Pressure effect on bulk weak ferromagnets: (BDH-TTP)[M(isoq)2(NCS)4] (M = Cr(III), Fe(III); isoq = Isoquinoline)

The pressure dependence of the magnetic properties of weak ferromagnets (BDH-TTP)[M(isoq)2(NCS)4] [BDH-TTP = 2,5-bis(1',3'-dithiolan-2'-ylidene)-1,3,4,6-tetrathiapentalene; M = Cr, Fe; isoq = isoquinoline] is discussed. These salts form two-dimensional magnetic sheets, where ferrimagnetic chains of donor cation radical (S = 1/2) and anion [S = 3/2 (Cr), 5/2 (Fe)] are antiferromagnetically connected by weak donor-donor and anion-anion interchain S...S contacts. Under ambient pressure, both the Cr and Fe salts undergo a weak ferromagnetic transition at Tc = 7.6 K, below which a spontaneous magnetization emerges along the direction perpendicular to the sheets. The application of the pressure elevates the transition temperatures up to 16.6 and 11.6 K at 9 kbar for M = Cr and Fe, respectively. As the pressure increases, the remanent magnetization M(r) decreases, whose pressure dependence for the Cr salt is larger than that for the Fe salt. This difference indicates that the spin-canting angle of the Cr salt is reduced because of the increase of antiferromagnetic interaction by applied pressure, in contrast to the Fe salt, where single-ion anisotropy contributes less. The quantitative analysis of the magnetization curves of the Cr salt using the mean-field approximation reveals that the intermolecular exchange interaction increases as the pressure increases, among which the interchain anion-anion interaction has the highest pressure sensitivity. This result is consistent with the temperature dependence of the crystal structure showing that the thermal contraction in the distances of interchain anion-anion S...S contacts is the most remarkable in intrachain S...S contacts. The large pressure dependence of the transition temperature of these salts is therefore explained as a result of the fact that the interchain interactions, the anion-anion interaction in particular, are strengthened by applied pressure.     

Pressure effect on the electrical conductivity and superconductivity of beta-(BDA-TTP)2I3

The pressure-induced electrical conductivity properties of beta-(BDA-TTP)2I3 have been investigated; the salt exhibits a dramatic change in the conductivity behaviour above ca. 10 kbar and undergoes a superconducting transition with an onset near 10 K.     

Catalytic four-component assembly based on allenylboronate platform: new access to privileged allylic amine structures

We developed a novel palladium-catalyzed four-component assembly based on allenylboronate platform, by which privileged allylic amine structures can be constructed in a regioselective, stereoselective, and diversity-oriented manner. The boryl group acts not only as a useful group that can be transformed to various functional groups afterward but also as a stereochemical controller in the generation of key (pi-allyl)palladium intermediates. A short synthesis of rolipram (selective phosphodiesterase-4 inhibitor) is also demonstrated.     

Marine Diatom, Navicula sp. Strain JPCC DA0580 and Marine Green Alga, Chlorella sp. Strain NKG400014 as Potential Sources for Biodiesel Production

Marine diatom, strain JPCC DA0580, and marine green microalga strain NKG400014 were selected as high neutral lipid-producers from marine microalgal culture collection toward biodiesel production. These strains were tentatively identified as Navicula sp. and Chlorella sp., respectively, by 18S rDNA analysis. Growth and lipid accumulation conditions of both strains were analyzed by changing nutrient concentrations in growth media and initial illuminance intensity. The highest productivity of fatty acid methyl ester (FAME) reached to 154 mg/L/week for NKG400014 and 185 mg/L/week for JPCC DA0580. Gas chromatography/mass spectrometry analysis indicates that FAME fraction from NKG400014 mainly contained 9-12-15-octadecatrienoate (C18:3) and that from JPCC DA0580 mainly contained methyl palmitate (C16:0) and methyl palmitoleate (C16:1). Furthermore, calorimetric analysis revealed that the energy content of strain was 4,233?±?55 kcal/kg (i.e., 15.9?±?0.2 MJ/kg) for NKG400014 and 6,423?±?139 kcal/mg (i.e., 26.9?±?0.6 MJ/kg) for JPCC DA0580, respectively. The value from JPCC DA0580 was equivalent to that of coal. The strains NKG400014 and JPCC DA0580 will become a promising resource that can grow as dominant species in the open ocean toward production of both liquid and solid biofuels.     

