Static Weight Distribution Research Articles

The mode of action of IL-23 in experimental inflammatory arthritic pain and disease

ObjectivesWe have previously reported using gene-deficient mice that the interleukin (IL)-23p19 subunit is required for the development of innate immune-driven arthritic pain and disease. We aimed to explore here, using a number of in vivo approaches, how the IL-23p19 subunit can mechanistically control arthritic pain and disease in a T- and B- lymphocyte-independent manner.MethodsWe used the zymosan-induced arthritis (ZIA) model in wild-type and Il23p19−/− mice, by a radiation chimera approach, and by single cell RNAseq and qPCR analyses, to identify the IL23p19-expressing and IL-23-responding cell type(s) in the inflamed joints. This model was also utilized to investigate the efficacy of IL-23p19 subunit blockade with a neutralizing monoclonal antibody (mAb). A novel IL-23-driven arthritis model was established, allowing the identification of putative downstream mediators of IL-23 in the control of pain and disease. Pain and arthritis were assessed by relative static weight distribution and histology, respectively.ResultsWe present evidence that (i) IL-23p19+ non-bone marrow-derived macrophages are required for the development of ZIA pain and disease, (ii) prophylactic and therapeutic blockade of the IL-23p19 subunit ameliorate ZIA pain and disease and (iii) systemically administered IL-23 can induce arthritic pain and disease in a manner dependent on TNF, GM-CSF, CCL17 and cyclooxygenase activity, but independently of lymphocytes, CGRP, NGF and substance P.ConclusionsThe data presented should aid IL-23 targeting both in the choice of inflammatory disease to be treated and the design of clinical trials.

The GM-CSF/CCL17 pathway in obesity-associated osteoarthritic pain and disease in mice

We have previously identified a granulocyte macrophage-colony stimulating factor (GM-CSF)/C-C motif ligand 17 (CCL17) pathway in monocytes/macrophages, in which GM-CSF regulates the formation of CCL17, and it is important for an experimental osteoarthritis (OA) model. We explore here additional OA models, including in the presence of obesity, such as a requirement for this pathway. The roles of GM-CSF, CCL17, CCR4, and CCL22 in various experimental OA models, including those incorporating obesity (eight-week high-fat diet), were investigated using gene-deficient male mice. Pain-like behavior and arthritis were assessed by relative static weight distribution and histology, respectively. Cell populations (flow cytometry) and cytokine messenger RNA (mRNA) expression (qPCR) in knee infrapatellar fat pad were analyzed. Human OA sera were collected for circulating CCL17 levels (ELISA) and OA knee synovial tissue for gene expression (qPCR). We present evidence that: i) GM-CSF, CCL17, and CCR4, but not CCL22, are required for the development of pain-like behavior and optimal disease in three experimental OA models, as well as for exacerbated OA development due to obesity, ii) obesity alone leads to spontaneous knee joint damage in a GM-CSF- and CCL17-dependent manner, and iii) in knee OA patients, early indications are that BMI correlates with a lower Oxford Knee Score (r=-0.458and p=0.0096), with elevated circulating CCL17 levels (r=0.2108and p=0.0153) and with elevated GM-CSF and CCL17 gene expression in OA synovial tissue. The above findings indicate that GM-CSF, CCL17, and CCR4 are involved in obesity-associated OA development, broadening their potential as targets for possible treatments for OA.

Static Body Weight Distribution and Girth Measurements Over Time in Dogs After Acute Thoracolumbar Intervertebral Disc Extrusion.

