The combination of high atomic number and high oxidation state in U materials gives rise to both high X-ray attenuation efficiency and intense green luminescence originating from ligand-to-metal charge transfer. These two features suggest that U materials might act as superior X-ray scintillators, but this postulate has remained substantially untested. Now the first observation of intense X-ray scintillation in a uranyl-organic framework (SCU-9) that is observable by the naked eye is reported. Combining the advantage in minimizing the non-radiative relaxation during the X-ray excitation process over those of inorganic salts of uranium, SCU-9 exhibits a very efficient X-ray to green light luminescence conversion. The luminescence intensity shows an essentially linear correlation with the received X-ray intensity, and is comparable with that of commercially available CsI:Tl. SCU-9 possesses an improved X-ray attenuation efficiency (E>20 keV) as well as enhanced radiation resistance and decreased hygroscopy compared to CsI:Tl.

No abstract

Pillar[5]arenes, as a new intriguing class of calixarene analogues, were functionalized with ten diglycolamide (DGA) arms on both sides (rims) of the pillar framework and evaluated for their extraction behaviour towards Am(III) and Eu(III). These novel extractants exhibit excellent separation and extraction efficiency, suggesting its significant potential for nuclear waste remediation. Laser induced fluorescence experiments disclosed strong complexation of the trivalent metal ions with the pillararene-DGA ligands.

Cancer-associated fibroblasts (CAFs) are common components of the tumor-suppressive microenvironment, and are a major determinant of the poor outcome of therapeutic vaccination. In this study, we modified tumor cells to express the fibroblast activation protein (FAP), which is highly expressed by CAFs, to potentially improve whole-cell tumor vaccines by targeting both tumor cells and CAFs. Tumor cells were transfected with murine FAP plasmids bearing the cationic lipid DOTAP. Its antitumor effects were investigated in three established tumor models. Vaccination with tumor cells expressing FAP eliminated solid tumors and tumors resulting from hematogenous dissemination. This antitumor immune response was mediated by CD8+ T cells. Additionally, we found that CAFs were significantly reduced within the tumors. Furthermore, this vaccine enhanced the infiltration of CD8+ T lymphocytes, and suppressed the accumulation of immunosuppressive cells in the tumor microenvironment. Our results indicated that the FAP-modified whole-cell tumor vaccine induced strong antitumor immunity against both tumor cells and CAFs and reversed the immunosuppressive effects of tumors by decreasing the recruitment of immunosuppressive cells and enhancing the recruitment of effector T cells. This conclusion may have important implications for the clinical use of genetically modified tumor cells as cancer vaccines.

As an emerging type of actinide hybrid material, uranyl–rotaxane coordination polymers (URCPs) with new coordination patterns and topological structures are still desired. In this work, we propose a new strategy to construct URCPs by promoting the simultaneous coordination of both the wheel and axle moieties in pseudorotaxane linkers with metal nodes. Starting from a series of cucurbit[6]­uril (CB[6])-based pseudorotaxane ligands, CnBPCA@CB­[6] [CnBPCA = 1,1-(α,ω-diyl)­bis­[4-(ethoxycarbonyl)­pyridin-1-ium] bromides, where n = 5–8] with slightly deformed CB[6], four new URCPs (URCP1, URCP3, URCP4, and URCP5) with interwoven network structures, as well as another noninterwoven polymer­(URCP2), have been successfully prepared. According to single-crystal structure analysis, we attribute the interwoven structures of the URCPs to the distortion of CB[6] in pseudorotaxane ligands with shorter or longer spacers (C5, C7, and C8). This indicates that the deformation could effectively diminish the steric hindrance around the portals, thus endowing the “inert” CB[6] host with coordination ability like the string molecule. Besides, the participation of water molecules and sulfate anions in the uranyl coordination sphere is also found to have a great influence on the final structures of the obtained URCPs. The successful preparation of interwoven URCPs in this work gives some new insights into the metal coordination of supramolecular entities and could facilitate other new applications of CB[6]-based pseudorotaxane ligands. Most importantly, the strategy proposed in this work provides some hints in the controllable design of metal–organic rotaxane frameworks with unique topologies.

This work targeted a molecular level of understanding on the dynamics of humic acid (HA) and its interaction with uranyl in the presence of hydrophobic surface mimicked by a carbon nanotube (CNT), which also represents a potential intruder in the environment accompanying with the development of nanotechnology. In aqueous phase, uranyl and HA were observed to build close contact spontaneously, driven by electrostatic interaction, leading to a more compact conformation of HA. The presence of CNT unfolds HA via π-π interactions with the aromatic rings of HA without significant perturbation on the interaction strength between HA and uranyl. These results show that the hydrophilic uranyl and the hydrophobic CNT influence the folding behavior of HA in distinct manners, which represents two fundamental mechanisms that the folding behavior of HA may be modulated in the environment, that is, uranyl enhances the folding of HA via electrostatic interactions, whereas CNT impedes its spontaneous folding via van der Waals (vdW) interactions. The work also provides molecular level of evidence on the transformation of a hydrophobic surface into a hydrophilic one via noncovalent functionalization by HA, which in turn affects the migration of HA and the cations it binds to.

No abstract

A novelly-defined adsorption membrane for rapid removal of fluoride from drinking water was prepared. Both zirconium metal-organic frameworks (Zr-MOFs) adsorbent and membrane with large specific surface area of 740.28m/g were used for fluoride removal for the first time. For adsorption technique, fluoride adsorption on Zr-MOFs was studied on a batch mode. The adsorption data could be well described by Langmuir isotherm model while the adsorption kinetic followed pseudo-second-order model. The maximum of adsorption capacity was 102.40mg/g at pH 7.0 when the initial fluoride concentration was 200mg/L. The FT-IR and XPS analyses of Zr-MOFs revealed that both surface hydroxyl groups and Zr(IV) active sites played important roles in fluoride adsorption process. The as-prepared Zr-MOFs adsorbent was suitable for practical treatment of drinking water and regeneration by sodium hydroxide solution (3wt%). For membrane experiments, Zr-MOFs membrane supported on Alumina substrate could remove fluoride efficiently through dynamic filtration. The fluoride removal capability of Zr-MOFs membrane depended on flow rate and initial concentration of fluoride. The fluoride removal abilities of Zr-MOFs membrane with 20μm thickness could reach 5510, 5173, and 4664L/m when fluoride concentrations were 5, 8 and 10mg/L, respectively. This study indicated that Zr-MOFs membrane could be developed into a very viable technology for highly effective removal of fluoride from drinking water.