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Drug resistance is a serious problem for gefitinib in the treatment of lung cancer. Ginsenoside CK, a metabolite of diol ginsenosides, have many excellent pharmacological activities, but whether ginsenoside CK can overcome gefitinib resistance remains unclear. In our study, the sensitizing activity of ginsenoside CK on gefitinib-resistant non-small cell lung cancer (NSCLC) in vitro and in vivo was investigated. Ginsenoside CK was confirmed to enhance the anti-proliferation, pro-apoptotic and anti-migration effects of gefitinib in primary and acquired resistant NSCLC. Furthermore, the combined administration of CK and gefitinib effectively promoted the sensitivity of lung cancer xenograft to gefitinib in vivo, and the tumor inhibition rate reached 70.97% (vs. gefitinib monotherapy 32.65%). Subsequently, tubule formation experiment and western blot results showed that co-treatment of ginsenoside CK inhibited the angiogenesis ability of HUVEC cells, and inhibited the expression of HIF-1α, VEGF, FGF and MMP2/9. More interestingly, ginsenoside CK co-treatment enhanced the expression of anti-angiogenic factor PF4, increased pericellular envelope, and promoted the normalization of vascular structure. In conclusion, ginsenoside CK improved the resistance of gefitinib by regulating the balance of angiogenic factors through down-regulating the HIF-1α/VEGF signaling pathway, providing a theoretical basis for improving the clinical efficacy of gefitinib and applying combined strategies to overcome drug resistance.
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Carcinoma de Pulmón de Células no Pequeñas , Resistencia a Antineoplásicos , Sinergismo Farmacológico , Gefitinib , Ginsenósidos , Células Endoteliales de la Vena Umbilical Humana , Subunidad alfa del Factor 1 Inducible por Hipoxia , Neoplasias Pulmonares , Ratones Desnudos , Factor A de Crecimiento Endotelial Vascular , Gefitinib/farmacología , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Ginsenósidos/farmacología , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/patología , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Animales , Resistencia a Antineoplásicos/efectos de los fármacos , Factor A de Crecimiento Endotelial Vascular/metabolismo , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto , Antineoplásicos/farmacología , Ratones , Ratones Endogámicos BALB C , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Células A549 , Neovascularización Patológica/tratamiento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , FemeninoRESUMEN
Four new compounds, including one drimane sesquiterpene lactone (1), one isocoumarin (2), one coumarin (3), and a new natural product (4), as well as fourteen known compounds were obtained from a deep-sea derived Cladosporium sp. SCSIO 41318. The structures of the new compounds were determined using extensive NMR and HRESIMS spectroscopic analysis, electronic circular dichroism calculations, and single-crystal X-ray diffraction measurements. Biological assays showed that compounds (1, 6, 7, 9-12, 14, 15, 17, 18) exhibited varying degrees of antimicrobial activity against the tested human pathogenic bacteria and plant pathogenic fungi. Besides, penicitrinone A (11) and penicitrinol A (12) displayed weak antitumor activities against the 22Rv1 cell line.
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Electrocatalytic reduction of oxygen (O2 ) to produce hydrogen peroxide (H2 O2 ) frequently suffers from the low activity and poor selectivity of catalysts owing to the lack of systematic strategies. The resulting enhancement to enable the further design of a new bimetallic catalyst with the synergistic interplay, as exemplified by Cu-Pb catalyst for two-electron oxygen reduction reaction (2e- ORR), is reported here. Critically, in-depth evidence, including density functional theory (DFT) calculations, electrochemical signals, in-situ Raman, and H2 O2 -proof work, allude to a catalytic favor to the 2e- ORR of Cu-Pb.
