According to the World Health Organization, the air pollution is a serious problem that threatens the human health and the environmental balance. The goal of this paper is to study the on-line ...detection of the air pollution augmentation by monitoring the level of the micro particles concentrations in the outdoor air. The proposed statistical approach is tested by using the real PM10 pollution data, which are provided by the air monitoring stations located in Strasbourg. First, an autoregressive model with exogenous variables is designed to describe the PM10 concentrations of several stations. Next, a special sequential change detection test is used to detect a transient change in the PM10 concentrations. Two versions of this test are proposed: the centralized Finite Moving Average (FMA) test and the decentralized FMA test. The criterion is based on the minimization of the missed detection probability provided that the false alarm rate is upper bounded. The theoretical analysis and the comparison of the proposed approaches on real data are discussed.
Angelman syndrome (AS) patients often respond to low glycemic index therapy to manage refractory seizures. These diets significantly affect quality of life and are challenging to implement. These ...formulations may have benefits in AS even in the absence of biomarkers suggesting ketosis.
We aimed to compare an exogenous medical food ketone formulation (KF) with placebo for the dietary management of AS.
This randomized, double-blind, placebo-controlled, crossover clinical trial was conducted in an academic center from 15 November, 2018 to 6 January, 2020. Thirteen participants with molecularly confirmed AS aged 4–11 y met the criteria and completed the 16-wk study. The study consisted of four 4-wk phases: a baseline phase, a blinded KF or placebo phase, a washout phase, and the crossover phase with alternate blinded KF or placebo. Primary outcomes were safety and tolerability rated by retention in the study and adherence to the formulation. Additional secondary outcomes of safety in this nonverbal population included blood chemistry, gastrointestinal health, seizure burden, cortical irritability, cognition, mobility, sleep, and developmental staging.
Data were compared between the baseline, KF, and placebo epochs. One participant exited the trial owing to difficulty consuming the formulation. Adverse events included an increase in cholesterol in 1 subject when consuming KF and a decrease in albumin in 1 subject when consuming placebo. Stool consistency improved with KF consumption, from 6.04 ± 1.61 at baseline and 6.35 ± 1.55 during placebo to 4.54 ± 1.19 during KF (P = 0.0027). Electroencephalograph trends showed a decrease in Δ frequency power during the KF arm and event-related potentials suggested a change in the frontal memory response. Vineland-3 showed improved fine motor skills in the KF arm.
The exogenous KF appears safe. More data are needed to determine the utility of exogenous ketones as a nutritional approach in children with AS. This trial was registered at clinicaltrials.gov as NCT03644693.
The use of optically controlled vapor bubbles for controlled synthesis and deposition at interfaces is a promising emerging technique, which is intrinsically limited by the ability of the system to ...provide enough heat for bubble formation that is typically addressed using a plasmonic substrate. Herein, a simple and fast method for laser-controlled printing of plasmonic nanoparticles onto nonplasmonic substrates is shown. The laser fluence needed to print the nanoparticle was lowest for nanoparticles in resonance with the laser wavelength, but the technique is also effective off-resonance. Hierarchical assemblies were obtained, where melting was observed up to a micron from the focal point of the laser beam. The assemblies show plasmonic properties in the unmelted region, as shown by surface-enhanced Raman scattering spectroscopy measurements. This work will lead to future studies on controlling the hierarchical structure of nanoparticle assemblies formed at the bubble interface toward applications in sensing and devices.
Layered rare-earth hydroxides (LREH, RE = Y, Eu) were employed as a host material to construct hybrid systems together with an N-substituted naphthalene diimide sulfonate (NDI-SO3). The initial ...emission spectrum of NDI-SO3 in the presence of LYH displayed a green emission (513 nm) arising from the NDI-SO3 excimer-type state. After 30 min, the excimer-type state disappeared and a J-type aggregate was formed. Doping LYH with Ce3+ ions led to the formation of a UV-emitting material (LYH:Ce). The incorporation of NDI-SO3 in a LYH:Ce colloidal dispersion generated the same aggregate species of NDI-SO3 as LYH, and by varying the concentration of Ce3+ in LYH:Ce, suppression of the formation of emitting NDI-SO3 species was observed. Quenching followed by recovery of the fluorescence of Ce was observed upon the addition of NDI-SO3. NDI-SO3 in the presence of LEuH displayed only the emission of the monomeric form of the dye, and no aggregation was detected. NDI-SO3/LEuH were used as a donor/acceptor pair system, where quenching of NDI-SO3 and the concomitant increase of Eu3+ emission indicated efficient energy transfer between NDI and LREH. The intriguing aggregation and energy transfer between a photoactive inorganic host and organic guest offers a promising approach to achieve materials with tunable luminescence. This study encourages further studies on the preparation of new organic–inorganic hybrids, particularly toward an understanding of host–guest interactions at the interface of LREH particles. Furthermore, understanding the role of NDI aggregation on energy transfer processes at nanomaterial interfaces will advance future applications in optoelectronics, energy, and sensing.
