Gore-Tex® ePTFE in Nasal Surgery and Review of Long-Term Results

1994 ◽  
Vol 11 (3) ◽  
pp. 179-182 ◽  
Author(s):  
Mark Berman
Keyword(s):  
Silicone Rubber ◽  
Structural Integrity ◽  
Subcutaneous Tissue ◽  
Long Term Results ◽  
Vacuum Impregnation ◽  
Nasal Surgery ◽  
Implant Material ◽  
Fda Approval ◽  
Antibiotic Solution ◽  
The Stability

More than 10 years have passed since the author first used Gore-Tex® expanded polytetrafluoroethylene (ePTFE) as a facial implant material. To date, the material has been tolerated very successfully without any signs of degradation or alteration. Previous research studies have confirmed the stability of the material. It has become increasingly popular and has recently received FDA approval as Subcutaneous Tissue Augmentation Material (SAM®) for use as a soft tissue filler of the face. More importantly, this author has documented two specific areas for consideration. First, the material does not need to be used by itself as an independent implant material. It can be bonded to other materials, such as silicone rubber, and thus be used for its unique surface properties while enjoying the structural integrity of the silicone rubber. (This use has not received FDA approval.) Secondly, as an added precaution, it is wise to prepare the material before implantation by vacuum impregnation with an antibiotic solution. Before use of this type of preparation was started in June 1989, the author experienced 9 infections out of 67 facial implants with Gore-Tex (13%). Since vacuum impregnation was initiated, there has been 1 infection out of 165 implantations (0.61%). There have been no infections or extrusions with nasal surgery since antibiotic impregnation was started.

Destabilizing the Structural Integrity of SARS-CoV2 Receptor Proteins by Curcumin Along with Hydroxychloroquine: An Insilco Approach for a Combination Therapy

2020 ◽  
Author(s):  
Akhileshwar Srivastava ◽  
Divya Singh
Keyword(s):  
Binding Energy ◽  
Combination Therapy ◽  
Receptor Binding ◽  
Structural Integrity ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Receptor Proteins ◽  
Main Protease ◽  
The Stability ◽  
Therapeutic Activities

Presently, an emerging disease (COVID-19) has been spreading across the world due to coronavirus (SARS-CoV2). For treatment of SARS-CoV2 infection, currently hydroxychloroquine has been suggested by researchers, but it has not been found enough effective against this virus. The present study based on in silico approaches was designed to enhance the therapeutic activities of hydroxychloroquine by using curcumin as an adjunct drug against SARS-CoV2 receptor proteins: main-protease and S1 receptor binding domain (RBD). The webserver (ANCHOR) showed the higher protein stability for both receptors with disordered score (<0.5). The molecular docking analysis revealed that the binding energy (-24.58 kcal/mol) of hydroxychloroquine was higher than curcumin (-20.47 kcal/mol) for receptor main-protease, whereas binding energy of curcumin (<a>-38.84</a> kcal/mol) had greater than hydroxychloroquine<a> (-35.87</a> kcal/mol) in case of S1 receptor binding domain. Therefore, this study suggested that the curcumin could be used as combination therapy along with hydroxychloroquine for disrupting the stability of SARS-CoV2 receptor proteins

scholarly journals Investigation of Hydrothermally Stressed Silicone Rubber/Silica Micro and Nanocomposite for the Coating High Voltage Insulation Applications

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3567
Author(s):  
Faiza Faiza ◽  
Abraiz Khattak ◽  
Safi Ullah Butt ◽  
Kashif Imran ◽  
Abasin Ulasyar ◽  
...  
Keyword(s):  
Silicone Rubber ◽  
Structural Changes ◽  
Polymer Chains ◽  
Hydrothermal Conditions ◽  
Silica Filler ◽  
Before And After ◽  
Aging Conditions ◽  
The Stability ◽  
Micro Silica ◽  
Applied Stresses

Silicone rubber is a promising insulating material that has been performing well for different insulating and dielectric applications. However, in outdoor applications, environmental stresses cause structural and surface degradations that diminish its insulating properties. This effect of degradation can be reduced with the addition of a suitable filler to the polymer chains. For the investigation of structural changes and hydrophobicity four different systems were fabricated, including neat silicone rubber, a micro composite (with 15% micro-silica filler), and nanocomposites (with 2.5% and 5% nanosilica filler) by subjecting them to various hydrothermal conditions. In general, remarkable results were obtained by the addition of fillers. However, nanocomposites showed the best resistance against the applied stresses. In comparison to neat silicone rubber, the stability of the structure and hydrophobic behavior was better for micro-silica, which was further enhanced in the case of nanocomposites. The inclusion of 5% nanosilica showed the best results before and after applying aging conditions.

