Biomedical subjects

Jiangyue Zhang

Publications and source records attributed to Jiangyue Zhang.

11 recordsLinked to original sources

PubMed2026

Paleogenomics and habitat modeling reveal temperate Eurasian origins of woolly rhinoceroses.

The woolly rhinoceros was a prominent Ice Age megafaunal species, and there is limited knowledge regarding its origin and responses to past glacial cycles. We sequenced 29 mitochondrial and 14 nuclear genomes from Pleistocene specimens across Eurasia and modeled the species' habitats over the past 500,000 years. Our results suggest that its maternal genetic diversity mainly evolved in temperate Eurasia around 460 thousand to 420 thousand years ago during a prolonged glacial-interglacial transition. We found that a ~170-thousand-year-old East Asian individual was ancestral to all later populations, indicating East Asia as one possible origin of Late Pleistocene ancestry. We also identified the Altai region as a major climatic refugium. These findings highlight the crucial role of temperate Eurasia in the evolution of woolly rhinoceroses and the diversification of cold-adapted megafauna.

Animals↗

PubMed2006

Experimental model for civilian ballistic brain injury biomechanics quantification.

Biomechanical quantification of projectile penetration using experimental head models can enhance the understanding of civilian ballistic brain injury and advance treatment. Two of the most commonly used handgun projectiles (25-cal, 275 m/s and 9 mm, 395 m/s) were discharged to spherical head models with gelatin and Sylgard simulants. Four ballistic pressure transducers recorded temporal pressure distributions at 308kHz, and temporal cavity dynamics were captured at 20,000 frames/second (fps) using high-speed digital video images. Pressures ranged from 644.6 to -92.8 kPa. Entry pressures in gelatin models were higher than exit pressures, whereas in Sylgard models entry pressures were lower or equivalent to exit pressures. Gelatin responded with brittle-type failure, while Sylgard demonstrated a ductile pattern through formation of micro-bubbles along projectile path. Temporary cavities in Sylgard models were 1.5-2x larger than gelatin models. Pressures in Sylgard models were more sensitive to projectile velocity and diameter increase, indicating Sylgard was more rate sensitive than gelatin. Based on failure patterns and brain tissue rate-sensitive characteristics, Sylgard was found to be an appropriate simulant. Compared with spherical projectile data, full-metal jacket (FMJ) projectiles produced different temporary cavity and pressures, demonstrating shape effects. Models using Sylgard gel and FMJ projectiles are appropriate to enhance understanding and mechanisms of ballistic brain injury.

Biomechanical Phenomena↗

PubMed2006

Moment-rotation responses of the human lumbosacral spinal column.

The objective of this study was to test the hypothesis that the human lumbosacral joint behaves differently from L1-L5 joints and provides primary moment-rotation responses under pure moment flexion and extension and left and right lateral bending on a level-by-level basis. In addition, range of motion (ROM) and stiffness data were extracted from the moment-rotation responses. Ten T12-S1 column specimens with ages ranging from 27 to 68 years (mean: 50.6+/-13.2) were tested at a load level of 4.0 N m. Nonlinear flexion and extension and left and right lateral bending moment-rotation responses at each spinal level are reported in the form of a logarithmic function. The mean ROM was the greatest at the L5-S1 level under flexion (7.37+/-3.69 degrees) and extension (4.62+/-2.56 degrees) and at the L3-L4 level under lateral bending (4.04+/-1.11 degrees). The mean ROM was the least at the L1-L2 level under flexion (2.42+/-0.90 degrees), L2-L3 level under extension (1.58+/-0.63 degrees), and L1-L2 level under lateral bending (2.50+/-0.75 degrees). The present study proved the hypothesis that L5-S1 motions are significantly greater than L1-L5 motions under flexion and extension loadings, but the hypothesis was found to be untrue under the lateral bending mode. These experimental data are useful in the improved validation of FE models, which will increase the confidence of stress analysis and other modeling applications.

