Two of the key questions to be addressed are whether and how one can turn cocoon silk into fascinating materials with different electronic and optical functions so as to fabricate the flexible ...devices. In this review, a comprehensive overview of the unique strategy of mesoscopic functionalization starting from silk fibroin (SF) materials to the fabrication of various meso flexible SF devices is presented. Notably, SF materials with novel and enhanced properties can be achieved by mesoscopically reconstructing the hierarchical structures of SF materials. This is based on rerouting the refolding process of SF molecules by meso‐nucleation templating. As‐acquired functionalized SF materials can be applied to fabricate bio‐compatible/degradable flexible/implantable meso‐optical/electronic devices of various types. Consequently, functionalized SF can be fabricated into optical elements, that is, nonlinear photonic and fluorescent components, and make it possible to construct silk meso‐electronics with high‐performance. These advances enable the applications of SF‐material based devices in the areas of physical and biochemical sensing, meso‐memristors, transistors, brain electrodes, and energy generation/storage, applicable to on‐skin long‐term monitoring of human physiological conditions, and in‐body sensing, information processing, and storage.
Owing to the mesoscopic multi‐levels of structures and the intermolecular nucleation control mechanism, a revolutionary materials strategy from mesoscopic reconstruction to the fabrication of new conceptual meso‐electronic/photonic devices based on silk fibroin materials is presented. This development turns out to be very crucial in the field of flexible electronics, optics/photonics, and biomedical/healthcare, which leads to a New Silk Road in big health and the artificial intelligence era.
-Tetrahexylporphyrin was converted to its corresponding 7,8-dihydroxychlorin using an osmium tetroxide-mediated dihydroxylation strategy. Its diol moiety was shown to be able to undergo a number of ...subsequent oxidation reactions to form a chlorin dione and porpholactone, the first
-alkylporphyrin-based porphyrinoid containing a non-pyrrolic building block. Further, the diol chlorin was shown to be susceptible to dehydration, forming the porphyrin enol that is in equilibrium with its keto-chlorin form. The
-hexylchlorin dione could be reduced and it underwent mono- and bis-methylation reactions using methyl-Grignard reagents, and trifluoromethylation using the Ruppert-Prakash reagent. The optical and spectroscopic properties of the products are discussed and contrasted to their corresponding
-aryl derivatives (where known). This contribution establishes
-tetrahexyl-7,8-dihydroxychlorins as a new and versatile class of chlorins that is susceptible to a broad range of conversions to generate functionalized chlorins and a pyrrole-modified chlorin analogue.
A novel organic/inorganic S-scheme heterostructure of TCPP/Bi12O17Cl2 is successfully constructed. Taking the advantages of the strengthened visible-light response, effective spatial disintegration ...and conservation of highly energetic photo-carriers, this photosystem demonstrates a significant reinforcement of the photo-activity and stability towards the removal of antibiotics.
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•An S-scheme heterojunction of organic/inorganic TCPP/Bi12O17Cl2 was designed.•Effective spatial disintegration of powerful photo-carriers and optimized solar harvesting were achieved.•Remarkably reinforced photocatalytic performance was attained.•The tetracycline degradation pathway and the bio-toxicity of intermediates were unclosed.
The exploration of environment-friendly and efficacious materials with eminent photocatalytic efficacy is critical for the elimination of pharmaceutical antibiotics. Herein, a visible-light-driven organic–inorganic S-scheme heterostructure of meso-tetra (4-carboxyphenyl) porphyrin (TCPP)/Bi12O17Cl2, aiming to wipe out the antibiotic in wastewater, is developed via a simple approach. The TCPP is anchored on the surface of Bi12O17Cl2 to create the S-scheme junction between TCPP and Bi12O17Cl2, which strengthens visible-light response and expedites the spatial disintegration and conservation of photo-carriers with high redox capacity, therefore leading to a significant reinforcement of the photo-activity and stability. The champion TCPP/Bi12O17Cl2 manifests the best photo-degradation efficiency of 79.4% with the photoreaction rate constant of 0.0125 min−1 for tetracycline elimination, being 2.6 folds that of Bi12O17Cl2. The involved crucial reactive radicals, photo-degradation pathway and mechanism, and the eco-toxicity of intermediates over TCPP/Bi12O17Cl2 were elucidated through scavenging tests, LC-MS analysis, and toxicity calculation. This research illustrates the potential practicability on the rational design of porphyrin-based S-scheme heterojunction photocatalysts for efficient antibiotic removal.
