Recent studies suggest that perfluoroalkyl substances (PFAS) and PFAS alternatives can cross the placental barrier. However, little is known on the differential patterns of trans-placental transfer ...(TPT) among conventional PFAS and PFAS alternatives in epidemiological study.
We aimed to characterize comprehensive TPT patterns in conventional PFAS and PFAS alternatives using matched maternal-cord blood serum from a birth cohort.
A total of 424 mother-fetus pairs were recruited from the Maoming Birth Cohort during 2015–2018. We detected 20 PFAS in cord and maternal serum using an ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). TPT of PFAS was calculated via cord to maternal serum concentration ratios.
Both of PFOS alternatives (chlorinated polyfluorinated ether sulfonates, Cl-PFESAs) and PFOA short-chain alternative (perfluorobutanoic acid, PFBA) were widely detected in the cord and maternal serum. In cord serum, the predominant PFAS was PFOS (1.93 ng/mL), followed by PFBA (1.45 ng/mL), PFOA (0.75 ng/mL) and 6:2 Cl-PFESA (0.32 ng/mL). We found that the PFAS alternatives had higher TPT than PFOS and PFOA, such as PFBA vs. PFOA (median: 1.41 vs. 0.73, P < 0.001) and 8:2 Cl-PFESA vs. PFOS (median: 0.98 vs. 0.42, P < 0.001). Moreover, the TPT of 8:2 Cl-PFESA was higher than the precursor, linear and isomeric PFOS, respectively (P < 0.01). Furthermore, we found a U-shaped pattern for TPT in perfluorocarboxylic acid compounds (PFCAs) across different length of carbon chain.
Our findings suggest that PFAS alternatives may be more easily across the placenta than conventional PFAS. Given the widespread usage of PFAS alternatives, our results indicate that more research is needed to assess the potential health risks of prenatal exposure to PFAS alternatives in children.
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•Examined trans-placental transfer (TPT) of PFAS and the alternatives systematically•PFAS alternatives were widely detected in maternal and cord serum.•Higher TPT was observed in the PFAS alternatives than those in PFOS and PFOA.
Abstract
Motivation
De novo peptide sequencing based on tandem mass spectrometry data is the key technology of shotgun proteomics for identifying peptides without any database and assembling unknown ...proteins. However, owing to the low ion coverage in tandem mass spectra, the order of certain consecutive amino acids cannot be determined if all of their supporting fragment ions are missing, which results in the low precision of de novo sequencing.
Results
In order to solve this problem, we developed pNovo 3, which used a learning-to-rank framework to distinguish similar peptide candidates for each spectrum. Three metrics for measuring the similarity between each experimental spectrum and its corresponding theoretical spectrum were used as important features, in which the theoretical spectra can be precisely predicted by the pDeep algorithm using deep learning. On seven benchmark datasets from six diverse species, pNovo 3 recalled 29–102% more correct spectra, and the precision was 11–89% higher than three other state-of-the-art de novo sequencing algorithms. Furthermore, compared with the newly developed DeepNovo, which also used the deep learning approach, pNovo 3 still identified 21–50% more spectra on the nine datasets used in the study of DeepNovo. In summary, the deep learning and learning-to-rank techniques implemented in pNovo 3 significantly improve the precision of de novo sequencing, and such machine learning framework is worth extending to other related research fields to distinguish the similar sequences.
Availability and implementation
pNovo 3 can be freely downloaded from http://pfind.ict.ac.cn/software/pNovo/index.html.
Supplementary information
Supplementary data are available at Bioinformatics online.
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•Incorporating APT nanorods into GO laminate created hierarchical microstructure.•Cheap natural APT as spacer to expand d-spacing thus improving water permeability.•A 4-fold water ...flux improvement with keeping high rejection of ∼100%.•Dyes were efficiently rejected by size exclusion and electrostatic interactions.
