Publications by authors named "Fangyi Li"

33 Publications

Revealing the Dynamic Characteristics of Composite Material-Based Miura-Origami Tube.

Materials (Basel) 2021 Oct 25;14(21). Epub 2021 Oct 25.

School of Mechanical and Electrical Engineering, Guangzhou University, Guangzhou 510006, China.

Although Miura origami has excellent planar expansion characteristics and good mechanical properties, its congenital flaws, e.g., open sections leading to weak out-of-plane stiffness and constituting the homogenization of the material, and resulting in limited design freedom, should also be taken seriously. Herein, two identical Miura sheets, made of carbon fiber/epoxy resin composite, were bonded to form a tubular structure with closed sections, i.e., an origami tube. Subsequently, the dynamic performances, including the nature frequency and the dynamic displacement response, of the designed origami tubes were extensively investigated through numerical simulations. The outcomes revealed that the natural frequency and corresponding dynamic displacement response of the structure can be adjusted in a larger range by varying the geometric and material parameters, which is realized by combining origami techniques and the composite structures' characteristics. This work can provide new ideas for the design of light-weight and high-mechanical-performance structures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ma14216374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8585126PMC
October 2021

Phytochemical Constituents and Biological Activities of Plants from the Genus Cissampelos.

Chem Biodivers 2021 Oct 31;18(10):e2100358. Epub 2021 Aug 31.

College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China.

Cissampelos is a significant genus comprising of approximately 21 species of the medicinal plants (Menispermaceae). The plants of this genus are used in traditional medicine for the treatment of various ailments such as asthma, arthritis, dysentery, hyperglycemia, cardiopathy, hypertension and other related problems. These plants are rich in bioactive dibenzylisoquinoline and aborphine as well as small amounts of other ingredients. In recent years, the chemical constituents and pharmacological activities of Cissampelos genus have been paid more and more attention due to their diversity. Herein, we compile the chemical constituents and biological activities on this genus, and summarize the C-NMR data of the main bioactive ingredients. All information comes from scientific databases such as Google Scholar, PubMed, Sci-Finder, ScienceDirect, Web of Science and CNKI. It provides valuable data for the future research and development of Cissampelos genus.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cbdv.202100358DOI Listing
October 2021

Carbon deposition mechanism of molten salt cleaning and optimization of multicomponent molten salt formula for remanufacturing.

Sci Prog 2021 Jul-Sep;104(3):368504211031078

School of Mechanical Engineering, Shandong University, Jinan, Shandong, China.

In remanufacturing engineering, cleaning is the key factor for subsequent blank inspection and parts repair. Molten salt has the characteristics of low viscosity, good fluidity, and strong chemical stability. Salt bath cleaning can be comprehensively applied to remove various organic pollutants. Molten salt has the function of self-cleaning. The dirt in the cleaning pool can be decomposed and reused. Moreover, the waste molten salt is massive, and the waste residue is easy to treat. The formation and adsorption mechanism of carbon deposition was explored, and the formation mechanism of carbon deposition was verified by experiments. Then, the existing formula was improved by mixing experiment and compared with the current cleaning method; the cleaning effect was excellent. A new molten salt formula is proposed on the basis of the research on solar thermal storage medium. The composition percentage and the optimal process parameters of the new molten salt formula were determined on the basis of the experimental design of mixture. The cleaning effect of the new formula is good.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/00368504211031078DOI Listing
July 2021

Base-promoted, CBr-mediated tandem bromination/intramolecular Friedel-Crafts alkylation of N-aryl enamines: a facile access to 1H- and 3H-indoles.

Org Biomol Chem 2021 Jun 28;19(24):5377-5382. Epub 2021 May 28.

College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, P. R. China. and State Key Laboratory of Component-Based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, P. R. China.

Described here is a general and highly efficient method for the synthesis of 1H- and 3H-indoles. In the presence of CBr and a suitable base, the cyclization of N-aryl enamines proceeds with high efficiency. Unlike previous intramolecular cross dehydrogenative coupling (CDC) of the same substrates, this process does not require the use of either a transition metal or a stoichiometric amount of oxidant. This method also features operational simplicity, easy scalability and good substrate tolerability. Control experiments indicate the reactions may proceed in a tandem sequence of bromination and intramolecular Friedel-Crafts alkylation in a simple one-pot procedure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d1ob00731aDOI Listing
June 2021

Caspofungin pharmacokinetics and probability of target attainment in ICU patients in China.

J Glob Antimicrob Resist 2021 06 15;25:238-263. Epub 2021 Apr 15.

Department of Intensive Care Unit, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yan Jiang West Road, Guangzhou 510120, Guangdong, China. Electronic address:

Objectives: Effective antifungal therapy is important to reduce mortality in patients with invasive fungal infections (IFIs). Numerous factors affect pharmacokinetic/pharmacodynamic (PK/PD) parameters in critically-ill patients. To guide individualised administration in critically-ill patients, it is of great significance to determine the population pharmacokinetics of caspofungin.

