Overexpression of vacuolar H+‐ATPase‐related genes in bottom‐fermenting yeast enhances ethanol tolerance and fermentation rates during high‐gravity fermentation

Vacuolar H⁺‐ATPase (V‐ATPase) is thought to play a role in stress tolerance. In this study it was found that bottom‐fermenting yeast strains, in which the V‐ATPase‐related genes DBF2, VMA41/CYS4/NHS5 and RAV2 were overexpressed, exhibited stronger ethanol tolerance than the parent strain and showed increased fermentation rates in a high‐sugar medium simulating high‐gravity fermentation. Among the strains examined, the DBF2‐overexpressing bottom‐fermenting yeast strain exhibited the highest ethanol tolerance and fermentation rate in YPM20 medium. Using this strain, high‐gravity fermentation was performed by adding sugar to the wort, which led to increased fermentation rates and yeast viability compared with the parent strain. These findings indicate that V‐ATPase is a stress target in high‐gravity fermentation and suggests that enhancing the V‐ATPase activity increases the ethanol tolerance of bottom‐fermenting yeast, thereby improving the fermentation rate and cell viability under high‐gravity conditions. Copyright © 2012 The Institute of Brewing & Distilling     

Efficient Neuroprotective Rescue of Sacsin-Related Disease Phenotypes in Zebrafish

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a multisystem hereditary ataxia associated with mutations in SACS, which encodes sacsin, a protein of still only partially understood function. Although mouse models of ARSACS mimic largely the disease progression seen in humans, their use in the validation of effective therapies has not yet been proposed. Recently, the teleost Danio rerio has attracted increasing attention as a vertebrate model that allows rapid and economical screening, of candidate molecules, and thus combines the advantages of whole-organism phenotypic assays and in vitro high-throughput screening assays. Through CRISPR/Cas9-based mutagenesis, we generated and characterized a zebrafish sacs-null mutant line that replicates the main features of ARSACS. The sacs-null fish showed motor impairment, hindbrain atrophy, mitochondrial dysfunction, and reactive oxygen species accumulation. As proof of principle for using these mutant fish in high-throughput screening studies, we showed that both acetyl-DL-leucine and tauroursodeoxycholic acid improved locomotor and biochemical phenotypes in sacs^−/− larvae treated with these neuroprotective agents, by mediating significant rescue of the molecular functions altered by sacsin loss. Taken together, the evidence here reported shows the zebrafish to be a valuable model organism for the identification of novel molecular mechanisms and for efficient and rapid in vivo optimization and screening of potential therapeutic compounds. These findings may pave the way for new interventions targeting the earliest phases of Purkinje cell degeneration in ARSACS.     

Polymerization of 1,3‐dienes containing functional groups: 8. Free‐radical polymerization of 2‐triethoxysilyl‐ 1,3‐butadiene

The presence of a bulky substituent at the 2‐position of 1,3‐butadiene derivatives is known to affect the polymerization behavior and microstructure of the resulting polymers. Free‐radical polymerization of 2‐triethoxysilyl‐1,3‐butadiene ( 1 ) was carried out under various conditions, and its polymerization behavior was compared with that of 2‐triethoxymethyl‐ and other silyl‐substituted butadienes. A sticky polymer of high 1,4‐structure ( ) was obtained in moderate yield by 2,2′‐azobisisobutyronitrile (AIBN)‐initiated polymerization. A smaller amount of Diels–Alder dimer was formed compared with the case of other silyl‐substituted butadienes. The rate of polymerization (R_p) was found to be R_p = k[AIBN]^0.5[ 1 ]^1.2, and the overall activation energy for polymerization was determined to be 117 kJ mol^?1. The monomer reactivity ratios in copolymerization with styrene were r ₁ = 2.65 and r_st = 0.26. The glass transition temperature of the polymer of 1 was found to be ?78 °C. Free‐radical polymerization of 1 proceeded smoothly to give the corresponding 1,4‐polydiene. The 1,4‐E content of the polymer was less compared with that of poly(2‐triethoxymethyl‐1,3‐butadiene) and poly(2‐triisopropoxysilyl‐1,3‐butadiene) prepared under similar conditions. Copyright © 2010 Society of Chemical Industry     

