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

Synthesis of Nanoscale TiO2 and Study of the Effect of Their Crystal Structure on Single Cell Response

To study the effect of nanoscale titanium dioxide (TiO2) on cell responses, we synthesized four modifications of the TiO2 (amorphous, anatase, brookite, and rutile) capable of keeping their physicochemical characteristics in a cell culture medium. The modifications of nanoscale TiO2 were obtained by hydrolysis of TiCl4 and Ti(i-OC3H7)4 (TIP) upon variation of the synthesis conditions; their textural, morphological, structural, and dispersion characteristics were examined by a set of physicochemical methods: XRD, BET, SAXS, DLS, AFM, SEM, and HR-TEM. The effect of synthesis conditions (nature of precursor, pH, temperature, and addition of a complexing agent) on the structural-dispersion properties of TiO2 nanoparticles was studied. The hydrolysis methods providing the preparation of amorphous, anatase, brookite, and rutile modifications of TiO2 nanoparticles 3–5 nm in size were selected. Examination of different forms of TiO2 nanoparticles interaction with MDCK cells by transmission electron microscopy of ultrathin sections revealed different cell responses after treatment with different crystalline modifications and amorphous form of TiO2. The obtained results allowed us to conclude that direct contact of the nanoparticles with cell plasma membrane is the primary and critical step of their interaction and defines a subsequent response of the cell

The dependence of cylindrical resonator natural frequencies on the fluid density

The article examines the dependence of cylindrical resonator natural frequencies (sensitive element) on the density (mass) of different fluids flowing through it. The cylindrical resonators are being widely applied in automatic control systems of technological processes as oscillating transducer density meter. The article presents the experimental results that prove the dependence of natural frequencies and vibration amplitude on the fluid density

Investigation of the Sorption Properties of Ore Materials for the Removal of Sulfur Dioxide from Exhaust Flue Gases of Power Plants

The prospects of using a natural material – ferromanganese nodules (FMN) from the Gulf of Finland – as the SO2 adsorbent are discussed. The starting material was studied as pellets and powder using X-ray fluorescence spectroscopy, XRD, BET, and mechanical strength analysis; dependences of physicochemical parameters of the material on heat treatment at 100-1000 ºC were found. FMN samples were tested in the process of SO2 sorption. The sorptive capacity of FMN samples for SO2 was found to increase with humidity of adsorbents; FMN samples with a humidity above 40% were shown to be promising for the removal of sulfur dioxide from gase

Антибиотикорезистентность уропатогенов у пациентов с нефролитиазом на фоне сопутствующей ишемической болезни сердца

