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m6A modification is the most abundant mRNA modifications and plays an integral role in various biological processes in eukaryotes. However, the role of m6A regulators in rheumatoid arthritis remains unknown. To determine the expression of m6A RNA methylation regulators in rheumatoid arthritis and their possible functional and prognostic value. In this study, we performed differential analysis in the comprehensive gene expression database GSE93272 dataset between non-rheumatoid arthritis patients and rheumatoid arthritis patients to obtain 15 important m6A regulators. A random forest model and lasso regression were used to screen the five most important m6A regulators to predict the risk of developing rheumatoid arthritis. After further validation using in vitro qPCR experiments, a nomogram model was developed based on the four most important m6A regulators (ELAVL1, WTAP, YTHDF1, and ALKBH5). Immuno-infiltration analysis and consensus clustering analysis were then performed. An analysis of the decision curve showed that the nomogram model could be beneficial to patients. According to selected important m6A regulators, patients with rheumatoid arthritis were classified into two m6A models (ClusterA and ClusterB) via consensus approach. Activated B cells, CD56dim natural killer cells, immature B cells, monocytes, natural killer T cells, and T lymphocytes were associated with ClusterA in immune infiltration analysis. Importantly, immune infiltration in patients with high ELAVL1 expression was strikingly similar to ClusterA. m6A regulators play a non-negligible role in the development of rheumatoid arthritis. A study of m6A patterns may provide future therapeutic options for rheumatoid arthritis.
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Three aggregation-induced emission active fluorescent compounds, TPA-Pyr-Octane, TPA-Pyr-Br, and TPA-Pyr-Thiourea (TPA = triphenylamine pyridinium), are synthesized; their tiny differences in chemical structures result in a huge difference in cell-imaging applications. Especially, incorporating thiourea into fluorescent probes is found as a reliable strategy for mitochondrion-targeted imaging and superoxide anion tracking in living cells, which is possibly due to the presence of hydrogen bonding between thiourea and mitochondrion proteins. This finding is very useful for the design of biosensors and delivery carriers in disease treatment.
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Corantes Fluorescentes/química , Mitocôndrias/química , Imagem Óptica , Superóxidos/análise , Tioureia/química , Ânions/análise , Corantes Fluorescentes/síntese química , Células HeLa , Humanos , Ligação de Hidrogênio , Mitocôndrias/metabolismo , Proteínas Mitocondriais/química , Proteínas Mitocondriais/metabolismo , Superóxidos/metabolismoRESUMO
Aggregation-induced emission (AIE) and antenna effect (AE) are two important luminescence behaviors. Connecting them into polymers is a promising but challenging work, which can supply opportunities for luminescence materials with extensive applications. In this work, AIE-active Eu3+-coordinated polymers (Poly-Eu-1, -2, -3, and -4) have been synthesized, and the efficient AE was verified. This finding presents a facile approach to obtain the Ln3+-based solid luminescence materials due to the synergistic effect from AIE and AE. Also, benefiting from the film-processing ability and water solubility, Poly-Eu-1, -2, -3, and -4 could be employed with different application purposes. In the solution phase, they can be used as sensitive optical probes to detect trace amounts of H2O and D2O, and the limit of detection (LOD) of Poly-Eu-2 toward D2O in H2O is determined to be 7.8 ppm. This discovery is a novel strategy for the construction of D2O optical sensors with a totally intervention-free style.
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Fluorescent probes are powerful tools for investigating reactive oxygen species (ROS) in living organisms. The overproduced "primary" ROS of superoxide anions (O2Ë-) cause a chain of oxidative damage. In order to monitor O2Ë- level fluctuations in living cells, we synthesized two reaction-type probes of TPA-DHP-1,2,3 and TPA-PPA-1,2,3, which were composed of an electron-rich triphenylamine (TPA) and the very active functional groups of dihydropyridine (DHP) and pyridinium (PPA). Intriguingly, DHP and PPA were able to carry out easy proton abstractions and nucleophilic reactions in the presence of O2Ë-, resulting in the corresponding products with sharp wavelength shifts, and elevated fluorescence intensities. Therefore, undesirable background fluorescence interference can be reduced during the monitoring and imaging process. Meanwhile, the developed dual-channel monitoring strategy not only provides observations of the O2Ë- level fluctuations, but could also be employed to image the dynamic accumulation process of probes in the different cell organelles. Therefore, the design could provide a simple, accurate and universal platform for biological applications in future research work.
