Induced astigmatism and concomitant high myopia correction with femtosecond laser-assisted intrastromal MyoRing implantation

Purpose. Analysis of the results of astigmatism correction after penetrating keratoplasty and concomitant high myopia using the MyoRing ring implantation, clinical case as an example.Material and methods. Patient G., 51 years old, underwent surgery to correct astigmatism and concomitant high myopia. MyoRing was implanted in the right eye within corneal transplant limits using femtosecond laser-assisted intrastromal MyoRing implantation. Before the surgery uncorrected visual acuity at the operated eye was 0.01; corrected visual acuity 0.06; spherical component of refraction was (-)6.0 D, cylindrical component was (-)8.0 D. Mean keratometry in the right eye was 43.96 D. Corneal hysteresis was 6.5 mm Hg, corneal resistance factor was 5.5 mm Hg, cornea thickness in center was 529 mkm. The patient was followed up for one year.Results. In 12 months after the surgery visual acuity of the right eye without correction was 0.7 and 0.8 with correction. Spherical component was (-)1.0 D, cylindrical component was (-)2.0 D. Mean keratometry in the right eye was 35.10 D. Corneal hysteresis was 7.2 mm Hg, corneal resistance factor was 6.3 mm Hg, cornea thickness in center was 533 mkm. The patient was satisfied with the result of operation.Conclusion. Femtosecond laser-assisted intrastromal MyoRing implantation for correction induced astigmatism after penetrating keratoplasty and concomitant high myopia is efficient, safe and provides strengthening of biomechanical properties of the cornea besides refractive and visual effect

Correction of postkeratoplastic astigmatism by intrastromal corneal segments implantation using a femtosecond laser

Background. After penetrating keratoplasty, mild to high induced corneal astigmatism was observed in each case. The existing choice of correction of postkeratoplastic astigmatism is aimed at fi nding an individual approach in order to compensate for it and not weaken the biomechanical properties of the corneal graft.The aim: to analyze the clinical, functional, and morphological results of postkeratoplastic astigmatism correction by implantation of intrastromal corneal segments using a femtosecond laser.Methods. 22 patients were examined before and 1 year after surgery. The operation was performed under local anesthesia: stage I – an intrastromal tunnel was formed using a femtosecond laser “Femto Visum” 1 MHz (Optosystems, Russia); stage II – the intrastromal corneal segments were implanted. The results were assessed using standard and special research methods using optical coherence tomography Visante OCT (Zeiss, Germany), keratotopography (Tomey-5, Japan), optical corneal analyzer ORA (Reichert, USA), laser tindalemetry FC-2000 (Kowa, Japan) and confocal microscope Confoscan-4 (Nidek, Japan).Results. Before the operation, uncorrected visual acuity averaged 0.09 ± 0.05, after a year – 0.50 ± 0.16; best corrected visual acuity – 0.30 ± 0.12 and 0.60 ± 0.05 respectively; cylindrical component of refraction – –10.29 ± 3.12 and –2.20 ± 0.64 D respectively; mean keratometry value – 43.59 ± 2.14 and 38.56 ± 1.75 D respectively; corneal hysteresis – 7.92 ± 1.22 and 8.95 ± 1.05 mm Hg respectively; corneal resistance factor – 7.01 ± 1.81 and 8.44 ± 1.44 mm Hg respectively; protein fl ux in the moisture of the anterior chamber – 2.97 ± 0.28 and 3.04 ± 0.24 f/ms respectively; endothelial cell density – 1521 ± 327 and 1475 ± 419 cells/mm2 respectively.Conclusion. Intrastromal corneal segments implantation into a corneal graft using a femtosecond laser has efficiency and safety method in correcting postkeratoplastic astigmatism

ОСНОВАТЕЛЬ НАУЧНОЙ ГИГИЕНЫ – АЛЕКСЕЙ ПЕТРОВИЧ ДОБРОСЛАВИН

The outstanding role of the Russian hygiene founder Alexei Petrovich Dobroslavin in the scientific (experimental) hygiene formation is shown on the basis of historical material.На основе исторического материала показана выдающаяся роль в становлении научной (экспериментальной) гигиены основоположника российской гигиены Алексея Петровича Доброславина

A process-based model of methane consumption by upland soils

This study combines a literature survey and field observation data in an ad initio attempt to construct a process-based model of methane sink in upland soils including both the biological and physical aspects of the process. Comparison is drawn between the predicted sink rates and chamber measurements in several forest and grassland sites in the southern part of West Siberia. CH4 flux, total respiration, air and soil temperature, soil moisture, pH, organic content, bulk density and solid phase density were measured during a field campaign in summer 2014. Two datasets from literature were also used for model validation. The modeled sink rates were found to be in relatively good correspondence with the values obtained in the field. Introduction of the rhizospheric methanotrophy significantly improves the match between the model and the observations. The Q10 values of methane sink observed in the field were 1.2-1.4, which is in good agreement with the experimental results from the other studies. Based on modeling results, we also conclude that soil oxygen concentration is not a limiting factor for methane sink in upland forest and grassland ecosystems.Peer reviewe

ОСОБЕННОСТИ ЭЛЕКТРООСАЖДЕНИЯ КОМПОЗИЦИОННЫХ ПОКРЫТИЙ «НИКЕЛЬ–НАНОПОРОШОК ДИБОРИДА ХРОМА»

