Spatial source, simulating improvement, and short-term health effect of high PM2.5 exposure during mutation event in the key urban agglomeration regions in China.

Air quality in China has significantly improved owing to the effective implementation of pollution control measures. However, mutation events caused by short-term spikes in PM2.5 in urban agglomeration regions continue to occur frequently. Identifying the spatial sources and influencing factors, as well as improving the prediction accuracy of high PM2.5 during mutation events, are crucial for public health. In this study, we firstly introduced discrete wavelet transform (DWT) to identify the mutation events with high PM2.5 concentration in the four key urban agglomerations, and evaluated the spatial sources for the polluted scenario using Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Additionally, DWT was combined with a widely used artificial neural network (ANN) to improve the prediction accuracy of PM2.5 concentration seven days in advance (seven-day forecast). Results indicated that mutation events commonly occurred in the northern regions during winter time, which were under the control of both short-range transportation of dirty airmass as well as negative meteorology conditions. Compared with the ANN model alone, the average band errors decreased by 9% when using DWT-ANN model. The average correlation coefficient (R) and root mean square error (RMSE) obtained using the DWT-ANN improved by 10% and 12% compared to those obtained using the ANN, indicating the efficiency and accuracy of simulating PM2.5, by combining the DWT and ANN. The short-term mortality during mutation events was then calculated, with the total averted all-cause, cardiovascular, and respiratory deaths in the four regions, being 4751, 2554, and 582 persons, respectively. A declining trend in prevented deaths from 2018 to 2020 demonstrated that the pollution intensity during mutation events gradually decreased owing to the implementation of the Three-Year Action Plan to Win the Blue Sky Defense War. The method proposed in this study can be used by policymakers to take preventive measures in response to a sudden increase in PM2.5, thereby ensuring public health.

Association of Postoperative Hypoglycemia With Mortality After Elective Craniotomy.

BACKGROUND AND OBJECTIVES: Hypoglycemia is a known risk of intensive postoperative glucose control in neurosurgical patients. However, the impact of postoperative hypoglycemia after craniotomy remains unexplored. This study aimed to determine the association between postoperative hypoglycemia and mortality in patients undergoing elective craniotomy. METHODS: This study involved adult patients who underwent elective craniotomy at the West China Hospital, Sichuan University, between January 2011 and March 2021. We defined moderate hypoglycemia as blood glucose levels below 3.9 mmol/L (70 mg/dL) and severe hypoglycemia as blood glucose levels below 2.2 mmol/L (40 mg/dL). The primary outcome was postoperative 90-day mortality. RESULTS: This study involved 15 040 patients undergoing an elective craniotomy. Overall, 504 (3.4%) patients experienced moderate hypoglycemia, whereas 125 (0.8%) patients experienced severe hypoglycemia. Multivariable analysis revealed that both moderate hypoglycemia (adjusted odds ratio [aOR] 1.86, 95% CI 1.24-2.78) and severe (aOR 2.94, 95% CI 1.46-5.92) hypoglycemia were associated with increased 90-day mortality compared with patients without hypoglycemia. Moreover, patients with moderate (aOR 2.78, 95% CI 2.28-3.39) or severe (aOR 16.70, 95% CI 10.63-26.23) hypoglycemia demonstrated a significantly higher OR for major morbidity after adjustment, compared with those without hypoglycemia. Patients experiencing moderate (aOR 3.20, 95% CI 2.65-3.88) or severe (aOR 14.03, 95% CI 8.78-22.43) hypoglycemia had significantly longer hospital stays than those without hypoglycemia. The risk of mortality and morbidity showed a tendency to increase with the number of hypoglycemia episodes in patients undergoing elective craniotomy (P for trend = .01, <.001). CONCLUSION: Among patients undergoing an elective craniotomy, moderate hypoglycemia and severe hypoglycemia are associated with increased mortality, major morbidity, and prolonged hospital stays. In addition, the risk of mortality and major morbidity increases with the number of hypoglycemia episodes.

