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1.
Emerg Microbes Infect ; : 2382236, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39017656

RESUMO

The incompletely eliminated Treponema pallidum (T. pallidum) during primary syphilis chancre infection can result in the progression of secondary, tertiary, or latent syphilis in individuals, suggesting that T. pallidum has successfully evaded the immune response and spread to distant sites. The mechanism underlying the dissemination of T. pallidum is unclear. Here, a syphilitic rabbit model dorsal-injected with recombinant Tp0136 protein or Tp0136 antibody subcutaneously was used to demonstrate the role of Tp0136 protein in promoting the dissemination of T. pallidum to the testis and angiogenesis in vivo; vascular endothelial cell line HMEC-1 was employed to display that Tp0136 protein enhances the angiogenesis. Furthermore, the three-dimensional microfluidic angiogenesis system showed that the angiogenesis would heighten vascular permeability. Then transcriptome sequencing analysis, in conjunction with cell-level validation, elucidated the critical role of the PI3K-AKT signaling pathway in the promotion of angiogenesis by Tp0136 protein, resulting in heightened permeability. These findings elucidate the strategy employed by T. pallidum in evading immune clearance.

2.
ACS Appl Mater Interfaces ; 16(28): 36047-36062, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-38978477

RESUMO

Sepsis, a life-threatening condition caused by a dysregulated immune response to infection, leads to systemic inflammation, immune dysfunction, and multiorgan damage. Various oxidoreductases play a very important role in balancing oxidative stress and modulating the immune response, but they are stored inconveniently, environmentally unstable, and expensive. Herein, we develop multifunctional artificial enzymes, CeO2 and Au/CeO2 nanozymes, exhibiting five distinct enzyme-like activities, namely, superoxide dismutase, catalase, glutathione peroxidase, peroxidase, and oxidase. These artificial enzymes have been used for the biocatalytic treatment of sepsis via inhibiting inflammation and modulating immune responses. These nanozymes significantly reduce reactive oxygen species and proinflammatory cytokines, achieving multiorgan protection. Notably, CeO2 and Au/CeO2 nanozymes with enzyme-mimicking activities can be particularly effective in restoring immunosuppression and maintaining homeostasis. The redox nanozyme offers a promising dual-protective strategy against sepsis-induced inflammation and organ dysfunction, paving the way for biocatalytic-based immunotherapies for sepsis and related inflammatory diseases.


Assuntos
Cério , Ouro , Inflamação , Sepse , Sepse/tratamento farmacológico , Sepse/imunologia , Animais , Inflamação/tratamento farmacológico , Inflamação/imunologia , Ouro/química , Cério/química , Cério/uso terapêutico , Camundongos , Humanos , Espécies Reativas de Oxigênio/metabolismo , Catalase/metabolismo , Catalase/química , Citocinas/metabolismo
3.
Chin J Integr Med ; 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38958884

RESUMO

Hypertensive renal damage (HRD) is a major cause of end-stage renal disease. Among the causes of end-stage renal disease, HRD accounts for nearly 34% of the total number of cases. Antihypertensive treatment is primarily drug-based, but therapeutic efficacy is less effective and can have serious side effects. Chinese medicine (CM) has significant advantages in the treatment of HRD. CM is rich in various active ingredients and has the property of targeting multiple targets and channels. Therefore, the regulatory network of CM on disease is complex. A large number of CM have been employed to treat HRD, either as single applications or as part of compound formulations. The key possible mechanisms of CM for HRD include regulation of the renin-angiotensin-aldosterone system, antioxidation, anti-inflammation, rescue of endothelial function, regulation of vasoactive substance secretion and obesity-related factors, etc. This review summarized and discussed the recent advance in the basic research mechanisms of CM interventions for HRD and pointed out the challenges and future prospects.

