Real-Time Detection of Rice Growth Phase Transition for Panicle Nitrogen Application Timing Assessment

Nitrogen (N) topdressing at the early reproductive phase (ER) is beneficial for rice yield. However, the ER overlaps with the late vegetative phase (LV) and is, thus, difficult to be recognized by human observation. Therefore, this study aimed to establish a high-temporal-resolution approach to determine the LV and ER via hyperspectral proximal sensing. Firstly, this research measured the leaf cover area (LCA), leaf dry weight (LDW), chlorophyll content (SPAD), leaf N content (LNC), and leaf N accumulation (LNA) to investigate the physical and physiological changes of the rice plant during growth phase transition. It could be summarized that the LCA would be maximally extended before ER, the leaf growth would be retarded after LV, and leaves turned from green to yellowish-green resulting from N translocation. These phenomena were expected to be detected by the hyperspectral sensor. In order to capture the variation of spectral information while eliminating redundant hyperspectral wavelengths, feature extraction (FE) and feature selection (FS) were conducted to reduce the data dimension. Meanwhile, the implications of the features were also inferenced. Three principal components, which correlated with the rice plant’s physical and physiological traits, were extracted for subsequent modeling. On the aspect of FS, 402, 432, 579, and 696 nm were selected as the predictors. The 402 nm wavelength significantly correlated with leaf cover area to some extent (p < 0.09), and 432 nm had no significant correlation with all of the measured plant traits (p > 0.10). The 579 nm and 696 nm wavelengths were negatively correlated with SPAD and LNC (p < 0.001). In addition, 696 nm was also negatively correlated with LNA (p < 0.05). Finally, the logistic regression, random forest (RF), and support vector machine (SVM) algorithms were adopted to solve the binary classification problem. The result showed that the feature extraction-based logistic regression (FE-logistic) and support vector machine (FE-SVM) were competent for growth phase discrimination (accuracy > 0.80). Nonetheless, taking the detrimental effects of applying N at LV into consideration, the feature extraction-based support vector machine (FE-SVM) was more appropriate for the timing assessment of panicle fertilizer application (sensitivity > 0.90; specificity > 0.80; precision > 0.80).

The Dynamics of Mycoplasma gallisepticum Nucleoid Structure at the Exponential and Stationary Growth Phases

The structure and dynamics of bacterial nucleoids play important roles in regulating gene expression. Bacteria of class Mollicutes and, in particular, mycoplasmas feature extremely reduced genomes. They lack multiple structural proteins of the nucleoid, as well as regulators of gene expression. We studied the organization of Mycoplasma gallisepticum nucleoids in the stationary and exponential growth phases at the structural and protein levels. The growth phase transition results in the structural reorganization of M. gallisepticum nucleoid. In particular, it undergoes condensation and changes in the protein content. The observed changes corroborate with the previously identified global rearrangement of the transcriptional landscape in this bacterium during the growth phase transition. In addition, we identified that the glycolytic enzyme enolase functions as a nucleoid structural protein in this bacterium. It is capable of non-specific DNA binding and can form fibril-like complexes with DNA.

Effects of A site doping on the crystallization of perovskite films

The effects of A site doping on the crystallization, including the morphology and crystallinity of the PbI2 layer, nucleation and growth, phase transition and crystal orientation.

Crystallite growth, phase transition, magnetic properties, and sintering behaviour of nano-CuFe2O4 powders prepared by a combustionlike process

The synthesis of nano-crystalline CuFe2O4 powders by a combustion-like process isdescribed herein. Phase formation and evolution of the crystallite size during thedecomposition process of a (CuFe2)-precursor gel were monitored up to 1000 °C. Phase-purenano-sized CuFe2O4 powders were obtained after reaction at 750 °C for 2 h resulting in acrystallite size of 36 nm, which increases to 96 nm after calcining at 1000 °C. The activationenergy of the crystallite growth process was calculated as 389 kJ mol−1. The tetragonal -cubic phase transition occurs between 402 and 419 °C and the enthalpy change (dH) wasfound to range between 1020 and 1229 J mol−1 depending on the calcination temperature. The optical band gap depends on the calcination temperature and was found between 2.03 and1.89 eV. The shrinkage and sintering behaviour of compacted powders were examined. Denseceramic bodies can be obtained either after conventional sintering at 950 °C or after a twostepsintering process at 800 °C. Magnetic measurements of both powders and correspondingceramic bodies show that the saturation magnetization rises with increasing calcination-/sintering temperature up to 49.1 emu g−1 (2.1 μB f.u.−1), whereas the coercivity and remanencevalues decrease.