Time-dependent Effect of Graphene on the Microbial Activity of the Soil Under Single and Repeated Exposures

Graphene (GR) has huge industrial and biomedical potential, and its adverse effect on soil microorganisms has been evaluated in ecotoxicological studies. These studies focus on a single exposure to GR, but repeated exposures are more likely to occur. In this study, we compared the impact of single and repeated exposures of GR on structure, abundance and function of soil bacterial community based on soil enzyme activity and high-throughput sequencing. The activities of urease and fluorescein diacetate esterase and alpha diversity demonstrate that repeated exposure to GR increase the diversity of soil bacteria. The PCoA and sample level clustering tree showed single exposure to GR after 4 days alter the soil bacterial community to some extent. During the entire incubation process, no matter what kind of exposure scenarios to GR, the majority of bacterial phylotypes remained unchanged except for Proteobacteria and Actinobacteria according to the relative abundance of phylotypes.

Simultaneous High Dynamic Range Algorithm, Testing, and Instrument Simulation

Within an imaging instrument’s field of view, there may be many observational targets of interest. Similarly, within a spectrograph’s bandpass, there may be many emission lines of interest. The brightness of these targets and lines can be orders of magnitude different, which poses a challenge to instrument and mission design. A single exposure can saturate the bright emission and/or have a low signal-to-noise ratio (S/N) for faint emission. Traditional high dynamic range (HDR) techniques solve this problem by either combining multiple sequential exposures of varied duration or splitting the light to different sensors. These methods, however, can result in the loss of science capability, reduced observational efficiency, or increased complexity and cost. The simultaneous HDR method described in this paper avoids these issues by utilizing a special type of detector whose rows can be read independently to define zones that are then composited, resulting in areas with short or long exposure measured simultaneously. We demonstrate this technique for the Sun, which is bright on disk and faint off disk. We emulated these conditions in the lab to validate the method. We built an instrument simulator to demonstrate the method for a realistic solar imager and input. We then calculated S/Ns, finding a value of 45 for a faint coronal mass ejection and 200 for a bright one, both at 3.5  ⊙ N —meeting or far exceeding the international standard for digital photography that defines an S/N of 10 as acceptable and 40 as excellent. Future missions should consider this type of hardware and technique in their trade studies for instrument design.

Combined Negative Effects of Microplastics and Plasticizer DEHP: the Increased Release of Nets Delays Wound Healing

Introduction: Environmental pollutants microplastics (MPs) and di (2-ethyl) hexyl phthalate (DEHP) can cause damage to multiple organs by causing oxidative stress. Oxidative stress participates in the healing of skin wounds through the release of neutrophil extranets (Nets). Here, we studied the effects of DEHP and MPs on skin wound healing in mice after single and combined exposure for 1 month. Results: The results showed that MPs delayed the healing of skin wounds, and the combination of the two delayed wound healing more significantly. The results of in vivo and in vitro experiments showed that the release of oxidative stress and Nets in the single exposure group increased, and the combined exposure group increased more. Further mechanism studies showed that the skin chemokines of the single exposure group increased, the NF-κB pathway was activated, the Wnt pathway was inhibited, and the epidermal growth factor and fibrosis-related indicators decreased. The combined exposure group showed a more obvious trend.Conclusion: In summary, the above results indicate that DEHP combined with MPs induces an increase in the release of Nets by causing excessive skin ROS production and increases the expression of chemokines and interferes with the expression of healing factors by regulating the NF-κB and Wnt pathways.

