59 research outputs found

    Complexity measures and uncertainty relations of the high-dimensional harmonic and hydrogenic systems

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    In this work we find that not only the Heisenberg-like uncertainty products and the R\'enyi-entropy-based uncertainty sum have the same first-order values for all the quantum states of the DD-dimensional hydrogenic and oscillator-like systems, respectively, in the pseudoclassical (DD \to \infty) limit but a similar phenomenon also happens for both the Fisher-information-based uncertainty product and the Shannon-entropy-based uncertainty sum, as well as for the Cr\'amer-Rao and Fisher-Shannon complexities. Moreover, we show that the LMC (L\'opez-Ruiz-Mancini-Calvet) and LMC-R\'enyi complexity measures capture the hydrogenic-harmonic difference in the high dimensional limit already at first order

    Synthesis of Tetrafluorinated Aromatic Amino Acids with Distinct Signatures in <sup>19</sup>F NMR

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    Fluorinated amino acids serve as powerful tools in protein chemistry. We synthesized a series of <i>para</i>-substituted tetrafluorophenylalanines via the regioselective S<sub>NAr</sub> chemistry of the commercially available pentafluorophenylalanine Boc-Z. These novel unnatural amino acids display distinct <sup>19</sup>F NMR signatures, making them powerful tools for analyzing protein–membrane interactions with NMR spectroscopy

    Fast Diazaborine Formation of Semicarbazide Enables Facile Labeling of Bacterial Pathogens

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    Bioorthogonal conjugation chemistry has enabled the development of tools for the interrogation of complex biological systems. Although a number of bioorthogonal reactions have been documented in literature, they are less ideal for one or several reasons including slow kinetics, low stability of the conjugated product, requirement of toxic catalysts, and side reactions with unintended biomolecules. Herein we report a fast (>10<sup>3</sup> M<sup>–1</sup> s<sup>–1</sup>) and bioorthogonal conjugation reaction that joins semicarbazide to an aryl ketone or aldehyde with an <i>ortho</i>-boronic acid substituent. The boronic acid moiety greatly accelerates the initial formation of a semicarbazone conjugate, which rearranges into a stable diazaborine. The diazaborine formation can be performed in blood serum or cell lysates with minimal interference from biomolecules. We further demonstrate that application of this conjugation chemistry enables facile labeling of bacteria. A synthetic amino acid D-AB3, which presents a 2-acetylphenylboronic acid moiety as its side chain, was found to incorporate into several bacterial species through cell wall remodeling, with particularly high efficiency for <i>Escherichia coli</i>. Subsequent D-AB3 conjugation to a fluorophore-labeled semicarbazide allows robust detection of this bacterial pathogen in blood serum

    Fast Diazaborine Formation of Semicarbazide Enables Facile Labeling of Bacterial Pathogens

    No full text
    Bioorthogonal conjugation chemistry has enabled the development of tools for the interrogation of complex biological systems. Although a number of bioorthogonal reactions have been documented in literature, they are less ideal for one or several reasons including slow kinetics, low stability of the conjugated product, requirement of toxic catalysts, and side reactions with unintended biomolecules. Herein we report a fast (>10<sup>3</sup> M<sup>–1</sup> s<sup>–1</sup>) and bioorthogonal conjugation reaction that joins semicarbazide to an aryl ketone or aldehyde with an <i>ortho</i>-boronic acid substituent. The boronic acid moiety greatly accelerates the initial formation of a semicarbazone conjugate, which rearranges into a stable diazaborine. The diazaborine formation can be performed in blood serum or cell lysates with minimal interference from biomolecules. We further demonstrate that application of this conjugation chemistry enables facile labeling of bacteria. A synthetic amino acid D-AB3, which presents a 2-acetylphenylboronic acid moiety as its side chain, was found to incorporate into several bacterial species through cell wall remodeling, with particularly high efficiency for <i>Escherichia coli</i>. Subsequent D-AB3 conjugation to a fluorophore-labeled semicarbazide allows robust detection of this bacterial pathogen in blood serum

    Dynamic Formation of Imidazolidino Boronate Enables Design of Cysteine-Responsive Peptides

