668,821 results match your criteria structures human

The Complex Dynamics of Earthquake Fault Systems: New Approaches to Forecasting and Nowcasting of Earthquakes.

Rep Prog Phys 2021 Apr 15. Epub 2021 Apr 15.

Physics and Astronomy, University of California Davis, 1 Shields Ave., Davis, California, 95616-5270, UNITED STATES.

Charles Richter's observation that "only fools and charlatans predict earthquakes," reflects the fact that despite more than 100 years of effort, seismologists remain unable to do so with reliable and accurate results. Meaningful prediction involves specifying the location, time, and size of an earthquake before it occurs to greater precision than expected purely by chance from the known statistics of earthquakes in an area. In this context, "forecasting" implies a prediction with a specification of a probability of the time, location, and magnitude. Read More

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Mesoporous zirconia surfaces with anti-biofilm properties for dental implants.

Biomed Mater 2021 Apr 15. Epub 2021 Apr 15.

Department of Chemistry, Materials and Chemical Engineering 'G. Natta', Politecnico di Milano, Via Mancinelli 7, Milano, 20133, ITALY.

Cytocompatible bioactive surface treatments conferring antibacterial properties to osseointegrated dental implants are highly requested to prevent bacteria-related peri-implantitis. Here we focus on a newly designed family of mesoporous coatings based on zirconia (ZrO2) microstructure doped with gallium (Ga), exploiting its antibacterial and pro-osseo-integrative properties. The ZrO2 films were obtained via sol-gel synthesis route using Pluronic F127 as templating agent, while Ga doping was gained by introducing gallium nitrate hydrate. Read More

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Processing variables of direct-write, near-field electrospinning impact size and morphology of gelatin fibers.

Biomed Mater 2021 Apr 15. Epub 2021 Apr 15.

Biomedical Engineering, North Carolina State University, 4130 Engineering Building III, Campus Box 7115, Raleigh, North Carolina, 27695, UNITED STATES.

Several biofabrication methods are being investigated to produce scaffolds that can replicate the structure of the extracellular matrix. Direct-write, near-field electrospinning of polymer solutions and melts is one such method which combines fine fiber formation with computer-guided control. Research with such systems has focused primarily on synthetic polymers. Read More

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Fracture fingerprint of polycrystalline CN nanosheets: Theoretical basis.

J Mol Graph Model 2021 Mar 21;106:107899. Epub 2021 Mar 21.

Center of Excellence in Electrochemistry, School of Chemistry, College of Science, University of Tehran, Tehran, Iran. Electronic address:

Polycrystalline carbon nanosheets are composed of several randomly rotated monocrystalline regions facing each other in grain boundaries-the cause of stress concentration-that affects the mechanics of 2D carbon nanostructures. They have been widely used in different fields, particularly in electronic devices. Herein, heterogeneous graphitic carbon nitride (CN) was considered as typical of polycrystalline carbon nanosheets for modelling its fracture behavior. Read More

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Qualitative distribution of endogenous sphingolipids in plasma of human and rodent species by UPLC-Q-Exactive-MS.

J Chromatogr B Analyt Technol Biomed Life Sci 2021 Apr 2;1173:122684. Epub 2021 Apr 2.

Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan 430030, China. Electronic address:

Sphingolipids (SLs) are endogenously bioactive molecules with diverse structures, and its metabolic disorders are involved in the progression of many diseases. In this study, an ultra-performance liquid chromatography quadrupole exactive mass spectrometry (UPLC-Q-Exactive-MS) method was established to comprehensively profile SLs in plasma. First, the fragment patterns of SL standards of each subclass were investigated. Read More

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Residential green space structures are associated with a lower risk of bipolar disorder: A nationwide population-based study in Taiwan.

Environ Pollut 2020 Oct 15;283:115864. Epub 2020 Oct 15.

Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan. Electronic address:

Although many researchers have identified the potential psychological benefits offered by greenness, the association between green space structures and mental disorders is not well understood. The purpose of this study was to identify associations between green space structures and the incidence of bipolar disorder. To this end, we investigated 1,907,776 individuals collected from Taiwan's National Health Insurance Research Database. Read More

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October 2020

Actin cytoskeletal structure and the statistical variations of the mechanical properties of non-tumorigenic breast and triple-negative breast cancer cells.

J Mech Behav Biomed Mater 2021 Apr 9;119:104505. Epub 2021 Apr 9.

