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1.
Chin J Integr Med ; 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38990478

RESUMO

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice. It has a high prevalence and poor prognosis. The application of antiarrhythmic drugs and even surgery cannot completely treat the disease, and there are many sequelae. AF can be classified into the category of "palpitation" in Chinese medicine according to its symptoms. Acupuncture has a significant effect on AF. The authors find that an important mechanism of acupuncture in AF treatment is to regulate the cardiac vagus nerve. Therefore, this article intends to review the distribution and function of vagus nerve in the heart, the application and the regulatroy effect for the treatment of AF.

2.
Materials (Basel) ; 17(8)2024 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-38673161

RESUMO

In recent years, due to the rapid growth of mankind's demand for energy, harmful gases (SOx) produced by the combustion of sulfur-containing compounds in fuel oil have caused serious problems to the ecological environment and human health. Therefore, in order to solve this hidden danger from the source, countries around the world have created increasingly strict standards for the sulfur content in fuel. Adsorption desulfurization technology has attracted wide attention due to its advantages of energy saving and low operating cost. This paper reviewed the latest research progress on various porous adsorption materials. The future challenges and research directions of adsorption materials to meet the needs of clean fuels are proposed.

3.
Int J Gen Med ; 17: 387-399, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38333018

RESUMO

Objective: This study was to investigate the mechanism of action and clinical efficacy of fire-needle therapy in improving neurological function in patients with acute cerebral infarction (identified as a wind-phlegm-blood stasis syndrome in traditional Chinese medicine). Methods: We included patients diagnosed with acute cerebral infarction (wind-phlegm-blood stasis syndrome) admitted to the Encephalopathy and Acupuncture Center of the Second Affiliated Hospital of Tianjin University of Chinese Medicine. We randomly allocated them into the treatment and control groups, with 45 cases in each group. Acupuncture treatments that focused on regulating the mind and dredging the collaterals were used in the control group, while the treatment group additionally received fire-needle therapy. Our indicators included the National Institutes of Health Stroke Scale (NIHSS) scores, the Fugl-Meyer Assessment (FMA) scale, peripheral blood tumor necrosis factor-α (TNF-α), interleukin-17 (IL-17), hypersensitivity C-reactive protein (hs-CRP), and intestinal metabolites short-chain fatty acids (SCFAs). We measured these indicators before treatment and 14 days after treatment. Results: The post-treatment NIHSS scores of the two groups were significantly reduced (P < 0.05), and the treatment group showed a more significant decline in the score when compared to the control group (P < 0.05). The treatment group showing significant improvement in the domains of reflex activity, mobility, cooperative movement, and finger movement (P < 0.05). Both groups showed a significant decrease in the IL-17 and hs-CRP levels (P < 0.05), with the treatment group demonstrating a significant declining trend when compared to the control group (P < 0.05). The levels of acetic acid, propionic acid, butyric acid, and valeric acid all increased significantly in the two groups (P < 0.05), with acetic acid and butyric acid increasing significantly in the treatment group when compared to the control group (P < 0.05). Clinical efficacy rate: 78.6% of patients in the treatment group had an excellent rate, whereas it was 30.0% in the control group, and the difference was statistically significant (P < 0.001). Conclusion: Fire-needle therapy was effective in upregulating the SCFA content in patients with acute cerebral infarction (wind-phlegm-blood stasis syndrome), inhibiting the level of the inflammatory response, and improving the recovery of neurological functions. Clinical registration number: Registration website link: https://www.chictr.org.cn. Registration date: 2022/9/27. Registration number: ChiCTR2200064122.

4.
Materials (Basel) ; 16(23)2023 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-38068053

RESUMO

The use of fossil fuels leads to significant CO2 emissions, thus highlighting the importance for investigating the utilization of CO2 for generating high-value chemical products toward achieving the dual-carbon goal. CO2 can be efficiently used in synthesizing valuable organic compounds through C-C, C-O, C-H, and C-N bond construction, with reduction technologies effectively converting CO2 to organic carbon sources. Therefore, the research in developing environmentally friendly catalysts for efficient and renewable CO2 conversion holds great importance. New materials for catalytic conversion include zeolites, activated carbon, graphene, metal-organic frameworks (MOFs), covalent organic frameworks (COFs), ionic liquids, semiconducting photocatalysts, single-atom catalysts (SACs), and dendritic mesoporous silica nanoparticles (DMSNs). The proper research and use of these materials can aid in the quest to reduce carbon emissions and mitigate climate change. This Review focuses on the utilization of single-atom catalysts (SACs), ionic liquids (ILs), dendritic mesoporous silica nanoparticles (DMSNs), and carbene-metal catalytic systems in CO2 conversion. The potential for new materials in catalyzing the conversion of CO2 is examined by analyzing various common chemical carbon sequestration methods, ultimately providing possible research directions for effective solutions to climate and environmental pollution problems. On the basis of the high reaction rate and high treatment efficiency of the catalyst for the catalytic conversion of CO2, the Review focuses on the simpler and more economical synthesis method of the catalyst itself and the wider application prospects.

