Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 151
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
Small ; : e2400965, 2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38506595

RESUMEN

Nanostructured metal hydrides with unique morphology and improved hydrogen storage properties have attracted intense interests. However, the study of the growth process of highly active borohydrides remains challenging. Herein, for the first time the synthesis of LiBH4 nanorods through a hydrogen-assisted one-pot solvothermal reaction is reported. Reaction of n-butyl lithium with triethylamine borane in n-hexane under 50 bar of H2 at 40-100 °C gives rise to the formation of the [100]-oriented LiBH4 nanorods with 500-800 nm in diameter, whose growth is driven by orientated attachment and ligand adsorption. The unique morphology enables the LiBH4 nanorods to release hydrogen from ≈184 °C, 94 °C lower than the commercial sample (≈278 °C). Hydrogen release amounts to 13 wt% within 40 min at 450 °C with a stable cyclability, remarkably superior to the commercial LiBH4 (≈9.1 wt%). More importantly, up to 180 °C reduction in the onset temperature of hydrogenation is successfully attained by the nanorod sample with respect to the commercial counterpart. The LiBH4 nanorods show no foaming during dehydrogenation, which improves the hydrogen cycling performance. The new approach will shed light on the preparation of nanostructured metal borohydrides as advanced functional materials.

2.
Immunity ; 42(4): 640-53, 2015 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-25862090

RESUMEN

Acute lung injury (ALI) remains a serious health issue with little improvement in our understanding of the pathophysiology and therapeutic approaches. We investigated the mechanism that lipopolysaccharide (LPS) induces early neutrophil recruitment to lungs and increases pulmonary vascular permeability during ALI. Intratracheal LPS induced release of pro-interleukin-1α (IL-1α) from necrotic alveolar macrophages (AM), which activated endothelial cells (EC) to induce vascular leakage via loss of vascular endothelial (VE)-cadherin. LPS triggered the AM purinergic receptor P2X7(R) to induce Ca(2+) influx and ATP depletion, which led to necrosis. P2X7R deficiency significantly reduced necrotic death of AM and release of pro-IL-1α into the lung. CD14 was required for LPS binding to P2X7R, as CD14 neutralization significantly diminished LPS induced necrotic death of AM and pro-IL-1α release. These results demonstrate a key role for pro-IL-1α from necrotic alveolar macrophages in LPS-mediated ALI, as a critical initiator of increased vascular permeability and early neutrophil infiltration.


Asunto(s)
Interleucina-1alfa/inmunología , Receptores de Lipopolisacáridos/inmunología , Lipopolisacáridos/farmacología , Macrófagos Alveolares/efectos de los fármacos , Receptores Purinérgicos P2X7/inmunología , Lesión Pulmonar Aguda/inducido químicamente , Lesión Pulmonar Aguda/inmunología , Lesión Pulmonar Aguda/patología , Adenosina Trifosfato/metabolismo , Animales , Cadherinas/genética , Cadherinas/inmunología , Calcio/metabolismo , Permeabilidad Capilar/inmunología , Células Endoteliales/efectos de los fármacos , Células Endoteliales/inmunología , Células Endoteliales/patología , Regulación de la Expresión Génica , Células HEK293 , Humanos , Interleucina-1alfa/genética , Intubación Intratraqueal , Receptores de Lipopolisacáridos/genética , Pulmón/efectos de los fármacos , Pulmón/inmunología , Pulmón/patología , Macrófagos Alveolares/inmunología , Macrófagos Alveolares/patología , Ratones , Ratones Transgénicos , Necrosis/inducido químicamente , Necrosis/inmunología , Necrosis/patología , Infiltración Neutrófila , Neutrófilos/efectos de los fármacos , Neutrófilos/inmunología , Neutrófilos/patología , Precursores de Proteínas/genética , Precursores de Proteínas/inmunología , Receptores Purinérgicos P2X7/genética , Transducción de Señal
3.
Sensors (Basel) ; 24(6)2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38544103

