Impact of fertilizer on a small watershed of Lake Biwa: use of sulfur and strontium isotopes in environmental diagnosis

Sulfur and strontium isotopes (delta(34)S and (87)Sr/(86)Sr) were determined in 39 river water samples collected over three different cultivation periods (April, May, and June), and in several materials used for comparison (fertilizers, detergents, soils, irrigation and agricultural waters), to evaluate the impact of fertilizers on a small agricultural watershed of Lake Biwa, in central Japan. delta(34)S values in river water decreased (from +5.8 to -2.0 per thousand) with increasing SO(4) concentrations (3.8 to 93.2 ppm) from upstream to downstream of the watershed. Comparison of river water S isotopes with those of possible source materials indicates that the enrichment of SO(4) can be attributed to the dissolution of two kinds of fertilizers: (1) compound fertilizers commonly used in this area and (2) ammonium sulfate which is applied on a small scale. In contrast, (87)Sr/(86)Sr values of river water decreased with time from April (avg. 0.71163), through May (avg. 0.71139), to June (avg. 0.71127). The tendency of the sample plots on the (87)Sr/(86)Sr vs. 1/Sr diagram suggests a time-dependent increase in the contribution of soil water to the river, which is partly affected by the Sr-bearing fertilizers. It is suggested that a maximum of 25% of dissolved Sr is derived from these fertilizers, while more than 75% of it is of rock origin. Mass balance calculations permitted us to evaluate the proportion of fertilizer contribution in each river. Combined use of S and Sr isotopes together with concentration data could be a new environmental diagnosis technique for rivers and soils in localized watersheds.     

Four-base codon-mediated incorporation of non-natural amino acids into proteins in a eukaryotic cell-free translation system

Various four-base codons have been shown to work for the introduction of non-natural amino acids into proteins in an Escherichia coli cell-free translation system. Here, a four-base codon-mediated non-natural mutagenesis was applied to a eukaryotic rabbit reticulocyte cell-free translation system. Mutated streptavidin mRNAs containing four-base codons were prepared and added to a rabbit reticulocyte lysate in the presence of tRNAs that were aminoacylated with a non-natural amino acid and had the corresponding four-base anticodons. A Western blot analysis of translation products indicated that the four-base codons CGGU, CGCU, CCCU, CUCU, CUAU, and GGGU were efficiently decoded by the aminoacyl-tRNAs having the corresponding four-base anticodons. In contrast, the four-base codons AGGU, AGAU, CGAU, UUGU, UCGU, and ACGU were not decoded. The stop codon-derived four-base codons UAGU, UAAU, and UGAU were found to be inefficient, whereas the amber codon UAG and opal codon UGA were efficient for the incorporation of non-natural amino acids. The application of the expanded genetic code in a eukaryotic cell-free system opens the possibility of a four-base codon-mediated incorporation of non-natural amino acids into proteins in living eukaryotic cells.     

Cu behaviors and effects of mine drainage in Kosaka River,Hokuroku mining district,Northeast Japan

Focusing on the origin of the heavy metal, this study aims to build an imputed method to estimate the heavy metal content in river water by making a distinction between the heavy metal of natural origins and that caused by human activities. Supported by GIS, Kosaka watershed within the Hokuroku basin was divided into several sub-watershed polygons and the outflows of water and Cu were calculated for each polygon. Compared with the natural origin, the dominant Cu emissions affected the river water more significantly in local. Based on the mass balance closure, the heavy metal content of Cu in the Kosaka River was estimated by the conflux accumulation of tributaries and mine drainages. The estimated Cu concentrations were checked by comparing with the actually measured values at monitoring points along the Kosaka River and the results are coincidence with each other in general. It is revealed that the mainstream water quality could be estimated by seizing the water quality of upstream tributaries and human drainages.     

Synthesis and electronic structure of proton-type partially substituted birnessite by period-four transition metal

Partially substituted proton-type birnessite were prepared by solid state reaction and their structures were refined. The formed birnessite with no substitution is identified to rhombohedral phase. In the case of substitution treatment by V and Cr for Mn, birnessite phase was not formed. On substituting Fe, hexagonal phase increased with increase of the amount of the Fe. For Co and Ni-substitution, monoclinic phase emerged at substitution ratio of around 0.37 and 0.02, respectively. For the substitution of Cu, only the monoclinic birnessite formed irrespective of the ratio. The electric conductivity of the partially substituted birnessites was examined at room temperature. The general trend is lower conductivity with increasing ratio of contained substituents. On several mol% of the substitution by Ni and Cu, the conductivity slightly increased. From DOS calculation of these compounds, the partially substitution for Mn by Fe, Co and Ni in the birnessite poses splitting of crystal field to emerge new bands at around −1 and +1 eV by Mn(IV) 3d orbital.     

Scanning transmission ion microscopy on Fudan SPM facility

In this paper,we report a novel measurement system based on the development of Fudan Scanning Proton Microscopy(SPM) facility.By using Si-PIN diode(Hamamatsu S1223-01) detector,scanning transmission ion microscopy(STIM) measurement system has been set up.It can provide density and structural images with high probing efficiency and non-destruction by utilizing the energy loss of high energy(MeV) and focused ions penetrating through a thin sample.STIM measurement is able to map the density distribution of organic elements which mostly compose biology materials,such information can not be detected by using conventional Be-windowed Si(Li) X-ray detector in Particle Induced X-ray Emission(PIXE) technique.The spatial resolution capability of STIM is higher than PIXE technique at same accelerator status.As a result of STIM measurement,Paramecium attached on the top of Kapton tube was measured by STIM.     

Enhanced activity and stability of Pt/C fuel cell anodes by the modification with ruthenium-oxide nanosheets

Ruthenium-oxide nanosheet (RuO₂ns) crystallites with thickness less than 1 nm were prepared via chemical exfoliation of a layered potassium ruthenate and deposited onto carbon supported platinum (Pt/C) as a potential co-catalyst for fuel cell anode catalysts. The electrocatalytic activity towards carbon monoxide and methanol oxidation was studied at various temperatures for different RuO₂ns loadings. An increase in electrocatalytic activity was evidenced at temperatures above 40 °C, while little enhancement in activity was observed at room temperature. The RuO₂ns modified Pt/C catalyst with composition of RuO₂:Pt = 0.5:1 (molar ratio) exhibited the highest methanol oxidation activity. CO-stripping voltammetry revealed that RuO₂ns promotes oxidation of adsorbed CO on Pt. In addition to the enhanced initial activity, the RuO₂ns modified Pt/C catalyst exhibited improved stability compared to pristine Pt/C against consecutive potential cycling tests.     

Synthesis of an AlN Polycrystalline Bulk Layer and Nanotubes by Using NH3 and Bi

A bulk layer of aluminum nitride (AlN) polycrystals was synthesized on a boron nitride crucible surface by heating Al chunks with 5 mol% of bismuth at 1273 K for 3 h under NH₃ gas flow. The fragments of the layer were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The platelet grains of AlN with a size of 0.1–1.0 μm and having preferred orientation of the c -axis perpendicular to the layer were formed at the crucible side. Nanotubes 6–15 μm long and about 20–100 nm thick grew on the gas phase side of the layer.