgently needed to address the serious problem of ultraviolet radiation. However, traditional anti-ultraviolet products based on plastics are unsustainable and harmful to the environment. Herein, the cellulose films with a sandwich structure using a surface assembly technique were reported. Natural L-phenylalanine was grafted onto cellulose nanofibrils via amidation to enhance their UV-shielding property. To address the hydrophilic nature and limited mechanical strength of cellulose films, we employed octadecyltrichlorosilane and 4ARM-PEG-NH2 for hydrophobic coating and mechanical reinforcement, respectively. In addition to providing complete UV resistance in the wavelength range of 200-320 nm, sample OPT5 exhibited significantly improved tensile stress, Young's modulus, and toughness, measuring 174.09 MPa, 71.11 MPa, and 295.33 MJ/m3, respectively. Furthermore, due to the presence of antibacterial amine groups, the modified film demonstrated a satisfactory inhibitory effect on the growth of Escherichia coli and Bacillus subtilis. Compared to natural cellulose films, the hydrophobically modified material achieved a contact angle of up to 121.1°, which enabled efficient separation of oil-water mixtures with a maximum separation efficiency of 93.87 %. In summary, the proposed TOCNF-based UV-shielding film with multifunctionality holds great potential for replacing petrochemical-derived plastics and serving as an applicable and sustainable membrane material.


Asunto(s)
Celulosa Oxidada , Rayos Ultravioleta , Nanopartículas Capa por Capa , Celulosa/química , Agua
5.
ACS Appl Mater Interfaces ; 15(27): 32538-32551, 2023 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-37358083

RESUMEN

Cs2SnI6 powder is, for the first time, solution-prepared via the formula CsI + SnI2 + I2 → Cs2SnI6. The product is highly pure and air/thermal stable. It is found that N,N-dimethylformamide (DMF) and methanol induce severe Cs2SnI6 deterioration with the appearance of a CsI phase in film preparation from Cs2SnI6 powder, while solvents of γ-butyrolactone (GBL) and ethylene glycol methyl ether (EGME) (Film-EGME) give better results. Then, by introducing EGME solvent, in situ preparation of Cs2SnI6 films (Film-1 to Film-4) is realized under solution reaction, which is found to be dominated by thermal dynamic process, i.e., highly pure/oriented Film-4 is obtained under the maximum reagent-concentration. Besides, for good reaction, the solubility of solvent should be balanced among all the reagents and products. Solid-state dye sensitized solar cells (ss-DSSCs) comprising a Cs2SnI6 electrolyte are investigated. The power conversion efficiencies (PCEs) of the ss-DSSCs based on solution-casted Film-EGME and the in situ-prepared Film-4 are 1.81% and 3.30%, respectively. Particularly, with the in situ prepared Cs2SnI6 films, it is found that the open circuit voltages of the ss-DSSCs are closely related to their gap states. When additive is added in Cs2SnI6 electrolyte, a PCE of 6.14% is obtained in an ss-DSSC. Our work highlights the importance of solvent in film preparation and the role of Cs2SnI6 gap states in device performance.

6.
Commun Biol ; 6(1): 155, 2023 02 07.
Artículo en Inglés | MEDLINE | ID: mdl-36750663

RESUMEN

The dynamic assembly of the Synaptic-soluble N-ethylmaleimide-sensitive factor Attachment REceptor (SNARE) complex is crucial to understand membrane fusion. Traditional ensemble study meets the challenge to dissect the dynamic assembly of the protein complex. Here, we apply minute force on a tethered protein complex through dual-trap optical tweezers and study the folding dynamics of SNARE complex under mechanical force regulated by complexin-1 (CpxI). We reconstruct the clamp and facilitate functions of CpxI in vitro and identify different interplay mechanism of CpxI fragment binding on the SNARE complex. Specially, while the N-terminal domain (NTD) plays a dominant role of the facilitate function, CTD is mainly related to clamping. And the mixture of 1-83aa and CTD of CpxI can efficiently reconstitute the inhibitory signal identical to that the full-length CpxI functions. Our observation identifies the important chaperone role of the CpxI molecule in the dynamic assembly of SNARE complex under mechanical tension, and elucidates the specific function of each fragment of CpxI molecules in the chaperone process.


