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1.
Spectrochim Acta A Mol Biomol Spectrosc ; 320: 124594, 2024 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-38875928

RESUMEN

A new ratiometric fluorescent sensor (LP) based on bicarboxaminoquinoline was designed and synthesized for sequentially recognizing Zn2+ and PPi. In aqueous solution, LP exhibited the ratiometric fluorescence response towards Zn2+, along with the about 4-folds enhancement of fluorescence quantum yield. Subsequently, the LP-Zn2+ complex displayed the fluorescence recovery upon adding PPi through the displacement strategy. And the LODs of LP and its Zn2+ complex for sensing Zn2+ and PPi were found to be 15 nM and 5.5 nM, respectively. Notably, the reversibility of LP for sequentially sensing Zn2+ and PPi had been employed to construct the INHIBIT logic gate. Moreover, LP and its Zn2+ complex had been successfully utilized for the detection of Zn2+ and PPi in two real water samples and cells imaging.

2.
Ann Surg ; 2023 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-38073549

RESUMEN

OBJECTIVE: This study aimed to compare robotic pancreatoduodenectomy (RPD) with laparoscopic pancreatoduodenectomy (LPD) in operative and oncologic outcomes. BACKGROUND: Previous studies comparing RPD with LPD have only been carried out in small, single-center studies with variable quality. METHODS: Consecutive patients from nine centers in China who underwent RPD or LPD between 2015 and 2022 were included. A 1:1 propensity score matching (PSM) was used to minimize bias. RESULTS: Of the 2,255 patients, 1158 underwent RPD and 1097 underwent LPD. Following PSM, 1006 patients were enrolled in each group. The RPD group had significantly shorter operative time (270.0 vs. 305.0 minutes, P<0.001), lower intraoperative blood transfusion rate (5.9% vs. 12.0%, P<0.001), lower conversion rate (3.8% vs. 6.7%, P=0.004), and higher vascular reconstruction rate (7.9% vs. 5.6%, P=0.040) than the LPD group. There were no significant differences in estimated blood loss, postoperative length of stay, perioperative complications, and 90-day mortality. Patients who underwent vascular reconstruction had similar outcomes between the two groups, although they had significantly lower estimated blood loss (300.0 vs. 360.0 mL; P=0.021) in the RPD group. Subgroup analysis on pancreatic ductal adenocarcinoma (PDAC) found no significant differences between the two groups in median recurrence-free survival (14.3 vs. 15.3 mo, P=0.573) and overall survival (24.1 vs. 23.7 mo, P=0.710). CONCLUSIONS: In experienced hands, both RPD and LPD are safe and feasible procedures with similar surgical outcomes. RPD had the perioperative advantage over LPD especially in vascular reconstruction. For PDAC patients, RPD resulted in similar oncological and survival outcomes as LPD.

3.
RSC Adv ; 13(38): 26700-26708, 2023 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-37681035

RESUMEN

The efficient sodium phosphate (Na3PO4) solid base catalysts were prepared and applied in the production of novel biodiesel: ethylene glycol monomethyl ether monolaurate (EGMEML) by transesterification. The calcined sodium phosphate catalysts (NaP-T) were characterized using thermogravimetry analysis (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) and so on. The effects of calcination temperature of Na3PO4 and main reaction parameters such as molar ratio of ethylene glycol monomethyl ether (EGME) to methyl laurate (ML), dosage of catalyst, reaction time and temperature on the yield of EGMEML were examined. The results showed that the maximum yield of EGMEML could reach 90% under 120 °C within 4 h and 5 wt% of Na3PO4 calcined at 400°, and the catalysts displayed good stability and recovery. In addition, the kinetics of transesterification reaction was explored and the results showed that the transesterification reaction followed 1st order kinetics when a large excess of EGME was used, the activation energy (Ea) was found to be 40.2 kJ mol-1.

