Design and Fabrication of Hypercrosslinked Covalent Organic Adsorbents for Selective Uranium Extraction.

Uranium detection and extraction are necessary for the ecological environment as the growing demand for nuclear energy. Hence, exploring stable materials with excellent performance in uranium extraction and detection is highly desired. Herein, by amidoxime-functionalizing tetrafluoroterephthalonitrile (TFTPN) crosslinked hydroquinone (bP), phloroglucinol (tP), and 4,4',4″-trihydroxytriphenylmethane (tBP), three covalent organic polymers (COPs) bPF-AO, tPF-AO, and tBPF-AO with different crosslinked architectures are fabricated. Uranium extraction and detection related to the difference in molecule construction were systemically investigated, giving some reference for the rational design and fabrication of advanced materials for the removal and monitoring of uranium in the environment. The tPF-AO with a compact steric structure achieves the highest theoretical maximum adsorption capacity of 578.9 ± 15.2 mg g-1 and the best recyclability. The scattering electron center and U(VI) selective binding sites endow tBPF-AO with excellent capability in selective detection for U(VI), with a limit of detection of 24.2 nmol L-1, which is well below the standard for U(VI) in drinking water of the World Health Organization (WHO). Moreover, the COPs possess prominent physicochemical stability and recyclability, and more importantly, the PAE-based COPs are derived from inexpensive industry materials with easy processing methods, providing an efficient and economical way for the detection and adsorption of uranium.

Selective and Efficient Photoextraction of Aqueous Cr(VI) as a Solid-State Polyhydroxy Cr(V) Complex for Environmental Remediation and Resource Recovery.

Aqueous hexavalent chromium (Cr(VI)) treatment and chromium resource recovery toward Cr-containing wastes are of significant importance and necessity to both wastewater remediation and resource recovery. Herein, via mild photoreaction conditions with isopropanol (IPA) as an electron donor, a catalyst-free strategy for aqueous Cr(VI) extraction to form an insoluble polyhydroxy Cr(V) complex is developed for the first time. Aqueous Cr(VI) with concentration from 5 to 150 ppm can be efficiently extracted with high selectivity even in the presence of coexisting ions, and the total Cr concentration in residue solution can be as low as 0.5 ppm. The Cr resource could be efficiently recovered as pure Cr2O3 by calcinating the resulting Cr(V) precipitate. Outstanding extraction efficiency could be realized with various IPA concentrations (1.3-12.0 mol/L) by coordinately tuning the pH value to promote the formation of Cr(VI)-IPA ester. The formed ester undergoes intramolecular electron transition under visible light irradiation, resulting in a polyhydroxy solid-state Cr(V) intermediate complex. The controlled pH value blocks further reduction of Cr(V) to soluble Cr(III); thus the insoluble Cr(V) intermediate complex is stabilized thermodynamically under ambient conditions. Because of its electric neutrality property and the strong intermolecule interaction via hydrogen bonds, a dioxo-bridged di-nuclear Cr(V) complex {Cr2(µ-O)2(OH)4[OCH(CH3)2]2} is finally precipitated as the main product. Satisfactory extraction and recovery of Cr from chromium-plating wastewater and discarded stainless steel verify that this approach is ideal for both one-step purification of Cr(VI)-containing wastewater and selective resource recovery from Cr-containing solid wastes in practical application.

Correction to: Perceptions of traditional Chinese medicine for chronic disease care and prevention: a cross-sectional study of Chinese hospital-based health care professionals.

Following publication of the original article [1], the author reported that the funding information was missing from the original article.

Perceptions of traditional Chinese medicine for chronic disease care and prevention: a cross-sectional study of Chinese hospital-based health care professionals.

