Introduction: The knee is a biomechanically complex joint supported by multiple anatomical structures, making it vulnerable to multiple injuries. Finite element analysis is a valuable tool for studying joint biomechanics, particularly in pre-operative planning and injury evaluation. However, most models are based on computed tomography, which limits soft tissue visualization. Thus, a magnetic resonance imaging-based finite element model of the knee, incorporating bones, ligaments, tendons, cartilage, and menisci, was developed to improve realism and clinical relevance in biomechanical simulations. Materials and methods: Magnetic resonance imaging data were obtained from a healthy adult male using a 1.5T scanner and processed using RETOMO and Rhinoceros software for 3D reconstruction and modeling. Meshes were cleaned, optimized, and anatomically validated. All major knee structures were modeled, including the femur, tibia, fibula, patella, cruciate and collateral ligaments, patellofemoral ligaments, quadriceps and patellar tendons, menisci, and articular cartilage. Results: The resulting model reconstructed both hard and soft tissues of the knee joint with high anatomical fidelity, based on direct MRI segmentation and literature-supported anatomical definitions. The use of magnetic resonance imaging enabled high-resolution identification of soft tissues, while advanced mesh refinement preserved anatomical detail with optimized file management. The inclusion of structures like the anterolateral ligament and patellofemoral ligaments expands the model’s clinical relevance in addressing a wider range of knee pathologies. Conclusion: This magnetic resonance imaging-based finite element analysis model provides a detailed and comprehensive, representation of the healthy human knee, including bones, cartilage, menisci, and tendons. While some ligament attachment points were derived from literature rather than MRI data, the model provides a foundation for future biomechanical studies, surgical planning and personalized treatment simulations.
Finite element analysis (FEA) is a fundamental tool that can be used in the orthopaedic world to simulate and analyze the behaviour of different surgical procedures. It is important to be aware that removing more than 20% of the meniscus could increase the shear stress in the cartilage and enlarge the risk of knee joint degeneration. In this fact, the maximal shear stress value in the medial cartilage increased up to 225% from 0.15 MPa to 0.5 MPa after medial meniscectomy. Also, meniscal root repair can improve meniscal biomechanics and potentially reduce the risk of osteoarthritis, even in cases of a loose repair. FEA has been used to better understand the biomechanical role of cruciate ligaments in the knee joint. ACLr with bone-patellar tendon-bone graft at 60 N of pretension and double-bundle PCLr were closer to that of a native knee in terms of biomechanics. The addition of a lateral extra-articular augmentation technique can reduce 50% of tibial translation and internal rotation, protecting the graft and minimizing the risk of re-rupture. Interestingly, anatomic and non-anatomic medial patellofemoral ligament reconstruction increased the pressure applied to the patellofemoral joint by increasing patellar contact pressure to 0.14 MPa at 30° of knee flexion using the semitendinosus as a graft. After all the advances in medical imaging technologies, future studies should take into consideration patient-specific data on both anatomy and mechanics, in order to better personalize the experimental model.
The aim of this study is to compare the diagnostic performance of magnetic resonance imaging (MRI) against computed tomography (CT) in various aspects of local staging in colon cancer patients. This study was a prospective single arm diagnostic accuracy study. All consecutive adult patients with confirmed colon cancer that met the current criteria for surgical resection were considered as eligible. Diagnostic performance assessment included T (T1/T2 vs T3/T4 and < T3ab vs > T3cd) and N (N positive) staging, serosa and retroperitoneal surgical margin (RSM) involvement and extramural vascular invasion (EMVI). Imaging was based on a 3 Tesla MRI system and the evaluation of all sequences (T1, T2 and diffusion-weighted imaging-DWI series) by two independent readers. CT scan was performed in a 128 row multidetector (MD) CT scanner (slice thickness: 1 mm) with intravenous contrast. Pathology report was considered as the gold standard for local staging. Sensitivity (SE), specificity (SP), and area under the curve (AUC) were calculated for both observers. MRI displayed a higher diagnostic performance over CT in terms of T1/T2 vs T3/T4 (SE: 100% vs 83.9%, SP: 96.6% vs 81%, AUC: 0.825 vs 0.983, p < 0.001), N positive (p < 0.001) and EMVI (p = 0.023) assessment. An excellent performance of MRI was noted in the T3ab vs T3cd (CT AUCReader1: 0.636, AUCReader2: 0.55 vs MRI AUCReader1: 0.829 AUCReader2 0.846, p = 0.01) and RSM invasion diagnosis. In contrast to these, MRI did not perform well in the identification of serosa invasion. MRI had a higher diagnostic yield than CT in several local staging parameters.
