Continuing efforts have been made to explore novel exopolysaccharides (EPSs) for valuable applications. In this research, we report for the first time that a novel non-glucan EPS named EPS-605 can self-assemble to form spherical nanosize particles of ∼88 nm in diameter, expanding both the range of EPS type and structural type that EPSs self-assemble into. Characterization of EPS-605 shows that it is composed of mannose, glucose, and galactose with several modifications including acylation, phosphorylation, sulfation, and carboxylation, and a highly negative charge. EPS-605 showed a record biosorption capability for Pb, Cu, Cd, and methylene blue as compared to that of other reported EPSs, biosorbents, and nanosorbents. The adsorption ability of EPS-605 is affected by pH, temperature, the initial adsorbate concentration, the contact time, and the presence of background electrolytes. The mechanism of EPS-605 adsorbing heavy metals seems to be different to that for dyes. Moreover, EPS-605 can serve as the reductant in the synthesis of Au nanoparticles (AuNPs) and AgNPs enabling good monodispersity within the shortest time (of 30 min) compared to that from other EPSs and without any extra pretreatment. Our research advances the development of novel EPSs and provides a new, eco-friendly, and renewable platform for both the bioremediation and green synthesis of nanomaterials.

The miniaturization of electronic devices and power systems for capacitive energy storage under harsh environments requires scalable high‐quality ultrathin high‐temperature dielectric films. To meet the need, ultrasonic spray‐coating (USC) can be used. Novel polyimides with a dipolar group, CF3 (F‐PI), and all‐organic composites with trace organic semiconductor can serve as models. These scalable high‐quality ultrathin films (≈2.6 and ≈5.2 µm) are successfully fabricated via USC. The high quality of the films is evaluated from the micro‐millimeter scale to the sub‐millimeter and above. The high glass transition temperature Tg (≈340 °C) and concurrent large bandgap Eg (≈3.53 eV) induced by weak conjugation from considerable interchain distance (≈6.2 Å) enable F‐PI to be an excellent matrix delivering a discharge energy density with 90% discharge efficiency Uη90 of 2.85 J cm−3 at 200 °C. Further, the incorporation of a trace organic semiconductor leads to a record Uη90 of ≈4.39 J cm−3 at 200 °C due to the markedly enhanced breakdown strength caused by deep charge traps of ≈2 eV. Also, a USC‐fabricated multilayer F‐PI foil capacitor with ≈85 nF (six layers) has good performance at 150 °C. These results confirm that USC is an excellent technology to fabricate high‐quality ultrathin dielectric films and capacitors.

Polymer dispersed liquid crystals (PDLCs) have kindled a spark of interest because of their unique characteristic of electrically controlled switching. However, some issues including high operating voltage, low contrast ratio and poor mechanical properties are hindering their practical applications. To overcome these drawbacks, some measures were taken such as molecular structure optimization of the monomers and liquid crystals, modification of PDLC and doping of nanoparticles and dyes. This review aims at detailing the recent advances in the process, preparations and applications of PDLCs over the past six years.

Polymer dielectrics with excellent thermal stability are the essential core material for thin film capacitors applied in a harsh‐environment. However, the dielectric and mechanical properties of polymers are commonly deteriorated with temperature rising. Herein, polyetherimide (PEI)‐based nanocomposites contained with SiO2 nanoparticles (SiO2‐NPs) are fabricated by a solution casting method. It is found that the introduction of SiO2‐NPs decreases the electric conductivity and significantly enhances the breakdown strength of the nanocomposites, especially under high temperatures. As a result, the 5 vol% PEI/SiO2‐NPs nanocomposite film displays a superior dielectric energy storage performance, e.g., a discharged energy density of 6.30 J cm‐3 and a charge–discharge efficiency of 90.5% measured at 620 MV m‐1 and 150 °C. In situ scanning Kelvin probe microscopy characterization indicates that the charge carriers can be trapped in the interfacial regions between the polymer matrix and the SiO2‐NPs till the temperature reaches as high as 150 °C. This work demonstrates an effective strategy to fabricate high‐temperature dielectric polymer nanocomposites by embedding inorganic nanoparticles and provides a method for directly detecting charge behavior at the nanoscale inside the matrix.

