scholarly journals Standardized technique of water permeability measurement for biomedical applications

2018 ◽  
Vol 4 (1) ◽  
pp. 633-636
Author(s):  
Swen Grossmann ◽  
Stefan Siewert ◽  
Robert Ott ◽  
Klaus-Peter Schmitz ◽  
Stefanie Kohse ◽  
...  
Keyword(s):  
Measurement Technique ◽  
Medical Devices ◽  
Water Permeability ◽  
Measurement Techniques ◽  
Test Sample ◽  
Hydraulic Pressure ◽  
Key Factor ◽  
Flow Through ◽  
Standardized Measurement ◽  
Nanofiber Membranes

AbstractStandardized methods and measures are ubiquitous in biomedical engineering and a key factor for the successful development and certification of novel biomaterials, implants or other medical devices. Hence, the development of standardized measurement techniques, which can be applied to nearly every material and device is of crucial importance. Within the current work, we introduce a method to evaluate the water permeability according to ISO/FDIS 7198. The setup was designed to determine the volumetric flow through a test sample for a given hydraulic pressure. One key feature is the effortless replacement of the chamber containing the test sample. The measurement technique can thus be applied to a variety of materials and medical devices. To demonstrate the functionality of the setup we fabricated nanofiber membranes using the process of electrospinning. Nonwovens with comparable thickness and varying morphology were analyzed with regard to water permeability. In particular the different fiber diameters as well as the modified inter-fiber distances result in large deviations of the water permeability. Furthermore, there are hints for a rearrangement of the nanofibers due to the applied hydraulic pressure. The developed measurement technique provides a powerful tool for the standardized quantification of the water permeability and can be applied to a variety of biomaterials and medical devices.

scholarly journals Standardized method for the measurement of Grabb’s line and clival-canal angle

2017 ◽  
Vol 20 (4) ◽  
pp. 352-356 ◽  
Author(s):  
Jonathan E. Martin ◽  
Markus Bookland ◽  
Douglas Moote ◽  
Catherine Cebulla
Keyword(s):  
Measurement Technique ◽  
Clinical Decision Making ◽  
Measurement Techniques ◽  
Intraclass Correlation ◽  
Clinical Decision ◽  
Radiographic Measurement ◽  
Pediatric Radiologist ◽  
Intrarater Reliability ◽  
Measurement Protocol ◽  
Standardized Measurement

OBJECTIVEGrabb’s line—the perpendicular distance from the basion-C2 line (pB-C2)—is a widely used radiographic measurement with significant clinical implications in patients with a complex Chiari malformation. Rigorous demonstration of the reproducibility of this measurement has not previously been reported. The authors report a standardized measurement technique with excellent inter- and intrarater reliability on T1-weighted sagittal MRI.METHODSThe authors developed a standardized measurement technique that included specifications of midline slice selection, landmark and reference line definitions, and measurement technique on T1-weighted sagittal images. Twenty MR images were reviewed by 2 pediatric neurosurgeons, 1 pediatric radiologist, and 1 undergraduate student. Measurements were performed using the technique specified on 2 separate occasions. Intrarater and interrater reliabilities were calculated using the intraclass correlation coefficient.RESULTSA combined interrater reliability of 0.879 was achieved for the pB-C2, and 0.916 for the clival-canal angle, another measure of interest in patients with complex Chiari malformations. Intrarater reliability for these measurements exceeded 0.858 for all 4 reviewers.CONCLUSIONSGrabb’s line—the pB-C2—can be measured with excellent reliability using a standardized measurement protocol. Individual clinicians and collaborative databases should consider using validated measurement techniques to guide clinical decision making in patients with craniocervical junction pathology.