Adult↗

PubMed2006

Lateral impact injuries with side airbag deployments--a descriptive study.

The present study was designed to provide descriptive data on side impact injuries in vehicles equipped with side airbags using the United States National Automotive Sampling System (NASS). The database was queried with the constraint that all vehicles must adhere to the Federal Motor Vehicle Safety Standards FMVSS 214, injured occupants be in the front outboard seats with no rollovers or ejections, and side impacts airbags be deployed in lateral crashes. Out of the 7812 crashes in the 1997-2004 weighted NASS files, AIS > or = 2 level injuries occurred to 5071 occupants. There were 3828 cases of torso-only airbags, 955 cases of torso-head bag combination, and 288 inflatable tubular structure/curtain systems. Side airbags were not attributed to be the cause of head or chest injury to any occupant at this level of severity. The predominance of torso-only airbags followed by torso-head airbag combination reflected vehicle model years and changing technology. Head and chest injuries were coupled for the vast majority of occupants with injuries to more than one body region. Comparing literature data for side impacts without side airbag deployments, the presence of a side airbag decreased AIS=2 head, chest, and extremity injuries when examining raw data incidence rates. Although this is the first study to adopt strict inclusion-exclusion criteria for side crashes with side airbag deployments, future studies are needed to assess side airbag efficacy using datasets such as matched-pair occupants in side impacts.

Abdominal Injuries↗

PubMed2006

Validation of a clinical finite element model of the human lumbosacral spine.

Very few finite element models on the lumbosacral spine have been reported because of its unique biomechanical characteristics. In addition, most of these lumbosacral spine models have been only validated with rotation at single moment values, ignoring the inherent nonlinear nature of the moment-rotation response of the spine. Because a majority of lumbar spine surgeries are performed between L4 and S1 levels, and the confidence in the stress analysis output depends on the model validation, the objective of the present study was to develop a unique finite element model of the lumbosacral junction. The clinically applicable model was validated throughout the entire nonlinear range. It was developed using computed tomography scans, subjected to flexion and extension, and left and right lateral bending loads, and quantitatively validated with cumulative variance analyses. Validation results for each loading mode and for each motion segment (L4-L5, L5-S1) and bisegment (L4-S1) are presented in the paper.

Adult↗

PubMed2006

Automating 3D meshing method for patient-specific modeling.

The purpose of this study was to develop an automating meshing method for patient-specific modeling. Three-dimensional geometries of two six-month-old infant heads were reconstructed from the CT data. Finite element meshes including cranial bone of skull, brain, and suture were generated. Both static and dynamic analyses were performed to verify the models. The study for blunt impact of infant head was performed by using these patient-specific models.

Acceleration↗

PubMed2006

Role of translational and rotational accelerations on brain strain in lateral head impact.

Translational and rotational accelerations from blunt head impact can induce excessive brain strain and cause traumatic brain injuries. However, it is not clear which acceleration plays a major role in the mechanism. The current study used the SIMon human finite element head model (FEHM) and delineated the contributions of these accelerations using post mortem human subject (PMHS) lateral head impact experimental data. Results indicated that rotational acceleration contributes more than 90% of total strain, and translational acceleration produces minimal strain. Therefore, the rotational component is a more important biomechanical metric in this study.

Acceleration↗

PubMed2006

Brain strains in vehicle impact tests.

The purpose of this research was to use vehicle impact test data and parametric finite element analysis to study the contribution of translational accelerations (TransAcc) and rotational accelerations (RotAcc) on strain-induced head injuries. Acceleration data were extracted from 33 non-contact vehicle crash tests conducted by the US Department of Transportation, National Highway Traffic Safety Administration. A human finite element head model was exercised using head accelerations from the nine accelerometer package placed inside the driver dummy in these tests. Three scenarios were parameterized: both TransAcc and RotAcc, only TransAcc, and only RotAcc to demonstrate the contribution of these accelerations on brain injury. Brain strains at multiple elements, cumulative strain damage, dilatation damage, and relative motion damage data were compared. Rotational accelerations contributed to more than 80% of the brain strain. Other injury metrics also supported this finding. These findings did not depend on the crash mode, peak amplitude of translational acceleration (29 to 120 g), peak amplitude of rotational acceleration (1.3 to 9.4 krad/s ( 2 ) ) or HIC (68-778). Rotational accelerations appeared to be the major cause of strain-induced brain injury.

