Direct imaging of a zero-field target skyrmion and its polarity switch in a chiral magnetic nanodisk

A target skyrmion is a flux-closed spin texture that has two-fold degeneracy and is promising as a binary state in next generation universal memories. Although its formation in nanopatterned chiral magnets has been predicted, its observation has remained challenging. Here, we use off-axis electron holography to record images of target skyrmions in a 160-nm-diameter nanodisk of the chiral magnet FeGe. We compare experimental measurements with numerical simulations, demonstrate switching between two stable degenerate target skyrmion ground states that have opposite polarities and rotation senses and discuss the observed switching mechanism.Comment: 18 pages, 4 figure

Mn-doped CoSe2 nanosheets as high-efficiency catalysts for the oxygen evolution reaction.

In this work, we introduce for the first time an aqueous solution method followed by a selenization step to prepare Mn-doped CoSe2 nanosheets supported on nickel foam for the oxygen evolution reaction. These findings provide us highly efficient electrocatalysts instead of noble metal catalysts for the oxygen evolution reaction

Polymorphisms in thymidylate synthase gene and susceptibility to breast cancer in a Chinese population: a case-control analysis

BACKGROUND: Accumulative evidence suggests that low folate intake is associated with increased risk of breast cancer. Polymorphisms in genes involved in folate metabolism may influence DNA methylation, nucleotide synthesis, and thus individual susceptibility to cancer. Thymidylate synthase (TYMS) is a key enzyme that participates in folate metabolism and catalyzes the conversion of dUMP to dTMP in the process of DNA synthesis. Two potentially functional polymorphisms [a 28-bp tandem repeat in the TYMS 5'-untranslated enhanced region (TSER) and a 6-bp deletion/insertion in the TYMS 3'-untranslated region (TS 3'-UTR)] were suggested to be correlated with alteration of thymidylate synthase expression and associated with cancer risk. METHODS: To test the hypothesis that polymorphisms of the TYMS gene are associated with risk of breast cancer, we genotyped these two polymorphisms in a case-control study of 432 incident cases with invasive breast cancer and 473 cancer-free controls in a Chinese population. RESULTS: We found that the distribution of TS3'-UTR (1494del6) genotype frequencies were significantly different between the cases and controls (P = 0.026). Compared with the TS3'-UTR del6/del6 wild-type genotype, a significantly reduced risk was associated with the ins6/ins6 homozygous variant genotype (adjusted OR = 0.58, 95% CI = 0.35–0.97) but not the del6/ins6 genotype (OR = 1.09, 95% CI = 0.82–1.46). Furthermore, breast cancer risks associated with the TS3'-UTR del6/del6 genotype were more evident in older women, postmenopausal subjects, individuals with a younger age at first-live birth and individuals with an older age at menarche. However, there was no evidence for an association between the TSER polymorphism and breast cancer risks. CONCLUSION: These findings suggest that the TS3'-UTR del6 polymorphism may play a role in the etiology of breast cancer. Further larger population-based studies as well as functional evaluation of the variants are warranted to confirm our findings

a highly concurrent process virtual machine based on event-driven process execution model

Existing orchestration and choreography process engines only serve for dedicate process languages and majority of them show rough performance under even moderate workloads which cause them incapable for practical use. To solve the problems, the Event-driven Process Execution Model (EPEM) is presented as the common process model and the formalization of EPEM is presented to guarantee the correctness and efficiency for process transformation. A Process Virtual Machine - Once PVM is implemented based on EPEM and extended to support execution of WS-BPEL. For evaluation, the performance of Once PVM is compared with existing orchestration engines including Active BPEL, Apache ODE and Oracle BPEL Process Manager. The experimental results indicate that Once PVM shows better scalability than other tested platforms especially under high workloads. © 2012 IEEE.IEEE Comput. Soc. Tech. Comm. Electron. Commer. (TCEC)Existing orchestration and choreography process engines only serve for dedicate process languages and majority of them show rough performance under even moderate workloads which cause them incapable for practical use. To solve the problems, the Event-driven Process Execution Model (EPEM) is presented as the common process model and the formalization of EPEM is presented to guarantee the correctness and efficiency for process transformation. A Process Virtual Machine - Once PVM is implemented based on EPEM and extended to support execution of WS-BPEL. For evaluation, the performance of Once PVM is compared with existing orchestration engines including Active BPEL, Apache ODE and Oracle BPEL Process Manager. The experimental results indicate that Once PVM shows better scalability than other tested platforms especially under high workloads. © 2012 IEEE

An Apple Fungal Infection Detection Model Based on BPNN Optimized by Sparrow Search Algorithm

To rapidly detect whether apples are infected by fungi, a portable electronic nose was used in this study to collect the gas information from apples, and the collected information was processed by smoothing filtering, data dimensionality reduction, and outlier removal. Following this, we utilized K-nearest neighbors (KNN), random forest (RF), support vector machine (SVM), a convolutional neural network (CNN), a back-propagation neural network (BPNN), a particle swarm optimization–back-propagation neural network (PSO-BPNN), a gray wolf optimization–backward propagation neural network (GWO-BPNN), and a sparrow search algorithm–backward propagation neural network (SSA-BPNN) model to discriminate apple samples, and adopted the 10-fold cross-validation method to evaluate the performance of each model. The results show that SSA can effectively optimize the performance of the BPNN, such that the recognition accuracy of the optimized SSA-BPNN model reaches 98.40%. This study provides an important reference value for the application of an electronic nose in the non-destructive and rapid detection of fungal infection in apples

The role of Zn interstitials in cobalt-doped ZnO diluted magnetic semiconductors

Co-doped ZnO samples Zn1-xCoxO and CoyZn1-yO were prepared by the sol-gel and magnetron sputtering methods, respectively. Although the Co K-edge extended x-ray absorption fine structure spectra show that the doped Co ions are located at the Zn substitutional sites for both Zn1-xCoxO (x <= 0.05) and CoyZn1-yO (y <= 0.05) samples, magnetic measurements show paramagnetism in Zn1-xCoxO (x <= 0.05) and high temperature ferromagnetism in CoyZn1-yO (y <= 0.05). An experimental and numerical study of the O K-edge x-ray absorption near-edge structure spectra reveals that the incorporation of the Zn interstitials in the lattice is crucial to the appearance of high temperature ferromagnetism in CoyZn1-yO (y <= 0.05) samples. (C) 2010 American Institute of Physics. [doi:10.1063/1.3437082