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Plomo , Oxígeno , Catálisis , Peróxido de HidrógenoRESUMEN
A redox-active metal-organic framework, Cu(I)-TPT, was synthesized by combination of Cu(I), the halogenoid cyanide group (CN), and redox-active organic bridging ligand 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPT) into one single framework. Cu(I)-TPT displays a two-dimensional (2D) plane structure by 1D -Cu(I)-CN- chains connected with TPT ligands. Cu(I)-TPT exhibits intrinsic semiconductive features with a moderate bandgap energy (1.97 eV). Under irradiation, Cu(I)-TPT has an electrical conductivity of 2 × 10-7 S cm-1 in the presence of the sacrificial electron donor ethanol under the ambient test conditions, which is owing to the π-π stacking interactions between TPT moieties, the d-π conjugation between the Cu(I) ion and the CN ligands, and the permanent microporosity. Cu(I)-TPT displayed highly efficient hole-electron separation and ordered electron transfer, which is beneficial for the photoreduction of nitrobenzene. In addition, Cu(I)-TPT displays high efficiency in carboxylic cyclization of alkynol with CO2 because it possesses highly decentralized Cu(I) catalytic sites to the active C≡C bond of alkynol and affluent N atoms on the 2D sheets to facilitate the trapping and activation of CO2.
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One new citrinin monomer derivative (1), and two new natural products α-pyrone analogues (2a and 2b), were isolated from the sponge derived fungus Penicillium sp. SCSIO 41302. Their structures were determined by extensive spectroscopic analysis, chiral-phase HPLC analysis, modified Mosher's method, ECD calculations, and X-ray single-crystal diffraction. Bioactivity screening showed that compounds 2b and 8 exhibited obvious inhibitory activities against pancreatic lipase and acetyl cholinesterase with IC50 values of 48.5 and 4.8 µM, respectively, which indicated that different chiral center between enantiomers (2a and 2b) might result in different biological activities (IC50 value against PL for 2a >100 µg/ml).
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Productos Biológicos , Citrinina , Penicillium , Productos Biológicos/química , Colinesterasas , Lipasa , Estructura Molecular , Penicillium/química , Pironas/farmacologíaRESUMEN
Three new compounds, including two new 3,4,6-trisubstituted α-pyrone derivatives, chrysopyrones A and B (1 and 2), and one new indolyl diketopiperazine derivative, penilline C (3), along with twelve known compounds (4-15), were isolated and identified from the fungus Penicillium chrysogenum SCSIO 07007, separated from deep-sea hydrothermal vent environment sample collected from the Western Atlantic. Their structures and absolute configurations were determined by extensive spectroscopic analysis and electronic circular dichroism (ECD) calculations. All of the isolated compounds (1-15) were evaluated for their cytotoxic, antibacterial activities and enzyme inhibitory activities against acetylcholinesterase (AChE), α-glycosidase, and protein tyrosine phosphatase 1B (PTP1B). Among them, new compounds chrysopyrones A and B (1 and 2) displayed obvious inhibitory activities against PTP1B with IC50 values of 9.32 and 27.8 µg/mL, respectively. Furthermore, molecular docking was performed to investigate the inside perspective of the action in PTP1B enzyme.
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Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Penicillium chrysogenum/química , Proteína Tirosina Fosfatasa no Receptora Tipo 1/antagonistas & inhibidores , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Antibacterianos/farmacología , Inhibidores Enzimáticos/aislamiento & purificación , Humanos , Simulación del Acoplamiento Molecular , Proteína Tirosina Fosfatasa no Receptora Tipo 1/metabolismo , Pironas/química , Pironas/aislamiento & purificación , Pironas/farmacologíaRESUMEN
Oxidative stress and inflammation play important roles in the pathogenesis of cardiovascular disease (CVD). Oxidative stress-induced desialylation is considered to be a primary step in atherogenic modification, and therefore, the attenuation of oxidative stress and/or inflammatory reactions may ameliorate CVD. In this study, quercetin 7-O-sialic acid (QA) was synthesized aiming to put together the cardiovascular protective effect of quercetin and the recently reported anti-oxidant and anti-atherosclerosis functions of N-acetylneuraminic acid. The biological efficacy of QA was evaluated in vitro in various cellular models. The results demonstrated that 50 µM QA could effectively protect human umbilical vein endothelial cells (HUVEC, EA.hy926) against hydrogen peroxide- or oxidized low-density lipoprotein-induced oxidative damage by reducing the production of reactive oxygen species. QA attenuated hydrogen peroxide-induced desialylation of HUVEC and lipoproteins. QA decreased lipopolysaccharide-induced secretion of tumour necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1), and it significantly reduced the expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, TNF-α and MCP-1. Furthermore, QA effectively promoted cholesterol efflux from Raw 264.7 macrophages to apolipoprotein A-1 and high-density lipoprotein by up-regulating ATP-binding cassette transporter A1 and G1, respectively. Results indicated that the novel compound QA exhibited a better capacity than quercetin for anti-oxidation, anti-inflammation, cholesterol efflux promotion and biomolecule protection against desialylation and therefore could be a candidate compound for the prevention or treatment of CVD.
