Physicotechnical Institute

Ectopic expression of defined sets of genetic factors can reprogram somatic cells to create induced pluripotent stem (iPS) cells. The capacity to direct human iPS cells to specific differentiated lineages and to their progenitor populations can be used for disease modeling, drug discovery, and eventually autologous cell replacement therapies. During mouse cardiogenesis, the major lineages of the mature heart, cardiomyocytes, smooth muscle cells, and endothelial cells arise from a common, multipotent cardiovascular progenitor expressing the transcription factors Isl1 and Nkx2.5. Here we show, using genetic fate-mapping, that Isl1(+) multipotent cardiovascular progenitors can be generated from mouse iPS cells and spontaneously differentiate in all 3 cardiovascular lineages in vivo without teratoma. Moreover, we report the identification of human iPS-derived ISL1(+) progenitors with similar developmental potential. These results support the possibility to use patient-specific iPS-generated cardiovascular progenitors as a model to elucidate the pathogenesis of congenital and acquired forms of heart diseases.-Moretti, A., Bellin, M., Jung, C. B., Thies, T.-M., Takashima, Y., Bernshausen, A., Schiemann, M., Fischer, S., Moosmang, S., Smith, A. G., Lam, J. T., Laugwitz, K.-L. Mouse and human induced pluripotent stem cells as a source for multipotent Isl1(+) cardiovascular progenitors.

An exact solution of Eilenberger's equations for a superconducting microbridge in the limit a ≪ ξ0, a ≪ l is given (a is the radius of the constriction between the superconductors, l is the mean free path and ξ0 is the coherence length). The current is independent of the ratio between l and ξ0 is expressed in terms of the contact resistance in the normal state. When T = 0, the magnitude of the critical current exceeds the critical current of the tunnel contact with the same resistance, by a factor of two.

Deep centers in n-type 4H–SiC and 6H–SiC irradiated with 8 MeV protons have been investigated by capacitance spectroscopy and electron paramagnetic resonance (EPR). Samples were fabricated by sublimation epitaxy or commercially produced by CREE Inc. Research Triangle Park, NC. It is showed that irradiation of wide-band gap semiconductors may lead to an increase in the concentration of uncompensated donors in an n-type material. The spectrum of deep centers in both SiC polytypes is independent of the technology of material growth or type of charged particles. However, the parameters and behavior of the radiation defects in 6H– and 4H–SiC are different. A conclusion about the possible nature of the irradiation induced centers is made on the basis of annealing behavior and EPR data. The obtained results show that proton irradiation can be used in SiC device fabrication technology for producing local high-resistance regions in the semiconductor.

Managers from 24 geopolitical entities provided data on work locus of control, job satisfaction, psychological strain, physical strain, and individualism/collectivism. The hypothesis that the salutary effects of perceived control on well-being are universal was supported because relations of work locus of control with well-being at work were similar in almost all the sampled areas. Furthermore, the individualism/collectivism level of each sample did not moderate the magnitude of correlations of work locus of control with measures of well-being. Findings indicate that control beliefs contribute to well-being universally, but we suggest that how control is manifested can still differ.

The environmental fate and the loss of toxicity of two important antifouling actives, zinc pyrithione (ZnPT) and copper pyrithione (CuPT), were investigated using a bioassay study and an outdoor microcosm study. The bioassay used inhibition of the growth of a marine diatom (Amphora coffeaeformis) to measure the toxicity of ZnPT and CuPT over time in sterile, natural, and sediment-supplemented seawater. In natural seawater and sediment-supplemented seawater in the dark and in sterile seawater exposed to light, growth inhibition was reduced at rates corresponding to the rapid degradation rates for ZnPT and CuPT measured in previous aquatic metabolism, die-away, and photolysis studies. Similarly, the bioassay results from sterile seawater in the dark were consistent with the slower degradation rates measured in abiotic hydrolysis studies. In addition to corroborating the rapid degradation of pyrithione upon exposure to light or sediment, the loss of toxicity indicated that the degradation products were not toxic at the concentrations produced from the dose, which was much higher than predicted environmental concentrations. To supplement environmental fate studies designed to elucidate single-pathway transformations, a microcosm study was conducted to integrate all of the degradation pathways. The study used two sediment and water systems, one of which was dosed during the day and the other at night. The pyrithione degraded rapidly in the water phase, with very little accumulation in the sediment. 2-Pyridine sulfonic acid (PSA) and carbon dioxide were the only detectable degradation products 30 d after dosing. Aquatic toxicity studies with PSA showed no observable effect at concentrations at least three orders of magnitude higher than those for either ZnPT or CuPT. As a result, the worst-case environmental concentration of PSA is expected to be far below the no observable effect concentration.

