RESUMO
Edible bird's nest (EBN) is an expensive health food. There are many adulterants in the market. It remains challenging to discriminate EBN from its adulterants due to a lack of high-specificity markers. Besides, the current markers are confined to soluble fraction of EBN. Here, both soluble and insoluble fractions were analyzed by LC-QTOF-MS/MS. A total of 26 high-specificity peptides that were specific to EBN were selected as qualitative authentication markers. Among them, 10 markers can discriminate EBN from common adulterants, 13 markers discriminate white EBN from grass EBN/common adulterants, and 3 markers discriminate grass EBN from white EBN/common adulterants. Three of them, which showed high signal abundance (Peak area ≥ 106) and satisfactory linearity (R2 ≥ 0.995) with EBN references, were selected as the assay marker; and their peptide sequences were confidently identified by searching database/de novo sequencing. Based on these markers, a qualitative and quantitative analytical method was successfully developed and well-validated in terms of linearity, precision, repeatability, and accuracy. The method was subsequently applied to detect EBN products on the market. The results indicated that more than half of EBN products were not consistent with what the merchants claimed.
Assuntos
Aves , Espectrometria de Massas em Tandem , Sequência de Aminoácidos , Animais , Cromatografia Líquida , Peptídeos , Espectrometria de Massas em Tandem/métodosRESUMO
Donkey-hide gelatin, also called Ejiao (colla corii asini), is commonly used as a food health supplement and valuable Chinese medicine. Its growing popular demand and short supply make it a target for fraud, and many other animal gelatins can be found as adulterants. Authentication remains a quality concern. Peptide markers were developed by searching the protein database. However, donkeys and horses share the same database, and there is no specific marker for donkeys. Here, solutions are sought following a database-independent strategy. The peptide profiles of authentic samples of different animal gelatins were compared using LC-QTOF-MS/MS. Fourteen specific markers, including four donkey-specific, one horse-specific, three cattle-specific, and six pig-specific peptides, were successfully found. As these donkey-specific peptides are not included in the current proteomics database, their sequences were determined by de novo sequencing. A quantitative LC-QQQ multiple reaction monitoring (MRM) method was further developed to achieve highly sensitive and selective analysis. The specificity and applicability of these markers were confirmed by testing multiple authentic samples and 110 batches of commercial Ejiao products, 57 of which were found to be unqualified. These results suggest that these markers are specific and accurate for authentication purposes.
Assuntos
Gelatina , Espectrometria de Massas em Tandem , Animais , Biomarcadores/análise , Bovinos , Equidae , Gelatina/análise , Cavalos , Peptídeos/análise , Suínos , Espectrometria de Massas em Tandem/métodosRESUMO
Acetylation of NF-κB's RelA subunit at lysine-310 (AcLys310) helps to maintain constitutive NF-κB activity in cancers such as triple-negative breast cancer (TNBC). Bromodomain-containing factor BRD4 binds to acetylated RelA to promote the activity of NF-κB. Hence, interfering with the acetylated RelA-BRD4 interaction is a potential strategy for treating NF-κB-driven TNBC. Here, a new compound 13a was obtained by structural optimization and modification of our previously reported compound. In comparison with the well-known BRD4 inhibitor (+)-JQ1, 13a showed more potent anticancer activity in NF-κB-active MDA-MB-231 cells. Mechanistically, 13a antagonized the protein-protein interaction (PPI) between BRD4 and acetylated RelA, decreased levels of IL-6, IL-8, Snail, Vimentin, and ZEB1, induced cell senescence and DNA damage, and weakened the adhesion, metastasis, and invasion ability of TNBC cells. Our results provide insights into avenues for the further development of potent BRD4-acetylated RelA PPI inhibitors. Moreover, our findings highlight the effectiveness and feasibility of blocking the interaction between BRD4 and acetylated RelA against NF-κB-active cancers, and of screening antagonists of this PPI.
