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1.
Artigo em Inglês | MEDLINE | ID: mdl-32043718

RESUMO

An organic crystal of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (pCBP) exhibits time-dependent afterglow color from blue to orange over 1 s. Both experimental and computational data confirm that the color evolution results from well-separated, long-persistent thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP) with different but comparable decay rates. TADF is enabled by a small S1 -T1 energy gap of 0.7 kcal mol-1 . The good separation of TADF and RTP is due to a 11.8 kcal mol-1 difference in the S0 energies of the S1 and T1 structures, indicating that apart from the excited-state properties, tuning the ground state is also important for luminescence properties. This afterglow color evolution of pCBP allows its applications in anticounterfeiting and data encryption with high security levels.

2.
Analyst ; 2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32103211

RESUMO

In this work, a new kind of dendritically amplified fluorescent signal probe on SiO2 microspheres was controllably fabricated by the terminal deoxynucleotidyl transferase (TdT)-catalyzed incorporation of nucleotides combined with bio-barcode (BBC) amplification for the ultrasensitive detection of Hg2+. A thymine T-Hg2+-T hairpin structure was first formed and further initiated the strand displacement amplification (SDA) reaction, generating a mimic target (MT). MT hybridized with a capture probe 1 (C1) on SiO2 microspheres, and the 3'-hydroxyl (OH) termini of MT initiated TdT-based DNA extension, producing abundant poly-guanine sequences (G1). Then, G1 hybridized with a capture probe 2 (C2) with abundant cytosine (C) species to assemble multiple C2/reporter probe-AuNPs onto the SiO2 microspheres. The reporter DNA further initiated TdT-based extension with a poly-T sequence (T1) to link large numbers of signal probes, which generated a very high fluorescence signal for the ultrasensitive detection of target Hg2+. This TdT-based signal amplification method coupled with SDA exhibits extraordinary sensitivity for Hg2+ assay with a limit down to 1.0 aM. The proposed highly sensitive fluorescence strategy holds great potential for detecting targets in environmental and biological fields.

3.
Genes (Basel) ; 11(2)2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32053967

RESUMO

The Apollo butterfly, Parnassius glacialis, is one of the most charming members of its genus and includes two subspecies locally distributed in montane areas of south-central China and Japan. In this study, we investigated the genetic structure and demographic history of P. glacialis by analyzing partial sequences of four mitochondrial genes and nuclear single nucleotide polymorphisms (SNPs) via genotyping-by-sequencing (GBS) of samples from nearly the entire known distributional range in China. The mitochondrial DNA (mtDNA) data demonstrated that a total of 39 haplotypes were present, and the species was estimated to have diverged about 0.95 million years ago during the middle Pleistocene transition into two main clades that likely formed during the Kunlun-Huanghe tectonic movement. The two clades then dispersed independently in distinct geographic areas alongside the mountainous routes in central and southern China, most likely driven by the Pleistocene glacial-interglacial cycles. Nuclear SNP analysis was generally congruent with mtDNA results at the individual level. A minor incongruence of genetic structures that was detected between mtDNA and nuclear SNP data from the Laojunshan and Tiantangzhai populations was likely due to secondary contact and male-biased dispersal. Our work demonstrates that complicated dispersal-vicariance evolutionary processes likely led to the current geographic distribution of P. glacialis in China, particularly the uplift of the Qinghai-Tibet Plateau and related climatic oscillations during the Quaternary period.