RESUMEN

We analyze several factors that affect the linear output range of CMOS image sensors, including charge transfer time, reset transistor supply voltage, the capacitance of integration capacitor, the n-well doping of the pinned photodiode (PPD) and the output buffer. The test chips are fabricated with 0.18 µm CMOS image sensor (CIS) process and comprise six channels. Channels B1 and B2 are 10 µm pixels and channels B3-B6 are 20 µm pixels, with corresponding pixel arrays of 1 × 2560 and 1 × 1280 respectively. The floating diffusion (FD) capacitance varies from 10 fF to 23.3 fF, and two different designs were employed for the n-well doping in PPD. The experimental results indicate that optimizing the FD capacitance and PPD design can enhance the linear output range by 37% and 32%, respectively. For larger pixel sizes, extending the transfer gate (TG) sampling time leads to an increase of over 60% in the linear output range. Furthermore, optimizing the design of the output buffer can alleviate restrictions on the linear output range. The lower reset voltage for noise reduction does not exhibit a significant impact on the linear output range. Furthermore, these methods can enhance the linear output range without significantly amplifying the readout noise. These findings indicate that the linear output range of pixels is not only influenced by pixel design but also by operational conditions. Finally, we conducted a detailed analysis of the impact of PPD n-well doping concentration and TG sampling time on the linear output range. This provides designers with a clear understanding of how nonlinearity is introduced into pixels, offering valuable insight in the design of highly linear pixels.

4.
Water Sci Technol ; 89(8): 2132-2148, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38678414

RESUMEN

Given the substantial environmental pollution from industrial expansion, environmental protection has become particularly important. Nowadays, anion exchange membranes (AEMs) are widely used in wastewater treatment. With the use of polyvinyl alcohol (PVA), ethylene-vinyl alcohol (EVOH) copolymer, and methyl iminodiacetic acid (MIDA), a series of cross-linked AEMs were successfully prepared using the solvent casting technique, and the network structure was formed in the membranes due to the cross-linking reaction between PVA/EVOH and MIDA. Fourier transform infrared spectrometer, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy were used to analyze the prepared membranes. At the same time, its comprehensive properties which include water uptake, linear expansion rate, ion exchange capacity, thermal stability, chemical stability, and mechanical stability were thoroughly researched. In addition, diffusion dialysis performance in practical applications was also studied in detail. The acid dialysis coefficient (UH+) ranged from 10.2 to 35.6 × 10-3 m/h. Separation factor (S) value ranged from 25 to 38, which were all larger than that of the commercial membrane DF-120 (UH+: 8.5 × 10-3 m/h, S: 18.5). The prepared membranes had potential application value in acid recovery.


Asunto(s)
Membranas Artificiales , Alcohol Polivinílico , Alcohol Polivinílico/química , Iminoácidos/química , Difusión , Purificación del Agua/métodos , Diálisis/métodos , Intercambio Iónico , Aniones/química , Polivinilos/química
5.
J Transl Med ; 21(1): 417, 2023 06 27.
Artículo en Inglés | MEDLINE | ID: mdl-37370126

RESUMEN

BACKGROUND: The family with sequence similarity 20-member C (FAM20C) kinase, a Golgi casein kinase, which is responsible for phosphorylating the majority of the extracellular phosphoproteins within S-x-E/pS motifs, and is fundamentally associated with multiple biological processes to maintain cell proliferation, biomineralization, migration, adhesion, and phosphate homeostasis. In dissecting how FAM20C regulates downstream molecules and potential mechanisms, however, there are multiple target molecules of FAM20C, particularly many phenomena remain elusive, such as changes in cell-autonomous behaviors, incompatibility in genotypes and phenotypes, and others. METHODS: Here, assay for transposase-accessible chromatin using sequencing (ATAC-seq), RNA sequencing (RNA-seq), proteomics, and phosphoproteomics were performed in Fam20c-dificient osteoblasts and to facilitate an integrated analysis and determine the impact of chromatin accessibility, genomic expression, protein alterations, signaling pathway, and post translational modifcations. RESULTS: By combining ATAC-seq and RNA-seq, we identified TCF4 and Wnt signaling pathway as the key regulators in Fam20c-dificient cells. Further, we showed Calpastatin/Calpain proteolysis system as a novel target axis for FAM20C to regulate cell migration and F-actin cytoskeleton by integrated analysis of proteomics and phosphoproteomics. Furthermore, Calpastatin/Calpain proteolysis system could negatively regulate the Wnt signaling pathway. CONCLUSION: These observations implied that Fam20c knockout osteoblasts would cause cell homeostatic imbalance, involving changes in multiple signaling pathways in the conduction system.


