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The GATOR2-GATOR1 signaling axis is essential for amino-acid-dependent mTORC1 activation. However, the molecular function of the GATOR2 complex remains unknown. Here, we report that disruption of the Ring domains of Mios, WDR24, or WDR59 completely impedes amino-acid-mediated mTORC1 activation. Mechanistically, via interacting with Ring domains of WDR59 and WDR24, the Ring domain of Mios acts as a hub to maintain GATOR2 integrity, disruption of which leads to self-ubiquitination of WDR24. Physiologically, leucine stimulation dissociates Sestrin2 from the Ring domain of WDR24 and confers its availability to UBE2D3 and subsequent ubiquitination of NPRL2, contributing to GATOR2-mediated GATOR1 inactivation. As such, WDR24 ablation or Ring deletion prevents mTORC1 activation, leading to severe growth defects and embryonic lethality at E10.5 in mice. Hence, our findings demonstrate that Ring domains are essential for GATOR2 to transmit amino acid availability to mTORC1 and further reveal the essentiality of nutrient sensing during embryonic development.
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Complexos Multiproteicos , Serina-Treonina Quinases TOR , Animais , Camundongos , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Proteínas Nucleares/metabolismo , Transdução de SinaisRESUMO
With the overuse and misuse of antimicrobial drugs, antibacterial resistance is becoming a critical global health problem. New antibacterial agents are effective measures for overcoming the crisis of drug resistance. In this paper, a novel set of ciprofloxacin-indole/acetophenone hybrids was designed, synthesized, and structurally elucidated with the help of NMR and high-resolution mass spectrometry. The in vitro antibacterial activities of these hybrids against gram-positive and gram-negative pathogens, including four multidrug-resistant clinical isolates, were evaluated and compared with those of the parent drug ciprofloxacin (CIP). All the target compounds (MIC = 0.0625-32 µg/mL) exhibited excellent inhibitory activity against the strains tested. Among them, 3a (MIC = 0.25-8 µg/mL) showed comparable or slightly less potent activity than CIP. The most active hybrid, 8b (MIC = 0.0626-1 µg/mL), showed equal or higher activity than CIP. Moreover, compound 8b showed superior bactericidal capability to CIP, with undetectably low resistance frequencies. Furthermore, molecular docking studies conducted showed that 8b and CIP had a similar binding mode to DNA gyrase (Staphylocouccus aureus). Thus, hybrids 3a and 8b could act as a platform for further investigations.
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Antibacterianos , Ciprofloxacina , Ciprofloxacina/farmacologia , Simulação de Acoplamento Molecular , Antibacterianos/farmacologia , DNA Girase , Indóis/farmacologiaRESUMO
Capturing polarization information has long been an important topic in the field of detection. In this study, two polarization-dependent broadband absorbers based on a composite metamaterial structure were designed and numerically investigated. Unlike in conventional metamaterial absorbers, the bottom metallic film is functionalized to achieve a polarization response or broadband absorption. The simulation results show that the type I absorber exhibits TM polarization-dependent broadband absorption (absorptivity>80%) from 8.37 µm to 12.12 µm. In contrast, the type II absorber presents TE polarization-dependent broadband absorption (absorptivity>80%) from 8.23 µm to 11.93 µm. These devices are extremely sensitive to the change of polarization angle. The absorptivity changes monotonically with an increase of the polarization angle, but it is insensitive to oblique incidence. This design paves the way for realizing broadband polarization-dependent absorption via a simple configuration. It has bright prospects in thermal detection applications and imaging fields.
