Contact Melting in Simple Eutectic System

The growth of the liquid interlayer in the system lead-tin at 463 K is studied experimentally in the nonstationary diffusion process of contact melting. The contact melting was carried out between pure tin and solid solution of tin in lead (0, 5.9, 11.5, 17.8, 24.8 mol. % Sn). The results indicate that the concentration range of the liquid interlayer corresponds to the interval of homogeneity of the liquid phase in the phase diagram at the experiments temperature. It is shown that the solid solution corresponding to the solidus near the liquid/crystal interface can not be generated by the diffusion of atoms from the liquid into the crystal. An explanation is offered that the solid solution of solidus composition at the liquid/crystal interface occurs as a result of the precipitate from the metastable (supersaturated by lead) melt

Optical coherence tomography angiography in the study of retinal blood flow in pregnant women with diabetes

Purpose. To study retinal blood flow in pregnant women with diabetes using optical coherence tomography angiography (OCTA).Material and methods. 60 pregnant women were examined: 24 women had type 1 and 2 diabetes (T1D and T2D) and 36 healthy women with physiological pregnancy consisted the control group. Pregnant women with diabetes were examined in three trimesters of pregnancy, the control group – in the third trimester. OCTA imaging was performed using the RTVue XR Avanti OCT 6×6 mm Angio Retina scan protocols (Optovue, USA). The vascular density (VD), vascular density in the fovea (VDF), and foveal avascular zone (FAZ) area in the superficial capillary plexus were studied.Results. In the third trimester, VDF in pregnant women with diabetes was significantly less than in the control group, in the absence of differences in VD and FAZ area. VD was significantly lower, and FAZ area was significantly higher in pregnant women with diabetic retinopathy (DR) than in pregnant women with diabetes without DR. There were no significant differences in the values of blood flow parameters in the groups of pregnant women with diabetes, regardless of underwent them the laser coagulation of the retina. At analyzing the values of VD, VDF, FAZ area in pregnant women with diabetes in different trimesters of pregnancy, statistically significant differences were not observed.In 11 pregnant women with DR areas of retinal nonperfusion were revealed, which in 6 patients tended to expand during pregnancy. In 2 patients with T1D without DR in the third trimester areas of nonperfusion were identified.Conclusion. Obtained data have practical importance for the diagnosis of DR manifestations during pregnancy. OCTA is a valuable diagnostic method that allows non-invasive diagnostics of the presence of areas of retinal nonperfusion in the absence of ophthalmoscopic signs of DR in pregnant women with diabetes, as well as assess the state of areas of retinal nonperfusion during pregnancy in patients with DR

The state of indicators of the angio-OCT of the macular area in pregnant women with preeclampsia in conjunction with the content of the factor of endothelial dysfunction, their importance for predicting vascular retinal pathology in the postpartum period

Purpose. Clinical assessment of the hemodynamic state of the macula in pregnant women with preeclampsia in conjunction with the content of endothelial dysfunction factors, their importance in predicting vascular retinal pathology in the postpartum period.Material and methods. The main group consisted of 46 pregnant women with preeclampsia (PE) from 19 to 40 years. 36 women had a moderate degree of PE, and 10 women had a severe degree. The 1st comparison group included 20 pregnant women with a physiological course of pregnancy, from 18 to 38 years. The 2nd comparison group included 16 non-pregnant women with occlusions of the branches of the central retinal vein (CRV), aged 34 to 45 years. The control group consisted of 20 healthy, non-pregnant women from 19 to 38 years. All patients underwent determination of the level of endothelin-1 (E) in the lacrimal fluid (LF), the state of hemodynamics of the macular area was investigated using optical coherent tomography with angiography function (angio-OCT).Results. The highest values of the average level of E in LF occurred in the main group and in the 2nd comparison group (2.5±1.1 and 2.6±0.4 ng / ml, respectively). In the 1st comparison group in the 3rd trimester of pregnancy, the indicators of the total average density of the superficial vascular plexus in the macular region (DS), the density of the superficial vascular plexus in the fovea (DF), the density of the superficial vascular plexus in the parafova (DP), the area of the retinal avascular area (NFA) and subfoveal thickness of the choroid (CTX) had statistically significant differences from the control (p<0.01), but after 6–9 months after birth, these differences disappeared, although the difference in DS, DP values remained.Conclusion. In women with PE in the 3rd trimester of pregnancy, there was a statistically significant increase in E level in the LF and the deterioration of the angio-OCT of the macular ar ea

