16 research outputs found

    Pectin Alleviates High Fat (Lard) Diet-Induced Nonalcoholic Fatty Liver Disease in Mice: Possible Role of Short-Chain Fatty Acids and Gut Microbiota Regulated by Pectin

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    Consumption of pectin contributes to changes in the gut microbiota and the metabolism of short-chain fatty acids (SCFAs). We aimed to investigate the effects of and mechanism by which pectin prevented nonalcoholic fatty liver disease (NAFLD) in mice that were fed a high-fat diet containing 30% lard (HF). HF-fed mice that orally ingested pectin for 8 weeks exhibited improvements in lipid metabolism and decreased oxidative stress and inflammation through a mechanism regulated by the mitogen-activated protein kinase pathway. Pectin dose-dependently generated an increase in acetic acid (from 566.4 ± 26.6 to 694.6 ± 35.9 μmol/mL, <i>p</i> < 0.05) and propionic acid (from 474.1 ± 84.3 to 887.0 ± 184.7 μmol/mL, <i>p</i> < 0.05) contents and significantly increased the relative abundance of Bacteroides (from 0.27% to 11.6%), Parabacteroides (from 3.9‰ to 5.3%), Olsenella (from 2.9‰ to 1.3%), and Bifidobacterium (from 0.03% to 1.9%) in the gut of HF-fed mice. Intestinal microbiota and SCFAs may thus contribute to the well-established link between pectin consumption and NAFLD

    One-Pot Synthesis of Pyrrolo­[3,2,1-<i>kl</i>]pheno­thiazines through Copper-Catalyzed Tandem Coupling/Double Cyclization Reaction

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    A novel and efficient synthesis of pyrrolo­[3,2,1-<i>kl</i>]­pheno­thiazines has been developed through a Cu­(I)-catalyzed tandem C–S coupling/double cyclization process. Using 2-alkynyl-6-iodoanilines and <i>o</i>-bromo­benzenethiols as the starting materials, a wide range of pyrrolo­[3,2,1-<i>kl</i>]­pheno­thiazine derivatives were facilely and efficiently generated in one pot under Cu­(I) catalysis

    Physiologically Relevant Changes in Serotonin Resolved by Fast Microdialysis

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    Online microdialysis is a sampling and detection method that enables continuous interrogation of extracellular molecules in freely moving subjects under behaviorally relevant conditions. A majority of recent publications using brain microdialysis in rodents report sample collection times of 20–30 min. These long sampling times are due, in part, to limitations in the detection sensitivity of high performance liquid chromatography (HPLC). By optimizing separation and detection conditions, we decreased the retention time of serotonin to 2.5 min and the detection threshold to 0.8 fmol. Sampling times were consequently reduced from 20 to 3 min per sample for online detection of serotonin (and dopamine) in brain dialysates using a commercial HPLC system. We developed a strategy to collect and to analyze dialysate samples continuously from two animals in tandem using the same instrument. Improvements in temporal resolution enabled elucidation of rapid changes in extracellular serotonin levels associated with mild stress and circadian rhythms. These dynamics would be difficult or impossible to differentiate using conventional microdialysis sampling rates

    Three-Dimensional Conductive Gel Network as an Effective Binder for High-Performance Si Electrodes in Lithium-Ion Batteries

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    Silicon (Si) has been widely investigated as a candidate for lithium-ion batteries (LIBs) due to its extremely high specific capacity. The binders play a key role in fabricating high-performance Si electrodes which usually suffer from the huge volume expansion associated with the alloying and dealloying processes. Here we develop a facile route to prepare a three-dimensional (3D) conductive interpenetrated gel network as a novel binder for high-performance Si anodes through chemically cross-linking of acrylic acid monomer followed by the in situ polymerization of aniline. The excellent electrical conductivity, strong mechanical adhesion and high electrolyte uptake render the conductive gel network a potential binder for high-performance Si anodes. The resultant Si anodes exhibit excellent cycling stability, high Coulombic efficiency and superior rate capability, revealing better electrochemical properties compared to the Si anodes with conventional binders. The 3D conductive gel binder could not only accommodate the volume expansion and maintain electric connectivity, but also assist in the formation of stable solid electrolyte interphase (SEI) films. Such a strategy sheds light on the design of polymer binders in LIBs, especially for high-capacity electrode materials with huge volume changes during long-term cycling

    Quasi-Layer-by-Layer Growth of Pentacene on HOPG and Au Surfaces

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    High-resolution scanning tunneling microscopy (STM) is a promising method for characterizing organic semiconductors to obtain a deep understanding of organic semiconductor physics. However, organic films on conductive single-crystal substrates, which are required for STM, usually present different growth behaviors than the films on inert substrates such as SiO<sub>2</sub>. Here, we reported a simple modification method for modulating the organic semiconductor film growth on the highly oriented pyrolytic graphite (HOPG) and Au(111) substrates and investigated the detailed morphology evolution. Self-assembled monolayers (SAMs) fabricated from vacuum deposition and solution processing were introduced on these conductive substrates. Pentacene, a prototypical organic semiconductor, presented quasi-layer-by-layer growth on HOPG or Au(111) sufaces modified with solution-processed alkane monolayer. The pentacene film resembled the upright packing and terraced morphology but with larger grain size than that of thin-film phase on SiO<sub>2</sub>. The introduced <i>n</i>-dotriacontane layer decreased the interaction between pentacene adsorbates and the active substrate and provided a lower surface energy which supported the upright orientation of pentacene. Modification of the substrates with alkanes provides a feasible approach to grow high-quality organic thin films that are suitable for characterization down to the molecular level. Additionally, this approach is effective for two-dimensional substrate materials such as graphene and is not limited to single-crystal substrates

