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Spirocyclic hexadienones with multiple stereogenic centers are frequently found in natural products but remain challenging targets to synthesize. Herein, we report the enantioselective desymmetrization of bisphenol derivatives via Ir-catalyzed allylic dearomatization reactions, affording spirocyclic hexadienone derivatives with up to three contiguous stereogenic centers in good yields (up to 90%) and excellent enantioselectivity (up to 99% ee). The high efficiency of this reaction is exemplified by the short reaction time (30 min), low catalyst loading (down to 0.2 mol %), and ability to perform the reaction on a gram-scale. The total syntheses of (+)-tatanan B and (+)-tatanan C were also realized using this Ir-catalyzed allylic dearomatization reaction as a key step.

Airports have taken centre stage in the fight against the ongoing COVID-19 pandemic, and adoption of technologies has been instrumental in helping airport operators to mitigate operational and health concerns relating to the pandemic. A novel framework for the adoption of Industry 4.0 technologies was developed based on the insights gathered from an industry survey of 102 airport operators and managers around the world and 17 semi-structured interviews. The framework provides a ‘three-proof’ approach (proof of technology, proof of operations and proof of business) to guide airport operators in their decision-making process in adopting Industry 4.0 technologies in airports. This framework is further verified through a case study of the technology implementation efforts of a leading Asian airport.

An enantioselective chemical synthesis of arene cis-dihydrodiols has been realized from 2-pyrones through sequential ytterbium-catalyzed asymmetric inverse-electron-demand Diels-Alder (IEDDA) reaction of 2-pyrones and retro-Diels-Alder extrusion of CO2 . By using this strategy, a series of substituted arene cis-dihydrodiols can be obtained efficiently with high enantioselectivity (>99 % ee in many cases). Based on this strategy, efficient and concise asymmetric total syntheses of (+)-MK7607 and 1-epi-(+)-MK7607 were accomplished.

The LAH4 family of amphipathic peptides exhibits pronounced antimicrobial, cell penetrating and nucleic acid transfection activities. Furthermore, variants were designed with potent lentiviral transduction enhancement. When viewed along a helical wheel the four histidines are arranged to form an amphipathic structure. In order to optimize some of these biological activities the number of leucine and alanine residues exposed to the hydrophilic surface was systematically varied which resulted in the design of vectofusin a peptide with strong lentiviral transduction enhancement activities. Here the series of peptides with varying numbers of alanine or leucine residues, respectively, framed by the histidines was tested for their calcein release activity. Interestingly, the membrane pore formation and DNA transfection activities show a clear correlation with the hydrophilic angle. In contrast the membrane partitioning and the propensity to adopt helical conformations was hardly affected as long as the hydrophilic angle did not exceed a limiting value of 150°.

In order to improve the detection of similar chunks of de-duplication technology, a value evaluation model for chunks is built. On account of the locality characteristic of chunks, a strate...

Cyclone separators are considered one of the most common and widely used method of separating solid particles from fluids. The focus of this paper was to design a separator that could effectively improve the air quality of an industrial working environment by considering factors such as the nature of the particles and the restrictions on the device such as size and operating condition. To do so, a sample of the dust sample was studied to determine the characteristics of the aluminum dust. An initial separator model which satisfied the separation condition was developed, and a second model was developed with the goal of optimizing and reducing the overall size of the separator. All models developed were subjected to CFD simulations to analyze the flow patterns, separation rate at various particle diameters as well as comparing against the theoretical predicted values. The simulation results showed how the change in various parameters improved the separation efficiency. The total height of the model was approximately 20% smaller than the initial proposed design to fit into the manufacturer’s workbench while the separation efficiencies improved by an average of 5% to 10% across various particle sizes. The results obtained indicated that the efficiency of the particle collection is dependent on the area of the barrel inlet of the separator and the depth of the vortex finder.

A novel gadolinium diethylenetriamine-N, N-bis (2-acetamide benzoic acid)-N, N-bisacetic acid complex has been synthesized and characterized by elemental analysis, infrared spectrum, ultraviolet spectroscopy and thermal analysis. The interaction between Gd3+and aminopolycarboxlicacid ligand was investigated by fluorescence titration. The binding constant of this complex is calculated to be 1.2018×104L·mol-1, and binding stoichiometry is 1:1. Fluorescence spectra was also used to study the interaction between Gd (III) complex and bovine serum album (BSA). The results showed that Gd (III) complex can effectively quench the intrinsic fluorescence of BSA via static quenching. According to Stern-Volmer equation and Linewerver-Burk equation, the binding constant is calculated to be 3.7491×104L·mol-1and binding site is about 1.0.