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Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Imagem Óptica/métodos , Superóxidos/metabolismo , Arsenicais/química , Células HeLa , Humanos , Modelos Moleculares , Conformação Molecular , Fenômenos Ópticos , Fatores de TempoRESUMO
We have developed an innovative pathological biopsy strategy by expanding the differences of ROS levels among cancer cells, inflammatory cells and normal cells using cross-linked lipoic acid vesicles loaded with vitamin C (VC@cLAVs), combined with chemiluminescence imaging technology. By analyzing the different trends of intracellular chemiluminescence intensity, the three types of cells were quickly and accurately differentiated from diseased tissues, thus holding clinical tumor diagnostic potential.
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Ácido Ascórbico , Espécies Reativas de Oxigênio , Ácido Tióctico , Humanos , Espécies Reativas de Oxigênio/metabolismo , Espécies Reativas de Oxigênio/análise , Ácido Tióctico/química , Ácido Ascórbico/farmacologia , Ácido Ascórbico/química , Biópsia , Neoplasias/patologia , Neoplasias/diagnóstico por imagem , Medições LuminescentesRESUMO
Improving the efficiency of platinum group metals (Pt, Pd, Rh, etc.) in catalytic oxidation reactions remains an urgent topic. The conflict between the low-temperature activity and high-temperature stability of noble metals can hardly reach a consensus. For instance, Pt cluster catalysts supported on CeO2 with high low-temperature activity will suffer from deactivation due to the redispersion under high-temperature lean-burn reaction conditions. Herein, two Pt1/CeO2 prepared by the incipient wetness impregnation method using different Pt precursors possessed varied Pt-O and Pt-O-Ce coordination numbers (CNs). They showed various priorities in CO oxidation versus NH3 selective catalytic oxidation, materials with higher CNPt-O-Ce selectively catalyzing NH3 oxidation to N2 more superior, conversely materials with lower CNPt-O-Ce performing better in CO oxidation. After activation by H2 reduction, both formed massive Pt clusters on the CeO2 surface but showed drastically distinct stability in lean-burn CO oxidation reactions. By summarizing the experimental results of high-angle annular dark-field scanning transmission electron microscopy, X-ray absorption spectroscopy, Raman spectroscopy, in situ diffuse reflectance infrared Fourier transform spectroscopy, etc., it is beyond doubt that the difference in the initial states of Pt1 due to distinct precursors indeed determine the redispersion behavior of the reduced Pt clusters on CeO2. Materials with lower CNPt-O-Ce and higher CNPt-O are more likely to form robust Pt clusters, as they are not conducive to Pt anchoring, thus restricting the reversible structural evolution occurring under lean-burn CO oxidation and reductive conditions. This approach serves as a guide for the convenient and efficient construction and exploration of robust Pt cluster catalysts.
