Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.846
Filtrar
1.
Oncol Lett ; 27(6): 242, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38618644

RESUMO

Chemoradiotherapy (CRT) followed by consolidation of immune checkpoint inhibitors (ICIs), such as durvalumab or pembrolizumab, for patients with unresectable, locally advanced non-small cell lung cancer (NSCLC) with tumor PD-L1 expression <1% remains a topic of controversy. Previous studies from PubMed, Cochrane Library and Embase databases were searched for a meta-analysis. A total of 16 studies were included in part one of the meta-analysis and it was observed that consolidation of ICIs after CRT improved overall survival (OS) [hazard ratio (HR) 1.46; P=0.005] and progression-free survival (PFS) (HR 1.26; P=0.023) for the patients with PD-L1 expression ≥1% compared with those with PD-L1 expression <1%. Then, 15 studies were included in part two of the meta-analysis and the results indicated that the pooled 1, 2 and 3-year OS were 77% vs. 83% (P=0.07), 55% vs. 59% (P=0.327) and 38% vs. 51% (P=0.006) for CRT alone compared with CRT followed by consolidation of ICIs, respectively. The pooled 1, 2 and 3-year PFS were 51% vs. 53% (P=0.632), 29% vs. 40% (P=0.015) and 20% vs. 28% (P=0.153) for CRT alone compared with CRT followed by consolidation of ICIs, respectively. The findings of the present study highlighted that the benefits of CRT followed by consolidation of ICIs were higher compared with CRT alone in patients with unresectable, locally advanced NSCLC and PD-L1 expression <1%. Consolidation of ICIs after CRT would provide greater benefits for locally advanced NSCLC patients with PD-L1 expression ≥1% compared with those with PD-L1 expression <1%.

2.
J Med Virol ; 96(4): e29607, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38628076

RESUMO

Hepatitis B e antigen (HBeAg) seropositivity during the natural history of chronic hepatitis B (CHB) is known to coincide with significant increases in serum and intrahepatic HBV DNA levels. However, the precise underlying mechanism remains unclear. In this study, we found that PreC (HBeAg precursor) genetic ablation leads to reduced viral replication both in vitro and in vivo. Furthermore, PreC impedes the proteasomal degradation of HBV polymerase, promoting viral replication. We discovered that PreC interacts with SUV39H1, a histone methyltransferase, resulting in a reduction in the expression of Cdt2, an adaptor protein of CRL4 E3 ligase targeting HBV polymerase. SUV39H1 induces H3K9 trimethylation of the Cdt2 promoter in a PreC-induced manner. CRISPR-mediated knockout of endogenous SUV39H1 or pharmaceutical inhibition of SUV39H1 decreases HBV loads in the mouse liver. Additionally, genetic depletion of Cdt2 in the mouse liver abrogates PreC-related HBV replication. Interestingly, a negative correlation of intrahepatic Cdt2 with serum HBeAg and HBV DNA load was observed in CHB patient samples. Our study thus sheds light on the mechanistic role of PreC in inducing HBV replication and identifies potential therapeutic targets for HBV treatment.


Assuntos
Vírus da Hepatite B , Hepatite B Crônica , Animais , Camundongos , Humanos , Vírus da Hepatite B/genética , Antígenos E da Hepatite B , DNA Viral , Replicação Viral , Metiltransferases , Proteínas Repressoras/genética
3.
RSC Adv ; 14(17): 11885-11890, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38628479

RESUMO

We report the synthesis of xNi-yFe/γ-Al2O3 catalysts which were applied to the reductive amination of polypropylene glycol (PPG) for the preparation of polyether amine (PEA). The catalysts were characterized by N2-sorption, X-ray diffraction, H2-temperature programmed reduction, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy to reveal the synergistic effect of the bimetallic Ni-Fe-loaded catalysts. It was found that in the reductive amination of PPG to PEA, the conversion and product selectivity of the reaction were closely related to the types of active centers of the catalyst. In particular, the surface Ni0 content increased by adding Fe as a promoter, with a maximum Ni0 content on the 15Ni-7.5Fe/Al2O3 catalyst, which also led to the highest conversion rate (>99%). In addition, no deactivation was observed after three cycles of reaction carried out by the catalyst.

