Assessment of Normal Knee Kinematics Using High-Speed Stereo-Radiography System

The measurement of dynamic joint kinematics in vivo is important in order to understand the effects of joint injuries and diseases as well as for evaluating the treatment effectiveness. Quantification of knee motion is essential for assessment of joint function for diagnosis of pathology, such as tracking and progression of osteoarthritis and evaluation of outcome following conservative or surgical treatment. Total knee arthroplasty (TKA) is an invasive treatment for arthritic pain and functional disability and it is used for deformed joint replacement with implants in order to restore joint alignment. It is important to describe knee kinematics in healthy individuals for comparison in diagnosis of pathology and understanding treatment to restore normal function. However measuring the in vivo dynamic biomechanics in 6 degrees of freedom with an accuracy that is acceptable has been shown to be technically challenging. Skin marker based methods, commonly used in human movement analysis, are still prone to large errors produced by soft tissue artifacts. Thus, great deal of research has been done to obtain more accurate data of the knee joint by using other measuring techniques like dual plane fluoroscopy. The goal of this thesis is to use high-speed stereo radiography (HSSR) system for measuring joint kinematics in healthy older adults performing common movements of daily living such as straight walking and during higher demand activities of pivoting and step descending in order to establish a useful baseline for the envelope of healthy knee motion for subsequent comparison with patients with TKA. Prior to data collection, validation and calibration techniques as well as dose estimations were mandatory for the successful accomplishment of this study

Effect of using different U/S probe Standoff materials in image geometry for interventional procedures : the example of prostate

PURPOSE: This study investigates the distortion of geometry of catheters and anatomy in acquired U/S images, caused by utilizing various stand-off materials for covering a transrectal bi-planar ultrasound probe in HDR and LDR prostate brachytherapy, biopsy and other interventional procedures. Furthermore, an evaluation of currently established water-bath based quality assurance (QA) procedures is presented. MATERIAL AND METHODS: Image acquisitions of an ultrasound QA setup were carried out at 5 MHz and 7 MHz. The U/S probe was covered by EA 4015 Silicone Standoff kit, or UA0059 Endocavity balloon filled either with water or one of the following: 40 ml of Endosgel(®), Instillagel(®), Ultraschall gel or Space OAR™ gel. The differences between images were recorded. Consequently, the dosimetric impact of the observed image distortion was investigated, using a tissue equivalent ultrasound prostate phantom - Model number 053 (CIRS Inc., Norfolk, VA, USA). RESULTS: By using the EA 4015 Silicone Standoff kit in normal water with sound speed of 1525 m/s, a 3 mm needle shift was observed. The expansion of objects appeared in radial direction. The shift deforms also the PTV (prostate in our case) and other organs at risk (OARs) in the same way leading to overestimation of volume and underestimation of the dose. On the other hand, Instillagel(®) and Space OAR™ "shrinks" objects in an ultrasound image for 0.65 mm and 0.40 mm, respectively. CONCLUSIONS: The use of EA 4015 Silicone Standoff kit for image acquisition, leads to erroneous contouring of PTV and OARs and reconstruction and placement of catheters, which results to incorrect dose calculation during prostate brachytherapy. Moreover, the reliability of QA procedures lies mostly in the right temperature of the water used for accurate simulation of real conditions of transrectal ultrasound imaging

Effects of Weight-Bearing on Tibiofemoral, Patellofemoral, and Patellar Tendon Kinematics in Older Adults

Quantification of natural knee kinematics is essential for the assessment of joint function in the diagnosis of pathologies. Combined measurements of tibiofemoral and patellofemoral joint kinematics are necessary because knee pathologies, such as progression of osteoarthritis and patellar instability, are a frequent concern in both articulations. Combined measurement of tibiofemoral and patellofemoral kinematics also enables calculation of important quantities, specifically patellar tendon angle, which partly determines the loading vector at the tibiofemoral joint and patellar tendon moment arm. The goals of this research were to measure the differences in tibiofemoral and patellofemoral kinematics, patellar tendon angle (PTA), and patellar tendon moment arm (PTMA) that occur during non-weight-bearing and weight-bearing activities in older adults. Methods: High-speed stereo radiography was used to measure the kinematics of the tibiofemoral and patellofemoral joints in subjects as they performed seated, non-weight-bearing knee extension and two weight-bearing activities: lunge and chair rise. PTA and PTMA were extracted from the subject’s patellofemoral and tibiofemoral kinematics. Kinematics and the root mean square difference (RMSD) between non-weight-bearing and weight-bearing activities were compared across subjects and activities. Results: Internal rotation increased with weight-bearing (mean RMSD from knee extension was 4.2 ± 2.4° for lunge and 3.6 ± 1.8° for chair rise), and anterior translation was also greater (mean RMSD from knee extension was 2.2 ± 1.2 mm for lunge and 2.3 ± 1.4 mm for chair rise). Patellar tilt and medial–lateral translation changed from non-weight-bearing to weight-bearing. Changes of the patellar tendon from non-weight-bearing to weight-bearing were significant only for PTMA. Conclusions: While weight-bearing elicited changes in knee kinematics, in most degrees of freedoms, these differences were exceeded by intersubject differences. These results provide comparative kinematics for the evaluation of knee pathology and treatment in older adults