Graphene oxide/attapulgite (GO/APT) composite membranes were successfully fabricated by the vacuum-assisted filtration for efficient dyes wastewater treatment. By characterization of FTIR, XPS, Raman, XRD and FESEM, APT nanorods were confirmed to be incorporated into GO laminar layers via grafting modification, which would influence GO interlayer distance (d-spacing), membrane surface microstructure (laminate morphology, structure, and hydrophilicity) and even water separation performance. Comparison of those of pristine GO membrane, the calculated d-spacing of GO/APT membranes gradually increased from 0.90 nm to 1.07 nm, while water contact angles decreased from 71.0° to 43.3° with the increasing APT/GO ratios. Moreover, GO/APT membranes exhibited rough hierarchical microstructure and higher surface hydrophilicity, which was in conjunction with larger interlayer spacing to synergistically improve separation performance. The water permeated flux increased from 3.4 of pristine GO membrane to 13.3 L m−2 h−1 of GO/APT membrane with preserving high rejection nearly to 100% for 7.5 mg L−1 Rh B wastewater under optimized conditions. Similarly, membrane thickness, dye concentrations and separating species in feed solutions were also found to affect membrane separation performance. Dye molecules were efficiently rejected through GO/APT nanofiltration membranes by the synergistic separation mechanism: size exclusion effect because of the unimpeded water channels formed into 3D network laminate structure, and electrostatic interactions between the oxygen-containing functional groups on membrane surface and charged molecules. Such these GO/APT membranes demonstrated efficiently separation properties and thus provided new insight into the potential applications in water purification and dyes wastewater treatment.
SARS-CoV-2 may directly and indirectly damage lung tissue and other host organs, but there are few system-wide, untargeted studies of these effects on the human body. Here, we developed a ...parallelized mass spectrometry (MS) proteomics workflow enabling the rapid, quantitative analysis of hundreds of virus-infected FFPE tissues. The first layer of response to SARS-CoV-2 in all tissues was dominated by circulating inflammatory molecules. Beyond systemic inflammation, we differentiated between systemic and true tissue-specific effects to reflect distinct COVID-19-associated damage patterns. Proteomic changes in the lungs resembled those of diffuse alveolar damage (DAD) in non-COVID-19 patients. Extensive organ-specific changes were also evident in the kidneys, liver, and lymphatic and vascular systems. Secondary inflammatory effects in the brain were related to rearrangements in neurotransmitter receptors and myelin degradation. These MS-proteomics-derived results contribute substantially to our understanding of COVID-19 pathomechanisms and suggest strategies for organ-specific therapeutic interventions.
Since MXene (a two-dimensional material) was discovered in 2011, it has been favored in all aspects due to its rich surface functional groups, large specific surface area, high conductivity, large ...porosity, rich organic bonds, and high hydrophilicity. In this paper, the preparation of MXene is introduced first. HF etching was the first etching method for MXene; however, HF is corrosive, resulting in the development of the in situ HF method (fluoride + HCl). Due to the harmful effects of fluorine terminal on the performance of MXene, a fluorine-free preparation method was developed. The increase in interlayer spacing brought about by adding an intercalator can affect MXene’s performance. The usual preparation methods render MXene inevitably agglomerate and the resulting yields are insufficient. Many new preparation methods were researched in order to solve the problems of agglomeration and yield. Secondly, the application of MXene-based materials in gas sensors was discussed. MXene is often regarded as a flexible gas sensor, and the detection of ppb-level acetone at room temperature was observed for the first time. After the formation of composite materials, the increasing interlayer spacing and the specific surface area increased the number of active sites of gas adsorption and the gas sensitivity performance improved. Moreover, this paper discusses the gas-sensing mechanism of MXene. The gas-sensing mechanism of metallic MXene is affected by the expansion of the lamellae and will be doped with H2O and oxygen during the etching process in order to become a p-type semiconductor. A p-n heterojunction and a Schottky barrier forms due to combinations with other semiconductors; thus, the gas sensitivities of composite materials are regulated and controlled by them. Although there are only several reports on the application of MXene materials to gas sensors, MXene and its composite materials are expected to become materials that can effectively detect gases at room temperature, especially for the detection of NH3 and VOC gas. Finally, the challenges and opportunities of MXene as a gas sensor are discussed.