Methods: A prospective study in 42 ICU patients with IFIs was conducted in China. A population pharmacokinetic model of caspofungin was established using a non-linear mixed-effects model, which was utilised to investigate the effects of demographic indices, liver function and kidney function on pharmacokinetics. Additionally, appropriate dosages of caspofungin under various scenarios were determined based on MICs and probability of target attainment (PTA) at specific dosages.

Results: In critically-ill Chinese patients, clearance (CL), volume of distribution (V) and area under the curve at steady-state (AUC) of caspofungin were 0.32 L/h, 6.77 L and 135.47 mg•h/L, respectively. Blood albumin and total bilirubin levels were factors affecting CL, while body weight was the only factor affecting V among Chinese people with relatively low weight compared with other populations. A maintenance dose of 50 mg caspofungin achieved a high PTA for treating IFIs caused by Candida albicans (MIC ≤ 0.06 mg/L) and Candida glabrata (MIC ≤ 0.125 mg/L). The maintenance dose of caspofungin should be adjusted to 70-200 mg for IFIs caused by C. albicans (MIC, 0.06-0.125 mg/L). For IFIs caused by Candida parapsilosis, an MIC > 0.03 mg/L is associated with a very low PTA, but higher doses of caspofungin or alternative antifungals need to be further studied.

Conclusion: The population pharmacokinetic model established here described well the PK/PD characteristics of caspofungin in critically-ill Chinese patients. These results could guide the formulation of individualised caspofungin dosing regimens for critically-ill patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jgar.2021.03.011DOI Listing
June 2021

Additive-Free Copper(I)-Mediated Synthesis of 5- or 6-Brominated 2-Aryl-1-Indole-3-Carboxylates from α,α-Dibromo β-Iminoesters.

J Org Chem 2021 01 4;86(2):1964-1971. Epub 2021 Jan 4.

College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, P. R. China.

Additive-free copper(I)-bromide-mediated radical cyclization reactions of α,α-dibromo β-iminoesters were investigated, enabling the synthesis of a series of 5- or 6-brominated 2-aryl-1-indole-3-carboxylates in moderate to good yields. The mechanistic study showed that (i) the bromine atom originated from the substrates and (ii) the bromination might be related to a 3-bromo-3 indole intermediate via an electrophilic bromine atom transfer. Furthermore, the practicality of this method was demonstrated by gram-scale synthesis and the potential for product derivatization toward other valuable multisubstituted indoles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.joc.0c02497DOI Listing
January 2021

Ten New Dammarane-Type Saponins with Hypolipidemia Activity from a Functional Herbal Tea-.

Molecules 2020 Aug 15;25(16). Epub 2020 Aug 15.

College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China.

(thumb.) Makino is a functional herbal tea commonly used in Asian countries and regions to reduce blood lipid levels. saponin is the main component, but there are still a large number of components with lipid-lowering activity that have not been found. In this study, 10 novel dammarane-type saponins, (-) and a known one () were isolated from . Ten new compounds were identified and named as yunnangypenosides A-J (-), and another known one () was also obtained. Their chemical structures were determined by MS, NMR spectroscopic analyses. Moreover, the cytotoxicities on human HepG-2 hepatocellular carcinoma cells of these isolates were evaluated, and the results showed that compounds - had no obvious cytotoxicity. Finally, all these compounds were evaluated for their lipid-lowering effect by means of the oil red O staining method. Ten compounds could significantly reduce lipid levels except of , especially exhibite the strongest hypolipidemia activity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/molecules25163737DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7464191PMC
August 2020

Can environmental innovation benefit from outward foreign direct investment to developed countries? Evidence from Chinese manufacturing enterprises.

Environ Sci Pollut Res Int 2020 Apr 7;27(12):13790-13808. Epub 2020 Feb 7.

School of Management, Hefei University of Technology, Hefei, 230009, Anhui Province, China.

Environmental innovation is an important way to low-carbon economic growth. Outward foreign direct investment (OFDI) can produce reverse technology transfer to promote innovation. This study aims to examine whether OFDI to developed countries can transfer reverse green technology and promote the environmental innovation of manufacturing enterprises in emerging economies (EEs). Based on the technology gap theory, resource bricolage theory, resource-based view, and Potter hypothesis, this study constructs a conceptual model including the direct effect of OFDI on environmental innovation and the moderating effects of the knowledge level of the host country, multinational strategy, absorptive capacity, and environmental regulation. To verify the model, we also use a panel dataset of 424 Chinese manufacturing enterprises during 2010-2017, and the results indicate that OFDI to developed countries can produce reverse green technology transfer and promote parent companies' environmental innovation. The knowledge level of the host country and multinational strategy can further improve the impacts on environmental product innovation. However, absorptive capacity and environmental regulation in EEs do not play a significant moderating role. Consequently, this study expands the application scope of existing theories and enriches the theoretical basis of the relationship between OFDI and environmental innovation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11356-020-07819-zDOI Listing
April 2020

ANFIS Construction With Sparse Data via Group Rule Interpolation.

