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The wrinkles are pervasive in ultrathin two‐dimensional (2D) materials, but the regulation of wrinkles is rarely explored systematically. Here, we employed a series of carboxylic acids (from formic acid to octanoic acid) to control the wrinkles of Zr‐BTB (BTB=1, 3, 5‐(4‐carboxylphenyl)‐benzene) metal–organic framework (MOF) nanosheet. The wrinkles at the micrometer scale were observed with transmission electron microscopy. Furthermore, high‐angle annular dark‐field (HAADF) images showed lattice distortion in many nanoscale regions, which was precisely matched to the nano‐wrinkles. With the changes of hydrophilicity/hydrophobicity, MOF‐MOF and MOF‐solvent interactions were possibly synergistically regulated and wrinkles with different sizes were obtained, which was supported by HAADF, molecular dynamics, and density functional theory calculation. Different wrinkle sizes resulted in different pore sizes between the Zr‐BTB nanosheet interlayers, providing highly‐oriented thin films and the successive optimization of kinetic diffusion pathways, proved by grazing‐incidence wide‐angle X‐ray scattering and nitrogen adsorption. The most suitable wrinkle pore from Zr‐BTB‐C4 exhibited highly efficient chromatographic separation of the substituted benzene isomers. Our work provides a rational route for the modulation of nanoscale wrinkles and their stacked pores of MOF nanosheets and improves the separation abilities of MOFs. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: With the continuous development of nanotechnology, single‐molecule nanopore detection has become a popular research topic. In this review, we summarize the application of biological nanopores for metal ions detection as well as overview the function of metal ions in the ion‐mediated nanopore detection of different analytes in recent decades. According to the previous reports, biological nanopores utilize two strategies to detect metal ions. First, the specific binding sites are engineered in the nanopore to slow down the translocation rate of metal ions, resulting in the diverse specific current blockage signals. Secondly, the external molecule probes are added in the detection system to interact with metal ions, leading to the characteristic changes in the signals. At the same time, the external addition of metal ions into the nanopore detection systems enhances the sensitivity and selectivity through the changes of pore charges, the coordination with analytes or indirect detection. This review provides a summary on the role of metal ions in the application of nanopore detection technology. [ABSTRACT FROM AUTHOR]

Background: The association between thyroid hormone sensitivity and thyroid cancer is unknown, and we aimed to investigate the association between sensitivity to thyroid hormone indices and papillary thyroid carcinoma (PTC) in Chinese patients with thyroid nodules (TNs). Methods: A total of 1,998 patients undergoing thyroid surgery due to TNs from Nanjing Drum Tower Hospital were included in this study. We evaluated central sensitivity to thyroid hormones, such as thyroid stimulating hormone index (TSHI), TSH T4 resistance index (TT4RI), thyroid feedback quantile-based index (TFQI), and parametric thyroid feedback quantile-based Index (PTFQI). Peripheral sensitivity to thyroid hormone was evaluated by FT3 to FT4 ratio. Multivariate logistic regression analysis was performed to evaluate the association between sensitivity to thyroid hormone indices and PTC risk. Results: The results showed that central indices of thyroid hormone sensitivity, including TSHI, TT4RI, TFQI, and PTFQI, were positively associated with PTC risk. For each SD increase in TSHI, TT4RI, TFQI, and PTFQI, the odds ratios (OR, 95% CI) of PTC were 1.31 (1.18–1.46), 1.01 (1.01–1.02), 1.94 (1.45–2.60), and 1.82 (1.41–2.34), respectively. On the other hand, the association between peripheral sensitivity to thyroid hormone and PTC was significantly negative. For each SD increase in FT3/FT4 ratio, the OR (95% CI) of PTC was 0.18 (0.03–0.96), and a negative correlation was found between FT3/FT4 ratio and TNM staging of PTC. Conclusions: Sensitivity to thyroid hormone indices could be used as new indicators for predicting PTC in Chinese patients with TNs. Future researches are still needed to confirm our findings. [ABSTRACT FROM AUTHOR]

