Greater Compressive Forces Research Articles

A Novel Bone-Screw-Fastener Demonstrates Greater Maximum Compression Force Before Failure Compared With a Traditional Buttress Screw.

This study compared the maximal compression force before thread stripping of the novel bone-screw-fastener (BSF) with the traditional buttress screw (TBS) in synthetic osteoporotic and cadaveric bone models. The maximum compression force of the plate-bone interface before loss of screw purchase during screw tightening was measured between self-tapping 3.5-mm BSF and 3.5-mm TBS using calibrated load cells. Three synthetic biomechanical models were used: a synthetic osteoporotic diaphysis (model 1), a 3-layer biomechanical polyurethane foam with 50-10-50 pounds-per-cubic-foot layering (model 2), and a 3-layer polyurethane foam with 50-15-50 pounds-per-cubic-foot layering (model 3). For the cadaveric metaphyseal model, 3 sets of cadaveric tibial plafonds and 3 sets of cadaveric tibial plateaus were used. A plate with sensors between the bone and plate interface was used to measure compression force during screw tightening in the synthetic bone models, while an annular load cell that measured screw compression as it slid through a guide was used to measure compression in the cadaver models. Across all synthetic osteoporotic bone models, the BSF demonstrated greater maximal compression force before stripping compared with the TBS [model 1, 155.51 N (SD = 7.77 N) versus 138.78 N (SD = 12.74 N), P = 0.036; model 2, 218.14 N (SD = 14.15 N) versus 110.23 N (SD = 8.00 N), P < 0.001; model 3, 382.72 N (SD = 20.15) versus 341.09 N (SD = 15.57 N), P = 0.003]. The BSF had greater maximal compression force for the overall cadaver trials, the tibial plafond trials, and the tibial plateau trials [overall, 111.27 N vs. 97.54 N (SD 32.32 N), P = 0.002; plafond, 149.6 N versus 132.92 N (SD 31.32 N), P = 0.006; plateau, 81.33 N versus 69.89 N (SD 33.38 N), P = 0.03]. The novel bone-screw-fastener generated 11%-65% greater maximal compression force than the TBS in synthetic osteoporotic and cadaveric metaphyseal bone models. A greater compression force may increase construct stability, facilitate early weight-bearing, and reduce construct failure.

Grip Strength and Body Balance in Static and Dynamic Push Walkers Measurement Using Force Sensing Resistors and Kinect System

Most parents use push walkers to encourage toddlers in gross and fine motor stimulation to develop basic walking skills. Push walkers are a choice for parents other than baby walkers to help toddlers under one year learn to walk. The push walker options for toddlers include static (the shaft moves in place) and dynamic (moving mobile). This study aimed to compare the effect of push walkers between static and dynamic types on motor stimulation of toddlers using biomechanics by measuring hand grip strength and body balance. This research contributes to selecting a push walker for parents to support gross and fine motor development after agreeing on the consideration of the toddler expert panel for the toddler walking task simulation using a push walker involving nine toddlers according to body mass index. Simulation of toddler walking in two experimental sessions using static and dynamic push walkers in measuring hand grip strength using force-sensing resistors and body balance using the Kinect system with Vitruvius software. The grip strength value was tested by paired t-test to determine the significance of the grip strength value. Body balance values were tested by paired t-test to determine the significance of leg compression force and leg moment. Dynamic push walker has a greater value of grip strength than static, and p-value = 0.001 (&lt; 0.005), providing good motor stimulation to toddlers when pushing with more muscular grip strength, allowing the toddler's hand muscles to tighten up. Static push walkers have a greater compression force and foot moment than dynamic and p-value = 0.001 (&lt; 0.005), providing gross motoric stimulation to toddlers while walking in a balanced and stable manner, allowing the toddler's leg muscles to tighten up.

Use of blade tenderization to improve wooden breast meat texture2.

The effectiveness of blade tenderization (BT) in improving the texture of wooden breast (WB) meat was evaluated through compression and shear analyses. Butterfly fillets (n = 144) were collected during 3 sampling replications and scored as normal (NORM), moderate (WB MOD), or severe wooden breast (WB SEV). One side from each butterfly was blade tenderized and the other side served as an untreated control. Fillets were subjected to both compression and shear analyses in either the raw or cooked state. At 24h postmortem, drip loss, pH, and color traits were assessed on raw fillets. Muscle condition (M), treatment (T), measurement location (L), and their interaction effects were investigated. WB fillets were heavier (P < 0.0001) and possessed greater pH (P < 0.0001) than NORM fillets. L*a*b* values on the skin side were increased in WB fillets (P < 0.0001), as were drip and cook loss (P < 0.0001). Irrespective of degree of severity, WB meat was harder as evidenced by greater compression force (P < 0.0001) in both raw and cooked fillets. Shear force of raw meat progressively increased from NORM to WB SEV (P < 0.0001) but there were no shear differences between NORM and WB MOD after cooking. Blade tenderization decreased compression and shear values in both raw and cooked WB fillets compared to untreated controls (P < 0.01). The significance of location effect for compression force (P < 0.0001) suggested that WB texture was not uniform within the same fillet. In raw fillets, an M × T interaction (P < 0.0001) was found for both compression and shear values and indicated that blade-tenderized WB MOD and WB SEV still possessed harder texture than NORM meat. However, the cooked shear values of WB SEV fillets subjected to BT were similar to those of untreated NORM fillets. Therefore, BT improved, but did not fully resolve the issues of abnormal tactile and texture characteristics in WB meat in either the raw or cooked state.

