[Spatio-temporal Evolution and Prediction of Carbon Storage in Huaibei City Based on InVEST-PLUS Model].

This study aimed to investigate the impact of spatiotemporal changes in land use on ecosystem carbon storage. The study analyzed the spatiotemporal changes in carbon storage in the study area based on land use data from five periods (1985, 1995, 2005, 2015, and 2020) using the InVEST model. The PLUS model was used to predict land use changes in the study area under four different scenarios (natural development, farmland protection, ecological protection, and double protection of farmland and ecology) in 2035, and the ecosystem carbon storage under different scenarios was estimated. The results of the study indicated that the farmland in the area under investigation had been decreasing consistently from 1985 to 2020, with a more rapid rate of change observed between 2015 and 2020. During this period, the overall dynamic attitude towards land use reached 34.62 %. Additionally, the carbon storage in the area showed a decreasing trend over the years, with a decrease of 1.55×105 t from 1985 to 2020. Between 2005 and 2015, the carbon storage showed a decrease of 1.22×105 t, with an average annual decrease of 1.22×104 t. The areas with higher carbon storage were located in the eastern part of the study area, whereas areas with lower carbon storage were found in the central and northwestern parts. Although the proportion of carbon storage in farmland decreased from 66.89 % to 57.73 %, farmland remained the most important carbon pool in the study area. The conversion of other land use types to grassland and forestland was advantageous for increasing ecosystem carbon storage. Finally, the study projected that by 2035, the carbon storage in the natural development scenario, the farmland protection scenario, the ecological protection scenario, and the dual protection scenario would be 81.77×105, 82.45×105, 82.82×105, and 82.51×105 t, respectively.

Supramolecular architectures of beta-cyclodextrin-modified chitosan and pyrene derivatives mediated by carbon nanotubes and their DNA condensation.

Beta-cyclodextrin-modified chitosan 1 was synthesized via the Schiff base reaction between 6-O-(4-formylphenyl)-beta-cyclodextrin and chitosan (CHIT), and then the supramolecular dyad assemblies 2 and 3 were respectively fabricated from the subunit 1 through the inclusion of adamantane-modified pyrene into the beta-cyclodextrin cavity and the wrapping of a CHIT chain on multiwalled carbon nanotubes (MWCNTs). The water-soluble dyad 3 further interacted with adamantane-modified pyrene, forming a stable triad assembly 4. They were extensively characterized by NMR, thermogravimetric analysis, UV-vis, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and atomic force microscopy (AFM). Furthermore, the DNA condensation abilities of 1-4 were validated by AFM and dynamic light scattering, which indicates that the DNA-condensing capability of CHIT can be pronouncedly improved by either the pyrene grafts or the MWCNT medium. The cooperation between cationic and aromatic groups as well as the dispersion of CHIT agglomerates by MWCNTs are the key factors to enhance DNA condensation of cationic polymers.

Solvent-controlled photoinduced electron transfer between porphyrin and carbon nanotubes.

beta-Cyclodextrin (beta-CD)-modified multiwalled carbon nanotubes (MWCNTs) were successfully prepared by reaction of surface-bound carboxylic chloride groups of MWCNTs with aminoethyleneamino-deoxy-beta-CD (ENCD) and comprehensively characterized by FTIR, Raman, and X-ray photoelectron spectroscopy and thermogravimetric and differential thermal analysis. The beta-CD-modified MWCNTs (ENCD-MWCNTs) are highly water-soluble, with a solubility of ca. 9.0 mg x mL(-1). Furthermore, the photoinduced electron transfer (PET) process between tetrakis(4-carboxyphenyl)porphyrin (TCPP) and ENCD-MWCNTs was investigated by means of fluorescence, fluorescence decay, transient absorption spectroscopy, and cyclic voltammetry. Obvious quenching processes were observed upon addition of both MWCNT-COOH and ENCD-MWCNTs to the aqueous solutions of TCPP, indicating that the PET process between TCPP and carbon nanotubes takes place upon irradiation. When 1-adamantane acetic acid was added to the aqueous solutions of TCPP/MWCNT-COOH and TCPP/ENCD-MWCNTs, respectively, the former fluorescence remains, while the latter fluorescence recovers. On the contrary, the fluorescence intensity of TCPP in the DMF solution was hardly decreased upon addition of ENCD-MWCNTs, whereas its fluorescence was quenched in the presence of MWCNT-COOH. The observations indicate that the CD cavities play a vital role on the control of the PET process.