Interplay between spin wave and magnetic vortex

In this paper, the interplay between spin wave and magnetic vortex is studied. We find three types of magnon scatterings: skew scattering, symmetric side deflection and back reflection, which associate with respectively magnetic topology, energy density distribution and linear momentum transfer torque within vortex. The vortex core exhibits two translational modes: the intrinsic circular mode and a coercive elliptical mode, which can be excited based on permanent and periodic magnon spin-transfer torque effects of spin wave. Lastly, we propose a vortex-based spin wave valve in which via inhomogeneity modulation we access arbitrary control of the phase shift.Comment: 33 pages, 23 figures, 1 tabl

Cerebrospinal fluid oligoclonal bands in Chinese patients with multiple sclerosis: the prevalence and its association with clinical features

BackgroundCerebrospinal fluid oligoclonal band (CSF-OCB) is an established biomarker in diagnosing multiple sclerosis (MS), however, there are no nationwide data on CSF-OCB prevalence and its diagnostic performance in Chinese MS patients, especially in the virtue of common standard operation procedure (SOP).MethodsWith a consensus SOP and the same isoelectric focusing system, we conducted a nationwide multi-center study on OCB status in consecutively, and recruited 483 MS patients and 880 non-MS patients, including neuro-inflammatory diseases (NID, n = 595) and non-inflammatory neurological diseases (NIND, n=285). Using a standardized case report form (CRF) to collect the clinical, radiological, immunological, and CSF data, we explored the association of CSF-OCB positivity with patient characters and the diagnostic performance of CSF-OCB in Chinese MS patients. Prospective source data collection, and retrospective data acquisition and statistical data analysis were used.Findings369 (76.4%) MS patients were OCB-positive, while 109 NID patients (18.3%) and 6 NIND patients (2.1%) were OCB-positive, respectively. Time from symptom onset to diagnosis was significantly shorter in OCB-positive than that in OCB-negative MS patients (13.2 vs 23.7 months, P=0.020). The prevalence of CSF-OCB in Chinese MS patients was significantly higher in high-latitude regions (41°-50°N)(P=0.016), and at high altitudes (>1000m)(P=0.025). The diagnostic performance of CSF-OCB differentiating MS from non-MS patients yielded a sensitivity of 76%, a specificity of 87%.InterpretationThe nationwide prevalence of CSF-OCB was 76.4% in Chinese MS patients, and demonstrated a good diagnostic performance in differentiating MS from other CNS diseases. The CSF-OCB prevalence showed a correlation with high latitude and altitude in Chinese MS patients

An Entropy-Based Investigation into Bivariate Drought Analysis in China

Because of the high correlation between random variables of drought duration and severity, their joint distribution is difficult to obtain by traditional mathematical methods. However, the copula method has proved to be a useful tool for analyzing the frequency of drought duration and severity. Most studies have used different marginal distribution functions to fit the drought duration and severity distributions. This requires a great deal of contrast analysis, and sometimes two or more distributions fit the data well. Based on entropy theory, however, a unified probability distribution function is derived which reduces complex contrast analysis and improves the filtering distribution function. Based on monthly precipitation data at 162 stations in China for 1961–2015, the monthly standardized precipitation index was calculated and used to extract drought duration and severity. Then the entropy distribution was used to fit the distributions of drought duration and severity, and to establish the correspondence between them. The probabilities of the interval and return periods were then determined using the copula method. An analysis of the discrepancy between the conventional and entropy-based methods indicated that the entropy distribution showed a better fit than conventional methods for drought duration distribution, although no obvious difference was found in drought severity distribution. The entropy-based results were more consistent with the empirical data, whereas conventional methods showed apparent deviation in some drought types. Hence, the entropy-based method is proposed as an alternative method of deriving the marginal distributions of drought duration and severity, and for analyzing the interval probability and return period in China

Limonin Derivatives via Hydrogenation: Structural Identification and Anti-Inflammatory Activity Evaluation

Limonin is a natural compound which is rich in the fruit of various plants of the Rutaceae family and demonstrated to have a wide range of biological activities. In this work, seven limonin derivatives were successfully synthesized by hydrogenation of limonin, using different reducing agents (sodium cyanoborohydride, lithium aluminum hydride, and sodium borohydride). The chemical structure of the seven derivatives was characterized and identified by a series of techniques, including HR-ESI-MS, 1H-NMR, 13C-NMR, 2D-NMR, and IR. Among the seven limonin derivatives, six limonin derivatives were found to be new compounds which have not been previously reported. Then, the anti-inflammatory activities of the seven synthesized limonin derivatives, as well as the anti-inflammatory activities of eight known natural limonins, were evaluated and compared. Natural limonins, 30-O-Acetylhainangranatumin E and Xylogranatin A, presented significantly better anti-inflammatory activity. Xylogranatin A could inhibit LPS-induced RAW264.7 cell inflammatory factors, with a 90.0% inhibition ratio of TNF-α and 63.77% inhibition ratio of NO release in LPS-induced BV2 cells at 10 μM. Other natural limonins showed poor anti-inflammatory activity. In comparison, all the synthetic limonin derivatives showed decent anti-inflammatory activities, with the highest inhibition ratio of TNF-α of 37.8% and inhibition ratio of NO release of 12.5% in LPS-induced BV2 cells at 10 μM

Limonin Derivatives via Hydrogenation: Structural Identification and Anti-Inflammatory Activity Evaluation