4.
Food Chem ; 450: 139297, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38631199

RESUMO

This study aimed to investigate the antioxidative and cytoprotective activity of antioxidant peptides from fermented broad bean paste (FBBP) and explore their potential molecular mechanisms using a combined in silico and in vitro approach. Seven novel antioxidant peptides (VSRRFIYYL, SPAIPLP, PVPPPGG, KKDGYWWAKFK, LAWY, LGFMQF, and LPGCP) identified by integrated approaches of peptidomics and in silico bioinformatic analysis were synthesized, exhibiting strong antioxidant potential against in vitro radicals. Molecular docking results suggested that these peptides could form stable hydrogen bonds and solvent-accessible surface with key amino acid residues of Keap1, thus potentially regulating the Keap1-Nrf2 pathway by occupying the Nrf2-binding site on Keap1. Additionally, they exhibited strong cellular antioxidant activity and could protect HepG2 cells from AAPH-induced oxidative injury by reducing reactive oxygen species and MDA accumulation. This study firstly unraveled the molecular mechanisms of antioxidant peptides from FBBP, and provided a new theoretical basis for the high-value utilization of FBBP.

5.
Sci Total Environ ; 927: 172191, 2024 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-38588738

RESUMO

Although the formation, turnover, and accumulation of soil organic carbon (SOC) are driven by different fertilizer inputs and their subsequent microbial-mediated transformation, the relationship between changes in plant-derived and microbial-derived components and soil microbial life history strategies under different fertilization regimes has not been well explored. In this study, the changes in microbial necromass carbon (MNC), lignin phenols, and glomalin-related soil protein (GRSP), as well as soil microbial life history strategy were determined in a 16-year field experiment in response to different fertilization regimes, including a no-fertilizer control (C), conventional chemical NPK fertilization (NPK), and partial substitutions of the NPK in chemical fertilizers with a low (30 %) or high (60 %) level of straw (0.3S and 0.6S) or cattle manure (0.3M and 0.6M). The results showed that total lignin phenol content and its contribution to SOC were significantly increased by 88.7 % and 74.2 %, respectively, in high-level straw substitution treatment as compared to chemical fertilization. Both high-level straw and cattle manure substitution increased MNC and total GRSP contents, but did not alter their contributions to SOC compared to chemical fertilization. In fertilized treatments, the high-level cattle manure substitution had the lowest and highest bacterial and fungal K/r ratio, respectively. Bacterial K/r ratio was an important factor in predicting bacterial necromass carbon content and there was a significant negative correlation between them. The ratio of ectomycorrhizal to saprotrophic fungi and fungal diversity were important factors for predicting lignin phenol and GRSP contents, respectively. In addition, the SEMs modeling indicated that straw substitution directly affected lignin phenol and MNC accumulation, whereas cattle manure substitution indirectly affected MNC accumulation by affecting microbial life history strategies. In conclusions, agricultural residues inputs support the formation of a multiple carbon pool of SOC compared to chemical fertilization; and microbial life history strategy is an important driver of SOC formation and affects SOC accumulation and stability in agroecosystems.

