A convenient preparative method of unsymmetrical ketones and aliphatic aldehydes by thermolysis of homoallylic alcohols

The thermolyses of various homoallylic alcohols, which are prepared from 1-alken-4-ones (B) by Grignard reaction or reduction, afforded unsymmetrical ketones or aliphatic aldehydes in good yields. For example, the reaction of methylmagnesium iodide with 1-nonen-4-one (1) gave 4-methyl-1-nonen-4-ol (2) in 87% yield. The thermolysis of (2) at the temperature of 753 K gave 2-heptanone (3) in 92% yield. By use of this method, we obtained a variety of 1-alken-5-ones (J) which can be used as important intermediates of the preparation for dihydrojasmone or cis-jasmone.     

Electrical conductivity of acidic chloride solutions

The electrical conductivities of aqueous solutions in the system HCl-MCl_n (where M = K, Na, Mg, Ni, or Cd) were measured at different temperatures. The equivalent electrical conductivity of H⁺ was calculated on the basis of simple assumptions for these solutions, and show an inverse relationship with water activity in these solutions. The results obtained by varying temperatures, solute ratios, and ionic strength on the electrical conductivity were found to be consistent with a proton jump mechanism for the H⁺ ion, where the activity of water is the most significant parameter affecting its equivalent conductance, and a viscous (Stokes’ law) drag mechanism (i.e., Walden’s rule is obeyed) for other ions found in acidic solutions.     

Effect of addition of saccharose on gelation of aqueous poly(vinyl alcohol) solutions

The properties of poly(vinyl alcohol) (PVA) hydrogels containing saccharose were examined. The effect of the addition of saccharose to atactic PVA (α-PVA) gels on their melting temperatures was larger than that for syndiotacticity-rich PVA (s-PVA) gels and the melting temperature was above 100°C for α-PVA gels with saccharose contents of 60 wt %. However, the fusion enthalpy (ΔH) of the α-PVA gels was at most 100 kJ/mol. The release of solvent (water/saccharose) from gels in air decreased with an increase in the saccharose content and the equilibrium was achieved after standing for 20 days for the α-PVA and s-PVA gels with saccharose contents above 40 and 20 wt %, respectively. © 1995 John Wiley & Sons, Inc.     

Anomalous behavior of electrical conductivity of solubilized collagen solutions with thermal denaturation

The temperature dependence of the electrical conductivity, σ, for a collagen solution was measured in the temperature region including the thermal denaturation temperature, t_d. The σ increased with temperature, t, but decreased at ca. 40°C, and then again increased. In this temperature region, a change of optical rotation, α_D, was observed. The change is due to the thermal denaturation. The differential curve of σ vs. t gave clear deflection points and a large peak at ca. 40°C. The t_d could be estimated from the peak temperature. The t_d decreased with the increase in the concentration of collagen and with the decrease in the heating rate. These measurements were carried out for the collagen prepared by various methods. Some of them showed one peak; others had two peaks. The t_d obtained by the measurement of σ correlated with that obtained by the measurement of α_D. The activation energy of σ, ΔE_a, obtained from the linear relationship between log σ and 1/T, increased with the concentration of collagen, but was unchanged for the heating rate. The ΔE_a obtained for various types of collagen showed a constant value. © 1993 John Wiley & Sons, Inc.     

Impulse dispersion in a tapered granular chain

 This paper describes a unique way to disperse an impulse in granular material. A number of chrome steel balls are arranged in a chain formation with monotonically decreasing size. The incoming impulse is received by the largest ball at one end and propagates through the chain. Due to translation symmetry breaking, the classical solitary wave known to develop in a chain of particles of the same size quickly lose its signature, disperses itself throughout the balls in the chain, and finally manifests itself as a collection of smaller impulses. This paper presents experimental confirmation of this mechanism and a comparison with recent theoretical predictions of impulse dispersion in a chain of hard inelastic spheres. Some discrepancies with theory are interpreted in terms of energy transfer to rotational degrees of freedom. Received: 29 August 2002     

Synthesis of rewrite programs by higher-order and semantic unification

This paper presents a framework for synthesizing rewrite programs using higher-order and semantic unification. Many problems in computer science and artificial intelligence can be formalized as problems of higher-order unification. Among such problems is first-order anti-unification. In this paper, we show that first-order anti-unification can be regarded as a second-order matching problem and solved by the algorithm for higher-order unification.     

