Environmentally sensitive hydrogels have enormous potential in various applications. Some environmental variables, such as low pH and elevated temperatures, are found in the body. For this reason, ...either pH-sensitive and/or temperature-sensitive hydrogels can be used for site-specific controlled drug delivery. Hydrogels that are responsive to specific molecules, such as glucose or antigens, can be used as biosensors as well as drug delivery systems. Light-sensitive, pressure-responsive and electro-sensitive hydrogels also have the potential to be used in drug delivery and bioseparation. While the concepts of these environment-sensitive hydrogels are sound, the practical applications require significant improvements in the hydrogel properties. The most significant weakness of all these external stimuli-sensitive hydrogels is that their response time is too slow. Thus, fast-acting hydrogels are necessary, and the easiest way of achieving that goal is to make thinner and smaller hydrogels. This usually makes the hydrogel systems too fragile and they do not have mechanical strength necessary in many applications. Environmentally sensitive hydrogels for drug delivery applications also require biocompatibility. Synthesis of new polymers and crosslinkers with more biocompatibility and better biodegradability would be essential for successful applications. Development of environmentally sensitive hydrogels with such properties is a formidable challenge. If the achievements of the past can be extrapolated into the future, however, it is highly likely that responsive hydrogels with a wide array of desirable properties can be made.
Ionic iridium(III) complexes are emerging with great promise for organic electronic devices, owing to their unique features such as ease of molecular design and synthesis, excellent photophysical ...properties, superior redox stability, and highly efficient emissions of virtually all colors. Here, recent progress on new material design, regarding photo‐ and electroluminescence is highlighted, including several interesting topics such as: i) color‐tuning strategies of cationic iridium(III) complexes, ii) widespread utilization in phosphorescent light‐emitting devices fabricated by not only solution processes but also vacuum evaporation deposition, and iii) potential applications in data record, storage, and sercurity. Results on anionic iridium(III) complexes and “soft salts” are also discussed, indicating a new related subject. Finally, a brief outlook is suggested, pointing out that ionic iridium(III) complexes should play a more significant role in future organic electronic materials technology.
Ionic iridium(III) complexes show high promise for organic electronic devices owing to their excellent luminescence of virtually all colors. Recent progress on material design, characterization, and applications of ionic iridium(III) complexes is highlighted, pointing out their great potential for future organic displays, lighting, and data record storage.
This study constructed a 1000 L modularized MFC system, the largest volume so far, to treat practical municipal wastewater. This MFC system was operated under two different water flow connections in ...two municipal wastewater treatment plants (MWTP) for more than one year to test their treating abilities for wastewater with both low (average 80 mg L−1) and high initial COD concentration (average 250 mg L−1). The COD concentration in the effluent from the MFC system remained below 50 mg L−1 with a removal rate of 70–90%, which stably met the level A of the first class in discharge standard of pollutants for MWTP of China. A maximum power density of 125 W m−3 (7.58 W m−2) was generated when the MFC system was fed with artificial wastewater, while it lay in a range of 7–60 W m−3 (0.42–3.64 W m−2) when treating municipal wastewater. The energy recovery of 0.033 ± 0.005 kWh per m3 of municipal wastewater was achieved, with a hydraulic retention time (HRT) of 2 h.
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•Scaled-up (1000 L) MFC consisted of 50 modules was operated for a year.•The MFC was applied to treat artificial and real municipal wastewater.•Concentration of COD released was below 50 mg L−1 with a removal rate of 70–90%.•The maximum power density harvested from municipal wastewater was 7–60 W m−3.
Organic light‐emitting diodes (OLEDs) have attracted great attention because of their potential applications in full‐color displays and solid‐state lights. In the continual effort to search for ideal ...materials for OLEDs, small molecules with bipolar transporting character are extremely attractive as they offer the possibility to achieve efficient and stable OLEDs even in a simple single‐layer device. In this Research News, we review the two design strategies of bipolar materials for OLEDs: molecules with or without donor‐acceptor structures. The correlation between the experimental results and theoretical calculations of some of the materials is also discussed.