Dogs with thoracolumbar intervertebral disc extrusion (TL-IVDE) can exhibit variable neurologic deficits after decompressive surgery. The objectives of this study were to quantify changes in static weight distribution (SWD) and limb and body circumference over time in dogs recovering from surgery for TL-IVDE. Dogs with acute TL-IVDE were prospectively evaluated at baseline (48–72 h post-operatively), 2, 4, 8, and 12 weeks post-operatively. Commercially-available digital scales were used to measure weight distributed to the pelvic limbs (PL%) and asymmetry between left and right pelvic limbs (LRA), each expressed as a percentage of total body weight. Trunk and thigh circumference measurements were performed using a spring-loaded tape measurement device. Measurements were performed in triplicate, compared to neurologically normal small breed control dogs and analyzed for changes over time. P <0.05 was significant. Twenty-one dogs were enrolled; 18 regained ambulation and 3 did not by study completion. PL% increased from 27.6% at baseline to 30.7% at 12 weeks but remained lower than in control dogs (37%) at all time points (p < 0.0001), even excluding dogs still non-ambulatory at 12 weeks (p < 0.025). LRA was similar to the control dogs, and did not have an association with surgical side. Caudal trunk girth decreased over time to 95% of baseline (p = 0.0002), but this was no longer significant after accounting for reductions in body weight (p = 0.30). Forward shifting of body weight persisted in dogs with TL-IVDE 12 weeks after surgery even among ambulatory dogs. SWD and circumference measurements could provide additional objective measures to monitor recovery.

Foot Typology, Dynamic and Static Weight Distribution, and Radiographic Changes After Subtalar Arthroereisis in Juvenile Symptomatic Flexible Flat Feet

Flexible flatfoot is among the most common skeletal disorders in childhood. This study describes the dynamic and static correction effects of subtalar arthroereisis in adolescents with flexible symptomatic flatfeet in comparison to normal subjects as well as to results before and after removal of metal. Eighteen adolescents with 25 symptomatic flexible flatfeet were treated surgically with a subtalar arthroereisis at a mean of 12.5 (10-16) years. At follow-up (mean 3.9 years, range 0.4-8), patients filled out the American Orthopaedic Foot and Ankle Society questionnaire, received radiographs and were examined using dynamic and static pedobarography as well as static hindfoot axis examination. Results were compared to healthy controls (n=13; 26 feet). Surgically treated feet (n=25) had better questionnaire results after surgery than before, but lower scores than healthy feet. Radiological parameters improved significantly after surgery. Removal of metal did not influence post-surgical results (follow-up 2.8 years). Surgically treated feet had larger contact areas than normal feet with predominance to the midfoot region. The relative maximum force, relative peak pressure and contact time were higher in the midfoot of treated feet compared to controls. When comparing pedobarography data of treated versus untreated feet of the same patients (subgroup n=11 feet), there were no differences. Subtalar arthroereisis was able to effectively treat symptomatic flexible flatfeet in this population. Results improved significantly evaluating a questionnaire, radiographs, dynamic and static weight distribution, but were still worse than results of healthy feet. There was no relapse after removal of metal.

Displacement of center of mass in dogs in response to foot sensory stimulation.

Evaluate center of mass (CoM) displacement values during four-limb and three-limb standing with limb suspension in dogs before and after applying sensory stimulation to a forelimb or hindlimb. Experimental study. Six clinically normal beagles. A four force-plate apparatus was built to assess static weight distribution. Dogs stood on the device with one limb in contact with each force plate. We created a plastic device to induce sensory stimulation so that lameness could not be detected visually when stimulating the paw. Experimenters confirmed the degree of lameness by walking before and after measurement. Body-weight shifts were induced via suspension of each limb and transient sensory stimulation to the right forelimb or left hindlimb. CoMs of five postures were compared, with and without transient sensory stimulation. The four-limb CoM was located cranial to the center of the X- and Y-axis coordinates (X: -0.82 ± 9.12, Y: 61.00 ± 5.82). During three-limb standing with suspension of either forelimb, CoM shifted backward toward the contralateral side compared to four-limb standing. During hindlimb suspension, CoM shifted to the contralateral side. With right forelimb sensory stimulation, there were large CoM changes for both four-limb and three-limb standing (X: -34.53 ± 9.09, Y: 52.21 ± 6.88). CoM changes were small with left hindlimb sensory stimulation (X: 6.47 ± 13.86, Y: 69.41 ± 5.55). CoMs during four-limb and three-limb standing were influenced by sensory stimulation of a forelimb and, to a lesser extent, of a hindlimb. Static evaluation of CoM may aid clinicians in the diagnosis and recovery of forelimb lameness.

