In this study, we investigated how Roux‐en‐Y gastric bypass (RYGB) enhances glucagon‐like peptide 1 (GLP‐1) response in GK rats and explored the potential link between RYGB‐stimulated BAs/FXR ...signalling and GLP‐1R‐linked signalling in β‐cells, a key pathway that regulates glucose‐stimulated insulin secretion (GSIS). Here we show that RYGB restores GLP‐1R expression in GK rat islets. This involves increased total BAs as well as chenodeoxycholic acid (CDCA), leading to FXR activation, increasing FXR binding to the promoter of Glp‐1r and enhancing occupancy of histone acetyltransferase steroid receptor coactivator‐1 (SRC1), thus increasing histone H3 acetylation at the promoter. These coordinated events bring about increased GLP‐1R expression, resulting in greater GLP‐1 response in β‐cells. Moreover, ablation of FXR suppressed the stimulatory effects of GLP‐1. Thus, this study unravels the crucial role of the BAs/FXR/SRC1 axis‐controlled GLP‐1R expression in β‐cells, which results in enhanced incretin effect and normalized blood glucose of GK rats after RYGB.
Co-pyrolysis of lignin and waste plastics, for example polyethylene (PE), has been studied, but related reports are basically on condition optimizations. This study revealed a new perspective on ...PE-promoted lignin pyrolysis to phenolic monomers with mass transfer and radical explanation. Lignin and PE were first pyrolyzed individually to identify pyrolysis characteristics, pyrolytic products, as well as the suitable co-pyrolysis temperature. Then, co-pyrolysis of blended lignin/PE with various ratios was investigated. Yields of lignin products reached the maximum under lignin/PE ratio of 1:1, but blended approach always inhibited the production of lignin phenols. This resulted from the poor mass transfer and interactions between lignin and PE, in which PE pyrolysates could easily escape from the particle gaps. While in layered approach, PE pyrolysates had to pass through the lignin layer which contributed to the good interactions with lignin pyrolysis intermediates, thus the yields of lignin-derived products were significantly improved. Interactions between lignin and PE (or their pyrolysates) were mainly radical quenching reactions, and X-ray photoelectron spectrum (XPS) and electron paramagnetic resonance (EPR) of pyrolytic chars were conducted to verify these interactions controlled by mass transfer. The percentage of CC (sp2) and concentration of organic stable radicals in layered lignin/PE char were both the lowest compared with those in blended lignin/PE and lignin char, indicating the stabilization of lignin-derived radicals by PE pyrolysates. Moreover, the spin concentration of radicals in the char from layered char/PE was lower than that in lignin char, which further affirmed the quenching of radicals by PE in the layered co-pyrolysis mode.
Mass transfer and radical reactions together controlled the co-pyrolysis of lignin and PE. Good mass transfer in layered lignin/PE co-pyrolysis approach promoted the radical quenching reactions and favored the formation of lignin-derived phenols. Display omitted
•Mass transfer and radical reactions together controlled lignin/PE co-pyrolysis.•Layered lignin/PE demonstrated the highest yields and lowest radical concentrations.•Possible reaction pathways of PE-promoted lignin pyrolysis were proposed.
Meteorological conditions and source emissions in grassland areas are quite different from those in urban areas, which significantly impacts the spatiotemporal characteristics of black carbon (BC). ...To obtain the characteristics of BC in the typical grassland environment in China, continuous observations of BC were carried out in Etuoke Banner, a typical grassland environment in Ordos, from September 8 to December 1, 2022. BC in Etuoke Banner in autumn is 22.4–4667.5 ng m−3, and the average concentration is 456.6 ng m−3, accounting for 2.20% of the mass fraction of PM2.5. BCliquid (BC generated from the combustion of liquid fuels) is the main component of BC (accounting for 79.2%); the average concentration is 361.7 ng m−3. The diurnal variations of BC, BCliquid, and BCsolid (BC generated from the combustion of solid fuels) are bimodal, with peaks at 08:00 and 18:00. The first peak is mainly related to traffic sources, cooking sources, and incomplete combustion of carbon‐containing substances; the second peak may be caused by emissions from residential cooking sources under the influence of meteorological conditions unfavorable to diffusion. The diurnal variation of absorption Ångström exponent (AAE) is unimodal, with the peak at 14:00. With the increase in BC mass concentration, AAE and visibility gradually decreased, wind speed first decreased and then increased, P and RH gradually increased, and the contribution of biomass combustion sources to BC decreased. In contrast, the contribution of traffic sources to BC increased. The evolution characteristics of atmospheric pollutants differed with the increase in BC concentration. The potential sources and affecting areas of BC and PM2.5 are mainly concentrated around Etuoke Banner and can affect the North China Plain after 48 h of transmission.
Observational study of BC aerosols during autumn in the grassland of Ordos, China.
