Always positive covalent organic nanosheet enabling pH-independent adsorption and removal of Cr(â ¥).

Rapid and highly effective removal of hexavalent chromium (Cr(Ⅵ)) is extremely vital to water resources restoration and environmental protection. To overcome the pH limitation faced by most ionic absorbents, an always positive covalent organic nanosheet (CON) material was prepared and its Cr(VI) adsorption and removal capability was investigated in detail. As-prepared EB-TFB CON (TFB = 1,3,5-benzaldehyde, EB = ethidium bromide) shows strong electropositivity in the tested pH range of 1 ∼ 10, display a pH-independent Cr(VI) removal ability, and work well for Cr(VI) pollution treatment with good anti-interference capability and reusability in a wide pH range covering almost all Cr(VI)-contaminated real water samples, thus eliminating the requirement for pH adjustment. Moreover, the nanosheet structure, which is obtained by a facile ultrasonic-assisted self-exfoliation, endows EB-TFB CON with fully exposed active sites and shortened mass transfer channels, and the Cr(VI) adsorption equilibrium can be reached within 15 min with a high adsorption capacity of 280.57 mg·g-1. The proposed Cr(VI) removal mechanism, which is attributed to the synergetic contributions of electrostatic adsorption, ion exchange and chemical reduction, is demonstrated by experiments and theoretical calculations. This work not only provides a general Cr(VI) absorbent without pH limitation, but also presents a paradigm to prepare ionic CONs with relatively constant surface charges.

DNA-Functionalized Porphyrinic Metal-Organic Framework-Based Drug Delivery System for Targeted Bimodal Cancer Therapy.

A DNA-functionalized porphyrinic MOF (porMOF) drug delivery system was successfully constructed. porMOF as a photosensitizer and drug delivery carrier can integrate photodynamic therapy (PDT) and chemotherapy. Via the strong coordination interaction between the zirconium cluster of porMOF and the terminal phosphate group of DNA, the stable modification of the DNA layer on the porMOF surface is achieved. Meanwhile, the introduction of C/G-rich base pairs into the DNA double-stranded structure provides more binding sites of chemotherapeutic drug doxorubicin (DOX). AS1411, an aptamer of nucleolin proteins that are overexpressed by cancer cells, is introduced in the double-stranded terminal, which can endow the nanosystem with the ability to selectively recognize cancer cells. C-rich sequences in DNA double strands form an i-motif structure under acidic conditions to promote the highly efficient release of DOX in cancer cells. In vitro and in vivo experiments demonstrate that the synergistic PDT/chemotherapy modality achieves highly efficient cancer cell killing and tumor ablation without undesirable side effects.

Telomerase-activated Au@DNA nanomachine for targeted chemo-photodynamic synergistic therapy.

We successfully designed a smart activatable nanomachine for cancer synergistic therapy. Photodynamic therapy (PDT) and chemotherapy can be activated by intracellular telomerase while anti-cancer drugs can be effectively transported into tumour cells. An Sgc8 aptamer was designed, which can specifically distinguish tumour cells from normal cells and perform targeted therapy. The nanomachine entered the tumour cells by recognising PTK7, which is overexpressed on the surface of cancer cells. Then, the "switch" of the system was opened by TP sequence extension under telomerase stimulus. So, the chemotherapeutic drug DOX was released to achieve the chemotherapy, and the Ce6 labelled Sgc8-apt was released to activate the PDT. It was found that if no telomerase existed, the Ce6 would always be in an "off" state and could not activate the PDT. Telomerase is the key to controlling the activation of the PDT, which effectively reduces the damage photosensitisers cause to normal cells. Using in vitro and in vivo experiments, the nanomachine shows an excellent performance in targeted synergistic therapy, which is expected to be utilised in the future.

Stable and oxidative charged Ru enhance the acidic oxygen evolution reaction activity in two-dimensional ruthenium-iridium oxide.

