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Caries as a result of acid demineralization is the most common oral microbial infectious disease. Due to the small and complex intraoral operating space, it is challenging to completely remove Streptococcus mutans (S. mutans) and other cariogenic bacteria. As an intelligent acid-responsive photosensitive nanomaterial, O2-Cu/ZIF-8@Ce6/ZIF-8@HA (OCZCH) was chosen to adapt to the anaerobic and acidic microenvironment for inactivating S. mutans. In this work, OCZCH not only exhibits a regular nanomorphology in SEM and TEM images but also shows intelligent acid responsiveness as evidenced by the release of Ce6 and oxygen. When excited by near-infrared light at 650 nm, Ce6 releases reactive oxygen species (ROS) that act synergistically with internal oxygen to significantly enhance the antimicrobial therapeutic effect of photodynamic therapy (PDT). In vitro antimicrobial experiments showed that OCZCH could achieve an impressive sterilization effect against S. mutans and biofilm. Notably, the acid-producing ability of the bacteria was also significantly inhibited. With its oxygen-carrying photosensitizing properties, excellent responsiveness to acidic environments, and antimicrobial capacity under anaerobic conditions, OCZCH is considered an innovative candidate for clinical application in treating dental caries. [ABSTRACT FROM AUTHOR]

Based on the confinement effect of metal–organic frameworks (MOFs), a new and straightforward method for synthesizing unsymmetrically substituted NH-pyrroles from α-hydroxyketone and 3-aminocrotonate was developed. The confined space of the pore channels limited the potential overreaction, allowing for good control of the reaction selectivity, compared to the corresponding homogeneous catalysts that barely control the overreaction. The synthesis of NH-pyrroles using this route also provides a new strategy for the utilization of bio-based platform molecules, such as α-hydroxyketones. [ABSTRACT FROM AUTHOR]

Exploration of highly selective catalysts for CO2 hydrogenation remains a great challenge since the reduction of CO2 over the supported metal catalysts may give rise to various products in response to the modulation of the chemical state of active sites. Herein, by varying the pretreatment temperature of iridium/titanium oxide (Ir/TiO2) catalysts, the selectivity of CO2 hydrogenation from CH4 to sole production of CO can be finely tuned. The change of product selectivity is achieved in such a way that the selectivity greatly depend on the formation of a reduced TiOx overlayer around Ir nanoparticles (NPs) as originated from the strong metal–support interaction (SMSI). With only a weak reduction treatment, the exposed Ir NPs without a TiOx coating promote CH4 production exclusively. After the catalyst undergoes a high temperature reduction, the evolution of the TiOx coating over Ir NPs shows a preference for CO production with an inhibition of further methanation. This study not only provides insights into the regulation of CO2 hydrogenation by SMSI, but also serves as an effective approach to tuning other catalytic processes. [ABSTRACT FROM AUTHOR]

The development of upconversion luminescence that allows for multimodal imaging in terms of resolution and penetration depth using a single system is attracting increasing interest for use in clinical molecular imaging and diagnostics. In this study, a simple method for inducing high-intensity upconversion luminescence by doping Li+ ions in a core–shell-structured NaLuF4:Yb,Tm system was developed. The synergistic effects of Li+ doping and the shell layer enhanced the luminescence intensity by approximately 210 times. In vitro and in vivo experiments showed that the high-intensity luminescence of nanoparticles exhibited a depth penetration ability for biological tissue. Owing to the heavy atom effect of the Lu3+ ions, the nanoparticles, which had a size of 23 nm, showed good CT imaging performance when compared with a clinical contrast agent, in addition to allowing for deep tissue imaging. The excellent optical and CT imaging properties of the Li+-doped high-luminescence core–shell upconversion nanoparticles suggest that they are highly suited for use in both deep tissue fluorescence imaging and CT imaging for multimodal diagnosis. [ABSTRACT FROM AUTHOR]

Novel catalytic material with high catalytic activity and hydrothermal stability plays a key role in the efficient conversion of levulinic acid (LA) to γ-valerolactone (GVL) in water. In this study, mixed oxides Al 2 O 3 -TiO 2 , Al 2 O 3 -MoO 3 and Al 2 O 3 -Co 3 O 4 were synthesized by co-precipitation using aqueous solution of NaOH as precipitant. Ru catalysts supported on mixed oxides were prepared by impregnation method and their catalytic performances were tested in the hydrogenation of LA to GVL on a fixed bed reactor. The physicochemical properties of the catalysts were characterized by XRD, H 2 -TPR, NH 3 -TPD, and BET techniques. The TiO 2 component significantly affected the acidity of the catalyst, and thus its catalytic activity for the GVL yield was affected. The desired product GVL with a yield of about 97% was obtained over the Ru/Al 2 O 3 -TiO 2 catalyst under mild conditions (WHSV = 1.8 h -1 , T = 80 °C). Moreover, the catalyst Ru/Al 2 O 3 -TiO 2 exhibited excellent thermal stability in the test period of time., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The development of upconversion luminescence that allows for multimodal imaging in terms of resolution and penetration depth using a single system is attracting increasing interest for use in clinical molecular imaging and diagnostics. In this study, a simple method for inducing high-intensity upconversion luminescence by doping Li + ions in a core-shell-structured NaLuF 4 :Yb,Tm system was developed. The synergistic effects of Li + doping and the shell layer enhanced the luminescence intensity by approximately 210 times. In vitro and in vivo experiments showed that the high-intensity luminescence of nanoparticles exhibited a depth penetration ability for biological tissue. Owing to the heavy atom effect of the Lu 3+ ions, the nanoparticles, which had a size of 23 nm, showed good CT imaging performance when compared with a clinical contrast agent, in addition to allowing for deep tissue imaging. The excellent optical and CT imaging properties of the Li + -doped high-luminescence core-shell upconversion nanoparticles suggest that they are highly suited for use in both deep tissue fluorescence imaging and CT imaging for multimodal diagnosis.