The structures of histidine intercalated hydrotalcite–montmorillonite complex (His–LDHs–MMT) were studied using the DMol3 code, GGA/PW91 function, and DND basis set of the density functional theory (DFT). The geometries of His–LDHs–MMT were optimized, and their electronic properties were calculated. The results showed that the structure of the complex can be seen as that the quaternary ammonium group of histidine was adsorbed on the oxygen of MMT lamella, and its oxygen on the carboxylic acid anion was combined with the hydrogen atoms of the LDHs lamella. It was determined that the interaction mainly consisted in hydrogen bonding and electrostatic force. The average binding energies per histidine of His–LDHs and His–MMT were about −65.89 and −78.44 kcal/mol, respectively. The density of states of the complexes showed that the 2p orbitals of oxygen were dominant, and the 1s orbit of hydrogen near the Fermi level indicate the formation of hydrogen bonds in the complex. The charge density data displayed the density field of histidine carboxylic acid anion overlapped with that of hydrotalcite layer, indicating that a strong hydrogen bond interaction existed between histidine and hydrotalcite layer. The analysis of the electrostatic potential of complex indicated that the electrostatic interaction between histidine and MMT is obviously stronger than that of LDHs. The simulated XRD spectra showed the special diffraction peaks of LDHs and MMT layer in the complex.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Climate change and anthropogenic activities are accelerating environmental changes, challenging wild animals' survival. Behavioral plasticity, such as adjusting habitat selection and foraging activity, is a key mechanism for responding to rapid environmental changes in the Anthropocene era. However, this shift may expose animals to new challenges. Moreover, not all behavioral plasticity is adaptive, as evidenced by ecological traps. This study focuses on Poyang Lake, a Ramsar wetland and a critical wintering ground for waterbirds in the East Asian-Australasian Flyway. Historically, the migratory patterns of waterbirds were synchronized with the plant life cycle. However, recent hydrological regime changes have diminished suitable habitats and food resources, thereby posing significant conservation challenges for waterbirds. Utilizing multiyear satellite tracking data, we examined the variations in wintering home range and behaviors of four herbivorous waterbird species between natural and artificial wetlands in Poyang Lake under different hydrological conditions. Our results reveal significant differences in home range area and movement speed among species and across hydrological years. All species demonstrated a marked increase in their use of artificial wetlands under unfavorable conditions. Specifically, the Greater White-fronted Goose (Anser albifrons) shifted its distribution to artificial wetlands during drought years while favoring natural wetlands under normal conditions, indicating a stress-induced adaptation. In contrast, the Bean Goose (A. fabalis) and Swan Goose (A. cygnoid) displayed greater behavioral plasticity. Notably, the Siberian Crane (Leucogeranus leucogeranus) increasingly used artificial wetlands, likely due to human protection, raising concerns about potential ecological traps. Additionally, waterbirds foraging in artificial wetlands generally exhibited higher movement speeds during drought conditions. This behavior suggests maladaptation and a more dispersed distribution. Our study underscored the critical role of artificial wetlands in supporting migratory waterbirds during drought, though elevated movement speeds observed in these habitats suggest potential maladaptation. Species-specific responses raise concerns about ecological traps if these habitats fail to meet key ecological needs. To ensure long-term conservation, efforts should focus on preserving natural wetlands and enhancing the quality of artificial habitats. Future research should prioritize long-term monitoring to guide habitat management and address species-specific needs in the face of climate change and habitat degradation.
In Poyang Lake, the largest and one of most important wintering sites in the East Asian-Australasian Flyway, Carex (Carex cinerascens Kük) meadows provide the primary food source for the wintering geese. However, Due to intensified river regulation and more frequent extreme climatic events such as drought, observational evidence suggests that the synchrony of geese migration and Carex phenology could not be maintained without human interventions, imposing a great risk of food shortage during the wintering period. Consequently, the current conservation priority in this Ramsar site is shifted to wet meadow improvement to ensure the optimal food quality. Understanding the food preferences of wintering geese is the key for effective wet meadow management. As the growth stage and nutrient level of food plants are the decisive factors influencing the diet selection of herbivores, in this study, we sampled the preferred food items by tracking the foraging paths of the Greater White-fronted Goose (n=84) and Bean Goose (n=34) to quantify the "foraging window" in terms of plant height,protein level, and energy content. Further, we established relationships between the above three variables of Carex based on in-situ measurements. The results show that the geese prefer plants with height rangeing from 2.4 to 25.0 cm, with protein content from 13.90 to 25.16%, and energy content from 1440.03 to 1813.63 KJ/100 g. While plant energy content increases with height, the height-protein level relationship is negative. The opposite growth curves signify a conservation challenge to maintain the delicate balance between the quantity and quality requirement of wintering geese. Carex meadow management, such as mowing, should focus on optimizing the timing of action to maximize energy supply while maintain the right protein level for the long-term fitness, reproduction and survival of the birds.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Here we report the use of 2-nitrobenzyl alcohol (NB) as a photoreactive group with amine selectivity and explore its applications for photoaffinity labeling and crosslinking of biomolecules. This work confirms that NB is an efficient photoreactive group and has great potential in drug discovery, chemical biology and protein engineering.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Lanthanide doping is widely employed to tune structural change temperature and electrical properties in ABO3-type perovskite ferroelectric materials. However, the reason that A-site lanthanide doping leads to the decrease of the Curie temperature is still not clear. Based on the reported Curie temperature of lanthanides (Ln) doped in two classic ferroelectrics PbTiO3 and BaTiO3 with A2+B4+O3-type perovskite structure, we discussed the relationship between the decrease rate of Curie temperature (ΔTC) and the bond strength variance of A-site cation (σ). For Nd ion doped Pb(Mg1/3Nb2/3)O3-PbTiO3 (Nd-PMNT) ferroelectric crystal as an example, the internal factors of the dramatic decline of the Curie temperature induced by A-site Nd doping were investigated under a systematic study. The strong covalent bonds of Ln-O play an important role in A-site Ln composition-induced structural change from ferroelectric to paraelectric phase, and it is responsible for the significant decrease in the Curie temperature. It is proposed that the cells become cubic around the Ln ions due to the strong covalent energy of Ln-O bonding in A-site Ln doped A2+B4+O3 perovskite ferroelectrics.
Continuous advancement in nonvolatile and morphotropic beyond-Moore electronic devices requires integration of ferroelectric and semiconductor materials. The emergence of hafnium oxide (HfO2)-based ferroelectrics that are compatible with atomic-layer deposition has opened interesting and promising avenues of research. However, the origins of ferroelectricity and pathways to controlling it in HfO2 are still mysterious. We demonstrate that local helium (He) implantation can activate ferroelectricity in these materials. The possible competing mechanisms, including He ion-induced molar volume changes, vacancy redistribution, vacancy generation, and activation of vacancy mobility, are analyzed. These findings both reveal the origins of ferroelectricity in this system and open pathways for nanoengineered binary ferroelectrics.
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