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1.
Nat Commun ; 15(1): 4793, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38839767

RESUMO

Chiral amides are important structure in many natural products and pharmaceuticals, yet their efficient synthesis from simple amide feedstock remains challenge due to its weak Lewis basicity. Herein, we describe our study of the enantioselective synthesis of chiral amides by N-alkylation of primary amides taking advantage of an achiral rhodium and chiral squaramide co-catalyzed carbene N-H insertion reaction. This method features mild condition, rapid reaction rate (in all cases 1 min) and a wide substrate scope with high yield and excellent enantioselectivity. Further product transformations show the synthetic potential of this reaction. Mechanistic studies reveal that the non-covalent interactions between the catalyst and reaction intermediate play a critical role in enantiocontrol.

2.
Nat Struct Mol Biol ; 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38918638

RESUMO

Epigenetic regulators have a crucial effect on gene expression based on their manipulation of histone modifications. Histone H2AK119 monoubiquitination (H2AK119Ub), a well-established hallmark in transcription repression, is dynamically regulated by the opposing activities of Polycomb repressive complex 1 (PRC1) and nucleosome deubiquitinases including the primary human USP16 and Polycomb repressive deubiquitinase (PR-DUB) complex. Recently, the catalytic mechanism for the multi-subunit PR-DUB complex has been described, but how the single-subunit USP16 recognizes the H2AK119Ub nucleosome and cleaves the ubiquitin (Ub) remains unknown. Here we report the cryo-EM structure of USP16-H2AK119Ub nucleosome complex, which unveils a fundamentally distinct mode of H2AK119Ub deubiquitination compared to PR-DUB, encompassing the nucleosome recognition pattern independent of the H2A-H2B acidic patch and the conformational heterogeneity in the Ub motif and the histone H2A C-terminal tail. Our work highlights the mechanism diversity of H2AK119Ub deubiquitination and provides a structural framework for understanding the disease-causing mutations of USP16.

3.
Aging Dis ; 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38916727

RESUMO

Endogenous retroviruses (ERVs), a subset of genomic transposable elements (TEs) in a broader sense, have remained latent within mammalian genomes for tens of millions of years. These genetic elements are typically in a silenced state due to stringent regulatory mechanisms. However, under specific conditions, they can become activated, triggering inflammatory responses through diverse mechanisms. This activation has been shown to play a potential role in various neurological disorders, tumors, and cellular senescence. Consequently, the regulation of ERV expression through various methods holds promise for clinical applications in disease treatment. ERVs also engage in interactions with a variety of exogenous viruses, thereby influencing the outcomes of viral infectious diseases. This article comprehensively reviews the pathogenic cascade of ERVs, encompassing activation, inflammation, associated diseases, senescence, and interplay with viruses. Additionally, it outlines therapeutic strategies targeting ERVs with the aim of offering novel research directions for understanding the relationship between ERVs and diseases, along with corresponding treatment modalities.

4.
Front Pharmacol ; 15: 1284371, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38881872

RESUMO

Background: Cynanchum paniculatum (Bunge) Kitag. ex H.Hara, a member of the Asclepiadaceae family, has a rich history as a traditional Chinese medicinal plant used to treat digestive disorders. However, its potential anti-cancer effects in pancreatic cancer remain largely unexplored. Aim: This study delves into the intricate anti-pancreatic cancer mechanisms of C. paniculatum (Bunge) Kitag. ex H.Hara aqueous extract (CPAE) by elucidating its role in apoptosis induction and the inhibition of invasion and migration. Methods: A comprehensive set of methodologies was employed to assess CPAE's impact, including cell viability analyses using MTT and colony formation assays, flow cytometry for cell cycle distribution and apoptosis assessment, scratch-wound and Matrigel invasion assays for migration and invasion capabilities, and immunoblotting to measure the expression levels of key proteins involved in apoptosis and metastasis. Additionally, a murine xenograft model was established to investigate CPAE's in vivo anti-cancer potential. Results: CPAE exhibited time- and dose-dependent suppression of proliferation and colony formation in pancreatic cancer cells. Notably, CPAE induced apoptosis and G2/M phase arrest, effectively activating the caspase-dependent PARP pathway. At non-cytotoxic doses, CPAE significantly curtailed the metastatic abilities of pancreatic cells, effectively suppressing epithelial-mesenchymal transition (EMT) and downregulating the TGF-ß1/Smad2/3 pathway. In vivo experiments underscored CPAE's ability to inhibit tumor proliferation. Conclusion: This study illuminates the multifaceted anti-proliferative, pro-apoptotic, anti-invasive, and anti-migratory effects of CPAE, both in vitro and in vivo. CPAE emerges as a promising herbal medicine for pancreatic cancer treatment, with its potential mediated through apoptosis induction via the caspase-dependent PARP pathway and MET suppression via the TGF-ß1/Smad2/3 signaling pathway at non-cytotoxic doses. These findings advocate for further exploration of CPAE's therapeutic potential in pancreatic cancer.

