1H NMR,thermal, and conductivity studies on PVAc based gel polymer electrolytes

The lithium‐ion conducting gel polymer electrolytes (GPE), PVAc‐DMF‐LiClO₄ of various compositions have been prepared by solution casting technique. ¹H NMR results reveal the existence of DMF in the gel polymer electrolytes at ambient temperature. Structure and surface morphology characterization have been studied by X‐ray diffraction analysis (XRD) and scanning electron microscopy (SEM) measurements. Thermal and conductivity behavior of polymer‐ and plasticizer‐salt complexes have been studied by differential scanning calorimetry (DSC), TG/DTA, and impedance spectroscopy results. XRD and SEM analyses indicate the amorphous nature of the gel polymer‐salt complex. DSC measurements show a decrease in T_g with the increase in DMF concentrations. The thermal stability of the PVAc : DMF : LiClO₄ gel polymer electrolytes has been found to be in the range of (30–60°C). The dc conductivity of gel polymer electrolytes, obtained from impedance spectra, has been found to vary between 7.6 × 10^?7 and 4.1 × 10^?4 S cm^?1 at 303 K depending on the concentration of DMF (10–20 wt %) in the polymer electrolytes. The temperature dependence of conductivity of the polymer electrolyte complexes appears to obey the VTF behavior. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Possible Alterations in ��-Synuclein, the Non-Amyloidogenic Homologue of ��-Synuclein, during Progression of Sporadic ��-Synucleinopathies

α-Synucleinopathies are neurodegenerative disorders that are characterized by progressive decline of motor and non-motor dysfunctions. α-Synuclein (αS) has been shown to play a causative role in neurodegeneration, but the pathogenic mechanisms are still unclear. Thus, there are no radical therapies that can halt or reverse the disease’s progression. β-Synuclein (βS), the non-amyloidogenic homologue of αS, ameliorates the neurodegeneration phenotype of αS in transgenic (tg) mouse models, as well as in cell free and cell culture systems, which suggests that βS might be a negative regulator of neurodegeneration caused by αS, and that “loss of function” of βS might be involved in progression of α-synucleinopathies. Alternatively, it is possible that “toxic gain of function” of wild type βS occurs during the pathogenesis of sporadic α-synucleinopathies, since tg mice expressing dementia with Lewy bodies-linked P123H βS develop progressive neurodegeneration phenotypes, such as axonal pathology and dementia. In this short review, we emphasize the aspects of “toxic gain of function” of wild type βS during the pathogenesis of sporadic α-synucleinopathies.     

Monitoring of acrylamide concentrations in potato chips in Japan between 2006 and 2010

Acrylamide levels in commercially available potato chips in Japan were monitored between August 2006 and June 2010 using the xanthydrol derivative gas chromatography-mass spectrometry (GC-MS) method. Seasonal and annual changes in acrylamide concentrations were determined. Nationwide bimonthly sampling of potato chips was carried out using a four-level design, and seasonal variations were detected in which the minimum acrylamide concentration was observed in August, and the maximum between February and June. Seasonal variations became less apparent after August 2008 as a result of annual effects and/or mitigation measures taken by the potato chip producers. Sampling uncertainties were separated into time-to-time, city-to-city, and lot-to-lot variation, and the largest variation was shown to be lot-to-lot including bag-to-bag.     

Gas detection by structural variations of fluorescent guest molecules in a flexible porous coordination polymer

The development of a new methodology for visualizing and detecting gases is imperative for various applications. Here, we report a novel strategy in which gas molecules are detected by signals from a reporter guest that can read out a host structural transformation. A composite between a flexible porous coordination polymer and fluorescent reporter distyrylbenzene (DSB) selectively adsorbed CO? over other atmospheric gases. This adsorption induced a host transformation, which was accompanied by conformational variations of the included DSB. This read-out process resulted in a critical change in DSB fluorescence at a specific threshold pressure. The composite shows different fluorescence responses to CO? and acetylene, compounds that have similar physicochemical properties. Our system showed, for the first time, that fluorescent molecules can detect gases without any chemical interaction or energy transfer. The host-guest coupled transformations play a pivotal role in converting the gas adsorption events into detectable output signals.     

