ABSTRACT
The description of the magnetic properties of amorphous alloys and comparison of the model evaluation with experimental data have been carried out in terms of the magnetic theory of disordered systems (Biryukov's theory). The hysteresis loops for a number of amorphous metallic glasses have been investigated and it also has been shown that Biryukov's hypothesis about the weak correlation between spin and electrostatic components is true for the amorphous magnetic system that permits to interpret collectively the results of different magnetometric experiments.
ABSTRACT
Static and time-resolved mid-infrared spectroscopy of ferromagnetic single crystal Hg0.95Cd0.05Cr2Se4 was performed below the absorption edge, in order to reveal the origin of the electronic transitions contributing to the magneto-optical properties of this material. The mid-infrared spectroscopy reveals a strong absorption peak around 0.236 eV which formerly was assigned to a transition within the selenide-chromium complexes ([Formula: see text] Se-Cr2+). To reveal the sensitivity of the transition to the magnetic order, we performed the studies in a temperature range across the Curie temperature and magnetic fields across the value at which the saturation of ferromagnetic magnetization occurs. Despite the fact that the Curie temperature of this ferromagnetic semiconductor is around 107 K, the intensity of the mid-infrared transition reduces substantially increasing the temperature, so that already at 70 K the absorption peak is hardly visible. Such a dramatic decrease of the oscillator strength is observed simultaneously with the strong red-shift of the absorption edge in the magnetic semiconductor. Employing a time-resolved pump-and-probe technique enabled us to determine the lifetime of the electrons in the excited state of this optical transition. In the temperature range from 7 K to 80 K, the lifetime changes from 3 ps to 6 ps. This behavior agrees with the phenomenon of giant oscillator strength described earlier for weakly bound excitons in nonmagnetic semiconductors.
ABSTRACT
Electrostatic interaction of plastocyanin and cytochrome f in the process of protein-protein complex formation was investigated by computer simulation methods. It was shown that long-range electrostatic interaction promotes energetically favorable mutual orientation of protein molecules at distances between their cofactors shorter than 5 nm. At distances shorter than 3 nm, these electrostatic interactions lead to a significantly detectable increase in the rate of convergence of the cofactors.
Subject(s)
Cytochromes f/chemistry , Diffusion , Plant Proteins/chemistry , Plastocyanin/chemistry , Static Electricity , Brassica napus , Computer Simulation , Copper/chemistry , Models, Chemical , Oxidation-Reduction , Software , Solutions , Solvents/chemistry , Spinacia oleraceaABSTRACT
The Brownian dynamics method is used for qualitative analysis of events leading to formation of a functionally active plastocyanin-cytochrome f complex. Intermediate states of this process are identified by density-based hierarchical clustering. Diffusive entrapment of plastocyanin by cytochrome f is a key point of the suggested putative scenario of protein-protein approaching. Mobility of plastocyanin is characterized for different values of protein-protein electrostatic interaction energy.
Subject(s)
Cytochromes f/chemistry , Electrons , Molecular Dynamics Simulation , Plastocyanin/chemistry , Binding Sites , Brassica rapa/chemistry , Cluster Analysis , Diffusion , Electron Transport , Oxidation-Reduction , Protein Binding , Protein Structure, Secondary , Protein Structure, Tertiary , Spinacia oleracea/chemistry , Static Electricity , ThermodynamicsABSTRACT
The application of Brownian dynamics for simulation of transient protein-protein interactions is reviewed. The review focuses on theoretical basics of Brownian dynamics method, its particular implementations, advantages and drawbacks of the method. The outlook for future development of Brownian dynamics-based simulation techniques is discussed. Special attention is given to analysis of Brownian dynamics trajectories. The second part of the review is dedicated to the role of Brownian dynamics simulations in studying photosynthetic electron transport. Interactions of mobile electron carriers (plastocyanin, cytochrome c6, and ferredoxin) with their reaction partners (cytochrome b6f complex, photosystem I, ferredoxin:NADP-reductase, and hydrogenase) are considered.
