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1.
Int J Biol Macromol ; 265(Pt 2): 131143, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38537861

RESUMEN

Hydrogel electrolyte is an ideal candidate material for flexible energy storage devices due to its excellent softness and conductivity properties. However, challenges such as the inherent mechanical weakness, the susceptibility to be frozen in low-temperature environments, and the insufficiency of hydrogel-electrode contact persist. Herein, a "Multi in One" strategy is employed to effectively conquer these difficulties by endowing hydrogels with high strength, freeze-resistance, and self-adhesive ability. Multiple hydrogen bond networks and ion crosslinking networks are constructed within the hydrogel electrolyte (PVA/PAAc/XG) containing polyvinyl alcohol (PVA), acrylic acid (AAc), and xanthan gum (XG), promoting the enhanced mechanical property, and the adhesion to electrode materials is also improved through abundant active groups. The introduction of zinc ions provides the material with superior frost resistance while also promoting electrical conductivity. Leveraging its multifunction of superior mechanical strength, anti-freeze property, and self-adhesive characteristic, the PVA/PAAc/XG hydrogel electrolyte is employed to fabricate zinc ion hybrid supercapacitors (ZHS). Remarkably, ZHS exhibits outstanding electrochemical performance and cycle stability. A remarkable capacity retention rate of 83.86 % after 10,000 charge-discharge cycles can be achieved at high current densities, even when the operational temperature decreases to -60 °C, showing great potential in the field of flexible energy storage devices.


Asunto(s)
Polisacáridos Bacterianos , Cementos de Resina , Zinc , Hidrogeles , Electrólitos , Iones
2.
Carbohydr Polym ; 313: 120813, 2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37182943

RESUMEN

Self-healing, self-adhesive, and stretchable bio-based conductive hydrogels exhibit properties similar to those of biological tissues, making them an urgent requirement for emerging wearable devices. The primary challenge lies in devising straightforward strategies to accomplish all the aforementioned performances and achieve equilibrium among them. This study used the natural compound thioctic acid (TA) and modified cellulose to prepare conductive hydrogels with stretchability, healing, and self-adhesion through a simple one-step strategy. Metastable poly(TA) was obtained through ring-opening polymerization of lithiated TA, followed by the introduction of dopamine-grafted cellulose nanofibers (DCNF) to stabilize poly(TA) and prepare PTALi/DCNF hydrogels with the aforementioned properties. The hydrogels demonstrated remarkable conductivity, attributed to the existence of Li + ions, with a maximum conductivity of 17.36 mS/cm. The self-healing capacity of the hydrogels was achieved owing to the presence of disulfide bond in TA. The introduction of DCNF can effectively stabilize poly(TA), endow the hydrogel with self-adhesion ability, improve the mechanical properties, and further enhance the formability of hydrogels. Generally, bio-based PTALi/DCNF hydrogels with stretchability, self-healing, self-adhesion, and conductivity are obtained through a simple strategy and used as a sensor with a wide response range and high sensitivity. Hydrogels have significant potential for application in wearable electronic devices, electronic skins, and soft robots.

3.
Artículo en Inglés | MEDLINE | ID: mdl-36193150

RESUMEN

The efficacy of massage therapy in the treatment of children with autism spectrum disorder (ASD) remains unclear. This study systematically reviewed the impact of massage therapy on children with ASD according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) declaration guidelines. A literature search of the PubMed, Web of Science, Science Direct, Scopus, Google Scholar, and China National Knowledge Infrastructure (CNKI) electronic databases from inception to December 20, 2020, was conducted using the term "autistic/autism" along with one of the following terms, "massages," and "Tui na." The risk of bias was assessed using the Cochrane risk of bias Tool. Eight randomized controlled trials examining the impact of massage on children with ASD were included. Interventions combining Qigong massage or Tui na with the control group treatments from once a day to twice a week, for a duration of 15-30 mins, and lasting for six weeks to five months were the main interventions. All reviewed studies reported significant improvement in children with ASD who received massage, especially in the sensory domain, and that massage in combination with control treatment was superior to control treatment alone. However, the overall quality of the available studies is poor with a high degree of heterogeneity. The majority of studies showed a high risk of bias with poor study design, inconsistency in massage protocols, and subjective outcome measures. Assessment bias was a common weakness of these studies. Therefore, there is insufficient evidence to conclude that massage is effective for ASD. Future studies should include large sample sizes, incorporate double-blind designs, employ appropriate outcome measures, and allow for long observation and follow-up periods. Furthermore, consensus must be reached on standardized treatments and additional therapies in order to provide better quality evidence for the treatment of ASD.

