Heterophase Intermetallic Compounds for Electrocatalytic Hydrogen Production at Industrial-Scale Current Densities.

Heterophase nanomaterials have sparked significant research interest in catalysis due to their distinctive properties arising from synergistic effects of different components and the formed phase boundary. However, challenges persist in the controlled synthesis of heterophase intermetallic compounds (IMCs), primarily due to the lattice mismatch of distinct crystal phases and the difficulty in achieving precise control of the phase transitions. Herein, orthorhombic/cubic Ru2Ge3/RuGe IMCs with engineered boundary architecture are synthesized and anchored on the reduced graphene oxide. The Ru2Ge3/RuGe IMCs exhibit excellent hydrogen evolution reaction (HER) performance with a high current density of 1000 mA cm-2 at a low overpotential of 135 mV. The presence of phase boundaries enhances charge transfer and improves the kinetics of water dissociation while optimizing the processes of hydrogen adsorption/desorption, thus boosting the HER performance. Moreover, an anion exchange membrane electrolyzer is constructed using Ru2Ge3/RuGe as the cathode electrocatalyst, which achieves a current density of 1000 mA cm-2 at a low voltage of 1.73 V, and the activity remains virtually undiminished over 500 h.

Breaking Highly Ordered PtPbBi Intermetallic with Disordered Amorphous Phase for Boosting Electrocatalytic Hydrogen Evolution and Alcohol Oxidation.

Constructing amorphous/intermetallic (A/IMC) heterophase structures by breaking the highly ordered IMC phase with disordered amorphous phase is an effective way to improve the electrocatalytic performance of noble metal-based IMC electrocatalysts because of the optimized electronic structure and abundant heterophase boundaries as active sites. In this study, we report the synthesis of ultrathin A/IMC PtPbBi nanosheets (NSs) for boosting hydrogen evolution reaction (HER) and alcohol oxidation reactions. The resulting A/IMC PtPbBi NSs exhibit a remarkably low overpotential of only 25 mV at 10 mA cm-2 for the HER in an acidic electrolyte, together with outstanding stability for 100 h. In addition, the PtPbBi NSs show high mass activities for methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR), which are 13.2 and 14.5 times higher than those of commercial Pt/C, respectively. Density functional theory calculations demonstrate that the synergistic effect of amorphous/intermetallic components and multimetallic composition facilitate the electron transfer from the catalyst to key intermediates, thus improving the catalytic activity of MOR. This work establishes a novel pathway for the synthesis of heterophase two-dimensional nanomaterials with high electrocatalytic performance across a wide range of electrochemical applications.

OTUD7B knockdown inhibits the proliferation and stemness of breast cancer cells by destabilizing FOXM1.

Breast cancer is a leading cause of cancer-related death in women worldwide; therefore, there is an urgent need to develop novel therapies and drugs that prolong the survival and improve the quality of life of patients with breast cancer. In the present study, the effects and underlying mechanisms of OTU domain-containing 7B (OTUD7B) knockdown on breast cancer were investigated using MDA-MB-468, MDA-MB-453 and MCF7 cell lines. The results of Cell Counting Kit 8, colony formation and tumor sphere formation experiments showed that OTUD7B knockdown caused a significant decrease in the proliferation and sphere formation ability of MDA-MB-468, MDA-MB-453 and MCF7 cells in vitro. Moreover, western blotting results showed that CD44, EpCAM, SOX2 and Nanog protein levels were significantly decreased following OTUD7B knockdown. These findings indicated that OTUD7B knockdown reduced the proliferation and stemness of breast cancer cells. Co-immunoprecipitation assays demonstrated that OTUD7B interacted with forkhead box protein M1 (FOXM1) and reduced the polyubiquitylation of FOXM1 in breast cancer cells; accordingly, FOXM1 protein levels were significantly decreased by OTUD7B knockdown. Furthermore, the overexpression of FOXM1 reduced the inhibitory effects of OTUD7B knockdown on breast cancer cells. The findings of the present study provide new insights into the oncogenic role of OTUD7B in breast cancer and indicate that OTUD7B may serve as a therapeutic target for breast cancer.

Bromide Ions Triggered Synthesis of Noble Metal-Based Intermetallic Nanocrystals.

