scholarly journals Study of haemolytic properties of a disk-type pump

2020 ◽  
Vol 24 (1) ◽  
pp. 87
Author(s):  
M. O. Zhulkov ◽  
A. M. Golovin ◽  
E. O. Golovina ◽  
A. S. Grenadyorov ◽  
A. V. Fomichev ◽  
...  
Keyword(s):  
Conflict Of Interest ◽  
Mechanical Stability ◽  
Operating Time ◽  
Operating Mode ◽  
Test Method ◽  
Hydrodynamic Resistance ◽  
Russian Science ◽  
Blood Samples ◽  
Pump Operation ◽  
Free Haemoglobin

<p><strong>Background.</strong> A shortage of donor organs is one of the urgent problems of transplantology. Despite the current level of technology, there are a number of difficult barriers to overcome. Because of the high demand for assisted circulatory devices, the work caused by the creation of the most physiological and biocompatible model of the apparatus, exceptional relevance is provided.</p><p><strong>Aim</strong>. To evaluate the haemolytic properties of the auxiliary circulatory apparatus based on a disk-type pump.</p><p><strong>Methods.</strong> A hydrodynamic bench was created to conduct haemolysis tests of a disk-type pump. The bench consisted of a tank, a heat exchanger, hydrodynamic resistance, connecting tubes, a blood sampling port, a pressure and flow measurement system, and a test pump. The test method consisted of assessing the level of free plasma haemoglobin (pHb) obtained by taking blood samples during pump operation in the operating mode (2300–2500 rpm, 5–6 l/min, pressure drop at the clamp level of 100 mmHg). Standardized haemolysis indices (NIH and MIH) were calculated based on the data obtained. The indices were calculated based on the analysis of free haemoglobin in the plasma of blood samples, haematocrit, total haemoglobin, blood flow, and pump operating time.</p><p><strong>Results.</strong> Bench tests (n = 5) revealed that the average level of free haemoglobin was 2.2 mg/%. This confirms the absolute atraumatic nature of the design of a new type of pump. The calculated values of the haemolysis indices were: NIH - 0.0013 and MIH - 1.88. This proves the fundamental possibility of using a disk-type pump as a basis for creating auxiliary circulatory devices.<br /><strong>Conclusion.</strong> The developed methodology for assessing the mechanical stability of red blood cells allows you to give objective information about one of the most important safety criteria for auxiliary circulatory devices i.e., the level of haemolysis. The results obtained revealed that it is possible and safe to use a disk-type pump as an auxiliary circulatory device.</p><p>Received 16 December 2019. Revised 10 March 2020. Accepted 13 March 2020.</p><p><strong>Funding:</strong> The research is supported by a grant of the Russian Science Foundation (project No. 19-19-00186).</p><p><strong>Conflict of interest:</strong> Authors declare no conflict of interest.</p><p><strong>Author contributions</strong> <br />Conception and study design: M.O. Zhulkov<br />Data collection and analysis: M.O. Zhulkov, A.S. Grenadyorov, A.M. Golovin, E.O. Golovina, A.V. Fomichev, S.A. Alsov<br />Drafting the article: M.O. Zhulkov, A.S. Grenadyorov <br />Critical revision of the article: M.O. Zhulkov, A.M. Chernyavskiy<br />Final approval of the version to be published: M.O. Zhulkov A.S. Grenadyorov, A.M. Golovin, E.O. Golovina, A.V. Fomichev, S.A. Alsov, A.M. Chernyavskiy</p>

In vitro effects of temperature on red blood cell deformability and membrane stability in human and various vertebrate species

2021 ◽  
pp. 1-10
Author(s):  
Adam Attila Matrai ◽  
Gabor Varga ◽  
Bence Tanczos ◽  
Barbara Barath ◽  
Adam Varga ◽  
...  
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Whole Blood ◽  
Mechanical Stability ◽  
Cell Deformability ◽  
Blood Samples ◽  
Effects Of Temperature ◽  
The Way ◽  
Rbc Deformability