4.
Ying Yong Sheng Tai Xue Bao ; 33(11): 2987-2996, 2022 Oct.
Artículo en Chino | MEDLINE | ID: mdl-36384833

RESUMEN

We measured the morphological index, nutritional composition and the expression analysis of key genes during grain development of Paeonia suffruticosa cv. 'Fengdan' grown at altitudes of 100, 650 and 1010 m in Luo-yang. The aim of this study was to examine differences in grain yield traits and the transformation of soluble sugar, starch, soluble protein and fatty acid contents, as well as the related enzyme activity and differential expression of key genes in oil metabolism. The results showed that grain yield traits increased with altitudes and that the growth period of grain at the higher altitudes was longer than that at low and mid altitudes. The soluble sugar and starch in mature grains increased with altitudes, while soluble protein and crude fat did not change. During grain development, the activities of sucrose synthase (SS) and sucrose phosphate synthase (SPS) first decreased and then increased, with the lowest occurred at 90 d after flowering. The activities of pyruvate dehydrogenase (PDH), glutamic-pyruvic transaminase (GPT) and glutamic-oxalacetic transaminease (GOT) increased rapidly during 50-90 d after flowering and peaked at 90 d. The relative expression of acetyl-CoA carboxylase (ACCase) and stearoyl-ACP desaturase (SAD) peaked at 50 d after flowering, and ω-6 fatty acid desaturase 2 (FAD2) peaked at 90 d, in oil tree peony grain at different altitudes. There was a negative correlation of soluble sugar and starch with the accumulation of soluble protein and crude fat. SPS activity was positively correlated with the contents of soluble sugar and starch, and negatively correlated with the contents of soluble protein and crude fat during grain development. Activities of GPT and GOT were negatively associated with the content of soluble sugar and the content of starch, and had a highly significant positive correlation with the contents of soluble protein and crude fat. Activity of PDH was positively correlated with the content of soluble proteins and activities of GPT and GOT, and negatively correlated with the contents of soluble sugar and starch. It suggested that nutrient accumulation in the process of grain development of tree peony was transformed from sugar to crude fat and protein, and that metabolic enzymes, such as SPS, PDH, GPT and GOT, played an important role in this process. Palmitate acid, stearic acid and linoleic acid were negatively correlated with the relative increment of α-linolenic acid, indicating that fatty acid desaturation process in the grain development of tree peony was towards the direction of α-linolenic acid synthesis. The relative expression of ACCase, SAD, and FAD2 was positively correlated with the relative increment of α-linolenic acid accumulation, which played an important role in α-linolenic acid synthesis. The oil quality of tree peony grain was relatively stable at different altitudes, but grain production increased with altitude. Planting oil tree peony at mid to high altitudes could be an important strategy for the efficient use of marginal land in Luoyang.


Asunto(s)
Paeonia , Paeonia/genética , Paeonia/metabolismo , Altitud , Ácido alfa-Linolénico , Grano Comestible/metabolismo , Almidón/metabolismo , Azúcares
5.
Chin J Integr Med ; 28(9): 771-778, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35829956

RESUMEN

OBJECTIVE: To evaluate the efficacy of deep vein thrombosis (DVT) prevention among real-world surgical inpatients who received panax notoginseng saponins (PNS) combined with low-molecular-weight heparin (LMWH). METHODS: A prospective cohort study was conducted among surgical patients between January 2016 and November 2018 in Xuanwu Hospital, Capital Medical University, Beijing, China. Participants received LMWH alone or PNS combined with LMWH for preventing DVT. The primary outcome was incidence of lower extremity DVT, which was screened once a week. Participants in the LMWH group were given LMWH (enoxaparin) via hypodermic injection, 4000-8000 AxalU once daily. Participants in the exposure group received PNS (Xuesaitong oral tablets, 100 mg, 3 times daily) combined with LMWH given the same as LMWH group. RESULTS: Of the 325 patients screened for the study, 281 participants were included in the final analysis. The cohort was divided into PNS + LMWH group and LMWH group with 134 and 147 participants, respectively. There was a significant difference of DVT incidence between two groups (P=0.01), with 21 (15.7%) incident DVT in the PNS + LMWH group, and 41 (27.9%) incident DVT in the LMWH group. Compared with participants without DVT, the participants diagnosed with DVT were older and had higher D-dimer level. The multivariate logistic regression model showed a significant lower risk of incident DVT among participants in the PNS + LMWH group compared with the LMWH group (odds ratio 0.46, 95% confidence interval, 0.25-0.86). There were no significant differences in thromboelaslography values (including R, K, Angle, and MA) and differences in severe bleeding between two groups. No symptomatic pulmonary embolism occurred during the study. CONCLUSION: Combined application of PNS and LMWH can effectively reduce the incidence of DVT among surgical inpatients compared with LMWH monotherapy, without increased risk of bleeding.