4.
Environ Sci Pollut Res Int ; 27(2): 1835-1851, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31760615

RESUMO

The national unified carbon trading market has been officially launched at the end of 2017. The carbon emission quotas should be primary concern, which can be allocated in the form of free and paid ways. However, few literatures studied the economic and environmental impacts of quotas allocation. Thus, this paper constructs 7 scenarios and employs a dynamic, recursive computable general equilibrium (CGE) model to simulate carbon trading market, to probe the relationship between quota allocation and carbon price, and the economic and environmental impact of carbon trading scheme (ETS). Empirical results indicate (1) carbon price has an upward trend with time, which reflects a corresponding increase in emission reduction pressure. Specifically, carbon price increases from 12.44-90.57 CNY/t in 2017 to 65.20-523.44 CNY/t in 2030. In addition, whether under carbon intensity criterion (CIC) or carbon emission criterion (CEC), there is a positive relationship between carbon price and free allocation ratio due to the change of the relationship between supply and demand of quota. With a given free allocation ratio, the price formed with CIC grows faster than that with CEC. (2) Compared with the benchmark scenario, the GDP of China decreases in all scenarios. However, a high level of free allocation ratio combined with CIC may prevent GDP dropping too fast. (3) As for industrial output, covered industries in ETS undertake the largest output losses with an average decline by 4.03-13.60%. Similar to GDP variation, a high free allocation ratio combined with CIC is helpful for sustainable development of industry. (4) Carbon trading has a remarkable effect on emission reductions both in covered and uncovered industries of ETS. Free allocation will reduce market efficiency, which implies it should be cut down gradually at the later stages.

5.
Biosens Bioelectron ; 147: 111779, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31630031

RESUMO

In this study, a coumarin-appended cyclometalated iridium (III) complex was prepared and demonstrated to be an efficient photoelectrochemical (PEC) active species with stable and reproducible cathodic photocurrent illuminated by visible light. A gold nanoparticles (AuNPs)-based PEC probe was assembled using the as-prepared iridium (III) complex as signal reporter. Integrating aptamer/protein proximity binding-triggered strand displacement and catalytic hairpin assembly (CHA) amplification strategy, an enzyme-free and sensitive PEC assay was developed. Benefiting from superior photon-to-current conversion character of the iridium (III) complex and effective amplification strategy, the proposed assay exhibited enhanced sensitivity for thrombin detection with a detection limit of 23 fM. It also showed a high specificity in serum samples. This study further demonstrated that cyclometalated iridium (III) complexes could be adopted as favorable photoactive material for bioanalysis by improving their ability of absorbance in the visible region.

6.
Anal Chim Acta ; 1090: 143-150, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31655639

RESUMO

A sandwich-type photoelectrochemical (PEC) immunosensor was constructed for sensitive detection of prostate specific antigen (PSA). It was based on electrochemically reduced graphene oxide-TiO2 (ERGO-TiO2) as photoelectrochemical platform to immobilize capture antibody (Ab1). Then, quinone-rich polydopamine nanospheres (PDANS) loaded detection antibody (Ab2) and photocurrent signal label, l-cysteine-coated cadmium sulfide quantum dots (CdSQDs). ERGO-TiO2 displayed greatly improved photocurrent response to white light. CdSQDs conjugated with PDANS further amplified photocurrent signal because of the good conductivity of PDANS and ERGO. The increased photocurrent showed a linear correlation with PSA in the concentration range from 0.02 pg mL-1 to 200 ng mL-1 with the detection limit of 6.8 fg mL-1. It also revealed high selectivity and good stability.

7.
Clin Infect Dis ; 2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31549147

RESUMO

BACKGROUND: The emergence of multidrug-resistant tuberculosis (MDR-TB) poses a serious obstacle to global TB control programmes. METHODS: We carried out a prospective, randomised multicenter study in China focused on the potential of shorter regimen containing clofazimine (CFZ) for the treatment of MDR-TB. 135 MDR-TB cases met eligibility requirements and were randomly stratified into control group or experimental group. Patients in the control group received 18-month treatment regimen, whereas patients in the experimental group received 12-month treatment regimen containing CFZ. RESULTS: At the completion of treatment period, the difference in sputum-culture conversion between the experimental group and the control group was not significant. Notably, by the end of the 3-month treatment, 68.7% patients receiving experimental regimen had sputum-culture conversion as compared with 55.9% of those receiving control regimen; this was a significant difference, suggesting an early sputum conversion (P=0.04). 67 adverse events were reported in 56 patients in this study, including 32 in the control group and 35 in the experimental group, respectively. No significant difference in the overall incidence of adverse events was observed between the two groups. CONCLUSION: The MDR-TB patients initiated with the shorter regimen containing CFZ have a comparable successful outcome rate when compared to those with the standard regimen. The patients assigned in the experimental group achieve more rapid sputum culture conversion, reflecting the superior antimicrobial activity against MDR-TB.

