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Materials with tunable long persistent luminescence (LPL) properties have wide applications in security signs, anti-counterfeiting, data encrypting, and other fields. However, the majority of reported tunable LPL materials are pure organic molecules or polymers. Herein, a series of metal-organic coordination polymers displaying color-tunable LPL were synthesized by the self-assembly of HTzPTpy ligand with different cadmium halides (X=Cl, Br, and I). In the solid state, their LPL emission colors can be tuned by the time-evolution, as well as excitation and temperature variation, realizing multi-mode dynamic color tuning from green to yellow or green to red, and are the first such examples in single-component coordination polymer materials. Single-crystal X-ray diffraction analysis and theoretical calculations reveal that the modification of LPL is due to the balanced action from single molecule and aggregate triplet excited states caused by an external heavy-atom effect. The results show that the rational introduction of different halide anions into coordination polymers can realize multi-color LPL.
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Energy-metabolism oscillations (EMO) are ultradian biological rhythms observed in in aerobic chemostat cultures of Saccharomyces cerevisiae. EMO regulates energy metabolism such as glucose, carbohydrate storage, O2 uptake, and CO2 production. PSK1 is a nutrient responsive protein kinase involved in regulation of glucose metabolism, sensory response to light, oxygen, and redox state. The aim of this investigation was to assess the function of PSK1 in regulation of EMO. The mRNA levels of PSK1 fluctuated in concert with EMO, and deletion of PSK1 resulted in unstable EMO with disappearance of the fluctuations and reduced amplitude, compared with the wild type. Furthermore, the mutant PSK1Δ showed downregulation of the synthesis and breakdown of glycogen with resultant decrease in glucose concentrations. The redox state represented by NADH also decreased in PSK1Δ compared with the wild type. These data suggest that PSK1 plays an important role in the regulation of energy metabolism and stabilizes ultradian biological rhythms. These results enhance our understanding of the mechanisms of biorhythms in the budding yeast.
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Metabolismo de los Hidratos de Carbono/fisiología , Metabolismo Energético/fisiología , Proteínas Quinasas/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Metabolismo de los Hidratos de Carbono/genética , Metabolismo Energético/genética , Regulación Fúngica de la Expresión Génica , Técnicas de Inactivación de Genes , Glucosa/metabolismo , Oxígeno/metabolismo , Proteínas Quinasas/genética , ARN Mensajero/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Transcriptoma , Ritmo Ultradiano/fisiologíaRESUMEN
A novel molecularly imprinted quartz crystal microbalance (QCM) sensor was successfully prepared for selective determination of sialic acid (SA) in human urine samples. To obtain the QCM sensor, we first modified the gold surface of the QCM chip by self-assembling of allylmercaptane to introduce polymerizable double bonds on the chip surface. Then, SA molecularly imprinted polymer (MIP) nanofilm was attached to the modified QCM chip surface. For comparison, we have also characterized the nonmodified and improved surfaces of the QCM sensor by using atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. We then tested the selectivity and detection limit of the imprinted QCM sensor via a series of adsorption experiments. The results show a linear response in the range of 0.025-0.50 µmol L-1 for sialic acid. Moreover, the limit of detection (LOD) of the prepared imprinted QCM sensor was found to be 1.0 nmol L-1 for sialic acid, and high recovery values range from 87.6 to 108.5% with RSD < 8.7 (n = 5) for the spiked urine sample obtained. Overall, this work presents how a novel QCM sensor was developed and used to detect sialic acid in human urine samples. Graphical abstract Specific recognition of sialic acid by the MIP-QCM sensor system.
