Exploration of the potential application of plutonium isotopes in source identification of sandstorm in the atmosphere of Beijing

Plutonium(Pu)is an anthropogenic radionuclide which mainly derived from atmospheric nuclear tests in the environment.In this study,the Pu isotopes(^(239)Pu and^(240)Pu)in aerosol samples collected during the sandstorm and non-sandstorm period were measured by accelerator mass spectrometry(AMS)and the behavior of Pu was studied.The activity concentrations of ^(239)Pu and ^(240)Pu in the aerosol samples of Beijing were ranged from 0.62 nB q/m^(3)to 99.6 n Bq/m^(3)for ^(239)Pu and 3.51 nBq/m^(3)to 60.23 n Bq/m^(3)for ^(240)Pu,respectively.^(239)Pu and ^(240)Pu concentrations exhibited a remarkable seasonal variation trend,with the higher results showed in spring,and the relatively lower concentrations in winter.The observed higher concentration of^(239)Pu and^(240)Pu detected in sandstorm samples further indicated Pu was closely related to the occurrence of sandstorms.The global fallout characteristics of^(240)Pu/^(239)Pu atom ratios(average0.20,ranging from 0.16 to 0.27)in aerosol samples indicating that global fallout was the major source of Pu in the atmosphere.Using aluminum(Al)as an indicator of soil resuspension,significant positive correlation between^(239)Pu and Al(r^(2)=0.934),240Pu and Al(^(r)2=0.525)revealed that soil resuspension was a primary source of atmospheric Pu in Beijing.These results implied that the combination of^(239)Pu,^(240)Pu and Al could be used as the potential tracer of sandstorm.

Exposure to perfluorooctane sulfonate reduced cell viability and insulin release capacity of β cells

Per-and polyfluoroalkyl substances(PFAS)are found to have multiple adverse outcomes on human health.Recently,epidemiological and toxicological studies showed that exposure to PFAS had adverse impacts on pancreas and showed association with insulin abnormalities.To explore how PFAS may contribute to diabetes,we studied impacts of perfluorooctane sul-fonate(PFOS)on cell viability and insulin release capacity of pancreatic β cells by using in vivo and in vitro methods.We found that 28-day administration with PFOS(10 mg/(kg body weight·day))caused reductions of pancreas weight and islet size in male mice.PFOS admin-istration also led to lower serum insulin level both in fasting state and after glucose infusion among male mice.For cell-based in vitro bioassay,we used mouse β-TC-6 cancer cells and found 48-hr exposure to PFOS decreased the cell viability at 50 μmol/L.By measuring insulin content in supernatant,48-hr pretreatment of PFOS(100 μmol/L)decreased the insulin re-lease capacity of β-TC-6 cells after glucose stimulation.Although these concentrations were higher than the environmental concentration of PFOS,it might be reasonable for high con-centration of PFOS to exert observable toxic effects in mice considering mice had a faster removal efficiency of PFOS than human.PFOS exposure(50 μmol/L)to β-TC-6 cells induced intracellular accumulation of reactive oxidative specie(ROS).Excessive ROS induced the re-active toxicity of cells,which eventually invoke apoptosis and necrosis.Results in this study provide evidence for the possible causal link of exposure to PFOS and diabetes risk.

Graphene quantum dots rescue protein dysregulation of pancreatic β-cells exposed to human islet amyloid polypeptide

The amyloid aggregation of peptides and proteins is a hallmark of neurological disorders and type 2 diabetes.Human islet amyloid polypeptide(IAPP),co-secreted with insulin by pancreaticβ-cells,plays dual roles in both glycemic control and the pathology of type 2 diabetes.While IAPP can activate the NLRP3 inflammasome and modulate cellular autophagy,apoptosis and extracellular matrix metabolism,no data is available concerning intracellular protein expression upon exposure to the polypeptide.More surprisingly,how intracellular protein expression is modulated by nanoparticle inhibitors of protein aggregation remains entirely unknown.In this study,we first examined the changing proteomes ofβTC6,a pancreaticβ-cell line,upon exposure to monomeric,oligomeric and fibrillar IAPP,and detailed cellular protein expression rescued by graphene quantum dots(GQDs),an IAPP inhibitor.We found that 29 proteins were significantly dysregulated by the IAPP species,while majority of these proteins were nucleotide-binding proteins.Collectively,our liquid chromatography tandem-mass spectrometry,fluorescence quenching,helium ion microscopy,cytotoxicity and discreet molecular dynamics simulations data revealed a remarkable capacity of GQDs in regulating aberrant protein expression through H-bonding and hydrophobic interactions,pointing to nanomedicine as a new frontier against human amyloid diseases.

Dechloranes exhibit binding potency and activity to thyroid hormone receptors

Dechloranes are a group of halogenated flame retardants with a basic bicyclo[2.2.1]heptene,including Dechlorane Plus(DP),Dechlorane 602(Dec 602),Dechlorane 603(Dec 603)and Dechlorane 604(Dec 604).A few epidemiological investigations and animal experiments have shown that DP exhibited thyroid-interfering effects.In the present study,we investigated whether DP and three other dechloranes could interfere the thyroid function through thyroid hormone receptors(TRs,TRαand TRβ)signaling pathways.The binding affinities of the four dechloranes to the two TRs were determined by fluorescence competitive binding assay.It was found that all the four dechloranes could bind with the two TRs.The relative potency(RP)values ranged from nd(not detectable)to 0.0667.Between the two TRs,dechloranes were more inclined to bind with TRβ,which implies that the thyroid interference effect of dechloranes may have selectivity in different tissues and organs.TRs-mediated luciferase reporter gene assay and T-screen assay showed that all the four dechloranes exhibited antagonistic activity to TRs in the cells.Taken together,our results demonstrated that dechloranes might interfere with thyroid function by binding with TRs and acting as TR antagonists.The health risk of highly exposed human populations should be of serious concern because of the high hazard quotient calculated from our cell assay results.

Zooming in to acquire micro-reaction:Application of microfluidics on soil microbiome

Microfluidics confers unique advantages in microbiological studies as these devices can accurately replicate the micro-and even nano-scale structures of soil to simulate the habitats of bacteria.It not only helps us understand the spatial distribution of bacterial communities(such as biofilms),but also provides mechanistic insights into microbial behaviors including chemotaxis and horizontal gene transfer(HGT).Microfluidics provides a feasible means for real-time,in situ studies and enables indepth exploration of the mechanisms of interactions in the soil microbiome.This review aims to introduce the basic principles of microfluidic technology and summarize the recent progress in microfluidic devices to study bacterial spatial distribution and functions,as well as biological processes,such bacterial chemotaxis,biofilm streamers(BS),quorum sensing(QS),and HGT.The challenges in and future development of microfluidics for soil microbiological studies are also discussed.