scholarly journals Clinical evaluation of the Admiral 1.35m2 hollow-fibre membrane oxygenator

Perfusion ◽  
2008 ◽  
Vol 23 (1) ◽  
pp. 33-38 ◽  
Author(s):  
R Issitt ◽  
T Cumberland ◽  
A Clements ◽  
J Mulholland
Keyword(s):  
Surface Area ◽  
Clinical Performance ◽  
Artery Bypass ◽  
Hollow Fibre ◽  
Current Standard ◽  
Small Surface ◽  
Pressure Drops ◽  
Standard Data ◽  
Priming Volume ◽  
And Performance

This prospective study was designed to evaluate the fundamental clinical performance of a new, small surface area oxygenator. Data were collected from twenty patients undergoing first-time coronary artery bypass grafting using this device. This study focuses on how the reduction of surface area and prime volume affects the essential function of the oxygenator in terms of oxygenation efficiency, heat transference, membrane pressure drops, haemolysis and safety. Oxygenation efficiency was deemed to be well within acceptable margins, even at high flows, over a temperature range of 32-36°C. Heat-exchanger performance was assessed by recording the heater/chiller water temperature compared to retrospective data from a current standard oxygenator. Heater/chiller water temperatures were on average 0.3°C higher with the small surface oxygenator than the standard data. The air handling of the device was excellent and extremely safe. Haemolysis, measured as plasma free haemoglobin, did not increase during bypass (p>0.05). This new oxygenator offers a reduced surface area and priming volume while still ensuring an acceptable safety reserve and performance.

A clinical evaluation of platelet function, haemolysis and oxygen transfer during cardiopulmonary bypass comparing the Quantum HF-6700 to the HF-5700 hollow fibre membrane oxygenator

Perfusion ◽  
2000 ◽  
Vol 15 (6) ◽  
pp. 479-484 ◽  
Author(s):  
A O Chukwuemeka ◽  
M RJ Turtle ◽  
U H Trivedi ◽  
G E Venn ◽  
D J Chambers
Keyword(s):  
Cardiopulmonary Bypass ◽  
Platelet Function ◽  
Clinical Evaluation ◽  
Oxygen Transfer ◽  
Artery Bypass ◽  
Membrane Surface ◽  
Platelet Activating Factor ◽  
Hollow Fibre ◽  
Priming Volume ◽  
First Time

The continued improvement of oxygenators is an important aspect of patient safety during cardiopulmonary bypass (CPB). The purpose of this study was to compare the Bard William Harvey HF-5700 oxygenator to the upgraded Bard Quantum HF-6700, which has recently been introduced into clinical practice. No clinical evaluation of this device has been published to date. The two oxygenators differ principally in that the Quantum has a smaller priming volume, achieved at the expense of a smaller membrane surface area which could result in sub-optimal gas exchange characteristics, increased haemolysis and increased platelet dysfunction during CPB. Twenty adult patients undergoing elective, first time coronary artery bypass grafting (CABG) were randomly assigned either to the HF-5700 ( n=10) or to the HF-6700 ( n=10) group. One patient underwent mitral valve repair in addition to CABG and was excluded from further study. There were no statistically significant differences in either preoperative or operative parameters between the two groups. Samples were obtained at the start of CPB, at 30 min, 60 min, at the end of CPB and at 1 h following termination of CPB. No significant differences between the two groups were found in oxygen transfer, haemolysis (plasma haptoglobin levels) or platelet function (a novel platelet activating factor (PAF)-induced platelet activation test) at any of the time points during CPB. It was concluded that the Quantum HF-6700 matches the HF-5700 for the parameters studied, whilst having the advantage of requiring a smaller priming volume.

Performance and maneuverability of three species of teleostean fishes

2001 ◽  
Vol 79 (10) ◽  
pp. 1866-1877 ◽  
Author(s):  
Paul W Webb ◽  
Antonia Gardiner Fairchild
Keyword(s):  
Surface Area ◽  
Distribution Patterns ◽  
Body Depth ◽  
Small Surface ◽  
Pectoral Fins ◽  
Functional Capabilities ◽  
Goldfish Carassius Auratus ◽  
And Performance ◽  
Median Fins ◽  
Pterophyllum Scalare

