Crack Detection by Wavelet-Based Acoustic Emission Test In Vitro Cemented Implant

2010 ◽  
Vol 638-642 ◽  
pp. 558-563
Author(s):  
Nuno Eduardo Dias Gueiral ◽  
Elisabete Maria da Silva Marques Nogueira ◽  
Antonio Manuel de Amaral Monteiro Ramos
Keyword(s):  
Acoustic Emission ◽  
Wavelet Transform ◽  
Femoral Component ◽  
Crack Detection ◽  
Microscopic Analysis ◽  
Optical Microscope ◽  
Cement Mantle ◽  
Monitoring Test ◽  
Acoustic Emission Test

One the mechanisms of failure in total hip arthroplasty in cemented prosthesis is cement fatigue. The main objective of this work is to use Acoustic Emission (AE) as a non-destructive and non-intrusive monitoring test in a cemented prosthesis. The femoral component was sinusoidally loading in a fatigue machine. Experimental data collected during acoustic emission test was treated and analysed by Wavelet Transform and allowed to locate a crack in cement mantle of femoral component. Other complementary diagnostic tests were used to confirm the existence of a fault (crack). One of them was penetrating liquids in different cut sections of femoral component. The other one was microscopic analysis that allowed observing the existence of a crack which location is pointed out by the results of AE answer. The AE sources locations are situated inside the crack observed in the optical microscope. The Wavelet Transform (WT) AE signals demonstrated the accuracy of damage location in bone cement and thus becoming useful in other orthopedics studies.

Shape Optimization of Femoral Components of an Artificial Hip Prosthesis Using the Three-Dimensional P-Version Finite Element Study and the In Vitro Measurement of Strain in the Bone Cement

2002 ◽  
Author(s):  
Masaru Higa ◽  
Ikuya Nishimura ◽  
Kazuhiro Matsuda ◽  
Hiromasa Tanino ◽  
Yoshinori Mitamura
Keyword(s):  
Finite Element ◽  
Shape Optimization ◽  
Bone Cement ◽  
Femoral Component ◽  
Three Dimensional ◽  
Femoral Stem ◽  
Cement Mantle ◽  
Optimum Shape ◽  
Shear Stresses

Though Total Hip Arthroplasty (THA) is being performed with greater frequency every year for patients with endstage arthritis of hip, mechanical fatigue of bone cement leading to damage accumulation is implicated in the loosening of cemented hip components. This fatigue failure of bone cement has been reported to be the result of high tensile and shear stresses at the bone cement. The aim of this study is to design the optimum shape of femoral component of a THA that minimizes the peak stress value of maximum principal stress at the bone cement and to validate the FEM results by comparing numerical stress with experimental ones. The p-version three-dimensional Finite Element Method (FEM) combined with an optimization procedure was used to perform the shape optimization. Moreover the strain in the cement mantle surrounding the cemented femoral component of a THA was measured in vitro using strain gauges embedded within the cement mantle adjacent to the developed femoral stem to validate the optimization results of FEM.

A comparison of 2 cementing techniques in hip resurfacing using human femoral heads

2021 ◽  
pp. 112070002199706
Author(s):  
Sarah J Shiels ◽  
Martin Williams ◽  
Gordon C Bannister ◽  
Richard P Baker
Keyword(s):  
Femoral Head ◽  
Femoral Component ◽  
Bubble Formation ◽  
Young Male ◽  
Cement Mantle ◽  
Hip Resurfacing ◽  
Air Bubble ◽  
Low Viscosity ◽  
Femoral Heads ◽  
Group 2

Introduction: Hip resurfacing remains a valid option in young male patients. The creation of the optimum cement mantle aids fixation of the femoral component. If the cement mantle is too thick the prosthesis can remain proud leading to early failure or if it penetrates too far into the femoral head, it may cause osteonecrosis. Method: 18 of 96 femoral heads collected from patients undergoing total hip arthroplasty were matched for their surface porosity. They were randomly allocated into 2 different cementing groups. Group 1 had the traditional bolus of cement technique, while group 2 had a modified cementing technique (swirl) where the inside of the femoral component was lined with an even layer of low viscosity cement. Results: The traditional bolus technique had significantly greater cement mantle thickness in 3 of 4 zones of penetration ( p = 0.002), greater and larger air bubble formation (6 of 9 in bolus technique vs. 1 in 9 in swirl technique, p = 0.05) and more incomplete cement mantles compared with the swirl technique. There was no relationship to femoral head porosity. Conclusion: The swirl technique should be used to cement the femoral component in hip resurfacing. Long-term clinical studies would conform if this translates into increased survivorship of the femoral component.

