Self-Catalyzed Synthesis of Length-Controlled One-Dimensional Nickel Oxide@N-Doped Porous Carbon Nanostructures from Metal Ion Modified Nitrogen Heterocycles for Efficient Lithium Storage.

Transition metal oxides with the merits of high theoretical capacities, natural abundance, low cost, and environmental benignity have been regarded as a promising anodic material for lithium ion batteries (LIBs). However, the severe volume expansion upon cycling and poor conductivity limit their cycling stability and rate capability. To address this issue, NiO embedded and N-doped porous carbon nanorods (NiO@NCNR) and nanotubes (NiO@NCNT) are synthesized by the metal-catalyzed graphitization and nitridization of monocrystalline Ni(II)-triazole coordinated framework and Ni(II)/melamine mixture, respectively, and the following oxidation in air. When applied as an anodic material for LIBs, the NiO@NCNR and NiO@NCNT hybrids exhibit a decent capacity of 895/832 mA h g-1 at 100 mA g-1, high rate capability of 484/467 mA h g-1 at 5.0 A g-1, and good long-term cycling stability of 663/634 mA h g-1 at 600th cycle at 1 A g-1, which are much better than those of NiO@carbon black (CB) control sample (701, 214, and 223 mA h g-1). The remarkable electrochemical properties benefit from the advanced nanoarchitecture of NiO@NCNR and NiO@NCNT, which offers a length-controlled one-dimensional porous carbon nanoarchitecture for effective e-/Li+ transport, affords a flexible carbon skeleton for spatial confinement, and forms abundant nanocavities for stress buffering and structure reinforcement during discharge/charging processes. The rational structural design and synthesis may pave a way for exploring advanced metal oxide based anodic materials for next-generation LIBs.

Interpretable Model Based on Pyramid Scene Parsing Features for Brain Tumor MRI Image Segmentation.

Due to the black box model nature of convolutional neural networks, computer-aided diagnosis methods based on depth learning are usually poorly interpretable. Therefore, the diagnosis results obtained by these unexplained methods are difficult to gain the trust of patients and doctors, which limits their application in the medical field. To solve this problem, an interpretable depth learning image segmentation framework is proposed in this paper for processing brain tumor magnetic resonance images. A gradient-based class activation mapping method is introduced into the segmentation model based on pyramid structure to visually explain it. The pyramid structure constructs global context information with features after multiple pooling layers to improve image segmentation performance. Therefore, class activation mapping is used to visualize the features concerned by each layer of pyramid structure and realize the interpretation of PSPNet. After training and testing the model on the public dataset BraTS2018, several sets of visualization results were obtained. By analyzing these visualization results, the effectiveness of pyramid structure in brain tumor segmentation task is proved, and some improvements are made to the structure of pyramid model based on the shortcomings of the model shown in the visualization results. In summary, the interpretable brain tumor image segmentation method proposed in this paper can well explain the role of pyramid structure in brain tumor image segmentation, which provides a certain idea for the application of interpretable method in brain tumor segmentation and has certain practical value for the evaluation and optimization of brain tumor segmentation model.

Accelerating Monte Carlo simulation of light propagation in tissue mimicking turbid medium based on generative adversarial networks.

PURPOSE: Monte Carlo (MC) simulation is the most frequently used method to numerically model the light propagation in biological tissues because of its high flexibility and precision. Although MC simulation is assumed to be capable of achieving any desired precision, larger number of photons are always necessary for more precise simulation, leading to its major limitation of intensive computation. In this work, the authors present a way to adapt generative adversarial networks (GAN) to accelerate MC simulation. METHODS: The pix2pix network, a variant of GAN, was investigated to reconstruct precise MC simulation results from the results roughly modeled by small amount of photons, thus the computation time was expected to be significantly saved. The proposed method was tested on single-layer embedded tumor models to derive the absorption distribution maps. RESULTS: The results demonstrate that the absorption distribution maps reconstructed from the simulation of only 10 000 photons were very similar to those modeled by using 1 000 000 photons, based on the criterion of peak signal to noise ratio (PSNR) and percentage difference of power coupling efficiencies, and the simulation process was proved to be accelerated by approximately 102 times. CONCLUSIONS: For the first time, GAN was adapted to save computation time of MC simulation of light propagation. By achieving MC simulation with acceptable quality, the proposed method can speed up the computation by hundreds of times.

