A Novel Blind Separation Method in Magnetic Resonance Images

A novel global search algorithm based method is proposed to separate MR images blindly in this paper. The key point of the method is the formulation of the new matrix which forms a generalized permutation of the original mixing matrix. Since the lowest entropy is closely associated with the smooth degree of source images, blind image separation can be formulated to an entropy minimization problem by using the property that most of neighbor pixels are smooth. A new dataset can be obtained by multiplying the mixed matrix by the inverse of the new matrix. Thus, the search technique is used to searching for the lowest entropy values of the new data. Accordingly, the separation weight vector associated with the lowest entropy values can be obtained. Compared with the conventional independent component analysis (ICA), the original signals in the proposed algorithm are not required to be independent. Simulation results on MR images are employed to further show the advantages of the proposed method

Surface passivation for highly active, selective, stable, and scalable CO2 electroreduction

Electrochemical conversion of CO2 to formic acid using Bismuth catalysts is one the most promising pathways for industrialization. However, it is still difficult to achieve high formic acid production at wide voltage intervals and industrial current densities because the Bi catalysts are often poisoned by oxygenated species. Herein, we report a Bi3S2 nanowire-ascorbic acid hybrid catalyst that simultaneously improves formic acid selectivity, activity, and stability at high applied voltages. Specifically, a more than 95% faraday efficiency was achieved for the formate formation over a wide potential range above 1.0 V and at ampere-level current densities. The observed excellent catalytic performance was attributable to a unique reconstruction mechanism to form more defective sites while the ascorbic acid layer further stabilized the defective sites by trapping the poisoning hydroxyl groups. When used in an all-solid-state reactor system, the newly developed catalyst achieved efficient production of pure formic acid over 120 hours at 50 mA cm–2 (200 mA cell current)

DeepDyve: Dynamic Verification for Deep Neural Networks

Deep neural networks (DNNs) have become one of the enabling technologies in many safety-critical applications, e.g., autonomous driving and medical image analysis. DNN systems, however, suffer from various kinds of threats, such as adversarial example attacks and fault injection attacks. While there are many defense methods proposed against maliciously crafted inputs, solutions against faults presented in the DNN system itself (e.g., parameters and calculations) are far less explored. In this paper, we develop a novel lightweight fault-tolerant solution for DNN-based systems, namely DeepDyve, which employs pre-trained neural networks that are far simpler and smaller than the original DNN for dynamic verification. The key to enabling such lightweight checking is that the smaller neural network only needs to produce approximate results for the initial task without sacrificing fault coverage much. We develop efficient and effective architecture and task exploration techniques to achieve optimized risk/overhead trade-off in DeepDyve. Experimental results show that DeepDyve can reduce 90% of the risks at around 10% overhead

Preparation of Homogeneous Nanostructures in 5 Minutes for Cancer Cells Capture

Grafting aptamers on nanostructured substrates has shown ultrasensitivity in isolation of circulating tumor cells (CTCs). Here, we report that over 80 cm2 of homogenous nanostructured surface on glass substrates can be prepared in 5 min after one-step dry etching. The surface area was doubled; the average diameter of nanostructures is approximately 374 nm, which is more close to the nanostructures of natural extracellular matrix. Antiepithelial cell adhesion molecule aptamers grafted nanostructured glass substrates captured over 76% of PC3 cells compared to 30% of planar substrates. Bispecific aptamers cofunctionalized nanostructured substrates, however, fail to capture cancer cells probably due to the formation of heterodimers. This limitation reveals that multispecific aptamers, when applied to cell isolation, must be analyzed to exclude any potential formation of heterodimers due to complementary sequence matching

Investigation of Gut Bacterial Communities of Asian Citrus Psyllid (<i>Diaphorina citri</i>) Reared on Different Host Plants

Diaphorina citri Kuwayama (Hemiptera: Liviidae) can cause severe damage to citrus plants, as it transmits Candidatus Liberibacter spp., a causative agent of Huanglongbing disease. Symbiotic bacteria play vital roles in the ecology and biology of herbivore hosts, thereby affecting host growth and adaptation. In our research, the effects of Rutaceous plants (i.e., Citrus reticulata cv. Shatangju, Citrus poonensis cv. Ponkan, Murraya paniculata (orange jasmine), Citrus limon (lemon), and Citrus sinensis (navel orange)) on the gut microbiota (GM) and microbial diversity of D. citri adults were investigated by 16S rRNA high-throughput sequencing. It was found that Proteobacteria dominated the GM communities. The gut microbe diversity was the highest in the ponkan-feeding population, and the lowest in the Shatangju-feeding population. The NMDS analysis revealed that there were obvious differences in the GM communities among the different hosts. PICRUSt function prediction indicated significant differences in host function, and those pathways were crucial for maintaining population reproduction, growth, development, and adaptation to environmental stress in D. citri. Our study sheds new light on the interactions between symbionts, herbivores, and host plants and expands our knowledge on host adaptation related to GM in D. citri

Effect of phenolic resin infiltration content on the structural and electrochemical properties of hierarchical porous carbons

Hierarchical porous (micro-, meso- and macro-porous) carbons (HPCs) are synthesized by a facile replica template method with phenolic resin (PR) as a carbon source and hollow mesoporous silica as a hard template. The morphology of the HPCs can be easily controlled by altering the mass ratio of PR to SiO2 spheres. Structural characterizations reveal that a well-defined HPC with a large surface area of 1141 m(2) g(-1) is formed when PR/SiO2 is 1:1. With further increasing PR infiltration content, macropores of carbons disappear while solid structures appear. A possible formation mechanism for the morphological transformation of HPCs is proposed. The effect of phenolic resin infiltration content on the electrochemical properties of HPCs-based materials as supercapacitor electrodes is further evaluated. The HPCs-1(PR/SiO2 = 1) electrode exhibits the highest specific capacitance of 256 F g(-1) due to its faster diffusion of electrolyte ions and lower charge transfer resistance. The relationship between the morphology and the electrochemical behavior of HPCs is also elucidated.21236003, NSFC, National Natural Science Foundation of China; 21322607, NSFC, National Natural Science Foundation of China; 21371057, NSFC, National Natural Science Foundation of Chin