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Tailoring the hydrophobicity of supramolecular assembly building blocks enables the fabrication of well-defined functional materials. However, the selection of building blocks used in the assembly of metal-phenolic networks (MPNs), an emerging supramolecular assembly platform for particle engineering, has been essentially limited to hydrophilic molecules. Herein, we synthesized and applied biscatechol-functionalized hydrophobic polymers (poly(methyl acrylate) (PMA) and poly(butyl acrylate) (PBA)) as building blocks to engineer MPN particle systems (particles and capsules). Our method allowed control over the shell thickness (e.g., between 10 and 21â nm), stiffness (e.g., from 10 to 126â mN m-1 ), and permeability (e.g., 28-72 % capsules were permeable to 500â kDa fluorescein isothiocyanate-dextran) of the MPN capsules by selection of the hydrophobic polymer building blocks (PMA or PBA) and by controlling the polymer concentration in the MPN assembly solution (0.25-2.0â mM) without additional/engineered assembly processes. Molecular dynamics simulations provided insights into the structural states of the hydrophobic building blocks during assembly and mechanism of film formation. Furthermore, the hydrophobic MPNs facilitated the preparation of fluorescent-labeled and bioactive capsules through postfunctionalization and also particle-cell association engineering by controlling the hydrophobicity of the building blocks. Engineering MPN particle systems via building block hydrophobicity is expected to expand their use.
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Small molecules, including therapeutic drugs and tracer molecules, play a vital role in biological processing, disease treatment and diagnosis, and have inspired various nanobiotechnology approaches to realize their biological function, particularly in drug delivery. Desirable features of a delivery system for functional small molecules (FSMs) include high biocompatibility, high loading capacity, and simple manufacturing processes, without the need for chemical modification of the FSM itself. Herein, we report a simple and versatile approach, based on metal-phenolic-mediated assembly, for assembling FSMs into nanoparticles (i.e., FSM-MPN NPs) under aqueous and ambient conditions. We demonstrate loading of anticancer drugs, latency reversal agents, and fluorophores at up to ~80 % that is mostly facilitated by π and hydrophobic interactions between the FSM and nanoparticle components. Secondary nanoparticle engineering involving coating with a polyphenol-antibody thin film or sequential co-loading of multiple FSMs enables cancer cell targeting and combination delivery, respectively. Incorporating fluorophores into FSM-MPN NPs enables the visualization of biodistribution at different time points, revealing that most of these NPs are retained in the kidney and heart 24â h post intravenous administration. This work provides a viable pathway for the rational design of small molecule nanoparticle delivery platforms for diverse biological applications.
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Nanopartículas , Distribución Tisular , Nanopartículas/química , Sistemas de Liberación de Medicamentos , Fenoles , Polifenoles , MetalesRESUMEN
Crystalline metal-organic frameworks (MOFs) have garnered extensive attention owing to their highly ordered porous structure and physicochemical properties. However, their practical application often requires their integration with various substrates, which is challenging because of their weakly adhesive nature and the diversity of substrates that exhibit different properties. Herein, we report the use of amorphous metal-phenolic network coatings to facilitate the growth of crystalline MOF coatings on various particle and planar substrates. Crystalline MOFs with different metal ions and morphologies were successfully deposited on substrates (13 types) of varying sizes, shapes, and surface chemistries. Furthermore, the physicochemical properties of the coated crystalline MOFs (e.g., composition, thickness) could be tuned using different synthesis conditions. The engineered MOF-coated membranes demonstrated excellent liquid and gas separation performance, exhibiting a high H2 permeance of 63200â GPU and a H2/CH4 selectivity of 10.19, likely attributable to the thin nature of the coating (~180â nm). Considering the vast array of MOFs available (>90,000) and the diversity of substrates, this work is expected to pave the way for creating a wide range of MOF composites and coatings with potential applications in diverse fields.
