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1.
Eur J Cancer ; 155: 85-96, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34371445

RESUMO

AIM: The prediction model of postoperative survival for single large and huge hepatocellular carcinoma (SLH-HCC, diameter > 5.0 cm) without portal vein tumour thrombus has not been well established. This study aimed to develop novel nomograms to predict postoperative recurrence and survival of these patients. METHODS: Data from 2469 patients with SLH-HCC who underwent curative resection from January 2005 to December 2015 in China were retrospectively collected. Specifically, nomograms of recurrence-free survival (RFS) and overall survival (OS) using data from a training cohort were developed with the Cox regression model (n = 1012). The modes were verified in an internal validation cohort (n = 338) and an external cohort comprising four tertiary institutions (n = 1119). RESULTS: The nomograms of RFS and OS based on tumour clinicopathologic features (diameter, differentiation, microvascular invasion, α-fetoprotein), operative factors (preoperative transcatheter arterial chemoembolisation therapy, scope of liver resection and intraoperative blood transfusion), underlying liver function (albumin-bilirubin grade) and systemic inflammatory or immune status (neutrophil-to-lymphocyte ratio) achieved high C-indexes of 0.85 (95% confidence interval [CI], 0.79-0.91) and 0.86 (95% CI, 0.79-0.93) in the training cohort, respectively, which were significantly higher than those of the five conventional HCC staging systems (0.62-0.73 for RFS, 0.63-0.75 for OS). The nomograms were validated in the internal cohort (0.83 for RFS, 0.84 for OS) and external cohort (0.87 for RFS, 0.88 for OS) and had well-fitted calibration curves. Our nomograms accurately stratified patients with SLH-HCC into low-, intermediate- and high-risk groups of postsurgical recurrence and mortality. CONCLUSIONS: The two nomograms achieved optimal prediction for postsurgical recurrence and OS for patients with SLH-HCC after curative resection.

2.
Phytother Res ; 35(8): 4555-4566, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34146352

RESUMO

Although clinically approved hepatitis B virus (HBV) polymerase inhibitors (lamivudine-3TC, entecavir, etc.) serve as effective therapeutics, the virus can easily generate resistance to them. Therefore, the treatment of HBV infection remains a public health problem. Numerous studies have shown that natural products have prospective anti-HBV activity. The purpose of this study was to isolate and extract des(rhamnosyl) verbascoside from Lindernia ruellioides (Colsm.) Pennell and explore its anti-HBV and hepatoprotective effects. Anti-HBV activity was evaluated in HepG2.2.15 cells, a human hepatocellular carcinoma cell line with HBV-stable infection, and its protective effect was evaluated in HL-7702 cells, a normal human liver cell line. HepG2.2.15 cells maintained normal growth morphology within the selected concentration range of des(rhamnosyl) verbascoside. It also inhibited the expression of HBV antigens and HBV DNA in a dose- and time-dependent manner in vitro. Further, western blot experiments showed that it could downregulate HBV X protein (HBx) expression in a dose-dependent manner. In the H2 O2 -induced hepatocyte injury model, the cell-survival rate of the HL-7702 cells with the highest drug dose reached 85.25%, which was significantly improved compared with that of the model group. Most of the cells returned to normal morphology, showing polygonal or fusiform structures. Thus, it may be stated that des(rhamnosyl) verbascoside exhibits anti-HBV activity and hepatoprotective effects in vitro and may exert an anti-HBV effect via antigen inhibition, HBV DNA secretion, and HBx protein expression.


Assuntos
Antivirais , Carcinoma Hepatocelular , Glucosídeos/farmacologia , Vírus da Hepatite B/efeitos dos fármacos , Lamiales/química , Neoplasias Hepáticas , Fenóis/farmacologia , Antivirais/farmacologia , Células Hep G2 , Humanos , Substâncias Protetoras/farmacologia , Replicação Viral/efeitos dos fármacos
3.
Int J Cancer ; 149(1): 127-138, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-33586134