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OBJECTIVES: To characterize a glycosyltransferase (UGT74AN3) from Catharanthus roseus and investigate its specificity toward cardiotonic steroids and phenolic compounds. RESULTS: UGT74AN3, a novel permissive GT from C. roseus, displayed average high conversion rate (> 90%) toward eight structurally different cardiotonic steroids. Among them, resibufogenin, digitoxigenin, and uzarigenin gave 100% yield. Based on LC-MS, 1H-NMR and 13C-NMR analysis, structure elucidation of eight glycosides was consistent with 3-O-ß-D-glucosides. We further confirmed UGT74AN3 was permissive enough to glycosylate curcumin, resveratrol, and phloretin. The cDNA sequence of UGT74AN3 contained an ORF of 1,425 nucleotides encoding 474 amino acids. UGT74AN3 performed the maximum catalytic activity at 40 °C, pH 8.0, and was divalent cation-independent. Km values of UGT74AN3 toward resibufogenin, digitoxigenin, and uzarigenin were 7.0 µM, 12.3 µM, and 17.4 µM, respectively. CONCLUSIONS: UGT74AN3, a glycosyltransferase from a noncardenolide-producing plant, displayed catalytic efficiency toward cardiotonic steroids and phenolic compounds, which would make it feasible for glycosylation of bioactive molecules.
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Antiarrítmicos/metabolismo , Glicosídeos Cardíacos/metabolismo , Catharanthus/enzimologia , Glicosiltransferases/metabolismo , Fenóis/metabolismo , Biotransformação , Catharanthus/genética , Cromatografia Líquida , Clonagem Molecular , Inibidores Enzimáticos , Estabilidade Enzimática , Glicosilação , Glicosiltransferases/genética , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Especificidade por Substrato , TemperaturaRESUMO
A deep learning network called "residual neural network" (ResNet) was used to decode Raman spectra-encoded suspension arrays (SAs). With narrow bandwidths and stable signals, Raman spectra have ideal encoding properties. The different Raman reporter molecules assembled micro-quartz pieces (MQPs) were grafted with various biomolecule probes, which enabled simultaneous detection of numerous target analytes in a single sample. Multiple types of mixed MQPs were measured by Raman spectroscopy and then decoded by ResNet to acquire the type information of analytes. The good classification performance of ResNet was verified by a t-distributed stochastic neighbor embedding (t-SNE) diagram. Compared with other machine learning models, these experiments showed that ResNet was obviously superior in terms of classification stability and training convergence to different datasets. This method simplified the decoding process and the classification accuracy reached 100%.
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It has been well demonstrated that hypoxic preconditioning (HPC) can attenuate hypoxia/reoxygenation (H/R)-induced oxidant stress and elicit delayed cardioprotection by upregulating the expression of multiple antioxidative enzymes such as heme oxygenase-1 (HO-1), manganese superoxide dismutase (MnSOD) and so on. However, the underlying mechanisms of HPC-induced upregulation of antioxidative enzymes are not fully understood. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an essential transcription factor that regulates expression of several antioxidant genes via binding to the antioxidant response element (ARE) and plays a crucial role in cellular defence against oxidative stress. Here, we wondered whether activation of the Nrf2-ARE pathway is responsible for the induction of antioxidative enzymes by HPC and contributes to the delayed cardioprotection of HPC. Cellular model of HPC from rat heart-derived H9c2 cells was induced 24 h prior to H/R. The results showed that HPC efficiently attenuated H/R-induced viability loss and lactate dehydrogenase leakage. In addition, HPC increased nuclear translocation and ARE binding of Nrf2 during the late phase, upregulated the expression of antioxidative enzymes (HO-1 and MnSOD), inhibited H/R-induced oxidant stress. However, when Nrf2 was specifically knocked down by siRNA, the induction of antioxidative enzymes by HPC was completely abolished and, as a result, the inhibitory effect of HPC on H/R-induced oxidant stress was reversed, and the delayed cardioprotection induced by HPC was also abolished. These results suggest that HPC upregulates antioxidative enzymes through activating the Nrf2-ARE pathway and confers delayed cardioprotection against H/R-induced oxidative stress.
