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1.
Artigo em Inglês | MEDLINE | ID: mdl-31676441

RESUMO

Maternal undernutrition during late gestation accelerates body fat mobilization to provide more energy for foetal growth and development, which unbalances metabolic homeostasis and results in serious lipid metabolism disorder. However, detailed regulatory mechanisms are poorly understood. Here, a sheep model was used to explore the regulatory role of PPARA/RXRA signalling in hepatic lipid metabolism in undernutrition based on RNA sequencing and cell experiments. KOG function classification showed that lipid transport and metabolism was markedly altered in an undernourished model. In detail, when compared with the controls, fatty acid transport and oxidation and triglyceride metabolism were up-regulated in an undernourished model, while fatty acid synthesis, steroid synthesis, and phospholipid metabolism were down-regulated. Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis demonstrated that PPARA/RXRA signalling pathway was altered. Moreover, PPARA signalling associated genes were positively correlated with hepatic non-esterified fatty acid (NEFA) levels, while retinol metabolism associated genes were negatively correlated with blood beta-hydroxybutyric acid (BHBA) levels. Results of primary hepatocytes showed that NEFAs could activate PPARA signalling and facilitate fatty acid oxidation (FAO) and ketogenesis, while BHBA could inhibit RXRA signalling and repress FAO and ketogenesis. Excessively accumulated NEFAs in hepatocytes promoted triglyceride synthesis. Furthermore, activation of PPARA/RXRA signalling by WY14643 and 9-cis-retinoic acid could enhance FAO and ketogenesis and reduce NEFAs accumulation and esterification. Our findings elucidate the regulatory mechanisms of NEFAs and BHBA on lipid metabolism as well as the potential role of the PPARA/RXRA signalling pathway in hepatic lipid metabolism, which may contribute to exploring new strategies to maintain lipid metabolic homeostasis in human beings.

2.
Small ; : e1903948, 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31657136

RESUMO

A comprehensive review on the five levels of hierarchical structures of silk materials and the correlation with macroscopic properties/performance of the silk materials, that is, the toughness, strain-stiffening, etc., is presented. It follows that the crystalline binding force turns out to be very important in the stabilization of silk materials, while the ß-crystallite networks or nanofibrils and the interactions among helical nanofibrils are two of the most essential structural elements, which to a large extent determine the macroscopic performance of various forms of silk materials. In this context, the characteristic structural factors such as the orientation, size, and density of ß-crystallites are very crucial. It is revealed that the formation of these structural elements is mainly controlled by the intermolecular nucleation of ß-crystallites. Consequently, the rational design and reconstruction of silk materials can be implemented by controlling the molecular nucleation via applying sheering force and seeding (i.e., with carbon nanotubes). In general, the knowledge of the correlation between hierarchical structures and performance provides an understanding of the structural reasons behind the fascinating behaviors of silk materials.

3.
Mar Drugs ; 17(9)2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31480659

RESUMO

In an effort to discover new bioactive anti-tumor lead compounds, a specific tyrosine phosphatase CDC25B and an Erb family receptor EGFR were selected as drug screening targets. This work led to the investigation of the soft coral-derived fungus Talaromyces verruculosus and identification of two new oligophenalenone dimers, verruculosins A-B (1-2), along with three known analogues, bacillisporin F (3), duclauxin (4), and xenoclauxin (5). Compound 1 was the first structure of the oligophenalenone dimer possessing a unique octacyclic skeleton. The detailed structures and absolute configurations of the new compounds were elucidated on the basis of spectroscopic data, X-ray crystallography, optical rotation, Electronic Circular Dichroism (ECD) analysis, and nuclear magnetic resonance (NMR) calculations. Among which, compounds 1, 3, and 5 exhibited modest inhibitory activity against CDC25B with IC50 values of 0.38 ± 0.03, 0.40 ± 0.02, and 0.26 ± 0.06 µM, respectively.

