Closed-Loop Insulin Delivery Versus Sensor-Augmented Pump Therapy in Older Adults With Type 1 Diabetes (ORACL): A Randomized, Crossover Trial

Objective <p>To assess the efficacy and safety of closed-loop insulin delivery compared with sensor-augmented pump therapy among older adults with type 1 diabetes.</p> <h2>Research Design and Methods</h2> <p>This open-label randomized (1:1), crossover trial compared 4 months of closed-loop versus sensor-augmented pump therapy. Eligible adults were aged ≥60 years, with type 1 diabetes (duration ≥10 years), using an insulin pump. The primary outcome was continuous glucose monitoring (CGM) time in range <a>(TIR; 3.9–10.0 mmol/L</a>).</p> <h2>Results</h2> <p>Thirty participants (mean age 67 years [SD 5]; median type 1 diabetes duration 38 years [IQR 20–47]) were randomized, <i>n</i>=15 to each sequence; all completed the trial. The mean TIR was 75.2% (6.3) during the closed-loop stage and 69.0% (9.1) during the sensor-augmented pump stage (difference 6.2 percentage points [95% CI 4.4, 8.0]; <i>P</i> <0.0001). All prespecified CGM metrics favored closed loop over sensor-augmented pump; benefits were greatest overnight. Closed loop reduced CGM time <3.9 mmol/L during 24 h/day by 0.5 percentage points (0.3, 1.1; <i>P</i> = 0.0005) and overnight by 0.8 percentage points (0.4, 1.1; <i>P</i> <0.0001) compared with sensor-augmented pump. There was no significant difference in HbA_1c between closed-loop versus sensor-augmented pump stages (7.3% [7.1–7.5] | 56 mmol/mol [54–59] versus 7.5% [7.1–7.9] | 59 mmol/mol [54–62], respectively; <i>P</i> = 0.13). Three severe hypoglycemia events occurred during the closed-loop stage and two occurred during the sensor-augmented pump stage; no hypoglycemic events required hospitalization. One episode of diabetic ketoacidosis occurred during the sensor-augmented pump stage; no serious adverse events occurred during the closed-loop stage.</p> <h2>Conclusion</h2> <p>Closed-loop therapy is an effective treatment option for older adults with long duration type 1 diabetes and no safety issues were identified. These older adults had higher TIR accompanied by less time below range during closed-loop than sensor-augmented pump therapy. Of particular clinical importance, closed loop reduced the time spent in hypoglycemic range overnight. </p>

Closed-Loop Insulin Delivery Versus Sensor-Augmented Pump Therapy in Older Adults With Type 1 Diabetes (ORACL): A Randomized, Crossover Trial

Objective <p>To assess the efficacy and safety of closed-loop insulin delivery compared with sensor-augmented pump therapy among older adults with type 1 diabetes.</p> <h2>Research Design and Methods</h2> <p>This open-label randomized (1:1), crossover trial compared 4 months of closed-loop versus sensor-augmented pump therapy. Eligible adults were aged ≥60 years, with type 1 diabetes (duration ≥10 years), using an insulin pump. The primary outcome was continuous glucose monitoring (CGM) time in range <a>(TIR; 3.9–10.0 mmol/L</a>).</p> <h2>Results</h2> <p>Thirty participants (mean age 67 years [SD 5]; median type 1 diabetes duration 38 years [IQR 20–47]) were randomized, <i>n</i>=15 to each sequence; all completed the trial. The mean TIR was 75.2% (6.3) during the closed-loop stage and 69.0% (9.1) during the sensor-augmented pump stage (difference 6.2 percentage points [95% CI 4.4, 8.0]; <i>P</i> <0.0001). All prespecified CGM metrics favored closed loop over sensor-augmented pump; benefits were greatest overnight. Closed loop reduced CGM time <3.9 mmol/L during 24 h/day by 0.5 percentage points (0.3, 1.1; <i>P</i> = 0.0005) and overnight by 0.8 percentage points (0.4, 1.1; <i>P</i> <0.0001) compared with sensor-augmented pump. There was no significant difference in HbA_1c between closed-loop versus sensor-augmented pump stages (7.3% [7.1–7.5] | 56 mmol/mol [54–59] versus 7.5% [7.1–7.9] | 59 mmol/mol [54–62], respectively; <i>P</i> = 0.13). Three severe hypoglycemia events occurred during the closed-loop stage and two occurred during the sensor-augmented pump stage; no hypoglycemic events required hospitalization. One episode of diabetic ketoacidosis occurred during the sensor-augmented pump stage; no serious adverse events occurred during the closed-loop stage.</p> <h2>Conclusion</h2> <p>Closed-loop therapy is an effective treatment option for older adults with long duration type 1 diabetes and no safety issues were identified. These older adults had higher TIR accompanied by less time below range during closed-loop than sensor-augmented pump therapy. Of particular clinical importance, closed loop reduced the time spent in hypoglycemic range overnight. </p>

CFD-DEM Simulation of Backflow Blockage of Deep-Sea Multistage Pump

The multistage centrifugal pump is the critical component of mineral resources lifting in deep-sea mining. The reflux of nodules in the lifting pipe caused by the emergency pump stop can easily cause the pump to clog. In this paper, coupled Computational Fluid Dynamics and Discrete Element Method (CFD-DEM co-simulations) are used to clarify the solid-liquid two-phase flow in two-stage centrifugal pumps under different particle sizes (10–20, 20–30, 30–40, 40–50 mm) with constant particle concentration. The movement and accumulation behaviour of particles in different flow fields (pipeline to pump, the first to the second pump stage) is investigated. Meanwhile, the effect of particle size and particle reflux velocity on the blockage of the flow channel in the pump was investigated. Particle accumulation in the pump was observed to determine the key factors affecting the pump’s reflux capacity. The residual mass of particles in the pump at different particle sizes was counted. Simultaneously, the percentage of residual mass of 10–20 mm particles in the pump was compared between the experiment and the simulation with an acceptable tolerance of within 10%. In addition, pressure changes in the blockage-prone section were also investigated. A comparison between experiments and simulations verifies the consistency of the trend on the pump inlet pressure when clogged with 50 mm particles. It was found that larger particles in the range of 10–30 mm can better ensure the pump’s reflux performance.

