13 research outputs found

    Marangoni Effect-Driven Motion of Miniature Robots and Generation of Electricity on Water

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    The well-known Marangoni effect perfectly supports the dynamic mechanism of organic solvent-swollen gels on water. On this basis, we report a series of energy conversion processes of concentrated droplets of polyvinylidene fluoride/dimethyl formamide (PVDF/DMF) that can transfer chemical-free energy to kinetic energy to rapidly rotate itself on water. This droplet (22.2 mg) is capable to offer kinetic energy of 0.099 μJ to propel an artificial paper rocket of 31.8 mg to move over 560 cm on water at an initial velocity of 7.9 cm s<sup>–1</sup>. As the droplet increases to 35.0 mg, a paper goldfish of 10.6 mg can be driven to swim longer at a higher initial velocity of 20 cm s<sup>–1</sup>. The kinetic energy of the droplet can be further converted to electrical energy through an electromagnetic generator, in which as a 0.5 MΩ resistor is loaded, the peak output reaches 6.5 mV that corresponds to the power density of 0.293 μW kg<sup>–1</sup>. We believe that this report would open up a promising avenue to exploit energies for applications in miniature robotics

    Marangoni Effect-Driven Motion of Miniature Robots and Generation of Electricity on Water

    No full text
    The well-known Marangoni effect perfectly supports the dynamic mechanism of organic solvent-swollen gels on water. On this basis, we report a series of energy conversion processes of concentrated droplets of polyvinylidene fluoride/dimethyl formamide (PVDF/DMF) that can transfer chemical-free energy to kinetic energy to rapidly rotate itself on water. This droplet (22.2 mg) is capable to offer kinetic energy of 0.099 μJ to propel an artificial paper rocket of 31.8 mg to move over 560 cm on water at an initial velocity of 7.9 cm s<sup>–1</sup>. As the droplet increases to 35.0 mg, a paper goldfish of 10.6 mg can be driven to swim longer at a higher initial velocity of 20 cm s<sup>–1</sup>. The kinetic energy of the droplet can be further converted to electrical energy through an electromagnetic generator, in which as a 0.5 MΩ resistor is loaded, the peak output reaches 6.5 mV that corresponds to the power density of 0.293 μW kg<sup>–1</sup>. We believe that this report would open up a promising avenue to exploit energies for applications in miniature robotics

    Easy Synthesis of Hierarchical Carbon Spheres with Superior Capacitive Performance in Supercapacitors

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    An easy template-free approach to the fabrication of pure carbon microspheres has been achieved via direct pyrolysis of as-prepared polyaromatic hydrocarbons including polynaphthalene and polypyrene. The polyaromatics were synthesized from aromatic hydrocarbons (AHCs) using anhydrous zinc chloride as the Friedel–Crafts catalyst and chloromethyl methyl ether as a cross-linker. The experimental results show that the methylene bridges between phenyl rings generate a hierarchical porous polyaromatic precursor to form three-dimensionally (3D) interconnected micro-, meso-, and macroporous networks during carbonization. These hierarchical porous carbon aggregates of spherical carbon spheres exhibit faster ion transport/diffusion behavior and increased surface area usage in electric double-layer capacitors. Furthermore, micropores are present in the 3D interconnected network inside the cross-linked AHC-based carbon microspheres, thus imparting an exceptionally large, electrochemically accessible surface area for charge accumulation

    Self-Assembly of Morphology-Tunable Architectures from Tetraarylmethane Derivatives for Targeted Drug Delivery

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    Tetraarylmethane compounds consisting of two pyrogallol and two aniline units, namely, Ar<sub>2</sub>CAr′<sub>2</sub> {Ar = 3,4,5-C<sub>6</sub>H<sub>2</sub>(OH)<sub>3</sub> and Ar′ = 3,5-R<sub>2</sub>-4-C<sub>6</sub>H<sub>2</sub>NH<sub>2</sub> [R = Me (<b>1</b>), <i>i</i>Pr (<b>2</b>)]} exhibit excellent self-assembly behavior. Compound <b>1</b> yields size-tunable hollow nanospheres (HNSs) with a narrow size distribution, and <b>2</b> yields various morphologies ranging from microtubules to microrods <i>via</i> self-assembly induced by hydrogen bonding and π–π stacking interactions. On the basis of the experimental results, a plausible mechanism for morphology tunability was proposed. As a means of utilizing the self-assembled HNSs for targeting controlled drug delivery, folic acid (FA) and rhodamine 6G (Rh6G) were grafted onto compound <b>1</b> to yield the FA–Rh6G–<b>1</b> complex. The HNSs fabricated with FA–Rh6G–<b>1</b> showed low cytotoxicity against human embryonic kidney 293T cells and CT26 colon carcinoma cells and good doxorubicin (DOX) loading capacity (9.6 wt %). The FA receptor-mediated endocytosis of FA–Rh6G–<b>1</b> HNSs examined by using a confocal laser scanning microscope and a flow cytometer revealed that the uptake of FA–Rh6G–<b>1</b> HNSs into CT26 cells was induced by FA receptor-mediated endocytosis. <i>In vitro</i> drug delivery tests showed that the DOX molecules were released from the resulting HNSs in a sustainable and pH-dependent manner, demonstrating a potential application for HNSs in targeted drug delivery for cancer therapy

    Examples of the most commonly used functions in SRplot.

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    (A) Cluster heatmap; (B) motif logo; (C) Enrichment GO term (BP/CC/MF); (D) Two tracks circus histogram; (E) SNP density; (F) Enhanced volcano plot; (G) KM survival curve; (H) Circle correlation pearson; (I) Correlation plot.</p

    Outline of functions in SRplot.