Department of Materials Science and Engineering, Biomaterials Lab, African University of Science and Technology, Km 10 Airport Road, Galadimawa, Abuja, Federal Capital Territory, Nigeria; Department of Mechanical Engineering, Higgins Lab, Worcester Polytechnic Institute (WPI), 100 Institute Road, Worcester, MA 10609, USA; Department of Biomedical Engineering, Gateway Park Life Sciences Center, Worcester Polytechnic Institute (WPI), 60 Prescott Street, Worcester, MA 01605, USA. Electronic address:

This paper presents the results of a study of the actin cytoskeletal structures and the statistical variations in the actin fluorescence intensities and viscoelastic properties of non-tumorigenic breast cells and triple-negative breast cancer cells at different stages of tumor progression. The variation in the actin content of the cell cytoskeletal structures is shown to be consistent with the viscoelastic properties of the cell as it progresses from non-tumorigenic to more metastatic states. The corresponding viscoelastic properties of the nuclei and the cytoplasm (Young's moduli, viscosities, and relaxation times) of the cells are also measured using Digital Image Correlation (DIC) and shear assay techniques. Read More

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Proteome profiling reveals the efficacy and targets of sophocarpine against asthma.

Int Immunopharmacol 2021 Apr 12;96:107348. Epub 2021 Apr 12.

Shaanxi Academy of Traditional Chinese Medicine (Shaanxi Traditional Chinese Medicine Hospital), Xi'an 710003, PR China. Electronic address:

Sophocarpine (SPC) as a quinolizidine alkaloid displays powerful effects on inflammatory diseases through regulating multiple targets. Asthma is a complex heterogeneous and inflammatory disease with an increasing incidence worldwide. Here we established a mice asthma model and investigated the effect of SPC. Read More

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Piperazine-2,5-dione derivatives and an α-pyrone polyketide from Penicillium griseofulvum and their immunosuppression activity.

Phytochemistry 2021 Apr 12;186:112708. Epub 2021 Apr 12.

Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China. Electronic address:

Four undescribed piperazine-2,5-dione derivatives designated janthinolides C-F, and an α-pyrone-containing polyketide namely trichopyrone C, were isolated from the extract of the fungus Penicillium griseofulvum along with four known products. Among them, janthinolide C represents the first naturally occured piperazine-2,5-dione analogue featuring a cleavaged piperazinedione ring with an oxime group, while the structure of janthinolide D possesses a rare N-methoxy group in natural products. Their structures and absolute stereochemistry were elucidated based on spectroscopic data, theoretical NMR and ECD calculations, Snatzke's method, and modified Mosher's method. Read More

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Ximaoglaucumins A - F, new cembranoids with anti-inflammatory activities from the South China Sea soft coral Sarcophyton glaucum.

Bioorg Med Chem 2021 Apr 2;38:116139. Epub 2021 Apr 2.

School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China; State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555, Zu Chong Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, China. Electronic address:

Six new cembrane-type diterpenoids, namely ximaoglaucumins A-F (1-6), along with fifteen known related ones (7-10 and 14-24), have been isolated from the soft coral Sarcophyton glaucum collected off the Ximao Island in the South China Sea. Their structures, including absolute stereochemistry, were elucidated by extensive spectroscopic analysis, quantum mechanical nuclear magnetic resonance (QM-NMR) methods, X-ray diffraction analysis, chemical methods, as well as comparison with the reported data in the literature. Further, detailed analysis of spectroscopic data of 7 not only clarified the confusions regarding 7, 11 (sarcophytolol) and 12/13 (sarcotrocheliol) in the literature, but also led to revise the structure of 11, which was mis-assigned due to careless/erroneous interpretation of the 2D NMR spectra, and to correct the structures of 12/13, which were both wrongly depicted. Read More

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Combining phenolic grafting and laccase-catalyzed cross-linking: Effects on structures, technofunctional properties and human immunoglobulin E binding capacity of egg white proteins.

Food Chem 2021 Mar 13;355:129587. Epub 2021 Mar 13.

Department of Biocatalysis, Institute of Catalysis and Petrochemistry CSIC, Campus UAM, 28049 Madrid, Spain.

The efficiency of laccase-catalyzed protein cross-linking can be impacted by substrate protein structure and competing reactions. In this study, chemical grafting of ferulic acid (FA) on protein surface was applied to modulate the cross-linking of two inflexible globular proteins, lysozyme (LZM) and ovalbumin (OVA). The extent of FA-grafting was positively correlated with protein cross-linking extent, and determined the molecular weight profile and structures of the cross-linked product. Read More

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BSEResU-Net: An attention-based before-activation residual U-Net for retinal vessel segmentation.

