ABSTRACT
BACKGROUND: The coupling and coordination control of the multi-link rigid body of human body is the key to stable walking. It is reported that the use of cell phones greatly increases the chance of falling down stairs when walking; however, it lacks the analysis of the dynamic stability, motion coordination and joint mechanics of the lower limbs when walking down stairs with cell phone intervention. OBJECTIVE: To investigate the effects of cell phone on coupling control strategy of the multi-link rigid body in lower extremity during stair descent. METHODS: Twenty healthy university students were recruited and conducted the stair descent under no-interference (single task) and cell phone (phone task) randomly. Using the method of synchronous acquisition of 3D kinematics and dynamics, the kinetic and kinematic data were synchronously collected to acquire the parameters of stair descent under both conditions. RESULTS AND CONCLUSION: (1) The intervention of phone task significantly reduced the dynamic stability in anterior-posterior/media-lateral direction, the first knee extension moment peak, the first dorsiflexion moment peak, the second hip flexion moment peak in sagittal plane during stance phase, and significantly increased the mean and standard deviation of hip-knee/knee-ankle relative phase angles during swing phase. (2) It is concluded that when the gait of human body changes from time to time, the coupling control ability of multi-link rigid bodies decreased and the risk of falling increased. (3) The intervention of phone task reduces the supporting moment of lower limbs in the supporting phase, reduces the stability of adjacent joint coordination control in the swinging phase, reduces the dynamic stability in front, back and inside directions, and increases the risk of falling.
ABSTRACT
Abstract With the insertion of distributed generation in distribution networks, security analysis becomes crucial, in islanded operation or when the system is connected to the grid. Dynamic stability analyses are necessary in order to achieve minimum levels of security and reliability. Such analyses are obtained through the solution of the algebraic-differential set of equations that model the distribution grid and their generators, which requires numerical solution methods. Therefore, this paper presents a computational tool for transient stability and large disturbance frequency stability analysis, considering distribution systems with the insertion of biomass-fed distributed generation, which may, or may not, have speed regulation systems. The presented tool may be employed to assess assorted system indexes, such as the severity of disturbances, the quality of a given operating condition, in terms of voltage and frequency operating limits, and the response of both the system and the generators in face of the action of speed regulators.
Subject(s)
Biomass , Electric Wiring , Algorithms , Regulatory Frameworks for HealthABSTRACT
Fall down is related to stability of persons,especially in the aged.Poor stability usually results in fall down.Compared with the concept of static stability,dynamic stability theory emphasizes the velocity-position of center of mass(CoM)to predict feasible move-ments rather than CoM position only. Dynamic stability can help to estimate the risk of fall, and guide the exercise about fall prevention from improvements of adaption to regain balance.The training program still needs more studies.
ABSTRACT
A ruptura do ligamento cruzado cranial é a principal causa de claudicação do membro pélvico em cães. A causa da ruptura é multifatorial como processo degenerativo, inflamatório e traumático. Acomete principalmente cães de grande porte, não havendo predisposição sexual. O principal sinal clínico é a claudicação. Os testes de compressão tibial e de gaveta são realizados para o diagnóstico, associados à anamnese. As radiografias são importantes para avaliação do platô tibial e o diagnóstico de doença articular degenerativa. Muitas técnicas cirúrgicas podem ser utilizadas para o tratamento. Atualmente as osteotomias são as mais aceitas, devido a conformação anatômica do joelho canino. O objetivo desse trabalho é descrever as principais osteotomias para o tratamento da ruptura do ligamento cruzado cranial em cães, relacionando as indicações e complicações de cada técnica. Conclui-se que existem várias técnicas de osteotomias para o tratamento da ruptura do ligamento cruzado cranial, cada uma com suas indicações e complicações. Sendo de grande importância a medida do ângulo do platô tibial para a escolha da técnica a ser utilizada...
