Platelet Aggregometry and Shape Change Measurement by Laser Light in Small Samples

1979 ◽  
Author(s):  
P. Blasberg ◽  
L.J. Wurzinper
Keyword(s):  
Hollow Fiber Membrane ◽  
Shape Change ◽  
Scattered Light ◽  
Transmitted Light ◽  
Small Samples ◽  
Change Measurement ◽  
Platelet Aggregometry ◽  
Space Angle ◽  
Flow Through ◽  
Set Up

A technique is presented to measure platelet aggregation (PA) and platelet shape change (PSC) with high accuracy in small samples (100 ul) using a turbidimetric method wich a He-Ne-Laser as light source. Both, transmitted and scattered light, Is measured by two independent light sensitive elements. Transmitted light is detected by a photodiode with a sensitive area of 1 mm2 covering a space angle of Ω= 0.004 sterad. Scattered light is detected by a photoelement surrounding the photodiode which covers a space angle of U-1.4 sterad. Ar, electronic set up forms a signal, which is proportional to the ratio scattered light/scattered light + transmitted light.The output voltage is linearly correlated to the turbidity of the suspension. The whole set up is employed with three different types of cuvettes.1. A cuvette where through a semipermeable hollow fiber membrane different drugs can diffuse into the platelet suspensions avoiding any stirring of the sample ()2. A flow through cuvette to measure the extent of PA in PRP samples.3. A couette type platelet aggregometer.

A DC Voltage Driven Flow-Through Electroporation Microchip

2009 ◽  
Vol 60-61 ◽  
pp. 44-48
Author(s):  
Qiao Le Zhao ◽  
Yu Cheng Lin ◽  
Qin Gan Huang
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Shape Change ◽  
Low Cost ◽  
Strength Distribution ◽  
Time Span ◽  
Dc Voltage ◽  
Flow Through ◽  
Set Up ◽  
Field Strengths

Differing with the traditional way to perform electroporation (EP) by using the DC electrical pulse, this paper proposes a new EP system by applying continuous DC voltages to generate proper EP electric field strengths utilizing the shape change of the channel. The fabrication of chip and set-up of system are clearly described and simulations also carried out utilizing CFD-ACE to study the electric field strength distribution and the time span when fluid passes through different electric field strengths. The fabrication of the proposed EP system is quite simple and low-cost.

Hollow fiber membrane applied for Sasirangan wastewater desalination integrated with photocatalysis and pervaporation set-up

2021 ◽  
Author(s):  
Isnasyauqiah ◽  
Muthia Elma ◽  
Eggy A. Pradana ◽  
Muhammad D. Ul-haq ◽  
Erdina L.A. Rampun ◽  
...  
Keyword(s):  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Fiber Membrane ◽  
Set Up

Free Zone Electrophoresis of Clotting Factors

1979 ◽  
Author(s):  
T. Cartwright ◽  
C.H. Dickerson ◽  
D.E.G. Austen
Keyword(s):  
Factor Viii ◽  
Total Yield ◽  
Solid Matrix ◽  
Clotting Factors ◽  
Free Zone ◽  
Zone Electrophoresis ◽  
Flow Apparatus ◽  
Electrophoresis System ◽  
Flow Through ◽  
Set Up

A free-zone electrophoresis system is used for rapid production of substantially purified factor VIII from either citrated plasma or from a factor VIII Concentrate of intermediate purety. Using concentrate, a total yield of 43% of clotting activity is obtained with fibrinogen reduced to approximately 30% of its starting level. Protein level is reduced to 20% of the original value. Using plasma, the albumin, factor VIII and fibrinogen were all separated from factor VIII. In these experiments, factor-VIII-related antigen migrates with the coagulant factor VIII illustrating that both have similar mobilities equivalent to that of an alpha-globulin, or else that they are connected together. The particular advantage of this separation is that it is carried out in a continuous flow apparatus in liquid buffer with no solid matrix and that once the apparatus is set up, material can flow through the machine at a rate of 5 mls/min being continuously separated. The main problem and area for further study is that of concentrating the relatively dilute fractions without undue loss.

Direct Activation of Platelets by Tissue Factor Is Amplified by FVIIa and Potentiated by Serotonin: Influence of Shear Rate.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3906-3906
Author(s):  
Maribel Diaz-Ricart ◽  
Irene Lopez-Vilchez ◽  
Ana M. Galan ◽  
Raul Tonda ◽  
Antonio Ordinas ◽  
...  
Keyword(s):  
Shear Rate ◽  
Tissue Factor ◽  
Shape Change ◽  
Critical Role ◽  
Atherosclerotic Plaques ◽  
Second Phase ◽  
Direct Role ◽  
Reversible Aggregation ◽  
Platelet Aggregometry ◽  
Ischemic Complications

