Development of Ultrafine Multichannel Microfluidic Mixer for Synthesis of Bimetallic Nanoclusters: Catalytic Application of Highly Monodisperse AuPd Nanoclusters Stabilized by Poly(<i>N</i>‑vinylpyrrolidone)

On account of their novel properties, bimetallic nanoparticles and nanoclusters (NCs) are strong potential candidates for optical, magnetic, and catalytic functional materials. These properties depend on the chemical composition and size (number of constituent atoms) of the NCs. Control of size, structure, and composition is particularly important for fabricating highly functional materials based on bimetallic NCs. Size- and structure-controlled synthesis of two-element alloys can reveal their intrinsic electronic synergistic effects. However, because synergistic enhancement of activity is strongly affected by composition as well as by size and structure, controlled synthesis is a challenging task, particularly in catalytic applications. To investigate catalytic synergistic effects, we have synthesized highly monodisperse, sub-2 nm, solid-solution AuPd NCs stabilized with poly­(<i>N</i>-vinylpyrrolidone) (AuPd:PVP) using a newly developed ultrafine microfluidic mixing device with 15 μm wide multiple lamination channels. The synergistic enhancement for catalytic aerobic oxidation of benzyl alcohol exhibited a volcano-shaped trend, with a maximum at 20–65 at. % Pd. From X-ray photoelectron spectroscopic measurements, we confirmed that the enhanced activity originates from the enhanced electron density at the Au sites, donated by Pd sites

Coumarin–Spiropyran Dyad with a Hydrogenated Pyran Moiety for Rapid, Selective, and Sensitive Fluorometric Detection of Cyanide Anion

We synthesized a coumarin–spiropyran dyad with a hydrogenated pyran moiety (<b>2</b>), behaving as an off–on type fluorescent receptor for rapid, selective, and sensitive detection of cyanide anion (CN^–) in aqueous media. The receptor itself shows almost no fluorescence with a quantum yield < 0.01, due to the delocalization of π-electrons over the molecule. Selective nucleophilic addition of CN^– to the spirocarbon of the molecule rapidly promotes spirocycle opening within only 3 min. This leads to localization of π-electrons on the coumarin moiety and exhibits strong light-blue fluorescence at 459 nm with very high quantum yield (0.52). As a result of this, the receptor facilitates rapid, selective, and sensitive fluorometric detection of CN^– as low as 1.0 μM

Synthesis of Au Nanoparticles with Benzoic Acid as Reductant and Surface Stabilizer Promoted Solely by UV Light

Photoreductive synthesis of colloidal gold nanoparticles (AuNPs) from Au³⁺ is one important process for nanoprocessing. Several methods have been proposed; however, there is no report of a method capable of producing AuNPs with inexpensive reagents acting as both reductant and surface stabilizer, promoted solely under photoirradiation. We found that UV irradiation of water with Au³⁺ and benzoic acid successfully produces monodispersed AuNPs, where thermal reduction does not occur in the dark condition even at elevated temperatures. Photoexcitation of a benzoate–Au³⁺ complex reduces Au³⁺ while oxidizing benzoic acid. The benzoic acid molecules are adsorbed on the AuNPs and act as surface stabilizers. Change in light intensity and benzoic acid amount successfully creates AuNPs with controllable sizes. The obtained AuNPs can easily be redispersed in an organic solvent or loaded onto a solid support by simple treatments

Clinical features of subjects in Idiopathic recurrent acute pancreatitis (IRAP) subgroup with and without meandering main pancreatic duct (MMPD).

a<p>,Significant after family-wise correction;</p>b<p>,Student's t-test;</p>c<p>,Fisher's exact test; P₁, P-value for the test between IRAP subjects with and without MMPD; P₂, P-value for intergroup test between Community group (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037652#pone-0037652-t002" target="_blank">Table 2</a>) and IRAP subgroup; SD, standard deviation.</p

Rate of severe pancreatitis in patients with idiopathic acute and recurrent acute pancreatitis.

<p>CECT, contrast enhanced computed tomography; JPN, Japan; MMPD, meandering main pancreatic duct; NECT, non-enhanced computed tomography.</p

Schematic images of meandering main pancreatic duct (MMPD).

<p>The thick line indicates the common bile duct, and the thin line indicates the main pancreatic duct. MMPD was classified into subtypes based on its morphology in the head of pancreas on magnetic resonance cholangiopancreatography: normal type (A), examples of loop type (B1–2), and examples of reverse-Z type (C1–3). Assuming the body-axis as x-axis and horizontal direction as y-axis, MPD curves in loop and reverse-Z types have two extrema in horizontal direction respectively (arrows), while normal type has none. Dorsal pancreatic duct could be observed or not.</p

Clinical features of subjects in Community group with and without meandering main pancreatic duct (MMPD).

a<p>,Significant after family-wise correction;</p>b<p>,Student's t-test;</p>c<p>,Fisher's exact test; P, P-value for the test between Community group subjects with and without MMPD; SD, standard deviation.</p

Involved regions in idiopathic acute and recurrent acute pancreatitis.

<p>MMPD, meandering main pancreatic duct.</p

Clinical features of subjects in Idiopathic pancreatitis group with and without meandering main pancreatic duct (MMPD).

a<p>,Significant after family-wise correction;</p>b<p>,Student's t-test;</p>c<p>,Fisher's exact test; P₁, P-value for the test between idiopathic pancreatitis patients with and without MMPD; P₂, P-value for intergroup test between Community group (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037652#pone-0037652-t002" target="_blank">Table 2</a>) and Idiopathic pancreatitis group; SD, standard deviation.</p

Frequency of meandering main pancreatic duct (MMPD) and its contribution to idiopathic pancreatitis arranged by anatomical subtypes of MMPD and onset types of idiopathic pancreatitis.

a<p>, significant;</p>b<p>,numbers in square brackets represent percentages;</p>c<p>,Fisher's exact test;</p>d<p>,numbers in square brackets represent the 95% confidence interval; OR, odds ratio.</p