The cranial cruciate ligament is the main cause of lameness in the pelvic limb in dogs. Rupture causes are multifactorial, such as degenerative, inflammatory and traumatic processes. It mainly affects large dogs with no gender predisposition. The main clinical sign is lameness. Tibial compression and tray tests are performed for diagnosis, together with anamnesis. Radiographs are also important for assessing the tibial plateau and the diagnosis of degenerative joint disease. Many surgical techniques can be used for treatment. Osteotomies are currently the most accepted ones, due to the anatomical conformation of the canine knee. The aim of this paper is to describe the main osteotomy for treating cranial cruciate ligament rupture in dogs, stating the indications and complications of each technique. It can be concluded that there are several osteotomy techniques for the treatment of cranial cruciate ligament, each of them with their own indications and complications. It is, therefore, very important to measure the tibial plateau angle for the correct choice of techniques...
La ruptura del ligamento cruzado craneal es la principal causa de claudicación del miembro pélvico en perros. La causa de la ruptura es multifactorial como proceso degenerativo, inflamatorio y traumático. Afecta principalmente perros grandes, no ocurriendo predisposición sexual. La principal señal clínica es la claudicación. Las pruebas de compresión tibial y la bandeja tibial se llevan a cabo para el diagnóstico, asociados a la anamnesis. Las radiografías son importantes para evaluación de la meseta tibial y el diagnóstico de la enfermedad degenerativa de las articulaciones. Muchas técnicas quirúrgicas pueden ser utilizadas para el tratamiento. Actualmente las osteotomías son las más aceptadas, debido la conformación anatómica de la rodilla canina. El objetivo de esta investigación ha sido describir las principales osteotomías para el tratamiento de la rotura del ligamento cruzado craneal en perros, relacionando las indicaciones y complicaciones de cada técnica. Se concluye que hay varias técnicas de osteotomías para el tratamiento de la ruptura del ligamento cruzado craneal, cada uno con sus indicaciones y complicaciones. Es de gran importancia la medida del ángulo de la meseta tibial para la elección de la técnica a ser utilizada...
Subject(s)
Animals , Dogs , /analysis , Ligaments/abnormalities , Ligaments/surgery , Osteotomy/rehabilitation , Osteotomy , Osteotomy/veterinaryABSTRACT
OBJECTIVES: Load carrying tasks are recognized as one of the primary occupational factors leading to slip and fall injuries. Nevertheless, the mechanisms associated with load carrying and walking stability remain illusive. The objective of the current study was to apply local dynamic stability measure in walking while carrying a load, and to investigate the possible adaptive gait stability changes. METHODS: Current study involved 25 young adults in a biomechanics research laboratory. One tri-axial accelerometer was used to measure three-dimensional low back acceleration during continuous treadmill walking. Local dynamic stability was quantified by the maximum Lyapunov exponent (maxLE) from a nonlinear dynamics approach. RESULTS: Long term maxLE was found to be significant higher under load condition than no-load condition in all three reference axes, indicating the declined local dynamic stability associated with load carrying. CONCLUSION: Current study confirmed the sensitivity of local dynamic stability measure in load carrying situation. It was concluded that load carrying tasks were associated with declined local dynamic stability, which may result in increased risk of fall accident. This finding has implications in preventing fall accidents associated with occupational load carrying.
Subject(s)
Humans , Young Adult , Acceleration , Biomechanical Phenomena , Gait , Lifting , Nonlinear Dynamics , WalkingABSTRACT
OBJECTIVES: Slip and fall accidents in the workplace are one of the top causes of work related fatalities and injuries. Previous studies have indicated that fall risk was related to postural and dynamic stability. However, the usage of this theoretical relationship was limited by laboratory based measuring instruments. The current study proposed a new method for stability assessment by use of inertial measurement units (IMUs). METHODS: Accelerations at different body parts were recorded by the IMUs. Postural and local dynamic stability was assessed from these measures and compared with that computed from the traditional method. RESULTS: The results demonstrated: 1) significant differences between fall prone and healthy groups in IMU assessed dynamic stability; and 2) better power of discrimination with multi stability index assessed by IMUs. CONCLUSION: The findings can be utilized in the design of a portable screening or monitoring tool for fall risk assessment in various industrial settings.