scholarly journals Wear of ultra-high molecular weight polyethylene (UHMWPE) in total knee prostheses: A review of key influences

2000 ◽  
Vol 214 (4) ◽  
pp. 349-359 ◽  
Author(s):  
T M McGloughlin ◽  
A G Kavanagh
Keyword(s):  
Testing Machine ◽  
Wear Testing ◽  
Knee Prostheses ◽  
Wear Process ◽  
Testing Procedures ◽  
Total Knee ◽  
The University ◽  
The Impact

The formation and development of wear is now widely accepted as one of the major concerns in the long-term survivorship of contemporary knee prostheses in vivo. This review examines the role of surface topography, third-body debris, load, contact mechanics and material quality in the wear process. Some of the kinematic and physiological issues that need to be modelled in the development of wear testing regimes for evaluation of material combinations and geometrical combinations in total knee implant designs are considered. Wear testing procedures and some of the results from wear tests are discussed and the need to consider the impact of rolling and sliding in the study of wear in total knee components is highlighted. The dominant wear mechanisms that occur in vivo are identified and the role of these mechanisms is currently being examined experimentally at the University of Limerick wear testing machine.

Wear of Artificial Joint Materials III

1981 ◽  
Vol 10 (3) ◽  
pp. 137-142 ◽  
Author(s):  
R W Treharne ◽  
R W Young ◽  
S R Young
Keyword(s):  
Wear Rate ◽  
Contact Area ◽  
Inverse Relationship ◽  
Wear Testing ◽  
Artificial Joint ◽  
Knee Prostheses ◽  
Wear Rates ◽  
Knee Simulator ◽  
Total Knee

This paper describes a new method for testing total knee prostheses under simulated in vivo conditions. Previous knee simulator work has been summarized and described. The major variables of testing are also described in detail. The results of wear testing five types of knee prostheses were that the wear rate was nearly an inverse relationship with contact area— knees with a higher contact area had lower wear rates.

Zmiana modelu zarządzania i nadzoru nad jakością kształcenia w szkolnictwie wyższym. Perspektywa doświadczeń Republiki Federalnej Niemiec

2020 ◽  
pp. 137-149
Author(s):  
Krzysztof Szewior
Keyword(s):  
Quality Of Education ◽  
Research Approach ◽  
University Management ◽  
Strategic Partner ◽  
Higher Education Reforms ◽  
The University ◽  
The Impact ◽  
Desk Research

The author focuses on the manner and effects of German higher education reforms that have changed the model of university management. The point of reference is the quality of education and its role, how universities ensure it, and how it is verified through evaluation and accreditation. These elements divide the article into two parts: a part about quality and a part about evaluation and accreditation. The analysis includes the impact of global processes and Europeanization. The research approach is characteristic for public policies, sciences of management and quality. The theories used in this article: the theory of systems and neo-institutionalism, as well as perspectives: the university as an active strategic partner, entrepreneurial university, the third role of universities. The publication is based on desk research and on the analysis of processes.

scholarly journals Impact of the COVID-19 pandemic and its related psychological effect on orthopedic surgeries conducted in different types of hospitals in Taiwan

2021 ◽  
Vol 29 (1) ◽  
pp. 230949902199607 ◽  
Author(s):  
Chia-Lung Shih ◽  
Peng-Ju Huang ◽  
Hsuan-Ti Huang ◽  
Chung-Hwan Chen ◽  
Tien-Ching Lee ◽  
...  
Keyword(s):  
Community Hospital ◽  
University Hospital ◽  
Total Knee Arthroplasties ◽  
Peak Period ◽  
Number Of Patients ◽  
Total Knee ◽  
Investigation Period ◽  
Orthopedic Diseases ◽  
The University ◽  
The Impact