Bacterioplankton production in a water column of Lake Biwa

Seasonal production of bacterioplankton in a water column of Lake Biwa was examined based on cell‐specific growth rates at above (surface layer) and below the thermocline (deep layer). The growth rates were estimated by incubating bacterioplankton in situ with a dilution technique. The rates ranged from 0.05 per day in winter to 0.89 per day in summer, generally with much higher rates in the surface layer than in the deep layer. In an entire water column, bacterial production (in terms of carbon [C]) ranged from 0.217 to 0.811 gC/m² per day with a mean of 0.451 gC/m² per day, which, on average corresponded to 43% of primary production. However, no significant correlation was detected between bacterial production and primary production rates. Although the bacterial production rate correlated positively to water temperature, surface and deep layer rates were comparative for some dates because the deep layer shared a large fraction of the water column. These results suggest that, although specific bacterial activity was low in the deep layer due to the low temperature, bacteria in that layer play substantial roles in consumption of organic matter and material flows in Lake Biwa.     

Transesterification of oil by fatty acid-modified lipase

Fatty acid was covalently attached to lipase (EC 3.1.1.3.) fromPhycomyces nites, yielding a modified lipase of higher specific activity in hydrolytic and synthetic reactions in organic solvents. Attached long-chain fatty acids solubilized the lipase in organic solvent and, therefore, promotion of dispersibility in organic solvent resulted in much higher reactivity. The initial rate of transesterification by modified lipase was almost 40 times that of native lipase in organic solvent. The specificities and selectivity of the modified lipase depended on the kind of attached fatty acid.     

Molecular Robotics: A New Paradigm for Artifacts

The rapid progress of molecular nanotechnology has opened the door to molecular robotics, which uses molecules as robot components. In order to promote this new paradigm, the Molecular Robotics Research Group was established in the Systems and Information Division of the Society of Instrument and Control Engineers (SICE) in 2010. The group consists of researchers from various fields including chemistry, biophysics, DNA nanotechnology, systems science and robotics, challenging this emerging new field. Last year, the group proposed a research project focusing on molecular robotics, and it was recently awarded a Grant-in-Aid for Scientific Research on Innovative Areas (FY2012-16), one of the large-scale research projects in Japan, by MEXT (Ministry of Education, Culture, Sports, Science and Technology, JAPAN). Here, we wish to clarify the fundamental concept and research direction of molecular robotics. For this purpose, we present a comprehensive view of molecular robotics based on the discussions held in the Molecular Robotics Research Group.     

Bounded hairpin completion

Hairpin completion is a formal operation inspired from biochemistry. Here we consider a restricted variant of hairpin completion called bounded hairpin completion. Applied to a word encoding a single stranded molecule x such that either a suffix or a prefix of x is complementary to a subword of x, hairpin completion produces a new word z, which is a prolongation of x to the right or to the left by annealing.Although this operation is a purely mathematical one and the biological reality is just a source of inspiration, it seems rather unrealistic to impose no restriction on the length of the prefix or suffix added by the hairpin completion. The restriction considered here concerns the length of all prefixes and suffixes that are added to the current word by hairpin completion. They cannot be longer than a given constant. Closure properties of some classes of formal languages under the non-iterated and iterated bounded hairpin completion are investigated. We consider the bounded hairpin completion distance between two words and generalize this distance to languages and discuss algorithms for computing them. Finally also the inverse operation, namely bounded hairpin reduction, as well as the set of all primitive bounded hairpin roots of a regular language are considered.