Cd adsorption onto Pseudomonas putida in the presence and absence of extracellular polymeric substances   总被引：1，自引：0，他引：1  

Masato Ueshima 《Geochimica et cosmochimica acta》2008,72(24):5885-5895

The role of bacterial extracellular polymeric substances (EPS) in metal adsorption was determined by studying Cd adsorption onto the gram-negative bacterial species Pseudomonas putida with and without enzymatic removal of EPS from the biomass material. A range of experimental approaches were used to characterize the Cd adsorption reactions, including bulk proton and Cd adsorption measurements, FTIR spectroscopy, and fluorescence microscopy. The proton-reactivities of the biomass samples with EPS are not significantly different from those obtained for EPS-free biomass. Similarly, the presence of EPS does not significantly affect the extent of Cd removal from solution by the biomass on a mass-normalized basis, based on bulk Cd adsorption measurements conducted as a function of pH, nor does it appear to strongly affect the Cd-binding groups as observed by FTIR. However, fluorescence microscopy indicates that Cd, although concentrated on cell walls, is also bound to some extent to EPS. Together, the results from this study suggest that the P. putida EPS can bind significant concentrations of Cd from solution, and that the nature and mass-normalized extent of the binding is similar to that of the cell wall. Therefore, the EPS-bearing systems do not exhibit enhanced mass-normalized removal of Cd from solution relative to the EPS-free systems. The presence of the EPS effectively increases the viability of cells exposed to aqueous Cd, likely due to sequestration of the Cd away from the cells due to Cd-EPS binding.  相似文献   

Stable isotope and chemical composition of pearls: Biomineralization in cultured pearl oysters in ago bay, Japan     

Hodaka Kawahata  Mayuri Inoue  Masato Nohara  Atsushi Suzuki 《Journal of Oceanography》2006,62(4):405-412

The δ¹⁸O, δ¹³C and trace element composition of pearls collected from Ago Bay, Japan, were investigated in order to evaluate biomineralization in the cultured pearl oyster (Pinctada fucata martensii). The oxygen isotopic data suggest that the pearls were produced around 23–24°C, mainly in June to early July, which is consistent with their occurrence in the field. Therefore the pearls were produced under or close to isotopic equilibrium conditions, although they showed high calcification rates (higher than 0.2–1.0 g cm^{− 2}yr⁻¹) under which, for example, coral skeletons (calcification rate ∼0.28 g cm^{− 2}yr⁻¹) often show non-equilibrium isotope partitioning. The δ¹³C values were ∼− 2.9‰ lower than those calculated for offshore waters under equilibrium conditions. This may be due to low-δ¹³C bottom waters resulting from the degradation of organic matter (OM) or to a contribution of low-δ ¹³C food. In the latter case, a simple mass balance calculation gives a respiration component of 14%. Twelve trace elements of bulk pearl samples were classified into four groups on the basis of their enrichment/depletion patterns relative to seawater and inter-element relationships: group 1, Co, Cr, Pb; group 2, Ba, Cs, U; group 3, Cu, Sn, V, and group 4, Mn, Rb, Mo. Comparison with coral skeletons suggests that Ba and Mn (groups 2 and 4) were definitely much enriched in proteinaceous OM relative to aragonite crystals in pearls and that V (group 3) in pearls showed only slight enrichment in the organicrich layer. By contrast, the other elements showed small differences between both layers (enrichment factor of <3), suggesting that these elements occur largely in aragonite crystals.  相似文献   

Response of plant growth to surface water balance during a summer dry period in the Kazakhstan steppe     

Yoshihiro Iijima  Tsuneo Kawaragi  Takehiko Ito  Kanat Akshalov  Atsushi Tsunekawa  Masato Shinoda 《水文研究》2008,22(16):2974-2981

In drylands, water deficit is the primary factor limiting plant growth. In the present study, surface energy balance and plant growth (above‐ground and below‐ground biomass) were measured continuously during the 2002 growing season in semiarid grassland in the northern part of Kazakhstan, Central Asia. Although there was above normal total rainfall during the 2002 growing season (May–November; 244 mm over 183 days), there was a dry period during July and August. Evaporative water was effectively supplied by precipitation and surface soil moisture during the wet season (May and June), during which time above‐ground biomass increased. During the early stages of the dry period, mature plants were likely to tap deeper sources of soil moisture, representing stored snowmelt water. As the soil moisture content decreased during the summer dry period due to the high levels of evapotranspiration and lack of precipitation, the evaporative fraction and above‐ground biomass rapidly decreased, whereas the below‐ground biomass increased. These results suggest that in summer, soil moisture acts to store water, and that soil moisture is essential for plant growth as a direct source of water during the dry period in natural grasslands in the Kazakhstan steppe. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Short-term variability of Jupiter’s extended sodium nebula     

Mizuki Yoneda  Masato Kagitani  Shoichi Okano 《Icarus》2009,204(2):589-596

Ground-based optical observations of D₁ and D₂ line emissions from Jupiter’s sodium nebula, which extend over several hundreds of jovian radii, were carried out at Mt. Haleakala, Maui, Hawaii using a wide field filter imager from May 19 to June 21, 2007. During this observation, the east-west asymmetry of the nebula with respect to the Io’s orbital motion was clearly identified. Particularly, the D₁+D₂ brightness on the western side of Jupiter is strongly controlled by the Io phase angle. The following scenario was developed to explain this phenomenon as follows: First, more ionospheric ions like NaX⁺, which are thought to produce fast neutral sodium atoms due to a dissociative recombination process, are expected to exist in Io’s dayside hemisphere rather than in the nightside one. Second, it is expected that more NaX⁺ ionospheric ions are picked up by the jovian co-rotating magnetic field when Io’s leading hemisphere is illuminated by the Sun. Third, the sodium atom ejection rate varies with respect to Io’s orbital position as a result of the first two points. Model simulations were performed using this scenario. The model results were consistent with the observation results, suggesting that Io’s ionosphere is expected to be controlled by solar radiation just like Earth.  相似文献   

Near-field beam pattern measurement of qualification model of ALMA band 8 (385–500 GHz) cartridge receiver     

Masato Naruse  Tetsuya Ito  Yutaro Sekimoto  Hiroyuki Toba  Naohisa Satou  Masahiro Sugimoto  Wenlei Shan  Yoshizou Iizuka  Toshiaki Kamba  Mamoru Kamikura  Yasutaka Serizawa 《Experimental Astronomy》2009,24(1-3):89-107

We have developed a near-field vector beam measurement system covering the range of frequencies from 385 to 500 GHz. The measurement set-up is capable of measurements with dynamic range exceeding 50 dB and amplitude and phase stability respectively of 0.1 dB/h and 1 degree/5 min at room temperature. Beam patterns of the ALMA band 8 corrugated horns and receiver optics block were measured at room temperature and lately compared with physical optics calculations obtained in the far-field. Both co-polar and cross-polar beam patterns of a qualification model of the ALMA band 8 cartridge cooled in a cartridge-test-cryostat have also been measured in the near-field as a detector of a submillimeter vector network analyzer. The measurements presented in this work refer to the lowest, middle and upper frequencies of band 8. The comparisons between software model and experimental measurements at these frequencies show good agreement down to ?30 dB for the main polarization component. The cross-polarization level of the beam propagating through the receiver optics block was also characterized. We found that a cross-polarization level better than ?28 dB can be achieved at all measured frequencies. The measured beam pattern of this receiver corresponds to efficiency of greater than 92% at the sub reflector (diameter of 750 mm) of the ALMA 12 m optics.  相似文献   

Design formulas for tuned mass dampers based on A perturbation technique     

Yozo Fujino  Masato Ab 《地震工程与结构动力学》1993,22(10):833-854

Modal properties of tuned mass damper (TMD)-structure two-degree-of-freedom (2DOF) linear systems are studied employing a perturbation technique. Using the perturbation solutions, formulas relevant to designing the TMD for various types of loading are obtained; they are expressed as a function of mass ratio, tuning ratio, damping ratio of the TMD and damping ratio of the structure. Equivalent additional dampings of the structure due to the TMD are derived for random and harmonic forces. Matched expressions of equivalent damping, which are valid for detuned, i.e. non-optimal, conditions are also presented. The stability boundary of TMD-structure systems subject to linear self-excited forces is derived in a closed form. Using the perturbation solutions, procedures for optimizing the TMD parameters for various types of loading are explained and the optimal values are derived. The formulas obtained in this study can be used with good accuracy for mass ratios less than 0.02.  相似文献   

The orientation of the OH− dipole in an optically anisotropie crystal: An application to the OH− dipole in topaz     

Keiji Shinoda  Nobuyuki Aikawa 《Physics and Chemistry of Minerals》1994,21(1-2):24-28

For the purpose of determining the orientation of the OH^? dipole in an optically anisotropic crystal, distribution of polarized IR absorbance is formulated under Fourier transform microspectroscopy. The formulatd absorbance distribution suggests that the degree of pleochroism of absorbance depends on the angle between the orientation of the OH^? dipole and the principal orientation of the optically anisotropic crystal. As its application, the general orientation of the OH^? dipole in topaz is determined to be inclined 27.3° from the c-axis in (010).  相似文献   

Concentrations of Trace Elements in Carbonate Reference Materials Coral JCp-1 and Giant Clam JCt-1 by Inductively Coupled Plasma-Mass Spectrometry   总被引：1，自引：0，他引：1  

Mayuri Inoue  Masato Nohara  Takashi Okai  Atsushi Suzuki  Hodaka Kawahata 《Geostandards and Geoanalytical Research》2004,28(3):411-416

Trace elements in the Geological Survey of Japan carbonate reference materials Coral JCp-1 and Giant Clam JCt-1 were determined by inductively coupled plasma-mass spectrometry after digestion with 2% v/v HNO₃. A standard addition method was adopted in this determination in order to neutralise the Ca matrix effect. In addition, Sc, Y, In and Bi were used as internal standards to control the matrix effect and correct instrumental drift. Of the eighteen elements measured in JCp-1, precisions for fourteen elements, including Cu, Cd and Ba, were better than 10% RSD and concentrations ranged from 0.002 μg g^-1 (Cs) to 8.02 μg g^-1 (Ba). The concentrations of measured trace elements in JCt-1, except for Cu, were lower than those in JCp-1. Precisions for all elements with concentrations higher than 0.04 μg g^-1 in JCt-1 were also better than 10% RSD and concentrations were found to be between 0.001 μg g^-1 (Cs) and 4.84 μg g^-1 (Ba). The concentrations of more than fifteen trace elements in the aragonite reference materials are reported here for the first time. Both reference materials are suitable for use in geochemical studies of environmental reconstruction based upon biogenic carbonate materials.  相似文献   

Exsolution textures in orthopyroxene in aluminous granulites as indicators of UHT metamorphism: New evidence from the Eastern Ghats Belt, India   总被引：1，自引：0，他引：1  

Sankar Bose  Kaushik Das  Somnath Dasgupta  Hiroyuki Miura  Masato Fukuoka 《Lithos》2006,92(3-4):506-523

Highly aluminous orthopyroxene, coexisting with sapphirine, cordierite, sillimanite, quartz and garnet in various combinations, constitute granoblastic mosaic peak metamorphic assemblages in aluminous granulites from three localities in the Eastern Ghats Belt, India. Orthopyroxene contains four types of intergrowths: (a) involving sapphirine with or without cordierite, (b) involving spinel, but without sapphirine, (c) involving cordierite, but without sapphirine and spinel, and (d) involving garnet, without sapphirine, spinel or cordierite. On the basis of textural and compositional data, origin of the intergrowths is ascribed to breakdown of Mg-Tschermak component, locally also involving Fe- and Ti-Tschermak. An attempt is made to compute the “pre-breakdown” compositions of orthopyroxene by image analysis, which shows maximum Al₂O₃ content of 13.4 wt.% in the pristine orthopyroxene. Geothermometry, phase equilibria consideration and application of existing experimental data on alumina solubility in orthopyroxene coexisting with sapphirine and quartz, collectively indicate extreme thermal conditions of metamorphism (> 1000 °C) for the studied assemblages. This re-affirms the notion that Al₂O₃ solubility in orthopyroxene is the most powerful indicator of UHT metamorphism (Harley, S.L., 2004. Extending our understanding of ultrahigh temperature crustal metamorphism. J. Mineral. Petrol. Sci. 99, 140–158). The intergrowths are considered to have formed due to cooling from the thermal peak spanning a temperature range of approximately 150 °C. Appearance of diverse types of intergrowths is probably related to subtle differences in bulk composition, particularly Fe:Mg ratios.  相似文献   

Recursive evaluation of interaction forces of unbounded soil in the time domain from dynamic-stiffness coefficients in the frequency domain     

John P. Wolf  Masato Motosaka 《地震工程与结构动力学》1989,18(3):365-376

The interaction forces of the linear unbounded soil in a non-linear soil-structure-interaction analysis can be calculated recursively, starting directly from the dynamic-stiffness coefficients in the frequency domain. Two possibilities of choosing a recursive equation are discussed.

• (i) The recursive equation in the frequency domain. For each frequency, the interaction force at a specific time station is expressed as a function of the corresponding interaction force at the previous time station and of the displacements at the current time station and at the two most recent past time stations. This recursive evaluation of the convolution integral. which can be derived using the z-transformation, is rigorous. By using interpolation in the frequency domain, an approximate procedure results, which leads to a significant reduction in computational effort.
• (ii) The recursive equation in the time domain. By approximating the dynamic-stiffness coefficients as the ratios of two polynomials in frequency using a curve-fitting technique based on the least-squares method and by applying the partial-fraction expansion and using the z-transformation, the recursive coefficients can be determined explicitly. Alternatively, the ratio of two polynomials can also be transformed to an ordinary differential equation together with the initial conditions.

The recursive equations using interpolation in the frequency domain and based on a ratio of two polynomials lead to a reduction in the computational effort of one and up to three orders of magnitude, respectively.  相似文献