In-situ tailored strategy to remove capping agents from copper sulfide for building better lithium-sulfur batteries

Capping agents are frequently used in the chemical synthesis of materials to precisely tailor the size, shape, and composition with the high-performance catalysis expectation. However, as two sides of a...

The effect of microwave irradiation on the synthesis of hydroxyapatite/biopolymer nanocomposites

Microwave irradiation (MWI) in the synthesis of materials has been an actively developing branch of science for the last three decades. Structures based on calcium phosphates (CaP) are one of the most well-known and widely used synthetic biomaterials in orthopedics and dentistry. The main topic of this review is the use of MWI in the formation of biomaterials based on calcium phosphate phases and their complexes with biopolymers (chitosan, alginate, silk fibroin). The physical bases of MW interaction with different materials are considered, including the influence of this irradiation on the structure, physicochemical and mechanical properties of biomaterials (crystallite size, porosity, strength, capability to absorb and release drugs). The main heating mechanisms during MWI are described, namely: the dipolar losses, and losses of conductivity. Important advantages of MWI treatment are reducing processing time, reducing electricity use, reducing waste and improving quality of the synthesized biomaterials. A list and comparison is made of articles describing the production of HA crystals with different morphology (nanowires, spherical, needle- and rod-shaped) with all the initial conditions and their effect on the synthesized material. The latest developments in the field of biomaterials conducted based on the laboratory “Bionanocomposite” of Sumy State University are considered. The original synthesis method of CaP-biopolymer materials is described, as well as the advantages of the synthesized scaffolds over foreign developments. It is expected that this review of the interdisciplinary topic will contribute to the further study of other new applications of microwave technologies in the synthesis of the latest modern biomaterials created by scientists, biomedical engineers in other laboratories and institutions in Ukraine and around the world.

Ultrasound for Material Characterization and Processing

Ultrasonic waves are nowadays used for multiple purposes in many different fields from the non-destructive inspection of materials to sonochemical synthesis of materials and welding [...]

Approaches to Simulation of Interaction of Concentrated Solar Radiation with Materials

The paper analyzes approaches to modeling the processes of interaction of concentrated solar radiation with materials. The experimental results obtained on the synthesis of materials from a melt in a solar furnace are presented. It is shown that when melting in a solar furnace under the influence of concentrated solar radiation of high density due to the acceleration of the recovery process, it is possible to obtain a fine-grained microstructure that gives the material enhanced mechanical and dielectric properties. It is shown that the relationship between the structure and properties of the materials obtained with the technological parameters of melting and cooling in a solar furnace can be used as an approach to modeling the interaction of concentrated solar radiation with materials

Modification of an Engineered Escherichia Coli by a Combinatorial Strategy to Improve 3,4-Dihydroxybutyric Acid Production

Objectives: 3,4-Dihydroxybutyric acid (3,4-DHBA) is a multi-functional C4 platform compound with wide applications in the synthesis of materials and pharmaceuticals. Currently, although the biosynthetic pathway for the production of 3,4-DHBA has been developed, low productivity still hampers its use on large scales. Here, a non-natural four-steps biosynthetic pathway was established in recombinant E. coli with a combinatorial strategy.Results: Firstly, several aldehyde dehydrogenases (ALDHs) were screened and characterized for catalyzing the dehydrogenation of 3,4-dihydroxybutanal (3,4-DHB) to 3,4-DHBA through in vitro enzyme assays. Secondly, a recombinant E. coli was successfully constructed to generate 3,4-DHBA from D-xylose by introducing the pathway containing BsGDH, YagF, PpMdlC and ALDH into E. coli with 3.04 g/L 3,4-DHBA obtained. Then, disruption of competing pathways by deleting xylA, ghrA, ghrB and adhP genes contributed to increase the accumulation of 3,4-DHBA by 87%. Final, fusion expression of PpMdlC and YagF resulted in an enhancement of 3,4-DHBA titer (7.71 g/L), as the highest titer reported so far.Conclusions: These results showed that deleting competing pathways and constructing fusion protein could significantly improve the 3,4-DHBA titer in engineered E. coli.

Structural, Morphological and Elemental Analysis of Selectively Etched and Exfoliated Ti3AlC2 MAX Phase

In the present research major focus is on the synthesis of materials that can be easily used in small portable devices and as energy storage devices. Here we focused on a new family of 2D materials Ti3C2 (MXenes). Ti3AlC2 (MAX phase) was intercalated using selective etching of Aluminium present in the MAX phase. The etching was done using HF in combination with HCl followed by delaminated in DMSO medium using ultrasonication. The synthesized samples were physically characterized via XRD, SEM and EDX. The XRD spectra confirms the formation of MXene through its characteristic plane (002) arising at 2θ~9°. The morphological study revealed the stacked layered sheet like structure obtained through SEM. The elemental confirmation of removal of Al was done using EDX spectroscopy.