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Most studies are devoted to the use of metal-organic frameworks (MOFs) as templates to construct desirable electrocatalysts in situ by high-temperature pyrolysis. The emergence of heterostructures invokes new opportunities to use the full potential of pristine MOFs as efficient catalysts in the oxygen evolution reaction (OER). Here, a MOF surface-reaction strategy is developed to synthesize MOF-based heterostructures without pyrolysis. Uniform Fe(OH)3 nanosheets are grown controllably on the Co-MOF-74 surface by a fast "phenol-Fe" reaction that takes advantage of the hydroxyl sites in Co-MOF-74. The resulting Fe(OH)3 @Co-MOF-74 heterostructure delivers an excellent performance in the OER with a low overpotential of 292 mV at 10 mA cm-2 . Notably, the introduction of Fe can improve the intrinsic activity of the original Co atom significantly. The turnover frequency in Fe(OH)3 @Co-MOF-74 (1.209 s-1 ) is more than 25 times higher than that in Co-MOF-74 (0.048 s-1 ). This work presents a fresh concept for the fundamental design of advanced pure-MOF-based heterostructures and, thereby, provides a new avenue for the fabrication of other energy-conversion and -storage materials.

Low charge-separation transport efficiency resulting from structural defects largely limits photocatalytic hydrogen production over polymeric graphitic carbon nitride (PCN) photocatalyst. Herein, an electron-donating group, namely p-phenylene, is incorporated into PCN by a polycondensation reaction between carbon nitride and p-phenylenediamine (or p-benzoquinone) to repair the structural defects. The p-phenylene-modified PCN exhibits an almost fivefold increase in H2 evolution, a threefold increase in photocurrent density, and higher nonradiative rate (0.285 ns-1 ). Spectroscopic studies confirm that p-phenylene tends to bridge the heptazine-based oligomers through a polycondensation reaction. Theoretical calculations reveal that anchoring of the heptazine units by p-phenylene induces localization of h+ and e- on the phenylene and melem moieties, respectively, which effectively separates the charge carriers. This strategy provides an opportunity to overcome structural defects in carbon nitride for efficient photocatalytic solar energy conversion.

Background Acute coronary syndrome (ACS) is the leading cause of death in developing and developed countries, yet assessing the risk of its development remains challenging. Several lines of evidence indicate that small, dense low‐density lipoproteins (sd‐LDL) are associated with increased cardiovascular disease risk. We aim to evaluate sd‐LDL concentration for predicting the risk of ACS in Chinese population. Methods Baseline characteristics of 121 patients with ACS and 172 healthy controls were obtained. Plasma sd‐LDL‐C was measured using homogeneous assay, and the proportion of sd‐LDL‐C in LDL‐C was detected. Results There was gender and age effect on the sd‐LDL‐C concentration and sd‐LDL‐C/LDL‐C ratio among healthy subjects. Elevated sd‐LDL‐C concentrations and sd‐LDL‐C/LDL‐C ratio were observed in ACS patients with unstable angina pectoris (UAP), non–ST‐segment elevation myocardial infarction (STEMI), and ST‐segment elevation myocardial infarction (NSTEMI) compared with healthy controls (P

A method for X-ray computed tomography quantification of damage in concrete under compression considering irreversible mode-II microcracks is developed. To understand damage behaviour in concrete, a micromechanical analysis of damage under biaxial compression is conducted focusing on random micro-defects in micro-cells isolated from the representative volume element. Furthermore, for stress–strain response prediction, a quantification is developed concerning the behaviours of the dominant macrocracks in multiaxial compression. Specifically, two crack types are taken into account: mode-I cracks and irreversible deformation cracks (including mode-II microcracks). Furthermore, mode-I cracks generate compression-induced tensile load (transverse) area reduction and further stiffness degradation, whereas the latter contribute to the development of irreversible strains. Additionally, by investigating the development of gradually converging dominant cracks, the procedure for quantifying damage is competently executed. In addition, distinguished from other approaches, the quantified damage can be applied directly to constitutive models to produce stress–strain response highly agrees with experimental results.

A simple damage model with the concept of mode-II microcracks on crack wall contributing to the irreversible strains for concrete is developed. By applying the micromechanics method, a microcell-based damage model is introduced to understand the damage behaviour. Further, by introducing the physical interpretation of the damage variable using thermodynamic method, a novel damage variable (irreversible-damage variable) is proposed to describe the irrecoverable strains generated by both mode-II microcracks and irreversible-frictional sliding. With this methodology, a simple continuum damage mechanics model is developed in which both elastic and irreversible damages are considered. As demonstrated by the comparison with experimental results, the proposed model is characterized by accuracy of solutions, sufficiency of physical sense and convenience of implementation.

Magnetic iron oxide coated in hydrogenation silica (Fe3O4@HSiO2) is constructed as both a tumor drug carrier and a magnetic resonance (MR) contrast agent. Colchicine (COLC) is loaded in Fe3O4@HSiO2 with the highest amount of 28.3 wt% at pH 9. The release performance of COLC can be controlled by pH, as the porous HSiO2 shell can partially shed at pH below 3.0 to facilitate the release of COLC. MR imaging (MRI) tests prove that Fe3O4@HSiO2 at pH 3.0 (H+-Fe3O4@HSiO2) shows a stronger MR contrast enhancement than Fe3O4. Cytotoxicity experiment indicates that Fe3O4@HSiO2 has excellent biocompatibility and magnetic targeting performance. Additionally, COLC-loaded Fe3O4@HSiO2 (Fe3O4@HSiO2–COLC) displays a higher inhibition effect on tumor cells under a magnetic field than free COLC. The visibility upon MRI, high targeting, and pH-controlled release characteristics of Fe3O4@HSiO2–COLC are favorable to achieve the aim of reducing side effects to normal tissues, making Fe3O4@HSiO2–COLC an attractive drug delivery system for nanomedicine.

Five aluminoborates Al[B5O10]·H2dab·2H2O (1), [Al(B4O9)(BO)]·H2en (2), [Al(B4O9)(BO)]·H2dap (3), K2Al[B5O10]·4H2O (4), and (NH4)2Al[B5O10]·4H2O (5) have been synthesized under hydrothermal conditions and characterized by means of elemental analysis, IR, TG analysis, MAS NMR, UV−vis and fluorescence spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction, and NLO determination. The structure 1 comprises of AlO4 tetrahedra and B5O10 clusters and contains 12-, 11-, and 8-MR 3D-intersecting channels with a CrB4 topological net. Structures 2 and 3 are both constructed from the same AlB5O13 clusters and exhibit a six-connected framework with 41263 topology. Structures 4 and 5 are isomorphous and are composed of AlO4 tetrahedra and B5O10 clusters that possess odd 11-MR channels and 8-MR helical channels. Structures 2−5 crystallized in an acentric structure and presented good SHG properties. UV−vis spectral investigation indicates that they are wide-band-gap semiconductors. The electronic structu...