5.
Materials (Basel) ; 16(20)2023 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-37895797

RESUMO

With their rich surface chemistry, high electrical conductivity, variable bandgap, and thermal stability, 2D materials have been developed for effective electrochemical energy conversion systems over the past decade. Due to the diversity brought about by the use of transition metals and C/N pairings, the 2D material MXene has found excellent applications in many fields. Among the various applications, many breakthroughs have been made in electrocatalytic applications. Nevertheless, related studies on topics such as the factors affecting the material properties and safer and greener preparation methods have not been reported in detail. Therefore, in this paper, we review the relevant preparation methods of MXene and the safer, more environmentally friendly preparation techniques in detail, and summarize the progress of research on MXene-based materials as highly efficient electrocatalysts in the electrocatalytic field of hydrogen precipitation reaction, nitrogen reduction reaction, oxygen precipitation reaction, oxygen reduction reaction, and carbon dioxide reduction reaction. We also discuss the technology related to MXene materials for hydrogen storage. The main challenges and opportunities for MXene-based materials, which constitute a platform for next-generation electrocatalysis in basic research and practical applications, are highlighted. This paper aims to promote the further development of MXenes and related materials for electrocatalytic applications.

6.
J Hazard Mater ; 458: 131977, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37393824

RESUMO

By constructing nanofluid system, trace functionalized nanoparticles can significantly enhance the absorption performance of basic liquid. In this work, amino functionalized carbon nanotubes (ACNTs) and carbon nanotubes (CNTs) were introduced into alkaline deep eutectic solvents to build nanofluid systems and used for the dynamic absorption of H2S. The experiment results showed that the introduction of nanoparticles can significantly enhance the H2S removal performance of original liquid. When performing H2S removal experiments, the optimal mass concentrations of ACNTs versus CNTs were 0.05 % and 0.01 %, respectively. The characterization showed that the surface morphology and structure of the nanoparticles unchanged significantly during the absorption-regeneration process. A double mixed gradientless gas-liquid reactor was used to explore the gas-liquid absorption kinetics characteristics of the nanofluid system. It was found that the gas-liquid mass transfer rate increased significantly after the addition of nanoparticles. The highest total mass transfer coefficient of the nanofluid system of ACNTs was increased to more than 400 % of the value before the addition of nanoparticles. The analysis showed that the shuttle effect and hydrodynamic effect of nanoparticles play important role in the process of enhancing gas-liquid absorption, and the amino functionalization enhanced the shuttle effect of nanoparticles significantly.

7.
Molecules ; 28(6)2023 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-36985510

RESUMO

Amphiphilic hybrid catalysts were prepared by modifying [SMo12O40]2- with tetrabutylammonium bromide (TBAB), 1-butyl-3-methylimidazole bromide (BMIMBr) and octadecyl trimethyl ammonium bromide (ODAB), respectively. The prepared catalysts were characterized by IR, XRD, SEM, TG and XPS. The desulfurization performance of the catalysts was investigated in model oil and actual diesel using hydrogen peroxide (H2O2) as an oxidant and acetonitrile as an extractant. All catalysts exhibited favorable activity for removing sulfur compounds at room temperature. Dibenzothiophene (DBT) can be nearly completely removed using SMo12O402--organic catalysts within a short reaction time. For different sulfur compounds, the [TBA]2SMo12O40 catalyst showed a better removal effect than the [BMIM]2SMo12O40 and [ODA]2SMo12O40 catalyst. The [TBA]2SMo12O40 dissolved in extraction solvent could be reused up to five times in an oxidative desulfurization (ODS) cycle with no significant loss of activity. The [BMIM]2SMo12O40 performed as a heterogeneous catalyst able to be recycled from the ODS system and maintained excellent catalytic activity. The catalysts showed a positive desulfurization effect in real diesel treatment. Finally, we described the ODS desulfurization mechanism of DBT using SMo12O402--organic hybrid catalysts. The amphiphilic hybrid catalyst cation captures DBT, while SMo12O402- reacts with the oxidant H2O2 to produce peroxy-active species. DBT can be oxidized to its sulfone by the action of peroxy-active species to achieve ODS desulfurization.

