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1.
J Org Chem ; 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31380639

RESUMO

The facile synthesis of a series of benzodithiophene (BDT)- and indacenodithiophene (IDT)-based A-D-A oligomers with different end groups is reported, and their properties are studied by optical spectroscopy, electrochemistry, and density functional theory calculations. The permutation of central and terminal units tunes the optoelectronic properties and photovoltaic device characteristics in a predictable way, aiding in the rational design of small molecule semiconducting materials. Among the three rhodanine-derived terminal groups, N-alkylthiazolonethione revealed the strongest electron-withdrawing character, resulting in the lowest band gap, the highest stability, and the best photovoltaic device performance. The crystallographic analysis of two IDT derivatives yielded a highly unusual three-dimensional packing of the conjugated backbone, which is likely responsible for the remarkable photovoltaic performance of such A-D-A semiconductors.

2.
Artigo em Inglês | MEDLINE | ID: mdl-31359568

RESUMO

Designing structural order in electronically active organic solids remains a great challenge in the field of materials chemistry. Now, 2D poly(arylene vinylene)s prepared as highly crystalline covalent organic frameworks (COFs) by base-catalyzed aldol condensation of trimethyltriazine with aromatic dialdehydes are reported. The synthesized polymers are highly emissive (quantum yield of up to 50 %), as commonly observed in their 1D analogues poly(phenylene vinylene)s. The inherent well-defined porosity (surface area ca. 1000 m2 g-1 , pore diameter ca. 11 Šfor the terephthaldehyde derived COF-1) and 2D structure of these COFs also present a new set of properties and are likely responsible for the emission color, which is sensitive to the environment. COF-1 is highly hydrophilic and reveals a dramatic macroscopic structural reorganization that has not been previously observed in framework materials.

3.
PLoS One ; 13(4): e0192324, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29668672

RESUMO

H2O2 was adopted to oxidize NO in simulated flue gas at 100-500°C. The effects of the H2O2 evaporation conditions, gas temperature, initial NO concentration, H2O2 concentration, and H2O2:NO molar ratio on the oxidation efficiency of NO were investigated. The reason for the narrow NO oxidation temperature range near 500°C was determined. The NO oxidation products were analyzed. The removal of NOx using NaOH solution at a moderate oxidation ratio was studied. It was proven that rapid evaporation of the H2O2 solution was critical to increase the NO oxidation efficiency and broaden the oxidation temperature range. the NO oxidation efficiency was above 50% at 300-500°C by contacting the outlet of the syringe needle and the stainless-steel gas pipe together to spread H2O2 solution into a thin film on the surface of the stainless-steel gas pipe, which greatly accelerated the evaporation of H2O2. The NO oxidation efficiency and the NO oxidation rate increased with increasing initial NO concentration. This method was more effective for the oxidation of NO at high concentrations. H2O2 solution with a concentration higher than 15% was more efficient in oxidizing NO. High temperatures decreased the influence of the H2O2 concentration on the NO oxidation efficiency. The oxidation efficiency of NO increased with an increase in the H2O2:NO molar ratio, but the ratio of H2O2 to oxidized NO decreased. Over 80% of the NO oxidation product was NO2, which indicated that the oxidation ratio of NO did not need to be very high. An 86.7% NO removal efficiency was obtained at an oxidation ratio of only 53.8% when combined with alkali absorption.


Assuntos
Peróxido de Hidrogênio/química , Óxido Nítrico/química , Poluentes Atmosféricos/química , Oxirredução , Hidróxido de Sódio/química , Temperatura Ambiente
5.
Nat Protoc ; 10(10): 1459-73, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26334866

RESUMO

The mouse fetal metatarsal provides a unique tool for studying angiogenesis. In comparison with other commonly used in vitro or ex vivo angiogenesis assays, vessel outgrowth from mouse fetal metatarsals is more representative of sprouting angiogensis in vivo. It allows the analysis of blood vessel growth, and the mechanisms underpinning this process, in a multicellular microenvironment that drives the formation of a robust and complex vascular network in the absence of exogenous growth factors. By labeling different constituents of the vascular structure, it is possible to perform 3D rendering of the spatial interplay between different cellular components and to carry out quantitative analysis of vessel outgrowth. High-resolution imaging permits the visualization of fine structural and cellular details. As the assay involves the use of fetal tissues, it is possible to follow new blood vessel formation in genetically modified mice that are perinatally lethal. The entire process takes 9-13 d. A detailed description of how to set up and perform the assay is described here.