Particle Distribution and Motion in Six-Stage Centrifugal Pump by Means of Slurry Experiment and CFD-DEM Simulation

Six-stage centrifugal pumps are used in deep-sea mining lifting systems and are required to convey slurry containing coarse particles. A six-stage centrifugal pump suitable for operation in a natural mining system was manufactured. High-flow and full-scaled slurry conveying experiments at a 5% and 9% volume concentration of particles was carried out at a large modified test site with artificial nodules. CFD-DEM simulations were carried out to obtain slurry transport characteristic curves, particle transport and distribution characteristics, where the simulation method was validated by the experiment data. A clarified two-stage pump can be used instead of a multi-stage pump for simplified simulation calculations with acceptable accuracy. Local agglomeration of particles caused by backflow was found at the outlet of the diffuser, and such agglomeration decreased with increasing flow rates. It was found that particles are transported non-uniformly, particles transport in diffusers in strands. Particles are transported in a pulse-like mode within the pump, with the latter stage showing similar particle characteristics to those transported in the previous pump stage.

Numerical Investigation of Axial Thrust Control in a Multistage Canned-Motor Pump With Pump-Out-Vanes

Axial thrust is one of the critical factors that affect the pump’s continuously operating reliability. Among all the available methods for axial thrust controlling, Pump Out Vanes (POVs) are an easy and effective way. Different from a single-stage pump with a scroll, an in-line multistage pump will have a leakage flow channel from the return channel. With this leakage channel, the working environment of the POVs will be significantly different from a single-stage pump. In this paper, the first stage of a multistage pump with both POVs and casing ribs (vortex breakers) is studied by CFD simulation to evaluate their effect on the axial thrust, pump stage performance, and the internal leakage flow. Because of the similar POV working environment in the multistage pump, the conclusion from one stage can be generalized for the rest stages. In this study, 5 models with different POV outer radius and height are simulated in Ansys Fluent with k-ε turbulence model and transient rotor-stator sliding mesh method. The results show that POVs with suitable geometry can provide good axial thrust control over a wide pump operating range while the stage efficiency can be strongly affected due to the increased turbulence and interstage leakage flow, which is contradicting some previous researcher’s conclusion based on the study of a single-stage centrifugal pump.

On the Method of Calculating Diffusion Vacuum Pump Stage Pumping Parameters

At present, steam jet vacuum pumps are widely used in various fields of science and technology due to a number of advantages, e.g., reliability, relative simplicity of design, and manufacturability, over other pumping means. The paper analyzes the existing mathematical models of working processes, methods for calculating the pumping parameters of steam-jet vacuum pumps. The problem of improving these methods, which are used in the design, is still urgent. The study attempts to further develop the models in order to increase their practical significance for the pumps design: in particular, the processes of pumping by the first stages of a diffusion pump are considered, since it is they that determine the efficiency of the pump as a whole. Analytical dependences for calculating the main pumping parameters of widely used diffusion vacuum pumps are presented. The obtained equations are a certain clarifying correction of the known provisions on this topic. Findings of research are of practical importance for the design of modern steam-jet vacuum pumps

Tricuspid Atresia With Truncus Arteriosus: Off-Pump Stage I Palliation

Coexistence of tricuspid atresia and truncus arteriosus (common arterial trunk) is an extremely rare combination of anomalies and requires staged palliation. Initial palliation involves disconnection of the pulmonary arteries from the common trunk and creation of a systemic-to-pulmonary artery shunt. This has generally been accomplished with the use of cardiopulmonary bypass. We describe a technique of off-pump palliation using the common trunk and a modified Blalock-Taussig shunt as sources of pulmonary blood flow at various stages of reconstruction. The child has recovered well and has undergone second-stage palliation with bilateral bidirectional superior cavopulmonary anastomoses at one year of age.

Complex model description and main capacitor sizing for the cross-coupled charge pump synthesis process

This paper presents a dynamic part of the pump stage model of the cross-coupled charge pump. The complex model has been used for both the estimation of the N-stage pump properties in a wide range of the input parameters and derivation of equations for synthesis process, as the main capacitor sizing, which is also mentioned in the article. Dynamic part of the model (pump stage capacitances) is determined from Ward’s capacitance piece-wise model through the BSIM MOSFET model equations. Main capacitor and load capacitor sizing are based on the time response characteristics fulfilling the system behavior in time. Guideline on the MOS transistor sizing as the nonlinear main pump capacitor and specification of the diode transistor for the design process are also clarified. The characteristics of the proposed circuit have been verified in the professional design environment Mentor graphics and analysis algorithm based on the state-space description of the inner complex model was programmed in Maple SW. The main benefit is to offer the alternative way of the charge pump synthesis by using the complex model and symbolic description of all formulae to find the required pump parameters without long-time simulation process.