Construction of nanostructures in aqueous solution from amphiphilic glucose‐derived polycarbonates

Carbohydrates are the fundamental building blocks of many natural polymers, their wide bioavailability, high chemical functionality, and stereochemical diversity make them attractive starting materials for the development of new synthetic polymers. In this work, one such carbohydrate, d ‐glucopyranoside, was utilized to produce a hydrophobic five‐membered cyclic carbonate monomer to afford sugar‐based amphiphilic copolymers and block copolymers via organocatalyzed ring‐opening polymerizations with 4‐methylbenzyl alcohol and methoxy poly(ethylene glycol) as initiator and macroinitiator, respectively. To modulate the amphiphilicities of these polymers acidic benzylidene cleavage reactions were performed to deprotect the sugar repeat units and present hydrophilic hydroxyl side chain groups. Assembly of the polymers under aqueous conditions revealed interesting morphological differences, based on the polymer molar mass and repeat unit composition. The initial polymers, prior to the removal of the benzylidenes, underwent a morphological change from micelles to vesicles as the sugar block length was increased, causing a decrease in the hydrophilic–hydrophobic ratio. Deprotection of the sugar block increased the hydrophilicity and gave micellar morphologies. This tunable polymeric platform holds promise for the production of advanced materials for implementation in a diverse range of applications. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 432–440     

Experimental Investigation on Turbulent Structure of Drag Reducing Channel Flow with Blowing Polymer Solution from the Wall

Turbulent drag reducing flow with blowing polymer solution from the channel wall was investigated experimentally using particle image velocimetry (PIV). Experiments were carried out with varying conditions of blowing polymer solution (e.g. weight concentration of polymer solution). Reynolds number based on the channel height and mean velocity was set to 20000 and 40000. When the polymer solution was blown from the channel wall, streamwise velocity fluctuation little increased, but wall-normal velocity fluctuation, Reynolds shear stress and correlation coefficient decreased significantly only near the blower wall. This behavior corresponds to the decrease of the ejection and sweep in the near-wall region observed by the investigation of instantaneous velocity map. On the contrary, this characteristic behavior was not observed at a position away from the blower wall (y/(H/2) > 0.4) and the scatter plot was almost the same as that of the water flow in this region. These results suggest that there are two regions in the drag reducing flow with blowing polymer solution from the wall; one is a non-Newtonian region which exists near the blower wall, and the other is a Newtonian region at a distance from the wall. The non-Newtonian region plays a key role in the drag reduction by the blowing polymer solution.     

Sensitive determination of 4-(4-chlorophenyl)-4-hydroxypiperidine, a metabolite of haloperidol, in a rat biological sample by HPLC with fluorescence detection after pre-column derivatization using 4-fluoro-7-nitro-2,1,3-benzoxadiazole

4-(4-Chlorophenyl)-4-hydroxypiperidine (CPHP), one of the metabolites of haloperidol, is considered to exhibit brain toxicity. CPHP concentrations in plasma and tissue homogenates (each 200 microL) from rats were analyzed by HPLC fluorescence detection after pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F). After basic extraction of the samples with benzene, the derivatization with NBD-F was conducted in borate buffer (pH 8.0) at 60 degrees C for 3 min. Mexiletine was carried through the procedure as an internal standard. The regression equation for CPHP showed a good linearity in the range of 0.03-1 microg/mL with a detection limit of 0.008 microg/mL. The coefficient of variation was less than 11.6%. Plasma concentration-time courses of CPHP after intraperitoneal or per oral administration of CPHP, haloperidol or reduced haloperidol were examined, and the pharmacokinetic parameters were estimated. Additionally, CPHP levels in various tissues at 8 h after intraperitoneal administration of these compounds were compared. The method was simple and sensitive, useful for determination of CPHP in rat biological samples using as little as 200 microL of sample volume and could be applied for pharmacokinetic study.     