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Cardiotónicos/química , Cardiotónicos/farmacología , Ácido N-Acetilneuramínico/química , Ácido N-Acetilneuramínico/farmacología , Quercetina/química , Quercetina/farmacología , Transportadoras de Casetes de Unión a ATP/metabolismo , Animales , Apolipoproteína A-I/metabolismo , Aterosclerosis/tratamiento farmacológico , Aterosclerosis/metabolismo , Línea Celular , Quimiocina CCL2/metabolismo , Células Endoteliales de la Vena Umbilical Humana , Humanos , Inflamación/tratamiento farmacológico , Inflamación/metabolismo , Molécula 1 de Adhesión Intercelular/metabolismo , Lipoproteínas LDL/metabolismo , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Ratones , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Molécula 1 de Adhesión Celular Vascular/metabolismoRESUMEN
An ultrathin, lightweight, and wearable Li-O2 battery with a novel segmented structure is first fabricated by employing a "break up the whole into parts" strategy. Superior battery performance including low overpotential, high specific capacity, good rate capability, excellent cycle stability, and high gravimetric/volumetric energy density (294.68 Wh kg-1 /274.06 Wh L-1 ) is successfully achieved even under repeatedly various deformation.
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In this paper, 17 compounds (1-17) were isolated from the leaves of Hemp (Cannabis sativa f. sativa). Among the isolates, two were determined to be new spirans: cannabispirketal (1), and α-cannabispiranol 4'-O-ß-D-glucopyranose (2) by 1D and 2D NMR spectroscopy, LC-MS, and HRESIMS. The known compounds 7, 8, 10, 13, 15, and 16 were isolated from Hemp (C. sativa f. sativa) for the first time. Furthermore, compounds 8 and 13 were isolated from the nature for the first time. All isolated compounds were evaluated for cytotoxicity on different tissue-derived passage cancer cell lines through cell viability and apoptosis assay. Among these compounds, compounds 5, 9 and 16 exhibited a broad-spectrum antitumor effect via inhibiting cell proliferation and promoting apoptosis. These results obtained have provided valuable clues to the understanding of the cytotoxic profile for these isolated compounds from Hemp (C. sativa f. sativa).
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Antineoplásicos Fitogénicos/aislamiento & purificación , Antineoplásicos Fitogénicos/farmacología , Cannabis/química , Medicamentos Herbarios Chinos/aislamiento & purificación , Medicamentos Herbarios Chinos/farmacología , Flavonoides/aislamiento & purificación , Flavonoides/farmacología , Hojas de la Planta/química , Compuestos de Espiro/aislamiento & purificación , Antineoplásicos Fitogénicos/química , Apigenina , Ensayos de Selección de Medicamentos Antitumorales , Medicamentos Herbarios Chinos/química , Flavonas , Flavonoides/química , Humanos , Células MCF-7 , Estructura Molecular , Compuestos de Espiro/químicaRESUMEN
A novel cable-type water-survivable flexible Li-O2 battery is developed with a hydrophobic and free standing gel polymer electrolyte. Superior battery performances are successfully achieved under mechanical twisting, bending, and even immersed in water conditions, showing the high promise to power next-generation versatile flexible electronics.
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Sixteen naturally occurring oleanolic acid saponins and their derivatives were synthesized in an efficient and practical strategy, and their inhibitory activities against α-glucosidase and α-amylase were evaluated in vitro. Among all the compounds, 28-O-monoglucoside 8 exhibited remarkably potent inhibitory activity against α-glucosidase with an IC50 value of 87.3 µM, which was fivefold stronger than that of the antidiabetic acarbose. Based on the preliminary structure-activity relationships, for 28-O-monoglucosides, the presence of a terminal α-l-rhamnopyranosyl residue enhanced the α-glucosidase and α-amylase inhibitory activities. Furthermore, for 3,28-O-bidesmosides, sugar-substituted moieties attached to the C-3 and C-28 positions of the oleanolic acid scaffold are helpful to increase the inhibitory activities against α-amylase and α-glucosidase.