Increased expression of phosphorrylated NBS1, a key molecule of the DNA damage response machinery, is an adverse prognostic factor in patients with de novo myelodysplastic syndromes

The expression of activated forms of key proteins of the DNA damage response machinery (pNBS1, pATM and γH2AX) was assessed by means of immunohistochemistry in bone marrow biopsies of 74 patients with de novo myelodysplastic syndromes (MDS) and compared with 15 cases of de novo acute myeloid leukemia (AML) and 20 with reactive bone marrow histology. Expression levels were significantly increased in both MDS and AML, compared to controls, being higher in high-risk than in low-risk MDS. Increased pNBS1 and γH2AX expression possessed a significant negative prognostic impact for overall survival in MDS patients, whereas pNBS1 was an independent marker of poor prognosis

Accurate Measurement of Healthy Joint Kinematics to Inform Diagnosis and Treatment

The description of human motion has a primary importance in different scientific areas such as medicine, sports, physical therapy. Kinematics specifically studies pure motion without reference to the causes of motion such as forces. Understanding the kinematics of human movement is of critical importance in medicine and biology. Motion measure­ment can be used in order to to evaluate functional performance of limbs under normal and abnormal conditions. Kinematic knowledge is also important for diagnosis and surgi­cal treatment of joint disease and the design of implants to rehabilitate function. Accurate joint kinematics is essential to protect articular functionality. An alteration may change the transmission of physiological loads, which could lead to degenerative arthrosis from compartmental overload. Thus, accurate measurement of healthy joint motion is needed to establish baseline kinematics and clinical parameters for assessment of natural joint func­tion, diagnosis of pathology, design of treatments, and evaluation of patient outcomes. The main aim of human motion analysis is the description of joint kinematics during daily living activity. Accurate quantification of hip/knee kinematics during activities of daily living and differing demand is essential since joint kinematics during functional tasks are influenced by external forces, joint position and the balance of active and passive contrib­utory forces across the joint of interest. Age range has also a significant impact on joint kinematics. Currently, it is unclear what aspects of the kinematic changes appearing with osteoarthritis are the result of the disease or part of natural aging. To our knowledge, no others have evaluated normal knee function for a cohort age matched to total knee arthroplasty (TKA) recipients and during activities that patients with TKA often report to be troublesome, such as descending a step and executing a turn during walking. Most descrip­tions of knee kinematics have been for younger adults and for a limited span of activities. Additionally, quantitative data of total knee arthroplasty kinematics is crucial for the eval­uation of the component failure and for providing guidelines for further advancement of the implant design. TKA is a regular surgical procedure to alleviate pain and restore knee function. Successful functional outcome following TKA is influenced by the geometry and design of the components as well as their interaction with the soft tissue surrounding this articulation. Thus, understanding the effect of design choices on in vivo kinematics and during different dynamic activities of daily living has become more essential since the connection between knee prosthesis kinematics and clinical performance is clearly in­creasing. Finally, to best of our knowledge no others have investigated and compared the 3D pelvic functional orientation across different populations that include healthy subjects, subjects that have undergone total hip arthroplasty (THA) and spinal-stabilized cohorts and during different static and dynamic activities. Furthermore, most studies have performed their measurements in static settings whereas the pelvic motion is dynamic. The functional orientation of the pelvis varies during different dynamic activities and the pelvis is not a fixed static bone when considering acetabular cup placement. This knowledge will help us to better understand the behavior of all spinopelvic parameters and aid decisions regarding acetabular component alignment. Differences in spinopelvic parameters across different patient populations and across static and dynamic activities are necessary to understand for accurate positioning of the acetabular component during total hip arthroplasty and reduce the likelihood of impingement events

Λέξεις με προθήματα: παράγωγες ή σύνθετες; Οι απόψεις των φοιτητών θεωρητικών σπουδών ως προς την ορολογία και την κατηγοριοποίηση

