Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
Opt Lett ; 49(13): 3725-3728, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38950252

RESUMEN

A material platform that excels in both optical second- and third-order nonlinearities at a telecom wavelength is theoretically and experimentally demonstrated. In this TiN-based coupled metallic quantum well structure, electronic subbands are engineered to support doubly resonant inter-subband transitions for an exceptionally high second-order nonlinearity and provide single-photon transitions for a remarkable third-order nonlinearity within the 1400-1600 nm bandwidth. The second-order susceptibility χ(2) reaches 2840 pm/V at 1440 nm, while the Kerr coefficient n2 arrives at 2.8 × 10-10 cm2/W at 1460 nm. The achievement of simultaneous strong second- and third-order nonlinearities in one material at a telecom wavelength creates opportunities for multi-functional advanced applications in the field of nonlinear optics.

2.
Nanoscale ; 16(30): 14490-14497, 2024 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-39022992

RESUMEN

The process of sorting light based on colors (photon energy) is a prerequisite in broadband optical systems, typically achieved in the form of guiding incoming signals through a sequence of spectral filters. The assembly of filters often leads to lengthy optical trains and consequently, large system footprints. In this work, we address this issue by proposing a flat color-sorting device comprising a diffraction grating and a dielectric Huygens' metasurface. Upon the incidence of a broadband beam, the grating disperses wavelengths to a continuous range of angles in accordance with the law of diffraction. The following metasurface with multiple paired Huygens' resonances corrects the dispersion and binds wavelengths to the corresponding waveband with a designated output angle. We demonstrate the sorting efficacy by designing a device with a color-sorting metasurface with two discrete dispersion-compensated outputs (10.8 ± 0.3 µm and 11.9 ± 0.3 µm), based on the proposed approach. The optimized metasurface possesses an overall transmittance exceeding 57% and reduces lateral dispersion by 90% at the output. The proposed color-sorting mechanism provides a solution that benefits the designing of metasurfaces for miniature multi-band systems.

3.
Cancer Cell Int ; 24(1): 208, 2024 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-38872157

RESUMEN

BACKGROUND: Lung adenocarcinoma (LUAD) patients have a dismal survival rate because of cancer metastasis and drug resistance. The study aims to identify the genes that concurrently modulate EMT, metastasis and EGFR-TKI resistance, and to investigate the underlying regulatory mechanisms. METHODS: Cox regression and Kaplan-Meier analyses were applied to identify prognostic oncogenes in LUAD. Gene set enrichment analysis (GSEA) was used to indicate the biological functions of the gene. Wound-healing and Transwell assays were used to detect migratory and invasive ability. EGFR-TKI sensitivity was evaluated by assessing the proliferation, clonogenic survival and metastatic capability of cancer cells with treatment with gefitinib. Methylated RNA immunoprecipitation (MeRIP) and RNA immunoprecipitation (RIP) analyses established the level of m6A modification present on the target gene and the protein's capability to interact with RNA, respectively. Single-sample gene set enrichment (ssGSEA) algorithm used to investigate levels of immune cell infiltration. RESULTS: Our study identified dual-specificity phosphatase 5 (DUSP5) as a novel and powerful predictor of adverse outcomes for LUAD by using public datasets. Functional enrichment analysis found that DUSP5 was positively enriched in EMT and transforming growth factor-beta (TGF-ß) signaling pathway, a prevailing pathway involved in the induction of EMT. As expected, DUSP5 knockdown suppressed EMT via inhibiting the canonical TGF-ß/Smad signaling pathway in in vitro experiments. Consistently, knockdown of DUSP5 was first found to inhibit migratory ability and invasiveness of LUAD cells in in vitro and prevent lung metastasis in in vivo. DUSP5 knockdown re-sensitized gefitinib-resistant LUAD cells to gefitinib, accompanying reversion of EMT progress. In LUAD tissue samples, we found 14 cytosine-phosphate-guanine (CpG) sites of DUSP5 that were negatively associated with DUSP5 gene expression. Importantly, 5'Azacytidine (AZA), an FDA-approved DNA methyltransferase inhibitor, restored DUSP5 expression. Moreover, RIP experiments confirmed that YTH N6-methyladenosine RNA binding protein 1 (YTHDF1), a m6A reader protein, could bind DUSP5 mRNA. YTHDF1 promoted DUSP5 expression and the malignant phenotype of LUAD cells. In addition, the DUSP5-derived genomic model revealed the two clusters with distinguishable immune features and tumor mutational burden (TMB). CONCLUSIONS: Briefly, our study discovered DUSP5 which was regulated by epigenetic modification, might be a potential therapeutic target, especially in LUAD patients with acquired EGFR-TKI resistance.