Development of a simple method to measure static body weight distribution in neurologically and orthopedically normal mature small breed dogs

BackgroundObjective outcome measures capable of tracking different aspects of functional recovery in dogs with acute intervertebral disc herniation are needed to optimize physical rehabilitation protocols. Normal, pre-injury distribution of body weight in this population is unknown. The aims of this study were to quantify static weight distribution (SWD) using digital scales and to establish the feasibility of different scale methods in neurologically normal, mature, chondrodystrophic small breed dogs predisposed to intervertebral disc herniation.ResultsTwenty-five healthy, mature dogs were enrolled with a mean age of 4.6 years (SD 2.7) and a mean total body weight of 11.5 kg (SD 3.6). SWD for the thoracic and pelvic limbs and between individual limbs was acquired in triplicate and expressed as a percentage of total body weight using commercially available digital scales in four combinations: two bathroom, two kitchen (with thoracic and pelvic limbs combined), four bathroom and four kitchen (with limbs measured individually). SWD was also obtained using a pressure sensing walkway for comparison to scale data. Feasibility for each method was determined and coefficients of variation were used to calculate inter-trial variability. Mean SWD values were compared between methods using an ANOVA. The two bathroom scales method had the highest feasibility and lowest inter-trial variability and resulted in mean thoracic and pelvic limb SWD of 63 % (SD 3 %) and 37 % (SD 3 %), respectively. Thoracic limb mean SWD was higher for the PSW compared to any of the scale methods (p < 0.0001).ConclusionsSWD in a population of healthy chondrodystrophic dogs was simple to obtain using inexpensive and readily available digital scales. This study generated SWD data for subsequent comparison to dogs recovering from acute intervertebral disc herniation.

Longitudinal Vehicle Dynamics Modeling for AWD/4WD Vehicles to Study Torque Split between Front and Rear Axles

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;All-wheel Drive (AWD) is a mature technology and most automobile manufacturers offer this feature on their vehicles. Improved traction, enhanced vehicle stability, and better handling are some of the key characteristics of AWD vehicles which are achieved by distributing the appropriate level of torque to the front and rear axles. Accurately capturing the torque split between the two axles is essential for sizing of driveline components like gears, bearings, and shafts. Traditionally, the torque split is considered to be either 50-50%, or solely proportional to the static weight distribution between the two axles. Design decisions are made based on historical test data. In this paper a longitudinal vehicle dynamics model for AWD systems is proposed to understand the influence of various key factors such as dynamic weight transfer, compliance of driveline components, and changing tire radius on the torque split. Comparison with the test data is performed to understand the significance and limitations of the model. While more detailed models have been built and used for various purposes, to the authors’ knowledge, this is the first time a model with this level of fidelity is being used to evaluate driveline component durability.&lt;/div&gt;&lt;/div&gt;

English

During the night driving, the reaction time of a human driver go into a compromise due to inadequate peripheral vision or lack of color and depth perception. The conventional headlamps of any automotive vehicle are insufficient to provide an effective illumination in the road while the vehicle is negotiating a curve. The Adaptive Front Light System assists to improve the visibility of the road during the night time driving, which in turn improves safety by reducing the probability of accidents. The Adaptive Front Light System controls the aiming direction and pattern distribution of the low beam according to the amount of steering wheel angle, the vehicle speed and the direction of cornering. This feature is known as low beam “Swiveling”. Additionally, the Adaptive Front Light System is featured with a functionality called low beam “Leveling” which makes the head lamp capable of positioning the low beam exactly in to the intended position irrespective of the weight distribution between the front and rear side of the vehicle. Static weight distribution might happen if the vehicle is loaded with additional passengers or extra luggage in the boot space. Dynamic weight distribution might happen during the acceleration or braking, which introduces a pitching motion to the vehicle over the lateral horizontal axis. Furthermore, the Adaptive Front Light System features the High beam length adjustment in country roads according to the speed of the vehicle which in turn improves the visibility of the road while the vehicle is cruising with a high speed.

