Estimating body segment parameters from three-dimensional human body scans.

Body segment parameters are inputs for a range of applications. Participant-specific estimates of body segment parameters are desirable as this requires fewer prior assumptions and can reduce outcome measurement errors. Commonly used methods for estimating participant-specific body segment parameters are either expensive and out of reach (medical imaging), have many underlying assumptions (geometrical modelling) or are based on a specific subset of a population (regression models).

Adapting Fitness Age Calculations to Suit a Modern North American Female Population, Regardless of Age, Race, or Ability Level.

Fitness Age (FA) has been reported in Japan and South Korea as one way to assess an individual's overall health. To date, this method has not been used in North America. The objective of the current study was to assess the applicability of existing Fitness Age calculations for North American women.

Measurement of pubic symphysis width in different birthing positions using ultrasound.

Studies have shown that some vertical birthing positions, such as squatting and standing, may influence labour and childbirth. However, a rigorous biomechanical understanding of how different positions affect a woman's pelvis during labour is currently lacking. It was hypothesized that the position of pubic bones is affected in different positions, and thus the pubic symphysis width changes.

The effects of squatting while pregnant on pelvic dimensions: A computational simulation to understand childbirth.

Biomechanical complications of childbirth, such as obstructed labor, are a major cause of maternal and newborn morbidity and mortality. The impact of birthing position and mobility on pelvic alignment during labor has not been adequately explored. Our objective was to use a previously developed computational model of the female pelvis to determine the effects of maternal positioning and pregnancy on pelvic alignment.

Development and validation of a computational model for understanding the effects of an upright birthing position on the female pelvis.

Upright, natural birthing positions, such as squatting, are associated with several clinical benefits, yet recumbent positions are still most common during delivery in most health centres. The biomechanics of birth positioning are not yet fully understood; therefore, our objectives were to develop and validate a computational model that could determine pelvic kinematics under loading conditions resulting from an upright birthing position. A three-dimensional model of the pelvic region was created from MRI scans of a non-pregnant subject.

Determining loads acting on the pelvis in upright and recumbent birthing positions: A case study.

Background: The biomechanics of mothers' birthing positions and their impact on maternal and newborn health outcomes are poorly understood. Our objectives were to determine the loads applied to the female pelvis during dynamic movement that may occur during childbirth; findings are intended to inform clinical understanding and further research on birth positioning mechanics.

Methods: An optical motion capture system and force platforms were used to collect upright and supine movement data from two pregnant and three non-pregnant participants.

A new geometric-based model to accurately estimate arm and leg inertial estimates.

Segment estimates of mass, center of mass and moment of inertia are required input parameters to analyze the forces and moments acting across the joints. The objectives of this study were to propose a new geometric model for limb segments, to evaluate it against criterion values obtained from DXA, and to compare its performance to five other popular models. Twenty five female and 24 male college students participated in the study.

Wrist postures and forces in tree planters during three tree unloading conditions.

Unlabelled: The aims of this study were to investigate wrist postures and forces while operating the shovel during tree planting and to determine if different tree unloading techniques result in variations in wrist postures and forces. Experienced tree planters performed the planting task in a laboratory environment for three conditions: (1) symmetric tree unloading, and asymmetric unloading resulting in (2) right-loaded planting bags and (3) left-loaded planting bags. An optoelectric system and a shovel instrumented with strain gauges captured wrist posture and forces at the wrist, respectively.

[Medical translations and practical compilations: a necessary coincidence?].

Fourteenth- and fifteenth-century medicine is characterised by a trickle-down effect which led to an increasing dissemination of knowledge in the vernacular. In this context, translations and compilations appear to be two similar endeavours aiming to provide access to contents pertaining to the particulars of medical practice. Nowhere is this phenomenon seen more clearly than in vernacular manuscripts on surgery.

CD40 pathway activation reveals dual function for macrophages in human endometrial cancer cell survival and invasion.

Reproductive malignancies are a major cause of cancer death in women worldwide. CD40 is a TNF receptor family member, which upon activation may mediate tumor regression. However, despite the great potential of CD40 agonists, their use as a therapeutic option for reproductive cancers has never been investigated.

Trunk postural demands of occupational activities of some merchant pregnant women in Benin, West Africa.

Unlabelled: Strenuous physical work puts expectant mothers at risk of experiencing back pain during the gestational months. Pregnant women in Benin perform physically demanding occupational tasks that include the lifting and carriage of heavy loads on their heads for commercial activities. A large percentage of pregnant subjects (58%) reported having back pain episodes since the start of their pregnancy.

Head load carriage and pregnancy in West Africa.

Background: The postures of the trunk and of the head relative to the trunk adopted during the specific task of head load carriage were measured for a group of pregnant women and a control group of non-pregnant women because this activity was identified as a risk factor for back pain during pregnancy.

Methods: The postural data of the trunk and of the head relative to the trunk were collected using two inclinometer devices and an electrogoniometer, respectively.

Findings: During walking, the load on the head caused significantly larger upper trunk extension and smaller flexion of the head relative to the trunk.

Pro-inflammatory type-1 and anti-inflammatory type-2 macrophages differentially modulate cell survival and invasion of human bladder carcinoma T24 cells.

