Melting Point Elevation of Isotactic Polypropylene

The melting point of a conventional isotactic polypropylene (PP) was enhanced by a rapid annealing procedure of an extruded sheet composed of β trigonal form crystals having thick lamellae, which was prepared by T-die processing with a specific β-nucleating agent, N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide. Although the melting point of PP with α monoclinic form, prepared by a conventional processing method, is known to be located around at 165°C, the sample obtained by the present technique showed a higher melting point, 170°C. The phase transformation from β-to α-form crystals, retaining the lamellar thickness, was responsible for the melting point elevation.     

Fast Calculation of Computer-Generated Fresnel Hologram Utilizing Distributed Parallel Processing and Array Operation

Fresnel CGH for a three-dimensional (3-D) object is generated by calculating the Fresnel diffraction, but it requires a huge amount of calculation. This is one reason for the difficulty in realizing real-time holography. We propose fast calculation method of computer-generated Fresnel hologram (Fresnel CGH) utilizing distributed parallel processing and array operation. In our method, a projected image with depth information of the 3-D object is prepared to calculate the Fresnel diffraction. The Fresnel diffraction of the projected image is then calculated with depth information by array operation and distributed parallel processing. Parallel processing is realized using JavaSpaces and many standard computers. In our array operation, calculation error in phase distribution on a hologram occurs more than the strict Fresnel diffraction. However, it was confirmed by experiments that the influence of an error can be controlled and ignored. In this paper, our proposed method and some experimental results are shown.     

Improvement in reliability of probabilistic test of significant differences in GeneChip experiments.

A probabilistic test (FUMI theory) for GeneChip experiments has been proposed for selecting the genes which show significant differences in the gene expression levels between a single pair of treatment and control. This paper describes that the reliability of the judgment by the FUMI theory can be enhanced, when the selected genes are referred to biomolecular-functional networks of a commercial database. The genes judged as being differently expressed are grouped into a cluster in the biomolecular networks. It is also demonstrated that false positive genes have a trend in the networks to be isolated from each other, and also away from the clustered genes, since the false positive genes are randomly selected.     

Theoretical analysis of concerted and stepwise mechanisms of the hetero-Diels–Alder reaction of butadiene with formaldehyde and thioformaldehyde

The concerted and stepwise mechanisms of the hetero-Diels–Alder reaction of butadiene with formaldehyde and thioformaldehyde were studied by a CASSCF molecular orbital method. The energy barrier of the concerted reaction of butadiene with formaldehyde is about 21 kcal/mol higher than that of butadiene with thioformaldehyde at the CAS-MP2 calculation level. For the stepwise reaction paths, the energy barrier for the first step process of the reaction of butadiene with formaldehyde is about 17 kcal/mol above that of butadiene with thioformaldehyde. The concerted pathways for both systems are more favorable by 9–12 kcal/mol than the stepwise pathways. The electronic mechanisms for the concerted reactions of both reaction systems are also discussed by a CiLC analysis.     

A Cold-Adapted and Organic Solvent-Tolerant Lipase from a Psychrotrophic Bacterium Pseudomonas sp. Strain YY31: Identification, Cloning, and Characterization

A novel cold-adapted lipase (designated as LipYY31) was obtained from a psychrotrophic Pseudomonas sp. YY31. The strain YY31 was gram-negative, rod shaped, motile by means of one polar flagellum, and exhibited chemotaxis toward oil droplets under a microscope. The strain displayed remarkable degradation of edible oil and fat even at 5 °C. The LipYY31 DNA fragment contains an open reading frame of 1,410 bp which encoded a protein of 470 amino acids with an estimated molecular mass of 49,584 Da. LipYY31 showed high sequence similarity to those of subfamily Ι.3 lipase and had a conserved GXSXG motif around the catalytic Ser residue. Its optimal temperature was 25–30 °C, and it retained 20–40 % of its activity at 0–5 °C. The optimal pH value was 8.0. The activity was strongly inhibited by Cd²⁺, Zn²⁺, EDTA and was highly dependent on Ca²⁺. Tricaprin and p-nitrophenyl caprate were the most favorable substrates among the triglycerides and p-nitrophenyl esters, respectively. LipYY31 also had high activity towards natural substrates including edible vegetable oils and animal fat. Furthermore, LipYY31 was very active and stable in the presence of several detergents and organic solvents. In particular, the lipase exhibited high stability against organic solvents such as methanol, ethanol, and isopropanol.     

