Chenghua Jiang

Study on the Trend and Disease Burden of Injury Deaths in Chinese Population, 2004–2010

Injuries are a growing public health concern in China, accounting for more than 30% of all Person Years of Life Lost (PYLL) due to premature mortality. This study analyzes the trend and disease burden of injury deaths in Chinese population from 2004 to 2010, using data from the National Disease Surveillance Points (DSPs) system, as injury deaths are classified based on the International Classification of Disease-10th Revision (ICD-10). We observed that injury death accounted for nearly 10% of all deaths in China throughout the period 2004–2010, and the injury mortality rates were higher in males than those in females, and higher in rural areas than in urban areas. Traffic crashes (33.79–38.47% of all injury deaths) and suicides (16.20–22.01%) were the two leading causes of injury deaths. Alarmingly, suicide surpassed traffic crashes as the leading cause of injury mortality in rural females, yet adults aged 65 and older suffered the greatest number of fatal falls (20,701 deaths, 2004–2010). The burden of injury among men (72.11%) was about three times more than that of womens (28.89%). This study provides indispensible evidence that China Authority needs to improve the surveillance and deterrence of three major types of injuries: Traffic-related injury deaths should be targeted for injury prevention activities in all population, people aged 65+ should be encouraged to take individual fall precautions, and prevention of suicidal behavior in rural females should be another key priority for the government of China.

Estimation of earthquake casualties using high-resolution remote sensing: a case study of Dujiangyan city in the May 2008 Wenchuan earthquake

From a disaster relief perspective, an immediate and efficient rescue operation after an earthquake can greatly increase the number of survivors. An effective rescue operation depends on two key elements: localisation of the affected areas and estimation of the number of casualties in these areas. Many more studies have been conducted on the localisation of affected areas than on casualty estimation. Consequently, this study develops a model for rapidly estimating the number of casualties using satellite remote sensing (SRS). The model is based on the attributes of damaged buildings, as these buildings cause the greatest harm to inhabitants and they can be detected by SRS. The model uses the damage index (DI) of buildings computed by a numerical damage model derived from SRS images to assess the extent of damage. The DI is then combined with the building’s materials and structure index, which is calculated using information from the local geographic information system, to compute the joint casualty index (JCI). Finally, the number of casualties is estimated by the product of the JCI multiplied by the number of people inside the damaged buildings at the time of the earthquake. The model is then applied to three towns in Dujiangyan City, as these were the areas that most severely affected by the Wenchuan earthquake. Preliminary results showed that there was little difference between the actual and estimated number of casualties. It is recommended that more casualty data should be included in the model to improve the accuracy of estimation.

An in vitro and finite element study of load redistribution in the midfoot

A good knowledge of midfoot biomechanics is important in understanding the biomechanics of the entire foot, but it has never been investigated thoroughly in the literature. This study carried out in vitro experiments and finite element analysis to investigate the midfoot biomechanics. A foot-ankle finite element model simulating the mid-stance phase of the normal gait was developed and the model validated in in vitro experimental tests. Experiments used seven in vitro samples of fresh human cadavers. The simulation found that the first principal stress peaks of all midfoot bones occurred at the navicular bone and that the tensile force of the spring ligament was greater than that of any other ligament. The experiments showed that the longitudinal strain acting on the medial cuneiform bone was −26.2±10.8 μ-strain, and the navicular strain was −240.0±169.1 μ-strain along the longitudinal direction and 65.1±25.8 μ-strain along the transverse direction. The anatomical position and the spring ligament both result in higher shear stress in the navicular bone. The load from the ankle joint to five branches of the forefoot is redistributed among the cuneiforms and cuboid bones. Further studies on the mechanism of loading redistribution will be helpful in understanding the biomechanics of the entire foot.

Peak vertical ground reaction force during two-leg landing: a systematic review and mathematical modeling.

Objectives. (1) To systematically review peak vertical ground reaction force (PvGRF) during two-leg drop landing from specific drop height (DH), (2) to construct a mathematical model describing correlations between PvGRF and DH, and (3) to analyze the effects of some factors on the pooled PvGRF regardless of DH. Methods. A computerized bibliographical search was conducted to extract PvGRF data on a single foot when participants landed with both feet from various DHs. An innovative mathematical model was constructed to analyze effects of gender, landing type, shoes, ankle stabilizers, surface stiffness and sample frequency on PvGRF based on the pooled data. Results. Pooled PvGRF and DH data of 26 articles showed that the square root function fits their relationship well. An experimental validation was also done on the regression equation for the medicum frequency. The PvGRF was not significantly affected by surface stiffness, but was significantly higher in men than women, the platform than suspended landing, the barefoot than shod condition, and ankle stabilizer than control condition, and higher than lower frequencies. Conclusions. The PvGRF and root DH showed a linear relationship. The mathematical modeling method with systematic review is helpful to analyze the influence factors during landing movement without considering DH.

