Preparation of One-Dimensional Hollow Metal-Organic Frameworks via the Marangoni Effect.

The fabrication of one-dimensional hollow metal-organic frameworks (1D HMOFs) has attracted considerable attention for the catalysis and separation because of their large surface areas and short and continuous axial diffusion pathways. However, the fabrication of 1D HMOFs requires the use of a sacrificial template and multiple steps, limiting their potential applications. This study proposes a novel Marangoni-assisted method to synthesize 1D HMOFs. Using this method, the MOF crystals can undergo heterogeneous nucleation and growth, affording a morphology self-regulation process under kinetic control and forming tubular 1D HMOFs in one step without requiring additional treatment. This method is expected to open new avenues for synthesizing 1D HMOFs.

Au Nanoparticles@UiO-66 Composite Film-Coated Carbon Cloth Substrate for High-Performance H2O2 Electrochemical Sensing.

Due to the strong oxidizability of H2O2, rapid, accurate, sensitive, and stable sensors of hydrogen peroxide (H2O2) have attracted wide attention in the chemical industry, food, medicine, household detergents, and environmental monitoring fields. Here, a high-performance H2O2 electrochemical sensing platform is proposed based on an Au nanoparticles@UiO-66 film coated on a carbon cloth (CC) electrode (Au NPs@UiO-66/CC electrode). The Au NPs@UiO-66/CC electrode was prepared through solvothermal growth of a UiO-66 film on a functionalized three-dimensional CC electrode, followed by in situ deposition of Au NPs into the UiO-66 film under a periodic galvanostatic pulse current. The in situ preparation strategy greatly improves the electrical interaction between Au NPs@UiO-66 and the CC substrate without sacrificing the electrochemical activity of the Au NPs@UiO-66/CC electrode. Meanwhile, thanks to the high specific surface area of the three-dimensional Au NPs@UiO-66/CC electrode, the optimized Au NPs@UiO-66/CC electrode illustrates excellent electrochemical detection capability for H2O2 with an extensive linear range (0.1-21 mM), high sensitivity (1048.01 µA mM-1 cm-2), and lower limit of detection [0.033 µM (S/N = 3)] and limit of quantification [0.109 µM (S/N = 3)]. At the same time, the encapsulated structure of Au NPs in the UiO-66 film also endows the composite electrode with specific sensing performance owing to the regular opening channels of the UiO-66 films that prevent large-size interferents from reacting to the electrochemically active Au NPs. Together with all these advantages, the proposed sensing platform would exhibit great potential for electrochemical sensors and bioelectronics.

Controllable Fabrication of PdO-PdAu Ternary Hollow Shells: Synergistic Acceleration of H2 -Sensing Speed via Morphology Regulation and Electronic Structure Modulation.

Designing ultrafast H2 sensors is of particular importance for practical applications of hydrogen energy but still quite challenging. Herein, PdO decorated PdAu ternary hollow shells (PdO-PdAu HSs) exhibiting an ultrafast response of ≈0.9 s to 1% H2 in air at room temperature are presented. PdO-PdAu HSs are fabricated by calcinating PdAu bimetallic HSs in air to form PdO-Au binary HSs, which are then partially reduced by NaBH4 solution, forming PdO-PdAu HSs. This ternary hybrid material takes advantage of multiple aspects to synergistically accelerate the sensing speed. The HS morphology promises high gas accessibility and high surface area for H2 adsorption, and decoration of Au and PdO alters the electronic state of Pd and reduces the energy barrier for hydrogen diffusing from the surface site of Pd into the subsurface site. The content of Au and PdO in the ternary HSs can be simply tuned, which offers the possibility to optimize their promotion effects to reach the best performance. The proposed fabrication strategy sheds light on the rational design of ultrafast Pd-based H2 sensors by controlling the sensor structure and engineering the electronic state of active species.

Association of ABCG1 gene methylation and its dynamic change status with incident type 2 diabetes mellitus: the Rural Chinese Cohort Study.