Assuntos
Técnicas de Cultura/métodos , Ossos do Metatarso/irrigação sanguínea , Neovascularização Patológica/patologia , Animais , Modelos Animais de Doenças , Feminino , Feto , Imunofluorescência , Ossos do Metatarso/patologia , Camundongos , Microvasos/patologia , Neovascularização Patológica/genética , Coloração e Rotulagem
6.
Org Lett ; 17(13): 3342-5, 2015 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-26102233

RESUMO

1-Amino-2,2-difluorocyclopropane-1-carboxylic acid (DFACC) is of interest in the study of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase due to the increased reactivity of its cyclopropyl functionality. It is shown that DFACC is unstable under near-physiological conditions where it primarily decomposes via specific-base catalysis to 3-fluoro-2-oxobut-3-enoic acid with a rate constant of 0.18 ± 0.01 min(-1). Upon incubation with ACC deaminase, DFACC is found to be a slow-dissociating inhibitor of ACC deaminase with submicromolar affinity.


Assuntos
Aminoácidos Cíclicos/química , Carbono-Carbono Liases/antagonistas & inibidores , Ácidos Carboxílicos/química , Catálise , Estrutura Molecular
7.
Zhen Ci Yan Jiu ; 40(1): 56-60, 2015 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-25845222

RESUMO

OBJECTIVE: To investigate short- and long-term benefits and safety of acupoint injection of kakkonein for early- or mid-stage Parkinson's disease (PD). METHODS: A total of 135 patients with early- or mid-stage PD were enlisted and 116 cases completed the observation, including 40 cases in the acupoint-injection group, 37 cases in the acupuncture group and 39 cases in the medication group. Patients of the acupoint-injection group were treated by injection of kakkonein (2 mL) into bilateral Fengchi (GB 20), once very other day for 8 weeks. For acupuncture intervention, bilateral GB 20 acupoints were punctured with filiform needles, once every other day for 8 weeks. Patients of the medication group were treated by oral administration of compound levodopa (125 mg/time, twice a day) for 8 weeks. The disease severity was assessed by using Unified Parkinson's Disease Rating Scale (UPDRS, version 3. 0) before and after treatment, and one month after the treatment. RESULTS: After the treatment, scores of psychosis, behavior and emotion, daily life activity and motor function were all significantly decreased in the three groups in comparison with pre-treatment in each group (P<0.05), suggesting an improvement of the PD patients' conditions. The therapeutic effect of acupoint-injection and acupuncture groups was markedly superior to that of the medication group (P<0.05). One-month's follow-up showed that the scores of behavior-emotion and daily life activity were obviously lower in the acupoint-injection group than in the acupuncture and medication groups (P<0.05). No significant differences were found between the acupuncture and medication groups in down-regulating scores of behavior-emotion, daily life activity and motor function (P>0.05). CONCLUSION: Acupoint injection of kakkonein can improve patients' behavior, emotion, and daily life activity in early- or mid-stage PD patients and has both short- and longer-term benefits.


Assuntos
Pontos de Acupuntura , Medicamentos de Ervas Chinesas/administração & dosagem , Doença de Parkinson/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Comportamento , Emoções , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Atividade Motora , Doença de Parkinson/fisiopatologia , Doença de Parkinson/psicologia , Resultado do Tratamento
8.
Anal Chim Acta ; 745: 143-8, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22938619