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Impresión Molecular/métodos , Ácido N-Acetilneuramínico/orina , Polímeros/química , Tecnicas de Microbalanza del Cristal de Cuarzo/métodos , Diseño de Equipo , Humanos , Límite de Detección , Impresión Molecular/instrumentación , Nanoestructuras/química , Tecnicas de Microbalanza del Cristal de Cuarzo/instrumentación , Propiedades de SuperficieRESUMEN
Density functional calculations are utilized to explore the hydrolysis mechanisms of the phosphomonoester 4-nitrophenyl phosphate catalyzed by a symmetrical zinc(II) complex. The formation process and properties of the active catalyst are verified. Eight plausible mechanisms are proposed and categorized into three groups. All of the proposed mechanisms, except for Mechanism 7 (see text), are S(N)2-type addition-substitution reaction pathways. Nucleophilic attack at the ortho position occurs in Mechanism 7 with a relatively high reaction barrier. Mechanisms 1 and 2 in the monocatalyst model, Mechanisms 5 to 7 in the sandwich-dual-catalyst model, as well as the nucleophilic addition-substitution step in Mechanism 8 are concerted reaction pathways, whereas the rest appear to occur in a stepwise manner. Meanwhile, the explicit solvent model is utilized to consider direct hydrogen bonds and solvation interactions and these results indicate that the added water molecule is involved in the hydrolysis process, but does not change the mechanisms significantly. Mechanism 8, with the lowest reaction barrier, is the most favored reaction pathway of the eight proposed mechanisms, although Mechanisms 1, 4, and 6 are in competition with Mechanism 8. In consideration of the zinc(II) complex concentration, Mechanism 1 is only the predominant reaction pathway at a low zinc(II) complex concentration; Mechanisms 4 and 6 tend to be more competitive with increasing concentration of the zinc(II) complexes, and Mechanism 8 is favored at high zinc(II) complex concentrations. Our calculated results are consistent with, and can be used to systematically interpret, experimental observations. More importantly, insightful suggestions are made regarding the catalyst design and selection of the reaction environment.
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Complejos de Coordinación/química , Iminas/química , Organofosfatos/química , Zinc/química , Catálisis , Enlace de Hidrógeno , Hidrólisis , Modelos Moleculares , Nitrofenoles/química , Compuestos Organofosforados/químicaRESUMEN
The mechanisms and enantioselectivities of the dirhodium (Rh2L4, L = formate, N-methylformamide, S-nap)-catalyzed intramolecular C-H aminations of 3-phenylpropylsulfamate ester have been investigated in detail with BPW91 density functional theory computations. The reactions catalyzed by the Rh2(II,II) catalysts start from the oxidation of the Rh2(II,II) dimer to a triplet mixed-valent Rh2(II,III)-nitrene radical, which should facilitate radical H-atom abstraction. However, in the Rh2(formate)4-promoted reaction, as a result of a minimum-energy crossing point (MECP) between the singlet and triplet profiles, a direct C-H bond insertion is postulated. The Rh2(N-methylformamide)4 reaction exhibits quite different mechanistic characteristics, taking place via a two-step process involving (i) intramolecular H-abstraction on the triplet profile to generate a diradical intermediate and (ii) C-N formation by intersystem crossing from the triplet state to the open-shell singlet state. The stepwise mechanism was found to hold also in the reaction of 3-phenylpropylsulfamate ester catalyzed by Rh2(S-nap)4. Furthermore, the diradical intermediate also constitutes the starting point for competition steps involving enantioselectivity, which is determined by the C-N formation open-shell singlet transition state. This mechanistic proposal is supported by the calculated enantiomeric excess (94.2% ee) with the absolute stereochemistry of the product as R, in good agreement with the experimental results (92.0% ee).
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Hyperproduction of mucin in the nasal epithelium is an important feature of nasal inflammatory diseases. We investigated the mechanism of lipopolysaccharides (LPS) involvement in mucin 5 subtype AC (MUC5AC) expression in human nasal epithelial cells. The primary human nasal epithelial cells were cultured in vitro, which were treated with LPS (10 nM/ml or 1 µM/ml) for 12 and 24 h. LPS-induced MUC5AC protein was determined in nasal epithelial cells. The levels of nuclear factor kappa B p65 (NF-κBp65) and its inhibitor kappa Bα (IκBα) protein were also detected, and interleukin-1ß (IL-1ß) mRNA was detected by real-time PCR. LPS up-regulated MUC5AC protein in human nasal epithelial cells, and we determined that the up-regulation of MUC5AC expression was due to a time- and dose-dependent degradation of IκBα protein, which resulted in the increase of NF-κBp65 nuclear translocation. Subsequently, we also determined that LPS can induce IL-1ß mRNA in a time- and dose-dependent manner. These data show that LPS treatment activated NF-κB by promoting the degradation of IκBα and the nuclear localization of NF-κBp65, which induced MUC5AC overproduction.