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BACKGROUND: Quadricuspid aortic valve (QAV) is a rare congenital heart disease with a limited body of literature. This retrospective cohort study investigates QAV morphology, function, and clinical outcomes. METHODS: Echocardiography was used to assess valvular function. Morphological characteristics such as phenotypes, raphe, regurgitant orifice area (ROA), and aortic dilation (diameter >40 âmm) were assessed by cardiac CT. Patients were followed up for the combined event of all-cause death and aortic valve replacement (AVR). RESULTS: Ninety QAV patients (screened from 322385 CT scans) were included (mean age 55.2 â± â13.6 years, 61.1 â% male). Isolated significant aortic regurgitation (AR) was present in 75.6 â% of patients. The cohort was dominated by type I (four equal leaflets, 37.8 â%) and type II (3 larger and 1 smaller leaflets, 42.2 â%) QAV. Fused raphe was present in 26.7 â% of patients. ROACT was correlated with AR severity and aortic dilation (41.1 â%, n â= â37). Among patients without AVR at baseline (n â= â60), one died and 17 underwent AVR during a median follow-up of 35.0 months (IQR:17.3-62.8). ROACT was associated with an increasing risk of combined event (as a categorical variable with a cut-off of 21.4 âmm2, HR â= â4.25, 95%CI 1.49-12.17, p â= â0.007; as a continuous variable (per mm2 increment), HR â= â1.04, 95%CI 1.01-1.07, p â= â0.003). Additionally, ROACT had incremental prognostic value when added to the AR severity model (area under the receiver-operating characteristic curve increased from 86.8 to 88.4, p â= â0.004). CONCLUSION: QAV is characterized by variable anatomy, progressive AR, concomitant cusp fusion and aortic enlargement. ROACT may be a potential ancillary prognostic marker in patients with QAV.
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Doenças da Aorta , Insuficiência da Valva Aórtica , Válvula Aórtica Quadricúspide , Humanos , Masculino , Adulto , Pessoa de Meia-Idade , Idoso , Feminino , Estudos Retrospectivos , Valor Preditivo dos Testes , Valva Aórtica/diagnóstico por imagem , Valva Aórtica/cirurgia , Valva Aórtica/anormalidades , Insuficiência da Valva Aórtica/diagnóstico por imagem , Insuficiência da Valva Aórtica/etiologia , Insuficiência da Valva Aórtica/cirurgia , HemodinâmicaRESUMO
Evolution of the synthetic strategy that culminated in the first asymmetric total synthesis of the Aspidosperma alkaloid limaspermidine is described. The successful enantioselective route to (-)-limaspermidine proceeds in 10 steps and with the isolation of only six intermediates using a Pd-catalyzed enantioselective decarboxylative allylation we have recently developed. This first enantioselective synthesis of (-)-limaspermidine establishes unambiguously its absolute configuration and allows the first asymmetric formal total synthesis of the Aspidoalbine alkaloid (-)-1-acetylaspidoalbidine.
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Alcaloides Indólicos/síntese química , Alcaloides Indólicos/química , Estrutura Molecular , EstereoisomerismoRESUMO
BACKGROUND: A characteristic feature of communicating aortic dissections (CD) is the dissection flap between the true and false lumen. However, in intramural hematomas (IMH) a flap is not visible. We aimed to determine if cross-sectional HU variability allow reliable identification of aortic dissections including IMH. METHODS: We included 362 patients presenting with acute chest pain (CP) or respiratory distress (RD) and underwent contrast-enhanced CTA with or without ECG-gating. In the derivation group we included 72 CP patients with and 74 without AAS. In the validation group we included 108 CP or RD patients with and 108 without AAS. The adventitial border of the aorta was visually identified and measurements were performed at 6 locations along the ascending and descending aorta. At each cross-section 5 circular ROI measurements of HU were made and the maximum HU difference calculated. RESULTS: In the derivation and validation group the maximum difference in HUs at any one location was significantly higher for AAS subjects than controls (validation group: median = 128.5 vs. 34.0, p-value Wilcoxon two-sample test <0.001). In the validation group, the estimated AUC was 0.939 with 95% CIs of [0.906, 0.972], indicating that the maximum difference in HUs is a strong predictor of AAS (p < 0.001). CONCLUSION: Our data provide evidence that cross-sectional variability of Hounsfield Unit reliably identifies aortic dissection including IMH in dedicated ECG-gated aorta scans but also non-gated chest CTs with limited aortic contrast enhancement. These results suggest that this approach could be feasible for an automated algorithm for identification of AAS.