8.
Parasitol Res ; 118(10): 2885-2890, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31448385

RESUMO

Accurate discrimination of the Schistosoma japonicum cercariae gender is very important for establishing monosexual infection animal models and for standardizing the real intensity of infection. In this study, a multiplex PCR technique consisting of two pairs of primers, of which one amplifies a 185-bp band specific for the W chromosome and the other amplifies a 420-bp band for the Z chromosome, was established to sex the S. japonicum cercariae. For male cercariae (ZZ), a single 420-bp band is expected, and for female cercariea (ZW), two distinct 185-bp and 420-bp bands can be observed. There was no cross-reaction with S. mansoni, S. haematobium, Clonorchis sinensis, Paragonimus westermani, and Trichinella spiralis. After sexing the cercariae escaped from a single snail, mice in group A were infected with 60 male cercariae and mice of group B were infected with 40 female cercariae. Meanwhile, mice in group C were infected with 10 male and 10 female cercariae that were sexed by multiplex PCR. At 45 days postinfection, male and female adult worms were recovered to verify the accuracy of multiplex PCR for sexing S. japonicum cercariae and to calculate the male and female survival rate and paired worm ratio. Our results showed that the multiplex PCR technique could distinguish male cercariae with 100% accuracy. However, sometimes the discrimination results of multiplex PCR mis-scored mixed sexual cercariae as female cercariae. The mean male adult worm burden in mice of group C was 10.7 ± 2.4, and the mean female adult worm burden was 7.7 ± 2.5. There was a significant difference between the male worm burden and female worm burden in group C. The P value was 0.013. The real paired worm ratio of group C was 74.2% (95%CI 56.6~91.8%). These results demonstrated a male-biased sex ratio in the mice model with equilibrated sex ratio cercariae infection, as predicted by our multiplex PCR technique. In conclusion, our multiplex PCR technique is an effective tool for sexing S. japonicum cercariae, especially for distinguishing male cercariae, which is of great value for establishing monosexual cercariae infection mice models to harvest male adult worms for anti-schistosomal drug screening.


Assuntos
Cercárias/genética , Schistosoma japonicum/genética , Caracteres Sexuais , Animais , Modelos Animais de Doenças , Feminino , Masculino , Camundongos , Reação em Cadeia da Polimerase Multiplex/métodos , Schistosoma japonicum/efeitos dos fármacos , Caramujos/parasitologia
9.
Immunology ; 158(4): 296-303, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31436861

RESUMO

Hepatic fibrosis induced by schistosomes is regulated by a complex network of cytokines. T helper type 9 (Th9) cells are a new type of effector T helper cells, which mainly secrete the specific cytokine interleukin-9 (IL-9). Interleukin-9 has been shown to contribute to liver fibrosis in patients with chronic hepatitis B and in a mouse model due to carbon tetrachloride. However, the role of IL-9 in schistosomiasis fibrosis remains unknown. In this study, we investigated the roles of IL-9 in schistosomiasis through in vivo and in vitro studies. The in vivo studies found that neutralization of IL-9 reduced liver granulomatous inflammation and collagen deposition around parasite eggs. The in vitro studies found that the treatment of primary hepatic stellate cells with IL-9 induced a significant increase of collagen and α-smooth-muscle actin. Moreover, we also described the dynamics and relevance of IL-9 and IL-4 in mice infected with Schistosoma japonicum. We found that IL-9 might appear more quickly and at higher levels than IL-4. Hence, our findings indicated that IL-9 might play a role in regulating hepatic fibrosis in early-stage schistosomiasis and become a promising approach for regulating hepatic fibrosis caused by S. japonicum.


