Much theoretical and experimental attention has been focused on the electrical switching of the antiferromagnetic (AFM) Néel vector via spin-orbit torque. Measurements employing multiterminal ...patterned structures of Pt/AFM show recurring signals of the supposedly planar Hall effect and magnetoresistance, implying AFM switching. We show in this Letter that similar signals have been observed in structures with and without the AFM layer, and of an even larger magnitude using different metals and substrates. These may not be the conclusive evidence of spin-orbit torque switching of AFM, but the thermal artifacts of patterned metal structure on substrate. Large current densities in the metallic devices, beyond the Ohmic regime, can generate unintended anisotropic thermal gradients and voltages. AFM switching requires unequivocal detection of the AFM Néel vector before and after SOT switching.
The inverse spin Hall effect (ISHE) has been observed only in nonmagnetic metals, such as Pt and Au, with a strong spin-orbit coupling. We report the observation of ISHE in a ferromagnetic permalloy ...(Py) on ferromagnetic insulator yttrium iron garnet (YIG). Through controlling the spin current injection by altering the Py-YIG interface, we have isolated the spin current contribution and demonstrated the ISHE in a ferromagnetic metal, the reciprocal phenomenon of the anomalous Hall effect. A large spin Hall angle in Py, determined from Py thin films of different thicknesses, indicates many other ferromagnetic metals may be exploited as superior pure spin current detectors and for applications in spin current.
The acute magnetic proximity effects in Pt/YIG compromise the suitability of Pt as a spin current detector. We show that Au/YIG, with no anomalous Hall effect and a negligible magnetoresistance, ...allows the measurements of the intrinsic spin Seebeck effect with a magnitude much smaller than that in Pt/YIG. The experiment results are consistent with the spin polarized density functional calculations for Pt with a sizable and Au with a negligible magnetic moment near the interface with YIG.
Platinum (Pt) metal, being nonmagnetic and with a strong spin-orbit coupling interaction, has been central in detecting the pure spin current and establishing most of the recent spin-based phenomena. ...Magnetotransport measurements, both electrical and thermal, conclusively show strong ferromagnetic characteristics in thin Pt films on the ferromagnetic insulator due to the magnetic proximity effects. The pure spin current phenomena measured by Pt, including the inverse spin Hall and the spin Seebeck effects, are thus contaminated and not exclusively established.
Aims
This study aims to characterize the biofilm produced by mono‐ and dual‐species of Shewanella baltica and Pseudomonas fluorescens as fish spoilers at the different incubation temperature, and to ...elucidate the interactive behaviour of dual‐species biofilm development.
Methods and Results
The mono‐ and dual‐species biofilm formation and adhesion characteristics of S. baltica and P. fluorescens were evaluated by using crystal violet staining, scanning electron microscopy and confocal laser scanning microscopy. Results showed that P. fluorescens had significantly higher biofilm biomass and polysaccharides production than S. baltica, and two isolates reached the maximum biofilm biomass during the early stationary phase. Lower biomass and polysaccharides in dual‐species biofilms were observed compared to mono‐species of P. fluorescens. Meanwhile, S. baltica and P. fluorescens formed fragile and viscous pellicles with different spatial architectures respectively. In dual‐species pellicle few large microcolonies were dominated by P. fluorescens. Compared to mono‐species of PF07, adherent cell population and biofilm thickness at the developing phase significantly decreased, and biofilm‐forming cycle prolonged in the dual‐species biofilms. Biofilm formation and adhesion of mono‐ and dual‐species at 4 or 15°C were significantly higher than at 30°C during the same phase. The culture supernatant extracts of the two spoilage strains greatly inhibited biofilm development to each other.
Conclusions
Shewanella baltica and P. fluorescens had different biofilm and pellicle characteristics, and the inhibitory development on dual‐species biofilm was associated with the competitive interaction by the two psychrotrophic spoilage bacteria.
Significance and Impact of the Study
This work contributes to a better understanding of interactive behaviour of multispecies biofilm communities by psychrotrophic spoilage bacteria at low temperature, which could contribute to further control contamination of spoilage organism during the preservation and processing of aquatic products.
This study investigated daily delta 18O variations of water vapour ( delta 18Ov) and precipitation ( delta 18Op) simultaneously at Nagqu on the central Tibetan Plateau for the first time. Data show ...that the delta 18O tendencies of water vapour coincide strongly with those of associated precipitation. The delta 18O values of precipitation affect those of water vapour not only on the same day, but also for the following several days. In comparison, the delta 18O values of local water vapour may only partly contribute to those of precipitation. During the entire sampling period, the variations of delta 18Ov and delta 18Op at Nagqu did not appear dependent on temperature, but did seem significantly dependent on the joint contributions of relative humidity, pressure, and precipitation amount. In addition, the delta 18O changes in water vapour and precipitation can be used to diagnose different moisture sources, especially the influences of the Indian monsoon and convection. Moreover, intense activities of the Indian monsoon and convection may cause the relative enrichment of delta 18Op relative to delta 18Ov at Nagqu (on the central Tibetan Plateau) to differ from that at other stations on the northern Tibetan Plateau. These results indicate that the effects of different moisture sources, including the Indian monsoon and convection currents, need be considered when attempting to interpret paleoclimatic records on the central Tibetan Plateau.
Photoemission experiments have shown that Bi2Se3 is a topological insulator. By controlled doping, we have obtained crystals of Bi2Se3 with nonmetallic conduction. At low temperatures, we uncover a ...novel type of magnetofingerprint signal which involves the spin degrees of freedom. Given the mm-sized crystals, the observed amplitude is 200-500x larger than expected from universal conductance fluctuations. The results point to very long phase-breaking lengths in an unusual conductance channel in these nonmetallic samples. We discuss the nature of the in-gap conducting states and their relation to the topological surface states.
Background and Aim
Carbapenem resistance has become a major obstacle in combating Acinetobacter baumannii infections. Although enzymatic degradation by β‐lactamases is the pivotal mechanism of ...carbapenem resistance, porin deficiency has also been implicated in the mechanism. In this study, outer membrane proteins (OMPs) pattern of a clinical multidrug‐resistant A. baumannii isolate were analysed in order to attain a deeper understanding of carbapenem‐resistance strategies.
Methods
OMPs extracts, respectively, separated from carbapenem‐resistant and ‐susceptible clinical A. baumannii isolates were compared using two‐dimensional polyacrylamide gel electrophoresis. Differentially expressed proteins were identified by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF).
Results
Twenty‐three differently expressed proteins were identified between the resistant and susceptible isolates. Among them, six were annotated convincingly as OMPs in UniProt database. CarO was found absent from the resistant isolate and the expression levels of Omp33‐36 and Omp25 were significantly lower than that in the susceptible counterpart. Strikingly, a LysM domain/BON superfamily protein, which has been linked to carbapenem resistance in Klebsiella pneumoniae, was found underexpressed by tenfold in the resistant isolate.
Conclusion
Our study verified some porins which have been proven to play an important role in bacterial resistance against carbapenems. Underexpression of the LysM domain/BON superfamily protein may indicate its possible engagement in bacterial drug resistance, but its actual role requires more investigation.
Significance and Impact of the Study: This study identified some porins including CarO, Omp33‐36 and OmpA that are differentially expressed in carbapenem‐resistant Acinetobacter baumannii by comparing outer membrane proteomes of a clinical carbapenem‐resistant isolate vs a susceptible one through 2‐DE. More strikingly, this study discovered an association between carbapenem resistance and the LysM domain/BON superfamily protein in A. baumannii.
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