Stoichiometry of base cations and silicon during weathering of a deep soil profile derived from granite

Evaluation of the stoichiometry of base cations(BCs,including K^(+),Na^(+),Ca^(2+),and Mg^(2+))and silicon(Si)(BCs:Si)during soil mineral weathering is essential to accurately quantify soil acidification rates.The aim of this study was to explore the differences and influencing factors of BCs:Si values of different soil genetic horizons in a deep soil profile derived from granite with different extents of mineral weathering.Soil type was typic acidi-udic Argosol.Soil samples were collected from Guangzhou,China,which is located in a subtropical region.To ensure that the BCs and Si originated from the mineral weathering process,soil exchangeable BCs were washed with an elution treatment.The BCs:Si values during weathering were obtained through a simulated acid rain leaching experiment using the batch method.Results showed that soil physical,chemical,and mineralogical properties varied from the surface horizon to saprolite in the soil profile.The BCs:Si values of soil genetic horizons during weathering were 0.3–3.7.The BCs:Si value was 1.7 in the surface horizon(A),1.1–3.7 in the argillic horizon(Bt),and 0.3–0.4 in the cambic(Bw)and transition(BC)horizons,as well as in horizon C(saprolite).The general pattern of BCs:Si values in the different horizons was as follows:Bt>A>Bw,BC,and C.Although BCs:Si values were influenced by weathering intensity,they did not correlate with the chemical index of alteration(CIA).The release amounts of Si and BCs are the joined impact of soil mineral composition and physical and chemical properties.A comprehensive analysis showed that the BCs:Si values of the soil derived from granite in this study were a combined result of the following factors:soil clay,feldspar,kaolinite,organic matter,pH,and CIA.The main controlling factors of BCs:Si in soils of different parent material types require extensive research.The wide variance of BCs:Si values in the deep soil profile indicated that H+consumed by soil mineral weathering was very dissimilar in the soils with different weathering intensities derived from the same parent material.Therefore,the estimation of the soil acidification rate based on H+biogeochemistry should consider the specific BCs:Si value.

Research on Moflo XDP high speed cell sorting techniques and parameter optimization

This article aims to discuss strategies to operate Moflo XDP high-speed sorting equipment for cell sorting and optimize the instrument to run in the best operating state.Using fluorescent microspheres to quickly calibrate the position of the main liquid flow and the laser beam,adjust the amplitude and frequency according to different size CytoNozzles to find the best breakoff point,and adjust the four-way side flow to achieve the stable maintaining of the equipment,so as to quickly sort sample at high-speed.The absence of air bubbles in the sheath liquid barrel and the liquid path is the key to achieving a stable sorting-maintaining in the sorting process.The accurate calculation of the breakoff point and drop delay is the key to improve sorting efficiency and cell activity.