Photocatalytic degradation of methylene blue by Au-deposited TiO<Subscript>2</Subscript> film under UV irradiation

A TiO₂ photocatalytic film was prepared by the sol–gel and dip-coating methods. Au-loaded TiO₂ photocatalytic films were produced by the photodeposition method. The photocatalytic activity of the films under UV irradiation was evaluated by measuring the degradation of absorbance for a methylene blue (MB) aqueous solution. Au particles deposited on the TiO₂ film improved the photocatalytic activity under the O₂ bubbling condition. On the other hand, under N₂ or Ar bubbling, the doubly reduced form of MB, leuco-methylene blue (LMB), was formed at the beginning of UV irradiation, and then both MB and LMB were decomposed gradually by the photocatalytic reaction. In this process, Au particles on the TiO₂ film behave as electron traps.     

Clarification of EDM gap phenomena using transparent electrodes

This paper describes the heat source diameter of single pulse discharge in electrical discharge machining. To observe the discharge plasma, SiC and Ga₂O₃ single crystals were used as the electrode material since they are optically transparent and electrically conductive. It was found that plasma diameter expands within a few microseconds after dielectric breakdown and the plasma diameter is much larger than the discharge crater. From the measured diameter of the crater, the heat source diameter was obtained by solving the inverse problem of heat conduction analysis, and it was found that the heat source diameter is smaller than the plasma diameter but larger than the crater diameter.     

Fracture process of thermally shocked discontinuous fibre-reinforced glass matrix composites under tensile loading

Fracture mechanisms of discontinuous carbon-fibre-reinforced glass matrix composites were experimentally studied for specimens with initial damage induced by thermal shock. First, matrix cracking due to thermal shock was observed using both optical microscopy and scanning acoustic microscopy (SAM) to reveal the damage state. Secondly, tensile stress-strain behaviour and acoustic emission during tensile tests were measured for specimens with and without thermal shock. The progress of microscopic damage during tensile loading was also investigated using both replica and in-situ SAM techniques. Finally, macroscopic transient thermal stresses during thermal shock were calculated using finite-element analysis. It is proved that the fracture process of the composite specimen with thermal-shock-induced cracks is different from that of the virgin specimen. This difference in fracture processes is attributed to the difference in the evolution of matrix cracking, which is affected by pre-existing microcracks in the matrix. This revised version was published online in November 2006 with corrections to the Cover Date.     

Ultrasonic Noise Relaxation for Evaluating Thermal Aging Embrittlement of Duplex Stainless Steels

A noncontact ultrasonic method is presented to evaluate the thermal aging embrittlement of the cast duplex stainless steels, which uses the shear-wave backscattering noise detected by an electromagnetic acoustic transducer (EMAT). Duplex stainless steel is a highly damping material, and the pulse-echo measurement for the velocity and attenuation is unavailable. High damping comes from the scattering at boundaries between the austenitic and ferritic phases. But, since little energy is absorbed in the material, the elastic waves impinged by an EMAT last in the sample for a long period (in the order of 10 ms) and are received by the same EMAT as a slowly decaying backscattering noise. The relaxation time coefficient is calculated by integrating the digitized noise signal and is correlated with the aging time. It clearly discriminates four duplex stainless steels aged for 0, 300, 1000, and 3000 h at 673K. The noise decays in a shorter time as the aging period increases. The difference of the noise relaxation rate is interpreted by the phase decomposition of ferrite into Cr-rich α' phase and Fe-rich α phase as supported by transmission electron microscopy (TEM).     

Characterization of oil produced by the direct liquefaction of Japanese oak in an aqueous 2-propanol solvent system

The heavy oil produced in the alkali catalyzed thermal liquefaction of Japanese Oak in the aqueous organic alcohol solvent system of water/2-propanol was partially characterized using an acid base fractionation and GC-MS. The acidic fraction comprised 25–30% of the recovery, and the neutral material was 13–20%. The amount of basic material was less than 1% of the original material. Proton and carbon NMR and the GC-MS identification of the composition of these fractions confirmed the presence of about 25% aromatics with most of the aromatics being mono- or di-substituted.