Asunto(s)
Calpaína , Proteínas de la Matriz Extracelular , Proteínas de la Matriz Extracelular/genética , Proteolisis , Calpaína/metabolismo , Movimiento Celular , Homeostasis
6.
Opt Express ; 31(23): 38989-39006, 2023 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-38017989

RESUMEN

Real-time detection, classification and identification of aerosol particles is crucial in various industries and public health areas. In order to circumvent the limitations of existing particle analysis methods for efficient discrimination, we demonstrate a compact digital in-line holographic microscopy platform with an inertial spectrometer for simultaneous measurement of two independent fingerprint parameters at single species level. In particular, by interrogating the particle location and size captured with the platform, particle mass density can be estimated. Furthermore, by employing Monte Carlo fitting to the Lorenz-Mie theory, the refractive index of each particle can also be extracted from the interference patterns. It is demonstrated that the combination of mass density and optical density characterization unambiguously enhances the discriminatory power of the system, especially when dealing with particles that exhibit similar mass densities but distinctive refractive indices or vice versa. This innovative approach represents a significant advancement in particle characterization and composition identification, with potential applications in various industrial, scientific, and research domains. An iOS-based app interface is then customized for wireless controlling of the CMOS imager, image acquisition, reconstruction, and data analysis. The imaging platform proposed in this work has prominent advantages including compactness, accuracy, efficiency, high throughput, and remote sensing capability, which is especially relevant for applications where on-site/remote metrology and identification of particles is required.

7.
Toxicol Appl Pharmacol ; 480: 116747, 2023 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-37935250

RESUMEN

The aryl hydrocarbon receptor (AHR) is a highly conserved pleiotropic transcription factor that senses environmental pollutants, microbial products, and endogenous ligands. The transcriptional targets of AHR include phase I and phase II detoxification enzymes, as well as numerous signaling molecules that affect a wide spectrum of biological and biochemical processes in a manner of cellular context-dependent. In this review, we systematically assess the latest discoveries of AHR in carcinogenesis with an emphasis on its tumor suppressor-like property that represses the expression of genes in oncogenic signaling pathways. Additionally, we outline recent progress in our studies on the interaction among AHR, TGFb and NRF2 in cellular responses to arsenic and malignant transformation. Our findings indicate that AHR antagonized TGFb and NRF2, suggesting that AHR could serve as a potential tumor suppressor in arsenic-induced carcinogenesis. Notably, while AHR can exhibit both oncogenic and tumor-suppressive properties in cancer development and the generation of the cancer stem-like cells (CSCs), the tumor suppressor-like effect of AHR warrants further extensive exploration for the prevention and clinical treatment of cancers.


Asunto(s)
Arsénico , Receptores de Hidrocarburo de Aril , Humanos , Receptores de Hidrocarburo de Aril/metabolismo , Arsénico/toxicidad , Factor 2 Relacionado con NF-E2/metabolismo , Transformación Celular Neoplásica/metabolismo , Carcinogénesis/inducido químicamente , Carcinogénesis/genética , Carcinogénesis/metabolismo
8.
J Org Chem ; 88(1): 442-454, 2023 01 06.
Artículo en Inglés | MEDLINE | ID: mdl-36520642

RESUMEN

Catalytic direct [4 + 2] cycloaddition reactions and Friedel-Crafts reactions of ortho-alkynylnaphthols with benzofurans have been developed, affording functionalized hydrobenzofuro[3,2-b]chromans and hydroarylation products, respectively, in high yields with high chemoselectivity.


Asunto(s)
Benzofuranos , Estructura Molecular , Reacción de Cicloadición , Estereoisomerismo , Catálisis
9.
Nucleic Acids Res ; 49(17): 9938-9952, 2021 09 27.
Artículo en Inglés | MEDLINE | ID: mdl-34428286

RESUMEN

Casposase, a homolog of Cas1 integrase, is encoded by a superfamily of mobile genetic elements known as casposons. While family 2 casposase has been well documented in both function and structure, little is known about the other three casposase families. Here, we studied the family 1 casposase lacking the helix-turn-helix (HTH) domain from Candidatus Nitrosopumilus koreensis AR1 (Ca. N. koreensis). The determinants for integration by Ca. N. koreensis casposase were extensively investigated, and it was found that a 13-bp target site duplication (TSD) sequence, a minimal 3-bp leader and three different nucleotides of the TSD sequences are indispensable for target specific integration. Significantly, the casposase can site-specifically integrate a broad range of terminal inverted repeat (TIR)-derived oligonucleotides ranging from 7-nt to ∼4000-bp, and various oligonucleotides lacking the 5'-TTCTA-3' motif at the 3' end of TIR sequence can be integrated efficiently. Furthermore, similar to some Cas1 homologs, the casposase utilizes a 5'-ATAA-3' motif in the TSD as a molecular ruler to dictate nucleophilic attack at 9-bp downstream of the end of the ruler during the spacer-side integration. By characterizing the family 1 Ca. N. koreensis casposase, we have extended our understanding on mechanistic similarities and evolutionary connections between casposons and the adaptation elements of CRISPR-Cas immunity.


