248 research outputs found
Online Εvaluation of Earth Observation Derived Indicators for Urban Planning and Management
Extensive urbanization and growth of population density have acquired a paramount interest towards a sustainable urban development. Earth Observation (EO) is an important source of information required for urban planning and management. The availability of EO data provides the immense opportunity for urban environmental indicators development easily derived by remote sensors. In this study, the state of the art methods were employed to develop urban planning and management relevant indicators that can be evaluated by using EO data. The importance of this approach lies on providing alternatives for improving urban planning and management, without consuming time and resources in collecting field or archived data. The evaluated urban indicators were integrated into a Web‐based Information System that was developed for online exploitation. The results for three case studies are therefore available online and can be used by urban planners and stakeholders in supporting their planning decisions
Catalytic and adsorptive properties of a Cu-ZSM-5 catalyst synthesized by solid-phase method
Complex 99mTc-PDA-DTPA for myocardial imaging
The 123I-labeled fatty acids such as 123I-Iodophenylpentadecanoic acid and 123I-Beta-methyliodophenylpentadecanoic acid are the agents used clinically for myocardial imaging. Fatty acids are the major source of energy for the normal myocardium. However, under ischemic conditions the myocardial cells switch to glucose metabolism for their energy needs. Fatty acids undergo prolonged metabolic stunning in patients with reversible ischemia, thereby helping in early diagnosis of coronary artery disease in highrisk patients. High cost andlimited availability of cyclotron-produced 123I, makes 99mTc-labeled fatty acids more desirable for the purpose. In diagnosis the dominant radionuclide is 99mTc. It is estimated that it is involved in about 85% of all imaging procedures in nuclear medicine. The method for preparation of new 99mTc-fatty chemical systems based on modified diethylene triamine pentaacetic acid (DTPA) molecule has been elaborated in this work . The main advantage using DTPA as chelate agent for radioactive label, is the molecule or it's derivative ability to form sufficiently stable complexes with different radioactive metals including technetium-99. Moiety of pentadecanoic acid addition gave the ability to prepare modified complex of DTPA. In a labeling procedure, freshly eluted Na99mTcO4 (20mCi) was added to a mixture of cysteine, stannous chloride, PDK-DTPA and ethanol in a vial. On keeping the reaction mixture at 90 0C for 30 min, [99mTc-PDK-DTPA] radiopharmaceutical was formed. Thereafter, the reaction mixture was cooled over ice and characterized by HPLC. The result of dynamic scintigraphic research showed, that after being injected, the substance is actively acumulated into myocardium. Eventually one can say that modified DTPA-moleculs are functionally suitable for myocardial imaging
Electromechanical instability in suspended carbon nanotubes
We have theoretically investigated electromechanical properties of freely
suspended carbon nanotubes when a current is injected into the tubes using a
scanning tunneling microscope. We show that a shuttle-like electromechanical
instability can occur if the bias voltage exceeds a dissipation-dependent
threshold value. An instability results in large amplitude vibrations of the
carbon nanotube bending mode, which modify the current-voltage characteristics
of the system
Радиомические характеристики текстурных изменений эпикардиальной жировой ткани при атеросклеротическом поражении коронарных артерий
Aim. To investigate the association of the radiomic characteristics of epicardial adipose tissue (EAT) on contrast-free computed tomography (CT) of the heart with the severity of obstructive coronary lesion and myocardial ischemia.Methods. The study included 68 patients with coronary heart disease (mean age of 63.5±9.4, 45 men and 23 women), and 15 patients (mean age 30±4.8; 14 men and 1 woman) without cardiovascular disease as a control group. All the patients underwent multispiral computed coronary angiography, coronary calcium scores (CCS) determination and stress myocardial perfusion scintigraphy. Radiomic characteristics of EAT (texture analysis by gradations of gray color) were determined on non-contrast computer tomogram images of the heart using 3D-Sliser software and the SliserRadiomics module (version 4.10.2). The obtained indicators were compared between a control and under the study groups as well as between subgroups of patients divided according to the degree of obstruction of the coronary arteries, the size of the perfusion defect, and the value of the CCS.Results. The comparative analysis of radiomic indicators of EAT between patients with coronary artery disease and the control group showed the presence of statistically significant differences between them. At the same time, the correlation analysis in the study group did not reveal any correlations between the radiomic parameters and the size of the perfusion defect, CCS or degree of stenosis of the lumen of the coronary arteries.Conclusion. The textural characteristics of EAT in patients with coronary heart disease differ from those in individuals without cardiovascular pathology. At the same time, these indicators are not associated with the severity of obstructive lesions of the coronary arteries, the value of the CCS, and the size of the perfusion defect according to scintigraphy.