Acousto-Optics 2017: introduction to the feature issue.

The editors of Acousto-Optics 2018 provide an overview of the featured papers in the context of the 13th School of Acousto-Optics and Applications from which the articles were drawn.

Interference of phase-shifted chirped laser pulses for secure free-space optical communications.

A new method concerning secure free-space communications by means of chirped laser pulse interference is proposed. Physical-layer security of the link is ensured by encoding the data in a relative phase difference between two spatially separated beams. The possible architecture of the dual-node link is discussed based on acousto-optic elements for signal modulation and detection.

Double acousto-optic deflector system for increased scanning range of laser beams.

A new laser scanning system is presented based on two wide-band acousto-optic deflectors. The interaction medium is tellurium dioxide. Anisotropic interactions take place under two different tangential phase matching configurations in such a way that the acousto-optic bandwidths add up. We demonstrate the feasibility of such a cascade deflection system for the wavelength of λ=514nm. The total frequency bandwidth is Δf=100MHz, equally distributed between the two acousto-optic deflectors. The total angular scan at the output is Δθ=4.4° leading to 125 resolvable spots for a 1mm truncated Gaussian beam.

Acoustic field structure simulation in quasi-collinear acousto-optic cells with ultrasound beam reflection.

Ultrasound wave reflection from one of the crystal faces is the convenient way to arouse the acoustic beam with a desired propagation direction in acousto-optic cells with collinear and quasi-collinear interaction geometries. The reflection process effects on the ultrasound field amplitude and phase structure. The method to simulate the reflected finite ultrasound beam structure in the case of acoustically anisotropic media is presented in this paper. The investigation is carried on the example of two quasi-collinear acousto-optic cells fabricated on the base of tellurium dioxide crystal. The cells have special geometry that allows to obtain extremely long acousto-optic interaction length and to achieve unprecedented spectral resolution. The influence of reflection process in the acousto-optic diffraction characteristics was also examined.

Influence of acoustic anisotropy in paratellurite on quasicollinear acousto-optic interaction.

The influence of paratellurite acoustic anisotropy on the quasicollinear acousto-optic diffraction characteristics was examined. In the presented case the quasicollinear geometry of acousto-optic diffraction is realized with the use of acoustic beam reflection from one of the crystal surfaces. The simulations were based on the solution of acoustic beams propagation problem for anisotropic media previously presented in Balakshy and Mantsevich (2012). It is shown that media inhomogeneity affects the distribution of the acoustic energy in the ultrasound beam and the shape of wave fronts. The acoustic beam structure influences the characteristics of quasicollinear acousto-optic diffraction causing transformation of acousto-optic device transmission function shape and reducing the diffraction efficiency.

[Diagnosis and prevention of parasitosis in the armed forces of the Southern Military District].

The results of the sanitary-parasitological studies, performed in 2010 in the Southern Military District. Detection of excited-makers parasitoses in soldiers was 1.5%. Allocated to eight species of helminthes and 4--the simplest. A set of preventive measures tick parasites in the army.

[Comparative analysis of retinotomographic and histological examinations of retina in health and primary open-angle glaucoma].

Comparative analysis of retinal structure was performed in patients with POAG and control healthy group using spectral OCT and histology. An apparent similarity of tomographic and histological patterns of retinal changes was found in patients with POAG. These results make OCT potentially appropriate method for vital examination of retinal structure in glaucomatous eyes including early stages of the disease. Degeneration of all retinal layers is revealed. Blood flow deficiency due to sclerosis and hyalinosis of uveal vessels is considered to be an immediate cause of outer and intermediate retinal layers degeneration.

[Isoelectrofocusing and photocolorimetry for determination of glycated hemoglobin (HbA1c)].

Analytical reliability of a new method for determination of glycated hemoglobin (HbA1c) has been evaluated. The method is based on hemoglobin isolation during isoelectrofocusing followed by acidic hydrolysis and photocolorimetry of furfurol formed after its reaction with thiobarbituric acid. At diabetic and non-diabetic levels inter- and intraserial reproducibility varied from 6 to 21%. Sensitivity of this method was determined using physiological solution and 50% albumin.

