[The validation of the effect of correcting spectral background changes based on floating reference method by simulation].

There are some challenges in near-infrared non-invasive blood glucose measurement, such as the low signal to noise ratio of instrument, the unstable measurement conditions, the unpredictable and irregular changes of the measured object, and etc. Therefore, it is difficult to extract the information of blood glucose concentrations from the complicated signals accurately. Reference measurement method is usually considered to be used to eliminate the effect of background changes. But there is no reference substance which changes synchronously with the anylate. After many years of research, our research group has proposed the floating reference method, which is succeeded in eliminating the spectral effects induced by the instrument drifts and the measured object's background variations. But our studies indicate that the reference-point will changes following the changing of measurement location and wavelength. Therefore, the effects of floating reference method should be verified comprehensively. In this paper, keeping things simple, the Monte Carlo simulation employing Intralipid solution with the concentrations of 5% and 10% is performed to verify the effect of floating reference method used into eliminating the consequences of the light source drift. And the light source drift is introduced through varying the incident photon number. The effectiveness of the floating reference method with corresponding reference-points at different wavelengths in eliminating the variations of the light source drift is estimated. The comparison of the prediction abilities of the calibration models with and without using this method shows that the RMSEPs of the method are decreased by about 98.57% (5%Intralipid)and 99.36% (10% Intralipid)for different Intralipid. The results indicate that the floating reference method has obvious effect in eliminating the background changes.

Application of Difluoromethyl Isosteres in the Design of Pesticide Active Molecules.

Difluoromethyl (CF2H) groups have been found in many listed pesticides due to their unique physical and chemical properties and outstanding biological activity. In pesticide molecules, compared with the drastic changes brought by trifluoromethyl, difluoromethyl usually moderately regulates the metabolic stability, lipophilicity, bioavailability, and binding affinity of compounds. Therefore, difluoromethylation has become an effective means to modify the biological activity of pesticide molecules. This paper reviews the representative literatures and patents containing difluoromethyl groups in the past 10 years, and introduces the research progress. The aim is to provide an effective reference value for the study of difluoromethyl in pesticides.

Image recognition technology provides insights into relationships between anthocyanin degradation and color variation during jet drying of black carrot.

To identify interesting relationships between anthocyanin degradation and color variation during food processing, black carrot slice (BCS) was dried by air-impingement jet drying (AIJD) and hot air drying (HAD). AIJD was a better technology for drying BCS than HAD. Results of colorimeter determination showed that the color of BCS was significantly changed during AIJD at 50, 60 and 70 °C. UHPLC-QqQ-MS/MS analysis found that AIJD-induced degradations of main BCS anthocyanins, cyanidin-3-xylosyl(feruloylglucosyl)galactoside and cyanidin-3-xylosyl(sinapoylglucosyl)galactoside, belonged to non-spontaneous endothermic reactions, which followed the 0.5- and 1-order kinetic equations, respectively. Anthocyanin content and colors obtained from colorimeter presented strong positive correlation, particularly the a* and chroma values. We further developed a Python script based on image recognition technology to visualize the correlation matrixes between the anthocyanin contents and colors of BSC images. The plots revealed that strong positive correlations between anthocyanins and colors primarily concentrated in the sample's periphery following a concentric pattern.

Chemometric analysis illuminates the relationship among browning, polyphenol degradation, Maillard reaction and flavor variation of 5 jujube fruits during air-impingement jet drying.

This study was designed to reveal the relationship among browning, polyphenol degradation, Maillard reaction (MR) and flavor variation in jujube fruit (JF) during air-impingement jet drying (AIJD). Five kinds of JFs were dried by AIJD at 60 °C and vacuum freeze drying. Colorimeter and chemometric analysis found that AIJD induced color changes of JF pulp and peel. AIJD also reduced the total polyphenols content and total flavonoids levels in JF. The Fe3+ reducing capacity and 2,2'-Azinobis-(3-ethylbenzothiazoline-6-sulphonate) cationic radical scavenging capacity of JF were reduced by 31.6% and 8.2%, respectively. Seven polyphenols were identified in JF, and epicatechin was found related to change of JF pulp color by sparse partial least square (sPLS). sPLS revealed that 3-deoxy glucosone, N-ε-carboxymethyl-l-lysine and 5-hydroxymethylfurfural associated with JF color. sPLS found that MR generated 3-methyl-butanoic acid and cyclobutanone during AIJD of JF. Chemometrics is an effective tool to disclose mechanism of color changes in food.

Fructo-oligosaccharide enhanced bioavailability of polyglycosylated anthocyanins from red radish via regulating gut microbiota in mice.

The anthocyanins from red radish (ARR) rich in polyglycosylated pelargonidin glucosides were used as pigment. However, bioavailability of anthocyanins was considered at low level. This work examined the intensive effects of fructo-oligosaccharide (FOS) on ARR bioavailability. Pelargonidin, cyanidin and pelargonidin-3-glucoside showed higher level in serum of mice fed with FOS together with ARR for 8 weeks than that fed with only ARR. Co-ingestion of FOS and ARR more effectively elevated the hepatic antioxidant activity by increase in total antioxidant capacity and activities of superoxide dismutase and glutathione peroxidase when compared with intake of ARR. FOS also markedly increased pelargonidin level in cecum of mice. 16S RNA sequencing found that Bacteroides genus play an important role in FOS elevating bioavailability of ARR. Fecal bacteria transplantation verified the positive effects of FOS on ARR bioavailability. These results suggested that combined ingestion of FOS and ARR is effective strategy for bioactivity of ARR.

The complete chloroplast genome sequence of Annamocarya sinensis (Juglandaceae), an Endangered species endemic to Yunnan Province, China.

Annamocarya sinensis, a plant species with extremely small populations endemic to Xichou county of Yunnan province, has been classified as a national second-class protected wild plant. In this study, we assembled its complete chloroplast genome. The total genome size of A. sinensis was 158,484 bp in length, containing a large single-copy region of 89,871 bp, a small single-copy region of 20,558 bp, and a pair of inverted repeat regions of 24,029 bp. The all GC content of A. sinensis chloroplast genome was 36.2%. It encodes a total of 114 unique genes, including 79 protein-coding genes, 31 tRNA genes, and four rRNA genes. Eleven genes contain a single intron, and three genes have two introns. Phylogenetic analysis results strongly supported that Annamocarya sinensis was closely related to Carya kweichowensis.

Discussion on the validity of NIR spectral data in non-invasive blood glucose sensing.

In this paper, the effects of two-dimensional correlation spectroscopy (2DCOS) on chance correlations in the spectral data, generated from the correlations between glucose concentration and some undesirable experimental factors, such as instrument drift, sample temperature variations, and interferent compositions in the sample matrix, are investigated. The aim is to evaluate the validity of the spectral data set, instead of assessing the calibration models, and then to provide a complementary procedure for better verifying or rejecting the data set. It includes tracing back to the source of the chance correlation on the chemical basis, selecting appropriate preprocessing methods before building multivariate calibration models, and therefore may avoid invalid models. The utility of the proposed analysis is demonstrated with a series of aqueous solutions using near-infrared spectra over the overtone band of glucose. Results show that, spectral variations from chance correlations induced by those experimental factors can be determined by the 2DCOS method, which develops avenues for prospectively accurate prediction in clinical application of this technology.