Ordered intermetallic nanomaterials with a well-defined crystal structure and fixed stoichiometry facilitate the predictable control of their electronic structure and catalytic performance. To obtain the thermodynamically stable intermetallic structures, the conventional approaches with high-temperature annealing are still far from satisfactory, because of annealing-induced aggregation and sintering of nanomaterials. Herein, a general wet-chemical method is developed to synthesize a series of noble metal-based intermetallic nanocrystals, including hexagonal close-packed (hcp) PtBi nanoplates, face-centered cubic (fcc) Pd3 Pb nanocubes, and hcp Pd2.5 Bi1.5 nanoparticles. During the synthetic process, Br- ions play two important roles for the formation of ordered intermetallic structures: i) Br- ions can coordinate with the metal ions to decrease their reduction potentials thus slowing down the reduction kinetics. ii) Br- ions can combine with molecular oxygen to generate an oxidative etching effect, hence reconstructing the atom arrangement, which is beneficial for the formation of the intermetallic structure. As a proof-of-concept application, Pd3 Pb nanocubes are used as electrocatalysts for ethanol and methanol oxidation reactions, which exhibit significantly improved electrochemical performance compared with the commercial Pd black catalyst.

A novel neutral loss/product ion scan-incorporated integral approach for the untargeted characterization and comparison of the carboxyl-free ginsenosides from Panax ginseng, Panax quinquefolius, and Panax notoginseng.

Differentiated composition in precursor ions for different subclasses of ginsenosides in the negative electrospray-ionization mode has been reported, which lays a foundation for the sorted and untargeted identification of ginsenosides. Carboxyl-free ginsenosides simultaneously from Panax ginseng, P. quinquefolius, and P. notoginseng, were comprehensively characterized and statistically compared. A neutral loss/product ion scan (NL-PIS) incorporated untargeted profiling approach, coupled to ultra-high performance liquid chromatography, was developed on a linear ion-trap/Orbitrap mass spectrometer for characterizing carboxyl-free ginsenosides. It incorporated in-source fragmentation (ISF) full scan-MS1, mass tag-MS2, and product ion scan-MS3. Sixty batches of ginseng samples were analyzed by metabolomics workflows for the discovery of ginsenoside markers. Using formic acid (FA) as the additive, carboxyl-free ginsenosides (protopanaxadiol-type, protopanaxatriol-type, and octillol-type) gave predominant FA-adducts, while rich deprotonated molecules were observed for carboxyl-containing ginsenosides (oleanolic acid-type and malonylated) when source-induced dissociation (SID) was set at 0 V. Based on the NL transition [M+FA‒H]- > [M-H]- and the characteristic sapogenin product ions, a NL-PIS approach was established. It took advantage of the efficient full-information acquisition of ISF-MS1 (SID: 50 V), the high specificity of mass tag (NL: 46.0055 Da)-induced MS2 fragmentation, and the substructure fragmentation of product ion scan-MS3. We could characterize 216 carboxyl-free ginsenosides, and 21 thereof were potentially diagnostic for the species differentiation. Conclusively, sorted and untargeted characterization of the carboxyl-free ginsenosides was achieved by the established NL-PIS approach. In contrast to the conventional NL or PIS-based survey scan strategies, the high-accuracy MSn data obtained can enable more reliable identification of ginsenosides.

Photocatalytic synthesis of gold nanoparticles using TiO2 nanorods: a mechanistic investigation.

Herein, we investigate the mechanism of photocatalytic synthesis of noble metal nanoparticles by reductive photoelectrons generated from semiconductors. To slow down the reaction rate for real-time mechanistic study, oleic acid-capped TiO2 nanorods served as photocatalysts, and chloroauric acid dissolved in oleylamine acted as the gold precursor. Based on the experimental results from the in situ absorption spectrum and corresponding TEM image, we could clarify the photoreduction mechanism: the TiO2 nanorods generate electrons under UV irradiation and provide catalytic centers for the nucleation of gold nanoparticles. Subsequently, the seeded growth of Au nanoparticles is mainly assisted by TiO2 nanorods with continuous reduction of the gold precursor. Interestingly, the separation of Au nanoparticles from TiO2 nanorods could be clearly observed. This proposed reaction mechanism may provide a convenient understanding of the photocatalytic synthesis of noble metal nanoparticles by semiconductors.

Study on the herb-herb interaction of Danqi Tongmai Tablet based on the pharmacokinetics of twelve notoginsenoides in acute myocardial ischemia and sham rats.

