Current air quality models usually underestimate the concentration of ambient air sulfate, but the cause of this underestimation remains unclear. One reason for the underestimation is that the ...sulfate formation mechanism in the models is incomplete, and does not adequately consider the impact of the synergistic effects of high concentrations of multiple pollutants on sulfate formation. In this work, the roles of gaseous NO2, NH3 and solution ionic strength in the formation of sulfate in the aqueous phase were quantitatively investigated using a glass reactor and a 30 m3 smog chamber, separately. The results showed that sulfate formation was enhanced to different degrees in the presence of gas-phase NO2, NH3 and their coexistence as solutes in both liquid solution and aerosol water. NH3 enhances the aqueous oxidation of SO2 by NO2 mainly by accelerating the uptake of SO2 through increased solubility. More importantly, we found that high ionic strength in aerosol water could significantly accelerate the aqueous oxidation of SO2, resulting in unexpectedly high S(VI) formation rates. We estimate that under severe haze conditions, heterogeneous oxidation of SO2 by NO2 on aerosols may be much shorter than that through gas phase oxidation by OH, aided by high ionic strengths in aerosols. Considering the existence of complex air pollution conditions with high concentrations of NO2, NH3 and aerosol water, as expected in typical urban and suburban settings, the sulfate formation mechanisms revealed in the present work should be incorporated into air quality models to improve the prediction of sulfate concentrations.
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•Aqueous SO42− formation could be greatly enhanced with the presence of NO2 and NH3.•Higher reaction rate constants were observed duo to the higher ionic strengths.•Relationship between reaction rate constant and ionic strengths was obtained.
Much higher reaction rate constants (k) between NO2 and SO2 were observed in aerosol water compared to bulk waterdue to higher ionic strengths (I); Relationship between k and I was obtained.
An herbal prescription is usually composed of several herbal medicines. The complex and diverse components bring great challenges to its bioactivity study. To comprehensively analyze the bioactivity ...of an herbal prescription, a new strategy based on peak‐by‐peak cutting and knock‐out chromatography was proposed. In this strategy, active compounds were screened out via peak‐by‐peak cutting from an herbal extract, and the influence of a compound on the overall activity of the herbal extract was evaluated by knock‐out chromatography. Qiliqiangxin capsule is an herbal prescription composed of 11 herbal medicines for the treatment of chronic heart failure. A total of 71 peaks were collected through peak‐by‐peak cutting, and each peak was identified by a high‐resolution mass spectrum. The bioassay against 1,1‐diphenyl‐2‐picrylhydrazyl showed that two types of compounds namely salvianolic acids and caffeoylquinic acids were potent scavengers. Knock‐out chromatography suggested that the removal of one single compound had no obvious influence on the overall activity of the Qiliqiangxin capsule. After all the main peaks in the Qiliqiangxin capsule were knocked out, the remaining part still exhibited a potent activity, indicating high activity stability of the Qiliqiangxin capsule. The proposed strategy is helpful for the comprehensive analysis of the bioactivity of other herbal prescriptions.
Inflammation is a self-defense response to protect individuals from infection and tissue damage, but excessive or persistent inflammation can have adverse effects on cell survival. Many individuals ...become especially susceptible to chronic-inflammation-induced sensorineural hearing loss as they age, but the intrinsic molecular mechanism behind aging individuals' increased risk of hearing loss remains unclear. FoxG1 (forkhead box transcription factor G1) is a key transcription factor that plays important roles in hair cell survival through the regulation of mitochondrial function, but how the function of FoxG1 changes during aging and under inflammatory conditions is unknown. In this study, we first found that FoxG1 expression and autophagy both increased gradually in the low concentration lipopolysaccharide (LPS)-induced inflammation model, while after high concentration of LPS treatment both FoxG1 expression and autophagy levels decreased as the concentration of LPS increased. We then used siRNA to downregulate Foxg1 expression in hair cell-like OC-1 cells and found that cell death and apoptosis were significantly increased after LPS injury. Furthermore, we used d-galactose (D-gal) to create an aging model with hair cell-like OC-1 cells and cochlear explant cultures in vitro and found that the expression of Foxg1 and the level of autophagy were both decreased after D-gal and LPS co-treatment. Lastly, we knocked down the expression of Foxg1 under aged inflammation conditions and found increased numbers of dead and apoptotic cells. Together these results suggest that FoxG1 affects the sensitivity of mimetic aging hair cells to inflammation by regulating autophagy pathways.
