113 research outputs found

    Large Magnetic Entropy Change in GdRuSi Optimal for Magnetocaloric Liquefaction of Nitrogen

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    The search for new magnetocaloric materials for application in magnetic refrigerants is highly motivated by high efficiency, reliability, and environmental safety. The values of the magnetocaloric effect MCE and the refrigerant capacity RC for the equiatomic GdRuSi compound were determined to be MCE = 10.7 and 4.94 J/kgK and RC = 336 and 92 J/kg with a change in the field of 0–50 and 0–17 kOe, respectively. These high values of MCE and RC for GdRuSi appear in the region of nitrogen liquefaction temperature of 77.4 K, due to which the compound can be useful in practice. The densities of states and magnetic moments of GdRuSi were calculated theoretically, taking into account strong electron correlations in the 4f Gd shell. The total magnetic moment of GdRuSi was found to be composed of the Gd moment only with the value calculated in very good agreement with the experimental one. © 2023 by the authors.Ministry of Education and Science of the Russian Federation, Minobrnauka: 122021000034-9, 122021000039-4; Russian Science Foundation, RSF: 18-72-10098The results of Section 1, Section 2, Section 3.1 and Section 3.2 (magnetic properties and electronic structure calculations) were obtained within the grant of the Russian Science Foundation No. 18-72-10098, https://rscf.ru/en/project/18-72-10098/ (accessed on 29 December 2022). The results of Section 3.3 were obtained within the state assignment of Ministry of Science and Higher Education of the Russian Federation (themes “Magnet” No. 122021000034-9 and “Electron” No. 122021000039-4)

    Факторы, влияющие на общую выживаемость при протоковой аденокарциноме головки поджелудочной железы. Опыт одного центра

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    Purpose. To identify major factors affecting the overall survival (OS). To select the cohort of patients with the best prognosis.Materials and methods. A retrospective analysis included data of 268 patients, 128 men and 140 women, with median age of 59±10,53 (30 to 83) years. For multivariate analysis of survival, patients were selected who underwent pancreaticoduodenectomy (PD) for ductal adenocarcinoma of the pancreatic head.Results. Our study demonstrated that histologically verified vascular invasion (detected only in 30 % of patients who underwent PD with resection of the major vessels) statistically significantly affected the OS. The increased CA19-9 level over 500 U / L (detected in 32,3 % of cases) is the factor that significantly worsens the OS. Patients with high grade adenocarcinoma have significantly better survival rates compared with patients who have moderately or poorly differentiated adenocarcinoma (p = 0.014; median 26 months, 95 % CI 4.4–47.6 versus median 17 months, 95 % CI 15–19, an median: 13 months, 95 % CI 5–21, respectively). Also, the use of adjuvant chemotherapy has a positive effect on long-term outcomes (p = 0.0001; median 26 months, 95 % CI 21.7–30.3 versus median 13 months, 95 % CI 11.3–14.7).Conclusion. A well-differentiated tumor and the use of adjuvant chemotherapy significantly increase the OS of patients. Poorly differentiated tumor, CA19-9 level over 500 U / mL and the histologically confirmed vascular invasion significantly worsen the prognosis of these patients.Цель. Определить ведущие факторы, оказывающие влияние на общую выживаемость (ОВ). Выделить когорту пациентов с наилучшим прогнозом заболевания.Материалы и методы. В ретроспективный анализ были включены 268 пациентов, 128 мужчин и 140 женщин средним возрастом 59±10,53 (от 30 до 83) лет. Для многофакторного анализа и анализа выживаемости отобраны больные, которым была выполнена гастропанкреатодуоденальная резекция (ГПДР) по поводу протоковой аденокарциномы головки поджелудочной железы.Результаты. В нашем исследовании показано, что на ОВ статистически значимо влияет морфологически подтвержденная инвазия опухоли в сосудистую стенку, которая выявилась лишь у 30% больных, перенесших ГПДР с резекцией магистральных сосудов. Уровень онкомаркера CА19-9 более 500 ЕД/л был выявлен в 32,3% случаях и является фактором, достоверно ухудшающим ОВ. Пациенты с высокодифференцированной аденокарциномой имеют достоверно лучшие показатели выживаемости по сравнению с больными, у которых выявлена умеренно-или низкодифференцированная аденокарцинома (р =0,014; медиана 26 месяцев, 95% ДИ 4,4–47,6 против медианы 17 месяцев, 95% ДИ 15–19, и медианы 13 месяцев, 95% ДИ 5–21). Кроме того, положительное влияние на отдаленные результаты оказывает применение адъювантной химиотерапии (ХТ) (р =0,0001; медиана 26 месяцев, 95% ДИ 21,7–30,3 против медианы 13 месяцев, 95% ДИ 11,3–14,7).Заключение. Высокая степень дифференцировки опухоли и применение ХТ в адъювантном режиме достоверно увеличивают ОВ пациентов. Низкая степень дифференцировки опухоли, уровень СА19-9 более 500 Ед/мл и гистологически верифицированная инвазия опухоли в стенку магистральных сосудов достоверно ухудшают прогноз этих пациентов