Findings from numerous studies suggest that inflammation is likely to have an important role in bladder carcinogenesis and cancer disease progression. While macrophages (Mϕs) constitute a major inflammatory component of the stroma of human bladder carcinoma, the regulatory role of such inflammatory leukocytes in tumor cell survival and invasion remains elusive. Human urothelial bladder cancer (UBC) T24 cells and monocyte-derived macrophages were used to study the relative contribution of pro-inflammatory type-1 (Mϕ-1) and anti-inflammatory type-2 (Mϕ-2) macrophages in the regulation of UBC cell behaviour.

Musculoskeletal symptoms in tree planters in Ontario, Canada.

Unlabelled: Tree planting is extremely physical, seasonal, repetitive work with high risk for musculoskeletal injuries.

Objectives: (1) To assess musculoskeletal symptoms in tree planters as they develop over the course of the planting season. (2) To investigate the effect of pre-season level of physical activity on development of musculoskeletal symptoms.

Influence of the volume and density functions within geometric models for estimating trunk inertial parameters.

The geometric method combines a volume and a density function to estimate body segment parameters and has the best opportunity for developing the most accurate models. In the trunk, there are many different tissues that greatly differ in density (e.g.

Evaluation of forearm support provided by the Workplace Board on perceived tension, comfort and productivity in pregnant and non-pregnant computer users.

The aim of the study was to evaluate the effect of forearm support provided by the Workplace Board on perceived tension, comfort and productivity among pregnant and non-pregnant female computer workers. Ten pregnant and 18 non-pregnant women participated in the study. Participants completed three sets of tension/discomfort questionnaires at two week intervals.

Fatigability of back extensor muscles and low back pain during pregnancy.

Background: Back pain is the most frequently reported musculo-skeletal problem during pregnancy. High muscle fatigability has been associated with back pain in the general population. During pregnancy, the gradual increase in loads may have a training effect, increasing strength and endurance of back muscles.

Back pain of working pregnant women: identification of associated occupational factors.

The objective of this study was to identify major occupational factors that were significantly correlated with back pain in pregnant women working in higher education, health care and service areas. A total of 73 working pregnant women were surveyed using questionnaires specifically designed for evaluating correlations between occupational factors and severity of back pain; 37 women were interviewed at both 20 and 34 weeks of pregnancy, 17 at 20 weeks only, and 19 were interviewed at 34 weeks only. "Rest breaks allowed" and "job autonomy" were negatively correlated with severity of back pain at 20 weeks of pregnancy.

A comparison between a new model and current models for estimating trunk segment inertial parameters.

Modeling of the body segments to estimate segment inertial parameters is required in the kinetic analysis of human motion. A new geometric model for the trunk has been developed that uses various cross-sectional shapes to estimate segment volume and adopts a non-uniform density function that is gender-specific. The goal of this study was to test the accuracy of the new model for estimating the trunk's inertial parameters by comparing it to the more current models used in biomechanical research.

Effect of a desk attachment board on posture and muscle activity in women during computer work.

Working at a computer is part of a large number of jobs and has been associated with upper extremity musculoskeletal disorders and back pain. The study evaluated the effects of a board attachment on upper extremity and back. The findings are mixed in that the board may have a positive effect in preventing back pain, but may be detrimental to upper extremities.

Estimating segment inertial parameters using fan-beam DXA.

Body segment inertial parameters are required as input parameters when the kinetics of human motion is to be analyzed. However, owing to interindividual differences in body composition, noninvasive inertial estimates are problematic. Dual-energy x-ray absorptiometry (DXA) is a relatively new imaging approach that can provide cost- and time-effective means for estimating these parameters with minimal exposure to radiation.

Trunk density profile estimates from dual X-ray absorptiometry.

Accurate body segment parameters are necessary to estimate joint loads when using biomechanical models. Geometric methods can provide individualized data for these models but the accuracy of the geometric methods depends on accurate segment density estimates. The trunk, which is important in many biomechanical models, has the largest variability in density along its length.

Evaluation of effects of selected factors on inter-vertebral fusion-a simulation study.

This study simulated the effects of inter-vertebral disc degeneration and bone density distribution on the structural stiffness and strength provided by inter-vertebral fusion. Based on the original and redistributed bone density distributions, the effects of selected factors, including contact area between device/graft and vertebral endplates, endplate conditions, and bone growth capacity were evaluated using a factorial design of experiment. The simulation results suggested that the degeneration of inter-vertebral disc significantly affected the bone density and density distribution in adjacent vertebrae.

Three-dimensional analysis of the movement of lumbar spinal nerve roots in nonsimulated and simulated adhesive conditions.

Study Design: Biomechanical analysis of the movement of the lumbar spinal nerve roots (NRs).

Objectives: The characteristics of the movement of lumbar spinal NRs corresponding to the change of posture were three-dimensionally analyzed in nonsimulated and simulated adhesion conditions using a porcine model.

Summary Of Background Data: There is a paucity of data on the movement of NRs.

Simulation of bone adaptive remodeling using a stochastic process as loading history.

In this simulation study for bone adaptive remodeling, loading conditions are described as stochastic processes to catch the unpredictable characteristics of daily physical activities, which are observed to be closely related with bone adaptive remodeling. This will not only eliminate the necessity of arbitrary choices for loading conditions, but also generate greater flexibility for simulations of bone adaptive remodeling. The sensitivity of simulation outcomes to the parameters in the simulation algorithm was examined by applying stochastic loading conditions on finite element models of simplified spine structures.