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In order to clarify the individual role of freezing and frozen storage on the quality of fish, fillets of large-mouth bass (Micropterus salmoides) were subjected to different freezing rates (freezing with -18 °C (A), -60 °C (B), and -60 °C with forced air circulation at 2 m/s (C), respectively) followed by frozen storage at -18 °C for 30 and 90 days. Another two groups were frozen at -60 °C, followed by storage at -40 °C (D) and -60 °C (E), respectively. Results showed that water-holding and TVBN were mainly affected by storage time. No significant changes were found in free thiol content among treatments. A greater freezing rate and lower storage temperature generally led to lower TBARS. GC × GC-TOFMS revealed a total of 66 volatile compounds, which were related to lipid oxidation. PLS-DA showed that fresh samples were separated from the frozen-thawed ones, and fillets in groups D and E were relatively close to fresh fillets in the composition of oxidation-related volatiles. In conclusion, freezing rate and storage temperature had a significant impact on lipid oxidation and protein denaturation in the fillets of large-mouth bass, while protein oxidation was more affected by freezing rate.
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Lubina , Animales , Congelación , Temperatura , Lípidos , Boca , Almacenamiento de Alimentos/métodosRESUMEN
Irradiation can be used for the preservation of chickpea protein as it can destroy microorganisms, bacteria, virus, or insects that might be present. However, irradiation may provoke oxidative stress, and therefore modify the functionality and nutritional value of chickpea protein. In order to study the effects of irradiation on the physicochemical properties and digestion behaviour of chickpea protein, chickpea protein concentrate (CPC) was treated with electron beam irradiation (EBI) at doses of 5, 10, 15, and 20 kGy. After irradiation, protein solubility first increased at 10 kGy and 15 kGy, and then decreased at the higher dose of 20 kGy. This was supported by SDS-PAGE, where the intensity of major protein bands first increased and then decreased. Increased doses of EBI generally led to greater oxidative modification of proteins in CPC, indicated by reduced sulfhydryls and increased carbonyls. In addition, the protein structure was modified by EBI as shown by Fourier transform infrared spectroscopy analysis, where α-helix generally decreased, and ß-sheet increased. Although the protein digestibility was not significantly affected by EBI, the peptidomic analysis of the digests revealed significant differences among CPC irradiated with varying doses. A total of 337 peptides were identified from CPC irradiated with 0 kGy, 10 kGy, and 20 kGy, with 18 overlapping peptides and 60, 29, and 40 peptides specific to the groups of 0, 10, and 20 kGy respectively. Theoretical calculation showed that the distribution of peptide length, hydrophobicity, net charge, and C-terminal residues were affected by irradiation. The 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity showed a marginal decrease with an increasing dose of irradiation. In conclusion, EBI led to oxidative modification and structural changes in chickpea protein, which subsequently affected the physicochemical properties of peptides obtained from in-vitro digestion of CPC, despite similar digestibility.
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Cicer , Electrones , Electroforesis en Gel de Poliacrilamida , Valor Nutritivo , Estrés OxidativoRESUMEN
Coordination assembly offers a versatile means to developing advanced materials for various applications. However, current strategies for assembling metal-organic networks into nanoparticles (NPs) often face challenges such as the use of toxic organic solvents, cytotoxicity because of synthetic organic ligands, and complex synthesis procedures. Herein, we directly assemble metal-organic networks into NPs using metal ions and polyphenols (i.e., metal-phenolic networks (MPNs)) in aqueous solutions without templating or seeding agents. We demonstrate the role of buffers (e.g., phosphate buffer) in governing NP formation and the engineering of the NP physicochemical properties (e.g., tunable sizes from 50 to 270â nm) by altering the assembly conditions. A library of MPN NPs is prepared using natural polyphenols and various metal ions. Diverse functional cargos, including anticancer drugs and proteins with different molecular weights and isoelectric points, are readily loaded within the NPs for various applications (e.g., biocatalysis, therapeutic delivery) by direct mixing, without surface modification, owing to the strong affinity of polyphenols to various guest molecules. This study provides insights into the assembly mechanism of metal-organic complexes into NPs and offers a simple strategy to engineer nanosized materials with desired properties for diverse biotechnological applications.
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Nanopartículas del Metal , Nanopartículas , Fenoles , Polifenoles/química , Nanopartículas/química , Metales/química , AguaRESUMEN
Flexible metal-organic materials are of growing interest owing to their ability to undergo reversible structural transformations under external stimuli. Here, we report flexible metal-phenolic networks (MPNs) featuring stimuli-responsive behavior to diverse solute guests. The competitive coordination of metal ions to phenolic ligands of multiple coordination sites and solute guests (e.g., glucose) primarily determines the responsive behavior of the MPNs, as revealed experimentally and computationally. Glucose molecules can be embedded into the dynamic MPNs upon mixing, leading to the reconfiguration of the metal-organic networks and thus changes in their physicochemical properties for targeting applications. This study expands the library of stimuli-responsive flexible metal-organic materials and the understanding of intermolecular interactions between metal-organic materials and solute guests, which is essential for the rational design of responsive materials for various applications.