Asunto(s)
Panax notoginseng , Saponinas , Trombosis de la Vena , Anticoagulantes/uso terapéutico , Hemorragia , Heparina de Bajo-Peso-Molecular/efectos adversos , Heparina de Bajo-Peso-Molecular/uso terapéutico , Humanos , Estudios Prospectivos , Saponinas/uso terapéutico , Trombosis de la Vena/inducido químicamente , Trombosis de la Vena/tratamiento farmacológico , Trombosis de la Vena/prevención & control
6.
Histol Histopathol ; 36(10): 1085-1092, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34672358

RESUMEN

BACKGROUND: Hepatocellular carcinoma (HCC) is among the most malignant tumors with high recurrence and low 5-year survival rate. Lipid metabolism is essential in tumor metastasis, although how altered lipid metabolism promotes HCC progression has not been well elucidated. Fat Storage Inducing Transmembrane Protein 2 (FITM2) is a gene involved in lipid homeostasis and cytoskeletal organization; however, its role in regulating tumor biological behavior has not been evaluated. METHODS: In this study, immunohistochemistry was performed to evaluate the expression of FITM2 in HCC. Univariate and multivariate analysis was performed to identify the prognostic factors. RNA interference wound healing and transwell experiments were performed to analyze the biological role of FITM2. Western blot analysis was performed to investigate the potential downstream signaling. RESULTS: The results revealed that FITM2 was highly expressed in the intratumoral tissues of HCC. Expression of intratumoral FITM2 was associated with microvascular invasion. FITM2 is an independent risk factor of HCC disease-free survival and overall survival. In vitro studies revealed that knockdown of FITM2 significantly inhibited the migration ability of HCC cells. FITM2 promotes HCC cell migration by regulating the expression of caveolin-1 and promoting the formation of caveolae. These results indicate that high intratumoral expression of FITM2 is associated with poor HCC prognosis, which may be applied to develop a new adjuvant therapy.


Asunto(s)
Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patología , Caveolas/patología , Movimiento Celular/genética , Proteínas de la Membrana/genética , Adulto , Anciano , Anciano de 80 o más Años , Línea Celular Tumoral , Femenino , Humanos , Inmunohistoquímica , Neoplasias Hepáticas , Masculino , Proteínas de la Membrana/biosíntesis , Persona de Mediana Edad , Invasividad Neoplásica/genética , Invasividad Neoplásica/patología , Pronóstico , Interferencia de ARN , Transducción de Señal/genética , Análisis de Supervivencia , Cicatrización de Heridas
7.
J Fluoresc ; 31(4): 907-913, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33826071

RESUMEN

A novel substituted imidazole derivative 1a with carboxyl and quinoline structure has been designed and synthesized. And our initial discovery is that this compound can effectively detect water in ethanol. And the metal in solution couldn't affect the absorption and fluorescence Spectra of 1a. With the addition of water, the energy band appears a red-shift from 330nm to 355nm in the absorption spectra. And the emission spectrum undergoes an important change in its fluorescent effect in the presence of water. Furthermore, absorption peak of 1a displays a red-shift with increasing pH from 2.31 to 10.72. All available data (absorption and emission) strongly support the possible mechanism. Due to the pronounced fluorescence changing property, the substituted imidazole derivative 1a could be utilized as fluorescent probes for detecting water in ethanol.

