Magnonic beam splitter: The building block of parallel magnonic circuitry

We demonstrate a magnonic beam splitter that works by inter-converting magnetostatic surface and backward-volume spin waves propagating in orthogonal sections of a T-shaped yttrium iron garnet structure. The inter-conversion is enabled by the overlap of the surface and volume spin wave bands. This overlap results from the demagnetising field induced along the transversely magnetised section(-s) of the structure and the quantization of the transverse wave number of the propagating spin waves (which are therefore better described as waveguide modes). In agreement with numerical micromagnetic simulations, our Brillouin light scattering imaging experiments reveal that, depending on the frequency, the incident fundamental waveguide magnonic modes may also be converted into higher order waveguide modes. The magnonic beam splitter demonstrated here is an important step towards the development of parallel logic circuitry of magnonics.The research leading to these results has received funding from the Russian Foundation for Basic Research (Project No. 14-07-00273), the Grant from Russian Science Foundation (Project No. 14-19-00760), the Scholarship of the President of Russian Federation (SP-313.2015.5), and from the Engineering and Physical Sciences Research Council of the United Kingdom (Project Nos. EP/L019876/1 and EP/P505526/1)

Spin wave propagation in a uniformly biased curved magnonic waveguide

This is the final version of the article. Available from American Physical Society via the DOI in this record.Using Brillouin light scattering microscopy and micromagnetic simulations, we study the propagation and transformation of magnetostatic spin waves across uniformly biased curved magnonic waveguides. Our results demonstrate that the spin wave transmission through the bend can be enhanced or weakened by modifying the distribution of the inhomogeneous internal magnetic field spanning the structure. Our results open up the possibility of optimally molding the flow of spin waves across networks of magnonic waveguides, thereby representing a step forward in the design and construction of the more complex magnonic circuitry.Structure fabrication and microwave measurements were supported by a grant from the Russian Science Foundation (Grant No. 16-19-10283). This work was also partially supported by the Russian Foundation for Basic Research (Grant No. 16-37-00217), the Scholarship and Grant of the President of RF (Grant No. SP-313.2015.5, MK-5837.2016.9), and the Engineering and Physical Sciences Research Council of the United Kingdom (Projects No. EP/L019876/1 and No. EP/P505526/1)

Winter air temperature during the Holocene optimum in the north-eastern part of the east European plain based on ice wedge stable isotope records

Early Holocene winter air temperatures have been reconstructed for the northeastern part of the East European Plain using stable isotope (δ18O and δ2H) records of syngenetic ice wedges. We show that ice wedges here actively grew synchronously with accumulation of peatlands in bogged and forested depressions between 10 and 8 cal ka BP, corresponding to the early Holocene Thermal Maximum. The slope of the δ2H-δ18O regression line is close to the global meteoric water line. This suggests the preservation of winter precipitation signal in the ice wedge with minor isotope transformation. The low range of stable isotope values in the ice wedge indicates quite stable winter climate conditions, favorable to ice wedge growth. Reconstructed mean winter air temperature was close to modern, but it is assumed that air temperature of the coldest winter month was lower and more stable than at present

Distribution and Regulation of L-Type Ca2+ Channels in Cardiomyocyte Microdomains

Cardiac excitation involves action potential generation by individual cells and its conduction from cell to cell through intercellular gap junctions. Excitation of the cellular membrane results in opening of the voltage-gated L-type Ca2+ channels, which allow a small amount of Ca2+ to enter the cell. This triggers the release of a much greater amount of Ca2+ from the intracellular Ca2+ store, the sarcoplasmic reticulum, and gives rise to the systolic Ca2+ transient and contraction. These processes are highly regulated by the autonomic nervous system, which ensures the acute and reliable contractile function of the heart and the short-term modulation of this function upon changes in heart rate or workload. Recently, it became evident that discrete clusters of L-type Ca2+ channels exist in the sarcolemma, where they form an interacting network with regulatory proteins and receptors. It allows the specificity, reliability, and accuracy of autonomic modulation of the excitation-contraction processes by a variety of neurohormonal pathways. Disruption in subcellular targeting of calcium channels and associated signaling pathways may contribute to the pathophysiology of a variety of cardiac diseases including heart failure and certain arrhythmias. This chapter reviews the emerging understanding of microdomain-specific distribution, functioning, regulation, and remodeling of L-type Ca2+ channels in atrial and ventricular myocytes and their contributions to the cellular signaling and cardiac pathology