Stromal cell and human prostatic epithelial cell in-vitro co-coltures: Growth and morphology

1996 ◽  
Vol 63 (1_suppl) ◽  
pp. 65-68
Author(s):  
S. De Angeli ◽  
A. Fandella ◽  
C. Gatto ◽  
S. Buoro ◽  
C. Favretti ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Stromal Cells ◽  
Marked Reduction ◽  
Stromal Cell ◽  
Optical Microscope ◽  
Neutral Red ◽  
Cellular Growth ◽  
Murine Fibroblasts ◽  
Prostatic Epithelial Cell

A study was carried out on the effect of stroma-epithelium interaction on cellular growth and morphology in co-coltures of U285 prostatic epithelial cells with human prostatic and esophageal stromal cells and with murine fibroblasts of the 3T3-J2 line. The proliferation rate was determined by growth tests of neutral red and kenacid blue. Morphological observations were made under optical microscope on the same cultures used for the growth tests. Results highlighted a marked reduction in cellular growth in the co-cultures compared to control cultures, as well as the tendency of the stromal and epithelial cells to re-organise themselves in pseudo-acinous structures.

On the Reproducibility of Transducer Coupling for Acoustic Emission Testing

2006 ◽  
Vol 13-14 ◽  
pp. 117-124 ◽  
Author(s):  
James J. Hensman ◽  
C.V. Cristodaro ◽  
Gareth Pierce ◽  
Keith Worden
Keyword(s):  
Acoustic Emission ◽  
Test Results ◽  
Coupling Condition ◽  
Waveform Data ◽  
Three Point Bending ◽  
Emission Testing ◽  
Acoustic Emission Testing ◽  
Acoustic Emission Test ◽  
Point Bend ◽  
Ultrasonic Propagation

An acoustic emission test was simulated using a three point bend specimen and an artificial AE source. Waveform data was recorded as the sample was cyclically loaded in three point bending, and the cross correlation coefficient of the waveforms was used to measure the repeatability of the test. Results were twofold: the stress state of a specimen affects the ultrasonic propagation therein; and the coupling condition of a transducer may not remain constant during a test.

scholarly journals Chemical Derivatization and Characterization of Novel Antitrypanosomals for African Trypanosomiasis

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4488
Author(s):  
Aboagye Kwarteng Dofuor ◽  
Temitayo Samson Ademolue ◽  
Cynthia Mmalebna Amisigo ◽  
Kwaku Kyeremeh ◽  
Theresa Manful Gwira
Keyword(s):  
Structural Modification ◽  
Spectroscopic Analysis ◽  
Microscopic Analysis ◽  
The Novel ◽  
Chemical Derivatization ◽  
African Trypanosomiasis ◽  
Chemical Structures ◽  
Normal Ratio

The search for novel antitrypanosomals and the investigation into their mode of action remain crucial due to the toxicity and resistance of commercially available antitrypanosomal drugs. In this study, two novel antitrypanosomals, tortodofuordioxamide (compound 2) and tortodofuorpyramide (compound 3), were chemically derived from the natural N-alkylamide tortozanthoxylamide (compound 1) through structural modification. The chemical structures of these compounds were confirmed through spectrometric and spectroscopic analysis, and their in vitro efficacy and possible mechanisms of action were, subsequently, investigated in Trypanosoma brucei (T. brucei), one of the causative species of African trypanosomiasis (AT). The novel compounds 2 and 3 displayed significant antitrypanosomal potencies in terms of half-maximal effective concentrations (EC50) and selectivity indices (SI) (compound 1, EC50 = 7.3 μM, SI = 29.5; compound 2, EC50 = 3.2 μM, SI = 91.3; compound 3, EC50 = 4.5 μM, SI = 69.9). Microscopic analysis indicated that at the EC50 values, the compounds resulted in the coiling and clumping of parasite subpopulations without significantly affecting the normal ratio of nuclei to kinetoplasts. In contrast to the animal antitrypanosomal drug diminazene, compounds 1, 2 and 3 exhibited antioxidant absorbance properties comparable to the standard antioxidant Trolox (Trolox, 0.11 A; diminazene, 0.50 A; compound 1, 0.10 A; compound 2, 0.09 A; compound 3, 0.11 A). The analysis of growth kinetics suggested that the compounds exhibited a relatively gradual but consistent growth inhibition of T. brucei at different concentrations. The results suggest that further pharmacological optimization of compounds 2 and 3 may facilitate their development into novel AT chemotherapy.