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Síndrome Aórtica Aguda , Doenças da Aorta , Dissecção Aórtica , Humanos , Estudos Transversais , Dissecção Aórtica/diagnóstico por imagem , Aorta , Hematoma , Doenças da Aorta/diagnóstico por imagem , Estudos RetrospectivosRESUMO
A new class of chiral primary amine catalysts bearing multiple hydrogen-bonding donors have been designed and synthesized. The newly developed bifunctional organocatalysts efficiently catalyzed not only enantioselective conjugate addition of aromatic ketones to nitroolefins in good yields (up to 87%) with excellent enantioselectivities (97â99% ee) but also enantioselective conjugate addition of acetone to nitroolefins in excellent yields (90-96%) with high enantioselectivities (up to 97% ee).
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Acetona/química , Alcenos/química , Aminas/química , Cetonas/química , Catálise , Ligação de Hidrogênio , Estrutura Molecular , EstereoisomerismoRESUMO
Potential health benefits of tea has attracted significant scientific and public attention worldwide. Tea polyphenols are considered as natural promising complementary therapeutical agents for neurodegenerative diseases. However, the anti-neurodegeneration or anti-aging activities of oolong tea polyphenols have not been investigated. The current study aims to document beneficial effects of oolong tea polyphenols [dimers of epigallocatechin gallate (EGCG), oolonghomobisflavan A (OFA), and oolonghomobisflavan B (OFB)] with neuroprotective and neuritogenesis properties in cultured neuronal (Neuro-2a and HT22) cells and Caenorhabditis elegans models. In vitro, we found that the compounds (EGCG, OFA, and OFB) protect against glutamate-induced neurotoxicity via scavenging radical activity, suppression intracellular ROS and up-regulation of antioxidant enzymes. Moreover, the compounds induce neurite outgrowth via up-regulate Ten-4 gene expression. Interestingly, OFA and OFB exert stronger neuroprotective and neurite outgrowth properties than EGCG known as an excellent antioxidant agent in tea. In vivo, we found that the compounds protect against C. elegans Aß-induced paralysis, chemotaxis deficiency and α-synuclein aggregation. Moreover, the compounds are capable of extending the lifespan of C. elegans. OFA and OFB possess both anti-neurodegeneration and anti-aging activities, supporting its therapeutic potential for the treatment of age-related neurodegenerative diseases which need to be studied in more detail in intervention studies.
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Backgroud: Renal fibrosis is the common characteristic of chronic kidney disease. Circular RNA plays an essential role in the occurrence and development of Renal fibrosis, but its regulative mechanism remains elusive. Methods: The animal and cell model of Renal fibrosis was established, and RNA-sequencing and real-time polymerase chain reaction (qRT-PCR) experiments were implemented. Subsequently, experiments for detecting apoptosis and proliferation of cell, were carried out, and the isobaric tags for relative and absolute quantification proteomics analyses were performed accordingly. Results: It was found that a newly discovered Circular RNA (circRNA_0002158), is highly expressed in kidneys or cells with fibrosis, implying that this Circular RNA might be associated with the occurrence and development of Renal fibrosis. Subsequently, the overexpression and knockdown of circRNA_0002158 were conducted in the human kidney epithelial cell line (HK-2) cells, and the results indicated that the circRNA_0002158 could inhibit apoptosis, and promote proliferation of cells. The kidney injury-related factors, including Fibronectin and plasminogen activator inhibitor-1 (PAI-1), were decreased in HK-2 cells with overexpression of circRNA_0002158, while the results were reversed in cells with knockdown of circRNA_0002158. Finally, to explore the regulative mechanism of circRNA_0002158, the iTRAQ proteomics analyses were implemented for the cell samples with OE of circRNA_0002158 and its control, it showed that multiple genes and functional pathways were associated with the occurrence and development of Renal fibrosis. Conclusion: CircRNA_0002158 is associated with regulating Renal fibrosis, and may contribute to ameliorating the progression of Renal fibrosis in the future.
