Latest ArticlesRadiotherapy is one of the most important clinical cancer treatments, which works mainly by delivering a prescribed radiation dose to the tumor tissues. However, high doses of radiation may also lead many irreversible damages to the surrounding normal tissues. Thereby, how to effectively reduce these sideeffects has been a significant factor in influencing cancer therapeutic effect. In this work, we synthesized the hollow PtPd nanocubes with high-index facets, and investigated the radiation protection capability in vitro and in vivo. Our results showed the PtPd nanocrystals can decrease the ROS level and improve the survival rate of radiated cells. Meanwhile, survival rate of radiated mice can significantly increase from 0 to 30% after PtPd treatment. Consequently, the enzyme and ROS level in radiated mice can be recovered.
Nitrous oxide (N2O) is one of the significant greenhouse gases, and partial nitritation-anammox (PNA) process emits higher N2O than traditional nitrogen removal processes. N2O production in PNA mainly occurs in three different pathways, i.e., the ammonia oxidizing bacteria (AOB) denitrification, the hydroxylamine (NH2OH) oxidation and heterotrophic denitrifiers denitrification. N2O emission data vary significantly because of the different operational conditions, bioreactor configurations, monitoring systems and quantitative methods. Under the common operational parameter scopes of PNA, N2O emission via NH2OH oxidation dominates at relatively low dissolved oxygen (DO), low inorganic carbon (IC), high pH or low NO2- concentration, while N2O emission via AOB denitrification dominates at relative higher DO, higher IC, lower pH or higher NO2- concentration. AOB are highly enriched while nitriteoxidizing bacteria (NOB) are rarely found in partial nitritation process, and the order Nitrosomonadales of AOB is the dominant group and N2O producer. Anammox bacteria, AOB and certain amount of heterotrophic denitrifying bacteria are observed in the anammox process, the genus Denitratisoma and the heterotrophic denitrifying bacteria in the deep layer of anammox granules are the dominant N2O generation bacteria. In one-stage PNA reactors, anammox bacteria account for a large fraction of the biomass, AOB account for small portion, and NOB account for even less. The microbial community, diversity and N2O producers in one-stage PNA reactors are similar with those in two-stage PNA reactors. The dominant anammox bacteria, AOB and NOB in PNA are the species Candidatus Brocadia, the genera of Nitrotoga, Nitrospira and Nitrobacter, and the genus Nitrosomonas, respectively. The relations between N2O emission pathways and microbial communities need further study in the future.
We describe a simple method to prepare magnetic responsive polydivinylbenzene (PDVB) nanofiber composites by precipitated cationic living polymerization in the present of oleic acid capped Fe3O4 nanoparticles (NPs). The Fe3O4 NPs are encapsulated with the PDVB forming dendrites, from which thin nanofibers are grown in the tip-growth mode. The thin nanofibers are interwoven with the thick nanofibers forming robust composite network. The composites are magnetic responsive and highly efficient to gel almost all chemicals. Separation of the gelled chemicals from water becomes easier with a magnet. The performance is promising for magnetic collection of chemical spills.
The condensation reaction of ω-aminoalkyleneamide-functionalized pillar[5]arenes with 2-(4-([2, 2':6', 2''-terpyridin]-4'-yl)phenoxy)acetic acid or 4-(4-([2, 2':6', 2''-terpyridin]-4'-yl)phenoxy)butanoic acid in dry chloroform at room temperature under the catalysis of HOBT/EDCl resulted in novel pillar[5]arene diamido-bridged terpyridine derivatives. 1H NMR and 2D NOESY spectra clearly indicated that the interesting [1]rotaxanes were formed by longer alkylene such as propylene, butylene and hexylenediamido chains threading into the cavity of the pillar[5]arene and with larger terpyridine acting as the stopper. However, the shorter ethylenediamido chain only exists outer of cavity of pillar[5]arene and the molecule exist on free form.
Although intelligent hydrogels have shown bright potential application in biomedical fields, they were prepared by conventional methods and still face many serious challenges, such as uncontrollable stimulus-response and low response sensitivity. Recently, RAFT polymerization provides a versatile strategy for the fabrication of intelligent hydrogels with improved stimulus-response properties, owing to the ability to efficiently construct hydrogel precursors with well-defined structure, such as block copolymer, graft copolymer, star copolymer. In this review, we summarized the recent progress on intelligent hydrogels based on RAFT polymerization with emphasis on their fabrication strategies and applications for controlled drug delivery.
Two novel 2-(4-(9, 9-disubstitued-9H-fluoren-2-yl)phenyl)-9, 9-diethyl-1-phenyl-1, 9-dihydrofluoreno-[2, 3-d]imidazole derivatives 2a and 2b were synthesized and characterized. Their photophysical and electrochemical properties, thermal stability property, and electroluminescence (EL) performance of 2b were investigated. The fabricated device based on 2b doping into 4, 4'-N, N'-dicarbazole-biphenyl (5%) as an emitter present a maximum brightness of 1272 cd/m2 at 4 V with the CIE coordinate of (0.1590, 0.0465).
In recent years, the transition metal-free sulfenylation of C-H bond for C-S formation has been rapidly advanced and has become an eco-friendly synthetic tool for pharmacists and organic chemists. Various natural or bioactive molecules such as (hetero)arenes, olefins, carbonyl compounds, alkanes, have been employed for sulfenylating reactions. This review will focus on the recent five-year advances in C-S bond formation via direct sulfenylation of C(sp3)-H bonds under metal-free conditions and elaborate their mechanisms from a new perspective.
A new and convenient visible-light-induced method has been developed for the synthesis of sulfonylated benzofurans via oxidative cyclization reaction of 1, 6-enynes and arylsulfinic acids. This reaction was carried out under metal-free and mild conditions, in which the C-S, C-C and C=O bonds could be sequentially formed in one pot operation.
The enantioselective total synthesis of the putative structure of versiquinazoline H and three diastereomers has been achieved, which allowed the revision of the stereochemistry of this natural product. This six-step total synthesis relied on the evolution of the strategy that we previously developed, which features a DMDO-triggered tandem reaction. The modification of the lactamization step resulted in a significant improvement of yield that ensured the efficient total synthesis.
A new artificial transmembrane channel molecule bearing dihydrogen phosphate groups has been synthesized. The terminal dihydrogen phosphate groups enable the channel to be highly negatively charged at both ends of the channel structures. The artificial channel could incorporate into the lipid bilayer efficiently under low concentration. The channel displays high NH4+/K+ selectivity due to the electrostatic interaction and hydrogen bonding between NH4+ and the terminal dihydrogen phosphate groups.
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