- Influence of titanium dioxide nanoparticles on the transport and deposition of microplastics in quartz sand. [Journal Article]
- EPEnviron Pollut 2019 Jul 09; 253:351-357
- The influence of titanium dioxide nanoparticles (nTiO2) on the transport and deposition of polystyrene microplastics (MPs) in saturated quartz sand was investigated in NaCl solutions with ionic stren…
The influence of titanium dioxide nanoparticles (nTiO2) on the transport and deposition of polystyrene microplastics (MPs) in saturated quartz sand was investigated in NaCl solutions with ionic strengths from 0.1 to 10 mM at two pH conditions (pH 5 and 7). Three different-sized polystyrene (PS) MPs (diameter of 0.2, 1, and 2 μm) were concerned in present study. We found that for all three different-sized MPs in NaCl solutions (0.1, 1 and 10 mM) at both pH 5 and 7, lower breakthrough curves and higher retained profiles of MPs with nTiO2 copresent in suspensions relative to those without nTiO2 were obtained, demonstrating that the copresence of nTiO2 in MPs suspensions decreased MPs transport and increased their deposition in quartz sand under all examined conditions. The mechanisms contributing to the increased MPs deposition with nTiO2 in suspensions at two pH conditions were different. The formation of MPs-nTiO2 heteroaggregates and additional deposition sites provided by previously deposited nTiO2 were found to drive to the increased MPs deposition with nTiO2 in suspensions at pH 5, while the formation of MPs-nTiO2 aggregates, additional deposition sites and increased surface roughness induced by the pre-deposited nTiO2 on quartz sand surfaces were responsible for the enhanced MPs deposition at pH 7. The results give insights to predict the fate and transport of different-sized MPs in porous media in the copresence of engineered nanoparticles.
- Spectroscopic and molecular modeling investigation on inhibition effect of nitroaromatic compounds on acetylcholinesterase activity. [Journal Article]
- CChemosphere 2019 Jul 13; 236:124365
- Nitroaromatic compounds (NACs) are widely distributed in the environment and are considered toxic or carcinogenic. However, little attention has been paid to the binding interactions between NACs and…
Nitroaromatic compounds (NACs) are widely distributed in the environment and are considered toxic or carcinogenic. However, little attention has been paid to the binding interactions between NACs and biomacromolecules (e.g., proteins). Here we investigated the effects of three model NACs, nitrobenzene (NB), 1,3-dinitrobenzene (DNB), and 1,3,5-trinitrobenzene (TNB), on the activity of acetylcholinesterase (AChE). The presence of NACs (up to 0.5 mM) effectively suppressed the AChE-catalyzed hydrolysis of acetylthiocholine iodide, with the suppression effect increasing with the nitro-group substitution (TNB > DNB > NB). Consistently, the UV absorption of AChE at 206 nm arising from the skeleton structure decreased by the addition NACs, and the decrease exhibited the same compound sequence, reflecting the perturbing interactions with the skeleton enzyme structure. However, no changes were made on the secondary structure of AChE, as evidenced by the circular dichroism analysis. The fluorescence quenching analysis of AChE demonstrated that NB and DNB interacted with both tryptophan (Trp) and tyrosine (Tyr) residues, whereas TNB interacted only with Trp. The UV absorption and fluorescence quenching analyses both reflected that the interactions with the non-skeleton aromatic amino acids were weak. 1H NMR analysis confirmed the strong π-π coupling interactions between TNB and model Trp. Molecular simulation indicated that the DNB or TNB molecule was sandwiched between Trp84 and Phe330 at the catalytic site via π-π coupling interactions. The findings highlight the importance of specific interactions of NACs with proteins to cause them to malfunction.
- Low concentration flufenamic acid enhances osteogenic differentiation of mesenchymal stem cells and suppresses bone loss by inhibition of the NF-κB signaling pathway. [Journal Article]
- SCStem Cell Res Ther 2019 Jul 19; 10(1):213
- CONCLUSIONS: Collectively, our study suggested that low concentration FFA could be used in bone tissue engineering or osteoporosis by promoting osteogenic differentiation of human MSCs.