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Supramolecular assembly affords the development of a wide range of polypeptide-based biomaterials for drug delivery and nanomedicine. However, there remains a need to develop a platform for the rapid synthesis and study of diverse polypeptide-based materials without the need for employing complex chemistries. Herein, we develop a versatile strategy for creating polypeptide-based materials using polyphenols that display multiple synergistic cross-linking interactions with different polypeptide side groups. We evaluated the diverse interactions operating within these polypeptide-polyphenol networks via binding affinity, thermodynamics, and molecular docking studies and found that positively charged polypeptides (Ka of â¼2 × 104 M-1) and polyproline (Ka of â¼2 × 106 M-1) exhibited stronger interactions with polyphenols than other amino acids (Ka of â¼2 × 103 M-1). Free-standing particles (capsules) were obtained from different homopolypeptides using a template-mediated strategy. The properties of the capsules varied with the homopolypeptide used, for example, positively charged polypeptides produced thicker shell walls (120 nm) with reduced permeability and involved multiple interactions (i.e., electrostatic and hydrogen), whereas uncharged polypeptides generated thinner (10 nm) and more permeable shell walls due to the dominant hydrophobic interactions. Polyarginine imparted cell penetration and endosomal escape properties to the polyarginine-tannic acid capsules, enabling enhanced delivery of the drug doxorubicin (2.5 times higher intracellular fluorescence after 24 h) and a corresponding higher cell death in vitro when compared with polyproline-tannic acid capsules. The ability to readily complex polyphenols with different types of polypeptides highlights that a wide range of functional materials can be generated for various applications.
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Péptidos , Polifenoles , Cápsulas/química , Sistemas de Liberación de Medicamentos , Simulación del Acoplamiento Molecular , Péptidos/química , Taninos/químicaRESUMEN
Coordination states of metal-organic materials are known to dictate their physicochemical properties and applications in various fields. However, understanding and controlling coordination sites in metal-organic systems is challenging. Herein, we report the synthesis of site-selective coordinated metal-phenolic networks (MPNs) using flavonoids as coordination modulators. The site-selective coordination was systematically investigated experimentally and computationally using ligands with one, two, and multiple different coordination sites. Tuning the multimodal Fe coordination with catechol, carbonyl, and hydroxyl groups within the MPNs enabled the facile engineering of diverse physicochemical properties including size, selective permeability (20-2000â kDa), and pH-dependent degradability. This study expands our understanding of metal-phenolic chemistry and provides new routes for the rational design of structurally tailorable coordination-based materials.
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Metales , Fenoles , Ligandos , Metales/química , Fenoles/químicaRESUMEN
In order to investigate the effects of multi-frequency ultrasound-assisted immersion freezing (MUIF) on the meat quality of Macrobrachium rosenbergii, tail meat was subjected to different MUIF treatments respectively, namely 20 + 40 kHz (MUIF-20 + 40), 20 + 60 kHz (MUIF-20 + 60), 40 + 60 kHz (MUIF-40 + 60) and 20 + 40 + 60 kHz (MUIF-20 + 40 + 60), and the immersion freezing (IF) as control. Results showed that average diameter of ice crystals was 28 µm in IF, and that was only 8 µm in MUIF-20 + 40 + 60. When compared to IF, MUIF alleviated oxidative deterioration of lipids and proteins, but only at higher ultrasound frequency (MUIF-40 + 60; MUIF-20 + 40 + 60). Carbonyl content of MUIF-20 + 40 + 60 was only 40% of that in IF. Similarly, protein denaturation was inhibited in MUIF (except for MUIF-20 + 40). Transmission electron microscopy showed greater distortion of the ultrastructural components in IF, MUIF-40 + 60, and MUIF-20 + 40 + 60, suggested by bended Z-line. In conclusion, MUIF can be an effective strategy to mitigate mechanical damage and protein deterioration in the meat of Macrobrachium rosenbergii.