Abstract Although exposure of tissue factor (TF) at sites of disrupted atherosclerotic plaques plays a critical role in platelet-triggered ischemic complications, a direct interaction of TF with platelets has not been yet demonstrated. We have investigated the effects of TF on platelets under different shear rate conditions. Exposure of isolated washed platelets to TF derived from human placenta resulted in reversible aggregation (35-50% max at 1 min) using standard platelet aggregometry. This response was αIIb-β3 dependent and occurred in the presence of residual concentrations of calcium. TF-induced reversible aggregation was enhanced and made irreversible to 90–100% by the addition of FVIIa (5μg/ml). This second phase of activation was blocked by the presence of serine-protease inhibitors. A combination of ultrastructural and flow cytometry studies revealed that although TF induced shape change and moderate expression of P-selectin an ANV positive phospholipids, internal contraction and full platelet degranulation only occurred after addition of FVIIa. All these transformations occurred together with tyrosine phosphorylation of proteins. Platelets adhered, spread and aggregated onto synthetic membranes coated exclusively with TF that had been exposed to circulating blood. Addition of FVIIa caused a 50% enhancement on platelet interactions and a two-fold increase in fibrin deposition. Serotonin enhanced overall TF induced platelet interactions under the different experimental approaches. A selective serotonin reuptake inhibitor (citalopram) reduced the intensity and extent of the effects of TF in the two experimental settings used in our investigations. Our results are consistent with a direct role of TF on platelet-triggered ischemic complications. We demonstrate that a lipidated from of TF activates isolated platelets in suspension. In studies conducted with flowing whole blood we show that TF firmly attached to a surface acts itself as an adhesive substrate, and promotes formation of aggregates. These TF-platelet interactions are enhanced through serotoninergic mechanism and markedly potentiated in the presence of FVIIa. The possible synergism between FVIIa and serotoninergic mechanisms may well contribute to the development of severe ischemic complications triggered on ruptured atherosclerotic plaques.

scholarly journals Graphitization of Small Carbonate Samples for Paleoceanographic Research at the Godwin Radiocarbon Laboratory, University of Cambridge

Radiocarbon ◽  
2016 ◽  
Vol 58 (1) ◽  
pp. 89-97 ◽  
Author(s):  
E Freeman ◽  
L C Skinner ◽  
R Reimer ◽  
A Scrivner ◽  
S Fallon
Keyword(s):  
Iron Powder ◽  
Hydrogen Reduction ◽  
Ion Beam ◽  
Small Sample ◽  
Small Samples ◽  
University Of Cambridge ◽  
National University ◽  
Set Up ◽  
The University ◽  
Selection Of

AbstractA new radiocarbon preparation facility was set up in 2010 at the Godwin Laboratory for Palaeoclimate Research, at the University of Cambridge. Samples are graphitized via hydrogen reduction on an iron powder catalyst before being sent to the Chrono Centre, Belfast, or the Australian National University for accelerator mass spectrometry (AMS) analysis. The experimental setup and procedure have recently been developed to investigate the potential for running small samples of foraminiferal carbonate. By analyzing background values of samples ranging from 0.04 to 0.6 mg C along with similar sized secondary standards, the setup and experimental procedures were optimized for small samples. “Background” modern 14C contamination has been minimized through careful selection of iron powder, and graphitization has been optimized through the use of “small volume” reactors, allowing samples containing as little as 0.08 mg C to be graphitized and accurately dated. Graphitization efficiency/fractionation is found not to be the main limitation on the analysis of samples smaller than 0.07 mg C, which rather depends primarily on AMS ion beam optics, suggesting further improvements in small sample analysis might yet be achieved with our methodology.

Electroosmotic Flow Through Porous Materials

2014 ◽  
Author(s):  
Rakesh Saini ◽  
Matthew Kenny ◽  
Dominik P. J. Barz
Keyword(s):  
Porous Materials ◽  
Electroosmotic Flow ◽  
Capillary Flow ◽  
Cost Effective ◽  
Packed Bed ◽  
Flow Rates ◽  
Bed Porosity ◽  
Flow Through ◽  
Set Up ◽  
Air Liquid Interface

Electroosmotic flow can be employed in many microfluidic systems. Especially, highly porous materials are suitable since they generate significant flow rates and pressures. In the current research, we employ electroosmosis experiments using a relatively simple and cost-effective set-up including different sets of sintered packed beds of borosilicate micro spheres having a wider range of porosities. Various experiments are performed with varying applied electric field, and packed bed porosity. The flow rates are measured by tracking the air/liquid interface in a capillary which is connected to the packed bed. A mathematical model of the setup reveals the influence of the capillary flow on the flow rate of the electroosmotic flow.

Analysis of microsamples with an FT-Raman microscope

1992 ◽  
Vol 50 (2) ◽  
pp. 1504-1505
Author(s):  
N.T. Kawai ◽  
J. Sawatski ◽  
C. Lehner
Keyword(s):  
Scattered Light ◽  
High Sensitivity ◽  
Optical Microscope ◽  
Small Samples ◽  
Ir Detector ◽  
Raman Spectrometer ◽  
Near Ir ◽  
Ft Raman Spectroscopy ◽  
Visible Wavelengths ◽  
Ft Raman

Rapid developments in near-IR filter and detector technology have resulted in FT-Raman spectroscopy emerging as a powerful technique in both research and analytical laboratories. The more recent advances in FT-Raman instrumentation now emphasize the optimization of different sampling accessories, including microsampling techniques. Microscopes attached to conventional Raman spectrometers operating at visible wavelengths have already proven to be applicable to many problems of chemical analysis. However, the optimized combination of an optical microscope and a near-IR FT-Raman spectrometer currently enables the analysis of very small samples which would normally fluoresce with visible excitation. Such samples include polymer fibers and thin films, dyes on fabrics, and small biological samples.In FT-Raman microscopy, the microscope is coupled to the near-IR FT-Raman spectrometer via fiber optic cables. These cables transfer the Nd:YAG laser beam from the spectrometer to the microscope, and channel the scattered light back again to be modulated by the interferometer and measured by the high sensitivity near-IR detector.

