Authentication of ST25 rice using temperature-perturbed Raman measurement with variable selection by Incremental Association Markov Blanket.

A temperature-perturbed transmission Raman measurement was demonstrated for the discrimination of ST25 and non-ST25 rice samples. ST25 rice is a premium long-grain Vietnamese rice with the aroma of pandan leaves and the scent of early sticky rice. Raman spectra of rice samples were acquired with temperature perturbation ranging from 20 to 50 °C, and the variables (intensities of peaks) with greater discrimination were selected from the spectra using Incremental Association Markov Blanket (IAMB) for authentication. The combination of four, seven, and four variables selected from the spectra at 20, 30, and 50 °C, respectively, yielded the highest accuracy of 97.9%. The accuracies in the single-temperature measurements were lower, suggesting that the combination of mutually complementary spectral features acquired at these temperatures is synergetic to recognize the compositional differences between two sample groups, such as in the amylose/amylopectin ratio and the protein constituent.

Temperature-driven coordination of circadian transcriptome regulation.

The circadian rhythm is an evolutionarily-conserved molecular oscillator that enables species to anticipate rhythmic changes in their environment. At a molecular level, the core clock genes induce a circadian oscillation in thousands of genes in a tissue-specific manner, orchestrating myriad biological processes. While studies have investigated how the core clock circuit responds to environmental perturbations such as temperature, the downstream effects of such perturbations on circadian regulation remain poorly understood. By analyzing bulk-RNA sequencing of Drosophila fat bodies harvested from flies subjected to different environmental conditions, we demonstrate a highly condition-specific circadian transcriptome. Further employing a reference-based gene regulatory network (Reactome), we find evidence of increased gene-gene coordination at low temperatures and synchronization of rhythmic genes that are network neighbors. Our results point to the mechanisms by which the circadian clock mediates the fly's response to seasonal changes in temperature.

Discrimination of adulterated milk using temperature-perturbed two-dimensional infrared correlation spectroscopy and multivariate analysis.

The discrimination method for adulterated milk is proposed based on temperature-perturbed two-dimensional (2D) infrared correlation spectroscopy and N-way partial least squares discriminant analysis (NPLS-DA). Two brands of pure and adulterated milk samples were prepared. The mid-infrared spectra of all samples were obtained from 30 â„ƒ to 55 â„ƒ with an interval of 5 â„ƒ. Under the perturbation of temperature, synchronous 2D correlation spectra were calculated to build discrimination models of pure milk and adulterated milk. In comparison, the NPLS-DA models were built based on three-dimensional (3D) stacked map (sample × temperature × wavenumber variable). For the NPLS-DA models of two brands of milk, the discrimination accuracy of unknown samples in the prediction set is 100% using temperature-perturbed 2D infrared correlation spectra, versus 77.8% using conventional 3D stacked map. The proposed method can be used as an alternative way for classifying pure and adulterated milk.

2D Correlation Spectroscopy (2DCoS) Analysis of Temperature-Dependent FTIR-ATR Spectra in Branched Polyethyleneimine/TEMPO-Oxidized Cellulose Nano-Fiber Xerogels.

Fourier transform infrared spectroscopy in attenuated total reflectance geometry (FTIR-ATR), combined with a 2D correlation analysis, was here employed to investigate temperature-induced spectral changes occurring in a particular type of novel cellulosic-based nano-material prepared using 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) oxidized and ultra-sonicated cellulose nano-fibers (TOUS-CNFs) as three-dimensional scaffolds, and branched polyethyleneimine (bPEI) as cross-linking agent. The aim was to highlight the complex sequential events involving the different functional groups of the polymeric network, as well as to gain insight into the interplay between the amount of bPEI and the resulting sponge-like material, upon increasing temperature. In this framework, synchronous and asynchronous 2D spectra were computed and analyzed in three wavenumber regions (900-1200 cm-1, 1500-1700 cm-1 and 2680-3780 cm-1), where specific vibrational modes of the cellulosic structure fall, and over a T-range between 250 K and 340 K. A step-by-step evolution of the different arrangements of the polymer functional groups was proposed, with particular regard to how the cooperativity degree of inter- and intramolecular hydrogen bonds (HBs) changes upon heating. Information acquired can be useful, in principle, in order to develop a next-generation, T-sensitive novel material to be used for water remediation applications or for drug-delivery nano-vectors.