Comput Methods Programs Biomed 2021 Apr 1;205:106070. Epub 2021 Apr 1.

Centre of Intelligent Acoustics and Immersive Communications, School of Marine Science and Technology, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P.R. China. Electronic address:

Background And Objectives: Retinal vessels are a major feature used for the physician to diagnose many retinal diseases, such as cardiovascular disease and Glaucoma. Therefore, the designing of an auto-segmentation algorithm for retinal vessel draw great attention in medical field. Recently, deep learning methods, especially convolutional neural networks (CNNs) show extraordinary potential for the task of vessel segmentation. Read More

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Previously identified and unidentified polybrominated biphenyl congeners in serum from people living in an electronic waste dismantling area in China.

Chemosphere 2021 Apr 8;279:130478. Epub 2021 Apr 8.

College of Life and Environmental Sciences, Minzu University of China, Beijing, 100081, China; Engineering Research Center of Food Environment and Public Health, Beijing, 100081, China. Electronic address:

The effects of polybrominated biphenyls (PBBs) on human health have previously attracted much attention, but recent studies of PBBs have been focused on BB-153 and a few other congeners. PBB concentrations in serum samples from residents of an area containing an electronic waste dismantling site were determined in this study. The total PBB concentrations (i. Read More

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STED and parallelized RESOLFT optical nanoscopy of the tubular endoplasmic reticulum and its mitochondrial contacts in neuronal cells.

Neurobiol Dis 2021 Apr 12:105361. Epub 2021 Apr 12.

Department of Applied Physics and Science for Life Laboratory, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden. Electronic address:

The classic view of organelle cell biology is undergoing a constant revision fueled by the new insights unraveled by fluorescence nanoscopy, which enable sensitive, faster and gentler observation of specific proteins in situ. The endoplasmic reticulum (ER) is one of the most challenging structure to capture due the rapid and constant restructuring of fine sheets and tubules across the full 3D cell volume. Here we apply STED and parallelized 2D and 3D RESOLFT live imaging to uncover the tubular ER organization in the fine processes of neuronal cells with focus on mitochondria-ER contacts, which recently gained medical attention due to their role in neurodegeneration. Read More

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Further new nardosinane-type sesquiterpenoids from the Xisha soft coral Litophyton nigrum.

Fitoterapia 2021 Apr 12:104906. Epub 2021 Apr 12.

State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, China. Electronic address:

Further chemical investigation of the Xisha soft coral Litophyton nigrum has resulted in the isolation of four new nardosinane-type sesquiterpenoids, namely linardosinenes D-G (1-4). The structures of new compounds were elucidated by extensive analyses of their spectroscopic data and by comparison with the reported data of known related ones. All compounds exhibited weak inhibitory effect against bromodomain-containing protein 4 (BRD4), a promising therapeutic target in various human diseases, at a concentration of 10 μM. Read More

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A regional and cellular analysis of the early intracellular and extracellular accumulation of Aβ in the brain of 5XFAD mice.

Neurosci Lett 2021 Apr 12:135869. Epub 2021 Apr 12.

Department of Biomedical, Metabolic and Neural Sciences, Center for Neuroscience and Neurotechnology (CfNN), University of Modena and Reggio Emilia, 41125, Modena, Italy. Electronic address:

Intracellular Aβ (iAβ) expression, extracellular Aβ (eAβ) plaque formation and microglial reactivity are characteristic neuropathological events of Alzheimer's disease (AD) and have been detected in several transgenic mouse models of this disease. In this work we decided to investigate the early (2-7 months of age) development of these phenomena at both regional and cellular levels in 5XFAD mice, a severe transgenic mouse model of AD. We demonstrated that 1) Aβ pathology develops in many but not all brain regions, 2) iAβ is transient and almost always followed by eAβ in grey matter regions, and the respective levels are roughly proportional, and 3) in about 1/3 of the grey matter regions with Aβ pathology and in several white matter regions, eAβ plaques can appear where no iAβ-positive structures were detected. Read More

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Evolution of eukaryotes as a story of survival and growth of mitochondrial DNA over two billion years.

Abhijit Deonath

Biosystems 2021 Apr 12:104426. Epub 2021 Apr 12.

Department of Agriculture, Water and the Environment, Australian Government, Canberra, Australia. Electronic address:

Mitochondria's significance in human diseases and in functioning, health and death of eukaryotic cell has been acknowledged widely. Yet our perspective in cell biology and evolution remains nucleocentric. Mitochondrial DNA, by virtue of its omnipresence and species-level conservation, is used as a barcode in animal taxonomy. Read More

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Comparative study on the structures of intra- and extra-cellular polysaccharides from Penicillium oxalicum and their inhibitory effects on galectins.