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    Graphics are widely used to provide summarization of complex data in scientific publications. Although there are many tools available for drawing graphics, their use is limited by programming skills, costs, and platform specificities. Here, we presented a freely accessible easy-to-use web server named SRplot that integrated more than a hundred of commonly used data visualization and graphing functions together. It can be run easily using all Web browsers and there are no strong requirements on the computing power of users’ machines. With a user-friendly graphical interface, users can simply paste the contents of the input file into the text box according to the defined file format. Modification operations can be easily performed, and graphs can be generated in real-time. The resulting graphs can be easily downloaded in bitmap (PNG or TIFF) or vector (PDF or SVG) format in publication quality. The website is updated promptly and continuously. Functions in SRplot have been improved, optimized and updated depend on feedback and suggestions from users. The graphs prepared with SRplot have been featured in more than five hundred peer-reviewed publications. The SRplot web server is now freely available at http://www.bioinformatics.com.cn/SRplot.</div

    Mitochondrial complex I bridges a connection between regulation of carbon flexibility and gastrointestinal commensalism in the human fungal pathogen <i>Candida albicans</i>

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    <div><p>Efficient assimilation of alternative carbon sources in glucose-limited host niches is critical for colonization of <i>Candida albicans</i>, a commensal yeast that frequently causes opportunistic infection in human. <i>C</i>. <i>albicans</i> evolved mechanistically to regulate alternative carbon assimilation for the promotion of fungal growth and commensalism in mammalian hosts. However, this highly adaptive mechanism that <i>C</i>. <i>albicans</i> employs to cope with alternative carbon assimilation has yet to be clearly understood. Here we identified a novel role of <i>C</i>. <i>albicans</i> mitochondrial complex I (CI) in regulating assimilation of alternative carbon sources such as mannitol. Our data demonstrate that CI dysfunction by deleting the subunit Nuo2 decreases the level of NAD<sup>+</sup>, downregulates the NAD<sup>+</sup>-dependent mannitol dehydrogenase activity, and consequently inhibits hyphal growth and biofilm formation in conditions when the carbon source is mannitol, but not fermentative sugars like glucose. Mannitol-dependent morphogenesis is controlled by a ROS-induced signaling pathway involving Hog1 activation and Brg1 repression. <i>In vivo</i> studies show that <i>nuo2</i>Δ/Δ mutant cells are severely compromised in gastrointestinal colonization and the defect can be rescued by a glucose-rich diet. Thus, our findings unravel a mechanism by which <i>C</i>. <i>albicans</i> regulates carbon flexibility and commensalism. Alternative carbon assimilation might represent a fitness advantage for commensal fungi in successful colonization of host niches.</p></div

    Mannitol-dependent hyphal inhibition in the <i>nuo2</i>Δ/Δ mutant is not majorly due to defective proliferation and increased osmotic potential.

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    <p>(A) Vegetative growth of Wild type, <i>nuo2</i>Δ/Δ and NUO2 AB strains on YEP medium supplemented with 2% of mannitol, glucose or mannose. Cells were grown to mid-log stage (8h of growth; OD<sub>600</sub> = 1.0), serially diluted and displayed on plates. The colonies were photographed after incubation at 30°C for 3 days. (B) Hyphal comparison of indicated strains under normoxic and hypoxic conditions. Strains were initially plated for single colonies on Spider medium and incubated under normoxic or hypoxic (controlled CO<sub>2</sub> incubator; less than 0.2% oxygen) condition in the dark at 37°C. Pictures were taken after 3 days of incubation under normoxic condition and 7 days under hypoxic condition, respectively. (C) Phenotypic assay of Nuo2 including morphology under conditions that YEP medium is supplemented with different combinations of carbon sources and salt. The <i>nuo2</i>Δ/Δ mutant cells were inoculated on YEP medium containing different concentrations of carbon sources in the presence or absence of salt (1M NaCl) and incubated at 37°C. Pictures were taken after 3 h of incubation. (D) Effect of glucose or mannose supplementation on vegetative growth of <i>nuo2</i>Δ/Δ mutant under mannitol condition. Cell cultures (pre-diluted to OD<sub>600</sub> = 0.8) from wild type, <i>nuo2</i>Δ/Δ or NUO2 AB strains were diluted serially in 10 fold increments prior to being spotted onto YEP plates supplemented with different combinations of carbon sources. Plates were incubated at 30°C and pictures were taken after 2 days.</p

    Model for the role of CI activity in mannitol-dependent fungal morphogenesis and gastrointestinal commensalism.

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    <p>Wild type <i>C</i>. <i>albicans</i> enters the glycolysis pathway by converting mannitol to mannose, a step catalyzed by the NAD<sup>+</sup>-dependent mannitol dehydrogenase whose activity is sustained by CI via producing NAD<sup>+</sup>. CI dysfunction by deleting <i>NUO2</i> inhibits hyphal growth, biofilm formation and gastrointestinal commensalism through at least two distinct mechanisms. For the first mechanism, deletion of <i>NUO2</i> blocks the glycolytic pathway by decreasing availability of NAD<sup>+</sup> and therefore inhibits hyphae and biofilm formation through an as yet uncharacterized way. For the second mechanism, cells lacking <i>NUO2</i> produces high levels of ROS which triggers a mannitol-dependent signaling pathway involving Hog1 MAPK activation and Brg1 repression. In consequence, downregulation of HSGs inhibits the hyphal growth and biofilm development in a mannitol-dependent manner. By responding to nutrients available in gastrointestinal tract, <i>C</i>. <i>albicans</i> cells adjust CI activity to coordinate pathways required for hyphal morphogenesis and biofilm development that possibly promotes commensalism.</p
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