Spectrophotometric seawater pH measurement system is an urgent need of device due to its quick speed and high precision. Based on spectrophotometric method and flow injection analysis technique, an automated system for pH measurement of seawater was developed by integrating pump and valve flow path, LED light source, flow cell and spectrophotometer. This measurement system effectively avoided bubbles. The indicator of concentration gradient in the seawater sample was used to correct for the pH perturbation caused by the indicator, thus the operation of system was simple and convenient. with this system, only 1. 5 min was needed for a sample measurement with a precision of 0. 0013 pH units and an offset of 0. 0059 pH units. This system could be used for the rapid determination of pH of seawater collected by laboratory or research ship with high precision pH values.

Objective To investigate the expression and significance of γH2AX in cervical squamous carcinoma.Methods Firstly,DNA were extracted from 74 cervical squamous carcinoma samples and PCR were tested for HPV infection.Secondly,formalin-fixed paraffin-embedded tissue sections (4 μm)were stained with H&E method to detect cervical lesions grading.Thirdly,HPV16 DNA were examined by in situ hybridization(ISH) and γH2AX,p16 were examined by immunohistochemical (IHC) staining.Then,30 cases typical tissue sections in which including the normal cervical tissue,cervical intraepithelial neoplasia and cervical carcinoma in situ were selected for comparing the HPV DNA loading,and the γH2AX and,pl6 expression.Finally,the feasibility of γH2AX serving as a biomarks in HPV infection-related cervical carcinogenesis were analyzed.Results In this study,HPV infection ratio is 98.65％,and HPV16 is the most common type with 74.32％ infection.In situ hybridization showed no HPV16 DNA exist in normal cervical tissues and CINI.In CIN Ⅱ HPV DNA exist mainly as episomal DNA.With the increasing of cervical lesions grade,HPV DNA was integrated into chromosome steadily.The expression of γH2AX and pl6 were positively associated with grading of cervical lesions.HPV DNA and γH2AX protein co-exist primarily in the prickle cell layer and the granular cell layer.The HPV DNA and p16 protein exist in different cell layer.Conclusion γH2AX may be employed as a biomarker for HPV positive cervical carcinogenesis.