Childhood adversity and depression of older adults: the moderating effect of social participation.

Objective: Examine the effect of childhood adversity on depression in older adults and the regulatory impact that social participation has on depression. Methods: Based on 6,704 standard-compliant research subjects, single factor analysis, multiple linear regression model, and tendency score matching were used to analyze the impact of childhood adversity on depression in older adults and the regulatory effect of social participation. Results: The depression rate is higher among women, young age, low education, unmarried, in agricultural households, older adults with low annual income, pre-retirement work type in agriculture, non-drinking, and those with two or more chronic diseases (p < 0.05). Children who experienced adversity as children are more likely to suffer from depression as adults (ß = 0.513, 0.590, 0.954, 0.983, 1.221, 0.953, 0.718; p < 0.05). Through the tendency score, the result is matched with the endogenous test. As well, older adults are more likely to suffer psychological damage from a greater number of childhood adversities in their early years (ß = 1.440, 2.646, 4.122; p < 0.001). It has been shown that social participation will reduce the negative impact of low-income family economic circumstances on depression among older adults of all ages (ß = -0.459,-0.567; p < 0.01), aggravate depression resulting from "neighborhood void of mutual assistance" and "no more fun to play" for older adults of all ages (ß = 1.024, 0.894; p < 0.01), and exacerbate depression resulting from "loneliness because there are no friends" for the oldest old (ß = 0.476, 0.779; p < 0.05). Conclusion: Older adults who experience childhood adversity are more likely to suffer from depression. Social participation plays a regulatory role in the relationship between childhood adversity and depression in older adults. For older adults' mental health to improve, family and social adversity should be prevented, and moderate participation in society should be encouraged.

Anthraquinones-based photocatalysis: A comprehensive review.

In recent years, there has been significant interest in photocatalytic technologies utilizing semiconductors and photosensitizers responsive to solar light, owing to their potential for energy and environmental applications. Current efforts are focused on enhancing existing photocatalysts and developing new ones tailored for environmental uses. Anthraquinones (AQs) serve as redox-active electron transfer mediators and photochemically active organic photosensitizers, effectively addressing common issues such as low light utilization and carrier separation efficiency found in conventional semiconductors. AQs offer advantages such as abundant raw materials, controlled preparation, excellent electron transfer capabilities, and photosensitivity, with applications spanning the energy, medical, and environmental sectors. Despite their utility, comprehensive reviews on AQs-based photocatalytic systems in environmental contexts are lacking. In this review, we thoroughly describe the photochemical properties of AQs and their potential applications in photocatalysis, particularly in addressing key environmental challenges like clean energy production, antibacterial action, and pollutant degradation. However, AQs face limitations in practical photocatalytic applications due to their low electrical conductivity and solubility-related secondary contamination. To mitigate these issues, the design and synthesis of graphene-immobilized AQs are highlighted as a solution to enhance practical photocatalytic applications. Additionally, future research directions are proposed to deepen the understanding of AQs' theoretical mechanisms and to provide practical applications for wastewater treatment. This review aims to facilitate mechanistic studies and practical applications of AQs-based photocatalytic technologies and to improve understanding of these technologies.

Design, synthesis and antimicrobial activity of novel berberine derivatives.