4.
Adv Mater ; 36(32): e2402751, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38816897

RESUMEN

The dual-focus vision observed in eagles' eyes is an intriguing phenomenon captivates scientists since a long time. Inspired by this natural occurrence, the authors' research introduces a novel bifocal meta-device incorporating a polarized camera capable of simultaneously capturing images for two different polarizations with slightly different focal distances. This innovative approach facilitates the concurrent acquisition of underfocused and overfocused images in a single snapshot, enabling the effective extraction of quantitative phase information from the object using the transport of intensity equation. Experimental demonstrations showcase the application of quantitative phase imaging to artificial objects and human embryonic kidney cells, particularly emphasizing the meta-device's relevance in dynamic scenarios such as laser-induced ablation in human embryonic kidney cells. Moreover, it provides a solution for the quantification during the dynamic process at the cellular level. Notably, the proposed eagle-eye inspired meta-device for phase imaging (EIMPI), due to its simplicity and compact nature, holds promise for significant applications in fields such as endoscopy and headsets, where a lightweight and compact setup is essential.

5.
Int J Biol Sci ; 18(7): 2962-2979, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35541909

RESUMEN

Tripartite motif-containing 44 (TRIM44) has recently been implicated in various pathological processes in numerous cancers, including lung adenocarcinoma (LUAD); however, its functional roles in chemoresistance are poorly understood. Herein, TRIM44 knockdown sensitized LUAD cells to cisplatin and enhanced cisplatin-induced apoptosis. Microarray analysis indicated that the "Role of BRCA1 in DNA damage" and the BRCA1 gene expression were positively regulated by TRIM44, which was further verified by immunofluorescence, qRT-PCR, and Western blotting. BRCA1 depletion effectively abolished TRIM44-modulated cisplatin resistance and regulation of homologous recombination (HR) repair. Interestingly, TRIM44 interacted with FLNA, an upstream regulator of BRCA1 as specified by STRING V 11.5, and facilitated its stability and deubiquitination. FLNA was also found to be required for the functions of TRIM44 in drug resistance. Using animal models, overexpression of TRIM44 was shown to confer resistance to cisplatin in a BRCA1- and FLNA-dependent manner. TRIM44 expression levels in tissues from cisplatin-resistant LUAD patients were significantly higher than those in tissues from cisplatin-sensitive LUAD patients. Collectively, our study results demonstrate that the TRIM44/FLNA/BRCA1 axis is involved in cisplatin chemoresistance, providing potential therapeutic targets for LUAD patients with cisplatin resistance.


Asunto(s)
Adenocarcinoma del Pulmón , Neoplasias Pulmonares , Adenocarcinoma del Pulmón/tratamiento farmacológico , Adenocarcinoma del Pulmón/genética , Animales , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Línea Celular Tumoral , Cisplatino/farmacología , Cisplatino/uso terapéutico , Reparación del ADN , Resistencia a Antineoplásicos , Filaminas/genética , Filaminas/metabolismo , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Proteínas de Motivos Tripartitos/genética , Proteínas de Motivos Tripartitos/metabolismo
6.
Clin Transl Med ; 12(4): e836, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35485206

