Series and parallel integration of flow regulators for precise and multiple-output fluid delivery

2021 ◽  
Vol 332 ◽  
pp. 113160
Author(s):  
Fengtao Jiang ◽  
Nan Xiang
Keyword(s):  
Fluid Delivery ◽  
Parallel Integration

Safety Management of Dialysis Fluid in Japan: Important Duties and Responsibilities of Clinical Engineers

2021 ◽  
pp. 1-6
Author(s):  
Masanori Shibata
Keyword(s):  
Renal Failure ◽  
Safety Management ◽  
Standard Procedure ◽  
Medical Personnel ◽  
Maintenance Hemodialysis ◽  
Dialysis Fluid ◽  
Fluid Delivery ◽  
Technical Ability ◽  
Number Of Patients ◽  
Clinical Engineers

Dialysis therapy is the predominant choice for renal failure in Japan, and almost 30% of the patients with renal failure have been treated for 10 years or more. Dialysis became the standard procedure to treat renal failure nationwide in the 1980s. However, at that time, managing the increased number of patients on maintenance hemodialysis as well as operating and maintaining the newly developed advanced medical technologies at extensive numbers of clinical sites proved problematic. To help address this, the clinical engineer system was established in 1987 and certain aspects of the clinical engineers’ role remain unique to Japan today. For the last 30 years, clinical engineers have worked as frontline medical personnel not only operating dialysis-related devices but also placing their hands directly on patients when providing care, routinely performing puncture, and administering drugs through the blood circuit under physicians’ instructions. As part of their work, they crucially maintain the use of central dialysis fluid delivery systems (CDDSs) – also unique to Japan – which prepare and deliver a large quantity of dialysis fluid through a central circuit to individual dialysis consoles. CDDSs are widely used because they effectively alleviated the early confusion at clinical sites caused by the rapidly increasing hemodialysis population and the serious shortage in medical personnel. Moreover, clinical engineers alone have the technical ability to provide safe dialysis fluids adjusted to strict standards at clinical sites. In this review article, we focus on the crucial roles that clinical engineers have in maintaining the safety of dialysis-related medical devices and the preparation and delivery of dialysis fluid at many dialysis facilities across the country.

Nonosmotic release of vasopressin and renal aquaporins in impaired urinary dilution in hypothyroidism

2005 ◽  
Vol 289 (4) ◽  
pp. F672-F678 ◽  
Author(s):  
Yung-Chang Chen ◽  
Melissa A. Cadnapaphornchai ◽  
Jianhui Yang ◽  
Sandra N. Summer ◽  
Sandor Falk ◽  
...  
Keyword(s):  
Protein Expression ◽  
Renal Cortex ◽  
Free Water ◽  
Urine Osmolality ◽  
Protein Abundance ◽  
Oral Gavage ◽  
Water Excretion ◽  
Urinary Osmolality ◽  
Water Load ◽  
Fluid Delivery

The purpose of this study was to examine protein expression of renal aquaporins (AQP) and ion transporters in hypothyroid (HT) rats in response to an oral water load compared with controls (CTL) and HT rats replaced with l-thyroxine (HT+T). Hypothyroidism was induced by aminotriazole administration for 10 wk. Body weight, water intake, urine output, solute and urea excretion, and serum and urine osmolality were comparable among the three groups at the conclusion of the 10-wk treatment period. One hour after oral gavage of water (50 ml/kg body wt), HT rats demonstrated significantly less water excretion, higher minimal urinary osmolality, and decreased serum osmolality compared with CTL and HT+T rats. Despite the hyposmolality, plasma vasopressin concentration was elevated in HT rats. These findings in HT rats were associated with an increase in protein abundance of renal cortex AQP1 and inner medulla AQP2. AQP3, AQP4, and the Na-K-2Cl cotransporter were also increased. Moreover, 1 h following the oral water load, HT rats demonstrated a significant increase in the membrane-to-vesicle fraction of AQP2 by Western blot analysis. The defect in urinary dilution in HT rats was reversed by the V2 vasopressin antagonist OPC-31260. In conclusion, impaired urinary dilution in HT rats is primarily compatible with the nonosmotic release of vasopressin and increased protein expression of renal AQP2. The impairment of maximal solute-free water excretion in HT rats, however, appears also to involve diminished distal fluid delivery.

Embedded Two-Phase Cooling of High Flux Electronics via Micro-Enabled Surfaces and Fluid Delivery Systems (FEEDS)

2015 ◽  
Author(s):  
Raphael Mandel ◽  
Serguei Dessiatoun ◽  
Patrick McCluskey ◽  
Michael Ohadi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Pressure Drop ◽  
Saturation Temperature ◽  
Absolute Pressure ◽  
High Flux ◽  
Vapor Quality ◽  
Two Phase ◽  
Fluid Delivery ◽  
Future Work

This work presents the experimental design and testing of a two-phase, embedded manifold-microchannel cooler for cooling of high flux electronics. The ultimate goal of this work is to achieve 0.025 cm2-K/W thermal resistance at 1 kW/cm2 heat flux and evaporator exit vapor qualities at or exceeding 90% at less than 10% absolute pressure drop. While the ultimate goal is to obtain a working two-phase embedded cooler, the system was first tested in single-phase mode to validate system performance via comparison of experimentally measured heat transfer coefficient and pressure drop to the values predicted by CFD simulations. Upon validation, the system was tested in two phase mode using R245fa at 30°C saturation temperature and achieved in excess of 1 kW/cm2 heat flux at 45% vapor quality. Future work will focus on increasing the exit vapor quality as well as use of SiC for the heat transfer surface upon completion of current experiments with Si.