4.
Sci Total Environ ; 946: 174057, 2024 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-38914340

RESUMO

Root-associated microbiota provide great fitness to hosts under environmental stress. However, the underlying microecological mechanisms controlling the interaction between heavy metal-stressed plants and the microbiota are poorly understood. In this study, we screened and isolated representative amplicon sequence variants (strain M4) from rhizosphere soil samples of Trifolium repens L. growing in areas with high concentrations of heavy metals. To investigate the microecological mechanisms by which T. repens adapts to heavy metal stress in abandoned mining areas, we conducted potting experiments, bacterial growth promotion experiments, biofilm formation experiments, and chemotaxis experiments. The results showed that high concentrations of heavy metals significantly altered the rhizosphere bacterial community structure of T. repens and significantly enriched Microbacterium sp. Strain M4 was demonstrated to significantly increased the biomass and root length of T. repens under heavy metal stress. Additionally, L-proline and stigmasterol could promote bacterial growth and biofilm formation and induce chemotaxis for strain M4, suggesting that they are key rhizosphere secretions of T. repens for Microbacterium sp. recruitment. Our results suggested that T. repens adapted the heavy metal stress by reshaping rhizosphere secretions to modify the rhizosphere microbiota.

5.
J Agric Food Chem ; 72(27): 15293-15300, 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38940657

RESUMO

Hydroxytyrosol, a naturally occurring compound with antioxidant and antiviral activity, is widely applied in the cosmetic, food, and nutraceutical industries. The development of a biocatalytic approach for producing hydroxytyrosol from simple and readily accessible substrates remains a challenge. Here, we designed and implemented an effective biocatalytic cascade to obtain hydroxytyrosol from 3,4-dihydroxybenzaldehyde and l-threonine via a four-step enzymatic cascade composed of seven enzymes. To prevent cross-reactions and protein expression burden caused by multiple enzymes expressed in a single cell, the designed enzymatic cascade was divided into two modules and catalyzed in a stepwise manner. The first module (FM) assisted the assembly of 3,4-dihydroxybenzaldehyde and l-threonine into (2S,3R)-2-amino-3-(3,4-dihydroxyphenyl)-3-hydroxypropanoic acid, and the second module (SM) entailed converting (2S,3R)-2-amino-3-(3,4-dihydroxyphenyl)-3-hydroxypropanoic acid into hydroxytyrosol. Each module was cloned into Escherichia coli BL21 (DE3) and engineered in parallel by fine-tuning enzyme expression, resulting in two engineered whole-cell catalyst modules, BL21(FM01) and BL21(SM13), capable of converting 30 mM 3,4-dihydroxybenzaldehyde to 28.7 mM hydroxytyrosol with a high space-time yield (0.88 g/L/h). To summarize, the current study proposes a simple and effective approach for biosynthesizing hydroxytyrosol from low-cost substrates and thus has great potential for industrial applications.


Assuntos
Biocatálise , Escherichia coli , Álcool Feniletílico , Álcool Feniletílico/análogos & derivados , Álcool Feniletílico/química , Álcool Feniletílico/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Benzaldeídos/química , Benzaldeídos/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química
6.
Artigo em Inglês | MEDLINE | ID: mdl-38863365

RESUMO

OBJECTIVES: Pseudomonas aeruginosa and Acinetobacter baumannii are ranked as top-priority organisms by WHO. Antimicrobial peptides (AMPs) are promising antimicrobial agents that are highly effective against serious bacterial infections. METHODS: In our previous study, a series of α-helical AMPs were screened using a novel multiple-descriptor strategy. The current research suggested that S24 exhibited strong antimicrobial activity against major pathogenic bacteria, and displayed minimal haemolysis, good serum stability and maintained salt resistance. RESULTS: We found that S24 exerted an antimicrobial effect by destroying outer membrane permeability and producing a strong binding effect on bacterial genomic DNA that inhibits genomic DNA migration. Furthermore, S24 exerted a strong ability to promote healing in wound infected by P. aeruginosa, A. baumannii and mixed strains in a mouse model. CONCLUSIONS: Overall, S24 showed good stability under physiological conditions and excellent antimicrobial activity, suggesting it may be a potential candidate for the development of serious bacterial infection treatment.