To identify factors influencing the diagnostic performance of the quantitative imaging biomarkers ADC and ADCratio in prostate cancer (PCa) detection. A systematic literature search was conducted in Embase, Medline and Web of Science, for studies evaluating ADC values and ADCratio for PCa diagnosis, using the same patient cohorts and using histopathological references as ground truth. Pooled sensitivities, specificities, summary ROC curves and AUCs were calculated from constructed contingency data tables. Diagnostic performance (AUC) was quantitatively pooled using a bivariate mixed effects model. For identifying influencing factors, subgroup analysis, publication bias and heterogeneity assessment were investigated. Thirteen studies, involving 1038 patients and 1441 lesions, were included. For ADC, the pooled sensitivity and specificity was 80
In recent years school bullying and other forms of aggressive behaviors in children and adolescents have become an issue of great concern among parents, psychologists, and educators. This study examined the relationship between school bullying and animal abuse in a community sample of school-age children. One hundred and seventy-four elementary school students from central Greece participated in the study and filled in self-report questionnaires which examined animal abuse, bullying – victimization, empathy, self-control, and peer interactions. Results showed that bullying behavior and peer victimization are associated with both direct abuse of animals and witnessing violence against animals. Multiple regression analysis indicated that witnessing animal abuse and being victimized by peers are positive predictors of bullying. Empathy, self-control, and peer interactions failed to predict school bullying. We discuss theoretical mechanisms linking bullying/victimization and animal abuse as well as directions for future research.
Many studies have assessed students’ motivation through surveys, but only a few studies systematically investigated through students’ own words the reasons and aims of their achievement striving. In the present study, we rely on the Goal Complex Perspective (Sommet and Elliot in J Educ Psychol 109(8):1141–1162, 2017. https://doi.org/10.1037/edu0000199 ; Vansteenkiste et al. in Educ Psychol 49(3):153–174, 2014. https://doi.org/10.1080/00461520.2014.928598 ) to uncover qualitative differences in achievement motivation. Content analysis of 1303 statements made by 597 Greek secondary students revealed (i) more autonomous motivation than controlled motivation statements, (ii) spontaneously generated statements of mastery-learning and outcome goals but rarely of performance-normative goals, (iii) mastery-learning goals being coupled with both autonomous and controlled motivation, providing ecological support for the conceptualization of mastery goal complexes. Logistic regression analyses verified our classification, as students’ statements were predicted by corresponding types of motivation assessed by close, Likert-type questions. These findings, which align with the Goal Complex Perspective, are discussed in terms of the operational definition of autonomous and controlled motivation and achievement goals.
BACKGROUND:The present study aimed to evaluate the self-regulatory properties of anger on the performance of individuals under various motivational dispositions using an experimental design. METHODS:The participants were 99 university students who participated in response to extra credit. The performance of the participants was evaluated using the Tower of Hanoi task. Their anger was measured using a facial expression recognition system and arousal was assessed using a heart-rate monitoring device. Two motivational dispositions were assessed: performance goals with normative evaluative standards and performance goals with a focus on outcomes. RESULTS:The results indicated that a nonlinear function explained the relationship between anger, arousal, and achievement under different goal conditions. Specifically, the Cusp Catastrophe Model showed that anger levels beyond a critical point were associated with the unpredictability of performance during the normative goal condition, suggesting that anger disturbed the relationship between arousal and achievement. Interestingly, a linear model was relevant for explaining the same relationships during the outcome goal condition. CONCLUSION:Thus, this study concluded that anger plays a more salient role when coupled with the pressures arising from employing interpersonal evaluative standards.
