Activity

The reactions of a number of rare-earth (RE) trichlorides and an oligosilanylene diide containing a siloxane unit in the backbone in DME are described. The formed products of the type [(DME)4·K][(DME)·RE(Cl)2Si(SiMe3)2SiMe22O] (RE = Y, La, Ce, Pr, Sm, Tb, Dy, and Er) are disilylated dichloro metalate complexes and include the first examples of Si-La and Si-Pr compounds as well as the first structurally characterized example of a Si-Dy complex. A most intriguing aspect of the synthesis of these complexes is that they offer entry into a systematic study of the still largely unexplored field of silyl RE complexes by the possibility of ligand exchange reactions under preservation of the Si-RE interaction. This was demonstrated by the conversion of [(DME)4·K][(DME)·RE(Cl)2Si(SiMe3)2SiMe22O] to [(DME)4·K][Cp2YSi(SiMe3)2SiMe22O].Biomass bifunctional polyamide elastomers (BbPEs) were successfully prepared from dimer acid (DA), trimer acid (TA), and triethylenetetramine with shape memory and self-healing abilities. In the composition structure of BbPEs, vast hydrogen bonds formed among the amide bonds of different segments endowed the BbPEs with self-healing ability. At room temperature, the mechanical properties of BbPEs can be restored to 49% of the original condition after healing for 2 h. In addition, the physical and chemical cross-linking endowed the BbPE with preferable mechanical and shape memory properties. The tensile strength of the material is 4.4 ± 0.1 MPa, and the elongation at break reaches 1500 ± 2%. Under the recovery temperature of 60 °C, the shape memory recovery rate of 5 min can reach 95%. The recovery efficiency is 88.9%. This material can be utilized for many practical applications, such as intelligent electronic devices, bionic materials, and so on.Phosphodiester bonds in the backbones of double-stranded (ds)RNA and single-stranded (ss)RNA are known to undergo alkaline hydrolysis. Consequently, dsRNA agents used in emerging RNA interference (RNAi) products have been assumed to exhibit low chemical persistence in solutions. However, the impact of the duplex structure of dsRNA on alkaline hydrolysis has not yet been evaluated. In this study, we demonstrated that dsRNA undergoes orders-of-magnitude slower alkaline hydrolysis than ssRNA. Furthermore, we observed that dsRNA remains intact for multiple months at neutral pH, challenging the assumption that dsRNA is chemically unstable. read more In systems enabling both enzymatic degradation and alkaline hydrolysis of dsRNA, we found that increasing pH effectively attenuated enzymatic degradation without inducing alkaline hydrolysis that was observed for ssRNA. Overall, our findings demonstrated, for the first time, that key degradation pathways of dsRNA significantly differ from those of ssRNA. Consideration of the unique properties of dsRNA will enable greater control of dsRNA stability during the application of emerging RNAi technology and more accurate assessment of its fate in environmental and biological systems, as well as provide insights into broader application areas including dsRNA isolation, detection and inactivation of dsRNA viruses, and prebiotic molecular evolution.Airborne polychlorinated biphenyl (PCB) concentrations are higher indoors than outdoors due to their historical use in building materials and their presence in modern paints and surface treatments. For some populations, including school children, PCB levels indoors result in inhalation exposures that may be greater than or equivalent to exposure through diet. In a school, PCB exposure may come from multiple sources. We hypothesized that there are both Aroclor and non-Aroclor sources within a single school and that PCB concentration and congener profiles differ among rooms within a single building. To evaluate this hypothesis and to identify potential localized sources, we measured airborne PCBs in nine rooms in a school. We found that schoolroom concentrations exceed outdoor air concentrations. Schoolroom concentrations and congener profiles also varied from one room to another. The concentrations were highest in the math room (35.75 ng m-3 ± 8.08) and lowest in the practice gym (1.54 ng m-3 ± 0.35). Rooms in the oldest wing of the building, originally constructed between 1920 and 1970, had the highest concentrations. The congener distribution patterns indicate historic use of Aroclor 1254 as well as modern sources of non-Aroclor congeners associated with paint pigments and surface coatings. Our findings suggest this noninvasive source identification method presents an opportunity for targeted source testing for more cost-effective prioritization of materials remediation in schools.Nanozymes can mimic the activities of diverse enzymes, and this ability finds applications in analytical sciences and industrial chemistry, as well as in biomedical applications. Among the latter, prodrug conversion mediated by nanozymes is investigated as a step toward site-specific drug synthesis, to achieve localized therapeutic effects. In this work, we investigated a ceria nanozyme as a mimic to phosphatase, to mediate conversion of phosphate prodrugs into corresponding therapeutics. To this end, the substrate scope of ceria as a phosphatase mimic was analyzed using a broad range of natural phosphor(di)esters and pyrophosphates. Knowledge of this scope guided the selection of existing phosphate prodrugs that can be converted by ceria into the corresponding therapeutics. “Extended scaffold phosphates” were engineered using self-immolative linkers to accommodate a prodrug design for amine-containing drugs, such as monomethyl auristatin E. Phosphate prodrugs masked activity of the toxin, whereas prodrug conversion mediated by the nanozyme restored drug toxicity, which was validated in mammalian cell culture. The main novelty of this work lies in the rational pairing of the ceria nanozyme with the existing and the de novo designed “extended scaffold” phosphate prodrugs toward their use in nanozyme-prodrug therapy based on the defined nanozyme substrate scope.As one of the CO2 capture and utilization technologies, Li-CO2 batteries have attracted special interest in the application of carbon neutral. However, the design and fabrication of a low-cost high-efficiency cathode catalyst for reversible Li2CO3 formation and decomposition remains challenging. Here, guided by theoretical calculations, CO2 was utilized to activate the catalytic activity of conventional nitrogen-doped graphene, in which pyridinic-N and pyrrolic-N have a high total content (72.65%) and have a high catalytic activity in both CO2 reduction and evolution reactions, thus activating the reversible conversion of Li2CO3 formation and decomposition. As a result, the designed cathode has a low voltage gap of 2.13 V at 1200 mA g-1 and long-life cycling stability with a small increase in the voltage gap of 0.12 V after 170 cycles at 500 mA g-1. Our work suggests a way to design metal-free catalysts with high activity that can be used to activate the performance of Li-CO2 batteries.