A monocyte chemotactic activity was found to be released by various types of cultured human cells after appropriate stimulation: normal diploid fibroblasts, peripheral blood mononuclear cells or monocytes isolated therefrom, and a number of tumor cell lines, including osteosarcoma (MG-63) and hepatoma (Malavu) but not melanoma (Bowes) cells. Cultures of diploid human fibroblasts and these tumor cells stimulated with interleukin (IL) 1 or double-stranded RNA [poly(rI).poly(rC)], or infected with viruses (measles or rubella viruses) were found to produce chemotactic activity for both monocytes and granulocytes. Media collected from fibroblasts treated with E. coli or IL 6 did not contain such activity. Granulocyte and monocyte chemotactic activities were serologically distinct, and could be separated by successive chromatographical procedures. While the granulocyte chemotactic activity of both fibroblasts and MG-63 cells had previously been identified as granulocyte chemotactic protein/IL 8, the monocyte chemotactic activity from MG-63 cells was identified by amino acid sequence analysis as a different protein recently described to be released by human glioma and myelomonocytic cell lines. In view of the similarity in their chromatographical behavior, monocyte chemotactic activities from fibroblasts, MG-63 cells and fresh monocytes can probably be assigned to identical molecules. Cultures of unfractionated peripheral blood cells, however, were found to release an additional monocyte chemotactic protein, identifiable by amino acid sequence analysis as platelet factor 4.

Polymer composite layers irradiated by 30-keV Ag+ ions with doses from 3.1×1015 to 7.5×1016 cm−2 and an ion current of 4 µA/cm2 are investigated. The composites were examined using Rutherford backscattering (RBS), transmission electron microscopy (TEM), and optical spectroscopy. As follows from electron microscopy and electron microdiffraction data, ion implantation is a promising tool for synthesizing silver nanoparticles in the surface region. The optical density spectra taken of these composites demonstrate that the silver nanoparticles exhibit unusually weak plasma resonance. The formation of silver nanoparticles in layers carbonized by ion implantation is considered. Based on the Mie theory, optical extinction spectra for silver particles in the polymer and carbon matrices are simulated and optical spectra for complex silver core-carbon sheath nanoparticles are calculated. The physics behind the experimental optical spectra of the composite is discussed.

A theory is developed for the stationary Josephson effect in superconductive constrictions (microbridges).The theory is based on the microscopic Eilenberger equations and is valid for arbitrary temperatures 0<T<Tc. The current-phase relationships I(Q) and critical current Ic(T) obtained differ from the corresponding expressions for a tunnel junction. The difference is greatest at low temperatures and for limitingly pure bridges. In the pure limit l≫a (where l is the free path length; a is the orifice radius) the current is expressed by the formula I(φ)=πΔ0(T)eRNsin(φ/2) th Δn(T)cos(φ/2)2T. The critical current of a pure microbridge at t = 0 is twice the critical current of a tunnel junction with the same normal resistance RN, and the phase-current relationship at the points Q = ±π is discontinuous. The properties of microbridges in the pure (l≫a) and dirty (l≪a) limits are compared.

The possibility of superconductivity is predicted in systems with pairing of spatially separated electrons and holes. Gor’kov and Ginzburg-Landau equations are obtained for the systems under consideration. It is shown that the gap in the elementary excitation spectrum is Δ=vFpae−1/ζ,ζ=4(pa/pa)2(e2/a0)(p02/2m). Here νF is the velocity; p0 is the Fermi momentum; pa = 1/2 a (2a is the spacing between domains with electron and hole conductivity); a0 is the spacing between carriers; m = m1m2/(m2+m2)(m1,m2 are the effective masses of the electrons and holes). The system response to a weak magnetic field is calculated; the currents it causes are J1= − J2 = − {[N(T) e2]/( m1+ m2)c2 }(A1− A2)(A1A2 are the values of the vector potential in domains with electron and hole conductivity; J1J2 are the current densities in the appropriate domains; N(T) is the concentration of superconducting electrons). The presence of a stationary Josephson effect is established, i.e., the possibility of superconductivity in the systems under consideration is proved.

