Advanced graphene recording device for spin-orbit torque magnetoresistive random access memory.

The non-volatile spin-orbit torque magnetic random access memory (SOT-MRAM) is a very attractive memory technology for near future computers because it has various advantages such as non-volatility, high density and scalability. In the present work we propose a model of a graphene recording device for the SOT-MRAM unit cell, consisting of a quasi-freestanding graphene intercalated with Au and an ultra-thin Pt layer sandwiched between graphene and a magnetic tunnel junction. As a result of using the claimed graphene recording memory element, a faster operation and lower energy consumption will be achieved under the recording information by reducing the electric current required to record. The efficiency of the graphene recording element was confirmed by the experimental results and the theoretical estimations.

Effects of Covalent Conjugates of Fullerene Derivatives with Xanthene Dyes on Activity of Ca2+-ATPase of the Sarcoplasmic Reticulum.

The effects of the newly synthesized covalent conjugates of water-soluble fullerene derivatives (WSFD) with xanthene dyes: polyanionic WSFD-fluorescein (1), polycationic WSFD-fluorescein (2), polyanionic WSFD-eosin (3), and polyanionic WSFD (4), polycationic WSFD (5), fluorescein (6) and eosin (7), on activity of the membrane-bound Ca2+-ATPase of the sarcoplasmic reticulum (SR Ca2+-ATPase) were studied. Compounds 1, 3, 4, 6, and 7 inhibit the hydrolytic function of the enzyme, the inhibition constants for these compounds are Ki=1.3×10-5 M (1), Ki=4.7×10-6 M (3), Ki=2.5×10-6 M (4), Ki=6.1×10-5 M (6), and Ki=5.8×10-6 M (7). The effects of compounds 3, 6, and 7 on the hydrolytic function of the enzyme is competitive; compounds 1 and 4 are noncompetitive. Polycationic WSFD fluorescein (2) and polycationic WSFD (5) do not affect ATP hydrolysis, but inhibit active Ca2+ transport in a concentration of 0.01 mM by 100±10 and 40±4%, respectively. Conjugates 1 and 3 completely inhibit the hydrolytic and transport functions of the enzyme in a concentration of 0.01 mM, and in a concentration of 0.001 mM inhibit active Ca2+ transport by 60±6 and 55±6% uncoupling the hydrolytic and transport functions of SR Ca2+-ATPases. The obtained results demonstrate a significant effect of the studied compounds on the active transmembrane transfer of Ca2+ and make it possible to predict the presence of antimetastatic and antiaggregatory activities of the studied compounds.

The graphene/Au/Ni interface and its application in the construction of a graphene spin filter.

A modification of the contact of graphene with ferromagnetic electrodes in a model of the graphene spin filter allowing restoration of the graphene electronic structure is proposed. It is suggested for this aim to intercalate into the interface between the graphene and the ferromagnetic (Ni or Co) electrode a Au monolayer to block the strong interaction between the graphene and Ni (Co) and, thus, prevent destruction of the graphene electronic structure which evolves in direct contact of graphene with Ni (Co). It is also suggested to insert an additional buffer graphene monolayer with the size limited by that of the electrode between the main graphene sheet providing spin current transport and the Au/Ni electrode injecting the spin current. This will prevent the spin transport properties of graphene from influencing contact phenomena and eliminate pinning of the graphene electronic structure relative to the Fermi level of the metal, thus ensuring efficient outflow of injected electrons into the graphene. The role of the spin structure of the graphene/Au/Ni interface with enhanced spin-orbit splitting of graphene π states is also discussed, and its use is proposed for additional spin selection in the process of the electron excitation.

Nanoparticles of water-soluble dyads based on amino acid fullerene C60 derivatives and pyropheophorbide: Synthesis, photophysical properties, and photodynamic activity.

Synthesis, spectral properties, and photodynamic activity of water-soluble amino acid fullerene C60 derivatives (AFD) and four original AFD-PPa dyads, obtained by covalent addition of dye pyropheophorbide (PPa) to AFD, were studied. In aqueous solution, these AFD-PPa dyads form nanoassociates as a result of self-assembly. In this case, a significant change in the absorption spectra and strong quenching of the dye fluorescence in the structure of the dyads were observed. A comparison of superoxide or singlet oxygen generation efficiency of the studied compounds in an aqueous solution showed the photodynamic mechanism switching from type II (singlet oxygen generation of the native dye) to I type (superoxide generation of dyads). All dyads have pronounced phototoxicity on cells Hela with IC50 9.2 µM, 9.2 µM, 12.2 µM for dyads Val-C60-PPa, Ala-C60-PPa and Pro-C60-PPa, respectively. Such facilitation of type I photodynamic mechanism could be perspective against hypoxic tumors.

Non-monotonic variation of the Kramers point band gap with increasing magnetic doping in BiTeI.

