Search

Background: Currently, insufficient bone volume always occurs in the posterior maxilla which makes implantation difficult. Short implants combined with transcrestal sinus floor elevation (TSFE) may be an option to address insufficient bone volume. Purpose: The clinical performance of short implants combined with TSFE was compared with that of conventional implants combined with TSFE according to the survival rate. Method: In this systematic review and meta-analysis, we followed the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Articles were identified through PubMed, Embase, the Cochrane Library, and manual searching. Eligibility criteria included clinical human studies. The quality assessment was performed according to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. The odds ratio (OR) with its confidence interval (CI) was considered the essential outcome for estimating the effect of short implants combined with TSFE. Results: The registration number is INPLASY202050092. Eleven studies met the inclusion criteria, including 1 cohort study and 10 cross-sectional studies. With respect to the 1-year survival rate, no significant effect was observed between short implants (length ≤ 8 mm) and conventional implants combined with TSFE (I2=0%, OR=1.04, 95% CI: 0.55-1.96). Similarly, no difference was seen between the two groups regarding the survival rate during the healing period (I2=10%, OR=0.74, 95% CI: 0.28-1.97) and 3-year loading (OR=1.76, 95% CI: 0.65-4.74). Conclusion: There was no evidence that the survival rate of short implants combined with TSFE was lower or higher than that of conventional implants combined with TSFE when the residual bone height was poor and the implant protrusion length of short implants was less than or similar to conventional implants. Nevertheless, the results should be interpreted cautiously due to the lack of random controlled trials in our meta-analysis. [ABSTRACT FROM AUTHOR]

The first mixed-valence nickel-supported polyoxometalate-based metal–organic framework, (H2mim)[NiIII(Hmim)4][SiW11NiIIO37(OH)2(Hmim)]·3H2O (1) (Hmim = 2-methylimidazole), has been synthesized using a steam-assisted conversion method, and is constructed from noncovalent interactions (hydrogen bonds and π…π stacking interactions). 1 has a repeating honeycomb-shaped internal structure with one-dimensional channels along the direction of the c axis, where the diameter of the aperture is as large as 18.83 Å. Furthermore, the stability and the optical band gaps are investigated. [ABSTRACT FROM AUTHOR]

The first polyoxometalate-based metal–organic nanotube constructed via covalent bonds has been synthesized. POM anions stick the metal–organic nanotubes to build 3D nanotubular arrays. The stability, magnetic and proton conducting properties are investigated. [ABSTRACT FROM AUTHOR]

A series of organic–inorganic hybrid compounds built from Keggin and Wells–Dawson polyoxometalates and TM-trz complexes (Htrz = 1,2,4-triazole) were obtained at different pH values under hydrothermal conditions, namely, [Co2(H2O)2(Htrz)5][SiW12O40]·2.5H2O (1), [Zn5(Htrz)8(trz)2(H2O)8][SiW12O40]2·10H2O (2), [CuI2CuII4(Htrz)4(trz)4Cl2][GeW12O40]·15H2O (3), [CuI2CuII4(Htrz)4(trz)4Cl2][SiW12O40]·15H2O (4), K2Na2(H2O)2[Co11(trz)14(H2O)14][P2W18O62]2·29H2O (5) and [Cu12(trz)10(Htrz)2(OH)4(SO4)2(H2O)6][P2W18O62]·28H2O (6). All of the compounds were characterized using single-crystal X-ray diffraction, TG analysis and powder X-ray diffraction. Compound 1 contains a kind of bimetallic–organic segment [Co2(Htrz)5]4+, which could be regarded as a quasi-sinusoid-like chain. 2 is a dimer constructed from two [SiW12O40]4− units linked by a [Zn5(trz)2(Htrz)8]8+ motif. In 3 and 4, the 2D wall-like layers constructed by the Cu(ii) ions and Htrz ligands are extended into 3D frameworks by polyanions. 5 shows a complicated three-dimensional (3D) framework with a {412·612·84}{46}2 topology. Compound 6 is also a complicated 3D structure based on a triangular trinuclear Cu-trz unit and [P2W18O62] polyanions. To the best of our knowledge, 6 represents the largest copper cluster linked by amines in a POM system. Structural diversities reveal that the pH value of the reaction system plays a crucial role in the assembly of POM-based hybrids. Moreover, the optical band gaps, electrochemical properties, magnetic properties and the photocatalytic properties of the compounds have been investigated. [ABSTRACT FROM AUTHOR]