Aim: Taiwan’s response to the coronavirus disease 2019 (COVID-19) differed in that it successfully prevented the spread without having to shutdown or overburden medical services. Patients’ fear regarding the pandemic would be the only reason to reduce surgeries, so Taiwan could be the most suitable place for research on the influence of psychological factors. This study aimed to assess the impact of patients’ fear on orthopedic surgeries in Taiwan amid the peak period of the COVID-19 pandemic. Patients and Methods: The investigation period included the COVID-19 pandemic (March 2020 to April 2020) and the corresponding period in the previous year. The following data on patients with orthopedic diseases were collected: outpatient visits, hospital admission, and surgical modalities. Results: The COVID-19 pandemic led to a 22%–29% and 20%–26% reduction in outpatients, 22%–27% and 25%–37% reduction in admissions, and 26%–35% and 18%–34% reduction in surgeries, respectively, at both hospitals. The weekly mean number of patients was significantly smaller during the COVID-19 pandemic for all types of surgery and elective surgeries at the university hospital, and for all types of surgery, elective surgeries, and total knee arthroplasties at the community hospital. Further, patients visiting the community hospital during the pandemic were significantly younger, for all types of surgery, elective surgeries, and total knee arthroplasties. Conclusions: The reduction in orthopedic surgeries in Taiwan’s hospitals during COVID-19 could be attributed to patients’ fear. Even without restriction, the pandemic inevitably led to a reduction of about 20%–30% of the operation volume.

scholarly journals Entrepreneurial intention: An analysis of the role of Student-Led Entrepreneurial Organizations

2021 ◽  
Author(s):  
Giuliano Sansone ◽  
Elisa Ughetto ◽  
Paolo Landoni
Keyword(s):  
Entrepreneurial Intention ◽  
Policy Implications ◽  
Policy Makers ◽  
Student Entrepreneurship ◽  
Entrepreneurial Organizations ◽  
Entrepreneurial Activities ◽  
The University ◽  
The Impact ◽  
The Empirical Analysis

AbstractAlthough a great deal of attention has been paid to entrepreneurship education, only a few studies have analysed the impact of extra-curricular entrepreneurial activities on students’ entrepreneurial intention. The aim of this study is to fill this gap by exploring the role played by Student-Led Entrepreneurial Organizations (SLEOs) in shaping the entrepreneurial intention of their members. The analysis is based on a survey that was conducted in 2016 by one of the largest SLEOs in the world: the Junior Enterprises Europe (JEE). The main result of the empirical analysis is that the more time students spent on JEE and the higher the number of events students attended, the greater their entrepreneurial intention was. It has been found that other important drivers also increase students’ entrepreneurial intention, that is, the Science and Technology field of study and the knowledge of more than two foreign languages. These results confirm that SLEOs are able to foster students’ entrepreneurial intention. The findings provide several theoretical, practical and public policy implications. SLEOs are encouraged to enhance their visibility and lobbying potential in order to be recognized more as drivers of student entrepreneurship. In addition, it is advisable for universities and policy makers to support SLEOs by fostering their interactions with other actors operating in the entrepreneurial ecosystem, who promote entrepreneurship and technology transfer activities. Lastly, this paper advises policy makers to assist SLEOs’ activities inside and outside the university context.

The Role of Financing Higher Education in Nigerian Universities in Achieving Sustainable Development

2021 ◽  
Vol 4 (4) ◽  
pp. 551-578
Author(s):  
Samir Mohamad Hassan
Keyword(s):  
Higher Education ◽  
Sustainable Development ◽  
Private University ◽  
Accurate Information ◽  
Community Initiatives ◽  
Higher Education Financing ◽  
The University ◽  
Financing Higher Education ◽  
The Impact

The current study aims to identify the role of financing higher education in Nigerian universities in the state of Kano and its impact on sustainable development. The study problem lies in the low funding of higher education in Nigerian universities, which will negatively affect the sustainability of higher education and sustainable development. The importance of the study is highlighted by highlighting the importance of financing higher education in Nigerian universities and the sources of obtaining this funding as one of the most important factors through which students can complete their studies. The study followed the qualitative approach with the aim of obtaining more accurate information about traditional higher education financing sources and its impact on the sustainability of education and achieving sustainable development. The study population reached the number of three Nigerian universities, which are a governmental, federal and private university, to learn about the impact of financing higher education in Nigerian universities on sustainable development. The sample of the study was about three out of five of those responsible for financing higher education in Nigerian universities. Also, the study followed unstructured or open interviews in order to obtain more information about financing higher education and whether or not it is suitable for the idea of a monetary endowment. The results of the study showed that the sources of financing for higher education in traditional Nigerian universities are varied, including what can be obtained through the endowment and donations fund that can be made through community initiatives, and the results of the study also indicated that the idea of a monetary endowment faces great challenges in its application, so the idea is subject to acceptance and rejection. According to the nature of the university and the nature of the subjects taught. The study recommended the necessity of expanding the study of the impact of financing higher education in Nigerian universities by expanding the scope of study to include all Nigerian states.

