scholarly journals A Real-Time Programmable Pulsatile Flow Pump for In Vitro Cardiovascular Experimentation

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Rahul Raj Mechoor ◽  
Tyler Schmidt ◽  
Ethan Kung
Keyword(s):  
Pulsatile Flow ◽  
Low Cost ◽  
Gear Pump ◽  
Scientific Software ◽  
Flow Rates ◽  
Feedback Algorithm ◽  
Anatomic Locations ◽  
Flow Waveforms ◽  
Flow Pump

Benchtop in vitro experiments are valuable tools for investigating the cardiovascular system and testing medical devices. Accurate reproduction of the physiologic flow waveforms at various anatomic locations is an important component of these experimental methods. This study discusses the design, construction, and testing of a low-cost and fully programmable pulsatile flow pump capable of continuously producing unlimited cycles of physiologic waveforms. It consists of a gear pump actuated by an AC servomotor and a feedback algorithm to achieve highly accurate reproduction of flow waveforms for flow rates up to 300 ml/s across a range of loading conditions. The iterative feedback algorithm uses the flow error values in one iteration to modify the motor control waveform for the next iteration to better match the desired flow. Within four to seven iterations of feedback, the pump replicated desired physiologic flow waveforms to within 2% normalized RMS error (for flow rates above 20 mL/s) under varying downstream impedances. This pump device is significantly more affordable (∼10% of the cost) than current commercial options. More importantly, the pump can be controlled via common scientific software and thus easily implemented into large automation frameworks.

Constant Blood Flow during Single-Needle Dialysis is Unnecessary

1993 ◽  
Vol 16 (7) ◽  
pp. 505-509 ◽  
Author(s):  
H.D. Polaschegg ◽  
R. Wojke
Keyword(s):  
Blood Flow ◽  
Vascular Access ◽  
Pulsatile Flow ◽  
Tidal Flow ◽  
Constant Flow ◽  
Pulsatile Blood Flow ◽  
Flow Rates ◽  
Flow Through ◽  
Optimal Efficiency

Single-needle (SN) dialysis employs tidal blood flow at the point of vascular access. The simplest SN systems convert this tidal flow to a pulsatile flow in the dialyser. It has been assumed that constant flow through the dialyser is necessary for optimal efficiency. Therefore SN blood circuits are designed to smooth the pulsatile flow in the dialyser to a relatively constant flow. This increases the complexity and cost of the SN system. In order to test the hypothesis that pulsatile flow results in lower clearances than constant flow, we performed measurements of clearance in vitro using pulsatile blood flow at time-averaged rates of 50-250 ml/min and tidal volumes 200-100 ml/min. These were compared with clearances using constant blood flow at the same rates. At all flow rates and at tidal volumes up to 50 ml, the clearance measurements obtained during pulsatile flow were identical to those obtained during constant flow.

Hemodialysis: Evidence of Enhanced Molecular Clearance and Ultrafiltration Volume by Using Pulsatile Flow

1993 ◽  
Vol 16 (9) ◽  
pp. 645-652 ◽  
Author(s):  
T.M. Runge ◽  
J.C. Briceño T. ◽  
M.E. Sheller ◽  
C.E. Moritz ◽  
L. Sloan ◽  
...  
Keyword(s):  
Steady Flow ◽  
Hollow Fiber ◽  
Pulsatile Flow ◽  
Vitamin B ◽  
In Vitro Experiments ◽  
Roller Pump ◽  
Flow Rates ◽  
Pulsatile Pump ◽  
Vitamin B 12

