Objective:To investigate biomechanical changes of mandible in the impact injure simulated by finite element method (FEM).Methods:Mimics and Comsol software were used to build a FEM of human craniofacial bone based on CT scan data of a normal adult.LS-DYNA and Hypermesh software were used to simulate the impact with different quality,velocity and angulation pro-duced injures of human mandible,the biomechanical parameters of the mandible in the impact injury process were analysed.Results:A FEMof human maxillofacial bone was established,and the dynamic process of different impact force produced damage was simula-ted.Mandibular chin,angle and condylar neck was the stress concentrated area in the process of mandible injury.There was higher stress peak at the site which was closer to the impact position,the stress peak arrival time was also earlier.When the impactor with the same quality,the bigger the velocity,the greater the stress peak.When the impactor with the same velocity,the bigger the quali-ty,the greater the stress peak.When the impactor with the same velocity and quality,there was greater stress peak under the impact to mandible from angulation of 0 degree.Stress transfered to the surrounding bone from the impact position radially and gradually re-duced.The bone area with small cross-section was prone to high stress and more serious damage.Conclusion:The quality,the ve-locity,the impact angle and the impact site are the factors affecting the severity of impact injury.

The fruit of Pandanus tectorius (PTF) has a long history of use as a folk medicine to treat hyperlipidemia in Hainan province, South China. Our previous studies have shown that the n-butanol extract of PTF is rich in caffeoylquinic acids and has an adequate therapeutic effect on dyslipidemic animals induced by high-fat diet. In this work, seven caffeoylquinic acids isolated from PTF were screened for the lipid-lowering activity in HepG2 hepatoma cells. Oil-Red O staining, microscopy and intracellular triglyceride (TG) and total cholesterol (TC) quantification showed that 3-O-caffeoylquinic acid (3-CQA), 3, 5-di-O-caffeoylquinic acid (3,5-CQA), and 3,4,5-tri-O-caffeoylquinic acid (3,4,5-CQA) significantly inhibited lipid accumulation induced by oleic acid and decreased intracellular levels of TC and TG in a dose-dependent manner. These three caffeoylquinic acids showed no significant cytotoxicity at concentrations of 1 -50 μmol x L(-1) as determined by MTT assay. Realtime quantitative PCR revealed that 3-CQA and 3, 5-CQA significantly increased the expression of lipid oxidation-related genes PPARα, CPT-1 and ACOX1 while 3-CQA, 3, 5-CQA and 3,4,5-CQA decreased the expression of lipogenic genes SREBP-1c, SREBP-2, HMGR, ACC, FAS. Overall, 3-CQA, 3, 5-CQA and 3, 4, 5-CQA may be the principal hypolipidemic components in PTF which can decrease intracellular lipid accumulation through up-regulating the expression of lipid oxidative genes and down-regulating the expression of lipogenic genes.
Carcinoma, Hepatocellular ; metabolism ; China ; Cholesterol ; metabolism ; Gene Expression Regulation ; Hep G2 Cells ; Humans ; Lipid Metabolism ; Liver Neoplasms ; metabolism ; Oleic Acid ; Pandanaceae ; chemistry ; Quinic Acid ; analogs & derivatives ; chemistry ; Sterol Regulatory Element Binding Protein 1 ; Triglycerides ; metabolism

By genetic transformation with Agrobacterum rhizogenes and artificial chromosome doubling techniques, we studied the induction of hairy roots and their polyploidization, and subsequent plant regeneration and nicotine determination to enhance the content of nicotine in Nicotiana tabacum. The results show that hairy roots could be induced from the basal surface of leaf explants of N. tabacum 8 days after inoculation with Agrobacterium rhizogenes ATCC15834. The percentage of the rooting leaf explants was 100% 15 days after inoculation. The hairy roots could grow rapidly and autonomously on solid or liquid phytohormones-free MS medium. The transformation was confirmed by PCR amplification of rol gene of Ri plasmid and paper electrophoresis of opines from N. tabacum hairy roots. The highest rate of polyploidy induction, more than 64.71%, was obtained after treatment of hairy roots with 0.1% colchicine for 36 h. The optimum medium for plant regeneration from polyploid hairy roots was MS+2.0 mg/L 6-BA +0.2 mg/L NAA. Compared with the control diploid plants, the hairy roots-regenerated plants had weak apical dominance, more axillary buds and more narrow leaves; whereas the polyploid hairy root-regenerated plants had thicker stems, shorter internodes and the colour, width and thickness of leaves were significantly higher than that of the control. Observation of the number of chromosomes in their root tip cells reveals that the obtained polyploid regenerated plants were tetraploidy, with 96 (4n = 96) chromosomes. Pot-grown experiments showed compared to the control, the flowering was delayed by 21 days in diploid hairy roots-regenerated plants and polyploid hairy root-regenerated plants. GC-MS detection shows that the content of nicotine in polyploid plants was about 6.90 and 4.57 times the control and the diploid hairy roots-regenerated plants, respectively.
Agrobacterium ; Plant Roots ; growth & development ; Plants, Genetically Modified ; growth & development ; Polyploidy ; Regeneration ; Tobacco ; genetics ; growth & development ; Transformation, Genetic

Objective To develop a 3D finite element model for the human craniomaxillofacial region in an attempt to offer basis to the research of simulation of craniomaxillofacial injury.Methods A healthy adult male was submitted to head CT scan, and the data was imported into the Mimics 15.0 software for threshold segmentation and 3D reconstruction according to the classifications of bone tissue, skin tissue and subcutaneous tissue.The reconstruction data was imported into 3D reverse software Geomagic Studio 2012, and the images were optimized and the 3D model was generated.The three parts of the model were fitted according to the actual proportion using the 3D control software Solidworks 14.0, and then the boundary conditions were derived.Hypermesh 12.0 finite element processing software was used to build the volume mesh, and the model was established.Each layer of the model was given to the material parameters, and the simulation conditions were provided to test the model.Results This model was completely composed of volume meshes, including 214,250 hexahedral meshes and 411,920 nodes.This model can clearly show the stress distribution, the trend of fracture line, the displacement of fracture block of soft and hard tissue during the simulation, and the results are consistent with clinical practice.Conclusion A three-dimentional finite element model with good performance is established, which can be used for biomechamics simulation analysis of multiple sites on the head or the whole structure, and has a certain significance in clinical and scientific research.