Int J Biol Macromol 2021 Apr 12. Epub 2021 Apr 12.

Engineering Research Center of Glycoconjugates Ministry of Education, Jilin Provincial Key Laboratory of Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China. Electronic address:

Here, we compare the content and composition of polysaccharides derived from the mycelium (40.4 kDa intracellular polysaccharide, IPS) and culture (27.2 kDa extracellular polysaccharide, EPS) of Penicillium oxalicum. Read More

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Reoperative Total Arch Repair Using a Trifurcated Graft and Selective Antegrade Cerebral Perfusion.

Ann Thorac Surg 2021 Apr 12. Epub 2021 Apr 12.

Division of Cardiothoracic Surgery, Department of Surgery, Westchester Medical Center, New York Medical College, Valhalla, NY.

Background: This study reviews the outcomes of our reoperative total arch repair (TAR) technique using a trifurcated graft and selective antegrade cerebral perfusion (SACP).

Methods: Fifty patients underwent reoperative TAR from January 2005 to September 2020, with either a one-stage (N=9), or two-stage repair (N=41). The two-stage technique includes minimal dissection of the mediastinal structures, an arch-first technique using a trifurcated graft, and construction of a classical elephant trunk via a partial transverse incision distally in the old-graft or in the aorta just distal to the old graft. Read More

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MD simulations reveal the basis for dynamic assembly of Hfq-RNA complexes.

J Biol Chem 2021 Apr 12:100656. Epub 2021 Apr 12.

Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, 135, 612 65, Brno, Czech Republic.

The conserved protein Hfq is a key factor in the RNA-mediated control of gene expression in most known bacteria. The transient intermediates Hfq forms with RNA support intricate and robust regulatory networks. In Pseudomonas, Hfq recognizes repeats of ARN (A-purine-anybase) in target mRNAs via its distal binding side, and together with the Crc protein, assembles into a translation-repression complex. Read More

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Molecular basis for diaryldiamine selectivity and competition with tRNA in a type-2 methionyl-tRNA synthetase from a Gram-negative bacterium.

J Biol Chem 2021 Apr 12:100658. Epub 2021 Apr 12.

Brazilian Biosciences National Laboratory (LNBio), Brazilian Centre for Research in Energy and Materials (CNPEM), CEP 13083-100, Campinas, SP, Brazil. Electronic address:

Gram-negative bacteria are responsible for a variety of human, animal and plant diseases. The spread of multidrug-resistant Gram-negative bacteria poses a challenge to disease control and highlights the need for novel antimicrobials. Due to their critical role in protein synthesis, aminoacyl-tRNA synthetases (AaRS), including the methionyl-tRNA synthetases MetRS1 and MetRS2, are attractive drug targets. Read More

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CDKL kinase regulates the length of the ciliary proximal segment.

Curr Biol 2021 Apr 8. Epub 2021 Apr 8.

Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada; Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada. Electronic address:

Cilia are organelles found throughout most unicellular eukaryotes and different metazoan cell types. To accomplish their essential roles in cell motility, fluid flow, and signaling, cilia are divided into subcompartments with variable structures, compositions, and functions. How these specific subcompartments are built remains almost completely unexplored. Read More

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Variable kinship patterns in Neolithic Anatolia revealed by ancient genomes.

Curr Biol 2021 Apr 6. Epub 2021 Apr 6.

Department of Biological Sciences, Middle East Technical University (METU), Ankara, Turkey. Electronic address:

The social organization of the first fully sedentary societies that emerged during the Neolithic period in Southwest Asia remains enigmatic, mainly because material culture studies provide limited insight into this issue. However, because Neolithic Anatolian communities often buried their dead beneath domestic buildings, household composition and social structure can be studied through these human remains. Here, we describe genetic relatedness among co-burials associated with domestic buildings in Neolithic Anatolia using 59 ancient genomes, including 22 new genomes from Aşıklı Höyük and Çatalhöyük. Read More

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Three-in-One Strategy Constructing a Series of Hybrid Tetrahedral Motif-Based Selenides with Balanced Second-Order Nonlinear Optical Performance.

Inorg Chem 2021 Apr 15. Epub 2021 Apr 15.

School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, P.R. China.

Concurrently achieving suitable second harmonic generation (SHG) effect and high laser-induced damage threshold (LIDT) is challenging for infrared nonlinear optical (NLO) materials. Here, a series of pentanary infrared NLO materials CsMMSnSe (M = Ga, In; M = Si, Ge) have been obtained by a three-in-one strategy, . three kinds of elements (M, M, and Sn) in one position, which is first adopted to design NLO materials. Read More

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Mtr4 RNA helicase structures and interactions.