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OBJECTIVE: The purpose of this article was to investigate the value of combined MRI, enhanced CT and 18F-FDG PET/CT in the diagnosis of recurrence and metastasis after surgery for ovarian cancer. METHODS: Ninety-five ovarian cancer patients were selected as the study subjects, all of them underwent surgical treatment, and MRI, enhanced CT and 18F-FDG PET/CT were performed on all of them in the postoperative follow-up, and the pathological results after the second operation were used as the diagnostic "gold standard". The diagnostic value (sensitivity, specificity, accuracy, negative predictive value and positive predictive value) of the three examination methods alone or in combination for the diagnosis of postoperative recurrence and metastasis of ovarian cancer was compared, and the detection rate was calculated when the lesion was the unit of study, so as to compare the efficacy of the three methods in the diagnosis of postoperative recurrent metastatic lesions of ovarian cancer. RESULTS: The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of the combined group were higher than those of MRI and enhanced CT for recurrence and metastasis of ovarian cancer after surgery, and the specificity, accuracy and positive predictive value of the combined group were higher than those of the 18F-FDG PET/CT group, and those of the 18F-FDG PET/CT group were higher than those of the enhanced CT group (all P < 0.05). When the postoperative recurrent metastatic lesions of ovarian cancer were used as the study unit, the detection rate of lesions in the combined group was higher than that of the three examinations detected individually, and the detection rate of lesions in 18F-FDG PET/CT was higher than that of enhanced CT and MRI (P < 0.05). CONCLUSION: The combination of MRI, enhanced CT and 18F-FDG PET/CT can accurately diagnose recurrence and metastasis of ovarian cancer after surgery, detect recurrent metastatic lesions as early as possible, and improve patients' prognosis.
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The purpose of this study was to determine the effect of pre-rigor salting on the quality characteristics of surimi gels prepared from snakehead fish muscle. Pre-rigor and post-rigor muscle were mixed with 0.3% or 3% NaCl (w/w) and made into surimi gels, respectively. Results showed that pre-rigor muscle had a higher content of ATP, longer sarcomere, higher pH and greater protein solubility. Metabolic profile suggested that pre-rigor muscle had higher content (a 28-fold increase) of antioxidants such as butyryl-l-carnitine. Transmission electron microscopy showed more damage of mitochondria in post-rigor muscle. Surimi paste from pre-rigor meat chopped with 3% NaCl generally showed greater radical scavenging ability and had higher content of free sulfhydryl. Surimi gel made from pre-rigor muscle salted with 3% NaCl showed a larger gel strength (3.18 kg*mm vs. 2.22 kg*mm) and better water-holding (86% vs. 80%) than that of post-rigor group. Based on these findings, we hypothesized that: In addition to other factors such as pH, degree of denaturation, etc., less protein oxidation in pre-rigor salted surimi also contributes to the improved gel properties.
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Productos Pesqueros , Proteínas de Peces , Geles , Oxidación-Reducción , Animales , Geles/química , Productos Pesqueros/análisis , Proteínas de Peces/química , Cloruro de Sodio/química , Cloruro de Sodio/análisis , Peces , Manipulación de Alimentos , Agua/química , Perciformes/metabolismo , Concentración de Iones de HidrógenoRESUMEN
Fluorinated motifs are promising for the engineering of repellent coatings, however, a fundamental understanding of how to effectively bind these motifs to various substrates is required to improve their stability in different use scenarios. Herein, the binding of fluorinated polyhedral oligomeric silsesquioxanes (POSS) using a cyanoacrylate glue (binder) is computationally and experimentally evaluated. The composite POSS-binder coatings display ultralow surface energy (≈10 mJ m-2 ), while still having large surface adhesions to substrates (300-400 nN), highlighting that super-repellent coatings (contact angles >150°) can be readily generated with this composite approach. Importantly, the coatings show super-repellency to both corrosive liquids (e.g., 98 wt% H2 SO4 ) and ultralow surface tension liquids (e.g., alcohols), with ultralow roll-off angles (<5°), and tunable resistance to liquid penetration. Additionally, these coatings demonstrate the potential in effective cargo loading and robust self-cleaning properties, where experimental datasets are correlated with both relevant theoretical predictions and systematic all-atom molecular dynamics simulations of the repellent coatings. This work not only holds promise for chemical shielding, heat transfer, and liquid manipulations but offers a facile yet robust pathway for engineering advanced coatings by effectively combining components for their mutually desired properties.