Small molecules with bipolar transporting characters are extremely attractive as they offer the possibility to achieve efficient and stable organic light‐emitting diodes (OLEDs). In this article we review the two design strategies for bipolar materials for OLEDs: with or without donor‐acceptor structure. The correlation between the experimental results and theoretical calculations of some of the materials is also discussed.
The spread of antibiotic resistance genes (ARGs) has become an emerging threat to the global health. Although horizontal gene transfer (HGT) is regarded as one of the major pathways, more evidence ...has shown the significant involvement of vertical gene transfer (VGT). However, traditional cultivation-based methods cannot distinguish HGT and VGT, resulting in often contradictory conclusions. Here, single-cell microfluidics with time-lapse imaging has been successfully employed to dissect the contribution of plasmid-mediated HGT and VGT to ARG transmission in an environmental community. Using Escherichia coli with an ARG-coded plasmid pKJK5 with trimethoprim resistance as the donor, we quantified the effects of three representative antibiotics (trimethoprim, tetracycline and amoxicillin) on the ARG transfer process in an activated sludge bacterial community. It was found that HGT was influenced by the inhibitory mechanism of an antibiotic and its targets (donor, recipient alone or together), whereas VGT contributes significantly to the formation of transconjugants and consequently ARG spreading. Trimethoprim is highly resisted by the donor and transconjugants, and its presence significantly increased both the HGT and VGT rates. Although tetracycline and amoxicillin both inhibit the donor, they showed different effects on HGT rate as a result of different inhibitory mechanisms. Furthermore, we show the kinetics of HGT in a community can be described using an epidemic infection model, which in combination with quantitative measure of HGT and VGT on chip provides a promising tool to study and predict the dynamics of ARG spread in real-world communities.
•Dynamic plasmid transfer process was observed by cell tracking.•The dominancy of horizontal and vertical transfer pathways are difference.•Antibiotics stimulate and inhibit different aspects of plasmid transfer.•HGT was influenced by the inhibitory mechanism of an antibiotic and its targets.•Epidemic spread model can describe the kinetics of gene transmission via HGT.
► The granulation and heat recovery technologies towards molten slag of steel industry are reviewed. ► The working principle, research status, challenges and prospects of these technologies are ...analyzed. ► Centrifugal granulation combined with chemical heat recovery is the most perspective method among all technologies.
Molten slag exhausted with critically high temperature of about 1450–1550°C is a potential resource of energy and raw materials. Water quenching is a traditional heat recovery technology, which uses cold water to cool down slag so as to achieve the desired glassy by-products. However, this technology consumes a huge amount of water and fails to recover the sensible heat of slag. To save energy and reduce water consumption, some other heat recovery technologies have thus been proposed. Generally, current heat recovery technologies can be classified into physical and chemical methods. Regarding the physical methods, mechanical crushing, air blast and centrifugal granulating process, etc. are widely investigated. With respect to chemical methods, methane reforming reaction and coal gasification process, etc. are proposed. Unfortunately, all these methods cannot fulfill the sustainable requirement. This paper aims to review the proposed granulation and heat recovery technologies. Their working principle, current research status, challenges and future prospects are presented. The waste heat recovery and utilization technologies, which give consideration to both heat recovery rate and cooled slag particles with high quality and high additional value, will be a key to achieve sustainable development for the iron and steel industry.
Organic molecules consisting of electron donor (D) and electron acceptor (A) subunits linked by π-conjugated bridges are promising building blocks for thermally activated delayed fluorescence (TADF) ...and non-linear optics (NLO) materials due to their intramolecular charge transfer (CT) processes in response to external stimuli. According to the electron interaction pattern, the CT process in D-π-A architectures can be divided into two categories, through-bond/-space charge transfer (TB/TSCT). To date, research into the TADF properties of TSCT characteristic molecules has since seen significant growth. In fact, TSCT characteristic materials show great advantages in such NLO responses. In this perspective, we first briefly introduced the basic principles of NLO and TADF effects. Successively, we discuss the influence of TBCT and TSCT patterns on NLO and TADF properties, especially for TSCT characteristic. In the final part, we address the diversity and potential advantages of TSCT characteristic molecules as high-performance NLO materials. With these, it is expected that the greater structural flexibility of spatial conjugation can bring more functionality to NLO materials in the future.