The oxygen evolution reactions in acid play an important role in multiple energy storage devices. The practical promising Ru-Ir based catalysts need both the stable high oxidation state of the Ru centers and the high stability of these Ru species. Here, we report stable and oxidative charged Ru in two-dimensional ruthenium-iridium oxide enhances the activity. The Ru0.5Ir0.5O2 catalyst shows high activity in acid with a low overpotential of 151 mV at 10 mA cm-2, a high turnover frequency of 6.84 s-1 at 1.44 V versus reversible hydrogen electrode and good stability (618.3 h operation). Ru0.5Ir0.5O2 catalysts can form more Ru active sites with high oxidation states at lower applied voltages after Ir incorporation, which is confirmed by the pulse voltage induced current method. Also, The X-ray absorption spectroscopy data shows that the Ru-O-Ir local structure in two-dimensional Ru0.5Ir0.5O2 solid solution improved the stability of these Ru centers.

Carbon emission reduction effects of intellectual property institution construction in China.

Institutions are the fundamental determinants of carbon emission performance. However, the environmental impact of intellectual property institution, especially its impact on carbon emissions, has been paid little attention. Therefore, the main purpose of this study is to assess the effect of intellectual property institution on carbon emission reduction, revealing a new solution to control carbon emissions. To achieve the goal, this study regards the National Intellectual Property Demonstration City (NIPDC) policy in China as a quasi-natural experiment of intellectual property institution construction and exploits the difference in difference approach to objectively evaluate the impact of intellectual property institution on carbon emission reduction based on the panel data of China's cities. The study draws the following important conclusions. First, compared with non-pilot cities, the NIPDC policy has reduced urban carbon emissions by 8.64% in pilot cities. In particular, the "carbon emission reduction dividend" of the NIPDC policy is in the long term but not in the short term. Second, the influence mechanism analysis shows that the NIPDC policy can promote carbon emission reduction by stimulating technology innovation, especially breakthrough innovation. Third, the space overflow analysis reveals that the NIPDC policy can mitigate carbon emissions in adjacent areas, resulting in obvious spatial radiation effect. Fourth, the heterogeneity analysis confirms that the carbon emission reduction effect of the NIPDC policy is more obvious in low administrative hierarchic cities, small and medium-sized cities, and western cities. As a result, Chinese policymakers should orderly promote the construction of NIPDCs, strengthen technology innovation, give full play to the spatial radiation role of NIPDCs, and optimize the role of government, so as to better release the carbon emission abatement effect of intellectual property institution.

The Key Effect of Carboxyl Group and CuN2 O2 Coordinate Structure for Cu, N Co-Doped Carbon Dots with Peroxidase-Like Property.

Carbon dots (CDs) with good water solubility and biocompatibility have become a research hotspot in the nano-enzyme and biomedical field. However, the problems of low catalytic activity and ambiguous catalytic site of CDs as nanozymes still need to be addressed. In this work, CDs loaded with Cu single atoms are obtained through pyrolysis, and the coordination structure and surface functional groups are regulated by adjusting the pyrolysis temperature. CDs obtained at 300 °C (named Cu-CDs-300) have the most carboxyl content and Cu is coordinated in the form of CuN2 O2 , which can better decompose H2 O2 to produce free radical and is beneficial to catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). The vmax is 6.56*10-7  m s-1 , 6.56 times higher than that of horseradish peroxidase (HRP). Moreover, Cu-CDs-300 can effectively lead to CT26 apoptosis by generating much free radicals. This work demonstrates the synergistic effect of oxygen-containing functional groups and metal coordination structures on peroxide-like activity of CDs and provides new ideas for the design of clear active structure and high efficiency peroxide-like single atom CDs catalyst.

Super-Branched PdCu Alloy for Efficiently Converting Carbon Dioxide to Carbon Monoxide.

The alloying of noble metals with Cu is one of the most effective strategies for improving catalytic performance and reducing cost in electrocatalytic carbon dioxide reduction reactions (CO2RR). Previous works usually focused on the influence of morphology and composition on the catalytic activity, but lacked the study of the valence state ratio of metals and the electron transfer behavior on alloys. In this work, PdCu-2 alloy (Pd/Cu molar ratio is 1:2) was obtained by a simple one-step solvothermal method, which can effectively convert CO2 to CO with a maximum Faradaic efficiency (FE) of 85% at -0.9 V (vs. RHE). Then, the effect of the chemical state of Pd and Cu on the catalytic performance was investigated. The X-ray photoelectron spectroscopy (XPS) shows that the binding energy of Pd in PdCu alloy has a negative shift, which has affected the adsorption of key intermediates. When the proportion of oxidized state and zero-valent metal in the alloy is about 1:2, the PdCu alloy shows the best catalytic activity. In addition, the transient photovoltage (TPV) measurements further demonstrate that due to the introduction of Cu, the electron transfer rate of PdCu-2 becomes the slowest, which helps the accumulation of electrons on PdCu-2 and leads to the improvement of catalytic performance for electrocatalytic CO2RR. This work can provide more insights into the alloy catalysts of electrocatalytic CO2RR.