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In China, ambient fine particulate matter (PM2.5) causes a large health burden and raises specific concerns for policymakers. However, assessments of the health effects associated with air pollution from industrial land layouts remain inadequate. This study established a comprehensive assessment framework to quantify the health and economic impacts of PM2.5 exposure at different industrial geographical locations. This framework aims to optimize the spatial distribution of industrial emissions to achieve the lowest public health costs in Changsha, a representative industrial city in China. Health effects were estimated by applying the integrated exposure-response model and a long-range pollution dispersion model (CALPUFF). The value of statistical life (VSL) was used to monetize health outcomes. It was found that implementing an optimal industrial land layout can yield considerable social and financial benefits. Compared with the current industrial space layout, in 2030, the averted contribution by Changsha's industrial sector to PM2.5-related mortality and corresponding economic losses will be 60.8% and 0.69 billion US dollars (USD), respectively. The results of optimization analyses highlighted that population density and emission location are significant factors affecting the health burden. This method can identify the optimal geographical allocation of industrial land with minimal expected health and economic burden. These results will also provide policymakers with a measurable assessment of health risks related to industrial spatial planning and the associated health costs to enhance the effectiveness of efforts to improve air quality.
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Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , China , Ciudades , Material Particulado/análisis , Salud PúblicaRESUMEN
A novel restricted access molecularly imprinted polymers (RAMIPs) fiber was developed for solid-phase microextraction (SPME) of hesperetin and its metabolites in livers of live rats in vivo. Hesperetin as the template, N-isopropylacrylamide as the functional monomer, ethylene glycol dimethyl acrylate as the crosslinker, 2,2-azobisisobutyonnitrile as initiator and bovine serum albumin as the restricted access material were applied in the preparation process. Scanning electron microscopy and Fourier transform infrared spectroscopy were applied to characterize the polymers. The adsorption experiments indicated that RAMIPs-SPME fibers performed high selective recognition property to hesperetin. The selectivity experiment indicated that the adsorption capacity and selectivity of RAMIPs-SPME fibers to hesperetin was higher than that of quercetin, luteolin and baicalein. Macromolecules elimination test showed RAMIPs-SPME fibers could eliminate 94.80%-98.96% of macromolecules, which indicated that RAMIPs-SPME fibers can be used to extract analytes directly from complex biological samples. Furthermore, RAMIPs-SPME sampling combined to ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was applied to capture and identify hesperetin and its metabolites in rat livers in vivo. Finally, hesperetin-7-O-glucuronide, hesperetin-3'-O-glucuronide, eriodictyol and homoeriodictyol were identified as the metabolites of hesperetin. In comparison with the MIPs fibers, commercial PDMS and DVB fibers, RAMIPs-SPME fibers possessed better exclusion effect to macromolecules and higher selectivity to hesperetin and its metabolites. The results demonstrated that the prepared RAMIPs-SPME fiber were proven to be effective tool for the selective adsorption and enrichment of hesperetin and its metabolites from the complex biological fluids.
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Hesperidina/análisis , Impresión Molecular , Polímeros/química , Microextracción en Fase Sólida , Hesperidina/metabolismoRESUMEN
BACKGROUND: Most of the oral drugs have the properties of weak intestinal absorption and low bioavailability, which leads to little treatment to diseases. By nanotechnology, these drugs can be efficiently delivered to pass biological barriers and promote the cell uptake ability for the enhancement of the oral bioavailability. METHODS: The present work chose the prepared curcumin-loaded galactosylated albumin nanoparticles (Gal-BSA NPs) as the nano-drug samples to study the intestinal capacity and the oral bioavailability. RESULTS: The cell uptake assay showed that the Gal-BSA NPs could promote the internalization of more curcumin into the Caco-2 cells. Moreover, the cell uptake mechanism of Gal-BSA-Cur NPs depended on the clathrin-mediated endocytosis transport. The intestinal permeation assay using one Ussing chamber exhibited that the absorptive amounts of curcumin in Gal-BSA-Cur NPs group were 1.5-fold of pure curcumin group. Meanwhile, the permeation mechanism of Gal-BSA-Cur NPs across the intestine mainly depended on the passive transport. The pharmacokinetics study in vivo suggested that the oral bioavailability of Gal-BSA-Cur NPs was improved by 1.4-fold compared with pure curcumin. CONCLUSION: All results demonstrated that Gal-BSA NPs could improve the intestinal absorption capacity and oral bioavailability of curcumin through the double absorption mechanisms of the clathrin-mediated endocytosis and the passive transport.