BACKGROUND: The threats to the safety of humans and the environment and the resistance of agricultural chemicals to plant pathogenic fungi and bacteria highlight an urgent need to find safe and efficient alternatives to chemical fungicides and bactericides. In this study, a series of Berberine (BBR) derivatives were designed, synthesized and evaluated for in vitro and in vivo antimicrobial activity against plant pathogenic fungi and bacteria. RESULTS: Bioassay results indicated that compounds A11, A14, A20, A21, A22, A25, A26, E1, E2, E3, Z1 and Z2 showed high inhibitory activity against Sclerotinia sclerotiorum and Botrytis cinerea. Especially, A25 showed a broad spectrum and the highest antifungal activity among these compounds. Its EC50 value against Botrytis cinerea was 1.34 µg mL-1. Compound E6 possessed high inhibitory activity against Xanthomonas oryzae and Xanthomonas Campestris, with MIC90 values of 3.12 µg mL-1 and 1.56 µg mL-1. A Topomer CoMFA model was generated for 3D-QSAR studies based on anti-B. cinerea effects, with high predictive accuracy, showed that the addition of an appropriate substituent group at the para-position of benzyl of BBR derivatives could effectively improve the anti-B. cinerea activity. In addition, compound A25 could significantly inhibit the spore germination of Botrytis cinerea at low concentration, and compound F4 exhibited remarkable curative and protective efficiencies on rice bacterial leaf blight. CONCLUSION: This study indicates that the BBR derivatives are hopeful for further exploration as the lead compound with novel antimicrobial agents. © 2024 Society of Chemical Industry.

Association of high fibrinogen to albumin ratio with long-term mortality in patients with spontaneous intracerebral hemorrhage.

Background: The association between fibrinogen-to-albumin ratio (FAR) and in-hospital mortality in patients with spontaneous intracerebral hemorrhage (ICH) has been established. However, the association with long-term mortality in spontaneous ICH remains unclear. This study aims to investigate the association between FAR and long-term mortality in these patients. Methods: Our retrospective study involved 3,538 patients who were diagnosed with ICH at West China Hospital, Sichuan University. All serum fibrinogen and serum albumin samples were collected within 24 h of admission and participants were divided into two groups according to the FAR. We conducted a Cox proportional hazard analysis to evaluate the association between FAR and long-term mortality. Results: Out of a total of 3,538 patients, 364 individuals (10.3%) experienced in-hospital mortality, and 750 patients (21.2%) succumbed within one year. The adjusted hazard ratios (HR) showed significant associations with in-hospital mortality (HR 1.61, 95% CI 1.31-1.99), 1-year mortality (HR 1.45, 95% CI 1.25-1.67), and long-term mortality (HR 1.45, 95% CI 1.28-1.64). Notably, the HR for long-term mortality remained statistically significant at 1.47 (95% CI, 1.15-1.88) even after excluding patients with 1-year mortality. Conclusion: A high admission FAR was significantly correlated with an elevated HR for long-term mortality in patients with ICH. The combined assessment of the ICH score and FAR at admission showed higher predictive accuracy for long-term mortality than using the ICH score in isolation.

Microscopic Mechanism of CO2 Displacement Oil in Different Pore Throat Radius Segments of Tight Sandstone Reservoirs.

The micropore structure of tight sandstone affects the efficiency of CO2 displacement of crude oil. As the pressure changes, the oil displacement efficiency (E d) in segments with different pore radii changes, and the asphaltene precipitation in the pores causes alterations in the pore structure and wettability, which constrain E d. Ten samples of tight sandstone from the Yanchang Formation in the Ordos Basin were selected for this study. A variety of methods, including X-ray diffraction (XRD), casting thin sections (CTS), scanning electron microscopy (SEM), high-pressure mercury intrusion (HPMI), CT scanning, and nuclear magnetic resonance (NMR) combined with CO2 displacement, were used to study the efficiency of crude oil utilization and the amount of asphaltene deposited at different pore-throat radii, and then the impacts of pressure, pore structure, and wettability changes on E d were discussed. The findings indicate that samples have three types: macropore-fine throats (MF), medium pore-tiny throats (MT), and small pore-microthroats (SM). The MT exhibits a favorable configuration. The pore-throat radius of each sample can be divided into two segments, namely, large pore segments (PL) and small pore segments (PS), and the PL has a significant E d. The E d of the MF-type PS is constrained by pressure. The E d of PL is significantly affected by the pressure sensitivity for the MT, while the E d of PL for the SM structure is more affected by pressure. Changes in wettability and the precipitation of asphaltene are the results of the reaction between crude oil and CO2. In the MF, asphaltene precipitates from the PL, while in the MT and SM, asphaltene precipitates both from the PL and PS. The amount of asphaltene precipitation strongly affects the E d in PS. The oil wettability increases more obviously with better pore-throat configurations. This study offers a reference and foundational understanding for evaluating CO2 displacement in tight sandstone reservoirs.