Asunto(s)
Proteínas Asociadas a CRISPR/genética , Integrasas/genética , Integrasas/metabolismo , Secuencias Repetidas Terminales/genética , Archaea/genética , Sistemas CRISPR-Cas/genética , Elementos Transponibles de ADN/genética , Secuencias Hélice-Giro-Hélice/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Oligonucleótidos/genética
10.
J Biomech Eng ; 145(10)2023 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-37219860

RESUMEN

Canalithiasis is a common vestibular system disorder, which may lead to a specific form of vertigo known as BPPV or top-shelf vertigo. In this paper, based on the actual geometric parameters of the human semicircular canal, we designed a four-fold in vitro one-dimensional semicircular canal model using technologies such as three-dimensional printing, image processing, and target tracking. We investigated the essential characteristics of the semicircular canal, such as the time constant of the cupula and the relationship between the number, density, and size of the canalith and the cupular deformation during canalith settlement. The results showed a linear relationship between the number and size of the canalith and the amount of cupular deformation. We also found that when the number of canaliths reached a particular scale, the interaction between the canaliths exerted an additional disturbance on the cupular deformation ("Z" twist). In addition, we explored the latency time of the cupula during canalith settlement. Finally, we verified that the canaliths had little effect on the frequency characteristics of the semicircular canal by a sinusoidal swing experiment. All the results validate the reliability of our 4-fold in vitro one-dimensional semicircular canal model.


Asunto(s)
Canales Semicirculares , Vértigo , Humanos , Reproducibilidad de los Resultados
11.
Nano Lett ; 22(18): 7651-7658, 2022 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-36066512

RESUMEN

The metal-intercalated bilayer graphene has a flat band with a high density of states near the Fermi energy and thus is anticipated to exhibit an enhanced strong correlation effect and associated fascinating phenomena, including superconductivity. By using a self-developed multifunctional scanning tunneling microscope, we succeeded in observing the superconducting energy gap and diamagnetic response of a Ca-intercalated bilayer graphene below a critical temperature of 8.83 K. The revealed high value of gap ratio, 2Δ/kBTc ≈ 5.0, indicates a strong coupling superconductivity, while the variation of penetration depth with temperature and magnetic field indicates an isotropic s-wave superconductor. These results provide crucial experimental clues for understanding the origin and mechanism of superconductivity in carrier-doped graphene.

12.
Int J Mol Sci ; 24(15)2023 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-37569704

RESUMEN

This study aimed to develop extended-release tablets containing 25 mg IMM-H014, an original drug formulated by a direct powder pressing method based on pharmaceutical-grade hydrophilic matrix polymers such as hydroxypropyl methylcellulose, to establish an in vitro-in vivo correlation (IVIVC) to predict bioavailability. The tablets' mechanical properties and in vitro and in vivo performance were studied. The formulation was optimized using a single-factor experiment and the reproducibility was confirmed. The in vitro dissolution profiles of the tablet were determined in five dissolution media, in which the drug released from the hydrophilic tablets followed the Ritger-Peppas model kinetics in 0.01 N HCl medium for the first 2 h, and in phosphate-buffered saline medium (pH 7.5) for a further 24 h. Accelerated stability studies (40 °C, 75% relative humidity) proved that the optimal formulation was stable for 6 months. The in vivo pharmacokinetics study in beagle dogs showed that compared to the IMM-H014 immediate release preparation, the maximum plasma concentration of the extended-release (ER) preparation was significantly decreased, while the maximum time to peak and mean residence time were significantly prolonged. The relative bioavailability was 97.9% based on the area under curve, indicating that the optimal formulation has an obvious ER profile, and a good IVIVC was established, which could be used to predict in vivo pharmacokinetics based on the formulation composition.