6.
J Colloid Interface Sci ; 666: 594-602, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38613981

RESUMO

Tailoring the omnidirectional conductivity networks in nickel oxide-based electrodes is important for ensuring their long lifespan, stability, high capacity, and high-rate capability. In this study, nickel metal nanoparticles and a three-dimensional nitrogen-doped carbon matrix were used to embellish the nickel oxide composite NiO-Ni/N-C via simplified hard templating. When a porous nitrogen-doped carbon matrix is present, a rapid pathway would be established for charging and discharging the electrons and lithium ions in a lithium-ion battery, thereby alleviating the volumetric expansion of the NiO nanoparticles during the operation of the battery. Moreover, the Ni0 ions added to serve as active sites to improve the capacity of the NiO-based electrodes and strengthen their conductivities. The multielement-effects of the optimal NiO-Ni/N-C electrode leads it to exhibit a capacity of 1310.8 mAh g-1 at 0.1 A g-1 for 120 loops and a rate capability of 441.5 mAh g-1 at 20.0 A g-1. Kinetic analysis of the prepared electrodes proved their ultrafast ionic and electronic conductivities. This strategy of hard templating reduces the number of routes required for preparing different types of electrodes, including NiO-based electrodes, and improves their electrochemical performance to enable their use in energy storage applications.

7.
Eur J Oncol Nurs ; 70: 102565, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38615513

RESUMO

PURPOSE: To evaluate the clinical effects of a couple-focused dyadic coping intervention in colorectal cancer (CRC) couples. METHODS: The study was a single-blinded randomized controlled study which 226 CRC couples were recruited and randomized to either the intervention (N = 113) or the control (N = 113) group. All couples received usual care while the six-week dyadic coping intervention was provided to the intervened couples in psycho-education and skill training methods through face-to-face combined with telephone formats. Measurement data, including dyadic coping, marital satisfaction, quality of life and psychological well-being were collected at pre- and post-intervention periods. And multilevel model (MLM) was applied to analyze the effects of the intervention and the role tendency. RESULTS: A total of 173 couples completed the program and post-intervention evaluation. The retention rate was 76.5%. Results from MLM showed that the dyadic coping intervention is effective in promoting levels of dyadic coping (P < 0.001), marital satisfaction (P = 0.042), mental health (P = 0.006), and positive psychological well-being (P < 0.001), and alleviating depression (P = 0.015) in CRC couples. For role tendency, the intervention found to be more effective in CRC spousal caregivers' positive psychological well-being compared to the patients (P = 0.037). CONCLUSION: The couple-based dyadic coping intervention is effective in promoting dyadic coping and improving psychological adjustment in CRC couples. More studies were needed to further evaluate the program and its long-term efficacy in the future. In addition, given the positive effects of the intervention, clinical nursing stuffs may consider implementing such intervention in their routine work while caring for CRC couples.

8.
Wei Sheng Yan Jiu ; 53(2): 294-299, 2024 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-38604967

RESUMO

OBJECTIVE: To establish an analytical method for determining the migration of 24 elements in Yixing clay pottery in 4% acetic acid simulated solution by inductively coupled plasma mass spectrometry. METHODS: Four types of Yixing clay pottery, including Yixing clay teapot, Yixing clay kettle, Yixing clay pot, and Yixing clay electric stew pot, were immersed in 4% acetic acid as a food simulant for testing. The migration amount of 24 elements in the migration solution was determined using inductively coupled plasma mass spectrometry. RESULTS: Lithium, magnesium, aluminum, iron, and barium elements with a mass concentration of 1000 µg/L; Lead, cadmium, total arsenic, chromium, nickel, copper, vanadium, manganese, antimony, tin, zinc, cobalt, molybdenum, silver, beryllium, thallium, titanium, and strontium elements within 100 µg/L there was a linear relationship within, the r value was between 0.998 739 and 0.999 989. Total mercury at 5.0 µg/L, there was a linear relationship within, the r value of 0.995 056. The detection limit of the elements measured by this method was between 0.5 and 45.0 µg/L, the recovery rate was 80.6%-108.9%, and the relative standard deviation was 1.0%-4.8%(n=6). A total of 32 samples of four types of Yixing clay pottery sold on the market, including teapots, boiling kettles, casseroles, and electric stewing pots, were tested. It was found that the migration of 16 elements, including beryllium, titanium, chromium, nickel, cobalt, zinc, silver, cadmium, antimony, total mercury, thallium, tin, copper, total arsenic, molybdenum, and lead, were lower than the quantitative limit. The element with the highest migration volume teapot was aluminum, magnesium, and barium; The kettle was aluminum and magnesium; Casserole was aluminum, magnesium, and lithium; The electric stew pot was aluminum. CONCLUSION: This method is easy to operate and has high accuracy, providing an effective and feasible detection method for the determination and evaluation of element migration in Yixing clay pottery.