RESUMO

The population of patients with huge hepatocellular carcinoma (H-HCC diameter > 10.0 cm) is an odd group that is not well adjudicated in the current staging systems, whose prognosis after curative resection varies. We aimed to develop novel models to predict the long-term outcomes of patients with H-HCC without portal vein tumor thrombus after hepatectomy. There were 1076 H-HCC patients enrolled who underwent curative liver resection in five institutions in China. In total, 670 patients were recruited from our center and randomly divided into the training cohort (n = 502) and internal validation (n = 168) cohorts. Additionally, 406 patients selected from other four centers as the external validation cohort. Novel models were constructed based on independent preoperative and postoperative predictors of postsurgical recurrence (PSR) and postsurgical mortality (PSM) determined in multivariable cox regression analysis. The predictive accuracy and discriminative ability of the model were measured using Harrell's concordance index (C index) and calibration curve and compared with five conventional HCC staging systems. PSR model and PSM model were constructed based on tumor number, microscopic vascular invasion, tumor differentiation, preoperative alpha-fetoprotein level, albumin-bilirubin grade, liver segment invasion, neutrophil-to-lymphocyte ratio or platelet-to-neutrophil ratio, and surgical margin or intraoperative blood transfusion. The C-indexes were 0.84 (95% CI, 0.78-0.90) and 0.85 (95% CI, 0.78-0.91) for the PSR and PSM models, respectively, which were substantially higher than those of the five conventional HCC staging systems (0.63-0.75 for PSR; 0.66-0.77 for PSM). The two novel models achieved more accurate prognostic predictions of PSR and PSM for H-HCC patients after curative liver resection.


Assuntos
Carcinoma Hepatocelular/patologia , Hepatectomia/mortalidade , Neoplasias Hepáticas/patologia , Modelos Estatísticos , Recidiva Local de Neoplasia/patologia , Nomogramas , Carcinoma Hepatocelular/cirurgia , China , Feminino , Seguimentos , Humanos , Neoplasias Hepáticas/cirurgia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/cirurgia , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida
4.
Phytochemistry ; 184: 112675, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33548770

RESUMO

Seven undescribed tirucallane-type triterpenoids, kumunorquassins A‒E and kumuquassins K and L, along with nine known analogues, have been isolated from the leaves of Picrasma quassioides (D. Don) Benn. Their structures and absolute configurations were elucidated based on comprehensive spectroscopic analyses, single-crystal X-ray diffraction analysis and electronic circular dichroism (ECD). The absolute configuration of cornusalterin J was unequivocally determined by X-ray diffraction based on its p-bromobenzoate derivative. A brief approach was presented in our study, which could rapidly and conveniently determine the relative and absolute configurations of OCH3-23 of kumuquassin L and cornusalterins J, H and G depending on the chemical shift differences (Δδ) of C-24 and C-25 and the chemical shifts of C-23, H-23 and H-24. In addition, the cytotoxicities of these compounds against two human tumour cell lines (HepG2 and Hep3B) were evaluated.


Assuntos
Picrasma , Triterpenos , Estrutura Molecular , Folhas de Planta , Triterpenos/farmacologia
5.
J Nat Prod ; 84(1): 20-25, 2021 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-33415978

RESUMO

The structural elucidation of chiral molecules with more than one stereocenter is usually a tricky problem. In this paper, efficient 1H NMR spectroscopic approaches for assigning the erythro and threo configurations of 1-oxygenated 1,2-diarylpropan-3-ols were developed. By analysis of the chemical shift differences of diastereotopic methylene H2-3 (Δδ3) in CDCl3 or the chemical shift differences of H-1 and H-2 (Δδ1,2) in methanol-d4, deuterated dimethyl sulfoxide, and acetone-d6, the configurations of 1-oxygenated 1,2-diarylpropan-3-ols can be rapidly and conveniently determined.


Assuntos
1-Propanol/química , Dimetil Sulfóxido/química , Oxigênio/química , Espectroscopia de Ressonância Magnética/métodos , Estereoisomerismo
6.
Bioorg Chem ; 104: 104314, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33011538

RESUMO

Small molecule accurate recognition technology (SMART) is an emerging method for the rapid structural prediction of major constituents from crude extracts and fractions. In the present study, a targeted isolation of an Elephantopus scaber extract by SMART resulted in the obtention of 15 new (1-15) and five known germacranolide sesquiterpenes (16-20). Their structures were assigned by extensively analyzing HRESIMS, NMR, X-ray crystallographic analyses, modified Mosher's method results, and quantum chemical calculate electronic circular dichroism (ECD) spectra. All germacranolide sesquiterpenes were screened to determine their inhibitory effects with two hepatoma cell lines (HepG2 and Hep3B), and compounds 14, 16, 18, 19 and 20 showed significant cytotoxic activities against the HepG2 (IC50, 3.3-9.9 µM) and Hep3B (IC50, 4.5-8.6 µM) cell lines. Further study suggested that 18 can induce the apoptosis of hepatoma cells via mitochondrial dysfunction.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Asteraceae/química , Extratos Vegetais/farmacologia , Sesquiterpenos de Germacrano/farmacologia , Bibliotecas de Moléculas Pequenas/farmacologia , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Modelos Moleculares , Estrutura Molecular , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Sesquiterpenos de Germacrano/química , Sesquiterpenos de Germacrano/isolamento & purificação , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/isolamento & purificação , Relação Estrutura-Atividade
7.
Phytochemistry ; 178: 112479, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32768717