    Transcatheter mitral valve edge-to-edge repair in patients with severe mitral regurgitation: data from the MitraClip Russia Trial

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    Aim. To study the immediate and short-term outcomes of transcatheter mitral valve edge-to-edge repair with the MitraClip NT in patients with severe mitral regurgitation as part of the MitraClip Russia prospective single-center study.Material and methods. The study included 16 patients (men, 10; women, 6) with mean age of 70,1±2,1 years (mean Euroscore II, 6,90±5,56%; STS, 6,33±3,94%). Immediate technical success was defined as successful access, delivery, and removal of the device, and adequate placing the clip(s) to reduce the mitral regurgitation to grade 2 or below without the need for device- or procedure-related reintervention.Results. Immediate technical success was achieved in all patients. The average number of implanted clips per 1 patient was 1,7. In 1 patient (6,3%), a clip was attached to one mitral leaflet, which required an non-scheduled implantation of a second clip. In hospital mortality was 6,3%: a 92-year-old patient on the 3rd day after the operation had a sudden cardiac arrest followed by coma, hemispheric ischemic stroke and death on the 6th day. An autopsy revealed an iatrogenic atrial septal defect. Echocardiography performed on the 10th and 30th day after surgery showed a decrease in mitral regurgitation grade in 15 patients, while grade 3 residual mitral regurgitation did not reveal in any patient.Conclusion. Transcatheter mitral valve edge-to-edge repair with the MitraClip is a minimally invasive method for treating severe symptomatic mitral regurgitation (degenerative and functional). The results demonstrate high immediate efficacy and an acceptable safety profile in high surgical risk patients. Based on the analysis of death causes, the authors conclude that it is necessary to include initial pulmonary hypertension above 75 mm Hg as a relative contraindication to this procedure. The study limitations are the small sample size and short follow-up period

    Hysteresis of the Contact Angle of a Meniscus Inside a Capillary with Smooth, Homogeneous Solid Walls

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    This paper was accepted for publication in the journal Langmuir: the ACS journal of surfaces and colloids and the definitive published version is available at http://dx.doi.org/10.1021/acs.langmuir.6b00721.A theory of contact angle hysteresis of a meniscus inside thin capillaries with smooth, homogeneous solid walls is developed in terms of surface forces (disjoining/ conjoining pressure isotherm) using a quasi-equilibrium approach. The disjoining /conjoining pressure isotherm includes electrostatic, intermolecular, and structural components. The values of the static receding θr, advancing θa , and equilibrium θe contact angles in thin capillaries were calculated on the basis of the shape of the disjoining/conjoining pressure isotherm. It was shown that both advancing and receding contact angles depend on the capillary radius. The suggested mechanism of the contact angle hysteresis has a direct experimental confirmation: the process of receding is accompanied by the formation of thick β-films on the capillary walls. The effect of the transition from partial to complete wetting in thin capillaries is predicted and analyzed. This effect takes place in very thin capillaries, when the receding contact angle decreases to zero

    Hysteresis of Contact Angle of Sessile Droplets on Smooth Homogeneous Solid Substrates via Disjoining/Conjoining Pressure

