Tiangong University

This work demonstrated that ultrasmall gold nanoparticles (AuNPs) smaller than 10 nm display unique advantages over nanoparticles larger than 10 nm in terms of localization to, and penetration of, breast cancer cells, multicellular tumor spheroids, and tumors in mice. Au@tiopronin nanoparticles that have tunable sizes from 2 to 15 nm with identical surface coatings of tiopronin and charge were successfully prepared. For monolayer cells, the smaller the Au@tiopronin NPs, the more AuNPs found in each cell. In addition, the accumulation of Au NPs in the ex vivo tumor model was size-dependent: smaller AuNPs were able to penetrate deeply into tumor spheroids, whereas 15 nm nanoparticles were not. Owing to their ultrasmall nanostructure, 2 and 6 nm nanoparticles showed high levels of accumulation in tumor tissue in mice after a single intravenous injection. Surprisingly, both 2 and 6 nm Au@tiopronin nanoparticles were distributed throughout the cytoplasm and nucleus of cancer cells in vitro and in vivo, whereas 15 nm Au@tiopronin nanoparticles were found only in the cytoplasm, where they formed aggregates. The ex vivo multicellular spheroid proved to be a good model to simulate in vivo tumor tissue and evaluate nanoparticle penetration behavior. This work gives important insights into the design and functionalization of nanoparticles to achieve high levels of accumulation in tumors.

Abstract Current technologies for removing heavy metal ions are typically metal ion specific. Herein we report the development of a broad-spectrum heavy metal ion trap by incorporation of ethylenediaminetetraacetic acid into a robust metal-organic framework. The capture experiments for a total of 22 heavy metal ions, covering hard, soft, and borderline Lewis metal ions, show that the trap is very effective, with removal efficiencies of >99% for single-component adsorption, multi-component adsorption, or in breakthrough processes. The material can also serve as a host for metal ion loading with arbitrary selections of metal ion amounts/types with a controllable uptake ratio to prepare well-dispersed single or multiple metal catalysts. This is supported by the excellent performance of the prepared Pd 2+ -loaded composite toward the Suzuki coupling reaction. This work proposes a versatile heavy metal ion trap that may find applications in the fields of separation and catalysis.

This paper proposes a novel sliding-mode observer (SMO) to achieve the sensorless control of permanent-magnet synchronous motor (PMSM). An observer is built according to the back electromotive force (EMF) model after the back EMF equivalent signal is obtained. In this way, not only are low-pass filter and phase compensation module eliminated, but also estimation accuracy is improved. Numerical simulations and experiments with an 11-kW low-speed PMSM are carried out. The results demonstrate that the novel SMO can effectively estimate rotor position and speed and achieve good static and dynamic performance.

Polyvinylidene fluoride (PVDF)–oxidized carbon nanotubes (OMWCNTs), PVDF–graphene oxide (GO) and PVDF–OMWCNTs–GO composite ultrafiltration membranes were prepared by solution-blending the ternary mixture of PVDF–oxidized low-dimensional carbon nanomaterials–dimethylacetamide in combination with the phase inversion method. The microscope images of the PVDF matrix microstructure showed that the composite membranes exhibited a bigger mean pore size and higher roughness parameters than pristine membranes. The contact angle of the membranes decreased from 78.5° (PVDF) to 66.8° (PVDF–OMWCNTs), 66.4° (PVDF–GO) and 48.5° (PVDF–OMWCNTs–GO). For the PVDF–OMWCNTs, PVDF–GO and PVDF–OMWCNTs–GO composite membranes, there was a 99.33%, 173.03% and 240.03% increase in permeation flux and a 21.71%, 17.23% and 14.29% increase in bovine serum albumin (BSA) rejection, respectively, compared with those of the pristine membranes. The newly developed composite ultrafiltration membranes demonstrate an impressive prospect for the anti-irreversible fouling performance in multi-cycle operations from BSA treatment. Additionally, the addition of OMWCNTs and GO increased the tensile strength of composite membranes from 1.866 MPa to 2.106 MPa and 2.686 MPa, respectively. Conspicuously, the PVDF composite ultrafiltration membranes endowed with oxidized low-dimensional carbon nanomaterials demonstrated fascinating hydrophilicity, permeability, antifouling and mechanical performance and promising application prospects owing to the rich oxygen-containing functional groups, high specific surface and synergistic effect of inorganic additive.

