Effect of fiber structure on dialysate flow profile and hollow-fiber hemodialyzer reliability: CT perfusion study

2008 ◽  
Vol 31 (11) ◽  
pp. 944-950 ◽  
Author(s):  
J. C. Kim ◽  
J. H. Kim ◽  
H.-C. Kim ◽  
E. Kang ◽  
K. G. Kim ◽  
...  
Keyword(s):  
Hollow Fiber ◽  
Fiber Type ◽  
Mean Transit Time ◽  
Intraclass Correlation ◽  
Flow Profile ◽  
Fiber Structure ◽  
Dialysate Flow ◽  
Flow Profiles ◽  
Perfusion Studies ◽  
Straight Fiber

Background Uniform dialysate distributions in hollow-fiber hemodialyzers facilitate effective solute removal, and the fiber structure inside hemodialyzers plays a significant role in determining dialysate flow distribution and dialysis efficiency. The authors analyzed the effects of undulated fibers on dialysate flow profiles and hemodialyzer reliability using a perfusion CT technique. Method Using a multi-detector row CT unit, perfusion studies were performed on two different types of hemodialyzers: (A) straight fiber configuration; (B) undulated fiber configuration (wavy-shaped fibers). Deconvolution theory was used for image processing to derive dialysate flows, dialysate volumes, and mean transit time distributions. Three-dimensional perfusion maps for the two types of hemodialyzers were reconstructed using high resolution images and these parameters were compared at hemodialyzer midsections. Results Dialysate maldistributions were observed in both types of hemodialyzer. However, dialysate flow distributions were more uniform in the undulated-fiber hemodialyzer, whereas more complex flow distributions developed in straight-fiber hemodialyzer. Reliability as determined using intraclass correlation coefficients was markedly higher for the hemodialyzer containing undulated fiber (0.968 vs. 0.496 for type A and type B, respectively). Conclusions The undulated-fiber type was found to have more uniform, consistent dialysate flow profiles. It is believed that this type of hemodialyzer will be found helpful for measurement and prescription of the delivered hemodialysis dose due to its better consistency.

Dialysate Pressure Isobars in a Hollow‐Fiber Dialyzer Determined from Magnetic Resonance Imaging and Numerical Simulation of Dialysate Flow

1998 ◽  
Vol 22 (10) ◽  
pp. 907-909 ◽  
Author(s):  
Toshiaki Osuga ◽  
Takayuki Obata ◽  
Hiroo Ikehira ◽  
Shuji Tanada ◽  
Yasuhito Sasaki ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Numerical Simulation ◽  
Magnetic Resonance ◽  
Hollow Fiber ◽  
Resonance Imaging ◽  
Dialysate Flow

scholarly journals Theoretical Comparison of McKibben-Type Artificial Muscle and Novel Straight-Fiber-Type Artificial Muscle

2011 ◽  
Vol 5 (4) ◽  
pp. 544-550 ◽  
Author(s):  
Hiroki Tomori ◽  
◽  
Taro Nakamura
Keyword(s):  
Steady State ◽  
Dynamic Characteristic ◽  
Fiber Type ◽  
Human Life ◽  
Artificial Muscle ◽  
Artificial Muscles ◽  
Contraction Rate ◽  
Theoretical Comparison ◽  
Straight Fiber ◽  
Force Characteristics

Robots have entered human life, and closer relationships are being formed between humans and robots. It is desirable that these robots be flexible and lightweight. With this as our goal, we have developed an artificial muscle actuator using straight-fiber-type artificial muscles derived from the McKibben-type muscles, which have excellent contraction rate and force characteristics. In this study, we compared the steady state and dynamic characteristic of straightfiber-type and McKibben-type muscles and verified the usefulness of straight-fiber-type muscles.

scholarly journals A New Hollow-Fiber Adsorbent Material for Removing Arsenic from Groundwater

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Sang Hyun Lee ◽  
Sung Su Kim
Keyword(s):  
Mechanical Strength ◽  
Optimal Condition ◽  
Hollow Fiber ◽  
Fiber Type ◽  
Adsorption Efficiency ◽  
Arsenic Adsorption ◽  
Extrusion Speed ◽  
Polymeric Solution

To optimize the arsenic-adsorption efficiency and the mechanical strength of a hollow-fiber-type adsorbent, the optimal condition of polymeric solution was determined as 32 wt.% TiO2 and 17 wt.% polymer. A micropore-sponge form was developed at the slurry-extrusion speed of 2.500 ml/min and the internal coagulant-solution-extrusion speed of 1.250 ml/min, and the arsenic-adsorption efficiency improved. Given the result under conditions in natural groundwater containing various ions, the hollow-fiber-type adsorbent can be applied to real groundwater purification processes.