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    This document is the Accepted Manuscript version of a Published Work that appeared in final form in Langmuir copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/acs.langmuir.5b01075A theory of contact angle hysteresis of liquid droplets on smooth, homogeneous solid substrates is developed in terms of the shape of the disjoining/conjoining pressure isotherm and quasi-equilibrium phenomena. It is shown that all contact angles, θ, in the range θr < θ < θa, which are different from the unique equilibrium contact angle θ ≠ θe, correspond to the state of slow “microscopic” advancing or receding motion of the liquid if θe < θ < θa or θr < θ < θe, respectively. This “microscopic” motion almost abruptly becomes fast “macroscopic” advancing or receding motion after the contact angle reaches the critical values θa or θr, correspondingly. The values of the static receding, θr, and static advancing, θa, contact angles in cylindrical capillaries were calculated earlier, based on the shape of disjoining/conjoining pressure isotherm. It is shown now that (i) both advancing and receding contact angles of a droplet on a on smooth, homogeneous solid substrate can be calculated based on shape of disjoining/conjoining pressure isotherm, and (ii) both advancing and receding contact angles depend on the drop volume and are not unique characteristics of the liquid–solid system. The latter is different from advancing/receding contact angles in thin capillaries. It is shown also that the receding contact angle is much closer to the equilibrium contact angle than the advancing contact angle. The latter conclusion is unexpected and is in a contradiction with the commonly accepted view that the advancing contact angle can be taken as the first approximation for the equilibrium contact angle. The dependency of hysteresis contact angles on the drop volume has a direct experimental confirmation

    Первичная меланома пищевода. Обзор литературы, клиническое наблюдение

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    Primary malignant melanoma of the esophagus is a rare disease with an aggressive course and poor prognosis. This article presents a review of the world literature on this specific disease, including incidence statistics, modern principles of diagnosis and treatment, as well as a clinical case of a patient with resectable esophageal melanoma.Первичная меланома пищевода является редким заболеванием, обладающим агрессивным течением и неблагоприятным прогнозом. В данной статье представлен обзор мировой литературы по данной нозологической форме заболевания, включающий в себя статистику заболеваемости, а также современные принципы диагностики и лечения пациентов с данной патологией и клиническое наблюдение лечения пациента с резектабельной формой заболевания

    Влияние диборнола-ГЭК на электрофизиологические параметры в период восстановления кровотока в миокарде кролика