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BACKGROUND: Sarcopenia is a progressive generalized skeletal muscle disorder that causes the accelerated loss of muscle mass and function. Osteoporosis is a systemic condition of the skeleton that results in low bone mass and quality. Several studies have suggested that osteoporosis and sarcopenia are interrelated; however, a few studies indicate the lack of a significant association between sarcopenia and osteoporosis. We aimed to evaluate the association between sarcopenia and osteoporosis via a systematic review and pooled analysis. METHODS: From the inception of the PubMed and Embase databases until September 2022, we conducted a systematic search for studies evaluating the relationship between sarcopenia and osteoporosis. Study appraisal and synthesis methods: We included observational studies that provided 95% confidence intervals (CIs) and risk estimates. Two reviewers independently extracted data and assessed the quality of the research. The random-effects model was applied to the pool analysis, and the odds ratios (ORs) and 95% CIs were finally calculated. RESULTS: The primary statistic was the mutual risk between sarcopenia and osteoporosis. According to the inclusion criteria, 56 studies (796,914 participants) were finally included. Sarcopenia was significantly correlative to the risk of osteoporosis (OR, 3.06; 95% CI, 2.30-4.08), and each standard deviation increase in relative appendicular skeletal muscle mass was significantly related to a decreased risk of osteoporosis (OR, 0.65; 95% CI, 0.56-0.75). Osteoporosis observably referred to a higher risk of sarcopenia (OR, 2.63; 95% CI, 1.98-3.49). CONCLUSION: Our research indicated that sarcopenia and osteoporosis are highly positively correlated. Osteoporosis is closely associated with the risk of sarcopenia. Our finding highlights the importance of sarcopenia screening for those at risk of osteoporosis, and vice versa. However, heterogeneity was noted among the studies, and this might have influenced the accuracy of the results. Therefore, the results of our study should be interpreted with caution.
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Osteoporose , Sarcopenia , Humanos , Sarcopenia/complicações , Sarcopenia/epidemiologia , Sarcopenia/diagnóstico , Osteoporose/etiologia , Razão de ChancesRESUMO
Neurodegenerative diseases are linked to neuronal cell death and neurite outgrowth impairment that are often caused by oxidative stress. Natural products, which have neuroprotective against oxidative stress and neurite outgrowth inducing activity, could be potential candidates for alternative treatment of neurodegenerative diseases. This study aims to investigate the neuroprotective effects and neuritogenesis properties of Anacardium occidentale leaf extracts in cultured neuronal (HT22 and Neuro-2a) cells. We found gallic acid, catechin and quercetin as the main compounds in A. occidentale extracts. The extracts have a protective effect against glutamate/H2O2-mediated oxidative stress-induced cell toxicity. The gene expression of cellular antioxidant enzymes (SODs, GPx and, GSTs) were up-regulated by this treatment. The treatment also triggered SIRT, Nrf2 proteins as well as the mRNA transcriptions of relevant anti-oxidation genes (NQO1, GCLM, and EAAT3). We demonstrated that the extracts promote antioxidant defense in neuronal cells via the SIRT1/Nrf2 signaling pathway. Moreover, the extracts increase neurite outgrowth and Ten-4 expression in Neuro-2a cells. However, the neuritogenesis properties did not occur, when Ten-4 expression was knocked down by corresponding siRNA. These results suggest that the leaf extracts have an interesting neuritogenesis and neuroprotective potential against glutamate/H2O2-mediated toxicity and could be a potential therapeutic candidate for neurodegenerative diseases.
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Vitis vinifea has been used for traditional medicines, food, beverages, and dietary antioxidant supplements. The chemical compositions and biological activities of the fruits and seeds have been extensively investigated. However, the biological effects of the leaves are limited, and its anti-neurodegeneration or antiaging activities are little known. The current work aims to study the beneficial effects of V. vinifera leaf extract on neuroprotective effects in HT22 cells, antiaging, and oxidative stress resistance properties in the Caenorhabditis elegans model. The ethanol extract was characterized by phytochemical composition using gas/liquid chromatography-mass spectrometry and reversed-phase high-performance liquid chromatography. The beneficial effects of V. vinifera ethanol (VVE) extract on antioxidant properties, neuroprotective effects, and the underlying mechanisms were studied by in vitro and in vivo studies. In HT22 cells, we found that VVE has a protective effect against glutamate-mediated oxidative stress-induced cell death. The gene expression of cellular antioxidant enzymes such as CAT, SODs, GSTs, and GPx was upregulated by VVE treatment. Moreover, VVE was also shown to alleviate oxidative stress and attenuate reactive oxygen species accumulation in C. elegans. We demonstrated that VVE could upregulate the expression of stress-response genes gst-4 and sod-3 and downregulate the expression of hsp-16.2. Our results suggest that the oxidative stress resistance properties of VVE are possibly involved in DAF-16/FoxO transcription factors. VVE reduced age-related markers (lipofuscin) while did not extend the life span of C. elegans under normal conditions. This study reports the neuroprotective effect and antioxidant activity of V. vinifera leaf extract and suggests its potential as a dietary or alternative supplement to defend against oxidative stress and age-related diseases.
