Disulfide bond cleavage induced by a platinum(II) methionine complex

The cleavage of a disulfide bond and the redox equilibrium of thiol/disulfide are strongly related to the levels of glutathione (GSH)/oxidized glutathione (GSSG) or mixed disulfides in vivo. In this work, the cleavage of a disulfide bond in GSSG induced by a platinum(II) complex [Pt(Met)Cl2] (where Met = methionine) was studied and the cleavage fragments or their platinated adducts were identified by means of electrospray mass spectrometry, high-performance liquid chromatography, and ultraviolet techniques. The second-order rate constant for the reaction between [Pt(Met)Cl2] and GSSG was determined to be 0.4 M(-1) s(-1) at 310 K and pH 7.4, which is 100- and 12-fold faster than those of cisplatin and its monoaqua species, respectively. Different complexes were formed in the reaction of [Pt(Met)Cl2] with GSSG, mainly mono- and dinuclear platinum complexes with the cleavage fragments of GSSG. This study demonstrated that [Pt(Met)Cl2] can promote the cleavage of disulfide bonds. The mechanistic insight obtained from this study may provide a deeper understanding on the potential involvement of platinum complexes in the intracellular GSH/GSSG systems.     

Microwave assisted hydrothermal synthesis of tin niobates nanosheets with high cycle stability as lithium-ion battery anodes

SnNb₂O₆ and Sn₂Nb₂O₇ nanosheets were synthetized via microwave assisted hydrothermal method, and innovatively employed as anode materials for lithium-ion battery. Compared with Sn₂Nb₂O₇ and the previously reported pure Sn-based anode materials, the SnNb₂O₆ electrode exhibited outstanding cycling performance.     

Regioselective synthesis of 1,2,3-triazole derivatives via 1,3-dipolar cycloaddition reactions in water

Reaction of an arylacetylene with an azide in hot water gave 1,4-disubstituted 1,2,3-triazoles in high yields, while similar reaction between a terminal aliphatic alkyne and an azide (except m-nitroazidobenzene) afforded a mixture of regioisomers with the ratio of 1,4- to 1,5-isomers ranging from 3:1 to 28.6:1. Reactions of m-nitroazidobenzene with either arylalkynes or aliphatic alkynes formed only 1,4-disubstituted derivatives in excellent yields.     

A new tetrathiafulvalene–diamide cation salt with [Cu2Br4]2− anions

The title salt, bis[2,3‐bis(aminocarbonyl)‐8,9‐bis(methylsulfanyl)tetrathiafulvalenium] di‐μ‐bromido‐bis[bromidocopper(II)], (C₁₀H₁₀N₂O₂S₆)₂[Cu₂Br₄], contains 2,3‐bis(aminocarbonyl)‐8,9‐bis(methylsulfanyl)tetrathiafulvalenium radical cations, [DMT‐TTF(CONH₂)₂]^·+, and [Cu₂Br₄]²⁻ anions. The cations are associated across centres of inversion in a head‐to‐tail fashion via short face‐to‐face S...S stacking (TTF moiety). These dimers are further assembled into a one‐dimensional chain structure via interdimer double S...S contacts involving the methylsulfanyl groups. The one‐dimensional chains give rise to a two‐dimensional structure through intermolecular double N—H...O hydrogen bonds involving the amide group. The [Cu₂Br₄]²⁻ anions, which straddle centres of inversion, are located between the cation layers. Electron paramagnetic resonance measurements show a radical signal, indicating that the two TTF^·+ radicals are not completely coupled in the dimer.     

LapRLSR for NIR spectral modeling and its application to online monitoring of the column separation of Salvianolate

A novel near infrared (NIR) modeling method—Laplacian regularized least squares regression (LapRLSR) was presented, which can take the advantage of many unlabeled spectra to promote the prediction performance of the model even if there are only few calibration samples. Using LapRLSR modeling, NIR spectral analysis was applied to the online monitoring of the concentration of salvia acid B in the column separation of Salvianolate. The results demonstrated that LapRLSR outperformed partial least squares (PLS) significantly, and NIR online analysis was applicable.     