On the Design of Contact Member Surface Shape of Bolted Joints to Minimize Clamping Load Loss

2018 ◽  
Author(s):  
Linbo Zhu ◽  
Yifei Hou ◽  
Abdel-Hakim Bouzid ◽  
Jun Hong
Keyword(s):  
Contact Surface ◽  
High Performance ◽  
Thermal Loading ◽  
Structural Integrity ◽  
Bolted Joints ◽  
Surface Shape ◽  
Geometrical Shape ◽  
Joint Surfaces ◽  
Joint Contact ◽  
The Stability

Metal to metal contact between joint surfaces is widely used in bolted joints to obtain a rigid and a high performance connection. However, a significant amount of clamping load is lost when the joint is subjected to mechanical and thermal loading including creep and fatigue. In practice, to prevent bolt loosening, additional parts such as spring washers, double nut, spring lock washers, Nyloc nut and so on are used. Those methods are costly and influence the stability of the joint and affect its structural integrity. It is well established that a small compression displacement in clamping parts leads to a big clamping load loss in stiff joints. This paper discusses the relationship between connection stiffness and clamping load and presents a method that improves clamping load retention during operation by a careful design of the member contact surface shape. A single bolted joint with two clamping parts is modeled using finite element method (FEM). A method is proposed to obtain a specific stiffness by an optimized geometrical shape of the joint contact surfaces. The result shows that the contact surface shape based on a gradually varying gap can improve the retention of the initial clamping load. Furthermore, a formula of the connection stiffness based on the curve fitting technique is proposed to predict residual clamping load under different external load and loosening.

scholarly journals Stability Tests of Agricultural and Operating Machines by Means of an Installation Composed by a Rotating Platform (the “Turntable”) with Four Weighting Quadrants

2020 ◽  
Vol 10 (11) ◽  
pp. 3786
Author(s):  
Marco Bietresato ◽  
Fabrizio Mazzetto
Keyword(s):  
Degrees Of Freedom ◽  
Structural Integrity ◽  
Support Surface ◽  
Rotating Platform ◽  
Technical Standards ◽  
Stability Tests ◽  
Support Plane ◽  
Stability Performance ◽  
Inclination Angles ◽  
The Stability

The stability of agricultural machines, earth-moving machines, snow-compaction machines and, in general, of all vehicles that may operate on sloping terrains is a very important technical feature and should not be underestimated. In fact, it is correlated, above all, to the safety of the operators, but also to the preservation of the structural integrity of these vehicles, to the prosecution of the activities and to the preservation of the economic investment. Although these facts are well-known, the international legislation and technical standards do not yet have a sufficient level of detail to give an all-inclusive quantification of the stability of the vehicle under examination in all its working conditions, e.g., at different inclination angles of the support surface, at different climbing angles of the vehicle on the slope, with different tires and inflating pressures, and on different terrains. Actual standards limit the stability tests to the experimental measurement of the lateral rollover angle only. Furthermore, the realization of unconventional test equipment able to widen the usually-tested scenarios could not be simple, due to the necessary size that such equipment should have (to perform tests not in scale) and to the related difficulties of handling full-scale vehicles. This work illustrates the applications of a new rig for testing the stability of vehicles, able to address all the above-illustrated issues and of possible future adoption to certify the stability performance of machines and perform homologations. This installation, named “rotating platform” or “turntable”, has the peculiarity of being able to move the machine positioned on it according to two rotational degrees of freedom: (1) overall inclination of the support plane, (2) rotation of the support plane around an axis perpendicular to the plane. The same installation is also designed to record the weight supported by each wheel of the machine placed on it (by means of four sensorized quadrants), both when the platform is motionless and while the above-described movements of tilt and rotation are being carried out, thus locating precisely the spatial position of the vehicle center of gravity. The presented physical-mathematical models highlight the great potential of this facility, anticipate the outcomes of the recordings that the experimenters will have at disposal when the test rig will be effectively active, and help the future understanding of trends of data, thus maximizing the available information content.

AE Damage Assessment in the Bell Tower of the Turin Cathedral

2019 ◽  
Vol 817 ◽  
pp. 579-585
Author(s):  
Amedeo Manuello ◽  
Davide Masera ◽  
Alberto Carpinteri
Keyword(s):  
Damage Assessment ◽  
Structural Integrity ◽  
Cumulative Number ◽  
Height Ratio ◽  
Value Analysis ◽  
Integrity Assessment ◽  
Bell Tower ◽  
The Stability ◽  
Good Agreement

Historical churches, masonry towers and bell towers are structures subjected to high risk, due to their age, elevation and low base area on height ratio. In this work, an innovative monitoring technique for structural integrity assessment of historical buildings is reported. At the same time, the emblematic case study of the Turin Cathedral Bell tower is presented. The damage evolution in the tall masonry structure is described by the evaluation of the cumulative number of AE and by different parameters able to predict the time dependence of damage. In particular, since environmental disturbances have been minimized, and instrumental noises have been filtered out. The b-value analysis shows a downward trend to values compatible with the growth of localized macro-cracks at the base of the tower. These results seem to be in good agreement with the numerical analysis. Extension to longer monitoring periods and, later, investigation of different segments are strongly recommended to assess the stability of the monument.