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Antioxidantes/metabolismo , Cardiotônicos/metabolismo , Precondicionamento Isquêmico Miocárdico , Miócitos Cardíacos/enzimologia , Miócitos Cardíacos/patologia , Fator 2 Relacionado a NF-E2/metabolismo , Regulação para Cima , Animais , Elementos de Resposta Antioxidante/genética , Hipóxia Celular , Linhagem Celular , Núcleo Celular/metabolismo , Técnicas de Silenciamento de Genes , Ligação Proteica , Transporte Proteico , Ratos , Transdução de Sinais , Estresse FisiológicoRESUMO
BACKGROUND: Reversion from mild cognitive impairment (MCI) to normal cognition (NC) is not uncommon and indicates a better cognitive trajectory. This study aims to identify predictors of MCI reversion and develop a predicting model. METHOD: A total of 391 MCI subjects (mean age = 74.3 years, female = 61 %) who had baseline data of magnetic resonance imaging, clinical, and neuropsychological measurements were followed for two years. Multivariate logistic analyses were used to identify the predictors of MCI reversion after adjusting for age and sex. A stepwise backward logistic regression model was used to construct a predictive nomogram for MCI reversion. The nomogram was validated by internal bootstrapping and in an independent cohort. RESULT: In the training cohort, the 2-year reversion rate was 19.95 %. Predictors associated with reversion to NC were higher education level (p = 0.004), absence of APOE4 allele (p = 0.001), larger brain volume (p < 0.005), better neuropsychological measurements performance (p < 0.001), higher glomerular filtration rate (p = 0.035), and lower mean arterial pressure (p = 0.060). The nomogram incorporating five predictors (education, hippocampus volume, the Alzheimer's Disease Assessment Scale-Cognitive score, the Rey Auditory Verbal Learning Test-immediate score, and mean arterial pressure) achieved good C-indexes of 0.892 (95 % confidence interval [CI], 0.859-0.926) and 0.806 (95 % CI, 0.709-0.902) for the training and validation cohort. LIMITATION: Observational duration is relatively short; The predicting model warrant further validation in larger samples. CONCLUSION: This prediction model could facilitate risk stratification and early management for the MCI population.
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Doença de Alzheimer , Disfunção Cognitiva , Humanos , Feminino , Idoso , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/patologia , Cognição , Imageamento por Ressonância Magnética , Hipocampo/patologia , Testes Neuropsicológicos , Doença de Alzheimer/diagnóstico por imagem , Progressão da DoençaRESUMO
It has been well accepted that increased reactive oxygen species (ROS) and the subsequent oxidative stress is one of the major causes of ischemia/reperfusion (I/R) injury. DJ-1 protein, as a multifunctional intracellular protein, plays an important role in regulating cell survival and antioxidant stress. Here, we wondered whether DJ-1 overexpression attenuates simulated ischemia/reperfusion (sI/R)-induced oxidative stress. A rat cDNA encoding DJ-1 was inserted into a mammalian expression vector. After introduction of this construct into H9c2 myocytes, stable clones were obtained. Western blot analysis of the derived clones showed a 2.6-fold increase in DJ-1 protein expressing. Subsequently, the DJ-1 gene-transfected and control H9c2 cells were subjected to sI/R, and then cell viability, lactate dehydrogenase, malondialdehyde, intracellular ROS and antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) were measured appropriately. The results showed that stable overexpression of DJ-1 efficiently attenuated sI/R-induced viability loss and lactate dehydrogenase leakage. Additionally, stable overexpression of DJ-1 inhibited sI/R-induced the elevation of ROS and MDA contents followed by the increase of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) activities and expression. Our data indicate that overexpression of DJ-1 attenuates ROS generation, enhances the cellular antioxidant capacity and prevents sI/R-induced oxidative stress, revealing a novel mechanism of cardioprotection. Importantly, DJ-1 overexpression may be an important part of a protective strategy against ischemia/reperfusion injury.
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Hipóxia/genética , Hipóxia/metabolismo , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Estresse Oxidativo/genética , Animais , Células Cultivadas , Peroxirredoxinas , Proteína Desglicase DJ-1 , RatosRESUMO
The mechanistic target of rapamycin complex 1 (mTORC1) controls cell growth in response to amino acid and glucose levels. However, how mTORC1 senses glucose availability to regulate various downstream signalling pathways remains largely elusive. Here we report that AMP-activated protein kinase (AMPK)-mediated phosphorylation of WDR24, a core component of the GATOR2 complex, has a role in the glucose-sensing capability of mTORC1. Mechanistically, glucose deprivation activates AMPK, which directly phosphorylates WDR24 on S155, subsequently disrupting the integrity of the GATOR2 complex to suppress mTORC1 activation. Phosphomimetic Wdr24S155D knock-in mice exhibit early embryonic lethality and reduced mTORC1 activity. On the other hand, compared to wild-type littermates, phospho-deficient Wdr24S155A knock-in mice are more resistant to fasting and display elevated mTORC1 activity. Our findings reveal that AMPK-mediated phosphorylation of WDR24 modulates glucose-induced mTORC1 activation, thereby providing a rationale for targeting AMPK-WDR24 signalling to fine-tune mTORC1 activation as a potential therapeutic means to combat human diseases with aberrant activation of mTORC1 signalling including cancer.