Цель. Исследовать ассоциацию радиомических характеристик эпикардиальной жировой ткани (ЭЖТ) на бесконтрастной компьютерной томографии (КТ) сердца с выраженностью обструктивного поражения коронарного русла и ишемии миокарда.Материалы и методы. В исследование ретроспективно включены 68 пациентов с ишемической болезнью сердца (ИБС) (средний возраст 63,5±9,4 года; 45 мужчин и 23 женщины), а также 15 лиц (средний возраст 30±4,8 года; 14 мужчин и 1 женщина) без сердечно-сосудистых заболеваний, составившие группу контроля. Всем обследуемым выполнены мультиспиральная компьютерная коронароангиография, определение индекса коронарного кальция, нагрузочная перфузионная сцинтиграфия миокарда. На бесконтрастных КТ-изображениях сердца определяли радиомические характеристики ЭЖТ (текстурный анализ по градациям серого цвета) с помощью программного обеспечения 3D-Sliser и модуля SliserRadiomics (версия 4.10.2). Полученные показатели сравнивали между группами исследования и контроля, а также в подгруппах больных, разделенных в зависимости от степени обструкции коронарных артерий, размера дефекта перфузии и значения индекса коронарного кальция.Результаты. Сравнительный анализ радиомических показателей ЭЖТ у пациентов с ИБС и группы контроля показал наличие статистически значимых различий. В то же время корреляционный анализ в группе исследования не продемонстрировал связи между радиомическими показателями и размером дефекта перфузии, индексом коронарного кальция, степенью стеноза просвета коронарных артерий.Заключение. Текстурные характеристики ЭЖТ у пациентов с ИБС отличаются от таковых у лиц без сердечно-сосудистой патологии. В то же время данные показатели не ассоциированы с выраженностью обструктивного поражения коронарных артерий, значением индекса коронарного кальция, а также размером дефекта перфузии по данным сцинтиграфии
Permafrost temperature Dynamics Along the East Siberian Transect and an Alaskan Transect (Extended Abstract)
Cytoprotective effect of non-opioid leu-enkephalin analogue in primary culture of pulmonary fibroblasts in oxidative stress
Aim. Analysis of the cytoprotective effect of non-opioid leu-enkephalin analogue (Phe-D-Ala-Gly-Phe-Leu-Arg) in the primary culture of pulmonary fibroblasts in conditions of oxidative stress.
Methods. Pulmonary fibroblasts were incubated with the peptide of non-opioid leu-enkephalin analogue (Phe-D-Ala-Gly-Phe-Leu-Arg) in the concentration 0.1 μM for 6 hours. To simulate oxidative stress, 60 μM H2O2 was added to the culture medium for 2 hours. Experimental series included (1) «control»; (2) «non-opiate leu-enkephalin analogue» (the peptide was added to the culture medium 44 hours after the final passage); (3) «oxidative stress» (H2O2 was added to the culture medium 48 hours after the final passage); (4) «non-opiate leu-enkephalin analogue + oxidative stress» (the peptide and H2O2 were added to the culture medium 44 and 48 hours respectively after the final passage). In order to evaluate the generation of superoxide anion by pulmonary fibroblasts, the method of lucigenin-dependent chemiluminescence was used. Computer morphometry of the nucleo-nucleolar apparatus of fibroblasts stained with silver nitrate by the AgNOR method was used to assess the cell state: the area of fibroblast nuclei, the total nucleoli area in the nucleus, and the number of nucleoli in the nucleus were measured. These parameters correlate with the activity of anabolic processes in the cells.
Results. The effect of H2O2 on the primary culture of pulmonary fibroblasts caused an increase of superoxide anion generation by the fibroblasts, reduction of fibroblast nuclei size, decrease of nucleoli amount and size. Pre-incubation of pulmonary fibroblasts with a non-opioid leu-enkephalin analogue reduced the H2O2-induced generation of superoxide anion, corrected changes in the nucleo-nucleolar apparatus of fibroblasts caused by oxidative stress. In our previous studies, similar effect in the same model was shown for non-selective μ/δ-opioid receptor agonist peptide sedatin (dermorphin analogue). The mechanism of cytoprotective effect of non-opioid leu-enkephalin analogue may include the affinity of this peptide to nociceptin receptors (NOR receptors) that requires further studies.
