ABSTRACT
Ankylosing spondylitis (AS) combined with spinal fractures with thoracic and lumbar fracture as the most common type shows characteristics of unstable fracture, high incidence of nerve injury, high mortality and high disability rate. The diagnosis may be missed because it is mostly caused by low-energy injury, when spinal rigidity and osteoporosis have a great impact on the accuracy of imaging examination. At the same time, the treatment choices are controversial, with no relevant specifications. Non-operative treatments can easily lead to bone nonunion, pseudoarthrosis and delayed nerve injury, while surgeries may be failed due to internal fixation failure. At present, there are no evidence-based guidelines for the diagnosis and treatment of AS combined with thoracic and lumbar fracture. In this context, the Spinal Trauma Academic Group of Orthopedics Branch of Chinese Medical Doctor Association organized experts to formulate the Clinical guideline for the diagnosis and treatment of adult ankylosing spondylitis combined with thoracolumbar fracture ( version 2023) by following the principles of evidence-based medicine and systematically review related literatures. Ten recommendations on the diagnosis, imaging evaluation, classification and treatment of AS combined with thoracic and lumbar fracture were put forward, aiming to standardize the clinical diagnosis and treatment of such disorder.
ABSTRACT
The ablated aerosols of biological matrix sample were studied using 213 nm nanosecond laser ablation system.The stable signal intensity and high sensitivity were obtained when the laser energy was 25%, the spot size was 200 μm, the scan rate was 20 μm/s, the frequency was 20 Hz and the carrier gas was 700 mL He + 700 mL Ar.Relative fractionation index of 56 elements were investigated and 31P as the internal standard element was selected under the optimized laser ablation conditions.The results showed that particle size of the biological sample was 3 μm, which was larger compared with NIST 610 sample.Element fractionation in biological sample was smaller than in glass sample, and relative fractionation index of most elements attained 1.0 ± 0.1.Element fractionation mechanism of biological sample was discussed.The possible reason why the relative fractionation index in biological sample with large particle size did not significantly increase compared to the glass sample is that the 3-μm particles entered into ICP can be atomized.On the other hand, enrichment effect for large ablation particles was relatively small.Further study of the influence factors of fractionation effect indicated that, the fractionation effect had relations with laser ablation energy, laser frequency and scan rate, negatively relation with the oxide boiling point, and positively relation with oxide bond energy and ionization energy.
ABSTRACT
Laser ablation inductively coupled plasma mass spectrometry ( LA_ICP_MS ) was applied for the determination of doping element chromium( Cr) content and distribution in Cr∶ZnSe crystals. Several different Cr∶ZnSe crystals were prepared by diffusion method as reference material to solve the problem of accurate quantization. The homogeneity of Cr in these samples was characterized by LA_ICP_MS and the concentrations achieved by inductively coupled plasma atomic emission spectrometry ( ICP_AES ) . With signal pot and line scan sampling, the present method provided effective position and content distribution information of Cr in ZnSe crystals, achieved the in situ analysis. The correlation coefficient of Cr in calibration curve was 0. 9992 and the detection limit was 0. 08 mg/kg. It could provide effective means for the distribution statistics of doping element in different growth condition crystals.