5.
ACS Omega ; 9(23): 24406-24414, 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38882071

RESUMO

A highly enantioselective 1,3-dipolar cycloaddition of ethoxyformylmethylene oxindole with iminoesters has been achieved using the Cu(I)-(S,Sp)-Ph Phosferrox catalytic system, generating a series of chiral spiro[pyrrolidin-3,3'-oxindole] compounds with four consecutive stereocenters, including a spirocycle quaternary center (71%-99% yield, up to >20:1 dr and 95:5 er). The compounds exhibited good inhibitory activity against Valsa mali (V.m.), Fusarium oxysporium (F.o.), and Alternaria brassicae (A.b.).

6.
Nat Commun ; 15(1): 4668, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38821945

RESUMO

Robotic surgery may be an alternative to laparoscopic surgery for gastric cancer (GC). However, randomized controlled trials (RCTs) reporting the differences in survival between these two approaches are currently lacking. From September 2017 to January 2020, 300 patients with cT1-4a and N0/+ were enrolled and randomized to either the robotic (RDG) or laparoscopic distal gastrectomy (LDG) group (NCT03313700). The primary endpoint was 3-year disease-free survival (DFS); secondary endpoints reported here are the 3-year overall survival (OS) and recurrence patterns. The remaining secondary outcomes include intraoperative outcomes, postoperative recovery, quality of lymphadenectomy, and cost differences, which have previously been reported. There were 283 patients in the modified intention-to-treat analysis (RDG group: n = 141; LDG group: n = 142). The trial has met pre-specified endpoints. The 3-year DFS rates were 85.8% and 73.2% in the RDG and LDG groups, respectively (p = 0.011). Multivariable Cox regression model including age, tumor size, sex, ECOG PS, lymphovascular invasion, histology, pT stage, and pN stage showed that RDG was associated with better 3-year DFS (HR: 0.541; 95% CI: 0.314-0.932). The RDG also improved the 3-year cumulative recurrence rate (RDG vs. LDG: 12.1% vs. 21.1%; HR: 0.546, 95% CI: 0.302-0.990). Compared to LDG, RDG demonstrated non-inferiority in 3-year DFS rate.


Assuntos
Gastrectomia , Laparoscopia , Procedimentos Cirúrgicos Robóticos , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/cirurgia , Neoplasias Gástricas/patologia , Neoplasias Gástricas/mortalidade , Gastrectomia/métodos , Laparoscopia/métodos , Masculino , Feminino , Procedimentos Cirúrgicos Robóticos/métodos , Pessoa de Meia-Idade , Idoso , Excisão de Linfonodo/métodos , Intervalo Livre de Doença , Resultado do Tratamento , Recidiva Local de Neoplasia , Adulto
7.
Cell Rep Med ; 5(5): 101573, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38776874

RESUMO

Epstein-Barr virus (EBV) is linked to various malignancies and autoimmune diseases, posing a significant global health challenge due to the lack of specific treatments or vaccines. Despite its crucial role in EBV infection in B cells, the mechanisms of the glycoprotein gp42 remain elusive. In this study, we construct an antibody phage library from 100 EBV-positive individuals, leading to the identification of two human monoclonal antibodies, 2B7 and 2C1. These antibodies effectively neutralize EBV infection in vitro and in vivo while preserving gp42's interaction with the human leukocyte antigen class II (HLA-II) receptor. Structural analysis unveils their distinct binding epitopes on gp42, different from the HLA-II binding site. Furthermore, both 2B7 and 2C1 demonstrate potent neutralization of EBV infection in HLA-II-positive epithelial cells, expanding our understanding of gp42's role. Overall, this study introduces two human anti-gp42 antibodies with potential implications for developing EBV vaccines targeting gp42 epitopes, addressing a critical gap in EBV research.


