Plasmonic coupling-enhanced in situ photothermal nanoreactor with shape selective catalysis for C-C coupling reaction

Carbon-carbon (C-C) coupling reactions represent one of the most powerful tools for the synthesis of complex natural products, bioactive molecules developed as drugs and agrochemicals. In this work, a multifunctional nanoreactor for C-C coupling reaction was successfully fabricated via encapsulating the core-shell Cu@Ni nanocubes into ZIF-8 (Cu@Ni@ZIF-8). In this nanoreactor, Ni shell of the core-shell Cu@Ni nanocubes was the catalytical active center, and Cu core was in situ heating source for the catalyst by absorbing the visible light. Moreover, benefiting from the plasmonic resonance effect between Cu@Ni nanocubes encapsulated in ZIF-8, the absorption range of nanoreactor was widened and the utilization rate of visible light was enhanced. Most importantly, the microporous structure of ZIF-8 provided shape-selective of reactant. This composite was used for the highly shape-selective and stable photocatalysed C-C coupling reaction of boric acid under visible light irradiation. After five cycles, the nanoreactor still remained high catalytical activity. This Cu@Ni@ZIF-8 nanoreactor opens a way for photocatalytic C-C coupling reactions with shape-selectivity.

     

The influence of carbon materials on the absorption performance of polymer-derived SiCN ceramics in X-band

Carbon-containing polymer-derived SiCN ceramics (PDCs-SiCN-C) were successfully fabricated with multi-layer graphene (MLG) and multiwalled carbon nanotubes (MWCNTs) as additives at 1100?°C. The effects of MLG and MWCNTs on the microwave absorption properties of PDCs-SiCN-C ceramics were analyzed. The imaginary permittivity and loss tangent of SiCN-MLG and SiCN-MWCNTs were about 3.4, 0.67 at 11.2?GHz and 3.1, 0.57 at 10.6?GHz, respectively. The minimum reflection loss of SiCN-MLG and SiCN-MWCNTs at 3?mm was ??54?dB and ??48?dB with the effective absorption bandwidth (RL ≤ ?10?dB, >90% absorption) about 1.5?GHz and 0.9?GHz in X-band.     

A preliminary study on the preparation of nanostructured Ti-doped Li4SiO4 pebbles by two-step sintering process

Li₄SiO₄ has been widely studied as attractive tritium breeding materials due to its innate merits. Considering the potential advantages of nanostructure in tritium breeding materials, a distinctive process was developed to obtain nanostructured Li₄SiO₄ pebbles. In brief, ultrafine precursor powders were synthesized by solvothermal method without using surfactants, and then indirect wet method was adopted to generate the green spheres with homogeneous microstructure. After that, the suitable sintering conditions were defined by studying the effects of sintering parameters on the grain size evolution, and nanostructured Ti-doped Li₄SiO₄ pebbles were first obtained by two-step sintering method. This study will be expected to provide references for fabricating other Li-based tritium breeding materials.     

微覆盖解决高低层混合居民楼深度覆盖的应用

城区高低层混合居民楼区域作为无线网络覆盖难点,传统宏站无法进行有效的覆盖。本文通过采用“微覆盖、微对打”的建设方式有效解决“高低层混合居民楼”无线网络信号的深度覆盖问题。     

Association of solid fuel use with risk of stunting in children living in China

Stunting adversely affects physical and mental outcomes of children. It has not been examined whether household air pollution from solid fuel combustion is a risk factor for stunting in children. In a total of 41,439 children aged 6-17 across China, height was measured using a unified protocol. Multivariable linear regression models and logistic regression models were used to assess the associations of solid fuel use for cooking/heating with stunting in children. Adjusted for covariates, cooking/heating with solid fuel was significantly associated with a lower z-score for height for age and sex (β = −0.21 [−0.32 to −0.09] and −0.17 [−0.31 to −0.03], respectively) and an increased risk of stunting with an estimated ORs of 1.34 [1.07~1.68] and 1.37 [1.02~1.83], respectively. The risk of stunting associated with solid fuel use was statistically significant in high-age children. And the effect was greater on girls than on boys, though the difference was not statistically significant. Our study suggested that Chinese children living in households using solid fuel had a significantly higher risk of stunting than those living in households using cleaner fuel.     

Nanomaterials for radiotherapeutics-based multimodal synergistic cancer therapy

Over the past decade, numerous studies have attempted to enhance the effectiveness of radiotherapy (external beam radiotherapy and internal radioisotope therapy) for cancer treatment. However, the low radiation absorption coefficient and radiation resistance of tumors remain major critical challenges for radiotherapy in the clinic. With the development of nanomedicine, nanomaterials in combination with radiotherapy offer the possibility to improve the efficiency of radiotherapy in tumors. Nanomaterials act not only as radiosensitizers to enhance radiation energy, but also as nanocarriers to deliver therapeutic units in combating radiation resistance. In this review, we discuss opportunities for a synergistic cancer therapy by combining radiotherapy based on nanomaterials designed for chemotherapy, photodynamic therapy, photothermal therapy, gas therapy, genetic therapy, and immunotherapy. We highlight how nanomaterials can be utilized to amplify antitumor radiation responses and describe cooperative enhancement interactions among these synergistic therapies. Moreover, the potential challenges and future prospects of radio-based nanomedicine to maximize their synergistic efficiency for cancer treatment are identified.

     

Utilization of bio‐sourced myrcene for efficient preparation of highly cis‐1,4 regular elastomer via a neodymium catalyzed copolymerization strategy

The depletion of fossil based chemicals and the associated pollution have presented huge challenges to sustainability. In this study, we report on bio‐available myrcene participating in copolymerization with isoprene and butadiene by using neodymium catalysts without disruption of the pristine polymer's properties. Efficient incorporation of myrcene into the copolymer was achieved with slightly retarded reactivity compared to the reactivities of butadiene and isoprene. Copolymerization of myrcene with hydroxyl myrcene still remained compatible with the catalyst systems when the cocatalyst was fed in excess, resulting in a novel type of full myrcene based functional elastomer. The high cis‐1,4 selectivity of the system maintained the same level as the homopolymerization. Significant affinity to polar substances was deduced from the remarkably reduced water contact angle, a strong indication of good compatibility with reinforcing fillers. All copolymers displayed over 93.2% cis‐1,4 regularity and high molecular weight with narrow ?. Good resistance to low temperature was also achieved as indicated by the low glass transition temperature for all copolymers. This study verified that myrcene can be used as a sustainable monomer substituent for general diene based elastomer preparation. © 2020 Society of Chemical Industry