Evaluation of the mass transfer rate using computer simulation in a three-dimensional interwoven hollow fiber-type bioartificial liver

2018 ◽  
Vol 40 (11-12) ◽  
pp. 1567-1578 ◽  
Author(s):  
Ryoichi Sakiyama ◽  
Hiroyuki Hamada ◽  
Brandon Blau ◽  
Nora Freyer ◽  
Katrin Zeilinger ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Computer Simulation ◽  
Hollow Fiber ◽  
Transfer Rate ◽  
Fiber Type ◽  
Mass Transfer Rate ◽  
Three Dimensional ◽  
Bioartificial Liver

Comparative Analysis of Two Volumetrical Ultrafiltration Monitors for Hemodialysis

1986 ◽  
Vol 9 (3) ◽  
pp. 163-166
Author(s):  
J.H.M. Berden ◽  
J.M.P. Wokke ◽  
R.A.P. Koene
Keyword(s):  
Comparative Analysis ◽  
Correlation Coefficient ◽  
Hollow Fiber ◽  
Clinical Setting ◽  
Parallel Flow ◽  
The Other ◽  
Dialysis Modality ◽  
Volumetric Measurement ◽  
Dialysate Flow ◽  
Regression Correlation

Controlled ultrafiltration (UF) during hemodialysis may prevent dialysis associated hypotension. A prerequisite for controlled ultrafiltration is an accurate measurement of ultrafiltration. Volumetric measurement is the best currently available method for this purpose. In this study we compared in a clinical setting two volumetric ultrafiltration monitors (UFM): one device constructed in our hospital using oval flowmeters (UFM-N) and the other using electromagnetic flow transducers (UFM-G: UFM 10-2, Gambro Lund Sweden). The UF measurements of both UFM's were compared with UF calculated from bedscales weight monitoring and standard scales determinations. During dual needle hemodialysis (n = 8) with a hollow fiber dialyzer the accuracy of the UFM-N was 91% and that of the UFM-G 97%. During dual needle dialysis with a parallel flow dialyzer the UFM-N appeared to be more sensitive for pulsatile changes in the dialysate flow due to the greater compliance of this type of dialyzer. The accuracy of the UFM-N in this setting was 80%, while that of the UFM-G was 87% (n = 11). During single needle dialysis with a parallel flow dialyzer (n = 14) only the UFM-G was tested and it measured UF with an accuracy of 92%. Finally the UFM-G can control UF actively by adjusting the TMP to obtain a given UF rate. The accuracy of the UFM-G in this setting was 94%, and the lineair regression correlation coefficient between planned UF and actually obtained UF was 0.974 (n - 61). In conclusion volumetric monitoring of UF is accurate and reliable, but its accuracy is dependent on the type of dialyzer used. The UFM-G proved to be useful in every dialysis modality tested, while the UFM-N can be used in dual-needle dialysis using hollow fiber dialyzers.

scholarly journals A Steady-State Mass Transfer Model of Removing CPAs From Cryopreserved Blood With Hollow Fiber Modules

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Weiping Ding ◽  
Xiaoming Zhou ◽  
Shelly Heimfeld ◽  
Jo-Anna Reems ◽  
Dayong Gao
Keyword(s):  
Blood Flow ◽  
Steady State ◽  
Hollow Fiber ◽  
State Model ◽  
Transfer Model ◽  
Unsteady State ◽  
Flow Rates ◽  
Dialysate Flow ◽  
Steady State Model ◽  
Mass Transfers

Hollow fiber modules are commonly used to conveniently and efficiently remove cryoprotective agents (CPAs) from cryopreserved cell suspensions. In this paper, a steady-state model coupling mass transfers across cell and hollow fiber membranes is theoretically developed to evaluate the removal of CPAs from cryopreserved blood using hollow fiber modules. This steady-state model complements the unsteady-state model, which was presented in our previous study. The steady-state model, unlike the unsteady-state model, can be used to evaluate the effect of ultrafiltration flow rates on the clearance of CPAs. The steady-state model is validated by experimental results, and then is compared with the unsteady-state model. Using the steady-state model, the effects of ultrafiltration flow rates, NaCl concentrations in dialysate, blood flow rates and dialysate flow rates on CPA concentration variation and cell volume response are investigated in detail. According to the simulative results, the osmotic damage of red blood cells can easily be reduced by increasing ultrafiltration flow rates, increasing NaCl concentrations in dialysate, increasing blood flow rates, or decreasing dialysate flow rates.

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