7.
Chemistry ; : e202402247, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38923595

RESUMO

Vinylidene ortho-quinone methides (VQMs) have been proven to be versatile and crucial intermediates in the catalytic asymmetric reaction in last decade, and thus have drawn considerable concentrations on account of the practical application in the construction of enantiomerically pure functional organic molecules. However, in comparison to the well established chiral Brønsted base-catalyzed asymmetric reaction via VQMs, chiral Brønsted acid-catalyzed reaction is rarely studied and there is no systematic summary to date. In this review, we summarize the recent advances in the chiral Brønsted acid-catalyzed asymmetric reaction via VQMs according to three types of reactions: a) intermolecular asymmetric nucleophilic addition to VQMs; b) intermolecular asymmetric cycloaddition of VQMs; c) intramolecular asymmetric cyclization of VQMs. Finally, we put forward the remained challenges and opportunities for potential breakthroughs in this area.

8.
Zhongguo Dang Dai Er Ke Za Zhi ; 26(6): 611-618, 2024 Jun 15.
Artigo em Chinês | MEDLINE | ID: mdl-38926378

RESUMO

OBJECTIVES: To investigate the risk factors for bronchopulmonary dysplasia (BPD) in twin preterm infants with a gestational age of <34 weeks, and to provide a basis for early identification of BPD in twin preterm infants in clinical practice. METHODS: A retrospective analysis was performed for the twin preterm infants with a gestational age of <34 weeks who were admitted to 22 hospitals nationwide from January 2018 to December 2020. According to their conditions, they were divided into group A (both twins had BPD), group B (only one twin had BPD), and group C (neither twin had BPD). The risk factors for BPD in twin preterm infants were analyzed. Further analysis was conducted on group B to investigate the postnatal risk factors for BPD within twins. RESULTS: A total of 904 pairs of twins with a gestational age of <34 weeks were included in this study. The multivariate logistic regression analysis showed that compared with group C, birth weight discordance of >25% between the twins was an independent risk factor for BPD in one of the twins (OR=3.370, 95%CI: 1.500-7.568, P<0.05), and high gestational age at birth was a protective factor against BPD (P<0.05). The conditional logistic regression analysis of group B showed that small-for-gestational-age (SGA) birth was an independent risk factor for BPD in individual twins (OR=5.017, 95%CI: 1.040-24.190, P<0.05). CONCLUSIONS: The development of BPD in twin preterm infants is associated with gestational age, birth weight discordance between the twins, and SGA birth.


Assuntos
Displasia Broncopulmonar , Recém-Nascido Prematuro , Gêmeos , Humanos , Displasia Broncopulmonar/etiologia , Displasia Broncopulmonar/epidemiologia , Fatores de Risco , Recém-Nascido , Feminino , Estudos Retrospectivos , Masculino , Idade Gestacional , Peso ao Nascer , Modelos Logísticos
9.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 32(3): 974-978, 2024 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-38926999

RESUMO

In recent years, the importance of long non-coding RNA (lncRNA) in acute myeloid leukemia (AML) has attracted wide attention. Among them, lncRNAs that play a role in promoting cancer mainly include HOTAIR, UCA1, H19, ITGB2-AS1 and some genes of SNHG family, while in tumor suppression mainly include H22954, NEAT1, SNHG4, LINC01128 , etc. This article reviews the role of lncRNAs in the occurrence and development of AML, as well as those related to AML resistance and prognosis assessment, so as to provide a theoretical basis for the diagnosis and prognosis analysis of AML.


Assuntos
Leucemia Mieloide Aguda , RNA Longo não Codificante , RNA Longo não Codificante/genética , Humanos , Leucemia Mieloide Aguda/genética , Prognóstico
10.
Int J Surg ; 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38913440

