Novel High-Speed 3D Printing Method Using Selective Oil Sintering with Thermoplastic Polyurethane Powder Printing.

Present methods used in three-dimensional (3D) printing, such as selective laser sintering (SLS) and multijet fusion (MJF), have limited applications, especially in relation to the manufacturing of biomedical products. The speed of SLS printing is too low, and high-speed 3D printing technology with MJF uses carbon black particles as a fusing agent, which cannot be removed from the completed 3D printed products. Carbon black and high-energy lasers are not suitable for biomedical applications, especially human implants. A new high-speed 3D method is therefore required. In this study, we used hot oil droplets (175°C) as a new type of fusing agent to melt the biomaterial thermoplastic polyurethane (TPU) powder particles to define the print area. This method replaces lasers and the carbon black fusing agent in high-speed 3D printing technology and is more energy efficient. In addition, this method can be used to not only print on TPU, but also on other flexible materials.

PAA/ZnO Raspberry-Shaped Composite Microspheres Decorated with Ag Nanoparticles as Cleanable SERS Substrates.

A PAA/ZnO/Ag heterostructure composite material was prepared by a reduction method. The properties of composite particles are analyzed by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), UV-visible spectroscopy, and Raman spectroscopy. Ag nanoparticles play an important role in PAA/ZnO/Ag composite microspheres, conferring new SERS properties and functions to PAA/ZnO/Ag. The intensity of the SERS signal of PAA/ZnO/Ag irradiated with UV light decreased from 10 000 to below 500. The SERS detection limit of R6G obtained was reduced to 1 × 10-6 M. The PAA/ZnO/Ag composite particles show a very good degradation effect on R6G under UV light irradiation. This study has developed a new synthesis method to prepare SERS signal enhancement materials with self-cleaning effects. According to the experimental results, the PAA/ZnO/Ag composite material has higher sensitivity than the PAA/ZnO composite material.

Disulfiram can inhibit MERS and SARS coronavirus papain-like proteases via different modes.

Severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in southern China in late 2002 and caused a global outbreak with a fatality rate around 10% in 2003. Ten years later, a second highly pathogenic human CoV, MERS-CoV, emerged in the Middle East and has spread to other countries in Europe, North Africa, North America and Asia. As of November 2017, MERS-CoV had infected at least 2102 people with a fatality rate of about 35% globally, and hence there is an urgent need to identify antiviral drugs that are active against MERS-CoV. Here we show that a clinically available alcohol-aversive drug, disulfiram, can inhibit the papain-like proteases (PLpros) of MERS-CoV and SARS-CoV. Our findings suggest that disulfiram acts as an allosteric inhibitor of MERS-CoV PLpro but as a competitive (or mixed) inhibitor of SARS-CoV PLpro. The phenomenon of slow-binding inhibition and the irrecoverability of enzyme activity after removing unbound disulfiram indicate covalent inactivation of SARS-CoV PLpro by disulfiram, while synergistic inhibition of MERS-CoV PLpro by disulfiram and 6-thioguanine or mycophenolic acid implies the potential for combination treatments using these three clinically available drugs.

Atomically flat and uniform relaxed III-V epitaxial films on silicon substrate for heterogeneous and hybrid integration.

The integration of III-V semiconductors on silicon (Si) substrate has been an active field of research for more than 30 years. Various approaches have been investigated, including growth of buffer layers to accommodate the lattice mismatch between the Si substrate and the III-V layer, Si- or Ge-on-insulator, epitaxial transfer methods, epitaxial lateral overgrowth, aspect-ratio-trapping techniques, and interfacial misfit array formation. However, manufacturing standards have not been met and significant levels of remaining defectivity, high cost, and complex integration schemes have hampered large scale commercial impact. Here we report on low cost, relaxed, atomically smooth, and surface undulation free lattice mismatched III-V epitaxial films grown in wide-fields of micrometer size on 300 mm Si(100) and (111) substrates. The crystallographic quality of the epitaxial film beyond a few atomic layers from the Si substrate is accomplished by formation of an interfacial misfit array. This development may enable future platforms of integrated low-power logic, power amplifiers, voltage controllers, and optoelectronics components.