Effects of phase-transited lysozyme on adhesion, migration and odontogenic differentiation of human dental pulp cells: An in vitro study.

AIM: To explore the effects of phase-transited lysozyme (PTL) coated dentine slices on cell adhesion, migration and odontogenic differentiation of human dental pulp cells (HDPCs). METHODOLOGY: Cell growth and cell cycle analysis were conducted to verify the biocompatibility of PTL for HDPCs. Cell adhesion, cell morphology and proliferation were explored by DiI staining, Scanning electron microscopy and MTT assay. Cell migration was investigated by Transwell assay. The effects of PTL on odontogenesis and mineralization of HDPCs were assessed by real-time quantitative polymerase chain reaction and Western blot. The mineralization of HDPCs was evaluated by Alizarin red staining. HDPCs were isolated from extracted third molars. The level of statistically significant difference was accepted at p < .05. RESULTS: PTL showed no negative effect on cell cycle of HDPCs and compared with the blank group, HDPCs labelled with DiI staining showed significantly more adhered cells at 48 h (p < .05), extending cell processes and more finger-like or reticular pseudopodia on PTL-coated dentine slices. The results of MTT and Transwell assay showed that PTL promoted the proliferation (p < .05) and migration (p < .01) of HDPCs, respectively. Compared with the blank group, the gene expression of dentine sialophosphoprotein (DSPP), osteopontin and bone sialoprotein in HDPCs cultured on PTL was significantly upregulated on day 3 and 7 (p < .05), while the protein expression of DSPP showed no significant change on both day 7 and day 14. Alizarin red staining showed that PTL promoted more mineralization nodules formation of HDPCs (p < .05). CONCLUSIONS: PTL promoted the adhesion, proliferation and migration of HDPCs on dentine slices, and positively affected odontogenic differentiation and mineralization of HDPCs.

Continuously Quantifying Oral Chemicals Based on Flexible Hybrid Electronics for Clinical Diagnosis and Pathogenetic Study.

Simultaneous monitoring of diverse salivary parameters can reveal underlying mechanisms of intraoral biological processes and offer profound insights into the evolution of oral diseases. However, conventional analytical devices with bulky volumes, rigid formats, and discrete sensing mechanisms deviate from the requirements of continuous biophysiological quantification, resulting in huge difficulty in precise clinical diagnosis and pathogenetic study. Here, we present a flexible hybrid electronic system integrated with functional nanomaterials to continuously sense Ca2+, pH, and temperature for wireless real-time oral health monitoring. The miniaturized system with an island-bridge structure that is designed specifically to fit the teeth is only 0.4 g in weight and 31.5 × 8.5 × 1.35 mm3 in dimension, allowing effective integration with customized dental braces and comfort attachment on teeth. Characterization results indicate high sensitivities of 30.3 and 60.6 mV/decade for Ca2+ and pH with low potential drifts. The system has been applied in clinical studies to conduct Ca2+ and pH mappings on carious teeth, biophysiological monitoring for up to 12 h, and outcome evaluation of dental restoration, providing quantitative data to assist in the diagnosis and understanding of oral diseases. Notably, caries risk assessment of 10 human subjects using the flexible system validates the important role of saliva buffering capacity in caries pathogenesis. The proposed flexible system may offer an open platform to carry diverse components to support both clinical diagnosis and treatment as well as fundamental research for oral diseases and induced systemic diseases.

ZIF/Co-C3N4 with enhanced electrocatalytic reduction of carbon dioxide activity by the photoactivation process.