The 17 spent fluid catalytic cracking refinery catalysts (SFCCCs) from different petroleum refineries were collected and the leachates of SFCCCs were prepared. The ecotoxicity of SFCCC leachates to ...Raphidocelis subcapitata was assayed. The results showed that the toxicity of the 17 SFCCCs differ greatly. Ji SFCCC was the most toxic to R. subcapitata with a 96 h EC50 value of 1.38%, while Ha SFCCC was the least toxic, with the EC50 value was >100%. The relationships between the toxicity of SFCCCs and the metal concentrations in leachates were analyzed. The concentration of Ni (p = 0.001), La (p = 0.001), Mn (p = 0.014), Ce (p = 0.017), Co (p = 0.018), and Ca (p = 0.031) in leachates showed significant correlation with EC50 values. The predictive model for the ecotoxicity of SFCCCs were established with the concentrations of Ni and La in leachates as:
ln(EC50) = 0.817 + exp(1.356 – 1.736 × CNi - 0.262 × CLa) (R2 = 0.926).
The main toxic ingredients of SFCCC to microalgae were identified for the first time in this work. The results and predictive model of this study are significance for toxicity determination and management of SFCCCs.
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•Toxicity of spent fluid catalytic cracking refinery catalysts was first evaluated.•Nickel and Lanthanum showed significant correlation with toxicity.•Models for the prediction of ecotoxicity of SFCCCs were established.
Dental follicles are necessary for tooth eruption, surround the enamel organ and dental papilla, and regulate both the formation and resorption of alveolar bone. Dental follicle progenitor cells ...(DFPCs), which are stem cells found in dental follicles, differentiate into different kinds of cells that are necessary for tooth formation and eruption. Runt-related transcription factor 2 (Runx2) is a transcription factor that is essential for osteoblasts and osteoclasts differentiation, as well as bone remodeling. Mutation of Runx2 causing cleidocranial dysplasia negatively affects osteogenesis and the osteoclastic ability of dental follicles, resulting in tooth eruption difficulties. Among a variety of cells and molecules, Nel-like molecule type 1 (Nell-1) plays an important role in neural crest-derived tissues and is strongly expressed in dental follicles. Nell-1 was originally identified in pathologically fused and fusing sutures of patients with unilateral coronal synostosis, and it plays indispensable roles in bone remodeling, including roles in osteoblast differentiation, bone formation and regeneration, craniofacial skeleton development, and the differentiation of many kinds of stem cells. Runx2 was proven to directly target the Nell-1 gene and regulate its expression. These studies suggested that Runx2/Nell-1 axis may play an important role in the process of tooth eruption by affecting DFPCs. Studies on short and long regulatory noncoding RNAs have revealed the complexity of RNA-mediated regulation of gene expression at the posttranscriptional level. This ceRNA network participates in the regulation of Runx2 and Nell-1 gene expression in a complex way. However, non-study indicated the potential connection between Runx2 and Nell-1, and further researches are still needed. Keywords: Tooth eruption, RUNX2/Runx2, NELL-1/Nell-1, Dental follicles (DFs), Dental follicle progenitor cells (DFPCs), Neural crest, Osteoblast, Osteoclast, Bone remodeling, Noncoding RNAs (ncRNAs), Competitive endogenous RNAs (ceRNAs)
An efficient formation of synthetically and biologically relevant β‐ketosulfones via a photo‐mediated decarboxylative ketonization of atropic acids was disclosed. The approach features metal‐free ...conditions, good functional group compatibility, readily available starting materials and the use of ubiquitous dioxygen as both oxygen source and oxidant. Furthermore, mechanistic studies reveal that the decarboxylative ketonization reaction proceeds via a radical mechanism and may involve a radical chain reaction.
