scholarly journals Does the line-to-line cementing technique of the femoral stem create an adequate cement mantle?

2020 ◽  
pp. 112070002093436
Author(s):  
Kirsti Sevaldsen ◽  
Otto S Husby ◽  
Øystein B Lian ◽  
Vigdis S Husby
Keyword(s):  
Femoral Stem ◽  
Cement Mantle ◽  
Cementing Technique ◽  
Early Failure ◽  
Advantages And Disadvantages ◽  
Press Fit ◽  
The Relationship ◽  
French Paradox

Background: The line-to-line cementing technique is proposed to create a press-fit in the femoral canal, which is contrary to modern cementing techniques. The term ‘French paradox’ has been used to describe the acceptable results associated with this technique. It has been suggested that the quality of the mantle may not be satisfactory, predisposing to early failure and aseptic loosening. Methods: The line-to-line cementing technique, where the femoral stem was oversized by 1 size compared to the broach, was compared to the standard cementing technique using corresponding sized broaches and stems, in 6 pairs of human cadaver femora with taper-slip design C-stems. Cement pressure was measured, and cement mantle thickness was analysed. A mixed effects model with random intercepts was used to examine the relationship between thickness of mantle and cementing technique and between pressure and cementing technique. Results: Line-to-line cementing results in significantly higher pressurisation for longer periods of time leading to better interdigitation but a thinner mantle in some areas. Conclusions: The results of this study describe the in-vitro advantages and disadvantages of the line-to-line cementing technique.

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.

Research on the Network Topology and Reliability of the Communication System in Smart Substations

2013 ◽  
Vol 765-767 ◽  
pp. 1757-1760
Author(s):  
Zhi Ming Wang ◽  
Xian Li Sun ◽  
Li Liu ◽  
Xiao Rui Zhang
Keyword(s):  
Network Topology ◽  
Network Performance ◽  
Vital Role ◽  
Network System ◽  
Entire System ◽  
Advantages And Disadvantages ◽  
Network Topologies ◽  
The Relationship ◽  
Smart Substation

Communication network plays a vital role in smart substations. Different network topology provides different network performance, while the quality of network performance directly impacts the reliability of the entire system. In view of the network topology of smart substations, this paper compares the advantages and disadvantages of different network topologies as well as different network schemes of substation layer and process layer, and also analyzes the relationship between the reliability of network system and network topology, which play an important role in establishing a reliable and efficient smart substation system.

scholarly journals Phytoestrogens for the Management of Endometriosis: Findings and Issues

2021 ◽  
Vol 14 (6) ◽  
pp. 569
Author(s):  
Xia Cai ◽  
Min Liu ◽  
Bing Zhang ◽  
Shao-Jie Zhao ◽  
Shi-Wen Jiang
Keyword(s):  
Animal Models ◽  
Primary Cultures ◽  
Life Quality ◽  
Human Intervention ◽  
Estrogenic Effects ◽  
Critical Issues ◽  
Intervention Trials ◽  
The Relationship

Endometriosis, a chronic disease characterized by recurrent pelvic pain and infertility, severely impacts the health and life quality of many women worldwide. Since phytoestrogens are commonly found in a variety of foods, and estrogen is a major pathological factor for the pathogenesis of endometriosis, their possible involvement cannot be ignored. This review summarizes data on the relationship between phytoestrogen intake and endometriosis risk, and analyzes the findings from in vitro experiments, rodent endometriotic models, and human intervention trials. While favorable results were often obtained from endometrial primary cultures and animal models for resveratrol, isoflavones and puerarin, only resveratrol showed promising results in human intervention trials. Critical issues concerning the current study efforts are discussed: the possible reasons beneath the discrepant observations of estrogenic/anti-estrogenic effects by phytoestrogens; the complicated interplays between phytoestrogens and endogenous estrogens; the shortage of currently used animal models; the necessity to apply reasonable doses of phytoestrogens in experiments. It is expected that the analyses would help to more properly assess the phytoestrogens’ effects on the endometriosis pathogenesis and their potential values for preventive or therapeutic applications.

scholarly journals Motion and its Effects on the Cement Mantle – A Biomechanical Analysis of Femoral Stem Displacement during Implant Cementation

