Incommensurate Spin Density Wave in Antiferromagnetic RuO_{2} Evinced by Abnormal Spin Splitting Torque.

Since the discovery of antiferromagnetism, metallic oxide RuO_{2} has exhibited numerous intriguing spintronics properties such as the anomalous Hall effect and anisotropic spin splitting effect. However, the microscopic origin of its antiferromagnetism remains unclear. By investigating the spin splitting torque in RuO_{2}/Py, we found that metallic RuO_{2} exhibits a spatially periodic spin structure which interacts with the spin waves in Py through interfacial exchange coupling. The wavelength of such structure is evaluated within 14-20 nm depending on the temperature, which is evidence of an incommensurate spin density wave state in RuO_{2}. Our work not only provides a dynamics approach to characterize the antiferromagnetic ordering in RuO_{2}, but also offers fundamental insights into the spin current generation due to anisotropic spin splitting effect associated with spin density wave.

Joint Learning of Fuzzy k-Means and Nonnegative Spectral Clustering With Side Information.

As one of the most widely used clustering techniques, the fuzzy k -means (FKM) assigns every data point to each cluster with a certain degree of membership. However, conventional FKM approach relies on the square data fitting term, which is sensitive to the outliers with ignoring the prior information. In this paper, we develop a novel and robust fuzzy k -means clustering algorithm, namely, joint learning of fuzzy k -means and nonnegative spectral clustering with side information. The proposed method combines fuzzy k -means and nonnegative spectral clustering into a unified model, which can further exploit the prior knowledge of data pairs such that both the quality of affinity graph and the clustering performance can be improved. In addition, for the purpose of enhancing the robustness, the adaptive loss function is adopted in the objective function, since it smoothly interpolates between l1 -norm and l2 -norm. Finally, experimental results on benchmark datasets verify the effectiveness and the superiority of our clustering method.

Regulatory effects of Shewanella putrefaciens isolated from shrimp Penaeus orientalis on the virulence factors of Vibrio parahaemolyticus and evaluation of the role of quorum sensing in virulence factors regulation.

As an aquatic pathogen widely present in aquatic food, Vibrio parahaemolyticus causes outbreaks of gastroenteritis across the globe. Virulence factors of V. parahaemolyticus increases with the amount of spoilage in aquatic organisms including shrimp, but mechanisms regulating its virulence factors are not well understood. In this study, five spoilage bacteria isolated from shrimp were investigated for their regulatory effects on the virulence factors including haemolysin and biofilm of V. parahaemolyticus. Among these isolates, Shewanella putrefaciens induced haemolytic activity in V. parahaemolyticus in a time-dose-temperature-dependent manner and we found the main component responsible for this effect to be the supernatant or cell-free extract of S. putrefaciens. Total haemolytic activity, expression of the thermostable direct haemolysin gene tdh and biofilm production of V. parahaemolyticus were significantly up-regulated by S. putrefaciens, but also by deletion of quorum-sensing luxM or luxS gene of V. parahaemolyticus. However, this regulation by S. putrefaciens was significantly impaired by deletion of the luxM gene, but not by deletion of the luxS gene. Further study showed that S. putrefaciens exhibited a strong degradation ability on the signalling molecule acylated homoserine lactone (AHL) synthesised by the LuxM enzyme. This study revealed a novel virulence regulatory mechanism that S. putrefaciens can significantly increase the virulence factors of V. parahaemolyticus via interfering with the luxM- type quorum-sensing signalling pathway through its AHL-degradation ability.

Regulation of Thermostable Direct Hemolysin and Biofilm Formation of Vibrio parahaemolyticus by Quorum-Sensing Genes luxM and luxS.

Vibrio parahaemolyticus is a seafood opportunistic pathogen. There are evidences suggesting that virulence skills, including hemolytic activity and biofilm formation, are regulated by the luxM/luxS-dependent quorum-sensing system in V. parahaemolyticus, and their regulatory mechanism is not well understood. To better understand the virulence regulatory mechanism of V. parahaemolyticus, the luxM deletion (△luxM) and luxS deletion (△luxS) mutants were constructed and their impacts on growth, hemolysin activity, and biofilm were investigated. Results show that both luxM and luxS are involved in the adaptation to environmental conditions in early adaptive-log phase growth of V. parahaemolyticus. Thermostable direct hemolysin gene (tdh) was negatively regulated by luxM and positively regulated by luxS. The biofilm formation was negatively regulated by both luxS and luxM. This study provides an insight into some aspects of V. parahaemolyticus virulence regulation by luxM/luxS-dependent quorum-sensing system.