Σκοπός της παρούσας εργασίας είναι να εξετάσει ένα θέμα της μορφολογίας της Ν.Ε., την προθηματοποίηση και πώς αυτή αντιμετωπίζεται στο πλαίσιο του σχολείου. Πιο συγκεκριμένα, επιδιώκει να διερευνήσει εάν οι τελειόφοιτοι φοιτητές του Παιδαγωγικού τμήματος και συνεπώς οι μελλοντικοί εκπαιδευτικοί αντιλαμβάνονται τις λέξεις με προθήματα ως παράγωγες ή ως σύνθετες. Για τις ανάγκες της εργασίας γίνεται ενδελεχής μελέτη στα φαινόμενα της παραγωγής και της σύνθεσης. Διεξοδικά αναλύεται το φαινόμενο της προθηματοποίησης ενώ παράλληλα γίνεται και μια ιστορική επισκόπηση του φαινομένου στα Αρχαία Ελληνικά. Πρόκειται για ένα γλωσσικό φαινόμενο για το οποίο υπάρχουν ποικίλες απόψεις στον επιστημονικό χώρο, ενώ διαφορετικές είναι οι προσεγγίσεις που ακολουθούν τόσο οι επίσημες σχολικές γραμματικές όσο και τα σχολικά βιβλία. Για να πραγματοποιηθεί η έρευνα σχεδιάσαμε ένα ερωτηματολόγιο, το οποίο στόχευε να διερευνήσει την αντίληψη των φοιτητών για τις λέξεις με προθήματα. Το ερωτηματολόγιο είναι χωρισμένο σε τρία μέρη. Το πρώτο μέρος περιελάμβανε τα δημογραφικά στοιχεία των φοιτητών. Το δεύτερο μέρος περιελάμβανε ερωτήσεις πολλαπλής επιλογής, οι οποίες σχετίζονταν με τα επιμέρους ερευνητικά ερωτήματα και κυρίως με το πώς ορίζουν και αντιλαμβάνονται οι φοιτητές τις έννοιες παραγωγή και σύνθεση. Το τρίτο μέρος του ερωτηματολογίου περιελάμβανε μια πολυμερή κλίμακα κατάταξης. Εκεί οι φοιτητές έπρεπε να τοποθετήσουν καθεμία από τις 64 λέξεις που δόθηκαν, οι οποίες ήταν κατά κύριο λόγο λέξεις με προθήματα και επιλεγμένες με κριτήρια τη μορφολογική διαφάνεια και αδιαφάνεια καθώς και με το σημασιολογικό πεδίο. Σύμφωνα με τα ευρήματα, οι τελειόφοιτοι φοιτητές αντιλαμβάνονται τις λέξεις με προθήματα ως παράγωγες, γεγονός που δείχνει ότι έχει διαδραματίσει καταλυτικό ρόλο σε αυτούς η διδασκαλία των φαινομένων στο Πανεπιστήμιο. Ωστόσο, περαιτέρω διερεύνηση χρήζουν οι λέξεις με προθήματα, οι οποίες είχαν επιλεγεί με κριτήριο τη μορφολογική διαφάνεια και αδιαφάνεια, στις οποίες παρατηρήθηκε ότι οι επιλογές των φοιτητών ως προς την κατηγοριοποίησή τους ποίκιλαν περισσότερο.The purpose of this paper is to study the prefixation. In particular, it seeks to investigate whether the final- year graduated students of the Department of Education and consequently the future teachers perceive words with prefixes as derivatives or as compounds. For the needs of the work, a thorough study of phenomena of derivation and compounding is carried out. The phenomenon of prefixation is thoroughly analyzed by presenting the results of modern linguistic researches on the words with prefixes, while at the same time a historical overview of the phenomenon is made, indicating how these words were understood in Ancient Greek. This is a complex phenomenon as different views in the scientific field dominate on which linguistic items are considered prefixes. Furthermore, official grammar of the public school adapt different approaches for this phenomenon. For this reason, it is also analyzed how these phenomena are presented in the school books in order to explore whether formal educational policy is consistent with modern linguistic studies. To make the survey, a questionnaire was created, which aimed to explore students' perceptions of words with prefixes. The questionnaire was divided into three parts. The first part included student demographic data (gender, year of birth and year of study). The second part included multiple choice questions that were related to the individual research questions. The third part of the questionnaire included a multi-ranking scale, in which the students had to set each of the 64 words were given. According to the findings, the final- year graduated students perceive the words with prefixes as derivatives, which shows that the teaching of these phenomena at the University has been influenced them. However, further exploration and study require words with prefixes, which were selected on the basis of morphological transparency and opacity, where it was observed that the student's choice of categorization were differed more

Dependence of Muscle Moment Arms on In Vivo Three-Dimensional Kinematics of the Knee