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Oxidative stress plays a crucial role in the development of age-related neurodegenerative diseases. Previously, Glochidion zeylanicum methanol (GZM) extract has been reported to have antioxidant and anti-aging properties. However, the effect of GZM on neuroprotection has not been reported yet; furthermore, the mechanism involved in its antioxidant properties remains unresolved. The study is aimed to demonstrate the neuroprotective properties of GZM extract and their underlying mechanisms in cultured neuronal (HT-22 and Neuro-2a) cells and Caenorhabditis elegans models. GZM extract exhibited protective effects against glutamate/H2O2-induced toxicity in cultured neuronal cells by suppressing the intracellular reactive oxygen species (ROS) generation and enhancing the expression of endogenous antioxidant enzymes (SODs, GPx, and GSTs). GZM extract also triggered the expression of SIRT1/Nrf2 proteins and mRNA transcription of antioxidant genes (NQO1, GCLM, and EAAT3) which are the master regulators of cellular defense against oxidative stress. Additionally, GZM extract exhibited protective effects to counteract ß-amyloid (Aß)-induced toxicity in C. elegans and promoted neuritogenesis properties in Neuro-2a cells. Our observations suggest that GZM leaf extract has interesting neuritogenesis and neuroprotective potential and can possibly act as potential contender for the treatment of oxidative stress-induced Alzheimer's disease (AD) and related neurodegenerative conditions; however, this needs to be studied further in other in vivo systems.
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Lanthanide(III)-based luminescent materials have attracted great research interests due to their unique optical, electronic, and chemical characteristics. Up to now, how to extend these materials into large, broad application fields is still a great challenging task. In this contribution, we are intended to present a simple but facile strategy to enhance the luminescence from lanthanide ions and impart lanthanide(III)-based luminescent materials with more applicable properties, leading to meet the requirements from different purposes, such as being used as highly emissive powders, hydrogels, films, and sensitive probes under external stimuli. Herein, a water soluble, blue color emissive, temperature sensitive, and film-processable copolymer (Poly-ligand) was designed and synthesized. Upon complexing with Eu3+ and Tb3+ ions, the red color-emitting Poly-ligand-Eu and green color-emitting Poly-ligand-Tb were produced. After finely tuning the ratios between them, a standard white color emitting Poly-ligand-Eu1:Tb4 (CIE = 0.33 and 0.33) was obtained. Furthermore, the resulted materials not only possessed the emissive luminescent property but also inherited functions from the copolymer of Poly-ligand. Thus, these lanthanide(III)-based materials were used for fingerprint imaging, luminescent soft matters formation, colorful organic light-emitting diode device fabrication, and acid/alkali vapors detection.
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Oolong tea, a traditional Chinese tea, is especially popular in south China and has a variety of health benefits. However, studies about its neuroprotective and neuroregenerative properties are still limited. This study explored the neuroprotective and neurite outgrowth-promoting properties of oolong tea in cultured neuronal cells (Neuro-2a and HT22) and Caenorhabditis elegans models. Ultra performance liquid chromatography was applied to identify the main natural bioactive compounds in oolong tea. Using Neuro-2a and HT22 cells, we found that oolong tea extracts had a protective effect against glutamate-induced cell death. The extracts reduced intracellular reactive oxygen species accumulation and induced gene expression of cellular antioxidant enzymes such as GPx, GSTs and SODs. These extracts also increased the average neurite length, and GAP-43 and Ten-4 mRNA expression in Neuro-2a cells. Moreover, they had protective effects against Aß-induced paralysis, chemotaxis deficiency and α-synuclein aggregation in C. elegans. This is the first study showing the neuroregenerative and neuroprotective potential of the oolong tea extracts against glutamate/Aß/α-synuclein-induced toxicity in vitro and in vivo. Our study may support oolong tea extracts as potential candidates for the prevention of neurodegenerative diseases.