BACKGROUND: In China, demands for disease prevention and health care and the prevalence of chronic non-communicable diseases have increased. TCM and general hospitals are increasingly utilizing TCM strategies for chronic non-communicable disease care and prevention. This study aimed to investigate health care professionals' (HCPs') perceptions of TCM for prevention, their TCM knowledge, and their abilities to provide such services in TCM and general hospitals. METHODS: This cross-sectional study investigated Chinese medicine hospitals and Chinese medicine departments in general hospitals in five Chinese cities. A self-designed questionnaire used to study 400 HCPs focused on basic demographic data, the demand for and effects of TCM for prevention and treatment, and their perceptions of such service implementation. The data analysis included chi-squared tests and descriptive and multi-factor analyses. RESULTS: The 335 HCP respondents comprised 230 (68.7%) females and 105 (31.3%) males, 75.5% of whom overall had knowledge of TCM preventive and health care services. Respondents older than 40 years (28.6%) had greater knowledge of and satisfaction with TCM for preventive and health care services than younger respondents. Moreover, 97.7% of the older respondents were clearly willing to provide TCM preventive services for chronic diseases, 67.8% of whom indicated that their hospitals already provided TCM for prevention and treatment. According to the chi-squared test results, the TCM service characteristics in hospitals, hospital outlooks regarding TCM and TCM development in hospitals were the primary factors affecting the respondents' perceptions of TCM for chronic disease care and prevention. The multivariate analysis showed high satisfaction as significantly associated with older providers and those with lengthier work experience, particularly among those who worked in hospitals that provided typical TCM services and had positive attitudes towards TCM. CONCLUSION: The study HCPs had relatively satisfactory knowledge of and positive attitudes towards TCM for chronic disease care and prevention and would use it in practice. Their perceptions and satisfaction levels correlated closely with the successful application of TCM for preventive care and treatment in hospitals. While the use of TCM for prevention and treatment was well developed in some hospitals, further improvements are warranted.

Single-displacement controlled spontaneous electrolysis towards CuTCNQ microribbon electrodes in organic single-crystal transistors.

Using single-displacement controlled spontaneous electrolysis solution-prepared CuTCNQ microribbons as the source/drain electrodes, we have fabricated 9,10-bis(2-phenylethynyl)anthracene (BEPA) based organic single crystal top-contact field-effect transistors. The interfacial energetic match between organic semiconductors and CuTCNQ electrodes with the low contact resistance accounts for the compelling improvement in electrical characteristics relative to the copper electrode, even comparable to gold counterparts. Furthermore, we have estimated the contact resistance of single-crystal transistors by the transfer line method (TLM).

State-of-the-art progress for the selective crystallization of actinides, synthesis of actinide compounds and their functionalization.

Crystallization and immobilization of actinides to form actinide compounds are of significant importance for the extraction and reutilization of nuclear waste in the nuclear industry. In this paper, the state-of-art progress in the crystallization of actinides are summarized, as well as the main functionalization of the actinide compounds, i.e., as adsorbents for heavy metal ions and organic pollutant in waste management, as (photo)catalysts for organic degradation and conversion, including degradation of organic dyes and antibiotics, dehydrogenation of N-heterocycles, CO2 cycloaddition, selective alcohol oxidation and selective oxidation of sulfides. This review will give a comprehensive summary about the synthesis and application exploration of solid actinide crystalline salts and actinide-based metal organic frameworks in the past decades. Finally, the future perspectives and challenges are proposed in the end to give a promising direction for future investigation.

"Spontaneous electrolysis" and simultaneously assembly hierarchy nanostructures of copper tetracyanoquinodimethane.

A simple method was developed to generate nanolamellas of CuTCNQ based on the principle of "spontaneous electrolysis". The nanolamellas were identified to belong to phase I of CuTCNQ. Intermediate products before nanolamellas were monitored with this method and beautiful artificial flowers were assembled based on the "spontaneous electrolysis." Moreover, CuTCNQ nanocrystal arrays could be grown on TCNQ single crystal surface homogeneously, which suggested a new method to assembly nanomaterials on crystal surface.

Possible Luttinger liquid behavior of edge transport in monolayer transition metal dichalcogenide crystals.