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Antineoplásicos/síntesis química , Antineoplásicos/farmacología , Inhibidores de Glicósido Hidrolasas/síntesis química , Inhibidores de Glicósido Hidrolasas/farmacología , Ácido Oleanólico/síntesis química , Ácido Oleanólico/farmacología , Saponinas/síntesis química , Saponinas/farmacología , alfa-Amilasas/antagonistas & inhibidores , alfa-Glucosidasas/metabolismo , Acarbosa/farmacología , Relación Dosis-Respuesta a Droga , Diseño de Fármacos , Estructura Molecular , Ácido Oleanólico/análogos & derivados , Relación Estructura-Actividad , alfa-Amilasas/metabolismoRESUMEN
It is significant to develop catalysts with high catalytic activity and durability to improve the electrochemical performances of lithium-oxygen batteries (LOBs). While electronic metal-support interaction (EMSI) between metal atoms and support has shown great potential in catalytic field. Hence, to effectively improve the electrochemical performance of LOBs, atomically dispersed Fe modified RuO2 nanoparticles are designed to be loaded on hierarchical porous carbon shells (FeSA -RuO2 /HPCS) based on EMSI criterion. It is revealed that the Ru-O-Fe1 structure is formed between the atomically dispersed Fe atoms and the surrounding Ru sites through electron interaction, and this structure could act as the ultra-high activity driving force center of oxygen reduction/evolution reaction (ORR/OER). Specifically, the Ru-O-Fe1 structure enhances the reaction kinetics of ORR to a certain extent, and optimizes the morphology of discharge products by reducing the adsorption energy of catalyst for O2 and LiO2 ; while during the OER process, the Ru-O-Fe1 structure not only greatly enhances the reaction kinetics of OER, but also catalyzes the efficient decomposition of the discharge products Li2 O2 by the favorable electron transfer between the active sites and the discharge products. Hence, LOBs based on FeSA-RuO2 /HPCS cathodes show an ultra-low over-potential, high discharge capacity and superior durability.
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Flower bud differentiation is of great significance for understanding plant evolution and ecological adaptability. The development of flower buds and mixed buds in the dichasial inflorescence of Geranium koreanum was described in this paper. The morphogenesis, surface structure, and organ morphology at different growth stages of G. koreanum buds were examined in detail using scanning electron microscope and stereo microscope. The development of mixed buds started from the flattened apical meristem. The stipule and leaf primordia arose first. Subsequently, the hemispherical meristem was divided into two hemispheres, forming a terminal bud and floral bud primordia, followed by lateral bud differentiation. The formation of the terminal and lateral buds of G. koreanum was sequential and their differentiation positions were also different. The floral bud primordia would develop into two flower units and four bracts. The primordia of a flower bud first formed the sepal primordia, then the stamen and petal primordia, and finally the pistil primordia. Compared to the stamen primordia, the growth of the petal primordia was slower. Finally, all organs, especially the petals and pistil, grew rapidly. When the pistil and petals exceeded the stamens and the petals changed color, the flower bud was ready to bloom.
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Lung cancer is the malignancy with the highest morbidity and mortality. Additionally, pulmonary inflammatory diseases, such as pneumonia, acute lung injury, chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis (PF), also have high mortality rates and can promote the development and progression of lung cancer. Unfortunately, available treatments for them are limited, so it is critical to search for effective drugs and treatment strategies to protect the lungs. Ginsenosides, the main active components of ginseng, have been shown to have anti-cancer and anti-inflammatory activities. In this paper, we focus on the beneficial effects of ginsenosides on lung diseases and their molecular mechanisms. Firstly, the molecular mechanism of ginsenosides against lung cancer was summarized in detail, mainly from the points of view of proliferation, apoptosis, autophagy, angiogenesis, metastasis, drug resistance and immunity. In in vivo and in vitro lung cancer models, ginsenosides Rg3, Rh2 and CK were reported to have strong anti-lung cancer effects. Then, in the models of pneumonia and acute lung injury, the protective effect of Rb1 was particularly remarkable, followed by Rg3 and Rg1, and its molecular mechanism was mainly associated with targeting NF-κB, Nrf2, MAPK and PI3K/Akt pathways to alleviate inflammation, oxidative stress and apoptosis. Additionally, ginsenosides may also have a potential health-promoting effect in the improvement of COPD, asthma and PF. Furthermore, to overcome the low bioavailability of CK and Rh2, the development of nanoparticles, micelles, liposomes and other nanomedicine delivery systems can significantly improve the efficacy of targeted lung cancer treatment. To conclude, ginsenosides can be used as both anti-lung cancer and lung protective agents or adjuvants and have great potential for future clinical applications.
