PBAT/PLA food packaging film containing sodium dehydroacetate-loaded diatomite as an antibacterial agent: Fabrication, water-gas regulation and long-acting antimicrobial mechanism.

Biodegradable food packaging films with good antimicrobial properties are highly sought after for prolonging the shelf-life of fruits and vegetables whilst minimizing waste streams originating from the food sector. In this work, a series of PBAT/PLA food packaging films containing sodium dehydroacetate-loaded diatomite (SD/D) as an antimicrobial agent were fabricated. Structural analyses showed that the sodium dehydroacetate was incorporated into the pores of the diatomite. A uniform dispersion of SD/D in the composite films effectively enhanced water and gas permeability, whilst also giving the films good mechanical properties. The slow release of SD endowed the composite films with long-acting antibacterial ability (>90 % bacteriostasis rate for E. coli and >85 % bacteriostasis rate for S. aureus). The composite films were able to effectively maintain the quality of banana fruits during storage at room temperature, encouraging their use in food applications where non-biodegradable petrochemical-derived packaging films have traditionally been used.

POSS(epoxy)8 reinforced poly (butylene adipate-co-terephthalate)/lignin biodegradable films: Fabrication, enhanced mechanical properties and UV aging resistance.

To reduce the white pollution, the eco-friendly biodegradable poly (butylene adipate-co-terephthalate) (PBAT)-based films had attracted increasing interests worldwide. However, the high-cost of the PBAT had limited the large-scale development and application. In this work, 10 wt% low-cost lignin was introduced into the PBAT to prepare composite films by melt blending and blow molding, and the POSS(epoxy)8 was selected as the compatibilizer to improve the compatibility of PBAT and lignin. The maximum tensile strength and the nominal strain at break subsequently increased by 48.2 % and 21.4 % respectively, while the water vapor permeability enhanced by 9.9 %. Furthermore, the UV aging resistance of PBAT/lignin films were significantly improved, with only 1 wt% POSS(epoxy)8 content. This work provides an efficient strategy to foster the end-user confidence in the low-cost and eco-friendly biodegradable polymer materials with efficient performance.

Reducing Lattice Thermal Conductivity of MnTe by Se Alloying toward High Thermoelectric Performance.

Lead-free manganese telluride has been considered to be a promising candidate for mid-temperature thermoelectric materials. In this work, we report point defect scattering-induced reduction of thermal conductivity in MnTe with Se alloying, fabricated by a facile method combining mechanical alloying and spark plasma sintering. A low lattice thermal conductivity of 0.56 W/mK was obtained for MnTe0.92Se0.08, which is quite close to the amorphous limits. A detailed Debye model analysis reveals the underlying mechanism of phonon scattering and well predicts the thermal conductivity with different contents of Se. Meanwhile, a slight increase of carrier concentration was also observed after Se alloying, accompanied by a variation of energy gap that may be associated with the competition among anions in trapping charges. Further Na doping leads to enhanced electrical transport properties, achieving a maximum ZT value of 1.03 at 873 K. An average ZT of 0.52 and a calculated efficiency of more than 9% also suggest the promising application of MnTe at medium temperatures.

Bi2Te3 single crystals with high room-temperature thermoelectric performance enhanced by manipulating point defects based on first-principles calculation.

Intrinsic Bi2Te3 is a representative thermoelectric (TE) material with high performance at low temperature, which enables applications for electronic cooling. However, antisite defects easily form in p-type Bi2Te3, resulting in the difficulty of further property enhancement. In this work, the formation energy of native point defects in Bi2Te3 supercells and the electronic structure of Bi2Te3 primitive unit cell were calculated using first-principles. The antisite defect Bi_Te1 has a lower formation energy (0.68 eV) under the Te-lack condition for p-type Bi2Te3. The effects of point defects on TE properties were investigated via a series of p-type Bi2Te3-x (x = 0, 0.02, 0.04, 0.06, 0.08) single crystals prepared by the temperature gradient growth method (TGGM). Apart from the increased power factor (PF∥) which originates from the increased carrier concentration (n ∥) and m*, the thermal conductivity (κ ∥) was also cut down by the increased point defects. Benefitting from the high PF∥ of 4.09 mW m-1 K-2 and the low κ ∥ of 1.77 W m-1 K-1, the highest ZT ∥ of 0.70 was obtained for x = 0.06 composition at 300 K, which is 30% higher than that (0.54) of the intrinsic Bi2Te3.

Highly Textured N-Type SnSe Polycrystals with Enhanced Thermoelectric Performance.

Thermoelectric materials, which directly convert heat into electricity based on the Seebeck effects, have long been investigated for use in semiconductor refrigeration or waste heat recovery. Among them, SnSe has attracted significant attention due to its promising performance in both p-type and n-type crystals; in particular, a higher out-of-plane ZT value could be achieved in n-type SnSe due to its 3D charge and 2D phonon transports. In this work, the thermoelectric transport properties of n-type polycrystalline SnSe were investigated with an emphasis on the out-of-plane transport through producing textural microstructure. The textures were fabricated using mechanical alloying and repeated spark plasma sintering (SPS), as a kind of hot pressing, aimed at producing strong anisotropic transports in n-type polycrystalline SnSe as that in crystalline SnSe. Results show that the lowest thermal conductivity of 0.36 Wm-1 K-1 was obtained at 783 K in perpendicular to texture direction. Interestingly, the electrical transport properties are less anisotropic and even nearly isotropic, and the power factors reach 681.3 µWm-1 K-2 at 783 K along both parallel and perpendicular directions. The combination of large isotropic power factor and low anisotropic thermal conductivity leads to a maximum ZT of 1.5 at 783 K. The high performance elucidates the outstanding electrical and thermal transport behaviors in n-type polycrystalline SnSe, and a higher thermoelectric performance can be expected with future optimizing texture in n-type polycrystalline SnSe.

Determination of kanamycin using a molecularly imprinted SPR sensor.

A kanamycin molecular imprinted SPR sensor was prepared with 4-vinylbenzeneboronic acid as the functional monomer, polyethylene glycol acrylate and 2,2'-azo isobutyl amidine hydrochloride as the crosslinker and the initiator, respectively. Underoptimumconditions, the responseperformance of the imprinted SPR sensor to kanamycin was evaluated. The imprinted sensor had a better imprinting effect and selectivity for kanamycin thanthe non-imprinted one. The linear range of imprinted sensor for kanamycin was from 1.0 × 10-7 to 1.0 × 10-5 mol/L (R2 = 0.9941). Based on a signal-to-noise ratio of 3, the detection limits of kanamycin were 4.33 × 10-8 mol/L for milk powder and 1.20 × 10-8 mol/L for honey, with the RSD as 1.18% and 0.31%, respectively.

Surface Plasmon Resonance Spectroscopy for Detection of S-Nitrosylated Proteins.

Protein S-nitrosylation, the NO-dependent regulatory mechanism, is a posttranslational modification of reactive cysteine thiols to form S-nitrosothiols. The biotin-switch technique (BST) has become a mainstay method for detection of S-nitrosylated proteins in biological samples. On the basis of BST, we describe a surface plasmon resonance (SPR) spectroscopy method for detecting S-nitrosylated proteins. This method can be applied for the indirect determination of S-nitrosylated proteins in biological samples.