34 research outputs found

    Potassium Periodate–Luminol–Silver Nanoparticles as a New Chemiluminescence System and its Application to Detect Fenoterol and Orciprenaline

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    <div><p>In the presence of silver nanoparticles, fenoterol and orciprenaline were shown to enhance the chemiluminescence of the potassium periodate-luminol chemiluminescence system. Therefore, a new method for the determination of fenoterol and orciprenaline was developed. The catalytic effect of silver nanoparticles upon the reaction of potassium periodate and luminol was studied. The chemiluminescence characteristics of potassium periodate, luminal, and silver nanoparticles with fenoterol and orciprenaline were studied. Using univariate design, the factors influencing chemiluminescence were optimized. The optimal experimental conditions were 60 µmol L<sup>−1</sup> of potassium periodate, 80 µmol L<sup>−1</sup> of luminol, 6 mmol L<sup>−1</sup> of sodium hydroxide, 2 µmol L<sup>−1</sup> of silver nanoparticles, and a flow rate of 2.0 mL min<sup>−1</sup>. The system permitted 200 injections per hour. The linear dynamic ranges were between 0.6 and 10 ng mL<sup>−1</sup> for fenoterol and 0.4 and 10 ng mL<sup>−1</sup> for orciprenaline, with limits of detection of 0.1 ng mL<sup>−1</sup> for fenoterol and 0.1 ng mL<sup>−1</sup> for orciprenaline. The method was successfully employed to determine fenoterol and orciprenaline with recoveries in the range of 97.5% to 99.9%. Chemiluminescence reaction mechanisms for these systems were proposed.</p></div

    A New One-Dimensional Spin Chain System Co<sub>3</sub>(BPO<sub>4</sub>)<sub>2</sub>(PO<sub>4</sub>)(OH)<sub>3</sub> Showing 1/3 Magnetization Plateau

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    A new borophosphate Co<sub>3</sub>(BPO<sub>4</sub>)<sub>2</sub>­(PO<sub>4</sub>)­(OH)<sub>3</sub> was synthesized by a conventional hydrothermal method. The titled compound crystallizes in the monoclinic system with space group <i>Cc</i>, which exhibits a typical spin-chain structure. In the structural framework, Co<sup>2+</sup> ions form a zigzag chain via edge-sharing oxygen atoms, and further the zigzag Co-chains are separated by linear [B<sub>2</sub>P<sub>2</sub>O<sub>8</sub>]<sub>∞</sub> chains. Magnetic measurements confirm that Co<sub>3</sub>(BPO<sub>4</sub>)<sub>2</sub>­(PO<sub>4</sub>)­(OH)<sub>3</sub> possesses an antiferromagnetic ordering at <i>T</i><sub>N</sub> = 12 K, while a 1/3 plateau is observed in the magnetization curve at 2 K. The possible spin arrangements for antiferromagnetic, ferrimagnetic, and ferromagnetic states are also suggested

    Analog Memristors Based on Thickening/Thinning of Ag Nanofilaments in Amorphous Manganite Thin Films

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    We developed an analog memristor based on the thickening/thinning of Ag nanofilaments in amorphous La<sub>1–<i>x</i></sub>Sr<sub><i>x</i></sub>MnO<sub>3</sub> (a-LSMO) thin films. The Ag/a-LSMO/Pt memristor exhibited excellent pinched hysteresis loops under high-excitation frequency, and the areas enclosed by the pinched hysteresis loops shrank with increasing excitation frequency, which is a characteristic typical of a memristor. The memristor also showed continuously tunable synapselike resistance and stable endurance. The a-LSMO thin films in the memristor acted as a solid electrolyte for Ag<sup>+</sup> cations, and only the Ag/a-LSMO/Pt memristor electroformed with a larger current compliance easily exhibited high-frequency pinched hysteresis loops. On the basis of the electrochemical metallization (ECM) theory and electrical transport models of quantum wires and nanowires, we concluded that the memristance is ultimately determined by the amount of charge supplied by the external current. The state equations of the memristor were established, and charge was the state variable. This study provides a new analog memristor based on metal nanofilaments thickening/thinning in ECM cells, which can be extended to other resistive switching materials. The new memristor may enable the development of beyond von Neumann computers