Polar Rashba-type semiconductor BiTeI doped with magnetic elements constitutes one of the most promising platforms for the future development of spintronics and quantum computing thanks to the combination of strong spin-orbit coupling and internal ferromagnetic ordering. The latter originates from magnetic impurities and is able to open an energy gap at the Kramers point (KP gap) of the Rashba bands. In the current work using angle-resolved photoemission spectroscopy (ARPES) we show that the KP gap depends non-monotonically on the doping level in case of V-doped BiTeI. We observe that the gap increases with V concentration until it reaches 3% and then starts to mitigate. Moreover, we find that the saturation magnetisation of samples under applied magnetic field studied by superconducting quantum interference device (SQUID) magnetometer has a similar behaviour with the doping level. Theoretical analysis shows that the non-monotonic behavior can be explained by the increase of antiferromagnetic coupled atoms of magnetic impurity above a certain doping level. This leads to the reduction of the total magnetic moment in the domains and thus to the mitigation of the KP gap as observed in the experiment. These findings provide further insight in the creation of internal magnetic ordering and consequent KP gap opening in magnetically-doped Rashba-type semiconductors.

Dirac cone intensity asymmetry and surface magnetic field in V-doped and pristine topological insulators generated by synchrotron and laser radiation.

Effect of magnetization generated by synchrotron or laser radiation in magnetically-doped and pristine topological insulators (TIs) is presented and analyzed using angle-resolved photoemission spectroscopy. It was found that non-equal photoexcitation of the Dirac cone (DC) states with opposite momenta and spin orientation indicated by the asymmetry in photoemission intensity of the DC states is accompanied by the k||-shift of the DC states relative to the non-spin-polarized conduction band states located at k|| = 0. We relate the observed k||-shift to the induced surface in-plane magnetic field and corresponding magnetization due to the spin accumulation. The direction of the DC k||-shift and its value are changed with photon energy in correlation with variation of the sign and magnitude of the DC states intensity asymmetry. The theoretical estimations describe well the effect and predict the DC k||-shift values which corroborate the experimental observations. This finding opens new perspectives for effective local magnetization manipulation.

Spin-resolved band structure of heterojunction Bi-bilayer/3D topological insulator in the quantum dimension regime in annealed Bi2Te2.4Se0.6.

Two- and three-dimensional topological insulators are the key materials for the future nanoelectronic and spintronic devices and quantum computers. By means of angle- and spin-resolved photoemission spectroscopy we study the electronic and spin structure of the Bi-bilayer/3D topological insulator in quantum tunneling regime formed under the short annealing of Bi2Te2.4Se0.6. Owing to the temperature-induced restructuring of the topological insulator's surface quintuple layers, the hole-like spin-split Bi-bilayer bands and the parabolic electronic-like state are observed instead of the Dirac cone. Scanning Tunneling Microscopy and X-ray Photoemission Spectroscopy measurements reveal the appearance of the Bi2 terraces at the surface under the annealing. The experimental results are supported by density functional theory calculations, predicting the spin-polarized Bi-bilayer bands interacting with the quintuple-layers-derived states. Such an easily formed heterostructure promises exciting applications in spin transport devices and low-energy electronics.

[The role of cefepime, a 4th-generation cephalosporin, in treating patients with surgical sepsis]. / Rol' tsefalosporina IV pokoleniia tsefepima v lechenii bol'nykh s khirurgicheskim sepsisom.

Cefepime (Maxipime) was used in the management of 22 patients at the age of 18 to 73 years with the surgical sepsis syndrome (SAPS > 15). In 16 patients surgical sepsis was due to pancreatitis, appendititis, abdominal wound or trauma or complications after planned surgical interventions on the organs of the abdominal cavity. In the other 6 patients surgical sepsis was due to inflammatory processes in soft tissues after minor trauma. In 10 patients (group 1) cefepime was used after the pathogen verification and antibioticogram examination. In 12 patients (group 2) the antibiotic was used in the empirical therapy as the first line drug after the patients acceptance from another unit when the pathogen nature was obscure. Cefepime was administered intravenously in a dose of 2.0 g twice daily for 7 to 10 days in combination with metronidazole in a dose of 0.5 g thrice daily. After 5-6 days of the treatment the patients of group 1 were switched to the cefepime intramuscular regimen. The lethality totaled 18 per cent (4 patients). Three of them were from group 2. The patients died of progressive polyorgan insufficiency. It is characteristic that in no cases cefepime induced septic shock due to the endotoxin escape. No septicopyemia was as well observed even in the patients with verified bacteremia due to Staphylococcus aureus.

[Use of antegrade endolymphatic administration of antistaphylococcal and antipseudomonal plasma in the treatment of infectious complications in severe multiple trauma]. / Primenenie antegradnogo éndolimfaticheskogo vvedeniia antistafilokokkovoi i antisinegnoinoi plazmy v lechenii infektsionnykh oslozhnenii pri tiazheloi sochetannoi travme.

