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We implement the machine-learning-assisted (MLA) method to predict the long-term stability of Solid Oxide Fuel Cell (SOFC) cathodes under the influence of Cr poisoning.

The rational design of high-performance catalysts is hindered by the lack of knowledge of the structures of active sites and the reaction pathways under reaction conditions, which can be ideally addressed by an in situ/operando characterization. Besides the experimental insights, a theoretical investigation that simulates reaction conditions—so-called operando modeling—is necessary for a plausible understanding of a working catalyst system at the atomic scale. However, there is still a huge gap between the current widely used computational model and the concept of operando modeling, which should be achieved through multiscale computational modeling. This Perspective describes various modeling approaches and machine learning techniques that step toward operando modeling, followed by selected experimental examples that present an operando understanding in the thermo- and electrocatalytic processes. At last, the remaining challenges in this area are outlined.

Cerium oxide-based nanozymes have recently drawn much attention in the field of biomedical and antioxidant applications, because of their unique regenerative or autocatalytic properties. Herein, we studied the biomimetic superoxide dismutase (SOD) nanozymes CeO2-Gd that combines the fluorescence properties of rare earth Gd with the antioxidant properties of CeO2 nanoparticles, which was prepared via facile route. The structure and composition of the CeO2-Gd were measured and verified by X-ray powder diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray electron spectroscopy (XPS). Confocal microscopy was used to image cells. Antioxidant performance and cell viability of these nanozymes were measured in vitro using BGC-803 cell. CeO2-Gd nanozymes with a higher Ce3+/Ce4+ ratio show higher superoxide dismutase (SOD) mimetic activity. Their antioxidant activity and fluorescence properties of CeO2-Gd in BGC-803 cancer cells are enhanced by oxygen vacancies generated by doping rare-earth elements Gd. This work may guide the future design of CeO2-Gd-based biomimetic nanozymes for anticancer and antioxidant applications.

BACKGROUND: Poor prognosis is common in gastric cancer patients due to multidrug resistance (MDR)-induced recurrence and metastasis. In the present study, we investigated the expression of microRNA (miR)-200c in gastric cancer tissues and cell lines and its relationship with the expression of the drug resistant gene ABCB1, which encodes P-glycoprotein (P-gp). METHODS: The basic characteristics of 102 patients with gastric cancer were reviewed. Real time-polymerase chain reaction (PCR), immunohistochemistry, and Western blot were employed to detect the expression levels of miR-200c and P-gp in gastric carcinoma tissues and cell lines. The correlation of miR-200c messenger RNA (mRNA) level with clinicopathological characteristics and P-gp protein expression were analyzed. SGC7901/vincristine (VCR) cells were transfected with miR-200c mimics or a specific small interfering RNA (siRNA) targeting the ABCB1 gene. The methyl thiazolyl tetrazolium (MTT) assay and flow cytometry were used to determine the role of miR-200c and ABCB1 on the viability and apoptosis of gastric carcinoma cell lines. RESULTS: The level of miR-200c in carcinoma tissues was significantly lower than that in adjacent tissues, and the expression level of P-gp in carcinoma tissues was obviously higher than that in adjacent tissues (P

Selective deconstructive functionalization of alkenes, other than the well-established olefin metathesis and ozonolysis, to produce densely functionalized molecular scaffolds is highly attractive but challenging. Here we report an efficient photo-mediated deconstructive germinal dihalogenation of carbon-carbon double bonds. A wide range of geminal diiodoalkanes and bromo(iodo)alkanes (>40 examples) are directly prepared from various trisubstituted alkenes, including both cyclic and acyclic olefins. This C=C cleavage is highly chemoselective and produces geminal dihalide ketones in good yields. Mechanistic investigations suggest a formation of alkyl hypoiodites from benzyl alcohols and N-iodoimides, which undergo light-induced homolytic cleavage to generate active oxygen radical species., Efficient synthetic pathways to geminal dihalides are quite limited, despite their versatility as chemical building blocks. Here, the authors report a photo-mediated deconstructive fragmentation of cyclic and acyclic trisubstituted alkenes to access a variety of geminal dihalides.

