Experimental investigation of laser engraving quality on paper.

Laser engraving technology is a type of laser processing technology, widely used for product coding, marking, and so on. A large amount of research has reported the results of metal surface engraving; however, few research results, to the best of our knowledge, have provided theoretical support for the application of paper packaging laser engraving. In this paper, the quality of paper laser engraving is investigated by experimental methods. First, various phenomena appearing in paper carving were studied, including plant fiber burning, charcoal, and edge marks; second, the main factors affecting the quality of laser engraving are researched, and the influence of laser intensity and the preset width of carving marks on the engraving quality are discussed. The results show that the engraving precision is the best when the laser power is 11 W and the preset width is small (0.26 mm). Finally, the laser engraving precision of UV coated paper is studied, and the effect of UV material melting and secondary crystallization on engraving the quality of paper laser engraving quality is discussed. When the laser power is small, the maximum and minimum values of UV film melting and secondary crystallization engraving trace are relatively small as well; further, when the laser power increases, the maximum width of engraving is basically consistent with the preset width, and the precision of laser engraving is optimal.

[Analysis of the CYP1B1 gene mutation in primary congenital glaucoma patients of Hubei Han nationality].

OBJECTIVE: To identify novel CYP1B1 gene mutation in primary congenital glaucoma (PCG) patients of Hubei Han nationality and establish the possibility of gene diagnosis of PCG. METHODS: Forty-seven patients with PCG and 100 normal subjects were studied. Genomic DNA was extracted from the peripheral leukocytes of all subjects. Mutation in exon2 and exon3 of CYP1B1 gene was detected in patients and control subjects by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP), denaturing high performance liquid chromatograph (DHPLC), and direct sequencing DNA techniques. RESULTS: Compared to normal subjects, a novel mutation was first time identified by direct sequencing demonstrating a homozygous C-to-T transition at codon 385 (CTT to TTT) which produced L385F mutation of CYP1B1 gene in 7 of the 47 patients with PCG. CONCLUSIONS: The novel mutation in exon 3 of CYP1B1 found in PCG patients of Hubei Han nationality was probably pathological mutant gene by nature. It is important that further study be conducted to seek for the specific mutations of CYP1B1 gene and underlying pathological mechanism of PCG patients of Han nationality.