Introducing the effect of light into an electrocatalytic system is an effective method to improve electrocatalytic carbon dioxide reduction (CO2RR). Here, the composite catalyst (ZIF/Co-C3N4) was prepared for the electrocatalytic reduction of carbon dioxide. The Faraday efficiency of the catalytic reduction of CO2 to CO under light could reach 90.34% at -0.67 V vs. the RHE (reversible hydrogen electrode), which was 30% higher than that obtained under darkness, and the overpotential was reduced by 200 mV. Chemical kinetics experiments and in-situ transient photovoltage (TPV) tests show that the reason for highly efficient CO2RR is intermediate CO2- formed by activated CO2 in the electrocatalytic system under light. This work offers a deep insight into the photo-activated electrocatalytic reduction of carbon dioxide, and also opens a new way to devise efficient catalysts for CO2RR.

Chiral Control of Carbon Dots via Surface Modification for Tuning the Enzymatic Activity of Glucose Oxidase.

Chiral carbon dots (CDs) integrated the advantages of achiral CDs and the unique chiral property, which expand the prospect of the biological applications of CDs. However, the structure control and the origin of chirality for chiral CDs remain unclear. Herein, chiral CDs were obtained by thermal polymerization of chiral amino acids and citric acid, and their handedness of chirality could be controlled by adjusting the reaction temperature, which leads to different kinds of surface modifications. With aliphatic amino acids as a chiral source, all of the CDs that reacted at different temperatures (90-200 °C) have the same handedness of the chiral source. But with aromatic amino acids as a chiral source, CDs with maintained or inversed handedness compared with the chiral source could be obtained by adjusting the reaction temperature. Below a temperature of 120 °C, the chiral source was modified with CDs by esterification and transferred the handedness of chirality; at high temperatures (above 150 °C), which mainly connected by amidation accompanying with the formation of rigid structure generated by the π conjugation between the aromatic nucleus of chiral source and the carbon core of CDs, caused the inversing of the chiral signal. Further, we investigated the chiral effects of CDs on the glucose oxidase activity for a highly sensitive electrochemical biosensor.

Carbon dot-modified mesoporous carbon as a supercapacitor with enhanced light-assisted capacitance.

A light-charging energy storage device is a promising approach of utilizing solar energy, and the reasonable design of light-assisted supercapacitors with photosensitive materials is one of the efficient ways to realize solar energy conversion and storage. Here, the electrode material (OPC-CDs-700) prepared by combining procanthocyanins with carbon dots (CDs) can reach the specific capacitance of 312 F g-1 at 0.1 A g-1 under visible light, which is an increase of 54.4% compared with that of under dark conditions. Besides, this light-assisted supercapacitor exhibits excellent cyclic stability after 4000 cycles. A series of electrochemical measurements show that CDs could stabilize the charge under light illumination due to its photoactivity, thus increasing the accumulation and storage of charge on the surface of OPC-CDs-700. This study provides new prospects for the progress of photosensitive energy devices and application of solar energy.

[Effect of miR-873 on cardiomyocyte apoptosis induced by hypoxia reoxygenation and its mechanism].

OBJECTIVE: To explore the role of miR-873 in cardiomyocyte injury induces by hypoxia reoxygenation (H/R) and its related mechanisms.
 Methods: H/R model was established by culturing mouse cardiac H9c2 cells in vitro, and miR-873 mimic was transfected. The experiments were divided into a control group, a H/R group, a negative control group and a miR-873 mimic group. The expression of miR-873 was measured using real-time PCR. The protein expression levels of egl-9 family hypoxia inducible factor 3 (Egln3), B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax) were evaluated by Western blotting. Cell apoptosis ELISA kit and cysteine-containing, aspartate-specific proteases-3 (caspase-3) activity kit was used to detect cell apoptosis and caspase-3 activity, respectively. The targeting effect of miR-873 on Egln3 were examined by the dual luciferase report gene assay, and the experiments were divided into a negative control group, a Egln3 3'-untranslated regions (3'-UTR) WT group (WT group) and a Egln3 3'-UTR MUT group (MUT group). In order to further detect the effects of Egln3 on miR-873 mimics, the Egln3 overexpressed cells were constructed, and the experiments were divided into a H/R group, a H/R+miR-873 mimic group, a H/R+pcDNA3-Egln3 (pcEgln3) group and a H/R+ miR-873 mimic+pcEgln3 group.
 Results: Compared with the control group, the expression level of miR-873 was significantly decreased in the H/R group (P<0.05). Compared with the H/R group, H9c2 cell apoptosis, caspase-3 activity and the ratio of Bax/Bcl-2 were significantly reduced in the miR-873 mimic group (all P<0.05). Compared with the negative control group, the luciferase activity was significantly down-regulated in the WT group (P<0.05), while the luciferase activity was not significantly changed in the MUT group (P>0.05). In the over-expression experiment, compared with the H/R group, the cell apoptosis and the ratio of Bax/Bcl-2 were significantly reduced in the miR-873 mimic group (both P<0.05). Compared with miR-873 mimic group, the cell apoptosis and the ratio of Bax/Bcl-2 were significantly up-regulated in the H/R+pcEgln3 group and the H/R+miR-873 mimic+pcEgln3 group (all P<0.05).
 Conclusion: MiR-873 can inhibit H/R- induced apoptosis of cardiomyocyte via targeting Egln3.