8.
Materials (Basel) ; 16(6)2023 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-36984056

RESUMO

In this article, we reported a novel setup treatment using nitric acid vapor to treat g-C3N4 (CN). By treatment with nitric acid vapour, the basic structure of the CN has not been destroyed. These adoptive treatments enhanced the photocatalytic performance of CN and were reflected in the elimination of rhodamine B (RhB) as well as tetracycline hydrochloride (TC). In comparison to CN, CN-6 demonstrated the highest photocatalytic yield for the breakdown of RhB (99%, in 20 min). Moreover, the excellent reuse of CN-6 for breaking down RhB was also demonstrated. This clearly demonstrated that treatment with nitric acid vapor promoted a blue shift, positively extended its valence band position, and increased the oxidizability of the holes. This also caused CN to disperse better into the aqueous phase, introducing more oxygen-containing functional groups. Thus, treatment with nitric acid vapor has the potential to be applied to delaminate the CN in order to enhance photocatalytic activity.

9.
Ultrasonics ; 124: 106730, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35313187

RESUMO

The T-shaped R-zone component widely exists in aerospace and satellite communication area, such as supporting structure under the wing skin and the mechanical supporting frame of the satellite large load-bearing high-precision test platform, which seriously affects the performance and the safety of the aircraft and the satellite. In this paper, the overall process of ultrasonics methodology of T-shaped R-zone components is proposed, systematically investigated and experimentally verified. The detection of the defect and the stress is respectively realized based on the synthetic aperture total focusing method and the Mohr's stress circle theory with the aid of the linear phased array probe and the longitudinal wave along the stress propagation direction. The theoretical simulations and the experimental measurements both demonstrate the effectiveness of the proposed methodology. The dimensional and the positioning errors are respectively around 0.67 mm and 1.69 mm for the 1 mm × 4 mm crack defect existed in the T-shaped R-zone component. The detecting error of the stress is less than 17.91 MPa in the entire inner of the T-shaped R-zone component, which is applied a pressure in the range of 0-400 MPa.


Assuntos
Ultrassom , Animais
10.
Plant Cell Rep ; 41(4): 1087-1101, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35150305

RESUMO

KEY MESSAGE: Glycinebetaine alleviates chilling stress by protecting photosystems I and II in BADH-transgenic and GB-treated tomato plants, which can be an effective strategy for improving crop chilling tolerance. Tomato (Solanum lycopersicum) is one of the most cultivated vegetables in the world, but is highly susceptible to chilling stress and does not naturally accumulate glycinebetaine (GB), one of the most effective stress protectants. The protective mechanisms of GB on photosystem I (PSI) and photosystem II (PSII) against chilling stress, however, remain poorly understood. Here, we address this problem through exogenous GB application and generation of transgenic tomatoes (Moneymaker) with a gene encoding betaine aldehyde dehydrogenase (BADH), which is the key enzyme in the synthesis of GB, from spinach. Our results demonstrated that GB can protect chloroplast ultramicrostructure, alleviate PSII photoinhibition and maintain PSII stability under chilling stress. More importantly, GB increased the electron transfer between QA and QB and the redox potential of QB and maintained a high rate of cyclic electron flow around PSI, contributing to reduced production of reactive oxygen species, thereby mitigating PSI photodamage under chilling stress. Our results highlight the novel roles of GB in enhancing chilling tolerance via the protection of PSI and PSII in BADH transgenic and GB-treated tomato plants under chilling stress. Thus, introducing GB-biosynthetic pathway into tomato and exogenous GB application are effective strategies for improving chilling tolerance.


Assuntos
Solanum lycopersicum , Betaína/metabolismo , Betaína/farmacologia , Betaína-Aldeído Desidrogenase/genética , Elétrons , Solanum lycopersicum/metabolismo , Fotossíntese , Complexo de Proteína do Fotossistema I/genética , Complexo de Proteína do Fotossistema II/metabolismo , Plantas Geneticamente Modificadas/metabolismo
11.
Biosens Bioelectron ; 151: 111966, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31999576

