X-ray detection of ultrashort spin current pulses in synthetic antiferromagnets

ISSN:0021-8979ISSN:1089-755

Quenching of an antiferromagnet into high resistivity states using electrical or ultrashort optical pulses

Ultra-fast dynamics, insensitivity to external magnetic fields, or absence of magnetic stray fields are examples of properties that make antiferromagnets of potential use in the development of spintronic devices. Similar to their ferromagnetic counterparts, antiferromagnets can store information in the orientations of the collective magnetic order vector. However, also in analogy to ferromagnets, the readout magnetoresistivity signals in simple antiferromagnetic films have been weak and the extension of the electrical reorientation mechanism to optics has not been achieved. Here we report reversible and reproducible quenching of an antiferromagnetic CuMnAs film by either electrical or ultrashort optical pulses into nano-fragmented domain states. The resulting resistivity changes approach 20\% at room temperature, which is comparable to the giant magnetoresistance ratios in ferromagnetic multilayers. We also obtain a signal readout by optical reflectivity. The analog time-dependent switching and relaxation characteristics of our devices can mimic functionality of spiking neural network components

Activation of innate immune defense mechanisms contributes to polyomavirus BK-associated nephropathy

Polyomavirus-associated nephropathy (PVAN) is a significant complication after kidney transplantation, often leading to premature graft loss. In order to identify antiviral responses of the renal tubular epithelium, we studied activation of the viral DNA and the double-stranded RNA (dsRNA) sensors Toll-like receptor 3 (TLR3) and retinoic acid inducible gene-I (RIG-I) in allograft biopsy samples of patients with PVAN, and in human collecting duct cells in culture after stimulation by the dsRNA mimic polyriboinosinic:polyribocytidylic acid (poly(I:C)), cytokines, or infection with BK virus. Double staining using immunofluorescence for BK virus and TLR3 showed strong signals in epithelial cells of distal cortical tubules and the collecting duct. In biopsies microdissected to isolate tubulointerstitial lesions, TLR3 but not RIG-I mRNA expression was found to be increased in PVAN. Collecting duct cells in culture expressed TLR3 intracellularly, and activation of TLR3 and RIG-I by poly(I:C) enhanced expression of cytokine, chemokine, and IFN-b mRNA. This inflammatory response could be specifically blocked by siRNA to TLR3. Finally, infection of the collecting duct cells with BK virus enhanced the expression of cytokines and chemokines. This led to an efficient antiviral immune response with TLR3 and RIG-I upregulation without activation of IL-1b or components of the inflammasome pathway. Thus, PVAN activation of innate immune defense mechanisms through TLR3 is involved in the antiviral and anti-inflammatory response leading to the expression of proinflammatory cytokines and chemokines

The allergic sensitization in infants with atopic eczema from different countries

No study has compared allergic sensitization patterns in infants with atopic eczema from different countries. The aim of this study was to investigate the patterns of allergic sensitization in a cohort of infants with atopic eczema participating in a multicentre, international study