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Curcumina/farmacocinética , Absorción Intestinal/efectos de los fármacos , Nanopartículas/administración & dosificación , Administración Oral , Animales , Disponibilidad Biológica , Células CACO-2 , Curcumina/administración & dosificación , Portadores de Fármacos/farmacocinética , Sistemas de Liberación de Medicamentos/métodos , Endocitosis/efectos de los fármacos , Galactosa/química , Humanos , Masculino , Nanopartículas/química , Ratas Sprague-Dawley , Albúmina Sérica Bovina/químicaRESUMEN
BACKGROUND: The main objective of this study was to develop novel BSA nanoparticles (BSA NPs) for improving the bioavailability of curcumin as an anticancer drug, and those BSA NPs were galactosylated for forming the curcumin-loaded galactosylated BSA nanoparticles (Gal-BSA-Cur NPs), thus enhancing their ability to target asialoglycoprotein receptor (ASGPR) overexpressed on hepatocellular carcinoma (HCC) cells. MATERIALS AND METHODS: Gal-BSA-Cur NPs were prepared by the desolvation method and showed a spherical shape and well distribution with the average particle size of 116.24 nm. RESULTS: In vitro drug release assay exhibited that Gal-BSA-Cur NPs had higher release rates and improved the curcumin solubility. Cell uptake studies confirmed that Gal-BSA-Cur NPs could selectively recognize receptors on the surface of HCC (HepG2) cells and improve internalization ability of drug compared with BSA NPs-loaded curcumin (BSA-Cur NPs), which might be due to high affinity to galactose. Further, the effects of Gal-BSA-Cur NPs were evaluated by cytotoxicity assay, crystal violet assay, cell apoptosis assay, and wound healing assay, respectively, which revealed that Gal-BSA-Cur NPs could inhibit HepG2 cells proliferation, induce cell apoptosis, and inhibit cell migration. CONCLUSION: Immunofluorescence staining has proved that the effects of Gal-BSA-Cur NPs related to the suppression of the nuclear factor κB-p65 (NF-κB-p65) expression in HepG2 cell nucleus. Therefore, these results indicate that novel Gal-BSA-Cur NPs are potential candidates for targeted curcumin delivery to HCC cells.
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Carcinoma Hepatocelular/tratamiento farmacológico , Movimiento Celular , Curcumina/uso terapéutico , Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos , Galactosa/química , Neoplasias Hepáticas/tratamiento farmacológico , Nanopartículas/química , Albúmina Sérica Bovina/química , Antineoplásicos/química , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Apoptosis/efectos de los fármacos , Unión Competitiva , Carcinoma Hepatocelular/patología , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Curcumina/síntesis química , Curcumina/química , Curcumina/farmacología , Portadores de Fármacos/síntesis química , Liberación de Fármacos , Endocitosis , Células Hep G2 , Humanos , Neoplasias Hepáticas/patología , Nanopartículas/ultraestructura , Tamaño de la Partícula , Espectroscopía Infrarroja por Transformada de Fourier , Factor de Transcripción ReIA/metabolismoRESUMEN
Both climate change and intensive human activities are thought to have contributed to the impairment of atmospheric visibility in Beijing. But the detailed processes involved and relative roles of human activities and climate change have not been quantified. Optical extinction of aerosols, the inverse of meteorological visibility is especially sensitive to fine particles <1.0⯵m. These submicron particles are considered more hazardous than larger ones in terms of cardiovascular and respiratory diseases. Here we used the aerosol optical extinction (inverse of visibility) as the indicator of submicron particles pollution to estimate its inter-annual variability from 1980 to 2015. Our results indicated that optical extinction experienced two different periods: a weakly increasing stage (1980-2005) and a rapidly increasing stage (2005-2015). We attributed the variations of optical extinction to the joint effects of human activities and climate change. Over the past 36â¯years, human activities played a leading role in the increase of optical extinction, with a positive contribution of 0.077â¯km-1/10â¯y. While under the effects of climate change, optical extinction firstly decreased by 0.035â¯km-1/10â¯y until 2005 and then increased by 0.087â¯km-1/10â¯y. Detailed analysis revealed that the abrupt change (around 2005) of optical extinction resulted from the trend reversals of climate change. We found since 2005 the decreasing trend by 0.58â¯m·s-1/10â¯y in wind speed, the growing trend at 8.69%/10â¯y in relative humidity and the declining trend by 2.72â¯hPa/10â¯y in atmospheric pressure have caused the rapid increase of optical extinction. In brief, the higher load of fine particles <1.0⯵m in Beijing in recent decades could be associated with both human activities and climate change. Particularly after 2005, the adverse climate change aggravated the situation of submicron particles pollution.