A comparative study of the effect of drilling depth on generation of compressive force by headless compression screws using conical and cylindrical type of drill bit

BackgroundThis study was conducted to measure the effect of different drilling depths on compression forces generated by two commonly used headless compression screws using the two different types of drill bit, the Acutrak® mini (conical type drill bit) and the Synthes 3.0 HCS® (cylindrical type drill bit).MethodsA load cell was placed between two Sawbone blocks, which were 12 mm and 40 mm in thickness, respectively. After placing the guide pin into the center of the block, the drilling depth of the Acutrak® mini and Synthes HCS® screws ranged from 16 to 28 mm and 22 to 28 mm, respectively. The 24-mm screws were inserted and the compression force was measured immediately and at 30 min post-insertion.ResultsThe Acutrak® mini generated greater compression force compared to the Synthes 3.0 HCS® when drilled to a depth of less than 24 mm. The compression force of the Acutrak® mini showed a strong inverse correlation with the drilling depth. There was no significant inverse correlation observed between the compression force of the Synthes HCS® and the drilling depth.ConclusionsIf the screw length and the drill depth are the same, the Synthes 3.0 HCS® (cylindrical type drill bit) is safer and easier to use as it has no change in the compression force even when over-drilling because the compression force of the two screws is similar. As for the Acutrak® mini (conical type drill bit), while it is technically demanding due to varying compression force according to the drill depth, it can be used in certain cases because it can give stronger compression force through under-drilling.

Producing Fe–W–Co–Cr–C Alloy Cutting Tool Material Through Powder Metallurgy Route

High speed steel tools can withstand high impact forces as they are tough in nature. But they cannot retain their hardness at elevated temperature i.e. their hot hardness is low. Therefore permissible cutting speed is low and tools wear out easily. Use of lubricants is essential for HSS cutting tools. On the other hand cemented carbide tools can withstand greater compressive force, but due to lower toughness the tool can break easily. Moreover the cost of the tool is comparatively high. To achieve a better machining economy, Fe–W–Co–Cr–C alloys are being used nowadays. Their toughness is as good as HSS tools and hardness is very near to carbide tools. Even, at moderate cutting speeds they can be safely used in old machines having vibration. Moreover it is much cheaper than carbide tools. This paper highlights the Manufacturing Technology of the alloy and studies the comparative tribological properties of the alloy and tungsten mono carbide.

The Effects of Walking Speed on Tibiofemoral Loading Estimated Via Musculoskeletal Modeling

Net muscle moments (NMMs) have been used as proxy measures of joint loading, but musculoskeletal models can estimate contact forces within joints. The purpose of this study was to use a musculoskeletal model to estimate tibiofemoral forces and to examine the relationship between NMMs and tibiofemoral forces across walking speeds. We collected kinematic, kinetic, and electromyographic data as ten adult participants walked on a dual-belt force-measuring treadmill at 0.75, 1.25, and 1.50 m/s. We scaled a musculoskeletal model to each participant and used OpenSim to calculate the NMMs and muscle forces through inverse dynamics and weighted static optimization, respectively. We determined tibiofemoral forces from the vector sum of intersegmental and muscle forces crossing the knee. Estimated tibiofemoral forces increased with walking speed. Peak early-stance compressive tibiofemoral forces increased 52% as walking speed increased from 0.75 to 1.50 m/s, whereas peak knee extension NMMs increased by 168%. During late stance, peak compressive tibiofemoral forces increased by 18% as speed increased. Although compressive loads at the knee did not increase in direct proportion to NMMs, faster walking resulted in greater compressive forces during weight acceptance and increased compressive and anterior/posterior tibiofemoral loading rates in addition to a greater abduction NMM.

Evaluation of gait-related variables in lean and obese dogs at a trot

To assess differences in sagittal plane joint kinematics and ground reaction forces between lean and obese adult dogs of similar sizes at 2 trotting velocities. 16 adult dogs. Dogs with body condition score (BCS) of 8 or 9 (obese dogs; n = 8) and dogs with BCS of 4 or 5 (lean dogs; 8) on a 9-point scale were evaluated. Sagittal plane joint kinematic and ground reaction force data were obtained from dogs trotting at 1.8 and 2.5 m/s with a 3-D motion capture system, a force platform, and 12 infrared markers placed on bony landmarks. Mean stride lengths for forelimbs and hind limbs at both velocities were shorter in obese than in lean dogs. Stance phase range of motion (ROM) was greater in obese dogs than in lean dogs for shoulder (28.2° vs 20.6°), elbow (23.6° vs 16.4°), hip (27.2° vs 22.9°), and tarsal (38.9° vs 27.9°) joints at both velocities. Swing phase ROM was greater in obese dogs than in lean dogs for elbow (61.2° vs 53.7°) and hip (34.4° vs 29.8°) joints. Increased velocity was associated with increased stance ROM in elbow joints and increased stance and swing ROM in hip joints of obese dogs. Obese dogs exerted greater peak vertical and horizontal ground reaction forces than did lean dogs. Body mass and peak vertical ground reaction force were significantly correlated. Greater ROM detected during the stance phase and greater ground reaction forces in the gait of obese dogs, compared with lean dogs, may cause greater compressive forces within joints and could influence the development of osteoarthritis.