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Lipopolisacáridos/farmacología , Mucina 5AC/metabolismo , Mucosa Nasal/metabolismo , Adolescente , Adulto , Western Blotting , Células Cultivadas , Humanos , Inmunohistoquímica , Interleucina-1beta/metabolismo , Persona de Mediana Edad , FN-kappa B/metabolismo , Adulto JovenRESUMEN
The mechanism and intermediates of hydroalkylation of aryl alkynes via C(sp(3))-H activation through a platinum(II)-centered catalyst are investigated with density functional theory at the B3LYP/[6-31G(d) for H, O, C; 6-31+G(d,p) for F, Cl; SDD for Pt] level of theory. Solvent effects on reactions were explored using calculations that included a polarizable continuum model for the solvent (THF). Free energy diagrams for three suggested mechanisms were computed: (a) one that leads to formation of a Pt(II) vinyl carbenoid (Mechanism A), (b) another where the transition state implies a directed 1,4-hydrogen shift (Mechanism B), and (c) one with a Pt-aided 1,4-hydrogen migration (Mechanism C). Results suggest that the insertion reaction pathway of Mechanism A is reasonable. Through 4,5-hydrogen transfer, the Pt(II) vinyl carbenoid is formed. Thus, the stepwise insertion mechanism is favored while the electrocyclization mechanism is implausible. Electron-withdrawing/electron-donating groups substituted at the phenyl and benzyl sp(3) C atoms slightly change the thermodynamic properties of the first half of Mechanism A, but electronic effects cause a substantial shift in relative energies for the second half of Mechanism A. The rate-limiting step can be varied between the 4,5-hydrogen shift process and the 1,5-hydrogen shift step by altering electron-withdrawing/electron-donating groups on the benzyl C atom. Additionally, NBO and AIM analyses are applied to further investigate electronic structure changes during the mechanism.
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Alquinos/química , Indenos/síntesis química , Platino (Metal)/química , Teoría Cuántica , Alquilación , Catálisis , Ciclización , Indenos/química , Estructura Molecular , TermodinámicaRESUMEN
Air pollution is associated with increased morbidity and mortality and with cell death at a cellular level. However, the exact mechanism of particulate matter-induced cell death remains to be elucidated. The aim of the present in vitro study using human alveolar epithelial cells (A549) was to determine the cell death pathway(s) induced by black carbon (BC) and ozone oxidized-black carbon (O-BC). BC and O-BC induced A549 cell death and the cytotoxic effect was dose-dependent. Cell death was significantly abrogated by inhibitor of receptor protein interacting kinase 1 (RIPK1) but only mildly inhibited by apoptosis inhibitor and RIPK3. BC- and O-BC-treated cells showed RIPK1 and RIPK3 protein overexpression and high phosphorylated levels of these proteins, as well as detectable levels of caspase-8 active form. BC- and O-BC-triggered cell death was also fully rescued in A549 cells that under-expressed RIPK1 with RIPK1 siRNA. Our results indicated that BC and O-BC could induce cell death through a multitude of pathways including apoptotic and necroptotic pathways and that RIPK1 is the upstream signal protein of these cell death pathways, with an important role in the regulation of BC-induced cell death.
