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Climate change can affect wind erosion power and hence induce changes in wind erosion rates. In this study, the wind erosion climate factor (C-factor), proposed by the Food and Agriculture Organization of the United Nations, was used to assess the impact of changes in climate on wind erosion climatic erosivity. The Mann-Kendall test was employed to detect trends in the C-factor during the period of 1961–2017 in the farming-pastoral zone of northern China. Sensitivity analysis was used to determine the sensitivity of the C-factor to changes in key climate factors. Furthermore, a comparison of the contributions of different climate factors was carried out to understand their impact on changes in the C-factor. The results indicated that most of the surveyed region exhibited decreasing trends in wind speed at a confidence level of 90%, while maximum and minimum temperatures showed increasing trends throughout the study area. As a consequence of decreasing wind speed, the annual C-factor exhibited significant decreasing trends, with a mean slope of −0.58/yr. Seasonal analysis revealed that in most regions, the changes in the C-factor had significant decreasing trends in spring, winter, and autumn, while in more than two-thirds of the study area, no significant change trends in the C-factor were detected in summer at a confidence level of 90%. Sensitivity analysis showed that the C-factor was most sensitive to wind speed, and that the sensitivity coefficients from July to September were much higher than those in other months. Contribution analysis revealed that, for most stations, wind speed (with greater values of sensitivity coefficients) was the dominant factor in the change of C-factor, while for some stations, the minimum temperature made the most contribution to the C-factor's change due to its dramatic changes during the study period. Although the minimum temperature sensitivity coefficient was the lowest of all the sensitivity coefficients, it is urgent to evaluate the expected impact of minimum temperature due to its possible changes in the future. [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) is a major component of the global carbon cycle and has a potentially large impact on the greenhouse effect. Paddy soils are important agricultural soils worldwide, especially in Asia. Thus, a better understanding of the relationship between SOC of paddy soils and climate variables is crucial to a robust understanding of the potential effect of climate change on the global carbon cycle. A soil profile data set ( n = 1490) from the Second National Soil Survey of China conducted from 1979 to 1994 was used to explore the relationships of SOC density with mean annual temperature (MAT) and mean annual precipitation (MAP) in six soil regions and eight paddy soil subgroups. Results showed that SOC density of paddy soils was negatively correlated with MAT and positively correlated with MAP ( P < 0.01). The relationships of SOC density with MAT and MAP were weak and varied among the six soil regions and eight paddy soil subgroups. A preliminary assessment of the response of SOC in Chinese paddy soils to climate indicated that climate could lead to a 13% SOC loss from paddy soils. Compared to other soil regions, paddy soils in Northern China will potentially more sensitive to climate change over the next several decades. Paddy soils in Middle and Lower Yangtze River Basin could be a potential carbon sink. Reducing the climate impact on paddy soil SOC will mitigate the positive feedback loop between SOC release and global climate change. [ABSTRACT FROM AUTHOR]

Abstract: Though much attention has been paid to synthesis of cylindrical polymer brushes, it is still not easy to prepare well-defined brushes by a general approach. Herein, well-defined cylindrical polymer brushes with various side chains were synthesized via grafting-onto approach by CuAAC click chemistry. Narrowly dispersed polymer backbones functionalized with azide groups were obtained by post-modification of poly(glycidyl methacrylate) (PGMA) which was prepared by reversible addition-fragmentation chain transfer (RAFT) mediated radical polymerization. The alkyne-terminated side chains, polystyrene, polyacrylates, polymethacrylates and poly(N-alkyl acrylamide)s, were synthesized by RAFT mediated radical polymerization with alkyne-containing chain transfer agents (CTAs). The CuAAC reactions between the backbone and side chain polymers were conducted with an equivalent feed of alkyne-terminated side chains and azide groups under mild conditions. Influences of reaction conditions and chemical composition of polymer side chains on grafting efficiency and molecular weight distribution of the polymer brushes were investigated. It is demonstrated that the side chains of polystyrene, polyacrylates and poly(N-alkyl acylamide)s were grafted at a density above 85% while that of polymethacrylates decreased to ca. 50%. The polymer brushes synthesized under the optimized reaction conditions had well-defined chemical composition and narrow distribution of molecular weight, and their wormlike morphology was visualized by atomic force microscopy (AFM). [Copyright &y& Elsevier]