In this perspective, we review the TADF properties of D-π-A molecules with through-space charge transfer architecture with focus on their regulating effects toward NLO responses.
The flame retardant epoxy resin has been prepared by mixing the flame retardant additive hexa-(phosphaphenanthrene-hydroxyl-methyl-phenoxyl)-cyclotriphosphazene (HAP-DOPO) into diglycidyl ether of ...bisphenol-A (DGEBA). After cured by 4,4′-Diamino-diphenyl sulfone (DDS), the flame retardant properties of thermosets were characterized by the limited oxygen index (LOI), UL-94 test and cone calorimeter. The results show the lower peak of heat release rate (pk-HRR), the higher flammability rating than that of flame retardant epoxy resin by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), hexa-phenoxyl-cyclotriphosphazene (HPCP) and their mixture cloning the ratio of group component of HAP-DOPO. The degradation route of HAP-DOPO was disclosed by thermogravimetric analysis (TGA), the real time Fourier transform infrared spectra (FTIR), thermogravimetric analysis/infrared spectrometry (TGA-FTIR), pyrolysis gas chromatography mass/spectrometry (Py-GC/MS). During combustion, HAP-DOPO continues to release the PO radicals and o-phenylphenoxyl radical during two degradation stages from 200 °C for its unstable trisubstituted methyl structure of HAP-DOPO, inhibits the chain reaction of decomposition and exerts the flame retardant effect in gas phase. The phosphazene groups link with the residual phosphate from degraded phosphaphenanthrene, which increases the crosslink density of residue, effectively promotes the formation of high-strength, high-yield and phosphorus-rich char layer. The structure of HAP-DOPO shows a remarkable flame retardant molecular structure-effect on enhancing the flame retardant efficiency on thermosets.
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Chemical stability of organic materials on service toward excitons and charge carriers is intrinsically associated with the operational stability and economics of state-of-the-art organic ...light-emitting devices. Here we conducted comprehensive experiments and theoretical calculations to comparatively investigate the intrinsic chemical stability of organic materials, which contain typical electron-accepting moieties of sulfonyl, phosphine-oxide, and carbonyl group. The materials with a diphenylsulfonyl moiety suffered a fatal chemical instability originating from the cleavage of C–S single bond whether under UV irradiation or in electrical-stressed devices. The material with a dibenzothiophene-S,S-dioxide moiety exhibited significantly improved chemical stability because of effective shielding of the weak C–S single bond in a ring. In contrast, the commercially used carbonyl-containing compound demonstrated the highest chemical stability with negligible degradation under the same condition. Quantum chemical calculations fully supported the experimental results and suggested that the bond strength of the weak chemical bonds of the molecules would determine the intrinsic chemical stability of the organic materials in their excited and charged states, which might be a plausible origin of the limited stability of high-energy blue-emitting materials and devices. Several implications have been drawn for the design of new blue-emitting materials.
Materials with thermally activated delayed fluorescence (TADF) realized 100% internal quantum efficiency (IQE) but suffered significant efficiency roll-off. Here, an exciton dynamics study reveals ...that materials with TADF may play opposite roles in affecting the efficiency roll-off: decreasing the triplet density due to the fast reverse intersystem crossing, on the one hand, and increasing the triplet density due to the weakened singlet radiation. We show theoretically and experimentally that TADF-sensitized phosphorescence can break this trade-off by exploiting the efficient Förster energy transfer and simultaneously achieve 100% IQE and low efficiency roll-off (with a critical current density of 460 mA cm–2).
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