A Thermo-Mechanical Behavior Simulation of A NiTi Staple Used for the Correction of Idiopathic Scoliosis

In order to treat scoliosis, a thermo-mechanical behavior study of shape memory alloy bone staple has been proposed. A pre-stretched shape-memory-alloy bone staple, which has been heated above the transition temperature, provides greater compressive force upon insertion between two vertebrae and allows the control of idiopathic scoliosis development. Until now, the optimal design has not been reached due to the lack of appropriate design tools for shape memory alloy devices. In this paper, a shape memory alloy bone staple model is proposed by developing a user subroutine UMAT based on Boyd et al. unified thermodynamic shape memory alloy constitutive law using the finite element analysis software, ABAQUS. The numerical results for superelastic and shape memory effect under the tensile and three-point bending tests are presented. Simulations of the shape memory effects and force generation of the shape memory alloy staple are also shown.

A GLUTEN-FREE FLOUR MIX IS A SUCCESSFUL SUBSTITUTE WITH THE ADDITION OF XANTHAN GUM IN A YELLOW CAKE

TEXT: The purpose of this experiment was to determine if a commercial, gluten-free all-purpose flour (CGFF) mix could be substituted for all-purpose wheat flour in a traditional yellow cake recipe. Three variations of yellow cakes were tested. The control cake (CC) was made with all-purpose wheat flour. A gluten-free cake (GF) was made substituting CGFF for the wheat flour. A gluten-free cake with xanthan gum (GFX) was made using CGFF and 0.25% xanthan gum. Objective data regarding cake height, shear force and compression force, were measured using a using a universal texture analyzer (TA.XT2, Texture Technologies Corp., Scarsdale, NY/Stable Micro Systems, Haslemere, Surrey, UK). Batter viscosity was measured with a CSC Bostwick Consistometer. GF cakes were significantly shorter, required greater compression force, and less shear force than CC cakes. GFX cakes were similar to CC cakes in compression force, similar to GF cakes in shear force, and intermediate in height. The batters for the GF cakes were substantially less viscous than batter from GFX or CC cakes. Twenty-seven untrained sensory panelists evaluated cakes for sweetness and acceptability. The GF cakes were perceived to be less sweet and less acceptable than CC or GFX cakes. Acceptability of CC and GFX cakes was similar. The xanthan gum appeared to enhance the quality of the gluten-free cakes by increasing the batter viscosity, increasing the cake height, and resulted in a cake more similar to that of cakes made with wheat flour.

Knee osteoarthritis and high-heeled shoes

Little is known about the effects of walking in high heels on joints in the legs. Since osteoarthritis of the knee is twice as common in women as in men, we investigated torques (forces applied about the leg joints) of women who wore high-heeled shoes. We studied 20 healthy women who were comfortable wearing high-heeled shoes. The women walked with their own high-heeled shoes and barefoot. Data were plotted and qualitatively compared; major peak values for high-heeled and barefoot walking were statistically compared. Bonferroni adjustment was made for multiple comparisons. Measurement showed increased force across the patellofemoral joint and a greater compressive force on the medial compartment of the knee (average 23% greater forces) during walking in high heels than barefoot. The altered forces at the knee caused by walking in high heels may predispose to degenerative changes in the joint.

The Effect of Wax on Compaction of Microcrystalline Cellulose Beads Made by Extrusion and Spheronization

The effect of wax on the deformation behavior and compression characteristics of microcrystalline cellulose (Avicel® PH-101) and acetaminophen (APAP) beads is described. Beads of Avicel PH-101 and APAP formulations were prepared using extrusion and spheronization technology. A waxy material, glyceryl behenate, N.F. (Compritol ®), was added to the formulations in amounts ranging from 10% to 70% of total solid weight. Beads with a selected particle size range of 16-30 mesh were compressed with an instrumented single punch Manesty F press utilizing a 7/16-in. flat-faced tooling set. Compaction profiles were generated for the tablets to evaluate the effect of wax on the densification of beads containing wax. Beads made without wax (the control formulation) required greater compression forces to form cohesive tablets. As the amount of wax in the bead formulation was increased, the beads become more plastic and compressible. The Heckel equation which relates densification to compression pressure was used to evaluate the deformation mechanisms of the bead formulations. The analysis shows that as the level of wax in the bead formulation is increased, the yield pressure decreases, indicating that the beads densify by a plastic deformation mechanism.