To explore whether DNA methylation of the ATP-binding cassette G1 (ABCG1) gene and its dynamic change are associated with incident type 2 diabetes mellitus (T2DM). We conducted a nested case-control study with 286 pairs of T2DM cases and matched controls nested in the Rural Chinese Cohort Study. Conditional logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for incident T2DM risk according to ABCG1 methylation level at baseline and its dynamic change at follow-up examination. Spearman's rank correlation coefficients were used to analyze the association between ABCG1 methylation and its possible risk factors in the control group. We found that T2DM risk increased by 16% (OR = 1.16, 95% CI = 1.02-1.31) with each 1% increase in DNA methylation levels of the ABCG1 loci CpG13 and CpG14. DNA methylation change of the ABCG1 locus CpG15 during the 6-year follow-up was associated with increased T2DM risk: T2DM risk increased by 78% in the upper tertile group (methylation gain ≥5%) versus lower tertile group (methylation gain <1%) (OR = 1.78, 95% CI = 1.01-3.15). Furthermore, body mass index was positively correlated with the DNA methylation level of the ABCG1 loci CpG13, CpG14 and CpG15. In conclusion, DNA methylation levels of the ABCG1 loci CpG13 and CpG14 and the methylation gain of locus CpG15 were positively associated with incident T2DM risk, which may suggest a possible etiologic pattern for T2DM and potentially improve T2DM prediction in rural Chinese people.

Chinese visceral adiposity index: A reliable indicator of visceral fat function associated with risk of type 2 diabetes.

BACKGROUND: The evidence of the association between Chinese visceral adiposity index (CVAI) and risk of type 2 diabetes mellitus (T2DM) is limited. We explored the association of CVAI with T2DM and directly compared with the predictive power of CVAI with other visceral obesity indices (visceral adiposity index, waist to height ratio, waist circumference and body mass index) based on a large prospective study. METHODS: We conducted a population-based study of 12 237 Chinese participants. Cox proportional-hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between CVAI and T2DM. RESULTS: During follow-up (median: 6.01 years), the incidence of T2DM was 3.29, 7.34, 12.37 and 23.72 per 1000 person-years for quartiles 1, 2, 3 and 4 of CVAI, respectively. The risk of T2DM was increased with quartiles 2, 3 and 4 vs quartile 1 of CVAI (HR 2.12 [95% CI 1.50-3.00], 2.94 [2.10-4.13] and 5.01 [3.57-7.04], Ptrend < 0.001). Per-SD increase in CVAI was associated with a 72% increased risk of T2DM (HR 1.72 [95% CI 1.56-1.88]). Sensitivity analyses did not alter the association. The area under receiver operating characteristic curve was significantly higher for CVAI than other visceral obesity indices (all P <.001). Similar results were observed in stratified analyses by sex. CONCLUSIONS: Our findings show a positive association between CVAI and risk of T2DM. CVAI has the best performance in predicting incident T2DM, so the index might be a reliable and applicable indicator identifying people at high risk of T2DM.

High-performance plasmonic lab-on-fiber sensing system constructed by universal polymer assisted transfer technique.

Plasmonic lab-on-fiber (LOF) system has become an emerging sensing platform for the realization of miniaturized and portable plasmonic sensors. Herein, a facile and efficient polymer assisted transfer technique was reported for the preparation of plasmonic LOF systems. The proposed plasmonic LOF system was constructed through transferring plasmonic arrays to the end surface of optical fibers using polylactic acid as the sacrificial layer. The morphology of the transferred plasmonic arrays maintains excellent consistency with the original arrays. Importantly, the as-prepared plasmonic LOF system also possesses outstanding sensing performance in refractive index sensing and quantitative label-free biosensing applications. Additionally, the proposed polymer assisted transfer technique shows broad universality for various plasmonic arrays. Together with the above features, it is believed that the polymer assisted transfer technique will show great potential for the application of future plasmonic LOF systems.

Lab-on-fiber sensing system based on responsive Fabry-Perot optical resonance cavities prepared throughin situconstruction strategy.