Acceleration↗

PubMed2005

Temporal cavity and pressure distribution in a brain simulant following ballistic penetration.

To study ballistic brain injury biomechanics, two common civilian full metal jacket handgun projectiles (25-caliber and 9-mm) were discharged into a transparent brain simulant (Sylgard gel). Five pressure transducers were placed at the entry (two), exit (two) and center (one) of the simulant. High-speed digital video photography (20,000 frames/second) was used to capture the temporal cavity pulsation. Pressure histories and high-speed video images were synchronized with a common trigger. Pressure data were sampled at 308 kHz. The 25-caliber projectile had an entry velocity of 238 m/s and exit velocity of 170 m/s. The 9-mm projectile had an entry velocity of 379 m/s and exit velocity of 259 m/s. Kinetic energies lost during penetration were 45.2 J for the 25-caliber projectile and 283.7 J for the 9-mm. Size of temporary cavities and pressures were dependent on projectile size and velocity. The 9-mm projectile created temporary cavities 1.5 times larger in size and lasted 1.5 times longer than the 25-caliber projectile. The 9-mm projectile had pressures three times higher than the 25-caliber projectile. Pressure differences between the center location and surrounding regions were approximately 1.4 times higher and lasted about 1.6 times longer in the 9- mm projectile than the 25-caliber projectile. Collapsing of the temporary cavity drew the brain simulant toward the center of the temporary cavity and created negative pressures of approximately -0.5 atmospheric pressure in the surrounding region. Pressures reached approximately +2 atmospheric pressure when temporary cavities collapsed. These quantified data may assist in understanding injury biomechanics and management of penetration brain trauma.

Biomechanical Phenomena↗

PubMed2004

Force and acceleration corridors from lateral head impact.

This study was conducted to provide force and acceleration corridors at different velocities describing the dynamic biomechanics of the lateral region of the human head. Temporo-parietal impact tests were conducted using specimens from ten unembalmed post-mortem human subjects. The specimens were isolated at the occipital condyle level, and pre-test x-ray and computed tomography images were obtained. They were prepared with multiple triaxial accelerometers and subjected to increasing velocities (up to 7.7 m/s) using free-fall techniques by impacting onto a force plate from which forces were recorded. A 40-durometer padding (50-mm thickness) material covering the force plate served as the impacting boundary condition. Computed tomography images obtained following the final impact test were used to identify pathology. Four specimens sustained skull fractures. Peak force, displacement, acceleration, energy, and head injury criterion variables were used to describe the dynamic biomechanics. Force and acceleration responses obtained from this experimental study along with other data will be of value in validating finite element models. The study underscored the need to enhance the sample size to derive probability-based human tolerance to side impacts.

Abbreviated Injury Scale↗

PubMed2004

A new biomechanically-based criterion for lateral skull fracture.

This work develops a skull fracture criterion for lateral impact-induced head injury using postmortem human subject tests, anatomical test device measurements, statistical analyses, and finite element modeling. It is shown that skull fracture correlates with the tensile strain in the compact tables of the cranial bone as calculated by the finite element model and that the Skull Fracture Correlate (SFC), the average acceleration over the HIC time interval, is the best predictor of skull fracture. For 15% or less probability of skull fracture the lateral skull fracture criterion is SFC < 120 g, which is the same as the frontal criterion derived earlier. The biomechanical basis of SFC is established by its correlation with strain.

Biomechanical Phenomena↗