The article deals with the treatment of infectious complications in persons with severe concurrent trauma. Microbiological study of the wound discharge and damaged tissues showed staphylococci and blue pus bacillus to be the principal causative agents of infectious complications. In view of the poor response of the immune system to the opportunistic flora, the performance of passive immunization with antistaphylococcal and antipseudomonal plasma is pathogenetically grounded. Taking into account the involvement of the lymphatic system in the infectious process, endolymphatic administration of the immune plasma is suggested.

[Effectiveness of using gelatin sponge for hemostasis during treatment of acute iliofemoral venous thrombosis]. / Effektivnost' ispol'zovaniia zhelatinovoi gubki dlia gemostaza pri lechenii bol'nykh s ostrym podvzdoshno-bedrennym venoznym yrombozom.

Patients with acute thrombosis of profound large veins of the lower limbs and pelvis (83) were administered anticoagulants of indirect action, heparin and thrombolytic drugs (fibrinolysin or thrombolytin), as a result of it all patients showed marked hypocoagulemia, contributing to increased blood loss during the operation and the development of hemorrhagic complications postoperatively. With the purpose of hemostasis gelatin sponge was employed in 47 operative interventions. The number of hemorrhagic complications, while using the sponge, was reliably decreased as compared with the group of patients (57) in whom the sponge was not employed.

[Wound infection]. / Ranevaia infektsiia.

A present-day view on the problem of wound infection is analyzed with special reference to recent data. Active surgical approach in combination with many-component antibacterial and correcting treatment still remains important in prevention and treatment of wound infection.

[Effectiveness of oxygen-vitamin cocktails in preventing anemia, rickets, post-vaccinal complications and the risk of perinatal pathology in infants]. / Effektivnost' kislorodno-vitaminnykh kokteilei v profilaktike anemii, rakhita, postvaktsinal'nykh oslozhnenii, realizatsii riska perinatal'noi patologii u detei rannego vozrasta.

Data are presented on the composition of oxygen-vitamin cocktales used for simultaneous prevention and treatment of rickets, anemia, dystrophy, postvaccinal side effects and realization of perinatal pathology risk into a disease after birth. Mechanisms of the action of varying components of the cocktails, methods and duration of the prophylactic course, effectiveness of their use in the catamnesis have been described.

Giant Rashba splitting in graphene due to hybridization with gold.

Graphene in spintronics is predominantly considered for spin current leads of high performance due to weak intrinsic spin-orbit coupling of the graphene π electrons. Externally induced large spin-orbit coupling opens the possibility of using graphene in active elements of spintronic devices such as the Das-Datta spin field-effect transistor. Here we show that Au intercalation at the graphene-Ni interface creates a giant spin-orbit splitting (~100 meV) of the graphene Dirac cone up to the Fermi energy. Photoelectron spectroscopy reveals the hybridization with Au 5d states as the source for this giant splitting. An ab initio model of the system shows a Rashba-split spectrum around the Dirac point of graphene. A sharp graphene-Au interface at the equilibrium distance accounts for only ~10 meV spin-orbit splitting and enhancement is due to the Au atoms in the hollow position that get closer to graphene and do not break the sublattice symmetry.

Is there a rashba effect in graphene on 3d ferromagnets?

Graphene is considered a candidate material for spintronics. Recently, graphene grown on Ni(111) has been reported to show a Rashba effect which depends on the magnetization. By spin- and angle-resolved photoelectron spectroscopy, we investigate the preconditions for such an effect for graphene on Ni as well as on Co which has a approximately 3x larger 3d magnetic moment: (i) spin polarization or (ii) exchange splitting of graphene pi states in normal emission geometry, and (iii) Rashba-type spin-orbit splitting off normal. As none of these are found to be of considerable size, the reported effect is neither Rashba-type, nor due to the spin-orbit coupling, nor involving the electron spin.

Electronic and magnetic properties of quasifreestanding graphene on Ni.

For the purpose of recovering the intriguing electronic properties of freestanding graphene at a solid surface, graphene self-organized on a Au monolayer on Ni(111) is prepared and characterized by scanning tunneling microscopy. Angle-resolved photoemission reveals a gapless linear pi-band dispersion near K[over] as a fingerprint of strictly monolayer graphene and a Dirac crossing energy equal to the Fermi energy (EF) within 25 meV meaning charge neutrality. Spin resolution shows a Rashba effect on the pi states with a large (approximately 13 meV) spin-orbit splitting up to EF which is independent of k.

[Survival of bacteria and the fate of Escherichia coli DNA in amino acid deficiency]. / Gibel' bakterii i sud'ba DNK Escherichia coli pri aminokislotnom golodanii.

The survival rate of an E. coli polyauxotrophous strain AB1157 and the behaviour of its DNA were studied when the strain was incubated for a long time at 43 degrees C in a medium deficient in glucose, phosphates and amino acids. Under these conditions, the survival rate fell down to 10%, but no cell lysis occurred. DNA synthesis stopped within the first two hours of starvation. Neither DNA degradation, despiralization nor decrease of its molecular weight could be detected during the entire starvation. Therefore, the death of E. coli cells under these conditions was not associated with DNA damages.