Bifunctional ligand Co metal-organic framework derived heterostructured Co-based nanocomposites as oxygen electrocatalysts toward rechargeable zinc-air batteries.

Rational construction of efficient and robust bifunctional oxygen electrocatalysts is key but challenging for the widespread application of rechargeable zinc-air batteries (ZABs). Herein, bifunctional ligand Co metal-organic frameworks were first explored to fabricate a hybrid of heterostructured CoOx/Co nanoparticles anchored on a carbon substrate rich in CoNx sites (CoOx/Co@CoNC) via a one-step pyrolysis method. Such a unique heterostructure provides abundant CoNx and CoOx/Co active sites to drive oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), respectively. Besides, their positive synergies facilitate electron transfer and optimize charge/mass transportation. Consequently, the obtained CoOx/Co@CoNC exhibits a superior ORR activity with a higher half-wave potential of 0.88 V than Pt/C (0.83 V vs. RHE), and a comparable OER performance with an overpotential of 346 mV at 10 mA cm-2 to the commercial RuO2. The assembled ZAB using CoOx/Co@CoNC as a cathode catalyst displays a maximum power density of 168.4 mW cm-2, and excellent charge-discharge cyclability over 250 h at 5 mA cm-2. This work highlights the great potential of heterostructures in oxygen electrocatalysis and provides a new pathway for designing efficient bifunctional oxygen catalysts toward rechargeable ZABs.

Changing Paradigm for Vertigo/Dizziness Patients: a Retrospective Before-After Study from Tertiary Hospitals in Northwestern China.

BACKGROUND: Single disciplinary management of patients with vertigo and dizziness is an important challenge for most physicians in China. OBJECTIVE: To assess the impact of a new paradigm of practice (Clinic for Vertigo and Dizziness, CVD) performed by a multidisciplinary team (MDT) on diagnostic spectrum, medical costs, and patient satisfaction. DESIGN: Retrospective before-after study. PARTICIPANTS: Sample of 29,793 patients with vertigo/dizziness as primary complaint. MEASURES: Changes in diagnostic spectrum, medical costs, and patient satisfaction before and after the establishment of a CVD based on a 4-year database in three tertiary hospitals in northwestern China. KEY RESULTS: The most common diagnoses of patients with vertigo and dizziness were Meniere's disease (25.77%), cervical disease (25.00%), cerebral vascular disease (13.96%), vestibular syndrome (10.57%), and other etiologies (6.34%) before the CVD establishment. In contrast, after the CVD establishment, the most common diagnoses were BPPV (23.92%), vestibular migraine (15.83%), Meniere's disease (14.22%), CSD/PPPD (11.61%), and cerebral vascular diseases (4.45%). Extended implementation of a structured questionnaire for vertigo/dizziness and vestibular-oriented examinations (nystagmus, positional tests, HINTS) at the CVD resulted in a remarkable decline in the utility of CT/MRI and X-ray examination (p < 0.001). Meanwhile, medical costs in patients with vertigo/dizziness dropped by 11.5% (p < 0.001), with a significant improvement in patient satisfaction after the establishment of CVD (p < 0.001). CONCLUSIONS AND RELEVANCE: Our study suggested that the MDT paradigm of CVD practice may facilitate the medical management of patients with vertigo/dizziness and improve patient satisfaction.

Fabrication of MPEG-b-PMAA capped YVO4:Eu nanoparticles with biocompatibility for cell imaging.

A novel nanoparticle with multilayer core-shell architecture for cell imaging is designed and synthesized by coating a fluorescent YVO4:Eu core with a diblock copolymer, MPEG-b-PMAA. The synthesis of YVO4:Eu core, which further makes MPEG-b-PMAA-YVO4:Eu NPs adapt for cell imaging, is guided by the model determined upon the evaluation of pH and CEu%. The PMAA block attached tightly on the YVO4:Eu core forms the inner shell and the MPEG block forms the biocompatible outermost shell. Factors including reaction time, reaction temperature, CEu% and pH are optimized for the preparation of the YVO4:Eu NPs. A precise defined model is established according to analyzing the coefficients of pH and CEu% during the synthesis. The MPEG-b-PMAA-YVO4:Eu NPs, with an average diameter of 24 nm, have a tetragonal structure and demonstrate luminescence in the red region, which lies in a biological window (optical imaging). Significant enhancement in luminescence intensity by MPEG-b-PMAA-YVO4:Eu NPs formation is observed. The capping copolymer MPEG-b-PMAA improves the dispersibility of hydrophobic YVO4:Eu NPs in water, making the NPs stable under different conditions. In addition, the biocompatibility MPEG layer reduces the cytotoxicity of the nanoparticles effectively. 95% cell viability can be achieved at the NPs concentration of 800 mgL(-1) after 24h of culture. Cellular uptake of the MPEG-b-PMAA-YVO4:Eu NPs is evaluated by cell imaging assay, indicating that the NPs can be taken up rapidly and largely by cancerous or non-cancerous cells through an endocytosis mechanism.

Facile synthesis of multifunctional multi-walled carbon nanotube for pathogen Vibrio alginolyticus detection in fishery and environmental samples.