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Proteínas Quinases Ativadas por AMP , Alvo Mecanístico do Complexo 1 de Rapamicina , Complexos Multiproteicos , Serina-Treonina Quinases TOR , Animais , Humanos , Camundongos , Proteínas Quinases Ativadas por AMP/metabolismo , Glucose , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Complexos Multiproteicos/metabolismo , Fosforilação , Serina-Treonina Quinases TOR/metabolismoRESUMO
This study aimed to construct an effective nomogram based on the clinical and oxidative stress-related characteristics to predict the prognosis of stage I lung adenocarcinoma (LUAD). A retrospective study was performed on 955 eligible patients with stage I LUAD after surgery at our hospital. The relationship between systematic-oxidative-stress biomarkers and the prognosis was analyzed. The systematic oxidative stress score (SOS) was established based on three biochemical indicators, including serum creatinine (CRE), lactate dehydrogenase (LDH), and uric acid (UA). SOS was an independent prognostic factor for stage I LUADs, and the nomogram based on SOS and clinical characteristics could accurately predict the prognosis of these patients. The nomogram had a high concordance index (C-index) (0.684, 95% CI, 0.656-0.712), and the calibration curves for recurrence-free survival (RFS) probabilities showed a strong agreement between the nomogram prediction and actual observation. Additionally, the patients were divided into two groups according to the cut-off value of risk points based on the nomogram, and a significant difference in RFS was observed between the high-risk and low-risk groups (p < 0.0001). SOS is an independent prognostic indicator for stage I LUAD. These things considered, the constructed nomogram based on SOS could accurately predict the survival of those patients.
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Cyclic GMP-AMP synthase (cGAS) is the major sensor for cytosolic DNA and activates type I interferon signaling and plays an essential role in antitumor immunity. However, it remains unclear whether the cGAS-mediated antitumor activity is affected by nutrient status. Here, our study reports that methionine deprivation enhances cGAS activity by blocking its methylation, which is catalyzed by methyltransferase SUV39H1. We further show that methylation enhances the chromatin sequestration of cGAS in a UHRF1-dependent manner. Blocking cGAS methylation enhances cGAS-mediated antitumor immunity and suppresses colorectal tumorigenesis. Clinically, cGAS methylation in human cancers correlates with poor prognosis. Thus, our results indicate that nutrient stress promotes cGAS activation via reversible methylation, and suggest a potential therapeutic strategy for targeting cGAS methylation in cancer treatment.
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Cromatina , Metionina , Humanos , Cromatina/genética , Metionina/genética , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , DNA , Imunidade Inata , Desmetilação , Proteínas Estimuladoras de Ligação a CCAAT/genética , Ubiquitina-Proteína Ligases/genéticaRESUMO
Myocardial preconditioning is a powerful phenomenon that can attenuate ischemia/reperfusion-induced oxidant stress and elicit delayed cardioprotection. Its mechanisms involve activation of intracellular signaling pathways and up-regulation of the protective antioxidant proteins. DJ-1 protein, as a multifunctional intracellular protein, plays an important role in attenuating oxidant stress and promoting cell survival. In the present study, we investigated whether DJ-1 is up-regulated during the late phase of hypoxic preconditioning (HP) and the up-regulation of DJ-1 is mediated by extracellular-regulated kinase 1/2 (ERK1/2) signaling pathway. Rat heart-derived H9c2 cells were exposed to HP. Twenty-four hours later cells were subjected to hypoxia/reoxygenation (H/R) and then cell viability, lactate dehydrogenase (LDH), intracellular reactive oxygen species (ROS), ERK1/2 phosphorylation, and DJ-1 protein were measured appropriately. The results showed that HP efficiently attenuated H/R-induced viability loss and LDH leakage. In addition, HP promoted ERK1/2 activation, up-regulated DJ-1 protein expression, inhibited H/R induced the elevation of ROS. However, when ERK1/2 phosphorylation was specifically inhibited by U0126, the increase in DJ-1 expression occurring during HP was almost completely abolished and, as a result, the delayed cardioprotection induced by HP was abolished, and the inhibitory effect of HP on H/R-induced oxidant stress was also reversed. Furthermore, knocking down DJ-1 by siRNA attenuated the delayed cardioprotection induced by HP. Our data indicate that HP can up-regulate DJ-1 protein expression through the ERK1/2-dependent signaling pathway. Importantly, DJ-1 might be involved in the delayed cardioprotective effect of HP against H/R injury.
