Ethylene Polymerization and Copolymerization Using Nickel 2‑Iminopyridine‑<i>N</i>‑oxide Catalysts: Modulation of Polymer Molecular Weights and Molecular-Weight Distributions

Molecular weight and molecular-weight distribution are two critical parameters that determine the properties of a polyolefin material. In this contribution, we report the synthesis and characterization of a series of 2-iminopyridine-<i>N</i>-oxide nickel complexes; these catalysts demonstrate very high activities (up to 10⁷ g_PE mol_Ni^–1 h^–1) at very low methylaluminoxane loadings (80 equiv) during ethylene polymerization. By tuning the structures of the catalysts and the polymerization conditions, we show that it is possible to tune the polyethylene molecular weight (<i>M</i>_w: (0.3–301.6) × 10⁴), molecular-weight distribution (polydispersity index (PDI): 1.9–59.7), melting temperature (62.4–132.4 °C), and branching density (9–104/1000 C) over very wide ranges. This translates into the ability to tune the mechanical properties of these polymers as well as their complex viscosities. Equilibria between bis-ligated and mono-ligated nickel species are proposed to play important roles in this system. These nickel catalysts also mediate the efficient copolymerization of ethylene with methyl 10-undecenoate

Synthesis of Ultra-High-Molecular-Weight Polyethylene by Transition-Metal-Catalyzed Precipitation Polymerization

Ultra-high-molecular-weight polyethylene (UHMWPE) plays an important role in many important fields as engineering plastics. In this contribution, a precipitation polymerization strategy is developed by combination of highly active phosphino-phenolate nickel catalysts with polymer-insoluble solvent (heptane) to access UHMWPE (Mn up to 8.3 × 106 g mol–1) with good product morphology, free-flowing characteristics, and great mechanical properties. Compared with the academically commonly used aromatic solvent (toluene), the utilization of heptane offers simultaneous enhancement in important parameters including activity, polymer molecular weight, and catalyst thermal stability. This system can also generate polar functionalized UHMWPE with molecular weight of up to 1.6 × 106 g mol–1 in the copolymerization of ethylene with polar comonomers. More importantly, this precipitation polymerization strategy is generally applicable to several representative transition metal catalyst systems, leading to UHMWPE synthesis with good product morphology control

Improving the Dielectric Properties of Polymers by Incorporating Nano-particles.

The paper presents a brief review of the promise of nanotechnology applied to polymeric insulation materials and discusses the electrical properties found. For a variety of nanocomposites, the dielectric behaviour has shown that the interface between the embedded particles and host matrix holds the key to the understanding of the bulk phenomena being observed. Dielectric spectroscopy verified the motion of carriers through the interaction zones that surround the particles. The obvious improvements in endurance and breakdown strength of nanocomposites may be due to a reduction of charge accumulation. PEA space charge tests confirm this charge dissipation. By examining the onset field of space charge accumulation, it may be possible to determine whether a system is likely to be useful

Additional file 1 of Pretreatment prostate-specific antigen density as a predictor of biochemical recurrence in patients with prostate cancer: a meta-analysis

Supplementary Material

The influence of physical and chemical linkage on the properties of nanocomposites.

It has been shown by several groups that the mechanical and electrical behavior of composites changes quite substantially, and often beneficially, when the filler particle size is less than 100 nm in diameter. There is also good reason to believe that the interface between the embedded particulates and the polymer matrix holds the key to understanding the bulk phenomena observed. Materials based on an SiO2-polyolefin system have been formulated with functionalized particulates so as to affect the physical and chemical linkages. The agents used to achieve this include amino-silane, hexamethyl-disilazane and triethoxyvinylsilane. The emerging picture of the interface is supported by detailed dielectric spectroscopy and internal space charge assessment. The nature of the internal structure has been related to the bulk properties observed such as the breakdown strength, voltage endurance, and the measurement of internal charges resulting from interfacial polarization

Additional file 3: Table S4 of Decreased expression of the long noncoding RNA LINC00261 indicate poor prognosis in gastric cancer and suppress gastric cancer metastasis by affecting the epithelial–mesenchymal transition

Top-scoring genes which is enriched in the focal adhesion pathway according to LINC00261 expression. (XLS 10 kb

MOESM1 of Change of ranibizumab-induced human vitreous protein profile in patients with proliferative diabetic retinopathy based on proteomics analysis

Additional file 1. A supplementary description of methods for LC–MS/MS analysis and data analysis

CsPbBr₃ Perovskite Quantum Dot Vertical Cavity Lasers with Low Threshold and High Stability

All-inorganic cesium lead bromide (CsPbBr₃) perovskite quantum dots (QDs) have recently emerged as highly promising solution-processed materials for next-generation light-emitting applications. They combine the advantages of QD and perovskite materials, which makes them an attractive platform for achieving high optical gain with high stability. Here, we report an ultralow lasing threshold (0.39 μJ/cm²) from a hybrid vertical cavity surface emitting laser (VCSEL) structure consisting of a CsPbBr₃ QD thin film and two highly reflective distributed Bragg reflectors (DBRs). Temperature dependence of the lasing threshold and long-term stability of the device were also characterized. Notably, the CsPbBr₃ QDs provide superior stability and enable stable device operation over 5 h/1.8 × 10⁷ optical pulse excitations under ambient conditions. This work demonstrates the significant potential of CsPbBr₃ perovskite QD VCSELs for highly reliable lasers, capable of operating in the short-pulse (femtosecond) and quasi-continuous-wave (nanosecond) regimes

Additional file 1 of Integrated models of blood protein and metabolite enhance the diagnostic accuracy for Non-Small Cell Lung Cancer

Additional file 1: Supplementary Figure 1. GO Enrichment pathway associated with cellular component, and biological process. Supplementary Figure 2. The differentially expression of 10 plasma protein candidates among three groups. Supplementary Figure 3. The differentially expression of 14 serum amino acids among three groups. Supplementary Figure 4. The differentially expression of 15 bile acids among three groups. Supplementary Figure 5. The differentially expression of six classic tumor markers among three groups. Supplementary Figure 6. Proteins and amnio acids related to NSCLC stage. Supplementary Figure 7. Single index with AUC>0.7 for NSCLC screening. Supplementary Figure 8. Single index with AUC>0.7 in differentiating NSCLC and BPD. Supplementary Figure 9.The process and the result of binary logistic regression with backward elimination methods. Supplementary Table 1. Screened differentially expressed proteins and corresponding validation proteins. Supplementary Table 2. Performance of single predictor in NSCLC screening. Supplementary Table 3. Performance of single predictor in NSCLC diagnosis. Supplementary Table 4. Screening model by stepwise binary logistic regression analysis in training samples. Supplementary Table 5. Performance analysis of 3 models in screening NSCLC. Supplementary Table 6. Testing of 3 models in screening NSCLC. Supplementary Table 7. Diagnosis model by stepwise binary logistic regression analysis in training samples. Supplementary Table 8. Performance analysis of 3 models in differentiating NSCLC and BPD. Supplementary Table 9. Testing of 3 models in differentiating NSCLC and BPD. Supplementary Table 10. The concentration units of these candidates