Assuntos
Granuloma/terapia , Inflamação/terapia , Interleucina-9/metabolismo , Hepatopatias/terapia , Schistosoma japonicum/fisiologia , Esquistossomose Japônica/terapia , Linfócitos T Auxiliares-Indutores/imunologia , Animais , Células Cultivadas , Colágeno/metabolismo , Modelos Animais de Doenças , Feminino , Fibrose , Granuloma/imunologia , Humanos , Inflamação/imunologia , Interleucina-4/metabolismo , Interleucina-9/antagonistas & inibidores , Hepatopatias/imunologia , Camundongos , Camundongos Endogâmicos , Contagem de Ovos de Parasitas , Esquistossomose Japônica/imunologia
10.
Parasit Vectors ; 12(1): 199, 2019 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-31053083

RESUMO

BACKGROUND: Schistosomiasis is a debilitating neglected tropical disease that affects approximately 190 million people around the world. Praziquantel (PZQ) is the only drug available for use against all Schistosoma species. Although PZQ has a high efficacy, recognized concerns have prompted the development of new, alternative drugs for repeated use in endemic areas where PZQ efficacy against strains of Schistosoma is reduced. A hybrid drug containing different pharmacophores within a single molecule is a promising strategy. Our earlier in vivo studies showed the significant antiparasitic activity of a praziquantel derivative, DW-3-15, against Schistosoma japonicum. In the present study, DW-3-15 was synthesized in large amounts by a pharmaceutical company and its schistosomicidal efficacy and stability were further confirmed. Parameters such as parasite viability, pairing and oviposition were evaluated in vitro. An in vivo study was conducted to assess the effect of commercial DW-3-15 on worm burden, egg production and diameter of granulomas. Additionally, to gain insight into the mechanism of action for DW-3-15, morphological changes in the tegument of S. japonicum were also examined. RESULTS: The in vitro study showed the antiparasitic activity of DW-3-15 against S. japonicum, with significant reductions in viability of adult and juvenile worms, worm pairings and egg output. Compared to PZQ, DW-3-15 induced similar ultrastructural changes and evident destruction of the tegument surface in male worms. In vivo, the oral administration of DW-3-15 at a dose of 400 mg/kg per day for five consecutive days in mice significantly reduced the total worm burden and number of eggs in the liver. Histological analysis of the livers showed a marked reduction in the average diameter of the egg granuloma. CONCLUSIONS: Our findings suggest that DW-3-15, a PZQ derivative with the prospect of commercial production, can be developed as a potential promising schistosomicide.


Assuntos
Praziquantel/administração & dosagem , Schistosoma japonicum/efeitos dos fármacos , Esquistossomose Japônica/parasitologia , Esquistossomicidas/administração & dosagem , Administração Oral , Animais , Feminino , Humanos , Fígado/parasitologia , Masculino , Camundongos Endogâmicos ICR , Contagem de Ovos de Parasitas , Praziquantel/química , Schistosoma japonicum/crescimento & desenvolvimento , Schistosoma japonicum/fisiologia , Esquistossomose Japônica/tratamento farmacológico , Esquistossomicidas/química
11.
Mikrochim Acta ; 186(6): 347, 2019 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-31079210