Three cobalt(II)-containing tungstophosphate compounds, Na8Li8Co5[Co5.5(H2O)19P8W48.5O184] ⋅60 H2O ( 1), K2Na4Li11Co5[Co7(H2O)28P8W48O184]Cl ⋅ 59 H2O ( 2), and K2Na4LiCo11[Co8(H2O)32P8W48O184](CH3COO)4Cl ⋅47 H2O ( 3), have been synthesized and characterized by IR spectroscopy, thermogravimetric analysis, elemental analyses, and magnetic measurements. The pH value impacts the formation of distinct cobalt-linked frameworks. The cyclic cavity of the polyanion accommodates 5.5, 7, and 8 cobalt ions in 1, 2, and 3, respectively. In compounds 1 and 2, each {Co5.5P8W48} and {Co7P8W48} fragment links to four others through multiple {Co-O-W} coordination bonds to generate a two-dimensional network. Compound 3 can be considered as a 3D network based on the {Co-O-W} coordination bonds and the {Co3(CH3COO)2(H2O)10} linkers between the {P8W48} fragments. Interestingly, acetate ligands have been employed to form the {Co3(CH3COO)2(H2O)10} unit, thereby inducing the construction of a 12-connected framework. To the best of our knowledge, compound 3 contains the largest-ever number of cobalt ions in a {P8W48}-based polyoxometalate when counterions are taken into account and the {P8W48} unit shows the highest number of connections thanks to the carboxyl bridges. The UV/Vis diffuse reflectance spectra of these powder samples indicate that the corresponding well-defined optical absorption associated with Eg can be assessed at 2.58, 2.48, and 2.73 eV and reveal the presence of an optical band gap. The photocatalytic H2 evolution activities of these {P8W48}-based compounds are evaluated. [ABSTRACT FROM AUTHOR]

Making light work: Three novel W/Nb mixed‐addendum polyoxometalates, which all contain the {SiNb3W9O40} cluster, have been synthesized by conventional aqueous methods. Visible‐light photocatalytic H2 evolution activity (see figure) was observed for two of the compounds, with H2PtCl6 as a cocatalyst and triethylamine as a sacrificial electron donor. [ABSTRACT FROM AUTHOR]

Abstract: A new inorganic–organic hybrid compound constructed from Keggin-type polyoxometalate and cadmium-organic units, namely, [Cd(Htrz)3]2[SiW12O40]·2H2O (1), [Htrz=1-H-1,2,4-triazole], has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR, TG, and UV–vis absorption spectra. In compound 1, each [SiW12O40]4− cluster is modified by six [Cd(Htrz)3]2+ metal–organic fragments, meanwhile, each [Cd(Htrz)3]2+ also connects with three [SiW12O40]4− to built up a binodal (3,6)-connected 2D planar network with the (43)2(46·66·83)-kgd topology. Interestingly, [SiW12O40]4− cluster exhibits a rare coordination mode acting as a hexadentate ligand, in which all of the six terminal oxygen atoms in the equatorial plane are synchronously participated in coordination. The diffuse reflectivity spectrum shows it can be regarded as a wide gap semiconductor. Moreover, the photocatalytic performance shows good photocatalytic activity for the degradation of Rhodamine B. [Copyright &y& Elsevier]

Searching for high-efficient, good long-term stability, and low-cost electrocatalysts toward oxygen reduction reaction (ORR) is highly desirable for the development of sustainable energy conversion devices. Iron–nitrogen doped carbon (Fe–N/C) catalysts have been recognized as the most promising candidates for traditional Pt-based catalysts that benefit from their high activity, excellent anti-poisoning ability, and inexpensiveness. Here, a super-dispersed and high-performance Fe–N/C catalyst was derived from chemically Fe-doped zeolitic imidazolate frameworks (ZIFs) by directly bonding Fe ions to imidazolate ligands within 3D frameworks. It produced a series of catalysts, whose sizes could be tuned in the range from 62 to over 473 nm in diameter. After rationally regulating the component and heating treatment, the best ORR activity was measured for the catalyst with a size of 105 nm, which was obtained when the Fe3+/Zn2+ molar ratio was 0.05 and carbonization temperature was 900 °C. It exhibited a high onset potential (Eonset = 0.99 V) and half-wave potential (E1/2 = 0.885 V) compared with a commercial 20% Pt/C catalyst (Eonset = 0.10 V, E1/2 = 0.861 V) as well as much better durability and methanol resistance in an alkaline electrolyte. [ABSTRACT FROM AUTHOR]

Three novel self-catenated 4-connected uninodal (65·8)-mok metal–organic rotaxane frameworks (MORFs) containing cucurbit[6]uril were constructed from the in situ trans/cis-configuration (1 : 1) of rotaxanes by taking advantage of a d10 metal ion directed synthesis. It was revealed that the effect of hydrogen bonds and π–π stacking interactions play significant roles in the self-assembly process. [ABSTRACT FROM AUTHOR]

A new three-dimensional metal–organic framework constructed form pentanuclear tetrahedral cluster and linear dicarboxylic acid ligand, [Zn 5 (btz) 6 (ndc) 2 (H 2 O)]·3DMA ( 1 ) (btz = benzotriazole, H 2 ndc = 1,4-naphthalenedicarboxylic acid) has been synthesized by the modular building blocks (MBBs) strategy under the solvothermal condition. Single X-ray diffraction reveals that 1 is a two-fold interpenetrated framework with mdf topology, in which pentanuclear {Zn 5 (btz) 6 } cluster acts as a 4-connected node. Moreover, the luminescent properties of 1 dispersed in different metal ions and solvents have been investigated systematically. [ABSTRACT FROM AUTHOR]