4.
Food Chem Toxicol ; 134: 110821, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31533060

RESUMO

The antifungal activity of plant essential oils (EOs) extracted by steam distillation from seven different species (Cinnamon, Anise, Clove, Citronella, Peppermint, Pepper, and Camphor) was investigated. Three common fungi were isolated from moldy wheat bread, which were identified as Aspergillus niger, A. oryzae, and A. ochraceus. The antifungal activity of anise, peppermint, clove, cinnamon, pepper, citronella, and camphor EOs from seven different spices was confirmed by agar diffusion assay against three fungi. Among all the EOs, the cinnamon EO showed the highest antifungal activity for all the fungi strains with the largest inhibition zone at the concentration of 800 mg/mL and lowest MIC ranging from 0.0625 to 0.125 mg/mL, followed by clove EO. The remaining EOs exerted moderate inhibitory effects. Further research indicated the substantial inhibitory activities of cinnamon and clove EOs on mycelial growth and spore germination in a dose-dependent manner. Further, the in vivo inhibitory activity of selected EOs on naturally infected bread demonstrated that cinnamon and clove EOs can as be used as natural antifungal agents.

5.
Cell Commun Signal ; 17(1): 117, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31500648

RESUMO

BACKGROUND: Cryptococcus neoformans (C. neoformans) is an encapsulated budding yeast that causes life-threatening meningoencephalitis in immunocompromised individuals, especially those with acquired immunodeficiency syndrome (AIDS). To cause meningoencephalitis, C. neoformans circulating in the bloodstream must first be arrested in the brain microvasculature. Neutrophils, the most abundant phagocytes in the bloodstream and the first leukocytes to be recruited to an infection site, can ingest C. neoformans. Little is known about how neutrophils interact with arrested fungal cells in the brain microvasculature. METHODS: A blood-brain barrier (BBB) in vitro model was established. The interactions between neutrophils adhering to brain endothelial cells and fungi were observed under a live cell imaging microscope. A flow cytometry assay was developed to explore the mechanisms. Immunofluorescence staining of brain tissues was utilized to validate the in vitro phenomena. RESULTS: Using real-time imaging, we observed that neutrophils adhered to a monolayer of mouse brain endothelial cells could expel ingested C. neoformans without lysis of the neutrophils or fungi in vitro, demonstrating nonlytic exocytosis of fungal cells from neutrophils. Furthermore, nonlytic exocytosis of C. neoformans from neutrophils was influenced by either the fungus (capsule and viability) or the neutrophil (phagosomal pH and actin polymerization). Moreover, nonlytic exocytosis of C. neoformans from neutrophils was recorded in brain tissue. CONCLUSION: These results highlight a novel function by which neutrophils extrude C. neoformans in the brain vasculature.

6.
ACS Appl Mater Interfaces ; 11(33): 30125-30136, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31368691

RESUMO

In this work, we demonstrate the principle of mesoscopic construction of silk fibroin (SF) hybrid materials, which endows the materials with new performance. In implementing this strategy, mediating molecules, wool keratin (WK) molecules, were adopted to in-line synthesize Au nanoparticles (WK@AuNPs), which further create the stable linkage of AuNPs with SF nanofibril networks via templated ß-crystallization. Fourier transform infrared spectroscopy, X-ray diffraction, and atomic force microscopy demonstrate that the mesoscopic hybrid network structure of the hybrid materials is different from neat SF materials, which gives rise to various new performances, that is, long-stable fluorescence emission. As the fluorescence emission can be characteristically annealed by Cu ions, therefore be adopted as the highly selective ion probes. Moreover, as WK@AuNPs are homogeneously connected to SF nanofibril networks, the carbonization of the materials leads to secondary hybrid materials of carbon-Au, where nano-sized Au particles are well distributed in carbonized mesoscopic conductive carbon networks. Such hybrid materials of carbon-Au can be further fabricated into electrochemical (i.e., dopamine) sensors, which are demonstrated to have excellent sensing performance.

