LA-ICP-MS Trace-Element Analysis of Pyrite from the Huanxiangwa Gold Deposit, Xiong’ershan District, China: Implications for Ore Genesis

The Huanxiangwa deposit is a major gold deposit in the Xiong’ershan district, which is the third-largest gold-producing district in China. Pyrites from the Huanxiangwa deposit were investigated using ore microscopy and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Pyrite is the dominant Au-bearing mineral in the Huanxiangwa deposit and can be divided into two types: medium- to fine-grained subhedral-anhedral pyrite (Py1) disseminated in altered rocks and coarse-grained subhedral-euhedral pyrite (Py2) hosted in auriferous quartz veins. LA-ICP-MS time-resolved depth profiles show that invisible gold occurs primarily as solid solution or as homogeneously distributed nanoparticles of native gold, electrum, or Au-Ag-Te minerals in Py1, whereas it is present mainly as nano- to submicron-sized inclusions of complex Au-Ag-Cu-Pb-Zn domains in Py2. The presented data indicate that the Huanxiangwa deposit resulted from two episodes of hydrothermal mineralization associated with two distinct source reservoirs. The first episode of mineralization was linked to the dehydration of deep-seated mafic-ultramafic metamorphic rock during the Triassic collision of the North China Craton with the Yangtze Craton. The second episode of mineralization was related to hydrothermal activity resulting from Early Cretaceous I-type granitic magmatism

Wetting Behavior and Maximum Retention of Aqueous Surfactant Solutions on Tea Leaves

In this research, the maximum retention and wetting behavior of surfactant solutions (N-200, N-300, Tween-80, Morwet EFW, DTAB, SDS) on the surfaces of tea leaves was investigated based on surface free energy, surface tension, the contact angle, adhesion work, and adhesion force. The results showed that the contact angles of all surfactant solutions were kept constant with low adsorption at the tea leaf–liquid interfaces below 0.005%. With an increase in concentration, the contact angle of Tween-80 decreased sharply because the adsorption of molecules at the solid–liquid interfaces (ΓSL’) was several times greater than that at the liquid–air interfaces (ΓLV). Adhesion work decreased sharply and then reached a minimum at the critical micelle concentration (CMC), but then increased until reaching a constant. Moreover, a high adhesion force did not indicate better wettability, as it does with rose petals and peanut leaves. For tea leaf surfaces, an increase in the contact angle brought about an increase in the adhesion force. In addition, the maximum retention for Morwet EFW is at different concentrations compared to N-200, N-300, Tween-80, DTAB, and SDS, where the maximum retention of Morwet EFW on tea leaves was 6.05 mg/cm2 at 0.005%.According to the mechanisms of wetting behavior on plant surfaces, a recipe for pesticide formulation can be adjusted with better wettability to reduce loss, improve utilization efficiency, and alleviate adverse effects on the environment

Uptake and Distribution of Fenoxanil-Loaded Mesoporous Silica Nanoparticles in Rice Plants

Mesoporous silica nanoparticles (MSNs) can be used as carriers to deliver pesticides into plants, which is considered to be one method of improving the efficacy of pesticide usage in agricultural production. In the present work, MSNs with an average diameter of 258.1 nm were synthesized and loaded with Fenoxanil. The structure of the nanocarriers was observed by scanning electron microscopy. The loading content of Fenoxanil-loaded MSNs was investigated. After rice plants in a hydroponic system were treated with loaded MSNs, the concentrations of Fenoxanil in different samples were determined using high-performance liquid chromatography–tandem mass spectrometry. The results suggested that rice plants can absorb MSNs from water through their roots, and the dosage has almost no effect on the distribution of Fenoxanil in rice plants. The application of pesticide-loaded nanoparticles in a hydroponic system poses a low risk of Fenoxanil accumulation in rice

Hypoxia Inducible Factor-1α Attenuates Ischemic Brain Damage by Modulating Inflammatory Response and Glial Activity

Hypoxia-inducible factor 1 can sufficiently control the progress of neurological symptoms after ischemic stroke owing to their actions associated with its downstream genes. In this study, we evaluated the role of HIF-1α in attenuating brain damage after endothelin-1 injection. Focal cerebral ischemia in mice were induced by endothelin-1 microinjection. Hypoxia-inducible factor 1 activator, dimethyloxalylglycine (DMOG), and HIF-1α inhibitor, acriflavine (ACF), were used to evaluate the hypoxia-inducible factor 1 activity during cerebral ischemia. The expression levels of HIF-1α, glial fibrillary acidic protein (GFAP), interleukin-10 (IL-10), inducible nitric oxide synthase (iNOS), phosphorylated I-kappa-B-alpha/total I-kappa-B-alpha (p-IκBα/IκBα) and nuclear factor kappa B (NF-kB) were assessed. Besides, mRNA levels of IL-10, tumor necrosis factor- alpha (TNF-α), and NF-kB were also analyzed. Results showed a noticeable increase in hypoxia-inducible factor 1 and IL-10 levels in the DMOG group with a decline in iNOS, TNF-α, and NF-kB levels, implying the anti-inflammatory role of hypoxia-inducible factor 1 activator following stroke. These findings were further corroborated by GFAP immunostaining that showed astrocytic activation to be inhibited 12 days post-ischemia, as well as histological and TEM analyses that demonstrated hypoxia-inducible factor 1 induction to alleviate neuronal soma damage and cell death. Based on our study, HIF-1α could be a potential therapeutic target for ischemic stroke

Enhancing the Stability and Effectivity of Multiple Pesticide Formulation Mixtures by Adding an Eco-Friendly Adjuvant

In recent years, aviation spray has been developed rapidly in plant protection, and it is common to mix pesticide formulations or fertilizers before spraying. However, serious instability of the pesticide tank mixture usually occurs in the process, resulting in loss of effect, drug damage, and even huge environmental pollution. However, this has not been studied further by researchers. Here, we evaluated the stability of the pesticide tank mixture by particle size, ζ potential, multiple light scattering, etc., and screened out the surfactants sodium dodecyl sulfate (SDS), sodium lauryl polyoxyethylene ether sulfate (AES), and natural polymer xanthan gum (XG) to stabilize the system. The results indicate that SDS and AES stabilize the pesticide tank mixture relying on the increase in the electrostatic repulsion of colloidal particles; XG stabilizes the system due to the increase in the steric hindrance. The results of multiple light scattering show that all 2.0 wt % SDS, 2.0 wt % AES, and 0.05 wt % XG decrease the stability index (SI) of the pesticide tank mixture from 1.44 to less than 0.71, which significantly improves the stability. Overall, our results demonstrate the feasibility of using XG as a safer, more cost-effective, and sustainable alternative to commercial synthetic compatibility agents