Diabetic Retinopathy and Pregnancy

Purpose: analysis of clinical cases of different course of diabetic retinopathy in pregnancy.Patients and methods. The article presents 5 clinical cases of different course of diabetic retinopathy in pregnancy: absence of manifestation, stable course and progression to macular edema and aggressive proliferation.Results. The reasons for progression of diabetic retinopathy during pregnancy were analyzed. The most important were the compensation of diabetes mellitus in preconception period and throughout pregnancy, the severity of retinopathy, and the presence of concomitant pathology. It is emphasized that timely detection of progression signs of retinopathy and laser coagulation during pregnancy makes it possible to stabilize the course of disease and improve visual prognosis. Thus, the monitoring of pregnant women with diabetes mellitus requires an individual approach and careful dynamic observation during pregnancy and in postpartum period. Timely laser coagulation in progression of retinopathy can contribute to preservation of visual functions.Conclusions. Clinical course of diabetic retinopathy in pregnancy is variable: no manifestation, stabilization, progression. Progression of diabetic retinopathy during pregnancy is determined by many factors, in particular, the compensation of diabetes mellitus in preconception period and throughout pregnancy, the severity and stabilization of retinopathy as results of treatment in preconception period, the presence of concomitant pathology. Timely detection of signs of diabetic retinopathy progression and its treatment, particularly laser coagulation of the retina, during pregnancy allows stabilizing the course of disease. There may be an aggressive course of diabetic retinopathy with progression in postpartum period, in connection with which, active monitoring of patients with retinopathy after childbirth is required

Contact Melting in Simple Eutectic System

The growth of the liquid interlayer in the system lead-tin at 463 K is studied experimentally in the nonstationary diffusion process of contact melting. The contact melting was carried out between pure tin and solid solution of tin in lead (0, 5.9, 11.5, 17.8, 24.8 mol. % Sn). The results indicate that the concentration range of the liquid interlayer corresponds to the interval of homogeneity of the liquid phase in the phase diagram at the experiments temperature. It is shown that the solid solution corresponding to the solidus near the liquid/crystal interface can not be generated by the diffusion of atoms from the liquid into the crystal. An explanation is offered that the solid solution of solidus composition at the liquid/crystal interface occurs as a result of the precipitate from the metastable (supersaturated by lead) melt

Contact Melting in Simple Eutectic System

The growth of the liquid interlayer in the system lead-tin at 463 K is studied experimentally in the nonstationary diffusion process of contact melting. The contact melting was carried out between pure tin and solid solution of tin in lead (0, 5.9, 11.5, 17.8, 24.8 mol. % Sn). The results indicate that the concentration range of the liquid interlayer corresponds to the interval of homogeneity of the liquid phase in the phase diagram at the experiments temperature. It is shown that the solid solution corresponding to the solidus near the liquid/crystal interface can not be generated by the diffusion of atoms from the liquid into the crystal. An explanation is offered that the solid solution of solidus composition at the liquid/crystal interface occurs as a result of the precipitate from the metastable (supersaturated by lead) melt

Vascular complications of the eye in the late postpartum period of postponed preeclampsia

The article presents the main pathogenetic mechanisms of endothelial dysfunction formation in complicated pregnancy and vascular pathology. The possible consequences of postponed preeclampsia are described. The performed analysis of the literature allows to approve that preeclampsia should be considered as a pathology threatening an increased risk of the vascular eye pathology formation, both in the short and in the long-term periods after childbirth

CLINICAL SIGNIFICANCE OF MICROALBUMINURIA IN FORMATION OF VASCULAR DISEASES OF POSTERIOR EYE SEGMENT IN WOMEN AFTER PREECLAMPSIA, POSSIBILITIES OF PROGNOSIS