8.
Spectrochim Acta A Mol Biomol Spectrosc ; 241: 118658, 2020 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-32650244

RESUMEN

Research on pyrophosphate ions detection remains important because it plays crucial roles in various fields. A simple and new colorimetric sensor for pyrophosphate (PPi) based on mono-pyrenylurea ligand (L) has been designed and synthesized by a simple reaction of 1-pyrenemethylamine hydrochloride with p-nitrophenylisocyanate. In DMSO-15% H2O solution and DMSO-15% HEPES (10 mM, pH = 7.2) buffer solution, L displayed a selective colorimetric response for pyrophosphate (PPi) against other anions by changing color from colorless to yellow. This recognition process was confirmed by UV-vis spectroscopy. Also, the colorimetric properties of L are attributed to the anion-induced deprotonation of the urea subunit as demonstrated by 1H NMR titration method. Moreover, convenient test strips coated with L could be utilized to detect PPi in aqueous solution by naked-eye.

9.
Spectrochim Acta A Mol Biomol Spectrosc ; 230: 118030, 2020 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-31951867

RESUMEN

In this study, a new 4,5-quinolimide-based fluorescent sensor BNC was synthesized and characterized. BNC showed single selectivity for Cu2+via the "turn-off" fluorescence among various common metal ions. After forming a 1:1 stoichiometric complex with Cu2+, the detection limit (LOD) of BNC for Cu2+ was measured to be 0.44 µM. Subsequently, the in situ generated BNC-Cu2+ complex had been used for sensing Cys with the LOD of 1.5 µM through the displacement strategy, resulting in the revivable emission of BNC. According to the "off-on-off" fluorescence cycle of BNC generated by the alternate addition of Cu2+ and Cys, a reversible memorized device with "read-write-read-erase" behavior was constructed at the molecular level. Furthermore, the recoveries of Cu2+ in lake water with BNC were in the range of 95.0-105%. And sequential fluorescence imagings of BNC for Cu2+ and Cys were successfully applied in living yeast cells.


Asunto(s)
Técnicas Biosensibles/métodos , Cobre/análisis , Cisteína/análisis , Colorantes Fluorescentes/química , Quinolinas/química , Saccharomyces cerevisiae/metabolismo , Contaminantes Químicos del Agua/análisis , Límite de Detección , Imagen Óptica , Espectrometría de Fluorescencia
10.
Analyst ; 144(24): 7421-7431, 2019 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-31686073

RESUMEN

Carbon dots (CDs) are a developing stable, conductive, and environmentally friendly fluorescent nanomaterial with potential applications in biomedicine and sensing. In this study, CDs with up- and down-conversion photoluminescence characteristics were prepared via a one-pot hydrothermal method using coffee beans as the sole raw material. Fourier transform infrared spectra and X-ray photoelectron spectroscopy showed the presence of nitrogen and oxygen functional groups on the CDs surfaces. Transmission electron microscopy showed that the CDs were spherical with an average size of 4.6 nm. The CDs precursor and synthesis process are environmentally benign, and the resulting CDs exhibit excellent photostability, reversible fluorescence response to temperature, and good ionic-strength tolerance. Moreover, these CDs can be used as efficient fluorescence probes in selective and sensitive Fe3+ detection by a dual-readout assay. The down- and up-conversion fluorescence measurements from the CDs were in the linear range for 0-0.10 mM Fe3+ with the detection limits of 15.4 and 16.3 nM, respectively. Furthermore, the CDs were successfully applied to intracellular sensing and imaging Fe3+ ions, indicating their potential use in bioscience applications.


Asunto(s)
Café/química , Colorantes Fluorescentes/química , Hierro/análisis , Puntos Cuánticos/química , Semillas/química , Carbono/química , Carbono/efectos de la radiación , Colorantes Fluorescentes/síntesis química , Colorantes Fluorescentes/efectos de la radiación , Tecnología Química Verde/métodos , Luz , Límite de Detección , Microscopía Confocal/métodos , Microscopía Fluorescente/métodos , Puntos Cuánticos/efectos de la radiación , Solubilidad , Espectrometría de Fluorescencia/métodos , Agua/química , Levaduras
11.
Nanotechnology ; 30(45): 455601, 2019 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-31370057