This review presents a strategy for obtaining various functional derivatives of tetrapyrrole compounds based on transformations of unsaturated carbon-oxygen and carbon-carbon bonds of the ...substituents at the
position (
-formyl, vinyl, and ethynyl porphyrins). First, synthetic approaches to the preparation of these precursors are described. Then diverse pathways for the transformations of the multipotent synthons are discussed, revealing a variety of products of such reactions. The structures, electronic, and optical properties of the compounds obtained by the methods under consideration are analyzed. In addition, there is an overview of the applications of the products obtained. Biomedical use of the compounds is among the most important. Finally, the advantages of using the reviewed synthetic strategy to obtain dyes with targeted properties are highlighted.
•Workforce research is neglected in the top 8 T&H journals, rated by Impact Factor.•The term ‘workforce’ unifies the multiple levels at which research is conducted.•T&H workforce research is ...disjointed in topics, analysis, theory and method.•Tourism vs. hospitality research gives different treatment to workforce issues.•A multi-level model presents a contextual framework for future workforce research.
This paper offers a critical review, purview and future view of ‘workforce’ research. We argue that the tourism (and hospitality) workforce research domain, beyond being neglected relative to its importance, suffers from piecemeal approaches at topic, analytical, theoretical and methods levels. We adopt a three-tiered macro, meso and micro level framework into which we map the five pervasive themes from our systematic review across a 10year period (2005–2014). A critique of the literature, following a ‘representations’ narrative, culminates in the development of a tourism workforce taxonomy, which we propose should provide the starting point for a pathway to guide the advancement of a more holistic approach to tourism workforce knowledge development.
Novel boron‐dipyrromethene (BODIPY)‐bridged 22‐oxacorrole dyads, using meso‐pyrrolyl 22‐oxacorrole as a key synthon, have been synthesized. The reactivity of the meso‐pyrrolyl group of 22‐oxacorrole ...was exploited to synthesize the first examples of BODIPY‐bridged 22‐oxacorrole dyads in ≈40 % yield. The dyads are stable and exhibited interesting spectral and electrochemical properties.
BODIPY selecta! A class of novel BODIPY‐bridged 22‐oxacorrole dyads have been synthesized by exploiting the reactivity of the meso‐pyrrole group of meso‐pyrrolyl meso‐free 22‐oxacorrole (see scheme; ET=energy transfer).
To capture the uniaxial compression fracture of concrete composite is still a great challenging problem. To this end, the newly proposed nonlocal macro–meso-scale consistent damage (NMMD) model is ...extended to simulate uniaxial compression fracture of concrete composites. In the NMMD model, a mesoscopic structure composed of material point pairs is attached to each material point. A decomposition scheme suitable for masonry-like materials is adopted to decompose the elongation quantity of point pairs. The topologic damage is defined as the weighted summation of mesoscopic damage in neighboring material point pairs driven by the decomposed elongation quantity. The physically-based energetic degradation function is employed to bridge the geometric discontinuity in solids and the energy dissipation, and thus the topologic damage is integrated into the framework of continuum damage mechanics. The Monte-Carlo method and two-phase random field model are employed to generate stochastic circular and irregular aggregates representing the meso structure of concrete, respectively. The interface transition zone is prescribed by reducing the critical value of interface point pairs. Numerical results indicate that both the crack patterns and stress–strain curves of the uniaxial compression experiments on concrete panels can be well captured by the proposed NMMD model without mesh size sensitivity. The influence of horizontal constraints on the top and bottom surfaces is investigated and shown to have an effect on the crack patterns, strength and deformation capability of the specimen. The necessity of decomposition is also illustrated.