Danqi Tongmai tablet (DQTT), an innovative TCM formula under clinical trials, is composed of salvianolic acids (SA) and panax notoginsenosides (PNE) for the treatment of coronary heart disease and angina pectoris. However, the in vivo herb-herb interaction of DQTT remains unclear. In the present research, a rapid, reliable and sensitive method for quantitative analysis of multi-notoginsenoside in rat plasma based on ultra high performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-TQ/MS) was established and then applied to explore the herb-herb interaction mechanism of DQTT based on the pharmacokinetics in acute myocardial ischemia (AMI) and sham rats after oral administration of DQTT and PNE. Compared with sham rats after oral administration of PNE, the values of AUC0-t for Rf and Rb2 were significantly higher in DQTT group. Compared with AMI rats after oral PNE, AUC0-t for NR1, Rg1, Re, Rb1, Rd, Rg2, Rb2, NR2, Rh1, F1 and F2 were significantly increased after oral administration of DQTT. These results hinted that SA could improve the bioavailability of notoginsenosides in AMI rats, which provides scientific information for better understanding the herb-herb interaction mechanism and offers a reference for clinical administration of DQTT. Additionally, the presently developed methodology was simple, robust, accurate, precise, and would be useful for the pharmacokinetic studies for all kinds of notoginsenosides and other herbal saponins.

Implementation of a Single Quadrupole Mass Spectrometer for Fingerprint Analysis: Venenum bufonis as a Case Study.

The mass spectrometry (MS) has been widely used for profiling chemical components of traditional Chinese medicine (TCM). However, there are few studies reporting quality control of TCM based on mass spectrometry fingerprint (MSF) due to its complicated operation and high cost. The aim of this study was to extend the application of MSF for quality evaluation of TCM. In this study, an MSF based on single quadrupole mass spectrometry method was established, and was successfully used for the quality control of Venenum bufonis (VB), a famous TCM which was used clinically for cancer treatment in China. The results showed that the superiority of MSF for more chemical information exposure and the finding of more potential chemical markers (eight versus four) compared with the traditional photo-diode array (a kind of ultra violet detector, PDA). Besides, the performance of MSF was also validated by similarity and principle component analysis (PCA) of MS data acquired on two other mass spectrometry (low-resolution, triple quadrupole, QQQ, and high-resolution, quadruple time-of-flight, Q-TOF), showing high consistency with QQQ and Q-TOF, but robustness with few parameters' settings. Based on our study, MSF could be widely applied for the quality control of TCM.

Rapid profiling of polymeric phenolic acids in Salvia miltiorrhiza by hybrid data-dependent/targeted multistage mass spectrometry acquisition based on expected compounds prediction and fragment ion searching.

Phenolic acids are the major water-soluble components in Salvia miltiorrhiza (>5%). According to previous studies, many of them contribute to the cardiovascular effects and antioxidant effects of S. miltiorrhiza. Polymeric phenolic acids can be considered as the tanshinol derived metabolites, e.g., dimmers, trimers, and tetramers. A strategy combined with tanshinol-based expected compounds prediction, total ion chromatogram filtering, fragment ion searching, and parent list-based multistage mass spectrometry acquisition by linear trap quadropole-orbitrap Velos mass spectrometry was proposed to rapid profile polymeric phenolic acids in S. miltiorrhiza. More than 480 potential polymeric phenolic acids could be screened out by this strategy. Based on the fragment information obtained by parent list-activated data dependent multistage mass spectrometry acquisition, 190 polymeric phenolic acids were characterized by comparing their mass information with literature data, and 18 of them were firstly detected from S. miltiorrhiza. Seven potential compounds were tentatively characterized as new polymeric phenolic acids from S. miltiorrhiza. This strategy facilitates identification of polymeric phenolic acids in complex matrix with both selectivity and sensitivity, which could be expanded for rapid discovery and identification of compounds from complex matrix.

Characteristic Chromatogram: A Method of Discriminate and Quantitative Analysis for Quality Evaluation of Uncaria Stem with Hooks.