7.
FASEB J ; 33(9): 9990-10004, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31167079

RESUMO

Undernutrition accelerates body fat mobilization to alleviate negative energy balance, which disrupts homeostasis of lipid metabolism in maternal liver. However, little is known about its effect on fetal metabolism and development. Here, a sheep model was used to explore whether maternal undernutrition induces fetal lipid metabolism disorder and further inhibits fetal hepatic development. Twenty pregnant ewes were either fed normally or restricted to 30% level for 15 d, after which fetal hepatic samples were collected to conduct transcriptome, metabolome, histomorphology, and biochemical analysis. Results showed that maternal undernutrition altered the general transcriptome profile and metabolic mode in fetal liver. Fatty acid oxidation and ketogenesis were enhanced in fetal livers of undernourished ewes, which might be promoted by the activated peroxisome proliferator-activated receptor α signaling pathway, whereas cholesterol, steroid, and fatty acid synthesis were repressed. Maternal undernutrition increased triglyceride synthesis, decreased triglyceride degradation, and inhibited phospholipid degradation and synthesis in fetal liver. In addition, our data revealed that maternal undernutrition extremely inhibited DNA replication, cell cycle progression, and antiapoptosis and broke the balance between cell proliferation and apoptosis in fetal liver, indicating that maternal undernutrition affects the growth and development of fetal liver. Generally, these findings provide evidence that maternal undernutrition during pregnancy disturbs fetal lipid metabolism and inhibits fetal hepatic development in sheep, which greatly contribute to the further study of fetal metabolism and development in human beings.-Xue, Y., Guo, C., Hu, F., Zhu, W., Mao, S. Maternal undernutrition induces fetal hepatic lipid metabolism disorder and affects the development of fetal liver in a sheep model.

8.
Zhongguo Yi Liao Qi Xie Za Zhi ; 43(3): 217-219, 2019 May 30.
Artigo em Chinês | MEDLINE | ID: mdl-31184083

RESUMO

This article summarizes the common problems in registration and supervision testing of infrared therapy equipment, combines YY 0306-2008 Particular requirements for the safety of heat radiation therapy equipment, GB 9706.1-2007 Medical electrical equipment-Part 1:General requirements for safety, Registration technical review guidelines for infrared treatment equipment, etc. This paper analyzes and discusses the following aspects, including classification and applicable standards, performance indicators and overtemperature protection. Some suggestions and solutions are given to provide some guidance for medical equipment manufacturers in design, research and development and registration, in order to avoid the problem effectively and improve the passing rate of testing.


Assuntos
Desenho de Equipamento , Segurança de Equipamentos , Eletricidade , Raios Infravermelhos
9.
Small ; 15(31): e1901558, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31116907

RESUMO

Wearable electronic textiles based on natural biocompatible/biodegradable materials have attracted great attention due to applications in health care and smart clothes. Silkworm fibers are durable, good heat conductors, insulating, and biocompatible, and are therefore regarded as excellent mediating materials for flexible electronics. In this paper, a strategy on the design and fabrication of highly flexible multimode electronic textiles (E-textile) based on functionalized silkworm fiber coiled yarns and weaving technology is presented. To achieve enhanced temperature sensing performance, a mixture of carbon nanotubes and an ionic liquid ([EMIM]Tf2 N) is embedded, which displays top sensitivity of 1.23% °C-1 and stability compared with others. Furthermore, fibrous pressure sensing based on the capacitance change of each cross-point of two yarns gives rise to highly position dependent and sensitivity sensing of 0.136 kPa-1 . Based on weaving technologies, a unique combo textile sensor, which can sense temperature and pressure independently with a position precision of 1 mm2 , is obtained. The application to intelligent gloves endows the position dependent sensing of the weight, and temperature distribution sensing of the temperature.

10.
Int J Oncol ; 55(1): 69-80, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31115506

RESUMO

Neutrophil infiltration is frequently observed in lung cancer tissues. Extracellular RNAs (exRNAs) may facilitate tumor progression. The present study investigated the cross­talk of tumor exRNAs and neutrophil extracellular traps (NETs) in lung cancer. Lewis lung carcinoma (LLC) cells were cultured with the deprived sera. And the cell culture supernatants (CCS) were analyzed in vitro and in vivo. The results revealed that exRNAs from lung cancer CCS promoted the inflammatory cytokine interleukin­1ß and reduced the vascular cell adhesion molecule­1 expression in lung epithelial cells. Lung cancer CCS­treated epithelial cells induced the production of NETs. By contrast, NETs reduced the tight junction protein claudin­5 in epithelial cells. Furthermore, NETs caused the necrosis of epithelial cells, which resulted in the release of exRNAs. In mice, lung cancer cells instilled in the lung recruited neutrophils and initiated NETs. In patients with lung cancer, NETs were also observed. These results suggested that exRNAs in the cell culture supernatant may indirectly induce NETs and contribute to lung cancer oncogenesis.

