Suppressing Non-Radiative Relaxation through Single-Atom Metal Modification for Enhanced Fluorescence Efficiency in Molybdenum Disulfide Quantum Dots.

To enhance the fluorescence efficiency of semiconductor nanocrystal quantum dots (QDs), strategies via enhancing photo-absorption and eliminating non-radiative relaxation have been proposed. In this study, we demonstrate that fluorescence efficiency of molybdenum disulfide quantum dots (MoS2 QDs) can be enhanced by single-atom metal (Au, Ag, Pt, Cu) modification. Four-fold enhancement of the fluorescence emission of MoS2 QDs is observed with single-atom Au modification. The underlying mechanism is ascribed to the passivation of non-radiative surface states owing to the new defect energy level of Au in the forbidden band that can trap excess electrons in n-type MoS2 , increasing the recombination probability of conduction band electrons with valence band holes of MoS2 . Our results open an avenue for enhancing the fluorescence efficiency of QDs via the modification of atomically dispersed metals, and extend their scopes and potentials in a fundamental way for economic efficiency and stability of single-atom metals.

Dispersive Magnetic Solid-Phase Extraction Coupled to Direct Analysis in Real Time Mass Spectrometry for High-Throughput Analysis of Trace Environmental Contaminants.

Coupling dispersive magnetic solid-phase extraction (DMSPE) to direct analysis in real time mass spectrometry (DART-MS) with a newly developed metal iron probe enables high-throughput, sensitive detection of herbicides such as triazine in environmental waters. Magnetic graphene oxide was used as a dispersive sorbent because it increased adsorption capacity in the DMSPE process. The planar structure and excellent thermal conductivity of graphene oxide facilitated the desorption and ionization of target analytes in DART-MS analysis. The iron probe, which is designed to fit into the moving trail of the DART interface, served as the sorbent collector as well as the support for the magnetic graphene oxide after DMSPE, and was put directly into the DART system. The ratio of magnetic core to graphene oxide in the nanoparticles and other key parameters in DMSPE and DART-MS procedures were systematically investigated and optimized. In addition, the presence of water on the sorbent proves to have a significant effect on DART-MS analysis. No organic solvents are used in this method, and the reusable iron probe is of low cost. Under the optimal conditions, limits of detection were found in the range of 1.6-152.1 ng/L for the triazines. Recovery and reproducibility were found to be in the ranges of 87.5-115.0% and 1.9-10.2%, respectively, for the six herbicides studied. The analytical performance of the DMSPE-DART-MS method indicated that applications for trace analysis of other compounds in liquid samples are also possible.

Photoenhanced Electrocatalytic Hydrogen Evolution Accelerated Dominantly by the Hot Electrons from Intraband Transition rather than Interband Transition.

Plasmonic materials enabling sunlight as an energy input to catalyze the hydrogen evolution reaction (HER) have become the research focus of artificial photosynthesis. Upon visible photoexcitation, there are both intraband transition and interband transition hot carriers generated, and which of them dominates the catalytic reaction remains elusive. Here, the contributions of hot electrons from intraband and interband transitions to the photoelectrocatalytic HER on plasmonic Au triangle nanoprisms (AuTNPs) have been studied. Compared with the dark reaction, the exchange current density increases by 9-fold and 3-fold under intraband and interband excitation, respectively, which is attributed to the higher energy level of intraband transition hot electrons. By calculation of the reaction activation energy with and without illumination, the contributions of the hot electrons from the two photoexcitation modes to the photoenhanced electroreduction reaction (PEER) are quantitatively analyzed, proposing the general standard to measure the effect of different hot electrons in different reactions.

Clostridium butyricum improves the intestinal health of goats by regulating the intestinal microbial community.

Clostridium butyricum, as a probiotic with a variety of active products, has been widely used to improve the intestinal health of humans and animals. Previous studies had demonstrated that Clostridium butyricum exhibited potential protective and positive effects in human disease research and animal production by producing a variety of beneficial substances, such as intestinal inflammation, the intestinal epithelial barrier, metabolic diseases, and regulation of the gut microbiota. Therefore, we hypothesized that dietary Clostridium butyricum supplementation could improve gut health in fattening goats by modulating gut microbiota. However, it is unclear whether Clostridium butyricum can reach the intestine through the rumen, so 15 healthy Albas goats were selected and randomly divided into 3 treatments with 5 replicates in each group. The groups were divided as follows: control group (CON: basal diet), rumen-protected Clostridium butyricum group (RPCB: basal diet plus 1.0 × 109 CFU/kg Clostridium butyricum coated with hydrogenated fat), and Clostridium butyricum group (CB: basal diet plus 1.0 × 109 CFU/kg Clostridium butyricum). The experiment was slaughtered after a 70-day growth test, and the jejunal mucosa and intestinal contents of the goats were collected to determine tight junction proteins related genes expression and 16S rDNA microbial sequencing analysis to evaluate the intestine health. The results showed that dietary supplementation with Clostridium butyricum significantly increased the expression of the Claudin-4 gene of the jejunal mucosa (P < 0.05) and had a trend toward a significant increase in the Occludin gene (0.05 < P < 0.10). However, Clostridium butyricum had no significant effect on the expression of intestinal inflammatory factors (P > 0.10). In addition, the relative fractionation of Clostridium and Clostridiaceae_unclassified in the gut microbiota at the genus level decreased significantly compared with controls (P < 0.05). The results of the analysis of the level of Clostridium species showed that Clostridium butyricum only existed in the treatment group. And the correlation results showed that Occludin and Claudin-4 genes were positively correlated with Sharppea and Clostridium butyricum, and negatively correlated with Clostridium (P < 0.05). Supplementing Clostridium butyricum in the diet did not significantly affect the intestinal immune function of goats, while regulation of the intestinal microbiota was associated with improving the intestinal epithelial barrier.

