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We experimentally study magnetization reversal curves for MnTe single crystals, which is the altermagnetic candidate. Above 85 K temperature, we confirm the antiferromagnetic behavior of magnetization M, which is known for α-MnTe. Below 85 K, we observe anomalous low-field magnetization behavior, which is accompanied by the sophisticated angle dependence with beating pattern as the interplay between maxima and minima: in low fields, shows ferromagnetic-like 180° periodicity, while at high magnetic fields, the periodicity is changed to the 90° one. This angle dependence is the most striking result of our experiment, while it can not be expected for standard magnetic systems. In contrast, in altermagnets, symmetry allows ferromagnetic behavior only due to the spin–orbit coupling. Thus, we claim that our experiment shows the effect of weak spin–orbit coupling in MnTe, with crossover from relativistic to non-relativistic net magnetization, and, therefore, we experimentally confirm altermagnetism in MnTe. [ABSTRACT FROM AUTHOR]

We experimentally investigate magnetization reversal curves for a GeTe topological semimetal. In addition to the known lattice diamagnetic response, we observe narrow magnetization loop in low fields, which should not be expected for non-magnetic material. The diamagnetic hysteresis loop is unusual, so the saturation level is negative in positive fields, and the loop is passed clockwise, in contrast to standard ferromagnetic behavior. We show, that the experimental hysteresis curves cannot be obtained from standard ferromagnetic ones by adding/subtracting of any linear dependence, or even by considering several interacting magnetic phases. The latter possibility is also eliminated by the remanence plots technique (Henkel or plots). We explain our results as a direct consequence of the correlation between ferroelectricity and spin-polarized surface states in GeTe, similarly to magnetoelectric structures. [ABSTRACT FROM AUTHOR]

The investigation on domain structure evolution under variation of magnetostriction, phase composition and internal stresses was provided. Glass-coated amorphous microwires of Fe73.5Cu1Nb3Si13.5B9 composition with positive magnetostriction were studied. The decrease of internal stresses and controlled crystallization leading to changes in the phase composition and reduction of magnetostriction were observed under different thermal treatment. The domain structure of the as-prepared and annealed microwires was studied by the method of magneto-optical indicator films. The estimation of the domain size was realized by Fourier transform from the domain contrast of magneto-optical images. The regularities of the influence of thermal treatment on the magnetic domain structure of microwires have been estimated. [ABSTRACT FROM AUTHOR]

The quantitative monitoring of kinetic parameters for the interaction of biomolecules is demanded in many fields of fundamental and applied research. In this study, some compact biosensor devices, which are characterized by high energy efficiency and provide ultrasensitive real-time registration of changes in the thickness of biomolecular complexes on widely available disposable sensor chips, have been developed on the basis of low-coherence interferometry. These instruments are electrically and optically safe, can be powered and controlled by a laptop USB port, and have passive drift-suppressing thermal insulation. The potentialities of these instruments are demonstrated on the kinetic characterization of antibodies as an example to select the most efficient ones as immunoassays for the brain natriuretic peptide, which is a marker of cardiovascular diseases. The devices and methods developed provide for efficient selection of optimal biorecognizing agents for in vitro diagnosis, targeted nanopreparation delivery, etc. [ABSTRACT FROM AUTHOR]

We investigate electron transport along the surface of WTe2 three-dimensional single crystals, which are characterized by the coexistence of the conductivity and ferroelectricity of a Weyl semimetal at room temperature. We find that a nonlinear behavior of the differential resistance of WTe2 is accompanied by a slow relaxation process, which appears as the dependence on the sign of the current change. This observation is confirmed by direct investigation of time-dependent relaxation curves. While strongly nonlinear differential resistance should be expected for zero-gap WTe2, the slow relaxation in transport is very unusual for well-conducting semimetals at room temperature. We establish that a nonmonotonic dependence of the amplitude of the effect on the driving current well corresponds to the known Sawyer–Tower's ferroelectric hysteresis loop. The possibility to induce polarization current by source-drain field variation is unique for WTe2, since it is a direct consequence of the coexistence of ferroelectricity and metallic conduction. This conclusion is also confirmed by gate voltage dependencies, so our results can be understood as a direct demonstration of the ferroelectric behavior of WTe2 in charge transport experiment. [ABSTRACT FROM AUTHOR]

We study conductivity of strongly disordered amorphous antimony films under high bias voltages. We observe non-linear current-voltage characteristic, where the conductivity value at zero bias is one of two distinct values, being determined by the sign of previously applied voltage. Relaxation curves demonstrate high stability of these conductivity values on a large timescale. Investigations of the antimony film structure allows to determine the percolation character of electron transport in strongly disordered films. We connect the memory effect in conductivity with modification of the percolation pattern due to recharging of some film regions at high bias voltages. [ABSTRACT FROM AUTHOR]