BACKGROUND: The effects of temperature on micro-rheological variables have not been completely revealed yet. OBJECTIVE: To investigate micro-rheological effects of heat treatment in human, rat, dog, and porcine blood samples. METHODS: Red blood cell (RBC) - buffer suspensions were prepared and immersed in a 37, 40, and 43°C heat-controlled water bath for 10 minutes. Deformability, as well as mechanical stability of RBCs were measured in ektacytometer. These tests were also examined in whole blood samples at various temperatures, gradually between 37 and 45°C in the ektacytometer. RESULTS: RBC deformability significantly worsened in the samples treated at 40 and 43°C degrees, more expressed in human, porcine, rat, and in smaller degree in canine samples. The way of heating (incubation vs. ektacytometer temperation) and the composition of the sample (RBC-PBS suspension or whole blood) resulted in the different magnitude of RBC deformability deterioration. Heating affected RBC membrane (mechanical) stability, showing controversial alterations. CONCLUSION: Significant changes occur in RBC deformability by increasing temperature, showing inter-species differences. The magnitude of alterations is depending on the way of heating and the composition of the sample. The results may contribute to better understanding the micro-rheological deterioration in hyperthermia or fever.

scholarly journals Evaluation of a Preclinical Blood Test for Scrapie in Sheep Using Immunocapillary Electrophoresis

2006 ◽  
Vol 89 (3) ◽  
pp. 720-727 ◽  
Author(s):  
Roy Jackman ◽  
David J Everest ◽  
Mary Jo Schmerr ◽  
Mohammed Khawaja ◽  
Pat Keep ◽  
...  
Keyword(s):  
Capillary Electrophoresis ◽  
Prion Protein ◽  
Clinical Signs ◽  
Test System ◽  
Buffy Coat ◽  
Infected Sheep ◽  
Test Method ◽  
Peptide Sequence ◽  
Transmissible Spongiform Encephalopathies ◽  
Blood Samples

Abstract An analytical method is described for detection of endogenous disease-associated prion protein in the buffy coat fraction from the blood of sheep infected with scrapie. The method has been improved and evaluated for its performance in the preclinical diagnosis of ovine transmissible spongiform encephalopathies. The test system uses a protocol for sample preparation that includes extraction and concentration and a test method that uses a liquid-phase competitive immunoassay for prion protein. Antibodies directed to a peptide sequence at the C-terminus of the prion protein (PrP) and a fluorescein-labeled peptide conjugate are used in the assay. Free zone capillary electrophoresis with laser-induced fluorescence for detection is used to separate the antibody-bound fluorescently labeled peptide and free labeled peptide. In this assay, the PrP competes with the fluorescently labeled peptide for limited antibody binding sites, which results in a reduction of the peak representing the immunocomplex of the antibody bound to the fluorescently labeled peptide. When blood samples from scrapie-infected sheep aged 712 months and of the scrapie-susceptible PrP genotypes VRQ/VRQ and VRQ/ARQ were analyzed, the abnormal PrP was found in blood samples. These results correlated with the post-mortem diagnosis of scrapie. The sheep were preclinical and appeared normal at the time of testing but later died with clinical disease approximately 12 months after testing. In older animals, and those with clinical signs, a smaller percentage of animals tested positive. This study has demonstrated that this technology can be used as a sensitive, rapid preclinical test to detect the disease-associated PrP in the blood of scrapie-infected sheep. Improvements in the extraction protocol and capillary electrophoresis conditions will enhance the robustness of this test.

scholarly journals Test Results of a Polymer Radiator of MTZ-80 Tractor Cooling System

2020 ◽  
Vol 14 (1) ◽  
pp. 55-60
Author(s):  
O. N. Didmanidze ◽  
R. T. Khakimov ◽  
E. P. Parlyuk ◽  
N. A. Bol’shakov
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Cooling System ◽  
Operating Mode ◽  
Aerodynamic Characteristics ◽  
Operating Conditions ◽  
Hydrodynamic Resistance ◽  
Measuring Instruments ◽  
Research Areas ◽  
In Series

Global car manufacturers wish to increase the number of manufactured products, reduce their cost and labor input. The choice of research areas, design and technological developments in radiator construction is an extremely important and urgent task, due to the mass production of radiators for tractors and automobiles on the one hand, and the favorable development prospects of these interrelated industries, on the other. (Research purpose) To substantiate theoretically and experimentally the use of a combined cooling system containing both aluminum and polymeric water radiators and similarly liquid-oil heat exchangers based on the four principles listed above on automobiles and tractors. (Materials and methods) The authors performed bench tests using a special wind tunnel to study the thermal and aerodynamic characteristics of a prototype tractor radiator with a polyurethane core. After reaching the steady-state operating mode of the installation, the experimental values were determined for the control and measuring instruments. (Results and discussion) The authors carried out measurements of all parameters of both coolants in series at each steady-state operating mode of the bench. They obtained the main indicators dependences (reduced heat transfer, aerodynamic and hydraulic drag) of the heat exchanger, close to the operating conditions of the vehicles. (Conclusions) A prototype MTZ-80 radiator with a polyurethane core has great prospects as a future alternative radiator. An increase by 10-15 percent in the radiator heat transfer is possible by using aluminum fi ns on the surface of the polyurethane plate. A 15-20 percent reduction in hydrodynamic resistance is achieved by increasing the diameter of the capillary throughput in a polyurethane plate and the number of plates themselves in the radiator cell.