Assuntos
Arsênio , Mercúrio , Oligoelementos , Cobre , Molibdênio/análise , Níquel , Argila , Magnésio , Alumínio/análise , Cádmio/análise , Bário/análise , Titânio/análise , Prata/análise , Berílio/análise , Estanho/análise , Arsênio/análise , Lítio/análise , Antimônio/análise , Tálio/análise , Zinco , Cromo , Cobalto/análise , Mercúrio/análise , Espectrometria de Massas , Acetatos , Oligoelementos/análise
9.
10.
J Agric Food Chem ; 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38557018

RESUMO

In this study, in silico analysis and peptidomics were performed to examine the generation mechanism of the umami taste of fermented broad bean paste (FBBP). Based on the information from peptidomics, a total of 470 free peptides were identified from FBBP, most of which were increased after fermentation. Additionally, the increase of the content of umami peptides, organic acids, and amino acids during fermentation contributed to the perception of umami taste in FBBP. Molecule docking results inferred that these umami molecules were easy to connect with Ser, Glu, His, and Gln in the T1R3 subunit through hydrogen bonds and electrostatic interaction force. The binding sites His145, Gln389, and Glu301 particularly contributed to the formation of the ligand-receptor complexes. The aromatic interaction, hydrogen bond, hydrophilicity, and solvent-accessible surface (SAS) played key roles in the receptor-peptide interaction. Sensory evaluation and electronic tongue results showed that EDEDE, DLSESV, SNGDDE, DETL, CDLSD, and TDEE screened from FBBP had umami characteristics and umami-enhancing effects (umami threshold values ranging from 0.131 to 0.394 mmol/L). This work provides new insight into the rapid and efficient screening of novel umami peptides and a deeper understanding of the taste mechanisms of umami molecules from FBBP.

11.
Opt Express ; 32(7): 12982-12991, 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38571104

RESUMO

Quantum dense metrology (QDM) performs high-precision measurements by a two-mode entangled state created by an optical parametric amplifier (PA), where one mode is a meter beam and the other is a reference beam. In practical applications, the photon losses of meter beam are unavoidable, resulting in a degradation of the sensitivity. Here, we employ coherent feedback that feeds the reference beam back into the PA by a beam splitter to enhance the sensitivity in a lossy environment. The results show that the sensitivity is enhanced significantly by adjusting the splitting ratio of the beam splitter. This method may find its potential applications in QDM. Furthermore, such a strategy that two non-commuting observables are simultaneous measurements could provide a new way to individually control the noise-induced random drift in phase or amplitude of the light field, which would be significant for stabilizing the system and long-term precision measurement.

12.
Chempluschem ; : e202400161, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38593244

RESUMO

Hierarchical self-assembly has been recently employed in the construction of anion-coordination-driven gel materials. However, the post-assembly modification strategy, which may be a highly efficient strategy to realize the functionalization of discrete 'aniono' supramolecular architectures, has not been employed yet. Herein we report the first example of anion-coordination-driven gel material cross-linked by well-defined 'aniono' triple helicate through post-assembly polymerization. The obtained gel shows self-healing property and excellent compatibility with various surfaces, including glass, rubber, leaf, PP, and metal. The viscoelastic gel constructed through the post-assembly modification strategy enriches the method to construct the anion-coordination-driven smart materials.

