The effect of ternary additions such as V, Cu, Nb, Zr and Mn as well as the deviation from the stoichiometric composition to the Al-rich composition on mechanical properties of TiAl was studied at ...room temperature (RT) in air, and RT, 873 and 1073
K in vacuum. V, Zr and Mn additions increased the bend yield stress at RT, 873 and 1073
K while Cu additions increased the yield stress at 873 and 1073
K only. The fracture stress was increased by the addition of V, Nb, Zr and Mn at RT and 873
K. The RT fracture strain was improved by additions of Nb and Mn. At 873
K by microalloying with any of the ternary elements generally tended to increase the fracture strain. The work hardening rate was increased at 873
K and decreased at 1073
K by the ternary additions investigated. The fracture strains obtained in air were about a half of those in vacuum at RT, except high V addition which seems to suppress the environmental brittleness. The fracture strain increased with increasing strain rate within 10
−5–10
−3
s
−1. The bend yield and fracture stresses and the fracture strain increased with the inverse of square root of grain size,
d
−1/2. Fractography revealed that the transgranular cleavage was a main fracture type in air and in vacuum at RT. At 873
K, the area of the intergranular fracture was larger than that at RT. The effects of microalloying elements on the mechanical properties have been discussed in terms of changes in lattice parameters, grain size, test atmosphere, strain rate, gaseous impurity elements and test temperature.
Decay particles from the s-hole states in {sup 11}B and {sup 15}N have been measured in coincidence with the quasifree {sup 12}C(p, 2p) and {sup 16}O(p, 2p) reactions at E{sub p} = 392 MeV. Triton ...decay is found to be dominant for the {sup 11}B(s-hole) state and also found to be larger than {alpha} decay for the {sup 15}N(s-hole) state despite its smaller Q value compared to {alpha} decay. Measured decay branching ratios are discussed in comparison with the results of statistical-model, SU(3)-model, and shell-model calculations. The energy spectra around the s-hole states in both {sup 11}B and {sup 15}N exhibit some bumplike structures, which can be qualitatively explained by recent shell-model calculations for both nuclei.
Intermolecular hydrophosphination of alkynes with Ph
2PH was effectively catalyzed by Yb-imine complex Yb(η
2-Ph
2CNPh)(hmpa)
3, in which the empirical rate law was described as
v
=
k catalyst
2 ...alkyne
1 phosphine
0. The active catalysts were proved to be ytterbium(II) mono- and diphosphido species generated in situ. Although trivalent phosphido complex Yb(PPh
2)
3(hmpa)
n
, gave the same results as the divalent complexes, Yb metals of the both complexes seemed to keep their original oxidation state unchanged. When Ph
2PH was substituted by Ph
2P–SiMe
3, silylphosphination of aromatic internal alkynes took place to afford 1-trimethylsilyl-2-diphenylphosphinoalkenes in moderate yields. Moreover, one-pot synthesis of 1-diphenylphosphino-1,3-butadienes from terminal alkynes and Ph
2PH has been achieved using YN(SiMe
3)
2
3 catalyst through the alkyne dimerization and subsequent hydrophosphination.
The properties of two series of oligo(2,3-dioxyfunctionalized)naphthalenes which are connected at the 1,4-positions, that is, methoxy derivatives
1–
4
and derivatives that possess two pyrene groups ...on the central scaffolding oxygen functions
5–
8
, are described. In
1–
4
, the fluorescence quantum yields increased by about 20–80% as the number of naphthalene units increased. The intramolecular energy transfer quantum yields of
5–
8
were around 20% regardless of the number of naphthalene units.
Abstract
Fibrous-type left ventricular (LV) diverticulum is usually discovered incidentally. Most fibrous diverticula are clinically silent; they may, however, cause several fatal complications, such ...as spontaneous rupture. Here, we report a case in which multiple cerebral thromboembolisms occurred while a patient with a fibrous LV diverticulum was awaiting surgery. An 81-year-old woman was diagnosed as having an LV diverticulum and was scheduled for open surgery. Following admission for correction, she complained of headache, and magnetic resonance imaging revealed multiple cerebral infarctions. We recommend surgical treatment for asymptomatic LV diverticula to prevent systemic thromboembolism.
Despite sharing many common features, adenine-binding and guanine-binding sites in proteins often show a clear preference for the cognate over the non-cognate ligand. We have analyzed electrostatic ...potential (ESP) patterns at adenine and guanine-binding sites of a large number of non-redundant proteins where each binding site was first annotated as adenine/guanine-specific or non-specific from a survey of primary literature. We show that more than 90% of ESP variance at the binding sites is accounted for by only two principal component ESP vectors, each aligned to molecular dipoles of adenine and guanine. Projected on these principal component vectors, the adenine/guanine-specific and non-specific binding sites, including adenine-containing dinucleotides, show non-overlapping distributions. Adenine or guanine specificities of the binding sites also show high correlation with the corresponding electrostatic replacement (cognate by non-cognate ligand) energies. High correlation coefficients (0.94 for 35 adenine-binding sites and 1.0 for 20 guanine-binding sites) were obtained when adenine/guanine specificities were predicted using the replacement energies. Our results demonstrate that ligand-free protein ESP is an excellent indicator for discrimination between adenine and guanine-specific binding sites and that ESP of ligand-free protein can be used as a tool to annotate known and putative purine-binding sites in proteins as adenine or guanine-specific.
The prevalence of infection with hepatitis A virus (HAV), HBV, HCV, HDV, and HEV was evaluated in 249 apparently healthy individuals, including 122 inhabitants in Ulaanbaatar, the capital city of ...Mongolia, and 127 age- and sex-matched members of nomadic tribes who lived around the capital city. Overall, hepatitis B surface antigen (HBsAg) was detected in 24 subjects (10%), of whom 22 (92%) had detectable HBV DNA. Surprisingly, HDV RNA was detectable in 20 (83%) of the 24 HBsAg-positive subjects. HCV-associated antibodies were detected in 41 (16%) and HCV RNA was detected in 36 (14%) subjects, none of whom was coinfected with HBV, indicating that HBV/HCV carriers account for one-fourth of this population. Antibodies to HAV and HEV were detected in 249 (100%) and 28 (11%) subjects, respectively. Of 22 HBV DNA-positive subjects, genotype D was detected in 21 subjects and genotype F was detected in 1 subject. All 20 HDV isolates recovered from HDV RNA-positive subjects segregated into genotype I, but these differed by 2.1 to 11.4% from each other in the 522- to 526-nucleotide sequence. Of 36 HCV RNA-positive samples, 35 (97%) were genotype 1b and 1 was genotype 2a. Reflecting an extremely high prevalence of hepatitis virus infections, there were no appreciable differences in the prevalence of hepatitis virus markers between the two studied populations with distinct living place and lifestyle. A nationwide epidemiological survey of hepatitis viruses should be conducted in an effort to prevent de novo infection with hepatitis viruses in Mongolia.
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