To explore the clinical consequences and potential root causes of insulin pump-associated adverse events (AEs) reported in the Food and Drug Administration's Manufacturer and User Facility Device ...Experience (MAUDE) database.
Qualitative template analysis of narrative data in a 20% stratified random sample (
= 2429) of reported AEs that occurred during the first 6 months of 2020 involving five insulin pump models marketed at that time: (1) MiniMed™ 670G, (2) MiniMed™ 630G, (3) Omnipod
, (4) Omnipod DASH
, and (5) t:slim X2™.
Of the 2429 AEs, 92% included a clinical consequence in the narrative description, with critical hyperglycemia (i.e., blood glucose BG >400 mg/dL; 47%) and critical hypoglycemia (i.e., BG <54 mg/dL; 24%) being the most common consequence cited. Only 50% of the AE narratives included information to support the identification of a root cause. The most cited root cause informing remarks were issues with the pump or pod reservoir/cartridge (9%), the occurrence of an obstruction of flow alarm (8%), and problems with the infusion set or site (8%). Some clinical consequences and root cause informing remarks were cited more frequently in AE narratives involving specific insulin pump models, but manufacturer variability in the amount and type of information reported may have affected these findings.
Our findings show general themes found in insulin pump-associated AE that providers can use to raise patient awareness of potential risks associated with insulin pump use and develop strategies to prevent future AEs. Improvements in AE investigation and reporting processes are still necessary.
The incessant traffic of ions across cell membranes is controlled by two kinds of border guards: ion channels and ion pumps. Open channels let selected ions diffuse rapidly down electrical and ...concentration gradients, whereas ion pumps labour tirelessly to maintain the gradients by consuming energy to slowly move ions thermodynamically uphill. Because of the diametrically opposed tasks and the divergent speeds of channels and pumps, they have traditionally been viewed as completely different entities, as alike as chalk and cheese. But new structural and mechanistic information about both of these classes of molecular machines challenges this comfortable separation and forces its re-evaluation.
Peristaltic pumps have been put to use in various biomedical applications like devices for the transfer of body fluids as well as devices for controlled release of medication, including implantable ...infusion pumps. Out of the various components of a peristaltic pump, tubing is considered the most vulnerable part. This study focuses on the performance of Silicone micro-pump tubing used in such an implantable drug delivery device. Long-term implantable medical devices are expected to be operational for about 10 years. But experimental testing of the reliability of components under normal working speeds are time-consuming and thus delays the product development cycle. While simulating the conditions in the laboratory under accelerated speeds, the effect of increasing the speed must be accounted. In this study, the effect of accelerated speed and rotor material on pump tubing life is investigated. A test jig is developed which simulates the running conditions of the infusion pump for long-duration operation. Different rotor speeds and material configurations are investigated to obtain their effect on long-duration performance. Thermal effects on the roller junctions are studied and found that the Delrin silicone combination has twice the rise in junction temperature than the titanium silicone combination. The failure modes are inspected using microstructure analysis and the best configuration is identified.
Abstract When the pump turbine does variable speed operation, it can improve the operation efficiency in the turbine mode, and it can improve the automatic frequency adjustment efficiency in the pump ...mode. However, the hydraulic thrust will also change when the speed changes, and the magnitude of the hydraulic thrust is crucial for the safe and stable operation of the unit. The work of this paper is to analyze the changes of the axial hydraulic force and radial force with the change of the speed by numerical simulation method. It is found that the fluctuation of axial hydraulic thrust can reach about 34 t at 398.57rpm speed, 37 t at 412.16rpm speed and 21 t at 428.6rpm speed. the fluctuation of radial force can reach about 13.78 t, 14.4 t and 12.4 t. The purpose of this paper is to use the simulation results to understand the hydraulic thrust characteristics and ensure the stability of the unit to select the appropriate speed range, provide the basis for stable operation of the unit under design conditions.
