scholarly journals Predicting Forefoot-Orthosis Interactions in Rheumatoid Arthritis Using Computational Modelling

2021 ◽  
Vol 9 ◽  
Author(s):  
Emily S. Kelly ◽  
Peter R. Worsley ◽  
Catherine J. Bowen ◽  
Lindsey S. Cherry ◽  
Bethany E. Keenan ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Soft Tissue ◽  
Shear Strain ◽  
Healthy Individual ◽  
Computational Modelling ◽  
Metatarsal Head ◽  
Foot Orthoses ◽  
Soft Tissue Thickness ◽  
Wide Range ◽  
Model Predictions

Foot orthoses are prescribed to reduce forefoot plantar pressures and pain in people with rheumatoid arthritis. Computational modelling can assess how the orthoses affect internal tissue stresses, but previous studies have focused on a single healthy individual. This study aimed to ascertain whether simplified forefoot models would produce differing biomechanical predictions at the orthotic interface between people with rheumatoid arthritis of varying severity, and in comparison to a healthy control. The forefoot models were developed from magnetic resonance data of 13 participants with rheumatoid arthritis and one healthy individual. Measurements of bony morphology and soft tissue thickness were taken to assess deformity. These were compared to model predictions (99th% shear strain and plantar pressure, max. pressure gradient, volume of soft tissue over 10% shear strain), alongside clinical data including body mass index and Leeds Foot Impact Scale–Impairment/Footwear score (LFIS-IF). The predicted pressure and shear strain for the healthy participant fell at the lower end of the rheumatoid models’ range. Medial first metatarsal head curvature moderately correlated to all model predicted outcomes (0.529 < r < 0.574, 0.040 < p < 0.063). BMI strongly correlated to all model predictions except pressure gradients (0.600 < r < 0.652, p < 0.05). There were no apparent relationships between model predictions and instances of bursae, erosion and synovial hypertrophy or LFIS-IF score. The forefoot models produced differing biomechanical predictions between a healthy individual and participants with rheumatoid arthritis, and between individuals with rheumatoid arthritis. Models capable of predicting subject specific biomechanical orthotic interactions could be used in the future to inform more personalised devices to protect skin and soft tissue health. While the model results did not clearly correlate with all clinical measures, there was a wide range in model predictions and morphological measures across the participants. Thus, the need for assessment of foot orthoses across a population, rather than for one individual, is clear.

The Effects of Body Position on Trochanteric Soft Tissue Thickness—Implications for Predictions of Impact Force and Hip Fracture Risk During Lateral Falls

2021 ◽  
pp. 1-9
Author(s):  
Benoit R. Lafleur ◽  
Alyssa M. Tondat ◽  
Steven P. Pretty ◽  
Marina Mourtzakis ◽  
Andrew C. Laing
Keyword(s):  
Hip Fracture ◽  
Soft Tissue ◽  
Fracture Risk ◽  
Impact Force ◽  
Community Dwelling ◽  
Tissue Thickness ◽  
Hip Fracture Risk ◽  
Soft Tissue Thickness ◽  
Model Predictions ◽  
Hip Rotation

Trochanteric soft tissue thickness (TSTT) is a protective factor against fall-related hip fractures. This study’s objectives were to determine: (1) the influence of body posture on TSTT and (2) the downstream effects of TSTT on biomechanical model predictions of fall-related impact force (Ffemur) and hip fracture factor of risk. Ultrasound was used to measure TSTT in 45 community-dwelling older adults in standing, supine, and side-lying positions with hip rotation angles of −25°, 0°, and 25°. Supine TSTT (mean [SD] = 5.57 [2.8] cm) was 29% and 69% greater than in standing and side-lying positions, respectively. The Ffemur based on supine TSTT (3380 [2017] N) was 19% lower than the standing position (4173 [1764] N) and 31% lower than the side-lying position (4908 [1524] N). As factor of risk was directly influenced by Ffemur, the relative effects on fracture risk were similar. While less pronounced (<10%), the effects of hip rotation angle were consistent across TSTT, Ffemur, and factor of risk. Based on the sensitivity of impact models to TSTT, these results highlight the need for a standardized TSTT measurement approach. In addition, the consistent influence of hip rotation on TSTT (and downstream model predictions) support its importance as a factor that may influence fall-related hip fracture risk.