Facial nerve iatrogenic injuries are serious and can negatively affect the quality of life of the patients. Due to the properties of the nerve, the complications are devastating involving the aesthetic appearance and the function of the face. Moreover, the multiple branches of the nerve increase the risk of an iatrogenic injury making the detailed knowledge of the anatomical correlations around them critical. In this review, a meticulous analysis was performed including the surgical procedures posing the greater risk of an iatrogenic injury as well as the full description of all the reported anatomical landmarks involving the extracranial course of the facial nerve.
The main purpose of the study is to investigate the possible effect of school teachers’ collaborative networks on their individual innovativeness and the innovative school climate. In addition, 174 Greek primary school teachers’ views were explored about their collaboration networks (three collaboration types), their perceived individual innovativeness, the possible existence of innovative school climate, and the support they received in order to promote and/or produce new ideas and practices. Results showed that most of the participant school teachers belong to two categories of the five in the individual innovativeness scale, the early adopters and the early majority, although 20% belongs to innovators. Teachers’ collaboration network types affect innovative school climate and their individual innovativeness, but there were not found correlation between innovative school climate and perceived teachers’ innovativeness. However, collaborative networks within school have a higher effect on teachers’ innovativeness, and innovative school climate can be predicted by the network within school and among schools, as well as by the support that school teachers receive. Article visualizations:
Never in history has the fabric of African neurosurgery been challenged as it is today with the advent of the novel coronavirus identified in 2019 (COVID-19). Even the most robust and resilient neurosurgical educational systems in the continent have been brought to their knees with neurosurgical trainees and young neurosurgeons bearing the brunt. In the face of this new reality, and in order to limit the impact of the current COVID-19 pandemic, multiple programs have implemented physical distancing to reduce in-person interactions. In some cases, residents have been asked to stay home at least until they are instructed otherwise. This unfortunate event presents an innovative opportunity for neurosurgical education in Africa. Herein, we detail the framework of an online neurosurgical education initiative to advance the education of African residents and young neurosurgeons during and after the COVID-19 pandemic.
Research on students’ motivation has mainly focused on interpersonal differences rather than on the ongoing, intrapersonal dynamics that forge students’ everyday life. In this five-month longitudinal (diary) study, we recruited a sample of 179 high school students from Greece (35.8% males; Mage=16.27; SD=1.02) to investigate through multilevel analyses the ongoing dynamics of students’ motivation. We did so by examining the relation between autonomous functioning and aspects of study regulation (namely, study efforts and procrastination) and well-being (namely, subjective vitality and depressive feelings). After controlling for perceived competence, we found week-to-week autonomous functioning to relate positively to study efforts and subjective vitality and negatively to procrastination and depressive feelings. Interestingly, implicit theories of ability - the degree to which one believes that ability is fixed or amenable - were found to moderate the week-to-week relations of autonomous functioning to study efforts and homework procrastination. In particular, autonomous functioning co-varied positively to study efforts and negatively to homework procrastination only among students who believed that ability is malleable. Also, beliefs that ability is fixed predicted poorer grades, lower mean levels of study efforts, and higher homework procrastination. The results underscore the necessity of taking a more dynamic view when studying motivational phenomena and the importance of jointly considering the implicit theory framework and self-determination theory.
STUDY DESIGN:Human herniated discs were obtained from discectomy specimens for the immunohistochemical detection of O-GlcNAc and O-GlcNAcase (OGA)/O-GlcNAc transferase (OGT).PURPOSE:This study aimed to quantify the extent of O-GlcNAcylation and its associated enzymes (OGT/OGA) in human degenerated intervertebral discs.OVERVIEW OF LITERATURE:The O-GlcNAcylation of nuclear, cytoplasmic, and mitochondrial proteins as well as the effects of such post-translational modifications are currently the focus of extensive research. O-GlcNAcylation is believed to contribute to the etiology of chronic illnesses by acting as a nutrient and stress sensor in the cellular environment. Mature intervertebral disc cells are chondrocyte-like cells, and O-GlcNAc has been shown to promote chondrocyte apoptosis in vitro. We believe that O-GlcNAcylation is a key regulator of disc degeneration.METHODS:Fifty-six specimens were fixed for 24 hours in a 10% solution of neutral-buffered formaldehyde, dehydrated, and embedded in paraffin. Tissue slices (4-µm-thick) were used for hematoxylin-eosin staining and immunohistochemistry.RESULTS:We found that O-GlcNAcylation of cytoplasmic proteins was less than that of nuclear proteins in both single cells and cell clusters. Cytoplasmic O-GlcNAcylation occurs subsequent to nuclear O-GlcNAcylation and is directly proportional to disc degeneration. OGT and O-GlcNAc expression levels were identical in all specimens examined.CONCLUSIONS:O-GlcNAc and OGA/OGT expression is shown to correlate for the first time with intervertebral disc cell degeneration. Increasing disc degeneration is associated with increasing O-GlcNAcylation in both nuclear and cytoplasmic proteins in human disc cells.