Objective To analyze the data on hearing of recruited students from a teenager aviation school according to both the standards of PLA and those of the US Armed Forces , to learn about their differences in hearing standards in medi-cal selection, and to raise suggestions on establishing hearing standards for medical selection of flying cadets from teenager aviation schools .Methods The data collected on the first hearing test about hearing of students from Hebei Teenager Aviation School were collected .The validity of the data was determined according to the medical selection standards both of PLA and of the US Armed Forces respectively .The cases of qualified or unqualified recruits at high frequency and middle -low frequency were counted respectively and analyzed statistically .Results The unqualified recruits determined by PLA′s standards tended to be unqualified too when determined by the US Armed Forces standards .During the screening of high frequency hearing and the general hearing condition , the proportion of unqualified cases determined by the US selection standards was higher than that determined by PLA′s selection standard .In the screening of middle-low frequency hearing , no statistically significant difference was found in the proportion of unqualified cases when the two different selection standards were used.Conclusion The hearing standard for medical selection of flying cadets at high frequency in the US Armed Forces is stricter than that in the PLA .Meanwhile, the hearing standard at middle-low frequency in the US Armed Forces is different from that in the PLA , though there are no statistically significant differences in the proportion of unqualified cases.The hearing standards of the US Armed Forces are recommended in recruiting flying cadets for teenager flying schools .

Objective:To investigate the value of the lateral arm free flap (LAFF)in the repair of oral and maxillofacial defects af-ter resection of malignant tumor.Methods:22 cases received LAFF from January 2012 to December 2012 were studied.The flap size,preparation time,vessel diameter,anastomosis time,survival situation,success rate and postoperative results were observed. Results:The flap ranged from 14 cm ×8 cm to 6 cm ×4 cm.All flaps survived well without vascular crisis.Repair results were satis-factory.Conclusion:LAFF,with constant anatomy and simple preparation,can be applied in the repair of oral and maxillofacial de-fects after tumor resection.

Objective To measure the dimensional error of three dimensional printing maxilla models for the clinical application to oral and maxillofacial surgery.Methods The FDM 3D printing was employed to make standard geometric shape models and maxillary models.After the surface finish of both models being observed,the contour data and fineness of geometric models,as well as the distance error of bony markers between maxillary models and jaw bones specimen were measured.Results Within the 3D printing standard geometric model,the fiber arrange horizontally in X-Z,Y-Z surface and crosswise in X-Y surface,and the accuracy errors range from-1.67％ to 1.47％.Moreover,the maximum resolution was 0.25 mm in X and Y axis,and 0.50 mm in Z axis.Within the maxillary model,the distance error of bony markers range from-0.08 ％ to 1.96 ％,and the mean errors were 1.59 ％,0.86％,0.42％ in X,Y and Z axis respectively.The mean error in X axis was significantly larger than that in Y or Z axis (P＜0.05).Conclusion 3D printing maxilla models may possess high accuracy and apply to clinical practice.

Objective To identify clinicopathologic characteristics and prognostic factors through a retrospective analysis of 404 colon cancer patients.Methods A total of 404 patients(209 of them were followed up with inquisition) with colon cancer were surgically treated from 1993 to 2003 and studied by univariate and multivariate analysis.Results Using univariate analysis age of patients,it was found that differentiation degree of the tumors,lymphatic invasion,abdominal and distant metastases,TNM stage and adjuvant radiotherapy were associated with outcome.(2)Multivariate analysis showed that only abdominal and distant metastases and TNM stage were associated with prognosis.Conclusion Multivariate analysis proved following list are independent prognostic factors: abdominal,distant metastases and TNM stage.

AIM: To investigate the feasibility of reendothelialization of the injured arterial wall by autologous endothelial cell transplantation and their influences on neointima proliferation. METHODS: New Zealand white rabbits (n=30) were subjected to bilateral iliofemoral artery balloon injury. Cultured, autologous venous endothelial cells were immediately transplanted into one vessel(transplantation group), whereas the contralateral artery received medium only(control group). Reendothelialization of the injured arterial wall was analysed 4 hours or 4 days after cell transplantation by fluorescent tracing、scanning electron microscope(SEM) and Evans blue staining. Pathology analysis was employed 28 days after cell transplantation to evaluate neointima proliferation. RESULTS: The transplanted endothelial cells had adhered into the aterial wall 4 hours after transplantation and began to attach and spread 4 days later. A number of fluorescent labeling endothelial cells were observed in the endothelial injured arterial wall. The vessels in control group were stained nearly completely by Evans blue, whereas about 60% area was not stained in transplantation group. Pathological examination demostrated that neointimal area and maximal intima thickness in transplantation group significant decreased than those in control. CONCLUSION: Autologus endothelial cells were effectively transplanted into the injured arterial wall by balloon catheter, and it can relieve neointima proliferation in the long time.