35 research outputs found
ПСИХОЕМОЦІОНАЛЬНИЙ СТАТУС І ЙОГО КОРЕКЦІЯ ПРИ ЗАГРОЗІ ПЕРЕРИВАННЯ ВАГІТНОСТІ
Обстежена група практично здорових не вагітних, вагітних і пацієнток з загрозою переривання (167 жінок). По клінічному опитуванні для виявлення неврозних станів (К.К.Яхин, В.М.Менделевич) знайдено, що у практично здорових не вагітних жінок по різних шкалах станів психоемоціонального здоров’я в цілому від 6,7 % (ШВН) до 33,3 % (ШИТР) жінок, під час фізіологічної вагітності - від 13,3 % (ШТ) до (27, 9 %) пацієнток. При загрозі переривання психоемоційний статус характеризується станом дезадаптації або гіперадаптації. Застосування ДЄНС в комплексній терапії дозволило знизити медикаментозну нагрузку і зберегти вагітність у всіх обстежених. В групі порівняння вагітнсть збережена у 93 % випадків за рахунок довготривалої гормональної терапії
Synthesis of High-Purity Silica Nanoparticles by Sol-Gel Method
Colloidal silica (silica sol) nanoparticles were synthesized by ammonia- and hydrochloric acid-catalyzed hydrolysis of tetraethoxysilane with subsequent condensation and polymerization. Silica particles with the size of 12‒160 nm were obtained at different temperatures and ratios of the initial reactants and studied by means of TEM, AFM, IR spectroscopy and zeta-potential measurements. The reaction conditions providing the minimum particle size in the final product of the most complete hydrolysis were determined. At pH above 8.5, an increase in the SiO2 content of the sol to 23 wt.% did not change the particle size. At a low (~ 1.8 wt.%) SiO2 content of the sol, a wide variation in pH also did not exert a significant effect on the particle size. Stability of the silica sols synthesized in an alkaline medium was enhanced by the replacement of alcohol with water during evaporation at pH 8.5‒9.5. The possibility to produce silica sols with the required characteristics (particle size, pH, stability, purity, and SiO2 content in an aqueous or alcohol medium) makes them applicable in various industries
Low temperature electrical transport in microwave plasma fabricated free-standing graphene and N-graphene sheets
Funding Information: This work was performed under the framework of the PEGASUS (Plasma Enabled and Graphene Allowed Synthesis of Unique nano-Structures) project, funded by the European Union’s Horizon research and innovation program under grant agreement No 766894. Work partially funded by Portuguese FCT - Fundação para a Ciência e a Tecnologia, through EAGER project (PTDC/NAN-MAT/30565/2017) and under projects UIDB/50010/2020 and UIDP/50010/2020. The authors would like to thank S. Russev for the SEM images. M A, E V, K K and Zh K thank the European Regional Development Fund within the Operational Programme ‘Science and Education for Smart Growth 2014–2020’ under the Project CoE ‘National center of mechatronics and clean technologies ‘BG05M2OP001-1.001-0008’. Publisher Copyright: © 2023 The Author(s). Published by IOP Publishing Ltd.In this paper, the electrical transport in free-standing graphene and N-graphene sheets fabricated by a microwave plasma-based method is addressed. Temperature-dependent resistivity/conductivity measurements are performed on the graphene/N-graphene sheets compressed in pellets. Different measurement configurations reveal directional dependence of current flow—the room-temperature conductivity longitudinal to the pellet’s plane is an order of magnitude higher than the transversal one, due to the preferential orientation of graphene sheets in the pellets. SEM imaging confirms that the graphene sheets are mostly oriented parallel to the pellet’s plane and stacked in agglomerates. The high longitudinal electrical conductivity with values on the order of 103 S/m should be noted. Further, the current flow mechanism revealed from resistivity-temperature dependences from 300K down to 10K shows non-metallic behavior manifested with an increasing resistivity with decreasing the temperature d ρ / d T < 0 usually observed for insulating or localized systems. The observed charge transport shows variable range hopping at lower temperatures and thermally activated behaviour at higher temperatures. This allows us to attribute the charge transport mechanism to a partially disordered system in which single graphene sheets are placed predominantly parallel to each other and stacked together.publishersversionpublishe