Whole-animal behavior and performance are assembled from functional capabilities that are dependent on morphology, such as body form and fin-distribution patterns. We compared hovering, median and paired fin (MPF), body and caudal fin (BCF), and burst-and-coast gaits and maneuvers permitted within these gaits, turning, backward swimming, and braking for three species: goldfish, Carassius auratus, silver dollar, Metynnis hypsauchen, and angelfish, Pterophyllum scalare. Goldfish have a fusiform body with a relatively small surface area and depth. Silver dollars and angelfish had larger areas and depths. The smaller surface area was expected to be associated with greater use and higher speeds in BCF swimming behaviors for goldfish but little support was found. Larger body depth was expected to be associated with higher turning rates and maneuverability of silver dollars versus goldfish, but data were again equivocal. Body depth may be more important in defense than in locomotion. Goldfish and silver dollars have ventral paired fins. Angelfish have more derived lateral pectoral fins, anterior pelvic fins, and larger median fins. This fin pattern was expected to be associated with greater use of MPF behaviors at higher speeds, and with greater maneuverability. Support for this expectation was found, but there were sufficient exceptions to indicate that other factors were important.

scholarly journals Is Periodontitis a Predictor for an Adverse Outcome in Patients Undergoing Coronary Artery Bypass Grafting? A Pilot Study

2021 ◽  
Vol 10 (4) ◽  
pp. 818
Author(s):  
Stefan Reichert ◽  
Susanne Schulz ◽  
Lisa Friebe ◽  
Michael Kohnert ◽  
Julia Grollmitz ◽  
...  
Keyword(s):  
Risk Factor ◽  
Coronary Artery ◽  
Coronary Artery Bypass Grafting ◽  
Surface Area ◽  
Coronary Artery Bypass ◽  
Artery Bypass ◽  
Bypass Grafting ◽  
Artery Bypass Grafting ◽  
Cabg Surgery

Periodontitis is a risk factor for atherosclerosis and coronary vascular disease (CVD). This research evaluated the relationship between periodontal conditions and postoperative outcome in patients who underwent coronary artery bypass grafting (CABG). A total of 101 patients with CVD (age 69 years, 88.1% males) and the necessity of CABG surgery were included. Periodontal diagnosis was made according to the guidelines of the Centers for Disease Control and Prevention (CDC, 2007). Additionally, periodontal epithelial surface area (PESA) and periodontal inflamed surface area (PISA) were determined. Multivariate survival analyses were carried out after a one-year follow-up period with Cox regression. All study subjects suffered from periodontitis (28.7% moderate, 71.3% severe). During the follow-up period, 14 patients (13.9%) experienced a new cardiovascular event (11 with angina pectoris, 2 with cardiac decompensation, and 1 with cardiac death). Severe periodontitis was not significant associated with the incidence of new events (adjusted hazard ratio, HR = 2.6; p = 0.199). Other risk factors for new events were pre-existing peripheral arterial disease (adjusted HR = 4.8, p = 0.030) and a history of myocardial infarction (HR = 6.1, p = 0.002). Periodontitis was not found to be an independent risk factor for the incidence of new cardiovascular events after CABG surgery.

THE FEASIBILITY OF KAOLIN AS MAIN MATERIAL FOR LOW COST POROUS CERAMIC HOLLOW FIBRE MEMBRANE PREPARED USING COMBINED PHASE INVERSION AND SINTERING TECHNIQUE

2017 ◽  
Vol 79 (1-2) ◽  
Author(s):  
Siti Khadijah Hubadillah ◽  
Mohd Hafiz Dzarfan Othman ◽  
A. F. Ismail ◽  
Mukhlis A. Rahman ◽  
Juhana Jaafar
Keyword(s):  
Phase Inversion ◽  
Low Cost ◽  
Pure Water ◽  
Porous Ceramic ◽  
Water Flux ◽  
Hollow Fibre ◽  
Hollow Fibre Membrane ◽  
Fibre Membrane ◽  
Pure Water Flux ◽  
And Performance

Ceramic hollow fibre membrane (CHFM) demonstrated superior characteristics and performance in any separation application. The only problem associated with this kind of technology is the high cost. In order to effectively fabricate and produce low cost porous CHFM, a series of CHFMs made of kaolin were fabricated via combined phase inversion and sintering technique. The CHFMs from kaolin named as kaolin hollow fibre membranes (KHFMs) were studied at different kaolin contents of 35 wt.%, 37.5 wt.% and 40 wt.% sintered at 1200ºC. The result indicated that by varying kaolin contents, different morphologies were obtained due to changes in the viscosity of ceramic suspension containing kaolin. The optimum kaolin content for KHFM was identified. It was found that KHFM prepared at 37.5 wt% has a mechanical strength and pure water flux of A and B respectively.  