Enhanced identification of defective pre-coated paints on metal through simple temperature-perturbed infrared measurement in conjunction with two-trace two-dimensional correlation analysis.

A promising infrared (IR) spectroscopic method able to effectively identify defective pre-coated metal (PCM), a pre-painted metal panel, has been demonstrated. A temperature-perturbed IR measurement in conjunction with a two-trace two-dimensional (2T2D) correlation analysis was proposed as a strategy for enhancing defect identification. Our objectives were to induce dissimilar temperature-driven structural variations of base paints and added components, to recognize dissimilarities by 2T2D correlation analysis, and to use subsequent 2T2D correlation features to identify sample defects. For the exploratory examination, three defect cases were studied: 1) grey-silver PCMs with and without phosphate epoxy (2.0%), 2) normal and violet colorant-contaminated (0.2%) black PCMs, and 3) normal, violet (0.5%), and yellow colorant-contaminated (0.1%) white PCMs. The IR spectral features of the PCMs collected at 20 and 50 °C were different due to the temperature-dependent structural variations. Initial measurements at 50 °C allowed discrimination of normal and violet colorant-contaminated black PCMs. When using 2T2D slice spectra obtained from 2T2D correlation analysis using the spectra measured at the two temperatures, violet- as well as yellow colorant-contaminated white PCMs were identified, while these were unclear in the measurements at either 20 or 50 °C. The effective capture of dissimilar temperature-driven spectral variations of base paint and colorants (contaminants) by 2T2D correlation analysis was responsible for the improved defect identification.

Impacts of diel temperature variations on nitrogen removal and metacommunity of anammox biofilm reactors.

The influence of diel temperature variations (DTVs) on nitrogen removal and bacterial communities was investigated in two parallel anammox reactors (i.e., control and DTV reactors). The control reactor was operated at a constant temperature of 30 °C, whereas the DTV reactor was operated in a temperature fluctuation mode with a cycle of 12/12 h of high/low temperatures. Nine water temperature variations for the day/night periods were set from 30/30 °C (i.e., Δ0 °C) to 38/22 °C (i.e., Δ16 °C). An increase in DTVs from Δ8 °C (34/26 °C) to Δ16 °C (38/22 °C) caused a significant decline in reactor performance and a shift in bacterial diversity. Compared to the control reactor, for instance, nitrogen removal efficiency decreased (P < 0.05) when temperature fluctuations exceeded Δ8 °C in the DTV reactor with a decreasing ΔNO3-/ΔNH4+ ratio (from 0.21 ±â€¯0.15 to 0.16 ±â€¯0.04). The results of 16S rRNA gene sequencing showed that the initial disturbance of temperature variations led to increased levels of bacterial diversity (i.e., alpha diversity) and decreased community levels of anammox consortia whereas they slightly recovered at the end of each DTV phase. Notably, Candidatus Jettenia was more sensitive to strong water temperature fluctuations, with the lower relative abundance at Δ14 °C (17.11 ±â€¯5.01%) and Δ16 °C (17.83 ±â€¯7.22%) than at Δ4 °C (39.82 ±â€¯0.01%). In contrast, Ca. Brocadia and Ca. Kuenenia had higher relative abundance at Δ14 °C (i.e., 0.24 ±â€¯0.07% and 0.09 ± 0.02%, respectively) and Δ16 °C (i.e., 0.28 ±â€¯0.05% and 0.12 ± 0.03%, respectively) compared to that at Δ4 °C (i.e., 0.15 ±â€¯0.04% and 0.04 ± 0.01%, respectively). Nitrifiers (i.e., unidentified_Nitrospiraceae and Nitrosomonas) and denitrifiers (i.e., Denitratisoma) were also capable of tolerating high temperature perturbations. Overall this study furthers our knowledge of responses of the microbial ecology of anammox bacteria to DTVs in anammox processes, which could aid us in optimizing anammox-related wastewater treatment systems and in understanding the nitrogen cycles of natural ecosystems.