Subject(s)
Biophysical Phenomena , Cytochromes c6/chemistry , Photosynthesis , Plastocyanin/chemistry , Cytochromes f , Electron Transport , Ferredoxins/chemistry , Kinetics , Models, Molecular , Molecular Dynamics Simulation , Photosystem I Protein Complex , Protein ConformationSubject(s)
Air Ionization , Conservation of Natural Resources , Health Resorts , Plants , Russia , TreesABSTRACT
In 2002 the analysis of parasitosis incidence in the servicemen of North-Caucasian military district was conducted in order to evaluate the risk of its spread and to optimize the ways of its prevention at the territory studied. One of the most important directions of prophylactic work is the training of specialists (parasitologists, laboratory physicians, epidemiologists, laboratory assistants) in the field of parasitology and early diagnosis of parasitogenic diseases in servicemen.
Subject(s)
Military Personnel , Parasitic Diseases/epidemiology , Humans , Incidence , Military Hygiene , Parasitic Diseases/etiology , Russia/epidemiologyABSTRACT
Waveguides in LiNbO3 are realized by a soft proton exchange (SPE) process with use of a melt of stearic acid highly diluted by lithium stearate. No phase transitions are formed when alpha-phase waveguides are obtained by SPE. The alpha-phase presents the same crystalline structure as that of pure LiNbO3 crystal, and it maintains the excellent nonlinear and electro-optical properties of the bulk material. The kinetics of the SPE method is studied by the use of secondary-ion mass spectrometry and prism-coupling techniques. The hydrogen effective diffusion coefficient as well as the self-diffusion coefficients of H+ and Li+ ions are determined as a function of the proton-exchange temperature for X-cut LiNbO3.
ABSTRACT
Diagnostic methods using a Pulsar radar measuring computer unit have been developed. The methods are based on the contactless recording of respiratory parameters and pulse and they evaluate human body's functions in real time from the measurements of the duration of cardiac rhythms and calculate the differential function of their distribution and the spectrum of a cardiac rhythmogram.
Subject(s)
Diagnosis, Computer-Assisted , Monitoring, Physiologic , Adolescent , Adult , Age Factors , Algorithms , Cardiovascular Diseases/diagnosis , Cardiovascular Diseases/prevention & control , Child , Child, Preschool , Diagnosis, Differential , Heart/physiology , Heart/physiopathology , Heart Rate/physiology , Humans , Kyphosis/diagnosis , Lordosis/diagnosis , Microcomputers , Myocardial Ischemia/diagnosis , Myocardial Ischemia/physiopathology , Posture , Risk Factors , Spinal Curvatures/diagnosis , Spinal Curvatures/prevention & controlABSTRACT
By using x-ray diffraction and optical waveguide characterization, it has been shown that proton-exchanged layers on Z-cut LiNbO(3) can have as many as seven different crystallographic phases that are stable at room temperature. This study allows us to establish some correlation between fabrication parameters and the crystalline structure, the index profiles, and the propagation losses of waveguides prepared by this process.
Subject(s)
Neurilemmoma/pathology , Stomach Neoplasms/pathology , Diagnosis, Differential , Female , Gastrointestinal Hemorrhage/etiology , Gastrointestinal Hemorrhage/surgery , Humans , Middle Aged , Neurilemmoma/complications , Neurilemmoma/surgery , Stomach Neoplasms/complications , Stomach Neoplasms/surgeryABSTRACT
Macro- and microscopic alterations of organs in 115 patients dead from acute cholecystitis at the age from 23 to 88 were studied with special reference to clinico-laboratory findings. As a rule, there were changes in several organs, especially in the vessels and heart (99,1%), liver (93,1%), lungs (75,5%), kidneys (63,4%). A conclusion is made that the main causes of death are hepatic insufficiency (65,2%), peritonitis (13,9%), pancreanecrosis (7,8%), thromboembolism (6,1%). Other causes made 7%.