Assuntos
Antineoplásicos/farmacologia , Proteínas de Ciclo Celular/antagonistas & inibidores , Indóis/farmacologia , NF-kappa B/antagonistas & inibidores , Ácidos Pentanoicos/farmacologia , Fatores de Transcrição/antagonistas & inibidores , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Antineoplásicos/síntese química , Antineoplásicos/química , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Indóis/química , Modelos Moleculares , Estrutura Molecular , NF-kappa B/metabolismo , Ácidos Pentanoicos/química , Relação Estrutura-Atividade , Fatores de Transcrição/metabolismo , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologiaRESUMO
BACKGROUND Atrial fibrillation (AF) is the most prevalent arrhythmia worldwide. Although it is not life-threatening, the accompanying rapid and irregular ventricular rate can lead to hemodynamic deterioration and obvious symptoms, especially the risk of cerebrovascular embolism. Our study aimed to identify novel and promising genes that could explain the underlying mechanism of AF development. MATERIAL AND METHODS Expression profiles GSE41177, GSE79768, and GSE14975 were acquired from the Gene Expression Omnibus Database. R software was used for identifying differentially expressed genes (DEGs), and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were subsequently performed. A protein-protein interaction network was constructed in Cytoscape software. Next, a least absolute shrinkage and selection operator (LASSO) model was constructed and receiver-operating characteristic curve analysis was conducted to assess the specificity and sensitivity of the key genes. RESULTS We obtained 204 DEGs from the datasets. The DEGs were mostly involved in immune response and cell communication. The primary pathways of the DEGs were related to the course or maintenance of autoimmune and chronic inflammatory diseases. The top 20 hub genes (high scores in cytoHubba) were selected in the PPI network. Finally, we identified 6 key genes (FCGR3B, CLEC10A, FPR2, IGSF6, S100A9, and S100A12) via the LASSO model. CONCLUSIONS We present 6 target genes that are potentially involved in the molecular mechanisms of AF development. In addition, these genes are likely to serve as potential therapeutic targets.
Assuntos
Fibrilação Atrial/genética , Redes Reguladoras de Genes/genética , Mapas de Interação de Proteínas/genética , Fibrilação Atrial/fisiopatologia , Biomarcadores Tumorais/genética , Biologia Computacional/métodos , Bases de Dados Genéticas , Perfilação da Expressão Gênica/métodos , Regulação Neoplásica da Expressão Gênica/genética , Ontologia Genética , Humanos , MicroRNAs/genética , Mapeamento de Interação de Proteínas/métodos , Software , Transcriptoma/genéticaRESUMO
The biological activities of water-soluble components of edible mushroom Rubinoboletus ballouii (RB) were seldom reported. Polysaccharides of RB (RBP) were prepared and well-characterized using chemical analyses. The immunomodulatory properties of RBP were investigated using human monocyte-derived dendritic cells (moDC) in vitro, and cyclophosphamide (CTX)-induced immunosuppressive mouse model. Results showed that RBP was found to contain 80.6% (w/w) of neutral sugars including D-fucose, D-mannose, D-glucose and D-galactose (1.7:1.4:1.0:1.8), and 12.5% (w/w) of proteins, which composed of glutamine, threonine, serine, etc. RBP could promote the maturation of moDC and increase the secretion of IL-12p40, IL-10, and TNF-α. Furthermore, the stimulation of IL-12p40 production was inhibited by pretreatment with toll-like receptor (TLR)-4 blocker or NF-κB pathway blocker, suggesting that the activation of moDC by RBP was mediated through NF-κB pathway via TLR-4 receptor. On the other hand, in CTX-treated mice, RBP restored the loss of CD34bright CD45dim hematopoietic stem cells and increased IL-2 production in sera and splenocytes culture supernatant, as well as up-regulated the percentage of CD4+ T helper lymphocyte in mice splenocytes. These findings strongly suggested that RBP are the active ingredients of RB responsible for its immunostimulatory actions and deserved to be further investigated as cancer supplements.