RESUMEN

BACKGROUND: There is growing evidence that endocytosis plays a pivotal role in cancer metastasis. In this study, we first identified endocytic and metastasis-associated genes (EMGs) and then investigated the biological functions and mechanisms of EMGs. METHODS: Cancer stem cells (CSCs)-like characteristics were evaluated by tumour limiting dilution assays, three-dimensional (3D) spheroid cancer models. Microarray analysis was used to identify the pathways significantly regulated by mammalian Eps15 homology domain protein 1 (EHD1) knockdown. Mass spectrometry (MS) was performed to identify EHD1-interacting proteins. The function of EHD1 as a regulator of cluster of differentiation 44 (CD44) endocytic recycling and lysosomal degradation was determined by CD44 biotinylation and recycling assays. RESULTS: EHD1 was identified as a significant EMG. Knockdown of EHD1 suppressed CSCs-like characteristics, epithelial-mesenchymal transition (EMT), migration and invasion of lung adenocarcinoma (LUAD) cells by increasing Hippo kinase cascade activation. Conversely, EHD1 overexpression inhibited the Hippo pathway to promote cancer stemness and metastasis. Notably, utilising MS analysis, the CD44 protein was identified as a potential binding partner of EHD1. Furthermore, EHD1 enhanced CD44 recycling and stability. Indeed, silencing of CD44 or disruption of the EHD1/CD44 interaction enhanced Hippo pathway activity and reduced CSCs-like traits, EMT and metastasis. Interestingly, specificity protein 1 (SP1), a known downstream target gene of the Hippo-TEA-domain family members 1 (TEAD1) pathway, was found to directly bind to the EHD1 promoter region and induce its expression. Among clinical specimens, the EHD1 expression level in LUAD tissues of metastatic patients was higher than that of non-metastatic patients. CONCLUSIONS: Our findings emphasise that EHD1 might be a potent anti-metastatic target and present a novel regulatory mechanism by which the EHD1/CD44/Hippo/SP1 positive feedback circuit plays pivotal roles in coupling modules of CSCs-like properties and EMT in LUAD. Targeting this loop may serve as a remedy for patients with advanced metastatic LUAD.


Asunto(s)
Adenocarcinoma del Pulmón , Neoplasias Pulmonares , Adenocarcinoma del Pulmón/genética , Animales , Endocitosis/fisiología , Retroalimentación , Humanos , Receptores de Hialuranos/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Mamíferos/metabolismo , Factor de Transcripción Sp1 , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismo
7.
Cancer Lett ; 520: 12-25, 2021 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-34217785

RESUMEN

Mammalian Eps15 homology domain 1 (EHD1) participates in the development of non-small cell lung cancer (NSCLC). However, its role in mediating aerobic glycolysis remains unclear. Herein, microarray analysis revealed that EHD1 expression was significantly correlated with the glycolysis/gluconeogenesis pathway. Clinically, EHD1 expression was positively correlated with the maximum standard uptake value (SUVmax) in 18F-FDG PET/CT scans. Additionally, EHD1 knockdown inhibited aerobic glycolysis and proliferation in vitro and in vivo. Furthermore, Wnt/ß-catenin signaling was identified as a critical EHD1-regulated pathway. Co-IP, native gel electrophoresis, and immunoblotting showed that EHD1 contributed to 14-3-3 dimerization via 14-3-3ζ and subsequent activation of ß-catenin/c-Myc signaling. Analysis of the EHD1 regulatory region via ENCODE revealed the potential for c-Myc recruitment, leading to transcriptional activation of EHD1 and formation of an EHD1/14-3-3ζ/ß-catenin/c-Myc positive feedback circuit. Notably, blocking this circuit with a Wnt/ß-catenin inhibitor dramatically inhibited tumor growth in vivo. The positive correlations among EHD1, 14-3-3ζ, c-Myc, and LDHA were further confirmed in NSCLC tissues. Collectively, our study demonstrated that EHD1 activates a 14-3-3ζ/ß-catenin/c-Myc regulatory circuit that synergistically promotes aerobic glycolysis and may constitute a promising therapeutic target for NSCLC.


Asunto(s)
Proteínas 14-3-3/genética , Carcinoma de Pulmón de Células no Pequeñas/genética , L-Lactato Deshidrogenasa/genética , Proteínas de Transporte Vesicular/genética , beta Catenina/genética , Células A549 , Animales , Carcinoma de Pulmón de Células no Pequeñas/diagnóstico por imagen , Carcinoma de Pulmón de Células no Pequeñas/patología , Movimiento Celular/genética , Proliferación Celular/genética , Femenino , Regulación Neoplásica de la Expresión Génica/genética , Xenoinjertos , Humanos , Masculino , Ratones , Tomografía Computarizada por Tomografía de Emisión de Positrones , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas de Transporte Vesicular/ultraestructura , Efecto Warburg en Oncología , Vía de Señalización Wnt/genética
8.
Front Cell Dev Biol ; 9: 686975, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34124072