RESUMO

Gold nanoparticles (AuNPs) with a size of ~3 nm were placed on a thionine-multiwalled carbon nanotube (Thi-CNTs) conjugate to form a novel AuNP-Thi-CNTs nanocomposite. Its morphology and composition were characterized by transmission electron microscopy, atomic force microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The nanocomposite was placed on an electrode and used as a redox-active signaling interface to fabricate a ratiometric electrochemical aptasensor for 17ß-estradiol (E2). The potentiostatic insertion method was applied to insert an aptamer against E2 into a thin alkane monolayer to warrant an adequate distance between aptamers. The aptamer against E2 acts as both a collector and separator to specifically bind E2. The electrode displays two peak signals (at +0.50 V vs. SCE for E2; and at -0.32 V for Thi) which increase and decrease, respectively, in the 12 pM to 60 nM E2 concentration range. Therefore, the current ratio can be used to reliably, reproducibly, and sensitively quantify the concentration of E2. Graphical abstract Schematic presentation of a novel AuNP-Thi-CNTs nanocomposite. AuNP-Thi-CNTs showed good electrocatalytic oxidation to E2. AuNP-Thi-CNTs was used as self-redox signal interface to fabricate aptasensor. Dual signals of extrinsic E2 and inner Thi was applied to monitor the concentration of E2.

12.
Exp Ther Med ; 17(1): 147-152, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30651775

RESUMO

The present study aimed to assess the usefulness of soluble triggering receptor expressed on myeloid cells 1 (sTREM-1) in the diagnosis of ventilator-associated pneumonia (VAP) in paediatric patients with congenital heart disease (CHD) following cardiac surgery. The current prospective study enrolled 48 patients with congenital heart diseases who were suspected of having VAP; these patients were undergoing cardiac surgery between August 2016 and October 2017 in the Cardiac Intensive Care Unit of Shanghai Children's Medical Center (Shanghai, China). A total of 31 patients were diagnosed with VAP using a polymerase chain reaction (PCR) assay, while 17 patients without VAP were designated as the Non-VAP group. A bronchoscopy was performed and samples were collected for measurement on the day that VAP was diagnosed. The sTREM-1 levels were measured in bronchoalveolar lavage fluid (BALF) and exhaled ventilator condensate (EVC). BALF specimens were also sent to the microbiology laboratory for PCR assays and quantitative culturing. The positive detection rate of bacteria using the PCR assay and traditional culture was 64.6% (31/48) and 39.6% (19/48). sTREM-1 was significantly higher in the BALF (146.21 pg/ml vs. 118.06 pg/ml) and EVC (125.29 pg/ml vs. 120.48 pg/ml) of patients with VAP demonstrated compared with the patients without VAP. The findings suggest that the detection of sTREM-1 in BALF and EVC samples may be useful for the diagnosis of VAP following heart surgery in children.

13.
Carbohydr Polym ; 205: 492-499, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30446133

RESUMO

Lithium resources are attractive for different applications because of their specific properties. Therefore, it is more significant to find a cost-effective and environment-friendly method to selective adsorption and recovery of Li+. In this work, a renewable and easy degradable CA/CS hybrid membrane was modified with polydopamine as adhesion layer to anchored TiO2. The simple imprinting process could be realized by hydrolysis polymerization. The adsorption process followed Langmuir isotherm model and pseudo-second-order kinetic equation were researched in detail. The results displayed the maximum adsorption capacity is 20.08 mg g-1 for Li+. The selectivity factors of Li+ to Na+, K+, Mg2+ and Ca2+ are 1.78, 2.43, 2.60 and 3.61, respectively, which mainly attributed to imprinting effect. The LIICMs also exhibited the superior reusability and durability. Thus, the LIICMs provide a powerful tool for selective separation and recovery of Li+ from mixed solutions.

