A polyimide coated stir bar for sorptive extraction (SBSE) was prepared by immersion precipitation method, and evaluated by using 5 phenols and chlorinated phenols as model samples. The extraction efficiency of the prepared stir bar was the highest compared with commercial extraction phases of SBSE. Experimental parameters including stir speed, ionic strength, extraction temperature, extraction time, desorption temperature and time were optimized. Under the optimal conditions such as 100 mL of sample, 30 g of NaCl, extraction time of 30 min, stirring speed of 800 r/ min and at 25℃, the target compounds were recovered by thermal desorption at 300℃ for 4 min, more than two orders of magnitude of linearity was obtained (R≥0. 9995), LOQs (S/ N=10) were 0. 028-0. 123 μg/ L, and RSDs were in the range of 1. 6% -9. 7% . The polyimide SBSE coupled with gas chromatography-mass spectrometry was applied to the extraction/ enrichment and analysis of phenols in real samples, including tap water, sea water, and waste water. It was found that the polyimide SBSE showed high selectivity towards polar compounds and high thermostability up to 350℃.

A thermal desorption ( TD) device was developed and coupled to gas chromatography ( GC) or gas chromatography-mass spectrometry ( GC-MS ) for the qualitative and quantitative analysis of semi-volatile organic compounds on atmospheric particulate matters ( PM ) . The TD was operated by direct heating and placed on the GC injector, leading to high heating rate and easy transfer of analytes to GC without focusing of analytes by cold trap. For establishing the TD-GC method, the materials used for supporting PM samples, temperature and time of thermal desorption, and types of sample injection were investigated for detection of sixteen polycyclic aromatic hydrocarbons ( PAHs) and nine n-alkanes. The limits of detection of the proposed TD-GC method were in the range of 0. 014-0. 093 ng for PAHs, and 0. 016-0. 026 ng for n-alkanes, respectively, with the correlation coefficients of correlation above 0. 9975. The TD-GC method was applied to the determination of trace PAHs and n-alkanes on PM10 samples from three cities. The recoveries were in the range of 95%-135% ( PAHs) and 95%-115% ( n-alkanes) , respectively. Finally, the TD was coupled to GC-MS for comparison of the contents of PAHs and n-alkanes on PMx with different particulate size ( x=10 , 5, 2, 1, 0. 5, 0. 25, 0. 1).

Selective extraction of low molecular weight ( LMW) proteins and peptides from complex biological samples plays an important role in the discovery of useful biomarkers and signaling molecules. It is demonstrated that the unique pore structure of mesoporous material makes it efficient to enrich LMW proteins and peptides from complex matrixes. In this study, a mesoporous material, alkyl-diol@ phenyl-SiO2 , with modified exterior ( alkyl-diol group) and interior ( phenyl group) surfaces, was synthesized by co-condensation and post-grafting, and its characteristic was evaluated by FTIR and MS. The LMW proteins and peptides enriched by the alkyl-diol@phenyl-SiO2 mesoporous material could be easily eluted by organic solvents, which was compatible with the following detection by mass spectrometry ( MS ) . This new mesoporous material exhibited good selectivity for the extraction of LMW proteins and peptides ( less than 10 kDa) from complex biological samples.

Objective:To explore the effect of Wnt/β-catenin signaling pathway on growth plate development of tibial growth plate in young chronic renal failure (CRF) rats.Methods:Four-week-old male SD rats were randomly divided into control group and CRF group ( n=20/per group). Control group was intragastric administration with distilled water, and CRF group was given adenine suspension (150 mg·kg -1·d -1). All the young rats were sacrificed after continuous gavages for 6 weeks. The full length of tibia was compared between the two groups. The width of tibia proximal growth plates was measured by micro-CT scanning, and the width of the growth plate was also measured in histological sections. Chondrocytes isolated from growth plate in two groups were cultured in vitro to P3 generation. Immunohistochemical staining was used to detect the expression of collagen Ⅱ, matrix metalloproteinase 13 (MMP-13) and β-catenin in chondrocytes. Western blotting was used to detect the protein expressions of collagen Ⅱ, MMP-13 and β-catenin. Results:Compared with the control group, the tibial length of rats in the CRF group was shorter [(27.32±5.81) mm vs (35.43±3.61) mm, t=5.226, P<0.001], the width of growth plate in micro-CT picture was more narrow [(0.72±0.22) mm vs (1.13±0.27) mm, t=5.096, P<0.001], and the relative width of the growth plate was also more narrow ( t=6.744, P<0.001) in histological sections. The results of immunohistochemistry and Western blotting showed the expressions of collagen Ⅱ in the CRF group decreased significantly ( t=8.212, P<0.001), MMP-13 ( t=13.091, P<0.001) and β-catenin ( t=7.534, P<0.001) increased significantly compared the control group in chondrocytes. Conclusion:The Wnt/β-catenin signaling pathway is highly expressed in the tibial growth plate of young rats with chronic renal failure, which leads to accelerated degeneration and differentiation of chondrocytes and a closure tendency of growth plate.

Objective: To evaluate the usefulness of retroauricular hairline incision (RAHI) in partial superficial parotidectomy (PSP) by comparison with modified Blair incision (MBI). Methods: A retrospective analysis of 64 medical records for patients with benign parotid tumors who underwent partial superficial parotidectomy was undertaken (28 were in MBI group, 36 in RAHI group). Size and location of tumors, operative time, occurrence of facial nerve paralysis and Frey′s syndrome, and cosmetic outcomes were compared between RAHI and MBI groups. Results: Compared with MBI group, RAHI group showed better cosmetic results for benign parotid tumors in mean satisfaction score(P<0.001). There were no significant differences in size and location of tumors, operative time, incidence of transient or permanent facial nerve paralysis and Frey′s syndrome between two groups (P>0.05). Conclusions Partial superficial parotidectomy can be performed safely via RAHI in most cases of benign parotid tumors. Compared with MBI, RAHI for benign parotid tumorscan improve the cosmetic outcome, without increasing the operative time or operative morbidity.