- Identifying potential drug targets in hepatocellular carcinoma based on network analysis and one-class support vector machine. [Journal Article]
- SRSci Rep 2019 Jul 18; 9(1):10442
- Hepatocellular carcinoma (HCC) is one major cause of cancer-related death worldwide. But now, the systematic therapy for the advanced stages of HCC is rather limited. Thus, the discovery of novel dru…
Hepatocellular carcinoma (HCC) is one major cause of cancer-related death worldwide. But now, the systematic therapy for the advanced stages of HCC is rather limited. Thus, the discovery of novel drug targets and thereafter targeted drugs against HCC is continuously needed. In this study, we combined clinical association data, gene expression profiles and manually collected drug target genes with the human protein-protein interaction (PPI) network to establish an in-silico HCC drug target predictor. First, we found drug target genes (DTGs), disease-associated genes (DAGs), prognostic unfavorable genes (PUGs) and cancer up-regulated genes (URGs) have higher degree, betweenness, closeness centrality, while cancer down-regulated genes (DRGs), prognostic favorable genes (PFGs) have lower degrees, in comparison with background genes. Moreover, DTG nodes were shown to be closer to DAG, PUG and URG nodes, but farther away from PFG and DRG nodes. Compared to the background, PFGs and DRGs were shown to have relatively bigger genetic dependency scores, while PUGs and URGs have smaller genetic dependency scores. Finally, based on the observed features of DTGs, we constructed a drug target predictor using one-class support vector machine (one-class SVM). Performance evaluation results suggested our predictor could effectively identify putative drug target genes for further research.
- Mechanics of shape distortion of DLP 3D printed structures during UV post-curing. [Journal Article]
- SMSoft Matter 2019 Jul 18
- Digital light processing (DLP) three-dimensional (3D) printing technology has advantages of fast printing speed and high printing precision. It can print objects with small and complex geometrical fe…
Digital light processing (DLP) three-dimensional (3D) printing technology has advantages of fast printing speed and high printing precision. It can print objects with small and complex geometrical features and has been widely used in jewelry manufacturing and dentistry. In DLP printing, it is common to use post-treatment with UV light irradiation to improve the final mechanical properties. However, it was found that the UV post-curing process can lead to shape distortion and thus reduction of dimension accuracy. In this paper, we combined photopolymerization reaction kinetics and Euler-Bernoulli beam theory to study UV post-curing induced shape distortion of thin structures prepared by DLP 3D printing. Experiments were conducted to characterize the evolution of mechanical behavior of printed samples during the post-printing process, which was correlated to printing parameters (printing time of single-layer, height of single-layer and printing UV intensity), post-curing UV light intensity and the thickness of the strip. Moreover, post-curing induced distortion was used for the fabrication of 3D structures.
- Effects of temperature on the emission of particulate matter, polycyclic aromatic hydrocarbons, and polybrominated diphenyl ethers from the thermal treatment of printed wiring boards. [Journal Article]
- JHJ Hazard Mater 2019 Jul 08; 380:120849
- The effects of temperature on the emission of pollutants during the thermal treatment of electronic waste have rarely been investigated. The emission of particulate matter (PM), polycyclic aromatic h…
The effects of temperature on the emission of pollutants during the thermal treatment of electronic waste have rarely been investigated. The emission of particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs) from the thermal treatment of printed wiring boards was investigated over a temperature range of 320-600 °C. The emission factors (EFs) were determined to be within 1.6-7.6 g/kg, 2.23-11.9 μg/g, and 0.9-5.5 μg/g, respectively. High temperatures increased the formation of PAHs and CO, but decreased the emission of PBDEs, PM, and organic carbon. A temperature of 480 °C was determined to be optimal. Low-molecular-weight components were the dominant PAH species. The compositional profiles of PBDEs were clearly observed to vary with the temperature. Small particles (< 2.1 μm) that were more affected by temperature were dominant in PM, particle-bound PAHs, and PBDEs at all temperatures. High temperature increased the EFs of gaseous PAHs but had no remarkable effect on those of particulate PAHs. The freshly emitted PAHs primarily existed in the particulate phase at low temperatures, while the gaseous phase PAHs became prevailing at ≥ 520 °C. The particulate PBDEs were more susceptible to temperature and overwhelmingly dominant over the entire temperature range considered.