Oxidation of oxyhemoglobin by nitrite is characterized by the presence of a lag phase followed by autocatalysis. The stoichiometry of the overall reaction is described by the following equation: 4HbO2 + 4NO2- + 4H+ = 4Hb+ + 4NO3- + O2 + 2H2O (Hb denotes hemoglobin monomer). During the oxidation, we detected a free radical at g = 2.005, which is very similar to the methemoglobin free radical generated by the reaction with hydrogen peroxide. Nitrosylhemoglobin was not detected. The oxidation was delayed by the addition of KCN or catalase, but was not modified by superoxide dismutase in phosphate buffer. In bistris buffer, however, superoxide dimutase markedly prolonged the lag phase. The results suggest that during the oxidation, the methemoglobin peroxide compound is generated and converts nitrite into nitrogen dioxide by its peroxidatic activity. Nitrogen dioxide oxidizes oxyhemoglobin to methemoglobin and nitrite, yielding the autocatalytic phase.

Mental health represents a huge disease and societal burden and a significant body of research in ubiquitous computing has been devoted to the design of technologies for continuous monitoring, diagnosis, and care of mental health conditions. This paper reviews a decade of research into technologies for mental health, focusing on the use of mobile and wearable technology. The review found 46 systems that are analyzed in a historical context and discussed according to which mental disorder they target, the type of technology, and the type and size of the clinical studies they have been used in. Finally, the paper presents inputs from nine leading researchers in the domain and discuss important technical and clinical challenges in the design of ubiquitous computing technology for the next decade.

Abstract The nature of the characteristic elasticity of rubber and other rubber-like substances has been elucidated by Kuhn and Mark, who showed that it is due to the ability of the thread-like molecules of these substances to fold or curl by free rotation of the separate monomeric elements about the single bonds linking them together into a long hydrocarbon chain. A curled form of these thread-like molecules being more probable than an extended one, they must display a tendency to curl simply because of their heat motion, without any actual forces tending to produce such an effect. As a result, an extension of a rubber-like body (without change of volume), entailing a similar average extension of all the molecular chains constituting it in a definite direction, is resisted by an elastic force proportional to the energy of heat agitation, that is, to the absolute temperature. This situation is quite similar to that which is found in the case of an ideal gas. The pressure exerted by the latter on the walls of the vessel containing it is due, not to a mutual repulsion of the molecules, as was believed long ago, but simply to their heat agitation. The main difference consists in the fact that, instead of a pressure, the heat agitation (free rotation) of the thread-like molecules produces a tension, increasing with the average degree of extension in the given direction. This difference is associated with a difference in the sign of the heating effect produced by a mechanical deformation: whereas a gas is heated on compression and cooled on expansion. In the case of rubber we find an exactly opposite behavior.

Raman spectroscopy was applied to investigate a series of SiC films grown on Si and 6H-SiC substrates by a new method of solid gas phase epitaxy. During the growth characteristic voids are formed in Si at the SiC/Si interface. Raman peak position, intensity and linewidth were used to characterize the quality and the polytype structure of the SiC layers. A large enhancement in the peak intensity of the transverse optical and longitudinal optical phonon modes of SiC is observed for the Raman signal measured at the voids. In addition, scanning electron microscopy and atomic force microscopy were used to investigate the surface morphology of SiC layers.

Nitrides of high-entropy alloys TiZrHfVNb produced using a vacuum-arc cathode evaporation have been studied using scanning electron and atomic force microscopies, energy dispersive, Rutherford ions backscattering, and X-ray diffraction analyses, microhardness measurements, and tribological tests. It has been found that the deposition parameters affect the structure, surface morphology, distribution of elements, mechanical and tribological properties of the coatings under study.

