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Objective: Change of control strategy in osteoporotic people and their focus on the hip strategy, also the occurred postural changes, result in the displacement of center of pressure (COP). This study was carried out to compare the static stability parameters in healthy, osteopenic and osteoporotic women. Methods: Seventy-one volunteer postmenopausal women aged 48-65 years were divided into three Normal (n=15), Osteopenic (n=26) and Osteoporotic (n=30) groups according to their bone mineral density of lumbar spine. Static balance was evaluated using force plate, in two positions: double leg standing (DLS) and Romberg standing (Rom), with eyes open, for 20 s. Standard deviation of velocity and amplitude of COP displacement in A-P and M-L direction and path length were evaluated. Results: In DLS, SD of velocity and amplitude for A-P displacement, showed a significant increase in osteoporotic and osteopenic groups in comparison with normal women (P<0.05). In Rom, SD of amplitude for AP displacement, in osteoporotic group showed a significant increase compared with the normal group (P=0.03). Path length of COP displacement in DLS position in osteoporotic and osteopenic groups was significantly more than the normal group (P=0.05). There was a significant negative correlation between bone mineral density and SD velocity and amplitude in AP direction, and also path length in two static positions. Conclusion: Increase in SD velocity and SD amplitude of COP displacement in A-P direction, that increase with the decrease in bone mineral density, may be due to the change of control strategy mechanisms in osteopenic and osteoporotic women. Investigation of these changes will be necessary to design the therapeutic methods for prevention of falling and bone fracture in osteoporotic patients.

Introduction: Ankle sprain is one of the most prevalent traumatic injuries in joints, which can lead to instability, osteoarthritis and functional deficit in the ankle. The purpose of this study was to determine the acute and late effects of kinesio taping (KT) on the postural sway in patients with ankle sprain.Material and methods: Fifteen subjects with history of ankle sprain (7 men and 8 women) were participated in this study including two periods of taping and non-taping sessions. The measurements included: displacement the centre of pressure (COP), speed of COP displacement and the standard deviation (SD) of COP displacement in the anteroposterior and lateral directions, with and without perturbation. All parameters were measured twice with one day interval before taping, immediately and 24 hours after taping, and immediately after tape removal.Results: There were not any significant differences in the mean and SD of COP displacement, the speed of COP displacement and KT and No-KT situations.Conclusion: This study’s findings indicate that KT may not improve the balance performance in subjects with ankle sprain.

Introduction: Reliable balance measures are crucial for effective stroke rehabilitation. This study examines the between-day and within-day reliabilities of the center of pressure (CoP) measures in chronic stroke survivors in different standing positions under the influence of motor and cognitive dual-tasking. Methods: Sixteen people (49.31±15.5 years, 5 females) with chronic stroke were assessed in two sessions, 48 hours apart. Participants completed three balance control conditions: Single-task, motor dual-task, and cognitive dual-task. They performed three trials of open-eye quiet standing and semi-tandem standing. Three trials of closed-eye quiet standing were conducted in the single-task condition. A 2-way random model of the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and minimal detectable change (MDC) were calculated for CoP mean velocity, anterior-posterior (AP) and medial-lateral (ML) mean velocity, the standard deviation (SD) of AP and ML velocity, and sway area. Results: Within-day ICC values were higher than between-day values (ICC: 0.78-0.96). Mean velocity and Mean±SD of velocity in the AP direction showed the highest relative and absolute reliabilities in an open-eye quiet standing position (ICC: 0.82-0.92, SEM: 0.67-1.24). Dual-tasking could increase the reliability of the CoP measures, except for the sway area (ICC: 0.53-0.93 changed to 0.84-0.96). MDCs ranged from 1.03 to 7.77 mm/s for velocity-based variables. Conclusion: Assessing the postural control system during dual-task conditions provides more reliable CoP measures, especially in a semi-tandem standing position. These findings can provide clinicians with valuable insights into detecting specific balance problems that post-stroke individuals encounter.

Background and Aims Adolescent idiopathic scoliosis (AIS) is a multifactorial spinal deformity with high prevalence, affecting spinal alignment, postural control, and gait mechanics. This study aims to examine the effect of scoliosis curvature direction on center of pressure (COP) kinematics and free moment (FM) parameters during gait.Methods In this study, participants included 14 adolescents with AIS categorized into right scoliosis (n=7) and left scoliosis (n=7), and 16 healthy peers as controls. Data related to the COP and FM parameters were collected using two Kistler force plates during the stance phase of gait. Statistical analysis was done using MANOVA for discrete variables and statistical parametric mapping (SPM) for time-series data.Results The AIS group had significantly higher body height (P=0.021) and trunk length (P=0.052) than the control group. No significant differences were found in the COP and FM parameters for the right leg between the groups. However, the left scoliosis subgroup showed a significantly larger range of anteroposterior COP displacement in the left leg (convex side) compared to the control group (P=0.027), as well as a larger FM mean and impulse compared to the right scoliosis subgroup (P=0.019).Conclusion Adolescents with right and left scoliosis demonstrate different gait adaptations, particularly in COP and FM dynamics, highlighting the need for curvature direction-specific rehabilitation protocols to enhance gait stability and neuromuscular control in AIS. Future studies should analyze scoliosis directions separately to characterize their biomechanical profiles.