14.
Nucl Med Commun ; 40(3): 206-211, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30570518

RESUMO

AIM: The aim of this study is to develop and validate a new method to diagnose apical hypertrophic cardiomyopathy (AHCM) by the integral quantitative analysis of myocardial perfusion and wall thickening from gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). PATIENTS AND METHODS: Twenty-two consecutive patients, who showed T wave inversion of at least 3 mm in precordial leads and sinus rhythm in ECG, were enrolled. All the patients underwent cardiac magnetic resonance (CMR), gated rest SPECT MPI and echocardiography. According to CMR diagnostic results, 13 patients were categorized as in the AHCM group and the remaining nine patients were categorized as in the non-AHCM group. Operators who were blinded to the CMR diagnosis independently performed the diagnosis by gated SPECT MPI. The regions of interest inside the apical hotspots on the perfusion polar map were drawn and the mean values of wall thickening in the drawn region of interests were calculated. Using MRI diagnosis as the gold standard, AHCM was diagnosed based on receiver operating characteristic analysis of the mean wall thickening in the apical perfusion hotspot. The area under curve, sensitivity, specificity, and accuracy of our method were 0.97, 100%, 89%, and 95%, respectively. CONCLUSION: Our new method has high sensitivity, specificity, and accuracy against CMR diagnosis. It has great promise to become a clinical tool in the diagnosis of AHCM.


Assuntos
Tomografia Computadorizada por Emissão de Fóton Único de Sincronização Cardíaca/métodos , Cardiomiopatia Hipertrófica/diagnóstico por imagem , Imagem de Perfusão do Miocárdio/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Curva ROC
15.
Int J Cancer ; 144(5): 1037-1048, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30070702

RESUMO

Gene amplification, which involves the two major topographical structures double minutes (DMs) and homegeneously stained region (HSR), is a common mechanism of treatment resistance in cancer and is initiated by DNA double-strand breaks. NHEJ, one of DSB repair pathways, is involved in gene amplification as we demonstrated previously. However, the involvement of homologous recombination, another DSB repair pathway, in gene amplification remains to be explored. To better understand the association between HR and gene amplification, we detected HR activity in DM- and HSR-containing MTX-resistant HT-29 colon cancer cells. In DM-containing MTX-resistant cells, we found increased homologous recombination activity compared with that in MTX-sensitive cells. Therefore, we suppressed HR activity by silencing BRCA1, the key player in the HR pathway. The attenuation of HR activity decreased the numbers of DMs and DM-form amplified gene copies and increased the exclusion of micronuclei and nuclear buds that contained DM-form amplification; these changes were accompanied by cell cycle acceleration and increased MTX sensitivity. In contrast, BRCA1 silencing did not influence the number of amplified genes and MTX sensitivity in HSR-containing MTX-resistant cells. In conclusion, our results suggest that the HR pathway plays different roles in extrachromosomal and intrachromosomal gene amplification and may be a new target to improve chemotherapeutic outcome by decreasing extrachromosomal amplification in cancer.


Assuntos
Cromossomos/genética , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/genética , Resistencia a Medicamentos Antineoplásicos/genética , Amplificação de Genes/genética , Recombinação Homóloga/genética , Metotrexato/farmacologia , Ciclo Celular/genética , Linhagem Celular Tumoral , Núcleo Celular/genética , Aberrações Cromossômicas , Quebras de DNA de Cadeia Dupla , Células HT29 , Humanos
16.
Nanomaterials (Basel) ; 8(12)2018 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-30544495

RESUMO

TiO2/Ag bilayer films sputtered onto a 2D polystyrene (PS) bead array in a magnetron sputtering system were found to form a nanocap-shaped nanostructure composed of a TiO2-Ag composite on each PS bead, in which the Ag nanoparticles were trapped partially or fully in the TiO2 matrix, depending on the TiO2 thickness. X-ray Photoelectron Spectroscopy (XPS) results showed the opposite shifts of binding energy for Ti 2p and Ag 3d, indicating the transfer of electrons from metallic Ag to TiO2 owing to the Ag-O-TiO2 composite formation. UV-Vis absorption spectra showed the blue shifts of the surface plasma resonance peaks, and the maximum absorption peak intensity was obtained for TiO2 at 30 nm. The surface-enhanced Raman scattering (SERS) peak intensity first increased and then decreased when the TiO2 thickness changed. The observations of SERS, XPS, and UV-Vis absorption spectra were explained by the dependency of the charge-transfer process on TiO2 thickness, which was ascribed to the changing dielectric properties in the metal/semiconductor system.