Low-level viremia (LLV) ranging from 50 to 1,000 copies/ml is common in most HIV-1-infected patients receiving antiretroviral therapy (ART). However, the source of LLV and the impact of LLV on the ...HIV-1 reservoir during ART remain uncertain. We hypothesized that LLV may arise from the HIV reservoir and its occurrence affect the composition of the reservoir after LLV episodes. Accordingly, we investigated the genetic linkage of sequences obtained from plasma at LLV and pre-ART time points and from peripheral blood mononuclear cells (PBMCs) at pre-ART, pre-LLV, LLV, and post-LLV time points. We found that LLV sequences were populated with a predominant viral quasispecies that accounted for 67.29%∼100% of all sequences. Two episodes of LLV in subject 1, spaced 6 months apart, appeared to have originated from the stochastic reactivation of latently HIV-1-infected cells. Moreover, 3.77% of pre-ART plasma sequences were identical to 67.29% of LLV-3 plasma sequences in subject 1, suggesting that LLV may have arisen from a subset of cells that were infected before ART was initiated. No direct evidence of sequence linkage was found between LLV viruses and circulating cellular reservoirs in all subjects. The reservoir size, diversity, and divergence of the PBMC DNA did not differ significantly between the pre- and post-LLV sampling points ( P > 0.05), but the composition of viral reservoir quasispecies shifted markedly before and after LLV episodes. Indeed, subjects with LLV had a higher total PBMC DNA level, greater viral diversity, a lower proportion of variants with identical sequences detected at two or more time points, and a shorter variant duration during ART compared with subjects without LLV. Overall, our findings suggested that LLV viruses may stem from an unidentified source other than circulating cellular reservoirs. LLV episodes may introduce great complexity into the HIV reservoir, which brings challenges to the development of treatment strategies.
Selective oxidation of lignin is increasingly investigated due to its advantage of retaining the aromatic rings to produce value-added platform chemicals. In this paper, oxovanadium complexes ...catalyzed oxidation of lignin and lignin dimers in acetonitrile/water system under O
2
was reported. Under optimal conditions of VO(acac)
2
catalyzed oxidation, 95 mol% of lignin dimer 2-phenoxy acetophenone was converted, producing 43 mol% of phenol and 83 mol% of benzoic acid. The catalytic ability of V(acac)
3
was higher than that of VO(acac)
2
, but it caused heavier repolymerization and lower product yields. VO(acac)
2
catalyzed oxidation system also cleaved various
β
-O-4 lignin dimers, achieving > 95 mol% conversion. Whereas, yields of phenols from these dimers were lower than 5 mol%. These phenolics were shown to polymerize under reaction conditions. Furthermore, this oxidation system depolymerized poplar organosolv lignin. After oxidation, aromatic and C-O aliphatic functionalities in the heavy fractionation largely disappeared, and the weight-average molecular weight decreased from 5720 to 1140 Da.
Graphical abstract
Oxovanadium complexes show the good ability for the catalytic oxidation of lignin and lignin dimers in MeCN/H
2
O co-solvent in the presence of O
2
, achieving higher than 95 mol% conversion of
β
-O-4 lignin dimers and lowering the molecular weight of poplar organosolv lignin from 5720 to 1140 Da.
The tuning of the properties of MgAl2O4-based materials has aroused great attention in the field of engineering technology. Along these lines, magnesia and alumina were used as raw materials to ...prepare spinel by the solid-phase sintering method at 1500–1600 °C. Particularly, the impacts of the different MgO/Al2O3 molar ratios on the microstructural densification, sintering process and mechanical property of the fabricated materials were systematically studied. The results showed that the stoichiometric spinel with the highest concentration of ion diffusion possessed the best densification. And the magnesium-rich spinel displayed the better densification following with the formation of solid-solution, while the aluminum-rich spinel exhibited the worst ability in forming the solid-solution. Moreover, the different molar ratios changed the microstructure of the spinel, which induced the optimal sintering temperature of stoichiometric spinel to be at least 50 °C below that of the others. Specifically, in stoichiometric spinel, spinel grains grew up and formed obvious structure, which made the sintering process arrive at the end point and made the performance reach the best. Specifically, the flexural strength was 112.62 MPa and apparent porosity was 0.44%. However, no grown or developed spinel grains were observed for magnesium-rich/aluminum-rich spinels, which delayed the sintering process.
Adenylyl cyclase 8 (ADCY8) and Farnesoid X Receptor (FXR) have been identified in pancreatic β-cells and play important roles in insulin secretion. But the mechanisms underlying with respect to the ...regulation of ADCY8 expression in β-cells, particularly whether FXR is involved, remain unexplored. We now show that ADCY8 expression is decreased in Goto-Kakizaki (GK) rat islets compared with healthy Wistar controls. We also found that reduced ADCY8 is associated with decreased expression of FXR. Consistently, ADCY8 expression was suppressed by the knockdown of FXR in INS-1 832/13 cells, as well as the islets from FXR knockout mice. On the contrary, ADCY8 expression was increased in FXR-overexpressed INS-1 832/13 cells or in the case of FXR activation. Mechanistically, FXR directly binds to Adcy8 promoter and recruits the histone acetyltransferase Steroid Receptor Coactivator 1 (SRC1), thereby resulting in the increased acetylation of histone H3 in Adcy8 locus, promoting Adcy8 gene transcription in β-cells. Thus, this study indicates that FXR is a critical transcription factor that mediates ADCY8 expression in pancreatic β-cells and has characterized the chromatin modification associated with Adcy8 transcription.