In atomically-thin two-dimensional (2D) semiconductors, the nonuniformity in current flow due to its edge states may alter and even dictate the charge transport properties of the entire device. However, the influence of the edge states on electrical transport in 2D materials has not been sufficiently explored to date. Here, we systematically quantify the edge state contribution to electrical transport in monolayer MoS2/WSe2 field-effect transistors, revealing that the charge transport at low temperature is dominated by the edge conduction with the nonlinear behavior. The metallic edge states are revealed by scanning probe microscopy, scanning Kelvin probe force microscopy and first-principle calculations. Further analyses demonstrate that the edge-state dominated nonlinear transport shows a universal power-law scaling relationship with both temperature and bias voltage, which can be well explained by the 1D Luttinger liquid theory. These findings demonstrate the Luttinger liquid behavior in 2D materials and offer important insights into designing 2D electronics.

The replacement reaction controlling the fractal assembly of copper nanoparticles.

In this paper we describe a fractal assembly of copper nanoparticles on different substrates by controlling the chemical replacement reaction. Through calculation, we found that the 'fractal dimensions' of copper dendrites synthesized by us were about 1.832, which agreed well with the 'fractal dimensions' of natural fern leaves (fractal dimension, 1.826), suggesting that the fern fractal model was useful to describe the self-assembly of our copper nanoparticles during the chemical replacement reaction process. These results will be beneficial for the understanding of the role that highly nonequilibrium conditions play in the formation of fractal clusters as well as the self-assembly mystique of metallic nanoparticles in nonequilibrium conditions and also helpful in the future assembly of complicated nanoarchitectures of metallic nanoparticles for potential applications.

A new morphology of copper 7,7,8,8-tetracyano-p-quinodimethane.

Morphology control is a long-standing problem that needs to be solved for making the switching mechanism of copper 7,7,8,8-tetracyano-p-quinodimethane (CuTCNQ) understood all the time, but up till now how many morphologies CuTCNQ possesses and which morphology should be responsible for the on/off switching phenomenon are still unclear. A new morphology of CuTCNQ, namely the tubular structure, has been obtained and characterized in our experiment, whose formation mechanism has also been investigated. Through characterizing, we can conclude that the tubular structure belongs to the phase I, which can be further confirmed by the electrical measurements. From the I-V plots, the carrier mobility of the tubular structure is estimated to be approximately 0.1 cm2 V-1 s-1, which suggests the potential application of CuTCNQ in devices.

Facilely and efficiently tuning metal-organic nanostructures of a charge-transfer complex based on a water controlled nanoreaction and the chemistry of 7,7,8,8-tetracyanoquinodimethane (TCNQ).

Metal-organic charge-transfer complexes based on 7,7,8,8-tetracyanoquinodimethane (TCNQ) have received considerable attention because of their unique solid-state physical properties for potential applications in nanoscale opto-electronic devices. To address the challenge in preparing novel metal-TCNQ (MTCNQ) nanostructures, here we introduce a facile and efficient way for synthesizing MTCNQ, taking Ni[TCNQ]2(H2O)2 as an example. By finely tuning the amount of water added into TCNQ solution, well-ordered and large-scale patterns of Ni[TCNQ]2(H2O)2 were successfully obtained in a controllable manner. This facile method will not only be beneficial for the tailored preparation of nanoscale MTCNQ complexes, but also enrich the chemistry of TCNQ.

Controlling the growth of single crystalline nanoribbons of copper tetracyanoquinodimethane for the fabrication of devices and device arrays.

In this paper, (1) a simple and controllable method to synthesize single crystalline nanoribbons of CuTCNQ in a large area was demonstrated by using a physical and chemical vapor combined deposition technique. (2) Nanoribbons synthesized by this method were identified to belong to phase I. (3) Devices and device arrays of nanoribbons were in situ fabricated by this method using gap electrodes and gap electrode arrays. (4) Current-voltage characteristics of crystalline devices and device arrays of nanoribbons exhibited semiconductor properties, and this conclusion was further confirmed by the results of devices based on an individual nanoribbon or microribbon of CuTCNQ (phase I). The controllable synthesis of nanoribbons for the in situ fabrication of crystalline nanodevices and device arrays will be attractive for nanoelectronics. Moreover, semiconductor current-voltage characteristics of the nanoribbons will be beneficial to the understanding of CuTCNQ.