Diamond photonic crystals for the IR spectral range.

2D photonic crystals formed inside monocrystalline diamond to operate in the IR spectral range are reported. The photonic structures consisting of 150-µm-long graphitized wires arranged in a square matrix with a period of 4 µm were produced by laser writing with ultrashort pulses. Transmittance spectra (λ=1-14 µm) measured for the structures with increasing thickness demonstrate the occurrence of few minima being different for TM and TE polarization modes. Complex refraction index of the laser-modified material was evaluated for the first time in order to be used in computer simulation of the structures.

Polycrystalline diamond UV-triggered MESFET receivers.

Optically triggered UV sensitive receivers were fabricated on polycrystalline diamond as surface channel MESFETs. Opaque gates with asymmetric structure were designed in order to improve charge photogeneration mainly within the gate-drain region. Photogenerated holes contributed to the channel charge by assistance of the local electric field, in such a way improving the current signal at the drain contact. The sensitivity to UV light is demonstrated by using 3 ns wide laser pulses at 193 nm, well over the diamond bandgap. The receiver transient response to such laser pulses shows that the photogeneration process is only limited by the pulse rise time and charge collection at the drain contact completed in a time scale of a few nanoseconds. Such opaque gate three-terminal devices are suitable for application in emerging photonic technologies, for power-management system optical receivers, where copper wires and EM shielding can be replaced by lightweight optical fibers.

Surface channel MESFETs on hydrogenated diamond.

Metal­semiconductor field effect transistors (MESFETs) based on hydrogen terminated diamond were fabricated according to different layouts. Aluminum gates were used on single crystal and low-roughness polycrystalline diamond substrates while gold was used for ohmic contacts. Hydrogen terminated layers were deeply investigated by means of Hall bars and transfer length structures. Room temperature Hall and field effect mobility values in excess of 100 cm2 V⁻¹ s⁻¹ were measured on commercial and single crystal epitaxial growth (100) plates by using the same hydrogenation process. Hydrogen induced two-dimensional hole gas resulted in sheet resistances essentially stable and repeatable depending on the substrate quality. Self-aligned 400 nm gate length FETs on single crystal substrates showed current density and transconductance values>100 mA mm⁻¹ and >40 mS mm⁻¹, respectively. Devices with gate length LG=200 nm showed fMax=26.4 GHz and fT=13.2 GHz whereas those fabricated on polycrystalline diamond, with the same gate geometry, exceeded fMax=23 GHz and fT=7 GHz. This work focused on the optimization of a self-aligned gate structure with respect to the fixed drain-to-source structure with which we observed higher frequency values; the new structure resulted in improvement of DC characteristics, better impedance matching and a reduction in the fMax/fT ratio.

Field electron emission and nanostructural correlations for diamond and related materials.

Results are presented on a complex study of field electron emission (FEE) and structural correlations for nanocrystalline diamond and nitride films. It was found that all the samples studied showed similar dependences of the Fowler-Nordheim work function and effective emitting area on the threshold emission field. Besides it was generally observed that FEE occurred at nanosized regions on the boundary of high and low conducting areas, and peaks of the emission intensity were associated with a lowered surface electron potential. Based on the experimental data, the following mechanism of low-FEE from the materials studied can be supposed. Electrons are transferred from the conducting channel into a vacuum through the low-dimensional region where the emission probability is high due to the quantum well effect. A physical model of the electron escape from a quantum well was analyzed. As follows from the estimations, the quantum size effect, being combined with a moderate field enhancement (the field enhancement factor beta=10-100), allows us to explain the observed variation in the energetic parameters for the samples studied. The function of the insulating grains is mainly to support the conducting channels in the sample body. Also, the grains can fulfill an additional function of the heat sink.

[A calcium channel in the rat liver inner mitochondrial membrane. Effective diameter and selectivity under various conditions]. / Kal'tsievyi kanal vnutrennei membrany mitokhondrii pecheni krysy. Effektivny diameter i selektivnost' v razlichnykh usloviiakh.

The pore with an effective diameter of 6.0 A is a Ca(2+)-channel of the inner mitochondrial membrane. Transport of nonelectrolytes through the pore is inhibited by ruthenium red, a specific Ca2+ transport inhibitor, and by polyanions which bind to the positively charged regions in the pore localized on the outer side of the inner mitochondrial membrane. The selectivity of Ca2+ ion transport into intact mitochondria is due to the binding of Ca2+ ions by the glycoprotein at the mouth of the pore as well as to electrostatic interactions of monovalent cations (electrostatic repulsion) and Cl- ions (strong binding) with the positively charged region of the ion-selective filter of the pore. Under normal conditions SCN- and NO3- ions are transferred through the pore at a high rate. Removal of Mg2+ ions and the rise in pH diminish the electrostatic repulsion of the monovalent cations and Cl- ions from the positively charged region of the pore. Depending on conditions, the pore can function as a monovalent ion transport system or as a mechanism of Cl- ion transfer through the inner mitochondrial membrane.