Assuntos
Basidiomycota/química , NF-kappa B/metabolismo , Polissacarídeos/uso terapêutico , Receptor 4 Toll-Like/metabolismo , Animais , Humanos , Camundongos , Polissacarídeos/farmacologiaRESUMO
INTRODUCTION: Therapy for human hepatocellular carcinoma (HCC) remains a great challenge for physicians and patients worldwide. The anti-tumor effects of reversine have attracted much more concerns. MATERIALS AND METHODS: This study evaluated the growth regulatory effects of reversine on HCC cells lines. Meanwhile, the underlying mechanism including autophagy modulation was also identified. RESULTS: reversine markedly inhibited the proliferation of both HCC cells and induced cell apoptosis and multinuclear in a dose-dependent manner. In addition, the decreased ratio of LC3II/LC3I as well as elevated p62 expression were observed under reversine treatment, indicating the autophagy inhibition by reversine in HepG2 cell line. Moreover, modulation of autophagy with rapamycin and chloroquine significantly attenuated and enhanced the cytostatic effects of reversine, respectively. CONCLUSIONS: reversine could reduce the cell viability of HCC cells via inducing cell apoptosis and polyploidy. In addition, cell autophagy was involved and might play a protective role in HCC cells, the joint use of autophagy inhibitor enhanced reversine-mediating antitumor effects. Our data offered novel ideas for comprehensive therapeutic regimes on human hepatocellular carcinoma.
Assuntos
Autofagia , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Morfolinas/farmacologia , Purinas/farmacologia , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Hep G2 , Humanos , Poliploidia , Ensaio Tumoral de Célula-TroncoRESUMO
Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 has become an important public health issue in the world. More than 118 000 cases were confirmed around the world. The main clinical manifestations were respiratory symptoms and occasional gastrointestinal symptoms. However, there is no unified standard for the diagnosis and treatment of COVID-19. In the retrospective analysis, we report nine cases of COVID-19, describe the history of contact, clinical manifestations, the course of diagnosis and clinical treatment before, during and after treatment.
Assuntos
Betacoronavirus/genética , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/tratamento farmacológico , Interferon alfa-2/uso terapêutico , Pneumonia Viral/diagnóstico , Pneumonia Viral/tratamento farmacológico , RNA Viral/genética , Adolescente , Adulto , Betacoronavirus/efeitos dos fármacos , Betacoronavirus/isolamento & purificação , Betacoronavirus/patogenicidade , COVID-19 , Teste para COVID-19 , China , Técnicas de Laboratório Clínico/métodos , Busca de Comunicante , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/patologia , Feminino , Humanos , Lopinavir/uso terapêutico , Masculino , Metilprednisolona/uso terapêutico , Pessoa de Meia-Idade , Moxifloxacina/uso terapêutico , Orofaringe/virologia , Oxigênio/uso terapêutico , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/patologia , RNA Viral/isolamento & purificação , Estudos Retrospectivos , Ritonavir/uso terapêutico , SARS-CoV-2 , Índice de Gravidade de Doença , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/virologia , Tomografia Computadorizada por Raios XRESUMO
In recent years, transition metal complexes with their prominent photophysical properties have emerged as versatile chemosensors to probe different target analytes, including metal ions. By incorporating specific metal ion receptors, various iridium(III) complex-based cation sensors have been developed using different mechanisms. In this review, we survey examples of iridium(III) complex-based metal ion chemosensors that have been reported in the literature. Their design, mechanism and outlook will also be discussed.
