The nonpolar nature of polyolefins is one of their biggest limitations. Now, an efficient route to generate polar‐functionalized, crosslinkable, self‐healing, photoresponsive polyolefins with ...thermoplastic, elastomeric, and thermosetting properties is reported. Tunable amounts of carboxylic acid and a cyclic comonomer are installed onto polyolefins by palladium‐catalyzed terpolymerization reactions. The incorporated carboxylic acid unit can alter the surface properties of polyolefins. The subsequently introduced Fe3+/citric acid combination induces dynamic crosslinking and enables self‐healing. Under UV light irradiation, citric acid reduces Fe3+ to Fe2+ and decreases the crosslinking density. The Fe2+ moiety can be easily oxidized back to Fe3+, making the process reversible at the expense of citric acid. The incorporated cyclic comonomer modulates the crystallinity of polyolefins, provides elastic properties, and installs carbon–carbon double bonds for sulfur‐induced vulcanization.
Going polar: An efficient route is reported to generate polar‐functionalized, crosslinkable, self‐healing, and photoresponsive polyolefins with thermoplastic, elastomeric, and thermosetting properties.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The heterogenization of homogeneous metal complexes on solid supports presents an efficient strategy for bridging homogeneous catalysts with industrially-preferred heterogeneous catalysts; however, a ...series of drawbacks restrict their implementation in olefin polymerization, particularly for copolymerization with polar comonomers. In this contribution, we report an ionic anchoring strategy that is highly versatile, generally applicable to different systems, and enables strong catalyst-support interactions while tolerating various polar functional groups. In addition to greatly enhanced polymerization properties, the supported catalysts achieved higher comonomer incorporation than their unsupported counterparts. This strategy enabled efficient polymerization at high temperatures at large scale and great control over product morphology, and the facile synthesis of polyolefin composites. More importantly, the dispersion of different fillers in the polyolefin matrix produced great material properties even at low composite loadings. It is expected that this strategy will find applications in different catalytic systems and the synthesis of advanced engineering materials.
Since polar groups can poison the metal centers in catalysts, the incorporation of polar comonomers usually comes at the expense of catalytic activity and polymer molecular weight. In this ...contribution, we demonstrate polar bimodal polyethylene as a potential solution to this trade-off. The more-polar/more-branched low-molecular-weight fraction provides polarity and processability, while the less-polar/less-branched high-molecular-weight fraction provides mechanical and melt properties. To achieve high miscibility between these two fractions, three synthetic routes are investigated: mixtures of homogeneous catalysts, separately supported heterogeneous catalysts, and a co-anchoring strategy (CAS) to heterogenize different homogeneous catalysts on one solid support. The CAS route is the only viable strategy for the synthesis of polar bimodal polyethylene with good molecular level entanglement and minimal phase separation. This produces polyolefin materials with excellent mechanical properties, surface/dyeing properties, gas barrier properties, as well as extrudability and 3D-printability.
Perovskite light-emitting diodes (PeLEDs) have undergone rapid development in the last several years with external quantum efficiencies (EQEs) reaching over 21%. However, most PeLEDs still suffer ...from severe efficiency roll-off (droop) at high injection current densities, thus limiting their achievable brightness and presenting a challenge to their use in laser diode applications. In this work, we show that the roll-off characteristics of PeLEDs are affected by a combination of charge injection imbalance, nonradiative Auger recombination, and Joule heating. To realize ultrabright and efficient PeLEDs, several strategies have been applied. First, we designed an energy ladder to balance the electron and hole transport. Second, we optimized perovskite materials to possess reduced Auger recombination rates and improved carrier mobility. Third, we replaced glass substrates with sapphire substrates to better dissipate joule heat. Finally, by applying a current-focusing architecture, we achieved PeLEDs with a record luminance of 7.6 Mcd/m2. The devices can be operated at very high current densities (J) up to ∼1 kA/cm2. Our work suggests a broad application prospect of perovskite materials for high-brightness LEDs and ultimately a potential for solution-processed electrically pumped laser diodes.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Norbornene and derivatives represent an important class of comonomers in polyolefin synthesis due to their unique cyclic structures. In this contribution, two groups of norbornene comonomers are ...investigated. The diene-type comonomer (dicyclopentadiene and ethylidene norbornene) provides additional active sites for sulfur vulcanization. The second group contains polar-functionalized norbornenes bearing acetate, hydroxyl, and carboxylic acid substituents, which can efficiently alter the non-polar nature of polyolefin materials. Palladium-catalyzed terpolymerization of ethylene with these two groups of comonomers leads to the formation of polar-functionalized polyolefin elastomers with a high molecular weight and high comonomer content. The polymeric products possess great mechanical and elastic properties, which can be further improved through sulfur vulcanization. The polar substituents render these polymers widely tunable surface properties, dyeing properties, blending capabilities, adhesive properties, and adsorption capacities toward various organic solvents.