A 100 Gram‐Scale Production of a Key Building Block of Antibacterial Vancomycin: The Use of an Air‐Stable Chiral Zirconium Catalyst and Complete Recovery of a Silicon Source in Catalytic Asymmetric Mukaiyama Aldol Reaction

We have achieved a 100 gram‐scale production of anti‐(2S,3S)‐β‐(p‐benzyloxy‐m‐chloro)phenyl‐N‐trifluoroacetyl‐L ‐serine methyl ester ( 1 ) in high yield with high diastereo‐ and enantioselectivities based on a catalytic asymmetric Mukaiyama aldol reaction. The use of an air‐stable zirconium‐molecular sieves combined catalyst [(R)‐I₄‐ZrMS] facilitates easy manufacturing operation and reproducibility. Moreover, this is the first example of the complete recovery of the silicon source in a Mukaiyama aldol reaction.     

Disinfection of Legionella pneumophila by ultrasonic treatment with TiO2

An ultrasonic treatment system, using a TiO₂ photocatalyst, was used to disinfect Legionella pneumophila. A kinetic study of the process indicates that TiO₂ significantly improves the disinfection process. The concentrations of viable cells were reduced to 6% of the initial concentrations in the presence of 0.2 g/ml TiO₂ after a 30 min of treatment period, while only an 18% reduction was observed in the absence of TiO₂. The potency of the disinfection could be enhanced, to some extent, by increasing the amount of TiO₂ used. Cell concentrations were decreased by an order of 3 within 30 min of treatment in the presence of 1.0 g/ml TiO₂. The disinfection power in the presence of TiO₂ versus Al₂O₃ was also compared and the findings showed that TiO₂ induced a higher cell killing. No significant effect of initial cell concentration on the disinfection was found in the range of 10²-10⁷ CFU/ml after a 30 min of treatment period. The mechanism of cell killing was investigated by examining the effects of OH radical scavengers such as ascorbic acid, histidine and glutathione. The disinfection power was reduced in samples that contained these radical scavengers, thus indicating the importance of OH radicals.     

Gallium Trichloride‐Catalyzed Exhaustive α‐Ethynylation Reaction of 1‐Silylacetylenes

Gallium trichloride (GaCl₃) catalyzes the ethynylation reaction of a 1,4‐enyne with chlorosilylacetylene at the propargyl position giving a triethynylvinylmethane. This catalytic method can be applied to the exhaustive α‐ethynylation of 1‐silylacetylenes possessing less acidic propargyl protons, and mono‐, di‐, and triethynylated products are obtained depending on the structure of the starting materials.     

A multigigabit DRAM technology with 6F2 open-bitlinecell, distributed overdriven sensing, and stacked-flash fuse

A multigigabit DRAM technology was developed that features a low-noise 6F² open-bitline cell with fully utilized edge arrays, distributed overdriven sensing for operation below 1 V, and a highly reliable post-packaging repair scheme using a stacked-flash fuse. This technology, which can be used to fabricate a 0,13-μm 180-mm² 1-Gb DRAM assembled in a 400-mil package, was verified using a 57.6-mm², 200-MHz array-cycle, 256-Mb test chip with 0.109-μm² cells     

Application of equal channel angular extrusion on strengthening of ferritic stainless steel

SUS430 ferritic stainless steel was subjected to equal channel angular extrusion (ECAE) at room temperature to a total strain of 2.3. It was shown that the sample processed by ECAE showed higher room temperature strength than the as-quenched sample. This is probably due to the heavily worked structure. On the other hand, annealing at 673 K and 773 K increased both strength and elongation of the ECAE processed sample. It is likely that higher strength is attributed to both the worked structure and fine substructures. It is also likely that higher elongation is attributed to the fine substractures. It is concluded that a combination of ECAE with annealing is available for improving the room temperature tensile properties of SUS430.     