Carbon Defect-Induced Reversible Carbon-Oxygen Interfaces for Efficient Oxygen Reduction.

It is a great challenge to fabricate a metal-free oxygen reduction reaction (ORR) electrocatalyst that can operate well in the acidic medium and fuel cells system. Here, a metal-free carbon material C-900 with abundant defect sites is fabricated by a self-sacrificed template and a solid-state reaction strategy. C-900 shows a superior performance to 20% Pt/C in alkaline medium and a performance closer to 20% Pt/C in acidic condition. It can thus be applied in air-breathing fuel cell (without extra operation pressure) as the cathode catalyst, which shows a high performance (1160 W L-1; ∼62% of 20% Pt/C) with excellent stability. By using oxygen temperature-programmed desorption, the strong selective chemisorption of O2 on C-900 has been revealed. The excellent chemisorption property of C-900 may originate from the large amounts of carbon defect sites, which have been confirmed by synchrotron radiation-based X-ray absorption spectroscopy. The rich defect sites and excellent chemisorption property can thus induce reversible carbon-oxygen interface for the excellent ORR activity.

Cobalt phosphide/carbon dots composite as an efficient electrocatalyst for oxygen evolution reaction.

The oxygen evolution reaction (OER) is a promising energy conversion system, which has been studied a lot in recent years. However, owing to the high overpotential and sluggish kinetics of the OER, an efficient electrocatalyst is necessary to lower the overpotential and accelerate the reaction. In this paper, we report a cobalt phosphide (CoP)/carbon dots (CDs) composite as an electrocatalyst for the OER for the first time. A facile two-step method was used to synthesize the CoP/CDs composite and the concentration of CDs in the composite was further regulated. The experimental results show that when the amount of CDs in the composite is 6 mg (28.79 wt%C), the obtained CoP/CDs composite exhibits optimal electrocatalytic activity (with an overpotential of 400 mV in 1 M KOH at a current density of 10 mA cm-2) and high stability towards the OER. The good electrocatalytic activity of the composite is attributed to the small size of CoP and CDs and rapid electron transfer of CDs.

Publisher Correction: A Co3O4-CDots-C3N4 three component electrocatalyst design concept for efficient and tunable CO2 reduction to syngas.

The original HTML version of this Article omitted to list Yeshayahu Lifshitz as a corresponding author and incorrectly listed Shuit-Tong Lee as a corresponding author.Correspondingly, the original PDF version of this Article incorrectly stated that "Correspondence and requests for materials should be addressed to X.J. (email: xin.jiang@uni-siegen.de), or to Y.L. (email: yangl@suda.edu.cn), or to S.-T.L. (email: shayli@technion.ac.il), or to Z.K. (email: zhkang@suda.edu.cn)", instead of the correct "Correspondence and requests for materials should be addressed to X.J. (email: xin.jiang@uni-siegen.de), or to Y. Liu (email: yangl@suda.edu.cn), or to Y. Lifshitz (email: shayli@technion.ac.il), or to Z.K. (email: zhkang@suda.edu.cn)".This has now been corrected in the PDF and HTML versions of the Article.

A Co3O4-CDots-C3N4 three component electrocatalyst design concept for efficient and tunable CO2 reduction to syngas.