Periodically Converging-Diverging Tubes and Their Turbulent Heat Transfer, Pressure Drop, Fluid Flow, and Enhancement Characteristics

1984 ◽  
Vol 106 (1) ◽  
pp. 55-63 ◽  
Author(s):  
P. Souza Mendes ◽  
E. M. Sparrow
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Surface Area ◽  
Equal Mass ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Transfer Coefficients ◽  
Pressure Drops ◽  
Heat Transfer Coefficients ◽  
Friction Factors

A comprehensive experimental study was performed to determine entrance region and fully developed heat transfer coefficients, pressure distributions and friction factors, and patterns of fluid flow in periodically converging and diverging tubes. The investigated tubes consisted of a succession of alternately converging and diverging conical sections (i.e., modules) placed end to end. Systematic variations were made in the Reynolds number, the taper angle of the converging and diverging modules, and the module aspect ratio. Flow visualizations were performed using the oil-lampblack technique. A performance analysis comparing periodic tubes and conventional straight tubes was made using the experimentally determined heat transfer coefficients and friction factors as input. For equal mass flow rate and equal transfer surface area, there are large enhancements of the heat transfer coefficient for periodic tubes, with accompanying large pressure drops. For equal pumping power and equal transfer surface area, enhancements in the 30–60 percent range were encountered. These findings indicate that periodic converging-diverging tubes possess favorable enhancement characteristics.

Comparative physiology of insect renal function

1981 ◽  
Vol 241 (5) ◽  
pp. R241-R257 ◽  
Author(s):  
J. Phillips
Keyword(s):  
Surface Area ◽  
Total Surface Area ◽  
Malpighian Tubules ◽  
Thick Ascending Limb ◽  
Small Surface ◽  
Multiplier System ◽  
Wide Range ◽  
Glomerular Filtrate ◽  
Unit Body Weight ◽  
Anion Transfer

Transport mechanisms and their control in various segments of insect excretory systems are reviewed and compared to those of vertebrate nephrons, exocrine glands, and hindguts. Formation of the primary urine in most insect Malpighian tubules (MT) is by isosmotic secretion, which is driven by an apical cation (K+) pump rather than by Na+-K+-ATPase. Unlike the glomerular filtrate of vertebrates, insect MT fluid is very different from the blood in composition, often having very high K+-to-Na+ ratios, and urine-to-plasma values much less than unity for most other solutes. The total surface area of insect MT is some 20 times that of vertebrate glomeruli per unit body weight. Secretion of MT fluid is regulated by neuropeptides over a wide range of rats, similar to glomerular filtration rate values for many vertebrate kidneys. Several secretory mechanisms for selected solutes are probably common to insect and vertebrate tubules. Unlike vertebrates, insects usually reabsorb most of the filtered water, ions, and metabolites in the rectum, which has a small surface area relative to the MT. The rectum is also where ionic and osmotic composition of the excreta is finally adjusted, under the control of neuropeptide hormones. In the rectum, insect excreta can become as hyperosmotic as mammalian urine, even though a countercurrent multiplier system is not present. Active transport of Cl- predominates in both locust rectum and the thick ascending limb of Henle's loop, but the characteristics of the anion transfer process are quite different in these two epithelia.xs

scholarly journals Study on Relationship Between Age and Coffee Preference: Application to Specialty Coffee Association Brewing Control Chart

2019 ◽  
Vol 35 (2) ◽  
pp. 131-139
Author(s):  
Joy Xue
Keyword(s):  
Control Chart ◽  
Total Dissolved Solids ◽  
Taste Preferences ◽  
Current Standard ◽  
Standard Data ◽  
The Past ◽  
Specialty Coffee ◽  
Age Range ◽  
Larger Sample ◽  
Coffee Brewing

The Specialty Coffee Association Brewing Control chart has been used for the past 50 years, and is intended to assist the coffee brewer by stating the brew ratio and TDS (total dissolved solids) value needed to brew an “ideal” cup of coffee. Since coffee is a common and popular beverage that is consumed among populations ranging from children to elders, the objective of this study was to find out whether taste preferences in coffee vary based on age and whether these preferences match the current brewing control chart standard. Data collected in this study was based on a taste test with 32 total participants selected randomly. Of these participants, 10 fell into the 10-19 years old age range, 5 in the 20-29 range, 4 in the 30-39 range, 7 in the 40-49 range, and 6 in the 50-59 range. Based on the data from these respondents, no obvious trend between age range and coffee preference was observed; but, this is subject to change with larger sample sizes.Overall taste preferences, however, do generally fit the current standard ideal range on the coffee brewing control chart.

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