Objective: to identify the main causative agents of chronic calculous pyelonephritis and determine their antibiotic resistance in patients with nephrolithiasis combined with coronary heart disease (CHD).Material and methods. A retrospective case-control study included 181 patients aged 57 to 82 years old who were treated at the urological center of branch no. 1 of Burdenko Main Military Clinical Hospital in 2014–2019. All patients long-term suffered from urolithiasis complicated by chronic calculus pyelonephritis in combination with CHD. Clinically significant results of bacteriological urine examinations (CFU≥103) were analyzed. The midstream urine specimen cultivation was performed sectorally on Endo agar. The minimum suppressive concentration of the test antibacterial preparations for each of the detected microorganisms was determined by dilution on a dense Müller–Hinton agar culture medium (BBL, USA). The results were processed using the Shapiro–Wilk, Kolmogorov–Smirnov, and χ2 Pirson criteria. The values of p≤0,05 were considered as statistically significant.Results. Specimen culturing revealed Escherichia coli – 24.8%, Klebsiella pneumoniae – 18.3%, Pseudomanas aeruginosa – 11%. Staphylococcus spp., and Enterococcus spp. were most important among gram-positive pathogens (total 26.6% of cases). The sensitivity of the detected infectious agents to basic antibacterial drugs turned out to be sharply reduced. It is noteworthy that 65% of P. aeruginosa strains were sensitive to meropenem.Conclusion. In patients with recurrent urolithiasis combined with CHD, the proportion of gram-positive coccas was increased on the background of calculous pyelonephritis with a simultaneous decrease in the proportion of poly-resistant gram-negative infectious agents (nosocomial strains of E. coli and K. pneumoniae).Цель: выявить основных возбудителей хронического калькулезного пиелонефрита и определить их антибиотикорезистентность у пациентов с нефролитиазом, сочетающимся с ишемической болезнью сердца (ИБС).Материал и методы. Проведено ретроспективное эпидемиологическое исследование по типу «случай–контроль», в которое вошел 181 пациент в возрасте от 57 до 82 лет, пролеченный в урологическом центре филиала № 1 Главного военного клинического госпиталя им. академика Н.Н. Бурденко в 2014–2019 гг. Все больные длительно страдали мочекаменной болезнью (МКБ), осложненной хроническим калькулезным пиелонефритом, в сочетании с ИБС. Изучены клинически значимые результаты бактериологических анализов мочи (КОЕ≥103). Посев средней порции мочи выполняли секторным методом на агаре Эндо. Минимальную подавляющую концентрацию исследуемых антибактериальных препаратов для каждого из выявленных микроорганизмов определяли методом разведения на плотной питательной среде агара Мюллера–Хинтон (BBL, США). При статистической обработке результатов использовали критерии Шапиро–Уилка, Колмогорова–Смирнова и χ2 Пирсона. Статистически значимыми считали значения р≤0,05.Результаты. При посеве у пациентов выявлены: Escherichia coli – в 24,8% случаев, Klebsiella pneumoniae – в 18,3%, Pseudomanas aeruginosa – в 11%. Среди грамположительных возбудителей наибольшее значение имели Staphylococcus spp. и Enterococcus spp. (суммарно 26,6% случаев). Чувствительность обнаруженных инфекционных агентов к основным антибактериальным препаратам оказалась резко сниженной. Обращает на себя внимание тот факт, что к меропенему чувствительными были 65% штаммов P. aeruginosa.Заключение. У пациентов с рецидивирующей МКБ в сочетании с ИБС на фоне калькулезного пиелонефрита увеличена доля грамположительных кокков с одновременным снижением доли полирезистентных грамотрицательных инфекционных агентов (нозокомиальные штаммы E. coli и K. pneumoniae)

Peripheral vascular lesions with the development of hand and foot skin necrosis in a patient with COVID-19: a case report

In the presented case report, 36-year-old female patient, who was hospitalized in the rheumatology department, developed thrombotic microangiopathy and sepsis-related coronavirus disease 2019 (COVID-19). In the department, hereditary thrombophilia was revealed: heterozygous polymorphism in the coagulation factor 5 gene (Factor V Leiden). Livedo reticularis. It is known that in October 2020, the patient had COVID-19 with bilateral pneumonitis on chest computed tomography. On examination, dry gangrene of 1, 2, 4, 5 fingers of the right hand, 2 finger of the left hand, as well as 2, 3, 4, 5 fingers of the right and left feet were diagnosed. Necrosis of the nasal tip. Surgery was performed with amputation of the affected fingers and distal feet with autodermoplasty

Evaluation of Synthetic Conditions for H3PO4 Chemically Activated Rice Husk and Preparation of Honeycomb Monoliths

Activated carbons in this work were prepared from rice husk by phosphoric acid activation followed by alkaline desilication. Pseudo-random selection of 16 rice husk samples was subjected to carbonization at the following conditions: 0.5 to 2 h of activation time, 300-600 ºС and Н3РО4/precursor (wt/wt) impregnation ratio of 0.5 to 2. Concentration of NaOH desilication solution varied from 0.5 to 2M. It was found that out of the four factors impregnation ratio is clearly the strongest and at the impregnation ratio of 2 for 1 h at 500 °C N2 BET-surface area reaches 1690 m2/g (SBET (Ar)=2492 m2/g) while pore volume becomes 1.95 cm3/g. Elemental analysis showed highest carbon content for this sample (87.96%). All samples have insignificant amount of Si and traces of metals, but considerable amount of phosphorus. Blocks of honeycomb structure prepared from Ca-montmorillonite and desilicated carbonized rice husk (impregnation ratio is 1.5, 1 h at 600 ºC) have BET-surface area obtained by thermal desorption of argon up to 856 m2/g