The conditions for obtaining composite electrochemical coatings (CEC) have been investigated on the basis of nickel with the use of CrB2 nanopowder as a hardening phase in standard nickel-plating electrolyte. It is established that the maximum saturation of the nickel matrix in using chromium nanoboride takes place when its concentration in the electrolyte is 5–10 kg/m3 that is 8–12 times lower than in using micropowders. CEС microhardness of Ni–CrB2(nano) composition with the content of 0,59–0,65 % hardening phase is 1,16–1,19 times higher than that of Ni–CrB2(micro) coatings containing 2,47–2,86 % boride and 1,64–1,86 times higher than that of the nickel matrix. The optimum conditions of CEC deposition are cathodic current density of 1,0 kA/m2, nanoboride concentration of 5–10 kg/m3 in the electrolyte, pH 5,0–5,5, and temperature of 323 K.Исследованы условия получения композиционного электрохимического покрытия (КЭП) на основе никеля с использованием в качестве упрочняющей фазы нанопорошка CrB2 в стандартном электролите никелирования. Установлено, что максимальное насыщение никелевой матрицы при использовании наноборида хрома происходит при его концентрации в электролите 5–10 кг/м3, что в 8–12 раз ниже, чем при добавке микропорошков CrB2. Микротвердость КЭП состава Ni–CrB2(нано) при содержании в них упрочняющей фазы 0,59–0,65 % в 1,16–1,19 раз выше, чем у покрытий Ni–CrB2(микро), содержащих 2,47–2,86 % борида, и в 1,64–1,86 раз выше, чем у никелевой матрицы. Оптимальными условиями осаждения КЭП являются: катодная плотность тока 1,0 кА/м2, концентрация наноборида в электролите 5–10 кг/м3, рН = 5,0÷5,5 и температура 323 К

FOUNDER OF SCIENTIFIC HYGIENE – ALEXEI PETROVICH DOBROSLAVIN

The outstanding role of the Russian hygiene founder Alexei Petrovich Dobroslavin in the scientific (experimental) hygiene formation is shown on the basis of historical material

Mapping of West Siberian taiga wetland complexes using Landsat imagery: implications for methane emissions

High-latitude wetlands are important for understanding climate change risks because these environments sink carbon dioxide and emit methane. However, fine-scale heterogeneity of wetland landscapes poses a serious challenge when generating regional-scale estimates of greenhouse gas fluxes from point observations. In order to reduce uncertainties at the regional scale, we mapped wetlands and water bodies in the taiga zone of The West Siberia Lowland (WSL) on a scene-by-scene basis using a supervised classification of Landsat imagery. Training data consist of high-resolution images and extensive field data collected at 28 test areas. The classification scheme aims at supporting methane inventory applications and includes seven wetland ecosystem types comprising nine wetland complexes distinguishable at the Landsat resolution. To merge typologies, mean relative areas of wetland ecosystems within each wetland complex type were estimated using high-resolution images. Accuracy assessment based on 1082 validation polygons of 10  ×  10 pixel size indicated an overall map accuracy of 79 %. The total area of the WSL wetlands and water bodies was estimated to be 52.4 Mha or 4–12 % of the global wetland area. Ridge-hollow complexes prevail in WSL's taiga zone accounting for 33 % of the total wetland area, followed by pine bogs or “ryams” (23 %), ridge-hollow-lake complexes (16 %), open fens (8 %), palsa complexes (7 %), open bogs (5 %), patterned fens (4 %), and swamps (4 %). Various oligotrophic environments are dominant among wetland ecosystems, while poor fens cover only 14 % of the area. Because of the significant change in the wetland ecosystem coverage in comparison to previous studies, a considerable reevaluation of the total CH4 emissions from the entire region is expected. A new Landsat-based map of WSL's taiga wetlands provides a benchmark for validation of coarse-resolution global land cover products and wetland data sets in high latitudes

Negative impact of chronic pyelonephritis on the gestation

32 women suffered from chronic pyelonephritis who have wished to interrupt pregnancy in first trimester were investigated. We made the determination of placental (SP-I, β-hGC) and endometrial (glicodelin A, IGFBP-I) proteins concentration in serum, and exposed characteristics proteinsynthesizing function of chorion and endometrium

Net ecosystem exchange and energy fluxes measured with the eddy covariance technique in a western Siberian bog

Very few studies of ecosystem–atmosphere exchange involving eddy covariance data have been conducted in Siberia, with none in the western Siberian middle taiga. This work provides the first estimates of carbon dioxide (CO2) and energy budgets in a typical bog of the western Siberian middle taiga based on May–August measurements in 2015. The footprint of measured fluxes consisted of a homogeneous mixture of tree-covered ridges and hollows with the vegetation represented by typical sedges and shrubs. Generally, the surface exchange rates resembled those of pine-covered bogs elsewhere. The surface energy balance closure approached 100 %. Net CO2 uptake was comparatively high, summing up to 202 gC m−2 for the four measurement months, while the Bowen ratio was seasonally stable at 28 %. The ecosystem turned into a net CO2 source during several front passage events in June and July. The periods of heavy rain helped keep the water table at a sustainably high level, preventing a usual drawdown in summer. However, because of the cloudy and rainy weather, the observed fluxes might rather represent the special weather conditions of 2015 than their typical magnitudes

A process-based model of methane consumption by upland soils

This study combines a literature survey and field observation data in an ad initio attempt to construct a process-based model of methane sink in upland soils including both the biological and physical aspects of the process. Comparison is drawn between the predicted sink rates and chamber measurements in several forest and grassland sites in the southern part of West Siberia. CH4 flux, total respiration, air and soil temperature, soil moisture, pH, organic content, bulk density and solid phase density were measured during a field campaign in summer 2014. Two datasets from literature were also used for model validation. The modeled sink rates were found to be in relatively good correspondence with the values obtained in the field. Introduction of the rhizospheric methanotrophy significantly improves the match between the model and the observations. The Q10 values of methane sink observed in the field were 1.2–1.4, which is in good agreement with the experimental results from the other studies. Based on modeling results, we also conclude that soil oxygen concentration is not a limiting factor for methane sink in upland forest and grassland ecosystems