Identification of Al(III) species in a solution containing equimolar concentrations of Al(III) and citric acid using varying-temperature 27Al NMR spectrometry.

27Al NMR spectra of an equimolar (10 mM) Al(III)-citrate system were obtained at different temperatures. The linewidths of the signals decreased in the spectra recorded at elevated temperatures, which enabled us to unequivocally identify the resonance lines. From the spectrum recorded at 65 approximately C, a mononuclear Al(III)-citrate complex was identified at a solution pH of 3.0 in addition to trinuclear Al(III)-citrate complex, which dominated at pH 4.0.     

ESR Studies of A(1u) and A(2u) Oxoiron(IV) Porphyrin pi-Cation Radical Complexes. Spin Coupling between Ferryl Iron and A(1u)/A(2u) Orbitals

This study shows the ESR spectra of oxoiron(IV) porphyrin pi-cation radicals of 1-8 in dichloromethane-methanol (5:1) mixture. We reported in a previous paper that oxoiron(IV) porphyrin pi-cation radicals of 1-4 are in an a(1u) radical state while those of 5-8 are in an a(2u) radical. The ESR spectra (g( perpendicular)(eff) approximately 3.1 and g( parallel)(eff) approximately 2.0) for the a(1u) radical complexes, 1-4, appear quite different from those reported previously for the oxoiron(IV) porphyrin pi-cation radical of 5 (g(y) = 4.5, g(x) = 3.6, and g(z) = 1.99). The unique ESR spectra of the a(1u) radical complexes rather resemble those of compound I from Micrococcus lysodeikticus catalase (CAT) and ascorbate peroxidase (ASP). This is the first examples to mimic the ESR spectra of compound I in the enzymes. From spectral analysis based on a spin Hamiltonian containing an exchange interaction, the ESR spectra of 1-4 can be explained as a moderate ferromagnetic state (J/D approximately 0.3) between ferryl S = 1 and the porphyrin pi-cation radical S' = (1)/(2). The magnitudes of zero-field splitting (D) for ferryl iron and isotropic J value, estimated from the temperature-dependence of the half-saturation power of the ESR signals, are approximately 28 and approximately +8 cm(-1), respectively. A change in the electronegativity of the beta-pyrrole substituent hardly changes the ESR spectral feature while that of the meso-substituent slightly does owing to the change in the E/D value. On the basis of the present ESR results, we propose the a(1u) radical state for compound I of CAT and ASP.     

Effect of pH on adsolubilization of single and binary organic solutes into a cationic hydrocarbon surfactant adsorbed layer on silica

The adsolubilization behaviors of 2-naphthol, biphenyl, and their binary solutes in the hexadecyltrimethyl ammonium bromide (HTAB) adsorbed layer formed on silica have been studied with solution pH. Two feed concentrations of HTAB are employed: 1.5 and 3.0 mmol dm(-3). At the feed concentration of 1.5 mmol dm(-3) HTAB, most of HTAB are adsorbed on the silica as a monolayer, while a bilayer formation occurs at the feed concentration of 3.0 mmol dm(-3). It is found that the adsolubilized amounts of respective single solutes increase with increasing solution pH except acidic region for biphenyl under a constant feed concentration of 2-naphthol (0.4 mmol dm(-3)) and biphenyl (0.047 mmol dm(-3)). The adsolubilization of binary solutes depends on the feed concentration of HTAB; at the low HTAB feed concentration, competitive adsolubilization between 2-naphthol and biphenyl occurs above pH 4.5, while at the high HTAB feed concentration the adsolubilization of biphenyl is enhanced by the incorporation of 2-naphthol over a whole pH region. These behaviors in the adsolubilization are discussed from the surfactant structure of HTAB adsorbed as well as the admicellar partitioning coefficients.     

Nonperturbative Green's function approach to quantum field theory and arbitrariness of solutions

Green's function equations are considered for interacting spinor and (pseudo) scalar fields with interactions . These equations do not determine higher many-point functions if two-point functions are given as “input.” If vertex parts are given as input, two-point functions are determined but higher many-point functions are not determined.     