[Oxidative phosphorylation uncoupling in hyperthyroidism as a result of activating cyclosporin-sensitive pores in the inner mitochondrial membrane by water soluble modulators from rat liver cytoplasm]. / Razobshchenie okislitel'nogo fosforilirovaniia pri gipertireoze kak sledstvie aktivatsii tsiklosporinchuvstvitel'noi pory vo vnutrennei membrane mitokhondrii vodorastvorimymi moduliatorami iz tsitoplazmy pecheni krysy.

Small concentrations of low molecular weight modulators of the functional state of rat liver cytoplasm mitochondria, which uncouple oxidative phosphorylation, induce phosphate-dependent transport of potassium and hydrogen ions. In contrast, high concentrations of these compounds induce nonspecific transport of monovalent cations and sucrose (K+ > H+ > Na+ > or = Li+ > sucrose). The effect of cytoplasmic modulators on oxidative phosphorylation and permeability of the inner mitochondrial membrane in inhibited by cyclosporin A and controlled by physiological concentrations of Ca2+. It is assumed that ion transport across the inner mitochondrial membrane in the presence of cytoplasmic modulators is implemented by the same cyclosporin-sensitive transport system which in damaged mitochondria functions as a nonspecific pore.

[Effective diameter of pores in rat liver mitochondria inner membrane and selectivity of transport of monovalent cations with a submicromolar concentration of Ca2+ ions or A23187 and EDTA]. / Effektivnyi diameter pory vo vnutrennei membrane mitokhondrii pecheni krysy i selektivnost' transporta odnovalentnykh kationov pri deistvii submikromoliarnykh kontsentratsii ionov Ca2+ ili A23187 i EDTA.

Studies of swelling of rat liver mitochondria in isoosmotic solutions of nonelectrolytes in the presence of respiration inhibitors revealed that submicromolar concentrations of Ca2+ increase the diameter of pores in the inner mitochondrial membrane--from 5.5-6.0 A (10(-8) M Ca2+) up to 7.5 A (3 x 10(-7) M Ca2+) and 8.0-8.5 A (6 x 10(-7) M Ca2+); these increases are prevented by cyclosporin A. The inner mitochondrial membrane with an effective pore diameter of 7.5 A is readily permeable for potassium but not for sodium ions, although with an increase in the effective pore diameter up to 8.0-8.5 A the selectivity of the K(+)-Na+ channel decreases. A conclusion is drawn that in the presence of submicromolar concentrations of Ca2+ the conductivity of the cyclosporin-sensitive pore for monovalent cations increases in the following order: K > Na > Li.

Recanalisation of occluded peripheral arteries by excimer laser.

Laser recanalisation was attempted in 24 patients with total segmental occlusions of the lower extremity arteries and the aortic arch branches. All patients were men aged 40-82 years, in 20 the lesions were caused by atherosclerosis, in three by Buerger's thromboangiitis and in one by postembolic occlusion. Angioplasty was performed using excimer lasers with a wavelength of 308 nm and with monofiber waveguides in the transcutaneous transcatheter mode. Recanalisation of the vessel throughout the length of the obliterated segment was successful in 13 out of 24 patients. In all patients with thromboangiitis, energy losses were less than in atherosclerotic occlusions and no problems were experienced in patients with severe calcification. A high percentage of failures is a result of imperfect technology and low effectiveness of control, this must be improved. The Vishnevsky Institute of Surgery in collaboration with the Institute of General Physics has been developing a method of recanalisation of occluded arteries using excimer laser radiation. This paper is a preliminary analysis of our first clinical results.

[Regulation of thyroid hormones of the interaction of mitochondria with low-molecular weight cytoplasmic mediators, induced by phosphate- dependent transport of K+ and H+ ions through the mitochondrial inner membrane]. / Reguliatsiia tireoidnymi gormonami vzaimodeistviia mitokhondrii s nizkomolekuliarnymi tsitoplazmaticheskimi mediatorami, indutsiruiushchimi fosfatzavisimyi transport ionov K+ i H+ cherez membranu mitokhondrii.

In vivo thyroid hormones control the binding to mitochondria of low molecular weight water-soluble cytoplasmic mediators that are capable to induce oxidative phosphorylation uncoupling, by increasing the sensitivity of mitochondria to the effects of these mediators. In hyperthyroid rat liver mitochondria cytoplasmic mediators stimulate the phosphate-dependent transport of K+ and H+ in a greater degree than in liver mitochondria of control rats. The increase in the oxidative phosphorylation uncoupling by cytoplasmic mediators is one of mechanisms of thermogenesis stimulation by thyroid hormones.

[Isolation of low molecular weight cytoplasmic regulators from the rat liver inducing the electrophoretic transport of K+ ions and phosphate across the inner mitochondrial membrane]. / Vydelenie nizkomolekuliarnykh tsitoplazmaticheskikh reguliatorov iz pecheni krysy, indutsiruiushchikh lektroforeticheskii transport ionov K+ i fosfata cherez vnutrenniuiu membranu mitokhondrii.