RESUMEN

Non-small-cell lung carcinoma (NSCLC) is considered to be a fatal disease and characterized by a poor prognosis. Long non-coding RNAs (lncRNAs) have been reported to act as biomarkers and therapeutic targets in solid tumors. However, the expression of lncRNAs and their clinical relevance in NSCLC remain undetermined. The gene expression data profiled in The Cancer Genome Atlas and Gene Expression Omnibus (GSE81089) were employed to screen differentially expressed lncRNAs in NSCLC. LINC02678 was found to be upregulated in NSCLC and exhibited hypomethylation of the promoter region in NSCLC tissues. LINC02678 (also called RP11-336A10.5) was associated with poorer overall survival and relapse-free survival in NSCLC patients. In vitro models of gain- and loss-of-function demonstrated that LINC02678 promotes NSCLC progression by promoting NSCLC cell proliferation and cell cycle progression, as well as inducing NSCLC cell migration, invasion and epithelial-mesenchymal transition. LINC02678 was primarily located in the nucleus and could bind with the enhancer of zeste homolog 2 (EZH2). Moreover, we found that LINC02678 knockdown impaired the occupancy capacity of EZH2 and trimethylation of lysine 27 on histone 3 (H3K27me3) at the promoter region of cyclin dependent kinase inhibitor 1B (CDKN1B) and E-cadherin, as confirmed by ChIP-qPCR. A mouse transplantation model further demonstrated that LINC02678 could promote the tumorigenic and metastatic capacities of NSCLC cells. We identified LINC02678 as a tumor promoter in NSCLC, which enhanced the growth and metastasis of NSCLC cells by binding with EZH2, indicating that LINC02678 may serve as a potential biomarker for cancer diagnosis and treatment.

9.
Nat Commun ; 12(1): 3111, 2021 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-34035272

RESUMEN

On-chip plasmonic circuitry offers a promising route to meet the ever-increasing requirement for device density and data bandwidth in information processing. As the key building block, electrically-driven nanoscale plasmonic sources such as nanoLEDs, nanolasers, and nanojunctions have attracted intense interest in recent years. Among them, surface plasmon (SP) sources based on inelastic electron tunneling (IET) have been demonstrated as an appealing candidate owing to the ultrafast quantum-mechanical tunneling response and great tunability. However, the major barrier to the demonstrated IET-based SP sources is their low SP excitation efficiency due to the fact that elastic tunneling of electrons is much more efficient than inelastic tunneling. Here, we remove this barrier by introducing resonant inelastic electron tunneling (RIET)-follow a recent theoretical proposal-at the visible/near-infrared (NIR) frequencies and demonstrate highly-efficient electrically-driven SP sources. In our system, RIET is supported by a TiN/Al2O3 metallic quantum well (MQW) heterostructure, while monocrystalline silver nanorods (AgNRs) were used for the SP generation (localized surface plasmons (LSPs)). In principle, this RIET approach can push the external quantum efficiency (EQE) close to unity, opening up a new era of SP sources for not only high-performance plasmonic circuitry, but also advanced optical sensing applications.

10.
J Oncol ; 2021: 2659550, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34987577

RESUMEN

BACKGROUND: Long noncoding RNAs (lncRNAs) could function as competitive endogenous RNAs (ceRNAs) to competitively adsorb microRNAs (miRNAs), thereby regulating the expression of their target protein-coding mRNAs. In this study, we aim to identify more effective diagnostic and prognostic markers for lung adenocarcinoma (LUAD). METHODS: We obtained differentially expressed lncRNAs (DElncRNAs), miRNAs (DEmiRNAs), and mRNAs (DEmRNAs) for LUAD by using The Cancer Genomes Atlas (TCGA) portal. Weighted gene coexpression network analysis (WGCNA) was performed to unveil core gene modules associated with LUAD. The Cox proportional hazards model was performed to determine the prognostic significance of DElncRNAs. The diagnostic and prognostic significance of DElncRNAs was further verified based on the receiver operating characteristic curve (ROC). Cytoscape was used to construct the ceRNA networks comprising the lncRNAs-miRNAs-mRNAs axis based on the correlation obtained from the miRcode, miRDB, and TargetScan. RESULTS: Compared with normal lung tissues, 2355 DElncRNAs, 820 DEmiRNAs, and 17289 DEmRNAs were identified in LUAD tissues. We generated 8 WGCNA core modules in the lncRNAs coexpression network, 5 modules in the miRNAs, and 12 modules in the mRNAs coexpression network, respectively. One lncRNA module (blue) consisting of 441 lncRNAs, two miRNA modules (blue and turquoise) containing 563 miRNAs, and one mRNA module (turquoise), which consisted of 15162 mRNAs, were mostly significantly related to LUAD status. Furthermore, 67 DEmRNAs were found to be tumor-associated as well as the target genes of the DElncRNAs-DEmiRNAs axis. Survival analyses showed that 6 lncRNAs (LINC01447, WWC2-AS2, OGFRP1, LINC00942, LINC01168, and AC005863.1) were significantly correlated with the prognosis of LUAD patients. Ultimately, the potential ceRNA networks including 6 DElncRNAs, 4 DEmiRNAs, and 22 DEmRNAs were constructed. CONCLUSION: Our study indicated that 6 DElncRNAs had the possibilities as diagnostic and prognostic biomarkers for LUAD. The lncRNA-mediated ceRNA networks might provide novel insights into the molecular mechanisms of LUAD progression.

