Ultrasonic-Assisted Method for the Preparation of Carbon Nanotube-Graphene/Polydimethylsiloxane Composites with Integrated Thermal Conductivity, Electromagnetic Interference Shielding, and Mechanical Performances.

Due to the rapid development of the miniaturization and portability of electronic devices, the demand for polymer composites with high thermal conductivity and mechanical flexibility has significantly increased. A carbon nanotube (CNT)-graphene (Gr)/polydimethylsiloxane (PDMS) composite with excellent thermal conductivity and mechanical flexibility is prepared by ultrasonic-assisted forced infiltration (UAFI). When the mass ratio of CNT and Gr reaches 3:1, the thermal conductivity of the CNT-Gr(3:1)/PDMS composite is 4.641 W/(m·K), which is 1619% higher than that of a pure PDMS matrix. In addition, the CNT-Gr(3:1)/PDMS composite also has excellent mechanical properties. The tensile strength and elongation at break of CNT-Gr(3:1)/PDMS composites are 3.29 MPa and 29.40%, respectively. The CNT-Gr/PDMS composite also shows good performance in terms of electromagnetic shielding and thermal stability. The PDMS composites have great potential in the thermal management of electronic devices.

Clinical efficacy of melatonin as adjunctive therapy to non-surgical treatment of periodontitis: a systematic review and meta-analysis.

OBJECTIVE: This study aimed to evaluate the effect of adjunctive melatonin supplementation on clinical outcomes after non-surgical periodontal treatment. METHODS: PubMed, Embase, and Web of Science databases were systematically searched for randomised controlled trials (RCTs) of melatonin adjuvant therapy for periodontitis from inception until May 2021. The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and registered on The International Prospective Register of Systematic Reviews (PROSPERO) (CRD42021250630). The risk of bias of included studies was assessed according to the Cochrane Handbook for Systematic Reviews of Interventions. The pooled effect estimates were calculated by a random-effects model, and results were expressed as weighted mean differences (WMD). RESULTS: Seven RCTs comprising 412 participants were included in the meta-analysis. The pooled results showed that adjuvant use of melatonin for non-surgical periodontal treatment significantly improved the probing depth (PD) [WMD = - 1.18, 95% CI (- 1.75, - 0.62) I2 = 85.7%], clinical attachment loss (CAL) [WMD = - 1.16, 95% CI (- 1.60, - 0.72) I2 = 76.7%] and gingival index (WMD = - 0.29, 95%CI [- 0.48, - 0.11], I2 = 63.6%) compared with non-surgical treatment alone. In addition, subgroup analysis showed that higher doses of melatonin (3-10 mg) significantly improved PD [WMD = - 1.32, 95%CI (- 2.31, - 0.15) I2 = 93%] and CAL [WMD = - 1.30, 95%CI (- 1.80, - 0.81) I2 = 73.7%] compared with lower doses of melatonin (< 3 mg). CONCLUSIONS: We found that adjunctive melatonin supplementation can significantly improve the periodontal status after non-surgical treatment, suggesting that melatonin may be a new adjuvant therapy for periodontitis when non-surgical periodontal treatment alone cannot achieve the desired improvement.

A New Family of Photoluminescent Polymers with Dual Chromophores.

A new family of photoluminescent polymers with dual chromophores is prepared in this study by using poly(maleic anhydride-alt-vinyl acetate), acetone, and metal hydroxide. These polymers, which contain both bulky carboxylic ester groups and metal carboxylate groups, are found to be dual-emission photoluminescent, with a blue luminescence excitation-dependent group and a red luminescence excitation-independent group. These photoluminescence polymers with a nonconjugated structure and dual chromophores also show characteristics of aggregation-induced emission (AIE). The luminous intensities of the AIE fibers prepared using the polymers are found to increase after stretching, in contrast to traditional photoluminescent fibers with the aggregation-caused quenching property. The study also finds that the stretched fibers can emit the three primary colors when irradiated by ultraviolet, blue, and green light.

Water-Soluble Polymers with Strong Photoluminescence through an Eco-Friendly and Low-Cost Route.

