H double-quantum filtered MR imaging of joints tissues: bound water specific imaging of tendons, ligaments and cartilage

The ¹H double-quantum filtered (DQF) NMR and DQF MRI is applied to the joint tissues of rabbits for selective visualization of tendons, menisci and articular cartilage. The ¹H DQF NMR selectively filters double-quantum coherence arising from the ¹H dipolar interaction of the “bound” water in these tissues. The double-quantum creation time dependency of the DQF signal intensity is determined by the molecular environment of the “bound” water. Therefore, each tissue has a unique creation time at which the DQF signal reaches its maximum intensity, τ_max (Achilles tendon: 0.46 ± 0.02 ms, patella: 0.55 ± 0.8 ms, anterior cruciate ligament: 0.60 ± 0.05 ms, meniscus: 0.78 ± 0.02 ms, skin: 0.81 ± 0.07 ms). We have presented the creation-time-contrasted DQF images of the meniscus, patella, foot, and knee joint. Compared with conventional T₂*-weighted gradient-echo (GRE) MR images, tendons, ligaments, menisci, and articular cartilage were more clearly seen in the DQF MR images. All these tissues were distinctly discriminated from each other by their creation times. DQF MR images of foot and knee joints can selectively demonstrated tendons, ligaments, and cartilage, which make it easier to understand the complicated anatomic structure of joints. Because the DQF NMR signal intensity and τ_max are sensitive to the order structure of the “bound” water, it might be possible to introduce the creation-time dependent-contrast of ¹H DQF MR images as a new tool for analyzing the changes in the ordered structure of the tissue.     

Inaccurate mate recognition as a mating strategy of a ‘pioneer male’

Heterosubspecific mating experiments were carried out between two subspecies of cabbage butterflies, British Pieris rapae rapae and Japanese P. rapae crucivora, to examine how accurately males recognize the mates. The two subspecies are different in that the wings of female P. rapae rapae reflect little UV light, whereas those of female P. rapae crucivora are strongly UV-reflective. The wing colouration of P. rapae crucivora involving UV is believed to be critical in mate recognition. The results showed that males of both subspecies displayed mating behaviours, to and copulated with, females of both subspecies. Furthermore, P. rapae crucivora males exhibited mating behaviours and attempted to copulate with females of Pieris melete with low UV reflectance which are critically different from P. rapae crucivora females with high UV reflectance. Based on these findings, we propose the “pioneer male” hypothesis, which argues that such inaccurate mate recognition may sometimes be selectively beneficial for males and thus an adaptive mating strategy. The “pioneer male” was discussed in terms of its possible role in the evolution.     

Effect of branching in base polymer on ionic conductivity in hyperbranched polymer electrolytes

Novel hyperbranched polymer, poly[bis(diethylene glycol)benzoate] capped with a 3,5-bis[(3′,6′,9′-trioxodecyl)oxy]benzoyl group (poly-Bz1a), was prepared, and its polymer electrolyte with LiN(CF₃SO₂)₂, poly-Bz1a/LiN(CF₃SO₂)₂ electrolyte, was all evaluated in thermal properties, ionic conductivity, and electrochemical stability window. The poly-Bz1a/LiN(CF₃SO₂)₂ electrolyte exhibited higher ionic conductivity compared with a polymer electrolyte based on poly[bis(diethylene glycol)benzoate] capped with an acetyl group (poly-Ac1a), and the ionic conductivity of poly-Bz1a/LiN(CF₃SO₂)₂ electrolyte was to be 7×10⁻⁴ S cm⁻¹ at 80 °C and 1×10⁻⁶ S cm⁻¹ at 30 °C, respectively. The existence of a 3,5-bis[(3′,6′,9′-trioxodecyl)oxy]benzoyl group as a branching unit present at ends in the base polymer improved significantly ionic conductivity of the hyperbranched polymer electrolytes. The polymer electrolyte exhibited the electrochemical stability window of 4.2 V at 70 °C and was stable until 300 °C.     

Stable cavitation induces increased cytoplasmic calcium in L929 fibroblasts exposed to 1-MHz pulsed ultrasound

An increase in cytoplasmic calcium (Ca²⁺ increase) is a second messenger that is often observed under ultrasound irradiation. We hypothesize that cavitation is a physical mechanism that underlies the increase in Ca²⁺ in these experiments. To control the presence of cavitation, the wave type was controlled in a sonication chamber. One wave type largely contained a traveling wave (wave type A) while the other wave type largely contained a standing wave (wave type B). Fast Fourier transform (FFT) analysis of a sound field produced by the wave types ascertained that stable cavitation was present only under wave type A ultrasound irradiation. Under the two controlled wave types, the increase in Ca²⁺ in L929 fibroblasts was observed with fluorescence imaging. Under wave type A ultrasound irradiation, an increase in Ca²⁺ was observed; however, no increase in Ca²⁺ was observed under wave type B ultrasound irradiation. We conclude that stable cavitation is involved in the increase of Ca²⁺ in cells subjected to pulsed ultrasound.     

