While the near infrared spectroscopy (NIRS) is used to measure the inhomogeneous samples with diffuse reflection mode, the accuracy and robustness of the calibration model is not quite good for the variation of spectrum scattering and absorption coefficient in those samples.Therefore, an establishment strategy of hybrid model based on homogeneous sample and calibration transfer method was proposed to solve the problem of detection inhomogeneous samples by NIRS.This work was focused on the tobacco leaf samples aspect.Three common calibration transfer methods, including Shenk′s patented algorithm (Shenk′s), piecewise direct standardization (PDS) and calibration transfer based on canonical correlation analysis (CTCCA), were used to construct two hybrid models of tobacco powder mixed with cut tobacco and tobacco powder mixed with tobacco flake samples to predict nicotine content in the samples of cut tobacco and tobacco flake.Experimental results showed that the hybrid model of adding some cut tobacco and tobacco flake samples to the powder model would get preferred prediction ability.Root mean square errors of cut tobacco and tobacco flake samples were reduced by 1.39% and 2.73%, respectively.This showed that the hybrid model was help for the improvement of the predicted results and the robustness of model.Moreover, CTCCA got the optimal performance between these three calibration transfer methods.Therefore, the scheme of building a hybrid model by NIRS homogeneous model and calibration transfer method to determinate the heterogeneous samples is feasible, which can accelerate the development of on-line near infrared spectroscopy technology and will provide reference for the share of near infrared spectral model.

OBJECTIVETo evaluate the association between the two single nucleotide polymorphisms located in catechol-O-methyltransferase (COMT) gene and type 2 diabetes mellitus (T2DM)in Han population in Guangdong province.

METHODSTwo tagSNPs (rs4646312 and rs4680) were picked out from COMT gene. Using the SNPscan(TM) Kit, SNP genotyping was then performed, in two cohorts, including 595 cases and 725 controls. Finally, Chi-square test, logistic regression model and other methods were employed for statistical analysis.

RESULTSThe frequencies of TT, CT and CC of rs4646312 appeared to be 304(51.1%), 234(39.3%)and 57 (8.6%) in cases, 323 (44.6%), 319 (44.0%) and 83(11.4%)in controls, respectively. The frequencies of GG,GA and AA of rs4680 were 311(52.4%), 236 (39.8%) and 46(7.8%)in cases, 417(57.7%), 265 (36.6%) and 41 (5.7%) in controls, respectively.

RESULTSshowed that SNP rs4646312 was significantly associated with T2DM both in allelic association analysis (P = 0.020,OR = 1.26, 95%CI:1.04-1.53)and in recessive model (P = 0.022, OR = 1.35, 95% CI:1.05-1.74)after adjustment for sex,BMI and TG. The association between rs4680 and T2DM was not significant, but BMI was remarkably different among the three genotypes of rs4680 after controlling for other factors.

CONCLUSIONSNP rs4646312 of COMT gene was associated with the increased risk of T2DM in Han population in Guangdong province. However, rs4680 was not significantly associated with T2DM.

Adult ; Aged ; Alleles ; Case-Control Studies ; Catechol O-Methyltransferase ; genetics ; Diabetes Mellitus, Type 2 ; etiology ; genetics ; Female ; Gene Frequency ; Genotype ; Humans ; Male ; Middle Aged ; Polymorphism, Single Nucleotide