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Apoptosis , Proteína Serina-Treonina Quinasas de Interacción con Receptores , Hollín/efectos adversos , Células A549 , Apoptosis/genética , Muerte Celular , Humanos , Proteína Serina-Treonina Quinasas de Interacción con Receptores/genética , Proteína Serina-Treonina Quinasas de Interacción con Receptores/metabolismoRESUMEN
Design and construction of a matrix with specific adsorption on the target compounds can effectively reduce the detection limit of surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF MS) analysis. Sulfonic acid functionalized hierarchical porous covalent organic frameworks (H-COF-SO3H) was synthesized by defect-structure and post-modification method, and then used as matrix and adsorbent for the determination of quaternary ammonium herbicides paraquat (PQ) and diquat (DQ). N2 adsorption-desorption experiments confirmed that H-COF-SO3H possesses hierarchical porosity with pore widths concentrated at 1.3,1.5, and 2.8â¯nm. The strong UV absorption at 200-450â¯nm and good thermal stability made H-COF-SO3H being a promising matrix without background interference. H-COF-SO3H can efficiently enrich PQ and DQ via electrostatic attraction, and the key role of -SO3H group on specific adsorption was confirmed by density functional theory (DFT) calculations. The limits of detection (LODs) for PQ and DQ with H-COF-SO3H enrichment were 0.5 and 0.1â¯ng·mL-1, respectively, which were 20 and 60 times higher than those without H-COF-SO3H enrichment, respectively. The spiked recoveries of PQ and DQ for the three food samples were 92.0-113.2% and 80.1-102.6% with RSDs of 2.2-9.2% and 2.0-8.7%, respectively. This work provides an analyte-oriented approach for fabricating SALDI-TOF MS matrix.
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Diquat , Estructuras Metalorgánicas , Paraquat , Porosidad , Ácidos SulfónicosRESUMEN
A new route to synthesize a covalent interaction-based molecularly imprinted polymer (MIP) material for 3-chloro-1,2-propanediol (3-MCPD) inside the nanopores of anodic alumina oxide (AAO) is presented. A series of adsorption experiments showed MIP had good extraction capacity and selectivity for 3-MCPD. In order to evaluate the usability of the MIP nanotubes membrane, a method combining AAO@MIP membrane extraction with gas chromatography - mass spectrometry (GC-MS) detection was developed for determination of chloropropanols. The limits of detection for the proposed method were 0.072 and 0.13⯵g·L-1, respectively, for 3-MCPD and 1,3-DCP. The average recoveries of 3-MCPD and 1,3-DCP spiked oil samples at three concentrations (0.01, 0.05 and 0.1â¯mg·kg-1) were in the range of 75.6-101.0% with a RSD of 3.3-8.4%, indicating the method would be suitable for determination of chloropropanols in vegetable oils.
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Óxido de Aluminio/química , Cromatografía de Gases y Espectrometría de Masas , Impresión Molecular , Nanotubos/química , Aceites de Plantas/química , alfa-Clorhidrina/análisis , Adsorción , Límite de Detección , Nanoporos/ultraestructura , Óxidos/química , Polímeros/química , Extracción en Fase SólidaRESUMEN
Chronic prenatal hypoxia is a damaging to fetal development and may have various consequences, including hearing loss. Connexin 26 (Cx26) is one of the major protein subunits required for gap junction formation, and has an important role in maintaining homeostasis in the cochlea and normal hearing. Cx26 mutation and expression abnormality are closely associated with inherited nonsyndromic deafness, but the association between Cx26 and prenatal hypoxia is less established. The present study aimed to examine Cx26 expression and aberrant methylation the Cx26 promoter region in the cochlea from rats exposed to chronic prenatal hypoxia. Hematoxylin and eosin staining demonstrated that the number of hair cells in the organ of Corti were less in the hypoxia group. Reverse transcriptionquantitative polymerase chain reaction and western blot analysis revealed that protein and mRNA levels of Cx26 were decreased in the hypoxia group compared with the control group. Further bisulfite sequencing analysis revealed that prenatal hypoxia significantly increased the methylation status of the promoter region of the Cx26 gene. These results demonstrate that chronic prenatal hypoxia caused hearing impairment, and suggest that promoter region hypermethylation and expression downregulation of Cx26 underlie the mechanism of action.
