Monitoring the Stability of Artificial Prosthesis Performance for Hip Replacement

2019 ◽  
Vol 9 (10) ◽  
pp. 1395-1397
Author(s):  
Xingen Zhang ◽  
Xianjie Sun ◽  
Gang Shi
Keyword(s):  
Resonance Frequency ◽  
Hip Replacement ◽  
Joint Pain ◽  
Sensitive Technique ◽  
Non Invasive ◽  
Translational Studies ◽  
Analysis Of Stability ◽  
The Stability ◽  
Artificial Prosthesis

The hip replacement is beneficial to relieve joint pain and misfunction. We previously designed the model to monitor the stability of the artificial prosthesis during the surgery based on the resonance frequency (RF), which is a non-invasive and sensitive technique. In this study, we further applied the techniques to monitor its use in hip replacement and compared the effect in individuals. Our data have showed that resonance frequency is very promising for the analysis of stability of artificial prosthesis in hip replacement, and the performance of the technique is also promising for the translational studies in the clinic.

scholarly journals Effects of photofunctionalization on early osseointegration of titanium dental implants in the maxillary posterior region: a randomized double-blinded clinical trial

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Bada Choi ◽  
Ye Chan Lee ◽  
Kyung Chul Oh ◽  
Jae Hoon Lee
Keyword(s):  
Clinical Trial ◽  
Resonance Frequency ◽  
Bone Quality ◽  
Frequency Analysis ◽  
Treated Group ◽  
Posterior Region ◽  
Resonance Frequency Analysis ◽  
Group Iii ◽  
The Stability ◽  
Double Blinded

Abstract Background This study aimed to investigate the effects of ultraviolet (UV) photofunctionalization on the stability of implants during the early phase in the posterior region of the maxilla. The study was a randomized double-blinded clinical trial. Half of the participants received conventional commercial implants while the other half received UV-irradiated implants. The surgical sites were classified into three bone quality groups (II, III, IV) based on the grayscale value measured on cone-beam computed tomography. The values obtained from resonance frequency analysis were recorded immediately after implant placement and at 4 weeks and at 4 months postoperatively. The marginal bone level of the implants was evaluated using periapical radiographs at 4 weeks, 4 months, and 1 year postoperatively. Results Fifty-seven implants placed in 34 participants were analyzed in this study. In group III, significant differences were observed in terms of the differences of resonance frequency analysis values at 4 weeks (p = 0.004) and 4 months (p = 0.017) postoperatively. In group II, the UV-treated group showed significantly lesser bone loss at 4 weeks post-operatively (p = 0.037). Conclusions Within the limitation of the present study, we concluded that UV surface treatment on implants may increase the initial stability in the region of the maxilla with poor bone quality.

scholarly journals Mechanical and Electrical Performance of Flexible Polymer Film Designed for a Textile Electrically-Conductive Path

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2169
Author(s):  
Agnieszka Tabaczyńska ◽  
Anna Dąbrowska ◽  
Marcin Masłowski ◽  
Anna Strąkowska
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Surface Resistance ◽  
Conductive Filler ◽  
Extrusion Process ◽  
Electrical Performance ◽  
Electrically Conductive ◽  
Non Invasive ◽  
Flexible Polymer ◽  
The Stability

Electro-conductive paths that are mechanically resistant and stable during simulated aging cycles are promising, in relation to the non-invasive application in e-textiles in our everyday surroundings. In the paper, an analysis of the influence of electro-conductive filler, as well as ionic liquid on surface resistance is provided. Authors proved that depending on the tested variant, obtained surface resistance may vary from 50 kΩ (when 50 phr of Ag and [bmim][PF6] ionic liquid applied) to 26 GΩ (when 25 phr of Ag and [bmim][PF6] ionic liquid applied). The samples were also evaluated after simulated aging cycles and the stability of electric properties was confirmed. Moreover, it was proved that the addition of ionic liquids reduced the resistance of vulcanizates, while no significant influence of the extrusion process on conductivity was observed.

scholarly journals Stability and Instability in the Lysogenic State of Phage Lambda

2010 ◽  
Vol 192 (22) ◽  
pp. 6064-6076 ◽  
Author(s):  
John W. Little ◽  
Christine B. Michalowski
Keyword(s):  
Intrinsic Rate ◽  
Growth Conditions ◽  
Emergent Properties ◽  
Regulatory Circuits ◽  
Stability And Instability ◽  
Natural Range ◽  
Analysis Of Stability ◽  
Stable Association ◽  
The Stability ◽  
Gene Regulatory Circuits