RESUMO

Known for their capabilities in automated fluid manipulation, microfluidic devices integrated with pneumatic valves are broadly used for researches in life science and clinical practice. The application is, however, hindered by the high cost and overly complex fabrication procedure. Here, we present an approach for fabricating molds of active fluidic devices using a benchtop 3D printer and a simple 2-step protocol (i.e. 3D printing and polishing). The entire workflow can be completed within 6 h, costing less than US$ 5 to produce all necessary templates for PDMS replica molding, which have smooth surface and round-shaped pneumatic valve structures. Moreover, 3D printing can create unique bespoke on-off objects of a wide range of dimensions. The millimeter- and centimeter-sized features allow examination of large-scale biological samples. Our results demonstrate that the 3D-printed active fluidic device has valve control capacities on par with those made by photolithography. Controlled nutrients and ligands delivery by on-off active valves allows generation of dynamic signals mimicking the ever-changing environmental stimuli, and combinatorial/sequential drug inputs for therapeutic screening on liver tumor spheroid. We believe that the proposed methodology can pave the way for integration of active fluidic systems in research labs, clinical settings and even household appliances for a broad range of application.


Assuntos
Técnicas Biossensoriais , Dispositivos Lab-On-A-Chip , Neoplasias Hepáticas/diagnóstico , Impressão Tridimensional , Humanos , Neoplasias Hepáticas/patologia , Esferoides Celulares/patologia
12.
Commun Chem ; 3(1): 152, 2020 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-36703331

RESUMO

Overprediction is a major limitation of current crystal structure prediction (CSP) methods. It is difficult to determine whether computer-predicted polymorphic structures are artefacts of the calculation model or are polymorphs that have not yet been found. Here, we reported the well-known vitamin nicotinamide (NIC) to be a highly polymorphic compound with nine solved single-crystal structures determined by performing melt crystallization. A CSP calculation successfully identifies all six Z' = 1 and 2 experimental structures, five of which defy 66 years of attempts at being explored using solution crystallization. Our study demonstrates that when combined with our strategy for cultivating single crystals from melt microdroplets, melt crystallization has turned out to be an efficient tool for exploring polymorphic landscapes to better understand polymorphic crystallization and to more effectively test the accuracy of theoretical predictions, especially in regions inaccessible by solution crystallization.

13.
Bioorg Med Chem ; 27(10): 2112-2121, 2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-30981607

RESUMO

A series of bi-functional 7-hydroxycoumarin platinum(IV) complexes were synthesized, characterized, and evaluated for antitumor activities. The 7-hydroxycoumarin platinum(IV) complexes display moderate to effective antitumor activities toward the tested cell lines and show much potential in overcoming drug resistance of platinum(II) drugs. In reducing microenvironment, the title compounds could be reduced to platinum(II) complex accompanied with two equivalents of coumarin units. By a unique mechanism, the 7-hydroxycoumarin platinum(IV) complex attacks DNA via the released platinum(II) compound, meanwhile it also inhibits the activities of cyclooxygenase by coumarin fragment. This action mechanism might be of much benefit for reducing tumor-related inflammation in the progress of inhibiting tumor proliferation and overcoming cisplatin resistance. The incorporation of 7-hydroxycoumarin leads to significantly enhanced platinum accumulation in both whole tumor cells and DNA. The HSA interaction investigation reveals that the tested coumarin platinum(IV) compound could effectively combine with HSA via van der Waals force and hydrogen bond.


Assuntos
Antineoplásicos/síntese química , Complexos de Coordenação/síntese química , Platina/química , Umbeliferonas/química , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/metabolismo , Complexos de Coordenação/farmacologia , Ciclo-Oxigenase 2/química , Ciclo-Oxigenase 2/metabolismo , Dano ao DNA/efeitos dos fármacos , Humanos , Ligação Proteica , Albumina Sérica/química , Albumina Sérica/metabolismo
14.
J Inorg Biochem ; 194: 34-43, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30826588

RESUMO

A series of new 4-hydroxycoumarin platinum(IV) complexes were designed, synthesized and evaluated as antitumor agents. All the title compounds display moderate to effective antitumor activities toward the tested cell lines and two prominent compounds were screened out with activities comparable to cisplatin and oxaliplatin. The mechanism investigation demonstrates that the platinum(IV) compounds could be reduced to bivalence and exert significant genotoxicity to tumor cells. Meanwhile the coumarin moiety endows the title compounds with cyclooxygenase inhibitory competence which might favour the reduction of tumor-related inflammation and further influence tumor proliferation. The coumarin platinum(IV) complex could effectively induce apoptosis of SKOV-3 cells through up-regulating the expression of caspase3 and caspase9. Furthermore, the conversion of platinum(II) drugs to platinum(IV) form via the conjunction with 4-hydroxycoumarin enhances the drug uptake in whole cells and DNA simultaneously. Moreover, the 4-hydroxycoumarin platinum(IV) complex could combine with human serum albumin via van der Waals force and hydrogen bond, which would influence their transport and bioactivities in vivo.