The purpose of study is to assess the clinical significance of microalbuminuria (MAU) in pregnant women with preeclampsia in formation of vascular eye pathology in long-term postpartum period.Material and methods. In retrospect, according to medical records, analysis of somatic condition of 114 women who had preeclampsia during pregnancy was carried out, and presence / absence of MAU during pregnancy were determined. MAU was detected in the 3rd trimester of pregnancy using test strips «Woerhringer Ingelheim» (Austria), considering the test to be positive with a value of 30 mg/day and more. The age of women at time of research was from 24 to 52 years, the period after suffering preeclampsia was 12.5 ± 6.5 years. Two groups were formed: the main – 35 women with initial MAU during pregnancy; the comparison – 79 women who had no MAU during pregnancy. The controls were 36 women with physiological pregnancy and delivery.Results and discussion. In period after delivery, vascular diseases of posterior eye segment occurred in 14 people in the main group (40 %) and 15 people in the comparison group (19 %). In the control group in this period, vascular pathology of posterior eye segment was formed in 2 women.Conclusion. Statistically significant increase of frequency of formation of vascular pathology of posterior eye segment in postpartum period was revealed in women, who had pregnancy complicated by preeclampsia and MAU in the 3rd trimester, which increased through 10 and more years after delivery. The initial presence of MAU during pregnancy can be the marker of increased risk of formation of vascular pathology of posterior eye segment at different periods of the postpartum period

Role of Gestational Hypertension and Preeclampsia as Risk Factors for Formation of Vascular Disorders of Retina in Remote Period after Delivery

Purpose. To study the correlation between pregnancy, complicated by preeclampsia and gestational hypertension (GH), and formation of retinal vascular and optic nerve disorders in the late postpartum period.Patients and methods. 231 women with different previous pregnancy variants of pathology. Exclusion criteria — presence of systemic endocrine, autoimmune, rheumatic pathology before pregnancy; bad habits. Four groups were formed. 1st main group: pregnancy with GH. 2nd main group: pregnancy with preeclampsia. 1st comparison group: pregnancy on the background of pre-existing hypertension, without proteinuria. 2nd comparison group: edema and/or proteinuria during pregnancy, without hypertension. The control group — physiological process of pregnancy. Period of ophthalmological examination after pregnancy is 6–12 years.Results. Development of various vascular and ischemic disorders of posterior eye segment occurred in 70 women (30.3 %). The periods of their formation after previous pregnancy varied from 3 to 11 years. Their frequency in the 1st and 2nd main groups was statistically significantly higher. The most common were retinal vein occlusion and post-thrombotic retinopathy. The negative outcomes of transferred GH and preeclampsia are no eliminated with delivery and can manifest next years and even decades after it.Conclusion. Нigh risk factors for development of vascular and ischemic disorders of posterior eye segment are transferred preeclampsia, especially with its early onset (20–24 weeks), or premature birth (26–28 weeks); pregnancy, complicated by GH. The risk of developing this eye pathology is highest in women aged 38–40 years and over

Creation of an algorithm for a prediction of vascular retinal pathology in women after suffered pre-eclampsia and an evaluation of its effeciency

Purpose. On the basis of previously identified potential predictors, to develop an algorithm for a prediction of vascular retinal pathology in women who have previously suffered from pregnancy complicated by preeclampsia.Material and methods. In the study there was conducted A dynamic observation of 83 women (133 eyes), who suffered from preeclampsia, ending in childbirth. The age of patients at the time of pregnancy ranged from 18 to 45 years, mean 31.9±6.1 years. In addition to the standard eye examination, all women underwent a study of chorioretinal hemodynamics and morphometric parameters of the macular area.Results. Based on previously revealed potential predictors, three variants of the algorithm for prediction of vascular retinal pathology in women after preeclampsia were developed. Algorithms can be considered reasonable and effective. They can be recommended to clinicians for the selection of women suffered from preeclampsia in the group with a risk of vascular retinal pathology development in long-term periods after childbirth.Conclusion. Three variants of the prognostic algorithm of risk for the formation of vascular retinal pathology in women after suffered preeclampsia have been developed, for periods up to 10 years. They differ from each other in various sets of predictors and are oriented, respectively, for the use in the following conditions: specialized ophthalmologic clinic, ophthalmology office of the out-patient clinic and obstetriciangynecologists