scholarly journals A Method for Prediction of Femoral Component of Hip Prosthesis Durability due to Aseptic Loosening by Using Coffin/Manson Fatigue Model

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Branislav Krivokapic ◽  
Zoran Blagojevic ◽  
Dora Selesi ◽  
Teodor Atanackovic ◽  
Stevan Pilipovic ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Aseptic Loosening ◽  
Hip Prosthesis ◽  
Real Life ◽  
Physical Activities ◽  
Femoral Offset ◽  
Model Estimate ◽  
Daily Physical Activities ◽  
High Degree ◽  
Prosthesis Durability

The purpose of this work is to develop a new model estimate of the fatigue life of a hip prosthesis due to aseptic loosening as a multifactorial phenomenon. The formula developed here is a three-parameter model based on Basquin’s law for fatigue, eccentric compression formula for the compressive stress and torsion in the prosthesis due to the horizontal components of the contact force. With our model, we can accurately predict the durability of a hip prosthesis due to the following four parameters: body weight, femoral offset, duration, and intensity of daily physical activities of a patient. The agreement of the prediction with the real life of the prosthesis, observed on 15 patients, is found to be adequate. Based on the formula derived for a particular implant, there was a high degree of concurrence between the model-predicted and actual values of aseptic loosening (durability) proved by the Mann–Whitney U test. By virtue of the validated model, it is possible to predict, quantitatively, the influence of various factors on the hip life. For example, we can conclude that a 10% decrease of a patient’s body mass, with all other conditions being the same, causes 5% increase of the hip fatigue life.

Analysis of 18F-FDG uptake patterns in PET for diagnosis of septic and aseptic loosening after total hip arthroplasty

2003 ◽  
Vol 42 (06) ◽  
pp. 234-239 ◽  
Author(s):  
T. Mumme ◽  
P. Reinartz ◽  
D. Wirtz ◽  
F. U. Niethard ◽  
U. Büll ◽  
...  
Keyword(s):  
Aseptic Loosening ◽  
Femoral Component ◽  
Hip Prosthesis ◽  
Prosthetic Infection ◽  
Clinical Value ◽  
Septic Loosening ◽  
Hip Prostheses ◽  
Fdg Uptake ◽  
Positron Emission ◽  
Painful Hip

Summary Aim: Identification of typical patterns for fluorodeoxyglucose (FDG) uptake in positron emission tomography (PET) to detect aseptic loosening of hip prosthesis (ace-tabular and/or femoral component) and prosthetic infection. Methods: 18 patients with painful hip prosthesis underwent PET using a dedicated full ring scanner after application of 200-300 MBq FDG. The interface between bone and surrounding soft tissue or bone as displayed on coronal slices was divided into 12 segments in accordance with the classifications of Delee and Gruen. FDG uptake in each of the segments was scored (0-3) by two independent observers. Intraoperative findings were regarded as the gold standard. Results: After surgical revision 14 acetabular components and 9 femoral components were found to be loose and prosthetic infection was present in 7 prostheses. Loosening of the acetabular component was correlated to enhanced uptake in the middle of the acetabular interface, while loosening of the femoral component was correlated to enhanced uptake in the proximal and middle segment of the lateral femoral interface and the proximal segment of the medial femoral interface. A similar pattern was found in prosthetic infection with high uptake along the middle portion of the lateral fe-moral interface. In 6 of 7 infected prostheses loosening of the acetabular and of the femoral component was present. Taking the typical uptake patterns as criteria for loosening and grade 3 uptake as an additional criterion for septic loosening the accuracy of PET imaging in the detection of loosening of the acetabular or the femoral component and of prosthetic infection was 72, 78 and 89%, respectively. Conclusion: This pilot study presents FDG-PET as a promising diagnostic tool for patients with painful hip prostheses. Its clinical value should be evaluated in a larger patient population.