Assuntos
4-Hidroxicumarinas/farmacologia , Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , 4-Hidroxicumarinas/síntese química , 4-Hidroxicumarinas/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/metabolismo , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Complexos de Coordenação/síntese química , Complexos de Coordenação/metabolismo , Inibidores de Ciclo-Oxigenase 2/síntese química , Inibidores de Ciclo-Oxigenase 2/metabolismo , Inibidores de Ciclo-Oxigenase 2/farmacologia , DNA/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Desenho de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Células HEK293 , Humanos , Platina/química , Albumina Sérica Humana/metabolismo
15.
ACS Biomater Sci Eng ; 5(3): 1635-1644, 2019 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-33405636

RESUMO

Mitochondria-targeting nanotherapy receives great attention these days for its capacity in disrupting mitochondria function and inducing tumor cell apoptosis through external magnetic and optical stimulations. However, the effect is significantly diminished when applied to animal models. The key factors include environmental complexity in vivo and intrinsic protective features of tumor tissues. To address these obstacles and reduce expenses on drug screening, we herein introduce a methodology for producing millimeter-sized spheroids with structural and functional characteristics of tumor tissues in vivo. The necessity of spheroid as a liver tumor model is demonstrated by comparing the effect of TPP-SPIONs (triphenylphosphonium cation-superparamagnetic iron oxide nanoparticles) on monolayer-cultured HepG2 cells and spheroids. Our study reveals that large-scale spheroid, in contrast to monolayer cells, reflects more in vivo tumor characters and is less responsive to TPP-SPIONs during magnetic hyperthermia treatment.

16.
Eur J Pharm Sci ; 124: 127-136, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30153524

RESUMO

Naphthalimide platinum(IV) antitumor complexes with potential dual DNA damage mechanism were designed, synthesized and evaluated for antitumor activities. The incorporation of DNA targeted naphthalimide group to the platinum(IV) system exerts much positive impacts on their antitumor efficacy. The mechanism research reveals that the title compounds could interact with dsDNA in platinum(IV) form via the naphthalimide group and cause DNA lesion. The further reduction would release platinum(II) complexes and naphthalimide acids which would induce remarkable secondary damage to DNA. Furthermore, the naphthalimide platinum(IV) compounds could combine with human serum albumin via electrostatic force, which are favourable for their storage and transport in blood. Moreover, the title compounds exhibit higher accumulation in tumor cells, and exert lower toxic and higher safe properties than oxaliplatin in vivo.


Assuntos
Antineoplásicos/farmacologia , Naftalimidas/farmacologia , Compostos Organoplatínicos/farmacologia , Linhagem Celular Tumoral , Dano ao DNA , Humanos
17.
Int J Nanomedicine ; 12: 6909-6921, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29075110

RESUMO

PURPOSE: Breast cancer stem cells (CSCs) are responsible for the initiation, recurrence, and metastasis of breast cancer. Sufficient evidence has established that breast cancer cells can spontaneously turn into breast CSCs. Thus, it is essential to simultaneously target breast CSCs and cancer cells to maximize the efficacy of breast cancer therapy. HER2 has been found to be overexpressed in both breast CSCs and cancer cells. We developed salinomycin-loaded polymer-lipid hybrid anti-HER2 nanoparticles (Sali-NP-HER2) to target both HER2-positive breast CSCs and cancer cells. METHODS: The antitumor activity of Sali-NP-HER2 constructed by conjugating anti-HER2 antibodies to polymer-lipid salinomycin nanoparticles was evaluated in vitro and in vivo. RESULTS: Sali-NP-HER2 efficiently bound to HER2-positive breast CSCs and cancer cells, resulting in enhanced cytotoxic effects compared with non-targeted nanoparticles or salinomycin. In mice bearing breast cancer xenografts, administration of Sali-NP-HER2 exhibited superior efficacy in inhibiting tumor growth. Sali-NP-HER2 reduced the breast tumorsphere formation rate and the proportion of breast CSCs more effectively than non-targeted nanoparticles or salinomycin alone. CONCLUSION: Sali-NP-HER2 represents a promising approach in treating HER2-positive breast cancer by targeting both breast CSCs and cancer cells.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Sistemas de Liberação de Medicamentos/métodos , Nanopartículas/administração & dosagem , Piranos/administração & dosagem , Receptor ErbB-2/metabolismo , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/farmacologia , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Feminino , Humanos , Lipídeos/química , Camundongos , Nanopartículas/química , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/patologia , Polímeros/química , Receptor ErbB-2/antagonistas & inibidores , Receptor ErbB-2/imunologia , Ensaios Antitumorais Modelo de Xenoenxerto
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 173: 584-592, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-27776313

