Search

The potential of laser-induced breakdown spectroscopy (LIBS) has been used to determine the micronutrients (iron and zinc) in wheat, which is a staple food and the most widely cultivated crop in Pakistan. Wheat samples consisted of commercial and candidate varieties and a fortified wheat flour (FWF). The LIBS spectrum were recorded from wheat flour pellets using a Q-switched Nd:YAG laser focused on the surface of the wheat sample. Twenty-five single shot spectra were recorded at different sites of the same pellet. The data were normalized to exclude shot-to-shot laser energy variations and then the averaged emission spectrum was used for further analysis. According to the NIST atomic data base and the related literature, the most intense emission lines of zinc at 202.54, 206.20 and 213.85 nm and iron at 238.20, 259.93, 275.57, 344.06 & 373.48/373.71 nm have been detected in the LIBS spectra of wheat genotypes, which has been used to determine their relative intensities. Significant variation among the genotypes was identified for these minerals. In addition, principal component analysis (PCA) has been performed to statistically classify the wheat varieties based on their iron and zinc emission intensities. The PCA grouped the data into clusters based on the similarities in their micronutrient. The highest zinc was identified in NR-488, Zincol-2006 and NARC-2011. Likewise, the strongest iron intensities were observed in FWF, Borlaug-2016 and NR-486. These findings may assist breeders in the selection of genotypes with high micronutrients coupled with high grain yield, and other desirable traits essential for variety release. The present study has validated LIBS as a characterization tool for inferring micronutrients in the staple food.

A quantitative analysis for the screening of immunoglobulin-G (IgG) positive human sera samples is presented for the dengue virus infection. The regression model was developed using 79 samples while 20 samples were used to test the performance of the model. The R-square (r 2) value of 0.91 was found through a leave-one-sample-out cross validation method, which shows the validity of this model. This model incorporates the molecular changes associated with IgG. Molecular analysis based on regression coefficients revealed that myristic acid, coenzyme-A, alanine, arabinose, arginine, vitamin C, carotene, fumarate, galactosamine, glutamate, lactic acid, stearic acid, tryptophan and vaccenic acid are positively correlated with IgG; while amide III, collagen, proteins, fatty acids, phospholipids and fucose are negatively correlated. For blindly tested samples, an excellent agreement has been found between the model predicted, and the clinical values of IgG. The parameters, which include sensitivity, specificity, accuracy and the area under the receiver operator characteristic curve, are found to be 100%, 83.3%, 95% and 0.99, respectively, which confirms the high quality of the model.

This study is intended to develop a multivariate statistical model for the prediction of nonstructural protein 1 (NS1) in dengue virus (DENV) infected blood serum in humans. The model has been developed on the basis of partial least squares regression using the Raman spectra of NS1 positive and NS1 negative samples. Human blood sera of 218 subjects is included in this study, of which 95 were NS1 positive and 123 were NS1 negative, which was confirmed with the enzyme linked immunosorbent assay method. For model development, 80 NS1 positive and 98 NS1 negative samples were used, while 40 DENV suspected samples were used for double blind testing of the model. This selection of samples was performed by the code in an automatic manner to avoid biasing. A laser at 785 nm was used as the excitation source to acquire Raman spectra of samples with an integration time of 15 s. The multivariate model yields coefficients of regression at corresponding Raman shifts. These coefficients represent changes in the molecular structures associated with NS1 positive and negative samples. The analysis of the regression coefficients which differentiate NS1 positive and NS1 negative groups shows an increasing trend for phosphatidylinositol, ceramide, and amide-III, and a decreasing trend for thiocyanate in the DENV infected serum. The R-squared value of the model was found to be 0.91, which is clinically acceptable. The blind testing of 40 suspected samples yields an accuracy, sensitivity, and specificity of about 100% each.