Magnetic microwires are unique materials with a wide range of magnetic and high-frequency properties that are of considerable interest from the point of view of the application for magnetic sensors based on microwires. The magnetic properties of microwires directly depend on the level and distribution of stresses. Therefore, the study of the magnetic properties of microwires, depending on their stressed state, is of considerable interest. This paper describes a method for measuring the hysteresis properties of amorphous microwires under stretching in situ. An experimental facility has been developed. It allows measuring the dependences of the coercivity of microwires under stretching in situ with an error of no more than 8 A/m with an external magnetizing field of 2000 A/m and a frequency of 2.5 kHz. [ABSTRACT FROM AUTHOR]

The t(8;21)(q22;q22) rearrangement represents the most common chromosomal translocation in acute myeloid leukemia (AML). It results in a transcript encoding for the fusion protein AML1-ETO (AE) with transcription factor activity. AE is considered to be an attractive target for treating t(8;21) leukemia. However, AE expression alone is insufficient to cause transformation, and thus the potential of such therapy remains unclear. Several genes are deregulated in AML cells, including KIT that encodes a tyrosine kinase receptor. Here, we show that AML cells transduced with short hairpin RNA vector targeting AE mRNAs have a dramatic decrease in growth rate that is caused by induction of apoptosis and deregulation of the cell cycle. A reduction in KIT mRNA levels was also observed in AE-silenced cells, but silencing KIT expression reduced cell growth but did not induce apoptosis. Transcription profiling of cells that escape cell death revealed activation of a number of signaling pathways involved in cell survival and proliferation. In particular, we find that the extracellular signal-regulated kinase 2 (ERK2; also known as mitogen-activated protein kinase 1 (MAPK1)) protein could mediate activation of 23 out of 29 (79%) of these upregulated pathways and thus may be regarded as the key player in establishing the t(8;21)-positive leukemic cells resistant to AE suppression. [ABSTRACT FROM AUTHOR]

The t(8;21)(q22;q22) rearrangement represents the most common chromosomal translocation in acute myeloid leukemia (AML). It results in a transcript encoding for the fusion protein AML1-ETO (AE) with transcription factor activity. AE is considered to be an attractive target for treating t(8;21) leukemia. However, AE expression alone is insufficient to cause transformation, and thus the potential of such therapy remains unclear. Several genes are deregulated in AML cells, including KIT that encodes a tyrosine kinase receptor. Here, we show that AML cells transduced with short hairpin RNA vector targeting AE mRNAs have a dramatic decrease in growth rate that is caused by induction of apoptosis and deregulation of the cell cycle. A reduction in KIT mRNA levels was also observed in AE-silenced cells, but silencing KIT expression reduced cell growth but did not induce apoptosis. Transcription profiling of cells that escape cell death revealed activation of a number of signaling pathways involved in cell survival and proliferation. In particular, we find that the extracellular signal-regulated kinase 2 (ERK2; also known as mitogen-activated protein kinase 1 (MAPK1)) protein could mediate activation of 23 out of 29 (79%) of these upregulated pathways and thus may be regarded as the key player in establishing the t(8;21)-positive leukemic cells resistant to AE suppression. [ABSTRACT FROM AUTHOR]

The structure of the [001]-oriented single crystalline tungsten probes sharpened in ultra-high vacuum using electron beam heating and ion sputtering has been studied using scanning and transmission electron microscopy. The electron microscopy data prove reproducible fabrication of the single-apex tips with nanoscale pyramids grained by the {011} planes at the apexes. These sharp, [001]-oriented tungsten tips have been successfully utilized in high resolution scanning tunneling microscopy imaging of HOPG(0001), SiC(001) and graphene/SiC(001) surfaces. The electron microscopy characterization performed before and after the high resolution STM experiments provides direct correlation between the tip structure and picoscale spatial resolution achieved in the experiments. [ABSTRACT FROM AUTHOR]

In the present study, we have applied the siRNA approach to reduce the expression of AML1-ETO and RUNX1(K83N) oncogenes, which are frequently found in leukemic cells. We have designed small hairpin RNAs (shRNA) for targeting AML1-ETO oncogene and a region close to the 5′-untranslated region of mRNA for the mutant RUNX1(K83N) oncogene and expressed the shRNAs in lentiviral vectors. We report a stable reduction in expression of oncogenes following the introduction of shRNAs into cells. [ABSTRACT FROM AUTHOR]

Magnetic structure of amorphous Fe73,9B13,2Si10,9C2 microwires was studied. The magnetic structure of the as-prepared microwire was found to consist of a magnetic core and a ring-shaped surface magnetic layer made up by radially magnetized small ring domains. The geometric characteristics of microwire magnetic structure were first experimentally determined. The width of the surface ring domains is about 5 μm, and the thickness of the surface magnetic layer is 2 μm. The magnetic core of the as-prepared microwire has been shown to consist of extensive domains, no less than 500 μm in size, and their spontaneous magnetization vector deviating from the microwire axis. The effect of magnetostriction on magnetic structure and its changes induced by magnetization has been established. The magnetic structure model for microwires with positive magnetostriction constant is proposed. [ABSTRACT FROM AUTHOR]