High-speed axial piston pumps are the key components of electro-hydrostatic actuators (EHA). Pumps of this kind have been used in large civil aircraft like the Airbus A380. Preventing the tilting ...micro-motion of the rotating cylinder in an EHA pump is an important issue for reducing wear and prolonging their lifetime. Aiming to reduce the cylinder tilt behaviour, a laser surface texturing (LST) technique was applied to the steel valve plate, which is in contact with a brass cylinder. An experimental investigation was conducted on an EHA pump prototype running at 10,000 r/min and 28 MPa. The mechanical and volumetric efficiencies of the prototype equipped with the textured valve plate are improved by about 2.6% and 1.4%, respectively. Wear mechanisms of the tested components are analysed comprehensively to elucidate the cause for cylinder tilt behaviour and the functional mechanism of surface texture. The surface texture is found to increase efficiencies by reducing wear and the cylinder tilt angle. The cylinders are prone to tilt towards the high-pressure side, and the most severe wear of the valve plates does not occur on the contact regions near the cylinder outer edge on that side. Finally, implications for designing surface textures for the cylinder/valve plate interface are described.
•A laser surface textured valve plate was tested on an EHA pump at 10,000 r/min.•Surface texture improves the mechanical efficiency of the pump by about 2.6%.•Micro-dimples reduce wear and the cylinder tilt angle.•Contact regions near cylinder outer edge did not suffer the severest wear.•Implications for designing surface textures for this interface are described.
The efficiency requirements for hydraulic pumps applied in automatic transmissions in future generations of automobiles will increase continuously. In addition, the pumps must be able to cope with ...multiphase flows to a certain extent. Given this background, a balanced vane pump (BVP), an internal gear pump (IGP) and a three-dimensional geared tumbling multi chamber (TMC) pump are analyzed and compared by a computational fluid dynamics (CFD) approach with ANSYS CFX and TwinMesh. Furthermore, test bench measurements are conducted to obtain experimental data to validate the numerical results. The obtained numerical results show a reasonable agreement with the experimental data. In the first CFD setup, the conveying characteristics of the pumps with pure oil regarding volumetric efficiencies, cavitation onset and pressure ripple are compared. Both the IGP and the BVP show high volumetric efficiencies and low pressure ripples whereas the TMC shows a weaker performance regarding these objectives. In the second CFD setup, an oil-bubbly air multiphase flow with different inlet volume fractions (IGVF) is investigated. It can be shown that free air changes the pumping characteristics significantly by increasing pressure and mass flow ripple and diminishing the volumetric efficiency as well as the required driving torque. The compression ratios of the pumps appear to be an important parameter that determines how the multiphase flow is handled regarding pressure and mass flow ripple. Overall, the BVP and the IGP show both a similar strong performance with and without free air. In the current development state, the TMC pump shows an inferior performance because of its lower compression ratio and therefore needs further optimization.
Light-activated, ion-pumping rhodopsins are broadly distributed among many different bacteria and archaea inhabiting the photic zone of aquatic environments. Bacterial proton- or sodium-translocating ...rhodopsins can convert light energy into a chemiosmotic force that can be converted into cellular biochemical energy, and thus represent a widespread alternative form of photoheterotrophy. Here we report that the genome of the marine flavobacterium Nonlabens marinus S1-08 ᵀ encodes three different types of rhodopsins: Nonlabens marinus rhodopsin 1 (NM-R1), Nonlabens marinus rhodopsin 2 (NM-R2), and Nonlabens marinus rhodopsin 3 (NM-R3). Our functional analysis demonstrated that NM-R1 and NM-R2 are light-driven outward-translocating H ⁺ and Na ⁺ pumps, respectively. Functional analyses further revealed that the light-activated NM-R3 rhodopsin pumps Cl ⁻ ions into the cell, representing the first chloride-pumping rhodopsin uncovered in a marine bacterium. Phylogenetic analysis revealed that NM-R3 belongs to a distinct phylogenetic lineage quite distant from archaeal inward Cl ⁻-pumping rhodopsins like halorhodopsin, suggesting that different types of chloride-pumping rhodopsins have evolved independently within marine bacterial lineages. Taken together, our data suggest that similar to haloarchaea, a considerable variety of rhodopsin types with different ion specificities have evolved in marine bacteria, with individual marine strains containing as many as three functionally different rhodopsins.