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    Objective. Dibornol-HES, a water-soluble drug based on the derivative of 2,6-diisobornyl-4-methylphenol Dibornol conjugated with hydroxyethyl starch, can reduce the occurrence and severity of arrhythmias by preventive intravenous administration, but it is unknown whether the drug could reduce the myocardial arrhythmogenicity once ischemia has developed at the developed ischemia.Materials and methods. In the model of acute ischemia / reperfusion of the rabbit heart, the effect of Dibornol-HEC (80 mg/kg body weight of the animal) on the electrophysiological indices characterizing myocardial arrhythmogenicity (global and border dispersion of repolarization) was studied during the restoration of blood flow. In the model of acute ischemia / reperfusion with 64 unipolar epicardial leads, the activation-recovery intervals were measured and global and border dispersion of repolarization in the native rabbits (control group, n = 9) and in the rabbits treated by Dibornol-HES (on the 25th minute of occlusion, the experimental group, n = 6).Results. The introduction of Dibornol-HES did not lead to a change in the electrocardiographic parameters of rabbits. By the 30th minute of the coronary occlusion on the ECG in the animals of the control and the experimental groups, the intervals RR, QT, QTc were shortened (p &lt; 0.05). In the animals of both groups by the 30th minute of coronary occlusion, the global dispersion of repolarization increased (p &lt; 0.05), the boundary dispersion of repolarization also increased (p &lt; 0.05), due to the decrease in the duration of the activation-recovery intervals in the ischemic zone (p &lt; 0.05). During the 30-minute reperfusion the magnitude of the global dispersion of repolarization did not change in animals of the both groups, and the magnitude of the border dispersion of repolarization in the control rabbits decreased (p &lt; 0.05), while in the rabbits treated by Dibornol-HES the border dispersion of repolarization did not changed.Conclusion. In rabbits of the experimental group, the values of the global and border dispersions of repolarization did not differ from those of the animals in the control group. Therefore, the administration to Dibornol-HES just prior to reperfusion does not lead to the decrease in the dispersion of repolarization increased as a result of acute ischemic myocardial damage.Введение. Диборнол-ГЭК, водорастворимый лекарственный препарат на основе производного 2,6-диизоборнил-4-метилфенола диборнола, конъюгированного гидроксиэтилкрахмалом, способен снижать возникновение и тяжесть аритмий при превентивном внутривенном введении. Однако о данных, способен ли препарат снижать аритмогенность миокарда при его введении в момент уже развившейся ишемии, не известно.Цель работы – исследование влияния препарата диборнола-ГЭК на электрофизиологические показатели сердца кролика в период восстановления кровотока в миокарде.Материалы и методы. В модели острой ишемии (реперфузии) сердца кролика изучено действие диборнола-ГЭК (80 мг/кг массы тела животного) на электрофизиологические показатели, характеризующие аритмогенность миокарда (глобальная и пограничная дисперсии реполяризации, длительность интервала «активация–восстановление») в период восстановления кровотока. У нативных кроликов (контрольная группа, n = 9) и кроликов, получавших внутривенно диборнол-ГЭК (на 25-й мин окклюзии, опытная группа, n = 6), в модели острой ишемии (реперфузии) в 64 униполярных эпикардиальных отведениях измерены интервалы «активация – восстановление», величина глобальной и пограничной дисперсии.Результаты. Введение диборнола-ГЭК не приводило к изменению электрокардиографических параметров кроликов. К 30-й мин коронарной окклюзии на электрокардиограмме у животных контрольной и опытной групп выявлено укорочение интервалов RR, QT, QTc (p &lt; 0,05). У животных обеих групп к 30-й мин ишемии глобальная дисперсия реполяризации увеличилась (p &lt; 0,05), пограничная дисперсия реполяризации также увеличилась (p &lt; 0,05) за счет уменьшения длительности интервалов «активация – восстановление» в ишемизированной зоне (p &lt; 0,05). В период 30-минутной реперфузии величина глобальной дисперсии реполяризации не изменялась у животных обеих групп, а величина пограничной дисперсии реполяризации у контрольных кроликов уменьшилась (p &lt; 0,05), в то время как у кроликов, которым вводили диборнол-ГЭК, нет.Заключение. Значения глобальных и пограничных дисперсий реполяризации у кроликов экспериментальной группы не отличались от значений животных в контрольной группе. Поэтому введение диборнола-ГЭК непосредственно перед реперфузией не приводит к уменьшению дисперсии реполяризации, увеличенной в результате острого ишемического повреждения миокарда

    Overexpression of a Common Wheat Gene TaSnRK2.8 Enhances Tolerance to Drought, Salt and Low Temperature in Arabidopsis

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    Drought, salinity and low temperatures are major factors limiting crop productivity and quality. Sucrose non-fermenting1-related protein kinase 2 (SnRK2) plays a key role in abiotic stress signaling in plants. In this study, TaSnRK2.8, a SnRK2 member in wheat, was cloned and its functions under multi-stress conditions were characterized. Subcellular localization showed the presence of TaSnRK2.8 in the cell membrane, cytoplasm and nucleus. Expression pattern analyses in wheat revealed that TaSnRK2.8 was involved in response to PEG, NaCl and cold stresses, and possibly participates in ABA-dependent signal transduction pathways. To investigate its role under various environmental stresses, TaSnRK2.8 was transferred to Arabidopsis under control of the CaMV-35S promoter. Overexpression of TaSnRK2.8 resulted in enhanced tolerance to drought, salt and cold stresses, further confirmed by longer primary roots and various physiological characteristics, including higher relative water content, strengthened cell membrane stability, significantly lower osmotic potential, more chlorophyll content, and enhanced PSII activity. Meanwhile, TaSnRK2.8 plants had significantly lower total soluble sugar levels under normal growing conditions, suggesting that TaSnRK2.8 might be involved in carbohydrate metabolism. Moreover, the transcript levels of ABA biosynthesis (ABA1, ABA2), ABA signaling (ABI3, ABI4, ABI5), stress-responsive genes, including two ABA-dependent genes (RD20A, RD29B) and three ABA-independent genes (CBF1, CBF2, CBF3), were generally higher in TaSnRK2.8 plants than in WT/GFP controls under normal/stress conditions. Our results suggest that TaSnRK2.8 may act as a regulatory factor involved in a multiple stress response pathways
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