Microbial synthesis and properties of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)

Microbial synthesis of copolymers of [R]-3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB), P(3HB-co-4HB), by Alcaligenes eutrophus, Alcaligenes latus, and Comamonas acidovorans from various carbon sources has been studied. The copolyester compositions varied from 0 to 100 mol% 4HB, depending on the microorganism and the combination of carbon substrates supplied. The thermal and physical properties of compositions with 0–100 mol% 4HB were investigated. The copolyesters represented a wide variety of polymeric materials, from hard crystalline plastic to very elastic rubbers, depending on composition. The copolyester films with high 4HB fractions (64–100 mol% 4HB) exhibited the characteristics of a thermoplastic elastomer, and the tensile strength increased from 17 to 104 MPa as the 4HB fraction increased. The enzymatic degradation of P(3HB-co-4HB) films was studied in an aqueous solution of extracellular polyhydroxybutyrate (PHB) depolymerase from Alcaligenes faecalis or lipase from Rhizopus delemer. The erosion rate of P(3HB-co-4HB) films was strongly dependent on the copolymer composition. In addition, environmental degradation of P(3HB-co-4HB) films in sea water was investigated.     

Effects of solid lubricants in backward extrusion

In the present paper, some solid lubricants were tested in backward extrusion friction tests with flat-headed punches using aluminium at room temperature. The results showed that anti-seizure ability was improved when wax was added to the solid lubricant samples. In addition, a water-based graphite lubricant and an ultrahigh molecular weight polyethylene (UHMW-PE) lubricant were tested using aluminium workpieces heated to 500°C. The lubricity of the UHMW-PE lubricant was found to be superior to that of the graphite lubricant.     

Effects of the degree of crosslinking and test rate on the tensile properties of a crosslinked polyacrylic pressure-sensitive adhesive and vulcanized rubber

The effects of the tensile test rate on the properties of a pressure-sensitive adhesive (PSA) and of vulcanized rubber were ascertained and compared, using a poly(n-butyl acrylate-acrylic acid) random copolymer with varying degrees of crosslinking as the PSA. The 100% modulus of the PSA was found to increase along with the crosslinking degree and with faster tensile test rates. In contrast, the 100% modulus of the vulcanized rubber did not exhibit any test rate dependence. To assess this effect, the molecular weights between chemical and physical crosslinking points were determined via equilibrium swelling, dynamic mechanical analysis, and tensile tests. The proportion of physical crosslinking points was found to be far larger in the crosslinked PSA. Because these entanglement points can readily disentangle in response to slow deformation, variations in the test rate only affected the PSA. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47272.     

Immuno‐detection of mRNA‐binding protein complex in human cells under transmission electron microscopy

Transit from the nuclear complex to the cytoplasm through the nuclear pore complex permits modification of mRNA, including processing such as splicing, capping, and polyadenylation, etc. At each of these events, mRNA interacts with various proteins to form mRNA‐protein complex. Visualizing the mRNA is crucial for understanding the mechanisms underlying mRNA processing and elucidating its structure and recent advances in mRNA imaging allow detection of real‐time mRNA localization in living cells. However, these techniques revealed only the location of mRNA but cannot visualize the conformation of mRNA‐protein complex in cells. On the other hand, transmission electron microscopy has been used to visualize the structure of the Balbiani ring‐derived large mRNA, but their observations were limited to the insect cells. In this study, we visualized the structure of mRNA‐protein complex in human culture cells by using immuno‐electron microscopy. Through immuno‐detection, an mRNA exon junction binding complex Y14, and its binding protien Upf2, different gold particle patterns were imaged with transmission electron microscopy and analyzed. Characteristic linear and stacked particle orientation were observed. Across the nuclear membrane, only linear aggregation pattern was observed, whereas the stacked aggregation pattern was detected in the cytoplasm. Our method is able to visualize mRNA‐conformation and applicable to many cell types, including mammalian cells, where genes can easily be manipulated.