The economic analysis of rationality in the tradition of Harvey Leibenstein

2020 ◽  
pp. 21-38
Author(s):  
Ivan V. Rozmainsky ◽  
Yulia I. Pashentseva
Keyword(s):  
Economic Analysis ◽  
Real Life ◽  
Informal Institutions ◽  
External Information ◽  
Urban Residents ◽  
The Future ◽  
Information Constraints ◽  
High Degree ◽  
Market Capitalism

The paper is devoted to the economic analysis of rationality in the tradition of Harvey Leibenstein: the authors perceive rationality as “calculatedness” when making decisions, while the degree of this “calculatedness” is interpreted as a variable. Thus, this approach does not correspond to the generally accepted neoclassical interpretation of rationality, according to which rationality is both full and constant. The authors believe that such a neoclassical approach makes too stringent requirements for the abilities of people. In real life, people do not behave like calculating machines. The paper discusses various factors limiting the degree of rationality of individuals. One group of factors is associated with external information constraints such as the complexity and extensiveness of information, as well as the uncertainty of the future. Another group of factors is related to informal institutions. In particular, the paper states that the system of planned socialism contributes to less rationality than the system of market capitalism. Thus, in the post-socialist countries, including contemporary Russia, one should not expect a high degree of rationality of the behavior of economic entities. The paper mentions, in particular, the factors of rationality caused by informal institutions, such as the propensity to calculate, the propensity to be independent when making decisions and the propensity to set goals. The authors also believe that people who live on their own are usually more rational than people who share a common household with someone else. This assumption is verified econometrically based on data on young urban residents collected by the authors. It turned out that the behavior of people included in this database, in general, corresponds to what the authors believed.

AN EFFICIENT APPROACH FOR THE THREE-DIMENSIONAL CONTAINER PACKING PROBLEM WITH PRACTICAL CONSTRAINTS

2004 ◽  
Vol 21 (03) ◽  
pp. 279-295 ◽  
Author(s):  
ZHIHONG JIN ◽  
KATSUHISA OHNO ◽  
JIALI DU
Keyword(s):  
Three Dimensional ◽  
Real Life ◽  
Packing Problem ◽  
Utilization Rate ◽  
Benchmark Problems ◽  
Rectangular Container ◽  
Efficient Packing ◽  
High Degree ◽  
Practical Constraints ◽  
Inherent Stability

This paper deals with the three-dimensional container packing problem (3DCPP), which is to pack a number of items orthogonally onto a rectangular container so that the utilization rate of the container space or the total value of loaded items is maximized. Besides the above objectives, some other practical constraints, such as loading stability, the rotation of items around the height axis, and the fixed loading (unloading) orders, must be considered for the real-life 3DCPP. In this paper, a sub-volume based simulated annealing meta-heuristic algorithm is proposed, which aims at generating flexible and efficient packing patterns and providing a high degree of inherent stability at the same time. Computational experiments on benchmark problems show its efficiency.

The importance of diversified physical activities in early childhood for later fundamental movement skills and physical activity level: a seven-year longitudinal study

2021 ◽  
Author(s):  
Paulina S. Melby ◽  
Peter Elsborg ◽  
Glen Nielsen ◽  
Rodrigo A. Lima ◽  
Peter Bentsen ◽  
...  
Keyword(s):  
Physical Activity ◽  
Structural Equation Models ◽  
Experimental Studies ◽  
Physical Activities ◽  
School Intervention ◽  
Activity Level ◽  
Life Course Perspective ◽  
Movement Skills ◽  
Fundamental Movement Skills ◽  
Daily Physical Activities

Abstract Background: Research indicates that childhood fundamental movement skills (FMS) can predict physical activity (PA) later in life and it has been argued that frequently engaging in a wide diversity of physical activities will eventually improve children’s FMS. However, no longitudinal or experimental studies have confirmed this hypothesis. The aims of this study are to investigate the longitudinal associations between diversified physical activities at age six and later FMS and PA (age nine and 13). Furthermore, we explore to what extent the longitudinal association between diversified physical activity and PA is mediated by FMS.Methods: Longitudinal data from the Copenhagen School Intervention Studywere used for this analysis, where 704 participated (69% response rate). Diversified physical activity (self-reported), FMS (The Körperkoordinationstest für Kinder battery of postural stability and locomotor skills) and PA (accelerometer) were assessed in the children at age six, age nine and age 13. A total of 991 participated in at least one of the measure years. Two structural equation models were constructed, with diversified physical activity at age six and FMS and PA at age nine as predictors of PA and FMS at age 13. Results: The data from both models demonstrated good model fit. Diversified physical activity at six years of age was significantly associated with physical activity and FMS at age 13, when adjusting for sex, age, intervention, weight, height, and previous levels of PA and FMS. Diversified physical activity at age six was also positively associated with PA and FMS at age nine, which were, in turn, positively related to PA at age 13 but to a lesser degree than diversified PA at age six. The association between diversified physical activity at age six and PA at age 13 was not mediated by FMS at age nine. Conclusions: The results of this study indicate that diversified physical activity at age six is important for the development of FMS and PA in adolescence. Increasing the diversity of children’s daily physical activities, not only the amount and intensity, seems important for future PA behavior and thereby health promotion in a life course perspective.