Asunto(s)
Pinzas Ópticas , Proteínas SNARE , Proteínas SNARE/química , Proteínas SNARE/metabolismo , Fusión de Membrana
7.
Opt Express ; 31(2): 2523-2537, 2023 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-36785264

RESUMEN

Ultrathin broadband absorber maintaining a near-uniform low reflectivity over a broadband wavelength is essential for many optical applications, such as light harvesting and nanoscale imaging. Recently, there has been considerable interest in employing arrays of high-index dielectric Mie resonators on surfaces to trap light and reduce the reflectivity. For such Mie-resonant metasurfaces, however, antireflection properties featuring both a flat low reflectance curve and a wide bandwidth are hard to be satisfied simultaneously, and an efficient large-scale nanofabrication technique rarely exists. Here, we present a high-throughput laser interference induced quasi-random patterning (LIIQP) technique to fabricate quasi-random Mie resonators in large scale. Mie resonators with feature sizes down to sub-100 nm have been fabricated using a 1064 nm laser source. Each Mie resonator concentrates light at its shape-dependent resonant frequency, and all such resonators are arranged quasi-randomly to provide both rich (with broadband Fourier components) and strong (with large intensities) Fourier spectra. Specifically, a near-uniform broadband reflectivity over 400-1100 nm spectrum region has been confined below 3% by fabricating a large-scale ultrathin (around 400 nm) absorber. Our concept and high-throughput fabrication technique allows the rapid production of quasi-random dielectric Mie-resonant metasurfaces in a controllable way, which can be used in various promising applications including thin-film solar cells, display, and imaging.

8.
Int J Biol Macromol ; 233: 123451, 2023 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-36709821

RESUMEN

Nowadays, organic pollutants have been major concerns in many fields. Production of functional materials based on renewable and sustainable resources for organic pollutants detection and removal was of much interest. Herein, multi-functional nanocomposite films based on cellulose nanocrystals (CNCs) with high optical haze, organic pollutant detection and emulsion separation capabilities, have been successfully fabricated based on hydrophobically-modified CNCs suspensions by 2-dodecen-1-succinic anhydride (DDSA) followed by radical polymerization with tridecafluorooctyl (TFMA). The suspensions displayed satisfying oil-in-water emulsion stabilization capabilities and the vacuum-dried films showed birefringence, high transparency, and optical haze (~85 %), due to the ordered arrangements of cellulose nanocrystals. The organic pollutant can be detected through the iridescent colors disappearing by Polarizing Optical Microscope observation. In addition of improved mechanical strength for application (27 MPa) and high contact angle of 131.6°, the hydrophobic films performed as high separation efficiency as >90 % of emulsion, due to the successfully grafting of hydrophobic molecules on the surface of CNCs. Thus, the surface modification for CNCs provide a facile approach of emulsification, pollutants detection and separation properties, which would widen the application potentials of renewable cellulosic resources in fields of environmental protection, engineering control and petroleum industry.


Asunto(s)
Nanocompuestos , Nanopartículas , Emulsiones , Suspensiones , Nanopartículas/química , Nanocompuestos/química , Celulosa/química
9.
Int J Biol Macromol ; 223(Pt A): 49-56, 2022 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-36349657