TEM and HREM of diamond crystals grown on Si tips: structure and results of ion-beam-treatment.

Diamond single crystals were grown on the silicon whiskers by a hot filament chemical vapor deposition technique at the filament temperature about 2100 degrees C and the temperature of support 800 degrees C. Specimens were examined by SEM, TEM, HRTEM and SAED. When the filament temperature was about 1900 degrees C globular polycrystalline diamond particles were grown. At a support temperature more then 800 degrees C SiC nanoparticles were formed. To investigate the ion etching process of the silicon tip/diamond system, tips were treated with an Ar(+) beam with energy up to 30 kV. The results depend on fluence: at 4 x 10(18)ion/cm(2) diamonds and partially Si tips were destroyed, amorphous layer was formed (sometimes with nanometric size fragments of diamond); at 1 x 10(18)ion/cm(2) sharpened diamonds (radius of curvature about 20 nm) covered with amorphous layer (radius about 80 nm) probably with nanoclusters of diamond were observed; at 4.4 x 10(17) ion/cm(2) there was no visible tip sharpening but formation of amorphous thick layer occurred. The emission characteristics of Si tips covered with diamond were improved due to ion treatment. Since such tips in our case were covered with amorphous layer containing nanometric size fragments of diamond, we suppose this layer is responsible for electron emission improvement.

[Selective intra-arterial use of small doses of thienam and vasaprostanin the treatment of suppurative diseases of the foot in patients with diabetes mellitus]. / Selektivnoe vnutriarterial'noe primenenie malykh doz tienama i vazaprostana v lechenii gnoinykh zabolevanii stopy u bol'nykh sakharnom diabete.

The authors present data of using the selective intraarterial infusion of Thienam and Vasaprostan for treatment of purulent diseases of the foot in 70 patients with diabetes mellitus. The microsurgical method was used. The proposed method is thought to be expedient and highly effective.

[Thyroid gland ectopia at the base of the tongue]. / Ektopiia shcitovidno i zhelezy v osnovanie iazyka.

At initial examination ulcer at the base of the tongue in a female of 25 years was diagnosed as a tumor. Further morphological investigation revealed the presence of the thyroid tissue while it was absent at the site of normal thyroid location. Most appropriate clinical and diagnostic approaches to this case are described which helped avoid unjustified surgery and related grave complications.

[Rehabilitation of patients suffering from closed spinal trauma with damage to the spinal cord]. / Reabilitatsiia bol'nykh pri zakrytoi travme pozvonochnika s povrezhdenniem spinnogo mozga.

Results of complex rehabilitative treatment of 652 patients with above kind of pathology are examined. Outcomes of motor mobility depending on the level and severity of the injury are shown. In spine-spinal cord injury 77.3% of patients could walk using supplementing devices. The percent of I group invalidity depending on the level of spinal cord injury varies from 74.6-92.7%, II group invalidity--0.8-7.5%, III group invalidity--0.8-3.5%.

[Sociomedical characteristics of population groups differing in the frequency of alcohol consumption (population research)]. / Nekotorye mediko-sotsial'nye kharakteristiki grupp naseleniia, razlichaiushchikhsia po chastote upotrebleniia alkogolia (populiatsionnoe issledovanie).

A representative sample of the population of one Moscow district (people aged 35-64) was studied. All the examined subjects were asked, how often they used alcohol. Only 31.1% of women and 14.3% of men used no alcohol at all. The highest was the percentage of persons using alcohol several times a year: 42.1% of men and 60% of women. Men using alcohol several times a week proved to have arterial hypertension more often than those not using alcohol. Among men aged 55-64 using alcohol several times a week nobody had normal blood pressure. The more alcohol people used, the less they cared for their health and the more rarely they visited a doctor.