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Cóclea/metabolismo , Conexina 26/genética , Metilación de ADN/genética , Hipoxia/genética , Animales , Cóclea/crecimiento & desarrollo , Uniones Comunicantes/genética , Regulación del Desarrollo de la Expresión Génica/genética , Células Ciliadas Auditivas/metabolismo , Células Ciliadas Auditivas/patología , Humanos , Organogénesis/genética , Regiones Promotoras Genéticas , RatasRESUMEN
Particulate matter (PM) air pollution has been associated with an increase in the incidence of chronic allergic diseases; however, the mechanisms underlying the effect of exposure to natural ambient air pollution in chronic allergic diseases have not been fully elucidated. In the present study, we aimed to investigate the cellular responses induced by exposure to natural ambient air pollution, employing a mouse model of chronic allergy. The results indicated that exposure to ambient air pollution significantly increased the number of eosinophils in the nasal mucosa. The modulation of gene expression profile identified a set of regulated genes, and the Triggering Receptor Expressed on Myeloid cells1(TREM1) signaling canonical pathway was increased after exposure to ambient air pollution. In vitro, PM2.5 increased Nucleotide-binding oligomerization domain-containing protein 1 (Nod1) and nuclear factor (NF)-κB signaling pathway activation in A549 and HEK293 cell cultures. These results suggest a novel mechanism by which, PM2.5 in ambient air pollution may stimulate the innate immune system through the PM2.5-Nod1-NF-κB axis in chronic allergic disease.
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Hipersensibilidad/genética , Material Particulado/efectos adversos , Células A549 , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Animales , Exposición a Riesgos Ambientales/análisis , Monitoreo del Ambiente/métodos , Eosinófilos/metabolismo , Femenino , Células HEK293 , Humanos , Hipersensibilidad/metabolismo , Ratones , Ratones Endogámicos BALB C , FN-kappa B/metabolismo , Mucosa Nasal/metabolismo , Proteína Adaptadora de Señalización NOD1/genética , Proteína Adaptadora de Señalización NOD1/metabolismo , Material Particulado/análisis , Transcriptoma/genética , Receptor Activador Expresado en Células Mieloides 1/genética , Receptor Activador Expresado en Células Mieloides 1/metabolismoRESUMEN
A robust primitive diamond-type topology 3-D metal-organic framework (MOF) of {[Cd4(hbhdpy)2(bdc)3(DMA)2]·(H2O)4}n (1, DMA = N,N-dimethylacetamide) was constructed from the planar secondary building units of the dinuclear cadmium clusters, Cd2(µ2-O)2, and two linear organic linkers of the new multidentate Schiff base of 4-(2-hydroxy-3-methoxy-benzyli-denehydrazino-carbonyl)-N-pyridin-4-yl-benzamide (Hhbhdpy) through the solvothermal reaction. 1 presents a 2-fold interpenetrating network along with confined narrow channels and rich acylamide groups as well as potential metal open sites for excellent selective CO2 uptake over CH4/N2 and high luminescent response for 2,4,6-trinitrophenol (TNP) in DMA solution under ambient conditions. With 2-amino-1,4-dicarboxy-benzene (H2bdc-NH2) replacing H2bdc, an amine-functionalized MOF of {[Cd4(hbhdpy)2(bdc-NH2)3 (DMA)2]·(H2O)4}n (1-NH2) as an isomorphism of 1, was synthesized under the same reaction conditions. Compared with 1, the corresponding bifunctional features of 1-NH2 is more obvious. To the best of our knowledge, it is the first reported interpenetrating Cd-MOFs with highly sensitive luminescence response for TNP molecules combined with excellent selectivity for CO2/N2 and CO2/CH4.