2021 ◽  
pp. 23
Author(s):  
◽  
◽  
◽  
◽  
Keyword(s):  
Femoral Stem ◽  
Cement Mantle ◽  
Biomechanical Analysis ◽  
Original Position ◽  
Small Displacement ◽  
Pullout Strength ◽  
Rotational Displacement ◽  
Common Notion ◽  
Vitro Model

Background: It is a common notion that motion of a femoral component during cementation should be avoided as it may weaken the cement mantle. We created an in vitro model of cemented femoral components and subjected them to varying rotational motion during the cement curing process, to measure the effect on the pullout strength of the stem. Methods: 21 sawbones femurs were separated into four groups. The first group served as control and was cemented in a standard fashion. The remainder of the stems were divided into groups and subjected to angular rotational displacement within the cement mantle during curing . Anteroposterior and lateral radiographs were obtained of each model to evaluate for cement defects. Pullout strength testing was performed. Results: Despite rotational displacement, no cement defects were noted on imaging. The control stems showed an average pullout strength of 3735.79N. The experimental groups showed a trend for lower failure loads but it was not statistically significant (P=0.063). Of the 21 stems tested, three encountered cement mantle failure and associated stem pullout and the remainder failed by peripros-thetic fracture. Conclusion: Despite conventional thinking that rotational displacement during the cementing process leading to disruption of the cement mantle integrity, this was not borne out in our study. This should give surgeons confidence that in the set-ting of unintended rotational displacement of a femoral stem, returning the stem to its original position does not significantly compromise the integrity of the cement mantle or the pullout strength of the femoral implant. Small displacement of the femoral stem with prompt correction during cement curing does not cause evident cement mantle defects or a loss of femoral stem pullout strength.

scholarly journals On the Relationship between the Economic Indicators Basis and the Parameters of Managerial Decisions Development in an Organization

2019 ◽  
Vol 29 (1) ◽  
pp. 155-165
Author(s):  
Tatуana Alexandrova
Keyword(s):  
Economic Analysis ◽  
Advantages And Disadvantages ◽  
Managerial Decisions ◽  
Analysis Methodology ◽  
Eurasian Economic Union ◽  
Border Trade ◽  
Analytical Work ◽  
The Impact ◽  
The Relationship

The article deals with one of the key problems of the economic analysis methodology, i.e. with defining the basis of comparison of indicators and methods to obtain them. In the course of the research, the procedure of intercompany comparison was studied. The bases of comparison are defined; their advantages and disadvantages are singled out. The conditions under which it is advisable to use a certain basis of comparison when conducting economic analysis are formulated. Special attention is paid to the impact of the selected bases of comparison on the analysis reliability, as well as on the speed and quality of decision-making. The choice of alternative management solutions based on the use of different bases of indicators comparison is substantiated. Export activities of a Eurasian Economic Union enterprise involved in cross-border trade are analyzed as an example. The results of this research can be used in the analytical work of the organization to improve the reliability assessment of economic performance and the effectiveness of the managerial decisions development.

The technique of applying cluster analysis when Performing graduate qualification work by students St. Petersburg University of the Ministry of Internal Affairs of Russia

2020 ◽  
Vol 2020 (1) ◽  
pp. 208-217
Author(s):  
Aleksander Litvinenko ◽  
Lyudmila Bolshakova
Keyword(s):  
Cluster Analysis ◽  
University Students ◽  
Point Of View ◽  
Analysis Method ◽  
Advantages And Disadvantages ◽  
Analysis Methodology ◽  
Cluster Analysis Method ◽  
Relationship Of ◽  
The Relationship

The relevance of the topic have determined by needs of ensuring the quality of graduation qualifications by university students. This aim have to achieved, inter alia, using methods of mathematical and statistical analysis. The article discusses the practical application of the cluster analysis methodology by university students in the Graduation qualification work. The authors have analysed advantages and disadvantages of this method and determined the boundaries of its use. From a methodological point of view, it have interested to justify the boundaries of the Cluster analysis method application. Attention is to drawn the particular problems formulation the solution of which involves achieving the aim of cluster analysis. The authors describe the stages of clustering have identified with using the ascending hierarchical method. The article describes the basic rules and the sequence of using the STATISTICA package with the English version to solve the specific problem of clustering a large number of objects. As an example, the task of clustering eleven subjects of the Northwestern Subject of Russia in order to identify similar features of their innovative development. The authors emphasize the importance of using the method in terms of identifying the general properties of objects in allocated clusters. The regularities that describe the relationship of individual groups of objects are also substantial