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Hipóxia/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Miocárdio/enzimologia , Miocárdio/patologia , Regulação para Cima , Animais , Butadienos/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Técnicas de Silenciamento de Genes , L-Lactato Desidrogenase/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , NF-kappa B/metabolismo , Nitrilas/farmacologia , Oxigênio , Proteína Desglicase DJ-1 , RNA Interferente Pequeno/metabolismo , Ratos , Espécies Reativas de Oxigênio/metabolismo , Fatores de Tempo , Regulação para Cima/efeitos dos fármacosRESUMO
Parkinson's disease (PD) is a common disease which occurs in aged people with chronic, progressive degenerative character of the central nervous system. Until now there is no effective treatment method in PD patients before they show obvious symptoms for prevention and early diagnosis. In order to find out early disease specific biomarkers, two-dimensional liquid chromatography-tandem mass spectrometry coupled with isobaric tags for relative and absolute quantification (iTRAQ) labeling was employed to quantitatively identify the differentially expressed proteins among the different disease progress types of PD. 26 proteins were differentially expressed in a total of 258 identified proteins by proteomic techniques. The expression level of eight proteins which included sero-transferrin and clusterin increased. The expression level of eighteen proteins which include complement component 4B, apolipoprotein A-I, α-2-antiplasmin and coagulation factor V decreased. Those proteins may be associated with oxidative stress, mitochondrial dysfunction, abnormal protein aggregation and inflammation. In this study, the expression level of apolipoprotein A-I decreased, particularly in the early stage of PD patients. This protein regulated not only the lipid metabolism in the central nervous system, but also influenced the deposition process of proteins which are involved in neural degenerative diseases, such as the pathogenesis of PD.
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Biomarcadores/análise , Biomarcadores/sangue , Proteínas Sanguíneas/análise , Cromatografia Líquida , Doença de Parkinson/sangue , Proteoma/análise , Espectrometria de Massas em Tandem , Western Blotting , Humanos , Doença de Parkinson/diagnóstico , Fragmentos de Peptídeos/análise , ProteômicaRESUMO
Background: Telomere length, which is related to chronic diseases and premature mortality, is influenced by dietary factors. Zinc is known as a dietary antioxidant micronutrient, however, its impact on telomere length remains unclear. Objective: We aimed to examine the potential effect of dietary zinc intake on telomere length among middle-aged and older individuals in the US. Materials and methods: Our study included 3,793 US participants aged 45 years and older from the 1999 to 2002 National Health and Nutrition Examination Survey (NHANES). 24-h dietary recall interviews were employed to evaluate zinc consumption. Leukocyte telomere length was assessed by real-time quantitative polymerase chain reaction (qPCR). We adopted generalized linear models to investigate the effect of dietary zinc intake on telomere length, and subgroup analyses were further applied. We further evaluated the dose-response relationship using restricted cubic spline analysis. Results: Among the 3,793 participants, the average telomere length was 0.926 ± 0.205 (T/S ratio) or 5509.5 ± 494.9 (bp). After adjusting for major confounders, every 5 mg increment in dietary zinc consumption was related to 0.64% (95% CI: 0.17%, 1.10%) longer telomere length. In the subgroup analyses, significant relationships were found in females (Percentage change: 1.11%; 95% CI: 0.48%, 1.75%), obese (Percentage change: 0.88%; 95% CI: 0.26%, 1.50%), and low energy intake individuals (Percentage change: 0.99%; 95% CI: 0.51%, 1.46%). Additionally, we revealed a positive linear relationship between dietary zinc intake and telomere length (P for non-linearity = 0.636). Conclusion: Our study revealed that elevated dietary zinc intake was significantly related to longer telomere length among adults aged 45 years and older in the US. And the association was more pronounced in females, obese, and low energy intake individuals.