RESUMO

We report a fluorescence approach for the highly selective and sensitive detection of catecholamines using magnetite nanoparticles (Fe(3)O(4) NPs) in the presence of Amplex UltraRed (AUR) and H(2)O(2). Fe(3)O(4) NPs catalyze H(2)O(2)-mediated oxidation of AUR. The resulting product fluoresces (excitation/emission maxima, ca. 568/587nm) more strongly, relative to AUR. When catecholamines bind to Fe(3)O(4), the complexes that are formed induce decreased activity of Fe(3)O(4) NPs, mediated through the coordination between Fe(3+) on the NP surface and the catechol moiety of catecholamines. As a result, Fe(3)O(4) NPs-catalyzed H(2)O(2)-mediated oxidation of AUR is inhibited by catecholamines. The limits of detection for dopamine (DA), L-DOPA, norepinephrine, and epinephrine were 3 nM, 3 nM, 3 nM, and 6 nM, respectively. The Fe(3)O(4) NPs-H(2)O(2)-AUR probe exhibited high selectivity (>1000-fold) toward catecholamines over other tested biomolecules that commonly exist in urine. Four catecholamines had similar sensitivity because the inhibition of the Fe(3)O(4) NPs activity relies on the presence of the catechol moiety. This approach also allowed the determination of tyrosinase activity because tyrosinase catalyzes the conversion of l-tyrosine to L-DOPA. We validated the practicality of the use of the Fe(3)O(4) NPs-H(2)O(2)-AUR probe for the determination of the concentrations of DA in urine samples.


Assuntos
Catecolaminas/urina , Catecóis/química , Corantes Fluorescentes/química , Nanopartículas de Magnetita/química , Catálise , Catecolaminas/química , Dopamina/química , Dopamina/urina , Técnicas Eletroquímicas , Epinefrina/química , Epinefrina/urina , Fluorescência , Humanos , Peróxido de Hidrogênio/química , Levodopa/química , Levodopa/urina , Limite de Detecção , Nanopartículas de Magnetita/ultraestrutura , Masculino , Microscopia Eletrônica de Transmissão , Monofenol Mono-Oxigenase/urina , Norepinefrina/química , Norepinefrina/urina , Oxirredução , Peroxidase , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrometria de Fluorescência , Propriedades de Superfície , Adulto Jovem
9.
Anal Chim Acta ; 703(1): 87-93, 2011 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-21843679

RESUMO

This study reports the development of a reusable, single-step system for the detection of specific substrates using oxidase-functionalized Fe(3)O(4) nanoparticles (NPs) as a bienzyme system and using amplex ultrared (AU) as a fluorogenic substrate. In the presence of H(2)O(2), the reaction pH between Fe(3)O(4) NPs and AU was similar to the reaction of oxidase and the substrate. The catalytic activity of Fe(3)O(4) NPs with AU was nearly unchanged following modification with poly(diallyldimethylammonium chloride) (PDDA). Based on these features, we prepared a composite of PDDA-modified Fe(3)O(4) NPs and oxidase for the quantification of specific substrates through the H(2)O(2)-mediated oxidation of AU. By monitoring fluorescence intensity at 587 nm of oxidized AU, the minimum detectable concentrations of glucose, galactose, and choline were found to be 3, 2, and 20 µM using glucose oxidase-Fe(3)O(4), galactose oxidase-Fe(3)O(4), and choline oxidase-Fe(3)O(4) composites, respectively. The identification of glucose in blood was selected as the model to validate the applicability of this proposed method.


Assuntos
Técnicas Biossensoriais/métodos , Glicemia/análise , Nanopartículas Metálicas , Oxirredutases/química , Adulto , Oxirredutases do Álcool/química , Compostos Alílicos/química , Colina/análise , Fluorescência , Galactose Oxidase/química , Glucose/análise , Glucose Oxidase/química , Humanos , Peróxido de Hidrogênio/química , Concentração de Íons de Hidrogênio , Concentração Osmolar , Oxazinas/química , Tamanho da Partícula , Compostos de Amônio Quaternário/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
10.
J Nanosci Nanotechnol ; 10(10): 6520-6, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21137756

