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Considering the lack of detailed research on the antibacterial mechanism of polyoxometalates, we examined the synergistic effect of novel bulky mixed Ti/W hetero-polyoxometalates (K9.5H2.5 ï¼»α-Ge2Ti4W20O78］・ 29H2O; αTi4, K9H5 ï¼»α-Ge2Ti6W18O77］・16H2O; αTi6, K23H5ï¼»α-Ge4Ti12W36O154］・39H2O; αTi12, K9H5 ï¼»ß-Ge2Ti6W18O77］・ 45H2O; ßTi6) with the antibiotic oxacillin against vancomycin intermediate-resistant Staphylococcus aureus (VISA) using fractional inhibitory concentration (FIC) index and growth curve in this study. All polyoxometalates used in this study showed remarkable synergistic effects with oxacillin. Its synergistic antibacterial mechanism was examined using reverse transcription PCR (RT-PCR) and penicillin binding protein-2' (PBP2') latex agglutination test. The results suggested that these polyoxometalates did not inhibit mecA gene transcription but resulted in PBP2' protein malfunction. From these results, we concluded that the substances producing resistance in VISA were affected by polyoxometalates depending on their molecular size, facilitating a synergistic antibacterial effect with oxacillin.

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Phase separation is ubiquitous in nature and technology. So far, the focus has primarily been on phase separation occurring in the bulk phase. Recently, phase separation taking place in interfacial areas has attracted more attention - in particular, a combination of interfacial phase separation and hydrodynamics. Studies on this combination have been conducted intensively in this past decade; however, the detailed dynamics remain unclear. Here, we perform fluid displacement experiments, where a less viscous solution displaces a more viscous one in a radially confined geometry and phase separation occurs at the interfacial region. We demonstrate that a finger-like pattern, due to the viscosity contrast during the displacement, can be suppressed by the phase separation. We also claim that the direction of a body force, the so-called Korteweg force, which appears during the phase separation and induces convection, determines whether the fingering pattern is suppressed or changed to a droplet pattern. The change of the fingering pattern to the droplet pattern is enhanced by the Korteweg force directed from the less viscous solution to the more viscous one, whereas the fingering is suppressed by the force directed in the opposite direction. These findings will contribute directly to the higher efficiency of processes such as enhanced oil recovery and CO2 sequestration, where interfacial phase separation is considered to occur during the flow.

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The effects of countercations and coexisting compounds on the molecular structure of the [M(α-PW11O39)2] n- polyanion were analyzed in terms of the repulsion and twisting of two [α-PW11O39]7- units. More specifically, it was found that two [α-PW11O39]7- ions approached one another upon reducing the ionic radius of M in [M(α-PW11O39)2] n-. The interactive twisting of the [α-PW11O39]7- units prevented mutual repulsion of the units containing terminal O atoms, and the tendency for approach and twisting of the [α-PW11O39]7- units varied as a function of the type of countercation and the presence of coexisting compounds. Overall, this study demonstrated that some interactions between the counteraction and coexisting compounds with [M(α-PW11O39)2] n- determined the molecular conformation and the isolated form of the polyanion.

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A chemical reaction in the flow field affects the physical property of fluids, resulting in changing flow dynamics. The effect of the reaction on the flow dynamics is normally evaluated by comparison between the physical properties of the fluid between pre- and post-reaction. However, our group found a polymeric reacting flow in which a comparison between pre- and post-reaction fluid properties is insufficient to evaluate the influences of the reaction on the flow dynamics (T. Ueki et al., J. Phys. Chem. B, 2019, 123, 4587-4593). In the study, we examined the stirred flow by an impeller in a beaker with a chemical reaction between partially hydrolyzed polyacrylamide (HPAM) solution and Fe(NO3)3 solution. We found that a so-called Weissenberg effect, where the stirred solution climbs up the stirring shaft because of an increase in the viscoelasticity of the mixed solution, transiently appeared in only the halfway of the reaction, although the reaction slightly decreased the solution's viscosity at the final stage under a certain pH and we proposed the mechanism for the temporal increase in the viscoelasticity. In the present study, we conducted similar experiments as our previous study using HPAM solution at various pH and two concentrations of Al(NO3)3 solutions. The unpredictable flow dynamics by comparison between pre- and post-reaction fluid properties, i.e., the appearance and disappearance of the Weissenberg effect, has been observed under a certain pH and Al(NO3)3 concentration. We investigated the mechanism by means of the simultaneous measurement of pH and the stirring torque and the identification of the dominant species of aluminum aqua complexes by the Henderson-Hasselbalch equation. As a result, we proposed two mechanisms of dissapearance of the Weissenberg effect: one is the same for the Fe(NO3)3 case but the other is unique and novel for the Al(NO3)3 case. This study can contribute to the comprehensive understanding of the conditions for the occurrence of the unpredictable dynamics of polymeric reacting flow by comparison between the pre- and post-reaction fluid properties.