11.
Front Cell Dev Biol ; 8: 550, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32719796

RESUMEN

Lung adenocarcinoma (LUAD) is a devastating disease with poor patient survival. Cancer immunotherapy has revolutionized the treatment of LUAD, but only a limited number of patients effectively respond to this treatment. Thus, the work to elucidate the LUAD immune heterogeneity could be crucial in developing new immunotherapeutic strategies with better efficacy. Non-negative matrix factorization-based deconvolution was performed to identify robust clusters of 489 LUAD patients in The Cancer Genome Atlas (TCGA) and verify their reproducibility and stability in an independent LUAD cohort of 439 patients from the Gene Expression Omnibus (GEO). We used the graph learning-based dimensionality reduction to visualize the distribution of individual patients. In this study, four reproducible immune subtypes, Clusters 1-4 (C1-C4) associated with distinct gene module signatures, clinicopathological features, molecular and cellular characteristics were identified and validated. The immune-cold subtype, C3, was associated with the Dead event, the most advanced T stage, N stage, TNM stage and the worst prognosis for LUAD patients. Moreover, C3 exhibited the lowest infiltrating levels of B cells, T cell receptor (TCR) repertoire diversity and the highest level of neoantigen and mutation rate among C1-C4. On the other hand, the immune-hot subtype (C4) exhibited the highest infiltration of six types of infiltrating immune cells as well as the greatest leukocyte fraction, TCR and B cell receptor (BCR) repertoire diversity. C1 and C2 subtypes showed diverse clinicopathological and immunological features. Finally, our investigations discovered a complex immune landscape with a scattered immune subtype profile. This work may help inform immunotherapeutic decision-making and design advanced immunotherapy strategies for the treatment of lung cancer.

12.
Thorac Cancer ; 10(11): 2124-2132, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31571378

RESUMEN

BACKGROUND: PH domain and leucine-rich repeat protein phosphatase 2 (PHLPP2) has been reported to be a potent tumor suppressor in many human cancers. However, PHLPP2 has not been fully researched as a putative clinical prognostic biomarker of lung cancer. METHODS: The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases including data on 1383 non-small cell lung cancer (NSCLC) patients were used to determine PHLPP2 expression. PHLPP2 expression was then examined by immunohistochemistry, and its clinical significance analyzed in 134 NSCLC patients, including 73 patients with adenocarcinoma and 81 with squamous cell carcinoma. RESULTS: We found PHLPP2 expression to be less pronounced in NSCLC tissue samples than that in nontumoral lung tissues according to data taken from TCGA and GEO datasets; this outcome was further validated by immunohistochemistry assay. The low PHLPP2 expression level was found to be associated with the presence of lymph node metastasis (P = 0.003). Importantly, PHLPP2 was found to be an independent indicator of prognosis for overall (hazard ratio [HR] = 0.520, 95% confidence interval [Cl] = 0.327-0.827; P = 0.006) and disease-free survival (HR = 0.489, 95% Cl = 0.308-0.775; P = 0.002) in patients with surgically-resected NSCLC by multivariate analysis. CONCLUSION: Taken together, our findings show that PHLPP2 is a robust clinical marker for NSCLC survival and could serve as a potential therapeutic target.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/patología , Regulación hacia Abajo , Neoplasias Pulmonares/patología , Fosfoproteínas Fosfatasas/genética , Fosfoproteínas Fosfatasas/metabolismo , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Metástasis Linfática , Masculino , Estadificación de Neoplasias , Pronóstico , Análisis de Supervivencia
13.
Molecules ; 24(14)2019 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-31295807