Micropuncture analysis of single-nephron function in NHE3-deficient mice

1999 ◽  
Vol 277 (3) ◽  
pp. F447-F453 ◽  
Author(s):  
John N. Lorenz ◽  
Patrick J. Schultheis ◽  
Timothy Traynor ◽  
Gary E. Shull ◽  
Jürgen Schnermann
Keyword(s):  
Proximal Tubule ◽  
Filtration Rate ◽  
Distal Tubule ◽  
Transport Processes ◽  
Tubuloglomerular Feedback ◽  
Thick Ascending Limb ◽  
Fluid Reabsorption ◽  
Fluid Delivery ◽  
Single Nephron ◽  
Flow Pressure

The Na/H exchanger isoform 3 (NHE3) is expressed in the proximal tubule and thick ascending limb and contributes to the reabsorption of fluid and electrolytes in these segments. The contribution of NHE3 to fluid reabsorption was assessed by micropuncture in homozygous ( Nhe3 −/−) and heterozygous ( Nhe3 +/−) knockout mice, and in their wild-type (WT, Nhe3 +/+) littermates. Arterial pressure was lower in the Nhe3 −/−mice (89 ± 6 mmHg) compared with Nhe3 +/+ (118 ± 4) and Nhe3 +/−(108 ± 5). Collections from proximal and distal tubules demonstrated that proximal fluid reabsorption was blunted in both Nhe3 +/− and Nhe3 −/−mice (WT, 4.2 ± 0.3; Nhe3 +/−, 3.4 ± 0.2; and Nhe3 −/−, 2.6 ± 0.3 nl/min; P < 0.05). However, distal delivery of fluid was not different among the three groups of mice (WT, 3.3 ± 0.4 nl/min; Nhe3 +/−, 3.3 ± 0.2 nl/min; and Nhe3 −/−, 3.0 ± 0.4 nl/min; P < 0.05). In Nhe3 −/−mice, this compensation was largely attributable to decreased single-nephron glomerular filtration rate (SNGFR): 10.7 ± 0.9 nl/min in the Nhe3 +/+ vs. 6.6 ± 0.8 nl/min in the Nhe3 −/−, measured distally. Proximal-distal SNGFR differences in Nhe3 −/−mice indicated that much of the decrease in SNGFR was due to activation of tubuloglomerular feedback (TGF), and measurements of stop-flow pressure confirmed that TGF is intact in Nhe3 −/−animals. In contrast to Nhe3 −/−mice, normalization of early distal flow rate in Nhe3 +/−mice was not related to decreased SNGFR (9.9 ± 0.7 nl/min), but rather, to increased fluid reabsorption in the loop segment ( Nhe3 +/+, 2.6 ± 0.2; Nhe3 +/−, 3.6 ± 0.5 nl/min). We conclude that NHE3 is a major Na/H exchanger isoform mediating Na+ and fluid reabsorption in the proximal tubule. In animals with NHE3 deficiency, normalization of fluid delivery to the distal tubule is achieved through alterations in filtration rate and/or downstream transport processes.

Vascularized Materials: Grids of Channels and Trees Matched Canopy to Canopy

2006 ◽  
Author(s):  
Sunwoo Kim ◽  
Kuan-Min Wang ◽  
Sylvie Lorente ◽  
Adrian Bejan
Keyword(s):  
Fluid Flows ◽  
Decisive Role ◽  
Network Configuration ◽  
Fundamental Study ◽  
Pressure Drops ◽  
Stream Flows ◽  
Fluid Delivery ◽  
Optimal Flow ◽  
Global Performance ◽  
And Function

This is a fundamental study of how to discover the optimal flow architecture to vascularize a volume so that fluid flow and function (e.g. cooling, sensing, maintenance, repair, healing) reaches every point of the material. The presentation is made by discussing flow architectures that deliver healing fluid to all the crack sites that may occur randomly through the material. Two concepts are explored. In the first, a grid of interconnected channels is built into the material, and is filled with pressurized healing fluid. When a crack forms, the pressure drops at the crack site and fluid flows from the grid into the crack. The objective is to discover the network configuration that is capable of delivering fluid to all the cracks the fastest. It is shown that the optimization of the ratio of channel diameters cuts in half the time of fluid delivery to the crack. In the second concept, one stream flows steadily through the material and bathes it volumetrically. The stream enters through one port, and distributes itself as a river delta through the volume. Later the stream reconstitutes itself as a river basin before exiting the volume through one point. This second concept is equivalent to matching two trees canopy to canopy. It is shown that the choice of tree-tree configuration has a decisive role on the global performance of the vascularized composite.

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