Role of Servicescape on Student Institution Choice

2021 ◽  
pp. 271-278
Author(s):  
Ravi Kumar J S ◽  
T. Narayana Reddy ◽  
Syed Mohammad Ghouse
Keyword(s):  
Student Choice ◽  
Prospective Students ◽  
University Environment ◽  
University Marketing ◽  
Sociological Factors ◽  
Emotional Factors ◽  
Physical Environments ◽  
The University ◽  
The Impact

In recent years there has been increased discussion of the subjective, emotional and sociological factors influencing student choice of university. However, there is a dearth of information exploring what constitutes these feelings. This exploratory paper uses the conceptual model of the servicescape to provide insight into the emotional factors driving student choice. In-depth interviews with prospective students revealed that first impressions really do count. Students are deterred by poor physical environments and excited by enthusiastic staff and students. Most significantly, the study revealed the necessity of a restorative servicescape to provide both a sense of escape and feeling of belonging. This paper contributes to broadening the application of the servicescape model and to a greater understanding of the impact of the environment on prospective students, and creates an opportunity to inform policy by providing university marketing decision makers with a better understanding of what constitutes the university environment and what makes it appealing to prospective students.

Effect of Gait on Patellofemoral Mechanics

2008 ◽  
Author(s):  
Jeffrey E. Bischoff ◽  
Justin S. Hertzler
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Clinical Studies ◽  
Patellofemoral Joint ◽  
Knee Kinematics ◽  
Component Design ◽  
Total Knee ◽  
The Impact ◽  
Reconstructed Knee

Computational modeling of the reconstructed knee is an important tool in designing components for maximum functionality and life. Utilization of boundary conditions consistent with in vivo gait loading in such models enables predictions of knee kinematics and polyethylene damage [1–4], which can then be used to optimize component design. Several recent clinical studies have focused on complications associated with the patellofemoral joint [5–6], highlighting the need to better understand the mechanics of this compartment of total knee arthroplasty (TKA). This study utilizes a computational model to characterize the impact of gait loading on the mechanics of the patella in TKA.

scholarly journals Evaluation of Mechanical, Microstructures and Wear Behaviours of Aluminium Alloy Reinforced with Mussel Shell Powder for Automobile Applications

2021 ◽  
Vol 67 (1-2) ◽  
pp. 27-35
Author(s):  
Idawu Yakubu Suleiman ◽  
Auwal Kasim ◽  
Abdullahi Tanko Mohammed ◽  
Munir Zubairu Sirajo
Keyword(s):  
Mechanical Properties ◽  
Aluminium Alloy ◽  
Automobile Industry ◽  
Testing Machine ◽  
Wear Testing ◽  
Wear Behaviour ◽  
Mussel Shell ◽  
The Matrix ◽  
The Impact ◽  
Shell Powder

This paper aims to investigate the mechanical (tensile, hardness, impact, elongation), microstructure and wear behaviours of aluminium alloy reinforced with mussel shell powder (MSP) at different weight percentages (0 wt. % to 15 wt. %) at 3 wt. % interval. The mussel shell powder was characterized by X-ray fluorescence (XRF). The matrix and the composites’ morphology were studied using a scanning electron microscope attached with energy dispersive spectroscopy for the distribution of mussel shell powder particles within the matrix. The wear behaviour of the alloy and composites produced at various reinforcements were carried out using a Taber abrasion wear-testing machine. The XRF showed the compositions of MSP to contain calcium oxide (95.70 %), silica (0.83 %) and others. Mechanical properties showed that tensile values increase with increases in MSP, hardness value increases from 6 wt. % to 15 wt. % of MSP. The impact energy decreased from 42.6 J at 3 wt. % to 22.6 J at 15 wt. %; the percentage elongation also decreased from 37.4 % at 3 wt. % to 20.5 % at 15 wt. % MSP, respectively. The bending stress results increase with increases in the percentage of reinforcement. The morphologies revealed that uniform distribution of MSP within the matrix resulted to improvement in mechanical properties. The wear resistance of the composites increases with increase in the applied load and decreases with increases in the weight percentage of MSP and can be used in the production of brake pads and insulators in the automobile industry.