Assuntos
Anticorpos Monoclonais , Epitopos , Infecções por Vírus Epstein-Barr , Herpesvirus Humano 4 , Humanos , Herpesvirus Humano 4/imunologia , Infecções por Vírus Epstein-Barr/imunologia , Infecções por Vírus Epstein-Barr/virologia , Anticorpos Monoclonais/imunologia , Epitopos/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Camundongos , Antígenos de Histocompatibilidade Classe II/imunologia , Antígenos de Histocompatibilidade Classe II/metabolismo , Proteínas Virais/imunologia , Linfócitos B/imunologia
8.
Zhongguo Zhong Yao Za Zhi ; 49(7): 1717-1724, 2024 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-38812184

RESUMO

Panax ginseng, known as the "king of herbs", is a highly valued medicinal plant, and its medicinal parts include roots, stems, leaves, flowers, and fruits, among which the roots are the most commonly used. The main active components of this medicinal plant include triterpenoid saponins, polysaccharides, peptides, and volatile oils. The chemical components and active metabolites endow this herb with a variety of pharmacological effects, and thus this herb is used to treat various diseases and play healthcare roles. Currently, a wide range of preparations of P. ginseng have been officially registered and marketed, including tablets, oral liquids, and injections, which demonstrate good clinical efficacy in regulating immunity, adjuvant treatment of tumors, alleviating fatigue, delaying the aging process, improving glucose and lipid metabolism, treating cardiovascular diseases, and relieving inflammation and pain. The production process and quality standards of these drugs are of great significance to ensure their efficacy. According to the theory that Ginseng Radix et Rhizoma can greatly replenish original Qi, tonify the spleen and lung, promote fluid production to quench thirst, tranquilize mind and enrich the intelligence, this paper systematically summarized the clinical application progress of P. ginseng and rela-ted preparations on the market and prospected the further development of preparations from P. ginseng, providing a reference for further exploring the medicinal value and healthcare function of this herb. The above contents, as an important basis for the in-depth development of P. ginseng and related drugs, increase the possibilities for the application of P. ginseng.


Assuntos
Medicamentos de Ervas Chinesas , Panax , Panax/química , Humanos , Medicamentos de Ervas Chinesas/química , Animais
9.
J Steroid Biochem Mol Biol ; 243: 106543, 2024 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-38740074

RESUMO

A significant reduction in plasma concentration of cholesterol during early lactation is a common occurrence in high-yielding dairy cows. An insufficient synthesis of cholesterol in the liver has been linked to lipid accumulation caused by high concentrations of fatty acids during negative energy balance (NEB). As ruminant diets do not provide quantitative amounts of cholesterol for absorption, phytosterols such as ß-sitosterol may serve to mitigate the shortfall in cholesterol within the liver during NEB. To gain mechanistic insights, primary hepatocytes were isolated from healthy female 1-day old calves for in vitro studies with or without 1.2 mM fatty acids (FA) to induce metabolic stress. Furthermore, hepatocytes were treated with 50 µM ß-sitosterol with or without FA. Data were analyzed by one-way ANOVA with subsequent Bonferroni correction. Results revealed that calf hepatocytes treated with FA had greater content of non-esterified fatty acids (NEFA) and triacylglycerol (TAG), and greater mRNA and protein abundance of the lipid synthesis-related SREBF1 and FASN. In contrast, mRNA and protein of CPT1A (fatty acid oxidation) and the cholesterol metabolism-related targets SREBF2, HMGCR, ACAT2, APOA1, ABCA1 and ABCG5 was lower. Content of the antioxidant-related glutathione (GSH) and activities of superoxide dismutase (SOD) also was lower. Compared with FA challenge alone, 50 µM ß-sitosterol led to greater mRNA and protein abundance of SREBF2, HMGCR, ACAT2 and ABCG5, and greater content of GSH and activity of SOD. In contrast, compared with the FA group, the mRNA and protein abundance of SREBF1 and ACC1 and the content of TAG and NEFA in the ß-sitosterol + FA group were lower. Overall, ß-sitosterol can promote cholesterol metabolism and reduce oxidative stress while reducing lipid accumulation in hepatocytes challenged with high concentrations of fatty acids.