The effect of measurement method on static weight distribution to all legs in dogs using the Quadruped Biofeedback System

An application to measure static quadruped load distribution would be highly beneficial in the assessment of rehabilitation and lameness in many small animal patients. The scope of this study was to analyze the effects of confinement, location and local environment on the measurement of static quadruped load distribution as measured by the Quadruped Biofeedback System in normal dogs in order to better prescribe the use of this system. A prospective study of 20 healthy adult dogs was performed to evaluate effects on measurement on quadruped load distribution. Data collection in the form of mean load per extremity was recorded four times in five positions for a total of 20 measurements for each limb. A replicated cross-over design in which a mixed effect, repeated measures analysis of variance was used to test for main effects of treatment and end as well as their interaction. The effects of right vs. left within each end and for each end was analyzed for each treatment and significance of p < 0.01 was established. Measurements were taken from 20 healthy adult dogs with no obvious lameness at the time of data collection. Analysis by end suggests that measurements were affected in similar manners in comparable locations. Each method demonstrated consistency in measurement without any significant influence by day or session, suggesting that one standardized method be established for measurement. With standardization, the Quadruped Biofeedback System has potential use as a reliable instrument for the measurement of quadruped load distribution in dogs.

A skid steering model with track pad flexibility

The paper describes a model for predicting the skid-steering performance of tracked vehicles that allows for the flexibility of the track pads. It thus accounts for the reductions in friction moment that are observed as the radius of the turn is increased. The pad model computes a compound slip function and takes account of the shear stiffness of the pad and the limiting friction between the pad and the ground. Vehicle dimensions and the equations of motion are entered into a Microsoft Excel spreadsheet. The equations are solved using the Excel Solver routine. This avoids the need for specialised software or programming skills. It also gives good insight into the mechanics of steering and the factors affecting performance. Predicted sprocket torques for a Jaguar vehicle turning at different radii show good agreement with experimental measurements. The steering performance of an example six axle 24 tonne vehicle is computed and compared with that using the early Merritt/Steeds model that ignored track pad flexibility. The flexible pad model generally shows the vehicle to be slightly oversteer, whereas the Merritt/Steeds model predicts the vehicle to be understeer. At higher speeds the maximum cornering acceleration is likely to be limited by available power at the sprockets. Altering the static weight distribution of the vehicle shows that a forward weight distribution tends to cause a more oversteer response with reduced limiting lateral acceleration. With a rearward weight distribution, the vehicle response tends towards neutral to slight understeer. This is in contrast to Ackerman steered wheeled vehicles with pneumatic tyres where moving the CG forward tends to a more understeer response. Using the concept of static margin as applied to wheeled vehicles, it is suggested that a uniform or slightly forward weight distribution would make tracked vehicles less sensitive to external disturbances (cambered roads for example).

Evaluation of a pressure walkway system for measurement of vertical limb forces in clinically normal dogs

To compare ground reaction forces (GRFs) measured by use of a pressure-sensitive walk-way (PSW) and a force plate (FP) and evaluate weekly variation in the GRFs and static vertical forces in dogs. 34 clinically normal dogs and 5 research dogs with lameness. GRF data were collected from 5 lame and 14 clinically normal dogs by use of an FP and a PSW. Peak vertical force (PVF), vertical impulse (VI), and velocity measurements (determined by use of photocells and PSW data) were compared between groups. Peak vertical force, VI, stride length, ground phase time (ie, contact time), and static body weight distribution data were collected on 2 occasions, 1 week apart, in 20 different clinically normal dogs by use of a PSW; week-to-week variation in values was evaluated. Measurements of velocity derived by use of the photocells were not different from those derived by use of the PSW. For any 1 limb, values derived by use of the PSW were significantly lower than values derived with the FP. For values obtained by use of either technique, there were no differences between left and right limbs except for values of PVF measured via PSW in forelimbs. Values of PVF, VI, contact time, stride length, and static weight distribution generated by the PSW did not vary from week to week. Values for GRFs varied between the FP and PSW. However, data derived by use of PSW were consistent and could be used to evaluate kinetic variables over time in the same dog.

