UAV multispectral multi-domain feature optimization for the air-to-ground recognition of outdoor injured human targets under cross-scene environment.

Objective: UAV-based multispectral detection and identification technology for ground injured human targets, is a novel and promising unmanned technology for public health and safety IoT applications, such as outdoor lost injured searching and battlefield casualty searching, and our previous research has demonstrated its feasibility. However, in practical applications, the searched human target always exhibits low target-background contrast relative to the vast and diverse surrounding environment, and the ground environment also shifts randomly during the UAV cruise process. These two key factors make it difficult to achieve highly robust, stable, and accurate recognition performance under the cross-scene situation. Methods: This paper proposes a cross-scene multi-domain feature joint optimization (CMFJO) for cross-scene outdoor static human target recognition. Results: In the experiments, we first investigated the impact severity of the cross-scene problem and the necessity to solve it by designing 3 typical single-scene experiments. Experimental results show that although a single-scene model holds good recognition capability for its scenes (96.35% in desert scenes, 99.81% in woodland scenes, and 97.39% in urban scenes), its recognition performance for other scenes deteriorates sharply (below 75% overall) after scene changes. On the other hand, the proposed CMFJO method was also validated using the same cross-scene feature dataset. The recognition results for both individual scene and composite scene show that this method could achieve an average classification accuracy of 92.55% under cross-scene situation. Discussion: This study first tried to construct an excellent cross-scene recognition model for the human target recognition, named CMFJO method, which is based on multispectral multi-domain feature vectors with scenario-independent, stable and efficient target recognition capability. It will significantly improve the accuracy and usability of UAV-based multispectral technology method for outdoor injured human target search in practical applications and provide a powerful supporting technology for public safety and health.

Degradation of mirubactin to multiple siderophores with varying Fe(III) chelation properties.

Three siderophores mirubactins B-D (4-6) were identified as the degradation products of previously isolated mirubactin (1). Their structures were revealed by HR-ESI-MS/MS, NMR analyses, and density functional calculations, among which 4 contains an unusual cyclic amidine functionality. Cyclic voltammetry showed that 5 and 6 have reduced iron complexing capacity. Mirubactin (1) and Fe(III) could also form a stable complex, which may be an ingenious approach to compete for iron acquisition by the producing organisms.

[Effects of soil water stress and atmospheric CO2 concentration on photosynthetic and post-photosynthetic fractionation].

Analysis of plant photosynthesis and post-photosynthetic fractionation can improve our understanding of plant physiology and water management. By measuring δ13C in the atmosphere, and δ13C of soluble compounds in leaves and branch phloem of Platycladus orientalis, we examined discrimination pattern, including atmosphere-leaf discrimination during photosynthesis (ΔCa-leaf) and leaf-twig discrimination during post-photosynthesis (ΔCleaf-phlo), in response to changes of soil water content (SWC) and atmospheric CO2 concentration (Ca). The results showed that ΔCa-leaf reached a maximum of 13.06‰ at 95%-100% field water-holding capacity (FC) and Ca 400 µmol·mol-1, and a minimum of 8.63‰ at 35%-45% FC and Ca 800 µmol·mol-1. Both stomatal conductance and mesophyll cell conductance showed a significant linear positive correlation with ΔCa-leaf, with a correlation coefficient of 0.43 and 0.44, respectively. ΔCleaf-phlo was not affected by SWC and Ca. Our results provide mechanism of carbon isotopes fractionation and a theoretical basis for plant survival strategies in response to future climate change.

Novel methyl indolinone-6-carboxylates containing an indole moiety as angiokinase inhibitors.

A novel series of methyl indolinone-6-carboxylates bearing an indole moiety were identified as potent angiokinase inhibitors. The most active compound, A8, potently targeted the kinase activities of vascular endothelial growth factor receptors 2 and 3, and platelet-derived growth factor receptors α and ß, with IC50 values in the nanomolar range. In addition, A8 effectively suppressed the proliferation of human umbilical vein endothelial cells, and HT-29 and MCF-7 cancer cells, by inducing apoptosis. Compound A8 is thus a promising candidate for further investigation.

Characterization of heavy metal-resistant endophytic bacteria from rape (Brassica napus) roots and their potential in promoting the growth and lead accumulation of rape.

Two lead (Pb)-resistant endophytic bacteria were isolated from rape roots grown in heavy metal-contaminated soils and characterized. A pot experiment was conducted for investigating the capability of the two isolates to promote the growth and Pb uptake of rape from Pb-amended soil. The two isolates were identified as Pseudomonas fluorescens G10 and Microbacterium sp. G16 based on the 16S rDNA gene sequence analysis. Strains G10 and G16 exhibited different multiple heavy metal and antibiotic resistance characteristics and increased water-soluble Pb in solution and in Pb-added soil. Root elongation assays demonstrated increases in root elongation of inoculated rape seedlings compared to the control plants. Strain G16 produced indole acetic acid, siderophores and 1-aminocyclopropane-1-carboxylate deaminase. Increases in biomass production and total Pb uptake in the bacteria-inoculated plants were obtained compared to the control. The two strains could colonize the root interior and rhizosphere soil of rape after root inoculation.

Improvement of rape (Brassica napus) plant growth and cadmium uptake by cadmium-resistant bacteria.

This study focuses on the screening of cadmium-resistance bacterial strains from heavy metal-polluted soils to examine their plant growth promotion and cadmium uptake in rape (Brassica napus). A large number of bacteria were isolated from heavy metal-polluted soil in Nanjing, China. Thirty isolates showing cadmium-resistance on Cd-amended medium were selected and evaluated for their potential to solubilize cadmium carbonate in solution culture. Atomic absorption spectrometer analysis showed variable amounts of water-soluble Cd (ranging from 24 to 117 mg l(-1)) released by the cadmium-resistant bacterial strains from cadmium carbonate. Qualitative analysis confirmed the presence of indole acetic acid as the auxin in the culture of these cadmium-resistant bacterial strains. Root elongation assay conducted on rape under gnotobiotic conditions demonstrated increases (up to 31%) in root elongation of inoculated rape seedlings compared to the control plants. Based upon cadmium-resistance, bio-activation of CdCO3 and growth-promoting activity, three isolates were selected for promoting plant growth and uptake of cadmium from cadmium-amended soil in pot experiments. Inoculation with the isolates was found to increase root dry weight (ranging from 8% to 20%) and shoot dry weight (ranging from 6% to 25%) of rape. An increase in cadmium content varying from 16 to 74%, compared to the non-inoculated control, was observed in rape plants cultivated in soil treated with 100 mgCd kg(-1) (as CdCl2) and inoculated with the isolates. The bacterial isolates were also able to colonize and develop in the rhizosphere soil of rape after root inoculation.