Controlled chain-walking ethylene oligomerization in the gas-phase for hyperbranched ethylene oligomers.

Gas-phase polymerization is typically employed for the synthesis of high-molecular-weight crystalline polyolefin materials, yet the production of low-molecular-weight hyperbranched ethylene oligomers this method is seldom reported. In this study, we utilized flexible bulky iminopyridyl Pd(II) catalysts to catalyze the gas-phase oligomerization of ethylene, resulting in the preparation of hyperbranched ethylene oligomers. These catalysts demonstrated higher activity and stability comparable to those observed in solution polymerization, yielding hyperbranched ethylene oligomers with lower branching density and higher molecular weights.

Interpersonal brain synchronization during sensorimotor synchronization in people with different aerobic fitness levels: A fNIRS-based hyperscanning study.

Sensorimotor synchronization (SMS) refers to the temporal coordination of individual actions with perceptible external events and rhythms. Previous research has revealed a potential relationship between SMS abilities and physical activity, with proposed links to underlying inner-brain cognitive processes. However, it needs to be explored that whether good aerobic fitness will have a strong SMS ability, its internal mechanism, and the inter-brain mechanism.

Role of organic anion transporter 2 in the efflux of raltegravir glucuronide from the endoplasmic reticulum in the liver.

Endoplasmic reticulum (ER) type organic anion transporter 2 (OAT2) plays an essential role in the glucuronidation of certain drugs by mediating their uptake across ER membranes. However, the mechanism by which glucuronide conjugates generated in the ER lumen are excreted to the cytoplasm remains unclear. As plasma membrane-type OAT2-546aa has bidirectional transport properties, we hypothesized that glucuronide generated in the ER lumen may be exported from the ER via OAT2-548aa.

Lifespan trajectories of motor control and neural oscillations: A systematic review of magnetoencephalography insights.

Motor control (MC) evolves across the human lifespan, improving during childhood and adolescence, stabilizing in early adulthood, and declining in older age. These developmental and degenerative patterns are linked to neural oscillatory activity, which can be assessed via magnetoencephalography (MEG) to gain insights into motor planning, execution, termination, and command initiation. This review systematically examined age-related changes in MC and neural oscillations, centering on movement-related beta desynchronization (MRBD), post-movement beta rebound (PMBR), and movement-related gamma synchrony (MRGS).

Impact of Metal Species on Chain Transfer Mode in Bis(imino)pyridyl Complexes Catalyzed Ethylene Polymerization.

Chain transfer reactions are pivotal in coordination polymerization, influencing catalytic efficiency, molecular weight adjustment, and control over the chain-end structure. In this study, we present the synthesis and characterization of two bis(imino)pyridyl ligands featuring flexible -aryl cycloalkyl substituents, along with their corresponding iron(II) and cobalt(II) complexes. These complexes exhibited very high polymerization activities, reaching up to 1.

Controlled oligomerization in water to hyperbranched ethylene oligomers.

The production of high molecular weight polyethylene particles in aqueous environments has received considerable attention, yet reports on the formation of polyethylene oil within water remain scarce. Herein, we present findings that demonstrate the oligomerization of ethylene by certain iminopyridyl Pd(II) catalysts in water, resulting in the synthesis of hyperbranched ethylene oligomers. It is worth highlighting the intriguing observation that these catalysts exhibited a remarkable catalytic longevity in aqueous medium and ultimately facilitated the generation of a substantial liquid polyolefin phase from water.

Synthesis of Ultralow-Density Polyethylene Elastomers Using Triarylnaphthyl Iminopyridyl Ni(II) Catalysts.

Recently, the chain-walking ethylene polymerization strategy has garnered widespread attention as an efficient and straightforward method for preparing polyolefin elastomers. In this study, a series of 2,4,8-triarylnaphthyl iminopyridyl nickel catalysts were synthesized and used in ethylene polymerization. These catalysts demonstrated moderate catalytic activity (10 g mol h), producing high-molecular-weight (up to 145.

Forkhead box M1 mediates metabolic reprogramming in human colorectal cancer cells.

Metabolic reprogramming is recognized as a hallmark of cancer, enabling cancer cells to acquire essential biomolecules for cell growth, often characterized by upregulated glycolysis and/or fatty acid synthesis-related genes. The transcription factor forkhead box M1 (FOXM1) has been implicated in various cancers, contributing significantly to their development, including colorectal cancer (CRC), a major global health concern. Despite FOXM1's established role in cancer, its specific involvement in the Warburg effect and fatty acid biosynthesis in CRC remains unclear.

Endoplasmic reticulum transporter OAT2 regulates drug metabolism and interaction.

