SUMMARY: Due to the complexity of head shape, limited 1D or 2D head anthropometry fail to fully capture its shape characteristics. Currently, there is limited research on clustering analysis of head shape from a shape difference perspective, especially for the head shape of Chinese people. Head shape is influenced by factors such as race, sex, and age, making it imperative to create a head shape database for Chinese individuals. In this study, three-dimensional head data of 339 Chinese young adult were collected, and the head shapes were clustered into 7 clusters using an improved k-medoids algorithm. The differences between clusters and the average head shape were further analyzed. It can be foreseen that the head shape database for Chinese young adult constructed in this study has important reference value for the ergonomic design of head-related products and head morphology research, among other fields.

RESUMEN: Debido a la complejidad de la forma de la cabeza, la antropometría limitada de ésta, en 1D o 2D, no logra capturar completamente sus características de forma. Actualmente, existen estudios limitados sobre el análisis de agrupamiento de la forma de la cabeza, desde una perspectiva de diferencia de forma, especialmente en el caso de la población china. La forma de la cabeza está influenciada por factores como la raza, el sexo y la edad, por lo que resulta imperativo crear una base de datos sobre la forma de la cabeza de los individuos chinos. En este estudio, se recopilaron datos tridimensionales de la cabeza de 339 adultos jóvenes chinos, y las formas de la cabeza se agruparon en 7 grupos utilizando un algoritmo k-medoids mejorado. Las diferencias entre los grupos y la forma promedio de la cabeza se analizaron a profundidad. Se puede prever que la base de datos sobre la forma de la cabeza de adultos jóvenes chinos construida en este estudio, tiene un valor de referencia importante para el diseño ergonómico de productos relacionados con la morfología de la cabeza, entre otros campos.

Abstract In this paper, LS-dyna software was used to simulate the charging process of cylindrical shell when EFP has different angles, and some interesting phenomena and laws were found. Cylindrical elastic wave σr was generated when the cylindrical shell was impacted by EFP. The cylindrical elastic wave σr was correlated with the time required for the cylindrical shell charge to be successfully detonated. When the EFP warhead penetration Angle θ ranges from 0° to 10°, the σr increases linearly with (cosθ)-1/2. With the increase of θ, the tangential velocity vy had an obvious effect on the impact of EFP on the cylindrical shell, and the linear relationship between the elastic wave σr and (cosθ)-1/2 does not change. When the θ was greater than 45°, EFP could not successfully impact and detonate the cylindrical shell charge. The EFP velocity was measured by velocity measurement method with an error of 1.3%. The experimental results have strong similarity with the simulation results, indicating that the parameters of the numerical simulation model have good reliability.

SUMMARY OBJECTIVE: To investigate the associations of high-mobility group box 1 and its specific receptor, receptor for advanced glycation end products with acute lung injury in patients with acute aortic dissection. METHODS: A total of 96 acute aortic dissection patients were divided into acute aortic dissection with acute lung injury group (38 cases) and acute aortic dissection without acute lung injury group (58 cases), according to partial pressure of oxygen/fraction of inspired oxygen. In addition, 44 healthy individuals were selected for the control group. The blood samples were taken. The serum high-mobility group box 1 and receptor for advanced glycation end products levels were detected by enzyme-linked immunosorbent assay, and the partial pressure of oxygen/fraction of inspired oxygen was measured. RESULTS: 24 h after admission, the high-mobility group box 1 and receptor for advanced glycation end products levels in acute aortic dissection with acute lung injury and acute aortic dissection without acute lung injury groups were significantly higher than those in the control group, respectively (p<0.05), and each index in acute aortic dissection with acute lung injury group was significantly higher than that in acute aortic dissection without acute lung injury group (p<0.05). At each time point within 96 h after admission, compared with acute aortic dissection without acute lung injury group, in acute aortic dissection with acute lung injury group, the high-mobility group box 1 and receptor for advanced glycation end products levels were increased, respectively, and the partial pressure of oxygen/fraction of inspired oxygen was decreased. The correlation analysis showed that, in acute aortic dissection patients, the high-mobility group box 1 and receptor for advanced glycation end products levels were negatively correlated with partial pressure of oxygen/fraction of inspired oxygen, respectively (p<0.05). CONCLUSIONS: The serum high-mobility group box 1 and receptor for advanced glycation end products levels may be associated with the occurrence of acute lung injury in acute aortic dissection patients. Monitoring the high-mobility group box 1 and receptor for advanced glycation end products levels can evaluate the risk of acute aortic dissection with acute lung injury.