RESUMO

Combination therapy with more than one therapeutic agent can improve therapeutic efficiency and decrease drug resistance. In this study, the interactions of human serum albumin (HSA) with individual or combined anticancer drugs, (-)-epigallocatechin-3-gallate (EGCG) and 5-fluorouracil (FU), were investigated by fluorescence and circular dichroism (CD) spectroscopy. The results demonstrated that the interaction of EGCG or FU with HSA is a process of static quenching and EGCG formed a more stable complex. The competitive experiments of site markers suggested that both anti-carcinogens mainly bound to site I (subdomain IIA). The interaction forces which play important roles in the binding process were discussed based on enthalpy and entropy changes. Moreover, the competition binding model for a ternary system was proposed so as to precisely calculate the binding parameters. The results demonstrated that one drug decreased the binding affinity of another drug with HSA, resulting in the increasing free drug concentration at the action sites. CD studies indicated that there was an alteration in HSA secondary structure due to the binding of EGCG and FU. It can be concluded that the combination of EGCG with FU may enhance anticancer efficacy. This finding may provide a theoretical basis for clinical treatments.


Assuntos
Catequina/análogos & derivados , Fluoruracila/metabolismo , Albumina Sérica Humana/química , Albumina Sérica Humana/metabolismo , Antimetabólitos Antineoplásicos/metabolismo , Antineoplásicos Fitogênicos/metabolismo , Sítios de Ligação , Ligação Competitiva , Catequina/metabolismo , Dicroísmo Circular , Sinergismo Farmacológico , Humanos , Ibuprofeno/metabolismo , Estrutura Secundária de Proteína , Espectrometria de Fluorescência , Termodinâmica , Varfarina/metabolismo
19.
Nanoscale Res Lett ; 11(1): 126, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26951126

RESUMO

In this report, a novel photocatalyst based on Bi2WO6/Ag2S heterostructures was prepared by a 3-mercaptopropionic acid (MPA)-assisted route at room temperature. Compared to bare Bi2WO6 and Ag2S nanoparticles, the as-formed Bi2WO6/Ag2S heterostructures exhibit enhanced photocatalytic activity for the degradation of rhodamine B (Rh B) under visible-light irradiation. This kind of enhancement in the photocatalytic activity is considered to be the synergistic effects of both the effective electron-hole separation and expansion of the light-absorption range. The pH of the solution is of vital importance to the photocatalytic activity of the as-formed Bi2WO6/Ag2S heterostructures. Under low pH value, the photosensitization process is suppressed, while under higher pH value, the photosensitization process is favored. The mechanism of the photocatalytic process was proposed by the active-species-trapping experiments, indicating that the photogenerated holes (h(+)) play a crucial role in the degradation of Rh B under visible light. The enhanced photocatalytic performance of this heterostructure makes it a promising material for the treatment of dye-containing wastewater.

20.
Food Chem ; 196: 148-54, 2016 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-26593476

RESUMO

The stability and bioavailability of catechins, a kind of tea polyphenols with health benefit, could be improved by complexing with cyclodextrins. The aim of this study was to investigate the complexation of two geometrical isomers, (+)-catechin and (-)-epicatechin, with hydroxypropyl-ß-cyclodextrin (HP-ß-CD) in tris-HCl buffer solutions at pH 6.8-8.0 using isothermal titration calorimetry, fluorescence and proton nuclear magnetic resonance spectroscopy. Experimental results showed that these inclusion interactions are primarily enthalpy-driven processes. The complexation constant (KC) of EC+HP-ß-CD complex was less than that of CA+HP-ß-CD at the same temperature and pH value. Temperature and pH studies showed that the KC value decreased with the rise of temperature and pH. Stability study indicated that HP-ß-CD showed a stronger protection effect on CA than that on EC. The different inclusion modes between CA and EC were discussed in terms of the discrepancy in their molecular structures.


Assuntos
Catequina/química , Espectrometria de Fluorescência/métodos , beta-Ciclodextrinas/química , 2-Hidroxipropil-beta-Ciclodextrina , Estrutura Molecular , Temperatura
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