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Pancreatic cancer is one of the most lethal diseases which lack an early diagnostic marker. We investigated whether serum ferritin (SF) reflects risk for pancreatic cancer and potential genes that ...may contribute ferritin and pancreatic cancer risks. We performed a meta-analysis of relevant studies on SF and pancreatic cancer risk by searching articles in PUBMED and EMBASE published up to 1 March 2020. We also collected serum samples from Taipei Medical University Joint Biobank and compared SF levels in 34 healthy controls and 34 pancreatic cancer patients. An Oncomine database was applied as a platform to explore a series of genes that exhibited strong associations between ferritin and pancreatic cancer. Herein, we show that high levels of SF can indicate risk of pancreatic cancer, suggesting SF as the new tumor marker that may be used to help pancreatic cancer diagnosis. We also found that expressions of iron homeostasis genes (MYC, FXN) and ferroptosis genes (ALOX15, CBS, FDFT1, LPCAT3, RPL8, TP53, TTC35) are significantly altered with pancreatic tumor grades, which may contribute to differential expression of ferritin related to pancreatic cancer prognosis.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Metal halide perovskites are emerging as attractive materials for light-emitting diode (LED) applications. The external quantum efficiency (EQE) has experienced a rapid progress and reached over 21%, ...comparable to the state of the art organic and quantum dot LEDs. For metal halide perovskites, their simple solution-processing preparation, facile band gap tunability, and narrow emission line width provide another attractive route to harness their superior optoelectronic properties for multicolor display applications. In this work, we demonstrate a high-resolution, large-scale photolithographic method to pattern multicolor perovskite films. This approach is based on a dry lift-off process which involves the use of parylene as an intermediary and the easy mechanical peeling-off of parylene films on various substrates. Using this approach, we successfully fabricated multicolor patterns with red and green perovskite pixels on a single substrate, which could be further applied in liquid crystal displays (LCDs) with blue backlight. Besides, a prototype green perovskite micro-LED display under current driving has been demonstrated.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Intrauterine adhesion refers to endometrial repair disorders which are usually caused by uterine injury and may lead to a series of complications such as abnormal menstrual bleeding, recurrent ...abortion and secondary infertility. At present, therapeutic approaches to intrauterine adhesion are limited due to the lack of effective methods to promote regeneration following severe endometrial injury. Therefore, to develop new methods to prevent endometrial injury and intrauterine adhesion has become an urgent need. For severely damaged endometrium, the loss of stem cells in the endometrium may affect its regeneration. This article aimed to discuss the characteristics of various stem cells and their applications for uterine tissue regeneration.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Aims
To assess the associations of diabetes duration and glycaemic control (defined by plasma glycated haemoglobin HbA1c level) with the risks of cardiovascular disease (CVD) and all‐cause mortality ...and to determine whether the addition of either or both to the established CVD risk factors can improve predictions.
Materials and Methods
A total of 435 679 participants from the UK Biobank without CVD at baseline were included. Cox models adjusting for classic risk factors (sociodemographic and anthropometric characteristics, lipid profiles and medication use) were used, and predictive utility was determined by the C‐index and net reclassification improvement (NRI).
Results
Compared with participants without diabetes, participants with longer diabetes durations and poorer glycaemic control had a higher risk of fatal/nonfatal CVD. Among participants with diabetes, the fully‐adjusted hazard ratios (HRs) for diabetes durations of 5 to <10 years, 10 to <15 years and ≥15 years were 1.15 (95% confidence interval CI 0.99, 1.34), 1.50 (95% CI 1.26, 1.79) and 2.22 (95% CI 1.90, 2.58; P‐trend <0.01), respectively, compared with participants with diabetes durations <5 years. In addition, those with the longest disease duration (≥15 years) and poorer glycaemic control (HbA1c ≥64 mmol/mol 8%) had the highest risk of fatal/nonfatal CVD (HR 3.12, 95% CI 2.52, 3.86). Among participants with diabetes, the addition of both diabetes duration and glycaemic control levels significantly improved both the C‐index (change in C‐index +0.0254; 95% CI 0.0111, 0.0398) and the overall NRI for fatal/nonfatal CVD (0.0992; 95% CI 0.0085, 0.1755) beyond the use of the classic risk factors.
Conclusions
Both longer diabetes duration and poorer glycaemic control were associated with elevated risks of CVD and mortality. Clinicians should consider not only glycaemic control but also diabetes duration in CVD risk assessments for participants with diabetes.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Alzheimer's disease is characterized by sustained neuroinflammation leading to memory loss and cognitive decline. The past decade has witnessed tremendous efforts in Alzheimer's disease research; ...however, no effective treatment is available to prevent disease progression. An increasing body of evidence suggests that neuroinflammation plays an important role in Alzheimer's disease pathogenesis, alongside the classical pathological hallmarks such as misfolded and aggregated proteins (e.g., amyloid-beta and tau). Firstly, this review summarized the clinical and pathological characteristics of Alzheimer's disease. Secondly, we outlined key aspects of glial cell-associated inflammation in Alzheimer's disease pathogenesis and provided the latest evidence on the roles of microglia and astrocytes in Alzheimer's disease pathology. Then, we revealed the double-edged nature of inflammatory cytokines and inflammasomes in Alzheimer's disease. In addition, the potential therapeutic roles of innate immunity and neuroinflammation for Alzheimer's disease were also discussed through these mechanisms. In the final section, the remaining key problems according to the current research status were discussed.
PDF