Effect of different substrates on survival and growth of juveniles of the freshwater narrow-clawed crayfish Astacus leptodactylus Eschscholtz, 1823 (Decapoda, Astacidae)

Crustaceana ◽  
2017 ◽  
Vol 90 (11-12) ◽  
pp. 1289-1302 ◽  
Author(s):  
Yavuz Mazlum ◽  
Ozlem Guner Gurlek ◽  
Sinem Sirin
Keyword(s):  
Survival Rate ◽  
Treatment Group ◽  
Total Yield ◽  
Control Group ◽  
Astacus Leptodactylus ◽  
Growth Increase ◽  
Key Factor ◽  
Flow Through ◽  
Survival And Growth ◽  
Intermediate Value

Substrate is a key factor for successful crayfish culture, and it can be used to increase the survival rate. The effects of substrate on the survival and growth ofAstacus leptodactylusEschscholtz, 1823 were evaluated in flow-through compartments, divided into three sections and with two different substrates, over a period of 90 days. The three treatments used in the study were: artificial ropes, small stones, and a control group that received no substrate. The survival rate was highest in the small-stones treatment group (77.3%) and was lowest in the without-substrate treatment group (41.3%), while the artificial-ropes group showed an intermediate value (65.3%). Total yield was lower in the control group, 22.46% (25.0 g) as compared to the small-stones treatment group, with 42.3% (51.3 g) and the artificial-ropes treatment with 35.51% (55.8 g). In addition, cheliped injuries were found in higher proportion in the group without cover, and the artificial ropes yielded better results compared to the small-stones and no-substrate group in regard of the growth-increase rate.

Connecting Across Competencies: Leveraging Best Practices for Processing

2021 ◽  
Vol 55 (s3) ◽  
pp. 6-11
Author(s):  
Terra A. Kremer ◽  
Kaumudi Kulkarni ◽  
Christopher Ratanski ◽  
Lorraine Floyd ◽  
Christopher Anderson
Keyword(s):  
Best Practices ◽  
Medical Devices ◽  
Technical Information ◽  
Test Sample ◽  
Positive Control ◽  
Standard Test ◽  
Test Method ◽  
Cleaning Validation ◽  
Validation Parameters ◽  
Method Suitability

Abstract The AAMI working group ST/WG 93 is finalizing a standard (AAMI ST98) for the cleaning validation of reusable medical devices based on guidance from the technical information report AAMI TIR30:2011/(R)2016. A number of analytical best practices are being considered for this new standard. Test method suitability for processing cleaning validations historically has been established using one positive control and performing an extraction efficiency. The new cleaning validation standard is proposed to require a change from only one replicate test sample to three when performing method suitability. This change will affect manufacturers; therefore, the value of and consideration for performing these additional replicates requires explanation. This article discusses how variation of validation parameters can affect the accuracy and precision during method suitability testing. Multiple replicates are needed to understand the variability of method extraction and impact on cleaning validations of reusable medical devices.

Optical Analysis of Solar Concentrators Using Photogrammetry Process

2017 ◽  
pp. 175-201
Author(s):  
Safa Skouri ◽  
Salwa Bouadila
Keyword(s):  
Measurement Technique ◽  
Measurement Techniques ◽  
High Impact ◽  
Geometric Errors ◽  
Solar Concentrator ◽  
Optical Analysis ◽  
Optical Efficiency ◽  
Solar Concentrators ◽  
Displacement Error ◽  
Slope Error

As the optical efficiency of solar concentrators has a high impact on its thermal performance. However a qualification method determining the geometrical accuracy of a solar concentrator system is necessary. The purpose of this chapter is to gives an optical analysis of solar concentrator with an imaging process in order to improve the thermal efficiency of the solar concentrator. In this order measurement techniques used to determine geometric errors of the solar concentrating system have been described. Intercept factor, slope error and displacement error have been identified and analyzed. Examples of the intercept factor for concentrator reflector along with optical efficiency has been developed and determined related to the experimental results given by photogrammetry measurement technique.

scholarly journals A 3D comparison of humeral head retroversion by sex and measurement technique

2017 ◽  
Vol 10 (3) ◽  
pp. 192-200 ◽  
Author(s):  
Emily A. West ◽  
Nikolas K. Knowles ◽  
George S. Athwal ◽  
Louis M. Ferreira
Keyword(s):  
Measurement Technique ◽  
Humeral Head ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Distal Humerus ◽  
3D Models ◽  
Flexion Extension ◽  
Computed Tomography Scans ◽  
Osteotomy Plane ◽  
Version Measurement