Assuntos
Cátions/análise , Técnicas de Química Analítica/métodos , Complexos de Coordenação/análise , IrídioRESUMO
In this work, sponge impregnated with iron pentacarbonyl was utilized to obtain a novel composite in which the carbonyl iron (CI) was embedded in a graphitized carbon matrix (CI-C). The CI that results from the thermal pyrolysis of iron pentacarbonyl can homogeneously disperse into the pore structures of the sponge skeleton, which not only improves the stability of the CI, but also modifies the impedance matching character. Moreover, the sponge bulk turns into graphitized carbon during the heat treatment (graphitized catalysis of magnetic metal on carbon at high temperature). Due to the respective strong dissipation ability of CI and the graphitized carbon matrix, the as-prepared CI-C sample exhibits a good microwave absorption performance, including expanding the effective absorption bandwidth and reduced weight, compared to pure CI. Moreover, the sample with 30 wt% paraffin loading not only shows strong reflection loss absorbing ability, but also possesses continuous dual-absorption peaks (9.96 GHz, -38.7 dB, and 13.8 GHz is -37.6 dB). This work not only extends the application of carbonyl iron as a lightweight microwave absorber with dual-absorption peaks but also initiates a new approach for artificially designed carbon-based composites via a simple sponge-impregnation method.
RESUMO
BACKGROUND High rates of HBeAg and/or HBsAg seroconversion or clearance have been achieved in chronic hepatitis B (CHB) patients receiving pegylated interferon (pegIFN) in addition to ongoing nucleos(t)ide analogue (NUC) treatment. In the present study, we aimed to evaluate HBsAg kinetics to predict HBeAg seroconversion and HBsAg clearance in these patients. MATERIAL AND METHODS A total of 33 HBeAg-positive and 17 HBeAg-negative patients were enrolled between January 2010 and January 2018. At the end of pegIFN treatment, 9 of 50 patients achieved HBsAg clearance, and 9 of 33 HBeAg-positive patients achieved HBeAg seroconversion. RESULTS The cutoff value of 0.41 log10 IU/mL in HBsAg decline at week 12 had a positive predictive value (PPV) of 58.3% and a negative predictive value (NPV) of 94.6% for HBsAg clearance. The cutoff value of 1.94 log10 IU/mL in HBsAg decline at week 24 had a PPV of 80.0% and an NPV of 97.5% for HBsAg clearance. The cutoff value of 0.47 log10 IU/mL in HBsAg decline at week 12 had a PPV of 83.3% and an NPV of 85.2% for HBeAg seroconversion. The cutoff value of 1.29 log10 IU/mL in in HBsAg decline at week 24 had a PPV of 85.7% and an NPV of 88.5% for HBeAg seroconversion. CONCLUSIONS Early HBsAg drop has a high predictive value for HBsAg clearance and HBeAg seroconversion in patients who were treated with combination therapy of pegIFN and NUCs.
Assuntos
Antígenos de Superfície da Hepatite B/análise , Hepatite B Crônica/tratamento farmacológico , Adulto , Antivirais/uso terapêutico , Biomarcadores Farmacológicos/sangue , DNA Viral/sangue , Feminino , Guanina/análogos & derivados , Antígenos de Superfície da Hepatite B/sangue , Antígenos de Superfície da Hepatite B/metabolismo , Antígenos E da Hepatite B/sangue , Antígenos E da Hepatite B/metabolismo , Vírus da Hepatite B/genética , Hepatite B Crônica/sangue , Humanos , Interferon alfa-2/farmacocinética , Interferon alfa-2/farmacologia , Interferon-alfa/farmacologia , Masculino , Pessoa de Meia-Idade , Polietilenoglicóis/farmacologia , Proteínas Recombinantes/farmacologia , Soroconversão , Resultado do TratamentoRESUMO
Due to role of the Keap1-Nrf2 protein-protein interaction (PPI) in protecting cells from oxidative stress, the development of small molecule inhibitors that inhibit this interaction has arisen as a viable approach to combat maladies caused by oxidative stress, such as cancers, neurodegenerative disease and diabetes. To obtain specific and genuine Keap1-Nrf2 inhibitors, many efforts have been made towards developing new screening approaches. However, there is no inhibitor for this target entering the clinic for the treatment of human diseases. New strategies to identify novel bioactive compounds from large molecular databases and accelerate the developmental process of the clinical application of Keap1-Nrf2 protein-protein interaction inhibitors are greatly needed. In this review, we have summarized virtual screening and other methods for discovering new lead compounds against the Keap1-Nrf2 protein-protein interaction. We also discuss the advantages and limitations of different strategies, and the potential of this PPI as a drug target in disease therapy.