scholarly journals The Analysis of Electrical Energy Consumption of the Impact Screwdriver During Assembly of Fixed Threaded Joints

2017 ◽  
Vol 54 (3) ◽  
pp. 50-57 ◽  
Author(s):  
I. Grinevich ◽  
Vl. Nikishin ◽  
N. Mozga ◽  
M. Laitans
Keyword(s):  
Energy Consumption ◽  
Operating Time ◽  
Electrical Energy ◽  
Operating Mode ◽  
Electrical Energy Consumption ◽  
Impact Mechanism ◽  
Threaded Joints ◽  
Rotor Head ◽  
Product Costs ◽  
The Impact

Abstract The paper deals with the possibilities of reducing the consumption of electrical energy of the impact screwdriver during the assembly of fixed threaded joints. The recommendations related to a decrease in electrical energy consumption would allow reducing product costs but so far there have been no such recommendations from the producers of the tool as to the effective operating regimes of the impact screwdrivers in relation to electrical energy consumption and necessary tightening moment of the nut. The aim of the study is to find out the economical operating mode of the electrical impact screwdriver when assembling fixed threaded joints. By varying the set speed of the rotor head and working time of the impact mechanism, there is an opportunity to determine electrical energy consumption of the tool for the given tightening moment. The results of the experiment show that at the same tightening moment obtained the electrical energy consumption of the impact screwdriver is less at a higher starting set speed of the rotor head but shorter operating time of the impact mechanism than at a lower speed of the rotor head and longer operating time of the impact mechanism.

scholarly journals Impact of Number of Operators and Distance to Branch Piles on Woodchipper Operation

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 598 ◽  
Author(s):  
Łukasz Warguła ◽  
Mateusz Kukla ◽  
Piotr Krawiec ◽  
Bartosz Wieczorek
Keyword(s):  
Low Power ◽  
Adaptive Systems ◽  
Operating Time ◽  
Operating Mode ◽  
Operating Conditions ◽  
Operating Condition ◽  
Time Frequency ◽  
Drive Speed ◽  
Type Machine ◽  
Volume Output

Branch chipping machines with low-power engines are distinguished with an intermittent operation due to a periodical supply of branches. A conventional drive speed control of these machines is not adapted to adjust the operating mode depending on frequency of material supply for shredding. This article discusses the issues related to the assessment of the application of adaptive systems similar in design to start–stop systems used in vehicles, as necessary in the driving of this type machine. During testing, an impact of a distance between a branch pile from the woodchipper, a number of operators on frequency of drive unit operating condition changes, and the mass and volume output (productivity) were considered. A percentage ratio of the active and passive (idle) operation in selected conditions of use was also determined. A low-power 9.5 kW engine-powered cylindrical-type woodchipper was used for testing. Material chopped in the chipper was freshly cut branches of oaks (Quercus L. Sp. Pl. 994. 1753) with a diameter in the largest cross-section ca. 80 mm and moisture content ca. 25%. Piles of branches were located at three different distances from the chipper, i.e., 3 m, 9 m and 15 m. Branches to the chipper were fed by one or two operators. It was demonstrated that the idle run time in tested conditions with one operator could be from 43% to 71% of the entire operating time. Frequency of operating condition changes when only one operator worked and fluctuated from ca. 6 to 2 times per minute. Increasing the number of operators from one to two had a slight impact on the frequency of operating condition changes (by ca. 7%) at the shortest distance from the chipper (3 m). However, at larger distances, the additional operator may increase the frequency of operating condition changes of the chipper by 77% for 9 m distance and 85% for 15 m distance. The mass and volumetric output of the cylindrical chipper in the most advantageous case is equal to 0.66 t/h and 3.5 m3/h, respectively. The increase of the branch pile distance from the chipper causes a drop in mass output by 32%, and volumetric output by 33.5%. The results of the tests confirmed the necessity for the development of low-power chipping machines designed for clearing operations rather than industrial production of biomass. A direction for development could be systems that adapt driving units to operating conditions, depending on a demand for the chipping process.