RESUMEN

The exploration of sustainable lignocellulosic nanomaterials with unique properties and applicable functions is receiving growing interest. In this work, holocellulose nanofibrils (HCNFs) were prepared from moso bamboo using mild alkaline peroxide bleaching method (MAPB) followed by mechanical nanofibrillation. MAPB was proved to effectively remove lignin and retain hemicellulose. Meanwhile, partial allomorphic changes from cellulose I to cellulose II were revealed together with varying degrees of crystallinity. Thermogravimetric analysis (TGA) experiment showed an increasing thermal stability trend due to more allomorphic changes into anti-parallel cellulose II. Well-dispersed HCNFs suspensions were successfully prepared by homogenization and HCNFs films with high transparency and flexibility were fabricated. The films reached the maximum tensile strength of 55.8 MPa and tensile strain of 1.55 % along with a calculated toughness of 25 MJ/m3. Moreover, the prepared materials are biocompatible and completely non-toxic, which will theoretically support the application of HCNFs materials in fields of biology, medicine and food industry.


Asunto(s)
Celulosa , Nanoestructuras , Peróxidos , Lignina , Resistencia a la Tracción
10.
Opt Express ; 30(12): 21931-21942, 2022 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-36224903

RESUMEN

Optical solitons, particle-like excitations ubiquitous in many fields, can bind to form soliton molecules with striking molecule-like interactions. However, the exotic soliton interactions in soliton molecules are still largely unexplored in dual-wavelength mode-locked fiber lasers. Here, we reveal the dynamics of dissipative soliton molecules with periodic solitons collision in a dual-wavelength ultrafast fiber laser. The soliton molecules with a central wavelength of 1532.8 nm and 1561 nm exhibit conspicuously different evolution characteristics attributed to the difference in gain spectral intensity and trapped potential. The long-wavelength soliton molecule swiftly recovers to the initial state after collision, while the short-wavelength soliton molecule has a remarkable variation in temporal separation and operation state. Moreover, the multiple intensive repulsion and attraction in soliton molecule with energy transfer between leading and trailing solitons, and the formation of triplet soliton molecule in short-wavelength with multiple switching have also been observed. The different oscillating solutions coexisting in dual-wavelength soliton molecules involving oscillating and sliding phase evolution confirm the multistability of the dissipative system. These findings shed new insights into the dynamics of soliton molecules and solitons collision in nonlinear systems.

11.
Int J Biol Macromol ; 223(Pt B): 1633-1640, 2022 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-36270399

RESUMEN

Light pollution from ultraviolet (UV) radiation is gaining growing concerns, as the emissions and burning of fossil fuels destroyed the ozone layer. Seeking a solution against skin exposure to excessive radiation is an urgent requirement. In this study, nicotinamide (NA), the main component of vitamin B3, was introduced as a new modifier into Tempo-oxidized cellulose nanofibrils (TOCNFs) together with the physical cross-linking with tannin acid (TA) to improve anti-UV performance of the nanocomposite films. Incorporation of NA into the films presents distinguished UV shielding capability UVB wavelength range from 200 nm to 320 nm (NTA1-5) due to the introduced functional groups like CO and benzene rings. Moreover, mechanical properties were notably enhanced, which overcome the low strength of common nanocellulosic materials. The stress increased from 69.8 MPa to 116.3 MPa, and the toughness can reach 131.58 MJ/m3 by tuning the additional amount of NA. Meanwhile, TGA and DTG analysis demonstrated that the incorporation of amide bonds and TA into the composite films greatly improved the thermal stability. Thus, the proposed materials fabricated from natural biomolecules show great potential in serving as new kinds of UV-resistant products in the application areas of sunscreen, protective clothing, and building materials.


Asunto(s)
Celulosa Oxidada , Nanocompuestos , Celulosa Oxidada/química , Celulosa/química , Niacinamida , Nanocompuestos/química , Protectores Solares
12.
Opt Lett ; 47(11): 2710-2713, 2022 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-35648911

RESUMEN

We demonstrate second-harmonic generation (SHG) microscopy excited by the ∼890-nm light frequency-doubled from a 137-fs, 19.4-MHz, and 300-mW all-fiber mode-locked laser centered at 1780 nm. The mode-locking at the 1.7-µm window is realized by controlling the emission peak of the gain fiber, and uses the dispersion management technique to broaden the optical spectrum up to 30 nm. The spectrum is maintained during the amplification and the pulse is compressed by single-mode fibers. The SHG imaging performance is showcased on a mouse skull, leg, and tail. Two-photon fluorescence imaging is also demonstrated on C. elegans labeled with green and red fluorescent proteins. The frequency-doubled all-fiber laser system provides a compact and efficient tool for SHG and fluorescence microscopy.