•The NMMD model is extended to compressive failure simulation of concrete composite.•Both the crack patterns and stress–strain curves can be captured by the NMMD model objectively.•The influence of horizontal constraints is investigated.•The necessity of damage driving force decomposition is illustrated.
Raman spectrum of the meso tetraphenylporphine (TPP) deposited onto smooth copper surface as thin film were recorded in the region 200–1700cm−1. To investigate the effect of meso-phenyl substitution ...rings on the vibrational spectrum of free base porphyrin, we calculated Raman and infrared (IR) spectra of the meso-tetraphenylporphine (TPP), meso tetramethylporphine (TMP), copper (II)porphine (CuPr) and free base porphine (FBP) at the B3LYP/6-311+G(d,p) level of the density functional theory (DFT). The observed Raman spectrum of the TPP is assigned based on the calculated its Raman spectrum in connection with the calculated spectra of the TMP, CuPr and FBP by taking into account of their corresponding vibrational motions of the Raman modes of frequencies. Results of the calculations clearly indicated that the meso tetraphenyl substitution rings are totally responsible for the observed Raman bands at ∼1593, 1234 and 1002cm−1. The calculated and observed Raman spectra also suggested that the observed Raman band with a medium intense at 962cm−1 might result from the surface plasmon effect. Furthermore, the observed Raman bands with medium intense at ∼334 and ∼201cm−1 are as results of the dimerization or aggregation of the TPP or would be that related to intramolecular interaction. We also calculated IR spectra of these molecules at same level of the theory. To investigate the solvent effect on the vibrational spectrum of porphine, the Raman and IR spectra of the TPP and FBP are calculated in solution phase where water used as solvent. The results of these calculation indicated that there is no any significant effect on the vibrational spectrum of the TPP.
•The novel polyester loose nanofiltration membranes were fabricated by interfacial polymerization method.•The optimized polyester membrane exhibited excellent water permeability.•This polyester ...membrane exhibited both a high rejection of dyes and a high transmission of salts.•This polyester membrane showed a superior antifouling performance and long-term stability.
Loose nanofiltration membranes with a remarkable water permeability are highly promising for the fractionation of dyes and salts in the treatment of textile wastewater. In this study, a novel polyester membrane with unprecedented water permeability was developed via interfacial polymerization (IP), in which meso-erythritol (ME) was utilized as an aqueous monomer. Instead of using toxic catalysts, sodium hydroxide was incorporated to the aqueous solution to catalyze the ester reaction between hydroxyl and acyl chloride. A series of characterizations demonstrated that the formed polyester film is hydrophilic and negatively charged, with microsphere structures on the surface. Due to the low-active hydroxyl groups of the aqueous monomers, the participation of ME could yield a coherent polyester film with slightly loose structure atop the polyethersulfone (PES) membrane. The resultant membrane with high water permeability exhibited both a high rejection of dyes and a high transmission of salts. The rejection of the LNFM-2 membrane with an excellent water permeability of 53.23 LMH bar−1 for Congo red (CR), direct red 23 (DR23), reactive blue 2 (RB2), Na2SO4, NaCl was 99.6%, 95.2%, 99.6%, 11.0%, and 5.6% respectively. Furthermore, LNFM-1 has a water permeability of up to 87.13 LMH bar−1 while maintaining a competitive dye/salt separation performance. In addition, this type of polyester membrane has a superior antifouling performance and long-term stability during the filtration of dye/salt mixtures.
The newly developed polyester LNF membranes have great application potential in the treatment of textile wastewater. This study paves the way for applying hydroxyl monomers like polyols for constructing TFC membranes for diverse separations.
Unprecedented enantioselectivity and catalytic activity was observed in the asymmetric copolymerization of CO2 with meso‐epoxides (including the less reactive cyclopentene oxide) mediated by the ...dinuclear CoIII complex (S,S,S,S)‐1 under mild conditions. The resultant copolymers possess more than 99 % carbonate linkages and a perfectly isotactic structure.
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