BACKGROUND:For severe thoracolumbar compression fracture (>1/3 compression), ideal therapeutic method is minimal y invasive internal fixation, which has good biomechanical functions. Moreover, bone graft is reliable. Injured vertebra reduction and bone graft stability achieved. Motor unit of spinal column and normal physiological function were retained, resulting in lessening nearby segmental degeneration.
OBJECTIVE:To discuss the design of single vertebrae internal fixation system and evaluate its biomechanical performance which apply to treat thoracolumbar compression fracture by endoscope.
METHODS:A brand-new single vertebrae internal fixation system was designed in accordance with data of anatomic measurement of adult thoracolumbar vertebra. Six fresh adult corpse specimens were prepared to produce models of L 1 compression fracture, and assigned to control group, fracture injury group, single vertebrae internal fixation system group, AF reduction internal fixation group and anterior plate internal fixation group.Three-dimensional movement range experiments were conducted separately.
RESULTS AND CONCLUSION:The biomechanical comparison showed that there was no significant difference in three-dimensional range of motion among single vertebrae internal fixation system group (anteflexion, left and right lateroflexion), AF reduction internal fixation group and anterior plate internal fixation group (P>0.05). However, range of motion significantly increased at backward extension, left and right rotation (P<0.05). Results suggested that the design of single vertebrae internal fixation system was novel and the system had good biomechanical performance at anteflexion, left and right lateroflexion. However, it needs to be improved in which lacks of stability of extension and rotation.

Soil archaea and fungi play important roles in the greenhouse soil ecosystem. To develop and apply rich microbial resources in greenhouse ecological environment, and to understand the interaction between microbes and plants, we constructed archaeal 16S rRNA and fungal 18S rRNA gene libraries to analyze the compositions of archaeal and fungal communities. Total greenhouse soil DNA was directly extracted and purified by skiving-thawing-lysozyme-proteinase K-SDS hot treatment and treatment of cetyltriethylammnonium bromide (CTAB). After PCR amplification, retrieving, ligating, transforming, screening of white clones, archaeal 16S rRNA and fungal 18S rRNA gene libraries were constructed. The sequences of archaea and fungi were defined into operational taxonomic units (OTUs) when 97% similarity threshold for OTU assignment was performed by using the software DOTUR. Phylogenetic analysis showed that crenarchaeota and unidentified-archaea were the two major sub-groups and only a few of euryarchaeota existed in the archaeal clone library, total 45 OTUs. All the crenarchaeota belonged to thermoprotei; except for Basidiomycotina, the other four sub-group fungi were discovered in the fungal library, total 24 OTUs. The diversities of archaea were very abundant and a few euryarchaeota (methanebacteria) existed in the archaeal clone library, it might be directly related to the long-term high temperature, high humidity, and high content of organic matter. The limitation of oxygen was the other reason for causing this phenomenon; Ascomycotina (over 80%) was the dominant sub-groups in fungal library. It was because most of the plant fungal diseases belonged to soil-borne diseases which gone through the winter by the ways of scierotium or perithecium and became the sources of primary infection.
Archaea ; genetics ; growth & development ; Biodiversity ; Cloning, Molecular ; Cucumis sativus ; growth & development ; Fungi ; genetics ; growth & development ; Gene Library ; Genes, rRNA ; Microclimate ; Phylogeny ; Plant Roots ; microbiology ; RNA, Archaeal ; genetics ; RNA, Fungal ; genetics ; RNA, Ribosomal, 16S ; genetics ; RNA, Ribosomal, 18S ; genetics ; Soil Microbiology

Objective To explore the feasibility and effect of 3D modeling and printing technology in constructing bone fracture models and assisting clinical teaching at the department of traumatic orthope-dics. Methods CT scan images of bone fractures were reconstructed by Mimics software. The digital 3D bone fracture models were constructed and the interactive multimedia teaching videos were output. More-over, all bone fracture models were printed by using fusion deposition modeling (FDM). At the end of the teaching course, a questionnaire survey was conducted to evaluate the teaching effect. Results The digital models of common bone fractures at the department of traumatic orthopedics were established, and the in-teractive multimedia teaching videos were output. A traumatic orthopedic teaching model with a 1∶1 scale was printed out. The questionnaire survey indicated that the application of 3D modeling and printing tech-nology to build bone fracture model with PPT teaching can obviously improve students' understanding and mastery of relevant theoretical knowledge. They helped students better remember the type of bone fractures and how to choose the correct internal fixation methods. The teaching effect was satisfactory. Conclusions 3D modeling and printing technology was applied to build bone fracture models to assist clinical teaching at the department of traumatic orthopedics. It was found that the printed 3D bone fracture models can stimulate students' enthusiasm for learning and improve their learning effect. This method has good application value.