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Objectives This study aimed to examine whether a new imaging method (80-kV forward-projected model-based iterative reconstruction solution [FIRST] protocol) that uses a combination of low tube voltage and FIRST can reduce radiation dose and contrast medium volume by comparing the quality of the resulting image with that of the image obtained by 120-kV adaptive iterative dose reduction 3D protocol in the equilibrium phase of chest-pelvic computed tomography (CT). Subjects and methods Twenty-seven patients underwent CT by both protocols on different days. Two radiologists subjectively assessed image quality by scoring axial images for sharpness, contrast enhancement, noise, artifacts, and overall quality. The mean CT values, standard deviations, contrast-to-noise ratios, and signal-to-noise ratios in the liver, aorta, and erector spinae muscles were used for objective assessment. Radiation dose parameters included the CT dose index volume, dose-length product, effective dose, and size-specific dose estimate. Results were compared for different body mass index categories. Results The 80-kV FIRST protocol helped achieve mean reductions of 36.3%, 35.7%, and 36.6% in CT dose index volume, effective dose, and size-specific dose estimate, respectively (p < 0.01). Therefore, this protocol was regarded as comparable to the conventional protocol in image quality, except for visual sharpness. Conclusions The 80-kV FIRST protocol is capable of reducing radiation dose and contrast medium volume compared to the adaptive iterative dose reduction 3D protocol in the equilibrium phase of chest-pelvic CT.

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In reacting flows, changes in fluid properties induced by the chemical reaction can alter the flow dynamics. Generally, these changes in fluid properties are evaluated by comparison between their pre- and post-reaction properties. If a fluid property such as viscosity decreases between pre- and post-reaction, we expect a decrease in viscosity to occur in the reacting flow. However, this study demonstrates a reacting polymeric liquid flow where a remarkable increase in the viscoelasticity temporally occurs despite the viscosity slightly decreasing after the reaction. We elucidated the underlying reaction mechanism, which involves a structural change in the side functional group (carboxyl) in polyacrylamide at ultrahigh molecular weights ( Mw > 106) with ultralow concentrations ([polymer] < 1 wt %) by using ATR-FTIR spectroscopy. This study demonstrates the existence of a reacting flow in which examination of microscopic molecular structure is required to understand the macroscopic flow dynamics. The findings will be valuable not only for industrial application such as reactor designs and rheology control but also for opening a new research area: chemically reacting flow involving the diagnosis of molecule structure.

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Chiral crystalline compounds of the series of [Ln(α2-P2W17O61)2]17- polyanions embracing nearly all the lanthanide (Ln) ions were successfully isolated using Pro (proline) as a chiral director. In each compound, the polyanion and Pro were associated through a stereoselective interaction involving N(H)···O hydrogen bonding. 31P NMR and circular dichroism studies revealed the induction of chirality by Pro in the racemic aqueous systems of the [Ln(α2-P2W17O61)2]17- polyanions, i.e., the Pfeiffer effect. Mechanistically, this racemization was regulated by competitive enantiomeric interactions between the l-/d-Pro and l-/d-polyanions, with only one racemization route (the on-site rotation of the [α2-P2W17O61)]10- unit) observed, independent of the nature of Ln.

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The Co(2+) ion in the title compound, Rb[Co(C3H7NO3)(H2O)5][H6CoMo6O24]·C3H7NO3·10H2O, is coordinated by five water mol-ecules and one O-monodentate l-serine ligand in a slightly distorted octahedral geometry. The Rb(+) ion is irregularly coordinated by nine O atoms. In the crystal, the [H6Co(III)Mo6O24](3-) polyanions are stacked along the b-axis direction, mediated by bridging Rb-O bonds. N-H⋯O and O-H⋯O hydrogen bonds are observed involving the l-serine mol-ecules.

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Enantiopure crystals of K(1.3)Na(3.2)H(6.5)[l-Pr(PW(11)O(39))(2)]·8.3l-proline·21.5H(2)O (1), K(1.3)Na(3.2)H(6.5)[d-Pr(PW(11)O(39))(2)]·8.3d-proline·17H(2)O (2), and K(1.3)Na(3.2)H(6.5)[l-Er(PW(11)O(39))(2)]·8.3l-proline·22.5H(2)O (3) were successfully obtained by using l- and d-proline (pro) as chiral auxiliary agents. In these crystals, l- and d-[Ln(PW(11)O(39))(2)](11-) anions are attached by two l- and d-pro molecules, respectively, through a O···N hydrogen-bonding interaction between the square-antiprismatic LnO(8) center and amino-N atoms. The l- and d-[Pr(PW(11)O(39))(2)](11-) anions in aqueous solutions exhibited a couple of mirror-imaged CD spectra due to (3)H(4/2)→(3)P(0,1,2) and (1)D(2) transitions in the stereogenic Pr(3+) center. Chirality inductions by l- and d-pro from a racemic solution of [Er(PW(11)O(39))(2)](11-) was demonstrated by means of CD spectroscopy.

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