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In this paper, a method for the synthesis of ractopamine molecularly imprinted polymers (MIPs) nanotube membranes on anodic alumina oxide (AAO) nanopore surface by atom transfer radical polymerization (ATRP) was presented, in which methacrylic acid (MAA) was selected as functional monomer with a polymerization rate of 1:6 between ractopamine and MAA by the computational investigations. The morphology of MIPs nanotube membranes characterized by scanning electron microscope (SEM) suggested a well growth in the AAO nanopore surface. A series of adsorption experiments revealed that the MIPs nanotube membranes showed better extraction capacity and good selectivity for ractopamine and its analogues than that of non-imprinted polymers (NIPs) nanotube membranes. In order to evaluate the usability of the MIPs nanotube membranes, a methodology by combining MIPs nanotube membranes extraction couple with high performance liquid chromatography (HPLC) detection for the determination of ß2-agonists in complex samples was developed. The linear ranges were 10-1000 µg/L for ractopamine, 100-1000 µg/L for clenbuterol, epinephrine and dopamine, and 200-1000 µg/L for terbutaline. The detection limits were within the range of 0.074-0.25 µg/L and the RSDs (n=3) were from 2.8% to 4.3%. The method was successfully applied to the analysis of ß2-agonists in spiked real samples, The recoveries of all the ß2-agonists at the two concentration levels were found to be within the range of 86.3-97.0% and 82.8-95.7%, respectively. The RSDs were within 2.7-5.7%. The results demonstrated that the proposed method is very suitable for the determination of ß2-agonists in pork samples.
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Agonistas Adrenérgicos beta/análisis , Análisis de los Alimentos/métodos , Carne/análisis , Nanoporos , Polímeros/síntesis química , Adsorción , Animales , Cromatografía Líquida de Alta Presión , Clenbuterol/análisis , Metacrilatos/química , Impresión Molecular , Fenetilaminas/análisis , PorcinosRESUMEN
A porous sludge-derived char was prepared by a new one-step pyrolytic process with citric acid-ZnCl2 mixed fabricating-pore agents. The sludge-derived char was confirmed to be a hierarchically porous hybrid adsorbent containing-elemental carbon, -highly carbonized organic species and -inorganic ash with a great surface area of 792.4m(2)g(-1). It was used as a carbon-based hybrid adsorbent for four benzene derivatives including 4-chlorophenol, phenol, benzoic acid and 4-hydroxylbenzoic acid in aqueous solution. Results showed that their sorption isotherms were nonlinear at low concentrations and linear at high concentrations. The sorption performance could be described by a multiple sorption model (QT=QA+KPCe). The order of these partition sorption coefficients (KP) of these benzene derivatives was consistent with their octanol-water partition coefficients (logKow), but those saturated amounts (QA) were inconsistent with their logKow. The inconstancy was found to be considerably dependent on the preferential interaction of benzoic acid with SiO2 in the sludge-derived char. Quantum theoretical calculation confirmed that the preferential interaction was attributed to the formation of hydrogen bonds (1.61 and 1.69Å) and new Si-O bonds (1.83 and 1.87Å) between the carboxyl of benzoic acid and the SiO2 surface in the sorption process.
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Derivados del Benceno/química , Aguas del Alcantarillado , Contaminantes Químicos del Agua/química , Adsorción , Carbono/química , Cloruros/química , Ácido Cítrico/química , Residuos Industriales , Porosidad , Aguas del Alcantarillado/química , Soluciones , Eliminación de Residuos Líquidos , Compuestos de Zinc/químicaRESUMEN
We systematically studied the structural, energetic and electronic properties of zigzag boron nitride nanotubes (BNNTs) functionalized by a class of substituted carbenes (CR(2)) where R = H, F, Cl, CH(3), CN and NO(2) on different absorption sites using density functional theory. For R = H, F and Cl, the open structure is preferred with a BNNT sidewall bond cleavage, while for R = CH(3) and CN, a competition between the open and closed cyclopropane-like three-membered ring (3MR) structure occurs. Interestingly, for R = NO(2) we find a novel double five-membered ring (5MR) structure with high reaction stability. This new structure cannot be found in BNNTs' alternative carbon nanotubes (CNTs). In addition, the electronic properties of BNNTs functionalized with carbenes are hardly changed for R = H, F, Cl, CH(3) and CN, but are significantly affected when R = NO(2) due to the heterocyclic double 5MR structure.