Formation of Ultrafine‐Grained Microstructure of Ti–6Al–4V Alloy by Hot Deformation of α′ Martensite Starting Microstructure

We have presented a formation of ultrafine‐grained microstructure (d_α ≈ 0.2 µm) of industrial Ti–6Al–4V alloy produced by the hot compression of a sample with the acicular α′ martensite starting microstructure. The hot‐deformation behavior was different from the case of the conventional (α + β) starting microstructure, that is, the phase transformation of α′/(α + β) during hot working enhanced the microstructural conversion, especially under the conditions of a low temperature and a high‐strain rate.     

Temperature dependence and fracture criterion of mixed mode I/II fracture toughness of phenolic resin for friction material

In this study, the temperature dependence of the mixed‐mode fracture toughness of the phenolic resin for friction materials is investigated. For pure mode I, the fracture toughness decreases as the temperature increases, and it increases again after showing its minimum value. For pure mode II, the fracture toughness shows a similar trend but has its minimum value at a higher temperature. The temperature dependence of the mixed‐mode fracture toughness varies depending on the mode mixity, which is attributed to the different sensitivity to the relaxation phenomenon. At room temperature, as the fracture toughness for pure mode I and II are almost the same, the fracture locus shows a circular arc. At elevated temperatures, the locus becomes smaller and noncircular. At high temperature, the fracture locus shows an elliptical arc, where the fracture toughness for pure mode II is smaller than that for mode I. An empirical fracture criterion based on the time‐temperature dependence of the resin is proposed, and the proposed method successfully predicts the fracture toughness under various conditions of the temperature, time, and mode mixity. The crack initiation angles, on the other hand, are almost consistent regardless of the temperature, which agree with the maximum hoop stress theory. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Simultaneous Estimation of the Thermophysical Properties of Selected Liquid Dairy Products by a Transient Heat Flow Probe Method

The thermophysical properties of reconstituted whole milk, skim milk, and whey were measured at various temperatures and concentrations. A new method for the simultaneous determination of thermophysical properties using a modified version of current probe theory method was proposed. Two new correction coefficients were introduced, and using the values of these coefficients and an approximate solution of the heat conduction equation, the thermal conductivity and thermal diffusivity of each sample were determined. The specific heat of each sample was estimated from the definition of thermal diffusivity. These properties were expressed as a function of concentration and temperature.     

Differences between Human and Mouse IgM Fc Receptor (FcµR)

Both non-immune “natural” and antigen-induced “immune” IgM are important for protection against pathogens and for regulation of immune responses to self-antigens. Since the bona fide IgM Fc receptor (FcµR) was identified in humans by a functional cloning strategy in 2009, the roles of FcµR in these IgM effector functions have begun to be explored. In this short essay, we describe the differences between human and mouse FcµRs in terms of their identification processes, cellular distributions and ligand binding activities with emphasis on our recent findings from the mutational analysis of human FcµR. We have identified at least three sites of human FcµR, i.e., Asn66 in the CDR2, Lys79 to Arg83 in the DE loop and Asn109 in the CDR3, responsible for its constitutive IgM-ligand binding. Results of computational structural modeling analysis are consistent with these mutational data and a model of the ligand binding, Ig-like domain of human FcµR is proposed. Serendipitously, substitution of Glu41 and Met42 in the CDR1 of human FcµR with mouse equivalents Gln and Leu, either single or more prominently in combination, enhances both the receptor expression and IgM binding. These findings would help in the future development of preventive and therapeutic interventions targeting FcµR.     

The impact of air contaminants on PEMFC performance and durability

The impact of air contaminants such as sulfur compounds (SO₂, H₂S) and nitrogen compounds (NO_x and NH₃) was investigated using subscale fuel cells. The severity of the effect of these impurities varies depending on the contaminants. Among air contaminants, sulfur compounds cause the most severe performance loss due to decrease of available Pt sites for oxygen reduction reaction (ORR). We found that sulfur compounds adsorbed on Pt surface tend to be oxidized to sulfate at 0.9 V and higher potentials. The cell performance can be recovered partially by excursions to high potentials due to increase of available Pt sites. Furthermore, flushing the cathode with high humidity gases results in almost complete recovery of the cell performance. We conclude that these recovery effects are due to oxidation/removal of the contaminants from the Pt surface.     

CeO2–ZrO2 Solid Solution Catalyst for Selective Synthesis of Dimethyl Carbonate from Methanol and Carbon Dioxide

CeO₂–ZrO₂ solid solution catalysts are very effective for the selective synthesis of dimethyl carbonate from methanol and CO₂. The activity was much dependent on the calcination temperature. The higher the calcination temperature, the higher the activity of the catalyst for DMC formation, though the BET surface area is lower on the catalyst calcined at higher temperature.