Asunto(s)
Caenorhabditis elegans , Rayos Láser , Animales , Ratones , Microscopía Fluorescente , Imagen Óptica , Fotones
13.
Artículo en Inglés | MEDLINE | ID: mdl-35564556

RESUMEN

Ultrafine particles (UFPs) significantly affect human health and climate. UFPs can be produced largely from the incomplete burning of solid fuels in stoves; however, indoor UFPs are less studied compared to outdoor UFPs, especially in coal-combustion homes. In this study, indoor and outdoor UFP concentrations were measured simultaneously by using a portable instrument, and internal and outdoor source contributions to indoor UFPs were estimated using a statistical approach based on highly temporally resolved data. The total concentrations of indoor UFPs in a rural household with the presence of coal burning were as high as 1.64 × 105 (1.32 × 105-2.09 × 105 as interquartile range) #/cm3, which was nearly one order of magnitude higher than that of outdoor UFPs. Indoor UFPs were unimodal, with the greatest abundance of particles in the size range of 31.6-100 nm. The indoor-to-outdoor ratio of UFPs in a rural household was about 6.4 (2.7-16.0), while it was 0.89 (0.88-0.91) in a home without strong internal sources. A dynamic process illustrated that the particle number concentration increased by ~5 times during the coal ignition period. Indoor coal combustion made up to over 80% of indoor UFPs, while in an urban home without coal combustion sources indoors, the outdoor sources may contribute to nearly 90% of indoor UFPs. A high number concentration and a greater number of finer particles in homes with the presence of coal combustion indicated serious health hazards associated with UFP exposure and the necessity for future controls on indoor UFPs.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire Interior , Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Carbón Mineral , Monitoreo del Ambiente , Humanos , Tamaño de la Partícula , Material Particulado/análisis
14.
Sci Total Environ ; 838(Pt 2): 156148, 2022 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-35609688

RESUMEN

Comparison of microbial community diversity and composition of terrestrial and aquatic ecosystems in undisturbed regions could expand our understanding on the mechanisms of microbial community assembly and ecosystem responses to environmental change. This study investigated the spatial distribution of bacterial community diversity and composition in the lakeshore soils and lake sediments from one of the best preserved nature reserves, Hoh Xil on the Qinghai-Tibetan Plateau, and explored the corresponding environmental drivers. A total of 36 sediment and soil samples were collected from six alpine lakes and the corresponding shore zones, and their bacterial community structure was identified by high-throughput 16S rRNA gene sequencing. Significant difference (p < 0.05) in diversity and composition of bacterial communities between the soils and sediments was observed. Heterogeneous selection played a dominant role in shaping the spatial variations of bacterial communities between the soils and sediments. Results of canonical correspondence analysis showed that the difference in composition of bacterial communities at OTU level between the soils and sediments was mainly determined by the mean annual temperature, salinity, and contents of total organic carbon and total nitrogen. Structural equation modeling revealed that salinity played a significantly direct role in soil bacterial composition, while mean annual temperature indirectly affected the bacterial composition mainly through changing soil salinity. In contrast, the sediment bacterial composition was directly influenced primarily by the contents of total organic carbon and total nitrogen, while pH also had an important indirect effect on sediment bacterial composition. These results shed light on the distribution patterns of bacterial communities between lakeshore soils and lake sediments in high-altitude permafrost regions, and the major ecological processes and environmental drivers that shaped their bacterial communities, and provide insight into the mechanisms underlying microbial community assembly in such regions.