Prospects for microwave plasma synthesized N-graphene in secondary electron emission mitigation applications
PTDC/NAN-MAT/30565/2017
D01-284/2019 (INFRAMAT)
IBB BASE 2020-2023
UID/FIS/00068/2019.The ability to change the secondary electron emission properties of nitrogen-doped graphene (N-graphene) has been demonstrated. To this end, a novel microwave plasma-enabled scalable route for continuous and controllable fabrication of free-standing N-graphene sheets was developed. High-quality N-graphene with prescribed structural qualities was produced at a rate of 0.5 mg/min by tailoring the high energy density plasma environment. Up to 8% of nitrogen doping levels were achieved while keeping the oxygen content at residual amounts ( 1%). The synthesis is accomplished via a single step, at atmospheric conditions, using ethanol/methane and ammonia/methylamine as carbon and nitrogen precursors. The type and level of doping is affected by the position where the N-precursor is injected in the plasma environment and by the type of precursors used. Importantly, N atoms incorporated predominantly in pyridinic/pyrrolic functional groups alter the performance of the collective electronic oscillations, i.e. plasmons, of graphene. For the first time it has been demonstrated that the synergistic effect between the electronic structure changes and the reduction of graphene $-plasmons caused by N doping, along with the peculiar “crumpled” morphology, leads to sub-unitary (textless 1) secondary electron yields. N-graphene can be considered as a prospective low secondary electron emission and plasmonic material.publishersversionpublishe
N2-H2 capacitively coupled radio-frequency discharges at low pressure. Part I. Experimental results: Effect of the H2 amount on electrons, positive ions and ammonia formation
The mixing of N2 with H2 leads to very different plasmas from pure N2 and H2 plasma discharges. Numerous issues are therefore raised involving the processes leading to ammonia (NH3) formation. The aim of this work is to better characterize capacitively-coupled radiofrequency plasma discharges in N2 with few percents of H2 (up to 5%), at low pressure (0.3-1 mbar) and low coupled power (3-13 W). Both experimental measurements and numerical simulations are performed. For clarity, we separated the results in two complementary parts. The actual one (first part), presents the details on the experimental measurements, while the second focuses on the simulation, a hybrid model combining a 2D fluid module and a 0D kinetic module. Electron density is measured by a resonant cavity method. It varies from 0.4 to 5 109 cm-3, corresponding to ionization degrees from 2 10-8 to 4 10-7. Ammonia density is quantified by combining IR absorption and mass spectrometry. It increases linearly with the amount of H2 (up to 3 1013 cm-3 at 5% H2). On the contrary, it is constant with pressure, which suggests the dominance of surface processes on the formation of ammonia. Positive ions are measured by mass spectrometry. Nitrogen-bearing ions are hydrogenated by the injection of H2, N2H+ being the major ion as soon as the amount of H2 is >1%. The increase of pressure leads to an increase of secondary ions formed by ion/radical-neutral collisions (ex: N2H+, NH4 +, H3 +), while an increase of the coupled power favours ions formed by direct ionization (ex: N2 +, NH3 +, H2 +).N. Carrasco acknowledges the financial support of the European Research Council (ERC Starting Grant
PRIMCHEM, Grant agreement no. 636829).
A. Chatain acknowledges ENS Paris-Saclay Doctoral Program. A. Chatain is grateful to Gilles Cartry and
Thomas Gautier for fruitful discussions on the MS calibration.
L.L. Alves acknowledges the financial support of the Portuguese Foundation for Science and Technology (FCT) through the project UID/FIS/50010/2019.