Microwave spectrum of 3-bromopropene in the excited torsional states

The microwave spectra in the excited states of the CC torsion for the ⁷⁹Br and ⁸¹Br isotopic species of 3-bromopropene were measured in the frequency region 15.3–23.7 GHz. The a-type R-branch and b-type Q-branch rotational transitions in the first and second excited states of one conformer, skew, have been assigned and analyzed. Analysis of the spectrum yields the rotational constants and the nuclear quadrupole coupling constants. From relative intensity measurements the energy differences associated with the CC torsion, between the ground and first excited state, the ground and second excited state have been found to lie 109 and 206 cm^?1, respectively.     

The reaction of CF3Cl and H2 in shock waves

CF₃ClH₂ mixtures highly diluted with Ar were heated to 1400–1600 K behind reflected shock waves. The HCl emission was followed in order to determine the rate constant (k₁) of the reaction, CF₃Cl + M  CF3 + Cl + M, and k₁ = 2.1 × 10¹⁷ exp(?75000/RT) cm³ mol^?1 s^?1 was computed.     

Investigation of failure during elongational flow of polymer melts

A basic study of the mechanisms of necking and ductile failure of polymer melts in uniaxial elongational flow has been carried out. A linear stability analysis was carried out using a White—Metzner convected Maxwell model with a deformation-rate-dependent relaxation time, which varies according to τ = τ_o/(1 + aτ_o[2trd²]^{$\text{1}\text{2}$}). It was shown that filament stability and elongation to break depend upon τ_oE, where E is the elongation rate, and a. At fixed τ_oE, filament stability decreases with increasing a. At small a, stability increases with increasing τ_oE while for a > $\text{1}\text{√3}$, stability decreases with increasing τ_oE. For a material with small a, ductile failure can occur for small τ_oE, but cohesive fracture should be the cause of failure at larger τ_oE. For a material with large a, however, ductile failure always dominates the failure mode. These results are used to interpret failure in elongational flow of low density and high density polyethylene and polypropylene melts and describe how the latter two melts exhibit ductile failure.     

Functional monomers and polymers. XCVII. Synthesis of oligomer models of polyethyleneimine derivatives containing pendant thymine bases

A series of oligomer models of polyethyleneimine derivatives having pendant thymine bases were prepared by the reaction of carboxyethyl derivatives of thymine with oligomer amines using an activated-ester method. It was found that the hypochromicity values obtained from UV spectra and pKa values obtained from spectrophotometric titrations depend on the chain length of the oligomers and the thymine content of the polymers.     

A stochastic model for solitons

The soliton physics for the propagation of waves is represented by a stochastic model in which the particles of the wave can jump ahead according to some probability distribution. We demonstrate the presence of a steady state (stationary distribution) for the wavelength. It is shown that the stationary distribution is a convolution of geometric random variables. Approximations to the stationary distribution are investigated for a large number of particles. The model is rich and includes Gaussian cases as limit distribution for the wavelength (when suitably normalized). A sufficient Lindeberg‐like condition identifies a class of solitons with normal behavior. Our general model includes, among many other reasonable alternatives, an exponential aging soliton, of which the uniform soliton is one special subcase (with Gumbel's stationary distribution). With the proper interpretation, our model also includes the deterministic model proposed in Takahashi and Satsuma [A soliton cellular automaton, J Phys Soc Japan 59 (1990), 3514–3519]. © 2003 Wiley Periodicals, Inc. Random Struct. Alg., 2004     

Thermal decomposition of 1-butyne in shock waves

1-Butyne diluted with Ar was heated behind reflected shock waves over the temperature range of 1100–1600 K and the total density range of 1.36 × 10^?5?1.75 × 10^?5 mol/cm³. Reaction products were analyzed by gas-chromatography. The progress of the reaction was followed by IR laser kinetic absorption spectroscopy. The products were CH₄, C₂H₂, C₂H₄, C₂H₆, allene, propyne, C₄H₂, vinylacetyiene, 1,2- butadiene, 1,3-butadiene, and benzene. The present data were successfully modeled with a 80 reaction mechanism. 1-Butyne was found to isomerize to 1,2-butadiene. The initial decomposition was dominated by 1-butyne → C₃H₃ + CH₃ under these conditions. Rate constant expressions were derived for the decomposition to be k₇ = 3.0 × 10¹⁵ exp(?75800 cal/RT) s^?1 and for the isomerization to be k₄ = 2.5 × 10¹³ exp(?65000 cal/RT) s^?1. The activation energy 75.8 kcal/mol was cited from literature value and the activation energy 65 kcal/mol was assumed. These rate constant expressions are applicable under the present experimental conditions, 1100–1600 K and 1.23–2.30 atm. © 1995 John Wiley & Sons, Inc.