It remains a challenge to establish new monographs for herbal drugs derived from multiple botanical sources. Specifically, the difficulty involves discriminating and quantifying these herbs with components whose levels vary markedly among different samples. Using Uncaria stem with hooks as an example, a characteristic chromatogram was proposed to discriminate its five botanical origins and to quantify its characteristic components in the chromatogram. The characteristic chromatogram with respect to the components of Uncaria stem with hooks with the five botanical origins was established using 0.02% diethylamine and acetonitrile as the mobile phase. The total analysis time was 50 min and the detection wavelength was 245 nm. Using the same chromatogram parameters, the single standard to determine multicomponents method was validated to simultaneously quantify nine indole alkaloids, including vincosamide, 3α-dihydrocadambine, isocorynoxeine, corynoxeine, isorhynchophylline, rhynchophylline, hirsuteine, hirsutine, and geissoschizine methyl ether. The results showed that only the Uncaria stem with hooks from Uncaria rhynchophylla, the most widely used in the herbal market, showed the presence of these nine alkaloids. The conversion factors were 1.27, 2.32, 0.98, 1.04, 1.00, 1.02, 1.26, 1.33, and 1.25, respectively. The limits of quantitation were lower than 700 ng/mL. The total contents of 31 batches of Uncaria stem with hooks were in the range of 0.1 - 0.6%, except for Uncaria hirsuta Havil and Uncaria sinensis (Oliv.) Havil. The results also showed that the total content of indole alkaloids tended to decrease with an increase in the hook diameter. This showed that the characteristic chromatogram is practical for controlling the quality of traditional Chinese medicines with multiple botanical origins.

Anticonvulsant and sedative-hypnotic activity screening of pearl and nacre (mother of pearl).

ETHNOPHARMACOLOGICAL RELEVANCE: Pearl and nacre are valuable traditional medicines to treat palpitations, convulsions or epilepsy in China for thousands of years. However, the active ingredients are not clear till now. AIM OF THE STUDY: The main purpose of the current investigation was to assess the anticonvulsant and sedative-hypnotic activity of pearl powder and nacre powder, including their corresponding 6 protein extracts. MATERIAL AND METHODS: Determination of the amino acid composition of the obtained protein was carried out by ultra-performance liquid chromatography (UPLC) combined with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) pre-column derivatisation. The influence of the tested drugs on locomotor activity and convulsions latency was recorded. The contents of 5-Hydroxytryptamine (5-HT) and γ-aminobutyric acid (GABA) in brain were detected by enzyme-linked immunesorbent assay (ELISA) kits. In addition, immunohistochemistry was carried out to evaluate the changes of 5-HT3 and GABAB. In parallel, the expressions of them were demonstrated by western blot. RESULTS: The obtained data suggested that pearl original powder (1.1g/kg), pearl water-soluble protein (0.2g/kg), pearl acid-soluble protein (0.275g/kg), pearl conchiolin protein (1.1g/kg), nacre original powder (1.1g/kg), nacre water-soluble protein (0.2g/kg), nacre acid-soluble protein (0.7g/kg) and nacre conchiolin protein (1.1g/kg) could down-regulate the expression of 5-HT3 and up-regulate the level of GABAB to varying degrees compared with the control group. Besides, drug administration also reduced the locomotor activity and increased convulsions latency with a certain mortality. CONCLUSIONS: These findings correlated with the traditional use of pearl and nacre as sedation and tranquilization agents, thus making them interesting sources for further drug development and also providing critical important evidence for the selection of quality control markers.

Development of specific and quantitative methods for the quality control of the polysaccharides from sea-tangle and sargassum.

Polysaccharides from numerous traditional Chinese medicines have been proven as the bioactive ingredients and are hence used as the quality control markers. However, the assessment criteria always show a poor specificity, due to the lack of systematic comparison among the analogous herbs. In the present study, two similar materials, namely sea-tangle and sargassum, were selected as the model herbs to develop more specific methods for quality control. Two well-established methods, determination of the total polysaccharides content and monosaccharides composition analysis, were both employed. Based upon the quantitative results, the evaluation criteria of the polysaccharides contents of not less than 2.0% and 1.7% were proposed for sea-tangle and sargassum, respectively. Nine identical monosaccharide derivatives appeared on the HPLC chromatograms of the hydrolysis and derivatized solutions of the two drugs. Principal component analysis and orthogonal partial least squares discriminant analysis using the peak areas of monosaccharides derivatives as the variables were performed, and the results indicated that mannuronic acid and xylose with the opposite concentrations in the two drugs were the differential components. A discriminative criterion using the peak area ratio of these two monosaccharides derivatives was proposed for the qualitative identification. In conclusion, a more specific and quantitative quality control method was developed for sea-tangle and sargassum.