Construction and characterization of alkoxy-derived (Y,Yb)MnO<Subscript>3</Subscript>/HfO<Subscript>2</Subscript>/Si structures for FeRAM application

(Y,Yb)MnO₃ and HfO₂ films were prepared using alkoxy-derived precursor solutions, and (Y,Yb)MnO₃/HfO₂/Si structures were fabricated. The thickness, surface uniformity and crystallinity of the HfO₂ film affect the crystallization of Y_0.5Yb_0.5MnO₃ films. The degree of c-axis orientation and crystallinity of the Y_0.5Yb_0.5MnO₃ films were changed with preparation conditions of HfO₂ films. It was difficult to obtain Y_0.5Yb_0.5MnO₃ films with high crystallinity and high degree of c-axis orientation on the HfO₂ films thinner than 10 nm. The degree of c-axis orientation and crystallinity of the Y_0.5Yb_0.5MnO₃ films on HfO₂ films were improved by using diluted HfO₂ precursor solution in the case of 10 nm-thick HfO₂ film. Following this, the capacitance-voltage (C-V) characteristics were improved.     

Triethyl- (or trimethyl-)silyl triflate-catalyzed reductive cleavage of triphenylmethyl (trityl) ethers with triethylsilane

[reaction: see text] A triphenylmethyl (trityl) ether was reductively and instantaneously cleaved by triethylsilane in the presence of a catalytic amount of TES- (or TMS)-triflate. The reaction conditions are mild enough to achieve reduction in the presence of a variety of acid-sensitive functional groups. Upon a mild acidic treatment of the crude product, the corresponding alcohol is obtained in high yield.     

Stable equilibrium of systems of generalized Volterra type

In this paper, the global stability of systems of the generalized Volterra type:

$\text{dx}{}_{\mathrm{i}}\text{dt}\text{=x}{}_{\mathrm{i}}\text{∑}\text{j=1}\text{n}\text{a}{}_{\mathrm{ij}}\text{x}{}_{\mathrm{j}}\text{+b}{}_{\mathrm{i}}\text{, i=1,…,n.}$

is investigated. It is shown that a stable equilibrium point of (1) must be a solution of corresponding linear complementarity problem. Further, when the structure of (1) is restricted, the known stability condition is proved to be necessary and sufficient for the existence of a stable equilibrium point for every b?Rⁿ. Some structures satisfying these restrictions are given.     

Effect of amorphous TiO2 buffer layer on the phase formation of CaBi4Ti4O15 ferroelectric thin films

Amorphous buffer layers of TiO₂ were introduced between CaBi₄Ti₄O₁₅ thin films and Pt bottom electrodes through chemical solution deposition techniques. Several tens of nanometers thick alkoxy-derived TiO₂ layers were found to be critical for acceleration of the phase transition in the thin films. Unlike thin film crystallized directly onto a highly (111) oriented Pt bottom electrode, the thin film on an amorphous TiO₂ layer was almost single phase perovskite and showed random orientation. The crystallinity of the CaBi₄Ti₄O₁₅ thin film was much higher than that crystallized directly onto the Pt bottom electrode. The dielectric and ferroelectric properties of the CaBi₄Ti₄O₁₅/TiO₂ stacked thin films on Pt coated Si substrates are evaluated, leading to the potential of the amorphous buffer layer for the integrated devices being clarified. PACS 77.84.-s; 68.37.-d; 81.15.-z     

Total synthesis and morphogenesis-inducing activity of (±)-thallusin and its analogues

Total synthesis of (±)-thallusin was achieved using Hg(OTf)₂·PhNMe₂-induced olefin cyclization, and Suzuki coupling with a pyridylboronic acid derivative. Hg(OTf)₂ also acted as a catalyst to isomerize the double bond into the more thermodynamically stable isomer when treated in toluene. Synthetic (±)-thallusin as well as an analogue showed morphogenesis-inducing activity.     

A pyrazine-based fluorescence-enhancing ligand with a high selectivity for thymine in AP site-containing DNA duplexes

A fluorescent pyrazine derivative, 3,5-diamino-6-chloro-2-pyrazine carbonitrile (DCPC), is presented as a promising light-up ligand for single-nucleotide polymorphisms (SNPs) typing. In solutions buffered to pH 7.0 (I = 0.11 M, at 5 degrees C), DCPC can bind to thymine selectively over other nucleobases opposite an abasic site in DNA duplexes (5'-GTGTG CGTTG ANA TGGAC GCAGA-3'/3'-CACAC GCAAC TXT ACCTG CGTCT-5', X = abasic site, N = target nucleotide) with a dissociation constant of 2.6 microM. The binding of DCPC is accompanied by a significant enhancement of its fluorescence (lambda(max), 412 nm), and the response is highly selective to thymine base. These binding and sensing properties allow a clear detection of thymine-related mutations present in polymerase chain reaction (PCR) amplification products.     

The Relationship between Age and Change in Physical Functions after Exercise Intervention. Trainability of Japanese Community-Dwelling Older Elderly

The purposes of this study were to evaluate the relationship between age and changes in physical measurements after exercise intervention and to investigate the trainability of the older elderly. Two hundred seventy-six community-dwelling people aged 60 years and older practiced exercise intervention for 3 months. The measurements of physical functions were one-legged standing with eyes open and closed (OLS-O, OLS-C), functional reach test (FR), timed up and go test (TUG), maximum walking velocity, flexibility, and muscle strength. We evaluated the associations between age and the changes in these physical measurements. All measurements except for OLS-C significantly improved after intervention. The magnitude of the changes in hand-grip strength and FR after the intervention showed weak negative correlations with the subject''s age, but other measurements showed no correlations. In addition, there were no differences between younger elderly persons and older elderly persons with regard to changes in any measurements. These results suggested that the exercise intervention we applied could improve physical fitness in community-dwelling older people, regardless of their age. The older elderly were comparable to the younger elderly in trainability to improve physical fitness.     

Synthesis of a Strained Spherical Carbon Nanocage by Regioselective Alkyne Cyclotrimerization

The smallest spherical carbon nanocage so far, [2.2.2]carbon nanocage, has been synthesized by the cationic rhodium(I)/H₈‐binap complex‐catalyzed regioselective intermolecular cyclotrimerization of a cis‐1‐ethynyl‐4‐arylcyclohexadiene derivative followed by the triple Suzuki–Miyaura cross‐couplings with 1,3,5‐triborylbenzene and reductive aromatization. This cage molecule is highly strained, and its ring strain is between those of [6] and [5]cycloparaphenylenes. A significant red‐shift of an emission maximum was observed, compared with that of known [4.4.4]carbon nanocage. The sequential cyclotrimerizations of a cis‐1,4‐diethynylcyclohexadiene derivative with the same rhodium(I) catalyst followed by reductive aromatization failed to afford [1.1.1]carbon nanocage; instead, a β‐graph‐shaped cage molecule was generated.