11.
Talanta ; 201: 33-39, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31122430

RESUMO

High-pressure photoionization time-of-flight mass spectrometry (HPPI-TOFMS) is a versatile and highly sensitive analytical technique for online and real-time analysis of trace volatile organic compounds in complex mixtures. However, discrimination of isomers is usually a great challenge for the soft ionization method, and matrix effect is also inevitable under high pressure in the HPPI source. In this work, we describe a first attempt to develop a two-dimensional (2D) hyphenated instrument by coupling of a multi-capillary column (MCC) with a HPPI-TOFMS to overcome these problems. The capability of the MCC-HPPI-TOFMS for discrimination of isomeric compounds and elimination of the matrix effect was demonstrated by analyzing flavor mixtures. With the merits of fast separation, soft ionization and high detection sensitivity, satisfactory effects in the 2D analysis were achieved, despite the relatively low chromatographic resolution of MCC. As a result, three isomers, eucalyptol, l-menthone and linalool, in a flavor mixture were successfully categorized within 90 s, and the matrix effect caused by solvent ethanol was significantly eliminated as well. The limits of detection (LODs) down to sub-ppbv level were achieved for the investigated five flavor compounds without any enrichment process, and an excellent repeatability was obtained with the relative standard deviations (RSDs) of signal intensities ≤5%. The MCC-HPPI-TOFMS system was preliminarily applied for rapid and online analysis of flavor compounds in the exhaled gas of a volunteer after mouth rinsing with a gargle product. The rapid changes of the three flavor compounds, as well as the steady endogenous metabolite acetone, in the exhaled gas were successfully determined with a time-resolution of only 1.5 min.

12.
World Neurosurg ; 128: e334-e339, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31028986

RESUMO

BACKGROUND: The cerebellomesencephalic vein (CMV) was frequently sacrificed in surgery approached via the supracerebellar infratentorial (SCIT) route for resecting pineal region tumors, which resulted in potential risk of neurologic deficit. Preserving the CMV in the SCIT approach could enhance the safety and effectiveness of this natural corridor surgery. The aim of this article was to identify the probability and safety of preserving the CMV through the application of neuroendoscopy in the SCIT approach. METHODS: Clinical data of patients who underwent pineal region tumor resection through a purely endoscopic SCIT approach were retrospectively analyzed, focusing on surgical techniques and clinical outcomes. RESULTS: The study included 8 patients with pineal region tumors. The CMV was preserved intact in all patients. Total tumor removal was achieved in 7 of 8 patients. In 1 patient with 2 tumors in the pineal region and roof of the third ventricle, the tumor in the pineal region was resected completely, followed by subsequent chemotherapy combined with radiotherapy, after which the other tumor disappeared totally. All patients recovered normally with uneventful postoperative outcomes. CONCLUSIONS: The advantage of close observation and panoramic view provided by neuroendoscopy combined with meticulous manipulation improved the ability to preserve the CMV in resecting pineal region tumors via the SCIT approach. The neuroendoscopic technique enhances the safety and efficacy of the SCIT approach.

13.
J Cell Biochem ; 120(9): 15182-15189, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31020690

RESUMO

Stroke is one of the most destructive complications of sickle cell disease (SCD), and SCD is also the most common cause of childhood stroke. Sickle cell stroke is complex and has a genetic endothelial basis. Here, we further investigated this genetic basis using weighted gene coexpression network analysis. This systems biology approach revealed the correlation between coexpressed gene modules and sickle stroke risk. The pink module was significantly correlated with stroke risk and genes in this module were mainly related to GO:0044877 (protein-containing complex binding). In addition hub genes were identified through protein-protein interaction enrichment analysis, including CXCR7, VCAM1, CD44, BMP2, SMAD3, BCL2L1, ITPR2, ITPR3, etc. These hub genes were significantly enriched for three Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways including "gastric acid secretion," "pathways in cancer," and "TGF- ß signaling pathway." Altogether, our results based on this innovative method provided some novel understanding of the pathology of sickle cell stroke. Hub genes identified in this study could be potential targets for screening and prevention of stroke risk in SCD children.