In Vivo EPR Imaging of a Perfluoroalkyl Radical in Mouse Abdomen

Although it is thought that perfluoro-2,4-dimethyl-3-isopropyl-3-pentyl (PFR-2) is a candidate for electron paramagnetic resonance (EPR) imaging agents because of its high stability, no study has been made yet on the EPR imaging of PFR-2. In this study, EPR imaging of a phantom including PFR-2 and mice that had received PFR-2 was performed by an in vivo EPR imaging system operating at an EPR frequency of 700 MHz equipped with a bridged loop-gap resonator (inner diameter, 41 mm; axial length, 10 mm). Because PFR-2 is insoluble in water, it was dissolved in perfluorocarbon. The PFR-2 solution was put in cylindrical sample tubes with various inner diameters, and these sample tubes were placed together in a larger cylindrical sample tube filled with a physiological saline solution, which was used as a phantom. The spatial resolution was estimated to be about 3 mm on the basis of EPR imaging of the phantom. EPR images of mice that had received a PFR-2 injection via the intraperitoneal route indicated that PFR-2 remained in the peritoneal cavity even 2 days after the injection. This finding suggests that it is possible to perform EPR imaging of experimental animals using PFR-2 as an imaging agent which persists in a biological system. Authors' address: Hidekatsu Yokoyama, National Institute of Advanced Industrial Science and Technology, 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya, Aichi 463-8560, Japan     

The Weight-Bearing Rate on the Paretic Limb of Cerebrovascular Hemiplegic Patients Necessary for an Independent Obstacle Negotiation Gait

Purpose: The obstacle negotiation gait (ONG) is a fundamental activity of daily living. In cerebrovascular hemiplegic patients (stroke patients), the weight-bearing rate (WBR) on the paretic limb necessary for an independent ONG was studied. Methods: One hundred and seventeen stroke patients were involved. The patients'' average age at the time of the study was 67 years, and the average time from stroke onset was 102 days. There were 68 men and 49 women. Seventy patients were right hemiplegics, and 47 were left hemiplegics. The correlations between ONG and age, sex, body mass index (BMI), time from stroke onset, muscle strength of both the paretic and non-paretic limbs, Brunnstrom stage of the lower limbs, deep sensation, and the WBR on both the paretic and non-paretic limbs were studied. Patients who could perform ONG independently and safely were categorized as the independent group (IG), and those who needed observation or any assistance were categorized as the dependent group (DG). Results: The BMI, muscle strength of both the paretic and non-paretic limbs, Brunnstrom stage of the lower limbs, deep sensation and the WBR for both the paretic and non-paretic limbs were significantly different between the IG and DG groups. In particular, the WBR on the paretic limb was found to correlate significantly with the ONG, and a WBR value of 80.5% on the paretic limb gave a clear cut-off value. Conclusion: Although multiple factors influenced the ONG of stroke patients, the WBR on the paretic limb was the most influential.     

Magnesium K‐edge XANES spectroscopy of geological standards

Magnesium K‐edge X‐ray absorption near‐edge structure (XANES) spectra have been investigated to develop a systematic understanding of a suite of Mg‐bearing geological materials such as silicate and carbonate minerals, sediments, rocks and chemical reagents. For the model compounds the Mg XANES was found to vary widely between compounds and to provide a fingerprint for the form of Mg involved in geologic materials. The energy positions and resonance features obtained from these spectra can be used to specify the dominant molecular host site of Mg, thus shedding light on Mg partitioning and isotope fractionation in geologic materials and providing a valuable complement to existing knowledge of Mg geochemistry.     

High-temperature protonic motion and low-temperature lattice deformation in one-dimensional hydrogen-bonded molecular chain in tetramethylpyrazine–chloranilic acid (1:1)

Recent theoretical advances have identified several computational algorithms that can be implemented utilizing quantum information processing (QIP), which gives an exponential speedup over the corresponding (known) algorithms on conventional computers. QIP makes use of the counter-intuitive properties of quantum mechanics, such as entanglement and the superposition principle. Unfortunately it has so far been impossible to build a practical QIP system that outperforms conventional computers. Atomic ions confined in an array of interconnected traps represent a potentially scalable approach to QIP. All basic requirements have been experimentally demonstrated in one and two qubit experiments. The remaining task is to scale the system to many qubits while minimizing and correcting errors in the system. While this requires extremely challenging technological improvements, no fundamental roadblocks are currently foreseen.