Background Accurate humeral head reconstruction during shoulder arthroplasty is partially dependent on correctly estimating and replicating native version. The present study evaluated the effects of sex and measurement technique on three-dimensional (3D) humeral version measurements made using the transepicondylar, forearm and flexion–extension axes. Methods Fifty-two full-arm computed tomography scans were converted to 3D models and geometry extracted to define landmarks and coordinate systems. An anatomic humeral head osteotomy plane was used to measure version relative to the three measurement techniques and compare between sexes. Results The measurement technique used had a significant affect ( p < 0.001) on the resulting version measurement. The forearm axis technique consistently resulted in higher measured version compared to either the flexion–extension [mean (SD) males 9° (4°), females 13° (5°), p < 0.001] or the transepicondylar axes [mean (SD) males 8° (4°), females 11° (4°), p < 0.001]. Version in males was 7° greater than females when referencing either the flexion–extension [ p = 0.029; mean (SD) males 37.7° (11°), females 30.4° (13°)] or transepicondylar axes [ p = 0.045; mean (SD) males 39° (11°), females 32° (12°)]. Conclusions The choice of measurement technique can affect the humeral version angle. These results are important because measuring version using the epicondyles pre-operatively, and subsequently the forearm intra-operatively, will result in approximately 10° under-retroverted osteotomy. For example, 0° neutral version cut during reverse arthroplasty measured referencing the forearm results in 10° anteverted osteotomy when referencing the distal humerus.

X-Ray Imaging of the Filling of “T” Shaped Microchannel Using a MEDIPIX2 Pixel Detector

2004 ◽  
Author(s):  
A. Vabre ◽  
E. Manach ◽  
O. Gal ◽  
S. Legoupil
Keyword(s):  
Measurement Technique ◽  
Chemical Engineering ◽  
Measurement Techniques ◽  
Photon Counting ◽  
Pixel Detector ◽  
Lab On Chip ◽  
X Ray ◽  
Space Resolution ◽  
Research Perspectives ◽  
European Collaboration

Fluid flows in “T” or “Y” shaped structures of microchannels are studied in order to develop modeling approaches as well as adapted measurement techniques. The applications of these structures are numerous and concern in particular biology and chemical engineering for which the integration of microchannels in lab-on-chip and/or microreactor is an important challenge. Our works concern the development of a measurement technique for the study of the filling of a “T” shaped microchannel structure by a liquid. In the studied channels, the experimental constraints are strong. Indeed, the space steps involved within the phenomena are very much reduced and vary from 1 to 10 μm. Moreover, the dynamics of the flow implies a high acquisition frequency, ranging from 10 to 100 Hz. Our technological choice is based on the measurement of the attenuation of an X-ray beam in the matter. The main advantage of this non-intrusive technique is that it can be implemented even in media opaque to visible light. Also, that X-ray techniques can theoretically reach a better space resolution than optical ones. The measurement technique is quantitative and a 3D measurement is achievable by tomography. These methods are validated for problems located at centimetric space steps and high acquisition frequencies, [1], [2]. The objective of this work is to match the microfluidics field requirement (space steps and attenuation contrast), while preserving high time frequencies. Our experimental bench consists of a X-ray generator, that makes possible to obtain high enlargements of the observed object whit a reduced blur in the image. The image is obtained by a pixel detector called Medipix2. This detector is under development within a European collaboration which gathers 16 partners around the CERN, the CEA being a partner. The main assets of this detector are its high space resolution, its operational photon counting mode and its high acquisition frequency. The presented works constitute a very first implementation and validation of the proposed technique for the microfluidics field. Experimental results are obtained and presented. They allow a measurement of the filling conditions of the “T” shape structure of microchannels. The orientations and research perspectives to improve the obtained results by the technique could be evaluated accurately and important basis of our work are now established and quantified for the future.