IEEE Trans Cybern 2021 May 15;51(5):2773-2786. Epub 2021 Apr 15.

A major assumption for constructing an effective adaptive-network-based fuzzy inference system (ANFIS) is that sufficient training data are available. However, in many real-world applications, this assumption may not hold, thereby requiring alternative approaches. In light of this observation, this article focuses on automated construction of ANFISs in an effort to enhance the potential of the Takagi-Sugeno fuzzy regression models for situations where only limited training data are available. In particular, the proposed approach works by interpolating a group of fuzzy rules in a certain given domain with the assistance of existing ANFISs in its neighboring domains. The construction process involves a number of computational mechanisms, including a rule dictionary which is created by extracting the rules from the existing ANFISs; a group of rules which are interpolated by exploiting the local linear embedding algorithm to build an intermediate ANFIS; and a fine-tuning method which refines the resulting intermediate ANFIS. The experimental evaluation on both synthetic and real-world datasets is reported, demonstrating that when facing the data shortage situations, the proposed approach helps significantly improve the performance of the original ANFIS modeling mechanism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1109/TCYB.2019.2952267DOI Listing
May 2021

Chemical Constituents with Inhibitory Activity of NO Production from a Wild Edible Mushroom, Lindbl, May Be Its Nutritional Ingredients.

Molecules 2019 Apr 3;24(7). Epub 2019 Apr 3.

College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China.

Lindbl is a wild edible mushroom that is usually used for original material of food and soup and has rich nutritional value. What are the nutritional ingredients? In order to answer this question, we investigated the chemical constituents of this wild functional food. Six new compounds (-), together with nine known ones (-), were isolated from . The six new compounds were named as vinosane (), rulepidadione C (), (24)-3,4-seco-cucurbita-4,24-diene-26,29-dioic acid-3-methyl ester (), (24)-3,4-seco-cucurbita-4,24-diene-26-oic acid-3-ethyl ester (), (24)-3β-hydroxycucurbita-5,24-diene-26,29-dioic acid (), and (2,3,4,2')-2-(2'-hydroxydocosanoylamino)eicosane-1,3,4-triol (). Their structures were determined based on spectroscopic methods including HR-ESI-MS, 1D, and 2D NMR. Moreover, a cell counting kit-8 (CCK-8 kit) was used to screen for the cytotoxicity of compounds - and - on mouse macrophage RAW 264.7 cells. The results showed that compounds - and - had no obvious cytotoxicity. In addition, the inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated mouse macrophage RAW 264.7 cells were evaluated. Compounds , , , , , and showed moderate inhibitory activity on NO production.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/molecules24071305DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6479787PMC
April 2019

Identification of Vibration Events in Rotating Blades Using a Fiber Optical Tip Timing Sensor.

Sensors (Basel) 2019 Mar 27;19(7). Epub 2019 Mar 27.

State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China.

The blade tip timing (BTT) technique has been widely used in rotation machinery for non-contact blade vibration measurements. As BTT data is under-sampled, it requires complicated algorithms to reconstruct vibration parameters. Before reconstructing the vibration parameters, the right data segment should first be extracted from the massive volumes of BTT data that include noise from blade vibration events. This step requires manual intervention, is highly dependent on the skill of the operator, and has also made it difficult to automate BTT technique applications. This article proposes an included angle distribution (IAD) correlation method between adjacent revolutions to identify blade vibration events automatically in real time. All included angles of the rotor between any two adjacent blades were accurately detected by only one fiber optical tip timing sensor. Three formulas for calculating IAD correlation were then proposed to identify three types of blade vibration events: the blades' overall vibrations, vibration of the adjacent two blades, and vibration of a specific blade. Further, the IAD correlation method was optimized in the calculating process to reduce computation load when identifying every blade's vibration events. The presented IAD correlation method could be used for embedded, real-time, and automatic processing applications. Experimental results showed that the proposed method could identify all vibration events in rotating blades, even small events which may be wrongly identified by skillful operators.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/s19071482DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6479853PMC
March 2019

Fuzzy Knowledge-Based Prediction Through Weighted Rule Interpolation.

IEEE Trans Cybern 2020 Oct 28;50(10):4508-4517. Epub 2019 Jan 28.