17.
Anal Chem ; 90(24): 14239-14246, 2018 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-30427167

RESUMO

In this study, a novel iridium(III) complex-based photoactive species, [(C6)2Ir(dppz)]+PF6-, was synthesized with coumarin 6 (C6) as a cyclometalated ligand and dipyrido[3,2-a:2',3'-c]phenazine (dppz) as an ancillary ligand. The photophysical and electrochemical properties of the complex have been investigated. It exhibits intense visible-light absorption with a molar extinction coefficient up to 9.8 × 104 M-1 cm-1 at 485 nm. The photoelectrochemical (PEC) properties of [(C6)2Ir(dppz)]+PF6- were also investigated by spin-coating on the ITO electrode. By illumination with 490 nm light, cathodic photocurrent up to 260 nA/cm2 was observed at 0 V bias potential with dissolved O2 as an electron acceptor. On the other hand, an anodic photocurrent was generated in the presence of triethanolamine (TEOA) as a sacrificial electron donor. The probable mechanisms for photocurrent generation were deduced by UV-vis absorption spectrum and cyclic voltammetry data. Adopting [(C6)2Ir(dppz)]+PF6- as photoactive intercalator, a visible-light driven PEC detection platform was successfully fabricated for microRNA detection based on an enzyme-free hybridization chain reaction as an amplification strategy. Expected, the PEC platform for microRNA-122b detection showed excellent linear response with a limit of detection down to 0.23 fM (3σ), comparable or superior to those of the reported analogous approaches. Encouragingly, this study would provide a new approach to exploit efficient photoactive species for PEC bioanalysis.


Assuntos
Complexos de Coordenação/química , Cumarínicos/química , Técnicas Eletroquímicas/métodos , Irídio/química , Luz , MicroRNAs/análise , Tiazóis/química , Linhagem Celular Tumoral , DNA/química , DNA/metabolismo , Eletrodos , Elétrons , Etanolaminas/química , Humanos , Limite de Detecção , MicroRNAs/metabolismo , Técnicas de Amplificação de Ácido Nucleico , Compostos de Estanho/química
18.
J Am Chem Soc ; 140(44): 15099-15113, 2018 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-30362731

RESUMO

A recent experimental study reported a visible-light-mediated aerobic oxidative coupling reaction of phenol with alkynes that produces hydroxyl-functionalized aryl ketones using inexpensive CuCl as catalyst under mild conditions. Here we apply the complete active space self-consistent field (CASSCF) method and multistate second-order perturbation (MS-CASPT2) theory in combination with density functional theory (DFT) to systematically explore the entire photocatalytic reaction between phenol and phenylacetylene in acetonitrile solution in the presence of molecular oxygen and CuCl. Our main findings are as follows: (1) The visible-light-driven conversion of phenylacetylene to PhCCCu(I) occurs thermally because of efficient excited-state deactivation to the S0 state. (2) The single electron transfer from PhCCCu(I) to molecular oxygen that leads to the PhCCCu(II) cation takes place in the T1 state after an efficient S1 → T1 intersystem crossing. (3) During the initial oxidation of phenol, molecular oxygen prefers to attack the para position of the phenol radical intermediate to produce 1,4-benzoquinone, which further reacts with PhCCCu(II) to generate para-hydroxyl-substituted aryl ketones; this is the origin of the experimentally observed regioselectivity. (4) The C≡C bond of the phenylacetylene moiety is not activated by the triplet-state single electron transfer from PhCCCu(I) to molecular oxygen but is cleaved at a later stage, in the [2+2] cycloaddition between PhCCCu(II) and 1,4-benzoquinone. (5) The substrate phenol plays an active role in several hydrogen transfer and decarboxylation reactions; the barriers to these phenol-assisted reactions are lower than those for the corresponding direct or water-assisted reactions, which explains the experimental finding that adding water does not enhance the photocatalytic reaction yield. In summary, while supporting the general features of the experimentally proposed mechanism, our computational study provides detailed mechanistic insights that should be useful for understanding and further improving visible-light-induced copper-catalyzed coupling reactions.