焦磷酸盐溶液中铜电沉积过程 Ⅱ. 用旋转电极的研究

焦磷酸铜络合物还原过程中要经过一价铜这个中间产物在一些文献中都假设过。这个问题不仅是有兴趣的理论问题,而且也很有实际价值。因为在工业电镀中经常出现的所谓“铜粉”,常常影响镀层的质量。简单的Cu~(2+)离子在氧化物溶液中进行阴极还原时,曾经用旋转圆环-圆盘电极(RRDE)的方法实验证实了一价铜中间产物的存在。但是在铜以络离子存在时,尤其是在过剩的焦磷酸离子存在下,使得还原在较负的电位下进行。这时是否有一价铜中间产物,尚未见到RRDE的研究。用RRDE研究络离子还原的工作还很少。可是这一有力方法的应用将会揭示许多一般方     

Speckle characteristics of simulated deep Fresnel region under shadowing effect

After the three-dimensional self-affine fractal random surface simulation, we use the optical scattering theory to calculate the deep Fresnel region speckle(DFRS) under consideration of the more strict shadowing effect. The evolution of DFRS with the scattering distance and the intensity probability distribution are studied. It is found that the morphology of the scatterer has an antisymmetric relationship with the intensity distribution of DFRS, and the effect of micro-lenses on the scattering surface causes the intensity probability distribution of DFRS to deviate from the Gaussian speckle in the high light intensity area.     

Picture Fuzzy Threshold Graphs with Application in Medicine Replenishment

In this study, a novel concept of picture fuzzy threshold graph (PFTG) is introduced. It has been shown that PFTGs are free from alternating 4-cycle and it can be constructed by repeatedly adding a dominating or an isolated node. Several properties about PFTGs are discussed and obtained the results that every picture fuzzy graph (PFG) is equivalent to a PFTG under certain conditions. Also, the underlying crisp graph (UCG) of PFTG is a split graph (SG), and conversely, a given SG can be applied to constitute a PFTG. A PFTG can be decomposed in a unique way and it generates three distinct fuzzy threshold graphs (FTGs). Furthermore, two important parameters i.e., picture fuzzy (PF) threshold dimension (TD) and PF partition number (PN) of PFGs are defined. Several properties on TD and PN have also been discussed. Lastly, an application of these developed results are presented in controlling medicine resources.     

Surface Functionalized Magnetic Nanoparticles as a Selective Sorbent for Affinity Fishing of PPAR-γ Ligands from Choerospondias axillaris

Coronary heart disease (CHD), which has developed into one of the major diseases, was reported to be treated by the target of peroxisome proliferators-activate receptor γ (PPAR-γ). As a natural medicine long used in the treatment of CHD, there are few studies on how to screen the target active compounds with high specific activity from Choerospondias axillaris. To advance the pace of research on target-specific active compounds in natural medicines, we have combined magnetic ligand fishing and functionalized nano-microspheres to investigate the active ingredients of PPAR-γ targets in Choerospondias axillaris. The PPAR-γ functionalized magnetic nano-microspheres have been successfully synthesized and characterized by vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The specificity, reusability, and reproducibility of the nano-microspheres were investigated with the help of the specific binding of rosiglitazone to PPAR-γ. In addition, the incubation temperature and the pH of the buffer solution in the magnetic ligand fishing were optimized to improve the specific adsorption efficiency of the analytes. Finally, with the aid of ultraperformance liquid chromatography plus Q-Exactive Orbitrap tandem mass spectrometry (UHPLC-Q-Exactive Orbitrap-MS/MS), the 16 active ligands including 9 organic acids, 5 flavonoids, and 2 phenols were found in the ethanolic extracts of Choerospondias axillaris. Therefore, the study can provide a successful precedent for realizing the designated extraction and rapid isolation of target-specific active ingredient groups in the complex mixtures.     

Quantum-Inspired Complex-Valued Language Models for Aspect-Based Sentiment Classification

Aiming at classifying the polarities over aspects, aspect-based sentiment analysis (ABSA) is a fine-grained task of sentiment analysis. The vector representations of current models are generally constrained to real values. Based on mathematical formulations of quantum theory, quantum language models have drawn increasing attention. Words in such models can be projected as physical particles in quantum systems, and naturally represented by representation-rich complex-valued vectors in a Hilbert Space, rather than real-valued ones. In this paper, the Hilbert Space representation for ABSA models is investigated and the complexification of three strong real-valued baselines are constructed. Experimental results demonstrate the effectiveness of complexification and the outperformance of our complex-valued models, illustrating that the complex-valued embedding can carry additional information beyond the real embedding. Especially, a complex-valued RoBERTa model outperforms or approaches the previous state-of-the-art on three standard benchmarking datasets.