RESUMO

BACKGROUND: Visceral pain occurs commonly following thoracic surgery, but an effective method to relieve visceral pain in thoracic surgery remains controversial. We test the effect of stellate ganglion blocks (SGB) on perioperative visceral pain following video-assisted thoracoscopic surgery (VATS). METHODS: A prospective, randomized, controlled trial enrolled 77 elderly patients undergoing VATS. Patients were randomized to SGB followed by modified intercostal nerve block (Group S, n=37); or modified intercostal nerve block only (Group C, n=40). Remifentanil 0.02-0.2 µg·kg-1·min-1 was titrated to keep pain threshold index values between 40-65 and maintain mean arterial pressure or heart rate values around 20% of baseline values. Patient-controlled intravenous analgesia with sufentanil was used in the postoperative period. The co-primary outcomes were the perioperative cumulative opioid consumption and pain scores on movement at 24 h after surgery. RESULTS: Compared with control group, SGB greatly reduced the intraoperative remifentanil consumption[300.00(235.00-450.00)µg versus 710.00(500.00-915.00)µg; P<0.01], with no difference in cumulative sufentanil consumption to 48h post-surgery. There was a statistically significant difference in pain scores on movement at 24h between groups [4.00(3.00-4.00) versus 4.00(3.25-5.00); P=0.01]. Further exploratory analyses showed significant difference for intra-chest pain on movement at 24h [3.00(2.00-3.00) versus 3.00(2.25-4.00); P=0.01]. No significant difference was observed in nausea/vomiting, time to pass flatus and postoperative length of stay. CONCLUSION: Preoperative stellate ganglion blocks for elderly patients could effectively blunt intraoperative visceral stress and reduce postoperative visceral pain extending 24 h after VATS. This initial finding deserve further investigation.

11.
Adv Mater ; : e2401299, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38837520

RESUMO

Thermal insulation under extreme conditions requires the materials to be capable of withstanding complex thermo-mechanical stress, significant gradient temperature transition, and high-frequency thermal shock. The excellent structural and functional properties of ceramic aerogels make them attractive for thermal insulation. However, in extremely high-temperature environments (above 1500 °C), they typically exhibit limited insulation capacity and thermo-mechanical stability, which may lead to catastrophic accidents, and this problem is never effectively addressed. Here, a novel ceramic meta-aerogel constructed from a crosslinked nanofiber network using a reaction electrospinning strategy, which ensures excellent thermo-mechanical stability and superinsulation under extreme conditions, is designed. The ceramic meta-aerogel has an ultralow thermal conductivity of 0.027 W m-1 k-1, and the cold surface temperature is only 303 °C in a 1700 °C high-temperature environment. After undergoing a significant gradient temperature transition from liquid nitrogen to 1700 °C flame burning, the ceramic meta-aerogel can still withstand thousands of shears, flexures, compressions, and other complex forms of mechanical action without structural collapse. This work provides a new insight for developing ceramic aerogels that can be used for a long period in extremely high-temperature environments.

12.
Virulence ; 15(1): 2350892, 2024 12.
Artigo em Inglês | MEDLINE | ID: mdl-38745370

RESUMO

The evasive tactics of Treponema pallidum pose a major challenge in combating and eradicating syphilis. Natural killer (NK) cells mediate important effector functions in the control of pathogenic infection, preferentially eliminating targets with low or no expression of major histocompatibility complex (MHC) class I. To clarify T. pallidum's mechanisms in evading NK-mediated immunosurveillance, experiments were performed to explore the cross-talk relations among T. pallidum, NK cells, and platelets. T. pallidum adhered to, activated, and promoted particle secretion of platelets. After preincubation with T. pallidum, platelets expressed and secreted high levels of MHC class I, subsequently transferring them to the surface of T. pallidum, potentially inducing an immune phenotype characterized by the "pseudo-expression" of MHC class I on the surface of T. pallidum (hereafter referred to a "pseudo-expression" of MHC class I). The polA mRNA assay showed that platelet-preincubated T. pallidum group exhibited a significantly higher copy number of polA transcript than the T. pallidum group. The survival rate of T. pallidum mirrored that of polA mRNA, indicating that preincubation of T. pallidum with platelets attenuated NK cell lethality. Platelets pseudo-expressed the MHC class I ligand on the T. pallidum surface, facilitating binding to killer cell immunoglobulin-like receptors with two immunoglobulin domains and long cytoplasmic tail 3 (KIR2DL3) on NK cells and initiating dephosphorylation of Vav1 and phosphorylation of Crk, ultimately attenuating NK cell lethality. Our findings elucidate the mechanism by which platelets transfer MHC class I to the T. pallidum surface to evade NK cell immune clearance.