Asunto(s)
Lagos , Microbiota , Bacterias/genética , Carbono , Lagos/química , Nitrógeno , ARN Ribosómico 16S/genética , Suelo , Microbiología del Suelo , Tibet
15.
Opt Lett ; 47(8): 1968-1971, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35427313

RESUMEN

The breathing dissipative soliton as a dynamic solution to many nonlinear systems has induced substantial interest in nonlinear photonics and ultrafast laser science. However, the exotic breathing multi-soliton dynamics are still largely unexplored in the bidirectional fiber laser compared to the unidirectional laser. Here, we reveal nonequilibrium dynamics of a breathing soliton pair (BSP) with energy transfer in a bidirectional laser; in particular, the dissociation and annihilation of the BSP was triggered by control over intra-cavity polarization. Optical rogue waves were detected simultaneously, and the collision of breathers significantly increased the intensity of rogue waves, which is characteristic of the bidirectional laser. Further, the buildup dynamics of the BSP with nanosecond pulse separation and a breathing soliton molecule were observed. Multiple single soliton explosions and transient pulse splitting are distinct features of soliton molecule buildup compared to the soliton pair. These findings shed new insights into the multiple breather dynamics of nonlinear systems.

16.
Opt Lett ; 47(8): 2048-2051, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35427333

RESUMEN

Two-photon microscopy (TPM) offers deeper imaging depth inside the scattering medium, however, it suffers from limited resolution owing to the longer excitation wavelength. We demonstrate the use of a hollow Gaussian beam (HGB) at the therapeutic window to improve the resolution and signal-to-background ratio (SBR). The HGB was produced by omitting the azimuthal phase term from the vortex mode, and the excitation point spread function (PSF) can be readily tuned by the mode order. The performance of the TPM with HGB was evaluated by experimentally imaging 100 nm fluorescent beads to estimate the PSF. The HGB improved the lateral resolution of the TPM by 36% in contrast to the conventional TPM. The HGB also furnishes an improvement of SBR by eliminating the out-of-focus light owing to its ring shape. Furthermore, we have used a translating lens-based module for additional lateral resolution tuning and reduced the resolution further down to 44% with respect to conventional TPM. Finally, we have performed imaging with merely two-dimensional scanning of a 50 µm thick mouse brain slice (Thy-YFP H-line) using the developed TPM with HGB. Our compact, robust, and low-cost design of the HGB generation scheme can easily be integrated into the commercial TPM to accommodate the improvements.


Asunto(s)
Microscopía , Fotones , Animales , Ratones , Microscopía/métodos , Distribución Normal
17.
Appl Opt ; 61(1): 149-156, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-35200814

RESUMEN

This paper presents a single-beam atomic magnetic field measurement gradiometer, which is a highly sensitive magnetic field gradient measuring instrument based on the atom spin-exchange relaxation-free (SERF) effect. The reflective detection optical path structure is adopted. The spin precession signals of an atom under incident and reflected light are different. There is also a difference in the corresponding magnetic field distribution. The final measurement of magnetic field gradients is conducted based on the different magnetic field distributions. The single-beam high-sensitive magnetic field gradiometers based on the atomic SERF effect are more sensitive than conventional two-probe magnetic field gradiometers or two-beam magnetic field gradiometers. The gradiometers are not affected by a difference in the detected optical power in the single-beam detection light measurements. The reflector uses an angular cone prism for two-dimensional magnetic field gradient measurements and is simple to construct. The single-beam highly sensitive magnetic field gradient measurement instrument based on the atomic SERF effect has a reflective detection optical path structure. It uses a quarter-wave plate to achieve the initial signal phase elimination of both incident and reflected signal and an angular cone prism as a reflector to achieve two-dimensional measurement.