We describe several in vitro experiments showing evidence that pulsatile flow hemodialysis enhances ultrafiltration volume and molecular clearance as compared with steady flow hemodialysis. A new pulsatile pump and a conventional roller pump were compared using different hollow fiber dialyzers and a simulated blood solution containing urea, aspartame and vitamin B-12 at different flow rates and configurations. Ultrafiltration volume and concentration of urea, aspartame and B-12 were measured and molecular clearance (K) calculated. Ultrafiltration volume markedly increased with pulsatile flow. After 10 min K for urea with pulsatile flow was higher in all experiments even when ultrafiltration was prevented. Clearance of aspartame and B-12 also increased with pulsatile flow. We propose three mechanisms by which pulsatile flow is more efficient than steady flow hemodialysis: greater fluid energy, avoidance of molecular channeling and avoidance of membrane layering. We hypothesize that using pulsatile flow in hemodialysis can significantly shorten the duration of dialysis sessions for most of the patients, and consequently reduce the duration of the procedure and its cost.

Natural Bioactive Compounds As Adjuvant Therapy For Hepatitis C Infection

2020 ◽  
Vol 16 ◽  
Author(s):  
Moema S. Santana ◽  
Rute Lopes ◽  
Isabela H. Peron ◽  
Carla R. Cruz ◽  
Ana M. M. Gaspar ◽  
...  
Keyword(s):  
Hepatitis C ◽  
Bioactive Compounds ◽  
Low Cost ◽  
Chemical Diversity ◽  
Acute Hepatitis C ◽  
Hepatitis C Infection ◽  
Middle Income ◽  
Broad Perspective ◽  
Cost Of Production

Background: Hepatitis C virus infection is a significant global health burden, which causes acute or chronic hepatitis. The acute hepatitis C is generally asymptomatic and progresses to cure, while persistent infection can progress to chronic liver disease and extrahepatic manifestations. Standard treatment is expensive, poorly tolerated, and has variable sustained virologic responses amongst the different viral genotypes. New therapies involve direct acting antivirals; however, it is also very expensive and may not be accessible for all patients worldwide. In order to provide a complementary approach to the already existing therapies, natural bioactive compounds are investigated as to their several biologic activities, such as direct antiviral properties against hepatitis C, and effects on mitigating chronic progression of the disease, which includes hepatoprotective, antioxidant, anticarcinogenic and anti-inflammatory activities; additionally, these compounds present advantages, as chemical diversity, low cost of production and milder or inexistent side effects. Objective: To present a broad perspective on hepatitis C infection, the chronic disease, and natural compounds with promising anti-HCV activity. Methods: This review consists of a systematic review study about the natural bioactive compounds as a potential therapy for hepatitis C infection. Results: The quest for natural products have yielded compounds with biologic activity, including viral replication inhibition in vitro, demonstrating antiviral activity against hepatitis C. Conclusion: One of the greatest advantages of using natural molecules from plant extracts is the low cost of production, not requiring chemical synthesis, which can lead to less expensive therapies available to low and middle-income countries.

Causes of gear pump fails and methods for their elimination

2020 ◽  
pp. 98-107
Author(s):  
Vitaliy A. Zuyevskiy ◽  
Daniil O. Klimyuk ◽  
Ivan A. Shemberev
Keyword(s):  
Adhesion Strength ◽  
Production Systems ◽  
Low Cost ◽  
High Strength ◽  
Strength Properties ◽  
Research Purpose ◽  
Working Fluid ◽  
Gear Pump ◽  
Repair Service ◽  
Recovery Method

Gear pumps are an important element of many production systems and their replacement in case of failure can be quite expensive, so it is important to have a modern and well-tuned technology for their recovery. There are many methods for restoring the pump's performance, depending on the reason that led to its failure. (Research purpose) The research purpose is in determining what causes most often lead to loss of pump performance, and developing a recovery method that provides the greatest post-repair service life of the pump and low cost of repair. (Materials and methods) Authors took into account that the applied coatings must have sufficient adhesion strength and resistance to mechanical, thermal and corrosion loads during operation. It was found that most often significant leaks of the working fluid, leading to failure, occur due to an increase in the gap between the inner surface of the housing and the gears due to active wear of the housing wells. Authors determined that the method of electric spark treatment of worn-out housing wells is best suited to perform the task (a large post-repair resource and low costs). (Results and discussion) It was found by laboratory studies of the adhesion strength of electric spark coatings with various electrodes that the best transfer of the material to the substrate is provided by bronze electrodes BrMKts3-1. It was noted that the coatings applied using the BrMKts3-1 electrode have high strength properties. (Conclusions) Research conducted in the center for collective use "Nano-Center" VIM confirmed the possibility of effective recovery of the gear pump by electric spark treatment.