Photoluminescence (PL) of nonconjugated polymers brings a favorable opportunity for low-cost and nontoxic luminescent materials, while most of them still exhibit relatively weak emission. Strong PL from poly[(maleic anhydride)-alt-(vinyl acetate)] (PMV) from low-cost monomer has been found in organic solvents, yet the necessity of noxious solvents would hinder its practical applications. Herein, through a novel, eco-friendly, and one-step route, PMV-derived PL polymers can be fabricated with the highest quantum yield of 87% among water-soluble nonconjugated PL polymers ever reported. These PMV-derived polymers emit strong blue emission in both solutions and solids, and can be transformed into red-emission agents easily. These PL polymers exhibit application potentials in light-conversion agricultural films. It is assumed that this work not only puts forward a convenient preparation routine for nonconjugated polymers with high PL, but also provides an industrial application possibility for them.

A Review of Structure Construction of Silk Fibroin Biomaterials from Single Structures to Multi-Level Structures.

The biological performance of artificial biomaterials is closely related to their structure characteristics. Cell adhesion, migration, proliferation, and differentiation are all strongly affected by the different scale structures of biomaterials. Silk fibroin (SF), extracted mainly from silkworms, has become a popular biomaterial due to its excellent biocompatibility, exceptional mechanical properties, tunable degradation, ease of processing, and sufficient supply. As a material with excellent processability, SF can be processed into various forms with different structures, including particulate, fiber, film, and three-dimensional (3D) porous scaffolds. This review discusses and summarizes the various constructions of SF-based materials, from single structures to multi-level structures, and their applications. In combination with single structures, new techniques for creating special multi-level structures of SF-based materials, such as micropatterning and 3D-printing, are also briefly addressed.

Porous fibrous bacterial cellulose/La(OH)3 membrane for superior phosphate removal from water.

Lanthanum (La)-based nanoparticles (NPs) are promising candidates for phosphate removal owing to their inherently high affinity towards phosphate. However, significant challenges remain to be addressed before their practical deployment, especially the problems associated with their aggregation. Herein, we fabricated a high-efficient sorbent for phosphate removal through in-situ synthesizing La(OH)3 NPs on a natural support, bacterial cellulose (BC), which is pre-modified with polyethyleneimine. The resultant La(OH)3 NPs-immobilized BC with different La contents (BPLa-X) exhibited a highly fibrous porous structure, in which BPLa-3 was selected for further phosphate adsorption studies. BPLa-3 demonstrated a high adsorption capacity of 125.5 mg P g-1, and high adsorption selectivity due to the large surface area and abundant exposed active adsorption sites for phosphate. Additionally, BPLa-3 also displayed high reusability and still possessed high adsorption capacity after four consecutive cycles of adsorption-desorption. Therefore, the present adsorbent is believed to be a promising candidate for practical phosphate removal.

Features correlated to improved enzymatic digestibility of corn stover subjected to alkaline hydrogen peroxide pretreatment.

As one of the leading pretreatment approaches, alkaline hydrogen peroxide (AHP) pretreatment can enhance the enzymatic digestibility of lignocellulose significantly. In this study, the glucan conversion of AHP pretreated corn stover (CS) without and with water-wash were 28.4% and 50.0% higher than that of raw material, respectively. In order to systematically understand its mechanism, analyses of the features of AHP pretreated and raw CS, such as specific surface area, crystallinity, zeta potential, water holding capacity and swelling capacity and others were performed. The weight-average molecular weight (Mw) of the sugars in the hydrolysate and the particle size distribution of the hydrolysis residue were also analyzed. These results explained why AHP-CS was more conducive to enzymatic hydrolysis. The deeper reason was that the removal of lignin and the destruction of hydrogen bonds within cellulose and hemicellulose increased the accessibility of cellulose and reduced the non-productive adsorption of cellulase, which significantly improved the enzymatic digestibility.

Tuning the surface microstructure of titanate coatings on titanium implants for enhancing bioactivity of implants.

Biological performance of artificial implant materials is closely related to their surface characteristics, such as microtopography, and composition. Therefore, convenient fabrication of artificial implant materials with a cell-friendly surface structure and suitable composition was of great significance for current tissue engineering. In this work, titanate materials with a nanotubular structure were successfully fabricated through a simple chemical treatment. Immersion test in a simulated body fluid and in vitro cell culture were used to evaluate the biological performance of the treated samples. The results demonstrate that the titanate layer with a nanotubular structure on Ti substrates can promote the apatite-inducing ability remarkably and greatly enhance cellular responses. This highlights the potential of such titanate biomaterials with the special nanoscale structure and effective surface composition for biomedical applications such as bone implants.