Assuntos
Descoberta de Drogas/métodos , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Bibliotecas de Moléculas Pequenas/uso terapêutico , Diabetes Mellitus/metabolismo , Diabetes Mellitus/prevenção & controle , Humanos , Neoplasias/metabolismo , Neoplasias/prevenção & controle , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/prevenção & controle , Estresse Oxidativo/efeitos dos fármacos , Ligação Proteica/efeitos dos fármacosRESUMO
Platinum-based drugs have revolutionized cancer care, but are unfortunately associated with various adverse effects. Meanwhile, natural product scaffolds exhibit multifarious bioactivities and serve as an attractive resource for cancer therapy development. Thus, the conjugation of natural product scaffolds to metal complexes becomes an attractive strategy to reduce the severe side effects arising from the use of metal bearing drugs. This review aims to highlight the recent examples of natural product-conjugated metal complexes as cancer therapies with enhanced selectivity and efficacy. We discuss the mechanisms and features of different conjugate complexes and present an outlook and perspective for the future of this field.
Assuntos
Produtos Biológicos/uso terapêutico , Complexos de Coordenação/uso terapêutico , Metais/uso terapêutico , Neoplasias/tratamento farmacológico , Animais , Produtos Biológicos/química , Complexos de Coordenação/química , Humanos , Metais/efeitos adversosRESUMO
Macrophages occur in polarized phenotypes, whose characteristics determine the role they play in tumor growth. The M1 phenotype macrophages promote tumoricidal responses and suppress tumor growth. Our previous study showed that a polysaccharide isolated from Radix Astragali, named RAP, was itself non-cytotoxic but induced RAW264.7 cells' cytotoxicity against cancer cells. The current study was undertaken to determine its mechanism. Series studies was conducted to show that RAP is able to induce much higher gene expression of M1 markers, including iNOS, IL-6, TNF-a, and CXCL10, compared with the control group. When RAP-induced BMDMs were transplanted together with 4T1 tumor cells in BALB/c mice, both tumor volume and tumor weight decreased. Further studies indicated that RAP induces the Notch signaling pathway in RAW264.7 cells. The function of Notch signaling in macrophage polarization was confirmed by using γ-secretase inhibitor. These results suggested that Astragalus polysaccharide RAP induces macrophage's polarization to M1 phenotype via the Notch signaling pathway.
Assuntos
Astrágalo/química , Polaridade Celular , Macrófagos/citologia , Macrófagos/metabolismo , Polissacarídeos/farmacologia , Receptores Notch/metabolismo , Transdução de Sinais , Animais , Biomarcadores/metabolismo , Linhagem Celular Tumoral , Polaridade Celular/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Fenótipo , Células RAW 264.7 , Carga Tumoral/efeitos dos fármacosRESUMO
Increasing efforts have recently been devoted to the artificial design and function of nanostructures for their application prospects in catalysis, drug delivery, energy storage, and microwave absorption. With the advantages of natural abundance, low cost, and environment friendliness, a one-dimensional (1D) MnO2 nanowire (MW) is the representative dielectric-loss absorber for its special morphology and crystalline structure. However, its low reflection loss (RL) value due to its thin thickness limits its wide development and application in the microwave absorption field. In this work, artificially designed MnO2@AIR@C (MCs), namely, 1D hollow carbon nanotubes filled with nano-MnO2, were designed and synthesized. It is found that the RL value of the MC is almost lower than -10 dB. Furthermore, the RL value was able to achieve -18.9 dB with an effective bandwidth (-10 dB) of 5.84 GHz at 2.25 mm. Simultaneously, the dielectric and interfacial polarization became stronger while the impedance matching was much better than in the single MWs. Hence, the rational design and fabrication of micro-architecture are essential and MC has great potential to be an outstanding microwave absorber.