An Ion-Pumping Quasi-Solid Electrolyte Enabled by Electrokinetic Effects for Stable Aqueous Zinc Metal Batteries.

The practical application of aqueous zinc (Zn) metal batteries (ZMBs) is hindered by the complicated hydrogen evolution, passivation reactions, and dendrite growth of Zn metal anodes. Here, an ion-pumping quasi-solid electrolyte (IPQSE) with high Zn2+ transport kinetics enabled by the electrokinetic phenomena to realize high-performance quasi-solid state Zn metal batteries (QSSZMBs) is reported. The IPQSE is prepared through the in situ ring-opening polymerization of tetramethylolmethane-tri-ß-aziridinylpropionate in the aqueous electrolyte. The porous polymer framework with high zeta potential provides the IPQSE with an electrokinetic ion-pumping feature enabled by the electrokinetic effects (electro-osmosis and electrokinetic surface conduction), which significantly accelerates the Zn2+ transport, reduces the concentration polarization and overcomes the diffusion-limited current. Moreover, the Zn2+ affinity of the polymer and hydrogen bonding interactions in the IPQSE changes the Zn2+ coordination environment and reduces the amount of free H2O, which lowers the H2O activity and inhibits H2O-induced side reactions. Consequently, the highly reversible and stable Zn metal anodes are achieved. The assembled QSSZMBs based on the IPQSE display excellent cycling stability with high capacity retention and Coulombic efficiency. The high-performance quasi-solid state Zn metal pouch cells are demonstrated, showing great promise for the practical application of the IPQSE.

Association between Postoperative Decrease of Albumin and Outcomes in Patients Undergoing Craniotomy for Brain Tumors.

BACKGROUND: Serum albumin reflects nutritional status and is associated with postoperative complications and mortality. Delta albumin (ΔAlb), defined as the difference between preoperative and lowest postoperative levels, could predict complications and mortality, even with post-op levels above 30 g/L prompting albumin infusions. This study aimed to assess how ΔAlb relates to outcomes in craniotomy patients with brain tumors. METHODS: This retrospective study screened patients diagnosed with a brain tumor who underwent cerebral surgery from a single Chinese hospital between December 2010 and April 2021. Patients were divided into four groups based on their ΔAlb levels: <5 g/L (normal), 5-9.9 g/L (mild ΔAlb), 10-14.9 g/L (moderate ΔAlb), and ≥15 g/L (severe ΔAlb). The primary outcome was postoperative 30-day mortality. RESULTS: Among the 9660 patients undergoing craniotomy for brain tumors, the median ΔAlb level after craniotomy was 7.3 g/L. ΔAlb was associated with increased postoperative 30-day mortality; Odds ratios (OR) for mild, moderate, and severe ΔAlb were 1.93(95% CI, 1.17-3.18,P=0.01), 2.21(95% CI, 1.28-3.79,P=0.004), and 7.26(95% CI, 4.19-12.58,P<0.01), respectively. Significantly, ΔAlb >5g/L was found to have a strong association with a higher risk of mortality, even when the nadir Alb remained greater than 30 g/L (OR, 1.84; 95% CI, 1.13- 3.00, P=0.014). CONCLUSIONS: Among patients undergoing craniotomy for brain tumor resection, a mild degree of ΔAlb was associated with increased 30-day mortality, even if the nadir Alb remained greater than 30 g/L. Moreover, ΔAlb was associated with postoperative complications and longer lengths of stay.

A pentavalent peptide vaccine elicits Aß and tau antibodies with prophylactic activity in an Alzheimer's disease mouse model.