RESUMO

Seven undescribed germacranolides, named as scabertopinolide A-G were obtained from whole herbs of Elephantopus scaber L. The determination of their structures was conducted via comprehensive spectroscopic analyses combined with experimental electronic circular dichroism (ECD) spectroscopic data and quantum mechanical ECD calculations. The absolute configuration of scabertopinolide A was determined by X-ray crystallography data analysis. The cytotoxicity of all compounds was evaluated against three human cancer cell lines HepG2, Hep3B (human hepatocellular carcinoma cell lines), and MCF-7 (human breast adenocarcinoma cell line). Scabertopinolide G exhibited the most significant cytotoxic activities against the three cancer cell lines with IC50 values between 7.0 and 10.3 µM. Furthermore, flow cytometry analysis has suggested that scabertopinolide G may cause death of cancer cells through apoptosis induction.


Assuntos
Antineoplásicos Fitogênicos , Antineoplásicos , Asteraceae , Neoplasias Hepáticas , Linhagem Celular Tumoral , Humanos , Sesquiterpenos de Germacrano
8.
Eur J Med Chem ; 198: 112362, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32371334

RESUMO

Chromatographic purification of Elephantopus scaber led to 16 new germacrane-type sesquiterpene lactones (1-16), named elephantopinolide A-P, along with a known analogue (17). Their structures were confirmed by comprehensive spectroscopic analyses, single-crystal X-ray diffraction, and comparison between the experimental and calculated ECD spectra. Their hepatocellular inhibition activities against Hep3B and HepG2 cells were screened by MTT assay, and the structure-activity relationships were examined. The results revealed that 10 (IC50 value of 2.83 µM and 1.98 µM) is more potent than sorafenib. The underlying mechanism study demonstrated that 10 could markedly induce apoptosis accompanied by increased ROS production and decreased mitochondrial membrane potential, resulting in the autophagy and G2/M phase cell arrest in Hep3B and HepG2 cells. Furthermore, signal pathways including MAPKs and AKT may play important roles in 10-induced hepatocellular carcinoma cells death.


Assuntos
Antineoplásicos/síntese química , Carcinoma Hepatocelular/tratamento farmacológico , Lactonas/química , Neoplasias Hepáticas/tratamento farmacológico , Magnoliopsida/química , Extratos Vegetais/síntese química , Sesquiterpenos/química , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Fase G2 , Humanos , Sistema de Sinalização das MAP Quinases , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Modelos Moleculares , Extratos Vegetais/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Sesquiterpenos de Germacrano/química , Relação Estrutura-Atividade
9.
Phytochemistry ; 175: 112361, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32289598

RESUMO

Seven undescribed terpenylated coumarins, named altissimacoumarin I-O, together with seven known compounds, altissimacoumarin C, altissimacoumarin E, altissimacoumarin G, altissimacoumarin H, puberulin, 7-(3-Methyl-2-butenyloxy)-6-methoxycoumarin and artelin were isolated from the root bark of Ailanthus altissima (Mill.) Swingle. Their structures were elucidated by comprehensive spectra data analysis, NMR calculation, DP4+ analysis and ACD/Structure Elucidator software simulation. The absolute configurations of altissimacoumarins K, L, M and N were determined by modified Mosher's method. All isolates were tested for their cytotoxic effect against two hepatoma carcinoma cell lines (HepG2, Hep3B). Altissimacoumarin C exhibited moderate cytotoxic effect against Hep3B cells, with IC50 of 45.21 µM.


