scholarly journals Variation of the femoral J-Curve in the native knee

10.29007/5k32 ◽  
2020 ◽  
Author(s):  
Sonja A. G. A. Grothues ◽  
Malte Asseln ◽  
Klaus Radermacher

The J-Curve in the native knee as well as the femoral component’s J-Curve after total knee arthroplasty are known to have a high influence on kinematics. Furthermore, the J-Curve’s shape affects ligament strain and tension and consequently already slight changes may strongly alter knee forces and stability. To optimize current implants’ J-Curve design with regard to the population’s morphology, information about the main sources of contour variation is necessary.In this study, a principal component analysis (PCA) was performed on the medial and lateral femoral J-Curves of 90 cadavers without history of osteoarthritis. The J-Curves’ mean shapes were further investigated by geometric parameter analysis and effect sizes were calculated for the first three principal components (PCs). In addition, a combined PCA for both sides was performed and evaluated qualitatively. The results were compared with the variation in standard implants’ J-Curve shape.The isolated PCA of medial and lateral J-Curves resulted in PCs involving changes in contour orientation, arc length, scaling and circularity. The combined PCA of both sides resulted in PCs comprising combinations of the individual variations together with changes in relative position. In contrast, the qualitative evaluation of J-Curves from 2 different standard implant systems revealed no visible changes in shape but only changes in size.Limitations of this study were the restriction to a 2-dimensional contour derivation and the sole consideration of the femoral contours. Nevertheless, the sagittal variability in the medial, lateral and combined femoral J-Curves should be considered in implant design.


2021 ◽  
Vol 11 (7) ◽  
pp. 592
Author(s):  
Sonja A. G. A. Grothues ◽  
Klaus Radermacher

The native femoral J-Curve is known to be a relevant determinant of knee biomechanics. Similarly, after total knee arthroplasty, the J-Curve of the femoral implant component is reported to have a high impact on knee kinematics. The shape of the native femoral J-Curve has previously been analyzed in 2D, however, the knee motion is not planar. In this study, we investigated the J-Curve in 3D by principal component analysis (PCA) and the resulting mean shapes and modes by geometric parameter analysis. Surface models of 90 cadaveric femora were available, 56 male, 32 female and two without respective information. After the translation to a bone-specific coordinate system, relevant contours of the femoral condyles were derived using virtual rotating cutting planes. For each derived contour, an extremum search was performed. The extremum points were used to define the 3D J-Curve of each condyle. Afterwards a PCA and a geometric parameter analysis were performed on the medial and lateral 3D J-Curves. The normalized measures of the mean shapes and the aspects of shape variation of the male and female 3D J-Curves were found to be similar. When considering both female and male J-Curves in a combined analysis, the first mode of the PCA primarily consisted of changes in size, highlighting size differences between female and male femora. Apart from changes in size, variation regarding aspect ratio, arc lengths, orientation, circularity, as well as regarding relative location of the 3D J-Curves was found. The results of this study are in agreement with those of previous 2D analyses on shape and shape variation of the femoral J-Curves. The presented 3D analysis highlights new aspects of shape variability, e.g., regarding curvature and relative location in the transversal plane. Finally, the analysis presented may support the design of (patient-specific) femoral implant components for TKA.



2014 ◽  
Vol 6 ◽  
pp. IJIS.S13029
Author(s):  
Sangita Mitra ◽  
Rupa Harsha ◽  
Niladri Hazra ◽  
Abhijit Mazumdar

The assessment of the morphological and reproductive features of white rice leafhopper Cofana spectra (Distant) was carried out using selected characters that bear importance in determining the fitness at the individual and population levels. Morphometric measurements of the individuals reared in the laboratory as normal and stylopized with the strepsipteran parasitoid, Halictophagus australensis Perkins, were recorded and analyzed. A t-test was performed to justify whether parasitization by H. australensis affected the traits. Correlations and regression analyses were carried out to deduce the difference in relative importance of the morphological features in the life history of C. spectra and their variation because of stylopization by H. australensis. A principal component analysis (PCA) was applied on the morphometric data to further substantiate the difference observed in the traits. In case of stylopized white leafhopper (WLH), fecundity was inhibited almost completely irrespective of seasons. The effect of stylopization on the life history traits of C. spectra has been noted that supports its possible use in biocontrol.