The dibromomaleimide derivative, N-(4-bromobutyl)-dibromomaleimide (dBMIB), is found to be a highly efficient coupling agent to dimerize thiol-terminated hydrophilic polymers by substituent reaction. When mono-thiol poly(ethylene oxide) (PEO45-SH) is mixed with dBMIB in an equivalent molar feed in water, a dimer of PEO45 with a maleimide unit located at the chain center, (PEO45)2MIB, is obtained quantitatively. The dBMIB is also used to dimerize thiol- terminated poly( N-(2-acryloyloxyethyl) pyrrolidone) and poly( N, N-dimethyl acrylamide). Moreover, the butylene bromide of (PEO45)2MIB is transferred into a butylene azide, which is allowed to react with alkynyl-terminated polystyrene to give a A2B miktoarm star polymer via a copper-catalyzed azide-alkyne cycloaddition coupling reaction. [ABSTRACT FROM AUTHOR]

Abstract: We reported that well-defined polymer brushes could be prepared efficiently via the grafting-onto approach and the polymer brushes grafted with poly(ethylene oxide) (PEO), poly(ε-caprolactone) (PCL) and mixed PEO/PCL have been obtained. Firstly, poly(glycidyl methacrylate)s, PG100 and PG940, were prepared by controlled radical polymerization and their epoxy groups were reacted with sodium azide to introduce azido groups quantitatively. Then the PG derivatives bearing azido groups, poly(3-azido-2-hydroxypropyl methacrylate)100 (PGA100), were reacted with the alkynyl terminated either PEO (ay-PEO113) or PCL (ay-PCL17) through copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction under mild temperature. At a molar feed ratio of ay-PEO113:azido unit = 1:1, the coupling reaction with ay-PEO113 proceeded nearly quantitatively. At the same feed, the conversion of grafting ay-PCL17 dropped to ca. 80%. Amphiphilic polymer brushes with randomly grafted PEO and PCL branches were also obtained by feeding the mixed ay-PEO and ay-PCL during CuAAC. By coupling ay-PEO113 onto a long backbone PGA940, wormlike PEO brushes with an average length of 140 nm were prepared as demonstrated by AFM. This molecular worm was further labeled with Rhodamine B and then was incubated with liver cancer cells HepG2. Preliminary results indicated that the wormlike brushes could be internalized by the cells easily, suggesting the potential application as advanced vehicles for delivery. [Copyright &y& Elsevier]

Abstract: The dibenzocyclooctyne end functionalized agent 1 was designed as atom transfer radical polymerization (ATRP) initiator. The ATRP was then explored on three types of monomers widely used in free radical polymerization: methyl methacrylate, styrene, and acrylates (n-butyl acrylate and tert-butyl acrylate). The living polymerization behaviors were obtained for the methyl methacrylate and styrene monomers. The SPAAC click reactivity of dibenzocyclooctyne end group were demonstrated by successfully reacting with azide functionalized small chemical agents and polymers. Various topological polymers such as block and brush polymers were produced from strain-promoted azide-alkyne cycloaddition reaction (SPAAC) using the resultant dibenzocyclooctyne end functionalized poly(methyl methacrylate)/polystyrene as building blocks. For the acrylates, however, the polymerization did not hold the living characteristics with the dibenzocyclooctyne end functionalized ATRP initiator 1. [Copyright &y& Elsevier]

The interactions of environmental compartments with epithelial cells are essential for mammary gland development and homeostasis. Currently, the direct crosstalk between the endothelial niche and mammary epithelial cells remains poorly understood. Here, we show that faciogenital dysplasia 5 (FGD5) is enriched in mammary basal cells (BCs) and mediates critical interactions between basal and endothelial cells (ECs) in the mammary gland. Conditional deletion of Fgd5 reduced, whereas conditional knockin of Fgd5 increased, the engraftment and expansion of BCs, regulating ductal morphogenesis in the mammary gland. Mechanistically, murine mammary BC-expressed FGD5 inhibited the transcriptional activity of activating transcription factor 3 (ATF3), leading to subsequent transcriptional activation and secretion of CXCL14. Furthermore, activation of CXCL14/CXCR4/ERK signaling in primary murine mammary stromal ECs enhanced the expression of HIF-1α-regulated hedgehog ligands, which initiated a positive feedback loop to promote the function of BCs. Collectively, these findings identify functionally important interactions between BCs and the endothelial niche that occur through the FGD5/CXCL14/hedgehog axis. [Display omitted] • Mammary FGD5 plays a critical role in maintaining mammary gland development • FGD5/ATF3/CXCL14 axis upregulates the proliferative activity of endothelial cells • HIF-1α in ECs promotes mammary organoid formation and reprogramming activity • FGD5/CXCL14/Hedgehog axis mediates crosstalk between basal cells and ECs Zhang et al. characterized a basal-to-endothelial signaling circuit that supports mammary development and differentiation. This research highlights the importance of mammary basal cell-expressed FGD5 in promoting EC proliferation, HIF-1α stabilization, and transcriptional activity, thereby governing mammary epithelial growth, metabolism, differentiation, and stem-like properties. [ABSTRACT FROM AUTHOR]