18.
Int J Biol Macromol ; 204: 41-49, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35122797

RESUMEN

In the present work, cellulose nanocrystals (CNCs) composite films with suitable applicable capabilities were prepared by facilely incorporating glycerol (Gly) and poly(benzyl acrylate) (PBA). Chemical and morphological variations during the fabrication of the films were systematically characterized. The properties of modified CNCs composite films including UV blocking ability, mechanical strength and thermal properties were characterized to assess their applicable potentials. As a result, the composite films have good UV shielding property in UVC (220-280 nm) region and UVB (280-320 nm) region. The shielding performance of the modified film in the ultraviolet absorption region reached 92.77% to 95.49% respectively, without damaging the original chiral nematic structure of the films. Along with the modification, BACNC film improved the mechanical properties, presenting the tensile strength 16 times higher compared to pure CNCs film. The nanocomposite films proposed in this work showed promising potentials in broad fields, such as food preservation, medical protection, and surface coating applications.


Asunto(s)
Nanocompuestos , Nanopartículas , Acrilatos , Celulosa/química , Glicerol , Nanocompuestos/química , Nanopartículas/química
19.
Int J Biol Macromol ; 193(Pt B): 1324-1331, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34742850

RESUMEN

Herein, nanocomposites films were prepared via the facile casting method by incorporating cellulose nanocrystals (CNCs) with arabinogalactan (AG), galactomannan (GM) or konjac glucomannan (KGM) respectively. The introduced polysaccharides maintained the transparency of CNCs films and promoted the UV blocking properties. In addition, mechanical strength of the nanocomposite films was greatly improved after the combination of polysaccharides. The interactions of hydroxyl-abundant macromolecules, smoother and tighter morphological structures, as well as the disturbed crystal structure were proved to be responsible for the improved properties. Hydrophilic lattice planes of cellulose crystallites were determined to interact with polysaccharides resulting in lower crystallite sizes and crystallinity. The cell culture assay revealed that the films had no cytotoxicity and presented a satisfactory cytocompatibility, because of the polysaccharides from plant cell walls introduced into the films. Therefore, the biocompatible nanocomposites films can be tuned by the addition of polysaccharides, which show great potentials for materials modification in optical, packaging and biomedical fields.


Asunto(s)
Celulosa/química , Nanocompuestos/química , Nanopartículas/química , Módulo de Elasticidad , Galactosa/análogos & derivados , Galactosa/química , Mananos/química , Permeabilidad , Polisacáridos/química , Resistencia a la Tracción
20.
Small ; 17(49): e2103521, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34655150

RESUMEN

The ultrastretchable (over 12 400%) hydrogel with long-lasting adhesion, strong antibacterial activity, and robust spinnability is developed based on the oxidative decarboxylation and quinone-catechol reversible redox reaction induced by Ag-lignin nanoparticles in a precursor solution containing citric acid (CA), acrylic acid (AA), and poly (acrylamide-co-acrylic acid) (P(AAm-co-AA)). With massive reversible interactions including hydrogen bonds and electrostatic forces, such hydrogel exhibits promising injectability and is facilely spun via manual drawing, draw-spinning, and electrospinning for manufacturing strong hydrogel micro/nanofibers. The resulting fibers exhibit excellent mechanical properties, including tensile stress of 422.0 MPa, strain of 86.5%, Young's modulus of 8.7 GPa, and toughness of 281.6 MJ m-3 . The hydrogel microfibers obtained from a house-built spinner are scaled-up fabricated while retaining promising mechanical properties, as evidenced by lifting a load (317.2 g) using the spun fibers of ≈33 000 times lighter weight (9.5 mg), indicating their great potentials in the applications such as net and safety cord which require robust mechanical properties. Moreover, assisted by a commercial electrospinning machine, nanosized hydrogel fibers are facilely spun on personal protective equipment such as a mask to offer an antiseptic coating with near 100% killing efficiency against airborne bacteria aerosols, demonstrating the capability of spun hydrogel fibers on disinfection-related applications.


Asunto(s)
Nanofibras , Adhesivos , Antibacterianos/farmacología , Módulo de Elasticidad , Hidrogeles
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...