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Peptídeos beta-Amiloides/toxicidade , Caenorhabditis elegans/efeitos dos fármacos , Camellia sinensis/química , Ácido Glutâmico/efeitos adversos , Doenças Neurodegenerativas/prevenção & controle , Neurônios/efeitos dos fármacos , Extratos Vegetais/administração & dosagem , Peptídeos beta-Amiloides/metabolismo , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Células Cultivadas , Feminino , Humanos , Masculino , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Neuroproteção/efeitos dos fármacos , Fármacos Neuroprotetores , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Chá/químicaRESUMO
Lithium-sulfur (Li-S) batteries are considered the most appealing secondary batteries attributed to the ultrahigh theoretical specific capacity as 1675 mA·h·g-1 for elemental sulfur cathode. Nevertheless, there are still several disadvantages (sulfur insulation, insoluble lithium polysulfide, shuttle effect, etc.) impeding the commercial application of Li-S batteries. Recent studies have discovered that nanosized metal oxides can effectively modify the electrochemical properties of composite cathodes in Li-S batteries. In this paper, graphene aerogels (GA) loaded with different mass fractions of antimony tin oxide (ATO) nanoparticles were incorporated with sulfur and utilized as cathode materials for Li-S batteries. The sample (GA/ATO-3) loaded with 3 wt.% ATO nanoparticles showed the best electrochemical performance. For example, the specific discharge capacity of first cycle reached 1210 mA·h·g-1 under a current of 0.1 C. The reversible discharge capacity was reduced to 545 mA·h·g-1 after 50 cycles, namely, the corresponding capacity retention rate was approximately 50%. However, the coulombic efficiency was still near 100%. Potential modification mechanism was considered to be a combination between the GA with excellent conductivity, which effectively improved the internal conductivity of the cathode material, and the ATO nanoparticles, which improved the distribution uniformity of the solid sulfur and its sulfurized product because the ATO nanoparticles acted as heterogeneous nucleation points. Furthermore, the ATO nanoparticles with strong polarity possessed a strong capture ability on the soluble polysulfide ions. For the above reasons, the ATO-loaded GA cathode could effectively inhibit the "shuttle effect," thereby, improved the electrochemical performance of Li-S batteries.
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In comparison with fluorescence molecules with aggregation-caused quenching (ACQ), fluorescence molecules with aggregation-induced emission (AIE) have great advantages in cell imaging, image-guided photodynamic therapy (PDT), and antibacterial activity. However, the reasonable design and synthesis of related molecules are still of great challenges. Herein, a consecutive strategy via several reliable reactions to prepare a series of AIE-active luminogens by adjusting their structures is reported. Having concentrated on the factors for the principle purpose of 1O2 generation, TPA-18 is picked out within all triphenylamine (TPA) derivatives according to its longer emission wavelength (640 nm in solid), the lowest energy gap between HOMO and LUMO (calculated as 2.04 eV), the totally separated orbital distributions of HOMO and LUMO, and typical AIE characteristics. Meanwhile, owing to the presence of the positive structural charge and the bright emission color, TPA-18 in aggregated form is detected as an impressive probe for the mitochondria-targeted imaging and living zebrafish embryos imaging in vivo. Accordingly, TPA-18 can effectively generate 1O2 reactive oxygen species; it provides an effective application for image-guided photodynamic cancer treatment and antibacterial activity. Therefore, this study not only synthesized AIE photosensitizer with tunable emission wavelength (from blue to red color) but also raised a new concept for the constructing AIEgens with versatile applications in cell imaging, antibacterial activity, and image-guided PDT.