Latest ArticlesPd-catalyzed oxidative homocoupling of 2-arylquinazolinones was successfully developed for the direct construction of biaryls via C-H bond activation. New well-defined structure that possessed two quinazolinone units was obtained with high efficiency and atomic economy. The protocols offer an efficient approach to the synthetically useful and functionalized biaryls in good yields using quinazolinone as a directing group.
Li2FeTiO4 composites have been produced using commercial LiAC, FeCl2 and different titanium sources by hydrothermal synthesis (HS) at 175 ℃ and subsequent annealing at 700 ℃. Impure phase TiO2, Fe2O3 and FeTiO4 were detected out among the Li2FeTiO4 composites with different titanium sources. Micron and nano-sized particles of Li2FeTiO4 were prepared from various titanium raw materials, with nano-sized particles predominating when titanium raw materials were layered hydrogen titanate nanowire (H2Ti3O7NW, HTO-NW) and titanium oxide nanotubes (TiO2NB). The Li2FeTiO4 composites synthesized by HTO-NW shows a primary particle size of 50-200 nm of high crystallinity staggered with undissolved nanowire with a diameter size of about 100 nm. The samples using one-dimensional nanometer titanium oxide (TiO2 NB) as the raw material can get a super high initial discharge capacity of 367.8 mAh/g at the rate of C/10 and excellent cycling stability. The selection of raw materials and adopting multi-phase modification can be considered as an effective strategy to improve the electro-chemical properties of Li2FeTiO4 composite cathode materials for the lithium secondary battery.
The binding behavior of pillar[5]arenes (P5As) towards a series of olefin guests ((E)-1, 4-dichlorobut-2-ene (1E), (Z)-1, 4-dichlorobut-2-ene (1Z), (E)-but-2-ene-1, 4-diol (2E), and (Z)-but-2-ene-1, 4-diol (2Z), as well as an alkyne derivative 1, 4-dichlorobut-2-yne (3)) have been studied in organic solution. P5As exhibit considerable selectivities for the trans-olefin isomers (1E and 2E) over their cis-isomers (1Z and 2Z). The cis/trans-selective interactions hold the potential of utilizing P5As to separate olefin isomers.
The development of heterogeneous catalysts with substrate shape, size or electronic constitution selectivity is a huge challenge in photocatalysis. Reported herein is a host-guest interaction strategy to endow photocatalysts with special selectivity. By adjusting the precursors, conjugated macrocycle polymers (CMPs) with pillar[5]arene struts (CMP-1 and CMP-2) and a corresponding non-pillar[5]arene-contained conjugated organic polymer (COP-1) were prepared and the photocatalytic activities toward sulfide derivatives were investigated. The sulfides showed similar conversions when COP-1 was used as a photocatalyst, but exhibited significant differences when it turned to the CMPs. Remarkably, the conversion yield of S-1 achieved near 18 folds over the one of S-2 when CMP-2 was used as a catalyst. Mechanism studies confirmed that the "host-guest" effect of pillar[5]arene struts in CMPs was the main cause of the difference. The present work establishes CMPs as novel heterogeneous photocatalysts with substrate selectivity, and such a method will inspire the researchers concerning preparation of heterogeneous catalysts with excellent selectivity.
The rapid identification of pathogens is crucial in controlling the food quality and safety. The proposed system for the rapid and label-free identification of pathogens is based on the principle of laser scattering from the bacterial microbes. The clinical prototype consists of three parts: the laser beam, photodetectors, and the data acquisition system. The bacterial testing sample was mixed with 10 mL distilled water and placed inside the machine chamber. When the bacterial microbes pass by the laser beam, the scattering of light occurs due to variation in size, shape, and morphology. Due to this reason, different types of pathogens show their unique light scattering patterns. The photo-detectors were arranged at the surroundings of the sample at different angles to collect the scattered light. The photodetectors convert the scattered light intensity into a voltage waveform. The waveform features were acquired by using the power spectral characteristics, and the dimensionality of extracted features was reduced by applying minimal-redundancy-maximal-relevance criterion (mRMR). A support vector machine (SVM) classifier was developed by training the selected power spectral features for the classification of three different bacterial microbes. The resulting average identification accuracies of E. faecalis, E. coli and S. aureus were 99%, 87%, and 94%, respectively. The overall experimental results yield a higher accuracy of 93.6%, indicating that the proposed device has the potential for label-free identification of pathogens with simplicity, rapidity, and cost-effectiveness.