13.
Chemosphere ; 356: 141906, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38583534

RESUMO

Atrazine (ATR) is one of the most commonly used herbicides worldwide. As an endocrine disruptor, it causes ovarian dysfunction, but the mechanism is unclear. We hypothesized that ATR could affect ovarian steroidogenesis, oxidative stress, inflammation, and apoptosis. In the current study, rats aged 28 days were treated with PMSG and HCG to obtain amounts of corpora lutea. Then, rats were injected with ATR (50 mg/kg/day) or saline (0.9%) for 7 days. Sera were collected to detect biochemical indices and progesterone (P4) level, ovaries were collected for antioxidant status, HE, qPCR, and WB analysis. Results showed that ATR exposure affected growth performance as well as serum TP, GLB, and ALB levels, increased serum P4 level and ovarian mRNA and protein levels of StAR, CYP11A1, and HSD3B. ATR treatment increased ovarian mRNA and protein levels of CREB but not PKA expression. ATR treatment increased ovarian mRNA abundances of Nrf-2 and Nqo1, MDA level, and decreased SOD, GST, and T-AOC levels. ATR exposure increased the mRNA abundances of pro-inflammatory cytokines including Tnf-α, Il-1ß, Il-6, Il-18, and Inos. ATR exposure increased the mRNA and protein level of Caspase 3 and the ratio of BAX/BCL-2. In conclusion, NRF-2/NQO1 signaling pathway and CREB might be involved in the regulation of ATR in luteal steroidogenesis, oxidative stress, inflammation, and apoptosis in rat ovary.

14.
BMC Cancer ; 24(1): 438, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38594670

RESUMO

PURPOSE: Based on the quantitative and qualitative features of CT imaging, a model for predicting the invasiveness of ground-glass nodules (GGNs) was constructed, which could provide a reference value for preoperative planning of GGN patients. MATERIALS AND METHODS: Altogether, 702 patients with GGNs (including 748 GGNs) were included in this study. The GGNs operated between September 2020 and July 2022 were classified into the training group (n = 555), and those operated between August 2022 and November 2022 were classified into the validation group (n = 193). Clinical data and the quantitative and qualitative features of CT imaging were harvested from these patients. In the training group, the quantitative and qualitative characteristics in CT imaging of GGNs were analyzed by using performing univariate and multivariate logistic regression analyses, followed by constructing a nomogram prediction model. The differentiation, calibration, and clinical practicability in both the training and validation groups were assessed by the nomogram models. RESULTS: In the training group, multivariate logistic regression analysis disclosed that the maximum diameter (OR = 4.707, 95%CI: 2.06-10.758), consolidation/tumor ratio (CTR) (OR = 1.027, 95%CI: 1.011-1.043), maximum CT value (OR = 1.025, 95%CI: 1.004-1.047), mean CT value (OR = 1.035, 95%CI: 1.008-1.063; P = 0.012), spiculation sign (OR = 2.055, 95%CI: 1.148-3.679), and vascular convergence sign (OR = 2.508, 95%CI: 1.345-4.676) were independent risk parameters for invasive adenocarcinoma. Based on these findings, we established a nomogram model for predicting the invasiveness of GGN, and the AUC was 0.910 (95%CI: 0.885-0.934) and 0.902 (95%CI: 0.859-0.944) in the training group and the validation group, respectively. The internal validation of the Bootstrap method showed an AUC value of 0.905, indicating a good differentiation of the model. Hosmer-Lemeshow goodness of fit test for the training and validation groups indicated that the model had a good fitting effect (P > 0.05). Furthermore, the calibration curve and decision analysis curve of the training and validation groups reflected that the model had a good calibration degree and clinical practicability. CONCLUSION: Combined with the quantitative and qualitative features of CT imaging, a nomogram prediction model can be created to forecast the invasiveness of GGNs. This model has good prediction efficacy for the invasiveness of GGNs and can provide help for the clinical management and decision-making of GGNs.