Asunto(s)
Hepatopatías , Animales , Perros , Reproducibilidad de los Resultados , Comprimidos/farmacocinética , Preparaciones de Acción Retardada/química , Disponibilidad Biológica , Solubilidad
13.
Int J Mol Sci ; 24(24)2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-38139337

RESUMEN

An accurate, rapid, and selective quantitative nuclear magnetic resonance method was developed and validated to assess the purity of IMM-H014, a novel drug for the treatment of metabolic-associated fatty liver disease (MAFLD), and four related substances (impurities I, II, III, and IV). In this study, we obtained spectra of IMM--H014 and related substances in deuterated chloroform using dimethyl terephthalate (DMT) as the internal standard reference. Quantification was performed using the 1H resonance signals at δ 8.13 ppm for DMT and δ 6.5-7.5 ppm for IMM-H014 and its related substances. Several key experimental parameters were investigated and optimized, such as pulse angle and relaxation delay. Methodology validation was conducted based on the International Council for Harmonization guidelines and verified with satisfactory specificity, precision, linearity, accuracy, robustness, and stability. In addition, the calibration results of the samples were consistent with those obtained from the mass balance method. Thus, this research provides a reliable and practical protocol for purity analysis of IMM-H014 and its critical impurities and contributes to subsequent clinical quality control research.


Asunto(s)
Hepatopatías , Humanos , Espectroscopía de Resonancia Magnética/métodos , Control de Calidad , Calibración
14.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 40(4): 820-828, 2023 Aug 25.
Artículo en Zh | MEDLINE | ID: mdl-37666775

RESUMEN

Attention level evaluation refers to the evaluation of people's attention level through observation or experimental testing, and its research results have great application value in education and teaching, intelligent driving, medical health and other fields. With its objective reliability and security, electroencephalogram signals have become one of the most important technical means to analyze and express attention level. At present, there is little review literature that comprehensively summarize the application of electroencephalogram signals in the field of attention evaluation. To this end, this paper first summarizes the research progress on attention evaluation; then the important methods for electroencephalogram attention evaluation are analyzed, including data preprocessing, feature extraction and selection, attention evaluation methods, etc.; finally, the shortcomings of the current development in the field of electroencephalogram attention evaluation are discussed, and the future development trend is prospected, to provide research references for researchers in related fields.


Asunto(s)
Electroencefalografía , Humanos , Reproducibilidad de los Resultados
15.
Semin Cancer Biol ; 76: 310-318, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-33823236

RESUMEN

Environmental exposure to arsenic, a well-established carcinogen linked to a number of human cancers, is a public health concern in many areas of the world. Despite extensive studies on the molecular mechanisms of arsenic-induced carcinogenesis, how initial cellular responses, such as activation of stress kinases and the generation of reactive oxygen species, converge to affect the transcriptional and/or epigenetic reprogramming required for the malignant transformation of normal cells or normal stem cells remains to be elucidated. In this review, we discuss some recent discoveries showing how the transcription factor NRF2 and an epigenetic regulator, MDIG, contribute to the arsenic-induced generation of cancer stem-like cells (CSCs) as determined by applying CRISPR-Cas9 gene editing and chromosome immunoprecipitation followed by DNA sequencing (ChIP-seq).


Asunto(s)
Arsénico/efectos adversos , Transformación Celular Neoplásica/inducido químicamente , Epigénesis Genética/fisiología , Histona Demetilasas/metabolismo , Factor 2 Relacionado con NF-E2/metabolismo , Células Madre Neoplásicas/patología , Animales , Dioxigenasas/metabolismo , Humanos , Proteínas Nucleares/metabolismo , Transcripción Genética
16.
Toxicol Appl Pharmacol ; 436: 115884, 2022 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-35031324

RESUMEN

Arsenic (As3+), a metalloid abundant in environment, is classified as a group I carcinogen associated with several common human cancers, including cancers in lung, skin, bladder, liver, and prostate (Wei et al., 2019). The mechanisms of As3+-induced carcinogenesis had been extensively studied, and different mechanisms might be involved in different types of cancer (Wei et al., 2019). Recent studies showed that exposure to a high dose of arsenic is able to induce lung cancer. Meanwhile, prolonged exposure to a low concentration of arsenic can increase the risk of lung cancer also (Liao et al., 2009; Fernández et al., 2012). Emerging evidence indicated that prolonged exposure to arsenic promotes malignant transformation and some of the transformed cells have cancer-stem-like properties (Ngalame et al., 2014). In the present report, we revealed that exposure to As3+ for short time period inhibited tyrosine-705 phosphorylation of signal transducer and activator of transcription 3 (pSTAT3Y705) and induced Src homology region 2 domain-containing phosphatase-1 (SHP-1) in bronchial epithelial cell line, BEAS-2B. In addition, we found that long term exposure of the cells to As3+ activates phosphorylation of STAT3 at serine 727 (pSTAT3S727) as well as pSTAT3Y705. Moreover, As3+ is able to induce the expression of miRNA-21 (miR-21) and decrease the expression of PDCD4. Taken together, our data suggest that activation of STAT3 and induction of miR-21 are important contributing factors to the reduced expression of PDCD4, which may play significant role in As3+-induced transformation of BEAS-2B cells.