Reliability of Measurements of Static Weight Distribution of Manual Wheelchairs

The purpose of this study was to evaluate the reliability of measurements of weight distribution among the wheels of wheelchairs using a commercial balance testing system. Reliable data may be useful in the wheelchair evaluation and adjustment process. Three male full-time manual wheelchair users aged 30, 26, and 27 years with cervical spinal cord injuries 7.5, 6.5, and 10 years in duration participated. Calibration weights, unoccupied wheelchairs, and occupied wheelchairs were repeatedly placed on the force transducers of the balance testing system to obtain measurements of weight distribution. The intraclass correlation coefficients of the measurements were .99 for calibration weights, .96 for unoccupied wheelchairs and .98 for wheelchairs occupied by the subjects. The described use of this instrumentation appears to generate reliable measurements of static weight distribution. With further testing, this system may provide useful information related to manual wheelchair prescription and adjustment.

4537267 Belt tensioning mechanism : Ronald Satzler assigned to Caterpillar Tractor Co

The paper describes a model for predicting the skid-steering performance of tracked vehicles that allows for the flexibility of the track pads. It thus accounts for the reductions in friction moment that are observed as the radius of the turn is increased. The pad model computes a compound slip function and takes account of the shear stiffness of the pad and the limiting friction between the pad and the ground. Vehicle dimensions and the equations of motion are entered into a Microsoft Excel spreadsheet. The equations are solved using the Excel Solver routine. This avoids the need for specialised software or programming skills. It also gives good insight into the mechanics of steering and the factors affecting performance. Predicted sprocket torques for a Jaguar vehicle turning at different radii show good agreement with experimental measurements. The steering performance of an example six axle 24 tonne vehicle is computed and compared with that using the early Merritt/Steeds model that ignored track pad flexibility. The flexible pad model generally shows the vehicle to be slightly oversteer, whereas the Merritt/Steeds model predicts the vehicle to be understeer. At higher speeds the maximum cornering acceleration is likely to be limited by available power at the sprockets. Altering the static weight distribution of the vehicle shows that a forward weight distribution tends to cause a more oversteer response with reduced limiting lateral acceleration. With a rearward weight distribution, the vehicle response tends towards neutral to slight understeer. This is in contrast to Ackerman steered wheeled vehicles with pneumatic tyres where moving the CG forward tends to a more understeer response. Using the concept of static margin as applied to wheeled vehicles, it is suggested that a uniform or slightly forward weight distribution would make tracked vehicles less sensitive to external disturbances (cambered roads for example).

Axle torque distribution in 4WD tractors

Performance of a four-wheel drive (4WD) tractor can be optimized by controlling the power distribution between the front and near axles. This paper proposes an automatically controlled hitch system to adjust the vertical force on each axle and thereby control the axle torques. Factors affecting the functional relationship between axle torque ratio and hitch position were examined experimentally using a 1 5.7 scale model 4WD tractor. The relationship between axle torque and hitch position was affected by the initial static weight distribution, the vertical and horizontal drawbar loads and traction or soil conditions. Traction efficiency was not affected by the axle torque ratio.

Preliminary study on static weight distribution under the human foot as a measure of lower extremity disability

Only a few methods have been reported in the recent literature for measuring the forces under human feet in normal and abnormal cases. The purpose of the present investigation was to study whether the static weight distribution under feet on the parafrontal plane can be used as a measure of lower extremity disability by using a system of load cells as transducers. Three postpolio cases, three lower extremity amputees and three Perthes disease victims constituted the test group and five normal healthy adult males with sedentary habits formed the control group in this preliminary study. Normalised weight distribution under the right and left foot of each test group subject has been compared with the mean and s.d. of the control group. The test group subjects showed different degrees of variation from the control group in the static-weight-distribution pattern according to their disability.