Mesoporous Carbon-Based Rhodium Catalysts for Benzene Hydrogenation

Two different carbons, namely CAS-P-500 and CRH-P-500, were prepared from apricot stones and rice husk by H3PO4-activation at 500 ºC and H3PO4/precursor (wt/wt) impregnation ratio of 2:1 followed by water washing and desilication by NaOH solution respectively. Elemental analyses of both samples using X-ray fluorescence spectroscopy and VARIO ELEMENTAR III elemental analyzer detected up to 1% of remained phosphorus and about 88% of carbon. SEM characterization and nitrogen adsorption data revealed that highly mesoporous materials were obtained. According to BJH scheme calculations, N2 BET-surface area and pore volume for CAS-P-500 reached the values of 2030 m2/g and 1.64 cm3/g, while for CRH-P-500: 1690 m2/g and 1.95 cm3/g respectively. Activated carbons CAS-P-500 and CRH-P-500 were used as catalyst supports for the conversion of small amounts of benzene into cyclohexane to obtain cleaner gasoline. According to Euro-3 standards, gasoline should contain less than 1% of benzene, since the incomplete combustion of gasoline, which contains benzene, leads to formation of benzopyrene- a powerful carcinogen in exhaust gases. The activity of rhodium catalysts based on the CAS-P-500 and CRH-P-500 allow complete conversion of benzene into cyclohexane at 40 atm and 80oC temperature and is comparable to those of based on conventional carbons: “Sibunit”, etc

Ресурсы медицинских организаций России, оказывающих помощь при инфекционных социально значимых заболеваниях

The objective of the study: to assess the provision of the Russian medical units with resources that provide medical care for infectious socially important diseases and compare this provision with the current epidemic situation.Subjects and methods. Data from FGSN Forms no. 8, 14, 14 DS, 33, 61, 30, 47 for the Russian Federation were analyzed. The number of those died is presented as per the data of Rosstat.Results. At the working age, the mortality rate of the population is significantly affected by HIV infection, tuberculosis, viral hepatitis B and C, and the combination of these socially significant diseases (9.3%). It is difficult to determine the cause of death of the patient with multiple co-morbidities. The incidence of tuberculosis is declining more rapidly than the number of tuberculosis beds. As a result, the number of patients with tuberculosis per 1 adult tuberculosis bed decreased from 4.0 in 2005 to 2.9 in 2017; and per 1 tuberculosis bed for children aged 0-17 years – from 1.2 to 0.7 respectively. As of December 31, 2017, the average number of patients per 1 position occupied by a district phthisiologist in the Russian Federation made 306 people, including 35 people with active tuberculosis, and 8 people with multiple drug resistant tuberculosis. The existing facilities and personnel of medical tuberculosis units allow expanding their functions. Given the reduction in tuberculosis incidence, growing incidence of HIV infection, a high proportion of concurrent tuberculosis, HIV infection and viral hepatitis B and C, the best option could be the establishment of Centers for socially important infectious diseases using the facilities of medical tuberculosis units.Цель исследования: дать оценку ресурсному обеспечению медицинских организаций России, оказывающих медицинскую помощь при инфекционных социально значимых заболеваниях, в сопоставлении с эпидемической ситуацией.Материалы и методы. Проанализированы данные форм ФГСН №№ 8, 14, 14 ДС, 33, 61, 30, 47 по РФ. Численность умерших представлена по данным Росстата.Результаты. В трудоспособном возрасте на показатель смертности населения существенное влияние оказывают ВИЧ-инфекция, туберкулез, вирусные гепатиты В и С, сочетание этих социально значимых заболеваний (9,3%). При этом трудно определить причину смерти пациента при сочетанной патологии. Заболеваемость туберкулезом сокращается бóльшими темпами, чем численность туберкулезных коек. В результате число пациентов с туберкулезом на 1 туберкулезную койку для взрослых сократилось с 4,0 в 2005 г. до 2,9 в 2017 г.; на 1 туберкулезную койку для детей в возрасте 0-17 лет – с 1,2 до 0,7. Среднее число пациентов на 1 занятую должность врача-фтизиатра участкового в РФ на 31.12.2017 г. составило: всего – 306 человек, в том числе с активным туберкулезом – 35 человек, с туберкулезом с множественной лекарственной устойчивостью возбудителя – 8 человек. Материальная база и кадровый состав медицинских противотуберкулезных организаций позволяют расширить их функции. Учитывая снижение заболеваемости туберкулезом, рост заболеваемости ВИЧ-инфекцией, высокую долю сочетания туберкулеза, ВИЧ-инфекции и вирусных гепатитов В и С, оптимальным является создание на базе медицинских противотуберкулезных организаций центров инфекционных социально значимых заболеваний

