scholarly journals Sampling Artifacts from Conductive Silicone Tubing

2009 ◽  
Vol 43 (9) ◽  
pp. 855-865 ◽  
Author(s):  
Michael T. Timko ◽  
Zhenhong Yu ◽  
Jesse Kroll ◽  
John T. Jayne ◽  
Douglas R. Worsnop ◽  
...  
Keyword(s):  
Silicone Tubing ◽  
Sampling Artifacts

scholarly journals TIME-INTEGRATED COLLECTION OF CO2 FOR 14C ANALYSIS FROM SOILS

Radiocarbon ◽  
2021 ◽  
pp. 1-17
Author(s):  
Shawn Pedron ◽  
X Xu ◽  
J C Walker ◽  
J C Ferguson ◽  
R G Jespersen ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Molecular Sieve ◽  
Emission Sources ◽  
Soil C ◽  
Silicone Tubing ◽  
2Nd Generation ◽  
C Cycle ◽  
Uptake Rates ◽  
Two Generations ◽  
Cleaning Procedures

ABSTRACT We developed a passive sampler for time-integrated collection and radiocarbon (14C) analysis of soil respiration, a major flux in the global C cycle. It consists of a permanent access well that controls the CO2 uptake rate and an exchangeable molecular sieve CO2 trap. We tested how access well dimensions and environmental conditions affect collected CO2, and optimized cleaning procedures to minimize 14CO2 memory. We also deployed two generations of the sampler in Arctic tundra for up to two years, collecting CO2 over periods of 3 days–2 months, while monitoring soil temperature, volumetric water content, and CO2 concentration. The sampler collects CO2 at a rate proportional to the length of a silicone tubing inlet (7–26 µg CO2-C day-1·m Si-1). With constant sampler dimensions in the field, CO2 recovery is best explained by soil temperature. We retrieved 0.1–5.3 mg C from the 1st and 0.6–13 mg C from the 2nd generation samplers, equivalent to uptake rates of 2–215 (n=17) and 10–247 µg CO2-C day-1 (n=20), respectively. The method blank is 8 ± 6 µg C (mean ± sd, n=8), with a radiocarbon content (fraction modern) ranging from 0.5875–0.6013 (n=2). The sampler enables more continuous investigations of soil C emission sources and is suitable for Arctic environments.

scholarly journals Using a roller pump for establishing extra-corporal membrane oxygenation (ECMO) – technical considerations for times of crisis

Perfusion ◽  
2021 ◽  
pp. 026765912199618
Author(s):  
Mirko Kaluza ◽  
Benjamin May ◽  
Torsten Doenst
Keyword(s):  
Flow Characteristics ◽  
Centrifugal Pumps ◽  
Roller Pump ◽  
Silicone Tubing ◽  
Heart Lung Machine ◽  
Surface Irregularities ◽  
Set Up ◽  
Flow Detection ◽  
Silicon Tubing

Objective: The COVID-19 pandemic requires thinking about alternatives to establish ECMO when often-limited hardware resources are exhausted. Heart-lung-machines may potentially be used for ECMO but contain roller pumps as compared to centrifugal pumps in ECMO-circuits. We here tested roller pumps as rescue pump for ECMO-establishment. Methods: We set up in vitro circuits on roller pumps from C5 heart-lung-machine with 5 l/minutes flow. In two series, we placed either PVC or silicon tubing for an ECMO circuit into the roller pump. We assessed the mechanical stress on the tubing (aiming to run the pump for at least 1 week), measured the temperature increase generated by the friction and assessed flow characteristics and its measurement in simulated situations resembling tube kinking and suction. Results: The roller pumps led to expected and unexpected adverse events. PVC tubing burst between 36 and 78 hours, while silicon tubing lasted for at least 7 days. At 7 days, the silicone tubing showed significant signs of roller pump wear visible on the outside. The inside, however, was free of surface irregularities. Using these tubings in a roller pump led to a remarkable increase in circuit temperature (PVC: +12.0°C, silicone +2.9°C). Kinking or suction on the device caused the expected dramatic flow reduction (as assessed by direct measurement) while the roller pump display continued to show the preset flow. The roller pump is therefore not able to reliably determine the true flow rate. Conclusion: Roller pumps with silicone tubing but not PVC tubing may be used for running ECMO circuits. Silicone tubing may endure the roller pump shear forces for up to 1 week. Thus, repeated tubing repositioning may be a solution. Circuit heating and substantial limitations in flow detection should increase attention if clinical use in situations of crisis is considered.

Preservative loss from silicone tubing during filling processes

2017 ◽  
Vol 112 ◽  
pp. 109-118 ◽  
Author(s):  
Verena Saller ◽  
Julia Matilainen ◽  
Christian Rothkopf ◽  
Daniel Serafin ◽  
Karoline Bechtold- Peters ◽  
...  
Keyword(s):  
Silicone Tubing

scholarly journals Impact of satellite viewing swath width on global and regional aerosol optical thickness statistics and trends

2013 ◽  
Vol 6 (6) ◽  
pp. 10117-10163 ◽  
Author(s):  
P. R. Colarco ◽  
R. A. Kahn ◽  
L. A. Remer ◽  
R. C. Levy
Keyword(s):  
Optical Thickness ◽  
Statistical Significance ◽  
Sampling Strategy ◽  
Aerosol Optical Thickness ◽  
Mean Values ◽  
Sampling Artifacts ◽  
Aerosol Loading ◽  
Decadal Scale ◽  
Along Track ◽  
The Impact