Amyloid-ß (Aß) and hyperphosphorylated tau protein are targets for Alzheimer's Disease (AD) immunotherapies, which are generally focused on single epitopes within Aß or tau. However, due to the complexity of both Aß and tau in AD pathogenesis, a multipronged approach simultaneously targeting multiple epitopes of both proteins could overcome limitations of monotherapies. Herein, we propose an active AD immunotherapy based on a nanoparticle vaccine comprising two Aß peptides (1-14 and pyroglutamate pE3-14) and three tau peptides (centered on phosphorylated pT181, pT217 and pS396/404). These correspond to both soluble and aggregated targets and are displayed on the surface of immunogenic liposomes in an orientation that maintains reactivity with epitope-specific monoclonal antibodies. Intramuscular immunization of mice with individual epitopes resulted in minimally cross-reactive antibody induction, while simultaneous co-display of 5 antigens ("5-plex") induced antibodies against all epitopes without immune interference. Post-immune sera recognized plaques and neurofibrillary tangles from human AD brain tissue. Vaccine administration to 3xTg-AD mice using a prophylactic dosing schedule inhibited tau and amyloid pathologies and resulted in improved cognitive function. Immunization was well tolerated and did not induce antigen-specific cellular responses or persistent inflammatory responses in the peripheral or central nervous system. Antibody levels could be reversed by halting monthly vaccinations. Altogether, these results indicate that active immune therapies based on nanoparticle formulations of multiple Aß and tau epitopes warrant further study for treating early-stage AD.

Hourly effect of atmospheric reactive nitrogen species on the onset of acute ischemic stroke: Insight from the Shanghai Stroke Service System Database.

Acute ischemic stroke (AIS) is one of the most predominant causes of mortality and disability in China. Significant uncertainties in stroke diagnosis and time of onset have resulted in inconsistent evidence on the association between ambient air pollution and the risk of AIS. The present study aimed to evaluate the impact of air pollution on AIS onset based on high time-resolution air pollution data and a stroke-specific registry across the past five years. Hourly concentrations of PM2.5, PM10, O3, SO2, CO, NO2 and nitrous acid (HONO) were monitored from 2017 to 2021, with which a distributed lag non-linear model and conditional logistic regression models coupled with a time-stratified case-crossover design were applied to 106,623 AIS cases recorded in the Shanghai Stroke Service (4S) database during the study period. Results from the conditional logistic regression models indicate that acute exposure to PM2.5, PM10, SO2, NO2 and HONO was found to be associated with AIS onset, respectively. The corresponding cumulative excessive risks of AIS onset were 0.8 %, 1 %, 2.4 %, 2.1 % and 1.8 % for each interquartile range increase in the respective concentration. The longest lag-effect (up to 13 h) was observed for reactive nitrogen species (RNS), such as NO2 and HONO, which remained robust in two-pollutant models. Similar important role of RNS in AIS onset were confirmed by the distributed lag non-linear model. By demonstrating the transient effect of ambient air pollution on AIS, especially the relationships between RNS and AIS for the first time, our study provides stringent evidence for future mitigation strategies for pollution emission and public health.

Isomangiferin promotes the migration and osteogenic differentiation of rat bone marrow mesenchymal stem cells.

Delayed or failed bone healing is a significant clinical challenge worldwide. Bone marrow mesenchymal stem cells (BMSCs) offer a promising approach for improving fracture healing. Isomangiferin, a xanthone C-glucoside, is known for its pharmacological activities, but its role in fracture healing remains unclear. In this study, we investigated the effects of isomangiferin on BMSCs under oxidative stress conditions induced by hydrogen peroxide (H2O2). Our results showed that isomangiferin promotes osteogenic differentiation and migration of H2O2-treated BMSCs, reduces apoptosis and reactive oxygen species production, and activates the AMP-activated protein kinase/acetyl-CoA carboxylase (AMPK/ACC) pathway. These findings suggest that isomangiferin may be a potential therapeutic agent for enhancing bone healing by modulating BMSC function.

An integrated QTL and RNA-seq analysis revealed new petal morphology loci in Brassica napus L.