BackgroundThe induction of cellulase production by insoluble carbon source cellulose was a common and efficient strategy, but has some drawbacks, such as difficult fermentation operation, substantial cellulase loss, long fermentation time, and high energy-consumption, resulting in high cost of cellulase production in industry. These drawbacks can be overcome if soluble carbon sources are utilized as the inducers for cellulase production. However, until now the induction efficiency of most soluble carbon sources, especially lactose and glucose, is still inferior to cellulose despite extensive efforts have been made by either optimizing the fermentation process or constructing the recombinant strains. Therefore, strain improvement by metabolic engineering for high induction efficiency of soluble carbon sources is of great interest.Results Trichoderma reesei mutant SEU-7 was constructed from T. reesei RUT-C30 with the overexpression of endogenous gene β-glucosidase (BGL1) by insertional mutagenesis via Agrobacterium tumefaciens-mediated transformation (AMT). Compared to RUT-C30, SEU-7 displays substantially enhanced activities of both cellulase and hemicellulase when grown on either lactose or cellulose. The induction efficiency with lactose was found to be higher than cellulose in strain SEU-7. To the best of our knowledge, we achieved the highest FPase activity in SEU-7 in both batch culture (13.0 IU/mL) and fed-batch culture (47.0 IU/mL) on lactose. Moreover, SEU-7 displayed unrivaled pNPGase activity on lactose in both batch culture (81.0 IU/mL) and fed-batch culture (144.0 IU/mL) as compared to the other reported T. reesei strains in the literature grown in batch or fed-batch experiments on cellulose or lactose. This superiority of SEU-7 over RUT-C30 improves markedly the saccharification ability of SEU-7 on pretreated corn stover. The overexpression of gene BGL1 was found either at the mRNA or at the protein level in the mutant strains with increased cellulase production in comparison with RUT-C30, but only SEU-7 displayed much higher expression of gene BGL1 on lactose than on cellulose. Two copies of gene BGL1 were inserted into the chromosome of T. reesei SEU-7 between KI911141.1:347357 and KI911141.1:347979, replacing the original 623-bp fragment that is not within any genes’ coding region. The qRT-PCR analysis revealed that the mRNA levels of both cellulase and hemicellulase were upregulated significantly in SEU-7, together with the MFS transporter CRT1 and the XYR1 nuclear importer KAP8.ConclusionsRecombinant T. reesei SEU-7 displays hyper-production of both cellulase and hemicellulase on lactose with the highest FPase activity and pNPGase activity for T. reesei, enabling highly efficient saccharification of pretreated biomass. For the first time, the induction efficiency for cellulase production by lactose in T. reesei was reported to be higher than that by cellulose. This outperformance of T. reesei SEU-7, which is strain-specific, is attributed to both the overexpression of gene BGL and the collateral ...

Utilization of distinct photoresponsive behaviour of p-aminodiphenylimide and multi-walled carbon nanotube, we design a wavelength-selective multicomposite featuring remotely controlled, microlocalized and photo-manipulating shape-memory behaviors based on typical three segments that are neat epoxy, p-aminodiphenylimide/epoxy and multi-walled carbon nanotube/epoxy composites. Herein, paminodiphenylimide and multi-walled carbon nanotube not only act as photoabsorbers and heat sources to 10 induced shape-memory effect but also functional component to manipulate shape-memory behaviors. In our concept, the quantity of temporary shape and shape recovery process in shape-memory cycle can be accurately controlled by photo-manipulating procedure. Moreover, only one switching domain with sharp thermal transition and a simple shape programming process similar to that for thermal-responsive dualshape shape-memory polymers are required to enable wavelength-selective multicomposite to represent 15 triple-or multi-shape-memory effect. This strategy can be put forward applications of shape-memory polymers and be applied in other stimulus-responsive system to generate complex structures.

Frequent itemset mining (FIM) plays an essential role in mining associations, correlations and many other important data mining tasks. Unfortunately, as the volume of dataset gets larger day by day, most of the FIM algorithms in literature become ineffective due to either too huge resource requirement or too much communication cost. In this paper, we propose a balanced parallel FP-Growth algorithm BPFP, based on the PFP algorithm [1], which parallelizes FP-Growth in the MapReduce approach. BPFP adds into PFP load balance feature, which improves parallelization and thereby improves performance. Through empirical study, BPFP outperformed the PFP which uses some simple grouping strategy.

Practical application of surface-enhanced Raman spectroscopy (SERS) is greatly limited by the inaccurate quantitative analyses due to the measuring parameter’s fluctuations induced by different operators, different Raman spectrometers, and different test sites and moments, especially during the field tests. Herein, we develop a strategy of quantitative SERS for field detection via designing structurally homogeneous and ordered Ag-coated Si nanocone arrays. Such an array is fabricated as SERS chips by depositing Ag on the template etching-induced Si nanocone array. Taking 4-aminothiophenol as the typical analyte, the influences of fluctuations in measuring parameters (such as defocusing depth and laser powers) on Raman signals are systematically studied, which significantly change SERS measurements. It has been shown that the silicon underneath the Ag coating in the chip can respond to the measuring parameters’ fluctuations synchronously with and similar to the analyte adsorbed on the chip surface, and the normalization with Si Raman signals can well eliminate the big fluctuations (up to 1 or 2 orders of magnitude) in measurements, achieving highly reproducible measurements (mostly, <5% in signal fluctuations) and accurate quantitative SERS analyses. Finally, the simulated field tests demonstrate that the developed strategy enables quantitatively analyzing the highly scattered SERS measurements well with 1 order of magnitude in signal fluctuation, exhibiting good practicability. This study provides a new practical chip and reliable quantitative SERS for the field detection of real samples.