4.
Biomacromolecules ; 23(7): 2856-2866, 2022 07 11.
Artículo en Inglés | MEDLINE | ID: mdl-35694860

RESUMEN

Low-k dielectrics are urgently needed in modern integrated circuits. The introduction of free volume instead of porous structures has become a powerful strategy to reduce the k value. According to this strategy, the biomass resource rosin-containing hydrogenated phenanthrene ring was introduced into benzocyclobutene (BCB) resin to reduce the k value; then a rosin-based BCB monomer was successfully synthesized. Meanwhile, the BCB monomer without a rosin skeleton was prepared. After converting the monomers into thermo-crosslinked materials, notably that the rosin skeleton has a great influence on the free volume and k value of the material. The fractional free volume and k value of the former are 26% and 2.44, respectively, and those of the latter are 14% and 2.84, respectively. In addition, the distances between molecular chains and the density of the former are 0.60 nm and 1.06 g cm-3, respectively; those of the latter are 0.56 nm and 1.28 g cm-3, respectively. These data show that introducing hydrogenated phenanthrene rings occupies part of the space and hinders the packing of molecular chains, which increases the distance between molecular chains and reduces the density of the polymer, resulting in an increasing free volume and a reducing k value. Notably that introducing hydrogenated phenanthrene rings cannot affect other properties of the material. Therefore, this research indicates that introducing rosin skeletons can prepare high-performance materials, which provide some promising low-k materials for the development of electronics and microelectronics.


Asunto(s)
Fenantrenos , Resinas de Plantas , Fenantrenos/química , Polímeros , Resinas de Plantas/química
5.
RSC Adv ; 9(51): 29788-29795, 2019 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-35531539

RESUMEN

Development of bio-based polymers has been promoted by the growing concerns about the long-term sustainability and negative environmental footprint of petroleum-based polymer materials. A new monomer containing benzocyclobutene and allyl units has been developed by using rosin as the feedstock. The structure of the monomer was characterized by elemental analysis, MS, FT-IR and NMR spectroscopy. The monomer could be converted to the polymer via thermal ring-opening polymerization which was characterized via FT-IR, thermogravimetric analysis (TGA), atom force microscopy (AFM) and so on. The polymer showed good dielectric properties and hydrophobicity with an average dielectric constant of 2.51 in a range of frequencies from 0.1 to 18 MHz and a water contact angle of 106°. In addition, the polymer with other comprehensive performances exhibited a 5% weight loss temperature of 406 °C, a surface roughness (R a) of 0.658 nm in a 5.0 × 5.0 µm2 area, hardness and Young's modulus of 0.283 and 3.542 GPa, and storage modulus of 11.46 GPa at 30 °C. These data suggest that the polymer may have potential application in electronics and microelectronics.

6.
Carbohydr Polym ; 186: 132-139, 2018 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-29455970

RESUMEN

Cellulose nanofibrils (CNFs) were firstly prepared by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation and further oxidized to 2,3-dialdehyde nanocelluloses (DANCs) by periodate oxidation. Furthermore, by using DANCs as reducing as well as stabilizing agent, palladium (Pd) and gold (Au) nanoparticles (NPs) supported on nanocellulose (PdNPs@NC and AuNPs@NC) were synthesized, respectively. The reduction of Pd or Au ions to its metallic form by DANCs was confirmed by UV-vis spectra, XRD, and XPS. TEM results showed that Pd and Au NPs were homogenously deposited onto cellulose nanofibrils, respectively. The catalytic performance of PdNPs@NC was further investigated by Suzuki coupling reaction. The product yield of the Suzuki coupling reaction between aryl bromides and phenyl boronic acid was more than 90% after 1 h with 0.1 mol% PdNPs@NC catalyst, which demonstrated that the synthesized PdNPs@NC nanohybrid could be successfully applied in Suzuki coupling reaction with an efficient catalytic activity.