scholarly journals Non-invasive electrophysiological cardiac mapping from development to practice

2020 ◽  
Vol 24 (4) ◽  
pp. 33
Author(s):  
E. A. Artyukhina ◽  
M. V. Yashkov ◽  
A. Sh. Revishvili
Keyword(s):  
Real Time ◽  
Conflict Of Interest ◽  
Diagnostic Method ◽  
Cardiac Mapping ◽  
Russian Science ◽  
Non Invasive ◽  
Preoperative Stage ◽  
Optimal Technology ◽  
History Of ◽  
Mapping Systems

<p>In modern interventional arrhythmology, invasive endocardial mapping systems can eliminate arrhythmias with a high degree of efficiency. However, invasive mapping systems have several disadvantages, such as: the invasiveness of the method, which requires some preparation and has a number of limitations; the impossibility of simultaneous determination of electrophysiological processes occurring throughout the heart; the complexity of mapping when the arrhythmia focus is located in hard-to-reach anatomical structures; localization of the focus on the epicardial surface of the heart and occasional and difficult-to-induce arrhythmias during surgery.<br />In clinical practice, it became necessary to develop and implement systems for superficial non-invasive electrophysiological mapping of the heart. The main difference between superficial non-invasive electrophysiological mapping of the heart and other techniques is that after processing all the information, it is possible to receive a holistic picture of electrophysiological processes occurring throughout the heart in real time instead of receiving separately recorded signals and information from several chambers of the heart.<br />In this article, we describe the history of the development and implementation of superficial non-invasive electrophysiological cardiac mapping and the potential use of the diagnostic method in treating the various types of arrhythmias. A brief technique of carrying out this diagnostic method is described. Further directions regarding the development and improvement of this research method are also discussed, such as developing and improving the system for visualizing heart processes occurring in real time, improving the treatment of patients with cardiac arrhythmias, introducing non-invasive mapping of heart data into the systems used for invasive electroanatomical mapping of the heart and integrating the method with systems for non-invasive ablation.<br />The non-invasive mapping system of the heart is a modern progressive and constantly evolving diagnostic method that enables visualizing the electrophysiological processes occurring in the human heart with high accuracy in a non-invasive manner. To determine tactics of treatment, decide on an interventional approach and select the optimal technology at the preoperative stage for treating patients with various rhythm disturbances in their hearts.</p><p>Received 19 November 2020 г. Revised 9 December 2020 г. Accepted 14 December 2020 г.</p><p><strong>Funding:</strong> The work is supported by a grant of the Russian Science Foundation (project No. 19-15-00406).</p><p><strong>Conflict of interest:</strong> Authors declare no conflict of interest.</p>

scholarly journals Effect of Initial Water Flux on the Performance of Anaerobic Membrane Bioreactor: Constant Flux Mode versus Varying Flux Mode

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 203
Author(s):  
Xiawen Yi ◽  
Meng Zhang ◽  
Weilong Song ◽  
Xinhua Wang
Keyword(s):  
Membrane Fouling ◽  
Membrane Surface ◽  
Water Flux ◽  
Operating Time ◽  
Operating Mode ◽  
Initial Water ◽  
Constant Flux ◽  
Membrane Performance ◽  
Fouling Mitigation ◽  
Flux Mode

Anaerobic membrane bioreactors (AnMBRs) have aroused growing interest in wastewater treatment and energy recovery. However, serious membrane fouling remains a critical hindrance to AnMBRs. Here, a novel membrane fouling mitigation via optimizing initial water flux is proposed, and its feasibility was evaluated by comparing the membrane performance in AnMBRs between constant flux and varying flux modes. Results indicated that, compared with the constant flux mode, varying flux mode significantly prolonged the membrane operating time by mitigating membrane fouling. Through the analyses of fouled membranes under two operating modes, the mechanism of membrane fouling mitigation was revealed as follows: A low water flux was applied in stage 1 which slowed down the interaction between foulants and membrane surface, especially reduced the deposition of proteins on the membrane surface and formed a thin and loose fouling layer. Correspondingly, the interaction between foulants was weakened in the following stage 2 with a high water flux and, subsequently, the foulants absorbed on the membrane surface was further reduced. In addition, flux operating mode had no impact on the contaminant removal in an AnMBR. This study provides a new way of improving membrane performance in AnMBRs via a varying flux operating mode.