Abstract: A smart poly(ethylene oxide) polymer containing two thermally reversible groups located at the chain center (F2-PEO) was synthesized by a maleimide–furan (MF) [4+2] Diels–Alder (DA) reaction between one bis[(furan-2-yl)methyl] terephthalate (F2) and two maleimide-terminated poly(ethylene glycol) methyl ethers (MI-PEOs). MF adducts underwent retro-DA (rDA) addition at a higher temperature, and the maleimide–anthracene (MA) addition reaction could occur simultaneously. Therefore, when F2-PEO and bis((anthracen-10-yl)methyl) succinate (AN2) were refluxed in toluene for 48h, the cores of F2-PEOs were replaced with the MA adducts in situ to give new polymers AN2-PEOs. Moreover, when F2-PEOs were mixed with the molecules containing four anthracene units (AN4), the rDA reaction of the MF adducts and the MA addition reactions occurred simultaneously, generating four-arm star PEOs. The core reorganization of polymers has been confirmed by SEC, UV, 1H NMR, and MALDI-TOF mass spectra. [Copyright &y& Elsevier]

The immunoproteasome has emerged as a potential therapeutic target for idiopathic pulmonary fibrosis (IPF). We report herein our efforts to discover novel non-peptidic immunoproteasome inhibitors as potential treatment for IPF. A structure-based virtual screening was initially performed and the hit compound VS-7 with an IC 50 of 9.437 μM against β5i was identified. Hit evolution based on the interaction mode of VS-7 proceeded, and a potent β5i inhibitor 54 (IC 50 = 8.463 nM) with favorable subunit-selective profiles was obtained. Compound 54 also imposed significant effects on the release of TNF-α and IL-6, the transcriptional activity of NF-κB, as well as TGF-β1 induced fibroblast proliferation, activation and collagen synthesis. Notably, when administered at 30 mg/kg in a bleomycin-induced IPF mouse model, compound 54 showed anti-fibrotic effects comparable to the clinical drug nintedanib. The results suggest that selective inhibition of immunoproteasome could be an effective approach to treat IPF. [Display omitted] • A structure-based virtual screening identified the hit VS-7 as a β5i inhibitor. • A novel potent non-peptidic β5i inhibitor 54 was recognized by hit evolution. • 54 exhibited favorable subunit-selective profiles. • 54 showed significant anti-fibrotic effects both in vitro and in vivo. [ABSTRACT FROM AUTHOR]

Gully erosion is one of the major causes of land degradation in most areas and attracts increasing attention from researchers. We monitored gullies in the Kebai region in Heilongjiang Province of China by using remote sensing data and found that gully density increased with the increase in slope when the slope was less than 3°. Gully density in sunny slopes or windward slopes was greater than in shady slopes or leeward slopes because of the impacts of freezing and thawing, wind and solar radiation. Specifically, the gully density in northeast slope was the greatest and in southwest was the smallest. Gully density was reduced with increasing slope length and the longer the slope length, the less the gully density changed between 1965 and 2005. Affected by runoff, gullies most easily to occur in concave slopes and the critical elevation for gully erosion was 250-275 m. Moreover, hilly regions had the greatest gully density, followed by tableland regions, whereas the gully density in flatlands was the lowest. However, the gully density of these three types of landforms all increased between 1945 and 2000, and the portion of increase was 57.45% (hill), 52.91% (mesa) and 25.32% (plain), respectively. [ABSTRACT FROM AUTHOR]

Abstract: A Co-monosubstituted Keggin polyoxometalate with an antenna ligand linked to the Co(II) center with a Co(II)-containing cation has been prepared. The title compound, formulated as {Co(H2O)4(4,4′-bpy)}2(4,4′-Hbpy)2[SiW11Co(4,4′-bpy)O39]·5H2O (1) (4,4′-bpy=4,4′-bipyridine), was synthesized and characterized by elemental analysis, IR spectra, TG analysis, X-ray single crystal structure analysis and magnetic measurements. As far as we know, the title compound represents the first Co(II) substituted Keggin polyoxometalate with an antenna ligand structurally and magnetically characterized. [Copyright &y& Elsevier]