10.
Lancet Microbe ; 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38735303

RESUMO

Drug development for tuberculosis is hindered by the methodological limitations in the definitions of patient outcomes, particularly the slow organism growth and difficulty in obtaining suitable and representative samples throughout the treatment. We developed target product profiles for biomarker assays suitable for early-phase and late-phase clinical drug trials by consulting subject-matter experts on the desirable performance and operational characteristics of such assays for monitoring of tuberculosis treatment in drug trials. Minimal and optimal criteria were defined for scope, intended use, pricing, performance, and operational characteristics of the biomarkers. Early-stage trial assays should accurately quantify the number of viable bacilli, whereas late-stage trial assays should match the number, predict relapse-free cure, and replace culture conversion endpoints. The operational criteria reflect the infrastructure and resources available for drug trials. The effective tools should define the sterilising activity of the drug and lower the probability of treatment failure or relapse in people with tuberculosis. The target product profiles outlined in this Review should guide and de-risk the development of biomarker-based assays suitable for phase 2 and 3 clinical drug trials.

11.
Exp Anim ; 2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38797667

RESUMO

Ischemia/reperfusion (I/R) is a pathological process that occurs in numerous organs and is often associated with severe cellular damage and death. Ectodysplasin-A2 receptor (EDA2R) is a member of the TNF receptor family that has anti-inflammatory and antioxidant effects. However, to the best of our knowledge, its role in the progression of myocardial I/R injury remains unclear. The present study aimed to investigate the role of EDA2R during myocardial I/R injury and the molecular mechanisms involved. In vitro, dexmedetomidine (DEX) exhibited a protective effect on hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury and downregulated EDA2R expression. Subsequently, EDA2R silencing enhanced cell viability and reduced the apoptosis of cardiomyocytes. Furthermore, knockdown of EDA2R led to an elevated mitochondrial membrane potential (MMP), repressed the release of Cytochrome C and upregulated Bcl-2 expression. EDA2R knockdown also resulted in downregulated expression of Bax, and decreased activity of Caspase-3 and Caspase-9 in cardiomyocytes, reversing the effects of H/R on mitochondria-mediated apoptosis. In addition, knockdown of EDA2R suppressed H/R-induced oxidative stress. Mechanistically, EDA2R knockdown inactivated the NF-κB signaling pathway. Additionally, downregulation of EDA2R weakened myocardial I/R injury in mice, as reflected by improved left ventricular function and reduced infarct size, as well as suppressed apoptosis and oxidative stress. Additionally, EDA2R knockdown repressed the activation of NF-κB signal in vivo. Collectively, knockdown of EDA2R exerted anti-apoptotic and antioxidant effects against I/R injury in vivo and in vitro by suppressing the NF-κB signaling pathway.