Limonin is a natural compound which is rich in the fruit of various plants of the Rutaceae family and demonstrated to have a wide range of biological activities. In this work, seven limonin derivatives were successfully synthesized by hydrogenation of limonin, using different reducing agents (sodium cyanoborohydride, lithium aluminum hydride, and sodium borohydride). The chemical structure of the seven derivatives was characterized and identified by a series of techniques, including HR-ESI-MS, 1H-NMR, 13C-NMR, 2D-NMR, and IR. Among the seven limonin derivatives, six limonin derivatives were found to be new compounds which have not been previously reported. Then, the anti-inflammatory activities of the seven synthesized limonin derivatives, as well as the anti-inflammatory activities of eight known natural limonins, were evaluated and compared. Natural limonins, 30-O-Acetylhainangranatumin E and Xylogranatin A, presented significantly better anti-inflammatory activity. Xylogranatin A could inhibit LPS-induced RAW264.7 cell inflammatory factors, with a 90.0% inhibition ratio of TNF-α and 63.77% inhibition ratio of NO release in LPS-induced BV2 cells at 10 μM. Other natural limonins showed poor anti-inflammatory activity. In comparison, all the synthetic limonin derivatives showed decent anti-inflammatory activities, with the highest inhibition ratio of TNF-α of 37.8% and inhibition ratio of NO release of 12.5% in LPS-induced BV2 cells at 10 μM

Manipulation of multiple 360o domain wall structures and its current-driven motion in a magnetic nanostripe

Dynamics of multiple transverse walls (TWs) in a magnetic nanostripe is studied by micromagnetic simulations. It shows that, when TWs are arranged in a stripe with same orientation, they will attract each other and finally annihilate. However, when adjacent TWs are arranged with opposite orientation, a metastable complex wall can be formed, e.g., two TWs lead to 360o wall. For three or more TWs, the formed complex wall includes a number of 360o substructures, which is called multiple 360o structure (M360S) here. The M360S itself may be used to store multiple logical data since each 360o substructure can act as logical ”0” or ”1”. On the other hand, the M360S may behave like single TW under an applied current, namely, the M360S can be driven steadily by current like that of single TW. A parity effect of the number of 360o substructures on the critical current for the annihilation is found. Namely, when the number is odd or even, the critical current increase or decrease with the increasing of the number, respectively. The parity effect is relevant to the out-of-plane magnetic moment of the M360S

Current driven properties and the associated magnetic domain walls manipulation in U-shaped magnetic nanowires

Based on the extended Landau–Lifshitz–Gilbert method, the properties of current driven domain wall movement in U-shaped magnetic nanowires and the effect of spin wave assistance on their properties have been investigated. The results show that changes of the curvature radius of magnetic nanowire can cause the additional pinning action and the pinning action will weaken the speed of current driven domain wall movement. For U-shaped magnetic nanowires, the changes of curvature radius can be represented by the radius R at the bend. The results show that the decline of its speed non-monotonically increases with the decrease of the bending radius of magnetic nanowires. On the other hand, the assistance of applying spin waves not only enhances the movement of magnetic domain walls but also weakens the pinning action. Further research has shown that applying the appropriate spin waves at the bend changing point can completely eliminate the influence induced by bend changing, in order to ensure uniform and stable movement of current driven magnetic domain walls in U-shaped magnetic nanowires, and achieve the current driven three-dimensional racetrack memory technology

Current-driven spring-like oscillatory motion of coupled vortex walls in a two-nanostripe system

In a two closely spaced nanostripes system, the coupled vortex wall undergoes a spring-like oscillatory motion (SOM) when current is applied to both nanostripes in opposite directions. The SOM may vanish, when the current density is larger than a critical value. The critical current density for destroying the SOM decreases as the interstripe spacing increases. However, as the perpendicular anisotropy of the system increases, the critical current density firstly decreases and then increases. Two competitive effects of the perpendicular anisotropy on the SOM are shown. Moreover, diagrams of without oscillation, spring behavior and motionless phases upon the current and the interstripe spacing (or the perpendicular anisotropy) are given

Establishment of Self-incompatibility Gene cDNA Microarray to Identify S-genotypes of Pyrus pyrifolia

Based on the cDNA sequences from hyper variable (HV) regions of identified 52 S-alleles in Oriental pear cultivars, S-RNase cDNA probes were designed, and a cDNA microarray for S-RNase detections was established. Each microarray contained 240 sites from 55 cDNA probes, including all specific cDNA sequences from the HV regions of the S-alleles. Using the cDNA of pistils of tested pear cultivars as template and Cy3 fluorescently labeling primers by PCR amplification, microarray hybridization detected the S-genotype of each pear cultivar. The genotypes inferred from the cDNA microarray hybridization signals of pear cultivars such as ‘Lijiang Huangsuanli’, ‘Xiuyu’, ‘Midu Yuli’, ‘Baimianli’, and ‘Deshengxiang’ were similar to the known genotypes of all tested cultivars. The S-RNase cDNA microarrays and the oligonucleotide gene chips were then used to conduct parallel testing of 24 P. pyrifolia cultivars with unknown S-genotypes. In conclusion, the construction of cDNA microarrays has further improved the pear S-RNase detection platform

Role of zinc vacancies in driving ferromagnetism in undoped ZnO granular films

In this paper, X-ray diffraction, X-ray energy dispersive spectrometer, photoluminescence, electron paramagnetic resonance were performed to examine the evolution of intrinsic defect states during the annealing treatment for understanding the origin of ferromagnetism in undoped ZnO granular films deposited by the magnetron sputtering method. A strong link between the ferromagnetism and the zinc vacancies was established, indicating zinc vacancies may be more effective in modulating ferromagnetism than oxygen vacancies in ZnO. This novel observation is significant not only to get further insight into the ferromagnetic origin but also to tune the magnetic properties for spintronic materials