Effects of bone Young's modulus on finite element analysis in the lateral ankle biomechanics

Finite element analysis FEA is a powerful tool in biomechanics. The mechanical properties of biological tissue used in FEA modeling are mainly from experimental data, which vary greatly and are sometimes uncertain. The purpose of this study was to research how Youngs modulus affects the computations of a foot-ankle FEA model. A computer simulation and an in-vitro experiment were carried out to investigate the effects of incremental Youngs modulus of bone on the stress and strain outcomes in the computational simulation. A precise 3-dimensional finite element model was constructed based on an in-vitro specimen of human foot and ankle. Youngs moduli were assigned as four levels of 7.3, 14.6, 21.9 and 29.2 GPa respectively. The proximal tibia and fibula were completely limited to six degrees of freedom, and the ankle was loaded to inversion 10° and 20° through the calcaneus. Six cadaveric foot-ankle specimens were loaded as same as the finite element model, and strain was measured at two positions of the distal fibula. The bone stress was less affected by assignment of Youngs modulus. With increasing of Youngs modulus, the bone strain decreased linearly. Youngs modulus of 29.2 GPa was advisable to get the satisfactory surface strain results. In the future study, more ideal model should be constructed to represent the nonlinearity, anisotropy and inhomogeneity, as the same time to provide reasonable outputs of the interested parameters.

The biomechanical influence of anterior vertebral body osteophytes on the lumbar spine: A finite element study

BACKGROUND CONTEXT Anterior vertebral body osteophytes are common with degeneration but their biomechanical influence on the whole lumbar spine remains unclear. PURPOSE To investigate the biomechanical influence of anterior vertebral body osteophytes on the whole lumbar spine. STUDY DESIGN/SETTING This is a study using finite element analysis. OUTCOME MEASURES Intersegmental rotation, maximum Mises stress, and intradiscal pressure on the intervertebral discs of different lumbar levels were calculated. METHODS A finite element model of an intact lumbar spine was constructed and validated against in vitro studies. The modified models, which had different degrees of anterior vertebral body osteophyte formation (OF) in combination with disc space narrowing, were applied with physiological loadings. RESULTS The lumbar levels with various degrees of OF altered the kinematics of these levels, which also affected the whole lumbar spine. In flexion and lateral bending, the segment that was one level inferior to the vertebra with OF showed a trend towards increased range of motion. On the intervertebral discs that were one level inferior to the OF level, a trend towards increase in the maximum von Mises stress was found on the annulus. CONCLUSIONS Segments adjacent to levels with anterior vertebral body osteophytes showed increased intersegmental rotation and maximum stress. Further clinical observation should be performed to verify the results in vivo.

The Essential of Hierarchy of E-Continuing Medical Education in China

The level gap among different hospitals which exists in China is leading to a situation that doctors in different level hospital share uneven continuing medical education (CME) environment cause the diagnosis divide of doctors. The number of patients seen and guidance from experts had a strong correlation with improvement of the doctors’ clinical ability. The implementation of CME needs to consider the two factors. After a primary survey, this study made a systematic and detailed analysis about the current CME situation in different level hospitals. Hospitals are classified into 3 levels. CME patterns via information technique corresponding to different levels were proposed. With this hierarchy continuing medical education, it’s hoped that the diagnosis level of doctors in different level hospital should be similar so that each individual can acquire high quality medical service.

Effect of Dropping Height on the Forces of Lower Extremity Joints and Muscles during Landing: A Musculoskeletal Modeling

The objective of this study was to investigate the effect of dropping height on the forces of joints and muscles in lower extremities during landing. A total of 10 adult subjects were required to landing from three different heights (32 cm, 52 cm, and 72 cm), and the ground reaction force and kinematics of lower extremities were measured. Then, the experimental data were input into the AnyBody Modeling System, in which software the musculoskeletal system of each subject was modeled. The reverse dynamic analysis was done to calculate the joint and muscle forces for each landing trial, and the effect of dropping-landing on the results was evaluated. The computational simulation showed that, with increasing of dropping height, the vertical forces of all the hip, knee, and ankle joints, and the forces of rectus femoris, gluteus maximus, gluteus medius, vastii, biceps femoris and adductor magnus were all significantly increased. The increased dropping height also resulted in earlier activation of the iliopsoas, rectus femoris, gluteus medius, gluteus minimus, and soleus, but latter activation of the tibialis anterior. The quantitative joint and muscle forces can be used as loading conditions in finite element analysis to calculate stress and strain and energy absorption processes in various tissues of the lower limbs.