RESUMO
BACKGROUND We explored the possible relationship between Modic changes (MCs) and sagittal parameters of the cervical spine. MATERIAL AND METHODS We enrolled 150 patients with cervical MC on the magnetic resonance imaging (MRI) scans in the MC (+) group and divided them into 3 sub-groups with 50 patients each: the MC1 sub-group, the MC2 sub-group, and the MC3 sub-group. Another 150 healthy subjects receiving routine health examinations were also enrolled in the study as the MC (-) group. The sagittal parameters in the cervical spine were measured and compared and multiple logistic regression analysis was performed to analyze the risk factor for the occurrence of MC. RESULTS Four cervical sagittal parameters were measured and compared between all the enrolled groups, including neck tilt (NT), T1 slope (T1s), thoracic inlet angle (TIA), and Cobb C2-C7. The results confirmed that the parameter of Cobb C2-C7 was much smaller in the MC(+) group when compared with that in the MC(-) group (P<0.05), while no significant differences were detected between the MC(+) and MC(-) groups for the parameters of NT, T1 T1s, and TIA (P>0.05). Multiple logistic regression analysis showed that Cobb C2-C7 (less than 8.5°) could be regarded as the risk factor for the occurrence of MC, and the receiver operating characteristic (ROC) curve showed that moderate diagnostic significance was obtained with an area under curve (AUC) of 0.82. CONCLUSIONS The present study demonstrated that Cobb C2-C7 (less than 8.5°) is a potential risk factor for the development of MC.
Assuntos
Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/patologia , Adulto , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Pescoço/diagnóstico por imagem , Pescoço/patologia , Osteoartrite da Coluna Vertebral/diagnóstico por imagem , Curva ROC , Fatores de Risco , Vértebras Torácicas/diagnóstico por imagem , Vértebras Torácicas/patologiaRESUMO
Polysaccharides, which exert immunoregulatory effects, are becoming more and more popular as food supplements; however, certain components of ordinary foods could be reducing the polysaccharides beneficial effects. Quercetin, a flavonoid found in common fruits and vegetables, is one such component. This study investigated the effects of quercetin on Astragalus polysaccharide RAP induced-macrophage activation. The results show quercetin decreases the NO production and iNOS gene expression in RAW264.7 cells, and it inhibits the production of cytokines in RAW264.7 cells and peritoneal macrophages. Western blot analysis results suggest that quercetin inhibits the phosphorylation of Akt/mTORC1, MAPKs, and TBK1, but has no effect on NF-κB in RAP-induced RAW264.7 cells. Taken together, the results show that quercetin partly inhibits macrophage activation by the Astragalus polysaccharide RAP. This study demonstrates that quercetin-containing foods may interfere with the immune-enhancing effects of Astragalus polysaccharide RAP to a certain extent.
Assuntos
Astrágalo/química , Polissacarídeos/farmacologia , Animais , Ativação de Macrófagos/efeitos dos fármacos , Camundongos , NF-kappa B/metabolismo , Fosforilação/efeitos dos fármacos , Quercetina/farmacologia , Células RAW 264.7 , Transdução de Sinais/efeitos dos fármacosRESUMO
Extracellular vesicles have emerged as important mediators of intercellular communication and play an active role in cancer, including breast cancer. Despite limited studies, initial observations suggest that these vesicles are important in breast physiology and pathophysiology. We here, in brief, describe their potential use as future biomarkers and therapeutic agents in breast cancer. Extracellular vesicles in blood and breast fluid may have a great potential to detect and predict the presence of breast cancer, and extracellular vesicles modulation may emerge as a therapeutic approach in cancer therapy.
Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Vesículas Extracelulares/metabolismo , Vesículas Extracelulares/patologia , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/terapia , Linhagem Celular Tumoral , Feminino , Terapia Genética/métodos , Humanos , Células MCF-7RESUMO
Ni@C composites, which simultaneously possess porous, core-shell and 1D nanostructures have been synthesized with a facile self-template strategy. The precursors were obtained by a hydrothermal process using NiCl2 · 6H2O and nitrilotriacetic acid as the starting material and then annealed at 400 °C, 500 °C, and 600 °C. The Ni@C composites annealed at 500 °C display a nanorod feature with a length of â¼3 µm and diameter of 230-500 nm. In addition, about 3 nm carbon shells and 4 nm Ni cores can be found in Ni@C nanorods. Attributed to the interconnected mesoporous texture in nanorods, strengthened interfacial polarization from core-shell structure, and better impedance matching benefiting from a great deal of pores, Ni@C nanorod composites exhibit perfect microwave absorption performance. The minimum reflection loss (RL) value of -26.3 dB can be gained at 10.8 GHz with a thickness of 2.3 mm. Moreover, the effective bandwidth (RL ≤ -10 dB) can be achieved, 5.2 GHz (12.24-17.4 GHz) under an absorber thickness of 1.8 mm, indicating its great potential in the microwave absorption field. Considering this technique is facile and effective, our study may provide a good reference for the synthesis of 1D carbon-based microwave absorbers with core-shell nanostructure.
RESUMO
We synthesized a new europium complex [Eu(ecbpd)3 (Phen)] with bis(ß-diketone) ligand containing a carbazole group, in which ecbpd and Phen are dehydro-3,3'-(9-ethyl-9H-carbazole-3,6-diyl)bis(1-phenylpropane-1,3-dione) and 1,10-phenanthroline, respectively. Its UV/vis and photoluminescent spectra, quantum yield, luminescence lifetime, electrochemistry, thermal stability and electroluminescent performances were studied. This europium complex showed low efficiency luminescence, which is probably due to the mismatching energy levels of its ligand and Eu3+ , as well as the double Eu3+ core resonance.
Assuntos
Carbazóis/química , Técnicas Eletroquímicas , Európio/química , Cetonas/química , Luminescência , Compostos Organometálicos/química , Processos Fotoquímicos , Ligantes , Estrutura Molecular , Compostos Organometálicos/síntese química , TemperaturaRESUMO
Sanhuang Tablet (SHT) is a Chinese patented drug commonly used for the treatment of inflammations of the respiratory tract, gastrointestinal tract, and skin. It contains a special medicinal composition including the single compound berberine hydrochloride, extracts of Scutellariae Radix and Rhei Radix et Rhizoma, as well as the powder of Rhei Radix et Rhizoma. Despite advances in analytical techniques, quantitative evaluation of a Chinese patented drug like SHT remains a challenge due to the complexity of its chemical profile. In this study, ultra-high performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) was used to simultaneously quantify 29 non-sugar small molecule components of SHT (11 flavonoids, two isoflavonoids, one flavanone, five anthraquinones, two dianthranones, five alkaloids, two organic acids and one stilbene). Three major saccharide components, namely fructose, glucose, and sucrose, were also quantitatively determined using high performance liquid chromatography-charged aerosol detector (HPLC-CAD) on an Asahipak NH2P-50 4E amino column. The established methods were validated in terms of linearity, sensitivity, precision, accuracy, and stability, and then successfully applied to analyze 27 batches of commercial SHT products. A total of up to 57.61% (w/w) of SHT could be quantified, in which the contents of the determined non-saccharide small molecules varied from 5.91% to 16.83% (w/w) and three saccharides accounted for 4.41% to 48.05% (w/w). The results showed that the quality of the commercial products was inconsistent, and only four of those met Chinese Pharmacopoeia criteria.