Fuzzy rule interpolation (FRI) facilitates approximate reasoning in fuzzy rule-based systems only with sparse knowledge available, remedying the limitation of conventional compositional rule of inference working with a dense rule base. Most of the existing FRI work assumes equal significance of the conditional attributes in the rules while performing interpolation. Recently, interesting techniques have been reported for achieving weighted interpolative reasoning. However, they are either particularly tailored to perform classification problems only or employ attribute weights that are obtained using additional information (rather than just the given rules), without integrating them with the associated FRI procedure. This paper presents a weighted rule interpolation scheme for performing prediction tasks by the use of fuzzy sparse knowledge only. The weights of rule conditional attributes are learned from a given rule base to discriminate the relative significance of each individual attribute and are integrated throughout the internal mechanism of the FRI process. This scheme is demonstrated using the popular scale and move transformation-based FRI for resolving prediction problems, systematically evaluated on 12 benchmark prediction tasks. The performance is compared with the relevant state-of-the-art FRI techniques, showing the efficacy of the proposed approach.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1109/TCYB.2018.2887340DOI Listing
October 2020

Investigation of the Assembly Behavior of an Amphiphilic Lipopeptide at the Liquid Crystal-Aqueous Interface.

Langmuir 2019 02 8;35(7):2490-2497. Epub 2019 Feb 8.

In this article, we designed an amphiphilic lipopeptide molecule, 5(6)-carboxyfluorescein-KKKKKKSKTK-Cys(CH)-OMe (FAM-lipopeptide-C12), and studied its assembly behavior at the 4-cyano-4'-pentylbiphenyl (5CB)-aqueous interface. The ordering transitions of liquid crystals (LCs) revealed that FAM-lipopeptide-C12 can assemble at the LC-aqueous interface (both planar and curved interfaces). The assembly can be destroyed by adding trypsin, which catalyzes the hydrolysis of lipopeptides. Fluorescence measurements further confirmed the assembly and deassembly behavior of FAM-lipopeptide-C12 at the LC-aqueous interface. Overall, our work provides a general method for the construction of a biointerface by directly assembling amphiphilic lipopeptides at the LC-aqueous interface, which can potentially be used in selectively detecting the activity of specific enzymes and other biomolecular interactions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.langmuir.8b03294DOI Listing
February 2019

A Risk Prediction Model for Invasive Fungal Disease in Critically Ill Patients in the Intensive Care Unit.

Asian Nurs Res (Korean Soc Nurs Sci) 2018 Dec 22;12(4):299-303. Epub 2018 Nov 22.

Department of Intensive Care Unit, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China. Electronic address:

Purpose: Developing a risk prediction model for invasive fungal disease based on an analysis of the disease-related risk factors in critically ill patients in the intensive care unit (ICU) to diagnose the invasive fungal disease in the early stages and determine the time of initiating early antifungal treatment.

Methods: Data were collected retrospectively from 141 critically ill adult patients with at least 4 days of general ICU stay at Sun Yat-sen Memorial Hospital, Sun Yat-sen University during the period from February 2015 to February 2016. Logistic regression was used to develop the risk prediction model. Discriminative power was evaluated by the area under the receiver operating characteristics (ROC) curve (AUC).

Results: Sequential organ failure assessment (SOFA) score, antibiotic treatment period, and positive culture of Candida albicans other than normally sterile sites are the three predictors of invasive fungal disease in critically ill patients in the ICU. The model performs well with an ROC-AUC of .73.

Conclusion: The risk prediction model performs well to discriminate between critically ill patients with or without invasive fungal disease. Physicians could use this prediction model for early diagnosis of invasive fungal disease and determination of the time to start early antifungal treatment of critically ill patients in the ICU.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.anr.2018.11.004DOI Listing
December 2018

Metal- and base-free synthesis of functionalized α,α-difluoroimines via electrophilic fluorination of N-substituted enamines.

Org Biomol Chem 2018 10;16(38):6895-6899

College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China.

A metal- and base-free synthesis of functionalized α,α-difluoroimines is presented. The reaction features mild conditions, high E/Z control and broad functional group tolerance. The utility of the products was demonstrated through valuable synthetic transformations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8ob01941jDOI Listing
October 2018

Edge-Rich Quasi-Mesoporous Nitrogen-Doped Carbon Framework Derived from Palm Tree Bark Hair for Electrochemical Applications.

ACS Appl Mater Interfaces 2018 Aug 6;10(32):27047-27055. Epub 2018 Aug 6.

School of Chemistry and Chemical Engineering , Hunan Institute of Science and Technology , Yueyang 414006 , China.