14.
ACS Appl Mater Interfaces ; 11(17): 15195-15200, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30985101

RESUMO

This work demonstrates that engineering a three-dimensional photonic crystal (3DPC) structure in a highly flexible gel is a potential method to achieve flexible tactile artificial photonic skin (p-skin) for future visible-light communication (VLC). We investigated the photonic output modes of 3DPC-coated gel-based pressure sensors and explored their ability to sense low pressures (<10 kPa) through reflection. Such sensors with high sensitivity, fast response, and adjustable detection range can be fabricated in arrays of dots covering large, complex/uneven surfaces and are promising in the development of stimuli-responsive soft materials for future artificial intelligence, health monitoring, and photonic communication systems.


Assuntos
Géis/química , Pele Artificial , Potenciais de Ação , Inteligência Artificial , Comunicação , Luz , Fótons , Pressão , Propriedades de Superfície
15.
Endocrine ; 64(2): 414-419, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30989468

RESUMO

PURPOSE: Heart disease is a major cause of mortality and disability worldwide. Melatonin is a neuroendocrine hormone and has been found to be protective in heart disease. However, the molecular basis underlying this cardioprotective effect is not fully understood. Here we aim to investigate melatonin-sensitive genes in cardiovascular system using public gene expression databases. METHODS: An innovative genomic analysis method, the weighted gene co-expression network analysis (WGCNA) combined with differential gene expression analysis, was used in this study. The algorithm was implemented in R/Bioconductor. RESULTS: Using this method, we provide a comprehensive characterization of transcriptional profiles associated with melatonin treatment. We found that 357 differentially expressed genes (DEGs) were highly sensitive to melatonin in mouse myocardium. Enrichment analysis showed that these 357 genes were mostly related to GO:0051984 (positive regulation of chromosome segregation), GO:0016605 (PML body) and GO:0006281 (DNA repair). We further obtained 5 hub genes from the 357 DEGs, including Set, Dhx40, Scaf11, Cfh, and Nup43. CONCLUSIONS: We identified numerous melatonin-sensitive genes and further identified five hub genes. The five novel genes are possibly associated with the myocardial benefits of melatonin.

17.
J Chromatogr A ; 1591: 62-70, 2019 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-30712819

RESUMO

A well-defined molecularly imprinted polymer (Fe3O4@CS@MIP) was synthesized via reversible addition-fragmentation chain transfer polymerization for magnetic solid-phase extraction coupled with high-performance liquid chromatography-diode array detector to detect carbamazepine (CBZ) in biological samples. The composition of Fe3O4@CS@MIP was selected by a two-step screening method. 4-vinyl pyridine, divinylbenzene and dimethylformamide were chosen as the functional monomer, cross-linker and porogen, respectively. The imprinted layer was coated on the surface of the chain transfer agent-modified magnetic chitosan nanoparticles. The prepared Fe3O4@CS@MIP was characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller measurement and vibrating sample magnetometer. The results indicated that Fe3O4@CS@MIP had a large surface area (265.8 m2/g), high saturation magnetization (19.88 emu/g) and uniform structure. Besides, the binding property of the Fe3O4@CS@MIP was studied in detail. The Fe3O4@CS@MIP showed high imprinting factor (IF = 4.83) and desirable adsorption capacity (323.10 µmol/g) to CBZ. Under the optimum conditions, the developed method exhibited excellent linearity (R2>0.999) in the range of 0.01-0.5 mg/L and 1.0-30.0 mg/L, and the limits of detection were 1.0 µg/L and 9.6 µg/L for the urine and serum samples, respectively. Good recoveries (88.22%-101.18%) were obtained with relative standard deviations less than 4.83%. This work provided a practical approach for the selective extraction and detection of CBZ in real samples.


