Influence of xyloglucan on gelatinization and retrogradation of tapioca starch

Dynamic and steady shear rheometry and differential scanning calorimetry (DSC) were used to investigate effects of xyloglucan (XG) on gelatinization and retrogradation of tapioca starch (TS). The viscosity of TS/XG pastes immediately after gelatinization increased with increasing XG content at the total polysaccharide concentration of 3.5%. Gelatinized TS alone showed pseudoplastic flow at low shear rates and dilatant behavior at higher shear rates (about >1 s⁻¹), while mixtures with XG did not show dilatancy. Mechanical spectra of TS pastes containing XG were more liquid-like than those of TS pastes without XG. XG provides shear stability to the TS during storage. Increases in dynamic moduli during storage at 5 °C were suppressed in the presence of XG. In contrast, the retrogradation ratio determined based on DSC increased more rapidly in the presence of XG. These results suggest that XG forms a continuous liquid phase in a mixture to impart better mechanical stability during storage but to accelerate re-ordering of starch polysaccharides by effectively reducing the amount of water available for starch.     

Viscoelastic properties of concentrated aqueous ethanol suspensions of α-zein

Viscoelastic properties of α-zein dispersed in aqueous ethanol were studied using oscillatory strain rheometry. In 55-80% v/v aqueous ethanol, zein was only partially soluble, forming a gel at a sufficiently high zein concentration. The strain dependence of the storage modulus and the loss modulus of gelled systems exhibited features characteristic to closely-packed swollen particles. Close-packing was found to occur at a lower zein concentration with increasing ethanol concentration as the threshold for gelation decreased from a zein concentration of ca. 29 to 20% w/v with increasing ethanol concentration from 55 to 80% v/v. A contrasting trend in the effect of the solvent quality was revealed at a constant zein concentration of 30% w/v, at which the storage modulus decreased from ca. 12,000-700 Pa with increasing ethanol concentration from 55 to 80% v/v. The two major factors determining viscoelastic properties of the partially solvated zein systems were identified to be: (1) the degree of dissolution of zein into the continuous phase that was negatively correlated with the volume fraction of the dispersed phase and positively correlated with the osmotic pressure of the continuous phase; and (2) the degree of swelling of partially solvated zein particles that was positively and negatively correlated with the volume fraction and the storage modulus of the dispersed phase, respectively.     

Enzymatic properties and transglycosylation of α-galactosidase from Penicillium oxalicum SO

Penicillium oxalicum SO α-galactosidase demonstrated weak hydrolysing activity but a high rate of transglycosylation in the reaction with melibiose, where the major product was 6-α-galactosyl melibiose. The transfer ratio was 83.6% and was maintained over a long reaction time of 80 h. The molecular weight was estimated to be 124,000 by SDS–PAGE. The optimal pH was ∼3 and a stable pH, with a range of 2.4–9.5, was found. The optimal temperature was ∼60 °C and the activity was stable below 60 °C. With respect to acceptor specificity, mono-alcohols, sugar alcohols and sugars were poor acceptors, but the di-alcohol ethylene glycol and the tri-alcohol glycerin were good acceptors. The percentage of transglycosylation to glycerin increased up to 41.7%, as that to melibiose decreased, with the initial glycerin concentration of 40%. The production of α-d-galactosylglycerol was 293 mg for each gram of melibiose used by the enzymatic reaction.     

Validation of MAAP model enhancement for Fukushima Dai-ichi accident analysis with Phenomena Identification and Ranking Table (PIRT)

The Modular Accident Analysis Program (MAAP) model enhancement items to improve the simulation capability for molten corium behavior in the accidents at the Fukushima Dai-ichi nuclear power plants were validated with the Phenomena Identification and Ranking Table (PIRT). The importance ranks of the identified phenomena were evaluated for each time phase through brainstorming and discussion with the experts in the Atomic Energy Society of Japan and the members of the MAAP model enhancement project. When the current MAAP evaluation models were reviewed with the PIRT, it is found that 95 of the 386 high-ranked phenomena were not considered in MAAP 5.0.1. While 62 of these phenomena will have been addressed in the MAAP enhancement project and 25 others are not suitable to be analyzed by MAAP, 8 important phenomena should be considered in post-MAAP enhancement project with additional experiments or fundamental studies.     

Advanced fabrication technologies of integrated-type structure for a-Si solar cells

This paper proposes a new advanced fabrication technology for a low-cost integrated-type a-Si solar cell. Integrated-type cells provide many advantages and have been industrialized with a laser patterning method. However, a higher throughput and more efficient patterning method was required for applying a-Si solar cells to a power generating system. Plasma CVM (Chemical Vaporization Machining) was first applied to advanced patterning because of its advantages of high speed and selectivity. In this method, a plasma generated under high pressure localizes near the wire electrode and concentrates reactive radicals. As a result, we achieved an etching rate of more than 1 μm/s and selective patterning of a 200 μm-wide a-Si layer in 1 s multiline patterning was also developed for large-area modules.     