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Objective: The prognostic effect of delayed treatment on stage IA1 non-small cell lung cancer (NSCLC) patients is still unclear. This study aimed to explore the association between the waiting time before treatment and the prognosis in stage IA1 NSCLC patients. Methods: Eligible patients diagnosed with pathological stage IA1 NSCLC were included in this study. The clinical endpoints were overall survival (OS) and cancer-specific survival (CSS). The Kaplan-Meier method, the Log-rank test, univariable, and multivariable Cox regression analyses were used in this study. Propensity score matching was used to reduce the bias of data distribution. Results: There were eligible 957 patients in the study. The length of waiting time before treatment stratified the survival in patients [<3 months vs. ≥3-months, unadjusted hazard ratio (HR) = 0.481, P = 0.007; <2 months vs. ≥2-months, unadjusted HR = 0.564, P = 0.006; <1 month vs. ≥1-month, unadjusted HR = 0.537, P = 0.001]. The 5-year CSS rates were 95.0% and 77.0% in patients of waiting time within 3 months and over 3 months, respectively. After adjusting for other confounders, the waiting time was identified as an independent prognostic factor. Conclusions: A long waiting time before treatment may decrease the survival of stage IA1 NSCLC patients. We propose that the waiting time for those patients preferably is less than one month and should not exceed two months.
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Carcinoma-associated fibroblasts (CAFs), one of the most important components of a tumor microenvironment (TME), play a significant role in the complex tumorigenesis process. Herein, the evolution of CAFs in TME is elaborately investigated by surface-enhanced Raman spectroscopy (SERS), a molecular fingerprint technique. Two-dimensional (2D) nanocomposites consisting of gold nanoparticles and a supramolecular "PCsheet" self-assembled between 2D nanosheets and oxidized phosphatidylcholine (PC) are fabricated as SERS-active probes to specifically recognize the CD36 receptor on the cytomembrane of the fibroblasts, a reliable landmark of CAF development. The 2D SERS substrates can also illuminate the fingerprint information around the CD36 protein with high detection sensitivity, which helps elucidate the biochemical component transition in the protein mini-domain during carcinoma progression. Visualized data are then supplied by label-free SERS imaging to exploit the distribution of biomolecules on the plasma membrane. In addition, the repressed expression of CD36 in TME is detected in lung metastasis tumor-bearing mice. This study based on the 2D SERS technique opens up an alternative avenue for unveiling carcinoma-associated molecular events.
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Fibroblastos/metabolismo , Ouro , Neoplasias Pulmonares , Nanopartículas Metálicas , Nanocompostos , Microambiente Tumoral , Animais , Fibroblastos/patologia , Ouro/química , Ouro/farmacologia , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Nanopartículas Metálicas/química , Nanopartículas Metálicas/uso terapêutico , Camundongos , Células NIH 3T3 , Nanocompostos/química , Nanocompostos/uso terapêutico , Metástase NeoplásicaRESUMO
By means of a simple and photo-induced method, four colors of molybdenum oxide quantum dots (MoOx QDs) have been synthesized, using Mo(CO)6 as the structural guiding agent and molybdenum source. The as-prepared MoOx QDs display diverse optical properties due to the different configurations of oxygen vacancies in various nanostructures. Among them, crystalline molybdenum dioxide (MoO2) with a deep blue color shows the most intense localized surface plasmon resonance effect in the near-infrared (NIR) region. The strong NIR absorption endows MoO2 QDs with a high photothermal conversion efficiency of 66.3%, enabling broad prospects as a photo-responsive nanoagent for photothermal therapy of cancer. Moreover, MoO2 QDs can also serve as a novel semiconductor substrate for ultrasensitive surface-enhanced Raman scattering (SERS) analysis of aromatic molecules, amino acids and antibiotics, with SERS performance comparable to that of noble metal-based substrates. The therapeutic applications of MoO2 QDs open up a new avenue for tumor nanomedicine.