BACKGROUND: Rapeseed (Brassica napus L.) is one of the most important oil crops and a wildly cultivated horticultural crop. The petals of B. napus serve to protect the reproductive organs and attract pollinators and tourists. Understanding the genetic basis of petal morphology regulation is necessary for B. napus breeding. RESULTS: In the present study, the quantitative trait locus (QTL) analysis for six B. napus petal morphology parameters in a double haploid (DH) population was conducted across six microenvironments. A total of 243 QTLs and five QTL hotspots were observed, including 232 novel QTLs and three novel QTL hotspots. The spatiotemporal transcriptomic analysis of the diversiform petals was also conducted, which indicated that the expression of plant hormone metabolic and cytoskeletal binding protein genes was variant among diversiform petals. CONCLUSIONS: The integration of QTL and RNA-seq analysis revealed that plant hormones (including cytokinin, auxin, and gibberellin) and cytoskeleton were key regulators of the petal morphology. Subsequently, 61 high-confidence candidate genes of petal morphology regulation were identified, including Bn.SAUR10, Bn.ARF18, Bn.KIR1, Bn.NGA2, Bn.PRF1, and Bn.VLN4. The current study provided novel QTLs and candidate genes for further breeding B. napus varieties with diversiform petals.

Distinct dynamics of parental 5-hydroxymethylcytosine during human preimplantation development regulate early lineage gene expression.

The conversion of DNA 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) by TET enzymes represents a significant epigenetic modification, yet its role in early human embryos remains largely unknown. Here we showed that the early human embryo inherited a significant amount of 5hmCs from an oocyte, which unexpectedly underwent de novo hydroxymethylation during its growth. Furthermore, the generation of 5hmC in the paternal genome after fertilization roughly followed the maternal pattern, which was linked to DNA methylation dynamics and regions of sustained methylation. The 5hmCs persisted until the eight-cell stage and exhibited high enrichment at OTX2 binding sites, whereas knockdown of OTX2 in human embryos compromised the expression of early lineage genes. Specifically, the depletion of 5hmC affected the activation of embryonic genes, which was further evaluated by ectopically expressing mouse Tet3 in human early embryos. These findings revealed distinct dynamics of 5hmC and unravelled its multifaceted functions in early human embryonic development.

Exhaustive State-to-State Cross Sections and Rate Coefficients for Inelastic N2-N2 Collisions using QCT Combined with Neural Network Models.

Using the quasi-classical trajectory method, we systematically studied the state-to-state vibrational relaxation process of N2(v1) + N2(v2) collisions over a wide temperature range (5000-30,000 K). Different temperature dependencies of the single- and multiquantum VV and VT events in various (v1,v2) collisions are captured, with the dominant channel being related to the initial vibrational energy levels (vmax = 50). At a specified relative translational energy, there is a monotonic relationship of the VT cross sections with the vibrational energy level, particularly in high-energy collisions. Additionally, we constructed well-trained neural network models (R-values reaching 0.99) using limited quasi-classical trajectory (QCT) data sets, which can be used to predict the state-to-state cross sections and rate coefficients of the VV processes N2(v1) + N2(v2) → N2(v1 - Δv) + N2(v2 + Δv) and VT processes N2(v1) + N2(v2) → N2(v1 - Δv) + N2(v2) (Δv = ±1, ±2, ±3) for collisions with arbitrary initial vibrational states. This work not only significantly reduces computational resources but also serves as a reference for the study of the state-to-state dynamics of all four-atom collision systems in hypersonic flows.

A Rare Case of Follicular Dendritic Cell Tumor of the Abdominal Cavity Visualized by 18F-AlF-NOTA-Octreotide PET/CT.