19.
J Agric Food Chem ; 66(41): 10748-10759, 2018 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-30280897

RESUMO

ß-Sitosterol is a well known phytosterol in plants, but owing to its poor solubility in typical media, determining its cellular mechanisms has been proven to be difficult. In this study, we investigated the anti-inflammatory activity of ß-sitosterol (BSS) isolated from Moringa oleifera in two cell lines. Over a dose range of 7.5 to 30 µM, BSS dispersed well in the medium as nanoparticles with diameters of 50 ± 5 nm and suppressed the secretion of inflammatory factors from keratinocytes and macrophages induced by PGN, TNF-α, or LPS, such as TNF-α, IL-1ß, IL-6, IL-8, and ROS, separately. In addition, BSS significantly reduced the expression of NLRP3, a key component of NLRP3 inflammasomes, and inhibited the activation of caspase-1. There was partial inhibition of NF-κB in macrophages. This is the first study to report an increase in the solubility of nearly water-insoluble phytosterols via the formation of nanoparticles and to delineate the formulation's capacity to inhibit the signal transduction pathways of inflammation in macrophages.


Assuntos
Anti-Inflamatórios/química , Moringa oleifera/química , Nanopartículas/química , Sitosteroides/química , Animais , Anti-Inflamatórios/isolamento & purificação , Anti-Inflamatórios/uso terapêutico , Antioxidantes/química , Antioxidantes/isolamento & purificação , Antioxidantes/uso terapêutico , Caspase 1/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Citocinas/metabolismo , Composição de Medicamentos , Humanos , Queratinócitos/metabolismo , Macrófagos/metabolismo , Camundongos , Tamanho da Partícula , Transdução de Sinais/efeitos dos fármacos , Sitosteroides/isolamento & purificação , Sitosteroides/uso terapêutico , Solubilidade , Propriedades de Superfície
20.
J Colloid Interface Sci ; 531: 1-10, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30015165

RESUMO

A tremendous effort has been made for the synthesis and multifunction of environmentally responsive and selective separation membranes. With the bioinspired design of polydopamine (pDA)-assisted inorganic film, we proposed a simple, yet efficient, thermo-responsive cell culture substrate. Herein, a Ag/TiO2/pDA-based nanocomposite structure was initially obtained, and the ciprofloxacin-imprinted membranes (MINCMs) with thermo-responsive recognition sites were then synthesized by using NIPAm as backbone monomer. The opto-thermally responsive molecularly imprinted membranes (OT-MIMs) were obtained through in situ reduction of HAuCl4 on membrane surfaces, Au nanoparticles were used as the light-heat converters. The light-switching principle was elaborated as well as the energy conversions that took place in this system. These conformational changes finally allowed the constructions or destructions of ciprofloxacin-imprinted sites. Due to the formation of the opto-thermally responsive ciprofloxacin-imprinted sites, rapid adsorption dynamics and opto-thermally responsive perm-selectivity toward templates were both achieved. Therefore, 58.65 mg/g of adsorption capacity and 4.91 of permselectivity factor from OT-MIMs were successfully obtained. Importantly, the as-designed bioinspired strategy led to a state-of-the-art design that was capable of reversibly controlling the flow rate (J) of ciprofloxacin from 12.10 to 4.93 mg min-1 cm-2 in less than a few minutes using light.


Assuntos
Antibacterianos/isolamento & purificação , Ciprofloxacino/isolamento & purificação , Indóis/química , Impressão Molecular , Nanocompostos/química , Polímeros/química , Prata/química , Titânio/química , Acrilamidas/química , Adsorção , Antibacterianos/química , Sítios de Ligação , Ciprofloxacino/química , Luz , Membranas Artificiais , Nanocompostos/ultraestrutura , Temperatura Ambiente
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