For decades, lab-on-fiber (LOF) sensing systems have become an emerging optical sensing platform due to the features of small size and light weight. Herein, a simple and efficientin situconstruction strategy was reported for the preparation of LOF sensing platform based on the integration of responsive Fabry-Perot optical resonance cavity on optical fibers. The responsive Fabry-Perot optical resonance cavity with thermal poly(N-isopropylacrylamide) polymer brush layer sandwiched by two silver layers was constructed on the end surface of the optical fiber through combiningin situsurface-initiated polymerization and metal film deposition techniques. Owing to the thermo-responsiveness of the intermediate layer, the as-prepared LOF sensing system shows a sensitive response towards the environmental temperature. Importantly, the as-prepared LOF sensing system also possesses excellent repeatability and rapid response rate. Together with the features of high sensitivity, excellent repeatability and rapid response rate, we believe such LOF sensing system will provide a foundation for the future applications of medical diagnosis,in vivodetection and public security.

Structural and Morphological Transformation of Two-Dimensional Metal-Organic Frameworks Accompanied by Controlled Preparation Using the Spray Method.

An interesting reversible shape and structure transformation between two types of two-dimensional (2D) metal-organic frameworks (MOFs) has been successfully achieved by the spray method. The ability to precisely control the morphology and structure of 2D MOFs is also developed by altering the amount of MOF precursors and reversing the spray order. Meanwhile, the mechanism of the transformation between two MOFs is studied and conversion is induced by the change of the acidity in the reaction system. In addition, the prepared non-interpenetrate CuBDC twists exhibit more remarkable catalytic performance in C-S coupling reaction than Cu(BDC)(DMF) nanosheets owing to the more unsaturated coordination copper active sites from the non-interpenetrate structure. The catalytic result reveals the relationship between structure and function.

Sea urchin-like CuO particles prepared using Cu3(PO4)2 flowers as precursor for high-performance ethanol sensing.

Cu3(PO4)2 flowers are reported for the first time as a solid precursor for the preparation of hierarchical CuO particles with sea urchin-like morphology in the absence of self-assembled templates or matrixes. In the alkaline condition, Cu3(PO4)2 transforms into Cu(OH)2 firstly, and then into CuO through dehydration at room temperature. Different from soluble Cu salt as precursor, the basic building blocks for CuO are continuously supplied in a controlled manner form Cu3(PO4)2 precursor, which ensures a nearly sustained supersaturated concentration that favors heterogeneous nucleation and progressive growth of sea urchin-like CuO particles. The gas sensing property of as-prepared sea urchin-like CuO particles to ethanol is investigated. The sea urchin-like CuO particles exhibit a good sensing performance in terms of high response, short response/recovery time, good selectivity, good reproducibility, and long-term stability. The facile strategy demonstrated here opens up a new strategy to fabricate hierarchical CuO particles with enormous potential from the perspective of practical application.

Encapsulation of metal oxide nanoparticles inside metal-organic frameworks via surfactant-assisted nanoconfined space.

Encapsulation of metal oxide nanoparticles (MO NPs) inside metal-organic frameworks (MOFs) has been realized successfully via surfactant-assisted nano-confined space strategy, which is a universal method for various MO NPs@MOFs. The size of MO NPs was limited by the confined nano-space and could be adjusted to a certain extent. The synthesis mechanism of MO NPs@MOFs was revealed via detailed structural characterizations and a series of control experiments. Surfactants introduced during MOFs (CuBDC, BDC = 1,4-benzenedicarboxylic acid) formation process plays a very important role in producing uniform voids of nano-confined space. Cu ions in MOF frameworks were directly used as precursors to fabricate CuO NPs in these confined void spaces. The synthesized CuO@CuBDC composites showed excellent catalytic activity in C-S cross-coupling reactions and dye pollutant photo-degradation reactions.

Sugar and artificially sweetened beverages and risk of obesity, type 2 diabetes mellitus, hypertension, and all-cause mortality: a dose-response meta-analysis of prospective cohort studies.