Abstract Proton exchange membranes with short-pathway through-plane orientated proton conductivity are highly desirable for use in proton exchange membrane fuel cells. Magnetic field is utilized to create oriented structure in proton exchange membranes. Previously, this has only been carried out by proton nonconductive metal oxide-based fillers. Here, under a strong magnetic field, a proton-conducting paramagnetic complex based on ferrocyanide-coordinated polymer and phosphotungstic acid is used to prepare composite membranes with highly conductive through-plane-aligned proton channels. Gratifyingly, this strategy simultaneously overcomes the high water-solubility of phosphotungstic acid in composite membranes, thereby preventing its leaching and the subsequent loss of membrane conductivity. The ferrocyanide groups in the coordinated polymer, via redox cycle, can continuously consume free radicals, thus helping to improve the long-term in situ membrane durability. The composite membranes exhibit outstanding proton conductivity, fuel cell performance and durability, compared with other types of hydrocarbon membranes and industry standard Nafion ® 212.

Substrate–molecule vibronic coupling enhancement, especially the efficient photoinduced charge transfer (PICT), is pivotal to the performance of nonmetal surface-enhanced Raman scattering (SERS) technology. Here, through developing novel two-dimensional (2D) amorphous TiO2 nanosheets (a-TiO2 NSs), we successfully obtained an ultrahigh enhancement factor of 1.86 × 106. Utilizing the Kelvin probe force microscopy (KPFM) technology, we found that these 2D a-TiO2 NSs possessed more positive surface potential than their 2D crystalline counterpart (c-TiO2 NSs). First-principles density functional theory (DFT) was used to further reveal that the low coordination number of surface Ti atoms and the large amount of surface oxygen defects endowed the 2D a-TiO2 with high electrostatic potential, which allowed significant charge transfer from the adsorbed molecule to the 2D a-TiO2 and facilitated the formation of a stable surface charge-transfer (CT) complex. Significantly, comparing with the 2D c-TiO2, the smaller band gap and higher electronic density of states (DOS) of the 2D a-TiO2 effectively enhanced the vibronic coupling of resonances in the substrate–molecule system. The strong vibronic coupling within the CT complex obviously enhanced the PICT resonance and lead to the remarkable SERS activity of a-TiO2 NSs. To the best of our knowledge, this is the first report on the remarkable SERS activity of 2D amorphous semiconductor nanomaterials, which may bring the cutting edge of development of stable and highly sensitive nonmetal SERS technology.

Lung cancer is the most common cancer that cannot be ignored and cause death with late health care. Currently, CT can be used to help doctors detect the lung cancer in the early stages. In many cases, the diagnosis of identifying the lung cancer depends on the experience of doctors, which may ignore some patients and cause some problems. Deep learning has been proved as a popular and powerful method in many medical imaging diagnosis areas. In this paper, three types of deep neural networks (e.g., CNN, DNN, and SAE) are designed for lung cancer calcification. Those networks are applied to the CT image classification task with some modification for the benign and malignant lung nodules. Those networks were evaluated on the LIDC-IDRI database. The experimental results show that the CNN network archived the best performance with an accuracy of 84.15%, sensitivity of 83.96%, and specificity of 84.32%, which has the best result among the three networks.

Finite-control-set model-predictive control (FCS-MPC) requires a large amount of calculation, which is an obstacle for its application. However, compared with the classical linear control algorithm, FCS-MPC requires a shorter control loop cycle time to reach the same control performance. To resolve this contradiction, this paper presents an effective method to simplify the conventional FCS-MPC. With equivalent transformation and specialized sector distribution method, the computation load of FCS-MPC is greatly reduced while the control performance is not affected. The proposed method can be used in various circuit topologies and cases with multiple constraints. Experiments on two-level converter and three-level NPC converter verify the good performance and application value of the proposed method.