Assuntos
Ailanthus , Cumarínicos , Casca de Planta , Extratos Vegetais
10.
Fitoterapia ; 143: 104559, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32199958

RESUMO

Four undescribed oxylipin vanillyl acetals with four stereogenic carbons were isolated from the herbs of Solanum lyratum. A comprehensive set of spectroscopic methods were used to elucidate the structures and relative configurations of 1-4. The absolute configurations of the naturally occurring compounds are assigned as 7S, 9'S, 10'S, 11'R at the site of six-membered cyclic acetal attachment by electronic circular dichroism (ECD) calculations and the modified Mosher's method. Compounds 1 and 3 displayed moderate selective inhibition against Hep3B and HepG2 cells, respectively. Further Annexin V-FITC/PI staining assay revealed that 1 and 3 might have inhibitory effects on hepatoma cells through induction of apoptosis.


Assuntos
Acetais/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Oxilipinas/farmacologia , Solanum/química , Acetais/isolamento & purificação , Antineoplásicos Fitogênicos/isolamento & purificação , Apoptose , China , Células Hep G2 , Humanos , Estrutura Molecular , Oxilipinas/isolamento & purificação , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia
11.
Bioorg Chem ; 95: 103545, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31927316

RESUMO

A phytochemical study on the roots of Daphne genkwa yielded seven new guaiane-type sesquiterpenoids (1-7), daphne A-G. Their structures were elucidated through comprehensive spectroscopic analyses. The absolute configurations were determined by comparison between experimental electronic circular dichroism (ECD) and calculated ECD spectra via time-dependent density functional theory (TDDFT) and the modified Mosher's method. Furthermore, all isolates were evaluated for their neuroprotective activities against H2O2-induced injury in human neuroblastoma SH-SY5Y cells. Among them, compounds 1 (78.42%) and 4 (79.34%) exhibited potent neuroprotective effects against H2O2-induced neurotoxicity at 25 µM. Further Annexin V-FITC/propidium iodide (PI) doubling staining exhibited that the neuroprotective effects of compounds 1 and 4 appeared to be mediated via suppressing cell apoptosis. Flow cytometry assays also proved that compounds 1 and 4 could attenuate mitochondrial dysfunction in SH-SY5Y cells.


Assuntos
Daphne/química , Descoberta de Drogas , Fármacos Neuroprotetores/farmacologia , Raízes de Plantas/química , Sesquiterpenos/farmacologia , Linhagem Celular Tumoral , Humanos , Mitocôndrias/efeitos dos fármacos , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/isolamento & purificação , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação
12.
J Chem Inf Model ; 59(10): 4393-4401, 2019 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-31585031

RESUMO

Cypridina bioluminescence has been increasingly used in bioimaging, bioanalysis, and biomedicine, due to high quantum yield and high signal-to-noise ratio. However, there is still no consensus regarding different aspects of the chemiluminescent mechanism of this system, which impairs the development of new applications. Herein, we have used a theoretical DFT and TD-DFT approach to (i) determine the identity of the dioxetanone species responsible for efficient chemiexcitation and (ii) identify the bioluminescent emitter and determine if light-emission occurs from the fluorescent or chemiluminescent state. Our results demonstrate that upon oxygenation of the imidazopyrazinone scaffold, a dioxetanone with a neutral amide group and a cationic guanidinopropyl group is formed. This species is efficiently chemiexcited (with no obvious charge transfer step) to the corresponding oxyluciferin with a neutral amide and cationic guanidinopropyl groups. After the "dark" chemiluminescent state, this oxyluciferin species is converted into a bright blue-emitting fluorescent state.


Assuntos
Crustáceos/química , Compostos Heterocíclicos com 1 Anel/química , Luz , Animais , Fluorescência , Humanos , Estrutura Molecular , Temperatura
13.
J Phys Chem Lett ; 10(14): 4045-4050, 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31271533

RESUMO

The phononic topological Weyl closed nodal lines, including Weyl nodal rings, nodal chains, nodal nets, nodal links, and nodal knots, have been widely studied. The phononic topological Weyl open nodal lines (PTWONLs), however, have not been well investigated so far. By analyzing the coexistence of parity inversion and time-reversal symmetries, we found that the PTWONLs can be divided into three categories, with surface states hosting different shapes and positions in the Brillouin zone (BZ). Specifically, semiconducting Rb2Sn2O3 was found to exhibit perfect PTWONLs in its phonon spectrum, which fills up one of the categories. Numerical calculations showed that the drumhead-like surface states exist on the (010) surface and six PTWONLs appear in the first BZ due to the C3 rotation symmetry in the crystal structure. Their topological nontrivial nature was confirmed by calculating the Berry phase and by the linear phononic bands around the Weyl points. These theoretical findings provide a deep understanding into the phononic Weyl-open-nodal-line physics, and a promising candidate for experimental verification.

