Sensitive Determination of Arsenic by Photochemical Vapor Generation with Inductively Coupled Plasma Mass Spectrometry: Synergistic Effect from Antimony and Cadmium.

A novel method for the determination of trace arsenic (As) by photochemical vapor generation (PVG) with inductively coupled plasma mass spectrometry measurement was developed in this study. The synergistic effect from antimony (Sb) and cadmium (Cd) was found for the photochemical reduction of As for the first time. Effective photochemical reduction of As was obtained in the system containing 10% (v/v) acetic acid, 5.0 mg L-1 Sb(III), and 20.0 mg L-1 Cd(II) with 100 s UV irradiation. Analytical sensitivity of As(III) was comparable with that of As(V) under the tested conditions, making direct determination of total As feasible. Compared to the pneumatic nebulization method, analytical sensitivity of the developed method was enhanced about 50 folds. The PVG efficiency was estimated up to be 99 ± 3%. The limit of detection (LOD) (3σ) was found to be 2.1 ng L-1 for As, which was improved about 30-fold compared to that using direct sample introduction solution nebulization. Considering the sample dilution prior to analysis (usually one-fold), the LOD was actually enhanced about 15 folds. The relative standard deviations of seven replicate measurements of 1.0 µg L-1 As(III) and As (V) standard solutions were 2.3 and 2.9% for As(III) and As(V), respectively. The proposed method was successfully applied for the detection of As in certified reference materials of sediments (GBW07303a and GBW07305a), as well as three water samples. The mechanism of the PVG system was investigated by using gas chromatography mass spectrometry, electron paramagnetic resonance, and X-ray photoelectron spectroscopy. (CH3)3As along with (CH3)3Sb were synthesized under UV irradiation. Besides, volatile species of Cd were also found. The result obtained in this study is useful for developing efficient "sensitizers" in PVG and understanding the transformation of As in the presence of hydride/cold vapor forming elements in the photochemical process.

Multimodal Fusion Network for 3-D Lane Detection.

3-D lane detection is a challenging task due to the diversity of lanes, occlusion, dazzle light, and so on. Traditional methods usually use highly specialized handcrafted features and carefully designed postprocessing to detect them. However, these methods are based on strong assumptions and single modal so that they are easily scalable and have poor performance. In this article, a multimodal fusion network (MFNet) is proposed through using multihead nonlocal attention and feature pyramid for 3-D lane detection. It includes three parts: multihead deformable transformation (MDT) module, multidirectional attention feature pyramid fusion (MA-FPF) module, and top-view lane prediction (TLP) ones. First, MDT is presented to learn and mine multimodal features from RGB images, depth maps, and point cloud data (PCD) for achieving optimal lane feature extraction. Then, MA-FPF is designed to fuse multiscale features for presenting the vanish of lane features as the network deepens. Finally, TLP is developed to estimate 3-D lanes and predict their position. Experimental results on the 3-D lane synthetic and ONCE-3DLanes datasets demonstrate that the performance of the proposed MFNet outperforms the state-of-the-art methods in both qualitative and quantitative analyses and visual comparisons.

Detection of trace antimony by vanadium (IV) ion assisted photochemical vapor generation with inductively coupled plasma mass spectrometry measurement.

In this work, a method for sensitive detection of trace antimony (Sb) was developed by inductively coupled plasma mass spectrometry (ICP MS) coupled with photochemical vapor generation (PVG). V(IV) ions were used as new "sensitizers" for improving the PVG efficiency of Sb. Factors influenced the PVG and the detection of Sb by ICP MS were investigated, including the type and concentration of low molecular weight organic acids, the UV irradiation time, the concentration of V(IV) ions, the air-liquid interface, the flow rate of Ar carrier gas, and interferences from co-existing ions. It was found that efficient reduction of Sb was obtained in the medium of 10% (v/v) formic acid (FA), 10% (v/v) acetic acid (AA), and 80 mg L-1 of V(IV) with 100 s UV irradiation. Under the selected conditions, there was no significant difference in analytical sensitivity between Sb(III) and Sb(V). The limit of detection (LOD, 3σ) was 4.7 ng L-1 for Sb with ICP MS measurement. Compared to traditional direct solution nebulization, the analytical sensitivity obtained in this work was enhanced about 19-fold. Relative standard deviations (RSDs, n = 7) were 1.9% and 2.3% for replicate measurement of 0.5 µg L-1 Sb(III) and Sb(V) standard solutions, respectively. The proposed method was applied for the determination of trace Sb in water samples and two certified reference materials (CRMs) of sediments with satisfactory results. Moreover, the generated volatile species of Sb in this work was found to be (CH3)3Sb.

