Search results for " engineering"

In vitro comparative study on the friction of stainless steel wires with and without Orthospeed (JAL 90458) on an inclined plane

2016

Background: During the treatment of orthodontics, in the mechanics of slide, there takes place friction, which they reduce the slide of the arch across bracket. Therefore, clinical there takes place an increase of the time of treatment. There are different the technologies that try to reduce this friction, as the self-ligating braces. The purpose of this study was to research the in vitro behavior of JAL 90458 as a buffering agent which reduces friction between brackets and stainless steel arch wires of different cross sections and sizes. Material and Methods: Three types of stainless steel wires with different cross sections and three types of ligatures were used with and without JAL 90458…

Effect of Training-Induced Changes in Achilles Tendon Stiffness on Muscle–Tendon Behavior During Landing

2018

During rapid deceleration of the body, tendons buffer part of the elongation of the muscle–tendon unit (MTU), enabling safe energy dissipation via eccentric muscle contraction. Yet, the influence of changes in tendon stiffness within the physiological range upon these lengthening contractions is unknown. This study aimed to examine the effect of training-induced stiffening of the Achilles tendon on triceps surae muscle–tendon behavior during a landing task. Twenty-one male subjects were assigned to either a 10-week resistance-training program consisting of single-leg isometric plantarflexion (n = 11) or to a non-training control group (n = 10). Before and after the training period, plantarf…

Novel Digital Technique to Quantify the Area and Volume of Cement Remaining and Enamel Removed after Fixed Multibracket Appliance Therapy Debonding: …

2020

The aim of this study was to construct a novel, repeatable, reproducible, and accurate measurement protocol for the area and volume of the remaining cement after removal of fixed multibracket appliances, the area and volume of remaining cement after cement removal, the area and volume of enamel removed after cement removal, and the volume of cement used to adhere fixed multibracket appliances. A total of 30 brackets were cemented and removed with over 30 extracted teeth embedded into three experimental models of epoxy resin. The models were scanned before and after bracket placement, bracket debonding, and polishing the remaining cement. The brackets were submitted to micro-computed tomogra…

The distribution of cartilage thickness in the knee-joints of old-aged individuals -- measurement by A-mode ultrasound.

1997

Abstract Objective. To provide data on the normal distribution of cartilage thickness in the knee joints of old-aged individuals. Design. The accuracy and reproducibility of cartilage thickness measurements were evaluated with A-mode ultrasound, and the cartilage thickness distribution was examined throughout both knee joints of nine individuals aged between 62 and 94 yr. Background. Data on the variation of cartilage thickness in the joint surfaces are relevant for the design of computer models of diathrodial joints and for surgical and arthroscopic procedures, particularly the calculation of cartilage material properties from indentation tests. Methods. A 12.5 MHz A-mode ultrasound transd…

Speed-Related Energy Flow and Joint Function Change During Human Walking.

2021

During human walking, mechanical energy transfers between segments via joints. Joint mechanics of the human body are coordinated with each other to adapt to speed change. The aim of this study is to analyze the functional behaviors of major joints during walking, and how joints and segments alter walking speed during different periods (collision, rebound, preload, and push-off) of stance phase. In this study, gait experiment was performed with three different self-selected speeds. Mechanical works of joints and segments were determined with collected data. Joint function indices were calculated based on net joint work. The results show that the primary functional behaviors of joints would n…

Effect of saddle height on skin temperature measured in different days of cycling

2016

Infrared thermography can be useful to explore the effects of exercise on neuromuscular function. During cycling, it could be used to investigate the effects of saddle height on thermoregulation. The aim of this study was to examine whether different cycling postures, elicited by different knee flexion angles, could influence skin temperature. Furthermore, we also determined whether the reproducibility of thermal measurements in response to cycling differed in the body regions affected or not affected by saddle height. Sixteen cyclists participated in three tests of 45 min of cycling at their individual 50 % peak power output. Each test was performed in a different knee flexion position on …

Molekulare Signalwege der aseptischen Endoprothesenlockerung (Molecular pathways in aseptic loosening of orthopaedic endoprosthesis)

2008

Operative joint replacement to treat disabling joint conditions secondary to degenerative and inflammatory arthritides has become one of the most efficacious and cost-effective procedures to relieve pain and restore joint function. However, prosthetic implants are not built to last forever and osteolysis and aseptic loosening has been associated with prosthetic arthroplasties since their introduction. The functional life of a synthetic joint is influenced by many factors including the material of the implant, operation procedures and the surgeon involved, as well as patient-related factors. Although promising developments have been achieved in this field, more than 10% of all implants still…

Course of physical functioning and pain in osteoarthritis of the knee or hip: a systematic review

2014

Evaluation of efficacy and biocompatibility of a new absorbable synthetic substitute as a dural onlay graft in a large animal model.

2016

Numerous dura substitutes are commercially available, but no absorbable synthetic dura repair product has been used for both onlay and suture applications.The safety and effectiveness of a new absorbable synthetic substitute composed of Poly-L-lactide microfibers as onlay dural graft were evaluated.Physical properties and performance of the microfibrous synthetic dural substitute implanted as an onlay or suturable grafts were compared with these commercial products, including CODMAN ETHISORB™ Dura Patch and DuraGen™ Dural Graft Matrix, in a canine duraplasty model. The cerebrospinal fluid (CSF) leakage, macroscopic and microscopic observation at 30 and 90 days after implantation were invest…

Patient-specific computational evaluation of stiffness distribution in ascending thoracic aortic aneurysm

2021

Quantifying local aortic stiffness properties in vivo is acknowledged as essential to assess the severity of an ascending thoracic aortic aneurysm (ATAA). Recently, the LESI (local extensional stiffness identification) methodology has been established to quantify non-invasively local stiffness properties of ATAAs using electrocardiographic-gated computed tomography (ECG-gated CT) scans. The aim of the current study was to determine the most sensitive markers of local ATAA stiffness estimation with the hypothesis that direct measures of local ATAA stiffness could better detect the high-risk patients. A cohort of 30 patients (12 BAV and 18 TAV) referred for aortic size evaluation by ECG-gated…