A water-soluble thermostable factor from rat liver cytoplasm whose activity decreases during starvation, causes the uncoupling of oxidative phosphorylation and stimulates pyruvate oxidation in rat liver mitochondria. The activity of this factor is insensitive to pronase treatment. Gel filtration and ion-exchange chromatography resulted in three low molecular weight water-soluble fractions which bear a negative charge at alkaline values of pH and induce electrophoretic transport of K+ and phosphate across the inner mitochondrial membrane. The effect of this factor on K+ transport is manifested at pH less than or equal to 7.0, that on phosphate transport-at pH 6.5-7.6.

[Laser surgery in occlusive diseases of peripheral arteries]. / Lazernaia dezobliteratsiia perifericheskikh arterii pri okkliuziruiushchikh porazheniiakh.

The first experience with the use of an excimeric laser in the treatment of 24 patients with segmental occlusion of the peripheral arteries is discussed. It proved possible to recanalize the obstructed segment of the vessel for its whole distance in 13 patients. Analysis of the complications shows that further technological development of the method is necessary. Hemodynamic adequacy of restoration of the vascular lumen by laser recanalization in combination with balloon dilatation is demonstrated. Significant decrease of the risk of operative intervention, accelerated rehabilitation of patients, and an essential economical effect may be the advantages of the method.

Possible mechanism for laser-induced two-dimensional periodic structures by analogy with the Bénard effect.

An explanation is presented for the formation of periodic structures on solid surfaces under powerful laser irradiation through an analogy to the Bénard effect.

[Regulation of oxidative phosphorylation, K+ ions transport and the volume of mitochondrial matrix by cytoplasmic glycopeptide and Ca2+ ions]. / Reguliatsiia okislitel'nogo fosforilirovaniia, transporta ionov K+ i ob''ema matriksa mitokhondrii tsitoplazmaticheskim glikopeptidom i ionami Ca2+.

A thermostable low molecular weight glycopeptide containing syalic acids, which uncouples mitochondrial oxidative phosphorylation, has been detected, isolated and purified from rat liver cytoplasm. In the presence of the glycopeptide, oxidative phosphorylation in rat liver mitochondria is uncoupled by low physiological concentrations of Ca2+, which otherwise do not have any appreciable effect on the mitochondria. Oxidative phosphorylation uncoupling by the glycopeptide is accompanied by an increase of the mitochondrial volume. This process has a limited amplitude and is regulated by changes in Ca2+ concentration in the extramitochondrial space. The glycopeptide has been shown to induce K+ transport across the inner mitochondrial membrane, this effect is enhanced by Ca2+.

[Etiology of salmonellosis in swine raised commercially]. / Kum etiologiiata na salmonelozite po svinete, otglezhdani pri promishleni usloviia.

A total of 25,561 samples from swine (cadavers, internal organs, rectal swabs, feed, and washings of premises) were investigated microbiologically over the 1981-1985 period via routinely employed methods for the isolation and typing of Salmonella organisms, following the Kauffmann-White pattern. Tested was the susceptibility of 411 strains by the disk-diffusion method, using drugs of the general practice, and the results were recorded after Bauer. In 5.32 per cent of the samples 19 Salmonella serotypes of the B. C. D, and E groups were isolated. Greatest in the etiology of salmonelloses was still the relative share of S. cholerae suis (85.22%), represented by the two-phase var. america and the autochthonous var. kunzendorf. Second ranked S. typhimurium--5.14%, followed by S. agona--2.20%, S. menden--1.25%, S. thompson--1.18%, S. derby--1.10%, S. bovis-morbificans--0.81%, and others. A change was ascertained in the serotypes isolated from pigs with regard to the exotic types. Sensitive to gentamycin proved 89.9%, to chloramphenicol--79.1%, to carbenicillin--71%, to kanamycin--70%, etc; 75% were resistant to ampicillin, 54.6%--to streptomycin, 51.3%--to tetracycline, and 33.8%--to furazolidone.

[Electrogenic transport of bicarbonate ions through the internal mitochondrial membrane induced by cytoplasmic glycopeptide]. / Elektrogennyi transport ionov bikarbonata cherez vnutrenniuiu membranu mitokhondrii, indutsirovannyi tsitoplazmaticheskim glikopeptidom.

Cytoplasmatic glycopeptide-induced bicarbonate ion electrogenic transport through mitochondrial membrane has been studied. Glycopeptide, described earlier as a factor increasing inner mitochondrial membrane permeability for phosphate ions, has been also shown to induce bicarbonate ion electrogenic transport through inner mitochondrial membrane. HCO3- ion transport, induced by cytoplasm glycopeptide is realized by pH-dependent pore. The interrelation of cytoplasm glycopeptide with mitochondria is regulated by mitochondrial energization.