Although consumption of sugar-sweetened beverages (SSBs) and artificially sweetened beverages (ASBs) has increasingly been linked with obesity, type 2 diabetes mellitus, hypertension, and all-cause mortality, evidence remains conflicted and dose-response meta-analyses of the associations are lacking. We conducted an updated meta-analysis to synthesize the knowledge about their associations and to explore their dose-response relations. We comprehensively searched PubMed, EMBASE, Web of Science, and Open Grey up to September 2019 for prospective cohort studies investigating the associations in adults. Summary relative risks (RRs) and 95% confidence intervals (CIs) were estimated for the dose-response association. Restricted cubic splines were used to evaluate linear/non-linear relations. We included 39 articles in the meta-analysis. For each 250-mL/d increase in SSB and ASB intake, the risk increased by 12% (RR = 1.12, 95% CI 1.05-1.19, I2 = 67.7%) and 21% (RR = 1.21, 95% CI 1.09-1.35, I2 = 47.2%) for obesity, 19% (RR = 1.19, 95% CI 1.13-1.25, I2 = 82.4%) and 15% (RR = 1.15, 95% CI 1.05-1.26, I2 = 92.6%) for T2DM, 10% (RR = 1.10, 95% CI 1.06-1.14, I2 = 58.4%) and 8% (RR = 1.08, 95% CI 1.06-1.10, I2 = 24.3%) for hypertension, and 4% (RR = 1.04, 95% CI 1.01-1.07, I2 = 58.0%) and 6% (RR = 1.06, 95% CI 1.02-1.10, I2 = 80.8%) for all-cause mortality. For SSBs, restricted cubic splines showed linear associations with risk of obesity (Pnon-linearity = 0.359), T2DM (Pnon-linearity = 0.706), hypertension (Pnon-linearity = 0.510) and all-cause mortality (Pnon-linearity = 0.259). For ASBs, we found linear associations with risk of obesity (Pnon-linearity = 0.299) and T2DM (Pnon-linearity = 0.847) and non-linear associations with hypertension (Pnon-linearity = 0.019) and all-cause mortality (Pnon-linearity = 0.048). Increased consumption of SSBs and ASBs is associated with risk of obesity, T2DM, hypertension, and all-cause mortality. However, the results should be interpreted cautiously because the present analyses were based on only cohort but not intervention studies.

Ordered Micro/Nanostructures with Geometric Gradient: From Integrated Wettability "Library" to Anisotropic Wetting Surface.

Geometric gradients within ordered micro/nanostructures exhibit unique wetting properties. Well-defined and ordered microsphere arrays with geometric gradient (OMAGG) are successfully fabricated through combining colloidal lithography and inclined reactive ion etching (RIE). During the inclined RIE, the graded etching rates in vertical direction of etcher chamber are the key to generating a geometric gradient. The OMAGG can be used as an effective mask for the preparation of micro/nanostructure arrays with geometric gradient by selective RIE. Through this strategy, a well-defined wettability "library" with graded silicon cone arrays is fabricated, and the possibility of screening one desired "book" from the designated wettability "library" is demonstrated. Meanwhile, the silicon cone arrays with geometric gradient (SCAGG) can be applied to control the wetting behavior of water after being modified by hydrophilic or hydrophobic chemical groups. Based on this result, a temperature-responsive wetting substrate is fabricated by modifying poly n-isopropyl acrylamide (PNIPAM) on the SCAGG. These wettability gradients have great potential in tissue engineering, microfluidic devices, and integrated sensors.

Highly Transparent, Conductive, and Bendable Ag Nanowire Electrodes with Enhanced Mechanical Stability Based on Polyelectrolyte Adhesive Layer.