Влияние дистресса на неоангиогенез у больных раком яичников

Background. Previous pre-clinical and clinical trials showed that distress experienced by cancer patients can activate the sympathetic nervous system, resulting in the elevation of the level of catecholamines in tumor tissue. catecholamines activate tumor neoangiogenesis via binding to the adrenergic receptors of tumor cells and cells of tumor microenvironment. Vascular endothelial growth factor a(VEgF a) plays a key role in tumor neoangiogenesis.Objective. To evaluate the correlation between serum VEgF alevel and distress in ovarian cancer patients.Material and methods. The prospective cross-sectional study included 100 patients with stage i–iV ovarian cancer. the median age of the patients was 56 ± 9,56 years. Enzym-linked immunosorbent assay was used for the assessment of serum VEgF alevel. distress thermometer (validated self-reported questionnaire) was used for distress diagnosis.Results. The median serum VEgF alevel was 325.77 pg/ml. aclinically significant distress was diagnosed in 54 % of patients. We found the correlation between the serum VEgF alevel and distress level in ovarian cancer patients (spearman’s rho=0.33; 95 % ci, 0.11–0.52; р< 0.004). We also found the correlation between the serum VEgR alevel and disease stage (rho=0.30; 95 % ci0.02–0.53; p<0.05). However, there was no correlation between distress and disease stage. the regression analysis method revealed that distress was an independent factor of serum VEgF aelevation in ovarian cancer patients (p<0.05).Conclusion. Assessment and early diagnosis of cancer-related distress was shown to be important for the appropriate management of ovarian cancer.Введение. По данным экспериментальных и клинических исследований, дистресс, испытываемый онкологическими пациентами, активирует симпатическую нервную систему, в результате чего повышается уровень катехоламинов в опухолевой ткани. Катехоламины, связываясь с адренорецептора-ми опухолевых клеток и клеток опухолевого микроокружения, активируют процессы неоангиогенеза опухоли. Ключевую роль в процессе неоангиогенеза опухоли играет фактор роста эндотелия сосудов семейства А (VEgF a).Цель исследования – оценить взаимосвязь уровня сывороточного VEgF aс дистрессом у больных раком яичников.Материал и методы. Проведено проспективное исследование «поперечного среза», в которое включено 100 пациенток с морфологически верифицированным раком яичников i–iV стадии, медиана возраста – 56 ± 9,56 года. Определение уровня VEgF aв сыворотке крови пациенток проводили методом иммуноферментного анализа. Для выявления дистресса применяли «Скрининговый опросник дистресса».Результаты. Медиана показателя сывороточного VEgF aу больных раком яичников составила 325,77 пг/мл. Клинически значимый дистресс был диагностирован у 54 % пациенток. Показатель сывороточного VEgF aстатистически значимо коррелировал с дистрес-сом (коэффициент ранговой корреляции Спирмена rho=0,33; 95 % ДИ=0,11–0,52, p<0,004) и стадией заболевания (rho=0,30; 95 % ДИ=0,02–0,53, p<0,05). При этом не было выявлено корреляции между дистрессом и стадией опухолевого процесса. Методом регрессионного анализа было установлено, что дистресс является независимым фактором, повышающим VEgF aв сыворотке крови больных раком яичников.Заключение. Проведенное исследование свидетельствует о важности диагностики и коррекции дистресса у больных раком яичников, так как данное состояние через стимуляцию процессов неоангиогенеза может влиять на прогрессирование опухолевого процесса