Assuntos
Plaquetas , Antígenos de Histocompatibilidade Classe I , Células Matadoras Naturais , Sífilis , Treponema pallidum , Células Matadoras Naturais/imunologia , Treponema pallidum/imunologia , Treponema pallidum/genética , Humanos , Plaquetas/imunologia , Plaquetas/microbiologia , Antígenos de Histocompatibilidade Classe I/imunologia , Sífilis/imunologia , Sífilis/microbiologia , Evasão da Resposta Imune
13.
JBI Evid Implement ; 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38721758

RESUMO

INTRODUCTION: Peripherally-inserted venous catheters (PIVC) are essential for cancer patients to receive treatment. Phlebitis is a major complication of PIVC. Currently, nurses' assessment of phlebitis mainly involves visual inspection. However, the latest literature suggests palpation for tenderness to promote the early detection of phlebitis. OBJECTIVES: This project evaluated the effectiveness of a bundle approach to increase nurses' compliance with PIVC site assessment to promote early detection of phlebitis (grade 2 and above). METHODS: The JBI Evidence Implementation Framework was used to conduct this project in a 28-bed hematology-oncology ward in a Singapore hospital. The bundle approach used in this project consisted of a training presentation, medical mannequin, and phlebitis scale card. The rate of nurses' compliance with best practice for PIVC site assessment was measured at 1 month and 6 months post-implementation. The incidence of phlebitis was monitored up until 12 months post-implementation. RESULTS: Baseline data indicated that only 18.75% (3 out of 16) nurses palpated for tenderness when assessing for phlebitis. Data at 1 month and 6 months post-implementation reported sustained high compliance rates of 85.71% (24 out of 28) and 89.29% (25 out of 28), respectively. Late detection of phlebitis was reduced by 66% (from three cases to one case) at 6 months post-implementation, and no patients required invasive interventions. CONCLUSIONS: The bundle approach used in this project facilitated early detection of phlebitis following the inclusion of palpation into nurses' assessment for phlebitis. SPANISH ABSTRACT: http://links.lww.com/IJEBH/A204.

14.
Acta Pharmacol Sin ; 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38760544

RESUMO

Cardiac fibrosis is a detrimental pathological process, which constitutes the key factor for adverse cardiac structural remodeling leading to heart failure and other critical conditions. Circular RNAs (circRNAs) have emerged as important regulators of various cardiovascular diseases. It is known that several circRNAs regulate gene expression and pathological processes by binding miRNAs. In this study we investigated whether a novel circRNA, named circNSD1, and miR-429-3p formed an axis that controls cardiac fibrosis. We established a mouse model of myocardial infarction (MI) for in vivo studies and a cellular model of cardiac fibrogenesis in primary cultured mouse cardiac fibroblasts treated with TGF-ß1. We showed that miR-429-3p was markedly downregulated in the cardiac fibrosis models. Through gain- and loss-of-function studies we confirmed miR-429-3p as a negative regulator of cardiac fibrosis. In searching for the upstream regulator of miR-429-3p, we identified circNSD1 that we subsequently demonstrated as an endogenous sponge of miR-429-3p. In MI mice, knockdown of circNSD1 alleviated cardiac fibrosis. Moreover, silence of human circNSD1 suppressed the proliferation and collagen production in human cardiac fibroblasts in vitro. We revealed that circNSD1 directly bound miR-429-3p, thereby upregulating SULF1 expression and activating the Wnt/ß-catenin pathway. Collectively, circNSD1 may be a novel target for the treatment of cardiac fibrosis and associated cardiac disease.