Design of tough hydrogels has made great progress in the past two decades. However, the synthetic tough gels are usually much softer than some biotissues (e.g., skins with modulus up to 100 MPa). Here we report a new class of ultrastiff and tough supramolecular hydrogels facilely prepared by copolymerization of methacrylic acid and methacrylamide. The gels with water content of approximately 50–70 wt % possessed remarkable mechanical properties, with Young's modulus of 2.3–217.3 MPa, tensile breaking stress of 1.2–8.3 MPa, breaking strain of 200–620%, and tearing fracture energy of 2.9–23.5 kJ/m2, superior to most existing hydrogels, especially in terms of modulus. Typical yielding and crazing were observed in the gel under tensile loading, indicating the forced elastic deformation of these hydrogels in a glassy state, as confirmed by dynamic mechanical analysis. The ultrahigh stiffness was attributed to the dense cross-linking and reduced segmental mobility caused by the robust intra- and interchain hydrogen bonds. Because of the dynamic nature of noncovalent bonds, these supramolecular gels also showed rate-dependent mechanical performances along with good shape memory and recyclability. This strategy should be applicable for other systems toward robust mechanical properties, versatile functionalities, and promising applications of hydrogel materials as structural elements.

Abstract Triggered by the endogenous chemical energy in the tumor microenvironment (TME), chemodynamic therapy (CDT) as an emerging non‐exogenous stimulant therapeutic modality has received increasing attention in recent years. The chemodynamic agents can convert internal hydrogen peroxide (H 2 O 2 ) into the lethal reactive oxygen species (ROS) hydroxyl radicals ( • OH) for oncotherapy. Compared with other therapeutic modalities, CDT possesses many notable advantages, such as tumor‐specific, highly selective, fewer systemic side effects, and no need for external stimulation. Nevertheless, mild acid pH, low H 2 O 2 content, and overexpressed reducing substance in TME severely suppressed the CDT efficiency. With the rapid development of nanotechnology, some kinds of nanomaterials have been utilized with improved CDT efficiency. In particular, the excellent photo‐, ultrasound‐, magnetic‐, and other stimuli‐response properties of nanomaterials make it possible for combination cancer therapy of CDT with other therapeutic modalities, and it has shown superior anti‐cancer activity than monotherapies. Therefore, it is necessary to summarize the application of nanomaterial‐based chemodynamic cancer therapy. In this review, the various nanomaterials‐based nanoplatforms for CDT and its combinational therapies are summarized and discussed, aiming to provide inspiration for the design of better‐quality agents to promote the CDT development and lay the foundation for its future conversion to clinical applications.

The research and development of advanced energy-storage systems must meet a large number of requirements, including high energy density, natural abundance of the raw material, low cost and environmental friendliness, and particularly reasonable safety. As the demands of high-performance batteries are continuously increasing, with large-scale energy storage systems and electric mobility equipment, lithium–sulfur batteries have become an attractive candidate for the new generation of high-performance batteries due to their high theoretical capacity (1675 mA h g−1) and energy density (2600 Wh kg−1). However, rapid capacity attenuation with poor cycle and rate performances make the batteries far from ideal with respect to real commercial applications. Outstanding breakthroughs and achievements have been made to alleviate these problems in the past ten years. This paper presents an overview of recent advances in lithium–sulfur battery research. We cover the research and development to date on various components of lithium–sulfur batteries, including cathodes, binders, separators, electrolytes, anodes, collectors, and some novel cell configurations. The current trends in materials selection for batteries are reviewed and various choices of cathode, binder, electrolyte, separator, anode, and collector materials are discussed. The current challenges associated with the use of batteries and their materials selection are listed and future perspectives for this class of battery are also discussed.

A zwitterionic additive ( l -CN) with a positively charged quaternary ammonium site and multifunctional polar groups was employed to achieve ultralong-life Zn-ion batteries.