14.
J Nat Prod ; 82(6): 1510-1517, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31150241

RESUMO

Chromatographic purification of the roots of Daphne genkwa led to 11 new guaiane-type sesquiterpenoids (1-11), named genkwanoids A-K, and six known analogues (12-17). A comprehensive set of spectroscopic methods including IR, UV, HRESIMS, and 1D/2D NMR were used to elucidate the structures and relative configurations of 1-11. The absolute configurations were determined by the optical rotation calculations and the modified Mosher's method. The possible biosynthetic pathways for 1-11 are proposed. Furthermore, the neuroprotective effects of 1-17 on H2O2-induced damage in human neuroblastoma SH-SY5Y cells were screened using an MTT assay. Compounds 9, 10, and 16 exhibited moderate neuroprotective effects, with survival rates of 79.34%, 79.94%, and 75.64% after treatment with 12.5 µM, values that were comparable to the positive control, Trolox (78.65%). Furthermore, annexin V-FITC/PI staining of cells treated with 9, 10, and 16 showed that the neuroprotective effects of these compounds may arise from inhibiting cell apoptosis.


Assuntos
Morte Celular/efeitos dos fármacos , Daphne/química , Fármacos Neuroprotetores/farmacologia , Raízes de Plantas/química , Sesquiterpenos de Guaiano/química , Sesquiterpenos/farmacologia , Humanos , Estrutura Molecular , Neuroblastoma , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/isolamento & purificação , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação
15.
J Phys Condens Matter ; 30(35): 355303, 2018 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-30027896

RESUMO

Finite-layer nanoribbon materials have long been considered as potential candidates for nanodevices with novel quantum effects. Here we constructed a series of ferromagnetic armchair silicene nanoribbons (ASiNRs) with sp 3 and sp 2-type alternating hybridizations, and found that the ASiNRs with different widths are localized in different spin-resolved electronic states. As the width parameter N is increased from 5 to 22, the ASiNR transits from indirect-gap half metallicity (HM), to indirect-gap spin semiconductor (SC), then to direct-gap SC and finally to direct-gap HM. When a temperature gradient is produced along the nanoribbons, the spin-dependent currents with the opposite flow directions are driven and a nearly perfect spin-dependent Seebeck effect (SDSE) occurs. Moreover, attributing to symmetrical spin-resolved transport channels, nearly pure thermal spin current without any accompanying charge current can be generated. In addition, for some ASiNRs with proper widths, both the thermal spin-up current and spin-down one are contributed by the electrons in energy valleys, resulting in a well-defined valley-dependent SDSE. These theoretical findings suggest that the ASiNRs with the sp 3 and sp 2-type alternating hybridizations can be outstanding candidates for future spin caloritronic devices.

16.
Chemosphere ; 197: 241-250, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29353674

RESUMO

A environment-friendly 3D inorganic heteropoly blue (HPB) Ba2Na2 [HPWV4WVI8O40]·26H2O was directly synthesized by hydrothermal method and characterized by means of ICP, IR, XPS, X-ray single crystal and X-ray powder diffraction. It was an efficient heterogeneous photo-Fenton-like catalyst to degrade anionic dye methyl orange under visible light irradiation. It removed cationic dyes methylene blue in neutral environment and rhodamine B in acidic condition via flocculation. The removal efficiency of methylene blue and rhodamine B by flocculation was more than 95%. Moreover, it could degrade methyl orange and flocculate rhodamine B at the same time. For MO and MO-RhB solutions, the degradation rates of MO in 60 min were 85.5% and 49.1%, respectively. Furthermore, the possible pathways for the production of active species in the MO degradation reaction were discussed. This is the first HPB constructed with 4e-reduced phosphotungstate, Ba and Na ions, having the properties of photo-Fenton-like catalyst and flocculant.