Pumping O2 with no N2: An Overview of Hollow Fiber Membrane Oxygenators with Integrated Arterial Filters

2020 ◽  
Vol 20 (1) ◽  
pp. 78-85 ◽  
Author(s):  
Anxin Liu ◽  
Zhiquan Sun ◽  
Qier Liu ◽  
Ning Zhu ◽  
Shigang Wang
Keyword(s):  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Experimental Studies ◽  
Circulation System ◽  
Fiber Membrane ◽  
Priming Volume ◽  
Membrane Oxygenators ◽  
Set Up

The advancement of cardiac surgery benefits from the continual technological progress of cardiopulmonary bypass (CPB). Every improvement in the CPB technology requires further clinical and laboratory tests to prove its safety and effectiveness before it can be widely used in clinical practice. In order to reduce the priming volume and eliminate a separate arterial filter in the CPB circuit, several manufacturers developed novel hollow-fiber membrane oxygenators with integrated arterial filters (IAF). Clinical and experimental studies demonstrated that an oxygenator with IAF could reduce total priming volume, blood donor exposure and gaseous microemboli delivery to the patient. It can be easily set up and managed, simplifying the CPB circuit without sacrificing safety. An oxygenator with IAF is expected to be more beneficial to the patients with low body weight and when using a minimized extracorporeal circulation system. The aim of this review manuscript was to discuss briefly the concept of integration, the current oxygenators with IAF, and the in-vitro / in-vivo performance of the oxygenators with IAF.

Liquid Transport Properties in Sub-Micron Channel Flows

2001 ◽  
Author(s):  
K. Johan A. Westin ◽  
Kenneth S. Breuer ◽  
Chang-Hwan Choi ◽  
Peter Huang ◽  
Zhiqiang Cao ◽  
...  
Keyword(s):  
Flow Rate ◽  
Low Flow ◽  
Slip Boundary Conditions ◽  
Liquid Transport ◽  
Flow Rates ◽  
Slip Boundary ◽  
Laminar Channel Flow ◽  
Flow Through ◽  
Set Up ◽  
Good Agreement

Abstract An experimental set-up for pressure driven liquid flow through microchannels have been designed and tested. The flow rate is determined by tracking the free liquid surface in a precision bore hole using a laser distance meter. Measurements of the flow rate through silicon microchannels with a height of less than 0.9 μm show good results for Newtonian fluids (silicon oil, ethanol) at flow rates as low as 0.2 nl/s. The experimental results are also in very good agreement with predictions based on laminar channel flow using no-slip boundary conditions, indicating that standard macroscopic assumptions are still valid for these fluids under these conditions. However, experiments with aqueous solutions show anomalies in the form of unexpectedly low flow rates and time dependent variations. Possible explanations to these observations are discussed.

scholarly journals An Experimental Study of Membrane Contactor Modules for Recovering Cyanide through a Gas Membrane Process

Membranes ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 105
Author(s):  
Michelle Quilaqueo ◽  
Gabriel Seriche ◽  
Sicely Valetto ◽  
Lorena Barros ◽  
Simón Díaz-Quezada ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Gold Mining ◽  
Hollow Fiber Membrane ◽  
Scaling Up ◽  
Membrane Contactor ◽  
Operational Conditions ◽  
Set Up ◽  
Valuable Compounds ◽  
Module Performance ◽  
The Impact

Cyanide is one of the main reagents used in gold mining that can be recovered to reduce operational costs. Gas membrane technology is an attractive method for intensifying both the stripping and absorption processes of valuable compounds, such as cyanide. However, scaling-up this technology from laboratory to industry is an unsolved challenge because it requires the improvement of the experimental methodologies that replicate lab-scale results at a larger scale. With this purpose in mind, this study compares the performance of three different hollow fiber membrane contactor modules (1.7 × 5.5 Mini Module, 1.7 × 10 Mini Module, and 2.5 × 8 Extra Flow). These are used for recovering cyanide from aqueous solutions at laboratory scale, using identical operational conditions. For each experimental set-up, mass-transfer correlations at the ranges of feed flows assayed were determined. The modules with the smallest and largest area of mass transfer reached similar cyanide recoveries (>95% at 60 min), which demonstrate the impact of module configuration on their operating performance. The results obtained here are limited for scaling-up the membrane module performance only because operating modules with the largest area results in a low Re number. This fact limits the extrapolation of results from the mass-transfer correlation.

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