Biomass with abundant resources and low price is regarded as potential sources of functionalized carbon-based energy storage and conversion electrode materials. Rational construction and development of biomass-derived carbon equipped with proper morphology, structure, and composition prove the key to highly efficient utilization of advanced energy storage systems. Herein, we use palm tree bark hair as a biomass source and prepare edge/defect-rich quasi-mesoporous carbon (QMC) by a direct pyrolysis followed by NaOH etching strategy. Then, the edge-rich quasi-mesoporous nitrogen-doped carbon (QMNC) is successfully fabricated through the hydrothermal method by making use of edge/defect-rich QMC and urea as carbon precursor and nitrogen source, respectively. The microstructure and composition of the resultant carbon materials are all detected by a series of techniques. In the meantime, the influence of the etching process on the preparation and electrochemical performance of edge-rich QMNC is systematically explored. The relevant results manifest that the as-prepared edge/defect-rich QMC not only possesses edge-rich plane, much increased specific surface area (SSA), and special quasi-mesopores but also reverses good conductivity and gains sufficient defects for subsequent N doping. After introducing N atoms, the obtained edge-rich QMNC exhibits outstanding capacitive property and oxygen reduction reaction performance, which are mainly attributed to the co-effect of edge-rich plane, large SSA, suitable pore structures, and effective N doping (including high doping amount and optimized N configurations). Clearly, our work not only offers an excellent biomass-derived carbon-based electrode material but also opens a fresh avenue for the development of advanced biomass-derived carbon-based electrode materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.8b08418DOI Listing
August 2018

A new biodegradable sisal fiber-starch packing composite with nest structure.

Carbohydr Polym 2018 Jun 31;189:56-64. Epub 2018 Jan 31.

School of Mechanical Engineering, Key Laboratory of High Efficiency and Clean Mechanical Manufacture (Ministry of Education) Shandong University, Jinan 250061, China; National Demonstration Center for Experimental Mechanical Engineering Education (Shandong University), Jinan 250061, China.

A new completely biodegradable sisal fiber-starch packing composite was proposed. The effects of fiber content and alkaline treatment on the cushioning property of the composites were studied from energy absorption efficiency, cellular microstructure and compatibility between fiber and starch. With increasing fiber content, the nest structure of composites becomes dense first and then loosens, resulting in initial enhancement and subsequent weakening of the cushioning property of the composites. The composite with 4:13 mass ratio of fiber and thermoplastic starch (TPS) exhibit the optimal cushioning property. Alkaline treatment increases the compatibility between sisal fiber and TPS, promotes the formation of dense nest structure, thereby enhances the cushioning property of the composites. After biodegradability tests for 28 days, the weight loss of the composites was 62.36%. It's found that the composites are a promising replacement for expandable polystyrene (EPS) as packing material, especially under large compression load (0.7-6 MPa).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.carbpol.2018.01.063DOI Listing
June 2018

Enantioselective [3+3] atroposelective annulation catalyzed by N-heterocyclic carbenes.

Nat Commun 2018 02 9;9(1):611. Epub 2018 Feb 9.

School of Pharmaceutical Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology (Ministry of Education), Tsinghua University Beijing, 100084, Beijing, China.

Axially chiral molecules are among the most valuable substrates in organic synthesis. They are typically used as chiral ligands or catalysts in asymmetric reactions. Recent progress for the construction of these chiral molecules is mainly focused on the transition-metal-catalyzed transformations. Here, we report the enantioselective NHC-catalyzed (NHC: N-heterocyclic carbenes) atroposelective annulation of cyclic 1,3-diones with ynals. In the presence of NHC precatalyst, base, Lewis acid and oxidant, a catalytic C-C bond formation occurs, providing axially chiral α-pyrone-aryls in moderate to good yields and with high enantioselectivities. Control experiments indicated that alkynyl acyl azoliums, acting as active intermediates, are employed to atroposelectively assemble chiral biaryls and such a methodology may be creatively applied to other useful NHC-catalyzed asymmetric transformations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-018-02952-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5807440PMC
February 2018

Facile Synthesis of ZnS/N,S Co-doped Carbon Composite from Zinc Metal Complex for High-Performance Sodium-Ion Batteries.

ACS Appl Mater Interfaces 2018 Jan 28;10(1):704-712. Epub 2017 Dec 28.

Department of Chemistry, University of Missouri-Kansas City , Kansas City, Missouri 64110, United States.

ZnS coated on N,S co-doped carbon (ZnS/NSC) composite has been prepared utilizing zinc pyrithione (CHNOSZn) as raw material via calcination. Through activation using NaCO salt, ZnS nanoparticles encapsulated in NSC (denoted as A-ZnS/NSC) with mixed-crystal structure has also been obtained, which reveals much larger specific surface area and more bridges between ZnS and NSC. Based on the existence of bridges (C-S-Zn and S-O-Zn bonds) and the modification of carbon from N,S co-doping, the A-ZnS/NSC composite as an anode for sodium-ion batteries (SIBs) displays significantly enhanced electrochemical performances with a high reversible specific capacity of 516.6 mA h g (at 100 mA g), outstanding cycling stability (96.9% capacity retention after 100 cycles at 100 mA g), and high rate behavior (364.9 mA h g even at 800 mA g).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.7b15659DOI Listing
January 2018

Landscape of the regulatory elements for lysine 2-hydroxyisobutyrylation pathway.