Xenobiotic metabolic reactions in the hepatocyte endoplasmic reticulum (ER) including UDP-glucuronosyltransferase and carboxylesterase play central roles in the detoxification of medical agents with small- and medium-sized molecules. Although the catalytic sites of these enzymes exist inside of ER, the molecular mechanism for membrane permeation in the ER remains enigmatic. Here, we investigated that organic anion transporter 2 (OAT2) regulates the detoxification reactions of xenobiotic agents including anti-cancer capecitabine and antiviral zidovudine, via the permeation process across the ER membrane in the liver.

Impact of -aryl halogen effects on ethylene polymerization: steric electronic effects.

Ligand steric hindrance and electronic effects play a crucial role in late-transition metal-catalyzed olefin polymerization. In this research, a series of -aryl halogenated α-diimine ligands bearing bulky dibenzhydryl substituents, along with their corresponding nickel catalysts, have been synthesized and thoroughly characterized. The nickel catalysts demonstrated very high activity in ethylene polymerization, achieving a high rate of up to 10 g mol h.

Flexible Axial Shielding Strategy for Improving Ethylene (Co)polymerization with 8-Cycloalkylnaphthyl α-Diimine Catalysts.

8-aryl or alkyl-naphthyl substituents are widely used as an effective axial shielding strategy for the suppression of chain transfer in late-transition metal-catalyzed ethylene (co)polymerization to yield high molecular weight polyethylene and copolymers. In this study, two 8-cycloalkylnaphthyl acenaphthene-based α-diimine ligands and the corresponding four nickel and palladium complexes were designed and synthesized to explore the effect of axial flexible shielding on ethylene (co)polymerization. In ethylene polymerization, the nickel complexes displayed high activities (up to 1.

Renal Pharmacokinetic Adaptation to Cholestasis Causes Increased Nephrotoxic Drug Accumulation by Mrp6 Downregulation in Mice.

In hepatic dysfunction, renal pharmacokinetic adaptation can be observed, although information on the changes in drug exposure and the interorgan regulation of membrane transporters in kidney in liver diseases is limited. This study aimed to clarify the effects of renal exposure to nephrotoxic drugs during cholestasis induced by bile duct ligation (BDL). Among the 11 nephrotoxic drugs examined, the tissue accumulation of imatinib and cisplatin in kidney slices obtained from mice 2 weeks after BDL operation was higher than that in sham-operated mice.

Direct Synthesis of Polyethylene Thermoplastic Elastomers Using Hybrid Bulky Acenaphthene-Based α-Diimine Ni(II) Catalysts.

Recently, polyolefin thermoplastic elastomers can be obtained directly using ethylene as a single feedstock via α-diimine nickel-catalyzed ethylene chain walking polymerization. Here, a new range of bulky acenaphthene-based α-diimine nickel complexes with hybrid -phenyl and -diarylmethyl anilines were constructed and applied to ethylene polymerization. All the nickel complexes under the activation of excess EtAlCl exhibited good activity (level of 10 g mol h) and produced polyethylene with high molecular weight (75.

Effects of aquatic exercise on the improvement of lower-extremity motor function and quality of life in patients with Parkinson's disease: A meta-analysis.

To systematically evaluate the effect of aquatic exercise interventions on the improvement of lower-extremity motor function and quality of life in patients with Parkinson's disease. Two researchers independently searched the literature using the PubMed, Web of Science, Embase, and Cochrane Library databases. The search period was from the establishment of the database to December 2021.

Direct Synthesis of Partially Chain-Straightened Propylene Oligomers and P-MA Co-Oligomers Using Axially Flexible Shielded Iminopyridyl Palladium Complexes.

In this study, a series of partially chain-straightened propylene oligomers and functional propylene−methyl acrylate (P-MA) co-oligomers were synthesized with 8-alkyl-iminopyridyl Pd(II) catalysts. The molecular weight and polar monomer incorporation ratio could be tuned by using Pd(II) catalysts with various 8-alkyl-naphthyl substituents (8-alkyl: H, Me, and n-Bu). In propylene oligomerization, all the 8-alkyl-iminopyridyl Pd(II) catalysts convert propylene to partially chain-straightened (119−136/1000 C) oligomers with low molecular weights (0.

Ethylene (co) oligomerization using iminopyridyl Ni(II) and Pd(II) complexes bearing benzocycloalkyl moieties to access hyperbranched ethylene oligomers and ethylene-MA co-oligomers.

Hyperbranched ethylene oligomers and polar functionalized co-oligomers synthesized ethylene chain walking (co) oligomerization is a very attractive strategy. In this study, a series of dibenzhydryl iminopyridyl ligands with benzocycloalkyl and naphthyl moieties and the corresponding Ni(II) and Pd(II) complexes were synthesized and characterized. The Ni(II) complexes were highly effective in ethylene oligomerization and ethylene oligomers with hyperbranched microstructures were generated from this system.

Direct Synthesis of Chain-End Toluene Functionalized Hyperbranched Ethylene Oligomers.