FPGA implementation of a real-time digital pulse processing analysis for radiation detectors.

A new universal, flexible firmware has been implemented on field -programmable gate array (FPGA) for gamma-ray spectroscopy. The firmware of the FPGA runs on a digitizer that we developed ourselves. The present paper describes the detailed architecture of the firmware, including the trapezoidal shaper, peak detection, pulse height analyzer, and pile-up rejection. Gamma-ray spectroscopy measurements are made using a NaI(Tl) detector, CdZnTe detector, and HPGe detector.

CtBP modulates Snail-mediated tumor invasion in Drosophila.

Cancer is one of the most fatal diseases that threaten human health, whereas more than 90% mortality of cancer patients is caused by tumor metastasis, rather than the growth of primary tumors. Thus, how to effectively control or even reverse the migration of tumor cells is of great significance for cancer therapy. CtBP, a transcriptional cofactor displaying high expression in a variety of human cancers, has become one of the main targets for cancer prediction, diagnosis, and treatment. The roles of CtBP in promoting tumorigenesis have been well studied in vitro, mostly based on gain-of-function, while its physiological functions in tumor invasion and the underlying mechanism remain largely elusive. Snail (Sna) is a well-known transcription factor involved in epithelial-to-mesenchymal transition (EMT) and tumor invasion, yet the mechanism that regulates Sna activity has not been fully understood. Using Drosophila as a model organism, we found that depletion of CtBP or snail (sna) suppressed RasV12/lgl-/--triggered tumor growth and invasion, and disrupted cell polarity-induced invasive cell migration. In addition, loss of CtBP inhibits RasV12/Sna-induced tumor invasion and Sna-mediated invasive cell migration. Furthermore, both CtBP and Sna are physiologically required for developmental cell migration during thorax closure. Finally, Sna activates the JNK signaling and promotes JNK-dependent cell invasion. Given that CtBP physically interacts with Sna, our data suggest that CtBP and Sna may form a transcriptional complex that regulates JNK-dependent tumor invasion and cell migration in vivo.

Cadmium concentration and its typical input and output fluxes in agricultural soil downstream of a heavy metal sewage irrigation area.

Heavy metal pollution of agricultural soils in sewage irrigation areas is a serious environmental issue. Many prior studies have demonstrated that soil around the irrigation area is polluted with heavy metals, even though they had not been irrigated by wastewater. In this study, a paddy field downstream of the Zhangshi Irrigation Area was selected as the study area. The Cd concentrations and their representative input and output fluxes to and from the topsoil were systematically studied. The results showed that 95.5% of soil samples exceeded the screening value of Cd concentration. The Cd input fluxes via irrigation water and atmospheric deposition, accounting for 56.95% and 42.53% of the total input flux, respectively, were the main sources of Cd in soil. Crop harvesting was the main output pathway, accounting for 89.63% of the total output flux. An estimation of the annual mass balance showed that Cd in the studied area was in a state of accumulation, and the annual increase in Cd concentration in topsoil would be 2.46 µg kg-1 if the observed fluxes remain. These results will provide a reference for the development of strategies to control and reduce heavy metal contamination and diffusion in agricultural soils around irrigation areas.

2D optically controlled radio frequency orbital angular momentum beam steering system based on a dual-parallel Mach-Zehnder modulator.