Deuterium labelled compounds are of significant importance in chemical mechanism investigations, mass spectrometric studies, diagnoses of drug metabolisms, and pharmaceutical discovery. Herein, we report an efficient hydrogen deuterium exchange reaction using deuterium oxide (D2O) as the deuterium source, enabled by merging a tetra-n-butylammonium decatungstate (TBADT) hydrogen atom transfer photocatalyst and a thiol catalyst under light irradiation at 390 nm. This deuteration protocol is effective with formyl C–H bonds and a wide range of hydridic C(sp3)–H bonds (e.g. α-oxy, α-thioxy, α-amino, benzylic, and unactivated tertiary C(sp3)–H bonds). It has been successfully applied to the high incorporation of deuterium in 38 feedstock chemicals, 15 pharmaceutical compounds, and 6 drug precursors. Sequential deuteration between formyl C–H bonds of aldehydes and other activated hydridic C(sp3)–H bonds can be achieved in a selective manner., A selective hydrogen deuterium exchange reaction with formyl C–H bonds and a wide range of hydridic C(sp3)–H bonds has been achieved by merging tetra-n-butylammonium decatungstate photocatalyst and a thiol catalyst under 390 nm light irradiation.

Summary Polarity-reversal catalysts enable otherwise sluggish or completely ineffective reactions which are characterized by unfavorable polar effects between radicals and substrates. We herein disclose that when irradiated by visible light, bromine can behave as a polarity-reversal catalyst. Hydroacylation of vinyl arenes, a three-component cascade transformation and deuteration of aldehydes were each achieved in a metal-free manner without initiators by using inexpensive N-bromosuccinimide as the precatalyst. Light is essential to generate and maintain the active bromine radical during the reaction process. Another key to success is that HBr can behave as an effective hydrogen donor to turn over the catalytic cycles., Graphical abstract, Highlights • Using bromine as a polarity-reversal catalyst to generate acyl radicals • Additive- and metal-free, atom- and step-economic, and operationally simple process • Using constant light-irradiation to induce and maintain bromine radicals • Access carbonyl compounds and deuterated aldehydes with wide substrate scope, Chemistry; Organic chemistry; Green chemistry

Polarity-reversal catalysts enable otherwise sluggish or completely ineffective reactions which are characterized by unfavorable polar effects between radicals and substrates. We herein disclose for the first time that when irradiated by visible light, bromine can behave as a polarity-reversal catalyst. Hydroacylation of vinyl arenes, a three-component cascade transformation and deuteration of aldehydes were each achieved in a metal-free manner without initiators by using N-bromosuccinimide as the precatalyst. Light is essential to generate and maintain the active bromine radical during the reaction process. Another key to success is that HBr can behave as an effective hydrogen-donor to turn over the catalytic cycles.

A visible-light-mediated radical Smiles rearrangement has been achieved using neutral eosin Y as a direct hydrogen atom transfer (HAT) photocatalyst. Novel N-heterocycles as single diastereomers fe...

Robotic micro/nanoswimmers can potentially be used as tools for medical applications, such as drug delivery and noninvasive surgery. Recently, achiral microswimmers have gained significant attention because of their simple structures, which enables high-throughput fabrication and size scalability. Here, microparticle image velocimetry (&micro, PIV) was used to study the hydrodynamics of achiral microswimmers near a boundary. The structures of these microswimmers resemble the letter L and were fabricated using photolithography and thin-film deposition. Through &micro, PIV measurements, the velocity flow fields of the microswimmers rotating at different frequencies were observed. The results herein yield an understanding of the hydrodynamics of the L-shaped microswimmers, which will be useful in applications such as fluidic manipulation.

CeO2 nanoparticles (Ce NPs) have received considerable interest due to their unique autocatalytic property. In this paper, the autocatalytic properties of Ce NPs of three different sizes were measured in vitro using a human gastric cancer cell line (BGC-803) at different concentrations ranging from 20 ng μL−1 to 200 ng μL−1. The evaluation model of the autocatalytic properties of the Ce NPs was built by partial least squares regression (PLSR) based on the Matlab software. Multiple variable factors were quantitatively analyzed in terms of regression and correlation. The model indicated that the concentration was the primary factor, followed by the size of the Ce NPs. The autocatalytic properties of the Ce NPs was also promoted by the specific surface area, the valence states of Ce, and the surface charge in the cell culture medium. This study attempted to establish a quantitative framework and supply a new strategy for evaluating the autocatalytic property of cerium oxide nanoparticles for their use in biological and medical fields.