Étude de la pénétrabilité du coulis de ciment microfin sous pression dans les structures de maçonnerie dégradées à caractère historique : effet d'un agent colloïdal

2000 ◽  
Vol 27 (4) ◽  
pp. 642-654 ◽  
Author(s):  
Danielle Palardy ◽  
Stéphanie Perret ◽  
Gérard Ballivy ◽  
Robert Laporte
Keyword(s):  
Structural Integrity ◽  
Cement Grout ◽  
Public Works ◽  
Second Phase ◽  
Masonry Structures ◽  
Flow Rates ◽  
The Past ◽  
Microfine Cement ◽  
The Stability ◽  
Rideau Canal

Several masonry structures, built over the past centuries, have to be restored to ensure their structural integrity and their conservation. Important research and development projects have been initiated by Public Works and Government Services Canada to rehabilitate some of these structures, such as the Rideau canal locks, by using a cement-based grouting technique. By following grouting pressures and flow rates, the stability of the structure is protected and the efficiency to fill openings is assured by using microfine cement-based grouts with admixtures. However, cement grout penetration cannot be observed with precision during the injection. The project described in this paper presents the grouting treatment of a Rideau canal lock sill wall that had to be demolished and reconstructed. The penetration of two different grout mixes was observed by removing the front row of blocks, piece by piece. A second phase of this study was conducted in the laboratory to compare the penetration of different grouts in a reconstructed granular material which simulated the lock's interior walls.Key words: restoration, masonry, grouting, groutability, cement grout, colloidal agent.

Effect of RuO2 on Piezoresistive Properties of CB/MVQ Composite Materials

2014 ◽  
Vol 609-610 ◽  
pp. 124-129
Author(s):  
Ju Ying Wu ◽  
Jing Hui Fan ◽  
Yu Hong Huang ◽  
Jing Guo ◽  
Kai Zhang
Keyword(s):  
Composite Materials ◽  
Carbon Black ◽  
Silicone Rubber ◽  
Oxidation Reaction ◽  
Resistance Testing ◽  
Test Results ◽  
Sem And Tem ◽  
Pressure Resistance ◽  
The Stability

In this paper, RuO2-CB/MVQ composites were prepared through following steps. First, the nanoruthenium particles had been prepared by solvent thermo-deoxidization ways. Secondly, the nanoRuO2 particles had been formed by oxidation reaction of nanoruthenium particles in air. Thirdly, the carbon black/silicone rubber mixed rubber was prepared by solvent mixing. Fourthly, the nanoruthenium particles were mixed into carbon black/silicone rubber mixed rubber by rubbing dispersion. Finally, vulcanization molding was carried out at certain preasure and temperature. The piezoresistive properties of CB/MWQ composite materials were tested with pressure-resistance testing systems designed ourselves. The test results showed that suitable amounts of RuO2 could enhance the stability and creep of piezoresistive properties of CB/MWQ composite materials. The microstructure of CB/MWQ composite materials were analyzed with SEM and TEM. The characterization results showed that nanoRuO2 particles dispersed in composite materials in nanolevel. These nanostructure could improve conductive net of carbon black, and reinforce crosslink net of silicone rubber. These factors had advantage to the stability of piezoresistive properties of CB/MWQ composite materials.

scholarly journals Assessment of Structural Units Deletions in the Archaeal Oligosaccharyltransferase AglB

2020 ◽  
Author(s):  
Conrado Pedebos ◽  
Hugo Verli
Keyword(s):  
Structural Integrity ◽  
Transmembrane Domain ◽  
Functional Characterization ◽  
Wild Type Enzyme ◽  
Structural Units ◽  
Terminal Domain ◽  
Glycan Chain ◽  
The Stability ◽  
Dynamics Simulations ◽  
Binding Interfaces

AbstractOligosaccharyltransferases (OSTs) are enzymes that catalyze the transfer of a glycan chain to an acceptor protein. Their structure is composed by a transmembrane domain and a periplasmic / C-terminal domain, which can be divided into structural units. The Archaeoglobus fulgidus OST, AfAglB, has unique structural units with unknown functions. Here, we evaluate the stability role proposed for AfAglB units by employing molecular modelling and molecular dynamics simulations, to examine the effect of single and double deletions in the enzyme structure. Our results show a strong effect on the dynamics of the C-terminal domain for the mutated systems with increased fluctuations near the deleted areas. Conformational profile and stability are deeply affected, mainly in the double unit deletion, modifying the enzyme behavior and binding interfaces. Coordination at the catalytic site was not disrupted, indicating that the mutated enzymes could retain activity at some level. Hotspots of variation were identified and rationalized with previous data. Our data shows that structural units may provide stabilization interactions, contributing for integrity of the wild-type enzyme at high temperatures. By correlating our findings to structural units mutagenesis experimental data available, it was observed that structural units deletion can interfere with OSTs stability and dynamics but it is not directly related to catalysis. Instead, they may influence the OST structural integrity, and, potentially, thermostability. This work offers a basis for future experiments involving OSTs structural and functional characterization, as well as for protein engineering.

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