15.
Bioconjug Chem ; 35(4): 540-550, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38557019

RESUMO

Ultrasmall Au25(MPA)18 clusters show great potential in biocatalysts and bioimaging due to their well-defined, tunable structure and properties. Hence, in vivo pharmacokinetics and toxicity of Au nanoclusters (Au NCs) are very important for clinical translation, especially at high dosages. Herein, the in vivo hematological, tissue, and neurological effects following exposure to Au NCs (300 and 500 mg kg-1) were investigated, in which the concentration is 10 times higher than in therapeutic use. The biochemical and hematological parameters of the injected Au NCs were within normal limits, even at the ultrahigh level of 500 mg kg-1. Meanwhile, no histopathological changes were observed in the Au NC group, and immunofluorescence staining showed no obvious lesions in the major organs. Furthermore, real-time near-infrared-II (NIR-II) imaging showed that most of the Au25(MPA)18 and Au24Zn1(MPA)18 can be metabolized via the kidney. The results demonstrated that Au NCs exhibit good biosafety by evaluating the manifestation of toxic effects on major organs at ultrahigh doses, providing reliable data for their application in biomedicine.


Assuntos
Ouro , Nanopartículas Metálicas , Ouro/toxicidade , Ouro/química , Nanopartículas Metálicas/toxicidade , Nanopartículas Metálicas/química
16.
Nano Lett ; 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38619329

RESUMO

Excessive accumulation of reduced nicotinamide adenine dinucleotide (NADH) within biological organisms is closely associated with many diseases. It remains a challenge to efficiently convert superfluous and detrimental NADH to NAD+. NADH oxidase (NOX) is a crucial oxidoreductase that catalyzes the oxidation of NADH to NAD+. Herein, M1M2 (Mi=V/Mn/Fe/Co/Cu/Mo/Rh/Ru/Pd, i = 1 or 2) mated-atom nanozymes (MANs) are designed by mimicking natural enzymes with polymetallic active centers. Excitingly, RhCo MAN possesses excellent and sustainable NOX-like activity, with Km-NADH (16.11 µM) being lower than that of NOX-mimics reported so far. Thus, RhCo MAN can significantly promote the regeneration of NAD+ and regulate macrophage polarization toward the M2 phenotype through down-regulation of TLR4 expression, which may help to recover skin regeneration. However, RhRu MAN with peroxidase-like activity and RhMn MAN with superoxide dismutase-like activity exhibit little modulating effects on eczema. This work provides a new strategy to inhibit skin inflammation and promote skin regeneration.

17.
J Colloid Interface Sci ; 667: 414-424, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38640660

RESUMO

The electrolysis of seawater for hydrogen production holds promise as a sustainable technology for energy generation. Developing water-splitting catalysts with low overpotential and stable operation in seawater is essential. In this study, we employed a hydrothermal method to synthesize NiMoWOX microrods (NiMoWOX@NF). Subsequently, an annealing process yielded a composite N-doped carbon-coated Ni3N/MoO2/WO2 nanorods (NC@Ni3N/MoO2/WO2@NF), preserving the ultrahigh-specific surface area of the original structure. A two-electrode electrolytic cell was assembled using NC@Ni3N/MoO2/WO2@NF as the cathode and NiMoWOX@NF as the anode, demonstrating exceptional performance in seawater splitting. The cell operated at a voltage of 1.51 V with a current density of 100 mA·cm-2 in an alkaline seawater solution. Furthermore, the NC@Ni3N/MoO2/WO2@NF || NiMoWOX@NF electrolytic cell exhibited remarkable stability, running continuously for over 120 h at a current of 1100 mA·cm-2 without any observable delay. These experimental results are corroborated by density functional theory calculations. The NC@Ni3N/MoO2/WO2@NF || NiMoWOX@NF electrolyzer emerges as a promising option for industrial-scale hydrogen production through seawater electrolysis.