RESUMEN

Optimizing of electrocatalytic hydrogen evolution reaction (HER) activity is still a gigantic challenge for improving catalysts in renewable energy field. In this research, large-scale neoteric three-dimensional (3D) hierarchical MoSe2 hollow sphere arrays with like-Pacific Plate architecture were triumphantly prepared via a facile and reliable approach. The like-Pacific Plate architecture consists of many 3D MoSe2 arrays plates with the dimensions of 10-35 µm, which is assembled by plentiful closely connecting hierarchical MoSe2 hollow spheres with the outer diameter, hierarchically secondary unit size and shell thickness of 450 nm, 25 nm and 10 nm, respectively. The products exhibited remarkable HER performance with small Tafel slope (58.5 mV dec-1), low overpotential (169.8 mV) at 10 mA cm-2, high conductivity and durable stability, which are attribute to the mechanisms (1) 3D hollow framework furnishes large specific surface area, (2) hierarchical structure generates more active sites, (3) like-Pacific Plate architecture facilitates the touch of electrolyte and catalyst, and (4) closely packed arrays expedite the migration of electron. The current work indicates that unique 3D hierarchical hollow sphere arrays with like-Pacific Plate architecture will be a potential candidate for effective electrocatalytic water splitting catalyst material with energy source application.

12.
Soft Matter ; 15(15): 3198-3207, 2019 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-30896008

RESUMEN

A novel cationic gemini surfactant (C12NDDA) with a spacer containing naphthalene and amides was successfully synthesized. The assembly of C12NDDA with ß-cyclodextrin (ß-CD) was investigated using various techniques including transmission electron microscopy, proton nuclear magnetic resonance (1H NMR), and scanning electron microscopy. Tuning the C12NDDA concentration and the C12NDDA/ß-CD molar ratio allowed the production of different assembled aggregate morphologies such as micelles, vesicles, nanowires, nanorods, and hydrogels. Investigation of the inclusion mechanisms of C12NDDA and ß-CD by 1H NMR revealed that hydrophobic interactions, hydrogen bonding, π-π stacking, and electrostatic forces play key roles in the assembly process. The antimicrobial activities of the C12NDDA/xß-CD (x = 0-4) inclusion complexes were tested against Gram-negative bacteria (Escherichia coli and Salmonella) and Gram-positive bacteria (Staphylococcus aureus and Streptococcus), and very low minimum inhibitory concentrations of 0.078-0.31 µg mL-1 were observed. Thus, this newly synthesized gemini surfactant and its inclusion complexes exhibit potential as superior broad-spectrum disinfectants for various biomedical and biotechnological applications.

13.
Biomed Pharmacother ; 103: 67-74, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29635130

RESUMEN

5-Fluorouracil (5-Fu) and cisplatin (DDP) as important therapies in treatment of human gastric cancer have been widely determined. However, the therapeutic effects are usually hampered due to drug resistance or toxicity at high concentrations for application. Avicularin (AL, quercetin-3-α-l-arabinofuranoside), a bio-active flavonol isolated from a number of plants, has been reported to display diverse pharmacological properties. In this study, we explored the hypothesis by which AL reversed 5-Fu or DDP resistance in gastric cancer and the underlying molecular mechanism. Here, in vitro, the drug-resistant cancer cells were incubated to AL or DDP alone or the combination of AL and DDP. Then, MTT, colony formation, Hoechst 33258, flow cytometry and western blot analysis were used to investigate the effects of AL in the regulation of drug-resistance gastric cancer cells. The results indicated that AL treatment markedly re-sensitizes the drug resistant cells (SGC-7901/5-Fu and SGC-7901/DDP) to cytotoxicity of 5-Fu or DDP. Molecular mechanism analysis indicated that AL and DDP combination treatment enhanced apoptosis in SGC-7901/DDP cells, accompanied with the up-regulation of cleaved Caspase-3 and PARP, as well as the activation of pro-apoptotic signals, including Bax and BOK. Significantly, down regulation of Bax or BOK expressions using Bax siRNA or BOK siRNA decreased the inhibitory role of DDP in apoptosis of SGC-7901/DDP cells pretreated with AL, demonstrating that AL-reversed DDP resistance was associated with Bax and BOK expression. In vivo, AL and DDP combination significantly reduced gastric tumor growth. Immunohistochemical analysis indicated that co-treatment of AL and DDP significantly induced apoptosis, and reduced tumor cell proliferation in tumor tissue samples. Furthermore, we also found that the Bax, BOK, cleaved Caspase-3 and PARP expression in tumor tissues were highly induced by AL and DDP co-treatment. Together, our findings may provide a novel combination therapeutic strategy in treatment of human gastric cancer.