The Effects of Clinical Factors and Retro-Odontoid Soft Tissue Thickness on Atlantoaxial Instability in Patients with Rheumatoid Arthritis

2017 ◽  
Vol 103 ◽  
pp. 364-370 ◽  
Author(s):  
Je Il Ryu ◽  
Myung Hoon Han ◽  
Jin Hwan Cheong ◽  
Jae Min Kim ◽  
Choong Hyun Kim ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Soft Tissue ◽  
Atlantoaxial Instability ◽  
Clinical Factors ◽  
Tissue Thickness ◽  
Soft Tissue Thickness

scholarly journals Sex differences in pedobarographic findings and relationship between radiograph and pedobarograph measurements in young healthy adults

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0002
Author(s):  
Kyoung Min Lee ◽  
Seung Yeol Lee ◽  
Moon Seok Park ◽  
Ki Hyuk Sung ◽  
Seungbum Koo ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Peak Pressure ◽  
Metatarsal Head ◽  
Healthy Adults ◽  
Tissue Thickness ◽  
First Metatarsal ◽  
Time Integral ◽  
Soft Tissue Thickness ◽  
Metatarsal Angle ◽  
Pressure Time

Category: Basic Sciences/Biologics Introduction/Purpose: Although pedobarographic measurement is increasingly used for clinical and research purposes, relatively few published studies have investigated normative data. This study examined pedobarographic findings in young healthy adults with regard to sex-related differences and correlations among measurement indices. Methods: Twenty young healthy adults (mean age 22.4 years, SD 1.2 years; 10 males and 10 females) were included. Weightbearing anteroposterior and lateral foot radiographs were taken, and dynamic pedobarographic data during treadmill walking and maximum ankle dorsiflexion were obtained. AP talo-first metatarsal angle, naviculocuboid overlap, lateral talo-first metatarsal angle, and plantar soft tissue thickness were measured on foot radiographs. Pedobarographic data including peak pressure and pressure-time integral were measured on five plantar segments: medial forefoot (MFF), lateral forefoot (LFF), medial midfoot (MMF), lateral midfoot (LMF), and heel. Results: Male and female subjects significantly differed in BMI (p<0.001), AP talo-first metatarsal angle (p=0.018), soft tissue thickness under the metatarsal head (p=0.04) and calcaneal tuberosity (p<0.001), maximum dorsiflexion during stance phase (p=0.041), peak pressure on the MFF (p=0.005) and LFF (p=0.004), and pressure-time integral on the MFF (p=0.018) and heel (p=0.001). Maximum dorsiflexion demonstrated significant negative correlations with pressure-time integral on the MFF (r=-0.595, p=0.007) and total pressure-time integral (r=-0.492, p=0.032). Pressure-time integral varus/valgus index was significantly correlated with pressure-time integral forefoot/heel index (r=0.472, p=0.036). Conclusion: Sex-related differences in pedobarographic examination were observed. Achilles stretching exercise was considered to reduce foot pressures, and subtalar joint was hypothesized to play an important role in pressure distribution.

Evaluation of 99mTc-Label led Vitamin K4 as an Agent for Testicular Imaging

1991 ◽  
Vol 30 (01) ◽  
pp. 35-39 ◽  
Author(s):  
H. S. Durak ◽  
M. Kitapgi ◽  
B. E. Caner ◽  
R. Senekowitsch ◽  
M. T. Ercan
Keyword(s):  
Soft Tissue ◽  
Room Temperature ◽  
Normal Subjects ◽  
Left Testis ◽  
Wide Range ◽  
Activity Ratios ◽  
The Right ◽  
Radioactivity Levels

Vitamin K4 was labelled with 99mTc with an efficiency higher than 97%. The compound was stable up to 24 h at room temperature, and its biodistribution in NMRI mice indicated its in vivo stability. Blood radioactivity levels were high over a wide range. 10% of the injected activity remained in blood after 24 h. Excretion was mostly via kidneys. Only the liver and kidneys concentrated appreciable amounts of radioactivity. Testis/soft tissue ratios were 1.4 and 1.57 at 6 and 24 h, respectively. Testis/blood ratios were lower than 1. In vitro studies with mouse blood indicated that 33.9 ±9.6% of the radioactivity was associated with RBCs; it was washed out almost completely with saline. Protein binding was 28.7 ±6.3% as determined by TCA precipitation. Blood clearance of 99mTc-l<4 in normal subjects showed a slow decrease of radioactivity, reaching a plateau after 16 h at 20% of the injected activity. In scintigraphic images in men the testes could be well visualized. The right/left testis ratio was 1.08 ±0.13. Testis/soft tissue and testis/blood activity ratios were highest at 3 h. These ratios were higher than those obtained with pertechnetate at 20 min post injection.99mTc-l<4 appears to be a promising radiopharmaceutical for the scintigraphic visualization of testes.