scholarly journals HYPOXIA AND REPRODUCTIVE HEALTH: The presence and role of hypoxia in the endometrium

Reproduction ◽  
2021 ◽  
Vol 161 (1) ◽  
pp. F1-F17
Author(s):  
Rocío Martínez-Aguilar ◽  
Lucy E Kershaw ◽  
Jane J Reavey ◽  
Hilary O D Critchley ◽  
Jacqueline A Maybin
Keyword(s):  
Current Knowledge ◽  
Abnormal Uterine Bleeding ◽  
Future Research ◽  
Hypoxic Episode ◽  
Optimal Function ◽  
Pros And Cons ◽  
The Impact ◽  
Review Current

The endometrium is a multicellular tissue that is exquisitely responsive to the ovarian hormones. The local mechanisms of endometrial regulation to ensure optimal function are less well characterised. Transient physiological hypoxia has been proposed as a critical regulator of endometrial function. Herein, we review the literature on hypoxia in the non-pregnant endometrium. We discuss the pros and cons of animal models, human laboratory studies and novel in vivo imaging for the study of endometrial hypoxia. These research tools provide mounting evidence of a transient hypoxic episode in the menstrual endometrium and suggest that endometrial hypoxia may be present at the time of implantation. This local hypoxia may modify the inflammatory environment, influence vascular remodelling and modulate endometrial proliferation to optimise endometrial function. Finally, we review current knowledge of the impact of this hypoxia on endometrial pathologies, with a focus on abnormal uterine bleeding. Throughout the manuscript areas for future research are highlighted with the aim of concentrating research efforts to maximise future benefits for women and society.

scholarly journals Cerebrospinal Fluid Pulsation Stress Promotes the Angiogenesis of Tissue-Engineered Laminae

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Linli Li ◽  
Yiqun He ◽  
Han Tang ◽  
Wei Mao ◽  
Haofei Ni ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Cerebrospinal Fluid ◽  
Engineering Technology ◽  
Expression Levels ◽  
Fluid Pulsation ◽  
Endothelial Growth Factor ◽  
The Impact

Background. Angiogenesis is a prerequisite step to achieve the success of bone regeneration by tissue engineering technology. Previous studies have shown the role of cerebrospinal fluid pulsation (CSFP) stress in the reconstruction of tissue-engineered laminae. In this study, we investigated the role of CSFP stress in the angiogenesis of tissue-engineered laminae. Methods. For the in vitro study, a CSFP bioreactor was used to investigate the impact of CSFP stress on the osteogenic mesenchymal stem cells (MSCs). For the in vivo study, forty-eight New Zealand rabbits were randomly divided into the CSFP group and the Non-CSFP group. Tissue-engineered laminae (TEL) was made by hydroxyapatite-collagen I scaffold and osteogenic MSCs and then implanted into the lamina defect in the two groups. The angiogenic and osteogenic abilities of newborn laminae were examined with histological staining, qRT-PCR, and radiological analysis. Results. The in vitro study showed that CSFP stress could promote the vascular endothelial growth factor A (VEGF-A) expression levels of osteogenic MSCs. In the animal study, the expression levels of angiogenic markers in the CSFP group were higher than those in the Non-CSFP group; moreover, in the CSFP group, their expression levels on the dura mater surface, which are closer to the CSFP stress stimulation, were also higher than those on the paraspinal muscle surface. The expression levels of osteogenic markers in the CSFP group were also higher than those in the Non-CSFP group. Conclusion. CSFP stress could promote the angiogenic ability of osteogenic MSCs and thus promote the angiogenesis of tissue-engineered laminae. The pretreatment of osteogenic MSC with a CSFP bioreactor may have important implications for vertebral lamina reconstruction with a tissue engineering technique.

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