33 research outputs found
Crises and opportunities in terms of energy and AI technologies during the COVID-19 pandemic [Editorial]
Editorial
Click Chemistry: Mechanistic Insights into the Role of Amines Using Single-Molecule Spectroscopy
Single-molecule
spectroscopy is used to gain insights into the
click chemistry reaction photocatalyzed by copper. We show that Cu<sub><i>x</i></sub>O@Nb<sub>2</sub>O<sub>5</sub> catalysts can
act as truly heterogeneous photocatalysts and that the amine plays
an important role in the complexation between the alkyne and the copper
active site on the catalyst surface. For complex reactions occurring
in the subnanomolar range, preassociation can be essential and cocatalysts
(such as amines here) may play an enabling role facilitating the reagents
“reunion” and prolonging the time available for reaction.
This provides a rational analysis of the amine role in heterogeneous
photocatalytic click chemistry
AI-based optimization of PEM fuel cell catalyst layers for maximum power density via data-driven surrogate modeling
© 2020 Elsevier Ltd Catalyst layer (CL) is the core electrochemical reaction region of proton exchange membrane fuel cells (PEMFCs). Its composition directly determines PEMFC output performance. Existing experimental or modeling methods are still insufficient on the deep optimization of CL composition. This work develops a novel artificial intelligence (AI) framework combining a data-driven surrogate model and a stochastic optimization algorithm to achieve multi-variables global optimization for improving the maximum power density of PEMFCs. Simulation results of a three-dimensional computational fluid dynamics (CFD) PEMFC model coupled with the CL agglomerate model constitutes the database, which is then used to train the data-driven surrogate model based on Support Vector Machine (SVM), a typical AI algorithm. Prediction performance shows that the squared correlation coefficient (R-square) and mean percentage error in the test set are 0.9908 and 3.3375%, respectively. The surrogate model has demonstrated comparable accuracy to the physical model, but with much greater computation-resource efficiency: the calculation of one polarization curve will be within one second by the surrogate model, while it may cost hundreds of processor-hours by the physical CFD model. The surrogate model is then fed into a Genetic Algorithm (GA) to obtain the optimal solution of CL composition. For verification, the optimal CL composition is returned to the physical model, and the percentage error between the surrogate model predicted and physical model simulated maximum power densities under the optimal CL composition is only 1.3950%. The results indicate that the proposed framework can guide the multi-variables optimization of complex systems
Direct, Rapid, Facile Photochemical Method for Preparing Copper Nanoparticles and Copper Patterns
We develop a facile method for preparing copper nanoparticles
and
patterned surfaces with copper stripes by ultraviolet (UV) irradiation
of a mixture solution containing a photoinitiator and a copper–amine
coordination compound. The copper–amine compound is formed
by adding diethanol amine to an ethanol solution of copper chloride.
Under UV irradiation, free radicals are generated by photoinitiator
decomposition. Meanwhile, the copper–amine coordination compound
is rapidly reduced to copper particles because the formation of the
copper–amine coordination compound prevents the production
of insoluble cuprous chloride. PolyÂ(vinylpyrrolidone) is used as a
capping agent to prevent the aggregation of the as-prepared copper
nanoparticles. The capping agent increases the dispersion of copper
nanoparticles in the ethanol solution and affects their size and morphology.
Increasing the concentration of the copper–amine coordination
compound to 0.1 M directly forms a patterned surface with copper stripes
on the transparent substrate. This patterned surface is formed through
the combination of the heterogeneous nucleation of copper nanoparticles
and photolithography. We also investigate the mechanism of photoreduction
by UV–vis spectroscopy and gas chromatography–mass spectrometry
Mechanism of Interaction of Water above the Methylammonium Lead Iodide Perovskite Nanocluster: Size Effect and Water-Induced Defective States
Water is often viewed as detrimental
to organic halide perovskite
stability. However, evidence highlights its efficacy as a solvent
during organic perovskite liquid synthesis. This paradox prompts an
investigation into water’s influence on perovskite nanoclusters.