Assuntos
Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/cirurgia , Neoplasias Pulmonares/patologia , Nomogramas , Tomografia Computadorizada por Raios X/métodos , Invasividade Neoplásica/patologia , Adenocarcinoma de Pulmão/diagnóstico por imagem , Adenocarcinoma de Pulmão/cirurgia , Adenocarcinoma de Pulmão/patologia , Estudos Retrospectivos
15.
Aging (Albany NY) ; 16(7): 6384-6416, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38575325

RESUMO

BACKGROUND: COVID-19 pandemic poses a heavy burden on public health and accounts for substantial mortality and morbidity. Proteins are building blocks of life, but specific proteins causally related to COVID-19, healthspan and lifespan have not been systematically examined. METHODS: We conducted a Mendelian randomization study to assess the effects of 1,361 plasma proteins on COVID-19, healthspan and lifespan, using large GWAS of severe COVID-19 (up to 13,769 cases and 1,072,442 controls), COVID-19 hospitalization (32,519 cases and 2,062,805 controls) and SARS-COV2 infection (122,616 cases and 2,475,240 controls), healthspan (n = 300,477) and parental lifespan (~0.8 million of European ancestry). RESULTS: We identified 35, 43, and 63 proteins for severe COVID, COVID-19 hospitalization, and SARS-COV2 infection, and 4, 32, and 19 proteins for healthspan, father's attained age, and mother's attained age. In addition to some proteins reported previously, such as SFTPD related to severe COVID-19, we identified novel proteins involved in inflammation and immunity (such as ICAM-2 and ICAM-5 which affect COVID-19 risk, CXCL9, HLA-DRA and LILRB4 for healthspan and lifespan), apoptosis (such as FGFR2 and ERBB4 which affect COVID-19 risk and FOXO3 which affect lifespan) and metabolism (such as PCSK9 which lowers lifespan). We found 2, 2 and 3 proteins shared between COVID-19 and healthspan/lifespan, such as CXADR and LEFTY2, shared between severe COVID-19 and healthspan/lifespan. Three proteins affecting COVID-19 and seven proteins affecting healthspan/lifespan are targeted by existing drugs. CONCLUSIONS: Our study provided novel insights into protein targets affecting COVID-19, healthspan and lifespan, with implications for developing new treatment and drug repurposing.

16.
Eur J Med Chem ; 271: 116401, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38640870

RESUMO

Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) cause more than 100,000 deaths each year, which need efficient and non-resistant antibacterial agents. SAR analysis of 162 flavonoids from the plant in this paper suggested that lipophilic group at C-3 was crucial, and then 63 novel flavonoid derivatives were designed and total synthesized. Among them, the most promising K15 displayed potent bactericidal activity against clinically isolated MRSA and VRE (MICs = 0.25-1.00 µg/mL) with low toxicity and high membrane selectivity. Moreover, mechanism insights revealed that K15 avoided resistance by disrupting biofilm and targeting the membrane, while vancomycin caused 256 times resistance against MRSA, and ampicillin caused 16 times resistance against VRE by the same 20 generations inducing. K15 eliminated residual bacteria in mice skin MRSA-infected model (>99 %) and abdominal VRE-infected model (>92 %), which was superior to vancomycin and ampicillin.

17.
Adv Mater ; : e2312887, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38606800

RESUMO

Low-barrier and high-injection electrodes are crucial for high-performance (HP) 2D semiconductor devices. Conventional trial-and-error methodologies for electrode material screening are impractical because of their low efficiency and arbitrary specificity. Although machine learning has emerged as a promising alternative to tackle this problem, its practical application in semiconductor devices is hindered by its substantial data requirements. In this paper, a comprehensive scheme combining an autoencoding regularized adversarial neural network and a feature-adaptive variational active learning algorithm for screening low-contact electrode materials for 2D semiconductor transistors with limited data is proposed. The proposed scheme exhibits exceptional performance by training with only 15% of the total data points, where the mean square errors are 0.17 and 0.27 eV for the vertical and lateral Schottky barrier, respectively, and 2.88% for tunneling probability. Further, it exhibits an optimal predictive performance for 100 randomly sampled training datasets, reveals the underlying physical insight based on the identified features, and realizes continual improvement by employing detailed density-of-states descriptors. Finally, the empirical evaluations of the transport characteristics are conducted and verified by constructing MOSFET devices. These findings demonstrate the considerable potential of machine-learning techniques for screening high-efficiency electrode materials and constructing HP 2D semiconductor devices.