Enantioenriched 1,4-dicarbonyl compounds are versatile synthons in natural product and pharmaceutical drug synthesis. We herein report a mild pathway for the efficient enantioselective synthesis of these compounds directly from aldehydes through synergistic cooperation between a neutral eosin Y hydrogen atom transfer photocatalyst and a chiral rhodium Lewis acid catalyst. This method is distinguished by its operational simplicity, abundant feedstocks, atom economy, and ability to generate products in high yields (up to 99 %) and high enantioselectivity (up to 99 % ee).

A mild in situ method was developed to construct an iron doped rutile TiO2 photocatalyst like cauliflower for degradation synthetic textile dye-methyl orange. The synthesized photocatalysts presented distinguished photocatalytic activity. At the optimal Fe concentration (0.5%), the decomposition rate of methyl orange (MO) was about 90% under 40 min of ultraviolet (UV) light irradiation. Whereas, to our knowledge, only 70% of the decomposition rate of MO was achieved by commercial photocatalyst P25 under the similar reaction condition. Additionally, the rutile preparation temperature did not exceed 100 &deg, C, which was much lower than the traditional preparation calcination temperature (e.g., 600 &deg, C). The specific surface area of Fe doped catalysts was bigger than that of the control sample and the catalyst characterization indicated that the doped iron was incorporated into the rutile TiO2 lattice and resulted in the lattice disorder. The lattice disorder would have generated surface defects in the crystal structure, which was in favor of the photocatalytic reaction. The UV-Vis diffuse refection characterization and Density Functional Theory (DFT) calculation suggested that doping a small amount of Fe into the lattice of rutile would lead to a narrower band gap and the formation of a doping energy level between conduction and valence bands of TiO2. This further increased the degradation efficiency of synthetic textile dyes in wastewaters. Our study has provided a relatively easy operation for synthesis Fe doped rutile TiO2, which is a benefit to decrease the cost in wastewater treatment process.

As a new antioxidant, nanoceria is of significant importance in applications of medical and biological fields. In comparison with conventional organic antioxidants, nanoceria has multienzyme mimetic activity by Ce4+/Ce3+ redox cycle. This unique regenerative/autocatalytic property has been widely used in the aspects of free-radical scavenger, radiation protection, oxidative-stress-related disease, drug delivery, biosensor, tissue engineering, cancer biomarker, and anti-inflammatory. This paper reviews the latest breakthrough of nanoceria as an antioxidant in applications of medical and biological fields on the base of the authors’ research works on resistance to oxidation and cytotoxicity. The challenges of nanoceria encountered in applications in medical and biological fields are commented as well.

With the increased power of optoelectronic devices, enhancing thermal conductivities of transparent materials is key to thermal dissipation. Recently, our group has experimentally demonstrated a novel composite material with both high thermal conductivity and transparency by electrospinning. In this study, a numerical model was built to explore the effective thermal conductivity of the composite with non-overlapping electrospun polymer fibers and solved by the finite element method. Effects of the side length of a representative volume element and thermal conductivity along different directions of the composite were investigated by the model by adjusting the size and angle of the representative volume element. In the meanwhile, the effects of fiber volume and fiber orientation on the effective thermal conductivity were analyzed which is realized by controlling the fiber orientation with normal distribution. The generated models consisted of randomly distributed long fibers. Moreover, the overlapping methods of fiber films were studied to optimize the thermal dissipation. The electrospun composite was applied on a light emitting diode (LED) modules in a simulation way. In those modules, simulated effective thermal conductivity of the electrospun composite was applied and the temperature reduction on phosphor of the modules have been studied. This study provides a deeper understanding of effective thermal conductivity of composite that is reinforced by continuous long fibers and a useful tool to simulate the effective thermal conductivity with desired fiber volume fraction and fiber orientation.