The copper(II) diethyldithiocarbamate (Cu(DDC)2) complex exhibited excellent inhibition to cancer cells. The usual administration is intravenous injection for disulfram and oral for copper. A new strategy was reported to improve the administration efficiency of the Cu(DDC)2 drug. Poly(lactide-co-glycolide) (PLGA) nanoparticles were used to trap disulfram and copper gluconate separately, the two types of drug loaded nanoparticles were injected in mesothelioma-bearing nude mice via intraperitoneal injection. The in vivo formation of Cu(DDC)2 complex was induced by disulfiram and Cu2+ released from PLGA nanoparticles. This strategy avoided many obstacles in the use of Cu(DDC)2 complex as chemotherapeutic and exhibited excellent anticancer activity to mesothelioma.
As a class of metal-free two-dimensional (2D) semiconductor materials, polymeric carbon nitrides have attracted wide attention recently due to its facile regulation of the molecular and electronic structures, availability in abundance and high stability. According to the different ratios of C and N atoms in the framework, a series of CxNy materials have been successfully synthesized by virtue of various precursors, which further triggers extensive investigations of broad applications ranging from sustainable photocatalytic reactions and highly sensitive optoelectronic biosensing. In view of topological structures on their electronic structures and material properties, the as-reported CxNy could be generally classified into two main categories with three- or six-bond-extending frameworks. Owing to the effective n→π* transition in most CxNy materials, the relative energy level of the lone-pair electrons on N atoms is high, which thus endows the materials with the capability of visible light absorption. Meanwhile, the different repeating units, bridging groups and defect sites of these two kinds of CxNy allow them to effectively drive a diverse of promising applications that require specific electronic, interfacial and geometric properties. This review paper aims to summarize the recent progress in topological structure design and the relevant electronic band structures and striking properties of CxNy materials. In the final part, we also discuss the existing challenges of CxNy and outlook the prospect possibilities.
The tumor microenvironment (TME) significantly influences cancer evolution and therapeutic efficacy. Targeting biofunctional molecules to the TME has long been appreciated as a means of raising local drug concentrations and reducing systemic toxicities. The booming nanotechnology field has realized the importance of cathepsin B to derive a variety of intelligent enzyme-responsive nanosized drug delivery systems (nanoDDS) to improve treatment responses and clinical outcomes. In this tutorial review, after introducing the molecular structure and physiological/pathological functions of cathepsin B, the outstanding achievements of cathepsin B-responsive nanoplatforms in the precise diagnosis, targeted therapy, and synergistic theranostics of malignant tumors are systematically described. Finally, the challenges of enzyme-substrate incompatibility, low diagnostic sensitivity, mass production and biocompatibility of multifunctional nanoDDS are considered in order to successfully promote them to clinical applications.
Drug-loaded micelles for oral administration are desired for its convenience, low cost and flexibility, but current designs rely on introducing pH responsiveness, leaving problems like drug leakage and low accuracy of targeted delivery un-solved. Herein, we reported an acid-resistant ROS-responsive hyperbranched polythioether which can self-assemble into micellar structure and pass through the gastrointestinal tract without leaking drugs. At the inflammatory lesions, the thioester bonds are oxidized to sulphone groups to significantly increase the hydrophilicity in response to accumulated ROS species and efficiently release the encapsulated drugs. Animal experiments, including the evaluation of bodyweight, colon length, MPO activity, spleen index, histology and quantitative reverse transcription PCR, evidenced that the drug-loaded micelles have improved therapeutic efficiency compared to bare drug administration for the treatment of DSS-induced colitis in mice. This study provides an example of oral administrated micellar system can be extended for the treatment of other intestinal tract diseases.
Magnetic nanoparticles (MNPs) have become a research hotspot and widely used in the biomedical field in recent decades due to their unique magnetic properties. This minireview summarizes the specific gene transfection of magnetic particles (magnetofection) during eversy dynamic process of gene delivery (gene binding, cellular uptake, endosomal escape, intracellular trafficking and in vivo targeting). Meanwhile, the synergistic biomedical application of magnetofection and the effects of MNPs have also been discussed, including magnetic resonance imaging (MRI), magnetic mediated hyperthermia (MMH), Fenton reaction and autophagy. Finally, the clinical prospect of magnetofection was briefly expected.
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