Interest in carbon nanotubes for detecting the presence of pathogens arises because of developments in chemical vapor deposition synthesis and progresses in biomolecular modification. Here we reported the facile synthesis of multi-walled carbon nanotubes (MWCNTs), which functioned as immuno-, magnetic, fluorescent sensors in detecting Vibrio alginolyticus (Va). The structures and properties of functionalized MWCNTs were characterized by ultraviolet (UV), Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), magnetic property measurement system (MPMS) and fluorescent spectra (FL). It was found that the functionalized MWCNTs showed: (1) low nonspecific adsorption for antibody-antigen, (2) strong interaction with antibody, and (3) high immune-magnetic activity for pathogenic cells. Further investigations revealed a strong positive linear relationship (R=0.9912) between the fluorescence intensity and the concentration of Va in the range of 9.0 × 10(2) to 1.5 × 10(6) cfum L(-1). Moreover, the relative standard deviation for 11 replicate detections of 1.0 × 10(4) cfum L(-1) Va was 2.4%, and no cross-reaction with the other four strains was found, indicating a good specificity for Va detection. These results demonstrated the remarkable advantages of the multifunctional MWCNTs, which offer great potential for the rapid, sensitive and quantitative detection of Va in fishery and environmental samples.

N-(Naphthalen-1-yl-methyl-idene)-4H-1,2,4-triazol-4-amine.

In the title mol-ecule, C(13)H(10)N(4), the dihedral angle between the triazole ring and the naphthalene ring system is is 56.1 (2)°. In the crystal, mol-ecules are connected by weak C-H⋯N hydrogen bonds into chains along [100]. A short intra-molecular C-H⋯N contact is also observed.

The triclinic form of di-µ-aqua-bis-[diaqua-bis-(thio-cyanato-κN)iron(II)]-1,4-bis-(4H-1,2,4-triazol-4-yl)benzene (1/3).

In the title compound, [Fe(2)(NCS)(4)(H(2)O)(6)]·3C(10)H(8)N(6), the centrosymmetric dinuclear complex contains two Fe(II) ions bridged by two aqua ligand O atoms, forming a four-membered ring. The slightly distorted octa-hedral coordination environment of the two Fe(II) ions is completed by two monodentate aqua ligands and two thio-cyanate ligands. One of the 1,4-bis-(4H-1,2,4-triazol-4-yl)benzene mol-ecules lies across an inversion center. In the crystal, O-H⋯N hydrogen bonds connect the components, forming a two-dimensional network parallel to (011). In addition, π-π stacking inter-actions involving the benzene and triazole rings, with centroid-centroid distances in the range 3.502 (5)-3.787 (6) Å, connect the two-dimensional hydrogen-bonded network into a three-dimensional network.

1,4-Bis(4H-1,2,4-triazol-4-yl)benzene dihydrate.

The asymmetric unit of the title compound, C(10)H(8)N(6)·2H(2)O, comprises half the organic species, the mol-ecule being completed by inversion symmetry, and one water mol-ecule. The dihedral angle between the 1,2,4-triazole ring and the central benzene ring is 32.2 (2)°. The water mol-ecules form O-H⋯N hydrogen bonds with N-atom acceptors of the triazole rings. C-H⋯N hydrogen bonds are also observed, giving a three-dimensional framework.

In situ modifying of carbon tube-in-tube nanostructures with highly active Fe(2)O(3) nanoparticles.

A novel in situ method based on a liquid membrane templated self-assembly process is employed to modify carbon tube-in-tube nanostructures (TTCNTs) with Fe(2)O(3) nanoparticles. The as-obtained Fe(2)O(3) modified TTCNTs (Fe(2)O(3)/TTCNTs) nanocomposites are well constructed and the Fe(2)O(3) nanoparticles are well dispersed and decorated on the outer, inner and intramolecular surfaces of TTCNTs. In addition, the Fe(2)O(3)/TTCNTs nanocomposites are employed as catalysts for selective catalytic reduction (SCR) of NO with NH(3) and show high SCR catalytic activity, indicating that the novel multiple intramolecular channels and unique surface chemistry of the TTCNTs should play an important role in improving the properties of TTCNTs.

Particle-wire-tube mechanism for carbon nanotube evolution.

The synthesis of carbon nanotubes (CNTs) has been proved to be greatly promoted by vapor metal catalysts, but the fast reaction feature and the required high-temperature environment involved in CNT evolution usually make it difficult for an insight into the evolution mechanism. Here, we successfully freeze the synthetic reaction at intermediary stages and observe the detailed morphologies and structures of the obtained intermediates and various objects related to carbon nanotubes. It is unveiled that there is a kindred evolution linkage among carbon nanoparticles, nanowires, and nanotubes in the vapor catalyst-involved synthetic processes: tiny carbon nanoparticles first form from a condensation of gaseous carbon species and then self-assemble into nanowires driven by an anisotropic interaction, and the nanowires finally develop into nanotubes, as a consequence of particle coalescence and structural crystallization. The function of metals is to promote the anisotropic interactions between the nanoparticles and the structural crystallization. An annealing transformation of carbon nanoparticles into nanotubes is also achieved, which gives further evidence for the evolution mechanism.