Employing first principle calculations and ab initio molecular dynamics simulations, surprisingly, we discover some subsurface
layers of methylammonium lead iodide (MAPbI3) nanoclusters
exhibit stronger relaxation than surface layers. Moreover, a strong
quantum confinement effect enhances the band gap of MAPbI3 as the nanocluster size decreases. Notably, the water molecules
above MAPbI3 nanoclusters induce rich localized defect
states, generating low-lying shallow states above the valence band
for the small amounts of surface water molecules and band-like deep
states across the whole gap for large nanoclusters. This work provides
insights into water’s role in the electronic structure and
structural evolution of perovskite nanoclusters, aiding the design
of water-resistant layers to protect perovskite quantum dots from
ambient humidity
Exotic Quartic Anharmonicity Induced by Rattling Effect in Layered Isostructural Compounds
Anharmonicity
of phonons correlates with less dispersive potential
surfaces and usually governs the thermal transport of low-dimensional
materials. Here, we demonstrate the significant role of the so-called
“rattling” action in affecting lattice anharmonicity,
originating from the ease of freedom of confined but loose atoms in
two-dimensional space. Based on calculations of X2Si2Te6 (X = Sb and Bi) within the Peierls–Boltzmann
framework, the degree of high-order four-phonon scattering differs
strikingly despite their isostructural feature. Upon switching on
four-phonon scattering, a significant drop of thermal conductivity
(Îşph) occurs in Bi2Si2Te6 up to 43.15% (71.62%) at 300 K (1000 K), while a moderate
reduction occurs for Sb2Si2Te6. This
arises from a stronger quartic anharmonicity of Bi2Si2Te6 than Sb2Si2Te6, dominated by the redistribution four-phonon process (λ +
λ′ → λ″ + λ‴). We show
that the strong quartic anharmonicity is more likely to occur in systems
with flat phonon bands, large atoms, and rattling atomic units. These
new insights provide perspectives in the design of materials with
low Îşph through introducing rattling units in layered
materials or interfaces
Additional file 2 of LINC00240 in the 6p22.1 risk locus promotes gastric cancer progression through USP10-mediated DDX21 stabilization
Additional file 2: Supplementary Figure 1. The relative expression levels of LINC00240 in human GES-1, MKN-28, MKN-45, AGS, BGC-823, HGC-27 and MGC-803 cell lines. ***P < 0.001. Supplementary Figure 2. Silencing of LINC00240 significantly promoted apoptosis of gastric cancer cells (A), but did not impact cell cycle (B). Supplementary Figure 3. Expression of apoptotic proteins (A), DDX21 and USP10 (B) in gastric cancer xenografts
Additional file 1 of LINC00240 in the 6p22.1 risk locus promotes gastric cancer progression through USP10-mediated DDX21 stabilization
Additional file 1: Supplementary Table 1. Primers for RT-qPCR. Supplementary Table 2. Sequences of shRNAs and siRNAs. Supplementary Table 3. Antibodies used in the study. Supplementary Table 4. Mass spectrometry of proteins pulled-down by LINC00240 in MGC80-3 cell
Additional file 1 of Automatic evaluation of atlantoaxial subluxation in rheumatoid arthritis by a deep learning model
Additional file 1: Sup Fig. 1. Distribution of ADI and SAC. a Atlantodental interval (ADI, mm). b Space available for the spinal cord (SAC, mm)
Unimolecular Micelle-Based Hybrid System for Perivascular Drug Delivery Produces Long-Term Efficacy for Neointima Attenuation in Rats
At present, there
are no clinical options for preventing neointima-caused
(re)Âstenosis after open surgery such as bypass surgery for treating
flow-limiting vascular disease. Perivascular drug delivery is a promising
strategy, but in translational research, it remains a major challenge
to achieve long-term (e.g., > 3 months) antiÂ(re)Âstenotic efficacy.
In this study, we engineered a unique drug delivery system consisting
of durable unimolecular micelles, formed by single multiarm star amphiphilic
block copolymers with only covalent bonds, and a thermosensitive hydrogel
formed by a polyÂ(lactide-co-glycolide)–polyÂ(ethylene glycol)–polyÂ(lactide-co-glycolide) triblock copolymer (abbreviated as triblock gel) that is stable
for about 4 weeks <i>in vitro</i>. The drug-containing unimolecular
micelles (UMs) suspended in Triblock gel were able to sustain rapamycin
release for over 4 months. Remarkably, even 3 months after perivascular
application of the rapamycin-loaded micelles in Triblock gel in the
rat model, the intimal/medial area ratio (a restenosis measure) was
still 80% inhibited compared to the control treated with empty micelle/gel
(no drug). This could not be achieved by applying rapamycin in Triblock
gel alone, which reduced the intimal/medial ratio only by 27%. In
summary, we created a new UM/Triblock gel hybrid system for perivascular
drug delivery, which produced a rare feat of 3-month restenosis inhibition
in animal tests. This system exhibits a real potential for further
translation into an antiÂ(re)Âstenotic application with open surgery