L. Marques and M. J. Redondo acknowledge the financial support of the Portuguese Foundation for Science
and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2019
17-OHPC to Prevent Recurrent Preterm Birth in Singleton Gestations (PROLONG Study): A Multicenter, International, Randomized Double-Blind Trial
Background âwomen with a history of spontaneous preterm birth (SPTB) are at a significantly increased risk for recurrent preterm birth (PTB). To date, only one large U.S. clinical trial comparing 17-OHPC (17-α-hydroxyprogesterone caproate or 17P) to placebo has been published, and this trial was stopped early due to a large treatment benefit. Objective âThis study aimed to assess whether 17-OHPC decreases recurrent PTB and neonatal morbidity in women with a prior SPTB in a singleton gestation. Study Design âThis was a double-blind, placebo-controlled international trial involving women with a previous singleton SPTB (clinicaltrials.gov: NCT 01004029). Women were enrolled at 93 clinical centers (41 in the United States and 52 outside the United States) between 16 0/7 to 20 6/7 weeks in a 2:1 ratio, to receive either weekly intramuscular (IM) injections of 250 mg of 17-OHPC or an inert oil placebo; treatment was continued until delivery or 36 weeks. Co-primary outcomes were PTB < 35 weeks and a neonatal morbidity composite index. The composite included any of the following: Neonatal death, grade 3 or 4 intraventricular hemorrhage, respiratory distress syndrome, bronchopulmonary dysplasia, necrotizing enterocolitis, or proven sepsis. A planned sample size of 1,707 patients was estimated to provide 98% power to detect a 30% reduction in PTB < 35 weeks (30% to 21%) and 90% power to detect a 35% reduction in neonatal composite index (17%-11%) using a two-sided type-I error of 5%. Finally, this sample size would also provide 82.8% power to rule out a doubling in the risk of fetal/early infant death assuming a 4% fetal/early infant death rate. Analysis was performed according to the intention-to-treat principle. Results âaseline characteristics between the 1,130 women who received 17-OHPC and 578 women who received placebo were similar. Overall, 87% of enrolled women were Caucasian, 12% had >1 prior SPTB, 7% smoked cigarettes, and 89% were married/lived with partner. Prior to receiving study drug, 73% women had a transvaginal cervical length measurement performed and <2% had cervical shortening <25 mm. There were no significant differences in the frequency of PTB < 35 weeks (17-OHPC 11.0% vs. placebo 11.5%; relative risk = 0.95 [95% confidence interval (CI): 0.71-1.26]) or neonatal morbidity index (17-OHPC 5.6% vs. placebo 5.0%; relative risk = 1.12 [95% CI: 0.68-1.61]). There were also no differences in frequency of fetal/early infant death (17-OHPC 1.7% vs. placebo 1.9%; relative risk = 0.87 [95% CI: 0.4-1.81]. Maternal outcomes were also similar. In the subgroup of women enrolled in the United States (n = 391; 23% of all patients), although the rate of PTB < 35 weeks was higher than the overall study population, there were no statistically significant differences between groups (15.6% vs. 17.6%; relative risk = 0.88 [95% CI: 0.55, 1.40]. Conclusion âin this study population, 17-OHPC did not decrease recurrent PTB and was not associated with increased fetal/early infant death
State of Social Activity of the Buryat Population at the Present Stage
Участие населения в жизни общества, в реализации реформ, инициированных руководством страны или регионов, всегда было важно для России. С развитием гражданского общества значимым становится увеличение влияния граждан на принимаемые властью решения. Вариантами проявления социальной активности могут выступать разнообразные ее формы: от участия в выборах, политических, экологических, социальных акциях до создания ТОС. Видимыми становятся и нестандартные, нетрадиционные формы социальной активности, связанные с желанием активистов заявить о своей инициативе, а также о собственном видении вариантов решения проблем. Очевидна и поляризация взглядов общества на проявление активности и ее реализацию. В статье авторы по результатам локального исследования оценивают гражданскую активность населения Республики Бурятия.The participation of the population in the life of society, in the implementation of reforms initiated by the leadership of the country or regions, always were very important for Russia. Strengthening the influence of citizens on decisions made by the authorities becomes more important with the development of civil society. The variants of the manifestation of social activity can be the various forms from participation in voting, political, environmental, social actions to the creation of territorial self-government bodies. Unconventional and irregular forms of social activity are also becoming visible, associated with the desire of activists to declare their initiative, as well as their own vision of options for solving problems. The polarization of society's views on the manifestation of social activity and its implementation is obvious. In the article, the authors, based on the results of a local study, evaluate the social activity of the population of the Republic of Buryatia