scholarly journals Generation of High-Yield, Functional Oligodendrocytes from a c-myc Immortalized Neural Cell Line, Endowed with Staminal Properties

2021 ◽  
Vol 22 (3) ◽  
pp. 1124
Author(s):  
Mafalda Giovanna Reccia ◽  
Floriana Volpicelli ◽  
Eirkiur Benedikz ◽  
Åsa Fex Svenningsen ◽  
Luca Colucci-D’Amato
Keyword(s):  
Cell Line ◽  
Low Cost ◽  
Neural Cell ◽  
New Drugs ◽  
High Yield ◽  
Time Saving ◽  
Interacting Protein ◽  
Neuronal Marker ◽  
Differentiation Status

Neural stem cells represent a powerful tool to study molecules involved in pathophysiology of Nervous System and to discover new drugs. Although they can be cultured and expanded in vitro as a primary culture, their use is hampered by their heterogeneity and by the cost and time needed for their preparation. Here we report that mes-c-myc A1 cells (A1), a neural cell line, is endowed with staminal properties. Undifferentiated/proliferating and differentiated/non-proliferating A1 cells are able to generate neurospheres (Ns) in which gene expression parallels the original differentiation status. In fact, Ns derived from undifferentiated A1 cells express higher levels of Nestin, Kruppel-like factor 4 (Klf4) and glial fibrillary protein (GFAP), markers of stemness, while those obtained from differentiated A1 cells show higher levels of the neuronal marker beta III tubulin. Interestingly, Ns differentiation, by Epidermal Growth Factors (EGF) and Fibroblast Growth Factor 2 (bFGF) withdrawal, generates oligodendrocytes at high-yield as shown by the expression of markers, Galactosylceramidase (Gal-C) Neuron-Glial antigen 2 (NG2), Receptor-Interacting Protein (RIP) and Myelin Basic Protein (MBP). Finally, upon co-culture, Ns-A1-derived oligodendrocytes cause a redistribution of contactin-associated protein (Caspr/paranodin) protein on neuronal cells, as primary oligodendrocytes cultures, suggesting that they are able to form compact myelin. Thus, Ns-A1-derived oligodendrocytes may represent a time-saving and low-cost tool to study the pathophysiology of oligodendrocytes and to test new drugs.

scholarly journals Designing of an Advanced Compression Bioreactor with an Implementation of a Low-Cost Controlling System Connected to a Mobile Application

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 915
Author(s):  
Gözde Dursun ◽  
Muhammad Umer ◽  
Bernd Markert ◽  
Marcus Stoffel
Keyword(s):  
Mobile Application ◽  
Low Cost ◽  
Experimental Information ◽  
Raspberry Pi ◽  
Tissue Constructs ◽  
Cost Controlling ◽  
Controlling System ◽  
And Control ◽  
Tissue Models