Karstic water resources are one of the most important sources of water for the world's population, which accounts for 25-20% of the world's population; these resources are subject to increasing pressure and require special management due to the nature of the point recharges. In this research, after mapping vulnerability and zoning protection on karstic aquifer of Tange-Konara Yasuj using COP method, proposed restrictions was presented. At first, the geological and topographic maps of the area to transfer to GIS software were digitized. In order to provide data, maps, and information about the situation of karstification, soil, and vegetation field surveys was conducted multiple times. Then, the operations and mathematical calculations to mapping of factors and sub-factors considered in COP method, was conducted in GIS media. The results show that karstic aquifer vulnerability rate changes 0. 6 to 4. 2 which showing high to very low vulnerability for the study area; So that, high, moderate, and low vulnerability classes are on Quaternary, Asmari, and Pabdeh-Gurpi-Razak formations, with 1. 6, 77. 1, and 21. 2 percent of the area, respectively. The importance of each of the factors in determining the sensitivity of the aquifer in the study area can be considered as P> C> O. Finally, three protection zone was considered including I for areas with high vulnerability, II for areas with medium vulnerability, and III for areas with low and very low vulnerability that was presented in the form of a protective map.

Cop Robber game is a two player game played on an undirected graph. In this game, the cops try to capture a robber moving on the vertices of the graph. The cop number of a graph is the least number of cops needed to guarantee that the robber will be caught. We study cop-edge critical graphs, i. e. graphs G such that for any edge e in E(G) either c(G-e) < c(G) or c(G-e) > c(G). In this article, we study the edge criticality of generalized Petersen graphs and Paley graphs.

Objective: Flat foot is common deformity in children that medial longitudinal arch is decreased, which if not treated in childhood may lead to pain and other problems in adulthood. Insoles and orthopedic shoes usually prescribed for treatment of flat foot in children, but the biomechanical impact of these devices is not yet clear. The purpose of this study is comparison of two conventional orthoses intervention in Iran, including medical shoe and functional foot orthosis on static balance by measurement of displacement of center of pressure and cop sway velocity in children with flexible flat foot.Materials and Methods: This Quasi experimental study were accomplished on 30 children with flat foot and 10 healthy children for achievement of normal data in healthy children. Children stood unilaterally on force plate of Neurocom and in order to measurement of balance, displacement of center of pressure and COP (Center of Pressure) sway velocity were recorded.Results: The results related to displacement of the center of pressure in a flat foot showed with insoles and conventional shoe the amount of displacement of center of pressure significantly were reduced (p<0.05). There was no significant difference between orthopedic shoe and functional foot orthosis, (p=0.12). Results of COP sway velocity showed in barefoot condition COP sway the most and in comparison with orthopedic shoe COP sway velocity were decreased with functional foot orthosis and regular shoe (significant level was 0.05).Conclusion: According to result of this study about static balance in flat foot children, there was no significant different among orthopedic shoe and functional foot orthosis. Due to the reduced displacement of center of pressure with functional foot orthosis and rejection of orthopedic shoe by children it seems that prescription of functional foot orthosis with regular shoe can be properly administered in flat foot children.

This investigation was concentrated to discover the possibility of utilizing corn cops residues in the production of particleboard. Two press temperatures of 170 and 180 o C, and four ratios of corn cop/poplar wood particles (100/0, 75/25, 50/50 and 25/75) in the corn layer of the boards and 100% poplar wood particles in the surface layer were used. A combination of 16 treatments were reached and three laboratory boards for each treatment were made. Physical and mechanical properties of the boards were measured and statistically analyzed. The grouping of the averages was based on duncan multiple range test. The results indicated that the influence of the press temperature on modulus of rupture and modulus of elasticity was statistically significant and boards produced applying 170 o C reached the higher values. As the corn cop/poplar particles ratio in the particle mixture in core layer increased, both modulus of rupture and internal bonding deteriorated and the highest value were measured at 50/50 ratio of the particle in the core layer. The boards produced applying higher press temperature exhibited higher rate of thickness swelling. Lower ratios of the corn cop/poplar particle in the mixture of particles in the core layer improved the properties of the boards and two ratios of 50/50/ and 25/75 produced lower thickness swelling. The results of this research revealed that even though boards produced using corn cop/poplar particles did not produce comparable properties to the boards based on poplar particles, but it can be concluded that if 50/50 ratio of corn cop/poplar particles, press temperature of 170 o C is used for board making, the mechanical properties of the produced boards will meet the requirement of DIN specifications.