Chain-end functionalized polymers play an important role in the field of building complex macromolecular structures. In this study, we have synthesized and characterized four dibenzhydryl iminopyridine Ni(II) complexes bearing remote flexible substituents (Et and n-Bu) to provide hyperbranched ethylene oligomers in ethylene oligomerization with moderate to good activities. Most notably, toluene-end-functionalized hyperbranched ethylene oligomers were obtained under elevated temperature conditions and validated by NMR.

Synthesis of High-Molecular-Weight Branched Polyethylene Using a Hybrid "Sandwich" Pyridine-Imine Ni(II) Catalyst.

Most pyridine-imine Ni(II) and Pd(II) catalysts tend to yield low-molecular-weight polyethylene and ethylene-based copolymers in olefin insertion polymerization, as the unilateral axial steric structure of such complexes often cannot provide effective shielding of the metal center. In this study, we synthesized a series of hybrid "semi-sandwich" and "sandwich" type pyridine-imine Ni(II) complexes by incorporating diarylmethyl or dibenzosuberyl groups onto 8-aryl-naphthyl motif. The as-prepared Ni(II) complexes afforded highly branched polyethylene with high molecular weights (level of 10 g/mol), and moderate activities (level of 10 g/(molh)) in ethylene polymerization.

Exploring the Relationship between the Polyethylene Microstructure and Spatial Structure of α-Diimine Pd(II) Catalysts via a Hybrid Steric Strategy.

The branching density of polyethylene generated in the α-diimine Pd(II) system is usually very high, largely independent of simple ligand modifications with steric or electronic perturbations, or the polymerization conditions. In this study, we designed and synthesized a class of bulky hybrid α-diimine Pd(II) catalysts combining -diarylmethyl and -phenyl moieties to explore the relationship between the polyethylene microstructure and the spatial structure of catalysts. In ethylene polymerization, the hybrid α-diimine Pd(II) catalysts exhibited high activities (well above 10 g·mol·h) and yielded highly branched (90-110/1000C) polyethylenes with high molecular weights (up to 278.

Facile Synthesis of Hyperbranched Ethylene Oligomers and Ethylene/Methyl Acrylate Co-oligomers with Different Microscopic Chain Architectures.

Low-molecular-weight (MW) ethylene oligomers with hyperbranched microstructures are often difficult to be synthesized by traditional catalytic processes. In this study, a series of -terphenyl iminopyridyl ligands and the corresponding Pd(II) and Ni(II) complexes bearing remote conjugated substituents with different electronic effects (H, Me, F, Cl, and Bu) were synthesized in a simple and efficient way. These Pd(II) and Ni(II) complexes were highly effective in the ethylene oligomerization and co-oligomerization with methyl acrylate (MA).

Flexible "Sandwich" (8-Alkylnaphthyl α-Diimine) Catalysts in Insertion Polymerization.

8-Arylnaphthyl substituents are privileged motifs frequently integrated into late-transition-metal catalysts, endowing them with an ability to retard chain transfer in ethylene polymerization. In this contribution, we disclose a sort of novel α-diiminenickel and -palladium complexes containing flexible 8-alkylnaphthyl in lieu of rigid 8-arylnaphthyl and their catalytic performance in ethylene polymerization. An interesting feature of these 8-alkylnaphthyl-substituted α-(diimine)PdMeCl complexes is that they present as a mixture of syn and anti isomers (syn:anti = ca.

Efficient Suppression of Chain Transfer and Branching via C -Type Shielding in a Neutral Nickel(II) Catalyst.

An effective shielding of both apical positions of a neutral Ni active site is achieved by dibenzosuberyl groups, both attached via the same donors' N-aryl group in a C -type arrangement. The key aniline building block is accessible in a single step from commercially available dibenzosuberol. This shielding approach suppresses chain transfer and branch formation to such an extent that ultrahigh molecular weight polyethylenes (5×10  g mol ) are accessible, with a strictly linear microstructure (<0.

A Self-Supporting Strategy for Gas-Phase and Slurry-Phase Ethylene Polymerization using Late-Transition-Metal Catalysts.

The polyolefin industry is dominated by gas-phase and slurry-phase polymerization using heterogeneous catalysts. In contrast, academic research is focused on homogeneous systems, especially for late-transition-metal catalysts. The heterogenization of homogeneous catalysts is a general strategy to provide catalyst solutions for existing industrial polyolefin synthesis.

Direct Synthesis of Branched Carboxylic Acid Functionalized Poly(1-octene) by α-Diimine Palladium Catalysts.

In this work, we studied propylene polymerization using some α-diimine palladium catalysts with systematically varied ligand sterics. In propylene polymerization, the ligand steric effect exhibits significant variations on the catalytic activity, polymer molecular weight, and branching density. However, the regio control for the polymer microstructure is poor.