Cell Res 2018 01 1;28(1):111-125. Epub 2017 Dec 1.

Ben May Department for Cancer Research, The University of Chicago, Chicago, IL 60637, USA.

Short-chain fatty acids and their corresponding acyl-CoAs sit at the crossroads of metabolic pathways and play important roles in diverse cellular processes. They are also precursors for protein post-translational lysine acylation modifications. A noteworthy example is the newly identified lysine 2-hydroxyisobutyrylation (K) that is derived from 2-hydroxyisobutyrate and 2-hydroxyisobutyryl-CoA. Histone K has been shown to be associated with active gene expression in spermatogenic cells. However, the key elements that regulate this post-translational lysine acylation pathway remain unknown. This has hindered characterization of the mechanisms by which this modification exerts its biological functions. Here we show that Esa1p in budding yeast and its homologue Tip60 in human could add K to substrate proteins both in vitro and in vivo. In addition, we have identified HDAC2 and HDAC3 as the major enzymes to remove K. Moreover, we report the first global profiling of K proteome in mammalian cells, identifying 6 548 K sites on 1 725 substrate proteins. Our study has thus discovered both the "writers" and "erasers" for histone K marks, and major K protein substrates. These results not only illustrate the landscape of this new lysine acylation pathway, but also open new avenues for studying diverse functions of cellular metabolites associated with this pathway.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/cr.2017.149DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5752845PMC
January 2018

Effects of Sleep Deprivation on Phase Synchronization as Assessed by Wavelet Phase Coherence Analysis of Prefrontal Tissue Oxyhemoglobin Signals.

PLoS One 2017 3;12(1):e0169279. Epub 2017 Jan 3.

Key Laboratory of Rehabilitation Aids Technology and System of the Ministry of Civil Affairs, National Research Center for Rehabilitation Technical Aids, Beijing, P.R. China.

Purpose: To reveal the physiological mechanism of the decline in cognitive function after sleep deprivation, a within-subject study was performed to assess sleep deprivation effects on phase synchronization, as revealed by wavelet phase coherence (WPCO) analysis of prefrontal tissue oxyhemoglobin signals.

Materials And Methods: Twenty subjects (10 male and 10 female, 25.5 ± 3.5 years old) were recruited to participate in two tests: one without sleep deprivation (group A) and the other with 24 h of sleep deprivation (group B). Before the test, each subject underwent a subjective evaluation using visual analog scales. A cognitive task was performed by judging three random numbers. Continuous recordings of the near-infrared spectroscopy (NIRS) signals were obtained from both the left and right prefrontal lobes during rest, task, and post-task periods. The WPCO of cerebral Delta [HbO2] signals were analyzed for these three periods for both groups A and B.

Results: Six frequency intervals were defined: I: 0.6-2 Hz (cardiac activity), II: 0.145-0.6 Hz (respiratory activity), III: 0.052-0.145 Hz (myogenic activity), IV: 0.021-0.052 Hz (neurogenic activity), V: 0.0095-0.021 Hz (nitric oxide related endothelial activity) and VI: 0.005-0.0095 Hz (non-nitric oxide related endothelial activity). WPCO in intervals III (F = 5.955, p = 0.02) and V (F = 4.7, p = 0.037) was significantly lower in group B than in group A at rest. During the task period, WPCO in intervals III (F = 5.175, p = 0.029) and IV (F = 4.585, p = 0.039) was significantly lower in group B compared with group A. In the post-task recovery period, the WPCO in interval III (F = 6.125, p = 0.02) was significantly lower in group B compared with group A. Reaction time was significantly prolonged, and the accuracy rate and F1 score both declined after sleep deprivation.

Conclusions: The decline in WPCO after sleep deprivation indicates reduced phase synchronization between left and right prefrontal oxyhemoglobin oscillations, which may contribute to the diminished cognitive function.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0169279PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5207699PMC
August 2017

Wavelet coherence analysis of cerebral oxygenation signals measured by near-infrared spectroscopy in sailors: an exploratory, experimental study.

BMJ Open 2016 11 3;6(11):e013357. Epub 2016 Nov 3.

Key Laboratory of High Efficiency and Clean Mechanical Manufacture, School of Mechanical Engineering, Shandong University, Jinan, Shandong, P. R. China.

Objective: The objective of this study was to assess the effects of long-term offshore work on cerebral oxygenation oscillations in sailors based on the wavelet phase coherence (WPCO) of near-infrared spectroscopy (NIRS) signals.

Methods: The fatigue severity scale (FSS) was first applied to assess the fatigue level of sailors and age-matched controls. Continuous recordings of NIRS signals were then obtained from the prefrontal lobes in 30 healthy sailors and 30 age-matched controls during the resting state. WPCO between the left and right prefrontal oscillations was analysed and Pearson correlation analysis was used to study the relationship between the FSS and the wavelet amplitude (WA), and between the FSS and the WPCO level.

