scholarly journals The mechanical characteristics and performance evaluation of a newly developed silicone airway stent (GINA stent)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hwa Sik Jung ◽  
Ganghee Chae ◽  
Jin Hyoung Kim ◽  
Chui Yong Park ◽  
Soyeoun Lim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Tissue Formation ◽  
Short Term ◽  
Granulation Tissue Formation ◽  
Airway Stent ◽  
Dumon Stent ◽  
And Performance ◽  
Expansion Force ◽  
Term Performance

AbstractCentral airway obstruction (CAO) can be attributed to several benign or malignant conditions. Although surgery is the preferred therapeutic option for the management of CAO, bronchoscopic treatment can be performed in scenarios where the surgical procedure is not possible. Recent years have witnessed several improvements in the field of bronchoscopic treatment, especially with regard to airway stents. Current research involves new attempts to overcome the existing shortcomings pertaining to the stents (migration, mucostasis, and granulation tissue formation). The authors have recently developed a new silicone airway stent (GINA stent) with an anti-migration design, dynamic structure that enables the reduction of stent cross-sectional area, and radio-opacity. The present study aimed to evaluate the mechanical characteristics and performance of the novel GINA stent using a porcine tracheal stenosis model. In the current study, all the tests involved the comparison of the GINA stent [outer diameter (OD, mm): 14; length (L, mm): 55] with the Dumon stent (OD: 14; L: 50). The mechanical tests were performed using a digital force gauge, in order to determine the anti-migration force, expansion force, and flexibility. The present study evaluated the short-term (3 weeks) performance of the two stents after implantation [GINA (n = 4) vs. Dumon (n = 3)] in the porcine tracheal stenosis model. The results pertaining to the comparison of the mechanical properties of the GINA and Dumon stents are stated as follows: anti-migration force (18.4 vs. 12.8 N, P = 0.008); expansion force (11.9 vs. 14.5 N, P = 0.008); and flexibility (3.1 vs. 4.5 N, P = 0.008). The results pertaining to the comparison of the short-term performance of the GINA and Dumon stents are stated as follows: mucus retention (0/4 vs. 0/3); granulation tissue formation (0/4 vs. 0/3); and migration (1/4 vs. 2/3). The GINA stent displayed better mechanical properties and comparable short-term performance, compared to the Dumon stent.

scholarly journals Newly developed silicone airway stent (GINA stent): Mechanical characteristics and performance evaluation in pigs

2020 ◽  
Author(s):  
Hwa Sik Jung ◽  
Ganghee Chae ◽  
Jin Hyoung Kim ◽  
Soohyun Bae ◽  
Chui Yong Park ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Granulation Tissue ◽  
Mechanical Characteristics ◽  
Tissue Formation ◽  
Short Term ◽  
Granulation Tissue Formation ◽  
Airway Stent ◽  
Dumon Stent ◽  
And Performance ◽  
Expansion Force

ABSTRACTOBJECTIVESCentral airway obstruction (CAO) is caused by various malignant and benign processes. Surgery is a preferred option for CAO, but if not possible, bronchoscopic treatment could be performed. Recently, bronchoscopic treatments have been improved. Particularly in airway stents, new attempts are being made to overcome the existing shortcomings of stents (migration, mucostasis, and granulation tissue formation). We recently developed a new silicone airway stent (GINA stent). The GINA stent has anti-migration design, dynamic structure enabling reduction of stent cross-sectional area, and radiopaqueness. We sought to evaluate mechanical characteristics and performance of our novel GINA stent in a pig tracheal stenosis model.METHODSAll tests were performed by comparing GINA stent [outer diameter (OD, mm) 14, length (L, mm) 55] with Dumon stent (OD14L50). Mechanical tests were done using digital force gage to determine the anti-migration force, expansion force, and flexibility. Short-term (3 weeks) performance was evaluated after stent implantations [GINA (n = 4) vs. Dumon (n = 3)] in a pig model of tracheal stenosis.RESULTSMechanical properties outcomes for GINA vs. Dumon: anti-migration force [18.4 vs. 12.8 Newton (N)]; expansion force (11.9 vs. 14.5 N); flexibility (3.1 vs. 4.5 N). Short-term (3 weeks) GINA vs. Dumon performances: mucus retention (0/4 vs. 0/3); granulation tissue formation (0/4 vs. 0/3); migration (1/4 vs. 2/3).CONCLUSIONSGINA stent demonstrated better mechanical properties than Dumon stent with a stent performance not inferior to Dumon stent.