ABSTRACT Complex gene regulatory circuits exhibit emergent properties that are difficult to predict from the behavior of the components. One such property is the stability of regulatory states. Here we analyze the stability of the lysogenic state of phage λ. In this state, the virus maintains a stable association with the host, and the lytic functions of the virus are repressed by the viral CI repressor. This state readily switches to the lytic pathway when the host SOS system is induced. A low level of SOS-dependent switching occurs without an overt stimulus. We found that the intrinsic rate of switching to the lytic pathway, measured in a host lacking the SOS response, was almost undetectably low, probably less than 10−8/generation. We surmise that this low rate has not been selected directly during evolution but results from optimizing the rate of switching in a wild-type host over the natural range of SOS-inducing conditions. We also analyzed a mutant, λprm240, in which the promoter controlling CI expression was weakened, rendering lysogens unstable. Strikingly, the intrinsic stability of λprm240 lysogens depended markedly on the growth conditions; lysogens grown in minimal medium were nearly stable but switched at high rates when grown in rich medium. These effects on stability likely reflect corresponding effects on the strength of the prm240 promoter, measured in an uncoupled assay system. Several derivatives of λprm240 with altered stabilities were characterized. This mutant and its derivatives afford a model system for further analysis of stability.

scholarly journals A susceptibility locus on chromosome 13 profoundly impacts the stability of genomic imprinting in mouse pluripotent stem cells

2020 ◽  
Author(s):  
Emily Swanzey ◽  
Thomas F. McNamara ◽  
Effie Apostolou ◽  
Mamta Tahiliani ◽  
Matthias Stadtfeld
Keyword(s):  
Culture Conditions ◽  
Mouse Strains ◽  
Genetic Determinant ◽  
Pluripotent Cells ◽  
Developmental Potential ◽  
Chromosome 13 ◽  
Non Invasive ◽  
Epigenetic Instability ◽  
Trait Locus ◽  
The Stability

SummaryCultured pluripotent cells accumulate detrimental epigenetic alterations, including DNA methylation changes at imprinted genes known as loss-of-imprinting (LOI). Despite the substantial biomedical relevance of this phenomenon, the molecular cause of this epigenetic instability in pluripotent cells remains unknown. While the occurrence of LOI is generally considered a stochastic phenomenon, here we document a strong genetic determinant that segregates mouse pluripotent cells into epigenetically stable and unstable cell lines. Unstable lines exhibit hypermethylation at Dlk1-Dio3 and select other imprinted loci, which is associated with impaired developmental potential. Stimulation of demethylases by ascorbic acid prevents LOI and can preserve developmental potential. Susceptibility to LOI greatly differs between commonly used mouse strains, which we utilize to map a causal region on chromosome 13 with Quantitative Trait Locus (QTL) analysis. Our observations identify a strong genetic determinant of locus-specific epigenetic abnormalities in pluripotent cells and provide a non-invasive way to suppress them. This highlights the importance of considering genetics in conjunction with culture conditions for assuring the quality of pluripotent cells for biomedical applications.

Stability of Earth Masses and Slopes

2015 ◽  
pp. 528-588
Keyword(s):  
Cross Sections ◽  
Limit Equilibrium ◽  
Circle Method ◽  
Earth Dam ◽  
Stability Of Slopes ◽  
Solution Of Equations ◽  
Analysis Of Stability ◽  
The Stability ◽  
Cut Slopes ◽  
Type Of Failure

The design of open-cut slopes and embankments, foundations, levees, and earth-dam cross-sections is based primarily on stability considerations. There are many causes and types of earth instability. There are also many ways of analyzing the stability of slopes. The chapter considers the limit equilibrium approach, which aims essentially to determine a factor of safety, F, that would ensure a slope does not fail. The chapter considers the analysis of stability of infinite slopes based on translational type of failure and the analysis of finite slopes using the Swedish Method, Method of Slices, Bishop Simplified Method, Friction Circle Method, and the Translational Method. The solution of equations developed for the analysis of stability of slopes can be tedious and time consuming. A way of reducing the amount of calculation required in slope stability studies is by use of charts based on geometric similarity. The chapter discusses how Taylor (1948) and Janbu (1964) charts are used in stability analysis of slopes. Finally, the chapter discusses ways to reduce the risk of instability in slopes.

scholarly journals Biomimetic remineralization of acid etched enamel using agarose hydrogel model

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1476 ◽  
Author(s):  
Sara El Moshy ◽  
Marwa M.S. Abbass ◽  
Amal M. El-Motayam
Keyword(s):  
Phosphate Solution ◽  
Tooth Structure ◽  
Non Invasive ◽  
Minimally Invasive Dentistry ◽  
Demineralized Enamel ◽  
Agarose Hydrogel ◽  
Roughness Analysis ◽  
Acid Gel ◽  
The Stability ◽  
Mandibular Third Molars