An ansatz has been proposed for setting the initial conditions in the molecular dynamics study of moving discrete breathers in monoatomic close packed crystals. The applicability of the ansatz has been demonstrated for a two-dimensional crystal with Morse interaction.

As career termination is an incisive event in life, it is therefore important to understand the effects of different types of retirement on an athlete’s biography. Thus, the present longitudinal study is concerned with the effects of career termination of professional national team-athletes on the development of psychopathological symptoms, locus of control, self-concept, and mood, with special consideration of the mediator variable “subjective control of event-onset.” Data were collected from 42 professional athletes (17 of whom experienced an unexpected dismissal and 4 voluntarily retired) using standardized questionnaires (SCL-90-R, ASTS, FKK) 10 days before event entrance (baseline-test), 10 days after, 3 weeks after, and 5.5 months after onset of career termination. Although the baseline data did not reveal personality differences between the groups, dismissed athletes showed significantly stronger psychological distress after event onset. They displayed a stronger initial reaction, a more severe crisis, and longer transition periods than the control group. Results are discussed in connection with the combination of social evaluative threat and forced failure during event onset and their strong effects on distress after career termination.

A theory of the nonlinear effects in the electrical conductivity of metallic microbridges is constructed which is based on a model consisting of a hole of radius a in an impermeable partition separating two metallic half-spaces. The electron distribution function, which is a function of the coordinates and which is sharply anisotropic in momentum space, and the electric field distribution in the vicinity of the constriction are found in the limit 1 ⪢ a (where 1 is the electron mean free path). The current–voltage characteristic of the bridge contains nonlinearities induced by inelastic relaxation of electrons on phonons and also on impurities with internal degrees of freedom. The second derivative of the current with respect to voltage is proportional to the constriction spectral function G(ω), which differs from the electron–phonon coupling function normally employed g(ω) by the presence of an additional structure factor K(v,v′) allowing for the geometry of the constriction. At small frequenceis (ω ⪡ ωD) the function G(ω) is proportional to ω4; at frequencies ω ∼ ωD the constriction spectral function G(ω) reflects the singularities of the phonon density of states (including the van Hove singularities). In the case of inelastic scattering of electrons on impurities localized near the hole, the function G(ω) contains peaks corresponding to the discrete impurity excitation levels.

Laser sputtering of solid-state targets in a hydrogen atmosphere has been used to form semiconductor nanoheterostructures. Impurities (Te or Mn) in the form of delta-doped layers obtained by laser sputtering of the corresponding targets in the process of vapor-phase epitaxy using organometallic compounds can be introduced into light-emitting structures based on the InGaAs∕GaAs system to make it possible to control the spectrum and the electroluminescence intensity. Reducing the hydrogen pressure in the reactor to 25–50Torr allows laser deposition to be carried out at reduced temperatures of the epitaxial layers of the base material and makes it possible to obtain GaAs and InAs semiconductors with a high manganese-doping level that demonstrate ferromagnetic properties at room temperature.

The review treats the problem of radiation of relativistic charged particles in matter. The radiation of fast particles in an external field is considered from a unified point of view for an amorphous medium and for a single crystal. The basic attention is paid to the process of radiation in a single crystal where an enhancement of the radiation occurs as compared with an amorphous medium. This effect is shown to be due to the coherent and the interference mechanisms of radiation of relativistic particles in single crystals. First we outline the Born theory (quantum and classical) of coherent radiation of fast particles and show that this theory is valid if the particle propagates through the crystal far from the directions of channeling and if the scattering angle of the particle is small compared with the typical radiation angle of a relativistic particle. Then we show that a violation of these conditions leads to new effects in radiation such as, e.g., the effect of intense radiation of superbarrier and channeled particles, and the effect of suppression of coherent radiation. The comparison of theoretical and experimental results confirms the existence of new effects in the radiation. In conclusion, we review briefly new physical effects that must take place in single crystals at high energies in several other electrodynamical processes.

The phase diagram of solid methane-nitrogen mixtures is investigated by x rays. The boundaries of the maximum reciprocal solubility of the components are determined in the temperature range from 5 °K to the melting point of the mixture. The lattice parameters and molar volumes of the observed phases are studied as a function of temperature and concentration. Negative thermal expansion is found at certain temperatures and concentrations of nitrogen in methane crystals.