Roux-en-Y gastric bypass surgery (RYGB) improves the first phase of glucose-stimulated insulin secretion (GSIS) in patients with type 2 diabetes. How it does so remains unclear. Farnesoid X receptor ...(FXR), the nuclear receptor of bile acids (BAs), is implicated in bariatric surgery. Moreover, the transient receptor potential ankyrin 1 (TRPA1) channel is expressed in pancreatic β-cells and involved in insulin secretion. We aimed to explore the role of BAs/FXR and TRPA1 in improved GSIS in diabetic rats after RYGB.
RYGB or sham surgery was conducted in spontaneous diabetic Goto-Kakizaki (GK) rats, or FXR or TRPA1 transgenic mice. Gene and protein expression of islets were assessed by qPCR and western blotting. Electrophysiological properties of single β-cells were studied using patch-clamp technique. Binding of FXR and histone acetyltransferase steroid receptor coactivator-1 (SRC1) to the TRPA1 promoter, acetylated histone H3 (ACH3) levels at the TRPA1 promoter were determined using ChIP assays. GSIS was measured using enzyme-linked immunosorbent assays or intravenous glucose tolerance test (IVGTT).
RYGB increases GSIS, particularly the first-phase of GSIS in both intact islets and GK rats in vivo, and ameliorates hyperglycemia of GK rats. Importantly, the effects of RYGB were attenuated in TRPA1-deficient mice. Moreover, GK β-cells displayed significantly decreased TRPA1 expression and current. Patch-clamp recording revealed that TRPA1−/− β-cells displayed a marked hyperpolarization and decreased glucose-evoked action potential firing, which was associated with impaired GSIS. RYGB restored TRPA1 expression and current in GK β-cells. This was accompanied by improved glucose-evoked electrical activity and insulin secretion. Additionally, RYGB-induced TRPA1 expression involved BAs/FXR-mediated recruitment of SRC1, promoting ACH3 at the promoter of TRPA1.
The BAs/FXR/SRC1 axis-mediated restoration of TRPA1 expression plays a critical role in the enhanced GSIS and remission of diabetes in GK rats after RYGB.
•RYGB-restored TRPA1 expression in diabetic β-cells.•RYGB-induced TRPA1 is mediated by FXR-SRC1-increased ACH3 at TRPA1 promoter.•TRPA1 is required for β-cell stimulus-secretion coupling.•Modulation of TRPA1 expression in β-cells may constitute a novel therapeutic strategy to improve β-cell function in T2D.
The latent heat produced by cloud microphysical processes can greatly affect the thermal and dynamic structure of the atmosphere, as well as the development and evolution of clouds and precipitation. ...In this study, to examine the consequences of different kinds of latent heat produced by microphysical processes, four sensitivity tests were conducted based on the control simulation results of a heavy rainstorm occurred in Beijing on 21 July 2012 using the Weather Research and Forecasting Model (WRF). Without the latent heat absorption of evaporation, the convective cloud system developed stronger, and the accumulated precipitation amount increased. Without the latent heat release of deposition, the transit time of the surface front was delayed; in addition, the convective cloud system developed weakly. The accumulated conversion amounts of microphysical processes and the accumulated rainfall amount in the deposition adiabatic test were far less than those in the other tests. Without the latent heat of melting and freezing, the convective cloud system did not change substantially, and there was only a minor effect on precipitation. Hydrometeor production exhibited some changes related to precipitation in the five tests. The latent heat produced by the convective system varied substantially in the five tests with a change in the latent heat budget.
The source of PM
2.5
varies at different stages of urban haze pollution. In addition, there is obvious regional transport of pollutants between urban agglomerations. PM
2.5
and its major chemical ...compositions in a regional haze episode were measured continuously from 16 to 27 November 2018 in Nanjing, China. The types of primary sources resolved by principal component analysis (PCA) and positive matrix factorization (PMF) were similar, and the result of PMF was more refined. The average contribution of each source by PMF was: secondary nitrate (64.01%), secondary sulfate (11.62%), incomplete combustion (4.49%), sea salt (8.61%), biomass burning (6.90%), and crustal dust (4.37%). In different haze stages, the distribution characteristics of air pollutants differed. The concentrations of SO
4
2-
, NO
3
−
, NH
4
+
, and black carbon were the highest in the haze developing stage, which was 2.0, 3.1, 3.0, and 2.4 times, respectively, higher than that under clean conditions. The increment of NO
3
−
dominated the development of haze, and the proportion of NO
3
−
from haze generation to development increased by 4.05%. The concentration contributions of secondary nitrate, sea salt, and biomass burning were highest in haze development, secondary sulfate was highest in haze generation, and incomplete combustion was highest in haze dissipation, which was 3.5, 1.8, 3.3, 1.7, and 9.5 times higher than the clean stage, respectively. In the haze episode, the contribution of crustal dust was lower than in the clean stage. Potential source contribution function (PSCF) and concentration weighted trajectory (CWT) revealed that the major source area of air pollutants in Nanjing came from the southeast, and the northwest was the major impact area.
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