Effect of abrasive particle arrangement on surface morphology ground with pyramid belt

To study the influence of grain arrangement on the surface profile of the workpiece, a mathematical model and its corresponding analytical algorithm of pyramidal abrasive belt grinding were established. The roughness value was simulated and predicted with Abaqus software. Grinding tests were carried out on the robot grinding system platform with pyramidal abrasive belt, and the surface profile were inspected and then compared with the simulation. The results show that the simulated roughness and the measured values have similar variation trend with good consistency, where the error is within 0.03 μm and the maximum error rate is 16.6%. The theoretical simulation and test results remain consistent, indicating that the model could be used to predict the surface roughness of workpiece ground with pyramidal abrasive belt

Chronic Administration of Benzo(a)pyrene Induces Memory Impairment and Anxiety-Like Behavior and Increases of NR2B DNA Methylation.

Recently, an increasing number of human and animal studies have reported that exposure to benzo(a)pyrene (BaP) induces neurological abnormalities and is also associated with adverse effects, such as tumor formation, immunosuppression, teratogenicity, and hormonal disorders. However, the exact mechanisms underlying BaP-induced impairment of neurological function remain unclear. The aim of this study was to examine the regulating mechanisms underlying the impact of chronic BaP exposure on neurobehavioral performance.C57BL mice received either BaP in different doses (1.0, 2.5, 6.25 mg/kg) or olive oil twice a week for 90 days. Memory and emotional behaviors were evaluated using Y-maze and open-field tests, respectively. Furthermore, levels of mRNA expression were measured by using qPCR, and DNA methylation of NMDA receptor 2B subunit (NR2B) was examined using bisulfate pyrosequencing in the prefrontal cortex and hippocampus.Compared to controls, mice that received BaP (2.5, 6.25 mg/kg) showed deficits in short-term memory and an anxiety-like behavior. These behavioral alterations were associated with a down-regulation of the NR2B gene and a concomitant increase in the level of DNA methylation in the NR2B promoter in the two brain regions.Chronic BaP exposure induces an increase in DNA methylation in the NR2B gene promoter and down-regulates NR2B expression, which may contribute to its neurotoxic effects on behavioral performance. The results suggest that NR2B vulnerability represents a target for environmental toxicants in the brain

Advances in Pharmacokinetic Mechanisms of Transporter-Mediated Herb-Drug Interactions

As the use of herbs has become more popular worldwide, there are increasing reports of herb-drug interactions (HDIs) following the combination of herbs and drugs. The active components of herbs are complex and have a variety of pharmacological activities, which inevitably affect changes in the pharmacokinetics of chemical drugs in vivo. The absorption, distribution, metabolism, and excretion of drugs in vivo are closely related to the expression of drug transporters. When the active components of herbs inhibit or induce the expression of transporters, this can cause changes in substrate pharmacokinetics, resulting in changes in the efficacy and toxicity of drugs. In this article, the tissue distribution and physiological functions of drug transporters are summarized through literature retrieval, and the effects of herbs on drug transporters and the possible mechanism of HDIs are analyzed and discussed in order to provide ideas and a reference for further guiding of safe clinical drug use

Organic extracts in PM2.5 are the major triggers to induce ferroptosis in SH-SY5Y cells

As a major air pollutant, PM2.5 can induce apoptosis of nerve cells, causing impairment of the learning and memory capabilities of humans and animals. Ferroptosis is a newly discovered way of programmed cell death. It is unclear whether the neurotoxicity induced by PM2.5 is related to the ferroptosis of nerve cells. In this study, we observed the changes in ferroptosis hallmarks of SH-SY5Y cells after exposure to various doses (40, 80, and 160 μg/mL PM2.5) for 24 h, exposure to 40 μg/mL PM2.5 for various times (24, 48, and 72 h), as well as exposure to various components (Po, organic extracts; Pw, water-soluble extracts; Pc, carbon core component). The results showed that PM2.5 reduced the cell viability, the content of GSH, and the activity of GSH-PX and SOD in SH-SY5Y cells with exposure dose and duration increasing. On the other hand, PM2.5 increased the content of iron, MDA, and the level of lipid ROS in SH-SY5Y cells with exposure dose and duration increasing. Additionally, PM2.5 reduced the expression levels of HO-1, NRF2, SLC7A11, and GPX4. The ferroptosis inhibitors Fer-1 and DFO significantly increase the cells viabilities and significantly reversed the changes of other above ferroptosis hallmarks. We also observed the different effects on ferroptosis hallmarks in the SH-SY5Y cells exposed to PM2.5 (160 μg/mL) and its various components (organic extracts, water-soluble extracts, and carbon core) for 24 h. We found that only the organic extracts shared similar results with PM2.5 (160 μg/mL). This study demonstrated that PM2.5 induced ferroptosis of SH-SY5Y cells, and organic extracts might be the primary component that caused ferroptosis

Effects of BaP on DNA methylation of the NR2B gene promoter.