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Lesión Pulmonar Aguda , Ginsenósidos , Neoplasias Pulmonares , Panax , Neumonía , Enfermedad Pulmonar Obstructiva Crónica , Humanos , Ginsenósidos/farmacología , Ginsenósidos/uso terapéutico , Fosfatidilinositol 3-Quinasas , Neoplasias Pulmonares/tratamiento farmacológico , Pulmón , Neumonía/tratamiento farmacológico , Enfermedad Pulmonar Obstructiva Crónica/tratamiento farmacológico , Lesión Pulmonar Aguda/tratamiento farmacológico , Lesión Pulmonar Aguda/prevención & controlRESUMEN
Gefitinib, as the first-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), has achieved great advances in the treatment of non-small cell lung cancer (NSCLC), but drug resistance will inevitably occur. Therefore, exploring the resistance mechanism of gefitinib and developing new combination treatment strategies are of great importance. In our study, the results showed that selumetinib (AZD6244) synergistically inhibited the proliferation of NSCLC with gefitinib. Selumetinib also enhanced gefitinib-induced apoptosis and migration inhibition ability in gefitinib-resistant lung cancer cell lines. Subsequently, the negative regulation between MIG6 and STAT3 was observed and verified through the STRING database and western blotting assays. Sustained activation of STAT3 was significantly downregulated when co-treatment with selumetinib in gefitinib-resistant cells. However, the downregulation of p-STAT3, resulting from the combination of selumetinib and gefitinib was counteracted by the deletion of MIG6, suggesting that selumetinib enhanced gefitinib sensitivity by regulating MIG6/STAT3 in NSCLC. In contrast, p-STAT3 was further inhibited after treatment with gefitinib and selumetinib when MIG6 was overexpressed. Furthermore, the combined administration of selumetinib and gefitinib effectively promoted the sensitivity of lung cancer xenografts to gefitinib in vivo, and the tumor inhibition rate reached 81.49%, while the tumor inhibition rate of the gefitinib monotherapy group was only 31.95%. Overall, MIG6/STAT3 negative regulation plays an important role in the sustained activation of STAT3 and the resistance to EGFR-TKIs. Our study also suggests that EGFR-TKIs combined with MEK1/2 inhibitors, such as selumetinib, may be beneficial to those NSCLC patients who develop a primary or acquired resistance to EGFR-TKIs, providing theoretical support for combining TKIs and selumetinib in clinical cancer treatment.
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Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Humanos , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Gefitinib/farmacología , Gefitinib/uso terapéutico , Neoplasias Pulmonares/metabolismo , Receptores ErbB/metabolismo , Quinazolinas/farmacología , Quinazolinas/uso terapéutico , Inhibidores de Proteínas Quinasas/farmacología , Apoptosis , Resistencia a Antineoplásicos , Línea Celular Tumoral , Proliferación Celular , Factor de Transcripción STAT3/metabolismoRESUMEN
A plasma grating is formed by two femtosecond filaments, and the influence of probe filament on the plasma grating is shown. By using the plasma grating, the enhancement of the third harmonic (TH) generated from the probe filament is studied, and more than three orders of magnitude enhancement of TH generation is demonstrated as compared with that obtained from a single filament. The dependences of TH generation on the time delay, the spatial period of plasma grating, the relative polarization and the crossing position between the probe beam and the two pump beams are investigated. The spectral broadening of TH generated from the probe filament induced by the interaction between the probe filament and the plasma grating is also studied.
