Effects of femtosecond laser treatment on surface characteristics and flexural strength of zirconia / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the effects of femtosecond laser treated microgrooved surface on microscopic topography, phase transformation, and three-points flexural strength of zirconia, and to provide reference for surface microstructure optimization of zirconia implant.@*METHODS@#According to different surface treatment methods, 57 computer aided design/computer aided manufacture (CAD/CAM) zirconia bars (20.0 mm×4.0 mm×1.4 mm) were evenly divided into three groups: sintered group, no treatment after sintering, taken as control; sandblasted group, sandblasted with 110 μm aluminium oxide (Al2O3) after sintering; microgrooved group, femtosecond laser fabricated microgrooves with 50 μm width, 30 μm depth, and 100 μm pitch. Surface microscopic topography was observed with scanning electron microscope (SEM) and 3D laser microscope. Further, surface roughness in each group and microgroove size were measured. Crystal phase was analyzed with X-ray diffraction. Specimens were subjected to three- points flexural strength test, and Weibull distribution was used to analyze their strength characteristics.@*RESULTS@#SEM showed that sintered surface was flat with clear grain structure; sandblasted surface exihibited bumps and holes with sharp margins and irregular shape; microgrooves were regularly aligned without evident defect, and nano-scale particles were observed on the surface inside of the microgrooves. Ra value of microgrooved group [(9.42±0.28)] μm was significantly higher than that of sandblasted group [(1.04±0.03) μm] and sintered group [(0.60±0.04) μm], and there was statistical difference between sandblasted group and sintered group (P < 0.001). The microgroove size was precise with (49.75±1.24) μm width, (30.85±1.02) μm depth, and (100.58±1.94) μm pitch. Crystal phase analysis showed that monoclinic volume fraction of sandblasted group (18.17%) was much higher than that of sintered group (1.55%), while microgrooved group (2.21%) was similar with sintered group. The flexural strength of sandblasted group (986.22±163.25) MPa had no statistical difference with that of sintered group (946.46±134.15) MPa (P=0.847), but the strength in microgrooved group (547.92±30.89) MPa dropped significantly compared with the other two groups (P < 0.001). Weibull modulus of sintered, sandblasted, microgrooved groups were 7.89, 6.98, and 23.46, respectively.@*CONCLUSION@#Femtosecond laser was able to form micro/nanostructured microgrooves on zirconia surface, which deleteriously affected the flexural strength of zirconia.

Association of interleukin-10 gene polymorphism with cachexia in patients with gastric cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate whether the single nucleotide polymorphisms (SNPs) at -1082, -819 and -592 of interleukin-10 gene and its haplotype are associated with cachexia in patients with gastric cancer.</p><p><b>METHODS</b>Radioimmunoassay was used to examine the serum levels of IL-10 in 223 patients with gastric cancer. The single nucleotide polymorphisms (SNPs) of IL-10 gene -1082G/A, -819T/C and -592A/C were analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).</p><p><b>RESULTS</b>The serum levels of IL-10 were significantly higher in patients with cachexia than those without (P < 0.001). An increased frequency of -1082G allele was noted in patients with cachexia (P = 0.049). The frequencies of -1082AG and -819CC genotypes were elevated in patients with cachexia than those without (P = 0.036, 0.024). In a logistic regression analysis adjusted for actual weight, carcinoma location and stage, the -1082AG genotype was associated with an odds ratio of 1.989 (95%CI, 1.041 - 3.802, P = 0.037), and the -819CC genotype with an odds ratio of 3.393 (95%CI, 1.298 - 8.871, P = 0.013) for cachexia. Furthermore, haplotype analysis revealed that G1082C819C592 haplotype was associated with a significantly increased risk of cachexia (OR = 2.21; 95%CI, 1.14 - 4.30; P = 0.02).</p><p><b>CONCLUSION</b>Our results suggest that the gene haplotype of IL-10 contributes to the occurrence of cachexia in patients with gastric cancer in Chinese population.</p>