Results: The periodic oscillations of Delta (HbO) signals were identified at six frequency intervals: I (0.6-2 Hz); II (0.145-0.6 Hz); III (0.052-0.145 Hz); IV (0.021-0.052 Hz); V (0.0095-0.021 Hz); and VI (0.005-0.0095 Hz). The WA in intervals I (F=8.823, p=0.004) and III (F=4.729, p=0.034) was significantly lower in sailors than that in the controls. The WPCO values of sailor group were significantly lower in intervals III (F=4.686, p=0.039), IV (F=4.864, p=0.036) and V (F=5.195, p=0.03) than those of the control group. In the sailor group, the WA in interval I (r=-0.799, p<0.01) and in interval III (r=-0.721, p<0.01) exhibited a negative correlation with the FSS. Also, the WPCO exhibited a negative correlation with the FSS in intervals III (r=-0.839, p<0.01), IV (r=-0.765, p<0.01) and V (r=-0.775, p<0.01) in the sailor group.

Conclusions: The negative correlation between WA and FSS indicates that the lower oscillatory activities might contribute to the development of fatigue. The low WPCO in intervals III, IV and V represents a reduced phase synchronisation of myogenic, neurogenic and endothelial metabolic activities respectively and this may suggest a decline of cognitive function.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/bmjopen-2016-013357DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5128848PMC
November 2016

Image fusion via nonlocal sparse K-SVD dictionary learning.

Appl Opt 2016 Mar;55(7):1814-23

Image fusion aims to merge two or more images captured via various sensors of the same scene to construct a more informative image by integrating their details. Generally, such integration is achieved through the manipulation of the representations of the images concerned. Sparse representation plays an important role in the effective description of images, offering a great potential in a variety of image processing tasks, including image fusion. Supported by sparse representation, in this paper, an approach for image fusion by the use of a novel dictionary learning scheme is proposed. The nonlocal self-similarity property of the images is exploited, not only at the stage of learning the underlying description dictionary but during the process of image fusion. In particular, the property of nonlocal self-similarity is combined with the traditional sparse dictionary. This results in an improved learned dictionary, hereafter referred to as the nonlocal sparse K-SVD dictionary (where K-SVD stands for the K times singular value decomposition that is commonly used in the literature), and abbreviated to NL_SK_SVD. The performance of the NL_SK_SVD dictionary is applied for image fusion using simultaneous orthogonal matching pursuit. The proposed approach is evaluated with different types of images, and compared with a number of alternative image fusion techniques. The resultant superior fused images using the present approach demonstrates the efficacy of the NL_SK_SVD dictionary in sparse image representation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/AO.55.001814DOI Listing
March 2016

N-Heterocyclic Carbene Catalyzed Dynamic Kinetic Resolution of Pyranones.

Angew Chem Int Ed Engl 2016 Jan 6;55(5):1820-4. Epub 2015 Nov 6.

Department of Pharmacology and Pharmaceutical Sciences, School of Medicine, Tsinghua University, Beijing, 100084, China.

The dynamic kinetic resolution of 6-hydroxypyranones with enals or alkynals through an asymmetric redox esterification is catalyzed by a chiral N-heterocyclic carbene. The resulting esters are obtained in good to high yields and with high levels of enantio- and diastereocontrol. The reaction products are further derivatized to obtain functionalized sugar derivatives and natural products.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.201508205DOI Listing
January 2016

Chemoselective N-Heterocyclic Carbene-Catalyzed Cascade of Enals with Nitroalkenes.

Org Lett 2015 Jul 6;17(14):3588-91. Epub 2015 Jul 6.

Department of Pharmacology and Pharmaceutical Science, School of Medicine, Tsinghua University, Beijing 117543, China.

An unprecedented N-heterocyclic carbene catalyzed chemoselective and enantioselective cascade reaction of enals with nitroalkenes has been developed. A wide range of enantioenriched dihydrocoumarins has been prepared, and the reaction goes through an enolate intermediate generated under a catalytic process.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.orglett.5b01692DOI Listing
July 2015

Intermolecular dynamic kinetic resolution cooperatively catalyzed by an N-heterocyclic carbene and a Lewis acid.

Angew Chem Int Ed Engl 2015 Jan 28;54(5):1629-33. Epub 2014 Nov 28.

Department of Pharmacology and Pharmaceutical Sciences, School of Medicine, Tsinghua University, Beijing, 100084 (China).

The ubiquitous structure of δ-lactones makes the development of new methods for their enantioselective and stereoselective synthesis an important ongoing challenge. The intermolecular dynamic kinetic resolution (DKR) of β-halo-α-ketoesters cooperatively catalyzed by an N-heterocyclic carbene and a Lewis acid generates two contiguous stereocenters with remarkable diastereoselectivity through an oxidation/lactonization sequence.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.201410030DOI Listing
January 2015

Oxidative enantioselective α-fluorination of aliphatic aldehydes enabled by N-heterocyclic carbene catalysis.