Distinction of non-self from self is the major task of the immune system. Immunopeptidomics studies the peptide repertoire presented by the human leukocyte antigen (HLA) protein, usually on tissues. ...However, HLA peptides are also bound to plasma soluble HLA (sHLA), but little is known about their origin and potential for biomarker discovery in this readily available biofluid. Currently, immunopeptidomics is hampered by complex workflows and limited sensitivity, typically requiring several mL of plasma. Here, we take advantage of recent improvements in the throughput and sensitivity of mass spectrometry (MS)-based proteomics to develop a highly sensitive, automated, and economical workflow for HLA peptide analysis, termed Immunopeptidomics by Biotinylated Antibodies and Streptavidin (IMBAS). IMBAS-MS quantifies more than 5000 HLA class I peptides from only 200 μl of plasma, in just 30 min. Our technology revealed that the plasma immunopeptidome of healthy donors is remarkably stable throughout the year and strongly correlated between individuals with overlapping HLA types. Immunopeptides originating from diverse tissues, including the brain, are proportionately represented. We conclude that sHLAs are a promising avenue for immunology and potentially for precision oncology.
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•Automated one-pot enrichment of soluble HLA peptides using magnetic beads (IMBAS).•Personalized computational library generation for DIA analysis using AlphaPeptDeep.•IMBAS-MS identifies more than 5000 HLA peptides form 200 μl of plasma.•Soluble HLA peptides represent a variety of tissues including the brain.
Soluble HLA (sHLA) peptides are thought to have great potential as biomarkers for different diseases such as cancer. However, efficient enrichment of sHLA peptides from body fluids like plasma has been a bottleneck, requiring 3 to 5 ml per person. Here, we present IMBAS-MS, an efficient and automated workflow for the enrichment of sHLA peptides from only 200 μl plasma. In combination with data-independent acquisition (DIA) and computational library-based analysis, we acquire deep immunopeptidomes from single measurements, elucidating its origins.
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Experimental evidence has shown that per- and polyfluoroalkyl substances (PFAS) alternatives and mixtures may exert hepatotoxic effects in animals. However, epidemiological evidence ...is limited. This research aimed to explore associations of PFAS and the alternatives with liver function in a general adult population. The study participants consisted of 1,303 adults from a community-based cross-sectional investigation in Guangzhou, China, from November 2018 to August 2019. We selected 13 PFAS with detection rates > 85% in serum samples and focused on perfluorooctane-sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and their alternatives 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA), 8:2 Cl-PFESA, and perfluorohexanoic acid (PFHxA) as predictors of outcome. Six liver function biomarkers (ALB, ALT, AST, GGT, ALP, and DBIL) were chosen as outcomes. We applied regression models with restricted cubic spline function to explore correlations between single PFAS and liver function and inspected the combined effect of PFAS mixtures on liver by applying Bayesian kernel machine regression (BKMR). We discovered positive associations among PFAS and liver function biomarkers except for ALP. For example, compared with the 25th percentile of PFAS concentration, the level of ALT increased by 12.36% (95% CI: 7.91%, 16.98%) for ln-6:2 Cl-PFESA, 5.59% (95% CI: 2.35%, 8.92%) for ln-8:2 Cl-PFESA, 3.56% (95% CI: −0.39%, 7.68%) for ln-PFHxA, 13.91% (95% CI: 8.93%, 19.13%) for ln-PFOA, and 14.25% (95% CI: 9.91%, 18.77%) for ln-PFOS at their 75th percentile. In addition, higher exposed serum PFAS was found to be correlated with greater odds of abnormal liver function. Analysis from BKMR models also showed an adverse association between PFAS mixtures and liver function. The combined effect of the PFAS mixture appeared to be non-interactive, in which PFOS was the main contributor to the overall effect. Our findings provide evidence of associations between PFAS alternatives, PFAS mixtures, and liver function in the general adult population.
Evidence on the association between long-term exposure to particulate matter with aerodynamic diameter ≤2.5 μm (PM2.5) and cardiovascular disease (CVD) is scarce in developing countries. Moreover, ...few studies assessed the role of the PM1 (≤1.0 μm) size fraction and CVD. We investigated the associations between PM1 and PM2.5 and CVD prevalence in Chinese adults.