The growth of ultrathin semiconductors is advantageous for photocatalysis due to improved photophysical properties and reduced charge recombination. Along these lines, templating the growth of ...semiconductors in confined spaces can allow control over semiconductor growth while also conferring the properties of the template to provide composite nanomaterial hybrids. Herein, the semiconductor In 2 S 3 is grown in the organically‐modified interlayer space of Ti 3 C 2 T X MXene, a versatile 2D material with metallic character and broadband light absorption. The growth of 1–2 nm thick layers of In 2 S 3 in the interlayer of MXene leads to a drastic increase in photocatalytic properties and light‐induced charge generation due to decreased interfacial charge transfer resistance. Interestingly, the hydrothermal conditions of In 2 S 3 growth lead to partial oxidation of Ti 3 C 2 T X MXene to form anatase TiO 2 nanocrystals, although this effect is strongly limited by increased In 2 S 3 precursors due to passivation of the MXene surface. MXenes serve as effective templates for the confined growth of semiconductors, emphasizing the potential of MXene as a template for 2D material heterostructures. Overall, this work further develops MXene‐based 2D material composites, offering insights into the origins of the enhanced photocatalytic and photoelectrochemical properties, toward improvements in energy production and aqueous phase catalysis.
Certain nanomaterials can filter and alter unwanted compounds due to a high surface area, surface reactivity, and microporous structure. Herein, γ-Bi2MoO6 particles are synthesized via a colloidal ...hydrothermal approach using organically modified Laponite as a template. This organically modified Laponite interlayer serves as a template promoting the growth of the bismuth molybdate crystals in the 010 direction to result in hybrid Laponite–Bi2MoO6 particles terminating predominantly in the {100} crystal facets. This resulted in an increase in particle size from lateral dimensions of <100 nm to micron scale and superior adsorption capacity compared to bismuth molybdate nanoparticles. These {100}-facet terminated particles can load both cationic and anionic dyes on their surfaces near-spontaneously and retain the photocatalytic properties of Bi2MoO6. Furthermore, dye-laden hybrid particles quickly sediment, rendering the task of particle recovery trivial. The adsorption of dyes is completed within minutes, and near-complete photocatalytic degradation of the adsorbed dye in visible light allowed recycling of these particles for multiple cycles of water decontamination. Their adsorption capacity, facile synthesis, good recycling performance, and increased product yield compared to pure bismuth molybdate make them promising materials for environmental remediation. Furthermore, this synthetic approach could be exploited for facet engineering in other Aurivillius-type perovskites and potentially other materials.
MXenes represent a novel class of 2D materials with unique properties and have great potential for diverse applications in sensing and electronics; however, their directed assembly at interfaces has ...not yet been achieved. Herein, the plasmonic heating of MXenes was exploited to achieve the controlled deposition of MXene assemblies via a laser-directed microbubble. The influence of various factors such as solvent composition, substrate surface chemistry, MXene concentration, and laser fluence was investigated, establishing the optimal conditions for rapid patterning with good fidelity. Printed MXene assemblies showed good electrical conductivity and plasmonic sensing capabilities and were able to meet or exceed the state of the art without additional postprocessing steps. This represents the first study of a directed approach for microfabrication using MXenes and lays the foundation for future work in optically directed assembly of MXenes and MXene-based nanocomposites at interfaces toward sensors and devices.
Designing nanostructures with extended light absorption via defect engineering is a useful approach for the synthesis of efficient photocatalysts. Herein, ZnIn2S4 was grown hydrothermally in the ...modified interlayer space of Laponite, resulting in lamellae consisting of Zn-defective ZnIn2S4 several unit cells thick. In the process it was found that Mg2+ leached from Laponite during synthesis led to the formation of Zn defects in ZnIn2S4. This resulted in nanohybrids with light absorption extended across the visible spectrum and in improved charge transfer due to the layered structure formed via confined growth. Compared with pure ZnIn2S4, Zn-defective ZnIn2S4-Laponite hybrids have increased photocurrent generation and photocatalytic performance. The leaching of Mg2+ and the resulting formation of Zn defects was attenuated by addition of 4 mM Mg2+ to the reaction, due to a combination of shifting of the equilibrium of Mg2+ leaching toward stability, and increased ionic strength. In summary, this work demonstrates the growth of ∼1 nm thick lamellae of ZnIn2S4, presents a unique strategy to generate cation defects in nanomaterials and the mechanism behind it, and also provides an approach to mitigate Mg2+ leaching in such syntheses.
The steady release of anthropogenic toxins into the biosphere is compromising water security globally. Herein, CoAl layered double hydroxide, a clay-like layered material with a cationic surface ...charge, was organically modified and used to template the growth of Bi2MoO6. The resulting nanohybrid selectively removed the anionic dye methyl orange from aqueous solution and showed an enhancement of greater than 300% in the maximum adsorptivity (1.95 mmol/g) compared to modified CoAl layered double hydroxide (0.42 mmol/g). Interestingly, the observed improvement in adsorption occurs without any significant increase in the surface area of the hybrids. Furthermore, these hybrids exhibit increased broadband visible light absorption, and their photoactivity is slightly improved compared to CoAl layered double hydroxide. This study demonstrates that composites of clay-like materials with Aurivillius oxides are promising sorbent materials for water decontamination and photocatalytic antifouling membranes and shows that the synthetic strategy that was first established with an anionic layered silicate nanoclay can be generalized to other ionic layered materials.
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