Abstract Cavitation instabilities are caused by unsteady cavitation in the inducer in liquid rocket turbopumps. This phenomenon has a negative impact on pumps and must be suppressed. Our research ...group has proposed a method to suppress the instabilities by adding slits to the inducer blades, and previous studies was shown the effectiveness of this method. In this study, water experiments of inducers with slits at different locations were conducted. As a results, the vibration characteristics of cavitation in the slit inducers changed when the location of the slit was changed although the cavitation instabilities were successfully suppressed in all slit inducer. The visualized image of cylindrical surface of the axial flow pump was expanded into a two-dimensional plane to determine the time variation of the area of the tip leakage vortex cavitation generated in each blade. The suppression mechanism of cavitation instabilities in each slit location was discussed from the obtained unsteady image of cavity area in each blade in the slit inducers.
Introduction
Ventricular assist devices (VADs) are considered an effective treatment for patients with advanced heart failure, while complications associated with blood damage remain a burden. ...Structure design innovation has the potential to reduce hemolysis and improve hemocompatibility.
Methods
In this research, a novel mixed‐flow blood pump that integrates structural features of the axial and centrifugal VADs was proposed. The pump consists of an inducer, a mixed impeller supported by two ceramic pivot bearings, and a volute. The flow field and laminar viscous shear stress were analyzed by the in silico simulation. The hydraulic and hemolytic performance were evaluated in vitro by using a 3D printed pump.
Results
The flow field distribution showed that streamlines in the connection area were smoothly transitioned through structural integration and no irregular flow occurred in the entire flow channel. The axial blades work as a fluid accelerator (generating 18.56% of the energy), and the centrifugal blades provide the main pressure head. The proportion of fluid inside the pump exposed to low laminar viscous shear stress (<50 Pa) and high laminar viscous shear stress (>150 Pa) was 99.02% and 0.03%, respectively. The in vitro hemolysis test results showed that the NIH (Normalized Index of Hemolysis) value of the mixed pump is 0.0079 ± 0.0039 g/100 L (n = 6).
Conclusion
It can be concluded that the mixed flow structure is effective at improving hydraulic performance, eliminating flow disturbance, and minimizing shear stresses. This novel pump design is expected to provide a new direction for the development of next‐generation VADs.
A novel mixed‐flow blood pump that integrates structural features of the axial and centrifugal VADs was proposed. The hemodynamic behaviors analyzed in silico showed that streamlines were smoothly transitioned through structural integration and no irregular flow occurred. Furthermore, the hemolytic results evaluated in vitro by using a 3D printed pump showed that the NIH (Normalized Index of Hemolysis) value is 0.0079 ± 0.0039 g/100 L (n = 6).
•A novel air source heat pump system which using multi-evaporator to defrost each other was proposed;•Full-scale contrast experiments in 5 conditions were carried;•A general model to evaluate heat ...pump’s performance was proposed;•Stable water temperature and low energy consumption were obtained by the system proposed;•Continuous heating during the defrosting period was achieved.
Air source heat pumps (ASHPs) are prone to frost when heating in a low-temperature and high-humidity environment, which deteriorates the heating performance of the unit. In this study, a new multi-evaporator mutual defrosting (MEMD) system was proposed to overcome the disadvantages of traditional defrosting methods: intermittent heating and inefficient defrosting. To validate the performance of the proposed defrosting technology, comparative tests were conducted in various outdoor environmental conditions. The experimental results showed that the MEMD system could continuously heat water during the defrosting period. In five experimental conditions, the MEMD system exhibited a lower water temperature drop range (2.1–2.8 °C) than that of a traditional reverse-cycle defrosting (RCD) system (6.0–7.3 °C). Due to the effective utilization of heat production during the heating period, the effective heat power (qe) of the unit increased by 0.7–1.4 kW, and the heat loss coefficient (HLC) of frosting and defrosting increased by an average of 6 % in the five experimental conditions, effectively reducing the heating capacity loss of the unit caused by defrosting. While defrosting, the MEMD system was able to utilize the remaining evaporators to absorb heat from the air and then deliver it to the defrosting evaporator. The equivalent defrosting energy efficiency (COPd) of the MEMD system was 17.5 % greater than that of the RCD system on average. During the heating and defrosting cycle, the energy saved when defrosting could increase the cycle coefficient of performance (CCOP) of heating by 3.7 %.
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