In 2009, we randomly recruited 24,845 adults at the age of 18–74 years from 33 communities in Northeastern China. CVD status was determined by self-report of doctor-diagnosed CVD. Three-year (2006–08) average concentrations of PM1 and PM2.5 were assigned using a satellite-based exposure. We used spatial Generalized Linear Mixed Models to evaluate the associations between air pollutants and CVD prevalence, adjusting for multiple covariates. Stratified and interaction analyses and sensitivity analyses were also performed.
A 10 μg/m3 increase in long-term exposure to ambient PM1 levels was associated a 12% higher odds for having CVD (OR = 1.12; 95% CI = 1.05–1.20). Compared to PM1, association between PM2.5 and CVD was lower (OR = 1.06; 95% CI = 1.01–1.11). No significant association was observed for PM1–2.5 (1–2.5 μm) size fraction (OR = 0.98; 95% CI = 0.85–1.13). Stratified analyses showed greater effect estimates in men and the elder.
Long-term PM1 exposure was positively related to CVD, especially in men and the elder. In addition, PM1 may play a greater role than PM2.5 in associations with CVD. Further longitudinal studies are warranted to confirm our findings.
•Studies on PM1 and PM2.5 and cardiovascular disease (CVD) are scarce in China.•We conducted a cross-sectional study in 24,845 Chinese urban dwellers.•Associations of PM1 and PM2.5 with CVD were examined.•Long-term PM1 air pollution was associated with higher odds for CVD.•PM1 plays a greater role than PM2.5 in associations with CVD.
Nitrones are key intermediates in organic synthesis. Herein, we report the first photo‐redox synthesis of methylene nitrone intermediates from nitroarenes and arylamines. The highly reactive ...methylene nitrones are in situ trapped by alkenes to afford various isoxazolidines. This three‐component reaction features the use of N,N‐dimethylanilines or N‐aryl glycines as C1 building blocks, which allow for the one‐pot formal 1+2+2 cycloaddition from simple starting materials. A wide range of useful isoxazolidines can be obtained under mild conditions with moderate to good yields. Mechanistic investigations support the formation of methylene nitrone via selective N−CH3 bond cleavage and methylene transfer.
•A large population-based study was conducted in China to assess associations between PFASs exposure and eye diseases.•Exposure to PFASs especially isomers of PFOS and PFOA increases the odds of ...visual impairment.•Vitreous disorder was adversely associated with long-chain PFASs exposure.
The detrimental effects of perfluoroalkyl substances (PFASs) on several physiological systems have been reported, but the association of PFASs with eye, one of the most sensitive and exposed organ, has never been explored. To investigate the association between eye diseases including visual impairment (VI) and PFASs isomers, a cross-sectional stratified study was conducted in 1202 Chinese population, aged 22–96 years, from Shenyang, China. A standard protocol including Snellen vision chart, slit-lamp microscopy and direct ophthalmoscopy was used to examine eye diseases/conditions relating to anterior and posterior segment of eyes. In addition, we measured the blood concentrations of 19 linear and branched PFASs at one-time point. Results indicated that blood levels of PFASs were significantly higher in eye disease group than normal group. PFASs exposure were positively associated with both combined eye diseases and individual eye diseases. Among other PFASs, linear perfluorooctane sulfonate (n-PFOS; odds ratio OR = 3.37, 95% confidence interval CI: 2.50, 4.56), branched perfluorooctane sulfonate (Br-PFOS; OR = 2.25, 95% CI: 1.72, 2.93) and linear perfluorooctanoic acid (n-PFOA; OR = 1.79, 95% CI: 1.36, 2.37) significantly increases the odds of VI. Vitreous disorder was adversely associated with long-chain PFASs exposure. For example, perfluorotridecanoic acid (PFTrDA; OR = 1.86, 95% CI: 1.51, 2.29) and perfluorodecanoic acid (PFDA; OR = 1.79, 95% CI: 1.36, 2.36) showed the most significant association. In conclusion, this study suggests higher serum PFASs levels were associated with increase odds of VI and vitreous disorder in Chinese adults.
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