Autotrophic ammonium nitrogen removal process mediated by manganese oxides: Bioreactors performance optimization and potential mechanisms.

Manganese(IV) (Mn(IV)) reduction coupled with ammonium (NH-N) oxidation (Mnammox) has been found to play a significant role in the nitrogen (N) cycle within natural ecosystems. However, research and application of the autotrophic NH-N removal process mediated by manganese oxides (MnOx) in wastewater treatment are currently limited. This study established autotrophic NH-N removal sludge reactors mediated by various MnOx types, including δ-MnO (δ-MSR), β-MnO (β-MSR), α-MnO (α-MSR), and natural Mn ore (MOSR), investigating their NH-N removal performances and mechanisms under different initial N loading and pH conditions.

Spectral and molecular insights into the variations of dissolved organic matter in shallow groundwater impacted by surface water recharge.

Dissolved organic matter (DOM) represents one of the most active elements in aquatic systems, whose fraction is engaged in chemical and biological reactions. However, fluorescence, molecular diversity and variations of DOM in groundwater systems with the alteration of surface water recharge remain unclear. Herein, Excitation-emission matrix (EEM) fluorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) combined with principal component coefficients, parallel factor analyses (PARAFAC) with two‒dimensional correlation spectroscopy (2D-COS) were applied in this study.

Metabolomic and metagenomic analyses elucidate the role of intercropping in mitigating continuous cropping challenges in tobacco.

Introduction: Crop rotation of tobacco with other crops could effectively break the negative impact of continuous tobacco cropping, but the mechanisms of intercropping system effects on tobacco, especially on the rhizosphere, are not clear.

Methods: In this study, we investigated the impact of intercropping system on the diversity and function of tobacco metabolites and microorganisms through metabolomic and metagenomic analyses of the tobacco rhizosphere microenvironment intercropped with maize and soybean.

Results: The results showed that the contents of huperzine b, chlorobenzene, and P-chlorophenylalanine in tobacco rhizosphere soils differed significantly among soybean-tobacco and maize-tobacco intercropping system.

Whole-genome sequencing identifies novel loci for keratoconus and facilitates risk stratification in a Han Chinese population.

Background: Keratoconus (KC) is a prevalent corneal condition with a modest genetic basis. Recent studies have reported significant genetic associations in multi-ethnic cohorts. However, the situation in the Chinese population remains unknown.