The relationship between diet and the chemical composition of sheep faeces

2003 ◽  
Vol 2003 ◽  
pp. 150-150
Author(s):  
M. Afdal ◽  
D. I. Givens ◽  
C. Rymer ◽  
E. Owen ◽  
F. Mould
Keyword(s):  
Chemical Composition ◽  
Microbial Population ◽  
Evaluation Methods ◽  
Limited Information ◽  
Factors Affecting ◽  
Fermentative Activity ◽  
Using Data ◽  
The Relationship

The use of faecal inoculum in in vitro feed evaluation methods was examined by Balfe (1985). However, there is limited information concerning the chemical composition of faeces and factors affecting this. The chemical composition of faeces may reflect the microbial population and hence its fermentative activity. A knowledge of the faecal composition is essential as this affects the quality of faecal inoculum. The objective of this work was therefore to study the relationships between diet and the chemical composition of faeces using data obtained from sheep.

Cumulus cell features and nuclear chromatin configuration of in vitro matured canine COCs and the influence of in vivo serum progesterone concentrations of ovary donors

Zygote ◽  
2009 ◽  
Vol 17 (1) ◽  
pp. 79-91 ◽  
Author(s):  
B. A. Rodrigues ◽  
A. E. F. Silva ◽  
P. Rodriguez ◽  
L. F. Cavalcante ◽  
J. L. Rodrigues
Keyword(s):  
Cumulus Cell ◽  
Nuclear Chromatin ◽  
Serum Progesterone ◽  
Nuclear Maturation ◽  
Cumulus Oocyte Complex ◽  
Chromatin Configuration ◽  
The Relationship

SummaryPhenotype integrity is viewed as an indicator of cumulus–oocyte complex (COC) viability. The objectives of this study were: (a) to observe the influence of cumulus investment expansion on the nuclear chromatin configuration of canine oocytes matured in vitro; (b) to examine the relationship between cumulus cell (CC) expansion and its morphology after in vitro maturation (IVM); (c) to ascertain the influence of in vivo serum progesterone (SP) concentrations of ovary donors on oocyte nuclear maturation, CC phenotypes and degrees of CC expansion of in vitro matured COCs. After 48 h of IVM in modified TCM 199, CCs from grade 1 and 2 COCs were stained with propidium iodide. Oocyte chromatin configuration was visualized by Hoechst 33342 stain. Results showed that oocyte IVM was not influenced by degree of CC expansion (D1, D2 and D3) in COCs. From the CC types (C1, C2 and C3), number of C1 types was higher at D1 expansion and differed from those observed at D2 and D3 expansions. Additionally, rates of apoptosis in D1 CCs were lower than those observed in D2 CCs (p < 0.05). Oocyte nuclear maturation was not influenced by in vivo SP concentrations of ovary donors. On the other hand, D3 expansion prevailed in COCs from bitches at SP > 2.5 ng/ml (p < 0.001). Moreover, in vitro CC apoptosis was associated both with low (0–1 ng/ml) and with high (>5 ng/ml) in vivo SP levels. These findings indicate that morphology of CCs from in vitro matured dog oocytes gives valuable information on viability of COCs and could possibly be used as a parameter in predicting the quality of oocytes destined for in vitro fertilization (IVF) and their outcomes.

scholarly journals CHALLENGES OF INNOVATIVE ARCHITECTURE: EDUCATION AND PRACTICE

2018 ◽  
Vol 42 (1) ◽  
pp. 63-69
Author(s):  
Dalia AUGUSTINAITĖ
Keyword(s):  
Educational System ◽  
Education System ◽  
Present Situation ◽  
Thinking Skills ◽  
Architecture Education ◽  
Advantages And Disadvantages ◽  
Anthropogenic Environment ◽  
Innovative Thinking ◽  
The Relationship

The article analyzes the concept of innovative architecture, which is significant in developing the anthropogenic environment, explains the structural and systemic components that form it and the relations between them. The research focuses on the Lithuanian culture and the educational system of its architecture schools as a means contributing to the development of innovative thinking skills. On this basis, it explains what advantages and disadvantages of the education system in the country reflect the present practice of innovative architecture. At the end of the article, considering the present situation, suggestions are made on how to improve the quality of the relationship between education and practice.

Sign in / Sign up

Export Citation Format

Share Document