ABSTRACT: Positivity of follicular dendritic cell tumor in somatostatin receptor imaging is rare. A 68-year-old woman underwent ultrasound in health examination. The results showed abnormal echoes in the pancreatic head region, suggestive of a neuroendocrine tumor of the pancreatic head. 18F-AlF-NOTA-octreotide PET/CT was performed for staging. 18F-AlF-NOTA-octreotide PET/CT revealed an irregular mass between the caudate lobe of the liver and the pancreatic head with heterogeneously increased uptake, which was later confirmed as follicular dendritic cell tumor by pathological examination.

Exploring ischemic core growth rate and endovascular therapy benefit in large core patients.

After stroke onset, ischemic brain tissue will progress to infarction unless blood flow is restored. Core growth rate measures the infarction speed from stroke onset. This multicenter cohort study aimed to explore whether core growth rate influences benefit from the reperfusion treatment of endovascular thrombectomy in large ischemic core stroke patients. It identified 134 patients with large core volume >70 mL assessed on brain perfusion image within 9 hours of stroke onset. Of 134 patients, 71 received endovascular thrombectomy and 63 did not receive the treatment. Overall, poor outcomes were frequent, with 3-month severed disability or death rate at 56% in treatment group and 68% in no treatment group (p = 0.156). Patients were then stratified by core growth rate. For patients with 'ultrafast core growth' of >70 mL/hour, rates of poor outcome were especially high in patients without endovascular thrombectomy (n = 13/14, 93%) and relatively lower in patients received the treatment (n = 12/20, 60%, p = 0.033). In contrast, for patients with core growth rate <70 mL/hour, there was not a large difference in poor outcomes between patients with and without the treatment (55% vs. 61%, p = 0.522). Therefore, patients with 'ultrafast core growth' might stand to benefit the most from endovascular treatment.

Molecular Editing of Pyrroles to Benzenes/Naphthalenes by N2O Deletion.

Molecular editing promises to facilitate the rapid diversification of complex molecular architectures by rapidly and conveniently altering core frameworks. This approach has the potential to accelerate both drug discovery and total synthesis. In this study, we present a novel protocol for the molecular editing of pyrroles. Initially, N-Boc pyrroles and alkynes are converted into N-bridged compounds through a Diels-Alder reaction. These compounds then undergo deprotection of the Boc group, nitrosylation, and cheletropic N2O extrusion to yield benzene or naphthalene products. By using benzyne as a substrate, this method can be conceptually viewed as a fusion of skeletal editing of the pyrrole ring and site-selective peripheral editing of the benzene ring. Furthermore, this proof-of-concept protocol has demonstrated its potential to transform the (hetero)arene motif from commercially available drugs, offering the possibility of generating new biologically active compounds.

Screening for compounds with bioaccumulation potential in breast milk using their retention behavior in two-dimensional gas chromatography.

Discovery of emerging pollutants in breast milk will be helpful for understanding the hazards to human health. However, it is difficult to identify key compounds among thousands present in complex samples. In this study, a method for screening compounds with bioaccumulation potential was developed. The method can decrease the number of compounds needing structural identification because the partitioning properties of bioaccumulative compounds can be mapped onto GC×GC chromatograms through their retention behaviors. Twenty pooled samples from seven provinces in China were analyzed. 1,286 compounds with bioaccumulation potential were selected from over 3,000 compounds. Sixty-two compounds, including aromatic compounds, phthalates, and phenolics etc., were identified with a high level of confidence and then quantified. Among them, twenty-seven compounds were found for the first time in breast milk. Three phthalate plasticizers and two phenolic antioxidants were found in significantly higher concentrations than other compounds. A toxicological priority index approach was applied to prioritize the compounds considering their concentrations, detection frequencies and eight toxic effects. The prioritization indicated that 13 compounds, including bis(2-ethylhexyl) phthalate, dibutyl phthalate, 1,3-di-tert-butylbenzene, phenanthrene, 2,6-di-tert-butyl-1,4-benzoquinone, 2,4-di-tert-butylphenol, and others, showed higher health risks. Meanwhile, some compounds with high risk for a particular toxic effect, such as benzothiazole and geranylacetone, were still noteworthy. This study is important for assessing the risks of human exposure to organic compounds.