Assuntos
Compostos Azo/química , Recuperação e Remediação Ambiental/métodos , Peróxido de Hidrogênio/química , Ferro/química , Azul de Metileno/química , Rodaminas/química , Compostos de Tungstênio/química , Poluentes Químicos da Água/química , Catálise , Corantes/química , Luz , Compostos de Tungstênio/síntese química , Poluentes Químicos da Água/análise , Difração de Raios X
17.
Nanoscale ; 9(46): 18334-18342, 2017 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-29143060

RESUMO

The spin-dependent Seebeck effect (SDSE) is one of the core topics of spin caloritronics. In the traditional device designs of spin-dependent Seebeck rectifiers and diodes, finite spin-dependent band gaps of materials are required to realize the on-off characteristic in thermal spin currents, and nearly zero charge current should be achieved to reduce energy dissipation. Here, we propose that two ferromagnetic zigzag γ-graphyne nanoribbons (ZγGNRs) without any spin-dependent band gaps around the Fermi level can not only exhibit the SDSE, but also display rectifier and diode effects in thermal spin currents characterized by threshold temperatures, which originates from the compensation effect occurring in spin-dependent transmissions but not from the spin-splitting band gaps in materials. The metallic characteristics of ZγGNRs bring about an advantage that the gate voltage is an effective route to adjust the symmetry of spin-splitting bands to obtain pure thermal spin currents. The results provide a new mechanism to realize spin-Seebeck rectifier and diode effects in 2D materials and expand material candidates towards spin-Seebeck device applications.

18.
Phys Chem Chem Phys ; 19(39): 27132-27139, 2017 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-28967009

RESUMO

By using the first-principle calculations combined with the non-equilibrium Green's function approach, we have studied spin caloritronic properties of graphene nanoribbons (GNRs) with different edge defects. The theoretical results show that the edge-defected GNRs with sawtooth shapes can exhibit spin-dependent currents with opposite flowing directions by applying temperature gradients, indicating the occurrence of the spin-dependent Seebeck effect (SDSE). The edge defects bring about two opposite effects on the thermal spin currents: the enhancement of the symmetry of thermal spin-dependent currents, which contributes to the realization of pure thermal spin currents, and the decreasing of the spin thermoelectric conversion efficiency of the devices. It is fortunate that applying a gate voltage is an efficient route to optimize these two opposite spin thermoelectric properties towards realistic device applications. Moreover, due to the existence of spin-splitting band gaps, the edge-defected GNRs can be designed as spin-dependent Seebeck diodes and rectifiers, indicating that the edge-defected GNRs are potential candidates for room-temperature spin caloritronic devices.

19.
J Hazard Mater ; 340: 326-335, 2017 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-28728111

RESUMO

The first 3D heteropoly blue Ba2Na4[SiW4VW8VIO40]·19H2O (1) as heterogeneous Fenton-like catalyst and flocculent was hydrothermally synthesized and fully characterized by various methods 1 was an efficient Fenton-like catalyst for degradation of phenol with degradation rate of 92.1% (visible light irradiation), and 89.0% (no light) in 90min, respectively. The degradation efficiency of anionic dye methyl orange was 97.0% in 5min, when 1 was used as photo-Fenton-like catalyst under visible light. And 1 was a nice flocculent for cationic dyes methylene blue and rhodamine B, the removal rates were both above 95%. Moreover, 1 could degrade methyl orange and flocculate rhodamine B at the same time, but the degradation rate decreased from 100% to 77.5% in 60min, while the flocculation of RhB in 10min was not affected.

20.
J Asian Nat Prod Res ; 19(5): 519-527, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27649745

RESUMO

In the search for biologically active compounds from the roots of Bupleurum chinense D C., phytochemical investigation of its ethanol extract led to the isolation and identification of a new 8-O-4' neolignan glucoside, saikolignanoside A (1), along with eight known lignans (2-9). Their structures were determined on the basis of IR, UV, HRESIMS, and NMR spectroscopic analyses. The antioxidant and cytotoxic effects of isolated compounds were evaluated in vitro. The isolated compounds (IC50 > 200 µM) did not display 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Whereas compounds 1-2, 5, 7, and 9 exhibited potent 2, 2'-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging properties with IC50 values ranging from 8.34 to 15.24 µM, while compounds 3-4, 6, 8 showed moderate properties. In addition, all compounds were evaluated for cytotoxicities against A549, HepG2, U251, Bcap-37, and MCF-7 cell lines. Compounds 5 and 9 (IC50 < 51.62 µM) possessed stronger cytotoxic activities against all the tested tumor cell lines, compared with the positive control 5-Fluorouracil.


Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Bupleurum/química , Lignanas/isolamento & purificação , Lignanas/farmacologia , Antineoplásicos Fitogênicos/química , Antioxidantes/química , Benzotiazóis/química , Compostos de Bifenilo/farmacologia , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Fluoruracila/farmacologia , Humanos , Concentração Inibidora 50 , Lignanas/química , Células MCF-7 , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Picratos/farmacologia , Raízes de Plantas/química
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