18.
J Am Chem Soc ; 146(15): 10847-10856, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38583085

RESUMO

Transition-metal-catalyzed carbene insertion reactions of a nitrogen-hydrogen bond have emerged as robust and versatile methods for the construction of C-N bonds. While significant progress of homogeneous catalytic metal carbene N-H insertions has been achieved, the control of chemoselectivity in the field remains challenging due to the high electrophilicity of the metal carbene intermediates. Herein, we present an efficient strategy for the synthesis of a rhodium single-atom-site catalyst (Rh-SA) that incorporates a Rh atom surrounded by three nitrogen atoms and one phosphorus atom doped in a carbon support. This Rh-SA catalyst, with a catalyst loading of only 0.15 mol %, exhibited exceptional catalytic performance for heterogeneous carbene insertion with various anilines and heteroaryl amines in combination with diazo esters. Importantly, the heterogeneous catalyst selectively transformed aniline derivatives bearing multiple nucleophilic moieties into single N-H insertion isomers, while the popular homogeneous Rh2(OAc)4 catalyst produced a mixture of overfunctionalized side products. Additionally, similar selectivities for N-H bond insertion with a set of stereoelectronically diverse diazo esters were obtained, highlighting the general applicability of this heterogeneous catalysis approach. On the basis of density functional theory calculations, the observed selectivity of the Rh-SA catalyst was attributed to the insertion barriers and the accelerated proton transfer assisted by the phosphorus atom in the support. Overall, this investigation of heterogeneous metal-catalyzed carbene insertion underscores the potential of single-atom-site catalysis as a powerful and complementary tool in organic synthesis.

19.
Food Chem ; 449: 139203, 2024 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-38599105

RESUMO

This study examined the interaction between myofibrillar proteins (MPs) and the numbing substance hydroxy-α-sanshool (α-SOH) in a thermal environment, and provided an explanation of the numbness perception mechanism through muti-spectroscopic and molecular dynamics simulation methodology. Results showed that addition of α-SOH could reduce the particle size and molecular weight of MPs, accompanied by changes in the tertiary and secondary structure, causing the α-helix of MPs transitioned to ß-sheet and ß-turn due to the reorganization of hydrogen bonds. After a moderate heating (60 or 70 °C), MPs could form the stable complexes with α-SOH that were associated with attachment sites and protein wrapping. The thermal process might convert a portion of α-SOH' into hydroxy-ß-sanshool' (ß-SOH'). When docking with the sensory receptor TRPV1, the RMSD, RMSF and binding free energy all showed that ß-SOH' demonstrated a low affinity, thereby reducing the numbing perception. These findings can provide a theoretical foundation for the advanced processing of numbing meat products.