12.
JAMA Surg ; 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38691353

RESUMO

Importance: Splenic hilar lymphadenectomy has been recommended for locally advanced proximal gastric cancer (APGC) involving the greater curvature. However, it is unclear whether laparoscopic spleen-preserving splenic hilar lymphadenectomy (LSPSHL) is associated with a long-term survival benefit for APGC without greater curvature invasion. Objective: To present the 5-year follow-up data from a randomized clinical trial that compared laparoscopic total gastrectomy (D2 group) with D2 plus LSPSHL (D2 + No. 10 group) among patients with resectable APGC. Design, Setting, and Participants: This is a post hoc secondary analysis of a randomized clinical trial that enrolled 536 patients with potentially resectable APGC (cT2-4a, N0 or N+, and M0) without greater curvature invasion from January 5, 2015, to October 10, 2018. All patients were tracked for at least 5 years. The final follow-up was on October 30, 2023. Interventions: Patients were randomly assigned in a 1:1 ratio to the D2 + No. 10 or D2 groups. Main Outcomes and Measures: The 5-year disease-free survival (DFS) and overall survival (OS) rates were measured. Recurrence patterns and causes of death were compared. Results: A total of 526 patients (392 men [74.5%]; mean [SD] age, 60.6 [9.6] years) were included in the modified intent-to-treat analysis, with 263 patients in each group. The 5-year DFS rate was 63.9% (95% CI, 58.1%-69.7%) for the D2 + No. 10 group and 55.1% (95% CI, 49.1%-61.1%) for the D2 group (log-rank P = .04). A statistically significant difference was observed in the 5-year OS between the D2 + No. 10 group and the D2 group (66.2% [95% CI, 60.4%-71.9%] vs 57.4% [95% CI, 51.4%-63.4%]; log-rank P = .03). The No. 10 lymph node exhibited a therapeutic value index (TVI) of 6.5, surpassing that of Nos. 8a (TVI, 3.0), 11 (TVI, 5.8), and 12a (TVI, 0.8). A total of 86 patients in the D2 + No. 10 group (cumulative incidence, 32.7%) and 111 patients in the D2 group (cumulative incidence, 42.2%) experienced recurrence (hazard ratio, 0.72; 95% CI, 0.54-0.95; P = .02). The multivariable competing risk regression model demonstrated that D2 + No. 10 remained an independent protective factor for a lower 5-year cumulative recurrence rate after surgery (hazard ratio, 0.75; 95% CI, 0.56-1.00; P = .05). There was a significant difference in the 5-year cumulative recurrence rate at the No. 10 lymph node area between the 2 groups (D2 + No. 10 group vs D2 group: 0% vs 2.3% [n = 6]; P = .01). Conclusions: This post hoc secondary analysis of a randomized clinical trial found that laparoscopic total gastrectomy with LSPSHL can improve the prognosis and reduce recurrence for APGC without greater curvature invasion. Future multicenter studies are warranted to validate these findings. Trial Registration: ClinicalTrials.gov Identifier: NCT02333721.

13.
Int J Surg ; 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38775618

RESUMO

BACKGROUND: Learning curves have been used in the field of RG. However, it should be noted that the previous study did not comprehensively investigate all changes related to the learning curve.This study aims to establish a learning curve for radical robotic gastrectomy (RG) and evaluate its effect on the short-term outcomes of patients with gastric cancer. METHODS: The clinicopathological data of 527 patients who underwent RG between August 2016 and June 2021 were retrospectively analyzed. Learning curves related to the operation time and postoperative hospital stay were determined separately using cumulative sum (CUSUM) analysis. Then, the impact of the learning curve on surgical efficacy was analyzed. RESULTS: Combining the CUSUM curve break points and technical optimization time points, the entire cohort was divided into three phases (patients 1-100, 101-250, and 251-527). The postoperative complication rate and postoperative recovery time tended to decrease significantly with phase advancement (P<0.05). More extraperigastric examined lymph nodes (LN) were retrieved in phase III than in phase I (I vs. III, 15.12±6.90 vs. 17.40±7.05, P=0.005). The rate of LN noncompliance decreased with phase advancement. Textbook outcome (TO) analysis showed that the learning phase was an independent factor in TO attainment (P<0.05). CONCLUSION: With learning phase advancement, the short-term outcomes were significantly improved. It is possible that our optimization of surgical procedures could have contributed to this improvement. The findings of this study facilitate the safe dissemination of RG in the minimally invasive era.