Significance of water quality and radiation wavelength for UV photolysis of PhCs in simulated mixed solutions

Ultraviolet (UV) photolysis of sixteen pharmaceutical compounds (PhCs) in mixed solutions with four types of water and two sets of UV radiation was investigated. UVC (254 nm) photolysis was ineffective at eliminating a large number of PhCs while a big number of them were refractory. However, vacuum UV (VUV: 185 nm + 254 nm) photolysis in the same experimental conditions eliminated the PhCs almost completely. The eliminations in ultrapure water (UPW), tap water (TW) and Neya River water (NRW) and their organic/inorganic contents were inversely correlated, which was more evident in VUV photolysis. Natural organic matter (NOM) in NRW did not have an impact in indirect photolysis, but effluent organic matter (EfOM) in secondary-treated effluent (NWTPE) enhanced indirect photolysis, which was more evident in VUV photolysis underlining the point that radiation wavelength/intensity can be a limiting factor in organic-rich waters. Moreover, VUV photolysis was far superior (90% mineralization) to UVC photolysis (10% mineralization) for PhCs mineralization. The greatly enhanced elimination and mineralization efficiencies observed for VUV photolysis were attributed to accelerated direct photolysis with 185 nm wavelength and indirect photolysis involving ^·OH. The results demonstrated efficacy of VUV photolysis in wastewater treatment and its potential use as a tertiary treatment.      

Small-angle neutron scattering study on the miscibility and concentration fluctuation of hydrogen-bonded polymer blends

Thermal concentration fluctuation in the blends of deuterated poly(ethylene oxide) (dPEO) and poly(vinyl acetate-co-vinyl alcohol) [P(VAc-VOH)] with various VOH contents f_OH were examined by small angle neutron scattering techniques at a fixed blend composition, dPEO/P(VAc-VOH) = 20/80 which is close to the critical composition. Blends at the highest f_OH (=0.35) showed a non-Lorentzian scattering profile: specifically the scattering intensities at the low q (angle) region were suppressed compared to those expected from the random phase approximation (RPA) theory. However, for the blends at lower f_OH (≤0.28), the profiles could be represented by the RPA. Using the RPA we determined effective values of the Flory-Huggins interaction parameter χ_eff as a function of f_OH (=0–0.28). The χ_eff showed the minimum around f_OH = 0.1–0.18 meaning the highest miscibility of the blend at these f_OH. On the basis of the random copolymer theory, we evaluated the three interaction parameters χ_Ac–EO, χ_EO–OH, and χ_Ac–OH separately from the χ_eff(f_OH) and found the order of magnitude; χ_Ac–EO < 0 < χ_EO–OH < χ_Ac–OH. The largest positive χ_Ac–OH showing intrachain interaction in the P(VAc-VOH) copolymer was concluded to be the origin of the enhanced miscibility at around f_OH = 0.1–0.18. On the basis of the Coleman and Painter's theory, the effects of hydrogen bonding on these three χ_A-B were discussed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2556–2565, 2008     

Kinetic studies of rigid copolymers containing 3,3′-substituted biphenyls and vinylimidazole

Kinetic studies were investigated with rigid copolymers composed of vinylimidazole (VIm) and 3,3′-substituted biphenyls. For neutral substrates, two different kinetic figures were observed by the influence of 3,3′-substituents. The second-order rate constants kinetically determined were largely enhanced by the reduction of ethanol content less than 30 vol % in contrast to the rapid decrease in viscosities of catalyst solutions. A parameter concerning the polymer conformation and the effect of hydrophobic interaction was obtained using a relationship between the kinetic constants with ethanol content. Maximum kinetic effect of electrostatic interaction appeared at about 50 mole % VIm content by attracting cationic substrates towards the COO^? group of the polymer catalyst. This maximum rate profile was nearly coincident with a curve derived by calculating the sequence distribution of the (VIm? COOH) linkage unit.