Quantification of muscle moment arms is important for clinical evaluation of muscle pathology and treatment, and for estimating muscle and joint forces in musculoskeletal models. Moment arms estimated with musculoskeletal models often assume a default motion of the knee derived from measurements of passive cadaveric flexion. However, knee kinematics are unique to each person and activity. The objective of this study was to estimate moment arms of the knee muscles with in vivo subject- and activity-specific kinematics from seven healthy subjects performing seated knee extension and single-leg lunge to show changes between subjects and activities. 3D knee motion was measured with a high-speed stereo-radiography system. Moment arms of ten muscles were estimated in OpenSim by replacing the default knee motion with in vivo measurements. Estimated inter-subject moment arm variability was similar to previously reported in vitro measurements. RMS deviations up to 9.0 mm (35.2% of peak value) were observed between moment arms estimated with subject-specific knee extension and passive cadaveric motion. The degrees of freedom that most impacted inter-activity differences were superior/inferior and anterior/posterior translations. Musculoskeletal simulations used to estimate in vivo muscle forces and joint loads may provide significantly different results when subject- and activity-specific kinematics are implemented

Prevalence of Common Viral Skin Infections in Beach Volleyball Athletes

Viral skin infections often affect the sports community. The aim of this study was to assess the rates, location sites, and seasons of appearance of common viral cutaneous diseases in beach volleyball athletes in Greece. Five hundred and forty-nine beach volleyball athletes participated in this study. The average age was 28.4 years. The viral infections were herpes simplex (type 1), molluscum contagiosum and warts. The measured parameters included: gender, age, the season when athletes may be more susceptible to infections and the location of infection in the body. Practicing information such as the number of training years, number of weekly trainings, and average hours of daily training was also recorded. Incidence rates correlated in relation to age: (a) warts (p p p = 0.001); (b) years of training: warts (p p p = 0.004); (c) average hours of daily training: molluscum contagiosum (p = 0.006) and herpes simplex (p < 0.010). The skin is the largest organ, and the risk of infection should not be underestimated. Prevention, early detection, recognition, and treatment are related to health and athletic performance, but also to the risk of transmission

Safety of Tattoos and Permanent Make up (PMU) Colorants

The art of tattooing is a popular decorative approach for body decoration and has a corrective value for the face. The tattooing procedure is characterized by placing exogenous pigments into the dermis with a number of needles. The process of creating traditional and cosmetic tattoos is the same. Colorants are deposited in the dermis by piercing the skin with needles of specific shape and thickness, which are moistened with the colorant. Colorants (pigments or dyes) most of the time include impurities which may cause adverse reactions. It is commonly known that tattoo inks remain in the skin for lifetime. It is also a fact that the chemicals that are used in permanent makeup (PMU) colorants may stay in the body for a long time so there is a significant long-term risk for harmful ingredients being placed in the body. Tattoo and PMU colorants contain various substances and their main ingredients and decomposition components may cause health risks and unwanted side effects to skin

Comparison of Marker-Based and Stereo Radiography Knee Kinematics in Activities of Daily Living

Movement of the marker positions relative to the body segments obscures in vivo joint level motion. Alternatively, tracking bones from radiography images can provide precise motion of the bones at the knee but is impracticable for measurement of body segment motion. Consequently, researchers have combined marker-based knee flexion with kinematic splines to approximate the translations and rotations of the tibia relative to the femur. Yet, the accuracy of predicting six degree-of-freedom joint kinematics using kinematic splines has not been evaluated. The objectives of this study were to (1) compare knee kinematics measured with a marker-based motion capture system to kinematics acquired with high speed stereo radiography (HSSR) and describe the accuracy of marker-based motion to improve interpretation of results from these methods, and (2) use HSSR to define and evaluate a new set of knee joint kinematic splines based on the in vivo kinematics of a knee extension activity. Simultaneous measurements were recorded from eight healthy subjects using HSSR and marker-based motion capture. The marker positions were applied to three models of the lower extremity to calculate tibiofemoral kinematics and compared to kinematics acquired with HSSR. As demonstrated by normalized RMSE above 1.0, varus–valgus rotation (1.26), medial–lateral (1.26), anterior–posterior (2.03), and superior–inferior translations (4.39) were not accurately measured. Using kinematic splines improved predictions in varus–valgus (0.81) rotation, and medial–lateral (0.73), anterior–posterior (0.69), and superior–inferior (0.49) translations. Using splines to predict tibiofemoral kinematics as a function knee flexion can lead to improved accuracy over marker-based motion capture alone, however this technique was limited in reproducing subject-specific kinematics