2021 ◽  
Vol 342 ◽  
pp. 11003
Author(s):  
Cristina Adriana Dahm Tataru

Temporo-mandibular joint disorders represent an issue of particular importance for the health and proper functioning of the dentomaxillary systhem. Research conducted in this paper aims to analyse biomechanics and temporomandibular joint among patients who, one the one side have implants placed over a history of joint disease, emphasising developments along post-interventio. On the oder side, patients without a history of joint pathology were recieving implant prosthesis. The study includes a total of 138 subjects (N=138), age between 18 and 64 years, with lateral edentulous that have been applied to dental implants and made overdenture. All patients are clinically healthy. The research methods comprise systematic observation and clinical trial, applied to two groups: one of study and one of control. Biomechanical principles can not guarantee the avoidance in the case of biopathological response to overload (respectively outer-implant bone resorption). These will not lead to the prognostic for all types of prosthetic overstructures with implant support, because the individual variations of bone resistance can not be apropriatly measured. The present paper is an applied research which is designed to solve short term problems, in order to contribute to the development of an interdisciplinary scientific field.



Crisis ◽  
2016 ◽  
Vol 37 (4) ◽  
pp. 265-270 ◽  
Author(s):  
Meshan Lehmann ◽  
Matthew R. Hilimire ◽  
Lawrence H. Yang ◽  
Bruce G. Link ◽  
Jordan E. DeVylder

Abstract. Background: Self-esteem is a major contributor to risk for repeated suicide attempts. Prior research has shown that awareness of stigma is associated with reduced self-esteem among people with mental illness. No prior studies have examined the association between self-esteem and stereotype awareness among individuals with past suicide attempts. Aims: To understand the relationship between stereotype awareness and self-esteem among young adults who have and have not attempted suicide. Method: Computerized surveys were administered to college students (N = 637). Linear regression analyses were used to test associations between self-esteem and stereotype awareness, attempt history, and their interaction. Results: There was a significant stereotype awareness by attempt interaction (β = –.74, p = .006) in the regression analysis. The interaction was explained by a stronger negative association between stereotype awareness and self-esteem among individuals with past suicide attempts (β = –.50, p = .013) compared with those without attempts (β = –.09, p = .037). Conclusion: Stigma is associated with lower self-esteem within this high-functioning sample of young adults with histories of suicide attempts. Alleviating the impact of stigma at the individual (clinical) or community (public health) levels may improve self-esteem among this high-risk population, which could potentially influence subsequent suicide risk.



Author(s):  
Rachel Ablow

The nineteenth century introduced developments in science and medicine that made the eradication of pain conceivable for the first time. This new understanding of pain brought with it a complex set of moral and philosophical dilemmas. If pain serves no obvious purpose, how do we reconcile its existence with a well-ordered universe? Examining how writers of the day engaged with such questions, this book offers a compelling new literary and philosophical history of modern pain. The book provides close readings of novelists Charlotte Brontë and Thomas Hardy and political and natural philosophers John Stuart Mill, Harriet Martineau, and Charles Darwin, as well as a variety of medical, scientific, and popular writers of the Victorian age. The book explores how discussions of pain served as investigations into the status of persons and the nature and parameters of social life. No longer conceivable as divine trial or punishment, pain in the nineteenth century came to seem instead like a historical accident suggesting little or nothing about the individual who suffers. A landmark study of Victorian literature and the history of pain, the book shows how these writers came to see pain as a social as well as a personal problem. Rather than simply self-evident to the sufferer and unknowable to anyone else, pain was also understood to be produced between persons—and even, perhaps, by the fictions they read.



2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Esethu Monakali

This article offers an analysis of the identity work of a black transgender woman through life history research. Identity work pertains to the ongoing effort of authoring oneself and positions the individual as the agent; not a passive recipient of identity scripts. The findings draw from three life history interviews. Using thematic analysis, the following themes emerge: institutionalisation of gender norms; gender and sexuality unintelligibility; transitioning and passing; and lastly, gender expression and public spaces. The discussion follows from a poststructuralist conception of identity, which frames identity as fluid and as being continually established. The study contends that identity work is a complex and fragmented process, which is shaped by other social identities. To that end, the study also acknowledges the role of collective agency in shaping gender identity.



2017 ◽  
Vol 24 (2) ◽  
pp. 451-469
Author(s):  
Gudrun Lier ◽  
Anna Fransina Van Zyl

The study of Aramaic Bible translations (Targumim) continues to be a valuable source of information, not only for uncovering the history of biblical interpretation but also for providing insights for the study of linguistics and translation techniques. In comparison with work done on the Pentateuchal Targumim and Targum Former Prophets, research on the individual books of Targum Minor Prophets has been scant. By providing an overview of selected source material this review seeks (i) to provide incentives for more focussed studies in the field of Targum Minor Prophets and (ii) to motivate new integrated research approaches which are now made possible with the assistance of highly developed software programmes.