Asunto(s)
Arsénico/efectos adversos , Bronquios/efectos de los fármacos , Transformación Celular Neoplásica/efectos de los fármacos , Células Epiteliales/efectos de los fármacos , Factor de Transcripción STAT3/genética , Transducción de Señal/efectos de los fármacos , Proteínas Reguladoras de la Apoptosis/genética , Bronquios/metabolismo , Carcinogénesis/inducido químicamente , Carcinogénesis/genética , Transformación Celular Neoplásica/genética , Células Cultivadas , Células Epiteliales/metabolismo , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/genética , Humanos , Neoplasias Pulmonares/inducido químicamente , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Fosforilación/efectos de los fármacos , Fosforilación/genética , Proteínas de Unión al ARN/genética , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal/genética
17.
J Org Chem ; 87(5): 2853-2863, 2022 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-35077160

RESUMEN

Herein we report a chiral phosphoric acid-catalyzed intermolecular C2 Friedel-Crafts alkylation reaction between ortho-alkynylnaphthols and various 3-substituted indoles, affording axially chiral alkenes with up to 93% yields (E/Z > 20:1) and up to 98% ee under mild reaction condition. Other substituted indole derivatives could be also tolerated in this system, giving the corresponding axially chiral alkenes with high yields and in excellent enantioselectivity.

18.
J Org Chem ; 87(14): 9100-9111, 2022 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-35749311

RESUMEN

Herein, we report chiral strong Brønsted acid-catalyzed enantioselective Friedel-Crafts reaction of 2-alkynyphenols with aromatic ethers. The reaction affords the corresponding axially chiral styrenes in up to 91% yield and 97% ee.

19.
Org Biomol Chem ; 20(4): 870-876, 2022 01 26.
Artículo en Inglés | MEDLINE | ID: mdl-35006233

RESUMEN

Seventeen C20-O-alkyl/benzyl oxime derivatives were synthesized by a concise and effective method. Most of these derivatives showed tens to several hundred nanomolar IC50 values against HT-29 colorectal, HGC-27 gastric and MDA-MB-231 breast cancer cells, whose antiproliferative activity is 15-240 fold better than that of salinomycin. The C20-oxime etherified derivatives can coordinate potassium ions, and further adjust the cytosolic Ca2+ concentrations in HT-29 cells. The significant improvement of the potency should be attributed to the better ion binding and transport ability of the modified derivatives. In addition, the C20-O-alkyl/benzyl oxime derivatives showed much better selectivity indexes (SI) than salinomycin, indicating that they present lower neurotoxic risk.


Asunto(s)
Antineoplásicos/farmacología , Oximas/farmacología , Piranos/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Modelos Moleculares , Conformación Molecular , Oximas/síntesis química , Oximas/química , Piranos/síntesis química , Piranos/química
20.
Bioorg Med Chem ; 59: 116676, 2022 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-35220163

RESUMEN

We report herein the design, synthesis, and structure-activity relationship studies of pleuromutilin derivatives containing urea/thiourea functionalities. The antibacterial activities of these new pleuromutilin derivatives were evaluated in vitro against Gram-positive pathogens (GPPs) (Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecium) and Mycoplasma pneumoniae by the broth dilution method. Most of the targeted compounds exhibit good potency in inhibiting the growth of pathogens including Methicillin-susceptible S. aureus (MSSA, ATCC29213, MIC: 0.0625-16 µg/mL), Methicillin-resistant S. aureus (MRSA, ATCC43300, MIC: 0.125-16 µg/mL) and M. pneumoniae (ATCC15531 MIC: 0.125-1 µg/mL, ATCC29342 MIC: 0.0625-0.25 µg/mL and drug resistant strain MIC: 0.5-2 µg/mL). In particular, the compounds 6m and 6n containing phenyl-urea group showed excellent activity with the MIC value less than 0.0625 µg/mL against S. aureus ATCC29213. The compound 6h exhibited better activity than tiamulin against Methicillin-resistant S. aureus ATCC43300.


Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Staphylococcus aureus , Antibacterianos/farmacología , Diterpenos , Pruebas de Sensibilidad Microbiana , Compuestos Policíclicos , Urea , Pleuromutilinas
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA