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We have developed a combined quantum mechanics/molecular mechanics (QM/MM) method with periodic boundary condition (PBC) treatment of explicit electron-charge interactions in a theoretically rigorous manner, for an accurate description of electronic structures for molecules in the condensed phase. The Ewald summation technique is employed for the calculation of the one-electron Hamiltonian in an ab initio framework. We decompose the Coulomb interactions into two components: those within the same cell and those between different cells. The former is calculated in the same way as the conventional QM/MM calculation for isolated systems; this article focuses on our novel method for calculating the latter type of Coulomb interactions. The detailed formulation of the Hamiltonian of this new QM/MM-PBC method, as well as the necessary one-electron integrals and their gradients, is given. The novel method is assessed by applying it to the dilute water system and a system with a coumarin molecule in water solvent; it successfully reproduces the electronic energies, frontier orbital energies, and Mulliken population charge of the real-space limit calculated by QM/MM using large isolated systems. We investigated the contribution from each term of the Hamiltonian and found that the surface-dipole term in the Ewald summation technique is indispensable for QM/MM-PBC calculations. The newly developed QM/MM-PBC method is promising for tackling chemical reactions and excited states of molecules in the condensed phase. [ABSTRACT FROM AUTHOR]

Rapid susceptibility testing for slowly growing nontuberculous mycobacteria (NTM) using a colorimetric microbial viability assay based on the reduction of the water-soluble tetrazolium salt {2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2 H-tetrazolium, monosodium salt (WST-1)} using 2,3,5,6-tetramethyl-1,4-benzoquinone as an electron mediator was developed. Using the Clinical and Laboratory Standards Institute (CLSI) method, a long-term incubation time (7-14 days) was required to determine the minimum inhibitory concentrations (MICs) of the slowly growing NTM. The MICs for a variety of different antibiotics against the slowly growing NTM were determined by the WST-1 colorimetric method and compared with those obtained using the broth microdilution methods approved by the CLSI. Good agreement was found between the MICs determined after 3-4 days using the WST-1 colorimetric method and those obtained after 10-14 days using the broth microdilution method. The results suggest that the WST-1 colorimetric assay is a useful method for the rapid determination of the MICs for the slowly growing NTM. [ABSTRACT FROM AUTHOR]

A rapid microplate method for the proliferation assay of fungi and the antifungal susceptibility testing using the colorimetric microbial viability assay based on the reduction in a tetrazolium salt 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2 H-tetrazolium, monosodium salt ( WST-8) with 2-methyl-1,4-napthoquinone as the electron mediator was developed. The proposed method was useful to measure the proliferation of 18 kinds of moulds and seven kinds of yeasts, including representative pathogens such as Aspergillus spp., Candida spp. and Cryptococcus spp. Linear relationships between the absorbance and viable fungal cell density were obtained for all fungi, suggesting that the absorbance change reflected the fungal proliferation. In addition, the minimum inhibitory concentrations ( MICs) against a variety of different pathogenic moulds and yeasts for amphotericin B, itraconazole and 5-flucytosine were determined by susceptibility testing using the proposed method and compared with those obtained using the conventional broth microdilution method. There was an excellent agreement between the results obtained using the WST-8 colorimetric method and those obtained using the conventional Clinical and Laboratory Standard Institute method. The WST-8 colorimetric assay is a useful method for rapid determination of accurate MICs for a variety of different fungi. Significance and Impact of the Study A rapid microplate method for the proliferation assay of fungi and the antifungal susceptibility testing using the colorimetric microbial viability assay based on reduction in a tetrazolium salt ( WST-8) was developed. The WST-8 colorimetric method was useful to measure the proliferation of a variety of different fungi. In the antifungal susceptibility testing, there was a good agreement between the MICs determined after 24 h using the WST-8 colorimetric method and those obtained after 48-96 h using the broth microdilution method. The proposed method was superior to conventional methods in terms of its rapidity towards a variety of different fungi. [ABSTRACT FROM AUTHOR]

We have performed ab initio path integral molecular dynamics (PIMD) simulation for the isotopomers of C2H2...HLi cluster to discuss the thermal, quantum, and isotope effects on the average geometries, which are compared with classical MD and equilibrium geometries. The π...lithium bonding with T-shape geometry is more stable than the dihydrogen bonded linear geometry by both PIMD, classical MD, and equilibrium geometry. Our ab initio PIMD simulation has clearly demonstrated the H/D isotope effect on intermolecular fluctuation, that is, the out-of-plane and in-plane fluctuations are characterized for LiH and LiD moieties, respectively. [ABSTRACT FROM AUTHOR]

As prominent characteristics of magnetic metal cluster found in vanadium sulfides, we point out marked separation and compensation of the hyperfine field at the nuclear site; these are in somewhat discordance with the common sense for 3d transition-metal magnets, where the on-site isotropic field, scaling the ordered moment magnitude, is dominant. [ABSTRACT FROM AUTHOR]

Background and objective: Neutrophils are important both for the immunological defence system and for the inflammatory tissue autoinjury mechanism. However, many local anaesthetics impair certain neutrophil functions. The aim was to assess the effects of ropivacaine, bupivacaine and lidocaine on human neutrophils from adult volunteers. Methods: Chemotaxis, phagocytosis, reactive oxygen species production, intracellular calcium ion ([Ca[sup 2+]][sub i]) concentrations and protein kinase C activity were measured in the absence and presence of ropivacaine, bupivacaine or lidocaine. The lowest concentrations of the local anaesthetics were similar to those clinically observed in the plasma. Results: Bupivacaine did not affect any neutrophil function (P > 0.05). Ropivacaine failed to change chemotaxis or phagocytosis, while lidocaine suppressed both these neutrophil functions. Ropivacaine (15, 150 µg mL[sup -1]) and lidocaine (20, 200 µg mL[sup -1]) impaired neutrophil production of O[sup -, sub 2], H[sub 2]O[sub 2] and OH (P < 0.05) at similar rates (by 7-10%). These same concentrations of ropivacaine and lidocaine suppressed [Ca[sup 2+]][sub i] elevation. Finally, neither ropivacaine nor bupivacaine inhibited protein kinase C activity, while lidocaine did. Conclusions: Suppression of the [Ca[sup 2+]][sub i] response in neutrophils by ropivacaine may represent one of the mechanisms responsible for the impairment of neutrophil functions. It should be emphasized that the inhibitory effects of ropivacaine are minor and are attained only at high concentrations, which may minimize the clinical implication of ropivacaine-associated impairment of reactive oxygen species production. Further studies using in vivo systems are required to identify the inhibitory effects of ropivacaine on reactive oxygen species production in clinical settings. [ABSTRACT FROM AUTHOR]

The magnetic properties of the intermetallic compounds Gd[sub 1 - x]Y[sub x]Mn[sub 2]Ge[sub 2] (0≤x≤0.5) (tetragonal crystal structure of the type ThCr[sub 2]Ge[sub 2]) have been measured in fields up to 40 T in the temperature range 4.2-120 K on free powders (whose particles are free to rotate in a magnetic field), fixed powders, and polycrystalline bulk samples. The temperature dependence of the crystal structure parameters of some of these intermetallic compounds was determined from x-ray diffraction measurements. It was found that the temperatures of magnetic disordering of the gadolinium magnetic subsystem and the transition of the manganese subsystem from the ferromagnetic to the antiferromagnetic state decrease as the gadolinium content is decreased, so that in compositions with x < 0.3 this transition is a first-order phase transition, and with further decrease of the gadolinium content it becomes second-order. In intermetallic compounds of this system with x = 0.3 and 0.4 another spontaneous first-order transition is observed at lower temperatures. In a magnetic field the magnetization of all the investigated intermetallic compounds except for the composition x = 0.5 undergo a metamagnetic transition. The T - x, H - x, and H - T magnetic phase diagrams are constructed. The experimental data are interpreted with allowance for the fact that according to the results of previous studies, the Mn-Mn exchange interaction is antiferromagnetic, and thus the examined intermetallic compounds are two-sublattice ferrimagnets with negative exchange interaction in one of the sublattices. Calculations performed within the framework of this model in the Yafet-Kittel approximation, which assumes that the sublattice with negative exchange can be divided into two sub-sublattices, permit a quantitative description of the experimental results in most cases. [ABSTRACT FROM AUTHOR]

Objective: This study evaluated the effects of ebastine on serum eosinophil cationic protein (ECP) levels in patients with bronchial asthma. Patients: Twenty patients with bronchial asthma (11 patients with atopic disease and nine with non-atopic disease) were enrolled in the study. Methods: In an open-label design, all patients received ebastine 10 mg/day for 4 weeks and serum ECP levels, peripheral blood eosinophil counts, morning peak expiratory flow rate (PEFR) and thresholds for airway hyper-responsiveness (Din asthgraphy) were determined before and after treatment. Results: Serum ECP levels and peripheral blood eosinophil counts were significantly decreased. By disease type, no significant change was found in the non-atopic patients, while the serum ECP level was significantly (p < 0.001) decreased in the atopic patients. Furthermore, no significant change in D was found, but PEFR was significantly (p < 0.019) increased in the atopic type. Conclusion: Ebastine not only inhibits type I allergic reactions, but may also inhibit airway inflammation by reducing serum ECP levels, particularly in patients with atopic bronchial asthma. [ABSTRACT FROM AUTHOR]

The magnetic structure of the frustrated fcc antiferromagnet GdInCu4 was investigated by NMR. Local spin configurations around In and Cu sites were found to be practically equivalent, which is consistent with the partially disordered structure proposed from 155Gd Mössbauer effect and neutron diffraction results. [ABSTRACT FROM AUTHOR]

Positive muon spin relaxation measurements were performed on a spin-1/2 system BaVS3, which shows a metal-insulator transition at TMI= 70 K. We found a marked muon-spin depolarization below TX= 30 K without appreciable critical divergence. The possibility of muonium formation in the insulating state rather than electron spin freezing is discussed taking into account the quenching of V spins evidenced by 51V NMR and NQR measurements. [ABSTRACT FROM AUTHOR]

Muon spin relaxation was measured down to 0.05 K on a geometrically frustrated metallic system, β-Mn. The observed relaxation rate increases with decreasing temperature and unexpectedly makes a peak at 0.5 K indicating a spin freezing below the temperature. Actually the asymmetry is almost recovered by applying a longitudinal magnetic field of 0.1 T. But since the tail amplitude is more than half and the dynamical relaxation is still appreciable at the lowest temperature, it is likely that the frozen moments are associated with imperfection as oxygen impurity and the intrinsic ground state is fluctuating spin liquid. [ABSTRACT FROM AUTHOR]

Mössbauer spectra were obtained for α and β-Al-Fe-Si intermetallic compounds, which are usually detected as precipitates in commercial grade Al metals. The samples were prepared by two methods, electrolytic extraction of precipitates from Al ingots and direct melting of appropriate amounts of raw materials. By the latter method, pure compounds have been obtained, whose spectra can be used as the standard spectra of these compounds to analyze the Mössbauer spectra of Al alloys. [ABSTRACT FROM AUTHOR]

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The relaxation rate of muon polarization of Y0.97Sc0.03Mn2 with a magnetic lattice composed of corner shared tetrahedrons shows a broad peak around 2.5 K indicating a random spin freezing at low temperatures. The substitution by nonmagnetic Al atoms for 10% Mn atoms raises the spin freezing temperature to 45 K. The present work shows clearly that due to the strong geometrical frustration, the ground state of the system is singlet tetrahedrons mixed with frozen paramagnetic tetrahedrons. [ABSTRACT FROM AUTHOR]

The effects of preheating temperature and annealing temperature after cold-rolling on the cube textures were studied on cold-rolled and recrystallized Al foils with different impurity contents. The density of the S-orientation in as-cold-rolled specimens is determined only by the preheating temperature and does not depend on the purity of the sample, whereas the texture of recrystallized samples is determined by both factors. In the highest purity sample (99.99 pct), a higher preheating temperature gives rise to a stronger cube texture. On the contrary, in less pure samples, a higher preheating temperature gives a weaker cube texture. This difference may be ascribed to the behavior of impurity atoms in the preheating process. Using Mössbauer spectroscopy, we have revealed the behavior of Fe atoms in Al foils subjected to the same heat and mechanical treatments and made clear the relation between the cube texture and the Fe concentration in the Al matrix. [ABSTRACT FROM AUTHOR]

A 1.43-mm-GaInAsP photonic crystal slab with a point defect cavity and line defect waveguides has been fabricated. A ˜1.5 mm- wavelength light is inserted into the waveguide and the cavity resonant spectrum observed. A 5.6 nm blue shift in the resonant peak arising from the carrier plasma effect by photopumping is also observed. These results will be applicable to all-optical switches and tunable devices. [ABSTRACT FROM AUTHOR]