RESUMEN

The rate-limiting enzyme of the 2-methyl-d-erythritol-4-phosphate (MEP) terpenoid biosynthetic pathway, 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR), provides the perfect target for screening new antibacterial substances. In this study, we tested the DXR inhibitory effect of 35 plant essential oils (EOs), which have long been recognized for their antimicrobial properties. The results show that the EOs of Zanbthoxylum bungeanum (ZB), Schizonepetae tenuifoliae (ST), Thymus quinquecostatus (TQ), Origanum vulgare (OV), and Eugenia caryophyllata (EC) displayed weak to medium inhibitory activity against DXR, with IC50 values of 78 µg/mL, 65 µg/mL, 59 µg/mL, 48 µg/mL, and 37 µg/mL, respectively. GC-MS analyses of the above oils and further DXR inhibitory activity tests of their major components revealed that eugenol (EC) and carvacrol (TQ and OV) possess medium inhibition against the protein (68.3% and 55.6%, respectively, at a concentration of 20 µg/mL), whereas thymol (ST, TQ, and OV), carveol (ZB), and linalool (ZB, ST, and OV) only exhibited weak inhibition against DXR, at 20 µg/mL (23%-26%). The results add more details to the antimicrobial mechanisms of plant EOs, which could be very helpful in the direction of the reasonable use of EOs in the food industry and in the control of phytopathogenic microbials.


Asunto(s)
Isomerasas Aldosa-Cetosa/antagonistas & inhibidores , Antibacterianos/farmacología , Inhibidores Enzimáticos/farmacología , Escherichia coli/efectos de los fármacos , Escherichia coli/enzimología , Aceites Volátiles/farmacología , Aceites de Plantas/farmacología , Antibacterianos/química , Relación Dosis-Respuesta a Droga , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/química , Cromatografía de Gases y Espectrometría de Masas , Estructura Molecular , Aceites Volátiles/química , Fotometría/métodos , Aceites de Plantas/química
14.
Science ; 364(6436): 158-162, 2019 04 12.
Artículo en Inglés | MEDLINE | ID: mdl-30819930

RESUMEN

Graphene near charge neutrality is expected to behave like a quantum-critical, relativistic plasma-the "Dirac fluid"-in which massless electrons and holes collide at a rapid rate. We used on-chip terahertz spectroscopy to measure the frequency-dependent optical conductivity of clean, micrometer-scale graphene at electron temperatures between 77 and 300 kelvin. At charge neutrality, we observed the quantum-critical scattering rate characteristic of the Dirac fluid. At higher doping, we detected two distinct current-carrying modes with zero and nonzero total momenta, a manifestation of relativistic hydrodynamics. Our work reveals the quantum criticality and unusual dynamic excitations near charge neutrality in graphene.

15.
Fitoterapia ; 113: 80-4, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27439219

RESUMEN

1-Deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) is the first committed enzyme in the MEP terpenoid biosynthetic pathway and also a validated antimicrobial target. Green tea which is rich in polyphenolic components such as the catechins, possesses a plenty of pharmacological activities, in particular an antibacterial effect. To uncover the antibacterial mechanism of green tea and to seek new DXR inhibitors from natural sources, the DXR inhibitory activity of green tea and its main antimicrobial catechins were investigated in this study. The results show that the raw extract of green tea and its ethyl acetate fraction are able to suppress DXR activity explicitly. Further determination of the DXR inhibitory capacity of eight catechin compounds demonstrates that the most active compound is gallocatechin gallate that is able to inhibit around 50% activity of DXR at 25µM. Based on these data, the primary structure-activity relationship of the catechins against DXR is discussed. This study would be very helpful to elucidate the antimicrobial mechanism of green tea and the catechins and also would be very useful to direct the rational utilization of them as food additives.


Asunto(s)
Isomerasas Aldosa-Cetosa/antagonistas & inhibidores , Antibacterianos/química , Catequina/química , Té/química , Terpenos/química , Antibacterianos/aislamiento & purificación , Vías Biosintéticas/efectos de los fármacos , Catequina/análogos & derivados , Catequina/aislamiento & purificación , Extractos Vegetales/química , Relación Estructura-Actividad
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...