- Converging electrophysiological evidence for a processing advantage of social over nonsocial feedback. [Journal Article]
- CACogn Affect Behav Neurosci 2019 Jul 16
- We recently demonstrated a processing advantage of social versus nonsocial feedback stimuli in a western sample by assessing phase-locked neural responses. The current study extended our previous fin…
We recently demonstrated a processing advantage of social versus nonsocial feedback stimuli in a western sample by assessing phase-locked neural responses. The current study extended our previous findings to another cultural sample (Chinese) to further test whether non-phase-locked neural oscillations also exhibit the social feedback processing advantage. Fifty-three Chinese volunteers performed a time estimation task with social and nonsocial feedback stimuli (matched for complexity) while electroencephalogram was recorded. Almost entirely replicating our previous results, feedback ERPs showed a processing advantage for social compared with nonsocial stimuli. Importantly, non-phase-locked oscillations also revealed this pattern. Frontal midline theta (FMΘ) oscillations differentiated between negative and positive feedback to a larger extent in response to social compared with nonsocial feedback. The current findings imply a rather universal effect of social stimulus characteristics during feedback processing and further corroborate the notion of social content as a distinct stimulus category.
- Post-retrieval Extinction Prevents Reconsolidation of Methamphetamine Memory Traces and Subsequent Reinstatement of Methamphetamine Seeking. [Journal Article]
- FMFront Mol Neurosci 2019; 12:157
- Methamphetamine abuse has become a serious public health problem. However, effective treatment for methamphetamine addiction remains elusive, especially considering its high rate of relapse after tre…
Methamphetamine abuse has become a serious public health problem. However, effective treatment for methamphetamine addiction remains elusive, especially considering its high rate of relapse after treatment. A conditioned stimulus (CS) memory retrieval-extinction procedure has been demonstrated to decrease reinstatement of cocaine, heroin, and alcohol seeking in rats, and to reduce cue-induced cravings in heroin and nicotine addicts. The goal of the present study is to explore the effect of the CS memory retrieval-extinction procedure on methamphetamine seeking in rats and the underlying mechanisms. We found that daily retrieval of methamphetamine-associated memories 1 h before extinction sessions decreased subsequent drug priming-induced reinstatement, spontaneous recovery, and renewal of methamphetamine seeking. We also found that retrieval of methamphetamine-associated memories induced neuronal activation in the basolateral amygdala (BLA), while presenting extinction within the time window of reconsolidation abolished the neuronal activation in BLA. These results indicate that the CS memory retrieval-extinction procedure could prevent reconsolidation of methamphetamine memory traces in BLA and subsequent methamphetamine craving and relapse.
- Interactions between natural organic matter (NOM) and the cationic dye toluidine blue at varying pHs and ionic strengths: Effects of NOM charges and Donnan gel potentials. [Journal Article]
- CChemosphere 2019 Jul 04; 236:124272
- This study examined effects of charges of molecules of natural organic matter (NOM) on its interactions with organic cations represented by toluidine blue (TB). NOM was exemplified in this study by S…
This study examined effects of charges of molecules of natural organic matter (NOM) on its interactions with organic cations represented by toluidine blue (TB). NOM was exemplified in this study by Suwannee River (SR) and South Platte (SP) NOM. TB/NOM interactions were probed in the range of pH 3 to 11, DOC concentrations 0-10.6 mg L-1 and ionic strengths 0.001-0.1 mol L-1. Changes of TB absorbance at indicative wavelengths of 640 and 550 nm located in the characteristic absorbance band of TB and their ratio R640/550 were used to quantify TB/NOM binding and the formation of TB dimers and possibly higher order aggregates in the Donnan volume of NOM molecules. These effects were interpreted based on the modeling of NOM charges and their Donnan gel potentials (ψD). The spectroscopic and modeling data showed that TB/NOM binding can be quantified via a complexation model that reflects the extent of electrostatic attraction between TB cations and anionic NOM molecules. The dependence of the apparent formation constant vs. ionic strength was shown to be qualitatively correlated with the ψD potentials of NOM molecules.
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- Chiral features of metal phthalocyanines sitting atop the pre-assembled TiOPc monolayer on Ag(111). [Journal Article]
- PCPhys Chem Chem Phys 2019 Jul 16
- The chiral features of the top-layer TiOPc molecules on monolayered TiOPc assembly on Ag(111) were carefully investigated by scanning tunnelling microscopy and local work function measurements. Combi…
The chiral features of the top-layer TiOPc molecules on monolayered TiOPc assembly on Ag(111) were carefully investigated by scanning tunnelling microscopy and local work function measurements. Combined with the density functional theory calculations, systematic experimental explorations of the TiOPc/TiOPc, CuPc/TiOPc and TiOPc/CuPc systems on Ag(111) revealed that the chirality originated from asymmetric electronic interactions rather than conformational change, which might be related to the high performance of the photoelectronic devices based on the MPc complexes.