miR-1184 regulates inflammatory responses and cell apoptosis by targeting TRADD in an LPS-induced cell model of sepsis.

MicroRNAs (miRs) have been reported to be potential clinical biomarkers for sepsis. miR-1184 is a multifunctional microRNA that exerts roles in the development of various diseases. However, the role of miR-1184 in children with sepsis remain unknown. In the present study, THP-1 cells were stimulated with 1 µg/ml lipopolysaccharide (LPS) for 24 h to establish an in vitro sepsis model. Reverse transcription-quantitative PCR was used to evaluate the expression of miR-1184 in clinical specimens, and of IL-6, TNF-α, IL-1ß, miR-1184 and TNF receptor type 1-associated DEATH domain protein (TRADD) in cells with and without LPS treatment. Cell apoptosis was assessed using flow cytometry. Binding between miR-1184 and TRADD was predicted using bioinformatics software, and a luciferase reporter assay was performed to verify the interaction between miR-1184 and TRADD in LPS-induced THP-1 cells. In addition, western blot analysis was performed to detect TRADD and proteins associated with the NF-κB pathway. The results showed that miR-1184 was downregulated in the blood of children with sepsis and LPS-induced THP-1 cells. Overexpression of miR-1184 alleviated the LPS-induced production of inflammatory cytokines and cell apoptosis. Moreover, TRADD was verified to be a direct target of miR-1184. Upregulation of TRADD reversed the effects of miR-1184 on the LPS-induced inflammatory response and apoptosis of THP-1 cells. Furthermore, the NF-κB pathway was shown to be associated with the regulatory role of miR-1184 in sepsis. The present study provides evidence that miR-1184 exerts inhibitory effects on inflammatory responses and apoptosis in sepsis by targeting TRADD, which suggests that miR-1184 may be a novel potential target for the therapy of children with sepsis.

Tightness Mechanism and Quantitative Analysis of the Pore Evolution Process of Triassic Ch-6 Tight Reservoir, Western Jiyuan Area, Ordos Basin, China.

Exploring the tightness mechanism through a quantitative analysis of the pore evolution process is the research hotspot of tight oil reservoirs. The physical characteristics of Chang 6 (Ch-6) sandstones in the western Jiyuan area have the typical features of a tight oil reservoir. Based on the reservoir physical property, lithological characteristics, diagenetic types and sequence, and burial and thermal evolution history, this study analyzes the factors leading to reservoir tightness and establishes the model of the pore evolution process. The results show that the sedimentary microfacies type controls the reservoir detrital material and further affects its physical properties. The high content of feldspar and rock fragments and the fine grain size are the material cause for the reservoir tightness. The sandstones of the main underwater distributary channel are the dominant sedimentary bodies for the development of a high-quality reservoir. In terms of diagenesis, compaction is the primary cause for reservoir tightness, and the porosity reduction by cementation is weaker than that by compaction. Meanwhile, the quantitative calculation results indicate that the porosity losses by compaction, carbonate cementation, kaolinite cementation, chlorite coatings, and siliceous cementation are 23.5, 3.1, 3.8, 3.0, and 0.8%, respectively. In addition, dissolution is significant to improve the reservoir physical property, and the increase of dissolved porosity is around 3.2%. More significantly, this study uses a detailed and systematic method for analyzing the tightness mechanism and the pore evolution process of the Ch-6 sandstones in the western Jiyuan area, Ordos Basin, China.