Sustained elevation of corticosterone (CORT) is one of the common causes of aging and major depression disorder. However, the role of elevated CORT in late life depression (LLD) has not been ...elucidated. In this study, 18-month-old female rats were subjected to bilateral adrenalectomy or sham surgery. Their CORT levels in plasma were adjusted by CORT replacement and the rats were divided into high-level CORT (H-CORT), low-level CORT (L-CORT), and Sham group. We showed that L-CORT rats displayed attenuated depressive symptoms and memory defects in behavioral tests as compared with Sham or H-CORT rats. Furthermore, we showed that glutamatergic transmission was enhanced in L-CORT rats, evidenced by enhanced population spike amplitude (PSA) recorded from the dentate gyrus of hippocampus in vivo and increased glutamate release from hippocampal synaptosomes caused by high frequency stimulation or CORT exposure. Intracerebroventricular injection of an enzymatic glutamate scavenger system, glutamic-pyruvic transmine (GPT, 1 μM), significantly increased the PSA in Sham rats, suggesting that extracelluar accumulation of glutamate might be the culprit of impaired glutamatergic transmission, which was dependent on the uptake by Glt-1 in astrocytes. We revealed that hippocampal Glt-1 expression level in the L-CORT rats was much higher than in Sham and H-CORT rats. In a gradient neuron-astrocyte coculture, we found that the expression of Glt-1 was decreased with the increase of neural percentage, suggesting that impairment of Glt-1 might result from the high level of CORT contributed neural damage. In sham rats, administration of DHK that inhibited Glt-1 activity induced significant LLD symptoms, whereas administration of RIL that promoted glutamate uptake significantly attenuated LLD. All of these results suggest that glutamatergic transmission impairment is one of important pathogenesis in LLD induced by high level of CORT, which provide promising clues for the treatment of LLD.
The research of external fingerprint collected by total internal reflection (TIR) has been carried out for decades and the research of internal fingerprint collected by optical coherence tomography ...(OCT) has just begun. The internal fingerprint can be hardly affected by the finger surface status, due to its strong antiinterference and antispoofing ability, which can serve as a powerful supplement to external fingerprint. However, matching fingerprints acquired in different ways can lead to a drop in fingerprint recognition accuracy due to the differences in fingerprint quality, distortions, and detection areas. Whether the internal fingerprint can be used to replace the external fingerprint for direct identification has been hampered by lacking comparison tools to study potential correlation with each other. To study the connection between internal and external fingerprints, a synchronous acquisition system that achieves the same fingerprint area measurement at the same time is necessary. The integration of different optical paths of TIR and OCT as well as the consequent distortion correction of two totally different imaging ways are two challenging problems. This article presents a fingerprint acquisition system that synchronously acquires the external fingerprint and internal fingerprint with TIR and OCT, respectively. By using a self-designed trapezoidal prism, optical paths of TIR and OCT were integrated. Furthermore, a distortion correction method based on a grid calibration plate is used to remove distortions caused by two imaging methods. The fingerprint quality statistics are illustrated in 264 sets of fingerprint data sets. Identification results show synchronous acquisition and distortion correction of the proposed system are efficient.
As one of main active learning methods, zero-shot target recognition with synthetic aperture radar (SAR) data has received considerable attention in recent years. Its goal is to distinguish new ...targets from the known classes without requiring additional training data. Existing zero-shot learning (ZSL) methods perform well on optical targets, but they fail to recognize zero-shot SAR targets. Due to the strong similarity of SAR targets between different classes, the ZSL task usually suffers from the distribution concentration problem. To tackle this problem, a Dual Branch Auto-Encoder (DBAE) network is proposed in this letter. DBAE effectively alleviates the distribution concentration problem by adding a classification assistance net. Its dual branch structure is specially designed for further improving the intra-class similarity and inter-class dissimilarity of SAR targets in the embedding space. By training with the defined hybrid loss function, DBAE automatically builds a stable embedding space. Extensive experiments on the public data set of Moving and Stationary Target Acquisition and Recognition (MSTAR) show that DBAE is of rational design and provides better or comparable ZSL recognition results.
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