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Contaminación del Aire , Cambio Climático , Actividades Humanas , Beijing , Humanos , EsmogRESUMEN
In present study, novel magnetic molecularly imprinted polymers for hesperetin were successfully prepared by surface molecular imprinting method using functionalized Fe3O4 particles as the magnetic cores. Hesperetin as the template, N-Isopropylacrylamide as the functional monomer, ethylene glycol dimethyl acrylate as the crosslinker, 2,2-azobisisobutyonnitrile as initiator and acetonitrile-methanol (3:1, v/v) as the porogen were applied in the preparation process. Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscope, x-ray diffraction and vibrating sample magnetometry were applied to characterize the magnetic molecularly imprinted polymers. The adsorption experiments indicated that the magnetic molecularly imprinted polymers performed high selective recognition property to hesperetin. The selectivity experiment indicated that the adsorption capacity and selectivity of polymers to hesperetin was higher than that of luteolin, baicalein and ombuin. Furthermore, the magnetic molecularly imprinted polymers were employed as adsorbents for extraction and enrichment of hesperetin from the dried pericarp of Citrus reticulata Blanco. The recoveries of hesperetin in the dried pericarp of Citrus reticulata Blanco ranged from 90.5% to 96.9%. The linear range of 0.15-110.72⯵g/mL was obtained with correlation coefficient of greater than 0.9991. The limit of detection and quantification of the proposed method was 0.06⯵g/mL and 0.15⯵g/mL, respectively. Based on three replicate measurements, intra-day RSD was 0.71% and inter-day RSD was 2.31%. These results demonstrated that the prepared magnetic molecularly imprinted polymers were proven to be an effective material for the selective adsorption and enrichment of hesperetin from natural medicines, fruits and et al.
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Citrus/química , Frutas/química , Hesperidina/análisis , Nanopartículas de Magnetita/química , Impresión Molecular , Polímeros/química , Estructura Molecular , Tamaño de la Partícula , Propiedades de SuperficieRESUMEN
Based on our recent investigations on chalcone derivatives as AChE inhibitors, a series of ferulic acid (FA) tertiary amine derivatives similar to chalcone compounds were designed and synthesized. The results of bioactivity evaluation revealed that most of new synthesized compounds had comparable or more potent AChE inhibitory activity than the control drug Rivastigmine. The alteration of carbon chain linking tertiary amine groups and ferulic acid scaffold markedly influenced the inhibition activity against AChE. Among them the inhibitory activity of compound 6d (IC50: 0.71 ± 0.09 µmol/L) and 6e (IC50: 1.11 ± 0.17 µmol/L) was equal to 15-fold and 9-fold than that of Rivastigmine against AChE (IC50: 10.54 ± 0.86 µmol/L), respectively. Moreover, compound 6d shows the highest selectivity for AChE over butyrylcholinesterase(BuChE) (ratio: 18.3). The kinetic study suggested that compound 6d revealed a mixed-type inhibition against AChE. The result of molecular docking showed that compound 6d combines to AChE with three amino acid sites(Trp84, Tyr334 and Trp279), while combines to BuChE with two amino acid sites (Tyr67 and Gly66) in enzyme domains, respectively. Compound 6d might act as a potential agent for the treatment of Alzheimer's diseases (AD).