Sodium‐ and Potassium‐Hydrate Melts Containing Asymmetric Imide Anions for High‐Voltage Aqueous Batteries

Aqueous Na‐ or K‐ion batteries could virtually eliminate the safety and cost concerns raised from Li‐ion batteries, but their widespread applications have generally suffered from narrow electrochemical potential window (ca. 1.23 V) of aqueous electrolytes that leads to low energy density. Herein, by exploring optimized eutectic systems of Na and K salts with asymmetric imide anions, we discovered, for the first time, room‐temperature hydrate melts for Na and K systems, which are the second and third alkali metal hydrate melts reported since the first discovery of Li hydrate melt by our group in 2016. The newly discovered Na‐ and K‐ hydrate melts could significantly extend the potential window up to 2.7 and 2.5 V (at Pt electrode), respectively, owing to the merit that almost all water molecules participate in the Na⁺ or K⁺ hydration shells. As a proof‐of‐concept, a prototype Na₃V₂(PO₄)₂F₃|NaTi₂(PO₄)₃ aqueous Na‐ion full‐cell with the Na‐hydrate‐melt electrolyte delivers an average discharge voltage of 1.75 V, that is among the highest value ever reported for all aqueous Na‐ion batteries.     

Effect of Home-based Exercise Therapy for Peripheral Arterial Disease Patients Underwent Endovascular Treatment: A Clinical Controlled Design

Objective: This study aimed to clarify the effect of home-based exercise therapy on physical activity in peripheral arterial disease (PAD) patients after EVT. Methods: Study design was controlled clinical design. The subjects were 30 patients (76.6% men) who underwent EVT in the Sakakibara Heart Institute of Okayama. Patients with EVT meeting the inclusion criteria were divided into two groups, intervention group (Home-based exercise) and control group. Patients'' basic characteristics, the number of steps walked and QOL questionnaire (WIQ, SEPA, Vascu QOL) were assessed before surgery and, at the 3 month after discharge. A two-way analysis of variance (ANOVA) was performed to compare number of steps walked and QOL questionnaire. Results: Interaction effect were observed in the number of steps walked (F (1,28) =13.89, p<0.01). A multiple comparison test confirmed a significant increase between results of before surgery and at three months after surgery in the intervention group (p<0.01). An interaction between the presence and absence of intervention was found for the WIQ pain score (F(1,28) = 5.86, p=0.01), speed score (F(1,28) = 3.80, p=0.04) and SEPA (F(1,28) = 4.99, p=0.03). In a multiple comparison study, there was a significant increase in WIQ pain and speed scores in both groups before and 3 months after discharge from the hospital. Conclusion: Home-based exercise therapy using physical activity indices has the potential to improve number of steps and quality of life in patients with PAD after EVT.     

Pregeometric origin of the big bang

The temperature-dependent effective action for gravity is calculated in pregeometry. It indicates that the effective potential for the space-time metric has the minimum at the origin for extremely high temperature. The origin of the big bang can be taken as a local and spontaneous phase transition of the space-time from the pregeometric phase to the geometric one.     

Changes on distribution of absorbed dose rates in air in an urban area after the Fukushima Daiichi Nuclear Power Plant accident

Journal of Radioanalytical and Nuclear Chemistry - Tokatsu area was on one pathway of the radioactive plumes released in the Fukushima Daiichi Nuclear Power Plant accident and absorbed dose rate in...     

An Unusual Terpene Cyclization Mechanism Involving a Carbon–Carbon Bond Rearrangement

Terpene cyclization reactions are fascinating owing to the precise control of connectivity and stereochemistry during the catalytic process. Cyclooctat‐9‐en‐7‐ol synthase (CotB2) synthesizes an unusual 5‐8‐5 fused‐ring structure with six chiral centers from the universal diterpene precursor, the achiral C₂₀ geranylgeranyl diphosphate substrate. An unusual new mechanism for the exquisite CotB2‐catalyzed cyclization that involves a carbon–carbon backbone rearrangement and three long‐range hydride shifts is proposed, based on a powerful combination of in vivo studies using uniformly ¹³C‐labeled glucose and in vitro reactions of regiospecifically deuterium‐substituted geranylgeranyl diphosphate substrates. This study shows that CotB2 elegantly demonstrates the synthetic virtuosity and stereochemical control that evolution has conferred on terpene synthases.