(1) Background: Bioreactors mimic the natural environment of cells and tissues by providing a controlled micro-environment. However, their design is often expensive and complex. Herein, we have introduced the development of a low-cost compression bioreactor which enables the application of different mechanical stimulation regimes to in vitro tissue models and provides the information of applied stress and strain in real-time. (2) Methods: The compression bioreactor is designed using a mini-computer called Raspberry Pi, which is programmed to apply compressive deformation at various strains and frequencies, as well as to measure the force applied to the tissue constructs. Besides this, we have developed a mobile application connected to the bioreactor software to monitor, command, and control experiments via mobile devices. (3) Results: Cell viability results indicate that the newly designed compression bioreactor supports cell cultivation in a sterile environment without any contamination. The developed bioreactor software plots the experimental data of dynamic mechanical loading in a long-term manner, as well as stores them for further data processing. Following in vitro uniaxial compression conditioning of 3D in vitro cartilage models, chondrocyte cell migration was altered positively compared to static cultures. (4) Conclusion: The developed compression bioreactor can support the in vitro tissue model cultivation and monitor the experimental information with a low-cost controlling system and via mobile application. The highly customizable mold inside the cultivation chamber is a significant approach to solve the limited customization capability of the traditional bioreactors. Most importantly, the compression bioreactor prevents operator- and system-dependent variability between experiments by enabling a dynamic culture in a large volume for multiple numbers of in vitro tissue constructs.

scholarly journals Light Cross-Linkable Marine Collagen for Coaxial Printing of a 3D Model of Neuromuscular Junction Formation

Biomedicines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 16
Author(s):  
Borja Sanz ◽  
Ane Albillos Sanchez ◽  
Bonnie Tangey ◽  
Kerry Gilmore ◽  
Zhilian Yue ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Neuromuscular Junction ◽  
Disease Transmission ◽  
Low Cost ◽  
Attractive Alternative ◽  
Waste Products ◽  
Environmentally Sustainable ◽  
Zoonotic Disease Transmission ◽  
And Migration

Collagen is a major component of the extracellular matrix (ECM) that modulates cell adhesion, growth, and migration, and has been utilised in tissue engineering applications. However, the common terrestrial sources of collagen carry the risk of zoonotic disease transmission and there are religious barriers to the use of bovine and porcine products in many cultures. Marine based collagens offer an attractive alternative and have so far been under-utilized for use as biomaterials for tissue engineering. Marine collagen can be extracted from fish waste products, therefore industry by-products offer an economical and environmentally sustainable source of collagen. In a handful of studies, marine collagen has successfully been methacrylated to form collagen methacrylate (ColMA). Our work included the extraction, characterization and methacrylation of Red Snapper collagen, optimisation of conditions for neural cell seeding and encapsulation using the unmodified collagen, thermally cross-linked, and the methacrylated collagen with UV-induced cross-linking. Finally, the 3D co-axial printing of neural and skeletal muscle cell cultures as a model for neuromuscular junction (NMJ) formation was investigated. Overall, the results of this study show great potential for a novel NMJ in vitro 3D bioprinted model that, with further development, could provide a low-cost, customizable, scalable and quick-to-print platform for drug screening and to study neuromuscular junction physiology and pathogenesis.

scholarly journals Fabrication, Characterization and In Vitro Cytotoxicity of Mesoporous β-Tricalcium Phosphate Using the Spray Drying Method

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 252
Author(s):  
Henni Setia Ningsih ◽  
Leonhard Tannesia ◽  
Hsiang-Ho Chen ◽  
Shao-Ju Shih
Keyword(s):  
Spray Drying ◽  
Tricalcium Phosphate ◽  
Low Cost ◽  
In Vitro Cytotoxicity ◽  
Formation Mechanisms ◽  
Synthesis Methods ◽  
Average Pore ◽  
Calcination Temperatures ◽  
Future Demands

Mesoporous beta tricalcium phosphate (β-TCP) has recently attracted significant interest as an artificial bone tissue in orthopedics. However, a scalable process is required to meet future demands. Spray drying is one of the potential synthesis methods owing to its low cost and scalable production. In this study, various mesoporous β-TCP powders were calcined in the range of 800 to 1100 °C, with particle sizes ranging from ~0.3 to ~1.8 μm, specific surface areas from ~16 to ~64 m2/g, and average pore sizes of 3 nm. Except for the 800 °C calcined powder, the other β-TCP powders (calcination temperatures of 900, 1000, and 1100 °C) exhibited no cytotoxicity. These results indicate that spray-dried mesoporous β-TCP powders were obtained. Finally, the corresponding formation mechanisms are discussed.

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