ABSTRACT
The unmet spectral mimicry of foliar green in camouflage materials is hampered by the lack of colorants with similar spectral properties to chlorophyll, resulting in substantial risks of exposure from hyperspectral target detection. By drawing inspiration from leaf chromogenesis, a microcapsule colorant with a chloroplast-like structure and chlorophyll-like absorption is developed, and a generic bilayer coating is designed to provide high spectral similarity to leaves with different growth stages, seasons, and species. Specifically, the microcapsule colorant preserves the monomeric absorption of the internal phthalocyanine and features the manufacturability of conventional pigments, such as amenability to painting and patterning, and compatibility to different substrates. The pigmented artificial leaves successfully deceive the hyperspectral classification algorithm in a foliar background, and outperforming the state-of-art spectral simulation materials. This coloration strategy expands the knowledge base of the spectral fine tuning of composite colorants, which are essential for their application in spectral-resolved optical materials.
Subject(s)
Algorithms , Chlorophyll , Capsules/analysis , Chlorophyll/chemistry , Plant Leaves/chemistry , Computer SimulationABSTRACT
Background: The study sought to investigate the effects of dexmedetomidine (DEX) on cognitive function after anesthesia and to examine its actual mechanism. Methods: A total of 48 rats were injected with d-galactose (D-gal) 1,000 mg·kg-1·d-1 and normal saline at the neck and back for 1 week to establish rats with mild cognitive impairment (MCI) and conduct behavioral tests. Sevoflurane was inhaled and DEX was pumped into each group respectively. Morris water maze (MWM) test was conducted 24 hours later. The inflammatory factors interleukin (IL)-1, interleukin (IL)-6, and a tumor necrosis factor (TNF)-α in brain homogenate were quantitatively measured by enzyme-linked immunosorbent assay (ELISA) on the next day. The apoptosis of hippocampal cells was observed by hematoxylin-eosin staining (HE staining). Results: In relation to the model establishment, we found that there was no significant difference in body weight and swimming speed before and after modeling. There was no statistically significant difference in the escape latency between Groups A, B, C, and D before modeling. After modeling, there was no statistical difference in the escape latency between Groups A, B, and C, but the difference was statistically significant when compared to Group D (P<0.05). In relation to the DEX intervention, we found that compared to Group C, MWM test performance in Groups A and B was considerably worse longer escape latencies and fewer platform crossings within 90 seconds), and were more significant in Group A. Compared with Group D, the levels of inflammatory cytokines of the brain homogenates were elevated, and this elevation was highest in Group A, followed by Group B; the pathological changes were consistent with changes in behavioral tests. In Group A, there were obvious disorders of glial cell arrangement, apoptosis and deletion. There was no significant change in Group D. And the changes of vertebral cells in Group B and Group C were slight, with orderly arrangement and intact cell structure. Conclusions: DEX inhibits the apoptosis of hippocampal cells and reduces the cognitive dysfunction of rats with MCI induced by D-gal via the inhibition of the release of inflammatory cytokines.
ABSTRACT
The emulation of the reflectance of green leaf in the solar spectral band (300-2500 nm) has garnered increasing attention from researchers. Currently, various materials have been proposed and investigated as potential bionic leaves. However, the problems such as poor weather durability, heavy metal pollution, and complex preparation technology still persist. Herein, a bionic leaf is prepared from an ultramarine green pigment as the functional material, polyvinylidene fluoride (PVDF) as the film-forming material, and LiCl as the humidizer. To prepare the ultramarine green pigment, the sulfur anion is added into the ß cage of the 4A zeolite. The mechanisms and properties were discussed based on X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and spectroscopic methods. The results show that the as-fabricated bionic leaf based on the 4A zeolite-derived ultramarine green pigment was able to demonstrate a high spectral similarity coefficient of 0.91 with the green leaf. Furthermore, the spectral similarity coefficient was increased to 0.94 after being subjected to a simulated rainforest environment for 48 h, which indicated its high weather durability.
ABSTRACT
Inkjet printing of functional materials has shown a wide range of applications in advertising, OLED display, printed electronics and other specialized utilities that require high-precision, mask-free, direct-writing deposition techniques. Nevertheless, the sedimentation risk of the refractory functional materials dispensed in inks hinders their further implementation. Herein, we present a bottom-up ink preparation strategy based on Cr2O3 by a one-step solvothermal method. The obtained ink remained stable under an equivalent natural sediment test for 2.5 years. The chemical composition of the solvothermal product was characterized, and the mechanism of the superior dispersion stability of Cr2O3 particles was analysed. These amorphous Cr2O3 particles were capped by ligands generated via low-temperature solvothermal reactions. Ethanol and acetylacetone covering the particle surfaces play an essential role in enhancing the solubility of Cr2O3 particles in the solvent forming the ultrastable colloidal ink. Moreover, this ink was successfully printed using a direct-write inkjet system JetLab®II on nylon fabrics, and the printed area of the fabrics shows a spectral correlation coefficient of 0.9043 to green leaves. Finally, we believe that the one-step bottom-up fabrication method of Cr2O3-based pigment inks may provide a general approach for preparing metal oxide-based pigment inks with long-term dispersion stability.
ABSTRACT
BACKGROUND: To further the exploration of the pathogenesis of mild cognitive impairment (MCI), we aimed to determine the appropriate dose for a rapidly established MCI rat model using D-galactose (D-gal), with lasting cognitive effects. METHODS: In Experiment 1, we evaluated various D-gal concentrations (100-2,000 mg/kg/day), and determined that, compared with saline injections of the same volume. In Experiment 2, we evaluated the duration of the effect of 1,000 mg/kg/day D-gal injections for 1 week, with MWM testing initiated at 1 day, 1 month, and 3 months after completion of the injection regime in three model groups, respectively. RESULTS: In Experiment 1, D-gal injections at a concentration of 1,000 mg/kg/day for 1 week was adequate to induce a significantly worse Morris water maze (MWM) test performance and pathomorphologic changes in the hippocampus, with MWM testing initiated 1 day after completion of the injection regime. In Experiment 2, Before modeling, the overall condition (fur, mental state, foraging behavior, and activity level), body weight, swimming speed, and swimming time did not significantly differ between the control (saline injections) and model groups (D-gal injections). After modeling, MWM test performance was considerably worse (longer escape latencies and fewer platform crossings within 90 seconds) in the model groups than in the control group, without significant differences among model groups. Furthermore, movement trajectories were similar among model groups. CONCLUSIONS: These results demonstrate that subcutaneous injections of D-gal 1,000 mg/kg/day for 1 week produce changes consistent with the characteristics and pathological processes of MCI. Thus, high-dose D-gal injection allows the rapid establishment of an MCI model that is effective and sustainable.