Transcriptomics of single dose and repeated carbon black and ozone inhalation co-exposure highlight progressive pulmonary mitochondrial dysfunction

Background Air pollution is a complex mixture of particles and gases, yet current regulations are based on single toxicant levels failing to consider potential interactive outcomes of co-exposures. We examined transcriptomic changes after inhalation co-exposure to a particulate and a gaseous component of air pollution and hypothesized that co-exposure would induce significantly greater impairments to mitochondrial bioenergetics. A whole-body inhalation exposure to ultrafine carbon black (CB), and ozone (O3) was performed, and the impact of single and multiple exposures was studied at relevant deposition levels. C57BL/6 mice were exposed to CB (10 mg/m3) and/or O3 (2 ppm) for 3 h (either a single exposure or four independent exposures). RNA was isolated from lungs and mRNA sequencing performed using the Illumina HiSeq. Lung pathology was evaluated by histology and immunohistochemistry. Electron transport chain (ETC) activities, electron flow, hydrogen peroxide production, and ATP content were assessed. Results Compared to individual exposure groups, co-exposure induced significantly greater neutrophils and protein levels in broncho-alveolar lavage fluid as well as a significant increase in mRNA expression of oxidative stress and inflammation related genes. Similarly, a significant increase in hydrogen peroxide production was observed after co-exposure. After single and four exposures, co-exposure revealed a greater number of differentially expressed genes (2251 and 4072, respectively). Of these genes, 1188 (single exposure) and 2061 (four exposures) were uniquely differentially expressed, with 35 mitochondrial ETC mRNA transcripts significantly impacted after four exposures. Both O3 and co-exposure treatment significantly reduced ETC maximal activity for complexes I (− 39.3% and − 36.2%, respectively) and IV (− 55.1% and − 57.1%, respectively). Only co-exposure reduced ATP Synthase activity (− 35.7%) and total ATP content (30%). Further, the ability for ATP Synthase to function is limited by reduced electron flow (− 25%) and translation of subunits, such as ATP5F1, following co-exposure. Conclusions CB and O3 co-exposure cause unique transcriptomic changes in the lungs that are characterized by functional deficits to mitochondrial bioenergetics. Alterations to ATP Synthase function and mitochondrial electron flow underly a pathological adaptation to lung injury induced by co-exposure.

The Effect of High-Dose-Rate Pulsed Radiation on the Survival of Clinically Relevant Radioresistant Cells

We demonstrated that low dose pulsed radiation (0.25 Gy) at a high-dose-rate, even for very short intervals (10 s), decreases cell survival to a greater extent than single exposure to a similar total dose and dose rate. The objective of this study was to clarify whether high-dose-rate pulsed radiation is effective against SAS-R, a clinically relevant radioresistant cell line. Cell survival following high-dose-rate pulsed radiation was evaluated via a colony assay. Flow cytometry was utilized to evaluate γH2AX, a molecular marker of DNA double-strand breaks and delayed reactive oxygen species (ROS) associated with radiation-induced apoptosis. Increased cytotoxicity was observed in SAS-R and parent SAS cells in response to high dose rate pulsed radiation compared to single dose, as determined by colony assays. Residual γH2AX in both cells subjected to high-dose-rate pulsed radiation showed a tendency to increase, with a significant increase observed in SAS cells at 72 h. In addition, high-dose-rate pulsed radiation increased delayed ROS more than the single exposure did. These results indicate that high-dose-rate pulsed radiation was associated with residual γH2AX and delayed ROS, and high-dose-rate pulsed radiation may be used as an effective radiotherapy procedure against radioresistant cells.

Does Exposure to General Anesthesia Increase Risk of ADHD for Children Before Age of Three?

Objective: The objective of the study was to evaluate the relationship between frequency of exposure to general anesthesia before the age of 3 and subsequent risk of diagnosis for attention-deficit hyperactivity disorder (ADHD).Method: We searched PubMed, Embase, Web of Science, and Cochrane Library database for eligible inclusion in the meta-analysis. The indicated outcomes were extracted from the included studies, and the combined effects were calculated using the RevMan software 5.3.Results: Compared with no exposure to general anesthesia, single exposure to general anesthesia did not increase the risk of ADHD for children before the age of 3 [hazard ratio (HR): 1.14, 95%; confidence intervals (CI): 0.97–1.35; p = 0.11; I2 = 0%], while multiple exposures to general anesthesia did increase the risk of ADHD (HR: 1.83; 95% CIs: 1.00–3.32; p = 0.05; I2 = 81%).Conclusion: Multiple, but not single, exposures to general anesthesia in children before age of 3 increased the risk of ADHD.