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    We describe the dynamic and chemoselective conjugation between 2-formylphenylboronic acid and l-2,3-diaminopropionic acid yielding an imidazolidino boronate (IzB) complex. The IzB complex formation readily proceeds in biological milieu with little interference by common biomolecules except cysteine. We demonstrate the potential of this reversible conjugation for biological applications by creating “smart” peptides that specifically respond to cysteine in complex biological media. Specifically, the design and characterization of a fluorogenic sensor of cysteine is described

    Photoinduced Oscillations and Pulse Waves in the Hydrogen Peroxide–Sulfite–Ferrocyanide Reaction

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    The hydrogen peroxide–sulfite–ferrocyanide reaction shows excellent photosensitivity under pulse light illumination, which can be used to efficiently control the spatiotemporal dynamics of the nonlinear chemical system. Here, we numerically simulated the photoinduced pH oscillations by integrating two models that describe the oscillatory and photosensitive behaviors, respectively. A dynamic transition from the low-pH steady state to oscillations can be obtained using light illumination. In accordance with the simulation results, oscillatory dynamics was experimentally obtained under light illumination through excitation of a low-pH steady state. In the reaction–diffusion medium, corresponding multiple pulse waves were observed under suitable acid concentration and illumination conditions. Hence, light illumination can be efficiently employed to tune pattern formation in pH dynamic systems. Especially, the observation indicates that the local oscillations and pulse waves were promoted by diffusion in the gel reactor when comparing with dynamics in a homogeneous system

    Photoinduced Oscillations and Pulse Waves in the Hydrogen Peroxide–Sulfite–Ferrocyanide Reaction

    No full text
    The hydrogen peroxide–sulfite–ferrocyanide reaction shows excellent photosensitivity under pulse light illumination, which can be used to efficiently control the spatiotemporal dynamics of the nonlinear chemical system. Here, we numerically simulated the photoinduced pH oscillations by integrating two models that describe the oscillatory and photosensitive behaviors, respectively. A dynamic transition from the low-pH steady state to oscillations can be obtained using light illumination. In accordance with the simulation results, oscillatory dynamics was experimentally obtained under light illumination through excitation of a low-pH steady state. In the reaction–diffusion medium, corresponding multiple pulse waves were observed under suitable acid concentration and illumination conditions. Hence, light illumination can be efficiently employed to tune pattern formation in pH dynamic systems. Especially, the observation indicates that the local oscillations and pulse waves were promoted by diffusion in the gel reactor when comparing with dynamics in a homogeneous system

    An equity analysis of health examination service utilization by women from underdeveloped areas in western China

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    <div><p>Objective</p><p>This study sought to examine the sources of inequity in health examination service utilization by women from underdeveloped areas in western China.</p><p>Methods</p><p>Based on data from the 5<sup>th</sup> National Health Service Survey in Shaanxi province, women’s utilization of health examination services was examined according to gynecological, cervical smear, and breast examination rates. The equity of health examination service utilization by 15- to 64-year-old women and the factors contributing to inequity were determined using the health concentration index, decomposition of the concentration index, and the horizontal inequity index.</p><p>Results</p><p>The examination rates for gynecological, cervical smear, and breast exams for 15- to 64-year-old women in Shaanxi province were 40.61%, 27.08%, and 24.59%, respectively. The horizontal inequity indices of gynecological, cervical smear, and breast examination rates were 0.0480, 0.0423, and 0.0764, respectively, and each examination rate was higher for wealthy individuals. The contribution rates of economic status to the inequalities in gynecological, cervical smear, and breast examination rates were 65.80%, 74.31%, and 56.49%, respectively. The contribution rates of educational status to the inequalities in gynecological, cervical smear, and breast examination rates were 21.01%, 14.83% and 30.00%, respectively. The contribution rates of age to the inequalities in gynecological, cervical smear, and breast examination rates were 25.77%, 26.55%, and 18.40%, respectively.</p><p>Conclusions</p><p>Women’s health examination rates differed between populations with different socio-demographic characteristics. There is pro-wealth inequality in each examination rate. This study found that financial status, age, and education level were the main reasons for the unequal utilization of health examination services.</p></div
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