Asunto(s)
Resistencia a Múltiples Medicamentos , Resistencia a Antineoplásicos , Flavonoides/uso terapéutico , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Neoplasias Gástricas/tratamiento farmacológico , Neoplasias Gástricas/metabolismo , Proteína X Asociada a bcl-2/metabolismo , Animales , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Cisplatino/farmacología , Cisplatino/uso terapéutico , Resistencia a Múltiples Medicamentos/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Flavonoides/química , Flavonoides/farmacología , Fluorouracilo/farmacología , Fluorouracilo/uso terapéutico , Humanos , Masculino , Ratones Desnudos , Transducción de Señal/efectos de los fármacos , Neoplasias Gástricas/patología
14.
Soft Matter ; 13(32): 5453-5462, 2017 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-28715030

RESUMEN

A novel axially chiral cationic Gemini amphiphile gelator (S1) derived from (S)-BINOL has been synthesized and characterized by 1H NMR, 13C NMR, ESI-MS and FT-IR analyses. The critical micelle concentration (CMC) of S1 was determined to be 0.21 mM in water at room temperature. A transparent hydrogel with S1 at 43 mM was obtained at room temperature and characterized using various methods including SEM, CD, fluorescence, 1H NMR, FT-IR, and XRD. The results indicate that the hydrophobic effect of long alkyl chains, π-π stacking of naphthalene rings, and intermolecular hydrogen-bonding of the amide groups of S1 should be responsible for the hydrogel formation. Moreover, an 8.5 mM aqueous solution of S1 could gel by the addition of l-arginine, whereas it failed to gel in the presence of other 15 amino acids, respectively. It is suggested that S1 could discriminate native arginine by hydrogel formation, mainly due to the electrostatic interaction and hydrogen bonding effects between S1 and l-arginine molecules.

15.
Org Biomol Chem ; 15(10): 2211-2216, 2017 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-28221392

RESUMEN

A 4,5-quinolimide derivative, BNA, bearing the amide-DPA receptor, was synthesized as a turn-on fluorescent sensor for Cd2+. Under physiological conditions, BNA could distinguish Cd2+ from Zn2+, showing turn-on fluorescence behaviour and an increased fluorescence lifetime. BNA and Cd2+ formed a 1 : 1 stoichiometric complex, and the detection limit was measured to be as low as 11 nM. Furthermore, BNA was utilized for fluorescence imaging of Cd2+ in live cells. To the best of our knowledge, it is the first 4,5-quinolimide-based sensor for the detection of metal ions.


Asunto(s)
Cadmio/análisis , Colorantes Fluorescentes/química , Viabilidad Microbiana , Quinolinas/química , Saccharomyces cerevisiae/citología , Colorantes Fluorescentes/análisis , Colorantes Fluorescentes/síntesis química , Quinolinas/análisis , Quinolinas/síntesis química
16.
Talanta ; 162: 423-427, 2017 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-27837851

RESUMEN

The addition of benzoic acid (BA) to an aqueous solution of 1-bromopyrene (1-BrPy) and γ-cyclodextrin (γ-CD) was found to form a ternary 1-BrPy/γ-CD/BA inclusion complex that exhibited strong and stable room temperature phosphorescence (RTP) without deoxygenation. The effects of several different factors on the RTP emission from the inclusion complex were subsequently investigated. A good linear relationship between the RTP intensity and the concentration of BA over the range of 0-0.70mM was identified (R2=0.9917), and the detection limit was determined to be 0.68µm. Application of the new method was successfully proved for the detection of BA in various beverages with satisfactory results.


