[Effect of PEG400 on pharmacokinetics of baicalin and baicalein in gut microbiotadysbiosis rats].

The study aimed to establish an UPLC-MS/MS method for the determination of baicalin in rat plasma,in order to study the effect of PEG400 on pharmacokinetics of baicalin and baicalein in normal and gut microbiotadysbiosis rats. Plasma was precipitated with ethyl acetate and determined by UPLC-MS/MS method,with genistein as an internal standard. In terms of specificity,linearity,range,accuracy,precision and stability,the method was suitable for the determination of baicalin in plasma. The gut microbiotadysbiosis rat model was induced through the oral administration with lincomycin hydrochloride(5 g·kg-1·d-1) for one week. Samples of plasma of rats were obtained at different time points,after the rats were administrated with baicalin,baicalin and PEG400. Baicalin in rats were detected by UPLC-MS/MS method,and pharmacokinetic parameters were calculated by DAS 3. 2. 2 software. The results showed that the ß-glucosidase activity and the number of colonies in the feces of gut microbiotadysbiosis rats induced by lincomycin hydrochloride were significantly reduced. The Cmaxand AUC0-tof the baicalinand PEG400 group in the intestinal flora were significantly lower than those in the normal rat baicalin and PEG400 group. There was no significant difference in Cmaxand AUC0-tbetween the baicalin group and the baicalin+PEG400 group of gut microbiotadysbiosis rats. The Cmaxand AUC0-tof the normal rats baicalin group were significantly higher than those of the gut microbiotadysbiosis rats baicalin group and the baicalin + PEG400 group. There was no significant difference in Cmaxand AUC0-tbetween the normal rat baicalein and PEG400 group and the baicalein group. The Cmaxand AUC0-tof the baicalein group in the gut microbiotadysbiosis rats were lower than those in the normal baicalein group,but significantly higher than those in the baicalein and PEG400 group. PEG400 could increase the absorption of baicalin in normal rats,but is ineffective in gut microbiotadysbiosis rats,with no impact on the absorption of baicalein in rats.

Cooperative Couplings between Octahedral Rotations and Ferroelectricity in Perovskites and Related Materials.

The structure of ABO_{3} perovskites is dominated by two types of unstable modes, namely, the oxygen octahedral rotation (AFD) and ferroelectric (FE) mode. It is generally believed that such AFD and FE modes tend to compete and suppress each other. Here we use first-principles methods to show that a dual nature of the FE-AFD coupling, which turns from competitive to cooperative as the AFD mode strengthens, occurs in numerous perovskite oxides. We provide a unified model of such a dual interaction by introducing novel high-order coupling terms and explain the atomistic origin of the resulting new form of ferroelectricity in terms of universal steric mechanisms. We also predict that such a novel form of ferroelectricity leads to atypical behaviors, such as an enhancement of all the three Cartesian components of the electric polarization under hydrostatic pressure and compressive epitaxial strain.

First-principles investigations of chirality in trimetallic alloy clusters: AlMnAun (n = 1-7).

Chirality, also called handedness, plays a crucial role in function ranging from biological self-assembly schemes, organic polymer functionalities, to optical material designs. In this Article, we demonstrated a first-principles investigation of chirality in magnetic AlMnAun(0/+1/-1) (n = 1-7) clusters. Optimized structures of the AlMnAun clusters exhibit configurational combinations between AlAun+1 and MnAun+1 clusters, indicating a subtle but equal competition between Au-Al and Au-Mn interactions in the alloy clusters. High magnetic moments are equal to or greater than 4µB in AlMnAun clusters due to the presence of the Mn dopant. Chirality turns up with the forms of right-handed and left-handed in stable AlMnAu5, AlMnAu6, and AlMnAu7 clusters. As a result, reflection symmetries are found in vibrational Raman and circular dichroism spectra of these chiral pairs. The present study shows that chiral magnetic clusters can be composed by doping two heteroatoms with one intrinsic magnetic dopant into small gold clusters.

SENP1 inhibits ferroptosis and promotes head and neck squamous cell carcinoma by regulating ACSL4 protein stability via SUMO1.

Head and neck squamous cell carcinoma (HNSCC) is currently one of the most common malignancies with a poor prognosis worldwide. Meanwhile, small ubiquitin­like modifier (SUMO) specific peptidase 1 (SENP1) was associated with ferroptosis. However, the specific functions and underlying mechanisms of action of SENP1 in ferroptosis and tumor progression of HNSCC remain to be established. The findings of the present study implicated a novel ferroptosis pathway in the initiation and progression of HNSCC, providing new functional targets to guide future therapy. In the present study, The Cancer Genome Atlas database was employed to establish a gene model related to ferroptosis and verified SENP1 as a key gene via transcriptome sequencing. Expression of SENP1 in HNSCC tissue and CAL­27 cells was detected based on reverse transcription­quantitative PCR and western blot analysis. Proliferation and migration abilities of cells were determined using Cell Counting Kit­8, wound healing and Transwell experiments. Expression levels of iron, glutathione (GSH) and lipid peroxidation end­product malondialdehyde (MDA) under conditions of silencing of SENP1 with shRNA lentivirus were assayed. Additionally, the relationship between SENP1 and long­chain acyl­coenzyme A synthase 4 (ACSL4) was validated with the aid of immunoblotting and co­immunoprecipitation (co­IP). Finally, the influence of shSENP1 on the expression of key ferroptosis proteins, glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11, was evaluated via western blotting. It was revealed that SENP1 was significantly overexpressed in HNSCC and associated with low patient survival. Silencing of SENP1 led to significant suppression of cell proliferation, migration and invasion, increase in the contents of iron ions and MDA and decline in GSH levels in HNSCC cells, thereby enhancing ferroptosis and inhibiting disease progression. Conversely, overexpression of SENP1 suppressed ferroptosis and promoted progression of HNSCC. Co­IP and western blot analyses revealed a SUMOylation link between SENP1 and ACSL4. SENP1 reduced the stability of ACSL4 protein through deSUMOylation, leading to inhibition of ferroptosis. SENP1 silencing further inhibited the expression of the key iron death protein, GPX4, to regulate ferroptosis. Taken together, SENP1 deficiency promoted ferroptosis and inhibited tumor progression through reduction of SUMOylation of ACSL4 in HNSCC. The collective results of the present study supported the utility of SENP1 as an effective predictive biomarker for targeted treatment of HNSCC.

Room-temperature chiral charge pumping in Dirac semimetals.

Chiral anomaly, a non-conservation of chiral charge pumped by the topological nontrivial gauge fields, has been predicted to exist in Weyl semimetals. However, until now, the experimental signature of this effect exclusively relies on the observation of negative longitudinal magnetoresistance at low temperatures. Here, we report the field-modulated chiral charge pumping process and valley diffusion in Cd3As2. Apart from the conventional negative magnetoresistance, we observe an unusual nonlocal response with negative field dependence up to room temperature, originating from the diffusion of valley polarization. Furthermore, a large magneto-optic Kerr effect generated by parallel electric and magnetic fields is detected. These new experimental approaches provide a quantitative analysis of the chiral anomaly phenomenon which was inaccessible previously. The ability to manipulate the valley polarization in topological semimetal at room temperature opens up a route towards understanding its fundamental properties and utilizing the chiral fermions.