On the nominal transverse shear strain to characterize the severity of creasing

TAPPI Journal ◽  
2018 ◽  
Vol 17 (04) ◽  
pp. 231-240
Author(s):  
Douglas Coffin ◽  
Joel Panek
Keyword(s):  
Shear Strain ◽  
Transverse Shear ◽  
Elastic Limit ◽  
Experimental Results ◽  
Transverse Shear Strain ◽  
Maximum Strain ◽  
Machine Direction ◽  
Engineering Approach ◽  
Wide Range ◽  
Analytic Expression

A transverse shear strain was utilized to characterize the severity of creasing for a wide range of tooling configurations. An analytic expression of transverse shear strain, which accounts for tooling geometry, correlated well with relative crease strength and springback as determined from 90° fold tests. The experimental results show a minimum strain (elastic limit) that needs to be exceeded for the relative crease strength to be reduced. The theory predicts a maximum achievable transverse shear strain, which is further limited if the tooling clearance is negative. The elastic limit and maximum strain thus describe the range of interest for effective creasing. In this range, cross direction (CD)-creased samples were more sensitive to creasing than machine direction (MD)-creased samples, but the differences were reduced as the shear strain approached the maximum. The presented development provides the foundation for a quantitative engineering approach to creasing and folding operations.

Accuracy of robot-assisted versus optical frameless navigated stereoelectroencephalography electrode placement in children

2019 ◽  
Vol 23 (3) ◽  
pp. 297-302 ◽  
Author(s):  
Julia D. Sharma ◽  
Kiran K. Seunarine ◽  
Muhammad Zubair Tahir ◽  
Martin M. Tisdall
Keyword(s):  
Soft Tissue ◽  
Entry Point ◽  
Electrode Placement ◽  
Target Point ◽  
Localization Error ◽  
Bone Thickness ◽  
Tissue Thickness ◽  
Robot Assisted ◽  
Soft Tissue Thickness ◽  
Safety Margins

OBJECTIVEThe aim of this study was to compare the accuracy of optical frameless neuronavigation (ON) and robot-assisted (RA) stereoelectroencephalography (SEEG) electrode placement in children, and to identify factors that might increase the risk of misplacement.METHODSThe authors undertook a retrospective review of all children who underwent SEEG at their institution. Twenty children were identified who underwent stereotactic placement of a total of 218 electrodes. Six procedures were performed using ON and 14 were placed using a robotic assistant. Placement error was calculated at cortical entry and at the target by calculating the Euclidean distance between the electrode and the planned cortical entry and target points. The Mann-Whitney U-test was used to compare the results for ON and RA placement accuracy. For each electrode placed using robotic assistance, extracranial soft-tissue thickness, bone thickness, and intracranial length were measured. Entry angle of electrode to bone was calculated using stereotactic coordinates. A stepwise linear regression model was used to test for variables that significantly influenced placement error.RESULTSBetween 8 and 17 electrodes (median 10 electrodes) were placed per patient. Median target point localization error was 4.5 mm (interquartile range [IQR] 2.8–6.1 mm) for ON and 1.07 mm (IQR 0.71–1.59) for RA placement. Median entry point localization error was 5.5 mm (IQR 4.0–6.4) for ON and 0.71 mm (IQR 0.47–1.03) for RA placement. The difference in accuracy between Stealth-guided (ON) and RA placement was highly significant for both cortical entry point and target (p < 0.0001 for both). Increased soft-tissue thickness and intracranial length reduced accuracy at the target. Increased soft-tissue thickness, bone thickness, and younger age reduced accuracy at entry. There were no complications.CONCLUSIONSRA stereotactic electrode placement is highly accurate and is significantly more accurate than ON. Larger safety margins away from vascular structures should be used when placing deep electrodes in young children and for trajectories that pass through thicker soft tissues such as the temporal region.

Recycling and Reuse in the Roman Economy

2020 ◽  
Keyword(s):  
Building Materials ◽  
Computational Modelling ◽  
Late Antique ◽  
Roman Economy ◽  
Wide Range ◽  
The Status ◽  
Recent Developments ◽  
Methodological Approaches ◽  
First Time ◽  
Site Types

The recycling and reuse of materials and objects were extensive in the past, but have rarely been embedded into models of the economy; even more rarely has any attempt been made to assess the scale of these practices. Recent developments, including the use of large datasets, computational modelling, and high-resolution analytical chemistry, are increasingly offering the means to reconstruct recycling and reuse, and even to approach the thorny matter of quantification. Growing scholarly interest in the topic has also led to an increasing recognition of these practices from those employing more traditional methodological approaches, which are sometimes coupled with innovative archaeological theory. Thanks to these efforts, it has been possible for the first time in this volume to draw together archaeological case studies on the recycling and reuse of a wide range of materials, from papyri and textiles, to amphorae, metals and glass, building materials and statuary. Recycling and reuse occur at a range of site types, and often in contexts which cross-cut material categories, or move from one object category to another. The volume focuses principally on the Roman Imperial and late antique world, over a broad geographical span ranging from Britain to North Africa and the East Mediterranean. Last, but not least, the volume is unique in focusing upon these activities as a part of the status quo, and not just as a response to crisis.

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