    Quantification of Arachidonic Acid and Its Metabolites in Rat Tissues by UHPLC-MS/MS: Application for the Identification of Potential Biomarkers of Benign Prostatic Hyperplasia

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    <div><p>To evaluate the potential relationship between benign prostatic hyperplasia (BPH) and the arachidonic acid (AA) metabolome, a UHPLC—MS/MS method has been developed and validated for simultaneous determination of AA and its cyclooxygenase(COX) and lipoxygenase(LOX) pathway metabolites (15-HETE, 12-HETE, TXA<sub>2</sub>, 5-HETE, AA, PGI<sub>2</sub>, PGF<sub>2α</sub>, 8-HETE, PGD<sub>2</sub>, PGE<sub>2</sub> and LTB<sub>4</sub>) in rat tissues. The analytes were extracted from tissue samples with a protein precipitation procedure and then separated on a Shim-pack XR-ODSC18 column with 0.05% formic acid in water (pH adjusted with dilute ammonia) and methanol:acetonitrile (20:80, v/v). Detection was performed on a UHPLC—MS/MS system with electrospray negative ionization (ESI) and a multiple reaction-monitoring mode. The lower limits of quantification (LLOQ) were 0.25–50 ng/mL for all of the analytes in the prostate, seminal, bladder, liver and kidney tissues. The absolute recoveries of the analytes from all of the tissues were more than 50%. By means of the method developed, the AA metabolites in tissue samples from Sham and BPH group rats were determined. The eleven biomarkers in the BPH group prostate, seminal, bladder, liver and kidney tissues were significantly higher than those of the sham group, indicating that BPH fortified the inducible expression of COX and LOX, as well as increased the production of AA and eicosanoids. The method described here offers a useful tool for the evaluation of complex regulatory eicosanoids responses in vivo.</p></div

    Levels of individual analytes measured in prostate, seminal, bladder, liver and kidney in saline and testosterone-induced rats.

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    <p>Levels of individual analytes measured in prostate, seminal, bladder, liver and kidney in saline and testosterone-induced rats.</p

    Representative chromatograms of AA and its metabolites in blank prostate sample (1), blank prostate sample spiked with the analytes (2), A to N at LLOQ and a prostate sample from a BPH rat (3).

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    <p>(A) 15-HETE, (B) 12-HETE, (C) TXA<sub>2</sub>, (D) 5-HETE, (E) AA, (F) PGI<sub>2</sub>, (G) PGF<sub>2α</sub>, (H) 8-HETE, (I) PGD<sub>2</sub>, (J) PGE<sub>2</sub>, (K) LTB<sub>4</sub>, (L) AA-d<sub>8</sub>, (M) PGE<sub>2</sub>-d<sub>4</sub> and (N) 15-HETE-d<sub>8</sub></p

    Hematoxylin and eosin staining of prostate ventral lobe (1) and dorsal lobe (2) from sham group rats (A) and BPH induced rats (B).

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    <p>Hematoxylin and eosin staining of prostate ventral lobe (1) and dorsal lobe (2) from sham group rats (A) and BPH induced rats (B).</p

    The histograms of 11 analytes in prostate, bladder, seminal, liver, kidney from BPH group rats (BPH) and sham group rats (sham).

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    <p>The histograms of 11 analytes in prostate, bladder, seminal, liver, kidney from BPH group rats (BPH) and sham group rats (sham).</p

    Eicosanoid profiles from each rat tissue were analyzed using PLS-DA to examine variation between samples represented by scores plot (R<sup>2</sup><i>x</i>[1] = 0.446, R<sup>2</sup><i>x</i>[2] = 0.183, Ellipse:Hotelling T<sub>2</sub>(95%)) of a two-component PLS-DA model of the dataset (A) and loadings plot of the same dataset (B).

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    <p>Eicosanoid profiles from each rat tissue were analyzed using PLS-DA to examine variation between samples represented by scores plot (R<sup>2</sup><i>x</i>[1] = 0.446, R<sup>2</sup><i>x</i>[2] = 0.183, Ellipse:Hotelling T<sub>2</sub>(95%)) of a two-component PLS-DA model of the dataset (A) and loadings plot of the same dataset (B).</p

    Stability of the eleven analytes in rat plasma under different storage conditions (n = 3).

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    <p>Stability of the eleven analytes in rat plasma under different storage conditions (n = 3).</p
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