Performance at school is affected not only by students' achievement goals but also by emotional exchanges among classmates and their teacher. In this study, we investigated relationships between students' achievement goals and emotion perception ability and class affect and performance. Participants were 949 Greek adolescent students in 49 classes and their Greek language and mathematics teachers. Results from multilevel analyses indicated that students' mastery-approach and performance-approach goals were positively related to positive affect whereas performance-avoidance goals were negatively related to positive affect. At class-level, relationships between achievement goals and affect were moderated by students' emotion perception ability. These findings highlight the importance of emotion abilities and their role in motivational processes for class-level outcomes.
The present study examined relationships between leaders' emotional intelligence (EI) and subordinates' emotion and work attitudes and between leaders' and subordinates' EI and work outcomes. School directors and educators completed measures of EI, affect at work, job satisfaction, and burnout. A series of multilevel analyses found that leaders' use of emotion was positively related to subordinates' work emotionality and attitudes, whereas leaders' emotion regulation and self-emotion appraisal were negatively related to subordinates' emotion and work attitudes. Leaders' and subordinates' own EI was positively related to their own work emotionality and job satisfaction. These findings support a social interactionist perspective on emotions at work and a multilevel understanding of the effects of leaders' emotions intrapersonally and interpersonally.
BACKGROUND:Spontaneous spondylodiscitis is an uncommon disease, which may result in serious complications with potentially high morbidity and mortality. We conducted a prospective case study over a 2-year period in order to analyze the clinical features, approaches to management, and outcome of spondylodiscitis. METHODS:Eight consecutive patients (four men, four women; age range 53-82 years) suffering from spondylodiscitis were identified during the study period. Parameters recorded included: demographics, past medical history, predisposing factors, presenting signs and symptoms, spinal level and extension of the infection, laboratory indices of inflammation, microbiological testing, radiological assessment, kind and duration of treatment, follow-up magnetic resonance imaging (MRI) studies, and outcome. RESULTS:Duration of symptoms varied from 14 to 90 days. All patients had back pain; fever>or=38 degrees C was present in 5/8 (62.5%) and neurological findings in 6/8 (75%). Diabetes mellitus was identified in six (75%). Most of the patients had elevated laboratory markers of inflammation. At the initial MRI, 12 anatomical levels were found. The microorganism was identified in 7/8 by blood or bone marrow cultures (50% Staphylococcus aureus). None of the patients underwent surgical intervention. Seven patients (87.5%) recovered to full activity; follow-up MRI study results were not always in parallel with the clinical improvement of patients. CONCLUSIONS:Spontaneous spondylodiscitis should be considered in every patient with back pain accompanied by fever and laboratory markers of inflammation. The major predisposing risk factor seems to be uncontrolled diabetes. MRI appears to be the method of choice for confirming diagnosis. Timely and accurate diagnosis along with prompt administration of antibiotics appears mandatory for a favorable outcome and avoidance of surgical intervention.
Confluent hepatic fibrosis (CHF) is usually a feature of advanced cirrhosis, while occurrence in early stage compensated cirrhosis is uncommon. We report the imaging findings of masslike CHF in a patient with previously unsuspected compensated alcoholic cirrhosis. The combination of partially wedge shape, minimal capsular retraction, and homogeneous delayed enhancement on multiphase contrast-enhanced spiral CT led to the characterization of the lesions and establishment of the diagnosis of cirrhosis.