Optimization of metamaterials and metamaterial-microcavity based on deep neural networks.

Computational inverse-design and forward prediction approaches provide promising pathways for on-demand nanophotonics. Here, we use a deep-learning method to optimize the design of split-ring metamaterials and metamaterial-microcavities. Once the deep neural network is trained, it can predict the optical response of the split-ring metamaterial in a second which is much faster than conventional simulation methods. The pretrained neural network can also be used for the inverse design of split-ring metamaterials and metamaterial-microcavities. We use this method for the design of the metamaterial-microcavity with the absorptance peak at 1310 nm. Experimental results verified that the deep-learning method is a fast, robust, and accurate method for designing metamaterials with complex nanostructures.

Effect of indium doping on motions of 〈a〉-prismatic edge dislocations in wurtzite gallium nitride.

The influences of indium doping on dynamics of 〈a〉-prismatic edge dislocation along [Formula: see text] shuffle plane in wurtzite GaN have been investigated employing classical molecular dynamics (MD) simulations. The dependence of dislocation motion mode and dislocation velocity on indium doping concentration, temperature, and applied shear stress was clarified. Moreover, the simulation results were further analyzed using elastic theory of dislocation and thermal activation theory of dislocation motion, showing excellent agreement with the simulation. Our findings help gain deep insights into modifying dynamic behaviors of TDs through the alloying doping and offer generic tools to the study of other wurtzite materials of promising application prospects, such as AlGaN and ZnO.

Dynamic control of transverse magnetization spot arrays.

We propose a feasible strategy for firstly constructing diffraction-limited light-induced magnetization spot arrays capable of dynamically controlling transverse polarization orientation of each spot. To achieve this goal, we subtly design a tailored incident light comprised of two sorts of beams and sufficiently demonstrate tit's production through phase modulation of a radially polarized beam. Via tightly focusing counter-propagating composite illuminating beams in a 4π optical microscopic configuration, two orthogonally polarized focal fields with π/2 phase difference between them are formed, inducing a three-dimensional (3D) super-resolved transverse magnetization spot in the magnetic-optical (MO) film. Exploiting the ideal of the multi-zone plate (MZP) filter, we further achieve versatile magnetization spot arrays with controllable in-plane polarization direction in each spot. Such well-defined magnetization behavior is attributed to not merely the coherent interference of vectorial optical waves, but also non-overlapping superposition of localized focal fields. Our achievable outcomes pave the way for practical applications in spintronics and multi-value MO parallelized storage.

A simplified high figure-of-merit prism-free surface plasmon resonance refractive index sensor based on self adaptive angular interrogation.

We propose a simplified prism-free surface plasmon resonance (SPR) refractive index sensor based on self adaptive angular interrogation. An orthogonal V-shaped box with liquid sample is designed to achieve the functions of prism, sample cell, and mirror in a single setup. The rotator taking the self adaptive sample box is the sole mobile part in the system, which simplifies the structure greatly. A glass slide coated with Ag film is employed in this sample box as the sensing chip, in which the Ag film is isolated from the sample and air to prevent oxidation and pollution. According to the experimental results, the system can attain the figure-of-merit with 312.3/RIU, which is almost triple as high as that of the conventional prism-based sensor with the same samples. The proposed configuration could also be potentially utilized for the microminiaturization of the SPR sensor.

Strategy to enhance the anticancer efficacy of X-ray radiotherapy in melanoma cells by platinum complexes, the role of ROS-mediated signaling pathways.

Radiotherapy plays an important role in treatment of cancers with low toxicity to the surrounding normal tissues. However, it still fails to eradicate hypoxic tumors due to the occurrence of radioresistance. Therefore, the search for new radiation sensitizers is of great significance. Platinum (Pt) complexes have been identified as potential radiation sensitizers to increase the sensitivity of cancer cells to radiotherapy. In the present study, we have synthesized four Pt complexes containing (2 - benzimidazole [4, 5-f] - [1, 10] phenanthroline) ligand and found that they could effectively enhance the X-ray-induced growth inhibition against A375 human melanoma cells through induction of G2/M cell cycle arrest. In contrast, they showed much lower cytotoxicity toward human normal cells. The complexes also dramatically inhibited the TrxR activity and caused intracellular ROS overproduction, due to the Auger electron effect of heavy metal element under X-ray radiation. Excessive ROS triggered DNA damage and activated downstream signaling pathways, including the phosphorylation of p53 and p38MAPK, and down-regulation of phosphorylated AKT and ERK, finally resulted in increase of radiosensitivity and inhibition of tumor reproduction. Taken together, our results suggest that the synthetic Pt complexes could be further developed as sensitizers of X-ray radiotherapy.

Sensitization of cancer cells to radiation by selenadiazole derivatives by regulation of ROS-mediated DNA damage and ERK and AKT pathways.

X-ray-based radiotherapy represents one of the most effective ways in treating human cancers. However, radioresistance and side effect remain as the most challenging issue. This study describes the design and application of novel selenadiazole derivatives as radiotherapy sensitizers to enhance X-ray-induced inhibitory effects on A375 human melanoma and Hela human cervical carcinoma cells. The results showed that, pretreatment of the cells with selenadiazole derivatives dramatically enhance X-ray-induced growth inhibition and colony formation. Flow cytometry analysis indicates that the sensitization by selenadiazole derivatives was mainly caused by induction of G2/M cell cycle arrest. Results of Western blotting demonstrated that the combined treatment-induced A375 cells growth inhibition was achieved by triggering reactive oxygen species-mediated DNA damage involving inactivation of AKT and MAPKs. Further investigation revealed that selenadiazole derivative in combination with X-ray could synergistically inhibit the activity of thioredoxin reductase-1 in A375 cells. Taken together, these results suggest that selenadiazole derivatives can act as novel radiosensitizer with potential application in combating human cancers.

Dinuclear zinc(II) complexes containing (benzimidazol-2-yl)benzene that overcome drug resistance in hepatocellular carcinoma cells through induction of mitochondria fragmentation.

Herein we demonstrated that dinuclear zinc complexes could overcome drug resistance in R-HepG2 drug resistance hepatocellular carcinoma cells through induction of mitochondria-mediated apoptosis or by triggering mitochondria fragmentation, depletion of the membrane potential and intracellular ATP levels.

Theoretical prediction of impurity effects on the internally oxidized metal/oxide interface: the case study of S on Cu/Al2O3.

A detrimental sulfur effect on adhesion is known for iron- and nickel-oxide interfaces, but has never been reported on copper-oxide interfaces. Here we present a first-principles based study on the effects of temperature, interfacial stoichiometry, Al activity, and S segregation on the internally oxidized Cu/α-Al(2)O(3) interface. The calculated "interfacial phase diagram" for temperatures of interest suggests that the equilibrium interface structure is near the transition between Al-rich and stoichiometric phases. The Al-rich type interface is significantly stronger than the stoichiometric counterpart. The S effect on the Cu/α-Al(2)O(3) interface is obvious: S strongly segregates to both types of interface, degrades the adhesion (by ∼65%) and also reduces the size stability of alumina particles in Cu.