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The first total synthesis of benzophenone O-glycosides (iriflophenone 2-O-α-L-rhamnopyranoside: 1 and aquilarisinin: 2) isolated from the leaves of Aquilaria sinensis and related new derivatives (3-12) was accomplished through suitable protecting group manipulations and glycosylation starting from commercially available L-rhamnose, D-glucose, D-galactose, D-mannose, D-xylose, and 1,3,5-trihydroxybenzene. All synthesized benzophenone O-glycosides were evaluated for their inhibitory activities against α-glucosidase. Of these, benzophenone O-glycosides 4 and 10 exhibited the most potent inhibitory activity in vitro against α-glucosidase with IC(50) values of 168.7 ± 13.9 and 210.1 ± 23.9 µM, respectively, when compared with that of the positive control acarbose with an IC(50) value of 569.3 ± 49.7 µM.
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Benzofenonas/farmacología , Inhibidores de Glicósido Hidrolasas , Glicósidos/farmacología , Thymelaeaceae/química , Benzofenonas/síntesis química , Benzofenonas/química , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Glicósidos/síntesis química , Glicósidos/química , Concentración 50 Inhibidora , Hojas de la Planta , Relación Estructura-ActividadRESUMEN
Ginsenosides, characterized by triterpenoid, are one of the active components of ginseng. Among them, PPD-type ginsenosides have potent and diverse pharmacological activities, while the effective applications and clinical studies are limited by the poor stability, water solubility and oral bioavailability. In this review, we have attempted to demonstrate the structural-activity relationship of chemical modifications on the dammarane-type skeleton and the C-17 side chain, noting that certain structurally modified derivatives exhibit satisfactory pharmacological activity. This review will provide ideas for the design and synthesis of novel PPD derivatives, and valuable help for the further study of PPD derivatives to make it realize clinical application.
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Ginsenósidos , Panax , Ginsenósidos/farmacología , Estructura Molecular , Panax/química , Relación Estructura-ActividadRESUMEN
A major challenge for Li-O2 batteries is to facilely achieve the formation and decomposition of the discharge product Li2O2, and the development of an active and synergistic cathode is of great significance to efficiently accelerate its formation/decomposition kinetics. Herein, a novel strategy is presented by constructing a MnO2-x@CeO2 heterostructure on the porous carbon matrix. When it was used as a cathode for Li-O2 batteries, excellent electrochemical performances, including low overpotential, large discharge capacity, and superior cycling stability were obtained. Series theoretical calculations were conducted to reveal the mechanism for the reversible battery reactions and explain how Li2O2 interacts with the MnO2-x@CeO2 interface. Apart from the electronic ladders formed between MnO2-x 3d and CeO2 4f orbitals, which can act as a highly efficient "electron transfer expressway", the specific adsorption of MnO2-x and CeO2 with Li2O2 molecules contributes to the enhanced anchoring force of Li2O2 and delocalization of the electron cloud on the Li-O bond. Thanks to the constructed heterostructure and synergistic effect, filmlike Li2O2 can be formed through a surface pathway, and when charging, it accelerates the separation of electrons and Li+ in Li2O2, thus achieving fast redox kinetics and low overpotential.
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The main objective of this study is to evaluate highway crash risk and improve the spatial and temporal transferability of crash risk models. The predictive performance is affected by the difficulty of existing models to quantify crash risk from historical traffic flow data at different locations and times and may not fully capture the complex nonlinear relationships between high-dimensional factors in traffic flow states. Oregon US26W freeway data from 2016 and 2017 and I5N freeway data from 2017 were used. Raw detector data collected from two consecutive detector stations upstream-downstream detector stations were converted into 30 traffic variables. The averages, standard deviations, and coefficients of variation were obtained by aggregating traffic values using each lane. Candidate variables for traffic flow were extracted, and the importance of each variable was calculated using LightGBM, which reveals that variable differences between lanes contributed more. The manifold distance was then applied to quantify the crash risk and classify traffic crashes or not. When the manifold distance is 0.4, it could effectively distinguish traffic crashes. TransferBoost was further employed to build a crash risk model. Modeling using 2016 and 2017 data from the US26W freeway revealed a significant decrease in AUC and a gradual decrease in the model's sensitivity. However, the crash risk prediction performance of TransferBoost improved by 5.2% when modeling using 2017 data from US26W and I5N freeways. The results show that the model developed for one time period cannot be directly used to predict crash risk for another period on the same freeway. However, the model developed for one highway cannot be directly used to predict the crash risk of another highway either, maintaining some transferability at low false alarm rates. TransferBoost provides a fresh perspective on the transferability of the model. The findings of this study could facilitate more accurate proactive safety management and improvement countermeasure development.