    Small-Molecule Patterning via Prefunctionalized Alkanethiols

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    Interactions between small molecules and biomolecules are important physiologically and for biosensing, diagnostic, and therapeutic applications. To investigate these interactions, small molecules can be tethered to substrates through standard coupling chemistries. While convenient, these approaches co-opt one or more of the few small-molecule functional groups needed for biorecognition. Moreover, for multiplexing, individual probes require different surface functionalization chemistries, conditions, and/or protection/deprotection strategies. Thus, when placing multiple small molecules on surfaces, orthogonal chemistries are needed that preserve all functional groups and are sequentially compatible. Alternately, we approach high-fidelity small-molecule patterning by coupling small-molecule neurotransmitter precursors, as examples, to monodisperse asymmetric oligo­(ethylene glycol)­alkanethiols during synthesis and prior to self-assembly on Au substrates. We use chemical lift-off lithography to singly and doubly pattern substrates. Selective antibody recognition of prefunctionalized thiols was comparable to or better than recognition of small molecules functionalized to alkanethiols after surface assembly. These findings demonstrate that synthesis and patterning approaches that circumvent sequential surface conjugation chemistries enable biomolecule recognition and afford gateways to multiplexed small-molecule functionalized substrates

    Controlled DNA Patterning by Chemical Lift-Off Lithography: Matrix Matters

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    Nucleotide arrays require controlled surface densities and minimal nucleotide–substrate interactions to enable highly specific and efficient recognition by corresponding targets. We investigated chemical lift-off lithography with hydroxyl- and oligo(ethylene glycol)-terminated alkanethiol self-assembled monolayers as a means to produce substrates optimized for tethered DNA insertion into post-lift-off regions. Residual alkanethiols in the patterned regions after lift-off lithography enabled the formation of patterned DNA monolayers that favored hybridization with target DNA. Nucleotide densities were tunable by altering surface chemistries and alkanethiol ratios prior to lift-off. Lithography-induced conformational changes in oligo(ethylene glycol)-terminated monolayers hindered nucleotide insertion but could be used to advantage <i>via</i> mixed monolayers or double-lift-off lithography. Compared to thiolated DNA self-assembly alone or with alkanethiol backfilling, preparation of functional nucleotide arrays by chemical lift-off lithography enables superior hybridization efficiency and tunability

    Advancing Biocapture Substrates via Chemical Lift-Off Lithography

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    Creating small-molecule-functionalized platforms for high-throughput screening or biosensing applications requires precise placement of probes on solid substrates and the ability to capture and to sort targets from multicomponent samples. Here, chemical lift-off lithography was used to fabricate large-area, high-fidelity patterns of small-molecule probes. Lift-off lithography enables biotin–streptavidin patterned recognition with feature sizes ranging from micrometers to below 30 nm. Subtractive patterning via lift-off facilitated insertion of a different type of molecule and, thus, multiplexed side-by-side placement of small-molecule probes such that binding partners were directed to cognate probes from solution. Small molecules mimicking endogenous neurotransmitters were patterned using lift-off lithography to capture native membrane-associated receptors. We characterized patterning of alkanethiols that self-assemble on Au having different terminal functional groups to expand the library of molecules amenable to lift-off lithography enabling a wide range of functionalization chemistries for use with this simple and versatile patterning method

    A Chinese version of the Language Screening Test (CLAST) for early-stage stroke patients

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    <div><p>There is a severe lack of aphasia screening tools for bedside use in Chinese. A number of aphasia assessment tools have recently been developed abroad, but some of these scales were not suitable for patients with acute stroke. The Language Screening Test (which includes two parallel versions [a/b]) in French has been proven to be an effective and time-saving aphasia screening scale for early-stage stroke patients. Therefore, we worked out a Chinese version of the LAST taking into consideration Chinese language and culture. Two preliminary parallel versions (a/b) were tested on 154 patients with stroke at acute phase and 107 patients with stroke at non-acute phase, with the Western Aphasia Battery serving as a gold standard. The equivalence between the two parallel versions and the reliability/validity of each version were assessed. The median time to complete one preliminary Chinese version (each had some item redundancy) was 98 seconds. Two final parallel versions were established after adjustment/elimination of the redundant items and were found to be equivalent (intra-class correlation coefficient: 0.991). Internal consistency is(Cronbach α for each version [a/b] was 0.956 and 0.965, respectively) good. Internal validity was fine: (a) no floor or ceiling effect/item redundancy; (b) construct validity revealed a 1-dimension structure, just like the French version. The higher educated subjects scored higher than their lower educated counterparts (<i>p<0</i>.<i>01</i>). The external validity: at the optimum cut-off point where the score of version a/b <14 in higher educated group(<13 in lower): the specificity of each version was 0.878/0.902(1/1 in lower) and sensitivity was 0.972/0.944(0.944/0.944 in lower). Inter-rater equivalence (intra-class correlation coefficient) was 1. The Chinese version of the Language Screening Test was proved to be an efficient and time-saving bedside aphasia screening tool for stroke patients at acute phase and can be used by an average medical physician.</p></div
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