Asunto(s)
Ácido Benzoico/análisis , Mediciones Luminiscentes/métodos , Pirenos/química , gamma-Ciclodextrinas/química , Ácido Benzoico/química , Bebidas/análisis , Reproducibilidad de los Resultados , Temperatura
17.
J Fluoresc ; 27(2): 723-728, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28004345

RESUMEN

A new ratiometric fluorescent sensor (DQO) based on N,N'-Di(quinolin-8-yl) oxalamide has been designed and synthesized for selective detection of Zn2+. The fluorescence ratio (I 536 nm/I 450 nm) of DQO was enhanced 10-fold when Zn2+ was present in a buffer aqueous solution at pH 8.66. The sensor showed linear response toward Zn2+ in the concentration range 0-15 µM, and the detection limit was calculated to be 2.4 µM. A Job's plot implied the formation of a DQO/Zn2+ complex with 1:1 stoichiometry, and the apparent association constant of DQO/Zn2+ complex was computed to be 1.5 × 104 M-1.

18.
Springerplus ; 4: 686, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26576329

RESUMEN

Diethylene glycol monomethyl ether monolaurate (DGMEML) was synthesized via the reaction of diethylene glycol monomethyl ether (DGME) with methyl laurate (ML) by a new solid base catalyst of KF/CaO/AC, which was prepared by impregnation method using active carbon as carrier. The catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), nitrogen physisorption-desorption and Hammett indicator methods; the effect of the mole ratio of KF to CaO, DGME to ML molar ratio, amount of catalyst, reaction time and temperature on the yield of DGMEML were studied; and the relationship between the structure of the catalyst and the yield of DGMEML was investigated. The formed KCaF3 and K2O were acting as the main active components in the catalytic transesterification; the highest yield of 96.3 % was obtained as KF-to-CaO molar ratio of 2.0, DGME to ML molar ratio of 4.0, catalyst amount of 5 wt%, and reaction time of 30 min at 75 °C; and the catalyst displayed good stability in the transesterification.

19.
J Fluoresc ; 25(2): 441-9, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25721992

RESUMEN

Three fluorescent sensors which were composed of a phendiol (o-, m-, p-isomers) and two carboxamidoquinolines have been synthesized and characterized. Research on the Zn(2+)-sensing properties of the three sensors was carried out, and the results showed a significant difference in the recognition performance for Zn(2+). The fluorescence intensity (I(510 nm)) of ortho isomeric sensor binding to Zn(2+) was enhanced 23-fold, the meta 15-fold, the para 8-fold. As the distance between two carboxamidoquinolines became longer, the fluorescence enhancement decreased. In addition, the selectivity of sensors got poor and the detection limit became higher with rising the distance between two receptors.


Asunto(s)
Técnicas de Química Analítica/instrumentación , Quinolinas/química , Zinc/análisis , Zinc/química , Absorción Fisicoquímica , Isomerismo , Límite de Detección , Fenol/química , Quinolinas/síntesis química , Espectrometría de Fluorescencia
20.
J Nanosci Nanotechnol ; 14(6): 4692-9, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24738448

RESUMEN

The V-based complex oxides were found to exhibit good catalytic reactivity for the selective oxidation of benzene to phenol. In order to understand the effect of the catalyst on the reaction, a series of Ag/VO(x)-TiO2 catalysts with different Ag loadings were prepared. Data from the X-ray diffraction (XRD), N2-adsorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS) showed the formation of complex oxides with phases of silver and vanadates, and the increased redox ability of vanadium species. The results from H2-TPR revealed that the addition of Ag promoted the reduction of vanadium species in the complex catalysts. The presence of Ag and Ag+ ions at the catalyst surface were proved independently by XPS measurements. The Ag and Ag+ ions also effectively strengthened the thermostability of the Ag/VO(x)-TiO2 catalyst, and the Ag species also made a strong contribution to the monodispersion of vanadium on the surface of the TiO2 carrier. The reactivity for the selective oxidation of benzene was evaluated by using a liquid-phase reaction unit, and was correlated with the surface redox property of the catalysts.


Asunto(s)
Benceno/química , Nanopartículas del Metal/química , Nanopartículas del Metal/ultraestructura , Nanoporos/ultraestructura , Plata/química , Titanio/química , Compuestos de Vanadio/química , Catálisis , Hidroxilación , Sustancias Macromoleculares/química , Ensayo de Materiales , Oxigenasas de Función Mixta/química , Conformación Molecular , Tamaño de la Partícula , Porosidad , Propiedades de Superficie
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