14.
Theranostics ; 14(7): 2915-2933, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38773976

RESUMO

Background: Pyroptosis plays a crucial role in immune responses. However, the effects of pyroptosis on tumor microenvironment remodeling and immunotherapy in gastric cancer (GC) remain unclear. Patients and Methods: Large-sample GEO data (GSE15459, GSE54129, and GSE62254) were used to explore the immunoregulatory roles of pyroptosis. TCGA cohort was used to elucidate multiple molecular events associated with pyroptosis, and a pyroptosis risk score (PRS) was constructed. The prognostic performance of the PRS was validated using postoperative GC samples from three public databases (n=925) and four independent Chinese medical cohorts (n=978). Single-cell sequencing and multiplex immunofluorescence were used to elucidate the immune cell infiltration landscape associated with PRS. Patients with GC who received neoadjuvant immunotherapy (n=48) and those with GC who received neoadjuvant chemotherapy (n=49) were enrolled to explore the value of PRS in neoadjuvant immunotherapy. Results: GC pyroptosis participates in immune activation in the tumor microenvironment and plays a powerful role in immune regulation. PRS, composed of four pyroptosis-related differentially expressed genes (BATF2, PTPRJ, RGS1, and VCAN), is a reliable and independent biomarker for GC. PRSlow is associated with an activated pyroptosis pathway and greater infiltration of anti-tumor immune cells, including more effector and CD4+ T cells, and with the polarization of tumor-associated macrophages in the tumor center. Importantly, PRSlow marks the effectiveness of neoadjuvant immunotherapy and enables screening of GC patients with combined positive score ≥1 who benefit from neoadjuvant immunotherapy. Conclusion: Our study demonstrated that pyroptosis activates immune processes in the tumor microenvironment. A low PRS correlates with enhanced infiltration of anti-tumor immune cells at the tumor site, increased pyroptotic activity, and improved patient outcomes. The constructed PRS can be used as an effective quantitative tool for pyroptosis analysis to guide more effective immunotherapeutic strategies for patients with GC.


Assuntos
Imunoterapia , Terapia Neoadjuvante , Piroptose , Neoplasias Gástricas , Microambiente Tumoral , Humanos , Neoplasias Gástricas/imunologia , Neoplasias Gástricas/terapia , Neoplasias Gástricas/patologia , Terapia Neoadjuvante/métodos , Microambiente Tumoral/imunologia , Imunoterapia/métodos , Masculino , Prognóstico , Feminino , Biomarcadores Tumorais/metabolismo , Pessoa de Meia-Idade , Regulação Neoplásica da Expressão Gênica , Multiômica
15.
Sci Total Environ ; 934: 172940, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38701921

RESUMO

This study aims to identify unique signatures from residential coal combustion in China across various combustion conditions and coal types. Using a Thermal/Spectral Carbon Analyzer with a Photoionization Time-of-Flight Mass Spectrometer (TSCA-PI-TOF-MS), we focus on the optical properties and organic mass spectra of the emissions. Bituminous coal emerged as the primary emitter of total carbon, releasing 729 µg C/mg PM2.5 under smoldering and 894 µg C/mg PM2.5 under flaming. Carbon fractions mainly comprised OC1 and OC2, except for anthracite's dominance of EC1 under smoldering. Pyrolysis carbon absorption shifted from 405, 445 and 532 nm during smoldering to near-infrared bands (635-980 nm) during flaming for both bituminous and anthracite coal. Conversely, clean coal exhibited an inverse trend, attributed to additives enhancing oxygen-containing organic compounds and long-chain hydrocarbons released in charring process. Sample of bituminous coal began charring at OC3 step, while anthracite began earlier at OC2 step, particularly pronounced under flaming. Clean coal displayed unconventional charring at OC1 step under smoldering condition, producing signature compounds like butenal, methylfuran, furanylalcohol, and naphthol. The mass spectra of bituminous coal featured characteristic peaks, including m/z 192 (methylphenanthrene), 206, 220 (alkylated phenanthrenes), and 234 (retene). Anthracite coal showed a potential tracer at m/z 223, shifting from OC1 in smoldering to OC2 in flaming. Clean coal under flaming condition exhibited elevated levels of aromatic compounds, indicating potential toxicity, with peaks at m/z 178 (phenanthrene), 228 (chrysene/benz[a]anthracene), 234 (retene), 242 (methylchrysene), and 252 (benzo[a]pyrene, benzo[k]fluoranthene). Results also showed that the broader mass spectra range in the OC3 and OC4 steps across all coal types suggests that high-temperature pyrolysis promotes diversity. These findings contribute to refined source apportionment of carbon emissions from residential coal combustion and provide the scientific basis for the formulation of air pollution prevention strategies, crucial for coal-dependent regions.