On the plasma-based growth of 'flowing' graphene sheets at atmospheric pressure conditions
The article of record as published may be found at http://dx.doi.org/10.1088/0963-0252/25/1/015013A theoretical and experimental study on atmospheric pressure microwave plasma-based
assembly of free standing graphene sheets is presented. The synthesis method is based on
introducing a carbon-containing precursor (C₂H₅OH) through a microwave (2.45 GHz) argon
plasma environment, where decomposition of ethanol molecules takes place and carbon
atoms and molecules are created and then converted into solid carbon nuclei in the ‘colder’
nucleation zones. A theoretical model previously developed has been further updated and
refined to map the particle and thermal fluxes in the plasma reactor. Considering the nucleation
process as a delicate interplay between thermodynamic and kinetic factors, the model is based
on a set of non-linear differential equations describing plasma thermodynamics and chemical
kinetics. The model predictions were validated by experimental results. Optical emission
spectroscopy was applied to detect the plasma emission related to carbon species from the
‘hot’ plasma zone. Raman spectroscopy, scanning electron microscopy (SEM), and x-ray
photoelectron spectroscopy (XPS) techniques have been applied to analyze the synthesized
nanostructures. The microstructural features of the solid carbon nuclei collected from the
colder zones of plasma reactor vary according to their location. A part of the solid carbon
was deposited on the discharge tube wall. The solid assembled from the main stream, which
was gradually withdrawn from the hot plasma region in the outlet plasma stream directed to
a filter, was composed by ‘flowing’ graphene sheets. The influence of additional hydrogen,
Ar flow rate and microwave power on the concentration of obtained stable species and
carbon−dicarbon was evaluated. The ratio of sp³/sp² carbons in graphene sheets is presented.
A correlation between changes in C₂ and C number densities and sp³/sp² ratio was found.Portuguese FCT--Fundação para a Ciência e a Tecnologia, under Project UID/FIS/50010/2013, Project INCENTIVO/FIS/LA0010/2014, and grant SFRH/BD/52413/2013 (PD-F APPLAuSE)
Malignant tumors of the digestive system during pregnancy: problems of timely diagnosis
Currently, the age of primiparous women is increasing, but the risk of cancer, which is sometimes found during gestation, is also increasing. This article discusses the problems of diagnosis and treatment of cancer during pregnancy, which occurs under the guise of gestational complications. Two cases of malignant neoplasms first discovered during pregnancy are described. The first observation illustrates cholangiocarcinoma in a 37-year-old multiparous, and the second is a case of colorectal cancer in a 40-year-old primiparous. The timely identification of such women is an important challenge of the outpatient, which in the future can help maintain the quality of life of the mother and child
Low total electron yield graphene coatings produced by electrophoretic deposition
Stainless steel and copper technical substrates have been coated by free standing graphene using electrophoretic deposition technique, with the final goal to obtain chemically inert low secondary electron emission surfaces. This class of materials is of utmost interest in future accelerators in order to increase further the flux of accelerated charged particles in the beam. The measured maximum total electron yield of pristine graphene, which has been previously characterized by electron microscopies and X-ray photoelectron spectroscopy, appears to be about 1.0. The deposition parameters have been optimized in order to obtain surfaces with lowest total electron yield, but also composition and morphology close to that of pristine graphene. When applying these optimized deposition parameters graphene coatings on two substrates, i.e. stainless steel and copper, the maximum total electron yield of about 1.04 was obtained. The composition of coatings and the relative amounts of sp2 bonds are slightly worse than those of the pristine graphene, while the surface morphology appears to be the same. Annealing at 150 °C for 64 h in high vacuum, showed that vacuum baking did not affect considerably the electron emission properties of the coatings. © 2019 Elsevier B.V