SUMMARY: Lumbar disc herniation is considered to be the main pathological factor for the common clinical disease of low back pain. Biomechanical factor is an important cause of lumbar disc herniation, so it is urgent to analyze the stress/strain behavior of intervertebral disc under different loading condition. Slow repetitive loading is considered to be an important factor of spine and disc injuries, and the effect of fatigue load on internal displacement in the intervertebral disc was investigated by applying the optimized digital image correlation technique in this study. The first finding was that fatigue load had a significant effect on the displacement distribution in the intervertebral disc under compression. Superficial AF exhibited the largest axial displacements before fatigue load, while it exhibited the smallest axial displacements after fatigue load. Inner AF exhibited slightly smaller radial displacements than outer AF before fatigue load, while it exhibited significantly greater radial displacements than outer AF displacements after fatigue load. The second finding was that fatigue load had a certain effect on the internal displacement distribution in the flexed intervertebral disc under compression. Middle AF exhibited the smallest axial displacements before fatigue load, while deep AF exhibited the smallest axial displacements after fatigue load. The radial displacement distribution did not change before and after fatigue load, as the radial displacement in outer AF was the smallest, while the radial displacement in inner AF was the largest. The third finding was that with the increase in fatigue time and amplitude, the Young's modulus of the intervertebral disc increased significantly. This study can provide the basis for clinical intervertebral disc disease prevention and treatment? and is important for mechanical function evaluation of artificial intervertebral disc as well.

RESUMEN: La hernia de disco lumbar se considera el principal factor patológico para la enfermedad clínica común del dolor lumbar. El factor biomecánico es una causa importante de hernia de disco lumbar, por lo que es urgente analizar el comportamiento de esfuerzo / tensión del disco intervertebral bajo diferentes condiciones de carga. La carga repetitiva lenta se considera un factor importante de lesiones de columna y disco, y en este estudio el efecto de la carga de fatiga sobre el desplazamiento interno en el disco intervertebral se investigó mediante la aplicación de la técnica de correlación de imagen digital optimizada. El primer hallazgo fue que la carga de fatiga tuvo un efecto significativo en la distribución del desplazamiento en el disco intervertebral bajo compresión. El AF superficial exhibió los desplazamientos axiales más grandes antes de la carga de fatiga, mientras que exhibió los desplazamientos axiales más pequeños después de la carga de fatiga. El AF interno exhibió desplazamientos radiales ligeramente más pequeños que el AF externo antes de la carga de fatiga, mientras que exhibió desplazamientos radiales significativamente mayores que los desplazamientos AF externos después de la carga de fatiga. El segundo hallazgo fue que la carga de fatiga tenía un cierto efecto sobre la distribución del desplazamiento interno en el disco intervertebral flexionado bajo compresión. El AF medio exhibió los desplazamientos axiales más pequeños antes de la carga de fatiga, mientras que el AF profundo exhibió los desplazamientos axiales más pequeños después de la carga de fatiga. La distribución del desplazamiento radial no cambió antes ni después de la carga de fatiga, ya que el desplazamiento radial en la FA externa fue el más pequeño, mientras que el desplazamiento radial en la FA interna fue el más grande. El tercer hallazgo fue que con el aumento del tiempo de fatiga y la amplitud, el módulo de Young del disco intervertebral aumentó significativamente. Este estudio puede proporcionar la base para la prevención y el tratamiento clínico de la enfermedad del disco intervertebral, y también es importante para la evaluación de la función mecánica del disco intervertebral artificial.

Brown sugar and sticky rice were frequently used as organic additives in Chinese mortars. This study applied enzymatic spectrophotometric methods to identify sucrose and starch contents in traditional Chinese lime- and earth-based mortars. The focus was to understand and evaluate the qualitative detection capacity of enzymatic method in mortars, by first applying the method on a series of lab-prepared mortar specimens with specific amounts of brown sugar and sticky rice addition, then on historic mortar samples suspected to contain brown sugar and sticky rice. The potential contribution and limitations of enzymatic method in analysis of sucrose and starch in mortars was compared with other common available analytical methods. The results suggested that for lab-prepared brown sugar mortar specimens, enzymatic method was more sensitive and exclusive than chemical method, and particularly had higher detection capacity in lime mortars. For simulated mortars with sticky rice addition, enzymatic method showed no distinct detection capacity differences among the studied inorganic binders and comparing with chemical methods was more sensitive in earth-based mortars. Enzymatic analysis on historic mortar samples was able to distinguish some false-positive results from the chemical and FTIR analysis, which was then corroborated by SEM.

Silver embedded LiFePO4/C were preparad by direct hydrothermal synthesis of Li2CO3 FeSO4 and H3PO4 in mixed solution of Glucose and Ag(NH3)2OH Samples were characterized by XRD, SEM and galvanostatic charge-discharge test. Results show that silver particles are located in the inner part of synthesized diamond-like and rectangular particles. The reversible capacities of prepared samples are 141.3 mAh g-1 and no capacity loss are detected after 800 cycles at 1C.

LiFeP0(4)/C and LiFeP0(4)/C+Ag samples were prepared by sol-gel method. Samples were characterized by XRD, SEM, EIS and electrochemical discharge and charge tests. Silver modification does not affect the olivine structure of LiFeP0(4) but enhances its electrochemical performance in terms of discharge capacity and rate capacity. Discharge capacities are improved from 130.8 mAhg-1 of LiFeP0(4)/Cto 149.8mAhg-1 of LiFeP0(4)/C+Ag cathodes. EIS measurements show that Silver modification slightly decreases the charge transfer resistance of LiFePOyC, and lithium ion diffusion coefficient is enhanced from 2.89 x 10-14 to 8.17 x 10-13m²s-1.