Nanopore technology is a burgeoning detection technology for single‐molecular sensing and ion rectification. Solid‐state nanopores have attracted more and more attention because of their higher stability and tunability than biological nanopores. However, solid‐state nanopores still suffer the drawbacks of low signal‐to‐noise ratio and low resolution, which hinder their practical applications. Thus, developing operatical and useful methods to overcome the shortages of solid‐state nanopores is urgently needed. Here, we summarize the recent research on nanopore modification to achieve this goal. Modifying solid‐state nanopores with different coating molecules can improve the selectivity, sensitivity, and stability of nanopores. The modified molecules can introduce different functions into the nanopores, greatly expanding the applications of this novel detection technology. We hope that this review of nanopore modification will provide new ideas for this field. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are one kind of highly porous crystalline materials, which are constructed by metal-containing inorganic nodes and organic linkers. With large surface area and high thermal stability, MOFs have great potential as sorbents for the preconcentration of trace analytes. However, such application of MOFs to the analysis of real samples has not been reported before. Here we report the utilization of MOF-5 as sorbent for infield sampling and preconcentration of atmospheric formaldehyde before thermal desorption (TD) GC/MS (TD-GC/MS) determination without the need for any chemical derivatization. MOF-5 gave a 53 and 73 times better concentration effect than Tenax TA (organic polymers) and Carbograph 1TD (graphitized carbon black), respectively, for TD-GC/MS determination of formaldehyde. MOF-5 showed good performance for in-field sampling and preconcentration of formaldehyde from air samples with a relative humidity less than 45%. The collected formaldehyde on MOF-5 sorbent was stable for at least 72 h at room temperature before TD-GC/MS analysis. One tube packed with 300 mg of MOF-5 lasted 200 cycles of adsorption/TD without significant loss of collection efficiency. The breakthrough volume of such a tube was 1.2 L of 28.35 mg m 3 formaldehyde at a sampling flow rate of 100 mL min 1. The use of MOF-5 for in-field sampling and preconcentration in combination with TD-GC/MS for the determination of formaldehyde offered a linear range covering 3 orders of magnitude, and a detection limit of 0.6 pg m 3. The precision for six replicate cycles of in-field sampling and preconcentration for TD-GC/MS determination using one 300 mg MOF-5 packed tube ranged from 2.8% to 5.3%. The tube-to-tube reproducibility of three MOF-5 tubes prepared in parallel was 7.7%. The developed method was applied to analysis of local indoor and outdoor air samples for formaldehyde and validated by the standard method TO-11A of the United States Environmental Protection Agency. The concentration of formaldehyde and the recovery of spiked formaldehyde in the air samples ranged from 12 to 48 pg [m.sup.-3], and from 93% to 107%, respectively. 10.1021/ac902450f

Metal-organic frameworks (MOFs) have received great attention due to their fascinating structures and intriguing potential applications in various fields. Herein, we report the first example of the utilization of MOFs for solid-phase microextraction (SPME). MOF-199 with unique pores and open metal sites (Lewis acid sites) was employed as the coating for SPME fiber to extract volatile and harmful benzene homologues. The SPME fiber was fabricated by in situ hydrothermal growth of thin MOF-199 films on etched stainless steel wire. The MOF- 199-coated fiber not only offered large enhancement factors from 19 613 (benzene) to 110 860 (p-xylene), but also exhibited wide linearity with 3 orders of magnitude for the tested benzene homologues. The limits of detection for the benzene homologues were 8.3-23.3 ng [L.sup.-1]. The relative standard deviation (RSD) for six replicate extractions using one SPME fiber ranged from 2.0% to 7.7%. The fiber-to-fiber reproducibility for three parallel prepared fibers was 3.5%-9.4% (RSD). Indoor air samples were analyzed for the benzene homologues using the SPME with the MOF- 199-coated fiber in combination with gas chromatography-flame ionization detection. The recoveries for the spiked benzene homologues in the collected indoor air samples were in the range of 87%-106%. The high affinity of the MOF-199-coated fiber to benzene homologues resulted from the combined effects of the large surface area and the unique porous structure of the MOF-199, the [pi]-[pi] interactions of the aromatic rings of the analytes with the framework 1,3,5-benzenetriearboxylic acid molecules, and the [pi]-complexation of the electron-rich analytes to the Lewis acid sites in the pores of MOF-199. 10.1021/ac901663x