18.
Polymers (Basel) ; 16(5)2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38475262

RESUMO

A family of pyridine-oxazoline-ligated cobalt complexes L2CoCl23a-h were synthesized and characterized. Determined via single-crystal X-ray diffraction, complexes 3a and 3d, ligated by two ligands, displayed a distorted tetrahedral coordination of a cobalt center. The X-ray structure indicated the pyridine-oxazoline ligands acted as unusual mono-dentate ligands by coordinating only to Noxazoline. Upon activation with AlEt2Cl (diethylaluminum chloride), these cobalt complexes all exhibited high catalytic activity (up to 2.5 × 106 g·molCo-1·h-1), affording cis-1,4-co-3,4-polyisoprene with molecular weights of 4.4-176 kg mol-1 and a narrow Ð of 1.79-3.42, suggesting a single-site nature of the active sites. The structure of cobalt catalysts and reaction parameters, especially co-catalysts and the reaction temperature, all have significant influence on the polymerization activity but not on the microstructure of polyisoprene.

19.
Int J Biol Sci ; 20(5): 1652-1668, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38481812

RESUMO

Liquid-liquid phase separation (LLPS) is a physiological phenomenon that parallels the mixing of oil and water, giving rise to compartments with diverse physical properties. Biomolecular condensates, arising from LLPS, serve as critical regulators of gene expression and control, with a particular significance in the context of malignant tumors. Recent investigations have unveiled the intimate connection between LLPS and cancer, a nexus that profoundly impacts various facets of cancer progression, including DNA repair, transcriptional regulation, oncogene expression, and the formation of critical membraneless organelles within the cancer microenvironment. This review provides a comprehensive account of the evolution of LLPS from the molecular to the pathological level. We explore the mechanisms by through which biomolecular condensates govern diverse cellular physiological processes, encompassing gene expression, transcriptional control, signal transduction, and responses to environmental stressors. Furthermore, we concentrate on potential therapeutic targets and the development of small-molecule inhibitors associated with LLPS in prevalent clinical malignancies. Understanding the role of LLPS and its interplay within the tumor milieu holds promise for enhancing cancer treatment strategies, particularly in overcoming drug resistance challenges. These insights offer innovative perspectives and support for advancing cancer therapy.


Assuntos
Neoplasias , Separação de Fases , Humanos , Neoplasias/genética , Neoplasias/terapia , Reparo do DNA , Junções Comunicantes , Oncogenes , Microambiente Tumoral/genética
20.
Huan Jing Ke Xue ; 45(2): 668-677, 2024 Feb 08.
Artigo em Chinês | MEDLINE | ID: mdl-38471907

RESUMO

To explore the formation mechanism of the ozone (O3) and emission reduction strategy in a northwestern city, an extensive field campaign was conducted in summertime in 2021 in Yining City, in which the 0-D box model incorporating the latest explicit chemical mechanism (MCMv3.3.1) was applied for the first time to quantify the O3-NOx-VOCs sensitivity and formulate a precise O3 control strategy in this city. The results showed that: ① the three indicators ï¼»i.e., O3 formation potential (OFP), ·OH reaction rate (k·OH), and relative incremental reactivity (RIR)] jointly indicated that alkenes, oxygenated volatile organic compounds (OVOCs), and aromatics were the highest contributors among anthropogenic volatile organic compounds (AVOC) to O3 formation, and the contribution of biogenic volatile organic compounds (BVOC) also could not be ignored. Additionally, the results based on RIR calculation implied that that the acetaldehyde, ethylene, and propylene were the most sensitive individual VOCs species in Yining City. ② The in-situ photochemical O3 variations were primarily influenced by the local photochemical production and export process horizontally to downwind areas or vertically to the upper layer, and the reaction pathways of HO2·+ NO and ·OH + NO2 contributed the most to the gross Ox photochemical production (60%) and photochemical destruction production (53%), respectively. Hence, the reduction in local emissions for O3 precursors was more essential to alleviate O3 pollution in this city. ③ The outcome based on RIR(NOx) / RIR(AVOC) and EKMA jointly suggested that the photochemical regime in this city can be considered a transitional regime that was also nearly a VOCs-limited regime. Detailed mechanism modeling based on multiple scenarios further suggested that the NOx and VOCs synergic emission reduction strategies was helpful to alleviate O3 pollution. These results are useful to provide policy-related guidance for other cities facing similar O3 pollution in northwest China.

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