In this paper, a highly transparent, conductive, and bendable Ag nanowire (AgNW)-based electrode with excellent mechanical stability was prepared through the introduction of an adhesive polyelectrolyte multilayer between AgNW networks and a polyethylene terephthalate (PET) substrate. The introduction of the adhesive layer was performed based on a peel-assembly-transfer procedure, and the adhesive polyelectrolyte greatly improved the mechanical stability of the AgNW transparent conductive films (TCFs) without obviously attenuating the morphology and optoelectrical properties of the AgNW networks. The as-prepared AgNW TCFs simultaneously possess high optical transparency, good conductivity, excellent flexibility, and remarkable mechanical stability. It is believed that the proposed strategy would pave a new way for preparing flexible transparent electrodes with a long-term stability, which is significant in the development and practical applications of flexible transparent electronic devices operated in severe environments.

Unidirectional Wetting of Liquids on "Janus" Nanostructure Arrays under Various Media.

We report the unidirectional wetting behavior of liquids (water and oil) on Janus silicon cylinder arrays (Si-CAs) under various media (air, water, and oil). The Janus cylinders were prepared by chemical modification of nanocylinders with different molecules on two sides. Through adjusting surface energies of the modified molecules, the as-prepared surfaces could control the wetting behavior of different types of liquids under various media. We discuss the regularity systematically and propose a strategy for preparing anisotropic wetting surfaces under arbitrary media. That is, to find two surface modification molecules with different surface energies, one of the molecules is easy to be wetted by the liquid under the corresponding media, while the other one is difficult. Additionally, by introducing thermal-responsive polymer brushes onto one part of Janus Si-CAs, the surfaces show thermal-responsive anisotropic wetting property under various media. We believe that due to the excellent unidirectional wettability under various media, the Janus surfaces could be applied in water/oil transportation, oil-repellent and self-cleaning coatings, water/oil separation, microfluidics, and so on.

Approach to Fabricating a Compact Gold Nanoparticle Film with the Assistance of a Surfactant.

We report a facile method to fabricate a compact Au nanoparticle film with the assistance of surfactants. First, the dodecanethiol-coated Au nanoparticles were floated on the surface of the toluene/acetonitrile solvent mixture and adjusted to an expanded dispersion by changing the mixture ratio. Silicone oil was then added as a surfactant to compress the floating nanoparticles from the original loose status to a closely packed arrangement that produced a compact nanoparticle film. The relationship of the compressed film area to the silicone oil concentration was plotted and compared to the surface tension curve of silicone oil. The results were quite consistent, suggesting that the surface location of the surfactant induced the nanoparticles' compression. The resulting nanoparticle film was uniform and sufficiently robust to be transferred to the solid substrate. Moreover, it could be applied to catalyze the reduction of 4-nitrophenol. Our study indicated that the utilization of surfactants to compress the well-dispersed nanoparticles on the liquid surface is a simple, fast, and adaptable method of fabricateing compact nanoparticle films with great promise for future applications.

Fabrication of Metal-Organic Framework and Infinite Coordination Polymer Nanosheets by the Spray Technique.

We have developed a rapid and convenient method for fabricating metal-organic framework (MOF) and infinite coordination polymer (ICP) nanosheets by spraying the atomized solution of metal ions onto the organic ligand solution. Nanosheet formation could be attributed to the anisotropic diffusion of metal ions in the ligand solution, which may give rise to a lateral interface of metal ions and organic ligands, where the crystals tend to grow laterally in the form of nanosheets. Three kinds of Zn- and Cu-based MOF nanosheets and two kinds of Co-based ICP nanosheets have been successfully obtained by spraying under mild conditions. The two-dimensional structures of nanosheets with a nanometer thickness and a homogeneous size can be evidenced by scanning electron microscopy, atomic force microscopy, X-ray diffraction, Brunauer-Emmett-Teller, and Fourier transform infrared spectroscopy measurements. Furthermore, the fabricated ICP nanosheets have exhibited efficient catalytic performance for the conversion of CO2 to high-value-added chemicals. This spray technique simplifies the nanosheet production process by industrialized means and enhances its controllability by the fast liquid-liquid interfacial fabrication, thus allowing access to the industrialized fabrication of MOF and ICP nanosheets.