An optically controlled system for generating and continuously steering radio frequency (RF) signals with double orbital angular momentum (OAM) modes is proposed and experimentally demonstrated. The optical carrier's utilization efficiency can be doubled through the distinct electro-optical modulation, which is based on two single-sideband modulation operations on a single optical carrier through a customized dual-parallel Mach-Zehnder modulator. A constructive antenna phase feeding method of a circular antenna array for collectively forming and steering an OAM radio beam is proposed and illustrated. A proof-of-concept experiment is conducted to generate and steer a dual-mode RF-OAM beam to two different two-dimensional (2D) directions, independently and simultaneously. One 17 GHz OAM beam with mode L=1 is continuously steered to 2D directions (:, 0°, 0°), (:, 0°, 1.70°), (:, 0°, 3.87°), (:, 0°, 6.17°), and(:, 0°, 7.80°), with vortex properties, where ":" means "any value of." Meanwhile, the 19 GHz OAM beam with mode L=-1 carried is steered from (:, 0°, 0°) to (:, 0°, -6.72°), and the constellations are obtained successfully.

Measurement of the rotational Doppler frequency shift of a spinning object using a radio frequency orbital angular momentum beam.

An indirect approach based on phase measurement is proposed to measure the rotational Doppler frequency shift, which takes full advantage of the phase structure of orbital angular momentum (OAM) beams in radio domain, using a vector network analyzer (VNA) as a phase discriminator. A proof-of-concept experiment is established by an optical-controlled system with the OAM state of 1. By analyzing the experiment's results, the rotational Doppler frequency shift is measured as 24.83 Hz (max error rate 0.67%) at 50π rad/s rotational velocity, deducing the rotational velocity as 50.18π (average error rate 0.36%).

Direct Dry-Grinding Synthesis of Monodisperse Lipophilic CuS Nanoparticles.

Copper sulfide nanoparticles, effective absorbers of near-infrared light, are recently attracting broad interest as a photothermal coupling agent for cancer therapy. Lipophilic copper sulfide nanoparticles are preferred for high performance biomedical applications due to high tissue affinity. Synthesis of lipophilic copper sulfide nanoparticles requires complicated multi-step processes under severe conditions. Here, we describe a new synthetic process, developed by direct dry-grinding of copper(II) acetylacetonate with sulfur under ambient environment at low temperature. The formed CuS nanoparticles are of uniform size, ~10 nm in diameter, and are monodispersed in chloroform. Each covellite CuS nanocrystal surface is modified with oleylamine through hydrogen bonding between sulfur atoms and amine groups of oleylamine. The nanoparticles demonstrate near-infrared light absorption for photothermal applications. The synthetic methodology described here is more convenient and less extreme than previous methods, and should thus greatly facilitate the preparation of photothermal lipophilic copper sulfide nanomaterials for cancer therapy.

Purification and identification of antioxidant peptides from egg white protein hydrolysate.

Egg white proteins were hydrolysed separately using five different proteases to obtain antioxidant peptides. The antioxidant activity of egg white protein hydrolysates was influenced by the time of hydrolysis and the type of enzyme. Of the various hydrolysates produced, papain hydrolysate obtained by 3-h hydrolysis (PEWPH) displayed the highest DPPH radical scavenging activity. PEWPH could also quench the superoxide anion and hydroxyl radicals, effectively inhibit lipid peroxidation and exhibit reducing power. Then, PEWPH was purified sequentially by ultrafiltration, gel filtration, RP-HPLC and two fractions with relatively strong antioxidant activity were subsequently subjected to LC-MS/MS for peptide sequence identification. The sequences of the two antioxidant peptides were identified to be Tyr-Leu-Gly-Ala-Lys (551.54 Da) and Gly-Gly-Leu-Glu-Pro-Ile-Asn-Phe-Gln (974.55 Da), and they were identified for the first time from food-derived protein hydrolysates. Last, the two purified peptides were synthesized and they showed 7.48- and 6.02-fold higher DPPH radical scavenging activity compared with the crude PEWPH, respectively. These results indicate that PEWPH and/or its isolated peptides may be useful ingredients in food and nutraceutical applications.