Asymmetric synthesis of cyclic α-amino acid derivatives by the intramolecular reaction of magnesium carbenoid with an N-magnesio arylamine

The synthesis of pipecolic acid and homopipecolic acid derivatives was developed from ω-(2-aminophenyl)-1-chloroalkyl p-tolyl sulfoxides by treatment with i-PrMgCl. An intramolecular nucleophilic substitution reaction of a magnesium carbenoid with an N-magnesio arylamine is the key step of this reaction. Proline and pipecolic acid derivatives were also synthesized from ω-(arylamino)-1-chloroalkyl p-tolyl sulfoxides by the same chemistry. Starting from enantiomerically pure (1S,R_S)-1-chloro-3-[2-(N-methylamino)phenyl]propyl p-tolyl sulfoxide, enantiomerically pure (R)-pipecolic acid derivative was obtained. The intramolecular nucleophilic substitution reaction of the magnesium carbenoid with N-magnesio arylamine was proven to take place with inversion of the carbenoid carbon. The stereochemistry of these reactions is also discussed.     

Labeling the planar face of crystalline cellulose using quantum dots directed by type-I carbohydrate-binding modules

We report a new method for the direct labeling and visualization of crystalline cellulose using quantum dots (QDs) directed by carbohydrate-binding modules (CBMs). Two type-I (surface binding) CBMs belonging to families 2 and 3a were cloned and expressed with dual histidine tags at the N- and C-termini. Semiconductor (CdSe)ZnS QDs were used to label these CBMs following their binding to Valonia cellulose crystals. Using this approach, we demonstrated that QDs are linearly arrayed on cellulose, which implies that these CBMs specifically bind to a planar face of cellulose. Direct imaging has further shown that different sizes (colors) of QDs can be used to label CBMs bound to cellulose. Furthermore, the binding density of QDs arrayed on cellulose was modified predictably by selecting from various combinations of CBMs and QDs of known dimensions. This approach should be useful for labeling and imaging cellulose-containing materials precisely at the molecular scale, thereby supporting studies of the molecular mechanisms of lignocellulose conversion for biofuels production.     

Interfaces for 1-D degenerate Keller–Segel systems

Let us consider the Keller–Segel system of degenerate type (KS) _m with m >1 below. We prove the property of finite speed of propagation for weak solutions u with a certain regularity. Moreover, we investigate the interface curve which separates the regions and . Concretely, we characterize the interface curve as the solution of a certain ordinary differential equation associated with (KS) _m .     

Relationships between power-law long-range interactions and fractional mechanics

We investigate the relationships between models of power-law long-range interactions and mechanics based on fractional derivatives. We present the fractional Lagrangian density which gives the Euler–Lagrange equation that serves as the equation of motion for fractional-power-law long-range interactions. We derive this equation by the fractional variational method. In addition, we derive a Noether-like current from the fractional Lagrangian density.     

Fabrication of high aspect ratio subwavelength gratings based on X-ray lithography and electron beam lithography

In this paper, we present two nano-fabrication technologies that provide effective approaches for low-cost, large-scale manufacturing of nano-gratings. One grating is fabricated on polymethylmethacrylate (PMMA) with the pitch of 500 nm, and height of 2000 nm, and the other is fabricated on silicon wafer with the pitch of 666 nm, and height of 200 nm. High aspect ratio PMMA nanostructures which use X-ray lithography and electron beam lithography (EBL) are reported in this paper. These gratings can be used as molds, making it possible for industrial nano-imprinting technology to significantly cut cost and shorten process time.     

An interface capturing method with a continuous function: The THINC method with multi-dimensional reconstruction

An interface capturing method with a continuous function is proposed within the framework of the volume-of-fluid (VOF) method. Being different from the traditional VOF methods that require a geometrical reconstruction and identify the interface by a discontinuous Heaviside function, the present method makes use of the hyperbolic tangent function (known as one of the sigmoid type functions) in the tangent of hyperbola interface capturing (THINC) method [F. Xiao, Y. Honma, K. Kono, A simple algebraic interface capturing scheme using hyperbolic tangent function, Int. J. Numer. Methods Fluids 48 (2005) 1023–1040] to retrieve the interface in an algebraic way from the volume-fraction data of multi-component materials. Instead of the 1D reconstruction in the original THINC method, a multi-dimensional hyperbolic tangent function is employed in the present new approach. The present scheme resolves moving interface with geometric faithfulness and compact thickness, and has at least the following advantages: (1) the geometric reconstruction is not required in constructing piecewise approximate functions; (2) besides a piecewise linear interface, curved (quadratic) surface can be easily constructed as well; and (3) the continuous multi-dimensional hyperbolic tangent function allows the direct calculations of derivatives and normal vectors. Numerical benchmark tests including transport of moving interface and incompressible interfacial flows are presented to validate the numerical accuracy for interface capturing and to show the capability for practical problems such as a stationary circular droplet, a drop oscillation, a shear-induced drop deformation and a rising bubble.