208 research outputs found

    Solid-state synthesis and characterization of ferromagnetic Mn5Ge3 nanoclusters in GeO/Mn thin films

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    Mn5Ge3 films are promising materials for spintronic applications due to their high spin polarization and a Curie temperature above room temperature. However, non-magnetic elements such as oxygen, carbon and nitrogen may unpredictably change the structural and magnetic properties of Mn5Ge3 films. Here, we use the solid-state reaction between Mn and GeO thin films to describe the synthesis and the structural and magnetic characterization of Mn5Ge3(Mn5Ge3Oy)-GeO2(GeOx) nanocomposite materials. Our results show that the synthesis of these nanocomposites starts at 180°С when the GeO decomposes into elemental germanium and oxygen and the resulting Ge atoms immediately migrate into the Mn layer to form ferromagnetic Mn5Ge3 nanoclusters. At the same time the oxygen atoms take part in the synthesis of GeOx and GeO2 oxides and also migrate into the Mn5Ge3 lattice to form Mn5Ge3Oy Nowotny nanoclusters. Magnetic analysis assumes the general nature of the Curie temperature increase in carbon-doped Mn5Ge3Cx and Mn5Ge3Oy films. Our findings prove that not only carbon, but oxygen may contribute to the increase of the saturation magnetization and Curie temperature of Mn5Ge3-based nanostructures

    Modern trends in diagnostics and prediction of results of anti-vascular endothelial growth factor therapy of pigment epithelial detachment in neovascular agerelated macular degeneration using deep machine learning method (literature review)

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    Detachment of the pigment epithelium is the separation of the basement membrane of the retinal pigment epithelium from the inner collagen layer of Bruch’s membrane, which occurs in 80 % of cases in patients with neovascular age-related macular degeneration. The outcome of anti-VEGF therapy for pigment epithelial detachment may be adherence of the pigment epithelium, the formation of pigment epithelium tear, or preservation of the detachment. The pigment epithelium tear of 3–4th degrees can lead to a sharp decrease in visual acuity.Most retrospective studies confi rm the absence of a proven correlation between anatomical and functional outcomes in the treatment of pigment epithelial detachment in cases of maintaining the integrity of the pigment epithelium monolayer, and therefore the main attention of researchers is focused on studying the morphological features of pigment epithelial detachment during therapy with angiogenesis inhibitors. Modern technologies of spectral optical coherence tomography make it possible to evaluate detailed quantitative parameters of pigment epithelium detachment, such as height, width, maximum linear diameter, area, volume and refl ectivity within the detachment.Groups of Russian and foreign authors identify various biomarkers recorded on optical coherence tomography images. Dynamic registration of such biomarkers expands the ability of clinicians to predict morphological changes in pigment epithelial detachment during anti-VEGF therapy, as well as to optimize treatment regimens to prevent complications in the form of pigment epithelium tear leading to a decrease in visual acuity.Modern methods of deep machine learning and the use of neural networks allow achieving higher accuracy in diff erentiating the types of retinal fluids and automating the quantitative determination of fl uid under the pigment epithelium. These technologies allow achieving a high level of compliance with manual expert assessment and increasing the accuracy and speed of predicting morphological results of treatment of pigment epithelium detachments

    Results of chalazion cryosurgery with an increased risk of complications

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    Background. At an appointment with an ophthalmologist, patients with pathological conditions of the eyelids are often dissatisfi ed with the effectiveness of the traditional surgical treatment.The aim: assessment of the functional state of the eye adnexa after cryodestruction of the chalazion with an increased risk of complications using modern cryosurgical equipment.Material and methods. Clinical studies were carried out in 254 patients (277 eyes) with chalazion, including a complicated course of the disease, with cryodestruction of the chalazion using an autonomous cryoapplicator made of porous-permeable titanium nickelide.Results. Cryosystems of the new generation, in comparison with the well-known industrial cryoapparatus, diff er in new properties. They can signifi cantly improve the quality of cryotherapy in surgery due to a clearer localization of cryotherapy and a high rate of heat removal from the surface of altered tissues without damaging the surrounding tissues. Depending on the size of the pathological formation, the duration of the exposure, the frequency of repetitions of the applications during the session, the regression of the chalazion occurred within 1–1.5 months with the preservation of the integrity of the intermarginal space and the functional state of the eyelid.Conclusion. Analysis of the data obtained indicates a high clinical and cosmetic effi ciency of cryosurgery of the eyelid chalazion using an autonomous cryoapplicator made of porous-permeable titanium nickelide

    Software ”IDA” for asteroid motion study

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    Прикладной программный комплекс "ИДА" позволяет осуществлять высокоточное прогнозирование движения астероидов и исследование особенностей их динамики, таких как сближения и резонансы (орбитальные и вековые) с планетами, хаотичность и предсказуемость движения и др.The software “IDA” is intended for high-precision prediction of asteroid motion and investigation of special features of their dynamics such as close approaches and resonances (mean motion and secular) with planets, chaotisity and predictability of motion and some others.Работа выполнена при финансовой поддержке РФФИ 15-02-02868а

    Arterial Hypertension and Severe COVID-19 in Hospitalized Patients: Data from a Cohort Study

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    Aim. To assess the association  of hypertension  with the severe forms and fatal outcomes of Coronavirus disease 2019 (COVID-19).Material and Methods. This retrospective  cohort study involved adult patients (≥18 years old),  admitted to the University  hospital №4 of Sechenov University (Moscow, Russia) between 08 April 2020 and 19 November 2020 with clinically diagnosed or laboratory-confirmed COVID-19. The cohort included 1637 patients. The primary outcome was all-cause in-hospital mortality. The secondary outcomes included intensive care unit admission (ICU) and invasive ventilation. Multiple logistic regression was performed to assess the independent association  between risk factors and endpoints.Results. A total of 1637 patients were included in the study. 51.80% (n=848) of the subjects were males. The median age was 59.0 (48.0; 70.0) years and 55.90% (n=915) had pre-existing diagnosis of hypertension. Patients with hypertension  had significantly more severe lung injury based on chest CT scan findings  as well as lower oxygen saturation  (SрO2). More of them were admitted to ICU  and  placed  on invasive  ventilation.  The hypertension  group  also  had  higher  mortality.  Age,  hypertension, glucose, C-reactive protein and decreased platelet count were independently associated with mortality, hypertension  having the strongest association (OR 1.827, 95% CI 1.174-2.846, p=0.008). Age,  hypertension, neutrophil count, platelet count, glucose, and CRP were independently associated  with ICU  admission, with hypertension  having  the strongest  association  (OR  1.595, 95% CI 1.178-2.158, p=0.002). Age, hypertension, glucose, CRP and decreased platelet count were independently associated with invasive ventilation, with hypertension having the strongest association  (OR  1.703, 95% CI 1.151-2.519, p=0.008).Based on the multiple logistic regression models, odds of death, ICU admission, and invasive ventilation were higher in the hypertension  group as compared  to the group without hypertension.Conclusion. Hypertension can be an independent predictor of severe COVID-19 and adverse outcomes, namely death, ICU admission, and invasive ventilation in hospitalized  patients
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