Conclusion. The results of the study indicate a direct cytoprotective effect of the peptide Phe-D-Ala-Gly-Phe-Leu-Arg (non-opioid leu-enkephalin analogue) in oxidative stress
Changes in aortic root dimensions after ascending aortic repair with concomitant aortic valve replacement
The issue of ascending aortic repair with concomitant aortic valve replacement in pa-tients with ascending aortic aneurysm (AscAA) and aortic valve stenosis is still debatable.Aim. To analyze the dimension changes of the preserved aortic root after simultaneous ascending aorta repair and aortic valve replacement.Material and methods. This retrospective study included 102 patients who, from December 2012 to May 2022, underwent simultaneous aortic valve replacement and ascending aorta repair with hemiarch replacement. Patients were divided into 2 following groups based on the aortic valve morphology: group 1 — patients with bicuspid aortic valve (BAV) and AscAA (n=75), group 2 — patients with tricuspid aortic valve (TAV) and AscAA (n=27). Depending on the presence of aortic root dilatation (maximum diameter (d) >40 mm), each of the groups was additionally stratified into 2 more subgroups as follows: patients without aortic root dilatation (d≤40 mm) and patients with its dilatation (d>40 mm). The dynamics of the aortic root diameter was assessed by computed tomography angiography.Results. The mean follow-up period for patients was 36,2±14,6 months. Survival rate in the BAV+AscAA and TAV+AscAA groups was 96% and 100%, respectively (p=0,380). Freedom from aortic root resurgery was 100% in both study groups. In patients with dilated and non-dilated aortic root of the BAV+AscAA group, an increase in aortic root dimension was noted at a rate of 0,65±0,51 mm/year and 0,32±0,27 mm/year, respectively. In patients of the TAV+AscAA group, a regression in dilated and non-dilated aortic root diameter was observed as follows: 0,93±0,48 mm/year and 0,56±0,43 mm/year, respectively.Conclusion. In patients with AscAA in combination with BAV stenosis after a singlestep surgical intervention, a weak negative dynamics of non-dilated and dilated aortic root is observed in the mid-term follow-up period. In patients with AscAA and TAV, there is involutive alterations of the aortic root dimension during 3-year follow-up
Prediction of Bodyweight and Energy Expenditure Using Point Pressure and Foot Acceleration Measurements
Bodyweight (BW) is an essential outcome measure for weight management and is also a major predictor in the estimation of daily energy expenditure (EE). Many individuals, particularly those who are overweight, tend to underreport their BW, posing a challenge for monitors that track physical activity and estimate EE. The ability to automatically estimate BW can potentially increase the practicality and accuracy of these monitoring systems. This paper investigates the feasibility of automatically estimating BW and using this BW to estimate energy expenditure with a footwear-based, multisensor activity monitor. The SmartShoe device uses small pressure sensors embedded in key weight support locations of the insole and a heel-mounted 3D accelerometer. Bodyweight estimates for 9 subjects are computed from pressure sensor measurements when an automatic classification algorithm recognizes a standing posture. We compared the accuracy of EE prediction using estimated BW compared to that of using the measured BW. The results show that point pressure measurement is capable of providing rough estimates of body weight (root-mean squared error of 10.52 kg) which in turn provide a sufficient replacement of manually-entered bodyweight for the purpose of EE prediction (root-mean squared error of 0.7456 METs vs. 0.6972 METs). Advances in the pressure sensor technology should enable better accuracy of body weight estimation and further improvement in accuracy of EE prediction using automatic BW estimates
The study of interaction of modified fatty acid with {99m}Tc in alcoholic media
The paper presents the results of laboratory research aimed at the development of methods of synthesis of new radiodiagnostic agents based on modified fatty acid labelled with technetium-99m intended for scintigraphic evaluation of myocardial metabolism. In particular, the interaction of substance with {99m}Tc in alcoholic media and the use of ethanol as solvent in the synthesis of the radiopharmaceutical were studied
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