2020 ◽  
Vol 29 (1) ◽  
pp. 33-57
Author(s):  
V.M. Loskot ◽  
G.B. Bakhtadze

Geographic distribution and habitat preferences of Saxicola rubicola rubicola (Linnaeus, 1766), S. maurus variegatus (S.G. Gmelin, 1774), and S. m. armenicus (Stegman, 1935) inhabiting the Caucasian Isthmus and adjacent areas are described in detail. We examined the individual, sexual, age, seasonal and geographical variations of seven main diagnostic features of both plumage and morphometrics (exactly, the length of wing and tail) using 381 skin specimens. Substantially improved diagnoses of S. m. variegatus and S. m. armenicus are provided. After a thorough examination of the materials and history of the expedition of Samuel Gmelin in 1768–1774, and his description of Parus variegatus, it was concluded that the type locality of this taxon was the vicinity of Shamakhi in Azerbaijan not Enzeli in North-Western Turkey. It is also shown the fallacy of the recently proposed attribution of the holotype of the northern subspecies S. m. variegatus to the southern taxon S. m. armenicus and synonymisation of these names, as well as the replacement of the name S. m. variegatus by its junior synonym S. m. hemrichii Ehrenberg, 1833 for the northern subspecies.



Author(s):  
Dr.Prachyakorn Chaiyakot ◽  
Wachara Chaiyakhet ◽  
Dr.Woraluck Lalitsasivimol ◽  
Dr.Siriluck Thongpoon

Songkhla Lake Basin has a long history of at least 6,000 years and has a wide variety of tourism resources including nature, history, beliefs, culture and various traditions of the local people. It covers 3 provinces, the whole area of Phatthalung, 12 districts of Songkhla and 2 districts of Nakhon Si Thammarat Province. It has an area of approximately 8,727 square kilometers. There are many tourist attractions because the basin has a long history through different eras, natural, historic, ancient sites, and the culture of the local people. In 2018, both Thai and foreign tourists visited Songkhla and Phatthalung, which is the main area of Songkhla Lake Basin. The total number of tourists that came was 7,628,813 and 1,641,841 and an income of 68,252.64 and 3,470.96 million baht was generated from each province, respectively (Ministry of Tourism and Sports, 2020). Although Songkhla Lake Basin has various tourist attractions, the promotion of tourism with the involvement of government agencies in the past mainly focused on promoting tourism along with the tourist attractions rather than encouraging tourists to experience and learn the culture of the people living in the area; the culture that reflects the uniqueness of the people in the south. This study, therefore, aims to find creative tourism activities in SLB in order to increase the value of tourism resources, create tourism activities that are aligned with the resources available in the community and increase the number of tourists in the area. Data for this study were collected using a secondary source of data collection method. It was done through a literature review of related documents, texts, magazines, and research which focus on Songkhla Lake Basin as a guideline for designing tourism activities. The field survey was done through twelve community-based tourism sites in SLB to find creative tourism activities. Data on each activity were collected in detail by interviewing the tourism community leaders and the local people. Content analysis was used to describe the individual open-ended questions by focusing on the important issues and the information obtained was presented as a narrative. Keywords: Songkhla Lake Basin, Creative Tourism, Local Wisdom



2006 ◽  
Vol 33 (1) ◽  
pp. 25-52 ◽  
Author(s):  
William D. Samson ◽  
Cheryl L. Allen ◽  
Richard K. Fleischman ◽  
Ida B. Robinson-Backmon

Accounting educators no doubt agree that diversity is an important and much neglected part of accounting education. They further recognize that it is difficult to incorporate this important topic into the accounting curriculum. This paper describes the efforts of various professors to expose business and accounting students to the evolution of diversity issues related to the accounting profession by using the book A White-Collar Profession [Hammond, 2002]. A White-Collar Profession: African-American CPAs Since 1921 is a seminal work which presents a history of the profession as it relates to African-American CPAs and documents the individual struggles of many of the first one hundred blacks to become certified. This paper describes efforts of faculty at four different colleges to utilize this book in their teaching of accounting. Instructors found that students not only developed an enhanced awareness about the history of the accounting profession, but that other educational objectives were advanced, such as improved communication and critical thinking skills, increased social awareness, and empathy for others. African-American students, in particular, embraced the people in the book as role models, while most every student saw the characters as heroic in a day when the accounting profession is badly in need of role models and heroes. This is encouraging given the profession's concern with diversity and the attention and resources directed at increasing the number of minorities entering the profession.



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