16.
Talanta ; 277: 126327, 2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38805944

RESUMO

Single photon ionization time-of-flight mass spectrometry (SPI-TOF-MS) is a powerful analytical technique for real-time detection of trace VOCs. However, efficient ion transmission within the ionization chamber has always been a challenging issue in SPI-TOF-MS. In this study, a novel ion guide termed the Segmented Focus Quadrupole Ion Guide (SFQ-IG) was introduced for SPI-TOF-MS. The SFQ-IG device consists of 12 printed circuit boards (PCB), each containing four quarter-ring electrodes with inner diameters progressively decreasing from 26 to 4 mm. The simulation results demonstrated that SFQ-IG exhibited superior ion transmission efficiency than both ion funnel (IF) field and direct current-only (DC-only) field. By integrating into a SPI-TOF-MS, this ion guide was optimized in terms of the ionization source pressure, direct current gradient, and radio frequency amplitude. Further comparative experiments demonstrated that the SPI-TOF-MS with the SFQ-IG exhibited higher sensitivity than both the IF field (1.3-7.4 times) and DC-only field (3.5-8.8 times) for the test VOCs. The improvements in limit of detection (LOD) with the SFQ-IG ranged from 1.6 to 5.3 times compared to the DC-only field for the test VOCs. Fabricated using PCB technology, the SFQ-IG is characterized by its cost-effectiveness, compact size, and high transmission efficiency, facilitating its integration into other mass spectrometers.

17.
J Cardiothorac Surg ; 19(1): 274, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38702789

RESUMO

BACKGROUND: To evaluate the clinical efficacy and safety of intraoperative intravenous amiodarone for arrhythmia prevention in on-pump coronary artery bypass grafting (CABG) patients. METHODS: A meta-analysis of randomized controlled trials was conducted. Pubmed, Embase, Cochrane Library, Ovid, China National Knowledge Infrastructure, and the Wan Fang database until July 1th, 2023. The primary outcomes of interest included the incidences of intra- and post-operative atrial fibrillation (POAF), ventricular fibrillation, or any arrhythmia, including atrial fibrillation, ventricular fibrillation, ventricular tachycardia, premature ventricular contraction, and sinus bradycardia. For continuous and dichotomous variables, treatment effects were calculated as the weighted mean difference (WMD)/risk ratio (RR) and 95% confidence interval (CI). RESULTS: A database search yielded 7 randomized controlled trials including 608 patients, where three studies, including three treatments (amiodarone, lidocaine, and saline), contributed to the clinical outcome of atrial fibrillation, ventricular fibrillation, or any arrhythmia. Meta-analysis demonstrated that amiodarone can significantly reduce the incidence of POAF (RR, 0.39; 95%CI: 0.20, 0.77; P = 0.007, I2 = 0%) in patients undergoing on-pump CABG; there was no statistically significant influence on intra-operative atrial fibrillation, intra- and post-operative ventricular fibrillation, or any arrhythmia. CONCLUSIONS: The current study suggests that intraoperative administration of intravenous amiodarone may be safe and effective in preventing POAF in patients undergoing on-pump CABG. More well-designed clinical trials are needed to validate this result.


Assuntos
Amiodarona , Antiarrítmicos , Ponte de Artéria Coronária , Humanos , Amiodarona/administração & dosagem , Amiodarona/efeitos adversos , Ponte de Artéria Coronária/efeitos adversos , Antiarrítmicos/administração & dosagem , Antiarrítmicos/efeitos adversos , Antiarrítmicos/uso terapêutico , Arritmias Cardíacas/prevenção & controle , Cuidados Intraoperatórios/métodos , Administração Intravenosa , Complicações Pós-Operatórias/prevenção & controle , Resultado do Tratamento , Ensaios Clínicos Controlados Aleatórios como Assunto
18.
Sci Total Environ ; 930: 172786, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38677417