Syngas, a CO and H2 mixture mostly generated from non-renewable fossil fuels, is an essential feedstock for production of liquid fuels. Electrochemical reduction of CO2 and H+/H2O is an alternative renewable route to produce syngas. Here we introduce the concept of coupling a hydrogen evolution reaction (HER) catalyst with a CDots/C3N4 composite (a CO2 reduction catalyst) to achieve a cheap, stable, selective and efficient route for tunable syngas production. Co3O4, MoS2, Au and Pt serve as the HER component. The Co3O4-CDots-C3N4 electrocatalyst is found to be the most efficient among the combinations studied. The H2/CO ratio of the produced syngas is tunable from 0.07:1 to 4:1 by controlling the potential. This catalyst is highly stable for syngas generation (over 100 h) with no other products besides CO and H2. Insight into the mechanisms balancing between CO2 reduction and H2 evolution when applying the HER-CDots-C3N4 catalyst concept is provided.

High-bright fluorescent carbon dot as versatile sensing platform.

The surface functionalization will introduce additional functional groups on carbon dots (CDs) surface and then enrich the properties of CDs. Here, we show the various surface functionalized CDs (-COOH, -OH, -SH, -NH2, etc, named as NS-CDs) were synthesized with fascinating features, including high quantum efficiency (38.9%), long-term stability and good biocompatibility. Notably, it can serve as multifunction fluorescent probe in sensing system, including label-free detections in hydrogen peroxide (H2O2) with a wide linear range (1.20 × 10-3 - 8.80 × 10-12M) and a low limit of detection (LOD, 1.00 × 10-12M); and glutathione, covering a concentration range of 2.00 × 10-3 - 1.00 × 10-7M and LOD of 1.00 × 10-7M. In addition, the NS-CDs as fluorescent probe could selectively detect metal ions (such as, Hg2+, 1.00 × 10-8 - 1.50 × 10-3M, 1.00 × 10-7M), antibiotics (tetracycline, 1.00 ×10-10 - 2.50 × 10-5M, 1.00 ×10-10M) and toxic pollutant (nitrobenzene, 5.00 × 10-7 to 1.00 × 10-3gL-1, 5.00 × 10-7gL-1) with wide linear range and satisfactory detection limits.

New Insight of Water-Splitting Photocatalyst: H2O2-Resistance Poisoning and Photothermal Deactivation in Sub-micrometer CoO Octahedrons.

Hydrogen production by photocatalytic overall water-splitting represents an ideal pathway for clean energy harvesting, for which developing high-efficiency catalysts has been the central scientific topic. Nanosized CoO with high solar-to-hydrogen efficiency (5%) is one of the most promising catalyst candidates. However, poor understanding of this photocatalyst leaves the key issue of rapid deactivation unclear and severely hinders its wide application. Here, we report a sub-micrometer CoO octahedron photocatalyst with high overall-water-splitting activity and outstanding ability of H2O2-resistance poisoning. We show that the deactivation of CoO catalyst originates from the unintended thermoinduced oxidation of CoO during photocatalysis, with coexistence of oxygen and water. We then demonstrate that introduction of graphene, as a heat conductor, largely enhanced the photocatalytic activity and stability of the CoO. Our work not only provides a new insight of CoO for photocatalytic water splitting but also demonstrates a new concept for photocatalyst design.

A Pt-Co3O4-CD electrocatalyst with enhanced electrocatalytic performance and resistance to CO poisoning achieved by carbon dots and Co3O4 for direct methanol fuel cells.

Highly efficient electrocatalysts remain huge challenges in direct methanol fuel cells (DMFCs). Here, a Pt-Co3O4-CDs/C composite was fabricated as an anode electrocatalyst with low Pt content (12 wt%) by using carbon dots (CDs) and Co3O4 nanoparticles as building blocks. The Pt-Co3O4-CDs/C composite catalyst shows a significantly enhanced electrocatalytic activity (1393.3 mA mg-1 Pt), durability (over 4000 s) and CO-poisoning tolerance. The superior catalytic activity should be attributed to the synergistic effect of CDs, Pt and Co3O4. Furthermore, the Pt-Co3O4-CDs/C catalyst was integrated into a single cell, which exhibits a maximum power density of 45.6 mW cm-2, 1.7 times the cell based on the commercial 20 wt% Pt/C catalyst.