Performance of Flexible and Rigid Pavements in Ohio

1996 ◽  
Vol 1536 (1) ◽  
pp. 94-102
Author(s):  
Hamid Mukhtar ◽  
Osama Abdulshafi
Keyword(s):  
Performance Prediction ◽  
Performance Data ◽  
Functional Classification ◽  
Short Term ◽  
Rigid Pavement ◽  
Rigid Pavements ◽  
And Performance ◽  
Variance Estimates ◽  
Term Performance ◽  
Prediction Parameters

Deviations in traffic and performance prediction parameters and overall standard deviations applicable to Ohio were determined. Pavement test sites were selected to represent the statewide distribution of pavement designs in Ohio, characterized by such factors as material type, functional classification, and different climatic and soil regions. Core samples were obtained and several laboratory tests were conducted to determine the as-constructed material properties and variability of the design input parameters. Comparison of predicted and observed performances based on approximately 4 years of data indicated that the AASHTO equation does not predict the performance of flexible pavements in Ohio. The predicted and the observed performances for rigid pavement sites were essentially the same, that is, no change in the observed and the predicted pavement serviceability index (PSI); however, these observations were based on short-term performance data. The overall variance estimates for flexible and rigid pavements were not obtained due to lack in the change of performance data for most sections.

Investigation of Mechanical Properties of Composite Made from Hemp and Polylactide

2016 ◽  
Vol 721 ◽  
pp. 63-67
Author(s):  
Rūta Stapulionienė ◽  
Saulius Vaitkus ◽  
Sigitas Vėjelis
Keyword(s):  
Mechanical Properties ◽  
Compressive Stress ◽  
Mechanical Characteristics ◽  
Mechanical Tests ◽  
Short Term ◽  
Hemp Fibers

This paper presents the research on the structure, short-term compression and tension of hemp fibers composite. The density of hemp fibers composite varied from ~40 to ~96 kg/m3. The mechanical characteristics of such hemp fibers composite mostly depend on the materials structure and density. By the mechanical tests it was determined that compressive stress of the hemp fibers composite depends on the direction of the load to the specimens face (perpendicular, across and parallel to the direction of formation).

Knowledge inflows effects on middle managers’ ambidexterity and performance

2015 ◽  
Vol 53 (10) ◽  
pp. 2303-2320 ◽  
Author(s):  
Juan Pablo Torres ◽  
Camilo Drago ◽  
Claudio Aqueveque
Keyword(s):  
Middle Managers ◽  
Methodological Approach ◽  
Strategic Decision ◽  
Top Down ◽  
Short Term ◽  
Content Type ◽  
Decision Performance ◽  
And Performance ◽  
Term Performance ◽  
New Strategies

Purpose – The purpose of this paper is to report on lab experiments conducted to determine what impact managerial top-down knowledge transfer has on a middle manager’s individual ambidexterity and decision performance. Design/methodology/approach – The authors designed an experimental approach using a business simulator to test the hypotheses with middle managers. The methodological approach provides the authors with a framework to enhance the middle manager’s understanding of how to attain superior short-term financial results by exploiting current resources, in addition to mastering new strategies to avoid a potential business bankruptcy. Findings – The results suggest that top-down managerial knowledge inflow benefits middle manager strategic decision making, as well as his/her short- and long-term performance. Nonetheless, the best short-term results were achieved by those middle managers that mastered both exploitation and exploration activities simultaneously. Originality/value – The contribution of this paper is to identify and test a control mechanism called top-down inflows that enhance middle manager’s ability to exploit current resources to increase financial performance, and exploring new strategies to avoid a business bankruptcy.