scholarly journals Anemia Diagnosis on a Simple Paper-based Assay

2018 ◽  
Author(s):  
Sujay K Biswas ◽  
Soumya Bandyopadhyay ◽  
Shantimoy Kar ◽  
Nirmal K Som ◽  
Suman Chakraborty
Keyword(s):  
Gold Standard ◽  
Diagnostic Tests ◽  
State Of The Art ◽  
Wide Spectrum ◽  
Point Of Care ◽  
Test Method ◽  
High Fidelity ◽  
Neonatal Mortality Rate ◽  
Blood Samples ◽  
Mild Anemia

AbstractIn developing countries, the maternal and neonatal mortality rate is often affected by prenatal period anemia, a preventable and ubiquitous impairment attributed due to low hemoglobin (Hgb) concentration. We report the development of a simple, frugal (~ 0.02 $ per test), rapid and high fidelity paper-based colorimetric microfluidic device for point-of-care (POC) detection of anemia. We validate our findings with 32 blood samples collected from different patients covering a wide spectrum of anemia and subsequently, compare with standard pathological results measured using a hematology analyzer. POC based Hgb estimates are correlated with the pathological gold standard estimates of Hgb levels (r = 0.909), and the POC test method yielded similar sensitivity and specificity for detecting mild anemia (n = 8) (<11 g/dl) (sensitivity: 87.5%, specificity: 100 %) and for severe anemia (n = 3) (<7 g/dl) (sensitivity: 100 %, specificity: 100 %). The estimated Hgb levels are, within 1.5 g/dl from the pathological estimate, for 91 % of the blood samples. Results demonstrate the elevated efficacy and viability of this POC colorimetric diagnostic test, in comparison to the state-of-the-art complex and expensive diagnostic tests for anemia detection.

scholarly journals Microstructural Changes during High Temperature Service of a Cobalt-Based Superalloy First Stage Nozzle

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
A. Luna Ramírez ◽  
J. Porcayo-Calderon ◽  
Z. Mazur ◽  
V. M. Salinas-Bravo ◽  
L. Martinez-Gomez
Keyword(s):  
Gas Turbines ◽  
Microstructural Analysis ◽  
Operating Time ◽  
Operating Mode ◽  
Residual Lifetime ◽  
Lifetime Estimation ◽  
Nickel Iron ◽  
Catastrophic Failures ◽  
Main Components

Superalloys are a group of alloys based on nickel, iron, or cobalt, which are used to operate at high temperatures (T> 540°C) and in situations involving very high stresses like in gas turbines, particularly in the manufacture of blades, nozzles, combustors, and discs. Besides keeping its high resistance to temperatures which may approach 85% of their melting temperature, these materials have excellent corrosion resistance and oxidation. However, after long service, these components undergo mechanical and microstructural degradation; the latter is considered a major cause for replacement of the main components of gas turbines. After certain operating time, these components are very expensive to replace, so the microstructural analysis is an important tool to determine the mode of microstructure degradation, residual lifetime estimation, and operating temperature and most important to determine the method of rehabilitation for extending its life. Microstructural analysis can avoid catastrophic failures and optimize the operating mode of the turbine. A case study is presented in this paper.

scholarly journals FEATURES OF FLUE GAS CLEANING IN WET SCRUBBERS WITH VENTURI PIPE AT EXCESS SPRAYING

2018 ◽  
pp. 41-50
Author(s):  
I.A. Volchyn ◽  
V.A. Raschepkin
Keyword(s):  
Fly Ash ◽  
Flue Gas ◽  
Gas Flow ◽  
Droplet Diameter ◽  
Operating Mode ◽  
Hydrodynamic Resistance ◽  
Gas Cleaning ◽  
Wet Gas ◽  
Wet Scrubbers ◽  
Venturi Pipe

The radical increase in the density of spraying the flue gas stream in wet Venturi scrubbers allows to significantly increase the efficiency of these dust precipitators to the level of compliance with the European requirements for dust emissions. Such a shift in the operating mode significantly affects the nature of the processes of heat and mass transfer and has feature sthat are important to consider when reconstructing and designing wet gas cleaning plants. The mathematical modeling of the process of flue gas cleaning from fly ash particles in wet Venturi scrubbers in the conditions of excess spraying is performed, the dynamics of the main thermophysical parameters of the heterogeneous flow in a medium with variable moisture content and the influence of the droplet diameter on the efficiency of wet scrubbers are investigated. The problem of changing hydrodynamic resistance of a wet scrubber at different gas flow spraying densities has been studied; the effect of the input fly ash particles distribution on the result of dust cleaning is estimated. Bibl. 26, Fig. 5, Tab. 1.

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