Spatiotemporally Actuated Hydrogel by Magnetic Swarm Nanorobotics.

Magnetic nanorobotic swarms can mimic collective functions of organisms in nature and be programmed for flexible spatiotemporal control. In this work, different assemblies of magnetic nanoparticle (MNP) swarms were constructed. Temperature-sensitive hydrogels were used as carriers to fix the distribution and ensure the stability of the swarm structure and the biocompatibility of the microrobot. Under three different outfield assembly strategies (gravitational field, gradient magnetic field, and uniform magnetic field), six different assembly modes of MNP are encapsulated (three unilateral unfolding assemblies with different microsphere profiles, unilateral chain assembly, and two symmetric chain assemblies with different magnetic chain positions). Their differences in the execution of motion, magnetothermal effects, and release of loaded DOX drugs were explored. The results showed that the symmetrical chain assembly with the magnetic chain distributed on the outside showed the best performance due to the advantage of the magnetic moment. It has a speed of up to 600 µm/s and a temperature rise rate of up to 1.5 °C/min. The present work provides an excellent solution to the poor MNP cluster distribution stability problem and enriches the assembly control scheme of microrobots in medical, catalytic, and three-dimensional-printing fields.

Mechanism of Chaihu Shugan Powder () for Treating Depression Based on Network Pharmacology.

OBJECTIVE: To analyze the effective components of Chinese medicine (CM) contained in Chaihu Shugan Powder (, CSP) in the treatment of depressive disorders and to predict its anti-depressant mechanism by network pharmacology. METHODS: Absorption, distribution, metabolism, excretion, and toxicity calculation method was used to screen the active components of CSP. Traditional Chinese Medicine System Pharmacological Database Analysis Platform and text mining tool (GoPuMed database) were used to predict and screen the active ingredients of CSP and anti-depressive targets. Through Genetic Association Database, Therapeutic Target Database, and PharmGkb database targets for depression were obtained. Cytoscape3.2.1 software was used to establish a network map of the active ingredients-targets of CSP, and to analyze gene function and metabolic pathways through Database for Annotation, Visualization and Integrated Discovery and the Omicshare database. RESULTS: The 121 active ingredients and 15 depression-related targets which were screened from the database can exert antidepressant effects by improving the neural plasticity, growth, transfer condition and gene expression of neuronal cell, and the raise of the expression of gap junction protein. The 15 targets passed 14 metabolic pathways, mainly involved in the regulation of neurotransmitters (5-hydroxytryptamine, dopamine and epinephrine), inflammatory mediator regulation of TRP channels, calcium signaling pathway, cyclic adenosine monophosphate signaling pathway and neuroactive ligand-receptor interaction and other signal channels to exert anti-depressant effects. CONCLUSION: This article reveals the possible mechanism of CSP in the treatment of depression through network pharmacology research, and lays a foundation for further target studies.

Application of ultrasound counter currentextraction in patent of traditional Chinese medicine / 中国中药杂志

The patent information of ultrasound countercurrent extraction used in traditional Chinese medicine was analyzed in this paper by the samples from Derwent World Patent Database (DWPI) and the Chinese Patent Abstracts Database (CNABS). The application of ultrasound countercurrent was discussed with the patent applicant,the amount of the annual distribution, and the pharmaceutical raw materials and other aspects. While the technical parameters published in the patent was deeply analyzed, such as material crushing, extraction solvent, extraction time and temperature, extraction equipment and ultrasonic frequency. Thought above research, various technical parameters of ultrasound countercurrent extraction used in traditional Chinese was summarize. The analysis conclusion of the paper can be used in discovering the technical advantages, optimizing extraction conditions, and providing a reference to extraction technological innovation of traditional Chinese medicine.