RESUMO

Saline soils are widely distributed in arid areas but there is a lack of mechanistic understanding on the effect of salinity on the formation and biochemical composition of soil organic carbon (SOC). We investigated the effects of salinity on the accumulation of microbial necromass under natural vegetation and in cropland in salt-affected arid areas stretching over a 1200-km transect in northwest China. Under both natural vegetation and cropland, microbial physiological activity (indicated by microbial biomass carbon normalized enzymatic activity) decreased sharply where the electrical conductivity approached 4 ds m-1 (a threshold to distinguish between saline and non-saline soils), but microbial biomass was only slightly affected by salinity. These indicated that a larger proportion of microbes could be inactive or dormant in saline soils. The contribution of fungal necromass C to SOC decreased but the contribution of bacterial necromass C to the SOC increased with increasing soil salinity. Adding fungal and bacterial necromass C together, the contribution of microbial necromass C to SOC in saline soils was 32-39 % smaller compared with non-saline soils. Fungal necromass C took up 85-86 % of microbial necromass C in non-saline soils but this proportion dropped to 60-66 % in saline soils. We suggested that the activity, growth, and turnover rate of microbes slowed by salinity was responsible for the decreased accumulation of fungal necromass in saline compared with non-saline soils, while the increased accumulation of bacterial residue in saline soils could be induced mainly by its slower decomposition. Soil microbial biomass was a poor predictor for the accumulation of microbial necromass in saline soils. We demonstrated a reduced contribution of microbial necromass to SOC and a shift in its composition towards the increase in bacterial origin in saline relative to non-saline soils. We concluded that salinity profoundly changes the biochemistry of SOC in arid regions.


Assuntos
Carbono , Salinidade , Microbiologia do Solo , Solo , Solo/química , Carbono/metabolismo , Carbono/análise , China , Fungos , Clima Desértico , Bactérias/metabolismo , Biomassa
19.
Anal Chim Acta ; 1304: 342531, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38637047

RESUMO

BACKGROUND: The global release of organic and heavy metal components into natural water bodies is a major concern for the environment and human health. The assessment of water quality relies on analyzing organic and heavy metal components qualitatively and quantitatively. Real-time identification of organic and metal components in water systems requires different analytical techniques due to varying measurement requirements. Thus, on-line detecting both organic compounds and heavy metals in ambient water systems simultaneously using a single instrumentation setup presents a significant challenge. RESULTS: In this study, an analytical technique of nebulization-assisted injection plasma ionization mass spectrometry (NI-PIMS) was developed. This novel method enables the simultaneous detection of heavy metals and organic compounds in water system with high sensitivity, which has been demonstrated by the limit of quantification (LOQ) values below 1.0 µg/L for the three sterols (Enrofloxacin, ciprofloxacin, and clenbuterol) and three heavy metals (Pb, Ba, and Cd). Moreover, the method was successfully applied to rapidly analyze real water samples from urban and rural areas in China. The analytical results are available in less than 0.5 min, and only a few microliters of sample are required for each analysis. SIGNIFICANCE AND NOVELTY: As far as we know, this is the first report of on-line simultaneous analysis of organic compounds and heavy metals in a water system using a single mass spectrometry instrument. Compared to traditional methods, NI-PIMS demonstrates higher efficiency, sensitivity, no or lower sample preparation, and less sample consumption. The advancement and widespread use of this technology are expected to enhance the effectiveness of mass spectrometers, broaden the applications, and play an important role in complex sample analysis in fields such as atmospheric science, environmental science, and earth science.

20.
J Am Chem Soc ; 146(15): 10857-10867, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38587540

RESUMO

The asymmetric cross-coupling of unsaturated bonds, hampered by their comparable polarity and reactivity, as well as the scarcity of efficient catalytic systems capable of diastereo- and enantiocontrol, presents a significant hurdle in organic synthesis. In this study, we introduce a highly adaptable photochemical cobalt catalysis framework that facilitates chemo- and stereoselective reductive cross-couplings between common aldehydes with a broad array of carbonyl and iminyl compounds, including N-acylhydrazones, aryl ketones, aldehydes, and α-keto esters. Our methodology hinges on a synergistic mechanism driven by photoredox-induced single-electron reduction and subsequent radical-radical coupling, all precisely guided by a chiral cobalt catalyst. Various optically enriched ß-amino alcohols and unsymmetrical 1,2-diol derivatives (80 examples) have been synthesized with good yields (up to 90% yield) and high stereoselectivities (up to >20:1 dr, 99% ee). Of particular note, this approach accomplishes unattainable photochemical asymmetric transformations of aldehydes with disparate carbonyl partners without reliance on any external photosensitizer, thereby further emphasizing its versatility and cost-efficiency.

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