Angew Chem Int Ed Engl 2015 Jan 27;54(2):656-9. Epub 2014 Oct 27.

Department of Pharmacology and Pharmaceutical Sciences, School of Medicine, Tsinghua University, Beijing, 100084 (China).

Described is the first study on oxidative enantioselective α-fluorination of simple aliphatic aldehydes enabled by N-heterocyclic carbene catalysis. N-fluorobis(phenyl)sulfonimide serves as a an oxidant and as an "F" source. The C-F bond formation occurs directly at the α position of simple aliphatic aldehydes, thus overcoming nontrivial challenges, such as competitive difluorination and nonfluorination, and proceeds with high to excellent enantioselectivities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.201409473DOI Listing
January 2015

Homeobox B9 is overexpressed in hepatocellular carcinomas and promotes tumor cell proliferation both in vitro and in vivo.

Biochem Biophys Res Commun 2014 Feb 22;444(2):241-7. Epub 2014 Jan 22.

Department of Emergency, Zhongshan Hospital of Dalian University, No. 6 Jiefang Street, Zhongshan District, Dalian 116001, China. Electronic address:

HomeoboxB9 (HOXB9), a nontransforming transcription factor that is overexpressed in multiple tumor types, alters tumor cell fate and promotes tumor progression. However, the role of HOXB9 in hepatocellular carcinoma (HCC) development has not been well studied. In this paper, we found that HOXB9 is overexpressed in human HCC samples. We investigated HOXB9 expression and its prognostic value for HCC. HCC surgical tissue samples were taken from 89 HCC patients. HOXB9 overexpression was observed in 65.2% of the cases, and the survival analysis showed that the HOXB9 overexpression group had significantly shorter overall survival time than the HOXB9 downexpression group. The ectopic expression of HOXB9 stimulated the proliferation of HCC cells; whereas the knockdown of HOXB9 produced an opposite effect. HOXB9 also modulated the tumorigenicity of HCC cells in vivo. Moreover, we found that the activation of TGF-β1 contributes to HOXB9-induced proliferation activities. The results provide the first evidence that HOXB9 is a critical regulator of tumor growth factor in HCC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbrc.2014.01.059DOI Listing
February 2014

Microwave degradation of methyl orange dye in aqueous solution in the presence of nano-TiO2-supported activated carbon (supported-TiO2/AC/MW).

J Hazard Mater 2012 Mar 20;209-210:271-7. Epub 2012 Jan 20.

College of Environment, Liaoning University, Shenyang 110036, People's Republic of China.

In this study, nano-TiO(2)-supported activated carbon (TiO(2)/AC) was developed for the microwave (MW) degradation of an azo dye, methyl orange (MO), selected as a model contaminant in aqueous solution. The effects of selected process parameters such as supported TiO(2) content, MW irradiation time, initial MO concentration, catalyst dose, and solution pH on the degradation were assessed in detail. The results showed that the supported TiO(2) on AC could be excited resulting in the production of hydroxyl radical (OH) in aqueous solution under MW irradiation, which significantly enhanced the performance of AC/MW process for the degradation of MO. Also, the supported-TiO(2)/AC displayed higher catalytic activity than AC alone under MW irradiation. By comparison, the supported-TiO(2)/AC/MW process exhibited several advantages, including high degradation rate, short irradiation time, no residual intermediates and no secondary pollution. Hence, it shows to be a promising technology for the destruction of organic contaminants in dye treatment applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhazmat.2012.01.021DOI Listing
March 2012

[Breeding and spreading of new vairety "Yu-Qing No. 1" of Artemisia annua].

Zhongguo Zhong Yao Za Zhi 2010 Oct;35(19):2516-22

Chongqing Academy of Chinese Materia, Chongqing 400065, China.

Objective: To breed and spread a new cultivar of Artemisia annua.

Method: The excellent germplasm resources of A. annua in the main production area of Artemisia were collected, and the improved germplasm were screened, the content of artemisinin was determined, and yield per plant was measured. The systematically maternal line and seed production techniques of mass selection were applied combined with the variety test, variety regional test trials and production trials for breeding and spreading the new cultivars of artemisia.

Result: The popularization and experiment illustrated the production of the new species reached 3 000 kg x hm(-2), compared with wild A. annua it increased 10% -14%. The content of artemisinin reached more than 1%, increased more than 0.2%.

Conclusion: It is proved that the systematically maternal line and seed production techniques of mass selection can significantly improve the quality of A. annua and it is an acceptable way to cultivate new variety. By production verification, it is practicable and high technical and economic benefits to popularize the new cultivar "Yu-Qing No. 1" of A. annua.
View Article and Find Full Text PDF

Download full-text PDF

Source
October 2010
-->