Assuntos
Carbamazepina/análise , Magnetismo , Impressão Molecular/métodos , Polimerização , Polímeros/química , Adsorção , Carbamazepina/sangue , Carbamazepina/urina , Cromatografia Líquida de Alta Pressão , Cinética , Limite de Detecção , Nanopartículas/química , Nanopartículas/ultraestrutura , Reprodutibilidade dos Testes , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier
18.
Artigo em Inglês | MEDLINE | ID: mdl-30795613

RESUMO

To assess different impacts of land, population and economy factors on the lexicographic minimax optimal allocation of blue and green water footprints, a comprehensive discriminant rule is constructed in this paper based on the Gini coefficient and Theil entropy index. The proposed rule is employed to estimate the influence of the aforesaid factors (land, population and economy) on the corresponding allocation schemes from a fairness perspective. To demonstrate its applicability, the proposed approach is applied to a water resources allocation study for 11 provinces in the Yangtze River Economic Belt (YREB). The results indicate that: (1) the economy-based lexicographic allocation of water footprints (LAWF) is more equalitarian for the provinces with high water footprint quotas. The land area-based LAWF is more equalitarian for the provinces with low water footprint quotas. The population-based LAWF is more equalitarian for the provinces with medium water footprint quotas. (2) The contribution of intra-regional variation in the population-based LAWF scheme is the largest of the three schemes. The inter-regional variation contributed the largest in the land area-based LAWF scheme. (3) Two synthetic schemes which integrate multiple factors among land area, economy and population are more equalitarian than the three single-factor schemes. Compared with the original situation which is an equalitarian but ineffective allocation, the two synthetic schemes have greater effect on the improvement of the supply-demand balance of water resources carrying capacity. Therefore, the defect of the population, economy and land area factors acting alone should be resolved by designing a weighting system, in order to optimize the allocation of water resources.


Assuntos
Rios/química , China , Cor , Conservação dos Recursos Naturais/métodos , Modelos Teóricos , Água
19.
Aging Cell ; 18(2): e12902, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30706990

RESUMO

Impairments of dendritic trees and spines have been found in many neurodegenerative diseases, including Alzheimer's disease (AD), in which the deficits of melatonin signal pathway were reported. Melatonin receptor 2 (MT2) is widely expressed in the hippocampus and mediates the biological functions of melatonin. It is known that melatonin application is protective to dendritic abnormalities in AD. However, whether MT2 is involved in the neuroprotection and the underlying mechanisms are not clear. Here, we first found that MT2 is dramatically reduced in the dendritic compartment upon the insult of oligomer Aß. MT2 activation prevented the Aß-induced disruption of dendritic complexity and spine. Importantly, activation of MT2 decreased cAMP, which in turn inactivated transcriptional factor CCAAT/enhancer-binding protein α(C/EBPα) to suppress miR-125b expression and elevate the expression of its target, GluN2A. In addition, miR-125b mimics fully blocked the protective effects of MT2 activation on dendritic trees and spines. Finally, injection of a lentivirus containing a miR-125b sponge into the hippocampus of APP/PS1 mice effectively rescued the dendritic abnormalities and learning/memory impairments. Our data demonstrated that the cAMP-C/EBPα/miR-125b/GluN2A signaling pathway is important to the neuroprotective effects of MT2 activation in Aß-induced dendritic injuries and learning/memory disorders, providing a novel therapeutic target for the treatment of AD synaptopathy.

20.
Angew Chem Int Ed Engl ; 58(16): 5376-5381, 2019 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-30761713

RESUMO

The synthesis of fully conjugated sp2 -carbon covalent organic frameworks (COF) is extremely challenging given the difficulty of the formation of very stable carbon-carbon double bonds (-C=C-). Here, we report the successful preparation of a 2D COF (TP-COF) based on triazine as central planar units bridged by sp2 -carbon linkers through the -C=C- condensation reaction. High-resolution-transmission electron microscopy (HRTEM) clearly confirmed the tessellated hexagonal pore structure with a pore center-to-center distance of 2 nm. Powder X-ray diffraction (PXRD) together with structural simulations revealed an AA stacking mode of the obtained layered structure. TP-COF turned out to be an excellent semiconductor material with a LUMO energy of -3.23 eV and a band gap of 2.36 eV. Excitingly, this novel sp2 -carbon conjugated TP-COF exhibited unprecedented coenzyme regeneration efficiency and can significantly boost the coenzyme-assisted synthesis of l-glutamate to a record-breaking 97 % yield within 12 minutes.

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