Optimally designed gold nanorattles with strong built-in hotspots and weak polarization dependence.

Localized electromagnetic fields generated by interparticle plasmon coupling suffer greatly from nonreproducibility because they are extremely sensitive to the nanoparticle aggregation status and the incident polarization. Here, we synthesize gold nanorattles that exhibit inherent aggregation-insensitive hotspots due to the intraparticle core-shell plasmon coupling, and investigate the structural effect on the intraparticle coupling strength and its polarization dependence. Through optimizing the structural parameters, we successfully synthesize gold nanorattles with strong built-in hotspots and weak polarization dependence. These aggregation-insensitive and weakly polarization-dependent hotspots make the Raman enhancement from nanorattle aggregates show an unusual weak dependence on the particle aggregation status, which therefore affords the opportunity to fabricate uniform and reproducible surface enhanced Raman scattering substrates.

Controlling flow behavior of water in microfluidics with a chemically patterned anisotropic wetting surface.

We report the flow behavior of water in microfluidic systems based on a chemically patterned anisotropic wetting surface. When water flows inside a microchannel on top of a micropatterned surface with alternating hydrophilic/hydrophobic stripes, it exhibits an anisotropic flowing characteristic owing to the anisotropic wettability; thus, the patterned surface acts as a microvalve for the microfluidic system. The anisotropic flow of water is influenced by the microscale features of the patterns and the dimensions of the microchannels. Furthermore, by reasonably combining the patterned surface and microchannel together, we realize the transportation of water in a microchannel along a "virtual" wall, which is the boundary of the hydrophilic and hydrophobic area. We believe that the chemically patterned surfaces could be an alternative strategy to control the flow behavior of water in microfluidic channels.

Responsive etalon based on PNIPAM@SiO2 composite spacer with rapid response rate and excellent repeatability for sensing application.

In this paper, we demonstrate a responsive etalon fabricated through combining colloidal lithography and surface-initiated atom-transfer radical polymerization (SI-ATRP). The responsive etalon is simply constructed with one responsive spacer sandwiched by two reflective layers, and the middle responsive spacer is constructed by grafting thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) brushes on a SiO2 nanosphere array. The etalon possesses one single interference peak in the visible region, and the interference peak changes sensitively against the concentration of the external stimulant (water vapor) or the temperature of the system, owing to the responsiveness of the PNIPAM brush. Importantly, the as-prepared etalon shows a rapid response rate and excellent stability, and it is also handy to realize the miniaturization and integration of the responsive etalon based on a conventional micro-fabrication method. These features all make the as-prepared responsive etalon an attractive candidate for future sensing applications. We believe such responsive etalons are promising for the fabrication of smart photonic materials and optical sensors that may be useful in tissue engineering, medical diagnosis, public security, and biochip areas.

Thermal annealing: a facile way of conferring responsivity to inert alkyl-chain-passivated nanoparticle arrays.

This work demonstrates a facile post-treatment strategy, vacuum thermal annealing, to fabricate a dodecanethiol-passivated gold nanoparticle (Au NP) array with organic solvent sensitivity. Through investigating the structure change of the Au NP array, it was found that the interparticle distance decreased during vacuum heat treatment, which meant a closer arrangement of the particles and a more dense packing of the dodecanethiol ligands in the interparticle region. The condensation would increase the interaction of the alkyl chain and enhance their interdigitation. Furthermore, on the basis of the stretching of the alkyl chains in organic solvents, the thermally treated Au NP array showed a good response to organic solvent or vapor by using the interdigitated dodecanethiol network as its responsive unit. The alkyl chains stretch to different extents in different organic solvents, leading to differences in interparticle distance, which provided a distinct blue shift of maximum wavelength upon exposure to various organic solvents or vapors. All of these results indicated that thermal annealing was an efficient way to confer responsivity to inert Au NP arrays. Together with the cost-effectiveness of such NP arrays, this study has potential in the development of economical sensors for medical diagnostics, food safety screening, and environmental pollution monitoring.