<p>(A) Schematic diagram of selected CpG sites in the mouse NR2B gene promoter. Letters a-c represent the three regions in the NR2B promoter, respectively (Qiang et al., 2010). Each bar represents an individual CpG. The black bars represent a significant increase in methylation and the empty bars represent unchanged levels of methylation. The level of DNA methylation in the NR2B promoter was determined by pyrosequencing. The relative levels of NR2B methylation per CpG sites were assessed in the PFC (B) and hippocampus (C). Data are shown as the average of 5 separate experimental animals. Values are presented as the means ± SEM and represent the fold increase over the control group (control = 1). *, <i>p</i> < 0.05; **, <i>p</i> < 0.01 compared with control levels.</p

The effects of BaP on mice behavior.

<p>An open field test was used to evaluate the animal’s behavioral performance, including total grids (A), number (B) and latency (C) of entry to the central area, and the length of time in the periphery zone (D). n = 9 per BaP-treated group, n = 10 in control. Values are mean ± SEM. *, <i>p</i> < 0.05 compared to CTL.</p

BaP impaired short-time memory in the Y-maze test.

<p>(A) A schematic view of Y-maze with three arms, i.e., A, B, and C. (B) Y-maze test was used to evaluate short-term memory of the animals after BaP chronic exposure. Percentages of spontaneous alternation (%) were calculated and the values are presented as the mean ± SEM. *, <i>p</i> < 0.05 compared to CTL.</p

BaP exposure decreases the level of NR2B gene transcription in the PFC and hippocampus.

<p>Total RNA was isolated from the two brain regions. NR2B mRNA expression was determined by RT-qPCR, and 18S was used as an internal control. The results are presented as the average ratio vs. control ± SEM of seven independent experimental animals; *, <i>p</i> < 0.05; **, <i>p</i> < 0.01 compared with control levels.</p

Characteristics of bacterial community in eyelashes of patients with Demodex blepharitis

Abstract Background Demodex blepharitis (DB) is a common disease of the ocular surface. The characteristics of the bacterial community in eyelash roots after Demodex infestation are still unknown. Knowledge of the characteristics of the bacterial community of eyelash follicles in patients with DB can provide valuable insights for guiding the diagnosis and treatment of DB. Methods Twenty-five patients with DB (DB group) and 21 non-DB volunteers (control group) were enrolled in the study. Eyelashes from the upper eyelid of the right eye were sampled, and 16S ribosomal DNA (rDNA) sequencing was performed to determine the V3-V4 regions of the microbial 16S rDNA gene within 1 month of infestation. The sequencing data of the two groups were analyzed and compared. The effect of the bacterium Burkholderia on the survival of Demodex mites was evaluated using Demodex obtained from 12 patients with DB other that the patients in the DB group. Results A total of 31 phyla and 862 genera were identified in the DB and control groups. The five most abundant phyla in the two groups were Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes and Cyanobacteria. The abundance of Actinomycetes was significantly higher in the DB group than in the control group. At the genus level, the five most abundant genera in the two groups were Pseudomonas, Burkholderia-Caballeronia-Paraburkholderia, Rolstonia and Acinetobacter; Clostridium sensu stricto 1 was abundant in the control group and Corynebacterium_1 was abundant in the DB group. Compared with the control group, the abundance of Burkholderia-Caballeronia-Paraburkholderia was 2.36-fold lower in the DB group. Linear discriminant analysis Effect Size (LEfSe) analysis revealed Burkholderia-Caballeronia-Paraburkholderia, SC_I_84_unclassified, Nonmyxobacteria and Succinvibrio to be the major biomarkers in the control group and Catenibacterium and Lachnospiraceae NK4A136 group to be the major biomarkers in the DB group. To explore the performance of these optimal marker models, receiver operational characteristic curve analysis was performed, and the average area under the curve value of Burkholderia-Caballeronia-Paraburkholderia was 0.7448. Burkholderia cepacia isolated from normal human eyelashes was fermented, and the Demodex mites isolated from patient eyelashes were cultured together with its fermented supernatant. The results showed that the fermentation supernatant could significantly reduce the survival time of the Demodex mites, suggesting the potential therapeutic value of this bacterium against Demodex. Conclusions The composition of the bacterial community in the eyelashes of DB patients differed from that in eyelashes of healthy volunteers, revealing a decrease in bacterial diversity in infested eyelashes. This decrease may be related to the occurrence and development of DB. The supernatant of Burkholderia cepacia culture medium was found to inhibit the growth of Demodex in eyelash hair follicles, providing a new insight with potential applications for the clinical treatment of Demodex infestation. Graphical Abstrac