RESUMO

P3HT/graphene nanocomposite was prepared via in-situ reduction of exfoliated graphite oxide in the P3HT polymer matrix, where the exfoliated graphite oxide was formed beforehand via the oxidation of graphite via the Hummers method. The oxidation reaction not only imparts functional groups, such as C=O, C-OH, and C-O-C, to graphite but also causes exfoliation of the resulting graphite oxide. The functional groups render graphite oxide an additional, lower thermal degradation temperature (T(d)) and the exfoliation shifts the XRD pattern towards a much smaller angle. The oxidation of graphite into graphite oxide creates a pleated flaking morphology for graphite oxide as opposed to that of graphite. UV/Vis and photoluminescence (PL) spectra of P3HT/graphene nanocomposite indicate that the existence of graphene does not alter the UV/Vis and PL excitation characteristics of P3HT, and the P3HT/graphene composite has higher electron mobility, a smaller band gap and higher conductivity than the pristine P3HT.

11.
J Nanosci Nanotechnol ; 10(12): 7988-96, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21121288

RESUMO

Nanocomposite comprising Poly(9,9-dioctylfluorene-alt-thiophene) (PDOFT) and graphene sheets was synthesized for the purpose of investigating its enhanced optoelectronic performance caused by the graphene. UV/Vis and photoluminescence spectra of PDOFT/graphene nanocomposite show that the existence of graphene does not alter the optical characteristics wavelength of PDOFT, and both solution samples and thin films emit green light. Meanwhile, the insignificant change in PL quantum efficiency indicates that graphene does not have significant effects on the transfer of excitation energy, the occurrence of self-quenching and the formation of excimer. However, the electric conductivity increases with an increase in the amount of graphene. The ionization potential(HOMO) and the electron affinity(LUMO) measured from the cyclic voltammetry lead to the determination of the optical band gap (Eg(chem)). When used to fabricate an optoelectronic device, the threshold voltage decreases with an increase in the graphene content until an excessive amount of graphene causes an unbalance on the electron and hole mobilities. The device fabricated with PDOFT/graphene with a 5% graphene content has a maximum luminescence of 5908 cd/m2 at a voltage of 9.5 V. The corresponding power efficiency at this maximum luminescence is 0.38 cd/A which is much higher than the device fabricated with pristine PDOFT. From the Admittance spectroscopy of the device, the electron mobility has been proved to increase with the graphene content.

12.
Biosens Bioelectron ; 26(2): 913-7, 2010 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-20656467

RESUMO

We report a one-pot synthesis of poly(diallyldimethylammonium chloride)-coated Fe3O4 (PDDA-Fe3O4) nanoparticles (NPs) by the coprecipitation method. The formed PDDA-Fe3O4 NPs were characterized by powder X-ray diffraction and superconducting quantum interference device. The crystalline structure and superparamagnetic property of PDDA-Fe3O4 NPs were found to be similar to those of Fe3O4 NPs, indicating that the presence of PDDA does not affect the formation of Fe3O4 NPs. Moreover, glucose oxidase (GOx) and citrate-capped gold (Au) NPs, having negative charges, can be easily self-assembled at the surface of cationic PDDA-Fe3O4 NPs. Without the requirement of a peroxidise enzyme, the composites of PDDA-Fe3O4 NPs and GOx effectively catalyzes the H2O2-mediated oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate acid) (ABTS) in the presence of glucose. This colorimetric method enables the analysis of glucose with a minimum detectable concentration that corresponds to 30 µM. We validate the applicability of this method by determining the concentration of glucose in serum samples. In another application, the composites of PDDA-Fe3O4 and Au NPs were shown to be capable of selectively enriching cysteine-containing peptides through the formation of Au-S bonds. The extracted peptides can be easily detected by matrix-assisted laser desorption/ionization-time of flight mass spectrometer. Both applications open up a new way for the synthesis of bifunctional NPs.


Assuntos
Técnicas Biossensoriais/instrumentação , Materiais Revestidos Biocompatíveis/química , Colorimetria/instrumentação , Glucose/análise , Nanopartículas de Magnetita/química , Polietilenos/química , Compostos de Amônio Quaternário/química , Compostos de Sulfidrila/isolamento & purificação , Desenho de Equipamento , Análise de Falha de Equipamento
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