The role of energy intensity improvement in the AR4 GHG stabilization scenarios

This study analyzes the role of energy intensity improvement in the short term (to the year 2020) and midterm (to the year 2050) in the context of long-term greenhouse gases (GHG) stabilization scenarios. The data come from the latest Emissions Scenarios Database and were reviewed in the Fourth Assessment Report (AR4) by the Intergovernmental Panel on Climate Change. In this study, quantitative decomposition analyses using the extended Kaya identity are applied to the stabilization scenarios in Categories I to IV of Table SPM.5 in the AR4. Furthermore, quantitative decomposition analyses of Category IV scenarios are conducted for major GHG-emitting countries, such as the USA, Western Europe, China, and India, by utilizing the large number of reports in the database. This study provides in-depth analyses of the relationship between energy intensity improvement and other major indicators. One finding is that energy intensity improvement plays an important role in the short term, and the rate of energy intensity improvement is assumed to be around 2% per year as a median value across Categories I–III in the midterm on the global scale. However, achieving stringent stabilization levels requires various other measures regarding the use of less-carbon intensive fossil fuels, the shift to non-fossil fuel energies, and advanced technologies such as carbon capture and storage.

Studies on bulk diffusion and local diffusion of polystyrene in melt

Results of bulk viscosity (η) and local viscosity (ξ) of various molecular weights of polystyrene (PS) have been reported. In this paper the relationship between η and bulk diffusion coefficient (D_B), and that between ξ and local diffusion coeffizient (D_L) are presented. Data obtained lead to several conclusions. From the results of unperturbed dimensions and a universal constant (Φ), it was found that F. Bueche's equation D_B · η = const. is valid for polystyrenes with molecular weights over 600. Temperature and component concentration dependence of bulk diffusion coefficient for the two-component blend system may be interpreted in terms of the free volume theory. At an iso-free volume state, molecular weight dependences of bulk diffusion coefficients for both PS of narrow distribution of molecular weight and blend PS can be composed to a single curve, which is composed of two straight lines in a double logarithmic presentation with intersection at M_w = 1.78 × 10⁴ g/mol. The slopes of these two lines were ? 1.0 and ? 3.3, respectively. The product D_L · ξ was determined to be 1.10 × 10^?7 (c.g.s) for n-paraffines from the data of self-diffusion coefficient and ξ. This made it possible to determine D_L from ξ. For higher molecular weights of PS, log D_B is a linear function of log M_w while log D_L stays almost constant.     

Photo-induced valence tautomerism in Co complexes

A number of photofunctional molecular compounds have been developed recently. Typical examples of these are phototunable valence tautomeric compounds, which are now attracting great attention. When the charge-transfer bands of some Co valence tautomeric compounds are excited at low temperature, metastable redox isomers can be created after irradiation. The lifetimes of the metastable states can be more than several hours. These transformations can involve changes in the magnetic properties of the compounds, as well as their color. Hence, these compounds can be regarded as novel photomagnetic materials. The photoresponsive behaviors of these valence tautomeric compounds are similar to those of spin-crossover complexes (light-induced excited spin-state trapping effects).     

A Novel In Vitro Assay Using Human iPSC-Derived Sensory Neurons to Evaluate the Effects of External Chemicals on Neuronal Morphology: Possible Implications in the Prediction of Abnormal Skin Sensation

Neuronal morphological changes in the epidermis are considered to be one of causes of abnormal skin sensations in dry skin-based skin diseases. The present study aimed to develop an in vitro model optimised for human skin to test the external factors that lead to its exacerbation. Human-induced pluripotent stem cell-derived sensory neurons (hiPSC-SNs) were used as a model of human sensory neurons. The effects of chemical substances on these neurons were evaluated by observing the elongation of nerve fibers, incidence of blebs (bead-like swellings), and the expression of nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2). The nerve fiber length increased upon exposure to two common cosmetic preservatives—methylparaben and phenoxyethanol—but not to benzo[a]pyrene, an air pollutant at the estimated concentrations in the epidermis. Furthermore, the incidence of blebs increased upon exposure to benzo[a]pyrene. However, there was a decrease in the expression of NMNAT2 in nerve fibers, suggesting degenerative changes. No such degeneration was found after methylparaben or phenoxyethanol at the estimated concentrations in the epidermis. These findings suggest that methylparaben and phenoxyethanol promote nerve elongation in hiPSC-SNs, whereas benzo[a]pyrene induces nerve degeneration. Such alterations may be at least partly involved in the onset and progression of sensitive skin.