scholarly journals Studies on the Decrease Mechanisms of Typical Complex Networks

2021 ◽  
Author(s):  
Yuhu Qiu ◽  
Tianyang Lyu ◽  
Xizhe Zhang ◽  
Ruozhou Wang
Keyword(s):  
Average Length ◽  
Shortest Paths ◽  
Real Life ◽  
Network Models ◽  
Small World ◽  
Clustering Coefficient ◽  
Network Growth ◽  
Scale Free ◽  
Complex Network Models ◽  
High Degree

Network decrease caused by the removal of nodes is an important evolution process that is paralleled with network growth. However, many complex network models usually lacked a sound decrease mechanism. Thus, they failed to capture how to cope with decreases in real life. The paper proposed decrease mechanisms for three typical types of networks, including the ER networks, the WS small-world networks and the BA scale-free networks. The proposed mechanisms maintained their key features in continuous and independent decrease processes, such as the random connections of ER networks, the long-range connections based on nearest-coupled network of WS networks and the tendency connections and the scale-free feature of BA networks. Experimental results showed that these mechanisms also maintained other topology characteristics including the degree distribution, clustering coefficient, average length of shortest-paths and diameter during decreases. Our studies also showed that it was quite difficult to find an efficient decrease mechanism for BA networks to withstand the continuous attacks at the high-degree nodes, because of the unequal status of nodes.

PENERAPAN AKTIVITAS FUNGSIONAL REKREASI PADA MASA NEW NORMAL UNTUK MENJAGA KESEHATAN LANJUT USIA

2020 ◽  
Vol 1 (1) ◽  
pp. 62
Author(s):  
Ipa Sari Kardi ◽  
Nasri Nasri ◽  
Ibrahim Ibrahim ◽  
Yahya Eko Nopiyanto
Keyword(s):  
Well Being ◽  
The Elderly ◽  
Functional Change ◽  
Normal Weight ◽  
Physical Activities ◽  
New Normal ◽  
Functional Activities ◽  
Technological Advances ◽  
Normal Period ◽  
Daily Physical Activities

Background: Structural and functional change in the elderly is a process that cannot be stopped, but can be managed, so that it can inhibit the aging process. Technological advances in the digital era 4.0 coupled with the Covid-19 pandemic at the beginning of 2020 make someone, especially the elderly, less mobile. One of the actions that can be taken is implementing recreational functional activities, which are physical activities that are carried out happily with other people, such as family or community. This action is one of the safe and effective ways to help maintain the health of the elderly during the new normal period, so that the elderly are still able to carry out daily physical activities, stay healthy, productive and happy. Recreational functional activities play an important role in the well-being of the elderly and in improving the quality of life of all ages, including the elderly. Purpose: This community service aims to introduce a variety of functional activities that can entertain and delight the elderly. Methods: The method used was counseling and the application of recreational functional activities. Results: Based on the results of blood pressure examinations, it was found that the elderly who had hypertension were (73%) and normal (27%), the BMI measurement showed less weight (20%), normal weight (13%), over weight (20%) , OB I (27%) and OB II (20%). After applying recreational functional activities, there is a good response from the elderly. The elderly feel happier, experience and increase knowledge about simple movements that can stimulate the physical, psychological and social health of the elderly, even if only around the place of residence.

The Influencing Factors and Assessment Model of Fatigue Life of Shaft

2013 ◽  
Vol 772 ◽  
pp. 427-431
Author(s):  
Yong Zhuang Yuan
Keyword(s):  
Comparative Analysis ◽  
Fatigue Life ◽  
Influencing Factors ◽  
Real Life ◽  
Product Lifecycle Management ◽  
Assessment Model ◽  
Product Lifecycle ◽  
Predicting Model ◽  
Design Life ◽  
Lifecycle Management

Predicting the life of part is emphasis base of Product Lifecycle Management, and is emphasis progress of modern product design. By exact and full analyze the influencing factors of real life of shaft, contribute to real life and design life coincidence of shaft. It can decrease property damage with product ahead of schedule failure. By comparative analysis and analytical method researched the influencing factors of shaft in used . The life predicting model of reality use is discussed and amended at present. It draws a reasonable predicting model of fatigue life. The model includes influencing factors of all in actual and decrease the error of predicting life compare with the life of real. It will establish the base of design of anti-fatigue of shaft.

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