Background: Minimally invasive dentistry aims to prevent progression of caries and treats non-cavitated lesions through non-invasive approaches to preserve the integrity of tooth structure. The aim of this research was to investigate the possible biomimetic effect of agarose hydrogel in remineralizing a human demineralized enamel model. Methods: Mandibular third molars were distributed into three groups (G1, G2 and G3) according to the follow up time (2, 4 and 6 days respectively). Caries like lesion was prepared by applying 37% phosphoric acid gel for 1 minute and then remineralization was performed through applying agarose hydrogel on the demineralized surfaces. The specimens were placed in phosphate solution at 37˚C for 2, 4 & 6 days. Scanning electron microscope (SEM), surface microhardness (SMH) and surface roughness analysis (SR) were performed to assess the regenerated tissue. Results: SEM revealed mineral depositions on the demineralized enamel surface that increased in density by time resulting in a relatively smooth surface in G3. SR and SMH analysis revealed significant differences between the remineralized enamel surfaces of different groups (p< 0.00001) with the highest SR in G1 and the highest SMH in G3. Conclusions: Agarose hydrogel application is a promising approach to treat early carious lesion. Further studies are needed to clarify the stability of agarose hydrogels in clinical application.

scholarly journals Analysis of stability problems via matrix Lyapunov functions

1990 ◽  
Vol 3 (4) ◽  
pp. 209-226 ◽  
Author(s):  
Anatoly A. Martynyuk
Keyword(s):  
Lyapunov Functions ◽  
Systems Of Nonlinear Equations ◽  
Matrix Functions ◽  
Singularly Perturbed Systems ◽  
Two Component System ◽  
Two Component ◽  
Lyapunov Matrix ◽  
Analysis Of Stability ◽  
The Stability ◽  
The Given

The stability of nonlinear systems is analyzed by the direct Lyapunov's method in terms of Lyapunov matrix functions. The given paper surveys the main theorems on stability, asymptotic stability and nonstability. They are applied to systems of nonlinear equations, singularly-perturbed systems and hybrid systems. The results are demonstrated by an example of a two-component system.

Stability Switches of a Class of Fractional-Delay Systems With Delay-Dependent Coefficients

2018 ◽  
Vol 13 (11) ◽  
Author(s):  
Xinghu Teng ◽  
Zaihua Wang
Keyword(s):  
Time Delay ◽  
Delay Systems ◽  
Jacobian Determinant ◽  
Stability Switches ◽  
Characteristic Roots ◽  
Fractional Delay ◽  
Analysis Of Stability ◽  
The Stability ◽  
Key Steps ◽  
Delay Dependent

Stability of a dynamical system may change from stable to unstable or vice versa, with the change of some parameter of the system. This is the phenomenon of stability switches, and it has been investigated intensively in the literature for conventional time-delay systems. This paper studies the stability switches of a class of fractional-delay systems whose coefficients depend on the time delay. Two simple formulas in closed-form have been established for determining the crossing direction of the characteristic roots at a given critical point, which is one of the two key steps in the analysis of stability switches. The formulas are expressed in terms of the Jacobian determinant of two auxiliary real-valued functions that are derived directly from the characteristic function, and thus, can be easily implemented. Two examples are given to illustrate the main results and to show an important difference between the fractional-delay systems with delay-dependent coefficients and the ones with delay-free coefficients from the viewpoint of stability switches.

Mathematical Analysis of Stability of a Spinning Disk Under Rotating, Arbitrarily Large Damping Forces

1996 ◽  
Vol 118 (4) ◽  
pp. 657-662 ◽  
Author(s):  
F. Y. Huang ◽  
C. D. Mote
Keyword(s):  
Periodic Solution ◽  
Parameter Space ◽  
Perturbation Technique ◽  
Stability Boundary ◽  
Rotating Disk ◽  
Stable Region ◽  
Damping Force ◽  
Analysis Of Stability ◽  
The Stability ◽  
Nontrivial Periodic Solution

Stability of a rotating disk under rotating, arbitrarily large damping forces is investigated analytically. Points possibly residing on the stability boundary are located exactly in parameter space based on the criterion that at least one nontrivial periodic solution is necessary at every boundary point. A perturbation technique and the Galerkin method are used to predict whether these points of periodic solution reside on the stability boundary, and to identify the stable region in parameter space. A nontrivial periodic solution is shown to exist only when the damping does not generate forces with respect to that solution. Instability occurs when the wave speed of a mode in the uncoupled disk, when observed on the disk, is exceeded by the rotation speed of the damping force relative to the disk. The instability is independent of the magnitude of the force and the type of positive-definite damping operator in the applied region. For a single dashpot, nontrivial periodic solutions exist at the points where the uncoupled disk has repeated eigenfrequencies on a frame rotating with the dashpot and the dashpot neither damps nor energizes these modes substantially around these points.

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