Biol Chem 2021 Apr 6;402(5):605-616. Epub 2021 Jan 6.

Department of Chemistry and Biochemistry, Utah State University, Logan, UT84322-0300, USA.

Mtr4 is a Ski2-like RNA helicase that plays a central role in RNA surveillance and degradation pathways as an activator of the RNA exosome. Multiple crystallographic and cryo-EM studies over the past 10 years have revealed important insight into the Mtr4 structure and interactions with protein and nucleic acid binding partners. These structures place Mtr4 at the center of a dynamic process that recruits RNA substrates and presents them to the exosome. Read More

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Transcription, translation, and DNA repair: new insights from emerging noncanonical substrates of RNA helicases.

Biol Chem 2021 Apr 14;402(5):637-644. Epub 2020 Dec 14.

Department of Biochemistry, Purdue University, BCHM A343, 175 S. University Street, West Lafayette, IN, 47907, USA.

RNA helicases are enzymes that exist in all domains of life whose canonical functions include ATP-dependent remodeling of RNA structures and displacement of proteins from ribonucleoprotein complexes (RNPs). These enzymes play roles in virtually all processes of RNA metabolism, including pre-mRNA splicing, rRNA processing, nuclear mRNA export, translation and RNA decay. Here we review emerging noncanonical substrates of RNA helicases including RNA-DNA hybrids (R-loops) and RNA and DNA G-quadruplexes and discuss their biological significance. Read More

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The DHX36-specific-motif (DSM) enhances specificity by accelerating recruitment of DNA G-quadruplex structures.

Biol Chem 2021 Apr 16;402(5):593-604. Epub 2020 Dec 16.

Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX78712, USA.

DHX36 is a eukaryotic DEAH/RHA family helicase that disrupts G-quadruplex structures (G4s) with high specificity, contributing to regulatory roles of G4s. Here we used a DHX36 truncation to examine the roles of the 13-amino acid DHX36-specific motif (DSM) in DNA G4 recognition and disruption. We found that the DSM promotes G4 recognition and specificity by increasing the G4 binding rate of DHX36 without affecting the dissociation rate. Read More

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Highly Stable Single Crystals of Three-Dimensional Porous Oligomer Frameworks Synthesized under Kinetic Conditions.

Angew Chem Int Ed Engl 2021 Apr 15. Epub 2021 Apr 15.

University of North Texas, Department of Chemistry, 1508 W Mulberry St, 76201, Denton, UNITED STATES.

Herein, various robust, crystalline, and porous organic frameworks based on in-situ-formed imine-linked oligomers were investigated; these oligomers self-assembled through collaborative intermolecular hydrogen bonding interactions via liquid-liquid interfacial reactions. The soluble oligomers were kinetic products with multiple unreacted aldehyde groups that acted as hydrogen bond donors and acceptors and directed the assembly of the resulting oligomers into three-dimensional frameworks. The sequential formation of robust covalent linkages and highly reversible hydrogen bonds enforced long-range symmetry and facilitated the production of large single crystals, with structures that were unambiguously determined and refined based on high-quality single-crystal X-ray diffraction data. Read More

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A Vibration-Induced Emision-Based Fluorescent Chemosensor for the Selective and Visual Recognition of Glucose.

Angew Chem Int Ed Engl 2021 Apr 15. Epub 2021 Apr 15.

University of Bristol, School of Chemistry, Cantock's Close, BS8 1TS, Bristol, UNITED KINGDOM.

The development of chemosensors to detect analytes in biologically relevant solutions is a challenging task . We report the synthesis of a fluorescent receptor that combines  vibration-induced emission (VIE) and dynamic covalent chemistry for the detection of glucose in aqueous media. We  show that  the bis- 2-( N -methylaminomethyl) phenylboronic acid-decorated  N , N '-diphenyl-dihydrodibenzo[ a , c ]phenazine  (DPAC)  receptor  1  can detect glucose and discriminat e between closely related monosaccharides including those commonly found in blood. Read More

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New pectic polysaccharides from Codonopsis pilosula and C. tangshen: structural characterization and cellular antioxidant activities.

J Sci Food Agric 2021 Apr 15. Epub 2021 Apr 15.

Natural Medicine Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China.

Background: Codonopsis pilosula and C. tangshen are plants widely used in traditional Chinese medicine. Two pectic polysaccharides from roots of C. Read More

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