Idiopathic generalized epilepsy (IGE) has been linked with disrupted intra-network connectivity of multiple resting-state networks (RSNs); however, whether impairment is present in inter-network interactions between RSNs, remains largely unclear. Here, 50 patients with IGE characterized by generalized tonic-clonic seizures (GTCS) and 50 demographically matched healthy controls underwent resting-state fMRI scans. A dynamic method was implemented to investigate functional network connectivity (FNC) in patients with IGE-GTCS. Specifically, independent component analysis was first carried out to extract RSNs, and then sliding window correlation approach was employed to obtain dynamic FNC patterns. Finally, k-mean clustering was performed to characterize six discrete functional connectivity states, and state analysis was conducted to explore the potential alterations in FNC and other dynamic metrics. Our results revealed that state-specific FNC disruptions were observed in IGE-GTCS and the majority of aberrant functional connectivity manifested itself in default mode network. In addition, temporal metrics derived from state transition vectors were altered in patients including the total number of transitions across states and the mean dwell time, the fraction of time spent and the number of subjects in specific FNC state. Furthermore, the alterations were significantly correlated with disease duration and seizure frequency. It was also found that dynamic FNC could distinguish patients with IGE-GTCS from controls with an accuracy of 77.91% (P < 0.001). Taken together, this study not only provided novel insights into the pathophysiological mechanisms of IGE-GTCS but also suggested that the dynamic FNC analysis was a promising avenue to deepen our understanding of this disease. Hum Brain Mapp 38:957-973, 2017. © 2016 Wiley Periodicals, Inc.

Abstract The development of highly efficient metal‐free carbon electrocatalysts for the oxygen reduction reaction (ORR) is one very promising strategy for the exploitation and commercialization of renewable and clean energy, but this still remains a significant challenge. Herein, we demonstrate a facile approach to prepare three‐dimensional (3D) N‐doped carbon with a sp 3 /sp 2 carbon interface derived from ionic liquids via a simple pyrolysis process. The tunable hybrid sp 3 and sp 2 carbon composition and pore structures stem from the transformation of ionic liquids to polymerized organics and introduction of a Co metal salt. Through tuning both composition and pores, the 3D N‐doped nanocarbon with a high sp 3 /sp 2 carbon ratio on the surface exhibits a superior electrocatalytic performance for the ORR compared to that of the commercial Pt/C in Zn–air batteries. Density functional theory calculations suggest that the improved ORR performance can be ascribed to the existence of N dopants at the sp 3 /sp 2 carbon interface, which can lower the theoretical overpotential of the ORR.

A microporous three-dimensional (3D) hydrogen-bonded organic framework (HOF-20) has been constructed from an aromatic-rich tetratopic carboxylic acid, 5-(2,6-bis(4-carboxyphenyl)pyridin-4-yl)isophthalic acid (H4BCPIA). The activated HOF-20a has a moderately high Brunauer–Emmett–Teller (BET) surface area of 1323 m2 g–1 and excellent stability in water and HCl aqueous solution. HOF-20 exhibits highly efficient turn-up fluorescent sensing of aniline in water with a detection limit of 2.24 μM and is selective toward aniline in the presence of aromatic interferents, owing to the hydrogen bonding and edge-to-face π–π stacking interactions between the HOF-20 host and the guest aniline molecules, as demonstrated in the single-crystal X-ray structure of HOF-20⊃aniline. Density functional theory (DFT) calculations further demonstrate that the recognition of aniline molecules by HOF-20 could restrict the rotation of the aromatic rings in H4BCPIA linkers, reducing the nonradiative decay pathways upon photoexcitation and subsequently enhancing the fluorescence intensity.

Millions of tonnes of plastics have been released into the environment. Although the risk of plastics to humans is not yet resolved, microplastics, in the range of 1 μm - 5 mm, have entered our bodies, originating either from ingestion via the food chain or from inhalation of air. Generally there are two sources of microplastics, either directly from industry, such as cosmetic exfoliants, or indirectly from physical, chemical and biological fragmentation of large (>5 mm) plastic residues. We have found that microplastics can be generated by simple tasks in our daily lives such as by scissoring with scissors, tearing with hands, cutting with knives or twisting manually, to open plastics containers/bags/tapes/caps. These processes can generate about 0.46-250 microplastic/cm. This amount is dependent on the conditions such as stiffness, thickness, anisotropy, the density of plastic materials and the size of microplastics.This finding sends an important warning, that we must be careful when opening plastic packaging, if we are concerned about microplastics and care about reducing microplastics contamination.