Abstract. We use the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite aerosol optical thickness (AOT) product to assess the impact of reduced swath width on global and regional AOT statistics and trends. Ten different sampling strategies are employed, in which the full MODIS dataset is sub-sampled with various narrow-swath (~400–800 km) and curtain-like (~10 km) along-track configurations. Although view-angle artifacts in the MODIS AOT retrieval confound direct comparisons between averages derived from different sub-samples, careful analysis shows that with many portions of the Earth essentially unobserved, the AOT statistics of these sub-samples exhibit significant regional and seasonal biases. These AOT spatial sampling artifacts comprise up to 60% of the full-swath AOT value under moderate aerosol loading, and can be as large as 0.1 in some regions under high aerosol loading. Compared to full-swath observations, narrower swaths exhibit a reduced ability to detect AOT trends with statistical significance, and for curtain-like sampling we do not find any statistically significant decadal-scale trends at all. An across-track sampling strategy obviates the MODIS view angle artifact, and its mean AOT converges to the full-swath mean values for sufficiently coarse spatial and temporal aggregation. Nevertheless, across-track sampling has significant seasonal-regional sampling artifacts, leading to biases comparable to the curtain-like along-track sampling, lacks sufficient coverage to assign statistical significance to aerosol trends, and is not achievable with an actual narrow-swath or curtain-like instrument. These results suggest that future aerosol satellite missions having significantly less than full-swath viewing are unlikely to sample the true AOT distribution well enough to determine decadal-scale trends or to obtain the statistics needed to reduce uncertainty in aerosol direct forcing of climate.

Silicone Tubing Used in Intubating the Lacrimal System

Ophthalmology ◽  
1984 ◽  
Vol 91 (8) ◽  
pp. 963-965 ◽  
Author(s):  
S. Rutherford ◽  
J.S. Crawford ◽  
J.J. Hurwitz
Keyword(s):  
Silicone Tubing ◽  
Lacrimal System

Subcutaneous reaction to silicone in ventriculoperitoneal shunts

1974 ◽  
Vol 41 (3) ◽  
pp. 367-371 ◽  
Author(s):  
Oscar Sugar ◽  
Orville T. Bailey
Keyword(s):  
Cerebrospinal Fluid ◽  
Connective Tissue ◽  
Fibrous Connective Tissue ◽  
Subcutaneous Implantation ◽  
Content Type ◽  
Ventriculoperitoneal Shunts ◽  
Silicone Tubing ◽  
Connective Tissue Sheath ◽  
Fine Print

✓Silicone tubing (Silastic) used for ventriculoperitoneal shunts induces a fibrous connective tissue sheath around the tubing in children and adults. Two children examined 8 and 3 years after subcutaneous implantation showed a complete tube of dense fibrous connective tissue around the silicone tubing. The reaction was entirely quiescent. These tubes of connective tissue were apparently capable of conveying cerebrospinal fluid for some months after the silicone tubing was disconnected from the pump or pulled out of the abdomen.

Sampling Artifacts in Quantitative Schlieren

2019 ◽  
Author(s):  
Todd A. Hay ◽  
John Valdez ◽  
Charles E. Tinney ◽  
Mark Hamilton ◽  
Christophe Schram
Keyword(s):  
Sampling Artifacts

scholarly journals Hemodynamic energy during pulsatile extracorporeal circulation using flexible and rigid arterial tubing: a reassessment

Perfusion ◽  
2018 ◽  
Vol 34 (4) ◽  
pp. 297-302
Author(s):  
Anke Dürr ◽  
Andreas Kunert ◽  
Günter Albrecht ◽  
Andreas Liebold ◽  
Markus Hoenicka
Keyword(s):  
Cardiac Surgery ◽  
Extracorporeal Circulation ◽  
Pulsatile Flow ◽  
Organ Perfusion ◽  
Pressure Data ◽  
High Compliance ◽  
Energy Equivalent ◽  
Silicone Tubing ◽  
Mock Circulation ◽  
Pulsatile Perfusion

Introduction: Pulsatile extracorporeal circulation may improve organ perfusion during cardiac surgery. Some minimally invasive extracorporeal circulation (MiECC) systems allow pulsatile perfusion. The present study investigated the influence of arterial tubing compliance on hemodynamic energy transfer into the patient. Methods: Aortic models with adult human geometry were perfused in a mock circulation. A MiECC system was connected using either high-compliance silicone tubing or standard kit tubing. Energy equivalent pressure (EEP) and surplus hemodynamic energy (SHE) were computed from flow and pressure data. Aortic models with physiological and sub-physiological compliance were tested to assess the influence of the pseudo-patient. Results: Non-pulsatile flow did not generate SHE. SHE during pulsatile flow in the compliant aortic model was significantly higher with kit tubing compared to silicone tubing. Maximum SHE was achieved at 1.6 L/min with kit tubing (7.7% of mean arterial pressure) and with silicone tubing (4.9%). Using the low-compliance aortic model, SHE with kit tubing reached a higher maximum of 14.2% at 1.8 L/min compared to silicone tubing (11.8% at 1.5 L/min). Conclusions: Flexible arterial tubing did not preserve more hemodynamic energy from a pulsatile pump compared to standard kit tubing in a model of adult extracorporeal circulation. The pseudo-patient’s compliance significantly affected the properties of the mock circulation.

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