Selective Acceptorless Dehydrogenation of Primary Amines to Imines by Core-Shell Cobalt Nanoparticles

Core–shell nanocatalysts are attractive due to their versatility and stability. Here, we describe cobalt nanoparticles encapsulated within graphitic shells prepared via the pyrolysis of a cationic poly-ionic liquid (PIL) with a cobalt(II) chloride anion. The resulting material has a core–shell structure that displays excellent activity and selectivity in the self-dehydrogenation and hetero-dehydrogenation of primary amines to their corresponding imines. Furthermore, the catalyst exhibits excellent activity in the synthesis of secondary imines from substrates with various reducible functional groups (C=C, C≡C and C≡N) and amino acid derivatives. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA

Comparative study of nitrogenase activity in different types of biological soil crusts in the Gurbantunggut Desert, Northwestern China

Biological soil crusts cover large areas of the Gurbantunggut Desert in northwestern China where they make a significant contribution to soil stability and fertility. The aim of this study was to quantify the potential nitrogen-fixing activity (NA) of different types of biological soil crusts in the Gurbantunggut Desert. The results suggest that NA (nmol C2H4 m(-2) h(-1)) for each type of crusts was highly variable. Seasonal variation was also important, with all three types of crusts responding in a similar way to changes in environmental conditions. From March to May, NA was relatively low for all crust types. During this season, NA was 2.26 x 10(3) for cyanobacterial crust followed by lichen crust (6.54 x 10(2)) and moss crust (6.38 x 10(2)). From June to October, all crust types reached their highest level of NA, especially lichen crust and moss crust (p < 0.01). The NA of cyanobacterial crust (9.81 x 10(3)) was higher than that of lichen crust (9.06 x 10(3)) and moss crust (2.03 x 10(3)). From November to February, when temperatures were consistently low (<0 degrees C), NA was at its lowest level, especially in cyanobacterial crust (4.18 x 10(2)) and moss crust (5.43 x 10(2)) (P < 0.01). Our results indicate that species composition is critical when estimating N inputs in desert ecosystems. fit addition, all three types of crusts generally responded in a similar way to environmental conditions. The presence of N fixation activity in all crusts may contribute to the maintenance of fertility in sparsely vegetated areas and provide surrounding vascular plant with fixed nitrogen. (C) 2009 Elsevier Ltd. All rights reserved

The variation of morphological features and mineralogical components of biological soil crusts in the Gurbantunggut Desert of Northwestern China

Increasingly complex life forms were found in older biological soil crusts in the Gurbantaunggut Desert in Northwestern China. These crusts may play a critical role in mineral erosion and desert soil formation by modifying the weathering environment and ultimately affecting mineralogical variance. To test this hypothesis, variations in the morphological features and mineralogical components of successional biological soil crusts at 1 cm were studied by optical microscopy, SEM and grain size analysis. Concentrations of erosion-resistant minerals decreased with crust succession, while minerals susceptible to weathering increased with crust development. Neogenetic minerals were found in late stage crusts, but not in early stage crusts. Silt and clay concentrations were highest in early formation crusts and soil mean particle size decreased with crust succession. Cyanobacteria, lichen and moss were shown to erode and etch rocks, and secondary minerals produced by weathering were localized with the living organisms. Thus, more developed crusts appeared to contribute to greater mineral weathering and may be a major cause of mineralogical variance seen in the Gurbantunggut Desert. The greater activity and complexity of older crusts, as well as their improved moisture condition may function to accelerate mineral weathering. Therefore, protection and recovery of biological crusts is vital for desert soil formation

The Role of Nonphotosynthetic Microbes in the Recovery of Biological Soil Crusts in the Gurbantunggut Desert, Northwestern China

The mechanisms regulating the recovery of biological soil crusts (BSCs) due to the presence of nonphotosynthetic microbes were investigated using a soil scalping technique. Microscopic examinations identified the oglueo and oropeo action of bacteria and fungi at the initial stages of recovery of BSCs prior to the appearance of cyanobacteria. Extracellular polymeric substances (EPS) excreted by bacteria principally contained glucose and mannose. The optimum conditions for EPS production included the availability of glucose as the carbon source, the presence of CaCO3 (2g/L), KH2PO4 (0.3g/L), and MgSO4 (0.1g/L), a pH of 7 and incubation at 37 degrees C for 72h. Crust-forming tests in the laboratory and in the field demonstrated that inoculation of bare sand with oligotrophic bacteria was effective in accelerating the recovery of BSCs. The number of nonphotosynthetic microbes (especially actinomycetes and fungi) recorded in both the crust layer (0-2cm) and subsurface layer (2-5cm) was higher after 3 years than after 1 year. Microbial spatial variability of BSCs was related to nutrient status, especially available N

Microalgal species variation at different successional stages in biological soil crusts of the Gurbantunggut Desert, Northwestern China

Biological soil crusts (BSC), most notably lichen crusts, develop and diversify in the Gurbantunggut Desert, the largest fixed and semi-fixed desert in China. Four different successional stages of BSC, including bare sand, microalgal crusts, lichen crusts, and moss crusts, were selected to determine successional changes in microalgal species composition and biomass and formation of BSC. A 10 x 10-m observation plot was established in an interdune region of the Gurbantunggut Desert and data were collected over an 8-year study period. The main results were: (1) different successional stages of BSC significantly affected the content of soil organic C and total and available N but not the total and available P and K content of soil; (2) composition of microalgal communities differed among the four successional stages; (3) significant differences in microalgal biomass were observed among the four successional stages; (4) bare sand was mainly uncompacted sand gains; (5) filamentous cyanobacteria, particularly Microcoleus vaginatus, were the dominant species in the early phase of crust succession. The presence of fungal mycelium and moss rhizoids prevented water and wind erosion

Serum CA72-4 is specifically elevated in gout patients and predicts flares

Objectives Serum CA72-4 levels are elevated in some gout patients but this has not been comprehensively described. The present study profiled serum CA72-4 expression in gout patients and verified the hypothesis that CA72-4 is a predictor of future flares in a prospective gout cohort. Methods To profile CA72-4 expression, a cross-sectional study was conducted in subjects with gouty arthritis, asymptomatic hyperuricaemia, four major arthritis types (OA, RA, SpA, septic arthritis) and healthy controls. A prospective gout cohort study was initiated to test the value of CA72-4 for predicting gout flares. During a 6-month follow-up, gout flares, CA72-4 levels and other gout-related clinical variables were observed at 1, 3 and 6 months. Results CA72-4 was highly expressed in patients with gouty arthritis [median (interquartile range) 4.55 (1.56, 32.64) U/ml] compared with hyperuricaemia patients [1.47 (0.87, 3.29) U/ml], healthy subjects [1.59 (0.99, 3.39) U/ml] and other arthritis patients [septic arthritis, 1.38 (0.99, 2.66) U/ml; RA, 1.58 (0.95, 3.37) U/ml; SpA, 1.56 (0.98, 2.85) U/ml; OA, 1.54 (0.94, 3.34) U/ml; P 6.9 U/ml) was the strongest predictor of gout flares (hazard ratio = 3.889). Prophylactic colchicine was effective, especially for patients with high CA72-4 levels (P = 0.014). Conclusion CA72-4 levels were upregulated in gout patients who experienced frequent flares and CA72-4 was a useful biomarker to predict future flares