Nanoparticles offer potential as drug delivery systems for chemotherapeutics based on certain advantages of molecular drugs. In this study, we report that particle size exerts great influence on the penetration and retention behavior of nanoparticles entering tumors. On comparing gold-coated Au@tiopronin nanoparticles that were prepared with identical coating and surface properties, we found that 50 nanoparticles were more effective in all in vitro, ex vivo, and in vivo assays conducted using MCF-7 breast cells as a model system. Beyond superior penetration in cultured cell monolayers, 50 nm Au@tiopronin nanoparticles also penetrated more deeply into tumor spheroids ex vivo and accumulated more effectively in tumor xenografts in vivo after a single intravenous dose. In contrast, larger gold-coated nanoparticles were primarily localized in the periphery of the tumor spheroid and around blood vessels, hindering deep penetration into tumors. We found multicellular spheroids to offer a simple ex vivo tumor model to simulate tumor tissue for screening the nanoparticle penetration behavior. Taken together, our findings define an optimal smaller size for nanoparticles that maximizes their effective accumulation in tumor tissue.

A green recycling process was designed and used to recycle spent LiCoO₂ batteries, and the recycled LiCoO₂ was regenerated after the solid state synthesis with Li₂CO₃.

A triple-layered TFC nanofiltration (NF) membrane consisting of a polyamide (PA) top layer covered on a poly(ether sulfone) microfiltration membrane with a carbon nanotube (CNT) interlayer was fabricated via interfacial polymerization. The structure and properties of the PA active layer could be finely tailored by tuning the interfacial properties and pore structure of the CNT interlayer, including its surface pore size and thickness, thus improving its NF performance. This TFC NF membrane exhibited a high divalent salt rejection (the rejection of Na2SO4 and MgSO4 solution >98.3%) and dye rejection (the rejection of methyl violet (MV) >99.5%) with a high pure water flux of around 21 L m–2 h–1 bar–1. Excitingly, this membrane also showed excellent selectivity to both mono/divalent salt ion (the selectivity of Cl–/SO42– is as high as 85.5) and NaCl/dye solution (the selectivity of NaCl/MV is more than 123.5), which are much higher than most of other commercial and reported NF membranes. Moreover, this membrane also showed a good separation performance and long-term stability during a continuous NF process for a salt/dye mixture solution. This triple-layered TFC NF membrane showed a great promise for applications in both wastewater treatment and dyes recycling.

The catalytic transfer hydrogenation (CTH) reaction is considered as a potential route for upgrading bio-based carbonyls to their corresponding alcohols. Herein, a series of Zr-based metal−organic frameworks (Zr-MOFs) containing various types of metal node to ligand coordinations were synthesized and tested for CTH of furfural (FUR) to furfuryl alcohol (FOL). It was found that metal node coordination plays a more important role than porosity in Zr-MOFs. MOF-808 (synthesized using a scaled-up approach to achieve a higher batch yield), with the lowest metal node to ligand coordination (coordination number 6), was found to be the most active catalyst among the various tested Zr-MOFs. Furthermore, M-MOF-808, modified by simple methanol activation (M), outperformed the pristine MOF-808 in CTH of FUR to FOL even at 30 °C in the presence of 2-propanol (IPA) as the hydrogen source. The simple modification of the metal node in the Zr-MOF changed the acid–base properties of the MOF-808 surface through the development of coordinatively unsaturated sites (CUS), hydroxyl and methoxy groups in the framework of the Zr-MOF, which probably help to facilitate the adsorption of FUR and IPA onto the metal node surfaces of the catalyst. To evaluate the versatility of methanol activation in CTH, further substrates, including other types of biomass and representative carbonyl compounds over M-MOF-808, were tested. To demonstrate heterogeneous catalysis, the catalyst was recycled for five consecutive cycles, with little loss after the first cycle, and was fully characterized to observe any changes in its structure. Mechanistic insights were provided by isotopically labeled 2-propanol-d8 experiments, indicating FUR reduction through transfer hydrogenation. Finally, the reaction mechanism for CTH of FUR to FOL was proposed in detail using density functional theory (DFT) calculations over metal node modified model systems of a 6-connected Zr-MOF.