scholarly journals Structural Characterization andIn VitroAntioxidant Activity of Kojic Dipalmitate Loaded W/O/W Multiple Emulsions Intended for Skin Disorders

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Maíra Lima Gonçalez ◽  
Diana Gleide Marcussi ◽  
Giovana Maria Fioramonti Calixto ◽  
Marcos Antonio Corrêa ◽  
Marlus Chorilli
Keyword(s):  
Antioxidant Activity ◽  
Safety Profile ◽  
Flow Behavior ◽  
Microscopic Analysis ◽  
Skin Disorders ◽  
Activity Assay ◽  
Multiple Emulsions ◽  
Lipophilic Antioxidant ◽  
Newtonian Behavior

Multiple emulsions (MEs) are intensively being studied for drug delivery due to their ability to load and increase the bioavailability of active lipophilic antioxidant, such as kojic dipalmitate (KDP). The aim of this study was to structurally characterize developed MEs by determining the average droplet size (Dnm) and zeta potential (ZP), performing macroscopic and microscopic analysis and analyzing their rheological behavior andin vitrobioadhesion. Furthermore, thein vitrosafety profile and antioxidant activity of KDP-loaded MEs were evaluated. The developed MEs showed a Dnm of approximately 1 micrometer and a ZP of −13 mV, and no change was observed in Dnm or ZP of the system with the addition of KDP. KDP-unloaded MEs exhibited ‘‘shear thinning’’ flow behavior whereas KDP-loaded MEs exhibited Newtonian behavior, which are both characteristic of antithixotropic materials. MEs have bioadhesion properties that were not influenced by the incorporation of KDP. The results showed that the incorporation of KDP into MEs improved the safety profile of the drug. Thein vitroantioxidant activity assay suggested that MEs presented a higher capacity for maintaining the antioxidant activity of KDP. ME-based systems may be a promising platform for the topical application of KDP in the treatment of skin disorders.

In Vitro Anti-Biofilm Activity of Hydrogen-Peroxide Generating Electrochemical Bandage Against Yeast Biofilms

2021 ◽  
Author(s):  
Yash S. Raval ◽  
Abdelrhman Mohamed ◽  
Jayawant N. Mandrekar ◽  
Cody Fisher ◽  
Kerryl E. Greenwood-Quaintance ◽  
...  
Keyword(s):  
Membrane Damage ◽  
Microscopic Analysis ◽  
Viable Cell ◽  
Wound Infections ◽  
Unique Challenge ◽  
Cell Membrane Damage ◽  
Cell Counts ◽  
Extensive Cell ◽  
Fluorescence Microscopic Analysis

Wound infections are caused by bacteria and/or fungi. The presence of fungal biofilms in wound beds presents a unique challenge, as fungal biofilms may be difficult to eradicate. The goal of this work was to assess the in vitro anti-biofilm activity of a H 2 O 2 -producing electrochemical bandage (e-bandage) against 15 yeast isolates representing commonly-encountered species. Time-dependent decreases in viable biofilm CFU counts of all isolates tested were observed, resulting in no visible colonies with 48 hours of exposure by plate culture. Fluorescence microscopic analysis showed extensive cell membrane damage of biofilm cells after e-bandage treatment. Reductions in intracellular ATP levels of yeast biofilm cells were recorded post e-bandage treatment. Our results suggest that exposure to H 2 O 2 -producing e-bandages reduce in vitro viable cell counts of yeast biofilms, making this a potential new topical treatment approach for fungal wound infections.

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