20.
Artigo em Inglês | MEDLINE | ID: mdl-38581328

RESUMO

Objective: The measurement of the right and left axillary arteries and aortic arch and their vessels by multi-row spiral CT angiography provides the basis for clinical catheter selection and depth for axillary artery placement. This study reported the clinical experience of 7 patients who successfully underwent ultrasound-guided percutaneous axillary artery cannulation for veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Methods: Patients who had CT angiography of the thoracic aorta at our institution between January 2020 and March 2022 were assessed for eligibility and included. The diameters of the cephalic trunk (D1), right common carotid artery (D2), right axillary artery (D3), left common carotid artery (D4), left axillary artery opening (D5), right axillary artery cannulation length (L1), and left axillary artery cannulation length (L2) were measured. The tangential angles α, ß, and γ of the cephalic trunk, left common carotid artery and left subclavian and aorta was measured using an automatic angle-forming tool. The decision to use a 15F cannula for ultrasound-guided percutaneous axillary artery cannulation in veno-arterial extracorporeal membrane oxygenation (VA-ECMO) aims to achieve optimal vascular access. This cannula size strikes a balance, providing sufficient blood flow rates for ECMO support while minimizing the risk of complications associated with larger cannulas. Precise measurements of arterial dimensions, including the cephalic trunk, common carotid arteries, and axillary arteries, play a crucial role in guiding catheter selection and determining the depth of axillary artery placement. These measurements allow for tailored approaches based on individual patient characteristics, enhancing the safety and efficacy of the intervention. Additionally, measuring tangential angles (α, ß, and γ) provides insights into arterial alignment, optimizing the cannula trajectory for efficient blood flow. The use of an automatic angle-forming tool enhances measurement precision, contributing to procedural accuracy, minimizing complications, and ensuring the success of ultrasound-guided percutaneous axillary artery cannulation. In summary, the choice of a 15F cannula and precise measurements are essential components of the methodology, emphasizing safety, efficacy, and personalized approaches in VA-ECMO. From March to June 2022, 7 patients (6 males and 1 female) in our intensive care medicine department underwent successful ultrasound-guided percutaneous axillary artery cannulation for VA-ECMO with 15F cannula, including 3 cases with extracorporeal cardiopulmonary resuscitation (ECPR) and 4 cases with circulatory collapse. Results: 292 patients met the study criteria, 215 males and 77 females, with a mean age of 67.2±14.2 years. The measurements showed that D1 was (13.1±2.0) mm, D2 was (8.8±2.5) mm, D3 was (6.1±1.2) mm, D4 was (8.3±3.5) mm, D5 was (6.1±1.1) mm, L1 was (114.1±17.8) mm, and L2 was (128.4±20.2) mm. The tangential angles α of the cephalic trunk left common carotid artery and left subclavian artery to the aorta were (43.8°±17.1°), ß was (50.7°±14.8°), and γ was (62.4°±19.1°). Males had significantly wider D3 and D5, longer L1 and L2, and smaller gamma angles than females (P < .05). Three ECPR cases showed no recovery of the spontaneous heartbeat with femoral artery cannulation for VA-ECMO but recovered spontaneous heartbeat after axillary artery cannulation for VA-ECMO was adopted. The measurements in this study have important implications for veno-arterial extracorporeal membrane oxygenation (VA-ECMO) procedures. They provide crucial information about arterial dimensions, including the cephalic trunk, common carotid arteries, and axillary arteries. This information guides clinicians in selecting catheters and determining the ideal depth for percutaneous axillary artery cannulation during ECMO interventions. Notable gender differences in arterial dimensions highlight the need for personalized approaches in ECMO procedures. Customizing catheter choices and cannulation depth based on individual patient characteristics, informed by these measurements, improves the safety and effectiveness of the intervention. The measured tangential angles (α, ß, and γ) offer insights into arterial alignment, crucial for optimizing cannula trajectory and ensuring proper alignment for efficient blood flow. The use of an automatic angle-forming tool enhances measurement precision, contributing to procedural accuracy and minimizing the risk of complications during ECMO procedures. In summary, these measurements directly enhance the precision and safety of VA-ECMO procedures, underscoring the importance of personalized approaches based on individual anatomical variations and improving overall intervention success and outcomes. Conclusion: Ultrasound-guided percutaneous axillary artery cannulation for VA-ECMO with a 15F cannula is clinically feasible. Axillary artery cannulation for VA-ECMO contributes to the restoration of spontaneous heartbeat in ECPR patients more than femoral artery cannulation, and the possible mechanism is a better improvement of coronary blood flow. However, the study has limitations, including a modest sample size and a single-center, retrospective design, impacting its generalizability. To validate and extend these findings, further research with larger and diverse cohorts, including prospective investigations, is necessary to ensure their applicability across various clinical settings and patient demographics in VA-ECMO.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...