Regulation of SiO Nanoparticles on the Adsorptive Fractionation of Dissolved Organic Matter by Goethite.

SiO nanoparticles (SiONPs) are most widely available and coexisting with DOM at the mineral-water interface; however, the role of SiONPs in DOM fractionation and the underlying mechanisms have not been fully understood. Using Fourier transform ion cyclotron resonance mass spectrometry, combined with Fourier transform infrared spectroscopy and X-ray adsorption fine structure spectroscopy, was employed to investigate the adsorptive fractionation of litter layer-derived DOM on goethite coexisting with SiONPs under different pH conditions. Results indicated that the inhibitory effect of the coexisting SiONPs on OM sorbed by goethite was waning as environmental pH increased due to the reduced steric interactions and the concurrent elevated hydrogen bonding/hydrophobic partitioning interactions on the goethite surface.

Differential influences of forest floor-pyrolyzed biochar-derived and leached dissolved organic matter interaction with natural iron-bearing minerals in forest subsoil on the formation of mineral-associated soil organic matter.

The vertical sequestration of dissolved organic matter (DOM) by iron minerals along the soil profile is assumed to be central to the long-term storage of the soil organic matter (SOM) pool. However, there is limited information available about how the interaction between DOM and natural iron-bearing minerals shape mineral SOM associations quantitatively and qualitatively in forest subsoils. Here, we systematically investigated the influences of forest organic layer-pyrolyzed biochar-derived DOM (BDOM) and leached DOM (LDOM) on quantity, molecular composition, and diversity of deposition layer-derived iron minerals-associated OM by using Fourier transform ion cyclotron resonance mass spectrometry and other complementary spectroscopy.

Source, composition and molecular diversity of dissolved and particulate organic matter varied with riparian land use in tropical coastal headstreams.

Source, composition and molecular diversity determine the reactivity and stabilization of organic matter (OM, dissolved [DOM]/particulate [POM]), affecting its behavior and fate. Here, multiple spectral and mass spectrometry techniques were applied to examine how riparian land-use shaped the source, composition and molecular diversity of POM and DOM (HDOM) in adjacent headstreams. Compared to HDOM with abundant lignins, microbially-transformed heteroatoms and carboxyl-rich alicyclic acids (CRAMs), POM exhibited higher allochthonous characteristics and more bioactive components, but lower molecular weight and diversity in different land-use-dominated streams.

[Effect of Coconut Fiber Biochar and Its Nitrate Modification on Pb Passivation in Paddy Soils].

The effects of coconut fiber biochar (CFB) and nitrate-modified coconut fiber biochar (NCFB) on the passivation of exogenous lead (Pb) in paddy soils and their underlying mechanisms were investigated using soil incubation experiments combined with spectroscopic techniques such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), synchrotron radiation X-ray fluorescence (SRXRF), and Fourier transform infrared absorption spectroscopy (FTIR). The effects of NCFB and CFB on the passivation of exogenous lead (Pb) in paddy soils and its underlying mechanisms were investigated. Compared with that of CFB, the inner wall of NCFB honeycomb pores was rougher, and the amount of alcohol-phenol-ether functional groups containing the C-O structure and the amount of carboxyl groups containing the C[FY=,1]O/O[FY=,1]C-O structure on the surface of CFB was significantly decreased after nitric acid modification.

Molecular size-dependent compositions and lead (II) binding behaviors of two origins of organic fertilizers-derived dissolved organic matter.

The application of organic fertilizers caused large amounts of dissolved organic matter (DOM) entering the soil environment and influencing the behaviors and fates of heavy metals. Here, we investigated the molecular weight-dependent (high molecular weight [HMW], 1 kDa-0.7 µm; low molecular weight [LMW], <1 kDa) compositions and lead (Pb) binding behaviors of DOM derived from sheep manure-based (SMOF) and shrimp peptide-based organic fertilizers (SPOF) using chromophoric and fluorescent spectroscopy, Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and two-dimensional correlation spectroscopy (2D-COS).

Impacts of Cold-Stress Stimulation On Mice Pregnancy.

Background: Animals exposed to cold stress develop hypertension; however, the effects of cold-induced hypertension on pregnancy remain unclear. We therefore, aimed to investigate the impacts of cold-stress stimulation on mice pregnancy.

Methods: Four groups of mice were used in the study: non-pregnant control group (NN), non-pregnant cold-stress group (NC), pregnant control group (PN) and pregnant cold-stress group (PC).