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Molibdênio/farmacologia , Óxidos/farmacologia , Terapia Fototérmica , Pontos Quânticos/química , Apoptose/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Hep G2 , Humanos , Teste de Materiais , Molibdênio/química , Nanoestruturas/química , Óxidos/síntese química , Óxidos/química , Tamanho da Partícula , Processos Fotoquímicos , Análise Espectral Raman , Propriedades de Superfície , Temperatura , Células Tumorais CultivadasRESUMO
PURPOSE: This study aims to explore consumers' implicit motivations for purchasing luxury brands based on the functional theories of attitudes by using event-related potentials (ERPs). METHODS: Brand authenticity and logo prominence were used to modulate the social-adjustive function and value-expressive function, respectively. Twenty right-handed healthy female undergraduates and graduates participated in an experiment that has a 2 brand authenticity (genuine/counterfeit) × 2 brand prominence (prominent logo/no logo) design. In the experiment, participators browsed different luxury handbags with different brand authenticity and logo prominence, and then reported their purchase intentions on a five-point scale. Meanwhile, EEGs were recorded from the subjects throughout the experiment. In the analysis process, three ERP components, which can, respectively, reflect the cognitive conflict (N200), emotional conflict (N400) and motivational emotional arousal (LPP) during the evaluation of marketing-related stimuli, were mainly focused. RESULTS: For counterfeit brands, the no logo condition elicited significant larger N200 amplitude, marginally significant larger N400 amplitude and significant smaller LPP amplitude than the prominent logo condition. However, for genuine brands, this modulation effect of logo prominence cannot be found. These results imply that consumers' implicit social motivations for purchasing luxury brands come from the satisfaction of at least one social goal. When one goal cannot be satisfied, consumers will more expect the satisfaction of another one. If this expectation is violated, it seems to be unexpected and unacceptable. Thus, greater anticipation conflict (N200) and emotion conflict (N400) will be induced, and the purchase motivation (LPP) cannot be aroused. CONCLUSION: Consumers' preferences for luxury brands are based on the satisfaction of their social goals. These social goals always coexist and perform as compensation with each other. The dissatisfaction of one social goal would promote their expectation of the satisfaction of another social goal.
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Nowadays, the international community is becoming increasingly concerned about the sustainable utilization of natural resources. In order to protect the environment and reward sustainable practices, eco-labeling that signifies the environmental friendliness of the labeled food is already widely promoted in many regions around the world. Thus, it is of great importance for researchers to study consumers' attitudes toward eco-labeled food as food is supposed to satisfy consumers' needs. This study employed the event-related potentials (ERPs) approach to investigate consumers' attitudes toward eco-labeled food by comparing their neural processing of visual stimuli depicting eco-labeled and non-labeled food. Our results showed that behaviorally, participants preferred to buy eco-labeled food rather than non-labeled one. At the neural level, we observed markedly smaller P2 and N2 amplitudes when pictures of eco-labeled food were presented. Furthermore, we also found that amplitudes of P2 were negatively correlated with participants' purchase intention. Therefore, our current findings suggest that, while the environmental-friendly eco-labeling was not to one's own interests, it might still be evocative, which induce consumers' positive emotion, bring less cognitive conflict to the purchase decision-making and then result in a greater purchasing intention. This effect might be the result of the delivered value of social desirability.
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As herding is a typical characteristic of human behavior, many researchers have found the existence of herding behavior in online peer-to-peer lending through empirical surveys. However, the underlying neural basis of this phenomenon is still unclear. In the current study, we studied the neural activities of herding at decision-making stage and feedback stage using event-related potentials (ERPs). Our results showed that at decision-making stage, larger error related negativity (ERN) amplitude was induced under low-proportion conditions than that of high-proportion conditions. Meanwhile, during feedback stage, negative feedback elicited larger feedback related negativity (FRN) amplitude than that of positive feedback under low-proportion conditions, however, there was no significant FRN difference under high-proportion conditions. The current study suggests that herding behavior in online peer-to-peer lending is related to individual's risk perception and is possible to avoid negative emotions brought by failed investments.