ABSTRACT
Objective To compare the detection results of three kinds of automated nucleic acid purifiers, and to evaluate the detection performance of the domestic 2019-nCoV RNA purifier. Methods Three automated nucleic acid purifiers, namely A (imported), B (domestic), and C (domestic) automated nucleic acid extraction instruments, were used to purify nucleic acid. The Conchestan 2019-nCoV RNA (Liquid) quality control product S5 (batch number 202007002, reference level 1000cp/ml) was chosen as the experimental object. The quality control product was diluted in a series of 10 to 1000 times to prepare experimental samples of different concentrations. Among them, the A nucleic acid purifier used its own matching reagents, and the B and C purifiers belonged to a same manufacturer with different models and used their own supporting reagents as well as third-party reagents, to evaluate the anti-pollution ability, precision, accuracy, repeatability, detection limit and linear correlation. Results Using the imported brand A as a reference standard for comparison, when using reagents from B, the linear correlation between the two domestic nucleic acid purifiers and the imported equipment were 0.999, 0.915 (N-terminal), and 0.997, 0.825 (ORF1ab-terminal), respectively; when using the third-patty reagents, the linear correlation between the two domestic nucleic acid purifiers and the imported equipment were 0.999, 0.915 (N-terminal) and 0.997, 0.825 (ORF1ab-terminal), respectively. Conclusion The extraction of 2019-NCOV RNA by domestic nucleic acid purifiers can be fully automated with good correlation. The system performance is comparable to international standards. Moreover, the extraction time of the domestic nucleic acid purifiers is shorter than the imported one, which offers obvious advantages when the number of samples is large.
ABSTRACT
<p><b>OBJECTIVE</b>To analyze the geographic spatial patterns and risk areas of main digestive system cancers in Yiwu city.</p><p><b>METHODS</b>Newly diagnosed cases of esophageal, gastric and colorectal cancer during 2010-2014 were obtained from Yiwu Center for Disease Control and Prevention (CDC). The household registration population data in 2013 were obtained from public security bureau. Hierarchy clustering and partitioning regionalization method was used to generate geographic units. Global Moran's I was used to evaluate whether cancer incidence was significantly clustered in space, Anselin Local Moran's I was used to identify statistically significant hot spots, cold spots, and spatial outliers, and Spatial Scan Statistics was implemented to analyze the relative risk of cancers in different areas.</p><p><b>RESULTS</b>The 5-year average incidence of esophageal, gastric and colorectal cancers were 9.99/100 000, 34.01/100 000 and 31.46/100 000, respectively. Males showed significantly higher incidence than females. The incidence was heterogeneous throughout the study area. Spatial Scan analysis revealed that southern Yiwu presented a significantly higher male esophageal cancer (=1.78) and gastric cancer (=1.87) risk. The central area of Yiwu showed a significantly lower female esophageal cancer risk (=0.00) and male stomach cancer risk (=0.63) and the northern Yiwu exhibited a significantly lower female colorectal cancer risk (=0.48).</p><p><b>CONCLUSIONS</b>The incidence of main digestive tract cancers shows a heterogeneous distribution in Yiwu city.</p>
ABSTRACT
Objective Sporadic cases occurring in mall geographic unit could lead to extreme value of incidence due to the small population bases,which would influence the analysis of actual incidence.Methods This study introduced a method of hierarchy clustering and partitioning regionalization,which integrates areas with small population into larger areas with enough population by using Geographic Information System (GIS) based on the principles of spatial continuity and geographical similarity (homogeneity test).This method was applied in spatial epidemiology by using a data set of thyroid cancer incidence in Yiwu,Zhejiang province,between 2010 and 2013.Results Thyroid cancer incidence data were more reliable and stable in the new regionalized areas.Hotspot analysis (Getis-Ord) on the incidence in new areas indicated that there was obvious case clustering in the central area of Yiwu.Conclusion This method can effectively solve the problem of small population base in small geographic units in spatial epidemiological analysis of thyroid cancer incidence and can be used for other diseases and in other areas.