With the development of modern nanotechnology, the application range of BaTiO3 (BT) materials has been expanded, and the design and synthesis of micro-nano scale BT materials have become one of the hot spots. In this study, ultra-small BaTiO3 (Ultra-BT) were prepared by solvothermal-calcination reaction. First, the BT precursor was prepared by solvothermal reaction with ethylene glycol as solvent, and then the BT precursor was calcined to obtain Ultra-BT. The Ultra-BT at this time is composed of uniform [010]-crystal-axis-oriented BT nanocrystals with a size of about 28 nm. The formation mechanism of Ultra-BT was revealed, namely the dissolution-deposition reaction. Ultra-BT are more favorable for the preparation of BT ceramics with uniform grain because of their ultra-small size. At a sintering temperature of 1220 degrees C, the dielectric constant of BT ceramics at the Curie temperature is 8661. This dielectric constant value is higher than that reported for BT ceramics in most literature, and even higher than some doped modified BT ceramics. The solvothermal-calcination method used for preparing Ultra-BT provides important reference value for the preparation of other ultra-small perovskite materials. At the same time, because of the excellent dielectric properties and good catalytic properties of Ultra-BT, it has potential application value in the field of dielectric and catalysis.

Multiple heteroatom doping is one of the effective strategies to tune the structure of carbon supports and enhance the catalytic performance of nanozymes. Herein, the carbon-based copper nanozyme with sulfur/nitrogen codoping (S/Cu-NC) was synthesized by one-step pyrolysis of Cu-doped ZIF-8 with thiourea encapsulated (Th/ Cu@ZIF-8). Benefiting from the synergy of binary heteroatoms and 3D porous structure, the obtained S/Cu-NC had more active sites and exhibited outstanding peroxidase-like activity. Subsequently, a dual-channel (colorimetric/fluorescent) detection method for melatonin was developed by selecting 3,3,5,5-tetramethylbenzidine (TMB) and thiamine as the substrates of S/Cu-NC, which was based on the free radical scavenging effect of melatonin. Furthermore, a simple and portable paper-based device was designed to realize the rapid detection of melatonin through color changes under ultraviolet light and daylight, and the limit of detection were 0.87 mu M and 1.42 mu M, respectively. This paper-based device was successfully applied to detect melatonin in two kinds of drug samples with satisfactory results.

Herein, we synthesized a novel N-doped carbon layer encapsulated Fe/Co bimetallic nanoparticles (Fe/Co-NC), which exhibited superior oxidase-like activity due to the facilitation of electron penetration and the formation of metal-nitrogen active sites. Fe/Co-NC could catalyze the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) to blue oxTMB. Acetylcholinesterase (AChE) could catalyze the hydrolysis of thioacetylcholine to produce reducing thiocholine, which prevented TMB from oxidation. Thus, a portable hydrogel colorimetric sensor was developed for on-site and visual monitoring of AChE with the detection limit of 0.36 U L-1, and successfully applied to detect AChE in human erythrocyte samples. Furthermore, this platform was used to investigate the inhibition of triazophos on AChE activity.

Zinc is one of the most important trace elements and deficiency can lead to significant clinical complications. Microbial transformation is one of the most important methods used to supplement organic zinc and there may be some naturally occurring microorganisms that have both higher zinc tolerances and transformation capabilities. In this study, microorganisms which displayed such characteristics were widely screened, and a strain designated T-A was found. Morphological and molecular determination demonstrated that T-A is closely related to Candida tropicalis with 87% of 18S rDNA homology, with a G+C content measured by RP-HPLC of 88.42%. Candida tropicalis sp. T-A strains were shown to grow and transform zinc best at pH5 in medium with a zinc ion concentration of 8000 μg/mL at 28 °C for 121 hours. Our results showed C. tropicalis sp. T-A’s zinc content was 19.153 mg/g dry weight, with a relative bioavailability in rats of 173% when compared with traditional zinc supplements. Our study suggests that C. tropicalis sp. T-A could be exploited for use as a potential zinc supplement.

Endophytes may depend on degrading the plant cell wall with cellulases for their survival. Therefore, cellulase produced by endophytes may be useful in releasing the active ingredient of medicinal plants.Scutellaria baicalensisGeorgi is a traditional Chinese medicinal plant widely used in China and baicalin is one of its main active ingredients. In this study, freshS. baicalensisGeorgi was used to isolate endophytes, Congo red staining was used to screen cellulase-producing strains, and HPLC was used to determine the content of baicalin inS. baicalensisGeorgi. As a result, a highly active strain of endophyte capable of the extraction of high levels of baicalin was obtained. The strain was named HG-5 and identified asBacillussp. Scanning electron microscopy analysis confirmed that the enzyme better promotes the dissolution of plant active ingredients. After optimizing the enzyme production and extraction processes, we found that when compared with the traditional extraction method, the baicalin yield was increased 79.31% after extraction with the HG-5 enzyme. The current study provides a novel approach and method for the use of endophyte cellulase to improve the extraction of compounds from medicinal plants.