Verleimung von Laubholz für den tragenden Einsatz | Gluing of hardwood for supporting construction elements

2004 ◽  
Vol 155 (12) ◽  
pp. 533-539 ◽  
Author(s):  
Andrea Bernasconi
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Research Projects ◽  
Construction Engineering ◽  
The Past ◽  
Characteristic Values ◽  
And Performance

The better mechanical characteristics and sometimes also the higher durability of hardwood compared to softwood render it useful in construction engineering. What is important when hardwood is used is that the possibility is given of a faultless adhesion, as only then can products be made that fulfil modern requirements with regard to quality and performance. Although the successful practical use of glued hardwood has existed for decades, it is only in the past few years that systematic analyses have been carried out. In the present work we examine fundamental questions regarding the production and use of glued hardwood for supporting construction elements,discuss the types of wood suitable for processing in this way and describe some results from various research projects on the gluing of hardwood to produce construction elements. From this we can draw conclusions on the mechanical properties,performance and the achievable characteristic values of these products.

Use of a nitinol stent to treat dysphagia post-laryngopharyngectomy

2003 ◽  
Vol 117 (1) ◽  
pp. 78-79 ◽  
Author(s):  
Patrick Sheahan ◽  
Michael A. Walsh
Keyword(s):  
Conservative Treatment ◽  
Granulation Tissue ◽  
Tissue Formation ◽  
Term Result ◽  
Short Term ◽  
Jejunostomy Tube ◽  
Granulation Tissue Formation ◽  
Nitinol Stent ◽  
Long Term Result

Permanent dysphagia occurring after laryngectomy or laryngopharyngectomy is uncommon, and when it does occur, can usually be treated by periodic dilatation under general anaesthesia. Occasionally, however, conservative treatment is insufficient, and patients require long-term feeding via a gastrostomy or jejunostomy tube. We describe the case of a man with an anastamotic stricture post-pharyngectomy who underwent insertion of a nitinol stent across the stricture for treatment of dysphagia. The patient’s swallowing was significantly improved in the short-term, however, ultimately, florid granulation tissue formation led to obstruction of the stent and a disappointing long-term result. This, to our knowledge, is the first documentation of the use of a stent to treat dysphagia in a patient post-laryngectomy or pharyngolaryngectomy.

Metallic Nanoneedles Arrays for TEM Sample Preparation “Lift-Out”

2012 ◽  
Author(s):  
Romaneh Jalilian ◽  
David Mudd ◽  
Neil Torrez ◽  
Jose Rivera ◽  
Mehdi M. Yazdanpanah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Sample Preparation ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Beam System ◽  
Transmission Electron ◽  
Nanoneedle Array ◽  
Superior Mechanical Properties ◽  
And Performance

Abstract The sample preparation for transmission electron microscope can be done using a method known as "lift-out". This paper demonstrates a method of using a silver-gallium nanoneedle array for a quicker sharpening process of tungsten probes with better sample viewing, covering the fabrication steps and performance of needle-tipped probes for lift-out process. First, an array of high aspect ratio silver-gallium nanoneedles was fabricated and coated to improve their conductivity and strength. Then, the nanoneedles were welded to a regular tungsten probe in the focused ion beam system at the desired angle, and used as a sharp probe for lift-out. The paper demonstrates the superior mechanical properties of crystalline silver-gallium metallic nanoneedles. Finally, a weldless lift-out process is described whereby a nano-fork gripper was fabricated by attaching two nanoneedles to a tungsten probe.

Weldability - Behavior of Welded Reinforcement

2019 ◽  
Vol 70 (10) ◽  
pp. 3469-3472
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Mechanical Characteristics ◽  
Mechanical Performance ◽  
Current Work ◽  
Carbon Equivalent ◽  
Work Process ◽  
Ultimate Limit

Weldability involves two aspects: welding behavior of components and safety in operation. The two aspects will be reduced to the mechanical characteristics of the elements and to the chemical composition. In the case of steel reinforcing rebar’s, it is reduces to the percentage of Cech(carbon equivalent) and to the mechanical characteristics: the yielding limit, the ultimate limit, and the elongations which after that represent the ductility class in which the re-bars is framed. The paper will present some types of steel reinforcing rebar’s with its mechanical characteristics and the welding behavior of those elements. In the current work, process-related behavior of welded reinforcement, joint local and global mechanical properties, and their correlation with behavior of normal reinforcement and also the mechanical performance resulted in this type of joints. Keywords: welding behavior, ultimate limit, reinforcing rebar’s

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