7.
J Agric Food Chem ; 65(17): 3497-3504, 2017 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-28418657

RESUMEN

An oil-in-water emulsion stabilized by saponified epoxidized soybean oil-grafted hydroxyethyl cellulose (H-ESO-HEC) was investigated. By using an ultrasonic method, oil-in-water emulsions were prepared by blending 50 wt % soybean oil and 50 wt % H-ESO-HEC aqueous suspensions. The influence of H-ESO-HEC concentrations on the properties of oil-in-water emulsions was examined. The H-ESO-HEC concentrations in the aqueous phase varied from 0.02 to 0.40 wt %. When the H-ESO-HEC concentration was 0.4 wt %, the emulsion remained stable for >80 days. The mean droplet sizes of the emulsions decreased by increasing the H-ESO-HEC concentration and extending the ultrasonic time. The adsorption amounts of H-ESO-HEC at the oil-water interface increased when the H-ESO-HEC concentrations in the aqueous phase increased. The rheological property revealed that the apparent viscosity of the H-ESO-HEC-stabilized oil-in-water emulsions increased when the H-ESO-HEC concentrations increased. Steady flow curves indicated an interfacial film formation in the emulsions. The evolution of G', G″, and tan η indicated the predominantly elastic behaviors of all the emulsions.


Asunto(s)
Celulosa/análogos & derivados , Aceite de Soja/química , Agua/química , Celulosa/química , Emulsiones/química , Reología , Viscosidad
8.
Bioorg Med Chem Lett ; 26(6): 1512-1515, 2016 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-26898336

RESUMEN

A series of novel 3-cyanopyridine derivatives of (-)-ß-pinene were designed and synthesized by one-pot four-component domino reactions. The targeted compounds were evaluated for their antimicrobial activity against four bacteria (Klebsiella pneumoniae, Enterobacter aerogenes, Staphylococcus aureus, Staphylococcus epidermidis) and a fungus (Candida albicans). The results showed that most of the minimal inhibitory concentrations (MICs) of these 3-cyanopyridine derivatives against the tested strains was in the range of 15.6-125 mg/L. Among these 3-cyanopyridine derivatives, the MICs of compound 5h against S. epidermidis and C. albicans were 15.6 mg/L, which revealed that compound 5h featured double fluoro substituents at meta- and para-position was the most active compound. In addition, the preliminary structure-activity relationship analysis indicated that the change of substituents on the pyridine ring and benzene ring of 3-cyanopyridine derivatives was an important factor for inducing antimicrobial activity. This research would promote the development of heterocyclic derivatives of ß-pinene with antimicrobial activity.


Asunto(s)
Antibacterianos/síntesis química , Antibacterianos/farmacología , Antifúngicos/síntesis química , Antifúngicos/farmacología , Compuestos Bicíclicos con Puentes/química , Compuestos Bicíclicos con Puentes/farmacología , Monoterpenos/química , Monoterpenos/farmacología , Piridinas/química , Antibacterianos/química , Antifúngicos/química , Bacterias/efectos de los fármacos , Monoterpenos Bicíclicos , Compuestos Bicíclicos con Puentes/síntesis química , Relación Dosis-Respuesta a Droga , Hongos/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Monoterpenos/síntesis química , Piridinas/farmacología , Estereoisomerismo , Relación Estructura-Actividad
9.
Mol Divers ; 13(2): 209-39, 2009 May.
Artículo en Inglés | MEDLINE | ID: mdl-19125343

RESUMEN

The new phase-separation and immobilization technique known as fluorous biphase system (FBS) has become an active topic among researchers in both industry and academia. A series of fluorous biphasic reactions catalyzed by Lewis acid-type metal perfluorooctanesulfonates and metal bis(perfluorooctanesulfonyl)amides are reviewed in this paper. The recent development of fluorous phase transfer catalyst (PTC) is also discussed.


Asunto(s)
Ácidos Alcanesulfónicos/química , Amidas/química , Flúor/química , Fluorocarburos/química , Transición de Fase , Catálisis , Compuestos Organometálicos/química
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