Hand-Product Contact Point Detection on Surgical Instruments – A User Evaluation

2019 ◽  
Vol 27 (4) ◽  
pp. 14-21
Author(s):  
Álvaro M. Sampaio ◽  
Paulo Simões ◽  
Pedro Arezes ◽  
António J. Pontes
Keyword(s):  
Medical Devices ◽  
Contact Point ◽  
Evaluation Study ◽  
Surgical Instruments ◽  
User Evaluation ◽  
Hand Tools ◽  
Contact Areas ◽  
Ensure Patient Safety ◽  
Key Factor ◽  
Point Detection

The interaction of hand tools with the user is crucial and a key factor for his or her performance. In specific medical devices like surgical instruments, it is also important to ensure patient safety, namely, to avoid the risk of a surgical instrument’s being left inside a body. This article investigates the patterns of hand-to-product contact areas by identifying the potential locations to couple an external add-on tracing device on surgical instruments. A user evaluation study was conducted to determine the contact areas between the surgeons’ hands and different surgical instruments. The methodology, the results, and a discussion are described below.

scholarly journals A review of the measurement of sediment yield in different scales

2005 ◽  
Vol 58 (3) ◽  
pp. 257-265 ◽  
Author(s):  
José Carlos de Araújo ◽  
Donald W. Knight
Keyword(s):  
Spatial Resolution ◽  
Measurement Technique ◽  
Sediment Yield ◽  
Catchment Area ◽  
Review Paper ◽  
Graphical Representation ◽  
State Of The Art ◽  
Measurement Techniques ◽  
Annual Average ◽  
Global Data

The present review paper has the objective of presenting and briefly discussing the state-of-the-art papers on sediment yield (SY) measurement. About 80 publications are referred to, representing all continents, and more than 30 countries. It is observed that SY measurement technique is a much stronger function of temporal than of spatial resolution. Annual average SY data of 364 catchments are summarized. Global data presents no trend concerning catchment area and the same behavior is observed for the continents, except for Africa, which presents a consistent decrease of SY with increasing area. A graphical representation of the spatial and temporal applicability of the different SY measurement techniques is shown.

scholarly journals Nondestructive Testing of Ceramic Hip Joint Implants with Laser Spot Thermography

2017 ◽  
Vol 62 (4) ◽  
pp. 2133-2139
Author(s):  
J. Roemer ◽  
L. Pieczonka ◽  
M. Juszczyk ◽  
T. Uhl
Keyword(s):  
Damage Detection ◽  
Measurement Techniques ◽  
Infrared Camera ◽  
Field Measurements ◽  
Ceramic Materials ◽  
Test Sample ◽  
Theoretical Background ◽  
Laser Spot ◽  
Signal Acquisition ◽  
Full Field

AbstractThe paper presents an application of laser spot thermography for damage detection in ceramic samples with surface breaking cracks. The measurement technique is an active thermographic approach based on an external heat delivery to a test sample, by means of a laser pulse, and signal acquisition by an infrared camera. Damage detection is based on the analysis of surface temperature distribution near the exciting laser spot. The technique is nondestructive, non-contact and allows for full-field measurements. Surface breaking cracks are a very common type of damage in ceramic materials that are introduced in the manufacturing process or during the service period. This paper briefly discusses theoretical background of laser spot thermography, describes the experimental test rig and signal processing methods involved. Damage detection results obtained with laser spot thermography are compared with reference measurements obtained with vibrothermography. This is a different modality of active thermography, that has been previously proven effective for this type of damage. We demonstrate that both measurement techniques can be effectively used for damage detection and quality control applications of ceramic materials.

scholarly journals Experimental and theoretical analysis of (water) permeability variation of nonwoven textiles subjected to compression

2017 ◽  
Vol 18 (3) ◽  
pp. 307 ◽  
Author(s):  
Petrica Turtoi ◽  
Traian Cicone ◽  
Aurelian Fatu
Keyword(s):  
Theoretical Analysis ◽  
Thin Layer ◽  
Water Permeability ◽  
Darcy Law ◽  
Plane Flow ◽  
Flow Through ◽  
Forchheimer Model ◽  
Nonwoven Textiles ◽  
Original Device

This paper presents the experimental determination of permeability for unidirectional in-plane flow through a thin layer of nonwoven porous textile subjected to various rates of compression. The experiments were made on an original device that allows the variation of porous layer compression and pressure differential. The permeability was calculated assuming the validity of Darcy law and, in parallel, Darcy-Forchheimer model. The preliminary results obtained with water show that pressure gradient does not influence sensibly the resistance to flow of the material and Darcy’s law is applicable. For permeability-porosity correlation the experimental results were fitted using the well-known Kozeny-Carman equation. Also good correlation was found with other two models derived from Kozeny-Carman.

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